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. 12, 1993
Filed:
Oct. 03, 1991
Milton R Latta, San Jose, CA (US);
Timothy C Strand, San Jose, CA (US);
James M Zavislan, San Jose, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A mask is used to remove substantially all of the first order diffraction components of a reflected light beam which are generated as the beam crosses grooved data tracks in an optical media. The mask may comprise a transparent substrate with an opaque layer having a pair of circular apertures or a bow-tie shaped aperture. The apertures are located outside the regions of interference between the diffracted components and the undiffracted component. The layer may be made of a reflective material for reflecting diffracted components of the reflected beam to a tracking error sensor. The layer may be made of a holographic material for deflecting the diffracted components to a tracking error sensor.