Abstract: In a flat cathode ray tube display apparatus a low energy, electron beam (18) is directed substantially parallel to a faceplate (12) carrying a phosphor screen (14) in a space between a deflection electrode array (22) and the input side of an electron multiplier (16) adjacent the screen where it is deflected by operation of the electrode array (22) in field scann manner towards the screen to provide a raster scanning input to the multiplier. the deflector electrodes (23) of the array are switched successively between two voltage levels in each field to step the line scanning beam with the switching voltages in successive fields differing whereby two interleaved sets of display lines are drawn in two consecutive fields which together constitute a display frame having the required number of active display lines. The voltage switching circuit (52) may be carried on a substrate adjacent the electrode array.

Abstract: In a flat cathode ray tube display apparatus a line scanning, low energy, electron beam (18) is directed substantially parallel to a faceplate (12) carrying a phosphor screen (14) in a space between a deflection electrode array (22) and an input side of an electron multiplier (16) adjacent the screen where it is deflected by the electrode array (22) in field scan manner towards the screen. The deflector electrodes (23) in the array correspond in number to the conventional raster lines to be displayed and are switched successively between two voltage levels to step the line scanning beam. The electrodes' voltage switching drive circuit (52) may be carried on a substrate adjacent the electrodes thereby reducing the number of leadthroughs in the tube's envelope (15). For color display the screen comprises a pattern of different color phosphor elements and a color selection electrode arrangement (38) is situated at the output side of the multiplier (16).

Abstract: A color display system including a cathode ray display tube (10) of the kind which has an electron multiplier (16) arranged adjacent a luminescent screen (14) comprising a repeating pattern of three different color phosphor elements and pairs of color selection electrodes (38, 40) associated with each channel of the multiplier operable to control the direction of the electron beam from the channels for color selection purposes uses a switching bridge circuit comprising semiconductor switching device (52, 54, 56, 58), e.g. MOSFETs, connected between voltage supplies for switching the voltage applied to each one of the pair of electrodes between three respective levels in synchronism to achieve a predetermined color selection sequence. The semiconductor devices are controlled by synchronized waveforms from a pulse generating circuit (86) via optocouplers (88) enabling the switching bridge circuit to be floated at a high potential.

Abstract: Color display apparatus including a color display tube in which a single electron beam is scanned in television raster fashion across the input surface of an electron multiplier (16) adjacent a screen (14) comprising a repeating pattern of three different color phosphors, and in which deflection of the beam emanating from the multiplier onto respective ones of the three phosphors is controlled by color selection electrodes (38, 40) adjacent output apertures of the multiplier. The apparatus includes driving circuitry using line stores (64) which performs line scanning at three times the standard rate and controls switching of the color selection electrodes so as to display in turn the three color components of each standard picture line during the standard line period. Vertical scanning may be effected continuously or in stepped fashion.