Full color, high contrast front projection on black emissive display

Abstract

Front digital projection (FDP) displays have the features of being portable, economical and scalable for large size displays. Unfortunately, existing FDP technologies suffer with poor image contrast in well-lighted environments, due to the "black-level" issues of the conventional white diffusive screens. More powerful projectors can be applied to enhance contrasts by increasing the brightness, at the expenses of significantly increased cost, weight, power consumption, and viewer eye fatigue due to the bright projection. In this joint paper, we demonstrate an innovative full color, high contrast front projective display system on a black emissive screen (BES). It comprises of a novel transparent fluorescent screen on pitch-black substrate, and a digital image projector with optic output that excite the fluorescent screen. The fluorescent layered screen is comprised of at least 3 layers of RGB emissive materials, which are made in fully transparent form. The "excitation" projector is based on DLP® projector platform, where a UHP lamp is filtered by a color filter wheel which sequentially excites the RGB emissive layers resulting in RGB emissions from the screen. This display combines the best of both worlds of front projection and emissive display technologies. Like projection displays, it is scalable and economic at large displays, the screen has no pixel structure and can be manufactured using a roll to roll method. Like emissive displays (e.g. plasma or field emission displays with phosphor screen), the quality of the emissive images on black back-plate is superior, with large viewing angles and superior contrasts in any environments. The new projection display can favorably compete with existing flat panel displays and other projection displays.