LIDAR receiver using a waveguide and an aperture

• US 10,698,088 B2
• Filed: 08/01/2017
• Issued: 06/30/2020
• Est. Priority Date: 08/01/2017
• Status: Active Grant

• Current Assignee: Waymo LLC (Alphabet Inc.)
• Original Assignee: Waymo LLC (Alphabet Inc.)
• Inventors: Droz, Pierre-Yves, Hutchison, David Neil, Shepard, Ralph Hamilton
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US15/665,796
• Publication Number:
  US 20190041498A1
• Time in Patent Office: 1,064 Days
• Field of Search: 356 401
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 7/4816 of receivers alone
• CPC Class Codes: G01S 7/4818 using optical fibres
• CPC Class Codes: G01S 7/4863 Detector arrays, e.g. charge-transfer gates
• CPC Class Codes: G02B 6/003 Lens or lenticular sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/4214 the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device G02B6/4246 takes precedence
• CPC Class Codes: G02B 6/4298 coupling with non-coherent light sources and/or radiation detectors, e.g. lamps, incandescent bulbs, scintillation chambers

Abstract

The present disclosure relates to limitation of noise on light detectors using an aperture. One example implementation includes a system. The system includes a lens disposed relative to a scene. The lens focuses light from the scene. The system also includes an opaque material that defines an aperture. The system also includes a waveguide having a first side that receives light focused by the lens and transmitted through the aperture. The waveguide guides the received light toward a second side of the waveguide opposite to the first side. The waveguide has a third side extending between the first side and the second side. The system also includes a mirror that reflects the guided light toward the third side of the waveguide. The system also includes an array of light detectors that detects the reflected light propagating out of the third side.

Claims

1. A system comprising:

a lens disposed relative to a scene, wherein the lens focuses light from the scene;

an opaque material that defines an aperture;

a waveguide having a first side that receives light focused by the lens and transmitted through the aperture, wherein the waveguide guides at least a portion of the received light toward a second side of the waveguide opposite to the first side by total internal reflection or frustrated total internal reflection, and wherein the waveguide has a third side extending between the first side and the second side;

a mirror disposed along a path of the guided light, wherein the mirror reflects the guided light toward the third side of the waveguide; and

an array of light detectors that detects the reflected light propagating out of the third side of the waveguide.

2. The system of claim 1, wherein the mirror is tilted at an offset angle relative to the first side of the waveguide.

3. The system of claim 1, wherein the second side of the waveguide is tilted toward the third side, and wherein the mirror is disposed along the second side of the waveguide.

4. The system of claim 1, further comprising:

a first substrate, wherein the third side of the waveguide is disposed along a surface of the first substrate;

a second substrate; and

an adhesive that surrounds the waveguide, wherein the adhesive couples the first substrate to the second substrate.

5. The system of claim 4, wherein the waveguide comprises a photoresist material having an index of refraction greater than a given index of refraction of the adhesive.

6. The system of claim 4, wherein the adhesive further couples the opaque material to the first substrate and the second substrate.

7. The system of claim 6, further comprising:

a third substrate disposed on the opaque material and positioned between the opaque material and the lens, wherein the adhesive extends through the aperture defined by the opaque material to couple the third substrate with the first substrate and the second substrate.

8. The system of claim 7, further comprising:

a light filter disposed on the third substrate, wherein the light filter attenuates the focused light propagating toward the aperture.

9. The system of claim 4, further comprising:

a second aperture defined by the opaque material, wherein the waveguide is a first waveguide;

a second waveguide disposed on the first substrate, wherein the second waveguide receives and guides a portion of the focused light that is transmitted through the second aperture, and wherein the adhesive further surrounds the second waveguide;

a second mirror that reflects the guided portion of the light out of the second waveguide; and

a second array of light detectors that detects the reflected light propagating out of the second waveguide.

10. A method comprising:

focusing, via a lens disposed relative to a scene, light from the scene;

transmitting the focused light through an aperture defined within an opaque material;

receiving, at a first side of a waveguide, the focused light transmitted through the aperture;

guiding, by the waveguide, at least a portion of the received light toward a second side of the waveguide by total internal reflection or frustrated total internal reflection;

reflecting, via a mirror, the guided light toward a third side of the waveguide, wherein the third side extends between the first side and the second side; and

detecting, at an array of light detectors, the reflected light propagating out of the third side of the waveguide.

11. The method of claim 10, further comprising:

combining outputs from the light detectors in the array based on the light detectors in the array being connected in parallel to one another.

12. A light detection and ranging (LIDAR) device comprising:

a LIDAR transmitter that illuminates a scene; and

a LIDAR receiver that receives light reflected by one or more objects within the scene, wherein the LIDAR receiver comprises;

a lens that focuses light from the scene;

an opaque material that defines an aperture;

a waveguide having a first side that receives light focused by the lens and transmitted through the aperture, wherein the waveguide guides at least a portion of the received light toward a second side of the waveguide opposite to the first side by total internal reflection or frustrated total internal reflection, and wherein the waveguide has a third side extending between the first side and the second side;

a mirror disposed along a path of the guided light, wherein the mirror reflects the guided light toward the third side of the waveguide; and

an array of light detectors that detects the light reflected by the mirror and propagating out of the third side of the waveguide.

13. The LIDAR device of claim 12, wherein the array of light detectors comprises a plurality of single photon avalanche diodes (SPADs).

14. The LIDAR device of claim 12, wherein the light detectors in the array are connected in parallel with one another.

15. The LIDAR device of claim 12, wherein the LIDAR receiver further comprises:

a first substrate, wherein the third side of the waveguide is disposed along a surface of the first substrate;

a second substrate; and

an adhesive that surrounds the waveguide, wherein the adhesive couples the first substrate to the second substrate.

16. The LIDAR device of claim 15, wherein the waveguide comprises a material having an index of refraction greater than a given index of refraction of the adhesive.

17. The LIDAR device of claim 16, wherein the LIDAR receiver further comprises:

a third substrate disposed on the opaque material and positioned between the opaque material and the lens, wherein the adhesive is a first adhesive; and

a second adhesive that also has the given index of refraction of the first adhesive, wherein the second adhesive extends through the aperture defined by the opaque material to couple the third substrate to;

the first substrate, the second substrate, and the first adhesive.

18. The LIDAR device of claim 17, wherein the second adhesive further couples the opaque material to the first substrate and the second substrate.

19. The LIDAR device of claim 17, wherein the LIDAR receiver further comprises:

a light filter disposed on the third substrate, wherein the light filter attenuates the focused light propagating toward the aperture.

20. The LIDAR device of claim 15, wherein the LIDAR receiver further comprises:

a second aperture defined by the opaque material, wherein the waveguide is a first waveguide;

a second waveguide disposed on the first substrate, wherein the second waveguide receives and guides a portion of the focused light that is transmitted through the second aperture, wherein the adhesive also surrounds the second waveguide;

a second mirror that reflects the guided portion of the light out of the second waveguide; and

a second array of light detectors that detects the reflected light propagating out of the second waveguide.