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. 11, 1991
Filed:
May. 17, 1989
Isao Satoh, Neyagawa, JP;
Yoshihisa Fukushima, Osaka, JP;
Makoto Ichinose, Sakai, JP;
Yuzuru Kuroki, Toyonaka, JP;
Yuji Takagi, Neyagawa, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A read only type optical disc, and disc drive apparatus for reading/additionally writing data into the disc. The disc has a recording material formed in all of the tracks by which data can be additionally recorded on the disc. This optical disc has a plurality of sectors forming a data read-only area and a write/read area. Each area has track sectors each having a sector identifier portion in which address information is recorded and a data field portion to record data. Data-field identification flags indicativ of the read-only area and the write/read area are recorded in the respective identifier portions. On reading or writing this optical disc, the data field identification flag is detected to identify the kind of related area i.e., rea-only area or write/read area. Thus, it is possible to avoid erroneous recording of data into the read-only area. Upon reading operation, waveform equalization and binary-clipping level of reproduction signals can be well controlled. The gain of the servo loop can be switched. The track searching operation can be stably performed. The data reading and data writing into the data write/read area can be improved.