Objective lens for optical disks
US4953959A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 1989 |
| Grant date | Sep 4, 1990 |
| Priority date | — |
| Expiry date | May 8, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/13727
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An objective lens for optical disks comprises a first lens component and a second lens component and, when the distance on an optical axis from an entrance face of the first lens component disposed in a position farthest from an optical disk to the center of gravity of the objective lens is taken as gc, the overall length of the objective lens as .SIGMA. d, and the focal length as f, the following conditions are satisifed and any of surfaces of the lens components is configured as an aspherical surface: EQU g c<.SIGMA.d<0.5 EQU 0.9<.SIGMA.d/f<2.2 Thus, the use of the objective lens makes it possible to reduce the load to a driving device for moving the objective lens and to provide the driving device small in size and light in weight.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.