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Home | Alpha Telephone | Domain Names | Web Hosting | Get Traffic | xrEvidence | xrSoccer United States Patent
Coordinate position inputting/detecting device, a method for inputting/detecting the coordinate position, and a display board system In the coodinate-position inputting/detecting device, the light receiving/emitting devices emit light beams spreading in a fan shape and travelling along an entry area. The light receiving/emitting device also receiving the light beam reflected by a recursive reflecting member and detect the distribution of the intensity of the received light beam. The coordinates of a position of a pointing body such as a user's fingertip or a pen inserted in the entry area is identified using the distribution of intensity detected by the light receiving/emitting devices.
Attorney, Agent or Firm: What is claimed is: 1. A coordinate-position inputting/detecting device comprising: at least two light emitting means each for emitting light beams traveling along an entry area having a specified area; reflecting means provided at a specified location in a peripheral section of the entry area for reflecting incident light beams emitted from each of said light emitting means back towards substantially the same respective light paths as the incident light beams; at least two intensity-distribution detecting means each for receiving the light beams reflected by said reflecting means and for detecting the distribution of the intensity of the received light; coordinate-value identifying means for identifying the coordinates of a blocked position where the light beam traveling along the entry area is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting means; minimum-value identifying means for identifying minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting means; computing means for computing a time differentiation value of the coordinates identified by said coordinate-value identifying means; storing means for storing therein at least one of the minimum values identified by said minimum-value identifying means, the coordinates identified by said coordinate-value identifying means and the time differentiation values computed by said computing means in a correlated form; and determining means for determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said storing means, wherein the determining means determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting means includes a light source that emits light in a direction substantially perpendicular to a surface of the entry area towards a half-mirror, and wherein the half-mirror reflects the light emitted by the light source towards the reflecting means so as to emit light beams traveling in a substantially parallel direction to the surface of the entry area, and the light beams reflected by the reflecting means pass through the half-mirror and are detected by the at least two detecting means. 2. A coordinate-position inputting/detecting device according to claim 1; wherein said light emitting means forms a light beam from a light source in a fan shape and emits the fan-shaped light beam. 3. A coordinate-position inputting/detecting device according to claim 2; wherein one light source is provided for all of said light emitting means or one light source is provided for each of said light emitting means. 4. A coordinate-position inputting/detecting device according to claim 2; wherein said light emitting means comprises a light converging system for converging a light beam from said light source to form a fan shape light beam. 5. A coordinate-position inputting/detecting device according to claim 1; wherein the intensity-distribution detecting means comprises: light converging means for converging the light reflected by said reflecting means; and light-receiving means provided in the downstream side from said light converging means for outputting an electric signal according to the distribution of intensity of the converged light. 6. A coordinate-position inputting/detecting device according to claim 5; wherein said intensity-distribution detecting means comprises a slit instead of said light converging means for leading the light reflected by said reflecting means to said light-receiving means. 7. A coordinate-position inputting/detecting device according to claim 5; wherein said coordinate-value identifying means comprises: dark point detecting means for detecting the dark points on said light-receiving means generated due to blocking of a light beam within said entry area according to the electric signals outputted from each of said light-receiving means; and first computing means for computing the coordinates of the light-blocked position using the position of the dark points detected by said dark point detecting means. 8. A coordinate-position inputting/detecting device according to claim 5; wherein said coordinate-value identifying means comprises: dark point detecting means for detecting the dark points on said light-receiving means generated due to blocking of a light beam within said entry area according to the electric signal outputted from each of said light-receiving means; storing means for storing therein coordinate information obtained by previously correlating the coordinates within said entry area to each combination of the dark points detected by said dark point detecting means; and selecting means for selecting the coordinates corresponding to the combination of the relative positions of the dark points detected by said dark point detecting means as the coordinates of the light-blocked position. 9. A coordinate-position inputting/detecting device according to claim 7; wherein said coordinate-value identifying means further comprises: intensity-value identifying means for identifying the light intensity values of the dark points detected by said dark point detecting means respectively according to electric signals outputted from said light-receiving means; second computing unit for computing a time differentiation of the coordinates obtained by said first computing means; storing means for storing therein at least one of the light intensity values identified by said intensity-value identifying means, the coordinates obtained by said first computing means and the time-differentiated value obtained by said second computing means in a correlated form; and determining means for determining the contents of an operation performed in said entry area according to the previously prepared condition and at least one of the light intensity values, coordinates and the time-differentiated values each stored in said storage means. 10. A coordinate-position inputting/detecting device according to claim 9; wherein said determining means uses a result of previous determination concerning the contents of the operation as one of the conditions. 11. A coordinate-position inputting/detecting device according to claim 8; wherein said coordinate-value identifying means further comprises: intensity-value identifying means for identifying the light intensity values of the dark points detected by said dark point detecting means respectively according to the electric signals outputted from said light-receiving means; first computing means for computing a time differentiation of coordinates selected by said selecting means; storing means for storing therein at least one of the light intensity values identified by said intensity-value identifying means, the coordinates selected by said selecting means and the time-differentiated value obtained by said first computing means in a correlated form; and determining unit for determining the contents of an operation performed in said entry area according to the previously prepared condition and at least one of the light intensity values, coordinates and the time-differentiated values stored in said storing means. 12. A coordinate-position inputting/detecting device according to claim 11; wherein said determining means uses a result of previous determination concerning the contents of the operation as one of the conditions. 13. A coordinate-position inputting/detecting device according to claim 1; wherein said determining means uses a result of previous determination concerning the contents of the operation as one of the conditions. 14. A coordinate-position inputting/detecting device according to claim 1; wherein said entry area is formed, when the coordinate-position inputting/detecting device is to be attached in front of the display surface of a display unit, of the size that matches with the size of the display surface. 15. A coordinate-position inputting/detecting device according to claim 1; wherein said entry area is formed, when the coordinate-position inputting/detecting device is to be attached in front of a write-in surface for writing freehand characters and graphics, of the size that matches with the size of the write-in surface. 16. A coordinate-position inputting/detecting device comprising: frame means having a specified form; at least two light emitting means each for emitting a light beam toward an internal side of said frame; entry area means formed in the internal side of said frame means due to the intersecting light beams emitted from said light emitting means; reflecting means provided at a specified location in said frame means for reflecting incident light beams emitted from each of said light emitting means back towards substantially the same respective light paths as the incident light beams; at least two intensity-distribution detecting means each for receiving a light beam reflected by said reflecting means and for detecting the distribution of the intensity of the received light; coordinate-value identifying means for identifying, when a light beam within said entry area is blocked, coordinates of a blocked position where the light beam is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting means; minimum-value identifying means for identifying minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting means; computing means for computing a time differentiation value of the coordinates identified by said coordinate-value identifying means; storing means for storing therein at least one of the minimum values identified by said minimum-value identifying means, the coordinates identified by said coordinate-value identifying means and the time differentiation values computed by said computing means in a correlated form; and determining means for determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said storing means, wherein the determining means determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting means includes a light source that emits light in a direction substantially perpendicular to a surface of the entry area means towards a half-mirror, and wherein the half-mirror reflects the light emitted by the light source towards the reflecting means so as to emit light beams traveling in a substantially parallel direction to the surface of the entry area means, and the light beams reflected by the reflecting means pass through the half-mirror and are detected by the at least two detecting means. 17. A coordinate-position inputting/detecting device according to claim 16; wherein said light emitting means forms a light beam from a light source in a fan shape and emits the fan-shaped light beam. 18. A coordinate-position inputting/detecting device according to claim 17; wherein one light source is provided for all of said light emitting means or one light source is provided for each of said light emitting means. 19. A coordinate-position inputting/detecting device according to claim 17; wherein said light emitting means comprises a light converging system for converging a light beam from said light source to form a fan shape light beam. 20. A coordinate-position inputting/detecting device according to claim 16; wherein the intensity-distribution detecting means comprises: light converging means for converging the light reflected by said reflecting means; and light-receiving means provided in the downstream side from said light converging lens for outputting an electric signal according to the distribution of intensity of the converged light. 21. A coordinate-position inputting/detecting device according to claim 20; wherein said intensity-distribution detecting means comprises a slit instead of said light converging means for leading the light reflected by said reflecting means to said light-receiving means. 22. A coordinate-position inputting/detecting device according to claim 20; wherein said coordinate-value identifying means comprises: dark point detecting means for detecting the dark points on said light-receiving means generated due to blocking of a light beam within said entry area according to the electric signals outputted from each of said light-receiving means; and first computing means for computing the coordinates of the light-blocked position using the position of the dark points detected by said dark point detecting means. 