Actuator

Abstract

To appropriately detect a state of at least one of two opposed members while appropriately controlling the state of at least one of the two members.MEANS: An actuator (1) comprises a first member (11), and a second member (12) opposed to the first member. A first control electrode (113) and a first detection electrode (114) are formed on a first opposed surface (111) opposed to the second member, of the first member. A second control electrode (123) and a second detection electrode (124) are formed on a second opposed surface (121) opposed to the first member, of the second member. The first control electrode and the first detection electrode, and / or the second control electrode and the second detection electrode, are electrically isolated from each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an actuator that can control (eg, move) the state of at least one of two opposing members. [Background technology]

[0002] An example of a product that employs such an actuator is the optical filter disclosed in Patent Document 1. The optical filter disclosed in Patent Document 1 includes a first substrate, a second substrate facing the first substrate, a first reflective film provided on a first opposing surface where the first substrate faces the second substrate, a second reflective film provided on a second opposing surface where the second substrate faces the first substrate, a first electrode provided on the first opposing surface, and a second electrode provided on the second opposing surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-191554 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0004] The first and second electrodes disclosed in Patent Document 1 are used to control (i.e., change) the gap between the first and second substrates by controlling (e.g., moving) the state of the first substrate. Here, in order to control the gap with precision, it is preferable to detect the actual state of the gap (in other words, the state of the first substrate) and control the gap based on the detection results. However, the optical filter disclosed in Patent Document 1 only includes the first and second electrodes used to control the gap, which presents a technical problem in that it is not possible to detect the actual state of the gap.

[0005] On the other hand, it is also conceivable that the optical filter disclosed in Patent Document 1 can detect the actual state of the gap using the first and second electrodes used to control the gap. However, the signal for controlling the gap and the signal for detecting the gap state flow together through the same electrodes (i.e., the first and second electrodes). This results in a technical problem in that the configuration of the signal processing circuit for controlling the gap and detecting the gap state becomes complicated.

[0006] The above-mentioned technical problem is not limited to the optical filter, but may similarly occur in any structure (for example, an actuator) that controls the states of two opposing members.

[0007] The above is an example of the problem that the present invention aims to solve. An object of the present invention is to provide an actuator that can relatively easily control the state of at least one of two opposing members while detecting the state of at least one of the two members. [Means for solving the problem]

[0008] An actuator that solves the above problem comprises a first member and a second member facing the first member, wherein a first control electrode and a first detection electrode are formed on a first opposing surface of the first member facing the second member, and a second control electrode facing the first control electrode and a second detection electrode facing the first detection electrode are formed on a second opposing surface of the second member facing the first member, and the first control electrode and the first detection electrode and / or the second control electrode and the second detection electrode are electrically isolated from each other.

[0009] Such functions and advantages of the present invention will become apparent from the following embodiments. [Brief explanation of the drawings]

[0010] [Figure 1]2A and 2B are a top view and a cross-sectional view taken along line II' of the actuator of the first embodiment. [Figure 2] 10 is a graph showing the relationship between the distance between the first sensor electrode and the second sensor electrode and the capacitance of the first sensor electrode and the second sensor electrode. [Figure 3] 3A and 3B are a top view and a cross-sectional view taken along line III-III' of an actuator according to a second embodiment of the present invention; [Figure 4] 4A and 4B are a top view and a cross-sectional view taken along line IV-IV' of an actuator according to a third embodiment of the present invention; [Figure 5] 10A and 10B are a top view and a VV′ cross-sectional view of an actuator according to a fourth embodiment of the present invention; [Figure 6] 6A and 6B are a top view and a cross-sectional view taken along the line VI-VI' of an actuator according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the actuator of the present invention will be described in order.

[0012] <1> The actuator of this embodiment includes a first member and a second member facing the first member, and a first opposing surface of the first member facing the second member is formed with (i) a first control electrode and (ii) a first detection electrode different from the first control electrode, and a second opposing surface of the second member facing the first member is formed with (i) a second control electrode facing the first control electrode and (ii) a second detection electrode facing the first detection electrode, The first control electrode and the first detection electrode and / or the second control electrode and the second detection electrode are electrically isolated.

[0013] According to the actuator of this embodiment, a first member and a second member face each other. The first member includes a first opposing surface facing the second member (in other words, facing the second opposing surface). Two types of electrodes (i.e., first control electrodes and first detection electrodes) are formed on the first opposing surface. The second member includes a second opposing surface facing the first member (in other words, facing the first opposing surface). Two types of electrodes (i.e., second control electrodes and second detection electrodes) are formed on the second opposing surface.

[0014] Particularly in this embodiment, the first control electrode and the first detection electrode and / or the second control electrode and the second detection electrode are electrically separated. For example, in a first aspect of the actuator, the first control electrode and the first detection electrode are electrically separated, and the second control electrode and the second detection electrode are electrically separated. For example, in a second aspect of the actuator, the first control electrode and the first detection electrode are electrically separated, while the second control electrode and the second detection electrode may not be electrically separated. For example, in a third aspect of the actuator, the second control electrode and the second detection electrode are electrically separated, while the first control electrode and the first detection electrode may not be electrically separated.

