Integrated Illumination And Detection For LIDAR Based 3-D Imaging

• US 20170269215A1
• Filed: 01/31/2017
• Published: 09/21/2017
• Est. Priority Date: 03/19/2016
• Status: Active Grant

• Current Assignee: Velodyne Lidar USA, Inc. (Ouster, Inc.)
• Original Assignee: Velodyne LiDAR, Inc. (Ouster, Inc.)
• Inventors: Hall, David S., Kerstens, Pieter J., Rekow, Mathew Noel
• Granted Patent: US 10,018,726 B2
• Time in Patent Office: Days
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver

Abstract

Methods and systems for performing three dimensional LIDAR measurements with a highly integrated LIDAR measurement device are described herein. In one aspect, the illumination source, detector, and illumination drive are integrated onto a single printed circuit board. In addition, in some embodiments, the associated control and signal conditioning electronics are also integrated onto the common printed circuit board. Furthermore, in some embodiments, the illumination drive and the illumination source are integrated onto a common Gallium Nitride substrate that is independently packaged and attached to the printed circuit board. In another aspect, the illumination light emitted from the illumination source and the return light directed toward the detector share a common optical path within the integrated LIDAR measurement device. In some embodiments, the return light is separated from the illumination light by a beam splitter. In some other embodiments, the optical design avoids losses associated with a beam splitter.

Claims

1. An integrated light detection and ranging (LIDAR) device, comprising:

an illumination source mounted to a printed circuit board, the illumination source configured to generate a measurement pulse of illumination light;

a detector mounted to the printed circuit board, the detector configured to detect a return pulse of light and generate an output signal indicative of the detected return pulse, wherein the return pulse is an amount of the measurement pulse reflected from a location in a three dimensional environment illuminated by the corresponding measurement pulse, wherein the measurement pulse of illumination light and the return pulse share a common optical path over a distance within the integrated LIDAR device;

an illumination driver mounted to the printed circuit board, the illumination driver electrically coupled to the illumination source and configured to provide an amount of electrical power to the illumination source that causes the illumination source to emit the measurement pulse of illumination light;

an amount of analog signal conditioning electronics mounted to the printed circuit board, the analog signal conditioning electronics configured to amplify the output signal generated by the detector;

an analog to digital converter mounted to the printed circuit board, the analog to digital converter configured to convert the amplified output signal to a digital signal; and

a computing system configured to;

receive the digital signal indicative of the detected amount of light; and

determine a time of flight of the measurement pulse from the LIDAR device to the measured location in the three dimensional environment and back to the LIDAR device based on the digital signal.

2. The LIDAR device of claim 1, wherein the illumination source and the illumination driver are integrated onto a single Gallium Nitride based substrate that is mounted to the printed circuit board.

3. The LIDAR device of claim 1, wherein the return pulse of light and the illumination pulse are separated from the common optical path by a beam splitter within the LIDAR device.

4. The LIDAR device of claim 1, wherein the detector includes an active sensing surface area and a transparent aperture within the field of view of the detector.

5. The LIDAR device of claim 4, wherein the transparent aperture is a void through the detector.

6. The LIDAR device of claim 5, wherein the illumination source emits the measurement pulse of illumination light through the transparent aperture in the detector such that the measurement pulse of illumination light is within the field of view of the detector.

7. The LIDAR device of claim 1, further comprising:

an active optical element having a selectable index of refraction located in the common optical path, wherein the active optical element in a first state directs the return pulse to the detector, and wherein the active optical element in a second state directs the measurement beam of illumination light into the common optical path.

8. The LIDAR device of claim 1, further comprising:

a first optical element located in the common optical path, the first optical element configured to focus the return pulse of light onto the detector;

a second optical element located in the common optical path, the second optical element configured to direct the measurement beam of illumination light into the common optical path, wherein the illumination source is located outside the field of view of the detector.

9. The LIDAR device of claim 1, further comprising:

a mirror element located in the common optical path, wherein the mirror element includes a transparent aperture within a portion of the mirror that is within the field of view of the detector, and wherein the illumination source emits the measurement beam of illumination light through the transparent aperture into the common optical path.

10. The LIDAR device of claim 1, wherein the illumination source is located in the shared optical path within a field of view of the detector.

11. The LIDAR device of claim 10, wherein the illumination source is embedded in an optical element located in the shared optical path within the field of view of the detector.

