Illuminating apparatus and projection exposure apparatus provided with such an illuminating apparatus
US5296892A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 22, 1993 |
| Grant date | Mar 22, 1994 |
| Priority date | — |
| Expiry date | Jan 22, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B19/0047
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An illuminating apparatus comprises a first optical integrator and a second optical integrator which are replaceably arranged. The second optical integrator is structured to provide substantially the same number of secondary light sources as the first optical integrator but with the different size of surface light source formed by these second light sources. Further, the structure is arranged so that it has an aperture number on the emission side, which is equal to the aperture number of the first optical integrator on its emission side. Hence, the illuminance evenness is not degraded even when the .sigma. value is significantly varied.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.