Illuminating device for photographic copying apparatus
US4371258A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 21, 1981 |
| Grant date | Feb 1, 1983 |
| Priority date | — |
| Expiry date | Aug 21, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B27/547
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An illuminating system has as main components: a light source comprising four low voltage lamps and, associated therewith, reflectors and condenser lenses, a filter unit, an image-producing pair of lenses, a deflecting mirror and light-mixing element made of glass. The condenser lenses produce images of the coils of the low voltage lamps in the central horizontal plane of the filter unit. Images of the condenser lenses are produced by the image-producing lens pair in a light entry face of the light-mixing element. This light entry face is provided with ribbings constituting cylindrical lenses of special dimensioning which effect homogenization of the light in the light-mixing element. In order to reduce light losses, the light-mixing element is composed of two frusto pyramidal element parts and has its smallest cross-sectional area in a middle region in which the smaller end faces of the frusto pyramidal parts are joined to an interposed diffusor disc. The filter unit comprises a pair of interference filters for each filter color. The filters of each pair can be driven by means of a stepping motor and cam disc to move symmetrically with regard to the optical axis. The illuminating …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.