一种新型摆杆式可变光栏

本文介绍了一种新型的摆杆式可变光栏。根据推导出的动环转角与光栏片转角的关系式,用计算机辅助设计选取光栏机构的一组最优化参数,使动环等角转动变换每档光圈时,实际光通量与理论值误差≤8.4%。     

光刻投影物镜可变光阑的结构设计与分析

针对光刻机投影物镜的可变光阑设计对光阑调整范围、安装空间、调整精度的要求,设计了口径为236 mm、调整精度为NA±0.003的连续可变光阑。通过设计与计算236 nm光阑片参数,得到了光阑各组件的结构参数,并采用部分齿轮减小了运动机构的质量和摩擦。为了保证光阑的调整精度和材料应力要求,对光阑的各个部件进行强度校验并对其固有频率进行了分析。结果表明：光阑的关键受力部件（如连接铆钉及传动齿轮）的应力均满足要求,光阑片的固有频率间不存在密频现象。结果证明了提出结构的合理性。     

High-sensitivity fiber-tip pressure sensor with graphene diaphragm

A miniature fiber-tip pressure sensor was built by using an extremely thin graphene film as the diaphragm. The graphene also acts as a light reflector, which, in conjunction with the reflection at the fiber end-air interface, forms a low finesse Fabry-Perot interferometer. The graphene based sensor demonstrated pressure sensitivity over 39.4 nm/kPa with a diaphragm diameter of 25 μm. The use of graphene as diaphragm material would allow highly sensitive and compact fiber-tip sensors.     

相对孔径与曝光量

本文对照相物镜相对孔径的定义、光圈数、像面照度、像面曝光量以及它们之间的关系进行了讨论。     

All-fiber high-sensitivity pressure sensor with SiO2 diaphragm

The design and fabrication of a miniature fiber Fabry-Perot pressure sensor with a diameter of 125 microm are presented. The essential element in the process is a thin SiO2 diaphragm that is fusion spliced at the hollow end of an optical fiber. Good repeatability and high sensitivity of the sensor are achieved by on-line tuning of the diaphragm thickness during the sensor fabrication process. Various sensor prototypes were fabricated, demonstrating pressure ranges of from 0 to 40 kPa to 0 to 1 MPa. The maximum achieved sensitivity was 1.1 rad/40 kPa at 1550 nm, and a pressure resolution of 300 Pa was demonstrated in practice. The presented design and fabrication technique offers a means of simple and low-cost disposable pressure sensor production.     

一种微型温差电制冷器建模与性能分析

温差电制冷技术广泛应用在半导体的降温和制冷中,但由于半导体器件的尺寸越来越小,导致传统的温差电制冷理论和方法不再适用新的环境,尤其是在微型半导体器件中,非线性的热传导规律导致制冷模型和分析方法都发生了改变.文中在深入研究了微型半导体器件中,温差电制冷技术的工作原理和过程.在此基础上,提出了一种微型温差电制冷器的建模方法...     

Field emission pressure sensors with non-silicon membranes

We report on the fabrication of cold cathode emitter and the design parameter simulation of a functional field emission-based pressure sensor. This device comprises a membrane made of metallic compound acting as the anode in front of a flat cold cathode emitter. First, the mechanical deflection of a diaphragm under selected input pressures is modeled. The current density distribution in the deflected diaphragm is then calculated using realistic field emission characteristics from fabricated sulfur doped boron nitride (S-BN) cold cathode device. The total current output was found by integrating the measured current density of the fabricated electron emitter device over the entire diaphragm area of the membrane as function of external pressure. The results show that conventional silicon membranes would pose problems when implemented in a real field emission device, and show how the use of unconventional materials (i.e., TiN) can help overcome these problems.     

A Method of Minimizing the Principal Methodical Error in Measurements of the Spectral Coefficients of Diffuse and Mixed Reflection

We consider the modifications of the measurement technique and construction of the diffuse integrating sphere that make it possible, by replacing a nontransparent screen with an iris diaphragm, to provide additional irradiation of a photoreceiver by radiation reflected from a specimen and thus to minimize, in a wide spectral range, the methodical error caused by radiation losses on the technical holes of the sphere in measuring the spectral coefficients of diffuse and mixed reflections.     

