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:
Apr. 19, 1983
Filed:
Sep. 04, 1980
Reinhold Schmitt, Berlin, DE;
Siemens Aktiengesellschaft, Berlin & Munich, DE;
Abstract
In an exemplary embodiment, a command value signal is supplied to a magnetic deflection control loop which operates based on measurement of deflection coil current. A signal proportional to the rate of change of deflection magnetic field is supplied to one input of a differential amplifier, and a signal in accordance with the rate of change of the command value signal is connected with a second input of the differential amplifier. Any error between the rate of change signals as sensed by the differential amplifier is used as an auxiliary control of the deflection magnetic field, whereby eddy current influences are overcome. The system is particularly useful for precision control of an electron beam writer in the manufacture of semiconductor integrated circuits.