Inertial Sensor

• US 20140007685A1
• Filed: 06/28/2013
• Published: 01/09/2014
• Est. Priority Date: 07/06/2012
• Status: Active Grant

• Current Assignee: Hitachi Astemo Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Inventors: JEONG, Heewon, ZHANG, Yuhua, YAMANAKA, Kiyoko, HAYASHI, Masahide
• Granted Patent: US 9,970,956 B2
• Time in Patent Office: Days
• US Class Current: 73/514.32
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0831 the mass being of the paddle type having the pivot axis between the longitudinal ends of the mass, e.g. see-saw configuration

Abstract

A movable part rotates about a rotation axis, which passes through a support, when an inertial force in a detecting direction is applied to an inertial sensor. The movable part includes a first region and a second region displaced in a direction opposite to a direction of the first region when the inertial force is applied. A second substrate includes first and second detection electrodes opposed to the first and second regions, respectively. The first detection electrode and the second detection electrode are provided symmetrically with respect to the rotation axis. A cavity is provided symmetrically with respect to the rotation axis. In a direction perpendicular to the detecting direction and a direction in which the rotation axis extends, a length from the rotation axis to an end of the first region and a length from the rotation axis to an end of the second region are different.

Claims

1. An inertial sensor including a movable part in a cavity surrounded by a first substrate, a second substrate provided above the first substrate, and a sidewall,

the inertial sensor comprising a support provided in contact with the first substrate and the second substrate to support the movable part, wherein

the movable part is a movable part configured to rotate about a rotation axis, which passes through the support, when an inertial force in a detecting direction is applied to the inertial sensor, the movable part including a first region and a second region displaced in a direction opposite to a direction of the first region when the inertial force is applied,

the second substrate includes a first detection electrode opposed to the first region and a second detection electrode opposed to the second region,

the first detection electrode and the second detection electrode are provided symmetrically with respect to the rotation axis,

the cavity is provided symmetrically with respect to the rotation axis, and

in a direction perpendicular to the detecting direction and a direction in which the rotation axis extends, a length from the rotation axis to an end of the first region and a length from the rotation axis to an end of the second region are different.

2. The inertial sensor according to claim 1, wherein

the length from the rotation axis to the end of the second region is larger than the length from the rotation axis to the end of the first region, and

the second substrate further includes a diagnosis electrode opposed to the second region and used during a diagnosis of the inertial sensor.

3. The inertial sensor according to claim 1, further comprising a mold resin package set in contact with the second substrate.

4. The inertial sensor according to claim 1, wherein the first substrate, the second substrate, and the movable part are formed of silicon.

5. The inertial sensor according to claim 1, wherein the inertial force is acceleration in the detecting direction.

6. An inertial sensor including first and second movable parts in a cavity surrounded by a first substrate, a second substrate provided above the first substrate, and a sidewall,

the inertial sensor comprising a support provided in contact with the first substrate and the second substrate to support the first movable part,

the first movable part is a movable part configured to rotate about a rotation axis, which passes through the support, when an inertial force in a detecting direction is applied to the inertial sensor, the first movable part including a first region connected to the second movable part via an elastic beam and a second region displaced in a direction opposite to a direction of the first region when the inertial force is applied,

the second substrate includes a first detection electrode opposed to the first region and a second detection electrode opposed to the second region,

the first detection electrode and the second detection electrode are provided symmetrically with respect to the rotation axis, and

the cavity is provided symmetrically with respect to the rotation axis.

7. The inertial sensor according to claim 6, wherein the second substrate further includes a first diagnosis electrode opposed to the second movable part and used during a diagnosis of the inertial sensor.

8. The inertial sensor according to claim 7, wherein

the second substrate further includes a second diagnosis electrode opposed to the second movable part and used during the diagnosis of the inertial sensor, and

the first diagnosis electrode and the second diagnosis electrode are provided symmetrically with respect to the rotation axis.

9. The inertial sensor according to claim 6, wherein the first movable part and the second movable part are provided symmetrically with respect to the rotation axis.

10. The inertial sensor according to claim 6, wherein

the first movable part is provided symmetrically with respect to the rotation axis, and

the second movable part is provided asymmetrically with respect to the rotation axis.

11. The inertial sensor according to claim 6, further comprising a mold resin package set in contact with the second substrate.

12. The inertial sensor according to claim 6, wherein the first substrate, the second substrate, the first movable part, and the second movable part are formed of silicon.

13. An inertial sensor including a movable part in a cavity surrounded by a first substrate, a second substrate provided above the first substrate, and a sidewall,

the inertial sensor comprising:

a first support provided in contact with the first substrate and the second substrate to support the movable part; and

a second support provided in contact with the first substrate and the second substrate and not in contact with the movable part, wherein

the movable part is a movable part configured to rotate about a rotation axis, which passes through the first support, when an inertial force in a detecting direction is applied to the inertial sensor, the movable part including a first region and a second region displaced in a direction opposite to a direction of the first region when the inertial force is applied,

the second substrate includes a first detection electrode opposed to the first region and a second detection electrode opposed to the second region,

the first detection electrode and the second detection electrode are provided symmetrically with respect to the rotation axis, and

in a direction perpendicular to the detecting direction and the rotation axis, a length from the rotation axis to an end of the first region and a length from the rotation axis to an end of the second region are different.

14. The inertial sensor according to claim 13, wherein the cavity is provided asymmetrically with respect to the rotation axis.

15. The inertial sensor according to claim 13, wherein the inertial force is acceleration in the detecting direction.