with compounds having metallic conductive properties, e.g. lanthanum boride, as an emissive material

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Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps (details of electron-optical or ion-optical arrangements H01J3/00) > Main electrodes > Solid thermionic cathodes > characterised by the material > with compounds having metallic conductive properties, e.g. lanthanum boride, as an emissive material