Objective lens for a pickup optical system
US5936782A · kind A · utility
23Cited by
4References
11Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 2, 1998 |
| Grant date | Aug 10, 1999 |
| Priority date | — |
| Expiry date | Mar 2, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/13722
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An objective lens for a pickup optical system for optically reading out information recorded in a recording medium , includes a first lens body and a second lens body integrally attached to a surface of the first lens body and having a micro Fresnel portion for focusing light to a predetermined position of the recording medium. When the objective lens is used for a pickup optical system, the micro Fresnel portion faces away from an accommodation region for accommodating the recording medium to prevent dust from attaching to the micro Fresnel portion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.