Output efficiency control device, projection-type display apparatus, infrared sensor, and non-contact thermometer

• US 6,072,620 A
• Filed: 06/25/1997
• Issued: 06/06/2000
• Est. Priority Date: 11/01/1995
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ueda, Michihito, Shiono, Teruhiro, Ito, Tatsuo, Yokoyama, Kazuo
• Primary Examiner(s): BURKE, MARGARET A
• Application Number:
  US08/860,253
• Time in Patent Office: 1,077 Days
• Field of Search: 359/237, 359/245-247, 359/254, 359/276, 359/277, 359/288, 359/289, 359/355, 359/356, 359/357, 359/572, 359/573, 359/290, 359/291, 359/295, 359/558, 359/619, 250/338.3, 345/566, 345/108, 349/95
• US Class Current: 359/290
• CPC Class Codes: G02B 3/0018 Reflow, i.e. characterized by the step of melting microstructures to form curved surfaces, e.g. manufacturing of moulds and surfaces for transfer etching
• 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: G02F 1/0102 Constructional details, not otherwise provided for in this subclass

Abstract

Microlenses 3a and 3b are formed on a first surface of a transparent substrate, and an output efficiency control device 2 which modulates a light amount of incident light is provided on a second surface opposing the first surface. Incident light 4 is made to be incident obliquely to an optical axis of the microlens 3a, to be focused on the output efficiency control device 2. The output efficiency control device 2 modulates a light amount of incident light and outputs the light as outgoing light 5 through the microlens 3b. Because of such a structure, the output efficiency control device 2 can be decreased in size, compared with a diameter of a beam and an aperture of a microlens.

Claims

1. An optical modulator comprising:

a device which is electrically controllable to modulate light which is incident thereupon;

first focusing means for focusing the light onto the device without separating the light with respect to wavelength; and

second focusing means for outputting the light modulated by the device without separating the light with respect to the wavelength,

wherein the first and second focusing means are disposed adjacent each other opposite the device;

wherein the light incident upon the device is incident onto the first focusing means in a direction oblique to an optical axis of the first focusing means.

2. An optical modulator according to claim 1, wherein the device is a reflection-type optical element.

3. An optical modulator according to claim 1, wherein the first focusing means and the second focusing means are formed on an identical surface of a substrate.

4. An optical modulator according to claim 1, further comprising a transparent substrate having a first surface and a second surface opposing each other,

wherein the first focusing means and the second focusing means are formed on the first surface of the transparent substrate, and the device is a reflection-type optical element formed on the second surface of the transparent substrate.

5. An optical modulator comprising:

a device which modulates light which is incident thereupon;

first focusing means for focusing light onto the device without separating the light with respect to wavelength;

second focusing means for outputting the light modulated by the device without separating the light with respect to the wavelength; and

a transparent substrate having a first surface and a second surface opposing each other;

wherein the first and second focusing means are disposed adjacent each other opposite the device;

wherein the first focusing means and the second focusing means are formed on the first surface of the transparent substrate, and the device is a reflection-type optical element formed on the second surface of the transparent substrate;

wherein the device comprises;

a transparent electrode which functions as a first electrode, formed on the second surface of the transparent substrate;

a first grating formed on the transparent electrode;

a spacer layer formed on the transparent electrode; and

a second grating composed of a plurality of beams having a portion which functions as a second electrode, both ends of the beams being supported on the spacer layer,

wherein a distance between the transparent electrode and the second grating is varied by adjusting a voltage applied between the first electrode and the second electrode, thereby controlling an efficiency at which the light focused by the first focusing means is output to the second focusing means.

6. An optical modulator according to claim 5, wherein the device further includes an insulating layer provided on the first grating.

7. An optical modulator comprising:

a device which modulates light which is incident thereupon;

first focusing means for focusing light onto the device without separating the light with respect to wavelength; and

second focusing means for outputting the light modulated by the device without separating the light with respect to the wavelength;

wherein the first and second focusing means are disposed adjacent each other opposite the device;

wherein the light incident upon the device is incident onto the first focusing means in a direction oblique to an optical axis of the first focusing means;

wherein the first focusing means and the second focusing means are formed on an identical surface of a substrate;

wherein the first and second focusing means have an identical shape, and

wherein the device is disposed with a center thereof positioned at a point of intersection of a line vertical to a plane on which the first focusing means and the second focusing means are formed, extending from a center of a straight line connecting a center of the first focusing means and a center of the second focusing means, and a plane on which the device is formed.

