Aligner detector including an electrooptic modulator for each diffraction order
US6049383A · kind A · utility
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2References
12Claims
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Key dates
| Filing date | Nov 13, 1998 |
| Grant date | Apr 11, 2000 |
| Priority date | — |
| Expiry date | Nov 13, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/272
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An improved aligner detector is provided. The improved aligner detector includes, a detector, several electrooptic modulators, and a refractor set, which includes several wedge patterns. Each of the electrooptic modulators includes a double-refraction transistor, which has a property of double refraction. By applying a special voltage on the double-refraction transistors, the double-refraction transistors can become transparent or opaque. Thereby, the electrooptic modulators can select a desired order of the diffraction light ray. The selected diffraction light ray is refracted by the refractor set to the detector for analysis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.