12. The LIDAR device of claim 1, further comprising:

an optical fiber element optically coupled between the illumination source located outside a field of view of the detector and a mirror element located in the common optical path within the field of view of the detector.

13. The LIDAR device of claim 3, further comprising:

a first polarization control element located in a beam path of the measurement pulse of illumination light, wherein in a first state the first polarization control element causes the measurement pulse of illumination light to pass through the first polarization control element, and wherein in a second state the first polarization control element causes the return pulse to be reflected from the first polarization control element toward the detector.

14. The LIDAR device of claim 13, further comprising:

a second polarization control element located in a beam path of the return pulse, wherein the second polarization control element controls an amount of the return pulse that is directed to the detector.

15. A method comprising:

generating a measurement pulse of illumination light by an illumination source mounted to a printed circuit board;

detecting a return pulse of light by a detector mounted to the printed circuit board, wherein the return pulse is an amount of the measurement pulse reflected from a location in a three dimensional environment illuminated by the corresponding measurement pulse, wherein the measurement pulse of illumination light and the return pulse share a common optical path over a distance within the integrated LIDAR device;

generating an output signal indicative of the detected return pulse;

providing an amount of electrical power to the illumination source by an illumination driver mounted to the printed circuit board that causes the illumination source to emit the measurement pulse of illumination light;

amplifying the output signal by an amount of analog signal conditioning electronics mounted to the printed circuit board;

converting the amplified output signal to a digital signal by an analog to digital converter mounted to the printed circuit board; and

determining a time of flight of the measurement pulse from the LIDAR device to the measured location in the three dimensional environment and back to the LIDAR device based on the digital signal.

16. The method of claim 15, wherein the illumination source and the illumination driver are integrated onto a single Gallium Nitride based substrate that is mounted to the printed circuit board.

17. The method of claim 15, wherein the illumination source emits the measurement pulse of illumination light through a transparent aperture in an active surface of detector such that the measurement pulse of illumination light is within the field of view of the detector.

18. The method of claim 15, further comprising:

selecting an index of refraction of an active optical element located in the common optical path, wherein the index of refraction in a first state directs the return pulse to the detector, and wherein the index of refraction in a second state directs the measurement beam of illumination light into the common optical path.

19. The method of claim 15, further comprising:

focusing the return pulse of light onto the detector with a first optical element located in the common optical path;

directing the measurement beam of illumination light into the common optical path with a second optical element located in the common optical path, wherein the illumination source is located outside the field of view of the detector.

20. The method of claim 15, further comprising:

emitting the measurement beam of illumination light through a transparent aperture within a portion of a mirror element within a field of view of the detector.

21. The method of claim 15, wherein the illumination source is located in the shared optical path within a field of view of the detector.

22. The method of claim 15, further comprising:

optically coupling the illumination source located outside a field of view of the detector and a mirror element located in the common optical path within the field of view of the detector.

23. The method of claim 15, further comprising:

selecting a first polarization state of a first polarization control element located in a beam path of the measurement pulse of illumination light that causes the measurement pulse of illumination light to pass through the first polarization control element; and

selecting a second polarization state of the first polarization control element that causes the return pulse to be reflected from the first polarization control element toward the detector.

24. The method of claim 23, further comprising:

selecting a polarization state of a second polarization control element located in a beam path of the return pulse that controls an amount of the return pulse that is directed to the detector.

25. An integrated light detection and ranging (LIDAR) device, comprising:

an illumination source mounted to a printed circuit board, the illumination source configured to generate a measurement pulse of illumination light;

a detector mounted to the printed circuit board, the detector configured to detect a return pulse of light and generate an output signal indicative of the detected return pulse, wherein the return pulse is an amount of the measurement pulse reflected from a location in a three dimensional environment illuminated by the corresponding measurement pulse, wherein the measurement pulse of illumination light and the return pulse share a common optical path over a distance within the integrated LIDAR device;

an illumination driver mounted to the printed circuit board, the illumination driver electrically coupled to the illumination source and configured to provide an amount of electrical power to the illumination source that causes the illumination source to emit the measurement pulse of illumination light; and

a computing system configured to determine a time of flight of the measurement pulse from the LIDAR device to the measured location in the three dimensional environment and back to the LIDAR device based at least in part on output signal.

26. The LIDAR device of claim 25, wherein the illumination source and the illumination driver are integrated onto a single Gallium Nitride based substrate that is mounted to the printed circuit board.