最新刊期
期 6 ， 2015
- 摘要：This paper has synthesized four isothiocyanato-diphenyl acetylene liquid crystal compounds.Their structures were identified by IR,1HNMR,13CNMR,19FNMR,MS spectra.Their phase transition temperatures were tested by using differential scanning calorimetric(DSC) and polarizing optical microscopy(POM).It is found that all of the new compounds show nematic phase,and their phase transformation temperature was in the range of 105℃ to 137℃.Their birefringence are more than 0.47,which can be used as the effective components of high birefringence liquid crystal materials of liquid crystal raster.关键词：isothiocyanato;fluorinated biphenyl acetylene;high birefringence liquid crystal;synthesis
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发布时间：2020-08-12
Invited Paper
- 摘要：To improve the flicker in TFT-LCD,by studying the influence of Dry Etch(Nplus Etch) on TFT characteristics, the etching conditions (power and gas) were optimized, and the Photo-Ioff was reduced, then the flicker was improved.Experimental results show that when the main process conditions of Nplus Etch were:Source/Bias=4 k/5 k, Press=90 mT, SF6/O2=1.1 k/3 kmL/min and the conditions of AT Step were:Source/Bias=2 k/2 k, Press=100 mT, SF6/O2=3 k/3 kmL/min, the Photo-Ioff fell from 58.15 to 20.52 and the flicker fell from 15%-30% to 10% or less.The optimization of Dry Etching process has obvious improvement to TFT characteristics and flicker.关键词：dry etch;TFT characteristics;flicker improvement
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发布时间：2020-08-12 - 摘要：To achieve a light shutter with both high transmittance and perfect black, a kind of electrically controllable active liquid crystal light shutter was successfully fabricated where the reflection and transparent states can be readily switched on demand.The light shutter was based on three commercially available azobenzene-dichroic dye-doped cholesteric liquid crystals (DDCLC) with the pitch designed in the range of infrared region, and the effect of cholesteric pitch on their electro-optical characteristics was investigated in detail.Experimental results showed that the Vth, Vsatand ton were decreased with the increase of pitch, and among the samples the maximum Vth, Vsat and ton were only about 6 V, 20 V and 0.878 ms, respectively.Moreover, the transmittance of DDCLC films can reach more than 80%.Therefore, the proposed DDCLC films meet the requirements of the transparent display panel with high transmittance and visibility.关键词：cholesteric liquid crystals;azo-dichroic dye;pitch;electro-optical properties;light shutter
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发布时间：2020-08-12 - 摘要：The effect of plasma surface treatment on black matrix (BM) residue and substrate hydrophilicity is investigated in order to improve display performance of TFT-LCD with BM on array (BOA) structure.The size of remained BM particles and surface roughness are characterized by atom force microscope (AFM) and scanning electron microscope (SEM).Water contact angle and hydrophilicity of substrate are measured by the contact angle instrument, which gives the correlation between hydrophilicity and BM residue.Finally, the effect of O2 and He plasma surface treatment on BM residue is investigated.Experimental results indicate that the smaller water contact angle means the better hydrophilic and the less BM residue.After treatment with O2 and He plasma, the water contact angle of substrate is decreased from 17°to 3°and the surface roughness is decreased from 3.06 nm to 0.69 nm after BM process.AFM morphology images show that BM residue is completely eliminated from the substrate.关键词：plasma treatment;hydrophilicity;contact angle;Black Matrix
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发布时间：2020-08-12 - 摘要：When the STN liquid crystal alignment agent is filmed and thermoformed on the surface of glass substrates in industrial production, it is necessary to clean the substrates with solvents. In the process of cleaning, the film often peels off from its substrate. To tackle this problem, an additive is required to improve the adhesive performance of the agent without sacrificing its viscosity, outlook, pretilt angle and hardness. A silane additive N-[3-(trimethoxysilyl) propyl]aniline (Y9669) is introduced into the agent. Five solutions were prepared for the agent in mixture with the additive in different proportions. The viscosity, outlook, pretilt angle, hardness and etc. of the solutions were examined. The STN liquid crystal alignment agent system reaches its best overall performance when the silane additive Y9669 is added 0.5% equal to the solid content of the agent. The silane additive Y9669 could improve the adhesive performance to the substrate with almost no impact on the other perfor-mances of the agent.关键词：polyimide;liquid crystal alignment agent;silane additive;adhesive performance;pretilt angle
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发布时间：2020-08-12
Material Physics & Chemistry
- 摘要：Using radio frequency magnetron sputtering, p-type N doped Mg0.13Zn0.87O film was deposited on quartz substrate with Mg0.06Zn0.94O target.The film has resistivity of 42.45Ω·cm, Hall mobility of 0.40 cm2·V-1·s-1 and carrier concentration of 3.70×1017/cm3.The stability of p-type conductivity in this film preserved in room temperature air ambient was studied.It is found that the resistivity increased and the carrier concentration decreased with time.The film transformed from p-type to n-type semiconductor with resistivity of 85.58Ω·cm, Hall mobility of 1.61 cm2·V-1·s-1 and carrier concentration of 4.53×1016/cm3 after preservation for five months.The film transformed to p-type semiconductor again after thermal annealing under 10-4 Pa.It can be deduced that, the p-type film reverts to n-type conductivity because hydrogen and water were adsorbed by film to create shallow donors in air ambient.关键词：radio frequency magnetron sputtering;thin MgZnO films;p type;stability
