Microform reader
US4050799A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 31, 1975 |
| Grant date | Sep 27, 1977 |
| Priority date | — |
| Expiry date | Mar 31, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/11
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The disclosure relates to a microform reader apparatus of the type which projects a magnified image of an image film frame onto the rear side of a viewing screen to facilitate forward viewing of the magnified image. The microform reader of the present invention includes an adjustable mirror assembly positioned between a light source and condensing lens for optimizing the brightness of the displayed image. In a preferred form the mirror assembly is adjustable from the front of the microform reader to allow simultaneous monitoring of the brightness of the display while the adjustment is being made. The microform reader of the present invention also includes an adjustable lens assembly which allows the optical axis of the lens assembly to be adjusted for perpendicularity to the image frame surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.