INERTIAL SENSOR

• US 20070131030A1
• Filed: 12/04/2006
• Published: 06/14/2007
• Est. Priority Date: 12/05/2005
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: JEONG, Heewon, FUKUDA, Hiroshi
• Granted Patent: US 7,513,155 B2
• Time in Patent Office: Days
• US Class Current: 73/504.120
• CPC Class Codes: G01C 19/5747 each sensing mass being connected to a driving mass, e.g. driving frames

Abstract

Four sensor units (SUA1 to SUA4) are disposed symmetrically about a point, on both top and bottom and left and right centering around one point of a support (15e). Furthermore, four sensor units (SUA1 to SUA4) are designed so that all the components are fully in tuning-fork structure. Drive frames (5, 5) of the sensor units (SUA1, SUA2) disposed adjacent to each other in a first direction (Y) are vibrated in mutually inverted phases, and drive frames of the other sensor units (SUA3, SUA4) disposed adjacent to each other in a second direction (X) are vibrated in mutually inverted phases as well. Moreover, the drive frames of the sensor units (SUA1, SUA2) and the drive frames of the other sensor units (SUA3, SUA4) are operated in synchronization in the state in which phases are shifted by 90 degrees. Whereby, it is possible to reduce or prevent vibration coupling in the driving direction and in the detection direction, and the leakage (loss) of excitation energy and Coriolis force. Thereby, performance of an inertial sensor is improved.

Claims

1. An inertial sensor comprising:

a basement layer including a first principal plane and a second principal plane that are positioned on sides opposite to each other in a thickness direction; and

a sensor unit located in the first principal plane of said basement layer,

said sensor unit comprising;

a drive frame disposed apart from said basement layer on the first principal plane of said basement layer;

a driving means for causing said drive frame to vibrate in a driving direction;

a Coriolis frame that is connected to said drive frame in the state of being disposed apart from said basement layer on said first principal plane of said basement layer, and that is vibrated in the driving direction with the same amplitude and in the same phase as those of the vibration of said drive frame, as well as vibrated by Coriolis force in a detection direction intersecting with said driving direction;

a detection frame that is connected to said Coriolis frame in the state of being disposed apart from said basement layer on said first principal plane of said basement layer, and is vibrated in the detection direction with the same amplitude and in the same phase of those of the vibration in the detection direction of said Coriolis frame;

a beam that is disposed apart form said basement layer on said first principal plane of said basement layer, and that fixes said detection frame to said basement layer so as not to be affected by the vibration in the driving direction of said Coriolis frame, and so as to follow the vibration in the detection direction of said Coriolis frame; and

a detection means for detecting the vibration in a detection direction of said detection frame as an applied angular rate;

wherein said detection frame is connected to a support disposed outside of said sensor unit via said beam and fixed to said basement layer.

2. The inertial sensor according to claim 1,

wherein said driving means is formed of an electrostatic comb-typed drive unit.

3. The inertial sensor according to claim 1,

wherein said detection means is formed of an electrostatic comb-typed detector.

4. The inertial sensor according to claim 1,

wherein said support is disposed on a first axis extending in a first direction on said first principal plane of said basement layer;

wherein said sensor unit includes two sensor units;

wherein said two sensor units are disposed so as to be symmetrical with respect to a point of said support on said first axis on said first principal plane of said basement layer; and

wherein said respective drive frames of said two sensor units are disposed so as to vibrate in inverted phases each other.

5. The inertial sensor according to claim 1,

wherein said support is disposed at an intersection of said first axis extending in the first direction on said first principal plane of said basement layer and a second axis extending in a second direction intersecting with said first axis;

wherein said sensor unit includes two first sensor units and two second sensor units;

wherein said two first sensor units are disposed symmetrically with respect to a point of said support on said first axis on said first principal plane of said basement layer;

wherein said respective drive frames of said two first sensor units are disposed so as to vibrate in inverted phase each other;

wherein the two second sensor units are disposed symmetrically about a point with respect to the support on the second axis on the first principal plane of the basement layer;

wherein said respective drive frames of said two second sensor units are disposed to vibrate in inverted phase each other; and

wherein said drive frames of said two first sensor units and the drive frames of said two second sensor units are disposed so as to operate in synchronization in the state in which phases are shifted by 90 degrees.

6. The inertial sensor according to claim 5,

wherein among said sensor units, drive frames of said first sensor unit and drive frames of said second sensor unit that are adjacent to each other are connected by a connection means.

7. The inertial sensor according to claim 6,

wherein a joint being a stationary point is located on said connection means.

8. The inertial sensor according to claim 7,

wherein said sensor unit is fixed to said basement layer with said joint and said support.

9. The inertial sensor according to claim 7,

wherein said joints opposed with respect to said support are connected to each other with a beam.

10. The inertial sensor according to claim 9,

wherein a support disposed outside of said connection means and said joint are connected with a spring interposed therebetween.

