| 摘要 |
PURPOSE:To obtain an electron ray device for observing an electron channeling pattern in which images with high resolution can be easily displayed by automatically causing the point on which electron rays are focused to coincide with the front focus surface of the objective. CONSTITUTION:Electron rays (EB) are focused by a first and a second focusing lens 2 and 3 before being deflected by a deflecting coil 5 and then become incident upon a crystalline sample 7 after passing through an objective 6. Then, secondary electrons produced from the sample 7 are detected by a detector 14. The excitation current of the focusing lens 3 is charged by an operation controller 12 and every change in image contrast accompanying the change in the excitation current is compensated by an automatic contrast-compensating circuit 19. In addition, output signals of the detector 14 produced accompanying electron ray scanning are monitored to detect the excitation current of the lens 3 for the maximum steep of the concave or convex of the output signals and then the current level is fixed at the thus determined level by a peak hold circuit 21. Accordingly, focusing for producing images with high resolution can be performed easily in a short time. |
