Integrated microsensor for precise, real-time measurement of junction temperature of surface-mounted light-emitting diode

Choi, Hyunjin,Choi, Woohyuk,Lim, Jiseok,Choi, Jungwook Elsevier 2019 Sensors and actuators. A Physical Vol.298 No.-

<P><B>Abstract</B></P> <P>Light-emitting diodes (LEDs) are widely used in many industrial applications owing to their high performance and efficiency compared with conventional lighting systems. However, a considerable amount of input power is inevitably dissipated into heat at the LED junction, which can degrade the performance and reliability of the LED; thus, it is important to monitor the change in the junction temperature of the LED. In this study, we present a micro-temperature sensor-integrated surface-mounted device (SMD) for accurate and real-time measurement of the junction temperature of an LED. The LED is mounted on a microfabricated Pt sensor in a similar way to the typical SMD assembly. The heat generated at the LED junction is conductively transferred to the microsensor, increasing the temperature and changing its electrical resistance. In contrast to the conventional techniques for thermal characterization of LEDs, the integrated microsensor provides real-time information on the junction temperature with high precision, reproducibility, and simplicity. Additionally, the temperature of the solder, which is not easily accessible but is closely related to the reliability of the LED, can be estimated by analyzing the thermal resistance of the LED package. Experimental and numerical results indicate a linear correlation (R<SUP>2</SUP> = 0.988) between the junction and sensor temperatures, which is practically useful for the thermal management of the miniaturized SMD-LED.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Methodology for measuring LED junction temperature is proposed. </LI> <LI> Pt micro-temperature sensor-integrated SMD-LED is designed and fabricated for real-time measurement of junction temperature. </LI> <LI> Highly linear correlation of the temperature between the microsensor and the junction is experimentally found. </LI> <LI> Analysis of structure function, thermal resistance, and numerical calculation of SMD-LED validates measurement accuracy of Pt microsensor. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Minimum Time Algorithm for Gantry Travel

Soon-Ho Kim,Chi-Su Kim 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.8

Surface mount technology is a method of applying lead solder to PCB pads to fix Surface Mount Device (SMD) components on PCBs. SMT facilitates the pickup of the electronic component and accurate placement on PCBs. Heads and nozzles for each axis use suction cups to pick up electronic components from tape feeders. The components are inspected before a vision camera to check pickup location and alignment, and then are moved to PCBs waiting on the conveyer for placement. This paper presents an algorithm that identifies the shortest path from sLa to pLb without stopping before the camera for visual inspection. The simulations verified that the fly motion method reduced the time involved by 16% compared to the stop motion method.

이형 부품 표면실장기에 대한 겐트리 경로 문제의 최적 알고리즘

정재욱(Jaewook Jeong),태현철(Hyunchul Tae) 한국산업경영시스템학회 2020 한국산업경영시스템학회지 Vol.43 No.4

This paper proposes a methodology for gantry route optimization in order to maximize the productivity of a odd-type surface mount device (SMD). A odd-type SMD is a machine that uses a gantry to mount electronic components on the placement point of a printed circuit board (PCB). The gantry needs a nozzle to move its electronic components. There is a suitability between the nozzle and the electronic component, and the mounting speed varies depending on the suitability. When it is difficult for the nozzle to adsorb electronic components, nozzle exchange is performed, and nozzle exchange takes a certain amount of time. The gantry route optimization problem is divided into the mounting order on PCB and the allocation of nozzles and electronic components to the gantry. Nozzle and electronic component allocation minimized the time incurred by nozzle exchange and nozzle-to-electronic component compatibility by using an mixed integer programming method. Sequence of mounting points on PCB minimizes travel time by using the branch-and-price method. Experimental data was made by randomly picking the location of the mounting point on a PCB of 800mm in width and 800mm in length. The number of mounting points is divided into 25, 50, 75, and 100, and experiments are conducted according to the number of types of electronic components, number of nozzle types, and suitability between nozzles and electronic components, respectively. Because the experimental data are random, the calculation time is not constant, but it is confirmed that the gantry route is found within a reasonable time.

Feeder Re-assign Problem in a Surface Mount Device with a Piano-Type Multi-Headed Gantry

Hyunchul Tae,Byung-In Kim 대한산업공학회 2013 Industrial Engineeering & Management Systems Vol.12 No.4

A surface mount device (SMD) assembles electronic components on printed circuit boards (PCB). Since a component assembly process is a bottleneck process in a PCB assembly line, making an efficient SMD plan is critical in increasing the PCB assembly line productivity. Feeder assignment is an important part of the SMD plan optimization. In this paper, we propose a feeder re-assign improvement algorithm for a specific type of SMD machine with a piano type multi-head gantry. Computational results on some real-world benchmark data sets show the effectiveness of our proposed algorithm.

직렬형 컨볼루션 신경망에 의한 SMD 부품의 조립 불량 분류 방법

류종현(Jong-Hyun Ryu),김영규(Young-Gyu Kim),박태형(Tae-Hyoung Park) 대한전기학회 2019 전기학회논문지 Vol.68 No.10

In this paper, we propose the classification method of assembly defects in the surface mount technology process. We used a cascade convolution neural network which two convolutional neural networks were merged into one network, for assembly defect classification. The first network classifies whether the surface mount device (SMD) is defect or not. The second network classify the result of the first network more detail. We classified the SMD defects as six types using a cascade convolution neural network. Experiment result shows that the proposed method can optimize memory usage and improve classification accuracy compared to previous methods.

