Objective lens drive unit
US5303089A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 27, 1993 |
| Grant date | Apr 12, 1994 |
| Priority date | — |
| Expiry date | May 27, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0933
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an objective lens drive unit, a magnetic circuit is constructed by two outer yokes, two inner yokes, a magnet and an upper yoke. The magnetic circuit applies a magnetic field to each of electromagnetic coils disposed in a bobbin having an objective lens. The outer yokes and the inner yokes are integrally formed with an actuator base. A through hole is formed in the upper yoke composed of one sheet metal such that a light beam transmitted through the objective lens passes through the through hole. Each of the inner yokes is inserted into the through hole and both end portions of the upper yoke are arranged and fixed to the two outer yokes such that an arranging state of the upper yoke is stabilized. Thus, the upper yoke is simply, reliably and precisely fixed to the inner and outer yokes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.