电润湿显示系统的电光响应机理及特性

针对电润湿显示器像素内流体运动机理及相应电光响应特性,提出一种数值模拟计算方法来计算电润湿中流体间的界面变化及流体-液体-固体三相接触线在外部电场影响下的运动。该方法基于Matlab数值分析框架,通过Young-Laplace方程计算界面形状变化及变化过程中三相接触角、界面接触面积等参数的变化,并结合总体能量守恒方程求解像素的电光响应过程。实验结果表明,该模型成功模拟电润湿显示器像素内电流体动力特性,像素响应时间与油-水界面张力大小成正比。模拟结果与相同参考几何的实验数据具有良好的定性一致性,可用来指导电润湿器件中流体参数的设计,对实现高稳定的电润湿显示器具有重要意义。

铁电液晶显示器单像素电光响应特性测量系统

采用自行设计的测量系统对自制的１２８ ×１２８ 铁电液晶显示器不同区域像素的电光响应特性进行了测量，这些测量结果对铁电液晶器件的制作有一定的参考价值。

ZnTe晶体对太赫兹波的电光响应及极化匹配

给出了ZnTe电光晶体折射率和吸收系数随太赫兹波频率而变化的计算曲线,比较了太赫兹波在ZnTe中传播时的相速度和群速度。通过与太赫兹频率和晶体厚度相关的电光效率响应函数,理论计算了ZnTe电光晶体对太赫兹脉冲的探测电光响应,得到了晶体厚度与探测到的太赫兹频谱宽度的定性关系,从计算结果中找到了ZnTe电光晶体在5.3 THz和6.2 THz等多个频点的探测盲点,这些探测盲点来自于ZnTe电光晶体与相应频点太赫兹波的栅格共振吸收。结合自制的大口径太赫兹光导天线和1 kHz脉冲重复频率的太赫兹时域光谱实验系统,通过差分探测技术,从实验上得到了太赫兹波极化方向与〈110〉型ZnTe晶体晶轴方向的六个最佳匹配角度,给出了太赫兹电场最大值随晶轴与太赫兹波极化方向之间夹角变化的曲线及经验公式,这将有利于在实践中对该现象的深入理解和对探测灵敏度的有效提高。

弹性形变对手征液晶螺旋光轴及电光响应时间的影响

手征向列相液晶螺旋轴即为光轴,此轴的空间取向直接影响着液晶中光传播的特性。采用理论分析和数值模拟相结合的方法,研究了液晶展曲与弯曲形变存在的差异和对手征向列相液晶挠曲电螺旋光轴倾角及动力学响应特性的影响。假设在静电平衡及动力学响应两种状态下,系统均具有统一的挠曲电螺旋光轴,忽略介电各向异性,分别计算了两种不同状态下系统的平均自由能密度。利用欧拉方程及转矩平衡方程得到了螺旋光轴倾角满足的平衡方程及动力学方程。通过数值计算,讨论了两种形变的差异对挠曲电螺旋光轴倾角及动力学响应特性的影响。结果表明两种形变差异的存在,均使螺旋光轴扭曲角及特性响应时间变化,差异越大变化越快,这种影响是不可忽略的,这为液晶电光快速响应提供了依据。

液晶复合材料的电光特性

基于液晶复合材料中液晶微粒的电控光散射原理，对这种新材料的光散射和电光响应进行了初步理论和实验研究，研究表明它们具有适于大面积显示、光阀等应用的新型性能。

液晶显示器件电光特性实验设计

对电子科技大学液晶显示技术实验的教学改革进行了探讨。通过实验系统功能的扩展,利用一激光照射液晶屏,再通过一激光探测器进行测试,可测试液晶像素的视角特性和电光响应曲线,强化了学生综合能力的训练。

环氧基PDLC的制备及其电光性质

PDLC是一种新型的固态显示器件,具有优良的光电响应性能。我们以环氧交联法制备PDLC膜,考察了不同固化条件、浓度配比对PDLC膜形态结构的影响,讨论了凝胶点和分相机理的关系,进而测量了PDLC膜的光电响应,并对其响应过程提出了新的看法。

