| 摘要 |
PROBLEM TO BE SOLVED: To prevent cracks in an insulating board, disconnection of an electrode ad solder peeling by performing the thermal expansion coefficient of the insulating board of a magnetic sensor to be almost equal to the thermal expansion coefficient of a circuit board. SOLUTION: A metal board which contains iron as the major component is used as a circuit board 1, and crystallized glass is used as an insulating board 5. When a lithium silicate glass is used, its thermal expansion coefficient is almost as follows;α1=90-130×10<-7> / deg.C. On the other hand, the circuit board 1 is a metal board containing iron as the major component, and the thermal expansion coefficient of the circuit board 1 is almost as follows;α2=115×10<-7> / deg.C. Since both thermal expansion coefficients are almost equal, cracks on the insulating board 1 of a magnetic sensor 9 by the thermal stress caused by cooling at the time of soldering the electrode 7 of the magnetic sensor 9 to the land 2 of the circuit board 1 and the thermal stress caused by rapid temperature change in the using environment, disconnection of the electrode 7 caused by cracks and peeling of solder 8 are prevented.
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