Miniature all-silica fiber optic pressure and acoustic sensors

We present a miniature diaphragm-based Fabry-Perot (F-P) interferometric fiber optic sensor fabricated by novel techniques for pressure or acoustic wave measurement that is only approximately 0.32 mm in diameter. By choosing different diaphragm thicknesses and effective diameters, we obtain a sensor measurement range from 5 to 10,000 psi (1 psi = 51.72 Torr) and a frequency response up to 2 MHz. In addition, the sensor's F-P cavity can be set from micrometers to millimeters with a precision of several nanometers. With the all-silica structure, the sensor is reliable, biocompatible, and immune to electromagnetic interference and has high-temperature sensing capability.     

Noise in miniature microphones

The internal noise spectrum in miniature electret microphones of the type used in the manufacture of hearing aids is measured. An analogous circuit model of the microphone is empirically fit to the measured data and used to determine the important sources of noise within the microphone. The dominant noise source is found to depend on the frequency. Below 40 Hz and above 9 kHz, the dominant source is electrical noise from the amplifier circuit needed to buffer the electrical signal from the microphone diaphragm. Between approximately 40 Hz and 1 kHz, the dominant source is thermal noise originating in the acoustic flow resistance of the small hole pierced in the diaphragm to equalize barometric pressure. Between approximately 1 kHz and 9 kHz, the noise originates in the acoustic flow resistances of sound entering the microphone and propagating to the diaphragm. To further reduce the microphone internal noise in the audio band requires attacking these sources. A prototype microphone having reduced acoustical noise is measured and discussed.     

Diffraction characteristics of optical vortex passing through an aperture-iris diaphragm

The diffraction of an optical vortex through an iris diaphragm which is a close approximation to a circular aperture has been investigated. The results are compared with those obtained from the diffraction of a Gaussian beam through the same aperture. In our findings the diffraction of an optical vortex and a Gaussian beam produce ball bearing sort of structure of darkness and brightness. The singularity of the vortex beam is found to be consistent even after the diffraction through the aperture. The presence of singularity at the centre of diffraction pattern of an optical vortex has been confirmed by interferometry. There is a good agreement between the experimental and numerical results. We propose that these results may find various applications in optical trapping experiments.     

High quality beam shaping by square soft-edge diaphragm combined with liquid crystal spatial light modulator

<正>The square soft-edge diaphragm with round angle is designed by Matlab,and is sent to a liquid crystal spatial light modulator by the computer.In order to obtain precompensation for the following laser system, local diaphragm transmission can be adjusted by feedback signals of surface-channel charge-coupled device (SCCD).This method can reduce the diffraction effect and realize no modulation,high stability,high homogeneity,and large scale laser beam.Several parameters of soft-edge diaphragms which affect the laser beam quality are studied systematically,and the optimized values are obtained.The method can avoid the serious modulation of hard edges and provide soft-edge diaphragms of different shapes in a fast and convenient way for the large scale laser beam system.     

Fly-ear inspired micro-sensor for sound source localization in two dimensions

Inspired by the hearing organ of the fly Ormia ochracea, a miniature sound localization sensor is developed, which can be used to pinpoint a sound source in two dimensions described by the azimuth and elevation angles. The sensor device employs an equilateral triangle configuration consisting of three mechanically coupled circular membranes whose oscillations are detected by a fiber-optic system. The experimental results indicate that significant amplification of the directional cues and directional sensitivity can be achieved with the fly-ear inspired sensor design. This work can provide a basis for the development of miniature sound localization sensors in two dimensions.     

Miniature plasma focus as a novel device for synthesis of soft magnetic FeCo thin films

The Letter reports the first ever application of low energy miniature plasma focus device as a deposition facility for nanostructured thin films. We demonstrate successful utilization of a 120 J fast miniature plasma focus device as a novel facility for the deposition of magnetically soft FeCo thin films. Different gas types and the substrate materials were used to investigate their effects on magnetic properties of the films. The FeCo films deposited on Si₍₁₀₀₎ with hydrogen as the filling gas were found to have an average grain size of 10.8±1.2 nm with narrow size distribution and soft magnetic properties with coercivity of about 6.3 Oe. The experimental coercivity value matched reasonably well with the theoretical calculation done using ripple theory.     

