Patent ID: 8737075

Claim:
An electronic component unit, comprising: a circuit board on which electronic components are mounted, the electronic components including a heat generating element that generates a heat; a bonding metal foil layer formed on a face of the circuit board; a heat transfer board arranged so that the bonding metal foil layer is interposed between the heat transfer board and the circuit board, the heat transfer board including: a board body having a thermal conductivity higher than that of the circuit board, the board body having a first face and a second face opposite to the first face; an insulative layer, having a thin film shape, formed on the first face; and a heat transfer metal foil layer formed to cover the insulative layer on the first face, the insulative layer being interposed between the board body and the heat transfer metal foil layer; a solder layer between the heat transfer metal foil layer and the bonding metal foil layer; and a heat sink configured to externally dissipate the heat generated in the heat generating element, wherein the circuit board is assembled with the heat sink via the heat transfer board such that (1) the heat transfer metal foil layer on the first face of the board body is soldered to the bonding metal foil layer on the circuit board by the solder layer, and (2) the second face of the board body is superimposed on the heat sink.