GB1063063A - Improvements relating to radiation sensitive devices - Google Patents

Abstract

1,063,063. Television pick-up tubes; photoconductive elements. ELECTRIC & MUSICAL INDUSTRIES Ltd. Nov. 18, 1963 [Nov. 24, 1962], No. 44531/62. Headings H1D and H1K. A target for a television pick-up tube comprises a conductive layer, a solid layer including photo-conductive antimony selenide, and a spongy layer including photo-conductive antimony selenide in that order. In a preferred arrangement the solid layer is antimony selenide and the spongy layer a mixture of antimony selenide and antimony trisulphide which may be overlain by a further solid layer of a similar mixture. A typical target is formed in situ in the tube. After sealing the end via a metal ring 4 (Fig. 1) the end is heated and an electrode formed by spraying on a tin salt solution. Then the tube is baked and degassed and material evaporated from boat 20 containing a mixture of antimony selenide and trisulphide in the weight ratio 4: 3 or 4:1 first in high vacuum to form the solid layer and then in argon, xenon, nitrogen or argon to produce the spongy layer. During the process material is deposited on grid 15 and shield 16 and a final solid layer may be formed by re-evaporating this in high vacuum by eddy current heating of these parts. As an alternative the layers are formed on the sealing member 3 in a demountable vessel before it is attached to the pick-up tube. In modifications of the above method, antimony selenide may be used alone, or selenium, cadmium sulphide or cadmium selenide included instead of antimony trisulphide.