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发布时间：2020-08-12 - 摘要：Indium-tin-oxide (ITO) films as transparent conductive are applied on TFT.This paper studied the influence of ITO contamination of gate insulation & a-Si layers and TFT on electrical characteristics.The obtained samples were characterized by secondary ion mass spectroscopy (SIMS) and electronic parameter measurement (EPM).The result shown on the gate insulation & a-Si layers had been contaminated by ITO in the PECVD equipment, and the contamination can make TFT electrical characteristics become worse.ITO concentration in process equipments plays an important role in the TFT electrical characteristics.Therefore, we suggest the gate insulation & a-Si layers should be deposited in independent equipment and the PECVD equipment should be cleaned periodically. Thus, the ITO contamination can be reduced and TFT electrical characteristics can also be improved.关键词：TFT;PECVD;gate insulation layers;active layers;a-Si films;ITO;electrical characteristics
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发布时间：2020-08-12 - 摘要：The sample of stressed switchable glass is prepared.While the sample is being applied on the sheared stress by the sheared device, it is in the scattering polarized state.The peculiar characteristic of visual angle that transmittance of light is higher in the direction of sheared force is observed.Through establishing theoretical model and testing the curve of the light transmittance changing with the incident angle, the comprehensive expression of transmittance of scattering polarization glass and the relationship between the tilt angle of liquid crystal and transmittance of liquid crystal in the sample is obtained.The simulation results show that the theoretical expression can basically describe the sheared liquid crystal scattering polarization glass properties.关键词：sheared liquid crystal;scattering polarization glass;transmittance;viewing angle characteristic
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发布时间：2020-08-12 - 摘要：In order to improve the balance of carrier injection, a high electron mobility material Bphen and Bphen:Cs2CO3 are introduced in OLED devices respectively based on the structure of ITO/MoO3/NPB/Alq3/Cs2CO3/Al. The experiments study the effect of Bphen and Bphen doping Cs2CO3 on the OLED devices of luminescence brightness, current density and efficiency by changing the thickness of Bphen and the volume concentration of Cs2CO3doped in Bphen. Experimental results show that Bphen or Bphen:Cs2CO3 used as electron transport layer both can improve electronic injection and the performance of devices. Compared with the devices without Bphen, adding 25 nm thickness Bphen as electron transport layer can improve the device of electron injection, which increase the maximum current efficiency by 112%.Adding 5 nm thickness Bphen:Cs2CO3(15% volume concentration doped) as electron transport layer can reduce the electron injection barrier, which increase the maximum current efficiency by 27%. However, changing the doping layer thickness has little impact on the device's electron injection. This method can be used in cathode decorate of OLED devices and play a certain role in promoting the devices' performance.关键词：electronic transport layer;Bphen;Cs2CO3;OLED
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发布时间：2020-08-12 - 摘要：Adopting semi-transparent thin silver as cathode and UV-ozone surfaced-modified thick silver as anode, top-emitting organic light-emitting device (TEOLED) on silicon substrate with high luminance and efficiency was fabricated. The maximum current efficiency was 4.9 cd/A when the voltage was 9 V and the luminance reaches 14040 cd/m2 at 17 V. The device structure is further optimized by increasing the doping concentration and the anode thickness.By optimizing the device structure, a TEOLED with high current efficiency (11 cd/A at 10 V with luminance of 21748 cd/m2) had been reported. Due to the microcavity effect, the efficiency and luminance of TEOLED are relatively high, but the blue-shift of the resonant wavelength (RW) with increasing view angles is obvious. By employing the suitable emitting material, the blue-shift of the RW is nearly negligible in our device when the viewing angles moved from 0°to 75°.关键词：top-emitting;organic light-emitting devices;surface-modified;luminance;current efficiency
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发布时间：2020-08-12
Device Physics & Device Technology
- 摘要：In the paper, we show the reasons for light leakage in the nematic liquid crystal (NLC) cells with bulk defect structure in the dark state and the influence of the anchoring conditions on it. Firstly, we give three models of NLC cells with different director distribution at the initial state. Secondly, based on the Landau-de Gennes theory, we calculate the defect dynamics of the director field and get the director distribution in the cross-section of the cells at equilibrium state. Finally, we express the director distribution in the form of light transmittance with Jones Calculus. Without applied field, the simulation results indicate that the cells with bulk defect have spontaneous twist structure under the condition of L2/L1 ≥ 1(K22/K11 ≤ 2/3), which leads to light leakage of the cells. The intensity of light leakage varies with defect structures and anchoring conditions at the boundaries. Our models can explain the light leakage in the NLC cells induced by the bulk defect in the dark state, and the results show a good agreement with the phenomena found in the process of industry manufacture.关键词：bulk defect structure;light leakage;Landau-de Gennes theory;spontaneous distortion
