| 摘要 |
PROBLEM TO BE SOLVED: To provide a glass funnel capable of being shortened in depth and reduced in weight without increasing stress by forming a body section out of arch face sections, erected nearly vertically to an opening end section and provided with arch-shaped ridge line sections having both ends near the corner sections of the opening end section and a dome-shaped section. SOLUTION: A body section 3 is provided with ridge line sections 8 on the sides of an opening end section and arch face sections 12 nearly perpendicular to an opening end face 11. The end sections of the ridge line sections 8 are located at the corner sections of the opening end section, and the arch face section 12 is inclined against the opening end face 11 by about 5-15 deg., thereby the rigidity of the body section 3 as a vacuum envelope is improved, the stresses can be reduced, and this cathode-ray tube can be made lightweight. The angle θ between tangential lines at the contact point between a blended R section on the ridge line section at the center of each side and the arch face section 12 and at the contact point between the blended R section and a dome-shaped section is preferably set to 90 deg.<=θ<=120 deg., and the curvature of radius R mm of the blended R section is set to R<=0.07 D-9.6 with respect to the maximum diameter D mm of the opening end section.
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