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:
Jul. 07, 1998
Filed:
Feb. 23, 1996
Industrial Technology Research Institute, Hsinchu, TW;
Abstract
An objective lens for an optical disk drive is disclosed. The objective lens comprises four portions each having a aspherical surface for focusing a light beam of a designated wavelength to a designated focal point. The first portion has a first aspherical surface that focuses the light beam to a first focal point. The second portion has a second aspherical surface that focuses the light beam to a second focal point. The third portion has a third aspherical surface featuring the same surface curvature characteristics as that of the first aspherical surface and focuses the light beam to the first focal point. And, the fourth portion has a fourth aspherical surface featuring the same surface curvature characteristics as that of the second aspherical surface and focuses the light beam to the second focal point. The objective lens can be made as a single-piece lens that suffers no energy loss for either focusing.