JP2014021189A

JP2014021189A - Rotary actuator

Info

Publication number: JP2014021189A
Application number: JP2012157489A
Authority: JP
Inventors: Makoto Hashizume; 誠橋爪; Fumiki Hyodo; 文紀兵藤; Yasushi Sawada; 廉士澤田; Noriaki Ishikawa; 範明石河; Yukinori Kawamura; 幸則河村; Takeshi Suzuki; 健鈴木
Original assignee: Kyushu University NUC; Fuji Electric Co Ltd
Current assignee: Kyushu University NUC; Fuji Electric Co Ltd
Priority date: 2012-07-13
Filing date: 2012-07-13
Publication date: 2014-02-03
Anticipated expiration: 2032-07-13
Also published as: JP6037691B2

Abstract

PROBLEM TO BE SOLVED: To enable both of a rotation direction and rotation angle of a movable electrode to be detected, and prevent detection accuracy of rotation angle from lowering.SOLUTION: In a rotary actuator, a holding member 130 attaches a movable electrode 120 to a frame body 110 and serves as an axle of the movable electrode 120. Fixed electrodes 140 each are opposite to the movable electrode 120 in plan view. A first detection electrode 150 is insulated from the movable electrode 120 and the fixed electrodes 140, and is opposite to one side of the movable electrode 120 in plan view. A second detection electrode 410 is insulated from the movable electrode 120 and the fixed electrodes 140, and at least a part thereof overlaps with the movable electrode 120 in plan view.

Description

本発明は、回転型アクチュエータに関する。 The present invention relates to a rotary actuator.

回転型アクチュエータは、例えば光スキャナーなどにおいて光の方向を変えるために用いられている。このような用途の回転型アクチュエータは、可動部である可動電極と、固定電極と、検出用電極を有している。可動電極は、可動電極と固定電極の間に印加される電圧によって揺動する。可動電極の回転角度は、可動電極と検出用電極の間に生じる静電容量の変化に基づいて検出される（例えば特許文献１，２参照） The rotary actuator is used to change the direction of light in, for example, an optical scanner. The rotary actuator for such applications has a movable electrode that is a movable part, a fixed electrode, and a detection electrode. The movable electrode is oscillated by a voltage applied between the movable electrode and the fixed electrode. The rotation angle of the movable electrode is detected based on a change in capacitance generated between the movable electrode and the detection electrode (see, for example, Patent Documents 1 and 2).

特に特許文献２に記載の技術では、可動電極と検出用電極が厚さ方向にずれて配置されている。このため、可動電極と検出用電極の間に生じる静電容量の変化に基づいて、可動電極の回転方向も検出できる。 In particular, in the technique described in Patent Document 2, the movable electrode and the detection electrode are arranged so as to be shifted in the thickness direction. For this reason, the rotational direction of the movable electrode can also be detected based on the change in capacitance generated between the movable electrode and the detection electrode.

特開２００５−２０８２５１号公報JP-A-2005-208251 特開２００４−１０９５８０号公報JP 2004-109580 A

特許文献２に記載の技術では、可動電極と検出用電極の間に生じる静電容量の変化が小さくなるため、回転角度の検出精度が低くなってしまう。 In the technique described in Patent Document 2, since the change in capacitance generated between the movable electrode and the detection electrode is small, the detection accuracy of the rotation angle is low.

本発明は上記事情に鑑みてなされたものであり、その目的とするところは、可動電極の回転方向及び回転角度の双方を検出することができ、かつ回転角度の検出精度が低くなることを抑制できる回転型アクチュエータを提供することにある。 The present invention has been made in view of the above circumstances, and an object of the present invention is to detect both the rotation direction and the rotation angle of the movable electrode and to suppress the detection accuracy of the rotation angle from being lowered. An object of the present invention is to provide a rotary actuator that can be used.

