反射型LCOS器件用于红外场景仿真研究

提出采用反射型LCOS（Reflective Liquid Crystal on Silicon-RLCOS）器件实现动态红外场景仿真,阐述了RLCOS器件的结构及信号写入原理。利用液晶指向矢分布计算模型和光在液晶中传播规律计算模型,分析了液晶光阀的电光特性,结果表明,如果选取一组适当的光阀参数,可使光阀在中波和长波红外波段均有较好的调制特性,输出红外辐射功率与像素电压有较近似的线性关系,可以达到较好的仿真效果。     

液晶光阀的双稳态特性研究

测量了TB3639型液晶光阀在电压驱动下的光谱特性及其光学双稳态特性,并讨论其产生光学双稳态特性的非线性效应物理机制,分析了液晶光阀的光学双稳态特性不明显的原因.分析结果表明,扭曲角对液晶光阀的光学双稳态特性影响较大,由于TN型液晶光阀的扭曲角只有90°,导致其双稳态特性不是很明显,TB3639型液晶光阀在某一电压范围内存在光学双稳态特性.     

7×7电寻址红外液晶光阀

采用光寻址红外液晶光阀的动态红外场景生成系统受可见光图像写入源的影响,输出的红外图像帧频较低(＜100Hz),而且光寻址液晶器件结构相对复杂,能量利用率低.针对这些缺点,提出了一种采用预应力液晶的电寻址红外液晶光阀以7×7阵列的反射式电寻址红外液晶光阀为例,介绍了电寻址红外液晶器件的结构及制作过程,设计了采用逐点扫描的驱动控制电路,得到了具有灰度的红外图形.这种电寻址红外液晶光阀结构紧凑简单,能量利用率高,输出图像的帧频可达250 Hz,为研制具有实用价值的高分辨率、高帧频的电寻址红外液晶光阀提供了技术基础.     

利用无定形硅光敏元件和铁电液晶的高速光阀

本文首次介绍了一种新的高速响应光阀,它由氢化无定形硅(α-Si:H)光敏元件和手性层列C相液晶构成。这种器件以光学方式寻址,通断状态之间的开关是让液晶两端的外加电压(也即α-Si:H光敏元件的光电流)极性反向得到的。测得的响应时间约为400μs。这种器件的开关速度比向列液晶光阀的速度快1—2个数量级。使用铁电液晶的电光记忆效应,可以把该器件应用于没有光学反馈的光学双稳态器件。     

相位型图像实时可调假彩色编码

相位型图像经滤波后写入液晶光阀,用白光读出,可以实现相位型图像实时可调假彩色编码。采用液晶光阀的简化混合场效应模式,论述了这种编码方法的原理。给出了典型的假彩色编码结果。     

反射式相变宾主型显示器

详细介绍了反射式相变宾主型液晶显示器的工作原理、器件特性及它所存在的缺点，并介绍了最新研究进展。     

红外液晶光阀参数设计及电光特性分析

利用液晶指向矢分布计算模型和光在液晶中传播规律计算模型,优化设计了液晶光阀参数。对E7液晶材料,选取沿面平行排列方式、5～10°预倾角、液晶层厚度10 μm作为液晶光阀参数,模拟计算了该液晶光阀的电光特性。测试了红外液晶光阀的红外输出光谱和输入灰度与等效温度的变化关系,结果表明,该液晶光阀的光谱输出特性和光学调制特性有益于红外场景仿真。     

MIS型单晶硅液晶光阀

详细介绍了一种新颖、快速响应的金属－绝缘层－半导体构成的MIS型单晶硅液晶光阀的结构、工作机理、制作工艺和性能参数测试。液晶采用45°扭曲向列型混合场效应工作模式。所得到的光阀的极限分辨率为40lp／mm，口径40mm，最大对比度＞100：1，在930nm（△λ＝40nm）写入光灵敏度为20μW／cm2，响应时间为15ms。报道了该光阀在大屏幕投影显示中的应用。     

切变聚合物网络液晶光阀

针对向列型液晶光阀响应速度慢的问题,提出了一种工作在可见光波段的切变聚合物网络液晶光阀(SLCLV).通过测定其电光响应,这种切变聚合物网络液晶(SLC)的响应时间可达几个毫秒,比相同条件下的向列型液晶的响应速度提高了一个数量级,而且对厚度依赖性小.通过理论分析,提出了SLC的工作原理,介绍了工作在可见光波段的反射式电寻址SLCLV的制作过程.器件的制作工艺简单,可靠性高.在可见光-可见光图像转换系统中,测得这种液晶光阀的帧频可达500 Hz,分辨率为81p/mm.如果能进一步提高制作工艺,这种液晶光阀在高速光学信息处理方面有广阔的应用前景.     

