| 摘要 |
In an image pick-up tube including a diode-type electron gun having a cathode electrode which emits a scanning electron beam and a control electrode which regulates the current of the electron beam at the cathode electrode and through which there is a control electrode current flow during operation of the tube, and a target electrode from which a video output current signal is obtained in correspondence to incident light from an object image projected on the target electrode as the latter is scanned by the electron beam; a beam control voltage signal is generated in response to the video output current signal, the beam control voltage signal is supplied to the control electrode of the electron gun for regulating the current of the electron beam at the cathode electrode, the control electrode current is detected during operation of the tube, and the generation of the beam control voltage signal is controlled in response to a signal corresponding to the detected control electrode current and which preferably determines the gain of an amplifier in the path of the beam control voltage signal. |
