Microfiche reader assembly and method
US4334742A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 4, 1980 |
| Grant date | Jun 15, 1982 |
| Priority date | — |
| Expiry date | Mar 4, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/115
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A microfiche reader assembly for optically projecting a microfiche image on the backside of a screen for viewing from its front side is disclosed herein. This assembly includes a housing having an inner chamber, a projection screen supported by the housing and a support for the microfiche itself. A beam of light is passed through the microfiche along an incoming path and into the chamber where a plurality of light reflecting surfaces are utilized to redirect the same beam onto the backside of the screen along a plurality of different paths including a final path incident with the screen and at least one intermediate path between the incoming and incident paths. These paths are specifically selected to improve image contrast and corner image brightness at the screen and to provide a relatively long overall path length at a small field angle while minimizing the size of assembly housing necessary to contain the previously recited light reflecting surfaces.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.