Patent ID: 8997570
Filing Date: 2015-04-07
Classification: B81B,G01P

Abstract:
1. An acceleration sensor formed of an SOI substrate of a three-layered structure including an active silicon layer, a silicon oxide layer, and a silicon substrate, the acceleration sensor comprising: a frame part; a plurality of beam parts, the beam parts projecting inward from the frame part; and a weight part supported by the beam parts; wherein: each of the beam parts is provided with a strain sensing part; and a width W of each of the beam parts, a length I of each of the beam parts, and an inner frame length L of the frame part satisfy the following relationships of Expressions (1) and (2), wherein the weight part is completely exposed outside on a side of the beam parts so that even when an excessive acceleration up to 10,000 G is applied to the acceleration sensor, the weight part can move without contacting the acceleration sensor, wherein the strain sensing part includes piezoresistors, each having a longitudinal direction substantially parallel to the corresponding beam part, wherein windows are defined by the frame part and the beam parts, each of the windows being provided with a corner portion farthest away from the center of the acceleration sensor defined by sides arranged perpendicular to one another, and wherein the acceleration sensor is a multi-axis sensor capable of sensing strain in an x-axis direction, a y-axis direction and a z-axis direction.