| 摘要 |
<p>Obtained is a sensor for detecting a substance in liquid, the sensor being capable of measuring a substance to be detected in liquid with higher sensitivity and reliability. A sensor 1 for detecting a substance in liquid includes a sensing circuit 2 including a sensing surface-acoustic-wave (SAW) element 4 in which a reaction film to react with a substance in liquid is disposed, a reference circuit 3 including a reference SAW element 6 including an IDT and having no reaction film, a first signal source 8 driving the sensing circuit 2, a second signal source 9 driving the reference circuit 3 and being disposed independently of the first signal source, and a differential circuit 10 outputting a differential output between an output of the sensing circuit 2 and an output of the reference circuit 3. The frequency of a first frequency signal output from the first signal source 8 is different from the frequency of a second frequency signal output from the second signal source 9, thereby making a driving frequency for the sensing SAW element 4 and a driving frequency for the reference SAW element 6 the same or different.</p> |
