TY - CHAP AU - Poppe, András AU - Kollár, Ernő AU - Tóth, Zoltán AU - Simonovics, János ED - Németh, Zoltán ED - Nagy, Balázs Vince TI - Foglalatba illeszthető LED modulok hűtő szerelvényeinek termikus vizsgálata T2 - Világítástechnikai Évkönyv 2014-2015 PB - Magyar Elektrotechnikai Egyesület, Világítástechnikai Társaság CY - Budapest PY - 2015 SP - 98 EP - 103 PG - 6 UR - https://m2.mtmt.hu/api/publication/2810732 ID - 2810732 AB - A foglalatba illeszthető LED modulok fejlesztése felkeltette az igényt az ilyen modulok hűtésére szolgáló hűtőszerelvények, hűtőbordák termikus minősítése iránt. E feladat kapcsán a gyártók természetes próbálkozása, az alkatrész szintű LED termikus mérési szabványoknak egy teljes LED modul + hűtőszerelvény rendszerre történő alkalmazása lehet, de ekkor ismerni kell az alkalmazott LED-ek teljes kisugárzott optikai teljesítményét. Annak érdekében, hogy ne kelljen ezt meghatározni, a hűtőszerelvények termikus minősítő mérései során célszerű a LED modulokat termikus viselkedésük szempontjából jól képviselő, termikus helyettesítő modult használni, amelyben LED- ek helyett pl. szilícium diódák vagy tranzisztorok a hőforrások. Jelen írásunkban egy ilyen ún. termikus dummy modult mutatunk be, majd ismertetjük az ezen modul segítségével végzett mérések eredményeit, és azt a módszert, amelynek a segítségével a mérési eredményekből megállapítható a hűtőbordák hőellenállása. LA - Hungarian DB - MTMT ER - TY - THES AU - Kollár, Ernő TI - Termikus kérdések az elektronikában: mérés, modellezés, speciális eszközök PY - 2014 SP - 103 UR - https://m2.mtmt.hu/api/publication/2862742 ID - 2862742 LA - Hungarian DB - MTMT ER - TY - CHAP AU - Poppe, András AU - Kollár, Ernő AU - Toth, Z AU - Simonovics, János ED - Chris, Bailey ED - Kerecsen Istvánné Rencz, Márta ED - Bernhard, Wunderle TI - Characterization of heat-sinks of socketable LED modules using thermal transient testing T2 - 20th International Workshop on THERMal INvestigation of ICs and Systems (THERMINIC'14) PB - Institute of Electrical and Electronics Engineers (IEEE) CY - New York, New York SN - 9781479954155 PY - 2014 PG - 5 DO - 10.1109/THERMINIC.2014.6972497 UR - https://m2.mtmt.hu/api/publication/2699430 ID - 2699430 N1 - Befoglaló mű WoS és MTMT megnevezése nem azonos. Az MTMT-ben 1995 óta standardizált konferenciamegnevezéssel lett a befoglaló mű rögzítve. AB - As socketable LED modules are being developed the need for thermal characterization of heat-sinks aimed at cooling such modules has also arisen. The natural approach from manufacturers is to apply the component level LED thermal testing standards to characterize complete LED module and heat-sink systems. In order to obtain the real thermal resistance of such a complete assembly needs the consideration of the radiant power of the LEDs when calculating the thermal resistance of the complete assembly. Also, the contribution of the LED module, the thermal interface between the module and the heat-sink and the thermal resistance of the heat-sink need to be separated. For the latter problem thermal transient measurements followed by structure function analysis is a solution. To eliminate the need for the measurement of radiant flux of the LED module we suggest building a thermal dummy of the module in question which mechanically is compatible with the module but the heat source is a conventional silicon device instead of LEDs. The paper provides details how such a thermal dummy was created and used in characterizing different heat-sinks aimed at a particular LED module family. LA - English DB - MTMT ER - TY - JOUR AU - Kollár, Ernő AU - Pohl, László AU - Poppe, András AU - Kohári, Zsolt TI - Nonlinear electro-thermal and light