• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.464-467
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• 2007

All image data acquisition systems for example the digital camera and digital camcorder, use the image sensor to convert the image data (light) into electronic data. These image sensors are used in satellite camera for high quality and resolution image data. There are two kinds of image sensors, the one is the CCD (charge coupled device) detector sensor and the other is the CMOS (complementary metal-oxide semiconductor) image sensor. The CCD sensor control system has more complex than the CMOS sensor control system. For the high quality image data on CCD sensor, the precise timing control signal and the several voltage sources are needed in the control system. In this paper, the comparison of the CCD with CMOS sensor, the CCD sensor characteristic, and the control system will be described.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.385-386
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• 2008

Reducing the PR(Photoresist) dispense Rate is one of the important issues in Photolithography. It is a main concern that variation in PR dispense rate and existance of microbubble. so we need to measure the photoresist dispense rate more precisely. This paper presented a noble sensor of measuring the PR dispense and detecting the microbubble.

• Journal of the Semiconductor & Display Technology
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• v.14 no.2
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• pp.17-22
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• 2015

In recent years, wireless sensor networks have become an important part of data communications. Sensors provide information about the required measurements or control states over wireless networks. The energy efficient routing protocol of wireless sensor networks is the key issue for network lifetimes. The routing protocol must ensure that connectivity in a network is remained for a long period of time and the energy status of the sensor in the entire network must be in the same level in order not to leave the network with a wide difference in the energy consumptions of the sensors. In this paper we propose a new routing protocol based on AODV protocol that considers the energy efficiency when the protocol determines the routing paths, which is called AODV-EE. The proposed method prevents an imbalance of power consumption in sensors of wireless networks. From the simulation results it is shown that the proposed algorithm can be effectively used in collecting and monitoring data without concerning about the disconnection of the networks.

• Journal of Sensor Science and Technology
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• v.1 no.2
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• pp.101-106
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• 1992

pH-ISFETs, the semiconductor pH sensors, were combined with immobilized enzyme membranes to prepare FET type urea and glucose sensors and its operational characteristics were investigated. Photolithography techniques were applied to immobilize enzymes on the $H^{+}$ sensing membrane of the pH-ISFET with photo-sensitive polymers, PVA-SbQ. Fabricated urea and glucose sensors could determine $0.5{\sim}50{\;}mg/dl$ urea concentrations and $10{\sim}1000{\;}mg/dl$ glucose concentrations, respectively.

• Journal of information and communication convergence engineering
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• v.4 no.1
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• pp.18-22
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• 2006

A small-sized gas identification system has been fabricated and characterized using an integrated gas sensor array and artificial neural-network. The sensor array consists of four thick-film oxide semiconductor gas sensors whose sensing layers are $In_{2}O_{3}-Sb_{2}O_{5}-Pd-doped\;SnO_2$ + Pd-coated layer, $La_{2}O_{5}-PdCl_{2}-doped\;SnO_2,\;WO_{3}-doped\;SnO_{2}$ + Pt-coated layer and $ThO_{2}-V_{2}O_{5}-PdCl_{2}\;doped\;SnO_{2}$. The small-sized gas identification instrument is composed of a GMS 81504 containing an internal ROM (4k bytes), a RAM (128 bytes) and four-channel AD converter as MPU, LEDs for displaying alarm conditions for three gases (liquefied petroleum gas: LPG, liquefied natural gas: LNG and carbon monoxide: CO) and interface circuits for them. The instrument has been used to identify alarm conditions for three gases among the real circumstances and the identification has been successfully demonstrated.

• Transactions on Semiconductor Engineering
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• v.1 no.1
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• pp.9-13
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• 2023

An AlGaN/GaN heterojunction-based hydrogen sensor with SnO₂ nanoparticles/Pd catalyst layer was fabricated for room-temperature hydrogen detection. The fabricated sensor exhibited unstable drift in standby current when it was operated at room temperature. The instability in the sensing signal was dramatically improved when the sensor was operated under UV illumination.

• Transactions on Semiconductor Engineering
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• v.2 no.1
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• pp.9-16
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• 2024

This paper discusses the design of bio-implanted ultra-low-power MICS RF transceivers for wireless sensor networks. The 400 MHz MICS standard was considered for the implementation of the WBAN wireless sensor system, indirectly minimizing radio propagation losses in the human body and the inference with surrounding networks. This paper includes link budget, various transmission and reception architectures for a system design and ultra-low power transceiver circuit techniques for the implementation of RF transceivers that meet MICS standards.

• Transactions on Semiconductor Engineering
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• v.2 no.2
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• pp.10-14
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• 2024

This paper presents a circuit design aimed at generating the required reference voltage and temperature sensor voltage in conjunction with an ADC, utilizing the current generated by temperature characteristics of BJT components for sensor data conversion. Additionally, two control methods are introduced to reduce the standard deviation of the circuit, resulting in over a ten-fold decrease in standard deviation. The proposed circuit occupies an area of 0.057mm² and was implemented using 55nm RF process.

• Korean Journal of Optics and Photonics
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• v.32 no.2
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• pp.79-85
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• 2021

In this paper, a study is conducted on the design of an optical system of a time-of-flight (TOF) laser distance sensor that can measure long distances by minimizing beam divergence. When measuring a long distance, the amount of light on the object's surface decreases as the distance increases, due to the diffusion angle of the laser beam, and thus the beam at the sensor also decreases, causing measurement errors. In general, a cylindrical lens is used to reduce the divergence beam angle. However, an optical system using a cylindrical lens has the problem of degraded performance due to the difficulty with assembly tolerance, as well as the problem of the increased size of the optical system, and thus the use of aspherical lenses has been increasing recently. Therefore, in this study, the optical efficiencies and assembly tolerances of optical systems using respectively a cylindrical lens and an aspherical lens are compared and analyzed.

• Transactions on Electrical and Electronic Materials
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• v.11 no.1
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• pp.24-28
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• 2010

A simulation study of a current-mode direct current (DC)-DC buck converter is presented in this paper. The converter, with a fully integrated power module, is implemented by using sense method metal-oxide-semiconductor field-effect transistor (MOSFET) and bipolar complementary metal-oxide-semiconductor (BiCMOS) technology. When the MOSFET is used in a current sensor, the sensed inductor current with an internal ramp signal can be used for feedback control. In addition, the BiCMOS technology is applied in the converter for an accurate current sensing and a low power consumption. The DC-DC converter is designed using the standard $0.35\;{\mu}m$ CMOS process. An off-chip LC filter is designed with an inductance of 1 mH and a capacitance of 12.5 nF. The simulation results show that the error between the sensing signal and the inductor current can be controlled to be within 3%. The characteristics of the error amplification and output ripple are much improved, as compared to converters using conventional CMOS circuits.