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:
Aug. 14, 1990
Filed:
Dec. 07, 1987
Yuji Takagi, Kadoma, JP;
Isao Satoh, Neyagawa, JP;
Makoto Ichinose, Sakai, JP;
Yoshihisa Fukushima, Osaka, JP;
Yuzuru Kuroki, Toyonaka, JP;
Yasushi Azumatani, Neyagawa, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
In a read only type optical disk and a write type optical disk each thereof having a data recording area and a spare area, first encoded data for error detection and correction are recorded in the data recording area. In the case of the read only type optical disk, the spare area is used as a check sector in which second encoded data are recorded. When error correction by first error control means becomes impossible while sectors in the data recording area are reproduced, second error control means performs error correction by using the check sector corresponding to an associated error sector. In the case of the write type optical disk, the spare area is used as an alternate sector. A defective sector detected by defective sector detecting means is alternately recorded by being replaced by the alternate sector through sector alternating means.