Electronically scanned light ranging device having multiple emitters sharing the field of view of a single sensor

• US 10,527,725 B2
• Filed: 07/05/2018
• Issued: 01/07/2020
• Est. Priority Date: 07/05/2017
• Status: Active Grant

• Current Assignee: Ouster, Inc.
• Original Assignee: Ouster, Inc.
• Inventors: Pacala, Angus, Frichtl, Mark
• Primary Examiner(s): Ratcliffe, Luke D
• Application Number:
  US16/028,154
• Publication Number:
  US 20190011561A1
• Time in Patent Office: 551 Days
• CPC Class Codes: B81B 5/00 Devices comprising elements which are movable in relation to each other, e.g. comprising slidable or rotatable elements
• 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 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 7/4815 using multiple transmitters
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01S 7/4863 Detector arrays, e.g. charge-transfer gates
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating
• CPC Class Codes: G02B 26/08 for controlling the direction of light in light guides G02B6/35
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 26/105 with one or more pivoting mirrors or galvano-mirrors G02B26/101 takes precedence
• CPC Class Codes: G02B 27/30 Collimators
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: G02B 3/0068 arranged in a single integral body or plate, e.g. laminates or hybrid structures with other optical elements G02B5/1885, G02B17/002, G02B30/27 take precedence
• CPC Class Codes: G06V 20/58 Recognition of moving objects or obstacles, e.g. vehicles or pedestrians; Recognition of traffic objects, e.g. traffic signs, traffic lights or roads
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• 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: H01S 5/183 : having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
• CPC Class Codes: H01S 5/4075 : Beam steering

Abstract

Embodiments describe a solid state electronic scanning LIDAR system that includes a scanning focal plane transmitting element and a scanning focal plane receiving element whose operations are synchronized so that the firing sequence of an emitter array in the transmitting element corresponds to a capturing sequence of a photosensor array in the receiving element. During operation, the emitter array can sequentially fire one or more light emitters into a scene and the reflected light can be received by a corresponding set of one or more photosensors through an aperture layer positioned in front of the photosensors. Each light emitter can correspond with an aperture in the aperture layer, and each aperture can correspond to a photosensor in the receiving element such that each light emitter corresponds with a specific photosensor in the receiving element.

Claims

1. A solid state optical system for performing distance measurements, the solid state optical system comprising:

a first illumination source comprising a first plurality of light emitters aligned to project discrete, nonoverlapping beams of light into a field external to the optical system according to a first illumination pattern;

a second illumination source comprising a second plurality of light emitters aligned to project discrete, nonoverlapping beams of light into the field according to a second illumination pattern having a same size and geometry as the first illumination pattern; and

a light detection module including a plurality of photosensors configured to detect photons emitted from the first and second illumination sources and reflected from surfaces within the field, wherein the plurality of photosensors are aligned according to a sensing pattern that has substantially the same size and geometry as the first and second illumination patterns such that each photosensor in the plurality of photosensors has a field-of-view that overlaps with a field-of-view of one emitter from the first plurality of light emitters and one emitter from the second plurality of light emitters;

wherein the first and second pluralities of light emitters and the plurality of photosensors operate in synchronization such that when one or more light emitters are activated, a corresponding one or more of the photosensors are read.

2. The optical system set forth in claim 1 further comprising emitter firing circuitry coupled to the first and second pluralities of light emitters and configured to execute a plurality of image capture periods where, for each image capture period the emitter firing circuitry sequentially fires a subset of emitters from the first plurality of light emitters followed by a subset of emitters from the second plurality of light emitters until the first and second illumination patterns are generated.

3. The optical system set forth in claim 2 wherein, for each image capture period, each subset of emitters from the first plurality of light emitters fired by the emitter firing circuitry represents a distinct portion of the first illumination pattern and each subset of emitters from the second plurality of light emitters fired subsequent to the subset of emitters from the first plurality of light emitters represents a distinct portion of the second illumination pattern that corresponds to the distinct portion of the first illumination pattern.