本発明によれば、回転型アクチュエータは、可動電極、枠体、保持部材、固定電極、第１検出電極、及び第２検出電極を備えている。保持部材は、可動電極を枠体に取り付けており、また、可動電極の回転軸となる。固定電極は、平面視で可動電極に対向している。第１検出用電極は、可動電極及び固定電極から絶縁されており、平面視において可動電極の一辺に対向している。第２検出用電極は、可動電極及び固定電極から絶縁されており、平面視において可動電極と少なくとも一部が重なっている。 According to the present invention, the rotary actuator includes a movable electrode, a frame, a holding member, a fixed electrode, a first detection electrode, and a second detection electrode. The holding member has the movable electrode attached to the frame body, and serves as a rotation axis of the movable electrode. The fixed electrode is opposed to the movable electrode in plan view. The first detection electrode is insulated from the movable electrode and the fixed electrode, and faces one side of the movable electrode in plan view. The second detection electrode is insulated from the movable electrode and the fixed electrode, and at least partially overlaps the movable electrode in plan view.

本発明によれば、可動電極の回転方向及び回転角度の双方を検出することができ、かつ回転角度の検出精度が低くなることを抑制できる。 According to the present invention, it is possible to detect both the rotation direction and the rotation angle of the movable electrode, and it is possible to suppress the detection accuracy of the rotation angle from being lowered.

実施形態に係る回転型アクチュエータの構成を示す平面図である。It is a top view which shows the structure of the rotary actuator which concerns on embodiment. 図１のＡ−Ａ´断面図である。It is AA 'sectional drawing of FIG. 図１の変形例を示す平面図である。It is a top view which shows the modification of FIG. 回転型アクチュエータの製造方法を示すための断面図である。It is sectional drawing for showing the manufacturing method of a rotary actuator. 回転型アクチュエータの製造方法を示すための断面図である。It is sectional drawing for showing the manufacturing method of a rotary actuator. 可動電極の回転角度と、可動電極と第１検出用電極の間に生じる静電容量との関係を示す図である。It is a figure which shows the relationship between the rotation angle of a movable electrode, and the electrostatic capacitance which arises between a movable electrode and the 1st electrode for a detection. 可動電極の回転角度と、可動電極と第２検出用電極の間に生じる静電容量との関係を示す図である。It is a figure which shows the relationship between the rotation angle of a movable electrode, and the electrostatic capacitance which arises between a movable electrode and the 2nd electrode for a detection. 可動電極を１ｋＨｚで±５°の範囲で振動させたときの、可動電極と第１検出用電極の間の静電容量の変化を示す図である。It is a figure which shows the change of the electrostatic capacitance between a movable electrode and the 1st electrode for a detection when a movable electrode is vibrated in the range of +/- 5 degree at 1 kHz. 可動電極を１ｋＨｚで±５°の範囲で振動させたときの、可動電極と第２検出用電極の間の静電容量の変化を示す図である。It is a figure which shows the change of the electrostatic capacitance between a movable electrode and the 2nd electrode for a detection when a movable electrode is vibrated in the range of +/- 5 degree at 1 kHz.

以下、本発明の実施の形態について、図面を用いて説明する。尚、すべての図面において、同様な構成要素には同様の符号を付し、適宜説明を省略する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

図１は、実施形態に係る回転型アクチュエータ１００の構成を示す平面図である。図２は、図１のＡ−Ａ´断面図である。ただし図２において、説明のため、保持部材１３０も点線で図示している。回転型アクチュエータ１００は、枠体１１０、保持部材１３０、可動電極１２０、固定電極１４０、第１検出用電極１５０、及び第２検出用電極４１０を備えている。保持部材１３０は、可動電極１２０を枠体１１０に取り付けており、かつ可動電極１２０の回転軸となる。固定電極１４０は、平面視で可動電極１２０に対向している。第１検出用電極１５０は、可動電極１２０及び固定電極１４０から絶縁されており、平面視において可動電極１２０の一辺に対向している。第２検出用電極４１０は、可動電極１２０及び固定電極１４０から絶縁されており、平面視において可動電極１２０と少なくとも一部が重なっている。以下、詳細に説明する。 FIG. 1 is a plan view showing a configuration of a rotary actuator 100 according to the embodiment. 2 is a cross-sectional view taken along the line AA ′ of FIG. However, in FIG. 2, the holding member 130 is also shown by a dotted line for explanation. The rotary actuator 100 includes a frame 110, a holding member 130, a movable electrode 120, a fixed electrode 140, a first detection electrode 150, and a second detection electrode 410. The holding member 130 has the movable electrode 120 attached to the frame 110 and serves as a rotation axis of the movable electrode 120. The fixed electrode 140 faces the movable electrode 120 in plan view. The first detection electrode 150 is insulated from the movable electrode 120 and the fixed electrode 140, and faces one side of the movable electrode 120 in plan view. The second detection electrode 410 is insulated from the movable electrode 120 and the fixed electrode 140, and at least partially overlaps the movable electrode 120 in plan view. Details will be described below.

