Optics: measuring and testing – By configuration comparison – With comparison to master – desired shape – or reference voltage
Patent
1987-05-11
1989-05-16
Rosenberger, Richard A.
Optics: measuring and testing
By configuration comparison
With comparison to master, desired shape, or reference voltage
382 8, G01K 900
Patent
active
048304972
ABSTRACT:
An improved pattern inspection system for automatically inspecting patterns on a printed circuit board, a semiconductor chip, etc. The pattern inspection system includes an optical sensor, a binary conversion circuit, a memory storing binary converted data in a matrix form, a length measurement circuit, a reference circuit and a determination circuit. The length measurement circuit includes a gate unit for picking-up the binary converted data array from the memory in radial directions with respect to an origin and for a predetermined length in each direction, a unit for measuring radii of the pattern in the radial directions from the origin in response to the picked-up binary converted data, a unit for determining a center line of the pattern in the picked-up binary converted data array by the measured length of the first directions, and a unit for encoding the measured length of the second directions to numerals each corresponding to one length of each of the second directions. The reference circuit receives the coded numerals for a reference pattern and forms a coded reference in response to the coded numerals. The determination circuit receives coded numerals for a inspection pattern, compares a code in response to the received coded numerals with the coded reference in the reference circuit, and determines a fault in the inspection pattern.
REFERENCES:
patent: 4500202 (1985-02-01), Smyth
Ando Moritoshi
Iwata Satoshi
Fujitsu Limited
Rosenberger Richard A.
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