Önder Sünetci, Arcelik
Chip LEDs are being widely used in appliance products for signaling, displaying and also lightening purposes. As these purposes require various LED driving topologies and as these products require harsh operating environmental conditions, LEDs face several types of stresses on appliances. These stresses may be classified as electrical and environmental, while electrical means current, voltage and reverse voltage and environmental means temperature, humidity and vibrations. In a washing machine signaling LED, all these stresses may be combined and applied together (both under transportation and operating phases) while for a refrigerator, vibration, humidity and high temperature may be of less concern. Especially with the matrix driving topology of displays which use LEDs for the segments and icons, LEDs may be exposed to reverse voltage (while in off mode) and humidity together. This case may create pad-peeling failure mechanism for the LEDs and those segments or icons of the displays may become permanently off with being open circuit. The reverse voltage value, specified in LED datasheets is generally specified as having a maximum absolute rating of 5V at 25?C ambient in general. Also reverse voltage reliability test seems generally missing in LED manufacturer technical datasheets. With this study, we simulated pad peeling failure mechanism by applying combined stress of humidity and reverse voltage. Applied test conditions do not instantly create the failure, but there requires some duration for the failure to occur. The failure does not occur under just humidity or under just reverse voltage, combined effect is found to be mandatory.
Önder Sünetci , MS-EEE, is an R&D Senior Specialist at Arcelik Central R&D where he has been working since 2006. He graduated from Istanbul University, Electronics Engineering Department (B.S.) on 2002 and Boshphorus University, Electrical & Electronics Engineering Department (M.S.) on 2010. He worked as an R&D Engineer for the Inform (Legrand) UPS company for the CAD design of PCBs and component approvals between 2002-2005. He then started working for Arcelik, one of the biggest appliance companies in the world, with the responsibilities of electronic component approvals (including LEDs and displays). There, he had various laboratory responsibilities (including Component Approval Lab, Optical Test Lab, Voltage Test Lab, Reliability Lab, Vibration and Thermal Test Lab, Derating Test Lab, Flammability Lab etc.). He was Project Leader for multiple projects, including being Project Coordinator of the international BONACO project (nanocoating development for electronics protection). He visited many electronic component manufacturers (including LEDs) for audit & technical issues. He has 9 patents listed in espacenet.com. He has several papers, including those presented and published in RAMS 2014 & IEEE. He also has Six Sigma Black Belt and working as a Six Sigma Leader in the Electronics Test & Approval Group in Arcelik. He is married having a son and a daughter.