最新刊期
期 5 ， 2012
- 摘要：Chiral nematic (N*) liquid crystal can reflect incident light selectively, and the reflective bandwidth is less than 150 nm commonly. Five N* liquid crystals were prepared from a nematic liquid crystal with negative dielectric anisotropy SLC10V513-200 and chiral compounds R1011, CB15. Their reflective spectra could cover with the entire visible spectrum. Polyurea microcapsules containing above N* liquid crystals were prepared by interfacial polymerization of isophorone diisocyanate (IPDI). By mixing same weight of five kinds of microcapsules together in surfactant OP-10 and IPDI, a gel was obtained. Applying an alternating electric field to an 80.0 μm gel film, the liquid crystal molecules in microcapsules would align parallel with the substrates. Curing monomer in the microcapsules with UV light and planar texture can be fixed, so the gel film which could reflect entire visible light wavelength range was prepared.关键词：liquid crystal;microcapsule;broadband reflection;negative dielectric anisotropy
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发布时间：2020-08-12 - 摘要：The piezoelectric inkjet printing of a polymer dielectric-poly (4-vinylphenol) (PVP), directly patterned onto Indium Tin Oxide (ITO) glasses, has been demonstrated. The electric characteristic of inkjet printed PVP dielectric films with various concentrations was studied. Capacitance, leakage current, and breakdown electric fields of the thin films were analyzed. The results show that with the applied voltage of 0~40 V, inkjet printed PVP films exhibit low leakage current density in the range of 10-11~10-8A/cm2, as a necessary reference for printing a high performance cross-linked PVP (CL-PVP) insulator.关键词：poly(4-vinylphenol);inkjet print;organic thin film transistor;dielectrics
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发布时间：2020-08-12 - 摘要：High-performance bottom-contact pentacene OTFTs with graphene source/drain electrodes by transferring and patterning CVD-grown graphene films in a room-temperature process has been developed. The AFM images show that the growth of pentacene grains was not affected by the electrode, because patterned graphene electrodes were significantly thinner compared to common metal electrodes. The output and transfer curve, on/off current ratio, threshold voltage and field-effect mobility of the device were obtained by electric mea-surements. The transfer curve showed an off-current level of ≈109 A and an on/off current ratio exceeding 103. The bottom-contact pentacene OTFTs based on graphene source/drain electrodes had a maximum field-effect mobility of up to 2×10-2 cm2 ·V-1 ·s-1.关键词：organic thin film transistor;layered graphene;patterned;Electrical properties
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发布时间：2020-08-12 - 摘要：Flexible displays have been attracted much attention as a next generation display for their ultra-slim, light weight, durable, and conformable properties. In order to fabricate flexible displays,the flexible sheets such as plastics and metal foils have been developed as a substrate material.Over the past decade, flexible substrates that have enabled the potential for wide-scale replacement of traditional glass substrates are critical to flexible displays development. This progress report provides an update developments in flexible substrates, which include polymer, stainless steel, ultra-thin glass, paper, bio-composite.Meanwhile,some novel solutions were summarized to overcome shortcomings in developing flexible displays.Finally, roll-to-roll technology for the development of flexible displays will be introduced, since it will allow their market implementation in flexible displays.关键词：flexible substrates;lifetime;roll-to-roll
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发布时间：2020-08-12 - 摘要：Based on the elastic theory of liquid crystal and variation theory, the capacitance characteristics of the strong anchoring hybrid alignment nematic (HAN) liquid crystal cell is studied considering the flexoelectricity of liquid crystal. Through numerical simulation using the Matlab software, the induced capacitance-voltage curves for different flexoelectric coefficients are obtained. With the increase of the applied voltage, the capacitance increases linearly for e11+e33≥0; however, for e11+e33<0, the capacitance begins to decreases and then increases with increasing the applied voltage. And, with the increase of absolute value of the flexoelectric coefficients, the influence of flexoelectric effect on the capacitance will be also enlarged.关键词：capacitance characteristics;hybrid aligned nematic;flexoelectricity;strong anchoring
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发布时间：2020-08-12 - 摘要：Silicon nitride thin films(SiNx) and hydrogenated amorphous silicon(a-Si:H)thin films were deposited by plasma enhanced chemical vapor deposition(PECVD)method. The effect of the PECVD pin on thin films was studied.The results show that SiNx thin films: thickness(dep. rate) about pin area is larger than that in no-pin area's; hydrogen content and [SiH/NH] about pin area is higher than that in no pin area's. However, a-Si:H thin films: thickness(dep. rate) about pin area is thinner than that in no pin area's; hydrogen content about pin area is higher than in no pin area's. The growth mechanism of thin films was discussed.
