Multiple field-of-view (FOV) optical sensor using a micro-electro-mechanical system (MEMS) micro- mirror array (MMA)

Patent metadata

Field	Value
Publication number	US-12130384-B2
Application number	US-202117217929-A
Country	US
Kind code	B2
Filing date	Mar 30, 2021
Priority date	Mar 30, 2021
Publication date	Oct 29, 2024
Grant date	Oct 29, 2024

Abstract

A multiple FOV optical sensor includes a primary mirror having first and second rings of differing curvature to collect light from an object within different FOV. A secondary mirror includes a MEMS MMA in which the mirrors tip and tilt in 2 DOF or add piston in 3 DOF to (I) reflect light from the first ring within the first FOV that is focused at an imaging plane coincident with an imaging detector to form a focused image of the object at the imaging detector or (II) reflect light from the second ring within the second FOV onto the imaging detector (either focused to form a focused image or defocused to form a blurred spot). The MEMS MMA may be configured to alternate between (I) and (II) or to perform both (I) and (II) at the same time with the different FOV either overlapped or spatially separated on the detector. The sensor may be configured as an all-passive sensor, a dual-mode sensor or a hybrid of the two.

First claim

We claim:

1. A multiple field-of-view (FOV) optical sensor, comprising:
an imaging detector configured to sense light and readout an image;
a primary mirror including
a first ring having a first curvature configured to collect light from an object within a first FOV; and
a second ring having a second curvature configured to collect light from the object within a second FOV different than said first FOV;

a secondary mirror comprising a Micro-Electro-Mechanical System (MEMS) Micro-Mirror Array (MMA) including a plurality of mirrors, said MEMS MMA responsive to command signals to tip and tilt the mirrors in two degrees-of-freedom (DOF) to (I) reflect light from the first ring within the first FOV that is focused to an imaging plane coincident with the imaging detector to form a focused image of the object at the imaging detector and (II) reflect light from the second ring within the second FOV of the object onto the imaging detector.

2. The multiple FOV optical sensor of claim 1 , wherein without correction by the MEMS MMA in (II), light reflected from the second ring within the second FOV is focused to an imaging plane offset from the imaging detector to form a blurred spot of the object at the imaging detector.

3. The multiple FOV optical sensor of claim 2 , wherein said MEMS MMA is responsive to additional command signals to tip and tilt the mirrors to adjust the offset of the imaging plane to control the blurred spot.

4. The multiple FOV optical sensor of claim 2 , wherein passive light from the object is reflected from the first ring to form the focused image at the imaging detector and active light reflected from the object is reflected from the second ring to form the blurred spot at the imaging detector.

5. The multiple FOV optical sensor of claim 2 , wherein said MEMS MMA is responsive to additional command signals to tip and tilt the mirrors to adjust the imaging plane to be coincident with the imaging detector to form a focused image of the object at the imaging detector for the second FOV.

6. The multiple FOV optical sensor of claim 5 , wherein the mirrors tip, tilt and piston in 3 DOF, wherein said MEMS MMA is responsive to additional command signals to piston the mirrors to adjust the optical path length along each ray at the center of each mirror to preserve the phase coherence at the imaging plane coincident with the imaging detector.

7. The multiple FOV optical sensor of claim 1 , wherein in (II) said MEMS MMA is responsive to additional command signals to tip and tilt the mirrors to adjust the imaging plane to be coincident with the imaging detector to form a focused image of the object at the imaging detector for the second FOV, wherein passive light from the object is reflected from the first and second rings to form the focused images of the object at the imaging detector in the different first and second FOV.

8. The multiple FOV optical sensor of claim 1 , wherein the MEMS MMA is responsive to command signals to alternate between reflecting light from the first ring to the imaging detector and reflecting light from the second ring away from the imaging detector as stray light and reflecting light from the second ring to the imaging detector and reflecting light from the first ring away from the imaging detector as stray light.

