最新刊期
期 1 ， 2013
- 摘要：Polymer dispersed liquid crystal (PDLC) films with polyurethane matrix were prepared by the thermal polymerization-induced phase separation method. The electro-optical properties of the PDLC films prepared under different polymerization temperatures and monomer concentrations were studied. The relationship between the morphology of polymer networks and the electro-optical properties were investigated also. It was found that under the condition that the monomer content was 30%,the polymerization temperature was 343.2 K, the electro-optical properties of the prepared PDLC film were optimum.关键词：polymer dispersed liquid crystals;polyurethane;electro-optical properties;morphology of polymer networks
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发布时间：2020-08-12 - 摘要：The azo (—N=N—) group can have reversible trans-cis isomerization reaction under the appropriate wavelength light irradiation. The change of the azo molecular configuration affects fragile lattice structure of the blue phase liquid crystal and leads to the change of the lattice parameters, thus the selective reflection wavelength is also changed. Sometimes the change of azo molecular configuration can make the blue phase disappeared. In this paper several azo compounds were synthesized and doped in chiral nematic phase liquid crystal, then the temperature was changed to get blue phase I. The influence of selective reflection wavelength was studied and the azo compounds suitable for application were found. The reason of the difference was also discussed and the suggestion for further improvement was given.关键词：azo;light induced isomerization;blue phase;selective reflection wavelength
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发布时间：2020-08-12 - 摘要：The negative refractive index has been demonstrated theoretically in nematic liquid crystal consisting of randomly dispersive silicon carbide (SiC) core-shell microspheres in 13~13.2 μm mid-infrared wavelength range. Due to large permittivity of SiC induced by phonon polaritonic resonance, the collections of SiC microspheres produce negative permeability near 13.1 μm. By adjusting reasonable shell parameters,negative index liquid crystal is formed. Electromagnetic simulations show the mechanism for the negative permittivity and negative permeability.关键词：negative index;silicon carbide;nematic liquid crystal;mid-infrared
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发布时间：2020-08-12 - 摘要：4-dodecyloxy-phenyl-4',4″-diaminotriphenylamine (DPDTA) containing triphenylamine were successfully synthesized. Polyimides (PIs) containing triphenylamine units in the main chain were synthesized with the co-condensation of DMMDA, DPDTA and aromatic dianhydride 4,4'- oxydiphthalic anhydride (ODPA) by thermal imidization. The structures of the PIs were confirmed by FT-IR. The alignment behavior of PIs as liquid crystal alignment layers was also examined with polarized optical micrograph (POM). The properties of the PIs were characterized by TGA, UV-Vis and DSC etc. It was found that side chain density of PIs had important influence on properties of liquid crystal alignment film. Before rubbing, PI containing 25% DPDTA could induce uniform vertical alignment and a pretilt angle of 89.7°. The liquid crystal was not aligned on the surface of PI film which contained 10% DPDTA without the rubbing treatment. After the rubbing process, the pretilt angle of liquid crystal was 2.4, when PI film contained 25% DPDTA and the pretilt angle of liquid crystal was 1.8°, when PI contained 10% DPDTA. The transmittances of the PIs in 500~800 nm wavelengths are more than 80%, and their glass transition temperatures are above 230℃.关键词：polyimide;liquid crystal alignment;side chain;conformation;pretilt angle
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发布时间：2020-08-12 - 摘要：In the process of moving the voltage applied on hybrid aligned nematic liquid crystal cell (i.e. relaxation process), switching time of voltage is assumed finite, and then the voltage in the relaxation process is handled as exponential attenuation function of time. Based on above assumption, the distribution of the director in hybrid aligned nematic liquid crystal cell is analyzed by numerical simulation and this paper get the range of switching time impacting on the relaxation process.关键词：hybrid aligned nematic liquid crystal cell;finite switching time;relaxation process;dynamics theory
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发布时间：2020-08-12 - 摘要：According to the phenomenological theory of Landau-Ginzburg-de Genns and a simplified model of Lech Longa, this work got the system free energy within the four-order self-consistent cumulant expansion. The relationship between the specific heat and reduced temperature was researched. It is found that blue phase Ⅲ to isotropic phase transition ends at a critical point. So blue phase Ⅲ is a isotropic phase.关键词：blue phase Ⅲ;phase transition;reduced temperature
