Hitachi, Ltd.

Hiroki Taga

Kazumasa Hirai

Tatsuya Mochizuki

Yuichi Inoue

Katsuyuki Kawamura

A color picture tube has a panel which is substantially flat on its outer surface, while an inner surface of the panel is curved, and a shadow mask having a curved plane with a curvature that is greater than that of the curved plane on the inner panel surface. The panel is made of glass, such as a tint material, a ring-like magnet assembly (PCM) for convergence adjustment is provided outside of the neck, a first electromagnetic quadrupole coil is further attached to a portion outside of the neck for causing an electron beam spacing to change or vary in accordance with the deflection angle, and a second electromagnetic quadrupole coil is attached to a deflection yoke. The distance between adjacent ones of three cathodes of an electron gun is determined to be greater than or equal to 6.0 millimeters (mm).

Inline type color picture tube

In order to prevent doming effect in a shadow mask of a color cathode ray tube caused by thermal expansion of the shadow mask structure produced by heating of the shadow mask due to impingement of the electron beam thereon, the shadow mask is provided with a skirt portion along at least one side thereof. The skirt portion includes a long projection portion where the shadow mask is welded to the frame, an adjacent inclined portion which decreases in length in a direction away from the projection portion. Further, a short portion is disposed therebetween the inclined portion. The inclined portion decreases in length linearly or non-linearly.

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Mobara, Japan

Hiroki Taga