Telecentric variable power illumination system
US4511223A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 14, 1982 |
| Grant date | Apr 16, 1985 |
| Priority date | — |
| Expiry date | Jun 14, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B21/08
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A variable power telecentric illumination system comprises a first converging lens group, a second converging lens group, a third diverging lens group and a fourth converging lens group arranged in this ordinal sequence as viewed in the direction toward the object side to be illuminated from the light source side. The second and third groups are interchangeable in position. An image of the light source by the composite system of the first and second groups is formed between the second and the third groups. The focal point on the light source side of the composite system of the third and fourth groups is coincident with the light source image. When the positions of the second and third groups are interchanged, the composite system of the first and third groups forms an image of the light source between the second and third groups. The focal point on the light source side of the composite system of the second and fourth groups is coincident with the light source image. The illuminated area on the object surface is changed by the interchange of positions between the second and third groups while maintaining the condition of telecentric illumination.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.