Switching light with light

The basic characteristics of the light amplifying optical switch (LAOS) are explained. The LAOS, as compared to its electronic counterparts, will substantially reduce the interconnect time between components, chips, PC boards, and machines. The use of the LAOS to implement optical logic circuits with multiple input stages that invert and restore the input signal is discussed. Applications to image and signal processing are examined. Future uses are considered     

非相干单色光和白光散斑照相

许多文献阐述了白光散斑技术的理论和实验,但是散射体本身的性质缺少定量的描述,白光是复色光这一物理特性没有得到足够的重视.本文把散斑看成一系列随机空间频谱的迭加,建立了数学模型.并从单色非相于光散斑入手,把得出的结论再推广到白光散斑.二、非相干单色光散斑成像散斑记录系统见图1(图示为透射式,反射式的讨论相同).用非相干单色光照明散射体,与文献     

LED显示屏光安全与光污染的若干研究

文章首先对LED显示屏的光安全问题进行简要分析,在此基础上对LED显示屏光污染问题的解决途径进行论述,期望该研究能够对LED显示屏光安全问题的消除和光污染的防治有所帮助。     

基于大功率白光LED的可见光通信

该设计是基于STM32的大功率白光LED可见光通信系统,白光从发送到接收传输距离最高可达5 m。可传输频率为300 Hz~8 k Hz的模拟信号及高保真音频,波特率可达1.6 Mb/s,输出信号在示波器上无明显失真。该系统具备双信道通信,两路信道同时均可传输300 Hz~8 k Hz的模拟信号。由从站LCD12864液晶显示当前单信道通信或双信道通信。模拟信号经传输后在示波器上显示无明显失真。模拟信号为8倍采样,音频为6倍采样,采样信号经上拉放大后由12位A/D转换器采样,经过△压缩后由主站通过白光LED发射。接收站通过光电接收管接收信号后经解码、D/A转换,转换为模拟信号,模拟信号经滤波放大后输出至示波器或音频放大器。     

基于可见光系统的杂散光评价方法研究北大核心CSCD

随着光电成像技术日新月异的发展,杂散光干扰现象成为光电系统难以回避的问题。为了更好地表征可见光光学系统杂散光程度,解决现有评价方法——PST算法,无法表征杂散光入射在像面的总能量和能量分布的问题,本文提出一种优化后的等效PSTη计算方法。以一种可见光光学系统为例,通过杂散光仿真软件得到太阳光相对系统光轴各离轴角度的杂散光数据,分别使用原有PST算法和PSTη算法与杂散光辐照度分析图进行对比,结果表明PSTη算法在传统PST计算值一致时,能够更为准确表达杂散光变化趋势,由此可以更好的表征可见光光学系统杂散光分布情况。以PSTη作为评价指标设计了可见光光学系统杂散光抑制措施,验证了PSTη具备指导实际杂散光分析抑制工作的能力。该评价指标也可以推广到其他波段的成像系统中。     

非相干强光干扰可见光成像研究

激光是干扰可见光侦察与告警、跟踪与制导系统的常用技术手段,但存在着频段短、波束窄、瞄准难等问题。非相干强光干扰技术能有效弥补激光干扰技术的不足,针对非相干强光干扰可见光成像系统的理论分析与实验测试问题,分析了非相干强光干扰可见光成像系统的技术机理,研究了基于图像结构相似性的干扰效果分析模型,构建了检测干扰过程并获取测试数据的实验平台,实验测试并定量分析了光源照度、入射方向、等效距离、背景照度和视场大小等参数条件的变化对可见光成像质量、干扰实施前后图像的相似程度、非相干强光干扰效果的影响。结果表明：当入射到探测器表面的非相干强光定向光束照度值满足一定条件后,实施干扰前后的图像结构相似性参数平均结构相似度值减小,干扰后的图像质量下降、失真严重,模糊了图像中的有效信息,呈现出难以识别目标与背景的干扰效果。该研究成果可为非相干强光定向光束干扰可见光侦察系统和电视制导武器提供技术支撑和方法参考。     

Light-controlled light valves

Recent technical approaches to optically addressable, cyclic or erasable, light valves for high resolution projection or direct-view display are reviewed. The general concept of light-valving cathode-ray tubes is first presented for historic and technological perspective. Secondly, photoconductor-controlled devices that incorporate a variety of electrically stimulated optically responsive active elements for light modulation, including ferroelectric ceramics, liquid crystals, electrooptic crystals, and deformable media, are compared for their reported functional characteristics. From the standpoint of performance only, there exist several potentially significant technologies that offer the capabilities of high optical sensitivity and rapid response, high amplification ratios, optical storage, and resolution which are not presently available in light valves addressed by means other than optical.     

