Abstract: A vertically aligned array of electron scanning beams independently modulated by individual sources of video signals are employed to significantly increase display definition in conventional cathode ray tube type monitors. Precise vertical alignment of scanning spots produced by the beam array is achieved by synchronizing the relative timing of the video signals associated with each of the beams using delay circuits. Vertical spacing between the scanning spots produced by the beam array may be selectively adjusted by electrostatic deflection plates. Vertical alignment and vertical spacing of the scanning spots are respectively sensed though the provision of narrow, vertical and diagonal slits in the fluorescent coating of the CRT screen. A photodetector positioned at the rear of the screen produces output signals in accordance with light delivered through the slits as the scanning spots traverse the slits.