Optical position detecting device and display device with position detecting function

• US 8,581,892 B2
• Filed: 05/13/2011
• Issued: 11/12/2013
• Est. Priority Date: 06/11/2010
• Status: Expired due to Fees

• Current Assignee: Columbia Peak Ventures, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Yoshida, Kazuki
• Primary Examiner(s): Tzeng, Fred
• Application Number:
  US13/107,168
• Publication Number:
  US 20110304600A1
• Time in Patent Office: 914 Days
• Field of Search: 345/207, 345/175
• US Class Current: 345/207
• 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

An optical position detecting device includes: a plurality of detection light source sections which emits a detection light; a light source driving section which turns on a part of the plurality of detection light source sections in a first period, and turns on the other part thereof in a second period; a first light detecting section which detects the detection light reflected by a object; a second light detecting section which has a sensitivity peak in a wavelength band which is different from that of the first light detecting section and detects the detection light reflected by the object; and a position detecting section which detects the position of the object on the basis of the intensity of the detection light in the first light detecting section and the intensity of the detection light in the second light detecting section in the first and second periods.

Claims

1. An optical position detecting device comprising:

a plurality of detection light source sections which emits a detection light;

a light source driving section that turns on a part of the plurality of detection light source sections in a first period and that turns on the other part thereof in a second period;

a first light detector that has a first sensitivity peak in a first wavelength band and that detects the detection light reflected by an object so as to provide first detection light intensity;

a second light detector that has a second sensitivity peak in a second wavelength band that is different from the first wavelength band and that detects the detection light reflected by the object so as to provide second detection light intensity; and

a position detecting section that detects a position of the object based on the first detection light intensity and the second detection light intensity in the first and second periods.

2. The optical position detecting device according to claim 1,

wherein the position detecting section detects the position of the object based on a difference between the first light intensity and the second light intensity.

3. The optical position detecting device according to claim 1,

further comprising a light guiding plate which is provided with a light incident section to which the detection light emitted from the plurality of detection light source sections is incident and a light exiting section from which the detection light incident from the light incident section exits,

wherein a first light intensity distribution for a first coordinate detection in which a light intensity monotonically decreases from one side of a first direction which intersects with a light exiting direction of the detection light from the light guiding plate toward the other side thereof, and a second light intensity distribution for a first coordinate detection in which a light intensity monotonically decreases from the other side of the first direction to the one side thereof, are sequentially formed in the first period and the second period for the first coordinate detection.

4. The optical position detecting section according to claim 3, wherein a first light intensity distribution for a second coordinate detection in which a light intensity monotonically decreases from one side of a second direction which intersects with the light exiting direction of the detection light from the light guiding plate and the first direction toward the other side thereof, and a second light intensity distribution for a second coordinate detection in which a light intensity monotonically decreases from the other side of the second direction to the one side thereof, are sequentially formed in the first period and the second period for the second coordinate detection.

5. The optical position detecting device according to claim 1,

wherein the light source driving section drives the part of the plurality of detection light source sections and the other part thereof so that third and fourth detection light intensity in the first and second light detectors, respectively, when the part of the plurality of detection light source sections is turned on becomes equal to fifth and sixth detection light intensity in the first and second light detectors, respectively, when the other part thereof is turned on.

6. The optical position detecting device according to claim 1,

further comprising a reference light source section which emits a reference light incident to the first and second light detectors without being reflected by the object,

wherein the light source driving section drives the reference light source section and the part of the plurality of detection light source sections so that third and fourth detection light intensity in the first and second light detectors, respectively, when the reference light source section is turned on becomes equal to fifth and sixth detection light intensity in the first and second light detectors, respectively, when the part of the plurality of detection light source sections is turned on.

7. The optical position detecting device according to claim 1, wherein the detection light is infrared light.

8. A display device with a position detecting function which is provided with the optical position detecting device in claim 1, comprising:

an image generating device which forms an image,

wherein a detection light is emitted to be overlapped with the image.