Optical position detection device, light receiving unit, and display system with input function

• US 8,854,337 B2
• Filed: 04/04/2012
• Issued: 10/07/2014
• Est. Priority Date: 04/06/2011
• Status: Active Grant

• Current Assignee: Columbia Peak Ventures, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Nakanishi, Daisuke
• Primary Examiner(s): Lao, Lun-Yi
• Assistant Examiner(s): DEADERICK, ELLIOTT J
• Application Number:
  US13/439,348
• Publication Number:
  US 20120256825A1
• Time in Patent Office: 916 Days
• Field of Search: 345156-158, 345/166, 345175-176, 345/179, 359/869, 178 1809- 1811, 178/19.05, 178/119, 250330-334, 25022713-22714
• US Class Current: 345/175
• CPC Class Codes: G01S 17/46 Indirect determination of position data
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G01S 7/4816 of receivers alone
• 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

Abstract

An optical position detection device includes a light receiving section receiving detection light reflected from a target object located in a detectable space through which detection light is radially emitted along an XY plane. The light receiving section includes a light receiving element and a concave mirror. A first cross section (XY cross section) of the reflective surface of the concave mirror is an arc, and a second cross section (YZ cross section) perpendicular to the first cross section is a quadratic curve. Therefore, in the in-plane direction of the XY plane, even light incident from an oblique direction with respect to the light receiving section is reflected by the concave mirror to the light receiving element. In the in-plane direction of the YZ plane, however, the range where the light reaches the light receiving element is limited via the concave mirror.

Claims

1. An optical position detection device that detects a position of a target object, comprising:

a light source section that emits detection light toward the target object, the detection light being distributed into a first light intensity distribution and a second light intensity distribution that is different from the first light intensity distribution;

a light receiving section that has a light receiving element, the light receiving element receiving reflected light of the detection light reflected from the target object; and

a position detecting section that detects the position of the target object based on a light receiving result of the light receiving section, wherein

the first light intensity distribution and the second light intensity distribution are alternatively formed,

the light receiving result includes at least two reflected light intensities corresponding to the first and second light intensity distributions, and

the light receiving section includes;

a concave mirror with a reflective surface, the reflecting surface having a first cross section and a second cross section perpendicular to the first cross section, the first cross section is an arc, and the second cross section is a quadratic curve; and

the light receiving element that is located at the center of the arc in a plan view of the first cross section and on an axis of symmetry of the quadratic curve in a plan view of the second cross section.

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

wherein the light receiving element is located at the center of the quadratic curve.

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

wherein the quadratic curve is an arc.

4. The optical position detection device according to claim 3,

wherein a radius of curvature of the arc of the second cross section is smaller than a radius of curvature of the arc of the first cross section.

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

wherein the quadratic curve is a parabola.

6. The optical position detection device according to claim 1, wherein

a size of the arc and a size of the quadratic curve are different from each other.

7. An optical position detection device that detects a position of a target object, comprising:

a light source section that emits detection light toward the target object, the detection light being distributed into a first light intensity distribution and a second light intensity distribution that is different from the first light intensity distribution;

a light receiving section that has a light receiving element, the light receiving element receiving reflected light of the detection light reflected from the target object; and

a position detecting section that detects the position of the target object based on a light receiving result of the light receiving section, wherein

the first light intensity distribution and the second light intensity distribution are alternatively formed,

the light receiving result includes at least two reflected light intensities corresponding to the first and second light intensity distributions, and

the light receiving section includes;

a concave mirror having a plurality of reflective surfaces, each reflective surface having a first cross section and a second cross section perpendicular to the first cross section, each first cross section is an arc, and each second cross section is a straight line, the plurality of reflective surfaces are arrayed along a normal line of the first cross sections; and

the light receiving element that is located at the center of the arcs of the plurality of reflective surfaces in a plan view of the first cross sections, and

an angle formed by a normal line of each of the reflective surfaces and the first cross section increases as a distance from the light receiving element increases along the normal line of the first cross sections.

8. The optical position detection device according to claim 7, wherein a size of the arc and a size of the straight line are different from each other.

9. A display system with an input function, comprising:

a light source section that emits detection light toward the target object, the detection light being distributed into a first light intensity distribution and a second light intensity distribution that is different from the first light intensity distribution;

a light receiving section that has a light receiving element, the light receiving element receiving reflected light of the detection light reflected from the target object;

a position detecting section that detects a position of the target object based on a light receiving result of the light receiving section; and

a display section switching an image displayed on a display surface based on a position detection result of the position detecting section, wherein

the first light intensity distribution and the second light intensity distribution are alternatively formed,

the light receiving result includes at least two reflected light intensities corresponding to the first and second light intensity distributions, and

the light receiving section includes;

a concave mirror with a reflective surface, the reflecting surface having a first cross section and a second cross section perpendicular to the first cross section, the first cross section is an arc, and the second cross section is a quadratic curve; and

the light receiving element that is located at the center of the arc in a plan view of the first cross section and on an axis of symmetry of the quadratic curve in a plan view of the second cross section.

10. The display system with an input function according to claim 9,

wherein the light receiving element is located at the center of the quadratic curve.

11. A display system with an input function, comprising:

a light source section that emits detection light toward the target object, the detection light being distributed into a first light intensity distribution and a second light intensity distribution that is different from the first light intensity distribution;

a light receiving section that has a light receiving element, the light receiving element receiving reflected light of the detection light reflected from the target object;

a position detecting section that detects a position of the target object based on a light receiving result of the light receiving section; and

a projection type display section switching a projected image based on a position detection result of the position detecting section, wherein

the first light intensity distribution and the second light intensity distribution are alternatively formed,

the light receiving result includes at least two reflected light intensities corresponding to the first and second light intensity distributions, and

the light receiving section includes;

a concave mirror with a reflective surface, the reflecting surface having a first cross section and a second cross section perpendicular to the first cross section, the first cross section being an arc, and the second cross section being a quadratic curve; and

the light receiving element that is located at the center of the arc in a plan view of the first cross section and on an axis of symmetry of the quadratic curve in a plan view of the second cross section.

12. The display system with an input function according to claim 11,

wherein the light receiving element is located at the center of the quadratic curve.