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.

Date of Patent:
Jun. 22, 2004

Filed:

Feb. 17, 2000
Applicant:
Inventors:

Tetsuya Fushimi, Hitachinaka, JP;

Toshimitsu Kaku, Sagamihara, JP;

Hisataka Sugiyama, Kodaira, JP;

Assignee:

Hitachi, Ltd., Tokyo, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B 7/00 ;
U.S. Cl.
CPC ...
G11B 7/00 ;
Abstract

In an optical information recording/reproducing apparatus, in which two sets of circuits (including a comparator and a time counting device (i.e., pulse width detector), and a comparator and a time counting device (i.e., pulse width detector)) are provided for detecting that the fluctuation larger than a comparison level continues in the TE signal for a time period, each being set at the respective comparison level and the time duration, differently, thereby the operation of write or erase onto an optical disc is stopped even if only one of them is detected. Also, a position or location information in the PID portion to be reproduced, being outputted from a PID register , and a location information which is read out by the PID decoder are compared by a comparator , thereby stopping the operation of write or erase onto the optical disc if they are inconsistent with.


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