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:
Nov. 04, 1997
Filed:
Apr. 06, 1995
Wataru Kubo, Tokyo, JP;
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
An opto-magnetic head apparatus including a beam splitter for splitting laser light reflected from a photomagnetic recording medium into three bundles of light having different polarization directions in a specific plane. One of the three bundles of light is used as a servo-signal and the remaining two bundles of light are used as a data-signal. A diffracting element, which splits at least the bundle of light used as a servo signal into two bundles of light in a direction perpendicular to the direction in which the splitting of the laser light by the beam splitter occurs, provides a predetermined amount of positive or negative defocus to the bundles of light split by the diffracting element. The opto-magnetic head apparatus also includes a pair of servo-signal light receiving elements which receive the bundles of servo-signal light split by the diffracting element and which are located in a plane normal to the optical axis. Two data-signal light receiving elements, which receive the bundles of the data-signal light, are located in the same plane as the servo-signal light receiving elements.