적외선 카메라-레이저 공통광학계의 레이저빔 열 영향성 분석

김성재 한국광학회 2017 한국광학회지 Vol.28 No.4

An infrared camera and laser common-path optical system is applied to DIRCM (directional infrared countermeasures), toincrease boresighting accuracy and decrease weight. Thermal effects of a laser beam in a common-path optical system are analyzedand evaluated, to predict any degradation in image quality. A laser beam with high energy density is absorbed by and heats theoptical components, and then the surface temperature of the optical components increases. The heated optical components of thecommon-path optical system decrease system transmittance, which can degrade image quality. For analysis, the assumed simulationcondition is that the laser is incident for 10 seconds on the mirror (aluminum, silica glass, silicon) and lens (sapphire, zincselenide, silicon, germanium) materials, and the surface temperature distribution of each material is calculated. The wavelengthof the laser beam is 4 μm and its output power is 3 W. According to the results of the calculations, the surface temperatureof silica glass for the mirror material and sapphire for the lens material is higher than for other materials; the main reason forthe temperature increase is the absorption coefficient and thermal conductivity of the material. Consequently, materials for theoptical components with high thermal conductivity and low absorption coefficient can reduce the image-quality degradation dueto laser-beam thermal effects in an infrared camera and laser common-path optical system.

Design and Implementation of Image Processing Algorithms for Focus Alignment of Visible Infrared Laser

Jae-Hwan Jeon,Myoung-Ho Kim,Se-woon Choe,Gwan-Hyung Kim,Am-Suk Oh 한국정보통신학회 2014 2016 INTERNATIONAL CONFERENCE Vol.6 No.1

Context-awareness technology is commonly used in various fields such as detection of objects, persons, and smoke using visible infrared laser. During laser light acquisition process between source and receiver, blockage and attenuation events should be considered. The focus alignment upon receiver plays an important role in the acquisition process. In this paper, focus alignment algorithm of infrared laser in distant (min. 100m) is developed and implemented by visible infrared laser based image processing technique.

Design and Implementation of High-Precision Control System of Focus Alignment of Near-Infrared Laser for Fire Detection

Jae-Hwan Jeon,Myoung-Ho Kim,Se-woon Choe,Gwan-Hyung Kim,Am-Suk Oh 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.11

Recently, context-awareness technology is commonly used in various fields such as detection of objects, persons, and smoke using visible infrared laser. During laser light acquisition process between source and receiver, blockage and attenuation events should be considered. The focus alignment upon receiver plays an important role in the acquisition process so that, In this paper, focus alignment algorithm of infrared laser in distant (min. 100m) is developed and implemented by visible infrared laser based image processing technique and a high-precision control method for auto-focus alignment system using extracted features between transmitters and receiver local oscillators. The present method allows various laser embedded devices using proposed alignment system for deviation in response to the external environment and initial setting for the smoke detection.

Characterization of Laser Welded Joints between Copper Tabs and Multi-layered Foils in Li-Ion Battery

Sung-Kab Kim,Seung-Jun Shin 대한용접·접합학회 2026 대한용접접합학회지 Vol.44 No.2

The rapid expansion of electric vehicles and energy storage systems requires lithium-ion batteries with simultaneously high energy density and reliability. In this regard, the joint between the copper (Cu) current collector and the Cu tab becomes a critical determinant to represent cell performance and safety. However, Cu exhibits low absorptivity under infrared ray lasers and high thermal conductivity. These material characteristics disturb stable keyhole formation and molten pool flow, which result in weld defects. Relevant studies proposed high-power green and blue lasers, beam shaping, and spatial beam oscillation; however, they remain limited to provide the fundamental process knowledge enabling stable and persistent use of infrared ray lasers, which have been widely installed in production lines. This study presents the empirical analysis to characterize laser welded joints between Cu tabs and multi-layered foils in the infrared ray laser. In this study, welding tests are conducted on a joint of a Cu tab and multi-layered foil using a TruDisk 8000 infrared disk laser. Design factors are tab thickness (0.4, 0.5, 0.6 ㎜), foil thickness (5, 6, 8 ㎛), and the number of foil layers (5, 10, 20). Weld performance is evaluated through bead appearance inspections and tensile shear strength (TSS) tests. The maximum TSS for 5 layer stacks is measured, wherein a peak strength of 10.79 ㎏f is achieved with a combination of a 0.5 mm tab and 6 ㎛ foil on a 20-layer stack. The experimental results provide fundamental knowledge to correlate design factors with the joint strength in Cu foil-tab welding assembly.

Near-Infrared Laser-Responsive Photothermal Bubble-Generating PLA Nanoparticles for Controlled Drug Release

이호준,김민아,이창문 한국고분자학회 2021 Macromolecular Research Vol.29 No.3

Stimuli-responsive drug delivery systems can respond to specific external stimuli, resulting in improved treatment outcomes and reduced side effects from their controllable site-specific release ability. The aim of this study was to develop a thermo-responsive bubble-generating drug release platform by near-infrared (NIR) laser irradiation using melanin-perfluorohexane-methotrexate-polylactic acid (Mel @PFH@MTX-PLA) nanoparticles. Mel@PFH@MTX-PLA nanoparticles were successfully prepared without precipitation or aggregation. By adjusting the amount of perfluorohexane (PFH), a size of Mel@PFH@MTX-PLA nanoparticles with optimal conditions was about 52.75 ± 1.41 nm. Due to the photothermal conversion properties of melanin, the temperature of the Mel@PFH@MTX-PLA nanoparticles was increased to about 59.2 oC after 7min of 808 nm NIR laser irradiation at a power density of 1.5 W/cm2. The NIR laser-induced temperature increase triggered additional drug release and caused the phase transition of PFH, resulting in dramatic bubble generation. The resultant Mel@PFH@MTX-PLA nanoparticles can be utilized in biomedical applications as promising carriers for localized and controlled drug delivery.

