DIFF Subgroup
H01J 19/30 characterised by the material
Introduced: September 1968
Full Title
Full titles differ between systems:
IPC:
Details of vacuum tubes of the types covered by group > Non-electron-emitting electrodes; Screens > characterised by the material
CPC:
Details of vacuum tubes of the types covered by group H01J21/00 > Non-electron-emitting electrodes; Screens > characterised by the material
No child classifications to compare. This is a leaf node in both IPC and CPC.