• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.2
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• pp.186-191
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• 2017

An integrated pressure-sensor system was developed using the sensor-conditioning processes, which resulted in the optimum sensitivity of the pressure-sensor through the signal amplification, noise reduction, and level shift. Due to the specified characteristics among the components, such as operation range, the sensor output was generally limited compared to the full scale of the reading when coupled with other parts. Devices fabricated exhibited comparable characteristics with higher pressure sensitivity to that of the pressure sensor without sensor-conditioning process. In this work, the sensor resolution was at least enhanced at least by 25% using the sensor-conditioning processes.

• Journal of Mechanical Science and Technology
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• v.20 no.4
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• pp.505-512
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• 2006

This paper presents an integrated multifunctional sensor based on MEMS technology, which can be used or embedded in mobile devices for environmental monitoring. An absolute pressure sensor, a temperature sensor and a humidity sensor are integrated in one silicon chip of which the size is $5mm\times5mm$. The pressure sensor uses a bulk-micromachined diaphragm structure with the piezoresistors. For temperature sensing, a silicon temperature sensor based on the spreading-resistance principle is designed and fabricated. The humidity sensor is a capacitive humidity sensor which has the polyimide film and interdigitated capacitance electrodes. The different piezoresistive orientation is used for the pressure and temperature sensor to avoid the interference between sensors. Each sensor shows good sensor characteristics except for the humidity sensor. However, the linearity and hysteresis of the humidity sensor can be improved by selecting the proper polymer materials and structures.

• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.141-147
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• 2017

A pressure sensor in pulse measurement system is a core component for precisely measuring the pulse waveform of radial artery. A pulse sensor signal that measures the pulse wave in contact with the skin is affected by the temperature difference between the ambient temperature and skin surface. In this study, we found experimentally that the signal changes of the pressure sensors and a temperature sensor were caused by the temperature of the wrist surface while the pressure sensor was contacted on the skin surface for measuring pulse wave. To observe the signal change of the pulse sensor caused by temperature increase on sensor surface, Peltier device that can be kept at a set temperature was used. As the temperature of Peltier device was kept at $35^{\circ}C$ (the maximum wrist temperature), the device was put on the pulse sensor surface. The temperature and pressure signals were obtained simultaneously from a temperature sensor and six pressure sensors embedded in the pulse sensor. As a result of signal analysis, the sensor pressure was decreased during temperature increase of pulse sensor surface. In addition, the signal difference ratio of pressure and temperature sensors with respect to thickness of cover layer in pulse sensor was increased exponentially. Therefore, the signal of pressure sensor was modified by the compensation equation derived by the temperature sensor signal. We suggested that the thickness of cover layer in pulse sensor should be designed considering the skin surface temperature.

• Journal of Sensor Science and Technology
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• v.22 no.3
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• pp.227-232
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• 2013

In this research, fiber-optic pressure sensors were fabricated with rugate-structured porous silicon (RPS) diaphragms coated with PMMA (Polymethyl-Methacrylate). The reflectance spectrum of the PMMA/RPS diaphragm was almost the same as that of uncoated RPS diaphragm. However the mechanical strength of the PMMA/RPS diaphragm increased more than that of the uncoated diaphragm. As a result, the fiber-optic sensor fabricated with PMMA/RPS diaphragm could successfully detect more high pressure difference without diaphragm damage than the highest detectable pressure difference of the sensor with normal RPS diaphragm. The response data of the fiber-optic sensor recorded as a function of pressure difference were fitted by theoretical curves. During this process, elastic moduli of the used PMMA/RPS diaphragms were obtained numerically. The dynamic response properties of the fiber-optic sensor were also investigated under continuous variation of the pressure difference conditions.

