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Issue 2 ， 2000
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Vector theory analysis and numerical calculation for any shape profile metallic gratings
Abstract：Based on the Maxwell equation and the boundary continuity of electromagnetic field,the vector theory analysis method-the rigorous coupled wave analysis technique for describing the diffraction of electromagnetic waves by any shape profile metallic gratings for both TE and TM polarization is presented. The effects of grating structure parameters and incidence wave parameter on diffraction efficiency are investigated. The loss of grating is also given.Keywords：diffraction;metallic grating;coupled wave theory- 56
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Published：2020-08-12 -
Imaging of active optical imaging system with a wide field of view
Abstract：Based on the irradiation model and imaging principles of an active optical imaging system, the imaging properties of active optical imaging systems with wide field of view are studied by taking account of the effects of both atmospheric attenuation and scattering. By theoretically studying, the formulas for calculating the irradiance on the imaging plane and the contrast of the image are obtained. The effects of atmospheric attenuation and scattering are analyzed. The transfer properties of the contrast and the effects of the size of the field of view on imaging are studied in detail. The validity of narrow field of view approximation is also analyzed. These results are useful to the design of active optical image systems, image analysis and object recognition.Keywords：point source;active optical imaging system;attenuation;scattering;contrast- 72
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Published：2020-08-12 -
Raytracing of X-ray optical system
Abstract：The raytracing process of an X-ray optical system is described, which may includes any number of mirrors and/or crystals with various figure shapes as well as aperture. The arrangement of optical elements may be coplanar or orthogonal to each other. Diffraction direction of a ray passing a crystal for symmetrical or asymmetrical reflection is calculated from the vector form of Laue diffraction equation. The raytracing program is written in C language, with which not only the ray spot diagram at any position in the optical system can be obtained but also the rocking-curve of a crystal can be calculated. Finally, as an example, the application of the program in calculating the imaging of an X-ray synchrotron radiation beamline system is demonstrated.Keywords：X-ray;raytracing;crystal rocking-curve- 59
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Published：2020-08-12 -
Calibration of graphic distortion and compensation of exposure for dual galvanometer scanning
Abstract：This paper mainly discussed the reasons for resulting in graphic distortion of pre objective dual galvanometer optical scanning system, and compared as well as analyzed the relations between graphic distortion and placement of galvanometers, orientation of image plane, and f-θ error etc. With simulating the f-θ error of 75×75 FOV actual objective lens by least squares model, the accurate formula for correcting graphic distortion was given. In addition, in vector scanning, the non linear velocity of spot movement in image plane will lead to uneven exposure. This paper also offered several ways and formulas to compensate uneven exposure.Keywords：galvanometer scanning;graphic distortion;compensation of exposure- 67
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Published：2020-08-12 -
Multistage bandpass filter used for interferogram signal processing of Fourier transform spectrometer
Abstract：The application of filter technology is the key to the reproduction of measuring spectrum of light source by means of Fourier Transform Spectrometer. Chebyshev bandpass filter was designed by the use of second order sections existing in continuous time active filter Max274 and standard resistors. A good agreement was found between the performance of actual 16 order bandpass filter and the result of primary design. This kind of bandpass filter can be used to limit the measuring frequency width according to practical requirement. It can also availably reduce the influence of AC electrical signal coming from mercury lamp source with AC power source in the course of measuring and singal processing of Fourier transform spectrometer.Keywords：Fourier transform spectrometer;high order active filter;second order section;Chebyshev bandpass filter- 39
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Published：2020-08-12 -
Period measuring and accuracy analyzing method for soft X-ray optical system
