| 摘要 |
PURPOSE: A heater for cathode ray tube is provided to prevent a crack of an alumina insulating layer and lengthen a lifetime of the heater by forming an insulating layer including acicular alumina particles. CONSTITUTION: An insulating layer is coated on a surface of a heater. Acicular alumina particles are included in the inside of the insulating layer. The content of the acicular alumina particles included in the inside of the insulating layer corresponds to 50 or more percent of the volume of total alumina particles. An aspect ratio of a short axis and a long axis of the acicular alumina particle is 5.0 or more, at least. A mean size of the acicular alumina particle is 5.0 to 10.0 micro meter on the basis of the long axis. The acicular alumina particles having sizes of 1.0 to 20.0 micro meter corresponds to 90 percent of the volume of the total acicular alumina particles on the basis of the long axis.
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