| 摘要 |
<p>1,206,267. Cathode ray tubes. STROMBERG DATA GRAPHIX Inc. 25 April, 1969 [29 April, 1968], No. 21171/69. Heading H1D. A character display tube wherein an electron beam is shaped by a stencil 18 into a multiplicity of characters of which one is selected for display by the combination of deflection means 35-37 and a diaphragm 33 adapted to pass only one character, the selected character being directed to a required part of the screen 12 by deflection means 39, is provided with an electron lens arrangement 19 of variable magnification. In Fig. 1 there are two lenses formed by electrodes 21 and 22 which cooperate with electrode 16 and a wall anode 40 respectively. If both lenses are adapted for focusing the image the magnification may be variable between 3À6 and 23À2; the ganged switches 23 and 24 are adapted to energize the lenses to potentials which are found experimentally to produce correct focusing at required magnifications. In an alternative mode of operation an intermediate image is formed so that the two lenses operate in cascade, and the magnification can be varied between 26 and 37. In a modified lens arrangement (Fig. 3, not shown) a cylindrical electrode (58) connected to electrode 16 is arranged between the two lens electrodes 21 and 22.</p> |