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发布时间：2020-08-12
- 摘要：An OV9712 from Omnivision company was chosen as image sensor for design of automotive camera module.In order to improve the communication speed of high definition image signal, a set of chips from TI, DS90UB913Q and DS90UB914Q as serializer and deserializer was adopted to coding and decoding the LVDS differential signal of high definition image.Finally, the design realizes the function of high-speed and full-duplex communication by LVDS.The experimental result shows that the application of these chipsets improves the image quality of automotive camera module greatly.关键词：OV9712;DS90UB913Q/DS90UB914Q;FPD-Link III;full duplex communication
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发布时间：2020-08-12 - 摘要：In order to control and manage extreme ultraviolet camera, the electronic control unit based on FPGA is designed. This system adopts FPGA as processing and control core. It communicates with signal processing subsystem through RS-422 and receives science data with LVDS. It communicates with CPU through data bus. The radiation-hardened and cross backup redundancy design is adopted in order to improve the reliability of the system. The electronic control unit tests for extreme ultraviolet camera show that the function and performance of extreme ultraviolet camera are qualified. It plays an important role for extreme ultraviolet camera in-orbit operation.关键词：extreme ultraviolet camera;electronic control unit;FPGA
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发布时间：2020-08-12 - 摘要：To promote the integration of mapping information obtained, image interaction and display are realized based on the dual-core ARM+FPGA hardware architecture in this paper by taking full advantage of the parallel processor FPGA (Field-Programmable Gate Array) and the high-performance ARM processor.The real-time image display is realized based on Qt graphical interface and the driven design of FPGA FIFO (First Input First Output) is completed in the Linux 2.6.36 kernel which uses Linux operating system as the software platform, ARM11 as the core of embedded hardware processor and FPGA as the coprocessor.The test results show that it could achieve high speed VGA (640×480) format image interaction between ARM and FPGA with the maximum frame rate of 26 fps and the maximum transmission bandwidth of 182 Mbps.This system not only has the advantages of small volume, low power consumption, low cost, but also has good performance of stability and functionality.Moreover, it could meet the real-time requirements for the aerial remote sensing system.关键词：ARM;embedded Linux;FPGA;device driver;image display
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发布时间：2020-08-12 - 摘要：To realize the composition of the serial port information such as time and azimuth value on the fixed line of the digital video signal, the communication data and digital video signal composition system has been designed. Based on FPGA, the serial port data is received and processed by the FIFO module, and a fixed line signal is extracted. The communication data and video signal composition is realized, and the composition data is output under the frame valid signal. The communication data and digital video signal composition system based on FPGA realized the data composition function. In the experiment, the baud rate of the communication data is 230.4 kbit/s, frame rate of the video signal is 50 Hz, pixel size is 1024×1024, the communication data is composed in the last line of one frame video signal correctly, the system works stably and the work status is good. The communication data and digital video signal composition system based on FPGA realizes the data composition in the simplest hardware system, meets the requirements of the image processing and display system, has broad engineer meaning.关键词：video data;communication data;composition;FPGA
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发布时间：2020-08-12
Driving & Controlling
- 摘要：Various distortions will be introduced to images during different image processing procedures, and the assessment of image quality has become a hot topic. According to the fact that the traditional pixel-difference statistics-based PSNR method and structural similarity method cannot correlate well with human subjective evaluation, a novel image quality assessment method via Riesz-Transform based structural similarity is proposed. The method firstly applies 1st-order Riesz-Transform and 2nd-order Riesz Transform to the reference image and distorted image, and 5 groups of corresponding features maps are obtained to produce 5 similarity maps and 5 weighting maps. Then the average-method fusion is performed to get the final similarity map and weighting map. Lastly, the luminance comparison of the original reference image and distorted image is considered to get the final image quality index. The experiments on the LIVE database indicate that the proposed method has high prediction accuracy and consistency on all 5 distortion types. It also outperforms the SSIM method under cross-distortion conditions and the PLCC value and SROCC value reach 0.9482 and 0.9532 respectively. Compared with other state-of-the-art methods, the proposed method owns good predictive performance, which indicates better consistency with human subjective perception.关键词：image quality;structural similarity;Riesz-Transform;feature map
