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:
Dec. 18, 1990
Filed:
May. 01, 1989
Yoshinori Bessho, Mie, JP;
Brother Kogyo Kabushiki Kaisha, Aichi, JP;
Abstract
An apparatus for optically measuring the roughness of a surface of a subject in a non-contacting manner, based on a heterodyne interference wherein a phase of a beat beam produced by a reference laser beam, and a measuring laser beam reflected by the surface of the subject and having a wavelength different from that of the reference laser beam is changed with a change in the length of an optical path of the measuring laser beam, which occurs due to a change in the surface roughness of the subject. The apparatus includes a laser source for producing the reference and measuring laser beams, a lens device having an object lens for converging the measuring laser beam on the subject surface, and a deflector for deflecting the measuring laser beam before the measuring laser beam is incident upon the subject surface, whereby the point of convergence of the measuring laser beam is moved on the subject surface in a direction parallel to the surface, while the subject is held stationary.