Abstract: A television camera tube with electrostatic focusing comprising a triode section at the first stage having a cathode a first grid and a second grid, an electrostatic focusing lens section at the next stage having a third, fourth and fifth grids of cylindrical electrode configuration, and a sixth grid with mesh electrode configuration at the last stage, these electrodes being coaxially arranged in a cylindrical glass envelope, the length of the fourth grid is greater than 1.15 times the inner diameter thereof but equal to or smaller than 2.30 times the inner diameter thereof.

Abstract: A vidicon type camera tube comprising a beam current control section including a thermionic cathode, a first grid having an aperture of diameter d.sub.1, a second grid having an aperture of diameter d.sub.2 and a beam disc having a diaphragm of diameter d.sub.3 disposed at a distance of l along the tube axis from the second grid. The tube further comprises a main lens section constituted of cylindrical electrodes. The diameters d.sub.1, d.sub.2 and d.sub.3 and the distance l are so determined that the value of (d.sub.2 /l)(d.sub.3 /d.sub.1).sup.2 may lie in the range where the difference of the effective cathode loading is positive.

Abstract: A television camera tube with electrostatic focusing and magnetic deflection comprises in an cylindrical envelope a beam current control, a main lens section and a sixth grid in the form of a mesh electrode. The beam current control section includes a cathode, a first grid and a second grid with an electron beam limiting diaphragm in this order. The main lens section includes third, fourth and fifth grids in the form of cylindrical electrodes disposed in this order. Around the cylindrical envelope is mounted a magnetic deflection coil whose length along the envelope axis is 0.18 to 0.40 times the distance from the beam limiting diaphragm to the mesh electrode.

Abstract: A driver system of a display panel including a matrix of luminescent elements with a bi-stable operation condition comprises a circuit arrangement for combining a plurality of divided lighting periods to provide a gray-scale display and a circuit arrangement for increasing or decreasing the respective widths of the divided lighting periods in correlation with each other, whereby a control of luminance with gray-scale is provided.

Abstract: A flat display panel uses a DC gas-discharge and has flat discharge display elements, which elements have three electrodes composed of a cathode, a grid and an anode and a discharge stabilizing resistor. An auxiliary discharge is formed by using the discharge stabilizing resistor, the cathode and the grid in an auxiliary discharge space defined between the grid and the cathode. A main gas discharge is formed in a main discharge space defined between the anode and the grid by mainly using electrons in a plasma, produced in the auxiliary discharge space, which are diffused and accelerated into the main discharge space. The flat discharge panel, in order to provide a memory function in the main discharge is driven by the use of pulse voltage applied between the anode and the grid.

Abstract: A system for driving a display device having photo elements driven by pulsed current from pulsed current sources in which the firing voltage or operating voltage of the photo elements differs from the extinction voltage thereof. The system includes apparatus for setting the voltage applied to the photo elements to a value less than the extinction voltage at a time near the trailing edge of the pulsed current.