▎ 摘　　要

NOVELTY - The cathode has a B-type barium-tungsten cathode layer(2) whose upper surface is coated with a graphene layer (1). The B-type barium-tungsten cathode layer is formed in a supporting cylinder (3). The B-type barium-tungsten cathode layer in the supporting cylinder is provided with a filament, where the graphene layer is a single-layer or double-layer graphene. A gate and the graphene layer are separated with each other by insulating medium layer or vacuum, where the gate is a ring-shaped or net-shaped structure. An anode emits cathode excitation light from an incident cathode by a mesh structure. USE - Graphene coated barium-tungsten cathode. ADVANTAGE - The cathode improves light emitting ability, reduces working temperature, and prolongs cathode service life. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a graphene coated barium-tungsten cathode manufacturing method. DESCRIPTION OF DRAWING(S) - The drawing shows a side sectional view of a graphene coated barium-tungsten cathode. Graphene layer (1) B-type barium-tungsten cathode layer (2) Supporting cylinder (3)