DESIGN AND PERFORMANCE OF SHAPING DEFLECTORS FOR VARIABLY SHAPED ELECTRON BEAM LITHOGRAPHY

In order to obtain uniform exposure in variably shaped electron beam lithography,the beam current density and edge resolution on the target must not change for different spotshapes and sizes.The key to the goal is the appropriate design of shaping deflectors.A linearand rotation compensation approach is presented.Values of linear and rotation compensationfactors versus the distances between electron source image and centers of deflectors are measuredon an experimental electron beam column with variable spot shaping.The experimental resultsare in good agreement with the calculated ones.     

变形电子束曝光机成形偏转器的设计和性能

在变形电子束曝光机中,为使曝光均匀必须保证靶上束斑电流密度物边缘分辨率不随束斑形状和尺寸的变化而改变。实现这一目标的关键是正确设计成形偏转器。本文讨论采用高灵敏度平行板偏转器实现成形偏转时,为达到上述目标应进行的线性补偿和旋转补偿的设计计算方法。给出了用实验方法改变电子源象与偏转板几何中心的轴向距离所测得的线性补偿因子和旋转补偿因子的值。实验结果与计算值符合较好。     

平行板偏转系统的几何象差和优化设计

本文从理想均匀静电场偏转系统三级几何象差的公式出发,导出了由两对互相垂直的偏转板组成的平行平板偏转系统的三级几何象差公式。这些公式不但可用来快速估算偏转象差,还可用来作为校验数字计算程序的理论模型。从水平和垂直方向偏转象散和场曲的影响应相同这一要求出发,提出了一种优化设计方法。在给定偏转区总长度和两对偏转板之间的距离后,可以计算出每对偏转板的最佳长度。文中给出了设计数表,并比较了平行平板偏转系统和八极偏转系统的优缺点。     

High-speed optical Fourier transformer

A new type of high-speed signal processing or analyzing device-the picosecond Fourier transformer-is proposed. The device can be used to obtain the Fourier transform of the time-dependent intensity of an optical signal. The device makes use of the spatially distributed electrooptic modulator or deflector, and has the potential for terahertz bandwidth and picosecond time resolution. Practical devices are considered and their performances (bandwidth, frequency resolution, etc.) are discussed. The operation of the proposed device is demonstrated in the microsecond range by a preliminary experiment using LiTaO3e-o deflectors.     

MULTIPOLE ELECTROSTATIC DEFLECTORS FOR OBTAINING UNIFORM DEFLECTION FIELD

The general field solutions are presented for two kinds of infinitely long multipoleelectrostatic deflectors.A method is given to obtain uniform field near the optical axis.We calculated sixforms of deflectors,the concerned formulas and data are given.The relationship and difference between twokinds of deflectors are analysed.     

Numerical computation of the deflection fields in magnetic yokes with wedged coil-sections and in electrostatic deflectors with planar electrodes

The computational methods of deflection fields in magnetic yokes with wedged coil-sections and electrostatic deflectors with planar electrodes are discussed. The magnetic yokes with wedged coil-sections can be combined into various shapes of magnetic deflectors, which may offer a variety of choices for adjusting the deflection field distributions to reduce the deflection aberrations more effectively. An advantage of the planar electrostatic deflectors is the simplicity in structure, which might allow the deflectors to be used in the deflection array of multi-electron beam lithography systems. Based on the methods described in this paper two computer programs have been developed. As examples, the deflection field distribution of some typical deflectors have been computed.     

多极静电偏转器获得均匀偏转场的方法

本文推导了两种类型的多极静电偏转器在无穷长情况下场分布的普遍解;提供了多极静电偏转器在光轴附近获得均匀偏转场的方法;计算了六种实用的多极静偏器,给出了有关公式和数据,分析了两种多极静偏器之间的联系和区别。     

High-speed CAVLC encoder for H.264/AVC using parallel zig-zag scanning

A high-speed context-based adaptive variable length coding (CAVLC) encoder for H.264/AVC is presented. Since CAVLC scans residues in a block one by one to obtain the statistics of the data to be encoded, it requires a large number of cycles. In the proposed scheme, two residues are scanned in one cycle to reduce scanning time by half.     

Control Schemes for Driving Electro-optic Array Beam Deflectors

The beam deflectors based on electro-optic phased array（EOPA） is mainly described, and then an analysis on existing control schemes for driving the EOPA beam deflectors, based on custom hard-wired electronics or based on software in a microcontroUer, is made. Compared with these, a driving and control system for a multi-channel EOPA beam deflector is presented, in which the control assignment is implemented with a field programmable gate array（FPGA） chip. For different performance requirements, two control schemes, one with the serial scheme and another with the parallel scheme, have been explored and rapidly prototyped in Xilinx FPGA chips. With the control structures for the EOPA beam deflector, scanning rates of 588 kHz and 5 MHz can be respectivelv reached.     