図１に示すように、可動電極１２０の平面形状は矩形である。そして固定電極１４０は、平面視で可動電極１２０を挟むように２つ設けられている。可動電極１２０のうち固定電極１４０と対向する辺（図１においてＸ方向に伸びている辺）は、櫛歯形状となっている。枠体１１０は、可動電極１２０の４辺のうち固定電極１４０と対向していない２つの辺（図１においてＹ方向に伸びている辺）それぞれに対向している。 As shown in FIG. 1, the planar shape of the movable electrode 120 is a rectangle. Two fixed electrodes 140 are provided so as to sandwich the movable electrode 120 in plan view. A side of the movable electrode 120 facing the fixed electrode 140 (side extending in the X direction in FIG. 1) has a comb shape. The frame body 110 faces each of two sides (sides extending in the Y direction in FIG. 1) that do not face the fixed electrode 140 among the four sides of the movable electrode 120.

固定電極１４０のうち可動電極１２０と対向する辺は、櫛歯形状となっており、可動電極１２０の櫛歯部分とかみ合っている。このため、固定電極１４０と可動電極１２０は、互いに対向する部分の面積が大きくなり、その結果、可動電極１２０の駆動力は大きくなる。 A side of the fixed electrode 140 facing the movable electrode 120 has a comb-teeth shape and meshes with a comb-teeth portion of the movable electrode 120. For this reason, the area of the part which the fixed electrode 140 and the movable electrode 120 mutually oppose becomes large, As a result, the driving force of the movable electrode 120 becomes large.

保持部材１３０は、可動電極１２０のうち枠体１１０と対向している２辺それぞれに対して設けられている。詳細には、保持部材１３０は、可動電極１２０のうち枠体１１０と対向している辺の中心に接続している。そして２つの保持部材１３０を結ぶ線が、可動電極１２０の回転軸となっている。本実施形態では、枠体１１０、可動電極１２０、及び保持部材１３０は一体的に形成されている。 The holding member 130 is provided for each of the two sides of the movable electrode 120 facing the frame 110. Specifically, the holding member 130 is connected to the center of the side of the movable electrode 120 facing the frame 110. A line connecting the two holding members 130 is a rotation axis of the movable electrode 120. In the present embodiment, the frame 110, the movable electrode 120, and the holding member 130 are integrally formed.

第１検出用電極１５０は、固定電極１４０と並んでおり、可動電極１２０のうち固定電極１４０と対向している辺に対向している。本図に示す例では、固定電極１４０は、可動電極１２０の辺の中心部分に対向している。そして第１検出用電極１５０は、固定電極１４０を挟むように設けられており、可動電極１２０の辺の両端それぞれに対向している。固定電極１４０は、第１検出用電極１５０よりも大きい。本図に示す例では、第１検出用電極１５０は、可動電極１２０のうち対向する２辺に設けられている。すなわち第１検出用電極１５０は、保持部材１３０を基準として線対称となるように設けられている。ただし、第１検出用電極１５０は、可動電極１２０の一辺にのみ設けられていても良い。本実施形態において第１検出用電極１５０は、可動電極１２０の回転角度を検出するために用いられる。 The first detection electrode 150 is aligned with the fixed electrode 140, and faces the side of the movable electrode 120 that faces the fixed electrode 140. In the example shown in the figure, the fixed electrode 140 faces the central portion of the side of the movable electrode 120. The first detection electrode 150 is provided so as to sandwich the fixed electrode 140 and is opposed to both ends of the side of the movable electrode 120. The fixed electrode 140 is larger than the first detection electrode 150. In the example shown in this drawing, the first detection electrode 150 is provided on two opposing sides of the movable electrode 120. That is, the first detection electrode 150 is provided so as to be line-symmetric with respect to the holding member 130. However, the first detection electrode 150 may be provided only on one side of the movable electrode 120. In the present embodiment, the first detection electrode 150 is used to detect the rotation angle of the movable electrode 120.

図１に示す例において、第２検出用電極４１０は、全体が、平面視で可動電極１２０と重なっている。ただし、図３に示すように、第２検出用電極４１０の一部のみが可動電極１２０と重なっていても良い。また図１及び図３のいずれの例においても、平面視において第２検出用電極４１０は保持部材１３０と重なっていない。このようにすると、第２検出用電極４１０と可動電極１２０の間に生じる静電容量は、可動電極１２０の回転方向によって大きく変わる。このため、可動電極１２０の回転方向を精度良く検出できる。 In the example shown in FIG. 1, the second detection electrode 410 entirely overlaps the movable electrode 120 in plan view. However, as shown in FIG. 3, only a part of the second detection electrode 410 may overlap the movable electrode 120. In both examples of FIGS. 1 and 3, the second detection electrode 410 does not overlap the holding member 130 in plan view. In this way, the capacitance generated between the second detection electrode 410 and the movable electrode 120 varies greatly depending on the rotation direction of the movable electrode 120. For this reason, the rotation direction of the movable electrode 120 can be accurately detected.

図２に示すように、枠体１１０の下面、第１検出用電極１５０の下面、及び固定電極１４０の下面は、絶縁層３２０を介して基板３１０によって支持されている。これに対して可動電極１２０、及び保持部材１３０のうち少なくとも可動電極１２０に接続している部分は、上面及び下面のいずれも支持されていない。 As shown in FIG. 2, the lower surface of the frame 110, the lower surface of the first detection electrode 150, and the lower surface of the fixed electrode 140 are supported by the substrate 310 via the insulating layer 320. On the other hand, neither the upper surface nor the lower surface of the movable electrode 120 and the holding member 130 connected to at least the movable electrode 120 is supported.

また、第２検出用電極４１０は、絶縁板４００（第１保持部材）の上に形成されている。絶縁板４００は、平面視で可動電極１２０と重なっている。絶縁板４００上には配線も形成されている。この配線は、第２検出用電極４１０と制御部２００（後述）とを接続するために用いられている。 The second detection electrode 410 is formed on the insulating plate 400 (first holding member). The insulating plate 400 overlaps the movable electrode 120 in plan view. Wiring is also formed on the insulating plate 400. This wiring is used to connect the second detection electrode 410 and the control unit 200 (described later).

絶縁板４００は、基板３１０（第２保持部材）に接合されている。絶縁板４００と基板３１０の接合は、例えば陽極接合又は金属接合によって行われる。陽極接合を行う場合、絶縁板４００は、例えばガラス基板である。また金属接合を行う場合、絶縁板４００のうち基板３１０に対向する面、及び基板３１０のうち絶縁板４００に対向する面には金属層が形成される。これら２つの金属層は、例えばいずれも金であっても良いし、一方が金で他方が錫であってもよい。 The insulating plate 400 is bonded to the substrate 310 (second holding member). The insulating plate 400 and the substrate 310 are bonded by, for example, anodic bonding or metal bonding. When performing anodic bonding, the insulating plate 400 is, for example, a glass substrate. When metal bonding is performed, a metal layer is formed on a surface of the insulating plate 400 facing the substrate 310 and a surface of the substrate 310 facing the insulating plate 400. For example, both of these two metal layers may be gold, or one may be gold and the other may be tin.

また絶縁板４００と第２検出用電極４１０の接合は、接着剤を用いて行われても良い。この場合、接着剤としては、例えば光硬化型の接着剤が用いられても良いし、熱硬化型の接着剤が用いられても良い。または、絶縁板４００上にスパッタ等で導電膜を形成し、この導電膜を選択的に除去することで第２検出用電極４１０を形成してもよい。 The insulating plate 400 and the second detection electrode 410 may be joined using an adhesive. In this case, as the adhesive, for example, a photocurable adhesive may be used, or a thermosetting adhesive may be used. Alternatively, the second detection electrode 410 may be formed by forming a conductive film on the insulating plate 400 by sputtering or the like and selectively removing the conductive film.

回転型アクチュエータ１００の可動電極１２０は、例えば上面が鏡面になっている。この鏡面は、例えば可動電極１２０の上面に金属膜（例えばＡｌ膜）を形成することにより、形成されている。そして可動電極１２０の角度を変えることにより、可動電極１２０に入射してきた光の反射角を変える。回転型アクチュエータ１００は、例えば光スキャナーやモーションセンサに用いられる。 The movable electrode 120 of the rotary actuator 100 has, for example, a mirror surface on the upper surface. This mirror surface is formed, for example, by forming a metal film (for example, an Al film) on the upper surface of the movable electrode 120. Then, by changing the angle of the movable electrode 120, the reflection angle of the light incident on the movable electrode 120 is changed. The rotary actuator 100 is used for, for example, an optical scanner or a motion sensor.

また本実施形態において、回転型アクチュエータ１００は制御部２００を有している。制御部２００は、可動電極１２０の動きを制御する。具体的には、可動電極１２０を回転させるとき、制御部２００は、可動電極１２０と固定電極１４０の間に、交流電圧と直流電圧とを重畳させた電圧を印加する。これにより、可動電極１２０は回転する。 In the present embodiment, the rotary actuator 100 includes a control unit 200. The control unit 200 controls the movement of the movable electrode 120. Specifically, when rotating the movable electrode 120, the control unit 200 applies a voltage in which an AC voltage and a DC voltage are superimposed between the movable electrode 120 and the fixed electrode 140. Thereby, the movable electrode 120 rotates.

また、詳細を後述するように、制御部２００は、第１検出用電極１５０と可動電極１２０の間に生じる静電容量の変化に基づいて、可動電極１２０の回転角度を検出し、また、第２検出用電極４１０と可動電極１２０の間に生じる静電容量の変化に基づいて、可動電極１２０の回転方向を検出する。そして制御部２００は、これらの検出結果に基づいて、可動電極１２０と固定電極１４０の間に印加する電圧を制御する。従って、制御部２００は、可動電極１２０の回転方向及び角度を所望の値に制御することができる。 In addition, as will be described in detail later, the control unit 200 detects the rotation angle of the movable electrode 120 based on the change in capacitance generated between the first detection electrode 150 and the movable electrode 120, and the first 2 Based on a change in capacitance generated between the detection electrode 410 and the movable electrode 120, the rotational direction of the movable electrode 120 is detected. The control unit 200 controls the voltage applied between the movable electrode 120 and the fixed electrode 140 based on these detection results. Therefore, the control unit 200 can control the rotation direction and angle of the movable electrode 120 to desired values.

なお図１に示す例では、第１検出用電極１５０は、可動電極１２０のうち互いに対向する２辺に設けられている。このような場合、制御部２００は、一方の辺に設けられた第１検出用電極１５０のみを用いて、可動電極１２０の回転方向を判断する。 In the example shown in FIG. 1, the first detection electrode 150 is provided on two sides of the movable electrode 120 facing each other. In such a case, the control unit 200 determines the rotation direction of the movable electrode 120 using only the first detection electrode 150 provided on one side.

図４及び図５の各図は、回転型アクチュエータ１００の製造方法を示すための断面図である。これらの各図は、図１のＡ−Ａ´断面に相当している。 Each of FIGS. 4 and 5 is a cross-sectional view for illustrating a method for manufacturing the rotary actuator 100. Each of these figures corresponds to the AA ′ cross section of FIG.

