scholarly journals Tripling the Optical Efficiency of Color-Converted Micro-LED Displays with Funnel-Tube Array

Crystals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 39 ◽  
Author(s):  
Fangwang Gou ◽  
En-Lin Hsiang ◽  
Guanjun Tan ◽  
Yi-Fen Lan ◽  
Cheng-Yeh Tsai ◽  
...  
Keyword(s):  
Light Intensity ◽  
Epitaxial Growth ◽  
Optical Density ◽  
Contrast Ratio ◽  
Optical Efficiency ◽  
Full Color ◽  
Led Array ◽  
Conversion Materials ◽  
Low Efficiency ◽  
Color Conversion

Color-converted micro-LED displays consist of a mono-color micro-LED array and color conversion materials to achieve full color, while relieving the burden of epitaxial growth of three-color micro-LEDs. However, it usually suffers from low efficiency and color crosstalk due to the limited optical density of color conversion materials. With funnel-tube array, the optical efficiency of the color-converted micro-LED display can be improved by ~3X, while the crosstalk is eliminated. After optimization of the tapper angle, the ambient contrast ratio is also improved due to higher light intensity.

scholarly journals High-Performance Color-Converted Full-Color Micro-LED Arrays

2020 ◽  
Vol 10 (6) ◽  
pp. 2112 ◽  
Author(s):  
Won Hee Kim ◽  
Young Jae Jang ◽  
Ja-Yeon Kim ◽  
Myungsoo Han ◽  
MinJae Kang ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
High Performance ◽  
Efficient Technique ◽  
Full Color ◽  
Conversion Materials ◽  
Color Conversion ◽  
Led Arrays ◽  
Lithography Technique

Color-converted micro-LED displays consisting of mono-blue-colored micro LED arrays and color-conversion materials have been used to achieve full color while reliving the transfer and epitaxial growth of three different-colored micro LEDs. An efficient technique is suggested to deposit the color-conversion layers on the blue micro LEDs by using a mixture of photo-curable acrylic and nano-organic color-conversion materials through the conventional lithography technique. This study attempts to provide a solution to fabricate full-color micro-LED displays.

scholarly journals High-Uniform and High-Efficient Color Conversion Nanoporous GaN-Based Micro-LED Display with Embedded Quantum Dots

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2696
Author(s):  
Yu-Ming Huang ◽  
Jo-Hsiang Chen ◽  
Yu-Hau Liou ◽  
Konthoujam James Singh ◽  
Wei-Cheng Tsai ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Light Absorption ◽  
Full Color ◽  
Led Array ◽  
High Efficient ◽  
New Type ◽  
Conversion Efficiencies ◽  
Color Conversion ◽  
Scatter Light

Quantum dot (QD)-based RGB micro-LED technology is seen as one of the most promising approaches towards full color micro-LED displays. In this work, we present a novel nanoporous GaN (NP-GaN) structure that can scatter light and host QDs, as well as a new type of micro-LED array based on an NP-GaN embedded with QDs. Compared to typical QD films, this structure can significantly enhance the light absorption and stability of QDs. As a result, the green and red QDs exhibited light conversion efficiencies of 90.3% and 96.1% respectively, leading to improvements to the luminous uniformity of the green and red subpixels by 90.7% and 91.2% respectively. This study provides a viable pathway to develop high-uniform and high-efficient color conversion micro-LED displays.

scholarly journals Use of Recycling-Reflection Color-Purity Enhancement Film to Improve Color Purity of Full-Color Micro-LEDs

2022 ◽  
Vol 17 (1) ◽  
Author(s):  
Zhi Ting Ye ◽  
Jun-Yi Wu
Keyword(s):  
Conversion Efficiency ◽  
High Efficiency ◽  
Color Purity ◽  
Incident Wavelength ◽  
Excitation Light ◽  
Full Color ◽  
Conversion Materials ◽  
Pass Through ◽  
Color Conversion ◽  
Light Conversion Efficiency

Abstract A common full-color method involves combining micro-light-emitting diodes (LEDs) chips with color conversion materials such as quantum dots (QDs) to achieve full color. However, during color conversion between micro-LEDs and QDs, QDs cannot completely absorb incident wavelengths cause the emission wavelengths that including incident wavelengths and converted wavelength through QDs, which compromises color purity. The present paper proposes the use of a recycling-reflection color-purity-enhancement film (RCPEF) to reflect the incident wavelength multiple times and, consequently, prevent wavelength mixing after QDs conversion. This RCPEF only allows the light of a specific wavelength to pass through it, exciting blue light is reflected back to the red and green QDs layer. The prototype experiment indicated that with an excitation light source wavelength of 445.5 nm, the use of green QDs and RCPEFs increased color purity from 77.2% to 97.49% and light conversion efficiency by 1.97 times and the use of red QDs and RCPEFs increased color purity to 94.68% and light conversion efficiency by 1.46 times. Thus, high efficiency and color purity were achieved for micro-LEDs displays. Graphical Abstract

scholarly journals Mini-LED and Micro-LED: Promising Candidates for the Next Generation Display Technology

