| 摘要 |
PROBLEM TO BE SOLVED: To provide a cathode-ray tube device capable of forming beam spots of uniform shape on the whole surface of a phosphor screen by reducing the horizontal diameter of the beam spot at the peripheral part of the phosphor screen. SOLUTION: An electron beam structure 7 is provided with an auxiliary lens for pre-focusing electron beams, and a main lens for focusing the electron beams on the phosphor screen. The main lens is formed of a second segment G5-2, a first addition electrode GM1, a second addition electrode GM2 and a sixth grid G6 arranged in order along the proceeding direction of the electron beams. The electron gun structure 7 is provided with a means for enlarging the lens bore of the main lens with the increase of deflection amount of the electron beams, and a means for lowering the focusing force of the auxiliary lens formed of a third grid G3, a fourth grid and a first segment G5-1, with the increase of the deflection amount of the electron beams.
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