23. A coordinate-position inputting/detecting device according to claim 22; wherein said coordinate-value identifying means further comprises: intensity-value identifying means for identifying the light intensity values of the dark points detected by said dark point detecting means respectively according to electric signals outputted from said light-receiving means; second computing unit for computing a time differentiation of the coordinates obtained by said first computing means; storing means for storing therein at least one of the light intensity values identified by said intensity-value identifying means, the coordinates obtained by said first computing means and the time-differentiated value obtained by said second computing means in a correlated form; and determining means for determining the contents of an operation performed in said entry area according to the previously prepared condition and at least one of the light intensity values, coordinates and the time-differentiated values each stored in said storage means. 24. A coordinate-position inputting/detecting device according to claim 23; wherein said determining means uses a result of previous determination concerning the contents of the operation as one of the conditions. 25. A coordinate-position inputting/detecting device according to claim 20; wherein said coordinate-value identifying means comprises: dark point detecting means for detecting the dark points on said light-receiving means generated due to blocking of a light beam within said entry area according to the electric signal outputted from each of said light-receiving means; storing means for storing therein coordinate information obtained by previously correlating the coordinates within said entry area to each combination of the dark points detected by said dark point detecting means; and selecting means for selecting the coordinates corresponding to the combination of the relative positions of the dark points detected by said dark point detecting means as the coordinates of the light-blocked position. 26. A coordinate-position inputting/detecting device according to claim 25; wherein said coordinate-value identifying means further comprises: intensity-value identifying means for identifying the light intensity values of the dark points detected by said dark point detecting means respectively according to the electric signals outputted from said light-receiving means; first computing means for computing a time differentiation of coordinates selected by said selecting means; storing means for storing therein at least one of the light intensity values identified by said intensity-value identifying means, the coordinates selected by said selecting means and the time-differentiated value obtained by said first computing means in a correlated form; and determining unit for determining the contents of an operation performed in said entry area according to the previously prepared condition and at least one of the light intensity values, coordinates and the time-differentiated values stored in said storing means. 27. A coordinate-position inputting/detecting device according to claim 26; wherein said determining means uses a result of previous determination concerning the contents of the operation as one of the conditions. 28. A coordinate-position inputting/detecting device according to claim 16; wherein at least said light emitting means, said reflecting means and said intensity-distribution detecting means are integrated with said frame means. 29. A coordinate-position inputting/detecting device according to claim 16; wherein said determining means uses a result of previous determination concerning the contents of the operation as one of the conditions. 30. A coordinate position inputting/detecting device according to claim 16; wherein said entry area is formed, when the coordinate-position inputting/detecting device is to be attached in front of the display surface of a display unit, of the size that matches with the size of the display surface. 31. A coordinate-position inputting/detecting device according to claim 16; wherein said entry area is formed, when the coordinate-position inputting/detecting device is to be attached in front of a write-in surface for writing freehand characters and graphics, of the size that matches with the size of the write-in surface. 32. A coordinate-position inputting/detecting device comprising: at least two light emitting units each configured to emit light beams traveling along an entry area having a specified area; a reflecting unit provided at a specified location in a peripheral section of the entry area and configured to reflect incident light beams emitted from each of said light emitting units back towards substantially the same light paths as the incident light beams; at least two intensity-distribution detecting units each configured to receive the light beams reflected by said reflecting unit and to detect the distribution of the intensity of the received light; a coordinate-value identifying unit configured to identify the coordinates of a blocked position where the light beam traveling along the entry area is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting units; a minimum-value identifying unit configured to identify minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting units; a computing unit configured to compute a time differentiation value of the coordinates identified by said coordinate-value identifying unit; a memory configured to store at least one of the minimum values identified by said minimum-value identifying unit, the coordinates identified by said coordinate-value identifying unit and the time differentiation values computed by said computing unit in a correlated form; and a determining unit configured to determine the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said memory, wherein the determining unit determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting units includes a light source that emits light in a direction substantially perpendicular to a surface of the entry area towards a half-mirror, and wherein the half-mirror reflects the light emitted by the light source towards the reflecting unit so as to emit light beams traveling in a substantially parallel direction to the surface of the entry area, and the light beams reflected by the reflecting unit pass through the half-mirror and are detected by the at least two detecting units. 33. A coordinate-position inputting/detecting device comprising: a frame having a specified form; at least two light emitting units each configured to emit a light beam toward an internal side of the frame; an entry area formed in the internal side of the frame due to the intersecting light beams emitted from said light emitting units; a reflecting unit provided at a specified location in said frame and configured to reflect incident light beams emitted from each of said light emitting units back towards substantially the same respective light paths as the incident light beams; at least two intensity-distribution detecting units each configured to receive a light beam reflected by said reflecting unit and to detect the distribution of the intensity of the received light; a coordinate-value identifying unit configured to identify, when a light beam within said entry area is blocked, coordinates of a blocked position where the light beam is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting units; a minimum-value identifying unit configured to identify minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting units; a computing unit configured to compute a time differentiation value of the coordinates identified by said coordinate-value identifying unit; a memory configured to store at least one of the minimum values identified by said minimum-value identifying unit, the coordinates identified by said coordinate-value identifying unit and the time differentiation values computed by said computing unit in a correlated form; and a determining unit configured to determine the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said memory, wherein the determining unit determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting units includes a light source that emits light in a direction substantially perpendicular to a surface of the entry area towards a half-mirror, and wherein the half-mirror reflects the light emitted by the light source towards the reflecting unit so as to emit light beams traveling in a substantially parallel direction to the surface of the entry area, and the light beams reflected by the reflecting unit pass through the half-mirror and are detected by the at least two detecting units. 34. A method for inputting/detecting coordinate-position comprising the steps of: emitting light beams traveling along an entry area with at least two light emitting units, said entry area having a specified area; reflecting incident light beams emitted from each of said light emitting units with a reflecting unit back towards substantially the same respective light paths as the incident light beams, said reflecting unit provided at a specified location in a peripheral section of said entry area; receiving the light beams reflected by said reflecting unit and detecting the distribution of the intensity of the received light with at least two intensity-distribution detecting units; identifying a position on said entry area at which the light beams traveling along the entry area are blocked with a coordinate-value identifying unit according to the distribution of the intensity of the received light detected by each of said intensity-distribution detecting units; identifying minimum values of the distribution of intensity detected by each of said intensity-distribution detecting units with a minimum-value identifying unit; computing a time differentiation value of the coordinates identified by said coordinate-value identifying unit with a computing unit; storing in a memory at least one of the minimum values identified by said minimum-value identifying unit, the coordinates identified by said coordinate-value identifying unit and the time differentiation values computed by said computing unit in a correlated form; and determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said memory, wherein the determining step determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting units includes a light source that emits light in a direction substantially perpendicular to a surface of the entry area towards a half-mirror, and wherein the half-mirror reflects the light emitted by the light source towards the reflecting unit so as to emit light beams traveling in a substantially parallel direction to the surface of the entry area, and the light beams reflected by the reflecting unit pass through the half-mirror and are detected by the at least two detecting units. 35. A method for inputting/detecting coordinate-position comprising the steps of: emitting light beams towards an internal side of a frame with at least two light emitting units, said frame having a specified form; forming an entry area inside the frame due to an intersection of light beams emitted from said light emitting units; reflecting incident light beams emitted from each of said light emitting units back towards substantially the same respective light paths as the incident light beams with a reflecting unit, said reflecting unit provided at a specified location in said frame; receiving the light beams reflected by said reflecting unit and detecting the distribution of the intensity of the received light with at least two intensity-distribution detecting units; identifying a position on said entry area at which the light beams traveling along said entry area are blocked with a coordinate-value identifying unit according to the distribution of the intensity of the received light detected by each of said intensity-distribution detecting units; identifying minimum values of the distribution of intensity detected by each of said intensity-distribution detecting units with a minimum-value identifying unit; computing a time differentiation value of the coordinates identified by said coordinate-value identifying unit with a computing unit; storing in a memory at least one of the minimum values identified by said minimum-value identifying unit, the coordinates identified by said coordinate-value identifying unit and the time differentiation values computed by said computing unit in a correlated form; and determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said memory, wherein the determining step determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting units includes a light source that emits light in a direction substantially perpendicular to a surface of the entry area towards a half-mirror, and wherein the half-mirror reflects the light emitted by the light source towards the reflecting unit so as to emit light beams traveling in a substantially parallel direction to the surface of the entry area, and the light beams reflected by the reflecting unit pass through the half-mirror and are detected by the at least two detecting units. 