Diffractive light distribution for photosensor array-based lidar receiving system

Patent metadata

Field	Value
Publication number	US-12461208-B2
Application number	US-202117544920-A
Country	US
Kind code	B2
Filing date	Dec 7, 2021
Priority date	Dec 7, 2021
Publication date	Nov 4, 2025
Grant date	Nov 4, 2025

Abstract

Embodiments of the disclosure provide an optical sensing system containing a diffractive optical element, and an optical sensing method using the same. For example, the optical sensing system includes a laser emitter configured to emit an optical signal. The optical sensing system further includes a steering device configured to direct the emitted optical signal toward an environment surrounding the optical sensing system. The optical sensing system additionally includes a diffractive optical element configured to diffract the optical signal returning from the environment to form a plurality of beams focusing at a plurality of spots on a focal plane. The optical sensing system additionally includes a photosensor array placed at the focal plane, configured to detect the plurality of beams diffracted by the diffractive optical element at the plurality of spots, wherein the photosensor array comprises a plurality of sensitive elements.

First claim

What is claimed is:

1 . An optical sensing system, comprising:
a laser emitter, configured to emit an optical signal; a steering device, configured to direct the emitted optical signal toward an environment surrounding the optical sensing system; a diffractive optical element, configured to diffract the optical signal returning from the environment to form a plurality of beams focusing at a plurality of spots on a focal plane, wherein the optical signal returning from the environment has a light intensity profile of one of a Gaussian distribution or a normal distribution and each of the plurality of beams has a top-hat intensity profile comprising sharp edges and a step energy drop-off between the plurality of spots; and a photosensor array placed at the focal plane, configured to detect the plurality of beams diffracted by the diffractive optical element at the plurality of spots, wherein the photosensor array comprises a plurality of sensitive elements.

2 . The optical sensing system of claim 1 , wherein the diffractive optical element comprises a periodic grating structure profile to diffract and propagate the plurality of beams toward the plurality of spots on the focal plane.

3 . The optical sensing system of claim 2 , wherein the periodic grating structure profile of the diffractive optical element comprises a thin structure of rings on a surface with each different ring having a tooth-like profile.

4 . The optical sensing system of claim 1 , wherein sensitive areas of two sensitive elements of the photosensor array corresponding to two consecutive spots on the focal plane are separated by a non-sensitive area in between.

5 . The optical sensing system of claim 1 , further comprising a receiving lens configured to focus the plurality of beams onto the plurality of sensitive elements of the photosensor array corresponding to the plurality of spots on the focal plane.

6 . The optical sensing system of claim 2 , wherein the plurality of beams diffracted by the diffractive optical element have predefined intervals, intensity ratios, and a symmetrical distribution.

7 . The optical sensing system of claim 6 , wherein the predefined intervals, intensity ratios, and symmetrical distribution of the plurality of beams are determined by the periodic grating structure profile of the diffractive optical element.

8 . The optical sensing system of claim 1 , wherein each split laser beam is detected by at least two consecutive sensitive elements of the photodetector array.

9 . The optical sensing system of claim 1 , wherein the laser emitter comprises a multi-channel laser bar that includes a plurality of laser emitters configured to emit a plurality of optical signals simultaneously.

10 . The optical sensing system of claim 9 , wherein the diffractive optical element is configured to diffract the plurality of optical signals returning from the environment simultaneously.

11 . An optical sensing method, comprising:
emitting, by a laser emitter of an optical sensing system, an optical signal toward an environment surrounding the optical sensing system; directing, by a steering device of the optical sensing system, the emitted optical signal toward the environment surrounding the optical sensing system; diffracting, by a diffractive optical element of the optical sensing system, the optical signal returning from the environment to form a plurality of beams focusing at a plurality of spots on a focal plane, wherein the optical signal returning from the environment has a light intensity profile of one of a Gaussian distribution or a normal distribution and each of the plurality of beams has a top-hat intensity profile comprising sharp edges and a step energy drop-off between the plurality of spots; and detecting, by a photosensor array of the optical sensing system, the plurality of beams diffracted by the diffractive optical element at the plurality of spots, wherein the photosensor array comprises a plurality of sensitive elements.

12 . The optical sensing method of claim 11 , wherein the diffractive optical element comprises a periodic grating structure profile to diffract and propagate the plurality of beams toward the plurality of spots on the focal plane.

13 . The optical sensing method of claim 12 , wherein the periodic grating structure profile of the diffractive optical element comprises a thin structure of rings on a surface with each different ring having a tooth-like profile.

14 . The optical sensing method of claim 11 , wherein sensitive areas of two sensitive elements of the photosensor array corresponding to two consecutive spots on the focal plane are separated by a non-sensitive area in between.

15 . The optical sensing method of claim 11 , further comprising:
focusing, by a receiving lens of the optical sensing system, the plurality of beams onto the plurality of sensitive elements of the photosensor array corresponding to the plurality of spots on the focal plane.

16 . A receiver of an optical sensing system, comprising:
a diffractive optical element, configured to diffract an optical signal returning from an environment surrounding the optical sensing system, to form a plurality of beams focusing at a plurality of spots on a focal plane, wherein the optical signal is emitted and directed toward the environment by a transmitter of the optical sensing system, the optical signal returning from the environment has a light intensity profile of one of a Gaussian distribution or a normal distribution, and each of the plurality of beams has a top-hat intensity profile comprising sharp edges and a step energy drop-off between the plurality of spots; a receiving lens, configured to focus the plurality of beams at the plurality of spots on the focal plane; and a photosensor array, configured to detect the plurality of beams diffracted by the diffractive optical element at the plurality of spots, wherein the photosensor array comprises a plurality of sensitive elements.

Assignees

• Beijing Voyager Tech Co Ltd

Inventors

• Wang Youmin
• Lu Yue

Classifications

• G01S7/4816 Primary

  of receivers alone · CPC title

• G01S17/89

  for mapping or imaging · CPC title

• G01B11/22

  for measuring depth · CPC title

• G01S7/4814

  of transmitters alone · CPC title

• G01S7/4817 Primary

  relating to scanning · CPC title