The photoelastic fringe pattern measurement technique is a nondestmctive method and is widely used to measure the mechanical-stress distribution inside solid materials. This distribution is evaluated by generating a photoelastic fringe pattern and counting the number of isocbromatic fringes (dark lines). If the amount of the mechanical-stress is very small, however, and the corresponding birefringence is smaller than π radians, no fringe lines are produced. This method is therefore not suitable when the amount of the mechanical stress is small. Furthermore, if the azimuth angle of the mechanical-stress is to be measured, the sample needs to be rotated. We therefore developed a highly sensitive measurement system suitable for measuring birefringence distributions smaller than π radians by using an electro-optical phase modulator (Pockets cell) and a two-dimensional lock-in amplifier system. This system can also at the same time measure the azimuth angle without rotating the sample. Here we report the principle of this two-dimensional measurement system and give the results of measuring the 2-D bireffingence distribution in a glass plate.

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A high-performance 801×512-element PtSi Schottky-barrier infrared image sensor has been developed with an enhanced Charge Sweep Device (CSD) readout architecture. In the enhanced CSD, the power consumption of the CSD has been reduced by employing a multiphase CSD with an on-chip multiphase CMOS clock generator. Flexible vertical scan is also possible using a newly developed transfer gate scanner. A large fill factor of 61% is obtained in spite of the small pixel size of 17×20μm². The differential temperature response and noise equivalent temperature difference with f/1.2 optics at 300K were 2.2×10⁴ electrons/K and 0.037K, respectively. The saturation signal level was 2.1×10⁶ electrons and the total power consumption of the device was less than 50mW.

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A newly developed technique for high voltage surface potential imaging having high resolution capability using Scanning Electrostatic Force Microscope(SEFM) is described. It can measure both electrostatic surface potential distribution of several hundred volts on the dielectric film and topography independently and simultaneously in high resolution of some tens of μm, in the air, quantitatively and without affecting charge distribution. The result of measuring surface potential distribution formed by spark discharge on a dielectric film is shown and compared to the results by a conventional electrostatic voltmeter and by toner method.

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We have developed a two-dimensional lock-in amplifier system which can detect very small changes in images and can be used to detect subsurface defects in polymer plates nondestructively. This system uses modulated lights to heat and to cool the polymer surfaces. If there is a defect in the subsurface, heat conduction is disturbed at the edges of the defect. The subsurface defect should be identified by the observation of the localized variant temperature variation region on the surface. The temperature distribution can be observed by using an infrared thermography, and the variation can be detected by using a two-dimensional lock-in amplifier system. This inexpensive measurement system should therefore be very useful in detecting small defects in various polymers, rapidly, nondestructively, and without any contact.

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A 16×16 monolithic pyroelectric infrared image sensor has been developed. The image sensor utilizes an electro-spray (ESP) deposited polyvinylidene fluoride (PVDF) thin film as a pyroelectric material, a buried channel MOSFET as a low noise detection device, and a micromachined four-beams supported membrane as a thermal isolation structure. A voltage sensitivity of 6600V/W and a detectivlty of 1.6×10⁷cmHz^1/2W^-1 have been realized with a sensing area of 75×75μm².

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Improvement in sensitivity performance of uncooled infrared sensor and increase in pixel numbers of the sensor have been accelerated. It is the first time in Japan that the uncooled camera is realized, which employs 256 ×256 uncooled bolometer sensor elements. Vanadium Oxide material is selected for the uncooled bolometer sensor whose element size is 50μm×50μm and formed on the diaphragm bridge structure.
As a result, it has a NETD of 0.2K for an f/1.0 lens at 30 frames per second.

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Electrical and piezoresistive properties of chemical-vapor-deposited boron-doped p-type polycrystalline diamond films were investigated. The p-type polycrystalline diamond films of about 2μm thickness were grown on a flat insulating polycrystalline diamond layer using a conventional microwave plasma CVD system. The p-type CVD diamond film exhibited similar quality as homoepitaxial single crystalline diamond film with activation energy of 0.31-0.33eV. Piezoresistor (500μm long and 50μm wide) constituted from the optimized p-type polycrystalline diamond films were fabricated on diaphragm structure using photolithography and reactive-ion etching in an oxygen plasma. Relative change of the electrical resistance (-ΔR/R₀) of the diamond piezoresistor was almost proportional to the apphed strain ε, Gauge factor K for the p-type diamond piezoresistor was derived to be about 1000 at room temperature and above 700 even at 473K.

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This paper reports a reduction of microvalve leakage according to precise measurements of the leak and flow rates. The tight contact between a valve cap and seat, which is obtained by nanometer-scale flat surfaces and by self-alignment of a cap and seat-bore, makes the leakage from a microvalve ultra-low. The leak and flow rates are determined by precisely measuring pressure changes when introducing helium gas into a flow line. We have, consequently, attained a leak rate as low as 5.8×10^-10Pa⋅m³/s and a flow rate ranging from 5.8×10^-10 to 3.2×10^-4Pa⋅m³/s.

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A fiber optic SPR sensor that combines surface plasmon resonance sensor with optical fiber is presented. The probe in this sensing system consists of a mirror and a sensing area where the surface plasmon is excited. Basically, the measurement principle of this sensor is the same as that of the prism SPR sensor. However, the excitation of surface plasmon is observed as a spectrum of a light that travels back and forth through the sensing area. First, the fundamental and optimal conditions of this sensor is presented from fundamental experimental results. And then, it is also shown to be possible to detect samples of different refractive indices. The applicability of this sensor is also discussed.

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We propose a bi-directional driving electrostatic actuator which has multiple parallel plate electrodes. The actuator generates a large force that is twice as much as the force of a conventional uni-directional driving actuator. In this paper, we describe the driving theory and its experimental verification. To verify the driving theory, a micro actuator is fabricated by a reactive ion etching process with an piece of SOI wafer. The experimental results on a voltage-displacement curve and a resonance agree with the theoretical calculation results. We also propose the modified driving method to increase the sensitivity around 0-displacement. According to this study, we can conclude that a bi-directional driving electrostatic actuator is very useful for driving optical switches, magnetic head elements of hard disk drives and so on.

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Aiming at the effective evaluation of the detectability of Eddy Current Testing(ECT) probes utilized in the nondestructive evaluation of Steam Generator(SG) tubing in Pressurized Water Reactor(PWR) type nuclear power plant, a new approach has been developed in this paper based on a simplified relation newly proposed for connecting induced eddy currents in SG tubing to the exciting magnetic field. To approximate the effect of the eddy current perturbation due to a small surface breaking crack, the ring current model has been improved to consider the crack opening through introducing a new set of ring currents. The proposed new model and simplified relation were validated by comparing eddy current distribution and the scattering magnetic field predicted by the present method and those calculated by an accurate numerical code. The applications to the S/N ratio analyses of several ECT probes and to the simulation of scan signals show this new method is feasible in the actual design and optimization of ECT probes.

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