Deflecting spherical lens

An electrostatic spherical lens that permits both x- and y-deflection has been developed. The spherical field is formed within a conical surface by dc voltages applied to a series of resistive rings painted on the interior of the envelope. Deflection is accomplished by ac voltage drops around the rings which superimpose a deflection field upon the spherical field. To study the lens, an image intensifier was built. The deflection sensitivity is approximately 500 volts per inch. Over 2 inches of the 5-inch photocathode is usable; beyond this diameter a slight pincushion distortion is noticeable. The diameter of the circle of confusion at the crossover point is approximately ¼ inch. The natural focal length of the lens-aperture combination is 18 inches and can be adjusted to 14 inches by varying the post-acceleration voltage. The techniques for forming the lens, the electron optics, and the performance of the tube are described. The role of this lens in a fast camera application for the display of sequential images is also discussed.