| 摘要 |
An apparatus for automatic position alignment consists of two pairs of deflectors(23X, Y)disposed perpendicularly to each other along the pathway of the electron beam; two pairs of electrodes(5-8) disposed face to face; power sources(21,22) of the deflectors, controlled by the signal from the electrodes; and a differential amplifier(19,20) providing the signal to the power sources. This signal is compared with the ratio of the detected signal and the output reference signal.
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