[0015] The state in which "A and B are electrically separated" means that there is no electrical continuity between A and B (i.e., they are not electrically connected). In other words, the state in which "A and B are electrically separated" means that A and B are electrically independent.

[0016] As described above, according to the actuator of this embodiment, two types of pairs of electrodes are formed on each of the first member and the second member. Therefore, the actuator can use one type of pair of electrodes (e.g., first and second control electrodes) of these two types of pairs of electrodes for a first purpose. On the other hand, the actuator can use the other type of pair of electrodes (e.g., first and second detection electrodes) of these two types of pairs of electrodes for a second purpose that is different from the first purpose. Therefore, the actuator of this embodiment can perform an operation for the second purpose while performing an operation for the first purpose.

[0017] Specifically, for example, the actuator can use one type of pair of electrodes (e.g., first and second control electrodes) of these two types of pairs of electrodes to control the state of at least one of the first and second members. On the other hand, the actuator can use the other type of pair of electrodes (e.g., first and second detection electrodes) of these two types of pairs of electrodes to detect the state of at least one of the first and second members. Therefore, the actuator can control the state of at least one of the first and second members while detecting the actual state of at least one of the first and second members. Therefore, compared to an actuator that does not have two types of pairs of electrodes, the actuator of this embodiment can accurately control the state of at least one of the first and second members.

[0018] Additionally, in the actuator of this embodiment, the first control electrode and the first detection electrode and / or the second control electrode and the second detection electrode are electrically separated. Therefore, the actuator can handle two types of signals, one flowing through the first and second control electrodes for the first application and the other flowing through the first and second detection electrodes for the second application, while these two types of signals are electrically separated. Therefore, compared to an actuator in which the first control electrode and the first detection electrode are not electrically separated and the second control electrode and the second detection electrode are not electrically separated, the actuator of this embodiment has a simpler configuration for a signal processing circuit that performs signal processing for the first application and signal processing for the second application.

[0019] Specifically, for example, the actuator can handle two types of signals, one of which flows through the first and second control electrodes for controlling the state of at least one of the first and second members and the other of which flows through the first and second detection electrodes for detecting the state of at least one of the first and second members, while these two types of signals are electrically separated. Therefore, compared to an actuator in which the first control electrode and the first detection electrode are not electrically separated and the second control electrode and the second detection electrode are not electrically separated, the actuator of this embodiment has a simplified configuration of a signal processing circuit for controlling the state of at least one of the first and second members and detecting the state of at least one of the first and second members.

[0020] In this way, the actuator of this embodiment can relatively easily perform an operation for a first purpose on at least one of two opposing members (i.e., first and second members) while performing an operation for a second purpose on at least one of the two members. Specifically, for example, the actuator of this embodiment can relatively easily detect the state of at least one of the two opposing members (i.e., first and second members) while controlling the state of at least one of the two members.

[0021] <2> In another aspect of the actuator of this embodiment, the first and second control electrodes are electrodes for controlling the state of at least one of the first and second members, and the first and second detection electrodes are electrodes for detecting the state of at least one of the first and second members.

[0022] According to this aspect, the actuator can relatively easily detect the state of at least one of the two opposing members (i.e., the first and second members) while controlling the state of at least one of the two members.

[0023] <3> In another aspect of the actuator of the present embodiment, an initial distance between the first detection electrode and the second detection electrode is smaller than an initial distance between the first control electrode and the second control electrode.

[0024] According to this aspect, it is possible to suitably perform an operation for a first application using the first and second control electrodes and an operation for a second application using the first and second detection electrodes while appropriately satisfying the respective requirements. Note that the "initial distance" refers to the distance when the first and second members are in their initial states (e.g., when the first and second members are not controlled).

[0025] As a specific example, consider an actuator in which the first and second control electrodes are electrodes for controlling the state of at least one of the first and second members, and the first and second detection electrodes are electrodes for detecting the state of at least one of the first and second members.

[0026] In such an actuator, signals for controlling the state of at least one of the first and second members are typically supplied to the first and second control electrodes. As a result, the state of at least one of the first and second members is controlled by electrostatic forces generated in the first and second control electrodes. In this case, when the distance between the first and second control electrodes becomes smaller than the initial distance between the first and second control electrodes by a predetermined percentage or more (e.g., becomes 2 / 3), a pull-in state occurs in which the first and second control electrodes come into contact with each other. When the pull-in state occurs, it becomes difficult to control the state of at least one of the first and second members. Therefore, in order to relatively increase the control amount of the state of at least one of the first and second members, it is preferable that the initial distance between the first and second control electrodes is relatively large.

[0027] On the other hand, in such an actuator, the capacitance of the first and second detection electrodes is detected to detect the state of at least one of the first and second members. This is because the capacitance of the first and second detection electrodes changes depending on the distance between the first and second detection electrodes. Therefore, the distance between the first and second detection electrodes can be detected based on the capacitance of the first and second detection electrodes. As a result, the state of at least one of the first and second members is detected from the distance between the first and second detection electrodes. Here, the detection accuracy of the state of at least one of the first and second members substantially depends on the detection accuracy of the distance between the first and second detection electrodes. The detection accuracy of the distance between the first and second detection electrodes improves as the amount of change in the capacitance of the first and second detection electrodes increases with a given change in the distance between the first and second detection electrodes. Therefore, considering that the capacitance of the first and second detection electrodes is inversely proportional to the distance between the first and second detection electrodes, the amount of change in the capacitance of the first and second detection electrodes with a given change in the distance between the first and second detection electrodes increases as the initial distance between the first and second detection electrodes becomes smaller. Therefore, in order to improve the detection accuracy of the distance between the first and second detection electrodes (in other words, the detection accuracy of the state of at least one of the first and second members), it is preferable that the initial distance between the first and second detection electrodes is relatively small.

