Double substrate reflective spatial light modulator with self-limiting micro-mechanical elements
First Claim
Patent Images
1. A spatial light modulator, comprising:
- a substrate that is transmissive to visible light;
a silicon substrate;
wherein the silicon substrate and the substrate that is transmissive to visible light are bonded together with a spacer therebetween forming a gap between the substrates; and
a plurality of deflectable elements encapsulated within the gap.
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Accused Products
Abstract
A spatial light modulator includes an upper optically transmissive substrate held above a lower substrate containing addressing circuitry. One or more electrostatically deflectable elements are suspended by hinges from the upper substrate. In operation, individual mirrors are selectively deflected and serve to spatially modulate light that is incident to, and the reflected back through, the upper substrate. Motion stops may be attached to the reflective deflectable elements so that the mirror does not snap to the bottom substrate. Instead, the motion stop rests against the upper substrate thus limiting the deflection angle of the reflective deflectable elements.
85 Citations
88 Claims
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1. A spatial light modulator, comprising:
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a substrate that is transmissive to visible light;
a silicon substrate;
wherein the silicon substrate and the substrate that is transmissive to visible light are bonded together with a spacer therebetween forming a gap between the substrates; and
a plurality of deflectable elements encapsulated within the gap. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
a dielectric layer.
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5. The spatial light modulator of claim 4, wherein the substrate that transmissive to visible light further comprises:
another dielectric layer, wherein said another dielectric layer has an optical index different from that of the dielectric layer.
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6. The spatial light modulator of claim 1, wherein the substrate that is transmissive to visible light is glass.
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7. The spatial light modulator of claim 1, wherein the substrate that is transmissive to visible light is quartz.
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8. The spatial light modulator of claim 1, further comprising:
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a first pattern on the substrate that is transmissive to visible light;
a second pattern on the silicon substrate; and
wherein the first and second patterns are aligned together when the substrates are bonded together.
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9. The spatial light modulator of claim 1, wherein the spacer is surrounded by a plurality of deflectable elements;
- and wherein each of the plurality of deflectable elements has an edge coplanar with a corresponding edge of the spacer.
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10. The spatial light modulator of claim 1, wherein the substrates are bonded together with the spacer therebetween using an adhesive.
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11. The spatial light modulator of claim 10, wherein the adhesive is epoxy.
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12. The spatial light modulator of claim 1, wherein the substrates are aligned together such that each deflectable element is aligned with an electrode.
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13. The spatial light modulator of claim 1, wherein the spacer is positioned outside the plurality of deflectable elements.
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14. The spatial light modulator of claim 1, wherein the deflectable elements are minor plates.
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15. The spatial light modulator of claim 1, where in the deflectable element comprises a ceramic material.
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16. The spatial light modulator of claim 15, wherein the ceramic material is silicon dioxide or silicon nitride.
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17. The spatial light modulator of claim 16, wherein the deflectable element comprises a light reflection layer.
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18. The spatial light modulator of claim 14, wherein each mirror plate is attached to a hinge such that the mirror plate is operable to rotate.
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19. The spatial light modulator of claim 18, wherein the hinge is a torsion hinge.
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20. The spatial light modulator of claim 18, wherein the mirror plate comprise a first and second portions such that during the rotation of the mirror plate, the second portion moves towards the glass substrate and the first portion moves away from the glass substrate;
- and wherein the hinge and the mirror plate are positioned in different planes.
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21. A spatial light modulator, comprising:
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a first substrate having a plurality of micromirrors and a spacer that is positioned within the plurality of micromirrors; and
a second substrate having an array of electrodes and circuitry, wherein the first and second substrates are bonded together with the spacer between the fist and second substrates. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
a dielectric layer.
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27. The spatial light modulator of claim 26, wherein the first substrate further comprises:
another dielectric layer, wherein said another dielectric layer has an optical index different from that of the dielectric layer.
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28. The spatial light modulator of claim 22, further comprising:
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a first pattern on the first substrate;
a second pattern on the second substrate; and
wherein the first and second patterns are aligned together when the substrates are bonded together.
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29. The spatial light modulator of claim 21, wherein the spacer is surrounded by a plurality of micromirrors, each of which has an edge coplanar with a corresponding edge of the spacer.
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30. The spatial light modulator of claim 21, wherein the substrates are bonded together with the spacer in between using with an adhesive.
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31. The spatial light modulator of claim 30, wherein the adhesive is epoxy.
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32. The spatial light modulator of claim 21, where in the micromirror comprises a ceramic material.
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33. The spatial light modulator of claim 32, wherein the ceramic material is silicon dioxide or silicon nitride.
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34. The spatial light modulator of claim 21, wherein the micromirror comprises a light reflection layer.
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35. The spatial light modulator of claim 34, wherein each micromirror has a mirror plate that is attached to a hinge such that the mirror plate is operable to rotate along a rotation axis.
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36. The spatial light modulator of claim 35, wherein the hinge is a torsion hinge.
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37. The spatial light modulator of claim 35, wherein the mirror plate comprise a first and second portions such that during the rotation of the mirror plate, the second portion moves towards the glass substrate and the first portion moves away from the glass substrate;
- and wherein the mirror plate and the hinge are positioned in different planes.
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38. A spatial light modulator, comprising:
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a first substrate;
a second substrate, wherein the first and the second substrates are bonded together with a spacer therebetween so as to form a gap between the substrates; and
a plurality of micromirrors positioned within the gap, each micromirror further comprising;
a mirror plate, further comprising;
a first and second portions, wherein the second portion moves away from the first substrate when the first portion moves towards the first substrate;
a hinge that is located in a plane other than a plane in which the mirror plate is located; and
wherein the mirror plate is attached to the hinge such that the mirror plate is operable to rotate. - View Dependent Claims (39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54)
a dielectric layer.
