| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection type cold cathode ray tube device wherein resolution on the circumference of a screen is enhanced. SOLUTION: An electron gun is composed of a cathode, a first electrode G1, a second electrode G2, a focus electrode, and an anode electrode G5. The focus electrode is divided into a first group of focus electrodes comprising the third electrode G3 and a first fourth electrode G4A along the tube axis and a second group of focus electrodes comprising a second fourth electrode G4B and the anode electrode C5, and a quadrupole lens is formed between the first fourth electrode G4A and the second fourth electrode G4B forming counter electrodes of both groups of the focus electrodes. A first focus voltage (Vf1 + dVf1) in which a first dynamic dVf1 increasing by synchronizing with the increase of an amount of deflection is superposed over a first fixed focus voltage Vf1 is impressed on the first fourth electrode G4A composing the first group of the focus electrodes, and a second focus voltage (Vf2 + dVf2) in which a second dynamic dVF2 increasing by synchronizing with increase of an amount of deflection is superposed over a second fixed focus voltage Vf2 is impressed on the second fourth electrode G4B composing the second group of the focus electrodes. COPYRIGHT: (C)2006,JPO&NCIPI
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