9. The multiple FOV optical sensor of claim 8 , wherein passive light in a first spectral band from the object is reflected from the first ring to form the focused image at the imaging detector in the first FOV and active light in a second spectral band reflected from the object is reflected from the second ring to form a blurred spot at the imaging detector within the second FOV.

10. The multiple FOV optical sensor of claim 9 , wherein the imaging detector is configured to separately sense and readout images in the first and second spectral bands, respectively.

11. The multiple FOV optical sensor of claim 8 , wherein passive light from the object is reflected from the first ring to form the focused image at the imaging detector in the first FOV, wherein said MEMS MMA is responsive to additional command signals to tip and tilt the mirrors to adjust the imaging plane to be coincident with the imaging detector to form a focused image of the object at the imaging detector for passive light in the second FOV.

12. The multiple FOV optical sensor of claim 1 , wherein the MEMS MMA is responsive to command signals to simultaneously partition the mirrors into two segments such that light from both the first and second FOV overlap spatially at the imaging detector.

13. The multiple FOV optical sensor of claim 12 , wherein passive light from the object is reflected from the first ring to form the focused image at the imaging detector and active light reflected from the object is reflected from the second ring to form a blurred spot at the imaging detector, wherein the imaging detector is configured to separately sense and readout images in the first and second spectral bands, respectively.

14. The multiple FOV optical sensor of claim 1 , wherein the MEMS MMA is responsive to command signals to simultaneously partition the mirrors into two segments to reflect the light from the first and second rings to different non-overlapping portions of the imaging detector such that each read out image includes both the first and second FOV in the different non-overlapping portions of the image, respectively.

15. The multiple FOV optical sensor of claim 14 , wherein passive light in a first spectral band from the object is reflected from the first ring to form the focused image at the imaging detector in the first FOV and active light in a second spectral band reflected from the object is reflected from the second ring to form a blurred spot at the imaging detector within the second FOV, wherein the imaging detector is configured to separately sense and readout images in the first and second spectral bands, respectively, to form the image including the focused image of the object in the first FOV in one portion of the image and the blurred spot of the object in the second FOV in the other portion of the image.

16. The multiple FOV optical sensor of claim 1 , wherein the plurality of mirrors of the MEMS MMA approximate a base curvature to provide additional optical power to direct light reflected from the first or second rings to the imaging detector.

17. A multiple field-of-view (FOV) optical sensor, comprising:
an imaging detector configured to sense light and readout an image;
a primary mirror including
a first ring having a first curvature configured to collect passive light from an object within a first FOV; and
a second ring having a second curvature configured to collect active light reflected from the object within a second FOV different than said first FOV;

a secondary mirror comprising a Micro-Electro-Mechanical System (MEMS) Micro-Mirror Array (MMA) including a plurality of mirrors, said MEMS MMA responsive to command signals to tip and tilt the mirrors in two degrees-of-freedom (DOF) to alternate between (I) reflect passive light from the first ring within the first FOV that is focused to an imaging plane coincident with the imaging detector to form a focused image of the object at the imaging detector while reflecting light from the second ring away from the imaging detector as stray light and (II) reflect light from the second ring within the second FOV to form a blurred spot of the object at the imaging detector while reflecting light from the second ring away from the imaging detector as stray light.

18. The multiple FOV optical s

Assignees

• Raytheon Co

Inventors

• Dutton Andrew W
• Uyeno Gerald P
• Keller Sean D
• Rogala Eric

Classifications

• G02B26/0833 Primary

  the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B26/0825 takes precedence; micromechanical devices in general B81B) · CPC title

• G01S17/89

  for mapping or imaging · CPC title

• G01S7/4817 Primary

  relating to scanning · CPC title

• G02B17/0808

  on-axis systems with at least one of the mirrors having a central aperture · CPC title

• G02B17/08

  Catadioptric systems {(used in non-imaging applications G02B19/00)} · CPC title