Patent ID: 7913560
Filing Date: 2011-03-29
Classification: G01C

Abstract:
1. An angular rate sensor comprising: a piezoelectric vibration device; and a detection section, wherein the piezoelectric vibration device includes a base substrate, a vibration section having a fixed end affixed to the base substrate and a free end that does not contact the base substrate, and a driving section formed above the vibration section for generating flexural vibration of the vibration section; the vibration section has a first support section, four (first-fourth) cantilever sections supported by the first support section, and a second support section that supports the first support section and equipped with the fixed end; the first support section has a first center line and a second center line that are orthogonal to each other; the first cantilever section and the second cantilever section are symmetrical to each other through a first center line of the first support section in a plan view; the third cantilever section and the fourth cantilever section are symmetrical to each other through the first center line of the first support section in a plan view; the first cantilever section and the fourth cantilever section are symmetrical to each other through the second center line of the first support section in a plan view; the second cantilever section and the third cantilever section are symmetrical to each other through the second center line of the first support section in a plan view; the driving section includes a lower electrode for the driving section, a piezoelectric layer for the driving section formed above the lower electrode for the driving section, and an upper electrode for the driving section formed above the piezoelectric layer for the driving section; the detection section is formed above the vibration section for detecting an angular rate of rotation applied to the vibration section, and has a lower electrode for the detection section, a piezoelectric layer for the detection section formed above the lower electrode for the detection section, and an upper electrode for the detection section formed above the piezoelectric layer for the detection section; during operation of the angular rate sensor, the first and second cantilever sections are flexurally vibrated normal to a plane including the first and second center lines in mutually opposite phases, the second and third cantilever sections are flexurally vibrated normal to the plane including the first and second center lines in mutually opposite phases, and the third and fourth cantilever sections are flexurally vibrated normal to the plane including the first and second center lines in mutually opposite phases; and the first to fourth cantilever sections are flexurally vibrated in a direction of the first center line according to an angular velocity of rotation generated about the second center line.