场致发射显示器驱动电路研究进展及其性能研究

场致发射显示是一种新型的平板显示技术，场致发射显示器继承了传统的阴极射线管显示器的优良特性，兼有液晶等薄型平板显示器的优点，具有广阔应用前景。介绍了几种不同阴极结构的场发射显示器工作原理及相应的驱动电路，分析并比较了二极管型和三极管型两种场致发射显示器的驱动电路，对新型场致发射平板显示器的理论研究具有参考意义。     

后栅结构四针状纳米ZnO场致发射显示器的研制

为了解决二极结构FED驱动电压高的问题,设计制作了后栅式三极结构纳米ZnO场致发射显示器,进行了场致发射实验,验证这种结构的可行性。采用丝网印刷厚膜技术实现后栅极结构FED的制作,工艺简单,实现了较低电压的调制。对影响场致发射性能的栅极电压、阳极电压进行了分析讨论。将阴栅极板和荧光屏封装成5英寸三极结构的场致发射显示器,实现了稳定的场致电子发光显示。     

平行栅结构氧化锌场致发射显示器的研制

用陈化处理过的锌粉为原料,采用高温气相氧化法制备四针状氧化锌材料。应用厚膜、光刻工艺和丝网印刷法制作氧化锌场发射阴极阵列。将阴极板与阳极荧光板制成了5英寸(12.7 cm)单色平行栅结构场致发射显示器(FED)并对其进行了场发射性能测试。分析讨论了影响发射性能的栅极电压、阳极电压以及阴极厚度等参数。该FED在约4000 V阳极电压和300 V栅极电压的驱动下能实现全屏发光。实验结果表明,氧化锌平行栅结构FED具有良好的栅极调控作用,场致发射性能良好,具有良好的应用前景。     

三极场发射显示器中二次印刷型碳纳米管阴极的制备及特性(英文)

结合丝网印刷技术,研发了一种碳纳米管阴极制备法.利用双壁纳米管作为原材料,并加入细小银颗粒,制作了混合纳米管浆料.将混合纳米管浆料制作在传导电极表面,再将普通纳米管浆料印刷在混合纳米管浆料的上面.在链式烧结炉中对烘烤后的纳米管浆料同时进行烧结以除掉有机溶剂.在进行适当的后处理工艺之后,就形成了二次印刷型纳米管阴极,它能显著改善阴极的场致发射特性.制作了二次印刷型纳米管阴极的三极结构场致发射显示器.该显示器具有更高的发光亮度以及更好的发光图像亮度均匀性.与普通纳米管阴极场致发射显示器相比较,它能够将开启电场从2.15V/μm降低到1.75V/μm,并能够将最大场发射电流从735.8μA提高到1 588.5μA.所研发的纳米管阴极制备方法具有很强的实际应用性,且制作成本低廉.     

碳纳米管场发射显示器的研究进展

碳纳米管因具有良好的电子发射特性而成为理想的场发射阴极材料,利用碳纳米管作阴极的场致发射平板显示器件的研究是目前显示技术领域的研究热点之一。报道了场发射显示器（FED）的结构及工作原理、阴极发射材料应具有的特点及碳纳米管在场发射领域中的应用情况。详细地论述了碳纳米管的场致发射特性,包括开启电场、发射电流密度、电流稳定性及发射点密度等,对国内外碳纳米管场发射显示器的发展现状及趋势作了回顾和展望,并对目前所面临的主要问题作了分析,同时提出了一些改进的思路。     

平栅极结构碳纳米管场发射性能实验

研究了碳纳米管(CNT)场发射显示器(FED)三电极结构的平栅极结构,得到了进一步降低场致发射的开启电压和缩小动态调制电压范围的方法,同时也为相关的场发射安全操作提供了借鉴。实验表明:二极结构场发射调制电压范围较大,调制电压达上千伏,而在三电极的平栅极结构中通过调节阳极电压不仅可控制显示亮度,还对栅极调制电路有保护作用。适当升高阳极电压、适当缩短阴极和阳极之间的距离以及阴栅极经老化后可减小栅极调制电压, 同时还能有效的降低场致发射的动态调制电压的范围。这对新一代的显示器研制提供帮助。     

