Method and apparatus for coordinate inputting capable of effectively using a laser ray

• US 6,570,103 B1
• Filed: 09/05/2000
• Issued: 05/27/2003
• Est. Priority Date: 09/03/1999
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Saka, Yasuhiko, Takekawa, Kenichi
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): Kovalick, Vincent E.
• Application Number:
  US09/655,776
• Time in Patent Office: 994 Days
• Field of Search: 345/156, 345/158, 345/162, 345/166, 345/173, 345/178, 345/204, 345/207, 178/180.01, 178/18.03, 178/18-4-, 178/19.01, 178/19.02, 178/19.03, 250/216, 250/222.1, 250/227.11, 250/227.16, 340/555, 340/556, 340/557, 341/5
• US Class Current: 178/18.01
• 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

Abstract

A coordinate input apparatus includes light sources, a reflecting member, light receiving members, a signal analyzing mechanism, and a coordinate determining mechanism. Each light source is fixed around a perimeter of a predefined input region at a fixing position different from others and is configured to emit light extending in a deltaic form centered at the fixing position and approximately in parallel to the input region. The reflecting member is fixed around the perimeter of the input region and is configured to recursively reflect the light so that the light returns towards the light sources. The light receiving members are fixed around the perimeter of the input region and are configured to receive the light recursively reflected from the reflecting member and to convert the light into an electric signal. The signal analyzing mechanism analyzes the electric signal to detect a position of an obstacle when the obstacle is placed in the input region and blocks the light. The coordinate determining mechanism calculates a center between coordinates of one and the other edges of the obstacle and determines the center as a coordinate of the position of the obstacle in the input region.

Claims

1. A coordinate input apparatus, comprising:

a plurality of light sources, each light source being fixed around a perimeter of a predefined input region at a fixing position different from others of the light sources and configured to emit light approximately in parallel to said predefined input region;

a reflecting member fixed around said perimeter of said predefined input region and configured to recursively reflect said light so that said light returns towards said plurality of light sources;

a plurality of light receiving members fixed around said perimeter of said predefined input region and configured to receive said light recursively reflected from said reflecting member and to convert said light into electric signals;

a signal analyzing mechanism configured to analyze said electric signals to detect a position of an obstacle when said obstacle is placed in said input region and blocks said light output from said plurality of light sources; and

a coordinate determining mechanism configured to calculate a center between coordinates of edges of said obstacle and to determine said center as a coordinate of said position of said obstacle in said input region based on a plurality of successively-aligned pixels in said electric signals, including at least a focus pixel and pixels immediately previous to and subsequent to said focus pixel.

2. A coordinate input apparatus as defined in claim 1, wherein the emitted light from said plurality of light sources extends in a deltaic form centered at said fixing position.

3. A coordinate input apparatus, comprising:

a plurality of light sources, each light source being fixed around a perimeter of a predefined input region at a fixing position different from others of the light sources and configured to emit light and approximately in parallel to said predefined input region;

a reflecting member fixed around said perimeter of said predefined input region and configured to recursively reflect said light so that said light returns towards said plurality of light sources;

a plurality of light receiving members fixed around said perimeter of said predefined input region and configured to receive said light recursively reflected from said reflecting member and to convert said light into electric signals;

a signal analyzing mechanism configured to analyze said electric signals to detect a position of an obstacle when said obstacle is placed in said input region and blocks said light output from said plurality of light sources;

a memory configured to prestore a first light amount reference value and a second light amount reference value having a value greater than that of said first light amount reference value; and

a coordinate determining mechanism configured to determine a coordinate of said position of said obstacle placed in said input region based on a plurality of successively-aligned pixels in said electric signals, including at least a focus pixel and pixels immediately previous to and immediately subsequent to said focus pixel, and said first and second light amount reference values such that;

when each of said immediately previous, focus, and immediately subsequent pixels has a brighter value than that of said second light amount reference value, a coordinate of said focus pixel is determined as not a coordinate of an edge of said obstacle;

when each of said immediately previous and focus pixels has a brighter value than that of said second light amount reference value and said immediately subsequent pixel has a darker value than those of said first and second light amount reference values, the coordinate of said focus pixel is determined as not a coordinate of an edge of said obstacle;

