한국정보디스플레이학회:학술대회논문집
The Korean Infomation Display Society (KIDS)
- Annual
Domain
- Electricity/Electronics > Display
2007.08b
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Thin Beam Excimer Laser Annealing is investigated as one possible process enabled by the variable concept of Thin Beam LTPS processing. The structure of the resulting p-Si material is analyzed in terms of grain size distribution, scaling with energy density and overlap, as well as average surface roughness. This process provides similar control and latitude as conventional excimer laser annealing, but reduced average surface roughness and the potential to be scaled to significant productivity levels.
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Electrical instabilities in p-channel polysilicon TFTs: role of hot carrier and self-heating effectsThe effects of hot carriers and self-heating on the electrical stability of p-channel TFTs have been analysed combining experimental data and numerical simulations. While hot carrier effects were shown not to induce appreciable degradation, self-heating related instability was found to more seriously affect the device characteristics. New models have been developed to explain the reported results.
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Park, Soo-Jeong;Lee, Seok-Woo;Baek, Myoung-Kee;Yoo, Yong-Su;Kim, Chang-Yeon;Kim, Chang-Dong;Kang, In-Byeong 1071
6Mask CMOS process in low temperature polycrystalline silicon thin film transistors (poly-Si TFTs) has been developed and verified by manufacturing a 6Mask CMOS AMLCD panel. The novel 6Mask CMOS process is realized by eliminating the storage mask, gate mask and via open mask of conventional structure. -
Negative Bias Temperature Instability (NBTI) in Eximer Laser Annealing (ELA) based Low Temperature polysilicon (LTPS) Thin-Film Transistors (TFT) was investigated. Even though NBTI is generally appeared in devices with thin gate oxide, the TFT with gate oxide thickness of 120 nm, relatively thick, also showed NBTI effect and dynamic NBTI effect is dependent on operational frequency.
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System on Panel (SOP) can integrate many functions by Thin Film Transistor (TFT) circuits on an insulator substrate without using external driver LSIs. However, to make practical SOP has become more and more difficult because of rapid cost reduction of the driver LSIs. This paper will review the circuit design technology trend for SOP and introduce an example of a practical SOP, 2.0inch QVGA full color active matrix OLED with 8bit source driver.
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A new DC-DC converter was designed for gate driver circuit using low temperature poly-Si TFT technology. To achieve high efficiency and small area, we proposed a cross-coupled type DC-DC converter which converts 5V of input voltage to 9V of output voltage and supplies 120
$\mu$ A of current to load. Its efficiency is 92.9% and the area is reduced as much as 19% compared to the previously reported latch type DC-DC converter. -
New display technologies including LCD and plasma panels and Digital Light Projection (DLP) systems all offer large screens and impressive picture quality. However, flat-panel displays require a sophisticated picture processing to let these panels perform at their optimum levels. This paper explains why motion compensating techniques combined with frame rate conversion and quasi-impulse driving reduces motion blur and film judder for flat panel displays and presents the IC and its system application using this technique.
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This paper reviews the state of the art of critical processes and proposes novel structures of an integrated device comprising LCD and OLED backlight that increases the compactness and decreases the assembly time of hand-held mobile display units like the hand-sets of mobile phones
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Ruhstaller, Beat;Flatz, Thomas;Moos, Michael;Kiy, Michael;Beierlein, Tilman;Kern, Roland;Winnewisser, Carsten;Pretot, Roger;Chebotareva, Natalia;Schaaf, Paul Van Der 1099
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Highly efficient organic electroluminescent devices (OLEDs) based on 4,7- diphenyl-1, 10- phenanthroline (BPhen) as the electron transport layer (ETL), tris (8-hydroxyquinoline) aluminum (
$Alq_3$ ) as the emission layer (EML) and N,$\acute{N}$ -bis-[1-naphthy(-N,$\acute{N}$ diphenyl-1,1´-biphenyl-4,4´-diamine)] (NPB) as the hole transport layer (HTL) were developed. The typical device structure was glass substrate/ ITO/ NPB/$Alq_3$ / BPhen/ LiF/ Al. Since BPhen possesses a considerable high electron mobility of$5\;{\times}\;10^{-4}\;cm^2\;V^{-1}\;s^{-1}$ , devices with BPhen as ETL can realize an extremely high luminous efficiency. By optimizing the thickness of both HTL and ETL, we obtained a highly efficient OLED with a current efficiency of 6.80 cd/A and luminance of$1361\;cd/m^2$ at a current density of$20\;mA/cm^2$ . This dramatic improvement in the current efficiency has been explained on the principle of charge balance. -
Kim, Hyun-Jong;Kim, Su-Hwan;Chang, Seung-Wook;Lee, Dong-Kyu;Jeong, Dong-Seob;Chung, Ho-Kyoon;Hong, Yong-Taek 1108
OLED driving voltage shift can reduce the OLED display lifetime, especially for digitally driven AMOLED. By operating OLED at high frequency, we were able to suppress OLED voltage shift degradation, expecting improved AMOLED lifetime. We describe frequency dependence of voltage shift obtained from bias stress test of OLED. -
Kim, Mu-Gyeom;Kim, Sang-Yeol;Lee, Sung-Hun;Song, Jung-Bae;Park, Sang-Hun;Son, Jhun-Mo;Kang, Sung-Kee;Tamura, Shinichiro 1112
Optical thickness method using double interferometer showed dynamic variations of both mechanical and optical thicknesses. Packing density measured a thickness ratio of before and after pressed single film. Lower swelled thickness of emitting layer in a device and densely packed film had shown better lifetime. -
Nano-sized metal patterns were successfully fabricated on flexible PET substrate using nanoimprint lithography. 70nm line and space PMMA resist pattern was formed on PET substrate without residual layer by 'artial filling effect' and 20nm thin Cr metal layer was deposited by e-beam evaporation. Then, PMMA resist was selectively removed by acetone and 70nm narrow Cr pattern was formed.
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Canisius, Johannes;Brookes, Paul;Heckmeier, Michael;James, Mark;Mueller, David;Patterson, Katie 1121
Ink jet printing has been targeted as a key technology for OLED, TFT backplane and other organic semiconductor device fabrication. This presentation will concentrate on aspects of the IJ process, formulation design, jetting performance, interaction with the substrate and resultant printed device performance. -
The laminating technique for developing flexible liquid crystal display was demonstrated by using a thin UV curable polymer film and a plastic substrate with patterned polymer wall structure. We adopted the rigid wall structure to provide a solid mechanical support for the stable molecular alignment of liquid crystals (LCs) in the device. The cover film was prepared to have an ability of aligning LC molecules by patterning a micro-groove structure using the soft-lithographic process. These two substrates can be assembled tightly by the laminating and one-step UV irradiation process because of the adhesive nature of the used UV curable polymers. Proposed method can be used to fabricate the flexible LC display with simplicity and also be applicable for a cost-effective roll-to-roll process.
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To prevent biological influence of images upon viewers, we investigated the characteristics features of images and of viewing environments which can cause photosensitivity seizures and visually-induced motion sickness, and developed some methods of detection and conversion of images that can cause such influence.
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This paper presents motion picture artifacts measured with a high-speed camera. Measurement results of the high-speed camera on moving targets will be evaluated and compared with motion blur data derived from step responses measured on stationary test patterns with a spot-photodetector.
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In this paper, an image enhancement method by saturation and contrast improvement is proposed. Histogram equalization with color difference makes higher contrast. By generating saturation amplification ratio with color difference, the saturation improves effectively. The experimental results show that the proposed algorithm has higher contrast and more natural - look than the conventional methods.
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We carried out the human visual evaluation on PDPs and LCDs to clarify the viewer preference and the related physical and physiological factors. In the subjective evaluation, the impression test using the semantic differential method was carried out. In the objective evaluation, the eye motion tracking system was used. Our study showed that considering the real usage, the optimum display for viewers was that which showed more soft and smooth image without blurring.
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As a follow-up to our previous work we present in this paper some experimental results on LED light recycling. Specifically we demonstrate for the first time that screen brightness can be increased using our light pipe based light recycling scheme for reallife projection display applications.
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The distributions of mercury (Hg) in the bulb of a mercury vapor lamp are significantly affected by its turn-off conditions. Most of mercury should be attached to the electrodes before ignition by a proper turn-off condition. In the present study, the effect of the transient profiles of lamp cooling after turn-off on the distribution of Hg was investigated.
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To reduce acoustic noise level of an AV projector, primary noise sources of AV projector were analyzed. Based on the analyzed result, methods to control each source are presented and tried. Structure-borne noise can be controlled by anti vibration design of mounting system, and air-borne noise by reducing flow resisitvity.
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We have developed
$16{\mu}m{\times}16{\mu}m$ digital micromirror array suitable for seamless-picture projection display system. This structure can improve the picture quality by making seamlesspicture image when combined with high-fill-factor microlens array to focus lights onto the mirror center. The fabricated micromirror shows excellent dynamic performances including the resonant frequency of 400 kHz. -
Delta doping method can separate the threshold voltage control region from the charge transport region in a-Si TFT, whereby the threshold voltage of a TFT could be modified. Threshold voltage could be changed by delta doping, while field effect mobility was estimated to be 80% of that of standard TFT.
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Integrating systems on TFT-LCD panels is more and more popular for the mobile display application. However, it may not be necessary to use LTPS TFT devices. A-Si TFTs are used to integrate systems on TFT-LCD panels, especially scan (gate) drivers. To further reduce the chip size of driver IC, the triplegate pixel structure is developed. Therefore, the number of the source lines is reduced to 1/3 times.
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We have investigated the threshold voltage shifts(
${\Delta}Vth$ ) and drain current level shift (${\Delta}Ids$ ) in subthreshold region of a-Si:H TFTs induced by DC Bias (Vgs and Vds) - Temperature stress (BTS) condition. We plotted the transfer curves and the${\Delta}Vth$ contour maps as Vds-Vds stress bias and Temperature to examine the severe damage cases on TFTs. Also, by drawing out the time-dependent transfer curve (Ids-Vgs) in the region of$10^{-8}\;{\sim}\;10^{-13}$ (A) current level, we can estimate the failure time of TFTs in a operating condition. -
A novel integrated a-Si:H gate driver with high reliability has been designed and simulated. Since the a-Si:H TFT is easily degraded by gate bias stress, we should optimize the circuit considering the threshold voltage shift. The conventional circuit shows voltage drop at the input stage by threshold voltage of the TFT, however, the proposed circuit dose not shows voltage drop and keeps constant regardless of threshold voltage shift of the TFT.
