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. 18, 1997
Filed:
Nov. 21, 1994
Jun-ichi Takahashi, Tokyo, JP;
NEC Corporation, , JP;
Abstract
A light radiated from a light source is focused to provide a light spot on an optical disc. A central portion of the radiated light is shielded, and a peripheral portion of the radiated light is modulated to have an intensity decreasing in an outer periphery direction, respectively, by a light intensity modulator. Consequently, a diameter of the light spot is reduced, and side-lobes are suppressed. In place of the light intensity modulator, a light source filter and a second filter are used. A secondary light source is formed by focusing the radiated light. At a point of the secondary light source, the light source filter having a central portion of 0% and a peripheral portion of 100%, respectively, in light transmission intensity is provided. On an output side of a collimator lens, the second filter having central portion of 100% and a peripheral portion of 0%, respectively, in light transmission intensity is provided.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile