| 摘要 |
PURPOSE:To improve the landing properties of a color picture tube by a method in which the larger a substantial deflection angle obtained by multiplying a deflection angle of an electron beam, by cosine of the angle, between the diagonal axis and the long axis of the shadow mask becomes, the smaller the width of the minor side of the mask opening is formed. CONSTITUTION:A shadow mask having a rectangular phosphor screen and the longitudinally long openings is provided, while the electron beams are made to collide with the phosphor screen through the openings of the shadow mask. The shape of the shadow mask opening is so formed that, according to the distribution of the substantial deflection angles to be determined by the value obtained by multiplying a deflection angle of an electron beam by cosine of the angle, between the diagonal axis and the long axis of the shadow mask, the larger the substantial deflection angle becomes, the smaller the width of the minor side is formed. That is to say that the larger the equiangular line theta' of the substantial deflection angle becomes, the smaller the width of the minor side is formed. In this way, the landing properties of the colar picture tube can be improved. |
