# US 5,700,540 A · Optical recording medium

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- Number: US 5,700,540 A
- Document ID: US5700540A
- Status: Granted
- Kind: A
- Application number: 08/686,093
- Filed: 1996-07-24
- Granted: 1997-12-23
- Earliest claimed: 1996-07-24
- Assignees: Eastman Kodak Company
- Inventors: Giuseppe Farruggia; Tukaram K. Hatwar; Michael P. Cunningham
- Web page: https://patentgrep.com/patent/US5700540A

## CPC

- G11B 7/252: of layers other than 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 7/2433: Metals or elements of Groups 13, 14, 15 or 16 of the Periodic Table, e.g. B, Si, Ge, As, Sb, Bi, Se or Te
- G11B 11/10591: {for improving write-in properties, e.g. Curie-point temperature}
- G11B 11/10593: {for improving read-out properties, e.g. polarisation of light}
- G11B 7/2534: polycarbonates [PC]
- G11B 7/2542: consisting essentially of organic resins
- G11B 7/26: Apparatus or processes specially adapted for the manufacture of record carriers
- G11B 2007/24306: {transition metal elements of groups 3-10}
- G11B 2007/25708: {containing group 13 elements (B, Al, Ga)}
- G11B 2007/2571: {containing group 14 elements except carbon (Si, Ge, Sn, Pb)}
- G11B 2007/25715: {containing oxygen}
- Y10S 428/913: Material designed to be responsive to temperature, light, moisture
- Y10S 430/146: Laser beam
- Y10T 428/21: Circular sheet or circular blank
- 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 recording medium comprising a substrate with grooves, a surface smoothing layer less than 1 .mu.m thickness deposited on the grooved substrate, and a recording layer. The medium reduces noise and improves sensitivity relative to media which do not have a surface smoothing layer.

## Claims

### Claim 1

An optical recording medium comprising:
a) a substrate with grooves;
b) a surface smoothing layer less than 1 .mu.m thick deposited on the grooved substrate wherein the said surface smoothing layer includes monomers selected from the group consisting of: ##STR3## , and c) a recording layer.

### Claim 2 (depends on 1)

The optical recording medium of claim 1 wherein the said recording layer is a magneto-optical structure.

### Claim 3 (depends on 1)

The optical recording medium of claim 1 wherein the said recording layer is a Co/Pt multilayer film consisting of alternating layers of Co/Pt.

### Claim 4 (depends on 3)

The optical recording medium of claim 3 wherein a seed layer is deposited onto the said smoothing layer.

### Claim 5 (depends on 3)

The optical recording medium of claim 3 wherein the said multilayer film contains 2-25 bilayers of Co and Pt, the thickness of each of Co and Pt layer being uniform and between 0.2 to 0.8 nm and 0.4 to 1.8 nm respectively.

### Claim 6 (depends on 1)

The optical recording medium of claim 1 wherein a seed layer is deposited onto the said smoothing layer.

### Claim 7 (depends on 6)

The optical recording medium of claim 6 wherein said smoothing layer has a thickness of 20-500 nm and is selected to improve the noise level and performance of the optical disk.

### Claim 8 (depends on 7)

The optical recording medium of claim 7 further providing an UV curable lacquer overcoat on the recording layer.

### Claim 9 (depends on 1)

The optical recording medium of claim 1 wherein said smoothing layer has a thickness of 20-500 nm and is selected to improve the noise level and performance of the optical-disk.

### Claim 10 (depends on 1)

The optical recording medium of claim 1 wherein the said surface smoothing layer maintains conformality greater than 20% to the substrate grooves.

### Claim 11 (depends on 1)

The optical recording medium of claim 1 wherein the said surface smoothing layer maintains conformality greater than 20% to the substrate grooves.

### Claim 12 (depends on 1)

The optical recording medium of claim 1 further providing an UV curable lacquer overcoat on the recording layer.