Electrostatically Scanned Image Orthicon

Abstract

This chapter presents experimental results for electrostatically scanned image orthicon. An investigation is carried out into the design of a small, high-performance image orthicon tube, using electrostatic scanning, which eliminates the large and heavy coil assemblies from an image orthicon camera. Although a vidicon has been developed using electrostatic scanning, this problem had not been undertaken for the image orthicon because of the difficulty of designing the electron optics of the scanning section that has to satisfy the following two precise criteria for the scanning of the electron beam: (1) the primary electron beam must land normally on the target and (2) the return beam must be directed into an electron multiplier. Since the successful reproduction of images with an all-electrostatic image orthicon, further improvements have taken place, which lead to the conclusion that the best combination is that of a short magnetic-focusing image section with an electrostatic scanning section. In this chapter, investigations into electrostatic low-beam-velocity scanning are described and test results of an experimental image orthicon tube are presented. Results show the usefulness of the all-electrostatic tube somewhat restricted, when excellent picture quality is needed, by limited resolution and distortion in the electrostatic image section.