最新刊期
期 1 ， 2010
- 摘要：Biaxial nematic liquid crystal is anchored by the grooves of a surface, so that one of the three directors is homogeneously fixed in direction of the grooves. This paper used a theoretical method proposed by Berreman,which the contribution of elastic origin to the surface energy of an uniaxial nematic liquid crystal. A formula was obtained which attributed the surface anchoring to the elastic distortion in the Berreman model, but in the biaxial nematics, it describes the distortion energy of the m director induced by the grooves of a surface, when the n director is anchored along the grooves. The stability of the n director around the grooves was studied. In one-constant model for each director, the rude condition is that the elastic constant of the n director is the maximum.关键词：biaxial nematic liquid crystal;surface groove;elastic distortion;stability condition
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发布时间：2020-08-12
Invited Paper
- 摘要：Benzofuran liquid crystals were synthesized in the base of alkylphenels by formylating chloroform. The intermediate compound which called substitute salicylie aldehyde would be produced. In this way, substitute benzofuran could be obtained.Thereby a series of benzofuran liquid crystals would be synthesized.The structures of liquid crystal compounds were confirmed by H1NMR and MS,the phase transition temperature was measured by DSC.Transition temperatures are Tmp=83.66 ℃;Tcp=145.42 ℃.关键词：benzofuran;liquid crystals;chloroform formylation;Suzuki coupling reaction
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发布时间：2020-08-12 - 摘要：Micro-Raman spectroscopy is performed to characterize GaN films grown on the patterned sapphire (0001) fabricated by wet chemical etching. The stress distributions are characterized by the frequency shift in the micro-Raman spectroscopy measurements. Residual stress state and carrier concentration in the mesa and wing region are assessed. The wing region shows lower compressive stress and less carrier concentration in comparison with mesa region. That is due to the interactions between sapphires and GaN as the result of diffe-rences in the coefficients of thermal expansion are excluded in the wing region by adopting maskless periodically grooved sapphire, thus less compressive stress and lower background carrier concentration can be achieved by this method.关键词：GaN;MOCVD;Micro-Raman spectroscopy
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发布时间：2020-08-12
Material Physics & Chemistry
- 摘要：The relations between the transverse electric field and the spiral pitch in the in-plane switching cholesteric liquid crystal cell under the different anchoring conditions are studied, and the influences of the surface anchoring states on the electric tune of the cholesteric liquid crystal spiral pitch are analyzed. The theoretical analysis shows that the electric field can tune continuously the reflected light color of the cholesteric liquid crystal under the in-plane switching mode, and the surface anchoring state of the liquid crystal cell has a great influence on the electric tune of the cholesteric liquid crystal spiral pitch. The results supply a theoretical support for the CLC color displays based on the electrically tunable pitch.关键词：cholesteric liquid crystal;electrically tunable pitch;anchoring energy;in-plane switching mode
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发布时间：2020-08-12 - 摘要：There are hundreds of defects happening during TFT-LCD process, especially during array process. Eroded array metal line is one of defects that can cause bright line or thin bright line defect. In this paper, this typical defect was analyzed by SEM, FIB, EDS and statistical software such as BO (Business Objects) and CIM (Computer Integrated Manufacturing). The results show that the defect occurred mainly when the metal layer was eroded by hydrochloric acid gas between Gate Etch process and Multi-Deposition process, and the leakage source of acid gas was identified. The hump in defect position was formed when vacuumizing during Multi-Deposition process. In addition,the emergency measures for this defect were also discussed.
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发布时间：2020-08-12 - 摘要：Organic thin film transistors(OTFT) have recently attracted considerable attention because of their potential application in the large area flexible display, flexible electronic storage, etc. Inkjet printing is an effective means of fabricating organic electronic devices because of its advantages such as simple process, low cost, digital photolithography and compatible with flexible substrates. In the paper, the progress of OTFT fabrication based on inkjet printing is described and some problems in the fabrication process of OTFT are also reviewed.关键词：inkjet printing;organic thin film transistor;organic circuit;patterning
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发布时间：2020-08-12 - 摘要：Polymer dispersed liquid crystal (PDLC) is a kind of new display material. It has a lot of advantages. Anchoring energy,as an important factor of PDLC,has a great influence on electro-optical properties. In this letter, a small amount of stearic acid (SA) was added into PDLC. With the increase of SA, the anchoring energy was reduced, which leads to a reduction in driving voltages and an improvement in the ON state transmittance. However, the ON state transmittance decreased when the concentration of SA exceeded 0.5%. Besides, with the decrease of anchoring energy, the hysteresis increased. It demonstrated that SA do reduced the anchoring energy and improved electro-optical properties of PDLC.
