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US 4,227,201 AGranted
CCD Readout structure for display applications
AssigneeHughes Aircraft Company
InventorsJan Grinberg, Michael Waldner, Joe A. Jenney
Life of this patent
Estimating the term…
Abstract
A liquid crystal light valve which uses the transfer of charge carriers representing a plurality of signals from a CCD array to a liquid crystal light modulated display medium. The signal charge is extracted from the back side of the CCD by driving the CCD clock voltages to zero and allowing the charge to diffuse to the back side where it is collected in a charge depleted region formed by a reverse biased diode and injected into the interface layers of a liquid crystal display medium.
Claims11
A liquid crystal light valve activated by a charge-coupled device (CCD) comprising:
- (a) a semiconductor substrate characterized by first and second major opposite surfaces;
- (b) a CCD arrangement formed on said first major substrate surface and including a set of CCD electrodes for storage and transfer of charge carriers in charge depletion buckets adjacent to said set of CCD electrodes;
- (c) a liquid crystal layer adjacent to said second major substrate surface;
- (d) means for establishing within said substrate an electric field substantially below avalanche breakdown wherein the value of said field is selected to form a depletion region and an undepleted region between said first and second major substrate surfaces, said undepleted region separating said charge depletion buckets from said depletion regions;
- and
- (e) means for biasing said CCD electrodes so that said charge carriers are transferred from adjacent to said CCD electrodes through said undepleted region to said depletion region where they are then electric-field guided without avalanching through said depletion region to said second major substrate surface without substantial lateral spreading in order to activate said liquid crystal layer.
3 more elements
A liquid crystal light valve activated by a charge-coupled device (CCD) comprising:
- (a) a semiconductor substrate characterized by first and second major opposite surfaces;
- (b) a CCD structure formed adjacent to said first major substrate surface including a set of CCD electrodes and an insulating layer adjacent to said first surface for the insulation of said set of CCD electrodes;
- (c) a semiconductor interface layer between said insulating layer and said first major substrate surface for storage and transfer of said charge carriers in charge depletion buckets adjacent to said CCD electrodes;
- (d) a liquid crystal layer adjacent to said second major substrate surface;
- and
- (e) means for establishing an electric field substantially below avalanche breakdown in said substrate transverse to said major surfaces wherein the value of said field is selected to form a charge depletion region which extends between said major surfaces of said substrate and an undepleted region within said semiconductor interface layer, said undepleted region separating said charge depletion buckets from said depletion region within said substrate so that, when proper bias conditions are applied on said CCD electrodes, said charge carriers adjacent to said CCD electrodes diffuse through said interface layer to said charge depletion region where they are then electric-field guided without avalanching through said substrate without substantial lateral spreading in order to activate said liquid crystal layer.
3 more elements
A liquid crystal light valve activated by a charge-coupled device (CCD) comprising:
- (a) a semiconductor substrate characterized by first and second major opposite surfaces;
- (b) a CCD structure formed adjacent to said first major substrate surface including a set of CCD electrodes and an insulating layer adjacent to said first surface for the insulation of said set of CCD electrodes;
- (c) a semiconductor interface layer between said insulating layer and said first major substrate surface for storage and transfer of said charge carriers in charge depletion buckets adjacent to said CCD electrodes;
- (d) a liquid crystal layer adjacent to said second major substrate surface;
- (e) a rectifying junction formed in a portion of said substrate;
- (f) means for reverse-biasing said junction to establish an electric field substantially below avalanche breakdown wherein the value of said field, the thicknesses of said semiconductor interface layer and said semiconductor substrate, and the resistivities of said semiconductor interfere layer and said semiconductor substrate are selected to form a depletion region between said first and second major substrate surfaces and an undepleted region within said semiconductor interface layer, said undepleted region separating said charge depletion buckets adjacent to said CCD electrodes from said depletion region within said substrate;
- and
- (g) means for biasing said CCD electrodes so that said charge carriers diffuse from said interface layer through said undepleted region to said substrate depletion region where they are then electric-field guided without avalanching through said depletion region to said second major substrate surface without substantial lateral spreading in order to activate said liquid crystal layer.
5 more elements
Dependencies are inferred from the claim text.