| 摘要 |
<p>PURPOSE:To uniform the temperature of a substrate metal during its operation and restrain the variation of a color tone with temperature by forming a side edge-lead wires on the peripheral parts along the longitudinal direction on the back surface of a heat-resistant insulation substrate. CONSTITUTION:Snaking-like heating elements 5a-5c composed of three tungsten thin films are arranged in a straight line state on the back surface of a heat- resistant insulation substrate 1, and these heating elements 5a-5c are seriesly connected with a lead wire 5d. From the heating elements 5a and 5c in both sides, a ribbon-like side edge lead wire 7 extends to a 180 deg. opposite side along the peripheral part of the back surface of the heat-resistant insulation substrate 1 so as to be connected to a heater terminal 6. Since thus the side edge lead wire 7 is arranged on a peripheral part in a longitudinal direction on the back surface of the heat-resistant insulation substrate 1, heat loss produced via an outside lead wire can be relaxed, and also the emission from the peripheral part of the heat-resistant insulation substrate 1, of heat generated by a heating element 5 can be reduced. This enables the temperature of three substrate metals 2 to be uniformed, an electron emission characteristic to be stabilized, and thereby the variation of a color tone during an action to be restrained.</p> |
