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Display Technology, Journal of

Issue 12 • Date Dec. 2013

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Displaying Results 1 - 21 of 21
  • [Front cover]

    Page(s): C1
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  • Journal of Display Technology publication information

    Page(s): C2
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  • Table of contents

    Page(s): 931 - 932
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  • Controlling Power Consumption for Displays With Backlight Dimming

    Page(s): 933 - 941
    Multimedia
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1224 KB) |  | HTML iconHTML  

    Backlight dimming of Liquid Crystal Displays (LCD) is a technology which aims at saving power and improving visual quality. The evolution of energy standards and the increasing public expectations regarding power consumption have made it necessary for backlight systems to manage their power. Such a control is challenging to implement, because for LCD displays quality and power are closely interlinked, and one cannot be modified without affecting the other. To address this issue, we present a framework for power controlled backlight dimming defining some key concepts. Two methods to obtain backlights with a predefined power level for images are presented: one method has low complexity and the other achieves high performance in terms of quality/power trade-off. Those methods are evaluated on a modeled Light-Emitting Diode edge-lit backlight display. The high-performance method performs significantly better than other algorithms from the literature, when considering both calculated power and quality. This high-performance method is then extended to video in three modes. The first mode favors high quality in a power-aware manner and allow significant power variations, the second mode has strict power constraints and the third one provides a trade-off between the other two. View full abstract»

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  • Improving the Performance of a Hybrid Inorganic–Organic Light-Emitting Diode Through Structure Optimization

    Page(s): 942 - 946
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (582 KB) |  | HTML iconHTML  

    Significant performance enhancement of a green hybrid inorganic-organic light-emitting diode (HyLED) based on a simplified WO3/organic layer structure has been achieved through structure optimization. A 20-50 nm as-deposited WO3 layer allowed for facile hole injection and transport. In the meantime, it had high transparency and good robustness required for efficient and reliable operation of the HyLED. Inserting a 30 nm undoped 4,4 '-N,N '-dicarbazolebiphenyl (CBP) layer between the WO3 and emitting layer resulted in a broadened exciton generation zone and improved the brightness by 87.4% at 20 mA/cm2. At this injection level, the optimized HyLED reached a luminance of 11642 cd/m2 and a current efficiency of 58.2 cd/A, and exhibited good reliability under constant-current stressing. View full abstract»

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  • Investigation and Comparison of the GaN-Based Light-Emitting Diodes Grown on High Aspect Ratio Nano-Cone and General Micro-Cone Patterned Sapphire Substrate

    Page(s): 947 - 952
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1132 KB) |  | HTML iconHTML  

    In this paper, we demonstrated the high performance GaN-based LEDs by using a high aspect ratio cone-shape nano-patterned sapphire substrate (HAR-NPSS). We utilized nano-imprint lithography (NIL) and dry-etching system to fabricate a high depth HAR-NPSS. The micro-scale patterned sapphire substrate (PSS) was also used for comparison. A great enhancement of light output was observed when GaN-based LEDs were grown on a HAR-NPSS or a PSS. The light output power of LEDs with a HAR-NPSS and LEDs with a PSS were enhanced of 49 and 38% compared to LEDs with a unpatterned sapphire substrate. The high output power of the LED with a HAR-NPSS indicated that the technology of NAR-NPSS not only can improve the crystalline quality of GaN-based LEDs but also a promising development to a NPSS. View full abstract»

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  • Efficiency Improvement of Short-Period InGaN/GaN Multiple-Quantum Well Solar Cells With {\hbox {H}} _{2} in the GaN Cap Layer

    Page(s): 953 - 956
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (667 KB) |  | HTML iconHTML  

    The thick-well InGaN/GaN short period multiple quantum well solar cells (SCs) with H 2 in the GaN cap layer exhibits an improved open-circuit voltage, fill factor, and conversion efficiency ( η%) compared with those of SCs without the ramped H 2 in the GaN cap layer. The η% of the SC with the ramped H 2 in the GaN cap layer (0.77%) shows a 67.4% improvement compared with that of the SC without the ramped H 2 (0.46%). Furthermore, the η% of SC with patterned sapphire substrate (PSS) (1.36%) indicates a 76.6% improvement compared with that of SC without PSS (0.77%). View full abstract»

