| 摘要 |
PURPOSE: To shorten image output time by electron emission of a cathode ray tube by enhancing absorption of heat from a heater in a cathode structure which is of a type where a cathode substrate metal is fitted against the inner surface of a cathode sleeve, and by preventing heat loss by radiation. CONSTITUTION: This cathode ray tube has a vacuum envelope composed of a panel having a fluorescent screen, a neck storing an electron gun, and a funnel connecting the panel and the neck. The electron gun has a cathode 40 with a structure where a cathode substrate metal 41 is fitted with and held at one end of a cylindrical cathode sleeve 43 and where a heater insertion opening is formed at the other end. In this case, in the cathode 40, the diameter of the cylindrical cathode sleeve 43 is smaller at a part or all part of one end than at the other end and, in a heater 31, the diameter of a heating part wound in a coil form is smaller than that of a leg part and, when inserting the heater 31 into the cylindrical cathode sleeve 43, thermal efficiency is enhanced by tightly contacting a small diameter part of the cylindrical cathode sleeve 43 with the coil part of the heater 31. Heat loss by heat radiation is reduced by reducing the diameter of the cylindrical cathode sleeve 43 near an electron emissive material layer.
|
