As shown in FIG. 21, the shielding portion 806 is a potting portion provided on the circuit board 8 so as to fill a portion of the circuit board 8 where no electronic component 7 is mounted. The shielding portion 806 seals the upper surface of the circuit board 8 with a resin. The shielding portion 806 covers at least a portion of the graphite sheet 4 on the circuit board side that is not in contact with the heat conductive portion 5. The shielding portion 806 is a potting portion provided to cover the lower surface 40 of the graphite sheet 4 on the circuit board side and to fill/cover/seal the circuit board. The shielding portion 806 protects the upper surface of the circuit board so that a small piece of the graphite sheet 4 peeled off therefrom does not come into contact with the conductive portion of the circuit board. The shielding portion 802 is formed of the same resin material as the shielding portion 706 of the eighth embodiment. Since the potting portion can seal the circuit board 8 from the outside by resin sealing, the shielding portion 806 having high reliability against dropping and/or floating of the small pieces is devisable.
Tenth Embodiment
The tenth embodiment is described with reference to FIG. 22. The tenth embodiment is different from the above-described embodiment in that it includes a coated portion 142 that covers the lower surface of the graphite sheet 4. The configurations, operations, and effects not particularly described in the tenth embodiment are the same as those in the above-described embodiment, and the differences from the above-described embodiment are described below.
