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:
Dec. 11, 1990
Filed:
Apr. 28, 1988
Hiroshi Sukawa, Yokohama, JP;
Sumio Hirose, Yokohama, JP;
Shigeru Takahara, Kamakura, JP;
Tomoyoshi Sasakawa, Tokyo, JP;
Mitsui Toatsu Chemicals, Incorporated, Tokyo, JP;
Yamamoto Chemicals, Incorporated, Yao, JP;
Abstract
This invention relates to an optical recording medium characterized by high sensitivity, high stability, etc, and a process for making the optical recording medium. Specifically, the present invention provides an optical recording medium composed of a transparent substrate having prepits and/or pregrooves for system control signals and first and second recording layers formed thereon in order, the both layers having individually a specific reflectance, transmittance and absorbance. To the optical recording medium, a laser beam is irradiated on the transparent substrate side to record or read out information and, by detecting the variation of the amount of light as a sum of the reflected light from the boundary between the first recording layer and the substrate and the reflected light from the boundary between the second recording layer and the air, the system control signals are primarily obtained from the prepits and/or pregrooves. Regarding the two recording layers, the first recording layer contains an organic dye having a transmittance of 10-50% and an absorbance of 40% or more against the wavelength of a laser beam used for writing while the second recording layer contains an organic dye having an absorbance of 20% or less and a reflectance of 25% or more at the air boundary at the wavelength region of the laser beam. The optical recording medium can be made in accordance with the process of the present invention wherein (a) a transparent substrate having prepits and/or pregrooves for system control signals is provided, (b) two kinds of solution are prepared by allowing two organic dyes each soluble exclusively in either a low-polar solvent or else a high-polar solvent to dissolve in the respective counterpart solvent, and (c) the two kinds of dye solution are applied on the transparent substrate in series to form the first recording layer and the second recording layer.