CRYSTAL RESONATOR BIOSENSOR

PURPOSE:To produce the crystal resonator biosensor having unified quality by forming a crystal resonator to a shape which is thin in the central part and thick in the outer peripheral part. CONSTITUTION:The AT cut crystal resonator 1 having electrodes 3, 3 on both surfaces has the circular or rectangular shape which is sectionally thin in the central part and thick in the outer peripheral part. The resonance frequency of the resonator 1 is changed by its mass effect and viscous effect when a liquid sample is injected into a sample cell 2. This frequency settles to a specified frequency unless there is no chemical and physical change in the sample. The resonance frequency of the resonator 1 changes with time if there is adsorption, settlement, viscosity change or the like on the surface of the resonator. The measurement of the deposition of the material by the adsorption and settlement of the material of the sample liquid and the measurement of the viscosity change arising from a gelatinization reaction are executed in this way. The resonator 1 is substantially prevented from being influenced by joining or fixing and supporting of the outer peripheral part to the cell 2 by adhesion, etc., if the section of the resonator is formed to a recessed shape. The change in its electrical performance is thus obviated.