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:
Jun. 25, 2002
Filed:
Feb. 17, 2000
Koichi Moritani, Yokohama, JP;
Akemi Hirotsune, Higashimurayama, JP;
Motoyasu Terao, Hinode, JP;
Yasushi Miyauchi, Akishima, JP;
Toshimichi Shintani, Kodaira, JP;
Takashi Naito, Hitachiota, JP;
Takashi Namekawa, Hitachi, JP;
Hiroki Yamamoto, Hitachi, JP;
Other;
Abstract
The optical recording medium has sandwiched between protective layers a mask layer whose refractive index is changed in one part within a light spot when irradiated with a laser beam of 2 to 4 mW. In a region where the refractive index is changed or in other remaining regions, the difference in the amount of reflected light between the crystalline state and the amorphous state is so small that a reproduced signal is difficult to identify. By reducing the size of a portion where the reproduced signal can be seen, it is possible to read high-density recorded information.