反射式扭曲向列相液晶显示器工作模式的演化

用动态参数空间方法研究了反射式扭曲向列相液晶显示的常白工作方式， 观察到， 当偏振片角度β变化时， 显示从纯电控双折射（ECB）模式演化到反射式扭曲向列相模式（扭曲角为52°）。 并且第一和第二ECB模式虽沿着不同路径演化， 但最终合并成同一个优化反射式扭曲向列相模式。 从反射式扭曲向列液晶显示模式的演化角度出发， 研究了电光响应、 反射率对波长的依赖关系等。

LCD Gamma校正的硬件实现

通过对液晶(LC)S型电光响应曲线的研究,设计了一种由非线性DAC来实现LCD G amm a校正过程。由模拟退火算法获得了C-DAC中7个关键电容参数值,用设计出bu ffer来提高DAC驱动负载的能力,并通过直接译码电路,巧妙地解决了显示输出对比度的问题,经过对M atlab和H sp ice仿真,证明可以实现LCD G amm a校正的功能,解决了显示图像精确逼近原始图像的问题。

Stable zinc oxide field emitter-based backlight unit for liquid crystal display

A zinc oxide ZnO field emitter-based backlight unit for liquid crystal display with a gated structure is fabricated by screen-printing processes.The measured anode field emission current density reaches 0.62 mA/cm2 when the applied gate voltage is 570 V.Part of the anode current is contributed by the secondary electron emission which is excited from the MgO layer inside the gate apertures on the gate plate. The average emission current density and luminance are 0.47 mA/cm2 and 1 250 cd/m2 respectively with a fluctuation of about 10% during the 1 000 min measurement.By a finite element method calculation the gated structure shows a good electron beam focusing property. The driving performance of the backlight unit is characterized by SPICE simulation tools and measured by the oscilloscope. Stable field emission line-by-line scanning and fast response characteristics of the backlight unit indicate its promising application in the liquid crystal displays.

Numerical Simulation and Analysis of Bipolar Junction Photogate Transistor for CMOS Image Sensor

A new photodetector--bipolar junction photogate transistor is presented for CMOS image sensor and its analytical model is also established.With the technical parameter of the 0.6μm CMOS process,the bipolar junction photogate transistor is analyzed and simulated.The simulated results illustrate that the bipolar junction photogate transistor has the similar characteristics of the traditional photogate transistor.The photocurrent density of the bipolar junction photogate transistor increases exponentially with the incidence light power due to introducing the injection p+n junction.Its characteristic of blue response is rather improved compared to the traditional photogate transistor that benefits to increase the color photograph made up of the red,the green,and the blue.

电光可调谐有限脉冲响应滤波器设计

为得到高矩形度、低旁瓣、电光调谐逆向可导及通带带宽可调的电光可调谐滤波器,在x切y传的钛扩散铌酸锂(Ti∶LiNbO3)波导上,对周期性分布的N级叉指电极组提供分立电压V,产生周期性电场,实现似TE模与似TM模的偏振转换,进而实现滤波功能。该结构构成有限脉冲响应(FIR)网络,网络传输矩阵H(z)与电压V具有一一对应关系。利用z变换原理,运用待定系数法求解H(z),从而推导所需电压值V,实现了电光调谐逆向可导。加入不同电压,可以实现自由光谱范围(FSR)内不同通带宽度的可调谐滤波特性。通过仿真验证,该算法是可行的。当N为17时,边模抑制比(SMSR)可达到25dB。并且滤波曲线的矩形度随着叉指电极组级联级数N的增大而增大。

Optical Rectification Induced by Al-Si Schottky Barrier Potential and Mechanism of Two-Photon Response

By observing two-photon response and anisotropy of the light-induced voltage in Al-Si Schottky barrier potential,it is certified from the experimental and theoretical analysis that the built-in electric field generated by the Schottky barrier potential will induce the phenomena of optical rectification in Si photodiode.Thus,it is deduced that there must be double-frequency absorption caused by phase-mismatch in the mechanism of two-photon response of Si photodiode.If the intensity of the built-in electric field is strong enough,the double-frequency absorption will be the main factor of the two-photon response,which is different from the conventional opinion that the two-photon response is just the two-photon absorption.

