Patent ID: 9219169
Filing Date: 2015-12-22
Classification: G01C,H01L

Abstract:
1. An angular velocity sensor for detecting an angular velocity, comprising: a substrate having a stationary portion, wherein one direction on a plane surface of the substrate is defined as an x-axis direction, another direction on the plane surface of the substrate perpendicular to the x-axis direction is defined as a y-axis direction, and another direction perpendicular to the x-axis direction and the y-axis direction is defined as a z-axis direction; two pair of driver weights including two detector weights including: a first detector electrode arranged at a first distance from the first detector weight; and a second detector electrode arranged at a second distance from the second detector weight, wherein: a first capacitance is formed between the first detector weight and the first detector electrode and a second capacitance is formed between the second detector weight and the second detector electrode; the annular velocity, application of which oscillates the first detector weight and the second detector weight in opposite directions along the z-axis direction and makes a first change in the first distance and a second change in the second distance, is detected by using a differential signal output indicating (i) a variation in the first capacitance caused by the first change in the first distance and (ii) a variation in the second capacitance caused by the second change in the second distance; and the first and second supporting beams and the first and second detector beams are arranged so that an absolute value of a de-coupling ratio D.R. is greater than or equal to 0.07, where fin is a resonance frequency of the first detector weight and the second detector weight in an in-phase mode in which the first detector weight and the second detector weight oscillate in a same direction along the z-axis direction when an impact in the z-axis direction is applied, fanti is a resonance frequency of the first detector weight and the second detector weight in an anti-phase mode in which the first detector weight and the second detector weight oscillate in the opposite directions along the z-axis direction when the impact in the z-axis direction is applied, the substrate includes a joining beam; the first pair of driver weights includes a first outer driver weight connecting with the first inner driver weight through the joining beam; the second pair of driver weights includes a second inner driver weight surrounding the second detector weight and connecting with the second detector weight through the second detector beam, and a second outer driver weight connecting with the second inner driver weight through the joining beam; each of the first inner driver weight and the second inner driver weight is arranged between the first outer driver weight and the second outer driver weight; and when the angular velocity sensor detects the angular velocity, the first inner driver weight and the first outer driver weight of the first pair of driver weights oscillate in the opposite directions along the y direction and the second inner driver weight and the second outer driver weights the second pair of driver weights oscillate in the opposite directions along the y direction.