Dispersive microlens

• US 5,497,269 A
• Filed: 06/25/1992
• Issued: 03/05/1996
• Est. Priority Date: 06/25/1992
• Status: Expired due to Term

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Space Operations Company (Martin Marietta Corporation)
• Inventors: Gal, George
• Primary Examiner(s): Epps, Georgia Y.
• Assistant Examiner(s): PAPALAS, MICHAEL
• Application Number:
  US07/904,316
• Time in Patent Office: 1,349 Days
• Field of Search: 359/625, 359/626, 359/619, 359/741, 359/742, 359/743, 359/628, 359/615, 359/565, 359/566, 359/569, 359/570, 359/571, 356/328
• US Class Current: 359/615
• CPC Class Codes: G02B 27/1006 for splitting or combining different wavelengths G02B27/1086, G02B27/141 take precedence
• CPC Class Codes: G02B 27/123 The splitting element being a lens or a system of lenses, including arrays and surfaces with refractive power
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: G02B 3/08 with discontinuous faces, e.g. Fresnel lens diffractive Fresnel lenses G02B5/1876
• CPC Class Codes: G02B 5/1876 Diffractive Fresnel lenses; Zone plates; Kinoforms G02B5/1842, G02B5/1847 take precedence; optical systems having diffractive correction means G02B27/0037; Fresnel lenses operating by refraction G02B3/08
• CPC Class Codes: G02B 5/1885 Arranged as a periodic array
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device

Abstract

Dispersive microlens apparatus and methods are used in one mode for detecting multiple, different wavelengths from a bandwidth of wavelengths (existing within an image plane blur spot) and are used in another mode for combining a plurality of different, emitted wavelengths into a bandwave of wavelengths (at a blur spot in an image plane).

Claims

1. A unitary, dispersive microlens apparatus for use in dispersing a bandwidth of light into multiple selected wavelengths or wavebands of light at specified locations in an elongated blur spot so that detectors in the specified locations can detect the multiple wavelengths or wavebands, said microlens apparatus having height dimensions in the order of a few micrometers, said microlens comprising,

a microlens constructed to transmit and to concentrate a selected bandwidth of light existing in a blur spot at the microlens to a smaller blur spot in a detector plane spaced at a selected distance from the microlens, and

dispersion means for producing both a dispersion of the bandwidth of light as the light is transmitted and concentrated to the smaller blur spot and also an elongated shape of the smaller blur spot in which the wavelengths or wavebands are varied from one end of the elongated blur spot to the other so that more than one wavelength can be detected by detectors at specified locations within the elongated blur spot in the detector plane, said dispersive means comprising a grating formed integrally on the microlens and wherein the unitary construction of the grating integrally on the microlens enables one unitary, dispersive microlens apparatus to perform multiple, designed, refraction and dispersion functions while eliminating noise and reflection losses which could otherwise occur across an interface between a separated, non-unitary microlens and grating.

2. The invention defined in claim 1 wherein the dispersion means comprise a blazed grating formed integrally on the microlens.

3. A unitary, dispersive bidirectional microlens apparatus which can be used in a first mode, in which first mode light is transmitted through the microlens apparatus in a first direction, for detecting multiple different wavelengths from a bandwidth of the wavelengths existing within the microlens apparatus at an image plane blur spot and which can be used in a second mode, in which second mode light is transmitted through the microlens apparatus in a second direction opposite to said first direction, for combining a plurality of different, emitted wavelengths into a bandwidth of the wavelengths within the microlens apparatus, said dispersive microlens apparatus comprising,

a microlens constructed to be positioned in an image plane at an image plane blur spot and to transmit and to concentrate a selected bandwidth of light from the image plane blur spot into a smaller detector/emitter plane blur spot in a detector/emitter plane which is spaced from the image plane, and

dispersion means for producing, in relation to the bandwidth of light in the image plane blur spot, a dispersion of the bandwidth of light and an elongated detector/emitter plane blur spot in which the wavelengths are varied and dispersed to specified locations from one end to the other of the smaller, elongated blur spot so that, in said first mode, more than one wavelength and/or bands of wavelengths can be detected by detectors at the specified locations within the elongated blur spot when light is transmitted from the image plane to the detector plane and so that, in said second mode, a plurality of specified wavelengths of light can be emitted from a plurality of specified locations in the elongated blur spot and can be combined into a bandwidth of light in the image plane blur spot when light is transmitted from the emitter plane to the image plane, said dispersion means comprising a grating formed integrally on the microlens and wherein the unitary construction of the grating integrally on the microlens enables one unitary, dispersive microlens apparatus to perform multiple, designed, refraction and dispersion functions while eliminating noise and reflection losses which could otherwise occur across an interface between a separated, non-unitary microlens and grating.

