The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 05, 2000
Filed:
Jun. 11, 1997
Takashi Ohno, Kanagawa, JP;
Masaaki Mizuno, Kanagawa, JP;
Masae Kubo, Kanagawa, JP;
Kanako Tsuboya, Kanagawa, JP;
Michikazu Horie, Kanagawa, JP;
Mitsubishi Chemical Corporation, Tokyo, JP;
Abstract
An optical information recording medium comprising a substrate provided with periodically wobbling guide grooves with a track pitch of 1.6.+-.0.1 .mu.m, and a lower protective layer, a phase-change type recording layer, an upper protective layer and a reflective layer formed in this sequence on the substrate, for recording, retrieving and erasing amorphous marks in the guide grooves by modulation of light intensity of at least two levels by means of a focused light having a wavelength of 780.+-.30 nm applied from the side of the substrate opposite to the recording layer side so that a crystalline state with a reflectance of from 15 to 25% is an unrecorded state, and an amorphous state with a reflectance of less than 10% is a recorded state, wherein the grooves have a depth of from 25 to 45 nm and a width of from 0.4 to 0.6 .mu.m.