Patent ID: 8176772
Filing Date: 2012-05-15
Classification: G01N

Abstract:
1. A piezoelectric sensor electrically connected to a measuring device main body in order to sense a substance to be measured in a sample solution, the piezoelectric sensor comprising: a wiring board which has a connection terminal portion connected to the measuring device main body and on whose one surface an electrode electrically connected to the connection terminal portion and a recessed portion forming an airtight space are provided; a piezoelectric resonator which includes excitation electrodes provided on one surface and on another surface of a plate-shaped piezoelectric piece respectively and electrically connected to the electrode, and which is provided on said wiring board to cover the recessed portion, with the excitation electrode on the other surface facing the recessed portion; a pressing member in which a solution storage space having a bottom surface being the one surface of said piezoelectric resonator is formed, and which is made of an elastic material provided to surround the solution storage space; and a solution injection cover placed opposite said wiring board to cover said pressing member, and having, on a front surface thereof, an injection port which communicates with the solution storage space and through which the sample solution is injected into the solution storage space, wherein said pressing member includes an annular projection which presses a portion, of the one surface of said piezoelectric resonator, outside the recessed portion toward said wiring board to fix a position of said piezoelectric resonator; a tip of the annular projection has an acute angle, with both side surfaces of the annular projection getting smaller in diameter toward a lower side and a distance between the both side surfaces getting smaller toward the lower side; and a natural frequency of said piezoelectric resonator changes when the substance to be measured in the sample solution stored in the solution storage space comes into contact with the one surface of said piezoelectric resonator.