2010 Vol. 3, No. 5
Laser-based direct-writing techniques have gained increased interests in the microelectronic industry, which have some outstanding advantages such as short processing cycles, strong flexibility, no mask, and low environmental requirements. A new technology called laser micro-cladding technology was presented in this paper and the principles and characteristics of the technology were described in detail. On the basis of above researches, the equipment for laser micro cladding was assembled, then by studying the principle of interaction between laser and matter, the formation mechanism of laser micro cladding electronic pastes was analyzed. Finally, the applications of the technology to micro-electronic, optoelectronic and sensor areas were illustrated. Moreover, the development of this technology was predicted, and it was pointed out that the technology will show good prospects in fields of hybrid integrated circuit substrates, micro-sensors, micro-heaters, plane passive electronic devices, discrete devices, biochip and electronic packages.
The principles and structures of Surface-emitting Distributed-feedback Bragg(SE-DFB) semiconductor lasers, especially curved-grating coupled SE-DFB lasers, are described, then, their characteristics are discussed and compared with that of other semiconductors. It points out that the SE-DFB lasers based on special diffractive characteristics of curved grating can achieve the mode control and two-dimensional leaky-mode coupling of laser arrays, and can obtain the laser with narrow line width(typically 0.08 nm), small divergence angle(typically 0.5 mrad), high brightness(3 W(CW) near-diffraction limit emitting from a single device) and high power(73 W maximum in a single device and kW level in arrays). After reviewing the development, present status and new opportunities in future of the SE-DFB devices, it emphasizes that as the curved-grating coupled SE-DFB has both strengths from side emitting and surface emitting devices, it will have great research significance and wide application prospect by introducing into semiconductor lasers and arrays with different material systems and structures.
Surface plasmon polaritons(SPPs) are the wave modes propagating at the interface between a metal and a dielectric. Firstly, the basic characteristics and the excitation modes of SPPs are introduced briefly in this paper. Then, a new method to produce coherent extreme ultraviolet radiation based on the light field enhancement of Surface Plasmon Resonance(SPR) is described, which can greatly improve the photon flux of a light source. The new application of SPPs in the fields of biology and medical treatment is analyzed, and the major technologies and principles of curing cancer are discussed. Moreover, the development and application of several kinds of new light sources and energy sources are introduced, meanwhile, the new processes and technologies of solar cells, photonic chips and integrated circuits are summarized, including some of the most improtant achievements made in recent years. Finally, the rapid development and enormous contribution of SPPs to the field of optical storage is discussed.
To implement the high resolution imaging of a fast motion target in a longer distance, the key techniques of a multi-beam Fourier telescopy are preliminarily analyzed in this paper. On the basis of the system composition, the key techniques in optical sub-system, mechanical sub-system, electrical sub-system and software sub-system are discussed separately. In optical subsystem, the key techniques are focused on the main specifications of laser sources, phase detection elements, acousto-optic frequency shifters and opto-electric tubes; and in mechanical sub-system, it is pointed out that the directing and tracking of the telescopy, fast-switch of beams and supporting structure of primary mirror should be paid more attention. Furthermore, the electrical sub-system emphasizes the synchronization control, electromagnetic shielding and power distribution and the software subsystem lays the stress on the fast switch of beams, synchronization of changing of locations and angles and image restoration. The analysis and discuss in this paper will be provide a reference for the design of multi-beam Fourier telescopy.
Recent developments of Mg2Si films are reviewed. On the basis of the crystal structure of Mg2Si, the basic properties, preparation methods, and application prospects of the films are presented. The researches show that Mg2Si is a kind of semiconductor with narrow-band-gap, which has good applications in photovoltaic and thermoelectric devices. Furthermore, the film is a new kind of environmental-friendly semiconductor material, and because the compositions of elements are rich in strata and non-toxic pollution, the materials attract great attention. In the technique of epitaxial growth, the relatively mature methods include molecular beam epitaxy, pulsed laser deposition, reaction-diffusion and so on. However, these methods have the problems of harsh preparation and poor quality of the thin film. Finally, current problems and future research trends of the materials are briefly discussed.
Extreme UltraViolet Lithography(EUVL) has been regarded as a promising lithographic technology following ArF immersion lithography for the 32 nm hp node and beyond and the EUV optical exposure system consisting of a illumination system and a projection system is a key part in the EUVL. This paper introduces several kinds of EUVL tools at home and abroad and gives their optical specifications. Then, it summarizes the principles of optical design for EUVLs and reviews the design requirements for the illumination and projection systems, respectively. Finally, it describes the design methods of illumination and projection systems in EUVLs, especially, it discusses a aspheric 6-mirror projection optics which is suitable for 22 nm EVUL technology and gives the improvement method of illumination uniformity for the illumination system.
A kind of focusing structure of space camera is presented, which adopts a kind of precision harmonic gear drive. The wave generator in the device is combined with an elliptic cam and a flexible bearing and its output shaft connected ball screws translates the rotational motion to the linear motion and drives the focusing mirror repeated moving along a linear guide. The output rigid wheel is connected with an absolute encoder to detect the displacement of focusing movements. It has the characteristics of big transmission ratio, high precision, compact structure, high efficiency, smooth running etc. According to the practical application of this harmonic gear drive in the space camera, the location relationship between the displacement of focusing structure and the focal plane movement is derived, and the system error is analyzed. Then, the system accuracy is tested with an open-loop control method. Experimental results show that transmission ratio of the instrument is 1∶ 70, and the repeated positional accuracy is 2 m, which meets the requirements of practical applications.