36. A display board system comprising: display means for displaying thereon characters and images; a coordinate-position inputting/detecting device with an entry area provided in the front surface of said display means; and a control means for providing controls over display of said display means according to input from said coordinate-position inputting/detecting device, said display board system for forming a display surface and a write-in surface of a display board using said display means and said coordinate-position inputting/detecting device; wherein said coordinate-position inputting/detecting device includes: at least two light emitting means each for emitting a light beam traveling along an entry area having a specified area; reflecting means provided at a specified location in a peripheral section of the entry area for reflecting incident light beams emitted from each of said light emitting means back towards substantially the same respective light paths as the incident light beams; at least two intensity-distribution detecting means each for receiving a light beam reflected by said reflecting means and for detecting the distribution of the intensity of the received light; coordinate-value identifying means for identifying the coordinates of a blocked position where the light beam traveling along the entry area is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting means; minimum-value identifying means for identifying minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting means; computing means for computing a time differentiation value of the coordinates identified by said coordinate-value identifying means; storing means for storing therein at least one of the minimum values identified by said minimum-value identifying means, the coordinates identified by said coordinate-value identifying means and the time differentiation values computed by said computing means in a correlated form; and determining means for determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said storing means, wherein the determining means determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting means includes a light source that emits light in a direction substantially perpendicular to a surface of the entry area towards a half-mirror, and wherein the half-mirror reflects the light emitted by the light source towards the reflecting means so as to emit light beams traveling in a substantially parallel direction to the surface of the entry area, and the light beams reflected by the reflecting means pass through the half-mirror and are detected by the at least two detecting means. 37. A display board system according to claim 36; wherein said display means is a plasma display. 38. A display board system according to claim 36; wherein said display means further has a plurality of connecting means for connecting various types of information equipment and AV equipment such as a digital camera, a DVD player, and video equipment, and is usable as a large-sized screen monitor. 39. A display board system comprising: display means for displaying thereon characters and images; a coordinate-position inputting/detecting device with an entry area provided in the front surface of said display means; and control means for providing controls over display of said display means according to input from said coordinate-position inputting/detecting device, said display board system for forming a display surface and a write-in surface of a display board using said display means and said coordinate-position inputting/detecting device; wherein said coordinate-position inputting/detecting device includes: frame means having a specified form; at least two light emitting means each for emitting a light beam toward an internal side of said frame means; an entry area formed in the internal side of said frame means due to the intersecting light beams emitted from said light emitting means; reflecting means provided at a specified location in said frame for reflecting incident light beams emitted from each of said light emitting means back towards substantially the same respective light paths as the incident light beams; at least two intensity-distribution detecting means each for receiving a light beam reflected by said reflecting means and for detecting the distribution of the intensity of the received light; coordinate-value identifying means for identifying, when a light beam within said entry area is blocked, coordinates of a blocked position where the light beam is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting means; minimum-value identifying means for identifying minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting means; computing means for computing a time differentiation value of the coordinates identified by said coordinate-value identifying means; storing means for storing therein at least one of the minimum values identified by said minimum-value identifying means, the coordinates identified by said coordinate-value identifying means and the time differentiation values computed by said computing means in a correlated form; and determining means for determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said storing means, wherein the determining means determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting means includes a light source that emits light in a direction substantially perpendicular to a surface of the entry area towards a half-mirror, and wherein the half-mirror reflects the light emitted by the light source towards the reflecting means so as to emit light beams traveling in a substantially parallel direction to the surface of the entry area, and the light beams reflected by the reflecting means pass through the half-mirror and are detected by the at least two decting means. 40. A display board system according to claim 39; wherein said display means is a plasma display. 41. A display board system according to claim 39; wherein said display means further has a plurality of connecting means for connecting various types of information equipment and AV equipment such as a digital camera, a DVD player, and video equipment, and is usable as a large-sized screen monitor. 42. A display board system comprising: display means for displaying thereon characters and images; a coordinate-position inputting/detecting device with an entry area provided in the front surface of said display means; printing means for outputting image data onto a recording paper; and control means for providing controls over the display of said display means as well as over printing operations of said printing means according to input from said coordinate-position inputting/detecting device, said display board system for forming a display surface and a write-in surface of the display board using said display means and said coordinate-position inputting/detecting device; wherein said coordinate-position inputting/detecting device includes: at least two light emitting means each for emitting a light beam traveling along an entry having a specified area; reflecting means provided at a specified location in a peripheral section of the entry area for reflecting incident light beams emitted from each of said light emitting means back towards substantially the same respective light paths as the incident light beams; at least two intensity-distribution detecting means each for receiving a light beam reflected by said reflecting means and for detecting the distribution of the intensity of the received light; coordinate-value identifying means for identifying the coordinates of a blocked position where the light beam traveling along the entry area is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting means; minimum-value identifying means for identifying minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting means; computing means for computing a time differentiation value of the coordinates identified by said coordinate-value identifying means; storing means for storing therein at least one of the minimum values identified by said minimum-value identifying means, the coordinates identified by said coordinate-value identifying means and the time differentiation values computed by said computing means in a correlated form; and determining means for determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said storing means, wherein the determining means determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting means includes a light source that emits light in a direction substantially perpendicular to a surface of the entry area towards a half-mirror, and wherein the half-mirror reflects the light emitted by the light source towards the reflecting means so as to emit light beams traveling in a substantially parallel direction to the surface of the entry area, and the light beams reflected by the reflecting means pass through the half-mirror and are detected by the at least two detecting means, wherein said control means is a personal computer, wherein the display board system further comprises: holding means for holding a display surface and a write-in surface of the display board at a specified height; and printer accommodating means for accommodating said printing means therein, and a control accommodating means for accommodating said control means therein, in which said control accommodating means, said printer accommodating means and said holding means are arranged in the vertical direction in this order from the bottom. 43. A display board system according to claim 42; wherein said display means is a plasma display. 44. A display board system according to claim 42; further comprising a keyboard placement section provided at a position on the upper side of said printer accommodating means but on the lower side of said holding means for placing a keyboard connected to said personal computer. 45. A display board system according to claim 42; wherein said holding means comprises an angle adjusting means for adjusting an angle of a display surface and a write-in surface of the display board. 46. A display board system according to claim 42; wherein said display means further has a plurality of connecting means for connecting various types of information equipment and AV equipment such as a digital camera, a DVD player, and video equipment, and is usable as a large-sized screen monitor. 47. A display board system comprising: display means for displaying thereon characters and images; a coordinate-position inputting/detecting device with an entry area provided in the front surface of said display means; printing means for outputting image data onto a recording paper; and control means for providing controls over the display of said display means as well as over printing operations of said printing means according to input from said coordinate-position inputting/detecting device, said display board system for forming a display surface and a write-in surface of the display board using said display means and said coordinate-position inputting/detecting device; wherein said coordinate-position inputting/detecting device includes: frame means having a specified form; at least two light emitting means each for emitting a light beam toward an internal side of said frame means; an entry area formed in the internal side of said frame means due to the intersecting light beams emitted from said light emitting means; reflecting means provided at a specified location in said frame means for reflecting incident light beams emitted from each of said light emitting means back towards substantially the same respective light paths as the incident light beams; at least two intensity-distribution detecting means each for receiving a light beam reflected by said reflecting means and for detecting the distribution of the intensity of the received light; coordinate-value identifying means for identifying, when a light beam within said entry area is blocked, coordinates of a blocked position where the light beam is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting means; minimum-value identifying means for identifying minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting means; computing means for computing a time differentiation value of the coordinates identified by said coordinate-value identifying means; storing means for storing therein at least one of the minimum values identified by said minimum-value identifying means, the coordinates identified by said coordinate-value identifying means and the time differentiation values computed by said computing means in a correlated form; and determining means for determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said storing means, wherein the determining means determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting means includes a light source that emits light in a direction substantially perpendicular to a surface of the entry area towards a half-mirror, and wherein the half-mirror reflects the light emitted by the light source towards the reflecting means so as to emit light beams traveling in a substantially parallel direction to the surface of the entry area, and the light beams reflected by the reflecting means pass through the half-mirror and are detected by the at least two detecting means, wherein said control means is a personal computer, wherein the display board system further comprises: holding means for holding a display surface and a write-in surface of the display board at a specified height; and printer accommodating means for accommodating said printing means therein, and a control accommodating means for accommodating said control means therein, in which said control accommodating means, said printer accommodating means and said holding means are arranged in the vertical direction in this order from the bottom. 