最新刊期
期 2 ， 2011
- 摘要：The first series of polyimides with different ratio of side chain were copolymerized from 4-octyloxy-biphenyl-3,5-diaminobenzoate(C8),3,3'-dimethyl -4,4'-methyl-enedianiline (DMMDA) and 4,4-oxydiphthalic(ODPA) via one-step method.The effect of the diamine content of these PIs on their solubility,alignment,pretilt angle and thermal stability was investigated. Similarly,the second series of polyimides with different main chain were copolymerized from C8,DMMDA and different dianhydrides which include ODPA,pyromellitic dianhydride (PMDA),3,3',4,4'-dibenzophenonetetracarboxylic dianhydride (BTDA) via one-step method. The effect of dianhydride structure on the solubility and thermal stability was explored.关键词：polyimides;solubility;alignment;pretilt angle;thermal stability
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发布时间：2020-08-12 -
Effect of Grooved Surface with Arbitrary Shape on Anchoring Energy of Biaxial Nematic Liquid Crystal
摘要：Under the approximation of Berreman, any grooved surface with arbitrary shape can be described in terms of Fourier series. Based on the theory of Fukuda et al, the expression of anchoring energy with an additional term was obtained, taking into the surfacelike elastic term in biaxial nematic liquid crystal. The figures of reduced anchoring energies versus the angle between the direction of the grooves and main director were simulated under the different values of surfacelike elastic constant in certain cases and the effect of biaxial elastic constant on easy axes was discussed.关键词：biaxial nematic liquid crystal;groove;Fourier series;anchoring energy- 14
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发布时间：2020-08-12 - 摘要：By employing cesium carbonate doped tris-(8-hydroxyquinoline) aluminum/MoO3 as the effective charge generation layer (CGL), high efficiency two-unit series connected tandem organic light-emitting diodes were fabricated. It is found the performance of the two-unit tandem devices can be controlled by the thickness of the MoO3 layer. The 30 nm-thick MoO3 CGL tandem device exhibits the best device performance with the current efficiency of 14.5 cd/A, which is above 2.0 times than that of the control device over a wide range of current densities. Its suggested that the connecting layer broke down under a high current density, leading to the decrease of current efficiency. The improvement of tandem device performance is attributed to the efficient electron and hole injection from charge generation layer to two adjacent emission units.关键词：OLEDs;charge generation layer;tandem;MoO3;Cs2CO3
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发布时间：2020-08-12 - 摘要：This paper focuses on the comparison and analysis of ZnO TFTs and IGZO TFTs optical and electrical performance, and the stability of threshold voltage. The comparison results indicate that both ZnO and IGZO thin film materials have a simply high optical transmittance in the range of visible spectrum. Furthermore,the key electrical properties of IGZO TFT are better than that of ZnO TFT under the same deposition condition, such as the field effect mobility, the on/off ratio, the threshold voltage and the subthreshold slope. The leakage current of both ZnO TFT and IGZO TFT is low, and the difference between them is rather small. In addition, the threshold voltage of ZnO TFT is shifted under the positive or negative gate bias stress. However, the threshold voltage shift of IGZO TFT is smaller than that of ZnO TFT, and there is no threshold voltage shift for IGZO TFT under the negative gate bias stress. Therefore, IGZO TFT is more stable than ZnO TFT. In conclusion, IGZO thin film material is more suitable to be the active layer of the next generation of TFTs.关键词：ZnO TFT;IGZO TFT;property comparison;optical and electrical properties;shift of threshold voltage
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发布时间：2020-08-12 - 摘要：An evaluation method of LCD life was proposed in this paper. The basic experiment principle of accelerated life and experiment method were introduced, and the acceleration model was derived. Under the premise of distribution verifying, the accelerated life was calculated, and the life under any environment could be obtained by which the life evaluation of LCD is completed.关键词：accelerated life test;mean time between failures;distribution
