Pioneer Electronic Corporation

Kunizo Ogoshi

Tetsuya Iida

Takanobu Higuchi

Shinichi Yokozeki

Hironao Sasaki

An optical disc is prepared by the steps of coating a positive photoresist comprising a photosensitive material and a base resin, satisfying a value of A in a formula A&equals;(a,&minus;a,) m,and a value of B in a formula B&equals;(a,m,&plus;a,m,), being constant, is in a range of B value <,on a glass substrate to form a resist film, forming a pit pattern through a light exposure to the resist film, developing the resist film after the light exposure to form a resist original, effecting a plating treatment to the resist original to form a stamper through an electrocasting treatment, forming a replica disc through an injection molding process by utilizing the stamper, forming a reflection film on the replica disc, and forming an overcoat layer on the reflection film.

Photoresist for optical disc and method of preparing optical disc utilizing photoresist

An optical information record carrier (optical disk, conventionally) has multiple reflective surfaces, each carrying separate information and each readable by an optical beam directed from the same side of the record carrier. The top most reflective surface reflects light of a first waveband and passes light of a second waveband. The next top most reflective layer reflects light within at least part of the second waveband. The record carrier is formed by producing a first reflective layer having a first pit pattern in the surface of a transparent substrate, pressing said first substrate/layer combination to a transparent stamper having a second pit pattern, with a radiation hardening liquid resin therebetween, irradiating the resin by applying radiation to said resin through said stamper, peeling off said stamper, applying a second reflective layer to said hardened resin surface opposite the surface in contact with said first reflective layer, and applying a protective layer to said second reflective layer.

Method of producing an optical information record carrier

An optical information record carrier (optical disk, conventionally) has multiple reflective surfaces, each carrying separate information and each readable by an optical beam directed from the same side of the record carrier. The top most reflective surface reflects light of a first waveband and passes light of a second waveband. The next top most reflective layer reflects light within at least part of the second waveband. The record carrier is formed by producing a first reflective layer having a first pit pattern in the surface of a transparent substrate, pressing said first subtrate/layer combination to a transparent stamper having a second pit pattern, with a radiation hardening liquid resin therebetween, irradiating the resin by applying radiation to said resin through said stamper, peeling off said stamper, applying a second reflective layer to said hardened resin surface opposite the surface in contact with said first reflective layer, and applying a protective layer to said second reflective layer.

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Saitama, Japan

Kunizo Ogoshi