Optics for encoders is studied from the point of view of signal improvement and miniaturization. Basis of optical encoder is the superposition of two gratings. Moire encoder consisting of two superimposed gratings is simple but the encoder signal is often affected by the variation of air gap due to the Fourier image effect. In this paper, basic optics of the encoders is summarized and some advanced optics for the Moire encoders are explained to suppress the influence.

View full abstract

We have developed high-sensitivity in-situ measurement technology based on photons with visible to ultraviolet wavelength bands. This measurement technology builds on plasmatizing particles technology and a high-sensitivity measurement technology for measuring photons from the plasma. Thus, we have established a technology for measuring particle sizes and the constituent element content of particles with 10% accuracy.

View full abstract

We have proposed the new multi-functional sensor by using optical branching circuit with loop waveguide. The optical branching circuit consisted of cylindrical and planar slab waveguides fabricated by the ion-exchange process in Pyrex glasses. We discuss the feasibility of the optical branching circuit with loop waveguide from the several essential aspects experimentally such as ion-exchange time, coupling length of branch and refractive index of matching liquid. These experimental results demonstrate that the multi-functional sensor by using the optical branching circuit with loop waveguide has compactness and good sensitivity as compared with the conventional sensors by slab waveguides.

View full abstract

This paper describes the development of a highly sensitive Ni foil temperature sensor. The element structure of the Ni foil temperature sensor is constructed from Ni foil with approx.3 μm in thickness bonded on to crystallized glass with epoxy resin and measures just 0.7×8.0×0.3 mm, yet its resistance value is 1 kΩ. A fine pattern is fabricated in the Ni foil using photo etching technology. The size of the sensing part of the stainless steel protective tube, which houses the Ni sensing element, is a mere, Φ1×30 mm. Optimal conditions for the main manufacturing processes of the sensor were determined by examining the crystal structure and stress on the Ni foil using an X-ray diffractometer, X-ray stress analyzer and SEM. Ni temperature sensors fabricated using these optimal conditions exhibited high sensitivity and stable performance. TCR is 6600ppm/°C between 0°C and 100°C, the same as pure Ni wire, and is stable at room temperature with a drift of ±0.005°C/year. After calibration this temperature sensor is highly accurate with a fast thermal response time. Therefore the Ni foil temperature sensor is applied to precision manufacturing, semiconductor and other industries where high accuracy is demanded.

View full abstract