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:
Jun. 26, 1984
Filed:
Jan. 25, 1982
George W Cann, Lagrangeville, NY (US);
Donald E Davis, Wappingers Falls, NY (US);
Ralph R Trotter, Hopewell Junction, NY (US);
IBM Corporation, Hopewell Junction, NY (US);
Abstract
An X-Y positioning system for electron beam lithography employs an adaptive drive system for feedback control. A gradually increasing drive voltage, superimposed upon a step wave, is summed with the position error signal to achieve position within the system deadband zone. The drive voltage, while superimposed upon the error voltage, increases until mechanical friction and drift in the deadband zone are overcome. A function generator alters the error signal such that the combined error signal and drive voltage cause the system to approach the null point minimizing servo oscillations. A limit circuit determines when the system has reached a set of inner limits and generates an operative output signal to the signal controller which continues until the position exceeds a second, outer set of limits.