ELECTRON OPTICS FOR A MINIFYING IMAGE TUBE

摘要

A minifying image tube, such as an X-ray converter or image intensifier tube, is disclosed employing a curved photocathode for converting a photon image into an electron image. A flat image converter screen is provided for converting the minified electron image into an optical output image. An electrode structure is disposed between the photocathode and the flat converter screen for accelerating and focusing the electron image upon the converter screen. The electrode structure includes a plurality of coaxially aligned axially spaced cylindrical electrodes of decreasing diameter taken in the direction from the photoemitter toward the converter screen. The final or anode electrode projects into a constricted electron exit aperture in the next preceding electrode structure in order to shape the equipotentials at the entrance of the anode such as to obtain uniform resolution of the electrode image focused upon the flat converter screen over substantially the entire area of the converter screen.