| 摘要 |
PURPOSE:To obtain a picture with good color balance by controlling the voltage to be impressed on a control electrode which controls a focusing electrode, an electrostatic type deflection electrode and luminous strength of an electron beam while independently changing the electron beam diameter on the screen every electron beam. CONSTITUTION:With regard to display elements, a rear electrode 1, a wire cathode 2 serving as an electron beam supply, vertical focusing electrodes 3 and 3', a vertical deflection electrode 4, an electron beam stream control electrode 5, a horizontal focusing electrode 6, a horizontal deflection electrode 7, an electron beam acceleration electrode 8 and a screen plate 9 are arranged while being housed in the vacuum of a flat glass bulb. As for the screen 9, phosphor 20 is applied on the back of a glass plate 21 while a pair of phosphors of R, G and B are provided for every electron beam. A power supply circuit 22 impresses DC voltage on each electrode while a composite picture signal of a TV signal is applied to an input terminal 23. A synchronous signal is given to a vertical deflection driving circuit 27 and a horizontal deflection driving circuit 29. And the voltage giving a beam focusing condition from the circuits 22, 27 and 29 is controlled in order to set the electron beam diameter on the screen 9 to a constant value. |