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The new self-priming addressing driving scheme was proposed to improve an address discharge time lag. It utilizes the priming effect maintaining the priming ramp discharge during an address period and the address discharge time lag is significantly improved. In this study, the basic characteristics of the priming ramp discharge are presented.
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The address discharge characteristics by the various scan-low and common-bias voltages are investigated based on measured address discharge time lags and
$V_t$ close-curve analysis. The scan-low voltages are changed under the same voltage difference between the X and Y electrodes during an address period. As the voltage difference between the scan and address electrodes is increased during an address period, the address discharge time lag is shortened but the background luminance is increased. It is found that the improved address discharge characteristics is caused by the effect of the higher external applied voltage during an address period than the accumulated wall charges during a reset period and the high background luminance can be prevented by applying an address-bias voltage during a rising-ramp period and low reset voltage. -
Jang, Jin-Ho;Lee, Don-Kyu;Ok, Jung-Woo;Kim, Deok-Won;Kim, Dong-Hyun;Lee, Hae-June;Lee, Ho-Jun;Par, Chung-Hoo 1189
We propose new driving schemes, asymmetry and long gap mode, of PDP having auxiliary electrode between scan and common electrode. For the asymmetric modes, the auxiliary electrode located nearly center of the primary electrodes is connected to the scan of common electrode during all periods of reset, address and sustain. For the long gap mode, it is electrically disconnected or maintained at dc voltage of Vs/2 during sustain period except the first several sustain pulses. The proposed structure and driving method can provide higher luminous efficacy by minimizing consumption energy. The effectiveness of the new driving schemes has been investigated for various Xe partial pressure conditions. -
A new planar transformer type energy recovery circuit for PDP is proposed in this paper. The same current is transferred through both the primary and secondary sides during the energy recovery period. The conduction loss is reduced. Fabrication through simple manufacturing processes is possible using the PCB winding.
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The improvement of the electron injection is of critical importance for obtaining efficient and stable organic light-emitting diodes(OLEDs). Here, we report some of our recent results on the development of new cathode interlayer materials for OLEDs. Some of our new materials show performance superior to that of LiF.
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Confinement of charge carrier and exciton is the essential factor for enhancing the efficiency and stability of the electrophosphorescent devices. The interplay between the properties of emitters and other adjacent layers are studied based on the physical interpretation with difference of energy level, charge carrier mobility, and corresponding charge-trapping behavior.
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Kathirgamanathan, Poopathy;Arkley, Vincent;Surendrakumar, S.;Paramaswara, G.;Ganeshamurugan, S.;Antipan-Lara, J.;Ravichandran, S.;Kumaraverl, M.;Chan, Y.F. 1206
Both PM-OLEDs and AM-OLEDs are now in production. However, manufacturers are still concerned about life-time, voltage drift, operating voltage and efficiency in order to develop larger displays. Most material suppliers seem to be focussing on emitters and the benefits of introducing suitable charge transporters have been largely unexplored. OLED-T has developed a novel organic electron injector (Trade Name: EI-101) which evaporates at a very low temperature of$300^{\circ}C$ as opposed to the conventional LiF which requires$580^{\circ}C$ . EI-101 has been found to increase the lifetime by up to 12%, reduce the voltage drift by up to 61% and increase the efficiency by up to 15%. The material can be handled in air and in situ Q-mass spectroscopy on extended thermal evaporation has confirmed its high stability for use in mass production. -
The OTFT technologies have been mature almost up to the level of commercialization. In this paper we report the OTFT's applications to the backplane for active matrix electrophoretic, active matrix OLED and to integrated circuits. In addition we also introduce the recently developed technologies for reduction of OTFT's operating voltage.
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We have been developing printed organic TFTs for flexible displays. In this study, we have pay attention to the operation stability improvement of the organic TFTs, and studied several factors especially depending on the dielectric layers. From the detailed analysis of the effects of dielectric layers, we have proposed a new printed dielectric layer which is mainly consisting of metal oxide and gives high operation stability
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Kim, Doo-Hyun;Kim, D.W.;Kim, K.S.;Moon, J.S.;KIM, H.J.;Kim, D.C.;Oh, K.S.;Lee, B.J.;You, S.J.;Choi, S.W.;Park, Y.C.;Kim, B.S.;Shin, J.H.;Kim, Y.M.;Shin, S.S.;Hong, Mun-Pyo 1220
The effects of plasma damages to the organic thin film transistor (OTFT) during the fabrication process are investigated; metal deposition process on the organic gate insulator by plasma sputtering mainly generates the process induced damages of bottom contact structured OTFTs. For this study, various deposition methods (thermal evaporation, plasma sputtering, and neutral beam based sputtering) and metals (gold and Indium-Tin Oxide) have been tested for their damage effects onto the Poly 4-vinylphenol(PVP) layer surface as an organic gate insulator. The surface damages are estimated by measuring surface energies and grain shapes of organic semiconductor on the gate insulator. Unlike thermal evaporation and neutral beam based sputtering, conventional plasma sputtering process induces serious damages onto the organic surface as increasing surface energy, decreasing grain sizes, and degrading TFT performance. -
This paper describes recent advances in the R&D work achieved at Fraunhofer HHI (Germany) that are believed to provide key technologies for the development of future human-machine interfaces. The paper focus on the area of vision based interaction technologies that will be one essential component in future three-dimensional display systems.
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This paper presents the overview of 3D video processing technologies for 3DTV such as 3D content generation, 3D video codec and video processing techniques for 3D displays. Some experimental results for 3D contents generation are shown in 3D mixed reality and 2D/3D conversion.
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There are several researches on 2D gaze tracking techniques to the 2D screen for the Human-Computer Interaction. However, the researches for the gaze-based interaction to the stereo images or 3D contents are not reported. This paper presents a gaze-based 3D interaction technique on autostereoscopic display system.
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In this paper, we present a tiled display system for tangible meeting. We built our system as a distributed system and use GPU based warping and image blending technique for real-time processing. For efficiency, we update specific area only, where the remote user exist, in real-time and blended it with static panoramic image of remote site.
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Pribat, Didier;Cojocaru, Costel;Gowtham, M.;Eude, L.;Balan, A.;Bondavalli, P.;Legagneux, P. 1245
We propose new approaches to thin film transistor fabrication that use carbon nanotubes and semiconductor nanowires as active elements. These nanomaterials which are essentially studied in the context of the post CMOS era will certainly impact the active matrix display industry in the near future. -
Ko Park, Sang-Hee;Hwang, Chi-Sun;Byun, Chun-Won;Ryu, Min-Ki;Lee, Jeong-Ik;Chu, Hye-Yong;Cho, Kyoung-Ik;Chae, Jang-Youl;Han, Se-Jin 1249
We have fabricated 3.5” transparent AM-OLED panel driven by PEALD grown ZnO TFT. The performance of ZnO thin film transistor was improved by adapting top gate structure, protection layer for ZnO from photolithography process, optimizing temperature and plasma power of ZnO growth process. The ZnO-TFT has a mobility of$8.9cm^2/V.s$ , a subthreshold swing of 0.95V, and an on/off ratio of$10^7$ . -
Son, Seung-Hyun;Nam, Mun-Ho;Kim, Jung-Min;Cho, Sung-Hee;Jang, Sang-Hun;Kim, Gi-Young;Han, In-Su;Kim, Dae-Hyun;Cho, Young-Mi;Kim, Chang-Wook;Park, Hyoung-Bin 1253
A display device combining plasma display panel (PDP) and field emission display (FED) is proposed to achieve high luminous efficiency. The device can avoid the main energy loss channels of both PDP (ion loss) and FED (low CL efficiency).$2{\sim}6$ ”-diagonal test panels with carbon nano-tube (CNT) electron emitter and Xenon ambient gas showed the luminous efficiency of 4.14lm/W and brightness of$263cd/m^2$ at 35V (1kHz, 1% duty), indicating that it is a good candidate for the low voltage driven, highly efficient next generation display. -
Song, Jin-Won;Yoon, Yeo-Hwan;Kim, Joon-Dong;Lee, Eung-Sug;Choi, Byung-Sam;Kim, Jae-Ho;Han, Chang-Soo 1257
A single-wall carbon nanotube (SWNT) transparent conductive film (TCF) was fabricated using a simple inkjet printing method. The TCF could be selectively patterned by controlling the dot size to diameters as small as$34\;{\mu}m$ . In this repeatable and scalable process, we achieved 71% film transmittance and a resistance of 900 ohm/sq sheet with an excellent uniformity, about${\pm}\;5%$ deviation overall. Inkjet printing of SWNT is substrate friendly and the TCF is printed on a flexible substrate. This method of fabrication using direct printing permits mass production of TCF in a large area process, reducing processing steps and yielding low-cost TCF fabrications on a designated area using simple printing. -
The electrical characteristics of low temperature poly-Si (LTPS) thin-film transistors (TFT) with channel parallel and perpendicular to the direction of lateral growth were studied. The poly-Si film was crystallized using sequential lateral solidification (SLS) laser crystallization technique. The channel orientation dependent turn-on characteristics were investigated by using gated-diodes and capacitance-voltage measurements
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Polycrystalline silicon (poly-Si) films were prepared directly on plastic substrates at a low (<
$200^{\circ}C$ ) by using Catalytic Chemical Vapor Deposition (Cat-CVD) technique without subsequent annealing steps. Surface roughness of the poly-Si layer and the density of the gate dielectric layer were found to be influential to the TFT performance. -
Jung, Keum-Dong;Kim, Yoo-Chul;Kim, Byeong-Ju;Park, Byung-Gook;Shin, Hyung-Cheol;Lee, Jong-Duk 1270
Analytic equations are derived from physical quantities in the gate-source overlap region and the concept of effective gate-source overlap length is proposed. The effective overlap length can be affected by gate voltage, insulator thickness and semiconductor thickness, and the overlap length should be larger than the length to obtain maximum driving current. -
We provide a newly developed dry etching process for the fabrication of ZnO-based oxide TFTs. The etching characteristics of ZnO (active layer) and