4. The invention defined in claim 3 wherein the dispersion means comprise a blazed grating formed integrally on the microlens.

5. Apparatus for transmitting and concentrating optical information contained in optical blur spots in an image plane to small fractions of the areas of related pixels in a detector plane which is spaced from the image plane, said apparatus comprising,

microlens means comprising a plurality of individual microlenses, positioned at a plurality of image plane blur spot locations, for transmitting and concentrating the optical information in an image plane blur spot into a smaller detector plane blur spot in a related pixel in the detector plane, so that the area of the detector plane blur spot is decoupled from the area of the pixel, and for producing a contrast ratio, fill factor and optical gain of said optical information in the detector plane blur spot with respect to any existing, unwanted noise present at the detector plane,

at least certain ones of said individual microlenses including a grating formed integrally on the individual microlens for dispersing the optical information in at least certain ones of the image plane blur spots to create an elongation of a related detector plane blur spot and a dispersed distribution of the optical information to specific locations within that elongated blur spot which permits multiple, different signals to be detected by detectors at the specific locations within that elongated blur spot and wherein the unitary construction of the grating integrally on the microlens enables one unitary, dispersive microlens to perform multiple, designed, refraction and dispersion functions while eliminating noise and reflection losses which could otherwise occur across an interface between a separated, non-unitary microlens and grating.

6. The invention defined in claim 5 wherein the microlens means include an array of individual, dispersive microlenses and wherein the dispersion means comprise a blazed grating formed integrally and in a regular pattern on each individual, dispersive microlens.

7. The invention defined in claim 6 wherein the microlens means comprise circular shaped microlenses.

8. The invention defined in claim 6 wherein the microlens means comprise square shaped microlenses.

9. The invention defined in claim 6 wherein the microlens means comprise hexagonally shaped microlenses.

10. The invention defined in claim 6 wherein the microlens means comprise rhombic shaped microlenses.

11. The invention defined in claim 6 wherein the microlens means comprise non-Fresnel microlenses.

12. The invention defined in claim 6 wherein the microlens means comprise Fresnel microlenses.

13. The invention defined in claim 6 wherein the microlens means comprise microlenses which are non-Fresnel, non-binary microlens.

14. The invention defined in claim 6 wherein the microlens means comprise microlenses which are non-Fresnel binary microlenses.

15. The invention defined in claim 6 wherein the microlens means comprise microlenses which are non-Fresnel type lenses and which are analog microlenses.

16. The invention defined in claim 6 wherein the microlens means comprise microlenses which are Fresnel lenses and which are non-binary microlenses.

17. The invention defined in claim 6 wherein the microlens means comprise microlenses which are Fresnel lenses and which are binary microlenses.

18. The invention defined in claim 6 wherein the individual dispersive microlenses are arranged in rows in the array.

19. The invention defined in claim 5 including detector means for detecting multiple, different signals from the optical information in each elongated blur spot to thereby permit real time discrimination of the optical information for certain qualities, such as for example, the color and/or temperature, of the object or objects generating or reflecting the optical information.

20. The invention defined in claim 19 wherein the detector means include three detectors in each elongated blur spot for detecting high, medium and low color information.

21. The invention defined in claim 20 including electronic means for supplying the detected color information to a processor which uses the detected color information for color displays, such as color television, color recording, color facsimile, and color printing.

22. The invention defined in claim 19 wherein the detector means include multiple, individual detectors in each elongated blur spot for detecting multiple signals which can be summed in an acquisition mode to obtain an increased signal and which can be used in a discrimination mode to evaluate color contrast to determine object temperature and also to discriminate for temperature on the basis of the ratios of the detected energies.

23. The invention defined in claim 22 wherein the multiple, individual detectors provide signals which enable the use of a few spectral bands to suppress background and to enhance signal detectability.

24. The invention defined in claim 22 wherein two detectors looking at the same scene can be used to detect lack of registration between two objects.