[0028] As described above, there may be a conflicting requirement that the initial distance between one type of electrode (e.g., the first and second control electrodes) of two pairs of electrodes is preferably relatively large, while the initial distance between the other type of electrode (e.g., the first and second detection electrodes) of the two pairs of electrodes is preferably relatively small. Therefore, in the actuator of this aspect, in order to meet these conflicting requirements, the initial distance between the first detection electrode and the second detection electrode is smaller than the initial distance between the first control electrode and the second control electrode. Therefore, the actuator of this aspect can, for example, preferably control the state of at least one of two opposing members (i.e., the first and second members) while preferably detecting the state of at least one of the two members.

[0029] <4> In another aspect of the actuator of this embodiment, one of the first detection electrodes and another of the first detection electrodes are formed on the first opposing surface, one of the second detection electrodes opposing the one of the first detection electrodes and another of the second detection electrodes opposing the another of the first detection electrodes are formed on the second opposing surface, and the initial distance between the one of the first detection electrodes and the one of the second detection electrodes is different from the initial distance between the another of the first detection electrodes and the another of the second detection electrodes.

[0030] According to this aspect, the actuator includes a plurality of combinations of first and second detection electrodes. In particular, the initial intervals between the first and second detection electrodes in each of the plurality of combinations are different from one another. Therefore, the actuator can appropriately change the combination of first and second detection electrodes used to perform an operation for the second purpose as needed.

[0031] As a specific example, for example, an actuator is assumed in which the first and second detection electrodes are electrodes for detecting the state of at least one of the first and second members.

[0032] In such an actuator, as described above, the capacitances of the first and second detection electrodes are detected to detect the state of at least one of the first and second members. Furthermore, as described above, a relatively small initial distance between the first and second detection electrodes is preferable to improve the detection accuracy of the state of at least one of the first and second members. However, if the initial distance between the first and second detection electrodes is relatively small, the first and second detection electrodes are likely to come into contact with each other depending on the control amount of the state of at least one of the first and second members. In this case, a technical problem arises in that it becomes difficult to detect the state of at least one of the first and second members using the contacting first and second detection electrodes. Therefore, the actuator solves this technical problem by changing the combination of the first and second detection electrodes used to detect the state of at least one of the first and second members. For example, when the control amount of the state of at least one of the first and second members is a first amount, the actuator detects the state of at least one of the first and second members using the first and second detection electrodes with a relatively small initial distance. On the other hand, when the possibility of one of the first and second detection electrodes coming into contact with each other becomes relatively high due to a change in the control amount of the state of at least one of the first and second members to a second amount different from the first amount, the actuator detects the state of at least one of the first and second members using the first and second detection electrodes having a relatively large initial interval instead of the first and second detection electrodes having a relatively small initial interval, so that the actuator can detect the state of at least one of the first and second members regardless of the control amount of the state of at least one of the first and second members.

[0033] <5> In another aspect of the actuator in which one first and second detection electrodes and other first and second detection electrodes are formed as described above, the first and second detection electrodes are electrodes for detecting the state of at least one of the first and second members, and switching is performed between a first detection mode in which the state is detected using the one first detection electrode and the one second detection electrode, and a second detection mode in which the state is detected using the other first detection electrode and the other second detection electrode.

[0034] According to this aspect, as described above, the actuator can change the combination of the first and second detection electrodes used to detect the state of at least one of the first and second members, and as a result, the actuator can detect the state of at least one of the first and second members regardless of the control amount of the state of at least one of the first and second members.

[0035] <6> In another aspect of the actuator of the present embodiment, the first detection electrode and the second detection electrode are semi-transparent films.

[0036] According to this aspect, the actuator can be used as a Fabry-Perot type spectroscopic element.

[0037] <7> In another aspect of the actuator of this embodiment, the first detection electrode is divided into a plurality of first electrode portions distributed on a virtual plane intersecting the direction in which the first member and the second member face each other, and the second detection electrode is divided into a plurality of second electrode portions distributed on a virtual plane intersecting the direction in which the first member and the second member face each other.

[0038] According to this aspect, compared to when the first and second detection electrodes are not divided, the operation for the second application using the first and second detection electrodes can be performed in a new manner using the multiple first and second electrode portions obtained by dividing the first and second detection electrodes, respectively.

[0039] As a specific example, for example, an actuator is assumed in which the first and second detection electrodes are electrodes for detecting the state of at least one of the first and second members.

