Illumination tailoring system using photochromic filter
US5614990A · kind A · utility
20Cited by
9References
31Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1994 |
| Grant date | Mar 25, 1997 |
| Priority date | — |
| Expiry date | Aug 31, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F2203/52
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Photochromic glass is situated between a light source for exposing resist coated on a wafer and the wafer. The photochromic glass is activated by a wavelength different from that which activates the resist. An array of individual light sources, each of varying intensity, provide activation light to the photochromic glass. A CCD array temporarily in the imaging plane measures light intensity distribution. A controller varies the individual light source array intensities to activate the photochromic glass to varying degrees to produce a desired effect at the imaging plane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.