| 摘要 |
<p>PURPOSE:To enable highly-sensitive detection of a flow rate and also to improve detection sensitivity in a low flow rate area by separating a heater from a temperature measuring resistor by a prescribed distance and by providing a planar area part. CONSTITUTION:A thin-film diaphragm 3a insulated thermally from a semiconductor substrate 1 with an air gap 2 interposed is formed in the central part of the surface of this substrate 1, a heater element 4 is formed in the central part of this diaphragm 3a and, moreover, temperature measuring resistance elements 5 and 6 being independent of each other are formed on the opposite sides of the element 4. The element 5 on the upstream side is formed and disposed on the windward side, while the element 6 on the downstream side is formed and disposed down on the leeward side, and thus relatively wide rectangular planar areas 12 are formed on the opposite sides of the element 4. By providing the areas 12 between the element 4 and the elements 5 and 6, excessive conduction of a heat of the element 4 to the elements 5 and 6 is prevented, and therefore detection sensitivity in a low flow rate area, in particular, can be greatly improved.</p> |
