GB1286231A - An electron multiplication target and an image pickup tube using the same - Google Patents

Abstract

1286231 Image pick-up tubes; targets TOKYO SHIBAURA ELECTRIC CO Ltd 2 Jan 1970 [7 Jan 1969 7 Feb 1969 2 April 1969] 180/70 Headings HID and H1K A target for an image vidicon type of tube comprising a semi-conductor substrate 40, Fig. 5, such as N-type silicon, containing a mosaic of opposite (P-type) conductivity regions 46, is characterized by the provision of an accelerating layer 45 for accelerating minority carriers produced by the impingement of the electron image. In Fig. 5, the layer 45 is an N<SP>+</SP>-type layer, and regions 47 of N-type conductivity are provided within each P-type region 46. The substrate may be coated with insulation (SiO 2 ) 43 except over the transistor areas, and the scanned side of the target may be covered with a 500 A thick antimony selenide film 44 to prevent unnecessary charging of the layer 43. The N-type regions 46 may be omitted (Fig. 4, not shown) to leave an array of diodes. In a modification of this diode array, Fig. 6 (not shown), the layer 45 is of metal such as aluminium or antimony having a smaller work function than the silicon substrate. If the conductivities were reversed, ie. the substrate had P-type conductivity, the metal would have a higher work function and could be tellurium, indium or platinum. In this example the film 44 is of antimony sulphide. The target is mounted in a camera tube with the layer 45 facing the photo-cathode, and if this layer is of metal it also acts as a light barrier and serves to protect the target from any caesium on the photo-cathode. An annular insulator (32, Fig. 2, not shown) spaces the target from an adjacent field mesh (16) and prevents light from leaking between the scanning and the image sections of the tube.