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International Conference on (ICEPT) Electronic Packaging Technology

作者： Tian-yi Geng Jing-yu Fan Yan Zhang Shun Wang Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai China Key Laboratory of Advanced Display and System Applications Shanghai University Shanghai China

The present paper paid particular attention to the flow and heat transfer performance for an array of micro jets impinging upon the dimpled surface by means of CFD modeling. The modeling of a three-by-four jet array impinging upon the smooth, concave- and convex-dimpled surfaces was carried out based on the solution of the steady, incompressible and three-dimensional RANS and energy equations by employing the RNG k-epsiv turbulence model. It has been demonstrated from the present study that the heat transfer performance for an array of the micro jets impinging onto the concave- or convex-dimpled surfaces tends to be somewhat attenuated or augmented in the impingement region, respectively, as compared with that onto the smooth one. And the variational trend with respect to the Nusselt number distribution in the inter-jet region appears to be inconsistent with that in the impingement region. In addition, the flow pattern and primary mechanism by which the smooth, concave- and convex-dimpled surfaces significantly affect the flow field and heat transfer are analyzed and discussed.

关键词： Heat transfer Heat sinks Rough surfaces Surface roughness Microstructure Microchannel Temperature Thermal stresses Electronics cooling Geometry

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Global motion estimation for moving object extraction in MPEG video streams

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Journal of Information and Computational Science 2009年第1期6卷 341-350页

作者： Yang, Gaobo Zhou, Qiya Zhang, Zhaoyang College of Computer and Communication Hunan University Changsha 410082 China Key Lab. of Advanced Display and System Applications Shanghai University Shanghai 200072 China

In this paper, a novel moving object extraction scheme for MPEG video stream is proposed. Firstly, the DC and AC [1], AC [8] coefficients are extracted directly from MPEG video stream to re-construct the DC + 2AC image, which is used to obtain the contour feature of I frame. Secondly, the sparse motion vector field of P frame is interpolated to make it dense and then projected to I frame iteratively. Moving object is extracted by the fusion of spatio-temporal segmentation. The innovation lies in the global motion estimation (GME) algorithm in compressed domain to compensate the global motion caused by camera. Thus, the proposed approach is feasible for almost any sequence including the static scene and the dynamic scene. Since only the background blocks are used to estimate the motion parameters, the computational complexity is greatly reduced. Experimental results demonstrate that the proposed approach can obtain satisfactory segmentation results and can be used in real-time system because it is mainly implemented in the compressed domain. © 2009 Binary Information Press.

关键词： Real time systems

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Efficient energy transfer of red organic light emitting devices using two species of donors in emissive layer

Efficient energy transfer of red organic light emitting devi...

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16th International display Workshops, IDW '09

作者： Lu, Lin Zhang, Jianhua Wei, Bin Zhang, Hao Xu, Hongguang Key Laboratory of Advanced Display and System Application Ministry of Education Shanghai University 149 Yanchang Rd Shanghai 200072 China SVA Electron Co. Ltd. FPD Building 149 Yanchang Rd Shanghai 200072 China

We investigated the characteristics of red OLEDs with two donors and one dopant. The EL efficiency of novel device increased two folds compared to devices with single host materials while the peak emission kept unchan... 详细信息

关键词： Light emission

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Study on moisture behavior in flip chip BGA packages and bake process optimization

Study on moisture behavior in flip chip BGA packages and bak...

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International Conference on (ICEPT) Electronic Packaging Technology

作者： W.Q. Dai Z.K. Hua J.H. Dai E.W. Pang L. Jiang C.Y. Li P. Liao J.H. Zhang Intel Products (Shanghai) Company Limited China Key Laboratory of Advanced Display and System Applications Ministry of Education School of Mechanical & Electronic Engineering and Automation Shanghai University Shanghai China

