Film cassette
US4894673A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 12, 1989 |
| Grant date | Jan 16, 1990 |
| Priority date | — |
| Expiry date | Jan 12, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S242/912
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In a film cassette, an "exposure-completed" indicator is positioned within a film passage slit to the outside of the cassette shell to be normally covered by the filmstrip. The indicator is uncovered by the filmstrip only when a leader section of the filmstrip is wound through the film passage slit further into the cassette shell, after the filmstrip is completely exposed in a camera. A window is provided in the cassette shell to view the indicator whenever it is uncovered by the filmstrip. This feature is useful to prevent double exposure of the filmstrip, by informing the photographer that the filmstrip should not be re-used in the camera.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.