Toppan Printing developed an organic EL colour screen (RGB). This 5" QVGA prototype has a pixel pitch of 360 microns and a 70ppi resolution. Important information to remember is that the technique for the RGB colours is very similar to that used in printers, as (to put it very simply) ink is used to colour the screen. The challenge for this company will be the production of bigger - let’s say 20" - screens with a 200ppi resolution.