One time use camera uses magnetic micro-shutter as an exposure frame counter
US6295416A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 1999 |
| Grant date | Sep 25, 2001 |
| Priority date | — |
| Expiry date | Nov 30, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B26/02
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A novel exposure frame counter is disclosed that gives the appearance of more expensive LCD type displays while not requiring the support electronics and has the ability to erase itself after being used. A disc of low permeable magnetic material has exposure frame numbers recorded into the material in a selected manner so as to create a desired magnetic field. A magnetic micro-shutter is used to create the exposure frame numbers by placing individual micro-shutters over the disc which react to the magnetic field of the disc to form numerals that indicate the exposure frame the camera is on. When the camera is advanced, the section of the disc that was indicating the exposure frame advances to the next frame and the previous frame passes across a field created by a strong permanent magnet and is erased by the permanent magnet. The magnetic micro-shutters of the exposure frame counter are formed essentially as a seven-segment display to form the numerals of the exposure frame counter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.