Coordinate input apparatus and its control method

• US 7,746,326 B2
• Filed: 07/13/2005
• Issued: 06/29/2010
• Est. Priority Date: 07/14/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sato, Hajime
• Primary Examiner(s): Mengistu; Amare
• Assistant Examiner(s): LAM, VINH TANG
• Application Number:
  US11/179,747
• Publication Number:
  US 20060012579A1
• Time in Patent Office: 1,812 Days
• Field of Search: 345/163, 345169-178, 345/179, 345/180, 345/182, 345/183, 178/18.01
• US Class Current: 345/173
• CPC Class Codes: G02B 5/124 plural reflecting elements forming part of a unitary plate or sheet
• CPC Class Codes: G06F 3/03545 Pens or stylus
• 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 is provided. A photo transmission/reception unit includes a phototransmitter which projects light along a plane of an input region, and a photoreceptor which detects incoming light. A reflector is arranged on a rim portion of the input region, and reflects incident light from the phototransmitter toward the photoreceptor. A detection unit detects a shade formed by the pointing operation of a pointing device using the photo transmission/reception unit. And an output unit calculates a coordinate value of the position based on a state of the detected shade, and outputs information of the coordinate value. The pointing device includes a transmission unit configured to transmit a control signal including information of a unique identifier based on the pointing operation, and the output unit extracts the information of the identifier from the control signal transmitted based on the pointing operation associated with the shade, and appends the information of the coordinate value when that information is output.

Claims

1. A coordinate input apparatus comprising:

a photo transmission/reception unit having a phototransmitter which projects light along a plane of an input region, and a photoreceptor which detects incoming light, said photoreceptor being controlled by control signals to have detection periods during which the incoming light is detected;

a reflector which is arranged on a rim portion of the input region, and configured to reflect incident light from the phototransmitter in said photo transmission/reception unit toward the photoreceptor in that photo transmission/reception unit;

a pointing device including a transmission unit configured to transmit an optical signal including information regarding a unique identifier based on a pointing operation, and used to make the pointing operation for pointing to an arbitrary position in the input region;

a detection unit configured to detect a shade formed by the pointing operation of said pointing device and the optical signal that is transmitted from the transmission unit based on the pointing operation, using said photo transmission/reception unit; and

an output unit configured

to detect the optical signal that is transmitted from the transmission unit based on the pointing operation, when the detection unit detects a plurality of shades in a single detection period,

to determine which one of the plurality of shades corresponds to the optical signal, in accordance with the positions of the plurality of shades and a position at which the optical signal is detected,

to calculate a coordinate value of the position on the basis of the determined one of the plurality of shades corresponding to the optical signal, and

to append the identifier included in the optical signal to the coordinate value calculated on the basis of the determined one of the plurality of shades.

2. The apparatus according to claim 1, wherein said output unit calculates a plurality of coordinate values of plurality of shades when said detection unit detects the plurality of shades.

3. The apparatus according to claim 2, wherein said output unit skips a calculation of the coordinate value for the shade for which no corresponding optical signal is detected.

6. The apparatus according to claim 1, further comprising a display device overlaid on the input region.

7. The apparatus according to claim 1, wherein said output unit turns off the phototransmitter and detects the optical signal, and when the phototransmitter is turned on said detection unit detects the shade.

4. A method of controlling a coordinate input apparatus which has a photo transmission/reception unit having a phototransmitter which projects light along a plane of an input region, and a photoreceptor which detects incoming light and is controlled by control signals to have detection periods during which the incoming light is detected, a reflector which is arranged on a rim portion of the input region, and configured to reflect incident light from the phototransmitter in the photo transmission/reception unit toward the photoreceptor in that photo transmission/reception unit, and a pointing device which includes a transmission unit configured to transmit an optical signal including information regarding a unique identifier based on a pointing operation and is used to make a pointing operation for to pointing an arbitrary position in the input region, the method comprising the steps of:

detecting a shade formed by the pointing operation of the pointing device using the photo transmission/reception unit;

detecting using the photoreceptor the optical signal transmitted from the transmission unit based on the pointing operation when a plurality of shades are detected in a single detection period;

determining which one of the plurality of shades corresponds to the optical signal, in accordance with position of the plurality of shades and a position at which the optical signal is detected;

calculating a coordinate value of the position on the basis of the determined one of the plurality of shades corresponding to the optical signal; and

appending the identifier included in the optical signal to the coordinate value calculated on the basis of the determined one of the plurality of shades.

8. The method according to claim 4, wherein said shade detecting step turns on the phototransmitter and detects the shade, and said optical signal detecting step turns off the phototransmitter and detects the optical signal when the plurality of shades are detected in said shade detecting step.

5. A coordinate input apparatus comprising:

a pointing device used for a pointing operation and including a transmission unit configured to transmit based on the pointing operation an optical signal including an identifier of the pointing device;

reception means for receiving incoming light, said reception means being controlled by control signals to have detection periods for detecting the incoming light;

first detection means for detecting based on said reception means of a shade formed by the pointing operation device;

second detection means for detecting based on said reception means the optical signal transmitted by the pointing of the pointing device when said first detection means detects a plurality of shades in a single detection period;

determining means for determining which one of a plurality of shades corresponds to the optical signal, in accordance with the positions of the plurality of shades and a position at which the optical signal is detected;

calculating means for calculating position information on the basis of the determined one of the plurality of shades corresponding to the optical signal; and

association means for associating the identifier of the pointing device included in the optical signal with the position information corresponding to the determined one of the plurality of shades corresponding to the optical signal.

9. The apparatus according to claim 5, wherein said first detection means detects turns on a phototransmitter for lighting an input area and detects the shade, and said second detection means turns off the phototransmitter and detects the optical signal when said first detection unit means detects the plurality of shades.