25. The invention defined in claim 22 wherein the multiple, separate detectors can be selectively sized and positioned in the elongated blur spot pick up different, selected sets of information dependent on the sizes and positions of the detectors in the elongated blur spot.

26. The invention defined in claim 19 including analog circuit means for processing signals produced by the detector means.

27. The invention defined in claim 26 wherein the analog circuit means are used for combining the signals for enhanced signal-to-noise and/or for ratioing the signals as required.

28. The invention defined in claimed 27 wherein the analog circuit means for each detector means are placed next to the detector means on the otherwise unused portion of the area existing outside the respecitve detector/emitter plane blur spots.

29. Apparatus for transmitting and concentrating optical information contained in optical blur spots in an image plane to small fractions of the areas of related pixels in a detector plane which is spaced from the image plane, said apparatus comprising,

microlens means, positioned at a plurality of image plane blur spot locations, for transmitting and concentrating the optical information in an image plane blur spot into a smaller detector plane blur spot in a related pixel in the detector plane, so that the area of the detector plane blur spot is decoupled from the area of the pixel, and for producing a contrast ratio, fill factor and optical gain of said optical information in the detector plane blur spot with respect to any existing, unwanted noise present at the detector plane,

certain ones of said microlens means including dispersion means formed integrally on said microlens means for dispersing the optical information in at least certain ones of the image plane blur spots to create an elongation of a related detector plane blur spot and a distribution of the optical information within that elongated blur spot which permits multiple, different signals to be detected from within that elongated blur spot, and

wherein the microlens means include wideband, non-dispersive microlenses in outer, peripheral portions of the image plane and the certain ones of the microlens means and integral dispersion means include high resolution, dispersive microlenses in the central portion of the image plane.

30. The invention defined in claim 29 wherein there is no dead, optically inactive zone between the microlenses in the microlens array and wherein the dispersive microlenses in the central portion of the image plane have a hexagonal configuration.

31. Apparatus for transmitting and concentrating optical information contained in optical blur spots in an image plane to small fractions of the areas of related pixels in a detector plane which is spaced from the image plane, said apparatus comprising,

microlens means, positioned at a plurality of image plane blur spot locations, for transmitting and concentrating the optical information in an image plane blur spot into a smaller detector plane blur spot in a related pixel in the detector plane, so that the area of the detector plane blur spot is decoupled from the area of the pixel, and for producing a contrast ratio, fill factor and optical gain of said optical information in the detector plane blur spot with respect to any existing, unwanted noise present at the detector plane,

said microlens means including dispersion means formed integrally on said microlens means for dispersing the optical information in at least certain ones of the image plane blur spots to create an elongation of a related detector plane blur spot and a distribution of the optical information within that elongated blur spot which permits multiple, different signals to be detected from within that elongated blur spot,

said microlens means including an array of individual, dispersive microlenses and wherein the dispersion means comprise a blazed grating formed integrally and in a regular pattern on each individual, dispersive microlens, and wherein the individual dispersive microlenses are arranged in rows in the array, and wherein the grating pattern of each individual, dispersive microlens in a particular row is rotated at an angle with respect to the axis of that row to reduce optical cross talk noise between adjacent pixels in the detector plane.

32. The invention defined in claim 31 wherein the individual, dispersive microlenses in adjacent rows are longitudinally offset from one another to reduce optical cross talk noise between adjacent pixels in the detector plane.

33. Apparatus for transmitting and concentrating optical information contained in optical blur spots in an image plane to small fractions of the areas of related pixels in a detector plane which is spaced from the image plane, said apparatus comprising,

microlens means, positioned at a plurality of image plane blur spot locations, for transmitting and concentrating the optical information in an image plane blur spot into a smaller detector plane blur spot in a related pixel in the detector plane, so that the area of the detector plane blur spot is decoupled from the area of the pixel, and for producing a contrast ratio, fill factor and optical gain of said optical information in the detector plane blur spot with respect to any existing, unwanted noise present at the detector plane,

said microlens means including dispersion means formed integrally on said microlens means for dispersing the optical information in at least certain ones of the image plane blur spots to create an elongation of a related detector plane blur spot and a distribution of the optical information within that elongated blur spot which permits multiple, different signals to be detected from within that elongated blur spot,

said microlens means including an array of individual, dispersive microlenses and wherein the dispersion means comprise a blazed grating formed integrally and in a regular pattern on each individual, dispersive microlens, and wherein the individual dispersive microlenses are arranged in rows in the array, and wherein the individual, dispersive microlenses in adjacent rows are longitudinally offset from one another to reduce optical cross talk noise between adjacent pixels in the detector plane.