$Al_2O_3$ (gate insulator) thin films were systematically investigated when the etching gas mixtures and their mixing ratios were varied in the heliconplasma etching system. -
Jin, Beop-Jong;Hong, Won-Eui;Lim, Jung-Yoon;Kim, Deok-Hoi;Uemoto, Tstomu;Kim, Chi-Woo;Ro, Jae-Sang 1277
Isothermal activation annealing was carried out using boron doped SLS poly-using an RTA system. We observed different behavior of reverse annealing depending on the implantation conditions. -
Son, Hyuk-Joo;Kim, Jae-Hong;Jung, Sung-Wook;Lee, Jeoung-In;Jang, Kyung-Soo;Chung, Hok-Yoon;Choi, Byoung-Deog;Lee, Ki-Yong;Yi, Jun-Sin 1281
In this paper, the properties of n-channel poly-Si TFTs with different channel widths are reported. Poly-Si fabricated using ELA on glass substrates has high quality as a material for applications such as TFT-LCDs. The fabricated n-channel TFTs have a double stack structure of oxide-nitride which acts as an insulator layer. The results show that the small channel TFTs exhibited a lower$V_{TH}$ and the wide channel TFTs had a higher$I_{DSAT}$ . The nchannel poly-Si TFTs with an$I_{ON}/I_{OFF}$ value of more than$10^4$ can be reliable switching devices for AMOLED displays. -
Lee, Kwang-Soo;Jung, Sung-Wook;Kim, Kyung-Hae;Jang, Kyung-Soo;Hwang, Sung-Hyun;Lee, Jeoung-In;Park, Hyung-Jun;Kim, Jae-Hong;Son, Hyuk-Joo;Yi, Jun-Sin 1284
Titanium dioxide ($TiO_2$ ) is promising candidate for fabricating blocking layer of gate dielectrics in non-volatile memory (NVM). In this work, we investigated$TiO_2$ as high dielectric constant material instead of silicon dioxide ($SiO_2$ ), which is generally used as blocking layer for NVM. -
We investigated the effect of Cr thickness on the electrical properties of triisopropylsilyl pentacene organic thin-film transistor (OTFT) employing suspended source-drain electrode. With Cr thickness of 10 nm, the field-effect mobility, on/off ratio and subthreshold slope were
$0.017\;cm^2/Vs$ ,$8.78\;{\times}\;10^3$ and 10 V/decade, respectively. By increasing the Cr thickness to 100 nm, the fieldeffect mobility was increased to$0.032\;cm^2/Vs$ , on/off ratio to$1.12{\times}10^5$ and subthreshold slope to 1 V/decade. -
Kim, Hye-Min;Park, Jae-Hoon;Bong, Kang-Wook;Kang, Jong-Mook;Lee, Hyun-Jung;Han, Chang-Wook;Choi, Jong-Sun 1292
In this report, the effects of chemical surface treatments of ITO gate electrodes of OTFTs have been studied by using acid and base solutions. As a result, it is observed that the threshold voltage of OTFTs could be influenced and modified by the surface treatments. The device with an ITO gate electrode surface-treated by a base solution shows the lowest threshold voltage of -7.66 V, while the threshold voltages are about -13.51 V and -15.3 V for the devices without a surface treatment and with the acid solution treatment, respectively. It is thought that the work function of ITO electrode surface might be affected by the surface treatments, thereby influencing the threshold voltage. -
Bong, Kang-Wook;Park, Jae-Hoon;Kang, Jong-Mook;Kim, Hye-Min;Lee, Hyun-Jung;Yi, Mi-Hye;Choi, Jong-Sun 1295
In this study, we report that the characteristics of OTFTs can be improved by the UV exposure of the surface of the synthesized photo-reactive gate insulator, and be optimized by controlling the exposure time. As a gate dielectric, the modified PVP was prepared by substituting hydroxyl group in PVP with cinnamoyl group. The synthesis details and the effects of the modified PVP on the device performance are discussed. -
Choi, Jong-Kwon;Baik, Min-Kyung;Joo, Min-Ho;Park, Kyu-Ho;Lee, Jay-Man;Kim, Myung-Seop;Yang, Joong-Hwan 1298
The interface between SiNx and ZnO was investigated with Near Edge X-ray Absorption Fine Structure (NEXAFS) for ZnO based thin film transistor (TFT) applications. Impurity species were interstitial$N_2$ molecules at the SiNx / ZnO interface. The evolution of$N_2$ is decreased with increasing of anneal temperature. -
We have investigated degradation of short channel n-type poly-Si TFTs with LDD under high gate and drain voltage stress due to self-heating. We have found that the threshold voltage of short channel TFT is shifted to negative direction on the selfheating stress, whereas the threshold voltage of long channel is moved to positive direction.
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Kim, Sam-Soo;Kim, Min-Soo;Choi, Gyu-Seok;Kim, Heon-Gon;Kim, Yong-Bae;Lee, Dong-Gu;Roh, Jae-Seong 1305
We show that the electrical properties of organic thinfilm transistors(OTFTs) can be enhanced by controlling the morphology of interface between screen printed electrodes and gate dielectrics. Modified surface of the insulator layer($SiO_2$ ) affect on the interface energy of electrode on$SiO_2$ layer. Contact angle measurement and FT-IR spectrum shows that the interface is properly modified. OTFTs device with high efficiency has been realized through modification of interface layer. -
Leakage current produced by backside illumination on bottom-gated amorphous silicon thin film transistor has been investigated. The experimental results show that the leakage current of bottomgated structure is significantly dependent on the shape of amorphous silicon pattern. A proper design of amorphous silicon pattern has been suggested in viewpoint of reducing the leakage current as well as mass production.
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The effect of gate insulator surface treatment on electrical characteristics of bottom contact (BC) and suspended source/drain (SSD) organic thinfilm transistors (OTFTs) was studied. Triisopropylsilylethynyl pentacene was used as an active material and was printed by ink-jet printing method. In case of the BC OTFTs, threshold voltage was shifted from positive to near zero, and the fieldeffect mobility was increased when the gate insulator surface was treated with hexamethyldisilazane. However, in case of SSD OTFT, threshold voltage shift was not observed and the field-effect mobility was decreased.
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Hafnium dioxide nano film as gate insulator for organic thin film transistors is prepared by atomic layer deposition. Mostly crystalline of
$HfO_2$ films can be obtained with oxygen plasma and with water at relatively low temperature of$150^{\circ}C$ .$HfO_2$ was deposited as a uniform rate$1.2A^{\circ}/cycle$ . The morphology and performances of OTFT will be discussed. -
Weng, Chien-Sen;Chao, Chih-Wei;Tseng, Hung Wei;Peng, Chia-Tien;Lin, Kun-Chih;Gan, Feng-Yuan 1319
Planar PIN photodiode is compatible with LTPS process, and its fabrication requires no additional manufacturing process. In this study we design the optimum dimension of PIN diodes with two nitride layers to improve the efficiency of PIN diodes. The PIN photo sensor shows very good sensitivity to ambient light illuminance. -
You, Bong-Hyun;Lee, Jun-Pyo;Kim, Dong-Gyu;Park, Jin-Ho;Kim, Yun-Jae;Berkeley, Brian H.;Kim, Sang-Soo 1323
A new driving method employing 2-dimensional spatial averaging is proposed. This method successfully eliminates the vertical line artifact caused by luminance difference from unbalanced charging voltage between polarities. This spatial averaging method can secure charging time, minimize driver heating, and achieve higher display quality. -
Choo, Kyo-Seop;Kang, Hee-Kwang;Yu, Jun-Hyeok;Do, Mi-Young;Choo, Kyo-Hyuck;Lee, Deuk-Su;Kang, In-Byeong;Chung, In-Jae 1327
We developed a 4 inch (qVGA, 320x240) a-Si TFT LCD which has the function of color scanner. We have designed the novel pixel structure and got good scanning quality with minimum aperture loss. In this new pixel, the sensor capacitance was increased in double without decreasing the aperture loss. -
We have newly developed transflective LCDs with a specific sub-pixel and the single cell gap structure. In our structure, the overall transmittance and reflectance has become higher than typical transflective LCDs. Furthermore, it can simplify the fabrication process of the transflective LCDs.
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Baik, Min-Kyung;Joo, Min-Ho;Choi, Jong-Kwon;Park, Kyu-Ho;Sung, Myeon-Chang;Lee, Ho-Nyun;Kim, Hong-Gyu 1333
We studied the surface defects and the current distributions of ITO thin films by reflected electron energy loss spectroscopy (REELS) and conductiveatomic force microscope (c-AFM). The ohmic behavior of ITO thin film was observed at$230\;^{\circ}C$ annealed sample. The defects related to the electronic structure decreased after anneal process. -
Since organic thin film transistor (OTFT) provides simple and low cost processes, its application to the OTFT display has been studied. We developed an RC oscillator using organic thin film transistor and inverters with bootstrapping transistors. Device parameters were optimized by the simulation and OTFT RC oscillators were fabricated. The oscillator frequency and its dependence on resistance and bias voltage were studied. The organic TFT is adequate for low cost and simple process integrated circuits. The frequency of oscillation was simulated and measured. It is acceptable for low-cost microelectronic device and flat panel displays.
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We have simultaneously fabricated LTPS TFTs and integrated photodiodes on the same glass substrates without any additional LTPS process. The structure of an integrated photodiode is a lateral p-i-n diode with a gate. The performances of a photodiode were improved at a negative gate voltage.
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We have fabricated bottom gate TFTs with active layers of amorphous/microcrystalline Si double layers (DL). Dynamic electric stresses were applied to DL TFTs and a-Si TFTs to compare their degradation characteristics. The DL TFTs were more stable under dynamic stresses than a-Si TFTs.
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We demonstrated that the threshold voltage shift owing to a gate-bias stress is originated from the trapped charges at the interface between semiconductor layer and dielectric layer, and such drawback can be settled by applying long-term delay time to the gate electrode.
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An new green phosphor,
$(Y,Gd)Al_3(BO_3)_4$ :Tb was synthesized by flux assisted solid reaction and its VUV excitation and emission characteristics were examined. The luminance of$(Y,Gd)Al_3(BO_3)_4$ :Tb at 147 nm excitation was higher than that of$YBO_3:Tb$ , while keeping the spectra and decay time of Tb ion same as those of$YBO_3:Tb$ . -
Woo, Chang-Min;Kim, Duck-Gon;Kim, Dong-Ju;Song, Gab-Deuk;Kim, Soon-Hak;Cho, Ho-Young;Lee, Yoon-Soo;Park, Lee-Soon 1360
The bus electrode is composed of two layers. One is the black matrix(BM) and silver layer is formed on top of black layer. The BM paste is made by mixing$Co_3O_4$ black powder with photosensitive vehicle and rheological additives. In this work we studied the effect of$Co_3O_4$ black powder and glass frit on the rheological property of photosensitive BM paste. We also examined how the size and content of black powder and glass frit affect the transmittance and reflectance of the BM layer after sintering. -
Kim, Dong-Ju;Kim, Duck-Gon;Woo, Chang-Min;Ryu, Sueng-Min;Yang, Dong-Yol;Kim, Soon-Hak;Park, Lee-Soon 1364
In this study, the effect of binder polymer on the photolithographic patterning of barrier ribs was studied from view point of polymer structure and barrier rib pattern. -
Laser-ablated ITO patterns showed the formation of shoulders at the edge of the ITO lines and a ripple-like structure of the etched bottom. When the laser ablation was applied in the fabrication of PDP panel, the laser-ablated ITO patterns showed a higher sustaining voltage than that of chemically wet-etched ITO.
