Akira Ikegami
Hitachi
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Featured researches published by Akira Ikegami.
IEEE Transactions on Components, Hybrids, and Manufacturing Technology | 1987
Masayoshi Kaneyasu; Akira Ikegami; H. Arima; S. Iwanaga
An analytical method and experimental results of identifying and quantifying smells using an electronic system composed of an integrated sensor and a microcomputer are described. The integrated sensor with six different elements on an alumina substrate was fabricated by using thick-film techniques. The elements are kept at around 400°C by a Pt heater mounted on the sensor back. Since each element was made from different semiconductor oxides, they possess different sensitivities to material odors and the integrated sensor can develop specific patterns corresponding to each odor as a histogram of conductance ratios for each element. The microcomputer identifies the scent on the basis of similarities calculated by comparing standard patterns stored in the memory and a sample pattern developed by the integrated sensor. The scent is then quantified by using the sensor element with the highest sensitivity to the smell identified. The experimental results show that smells can be successfully identified and quantified with the electronic System.
IEEE Transactions on Components, Hybrids, and Manufacturing Technology | 1980
Akira Ikegami; H. Arima; H. Tosaki; Y. Matsuoka; Mitsuro Ai; H. Minorikawa; Y. Asahino
The electrical properties, reliability, and several successful applications of a thick-film thermistor are described. The thick-film thermistor is composed of a semiconducting oxide, precious metal (RuO 2 ), and glass. The resistivity and thermistor constant are affected to a great extent by the electrical properties of the semiconducting oxide, the particle size of RuO 2 , and the characteristics of the glass. The thermal expansion coefficient of the semiconducting oxide is required to be less than 105 x 10-7K-1in order to prevent the cracks in as-fired film. A resistivity ranging from I \Omega 2.cm to 10 M \Omega .cm together with a thermistor constant from 100 to 4500 K can be obtained by controlling these factors. These glass coated thick-film thermistors exhibit extremely high stability. An accelerated life test shows the drift rate as less than 0.02 percent/year in the resistance of a thick-film thermistor with a crystallized glass coating. A thick-film thermistor can be used widely as an accurate and stable temperature sensor and as an exact temperature compensating element in a thick-film hybrid circuit.
IEEE Transactions on Components, Hybrids, and Manufacturing Technology | 1989
Toshio Ogawa; Tadamichi Asai; O. Itoh; Mitsuru Hasegawa; Akira Ikegami; K. Atoh; T. Kobayashi
Key technologies for processing of a thick-film copper conductor applicable to photolithographic techniques are described. A flexo printer was used to obtain a film of less than 2- mu m thickness on a substrate. Using photolithographic techniques, fine-line circuits with 40- mu m-wide copper conductor lines were realized using copper pastes doped with chalcogens. Dense thin films and good adhesion to the substrate were achieved by doping chalcogens from 0.01 to 0.05 wt.%. Characteristics of these conductor films satisfied the standard requirements for hybrid ICs. >
IEEE Transactions on Components, Hybrids, and Manufacturing Technology | 1979
Katsuo Abe; Akira Ikegami; Nobuyuki Sugishita; Noriyuki Taguchi; Tokio Isogai; Ichiro Tsubokawa; Hiroshi Ohtsu
New dielectric pastes with high and low dielectric constants and an advanced passivation system have been developed for highly reliable capacitors and crossovers in thick-film circuit modules. Colloidal magnetite has been found to be a good sintering agent in BaTiO 3 -based high-K dielectric paste, and a crystallized low-K glass paste has been found to be suitable for small capacitors and crossovers. Alloyed Ag/Pd and Ag/PdO have been developed for conducting electrodes, which are compatible with the dielectric materials and the firing process. Physical defects are the critical factors in the glass passivation systems for the reliability because of possible moisture diffusion into the dielectrics. A new two-layered passivation system has been adopted. The capacitor system has been applied to an RF/IF thick-film hybrid module for radio-cassette recorders.