三极结构四针状纳米ZnO场致发射显示器的研究

针对二极式场致发射显示器(field emission display, FED)驱动电压过高的问题, 设计制作了前栅极式三极结构纳米ZnO场致发射显示器, 并进行了场致发射实验, 验证这种结构的可行性.前栅极结构采用喷砂工艺结合光刻技术, 制作出微细的栅孔结构, 实现了较低电压的控制.同时对影响场致发射性能的栅极电压、栅孔开口尺寸和介质层厚度进行了分析讨论.实验结果表明:采用三极结构四针状纳米ZnO场致发射显示器具有良好的发射性能, 是一种有前途的场致发射显示器.     

基于亮度校正模型的多参量权衡与灰度权值算法研究

针对嵌入亮度校正模型的全彩LED显示屏低灰度均匀性差甚至会出现缺少灰度等级的问题,研究了校正算法实施过程中的多维参量,分析了红绿蓝三基色校正参量偏差和扫描图像数据偏差产生的原因及其对各灰度级亮度差值的影响。最后基于LED显示屏驱动控制系统提出参量的权衡公式,根据权衡公式选取各参量最优值,并针对图像数据的最小进位精度这一参量提出一种高精度灰度权值算法,不仅可提高显示屏各灰度下的均匀性指标,而且还可增加LED显示屏上的显示灰度等级。实测结果表明:当选取校正参量的校正精度为8 bit、图像数据的最小进位精度为0.5时,8扫显示屏不能达到均匀性指标的灰度级区间为[42,1];按照权衡公式选取校正参量的校正精度为10 bit、图像数据的最小进位精度为0.25时,均匀性不能达到指标的灰度级区间减小到[20,1],同时相比前者,LED显示屏的起辉级数减小,显示灰度等级增加两级。     

一种适合视频瞄准具的电子分划叠加电路系统

对视频电子分划瞄准具进行了设计。根据视频图像电子叠加原理,完成了屏幕存储映射方式的电子分划线及操作提示符场叠加。系统核心是由单片机、视频叠加显示芯片、数字电位器和单稳态延时电路组成,具有叠加图像与场景图像同显、手动二维调节瞄准分划线位置及改变OLED亮度对比度、热图极性转换和手动非均匀校正等功能。     

增强碳纳米管场发射性能的沟槽形冷阴极制作(英文)

基于烧结工艺和丝网印刷技术,研发了一种新的沟槽形冷阴极.底部绝缘层由黑色绝缘浆料被烧结后制成,且在底部绝缘层中存在倾斜面.将银浆丝网印刷在条形电极上,依次经烘烤和烧结工艺后形成银电极.利用细砂纸,对银电极进行适当的抛光工艺,以便获得光滑的电极表面.由于特有的银电极形状,从而易于获得更大的场增强因子.将碳纳米管制备在银电极上,形成场发射极.致密的碳纳米管层完全覆盖银电极表面,特有的边缘场增强效应能够使得碳纳米管发射出更多的电子.顶部绝缘层则用于抑制碳纳米管的横向电子发射.结合沟槽形冷阴极,制作了三极结构的场致发射显示器,该显示器具有良好的场致发射特性及优良的发光图像均匀性.与普通冷阴极场致发射显示器相比,沟槽形冷阴极场致发射显示器能够将开启电场从1.86V/μm降低到1.78V/μm,将最大场致发射电流从1 537μA增加到2 863μA,且将最大发光图像亮度从1 386cd/m2提高到1 865cd/m2.该制作技术在场致发射显示器中具有较强的实际应用性.     