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42. The spatial light modulator of claim 40, wherein the first substrate is glass.
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43. The spatial light modulator of claim 40, wherein the first substrate further comprises:
another dielectric layer, wherein said another dielectric layer has an optical index different from that of the dielectric layer.
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44. The spatial light modulator of claim 40, wherein the second substrate is silicon.
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45. The spatial light modulator of claim 44, further comprising:
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a first pattern on the first substrate;
a second pattern on the second substrate; and
wherein the first and second patterns are aligned together when the substrates are bonded together.
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46. The spatial light modulator of claim 38, wherein the spacer is surrounded by a plurality of micromirrors;
- and wherein each of said plurality of micromirrors has an edge coplanar with a corresponding edge of the spacer.
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47. The spatial light modulator of claim 38, wherein the substrates are bonded together with the spacer therebetween using an adhesive.
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48. The spatial light modulator of claim 47, wherein the adhesive is epoxy.
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49. The spatial light modulator of claim 38, wherein the substrates are aligned together such that each micromirror is aligned with an electrode.
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50. The spatial light modulator of claim 38, wherein the spacer is positioned outside the plurality of micromirrors.
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51. The spatial light modulator of claim 38, where in the micromirror comprises a ceramic material.
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52. The spatial light modulator of claim 51, wherein the ceramic material is silicon dioxide or silicon nitride.
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53. The spatial light modulator of claim 51, wherein the mirror plate of the micromirror comprises a light reflection layer.
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54. The spatial light modulator of claim 53, wherein the hinge is a torsion hinge.
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55. A method of modulating light, comprising:
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providing a spatial light modulator that comprises a first and second substrates, the first substrate being optically transmissive and being held above the second substrate, an electrostatically deflectable mirror suspended by a hinge from the optically transmissive substrate, the second substrate containing an electrode and circuitry;
providing an incoming light beam that passes through the optically transmissive substrate and that is reflected by the electrostatically deflectable mirror;
applying a voltage bias between the mirror and the electrode so as to deflect the mirror due to electrostatic attraction; and
deflecting the light beam back through the optically transmissive substrate. - View Dependent Claims (56, 57, 58, 59, 60, 61)
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62. A method of making a spatial light modulator, comprising:
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forming a plurality of micromirror on a first substrate;
forming a plurality of circuitry and electrodes on a second substrate; and
joining the first and second substrates together with a spacer therebetween by bonding with an adhesive. - View Dependent Claims (63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82)
coating an opaque layer on the first substrate, wherein the opaque layer is removed before joining the substrates.
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64. The method of claim 62, wherein the step or forming the micromirrors on the first substrate further comprises:
depositing a dielectric layer on the first substrate.
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65. The method of claim 64, further comprising:
depositing another dielectric layer on the first substrate, wherein said another dielectric layer has an optical index different from that of the dielectric layer.
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66. The method of claim 63, further comprising:
dispensing an adhesive around the edge of the first or the second substrate.
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67. The method of claim 62, further comprising:
dispensing an adhesive around the edge of the first and the second substrate.
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68. The method of claim 62, wherein the step of joining the substrates further comprises:
aligning a pattern on the first substrate to another pattern on the second substrate.
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69. The method of claim 62, wherein the adhesive is epoxy.
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70. The method of claim 62, wherein the first and second substrates are aligned before bonding.
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71. The method of claim 62, wherein the first substrate is a light transmissive substrate.
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72. The method of claim 71, wherein the first substrate is glass.
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73. The method of claim 71, wherein the first substrate is quartz.
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74. The method of claim 62, wherein the second substrate is a silicon substrate.
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75. The method of claim 62, wherein the plurality or deflectable elements are formed by depositing a sacrificial layer on the first substrate, depositing one or more deflectable structural layers thereon, and releasing the micromirrors by removing the sacrificial layer.
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76. The method of claim 75, wherein the sacrificial layer comprises silicon.
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77. The method of claim 75, wherein the sacrificial silicon layer is removed with xenon difluoride.
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78. The method of claim 62, wherein the micromirrors are formed of a ceramic material.
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79. The method of claim 78, wherein the ceramic material is silicon dioxide or silicon nitride.
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80. The method of claim 62, wherein the plurality of circuitry resembles memories.
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81. The method of claim 80, wherein the memory array comprises SRAM circuits to drive the electrodes.
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82. The method of claim 80, wherein the memories comprises DRAM circuits to drive the electrodes.
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83. A method of modulating light, comprising:
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providing a spatial light modulator that comprises;
a substrate that is transmissive to visible light;
a silicon substrate having a plurality of electrodes and circuitry;
wherein the silicon substrate and the substrate that is transmissive to visible light are bonded together with a spacer therebetween forming a gap between the substrates; and
a plurality of deflectable elements encapsulated within the gap;
providing an incoming light beam that passes through the light transmissive substrate and that is reflected by the electrostatically deflectable elements;
applying a voltage bias between the deformable element and the electrode so as to deflect the deflectable element due to electrostatic attraction; and
deflecting the light beam back through the optically transmissive substrate. - View Dependent Claims (84, 85, 86, 87, 88)
a mirror plate having a reflective surface for reflecting light; and
a hinge to which the mirror plate is attached such that the mirror plate is operable to rotate.
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85. The method of claim 84, wherein the micromirrors are positioned on the substrate that is transmissive to visible light.
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86. The method of claim 84, wherein the micromirrors are positioned on the silicon substrate.
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87. The method of claim 83, wherein the silicon substrate is a VLSI-fabricated silicon substrate.
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88. The method of claim 83, wherein the circuitry is an addressing circuitry resembling a memory.
Specification