8. An optical modulator comprising:

a device which modulates light which is incident thereupon;

first focusing means for focusing light onto the device without separating the light with respect to wavelength; and

second focusing means for outputting the light modulated by the device without separating the light with respect to the wavelength;

wherein the first and second focusing means are disposed adjacent each other opposite the device;

wherein the light incident upon the device is incident onto the first focusing means in a direction oblique to an optical axis of the first focusing means;

wherein the first focusing means and the second focusing means formed on an identical surface of a substrate; and

wherein the first focusing means and the second focusing means have a similar elliptical shape in which a cross-section in a thickness direction gradually decreases and are arranged in a major axis direction thereof.

9. An optical modulator according to claim 8, wherein, assuming that an incident angle of an optical axis of the light incident on the first focusing means with respect to a vertical direction of a plane on which the first focusing means and the second focusing means are formed is θ

, a size ratio of the major axis of the ellipsoid to a minor axis is 1/cos θ

.

10. An optical modulator comprising:

a device which modulates light which is incident thereupon;

first focusing means for focusing light onto the device without separating the light with respect to wavelength; and

second focusing means for outputting the light modulated by the device without separating the light with respect to the wavelength;

wherein the first and second focusing means are disposed adjacent each other opposite the device;

wherein the light incident upon the device is incident onto the first focusing means in a direction oblique to an optical axis of the first focusing means;

wherein the device is a movable mirror.

11. An optical modulator, comprising:

output efficiency control means for modulating light which is incident thereupon;

first focusing means for focusing the light onto the output efficiency control means; and

second focusing means for outputting the light modulated by the output efficiency control means,

wherein the first focusing means and the second focusing means are formed on an identical surface of a substrate, are disposed so as to oppose the output efficiency control means, and are diffraction-type microlenses having a binary/multi-level structure.

12. An optical modulator, comprising:

output efficiency control means for modulating light which is incident thereupon;

first focusing means for focusing the light onto the output efficiency control means;

second focusing means for outputting the light modulated by the output efficiency control means, and

a transparent substrate having a first surface and a second surface opposing each other,

wherein the first focusing means and the second focusing means are disposed so as to oppose the output efficiency control means, are formed on the first surface of the transparent substrate, and are square lenses each having a rectangular aperture,

the output efficiency control means is a reflection-type optical element formed on the second surface of the transparent substrate and comprises;

a transparent electrode which functions as a first electrode, formed on the second surface of the transparent substrate;

a first grating formed on the transparent electrode;

a spacer layer formed on the transparent electrode; and

a second grating composed of a plurality of beams having a portion which functions as a second electrode, both ends of the beams being supported on the spacer layer,

wherein a distance between the transparent electrode and the second grating is varied by adjusting a voltage applied between the first electrode and the second electrode, thereby controlling an efficiency at which the light focused by the first focusing means is output to the second focusing means; and

wherein an interval between the plurality of beams in the second grating of the output efficiency control means gradually increases in a longitudinal direction of the beams.

13. An optical modulator according to claim 12, wherein a period of the grating increases according to a linear function in a longitudinal direction of the grating.

14. An optical modulator according to claim 12, wherein lengths of the plurality of beams are equal in the second grating.

15. An optical modulator according to claim 12, wherein the first grating and the second grating of the output efficiency control means are designed in such a manner that a portion of the grating having a smallest period is 7 times or more a wavelength of the incident light.

16. An optical modulator according to claim 15, wherein, assuming that a length of one side of the lens is L, a focal length of the lens is f, and an angle formed by a normal to a principal plane of the plate of the output efficiency control device and the optical axis of the lens is θ

, the first grating and the second grating are designed in such a manner that a portion of the grating having a largest period becomes 7(2f+L tan θ

)/(2f-L tan θ

) times or more the wavelength of the incident light.

