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December 2015 • The PCB Magazine 111 tronics industry, the need for such technology is on the rise. A 2013 report from BPA Consult- ing Ltd. [1] ,offered up a comprehensive review of opportunities for PCBs, which serve thermal management and/or power management needs in high power applications. It additionally pro- vides an analysis of the different types of MIB structures identified relative to market oppor- tunities for both board fabricators and material suppliers. In the report the authors identify a number of different markets where metal base substrates are likely to see expanded use. Those markets include: automotive subsystems, sol- id-state lighting, digital control of electrical power, distributed energy harvesting, TV and display backlighting, domestic appliances and RF power. In summary, the employment of metal sheet in the manufacture of printed circuits has a long history and the technology is faithfully served a number of applications over the last few decades and there is every reason to believe that the basic concept will see growth in the future. One scenario which should eventually prove compelling is one where metal actually becomes the board rather than just part of it es- pecially when the Occam process and/or SAFE (solderless assembly for electronics) methods are employed. For such structures the metal of highest interest is aluminum which is the third most abundant element on the planet and com- prises 8.3% of the earth's crust. Aluminum as many attractive properties including: lightness, low-cost ($0.72 per pound), close match in CTE to copper (22 versus 18 ppm per degree C), easy conversion of its surfaces to alumina by anodiz- ing, environmental friendliness/sustainability, and of course, thermal conductivity. A future article will examine this subject matter in more detail. PCB References 1. BPA Consulting, Metal in the Board. Verdant electronics Founder and president Joseph (Joe) Fjelstad is a four-decade veteran of the electronics industry and an international authority and innovator in the field of electronic interconnection and packaging technologies. Fjelstad has more than 250 u.S. and interna- tional patents issued or pending and is the author of Flexible Circuit Technology. hybrid optoelectronic devices based on blends of hard and soft semiconductors combine the properties of the two material types, opening the possibility for devices with novel functionality and properties, such as cheap and scalable solution- based processing methods. however, the efficien- cy of such devices is limited by the relatively slow electronic communication between the material components that relies on charge transfer. a phenomenon called Förster resonant energy transfer (Fret) was recently predicted and experi- mentally observed in hybrid structures combin- ing an inorganic quantum well with soft semicon- ductor film. Fret is a radiationless transmission of energy occurring on the nanometer scale from a donor to an acceptor molecule,which promotes energy rather than charge transfer. researchers from the university of cyprus and cyprus university of technology, along with col- leagues from the university of crete, Greece, have conducted a comprehensive investigation on how various structural and electronic param- eters affect Fret in structures of nitride quantum wells with light-emitting polymers. Based on their studies, the researchers discuss the process to optimize the energy transfer process and iden- tify the limitations and implications of the Förster mechanism in practical devices. the work dem- onstrates the importance of understanding Fret in hybrid structures that could pave the way for developing novel devices such as high-efficiency leds and solar cells. High-performance LEDs and Solar Cells See New Limits e.i. Files INSULATED METAL BASE CIRCUITS—AN ENABLING TECHNOLOGY FOR POWER ELECTRONICS

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