Flow sensor
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsTomoya Yamakawa, Motohisa Taguchi
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Abstract
To obtain a flow sensor having excellent responsibility, sensitivity and reliability and high flow detection accuracy by suppressing the deformation of a diaphragm, first additional patterns are formed on a side opposite to connection patterns of a heating element so that thin film patterns formed on the diaphragm become almost symmetrical, thereby suppressing the deformation of the diaphragm caused by internal stress between a base film or protective film and a platinum film forming the thin film patterns and the differences of mechanical or thermal properties therebetween.
Claims22
A flow sensor for measuring the flow rate of a fluid flowing over a flow detection element by supplying power to a heating element, the flow detection element comprising:
- a diaphragm formed by removing part of a substrate;
- a heating element made of a heat sensitive resistor film and formed on the diaphragm;
- electrode portions for the heating element formed on the substrate;
- lead patterns extending from the electrode portions to a portion near the diaphragm;
- and
- connection patterns, at least part of which are formed on the diaphragm, for connecting the lead patterns to a patter of the heating element, wherein
- additional patterns are formed on the diaphragm or the diaphragm and a portion therearound so that a tin film pattern including the additional patterns formed on the diaphragm become substantially symmetrical on the diaphragm with respect to a center axis in a longitudinal direction and a transverse direction of the diaphragm.
Dependencies are inferred from the claim text.