まず、図４（ａ）に示すように、基板３１０上に絶縁層３２０及び導電層３３０を形成したものを準備する。基板３１０、絶縁層３２０、及び導電層３３０は、例えばＳＯＩ（Silicon On Insulator）基板である。この場合、導電層３３０は、不純物が導入されたシリコン層である。次いで、基板３１０の下面及び導電層３３０の上面を洗浄する。 First, as shown in FIG. 4A, a substrate having an insulating layer 320 and a conductive layer 330 formed on a substrate 310 is prepared. The substrate 310, the insulating layer 320, and the conductive layer 330 are, for example, SOI (Silicon On Insulator) substrates. In this case, the conductive layer 330 is a silicon layer into which impurities are introduced. Next, the lower surface of the substrate 310 and the upper surface of the conductive layer 330 are cleaned.

次いで図４（ｂ）に示すように、導電層３３０上にレジストパターン５０を形成する。次いで、レジストパターン５０をマスクとして導電層３３０をドライエッチングする。これにより、枠体１１０、可動電極１２０、保持部材１３０、固定電極１４０、及び第１検出用電極１５０が形成される。 Next, as shown in FIG. 4B, a resist pattern 50 is formed on the conductive layer 330. Next, the conductive layer 330 is dry etched using the resist pattern 50 as a mask. Thereby, the frame 110, the movable electrode 120, the holding member 130, the fixed electrode 140, and the first detection electrode 150 are formed.

その後、図５に示すように、レジストパターン５０を除去する。次いで、基板３１０の上にレジストパターン（図示せず）を形成し、このレジストパターンをマスクとして、基板３１０及び絶縁層３２０をエッチングする。これにより、基板３１０及び絶縁層３２０のうち可動電極１２０及び保持部材１３０の下に位置している部分は除去される。その後、レジストパターンは除去される。 Thereafter, as shown in FIG. 5, the resist pattern 50 is removed. Next, a resist pattern (not shown) is formed on the substrate 310, and the substrate 310 and the insulating layer 320 are etched using the resist pattern as a mask. As a result, portions of the substrate 310 and the insulating layer 320 located under the movable electrode 120 and the holding member 130 are removed. Thereafter, the resist pattern is removed.

また、絶縁板４００を準備し、絶縁板４００上に導電膜（例えば銅膜又はアルミニウム膜）を形成する。次いで、この導電膜を選択的に除去する。これにより、絶縁板４００上には第２検出用電極４１０及び配線が形成される。次いで、絶縁板４００を基板３１０に接合する。このようにして、図１及び図２に示した回転型アクチュエータ１００が形成される。 In addition, the insulating plate 400 is prepared, and a conductive film (eg, a copper film or an aluminum film) is formed over the insulating plate 400. Next, this conductive film is selectively removed. As a result, the second detection electrode 410 and the wiring are formed on the insulating plate 400. Next, the insulating plate 400 is bonded to the substrate 310. In this way, the rotary actuator 100 shown in FIGS. 1 and 2 is formed.

図６は、可動電極１２０の回転角度θと、可動電極１２０と第１検出用電極１５０の間に生じる静電容量との関係を示す図である。可動電極１２０の回転角度が０°、すなわち保持部材１３０がねじれていない場合、可動電極１２０と第１検出用電極１５０の間の静電容量は最大になる。そして、可動電極１２０が回転するにつれて、この静電容量は小さくなる。 FIG. 6 is a diagram showing the relationship between the rotation angle θ of the movable electrode 120 and the capacitance generated between the movable electrode 120 and the first detection electrode 150. When the rotation angle of the movable electrode 120 is 0 °, that is, when the holding member 130 is not twisted, the electrostatic capacitance between the movable electrode 120 and the first detection electrode 150 is maximized. Then, as the movable electrode 120 rotates, this capacitance decreases.