[0040] In such an actuator, as described above, the capacitances of the first and second detection electrodes are detected to detect the state of at least one of the first and second members. Because the first and second detection electrodes are each divided into a plurality of first and second electrode portions, the capacitance of each combination of opposing first and second electrode portions is detected. For example, the capacitance of a combination of one opposing first electrode portion and one opposing second electrode portion, and the capacitance of another opposing first electrode portion and another opposing second electrode portion are detected. As a result, the distance between each combination of opposing first and second electrode portions is detected. Considering that the plurality of first electrode portions and the plurality of second electrode portions are distributed on a virtual plane intersecting the direction in which the first and second members face each other, the actuator can detect the tilt (i.e., inclination) of at least one of the first and second members by detecting the capacitance (i.e., the distance) between each combination of opposing first and second electrode portions. Therefore, the actuator can operate to correct the detected tilt.

[0041] These effects and other advantages of this embodiment will become more apparent from the examples described below.

[0042] As described above, the actuator of this embodiment includes first and second control electrodes and first and second detection electrodes, and the first control electrode and the first detection electrode and / or the second control electrode and the second detection electrode are electrically isolated from each other. Therefore, it is relatively easy to control the state of at least one of two opposing members while detecting the state of at least one of the two members. [Example]

[0043] Hereinafter, an embodiment of the actuator of the present invention will be described with reference to the drawings.

[0044] (1) First Example First, an actuator 1 according to a first embodiment will be described with reference to FIGS. 1(a) to 1(c). FIG. 1(a) is a top view of the actuator 1 according to the first embodiment. FIG. 1(b) is a cross-sectional view taken along line I-I' of the actuator 1 according to the first embodiment shown in FIG. 1(a) (however, no drive signal is supplied to the first actuator electrode 113 and the second actuator electrode 123). FIG. 1(c) is a cross-sectional view taken along line I-I' of the actuator 1 according to the first embodiment shown in FIG. 1(a) (however, drive signals are supplied to the first actuator electrode 113 and the second actuator electrode 123). Note that FIGS. 1(a) to 1(c) will be described using an example in which the actuator 1 is arranged in a virtual three-dimensional space defined by mutually orthogonal X-, Y-, and Z-axes.

[0045] As shown in FIGS. 1(a) and 1(b), the actuator 1 includes a first substrate 11, which is a specific example of a "first member," and a second substrate 12, which is a specific example of a "second member."

[0046] The first substrate 11 is a flat or plate-like member along the XY plane. The first substrate 11 has a rectangular shape on the XY plane. The second substrate 12 is also a flat or plate-like member along the XY plane. The second substrate 11 has a rectangular shape on the XY plane. The first substrate 11 and the second substrate 12 may be, for example, glass substrates, silicon substrates, or substrates made of other materials.

[0047] In the first substrate 11, the thickness (i.e., the length along the Z-axis direction) of a portion 112 of the first substrate 11 is smaller than the thickness of other portions of the first substrate 11. In the example shown in Fig. 1(a), the portion 112 having the relatively smaller thickness has a ring-like shape on the XY plane. In other words, the first substrate 11 has a membrane structure.

[0048] The first substrate 11 and the second substrate 12 are supported by a support member 13 extending along the Z-axis direction. The support member 13 supports the first substrate 11 and the second substrate 12 so that in the initial state, the distance along the Z-axis direction between the first substrate 11 and the second substrate 12 is "d1" (hereinafter, the distance along the Z-axis direction will be simply referred to as "distance").

[0049] The "initial state" refers to a state in which the first substrate 11 is not distorted. In other words, the "initial state" refers to a state in which no drive signals are supplied to the first actuator electrodes 113 and the second actuator electrodes 123, which will be described later.

[0050] The first substrate 11 has a first opposing surface 111. The first opposing surface 111 is a surface of the first substrate 11 that is parallel to the XY plane and faces the second substrate 12 (in other words, faces the −Z axis direction or faces the second opposing surface 121).

[0051] The second substrate 12 has a second opposing surface 121. The second opposing surface 121 is a surface of the second substrate 12 that is parallel to the XY plane and faces the first substrate 11 (in other words, faces the +Z axis direction or faces the first opposing surface 111). The second opposing surface 121 is a surface that is parallel to the first opposing surface 111.

[0052] The second opposing surface 121 includes a first surface 121a and a second surface 121b that is surrounded by the first surface 121a and protrudes toward the first substrate 11 side (in other words, toward the +Z-axis direction) compared to the first surface 121a. In other words, a step is essentially formed in the second opposing surface 121.

[0053] In the first embodiment, the distance between the first substrate 11 and the second substrate 12 is the distance between the first opposing surface 111 and the second surface 121b. However, the distance between the first substrate 11 and the second substrate 12 may be the distance between the first opposing surface 111 and the first surface 121a.

[0054] A first actuator electrode 113, which is a specific example of a "first control electrode," and a first sensor electrode 114, which is a specific example of a "first detection electrode," are formed on the first opposing surface 111. A second actuator electrode 123, which is a specific example of a "second control electrode," and a second sensor electrode 124, which is a specific example of a "second detection electrode," are formed on the second opposing surface 121. Each of the first actuator electrode 113, the first sensor electrode 114, the second actuator electrode 123, and the second sensor electrode 124 is an electrode containing, for example, a metal.