A Machine Vision System for Inspecting Tape-Feeder Operation

Cho Tai-Hoon Korean Institute of Intelligent Systems 2006 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.6 No.2

A tape feeder of a SMD(Surface Mount Device) mounter is a device that sequentially feeds electronic components on a tape reel to the pick-up system of the mounter. As components are getting much smaller, feeding accuracy of a feeder becomes one of the most important factors for successful component pick-up. Therefore, it is critical to keep the feeding accuracy to a specified level in the assembly and production of tape feeders. This paper describes a tape feeder inspection system that was developed to automatically measure and to inspect feeding accuracy using machine vision. It consists of a feeder base, an image acquisition system, and a personal computer. The image acquisition system is composed of CCD cameras with lens, LED illumination systems, and a frame grabber inside the PC. This system loads up to six feeders at a time and inspects them automatically and sequentially. The inspection software was implemented using Visual C++ on Windows with easily usable GUI. Using this system, we can automatically measure and inspect the quality of ail feeders in production process by analyzing the measurement results statistically.

세라믹 패키지를 이용한 표면실장형 다이오드의 제작과 특성평가

전명표,조상혁,한익현,조정호,김병익,유인기,Chun, Myoung-Pyo,Cho, Sang-Hyeok,Han, Ik-Hyun,Cho, Jeong-Ho,Kim, Byung-Ik,Yu, In-Ki 한국전기전자재료학회 2007 전기전자재료학회논문지 Vol.20 No.5

Generally, a diode package consists of the synthetic resin that has good durability but low thermal conductivity. The surface mounted type fast recovery diode was fabricated by using ceramic package. Its main manufacture processes are composed of soldering, sillicon coating and side termination. And it has various advantages that diode is small, easy manufacture and fast cooling. The electric characteristics of the diode such as reverse recovery time, breakdown voltage, forward voltage, and leakage current were 5.28 ns, 1322 V, 1.08 V, $0.45\;{\mu}A$, respectively.

A Machine Vision System for Inspecting Tape-Feeder Operation

Tai-Hoon Cho 한국지능시스템학회 2006 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.6 No.2

A tape feeder of a SMD(Surface Mount Device) mounter is a device that sequentially feeds electronic components on a tape reel to the pick-up system of the mounter. As components are getting much smaller, feeding accuracy of a feeder becomes one of the most important factors for successful component pick-up. Therefore, it is critical to keep the feeding accuracy to a specified level in the assembly and production of tape feeders. This paper describes a tape feeder inspection system that was developed to automatically measure and to inspect feeding accuracy using machine vision. It consists of a feeder base, an image acquisition system, and a personal computer. The image acquisition system is composed of CCD cameras with lens, LED illumination systems, and a frame grabber inside the PC. This system loads up to six feeders at a time and inspects them automatically and sequentially. The inspection software was implemented using Visual C++ on Windows with easily usable GUI. Using this system, we can automatically measure and inspect the quality of all feeders in production process by analyzing the measurement results statistically.

SMD의 패드 정렬이 PCB 전송 특성에 미치는 영향

김창균,이성수,Kim, Chang-Gyun,Lee, Seongsoo 한국전기전자학회 2018 전기전자학회논문지 Vol.22 No.3

인쇄 회로 기판(PCB: printed circuit board)에는 다수의 표면 실장 부품(SMD: surface mount device)이 장착되어 상호 연결되며, 이들을 연결하는 배선의 전송 특성이 나빠지면 시스템의 성능이 감소하게 된다. PCB와 SMD를 연결하는 패드는 PCB 전송 특성에 큰 영향을 미치기 때문에 패드의 위치도 최적화되어야 한다. 본 논문에서는 패드 정렬이 PCB 전송 특성에 미치는 영향을 시뮬레이션 하였다. 주파수가 비교적 낮은 경우에는 패드 정렬이 PCB 전송 특성에 큰 영향을 미치지 않지만 주파수가 높아지거나 패드 크기가 커질수록 패드 정렬에 따른 영향이 커진다. 따라서 목표 주파수와 패드 크기에 따라 세심하게 패드 정렬을 선택할 필요가 있다. 특히 12~18 GHz의 Ku-밴드 주파수 대역에서는 기존의 중앙 정렬 패드보다 제안하는 측면 정렬 패드가 전체적으로 유리하다. Many SMDs (surface mount device) are mounted and mutually connected on a PCB (printed circuit board). System performance degrades when their transmission characteristics are bad. Pads connecting a PCB and SMDs affects PCB transmission characteristics significantly, so pad should be properly aligned to optimize impedance matching. In this paper, effects on PCB transmission characteristics are simulated by pad alignment. When frequency is relatively low, pad alignment seldom affect PCB transmission characteristics, but it affects more and more when frequency or pad size becomes larger. Therefore, pad alignment should be carefully chosen based on target frequency and pad size. Especially, the proposed edge-aligned pad is generally more advantageous over the conventional centered-aligned pad in 12~16 GHz Ku-band frequency.

유연생산 표면실장기에 대한 알고리즘

태현철(H. C. Tae),김철(C. Kim),조용주(Y. J. Cho) 한국정밀공학회 2015 한국정밀공학회 학술발표대회 논문집 Vol.2015 No.12월