17. A display apparatus comprising:

a light source;

splitting means for splitting light emitted from the light source into a plurality of colored light beams having wavelength ranges different from each other;

a plurality of optical modulators, provided in, optical paths of the plurality of colored light beams, respectively, for modulating the plurality of colored light beams, respectively; and

an imaging lens for imaging the plurality of colored light beams modulated by the plurality of optical modulators,

wherein each of the plurality of optical modulators includes;

a plurality of output efficiency control means arranged in an array, for modulating a corresponding colored light beam of the plurality of colored light beams; and

focusing means having a plurality of focusing elements arranged in an array, the corresponding colored light beam is incident upon the focusing means in a direction oblique to an optical axis of the focusing means and is focused on the output efficiency control means, and the modulated corresponding colored light beam is output in an oblique direction through the focusing means.

18. A display apparatus according to claim 17, wherein an incident angle at which the colored light beam is incident upon the focusing means is equal to an angle at which the colored light beam is output from the focusing means,

an interval at which the plurality of output efficiency control means are arranged is equal to an interval at which the plurality of focusing elements are arranged in the focusing means, and

the plurality of output efficiency control means are disposed so as to be shifted by a half of the arrangement interval with respect to the focusing means in a direction in which an incident direction of the colored light beam is tilted with respect to the optical axis of the focusing means.

19. A display apparatus according to claim 17, wherein each of the plurality of output efficiency control means is disposed so as to oppose a pair of focusing elements adjacent to each other of the plurality of focusing elements of the focusing means, receives the corresponding colored light beam from one of the pair of focusing elements, and outputs the modulated corresponding colored light beam to the other one of the pair of focusing elements.

20. A display apparatus according to claim 17, wherein the plurality of output efficiency control means are arranged in an m-row and n-column two-dimensional array, the plurality of focusing elements are arranged in an (m+1)-row and n-column two-dimensional array in the focusing means, and output efficiency control means on a k-th row is disposed so as to correspond to a focusing element on a k-th row and a focusing element on a (k+1)th row.

21. A display apparatus according to claim 17, wherein the plurality of optical modulators include a transparent substrate having a first surface on which the focusing means is formed and a second surface opposing the first surface, and the output efficiency control means is a reflection-type optical element formed on the second surface.

22. A display apparatus according to claim 21, wherein each of the plurality of output efficiency control means includes:

a transparent electrode which functions as a first electrode, provided on the second surface of the transparent substrate;

a first grating formed on the transparent electrode;

a spacer layer formed on the transparent electrode; and

a second grating composed of a plurality of beams having a portion which functions as a second electrode, both ends of the beams being supported on the spacer layer,

wherein a distance between the transparent electrode and the second grating is varied by adjusting a voltage applied between the first electrode and the second electrode, thereby an efficiency at which the corresponding colored light beam is output to the focusing means is controlled.

23. A display apparatus according to claim 17, wherein the plurality of focusing elements have a similar elliptical shape in which a cross-section gradually decreases in a thickness direction thereof.

24. A display apparatus according to claim 23, wherein assuming that an angle of an optical axis of the corresponding colored light beam incident upon the focusing means with respect to a vertical direction of a plane on which the focusing means is formed is θ

, a size ratio of a major axis of the ellipsoid to a minor axis is 1/cos θ

.

25. A display apparatus according to claim 17, wherein the splitting means has a first splitting element which reflects a blue light beam and transmits the other light beams, a second splitting element which reflects a green light beam and transmits the other light beams, and a third splitting element which reflects a red light beam and transmits the other light beams.

26. A display apparatus according to claim 25, wherein a wavelength bandwidth of light reflected from the first splitting element is smaller than wavelength bandwidths of light reflected from the second splitting element and the third splitting element.

27. A display apparatus according to claim 25, wherein a wavelength bandwidth of light reflected from the third splitting element is larger than wavelength bandwidths of light reflected from the first splitting element and the second splitting element.

28. A display apparatus according to claim 25, wherein a wavelength bandwidth of reflected light decreases in the order of the third splitting element, the second splitting element, and the first splitting element.

