Oblon, Spivak, McCelland, Maier & Neustadt
Thermionic cathode structure
 A thermionic cathode structure comprises two parallel thermionic electron emitter elements which are made of a heat resistant and electric conductive inorganic compound. Each of them has one end electrically closed and the other end functioning as a current feeding port. 
Denki Kagaku Kogyo Kabushiki Kaisha
H H H
H01J H01J H01S
inventional inventional inventional
Suzuya Kenichi Hirotoshi Mitsuaki Yoshiharu
Yamada Ehara Hagiwara Saito Mori