Matsushita Electric Industrial Co., Ltd.

Keiichiro Horai

Kenichi Nishiuchi

Hiroaki Irie

Mitsuaki Oshima

Yoshihisa Fukushima

Noboru Yamada

Rie Kojima

Takeo Ohta

Katsumi Kawahara

Kazumi Yoshioka

Masami Uchida

Toshiaki Kashihara

A main information areacapable of recording an information signal and a subsidiary information areafor recording subsidiary information that is different from the information signal are divided in one principal plane direction of a substrate, and an information layer for recording the information signal in the main information areais provided also in the subsidiary information area, and medium identification information for distinguishing the medium optically is recorded in the information layer of the subsidiary information areawithout changing the shape of the information layer. As a result, the medium identification information can be recorded in an optical recording mediumstably. In particular, the initialization of a phase change type optical recording medium and the recording of the medium identification information can be performed at the same time, so that the production process can be simplified, and the production costs can be reduced.

Optical recording medium and recording method for the same

A main information areacapable of recording an information signal and a subsidiary information areafor recording subsidiary information that is different from the information signal are divided in one principal plane direction of a substrate, and an information layer for recording the information signal in the main information areais provided also in the subsidiary information area, and medium identification information for distinguishing the medium optically is recorded in the information layer of the subsidiary information areawithout changing the shape of the information layer. As a result, the medium identification information can be recorded in an optical recording medium 1 stably. In particular, the initialization of a phase change type optical recording medium and the recording of the medium identification information can be performed at the same time, so that the production process can be simplified, and the production costs can be reduced.

An optical information recording medium having a recording layer for inducing a reversible phase change by irradiation with energy beam. The recording layer contains Te, Ge, Sb, and N, and the concentration of the N being contained is in a range of about 0.1% by atom to about 10% by atom. In this constitution, an excellent repeated recording and erasing performance is obtained.

Optical information recording medium and method of manufacturing the same

A method of depositing the layers of an optical recording medium to their requisite thicknesses is disclosed in which optical monitoring of the reflectivity of a first dielectric layer during deposition is used to determine the deposition rate. The reflectivity is monitored to determine the time period in which the reflectivity reaches a maximum or minimum value, which occurs when the layer is a quarter wave thick. The deposition rate is derived from that time period, and the deposition is continued for a time in accordance with the deposition rate until the requisite thickness of the first dielectric layer is obtained. The second dielectric layer is deposited for a lesser time period in accordance with the deposition rate which has been optically derived during deposition of the first dielectric layer.

Process for manufacturing an optical recording medium

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Sanda, Japan

Keiichiro Horai