Abstract：Recent advances in multilayer mirror technology meet many of the stringent demands of soft X-ray projection lithography(SXPL). The maximum normal-incident reflectivity achieved to data, is 66% for Mo/Si multilayers at 13.4 nm, which is sufficient to satisfy the X-ray throughput requirements of SXPL. These high-performance coatings must be deposited on figured optics with layer thickness error controled in ~0.5%. Uniform multilayr coatings are required for SXPL imaging optics, so maintaining the surface figure is critical to achieve diffraction-limited performance. In this paper, the figured substrate is considered as small super polished planes on the figured curve. By measuring the periods of multilayer on every small plane with small angle diffraction, the deposition speed of the figured substrate can be obtained. For improving the accuracy, every multilayer is measured repeatedly to wipe off the crude and systematic errors, acquire the best value, and calculate limiting error.Keywords：Soft X-ray multilayer;figured substrate;error- 55
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Published：2020-08-12 -
Evaluation and applied analysis of laser beam quality
Abstract：Starting from the concept of M2 factor, this paper analyzed the relation between the M2-factor concept and the innate character of laser, and the factor M2 of some kinds of classical beams. The limitation of the factor M2 was studied. It also compared the appropriate areas for different definitions of laser beam quality and explored the influence factors on laser beam quality and controlling measures.Keywords：laser beam;beam quality;laser;evaluatiion;high-power laser- 50
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Published：2020-08-12 -
LD-pumped room-temperature intracavity doubling solid-state 473nm blue laser
Abstract：Nd∶YAG 946nm quasi-three-level laser system was studied theoretically. The way to realize the operation of 946nm all-solid-state infrared CW laser at room-temperature was presented. Through the optical-system specially designed by computer CAD system which can satisfy the requirement of focus, the maximum output power 120mW of 946nm infrared laser is obtained when pumped by a 2W 808.5nm diode(made in China). At the same time, 10mW 473nm CW blue laser is obtained by intra-cavity doubling of BBO crystal. The slope efficiencies for 946nm infrared laser and 473nm blue laser are 10% and 2%, respectively.Keywords：LD-pumped;quasi-three-level;solid-stated blue laser- 72
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Published：2020-08-12 -
Matching decision on stereo based on D-S evidential reasoning
Abstract：Stereo image matching technique was used to locate the right image pixel position that corresponds to a particular left image pixel. Only by computing a similarity measure between the two images, it often obtain error matching point. This paper presents a new matching decision method based on D-S evidential reasoning, the experimental resutls indicate that this method is reliable.Keywords：stereo matching;Dempster-Shafer′s evidential reasoning;information fusion;matching decision- 33
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Published：2020-08-12 -
Noise reducing scheme on output signal of CCD
Abstract：Based on properties of noise on the output signal of CCD, signal-processing schemes used to reduce the effect of KTC noise and to attenuate 1/f and broadband write noise are analysed. These schemes employ time delay and subtraction to eliminate KTC noise and attenuate 1/f noise. They also include a low-pass function to reduce the effect of broadband write noise. Signal processing schemes described in this paper are double-correlated sampling, dual-slope integration and switched exponential filtering. Each of these schemes' principle is discussed and presented, its transfer functions is deducted in this paper. Performance comparisons are given with emphasis on their applicability in high-speed CCD readout applications.Keywords：charge coupled devices;reset noise(KTC Noise);double-correlated sampling;dual-slope integration;signal noise radio;transfer function- 40
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Published：2020-08-12 -
Real-time Storage Based on HD
Abstract：The realtime storage for digital image is the base of video interpretation. With often recording video signal on the tape, low precision, however, is obtained beacause of the low distinguishing of video tape recorder. A method of realtime video storage is studied in the light of the characteristic of digital image, which make HD be a media through lossless compression of digital image. Realtime restorage for 512?512?8bit video image can be realized by this method, and the architecture is simple and practical. So it is a new video storage method.Keywords：HD;realtime storage;image compression- 44
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Published：2020-08-12 -
Film flattening system in space cameras
Abstract：In the large-size photograph and high-resolution film camera, film flattening is one of the most important technolgoies to the camera. In order to get high film flattening precision and high graphic quality, not only film flattening and releasing should be done well, but also vibration absorption and noise reduction should be designed well. In the paper a more perfect film flattening system is introduced. A calculation method about film flattening accuracy is presented. The effect of limiting vacuum of vacuum pump on the speed of film flattening is analyzed. The methods of vibration absorption, noise reduction and ventilation purification are described.Keywords：film flattening;vibration absorption;noise reduction;prevent pollution- 44
