• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.11
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• pp.46-54
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• 1998

A planar Bi-Sb multijunction thermal converter, which is consisted of a linear or bifilar thin film NiCr-heater and a thin film Bi-Sb thermopile, has been fabricated, and its ac-dc transfer characteristics were examined in a frequency range from 10 Hz to 10 KHz. In order to increase the thermal sensitivity and to decrease the ac-dc transfer error of a thermal converter, the heater and the hot junctions of a thermopile were prepared on a Si$_3$N$_4$/SiO$_2$/Si$_3$N$_4$-diaphragm which acts as a thermal isolation layer, and the cold junctions on the Si$_3$N$_4$/SiO$_2$/Si$_3$N$_4$-thin film supported with the silicon rim which functions as a heat sink. The respective thermal sensitivities in air and in a vacuum of the converter with a built-in bifilar heater were about 14.0 ㎷/㎽ and 54.0 ㎷/㎽, and the ac-dc voltage and the current transfer difference ranges in air were about $\pm$0.60 ppm and $\pm$0.11 ppm, respectively, indicating that the ac-dc transfer accuracy of the converter are much higher than that of a commercial 3-dimensional multijunction thermal converter. However, the output thermoelectric voltage fluctuation of the converter was rather high.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.212-212
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• 2009

Thermoelectric devices were used to wide range of application. At present, increasing the efficiency of these devices, in particular, through the preparation of materials showing a high thermoelectric figure of merit, Z, $Bi_2Te_3$ and $Sb_2Te_3$ thin films on Si substrates are deposited by flash evaporation method for thermopile sensor applications. In order to enhance the thermoelectric properties of the thin film, annealing in high vacuum is carried out in the temperature range from 200 to $350^{\circ}C$. The microstructure of the film is investigated by XRD and SEM. The resistivity and Seebeck coefficient of the films are measured by Van der Pauw method and hot probe method respectively. At elevating annealing temperature, the crystallinity and thermoelectrical properties of films are improved by increasing the size of grains. At excessive high annealing temperatures, it is shown that Seebeck coefficient of films is decreased because of Te evaporation. By optimizing the annealing conditions, it is possible to obtain a high performance thin film with a thermoelectric properties.

• Journal of Sensor Science and Technology
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• v.16 no.5
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• pp.331-336
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• 2007

In this study, we have fabricated an infrared optical fiber based sensor which can monitor the respiration of a patient. The design of a chalcogenide optical fiber based sensor is suitable for insertion into a high electro-magnetic field environment because the sensor consists of low cost and compact mid-infrared components such as an infrared light source, a chalcogenide optical fiber and a thermopile sensor. A fiber-optic respiration sensor is capable of detecting carbon dioxide ($CO_{2}$) in exhalation of a patient using the infrared absorption characteristics of carbon gases. The modulated infrared radiation due to the presence of carbon dioxide is guided to the thermopile sensor via a chalcogenide receiving fiber. It is expected that a mid-infrared fiber-optic respiration sensor which can be developed based on the results of this study would be highly suitable for respiration measurements of a patient during the procedure of an MRI.

• Journal of Sensor Science and Technology
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• v.17 no.6
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• pp.397-405
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• 2008

In this study, we have measured temperature distribution using infrared optical fibers during radiofrequency ablation (RFA). Infrared radiations generated from the water around inserted electrode are transferred by silver halide optical fibers and are measured by a thermopile sensor. Also, the output voltages of a thermopile sensor are compared with those of the thermocouple recorder. It is expected that a noncontact temperature sensor using an infrared optical fiber can be developed for the temperature monitoring during RFA treatments based on the results of this study.

• Restorative Dentistry and Endodontics
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• v.45 no.4
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• pp.55.1-55.12
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• 2020

Objectives: This study investigated the effects of physically damaged and resin-contaminated tips on radiant emittance, comparing them with new undamaged, non-contaminated tips using 3 pieces of spectrophotometric laboratory equipment. Materials and Methods: Nine tips with damage and/or resin contaminants from actual clinical situations were compared with a new tip without damage or contamination (control group). The radiant emittance was recorded using 3 spectrophotometric methods: a laboratory-grade thermopile, a laboratory-grade integrating sphere, and a portable light collector (checkMARC). Results: A significant difference between the laboratory-grade thermopile and the laboratory-grade integrating sphere was found when the radiant emittance values of the control or damaged/contaminated tips were investigated (p < 0.05), but both methods were comparable to checkMARC (p > 0.05). Regardless of the method used to quantify the light output, the mean radiant emittance values of the damaged/contaminated tips were significantly lower than those of the control (p < 0.05). The beam profile of the damaged/contaminated tips was less homogeneous than that of the control. Conclusions: Damaged/contaminated tips can reduce the radiant emittance output and the homogeneity of the beam, which may affect the energy delivered to composite restorations. The checkMARC spectrophotometer device can be used in dental offices, as it provided values close to those produced by a laboratory-grade integrated sphere spectrophotometer. Dentists should assess the radiant emittance of their light-curing units to ensure optimal curing in photoactivated, resin-based materials.

