Patent EP0235748A2 successfully refreshed from Google Patents.
EP0235748A2
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Liquid crystal disc memory
Assignee: Semiconductor Energy Laboratory Co Ltd
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Filing: 1987-02-26
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Granted: —
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Expires: 2007-02-26
Abstract
Abstract An improved optical memory disc (10) is disclosed which has a liquid crystal layer (6) on which information is written by applying electric field. The liquid crystal layer is sectioned into a plurality of concentric tracks by concentric grooves. When information is written or read, an auto-tracking method can implemented by aid of the grooves.
Inventors
- 👤 Shunpei Yamazaki
- 👤 Takeshi Mizunuma
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 22:02
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/241; G11B13/00
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
82 words
A liquid crystal optical disc memory comprising: a transparent substrate; an opposed substrate; a liquid crystal layer disposed between said substrates and capable of changing locally its state with distinct optical characteristics in response to change of the physical condition to which the liquid crystal is subjected; a plurality of circular grooves formed on one of said substrates and extending parallel in the circumferential direction; and means for keeping said liquid crystal layer from changing its state in absence of external operation.
Claim 2
Dependent Claim
82 words
A liquid crystal optical disc memory comprising: a transparent substrate; an opposed substrate; a liquid crystal layer disposed between said substrates and capable of changing locally its state with distinct optical characteristics in response to change of the physical condition to which the liquid crystal is subjected; a plurality of circular grooves formed on one of said substrates and extending parallel in the circumferential direction; and means for keeping said liquid crystal layer from changing its state in absence of external operation.
Claim 3
Dependent Claim
13 words
A memory of claim 1 wherein said grooves are formed on concentric circles.
Claim 4
Dependent Claim
13 words
A memory of claim 1 wherein said grooves interconnect to make a spiral.
Claim 5
Dependent Claim
28 words
A memory of claim 1 wherein the circular regions between adjacent said grooves constitute tracks for writing on which information is written in terms of said optical characteristics.
Claim 6
Dependent Claim
23 words
A memory of claim 1 wherein said grooves constitute tracks for writing on which information is written in terms of said optical characteristics.
Claim 7
Dependent Claim
14 words
A memory of claim 1 wherein said physical condition is existence of electric field.
Claim 8
Dependent Claim
24 words
A memory of claim 6 said means is a ferroelectric layer adjacent to said liquid crystal layer to be subjected to said electric field.
Claim 9
Dependent Claim
44 words
A memory of claim 6 wherein said means comprises a charge storage region and an insulator which allows carriers to pass therethrough into said storage region only when external electric field is applied and blocks escape of the carriers stored in said storage region.
Claim 10
Dependent Claim
23 words
A memory of claim 8 wherein said storage region is made of silicon nitride which comes abundant in dangling bonds by heavy doping.
Claim 11
Dependent Claim
13 words
A memory of claim 8 wherein said storage region is made of semiconductor.
Claim 12
Dependent Claim
14 words
A memory of claim 10 wherein said semiconductor layer is heavily doped with impurity.
Claim 13
Dependent Claim
16 words
A memory of claim 10 wherein said storage region is provided in the form of clusters.
Claim 14
Dependent Claim
15 words
A memory of claim 4 further comprising a pair of electrodes provided on said substrates.
Claim 15
Dependent Claim
34 words
A memory of claim 4 wherein said liquid crystal layer is made of a nematic liquid crystal and opposed inside of the substrates contiguous to said liquid crystal layer are oriented in perpendicular directions.
Claim 16
Dependent Claim
19 words
A memory of claim 4 wherein said liquid crystal layer is made of a tilted chiral smectic liquid crystal.
Claim 17
Dependent Claim
24 words
A memory of claim 13 integrated by a jig having inner terminals in contact with said electrodes and external pads connected with said terminals.
Claim 18
Dependent Claim
13 words
A memory of claim 1 wherein said grooves function also as tracking-guide means.
References Cited (Backward Citations)
No citation records indexed.
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