GB972274A - Improvements in or relating to electron discharge devices - Google Patents

Abstract

972,274. Cathode-ray tubes. ELECTRIC & MUSICAL INDUSTRIES Ltd. Jan. 16, 1961 [Jan. 15, 1960], No. 1481/60. Heading H1D. An image intensifier comprises a photoemissive cathode 3, a double-sided charge storage target of partially conducting glass 4 having photo-emissive mosaic elements 5 deposited on the side nearest a luminescent screen 9, with a number of image intensifying electrodes 7 disposed between the target 4 and the screen 9. Focused by a coil 10, electrons from the cathode 3 are projected on to the target by ring electrodes 12, 13, 14, setting up a charge pattern on the target which when illuminated by a light source 17 causes the mosaic elements to emit photoelectrons in correspondence to the charge pattern, these being projected by ring electrodes 16 towards the image intensifying electrodes 7, and finally to the luminescent screen 9. The light source 17, which is also used to restore the target to an equilibrium potential, may be arranged to project straight on to the mosaic elements through a window provided in the envelope 1, and further image intensifying electrodes may be disposed between the cathode 3 and the target 4. The intensifying electrodes may comprise an insulating layer, e.g. of aluminium oxide, having a conducting layer of aluminium on one side and a photo-emissive layer of potassium chloride.