Odor recorder, where an odor with its recipe electronically recorded is reproduced by an odor blender, was developed. The odor recipe can be determined within a minute by the active odor sensing system with a QCM gas sensor array and an internal blender. The odor recipe can be obtained after minimizing the difference between the sensor-array output pattern of the target odor and that of the internally blended one using multiple-input multiple-output feedback control. The recipe of an apple flavor made up of four component odors with the impressions such as softly green note, sour sweet, fruity and the smell of grass was successfully determined by the system. Furthermore, it was confirmed that the odor the same as the target odor was reproduced using the internal odor blender. The principle and the fundamental experiments on odor recording are presented here.

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We report the development of high sensitive Quartz Crystal Microphone using micro machining technology. The purpose of the microphone is to apply it as a sensor in gas analysis system. Moving part and gap of Quartz Crystal Microphone are manufactured by anisotropic etching and electro plating technology. It's sensitivity and anti vibration characteristics have been greatly improved compare with conventional microphones.

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An electrostatically driven surface output optical switching device with a sheet waveguide is proposed. The device mainly consists of two optical parts, that is an optical glass substrate to propagate the incident light and an electrostatic movable Ta₂O₅ cantilever to transfer light energy from the substrate to free space. When the voltage is applied, the cantilever is attracted and contacts to the substrate. By the contact, light energy transfered from the substrate to the cantilever is scattered by the diffusive surface on the Ta₂O₅ cantilever resulting in the optical switching. The device is fabricated by using micro-machine techniques to demonstrate the principle. A diffusive surface on the cantilever is fabricated by an RIE etching. Switching operations are demonstrated. As a result, modulated light amplitudes are observed from diffusive surface on the cantilever according to the voltage change. A switching contrast of 0.75 and an extinction ratio of 8dB are obtained at a driving frequency of 60Hz. It is shown that the device can be usefulness for optical switching. Also, it is considered that the device can be applied to a display device when the device is integrated on the substrate.

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A multichannel taste sensor using lipid/polymer membranes has higher sensitivities to electrolytes such as sour and salty substances than nonelectrolytes such as sweet substances. The purpose of this study is to improve sensitivity to sweet taste substances. The response to sweetness is assumed to have a mechanism different from electrolytic taste substances due to its nonelectrolyte. We could make large improvement of the response to sweetness by mixing positively and negatively charged lipid/polymer membranes and utilizing their hydrophobic property.

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A new technique to control selectivity of mask materials during XeF₂ etching was proposed. By exposing Si sample with SiO₂ and Si₃N₄ as mask materials to UV light of 981mW/cm² during XeF₂ etching, the etching rate ratios of Si/SiO₂ and Si/Si₃N₄ were dramatically decreased from 11446 to 906.1 and from 488.2 to 29.3, respectively. This new technique allows us to remove the mask material selectively and change the mask pattern by UV light exposure during in-situ etching process without additional photolithography step and opens a new silicon micromachining process for 3-dimensional fabrication. The multi-step Si structure was successfully realized by this technique.

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