Imaging sensor having multiple fields of view and utilizing all-reflective optics

• US 5,831,762 A
• Filed: 06/21/1996
• Issued: 11/03/1998
• Est. Priority Date: 06/21/1996
• Status: Expired due to Term

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Cook, Lacy G., Baker, George F.
• Primary Examiner(s): Nguyen, Thong
• Assistant Examiner(s): Robinson, Mark A.
• Application Number:
  US08/667,577
• Time in Patent Office: 865 Days
• Field of Search: 359/351, 359/353, 359/365, 359/419, 359/420, 359/421, 359/366, 359/858, 359/859, 359/399, 359/400, 359/402, 359/407, 359/422, 359/432, 359/726, 359/727, 359/728, 359/729, 359/730, 359/731, 359/732, 250/353
• US Class Current: 359/353
• CPC Class Codes: G02B 17/02 Catoptric systems, e.g. image erecting and reversing system
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: G02B 26/125 Details of the optical system between the polygonal mirror and the image plane G02B26/123, G02B26/127 take precedence; F-Theta lenses G02B13/0005

Abstract

An imaging sensor has multiple fields of view of the same scene that may be selected by the user for viewing through mechanical movements. The imaging and selection are accomplished entirely with reflective optical components (mirrors) and without the use of any refractive optical components (lenses). A movable field-shifting mirror selects between a direct view and a modified-of-view image of the scene. The modified-view image is accomplished using a multi-mirror afocal telescope. Additional field-shifting mirrors may be used to select other fields of view and reference sources, as desired, or between various detectors.

Claims

1. A multiple field of view imaging sensor having a detector, comprising:

first means for imaging a scene onto the detector with a first field of view, the first means comprising a first optical path having at least one reflective component but no refractive component therein;

second means for imaging the scene onto the detector with a second field of view;

the second means comprising a second optical path having at least one reflective component but no refractive component therein; and

means including one or more flat moveable reflective components for selecting between first means and the second means by alternately routing light from the scene;

to either the first first means or the second means first to the second means.

2. The imaging sensor of claim 1, further including

third means for imaging the scene onto the detector with a third field of view:

the third means comprising a third optical path having at least one reflective component but no refractive component therein, and wherein the means for selecting is operable to select between the first means, the second means, and the third means by alternately routing light from the scene to either the first means, the second means or the third means.

3. The imaging sensor of claim 1, wherein the imaging sensor further includes

a reference source;

and

fourth means for imaging the reference source onto the detector;

the fourth means comprising a fourth optical path having at least one reflective component but no refractive component therein,

and wherein the means for selecting is operable to select between the first means, the second means, and the fourth means by alternately routing the optical path to either the first means, the second means or the fourth means.

4. The imaging sensor of claim 1, wherein the detector is an infrared detector, and wherein the imaging sensor further includes

a thermal reference source;

and

fourth means for imaging the thermal reference source onto the detector;

the fourth means comprising a fourth optical path having at least one reflective component but no refractive component therein and wherein the means for selecting is operable to select between the first means, the second means, and the fourth means.

5. The imaging sensor of claim 1, further including

a second detector, and

means for selecting between the first detector and the second detector for receiving an output of the means for selecting.

6. A multiple field of view imaging sensor, comprising:

a detector;

a detector optical path having an input image and an output image that is imaged onto the detector, the detector optical path having at least one reflective component but no refractive component therein;

a field-modifying optical path having an input image of the scene and an output image of the scene with a modified field of view, the field-modifying optical path including a telescope with at least one mirror but no retractive component therein; and

a field-shifting flat mirror movable between a first position and a second position, the mirror having an input in the first position of a scene with a first field of view and an input in the second position of the scene through the field-modifying optical path with the modified field of view, the field-shifting mirror having as an output in both the first position and the second position the input image to the detector optical path.

7. The imaging sensor of claim 6, wherein the detector optical path comprises

an image motion compensation mirror, and

at least one mirror.

8. The imaging sensor of claim 6, further including

a motor drive connected to the field-shifting mirror to controllably move the field-shifting mirror between the first position and the second position.

9. The imaging sensor of claim 6, wherein the field-modifying optical path comprises

a multi-mirror afocal telescope.

10. The imaging sensor of claim 6, wherein the imaging sensor further includes

a reference source;

and

means for imaging the reference source onto the detector, the means for imaging comprising an optical path having at least one reflective component but no refractive component therein.

11. The imaging sensor of claim 10, wherein the detector is an infrared detector and the reference source is a thermal reference source.

12. A multiple field of view imaging sensor, comprising:

a detector;

a detector optical path having an input image and an output image that is imaged onto the detector, the detector optical path having at least one mirror but no refractive component therein, comprising

an image motion compensation mirror that receives the input image,

a fixed fold mirror that receives as an input the output of the image motion compensation mirror, and

an imager optics having at least one reflective mirror, the output of the image optics being the output image;

a field-shifting mirror movable between a first position and a second position, the mirror having an input in the first position of a scene and an input in the second position, the mirror having as an output in both the first position and the second position the input image to the detector optical path; and

a field-modifying optical path having an input image of the scene and an output image of the scene with a modified field of view, the field-modifying optical path comprising

a multi-mirror afocal telescope with at least one mirror but no refractive component therein, and

a fixed mirror that receives as an input the output of the multi-mirror afocal telescope;

an optical input selected from the group consisting of an output of a reference source and an output of a second field-modifying optical path; and

a second field-shifting mirror movable between a first position and a second position, the mirror having an input in the first position of the scene with a modified field of view from the field-modifying optical path and an input in the second position of the optical input, the mirror having as an output in both the first position and the second position the input in the second position of the field-shifting mirror.

13. The imaging sensor of claim 12, wherein the reference source comprises

a thermal reference source.

14. The imaging sensor of claim 12, wherein the second field-modifying optical path comprises:

a second multi-mirror afocal telescope with at least one mirror but no refractive component therein, and

a second fixed mirror that receives as an input the output of the second multi-mirror afocal telescope.

15. The imaging sensor of claim 12, wherein the detector is an infrared detector.

16. The imaging sensor of claim 12, further including

a motor drive connected to the field-shifting mirror to controllably move the field-shifting mirror between the first position and the second position.