| 摘要 |
In an increased-diameter funnel section and a almost pyramidal decreased-diameter yoke section constituting the funnel section of the envelope of a cathode-ray tube, the outside surface of the yoke section between a neck connecting portion on which a neck and the yoke section are coupled and a position close to a boundary of a increased funnel section, on which deflection yoke is provided, is shaped so as to fulfill the following expression:where the index value indicating the degree of rectangle at the deflection reference position is alpha0 and the minimum of the index values in the whole area of the yoke section is alphamin. This makes it possible to provide a cathode-ray tube apparatus which secures a sufficient strength of the vacuum envelope to atmospheric pressure even when the yoke section is made pyramidal and which reduces the deflection power effectively and thereby fulfills the demands for higher luminance and higher-frequency deflection.
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