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:
Mar. 07, 1995
Filed:
May. 26, 1993
Katsumi Kawahara, Kadoma, JP;
Takeo Ohta, Nara, JP;
Shigeaki Furukawa, Shiki, JP;
Tetsuya Akiyama, Habikino, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
In a record medium wherein information is recorded and/or erased by changing the optical state thermally by the irradiation with a laser beam or the like, a protection layer made from a material having a larger thermal conductivity than adjacent protection layers is used to decrease the temperature difference between the center and edges of a record mark on recording and/or erasing with a laser beam. By using the material having a larger thermal conductivity, the heat due to the irradiation with a laser beam or the like is diffused not only to the periphery of the substrate, but also to the plane of the substrate surely. Therefore, the temperature difference between the center and the edges in a mark on irradiation with the laser beam is decreased, and the recording/erasing characteristics and the power margin for erasing can be improved.