A set of optical measuring centering device is designed, which is composed of an area array CCD camera, an set of optical lens, image processing circuits, a red LED lamp-house, and a spherical surface reflector. The measuring principle of the device is introduced. The measuring objects are arranged in isosceles triangle, and the image of object is collected by a area array CCD and is processed in real time by the image processing circuits. At the same time, four dimension coordinate data(X,Y,X, and rotation angles) are calculated. The calculation expressions of the coordinate of spot image, the distance between the two planes and so on, are deduced and the measuring precision is analyzed. Experimental results indicate that the deviation of position is less than 1 mm and the deviation of angle is 0.24, which shows that the device can realize the high-precision, automatic and expeditiousness measurement.
A multichannel optical system working in 300-1 100 nm was designed to detect the information of objects in the multi-band, which could obtain images at the same time in the near ultraviolet, visible and near infrared ranges. As the system was easy to produce stray light and ghost images due to reflecting of barrel and prism, the stray light and ghost images were simulated and analyzed with the help of Light Tools software. From the simulation results, it is shown that the incidences out of the field in the range of 11.7-18.3 and -11.7--18.3 can be reflected by the up and down surfaces of the prism, and then be focused on the image surfaces of the three detectors to form the ghost images; the incidences in the range of 6.2-9.8 and -6.2--9.8 can be reflected by the barrel to form stray lights. The analyzed result was approved by the image achieved from the multichannel system, and it indicates that the analysis is a contribution to design and manufacture of multichannel system. Several kinds of methods to decrease the stray lights and ghost images was proposed and they have been proved to be effective.
A novel method for the sub-pixel image registration based on phase correlation was introduced, which could be used to detect the movements of video sequences exactly, and could obtain the video outputs stably. Firstly, two images translated based on the phase correlation technique were registered, and the paraboloid surface fitting method based on least-square was used to estimate displacement parameters of the images. Then, the sub-pixel motion vector between the two sequential images could be exactly detected. A smooth algorithm in transform formula of the sub-pixel motion compensation was adopted to avoid the mosaics of images and to improve the precision of image compensation. In order to verify the algorithm in experiments, some sample simulations were performed. The results show that this method can detect the shift parameters accurately and efficiently, which makes it possible to estimate image displacement with 0.01-pixel accuracy. Further more, the maximum error of registration is only 0.008-pixel, and the root of mean square error of image compensation is also less than 0.5.
In order to test the identification algorithms for a star map and evaluate the performance of a star sensor, a CCD star map simulator was proposed and the star map simulation software was developed in this paper. The system used a high-resolution display device and a parallel light tube to simulate the parallel light of an infinite distance to obtain the high quality star map. The validation on star map by an attitude determination algorithm was also presented. By calculating the attitude angles for three stars more accurately, more than 100 star maps were analyzed. The results indicate that the positioning accuracy has reached 98.1%. The designed simulator has been used in a practical operation, the experimental results show that it can offer good information for verifying star map identification algorithm and evaluating star sensor performance, and it also can shorten the development cycle.
The design and manufacture of an elliptic mirror used in remote sensing was described in detail. How to choose the materials of a lightweighted mirror was discussed and the applications of the mirror to vacuum cryogenic environments were introduced. Based on the analyses of effects of different shapes of lightweighting holes, the structure of mirror was designed. By supporting the mirror with a belt hanging system, the gravity effect and the ultra low temperature effect were analyzed with a finite-element software. Furthermore, the practical lightweighting manufacture was carried out in the routing function of a computerized numerical control machining system, and the lightweighting ratio of elliptic mirror obtained has exceeded 33%. In order to eliminate the residual stress and microcracks introduced in the process, the mirror was disposed by a chemistry etching, and processed by a zone polishing machine on local. Results show that the surface error after polishing reaches 0.022(rms, =633 nm). The experiment of temperature variation was done in a small range and the change of surface error is 0.03 nm.
As vibration errors are the crucial source of error in a high accuracy interferometric test, this paper researches the effect of mechanical vibration on the phase shifting stability. It establishes vibration error models and simulates the immunity of vibration by using the three-step algorithm, five-step algorithm, seven-step algorithm and thirteen-step algorithm, respectively. The results show that the thirteen-step algorithm is the best in immunizing the vibration. For the results agreed with that in other literature, it proves the simulation in this paper is believable. To some extent, the method can give a reasonable prediction of the vibration error which effects the precision of interferometer and it also can evaluate and select the algorithm of phase shifting.
The horizontal axis tilt of a theodolite is an important systematic error. In this paper, the horizontal axis tilt error of the theodolite was analysed, and the effect of the horizontal axis tilt on the measuring accuracy of theodolity was discussed. Then, the common detection method of horizontal axis tilt was introduced, and a new detection method based on the Leica theodolite was proposed according to the limitations of common methods. Experiments show that the new method has a good universality and can obtain the tilt directions of the theodolite easily based on Leica values. Finally, the measurement errors of two methods were compared, results show that the measuring error from new method is less than 4 because of Leica theodolite with excellent specifications, which is superior to that of common detection method.
According to the low precision and limited measuring range of a domestic independent-developed laser displacement sensor, a method which simulates the whole optical system using optical design software is proposed in this paper. Based on the analysis of each part's optical properties in the system, an optical system of laser displacement sensor with the measuring range of (5010) mm is designed to meet the practical requirement. With a separate approach, the whole optical system can be divided into two parts to be designed separately. The first part is a shaping lens of laser beam, which requires that the emerging spot is small and uniform in the effective working range. The result of design shows that the spot size can be controlled in the order of 10-1 mm. The other part designed is an imaging lens, which receives the scattered light from the measured surface. The properties of this part require that there is a certain angle between the planes of object and image and the optical axis. In the end, the designed results demonstrate that the images match Scheimpflug's condition.