また、可動電極１２０と第１検出用電極１５０の厚さは等しく、また可動電極１２０の上面は第１検出用電極１５０の上面と同じ高さに位置している。このため、可動電極１２０が回転したとき、可動電極１２０と第１検出用電極１５０の間の静電容量は大きく変化する。ただし、可動電極１２０と第１検出用電極１５０の静電容量の変化量は、回転角度のみによって変化し、回転方向によっては変化しない。 The movable electrode 120 and the first detection electrode 150 are equal in thickness, and the upper surface of the movable electrode 120 is located at the same height as the upper surface of the first detection electrode 150. For this reason, when the movable electrode 120 rotates, the electrostatic capacitance between the movable electrode 120 and the first detection electrode 150 changes greatly. However, the amount of change in capacitance between the movable electrode 120 and the first detection electrode 150 changes only with the rotation angle, and does not change with the rotation direction.

このため、制御部２００は、図６に示したデータを予め記憶しておくことにより、第１検出用電極１５０と可動電極１２０の間に生じる静電容量の変化に基づいて、可動電極１２０の回転角度を高い精度で検出できる。ただし、制御部２００は、この静電容量からは可動電極１２０の回転方向を検出できない。 For this reason, the control unit 200 stores the data shown in FIG. 6 in advance, and based on the change in the capacitance generated between the first detection electrode 150 and the movable electrode 120, the control unit 200 stores the data shown in FIG. The rotation angle can be detected with high accuracy. However, the control unit 200 cannot detect the rotation direction of the movable electrode 120 from this capacitance.

図７は、可動電極１２０の回転角度θと、可動電極１２０と第２検出用電極４１０の間に生じる静電容量との関係を示す図である。可動電極１２０と第２検出用電極４１０は平面視において重なっている。このため可動電極１２０が第２検出用電極４１０に近づく方向（図８の例では−方向）に回転すると、可動電極１２０と第２検出用電極４１０の間の静電容量は大きくなる。また、可動電極１２０が第２検出用電極４１０から離れる方向（図８の例では＋方向）に回転すると、可動電極１２０と第２検出用電極４１０の間の静電容量は小さくなる。 FIG. 7 is a diagram illustrating the relationship between the rotation angle θ of the movable electrode 120 and the capacitance generated between the movable electrode 120 and the second detection electrode 410. The movable electrode 120 and the second detection electrode 410 overlap in plan view. For this reason, when the movable electrode 120 rotates in the direction approaching the second detection electrode 410 (the negative direction in the example of FIG. 8), the capacitance between the movable electrode 120 and the second detection electrode 410 increases. Further, when the movable electrode 120 rotates in a direction away from the second detection electrode 410 (in the + direction in the example of FIG. 8), the capacitance between the movable electrode 120 and the second detection electrode 410 decreases.

このため、制御部２００は、図７に示したデータ（特に可動電極１２０の回転角度が０°のときの静電容量）を予め記憶しておくことにより、可動電極１２０の回転方向を高い精度で検出できる。なお、制御部２００は、図７に示したデータから可動電極１２０の回転角度を検出することもできる。ただし、可動電極１２０と第２検出用電極４１０の間の静電容量は、可動電極１２０と第１検出用電極１５０の間の静電容量よりも小さい。このため、第１検出用電極１５０を用いたほうが、可動電極１２０の回転角度の検出精度は高くなる。 For this reason, the control unit 200 stores in advance the data shown in FIG. 7 (particularly, the capacitance when the rotation angle of the movable electrode 120 is 0 °), so that the rotation direction of the movable electrode 120 is highly accurate. Can be detected. Note that the control unit 200 can also detect the rotation angle of the movable electrode 120 from the data shown in FIG. However, the capacitance between the movable electrode 120 and the second detection electrode 410 is smaller than the capacitance between the movable electrode 120 and the first detection electrode 150. For this reason, the detection accuracy of the rotation angle of the movable electrode 120 is higher when the first detection electrode 150 is used.