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MgO thin films were deposited by
$O^+$ IBAD method and results showed assisting oxygen ion beam energy plays a significant role in characteristics of MgO thin films. The lowest firing inception voltage, the highest brightness and the highest luminous efficiency were obtained when oxygen ion beam energy was 300 eV. -
The effects of the MgO fabrication process on the properties of AC-PDPs were examined. MgO films were deposited by e-beam evaporation with various substrate temperatures and oxygen flow rates. MgO films were analyzed by XRD, CL and ellipsometer. Panel properties such as luminance, efficiency, discharge voltage and discharge delay time were measured with test panels. MgO films with higher temperature, smaller oxygen flow rate showed shorter discharge delay time. Also they showed smaller XRD peak intensity. These results revealed that the discharge delay time was strongly influenced by temperature and oxygen flow rate of the MgO fabrication process.
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The secondary electron emission coefficient (
${\gamma}$ ) of the cathode is an important factor for improving the discharge characteristics of AC-PDP, because of its close relationship to discharge voltage. In this experiment, we have investigated the electronic structure of the energy band in the MgO layer responsible for the high${\gamma}$ . We used three kinds of MgO pellet that have another component, and each MgO layers have been deposited by electron beam evaporation method. The work-functions of MgO layer have been investigated from their ion-induced secondary electron emission coefficient (${\gamma}$ ), respectively, using various ions with different ionization energies in a${\gamma}-FIB$ (Focused Ion Beam) system. We have compared work-function with${\gamma}-FIB$ system current signal for measurement defect energy level in MgO layer. MgO-A in the three types has lowest work-function value (4.12eV) and there are two defect energy levels. -
We have investigated the sputtering and secondary electron emission characteristics of MgO protective layer according to the
$O_2$ partial pressure. The MgO layer have been deposited by electron beam evaporation method and have varied the$O_2$ partial pressure as 0,$5.2{\times}10^{-5}$ ,$1.0{\times}10^{-4}$ , and$4.1{\times}10^{-4}$ Torr. It has been known that the secondary electron emission coefficient and the number of defect energy levels increased as the$O_2$ partial pressure increases. So we have investigated the property of sputtering yield according to the$O_2$ partial pressure. We have known that the sputtering yield deceases as the$O_2$ partial pressure increases by using the FIB system. -
This paper investigates how various concentrations of lithium ion influence on crystallization of MgO in thin films formed by spin coating and an the discharge characteristic in a flat fluorescent lamp structure. The XRD results indicate
$Li^+$ ion enhances the growth of MgO crystal in a spin coated thin film. The discharge property with the$Li^+$ ion doped MgO films show the lithium ion in MgO film clearly reduce the initial discharge voltages of test devices. Interestingly, the test panels with various doped MgO film have somewhat higher static memory margin of than that of pure-MgO owing probably to the pore structure of spin coated MgO films. The CL spectra, which confirm that the doping creates defects energy levels in the band gap of MgO, show the$F^+$ center is the main defects in doped MgO films. -
In this work, the discharge characteristics and temporal distribution of surface charges on the Sidoped MgO have been investigated and elucidated with the results of photon-induced surface current. Even though the Si doped MgO shows lower static voltage margin, higher luminous efficacy, and shorter statistical delay time, its discharge characteristics become deteriorated as the timing of scanning is delayed from the ramp type reset pulse down. Overall features of Si-doped MgO in discharge characteristics are well correlated with surface current characteristics.
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MgO thin films were deposited by e-beam evaporator using the 2-step method for alternate current plasma display panels (AC-PDPs). Glancing angle deposition (GLAD) method was employed to produce various surface geometry of the thin film; the bottom layer was deposited on a substrate by normal e-beam evaporation method and the top layer was deposited on bottom layer with
$85^{\circ}$ by GLAD method. Results show that firing and sustain voltages improved as the sharpness of surface and isolated columnar structures increases, respectively. -
Seo, Ji- Hoon;Kim, Jun-Ho;Seo, Ji-Hyun;Hyung, Gun-Woo;Lee, Kum-Hee;Kim, You-Hyun;Kim, Woo-Young;Yoon, Seung-Soo;Kim, Young-Kwan 1399
We have demonstrated efficient white WOLEDs by using three emissive materials for primary colors (red, green, and blue). The characteristics of WOLEDs showed the maximum luminance of$37600\;cd/m^2$ at 13V, the maximum luminous efficiency of 20.6 cd/A, and the$CIE_{xy}$ coordinates of (x = 0.33, y = 0.33) at 10V. -
Kim, Jun-Ho;Seo, Ji-Hoon;Seo, Ji-Hyun;Hyung, Gun-Woo;Lee, Kum-Hee;Yoon, Seoung-Soo;Kim, Young-Kwan 1403
An effective WOLED structure was demonstrated which improved a luminous efficiency and white color chromaticity independent on applied bias by employing effective carrier transporting layer, without any alteration of emissive materials. The modified WOLEDs exhibited 2 times higher luminous efficiency than the control device and showed balanced white emission during an operation. -
This work reports on three primary color fluorescent white organic light emitting diode (WOLED) with simple device structure where only a part of the hole transporting layer was doped with dye. The maximum luminance of the device reaches
$35000\;cd/m^2$ at a drive voltage below 11V and external quantum efficiency of the device is above 1% in the wide range of luminance from 10 to$35000\;cd/m^2$ and reaches its highest 1.6% at$500\;cd/m^2$ . The chromaticity coordinate shift of the device is negligible in this wide range of luminance. The blue shift of emission color with an increase of current density was attributed to the narrowing of recombination zone width with raise of current density. -
We have developed a top-emitting white organic electroluminescent device (TWOLED) incorporating a low-reflectivity molybdenum (Mo) anode and doped transport layers as well as a dual-layer architecture of doped blue and yellow emitters with the same blue host. The EL efficiency and operational lifetime of TWOLED can be enhanced by a factor of 1.2 and 3.4 than that of standard TWOLED, respectively, with a co-doping technology in yellow emitter by doping another blue dopant. The enhancement in device performances can be attributed to improve the energy transfer efficiency from blue host to yellow dopant through a blue dopant as medium in yellow emitter.
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Han, Seung-Jin;Kim, Jae-Hoon;Park, Yong-Sup;Back, Kyu-Ha;Kim, Gi-Heon;Hong, Sa-Hwan;Kim, Dal-Hyun;Kim, Jeong-Won 1415
Electronic and structural properties of the interfaces formed by pentacene deposited on a polymer-based dielectrics are investigated by electron spectroscopy, atomic force microscopy, and water contact angle measurement. There is strong influence of surface treatment of the polymer dielectrics on the energy level alignment and the surface topography upon the pentacene deposition. -
Color conversion technology using unique color conversion film for OLED back light was developed to achieve renovative performance for high- end display. It can reduce the production cost more than 20% due to cheaper cost for blue OLED and conversion film and also has a free chromaticity control capability for 10% raising color gamut with respect to LCD color filter. The OLED BLU by color conversion technology also shows excellent performances such as chromaticity stability. White efficiency using PLF + Blue OLED is 17cd/A@4.4V, CIExy(0.29, 0.31).
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A simulation method has been purposed in this paper to optimize the stack structure of metal/ITO cathode for full transparent or top emission devices. The result demonstrates that the complexity of the two proper layers thicknesses design is reduced. Finally, the experiment data also strain the simulation result.
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The amorphous IZO on flexible substrate (PC) shows similar electrical conductivity and optical transmittance with commercial ITO glass even though it was prepared at
$ < 50\;^{\circ}C$ . Moreover, it exhibits little resistance change during 5000 bending cycles, demonstrating good mechanical robustness. A green phosphorescent OLED fabricated on amorphous IZO on flexible PC shows maximum external quantum efficiency of${\eta}_{ext}=13.7\;%$ and power efficiency of${\eta}_p=32.7\;lm/W$ , which are higher than a device fabricated on a commercial ITO on glass (${\eta}_{ext}=12.4%$ and${\eta}_p=30.1\;lm/W$ ) and ITO on flexible PC (${\eta}_{ext}=8.5%$ and${\eta}_p=14.1\;lm/W$ ). -
Kim, You-Hyun;Choi, Jea-Yoon;Lee, Su-Hwan;Yoon, Hyun-Soo;Seo, Ji-Hoon;Park, Jung-Hyun;Kim, Young-Kwan;Kim, Woo-Young 1429
We fabricated white organic light emitting diodes(WOLED) having two complementary and three primary colors with emission layers of DPVBi / MADN : DCM2-0.5% and DPVBi /$Alq_3$ / MADN : DCM2-1.5%, respectively. WOLED using three primary colors shows broad electroluminescence including green emission peak at 510nm while optical properties of the two complementary WOLED was higher current efficiency of 6.2 cd/A than 4.9 cd/A of three primary color WOLED. The maximum luminescence of WOLED with two complimentary color was$15200cd/m^2$ along with luminous efficiency 6.2cd/A, as achieving stable white color coordinates for both of WOLEDs at (0.33 , 0.33) almost. -
Using a blue emitting DPVBi material and red dopant DCJTB, WOLEDs with and without green emitter C6 added in ETL or HTL have been fabricated. The chromaticity color index of WOLEDs without C6 depends strongly on the doping concentration. In addition, manipulating thickness of emitting layer is similar effect such as controlling weight concentration of dopant. While the white color of WOLEDs with C6 added in ETL or HTL depend on position of C6. WOLED of three colors added green dye have been shown turn-on voltage of 3.25V, and EL efficiency 3.05cd/A @9V,
$8102\;cd/m^2$ , CIE coordinates (0.30, 0.32). -
Lee, Young-Hoon;Kim, Jai-Kyeong;Yoo, Jai-Woong;Ju, Byeong-Kwon;Kwon, Jang-Hyuk;Jeon, Woo-Sik;Chin, Byung-Doo 1437
We fabricated white organic light emitting device (WOLED) with the layered fluorescent blue material and phosphorescent green/red dye-doped materials. Addition of the non-doped phosphorescent host material between the fluorescent and phosphorescent light emitting layers provided the result of broadband white spectrum, with improved balance, higher efficiency, and lower power consumption. In our devices, there was no need of exciton-blocking layer between the each emission layer for the further confinement of the diffusion of excitons. -
In this work, we have modeled and fabricated microcavity-enhanced OLED using the 1-dimensional distributed Bragg reflector model (DBR). Results show that simulated spectrum intensity of microcavity OLED increased more than 30% compared to the conventional OLED, by use of DBR with
$TiO_2$ and$SiO_2$ . Spectral change of green and blue emission was expected to give the deeper color. The experimental design and characterization as well as the matching with simulated properties were performed for microcavity OLED for actual application. -
The luminance and operating voltage were measured during OLED operation for the purpose of analyzing the efficiency and change of internal resistance. The half lifetime of OLED was affected by degradation of OLED due to heat generated by ambient temperature and self heating. The operating voltage constantly increased due to the increase of internal resistance. The half lifetime of OLED driven by constant current source was found to be longer than that of the OELD driven by constant voltage and the reasons were clearly explained in this paper.
