Diaphragm electromagnetic drive device
US5140212A · kind A · utility
22Cited by
11References
1Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 13, 1990 |
| Grant date | Aug 18, 1992 |
| Priority date | — |
| Expiry date | Nov 13, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K21/12
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A diaphragm electromagnetic drive device which comprises ring-shaped rotor and stator disposed coaxially about the optical axis of a taking lens and in which the rotor is rotated to thereby rotate diaphragm blades so as to vary successively a diaphragm diameter defined by the diaphragm blades. The mutually opposed surfaces of the rotor and stator are constructed respectively in the shape of a side surface of a truncated cone, so that the areas of the opposed surfaces can be increased without increasing the outside diameter and the length in the optical axis direction of the electromagnetic drive device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.