Contrast improvements for scrolling‐color LCoS

Abstract— A scrolling‐color LCoS (liquid‐crystal‐on‐silicon) display must exhibit both fast speed and high contrast. These requirements drive design choices for the liquid crystal and optics of the image kernel. The input director was aligned to the incoming polarization and a compensated 45TN0 effect was choosen. Contrast demands place tight requirements on interfacial reflections. A wire‐grid PBS can achieve high contrast and can simplify the system construction. With attention to the above, we report a sequential contrast of 800:1 at the viewing screen. With a 90TN0 effect, the contrast can be increased even further, but with some penalty in light efficiency. With this effect, sequential contrast of 2000:1 was measured.     

General methodology for LCoS panel compensation

Abstract— A general three‐step methodology is presented to optimize contrast when compensating LCoS panels. The first step acts to compensate the in‐plane residual retardation, while the second one improves the field of view (FOV) using either MacNeille‐type or wire‐grid polarizing beamsplitters (PBS). The orientation of the LCoS panel and compensator, relative to the MacNeille PBS, are very critical to achieve good system contrast. The final step is to account for reflections from anisotropic material, which appear as on‐state light, limiting contrast.     

Front‐projection optical‐system design for reflective LCoS technology

Abstract— Optical designs for three‐panel LCoS projection systems are reviewed. The impact of polarization aberrations in prism‐based systems is discussed and a simple model to analyze the sensitivity of contrast to thermal gradients in prisms is presented. To eliminate stress birefringence in LCoS projection systems, we have developed a projection optical system that does not require the use of polarizing prisms. An improved off‐axis design has been designed that simplifies manufacture and reduces cost. The performance of systems based on this architecture will be discussed.     

Measurement methods for LCoS displays

Abstract— Two measurement methods to characterize uniformity and the absolute cell gap of LCoS images will be reviewed. These are simple to use in a production environment and have allowed major improvements in manufacture to be achieved. For the purpose of this paper, the liquid‐crystal mode used is the 45° normally black mode.     

3D digital cinema technologies

We describe fundamental aspects of the two major digital cinema projector platforms with special regard to the needs of 3D cinema. We present several optical solutions for 3D digital cinema, including polarization‐converting modulators, over‐under lenses, and dual projector systems. Finally, we define a metric for 3D efficiency and compare several solutions on this basis.     

Invited Paper: Super Hi‐Vision projection display for next‐generation TV

Abstract— For future broadcasting, NHK is studying new video services offering very‐high‐picture quality achieved through Super Hi‐Vision. Toward that aim, a projection display that has a resolution equivalent to 7680 × 4320 pixels by using four 4096 × 2160 D‐ILA? panels has been developed. The display requires precise convergence adjustment because it consists of two projection units, so an automatic adjustment system was developed. Although the pixel number of the digital camera used is less than that of the display, a 0.2‐pixel accuracy was obtained. This report introduces theaters that use this display as an example of applying the Super Hi‐Vision video system.     

A submillisecond‐response liquid crystal for color sequential projection displays

We report a new LC with low viscosity and high clearing point (T_c ~102 °C) for color‐sequential projection displays. Using a 1.95‐µm mixed‐mode twisted nematic cell, the averaged gray‐to‐gray response time is less than 1 ms, which is ~3.6× faster than the current state of the art. Such a mixed‐mode twisted nematic liquid‐crystal‐on‐silicon can be used for near‐to‐eye wearable projection displays and head‐up displays in vehicles.     

Microdisplay‐based optical module for avionic display applications

Abstract— A new optical scheme for a LCOS‐based rear‐projection system utilizing an LED illumination source is presented. The proposed optical module could conveniently replace conventional aircraft panel instrumentation not only because it achieves major standard avionics application requirements, such as the capability to withstand mechanical shocks, high reliability, and weight and power‐consumption minimization, but also as a consequence of the fact that it allows the display image area to be properly matched to the shape of the instrument panel more easily than with conventional displays.     