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发布时间：2020-08-12 - 摘要：Liquid crystal "blue phases" are highly fluidic,self-assembled, and three dimensional cubic defect structures that exists over narrow temperature ranges in highly chiral liquid crystals. Application of an appropriate chiral center may produce blue phase liquid crystals. Due to the unique property of fluorine, liquid crystalline materials with low viscosity, high birefringence (Δn), and high clearing points can be obtained by introduction of Fluoro-tolane. In this paper series of chiral compounds (one exception) containing 2, 3, 5, 6-tetrafluorodiphenyl acetylenes were synthesized. Their liquid crystalline behaviour was investigated by optical polarizing microscopy and DSC. The results show that 13 compounds show blue phase. Moreover, the slight difference of the chiral center results in appearance/disappearance of blue phase.关键词：fluoro-tolane;blue phase;chiral;liquid crystal;clearing point
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发布时间：2020-08-12 - 摘要：3,3'-dimethyl-9,9'-bianthracene was synthesized from 2-methyl-anthraquinone through two steps reactions, and its structure was determined by means of 1H NMR spectra and elemental analysis. The synthetic pathway has more advantages such as few reaction steps, high yield, easy purification and so on. Moreover, the effects on the reaction yield by different reductants and mole ratios were also discussed and its optical properties were characterized by the absorption and photoluminescence (PL) spectra. The results indicated that the maximum emission peak of the compound is at 447 nm, which is the typical blue fluorescence and its fluorescence quantum yield is 1.18 times than that of 9,9'-bianthracene.关键词：OLED;blue emitting material;3;3 -dimethyl-9;9'-bianthracene;synthesis
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发布时间：2020-08-12 - 摘要：Electronic ink microcapsules were prepared by the method of interfacial polymerization, stable solution of electrophoresis were produced by modified phthalocyanine green G as the green particles, span80 for the charge control agent, oil-soluble yellow for background color, PCE as a dispersion medium. Dispensability and particle size distribution of modified phthalocyanine green G in the electrophoresis medium were studied. SEM photograph is proved that when the octadecylamine mass fraction were 4%, dispersing effect of phthalocyanine green G in the PCE were the best. When E=50 V/mm, the particles in the microcapsules would be moved after the microencapsulation process is performed on the electrophoresis liquid.关键词：electronic ink microcapsules;interfacial polymerization;phthalocyanine green G
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发布时间：2020-08-12 - 摘要：Amorphous InGaZnO thin film transistors with bottom gate structure using transparent materials ITO and AZO as drain/source electrodes were fabricated by RF sputtering at room temperature. It was found that the fabricated TFTs exhibited good performance. For TFTs with AZO as electrodes, field effect mobility of 1.95 cm2/V穝, and on-off ratio of 4.53?105, as well as a threshold voltage shift of 4.49 V under positive bias stressing were achieved.关键词：thin film transistors;transparent electrodes;amorphous InGaZnO
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发布时间：2020-08-12 - 摘要：Redistributing parallax images by light directing element such as grating is one of the most important methods to achieve 3D display. This paper gives an introduction of how parallax barrier works to realize 3D display. The mathematical model of beams out of multi-period of barrier has been built to explore the roles played by barrier and width of sub pixel. Software to simulate the optical field in front of the 3D display has been developed. Both property of view zone and brightness of the display should be considered in order to get better 3D result. This study shows that the slit ratio for parallax barrier should between 0.2 and 0.3. In the process of prototype making the scale was set to 0.25. Particular bright backlight module was applied to compensating the lower brightness caused by lower scale and the display got a satisfactory result. The result has directive meaning for design of 3D display based on parallax barrier.关键词：autostereoscopic display;parallax barrier;slit ratio;view zone
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发布时间：2020-08-12 - 摘要：A two-point touch method for three-dimension space is proposed through introducing true three-dimension display and unmarked spatial orientation,while a two-point touch for true three-dimension display system is built. Interactive approach, which offers the solution of spatial orientation, tracking and gesture recognition, has been considered. Demonstrated in the experiments, optical-based two-point touch system meets the needs of human-computer interaction without any markers and sensors and changes of ambient light does not interfere with the operation of the human-computer interaction.关键词：true 3D;optical touch;spatial orientation;gesture recognition