Facile fabrication of ZnIn2S4/SnS2 3D heterostructure for efficient visible-light photocatalytic reduction of Cr（Ⅵ）

Photocatalytic method has been intensively explored for Cr(VI)reduction owing to its efficient and environmentally friendly natures.In order to obtain a high efficiency in practical application,efficient photocatalysts need to be developed.Here,ZnIn2S4/SnS2 with a three-dimensional(3D)heterostructure was prepared by a hydrothermal method and its photocatalytic performance in Cr(VI)reduction was investigated.When the mass ratio of SnS2 to ZnIn2S4 is 1:10,the ZnIn2S4/SnS2 composite exhibits the highest photocatalytic activity with 100%efficiency for Cr(VI)(50 mg/L)reduction within 70 min under visible-light irradiation,which is much higher than those of pure ZnIn2S4 and SnS2.The enhanced charge separation and the light absorption have been confirmed from the photoluminescence and UV-vis absorption spectra to be the two reasons for the increased activity towards photocatalytic Cr(VI)reduction.In addition,after three cycles of testing,no obvious degradation is observed with the 3D heterostructured ZnIn2S4/SnS2,which maintains a good photocatalytic stability.

Numerical Simulation of Spectral Response for 650 nm Silicon Photodetector

The theoretical spectral response formula of the N+-N-I-P+ silicon photodetector with high/low emission junction is given. At the same time, considering the process requirements, the optimum structure parameters of silicon photodetector are obtained by numerical calculation and simulation. Under the condition of these optimum structure parameters, the responsivity of the silicon photodetector will be 0.48 A/W at 650 nm.

Fabrication of PdSe2/GaAs Heterojunction for Sensitive Near-Infrared Photovoltaic Detector and Image Sensor Application

In this study,we have developed a high-sensitivity,near-infrared photodetector based on PdSe2/GaAs heterojunction,which was made by transferring a multilayered PdSe2 film onto a planar GaAs.The as-fabricated PdSe2/GaAs heterojunction device exhibited obvious photovoltaic behavior to 808 nm illumination,indicating that the near-infrared photodetector can be used as a self-driven device without external power supply.Further device analysis showed that the hybrid heterojunction exhibited a high on/off ratio of 1.16×10^5 measured at 808 nm under zero bias voltage.The responsivity and specific detectivity of photodetector were estimated to be 171.34 mA/W and 2.36×10^11 Jones,respectively.Moreover,the device showed excellent stability and reliable repeatability.After 2 months,the photoelectric characteristics of the near-infrared photodetector hardly degrade in air,attributable to the good stability of the PdSe2.Finally,the PdSe2/GaAs-based heterojunction device can also function as a near-infrared light sensor.

Three Dimensional Study of Spectral Response of Polycrystalline Silicon Solar Cells： Vertical Junction Frequency Modulation Scheme

In this paper, the modeling ofa bifacial polycrystalline silicon solar cells vertical junction is presented. The study in dynamic frequency is limited to wavelengths from 400 nm to 1100 nm. The dependence of solar cell spectral response on wavelengths for several modulation frequencies was evaluated by using solar cell internal quantum efficiency.The objective is to characterize the polycrystalline silicon in 3D. The effect of frequency modulation pulsation on the phase of internal quantum efficiency was presented as well as values of shunt and series resistance for various grains size values. The results show that the value of maximum internal quantum efficiency is about 50% with a wavelength of 0,82 nm and a frequency of 103 rad/s under monochromatic illumination.

A Study on Modelling Surface Finish in Electrical Discharge Machining Tablet Shape Punches Using Response Surface Methodology

This paper introduces a study on modelling surface finish in EDM （Electrical Discharge Machining） of tablet shape punches when using copper as electrode material. In this study, 27 experiments were performed based on BBD （Box-Behnken Design） and the work-piece material was 9CrSi steel. The input process parameters were the current, the pulse on time, the pulse off time and the voltage. The effects of the input parameters on the surface finish were evaluated by analysing variance. Besides, from the results of the experiments, a regression equation for determining the surface roughness is introduced. Also, the optimum input parameter values were found in order to get the minimum surface roughness.

Nonlinear Optical Response of Conjugated Polymer to Elec tric Field

The organic π-conjugate d polymers are of major interest materials for the use in electro-optical and no nlinear optical devices. In this work, for a selected polyacetylene chain, the optical absorption spectra in UV/Vis regime as well as the linear polarizabiliti y and nonlinear hyperpolarizability are calculated by using quantum chemical ab initio and semiempirical methods. The relationship of its optical property to el ectric field is obtained. Some physical mechanism of electric field effect on mo lecular optical property is discussed by means of electron distribution and intr amolecular charge transfer.