The optical properties and quantum efficiency of potential red K5Eux(WO4)(2.5+1.5x) (x = 0.5-3.0) phosphors for a novel phosphor liquid crystal display (LCD) are measured under near-UV excitation (394 nm). The quantum efficiency of K5Eu2.0(WO4)(5.5) phosphor fired at 900 degreesC for 3 h is 0.46 at 365 nm and 0.54 at 394 nm. The optical and morphological suitability of K5Eux(WO4)(2.5+1.5x) phosphors is discussed for their application in phosphor LCDs. The emission peak of K5Eu2.0(WO4)(5.5) phosphor is located at 615 nm and the Commission International del'Eclairage (CTE) coordinates are x = 0.63, y = 0.33.