29. A display apparatus according to claim 25, wherein the light emitted from the light source passes through the first splitting element, the second splitting element, and the third splitting element in this order.

30. A display apparatus according to claim 22, wherein each of the plurality of optical modulators further has a control circuit of the output efficiency control means, and the second electrode of each of the output efficiency control means is connected to a connecting electrode of the control circuit via a solder bump.

31. A display apparatus according to claim 21, wherein each of the plurality of optical modulators further has light absorbing means provided in a region of the transparent substrate other than a region thereof where the focusing means and the plurality of output efficiency control means are formed.

32. A display apparatus according to claim 31, wherein the light absorbing means is also provided on each periphery of the plurality of focusing elements.

33. A display apparatus according to claim 22, wherein the output efficiency control means outputs zero-th order diffracted light of the corresponding colored light beam.

34. A display apparatus according to claim 17, wherein the plurality of output efficiency control means are a movable mirror array.

35. A display apparatus according to claim 22, wherein the focusing means is a diffraction-type microlens array having a binary/multi-level structure.

36. A display apparatus according to claim 22, wherein, in the second grating, an interval of the plurality of beams gradually increases in a longitudinal direction of the beams.

37. A display apparatus according to claim 36, wherein a period of the grating increases according to a linear function in a longitudinal direction of the grating.

38. A display apparatus according to claim 36, wherein, in the second grating, lengths of the plurality of beams are equal.

84. A method for producing the display apparatus of claim 17, comprising the steps of:

producing the plurality of optical modulators; and

arranging and assembling the light source, the splitting means, the plurality of optical modulators, and the imaging lens,

wherein the step of producing the plurality of optical modulators includes;

forming the focusing means on a first surface of a transparent substrate;

forming the plurality of output efficiency control means each having a connecting portion for driving on a second surface of the transparent substrate opposing the first surface;

connecting the connecting portion for driving to a driving circuit for driving the plurality of output efficiency control means;

in the case where there is a connection defect between the connecting portion for driving and the driving circuit, irradiating the connecting portion corresponding to the connection defect with laser light, thereby repairing the connection defect.

39. An output efficiency control device which modulates incident light and outputs the modulated light, comprising:

a plate having a portion which functions as a first electrode;

a spacer layer formed on the plate; and

a grating composed of a plurality of beams which are not parallel to each other, the beams having portions which function as second electrodes, both ends of the beams being supported on the spacer layer,

wherein a distance between the grating and the plate is varied by adjusting a voltage applied between the first electrode and the second electrodes, thereby an output efficiency of the light is controlled.

40. An output efficiency control device according to claim 39, wherein a period of the grating gradually increases in a longitudinal direction of the grating.

41. An output efficiency control device according to claim 40, wherein the period of the grating increases according to a linear function in a longitudinal direction of the grating.

42. An output efficiency control device according to claim 40, wherein lengths of the plurality of beams are equal.

43. An output efficiency control device according to claim 39, wherein the plurality of beams of the grating are aligned on an identical plane when a voltage is not applied between the first electrode and the second electrodes, and every other beam is attracted to this plate when a voltage is applied, thereby the output efficiency is controlled.

44. An output efficiency control device according to claim 43, wherein the plurality of beams are densely aligned and function as a mirror when a voltage is not applied between the first electrode and the second electrodes.

45. An output efficiency control device according to claim 39, wherein, assuming that a wavelength of the incident light is λ

, and an angle formed by a normal of a principal plane of the plate of the output efficiency control device and an optical axis of the incident light is θ

, an operation distance of the grating is set to be mλ

/(4 cos θ

), where m is an integer.

46. An output efficiency control device according to claim 39, wherein, assuming that a wavelength of the incident light is λ

, and an angle formed by a normal to a principal plane of the plate of the output efficiency control device and an optical axis of the incident light is θ

, a thickness of the beams is set to be mλ

/(4 cos θ

), where m is an integer.

47. An output efficiency control device according to claim 39, further comprising a reflective film formed on a surface of the plate and a surface of the grating.