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发布时间：2020-08-12 - 摘要：The properties of polymer dispersed liquid crystal (PDLC) and stressed liquid crystal (SLC) are introduced; the construction, principle and preparation process of stressed liquid crystal tunable glass are introduced. The SLC tunable display glass is prepared under the process of expose with writing pattern, the area covered becomes transmissible and the other side is changed into scattering. It looks like a frosted glass in scattering state with pattern display without stress applied, and it can be changed into translucent state and the pattern disappeared at the same time after sheared applied. As a kind of other display mode, the novel function SLC light tunable glass can be applied in the products of moveable windows or doors without power consuming, there will be the application prospect in the fields of construct fit up engineering for the user of company, market, hotel and so on.关键词：polymer dispersed liquid crystal;stressed liquid crystal;light tunable glass;display;construct fit up engineering
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发布时间：2020-08-12 - 摘要：Based on the detailed analysis of AM-OLED panel electrical characteristics and various gray scale scanning methods, this paper presents the design method of high gray-scale video OLED(Organic Light-Emitting Diode Display) system. In the system FPGA is used as the core control device after the principle study to the AM-OLED scan and driving circuits. There are three main modules including the DVI data processing unit, the memory management module and the grayscale scanning control unit, and the subfield scanning method is applied in core imaging module. The DVI signal decoded can be displayed on the OLED panel real time (on line) via FPGA core controller, and also the gray scale is selectable, 256 or 64 gray levels. The video display system is implemented on the 240識GB(H)?320(V)QVGA OLED panel, 256 gray levels, and up to 60 Hz ~100 Hz frame frequency. There are 7 outputs in the power drive, which can be used to adjust the light of the OLED panel to fit the external environment, and this all completed the high gray-scale video OLED system.关键词：organic light-emitting diode;FPGA;gray-scale control;subfield scan;video display
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发布时间：2020-08-12 - 摘要：Cover glass for OLED encapsulation was made by wet etching technology. The impact of concentration of hydrofluoric acid, temperature, ultrasound and reactant on thickness and surface smoothness was studied. The best method to make cover glass was obtained: In the ultrasonic cleaner, the concentration of hydrofluoric acid was 40%, corrosion time was 15 min and the corrosion process cleared the reactant, then we got 0.177 mm smooth surface cover glass, which was coincident with the encapsulation standard of organic electroluminescent devices. Organic Light-Emitting Diodes were encapsulated using cover glass made by this method in a nitrogen atmosphere, the attenuation rate of luminance of these devices can be slowed down.关键词：OLED;wet etching;surface smoothness;ultrasound
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发布时间：2020-08-12 - 摘要：According to the problems of LCOS power consumption and the user experience for the existing microdisplay system, what is more, physical wires generally between the image transmitter and microdisplay or the use of the transmission efficiency not high of wireless image transmission protocol and so on, this work adopted the OLED microdisplay and wireless image data transfer protocol based on the non-compressed data WHDI, and used the FPGA EP2C8Q208C8 as the core control device.In the meantime, a host controller and OLED microdisplay driver and control module were designed.Thus the entire wireless OLED microdisplay system was designed and the realtime wireless transmission and display of high-definition images were realized.关键词：OLED microdisplay;WHDI;FPGA
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发布时间：2020-08-12 - 摘要：A design method for control unit of the TFT touching screen based on FPGA is described in this paper.Using a NiosⅡ processer built by FPGA,the corresponding point on the TFT and touching screens can be corrected automatically according to the programs in processer and the driver circuit between TFT screen and the ADS7843 chip.It is indicated that the control unit of the TFT touching screen based on SOPC technique has the advantages of quick response and exact touching,which can be compatible with all kinds of TFT touching screen,and it has good practicability and social value.关键词：FPGA;ADS7843;touching screen
