Microform readers
US4200366A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 28, 1977 |
| Grant date | Apr 29, 1980 |
| Priority date | — |
| Expiry date | Oct 28, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/115
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The invention provides a portable reader for reading, by way of a magnified image, microform material such as microfiche or microfilm. The reader has a support for the microform material and a light source to pass light through the material. A projection lens is provided to project an image of the material on to a screen and there is also a biocular magnifier lens through which an observer can view a magnified version of the image. A partial reflector is disposed in the light paths between the projection lens and the screen and between the screen and the biocular magnifier lens so that light travels from the projection lens to the screen via the partial reflector and from the screen to the biocular magnifier lens via the partial reflector. In a convenient arrangement light travelling from the projection lens is reflected by the partial reflector towards the screen, and light travelling from the screen is transmitted through the partial reflector to the biocular magnifier lens. On the other hand the arrangement may be reversed so that light from the projection lens is transmitted through the partial reflector to the screen while light from the screen is reflected by the partial refl…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.