Optical imaging transmitter with brightness enhancement

• US 10,222,475 B2
• Filed: 05/14/2018
• Issued: 03/05/2019
• Est. Priority Date: 05/15/2017
• Status: Active Grant

• Current Assignee: Ouster, Inc.
• Original Assignee: Ouster, Inc.
• Inventors: Pacala, Angus, Frichtl, Mark, Younge, Eric
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US15/979,235
• Publication Number:
  US 20180329065A1
• Time in Patent Office: 295 Days
• Field of Search: 356 401
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• 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 17/931 of land vehicles
• CPC Class Codes: G01S 7/4813 Housing arrangements
• CPC Class Codes: G01S 7/4815 using multiple transmitters
• CPC Class Codes: G01S 7/4816 of receivers alone
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01S 7/486 Receivers
• CPC Class Codes: G01S 7/4863 Detector arrays, e.g. charge-transfer gates
• CPC Class Codes: G01S 7/4865 Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak peak detection in noise, signal conditioning G01S7/487
• CPC Class Codes: G02B 27/0037 with diffracting elements G02B27/0056 takes precedence; holographic optical elements G02B5/32; zone systems G02B5/1876
• CPC Class Codes: G02B 27/0955 Lenses lenses per se G02B3/00
• CPC Class Codes: G02B 27/30 Collimators
• CPC Class Codes: G02B 27/46 Systems using spatial filters
• CPC Class Codes: G02B 5/205 Neutral density filters
• CPC Class Codes: H01L 27/1446 in a repetitive configuration
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H01L 31/02027 for devices working in avalanche mode
• CPC Class Codes: H01L 31/02162 : for filtering or shielding light, e.g. multicolour filters for photodetectors
• CPC Class Codes: H01L 31/02164 : for shielding light, e.g. light blocking layers, cold shields for infrared detectors
• CPC Class Codes: H01L 31/02165 : using interference filters, e.g. multilayer dielectric filters interference filters G02B5/28
• CPC Class Codes: H01L 31/02325 : the optical elements not being integrated nor being directly associated with the device
• CPC Class Codes: H01L 31/02327 : the optical elements being integrated or being directly associated to the device, e.g. back reflectors optical coatings H01L31/0216
• CPC Class Codes: H01L 31/107 : the potential barrier working in avalanche mode, e.g. avalanche photodiodes
• CPC Class Codes: H04B 10/503 : Laser transmitters
• CPC Class Codes: H04B 10/675 : for controlling the optical bandwidth of the input signal, e.g. spectral filtering
• CPC Class Codes: H04B 10/6973 : using noise matching networks
• CPC Class Codes: H04B 10/801 : using optical interconnects, e.g. light coupled isolators, circuit board interconnections

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.

Claims

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 at a location between the emitter and the bulk transmitter optic.

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 2 further comprising a light sensing module configured to detect photons emitted from the illumination source and reflected from surfaces within the field.

4. The optical system for performing distance measurements set forth in claim 3 wherein the light sensing module comprises:

a bulk receiver optic;

an aperture layer including a plurality of apertures;

a lens layer including a plurality of lenses; and

a photosensor layer including a plurality of photosensors, wherein the aperture layer, lens 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, a lens from the plurality of lenses 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.

5. The optical system for performing distance measurements set forth in claim 4 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.

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

7. The optical system for performing distance measurements set forth in claim 6 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.

8. The optical system for performing distance measurements set forth in claim 7, 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.

9. The optical system for performing distance measurements set forth in claim 7, 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.

10. The optical system for performing distance measurements set forth in claim 6 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.

11. The optical system for performing distance measurements set forth in claim 6 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.

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

13. The optical system for performing distance measurements set forth in claim 12 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.

14. The optical system for performing distance measurements set forth in claim 13 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.

15. The optical system for performing distance measurements set forth in claim 1 wherein the bulk transmitter optic comprises multiple aperture stops configured to reduce stray light emitted by the optical system.

16. An optical system for performing distance measurements, the optical system comprising:

a light emission 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 at a location between the emitter and the bulk transmitter optic; and

a light detection system comprising;

a bulk receiver optic configured to receive the discrete beams of light from the field; and

an optical assembly having a plurality of micro-optic receiver channels defining a plurality of discrete, non-overlapping fields of view in the field, the optical assembly comprising;

an aperture layer having a plurality of discrete apertures arranged along a focal plane of the bulk receiver optic;

an array of photosensors disposed behind the aperture layer; and

a plurality of lenses positioned between the aperture layer and the array of photosensors.

17. The optical system for performing distance measurements set forth in claim 16 wherein the bulk transmitter optic comprises one or more lenses configured as 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.

18. An optical system for performing distance measurements, the optical system comprising:

a stationary housing having an optically transparent window; and

a light ranging device disposed within the housing, the light ranging device comprising an optical transmitter coupled to a platform, the optical transmitter 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 at a location between the emitter and the bulk transmitter optic.

19. The optical system for performing distance measurements set forth in claim 18 wherein the light ranging device is a spinning light ranging device further comprising:

a motor disposed within the housing and operatively coupled to spin the light ranging device including the platform and optical transmitter within the housing;

a system controller disposed within the housing, the system controller configured to control the motor and to start and stop light detection operations of the light ranging device.

20. The optical system for performing distance measurements set forth in claim 18 wherein the bulk transmitter optic comprises one or more lenses configured as 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.