48. An output efficiency control device according to claim 39, further comprising an insulating film formed between the plate and the grating.

49. An output efficiency control device according to claim 48, further comprising a reflective film formed on a surface of the insulating layer and a surface of the grating.

50. An infrared sensor comprising:

a lens for focusing infrared light;

a pyro-electric element; and

the output efficiency control device of claim 39, which receives the infrared light focused by the lens and outputs at least part of the infrared light to the pyro-electric element.

51. An infrared sensor according to claim 50, wherein the pyro-electric element has a rectangular surface.

52. An infrared sensor according to claim 51, wherein the lens has a rectangular aperture.

53. An infrared sensor according to claim 50, wherein the output efficiency control device is obliquely disposed in such a manner that a normal to a principal plane of the plate is disposed so as not to be parallel to an optical axis of the lens.

54. An infrared sensor according to claim 50, wherein the output efficiency control device is disposed in such a manner that only zero-th order diffracted light of diffracted light diffracted by the grating of the output efficiency control device is incident upon the pyro-electric element and diffracted light other than the zero-th order diffracted light is not incident upon the pyro-electric element.

55. An infrared sensor according to claim 50, wherein a change in a distance between the grating and the plate of the output efficiency control device changes a light amount of the zero-th order diffracted light.

56. An infrared sensor according to claim 50, wherein the infrared sensor further includes a sealing member having an opening, and the sealing member contains the output efficiency control device and the pyro-electric element.

57. An infrared sensor according to claim 56, wherein the lens is provided in the opening of the sealing member.

58. An infrared sensor according to claim 50, wherein the lens is a diffraction-type lens.

59. An infrared sensor according to claim 52, wherein a smallest period of the grating of the output efficiency control device is 7 times or more a wavelength of the infrared light.

60. An infrared sensor according to claim 52, wherein, assuming that a length of one side of the lens is L, a focal length of the lens is f, and an angle formed by a normal to a principal plane of the plate of the output efficiency control device and an optical axis of the lens is θ

, a largest period of the grating is 7(2f+L tan θ

)/(2f-L tan θ

) times or more a wavelength of the infrared light.

61. An infrared sensor according to claim 50, wherein the output efficiency control device is disposed in such a manner that a direction which is parallel to a principal plane of the plate and vertical to the grating is vertical to an optical axis of the lens.

62. An infrared sensor comprising:

the output efficiency control device of claim 39, which outputs at least part of incident infrared light;

a pyro-electric element; and

a lens, provided between the output efficiency control device and the pyro-electric element, for focusing the infrared light output from the output efficiency control device onto the pyro-electric element.

63. An infrared sensor according to claim 62, wherein the pyro-electric element has a rectangular surface.

64. An infrared sensor according to claim 63, wherein the lens has a rectangular aperture.

65. An infrared sensor according to claim 62, wherein the output efficiency control device is obliquely disposed in such a manner that a normal to a principal plane of the plate is not parallel to an optical axis of the lens.

66. An infrared sensor according to claim 62, wherein the output efficiency control device is disposed in such a manner that only zero-th order diffracted light of diffracted light diffracted by the grating of the output efficiency control device is incident upon the pyro-electric element, and diffracted light other than the zero-th order diffracted light is not incident upon the pyro-electric element.

67. An infrared sensor according to claim 62, wherein a change in a distance between the grating and the plate of the output efficiency control device changes a light amount of the zero-th order diffracted light.

68. An infrared sensor according to claim 62, wherein the infrared sensor further includes a sealing member having an opening, and the sealing member contains the output efficiency control device and the pyro-electric element.

69. An infrared sensor according to claim 62, wherein the lens has a surface relief structure in accordance with a modulated amount of a phase of the lens and is composed of a material selected from a group consisting of Si, Ge, GaAs, InP, GaP, ZnSe, and ZnS.

70. An infrared sensor according to claim 62, wherein the output efficiency control device is disposed in such a manner that a direction which is parallel to a principal plane of the plate and vertical to the grating is vertical to an optical axis of the lens.

