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. 01, 1993
Filed:
Dec. 28, 1989
Hiroyuki Imataki, Kawasaki, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An optical recording medium is formed by applying a coating liquid to form a light-reflecting layer on a substrate having a surface provided with a pre-format pattern comprising a concavity and a convexity. The concavity is designed to have a sectional shape of a trapezoid having a pair of parallel opposite sides, a shorter one of which constitutes the bottom of the concavity, and a pair of sloping sides. Each sloping side forms a (solid part) angle .theta. of not larger than 35 degrees with respect to the extension of the substrate surface. The concavity has a depth d larger than .lambda./4n wherein .lambda. is the wavelength of an optical radiation beam with which the optical recording medium is illuminated for recording and/or reproduction and n is the refractive index of the substrate.