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发布时间：2020-08-12 - 摘要：Transparent conducting Al-Ti co-doped zinc oxide films have been successfully prepared by DC magnetron sputtering. Microstructural, optical and electrical properties of TAZO films are investigated. The experimental results show that all the deposited films are polycrystalline with a hexagonal structure and a preferred orientation perpendicular to the substrates along the c-axis. When the sputtering pressures is 7.5 Pa, the lowest resistivity is 3.34×10-4 Ω·cm. All the films present a high transmittance of above 89% in the visible range. The sputtering pressures plays an important role on the microstructure and electrical resistivity of TAZO films.关键词：Al-Ti co-doped zinc oxide films;transparent conducting films;sputtering pressures;magnetron sputtering
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发布时间：2020-08-12 - 摘要：In 4-mask manufacturing process of the thin film transistor (TFT) liquid crystal display (LCD), multi-layer etch is a very critical process, because metal remain defect would happen after multi-layer etch, which will influence on the next insulator layer deposition, and induce layer broken. Conventional method for eliminating metal remain is to adjust multi-layer etch process, but there is no fundamental improvement. In this paper, the influence of data line etch time on metal remain after multi-layer etch has been researched, and it is found that metal remain could be fundamentally eliminated by adjusting data line etch time, and also could keep data line width in control.关键词：4-mask;multi-layer;etch;data line;metal remain
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发布时间：2020-08-12 - 摘要：A 'selective grow’ method for fabricating E-paper metal mould was approached. The microcup pattern with insulating material was made on metal substrate and the mould was obtained with follow-up process. First, Negative photo resists was coated on the metal substrate and the microcup pattern was exposed by a SLM LDW system. Second, after developing process, the metal mould was made by electroforming. The experiment results are according to the input parameters. This method is suit for larger format process, it will be an effective method for microcup mould.关键词：E-paper;microcup mould;LIGA
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发布时间：2020-08-12 - 摘要：Polysilicon thin film transistors have unique gate capacitance features, that is, the anomalous increase of gate-to-source capacitance in leakage region and gate-to-drain capacitance in kink region. Based on the Meyer model, taking leakage generation effect and kink effect into account, gate-to-source capacitance and gate-to-drain capacitance characteristics are modeled. The good agreement between simulated model results and experimental data confirms the accuracy and efficiency of this model.关键词：polysilicon thin film transistors;gate-to-drain capacitance;gate-to-source capacitance;model
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发布时间：2020-08-12 - 摘要：Novel Cr/Cu/Al/Cr thin film electrodes were prepared by DC magnetron sputtering and wet etching technology, in which Al thin film was used as the protective layer for Cu layer. The change of the crystal structure, surface morphology and electric resistivity of the thin films and electrodes before and after heat treatment were studied. The Al layer played a key role as an oxygen diffusion barrier layer, for its protection, the Cr/Cu/Al/Cr thin film still had good thermal stability when the heat treatment was below 600 ℃.Meanwhile, the oxidation diffusion from the lateral edge of the electrodes as the temperature increased caused the decrease of the conduction of the electrodes. The electric resistivity was increasing obviously after 500 ℃ heat treatment, and the oxidation region was expanded from the edge to the surface of the electrode. Nonetheless, the thin film electrode fulfilled the requirements of field emission device for its stable resistance when post annealing tempera-ture was 430 ℃, which was 7.2×10-8 Ω·m. Based on the new electrode, the FED device was fabricated for verifying its oxidation resistance.关键词：Cr/Cu/Al/Cr thin film;thin film electrode;microstructure;oxidation resistant
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发布时间：2020-08-12 - 摘要：This paper presents a driving scheme based on FPGA for the 17.8 cm(7 in) active matrix organic light emitting display(AMOLED) using μc-Si TFT technology. This scheme is easy to be implemented. It doesnt require external cache, and consequently the difficulty of PCB layout and system control is reduced. It presents a method connecting screen with IC to resolve the problem that it is not matching between AMOLED with LCD Driver IC. Architecture of the system and operating principle of each module within the FPGA are presented in detail. And the simulation results by computer and the results tested by oscillograph on the timing and controlling signals are provided. The results indicate this design can implement the dynamic video display on AMOLED with 64 gray scales.
