Optical imaging transmitter with brightness enhancement

Patent metadata

Field	Value
Publication number	US-10663586-B2
Application number	US-201916245909-A
Country	US
Kind code	B2
Filing date	Jan 11, 2019
Priority date	May 15, 2017
Publication date	May 26, 2020
Grant date	May 26, 2020

Abstract

Embodiments describe optical imagers that include one or more micro-optic components. Some imagers can be passive imagers that include a light detection system for receiving ambient light from a field. Some imagers can be active imagers that include a light emission system in addition to the light detection system. The light emission system can be configured to emit light into the field such that emitted light is reflected off surfaces of an object in the field and received by the light detection system. In some embodiments, the light detection system and/or the light emission system includes micro-optic components for improving operational performance.

First claim

What is claimed is:

1. An optical system for performing distance measurements, the optical system comprising:
a bulk transmitter optic;
an illumination source comprising a plurality of light emitters aligned to project discrete beams of light through the bulk transmitter optic into a field ahead of the optical system; and
a micro-optic channel array disposed between the illumination source and the bulk transmitter optic, the micro-optic channel array defining a plurality of micro-optic channels, each micro-optic channel including a micro-optic lens spaced apart from a light emitter from the plurality of light emitters with the micro-optic lens being configured to receive a light cone from the light emitter and generate a reduced-size spot image of the emitter at a focal point displaced from the emitter.

2. The optical system for performing distance measurements set forth in claim 1 wherein the bulk transmitter optic comprises one or more lenses configured as an image space telecentric lens in which the discrete beams of light output from the illumination source through the micro-optic channel array are parallel to each other.

3. The optical system for performing distance measurements set forth in claim 1 wherein the micro-optic channel array is formed on a monolithic structure.

4. The optical system for performing distance measurements set forth in claim 1 wherein the micro-optic channel array includes an aperture layer comprising a plurality of apertures and, for each micro-optic channel in the plurality of micro-optics channels, the reduced-spot image is formed within an aperture in the plurality of apertures.

5. The optical system for performing distance measurements set forth in claim 4 wherein the aperture layer comprises a reflective or opaque layer and each aperture in the plurality of apertures comprises a pinhole formed through the reflective or opaque layer.

6. The optical system for performing distance measurements set forth in claim 1 wherein a focal plane of the bulk transmitter optic coincides with the reduced-size spot images.

7. The optical system for performing distance measurements set forth in claim 1 further comprising a light sensing module configured to detect photons emitted from the illumination source and reflected from surfaces within the field.

8. The optical system for performing distance measurements set forth in claim 7 wherein the light sensing module comprises:
a bulk receiver optic;
an aperture layer including a plurality of apertures; and
a photosensor layer including a plurality of photosensors, wherein the aperture layer and photosensor layer are arranged to form a plurality of receiver channels with each receiver channel in the plurality of receiver channels including an aperture from the plurality of apertures and a photosensor from the plurality of photosensors and being configured to communicate light incident from the bulk receiving optic to the photosensor of the receiver channel.

9. The optical system for performing distance measurements set forth in claim 8 wherein each light emitter in the plurality of light emitters comprises a vertical-cavity surface-emitting laser (VCSEL) and each photosensor in the plurality of photosensors comprises a plurality of single-photon avalanche diodes (SPADs).

10. The optical system for performing distance measurements set forth in claim 8 wherein the light sensing module further comprises a lens layer including a plurality of lenses and wherein each receiver channel in the plurality of receiver channels includes a lens from the plurality of lenses.

11. The optical system for performing distance measurements set forth in claim 10 wherein the light sensing module further comprises an optical filter optical filter between the aperture layer and the photosensor layer, the optical filter configured to pass a narrow band of radiation that includes the operating wavelength of the plurality of emitters to the plurality of photosensors while blocking radiation outside the band.

12. The optical system for performing distance measurements set forth in claim 8 wherein the illumination source is configured to selectively project the discrete beams of light through the bulk transmitter optic according to an illumination pattern that matches, in size and geometry across a range of distances from the system, the fields of view of the receiver channels.

13. The optical system for performing distance measurements set forth in claim 1 wherein the micro-optic lens for each channel is positioned within the channel to receive a light cone from a light emitter and configured to generate a reduced-size real spot image of the emitter at a focal point between the micro-optic lens and the bulk transmitter optic.

14. The optical system for performing distance measurements set forth in claim 13 wherein the micro-optic lens for each channel includes a first optical surface with an optical power on a side facing the light emitter and a second optical surface with an optical power on an opposing side facing away from the light emitter and wherein the reduced-size real spot image of the emitter is formed at a focal point after the first and second optical surfaces.

15. The optical system for performing distance measurements set forth in claim 14 wherein a divergence of the light cone from the light emitter is less than a divergence of a light cone from the second optical surface of the micro-optic lens for generating the reduced-size real spot image.

16. The optical system for performing distance measurements set forth in claim 14 wherein the micro-optic lens is separated from the illumination source to define an open space between the micro-optic lens and the illumination source.

17. The optical system for performing distance measurements set forth in claim 13 wherein the micro-optic lens for each channel includes an optical surface with an optical power on a side facing away from the light emitter and wherein the reduced-size real spot image of the emitter is formed at a focal point after the optical surface.

18. The optical system for performing distance measurements set forth in claim 13 wherein the optical surface includes a plurality of convex lenses positioned on a substrate, the substrate having a first surface upon which the optical surface is disposed and a second surface opposite of the first surface that is directly attached to a surface of the illumination source.

19. The optical system for performing distance measurements set forth in claim 1 wherein the micro-optic lens for each channel is positioned within the channel to receive a light cone from a light emitter and configured to generate a reduced-size virtual spot image of the emitter.

20. The optical system for performing distance measurements set forth in claim 19 wherein the micro-optic lens for each channel includes an optical surface with an optical power on a side facing away from the light emitter and wherein the reduced-size virtual spot image of the emitter is formed at a focal point within the respective channel.

21. The optical system for performing distance measurements set forth in claim 20 wherein the optical surface includes a plurality of concave surfaces formed on substrate, the substrate having a first surface upon which the optical surface is disposed and a second surface opposite of the first surface that is directly attached to a surface of the illumination source.

22. The optical system for performing distance measurements set forth in

Assignees

• Ouster Inc

Inventors

• Pacala Angus
• Frichtl Mark
• Younge Eric

Classifications

• G01S7/4815

  using multiple transmitters · CPC title

• G01S7/4817

  relating to scanning · CPC title

• G01S17/10 Primary

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

• H04B10/6973

  using noise matching networks · CPC title

• G01S7/4813

  Housing arrangements · CPC title