# US 5,708,653 A · Single-substrate multi-layer optical disk for read-only storage and phase change rewritable storage

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- Number: US 5,708,653 A
- Document ID: US5708653A
- Status: Granted
- Kind: A
- Application number: 08/732,578
- Filed: 1996-10-15
- Granted: 1998-01-13
- Earliest claimed: 1995-10-13
- Assignees: NEC Corporation
- Inventors: Mitsuya Okada; Syuichi Ohkubo
- Web page: https://patentgrep.com/patent/US5708653A

## CPC

- G11B 7/2578: consisting essentially of inorganic materials
- 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 7/24038: Multiple laminated recording layers
- G11B 7/258: of reflective layers
- G11B 7/0052: {involving reflectivity, absorption or colour changes}
- G11B 7/0079: {Zoned data area, e.g. having different data structures or formats for the user data within data layer, Zone Constant Linear Velocity [ZCLV], Zone Constant Angular Velocity [ZCAV], carriers with RAM and ROM areas}
- G11B 7/2531: comprising glass
- G11B 7/2534: polycarbonates [PC]
- G11B 7/2542: consisting essentially of organic resins
- G11B 7/256: of layers improving adhesion between layers
- G11B 7/2585: based on aluminium
- 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 2007/2571: {containing group 14 elements except carbon (Si, Ge, Sn, Pb)}
- G11B 2007/25715: {containing oxygen}
- G11B 2007/25716: {containing sulfur}
- G11B 2220/216: Rewritable discs
- G11B 2220/237: having exactly two recording layers
- 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)

## Abstract

An optical disk includes a transparent rigid substrate, a phase change rewritable optical recording medium formed on the transparent rigid substrate, a transparent spacer formed on the phase change rewritable optical recording medium and having a grooved surface for storing information, and a reflecting layer formed on the grooved surface of the transparent spacer. The grooved surface of the transparent spacer and the reflecting layer form a read-only recording medium.

## Claims

### Claim 1

An optical disk comprising:
a transparent rigid substrate;
a phase change rewritable optical recording medium formed on said transparent rigid substrate;
a transparent spacer formed on said phase change rewritable optical recording medium and having a grooved surface for storing information; and
a reflecting layer formed on the grooved surface of said transparent spacer,
the grooved surface of said transparent spacer and said reflecting layer forming a read-only recording medium.

### Claim 2 (depends on 1)

The optical disk as set forth in claim 1, wherein said phase change rewritable optical recording medium comprises:
a transparent lower passivation layer formed on said transparent rigid substrate;
a phase change recording layer formed on said transparent lower passivation layer;
a transparent upper passivation layer formed on said phase change recording layer;
a transparent reflecting layer formed on said transparent upper passivation layer; and
a transparent interference layer formed on said transparent reflecting layer.

### Claim 3 (depends on 2)

The optical disk as set forth in claim 2, wherein said phase change recording layer is made of Ge, Sb and Te.

### Claim 4 (depends on 2)

The optical disk as set forth in claim 2, wherein each of said transparent lower passivation layer, said transparent upper passivation layer and said transparent interference layer is made of ZnS and SiO.sub.2.

### Claim 5 (depends on 2)

The optical disk as set forth in claim 2, wherein said transparent reflecting layer is made of Si.

### Claim 6 (depends on 2)

The optical disk as set forth in claim 2, wherein said transparent reflecting layer is made of Ge.

### Claim 7 (depends on 2)

The optical disk as set forth in claim 2, wherein said transparent reflecting layer is made of SiO.

### Claim 8 (depends on 2)

The optical disk as set forth in claim 2, wherein said transparent reflecting layer is made of SiN.

### Claim 9 (depends on 2)

The optical disk as set forth in claim 2, wherein said transparent reflecting layer is made of GeO.

### Claim 10 (depends on 2)

The optical disk as set forth in claim 2, wherein said transparent reflecting layer is made of GeN.

