Application of photoluminescence phosphors to a phosphor-liquid crystal display

Abstract

The photoluminescence properties and quantum efficiency of potential red, green, and blue (RGB) phosphors are measured under near-ultraviolet excitation (380–420 nm). The suitability of several phosphors is discussed for their application in phosphor-liquid crystal displays (LCDs). K5Eu2.5(WO4)6.25, SrGa2S4:Eu, and BaMgAl10O17:Eu phosphors are chosen as RGB phosphors for making a phosphor-LCD prototype. The color coordinates and optical properties of phosphor-LCDs are compared to those of conventional LCDs.

Measuring the absolute quantum efficiency of luminescent materials

“…The literature values are often reported under 254 and 365 nm excitation. The QE of BAM:Eu has been reported to be 91% [9] and 88% [5] under 254 nm excitation, 93% under 365 nm excitation [6], and 72% under 394 nm excitation [6]. The QE of ZnS:Cu,Al under 365 nm excitation is reported to be 89% and 80% under 394 nm excitation [6].…”

“…The QE of BAM:Eu has been reported to be 91% [9] and 88% [5] under 254 nm excitation, 93% under 365 nm excitation [6], and 72% under 394 nm excitation [6]. The QE of ZnS:Cu,Al under 365 nm excitation is reported to be 89% and 80% under 394 nm excitation [6]. Nanoparticles of ZnO:Zn are reported to have QE values of 20% and 12% under 280 nm excitation [16], the QE increasing with decreasing particle size.…”

“…Defining the measurable quantity O ¼ ðbI gas Þ À1 À ðbI 0 gas Þ À1 ðbI 0 gas Þ À1 ðP s ex Þ À1 À ðP 0 ex Þ À1 ðP 0 ex Þ À1 , (A. 6) we see that O ¼ A cal =A sys ; or A sys ¼ A cal =O: Here P 0 ex ¼ bI 0 gas is the power measured by the detector at the excitation port without the sample inserted, and P s ex is the power with the sample inserted. As a matter of interest, b can be determined by noting…”

“…Quantum efficiency has long been used as a criterion for the selection of luminescent materials for application in fluorescent lighting [2][3][4], flat panel displays [5,6], and more recently, solid-state lighting. A problem with some QE measurement techniques described in the literature is the lack of an acceptable calibration standard.…”

A universal HF‐free synthetic method to highly efficient narrow‐band red‐emitting A2XF6:Mn4+ (A = K, Na, Rb, Cs; X = Si, Ge, Ti) phosphors

“…White light‐emitting diodes (wLEDs), as burgeoning backlight units, have been widely applied in modern liquid crystal displays (LCDs), due to their excellent features such as high brightness, wide color gamut, low power consumption, and high reliability . Currently, wLED backlights are mainly fabricated by pumping individual green and red phosphors by an InGaN blue LED, thus the primary RGB colors can be achieved using appropriate color filters . In this technology, therefore, highly efficient and reliable phosphors with narrow‐band emissions are the key to obtain high‐performance wLED backlights with high brightness, long lifetime, and wide color gamut .…”