Narrow band 390 nm emitting phosphors for photoluminescent liquid crystal displays

Photoluminescent liquid crystal displays use a liquid crystal to modulate the intensity of ultraviolet light incident on visible emissive phosphors. In order to gain optimum performance from the liquid crystal in such a device, the activating light must cover a narrow spectral bandwidth very near to the visible (violet) region of the spectrum. Calcium sulphate europium phosphor offers an emission spectrum closely matching these requirements and has been incorporated inside low pressure mercury cold cathode fluorescent lamps. These have been used to backlight a photoluminescent liquid crystal display demonstrator.