Coordinate input apparatus and coordinate input method

• US 7,375,720 B2
• Filed: 08/04/2004
• Issued: 05/20/2008
• Est. Priority Date: 08/07/2003
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tanaka, Atsushi
• Primary Examiner(s): Shalwala; Bipin
• Assistant Examiner(s): Chowdhury; Afroza Y
• Application Number:
  US10/910,270
• Publication Number:
  US 20050041013A1
• Time in Patent Office: 1,385 Days
• Field of Search: 345179-184
• US Class Current: 345/156
• CPC Class Codes: G02B 5/124 plural reflecting elements forming part of a unitary plate or sheet
• CPC Class Codes: G06F 3/0325 using a plurality of light emitters or reflectors or a plurality of detectors forming a reference frame from which to derive the orientation of the object, e.g. by triangulation or on the basis of reference deformation in the picked up image
• CPC Class Codes: G06F 3/0428 by sensing at the edges of the touch surface the interruption of optical paths, e.g. an illumination plane, parallel to the touch surface which may be virtual sensing beam interruptions in a planar beam grid of an optical touch-screen G06F3/0421

Abstract

In a coordinate input apparatus including the detection unit of a sensor unit (1R, 1L) arranged at a corner of a coordinate input region (4), a retroreflecting member (3) arranged at the peripheral portion of the coordinate input region (4) to retroreflect incident light, the light projecting unit of the sensor unit (1R, 1L) which projects light to the coordinate input region (4), and a control/arithmetic unit (2) which executes a coordinate acquisition operation for obtaining the coordinate position of a pointer (6) having a light-emitting function in the coordinate input region (4) on the basis of a light amount distribution obtained from the detection unit of the sensor unit (1R, 1L), a light-receiving IC (5) detects a light emission signal from the pointer (6), and the control/arithmetic unit 2 controls the coordinate acquisition operation on the basis of the detection result.

Claims

1. A coordinate input apparatus including light-emitting means for projecting light to a coordinate input region, reflection means arranged at a peripheral portion of the coordinate input region, for recursively reflecting light emitted from said light-emitting means, light-receiving means arranged in the coordinate input region, for receiving light reflected by said reflection means, and calculation means for executing a coordinate acquisition operation for obtaining a position where light is shielded in the coordinate input region as a coordinate position of a pointer having a light-emitting function in the coordinate input region, on the basis of a light amount distribution obtained from said light-receiving means, comprising:

detection means for detecting, as a light emission signal, light emitted from the pointer; and

control means for controlling the coordinate acquisition operation by said calculation means on the basis of a detection result by said detection means,

wherein said control means controls to inhibit said calculation means from executing the coordinate acquisition operation during a predetermined period after said detection means detects the light emission signal transmitted from the pointer.

2. The apparatus according to claim 1, wherein said control means controls to inhibit the light-emitting means from projecting light during a predetermined period after said detection means detects the light emission signal from the pointer.

3. The apparatus according to claim 1, wherein a length of the predetermined period is longer than the period when said light-emitting means projects light for coordinate detection of the pointer.

4. The apparatus according to claim 1, wherein said control means controls to inhibit the calculation means from executing the coordinate acquisition operation during only a predetermined period from a start of light emission by the light-emitting means and during only a predetermined period from an end of light emission.

5. The apparatus according to claim 1, wherein the pointer emits light to a side of the light-receiving means.

6. The apparatus according to claim 1, further comprising display means, said display means being superposed on the coordinate input region.

7. A coordinate input method of a coordinate input apparatus including light-emitting means for projecting light to a coordinate input region, reflection means arranged at a peripheral portion of the coordinate input region, for recursively reflecting light emitted from said light-emitting means, light-receiving means arranged in the coordinate input region, for receiving light reflected by said reflection means, and calculation means for executing a coordinate acquisition operation for obtaining a position where light is shielded in the coordinate input region as a coordinate position of a pointer having a light-emitting function in the coordinate input region, on the basis of a light amount distribution obtained from said light-receiving means, the method comprising:

a detection step of detecting, as a light emission signal, light emitted from the pointer; and

a control step of controlling the coordinate acquisition operation by said calculation means on the basis of a detection result in the detection step,

wherein said control step controls to inhibit said calculation means from executing the coordinate acquisition operation during a predetermined period after said detection step detects the light emission signal transmitted from the pointer.

8. A computer-executable program, stored on a computer-readable storage medium, for causing a computer to execute a coordinate input method of claim 7.

9. A computer-readable storage medium which stores a program of claim 8.