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:
Feb. 13, 2001
Filed:
Jun. 30, 1999
Takatoshi Yamada, Kanagawa, JP;
Norio Fukasawa, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical lens composed of a transparent material, wherein one surface thereof on a light source side is a convex aspherical surface of rotation symmetry defined by a function relative to the radial distance from an optical axis. The aspherical surface is shaped to be a curved one without any stepped region with regard to the radial direction in the defined area, and has a portion where the derivatives of the function are discontinuous at a predetermined radial position. Although not equipped with an iris diaphragm, this optical lens is capable of eliminating an incident light beam outside the optical effective surface thereof without deteriorating the optical characteristics.