| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a thermal type flowmeter capable of surely detecting a minute fluid flow while suppressing zero point drifts regardless of variations in ambient temperature. <P>SOLUTION: In the thermal type flowmeter, a sensor chip which is equipped with a thin diaphragm and a substrate section for supporting the thin diaphragm in the air, is insulated thermally and supported so as to be positioned at a flow channel of an ambient gas. The substrate section has a first heater, and the thin diaphragm section has a second heater. The first heater is driven so as to generate heat at a first constant temperature higher than that of the ambient gas, and the second heater is driven so as to generate heat at a second constant temperature higher than the heated temperature of the first heater, and at this time, at least one of drive electric signals e.g., drive power, voltage and current applied to the second heater, is obtained as a flow signal of the ambient gas. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
