Nd3+:YAG transparent ceramics sintered under atmospheric pressure for improving the color gamut of LED-lit LCD

Abstract

In order to improve the color gamut of white light emitting diodes (wLEDs) for LCD backlights, Nd 3+ -doped YAG transparent ceramics were used as the color filters to provide pure green and red colors to improve the color gamut. The Nd 3+ :YAG transparent ceramic color filters were prepared by the solid-state reaction method. Compared with the glass filter and the phosphor-in-glass filter, Nd 3+ :YAG transparent ceramics have better heat dissipation capacity. Moreover, Nd 3+ :YAG and Ce 3+ :YAG transparent ceramics are of the same host materials, therefore the refractive index of them is almost the same, and the light loss at the interface is expected to be negligible. The wLED prototypes fabricated by stacking a blue LED chip with the Ce 3+ :YAG ceramic phosphor plate and the Nd 3+ :YAG transparent ceramic filter, due to the sharp and strong absorption of Nd 3+ : 4 I 9/2 → 4 G 5/2 , 2 G 7/2 transition, the color gamut of the light source prototype has been increased from 77.36% to 86.79%, which indicated that it may have a promising prospect in improving the color gamut of wLEDs for LCD backlight displays. • Nd 3+ :YAG ceramics were prepared by sintering in oxygen under atmospheric pressure. • The Nd 3+ :YAG transparent ceramic showed high thermal conductivity. • Nd 3+ :YAG ceramic used for filtering can increase the color gamut by 9.43% NTSC standard.