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. 28, 1995
Filed:
May. 27, 1993
Naoaki Tani, Hachioji, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
In an optical head for reading information signals out of a plurality of information tracks on an optical record medium by projecting a slit-like light spot onto the optical record medium, a laser beam having a substantially elliptical cross section is passed through a stop having an aperture to shield both edge portions of the laser beam to obtain a laser beam having a uniform distribution. Then, the laser beam emanating from the stop is made incident upon a cylindrical lens have a negative power in a direction of a major axis of the laser beam to form a laser beam having a uniform distribution in a longitudinal direction. The thus obtained laser beam is projected onto the optical record medium by an objective lens such that the longitudinal direction of the slit-shaped laser beam spot is aligned with a direction substantially perpendicular to a track direction in which information tracks extend. In this manner, a plurality of information tracks are simultaneously illuminated uniformly, so that it is possible to obtain a plurality of information signals having substantially the same level.