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  • A Novel Voltage-Programmed Pixel Circuit Utilizing V_{T} -Dependent Charge-Transfer to Improve Stability of AMOLED Display

    Page(s): 957 - 964
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2775 KB) |  | HTML iconHTML  

    A novel voltage-programmed pixel circuit using hydrogenated amorphous silicon (a-Si:H) thin-film transistors (TFTs) for active-matrix organic light-emitting diode (AMOLED) displays is proposed. The threshold voltage shift (ΔVT) of the drive TFT caused by electrical stress is compensated by an incremental gate-to-source voltage (ΔVGS) generated by utilizing the ΔVT-dependent charge transfer from the drive TFT to a TFT-based metal-insulator-semiconductor (MIS) capacitor. A second MIS capacitor is used to inject positive charge to the gate of the drive TFT to improve the OLED drive current. The non-ideality of the ΔVT-compensation, TFT overlap capacitance, programming speed, and OLED degradation are discussed. The effectiveness of the proposed pixel circuit is verified by simulation results. View full abstract»

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  • Design of a Hybrid Light Guiding Plate With High Luminance for Backlight System Application

    Page(s): 965 - 971
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1120 KB) |  | HTML iconHTML  

    We proposed a novel backlight system, which consisted of a hybrid light guide plate (LGP) and one diffuser sheet. The hybrid LGP contains a flat plate without any microstructures and one layer of optically patterned film (OPF). Comparing with the conventional edge-lit backlight system, the on-axis luminance could be improved to 6.1 × by using the novel backlight system and the half-luminance angle decreased from 21 deg to 10 deg in vertical direction, and decreased from 21 deg to 6 deg in horizontal direction. At the same time, this design also achieved a uniformity of illumination of 89%. The design can predigest the fabrication and reduce the number of components. Moreover, since the microstructures arrangement was periodical, user could use light-emitting diodes (LEDs) on the both sides. When user turned on both side LEDs, the on-axis luminance were improved 1.7 × comparing with turning on single side LEDs. View full abstract»

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  • Stability of Particle Movement in Reflective Electronic Displays by Analysis of the Response Time

    Page(s): 972 - 976
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1058 KB) |  | HTML iconHTML  

    In this study, we propose a measurement system for extracting the response time of negatively and positively charged particles having contrasting colors. The system consists of a laser, a photodiode, a shield box, a power supply, and an oscilloscope. The response times measured by this system are used to analyze the movement of oppositely charged particles, to determine the appropriate driving waveform, and to the filtering voltage of the particle-moving method. The particle-moving method controls the response times and the electrical balance of oppositely charged particles in a panel. View full abstract»

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  • Neutral Point Clamped Inverter Based PDP Driver

    Page(s): 977 - 984
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2460 KB) |  | HTML iconHTML  

    A cost-effective and high-efficiency driver is proposed for plasma display panels (PDPs) by eliminating switching devices with high current ratings. The proposed driver is based on a neutral -point clamped inverter structure, and the path switches can be eliminated without reducing the flexibility in designing driving waveforms. Moreover, the LC resonant operation during the sustain period can be constructed with only unidirectional diodes in aid of the switching scan IC devices. Thus, the proposed driver can produce a PDP driving waveform with no path switches as well as no resonant switches. Since the path switches and the resonant switches are practically implemented with several semiconductor devices in parallel due to high gas-discharge and capacitor displacement current, the proposed driver can considerably simplify the overall driver with fewer semiconductor devices. Additionally, high conduction losses from the path switches and the resonant switches with high current loading can be eliminated in the proposed driver, leading to higher efficiency. The developed driver also places the clamping diodes to recover the inductive energy trapped in the resonant inductors due to the inevitable diode reverse-recovery phenomena. View full abstract»

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  • Channel Length Dependent Bias-Stability of Self-Aligned Coplanar a-IGZO TFTs

