| 摘要 |
PURPOSE:To secure such a regenerated image that is excellent in high resolution as well as to make mass production easier, by setting a diagonal diameter of an electron beam scanning area to a range of 55-75% of an opening diameter of an electrode forming a collimation lens. CONSTITUTION:A diagonal diameter of an effective scanning area 16 for electron beams 15 is set to a range of 55-75% of an opening diameter of an electrode forming a collimation lens. In relation with the ratio of the diagonal diameter of the effective scanning area 16 to an electron lens (collimation lens) diameter in case of color signal frequency being fixed, if an effective scanning area ratio is more than about 55%, the specified capacity is securable. And, in a relationship between deflection aberration and picture deformation at the effective scanning area ratio and an image peripheral part, if the effective scanning area ratio is less than 75%, the specified capacity is securable as well. Thus, when the effective scanning ratio is set to be within the range of 75% from the said 55%, such a camera tube as having sufficient capacity and function can be mass-produced while satisfying a demand for miniaturization.
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