In a design of optical multilayer films at oblique incidence, reflectance and transmittance curves for two planes of polarizations (S and P polarizations) are different, so a large number of layers are required more than at normal one. Therefore the design process will be more complex. We have already developed the optimum design system of optical multilayer films using a genetic algorithm. In this paper, the design of oblique incident coatings is considered. The mathematical optimization method is applied to find the local optimum solution. And it is described how to consider the constraints for the design of multilayer coatings. Several coatings for non-polarizing edge filters and multiple narrow band filters to oblique incidence are obtained successfully.

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An algorithm for calculating the minimum distance between non-convex polyhedra is described. A polyhedron is represented by a set of triangles. In calculating the distance between two polyhedra, it is important to search efficiently the pair of the triangles which gives the pair of closest points. In this paper discrete Voronoi regions are prepared as voxels around non-convex polyhedra. Each voxel is given a list of triangles which have possibility to be closest to the voxel. When a triangle on the other object is intersecting a voxel, the closest triangles can be efficiently searched from this list. The algorithm has been implemented, and the results of distance computations show that it can calculate the minimum distance between non-convex polyhedra composed of a thousand of triangles at interactive rates.

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This paper applies the method of robust design to machine tool design to propose a new design tool which can show some design suggestions at the early design stage. As a design evaluation example, the paper focuses on an ultra miniature that provides significant for energy and space saving. The approach combines an analytical procedure representing the machining motions of a machine tool (form-shaping theory) with procedures for robust design. The effort identifies the design parameters of a machine tool that significantly influence the machining tolerance and leads to general design guidelines for robust miniaturization. Further, this research applies the Taguchi method to the form-shaping function of a prototype miniature lathe. The analysis addresses five machine tool dimensions as control factors, while treating local errors in the machine structure as noise factors. The robustness study seeks to identify the importance of each factor in improving performance of the machine tool. The result shows that the design of the feed drive unit affects the performance most significantly. Among the local errors, straightness error of the same feed drive unit has a critical importance.

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This paper deals with the precise miniature robot which has been developed to perform surface clearing operation. The basic principle of this mechanism for precise locomotion is based on the combination of piezo elements and electromagnets for providing an inchworm manner. In order to capture such small objects on the surface, the unique capillary probe that the water in the tube can be pushed off by the magnetic piston and then the object can be taken in the water drop with the help of surface tension force was designed and fabricated. As a primaly experiment, it was confirmed that the capillary probe was successfully capable of capturing several small materials such as metal ball, particle and scraped paper. And the tiny robot with the capillary probe succeeded in capturing the small object on the surface and coveying it to the trash, and then throwing it away.

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Cut joint technique is employed in the first report for extension Rosenthal's order-n algorithm to multibody systems with closed-loop topology. Equations of motion and cut joint constraint equations constitute a set of differential-algebraic equation (DAE) that must be solved when doing dynamic analysis. When numerical method is employed for solving that DAE, cut joint constraint violation occurs. In this second report, methods for eliminating constraint violation are examined. The reliable approach for selecting parameters used in Baumgarte constraint stabilization method for variable step integration methods is proposed. Coordinate projection method is also proposed for constraint violation treatment. Dynamic analysis of a slider crank mechanism is carried out to show the validity of the proposed methods.

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Magnetic bearings can compensate spindle motion errors caused by unbalance and disturbance forces because of their active motion control capability. Moreover the magnetic bearings are free from friction and can be used in a vacuum so that they can be candidates for high accurate and high-speed bearings in the future. However few magnetic bearings of nanometer rotational accuracy have been reported. The goal of this research is to realize a magnetic bearing which has rotational accuracy of several manometers at a high speed. First, this paper introduces a precision magnetic bearing in which the radial two-degree-of-freedom motion of the spindle is controlled by electromagnets. Then a partial bias current control of the electromagnets is proposed to reduce heat generation of the electromagnets with high rotational accuracy. Finally experimental results show that the radial magnetic bearing using the partial bias current control can achieve the rotational accuracy of about 10nm (3σ) below 500min-1 without large heat generation.