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发布时间：2020-08-12 - 摘要：The control of display device is the foundation to realize good human-machine interface. Analog TFT LCD screen meets the requirements of the industrial machine in cheaper price and good display characteristics,so it is widely used in industrial machines.For 17.8 cm(7 in) analog screen, this paper puts forward the scheme that consists of STM32 and CPLD to achieve LCD control system based on single piece of SRAM as video memory, and analyzed the feasibility of the proposed scheme. The key problem of system design was discussed and parts of the program is given. The scheme saves cost and increases the reaction speed of the man-machine interface. It is of certain practical value.关键词：17.8 cm analog TFT LCD screen;STM32;CPLD;single video memory;DMA
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发布时间：2020-08-12 - 摘要：Horizontal Line Mura is one kind of defect during TFT-LCD manufacturing process. This defect will affect display quality seriously. After analyzing the profile of the metal layer and measuring the stress status of metal film, the root cause can be revealed. It shows that during deposition process of metal film on glass substrate, the stress of Mo layer between the center area and glass edge is different, and this caused the loose of Mo layer, which affect the capacitor between gate and source electrode, then cause display voltage shifting on the pixel. To solve this issue, by removing bottom Mo layer to adjust Gate layer stack ratio, the failure rate can be effectively reduced. And this is demonstrated by experiment.
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发布时间：2020-08-12 - 摘要：In order to segment each LED pixels from the image which is acquired by CCD and is used to brightness correction, a method based on optimal threshold segmentation with area constraint has been proposed. Based on optimal threshold method, taking prior information into account,an area constraint is introduced to restrain the range of threshold. Compared with traditional method, it is well done to avoid the LED region segmented connecting together. In the optimal threshold method with area constraint,the histogram of the captured image is generated,using the method of optimal threshold with area constraint, the optimal threshold is acquired. Finally, the optimal threshold method is used to segment the captured image. Experiments demonstrate that it is good to use this method to segment the LED pixels from the captured image, and also it can avoid the segmented region of LED pixels with a dense distribution connecting together.关键词：optimal threshold;area constraint;LED
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发布时间：2020-08-12 - 摘要：Aiming at the characteristics of the full-color LED display panel, a new LED display panel luminance uniformity assessment method based on Human Visual System (HVS) is proposed, which is validated by the experiment. The method uses CCD image sensor to get LED images. The image is divided into equal regions and each region's luminance characteristic factor, texture detail characteristic factor, and spatial location characteristic factor are calculated. Afterwards, three characteristic factors are integrated to be used as each region's luminance uniformity evaluation parameter, the dispersion of full screen regions can serve as the assessment criteria of the luminance uniformity and the assessment result is given objectively and accurately. Experiments show that this method is basically in accord with the subjective evaluation results. In addition, the method improves the consistency between objective evaluation and subjective evaluation about the luminance uniformity.关键词：LED display panel;human visual system;luminance uniformity
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发布时间：2020-08-12 - 摘要：Stability is an index to measure the quality of Switching Power Supply.The main factor that influences the stability of voltage-mode is caused by error amplifier. Compared to voltage-mode, current-mode improves a lot but introduces new factors, especially the sub-harmonic oscillation. This paper designed a Boost circuit which can insure the stability of output voltage and meet the requirements of EL lamp. A current comparator with enable signal is used in this paper to instead of error amplifier.Specific analysis and simulation results of the circuit are available in this paper. The circuit can achieve a response time about 25 μs, a reference current source about 4.3 μA, a load regulation rate about 6%, an output voltage from 70 V to 100 V, and this circuit can be applied to 19.4 cm2~38.7 cm2(3 in2~6 in2) EL Lamp. Above all, the circuit can act quickly, operate stably and be integrated conveniently.关键词：electroluminescent lamp driver;Boost circuit;stability;load regulation
