Device for controlling an amount of light allowed to reach a photosensitive surface
US5706120A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 1996 |
| Grant date | Jan 6, 1998 |
| Priority date | — |
| Expiry date | Apr 24, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B9/16
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A device for controlling an amount of light allowed to reach a photosensitive surface includes a movable light regulating member, an electrically conductive coil mounted to move with the member, a first permanent magnet having a north pole located adjacent a first side of the coil, and a second permanent magnet having a south pole located adjacent the first side of the coil. The invention is characterized by third and fourth permanent magnets located adjacent a second side of the coil. A north pole of the third magnet is located opposite the south pole of the second magnet and a south pole of the fourth magnet is located opposite the north pole of the first magnet. When electrical current is passed through the coil in one direction, the member is moved in a first direction, and when electrical current is passed through the coil in another direction, the member is moved in a second direction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.