Field frame changeover mechanism for viewfinder
US5875364A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1997 |
| Grant date | Feb 23, 1999 |
| Priority date | — |
| Expiry date | Aug 26, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B19/12
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A field frame changeover mechanism suitable for a single-lens reflex camera, which allows clear confirmation of the photo range without increasing the size of the camera. The mechanism has darkening plates movable between a darkening position where the plates cover a part of the focusing screen and an open position where the focusing screen is uncovered by the plates. When the mirror which reflects the light transmitted from the photo-taking lens of the camera to the optical system of the viewfinder of the camera moves from an observation position located in the path of light transmitted through the photo-taking lens to a photo-taking position, the darkening plates retract from the locus of the mirror's movement in a correlated manner.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.