when said immediately previous pixel has a brighter value than that of said second light amount reference value, when the focus pixel has a darker value than that of said second light amount reference value, and when said immediately subsequent pixel has a darker value than those of said first and second light amount reference values, the coordinate of said focus pixel is determined as a coordinate between a center and a right edge of said obstacle;

when said immediately previous pixel has a brighter value than that of said second light amount reference value, when said focus pixel has a darker value than that of said first light amount reference value, and when said immediately subsequent pixel has a darker value than those of said first and second light amount reference values, the coordinate of said focus pixel is determined as a coordinate of the center of said obstacle;

when said immediately previous pixel has a darker value than those of said first and second light amount reference values, and when each of said focus and immediately subsequent pixels has a brighter value than that of said second light amount reference value, the coordinate of said focus pixel is determined as not the coordinate of the center of said obstacle;

when said immediately previous pixel has a darker value than those of said first and second light amount reference values, when said focus pixel has a darker value than that of said second light amount reference value, and when said immediately subsequent pixel has a brighter value than that of said second light amount reference value, the coordinate of said focus pixel is determined as a coordinate between a left edge and the center of said obstacle;

when said immediately previous pixel has a darker value than those of said first and second light amount reference values, when said focus pixel has a darker value than that of aid first light amount reference value, and when said immediately subsequent pixel has a brighter value than that of said second light amount reference value, the coordinate of said focus pixel is determined as the coordinate of the center of said obstacle; and

when each of said immediately previous, focus, and immediately subsequent pixels has a darker value than those of said first and second light amount reference values, the coordinate of said focus pixel is determined as not a coordinate of an edge of said obstacle.

4. A coordinate input apparatus as defined in claim 3, wherein the emitted light from said plurality of light sources extends in a deltaic form centered at said fixing position.

5. A coordinate input apparatus, comprising:

a plurality of light sources, each light source being fixed around a perimeter of a predefined input region at a fixing position different from others of the light sources and configured to emit light approximately in parallel to said predefined input region;

a reflecting member fixed around said perimeter of said predefined input region and configured to recursively reflect said light so that said light returns towards said plurality of light sources;

a plurality of light receiving members fixed around said perimeter of said predefined input region, configured to receive said light recursively reflected from said reflecting member and to convert said light into electric signals, and each of said plurality of light receiving members including a photoelectric conversion cell array including a plurality of photoelectric conversion cells placed in a line for receiving said light reflected from said reflecting member, an order of said plurality of said photoelectric conversion cells placed in the line corresponding to coordinates of said input region;

a signal analyzing mechanism configured to analyze said electric signals to detect a position of an obstacle when said obstacle is placed in said input region and blocks the light output from said plurality of light sources; and

a coordinate determining mechanism configured to determine a coordinate of said position of said obstacle placed in said input region based on a result of an analysis made by said signal analyzing mechanism and based on a plurality of successively-aligned pixels in said electric signals, including at least a focus pixel and pixels immediately previous to and subsequent to said focus pixel.

6. A coordinate input apparatus as defined in claim 5, wherein the emitted light from said plurality of light sources extends in a deltaic form centered at said fixing position.

7. A coordinate input apparatus as defined in claim 5, wherein each photoelectric conversion cell array includes a charge-coupled device.

8. A coordinate input apparatus as defined in claim 5, wherein each photoelectric conversion cell array includes a phototransistor array.

9. A coordinate input apparatus as defined in claim 5, wherein each photoelectric conversion cell array includes a photodiode array.

10. A coordinate input apparatus as defined in claim 5, further comprising a correcting mechanism configured to correct said electric signals respectively output from each of said light receiving members for an angle displacement of each of said plurality of light receiving members.

11. A coordinate input apparatus as defined in claim 5, further comprising a correcting mechanism configured to correct said electric signals respectively output from each of said light receiving members for a position displacement of each of said plurality of light receiving members.

