最新刊期
      期 1 ， 2018

        Material and Device

      • Jing ZHANG,Xuan ZHOU,Si-bo CHEN,Kai LIU,Zhi-dong ZHANG
        Vol. 33, Issue 1, Pages: 1-13(2018) DOI: 10.3788/YJYXS20183301.0001
        摘要：Based on Landau-de Gennes theory, we investigated the flexoelectric effect and spontaneous distortion effect within three different domain walls in parallel aligned nematic liquid crystal system influenced by electric field, using the relaxation iterative method. Our results show that, the domain walls in our system exist in the range of 0.2 ≤ E/E0 ≤ 1.2(E0=1.45 V/μm). With one elastic constant approximation, flexoelectric effect with opposite direction of electric field will influence the twist angle of do  
        关键词：Landau-de Gennes theory;domain walls;elastic anisotropy;flexoelectric effect;spontaneous distortion effect   
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        发布时间：2020-07-06
      • Mao-zhou CHEN,Hai-tao DAI,Dan LUO,Xiao-dong ZHANG,Chang-long LIU
        Vol. 33, Issue 1, Pages: 14-22(2018) DOI: 10.3788/YJYXS20183301.0014
        摘要：This paper investigated the improvement of random lasing properties based on dye-doped polymer stabilized liquid crystals (DDPSLC) by doping Ag and ZnO nanoparticles (NPs) with different concentrations in capillaries, in order to expand new applications for this device. At first, DDPSLC samples with different dye doping concentrations were prepared in capillary tubes to select an optimum DDPSLC system for doping NPs. After selecting the optimum DDPSLC, some Ag NPs and ZnO NPs with different concentrations w  
        关键词：nanoparticles;dye lasers;liquid crystals   
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      • Zhen-jie LI,Rui YUAN,Ting-ting SUN,Ji-liang ZHU,Wen-jiang YE
        Vol. 33, Issue 1, Pages: 23-29(2018) DOI: 10.3788/YJYXS20183301.0023
        摘要：The phase modulation of the liquid crystal microwave modulator depends on the distribution of the liquid crystal molecular director. The distribution of liquid crystal director is not only affected by these factors such as the pretilt angle of the liquid crystal molecules and the anchoring energy on the surface of the substrate. The flexoelectric effect of the liquid crystal material also affects the liquid crystal director distribution. Based on the elastic theory of liquid crystal and the finite-differenc  
        关键词：flexoelectric effect;microwave phase modulation of liquid crystal;microwave phase shift per unit length;elastic theory of liquid crystal;the finite-difference iterative method   
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        发布时间：2020-07-06
      • Wen-ming LV,Hong-xia ZHANG,Xiao-min SONG,Da-gong JIA,Tie-gen LIU
        Vol. 33, Issue 1, Pages: 30-37(2018) DOI: 10.3788/YJYXS20183301.0030
        摘要：Tunable liquid crystal (LC) lenses are expected to have potential applications in image processing, optical communication, machine vision and 2D/3D switchable display due to their advantages of compact structure, low power consumption, good stability, and simple fabrication. However, the high operating voltage of tunable liquid crystal lens has been a significant technical barrier to practical applications and commercialization. In this paper, we propose a tunable liquid crystal lens with raised trapezoidal  
        关键词：tunable lens;liquid crystal lens;electrode structure;operating voltage   
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        发布时间：2020-07-06