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The electrical properties of organic lightemitting devices (OLEDs) with wide-bandgap impurity-doped emitting layers (EML) were investigated. While the luminous efficiency of OLEDs with a NPB or a DPVBi-doped
$Alq_3$ EML did not vary significantly with the current density, that of the OLEDs with a BCP-doped$Alq_3$ EML changed dramatically. -
The electrical and the optical properties of organic light-emitting devices (OLEDs) with or without multiple heterostructures acting as a hole transport layer were investigated. The efficiency enhancement mechanism in the OLEDs with multiple heterostructures is described on the basis of the electrical and the optical results.
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The electrical and the optical properties of blue organic light-emitting devices (OLEDs) with a multiple emitting layer (EML) acting as electron and hole trapping layers were investigated. While the luminance efficiency of the OLEDs with a multiple EML was very stable, regardless of variations in the applied voltage.
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To understand the electronic charge transfer from cathode to an ETL in the TEOLED, the pristine
$Alq_3$ thin film and the interfaces of both$Alq_3/Ba$ and$Alq_3/Au$ were investigated by using the NEXAFS spectroscopy. The unoccupied energy state of each interface using the NEXAFS Analyses at the C and OK-edges was assigned and charge transfer from Ba to${\pi}^{\ast}$ of$Alq_3$ was investigated in detail. -
In this study, we report the luminescent properties of white polymer light emitting diode (WPLED) fabricated by soluble methods with poly-fluorenebased polymers blends which emit blue and yellow light. A device structure of ITO/PEDOT:PSS/Emissive Layer (EML)/Al was employed.
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We demonstrate p-doped organic light emitting diodes (OLEDs) comprising tungsten oxide (
$WO_3$ ) and 1,4-bis[N-(1-naphthyl)-N'-phenylamino]-4,4' diamine (NPB). We propose the NPB :$WO_3$ composition functions as a p-doping layer which significantly improves hole injection that leads to the fabrication of 4-(dicyano-methylene)-2-methyl-6-(p-dimethylaminos tyryl)-4H-pyrane (DCMl) based p-doped OLEDs with high efficiency and long lifetime. -
We report on the effect of ambient gas on the OLED degradation. The operating voltage and quantum efficiency increases when the device is exposed to the atmospheric gas and then returns to the initial level of the device in vacuum when the atmospheric gas is evacuated. These changes in the OLED performance can be attributed to the ambient gas pressure.
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Seo, Ji-Hoon;Kim, Jun-Ho;Seo, Ji-Hyun;Hyung, Gun-Woo;Park, Jung-Hyun;Lee, Kum-Hee;Yoon, Seung-Soo;Kim, Young-Kwan 1470
We have demonstrated the optimization of white organic light-emitting diodes with two separated emissive layers using a blue fluorescent and a red phosphorescent dopant. The maximum luminous efficiency of the devices showed 7.93, 9.70, 11.8, and 14.3 cd/A. The$CIE_{xy}$ coordinates also showed (x = 0.33, y = 0.36), (x = 0.33, y = 0.35), (x =0.31, y = 0.35), and (x = 0.29, y = 0.36) at 6V, respectively. -
We demonstrate relaxation of roll-off characteristics by controlling the dopant concentrations and the thickness of an emitter layer in electrophosphorescence diodes composed of 2,6-dicarbazolo-1,5-pyridine (PYD2)-host doped with 25 wt%-Iridium(III)bis[(4,6-di-fluorophenyl)-pyridinato-
$N,C^2$ ] picolinate (FIrpic). -
This paper introduced a measurement method for image sticking based on human vision perception. Existing image sticking quantification method is mostly different from visible level by human perception. It takes a long time to measure image sticking which is degraded by time due to using a spot photometer, therefore many test samples could not be evaluated in a given short period of time in mass production line. However, the new measurement method in this paper is possible to evaluate a large quantity of samples in fast and high correlation with human perceptual level of image sticking.
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Kim, Young-Min;Choi, Hee-Jin;Cho, Seong-Woo;Kim, Yun-Hee;Kim, Joo-Hwan;Park, Gil-Bae;Lee, Byoung-Ho 1482
A three-dimensional (3D)-two-dimensional (2D) convertible display system using a plastic fiber array is proposed. The proposed system has an advantage of making use of a light source for 3D image from an arbitrary location. The optical efficiency of 3D images in the proposed system is enhanced compared with previous research. -
Generally many kind of phase unwrapping method are used to obtain three-dimensional feature in digital holography. Goldstein algorithm is representative method. But Goldstein algorithm has some problems. We developed a modified Goldstein algorithm that could solve the problem of Goldstein algorithm using the boundary information. Obtained three-dimensional information can be applied to 3-D contents of stereoscopic, multi-view, SMV, or holographic display.
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We proposed the method to take 3D image having correct depths to the front and rear directions when the stereogram was displayed to an observer through an optical system. Since the magnified stereogram by lenses was not given correct depth to an observer despite having the same magnified disparity. Consequently, we achieved our goal by relations of compensated disparities to both directions with magnification of lenses, viewing distance and base distance of viewer in AFIS.
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This paper deals with image quality analysis considering the impact of psychological factors involved in assessment. The attributes of image quality requirement were partitioned according to the visual perception characteristics and the preference of image quality were obtained by the factor analysis method. The features of image quality which support the subjective preference were identified, The adequacy of image is evidenced to be the top requirement issues to the display image quality improvement.
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Visual perception experiments were conducted to determine the acceptable limit of the contrast ratio of LCD TV under the watching condition. The results showed that the corresponding contrast ratio should be below 10,000:1 at the 3H(height of screen) distance in the living room environment.
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Auto-stereoscopic 3D of 60-view number is made using slanted lenticular lens array and LCD of 15.1 inch diagonal size and 3200 by 2400 pixel numbers. Due to its large view number, smooth motion parallax is observed and the visual fatigue is reduced.
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Depth data for is very important data for 3D display. Disparity and depth data makes users to feel 3D effect. We used stereo camera to measure depth and made fast algorithm to get in real time. This vision system can be substituted for expensive laser system.
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This paper introduces a new texture prediction for MVC( Multi-view Video Coding) which is currently being developed as an extension of the ITU-T Recommendation H.264 | ISO/IEC International Standard ISO/IEC 14496-10 AVC (Advanced Video Coding) [1]. The MVC's prcimary target is 3D video compression for 3D display system, thus, key technology compared to 2D video compression is reducing inter-view correlation. It is noticed, however, that the current JMVM [2] does not effectively eliminate inter-view correlation so that there is still a room to improve coding efficiency. The proposed method utilizes similarity of interview residual signal and can provide an additional coding gain. It is claimed that up to 0.2dB PSNR gain with 1.4% bit-rate saving is obtained for three multi-view test sequences.
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Long afterglow
$SrAl_2O_4:Eu^{2+}$ ,$Dy^{3+}$ is synthesized by a solid state reaction. The effect of flux$B_2O_3$ on the sintering dynamic process, the optimum concentrations of$Eu^{2+}$ and$Dy^{3+}$ for long lasting bright luminescence property and the effect of charge compensators like$Mg^{2+}$ ,$Zn^{2+}$ ,$Na^+$ ,$K^+$ on long persistence have been investigated. -
We demonstrate a high color gamut liquid crystal display (LCD) system (>100 %) by using a precompensated tri-chromatic LED-backlight module over a temperature range of (25 to
$70^{\circ}C$ ), whose pre-compensated optical characteristic balances the spectral redshift and intensity decrease due to the temperature rising during operation. -
In this work, a coplanar-type plasma flat fluorescent lamp having cross type of electrode was fabricated by screen printing and sealing technique. Cross type of electrode with a dielectric layer were screen-printed on a rear glass plate, and then fired at
$550^{\circ}C$ . Phosphor was printed on and fired at$450^{\circ}C$ . Finally, the lamp was sealed by frit glass at$450^{\circ}C$ . The lamp of cross electrode type was studied depending on the electrode gap and the thickness of dielectric layer. -
In this study, flat fluorescent lamps (FFLs) having surface discharge structures was fabricated by screen printing technique and were studied using spectraradiometer and square pulse power supply. Two types of FFLs having different shapes of electrodes (crosstype and line-type structure) were compared with variation of discharge shape and mixed gas ratio.