11. The inertial sensor according to claim 1,

wherein said sensor unit is made of a material selected from the group consisting of a conductive silicon, a conductive poly-silicon or a plated metal.

12. An inertial sensor comprising:

a basement layer including a first principal plane and a second principal plane that are positioned on sides opposite to each other in a thickness direction;

in said first principal plane of said basement layer, with cantering around an intersection of a first axis extending in a first direction and a second axis extending in a second direction intersecting with said first direction, two first sensor units disposed symmetrically about a point on said first axis and two second sensor units disposed symmetrically about a point on said second axis; and

a support located outside of said two first sensor units and said two second sensor units, and disposed at the intersection of said first axis and said second axis;

each of said two first sensor units and said two second sensor units comprising;

a drive frame disposed apart from said basement layer on said first principal plane of said basement layer;

a driving means for causing said drive frame to vibrate in a driving direction;

a Coriolis frame that is connected to said drive frame in the state of being disposed apart from said basement layer on said first principal plane of said basement layer, and that is vibrated in the driving direction with the same amplitude and in the same phase as those of the vibration of said drive frame, as well as vibrated by Coriolis force in a detection direction intersected with respect to the driving direction;

a detection frame that is connected to said Coriolis frame in the state of being disposed apart from said basement layer on said first principal plane of said basement layer, and is vibrated in the detection direction with the same amplitude and in the same phase of those of the vibration in the detection direction of said Coriolis frame;

a beam that is disposed apart form said basement layer on said first principal plane of said basement layer, and that supports said detection frame so as not to be affected by the vibration in the driving direction of said Coriolis frame, and so as to follow the vibration in the detection direction of said Coriolis frame; and

a detection means for detecting the vibration in the detection direction of said detection frame as an applied angular rate;

wherein said respective detection frames of said two first sensor units and said two second sensor units are connected to said support via said beam;

wherein said respective drive frames of said two first sensor units are disposed so as to vibrate in inverted phases each other;

wherein the respective drive frames of said two second sensor units are disposed so as to vibrate in inverted phases each other; and

wherein said drive frames of said two first sensor units and said drive frames of said two second sensor units are disposed so as to operate in synchronization in the state in which phases are shifted by 90 degrees.

13. The inertial sensor according to claim 12,

wherein among said two first sensor units and said two second sensor units, drive frames of said first sensor unit and drive frames of said second sensor unit that are adjacent to each other are connected by a connection means.

14. The inertial sensor according to claim 13,

wherein said connection means functions to cause said respective drive frames of said two second sensor units to move in a direction to get closer when said respective drive frames of said two first sensor units are moved in a direction to be apart with, and to cause said respective drive frames of said two second sensor units to move in a direction to be apart with when said respective drive frames of said two first sensor units are moved in a direction to get closer.

15. The inertial sensor according to claim 12,

wherein said support is fixed to said basement layer.

16. The inertial sensor according to claim 12,

wherein said support is not fixed to said basement layer.

17. An inertial sensor comprising:

a basement layer including a first principal plane and a second principal plane that are positioned on sides opposite to each other in a thickness direction;

in said first principal plane of said basement layer, with cantering around an intersection of a first axis extending in a first direction and a second axis extending in a second direction intersecting with said first direction, two first sensor units disposed symmetrically about a point on said first axis and two second sensor units disposed symmetrically about a point on said second axis; and

a support located outside of said two first sensor units and said two second sensor units, and disposed at the intersection of said first axis and said second axis;

each of said two first sensor units and said two second sensor units comprising;

a drive frame disposed apart from said basement layer on said first principal plane of said basement layer;

a driving means for causing said drive frame to vibrate in a driving direction;

a Coriolis frame that is connected to said drive frame in the state of being disposed apart from said basement layer on said first principal plane of said basement layer, and that is vibrated in the driving direction with the same amplitude and in the same phase as those of the vibration of said drive frame, as well as vibrated by Coriolis force in a detection direction intersected with respect to the driving direction;

a detection frame that is connected to said Coriolis frame in the state of being disposed apart from said basement layer on said first principal plane of said basement layer, and is vibrated in the detection direction with the same amplitude and in the same phase of those of the vibration in the detection direction of said Coriolis frame;

a beam that is disposed apart form said basement layer on said first principal plane of said basement layer, and that supports said detection frame so as not to be affected by the vibration in the driving direction of said Coriolis frame, and so as to follow the vibration in the detection direction of said Coriolis frame; and

a detection means for detecting the vibration in the detection direction of said detection frame as an applied angular rate;

wherein said respective detection frames of said two first sensor units and said two second sensor units are connected to said support via said beam;

wherein among said two first sensor units and said two second sensor units, drive frames of said first sensor unit and drive frames of said second sensor unit that are adjacent to each other are connected by a connection means;

wherein said respective drive frames of said two first sensor units are disposed so as to vibrate in inverted phases each other;

wherein the respective drive frames of said two second sensor units are disposed so as to vibrate in inverted phases each other; and

wherein said drive frames of said two first sensor units and said drive frames of said two second sensor units are disposed so as to operate in synchronization in the state in which phases are shifted by 90 degrees.

