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:
Jul. 07, 1987
Filed:
May. 31, 1985
Tomio Yoshida, Katano, JP;
Shunji Ohara, Higashiosaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
Disclosed is an optical recording and reproducing apparatus having an erasing function. The invention aims at providing a practical apparatus which can effect recording, reproducing and erasing of signals in an erasable recording film by applying laser beams thereto. A substantially circular first fine beam spot is formed by a beam source such as a laser, and an elliptic second beam spot for erasing purposes is formed by another beam source such as a laser, with both beam spots are disposed in close proximity of each other on the same guide track. The erasing beam spot is elongated and has an axis which is tangent to the guide track on the recording medium. The power of intensity profile of the erasing beam spot is so controlled that the highest intensity is obtained at the leading end portion of the erasing beam spot as viewed in the direction of the scan, so that the signal can be erased stably and reliably with minimal erasing power. The portion of the recording medium scanned by the erasing beam spot is scanned by the recording beam spot so that the erasing and recording are carried out substantially simultaneously.