48. A display board system according to claim 47; wherein said display means is a plasma display. 49. A display board system according to claim 47; wherein said frame means has a keyboard placement means provided at a position on the upper side of said printer accommodating means but on the lower side of said holding means for placing a keyboard connected to said personal computer. 50. A display board system according to claim 47; wherein said holding means comprises an angle adjusting means for adjusting an angle of a display surface and a write-in surface of the display board. 51. A display board system according to claim 47; wherein said display means further has a plurality of connecting means for connecting various types of information equipment and AV equipment such as a digital camera, a DVD player, and video equipment, and Is usable as a large-sized screen monitor. 52. A coordinate-position inputting/detecting device comprising: at least two light emitting means each for emitting light beams traveling along an entry area having a specified area; reflecting means provided at a specified location in a peripheral section of the entry area for reflecting incident light beams emitted from each of said light emitting means back towards substantially the same respective light paths as the incident light beams; at least two intensity-distribution detecting means each for receiving the light beams reflected by said reflecting means and for detecting the distribution of the intensity of the received light; coordinate-value identifying means for identifying the coordinates of a blocked position where the light beam traveling along the entry area is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting means; minimum-value identifying means for identifying minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting means; computing means for computing a time differentiation value of the coordinates identified by said coordinate-value identifying means; storing means for storing therein at least one of the minimum values identified by said minimum-value identifying means, the coordinates identified by said coordinate-value identifying means and the time differentiation values computed by said computing means in a correlated form; and determining means for determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said storing means, wherein the determining means determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting means includes a light source that emits light in a direction substantially parallel to a surface of the entry area through a half-mirror towards the reflecting means, and wherein the half-mirror reflects the light reflected by the reflecting means substantially perpendicular towards the at least two detecting means so as to be detected by the at least two detecting means. 53. A coordinate-position inputting/detecting device comprising: frame means having a specified form; at least two light emitting means each for emitting a light beam toward an internal side of said frame; entry area means formed in the internal side of said frame means due to the intersecting light beams emitted from said light emitting means; reflecting means provided at a specified location in said frame means for reflecting incident light beams emitted from each of said light emitting means back towards substantially the same respective light paths as the incident light beams; at least two intensity-distribution detecting means each for receiving a light beam reflected by said reflecting means and for detecting the distribution of the intensity of the received light; coordinate-value identifying means for identifying, when a light beam within said entry area is blocked, coordinates of a blocked position where the light beam is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting means; minimum-value identifying means for identifying minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting means; computing means for computing a time differentiation value of the coordinates identified by said coordinate-value identifying means; storing means for storing therein at least one of the minimum values identified by said minimum-value identifying means, the coordinates identified by said coordinate-value identifying means and the time differentiation values computed by said computing means in a correlated form; and determining means for determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said storing means, wherein the determining means determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting means includes a light source that emits light in a direction substantially parallel to a surface of the entry area means through a half-mirror towards the reflecting means, and wherein the half-mirror reflects the light reflected by the reflecting means substantially perpendicular towards the at least two detecting means so as to be detected by the at least two detecting means. 54. A coordinate-position inputting/detecting device comprising: at least two light emitting units each configured to emit light beams traveling along an entry area having a specified area; a reflecting unit provided at a specified location in a peripheral section of the entry area and configured to reflect incident light beams emitted from each of said light emitting units back towards substantially the same light paths as the incident light beams; at least two intensity-distribution detecting units each configured to receive the light beams reflected by said reflecting unit and to detect the distribution of the intensity of the received light; a coordinate-value identifying unit configured to identify the coordinates of a blocked position where the light beam traveling along the entry area is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting units; a minimum-value identifying unit configured to identify minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting units; a computing unit configured to compute a time differentiation value of the coordinates identified by said coordinate-value identifying unit; a memory configured to store at least one of the minimum values identified by said minimum-value identifying unit, the coordinates identified by said coordinate-value identifying unit and the time differentiation values computed by said computing unit in a correlated form; and a determining unit configured to determine the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said memory, wherein the determining unit determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting units includes a light source that emits light in a direction substantially parallel to a surface of the entry area through a half-mirror towards the reflecting unit, and wherein the half-mirror reflects the light reflected by the reflecting unit substantially perpendicular towards the at least two detecting units so as to be detected by the at least two detecting units. 55. A coordinate-position inputting/detecting device comprising: a frame having a specified form; at least two light emitting units each configured to emit a light beam toward an internal side of the frame; an entry area formed in the internal side of the frame due to the intersecting light beams emitted from said light emitting units; a reflecting unit provided at a specified location in said frame and configured to reflect incident light beams emitted from each of said light emitting units back towards substantially the same respective light paths as the incident light beams; at least two intensity-distribution detecting units each configured to receive a light beam reflected by said reflecting unit and to detect the distribution of the intensity of the received light; a coordinate-value identifying unit configured to identify, when a light beam within said entry area is blocked, coordinates of a blocked position where the light beam is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting units; a minimum-value identifying unit configured to identify minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting units; a computing unit configured to compute a time differentiation value of the coordinates identified by said coordinate-value identifying unit; a memory configured to store at least one of the minimum values identified by said minimum-value identifying unit, the coordinates identified by said coordinate-value identifying unit and the time differentiation values computed by said computing unit in a correlated form; and a determining unit configured to determine the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said memory, wherein the determining unit determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting units includes a light source that emits light in a direction substantially parallel to a surface of the entry area through a half-mirror towards the reflecting unit, and wherein the half-mirror reflects the light reflected by the reflecting unit substantially perpendicular towards the at least two detecting units so as to be detected by the at least two detecting units. 56. A method for inputting/detecting coordinate-position comprising the steps of: emitting light beams traveling along an entry area with at least two light emitting units, said entry area having a specified area; reflecting incident light beams emitted from each of said light emitting units with a reflecting unit back towards substantially the same respective light paths as the incident light beams, said reflecting unit provided at a specified location in a peripheral section of said entry area; receiving the light beams reflected by said reflecting unit and detecting the distribution of the intensity of the received light with at least two intensity-distribution detecting units; identifying a position on said entry area at which the light beams traveling along the entry area are blocked with a coordinate-value identifying unit according to the distribution of the intensity of the received light detected by each of said intensity-distribution detecting units; identifying minimum values of the distribution of intensity detected by each of said intensity-distribution detecting units with a minimum-value identifying unit; computing a time differentiation value of the coordinates identified by said coordinate-value identifying unit with a computing unit; storing in a memory at least one of the minimum values identified by said minimum-value identifying unit, the coordinates identified by said coordinate-value identifying unit and the time differentiation values computed by said computing unit in a correlated form; and determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said memory, wherein the determining step determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting units includes a light source that emits light in a direction substantially parallel to a surface of the entry area through a half-mirror towards the reflecting unit, and wherein the half-mirror reflects the light reflected by the reflecting unit substantially perpendicular towards the at least two detecting units so as to be detected by the at least two detecting units. 