Self-organization of five species in a cyclic competition game

Cyclic competition game models, particularly the “rock–paper–scissors” model, play important roles in exploring the problem of multi-species coexistence in spatially ecological systems. We propose an extended “rock–paper–scissors” game to model cyclic interactions among five species, and find that two of the five can coexistent when biodiversity disappears, which is different from the “rock–paper–scissors” game. As the number of fingers is five, we named the new model the “fingers” game, where the thumb, forefinger, middle finger, ring finger, and little finger cyclically dominate their subsequent species and are dominated by their former species. We investigate the “fingers” model in two ways: direct simulations and nonlinear partial differential equations. An important finding is that the number of species in a cyclic competition game has an influence on the emergence of biodiversity. To be specific, the “rock–paper–scissors” model is in favor of maintaining biodiversity in comparison with the “fingers” model when the variables (population size, reproduction rate, selection rate, and migration rate) are the same. It is also shown that the mobility and reproduction rate can promote or jeopardize biodiversity.     

Contrastive analysis on tone between Putonghua and Taiwan Mandarin

The differences of the pitch and duration of Chinese syllables between Putonghua （PTH） and Taiwan Mandarin （TM） were studied. The speech materials to be used are not only isolated syllables, but also sentences. The results reveal that： For the isolated syllables, T1 and T2 in TM are influenced by Minnan dialect, therefore their pitch are lower than those in PTH. T3 is fall-rise in PTH, while it is fall in TM. Moreover, the syllable duration sequence for different tone is T3〉T2〉T1〉T4 in PTH, while it is T1〉T2〉T3〉T4 in TM. For the syllables in sentences, T2 is mid-rise in PTH, while it is mid-level in TM. And the T3 is longer than T4 but shorter than T1 or T2 in PTH, while it is the shortest in TM. Furthermore the effects of prosodic phrase boundary on duration for different tones are almost the same in PTH, but the lengthening part of T1 or T2 is longer than that of T3 or T4 in TM.     

Experimental study on downstep in Chinese intonation

Downstep in pitch contour of Chinese Putonghua is examined using subtly designed sentences by controlling tone combinations. The results show both automatic and nonautomatic downstep phenomena exist in Chinese. In non-automatic downstep, low tones compress downwards the pitch range of the following syllables. and the main influence of downstep is on topline. Low tone not only lower the topline behind it, but also raise the high tones before it, the effects are compatible with each other. In automatic downstep, the topline of pitch contour in intonational phrase is presented as a linear downtrend, but it differs among speakers due to the effect of personal stress practice. In comparison with downstep phenomenon in other tone or non-tone languages, the downstep ratio in Chinese is not constant, and the domain of downstep is not limited within the adjacent tones.     

Abelian-Higgs phase of SU(2) QCD and glueball energy

It is shown that SU(2) QCD admits an dual Abelian-Higgs phase, with a Higgs vacuum of a type-Ⅱ superconductor. This is done by using a connection decomposition for the gluon field and the random-direction approximation. Using a bag picture with soft wall, we presented a calculational procedure for the glueball energy based on the recent proof for wall-vortices [Nucl. Phys. B 741(2006)1].     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Signal generation in an isotropic medium in scanning electron acoustic microscope

Based on the research in Ref. [5][Materials Science and Engineering, 1989; A122： 57 63], an improved model of heat source is set up, the different modes of Lamb wave in an isotropic sample generated by a chopped electron beam at frequency f are obtained with integral transform and normal function expansion method, and the output signal of PZT coupled at the back surface of the sample is found out. The generation mechanism of SEAM （Scanning Electron Acoustic Microscopy） signal is discussed. It shows that the SEAM is a near field imaging technique with high spatial resolution and its best lateral spatial resolution is about 2√2α （α is the radius of the focused electron beam）. Some of experimental results of SEAM images are presented in the paper and it shows that the spatial resolution of SEAM is better than 0.5 μm and smaller than the thermal diffusion length of the sample. Therefore the character of near field imaging in SEAM is also proved experimentally.     

High efficiency filtering using two-dimensional photonic crystal coupled cavity structures

Transmission spectra of coupled cavity structures (CCSs) in two-dimensional (2D) photonic crystals (PCs) are investigated using a coupled mode theory, and an optical filter based on CCS is proposed. The performance of the filter is investigated using finite-difference time-domain (FDTD) method, and the results show that within a very short coupling distance of about 3λ, where λ is the wavelength of signal in vacuum, the incident signals with different frequencies are separated into different channels with a contrast ratio of 20 dB. The advantages of this kind of filter are small size and easily tunable operation frequencies.