2018 ◽  
Vol 8 (9) ◽  
pp. 1557 ◽  
Author(s):  
Tingzhu Wu ◽  
Chin-Wei Sher ◽  
Yue Lin ◽  
Chun-Fu Lee ◽  
Shijie Liang ◽  
...  
Keyword(s):  
High Efficiency ◽  
Contrast Ratio ◽  
Consumer Electronics ◽  
Next Generation ◽  
Light Emitting ◽  
Full Color ◽  
Chip Size ◽  
Display Technology ◽  
Main Components ◽  
Color Conversion

Displays based on inorganic light-emitting diodes (LED) are considered as the most promising one among the display technologies for the next-generation. The chip for LED display bears similar features to those currently in use for general lighting, but it size is shrunk to below 200 microns. Thus, the advantages of high efficiency and long life span of conventional LED chips are inherited by miniaturized ones. As the size gets smaller, the resolution enhances, but at the expense of elevating the complexity of fabrication. In this review, we introduce two sorts of inorganic LED displays, namely relatively large and small varieties. The mini-LEDs with chip sizes ranging from 100 to 200 μm have already been commercialized for backlight sources in consumer electronics applications. The realized local diming can greatly improve the contrast ratio at relatively low energy consumptions. The micro-LEDs with chip size less than 100 μm, still remain in the laboratory. The full-color solution, one of the key technologies along with its three main components, red, green, and blue chips, as well color conversion, and optical lens synthesis, are introduced in detail. Moreover, this review provides an account for contemporary technologies as well as a clear view of inorganic and miniaturized LED displays for the display community.

scholarly journals Improved Color Purity of Monolithic Full Color Micro-LEDs Using Distributed Bragg Reflector and Blue Light Absorption Material

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 436 ◽  
Author(s):  
Shao-Yu Chu ◽  
Hung-Yu Wang ◽  
Ching-Ting Lee ◽  
Hsin-Ying Lee ◽  
Kai-Ling Laing ◽  
...  
Keyword(s):  
Blue Light ◽  
Light Absorption ◽  
Bragg Reflector ◽  
Color Purity ◽  
Distributed Bragg Reflector ◽  
Light Emitting ◽  
Full Color ◽  
Conversion Materials ◽  
Bottom Side ◽  
Color Conversion

In this study, CdSe/ZnS core-shell quantum dots (QDs) with various dimensions were used as the color conversion materials. QDs with dimensions of 3 nm and 5 nm were excited by gallium nitride (GaN)-based blue micro-light-emitting diodes (micro-LEDs) with a size of 30 μm × 30 μm to respectively form the green and red lights. The hybrid Bragg reflector (HBR) with high reflectivity at the regions of the blue, green, and red lights was fabricated on the bottom side of the micro-LEDs to reflect the downward light. This could enhance the intensity of the green and red lights for the green and red QDs/micro-LEDs to 11% and 10%. The distributed Bragg reflector (DBR) was fabricated on the QDs color conversion layers to reflect the non-absorbed blue light that was not absorbed by the QDs, which could increase the probability of the QDs excited by the reflected blue light. The blue light absorption material was deposited on the DBR to absorb the blue light that escaped from the DBR, which could enhance the color purity of the resulting green and red QDs/micro-LEDs to 90.9% and 90.3%, respectively.

scholarly journals 39.1: Invited Paper: Organic Color‐Conversion Materials for Full‐Color MicroLED Displays

2021 ◽  
Vol 52 (S1) ◽  
pp. 269-269
Author(s):  
Shou-Cheng Dong ◽  
Yibin Jiang ◽  
Ching W. Tang
Keyword(s):  
Full Color ◽  
Conversion Materials ◽  
Color Conversion

Tetraphenylbenzene-based AIEgens: the Horizontally Oriented Emitters for highly Efficient Non-doped Deep Blue OLEDs and Host for High-Performance Hybrid WOLEDs

2020 ◽  
Author(s):  
Pengbo Han ◽  
Zeng Xu ◽  
Chengwei Lin ◽  
Dongge Ma ◽  
Anjun Qin ◽  
...  
Keyword(s):  
High Performance ◽  
General Strategy ◽  
Flat Panel Displays ◽  
Light Emitting ◽  
Horizontal Orientation ◽  
Deep Blue ◽  
Full Color ◽  
High Emission ◽  
White Oleds ◽  
Low Efficiency

