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:
Mar. 24, 1981
Filed:
Dec. 01, 1976
Applicant:
Inventors:
Donald T Hurle, Malvern, GB;
Gordon C Joyce, Malvern, GB;
Assignee:
National Research Development Corporation, London, GB;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C30B / ;
U.S. Cl.
CPC ...
422109 ; 156601 ; 422249 ;
Abstract
In crystal growing apparatus in which a crystal is vertically pulled from an electric heated melt the weight of the crystal is measured by a load cell whose output is compared with an expected function to form a control loop for controlling heater power, the improvement comprises a correction circuit for applying to the control loop a signal compensating for a time differential (.lambda.a) of an error signal in the load cell output. The correction circuit may be a feedback or a feed forward loop.