Combined heat conductive boards with polyimide dielectrics

Heat-conductive properties of thin heat-conductive polyimide dielectrics have been studied and their thermal resistances have been calculated. Possibility of creating combined printed circuit boards on heat-conductive bases with reduced thermal resistances of polyimide dielectrics from ~ 0.2 to ~ 0.04 °С /W is confirmed. Design parameters and thermal properties of the combined boards with thin polyimide (PI) dielectrics for receivers of concentrated solar radiation are studied. Possibility of providing thermal resistances of PI dielectrics not exceeding 0.43 °С/W has been confirmed. Technical solutions of volumetric light-emitting diode (LED) modules on combined heat-conductive boards, which are 3D-holders-heat sinks, made in the form of single heat-conductive light-reflecting mirrored element, are studied. High thermal characteristics of the modules were achieved due to increase in the area of heat sink holders by more than 2.5 – 3 times compared to flat-type LED modules. Scientific and technical sources were analyzed for selection of modern polyimide materials intended for development and manufacture of combined boards on heat-conductive bases with dielectrics made of polyimide films with increased thermal conductivity up to 0.36 – 0.75 W/(m•K). Potential possibility of creating effective combined printed circuit boards on heat-conductive basis, including those that can be bent, is confirmed using modern industrially manufactured thin heat-conductive PI films with heat-sealable thermoplastic coatings that provide the value of total thermal resistance of boards from 1.5 up to 2.8 °C•cm2/W.