Optical system

• US 7,297,934 B2
• Filed: 06/13/2005
• Issued: 11/20/2007
• Est. Priority Date: 12/12/2003
• Status: Active Grant

• Current Assignee: Arete Associates
• Original Assignee: Arete Associates
• Inventors: Kane, David M.
• Primary Examiner(s): Epps; Georgia
• Assistant Examiner(s): Lee; Patrick J.
• Application Number:
  US11/151,594
• Publication Number:
  US 20060006337A1
• Time in Patent Office: 890 Days
• Field of Search: 250/206, 250/216, 250/230, 359197-203, 359212-217, 356 401- 409, 35613101- 13, 3561411-141, 398118-131, 398140-172, 398202-214
• US Class Current: 250/230
• CPC Class Codes: G01J 3/021 using plane or convex mirrors, parallel phase plates, or particular reflectors
• CPC Class Codes: G01J 3/0256 Compact construction
• CPC Class Codes: G01J 3/0289 Field-of-view determination; Aiming or pointing of a spectrometer; Adjusting alignment; Encoding angular position; Size of measurement area; Position tracking
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 17/89 for mapping or imaging
• 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 26/105 with one or more pivoting mirrors or galvano-mirrors G02B26/101 takes precedence

Abstract

In preferred forms of the invention an array of MEMS mirrors or small mirrors inside an optical system operates closed-loop. These mirrors direct external source light, or internally generated light, onto an object—and detect light reflected from it onto a detector that senses the source. Local sensors measure mirror angles relative to the system. Sensor and detector outputs yield source location relative to the system. One preferred mode drives the MEMS mirrors, and field of view seen by the detector, in a raster, collecting a 2-D or 3-D image of the scanned region. Energy reaching the detector can be utilized to analyze object characteristics, or with an optional active distance-detecting module create 2- or 3-D images, based on the object'"'"'s reflection of light back to the system. In some applications, a response can be generated. The invention can detect sources and locations for various applications.

Claims

1. An optical system for dynamically determining radiation characteristics, including associated angular direction throughout a specified range of angular directions, of an external article in a volume outside the system;

said optical system comprising;

an optical detector;

an entrance aperture;

an afocal element, associated with the aperture, for enlarging the field of regard of such external article and such volume as seen by the detector; and

disposed along an optical path between the detector and the entrance aperture, at least one mirror, rotatable about plural axes, for causing the detector to address varying portions of such volume outside the optical system;

each mirror of the at least one mirror having dimensions in a range from thirty microns to five millimeters;

wherein, due to said enlarging of the field of regard together with rotation of the at least one mirror, such external article is visible to the detector throughout the specified range, substantially without changing magnitude of said enlarging.

2. The optical system of claim 1, wherein:

each mirror of the at least one mirror is a microelectromechanical mirror.

3. The optical system of claim 1, wherein:

the afocal element is an afocal lens assembly disposed at the aperture, and amplifies the varying introduced by the at least one mirror.

4. The optical system of claim 3:

wherein the afocal lens assembly does not focus such external article onto any solid element of the optical system; and

further comprising a focusing lens, associated with the detector, for;

intercepting a radiation beam that has passed through the afocal lens assembly, and that also has been reflected by the at least one mirror, and

focusing rays, in said radiation beam, from such external article onto the detector.

5. The optical system of claim 1, wherein:

the afocal enlarging element is disposed generally at the aperture.

6. The optical system of claim 1, wherein:

the afocal enlarging element defines the aperture.

7. The optical system of claim 1:

further comprising an imaging module; and

wherein the afocal enlarging element and the at least one mirror are shared by both;

the imaging module, and

the detector with its focusing lens.

8. The optical system of claim 1:

further comprising a spectral-analysis module; and

wherein the afocal enlarging element and the at least one mirror are shared by both;

the spectral-analysis module, and

the detector with its focusing lens.

9. The optical system of claim 1:

further comprising an auxiliary optical system that includes at least one of;

a ranging laser for projecting a ranging beam to such article, and

a ranging-laser receiving module, distinct from the aforesaid detector with its focusing lens, for receiving and analyzing the ranging beam after reflection from such article; and

wherein the afocal enlarging element and the at least one mirror are shared by both;

one or both of the ranging laser and receiving module, and

the detector with its focusing lens.

10. The optical system of claim 1:

further comprising an auxiliary optical system that includes at least one of;

a communication-beam transmission module for transmitting a first modulated communication beam toward such article, and

a communication-beam reception module, distinct from the aforesaid detector with its focusing lens, for receiving and interpreting a second modulated communication beam received from such article or from a region of such volume that includes such article; and

wherein the afocal enlarging element and the at least one mirror are shared by both;

one or both of the transmission and reception modules, and

the detector with its focusing lens.

