Shadow mask having particular design of upper and lower holes for improved strength and halation characteristics

摘要

In a shadow mask color cathode ray tube, its shadow mask is not easily deformed into a concave shape when an impact or a vibration is applied to the shadow mask, so that a good image can be displayed. The electron beam passing holes of the shadow mask are each formed of an upper hole etched from the panel side of the shadow mask and a lower hole etched from the electron-gun side of the shadow mask. In each electron beam passing hole located in the peripheral portion of the shadow mask, the ratio of an upper-side etching quantity to a lower-side etching quantity is controlled to be 1.8 or less. By adjusting the balance in strength relative to compressive stresses between the panel side and the electron-gun side of the shadow mask, it is possible to prevent the shadow mask from being deformed into a concave shape.