The lead-free (LF) and halogen-free (HF) ldquogreenrdquo initiatives are driving the advanced packaging manufacturers to develop new generation materials and assembly technologies. However, the moisture related reliability issues become the significant technical challenge to meet stringent reliability and quality standards comparing to the previous Lead and halogen technology. In this study, the moisture absorption and desorption performance of halogen free and lead free material were investigated. The experimental data revealed that after fully baked process there was still some resident moisture which was mainly contained at substrate level. The modeling data of moisture absorption and desorption behavior with 125degC bake comparison was discussed and was fully aligned with experimental data. Moreover, a dasiasoft bakepsila method via Nitrogen and dry air was introduced. In low RH effect test, under 25degC / 60%RH precondition process, all the moisture absorbed for 1100 hours can be removed by dasiasoftpsila bake. This indicates that not only no moisture absorption in low RH environment, but also an additional dasiasoft bakepsila process occurring during the storage time. The results demonstrated that the storage of moisture-sensitive material in the optimized environment is an attractive facility solution which can reduce the risk of popcorn and cracking problems.

关键词： Moisture Flip chip Packaging Environmentally friendly manufacturing techniques Absorption Material storage Hafnium Assembly Nitrogen Testing

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Efficient and chromatic-controllable white organic light-emitting diodes on plastic substrates using color conversion methods

Efficient and chromatic-controllable white organic light-emi...

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16th International display Workshops, IDW '09

作者： Li, Bo Sun, Sanchun Lu, Lin Liao, Yingjie Li, Chunya Zhang, Jianhua Xu, Hongguang Wei, Bin Key Laboratory of Advanced Display and System Application Ministry of Education Shanghai University 149 Yanchang Rd. Shanghai 200072 China SVA Electron Co. Ltd. FPD Building 149 Yanchang Rd. Shanghai 200072 China

The chromatic-stability white organic light emitting diodes have been investigated basing on color conversion method, and result found little CIE coordinate migration under driving voltage from 5V to 12V.

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Study on the degradation of sealed organic light-emitting diodes under constant current

Study on the degradation of sealed organic light-emitting di...

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International Conference on (ICEPT) Electronic Packaging Technology

作者： Xiao-Ming Xu Wen-Qing Zhu Qiang Wang Zhi-Lin Zhang Xue-Yin Jiang School of Material Science and Engineering Key Laboratory of Advanced Display and System Application Ministry of Education Shanghai University Shanghai China

Degradation characteristics of sealed OLED devices under four different constant currents were investigated by using OLEDs aging tester. We found that the higher the applied current density was, the faster luminance decayed. There was a relationship between luminance and lifetime when the current density was within 200 mA/cm 2 . In addition, spectrum characterization indicated that the peak wavelength didn't shift during the aging process, which implied that the carriers recombination occurred near the NPB/Alq 3 interface all along even when OLEDs luminance dropped down to half of the initial value, indicating that the degradation wouldn't lead to the deviation of the carriers recombination region. Through the metallurgical microscopy observation, the number of bubbles and dark spots were noticed to increase continuously and the non-emissive area kept growing around the bubbles. It showed that bubbles would badly accelerate the formation of dark spots. By investigating luminance degradation under constant current, we draw a conclusion that OLEDs luminance degradation is not entirely coulombic. After introducing an acceleration coefficient, the formular could be applicable until the current went beyond some degree.

关键词： Thermal degradation Organic light emitting diodes Glass Aging Cathodes Indium tin oxide Flat panel displays Current density Acceleration Anodes

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Modeling of nanostructured polymer-metal composite for thermal interface material applications

Modeling of nanostructured polymer-metal composite for therm...

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International Conference on (ICEPT) Electronic Packaging Technology

作者： Zhili Hu Bjorn Carlberg Cong Yue Xingming Guo Johan Liu SMIT Center and BioNano Systems Laboratory Department of Microtechnology and Nanoscience Chalmers University of Technology Goteborg Sweden Key Laboratory of Advanced Display and System Applications Ministry of Education and SMIT Center School of Mechatronics Engineering and Automation Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai China Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai China Key Laboratory of Advanced Display and System Applications Ministry of Education and SMIT Center School of Mechatronics Engineering and Automation Shanghai University Shanghai China

Previous studies have discovered a unique type of nanostructured polymer-metal composite for thermal interface material with effective thermal conductivity of 8 W/mK. It is a promising result but extensive efforts are still required to further enhance the thermal conductivity. Therefore, this paper will try to help the process with modeling and simulation. Calculations reveal the alignment of the fibers have insignificant influence. Therefore volume percentages of fiber together with mean interface temperature become the dominating parameters of effective thermal conductivities of thermal interface material. Based on this approximation, simulation was taken which showed good results in comparison with experimental data. However, the preferred volume percentage of fibers (33%) was slightly too large according to the surface image of thermal interface material.

