Abstract: An apparatus for controlling the deflection of an electron beam in an image pick-up tube of the type including a target screen, an electron gun for generating the electron beam, and a deflection device for causing the generated electron to scan the target screen includes a circuit for generating a saw-tooth signal having a first portion for causing the beam to scan a raster or effective image area on the target screen at a first scan velocity and a second portion for causing the beam to scan an over-scan area on the target screen outside of the raster image area at a second scan velocity faster than the first scan velocity, a circuit for changing the average level of the second portion of the saw-tooth signal relative to that of the first portion of said saw-tooth signal, and a circuit for supplying the output of the level changing circuit to the deflection device so that the electron beam is defocused on the over-scan area of the target screen for fully scanning such over-scan area.

Abstract: In an image pickup apparatus or television camera tube in which a signal corresponding to a target current of the television camera tube is supplied to its beam current control electrode to thereby control the beam quantity to become corresponding to the variation of the incident light amount thereon, the present invention is to provide an automatic beam current control system for a television camera in which the signal corresponding to the target current is supplied through a line adder circuit to the beam current control electrode.The line adder circuit may use, for example, a one horizontal period delay line. Since the control signal supplied to the beam current control electrode is an added value or an average value of the target currents obtained over two scanning periods, the stable control signal is always supplied to the beam current control electrode of the television camera tube so that the image picked up signal of high definition without a line crawl component can be obtained.

Abstract: In a circuit for controlling beam current in an image pick-up tube, suitable bias potentials are applied to the photo-conversion layer and the control grid electrode of the image pick-up tube, and a periodical beam blanking bias is applied to the cathode electrode by means of first and second switching devices, such as transistors, connected in series between different reference potentials with a junction point between the switching devices being connected to the cathode electrode of the pick-up tube, and with a blanking pulse signal controlling the first and second switching devices so tha the latter act in a complemental manner.