Objective lens driving device with multipole magnet
US4792935A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 1986 |
| Grant date | Dec 20, 1988 |
| Priority date | — |
| Expiry date | Dec 22, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K2201/18
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An objective lens driving device with a multipole magnet which includes a cylindrical yoke with an E-shaped cross section for defining an annular gap between the central yoke section and the outer cyclindrical yoke section; four rectangular tracking coils attached to the side of a focusing coil such that a pair of vertical coil sides of each tracking coil are parallel to a supporting shaft; and a pair of circular multipole magnets disposed within the gap between the central and outer cylindrical yoke sections and each having at least three magnet sections, with opposite end magnet sections having a polarity opposite to that of the central magnet section so that the vertical coil sides interlink with magnetic fluxes having opposite directions to each other, whereby tracking forces act upon the vertical coil sides in the same direction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.