Electric lamp and discharge devices: systems – Cathode ray tube circuits – Cathode-ray deflections circuits
Patent
1992-07-16
1995-02-14
Issing, Gregory C.
Electric lamp and discharge devices: systems
Cathode ray tube circuits
Cathode-ray deflections circuits
250396ML, 250398, G09G 104, G21K 108, H01J 314
Patent
active
053898583
ABSTRACT:
The magnetic axis of a stigmation yoke is varied from the mechanical axis of the stigmation yoke by differentially driving pairs of coils in a quadrupole configuration with currents which differ from a nominal stigmation current by approximately equal amounts, applied in opposite senses. Set-up procedures for electron beam deflection systems, such as in e-beam tools, are automated by emulating manual procedures in combination with electrical alteration of the magnetic axis of the stigmator yoke. Stigmation errors can also be corrected under automated set-up procedure control to allow dynamic correction of astigmatism in electron beam deflection system. Electrically variability of the magnetic axis of the stigmator yoke also allows the placement of the stigmator yoke at a position in the electron optical column other than prior to deflection stages as well as improved freedom from positional and aberrational errors.
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Langner Guenther O.
Petric Paul F.
International Business Machines - Corporation
Issing Gregory C.
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