Receive path for LiDAR system

Patent metadata

Field	Value
Publication number	US-12298399-B2
Application number	US-201916283563-A
Country	US
Kind code	B2
Filing date	Feb 22, 2019
Priority date	Feb 22, 2018
Publication date	May 13, 2025
Grant date	May 13, 2025

Abstract

In accordance with some embodiments, a light detection and ranging (LiDAR) system comprises: a light source configured to generate a pulse signal from the LiDAR system; one or more mirrors configured to steer a returned light pulse associated with the transmitted pulse signal along an optical receive path; a field lens positioned along the optical receive path, wherein the field lens is configured to redirect the returned light pulse; a fiber having a receiving end configured to receive the returned light pulse from the field lens along the optical receive path; and a light detector configured to receive the returned light pulse from an end of the fiber opposite the receiving end.

First claim

The invention claimed is:

1. A light detection and ranging (LiDAR) system comprising:
a light source configured to generate a pulse signal from the LiDAR system;
one or more mirrors configured to steer a returned light pulse associated with the transmitted pulse signal along an optical receive path wherein the one or more mirrors include a polygon scanner configured to rotate about an axis;
a field lens positioned along the optical receive path, wherein the field lens is configured to redirect the returned light pulse to within a predetermined area;
a fiber having a fiber core and a receiving end having a cross-sectional area that is equal to or greater than the predetermined area, and configured to receive the redirected returned light pulse from the field lens into the fiber core along the optical receive path wherein the fiber is configured to receive the redirected returned light pulse along a unidirectional receive path; and
a light detector configured to receive the returned light pulse from an end of the fiber core opposite the receiving end, wherein the light detector receives the returned light pulse through a coupling optic wherein a detecting area of the light detector is approximately equal to or smaller than the cross-sectional area of the fiber core.

2. The LiDAR system of claim 1 , wherein the field lens is configured to reduce walk-off error associated with the one or more mirrors.

3. The LiDAR system of claim 1 , wherein the polygon scanner is also configured to direct the transmitted pulse signal from the LiDAR system.

4. The LiDAR system of claim 1 , wherein the one or more mirrors include a parabolic mirror.

5. The LiDAR system of claim 1 wherein a variation in a speed of rotation of the polygon scanner is controlled within a known margin.

6. The LiDAR system of claim 5 further comprising:
an optical filter between at least one of the one or more lenses and the light detector.

7. The LiDAR system of claim 6 , wherein the optical filter is a bandpass filter with a pass band encompassing a frequency of the pulse signal.

8. The LiDAR system of claim 1 , wherein the coupling optic includes a first aspherical lens and a second aspherical lens.

9. The LiDAR system of claim 8 , wherein a first multi-layer bandpass film is deposited on a plano surface of the first aspherical lens, and wherein a second multi-layer bandpass film is deposited on a plano surface of the second aspherical lens.

10. The LiDAR system of claim 1 , wherein the light detector is placed onto an end facet of the fiber to directly receive the returned light pulse from the end of the fiber core opposite the receiving end.

11. The LiDAR system of claim 1 , wherein the light detector is an avalanche photodiode.

12. The LiDAR system of claim 1 , wherein the field lens is a part of a field lens group, wherein the field lens group is positioned along the optical receive path, and wherein the field lens group is configured to redirect the returned light pulse.

13. A method, comprising:
transmitting, using a light source, a pulse signal;
steering, using one or more mirrors, a returned light pulse associated with the transmitted pulse signal along an optical receive path wherein the one or more mirrors include a polygon scanner configured to rotate about an axis;
redirecting, using a field lens positioned along the optical receive path, the returned light pulse into a fiber having a fiber core, wherein the fiber is configured to receive the redirected returned light pulse to within a predetermined area, along a unidirectional receive path;
receiving, using a receiving end of the fiber core, wherein the fiber core has a cross-sectional area that is equal to or greater than the predetermined area, the returned light pulse from the field lens along the optical receive path; and
receiving, using a light detector, the returned light pulse from an end of the fiber core opposite the receiving end, wherein the light detector receives the returned light pulse through a coupling optic wherein a detecting area of the light detector is approximately equal to or smaller than the cross-sectional area of the fiber core.

14. The method of claim 13 , wherein the field lens is configured to reduce walk-off error associated with the one or more mirrors.

15. The method of claim 13 , wherein the light detector comprises an avalanche photodiode.

16. The method of claim 15 , wherein the polygon scanner is also configured to direct the transmitted pulse signal from the LiDAR system.

17. The method of claim 13 , wherein the one or more mirrors include a parabolic mirror.

18. The method of claim 13 , wherein a variation in the speed of rotation of the polygon scanner is controlled within a known margin.

19. The method of claim 13 , further comprising: positioning an optical filter between the coupling optic and the light detector.

20. The LiDAR system of claim 1 , wherein the light detector directly receives the returned light pulse if the light detector has a larger area than the cross-sectional area of the fiber core.

Assignees

• Innovusion Ireland Ltd
• Seyond Inc

Inventors

• Li Jim
• Li Yimin
• Bao Junwei

Classifications

• G01S7/4818

  using optical fibres · CPC title

• G01S17/10

  using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) · CPC title

• G01S7/4816

  of receivers alone · CPC title

• G01S17/89 Primary

  for mapping or imaging · CPC title