Photographic background device
US4183644A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 31, 1978 |
| Grant date | Jan 15, 1980 |
| Priority date | — |
| Expiry date | Mar 31, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B15/08
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A photographic background device enables a photographer to include a scene reproduced on a film transparency as background for photographed subjects. A transparency is illuminated while a beam splitter mirror directs light from the illuminated transparency to the camera lens, while allowing light from the subject to pass through the mirror to the camera lens. A movable lens system of positive power is provided to allow the transparency image to appear in focus at the lens. Vignetting is alleviated by locating a concave mirror on the side of the beam splitter opposite the side on which the movable lens system is located. In this manner, the illuminated film transparency image will pass through the beam splitter, be reflected by the concave mirror back to the beam splitter and be reflected from the beam splitter to the camera lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.