Mirror device including actuator controlled based on capacitance

Patent metadata

Field	Value
Publication number	US-10088672-B2
Application number	US-201314777061-A
Country	US
Kind code	B2
Filing date	Nov 25, 2013
Priority date	Mar 26, 2013
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

A mirror device includes a mirror, an actuator tilting the mirror, a first hinge coupling the mirror to the actuator, a base, a second hinge coupling the mirror to the base, a movable comb electrode coupled to the mirror, and a fixed comb electrode fixed to the base. The actuator is controlled based on a capacitance between the movable comb electrode and the fixed comb electrode. The movable comb electrode is disposed on a portion of the mirror closer to the second hinge than to the first hinge.

First claim

The invention claimed is:

1. A mirror device comprising:
a mirror including a mirror body, and a mirror surface layer stacked on a surface of the mirror body;
an actuator having an actuator body and a piezoelectric element stacked on a surface of the actuator body, wherein the piezoelectric element is configured to actuate the actuator body from a first position to a second position, and tilting the mirror;
a first hinge coupling a first side surface of the mirror body to the actuator, and curved when the mirror is tilted;
a base;
a second hinge directly coupling a second side surface of the mirror body to the base, and curved when the mirror is tilted;
a movable comb electrode coupled to the mirror; and
a fixed comb electrode fixed to the base, and facing the movable comb electrode, wherein
the first and second hinges are spaced apart from each other,
the actuator is controlled based on a capacitance between the movable comb electrode and the fixed comb electrode,
the movable comb electrode is disposed on a portion of the mirror closer to the second hinge than to the first hinge when viewed in plan, and
the actuator extends from the base.

2. The mirror device of claim 1 , wherein
the movable comb electrode is disposed on an opposite side of the mirror from the actuator.

3. The mirror device of claim 1 , wherein
stiffness of the second hinge is higher than that of the first hinge.

4. The mirror device of claim 1 , wherein
the mirror, the second hinge, and the movable comb electrode are arranged in sequence.

5. The mirror device of claim 1 , wherein
the mirror includes a plurality of the mirrors,
the actuator includes a plurality of actuators,
the first hinge includes a plurality of first hinges,
the second hinge includes a plurality of second hinges,
the movable comb electrode includes a plurality of movable comb electrodes,
the mirrors are disposed in a predetermined direction parallel to an axis about which each of the mirrors is tilted,
each of the mirrors is provided with at least associated one of the actuators, at least associated one of the first hinges, at least associated one of the second hinges, and at least associated one of the movable comb electrodes, and
the at least associated one of the actuators, the at least associated one of the first hinges, the each of the mirrors, the at least associated one of the second hinges, and the at least associated one of the movable comb electrodes are disposed in sequence in a direction orthogonal to the predetermined direction.

6. The mirror device of claim 1 , wherein
the mirror is tilted about an axis substantially passing through the second hinge, and
a portion of the mirror to which the first hinge is coupled is displaced in a direction intersecting with the surface of the mirror by operation of the actuator.

7. The mirror device of claim 1 , wherein
the movable comb electrode having a plurality of electrode fingers is coupled to the mirror through an arm, and
the arm intersects with an axis about which the mirror is tilted.

8. The mirror device of claim 1 , wherein
the mirror is tilted about an axis substantially passing through the second hinge,
a portion of the mirror to which the first hinge is coupled is displaced in a direction intersecting with the surface of the mirror by operation of the actuator,
the movable comb electrode having a plurality of electrode fingers is coupled to the mirror through an arm, and
the arm intersects with an axis about which the mirror is tilted.

9. A mirror device comprising:
a mirror including a mirror body, and a mirror surface layer stacked on a surface of the mirror body;
an actuator having an actuator body and a piezoelectric element stacked on a surface of the actuator body, wherein the piezoelectric element is configured to actuate the actuator body from a first position to a second position, and tilting the mirror;
a first hinge coupling a first side surface of the mirror body to the actuator, and curved when the mirror is tilted;
a base;
a second hinge directly coupling a second side surface of the mirror body to the base, and curved when the mirror is tilted;
a movable comb electrode coupled to the mirror;
a fixed comb electrode fixed to the base, and facing the movable comb electrode; and
a controller applying a voltage to the piezoelectric element based on a capacitance between the movable comb electrode and the fixed comb electrode to control the actuator, wherein
the actuator extends from the base,
the first and second hinges are spaced apart from each other,
the controller controls the actuator such that the mirror is tilted within a predetermined tilt range where the capacitance monotonically increases or decreases, and
an absolute value of a rate of a change in the capacitance relative to a tilt angle of the mirror is larger in a state where the mirror is tilted at a limiting angle closer to an initial state, where no voltage is applied to the mirror, within the tilt range than in the initial state.

10. The mirror device of claim 9 , wherein
the mirror is tilted about an axis substantially passing through the second hinge, and
a portion of the mirror to which the first hinge is coupled is displaced in a direction intersecting with the surface of the mirror by operation of the actuator.

11. The mirror device of claim 9 , wherein
the movable comb electrode having a plurality of electrode fingers is coupled to the mirror through an arm, and
the arm intersects with an axis about which the mirror is tilted.

12. The mirror device of claim 9 , wherein
the mirror is tilted about an axis substantially passing through the second hinge,
a portion of the mirror to which the first hinge is coupled is displaced in a direction intersecting with the surface of the mirror by operation of the actuator,
the movable comb electrode having a plurality of electrode fingers is coupled to the mirror through an arm, and
the arm intersects with an axis about which the mirror is tilted.

13. A mirror device comprising:
a mirror including a mirror body, and a mirror surface layer stacked on a surface of the mirror body;
an actuator having an actuator body and a piezoelectric element stacked on a surface of the actuator body, wherein the piezoelectric element is configured to actuate the actuator body from a first position to a second position, and tilting the mirror;
a first hinge coupling a first side surface of the mirror body to the actuator, and curved when the mirror is tilted;
a base;
a second hinge directly coupling a second side surface of the mirror body to the base, and curved when the mirror is tilted;
a movable comb electrode coupled to the mirror;
a fixed comb electrode fixed to the base, and facing the movable comb electrode; and
a controller applying a voltage to the piezoelectric element based on a capacitance between the movable comb electrode and the fixed comb electrode to control the actuator, wherein
the actuator extends from the base,
the first and second hinges are spaced apart from each other,
the mirror is tilted in an initial position where no voltage is applied to the piezoelectric element compared with a reference position where the capacitance reaches the maximum value, and
the controller applies a voltage to the piezoelectric element to tilt the mirror toward the opposite side of the reference position from the initial position within a predetermined tilt range where the capacitance monotonically increases or decreases on the opposite side.

14. The mirror device of claim 13 , wherein
the mirror is tilted about an axis substant

Assignees

• Sumitomo Precision Prod Co

Inventors

• Torayashiki Osamu
• Uchino Ryohei
• Misaki Tokiko

Classifications

• G02B26/0816 Primary

  by means of one or more reflecting elements · CPC title

• G02B6/356

  in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links (switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001) · CPC title

• G02B26/0858 Primary

  the reflecting means being moved or deformed by piezoelectric means · CPC title

• G02B6/3566

  involving bending a beam, e.g. with cantilever · CPC title

• G02B6/3586

  Control or adjustment details, e.g. calibrating (testing optical equipment G01M11/00) · CPC title