[0055] 1(a), the first actuator electrode 113 and the first sensor electrode 114, and the second actuator electrode 123 and the second sensor electrode 124, each have a ring shape on the XY plane. Furthermore, the center of each of the first actuator electrode 113 and the first sensor electrode 114, and the second actuator electrode 123 and the second sensor electrode 124, coincides with the center of the portion 112 where the thickness is relatively small (i.e., the rolled portion that defines the membrane structure). For convenience, the shapes of the first actuator electrode 113 and the first sensor electrode 114, and the second actuator electrode 123 and the second sensor electrode 124 are shown by dotted lines in FIG. 1(a).

[0056] The first actuator electrode 113 faces the second actuator electrode 123. That is, the first actuator electrode 113 and the second actuator electrode 123 are aligned along the Z-axis direction. Furthermore, the first sensor electrode 114 faces the second sensor electrode 124. That is, the first sensor electrode 114 and the second sensor electrode 124 are aligned along the Z-axis direction.

[0057] The first actuator electrode 113 and the second actuator electrode 123 are electrodes for controlling the state of the first substrate 11. Specifically, the first actuator electrode 113 and the second actuator electrode 123 are electrodes for distorting or moving the first substrate 11.

[0058] More specifically, drive signals for controlling the state of the first substrate 11 are supplied from a drive signal processing circuit (not shown) to the first actuator electrode 113 and the second actuator electrode 123. When the drive signals are supplied to the first actuator electrode 113 and the second actuator electrode 123, an electrostatic force is generated between the first actuator electrode 113 and the second actuator electrode 123. As a result, the first actuator electrode 113 and the second actuator electrode 123 attract (or move away from) each other along the Z-axis direction. As a result, the first substrate 11, which has a membrane structure and is thus more likely to be distorted than the second substrate 12, is distorted as shown in Fig. 1(c). That is, in the first embodiment, while the second substrate 12 functions as a fixed substrate that is substantially fixed, the first substrate 11 functions as a movable substrate that can move substantially. As a result, the distance between the first substrate 11 and the second substrate 12 changes.

[0059] The first sensor electrode 114 and the second sensor electrode 124 are electrodes for detecting the state of the first substrate 11. Specifically, the first sensor electrode 114 and the second sensor electrode 124 are electrodes for detecting the distance between the first substrate 11 and the second substrate 12.

[0060] More specifically, when the distance between the first substrate 11 and the second substrate 12 changes, the distance between the first sensor electrode 114 and the second sensor electrode 124 also changes. For example, as shown in Figs. 1(b) and 1(c), when the first substrate 11 is distorted and the distance between the first substrate 11 and the second substrate 12 changes from "d1" to "d1' (where d1' < d1 in the example shown in Fig. 1(c)), the distance between the first sensor electrode 114 and the second sensor electrode 124 also changes from "d2" to "d2' (where d2' < d2 in the example shown in Fig. 1(c)). When the distance between the first sensor electrode 114 and the second sensor electrode 124 changes, the capacitance of the first sensor electrode 114 and the second sensor electrode 124 also changes. Therefore, a detection signal processing circuit (not shown) can substantially detect the distance between the first substrate 11 and the second substrate 12 by detecting the capacitance of the first sensor electrode 114 and the second sensor electrode 124 as a detection signal.

[0061] Particularly in the first embodiment, the second actuator electrode 123 is formed on the first surface 121a of the second opposing surface 121. On the other hand, the second sensor electrode 124 is formed on the second surface 121b of the second opposing surface 121. As a result, the distance d3 between the first sensor electrode 114 and the second sensor electrode 124 in the initial state is smaller than the distance d2 between the first actuator electrode 113 and the second actuator electrode 123 in the initial state.

[0062] Additionally, in the first embodiment, the first actuator electrode 113 and the first sensor electrode 114 are electrically isolated. In other words, the first actuator electrode 113 and the first sensor electrode 114 are electrically independent. In other words, the first actuator electrode 113 and the first sensor electrode 114 are not electrically connected.

[0063] Additionally, in the first embodiment, the second actuator electrode 123 and the second sensor electrode 124 are electrically isolated. In other words, the second actuator electrode 123 and the second sensor electrode 124 are electrically independent. In other words, the second actuator electrode 123 and the second sensor electrode 124 are not electrically connected.

[0064] According to the actuator 1 described above, two types of electrodes (i.e., the first actuator electrode 113 and the first sensor electrode 114) are formed on the first substrate 11. Two types of electrodes (i.e., the second actuator electrode 123 and the second sensor electrode 124) are also formed on the second substrate 12. Therefore, the actuator 1 can control the state of the first substrate 11 (i.e., distort the first substrate 11) using the first actuator electrode 113 and the second actuator electrode 123 of these two types of electrodes. On the other hand, the actuator 1 can detect the state of the first substrate 11 (i.e., detect the distance between the first substrate 11 and the second substrate 12) using the first sensor electrode 114 and the second sensor electrode 124 of these two types of electrodes. Therefore, the actuator 1 can distort the first substrate 11 (i.e., control the distance between the first substrate 11 and the second substrate 12) while detecting the distance between the first substrate 11 and the second substrate 12. For example, the actuator 1 can distort the first substrate 11 by a desired amount so that the distance between the first substrate 11 and the second substrate 12 becomes a desired distance. Therefore, the actuator 1 can distort the first substrate 11 with higher precision (i.e., control the distance between the first substrate 11 and the second substrate 12 with higher precision) compared to the actuator of the first comparative example in which the first sensor electrode 114 and the second sensor electrode 124 are not formed.

