CATHODE OF ELECTRON TUBE

摘要

PROBLEM TO BE SOLVED: To restrain generation of distortion resulting from a thermal stress of a substrate supported with an inner wall of an end of a cylindrical support tube. SOLUTION: A notched part 21 is provided at an end of a support tube 2 on the side at which a substrate is supported. The part 21 has a depth smaller than the thickness of the substrate 1. Side surfaces of the substrate 1, an alloy layer 4 and an electron radiating material 5 layed thereon can be seen from the part 21. Accordingly, stress from the tube 2 given to the substrate 1 is alleviated. Consequently, accumulation of plastical deformation caused by plastical distortion of the substrate 1 can be reduced.