# US 5,346,740 A · Optical information recording medium

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,346,740 A
- Document ID: US5346740A
- Status: Granted
- Kind: A
- Application number: 07/765,514
- Filed: 1991-09-25
- Granted: 1994-09-13
- Earliest claimed: 1990-09-25
- Assignees: Matsushita Electric Industrial Co., Ltd.
- Inventors: Eiji Ohno; Noboru Yamada; Kenichi Nagata; Kenichi Nishiuchi; Nobuo Akahira
- Web page: https://patentgrep.com/patent/US5346740A

## CPC

- G11B 7/257: of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers
- G11B 7/24: Record carriers characterised by shape, structure or physical properties, or by the selection of the material (characterised by the arrangement of information on the carrier G11B7/007)
- G11B 7/243: comprising inorganic materials only, e.g. ablative layers
- G11B 7/252: of layers other than recording layers
- G11B 7/2531: comprising glass
- G11B 7/2533: comprising resins
- G11B 7/2595: based on gold
- G11B 2007/24308: {transition metal elements of group 11 (Cu, Ag, Au)}
- G11B 2007/2431: {group 13 elements (B, Al, Ga, In)}
- G11B 2007/24312: {group 14 elements (e.g. Si, Ge, Sn)}
- G11B 2007/24314: {group 15 elements (e.g. Sb, Bi)}
- G11B 2007/24316: {group 16 elements (i.e. chalcogenides, Se, Te)}
- G11B 2007/25706: {containing transition metal elements (Zn, Fe, Co, Ni, Pt)}
- G11B 2007/25708: {containing group 13 elements (B, Al, Ga)}
- G11B 2007/2571: {containing group 14 elements except carbon (Si, Ge, Sn, Pb)}
- G11B 2007/25713: {containing nitrogen}
- G11B 2007/25715: {containing oxygen}
- G11B 2007/25716: {containing sulfur}
- Y10S 428/913: Material designed to be responsive to temperature, light, moisture
- Y10S 430/146: Laser beam
- Y10T 428/31504: Composite [nonstructural laminate]
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

An optical information recording medium comprising a substrate, and a dielectric layer, a recording layer, a dielectric layer and a reflective layer which are laminated on the substrate in this order or a reflective layer, a dielectric layer, a recording layer and a dielectric layer which are laminated on the substrate in this order, wherein a state of the recording layer is reversibly changed between optically recognizable states by irradiation of, for example, a laser beam and the recording layer has a thickness of from 1 nm to 10 nm, which recording medium has improved recording sensitivity.

## Claims

### Claim 1

An optical information recording medium comprising a substrate, and a dielectric layer, a recording layer, a dielectric layer and a reflective layer which are laminated on said substrate in this order or a reflective layer, a dielectric layer, a recording layer and a dielectric layer which are laminated on said substrate in this order, wherein the state of said recording layer is reversibly changed between optically recognizable states by irradiation and said recording layer has a thickness of from 1 nm to 10 nm.

### Claim 2 (depends on 1)

The optical information recording medium according to claim 1, wherein the thickness of said recording layer is from 3 nm to 8 nm.

### Claim 3 (depends on 1)

The optical information recording medium according to claim 1, wherein the thickness of said recording layer is about 5 nm.

### Claim 4 (depends on 1)

The optical information recording medium according to claim 1, wherein said recording layer comprises a phase-change material which is reversibly converted between a crystalline state and an amorphous state.

### Claim 5 (depends on 1)

The optical information recording medium according to claim 1, wherein said recording layer comprises at least one alloy selected from the group consisting of GeSeTe, InSbTe, GaSb, InGaSb, GeSnTe and AgSbTe.

### Claim 6 (depends on 5)

The optical information recording medium according to claim 5, wherein said recording layer comprises an alloy having a composition of a stoichiometric compound.

### Claim 7 (depends on 1)

The optical information recording medium according to claim 1, wherein said recording layer comprises an alloy which comprises M, Te and Ge and has a composition of the formula: M.sub.x Ge.sub.y Te.sub.z wherein 25.ltoreq.x.ltoreq.60, 0.ltoreq.y.ltoreq.25 and 37.5.ltoreq.z.ltoreq.60, and wherein M represents Sn or Pb.

### Claim 8 (depends on 7)

The optical information recording medium according to claim 7, wherein said alloy is M.sub.50-a Ge.sub.a Te.sub.50 wherein 0.ltoreq.a.ltoreq.25.

### Claim 9 (depends on 1)

The optical information recording medium according to claim 1, wherein said recording layer comprises SnTe or PbTe.

### Claim 10 (depends on 1)

The optical information recording medium according to claim 1, wherein said recording layer comprises an alloy containing Sn, Sb and Te and having a composition in which the deviation of the content of each element is within .+-.5 atomic percentages from the stoichiometric composition SnSb.sub.2 Te.sub.4.

### Claim 11 (depends on 1)

The optical information recording medium according to claim 1, wherein said recording layer comprises an alloy containing Sn, Sb, Te and Ge in which the concentration of Ge is smaller than that of Sn.

### Claim 12 (depends on 11)

The optical information recording medium according to claim 11, wherein said recording layer comprises Sn.sub.1-b Ge.sub.b Sb.sub.2 Te.sub.4 wherein 0<b<0.5.

### Claim 13 (depends on 1)

The optical information recording medium according to claim 1, wherein said recording layer comprises an alloy containing Pb, Sb and Te and having a composition in which the deviation of the content of each element is within .+-.5 atomic percentages from the stoichiometric composition Pb.sub.2 Sb.sub.6 Te.sub.11.

### Claim 14 (depends on 1)

The optical information recording medium according to claim 1, wherein said recording layer comprises an alloy containing Pb, Pb, Te and Ge in which the concentration of Ge is smaller than that of Sb.

### Claim 15 (depends on 14)

The optical information recording medium according to claim 14, wherein said recording layer comprises Pb.sub.2 Sb.sub.6 Te.sub.11 wherein 0<c<1.