| 摘要 |
PROBLEM TO BE SOLVED: To provide an extended shadow mask and its supporting frame which will not be affected by a local overheating, has an appropriate natural frequency of vibration and can efficiently with stand a sealing operation of a cathode-ray tube at a high temperature. SOLUTION: A masking device for a color cathode-ray display tube has formats of a flat screen, a supporting frame 3 for an extended shadow mask 2 and the extended shadow mask 2 that is attached to the supporting frame 3 so as to be bearable to extension in room temperature. In this device, the supporting frame 3 is made from a cured Fe-Ni alloy which has a thermal expansion coefficient of not more than 5×10-6K-1 within 20-150 deg.C and has a yield stress Rp0.2 of not less than 700 MPa at 20 deg.C, and the extended shadow mask 2 is made from a cured FeNi or an Fe-Ni alloy which have a thermal expansion coefficient of not more than 5×10-6K-1 within 20-150 deg.C. |
