Patent ID: 7299815

Claim:
A micropump check valve device provided in a flow path through which a fluid is passed from an upstream side to a downstream side through pressure change in a micropump, the micropump check valve device comprising: an upstream side member having formed therein a small-bore hole through which the fluid is passed; a downstream side member having formed therein a large-bore hole through which the fluid is passed; and a valve member having a valve mechanism formed therein and sandwiched between the upstream side member and the downstream side member, wherein the valve mechanism of the valve member is composed of a passing hole formed in correspondence to a position and a size of the large-bore hole in the downstream side member, a contacting part for closing the small-bore hole in the upstream side member, the contacting part being formed inside the passing hole in such a manner as to correspond to the position and size of the small-bore hole in the upstream side member, and supporting parts for supporting the contacting part, the supporting parts being formed in such a manner as to bridge across the passing hole, and wherein the valve member has a greater linear expansion coefficient than the upstream side member and the downstream side member.