76. A non-contact thermometer comprising:

a lens for focusing infrared light;

a housing having an opening;

a shield which closes and opens the opening;

a pyro-electric element provided in the housing;

contact-type temperature measuring means provided on a side wall of the housing; and

the output efficiency control device of claim 39, which is provided in the housing, receives the infrared light focused by the lens, and outputs at least part of the infrared light.

77. A non-contact thermometer according to claim 76, wherein the contact-type temperature measuring means is a thermocouple.

78. A non-contact thermometer comprising:

a housing having an opening;

a shield which closes and opens the opening;

a pyro-electric element provided in the housing;

contact-type temperature measuring means provided on a side wall of the housing;

the output efficiency control device of claim 39, which is provided in the housing, receives infrared light through the opening, and outputs at least part of the infrared light; and

a lens which outputs at least part of the infrared light output from the output efficiency control device to the pyro-electric element.

79. A non-contact thermometer according to claim 78, wherein the contact-type temperature measuring means is a thermo-couple.

71. An output efficiency control device array which modulates incident light and outputs the modulated light, having a plurality of output efficiency control devices arranged in a two-dimensional array, each of the plurality of output efficiency control devices comprising:

a plate having a portion which functions as a first electrode;

a spacer layer formed on the plate; and

a grating composed of beams which are not parallel to each other, the beams having portions which function as second electrodes, both ends of the beams being supported on the spacer layer,

wherein a distance between the grating and the plate is varied by adjusting a voltage applied between the first electrode and the second electrodes, thereby an efficiency at which the light is output is controlled.

72. An infrared sensor comprising:

a lens for focusing infrared light;

a pyro-electric element; and

the output efficiency control device array of claim 71, which receives the infrared light focused by the lens and outputs at least part of the infrared light to the pyro-electric element.

73. An infrared sensor, comprising:

the output efficiency control device array of claim 71, which outputs at least part of incident infrared light;

a pyro-electric element; and

a lens, provided between the output efficiency control device and the pyro-electric element, for focusing the infrared light output from the output efficiency control device onto the pyro-electric element.

74. A method for driving the infrared sensor of claim 72, comprising the steps of:

successively operating the plurality of output efficiency control devices, and successively detecting output signals from the pyro-electric element thus obtained; and

detecting a two-dimensional infrared light intensity distribution as information in time sequence, based on the detected output signals from the pyro-electric element.

75. A method for driving the infrared sensor of claim 73, comprising the steps of:

successively operating the plurality of output efficiency control devices, and successively detecting output signals from the pyro-electric element thus obtained; and

detecting a two-dimensional infrared light intensity distribution as information in time sequence, based on the detected output signals from the pyro-electric element.

80. A non-contact thermometer comprising:

a lens for focusing infrared light;

a housing having an opening;

a shield which closes and opens the opening;

a pyro-electric element provided in the housing;

contact-type temperature measuring means provided on a side wall of the housing; and

the output efficiency control device array of claim 71, which is provided in the housing, receives the infrared light focused by the lens, and outputs at least part of the infrared light.

81. A non-contact thermometer according to claim 80, wherein the contact-type temperature measuring means is a thermo-couple.

82. A non-contact thermometer comprising:

a housing having an opening;

a shield which closes and opens the opening;

a pyro-electric element provided in the housing;

contact-type temperature measuring means provided on a side wall of the housing;

the output efficiency control device of claim 71, which is provided in the housing, receives infrared light incident through the opening, and outputs at least part of the infrared light; and

a lens which outputs at least part of the infrared light output from the output efficiency control device to the pyro-electric element.

83. A non-contact thermometer according to claim 82, wherein the contact-type temperature measuring means is a thermo-couple.

85. An optical modulator comprising:

a device which modulates light which is incident thereupon;

first focusing means for focusing light onto the device without separating the light with respect to wavelength; and

second focusing means for outputting the light modulated by the device without separating the light with respect to the wavelength;

wherein the first and second focusing means are disposed adjacent each other opposite the device;

wherein the light incident upon the device is incident onto the first focusing means in a direction oblique to an optical axis of the first focusing means, and the output light is output from the second focusing means in a direction oblique to an optical axis of the second focusing means.