| 摘要 |
PURPOSE:To maintain a good emission life property of a cathode for a long life by applying high temperature heat treatment to powder of a heavy metal oxide in the process to form a coating consisting of a mixture of powder of a heavy metal oxide and a binder on the shadow mask surface. CONSTITUTION:In the process of forming a coating consisting of a mixture of powder of a heavy metal oxide and a binder by spraying or electrostatic coating process on the shadow mask surface, high temperature heat treatment is applied to powder of a heavy metal oxide. Powder of the heavy metal oxide is desirably to be a material having a large reflection factor to an electron beam, generally that consisting of a metal oxide containing an element having higher density or a larger atomic number than an iron plate being a constituent material of the shadow mask 3a and thereby a gas emission quantity from the coating due to heating and electron radiation in the manufacturing process of the coating is sharply reduced while lowering poisoning to a cathode thus making it possible to obtain a cathode-ray tube having a good cathode emission life property and a long life.
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