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For high-speed and high-accuracy of aberration inspection process for pickup lens of optical head for digital versatile disc (DVD), an optical system based on shearing interference of spherical wavefront from pickup lens using grating has been applied. A simple algorithm, that processes points allocated on certain lines in fringe and fits relations between distance from basis point to the measurement points and phase difference at these points to equations of higher degree as curve fitting, has been devised. Coma, astigmatism and SA3 have been numerically estimated as the size of certain coefficient Inspection system based on this optical system and algorithm has been developed. Difference of measured value between the developed system and the conventional interferometer that has been treated as the standard is 3.9mλ and below at σ, this value is equal to difference between two conventional interferometers. Therefore accuracy of the developed system is equal to conventional interferometer. In comparison with the conventional spot system, this system has obtained higher accuracy, as well as 1/3 inspection time and 1/2 and under tact time.

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For higher definition and lower cost liquid crystal display, improvement of the mounting accuracy and productivity of liquid crystal driver IC in TCP (Tape Carrier Package) is essential.
In order to mount several TCP's, which previously have been mounted one by one, at one time, temperature-homogenous long bonding tool is needed. The FEM (Finite Element Method) has been used until now for the thermal analysis of the long bonding tool. However, there was a big difference between an analytical and measured values. In order to solve this problem, an FVM (Finite Volume Method) is used, in which ambient air flow and thermal effects on adjacent parts are taken into consideration for heat and flow analysis, for leading to temperature-homogenous of bonding tool.

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A new measuring method for particles of nanometer (nm)-order size on a Si (Silicon) wafer has been developed using a light-scattering method. In this method, a measuring system was developed to detect particles of nm-order size, by scanning the laser spot on the surface of a Si wafer. In this study, to improve the detection sensitivity for particle diameters, we attempted to discriminate detected voltage signals including the detected signal for particles and the measured noise signal for the surface of Si wafer on the photo multiplier tube (PMT). Consequently, the detection sensitivity was improved for particle diameters down to 15nm from 24nm. Results indicate that the detection sensitivity depends on the roughness of the measuring surface, and the maximum detectable diameter is theoretically determined to be 5nm. Furthermore, we attempted to measure a standard particle (polystyrene latex: PSL) adhering on the Si wafer surface, the particle diameter of which is known, using the developed measuring system and particle counting technique. As a result, it was verified that this system can measure particle diameters smaller than 80nm, which are difficult to detect using the particle counter. Moreover, to evaluate the developed measuring system, we attempted to measure particles on the surface of a bare Si wafer using this measuring system and the particle counter. Consequently, it was verified that this measuring system can detect particles of nm-order size on the Si wafer.

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It has been reported that, in the two joint motor link system of the human arm, complicate muscular alignments were simplified into three antagonistic pairs of six muscles including mono- and bi-articular muscles and these six muscle strengths were defined as functionally effective muscular strengths (FEMS), and the output force distribution exerted at the endpoint of the two-joint link system comes hexagonal shape, and further the six FEMS could be estimated based on the hexagonal characteristics of the output force distribution. In this study, it has been revealed that the same relationship between the output force distribution and the FEMS could be seen in the human leg as seen in the human arm, and the leg FEMS could be estimated with the ratio between the physiological cross sectional arias (PCSA) of the antagonistic biarticular leg muscles, because of its very little variation among the previous reports.

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Trochoidal sprocket for roller chain drive system has been developed which is used for a positioning mechanism. This system consists of a conventional roller chain and a pair of trochoidal sprockets. These sprockets are generated using trochoidal loci, which the tooth profile is shifted. Especially, the developed system can eliminate backlash In this report, the kinematical tooth profile conditions are analyzed. Also a prototype of a trochoidal sprocket is constructed using the optimal values and is tested for the positioning performance. It is proved that the positioning performance can be improved using the developed sprockets, compared with the case of using conventional one.