Enhanced applications of speaker-modulated helium–neon laser beam

Wide range of applications using He–Ne laser were carried out employing speaker for vibration modulation. The very simple method was achieved by gluing a mirror to the diaphragm of an ordinary miniature speaker. The technique allows many of the applications that depend on laser absorption coincidences to be performed by a He–Ne laser enhancing by the range of applications in which it can be used and avoiding the complications and expenses needed for sophisticated equipment. Speaker modulation was found efficient and comparable to mechanical chopper modulation. The method is sensitive enough to determine minute changes in index of refraction or transparent material thickness change and suitable for odor emission monitor.     

微小化毛细泵吸环路(miniature CPL)应用于笔记本计算机传热之研究

本文针对目前笔记本计算机CPU在小空间内的高发热量趋势,提出采用毛细泵吸环路（CPL）取代传统热管,实现小空间内的更高效传热。传统大型CPL环路的研究与应用已经相当完备,但当尺寸缩小时会有许多新的问题产生。本文通过实验观察及理论分析,望能发展出适用未来电子产品高发热需求的微小化CPL环路。     

Development of a micromachined piezoelectric microphone for aeroacoustics applications

This paper describes the design, fabrication, and characterization of a bulk-micromachined piezoelectric microphone for aeroacoustic applications. Microphone design was accomplished through a combination of piezoelectric composite plate theory and lumped element modeling. The device consists of a 1.80-mm-diam, 3-microm-thick, silicon diaphragm with a 267-nm-thick ring of piezoelectric material placed near the boundary of the diaphragm to maximize sensitivity. The microphone was fabricated by combining a sol-gel lead zirconate-titanate deposition process on a silicon-on-insulator wafer with deep-reactive ion etching for the diaphragm release. Experimental characterization indicates a sensitivity of 1.66 microVPa, dynamic range greater than six orders of magnitude (35.7-169 dB, re 20 microPa), a capacitance of 10.8 nF, and a resonant frequency of 59.0 kHz.     

成像法测量脉冲激光远场能量密度的模型及不确定度分析

 设计了基于漫反射成像法测量脉冲激光远场能量分布的方案,在相机标定的基础上建立了CCD图像灰度值与漫反射板上脉冲激光能量密度对应关系的数学模型,该模型考虑了漫反射板的漫反射率和CCD像元响应度的空间不一致性,并对不同测量位置的离轴角的影响进行了修正。分析表明:CCD灰度值、镜头透过率、漫反射率和CCD响应度的不确定度传播系数为1,镜头光圈数的不确定度传播系数为2,镜头焦距的不确定传播系数随离轴角增大而增大,成像中心像素坐标的不确定度传播系数在图像顶点处最大。针对相机标定实验中发现的利用Tsai单视角共面点标定相机得到的镜头焦距与实际存在较大偏差问题,指出对于定焦镜头,应该采用其它离线方法进行准确标定;对于变焦镜头,可采用单视角非共面点或多视角共面点进行在线标定。     

Evaluation of a contraceptive device with MR imaging.

The purpose of this investigation is to evaluate the positioning and to confirm the volume concept of the Lea's Shield diaphragm utilizing MR imaging. We evaluated the device in two women, one nulliparous and one multiparous. We were able to comprehensively evaluate the device in both patients and answer all questions regarding anatomical positioning and aspects pertaining to the morphology of the device relevant to its function. MRI may be effectively utilized to evaluate contraceptive devices and their relationship to adjacent anatomical structures. This may enhance the gynecologist's clinical assessment of its correct positioning and efficacy.     

基于亚微米尺度干涉阵列的超小型高分辨光谱仪(英文)

We present an ultra compact and high resolution free space optical spectrometer and demonstrate it by using FDTD simulations. The miniature interferometer-based speetrometer is a series of submicron phase objects on a polymethyl methacrylate（PMMA） film with a CCD as the detector. The speetrum is obtained by solving a system of simultaneous linear equations. The Tikhonov regularization method is used to achieve a resolution at the picometer level. Compared with conventional speetrometers, the proposed device is low-cost and easy to fabricate due to its simple structure. Furthermore, its compact feature renders the device ideal for miniaturization and integration as the systems in microfluidics architectures and lab-on-chip designs.