| 摘要 |
PURPOSE:To realize a highly sensitive deflection expanding lens and to reduce the full length of a CRT, by setting the mutual inter vals to make the difference between the interval of the first pair of planes and that of the fourth pair of planes within + or -20 %. CONSTITUTION:A deflection expanding lens consists of the first and the second cylindrical electrodes 18 and 19. The first cylindrical electrode 18 consists of the first pair of planes 21 and 22, and the second pair of planes 23 and 24, while the second cylindrical electrode 19 consists of the third pair of planes 27 and 28, and the fourth pair of planes 29 and 30. In this case, the difference between the mutual interval of the first pair of planes 21 and 22, and that of the fourth pair of planes 29 and 30, at the portion of tongues 25 and 26, is set to be within + or -20 %. In such a composition, a hyperbora distribution approximate to an ideal quadrupole lens is obtained, making the effective area to the lens aperture larger. Moreover, both the concave lens in the x direction and the convex lens in the y direction are made stronger, and the deflection sensitivity is made larger. Therefore, a CRT with shorter full length can be realized.
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