| 摘要 |
PROBLEM TO BE SOLVED: To depress the transmissibility of a high frequency electromagnetic wave by an skin effect, and to reduce a high frequency noise to prevent a malfunction of a flow measurement device, by making a couter-bore to at least one point of one side or both sides of an electronic substrate such as ceramic before a plate substrate firing, and then firing the electronic substrate. SOLUTION: In an air flow measurement device disposed in a sub-passage formed in a main passage functioning as an air passage of an inner combustion engine, an electronic circuit substrate driving the air flow measurement device is provided in a module. The electronic circuit substrate passes a current through a voltage supply source terminal 14, and an earth ground terminal 16. An electric signal corresponding to the flow amount of air is put out from a metallic conductor 10 and a thick-film resistor 11 fired on one side of the substrate and a heatingresistor terminal 17 and a temperature sensitive resistor terminal 18 connected to an electronic element 12. The electronic circuit substrate is mainly made of ceramic, and makes a couter-bore shape at a prescribed point on one side thereof and then is subjected to firing. Therefore, the transmissibility of a high frequency electromagnetic wave is depressed.
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