57. A method for inputting/detecting coordinate-position comprising the steps of: emitting light beams towards an internal side of a frame with at least two light emitting units, said frame having a specified form; forming an entry area inside the frame due to an intersection of light beams emitted from said light emitting units; reflecting incident light beams emitted from each of said light emitting units back towards substantially the same respective light paths as the incident light beams with a reflecting unit, said reflecting unit provided at a specified location in said frame; receiving the light beams reflected by said reflecting unit and detecting the distribution of the intensity of the received light with at least two intensity-distribution detecting units; identifying a position on said entry area at which the light beams traveling along said entry area are blocked with a coordinate-value identifying unit according to the distribution of the intensity of the received light detected by each of said intensity-distribution detecting units; identifying minimum values of the distribution of intensity detected by each of said intensity-distribution detecting units with a minimum-value identifying unit; computing a time differentiation value of the coordinates identified by said coordinate-value identifying unit with a computing unit; storing in a memory at least one of the minimum values identified by said minimum-value identifying unit, the coordinates identified by said coordinate-value identifying unit and the time differentiation values computed by said computing unit in a correlated form; and determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said memory, wherein the determining step determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting units includes a light source that emits light in a direction substantially parallel to a surface of the entry area through a half-mirror towards the reflecting unit, and wherein the half-mirror reflects the light reflected by the reflecting unit substantially perpendicular towards the at least two detecting units so as to be detected by the at least two detecting units. 58. A display board system comprising: display means for displaying thereon characters and images; a coordinate-position inputting/detecting device with an entry area provided in the front surface of said display means; and a control means for providing controls over display of said display means according to input from said coordinate-position inputting/detecting device, said display board system for forming a display surface and a write-in surface of a display board using said display means and said coordinate-position inputting/detecting device; wherein said coordinate-position inputting/detecting device includes: at least two light emitting means each for emitting a light beam traveling along an entry area having a specified area; reflecting means provided at a specified location in a peripheral section of the entry area for reflecting incident light beams emitted from each of said light emitting means back towards substantially the same respective light paths as the incident light beams; at least two intensity-distribution detecting means each for receiving a light beam reflected by said reflecting means and for detecting the distribution of the intensity of the received light; coordinate-value identifying means for identifying the coordinates of a blocked position where the light beam traveling along the entry area is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting means; minimum-value identifying means for identifying minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting means; computing means for computing a time differentiation value of the coordinates identified by said coordinate-value identifying means; storing means for storing therein at least one of the minimum values identified by said minimum-value identifying means, the coordinates identified by said coordinate-value identifying means and the time differentiation values computed by said computing means in a correlated form; and determining means for determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said storing means, wherein the determining means determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetennined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting means includes a light source that emits light in a direction substantially parallel to a surface of the entry area through a half-mirror towards the reflecting means, and wherein the half-mirror reflects the light reflected by the reflecting means substantially perpendicular towards the at least two detecting means so as to be detected by the at least two detecting means. 59. A display board system comprising: display means for displaying thereon characters and images; a coordinate-position inputting/detecting device with an entry area provided in the front surface of said display means; and control means for providing controls over display of said display means according to input from said coordinate-position inputting/detecting device, said display board system for forming a display surface and a write-in surface of a display board using said display means and said coordinate-position inputting/detecting device; wherein said coordinate-position inputting/detecting device includes: frame means having a specified form; at least two light emitting means each for emitting a light beam toward an internal side of said frame means; an entry area formed in the internal side of said frame means due to the intersecting light beams emitted from said light emitting means; reflecting means provided at a specified location in said frame for reflecting incident light beams emitted from each of said light emitting means back towards substantially the same respective light paths as the incident light beams; at least two intensity-distribution detecting means each for receiving a light beam reflected by said reflecting means and for detecting the distribution of the intensity of the received light; coordinate-value identifying means for identifying, when a light beam within said entry area is blocked, coordinates of a blocked position where the light beam is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting means; minimum-value identifying means for identifying minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting means; computing means for computing a time differentiation value of the coordinates identified by said coordinate-value identifying means; storing means for storing therein at least one of the minimum values identified by said minimum-value identifying means, the coordinates identified by said coordinate-value identifying means and the time differentiation values computed by said computing means in a correlated form; and determining means for determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said storing means, wherein the determining means determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting means includes a light source that emits light in a direction substantially parallel to a surface of the entry area through a half-mirror towards the reflecting means, and wherein the half-mirror reflects the light reflected by the reflecting means substantially perpendicular towards the at least two detecting means so as to be detected by the at least two detecting means. 60. A display board system comprising: display means for displaying thereon characters and images; a coordinate-position inputting/detecting device with an entry area provided in the front surface of said display means; printing means for outputting image data onto a recording paper; and control means for providing controls over the display of said display means as well as over printing operations of said printing means according to input from said coordinate-position inputting/detecting device, said display board system for forming a display surface and a write-in surface of the display board using said display means and said coordinate-position inputting/detecting device; wherein said coordinate-position inputting/detecting device includes: at least two light emitting means each for emitting a light beam traveling along an entry having a specified area; reflecting means provided at a specified location in a peripheral section of the entry area for reflecting incident light beams emitted from each of said light emitting means back towards substantially the same respective light paths as the incident light beams; at least two intensity-distribution detecting means each for receiving a light beam reflected by said reflecting means and for detecting the distribution of the intensity of the received light; coordinate-value identifying means for identifying the coordinates of a blocked position where the light beam traveling along the entry area is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting means; minimum-value identifying means for identifying minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting means; computing means for computing a time differentiation value of the coordinates identified by said coordinate-value identifying means; storing means for storing therein at least one of the minimum values identified by said minimum-value identifying means, the coordinates identified by said coordinate-value identifying means and the time differentiation values computed by said computing means in a correlated form; and determining means for determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said storing means, wherein the determining means determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting means includes a light source that emits light in a direction substantially parallel to a surface of the entry area through a half-mirror towards the reflecting means, and wherein the half-mirror reflects the light reflected by the reflecting means substantially perpendicular towards the at least two detecting means so as to be detected by the at least two detecting means, wherein said control means is a personal computer, wherein the display board system further comprises: holding means for holding a display surface and a write-in surface of the display board at a specified height; and printer accommodating means for accommodating said printing means therein, and a control accommodating means for accommodating said control means therein, in which said control accommodating means, said printer accommodating means and said holding means are arranged in the vertical direction in this order from the bottom. 61. A display board system comprising: display means for displaying thereon characters and images; a coordinate-position inputting/detecting device with an entry area provided in the front surface of said display means; printing means for outputting image data onto a recording paper; and control means for providing controls over the display of said display means as well as over printing operations of said printing means according to input from said coordinate-position inputting/detecting device, said display board system for forming a display surface and a write-in surface of the display board using said display means and said coordinate-position inputting/detecting device; wherein said coordinate-position inputting/detecting device includes: frame means having a specified form; at least two light emitting means each for emitting a light beam toward an internal side of said frame means; an entry area formed in the internal side of said frame means due to the intersecting light beams emitted from said light emitting means; reflecting means provided at a specified location in said frame means for reflecting incident light beams emitted from each of said light emitting means back towards substantially the same respective light paths as the incident light beams; at least two intensity-distribution detecting means each for receiving a light beam reflected by said reflecting means and for detecting the distribution of the intensity of the received light; coordinate-value identifying means for identifying, when a light beam within said entry area is blocked, coordinates of a blocked position where the light beam is blocked by using the distribution of intensity detected by each of said intensity-distribution detecting means; minimum-value identifying means for identifying minimum intensity values of the distribution of intensity detected by each of said intensity-distribution detecting means; computing means for computing a time differentiation value of the coordinates identified by said coordinate-value identifying means; storing means for storing therein at least one of the minimum values identified by said minimum-value identifying means, the coordinates identified by said coordinate-value identifying means and the time differentiation values computed by said computing means in a correlated form; and determining means for determining the contents of an operation performed in said entry area according to a previously prepared condition and at least one of the minimum values, the coordinates and the time-differentiated values stored in said storing means, wherein the determining means determines the contents of the operation performed in the entry area is a pointing state when an absolute value of a time differentiation value is larger than a predetermined time differentiation threshold, and a minimum intensity value is smaller than a first predetermined intensity threshold but larger than a second predetermined intensity threshold, said first predetermined intensity threshold being larger than said second predetermined intensity