IEEE Transactions on Components, Hybrids, and Manufacturing Technology | 1988
Toshio Ogawa; Mituru Fujii; Tadamichi Asai; Akira Ikegami; T. Kobayashi
An assessment of a copper-conductor and resistor system and its performance in a high-frequency hybrid application is presented. Resistance of the copper compatible resistor, containing RuO/sub 2/, increases after refiring over 600 degrees C and drastically increases as the firing temperature is raised. Scanning-electron-microscope and energy-dispersive microprobe analyses revealed the existence of a RuO/sub 2/-poor area in the resistor adjacent to the copper terminals. The resistivity in this area is higher than that in areas removed from the terminals, and it increased with the refiring temperature. These facts indicate that the resistance change is caused by the diffusion of Ru to the copper conductor. Various approaches were taken to minimize this phenomenon. The most effective was insertion of a conductor pad between the copper conductor and resistor. Resistors with this type of Ag-Pd conductor pad meet the various requirements for practical application of hybrid ICs. Based on these results, a prototype, high-frequency hybrid IC (voltage-controlled oscillator, VCO) was fabricated. >
Active and Passive Electronic Components | 1981
Hideo Arima; Akira Ikegami; Hiromi Tosaki; Mitsuo Ai; Yoshitaka Matsuoka; Tsutomu Okayama
Thick film circuits were developed for temperature compensating of semiconductor strain gauges and for connecting the gauges to amplifiers in electronic pressure and differential pressure transmitters. In each circuit, ten Au pads for Al wire bonding and thirteen Ag/Pd pads for soldering must be fabricated on a small substrate. The results of the research are shown below.
Active and Passive Electronic Components | 1981
Akira Ikegami; Hideo Arima; Katsuo Abe
Descriptions are given of the fundamental dielectric properties of the thick film binary system, composed of dielectric powder and glass, in relation to the effect of bulk properties of the constituent electrode composition in preventing a decrease in breakdown voltage with time and the effect of glass passivation on the reliability of thick film capacitors.
Thin Solid Films | 1991
Osamu Ito; Tadamichi Asai; Toshio Ogawa; Mitsuro Hasegawa; Akira Ikegami; Yoshishige Endoh; Takeshi Araya; Kazuhiro Atoh; Takao Kobayashi
Abstract In order to obtain guidelines develop a thick film resistor (TFR) fireable in an N2 atmosphere and covering a wide practical range of sheet resistivities, i.e. 10–106 ω □ , the microstructures of TFRs were observed, the sintering behaviour of the conduction particles and glass was analysed and the particle size effect on the formation of the conduction path was simulated. Through these investigations, conductive material properties which influence the characteristics of the TFR have been found. (1) As conduction particles fireable in N2, LaB6 particles have suitable properties such as poor sinterability and good wettability with glass. (2) Particle size also has a large effect on the characteristics of the TFR, and it is necessary to use LaB6 ultrafine particles (UFPs) as conduction particles to cover a wide range of sheet resistivities. Using UFPs with specific surface areas of 8.9 and 83.0 m2 g−1, we found the possibility of developing TFRs fireable in N2 with resistivities of 10–106 ω □ in the LaB6-glass system.
Active and Passive Electronic Components | 1981
Nobuyuki Sugishita; Akira Ikegami; Tsuneo Endo
The results of a study into the fabrication of thick film multilayer devices which include resistors on and under the thick film dielectric layers are presented. Although the resistive values of the resistors under the dielectric change in the succeeding firing processes are influenced by the geometry of the resistors, the ratio of the resistivity change in resistors fabricated with the same sheet resistivity pastes and the same geometry is almost the same. The TCR of the resistors under dielectric layers is influenced mainly by the multi-firing processes. The resistive values and TCR of the resistors on dielectric layers are relatively uninfluenced by the dielectric. The stability of these resistors including trimmed ones under long-term thermal storage at 150℃ is compared with that of resistors on alumina substrates.
ieee/sice international symposium on system integration | 2016
Akihide Shibata; Akira Ikegami; Satomi Nakao; Sayaka Ishihara; Makoto Nakauma; Mitsuru Higashimori
This paper proposes a texture sensing system based on a biomimetic approach for nursing-care gel foods. The proposed system is equipped with an imitation tongue that can reproduce the elastic behavior of human tongue. First, we introduce the imitation tongue with a variable elasticity mechanism in the artificial mastication model. In this study, using a prototype of the imitation tongue, we verify that it can reproduce the elasticity of human tongue from the relaxed state to the contracted state. Then, we show that the pressure distribution in the artificial mastication of gel food changes clearly with respect to the elasticity of the imitation tongue. Finally, we develop the texture evaluation system that estimates the values of human sensory evaluation of the texture. We show that the texture can be accurately estimated with the appropriate elasticity of the imitation tongue.