Gas and odor sensors have been used in various fields, for example detection of environmental pollution, safety and quality controls in the food industry and identification of various human behaviors in a residence. Many kinds of odors occur according to human behavior. The analysis of odor characteristics has been carried out. The main odors which occur in a residence are as follows: namely odors of meal preparation, excretion, perfume and body odors. Life patterns of an elderly person in solitude can be grasped roughly by analyzing the odor sensor characteristics. Taking meals and excretion are important vital actions to human beings. The actions can be known by identifying the odors.
This study attempts to identify a meal-degree, which means the kinds of meals taken, for example a light meal, a fried meal or a meal cooked by oneself. Various kinds of odor molecules occur at every meal and the sensor patterns vary. Meal-degree can be, therefore, understood by odor sensor patterns and it is also able to give the aged some suggestions about his health care according to long-term characteristics of plural odor sensors. As for the results, the number of responded sensors are few in a light meal and the sensor-grade is also small. In contrast with this matter, all of the installed sensors respond to fried or cooked meals, and the response grade is higher than a light meal.

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A micro urea sensor was fabricated using a micromachined Severinghaus-type ammonia gas-sensing electrode. The electrode detects a local pH change caused by the permeation of gaseous ammonia into the thin internal electrolyte layer in the sensitive area. An anodic iridium oxide film (AIROF) indicator electrode and a thin-film Ag/AgCl reference electrode were formed on a glass substrate by photolithography. The container for the electrolyte solution was formed by anisotropic etching of silicon. A through-hole was formed in one portion of the silicon container and a silicone rubber gas-permeable membrane was formed over the through-hole. Urease was immobilized on the gas-permeable membrane. Gaseous ammonia produced by the enzymatic reaction was detected by the ammonia gas-sensing electrode. Distinct response was observed, although the response was sluggish due to the low ammonia-permeability of the gas-permeable membrane. A linear relationship was obtained between the potential of the urea sensor and the logarithm of urea concentration between 5 and 50mM.

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A needle-type glucose sensor was microfabricated aiming for mass production of high-quality disposable biosensors. Integrated detecting electrode patterns including a novel thin-film Ag/AgCl reference electrode were formed on a glass substrate by photolithography. The novel thin-film Ag/AgCl reference electrode could maintain a potential expected as a Ag/AgCl electrode in 1M chloride solution for longer than 60h. A plasma-polymerized film was used as a supporting layer in immobilizing an enzyme (glucose oxidase) on the sensitive area. The film is extremely thin and its adhesion to the substrate is excellent. Because functional groups such as amino groups can easily be incorporated in its highly-crosslinked network structure, immobilization of an enzyme can be performed easily and effectively. The greatest advantage is that the process can enable mass production of high-quality biosensors at a low cost.

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A one-chip Ca²⁺ ion sensor integrated with a micro double junction Ag/AgCl reference electrode was microfablicated. The thin-film Ag/AgCl element used in the reference electrode features a polyimide protecting layer and the AgCl layer grown from a slit in the polyimide layer. The container for the internal KCl solution and a liquid-junction were formed with an SU-8 thick-film photoresist. KCl was incorporated in the micro container in a solid powdered form and the area was passivated with a silicone rubber. Another junction was formed at the end of the passivation. The double junction reference electrode could maintain a stable potential for approximately 80h. The Ca²⁺ ion-selective electrode was fabricated by forming an ion-selective membrane on one part of a silicon micro container formed by anisotropic etching. The one-chip Ca²⁺ ion sensor was constructed using the Ca²⁺ indicator electrode and the miniaturized liquid-junction reference electrode. A linear relationship was obtained between the indicator electrode potential and Ca²⁺ activity for Ca²⁺ activity higher than 10^-4. Sensitivity was 30.3mV/decade.

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The prototype model of the stacked CdZnTe semiconductor detector, which is able to measure the 6.13MeV γ-ray from ¹⁶N, was fabricated. The prototype's response calculation was carried out by Monte-Carlo method. The result of the response calculation agreed with the experiment data of check sources of ¹³⁷Cs and ⁶⁰Co, and ¹⁶N which was measured at vicinity of the primary cooling water pipe of the nuclear reactor. The source spectra were unfolded with detector's response function obtained by simulation, and it is indicated that the incident γ-ray energy and its intensity ratio was identified and that the energy of 6MeV γ-ray could be measured by the prototype of the stacked detector.

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A high-density full-color LED (light-emitting diode) display panel has been developed using LED array units which have many LED chips mounted on a silicon microreflector. The reflector is formed on a (100) silicon wafer by anisotropic chemical etching. The silicon microreflector absorbs the heat generated by the LED chips and improves their light-directive characteristics. The three types of LEDs (red, green and blue) in a unit are arranged in a matrix structure. Electric power to LED chips is supplied through side-wall wiring formed on the silicon microreflector substrate. This wiring structure allows the construction of a high-density LED display panel.

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Covalent immobilization of mucin molecules was carried out on a gold surface of surface plasmon resonance sensor. Interaction of three types of gastric ulcer drug with mucin was detected by measuring the shift of resonance angle. The two gastric proton pump inhibitors have shown drastic change, while antagonist of histamine H₂ receptor, showed insignificant change. The result suggests that SPR-based measurement is capable of evaluating binding capacity between an intestinal membrane and corresponding biosubstance, such as a gastric ulcer agent and mucin.

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