Narrow-band high-transmittance birefringent filter and its application in wide color gamut display

We propose a narrow-band birefringent filter and its application in wide color gamut.The birefringent filter consists of five phase retarders and two polarizers,and it has both narrow band and high transmittance.In the experiment,we fabricate the birefringent filter using quartz phase retarders and polarizers,and apply it in serval different displays.The color gamuts of displays are enhanced more than 30%NTSC(National Television System Committee),and the widest color gamuts that have been obtained are 126%NTSC in liquid crystal displays and 138%NTSC in organic light-emitting devices.Moreover,the deep blue light in spectrum of display can be reduced using the birefringent filter.The birefringent filter can be an efficient element to achieve wide color gamut display.

Wide color gamut switchable autostereoscopic 3D display based on directional quantum-dot backlight

A switchable autostereoscopic 3-dimensional(3D) display device with wide color gamut is introduced in this paper. In conjunction with a novel directional quantum-dot(QD) backlight, the precise scanning control strategy, and the eye-tracking system, this spatial-sequential solution enables our autostereoscopic display to combine all the advantages of full resolution,wide color gamut, low crosstalk, and switchable 2D/3D. And also, we fabricated an autostereoscopic display prototype and demonstrated its performances effectively. The results indicate that our system can both break the limitation of viewing position and provide high-quality 3D images. We present two working modes in this system. In the spatial-sequential mode,the crosstalk is about 6%. In the time-multiplexed mode, the viewer should wear auxiliary and the crosstalk is about 1%,just next to that of a commercial 3D display(BENQ XL2707-B and View Sonic VX2268 WM). Additionally, our system is also completely compatible with active shutter glasses and its 3D resolution is same as its 2D resolution. Because of the excellent properties of the QD material, the color gamut can be widely extended to 77.98% according to the ITU-R recommendation BT.2020(Rec.2020).

Determination of Color Gamut of Higher Plant Leaves Using the Law of Additive Color Mixing

Chlorophylls and carotenoids are the main pigments in leaves of higher plants. They combine to give color to leaves. Based on the CIE1931 chromaticity coordinates of chlorophylls and cartotenoids, which were obtained from their classical absorption spectra and the law of additive color mixing, the theoretical color gamut of higher plant leaves is determined. The theoretical prediction agrees well with our experimental results.

大型体育赛事中的超高清电视信号应用进展

超高清电视(UHDTV)是广播电视目前的发展热点和方向。从2016年开始,国际上一些主要的体育赛事提供方逐步开始进行超高清的转播实践。本文以2016年欧洲杯、2018年冬奥会以及2018年世界杯为例,分析了国际上主要体育赛事超高清转播的发展。

Macadam’s theory in RGB laser display

We have developed Macadam’s theory to deal with RGB laser display, which can well describe the color gamut display system varying with the laser bandwidth. By calculating the volume of R¨osch–Macadam color solid of laser display system under the Rec.2020 standard, we can obtain that the volume of chromatic stereoscopic at 30-nm laser spectral linewidth is about 90% of that at 1 nm laser spectral linewidth, which is important in laser display system to trade off the color gamut and the suppression of laser speckles. Moreover, we can also calculate the color gamut volume with different primary numbers and different primary wavelengths.

Investigation of Quantum Dot Color Filter Micro-LED Display

In this work,we present the investigation of the quantum dot color filter(QDCF)micro-light emitting diode(micro-LED)display.Green and red quantum dot photoresist(QDPR)materials are patterned into a pixelated array and precisely bonded with an all-blue micro-light emitting diode(micro-LED)substrate,forming a red,green,and blue(RGB)full color display through color conversion.A few factors that influence the achievable color gamut are further investigated.The resulting 1.1-inch 228-pixels per inch(ppi)display demo shows the good performance.The findings in this paper pave a way to the future industrialization of the micro-LED display.

Highly efficient and stable white LEDs based on pure red narrow bandwidth emission triangular carbon quantum dots for wide-color gamut backlight displays

High-performance white light-emitting diodes (WLEDs) hold great potential for the next-generation backlight display applications.However,achieving highly efficient and stable WLEDs with wide-color-gamut has remained a formidable goal.Reported here is the first example of pure red narrow bandwidth emission triangular CQDs (PR-NBE-T-CQDs) with photoluminescence peaking at 610 nm.The PR-NBE-T-CQDs synthesized from resorcinol show high quantum yield (QY) of 72% with small full width at half maximum of 33 nm.By simply controlling the reaction time,pure green (PG-) NBE-T-CQDs with high QY of 75% were also obtained.Highly efficient and stable WLEDs with wide-color-gamut based on PR- and PG-NBE-T-CQDs was achieved.This WLED showed a remarkable wide-color gamut of 110% NTSC and high power efficiency of 86.5 lumens per Watt.Furthermore,such WLEDs demonstrate outstanding stability.This work will set the stage for developing highly efficient,low cost and environment-friendly WLEDs based on CQDs for the next-generation wide-color gamut backlight displays.