### Claim 11 (depends on 2)

The optical disk as set forth in claim 2, wherein transmission of laser light for said phase change rewritable optical recording medium is approximately 30 to 60 percent.

### Claim 12 (depends on 1)

The optical disk as set forth in claim 1, wherein said transparent spacer is made of lightsetting resin.

### Claim 13 (depends on 12)

The optical disk as set forth in claim 12, wherein said transparent spacer is approximately 5 to 50 .mu.m.

### Claim 14 (depends on 1)

The optical disk as set forth in claim 1, wherein said reflecting layer is made of metal.

### Claim 15

An optical disk comprising first and second disk portions adhered by an adhesive layer,
each of said first and second disk portions comprising:
a transparent rigid substrate;
a phase change rewritable optical recording medium formed on said transparent rigid substrate;
a transparent spacer formed on said phase change rewritable optical recording medium and having a grooved surface for storing information;
a reflecting layer formed on the grooved surface of said transparent spacer, the grooved surface of said transparent spacer and said reflecting layer forming a read-only recording medium; and
an overcoat layer formed on said reflecting layer,
said overcoat layer of said first disk portion and said overcoat layer of said second portion being adhered by said adhesive layer.

### Claim 16 (depends on 15)

The optical disk as set forth in claim 15, wherein said phase change rewritable optical recording medium comprises:
a transparent lower passivation layer formed on said transparent rigid substrate;
a phase change recording layer formed on said transparent lower passivation layer;
a transparent upper passivation layer formed on said phase change recording layer;
a transparent reflecting layer formed on said transparent upper passivation layer; and
a transparent interference layer formed on said transparent reflecting layer.

### Claim 17 (depends on 2)

The optical disk as set forth in claim 2, wherein said phase change recording layer is made of Ge, Sb and Te.

### Claim 18 (depends on 16)

The optical disk as set forth in claim 16, wherein each of said transparent lower passivation layer, said transparent upper passivation layer and said transparent interference layer is made of ZnS and SiO.sub.2.

### Claim 19 (depends on 16)

The optical disk as set forth in claim 16, wherein said transparent reflecting layer is made of Si.

### Claim 20 (depends on 16)

The optical disk as set forth in claim 16, wherein said transparent reflecting layer is made of Ge.

### Claim 21 (depends on 16)

The optical disk as set forth in claim 16, wherein said transparent reflecting layer is made of SiO.

### Claim 22 (depends on 16)

The optical disk as set forth in claim 16, wherein said transparent reflecting layer is made of SiN.

### Claim 23 (depends on 16)

The optical disk as set forth in claim 16, wherein said transparent reflecting layer is made of GeO.

### Claim 24 (depends on 16)

The optical disk as set forth in claim 16, wherein said transparent reflecting layer is made of GeN.

### Claim 25 (depends on 16)

The optical disk as set forth in claim 16, wherein transmission of laser light for said phase change rewritable optical recording medium is approximately 30 to 60 percent.

### Claim 26 (depends on 15)

The optical disk as set forth in claim 15, wherein said transparent spacer is made of lightsetting resin.

### Claim 27 (depends on 26)

The optical disk as set forth in claim 26, wherein said transparent spacer is approximately 5 to 50 .mu.m.

### Claim 28 (depends on 15)

The optical disk as set forth in claim 15, wherein said reflecting layer is made of metal.

### Claim 29

A method for controlling an optical disk including a transparent rigid substrate, a phase change rewritable optical recording medium formed on said transparent rigid substrate, a transparent spacer formed on said phase change rewritable optical recording medium and having a grooved surface for storing information, and a reflecting layer formed on the grooved surface of said transparent spacer, the grooved surface of said transparent spacer and said reflecting layer forming a read-only recording medium, comprising:
means for performing a writing, erasing and reproducing operation upon said phase change rewritable optical medium by focusing a laser beam at said phase change rewritable optical medium; and
means for performing a reproducing operation upon said read-only medium by focusing a laser beam at said read-only medium.