output modeling and simulation of OLEDs JF - PERIODICA POLYTECHNICA-ELECTRICAL ENGINEERING AND COMPUTER SCIENCE J2 - PERIOD POLYTECH ELECTR ENG COMP SCI VL - 58 PY - 2014 IS - 2 SP - 43 EP - 53 PG - 11 SN - 2064-5260 DO - 10.3311/PPee.7477 UR - https://m2.mtmt.hu/api/publication/2662740 ID - 2662740 AB - Lighting application of Organic Light Emitting Diodes (OLEDs) has been forecasted and such applications appear already in the high end segment of the market. These devices should provide homogeneous luminance – homogeneity is one of the quality metrics of such devices. Local light generation depends on both the local temperature and the local voltage drop across the light emitting polymer(s) in the device. Due to the large area of these devices the coupled optical, electrical and thermal simulation problem is of distributed nature. Electrical characteristics of organic semiconductor materials used in OLED devices are nonlinear, and their nonlinear temperature-dependence is significant. Measurement and temperature-dependent electrical and optical modeling of OLEDs is presented in this study. The paper addresses the special needs of OLEDs in distributed electro-thermal field simulation. These needs are not handled appropriately yet in the widely used, commercially available simulation tools. However the latest version of our SUNRED field solver algorithm is capable of handling these coupled, non-linear optical-electrical-thermal problems. The new features of the algorithm are demonstrated by modeling some research OLED samples available to us in the Fast2Light project – this way simulation results are compared against measured data. The results suggest that the models and the simulation tool can be used well in OLED design. LA - English DB - MTMT ER - TY - JOUR AU - Kohári, Zsolt AU - Kollár, Ernő AU - Pohl, László AU - Poppe, András TI - Nonlinear electro-thermal modeling and field-simulation of OLEDs for lighting applications II: Luminosity and failure analysis JF - MICROELECTRONICS JOURNAL J2 - MICROELECTRON J VL - 44 PY - 2013 IS - 11 SP - 1011 EP - 1018 PG - 8 SN - 0026-2692 DO - 10.1016/j.mejo.2012.05.015 UR - https://m2.mtmt.hu/api/publication/2683473 ID - 2683473 LA - English DB - MTMT ER - TY - JOUR AU - Pohl, László AU - Kollár, Ernő AU - Poppe, András AU - Kohári, Zsolt TI - Nonlinear electro-thermal modeling and field-simulation of OLEDs for lighting applications I: Algorithmic fundamentals JF - MICROELECTRONICS JOURNAL J2 - MICROELECTRON J VL - 43 PY - 2012 IS - 9 SP - 624 EP - 632 PG - 9 SN - 0026-2692 DO - 10.1016/j.mejo.2011.06.011 UR - https://m2.mtmt.hu/api/publication/2662739 ID - 2662739 N1 - Megjegyzés-24003437 :doi 10.1016/j.mejo.2011.06.011 AB - Large area OLEDs aimed at lighting applications should provide homogeneous luminance—homogeneity is one of the quality metrics of such devices. Local light generation depends on both the local temperature and the local voltage drop across the light emitting polymer(s) in the device. Therefore the thermal and electrical engineering of OLEDs aimed at lighting applications is critical. Due to the large area of these devices the coupled electrical and the thermal simulation problem is of distributed nature. Electrical characteristics of organic semiconductor materials used in OLED devices are highly nonlinear, and their nonlinear temperature-dependence is significant. In our present approach to distributed electro-thermal field simulation we address special needs of OLEDs, which is not yet the case with widely used, commercially available simulation tools. In this paper we present the latest version of our SUNRED electro-thermal field solver algorithm capable of handling coupled, non-linear