# US 2001/0017841 A1 · Optical recording medium, and method of manufacturing same

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- Number: US 2001/0017841 A1
- Document ID: US20010017841A1
- Status: Published application
- Kind: A1
- Application number: 09/841,986
- Filed: 2001-04-25
- Published: 2001-08-30
- Earliest claimed: 1998-02-27
- Assignees: Sony Corporation
- Inventors: Shin Masuhara
- Web page: https://patentgrep.com/patent/US20010017841A1

## CPC

- G11B 11/10582: {Record carriers characterised by the selection of the material or by the structure or form}
- 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 7/261: {Preparing a master, e.g. exposing photoresist, electroforming}
- G11B 7/263: {Preparing and using a stamper, e.g. pressing or injection molding substrates (production of optical record carriers, e.g. optical discs B29D17/005)}
- G11B 7/24085: Pits
- 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

There are provided an optical recording medium and a method of manufacturing the optical recording medium. The optical recording medium has a pattern of microscopic depressions and projections molded thereon with a high fidelity of replication. The method of manufacturing the optical recording medium comprises the steps of forming a photoresist layer on a substrate; exposing a predetermined area of the photoresist layer formed on the substrate to form a plurality of trains of depressions in the photoresist layer; removing the photoresist layer between the adjoining depression trains to form a master; plating the master with a metal; separating the metal coating to form a master stamper; replicating the master stamper repeatedly an odd number of times to form a mother stamper; replicating the mother stamper to form a resin substrate; and forming at least a light-transparent layer on a surface of the resin substrate on which the mother stamper is replicated. The method can mold a pattern of microscopic depressions and projections with a high accuracy.

## Claims

### Claim 1

An optical recording medium comprising a substrate and at least a light-transparent layer provided on the substrate, and with respect to which a signal is written and/or read by a light of a predetermined wavelength irradiated from above and through the light-transparent layer;
the substrate having formed thereon projections being convex as viewed from the light-transparent layer and depressions positioned in line with the projections and deep from a same height as the main surfaces of the projections.

### Claim 2 (depends on 1)

The optical recording medium according to claim 1, further comprising:
a reflective layer formed on the substrate; and
a recording layer formed on the reflective layer;
the recording layer on the projections being used as a recordable area.

### Claim 3 (depends on 2)

The optical recording medium according to claim 2, wherein the recording layer is any one of a phase-change recording layer, magneto-optical recording layer and organic-dye type recording layer.

### Claim 4

A method of manufacturing an optical recording medium, comprising the steps of:
forming a photoresist layer on a substrate;
exposing a predetermined area of the photoresist layer formed on the substrate to form a plurality of trains of depressions in the photoresist layer;
removing the photoresist layer between the adjoining depression trains to form a master;
plating the master with a metal;
separating the metal coating to form a master stamper;
replicating the master stamper repeatedly an odd number of times to form a mother stamper;
replicating the mother stamper to form a resin substrate; and
forming at least a light-transparent layer on a surface of the resin substrate on which the mother stamper has been replicated.

### Claim 5 (depends on 4)

The method according to claim 4, further comprising the step of:
forming grooves in line with the train of depressions.

### Claim 6 (depends on 5)

The method according to claim 5, wherein the substrate is exposed at the bottoms of the grooves and depressions, respectively.

### Claim 7 (depends on 4)

The method according to claim 4, wherein the photoresist layer is a positive-type one.

### Claim 8 (depends on 7)

The method according to claim 7, further comprising the steps of:
forming the depressions by exposing the photoresist layer to a first light; and
removing the photoresist layer between the trains of depressions by exposing the photoresist layer to a second light.

### Claim 9 (depends on 8)

The method according to claim 8, wherein the first light and second light are obtained by splitting a light from a single source and irradiated to the photoresist layer through a same objective lens.