34. Wavelength combining apparatus for combining a plurality of different emitted wavelengths of light, emitted from a plurality of emitters within an emitter plane blur spot, into a bandwidth of light within a unitary, dispersive microlens apparatus, said wavelength combining apparatus comprising,

emitter means in an emitter plane blur spot for emitting a plurality of separate wavelengths or wavebands of light to be combined into a bandwidth of light within a unitary, dispersive microlens apparatus,

unitary, dispersive microlens apparatus positioned at a distance from the emitter plane which is effective to permit the unitary, dispersive microlens apparatus to receive the light from the emitter means and to form the light into the bandwidth of light at the location of the microlens apparatus,

said microlens apparatus including a microlens and a grating formed integrally on said microlens for combining all of the separate emitted wavelengths or wavebands into a single bandwidth of light so that the multicolor emitted wavelengths appear as a single composite color at the surface of the unitary, dispersive microlens apparatus, and wherein the unitary construction of the grating integrally on the microlens enables one unitary, dispersive microlens apparatus to perform multiple, designed, refraction and dispersion functions while eliminating noise and reflection losses which could otherwise occur across an interface between a separated, non-unitary microlens and grating.

35. The invention defined in claim 34 wherein said emitter plane blur spot is an elongated blur spot so related to the dispersion means that the wavelengths of emitted light can be varied from one end of the elongated blur spot to the other end.

36. The invention defined in claim 35 wherein the emitter means include a plurality of emitters within the elongated blur spot with each emitter generating a selected wavelength and/or band of wavelengths which is unique to that emitter and which is within said certain bandwidth and with each emitter positioned in the elongated blur spot at a location correlated to the wavelength emitted by that emitter.

37. The invention defined in claim 36 including energizing means for energizing the emitters to beam light at the selected wavelengths from the emitters to the dispersive microlens apparatus.

38. The invention defined in claim 37 wherein the energizing means include modulating means for modulating the output of the emitters and for thereby controlling the wavelengths present in said bandwidth at the image plane blur spot and also the relative energy levels of the different wavelengths which are present in said bandwidth at the image plane blur spot.

39. Apparatus for combining a plurality of different emitted wavelengths of light, emitted from a plurality of emitters within an emitter plane blur spot, into a bandwidth of light at an image plane blur spot, said apparatus comprising,

emitter means in an emitter plane blur spot for emitting a plurality of separate wavelengths or wavebands of light to be combined into a bandwidth of light at an image plane blur spot,

microlens means positioned at an image plane at a distance from the emitter plane which is effective to permit the microlens means to receive the light from the emitter means and to form the light into an image plane blur spot at the location of the microlens means,

said microlens means including dispersion means formed integrally on said microlens means for combining all of the separate, emitted wavelengths or wavebands into a single bandwidth of light in the image plane blur spot so that the multicolor emitted wavelengths appear as a single composite color at the surface of the microlens means, and

wherein said emitter plane blur spot is an elongated blur spot so related to the dispersion means that the wavelengths of emitted light can be varied from one end of the elongated blur spot to the other end, and

wherein the emitter means include a plurality of emitters within the elongated blur spot with each emitter generating a selected wavelength and/or band of wavelengths which is unique to that emitter and which is within said certain bandwidth and with each emitter positioned in the elongated blur spot at a location correlated to the wavelength emitted by that emitter, and

including energizing means for energizing the emitters to beam light at the selected wavelengths from the emitters to the dispersive microlens means, and

wherein the energizing means include modulating means for modulating the output of the emitters and for thereby controlling the wavelengths present in said bandwidth at the image plane blur spot and also the relative energy levels of the different wavelengths which are present in said bandwidth at the image plane blur spot, and

wherein the emitters include three emitters for emitting red, green and blue color information.

40. The invention defined in claim 39 including processing means for using the color information as combined in the image plane blur spot for color transmitting and regenerating apparatus, such as color television, color recording, color facsimile, and color printing.

