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摘要: 量子点材料因具有发光波长可调,色度纯,量子效率高等优异特性而受到广泛关注,在光致发光高色彩显示方面有着巨大的应用潜力。本文综述了量子点背光技术的研究进展,主要对比了QDs On-Chip、QDs On-Surface及QDs On-Edge 3种量子点背光主流技术的基本原理及结构,并分析了它们在液晶显示领域的应用,未来前景及面临的挑战;然后介绍了几种新型的量子点背光技术,并对两种量子点背光新技术进行重点说明:一种是采用低温注塑成型工艺将量子点与高分子材料均匀混合为一体,用于制备直下式背光的量子点体散射型结构扩散板;另一种新技术是采用丝网印刷或喷墨打印工艺将量子点转印至导光板表面,形成应用于侧入式背光的量子点网点微结构导光板。这两种背光都具有制备工艺简单、成本低、生产效率高等特点,对高色域液晶显示的研究及发展意义深远。Abstract: Quantum dots (QDs) have received widespread attention because of their adjustable emitted wavelength of light, color purity and high quantum efficiency, which have great potential in applications requiring high-color-quality displays with photoluminescence. In this paper, the progress of QD backlights based on each QDs on-chip, QDs on-surface and QDs on-edge are reviewed, including their principle, structures and current applications. Then, several other novel QD backlight structures are also introduced, prompting a proposal for two novel QD backlight technologies. One is the QDs scattering diffusion plate, which is prepared by injecting molding with a mixture of QDs and polymer at a low temperature. The other is a QD microstructure light guide plate, which is fabricated by transferring QDs on the surface of a light guide plate through screen printing or inkjet printing. Both of these two QD plates can achieve high color gamut while being simple to process, being low in cost and holding high production efficiency. These have wide applications in high color gamut liquid crystal displays.
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图 13 (a) 5.5英寸红、绿单色量子点导光板背光模型[58];(b)5.5英寸白平衡量子点背光模组和字符图案背光模型[58];(c)量子点膜片与量子点网点导光板示意图[58];(d)量子点散射网点的荧光显微镜局部放大图[58];(e)单个量子点散射网点的三维图像及其相应轮廓[58]
Figure 13. (a) Backlight module of 5.5-inch red/green monochromatic QDs[58]; (b) backlight module of 5.5-inch white-balance QDs and the specific partition backlight for the characters "FZU"[58]; (c)shematic diagrams of QD sheet and QD LGP[58]; (d) partial magnification of fluorescence microscope of the quantum dots microstructure array[58]; (e) 3D image and the corresponding profile of a single QD microstructure[58]
表 1 量子点槽结构与量子点膜片结构背光对比表[38]
Table 1. Backlight contrast table of QDs slot structure and QDEF structure[38]
Structure CIE(X, Y) CCT/K Lum/nit QDs Usage/num Film-a (0.354 09, 0.296 48) 4 226.8K 3 235.3 4.78×1019 Slot-b (0.359 32, 0.304 66) 4 070.7K 6 765.7 3.58×1017 表 2 LCD各背光技术对比
Table 2. Contrast of different LCD backlight technologies
YAG荧光粉
技术On-chip
结构On-edge
结构On-surface
结构量子点槽
结构量子点棒
技术量子点扩
散板技术量子点网点
微结构技术典型
结构光学硅胶
+荧光粉光学硅胶
+量子点细玻璃管
+量子点阻隔膜+量子
点层+阻隔膜光学封装胶
+量子点量子点棒 聚合物+
量子点导光油墨
+量子点色域
(NTSC)72% 82%~90% 100% 110% - - >120% >120% 工作
温度高温
(150℃)高温
(150℃)较高温度 较低温度
(室温)较高温度 较低温度
(室温)较高温度 较低温度
(室温)寿命 较高 低 较高 较高 - 较高 - - 量子点
用量无 少
(10kg/年)较少
(1t/年)多
(100t/年)少 - 少 少 结构 不改背光
结构不改背光
结构需增加
组件需增加
组件不改背光
结构不改背光
结构不改背光
结构不改背光
结构结构
利用率低 高 中 低 高 高 中 高 成本 低 芯片成本高 较低 较高 较低 较高 较高 较低 工艺 简单 复杂 简单 简单 简单 复杂 简单 简单 -
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