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发布时间：2020-08-12 - 摘要：This paper presents a real-time edge detection system based on FPGA,using Veilog language to implement the system of data collection,storage and display.Aiming at the problem that the image edge detection affected by noise, this paper proposes a combination of median filtering and the improved Sobel edge detection preprocessing algorithm. Experimental results are compared with the results of the classic Sobel edge detection, which demonstrate the developed system has a strong image noise suppression and precise of edge extraction. It can be used in the fields that required for real-time,such as intelligent surveillance,identification and tracking and so on.关键词：FPGA;median filtering;SOBEL;edge detection
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发布时间：2020-08-12 - 摘要：Altera SOPC Builder provides the Nios Ⅱ processor and some common peripherals, but does not provide 320×240 LCD module interface and drive. Using the method of customized logic of SOPC Builder, liquid crystal display modules IP core which is developed by ourselves was added into the designing of SOPC,integrated into the system and programmed in the Nios Ⅱ IDE integrated development environment. It realized the interface design between Nios Ⅱ soft-core embedded processor and LCD modul.关键词：SOPC;NIOS Ⅱ;LCD;interface design
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发布时间：2020-08-12 - 摘要：A digital scheme of display based on FPGA was designed, with SRAM cache architecture of Ping-pong operation. And a design of interface system for 256 level gray scale display has been realized by the method of sub-frame, with digital time gray technology. Simulation and test results indicate that the system can give off suitable control signals and drive the screen. Besides, by means of Ping-pong operation, the responsive efficiency of display screen is improved efficaciously, and the application area is widened.关键词：time ratio gray;method of sub-frame;time gray;Ping-Pong operation
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发布时间：2020-08-12 - 摘要：A fast video segmentation algorithm based on background reconstruction is proposed for stereo video with static backgrounds. Firstly, the moving foreground areas are found out by the frame difference respectively. And then, the backgrounds shaded by foreground areas are reconstructed. At last, the moving foregrounds could be separated by comparing the backgrounds information with the current frame images and it could achieve the segmentation accurately. After that, two background images reconstructed from the left and right video sequences are matched in the initialization and the parallax image is saved, so that only the foreground parallax images are necessary to be updated. Therefore, the proposed method can improve image compression ratio and reduce storage. Meanwhile, the time for stereo matching is also decreased.关键词：video segmentation;background reconstruction;parallax image;stereo matching
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发布时间：2020-08-12 - 摘要：Based on the contrast sensitivity characteristics of human vision system and image features, a method was proposed to calculate the just noticeable difference thresholds of different frequencies of spectrum image. The thresholds was utilized to determine the watermark embedding and extraction. The watermarking scheme was designed, validated by experiment, and tested by attack, the results show that the peak signal noise ratio are all larger than 30 dB when JPEG compression quality factor is bigger than 30%, which indicates that the watermarks are well concealed. Normalized correlation value could still get to 0.653 9 under the case of compression quality factor of 20%, and the extracted watermarks could still clearly be seen intuitively.关键词：watermarking;digital image;human vision characteristics;just noticeable diffe-rence threshold;Fourier transform
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发布时间：2020-08-12 - 摘要：In order to get space camera image with good uniformity, a method of real-time TDI-CCD non-uniformity correction in orbit using XQ2VP40 FPGA is studied. Firstly the principle of CCD non-uniformity correction is analyzed, a two-point correction algorithm of half saturation gray and dark field gray is proposed, then the architecture of space cameras is introduced and correction algorithm utilizing FPGA is realized, finally the effect is proved by experimental result. The experimental results show that the method of CCD non-uniformity correcting is feasible, for the TDI-CCD whose non-uniformity is 5%, the non-uniformity is less than 1% after correction.关键词：in orbit;real-time;TDI-CCD;dark field;non-uniformity
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发布时间：2020-08-12
Table of contents
- 摘要：Abstract：LCD has gradually become the main trend in flat panel display, and its important component BLU(Back Light Unit), also play an decisive part. Nowadays, new-generation light source LED has been more and more applied in middle-large LCD field, such as LCD-TV, LCD-Exhibit screen, showing a very nice market outlook. This article designs a 46’ direct type BLU for semi-outdoor LCD. Using 0.5W High-Ra LED and without the packaging lens, the optical length can be within 25mm and the centre lightness can get 20000nits above. By optical, drive and thermal design, we got a direct type BLU design with feature of high lightness, nice display quality, good heat dissipation and low-cost, giving strong support to outdoor and semi-outdoor LCD-Exhibit use.关键词：Keywords: LED BLU(Backlight Unit);direct type;high lightness;LCD(Liquid Crystal Display)
