A projection television system comprising an array of three projection television display tubes (14) luminescing in red, green and blue, a focusing lens (16) associated with each tube and a display screen (12) on which the respective optical images are merged to form a single multicolored image. At least one of the display tubes (14) has a multilayer interference filter (46) between the phosphor (30) and the faceplate (20). In order to imprve the light output at the corners of the display screen (12), the cut-off angle of the first filter layers is varied between the center and the corners thereof, for example by increasing the optical thickness of the filter layers relative to the center.