| 摘要 |
PROBLEM TO BE SOLVED: To restrict the temperature of one or both electrodes without changing a bead glass by fixing an accelerating electrode to the bead glass, and supporting a control electrode through an insulating part different from the bead glass. SOLUTION: An accelerating electrode 4 is fixed to the bead glass 6, and a control electrode 3 is supported by the accelerating electrode 4 through an insulating part 8 different from the bead glass 6. A space more than three times of the diameter of an electron beam diameter control hole 31 is secured in the periphery of the control hole 31 of the insulating member 8 at a part near a passage for electron beam. With this structure, temperature of the control electrode 3 and the accelerating electrode 4 become equal to each other, and temperature can be lowered about 70 degree in comparison with a case where the control electrode 3 is directly supported by the bead glass 6. With this lowering of temperature, unnecessary emission of electron from the control electrode 3 can be restricted, and generation of luminescent spot on a phosphor screen due to the grid emission from the control electrode at a high ratio can be perfectly eliminated. Additional working of the bead glass is eliminated, and lowering of the strength of the bead glass 6 is eliminated.
|