[0065] Additionally, in the actuator 1 of the first embodiment, the first actuator electrode 113 and the first sensor electrode 114 are electrically isolated, and the second actuator electrode 123 and the second sensor electrode 124 are electrically isolated. Therefore, the drive signal supplied to the first actuator electrode 113 and the second actuator electrode 123 to distort the first substrate 11 and the detection signal flowing through the first sensor electrode 114 and the second sensor electrode 124 to detect the gap between the first substrate 11 and the second substrate 12 are electrically isolated. In other words, the actuator 1 can handle these two types of signals with the drive signal and the detection signal electrically isolated. Therefore, compared to the actuator of the second comparative example in which the first actuator electrode 113 and the first sensor electrode 114 are not electrically separated and the second actuator electrode 123 and the second sensor electrode 124 are not electrically separated, the actuator 1 has a simplified circuit configuration for the drive signal processing circuit that performs signal processing to distort the first substrate 11 and the detection signal processing circuit that performs signal processing to detect the gap between the first substrate 11 and the second substrate 12.

[0066] In this way, the actuator 1 of the first embodiment can relatively easily detect the state of the first substrate 11 while controlling the state of the first substrate 11. In other words, the actuator 1 of the first embodiment can relatively easily detect the gap between the first substrate 11 and the second substrate 12 while distorting the first substrate 11.

[0067] Additionally, according to the actuator 1 of the first embodiment, the distance d3 between the first sensor electrode 114 and the second sensor electrode 124 in the initial state is smaller than the distance d2 between the first actuator electrode 113 and the second actuator electrode 123 in the initial state. Here, the technical effect achieved by making the distance d3 smaller than the distance d2 will be described with reference to Fig. 2. Fig. 2 is a graph showing the relationship between the distance between the first sensor electrode 114 and the second sensor electrode 124 and the capacitance of the first sensor electrode 114 and the second sensor electrode 124.

[0068] First, in the actuator 1 of the first embodiment, as described above, the first substrate 11 is distorted by the electrostatic force generated in the first actuator electrode 113 and the second actuator electrode 123. In this case, when the distance between the first actuator electrode 113 and the second actuator electrode 123 becomes smaller than the distance d1 in the initial state by a predetermined percentage or more (for example, becomes ⅔ of the distance d1), a pull-in state occurs in which the first actuator electrode 113 and the second actuator electrode 123 come into contact with each other. When the pull-in state occurs, it becomes difficult to distort the first substrate 11 by the electrostatic force generated in the first actuator electrode 113 and the second actuator electrode 123. Therefore, in order to widen the movable range of the first substrate 11 by relatively increasing the amount of distortion of the first substrate 11, it is preferable that the distance d2 between the first actuator electrode 113 and the second actuator electrode 123 in the initial state be relatively large.

[0069] On the other hand, in the actuator 1 of the first embodiment, the distance between the first substrate 11 and the second substrate 12 is detected based on the capacitance of the first sensor electrode 114 and the second sensor electrode 124. Therefore, the accuracy of detecting the distance between the first substrate 11 and the second substrate 12 improves as the amount of change in the capacitance of the first sensor electrode 114 and the second sensor electrode 124 increases with respect to a predetermined change in the distance between the first substrate 11 and the second substrate 12. However, considering that the distance between the first substrate 11 and the second substrate 12 is substantially equivalent to the distance between the first sensor electrode 114 and the second sensor electrode 124, the accuracy of detecting the distance between the first substrate 11 and the second substrate 12 improves as the amount of change in the capacitance of the first sensor electrode 114 and the second sensor electrode 124 increases with respect to a predetermined change in the distance between the first sensor electrode 114 and the second sensor electrode 124. Here, the capacitance of the first sensor electrode 114 and the second sensor electrode 124 is derived from the mathematical formula: dielectric constant of the medium between the first sensor electrode 114 and the second sensor electrode 124 × (surface area of the first sensor electrode 114 or the second sensor electrode 124 / distance between the first sensor electrode 114 and the second sensor electrode 124). That is, as shown in FIG. 2, the capacitance of the first sensor electrode 114 and the second sensor electrode 124 is inversely proportional to the distance between the first sensor electrode 114 and the second sensor electrode 124. Then, as can be seen from the graph shown in FIG. 2, the smaller the distance d3 between the first sensor electrode 114 and the second sensor electrode 124 in the initial state, the larger the change in the capacitance of the first sensor electrode 114 and the second sensor electrode 124 with respect to a given change in the distance between the first sensor electrode 114 and the second sensor electrode 124. For example, as shown in FIG. 2, when the distance between the first sensor electrode 114 and the second sensor electrode 124 in the initial state is "d3a," the amount of change in capacitance of the first sensor electrode 114 and the second sensor electrode 124 with respect to a change in the distance between the first sensor electrode 114 and the second sensor electrode 124 by a predetermined amount ±Δd is "Va."On the other hand, when the distance between the first sensor electrode 114 and the second sensor electrode 124 in the initial state is "d3b (where d3b > d3a)", the change amount of the capacitance of the first sensor electrode 114 and the second sensor electrode 124 with respect to a change of a predetermined amount ±Δd in the distance between the first sensor electrode 114 and the second sensor electrode 124 is "Vb (where Vb < Va)". That is, the detection accuracy of the capacitance when the distance between the first sensor electrode 114 and the second sensor electrode 124 in the initial state is relatively small "d3a" is better than the detection accuracy when the distance between the first sensor electrode 114 and the second sensor electrode 124 in the initial state is relatively large "d3b". In other words, the detection accuracy of the distance between the first substrate 11 and the second substrate 12 when the distance between the first sensor electrode 114 and the second sensor electrode 124 in the initial state is relatively small "d3a" is better than the distance between the first substrate 11 and the second substrate 12 when the distance between the first sensor electrode 114 and the second sensor electrode 124 in the initial state is relatively large "d3b". Therefore, in order to improve the detection accuracy of the distance between the first substrate 11 and the second substrate 12, it is preferable that the distance d3 between the first sensor electrode 114 and the second sensor electrode 124 in the initial state is relatively small.

