OBJECT DETECTION APPARATUS

• US 20140034817A1
• Filed: 07/31/2013
• Published: 02/06/2014
• Est. Priority Date: 08/06/2012
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Tadashi Nakamura
• Inventors: NAKAMURA, Tadashi, Imai, Shigeaki, Suzuki, Shuichi, Nakajima, Mitsuru, Yoshimura, Kenichi, Funato, Hiroyoshi
• Granted Patent: US 9,304,228 B2
• Time in Patent Office: Days
• US Class Current: 250/221
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01V 8/22 using reflectors
• CPC Class Codes: G02B 26/123 Multibeam scanners, e.g. using multiple light sources or beam splitters

Abstract

An object detection apparatus includes an incident optical system, which includes light source units and a combining unit combining light beams emitted from the light source units; a deflection unit including rotating reflection parts that deflect the light beams to scan and be irradiated on a predetermined range of an object; an imaging unit forming an image based on the light from the predetermined range of the object; and an optical detection unit detecting the object based on the light received via the imaging unit. Further the combining unit combines the light beams such that each of the combined light beams passes a single light path when projected onto a predetermined plane, and each of the light paths exists outside a region of the deflection unit when projected onto the first plane.

Claims

1. An object detection apparatus comprising:

an incident optical system including

a plurality of light source units, and

a combining unit configured to combine light beams emitted from the light source units;

a deflection unit including rotating reflection parts that deflect the light beams to scan and be irradiated on a predetermined range of an object;

an imaging unit configured to form an image based on reflected light or scattered light from the predetermined range of the object; and

an optical detection unit configured to detect the object based on the reflected light or the scattered light received via the imaging unit,

wherein the combining unit is configured to combine the light beams emitted from the light source units such that each of the combined light beams tra travels a single light path when the combined light beams are projected onto a first plane, and

wherein each of the light paths exists outside a region of the deflection unit when the light paths are projected onto the first plane.

2. The object detection apparatus according to claim 1,

wherein the light source units include respective light sources and optical devices that change a state of the light beams emitted from the light sources into a predetermined state,

wherein when the light sources and the optical devices are projected onto a second plane, which is perpendicular to the first plane, the light sources and the optical devices of the light source units are arranged in different positions, respectively, so that the light beams emitted from the light sources of the light source units are incident on the deflection unit at different angles when the light beams are projected onto the second plane, and

wherein the first plane is perpendicular to a plane that includes the light beams to be incident on the deflection unit.

3. The object detection apparatus according to claim 2,

wherein the light source units are arranged such that the light beams emitted from the light sources cross each other in a region in the second plane and rays, which are emitted from the light sources to become respective geometric centers of the light beams emitted from the light sources, do not cross each other in any region in the second plane.

4. The object detection apparatus according to claim 1,

wherein when it is assumed that a three-dimensional coordinate system is defined by X, Y, and Z axes in which the X axis extends from the deflection unit to a center of the predetermined range of the object, the Y axis extends in the direction parallel to the scanning direction of the deflection unit, and the Z axis extends in the direction parallel to the rotating axis of the deflection unit, the first plane corresponds to the XY plane.

5. The object detection apparatus according to claim 2, further comprising:

a light source driving unit configured to drive and control the light source units,

wherein the optical detection unit includes an optical detector, which has a light receiving surface to receive the light beams transmitted via the imaging unit, and an optical detector driving unit that drives and controls the optical detector,

wherein the light source units and the optical detection unit are arranged so that an emission direction the light beams emitted from the light sources is perpendicular to the light receiving surface of the optical detector, and

wherein the light source driving unit and the optical detector driving unit are integrally provided.

6. The object detection apparatus according to claim 1, further comprising:

a light source driving unit configured to drive and control the light source units,

wherein the deflection unit includes a deflector having a rotation axis and a deflector driving unit drives and controls the deflector,

wherein the light source driving unit and the deflector driving unit are arranged so that the emission direction of the light beams emitted from the light sources is parallel to the rotation axis, and

wherein the light source driving unit and the deflector driving unit are integrally provided.

7. The object detection apparatus according to claim 1,

wherein the combining unit is a polarization beam splitter.

8. The object detection apparatus according to claim 7,

wherein the light source units include respective light sources having an active layer,

wherein the active layers are arranged in the same direction,

wherein the object detection apparatus further comprises a polarization direction changing unit arranged between one of the light sources and the combining unit, and configured to change the polarization direction of the light beams.

9. The object detection apparatus according to claim 7, further comprising:

a polarization direction changing unit configured to change a state of the light beams combined by the combining unit.