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发布时间：2020-08-12 - 摘要：Polymer dispersed liquid crystal (PDLC) films are particular devices consisting of micrometer-sized liquid crystal droplets dispersed in a polymer matrix. In this paper, PDLC films were prepared by photo-polymerization induced phase separation which were initiated by macroinitiator prepared by reversible addition fragmentation chain transfer (RAFT) polymerization. The influence of matrix molecule weight and polarity on the hysteresis effect of PDLCs was investigated. The results showed that parameters of the polymer matrix can significantly affect the hysteresis of PDLCs. Hysteresis increased as the molecule weight of the matrix decreased, and the decrease of the polarity of polymer matrix can efficiently reduce the hysteresis effect of PDLCs.关键词：polymer dispersed liquid crystal;hysteresis effect;molecule weight of polymer;polarity
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发布时间：2020-08-12 - 摘要：Nano-catkin films were prepared on Si substrates by means of electron cyclotron resonance microwave plasma chemical vapour deposition method in a hydrogen and methane mixture. The influences of substrates bias, CH4 concentration and deposition time on the nano-catkin structure of carbon film were investigated by Raman spectroscopy and scanning electronic microscope, respectively. The optimal deposition conditions were obtained by analyzing the images of nano-catkin film. The field emission characteristics were analyzed by using the current density versus electric field (J-E) curves and Fowler-Nordheim (F-N) curves. The threshold electric field of nano-catkin carbon films was reduced with increasing the CH4 concentration, at the same time emission current density was increased.关键词：electron cyclotron resonance plasma chemical vapor deposition;carbon-film of nano-catkin;field emission
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发布时间：2020-08-12 - 摘要：A self-assembled monolayer film of tolane was fabricated in aqueous solution by using silane coupling agent. Using this self-assembled monolayer film as homeotropic alignment layer of nematic liquid crystals (LCs), the liquid crystals could be aligned vertically on the quartz substrate. The procedure of self-assembly is simple and the film has perfect thermal stability. As a promising homeotropic alignment layer of LCs, this type of self-assembled monolayer film has much potential to be used in vertical-alignment display (VA-LCD).关键词：liquid crystal;homeotropic alignment;tolane;self-assembly;silane coupling agent
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发布时间：2020-08-12
Device Technology & Physics
- 摘要：Taking specific LED driving IC for example,the principle, advantages, disadvantages and performance improvement measures of peak current control, average current control and single-stage single-switch no-isolated LED driving circuit are discussed. The conduction EMI peak and the average test results of LED driving circuit using the jitter frequency technology is given. The work waveform and efficiency test results of LED driving circuit of average current control based on IR2540 are also given. The principle of the pulsed constant current supply LED driving circuit is briefly introduced. At last the meta-analysis about the development trend of LED driving circuit is done from the three aspects of constant current precision, efficiency and cost.关键词：high power;backlight;LED;driving circuit
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发布时间：2020-08-12 - 摘要：Controller of TFT-LCD based on FPGA was designed in this paper. Verilog HDL was used to generate the timing for TFT-LCD synchronization signal. By changing synchronization, it could support various interface of display systems. This display system had a good repartition.关键词：FPGA;TFT-LCD controller;Verilog HDL
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发布时间：2020-08-12 - 摘要：According to the requirements of the TFT color LCD display system, an overall soft-core design of the controller in the LCD display combined of system on a chip (SOC) and programmable system on chip (SOPC) technique is proposed to successfully develop the digital signal tester, which is based on an embedded Nios soft-core FPGA product. The programs to display points, maps and Chinese characters have a certain reference value to the designs of a variety of LCD instrumentation equipment.关键词：color LCD;SoPC system;direct memory access transmit;Nios soft core;Avalon bus
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发布时间：2020-08-12 - 摘要：Design technology of display device based on DisplayPort interface was proposed in this paper. The paper proposed the design technology,module structure,data type and arithmetic. The softeware and hardware were studied and developed, and the auto align arithmetic was implemented. Furthermore, the paper proposed the multifunction software, which can config the selection to match with hardware. The config of display device can be modified by RS232 or I2C communicate channel, it improved the flexibility of the software.The test results show that it meets the design specification.It is proved that developer can get better display effect to use DisplayPort technology.关键词：display port;image processing;control;decode
