Servo-controlled actuator with two-peak flux density distribution
US5073882A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 26, 1989 |
| Grant date | Dec 17, 1991 |
| Priority date | — |
| Expiry date | Sep 26, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0935
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A lens actuator comprises a permanent magnet which generates a magnetic flux density distribution having two peaks of equal magnitudes, the two peaks being located symmetrically on opposite sides of a center axis of the distribution and arranged in a first direction perpendicular to the center axis. A pair of first coils and a second coil are mounted on a resiliently movable support. The first coils have first coil sections which cooperate with the magnetic flux to generate force components contributing to movement of the support in a second direction perpendicular to the first direction and second coil sections which cooperate with the magnetic flux to generate force components not contributing to the movement of the support in the second direction. The second coil sections of the first coils are located respectively at the peaks of the magnetic flux density distribution. The second coil cooperates with the magnetic flux to produce a force component that moves the support in the first direction. Because of the two peaks, flux densities do not substantially differ between upper and lower sections of the first coils when they are moved in a focusing direction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.