Patent US953222A successfully refreshed from Google Patents.
EP0740188A2
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A reflective spatial light modulator array
Assignee: International Business Machines Corp
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Filing: 1996-04-09
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Granted: —
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Expires: 2016-04-09
Abstract
Abstract A reflective spatial light modulator array is described incorporating liquid crystal devices, mirrors, a semiconductor substrate, electrical circuits, and a reflector/absorber layer for blocking light. The invention overcomes the problem of shielding light from semiconductor devices, high optical throughput and contrast, pixel storage capacitance to hold the voltage across the liquid crystal device and precise control of the liquid crystal device thickness without spacers obscuring the mirrors.
Inventors
- 👤 Evan George Colgan
- 👤 James Mickell Edwin Harper
- 👤 Frank Benjamin Kaufman
- 👤 Margaret Paggy Manni
- 👤 Robert Lee Melcher
- 👤 James Louis Speidell
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 15:08
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/136; G02F1/1362; G02F1/136277; G02F1/1333; G02F1/1335; G02F1/133553; G02F1/136209; G02F1/1339; G02F1/13394; G02F2203/00; G02F2203/12
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
104 words
A spatial light modulator array for modulating light to form an image comprising: a plurality of liquid crystal devices positioned over respective mirrors on a dielectric layer on a semiconductor substrate, a plurality of electrical circuits formed in said semiconductor substrate coupled to said liquid crystal devices, respectively, for placing a voltage across its electrodes, and a reflector/absorber layer positioned and patterned with respect to said mirrors for shielding said plurality of electrical circuits from ambient light, said reflector/absorber layer having an edge overlapping an edge of said mirror to form an overlapping region to decrease ambient light from passing into said semiconductor substrate.
Claim 2
Dependent Claim
23 words
The spatial light modulator array of claim 1 wherein said reflector/absorber layer overlaps said edge of said mirror by at least 5.4 µm.
Claim 3
Dependent Claim
32 words
The spatial light modulator array of claim 1 wherein said mirrors are formed from a metal layer wherein said metal is selected from the group consisting of Ag, Al and alloys thereof.
Claim 4
Dependent Claim
47 words
The spatial light modulator array of claim 1 wherein said mirrors have a supporting layer having a substantially planar upper surface and not just on CMP surface said mirrors include a respective metal layer for reflecting light on said substantially planar upper surface of said supporting layer.
Claim 5
Dependent Claim
25 words
The spatial light modulator array of claim 4 wherein said supporting layer includes dielectric material and electrical vias for electrical connection to said metal layer.
Claim 6
Dependent Claim
30 words
The spatial light modulator array of claim 1 wherein said plurality of liquid crystal devices have a thickness determined by a dielectric layer having openings formed over said respective mirrors.
Claim 7
Dependent Claim
33 words
The spatial light modulator array of claim 6 wherein said dielectric layer includes material is selected from the group consisting of SiO 2 , SI 3 N 4 , diamond-like carbon, and polyamide.
Claim 8
Dependent Claim
36 words
The spatial light modulator array of claim 6 wherein said respective mirrors form the lower electrode of said plurality of liquid crystal devices and being electrically coupled to respective outputs of said plurality of electrical circuits.
Claim 9
Dependent Claim
31 words
The spatial light modulator array of claim 1 wherein said reflector/absorber layer is selected from the group consisting of Al, Cr-Cr x Oy, Ti and TiN and TiN x Cy where.
Claim 10
Dependent Claim
33 words
The spatial light modulator array of claim 1 wherein said reflector/absorber layer is electrically conductive and forms a blanket layer over said semiconductor substrate with openings therein for electrical vias to said mirrors.
Claim 11
Dependent Claim
19 words
The spatial light modulator array of claim 1 wherein said electrical circuits include complementary metal oxide silicon (CMOS) circuits.
Claim 12
Dependent Claim
25 words
The spatial light modulator array of claim 1 wherein each of said mirrors and said reflector/absorber layer forms a capacitor of at least 0.03 pf.
Claim 13
Dependent Claim
33 words
The spatial light modulator array of claim 1 wherein said liquid crystal devices are positioned in rows and columns on a pitch in each of two directions of about 17 microns or less.
Claim 14
Independent Claim
226 words
A method of forming a spatial light modulator array comprising the steps of: forming a plurality of electrical circuits in a semiconductor substrate positioned for interconnecting with subsequently formed liquid crystal devices, respectively, forming one or more layers of interconnections above said plurality of electrical circuits, forming a first dielectric layer over said electrical circuits and said layers of interconnections, planarizing said first dielectric layer to provide a substantally planar upper surface on said first dielectric layer, forming a reflector/absorber layer of condutive material, positioned and patterned with respect to subsequently formed liquid crystal devices for shielding said plurality of electrical circuits from ambient light, forming a second dielectric layer above said patterned reflector/absorber layer, forming studs through said second dielectric layer for electrical connection to subsequently formed mirrors, forming a plurality of mirrors over said dielectric layer and patterned to form the lower electrode of said plurality of liquid crystal devices, said mirrors overlapping said reflector/absorber layer to form a capacitor with respect to said overlapping mirror and to attenuate light traveling between said reflect/absorber and said mirror, forming a plurality of spacers positioned in between selected mirrors of said plurality of mirrors, applying a layer of liquid crystal material, orienting said layer of liquid crystal material, and forming a top electrode of said plurality of mirrors to form said plurality of liquid crystal devices.
References Cited (Backward Citations)
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