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:
Oct. 03, 1995
Filed:
Jan. 22, 1993
Yumiko Ohashi, Hashima, JP;
Brother Kogyo Kabushiki Kaisha, Nagoya, JP;
Abstract
An optical recording medium affording a maximum Kerr effect enhancement, yet exhibiting a good signal-to-noise ratio, includes, for example, a substrate, an interference layer, a tracking guide layer, and a recording layer which are successively formed one above the other in the stated order. The interference layer is made of a light transmissive material and has a refractive index that is larger than that of the substrate. The interference layer has a first portion etched to a predetermined depth (d) and a second portion having a predetermined thickness (D). The tracking guide layer is formed on the second portion of the interference layer in a predetermined pattern, e.g. spirally or coaxially, for obtaining a tracking signal for use in tracking servo. The thickness of the interference layer defined by D minus d is set substantially equal to (.lambda./4n)+M(.lambda./2n) where .lambda. is a wavelength of light for reading the information, n is a refractive index of the interference layer, and M is an integer.