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:
Feb. 07, 1978
Filed:
Oct. 20, 1976
Canon Kabushiki Kaisha, Tokyo, JA;
Abstract
This disclosure describes an apparatus for interferometrically measuring the physical properties of test object in which a test object having at least two surfaces and a substantial thickness is illuminated by a source of broadband light beam, each of plural wave fronts then formed and having an optical path difference therebetween is split by the transmission of the light beam or by the reflection of the light beam thereby, the split wave fronts are superposed each other respectively to form broadband light interference fringes and the physical properties such as thickness and refractive index of the test object are measured from the broadband light interference fringes, and which is especially provided with means for forming broadband light interference fringe by superposing the split wave fronts tilted to each other, while forming an image of said test object in the position where said interference fringe is formed.