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Lee, Seung-Jae;Park, Joung-Kyu;Kim, Kyung-Nam;Bae, Pan-Kee;Kim, Chang-Hae;Chang, Hyun-Ju;Kim, Yong-Rok 1526
In this report, Manganese doped magnesium germanate ($Mg_4GeO_2:Mn$ ) phosphor has been synthesized by the solid state method. Also, this phosphor was prepared by simple process under an air atmosphere for oxidation of Mn. The prepared phosphor shows a main luminescent peak at 661nm. Therefore, this phosphor is possible to be applicable to white LED lamp by GaN or InGaN chips. -
The manganese co-doped
$Ca_8Mg_1(SiO_4)_4Cl_2:Eu^{2+}$ ,$Mn^{2+}$ phosphor was synthesized by solid-state reaction and its photoluminescence characteristics were investigated. The synthesized phosphor show two emission spetrums: green band of 512nm and yellow band of 550nm. White light-emitting diodes (LEDs) were fabricated through combination of a 405nm-emitting InGaN chip and a synthesis phosphor in a single package. Under 20mA current, its CIE chromaticity coordinates are x=0.40 and y=0.45 and a color temperature of 4053K. -
Kim, Ki-Seong;Jeon, Hyun-Woo;Hong, Jin-Woo;Yoon, Jung-Hyun;Kim, Jae-Bum;Jeong, Byoung-Koan;Shin, Jong-Keun;Chung, In-Jae 1531
We made a high-efficiency lamp with same spec. as a normal lamp by improving physical constants of a lamp and then analyzed varied effects. By applying novel physical constants to an EEFL, we acquired decrease of lamp operating power and voltage. -
Lee, Hak-Soo;Cho, Tai-Yeon;Gwak, Ji-Hye;Han, Sang-Do;Han, Chi-Hwan;Park, Sang-Hyun;Chun, Il-Su 1534
ZnS-based orange-emitting phosphors were synthesized by two-step firing process: above$1000^{\circ}C$ to obtain hexagonal phase, and at$750^{\circ}C$ for cubic phase. The effect of heat treatment condition on the optical properties was investigated to fine an optimum condition for high-performance ZnS:Mn,Cu,Cl phosphor. -
ZnS:Cu,Cl phosphor was synthesized by solid-liquid state reaction with two firing steps. Each stage of the process was carefully monitored so that the final product was comparable to commercially-available phosphor. The effect of
$Cu^{2+}-doping$ concentration has been investigated on the luminescence characteristics of ZnS:Cu,Cl blue-green phosphors for inorganic electroluminescent device. -
We have synthesized novel organic passivation materials to protect organic thin film transistors (OTFTs) from
$H_2O$ and$O_2$ using polyvinyl alcohol (PVA)/layered silicate (SWN) nano composite system. Up to 3 wt% of layered silicate to PVA, very homogeneous nanocomposite solution was prepared. -
Carbon nanotubes (CNTs) are coated on green
$ZnGa_2O_4:Mn^{2+}$ phosphor for filed emission display. The cathodoluminescent intensity of CNTs-phosphor is improved compared with uncoated phosphors. Also the effects of phosphors-coated CNTs on electrical and degradation characteristics are investigated to reveal the reason of the enhanced emission intensity. -
Zinc gallate-based RGB phosphors and vertically aligned carbon nanotube emitters are prepared for flat field-emission lamp. The blend phosphors of blue
$ZnGa_2O_4$ , green$ZnGa_2O_4:Mn^{2+}$ and red$ZnGa_2O_4:Cr^{3+}$ are coated on the front glass, and the carbon nanotubes are chemically bonded on the rear ITO glass as a cathode. -
$YVO_4:Eu^{3+}$ thin film phosphor samples have been deposited by using RF magnetron sputter deposition technique with various deposition temperatures. The Effect of deposition temperature (room temperature to$450\;^{\circ}C$ ) on morphological, crystal structure, and luminescence properties of$YVO_4:Eu^{3+}$ thin film phosphor has also been investigated. As the deposition temperature increases, the size of crystal grain and surface roughness of thin film increases principally and its crystallinity also increases. It is found that the asdeposited$YVO_4:Eu^{3+}$ thin film excited either photon or electron shows typical luminescence spectra successfully. CIE color coordinates of$YVO_4:Eu^{3+}$ thin film phosphor with increasing deposition temperature moved towards more reddish region. -
To overcome defect due to large surface of nanoparticle, a redispersible Eu doped
$LnPO_4:LnPO_4$ core/shell nanoparticles were prepared in a highboiling coordinating solvent. The particle size of the synthesized core/shell nanophosphors was estimated to be about 8 nm by TEM. In this core/shell nanoparticle, the concentration of Eu ion was optimized on the basis of the emission intensity under UV ray excitation. Also, the PL properties of the nanophosphors have been compared with those of the$LnPO_4:Eu$ nanoparticles. -
In study, we've disigned LGP that have optimized pattern for blue LED. We used to have active area 3.5" of LGP and blue led(6EA) of LUXPIA in Korea. Also, We made Pattern Generation.
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BGR mixture phosphor pumped by 400 nm is developed for white-light-emitting diode of liquid crystal display backlight. White-emitting phosphor is prepared by mixing
$Ba_2SiO_4:Eu^{2+}$ and$(Ba,Sr)_3MgSi_2O_8:Eu^{2+},Mn^{2+}$ phosphors. -
$Tb^{3+}-activated$ green-emitting$(Y,Gd)Ga_3(BO_3)_4$ phosphor has been investigated. The main absorption was in the$120{\sim}238$ nm and exhibited a green emission with the 545 nm and several peaks due to inner shell transition of$Tb^{3+}$ ion. With the optimized$Tb^{3+}$ concentrations, the maximum emission brightness was 90% of the$Zn_2SiO_4$ :Mn phosphor. -
A borate compound was adopted as new host material for
$Eu^{3+}$ ,$Tb^{3+}$ and$Tm^{3+}$ activators. The phosphor samples,$Gd_{1-x}Eu_xCa_3(GaO)_3(BO_3)_4$ ,$Gd_{1-x}Tb_xCa_3(GaO)_3(BO3)_4$ and$Gd_{1-x}Tm_xCa_3(GaO)_3(BO_3)_4$ have been synthesized by conventional solid-state reaction. The crystalline phase for the resulting powders was identified using an X-ray diffraction$system^1$ . Their photoluminescence properties under the excitation of UV ray were investigated. The Eu, Tb or Tm-doped$GdCa_3(GaO)_3(BO_3)_4$ emits efficient red, green or blue light, respectively. It was observed that the optimum concentration of Eu or Tb activator for the borate host was much higher than other$Eu^{3+}$ or$Tb^{3+}-doped$ phosphors. -
A two-dimensional fluid simulation code has been developed in order to investigate discharge phenomena and to improve plasma luminous efficiency in a Hg flat fluorescent lamp (FFL) for an LCD backlight unit. In this study, the method of a two-dimensional fluid simulation for FFL is explained and the simulation results of Hg-Ar-Ne mixture gas are presented for the enhancement of the luminance efficiency. The effects of various parameters, such as driving voltage, frequency, and gas mixture ratio, are investigated. The luminance efficiency increased with increasing fraction of mercury but the increasing fraction of argon did not affect the efficiency much.
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Lim, Seung-Han;Park, Jung-Hyun;Seo, Ji-Hoon;Ryu, Gweon-Young;Kim, Young-Kwan;Shin, Dong-Myung 1573
ABCV-Py, a new red fluorescent material, in which two identical electron donor (dimethylamino group) and acceptor (cyano group) moieties are linked to two independent biphenyl groups which share the same core phenyl, has been synthesized for use in OLED application. Performance of red doped electroluminescent devices using ABCV-Py as dopant were measured with various host materials,$Alq_3$ , CBP, DPVBi, and p-terphenyl. The performance of device with DPVBi host material was better than those with other host materials and high doping concentration could be applied on device with ABCV-Py as dopant. -
Xe content is one of important factors related to characteristics of the mercury-free flat fluorescent lamp. The electro-optical properties of lamp were investigated for wide range of Xe content in Xe-Ne mixing gas. The maximum luminance of
$9,289\;cd/m^2$ and efficacy of 3 lm/W was obtained with Xe 90 %. -
The composites were fabricated with titania used commercially and calcite as a filler in BZB glass matrix and their thermal, optical and electrical properties were investigated. From our results, calcite may be the profitable and highly efficient reflectance material as a filler for flat panel display devices.
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Huang, Chi-Yuan;Liu, Chia-I;Tsao, Keng-Yu;Kuo, Ju-Chien;Wu, Jing-Yi;Lo, Yu-Cheng;Liu, Pei-Yu;Wang, Jiun-Ming;Li, Huai-An 1583
The purpose of this research is to control proper processing condition of RGB photo resistant in the ink-jet process increasing processing ability by adding additives. The viscosities of modified RGB photo resistant were$10{\sim}14cps$ and the additives could decreased agglomeration and flowing trace of photo resistant effectively. Another way, the adhesion between photo resistant and glass substrate was improved by modifying photo resistant and substrate. The surface tensions of modified photo resistant were same as that of original RGB photo resistant. The additives appeared a better compatibility with photo resistant, and the micelle of photo resistant did not be broken during modified process. -
Jeong, Jong-Mun;Shin, Myeong-Ju;Kim, Jungh-Hyun;Lee, Mi-Ran;Jeong, Hee-Suk;Kim, Jin-Sheon;Hong, Byoung-Hee;Choi, Eun-Ha;Cho, Guang-Sup 1586
The influence of optical components constituting the backlight of TV on the luminance property of backlight was analyzed. The variation of luminance when the light emitted from light source passes each optical part was evaluated. -
In this study, we prepared CNF (carbon nanofiber) by the solvothermal method for FED (field emission display) applications. We controlled several conditions to synthesize effective CNF for field emission applications. Nano-sizesd Pt nanoparticles were coated on the CNF. In this study, we have applied Pt nanoparticles- coated CNF which can be produced in mass, to field emission application.
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Various yellow-emitting
$Y_3Al_5O_{12}:Ce^{3+}$ (YAG:Ce) nanocrystalline phosphors, where some$Al^{3+}$ sites are substituted with$Ga^{3+}$ or some Y sites with Gd3+, have been synthesized. The rare earth ions such as$Pr^{3+}$ and$Tb^{3+}$ were also co-doped into YAG:Ce system, leading to the tunability of CIE coordinates of emission. -
In TFT-LCD, mura is a defect which degrades the display quality. The resistance difference between gate lines is the main cause of H-Block mura. Two methods could eliminate this defect. A thinner gate layer or gate fan-out pattern decrease mura level. H-Block mura has been reduced after implementing the new schemes.
