Method and plant for the production of a planar cathode for a flat picture tube

摘要

Such a cathode is formed by a plurality of heating wires which are located in a plane, covered with an emitting mass, and resiliently suspended from a frame. Since the electron emission in the flat picture tube of necessity has to be very uniform and so that in all heating wires a very uniform current has to flow, the heating wires have to be coated very uniformly with emitting mass. When the heating wires are coated as complete mesh grids or mesh grilles, it is not possible in every case to achieve the very uniform electrical field distribution required for a very uniform coating. According to the invention the heating wires are individually coated with the emitting mass and fastened one after the other to a frame of the flat picture tube. The heating wires are coated with the emitting mass in a cataphoresis bath and after the coating individually fastened to the frame by laser welding. <IMAGE>