Green and red phosphor for LED backlight in wide color gamut LCD

Wide color gamut(WCG) backlight for liquid crystal display(LCD) utilizing white light-emitting diodes(LED) has attracted considerable attention for their high efficiency and color reduction.In this review,recent developments in crystal structure,luminescence and applications of phosphors for wide color gamut LED backlight are introduced.As novel red phosphors,Mn4+activate fluoride and aluminate phosphors are advanced in quantum efficiency,thermal quenching and color saturation for their characteristic spectrum with broad excitation band and linear emission.The crystal structure and fluorescence properties of Mn4+doped fluosilicate,fluorogermanate,fluotitanate,as well as Sr4 Al14O25,CaAl12O19 and BaMgAl10O17 phosphors are discussed in detail.A serial of narrow-band red-emitting Eu2+,Eu3+and Pr3+-doped nitride silicates and molybdate phosphors are also introduced.Rare-earth-doped oxynitride and silicate green-emitting phosphors have attracted more and more attention because of the wide excitation,narrow emission,high quenching temperature,high quantum efficiency,such as β-sialon:Eu2+,Ba3Si6O12N2:Eu2+,MSi2O2N2:Eu2+(M=Ca,Sr,Ba),y-AlON:Mn2+and Ca3Sc2Si3O12:Ce3+.All above phosphors demonstrate their adaptability in wide color gamut LCD display.Especially for Mn4+doped fluosilicate red phosphor and β-sialon:Eu2+green phosphor.To achieve an ultra-high color gamut in white LED backlight and against the OLED,innovative narrow-band-emission red and green phosphor materials with independent intellectual property rights are continuously pursed.

Determination of luminous color gamut of continuous emissions in visible waveband

Regarding objects of monotonic emissivities in the visible waveband, the concept of color-kernel body is put forward. With this concept, the luminous color of actual objects is found out to be the mixture of the radiative colors of a blackbody and a color-kernel body with different weights. The locus of the isothermal radiative colors is a straight-line segment in the chromaticity diagram. The whole color gamut of continuous emissions is about 17% of the entire gamut of natural colors and at its bottom.

Going beyond the limit of an LCD’s color gamut

In this study,we analyze how a backlight’s peak wavelength,full-width at half-maximum(FWHM),and color filters affect the color gamut of a liquid crystal display(LCD)device and establish a theoretical limit,even if the FWHM approaches 1 nm.To overcome this limit,we propose a new backlight system incorporating a functional reflective polarizer and a patterned half-wave plate to decouple the polarization states of the blue light and the green/red lights.As a result,the crosstalk between three primary colors is greatly suppressed,and the color gamut is significantly widened.In the experiment,we prepare a white-light source using a blue light-emitting diode(LED)to pump green perovskite polymer film and red quantum dots and demonstrate an exceedingly large color gamut(95.8%Rec.2020 in Commission internationale de l'éclairage(CIE)1931 color space and 97.3%Rec.2020 in CIE 1976 color space)with commercial high-efficiency color filters.These results are beyond the color gamut limit achievable by a conventional LCD.Our design works equally well for other light sources,such as a 2-phosphorconverted white LED.

The Effect of Quantization Error on Display Color Gamut Transformation

Researchers and designers who work with color displays often transform color gamut between two different display devices. This paper demonstrates the effect of quantization error on the transformation based on analyzing the color gamut deviation profoundly.

用于安全编码的双模式上转换纳米光开关（英文）

镧系离子掺杂的NaYF_4油墨由于其独特的上转换光致发光特性可以被应用到防伪领域.本文首先通过高温共沉淀法合成了三种核-壳结构的镧系离子掺杂的NaYF_4上转换纳米材料,它们在808和980 nm激光激发下均可以表现出差异性的上转换荧光性能.其次,通过物理混合808 nm激发的不同颜色的悬溶液红绿蓝,可以调节混合液的发光颜色,实现全彩色显示. 808 nm激发产生的颜色可以实现比sRGB和印刷CMY颜色空间模型更宽的色域.最后,我们使用传统丝网印刷技术印刷出中国十二生肖图案和其他大面积的复杂图像,印刷图案在808 nm激发下可以呈现出一组多色连续的图案,同时在980 nm激发下也可呈现出另一组逐渐改变的多色图案,而且,印刷在透明聚氯乙烯PVC标签的图案可以附在酒瓶包装上,实现酒瓶包装的防伪.基于NaYF_4的双模式荧光图案可以替代传统单模式荧光图案,实现高水平的全色防伪及安全编码.

Flat-Panel Laser Displays Based on Liquid Crystal Microlaser Arrays

Laser displays,benefiting from the characteristic merits of lasers,have led to the revolution of next-generation display technologies owing to their superior color expression.However,the acquisition of pixelated laser arrays as self-emissive panels for flat-panel laser displays remains challenging.Liquid crystal(LC)materials with excellent processability and optoelectronic properties offer considerable potential for the construction of highly ordered multicolor laser arrays.Here,we demonstrate flat-panel laser displays on LC microlaser pixel arrays through a microtemplate-assisted inkjet printing method.Individual organic red-green-blue(RGB)microlaser pixel arrays were obtained by doping dyes into LCs with photonic band edges to obtain single-mode RGB lasing,leading to a much broader color gamut,compared with the standard RGB color space.Then we acquired periodically patterned RGB pixel matrices by positioning LC microlasers precisely into highly ordered arrays,according to the well-organized geometry of the microtemplates.Subsequently,we demonstrated full-color flat-panel laser displays using the LC microlaser pixel matrices as self-emissive panels.These results provide valuable enlightenment for the construction of next-generation flat-panel laser display devices.