With the development of super precision machining technology, the requirement for the precision of super-smooth
surfaces measurement has reached ever-higher levels. In this paper, we adopt the phase-shifting interferential microscope
technology, and present a kind of algorithm called Geodesic Erosion which aims at eliminating noises in the wrapping
phase image such as abrupt phase changes, holes, points with low modulation, etc. Experiments show that the system is
effective to remove noises in the wrapping phase image and successful to achieve the unwrapping phase image. The
accuracy of this system may attain nanometer magnitude, while can also meet the topography measurement requirement
for the super-smooth surfaces perfectly.
The precision measurement on surperfinish surface scratch has been currently paid much attention to on electronic
products. To meet these demands, a novel method has been proposed which is based on heterodyne interferometry that
utilizes birefringent lens as beam splitter and cantilever tip as scanning probe to get the measurement values of sample
topography. But the optical nonlinear errors affect the measurement precision of the system. In this paper, we adopt the
Jones matrix to analyze the elliptic polarization caused by the three factors existing at the same time, which are
polarization ellipticity of laser source, installation orientation error and phase retardation of birefringent lens. The
measurement errors of frequency mixing about these elliptic polarization beams arriving at the photodiode detecter are
studied by vector theory. The results show that the measurement errors are periodic errors, and they will change from
1.24nm to 3.94 nm when the magnitude of orientation error of birefringent lens changes from 1°to 5°. Also, the methods
of reducing measurement errors according to the numerical results in the system are suggested. The measurement
precision will be improved by reducing the orientation error or choosing high performance laser source.
This paper describes a technique for the measurement of deep sub-micron flying height based on intensity interferometry, focuses on the introduction of operating principles, system configuration and image visual feedback techniques. Because the flying height is super low, micro pitch or roll of the slider will lead to measuring error. Thus a constant relative position between the optic spot and the slider should be assured. Imaging processing technique is used to obtain the coordinates of both the slider and the optic spot. A detection algorithm of the center of circle is detailed in this paper.
This paper describes the development of software used for the ultra smooth surface roughness measurement system, whose precision reaches nanometer level. The software mainly consists of two independent modules: the image acquisition and the roughness analysis modules. The first module controls the rotation of the phase-shifter and gathers images from the CCD camera. The process is repeated several times according to the means of calculating phase. The second module is used to analyze the sample's roughness. Firstly the images are loaded, and then the phase image is calculated and processed in the light of the unwrapping algorithm. Finally the roughness data are acquired by integrating the unwrapped phase image. The roughness carves on both x and y direction can be readily displayed and the roughness parameters are calculated and simultaneously shown. Then the three dimensional profile is displayed by employing the functions of OpenGL, and the parameter of the three dimensional roughness is also shown. All these results can be readily saved. The software is developed with VC++ 6.0, and has several characterizations as follows: it runs independently without any aid of other software; to depress the influence of noises, ten images are gathered at one time and averaged automatically; through loading image the software can discriminate that whether four-bucket or five-bucket method should be adopted, and choose the corresponding algorithm in the following calculations; the sample's three dimensional profile is also shown directly.
Micro-worktable is an important part of a micro-assembly system, and it implements the translation along X- and Y- axes and the rotation along X-, Y- and Z-axes of the assembly system. In order to amplify the micro-worktable displacement output and improve the micro-positioning accuracy, a novel 3-DOF organ-drive-inspecting micro-positioning worktable was designed and analyzed using modified double-parallelogram symmetrical structure flexure hinge and piezoelectric-actuators. For the symmetric mechanism effectively eliminated the coupling deflection angle and limited the vertical direction motion, the modified double-parallelogram flexure hinge increased the output displacement of X, Y and Z axes. Finite element model of the micro-worktable was established in ANSYS to make its static performances simulation by finite elements method (FEM). Simulation results showed that stiffness and accuracy of the modified double-parallelogram flexure hinge mechanism are higher than general double-parallelogram flexure hinge mechanism, and output displacement linearity is better than single-parallelogram flexure hinge mechanism. Flexure hinge mechanism and piezoelectric-actuator self-features reduce the system complexity, coupling displacement error, and also assure the stable accuracy, high resolution, and high frequent-response of the micro-positioning worktable. Finally, static performance was tested and analyzed through experiments. In experiments, the piezoelectric-power provided voltage to drive the micro-positioning worktable along X, Y and Z axes, and an electric inductance micrometer dial was used to measure the output displacement. Experimental results show that the resolution is 0.04μm for displacement in X, Y, and Z axes, and the maximum stroke length reaches 6μm. The design meets with the requirement of the micro-assembly system.
