Abstract: A CRT-matrix type big screen display system having self-emitting type picture cells is provided with a deflection waveform as a sawtooth waveform and a deflection waveform in the other direction as a step deflection waveform crossing the picture cells. Inclination of the scanning line is eliminated so that fluctuations in display brightness thereto are avoided and a satisfactory picture display is achieved. Also in CRT-matrix type big-screen display systems, index elements or cells are provided between sets of primary color cells and in the scanning direction. At least at the start of the scanning operation, the index elements or cells are scanned and the positional information thereof is stored in a memory for use in processing a video signal to achieve a satisfactory picture display.

Abstract: A large area display has a plurality of cathode ray tubes mounted adjacent each other in X, Y matrix and each cathode ray tube includes a plurality of pixels arranged in an X, Y matrix on a front panel and each pixel comprises three horizontally extending stripe-shaped luminous elements aligned in the vertical direction and the front panel of the cathode ray tube is formed with a thinner portion adjacent its outer edge where it joins to the funnel to reduce the spacing between adjacent cathode ray tubes to a minimum to allow the pixels to be viewed over a wider angle.

Abstract: An improved current dependent type color cathode ray tube which utilizes a color phosphor screen which has at least two phosphors that have current density versus brightness characteristics which differ from each other and which emit light of different colors and including an electron gun which emits an electron beam which impinges on the color phosphor screen and wherein the current density of the electron beam of the gun varies in response to color signals so as to cause the emission of the desired colors to produce a color image and wherein the focusing voltage of the electron gun is varied so that the just focussing state occurs at the highest drive current within the drive current range and the focal length associated with the focussing voltage at the just focussing state is displaced by more than 5% from the focal length represented by the lowest drive current.