热寻址近晶相液晶光阀显示

一种利用近晶相液晶光阀的高分辨率、高对比度的激光寻址显示技术已经研制成功,它是用一束有选择地扫描受热液晶光阀寻址。液晶光阀是由能吸收激光束的液晶盒和夹在透明电极之间的近晶相型液晶组成。我们通过改变扫描的激光功率,扫描速度,光阀书写电压及光阀所处的温度场,成功地进行了激光束的书写和擦除。     

低功耗LCD

本文评述了各种低功耗反射型 LCD的结构和模式 ,重点讨论了 GH- LCD模式。本文也讨论了它们的发展趋势和关键技术。     

3D channel modeling and space-time correlation analysis for V2V communications

To match complex wireless propagation scenarios,an improved 3D geometry-based stochastic model was proposed for vehicle to vehicle (V2V) communications channel.The exact relationship between the azimuth angle and elevation angle was taken into account and the corresponding space–time correlation function and space–Doppler power spectral density were derived,and the influence of important factors was analyzed.The observations and conclusions show that correlation characteristics is closely related to distribution of the scatterers and the angle of the antenna array under the non-isotropic scattering environment and is affected by the elevation angle of the antenna array under the isotropic scattering environment.And the space-time correlation characteristics in high vehicular traffic density is significantly lower than that in low vehicular traffic density.The corresponding simulation model is also derived by using a reasonable parameter calculation method.The simulation results validate the rationality of proposed model.It greatly improves analysis and simulation efficiency of V2V MIMO system.     

红外成像导引头角跟踪系统仿真分析

根据红外成像导引头角跟踪系统控制回路各部分的线性化数学模型，建立了导引头的数学模型。对导引头角跟踪回路进行了仿真和分析，从跟踪回路的跟踪性能、参数变化对回路性能的影响、考虑射手模型时角跟踪回路的性能、隔离度测试等方面进行了分析和验证。仿真结果表明，导引头跟踪回路的超调量、上升时间、隔离度等性能已基本满足设计要求，且具有较好的抗干扰能力。对导引头角跟踪系统进一步优化提出了建议，为红外成像导弹制导系统总体方案的确定和总体参数的设计提供了依据。     

微波着陆系统精度技术研究

机动式微波着陆系统(MMLS)克服了固定架设对架设场地要求严格，架设周期长这些限制，使地面设备可以机动架设，但这种机动架设会由于架设场地的原因而使设备天线发生倾侧，引起测量误差。本文拟讨论由于天线倾侧引起机动式微波着陆系统测角误差，并给出误差补偿的方法，建立Simulink仿真模型通过仿真运算加以验证。     

微波着陆系统精度技术研究

机动式微波着陆系统(MMLS)克服了固定架设对架设场地要求严格，架设周期长这些限制，使地面设备可以机动架设，但这种机动架设会由于架设场地的原因而使设备天线发生倾侧，引起测量误差。本文拟讨论由于天线倾侧引起机动式微波着陆系统测角误差，并给出误差补偿的方法，建立Simulink仿真模型通过仿真运算加以验证。     

Feature size limit of liftoff metallization technology

The feature size limits for liftoff metallization technology are evaluated both experimentally and by computer simulation following Blech's model. The mechanism producing a smoothly sloped metallization pattern profile was also clarified. The simulation reveals that the average slope angle of the metallization pattern sidewalls is determined by the reverse mask topology, metallization thickness, and the maximum incident angle of the evaporation system used for the metallization deposition. Simulation results showed good coincidence with experimental results. It is shown that the average slope angle can be controlled between 20° and 70° with polyimide liftoff technology. Feature size limit, i.e., the minimum pitch of metallization patterns, is determined by the reverse mask topology and the maximum incident angle as well as by mechanical and chemical properties of the polyimide layer, but is independent of metallization thickness. In a sample application of the technology in the fabrication of interconnections on rugged LSI surfaces, the minimum pitch of the polyimide liftoff metallization patterns was estimated to be 2.6 µm.     