关键词： Polymers Composite materials Nanostructured materials Thermal conductivity Electronic packaging thermal management Conducting materials Thermal resistance Thermal management Polyimides Thermal management of electronics

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Effects of the matrix shrinkage and filler hardness on the thermal conductivity of TCA

Effects of the matrix shrinkage and filler hardness on the t...

引用

International Conference on (ICEPT) Electronic Packaging Technology

作者： Cong Yue Yan Zhang Zhili Hu Johan Liu Zhaonian Cheng Key Laboratory of Advanced Display and System Applications Ministry of Education SMIT Center School of Mechatronics Engineering and Automation Shanghai University Shanghai China SMIT Center & Bionano Systems Laboratory Department of Microtechnology and Nanoscience Chalmers University of Technology Gothenburg Sweden

Thermal conductive adhesives (TCA) have been widely used as the thermal interface material (TIM). The TCA are usually epoxy or silicone based mixtures containing fillers. The epoxy in TCA also applies a pressure on the filler particles as it shrinks during the curing process. This pressure leads to an increase in the contact area between the filler particles and thus improves the thermal conductivity. In our attempt to discover the effect of filler modulus on the contact areas between two particles we constructed a cell model assay. In order to study the different epoxy characteristics, 28 cases were simulated with different mixtures of epoxy and filler. The thermal conductivity of each case was calculated by FEM. When the shrinkage was higher than 1%, TCA with a filler modulus of 83 Gpa (silver) has the largest contact area, which suggests silver has the best TCA performance among the studied materials. Furthermore the viscoelasticity of the epoxy was simulated to evaluate the fully relax time of epoxy and the effect on the thermal conductivity of TCA.

关键词： Thermal conductivity Silver Conductive adhesives Conducting materials Curing Phase change materials Thermal engineering Heat transfer Electrons Temperature

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Interactive object segmentation using kernel density estimation based graph cuts

Interactive object segmentation using kernel density estimat...

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International Conference on Wireless Communications and Signal Processing (WCSP)

作者： Zhongmin Han Baoyan Ding Zhi Liu Liquan Shen Zhaoyang Zhang School of Communication and Information Engineering Shanghai University Shanghai China Key Laboratory of Advanced Display and System Application Ministry of Education Shanghai China

This paper proposes an efficient and flexible interactive object segmentation approach using kernel density estimation based graph cuts. First, the user draws scribbles to roughly mark the interested object and background, respectively, and the likelihood of object versus background is evaluated for each pixel using nonparametric kernel density estimation. Then pixels are globally classified into object and background using graph cuts, which uses likelihood as data cost and gradient information to generate a spatial varying smoothness cost. If the user is not satisfied with the initially segmented object, the user is allowed to mark these undesirable regions by drawing additional scribbles. A local region for refinement is then adaptively determined, and pixel reclassification is performed to extract a more accurate object boundary. Experimental results on a variety of images demonstrate that interested objects with good visual quality can be extracted with less user interaction and a timely response.

关键词： Object segmentation Kernel Image segmentation Humans Iterative algorithms Data mining displays Pixel Cost function Parametric statistics

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Color correction method based on histogram segmentation for multiview video

Color correction method based on histogram segmentation for ...

引用

IET International Communication Conference on Wireless Mobile and Computing (CCWMC 2009)

作者： Yi Liu Yongfang Wang Zhaoyang Zhang School of Communication and Information Engineering Shanghai University Shanghai China Key Laboratory of Advanced Display and System Application Ministry of Education Shanghai China

Color differences between different views can cause performance degradation in multiview video coding. In order to overcome this problem, in this paper a local color correction method based on histogram segmentation is proposed. In the proposed method, we correct the color changes in the different segmentation regions between the current picture and the reference picture. Extensive experimental results demonstrate that the proposed method outperforms the traditional global linear color correction methods with objective mean of disparity values and subjective visual quality, and achieves better correction results.

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