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:
Apr. 03, 2007
Filed:
Apr. 18, 2003
Takashi Namioka, Tokyo, JP;
Yasufumi Takasugi, Tokyo, JP;
Kazuo Fukunaga, Tokyo, JP;
Toshikazu Hosobuchi, Tokyo, JP;
Giichi Shibuya, Tokyo, JP;
Hideki Hirata, Tokyo, JP;
Kazuki Suzawa, Tokyo, JP;
Takashi Namioka, Tokyo, JP;
Yasufumi Takasugi, Tokyo, JP;
Kazuo Fukunaga, Tokyo, JP;
Toshikazu Hosobuchi, Tokyo, JP;
Giichi Shibuya, Tokyo, JP;
Hideki Hirata, Tokyo, JP;
Kazuki Suzawa, Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
The present invention provides a method and an apparatus for discriminating the type of an optical recording medium and the number of recording layers in the medium. The apparatus includes a first electrode and a second electrode placed in the vicinity of a light transmission layer of the recording medium, an alternating current signal generation circuit for applying an alternating current A to the first electrode, a detection circuit for detecting the level of an alternating current B appearing at the second electrode, and a control circuit for controlling the operations of the alternating current signal generation circuit and the detection circuit, and a table provided in the control circuit.