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:
Jan. 30, 1996
Filed:
Oct. 12, 1994
Daniel Mansfield, Leicester, GB;
Ian Bell, Leicester, GB;
Ian Buehring, Leicester, GB;
Jennifer Harding, Leicester, GB;
Rank Taylor Hobson Limited, , GB;
Abstract
Apparatus for measuring surface roughness utilizes diffraction patterns derived from the surface under test. The energies in the different orders are detected and processed utilizing various different algorithms dependent upon a number of factors such as the number of orders in the diffraction pattern and asymmetry in the diffraction pattern. Various filter functions both for the diffraction pattern itself and for values of surface roughness after measurement are disclosed. One algorithm for measuring surface roughness involves comparison of values representing the energy orders with reference values, preferably reference values obtained by an interpolation operation between one set of reference values representative of a diffraction pattern from a symmetrical surface and another set representative of a diffraction pattern from an asymmetrical surface.