    Page(s): 985 - 988
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1092 KB) |  | HTML iconHTML  

    We report channel length L ( L ranging from 2 to 40 μm) dependence of the electrical stability of amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs). The a-IGZO TFTs employ a coplanar structure with a SiNx interlayer used to dope the source/drain regions. After application of positive gate bias stress (PBS), short-channel devices ( L = 2 μm) exhibit smaller threshold voltage shifts ( ΔVth) compared to longer-channel devices ( L ≥ 4 μm). It is proposed that carrier diffusion takes place from the high carrier concentration regions under the SiN interlayer to the intrinsic channel region, thereby shifting the Fermi level closer to the conduction band. Higher Fermi levels mean less defect states available for carrier trapping - hence the small ΔVth in short devices under PBS. View full abstract»

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  • Synthesis and Characterization of Sm ^{3+} –Yb ^{3+} Codoped Y _{2} O _{3} Phosphor

    Page(s): 989 - 994
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1637 KB) |  | HTML iconHTML  

    The Y2O3 phosphors doped/codoped with Sm3+/Sm3+-Yb3+ ions at different concentrations have been prepared using combustion technique. The prepared phosphors are characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The average crystallite size of the phosphors calculated based on the XRD is observed to increase with annealing. The FTIR analysis suggested that the impurity is reduced on annealing the sample. NIR to visible frequency upconversion emission has been observed from synthesized phosphors upon a 980 nm diode laser excitation. The concentration dependence study shows a tuning in light color emitted from samples. The upconversion mechanism involved in the Sm3+/Sm3+-Yb3+ doped/codoped Y2O3 phosphors has been explained on the basis of excited state absorption (ESA) and energy transfer (ET) process. View full abstract»

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  • Design and Optimization of 2D Laser Source Module for Compact Projector

    Page(s): 995 - 1000
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (954 KB) |  | HTML iconHTML  

    In order to make projector compact and efficient, we propose that the 2D laser source module is consisted of VCSEL array and micro-lens array. It describes packaging structure design of VCSEL array and thermal resistance calculation. A thermal 3D analysis of 3 ×3 array based on the finite-element method (FEM) is presented. The analysis shows that the maximum internal temperature of a VCSEL array reaches 51°C. Then, it describes the principle of the micro-lens array. By ZEMAX simulation, in the micro-lens array illumination system, we have got the energy efficiency 67.3%, the light uniformity is 95.5%, respectively, on the micro-display chip at the distance of 65 mm. We have successfully built the complete 3-LCOS projection system based on the 2D source module. It can provide 1362 lm D65 light, and its total volume is 260 × 200 × 160 mm3 which is more compact than the commercial projector. View full abstract»

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  • Transparent Current Mirrors With a-GIZO TFTs: Neural Modeling, Simulation and Fabrication

    Page(s): 1001 - 1006
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1389 KB) |  | HTML iconHTML  

    This paper characterizes transparent current mirrors with n-type amorphous gallium-indium-zinc-oxide (a-GIZO) thin-film transistors (TFTs). Two-TFT current mirrors with different mirroring ratios and a cascode topology are considered. A neural model is developed based on the measured data of the TFTs and is implemented in Verilog-A; then it is used to simulate the circuits with Cadence Virtuoso Spectre simulator. The simulation outcomes are validated with the fabricated circuit response. These results show that the neural network can model TFT accurately, as well as the current mirroring ability of the TFTs. View full abstract»

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  • IEEE Open Access Publishing

    Page(s): 1007
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  • IEEE Xplore Digital Library

    Page(s): 1008
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  • 2013 List of Reviewers

    Page(s): 1009 - 1013
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  • 2013 Index Journal of Display Technology Vol. 9

    Page(s): 1014 - 1039
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  • Journal of Display Technology information for authors

    Page(s): C3
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  • [Blank page - back cover]

    Page(s): C4
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Aims & Scope

This publication covers the theory, design, fabrication, manufacturing and application of information displays and aspects of display technology.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Arokia Nathan
University of Cambridge
Cambridge, U.K.