| 摘要 |
PURPOSE:To obtain an extreme-magnification wide-visual field reflection electron image with uniform brightness by providing a means to compensate a change of the average level of output signals due to the scanning of electron rays. CONSTITUTION:A magnification control signal directing the magnification variable circuit 4, and a scanning signal from a scanning signal generating circuit 3 is fed to a deflection coil 2 after being converted into a large-amplitude signal. An arithmetic circuit 5 generates an output by adding output signals of all detection elements Dmn. At the same time, the control signal from the control section 6 is also fed to a switching circuit 9, which is made a conductive state, and the correction signal from a correction signal generating circuit 8 is fed to an intensity correcting circuit 7. The correction signal generating circuit 8 generates a correction signal compensating a decrease of the average level of the outputs of an adding circuit due to a decrease of the solid angle based on the scanning signal from the scanning signal generating circuit 3. Accordingly, an extreme-magnification wide-visual field reflection electron image with uniform brightness can be displayed on a CRT10. |
