Coordinate input apparatus

• US 6,710,767 B1
• Filed: 09/01/2000
• Issued: 03/23/2004
• Est. Priority Date: 09/06/1999
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tanaka, Atsushi, Kobayashi, Katsuyuki, Kobayashi, Kiwamu, Hasegawa, Masahide, Kanashiki, Masaaki, Yoshimura, Yuichiro
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): Kovalick, Vincent E.
• Application Number:
  US09/654,393
• Time in Patent Office: 1,299 Days
• Field of Search: 128/18.01, 128/18.09, 128/18.11, 128/19.05, 341/5, 345/157, 345/158, 345/166, 345/175, 345/179, 345/183, 345/180, 345/156, 356/141.2, 356/141.5, 356/375, 356/400
• US Class Current: 345/157
• CPC Class Codes: G06F 3/0386 for light pen
• CPC Class Codes: G06F 3/0425 using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected tracking a projected light spot to determine a position on a display surface G06F3/0386

Abstract

A first cylindrical lens and a first linear sensor are constructed on the X axis, a second cylindrical lens and a second linear sensor are constructed on the Y axis, the X and Y axes are orthogonal, and the image width of a beam spot formed by each of the first and second cylindrical lenses is larger than each pixel of the corresponding first and second linear sensors.

Claims

1. A coordinate input apparatus for generating coordinates corresponding to a light spot produced by a designating tool, comprising:

first image sensing means, which is constructed on a first coordinate axis by a first image-forming optical system and a first linear sensor, for sensing the light spot;

second image sensing means, which is constructed on a second coordinate axis by a second image-forming optical system and a second linear sensor, for sensing the light spot; and

light diffusing means for diffusing the image width of the light spot formed by each of said first and second image-forming optical systems;

wherein the first and second coordinate axes are orthogonal and an image width of the light spot formed by each of said first and second image-forming optical systems is diffused by the light diffusing means to several times the pixel pitch of the corresponding first and second linear sensors such that the light spot is sensed in several pixels of the first and second image sensing means.

2. The apparatus according to claim 1, further comprising adjustment means for adjusting the image width of the light spot formed by each of said first and second image-forming optical systems.

3. The apparatus according to claim 2, wherein said adjustment means is a light diffusing plate.

4. The apparatus according to claim 3, wherein said light diffusing plate is placed on the side of the coordinate input screen facing said image-forming optical systems.

5. The apparatus according to claim 3, wherein said light diffusing plate has wavelength-selective transmissivity.

6. The apparatus according to claim 3, wherein said light diffusing plate is constituted by an infrared transmitting filter and a light diffusing film.

7. The apparatus according to claim 3, wherein said light diffusing plate is bonded to said first and second linear sensors.