| 摘要 |
<p>PURPOSE:To enable the quick appearance of a picture image by shortening time from the start of electrification to that of electron emission by forming a heat-resistant black film on a heat-resistant insulation substrate. CONSTITUTION:A heat-resistant black film 7 is adherently formed on a part except a surface where the heating element 5 of a heat-resistant insulation substrate 1 is formed. When voltage is applied from a heater terminal 6, each of heating elements 5a-5c generates heat by Joule heat, and when a substrate metal 2 reaches a high temperature of about 800 deg.C, electron emission is stably made. At this time, the temperature of the black film 7 too becomes a high temperature of about 800 deg.C, the more temperature becomes higher, the more heat radiation loss from the insulation substrate 1 increases, and large input power is required to maintain an action temperature of about 800 deg.C. As a result of the increase of input power for heating the heating element 5, the temperature rise rate of the insulation substrate 1 after switch-on is quickened. This causes electron emission to be quickened to enable the quick appearance of a picture image.</p> |
