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:
Oct. 22, 1991
Filed:
Nov. 08, 1988
Applicant:
Inventors:
Stuart T Spence, South Pasadena, CA (US);
Harry L Tarnoff, Van Nuys, CA (US);
Assignee:
3D Systems, Inc., Sylmar, CA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01J / ;
U.S. Cl.
CPC ...
356121 ; 356375 ; 356398 ; 425174 ; 264 22 ;
Abstract
An apparatus and a method for correcting for drift in production of objects by stereolithography is disclosed. A beam sensor comprising a pinhole in a plate and a photodector behind the pinhole is used to obtain the apparent position of the beam at calibration time and subsequently. A comparison between the prior and present apparent position of the sensor is made in order to determine a drift error correction term to be used to compensate for drift and thereby improve the accuracy and pointing repeatability of the scanning mechanism.