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发布时间：2020-08-12 - 摘要：Portable naked-eye 3D device has many different screen sizes, in order to achieve a three-dimensional display on embedded system, which has different small-sizes of LCD, we need to do the image scaling and interpolation process based on the embedded system, so that the viewing of the left and right eye can be satisfied. In this paper,we researched the 3D image processing and designed a naked-eye 3D displayer based on Android system.The displayer can get physical pixels of the screen and the actual image resolution using Android to provide the functions,use low distortion linear scaling technology and columns interpolation fusion and complete the left and right format stereo video and image played. It was displayed correctly on portable device with specifications ordinary 2D LCD screen.关键词：nakedness-eye stereoscopic display;sub screen;image quality
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发布时间：2020-08-12 - 摘要：On the basis of the continuous elastic theory, the molecule directors two-dimensional distribution of a liquid-crystal blazed grating is simulated by difference iteration method. The electrodes are applied periodic voltages got by one-dimension spline method and adjustment. The liquid crystal cell is became a blazed grating with the optical path difference binary grating distribution by electrically controlled birefringence. The optical path difference curve and the phase delay curve are got. The simulation conclusion is verified by the experiment of the phase delay versus voltage calibration curve with quarter-wave plate method. The LC blazed grating photomicrograph under the orthogonal polarization is given.关键词：liquid-crystal blazed grating;molecule directors two-dimensional distribution;electrically controlled birefringence;binary grating
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发布时间：2020-08-12 - 摘要：Aiming at improving the detecting frequency and sensitivity, mountain-climb searching algorithm was used in projective capacitive touch-screen for the capacitance mea-suring of the sensor-electrodes. With the control of computer programs and some detecting circuits, the ordinary mountain-climb searching algorithm and the optimized one were rea-lized on a precise projective capacitive touch-screen. The analysis of the program running process indicates that, with the mountain-climb searching algorithm, the detecting frequency of a precise projective capacitive touch-screen can be improved for at less several times compared with the tradition detecting methods. Except this, the optimized mountain-climb searching algorithm can also improved the anti local disturb capability of the touch-screen. Test of sensitivity by line-drawing methods also indicates that the mountain-climb searching algorithm can effectively improve the detecting sensitivity of projective capacitive touch-screen.关键词：capacitive touch-screen;mountain-climb searching algorithm;detecting frequency;sensitivity
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发布时间：2020-08-12 - 摘要：A method of using liquid optically clear adhesive to bond a cover plate in the Liquid Crystal Display (LCD) former is developed, which improves the LCD display contrast and makes LCD clearly visible in sunlight environment. Through the improvement process, the production yield increases, quality is more stable and reliability higher. All of these make the LCD more competitive in the high-end and outdoor areas. The principle and method of sunlight readability of LCD are briefly described in this paper, as well as the implementation process and the problems of liquid optically clear adhesive bonding technology. The advantages and disadvantages of the technology and application prospects are elaborated and analyzed.关键词：liquid optically clear adhesive;LCD;sunlight readability
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发布时间：2020-08-12 - 摘要：LEDs have uniform problems include brightness aspect and color aspect, which would reduce the image quality of LED displays. This paper gives a method to correct the color gamut of LED displays. The method can solve the uniform problems, while correct the color gamut of LED displays accurately. This paper establishes a linear mathematical model of LED displays'colors, analyzing the target color gamut of LED displays. Then, the correction method with the target color gamut as LED displays'color gamut is introduced. Furthermore, white balance in color gamut correction method is introduced to fix the color coordinates of colors accurately. Experimental results showed that this method can correct the color gamut of LED displays into target color gamut accurately.关键词：LED displays;linear;color gamut;white balance
