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:
May. 16, 2000
Filed:
Jan. 19, 1999
Shuichi Okubo, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A first dielectric layer, a second dielectric layer, a third dielectric layer, a recording layer, a fourth dielectric layer, and a reflective layer are provided in that order on a substrate to constitute a phase-change type optical disk. The first dielectric layer, the second dielectric layer, and the third dielectric layer are constructed to satisfy the relationships: n1>n2 and n3>n2 wherein n1 represents the refractive index of the first dielectric layer, n2 represents the refractive index of the third dielectric layer, n3 represents the refractive index of the second dielectric layer. According to the above construction, the light reflectance of the amorphous area can be increased to lower the light absorption of the amorphous area, realizing inhibition of cross erasing. Further, since no light absorptive layer is present between the substrate and the recording layer, the temperature rise around the surface of the substrate can be inhibited to reduce the thermal deformation of the substrate. This can improve rewrite cycling properties.