[0070] As described above, it is desirable that the distance d2 between the first actuator electrode 113 and the second actuator electrode 123 in the initial state be relatively large, while it is desirable that the distance d3 between the first sensor electrode 114 and the second sensor electrode 124 in the initial state be relatively small. In other words, it is desirable that the distances d1 and d3 satisfy mutually contradictory requirements. In consideration of the fact that the distances d2 and d3 satisfy such contradictory requirements, in the actuator 1 of the first embodiment, the distance d3 between the first sensor electrode 114 and the second sensor electrode 124 in the initial state is smaller than the distance d2 between the first actuator electrode 113 and the second actuator electrode 123 in the initial state. As a result, the actuator 1 can relatively increase the distance d2 between the first actuator electrode 113 and the second actuator electrode 123 in the initial state, thereby relatively increasing the amount of distortion of the first substrate 11 and thereby widening the movable range of the first substrate 11. On the other hand, the actuator 1 can make the distance d3 between the first sensor electrode 114 and the second sensor electrode 124 relatively small in the initial state, thereby improving the detection accuracy of the distance between the first substrate 11 and the second substrate 12.

[0071] It should be noted that the actuator 1 shown in Figures 1(a) to 1(c) is merely an example. Therefore, the present invention is not limited to the actuator 1 shown in Figures 1(a) to 1(c). Some modified examples of the actuator 1 are listed below.

[0072] The first substrate 11 does not have to be a flat or plate-like member. The shape of the first substrate 11 on the XY plane does not have to be rectangular. The second substrate 12 does not have to be a flat or plate-like member. The shape of the second substrate 12 on the XY plane does not have to be rectangular.

[0073] The shape of the portion 112 where the thickness is relatively small on the XY plane does not have to be ring-shaped. The first substrate 11 does not have to have the portion 112 where the thickness is relatively small. The first substrate 11 does not have to have a membrane structure.

[0074] The support member 13 may be a member separate from both the first substrate 11 and the second substrate 12. The support member 13 may be a member integrated with at least one of the first substrate 11 and the second substrate 12.

[0075] At least one of the first opposing surface 111 and the second opposing surface 121 may be a surface that is not parallel to the XY plane (i.e., a surface that is inclined with respect to the XY plane). At least one of the first opposing surface 111 and the second opposing surface 121 may include a surface that is not parallel to the XY plane. At least one of the first opposing surface 111 and the second opposing surface 121 may include a curved surface. The second opposing surface 121 may include a surface that is not parallel to the first opposing surface 111 (i.e., a surface that is inclined with respect to the first opposing surface 111).

[0076] In addition to or instead of the second opposing surface 121 including the first surface 121a and the second surface 121b, the first opposing surface 111 may include a first surface and a second surface that is surrounded by the first surface and protrudes toward the second substrate 12 side (in other words, the -Z axis direction side) compared to the first surface. That is, in addition to or instead of forming a step on the second opposing surface 121, a step may be formed on the first opposing surface 111. In this case, the first actuator electrode 113 may be formed on the first surface of the first opposing surface 111. On the other hand, the first sensor electrode 114 may be formed on the second surface of the first opposing surface 111.

[0077] The second surface 121b included in the second opposing surface 121 does not have to be surrounded by the first surface 121a included in the second opposing surface 121. Similarly, when the first opposing surface 111 includes a first surface and a second surface, the second surface included in the first opposing surface 111 does not have to be surrounded by the first surface included in the first opposing surface 111.

[0078] At least one of the first actuator electrode 113, the first sensor electrode 114, the second actuator electrode 123, and the second sensor electrode 124 does not have to have a ring shape on the XY plane. Furthermore, the center of at least one of the first actuator electrode 113, the first sensor electrode 114, the second actuator electrode 123, and the second sensor electrode 124 does not have to coincide with the center of the portion 112 where the thickness that defines the membrane structure is relatively small.