금과 니켈이 코팅된 베릴륨 구리에 다른 반복율을 적용한 레이저 드릴링 공정의 실험적 연구

손승익(Seungik Son),이동경(Dongkyoung Lee) 대한용접·접합학회 2019 대한용접·접합학회지 Vol.37 No.3

Due to the development of technology and high-tech industrialization, various processing technologies requiring precision are developed and the high degree of precision is further required. Therefore, laser-aided manufacturing has been applied in many engineering fields due to many advantages. However, without understanding fundamental interaction characteristics, its advantages cannot be fully utilized. In this study, the interaction between laser and material is investigated by laser process applied with the different repetition. The wavelength of IR laser used in this experiment is 1064nm. the parameters of IR laser are laser power (20 W), repetition rate (105 kHz, 200 kHz), pulse duration (20 ns) and these parameters are constant during the laser drilling. In addition, the experiment is performed by increasing the laser total energy. For the component analysis of specimen and result of experiment, we use scanning electron microscope (SEM) and energy dispersive X-ray (EDX). And then the result of the Heat affected zone, Material removal zone and Burr is measured. Through this study, it seems that the interaction characteristic is controlled by repetition rate.

쑥뜸과 1064 nm 파장의 근적외선 레이저로 가열된 아가젤 조직 팬텀 심부의 온도분포 가시화

조지용,김중경 한국가시화정보학회 2010 한국가시화정보학회지 Vol.8 No.4

A laser moxibustion therapy device having effect similar to that of traditional moxibustion is being developed using 1064 nm infrared laser. The therapy device allows direct interaction of laser light with the tissue rendering temperature distribution both on the skin surface and deep under the skin. We made a device that could measure temperature of deep under the surface of agar gel tissue phantom using thermocouples. A thermal imaging camera was used to verify results from the temperature measurement device. We compared the characteristics of heat transfer inside the tissue phantom during moxibustion and laser irradiation. The temperature distribution measured by thermocouples was found to be similar to that of distribution given by thermal imaging camera.

Design and Development of a Single-photon Laser and Infrared Common Aperture Optical System

Wu Hongbo,Zhang Xin,Tan Shuanglong,Liu Mingxin,Wang Lingjie,Yan Lei,Liu Yang,Shi Guangwei 한국광학회 2022 Current Optics and Photonics Vol.6 No.2

A single-photon laser and mid-wave infrared (MWIR) common aperture optical system was designed and developed to detect and range a long-distance civil aviation aircraft. The secondary mirror of the Ritchey-Chretien (R-C) optical system was chosen as a dichroic lens to realize the design of a common aperture system for the laser and MWIR. Point spread function (PSF) ellipticity was introduced to evaluate the coupling efficiency of the laser receiving system. A small aperture stop and narrow filter were set in the secondary image plane and an afocal light path of the laser system, respectively, and the stray light suppression ability of the small aperture stop was verified by modeling and simulation. With high-precision manufacturing technology by single point diamond turning (SPDT) and a high-efficiency dichroic coating, the laser/MWIR common aperture optical system with a φ300 mm aluminum alloy mirror obtained images of buildings at a distance of 5 km with great quality. A civil aviation aircraft detection experiment was conducted. The results show that the common aperture system could detect and track long-distance civil aviation aircraft effectively, and the coverage was more than 450 km (signal-tonoise ratio = 6.3). It satisfied the application requirements for earlier warning and ranging of long-range targets in the area of aviation, aerospace and ground detection systems.

Local Temperature Determination of Optically Excited Hollow Gold Nanorods

Joshua Fernandes,Sangmo Kang 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11

This numerical study is to investigate the photothermal response of hollow gold nanorod (HGNR) illuminated by an ultrafast laser pulse. Finite element modelling (FEM) based software COMSOL Multiphysics is used to perform this two-temperature study where the temperature profile inside and around the HGNRs is evaluated. The near-infrared (NIR) light can easily penetrate deep into soft tissues and blood for biomedical applications. Hence the usage of femtosecond laser pulse can provide high peak intensity in a short duration by utilizing low pulse energy, which can easily reduce the laser energy and the time of laser-biological action. For the HGNR, the influence of laser fluence on the maximum temperature reached at the HGNR surface is studied. This study aims at providing some useful insights for the applications of these gold nanorods in drug delivery and photothermal tumor therapy.

Preparation of Melanin-Poly(ethylene glycol) (PEG) Nanoparticles and Their Photothermal Effects by a NIR Laser

김민아,김미리,김동운,윤순도,이창문 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1

In this study, melanin was conjugated with polyethylene glycol (PEG) to increase its availability in biomedical applications. Melanin-PEG conjugate (MPC) was self-assembled in water into spherical nanoparticles. The mean size of the MPC nanoparticles was 237.8 nm. To evaluate the photothermal properties, MPC nanoparticles were exposed to an 808 nm near infrared laser with a power density of 1.5W/㎠. The temperature of MPC nanoparticle solution increased by 86 °C at 5 mg/mL after irradiation for 3 min. To investigate in vivo photothermal effect MPC nanoparticles was injected into the thigh muscle of a mouse and exposed to the same laser condition. The temperature of the site increased significantly by 65.4 °C within 3 min. The MPC nanoparticles can efficiently convert near infrared (NIR) light into heat, which makes it suitable for a photothermal therapeutic agent (PTA). Thus, we believe that MPC nanoparticles have ability as a PTA for NIR laser-induced photothermal cancer therapy.