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:
Sep. 16, 2003
Filed:
Jun. 29, 2000
Eiji Yonezawa, Aichi, JP;
Nidek Co., Ltd., Aichi, JP;
Abstract
A defect inspecting apparatus for inspecting a defect of an object having a periodic pattern includes: a dark field illumination optical system that illuminates the object with substantially parallel illumination light in a direction having a predetermined first inclined angle relative to an inspection surface of the object; an imaging optical system having an imaging element for imaging the object illuminated with the illumination light, the imaging element having an imaging lens; and a defect detecting system for detecting the defect based on image data of the object thus imaged. A mutual positional relation ship between the direction of illumination by the illumination optical system and a direction of imaging by the imaging optical system is determined based on a diffraction angle defined by a period of the pattern and a wavelength of the illumination light. A sum of an aperture angle of the illumination light and an object side aperture angle of the imaging lens is set to be smaller than the diffraction angle.