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. 12, 1991
Filed:
Mar. 02, 1990
Applicant:
Inventors:
Assignee:
Other;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
2502 / ; 2502 / ; 356 / ;
Abstract
A method and apparatus for measuring a rotation angle. At least one rotatable optical grating is provided to be pivotal on a rotation axis relative to one or more slits parallel to the rotatable optical grating. The rotatable optical grating is radial to the rotation axis. To measure a rotation angle the rotatable optical grating is pivoted relative to at least one stationary optical grating which is radial to a center opposite to a center of the rotatable optical grating. An overlap area is defined between the two optical gratings and measurement of the relative movement between the rotatable optical grating and the stationary optical grating is detected by at least one photoelectric receiver.