41. Apparatus for processing color information using at least two separate arrays of dispersion microlenses, said apparatus comprising,

(a) color generating and combining means for generating an organized pattern of color information made up from a plurality of individual, image plane blur spots, said color generating and combining means comprising,

an emitter plane having a plurality of individual, emitter plane blur spots,

emitter means in each emitter plane blur spot for emitting a plurality of separate wavelengths or wavebands of light to be combined into a bandwidth of light at a related image plane blur spot,

first microlens means comprising a first array of individual microlenses positioned at an image plane at a distance from the emitter plane which is effective to permit each individual microlens to receive the light from the emitter means in a related emitter plane blur spot and to form the light into an image plane blur spot at the location of the individual microlens,

said first microlens means including dispersion means formed integrally on each individual microlens for combining all of the separate, emitted wavelengths or wavebands, emitted from a related emitter plane blur spot, into a single bandwidth of light in the image plane blur spot so that the multicolor, emitted wavelengths appear as a single composite color at the surface of the individual microlens,

(b) color dispersing and detecting means for detecting component wavelengths or wavebands of color contained within individual bandwidths of color in individual, image plane blur spots, which image plane blur spots collectively make up an organized pattern of color information,

said color dispersing and detecting means comprising,

an image plane having a plurality of individual, image plane blur spots,

a detector plane having a plurality of individual pixels with each pixel having a small but elongated pixel blur spot area,

second microlens means comprising a second array of individual microlenses with each individual microlens positioned at a related, individual, image plane blur spot,

said second microlens means including dispersion means formed integrally on each individual microlens for dispersing the bandwidth of color in the related image plane blur spot to a related pixel blur spot area and for producing an elongated pixel blur spot in which the wavelengths are varied from one end to the other, and

detector means in each pixel blur spot for detecting multiple, different colors from the elongated pixel blur spot, and

(c) transmitting means for transmitting the organized pattern of color information bidirectionally between the color generating and combining means and the color dispersing and detecting means.

42. A method of transmitting and concentrating optical information contained in optical blur spots in an image plane to small fractions of the areas of related pixels in a detector plane which is spaced from the image plane, said method comprising,

positioning a microlens at an image plane blur spot for transmitting and concentrating the optical information in the image plane blur spot into a smaller detector plane blur spot in a related pixel in the detector plane, so that the area of the detector plane blur spot is decoupled from the area of the pixel, and for producing a contrast ratio, fill factor and optical gain of said optical information in the detector plane blur spot with respect to any existing, unwanted noise present at the detector plane,

dispersing the optical information in the image plane blur spot through a related microlens having a dispersion producing diffraction grating formed integrally on the microlens which is effective to create an elongation of a related detector plane blur spot and a dispersed distribution of the optical information to specific locations within that elongated, detector plane blur spot and which distribution of the optical information permits multiple, different signals to be detected by detectors at the specific locations within that elongated, detector plane blur spot, and

detecting multiple, different signals at the specific locations from the optical information in the elongated, detector plane blur spot to thereby permit real time discrimination of the optical information for certain qualities, such as, for example, the color and/or temperature, of the object or objects generating the optical information, and wherein the unitary construction of the grating integrally on the microlens enables one unitary, dispersive microlens to perform multiple, designed, refraction and dispersion functions while eliminating noise and reflection losses which could otherwise occur across an interface between a separated, non-unitary microlens and grating.

43. A method of combining a plurality of different emitted wavelengths of light, emitted from a plurality of emitters within an emitter plane blur spot, into a bandwidth of light at an image plane blur spot, said method comprising,

emitting from a plurality of specific locations in an elongated emitter plane blur spot a plurality of separate wavelengths or wavebands of light to be combined into a bandwidth of light within a unitary dispersive microlens apparatus,

positioning a unitary dispersive microlens apparatus comprising a microlens and a grating formed integrally on the microlens at an image plane at a distance from the emitter plane which is effective to permit the unitary microlens apparatus to receive the light emitted from the emitter plane blur spot and to form the light into an image plane blur spot at the location of the unitary microlens apparatus,

combining all of the separate, emitted wavelengths or wavebands into a single bandwidth of light in the image plane blur spot by the grating formed integral on the microlens and so related to locations of the emitted wavelengths or wavebands in the elongated emitter plane blur spot that the multicolor emitted wavelengths appear as a single composite color at the surface of the unitary dispersive microlens apparatus.