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:
Apr. 12, 1990
David R McMurtry, Wotton-Under-Edge, GB;
William F Stephens, Badminton, GB;
Renishaw plc, Gloucestershire, GB;
Abstract
Apparatus for generating a quadrature signal for the purpose of determining the direction in which the scale is being read. There is provided a primary grating means defining spaced lines and adapted for generating orders of diffraction, secondary grating means defining spaced lines arranged at an angle to those of the primary grating means thereby to separate said orders of diffraction into differing phases, and tertiary grating means movable together with the secondary grating means relative to said primary grating means and adapted for detecting the respective said phases and for generating correspondingly phased light modulations which are detected by respective transducers connected to a quadrature-forming circuit.