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:
Sep. 29, 1998
Filed:
Feb. 14, 1997
Mitchell G Van Ochten, Livonia, MI (US);
Matthew P Frazer, Plymouth, MI (US);
Yongxing Wang, Novi, MI (US);
Medar, Inc., Farmington Hills, MI (US);
Abstract
A method and system are provided for measuring a two-dimensional deflection angle of a beam of light reflected from a disk having unknown radial and tangential tilt components by first generating reference data relating to known tilt of a reference disk and then processing the reference data with electrical signals from a two-dimensional photodetector to obtain values related to the deflection angle and the unknown radial and tangential tilt components. The photodetector is preferably a semiconductor photodiode having an active area which measures position of radiant energy in a spot of light focused in a detector plane by a focusing lens. A signal processor including a computer system programmed in accordance with a software algorithm compensates for interaction between X and Y axes of the active area of the photodiode to compensate for alignment errors or tolerances, not only up, down, left and right, but also for rotational errors as well. In this way, the method and system can utilize a single small, relatively low cost semiconductor photodiode for both radial and tangential measurements of the same spot of light.