11. The optical system of claim 1:

further comprising an auxiliary optical system that includes at least one of;

a communication-beam transmission module for transmitting a first modulated communication beam toward such article, and

a communication-beam reception module for receiving and interpreting a second modulated communication beam received from such article or from a region of such volume that includes such article; and

wherein the afocal enlarging element and the at least one mirror are shared by one or both of the transmission and reception modules.

12. The optical system of claim 1:

further comprising a powerful laser for projecting a beam to impair function or structural integrity of such article; and

wherein the afocal enlarging element and the at least one mirror are shared by both;

the powerful laser, and

the detector with its focusing lens.

13. The optical system of claim 1:

further comprising a laser for dazzling or confusing either a human operator or optical apparatus associated with such article, or both; and

wherein the afocal enlarging element and the at least one mirror are shared by both;

the dazzling laser, and

the detector with its focusing lens.

14. The optical system of claim 1:

wherein the detector reports relative location of incident radiation on a sensitive surface of the detector; and

further comprising means for automatically responding to the detector by actively servocontrolling the at least one mirror to substantially center an image of a detected source on the detector.

15. The optical system of claim 14, wherein the external article comprises a radiation source of a particular type, said characteristics comprise existence and presence of the source, and the optical system is for detecting the source and determining its angular location, and:

said optical detector is a detector for such radiation from such source of such particular type; and

further comprising means for automatically responding to the detector by actively servocontrolling the at least one mirror to substantially center an image of a detected source on the detector.

16. The optical system of claim 15, further comprising:

means for reading and interpreting angular position from mirror position feedback signals while the image is substantially centered on the detector.

17. The optical system of claim 16, wherein:

the responding means comprise means for continuing to servocontrol the at least one mirror to track the already-detected source substantially at the detector center.

18. The optical system of claim 17, wherein:

the at least one mirror comprises plural mirrors; and

the continuing means comprise means for using one or more mirrors to track the already-detected source, and one or more other mirrors to instead simultaneously perform another function.

19. The optical system of claim 18, wherein:

the other function comprises searching for another source, previously not yet detected.

20. The optical system of claim 18, wherein:

the other function comprises operating the auxiliary optical system with respect to said already-detected source or another article or scene.

21. The optical system of claim 17, further comprising:

operating a beam-splitter to enable use of an auxiliary optical system, with respect to said alreadydetected source or another article or scene, simultaneously with said continuing tracking of the already-detected source.

22. The optical system of claim 1, wherein:

the detector is a position-sensing detector (PSD).

23. The optical system of claim 1, wherein:

the detector is a quad cell.

24. The optical system of claim 1, further comprising:

means for substituting a detector array for the detector, to image the already-detected source or associated articles, or both.

25. The optical system of claim 1, further comprising:

means for directing a response toward the detected article or an article associated therewith, or both.

26. The optical system of claim 25, wherein:

the response-directing means comprise means for emitting a beam of radiation that uses said entrance aperture as an exit aperture and is reflected from said at least one mirror;

wherein the response-directing means share, with such radiation from such source, both;

said entrance aperture, and

said at least one mirror.

27. An optical system for dynamically determining radiation characteristics, including associated angular direction, of an external article in a volume outside the system;

said optical system comprising;

an optical detector;

an entrance aperture;

an afocal optically powered element, associated with the aperture, for enlarging the field of regard of such external article and such volume as seen by the detector; and

wherein the afocal element does not focus such external article onto any solid element of the optical system;

disposed along an optical path between the detector and the entrance aperture, at least one mirror, rotatable about plural axes, for causing the detector to address varying portions of such volume outside the optical system and with the enlarged field of regard produced by the afocal element;

a focusing lens, associated with the detector, for;

intercepting a radiation beam that has passed through the afocal element, and that also has been reflected by the at least one mirror, and

focusing rays, in said radiation beam, from such external article onto the detector;

wherein the afocal element and mirror cooperate with the focusing lens and detector, to image such article onto the detector.

28. The optical system of claim 27, wherein:

the afocal enlarging element is disposed generally at the aperture.

29. The optical system of claim 27, wherein:

the afocal enlarging element defines the aperture.

30. The optical system of claim 27:

further comprising an imaging module; and

wherein the afocal enlarging element and the at least one mirror are shared by both;

the imaging module, and

the detector with its focusing lens.

31. The optical system of claim 30, wherein:

each mirror of the at least one mirror has dimensions in a range from thirty microns to five millimeters.

