Angular velocity sensor
An angular velocity sensor includes: a frame including a pair of first beams extending in a first direction and opposed to each other in a second direction orthogonal to the first direction, a pair of second beams extending in the second direction and opposed to each other in the first direction, and connections between those pairs; a drive unit that vibrates the frame in a first plane, to which the first and second directions belong, in a vibration mode in which when one pair of those pairs move closer to each other, the other move away from each other, and vice versa; a first detector that detects, based on the amount of deformation of the frame in the first plane, an angular velocity around an axis of a third direction orthogonal to the first plane; and a support mechanism including a base portion and joint portions.
1. An angular velocity sensor, comprising:
a frame including
a pair of first beams that extend in a first direction and are opposed to each other in a second direction orthogonal to the first direction,
a pair of second beams that extend in the second direction and are opposed to each other in the first direction, and
a plurality of connections configured to connect between the pair of first beams and the pair of second beams;
a drive unit configured to vibrate the frame in a first plane, to which the first direction and the second direction belong, in a vibration mode in which when one pair of the pair of first beams and the pair of second beams move closer to each other, the other pair move away from each other, and when the one pair move away from each other, the other pair move closer to each other;
a first detector configured to detect an angular velocity around an axis of a third direction orthogonal to the first plane when the frame vibrates in the vibration mode.
2. The angular velocity sensor according to claim 1 , wherein
the pair of first beams includes a pair of first beam portions including first curved portions that form first recesses by projecting to a direction in which the first curved portions are opposed to each other, and
the pair of second beams includes a pair of second beam portions including second curved portions that form second recesses by projecting to a direction in which the second curved portions are opposed to each other.
3. The angular velocity sensor according to claim 2 , wherein
at least a part of the plurality of joint portions is positioned in one of the first recess and the second recess.
4. The angular velocity sensor according to claim 1 , further comprising:
first pendulums that are provided in a pair of first connections in a diagonal relationship out of the plurality of connections and vibrate in synchronism with vibration of the frame in the first plane;
second pendulums that are provided in a pair of second connections in a diagonal relationship out of the plurality of connections and vibrate in synchronism with vibration of the frame in the first plane; and
a second detector configured to detect angular velocities around axes of two predetermined directions in the first plane, based on the amounts of deformation of the first pendulums and the second pendulums in a direction orthogonal to the first plane.
5. The angular velocity sensor according to claim 1 , further comprising a base portion and a plurality of joint portions.
6. The angular velocity sensor according to claim 5 , wherein the base portion includes an inner peripheral portion surrounding the frame.
7. The angular velocity sensor according to claim 6 , wherein the plurality of joint portions are configured to join between the inner peripheral portion and the plurality of connections.
8. The angular velocity sensor according to claim 5 , wherein each of the plurality of joint portions includes
a first end portion that is connected to one of the connections,
a second end portion that is connected to the inner peripheral portion, and
a structural portion that is provided between a first end portion and a second end portion of the joint portions.
9. The angular velocity sensor according to claim 5 , wherein the base portion includes
a terminal array including a plurality of terminal portions that are arranged along one of the first direction and the second direction, and
a groove provided along the terminal array between the terminal array and the inner peripheral portion.
10. The angular velocity sensor according to claim 9 , wherein
the base portion is a square frame body including two sides opposed to each other in the first direction and two sides opposed to each other in the second direction, and
the groove includes
first groove portions that are provided in the two sides opposed to each other in the first direction, and
second groove portions that are provided in the two sides opposed to each other in the second direction and communicate with the first groove portions.
11. The angular velocity sensor according to claim 1 , wherein the frame is an annular frame.
12. The angular velocity sensor according to claim 1 , wherein the first detector is configured to detect the angular velocity based on an amount of deformation of the frame.