Deep blue organic-emitting fluorophores are crucial for application in white lighting and full color flat-panel displays but emitters with high color quality and efficiency are rare. Herein, novel deep blue AIE luminogens (AIEgens) with various donor units and an acceptor of cyano substituted tetraphenylbenzene (TPB) cores were developed and used to fabricate non-doped deep blue and hybrid white organic light-emitting diodes (OLEDs). Benefiting from its high emission efficiency and high proportion of horizontally oriented dipoles in the film state, the non-doped deep blue device based on CN-TPB-TPA realized a maximum external quantum efficiency 7.27%, with a low efficiency roll-off and CIE coordinates of (0.15, 0.08). Moreover, efficient two-color hybrid warm white OLEDs (CIE<sub>x,y</sub> = 0.43, 0.45) were achieved using CN-TPB-TPA as the blue-emitting layer and phosphor doped host, which realized maximum current, power, external quantum efficiencies 58.0 cd A<sup>-1</sup>, 60.7 lm W<sup>-1</sup> and 19.1%, respectively. This work provides a general strategy to achieve high performance, stable deep blue and hybrid white OLEDs by construction of AIEgens with excellent horizontal orientation

Measurement of hemoglobin oxygen saturation in capillaries

1987 ◽  
Vol 252 (5) ◽  
pp. H1031-H1040 ◽  
Author(s):  
M. L. Ellsworth ◽  
R. N. Pittman ◽  
C. G. Ellis
Keyword(s):  
Light Intensity ◽  
Oxygen Saturation ◽  
Red Blood Cells ◽  
Optical Density ◽  
Blood Cells ◽  
Striated Muscle ◽  
Cheek Pouch ◽  
Retractor Muscle ◽  
Hamster Cheek Pouch

We present a computer-aided videodensitometric method for the determination of oxygen saturation in red blood cells flowing through capillaries of the hamster cheek pouch retractor muscle. The optical density (OD) of red blood cells is determined at two wavelengths. At the first, 431 nm, there is a maximum difference between absorption by oxygen deoxyhemoglobin. At the second, 420 nm, absorption is equal for the two absorbing species (isosbestic wavelength). In capillaries of the retractor muscle a relationship between oxygen saturation (S) and the following OD ratio was obtained as S = -1.71 (OD431/OD420) + 2.20. The error (95% confidence interval) in oxygen saturation associated with a determination of the OD ratio is estimated to be +/- 4.8%. The computerization of the method employs a frame-by-frame analysis of the light intensity over a selected capillary segment. The light intensity waveform along the segment is digitized and the minimum (I) and maximum (I0) light intensities are used to compute an optical density (OD = log10 [I0/I]). These minimum and maximum intensities correspond to the presence and absence of a red blood cell, respectively. The method permits the off-line analysis of videotaped scenes and provides a means of assessing the extent of temporal and spatial heterogeneity of oxygen saturation in selected capillary networks. The method has been developed for use in capillaries in transilluminated striated muscle but should be generally applicable to the measurement of capillary oxygen saturation in other tissues.

scholarly journals Phaeodactylum Trıcornutum Kültürlerinde Biyomas Tahmini

2017 ◽  
Vol 5 (2) ◽  
pp. 182
Author(s):  
Burcu Ak ◽  
Gökhan Tamer Kayaalp ◽  
Oya Işık ◽  
Melis Çelik Güney
Keyword(s):  
Light Intensity ◽  
Chlorophyll A ◽  
Optical Density ◽  
Phaeodactylum Tricornutum ◽  
Dry Matter ◽  
Nitrogen Deficiency ◽  
Regression Equation ◽  
Control Group ◽  
Analysis Method ◽  
The Mathematical Model

Phaeodactylum tricornutum is the microalgae that is known to produce lipid. In this study, it was aimed to estimate the microalgae Phaeodactylum tricornutum dry matter cultured in the conditions of nitrogen deficiency as a stress factor, in outdoor, in photo bioreactors, by using multiple regression analysis method. In this study, diatom Phaeodactylum tricornutum (Bohlin) was cultured medium of which N was reduced by 50% and with 20% inoculation ratio. The light intensity, temperature, optical density and chlorophyll a, were measured daily. The mathematical model was formed for control group and 50 % of the N applied to the group using optical density, temperature, light intensity, chlorophyll a and without chlorophyll a. The regression equation of control group was estimated. The R2 value of control group was found 95.1% and statistically significant. Then, the regression equation was estimated for control group without chlorophyll a. The R2 value of this equation was found 94.0% and statistically significant. And then, the regression equation was estimated in 50% nitrogen. The R2 value of control group was found 92.4% and statistically significant. Finally, the regression equation was estimated in 50% nitrogen deficiency without chlorophyll a. The R2 value of this equation was found 91.7% and statistically significant.

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