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Published：2020-08-12 -
VHDL Logic synthesis and implementation
Abstract：Interface design for high-speed digital CCD camera, based on VHDL description, was presented. The interface circuit was made of Lattice 1k series CPLD(Complex Programmable Logic Device). As VHDL and CPLD were used incorporately, some circuit functions traditionally provided by hardware would be involved with software for more flexibility. Designer could modify the design while the circuits were running. Some codes with VHDL for interface circuit were given. VHDL logic synthesis was used to solve the problem of optimum design. Timing simulation of circuit was proposed and simulation results were shown. Synthesizability problems of VHDL design are analyzed and studied.Keywords：VHDL;logic synthesis;CCD FPGA;placement and routing;timing simulation- 52
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Published：2020-08-12 -
Giant magnetostrictive actuator and finite element model
Abstract：The new giant magnetostrictive material TbDyFe has the trait of output power large, displacement resolving power high and displaclement range great. If the material is used in the micro-displacement actuator, the performance index of displacement actuator will be greatly advanced, which will impel the development of giant precision process technique. In the paper, the structure and the performance of giant magnetostrictive actuator are introduced, and the model of magnet-machine coupling is analysed by the finite element method. It will redound to the computer simulation and the actuator analysis and its design.Keywords：giant magnetostrictive;micro-displacement;magnet-machine coupling;finite element model- 51
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Published：2020-08-12 -
Speed control of cam mechanism based on neural networks
Abstract：Cam mechanism is widely used in interactive movement systems because of its excellent movement characteristics. But the changing torque and inertia moment make the speed stabilizing control of the systems with cam mechanism very difficult. The changing load torque is the primary one in all the factors that influence the speed control accuracy. This thesis makes full use of the approximating to nonlinear functions capability of neural networks and establishes the load torque neural networks model of the system with cam mechanism. Based on the whole compensating theory, a speed stabilizing control system with neural networks compensatory loop is designed. Experiment results convince that the method works very well and can be used in other control systems with changing load torque.Keywords：cam mechanism;neural networks;speed control- 52
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Published：2020-08-12 -
Development and application of time-resolved fluorescence optical fiber biosensor
Abstract：A time-resolved fluorescence optical fiber biosensor(TFFBS)for biomedical detection is developed for the first time. By using lanthanide ions, especially europium ions as the fluorescent labels of samples, TFFBS can perform time-resolved fluorescence detection from spectral characteristics of europium ions. This instrument has a novel optical system, composed mainly with fiber couplers and optical fiber, for the collection and guiding of both exciting light and fluorescence of samples. Owing to its flexibility and convenience in adjusting, TFFBS has small size and high detecting sensibility. The unstable property below 2.3% was demonstrated in experiments. The mutual correlation in duplicate measurement is 99.9%. The detection limit is 7.3?10-10 g/L for Eu 2 maphthoyltrifluoroacetonate, which reaches the levels reported in foreign literatureKeywords：time-resolved fluorescence fiber-optic biosensor;optical fiber coupler;immunoassay- 54
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Published：2020-08-12 -
Motion control of LDWD realized by drawing exchange file of CAD
Abstract：The character of the laser direct-writing device(LDWD)is analyzed. The key factor that affects the processing efficiency of the device is the drawing which is often varied, and for the program language isnt standard as well, it needs much time to debug motion code. By inputting the processing drawing, and adding ancillary message on drawing, the DXF file for processing drawing can be created using the function of CAD. The interpreting program which can translate the drawing exchange file of CAD into motion code is edited by utilizing the drawing function and the drawing exchange file of CAD. By using interpreting software the efficiency of the device can be improved. The debugging time of motion control program is shorten. The method is given to realize autocode for the device.Keywords：drawing exchange file;motion control code;interpreting software- 57
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Published：2020-08-12 -
Computer aided calculation of angle stiffness of single axis flexible hinge