threshold, wherein each of the at least two emitting means includes a light source that emits light in a direction substantially parallel to a surface of the entry area through a half-mirror towards the reflecting means, and wherein the half-mirror reflects the light reflected by the reflecting means substantially perpendicular towards the at least two detecting means so as to be detected by the at least two detecting means, wherein said control means is a personal computer, wherein the display board system further comprises: holding means for holding a display surface and a write-in surface of the display board at a specified height; and printer accommodating means for accommodating said printing means therein, and a control accommodating means for accommodating said control means therein, in which said control accommodating means, said printer accommodating means and said holding means are arranged in the vertical direction in this order from the bottom. FIELD OF THE INVENTION The present invention relates to a method and device for inputting/detecting the coordinate position and a display board system and more particularly, to a method and device for inputting/detecting the coordinate position with improved operability and reliability as well as a display board system which uses the coordinate-position inputting/detecting device. BACKGROUND OF THE INVENTION Conventionally there has been known a display board which can read freehand information written on a whiteboard or a write-in surface of a write-in sheet with some writing tool using a dedicated scanner and output the read information onto a recording paper with a dedicated printer. While, in recent years, there has also been suggested a display board system In which a coordinate-position inputting/detecting device is provided in a write-in surface of a display board for enabling inputting of freehand information written in the write-in surface in real time. For instance, the Soft Board manufactured and provided by the Microfield Graphics, Inc. is a device having a coordinate-position inputting/detecting device provided on a whiteboard, and being capable of acquiring visual data Such as characters and pictures drawn on the whiteboard into a computer in real time. With the display board system using this Soft Board, it is possible to input visual data captured with the Soft Board into a computer for displaying the data on a CRT thereof, to display the data on a large-sized screen using a liquid crystal projector, or to output the data with a printer onto a recording paper. It is also possible to project an image on a screen of a computer with the Soft Board connected thereto onto the Soft Board with a liquid crystal projector and operate the computer on the screen of the Soft Board. There has also been disclosed a display board system having a display unit for displaying characters and images thereon, a coordinate-position inputting/detecting device with a coordinate-position input surface (a touch panel) provided on a front surface of the display unit, and a control unit for providing controls over display by the display unit according to input from the coordinate-position inputting/detecting device. This system forms a display surface and a write-in surface of the display board by making use of the display unit and the touch input device. For instance, in a case of the Smart 2000 manufactured and supplied by the SMART Technologies Inc., in a state where an image of a character, a picture, or a graphics is projected with a liquid crystal projector connected to a computer onto a panel, freehand information is captured into the computer using a coordinate-position inputting/detecting device (write-in surface) provided on a front surface of the projection surface (display surface) of the panel. Then, the freehand information is synthesized with the image information in the computer, and the synthesized information can be displayed again with the liquid crystal projector in real time. There has been disclosed a display board system in the U.S. patent application Ser. No. 9/299,052 (filing date Apr. 4, 1999), the contents of which are incorporated in the present invention by reference. The a display board system can display an image inputted by the coordinate-position inputting/detecting device superimposed on an image on the screen displayed by the display unit as an overwrite image, so that the display board system has been used for conferences, presentation, or educational purposes and its effect in actual use has been highly evaluated. When a communicating function for transferring audio or video data is integrated with the display board system as described above, the display board system can also be used as an electronic conference system by connecting remote sites with a communication line. By the way, as a coordinate-position inputting/detecting device used in the display board system as described above, devices described below are known according to a difference between input methods thereof. As a first case, there is a coordinate-position inputting/detecting device having a coordinate-position input surface with wires provided in a grid pattern in the X-Y direction and a dedicated pen for generating a magnetic field and used in a state where a current is passed through the wire. In this coordinate-position inputting/detecting device, when a user points to a desired position by making a dedicated pen contact or bringing the same closer to the coordinate-position input surface for some input operation, an electrical change is generated at the pointed position. The coordinate-position inputting/detecting device detects the coordinates of the position pointed by the dedicated pen according to electrical changes generated as described above on the coordinate-position input surface, and executes the processing of inputting the detected coordinates into a computer. As a second case, there is a coordinate-position inputting/detecting device having a coordinate-position input surface with a resistive film such as conductive rubber. In this coordinate-position inputting/detecting device, when a user points to a desired position by making a pen contact the coordinate-position input surface for some input operation, a resistance value at the pointed position changes due to the pressure applied to the coordinate-position input surface by the pen. The coordinate-position inputting/detecting device detects the coordinates of the position pointed by the pen according to a change in the resistance values on the coordinate-position input surface, and executes the processing of inputting the detected coordinates into a computer. Furthermore, as a third case, there is known an optical type of coordinate-position inputting/detecting device having at least two light emitting sections each for emitting a light beam through, for example, a rotating polygon mirror and scanning a coordinate-position input surface with the emitted light beam (Refer to Japanese Patent Laid-Open Publication No. SHO 57-211637). At least two light receiving sections are provided for receiving the light beam reflected with a dedicated pen having a reflecting member provided at the tip thereof inserted in a coordinate-position input surface. It should be noted that the coordinate-position input surface of the coordinate-position inputting/detecting device is not a physical surface like the coordinate-position input surface of the coordinate-position inputting/detecting device in the first and second cases, but is a surface formed with the light beams emitted from the light emitting sections. In this coordinate-position inputting/detecting device, when a user points a desired position on the coordinate-position input surface with the dedicated pen for some input operation, the light beams emitted from the light emitting sections are reflected by the reflecting member of the dedicated pen. The coordinate-position inputting/detecting device receives the reflected light beams, detects the coordinates of the position pointed by the user using the principle of triangulation, and executes the processing of inputting the detected coordinates into a computer. Of those coordinate-position inputting/detecting devices described above, the optical type of coordinate-position inputting/detecting device described as the third case seems a promising device to us after consideration on an appropriate system to be applied in the a display board system. More specifically, the coordinate-position inputting/detecting device according to the first case has a problem associated with operability in a display board system requiring a large type of coordinate-position inputting/detecting device because a dedicated pen which generates a magnetic field and a main body of the device are connected to each other through a cable. The coordinate-position inputting/detecting devices in the first and second cases have problem that transparency of the coordinate-position input surface is reduced because wire or a resistive film has to be provided on the coordinate-position input surface. Accordingly, when any of the coordinate-position inputting/detecting devices is attached to the front surface of a display unit, for instance, there occurs inconvenience that the information appearing on the display unit is difficult to be seen. Furthermore, the coordinate-position inputting/detecting devices in the first and second cases have difficulty in upsizing and require high manufacturing cost, which is not suitable to be applied to such a system like the display board system that needs a large-sized screen display. On the other hand, the optical type of coordinate-position inputting/detecting device as the third case is a system in which the coordinates of a position on the coordinate-position input surface pointed by the user are detected by scanning the coordinate-position input surface with light beams and receiving the light beams reflected by the dedicated pen. Hence, the device in the third case does not create any problem even when the device is mounted on the surface of the display unit and used, and upsizing thereof is also comparatively easier. Accordingly, the coordinate-position inputting/detecting device in the third case is thought preferable as a coordinate-position inputting/detecting device used for display board system. In addition, the coordinate-position inputting/detecting device in the third case excellent in operability and viewability of a display unit is also thought preferable to be used even when the device is mounted on the display unit of an ordinary-sized computer taking into consideration the problems in the coordinate-position inputting/detecting devices in the first and second cases. It should be noted that a coordinate-position inputting/detecting device related to the optical type of coordinate-position inputting/detecting device having described as the third case is disclosed in Japanese Patent Laid-Open Publication No. HEI 9-91094 and Japanese Patent Laid-Open Publication No. HEI 9-319501. With the coordinate-position inputting/detecting device in the third case, however, as a dedicated pen with a reflecting member provided at the tip thereof is required, input operation with, for example, a fingertip, is not allowed, which is inconvenient. In addition, when the dedicated pen is lost or damaged, the input operation can not be carried out. Though it can be considered that only a reflecting member is formed as a discrete device and used by mounting on a user's finger or a pen, a mechanism for mounting is complicated or there occurs the need to prepare various types of mounting mechanism because of variations in a form and a size of pens to be used and of variations in a size and a length of user's finger. Furthermore, even if the same reflecting member is used, the reflecting characteristic varies according to the difference in their sizes and forms, hence, stable detection of a coordinate position can not be carried out. The coordinate-position inputting/detecting device in the third case uses a mechanical system such as a rotating polygon mirror and a motor for rotating the rotating polygon mirror for scanning the coordinate-position input surface with light beams. Therefore, there is a problem that vibrations in the device occur due to the mechanical system, which causes reduction of reliability of detecting a position or occurrence of noise therein. SUMMARY OF THE INVENTION It is an object of the present invention to improve, for the purpose of solving the problems described above, operability and usability of a method and device for inputting/detecting the coordinate position by enabling specification of coordinates of a position in an entry area pointed thereto with an arbitrary pointing body such as a fingertip or an ordinary pen without using a particular pointing device. It is another object of the present invention to enhance reliability of a