CPC Subgroup
H01J 19/30 characterised by the material
Full Title
Details of vacuum tubes of the types covered by group H01J21/00 > Non-electron-emitting electrodes; Screens > characterised by the material
H01J 19/30 Details of vacuum tubes of the types covered by group H01J21/00 > Non-electron-emitting electrodes; Screens > characterised by the material