Liquid-crystal light valves

Liquid-crystal light valves have been built in which a relatively weak-signal image controls the flow of light to a much brighter projected image. The brightness of the projection light is limited only by heating in the light valve, and so great optical gain is possible. Brightness gains of 10?20 have been achieved with 30?W/cm2 of signal light at an efficiency of 15%. Resolutions of 5 line pairs per mm on the light valve and contrast ratios of 10:1 have been obtained, with a response time of about 0.1 s. With improvements, resolutions of 10?20 line pairs per mm relatively fast response and sensitivity to signal-light levels of nW/cm2 may be expected.     

换上红外线感应灯

终于搬进了我心仪已久的新房,一切都按照我的设想装修完成,可刚住进去没两个星期困扰就出现了,晚上进屋时或者起床上洗手间时间总是要摸半天开关,才能把灯打开。也许你会说,习惯了就有感觉知道开关在那里了,但总是免不了去摸墙。     

Advertising electric light

Electric lighting is so much a part of modern life that it is easy to imagine that everyone wanted it as soon as it became available. That was not the case. In May 1882, Sir William Siemens was questioned by a House of Commons Committee about the electricity supply that his company was then running at Godalming, in Surrey, to the south of London. Siemens had to admit-reluctantly-that after six months operation, only seven or eight people had been persuaded to take an electricity supply in their homes. Even that enthusiastic electrical engineer R. E. B. Crompton, writing in 1888, expected that only one third of households would adopt it. Those who wanted to sell electric lighting needed to be very vigorous and persuasive in promoting their wares     

Memories of light

The author briefly discusses both optical disc and magnetic media for recording data pointing out that they are complementary to each other. The author then describes the technology involved in write-once optical media and erasable optical recording     

Semiconductor-diode light sources

Electroluminescence can occur as a result of the application of a direct current at a low voltage to a suitably doped crystal containing a p-n junction. It has become apparent in recent years that in certain materials (such as gallium arsenide) and under certain conditions, the efficiency of conversion of electric energy into light can be remarkably high. Since these semiconductor light sources operate at low voltages and low currents and can be made very small, they appear attractive for use in small optical displays. Because they can be switched very rapidly and have fairly monochromatic emission properties, their applications for data transmission are also promising.     

淡妆佳人

三星D1D7i在目前瘦身风潮盛行的家用DV中应该算是大个子了。它拥有一个横版机身，更适合手形较大的男士来使用，在拍摄时的稳定程度要比竖版DV要好得多。D107的机身线条流畅而简约，显得非常大气，透露着一股时尚气息。一枚有效像素80万的1/6英寸的CCD对于     

Spatial light modulators

Near real-time reusable spatial light modulators for coherent optical data processing are reviewed. The PROM, liquid crystal, and electron beam addressed DKDP and oil film light valves appear to be the most promising devices for coherent optical data processing.     

Digital light deflectors

Several electrooptic digital light deflection techniques have been proposed. The maximum number of resolvable deflection positions for all methods is determined, essentially, by economic reasons, the tolerable amount of background fight, and aberrations. In this paper, three different types of deflection methods (split angle, total internal reflection, Wollaston prism) are described. Design, construction details and performance of three deflector models are reported. Combined deflection systems use the advantageous properties of each of these methods to economically obtain the maximum number of resolvable deflection positions. A suggested combination to achieve 1024 × 1024 positions arranged in a two-dimensional field would consist of one total internal reflection stage, seven stages of split angles, and two stages of Wollaston prisms for each dimension.     

Solid-state light valve

Recent developments in the solid-state light valve promise a high-quality projection display. The heart of the solid-state light valve is a cathode-ray tube which operates with a modulated and scanning write beam depositing charge on an electrooptic crystal target. The charge pattern on the target causes optical changes which result in modulation of an external light source. The tube incorporates an erase flood gun to control persistence of the display. This paper discusses an unique reflected light configuration with the target operating at reduced temperature and illustrates the resulting image performance. Accomplishments of contracts with Isomet Corporation on crystal targets of KD2P (potassium dideuterium phosphate) and with EDO, Ltd., on isomorphs of KDP (potassium dihydrogen phosphate) are included. Work being performed by the National Bureau of Standards on crystal perfection and electrode interaction is also presented. The paper concludes with a brief summary of various applications of the solid-state light valve concept, and a short synopsis of results obtained by others that support our enthusiasm for the device.     

Liquid-crystal light deflector

It is shown experimentally that the cell with an n-type nematic liquid crystal may have two functions, light deflection and shutter, and that the cell with a reflective coating film may deflect a light beam about twice the angle achieved with a transmission type of cell.     

Electrooptic light modulators

The field of electrooptic light modulation by means of the Pockels and Kerr effects in crystals is summarized with particular attention to communications applications using the optical maser. AH available data on electrooptic materials are tabulated, and design considerations and operating principles for various modulator configurations are outlined.