White LEDs using the sharp β-sialon: Eu phosphor and Mn-doped red phosphor for wide-color gamut display applications

The sharp β-sialon (Si6-zAlzOzN8-z : 0 < z < 0.1):Eu green phosphor, combining with a blue LED and CaAlSiN3:Eu red phosphor, is suitable for the wide-color gamut white LEDs backlighting system, because of its sharp and asymmetric emission spectrum shape. However, the color gamut and the brightness of the aforementioned display is restricted because of the wide emission band of the CaAlSiN3:Eu red phosphor. In this work, we used K2SiF6:Mn as an alternate red phosphor, which has a sharp emission spectrum. The display with the white LED using sharp β-sialon:Eu and K2SiF6:Mn shows a wide-color gamut, which covers the hole NTSC triangle. The use of K2SiF6:Mn enables to realize not only a wider color gamut but also a higher brightness of displays, compared with the use of CaAlSiN3:Eu. Furthermore, it is confirmed that the white LED using sharp β-sialon:Eu and K2SiF6:Mn is stable against temperature and also durable under the accelerated drive conditions.