electro-thermal problems. The new features of the algorithm are demonstrated by modeling some research OLED samples available to us in the Fast2Light project—this way simulation results are compared against measured data. LA - English DB - MTMT ER - TY - CHAP AU - Pohl, László AU - Kollár, Ernő ED - Bernard, Courtois ED - Marta, Rencz TI - Extension of the SUNRED algorithm for electro-thermal simulation and its application in failure analysis of large area (organic) semiconductor devices T2 - Proceedings of the 17th International Workshop on THERMal INvestigation of ICs and Systems (THERMINIC'11) PB - EDA Publishing Association CY - Grenoble SN - 9781457707780 PY - 2011 SP - 195 EP - 200 PG - 6 UR - https://m2.mtmt.hu/api/publication/2668689 ID - 2668689 LA - English DB - MTMT ER - TY - JOUR AU - Maák, Pál AU - Takacs, T AU - Barócsi, Attila AU - Kollár, Ernő AU - Richter, Péter TI - Thermal behavior of acousto-optic devices: effects of ultrasound absorption and transducer losses. JF - ULTRASONICS J2 - ULTRASONICS VL - 51 PY - 2011 IS - 4 SP - 441 EP - 451 PG - 11 SN - 0041-624X DO - 10.1016/j.ultras.2010.11.010 UR - https://m2.mtmt.hu/api/publication/2662802 ID - 2662802 AB - In the present paper we analyze the electric and acoustic losses in acousto-optic devices, especially in their ultrasonic transducers and the related thermal effects. We include electric and acoustic losses into the classical electric equivalent model of the transducer, to explain the characteristics of the measured electric and thermal behavior. Measured temperature distributions on the acousto-optic crystal faces serve visualization of the conversion efficiency of the radio-frequency input to bulk acoustic waves. We show that the pronounced acoustic frequency dependence of the temperature distribution is in correlation with the frequency dependent losses in the transducer and in the bulk. We also demonstrate experimentally the effectiveness of our active and passive heat removing and temperature stabilization methods. LA - English DB - MTMT ER - TY - JOUR AU - Székely, Vladimir AU - Kollár, Ernő AU - Somlay, Gergely László AU - Szabó, Péter Gábor AU - Juhász, László AU - Kerecsen Istvánné Rencz, Márta AU - Vass-Várnai, András TI - Statikus TIM teszter tervezése JF - HIRADÁSTECHNIKA (1962) J2 - HIRADÁSTECHNIKA VL - 66 PY - 2011 IS - 1 SP - 37 EP - 47 PG - 11 SN - 0018-2028 UR - https://m2.mtmt.hu/api/publication/2662204 ID - 2662204 LA - Hungarian DB - MTMT ER - TY - CHAP AU - Pohl, László AU - Kollár, Ernő AU - Poppe, András ED - Bernard, Courtois ED - Kerecsen Istvánné Rencz, Márta TI - Nonlinear electro-thermal OLED model in SUNRED field simulator T2 - Proceedings of the 16th International Workshop on THERMal INvestigation of ICs and Systems (THERMINIC'10) PB - IEEE CY - Barcelona SN - 9782355000126 PY - 2010 SP - 149 EP - 153 PG - 5 UR - https://m2.mtmt.hu/api/publication/2655966 ID - 2655966 AB - Lighting purpose organic light-emitting devices have to be answer to high electrical and thermal requirements. Design of these devices needs special engineering. The electrical current and dissipated power distribution in an OLED needs electro-thermal field simulation. The algorithm in our simulation tool, SUNRED, had to be extended to be able to handle highly nonlinear electrical OLED characteristics, and nonlinear temperature dependence. We have created an electro-thermal model for the OLED samples given by our project partner. The nonlinear semiconductor junction model is applied in SUNRED. This article surveys the new OLED model and presents the application in electro-thermal simulations. Finally we compare the measurement, model and simulation results. LA - English DB - MTMT ER -