| 摘要 |
PURPOSE:To make a sensor compact and to detect even the size of three- dimensional accelerations by detecting the change in resistance value of a piezoelectric resistor based on the output of a bridge circuit, and judging the amount of displacement in the specified directions. CONSTITUTION:In a semiconductor acceleration sensor B, the central part of a crystal substrate 11 is etched in a square shape from the lower part. The sensor B comprises a diaphragm part 12 and piezoelectric resistors 14 which are provided on the diaphragm 12. The diaphragm part 12 is an elastic part and surrounds a mass part 13 of a thick part. A plurality of the resistors 14 are arranged in the two different directions to each other in the plane of the substrate 11. The resistors 14 form a bridge circuit. The amount of the displacement of the resistor 14 is judged based on the output of the bridge circuit. At this time, the resistors 14 can judge the respective amounts of displacements in the direction of the short side and the other direction perpendicular to the short-side direction based on the output of the bridge circuit. Thus the magnitude of the acceleration in the specified axial direction can be obtained accurately and highly precisely. The magnitudes of three-dimensional accelerations can be detected with the compact sensor. |