Abstract：Flexible hinge can realize micro displacement of linear and angle by revolving around its axis, so its usage is widely. One of important performances of flexible hinge is its angle stiffness. When angle stiffness of flexible hinge has been calculated, its displacement can be controlled easily. Hence, acquiring angle stiffness of flexible hinge is very important for its application. However, the angle stiffness is difficult to calculate, especially by manual methods. This article concludes the formula of angle stiffness of single axis flexible hinge by its force diagram. In order to simplify the calculating process the article makes a program for the formula, with which the angle stiffness of single axis flexible hinge can be calculated easily.Keywords：flexible hinge;angle stiffness;computer aided calculation- 49
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Published：2020-08-12 -
Inverted Abel transform based on cubic spline functions
Abstract：The radial distributions of plasma parameters are very important in plasma physics. If the plasma distribution is axial symmetrical and optically thin, the radial distribution of some physical parameters are obtainded by using Abel inversion from measured integral value along radial direction. The inverted Abel transform is necessarily used to compute the X-ray emission radial distribution and measure the electronic temperature and density through multichannel method in laser produced plasma expeirments. Using the cubic spline function method, the inverted Abel transform is numerically calculated from two typical distribution that are gaussian and off-axial distribution. The simulated results show that this algorithm is high accurate, convenient to compute and easy to program.Keywords：Abel transform;cubic spline function;X-ray- 48
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Published：2020-08-12 -
New algorithm insensitive to the piston and tilt errors of reference mirror for phase stepping interferometer
Abstract：A new algorithm insensitive to the piston and tilt errors of reference mirror for phase stepping interferometer is presented. Clearly, if the reference mirror has tilt and piston errors caused by phase-shifting, every pixel on the same interferogram will have different phase-shift values. And by the fact that the phase shifts of all the pixel on the same interferogram are still kept on a same plane, so by least-squares fitting to the phase-shift plane, the errors can be eliminated. The validity of this algorithm has been demonstrated by means of computer simulation.Keywords：phase shifting interferometry;phase shifting errors;least-squares fitting;iterative- 34
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Published：2020-08-12 -
Measuring star with video interpretation in daytime
Abstract：A new method is provided to improve the ability in measuring star in daytime of TV measurement system in the measurement ship. By this method, video image of stars achieved by the TV measurement system on a optical measurement device can be recorded into a computer HD on real time, and the course modification of measurement ship and dynamic calibration can be realized through interpretation of stars video image which is saved in computer HD. The experimental results prove that this method may enhance the ability in measuring star in daytime of optical measurement device and whole measurement precision of measurement ship.Keywords：measuring star in daytime;Video interpretation;dynamic calibration;course modify- 52
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Published：2020-08-12 -
Analysis of 3-D coordinate vision measuring methods with feature points on workpiece
Abstract：D coordinate vision measuring methods with feature points on workpiece are demonstrated, such as structured-light method, laser auto-focusing method, binocular vision method, trinocular vision method, monocular vision method, etc. The characteristics and measuring precision of each method are analyzed in detial, meanwhile the present development and application status are also introduced.Keywords：feature points;3-D coordinates measurement;computer vision- 44
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Published：2020-08-12 -
Development of photoelectric rotary encoders
Abstract：Photoelectric rotary encoder, which is also called photoelectric angel-position sensor, is a kind of digital angle-measuring device combining optics, mechanics and electronics. Owing to its simple structure, high resolution, and high accuracy, the photoelectric rotary encoders have been used generally in the systems of fine angel-position measurement, digital control and digital display. The domestic and foreign development in photoelectric rotary encoders are mainly introduced, and its working principle, developing history are described briefly as well. Some key technologies of photoelectric encoders and its developing trends are summarized at last.Keywords：photoelectric rotary encoder;present situation;prospect- 147
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Published：2020-08-12
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