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A bilateral robot is one of the remote control robots. By implementing the force feed back, it is possible for the operator to have the sense of the touch. But the force sensor is affected by unknown disturbance such as its temperature variation and so on. For that reason, it is not expected to use the force sensor at the extreme situation. In the sensorless approach, the reaction torque observer is used. But the reaction observer is easy to be influenced of the friction. This makes it difficult to estimate the external force. To address the above issue, this article proposes a twin drive system. This system is composed of two motors and one differential mechanism. It is required to control two motors for two degrees of freedom. To consider the above issue, two virtual motors are proposed. One is deal with the output control and the other is for friction compensation. The twin drive system brings a sophisticated ability to the system, which is a reduction ability of the friction. By using this system, it is possible to realize the remote control robot, where the operator can feel the obstacle which the slave robot touches. This system may help the remote control work more skillfully. The validity of the proposed method is confirmed by the experimental results.

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This paper proposes a method to detect small optical defects, which distort light rays. In the method, a moving cyclic pattern illumination is applied and images of an object are captured continuously under different phase condition of the pattern illumination. Maximum signal and minimum signal between these images for each pixel are calculated. A maximum image consisted of maximum signals for each pixel is an image of bright field gathered from captured images under pattern illumination of various phase conditions. By the same token, a minimum image is an image under dark field. A pattern illumination provides high sensitivity of detection independent of places and information from multiple images provides high performance of recognition for inspection. The simple algorithm is not affected by image distortions of a pattern illumination, so it provides means to inspect curvature surface. Various internal low contrast defects of curvature glasses are inspected by the method using transmitted illumination, the results demonstrates that defects which is smaller than pixel resolution can be detected.

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For the purpose of applying electro-contact discharge dressing (ECDD) to a bronze-bonded diamond grinding wheel with fine grain size, single-pulse electric discharge experiments and the ECDD experiments utilizing a conductive resin bonded GC abrasive cup-wheel as the single electrode are carried out. From the results of the experiments, it is found that an electric discharge occurs when the electrode approaches the bronze bond at a distance of 3 to 5 μm. This means that the minimum grain size of the diamond grinding wheel applicable to the ECDD is limited to 6 to 10 μm. The utilization of water-soluble coolant causes a leakage current between the electrode and the grinding wheel so that the dry ECDD without a coolant should be applied in order to realize a satisfactory electric insulation. An open circuit voltage lower than the arc voltage of 20 V should be applied in order to maintain a constant discharge pulse frequency during ECDD. From the surface plunge grinding of aluminum oxide ceramics and an optical glass, it is found that the grinding wheel after ECDD gives a better finished surface roughness than that dressed by a GC abrasive cup wheel.

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In this paper, the activity of effective cutting grains in cutting of work and the activity of effective cutting grains in generation of finished surface are described. The former was investigated by the measurement of wheel surface temperature immediately after grinding using infrared radiation pyrometer with an optical fiber and the latter was investigated by the measurement of finished surface roughness using three-dimensional surface roughness tracer respectively. These activity of cutting grains in the whole circumference of wheel surface was clarified. The results obtained are as follows: 1) Cutting grains which have effective concern with cutting of work certainly act in every rotation of wheel. 2) The number of effective cutting grains in cutting of work increases as wheel depth of cut increases. 3) Cross-sectional shape of scratch toward grinding direction on the finished surface accurately correspond in the every period of one circumference of wheel in the order of sub-micrometer. 4) Finished surface is generated by some identical cutting grains even when wheel depth of cut increases.

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The study deals with five-axis control tool path generation for the sculptured surface machining with conicoid end mills. Ball end mills are in general utilized for the sculptured surface machining. However, it takes much time to finish such complicated surfaces with high accuracy due to the nessesity of a small amount of pick feed. Thus, a new cutting method is proposed to use special cutting tools, called conicoid end mill, for the sculputured surface machining. The study deals with the development of new CAM system with ellipsoid and hyperboloid end mills as well as paraboloid. From the experimental results, it is found that the conicoid end mills have the potential of reducing a machining time remarkably.

