| 摘要 |
PURPOSE:To enable response to an extremely trace quantity of adsorptive molecules with high sensitivity and high reproducibility by chemically modifying the surface of a frequency conversion element by a silane coupling agent or titanium coupling agent. CONSTITUTION:A surface acoustic wave element 1 is formed with an input converter 5 and an output converter 6 at a prescribed spacing on a quartz substrate 4. The converters 5, 6 are aluminum electrodes formed by etching and vapor deposition. The input signal is converted to surface acoustic wave by the converter 5 and propagates on the surface of the quartz substrate 4. The wave is returned to the electric signal by the converter 6 parted by a desired delay distance. The phase speed of the surface acoustic wave is delayed by the weight increase of a detecting part 8 and the oscillation frequency of the loop decreases in proportion to the adsorption quantity when a different chemical material is taken as the material to be adsorbed into the detecting part 8. The oscillation frequency restores the original value when the material to be adsorbed is detached. The absorption quantity and absorption/ desorption behavior of the material to be adsorbed to the detecting part 8 are monitorable if the change in the transmission frequency is measured by a frequency counter 3. |
