| 摘要 |
<p>PURPOSE:To cause uniform discharge at a lower voltage without charging mercury in a discharge gas by forming a discharge surface of a cathode out of a conductive oxide, containing at least one specified element, and an inorganic insulating material. CONSTITUTION:A conductive oxide, as a dischargeable substance, is selected to be an oxide containing at least one element from Ia, IIa, and IIIa group of the element periodic table, so that a lower work function and higher secondary electron emission efficiency can be obtained. Further, an inorganic insulating material, which has a high melting point without no degradation and gas release, is dispersed and provided as a non-discharging substance, in a particle shape, in the conductive oxide. Here, the covering rate of the inorganic insulating material is set to be from 20 to 70%. Whereby, since the conductive oxide has charge of a predetermined brightness and a predetermined voltage portion, and since the inorganic insulating material has charge of a predetermined area and uniform discharge portion, a cathode of a predetermined area can uniformly be discharged at the predetermined brightness and at the predetermined voltage, while charge of harmful mercury for a discharge gas can be eliminated.</p> |
