Lidar system

Patent metadata

Field	Value
Publication number	US-10557940-B2
Application number	US-201615364085-A
Country	US
Kind code	B2
Filing date	Nov 29, 2016
Priority date	Nov 30, 2015
Publication date	Feb 11, 2020
Grant date	Feb 11, 2020

Abstract

In one embodiment, a lidar system includes a light source configured to emit pulses of light and a scanner configured to scan at least a portion of the emitted pulses of light across a field of regard. The lidar system also includes a receiver configured to detect at least a portion of the scanned pulses of light scattered by a target located a distance from the lidar system.

First claim

What is claimed is:

1. A lidar system comprising:
a light source configured to emit pulses of light;
a scanner configured to scan at least a portion of the emitted pulses of light across a field of regard; and
a receiver comprising an avalanche photodiode (APD), a first comparator, a second comparator, and a time-to-digital converter (TDC), wherein the receiver is configured to detect at least a portion of the scanned pulses of light scattered by a target located a distance from the lidar system by generating, by the APD, an electrical-current signal corresponding to a received pulse of light, the received pulse of light corresponding to a pulse of light emitted by the light source, and wherein:
the first comparator is configured to produce a first electrical-edge signal when a voltage signal corresponding to the electrical-current signal generated by the APD rises above a first predetermined threshold voltage;
the second comparator is configured to produce a second electrical-edge signal when the voltage signal falls below a second predetermined threshold voltage; and
the TDC is configured to:
receive the first and second electrical-edge signals;
determine a first interval of time between emission of the pulse of light by the light source and receipt of the first electrical-edge signal; and
determine a second interval of time between emission of the pulse of light by the light source and receipt of the second electrical-edge signal.

2. The lidar system of claim 1 , further comprising a sensor head located remotely from the light source, wherein:
the sensor head comprises the scanner and the receiver; and
the sensor head is coupled to the light source by an optical link, wherein the optical link conveys the portion of the emitted pulses of light from the light source to the sensor head.

3. The lidar system of claim 2 , wherein the lidar system further comprises one or more additional sensor heads, wherein:
each of the additional sensor heads comprises a respective scanner and receiver; and
the light source is coupled to each of the additional sensor heads by a respective optical link which conveys a respective portion of the emitted pulses of light from the light source to each of the additional sensor heads.

4. The lidar system of claim 2 , wherein the lidar system is incorporated into a vehicle wherein the sensor head and one or more additional sensor heads of the lidar system are positioned to provide a greater than or equal to 30-degree view of an environment around the vehicle.

5. The lidar system of claim 1 , wherein the lidar system has a maximum range of greater than or equal to 50 meters.

6. The lidar system of claim 1 , wherein the field of regard comprises:
a horizontal field of regard greater than or equal to 25 degrees; and
a vertical field of regard greater than or equal to 5 degrees.

7. The lidar system of claim 1 , wherein the lidar system has a horizontal resolution of greater than or equal to 100 pixels and a vertical resolution of greater than or equal to 4 pixels.

8. The lidar system of claim 1 , wherein the lidar system is configured to generate point clouds at a rate between approximately 0.1 frames per second and approximately 1,000 frames per second.

9. The lidar system of claim 1 , wherein the light source comprises a pulsed laser diode.

10. The lidar system of claim 1 , wherein the light source comprises:
a seed laser configured to produce optical seed pulses; and
one or more optical amplifiers configured to amplify the optical seed pulses to produce the pulses of light emitted by the light source.

11. The lidar system of claim 10 , wherein the seed laser comprises a distributed-feedback (DFB) laser or a distributed-Bragg reflector (DBR) laser.

12. The lidar system of claim 1 , wherein the light source comprises a booster amplifier comprising a double-clad gain fiber comprising erbium dopants or erbium and ytterbium dopants.

13. The lidar system of claim 1 , wherein the light source comprises:
a plurality of laser diodes, wherein each laser diode is configured to produce light at a different operating wavelength; and
an optical multiplexer configured to combine the light produced by each laser diode into a single optical fiber.

14. The lidar system of claim 1 , wherein the light source is an eye-safe laser with an operating wavelength between approximately 1400 nm and approximately 1600 nm.

15. The lidar system of claim 1 , wherein the pulses of light emitted by the light source have pulse characteristics comprising:
an operating wavelength between approximately 1400 nm and approximately 1600 nm;
a pulse repetition frequency of less than or equal to 100 MHz;
a pulse duration of less than or equal to 20 nanoseconds; and
a duty cycle of less than or equal to 1%.

16. The lidar system of claim 15 , wherein the pulse characteristics further comprise:
a pulse energy of greater than or equal to 10 nanojoules;
a peak power of greater than or equal to 1 watt; and
an average power of less than or equal to 50 watts.

17. The lidar system of claim 1 , wherein the light source comprises an optical filter configured to transmit light at one or more operating wavelengths of the light source and attenuate light away from the transmitted wavelengths by at least 10 dB.

18. The lidar system of claim 1 , wherein the light source comprises an optical filter configured to reduce an amount of amplified spontaneous emission light produced by one or more optical amplifiers of the light source.

19. The lidar system of claim 1 , wherein the light source comprises a diode-pumped solid-state (DP S S) laser.

20. The lidar system of claim 1 , wherein the scanner comprises one or more mirrors, wherein each mirror is mechanically driven by a galvanometer scanner, a resonant scanner, a microelectromechanical systems (MEMS) device, or a voice coil motor.

21. The lidar system of claim 20 , wherein the scanner comprises:
a first mirror driven by a first galvanometer scanner that scans the first mirror along a first direction; and
a second mirror driven by a second galvanometer scanner that scans the second mirror along a second direction substantially orthogonal to the first direction.

22. The lidar system of claim 20 , wherein the scanner comprises:
a first mirror driven by a resonant scanner that scans the first mirror along a first direction; and
a second mirror driven by a galvanometer scanner that scans the second mirror along a second direction substantially orthogonal to the first direction.

23. The lidar system of claim 1 , wherein the scanner comprises two mirrors driven synchronously, wherein the synchronously driven mirrors trace out a scan pattern that comprises substantially straight lines.

24. The lidar system of claim 1 , wherein the scanner comprises a mirror driven by two actuators configured to scan the mirror along two substantially orthogonal directions.

25. The lidar system of claim 1 , wherein the scanner comprises a mirror configured to be scanned along two axes, wherein motion along each axis is provided by two actuators arranged in a push-pull configuration.

26. The lidar system of claim 1 , wherein the receiver further comprises a transimpedance amplifier (TIA) and a voltage-gain circuit, wherein the TIA and voltage-gain circuit are configured to receive the electrical-current signal from the APD and produce the voltage signal that cor

Assignees

• Luminar Tech Inc

Inventors

• Eichenholz Jason M
• Russell Austin K
• Campbell Scott R
• Villeneuve Alain
• Cleye Rodger W
• Lachapelle Joseph G
• Weed Matthew D
• Martin Lane A
• Gaalema Stephen D

Classifications

• H01S3/1608

  erbium · CPC title

• H01S3/0078

  Frequency filtering · CPC title

• H01S3/08086

  Multiple-wavelength emission · CPC title

• G01S17/89

  for mapping or imaging · CPC title

• G01S7/484

  Transmitters · CPC title