| abstract |
The invention relates to a controllable thermionic electron emitter for vacuum tubes, which comprises an emitter layer (3, 27) and a control layer (5) which is separated from the emitter layer by an insulating layer (4), with the insulating layer and the control layer being manufactured by a deposition process. Also when its dimensions are small, such an electron emitter can be dimensionally accurately manufactured. All functional elements of the controllable thermionic electron emitter, more particularly control layer(s) (5, 7, 22, 24), emitter layer (3, 27) and separating insulating layers (2, 4, 6, 21, 23, 25) are successively deposited on a substrate (1, 20) in the direction of growth, in such a manner that the layers adhere to each other via solid boundary layers. In operation and, in particular, when the temperature varies, the dimensional accuracy of the electron emitter is preserved within narrow limits, and said electron emitter has a long service life. |