Lens device comprising light blocking means and an optical pickup apparatus using the lens device
US5665957A · kind A · utility
72Cited by
19References
41Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 1, 1996 |
| Grant date | Sep 9, 1997 |
| Priority date | — |
| Expiry date | May 1, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/808
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A lens device which can be used as an objective lens in an optical pickup apparatus includes an objective lens provided along a light path facing a disc and having a predetermined effective diameter, and light controlling means provided along the light path for controlling the light in an intermediate region between near and far axes of an incident light beam, thus providing a simplified and inexpensive device for using discs of differing thickness in a single disc drive, by reducing the spherical aberration effect.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.