Physical quantity sensor, sensor device, electronic apparatus, and moving object

• US 10,352,701 B2
• Filed: 09/09/2016
• Issued: 07/16/2019
• Est. Priority Date: 09/15/2015
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Tanaka, Satoru
• Primary Examiner(s): Le, Son T
• Assistant Examiner(s): Roberts, Herbert K
• Application Number:
  US15/260,757
• Publication Number:
  US 20170074658A1
• Time in Patent Office: 1,040 Days
• CPC Class Codes: G01C 19/5755 the devices having a single sensing mass
• CPC Class Codes: G01C 19/5769 Manufacturing; Mounting; Housings
• 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
• CPC Class Codes: G01P 2015/0837 the mass being suspended so as to only allow movement perpendicular to the plane of the substrate, i.e. z-axis sensor
• CPC Class Codes: G01P 2015/0874 using means for preventing stiction of the seismic mass to the substrate

Abstract

A physical quantity sensor includes a base substrate, a movable portion that is oscillatably provided around an axis while facing the base substrate and that is divided into a first movable portion and a second movable portion, a first fixed electrode that is disposed on the base substrate facing the first movable portion, and a second fixed electrode that is disposed on the base substrate facing the second movable portion. The first fixed electrode and the second fixed electrode are configured so as to offset at least a part of a difference between a first fringe capacitance, which is between the first movable portion and the first fixed electrode, and a second fringe capacitance, which is between the second movable portion and the second fixed electrode.

Claims

1. A physical quantity sensor comprising:

a substrate;

a movable object that is oscillatably provided around a center of oscillation axis while facing the substrate and that is divided into a first movable portion and a second movable portion of which an area is larger than that of the first movable portion with the center of oscillation axis as a boundary in a plan view seen from a thickness direction of the substrate;

a first electrode that is disposed on the substrate facing the first movable portion and spaced apart from the center of oscillation axis; and

a second electrode that is disposed on the substrate facing the second movable portion and spaced apart from the center of oscillation axis,

wherein the first electrode and the second electrode are each configured to move the movable object, and each configured to generate a capacitance,

a distance at which the first electrode is spaced apart from the center of oscillation axis is equal to a distance at which the second electrode is spaced apart from the center of oscillation axis,

a width of the second electrode in a direction that is co-planar with the substrate and orthogonal to the oscillation axis is less than a width of the first electrode in said direction, and

the first electrode and the second electrode are configured so as to offset at least a part of a difference between a first fringe capacitance, which is between the first movable portion and the first electrode, and a second fringe capacitance, which is between the second movable portion and the second electrode.

2. The physical quantity sensor according to claim 1,

wherein the movable object includes a through hole that is provided at a position superimposed on an edge portion of the second electrode in a plan view and passing through the thickness direction of the movable object.

3. A sensor device comprising:

the physical quantity sensor according to claim 1; and

an electronic component that is electrically connected to the physical quantity sensor.

4. An electronic apparatus comprising:

the physical quantity sensor according to claim 1.

5. A moving object comprising:

the physical quantity sensor according to claim 1.

6. The physical quantity sensor according to claim 1, wherein an entirety of each of the first electrode and the second electrode are overlapped by the movable object in a plan view.

7. A physical quantity sensor comprising:

a substrate;

a movable object that is oscillatably provided around a center of oscillation axis while facing the substrate and that is divided into a first movable portion and a second movable portion of which an area is larger than that of the first movable portion with the center of oscillation axis as a boundary in a plan view seen from a thickness direction of the substrate;

a first electrode that is disposed on the substrate facing the first movable portion and spaced apart from the center of oscillation axis; and

a second electrode that is disposed on the substrate facing the second movable portion and spaced apart from the center of oscillation axis,

wherein the first electrode and the second electrode are each configured to move the movable object, and each configured to generate a capacitance,

a distance at which the first electrode is spaced apart from the center of oscillation axis is equal to a distance at which the second electrode is spaced apart from the center of oscillation axis,

a width of the second electrode in a direction that is co-planar with the substrate and orthogonal to the oscillation axis is less than a width of the first electrode in said direction such that an area of a first region in which the first movable portion and the first electrode are superimposed on each other is larger than an area of a second region in which the second movable portion and the second electrode are superimposed on each other in a plan view.

8. The physical quantity sensor according to claim 7,

wherein an end of the first electrode at the opposite side of the center of oscillation axis in a plan view is positioned at an outer side of the first region.

9. The physical quantity sensor according to claim 7,

wherein an end of the first electrode at the opposite side of the center of oscillation axis in a plan view is positioned at an outer side of the first region.

10. The physical quantity sensor according to claim 7,

wherein the movable object includes a through hole that is provided at a position superimposed on an edge portion of the second electrode in a plan view and passing through the thickness direction of the movable object.

11. The physical quantity sensor according to claim 7,

wherein a length of the second movable portion in a direction orthogonal to the center of oscillation axis in a plan view is longer than a length of the first movable portion.

12. A sensor device comprising:

the physical quantity sensor according to claim 7; and

an electronic component that is electrically connected to the physical quantity sensor.

13. An electronic apparatus comprising:

the physical quantity sensor according to claim 7.

14. A moving object comprising:

the physical quantity sensor according to claim 7.