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The thermal stress cleaving of silicon wafer with a laser beam is a prospective technique, which supersedes the mechanical dicing. This method makes it possible to cut a wafer at very high production rate in comparison with the diamond thin blade wheel and to protect the wafer from the contamination of cutting coolant and chips. In this paper, the cleaving mechanism of silicon wafer irradiated with the pulsed Nd:YAG laser is investigated. The temperature at the area irradiated with laser is measured using two-color pyrometer with an optical fiber. The acoustic emission is also measured to examine the mechanism of the crack propagation. In the process, the temperature at the area irradiated with laser should be controlled in order to reduce the thermal damages and to improve the cleaving accuracy.

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Simultaneous irradiation of Ar ion is often employed to synthesize C-N films by ion-beam-assisted deposition. To clarify individual roles of N ion(reactive) and Ar ion(inert), films were prepared on Si(001) substrates, such as only C deposited (Carbon film), C evaporated in the atmosphere of 4×10^-2 Pa of N₂ (Carbon/N), C evaporated under the simultaneous irradiation of Ar ion (Carbon/Ar⁺), co-evaporated C and N (C-N), and co-evaporated C and N under the irradiation of Ar ion (C-N/Ar⁺). The differences of mechanical properties of the films are consistently explained in teens of chemical bonding manner as well as aligned structure. It is considered that the bombardment of N and Ar ions promotes two-dimensional network of chemical bonds forming the ordered stacking of graphite-like sheets and that the consequent columnar alignment perpendicular to the substrate surface is advantageous from the point of mechanical properties.

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Anew tool vibration system is developed for the ultrasonic elliptical vibration cutting, and it is applied to ultraprecision cutting of hardened steel in the present research. A method and a device to remove crosstalks between the two directional vibrations are developed, so that the two directional vibrations can be controlled independently. Then, a controller is developed to keep the elliptical vibration to have a desired locus, where the amplitudes of the two directional vibrations, phase shift between them are kept to be desired values and the vibration frequency is locked to an average of their resonant frequencies. The developed vibration control system is applied to utraprecision diamond turning of hardened steel, and an ultraprecise steel mirror with a shape accuracy of about 0.1 μm is achieved.

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A palm-top machine tool, "Micro-lathe", has been developed and evaluated. The machine tool sizes 32 x 28 x 30 mm in volume and weighs about 98 g. It uses a pair of micro-sliders as key components, orthogonally stacked as X and Z slides. On the top of the Z slide, a spindle unit and a 1.2 W DC drive motor are mounted, while a cutting tool is fixed on a base. Each micro-slider uses a unique step-feed configuration driven by two embedded PZT actuators. The complete micro-lathe system is numerically controlled by a full closed-loop feedback servo system using newly developed micro-linear encoders with 62.5nm resolution after 400X interpolation. A servo control of the two micro-slides is done by a separate controller based on a single board computer. Total occupying desktop space is about 550 x 450 mm, including the lathe, a custom NC and electronics. The system resolution is 0.2μm. No overshoot is induced due to the minimized moving mass, the settling time is only ruled by the maximum velocity. In terms of frequency response, 20Hz of bandwidth for 10μm amplitude was achieved. Using diamond tools complex shaft shapes of 2 mm maximum diameter can be practically machined. Surface roughness on a cylindrical surface was better than 50 nmRa, or 500 nmRz.

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Laser ablation process of aluminum with the fourth harmonics of Nd:YAG laser is simulated using the modified molecular dynamics, which has been developed previously by Ohmura and Fukumoto. Scattering velocities and their angles of ablation particles are visualized using vectors. Distribution and its transition of both scattering angles and velocities are investigated quantitatively. Transition of the number of ablation atoms and particles is also studied. The authors have already clarified that there are two types in laser ablation process. In this study, it is cleared that distribution of scattering angles and velocities of ablation particles depends on these ablation types. Transition of the number of ablation atoms and particles also depend on the ablation types. On the other hand, it is independent of the ablation types that the scattering angles have almost normal distribution and the number of particles increases little by little during the scattering process because large ablation particles are decomposed to smaller ones.

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