| 摘要 |
PURPOSE:To obtain stable operation even at high temp., by forming a substrate by utilizing material quality capable of being thermally insulated having heat conductivity of 2w/mk or less. CONSTITUTION:In a flow sensor wherein a heat generating resistor 3a is a provided to the center of a heat insulating substrate, for example, a glass substrate and temp. measuring resistors 4a, 4b are arranged at symmetric positions on both sides of said heat generating resistor 3a so as to hold the resistor 3a therebetween, the temp. of the heat generating resistor 3a is controlled so as to be kept higher by definite temp. than the temp. of a fluid. The flow speed of the fluid is detected on the basis of the current flowing to the heat generating resistor 3a changing corresponding to the flow velocity of the fluid and, at the same time, the temp. difference generated between two temp. measuring resistors 4a, 4b is detected as current difference to detect a flow direction. In this case, by utilizing the glass substrate 1 having heat conductivity of 2w/mk or less, the temp. difference in a chip can be made large and stable operation is obtained. |