18. An inertial sensor comprising:

a basement layer including a first principal plane and a second principal plane that are positioned on sides opposite to each other in a thickness direction;

in said first principal plane of said basement layer, with cantering around an intersection of a first axis extending in a first direction and a second axis extending in a second direction intersecting with said first direction, two first sensor units disposed symmetrically about a point on said first axis and two second sensor units disposed symmetrically about a point on said second axis; and

a support located outside of said two first sensor units and said two second sensor units, and disposed at the intersection of said first axis and said second axis;

each of said two first sensor units and said two second sensor units comprising;

a drive frame disposed apart from said basement layer on said first principal plane of said basement layer;

a driving means for causing said drive frame to vibrate in a driving direction;

a Coriolis frame that is connected to said drive frame in the state of being disposed apart from said basement layer on said first principal plane of said basement layer, and that is vibrated in the driving direction with the same amplitude and in the same phase as those of the vibration of said drive frame, as well as vibrated by Coriolis force in a detection direction intersected with respect to the driving direction;

a detection frame that is connected to said Coriolis frame in the state of being disposed apart from said basement layer on said first principal plane of said basement layer, and is vibrated in the detection direction with the same amplitude and in the same phase of those of the vibration in the detection direction of said Coriolis frame;

a beam that is disposed apart form said basement layer on said first principal plane of said basement layer, and that supports said detection frame so as not to be affected by the vibration in the driving direction of said Coriolis frame, and so as to follow the vibration in the detection direction of said Coriolis frame; and

a detection means for detecting the vibration in the detection direction of said detection frame as an applied angular rate;

wherein said respective detection frames of said two first sensor units and said two second sensor units are connected to said support via said beam;

wherein among said two first sensor units and said two second sensor units, drive frames of said first sensor unit and drive frames of said second sensor unit that are adjacent to each other are connected by a connection means;

wherein a joint being a stationary point is disposed on said connection means;

wherein said joints opposed with respect to said support are connected to each other by a beam;

wherein said respective drive frames of said two first sensor units are disposed so as to vibrate in inverted phases each other;

wherein the respective drive frames of said two second sensor units are disposed so as to vibrate in inverted phases each other; and

wherein said drive frames of said two first sensor units and said drive frames of said two second sensor units are disposed so as to operate in synchronization in the state in which phases are shifted by 90 degrees.

19. The inertial sensor according to claim 18,

wherein said two first sensor units and said two second sensor units are fixed to said basement layer with said joint and said support.

20. An inertial sensor comprising:

a basement layer including a first principal plane and a second principal plane that are positioned on sides opposite to each other in a thickness direction;

in said first principal plane of said basement layer, with cantering around an intersection of a first axis extending in a first direction and a second axis extending in a second direction intersecting with said first direction, two first sensor units disposed symmetrically about a point on said first axis and two second sensor units disposed symmetrically about a point on said second axis; and

a support located outside of said two first sensor units and said two second sensor units, and disposed at the intersection of said first axis and said second axis;

each of said two first sensor units and said two second sensor units comprising;

a drive frame disposed apart from said basement layer on said first principal plane of said basement layer;

a driving means for causing said drive frame to vibrate in a driving direction;

a Coriolis frame that is connected to said drive frame in the state of being disposed apart from said basement layer on said first principal plane of said basement layer, and that is vibrated in the driving direction with the same amplitude and in the same phase as those of the vibration of said drive frame, as well as vibrated by Coriolis force in a detection direction intersected with respect to the driving direction;

a detection frame that is connected to said Coriolis frame in the state of being disposed apart from said basement layer on said first principal plane of said basement layer, and is vibrated in the detection direction with the same amplitude and in the same phase of those of the vibration in the detection direction of said Coriolis frame;

a beam that is disposed apart form said basement layer on said first principal plane of said basement layer, and that supports said detection frame so as not to be affected by the vibration in the driving direction of said Coriolis frame, and so as to follow the vibration in the detection direction of said Coriolis frame; and

a detection means for detecting the vibration in the detection direction of said detection frame as an applied angular rate;

wherein said respective detection frames of said two first sensor units and said two second sensor units are connected to said support via said beam;

wherein among said two first sensor units and said two second sensor units, drive frames of said first sensor unit and drive frames of said second sensor unit that are adjacent to each other are connected by a connection means;

wherein a joint being a stationary point is disposed on said connection means;

wherein said joints opposed with respect to said support are connected to each other by a beam;

wherein a support disposed more outward of the connection means and said joint are connected with a spring interposed therebetween;

wherein said respective drive frames of said two first sensor units are disposed so as to vibrate in inverted phases each other;

wherein the respective drive frames of said two second sensor units are disposed so as to vibrate in inverted phases each other; and

wherein said drive frames of said two first sensor units and said drive frames of said two second sensor units are disposed so as to operate in synchronization in the state in which phases are shifted by 90 degrees.