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发布时间：2020-08-12 - 摘要：In image processing, large image data need be exchanged among memories, so the transmission of image data is key link in image capture and processing system. EDMA is important technology in DSP that is used to realize the rapid exchange data, and it has the ability of transmission data that isn't dependent on CPU. In this paper, the video signal capture and processing system is designed based on TMS320DM642 chip of TI company. And in the system the EDMA data transmission mode is utilized to realize the high-speed and real-time transmission for the video signal data. The combination with the EMIFA of DSP and FIFO storage of the FPGA which is used in the data transmission is introduced in this paper, and the design of overall structure and the function of logic control are analyzed. Especially the principle,realization method and application based on the EDMA Ping-Pong data transmission mode is analyzed. In addition, the program of EDMA interrupt service is used in the image to process the moved image data, and the CPU is mainly used in video signal proce-ssing and system function control. This method not only improved the transmission efficiency of the data but also make the high-speed performance of DSP get full application, so as to lay a foundation for the real-time performance of video signal processing.关键词：EDMA;DSP;FIFO;data transmission;Ping-Pongx
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发布时间：2020-08-12 - 摘要：To solve the problem of excessive demand for remote network bandwidth when transmit color high-definition image through ethernet, this article gives a compression and transmission solution based on the combination of JPEG2000 Video Codec ADV212 and a FPGA with control logic. This system use a Bayer Pattern CMOS image sensor as data source, use the ADV212 to achieve fast high-quality image compression, the FPGA implements the entire system control logic, such as configuration on the ADV212, pre-distribution image, driving ADV212 under its timing and package the compressed stream. The experiments show that the system can guarantee to receive the image having a high peak signal to noise ratio, long-term stability 36 Mbyte/s image input conditions, and the system is small and easy to use, low bandwidth consumption and the compression ratio is adjustable and so on.关键词：ADV212;FPGA;JPEG2000;Bayer pattern;Ethernet
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发布时间：2020-08-12 - 摘要：A platform of real-time image processing is applied to scanning infrared-warning system. The platform is consisted of FPGA in Virtex-5 series of Xilinx and the high-speed DSP TMS320C6455 of TI based multi-core architecture. In order to improve the real-time of the system, a multi-channel scanning mechanism is introduced to the FPGA inner to replace the waiting mechanism adopted in traditional scanning infrared-warning real-time image processing system. The SRIO protocol is applied among the processors to attain high-speed communication, and the processed data is transferred to the master computer by PCI-e mode. Experimental results show that hardware platform design of this system meets the real-time needs and is more developed than the traditional one on delay time,false-warning and miss-warning.关键词：multi-channel scanning;infrared-warning;real-time image processing
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发布时间：2020-08-12 - 摘要：Aiming at the different texture characteristics of the forest and the smoke image, a smoke segmentation method about the improvement of differential box-counting(DBC)fractal dimension algorithm is proposed. Firstly, the improved algorithm expands the scope of child window based on the existing algorithm, calculates every pixel fractal dimension and analyses them. Then, it filters the pixels marked the smoke feature by choosing the fit threshold, it can realize smoke image segmentation. Finally, the expansive algorithm in the morphology is used to the connected processing. The experimental results demonstrate that the improved differential box-counting fractal dimension algorithm has a satisfying segmentation result.关键词：differential box-counting;fractal;image segmentation;mathematical morphology;smoke image
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发布时间：2020-08-12 - 摘要：To solve the localization that VGA display system based on computer or ASIC lacks portability and modification, a novel VGA display system to display any characters and images was designed under PS/2 keyboard control, which is based on user custom kernel SOPC technology. In FPGA, a 32-bits NIOS Ⅱ hardcore was built, main program was compiled with C language, and a AVALON BUS was used to connect the external drive controller and basic PIO interface, combined with VGA controller which composed by VGA timing module and buffers, the software part was completed through the above. Hardware platform is consisted of basic hardware circuit, external memory chips, PS/2 keyboard, VGA interface and UART circuit. The system finally achieved the migration of SOPC kernel and function of displaying character and image on CRT monitor under PS/2 keyboard control.关键词：SOPC;NIOS Ⅱ;VGA;PS/2;SDRAM