12. A method for coordinate input, comprising the steps of:

providing a plurality of light sources, each light source being fixed around a perimeter of a predefined input region at a fixing position different from others of the light sources;

causing said plurality of light source to emit light approximately in parallel to said predefined input region;

reflecting said light recursively around said perimeter of said predefined input region;

receiving said light reflected by said reflecting step by a plurality of light receiving members fixed around said perimeter of said predefined input region;

converting said light received by said reflecting step into electric signals;

analyzing said electric signals to detect a position of an obstacle when said obstacles is placed in said input region and blocks the light output from said plurality of light sources;

calculating a center between coordinates of edges of said obstacle; and

determining said center as a coordinate of said position of said obstacle in said input region base on a plurality of successively-aligned pixels in said electric signals, including at least a focus pixel and pixels immediately previous to and subsequent to said focus pixel.

13. A method for coordinate input as defined in claim 12, wherein the emitted light from said plurality of light sources extends in a deltaic form centered at said fixing position.

14. A method for coordinate input, comprising the steps of:

prestoring into a memory a first light amount reference value and a second light amount reference value having a value greater than that of said first light amount reference value;

providing a plurality of light sources, each light source being fixed around a perimeter of a predefined input region at a fixing position different from others of the light sources;

causing said plurality of light sources to emit light approximately in parallel to said predefined input region;

reflecting said light recursively around said perimeter of said predefined input region;

receiving said light reflected by said reflecting step by a plurality of light receiving members fixed around said perimeter of said predefined input region;

converting said light received by said reflecting step into electric signals;

analyzing said electric signals to detect a position of an obstacle when said obstacle is placed in said input region and blocks the light output from said plurality of light sources; and

determining a coordinate of said position of said obstacle placed in said input region based on a plurality of successively-aligned pixels in said electric signal, including at least a focus pixel and pixels immediately previous to and immediately subsequent to said focus pixel, and said first and second light amount reference values such that;

when each of said immediately previous, focus, and immediately subsequent pixels has a brighter value than that of said second light amount reference value, a coordinate of said focus pixel is determined as not a coordinate of an edge of said obstacle;

when each of said immediately previous and focus pixels has a brighter value than that of said second light amount reference value and said immediately subsequent pixel has a darker value than those of said first and second light amount reference values, the coordinate of said focus pixel is determined as not a coordinate of an edge of said obstacle;

when said immediately previous pixel has a brighter value than that of said second light amount reference value, when the focus pixel has a darker value than that of said second light amount reference value, and when said immediately subsequent pixel has a darker value than those of said first and second light amount reference values, the coordinate of said focus pixel is determined as a coordinate between a center and a right edge of said obstacle;

when said immediately previous pixel has a brighter value than that of said second light amount reference value, when said focus pixel has a darker value than that of said first light amount reference value, and when said immediately subsequent pixel has a darker value than those of said first and second light amount reference values, the coordinate of said focus pixel is determined as a coordinate of the center of said obstacle;

when said immediately previous pixel has a darker value than those of said first and second light amount reference values and when each of said focus and immediately subsequent pixels has a brighter value than that of said second light amount reference value, the coordinate of said focus pixel is determined as not the coordinate of the center of said obstacle;

when said immediately previous pixel has a darker value than those of said first and second light amount reference values, when said focus pixel has a darker value than that of said second light amount reference value, and when said immediately subsequent pixel has a brighter value than that of said second light amount reference value, the coordinate of said focus pixel is determined as a coordinate between a left edge and the center of said obstacle;

when said immediately previous pixel has a darker value than those of said first and second light amount reference values, when said focus pixel has a darker value than that of said first light amount reference value, and when said immediately subsequent pixel has a brighter value than that of said second light amount reference value, the coordinate of said focus pixel is determined as the coordinate of the center of said obstacle; and

when each of said immediately previous, focus, and immediately subsequent pixels has a darker value than those of said first and second light amount reference values, the coordinate of said focus pixel is determined as not a coordinate of an edge of said obstacle.

15. A method for coordinate input as defined in claim 14, wherein the emitted light from said plurality of light sources extends in a deltaic form centered at said fixing position.

