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. 21, 1986
Filed:
Oct. 12, 1983
Tomio Yoshida, Katano, JP;
Isao Satoh, Neyagawa, JP;
Shunji Ohara, Higashiosaka, JP;
Kenji Koishi, Hyogo, JP;
Yuzuru Kuroki, Moriguchi, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical and reversible recording and reproducing apparatus providing a practical apparatus in which information signals can be recorded, reproduced and erased by irradiating a laser beam and the like on the substrate to be optically recorded. More practically, there is provided such an apparatus wherein two light sources such as lasers having different wavelengths are used, and a first almost circular micro-lightspot is produced by one light source, while a second elliptic light spot having a longitudinal diameter in the tangential direction of a guide track on a disc is produced by the other light source. These first and second light spots are closely irradiated on one and the same guide track of an optical recording disc. The recording and reproducing of the signals are performed using the first light spot while the erasure of the recorded signals can be made by using the second light spot or using both first and second light spots in combination.