device for inputting/detecting the coordinate position by preventing occurrence of vibrations therein. It is another object of the present invention to improve workability and adaptability to handling of a display board system by using the coordinate-position inputting/detecting device with excellent operability and high reliability. In the present invention, at least two light emitting units are provided that emit a light beam travelling along an entry area, at least two intensity-distribution detecting units are provided that receive a light beam reflected by a reflecting unit and detects distribution of the intensity of the received light, and a coordinate-value identifying unit is provided in order to identity the coordinates of a blocked position where the light beam travelling along the entry area is blocked by using each distribution of intensity detected by the intensity-distribution detecting units. Accordingly, with the present invention, a user can perform a desired input operation only by blocking a portion of the light travelling along the entry area with an arbitrary pointing body such as a user's finger or a pen. In the present invention, each of at least two light emitting units emit a light beam toward an inner side of a frame to form an entry area in the inner side thereof, each of at least two intensity-distribution detecting units receive a light beam reflected by a reflecting member provided in a specified location of the frame and detect distribution of the intensity of the received light. Further, a coordinate-value identifying unit identifies a blocked position using the detected distribution of intensity. Accordingly, with the present invention, a user can perform a desired input operation only by blocking a portion of the light within the entry area with an arbitrary pointing body such as a user's finger or a pen. In the present invention, the light emitting unit forms light from a light source into a fan shape and emits the fan-shaped light beams so that the emitted light beams cover the entry area or a substantially entire area of the inner side of the frame. In the present invention, one unit of light source may be provided for all the light emitting units or one unit of light source may be provided for each of the light emitting units. In the present invention, a light converging system converges light from the light source to form fan shape light beams, so that a light that can cover most of the area of the inner side of the frame can be emitted. Accordingly, with the present invention, the need for preparing a mechanical system such as a rotating polygon mirror used for scanning an entry area with a light beam can be eliminated. In the present invention, a light converging lens converges the light reflected by the reflecting unit, and a light-receiving element receives the light converged by the light converging lens and outputs an electric signal according to the distribution of intensity of the received light. More specifically, the light reflected by the reflecting unit is converged by the light converging lens at a different incident angle with respect to the light-receiving element, so that the light-receiving element can easily detect the distribution of intensity of the light. In the present invention, the light reflected by the reflecting unit is led to the light-receiving element through a slit, and the light-receiving element receives the light converged by a light converging lens and outputs an electric signal according to the distribution of intensity of the received light, with which the distribution of intensity of the light can be detected. More specifically, the light reflected by the reflecting unit is converged by the slit at a different incident angle with respect to the light-receiving element, so that the light-receiving element can easily detect the distribution of intensity of the light. In the present invention, dark points generated on the light-receiving elements due blocking of the light beam in an entry area are detected according to the electric signals outputted from the light-receiving elements, and coordinates of the light-blocked position are computed using the detected dark points in order to identify the coordinates of the light-blocked position. Herein, coordinates of the light-blocked position can be identified using, for example, the principle of triangulation. In the present invention, dark points generated on the light-receiving elements due blocking of the light beam in the entry area are detected according to the electric signals outputted from the light-receiving elements, coordinate information obtained by previously correlating the coordinates within the entry area to each combination of two detected dark points is referred to, and the coordinate values corresponding to the combination of the detected dark points are selected as coordinate values of the light-blocked position in order to identify the coordinates of the light-blocked position. In the present invention, a light emitting unit, a reflecting unit, and an intensity-distribution detecting unit are integrated with the frame, which enables easy attachment of the coordinate-position inputting/detecting device, for example, to a display unit. In the present invention, a minimum-value identifying unit identifies minimum values of the distribution of intensity detected by each intensity-distribution detecting unit respectively, a computing unit computes a time differentiation of identified coordinates. A determining unit determines contents of an input operation performed by a user in the entry area from the previously prepared condition and at least one of the minimum values, coordinate values, and time-differentiated values. In the present invention, an intensity-value identifying unit identifies the light intensity values of the dark points detected by a dark point detecting unit according to electric signals outputted from each of the light-receiving elements. A second computing unit computes the time differentiation of the coordinates obtained by the first computing unit. A determining unit determines contents of an input operation performed by a user in the entry area from the previously prepared condition and at least one of the light intensity values, coordinate values, and time-differentiated values. In the present invention, an intensity-value identifying unit identifies the light intensity values of the dark points detected by a dark point detecting unit according to electric signals outputted from each of the light-receiving elements. A first computing unit computes the time differentiation of the coordinates selected by the selecting unit. A determining unit determines the contents of an input operation performed by a user in the entry area from to the previously prepared condition and at least one of the light intensity values, coordinate values, and time-differentiated values. In the present invention, by using a result of previous determination concerning the contents of an operation as one of the conditions for determining the contents of the next operation, the contents of continuous input operation by a user can accurately be determined. In the present invention, by forming an entry area that matches with the size of a display surface of a display unit, the display surface can effectively be used. As the entry area is formed with light, viewability of the display unit is not reduced. In the present invention, by forming an entry area that matches with the size of a write-in surface for writing freehand characters and graphics, the write-in surface can effectively be used. As the entry area is formed with light, the write-in surface can be made use of as it is. In the present invention, the coordinate-position inputting/detecting device is provided in the front surface of a display unit for displaying characters and images, and a display surface and a write-in surface of a display board are formed with the display unit and coordinate-position inputting/detecting device, so that viewability of the display unit and operability of the system can be improved. In the present invention, the coordinate-position inputting/detecting device is provided in the front surface of a display unit for displaying thereon characters and images. As a result, a display surface and a write-in surface of the display board are formed with the display unit and coordinate-position inputting/detecting device, so that viewability of the display unit and operability of the system can be improved. Furthermore, the display board system comprises a frame unit having a holding section for holding a display surface and a write-in surface of the display board at a specified height, a printer accommodating section for accommodating the printer therein, and a control unit accommodating section for accommodating the control unit therein. The control unit accommodating section, printer accommodating section, and holding section are arranged in the vertical direction in this order from the bottom. As a result, transport and installation of the system can easily be carried out. In the present invention, by using a plasma display as a display unit, optimizations of the display board system can be performed. Namely, use of the plasma display allows the thickness of a display unit to be reduced, and also has high brightness as well as a wide viewing angle, and can reproduce moving pictures smoothly, so that the plasma display is preferable as a display unit of the display board system. In the present invention, a keyboard placement section for placing a keyboard connected to a personal computer is provided at a position in the upper side of the printer accommodating section and in the lower side of the holding section. Therefore, handling capability of the system is improved. In the present invention, an angle adjusting unit for adjusting an angle of a display surface and a write-in surface of the display board is provided in a holding section. Therefore, disturbance light coming into the display unit (display surface), especially, light from lighting equipment such as a fluorescent tube on the ceiling can be prevented. In the present invention, a plurality of connecting terminals for connecting various types of information equipment and AV equipment such as a digital camera, a DVD player, and video equipment are provided in a display unit and is usable as a large-sized screen monitor. Therefore, the display board system can be used in any occasions. Other objects and features of this invention will become understood from the following description with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view showing general configuration of a coordinate-position inputting/detecting device according to Embodiment 1 of the present invention; FIG. 2 shows general configuration of a light receiving/emitting device shown in FIG. 1; FIG. 3 shows another general configuration of the light receiving/emitting device shown in FIG. 1; FIG. 4 is a block diagram of a controller of the coordinate-position inputting/detecting device according to Embodiment 1 of the present invention; FIG. 5 explains the processing executed by the controller shown in FIG. 4; FIG. 6 explains a peak point detected through the processing executed by the controller shown in FIG. 4; FIG. 7 explains the operation of the coordinate-position inputting/detecting device as a whole according to Embodiment 1 of the present invention; FIG. 8 shows a modification in the configuration of the coordinate-position inputting/detecting device according to Embodiment 1 of the present invention; FIGS. 9A and 9B show general configuration of a light converging system shown in FIG. 8; FIG. 10 is a block diagram of a controller of a coordinate-position inputting/detecting device according to Embodiment 2 of the present invention; FIG. 11 shows the processing executed by the controller shown in FIG. 10; FIG. 12 explains a memory table stored in a ROM constituting the controller shown in FIG. 10; FIG. 13 is a block diagram of a controller of a coordinate-position inputting/detecting device according to Embodiment 3 of the present invention; FIGS. 14A to FIG. 14C are explanatory views, in the coordinate-position inputting/detecting device according to Embodiment 3 of the present invention, each showing a relation between a position of a pointing body in the Z-axial direction and probe light blocked by the pointing body when an arbitrary position in a coordinate-position entry area is pointed with the pointing body, and also showing information for distribution of intensity obtained by the position of the pointing body in the Z-axial direction and a light-receiving element; FIG. 15 explains the state shifting rule used for deciding the state of a pointing body by the controller of the coordinate-position inputting/detecting device according to Embodiment 3 of the present invention; FIG. 16 shows a state table used