# US 4,477,328 A · Optically readable information disk and method of manufacturing same

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- Number: US 4,477,328 A
- Document ID: US4477328A
- Status: Granted
- Kind: A
- Application number: 06/354,830
- Filed: 1982-03-04
- Granted: 1984-10-16
- Earliest claimed: 1979-05-25
- Assignees: U.S. Philips Corporation
- Inventors: Egbert Broeksema; Arnoldus A. Smeets
- Web page: https://patentgrep.com/patent/US4477328A

## CPC

- G11B 7/26: Apparatus or processes specially adapted for the manufacture of record carriers
- B29C 35/0888: {using transparant moulds}
- B29C 43/021: {characterised by the shape of the surface}
- B29C 43/54: Compensating volume change, e.g. retraction
- B29C 45/263: {with mould wall parts provided with fine grooves or impressions, e.g. for record discs}
- B29D 17/005: {Producing optically read record carriers, e.g. optical discs}
- G03F 7/00: Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor (using photoresist structures for special production processes, see the relevant places, e.g. B44C, H10P76/00, H05K)
- B29C 2033/0005: {with transparent parts, e.g. permitting visual inspection of the interior of the cavity}
- B29C 2035/0827: {using UV radiation}
- B29C 2045/0075: {curing or polymerising by irradiation}
- B29K 2033/04: Polymers of esters
- B29L 2017/00: {Carriers for sound or information}
- 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)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00)
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES

## Abstract

The invention relates to an optically readable information disk, a method of manufacturing same, as well as a device for carrying out the method, in which the information disk which comprises an optically readable information track of information areas situated at a higher and a lower level, is manufactured entirely from a radiation-cured layer of a lacquer containing oligomeric acrylates or methacrylates which on an average per molecule comprise between one and four acrylate groups or methacrylate groups, has a viscosity of 1,000-15,000 cP and comprises a photoinitiator in a concentration of 0.1 to 0.5% by weight. Suitable lacquers comprise notably 1,1'-isopropylene-bis(p-phenoxyethylmethacrylate) or 1,1'-isopropylene-bis(p-phenoxyethylacrylate).

## Claims

### Claim 1

A self supported optically readable information disk of radiation cured synthetic resin having a thickness of about 0.5-3 mm the surface of which disk comprises an optically readable information track having a relief structure of information areas situated alternatively at a higher and lower level and which disk is formed by the irradiation of a radiation curable liquid composition having a viscosity of 1000-15,000 cP and comprising oligomeric acrylates or methacrylates which on the average per molecule comprise between one to four acrylate or methacrylate groups and a photoinitiator in a concentration of 0.1 to 0.5 percent by weight.

### Claim 2 (depends on 1)

An optically readable information disk as claimed in claim 1, characterized in that the oligomeric acrylate or methacrylate has an average molecular weight of 300-1,000.

### Claim 3 (depends on 1, 2)

An optically readable information disk as claimed in claim 1 or 2, characterized in that the lacquer comprises at least 90% by weight of an epoxylated or alkoxylated bisphenol and/or Novolak each comprising on an average per molecule between one and three acrylate groups or methacrylate groups.

### Claim 4 (depends on 3)

An optically readable information disk as claimed in claim 3, characterized in that the lacquer comprises an alkylene-bis(phenoxyalkylmethacrylate) or an alkylene-bis(phenoxyalkylacrylate).

### Claim 5 (depends on 4)

An optically readable information disk as claimed in claim 4, characterized in that the lacquer comprises 1,1'-isopropylene-bis(p-phenoxyethylmethacrylate) or 1,1'-isopropylene-bis-(p-phenoxyethylacrylate).

### Claim 6

A method for manufacturing an optically readable information carrier, said information carrier being a self supported radiation cured synthetic resin disk, characterized in that a radiation-curable liquid composition which comprises oligomeric acrylates or methacrylates which on an average comprise per molecule between 1 and 4 acrylate groups or methacrylate groups, which liquid composition has a viscosity of 1,000-15,000 cP and comprises a photoinitiator in a concentration of 0.1 to 0.5% by weight, is introduced into a moulding cavity formed between two parallel arranged matrices, at least one of the two matrices on its surface facing the other matrix having an information track which has a relief structure of information areas situated alternately at a higher and a lower level, the introduced layer is then cured by radiation via one or both matrices and the resultant cured disk in which the information track has been copied is removed from the mold after opening the matrices and, if desired, is provided with a reflective layer on the side of the information track.

### Claim 7 (depends on 6)

A method as claimed in claim 6, characterized in that one of the matrices is movable, in which the matrix, during the shrinkage of the liquid occurring upon curing, remains adhered to the surface of the liquid layer and, under the influence of the shrinkage forces exerted on the matrix, moves without deformation in a direction perpendicular to the matrix surface, so that as a result of this the shrinkage of the liquid layer results exclusively or substantially exclusively in a dimension variation of the liquid layer in a direction perpendicular to the surface of the matrices.