| 摘要 |
PURPOSE:To make it possible to decrease concentration sensitivities of three electron beams against a fluctuation of focus voltage, or to maintain the concentration constant, by making the centers of cylindrical sinkings formed at the focus electrode enclosed face opposing to the G2 electrode eccentric to the opening centers at their top ends. CONSTITUTION:At the enclosed surface of the G3 electrode 24a opposing to the G2 electrode 13, three openings 24R, 24G, and 24B, with the centers on the parallel axes 20R, 20G, and 20B, keeping an equal interval S0, are formed into three engraved cylindrical sinkings 24CR, 24CG, and 24CB at their bottoms. The center axes 20CR and 20CB of the cylindrical sinkings 24CR and 24CB at both outer sides are made eccentric to the central electron gun axis side from the central axes 20R and 20B of the opening 24R1 and 24B1, formed at the bottoms, on the plane including the axes 20R and 20B, and their axis to axis distance S1 is a little smaller than the S0. On the other hand, the interval S2 between the openings 25R, 25G, and 25B of the G4 electrode 25 is made a little larger than the S0. In other words, the mutual relation of the axis to axis distances is, S1<S0<S2.
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