      • Ji-yu WAN,He FENG,Dong WANG,Si-kai ZHANG,Tong-Hua YANG,Nan CHEN,Yong-zhi SONG,Sheng-xuan LI,Liang ZHANG,Xi-bin SHAO
        Vol. 33, Issue 1, Pages: 38-42(2018) DOI: 10.3788/YJYXS20183301.0038
        摘要：The mechanism of side-view reddish in LCD is analyzed by the qualitative and quantitative side in this paper. The qualitative result shows that the main factors which influence the side-view reddish areRth and pigment particle distribution of the material. In the quantitative analysis, the theoretical formula which can simulate the level of side-view reddish is obtained by analyzing Rth, thickness of the film, angle between upper polarizer's polarization direction and main observation direction (A-UPMO) and the main wavelength of the transmitted light. According to the above conclusions, side-view reddish can be improved effectively by reducing Rth, thinning film thickness and reducing the A-UPMO. In general, the threshold of Rth for Red/Green/Blue material each is 6.0 nm/5.4 nm/4.0 nm. The research will give guiding theory for new material development and issue improvement in the future.  
        关键词：side view;Rth;LCD;optical analysis   
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        发布时间：2020-07-06
      • Jian SUN,Ruo-chen LAN,Lan-ying ZHANG,Zhou YANG,Huai YANG
        Vol. 33, Issue 1, Pages: 43-48(2018) DOI: 10.3788/YJYXS20183301.0043
        摘要：In order to realize light-driven dynamic alignment of liquid crystal (LC) molecules, photo-responsive cholesteric liquid crystalline composite was prepared by doping chiral overcrowded alkenes into achiral LC hosts. The variation of helical pitch and the dynamic homogeneous alignment of LC molecules in photo-responsive cholesteric liquid crystals (ChLCs) were investigated upon UV exposure with different intensities. The dynamic reconfiguration from focal conic to planar state was demonstrated based on the UV-intensity addressability of the helical pitch. The response time for dynamic homogeneous alignment of planar state can be accelerated from 600 s to 60 s with the increase of UV intensity, whereas the random alignment of focal conic state was developed in the absence of high-power UV exposure due to the sharp fluctuation of helical pitch. To properly modulate the intensity of UV light in multi-procedure protocols, the dynamic alignment technology with rapid response and stable homogeneousness was achieved.  
        关键词：cholesteric liquid crystals;chiral overcrowded alkenes;light-driven;dynamic alignment behavior   
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        发布时间：2020-07-06
      • Xiao-bo KONG,Li-juan LIU,Yong-gang LIU,Li XUAN
        Vol. 33, Issue 1, Pages: 49-54(2018) DOI: 10.3788/YJYXS20183301.0049
        摘要：A tunable dual-wavelength organic laser based on a holographic polymer dispersed liquid crystal (HPDLC) grating was reported, and the dual-wavelength laser performance under an electric field was also investigated. The gain medium of the dual-wavelength organic laser was dye 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) and organic semiconducting poly(2-methoxy-5-(20-ethyl-hexyloxy)-pphenylenevinylene (MEH-PPV), the cavity was HPDLC grating. The laser wavelength could be modulated b  
        关键词：dual-wavelength;organic laser;holographic polymer dispersed liquid crystal grating;electrical tuning   
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        发布时间：2020-07-06

