METHOD AND APPARATUS FOR REMOVING FOREIGN MATTERS FROM A CATHODE-RAY TUBE

摘要

In a color cathode-ray tube, only a foreign matter adhering to a shadow mask is removed effectively without thermal deformation of the shadow mask or thermal denaturation of phosphors. An electron beam produced by an electron gun incorporated in a cathode-ray tube itself is scanned or irradiated to all over a shadow mask of the color cathode-ray tube. The radiant state of a fluorescent screen at this stage is checked to detect a foreign matter adhering to the shadow mask. The electron beam is deflected to align with the position at which the foreign matter is detected, and then irradiated to the foreign matter in the form of pulses. Thus, the foreign matter is heated and removed.