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:
Nov. 03, 1998
Filed:
Jul. 25, 1996
Shin-Ichi Yamada, Oosakafu, JP;
Mitsurou Moriya, Naraken, JP;
Yasuaki Edahiro, Osakafu, JP;
Kouichi Takamine, Oosakafu, JP;
Katsuya Watanabe, Osakafu, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical disk apparatus comprising a device for moving a focal point of a light beam for reproducing information recorded on an information face of a disk, in the direction perpendicular to the information face; a device for detecting a reflected light from the disk; and a device for discriminating whether the disk set in the apparatus is a disk having a thick base substrate or a disk having a thin base substrate. In this apparatus, a maximum value AS1L.sub.max of an output signal from the reflected light detecting device and a maximum value ENV.sub.max of an amplitude of an information reproducing signal are detected while driving the focal point moving device so that the focal point passes through the information face, and the discriminating device discriminates whether the disk set in the apparatus is a disk having a thick base substrate or a disk having a thin base substrate, on the basis of the ratio of ENV.sub.max to AS1L.sub.max. Therefore, it is possible to discriminate between a DVD having a thin base substrate and a CD having a thick base substrate.