LCDs for TV applications

Abstract— Super IPS (S‐IPS) technology has intrinsic advantages in several aspects required for TV applications. Particularly, the wide‐viewing‐angle property and fast gray‐to‐gray response time of S‐IPS LCDs are both necessary requirements for family and individual use for LCD TVs. Given these benefits and other advantages S‐IPS provides, LG.Philips LCD has developed high‐performance S‐IPS LCDs for TV, which have now become competitive with plasma‐display panels (PDPs), in addition to other modes of LCD TVs as well as CRTs. This article will discuss why S‐IPS technology is the leading choice for LCD‐TV applications.     

数字式2D比例换向阀控制器的研究

为使所开发的2D比例换向阀达到较好的性能,设计一款基于DSP芯片的数字式比例控制器,将高频PWM波作用于反接卸荷式H桥驱动电路以控制线圈电流变化,并且内置PID模块实现电流闭环控制。同时,在PID模块增加线性回归算法对线圈电流进行校正。为了减小2D比例换向自身的摩擦力,内置颤振模块,可实现颤振幅值和频率的独立调节。实验结果表明,该控制器具有良好的稳态控制性能,由其控制的比例阀性能得到极大提高。     

Metadata requirements for digital museum environments

We describe a system which addresses all the processes involved in digitally acquiring, modelling, storing, manipulating and creating virtual exhibitions from 3D museum artefacts. More specifically, we examine the significance of metadata in enabling and supporting all of these processes and describe the extensive facilities provided for authoring, maintaining and managing metadata. The development of the system has been heavily influenced by factors relating to interoperability, standards, museum best practice and feedback from two museum pilot sites. Finally, we briefly consider the system in the wider context of applications such as virtual learning environments and distributed repositories of archives.     

Design and implementation of readout circuit on glass substrate with digital correction for touch‐panel applications

Abstract— A readout circuit on glass substrate with digital correction, which contains a transconductance amplifier, counter, and digital correction circuit, has been designed for touch‐panel applications for 3‐μm low‐temperature polysilicon (LTPS) technology. The voltage difference as a result of a change in capacitance due to a touch event is converted to current by a transconductance amplifier. By charging and discharging the capacitor in the counter, the counter displays different digital‐output codes according to touch or non‐touch events. Furthermore, not only can the touch or non‐touch event be distinguished, but also the influence of LTPS process variation can be compensated by a digital correction circuit in the proposed readout circuit.     

Specifying comfortable driving postures for ergonomic design and evaluation of the driver workspace using digital human models

Specifying comfortable driving postures is essential for ergonomic design and evaluation of a driver workspace. The present study sought to enhance and expand upon several existing recommendations for such postures. Participants (n = 38) were involved in six driving sessions that differed by vehicle class (sedan and SUV), driving venue (laboratory-based and field) or seat (from vehicles ranked high and low by vehicle comfort). Sixteen joint angles were measured in preferred postures to more completely describe driving postures, as were corresponding perceptual responses. Driving postures were found to be bilaterally asymmetric and distinct between vehicle classes, venues, age groups and gender. A subset of preferred postural ranges was identified using a filtering mechanism that ensured desired levels of perceptual responses. Accurate ranges of joint angles for comfortable driving postures, and careful consideration of vehicle and driver factors, will facilitate ergonomic design and evaluation of a driver workspace, particularly when embedded in digital human models.     

Clinical applications for stereoscopic 3‐D displays

Abstract— Stereoscopic 3‐D digital imaging holds the promise of improving the detection, diagnosis, and treatment of disease as well as enhancing the training and preparation of medical professionals through use of stereoscopic 3‐D displays in concert with the many volumetric visualization techniques/modalities developed in recent years. While so‐called 3‐D graphics have improved the state of computer visualization in general, 3‐D displays make full use of the human‐visual perception, and thus can provide critical insight in complex computer‐generated and video 3‐D data. The stereo 3‐D applications reviewed in this paper include screening of breast cancer and diabetic retinopathy, visualization for minimally invasive surgery, and the teaching of anatomy. Also included is a discussion of ground‐breaking results from a stereo digital mammography clinical trial under way at Emory University.     

