ACTUATED OPTICAL ELEMENT FOR LIGHT BEAM SCANNING DEVICE

• US 20160245919A1
• Filed: 02/20/2015
• Published: 08/25/2016
• Est. Priority Date: 02/20/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Kalscheur, Micah P., Nawasra, Jawad
• Granted Patent: US 10,107,914 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 7/4814 of transmitters alone
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01S 7/51 Display arrangements

Abstract

A light beam scanning device includes a lens element assembly which dynamically adjusts a divergence of the beam. The lens element assembly can include multiple lens elements, one or more of which translates parallel to the light beam to adjust beam divergence. Divergence adjustment can include adjusting the beam divergence along one or more cross sectional axes of the beam. Beam divergence can be adjusted between consecutive scans, during a scan, etc. Beam divergence can be adjusted based on the field of view and scan rate. Beam divergence adjustment can enable dynamic adjustment of the spot size of the beam, which can enable the apparatus to adjust between scanning a wide divergence beam to detect objects in a scene and scanning a narrow divergence beam to generate detailed point clouds of the detected objects. Beam divergence adjustment can enable adjustment of reflection point intensity, enabling detection of low-reflectivity objects.

Claims

1. An apparatus, comprising:

a light beam scanning device configured to scan a light beam, within a scan range, over a scene that is within a field of view of the scan range and generate an image map of at least a portion of the scene, based at least in part upon a time of flight of the light beam to and from one or more points within the scene, wherein the device comprises;

a lens element assembly configured to dynamically adjust a divergence of the light beam, such that a spot size of the light beam is adjusted.

2. The apparatus of claim 1, wherein:

the lens element assembly comprises a plurality of lens elements; and

to dynamically adjust a divergence of the light beam, at least one of the lens elements is configured to be translated, in a direction parallel to a direction of the light beam, relative to at least one other of the lens elements.

3. The apparatus of claim 2, wherein the plurality of lens elements comprises:

at least one lens element configured to be translated, in a direction parallel to a direction of the light beam, to dynamically adjust a diameter of the light beam along at least one axis of the light beam, relative to a diameter of the light beam along at least one other axis of the beam.

4. The apparatus of claim 3, wherein the plurality of lens elements further comprises:

at least one lens element configured to be translated, in a direction parallel to a direction of the light beam, to dynamically adjust a diameter of the light beam along the at least one other axis of the light beam, relative to a diameter of the light beam along at least one axis of the beam.

5. The apparatus of claim 1, comprising:

a scanner configured to scan the light beam, received from the lens element assembly, over a selected field of view of the scan range at one or more scan rates; and

a controller device configured to control at least the lens element assembly to dynamically adjust the divergence of the light beam as the light beam is scanned over at least a portion of the selected field of view;

wherein, to dynamically adjust the divergence of the light beam, such that the spot size of the light beam is adjusted, as the light beam is scanned over at least a portion of the selected field of view, the controller device is configured to control a position of at least a portion of the lens element assembly via at least one of;

an open loop control process;

or

a closed loop control process.

6. The apparatus of claim 1, wherein the lens element assembly comprises:

an actuated optical element configured to condition the light beam, such that the spot size of the light beam is adjusted.

7. The apparatus of claim 6, wherein the actuated optical element comprises an actuated beam expander lens assembly.

8. The apparatus of claim 1, wherein:

the light beam scanning device comprises a detector which is configured to receive the light reflected from at least a point within the field of view; and

to generate the image map of at least a portion of the scene, the light beam scanning device is configured to determine at least a depth, azimuth, and elevation of the portion of the scene, relative to at least a portion of the light beam scanning device, based at least in part upon the time of flight of the light beam to and from the point, and an orientation of the scanner.

9. The apparatus of claim 1, wherein:

the lens element assembly is configured to dynamically adjust a divergence of the light beam, such that a spot size of the light beam is adjusted to a particular beam spot size, based at least in part upon at least one of;

a selected beam spot size, of a set of predetermined beam spot sizes, or

a particular beam spot size specified by a received beam spot size command.

10. The apparatus of claim 1, wherein the light beam scanning device comprises a light detection and ranging (LIDAR) device.

11. A method, comprising:

dynamically adjusting a divergence of a light beam scanned, by a scanner, over a scene that is within a field of view of a scan range, such that a spot size of a beam spot of the light beam is dynamically adjusted, the dynamically adjusting comprising;

adjustably positioning at least one lens element, included in a lens element assembly located in the beam pathway, relative to an emitter of the light beam, such that the adjustably positioned lens element adjusts the divergence of the emitted light beam.

12. The method of claim 11, wherein adjustably positioning at least one lens element included in a lens element assembly comprises:

translating the at least one lens element in a direction parallel to a direction of the light beam and relative to at least one other lens element in the lens element assembly directing the beam of light to be scanned, by the scanner, over a first field of view at a first scan rate and at a first divergence; and

based at least in part upon a time of flight of the light beam to and from a particular portion of the scene within the first field of view, directing the beam of light to be scanned, by the scanner, over a second field of view at a second scan rate and at a second divergence, wherein the second field of view encompasses a limited region of the first field of view which includes the particular portion of the scene.

13. The method of claim 12, wherein directing the beam of light to be scanned, by the scanner, over a second field of view at a second scan rate and at a second divergence comprises:

selecting the second scan rate and the second divergence based at least in part upon the time of flight of the light beam to and from the particular portion of the scene within the first field of view.

14. The method of claim 12, wherein dynamically adjusting the divergence of the light beam comprises adjusting a divergence of at least one axis of the light beam, relative to a divergence of at least one other axis of the light beam.

15. The method of claim 14, wherein adjusting the divergence of the light beam comprises adjusting the divergence of the at least one axis of the light beam to equal the divergence of the at least one other axis of the light beam.

16. A method, comprising:

configuring a light beam scanning device to scan a light beam having a dynamically-adjustable divergence, within a scan range, over a scene that is within a field of view of the scan range and generate a map of at least a portion of the scene, based at least in part upon a time of flight of the light beam to and from one or more points within the scene, wherein the configuring comprises;

coupling a lens element assembly to at least a portion of the light-beam scanning device, wherein the lens element assembly is configured to adjust the divergence of the light beam.

17. The method of claim 16, wherein providing the lens element assembly in a light-beam scanning device comprises:

coupling the lens element assembly to a location along a pathway of the light beam between a transmitter configured to emit the light beam and a scanner configured to scan the light beam over the field of view of the scan range.

18. The method of claim 16, wherein:

the lens element assembly comprises a plurality of lens elements, wherein at least one of the lens elements is configured to be adjusted along a directional axis which is parallel to a pathway of the light beam and relative to at least one other of the lens elements to adjust the divergence of the light beam.

19. The method of claim 18, wherein the configuring comprises:

coupling the lens element assembly to a controller device configured to adjust the at least one of the lens elements based at least in part upon a time of flight of the light beam to and from one or more points within the scene.

20. The method of claim 16, wherein the configuring comprises:

coupling a detector to the light beam scanning device, wherein the detector is configured to receive the light reflected from at least a point within the field of view and generate an output indicating at least the time of flight of the light beam to and from the point, such that the light beam device is configured to;

determine at least a depth, azimuth, and elevation of the one or more points within the, relative to at least a portion of the light beam scanning device based at least in part upon the output generated by the detector and an orientation of the scanner; and

adjust the divergence of the light beam based at least in part upon the depth, azimuth, and elevation of the one or more points within the scene.