Abstract: Color optical output apparatus comprising a color dependent mirror and a pair of optical spacial modulator arrays arranged to deflect light incident thereon, the arrangement being such that an incident polychromatic beam is split by said mirror means into two spectral components, one directed to each array, and said mirror means is arranged also to receive and combine deflected beams from each array to produce a combined optical beam, the spectral response of the mirror means being the same during splitting and combining.

Abstract: The gun comprises a cathode, a control grid, a first anode a second anode and a third anode. Preferably a beam width limiting aperture is provided in the first anode. In one example the current modulating voltage applied to the grid is 0 to -50V, the voltage applied to the first anode is +5 kV, the focus voltage applied to the second anode is +500V, and the EHT voltage applied to the third anode is +25 kV. A main focussing lens is formed by the second and third anodes, but the spacing of the first and third anodes is small so that the focussing effect is also substantially dependent on the voltage of the first anode. The field strength between the grid and first anode is high, which combined with the high first voltage produces a small crossover.