Pattern testing apparatus
US4472738A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 24, 1982 |
| Grant date | Sep 18, 1984 |
| Priority date | — |
| Expiry date | May 24, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30148
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A pattern defect testing apparatus comprises a first detection circuit which defines a first detection area on a two-dimensional pattern and produces a first detection signal when all digital signals representative of densities of picture cells in the first detection area have the same logical value, a second detection circuit which defines a second detection area on the two-dimensional pattern and produces a second detection signal when at least one of digital signals representative of densities of picture cells in the second detection area has a logical value different from that of the digital signals to the first detection circuit, and a discriminating circuit for discriminating the presence of a defect in the second detection area when the first and second detection signals are produced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.