図８は、可動電極１２０を１ｋＨｚで±５°の範囲で振動させたときの、可動電極１２０と第１検出用電極１５０の間の静電容量の変化を示している。このグラフからも、可動電極１２０と第１検出用電極１５０の間の静電容量を用いると、可動電極１２０の回転角度を判断できることが分かる。ただし、回転角度＝０°を原点とした場合、可動電極１２０と第１検出用電極１５０の間の静電容量の変化は、可動電極１２０が＋方向に回転した場合と−方向に回転した場合とで同一の値を示す。このため、制御部２００は、この静電容量からは可動電極１２０の回転方向を検出できない。 FIG. 8 shows a change in electrostatic capacitance between the movable electrode 120 and the first detection electrode 150 when the movable electrode 120 is vibrated in a range of ± 5 ° at 1 kHz. This graph also shows that the rotation angle of the movable electrode 120 can be determined by using the capacitance between the movable electrode 120 and the first detection electrode 150. However, when the rotation angle = 0 ° is the origin, the change in the capacitance between the movable electrode 120 and the first detection electrode 150 changes when the movable electrode 120 rotates in the + direction and in the − direction. And show the same value. For this reason, the control unit 200 cannot detect the rotation direction of the movable electrode 120 from the capacitance.

図９は、可動電極１２０を１ｋＨｚで±５°の範囲で振動させたときの、可動電極１２０と第２検出用電極４１０の間の静電容量の変化を示している。このグラフからも、可動電極１２０と第２検出用電極４１０の間の静電容量を用いると、可動電極１２０の回転方向を判断できることが分かる。 FIG. 9 shows a change in capacitance between the movable electrode 120 and the second detection electrode 410 when the movable electrode 120 is vibrated in the range of ± 5 ° at 1 kHz. From this graph, it can be seen that the rotational direction of the movable electrode 120 can be determined by using the capacitance between the movable electrode 120 and the second detection electrode 410.

以上、本実施形態によれば、回転型アクチュエータ１００は、第１検出用電極１５０及び第２検出用電極４１０を備えている。そして、可動電極１２０の回転角度は、可動電極１２０と第１検出用電極１５０の間の静電容量に基づいて、精度良く判断される。また可動電極１２０の回転方向は、可動電極１２０と第２検出用電極４１０の間の静電容量に基づいて、精度良く判断される。 As described above, according to the present embodiment, the rotary actuator 100 includes the first detection electrode 150 and the second detection electrode 410. The rotation angle of the movable electrode 120 is accurately determined based on the capacitance between the movable electrode 120 and the first detection electrode 150. The rotation direction of the movable electrode 120 is accurately determined based on the capacitance between the movable electrode 120 and the second detection electrode 410.

以上、図面を参照して本発明の実施形態について述べたが、これらは本発明の例示であり、上記以外の様々な構成を採用することもできる。 As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.

５０レジストパターン
１００回転型アクチュエータ
１１０枠体
１２０可動電極
１３０保持部材
１４０固定電極
１５０第１検出用電極
２００制御部
３１０基板
３２０絶縁層
３３０導電層
４００絶縁板
４１０第２検出用電極 50 resist pattern 100 rotary actuator 110 frame 120 movable electrode 130 holding member 140 fixed electrode 150 first detection electrode 200 control unit 310 substrate 320 insulating layer 330 conductive layer 400 insulating plate 410 second detection electrode

Claims

A movable electrode;
A frame,
The movable electrode is attached to the frame, and a holding member that serves as a rotation axis of the movable electrode
A fixed electrode facing the movable electrode in plan view;
A first detection electrode that is insulated from the movable electrode and the fixed electrode and faces one side of the movable electrode in plan view;
A second detection electrode that is insulated from the movable electrode and the fixed electrode, and at least partially overlaps the movable electrode in plan view;
A rotary actuator comprising:

The rotary actuator according to claim 1, wherein
A first support member overlapping the movable electrode in plan view;
A second support member for fixing the first support member to the fixed electrode in a state of being separated from the movable electrode;
With
The second detection electrode is a rotary actuator provided on the first support member.

The rotary actuator according to claim 1 or 2,
The rotary actuator in which the second detection electrode does not overlap the holding member in plan view.

The rotary actuator according to any one of claims 1 to 3,
A control unit for controlling a voltage applied between the movable electrode and the fixed electrode;
The controller is
Determining a rotation angle of the movable electrode based on a first capacitance between the first detection electrode and the movable electrode;
A rotary actuator that determines a rotation direction of the movable electrode based on a second capacitance between the second detection electrode and the movable electrode.