Back lighting illumination system
US6003992A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 1998 |
| Grant date | Dec 21, 1999 |
| Priority date | — |
| Expiry date | Jun 2, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/0073
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A back light illumination system for providing substantially uniform illumination to a surface of an object to be observed so that the object may be accurately perceived by a machine vision system. The back light illumination system includes a light transmissive element having a central light transmissive portion and an opaque perimeter portion. A diffuser is located to cover the entire light transmissive portion and a rear surface of the diffuser is provided with a transmissive right angle film. A pair of opposed light sources are provided for illuminating a rear surface of the transmissive right angle film to supply light to the diffuser which uniformly diffuses the light and provides lighting of a substantially equal intensity and character to the light transmissive portion of the light transmissive element so that the back light illumination system thereafter emits substantially uniform illumination. The light supplied from the light sources to the right angle film is generally supplied at a shallow angle of between 0.degree. and 20.degree..
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.