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TPS (Temperature Programmed Sublimation) technology is known to research for the plane evaporation of the organic film.[5] Using TPS technology, the plane source evaporation of NPB organic film has been studied for the first time. The NPB organic film consists of nano scale film phase and bulk phase on a substrate. The 400
${\AA}$ in film phase thickness of NPB sublimates at the$175^{\circ}$ of the Ta made metal plate. It was proved that the sublimation temperature of the organic film has much lower than that of the organic powder. ($130^{\circ}$ is lower for Alq3 and$90^{\circ}$ is lower for NPB.) -
The TPS (Temperature Programmed Sublimation) technology has been developed to monitor the plane evaporation of the organic films and introduced in SID2007, P53.[4] The Alq3 organic film is deposited on various metal surface such as Cu, Ti, Invar, STS to sublimate. The TPS signal confirms that the Alq3 film consists of nano scale film phase and bulk phase on all the metal plates. The sublimation temperature of the Alq3 film was much lower (
$130^{\circ}C$ ) than the vapor temperature ($265^{\circ}$ ) of the Alq3 powder. -
Kim, Ga-Eul;Kang, Mi-Jo;Lee, Min-Kyu;Jin, Dong-Jun;Jeong, Hee-Suk;Kim, Jin-Shon;Kim, Jung-Hyun;Koo, Je-Huan;Hong, Byoung-Hee;Kang, Juneg-Ill;Choi, Eun-Ha;Cho, Guang-Sup 1607
The measurement technology of the electrical and optical properties of CCFL and EEFL for LCD-BLU is investigated. The lamp current and voltage are affected by the leakage of parasitic capacitance. The methods using the photometer and the integrating sphere are compared to determine the lamp efficiency. -
Jung, Ki-Taek;An, Young-Ung;Ji, Jong-Yeoul;Choi, Jun-Young;Lee, Young-Jong;Han, Seung-Hoon;Jang, Jin 1611
This paper is concerned on design of organic flow deposition system and development of the deposition process for pentacene thin film by OFD and on electrical characteristics of pentacene films deposited by it. OFD will overcome vacuum thermal evaporator's limits and it will provide a large-scale mass, uniform and good electrical performance. -
Performances of LCDs are generally evaluated in terms of luminance and color versus viewing angle. In the present paper we show that this type of display can be favorably characterized in terms of polarization. We show that ELDIM EZContrast instrument can be used to measure the degree of polarization the light and the ellipticity and polarization direction of the polarized component. This measurement is made versus incidence angle between 0 and
$88{\circ}$ and for all the azimuth angles. Important differences between the displays can be detected and related to their internal structures when luminance and color profiles are quite similar. -
Novel optical measurement systems and improved cell configurations for measuring of azimuthal anchoring energies were developed. The difference between the mechanical rubbing direction and the optical easy axis that caused errors in the previous azimuthal anchoring energy measurement was compensated. In addition, the measurement accuracy of the twist angle and therefore the azimuthal anchoring energy was greatly enhanced. As a result, we were able to obtain valid azimuthal anchoring energy values for different alignment layers.
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In order to realize effective p-type doping in ZnO thin films, ZnO films were deposited on P-doped Silayers by RF-magnetron sputter deposition technique and annealed at various temperatures. The result indicated that ZnO film annealed at
$700^{\circ}C$ showed p-type conduction with a high carrier concentration in the order of$10^{19}\;cm^{-3}$ . -
Manivannan, S.;Ryu, Je-Hwang;Jeong, Il-Ok;Lee, Chang-Seok;Kim, Ki-Seo;Jang, Jin;Park, Kyu-Chang 1625
Dispersion of arc-discharged single-walled carbon nanotubes (SWNTs) has been accomplished by a water soluble polymer wrapping functionalization at room temperature. The treated SWNTs were redispersed in both aqueous and many organic solvents and the solutions were found to be stable. -
Significant process in the performance and commercialization of full-color thin-film electroluminescent(EL) displays has been achieved. This is due to the remarkable progress made in the performance of exiting EL phosphors, development of new phosphor materials, and design of new EL phosphor structures. In this paper, we fabricated thinfilm EL devices with ZnS buffer and
$BaTiO_3$ electric layer with on top and bottom of phosphor layer. The effect of ZnS and$BaTiO_3$ layer on the luminance of EL device were studied. -
Ryu, Je-Hwang;Kim, Ki-Seo;Lee, Chang-Seok;Min, Kyung-Woo;Song, Na-Young;Jeung, Il-Ok;Manivannan, S.;Moon, Jong-Hyun;Park, Kyu-Chang;Jang, Jin 1632
We developed a novel growth method of CNTs on metal substrate for device applications, deposited by a triode direct current plasma enhanced chemical vapor deposition (dc-PECVD). With resist-assisted patterning (RAP) method, we had grown CNTs on metal substrate, which were strongly bonded with metal substrate. -
We report on low-voltage pentacene TFTs with a Al2O3/OTS as a gate dielectric. Improving device characteristics, we performed chemical modification of self-grown Al2O3 surface with an octadecyltrichlorosilane(OTS) self-assembled monolayer(SAM). As the result of this combination, the mobility was improved from 0.3 to
$0.45\;cm^2/Vs$ . In addition, we examined that the SAM dipole electric field have an influence on gate leakage current, transfer and output characteristics. -
Cho, Seon-Ah;Lyu, Jae-Jin;Sohn, Ji-Won;Park, Jin-Won;Park, Seung-Beom;Yang, Sung-Hoon;Jung, Mee-Hye;Kim, Kyeong-hyeon;Kim, Sang-Soo 1639
We have designed cost competitive pixel structures for high performance mobile PVA LCDs. These new structures significantly bring down the price by the use of a conventional polarizer for lowest possible cost. A 4.3" prototype based on these techniques was built, achieving the world's highest mobile display contrast ratio of 1200:1, while maintaining wide viewing angle with no loss of transmittance -
The brightness of LED changes according to the current flowing through LEDs. The current mirror was used to drive LEDs effectively. The reference current of the current mirror was usually controlled by the resistor but the size of this resistor is very large and this resistor consumes too much power for high power LED backlight driving. The reference current of the current mirror LED driver was controlled by using flyback converter at small size with low power consumption in this paper. The concept of active current source was presented.
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RF plasma and aerosol nano process were developedfor a volume production of nanoscale phosphors. R, G, and B PDP phosphors were synthesized and the characteristics were optimized through the proprietary power treatments. PL intensities were confirmed to be enhanced up to 70% of that of present commercial phosphors.
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We demonstrate fluorescent green organic lightemitting diodes employing a rhenium oxide (
$ReO_3$ )-doped N,N-diphenyl-N,N'-bis(1,1'-biphenyl)-4,4'-diamine (NPB) hole transporting layer (HTL). The devices exhibit significantly reduced driving voltages as well as prolonged lifetime. Details of$ReO_3$ doping effects are described in terms of charge transfer complex and stabilization of HTL morphology. -
Kang, Jae-Wook;Lee, Se-Hyung;Park, Hyung-Dol;Jeong, Won-Ik;Yoo, Kyung-Mo;Park, Young-Seo;Kim, Jang-Joo 1654
We demonstrate that the reduction of quantum efficiency with increasing current density in phosphorescent light emitting diodes (PhOLEDs) is related to the formation of excitons in hole transporting layer based on the analysis of emission spectra and exciton formation zone. By employing dual emitting layerm we could achieve maintaining quantum efficiency at high current density up to$10000\;cd/m^2$ as 13.1% compared to the devices with single emitting layer (S-EML) (${\eta}_{ext}$ = 6.9% at$10000\;cd/m^2$ ). -
Lee, Sung-Soo;Choi, Jun-Ho;Ha, Jae-Kook;Lee, Sang-Pil;Kim, Seong-Min;Choi, Ji-Hye;Lee, Soo-Yeon;Kim, Hyo-Seok;Chu, Chang-Woong;Shin, Sung-Tae;Kim, Chi-Woo 1658
We fabricate green device having unique life time characteristics of operating voltage reduction with time,${\Delta}V_{op}$ <0. A green device needs lower voltage than initial voltage for sustaining constant current as life time goes on. It means there are two possible reasons; one is interface modification between anode and HIL due to oxygen plasma treatment and the other is bulk property modification due to combination of new green host and new green dopant. From these materials and oxygen plasma treatment, we can make white OLED device having the characteristics of low${\Delta}V_{op}$ increasing. -
Chong, Jong-Ho;Lee, Seung-Bae;Lee, Sang-Myung;Choi, Young-Chul;Bae, Jae-Woo;Kim, Hun-Soo;Chung, Ho-Kyoon 1661
The contrast of display is one of the important specifications. Even if the contrast indicates luminance range which is a capability of the display and is greater in lower luminance or higher luminance, we consider that the greater contrast gets not the better performance. It is not the same value in human visual system. In practice, it is difficult to achieve the full dynamic range seen by human beings using electronic equipment. Therefore, we consider ambient condition and human perception to calculate perceptual contrast using the CIECAM02. In this paper, we propose perceptual contrast that is calculated using the brightness of CIECAM02. -
The belt source evaporation is for the large size AMOLED devices to re-sublimate the organic film deposited on the metal plate. Using the plane source, the PL spectrum of the doped organic film has been studied for the first time. The PL peak of the pure Alq3 film was 512nm and that of the pure Rubrene was 557nm. The PL peak of the 2% Rubrene doped Alq3 film was shifted to
$536{\pm}2nm$ . The PL peak wavelength measured at the front surface of the film and at the back surface of the film was measured as nearly same as that the doping ratio maintains uniform within the film thickness. In conclusion, the doping control of the organic film becomes real using the belt type plate sublimation deposition. -
We have investigated the degradation mechanism of hydrogenated amorphous silicon (a- Si:H) thin film transistors (TFTs) The threshold voltage of driving a-Si:H TFT is shifted severely by electrical bias due to a charge trapping and defect state creation. And the short channel TFTs exhibit less threshold voltage degradation than long channel TFTs. We propose the pixel circuits employing negative bias annealing scheme in order to suppression of threshold voltage shift of a-Si:H TFT.
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Thickness dependent morphology of ZnO films was studied, and ZnO can be intentionally grown into amorphous phase by reducing the thickness. The top-gate amorphous ZnO TTFTs with rather high field-effect mobilities and on/off current ratios were effectively fabricated.
