Monostatic LiDAR transceiver system

Patent metadata

Field	Value
Publication number	US-11947040-B2
Application number	US-202218056989-A
Country	US
Kind code	B2
Filing date	Nov 18, 2022
Priority date	May 1, 2020
Publication date	Apr 2, 2024
Grant date	Apr 2, 2024

Abstract

A LiDAR system includes a light source and an arrayed micro-optic configured to receive light from the light source so as to produce and project a two-dimensional array of light spots on a scene. The LiDAR system also includes receiver optics having an array of optical detection sites configured so as to be suitable for establishing a one-to-one correspondence between light spots in the two-dimensional array and optical detection sites in the receiver optics. The LiDAR system further includes a birefringent prism and a lens. The LiDAR system may also include a mask placed in the light path between the birefringent prism and the receiver optics. Alternatively, the LiDAR system may include a controller programmed to activate or deactivate each optical detection site.

First claim

What is claimed is:

1. A method for operation of a light detection and ranging (LiDAR) system, comprising:
producing and projecting a two-dimensional array of light spots on a scene, by an arrayed micro-optic having an array of optical emission sites, using light emitted from a light source, such that the light travels a light path from the arrayed micro-optic to a lens, from the lens to a birefringent prism, from the birefringent prism to a quarter wave plate, and from the quarter wave plate to the scene, wherein the light as reflected from the scene travels from the scene to the quarter wave plate, from the quarter wave plate to the birefringent prism, from the birefringent prism to the lens, and from the lens to receiver optics having an array of optical detection sites; and
receiving, by the receiver optics, the light as reflected from the scene, each of the light spots in the two-dimensional array having a one-to-one correspondence with an optical detection site in the receiver optics, a mask having an array of apertures being located in the light path between the lens and the receiver optics, each of the apertures being located in front of a respective one of the optical detection sites.

2. The method of claim 1 , wherein the birefringent prism comprises a birefringent wedge.

3. The method of claim 1 , wherein the arrayed micro-optic comprises a micro-opto-electro-mechanical system (MOEMS) chip having a waveguide.

4. The method of claim 3 , wherein the mask is coupled to the MOEMS chip.

5. The method of claim 3 , wherein a distance between the MOEMS chip and the receiver optics is in the range of 5 to 30 micrometers.

6. The method of claim 3 , wherein the waveguide comprises a transparent substrate.

7. The method of claim 3 , wherein the MOEMS chip and the receiver optics form a monolithic structure.

8. The method of claim 7 , wherein the receiver optics include a detector chip and wherein the MOEMS chip is bonded to the detector chip.

9. The method of claim 3 , wherein the MOEMS chip comprises a plurality of optical gratings.

10. The method of claim 9 , wherein the plurality of optical gratings and the receiver optics are arranged in the same plane.

11. The method of claim 9 , wherein each of the plurality of optical gratings corresponds to one optical emission site of the array of optical emission sites.

12. The method of claim 9 , wherein a plurality of grating couplers couple incident light from each grating of the plurality of optical gratings into the waveguide.

13. The method of claim 12 , wherein the plurality of grating couplers are made from silicon nitride, wherein the optical gratings are made from silicon or silicon nitride, and wherein the waveguide is made from silicon or silicon nitride.

14. The method of claim 1 , wherein the mask comprises a layer having a plurality of openings, each opening being in the light path leading to a respective one of the optical detection sites.

15. The method of claim 14 , wherein the layer is made from a material selected from the group consisting of aluminum, copper, gold, platinum, chromium, titanium, silicon, carbon, graphite, or combinations thereof.

16. The method of claim 1 , wherein a shape of at least one of the apertures corresponds to a calculated or measured aberrated shape of a light spot received in a focal plane of the respective optical detection site.

17. The method of claim 1 , wherein a shape of at least one of the apertures is different from a shape of another one of the apertures.

18. The method of claim 1 , wherein a shape of at least one of the apertures is selected to mitigate variations in manufacturing of the respective optical detection site or a thermal shift of the respective optical detection site.

19. The method of claim 1 , further comprising, by a controller, selectively activating or deactivating each optical detection site of the array of optical detection sites.

20. The method of claim 19 , wherein a size of each optical detection site is smaller than a size of each light spot projected onto the receiver optics.

21. The method of claim 19 , further comprising, by the controller, selectively activating or deactivating each optical detection site to correspond to a calculated or measured aberrated shape of a light spot received in a focal plane of the array of optical detection sites.

22. The method of claim 19 , further comprising, by the controller, selectively activating or deactivating each optical emission site of the array of optical emission sites.

23. The method of claim 22 , wherein an activation state of at least one emission site of the array of optical emission sites determines an activation state of an associated at least one optical detection site of the array of optical detection sites.

24. The method of claim 1 , wherein the optical detection sites are single-photon avalanche diode (SPAD) detectors.

25. The method of claim 1 , wherein the optical detection sites are silicon photomultiplier (SiPM) detectors.

26. The method of claim 1 , wherein the birefringent prism shifts a beam of light traveling through the birefringent prism by half a degree or less.

Assignees

• Charles Stark Draper Laboratory Inc

Inventors

• Moebius Michael G
• Benney Lucas D
• Spector Steven J
• Byrnes Steven J

Classifications

• G01S7/4816 Primary

  of receivers alone · CPC title

• G01S7/4813

  Housing arrangements · CPC title

• G01S7/499 Primary

  using polarisation effects · CPC title

• G01S17/02

  Systems using the reflection of electromagnetic waves other than radio waves (G01S17/66 takes precedence) · CPC title

• G01S7/4815

  using multiple transmitters · CPC title