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:
Jan. 17, 1989
Filed:
Oct. 03, 1986
Isao Satoh, Neyagawa, JP;
Makoto Ichinose, Sakai, JP;
Yoshihisa Fukushima, Osaka, JP;
Yuzuru Kuroki, Toyonaka, JP;
Yuuji Takagi, Neyagawa, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A data recording and reproducing apparatus is disclosed in which an optical disc for recording, reproducing or erasing data is radiated with an erasing light beam and a recording-reproducing light beam sequentially to record or reproduce the data with the recording-reproducing light beam and erase the data with the erasing light beam. In rewriting the data, the erasing light beam is radiated in advance of the recording-reproducing light beam on a data section of the disc, and the old data is erased by temperature increase and annealing by the erasing light beam, while new data is recorded by temperature increase and quenching with the recording-reproducing light beam set to the recording light intensity. After recording the new data, the light intensity of the erasing light beam is gradually decreased and turned off. In rewriting the sector data, the erasing light beam is radiated on the data section in advance of the recording-reproducing light beam, and by the temperature increase and annealing with the erasing light beam, the old data is erased, while new data is recorded by temperature increase and quenching with the recording-reproducing light beam set to the recording light intensity. After recording the new data, the light intensity of the erasing light beam is turned off after being modulated for a predetermined time. By doing so, the process of the temperature and quenching is eliminated which otherwise might be required at the time of turning off the erasing light beam, thereby preventing occurrence of a recording trace and a defect of the recording medium by a thermal shock.