Coordinate position inputting/detecting device, a method for inputting/detecting the coordinate position, and a display board system

• US 6,429,856 B1
• Filed: 05/10/1999
• Issued: 08/06/2002
• Est. Priority Date: 05/11/1998
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Tanaka, Makoto, Tsuda, Kunikazu, Omura, Katsuyuki
• Primary Examiner(s): Liang, Regina
• Application Number:
  US09/307,809
• Time in Patent Office: 1,184 Days
• Field of Search: 345/173, 345/175-183, 178/18.01, 178/18.09, 178/18.03
• US Class Current: 345/175
• CPC Class Codes: G06F 21/31 User authentication
• CPC Class Codes: G06F 21/83 input devices, e.g. keyboards, mice or controllers thereof
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06F 3/0481 based on specific properties of the displayed interaction object or a metaphor-based environment, e.g. interaction with desktop elements like windows or icons, or assisted by a cursor's changing behaviour or appearance

Abstract

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.

Claims

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.