The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 08, 1994
Filed:
May. 24, 1991
Hitachi, Ltd., Tokyo, JP;
Abstract
A defect inspection method and apparatus detect a defect which exists on the surface of a protection layer or a defect which exists in the protection layer and scatters the light on its surface, through the detection of the light which is derived from an illumination light and reflected on the protection layer surface and the light which is derived from a slit-formed illumination light and scattered in the area between the position where the light is incident to the transparent protection layer and the position where the surface of an element underneath the transparent protection layer is illuminated. An image process, which images two elements having the same appearance and compares the images, thereby to reduce inconsistent components emerging in portions other than a defective portion, is conducted through imaging under the bright field illumination and bright/dark field combined illumination, and the images are rendered the minimum filtering process based on 3-by-3 pixels and the defect judgement process based on comparison.