| 摘要 |
PURPOSE:To project largely images on the screen of CRT by generating small spot images in the central part of the CRT viewing surface, applying lower voltage than the operating voltage to the anode and same voltage as the operating voltage to each of other electrodes. CONSTITUTION:The same voltage as the operating voltage is applied to the heater electrode 2, the cathode electrode 4, the first grid electrode 7, the second grid electrode 8, and the focus electrode 10, respectively. Applying slightly lower voltage than the operating voltage to the anode 12, so as to be able to generate small spot images in the central part of the CRT viewing surface, narrow width pulses are provided by the pulse generator 6. Due to the fact that the voltage applied to the anode electrode 1 when testing is set lower by 2.5kV from the usual operating voltage, the electron gun 16 results in converging at the position neighbouring the electron gun 16 rather than the screen surface, so the image 17 of electron emission surface of the cathode 4 can be projected largely on the CRT viewing surface 15. |
