Electrostatic vibration device

• US 7,062,970 B2
• Filed: 11/24/2003
• Issued: 06/20/2006
• Est. Priority Date: 01/14/2003
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Higuchi, Hirofumi
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US10/718,630
• Publication Number:
  US 20040135466A1
• Time in Patent Office: 939 Days
• Field of Search: 735/041.2, 735/041.4, 310/309, 331/154
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: H02N 1/008 Laterally driven motors, e.g. of the comb-drive type

Abstract

A vibrator has a frame portion having a planar frame shape, an in-frame fixed portion which is fixed to a base portion and located in the inner space surrounded by the inner periphery of the frame portion, and a driving electrode comprising a first driving electrode disposed so as to confront the outer peripheral portion of the vibrator, and a second driving electrode which is equipped to the in-frame fixed portion so as to confront the inner peripheral portion of the frame portion, and the back-side portion of the in-frame fixed portion and the inner peripheral portion of the frame portion confronting the back-side portion are designed in an unevenly-shaped portion.

Claims

1. A device having a vibrator that is driven electrostatically, the device comprising:

a substrate;

a vibrator movably supported by the substrate so as to vibrate in a predetermined direction, wherein the vibrator includes a frame portion having a planar frame shape;

an in-frame fixed portion that is fixed to the substrate and located in an inner space surrounded by an inner peripheral portion of the frame portion; and

a driving electrode for applying electrostatic force to the vibrator to drive the vibrator so that the vibrator vibrates in the predetermined direction, wherein the driving electrode comprises;

a first driving electrode disposed to confront an outer peripheral portion of the vibrator; and

a second driving electrode disposed on a first side of the in-frame fixed portion and disposed so as to confront the inner peripheral portion of the frame portion, the second driving electrode being further electrically connected to the first driving electrode to cooperatively apply the electrostatic force to the vibrator in a same direction as the first driving electrode,

wherein at least one of a portion of the in-frame fixed portion located opposite to the first side on which the second driving electrode is disposed, and a side portion of the inner peripheral portion of the frame portion confronting the second side portion of the in-frame fixed portion is designed to have an unevenly-shaped portion.

2. The device according to the claim 1, wherein both the second side portion of the in-frame fixed portion and the side portion of the inner peripheral portion of the frame portion which confronts the second side portion are designed to have the unevenly-shaped portion.

3. The device according to claim 2, wherein the unevenly-shaped portion of the second side portion of the in-frame fixed portion and the unevenly-shaped portion of the inner peripheral portion of the frame portion which confronts the second side portion are arranged to be displaced from each other in phase.

4. The device according to claim 2, wherein the unevenly-shaped portion of the second side portion of the in-frame fixed portion and the unevenly-shaped portion of the inner peripheral portion of the frame portion have a shape selected from a group consisting of a planar rectangular shape, a triangular shape, a trapezoidal shape, a semi-circular shape and a saw-tooth shape.

5. The device according to claim 1, wherein the frame portion is partially cut out to form a notch portion in the frame portion, and the in-frame fixed portion extends from the substrate through the notch portion into the inner peripheral portion of the frame portion.

6. A device having a vibrator that is driven electrostatically, the device comprising:

a substrate;

a vibrator movably supported by the substrate so as to vibrate in a predetermined direction, wherein the vibrator includes a frame portion having a planar frame shape;

an in-frame fixed portion that is fixed to the substrate and located in an inner space surrounded by an inner peripheral portion of the frame portion; and

a driving electrode for applying electrostatic force to the vibrator to drive the vibrator so that the vibrator vibrates in the predetermined direction, wherein the driving electrode comprises;

a first driving electrode disposed to confront an outer peripheral portion of the vibrator; and

a second driving electrode equipped to a first side of the in-frame fixed portion and disposed to confront the inner peripheral portion of the frame portion,

wherein at least one of a second side portion of the in-frame fixed portion located opposite to the side on which the second driving electrode is disposed, and a side portion of the inner peripheral portion of the frame portion confronting the second side portion of the in-frame fixed portion has an unevenly-shaped portion, and wherein the frame portion is partially cut out to form a notch portion in the frame portion, and the in-frame fixed portion extends from the substrate through the notch portion into the inner peripheral portion of the frame portion.

7. A device having a vibrator that is driven electrostatically, the device comprising:

a substrate;

a vibrator movably supported by the substrate, the vibrator being driven by an electrostatic force being applied thereto and comprising a frame portion having a planar frame shape; and

an in-frame fixed portion that is fixed to the substrate and located in an inner space surrounded by an inner peripheral portion of the frame portion, wherein the in-frame fixed portion has a side portion and the inner peripheral portion has a side portion, wherein a capacitor is generated between the side portion of the in-frame fixed portion and the side portion of the inner peripheral portion, wherein at least one of the side portion of the in-frame fixed portion and the side portion of the inner peripheral portion of the frame portion confronting the side portion of the in-frame fixed portion is designed to have an unevenly-shaped portion so that an electrostatic force to be generated in the capacitor is smaller than the electrostatic force for driving the vibrator.

8. The device according to claim 7, wherein both the side portion of the in-frame fixed portion and the side portion of the inner peripheral portion of the frame portion are designed to have the unevenly-shaped portion.

9. The device according to claim 8, wherein the unevenly-shaped portion of the side portion of the in-frame fixed portion and the unevenly-shaped portion of the inner peripheral portion of the frame portion are arranged to be displaced from each other in phase.

10. The device according to claim 8, wherein the unevenly-shaped portion of the side portion of the in-frame fixed portion and the unevenly-shaped portion of the inner peripheral portion of the frame portion have a shape selected from a group consisting of a planar rectangular shape, a triangular shape, a trapezoidal shape, a semi-circular shape and a saw-tooth shape.

11. A device having a vibrator driven electrostatically, comprising:

a substrate;

a vibrator movably supported by the substrate being movable in a predetermined direction, the vibrator comprising a first movable electrode and a second movable electrode equipotentially displaced from the first movable electrode;

a first driving electrode disposed to face the first movable electrode to form a first capacitor for applying electrostatic force to the vibrator to drive the vibrator in one direction along the predetermined direction; and

a second driving electrode disposed between the first movable electrode and the second movable electrode, and equipotentially provided to the first driving electrode, wherein the second driving electrode faces the second movable electrode to form a second capacitor for cooperatively applying electrostatic force to the vibrator with the first capacitor to drive the vibrator in the predetermined direction;

wherein at least one of a side portion of the first movable electrode at an opposite side of the first driving electrode, and a side portion of the second driving electrode at an opposite side of the second movable electrode has an unevenly shaped portion.

12. The device according to claim 11, wherein both the side portion of the first movable electrode and the side portion of the second driving electrode have the unevenly shaped portion.

13. The device according to claim 12, wherein the unevenly-shaped portion of the first movable electrode and the unevenly shaped portion of the second driving electrode are arranged to be displaced from each other in phase.

14. The device according to claim 12, wherein the unevenly-shaped portion of the first movable electrode and the unevenly shaped portion of the second driving electrode have a shape selected from a group consisting of a planar rectangular shape, a triangular shape, a trapezoidal shape, a semi-circular shape and a saw-tooth shape.