Object detector and sensor

• US 10,302,767 B2
• Filed: 10/10/2017
• Issued: 05/28/2019
• Est. Priority Date: 12/06/2013
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Akatsu, Kazuhiro, Nakamura, Tadashi, Sakai, Kohji
• Primary Examiner(s): Sohn, Seung C
• Application Number:
  US15/729,324
• Publication Number:
  US 20180038959A1
• Time in Patent Office: 595 Days
• Field of Search: 250221
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 7/4815 using multiple transmitters
• CPC Class Codes: G01S 7/484 Transmitters
• CPC Class Codes: G01S 7/4868 Controlling received signal intensity or exposure of sensor
• CPC Class Codes: G01S 7/51 Display arrangements
• CPC Class Codes: H05B 47/115 by determining the presence or movement of objects or living beings
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

An object detector includes a projector including a light source having a two-dimensionally arranged plurality of light emitter groups, each of the light emitter groups having a plurality of light emitters, a light receiver which receives light emitted from the projector, and reflected by an object, and a light source driver which lights on and lights off each of the light emitter groups of the light source.

Claims

1. An object detector, comprising:

a projector including a light source having a two-dimensionally arranged plurality of light emitter groups, each of the light emitter groups having a plurality of light emitters and configured to emit an adjustable emission light volume;

a light receiver which receives light emitted from the projector and reflected by an object;

a light source driver which illuminates and turns off each of the light emitter groups of the light source; and

a processor which sequentially illuminates and turns off the plurality of light emitter groups using the light source driver, and obtains distance information to the object based on lighting-on timing of one of the light emitter groups which has emitted light and light-receiving timing of the light receiver when the light receiver receives light reflected by the object, the processor being configured to adjust the emission light volume based on the distance information to the object.

2. The object detector according to claim 1, wherein the processor sequentially causes the light source driver to illuminate one of the light emitter groups which is at least one light emitter group away from a previously illuminated light emitter group.

3. The object detector according to claim 1, wherein:

the projector includes a projection optical system disposed on an optical path of light emitted from the light source, and

a focal length of the projection optical system is variable.

4. The object detector according to claim 1, wherein:

the light receiver includes a single light-receiving element having a light receiving area, and

a size of the light-receiving area of the light receiver is a same size as a size of an emission area of the plurality of light emitter groups when the plurality of light emitter groups in the light source are simultaneously illuminated.

5. The object detector according to claim 1, wherein:

the plurality of light emitter groups is disposed along a first direction and a second direction orthogonal to each other,

the light receiver includes a light-receiving optical system which collects the light reflected by the object, and

the light-receiving optical system has a focal length which differs between the first direction and the second direction.

6. The object detector according to claim 1, wherein the light emitter groups disposed in a peripheral part of the plurality of light emitter groups have an emission light volume larger than that of the light emitter groups disposed in a central part of the plurality of light emitter groups.

7. An object detector, comprising:

a projector including a light source having a two-dimensionally arranged plurality of light emitter groups, each of the light emitter groups having a plurality of light emitters;

a light receiver which receives light emitted from the projector, and reflected by an object;

a light source driver which illuminates and turns off each of the light emitter groups of the light source; and

a processor which sequentially illuminates and turns off the plurality of light emitter groups using the light source driver, and obtains distance information to the object based on lighting-on timing of the light emitter group and light-receiving timing of the light receiver when the light receiver receives light reflected by the object, the processor being configured to adjust a number of light emitters to be illuminated in one of the light emitter groups based on the distance information to the object.

8. The object detector according to claim 7, wherein the processor sequentially illuminates the light emitter group at least one light emitter group away from a previously illuminated light emitter group.

9. The object detector according to claim 7, wherein:

the projector includes a projection optical system disposed on an optical path of light emitted from the light source, and

a focal length of the projection optical system is variable.

10. The object detector according to claim 7, wherein:

the light receiver includes a single light-receiving element having a light receiving area, and

a size of the light-receiving area is a same size as a size of an emission area of the plurality of light emitter groups when the plurality of light emitter groups in the light source are simultaneously illuminated.

11. The object detector according to claim 7, wherein:

the plurality of light emitter groups is disposed along a first direction and a second direction orthogonal to each other,

the light receiver includes a light-receiving optical system which collects the light reflected by the object, and

the light-receiving optical system has a focal length which differs between the first direction and the second direction.

12. The object detector according to claim 7, wherein the light emitter groups disposed in a peripheral part of the plurality of light emitter groups have an emission light volume larger than that of the light emitter groups disposed in a central part of the plurality of light emitter groups.

13. The object detector according to claim 7, wherein the processor sequentially causes the light source driver to illuminate one of the light emitter groups which is at least one light emitter group away from a previously illuminated light emitter group.

14. The object detector according to claim 7, wherein:

the projector includes a projection optical system disposed on an optical path of light emitted from the light source, and

a focal length of the projection optical system is variable.

15. The object detector according to claim 7, wherein:

the light receiver includes a single light-receiving element having a light receiving area, and

a size of the light-receiving area of the light receiver is a same size as a size of an emission area of the plurality of light emitter groups when the plurality of light emitter groups in the light source are simultaneously illuminated.

16. The object detector according to claim 7, wherein:

the plurality of light emitter groups is disposed along a first direction and a second direction orthogonal to each other,

the light receiver includes a light-receiving optical system which collects the light reflected by the object, and

the light-receiving optical system has a focal length which differs between the first direction and the second direction.

17. The object detector according to claim 7, wherein the light emitter groups disposed in a peripheral part of the plurality of light emitter groups have an emission light volume larger than that of the light emitter groups.

18. An object detector, comprising:

a projector including a light source having a two-dimensionally arranged plurality of light emitter groups, each of the light emitter groups having a plurality of light emitters;

a light receiver which receives light emitted from the projector, and reflected by an object;

a light source driver which illuminates and turns off each of the light emitter groups of the light source; and

a processor which sequentially illuminates and turns off the plurality of light emitter groups with the light source driver, and obtains distance information to the object based on lighting-on timing of one of the light emitter groups which has emitted light and light-receiving timing of the light receiver when the light receiver receives light reflected by the object, the processor being configured to adjust the emission light volume based on the distance information to the object.