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. 14, 1995
Filed:
Jul. 31, 1992
Hiroshi Omata, Kawasaki, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An optical recording medium is provided with optical guide grooves and prepits representing for example address data, in a land portion sandwiched between the grooves. The reflectivity in the bottom portion of the prepits is made higher than that of the land portion. An antireflection film is provided on the medium such that, in case where the reflectivity of the antireflection film decreases with the increase in the thickness of the antireflection film, the thickness of the antireflection film on the bottom of the prepits is selected smaller than that on the land portion. In the case where reflectivity of the antireflection film increases with the increase in the thickness of the antireflection film, the thickness of the antireflection film on the bottom of the prepits is selected larger than that on the land portion.