32. The optical system of claim 27:

further comprising a spectral-analysis module; and

wherein the afocal enlarging element and the at least one mirror are shared by both;

the spectral-analysis module, and

the detector with its focusing lens.

33. The optical system of claim 32, wherein:

each mirror of the at least one mirror has dimensions in a range from thirty microns to five millimeters.

34. The optical system of claim 27:

further comprising an auxiliary optical system that includes at least one of;

a ranging laser for projecting a ranging beam to such article, and

a ranging-laser receiving module, distinct from the aforesaid detector with its focusing lens, for receiving and analyzing the ranging beam after reflection from such article; and

wherein the afocal enlarging element and the at least one mirror are shared by both;

one or both of the ranging laser and receiving module, and

the detector with its focusing lens.

35. The optical system of claim 34, wherein:

each mirror of the at least one mirror has dimensions in a range from thirty microns to five millimeters.

36. The optical system of claim 27:

further comprising an auxiliary optical system that includes at least one of;

a communication-beam transmission module for transmitting a first modulated communication beam toward such article, and

a communication-beam reception module, distinct from the aforesaid detector with its focusing lens, for receiving and interpreting a second modulated communication beam received from Buch article or from a region of such volume that includes such article; and

wherein the afocal enlarging element and the at least one mirror are shared by both;

one or both of the transmission and reception modules, and

the detector with its focusing lens.

37. The optical system of claim 36, wherein:

each mirror of the at least one mirror has dimensions in a range from thirty microns to five millimeters.

38. The optical system of claim 27:

further comprising a powerful laser for projecting a beam to impair function or structural integrity of such article; and

wherein the afocal enlarging element and the at least one mirror are shared by both;

the powerful laser, and

the detector with its focusing lens.

39. The optical system of claim 38, wherein:

each mirror of the at least one mirror has dimensions in a range from thirty microns to five millimeters.

40. The optical system of claim 27:

further comprising a laser for dazzling or confusing either a human operator or optical apparatus associated with such article, or both; and

wherein the afocal enlarging element and the at least one mirror are shared by both;

the dazzling laser, and

the detector with its focusing lens.

41. The optical system of claim 40, wherein:

each mirror of the at least one mirror has dimensions in a range from thirty microns to five millimeters.

42. The optical system of claim 27:

wherein the detector reports relative location of incident radiation on a sensitive surface of the detector; and

further comprising means for automatically responding to the detector by actively servocontrolling the at least one mirror to substantially center an image of a detected source on the detector.

43. An optical system for dynamically determining radiation characteristiCs, including associated angular direction, of an external article in a volume outside the syBtem;

said optical system comprising;

an optical detector;

an entrance aperture;

an afocal optically powered element, disposed generally at the aperture, for reducing the field of regard of such external article and such volume as seen by the detector; and

wherein the afocal reducing element does not focus such external article onto any solid element of the optical system;

disposed along an optical path between the detector and the entrance aperture, at least one mirror, rotatable about plural axes, for causing the detector to address varying portions of such volume outside the optical system and with the reduced field of regard produced by the afocal reducing element;

a focusing lens, associated with the detector, for;

intercepting a radiation beam that has passed through the afocal reducing element, and that also has been reflected flected by the at least one mirror, and

focusing rays, in said radiation beam, from such external article onto the detector;

wherein the afocal reducing element and mirror cooperate with the focusing lens and detector, to image such article onto the detector.

44. The optical system of claim 43:

further comprising an auxiliary optical system that includes at least one of;

a communication-beam transmission module for transmitting a first modulated communication beam toward such article, and

a communication-beam reception module, distinct from the aforesaid detector with its focusing lens, for receiving and interpreting a second modulated communication beam received from such article or from a region of such volume that includes such article; and

wherein the afocal reducing element and the at least one mirror are shared by both;

the detector with its focusing lens, and

one or both of the transmission and reception modules.

45. The optical system of claim 43, wherein:

each mirror of the at least one mirror has dimensions in a range from thirty microns to five millimeters.

46. The optical system of claim 43:

wherein the detector reports relative location of incident radiation on a sensitive surface of the detector; and

further comprising means for automatically responding to the detector by actively servocontrolling the at least one mirror to substantially center an image of a detected source on the detector.

47. The optical system of claim 43:

further comprising an auxiliary optical system that includes an imaging reception module, distinct from the aforesaid detector with its focusing lens, for receiving and interpreting an image beam received from such article or from a region of such volume that includes such article; and

wherein the afocal reducing element and the at least one mirror are shared by both;

the detector with its focusing lens, and

the imaging reception module.