| 摘要 |
PURPOSE: An electron gun for cathode ray tube is provided to improve quality of focus of a cathode ray tube by using an electrode for controlling a vertical focusing degree. CONSTITUTION: An electron gun(6) is formed with a cathode(18) for emitting thermions, a control electrode(20) and a screen electrode(22) for focusing the emitted thermions to form electron beam, a focus electrode(24) and an anode electrode(26) for focusing and accelerating the electron beam, and a support body for aligning the cathode(18) and a multitude of electrodes. The cathode(18) emits the thermions by using a heater mounted in the cathode(18). The cathode(18) controls current density by controlling electric potential of the control electrode(20). The focus electrode(24) is formed with the first electrode having an electron beam passing hole and the second electrode having three electron beam passing holes. The third electrode is formed in an inside of the second electrode to extend a vertical focusing region of the electron beam.
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