16. A coordinate input apparatus, comprising:

a touch-panel;

a plurality of light sources, each light source being fixed around a perimeter of said touch-panel at a fixing position different from others of the light sources and configured to emit light approximately in parallel to said touch-panel;

a reflecting member fixed around said perimeter of said touch-panel and configured to recursively reflect said light so that said light returns towards said plurality of light sources;

a plurality of light receiving members fixed around said perimeter of said touch-panel and configured to receive said light recursively reflected from said reflecting member and to convert said light into electric signals, said plurality of light receiving members being integral with said plurality of light sources;

a signal analyzing mechanism configured to analyze said electric signals to detect a position of an obstacle when said obstacle is placed on said touch-panel and blocks the light output from said plurality of light sources;

a coordinate calculating mechanism configured to execute an approximate equation configured to subtract variations of said light amount from coordinates respectively close to coordinates of edges of said obstacle in order to obtain coordinates in accordance with a light amount reference value, and to output said coordinates obtained through said approximate equation as true coordinates of the edges of said obstacle; and

a coordinate determining mechanism configured to calculate a center between said true coordinates of the edges of said obstacle and to determine said center calculated as a coordinate of said position of said obstacle placed in said touch-panel, wherein said coordinate calculating mechanism executes said approximate equation using a first pixel with a light amount value which exceeds that of said light amount reference value, and light amounts of pixels immediately previous to and immediately subsequent to said first exceeding pixel.

17. A coordinate input apparatus as defined in claim 16, wherein the emitted light from said plurality of light sources extends in a deltaic form centered at said fixing position.

18. A coordinate input apparatus, comprising:

a touch-panel;

a plurality of light sources, each light source being fixed around a perimeter of said touch-panel at a fixing position different from others of the light sources and configured to emit light approximately in parallel to said touch-panel;

a reflecting member fixed around said perimeter of said touch-panel and configured to recursively reflect said light so that said light returns towards said plurality of light sources;

a plurality of light receiving members fixed around said perimeter of said touch-panel and configured to receive said light recursively reflected from said reflecting member and to convert said light into electric signals, said plurality of light receiving members being integral with said plurality of light sources;

a signal analyzing mechanism configured to analyze said electric signals to detect a position of an obstacle when said obstacle is placed on said touch-panel and blocks the light output from said plurality of light sources;

a coordinate calculating mechanism configured to calculate a center between coordinates of edges of said obstacle; and

a coordinate determining mechanism configured to determine a coordinate X of said position of said obstacle by executing equation

19. A coordinate input apparatus as defined in claim 18, wherein the emitted light from said plurality of light sources extends in a deltaic form centered at said fixing position.

20. A coordinate input apparatus, comprising:

a plurality of light source means fixed around a perimeter of a predefined input region for emitting light approximately in parallel to said predefined input region;

reflecting means for recursively reflecting said light from said perimeter of said predefined input region so that said light returns towards said plurality of light source means;

light receiving means for receiving said light recursively reflected from said reflecting means and for converting said light into electric signals;

signal analyzing means for analyzing said electric signals to detect a position of an obstacle when said obstacle is placed in said input region and blocks said light output from said plurality of light source means; and

a coordinate determining means for calculating a center between coordinates of edges of said obstacle and for determining said center as a coordinate of said position of said obstacle in said input region based on a plurality of successively-aligned pixels in said electric signals, including at least a focus pixel and pixels immediately previous to and subsequent to said focus pixel.

21. A coordinate input apparatus as defined in claim 20, further comprising correcting means for correcting said electric signals respectively output from said light receiving means for an angle displacement of said light receiving means.

22. A coordinate input apparatus as defined in claim 20, further comprising correcting means for correcting said electric signals respectively output from said light receiving means for a position displacement of said light receiving means.

23. A coordinate input apparatus, comprising:

a plurality of light sources, each light source being fixed around a perimeter of a predefined input region at a fixing position different from others of the light sources and configured to emit light approximately in parallel to said predefined input region;

a reflecting member fixed around said perimeter of said predefined input region and configured to recursively reflect said light so that said light returns towards said plurality of light sources;

a plurality of light receiving members fixed around said perimeter of said predefined input region, configured to receive said light recursively reflected from said reflecting member and to convert said light into electric signals, and each of said plurality of light receiving members including a photoelectric conversion cell array including a plurality of photoelectric conversion cells placed in a line for receiving said light reflected from said reflecting member, an order of said plurality of said photoelectric conversion cells placed in the line corresponding to coordinates of said input region;

a signal analyzing mechanism configured to analyze said electric signals to detect a position of an obstacle when said obstacle is placed in said input region and blocks the light output from said plurality of light sources;

a coordinate determining mechanism configured to determine a coordinate of said position of said obstacle placed in said input region based on a result of an analysis made by said signal analyzing mechanism; and

a correcting mechanism configured to correct said electric signals respectively output from each of said light receiving members for an angle displacement of each of said plurality of light receiving members.