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发布时间：2020-08-12 - 摘要：This paper proposed a real-time rendering algorithm of scene in virtual endoscopy based on GPU which will meet the real-time rendering of high resolution and mass data in the imaging guided surgery (IGS). According to the characteristics of the virtual endoscopy rendering data that the lumen data is only a very small proportion (around 5%) of the total, the first thing to do is to finish the automatic segmentation of image and to get the segmentation data of lumen tissue. Then the divided data is loaded into the image memory once and make the rendering by ray casting algorithm. In addition, the multi-GPU loading is optimized. Finally, the real-time rendering of mass data is realized through the full use of rendering and parallel computing with GPU, such as 1 024?1 024?1 024.关键词：virtual endoscopy;GPU;ray-casting;load balancing
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发布时间：2020-08-12 - 摘要：In order to test the performance of organic light-emitting devices(OLEDs), an integrated photoelectric performance test system for OLEDs was designed and developed. The performances of the OLEDs (such as voltage-current, brightness, spectrum, chromaticity coordinates, lifetime, etc) could be measured in the same software. The communication routine between personal computers and the individual test equipments was described.The electroluminescent(EL) properties of OLEDs can be successfully obtained through simple control in a general computer. Using MFC(Microsoft Foundation Classes), a development tool of Microsoft Visual 2005, one convenient graphical user interface was successfully developed. Real-time display of the test process about the devices was realized through TeeChart (a graphical software developed by Steema). Furthermore, the characteristics of different devices could be compared by showing their curves in the same diagram. In addition, one CIE chromaticity coordinates assistant tool was developed, thus we manage to analyze the EL spectra and obtain the CIE chromaticity coordinates of the devices.关键词：OLED;integrated;test system
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发布时间：2020-08-12 - 摘要：The hardware platform of defects detection was composed for VFD display image by using PCI-1428 image acquisition card, CCD image sensor, camera and PC. VFD display image was acquired. Using software combination of LabVIEW and IMAQ-VISION, the system software were designed for image automatically montage, image defects detection, workstations control and database. Aiming at the characteristics of sampled VFD image, it was preprocessed by using gray-scale transformation, filtering, thresholding segmentation gray and image binarization methods to get good VFD image. Then the defects detection of VFD display image were completed, such as pictorial code, breaking codes, defects, flaws in letters' strokes. By test and actual operation,the experimental results showed that the system had a series of advantages. Detection speed and accuracy were high. Detection range was wide. Leaking inspection rate and false drop rate were lower. Detection results was ideal. It was achieved for the expected initial detection function and effect.关键词：vacuum fluorescent display;defects detection;image mosaic;module matching;flaws detect
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发布时间：2020-08-12 - 摘要：The luminance and chromaticity of monitors are measured through color luminance meters. Small-field optical filter color luminance meter is widely used in production line for its low-cost. Image color luminance meter, as a new product, is also a kind of optical filter color luminance meters. But it is large-field because of the different detector. Its structure, principle and performance are also different. Making performance contrast between these two kinds of optical filter color luminance meters helps estimating the image color luminance meter's quality. This paper makes a performance contrast between the two kinds' representative through principle analysis and experiment. It turns out that the performance of the image color luminance meter is no worse than the small-field optical filter color luminance meter.关键词：small-field optical filter color luminance meter;image color luminance meter;performance contrast
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发布时间：2020-08-12
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