Objective lens and optical pick-up apparatus
US7187641B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 3, 2004 |
| Grant date | Mar 6, 2007 |
| Priority date | — |
| Expiry date | Sep 1, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1374
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An objective lens has a first meniscus-shape lens including a first object-side surface having a positive reflective power; and a second meniscus-shape lens having a positive reflective power. The first meniscus-shape lens and the second meniscus-shape are arranged in that order from an object side. The objective lens satisfies the following formulas:fF/f≦−1.1 LH1H2/f≧0.5 fB/f≧0.2 L/f≦1.3 where f is an object-side focus length of the objective lens, fF is a front focus, fB is a back focus, LH1H2 is a length between an object-side principal point H1 and an image-side principal point H2, and L is a length on an optical axis of the objective lens between the first object-side surface and the second image-side surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.