61-2: Optical Efficiency Enhancement in Wide Color Gamut LCD by a Patterned Quantum Dot Film and Short Pass Reflector

Abstract

Liquid-crystal display (LCD) with patterned quantum dot (QD) film and short-pass reflector (SPR) was proposed and has an advantage for dramatically enhancement of optical efficiency compared to LCD prepared with a mixed QD film (reference). In proposed LCD structure, the optical power in blue, green, and red color was increased by 869%, 256%, and 85% compared with the reference, respectively. This enhancement comes from the two facts; 1) blue backlight is converted to green or red light separately by each patterned green or red QD film entered directly to each CF without any different color cut, 2) SPR reflects the backward emission of QD to forward direction, preventing the absorption loss of backward emission by back light unit. Additionally, we obtained high color gamut of NTSC 125% in our proposed LCD using a broad-band CF while maintaining the maximum optical intensity with relatively high CF transmittance. Author KeywordsLiquid-crystal display (LCD); quantum dot (QD); nanocrystal; patterned QD film; short-pass reflector (SPR); optical efficiency.

Review of nanostructure color filters

“…The color conversion efficiency can be improved by enhancing the quantum yield and color separation efficiency. In addition, the conversion efficiency can be further increased by increasing the number of QDs layers 140 and recycling the blue light. 141 Later that year, Kim et al proposed an LCD structure employing a short-pass filter (SPF) and a patterned QD film capable of realizing a very wide color palette shown in Fig.…”

Long-Term Stable Microlens Array-Integrated Quantum Dot/Siloxane Film for Thin White Backlight Units

“…Figure a–c indicates the PL intensity values of the neat, DF, and ML/QD films on blue LED chips formed by changing the thickness to optimize the white PL. The ratio of the red PL peak (∼640 nm) to the green PL peak (∼540 nm) increased because of the reabsorption of red QDs with the increase in thickness . For the neat and DF/QD films, a thickness of 240 μm was needed to realize the white PL (Figure a and b); this shows a tendency similar to that of the red QD film shown in Figure e.…”

“…The ratio of the red PL peak (∼640 nm) to the green PL peak (∼540 nm) increased because of the reabsorption of red QDs with the increase in thickness. 44 For the neat and DF/QD films, a thickness of 240 μm was needed to realize the white PL (Figure 4a and 4b); this shows a tendency similar to that of the red QD film shown in Figure 2e. However, the yellow ML/QD film showed white PL even when its thickness was 180 μm, which is 25% thinner than the neat QD film (Figure 4c).…”

Mini-LED, Micro-LED and OLED displays: present status and future perspectives

“…This filter also enhances the ACR so that no CP is required. In some designs, a distributed Bragg reflector (DBR) is inserted to selectively recycle the unconverted blue light 46 or to enhance the red/green output efficiency 47 . In Fig.…”