GB450973A - Improvements in or relating to cathode-ray tubes - Google Patents

Abstract

450,973. Cathode-ray tubes. FERNSEH AKT.-GES., Goerzallee, Zehlendorf, Berlin. Jan. 25, 1935, No. 2529. Convention date, Jan. 26, 1934. [Class 39 (i)] The electron beam of a television &c. tube is modulated in intensity and deflected and is then focused on to the fluorescent screen by an electrostatic lens of two or more apertured diaphragms charged to accelerate the electrons. The cathode or an aperture in a diaphragm is focused on to the fluorescent screen and in the latter case a large indirectly heated cathode may be used. A lens of two diaphragms may be placed between the two pairs of deflecting plates or on the side of the plates remote from the cathode ; the first diaphragm is then connected to a screen surrounding the plates and to the anode of the electron gun and the second diaphragm is at a higher positive potential and connected to the fluorescent screen. In a modification, the beam formed bv the cathode 11 and anode 13 is modulated by an electrode 12 forming an extension of the cathode surface. An aperture in a diaphragm 14 is focused by a retarding lens 15, 16 on to a small rectangular aperture 18<1> in a screen 18. The ray is deflected by plates 23, 24 to form an " electron image " in the aperture 181 and this image is projected on to the fluorescent screen 22 by diaphragms 19, 20 forming an accelerating lens. Screens 17, 21 are connected to the diaphragms 19, 20.