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发布时间：2020-08-12 - 摘要：Sheet-like ZnO crystals were prepared by homogeneous precipitation two steps method without any metal catalyst, dry at 105℃, then anneal at 400℃, we can get the two samples with the two different heat treatment temperature. In order to investigate the influence of heat treatment temperature to sheet-like ZnO crystals, we used X-ray diffractometer, scanning electron microscopy, transmission electron microscope, ultraviolet-visible-near infrared spectrophotometer and fluorescence spectroscope to characterize the structure and optical properties of the two samples. The results reveal that the product is highly crystalline with hexagonal wurtzite phase and has the appearance of regular hexagon shape at (0001) plane. The crystallinity of sheet-like ZnO crystals enhanced and the energy band gap decreased with the annealing temperature increasing from 105℃ to 400℃. What’s more, the near band gap peaks were red shift in the photoluminescence spectrum with the increasing of the annealing temperature.关键词：optical properties
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发布时间：2020-08-12 - 摘要：The dependence of Zara and Rubbing Mura on Rubbing intensity has been studied. The experimental result show that, when Rubbing intensity is low, Zara easily occurs, and Rubbing intensity is high, Rubbing Mura easily occurs. By selecting the right Rubbing intensity, can reduce the incidence Zara and Rubbing Mura. In addition, through use FIB to observe the surface of the substrate, we found the reason of FFS product prone to occur Zara and Rubbing Mura关键词：LCD Zara Rubbing Mura
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发布时间：2020-08-12 - 摘要：Because of the limitations of cost and size of the navigation photo-electricity equipments, we need to get images and videos as clear as possible without changing the structure of navigation photo-electricity equipments. Thus, this paper introduces a method based on DSP image processing system to realize super-resolution reconstruction which realizes motion estimation by the united optimized algorithm of Fourier-Mellin and Keren firstly, and achieves super-resolution image reconstruction based on projection onto convex sets ,lastly realizes the method on DSP by optimizes the method based on the feature of DM642 without reducing the accuracy .This method improves the resolving power of the image system without increasing the size of system structure as well as enhance the identify ability of the system. Experiment results indicate that the detail of reconstruction image is clearer than that of the single frame interpolation image, and the average gradient and the information entropy also get improved.关键词：Imaging Reconstruction
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发布时间：2020-08-12 - 摘要：The portable data acquisition test system can conveniently and reliably realize the transmission and storage of the space remote data. This system adopts XILINX Virtex II PRO series FPGA as the data processing and control center. The storage and transmission control is also accomplished by FPGA. This system can work in two modes such as offline storage and on-line transmission. The structure of memory device is based on FLASH electronic hard disc, and it has the advantage of shockproof and portable and so on, which can meet the requirements of portable transfer. The input interface of the system is LVDS interface and optical fiber. In order to enhance the system's versatility, PC communication terminal is based on USB bus and Ethernet communication. By the experimental verification, the online data transfer rate of the system is up to 48MB/s and the speed of offline storage can reach 35MB/s.关键词：portable
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发布时间：2020-08-12 - 摘要：Transparent organic light emitting diodes were developed by using a multilayer oxide as a composite cathode. The device structure is ITO/ MoO3(10nm) /NPB(60nm) / Alq3(65nm)/ Al(1nm)/MoO3(1nm)/ Al(Xnm) /MoO3(30nm).The composite cathode is MoO3/Al/ MoO3 (MAM). A thin Al layer (1nm) was introduced as an interlayer between the Alq3 electron transport layer and the MAM electrode. On the one hand, the thin Al improves the interface flatness between electrode and organic layers, while improving the conductivity of the electrode. On the other hand, electron injection was greatly improved by form an Ohmic contact between electron transport layer and a thin Al. Then we obtained the OLEDs optimum performance by changing the thickness of Al in MAM. In the thickness of 18nm about Al we can obtained the highest brightness is 2297cd/cm2.关键词：Composite Cathode
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发布时间：2020-08-12 - 摘要：In the application of remote sensing cameras, the grayscale distributions of the transferred images are normally bad. In order to solve this problem, some researches are carried out. Firstly, the factors that affect the grayscale distribution are analyzed, and three methods are proposed for background subtraction and grayscale stretch based on the parameters of remote sensing camera’s imaging electronics. Then, the richness of gray levels of the three methods is formulated, and the optimal method is given. That is, analog stretch is implemented together with digital stretch and all the processes are based on the images with original bits of ADC. Then the lowest some bits are abandoned, and the images with the remaining bits are transferred down to earth. Finally, experiments are made based on an actual remote sensing camera’s imaging electronics system in laboratory. The results indicate that: the proposed three methods can all achieve the functions of background subtraction and grayscale stretch. The third method brings more gray levels to images than the other two, and leads to better imaging quality. Further, it can be applied in the remote sensing cameras of our country.关键词：Grayscale stretch
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发布时间：2020-08-12
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