Shutter driving apparatus
US4720726A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1986 |
| Grant date | Jan 19, 1988 |
| Priority date | — |
| Expiry date | Oct 28, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B9/14
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A shutter driving apparatus drives a programmed shutter with a stepping motor, by using a driving current pulse whose waveform has a leading half that gradually increases in amplitude and a trailing half having an amplitude smaller than the peak value of the pulse. At each rotary stage of the stepping motor, a smooth starting operation can be ensured without any adverse inertial effect at the start or end of rotation, the stepping motor being temporarily driven at low speed at the end of each pulse. In the case of an aperture priority exposure control using a programmed shutter, disadvantageous ripple motion of the shutter sectors is eliminated, thus enabling high precision exposure control.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.