Shutter apparatus for camera
US4851870A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 20, 1988 |
| Grant date | Jul 25, 1989 |
| Priority date | — |
| Expiry date | Apr 20, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B7/083
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The disclosure relates a piezoelectric element-drive type shutter apparatus for camera. The shutter apparatus includes a main piezoelectric element having a free end which is able to move between a closed position and an opening position to drive shutter blades so as to be opened and closed, and an auxiliary piezoelectric element having a free end for urging the shutter blades toward its closed position when the free end of the main piezoelectric element returns from the opening position to the closed position. When the main piezoelectric element returns to the closed position, i.e. an initial position, the auxiliary piezoelectric element assists the returning movement of the main piezoelectric element. Accordingly, the shutter blades can be closed at a very high speed. This is very effective particularly when a small aperture of the shutter blade is desired. Furthermore, since the returning movement of the main piezoelectric element includes a compulsory force of the auxiliary element as well as a returning force of itself, the returning movement of the main piezoelectric element is insured to be stable as well as speedy, so that very accurate exposure can be obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.