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发布时间：2020-08-12 - 摘要：This paper develops an automatic segmentation method of lung image using two dimensional Otsu method based on particle swarm optimization in order to reduce operation time. Aiming at the shortage of the traditional two dimensional Otsu based on particle swarm optimization, which the calculating quantity is large and standard particle swarm algorithm is easy to fall into local optimum, an improved lung segmentation based on 2D Otsu optimized by PSO is proposed in this paper. Using the grayscale-gradient two-dimensional histogram, not only reduces the amount of histogram's calculation, but also narrows the searching area of particles. The algorithm uses the improved PSO which based on diversity of particle symmetrical distribution to search optimal threshold. In the process of algorithm, the region filling algorithm is used to remove background in order to make the threshold segmentation of lung better, and the morphology operations to remove noise and repair holes which in the target image. The threshold segmenting time in this algorithm is about 0.2 s, increased about 16% than the speed of the traditional Otsu threshold segmentation optimized by PSO,the size of the CT images is 512×512 pixels in this experiment. The segmentation algorithm in this paper can segment the lung in CT image automatically, not only ensures the accuracy of the segmentation, but also improves the speed of the segmentation in comparison with conventional algorithms.关键词：two-dimensional Otsu;improved PSO;region filling;morphological operations;automatic lung segmentation
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发布时间：2020-08-12 - 摘要：This paper offers a high precision imaging method for rotating LED based on DDS algorithm. It transforms the problem of rotating LED space imaging for three-dimensional object into Array signal generation problem and outputs high precision array signal by introducing DDS algorithm, realizing high accuracy spatial imaging of rotating LED stably for a long time. Simulation experiments and line array rotating LED imaging platform experiment results show that, compared with the existing method, this method is simple, reliable, and stable.关键词：DDS;rotating LED;high precision imaging
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发布时间：2020-08-12 - 摘要：To reduce the impacts of the variations of expression and illumination, a novel face recognition method based on sub-pattern two-directional two-dimensional linear discriminant analysis(Sp-(2D)2LDA) is presented in this paper. Firstly, Sp-(2D)2LDA divides the original images into smaller sub-images and keeps the spatial relationship between the sub-images. Secondly, it simultaneously applies 2DLDA to the subsets of the training samples in the row and column directions to extract local sub-features. Finally, the sub-features are synthesized into global features and nearest neighbor classifier is used for classification. The experimental results on Yale and ORL face databases show that the proposed Sp-(2D)2LDA method effectively reduce not only the dimension of the eigenvectors, but also the influence of variations in illumination and facial expression. Thus, the proposed method has better classification performances than the other related methods.关键词：face recognition;feature extraction;two-directional two-dimensional linear discriminant analysis;sub-pattern two-directional two-dimensional linear discriminant analysis
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发布时间：2020-08-12 - 摘要：After the image decomposition with NSST, the high-frequency coefficients have a large amount of data and greater sparsity. In order to obtain fusion results rapidly, an image fusion algorithm based on Non-subsampled Shearlet Transform (NSST)combined with Compressed Sensing (CS) is presented. Firstly, the source images are decomposed with NSST; secondly, the high-frequency sub-band coefficients of the decomposed images are compressed, fused and reconstructed by CS; then, based on local area variance and local area energy, the low-frequency coefficients was fused; finally, the inverse NSST is used to get the final fused image. Because only the compressed values of the high frequency coefficients are fused, the image fusion effects can't be affected, and the running time of the algorithm can be reduced. In this paper, the multi-focus image, medical image and infrared and visible images are used to verify the effectiveness of the algorithm. The simulation results indicate that this algorithm can achieve the fusion of the image without prior knowledge of the original image. When the image size is larger, although the fusion image quality is sacrificed, it can significantly improve the speed to reduce the time cost and hardware requirements. The algorithm provides an idea on how to satisfy the real time requirements in the fusion system, which has a great practical value.关键词：image fusion;non-subsampled Shearlet transform;compressed sensing;local area variance;local area energy