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发布时间：2020-08-12 - 摘要：The paper introduces the principle of LED drive power with the single-stage Power Factor Corrector(PFC). The structure principle of constant-voltage source AC/DC with single-stage PFC is analyzed and the solutions of the questions related to the constant-voltage source with single-stage PFC is given.It is a key part to design of constant-current,the principle and design step of constant-current drive chip BP2808 are given,meanwhile,the manual dimmable LED is added,the multi-resonant self-excited oscillator consisted by NE555 is used to generate a fixed frequency and produce 0.09%<D<99.91% adjustable duty cycle pulse width modulation(PWM) output to adjust LED's light.The results show the design could achieve a wide range of adjustment duty cycle PWM pulse wave and it is satisfied with the requirements of the Power Factor Corrector,meanwhile,the high efficiency and low-cost is realized,the paper conform to the trend of the development of LED drive power.关键词：single-stage PFC Constant-voltage;constant-current driving;dimming LED
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发布时间：2020-08-12 - 摘要：Based on the national public administrations' demand for meteorological early warning, a specialized meteorological early warning information display terminal is designed. With inte-grating SMS technology, GPRS wireless communication technology, speech synthesis technology,LED display technology,embedded Linux technology and Qt software designing technology,the system realizes receiving,displaying and broadcasting remote meteorological warning messages. The task requirement, hardware design, soft ideas and the LCD interface driver based on Linux are described in details. Experimental results show that the system displays images distinctly, communicates with the control center stably and meets the design requirement entirely.关键词：meteorological early warning;embedded Linux;LED display;LCD driver
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发布时间：2020-08-12 - 摘要：Moving object detection is an important part of computer vision research. In order to eliminate the phenomenon of inanition, shadow and false edge, an novel algorithm of moving object detection based on five-frame-differencing and background edge-characteristic difference in the static background, is presented in this paper. Firstly, a background model is based on improved algorithm of Canny edge detection, the edge of motion object is gained by the background edge-characteristic difference, and then, it is combined with five-frame differencing to detect the motion object. Finally the complete and accurate object is extracted with morphologic filtering and connectivity detecting. The result shows the present algorithm runs quickly and veraciously and fits for real time detection.关键词：frame difference;edge detection;background edge characteristic difference;moving object detection
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发布时间：2020-08-12 - 摘要：A system structure of digital Computer-to-Plate is proposed. The multi-beam laser scanning imaging system, based on the data unit segmentation, is designed through analysis of the key technologies. The model of dynamic control of laser beam is established. The focusing optics with low distortion is designed. High-power laser modulator with rate up to 1 Mbit/s per beam is realized with the designed and fabricated grating light valve modulator. Therefore output intensity of multi-channel laser beam is stable and consistent. The dynamic feedback compensation circuit based on mechanical movement is proposed, which adjust scanning data rate adaptively. The consistency of plate scanning speed, the uniformity of pixel gray, the consistency of pixel size and pixel distance are ensured by using of adaptive compensation circuit technology. The laser Computer-to-Plate system with high-resolution, pixel reduction rate and repeatability is realized.关键词：laser scanning imaging;computer-to-plate;compensation circuit;beam dynamic control
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发布时间：2020-08-12 - 摘要：In order to solve the problem of detecting small dim targets in infrared images with the complicated air background, an improved algorithm based on image complexity and orientation gradient is put forward. The information entropy reflects the complexity of the image. The weighted information entropy with the variance and the change rate of local pixels suppresses both the inside and the edge of clouds. Since the image of the complexity is obtained, targets can be extracted by the means of multi-degree and multi-orientation gradient under the circumstance that the complexity of the background is higher than that of the targets. Experiments indicate that the algorithm can detect small dim targets effectively with complicated cloud background.关键词：image processing;small dim targets detection;complexity;weighted information entropy;orientation gradient
