| 摘要 |
PURPOSE:To realize a high resolution without deteriorating the brightness and the resolution at the output fluorescent screen, by placing a screen electrode at the output face side from an anode, applying an acceleration voltage more than a specific voltage, and controlling the pontential of the screen electrode within a specific area. CONSTITUTION:Electrons flying a cathode 1 pass through focusing electrodes 2 and 3, and accelerated by applying a voltage of 35kV or more of an anode 4. The electrons accelerated by applying a voltage from 20-35keV at a screen electrode are decelerated between the anode 4 and the screen electrode 5 to reduce their energy to be optimum for the fluorescent screen, and then absorbed by the fluorescent screen 6 to illuminate the screen. When the electrons are accelerated, focused, and decelerated in such a way, they operate in expanding directions by an electron lens. However, since the distance between the anode and the screen electrode is small, the influence of the expansion is little, and, since the electrons are decelerated hardly to permeate the phosphors, the brightness is not reduced, and a high resolution rate is obtained.
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