Driving apparatus, light-amount regulating apparatus, and lens driving apparatus
US6781772B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 1, 2003 |
| Grant date | Aug 24, 2004 |
| Priority date | — |
| Expiry date | Jul 1, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K26/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A driving apparatus includes a rotatable rotor with a ring shape, a first magnetic pole portion, a second magnetic pole portion, and a coil for magnetically exciting the first magnetic pole portion and the second magnetic pole portion. The rotor has magnet portions which are divided along a circumferential direction and differently magnetized. The coil is disposed radially of the rotor. The condition of −0.333X+0.7>Y is satisfied where Y is a ratio of a central angle of each first magnetic pole portion relative to a central angle of each magnetized pole in the magnet portion, and X is a ratio of an outer circumferential length of each magnetized pole in the magnet portion relative to a thickness of the magnet portion in a direction of the rotational axis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.