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The integrated circuits such as inverters, ring oscillators, NAND and NOR gates, and rectifiers were fabricated on PEN substrate by using pentacene TFTs. The OTFTs used bottom contact structure and produced the average mobility of
$0.26\;cm^2/V.sec$ and on/off current ratio of$10^5$ . All circuits worked successfully like the simulation results. Especially, the rectifier was able to operate up to 1 MHz input signals, and ring oscillator exhibited oscillation frequency of 1MHz at-40V. -
Excellent moving picture performance of plasma TV has been confirmed through the study and measurement using the method proposed by the APDC (Advanced PDP Development Center Corporation). Full-HD Plasma TVs with pixels of
$1920{\times}1080[1]-[2]$ , showed more than 900 TV-lines of resolution out of maximum scale of 1080, while typical LCD of the same pixel count showed only 1/3 of the plasma's performance. Moreover, even the latest 120Hz models of$1920{\times}1080$ LCD do not much PDPs with pixels of$1024{\times}768$ , or$1366{\times}786$ in moving picture resolution. The measurement system proposed by the APDC showed very good agreement with subjective tests. -
This paper shows that the boundary image sticking can be prohibited completely by using the vacuum sealing process, which means that the residual impurities such as nitrogen or oxygen can be a critical factor inducing the boundary image sticking. The production of boundary image sticking was checked in the test panel fabricated by the
$N_2$ or$O_2$ flow during the vacuum sealing process. As a result, the boundary image sticking did not appear in the case of$N_2flow$ , whereas the boundary image sticking was observed in the case of$O_2$ flow even though the test panel was fabricated by the vacuum sealing process. -
We describe the image enhancement method of applying two spatial filters with different characteristics adaptively. An adaptive method is introduced so that sharpness enhancement is performed only in regions where the image exhibits significant dynamics, while noise reduction is achieved in smooth regions. Simulation results show that the proposed method improved the image quality.
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We will discuss encapsulation of OLEDs on both flexible and rigid glass substrates. Accelerated testing at 6CC/90RH and 85C/85RH is compared and acceleration factors for OLED and Calcium test samples are discussed.We have tested the stability and performance of our barrier coating to much higher temperatures: up to 140 C. Water Vapor Transmission rates at temperatures from 60 to 140 C are presented. Rates and methods for low cost manufacturing on a large scale are analysed
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Hsieh, Huai-En;Huang, Bohr-Ran;Juang, Fuh-Shyang;Tsai, Yu-Sheng;Chang, Ming-Hua;Liu, Mark.O.;Su, Jou-yeh 1703
Before the ultra-violet glue encapsulation, the research evaporated LiF thin film on device surface to be the extra packaging layer for improving the lifetime of organic light-emitting diode. The formula of UV glue was specially developed. We found 100 nm LiF is the optimum thickness. The best lifetime obtained by using LiF and special UV glue is 2.4 times longer than those by commercial UV glue. -
A possibility of work function engineering on ZnO thin film is studied by in-situ and ex-situ doping process. The work function of ZnO thin film decreases with increasing boron and phosphorus doping quantity. But, the work function of Al-doped ZnO (AZO) thin film increases as the boron doping quantity incresess. The range of work function change on ZnO thin films is 3.5 eV to 5.5 eV. This result shows that the work function of ZnO thin film is indeed engineerable by changing materials of dopants and their compositional distribution of surface. We also discuss the possible mechanism of work function engineering on ZnO thin films.
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Various manufacturing methods are analyzed by using manufacturing metrics to validate which method would be applicable to flexible microelectronics. Among others, Roll-to-Roll method is revealed to inherently have an excessive WIP resulting in long cycle time and limited diversity as well as low equipment efficiency.
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Jang, Jin-Nyoung;Oh, Kyoung-Suk;Yoo, Suk-Jae;Kim, Dae-Chul;Lee, Bon-Ju;Yang, Ie-Hong;Moon, Ji-Sun;Kim, Jong-Sik;Choi, Soung-Woong;Park, Young-Chun;Hong, Mun-Pyo 1715
New ITO thin film of good performance has been developed by brand-new, plasma-damage-free sputtering process at the room temperature. The room temperature-processed ITO films with optimized conditions as neutral beam acceleration bias of -30V and In & Sn composition ratio of 99:01 gives lower resistivity as$4.22{\times}10^{-4}{\Omega}-cm$ and higher transmittance over 90% a wavelength of 550 nm. The transmission electron microscope (TEM) images of the films show a nano-crystalline structure. -
Major display equipment suppliers have introduced equipment using ink jets for manufacturing steps such as printing the polyimide alignment layer and printing color filters. This paper will discuss the status of ink jets as precision deposition tools and the new technology being introduced for ink jet manufacturing.
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We will discuss and compare the different ways to manufacture high performance Barix coated barrier films as a substrate for displays: R2R vs Batch. It will be shown that the barrier performance of the Barix coating on plastic can be as good as on glass substrates. More then 1000 hrs of testing at 60C/90RH can be passed without degradation of Ca samples
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We introduce a mobile-type 3D display that achieves a full directional motion parallax and the real time interactions between the observer and the 3D image at the same time. These effects can be unique specified to the mobile-type 3D display.
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Integral floating is three-dimensional display technique which is a combination of integral imaging and floating display. In this paper, we explain and analyze the relation between the special viewing characteristics and the system factors of integral floating system. The experimental results which prove the analysis will be presented.
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An intelligent remote controller for 3-D TV interface exploits an artificial system of human visual attention for an easy interaction.
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A 3D projection display using stacked screens to display the near and far images, respectively, is developed. The front screen is made of a scattering polarizer film, and the far image on the rear screen is clearly visible through it. The image is perceived as three-dimensional, and no eyestrain is suffered.
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First, thin-film photodevices are evaluated, and a p/i/n thin-film phototransistor (TFPT) is recommended because the photo-induced current is relatively high and independent of the applied voltage. Next, an artificial retina is developed using the p/i/n TFPTs, and it is found that it can detect photo illuminance profile with sensitivity control.
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The Near to Eye Display (NED) solves the problem of having a display larger than a small portable device. The virtual image of the NED is created using a microdisplay and imaging optics. It is important that the optics does not interfere with the human visual system and that the device is light, compact and easy to wear. In this paper the principles of a biocular NED, which is based on a novel diffractive Exit Pupil Expander (EPE), are presented. The optical system is compact and intrinsically free from distortions and misalignments.
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In the field of 3D display, holographic displays are the only technology allowing optimal user comfort. We have developed systems based on compact projection optics, that allow advantageous new features, like large size full-color3D scenes generated at high rate on a micro-display with state of the art resolution.
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Moving a droplet by electrowetting is the basis of our novel displays. This enables mechanical bistable and high reflective monochrome as well as color systems. Since no high temperature process is required, plastic substrates can be used. Our prototypes show promising performance in terms of a wide temperature range, contrast ratio and color.
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Three technical obstacles must be overcome to build a fruitful business in the nascent industry of flexible microelectronics: the self-heating effect of thin film transistors (TFTs), the thermal and mechanical durability of flexible devices, and the cost issue. The self-heating effect is controlled through TFT shape, TFT electrical performance, dimensional reduction and energy-efficient circuits. Plastic engineering is one of the keys to solving thermal and mechanical durability problems faced by flexible microelectronics devices. For the Suftla flexible microelectronics business to be viable, Suftla transfer yield must be sufficiently high to keep down device cost. Improving the transfer yield is not easy, but it is the same challenge already faced and cleared in the TFT liquid crystal display industry.
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The key development issues in the flexible displays are TFT backplane technology for their various applications, which requires competitive device performance as well as its low temperature process. In this paper, with shortly reviewing recent flexible display development status, we describe technical trends of low-temperature a-Si TFTs. Our TFTs show good device characteristics enough to apply LCD and electrophoretic display.
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Surface modification of the gate dielectric has a strong influence on the performance of printed transistors. The surface modification occurs between the gate dielectric and semiconductor. The printed transistor with evaporated vanadium pentoxide (
$V_2O_5$ ) modification exhibits a mobility of$0.2cm^2\;V^{-1}\;s{-1}$ and a subthreshold slope of 1.47 V/decade. -
Kim, Jae-Hyun;Lee, Bo-Hyun;Moon, Tae-Tyoung;Park, Mi-Kyung;Chae, Gee-Sung;Kang, In-Byeong;Chung, In-Jae 1774
Ultra-fine Ag line was automatically patterned to the extent of 10${\mu}m$ in width by slit coating on the$10^4$ $mm^2$ glass, which was pre-patterned as hydrophobic and hydrophilic zone by using hydrophobic material. The resistivity of Ag film was about$4{\mu}\;{\Omega}{\cdot}cm$ . -
The increase of repetition rate, the dithering of laser optics, and the extension of pulse duration time are major approaches in improving the picture quality of AMOLEDs fabricated by excimer laser crystallization (ELC). Advanced solid phase crystallization (ASPC) has been developed to improve the uniformity and the process cost. Even though the mobility of ASPC-TFT is lower than that of ELC-TFT, it is high enough to drive AMOLED pixels.
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We investigated the effect on light extraction in OLED by introducing aluminum micro bump light scattering reflector. By attaching the micro bump reflector to a both side emission OLED, we found that the light extraction was 1.7 times larger than a simple flat reflector. We fabricated a 20.8” inch WXGA full color AM-OLED by integrating the micro bump scattering reflector.
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We fabricated OTFT-OLED display panel by using Ag-paste for source and drains electrode of OTFTs. The OTFTs were fabricated by solution processes such as spin-coating for PVP gate dielectric and screen printing for S/D electrodes with Ag-paste, except pentacene active layer which was deposited by evaporation. The mobility was 0.024 cm2/V.sec , off state current
${\sim}10-11A$ , threshold voltage 7.6 V and on/off current ratio${\sim}105$ . The panel consisted of 16 x 16 pixels and each pixel consisted of 2 OTFTs, 1 Capacitor and 1 OLED. The pixels successfully worked in terms of current magnitude supplied to OLED and the control ability of driving and switching OTFTs. -
We have proposed a new driving method which improve the current stability of a-Si:H TFTs for AMOLED. It performs the negative bias annealing on driving TFTs during a certain period of a frame time. In the proposed method, the range of data signals is significantly reduced by modulating VSS.
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In the constructed auto-stereoscopic display system for one observer. 1.stereoscopic images displayed on a special LCD are made on a large concave mirror. 2.The view-zone limiting aperture is set between the projection lens and the concave mirror. 3.The real image of the aperture is made at the observer's eye position by the concave mirror. 4.The observer's eye-position tracking of the view-zone is realized. 5.At same time, stereoscopic image changes automatically according to the eye position of the observer.
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We have developed a 2D/3D time sequential LCD autostereoscopic display, which is capable of simultaneous displaying 2D and 3D graphics at a frame rate up to 120 Hz. Left and right sets of viewing zones are formed by a combination of a fast LC shutter and a lenticular lens array.
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The evolution of a multi viewer autostereoscopic display is described. Development of the display was originally a part of the EC funded 'ATTEST' project and continues as another EC project 'MUTED'. The design of the original display is presented and the limitations of the prototype are described. The current iteration of the design is presented.
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Accommodation error is one of the main factors that degrade the comfort while watching stereoscopic 3D images. We analyze the limit of the expressible 3D depth without an accommodation error using the human factor information and wave optical calculation under Fresnel approximation.