Automatic system and method for inspecting hole quality
US4555798A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 20, 1983 |
| Grant date | Nov 26, 1985 |
| Priority date | — |
| Expiry date | Jun 20, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30148
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An automatic inspection system for inspecting holes in a mask including carriage means 30, illumination means 44, optical means 48, photosensitive detector means 46, and signal processing means 56. The mask 34 to be inspected is positioned by the carriage means in a horizontal plane. The optical means projects a focused image of a portion of the mask onto the photosensitive detector means. Photodiodes in the detector means are responsive to light from the illumination means that is transmitted through the holes in the mask. The signal processing means scans the outputs of the photodiodes and stores in memory a digital representation of the mask. The signal processing means performs inspection measurements and comparison tests. A smoothness checker circuit 240 measures the local radius of curvature of each hole at several places and compares the measurements to predetermined curvature limits to detect nicks and sharp protrusion defects. An area check circuit 246 measures the area of the hole and compares it to predetermined area limits. A diameter check circuit 244 measures the diameter of the hole in two dimensions and compares it to predetermined diameter limits. If either the hol…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.