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:
Oct. 06, 1998
Filed:
Oct. 29, 1996
Masumi Ono, Tokyo, JP;
Sony Corporation, Tokyo, JP;
Abstract
It is an object of the present invention to increase an amount of information recorded on an optical disk having at least two information recording layers. An optical disk having a plurality of information recording layers according to the present invention includes a transparent substrate, a transparent layer and at least two information recording layers formed on the transparent substrate. The information recording layers are provided so as to sandwich the transparent layer. At least one of the information recording layers has a transmittance varying layer. The transmittance varying layer is made of a material whose transmittance is changed at a predetermined temperature as a threshold value. The transmittance varying layer is made of a phase change material. The threshold value is within the temperature range from 700.degree. to 500.degree.. Crystallization speed of the transmittance varying layer is equal to or slower than 500 ns.