24. A coordinate input apparatus as defined in claim 23, wherein the emitted light from said plurality of light sources extends in a deltaic form centered at said fixing position.

25. A coordinate input apparatus as defined in claim 23, wherein each photoelectric conversion cell array includes a charge-coupled device.

26. A coordinate input apparatus as defined in claim 23, wherein each photoelectric conversion cell array includes a phototransistor array.

27. A coordinate input apparatus as defined in claim 23, wherein each photoelectric conversion cell array includes a photodiode array.

28. A coordinate input apparatus, comprising:

a plurality of light sources, each light source being fixed around a perimeter of a predefined input region at a fixing position different from others of the light sources and configured to emit light approximately in parallel to said predefined input region;

a reflecting member fixed around said perimeter of said predefined input region and configured to recursively reflect said light so that said light returns towards said plurality of light sources;

a plurality of light receiving members fixed around said perimeter of said predefined input region, configured to receive said light recursively reflected from said reflecting member and to convert said light into electric signals, and each of said plurality of light receiving members including a photoelectric conversion cell array including a plurality of photoelectric conversion cells placed in a line for receiving said light reflected from said reflecting member, an order of said plurality of said photoelectric conversion cells placed in the line corresponding to coordinates of said input region;

a signal analyzing mechanism configured to analyze said electric signals to detect a position of an obstacle when said obstacle is placed in said input region and blocks the light output from said plurality of light sources;

a coordinate determining mechanism configured to determine a coordinate of said position of said obstacle placed in said input region based on a result of an analysis made by said signal analyzing mechanism; and

a correcting mechanism configured to correct said electric signals respectively output from each of said light receiving members for a position displacement of each of said plurality of light receiving members.

29. A coordinate input apparatus as defined in claim 28, wherein the emitted light from said plurality of light sources extends in a deltaic form centered at said fixing position.

30. A coordinate input apparatus as defined in claim 28, wherein each photoelectric conversion cell array includes a charge-coupled device.

31. A coordinate input apparatus as defined in claim 28, wherein each photoelectric conversion cell array includes a phototransistor array.

32. A coordinate input apparatus as defined in claim 28, wherein each photoelectric conversion cell array includes a photodiode array.

33. A coordinate input apparatus comprising:

a plurality of light source means fixed around a perimeter of a predefined input region for emitting light approximately in parallel to said predefined input region;

reflecting means for recursively reflecting said light from said perimeter of said predefined input region so that said light returns towards said plurality of light source means;

light receiving means for receiving said light recursively reflected from said reflecting means and for converting said light into electric signals;

signal analyzing means for analyzing said electric signals to detect a position of an obstacle when said obstacle is placed in said input region and blocks said light output from said plurality of light source means;

a coordinate determining means for calculating a center between coordinates of edges of said obstacle and for determining said center as a coordinate of said position of said obstacle in said input region; and

correcting means for correcting said electric signals respectively output from said light receiving means for an angle displacement of said light receiving means.

34. A coordinate input apparatus comprising:

a plurality of light source means fixed around a perimeter of a predefined input region for emitting light approximately in parallel to said predefined input region;

reflecting means for recursively reflecting said light from said perimeter of said predefined input region so that said light returns towards said plurality of light source means;

light receiving means for receiving said light recursively reflected from said reflecting means and for converting said light into electric signals;

signal analyzing means for analyzing said electric signals to detect a position of an obstacle when said obstacle is placed in said input region and blocks said light output from said plurality of light source means;

a coordinate determining means for calculating a center between coordinates of edges of said obstacle and for determining said center as a coordinate of said position of said obstacle in said input region; and

correcting means for correcting said electric signals respectively output from said light receiving means for a position displacement of said light receiving means.