• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.209-212
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• 2001

A flame detector responds either to radiant energy visible to the human eye or outside the range of human vision. Such a detector is sensitive to glowing embers, coals, or flames which radiate energy of sufficient intensity and spectral quality to actuate the alarm. An infra-red detectors can respond to the total IR component of the flame alone or in combination with flame flicker in the frequency range of 5 to 30 Hz. A major problem in the use of infrared detectors receiving total IR radiation is the possible interference of solar radiation in the infrared region. When detectors are located in places shielded from the sun, such as vaults, filtering or shielding the unit from the sun's rays is unnecessary. In this study, we proposed method for redue a false alarm with using filtering & sensor technology for distinguish of causes of raise a false alarm and pure flame.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.11
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• pp.52-62
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• 1995

We developed a two-dimensional numerical simulator which can analyze the electrical as well as optical characteristics and evaluate the detection performances of self-signal processing infrared detectors. It solves the poisson equation and the electron, hole current continuity equations including the optical generation and recombination models. To speed up convergency rate. the Newton algorithm is used. Automatic triangular grid generator make it easy to simulate the devices with the various read-out geometries. This simulator can show the variation of spatial resolution which is caused by the transit velocity and transit time dispersion in bifurcate and horn geometries respectively. Also, we calculated the responsivity, noise, and detectivity in respect of the applied electric field and background field-of-view. The results obtained from simulation correspond to those of experiments, and it is verified that horn read-out geometry has the superior spatial resolution and detection performance to bifurcate geometry.

• Fire Protection Technology
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• s.13
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• pp.18-26
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• 1992

This report is explained about operating principles, characteristices of flame detectors. Flame detector is designed to detect the UV (Ultraviolet) and IR (Infrared) rediation produced by flaming involving carbonaceous materials.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.4
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• pp.93-100
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• 1998

Pyoelectric infrared detectors based on La-modified PbTiO3 (PLT) thin films have been fabricated by RF magnetron sputtering and micromachining technology. The detectors form Pb$_{1-x}$ La$_{x}$Ti$_{1-x}$ O$_{3}$ (x=0.05) thin film ferroelectric capacitors epitaxially grown by RF magnetron sputtering on Pt/MgO (100) substrate. The sputtered PLT thin film exhibits highly c-axis oriented crystal struture that no poling trealization for sensing applications is required. This is an essential factor to increase the yield for realization of an infrared image sensor. Micromachining technology is used to lower the thermal mass of the detector by giving maximum sensor efficiency. Polyimide is coated on top of the sensing elements to support the fragile structure and the backside of the MgO substrate is selectively eteched to reduce the heat loss. The sensing element exhibited a very high detectivity D* of 8.5*10$^{8}$ cm..root.Hz/W at room temperature and it is about 100 times higher than the case of micromachining technology is not used. a sensing system that detects the position as well as the existence of a human body is realized using the array sensor.sor.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.128.2-128.2
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• 2014

Long-wave infrared detectors using the type-II InAs/GaSb strained superlattice (T2SL) material system with the nBn structure were designed and fabricated. The band gap energy of the T2SL material was calculated as a function of the thickness of the InAs and GaSb layers by the Kronig-Penney model. Growth of the barrier material (Al0.2Ga0.8Sb) incorporated Te doping to reduce the dark current. The full width at half maximum (FWHM) of the 1st satellite superlattice peak from the X-ray diffraction was around 45 arc sec. The cutoff wavelength of the fabricated device was ${\sim}10.2{\mu}m$ (0.12eV) at 80 K while under an applied bias of -1.4V. The measured activation energy of the device was ~0.128 eV. The dark current density was shown to be $1.2{\times}10^{-5}A/cm^2$ at 80 K and with a bias -1.4 V. The responsivity was 1.9 A/W at $7.5{\mu}m$ at 80K and with a bias of -1.9V.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.365-370
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• 2005

Infrared (lR) detectors are widely used for such applications as thermoelstic stress analysis, medical diagnostics and temperature measurement. Infrared detectors commonly need to be refrigerated below 80 K, and thus a cooling system should be equipped together with the detector system. The cooling load, which should be removed by the cooling system to maintain the nominal operating temperature of the detector, critically depends on the insulation efficiency of the cryochamber housing the detector. Cryochamber considers the conduction heat transfer through a cold finger, the gases conduction and radiation heat transfer. The thermal loads of an infrared detector Cryochamber with radiation shield are investigated experimentally in present study. Since the effect of radiation heat transfer on thermal loads is significant, radiation shields is installed in the cold finger part to protect heat input through radiation. It is found that the thermal load can be substantially reduced by increasing the number of radiation shield.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.11
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• pp.1005-1009
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• 2008

