Method and apparatus for protecting a film gate against dirt while changing films
US4223985A · kind A · utility
2Cited by
3References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 10, 1978 |
| Grant date | Sep 23, 1980 |
| Priority date | — |
| Expiry date | Jul 10, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B1/48
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A film passing by an aperture of a film gate for purpose of projection or exposure is immersed in a liquid in order to minimize the effect of optical imperfections in or upon the film. When changing from one reel or roll of film to the next sufficient liquid is withdrawn so that the new film can be threaded into the film gate in a dry state; however, the interior glass surfaces of the gate are not permitted to become dry, but instead are continuously washed with liquid so as to prevent the accumulation of particulate matter or other foreign material that would tend to degrade the quality of the image.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.