电光偏转器的矩阵表示和应用

用光线追述的方法，导出了电光偏转器的矩阵表达式，是著名的ＡＢＣＤ矩阵的扩展，它包含了电光偏转器的时变项。井用矩阵光学的理论对由电光偏转器对构成的激光脉冲整形系统进行了研究，对实际应用的电光偏转器对参数的一致性、电脉冲的同步精度及光路排布提出了要求。     

高速A/D转换器的研究进展及发展趋势

介绍了高速高精度A/D转换器技术的发展情况、A/D转换器的关键指标和关键技术考虑;阐述了高速高精度A/D转换器的结构和工艺特点;讨论了高速高精度A/D转换器的发展趋势.     

非子午绕组偏转器磁场的分析与计算

本文给出了鞍形和环形非子午绕组偏转器磁标位和特性函数的解析式.对彩色显象管和电子束曝光机等的偏转线圈设计具有实际意义.理论计算与实测结果符合良好.     

基于自旋运动的高速弹头成像方法

高速弹头目标成像是雷达领域的研究热点与难点。不同于常规目标,高速弹头在沿弹道运动的同时常伴随特定的自旋运动,使得雷达回波包含的多普勒信息更为复杂,对雷达高分辨成像提出了更为严峻的挑战。针对这一难题,该文从3 个层面对基于自旋运动的高速弹头成像方法进行了研究。首先研究了具有轨道运动并伴随自旋运动高速弹头的雷达回波特性,揭示了回波相位信息的变化特点;其次,基于回波特性分析结果,提出了一种基于Wigner-Hough 变换(WHT)的自旋弹头目标回波轨道运动补偿方法以及基于自旋运动的成像方法;最后,利用仿真数据对提出方法的有效性以及基于自旋运动成像方案的优势进行了测试,结果表明:在达到一定信噪比时该文成像算法性能稳健,较好地解决了高速弹头的速度估计难题和成像算法的复杂性问题。      

Laser scanning for electronic printing

The use of laser scanning techniques for acquisition and printing of images is reviewed with primary emphasis on the printing application. Following an introduction to the basic configuration of laser scanners and to the terminology of this field, some of the principal characteristics of these scanners are summarized. A short overview is given of the key components of scanners, i.e., lasers, modulators, and light deflectors. The integration of these and other components into complete scanning systems is then described, including discussion of optical design issues and several examples of practical optical system design for polygon scanners. Holographic scanners and some of their design considerations are discussed. The electronic and mechanical techniques required for satisfactory scanner design and construction are described. Finally, the embodiment of various design approaches into practical scanners is illustrated by a survey of some existing printer products.     

采用一级束控的声光偏转器

报道采用一级束控的声光偏转器，其带宽和衍射效率均明显优于传统器件结构的实验结果。它是高频宽带声光偏转器件发展采取的合理途径。     

用串接电光偏转器提高时空变换装置进行激光脉冲整形的能力

介绍了在时空变换装置中用两个电光偏转器串接和并接的工作原理 ,从理论上分析了用其提高激光脉冲整形的能力 ,进行了激光脉冲削波实验 ,实验结果与理论分析一致。用两个偏转器串接后 ,大大提高产生整形激光脉冲的能力     

双折射对高倍速光驱读盘的影响

从光学角度,通过对光盘光学读盘系统的理论分析,提供了光盘双折射现象对高倍速光驱运行影响的理论根据。得出光盘双折射现象,影响了扫描光斑的成形质量和输出光强的稳定性,从而严重影响了对光盘信息轨道的正常扫描,甚至循迹失败。通过对高倍速光驱实际数据读出率分析,首次从专业使用角度,模拟了光盘在高倍速条件下的应用状态,为高倍速CD及DVD光盘的应用研究,提出了使用新的分析手段的可能性。     

基于USB的DMA方式实现CCD高速数据采集

提出一种CCD用于通用串行总线(USB)高速数据采集系统设计的新方法。通过对USB及其DMA传输方式分析,采用无外部缓冲区的结构实现数据的高速传输．具有精度高、结构简单、方便易行等优点。详细描述了硬件、固件、驱动程序及应用程序的设计情况。实验证明,该系统可实现CCD的高速高精度数值量化及数据传输。     

High-speed electrooptic deflector and its application to picosecondpulse generation

New types of electrooptic deflectors with high speed and high efficiency, which are useful for ultrafast optical switching and ultrashort optical pulse generation, are described. These deflectors are driven by an X-band standing wave along the microstrip line on an electrooptic crystal. A time-varying spatial slope of the refractive index is induced in the crystal by the electric standing wave. As a result, the ultrafast deflection is carried out. The operation of such deflectors constructed on a LiTaO₃ crystal using a 514.5-nm CW argon laser and a 9.35-GHz driving frequency was confirmed experimentally. In addition, the optical pulse compression from CW to 9.35 GHz, 16 ps was carried out with a diffraction grating, and picking out the 18.7-GHz, 8-ps pulse train was also carried out using a slit as a temporal window     

Analysis of electrostatic small-angle deflection

Electron beam aberrations resulting from deflection by two sets of similar, mutally perpendicular electrostatic deflectors have been studied. The analysis is applicable to the cases where the beam can be treated as a collection of noninteracting individual electrons deflected through a small angle by spatially smooth fields. The analysis shows that, with the types of electrostatic deflectors commonly used, anastigmatism cannot be achieved unless external corrections are employed.