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. 03, 1996
Filed:
Jul. 12, 1994
Masaru Ito, Sagamihara, JP;
Masumi Fujita, Toride, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi Maxell, Ltd., Osaka, JP;
Abstract
An optical disk master having a diffraction structure including guide grooves and small pre-pits of a width narrower than a diffraction limit determined by a wavelength of light used is produced by preparing a photoresist layer subjected to anti-dissolution surface treatment, narrowing the spot diameter of a zero-th diffracted beam irradiated on the photoresist layer by a super resolution optics device, and effecting high contrast development to leave behind, as it is, a portion of the photoresist layer exposed to adverse higher order diffracted beams caused by super resolution. An optical disk produced from the master has a diffraction structure including tracks and/or pre-pits formed along a spiral track or concentric tracks and having a width narrower than a diffraction limit determined by a wavelength of light used in the course of formation of the diffraction structure.