4. The optical system set forth in claim 3 further comprising sensor readout circuitry coupled to the plurality of photosensors and configured to synchronize the readout of individual photosensors within the plurality of photosensors concurrently with the firing of corresponding light emitters from the first and second light plurality of light emitters.

5. The optical system set forth in claim 1 wherein the plurality of photosensors is disposed between the first and second pluralities of light emitters.

6. The optical system set forth in claim 1 wherein each discrete spot in the first illumination pattern and its corresponding discrete spot in the second illumination pattern represent non-overlapping portions of the field of view of the corresponding sense channel.

7. The optical system set forth in claim 6 wherein the light detection module further includes an aperture layer including a plurality of apertures, the aperture layer and the plurality of photosensors being arranged to form a plurality of sense channels with each sense channel in the plurality of sense channels including one photosensor from the plurality of photosensors, a first aperture in the aperture layer that defines a first field of view for the photosensor in the channel and a second aperture in the aperture layer that defines a second field of view for the photosensor in the channel, wherein the first field of view is aligned with a field of view of an emitter in the first illumination source and the second field of view is aligned with a field of view of an emitter in the second illumination source.

8. The optical system set forth in claim 7 wherein each sense channel includes a first micro-lens aligned with the first aperture and a second micro-lens aligned with the second aperture.

9. The optical system set forth in claim 1 wherein each discrete spot in the first illumination pattern overlaps with and is substantially the same size as its corresponding spot in the second illumination pattern.

10. The optical system set forth in claim 1 further comprising a third illumination source comprising a third plurality of light emitters aligned to project discrete beams of light into a field external to the optical system according to a third illumination pattern having a same size and geometry as the first illumination pattern;

and

wherein the plurality of photosensors is further configured to detect photons emitted from the third illumination source and the third plurality of light emitters operates in synchronization with the first and second plurality of light emitters and the plurality of photosensors such that when one or more light emitters are activated, a corresponding one or more of the photosensors are read.

11. The optical system set forth in claim 1 wherein the first and second pluralities of light emitters and the plurality of photosensors operate in synchronization such that when a column of light emitters are activated, a corresponding column of the photosensors are read.

12. A solid state optical system for performing distance measurements, the solid state optical system comprising:

a first light emission module including a first bulk transmitter optic and a first illumination source comprising a first plurality of light emitters aligned to project discrete beams of light through the first bulk transmitter optic into a field external to the optical system according to a first illumination pattern;

a second light emission module including a second bulk transmitter optic and a second illumination source comprising a second plurality of light emitters aligned to project discrete beams of light through the second bulk transmitter optic into the field according to a second illumination pattern having a same size and geometry as the first illumination pattern; and

a light detection module including a bulk receiver optic, an aperture layer including a plurality of apertures, and a photosensor layer including a plurality of photosensors configured to detect photons emitted from the first and second illumination sources and reflected from surfaces within the field through the bulk receiver optic, wherein the aperture layer and the photosensor layer are arranged to form a plurality of sense channels, each sense channel including an aperture from the aperture layer and a photosensor from the photosensor layer and having a field-of-view that overlaps with a field-of-view of one emitter from the first plurality of light emitters and one emitter from the second plurality of light emitters;

wherein the first and second pluralities of light emitters and the plurality of photosensors operate in synchronization such that when one or more light emitters are activated, a corresponding ones of the photosensors are read.

13. The optical system set forth in claim 12 further comprising:

emitter firing circuitry coupled to the first and second pluralities of light emitters and configured to execute a plurality of image capture periods where, for each image capture period the emitter firing circuitry sequentially fires a subset of emitters from the first plurality of light emitters followed by a subset of emitters from the second plurality of light emitters until the first and second illumination patterns are generated; and

sensor readout circuitry coupled to the plurality of photosensors and configured to synchronize the readout of individual photosensors within the plurality of photosensors concurrently with the firing of corresponding light emitters from the first and second plurality of light emitters.

14. The optical system set forth in claim 13 wherein, for each image capture period, each subset of emitters from the first plurality of light emitters fired by the emitter firing circuitry represents a distinct portion of the first illumination pattern and each subset of emitters from the second plurality of light emitters fired subsequent to the subset of emitters from the first plurality of light emitters represents a distinct portion of the second illumination pattern that corresponds to the distinct portion of the first illumination pattern.