• 한국가스학회:학술대회논문집
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• 2006.11a
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• pp.123-128
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• 2006

This paper describes NDIR $CO_2$ gas sensor that shows the characteristics of temperature compensation. It consists of novel optical cavity that has two elliptical mirrors and a thermopile detector that includes ASIC chip in the same metal package for the amplification of detector output voltage and temperature sensor. The newly developed sensor modules shows high accuracy (less than +/-40 ppm) throughout the measuring concentration of $CO_2$ gas from 0 ppm to 2,000 ppm. After implementing the calculation methods of gas concentration, which is based upon the experimental results, the sensor module shows high accuracy less than +/- 5 ppm error throughout the measuring temperature range $(15^{\circ}C\;to\; 35^{\circ}C)$ and gas concentrations.

• Journal of Sensor Science and Technology
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• v.26 no.3
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• pp.168-172
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• 2017

A nondispersive infrared (NDIR) ethanol gas sensor was prototyped with ASIC implemented thermopile sensor, which included a temperature sensor and two ellipsoidal waveguide structures. The temperature dependency of the two ethanol sensors (with partially blocked and intact structures) has been characterized. The two ethanol gas sensors showed linear output voltages initially when varying the ambient temperature from 253 K to 333 K. The slope of the temperature sensor presented a constant value of 15 mV/K. After temperature compensation, the ethanol gas sensor estimated ethanol concentrations with larger errors of 20 to 25% below 200 ppm. However, the estimation errors were reduced to between -10 and +1 % from 253 K to 333 K above 200 ppm ethanol gas concentration in this research.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.1
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• pp.103-109
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• 2015

This paper introduces a multi-purpose smart fusion sensor. Normally, this type of sensor can contribute to energy savings specifically related to lighting and heating/air conditioning systems by detecting individuals in an office building. If a fire occurs, the sensor can provide information regarding the presence and location of residents in the building to a management center. The system consists of four sensors: a thermopile sensor for detecting heat energy, an ultrasonic sensor for measuring the distance of objects from the sensor, a fire detection sensor, and a passive infrared sensor for detecting temperature change. The system has a wireless communication module to provide the management center with control information for lighting and heating/air conditioning systems. We have also demonstrated the usefulness of the proposed system by applying it to a real environment.

• Journal of environmental and Sanitary engineering
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• v.10 no.2
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• pp.13-22
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• 1995

Most of small- scale livestock facility have difficulties to treat organic wastewater by activated sludge process as distinguished feces and urine. The organic wastewater discharged have characteristics of slurry, high concentration of BOD, 55 etc. This study was performed to estimate suitable condition for the application of packing materials, air flow, pollutant load and so on as important parameter to treat organic wastewater by thermopile oxlc process. As a result obtained at this experiments the most suitable condition for BOD load, air flow indicate 3.0kg · m$^{-3}$ day$^{-1}$,50 ∼ 100L· min$^{-1}$ m$^{-3}$, respectively, and we knew that it was necessary to add waste contained high calories to degrade about 80% of pollutant among waste- water. It showed that plastic material can be used as packing media because it can be provided as inhabitation for microorganism owing to intensity of material and characteristic of keeping moisture.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.226-231
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• 2000

New types of the micro heat flux sensor are designed and fabricated using SU-8 and Cu electroplating. And then calibrated under convection environment. The thermal path was made by SU-8 structure and electroplated Cu layers. The bottom surface of the micro heat flux sensor receives the heat flux from the wall, Then the heat flows along the Cu layers and drains out to the environment with producing the temperature difference at the upper layer of Cu. By measuring this temperature difference, the heat flux from the wall can be obtained. The temperature difference is measured by thermopile which is composed of Ni-Cr pairs or Al-chromel pairs. The calibration is accomplished under convection environment because it is most frequent situation. The range of the sensitivity is 0.11~2.02$\mu$V/(㎽/$\textrm{cm}^2$) for the various heat flux and Reynolds numbers.