Object detecting apparatus, object detecting method, and design method of object detecting apparatus

1. An object detecting apparatus comprising:

a laser light source comprising a plurality of light-emitting points arranged thereon;

a lens assembly configured to convert laser light emitted by the plurality of light-emitting points to a laser beam with a divergence angle in an arrangement direction of the plurality of light-emitting points;

a light-receiving element that is a silicon photomultiplier (SiPM);

an optical assembly configured to project the laser beam outward along an optical axis and guide an incident light toward the light-receiving element along the optical axis;

a scanning assembly configured to periodically change projection direction of the laser beam; and

an object detecting assembly configured to detect a distance to an object located along an optical path of the projected laser beam and a direction in which the object is located, based on a projection timing and the projection direction of the laser beam and a timing of a light detection signal output from the light-receiving element,

the optical assembly comprising:

an optical element configured to separate the incident light from an optical path of the laser beam to be projected;

a collective lens configured to form an image of the incident light separated by the optical element on a focal plane; and

an aperture located on the focal plane of the collective lens,

wherein α≤β is satisfied, in which a is the divergence angle, and D is a size of a light passing region of the aperture corresponding to the divergence angle along the arrangement direction, and d is a distance between the collective lens and the aperture, and β=arctan(D/d).

2. The object detecting apparatus according to claim 1 ,

wherein 1≤β/α≤3 is satisfied.

3. The object detecting apparatus according to claim 1 ,

wherein the incident light passed through the collective lens is incident on an entire light-receiving surface of the silicon photomultiplier.

4. The object detecting apparatus according to claim 1 ,

further comprising a light diffuser between the aperture and the light-receiving element.

5. An object detecting method comprising:

converting laser light emitted by a plurality of light-emitting points to a laser beam having a divergence angle in an arrangement direction of the plurality of light-emitting points, by a lens assembly;

projecting the laser beam outward along an optical axis and periodically changing projection direction of the laser beam, and guiding an incident light toward a light-receiving element along the optical axis;

separating the incident light by an optical element from an optical path of the laser beam to be projected, and forming an image of the separated incident light on a focal plane by a collective lens;

limiting the incident light passing through the focal plane by an aperture located on the focal plane, wherein α≤β is satisfied, in which α is the divergence angle, and D is a size of a light passing region of the aperture corresponding to the divergence angle along the arrangement direction, and d is a distance between the collective lens and the aperture, and β=arctan(D/d);

making the incident light passing through the light passing region of the aperture fall on a silicon photomultiplier (SiPM); and

detecting a distance to an object located along an optical path of the projected laser beam and a direction in which the object is located, based on a projection timing and the projection direction of the laser beam and a timing of a light detection signal output from the SiPM.

6. A design method of an object detecting apparatus,

the object detecting apparatus comprising:

a laser light source comprising a plurality of light-emitting points arranged thereon;

a lens assembly configured to convert laser light emitted by the plurality of light-emitting points to a laser beam with a divergence angle in an arrangement direction of the plurality of light-emitting points;

a light-receiving element that is a silicon photomultiplier (SiPM);

an optical assembly configured to project the laser beam outward along an optical axis and guide an incident light toward the light-receiving element along the optical axis;

a scanning assembly configured to periodically change projection direction of the laser beam; and

an object detecting assembly configured to detect a distance to an object located along an optical path of the projected laser beam and a direction in which the object is located, based on a projection timing and the projection direction of the laser beam and a timing of a light detection signal output from the light-receiving element,

the optical assembly comprising:

an optical element configured to separate the incident light from an optical path of the laser beam to be projected;

a collective lens configured to form an image of the incident light separated by the optical element on a focal plane; and

an aperture located on the focal plane of the collective lens, and

the design method comprising:

determining a size D of a light passing region of the aperture in a direction corresponding to the divergence angle along the arrangement direction based on the divergence angle α and a distance d between the collective lens and the aperture, such that α≤β is satisfied, where β=arctan(D/d).

7. The design method of the object detecting apparatus according to claim 6 ,

wherein the size D is determined such that 1≤β/α≤3 is satisfied.