        Driving and Controlling

      • Na-na TANG,Xi-feng ZHENG,Jin-zhong WU,Hao CHEN,Hong-xia LI
        Vol. 33, Issue 1, Pages: 55-60(2018) DOI: 10.3788/YJYXS20183301.0055
        摘要：On the market, the off-line LED display currently used to control the display content mainly by wired. With the rapid development of mobile communication technology, 4G is beginning to enter the popular stage. Compared with the traditional wired communication mode, 4G technology isn't bound by the place and has obvious advantages in engineering cost, environment adaptability, network expansion, equipment maintenance and so on. In order to solve the problem that wired LED display is not installed because of   
        关键词：4G-LTE;ARM;FPGA;I.MX6Q;LED off-line screen   
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        发布时间：2020-07-06
      • Tao CHEN,Jin-yu ZHAO,Jian-lu JIA
        Vol. 33, Issue 1, Pages: 61-66(2018) DOI: 10.3788/YJYXS20183301.0061
        摘要：In order to simplify the system for camera testing and reduce the cost, an USB3.0 interface based on FT600 of FTDI Company is designed. First, a brief introduction of the complexity for testing the camera with Camera link interface and the advantage for using USB3.0 interface is presented. Then an explanation for circuit design of the interface is showed, and according to the datasheet, the circuit design of the FT600 and the FPGA is accomplished. Finally, the FPGA is programmed by using the Verilog HDL and the USB3.0 interface is tested by using the software provided by the FTDI. Experimental results indicate that the work mode of the USB3.0 interface can be configured according to software, and the interface can transfer the data at 200 Mbyte/s. It can satisfy the camera test requirements and simplify the system for testing.  
        关键词：USB3.0;FPGA;FT600   
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        发布时间：2020-07-06
      • Tao YU,Xin FANG,Xian-chao XUN
        Vol. 33, Issue 1, Pages: 67-73(2018) DOI: 10.3788/YJYXS20183301.0067
        摘要：In order to ensure that the lunar based extreme ultraviolet camera can finish the engineering task satisfactorily, monitor and research the earth plasmasphere, the software system was designed and implemented. Firstly, the structure and the operating principle of software system were introduced. Then, the key modules and work mode of software system were designed in detail. Finally, the long-term exploration results of extreme ultraviolet camera based on lunar were analyzed in detail. The exploration result  
        关键词：extreme ultraviolet camera;software system;plasmasphere   
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        发布时间：2020-07-06

        Display Technology

      • Ji-jun LI,Xiao-meng NIE,Wei ZHEN,Yun-gang DU
        Vol. 33, Issue 1, Pages: 74-84(2018) DOI: 10.3788/YJYXS20183301.0074
        摘要：The structure and principle of liquid crystal display (LCD), Organic Light Emitting Diode (OLED) display, Quantum Dot Light Emitting Diodes (QLED) display and laser display are analyzed. The structure, material, performance and application fields about these display technologies are compared. The new developments of these display technologies are given. Due to the mature technology and low cost, LCD display still plays an important role in the display industry. Due to the advantages of fast response, lightw  
        关键词：display technique;liquid crystal display;organic light emitting diode display;quantum light emitting diode display;laser display   
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        发布时间：2020-07-06

        Image Processing

      • Ze-wei WANG,You-guang YU,Fu-zheng YANG
        Vol. 33, Issue 1, Pages: 85-91(2018) DOI: 10.3788/YJYXS20183301.0085
        摘要：In recent years, "virtual reality" has been more and more popular and brought with it an unprecedented fantastic user experience. Panorama video, as one of the main construction ways of virtual reality, on account of its good user experience and human-computer interaction ability, has been widely used in many fields, such as medical, entertainment, education and industrial design. With the increasing demands for good user experience, how to ensure the user experience of panorama video in various application  
        关键词：virtual reality;panoramic video;display system;visual experience;quality assessment   
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      • Min WANG,Xin-yuan SHI,Zhi-hui WANG,Ze-yang LI
        Vol. 33, Issue 1, Pages: 92-98(2018) DOI: 10.3788/YJYXS20183301.0092
        摘要：Aiming at the problem that the space-time context algorithm is prone to drift and can not retrieve the target after target tracking is lost, a moving gesture tracking algorithm combining Vibe foreground detection and space-time context is proposed. Firstly, the space-time context algorithm is used to estimate the gesture and detect the interference. When the interference is detected, the Vibe algorithm is used to calibrate the estimated results of the space-time context algorithm and update the target model. The advantage of this method is that the Vibe algorithm with no parameter model is used to calibrate the whole process of gesture tracking. The experiment adopts overlap success rate and center location errors as the evaluation system. The experimental results show that the improved algorithm is 60% higher than the original algorithm in tracking success rate. This method enhances the motion gesture tracking effect and improves the robustness of the space-time context algorithm.  
        关键词：space-time context;Vibe;gesture tracking;interference detection;robustness   
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