Object detecting apparatus

1. An object detecting apparatus comprising:

a light projector that includes

an array light source in which each of a plurality of light emission areas emits light, and

a coupling lens;

a light-projection optical scanner that performs scanning with the light, which is emitted from the light projector, in a first direction;

a light-reception optical scanner that reflects reflected light, which is the light with which the scanning is performed, being reflected by an object to guide the reflected light;

a light receiver that includes a photodetector and an image forming lens and receives the reflected light reflected by the light-reception optical scanner and guided by the light-reception optical scanner to the light receiver; and

a processor to detect a presence/absence of the object based on emission timing at which the light is emitted from the light projector and light receiving timing at which the light receiver receives the reflected light,

wherein:

the plurality of light emission areas are disposed one-dimensionally in a direction parallel to a rotation axis of the light-projection optical scanner,

the light-projection optical scanner and the light-reception optical scanner rotate synchronously, and

a distance between the coupling lens and the light source is identical to a focal length of the coupling lens, and the photodetector is at a position farther than a focal length of the imaging forming lens when seen from the imaging forming lens; or alternatively, a distance between the coupling lens and the light source is longer than the focal length of the coupling lens, and the photodetector is at a position which is away from the imaging forming lens by a distance corresponding to the focal length of the imaging forming lens when seen from the imaging forming lens.

2. The object detecting apparatus according to claim 1 , wherein:

the processor determines a light emission area to be lighted among the plurality of light emission areas according to a detection region by the light used for the scanning.

3. The object detecting apparatus according to claim 1 , wherein:

the light-projection optical scanner is a polygon mirror including a plurality of reflection surfaces, and

light emitted from the different light emission areas are respectively projected on the reflection surfaces.

4. The object detecting apparatus according to claim 1 , wherein:

the light-projection optical scanner includes a polygon mirror including a plurality of reflection surfaces, and

light emitted from the different light emission areas is projected on one of the reflection surfaces while the one reflection surface performs scanning.

5. The object detecting apparatus according to claim 4 , wherein:

a range scanned by the one reflection surface is divided into a plurality of regions, and

the light emission areas to project the light are switched in one of the plurality of regions.

6. The object detecting apparatus according to claim 1 , wherein when detecting the object, the processor calculates a distance to the object based on the emission timing at which the light is emitted from the light projector and the light receiving timing at which the light receiver receives the reflected light.

7. The object detecting apparatus according to claim 6 , wherein the processor acquires a shape of the object based on a distance to the object in each emitting direction of the light emitted from the light-projection optical scanner.

8. A method to detect an object, comprising:

projecting light through a coupling lens from an array light source in which each of a plurality of light emission areas emits light;

light-projection optically scanning with the light emitted from the light source in a first direction;

light-reception optical scanning that reflects reflected light, which is the light with which the scanning is performed, being reflected by an object to guide the reflected light through an image forming lens to a light receiver including a photodetector;

receiving reflected light reflected by the light-reception optical scanning; and

detecting a presence/absence of the object based on emission timing at which the light is emitted and light receiving timing at which the reflected light is received,

wherein:

the plurality of light emission areas are arranged one-dimensionally in a direction parallel to a rotation axis of the light-projection optical scanning,

the light-projection optical scanning and the light-reception optical scanning rotate synchronously, and

a distance between the coupling lens and the light source is identical to a focal length of the coupling lens, and the photodetector is at a position farther than a focal length of the imaging forming lens when seen from the imaging forming lens; or alternatively, a distance between the coupling lens and the light source is longer than the focal length of the coupling lens, and the photodetector is at a position which is away from the imaging forming lens by a distance corresponding to the focal length of the imaging forming lens when seen from the imaging forming lens.

9. The method according to claim 8 , further comprising:

determining a light emission area to be lighted among the plurality of light emission areas according to a detection region by the light used for the light-projection optically scanning.

10. The method according to claim 8 , wherein the detecting comprises:

calculating a distance to the object based on emission timing at which the light is emitted and light receiving timing at which the reflected light is received.

11. The object detecting apparatus according to claim 1 , wherein each of the light emission areas is an aggregation of a plurality of light emission units.

12. The object detecting apparatus according to claim 1 , wherein:

the light-projection optical scanner and the light-reception optical scanner are integral.