AXIAL DEVIATION INSPECTING DEVICE

• Main Authors: SAOTOME NOBUYUKI, KASAHARA NORIKO
• Format: Patent
• Language: English
• Published: 22.06.1999
• Edition: 6
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PHYSICS; TESTING

PROBLEM TO BE SOLVED: To precisely detect the axial deviation for a matter to be measured whose axial deviation causes a trouble such as electron gun by emitting a converged electron beam flux to the matter to be measured and detecting the axial deviation from the image by the absorbed electron current quantity. SOLUTION: Electrodes G1, G2 of an electron gun are electrically insulated to each other, and the electrode G2 functions as the mask of electron beam to the electrode G1. Therefore, in scanning by electron beams having diameters larger than the hole part G2a of the electrode G2, only the electron beams within the diameter of the hole part G2a of the electrode G2 reach the electrode G1. Thus, the absorbed state of electrons in the electrode G1 are visualized to observe the display images of absorbed current images CP1, CP2, whereby the relative positional relation between both the electrodes can be judged. Since the relation of pore diameter size between the electrodes G1, G2 is G2a>=G1a, the absorbed current image is observed in a doughnut form when no axial deviation is present between the electrodes G1, G2, and a crescent form when the axial deviation is present, and the axial deviation can be provided by such as image processing.