Patent US4696533A successfully refreshed from Google Patents.
US4696533A
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Spatial light modulator
Assignee: Massachusetts Institute of Technology
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Filing: 1981-01-12
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Granted: 1987-09-29
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Expires: 2001-01-12
Abstract
Abstract Spatial light modulators which use a substrate having a buried channel charge-coupled device (CCD) formed therein, wherein the amount of charge in the charge storage wells associated with the electrodes of the CCD is controlled by an electrically or optically addressed data signal. The level of charge in such charge storage wells controls the electric field beneath the electrodes so that the intensity of electromagnetic energy (e.g., light) directed through the CCD is spatially modulated by the charge levels in the charge storage wells in accordance with the Franz-Keldysh electroabsorption effect.
Inventors
- 👤 Robert H. Kingston
- 👤 Frederick J. Leonberger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:46
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/015; G02F1/025; G02F1/0126; G02F1/0155; G02F1/0157
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
118 words
An electro-optical system for use as a spatial light modulator comprising a substrate; a charge-coupled device formed in a layer at a selected surface of said substrate, said layer having a plurality of electrodes each having a charge storage well associated therewith; means for supplying input data to said charge-coupled device so that the charge levels in each of said charge storage wells represent the magnitude of said input data; said charge-coupled device being arranged so that an input electromagnetic wave can be directed through said electro-optical system to provide an output electromagnetic wave, the intensity of said output electromagnetic wave thereby being spatially modulated by the electric fields controlled by the charge levels in said storage wells.
Claim 2
Dependent Claim
118 words
An electro-optical system for use as a spatial light modulator comprising a substrate; a charge-coupled device formed in a layer at a selected surface of said substrate, said layer having a plurality of electrodes each having a charge storage well associated therewith; means for supplying input data to said charge-coupled device so that the charge levels in each of said charge storage wells represent the magnitude of said input data; said charge-coupled device being arranged so that an input electromagnetic wave can be directed through said electro-optical system to provide an output electromagnetic wave, the intensity of said output electromagnetic wave thereby being spatially modulated by the electric fields controlled by the charge levels in said storage wells.
Claim 3
Dependent Claim
43 words
An electro-optical system in accordance with claim 1 wherein said charge-coupled device is a buried channel charge-coupled device; and the wavelength of said input electromagnetic wave is selected to permit said buried channel charge-coupled device to selectively absorb said electromagnetic wave by electro-absorption.
Claim 4
Dependent Claim
16 words
An electro-optical device in accordance with claim 2 wherein said substrate is a semi-insulating semiconductor substrate
Claim 5
Dependent Claim
17 words
An electro-optical device in accordance with claim 3 or 3 wherein said layer is an n-type material.
Claim 6
Dependent Claim
34 words
An electro-optical device in accordance with claim 4 wherein said substrate comprises a gallium arsenide substrate and said n-type layer is a gallium arsenide layer having a preselected thickness and a preselected doping density.
Claim 7
Dependent Claim
24 words
An electro-optical device in accordance with claim 5 wherein said preselected thickness lies within a range from about 1 μm to about 5 μm.
Claim 8
Dependent Claim
16 words
An electro-optical device in accordance with claim 6 wherein said preselected thickness is about 4 μm.
Claim 9
Dependent Claim
29 words
An electro-optical device in accordance with claim 5 wherein said doping density lies within a range from about 10 15 /cm 3 to about 10 16 /cm 3 .
Claim 10
Dependent Claim
19 words
An electro-optical device in accordance with claim 8 wherein said doping density is about 5×10 15 cm 3 .
Claim 11
Dependent Claim
15 words
An electro-optical device in accordance with claim 3 wherein said substrate is a p-type substrate.
Claim 12
Dependent Claim
33 words
An electro-optical device in accordance with claim 2 wherein said substrate comprises a substrate of mercury-cadmium-telluride and said layer is an n-type mercury-cadmium-telluride layer having a preselected thickness and a preselected doping density.
Claim 13
Dependent Claim
35 words
An electro-optical device in accordance with claim 2 wherein said substrate comprises a substrate of indium antimonide and said layer is an n-type indium antimonide layer having a preselected thickness and a preselected doping density.
Claim 14
Dependent Claim
27 words
An electro-optical device in accordance with claim 2 wherein said input electromagnetic wave is directed onto the plane of said electrodes in a direction substantially perpendicular thereto.
Claim 15
Dependent Claim
23 words
An electro-optical device in accordance with claim 13 wherein said buried channel charge-coupled device is formed as a one-dimensional row of said electrodes.
Claim 16
Dependent Claim
30 words
An electro-optical device in accordance with claim 13 wherein said input electromagnetic wave is transmitted through said substrate to provide said output electromagnetic wave at other than said selected surface.
Claim 17
Dependent Claim
62 words
An electro-optical device in accordance with claim 2 wherein said input data supplying means comprises write-in input circuit means responsive to an electrical input signal applied thereto, which input signal contains said input data, for transferring said electrical input data to said electrodes to provide the charge levels in each said charge storage wells which represent the magnitude of said input data.
Claim 18
Dependent Claim
19 words
An electro-optical device in accordance with claim 2 wherein said absorption is in accordance with the Franz-Keldysh electroabsorption effect.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-09-28 | 1991-03-30 | 1991-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-09-28 | 1995-03-30 | 1995-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-09-28 | 1999-03-30 | 1999-09-29 | $7700.00 | Window Closed / Lapsed |