Patent EP0173523A2 successfully refreshed from Google Patents.
EP0173523A2
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Optical memory
Assignee: Toshiba Corp
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Filing: 1985-08-16
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Granted: —
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Expires: 2005-08-16
Abstract
Abstract 57' A memory device for optically storing and retrieving information comprising a substrate and a recording layer supported on the substrate. The recording layer comprises a chemically stable dielectric material and a semiconductor which has an optical property that changes reversibly as a function of the intensity of a laser beam applied through the substrate. A multi- layered optical disc memory comprising a substrate, a recording layer formed on the substrate and a metallic layer formed on the recording layer, and a method of optically storing and retrieving information by using the above-described optical disc memory are also disclosed.
Inventors
- 👤 Takashi Takaoka
- 👤 Kiyoshi C/O Patent Division Tsuboi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 21:50
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/241; G11B7/252; G11B7/257; G11B7/242; G11B7/243; G11B7/2433; G11B7/004; G11B7/0055; G11B7/00557; G11B7/26; G11B2007/24302; G11B2007/2431; G11B2007/24312; G11B2007/24314; G11B2007/24316; G11B2007/25705; G11B2007/25706; G11B2007/25708; G11B2007/2571; G11B2007/25715; Y; Y10; Y10S; Y10S430/00; Y10S430/146
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
44 words
An optical memory device comprising: (a) a substrate; and - (b) a recording layer supported on said substrate, said recording layer comprising a chemically stable dielectric material and a semiconductor material capable of undergoing a change in optical reflectivity when exposed to electromagnetic radiation.
Claim 2
Dependent Claim
44 words
An optical memory device comprising: (a) a substrate; and - (b) a recording layer supported on said substrate, said recording layer comprising a chemically stable dielectric material and a semiconductor material capable of undergoing a change in optical reflectivity when exposed to electromagnetic radiation.
Claim 3
Dependent Claim
25 words
An optical memory device according to claim 1, wherein the fractional volume factor of said semiconductor material in said layer is more than about 40%.
Claim 4
Dependent Claim
31 words
An optical memory device according to any preceding claim, wherein the ratio of the optical thickness of said recording layer, to the wavelength of an applied light beam is about 1:2.
Claim 5
Dependent Claim
16 words
An optical memory device according to any preceding claim, wherein said substrate comprises a transparent disc.
Claim 6
Dependent Claim
18 words
An optical memory device according to claim 4, wherein said transparent disc has grooves suitable for optical tracking.
Claim 7
Dependent Claim
30 words
An optical memory device according to any preceding claim, wherein said semiconductor material is one which undergoes a phase transition between amorphous structure and crystalline structure when exposed to light.
Claim 8
Dependent Claim
18 words
An optical memory device according to any preceding claim, wherein said electromagnetic radiation comprises a laser beam 1.
Claim 9
Dependent Claim
30 words
An optical memory device according to claim 7 when appendent to claim 6, wherein said phase transition is dependent on the exposure time and power density of said laser beam.
Claim 10
Dependent Claim
33 words
An optical memory device acccording to any preceding claim, further comprising a metallic layer formed on said recording layer, such that light passing through said recording layer is reflected by said metallic layer.
Claim 11
Dependent Claim
22 words
An optical memory device according to claim 9, wherein said metallic layer comprises at least one of Au, Ag, Cu or A1.
Claim 12
Dependent Claim
22 words
An optical memory device according to any preceding claim, wherein said semiconductor material comprises at least one of Ge, Te or InSb.
Claim 13
Dependent Claim
50 words
An optical memory device according to any preceding claim, wherein said dielectric material comprises at least one of B 2 0 3 , Sb203, Bi203, PbO, Si0 2 , Ta 2 0 5 , BiF 3 , LiF, PbF 2 , MgF 2 , BaF 2 or CaF 2 .
Claim 14
Dependent Claim
46 words
An optical memory device according to any preceding claim wherein said recording layer is produced by a process which includes co-evaporating or co-sputtering said semiconductor material and said dielectric material onto said substrate in a high vacuum or at low pressure to form said recording layer.
Claim 15
Dependent Claim
18 words
An optical memory device according to claim 9 further comprising a protective layer provided on said metallic layer.
Claim 16
Dependent Claim
26 words
An optical memory device according to any preceding claim further comprising a semitransparent metallic layer formed on said substrate, between said substrate and said recording layer.
Claim 17
Dependent Claim
34 words
An optical memory device according to claim 15 wherein said semitransparent metallic layer comprises at least one of Au, Ag, Cu and Al and has a layer thickness of about 0.03 µm or less.
Claim 18
Independent Claim
70 words
A method of storing information comprising the steps of: (a) providing a recording layer comprising a chemically stable dielectric material and a semiconductor material capable of undergoing a change in optical reflectivity when exposed to light; and (b) applying a light beam to selected portions of said recording layer to cause a first structural change in said semiconductor material in said portion, whereby optical reflectivity of said portions is altered.
Claim 19
Independent Claim
70 words
A method of storing information comprising the steps of: (a) providing a recording layer comprising a chemically stable dielectric material and a semiconductor material capable of undergoing a change in optical reflectivity when exposed to light; and (b) applying a light beam to selected portions of said recording layer to cause a first structural change in said semiconductor material in said portion, whereby optical reflectivity of said portions is altered.
Claim 20
Dependent Claim
27 words
A method of retrieving information stored in accordance with the method of claim 17, comprising optically detecting said structural change in said portions of said recording layer.
Claim 21
Dependent Claim
16 words
A method according to claim 17, wherein said recording layer is formed on a transparent disc.
Claim 22
Dependent Claim
43 words
A method according to claim 17, wherein the optical reflectivity of said recording layer is changed by applying a laser beam at a power density which is sufficient to cause said structural change but insufficient to form a pit on said recording layer.
Claim 23
Dependent Claim
31 words
A method according to claim 17, further comprising after step (b) the step of reapplying a light beam to said portions to cause a second structural change in said semiconductor material.
Claim 24
Independent Claim
65 words
A method for producing an optical memory element, comprising the step of co-evaporating or co-sputtering a semiconductor material and a dielectric material onto a substrate in a high vacuum or a low pressure to form on said substrate a recording layer comprising said semiconductor material and said dielectric material, said semiconductor material being capable of undergoing a change in optical reflectivity when exposed to light.
Claim 25
Independent Claim
65 words
A method for producing an optical memory element, comprising the step of co-evaporating or co-sputtering a semiconductor material and a dielectric material onto a substrate in a high vacuum or a low pressure to form on said substrate a recording layer comprising said semiconductor material and said dielectric material, said semiconductor material being capable of undergoing a change in optical reflectivity when exposed to light.
References Cited (Backward Citations)
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