Electronic device having sealed heat-generation element
An electronic device includes: a resin substrate that includes insulation resin on which wiring made of conductive material is provided; a heat-generation element that is a circuit element mounted on a first surface of the resin substrate, and is operated to generate heat; and a sealing resin that is provided on the first surface, and seals the heat-generation element. An opposite surface of the sealing resin opposite to a surface of the sealing resin in contact with the first surface is thermally connected to a heat radiation member and mounted on the heat radiation member. Each of the resin substrate and the sealing resin has a bend shape convex toward the opposite surface when each of surrounding temperatures is a normal temperature and has a linear expansion coefficient for maintaining a bend shape convex toward the opposite surface when each of the surrounding temperatures is a high temperature.
1. An electronic device comprising:
a resin substrate that includes insulation resin on which wiring made of conductive material is provided;
a heat-generation element that is a circuit element mounted on a first surface of the resin substrate, and is operated to generate heat; and
a sealing resin that is provided on the first surface, and seals the heat-generation element, wherein:
an opposite surface of the sealing resin opposite to a surface of the sealing resin in contact with the first surface is thermally connected to a heat radiation member and mounted on the heat radiation member;
each of the resin substrate and the sealing resin has a bend shape convex toward the opposite surface when each of surrounding temperatures of the resin substrate and the sealing resin is a normal temperature and has a linear expansion coefficient for maintaining a bend shape convex toward the opposite surface when each of the surrounding temperatures is a high temperature; and
the normal temperature is a temperature when the driving source of the vehicle is in a non-operation state, and the high temperature is higher than the normal temperature.
2. The electronic device according to claim 1 , wherein the heat-generation element is disposed at a center of a plane orthogonal to a thickness direction of the sealing resin.
3. The electronic device according to claim 1 , wherein a linear expansion coefficient α 1 of the sealing resin and a linear expansion coefficient α 2 of the resin substrate are expressed as |α 1 −α 2 |<5×10 −6 /° C.
4. The electronic device according to claim 3 , wherein the sealing resin has the linear expansion coefficient α 1 in a range of 10×10 −6 /° C.<α 1 .
5. The electronic device according to claim 4 , wherein the sealing resin has the linear expansion coefficient α 1 in a range of 10×10 −6 /° C.<α 1 <17×10 −6 /° C.
6. The electronic device according to claim 1 , wherein the an entire area of the first surface is sealed with the sealing resin.
7. The electronic device according to claim 6 , wherein:
the resin substrate includes substrate through holes provided at four corners of a horizontal plane of the resin substrate in a thickness direction of the resin substrate, and penetrating the resin substrate in the thickness direction of the resin substrate;
the sealing resin includes resin through holes provided at positions facing the substrate through holes, and penetrating the sealing resin in a thickness direction of the sealing resin; and
the resin substrate and the sealing resin are fixed to the heat radiation member via fixing members inserted through the substrate through holes and the resin through holes.
8. The electronic device according to claim 1 , wherein the opposite surface is thermally connected to the heat radiation member via a heat conductive member.