Process and assembly for non-destructive surface inspections
December 20, 2016. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesDefect detection system Scanning contaminant and defect detector Method for determining the quality of light scattering material Method and apparatus for inspecting specimen surface Reflection densitometer with ellipsoid reflection surface System for checking defects on a flat surface of an object Radiant energy reradiating flow cell system and method Method for determining the phase of phase transformable light scattering material Apparatus and method for detecting defects and dust on a patterned surface Method and apparatus for determining the volume & index of refraction of particles InventorsAssigneeApplicationNo. 770491 filed on 12/20/1996US Classes:356/237.3Detection of object or particle on surfaceExaminersPrimary: Rosenberger, Richard A.Attorney, Agent or FirmForeign Patent References
International ClassG01N 021/88AbstractA light beam is directed towards a surface along a direction normal to the surface. The surface is caused to move so that the beam scans the surface along a spiral path. An ellipsoidal mirror is placed with its axis along the surface normal to collect light scattered by the surface and any anomalies at the surface at collection angles away from the surface normal. In some applications, a lens arrangement with its axis along the surface normal is also used to collect the light scattered by the surface and any anomalies. The light scattered by the mirror and lenses may be directed to the same or different detectors. Preferably light scattered by the surface within a first range of collection angles from the axis is detected by a first detector and light scattered by the surface within a second range of collection angles from the axis is detected by a second detector. The two ranges of collection angles are different, with one detector optimized to detect scattering from large particles and defects and the other detector optimized to detect light from small particles and defects.Other References
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