15. The optical system set forth in claim 12 wherein each discrete spot in the first illumination pattern and its corresponding discrete spot in the second illumination pattern represent non-overlapping portions of the field of view of the corresponding sense channel.

16. The optical system set forth in claim 12 wherein each discrete spot in the first illumination pattern overlaps with and is substantially the same size as its corresponding spot in the second illumination pattern.

17. A solid state optical system for performing distance measurements, the solid state optical system comprising:

a light detection system comprising 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 the photosensor layer are arranged to form a plurality of sense channels having a sensing pattern with each sense channel in the plurality of sense channels defining a discrete, non-overlapping field-of-view beyond a threshold distance in a field ahead of the light detection system and including an aperture from the aperture layer and a photosensor from the photosensor layer;

a light emission system comprising a first bulk transmitter optic, a first plurality of light emitters aligned to project discrete beams of light through the first bulk transmitter optic into the field according to a first illumination pattern, a second bulk transmitter optic, and a second plurality of light emitters aligned to project discrete beams of light through the second bulk transmitter optic into the field according to a second illumination pattern having a same size and geometry as the first illumination pattern, wherein the first and second illumination patterns are aligned such that one discrete beam from the first illumination pattern and one discrete beam from the second illumination pattern falls within the field-of-view of each sense channel in the plurality of sense channels;

emitter firing circuitry coupled to the first and second pluralities of light emitters and configured to execute a plurality of image capture periods where, for each image capture period the emitter firing circuitry sequentially fires a subset of emitters from the first plurality of light emitters followed by a subset of emitters from the second plurality of light emitters until the first and second illumination patterns are generated; and

sensor scanning circuitry coupled to the plurality of photosensors and configured to synchronize the readout of individual photosensors within the plurality of photosensors concurrently with the firing of corresponding emitters within the first and second pluralities of light emitters.

18. The optical system set forth in claim 17 wherein each discrete spot in the first illumination pattern and its corresponding discrete spot in the second illumination pattern represent non-overlapping portions of the field of view of the corresponding sense channel.

19. The optical system set forth in claim 18 wherein each sense channel includes a first micro-lens aligned with a field of view of a discrete beam in the first illumination pattern and a second micro-lens aligned with a field of view of a discrete beam in the second illumination pattern.

20. The optical system set forth in claim 17 wherein each discrete spot in the first illumination pattern overlaps with and is substantially the same size as its corresponding spot in the second illumination pattern.

21. The optical system set forth in claim 17 wherein each photosensor in the plurality of photosensors includes a plurality of SPADS, and each light emitter in the first and second pluralities of light emitters is a vertical-cavity surface-emitting laser (VCSEL).

22. A solid state optical system for performing distance measurements, the solid state optical system comprising:

a first illumination source comprising a first plurality of light emitters aligned to project discrete beams of light into a field external to the optical system according to a first illumination pattern;

a second illumination source comprising a second plurality of light emitters aligned to project discrete beams of light into the field according to a second illumination pattern having a same size and geometry as the first illumination pattern; and

a light detection module including a plurality of photosensors configured to detect photons emitted from the first and second illumination sources and reflected from surfaces within the field, wherein each photosensor in the plurality of photosensors has a field-of-view that overlaps with a field-of-view of one emitter from the first plurality of light emitters and one emitter from the second plurality of light emitters;

wherein the first and second pluralities of light emitters and the plurality of photosensors operate in synchronization such that when one or more light emitters are activated, a corresponding one or more of the photosensors are read, and

wherein the light detection module further includes an aperture layer including a plurality of apertures, the aperture layer and the plurality of photosensors being arranged to form a plurality of sense channels with each sense channel in the plurality of sense channels including one photosensor from the plurality of photosensors, a first aperture in the aperture layer that defines a first field of view for the photosensor in the channel and a second aperture in the aperture layer that defines a second field of view for the photosensor in the channel, wherein the first field of view is aligned with a field of view of an emitter in the first illumination source and the second field of view is aligned with a field of view of an emitter in the second illumination source.