| 摘要 |
PURPOSE:To improve focus in the periphery of screen by increasing the thickness of the periphery of electron beam passing hole of second grid in the direction of vertical deflection and decreasing said thickness in the direction of horizontal deflection. CONSTITUTION:A concaved part 12 is provided along the periphery of electron beam passing hole 10 of the second grid of electron gun of in-line color picture tube. Thereby, thickness along the periphery of passing hole 10 is increased in the direction of vertical deflection and is decreased in the direction of horizontal deflection. In the cross-section of beam passing hole 10 analog its X-axis, thickness d1 along the periphery of hole is selected to 0.2D-0.4D with respect to the external diameter phiD of beam passing hole 10, beam diversion angle is suppressed to a certain degree, virtual crossover diameter is set small and thereby a beam diameter on the screen is set small. Meanwhile, when thickness d2 at the hole is set to 0.45-1D in the cross section along Y-axis, a beam diversion angle can be suppressed in the direction of vertical deflection and a halo in the vertical direction along the periphery of screen can be removed. |