A noble infrared $\lambda/4$ absorbing structure using metal reflector was studied for uncooled infrared sensors. This paper described the design and the fabrication of IR uncooled detectors which were composed of 21 by 21 elements using the surface micromachining technology. The characteristics of the array were investigated in the spectral region of 4.26 ${\mu}m$. The fabricated detectors exhibited the thermal mass of $9.75\times10^{-9}$ J/K, the thermal conductance of $1.31\times10^{-6}$ W/K, the thermal time constant of 7.4 ms, the responsivity of $1.07\times10^5$ V/W and the detectivity of $1.04\times10^9$ $cmHz^{1/2}/W$, at the chopper frequency of 10 Hz and the bias current of 9.22${\mu}A$. Finally the absorptance efficiency of $\lambda/4$ absorbing structure was about 23.2 % higher than that of absence absorbing structure.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.10
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• pp.889-894
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• 2004

Infrared (IR) detectors are widely used for many applications, such as temperature measurement, intruder and fire detection, robotics and industrial equipment, thermoelstic stress analysis, medical diagnostics, and chemical analysis. Quantum detectors commonly need to be refrigerated below 80 K, and thus a cooling system should be equipped together with the detector system. The cooling load, which should be removed by the cooling system to maintain the nominal operating temperature of the detector, critically depends on the insulation efficiency of the cryochamber housing the detector. Thermal analysis of cryochamber includes the conduction heat transfer through a cold well, the gases conduction and gas outgassing, as well as radiation heat transfer, The transient cooling characteristics of an infrared detector cryochamber are investigated experimentally in the present study. The transient cooling load increases as the gas pressure is increased. Gas pressure becomes significant as the cooling process proceeds. Cool down time is also increased as the gas pressure is increased. It is also found that natural convection effects on cool down time become significant when the gas pressure is increased.

• Journal of Electrical Engineering and information Science
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• v.3 no.2
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• pp.239-244
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• 1998

Piezoelectric pressure sensors and pyroelectric infrared detectors based on ZnO thin film have been integrated with GaAs metal-semiconductor field effect transistor (MESFET) amplifiers. Surface micromachining techniques have been applied in a GaAs MESFET process to form both microsensors and electronic circuits. The on-chip integration of microsensors such as pressure sensors and infrared detectors with GaAs integrated circuits is attractive because of the higher operating temperature up to 200 oC for GaAs devices compared to 125 oC for silicon devices and radiation hardness for infrared imaging applications. The microsensors incorporate a 1${\mu}$m-thick sputtered ZnO capacitor supported by a 2${\mu}$m-thick aluminum membrane formed on a semi-insulating GaAs substrate. The piezoelectric pressure sensor of an area 80${\times}$80 ${\mu}$m2 designed for use as a miniature microphone exhibits 2.99${\mu}$V/${\mu}$ bar sensitivity at 400Hz. The voltage responsivity and the detectivity of a single infrared detector of an area 80${\times}$80 $\mu\textrm{m}$2 is 700 V/W and 6${\times}$108cm$.$ Hz/W at 10Hz respectively, and the time constant of the sensor with the amplifying circuit is 53 ms. Circuits using 4${\mu}$m-gate GaAs MESFETs are fabricated in planar, direct ion-implanted process. The measured transconductance of a 4${\mu}$m-gate GaAs MESFET is 25.6 mS/mm and 12.4 mS/mm at 27 oC and 200oC, respectively. A differential amplifier whose voltage gain in 33.7 dB using 4${\mu}$m gate GaAs MESFETs is fabricated for high selectivity to the physical variable being sensed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.4
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• pp.34-38
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• 2005

This is a widespread requirement for low cost lightweight thermal imaging sensors for both military and civilian applications. Today, a large number of uncooled infrared detector developments are under progress due to the availability of silicon technology that enables realization of low cost IR sensor. System prices are continuing to drop, and swelling production volume will soon drive process substantially lower. The feasibility of micromechanical optical and infrared (IR) detection using microcantilevers is demonstrated. Microcantilevers provide a simple Structurefor developing single- and multi-element sensors for visible and infrared radiation that are smaller, more sensitive and lower in cost than quantum or thermal detectors. Microcantilevers coated with a heat absorbing layer undergo bending due to the differential stress originating from the bimetallic effect. This paper reports a micromachined silicon uncooled thermal imager intended for applications in automated process control. This paper presents the design, fabrication, and the behavior of cantilever for thermomechanical sensing.