数据压缩技术在LED大屏幕中的应用

ＬＥＤ大屏幕作为一种较新的数字图象显示设备，随着其技术的发展，现在已出现了全彩色ＬＥＤ大屏幕，但随之而来的便是图象数据量的增加，给数据传输带来的很大压力，此文根据数据压缩技术的发展，结合ＬＥＤ大屏幕的特点，探讨了数据压缩技术在不同种ＬＥＤ大屏幕显示设备中的应用。     

转拍白光再现全息肖象的研究

本文介绍了我们在转拍白光再现的全息肖象方面的研究工作.讨论了拍摄工作中所需要特别注意的若干问题.如:参物光束比的选择、肖象尺寸大小的估算、视角的估算、获得高衍射效率的化学处理的方法、获得高信噪比的化学处理的方法等.     

Group refractive index measurement by fringes of equal chromatic order

Fringes of equal chromatic order in transmission across a thin liquid or a thin solid sample inside a wedge interferometer, followed with a grating spectrograph, are produced. A single-shot interferogram of the air and sample regions is recorded. Locations of fringes maxima in the air region are fitted in a numerical procedure based on Cauchy's dispersion function. Then it is used for measuring the interferometric gap thickness. The order of interference in the sample region is represented by a third-order polynomial in the wavenumber for deducing the sample group refractive index. An error analysis of the measured group refractive index is given. The method is applied for measuring the group refractive index of water and mica samples across the visible spectrum. The method measures both the sample thickness and its group refractive index. It is static with no moving parts and suitable for thin liquid or solid samples without immersion liquids.     

Organic light‐emitting diodes with multiple photocrosslinkable hole‐transport layers

We report on photocrosslinkable hole‐transport polymers and their use as photodefinable hole‐transport layers in organic light‐emitting diodes. The polymers were obtained by copolymerization of bis(diarylamino)biphenyl‐based acrylate monomers with cinnamate‐functionalized acrylate moieties. Polymers with a range of redox potentials were obtained by varying the substitution patterns of the bis(diarylamino)biphenyl units. The 2 + 2 cycloaddition of the cinnamate moieties following UV irradiation renders the material insoluble. This allows for patterning of the polymer and simultaneously enables the fabrication of multilayer structures from solution. Hole mobilities were measured in these copolymers with the time‐of‐flight technique. Their performance as hole‐transport layers in light‐emitting diodes, with tris(8‐hydroxyquinolinato)aluminum as the emitter and electron‐transport layer, is evaluated. Electroluminescent devices with multiple hole‐transport layers having different ionization potentials were fabricated from solution, and the quantum efficiency of these devices was greater than that for devices based on a single hole‐transport layer. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2726–2732, 2003     

发光二极管光、色测试系统

为适应特殊照明用白光发光二极管(white light—emitting diode以下缩写为WLED)研制开发的需要，设计加工了φ100mm的积分球，通过光纤与现有的荧光分光光度计测量单元耦合，构成LED光、色测试系统。该系统首先给出LED的相对光谱功率分布，据此计算出LED的总光通量等光、色参数。这种方法避免了用一般光度计测总光通量时必须进行色修正的麻烦，也避免了因色修正不充分所带来的较大误差。     

Charge injection into disordered molecular films

Light‐emitting devices made by organic or inorganic dielectric films placed between two metal electrodes emit light because of the radiative recombination of positive and negative charge carriers entering the dielectric from the anode and cathode sides, respectively, under applied voltage. Standard vapor‐deposition technology of the device construction suggests the remarkable disordering at the metal dielectric interface and in the structure of dielectric film. The structural imperfections strongly affect carrier injection and transport, device efficiency, performance, and stability. In this article we describe the effect of disordering on the injection current through the dielectric layer and discuss the implications for the device performance. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2601–2621, 2003     

MOCVD生长InGaN/GaN MQW紫光LED

利用LP－MOCVD系统生长了InGaN/GaN MQW紫光LED外延片，双晶X射线衍射测试获得了2级卫星峰，室温光致发光谱的峰值波长为399.5nm，FWHM为15.5nm，波长均匀性良好。制成的LED管芯，正向电流20mA时，工作电压在4V以下。     

Luminescent copoly(aryl ether)s consisting of alternate oxadiazole and 1,4‐distyrylbenzene derivatives: Synthesis and characterization

In an effort to decrease the electron‐injection barrier from the anode electrode, four copoly(aryl ether)s ( P1 – P4 ), consisting of alternating isolated electron‐transporting [2,5‐diphenyl‐1,3,4‐oxadiazole for P1 and P3 and 5,5′‐diphenyl‐2,2′‐p‐(2,5‐bishexyloxyphenylene)‐bis‐1,3,4‐oxadiazole for P2 and P4 ] and emitting chromophores (1,4‐distyryl‐2,5‐dihexyloxybenzene for P1 and P2 and 1,4‐distyryl‐2,5‐dihexylbenzene for P3 and P4 ), have been synthesized by the nucleophilic displacement reaction between bisfluoride and bisphenol monomers. They are basically amorphous materials with 5% weight‐loss temperature above 400 °C. The photoluminescence spectra and quantum yields of these copolymers are dependent on the compositions of the two isolated fluorophores. The highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels of these copolymers have been estimated from their cyclic voltammograms. All the observations directly prove that the oxidation starts at the hole‐transporting segments. The electron affinity can be enhanced by the introduction of isolated electron‐transporting segments that lead to a charge‐injection balance. Single‐layer light‐emitting diodes (Al/ P1 – P4 /ITO glass) have been fabricated. P1 and P2 reveal blue electroluminescence, and P3 and P4 reveal purple‐blue electroluminescence. Moreover, the incorporation of bisoxadiazole units increases the electron affinity and reduces the turn‐on electric field better than one oxadiazole unit. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2765–2777, 2003     

Multiregion, multigroup collision probability method with white boundary condition for light water reactor thermalization calculations

A multiregion, multigroup collision probability method with white boundary condition is developed for thermalization calculations of light water moderated reactors. Hydrogen scatterings are treated by Nelkin's kernel while scatterings from other nuclei are assumed to obey the free-gas scattering kernel. The isotropic return (white) boundary condition is applied directly by using the appropriate collision probabilities. Comparisons with alternate numerical methods show the validity of the present formulation. Comparisons with some experimental results indicate that the present formulation is capable of calculating disadvantage factors which are closer to the experimental results than alternative methods.     

Interferometric determination of refraction and dispersion of human blood-serum, saliva, sweat and urine

Multiple-beam interference fringes of equal chromatic order are produced in air and liquid sample interferometric gaps. The two gaps are of the same thickness and simultaneously enclosed in a wedge interferometer. A single shot interferogram containing fringes in the two gaps is sufficient to deduce the needed experimental data. Locations of the fringe maxima, in the two gaps, are introduced in a non-numerical procedure for determining the gap thickness and the liquid-phase refractive indices across the visible spectrum. The method has been used for measuring the phase refractive indices of human blood-serum, saliva, sweat, urine and water liquids. A third-order polynomial dispersion relation is applied for fitting the measured phase indices. Group refractive indices have been derived and fitted to the same dispersion formula.