A digital predistorter for wireless transmitters

A novel digital baseband predistorter with improved reduction of spectral regrowth is proposed and investigated. The improvements are achieved by using a proposed predistortion technique and extended power amplifier (PA) fundamental‐frequency modeling. The digital baseband predistortion (DPD), known for its simplicity of realization, low cost and integrability; however, it suffers from poor linearizing performances. We incorporate baseband iterative injection of in‐band distortion components into the baseband DPD to enhance the nonlinearity compensation. General formulas for the fundamental‐frequency output of a PA with n‐order nonlinearity and recursive formulas for calculating the injected components for different number of iterations are developed. The proposed iterative digital baseband predistorter is verified experimentally with a wireless PA and measured results are presented to demonstrate feasibility of the proposed concept. The spectral regrowth suppression of 20 dB is achieved for a 3.5 MHz digitally modulated signal. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

A super‐fine‐pitch screen for rear‐projection TV

Abstract— An advanced screen for use with LCD/LCoS/DMD rear‐projection TV has been developed. A lenticular lens having a pitch of 64 μm has been developed without loss in any other optical property. A 70% black‐stripe ratio was obtained by optimizing the patterning process, which maintains high contrast. As described in this paper, the FC‐Screen manufacturing technology has been further developed.     

组合结构设计的双频带数字预失真方法

双频带射频功放的数字预失真技术(DPD)要求支持更宽的带宽.为了保证功放输出的线性指标并降低预失真系统的实现开销,设计一种组合结构的双频带宽带数字预失真方法.该方法采用一维整频带数字预失真模型与四个一维分频带数字预失真模型的组合结构来综合处理双频带的发射信号.仿真实验结果表明,采用90 MHz的双频带LTE信号,临道泄露比(ACLR)指标较改进的二维记忆多项式DPD有1 dB提升,与二维DPD有0.5 dB差别,满足系统指标要求.     

Invited Paper: UHP‐lamp systems for projection applications

Abstract— Projection systems have found widespread use in conference rooms and other professional applications during the last decade and are now entering the home‐TV market with considerable pace. Projectors as small as about one liter are nowadays able to deliver a screen flux of several thousand lumens and are, with a system efficacy of more than 10 lm/W, the most‐efficient display system realized today. Because such highly efficient projectors employ microdisplays as light valves, short‐arc lamps are a key component in realizing these properties. The introduction of the UHP‐lamp system by Philips in 1995 can be identified as one of the key enablers for the commercial success of projection systems. The ultra‐high‐performance (UHP) lamp concept features outstanding arc luminance, a well‐suited spectrum, long life, and excellent flux maintenance. For the first time, it combines a very‐high‐pressure mercury‐discharge lamp having an extremely short and stable arc length with a regenerative chemical cycle that keeps the discharge walls free from blackening, leading to lifetimes of over 10,000 hours. In this review, the most important aspects of the UHP concept that enabled its success in the projection market are described, followed by a discussion of some recent additions to the UHP‐product portfolio.     

Cermet cathodes: A new technology for CRT applications

Abstract— In this paper, we present results for a new type of cermet cathode (Oxide Plus) in a range of CRT tube types including wide‐screen 32‐in. and 34‐in. tubes together with 19‐in. computer‐monitor tubes. The results indicate that the cermet cathode exhibits good performance in all types of tube where previously oxide cathodes were not suitable and only Ba‐dispnser cathodes could be used. We also illustrate a new suspended cathode structure compatible with RCA‐type cathodes that could enable a wider adoption of this new technology.     

施工总布置三维可视化数字模型研究

为直观准确地描述施工总布置中各施工环节之间复杂的变化时空关系,以水利水电工程为基础,借助GIS特有的空间数据组织结构和可视化表达功能,构造了施工总布置三维可视化数字模型,其中包括施工场地地表三维数字模型(DTM)和施工总布置建筑物实体三维数字模型,并根据需要对地形数字模型进行了填挖处理。在此模型基础上实现了施工过程的三维动态演示、三维场景沿河流巡航、施工总布置可视化信息查询和局部观察。工程实际中的应用表明该模型可为工程施工组织设计提供一个科学有效的可视化分析和辅助决策手段。