Measurement of micro structures is a key issue in microtechnology, and it will influence the production efficiency and quality of large-scale integrated circuits. An experimental study on the factors affecting the accuracy of measurement of micro structures has been carried out with a laboratory-built DXY-1 type linewidth measuring system. The experiment results show that the repeatability of the system is better than ±0.005 µm, and the difference between the nominal and measured values is less than ±0.02 µm.
Electron tunneling accelerometer has the advantages of high precision, small volume, low consumption and so on. This paper introduces the design on a lateral dual-element Electron Tunneling Accelerometer. The model, structure design, parameters test and fabrication process are provided in detail. The results of analysis and simulation show that the working frequency of sensor could be up to 2 kHz.
The advanced data storage technology is important to information era. Among all sorts of solutions of high-density storage, near field optical disc technology (NFOD) is high speed and mass storage technology with excellent aptitude and future, and it is the focus of data storage research field in the pioneer technology. Today the research institutes all over the world are speeding their research on NFOD. By using the techniques of solid immersion lens (SIL) and super-low-flying system, it can achieve not only super-high recording density that can be much more higher than traditional optical disks but also the hard disks. In order to improving near-field coupling efficiency of SIL-TO-DISK, the SIL must keep sub micron flying height from the disk, so it is necessary to discuss the research process of real time method to measure SIL-TO-DISK for super-low-flying system. This paper analyses technique foundation and characteristc and its key problem for the flying height measurement, the paper studies several practicing plan of real time measure the clearance even when the SIL-DISK spacing is down to nanometer level for example, relative light intensity method, the capacitance displacement sensors, effective refractive index method for frustrated total reflection, and compare the characteristic and precision of those approach.
The research of high density optical storage system leads to the high density of tracks and pits of the disc. The track pitch of high density optical storage system is much more narrow than that of ordinary optical disc such as DVD. The first step in the production process of both pre-record data and recordable optical discs is mastering. Thus in the high density optical storage system the stable and accurate mastering performance is of greatest importance. This paper presents a control scheme that provides fast, accurate and stable mastering performance. Because of the high density of the track on the optical disc, the conventional control of mastering scheme is unfit for good mastering performance. In this paper we review the development of optical storage system and analyze the problems that may arise when the conventional control scheme is applied to the high density optical disc mastering system. In the proposed scheme, a new tentative control system is designed. The performance of the proposed tentative control scheme is shown by experiments in the high density optical disc mastering system.
Optical Disk Cluster (ODC) drive is the key component of ultra-large capacity optical storage system. The principle of ODC drive is introduced. The measurement and analysis system of dynamic properties of ODC is developed using graphical programming language, LabVIEW, the best software platform of virtual Instruments. The vibration characteristic of ODC is studied. The experiments show that the main reasons of ODC vibration are shaft eccentricity, disalignment of shaft, and inclination of optical disk. As the result, the methods of reducing vibration of optical disk are presented, which can be used to optimizing design of ODC.
In order to meet the development requirements of high density, high capacity and high integration in the field of optical storage, a new scheme for optical recording system is supplied in this paper. At the same time the methods about disc alignment, position and clamping are discussed in details. The principle of flexure hinge is adopted. The results of experiments show that the scheme is feasible, and the setups for optical discs can meet the requirements.