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:
Mar. 29, 1988
Filed:
Mar. 18, 1987
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
The combination of recordable-reproduceable optical discs and reproducing-only optical discs and an optical disc player which is capable of reproducing recorded signals both from the recordable-reproduceable optical disc possessing pregrooves and the reproducing-only optical disc possessing recording pits by means of a common optical system. The common optical system has a common laser for irradiating both types of discs with a laser beam used for reading the discs. The wavelength of the laser is .lambda. and the depth or height of the pregrooves of the recordable-reproduceable optical disc is made equal to or less than .lambda./8n, and the depth or height of the recording pits of the reproducing-only optical disc is made equal to or greater than .lambda./8n but less than .lambda./4n, wherein n is the refractive index of the substrate of the disc or the protective layer provided on the surface thereof.