• Journal of Sensor Science and Technology
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• v.14 no.4
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• pp.265-271
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• 2005

In this study, a variable capacitive pressure sensor is fabricated for TPMS (Tire Pressure Monitoring System). This study is for developing sensors which consecutively measure the tire pressure given as 30 psi from the industrial standard. For improving non-linearity of the prior capacitive pressure sensors, it is suggested that touch mode capacitive pressure sensor be applied. In addition, initial capacitance is designed as small as possible for the conformity to the wireless sensor. ANSYS, commercial FEA package, is used for designing and simulating the sensor. The device is progressed by MEMS (Micro Electro Mechanical Systems) fabrication and packaged with PDMS. The result is obtained sensitivity, 1 pF/psi, through a pressure test. The simulation result is discrepant from experiment one. Wafer's uniformity is presumed as the main reason of discrepancy.

• Journal of the Semiconductor & Display Technology
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• v.17 no.4
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• pp.76-79
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• 2018

In this paper, we developed a pressure monitoring system using silicon pressure sensor. The pressure monitoring system was developed on the basis of a microcontroller, and a self-developed silicon pressure sensor was applied. The pressure monitoring system outputs the current pressure value via UART communication. In addition, it includes a function of displaying by LED when the preset three-step pressure (low, medium, high pressure) is reached. The silicon pressure sensor used in the pressure monitoring system was set to 0 kPa, 10 kPa, 26 kPa, and the pressure monitoring system was evaluated because the measured maximum pressure was in the range of 100 kPa.

• Journal of Sensor Science and Technology
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• v.26 no.1
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• pp.24-27
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• 2017

In this study, I developed a simple and low cost process-printing a silver, carbon, dielectric, adhesive layer on PET films using screen printing technology and bonding the two films face-to-face-to fabricate a low price capacitive pressure-mapping sensor. Both electrodes forming the pressure measuring capacitor are arranged between the two PET films similar to a sandwich. Therefore, the sensor has the advantage of minimizing the influence of external noise. In this study, a $10{\times}10$ capacitance-type pressure-mapping sensor was fabricated and its characteristics were analyzed.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.51-56
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• 2017

In this paper, we have developed a differential pressure flow sensor designed as a single capacitive type. And the sensor was fabricated using a MEMS process. Differential pressure flow sensors are the most commonly used sensors for industrial applications. The sensing diaphragm and bonding joint of the MEMS pressure sensor are easily broken at high pressure. In this paper, we proposed a structure in which the diaphragm of the sensor was not broken at a pressure exceeding the proof pressure, and the differential pressure sensor was designed and manufactured accordingly. The operating characteristics of the sensor were evaluated at a pressure three times higher than the sensor operating pressure (0-3 bar). The developed sensor was $3.0{\times}3.0mm$ and measured with a LCR meter (HP 4284a) at a pressure between 0 and 3 bar. It showed 3.67 pF at 0 bar and 5.13 pF at 3 bar. The sensor operating pressure (0-3 bar) developed a pressure sensor with hysteresis of 0.37%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.1
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• pp.23-29
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• 2016

In this paper, in order to quantify the peristalsis occurrence in a guinea pig's large intestine, a miniaturized air-gap capacitive pressure sensor was fabricated through micro-electro-mechanical system (MEMS). The proposed pressure sensor is a two-layered biocompatible polyimide substrate consisting of an air-gap capacitive plates between the substrates. The proposed pressure sensor was designed with a careful consideration of the structure and motility mechanism of the guinea pig's large intestine. Artificial pellets were mounted on a prototype pressure sensor to provide some redundancies in the form of size and shape of the guinea pig feces. Capacitance of a prototype sensor was recorded to be 2.5 ~ 3 pF. This capacitance value was later converted to count value using a lab fabricated data conversion system. Sensitivity of the pressure sensor was recorded to be below 1 mmHg per atmospheric pressure. During in vivo testing, artificial peristalsis caused by drug injection was measured by inserting the prototype pressure sensor into the guinea pig's large intestine and pressure data obtained due to artificial peristalsis was graphed using a labview program. The proposed pressure sensor could measure the pressure changes in the proximal, medial, and distal parts of the large intestine. The results of the experiment confirmed that pressure changes of guinea pig's large intestine was proportional to the degree of drug injection.