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发布时间：2020-08-12 - 摘要：In order to meet the requirement of miniaturization and portability of the image storage system for camera based on Camera Link interface, the hardware circuit was designed with a Virtex4 family Field Programming Gate Array(FPGA) from Xilinx company and a 6000 series Digital Signal Processor(DSP) from TI Company. First, under the control of FPGA, image data from Camera Link were cached in a SDRAM; at the same time, the image data which read from the other SDRAM were stored in other solid-state hard disks by ping-pang operation. Then the host computer connected with DSP through Fast Ethernet, under the control of the host computer, DSP acquired image data through External Memory Interface (EMIF) and sent it to host computer to realize real-time display or image playback function. The system that based on the scheme stored image successfully, past by the experiment in 640?480,100 f/s,10 bit monochrome. When the real-time display function is not needed, the designed system could accomplish image storage independently to meet the Base Camera Link type Camera portable storage requirements.关键词：image storage;camera link interface;FPGA;SDRAM controller;DSP
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发布时间：2020-08-12 - 摘要：In order to achieve the touch screen as the man-machine interface equipment, using SOPC technology, NiosⅡ processor system in FGPA was builted as a touch screen controller. Screen display and touch screen capabilities have been realized by writing NiosⅡ control procedures. The designed planning structure of Display Area has became a relatively common method to the information display and touch functions of the system. It can increase code reusability and versatility, simplify the program design process of display interface,and the system performance and development efficiency was improved.关键词：touch screen;NiosⅡ system;Planning of Display Area
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发布时间：2020-08-12 - 摘要：In order to compare the bullet automatically, the 3D texture information acquisition system of the bullet based on the structure light is established. Because the central axis and acquisition system axis y is difficult to completely overlap when we acquired three-dimensional information of bullets, so the corresponding coordinate rotation is need, especially when the bullet was deformed, it is unable to utilize the information that the bullet is approximate a cylindrical, this is very difficult for bullet extraction. Therefore this paper used the Gaussian approximation filter to get the mean line determined by Gauss filter, and then 3-D bullet information subtracts from mean line determined by Gauss filter, the bullet texture was extracted. Twelve order IIR digital Gauss filter is designed using the impulse response method, its amplitude transmission characteristic deviation is less than 1.38%, significantly better than the ISO11562 specified 2.5%. This method makes the bullet extraction process more simply, and the extraction result is more accurately, improving the accuracy of bullet comparison obviously.关键词：3-D texture;bullet feature;Gaussian filter;mean line by Gaussian filter
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发布时间：2020-08-12 - 摘要：Traditional UAS targeting technology uses space coordinate transformation theory to locate targets. It requires complicated calibration between INS benchmark, shock absorber base and optical turret coordinate. The accuracy of locating results is low due to the deviation of coordinate calibration and the latitude and longitude error of UAS. Errors brought by shock absorber can be eliminated thoroughly when INS and optical turret solid alliance installed in air pod. Using height value of airplane and laser distance measurement value, optical turret can work out the height of target in vertical down of view. It can also calculate GPS coordinate of target accurately using pixels relationship between target and GPS datum mark combined with the latitude and longitude of datum mark. Simulation test shows an accuracy result of ground target locating method based on GPS datum mark when air pod in vertical down of view status. Comparing with space coordinate transformation locating method, it saves complicated system calibration process, simplifies arithmetic formula, improves the locating accuracy and enhances the real-time feature of solution.关键词：air pod;vertical down of view;coordinate transformation;target location;GPS datum mark
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发布时间：2020-08-12
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