Implosion-protected cathode-ray tube

摘要

An implosion-protected cathode-ray tube has a bulb and a metallic band tightly binding the front outer peripheral portion of the bulb to suppress the occurrence of accidental implosion of the bulb during the manufacturing processes including a heating and evacuation process and a rapid cooling process after the heating and evacuation process as well as after the manufacture of the cathode-ray tube. The material forming the metallic band and the size of the metallic band meet the following conditions: i) the thermal expansion coefficient alpha s of the material is not less than the thermal expansion coefficient alpha g of the glass forming the bulb; ii) a value expressed by: L(1+ alpha s. delta t), where L is the inner perimeter of the metallic band at the ambient temperature when the tightened metal band is removed from the bulb and where alpha t is the temperature differential between the ambient temperature and a temperature for a heating and evacuation process, is smaller than the perimeter of the front outer peripheral portion of the bulb on which the metallic band is shrunk, during the heating and evacuation process, and iii) a stress corresponding to the yield point of the material of the metallic band remains in the metallic band at the ambient temperature.