Hitachi, Ltd.

Naotake Ebinuma

Nobuhiro Tokushuku

Katashi Hazama

Hitoshi Yanagihara

Masaki Yoshii

An optical disc consists of a base plate, a reflective thin layer, and a protective thin layer. The optical disc has a sample mark area having two sample marks, one of which is off-set on one side of a track, another of which is off-set at an opposite side of a track. These sample marks are produced by an injection molding with replica technique. At the time of the injection molding, additional pressure moves soft injected plastic resin, which causes double transcription of the sample marks. For preventing the double transcription, groove areas are provided on opposite sides of the sample mark area. The groove areas provide an anchor effect at the time of injection molding.

Growing community of inventors

Hayama-machi, Japan

Naotake Ebinuma