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发布时间：2020-08-12 - 摘要：Presence of metal artifacts in computed tomography (CT) is a major reason of degradation of image quality. In this work, a novel metal artifact reduction (MAR) algorithm using prior interpolation was developed to suppress metal artifacts in CT images. The prior image was generated by pre-filtering, bone extraction, and soft tissue restoring procedures. This prior image was then reprojected, and the estimation of surrogate data in the metal traces could be performed via the reprojections. Next, the corrected experiments were conducted on digital phantom and clinical data respectively. The simulation experiment shows that results stem from prior interpolation MAR (PI-MAR) have higher similarity of ideal phantom than those from linear-interpolation MAR (LI-MAR) and Normalized MAR (NMAR) algorithms. Clinical experimental results demonstrate that the new algorithm can successfully suppress metal artifacts and clearly restore anatomical structure close to metallic implants. Moreover, the quality of reconstructed images can be greatly improved by the proposed algorithm.关键词：metal artifacts;prior image;pre-filtering;soft tissue restoring
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发布时间：2020-08-12 - 摘要：To evaluate and compare the crosstalk phenomenon more directly in stereoscopic displays, single value evaluation method which combined with image content is applied to gray-to-gray crosstalk. The proposed average gray level transitions concept chooses a group of representative three dimensional (3D) images and applies statistic analysis to derive probability of each gray level transition which also exist in matrix form. The single value evaluation of gray-to-gray crosstalk is using average gray level transitions matrix to weight gray-to-gray crosstalk matrix and the values of weighted averaged gray-to-gray crosstalk matrix are added as the final single value for crosstalk evaluation. The proposed single value evaluation method of gray-to-gray crosstalk fully considers the effect of 3D image content on crosstalk, and the derived single value crosstalk evaluation is more objective and precise. The investigation result helps with the optimization of crosstalk and the improvement of visual comfort.关键词：D display;gray-to-gray crosstalk;single value evaluation;average gray level transitions
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发布时间：2020-08-12 - 摘要：With the accelerated developing of hospital digital medical, the amount of medical imaging data grows dramatically, which affects the data storage space and access speed. This paper proposes a new design which uses different scales dictionaries of MOD, K-SVD, ILS-DLA, RLS-DLA for digital imaging and communications in medicine (DICOM) image compression storage and restore methods based on dictionary learning. Compared with the traditional algorithms JPEG and JPEG2000, the proposed method has better performance, especially when the dictionary scale is smaller. For example, when the compression ratio is 20, using 4×4 dictionary scale, the peak signal to noise ratio (PSNR) of the proposed method is 7.8 dB higher than that of JPEG, and 1dB than JPEG2000.关键词：dictionary learning;image compression;DICOM image;dictionary scale
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发布时间：2020-08-12
Imaging Technology & Image Processing
- 摘要：Based on Field-Programmable Gate Array (FPGA), a high precision time keeping technology is proposed. Combined with high precision constant temperature crystals and BD/GPS dual-mode synchronous, standard second pulse signal is received based on statistics. If navigation satellite loses the connection, FPGA will set the pounding threshold of crystal pulse according to average value and variance to simulate producing highly precision second pulse so that cumulative error can be eliminated. Experimental results show that timing system error is less than punctual 250 ns in one hour which fully meets the requirements of time keeping of the timing system in the power systems, range systems and other systems.关键词：FPGA;dual-mode;connection losing;time keeping
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发布时间：2020-08-12 - 摘要：The response time of infrared touch airborne display is analyzed and tested, and the optimization method of response time is introduced to meet the needs of users.The response time is counted in VC++.According to the touch process and the count result of response time, the response time can be reduced through increasing RS232 signal Baud rate, interrupt method and merging tasks.The optimized response time is 89.5 ms, which reduces 37.5 ms than before.The optimized response time ensures the aviator can see general picture in time.关键词：multifunctional display;infrared touch display;response time;time-delay optimization
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发布时间：2020-08-12 - 摘要：According to the experiments analysis about the uniformity of luminance and stability of contrast of grating displayed on LCD display, a method is proposed to measure contrast sensitivity characteristics of human visual system by displaying the grating using LCD. The contrast sensitivity characteristics of 48 youngers who detect gratings with three kinds of luminance were measured, and it is compared with the typical measurement methods and results. The results show that the measuring method is effective, practical, simple and easy to measure the contrast sensitivity characteristics of human visual system.关键词：human visual system;liquid crystal display;contrast sensitivity;spatial frequency
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发布时间：2020-08-12
Measurement Technology
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