Robust energy-to-peak sideslip angle estimation with applications to ground vehicles

In this paper, the observer design problem for the sideslip angle of ground vehicles is investigated. The sideslip angle is an important signal for the vehicle lateral stability, which is not measurable by using an affordable physical sensor. Therefore, we aim to estimate the sideslip angle with the yaw rate measurements by employing the vehicle dynamics. The nonlinear lateral dynamics is modeled firstly. As the tyre model is nonlinear and the road adhesive coefficient is subject to a large variation, the nonlinear lateral dynamics is transformed into an uncertain model. Considering the variation of longitudinal velocity, an uncertain linear-parameter-varying (LPV) system is obtained. Based on the LPV model, a gain-scheduling observer is proposed and the observer gain can be determined with off-line computation and on-line computation. The off-line computation includes the calculation of a set of linear matrix inequalities and the on-line computation contains several algebraic operations. The proposed design methodology is applied to a four-wheel-independent-drive electric vehicle in simulation. It infers from different maneuvers that the designed observer has a good performance on estimating the sideslip angle.     

Feature Size Limit of Liftoff Metallization Technology

The feature size limits for liftoff metallization technology are evaluated both experimentally and by computer simulation following Blech's model. The mechanism producing a smoothly sloped metallization pattern profile was also clarified. The simulation reveals that the average slope angle of the metallization pattern sidewalls is determined by the reverse mask topology, metallization thickness, and the maximum incident angle of the evaporation system used for the metallization deposition. Simulation results showed good coincidence with experimental results. It is shown that the average slope angle can be controlled between 20/spl deg/and 70/spl deg/ with polyimide liftoff technology. Feature size limit, i.e., the minimum pitch of metallization patterns, is determined by the reverse mask topology and the maximum incident angle as well as by mechanical and chemical properties of the polyimide layer, but is independent of metallization thickness. In a sample application of the technology in the fabrication of interconnections on rugged LSI surfaces, the minimum pitch of the polyimide liftoff metallization patterns was estirriated to be 2.6 /spl mu/m.     

Modeling, analysis, and simulation of MIMO mobile-to-mobile fading channels

This paper' deals with the modeling, analysis, and simulation of multiple-input multiple-output (MIMO) narrowband fading channels for mobile-to-mobile communications. A stochastic MIMO mobile-to-mobile reference channel model is derived from the geometrical two-ring scattering model under the assumption that both the transmitter and the receiver are surrounded by an infinite number of local scatterers. Using a wave propagation model, the complex channel gains are derived and their statistical properties are studied. General analytical solutions are provided for the three-dimensional (3-D) space-time cross-correlation function (CCF). We show that this function can be expressed as the product of two 2D space-time cross-correlation function (CFs), called the transmit and receive CF. From the non-realizable reference model, a stochastic and a deterministic simulation model are derived using a double sum of complex exponential functions. It is shown how the parameters of the simulation model can be determined for any given distribution of the angle of departure (AOD) and angle of arrival (AOA). In case of isotropic scattering, we present a closed-form solution for the parameter computation problem and illustrate some numerical results concerning the transmit CF. The proposed procedure provides an important framework for designers of future mobile-to-mobile communication systems to verify new transmission concepts employing MIMO techniques under realistic propagation conditions.     

数字太阳敏感器成像建模与仿真

为了仿真太阳光的成像情况,基于标量衍射理论、辐射度学建立了包括光学系统模型和光电转换模型在内的完整的数字太阳敏感器成像模型。该模型适用于视场范围内任意角度入射的太阳光。同时,该模型所包含的从太阳辐射到成像面上像元灰度的能量转换体系完整准确。将太阳辐射作为模型输入进行了数值仿真,并与基于太阳模拟器的地面实验结果进行了对比分析。结果表明,该成像模型能比较准确地模拟太阳光的成像情况。该研究为后续的基于太阳敏感器的太阳光和杂散光成像仿真和对比研究提供了基础。