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. 26, 2000
Filed:
Jan. 08, 1999
Other;
Abstract
A system for measuring the distance of an examined surface from a reference plane includes two detectors and a radiation source for directing a beam along a path which includes a first focussing lens for focussing the beam as a spot on the surface and reflecting it. A collecting lens converts the reflected radiation to a reflected beam. A splitter directs part of the reflected beam through a second path which includes a second focussing lens for focussing part of the reflected beam onto a surface of the first detector. Its position on the first detector corresponds to the distance of the examined surface under the spot from the reference plane, according to by a first equation with two terms: a first drawback error and a first surface displacement. The other part of the reflected beam propagates through a splitter and along a third path which includes a third focussing lens for focussing the other part of the reflected beam onto a second spot on a surface of the second detector. Its position on the second detector corresponds to the distance of the examined surface from the reference plane according to a second equation with two terms: a second drawback error and a second surface displacement. The second and third focussing lenses cause the first and second equations to be independent. A processing unit utilizes the outputs of the detectors to measure the distance of the examined surface from the reference plane.