for deciding the state of a pointing body by the controller of the coordinate-position inputting/detecting device according to Embodiment 3 of the present invention; FIG. 17 shows another example of the state table used for deciding the state of a pointing body by the controller of the coordinate-position inputting/detecting device according to Embodiment 3 of the present invention; FIG. 18 shows a general configuration of another coordinate-position inputting/detecting device in which the controller according to Embodiment 3 of the present invention is applicable; FIG. 19 shows a general configuration of still another coordinate-position inputting/detecting device in which the controller according to Embodiment 3 of the present invention is applicable; FIG. 20 shows a general configuration of still another coordinate-position inputting/detecting device in which the controller according to Embodiment 3 of the present invention is applicable; FIG. 21 is a block diagram of a display board according to Embodiment 4 of the present invention; FIG. 22 is a block diagram of a computer (personal computer) of a display board system according to Embodiment 4 of the present invention; FIG. 23 is a perspective front view of a frame unit with the display board system according to Embodiment 4 of the present invention accommodated therein; FIG. 24 is a perspective rear view of the frame unit with the display board system according to Embodiment 4 of the present invention accommodated therein; FIG. 25 is a side view of the frame unit according to Embodiment 4 of the present invention viewed from the right side thereof; FIG. 26 shows the configuration of an angle adjusting mechanism section according to Embodiment 4 of the present invention viewed from the upper side of the frame unit (angle of the board section is five degrees); FIG. 27 shows the configuration of the angle adjusting mechanism section according to Embodiment 4 of the present invention viewed from the upper side of the frame unit (angle of the board section is zero degree); FIG. 28 shows the configuration of the angle adjusting mechanism section according to Embodiment 4 of the present invention viewed from the side of the frame unit; FIG. 29 shows modification of the angle adjusting mechanism section according to Embodiment 4 of the present invention; FIG. 30 shows another modification of the angle adjusting mechanism section according to Embodiment 4 of the present invention; FIG. 31 shows an example of the screen of the display board and a toolbar displayed on the PDP in the display board system according to Embodiment 4 of the present invention; FIG. 32 shows an example of an extension toolbar displayed on the PDP in the display board system according to Embodiment 4 of the present invention; FIG. 33 shows an example of a drawing toolbar together with the extension toolbar displayed on the PDP in the display board system according to Embodiment 4 of the present invention; FIG. 34 shows an example of how a result of freehand characters and lines on the touch surface is displayed on the screen of the display board on the PDP in the display board system according to Embodiment 4 of the present invention; FIG. 35 shows an example of how the freehand characters and lines displayed on the screen of the display board are deleted with an eraser in the display board system according to Embodiment 4 of the present invention; FIG. 36 shows an example of how the freehand characters and lines displayed on the screen of the display board are enclosed with a box and the characters and lines in the box are deleted in one operation in the display board system according to Embodiment 4 of the present invention; FIG. 37 shows a line drawn on the screen of the display board in the display board system according to Embodiment 4 of the present invention; FIG. 38 shows a rectangle drawn on the screen of the display board in the display board system according to Embodiment 4 of the present invention; FIG. 39 shows a grid pattern displayed as a background of the screen of the display board in the display board system according to Embodiment 4 of the present invention; FIG. 40 shows a table created on the screen of the display board in the display board system according to Embodiment 4 of the present invention; FIG. 41 shows an ellipse created on the screen of the display board in the display board system according to Embodiment 4 of the present invention; FIG. 42A explains selection of a graphics as an object for modification and FIG. 42B shows the graphics after its modification in the display board system according to Embodiment 4 of the present invention; FIG. 43A shows selection of a graphics as an object to be moved and FIG. 43B shows the graphics after its movement in the display board system according to Embodiment 4 of the present invention; FIG. 44 shows an example of a edit menu displayed when an already created graphics is to be edited in the display board system according to Embodiment 4 of the present invention; FIG. 45 explains the processing for opening an already generated file in the display board system according to Embodiment 4 of the present invention; FIG. 46 explains the processing for opening an already generated file using thumbnail images in the display board system according to Embodiment 4 of the present invention; FIG. 47 shows an example of a screen of the computer and a capture toolbar displayed on the PDP in the display board system according to Embodiment 4 of the present invention; FIG. 48 explains an example of how a screen of a captured application program is displayed as a background of the screen of the display board in the display board system according to Embodiment 4 of the present invention; FIG. 49 explains an example of how a screen of a captured application program is displayed as a background of the screen of the display board and how the characters or the like are written on the screen in the display board system according to Embodiment 4 of the present invention; FIG. 50 shows how a thumbnail display dialog box for displaying the pages in creation in a list form is displayed in the display board system according to Embodiment 4 of the present invention; FIG. 51 shows how a printing dialog box for printing the pages in creation is displayed in the display board system according to Embodiment 4 of the present invention; FIG. 52 shows an example of a setting screen for coordinate-position input device in the display board system according to Embodiment 4 of the present invention; FIG. 53 explains the network connection of the display board system according to Embodiment 4 of the present invention; FIG. 54 shows the configuration of a display unit of a display board system according to Embodiment 5 of the present invention; FIG. 55 is a block diagram showing a main control section of the display board system according to Embodiment 5 of the present invention; FIG. 56 shows a screen that displays a point-operation area in the display board system according to Embodiment 5 of the present invention; FIG. 57 is a flow chart of a point operation in the display board system according to Embodiment 5 of the present invention; FIGS. 58A, 58B and 58C are processing steps showing display and deletion of a point-operation area in the display board system according to Embodiment 5 of the present invention; FIG. 59 is a flow chart of the processing for display and deletion of a point-operation area in the display board system according to Embodiment 5 of the present invention; FIG. 60 is an explanatory view that shows display contents on the display screen appearing within the point-operation area in the display board system according to Embodiment 5 of the present invention; FIG. 61 explains a moving operation of the points in association with transformation of coordinates in the display board system according to Embodiment 5 of the present invention; FIG. 62 is a time chart showing drag operations according to operations within a point-operation area in the display board system according to Embodiment 5 of the present invention; FIG. 63 is a block diagram showing a first example of the configuration of a display board system according to Embodiment 6 of the present invention; FIG. 64 is an appearance view of the first example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 65 explains an example of a method of detecting a position of a person from an image based on the first example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 66 explains a method of deciding a position where a ten-key is to be displayed in the display board system according to Embodiment 6 of the present invention; FIG. 67 is a block diagram showing a second example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 68 is an appearance view showing the second example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 69 is a block diagram showing a third example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 70 is an appearance view showing the third example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 71 is a block diagram showing a fourth example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 72 is an appearance view showing the fourth example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 73 is a block diagram showing a fifth example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 74 is an appearance view showing the fifth example of the configuration of the display board system according to Embodiment 6 of the present invention; FIG. 75 is a block diagram showing configuration, for displaying an input window (a ten-key display specifying window) to specify a position where a ten-key is displayed on an entry screen, applicable in the display board system according to Embodiment 6 of the present invention; FIG. 76 is a block diagram showing hardware configuration of the display board system according to Embodiment 6 of the present invention; FIG. 77 is a block diagram showing a first example of the configuration of a display board system according to Embodiment 7 of the present invention; FIG. 78 shows a waveform outputted from a coordinate-position input device in the first example of the configuration of the display board system according to Embodiment 7 of the present invention; FIG. 79 is a flow chart of operations of the first example of the configuration of the display board system according to Embodiment 7 of the present invention; FIG. 80 is a block diagram showing a second example of the configuration of the display board system according to Embodiment 7 of the present invention; FIG. 81 is a flow chart of operations of the second example of the configuration of the display board system according to Embodiment 7 of the present invention; FIG. 82 is a block diagram showing a third example of the configuration of the display board system according to Embodiment 7 of the present invention; FIG. 83 is a flow chart of operations of the third example of the configuration of the display board system according to Embodiment 7 of the present invention; FIG. 84 is a block diagram showing a fourth example of the configuration of the display board system according to Embodiment 7 of the present invention; and FIG. 85 is a block diagram showing a fifth example of the configuration of the display board system according to Embodiment 7 of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Detailed description is made hereinafter for embodiments of the a method and device for inputting/detecting the coordinate position according to the present invention and a display board system using the same with reference to the attached drawings. FIG. 1 is a front view showing general configuration of a coordinate-position inputting/detecting device according to Embodiment 1 of the present invention. The coordinate-position inputting/detecting device 1 according to Embodiment 1 is connected to a computer such as a personal computer and a work station. The coordinate-position inputting/detecting device is utilized by attaching it to the front surface of the display of the computer. In the figure, the reference numeral d indicates a display of the Computer. As shown in FIG. 1, the coordinate-position inputting/detecting device 1 comprises a frame 1a for defining an entry area 2 for inputting coordinate values such that freehand characters and graphics are inputted corresponding to a size of the display d. Light emitting/receiving devices 3L and 3R provided at both edge sections in the lower side of the frame 1a. The light emitting/receiving devices 3L and 3R emit fan-shaped light so as to cover the whole area of the entry area 2 and also receive the light reflected by a recursively reflecting member 4 provided in the peripheral section of the frame 1a excluding the lower side thereof. A controller (Refer to FIG. 4 and FIG. 5) not shown herein for executing the processing of identifying a positio |