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发布时间：2020-08-12 - 摘要：OLED module and high performance 32 bit ARM920T series microprocessors was introduced,and applied to the display terminal of this control system. Meanwhile, according to the design of hardware interface circuit of ARM S3C2410 and OLED module, writing, compiling and loading the interface driver program in embedded Linux 2.4.18 were also explained in detail. The result shows that system parameters can be integrally displayed on OLED screen and the good effect has been achieved.关键词：embedded Linux;OLED;ARM S3C2410;driving design
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发布时间：2020-08-12 - 摘要：A video monitoring system is designed and implemented based on ARM and FPGA.With ARM9 processor as master controller and FPGA as coprocessor, the functions of real-time video acquisition and display are realized on the basis of constructing high-speed data transmission channel between ARM and FPGA and establishing lightweight graphics drivers on Linux OS.The experiment shows that the system can play video fluently which are PAL or NTSC formats with the advantages of excellent expansibility,high stability and fast response speed.关键词：video monitor;bus interface;graphics drivers
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发布时间：2020-08-12 - 摘要：In order to meet the requirements of industrial application site and terminal display of test system,this paper put forward one method,which uses DSPTMS320LF2407A controlled seven-inch liquid crystal display produced by Hitachi.The hardware interface circuit and the software drivers procedures of the method are introduced in detail. Software program is composed of C language,which has strong portability.It achieves the function of displaying coordinate system,text,graph and menu successfully.关键词：TX18D11VM1CAA;TMS320LF2407A;TFT8048;LCD screen;interface
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发布时间：2020-08-12 - 摘要：A bandgap reference (BGR) with adjustable temperature coefficient was designed. By controlling PTAT current, the temperature coefficient of reference voltage can be adjusted from positive to negative. Compared to traditional method, a two-bipolar transistor structure is adopted which could reduce the circuit area in chip and improve the layout symmetry. Furthermore, an OPAMP circuit was designed to improve the PSRR. The reference voltage could be adjusted in a wider adjustment with 16 levels. Implemented with 0.35 μm CMOS process, the Hspice simulation results showed that the temperature coefficient can be adjusted from -1.76 mV/℃ to +1.84 mV/℃ and the PSRR of the reference voltage reaches -110 dB at low frequency.关键词：bandgap reference;PTAT current;adjustable temperature coefficient;PSRR
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发布时间：2020-08-12 - 摘要：The hardware design and software design techniques of inner T6963C LCD module with MSP430 microcontroller is introduced,and the software design of the text mode,graphic mode,text attribute display are described.It gives examples of actual operation procedures.A good control has been realized.关键词：MSP430;T6963C;LCD display;SYB240128A
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发布时间：2020-08-12 - 摘要：A kind of dot-matrix LCD was applied to the solenoid detector as display terminal. A simple method was introduced to achieve multi-level nested menu display on the LCD screen and communicate with the micro controller through keyboards in the C language environment. The paper presented a compact and practical model of the process, and compiled some procedures used at every turn, which got across in the Weifu-E6000/L simulator successfully, and could make LCD display the real-time data accurately in the actual detection process, such as voltage, current, air pressure, which collected by solenoid detector. And this LCD can display some other related information about the solenoid detector nested, and the images are stable and clear.关键词：LCD;matrix of Chinese character;AT89C55;C language;nested menu
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发布时间：2020-08-12
Driving & Controlling
- 摘要：This paper introduces an optimal gray-scale scanning structure of flat panel display and clarifies the value of the sub-space strategy, which is dividing the whole plane into a number of different regions (sub-space), that ordered by the same weights sequences, separately scan them by the value of weight. Three different methods for the sub-space division strategy were proposed:traversal search, weight-symmetry iterate and genetic algorithm. The advantages and disadvantages of the three methods were compared with traditional methods, it can be found the new scanning strategy greatly increased the efficiency and reduced the operating frequency.关键词：gray;sub-space;genetic algorithm;weight-symmetry iterate
