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:
Jun. 30, 1998
Filed:
Jan. 11, 1996
Hiroshi Tanaka, Utsunomiya, JP;
Michio Kohno, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An inspection apparatus and method includes an illuminator for projecting a light beam onto a substrate having a predetermined pattern formed thereon and a sensor for sensing light from the substrate and photoelectrically converting the light to an electrical signal. The electrical signal has a pattern signal component representing light from the predetermined pattern and a foreign matter signal component representing light from foreign matter on the substrate in the event foreign matter is on the substrate and is sensed by the sensor. The apparatus also includes a converter for converting the electrical signal output by the sensor into a digital signal having a pattern signal component and a foreign matter signal omponent in the event the electrical signal output by the sensor has a foreign matter signal component. The apparatus also includes a processor for performing calculation processing on the digital signal for discriminating the digital foreign matter signal component from the digital pattern signal component in the event the digital signal has a foreign matter signal component.