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:
Nov. 29, 1988
Filed:
Nov. 26, 1986
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A device, usable with an object having a layer, for measuring the thickness of the layer, includes a system for irradiating the object with light while changing its wavelength, the irradiating system having a light-emitting portion disposed opposed to the surface of the object, a photodetecting unit for detecting the light from the object irradiated by the irradiating system, the photodetecting unit having a light-receiving portion disposed opposed to the object, a system for detecting the thickness of the layer of the object on the basis of the detection by the photo-detecting unit, and a setting mechanism for positioning the object, relative to the light-emitting portion and the light-receiving portion, at a distance that substantially corresponds to an extremum of the quantity of light which is to be received by the light-receiving portion and which is variable with the positional relation of the object with the light-emitting portion and the light-receiving portion.