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发布时间：2020-08-12 - 摘要：This paper summarizes three main 3D volumetric systems and explains the principle and methods to carry them out,then analyzes the key technology of DMD and brings forward some example to use DMD as a volumetric 3D display engine. Those DMD engines have been proved by experiment and can satisfy some applications to process massive data in real-time, high speedily and precisely in different level.关键词：true 3D display system;digital micro-mirror device chipset;3D display engine
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发布时间：2020-08-12 - 摘要：Some commonly used image scaling algorithms were introduced, as well as a comparison among several algorithms. After weighing the algorithm complexity, zoom effects and FPGA logic resources, etc., the bilinear interpolation algorithm was chosen to achieve image scaling. This work focused on the bilinear interpolation algorithm and the method of FPGA hardware implementation, including image data buffer unit, interpolation coefficient generating unit, as well as the interpolation calculation unit. The realized results show that the bilinear interpolation algorithm and its hardware realizing modules achieve the desired results.关键词：image scaling;FPGA;bilinear interpolation
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发布时间：2020-08-12 - 摘要：As a kind of signal processing component, the scaler plays an important role in the flat panel display. Taking a video image scaler as researching target, a software verification platform suiting for VLSI chip design is introduced, whose testing vectors selection, testing vectors generation, results checking and architecture are explained thoroughly. Meanwhile, 1 200 testing vectors are verified adopting patterns automating generation method. A hardware emulation platform based on Xilinx developing board is presented, and the verification is also finished with loading hardware description language into FPGA. A testing environment for scaler has been implemented, and tape-out results shows that the scaler works well and meets the expectations.关键词：flat panel;scaler;software verification;hardware verification
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发布时间：2020-08-12 - 摘要：According to the actual requirements, a scheme of image focusing system based on OMAP processor was proposed, and the hardware design of interface with touch-LCD was introduced in detail. Then, the relevant Linux drivers were analyzed and two key problems in the application, the transform of image resolution and the form of touch-dot window, were discussed. Therefore, the inputting image data and focusing window could be displayed on the LCD proportionally. When the auto-selecting focusing window didnt meet the needs, touch screen could be used to readjust it. As a result, the quick manual selection and adjustment of focusing window was implemented, which met the special need of image focusing system in special field.关键词：focusing window;touch-LCD;OMAP processor;Linux drivers
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发布时间：2020-08-12 - 摘要：Focusing on the contradiction of the real-time image processing and real-time tracking in the real-time video signal processing system, a new real-time image processing system based on DSP and FPGA which can improve the system performance was introduced. DSP was used as the main processor to fast and effectively handle the complex recognition tracking algorithm because of its high-speed operation ability. FPGA was used as coprocessor to complete video image receiving, storing, preprocessing, etc. to make the design more flexibly. The centroid tracking and relevant track algorithm were adopted in the system. Experimental results showed that the system can track the moving targets in real-time quickly and stably.关键词：real-time image processing;DSP+FPGA;target tracking
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发布时间：2020-08-12 - 摘要：The traditional image scanning system is usually driven by a rotary motor, which transforms rotary motion into translational motion. There is transmission links, as a result, friction,clearance,mechanical deformation were introduced, the stability of the system during high-speed was undermined. In order to achieve high-precision reciprocating movement and obtain high-quality images, the image scanning system which was driven by the voice coil motor was designed, with the advantage of no lag, high response, high acceleration, high speed, easy to control, etc. During debugging the parameters of scanning controller, the graphical debugging interface based on Labview and GEL language was developed, shorten the development cycle, which can also be extended to other motor control debugging system.关键词：Labview;GEL;VCM;image scanning;control;high-frequency scanning
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发布时间：2020-08-12
Imaging Technology & Image Processing
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