Ladar transmitter with ellipsoidal reimager

• US 10,642,029 B2
• Filed: 08/01/2018
• Issued: 05/05/2020
• Est. Priority Date: 02/18/2016
• Status: Active Grant

• Current Assignee: AEye, Inc.
• Original Assignee: AEye, Inc.
• Inventors: Dussan, Luis Carlos, Demmer, David R., Stockton, John, Steinhardt, Allan, Cook, David
• Primary Examiner(s): Carruth, Jennifer D.
• Application Number:
  US16/051,707
• Publication Number:
  US 20180341103A1
• Time in Patent Office: 643 Days
• Field of Search: None
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 27/126 The splitting element being a prism or prismatic array, including systems based on total internal reflection
• CPC Class Codes: G02B 27/14 operating by reflection only
• CPC Class Codes: G02B 27/141 using dichroic mirrors

Abstract

Disclosed herein is a compact beam scanner assembly that includes an ellipsoidal reimaging mirror.

Claims

1. A scanner apparatus comprising:

a first scanable mirror;

a second scanable mirror;

a lens that is positioned optically upstream from the first scanable mirror; and

an ellipsoidal mirror that is positioned optically between the first scanable mirror and the second scanable mirror, and wherein the ellipsoidal mirror is positioned as an offset ellipsoidal reimager.

2. The apparatus of claim 1 further comprising:

a light source positioned optically upstream from the lens, wherein the light source is configured to transmit light through the lens onto the first scanable mirror, whereupon the first scanable mirror reflects the light toward the offset ellipsoidal mirror, and whereupon the offset ellipsoidal mirror reflects the light toward the second scanable mirror.

3. The apparatus of claim 2 arranged as a ladar transmitter, the apparatus further comprising:

a beam scanner controller configured to (1) scan the first scanable mirror along a first axis, and (2) scan the second scanable mirror along a second axis to define a scan pattern within a scan area; and

a processor in cooperation with the light source and the beam scanner controller, the processor configured to intelligently select, via compressive sensing, a subset of range points for targeting with light from the light source via the first scanable mirror, the offset ellipsoidal mirror, and the second scanable mirror.

4. The apparatus of claim 3 wherein the first and second scanable mirrors are positioned in a side-by-side arrangement.

5. The apparatus of claim 4 wherein the first scanable mirror, the second scanable mirror, and the offset ellipsoidal mirror are positioned such that, with respect to an ellipsoid, (1) the first scanable mirror has a central region that is positioned at a first focus of the ellipsoid, (2) the second scanable mirror has a central region that is positioned at a second focus of the ellipsoid, and (3) the offset ellipsoidal mirror lies along the ellipsoid at a position that is optically between the first scanable mirror and the second scanable mirror.

6. The apparatus of claim 5 wherein the ellipsoid has a major axis and an axis of symmetry along the major axis, and wherein the offset ellipsoidal mirror position is off the axis of symmetry.

7. The apparatus of claim 1 wherein the first scanable mirror and the second scanable mirror comprise MEMS mirrors.

8. The apparatus of claim 7 wherein the first and second scanable MEMS mirrors are positioned in a side-by-side arrangement.

9. The apparatus of claim 1 wherein the first scanable mirror and the second scanable mirror are of equal size.

10. The apparatus of claim 1 further comprising:

a beam scanner controller configured to (1) scan the first scanable mirror along a first axis, and (2) scan the second scanable mirror along a second axis to define a scan pattern within a scan area such that at least one of the first scanable mirror and the second scanable mirror scans at a sinusoidal frequency.

11. The apparatus of claim 1 wherein the first and second scanable mirrors are positioned in a side-by-side arrangement.

12. A light steering method comprising:

transmitting light toward a lens;

the lens passing the transmitted light to a first scanning mirror;

the first scanning mirror reflecting the transmitted light toward an ellipsoidal mirror, wherein the ellipsoidal mirror is positioned as an offset ellipsoidal reimager;

the offset ellipsoidal mirror reflecting the transmitted light toward a second scanning mirror; and

the second scanning mirror reflecting the transmitted light.

13. The method of claim 12 further comprising a processor intelligently selecting, via compressive sensing, a subset of range points for targeting by a ladar transmitter via the first and second scanning mirrors.

14. The method of claim 13 wherein the first and second scanning mirrors are positioned in a side-by-side arrangement.

15. The method of claim 14 wherein the first scanning mirror, the second scanning mirror, and the offset ellipsoidal mirror are positioned such that, with respect to an ellipsoid, (1) the first scanning mirror has a central region that is positioned at a first focus of the ellipsoid, (2) the second scanning mirror has a central region that is positioned at a second focus of the ellipsoid, and (3) the offset ellipsoidal mirror lies along the ellipsoid at a position that is optically between the first scanning mirror and the second scanning mirror.

16. The method of claim 15 wherein the ellipsoid has a major axis and an axis of symmetry along the major axis, and wherein the offset ellipsoidal mirror position is off the axis of symmetry.

17. The method of claim 12 wherein the first scanning mirror and the second scanning mirror comprise MEMS mirrors.

18. The method of claim 17 wherein the first and second scanable MEMS mirrors are positioned in a side-by-side arrangement.

19. The method of claim 12 wherein the first scanning mirror and the second scanning mirror are of equal size.

20. The method of claim 12 further comprising:

scanning the first scanning mirror along a first axis and scanning the second scanning mirror along a second axis to define a scan pattern within a scan area such that at least one of the first scanning mirror and the second scanning mirror scans at a sinusoidal frequency.

21. The method of any of claim 12 wherein the first and second scanning mirrors are positioned in a side-by-side arrangement.