Projection display system

A projection display system comprising an array of LEDs 10 in at least first and second rows 10a,10b, the LEDs in each row being spaced from each other. The LEDs in the second row 10b are offset in a direction parallel to the length of the row relative to the LEDs in the first row 10a. A micro-electro-mechanical system (MEMs) scanning mirror 11 is mounted for movement about an axis with a movement means for moving the MEMs mirror about the axis. The array of LEDs are positioned so that light emitted therefrom is directed towards the MEMs mirror and reflected therefrom to form a display 12 comprising one or more lines, each line comprising a plurality of pixels. The movement means is arranged so that light from said first row of LEDs and light from the second row of LEDs is used to form each line of the display so the spacing between pixels along each line of the display is reduced compared to the spacing of the LEDS in the rows of the array. The display system can be used in a head up display or helmet mounted display or in a digital printing system.