[0079] In addition to or instead of the first substrate 11 being distorted, the second substrate 12 may be distorted. That is, in addition to or instead of the first substrate 11 being distorted, changing the distance between the first substrate 11 and the second substrate 12, the second substrate 12 may be distorted, changing the distance between the first substrate 11 and the second substrate 12. In other words, the second substrate 12 may function as a movable substrate that can substantially move. In this case, the first actuator electrode 113 and the second actuator electrode 123 may be electrodes for controlling the state of the second substrate 12 in addition to or instead of being electrodes for controlling the state of the first substrate 11. The first sensor electrode 114 and the second sensor electrode 124 may be electrodes for detecting the state of the second substrate 12 in addition to or instead of being electrodes for detecting the state of the first substrate 11.

[0080] In addition, when second substrate 12 is distorted, second substrate 12 preferably has a membrane structure similar to first substrate 11. However, even when second substrate 12 is distorted, second substrate 12 does not have to have a membrane structure similar to first substrate 11. Alternatively, even when second substrate 12 is not distorted, second substrate 12 may have a membrane structure similar to first substrate 11.

[0081] The state in which the distance d3 between the first sensor electrode 114 and the second sensor electrode 124 in the initial state is smaller than the distance d2 between the first actuator electrode 113 and the second actuator electrode 123 in the initial state may be achieved by a structure other than a step formed on the second opposing surface 121. For example, even if no step is formed on the second opposing surface 121, the state in which the distance d3 is smaller than the distance d2 may be achieved by sandwiching an intervening member between the second opposing surface 121 and the second sensor electrode 124. For example, the state in which the distance d3 is smaller than the distance d2 may be achieved by sandwiching an intervening member between the first opposing surface 111 and the first sensor electrode 124. For example, the state in which the distance d3 is smaller than the distance d2 may be achieved by making the thickness of the first sensor electrode 114 (i.e., the length along the Z-axis direction) larger than the thickness of the first actuator electrode 113. For example, by making the thickness of second sensor electrode 124 greater than the thickness of second actuator electrode 123, a state in which distance d3 is smaller than distance d2 may be realized.

[0082] However, the purpose of making the distance d3 smaller than the distance d2 is mainly to distort the first substrate 11 while detecting the distance between the first substrate 11 and the second substrate 12. Therefore, from the viewpoint of achieving the technical effect achieved mainly by electrically isolating the first actuator electrode 113 and the first sensor electrode 114 and electrically isolating the second actuator electrode 123 and the second sensor electrode 124 (i.e., the technical effect of being able to simplify the circuit configurations of the drive signal processing circuit that performs signal processing for distorting the first substrate 11 and the detection signal processing circuit that performs signal processing for detecting the distance between the first substrate 11 and the second substrate 12), the distance d3 does not have to be smaller than the distance d2. For example, the distance d3 and the distance d2 may be the same. The distance d3 may also be larger than the distance d2.

[0083] The first actuator electrode 113 and the first sensor electrode 114 may be electrically isolated, while the second actuator electrode 123 and the second sensor electrode 124 may not be electrically isolated. In other words, the first actuator electrode 113 and the first sensor electrode 114 may not be electrically connected, while the second actuator electrode 123 and the second sensor electrode 124 may be electrically connected. Even in this case, the actuator 1 can handle the potential of the second actuator electrode 123 and the potential of the second sensor electrode 124 as a common potential, thereby handling the drive signal and the detection signal in a state where these two types of signals are electrically isolated.

[0084] Alternatively, the first actuator electrode 113 and the first sensor electrode 114 may not be electrically isolated, while the second actuator electrode 123 and the second sensor electrode 124 may be electrically isolated. In other words, the first actuator electrode 113 and the first sensor electrode 114 may be electrically connected, while the second actuator electrode 123 and the second sensor electrode 124 may not be electrically connected. Even in this case, the actuator 1 can handle the potential of the first actuator electrode 113 and the potential of the first sensor electrode 114 as a common potential, thereby handling the drive signal and the detection signal in a state where these two types of signals are electrically isolated.

[0085] However, the purpose of electrically isolating the first actuator electrode 113 and the first sensor electrode 114 and / or the second actuator electrode 123 and the second sensor electrode 124 is mainly to simplify the circuit configuration of the drive signal processing circuit that performs signal processing for distorting the first substrate 11 and the detection signal processing circuit that performs signal processing for detecting the gap between the first substrate 11 and the second substrate 12. Therefore, from the perspective of the main purpose being the technical effect achieved mainly by making the gap d3 smaller than the gap d2 (that is, the technical effect of being able to distort the first substrate 11 while detecting the gap between the first substrate 11 and the second substrate 12), it is not necessary for the first actuator electrode 113 and the first sensor electrode 114 to be electrically isolated, and the second actuator electrode 123 and the second sensor electrode 124 to be electrically isolated.

[0086] (2) Second Example Next, the actuator 2 of the second embodiment will be described with reference to FIGS. 3(a) and 3(b). FIG. 3(a) is a top view of the actuator 2 of the second embodiment. FIG. 3(b) is a cross-sectional view of the actuator 2 of the second embodiment shown in FIG. 3(a) taken along line III-III'. Note that in FIGS. 3(a) and 3(b), as in FIGS. 1(a) to 1(c), the description will be given using an example in which the actuator 3 is arranged in a virtual three-dimensional space. Furthermore, the same components as those included in the actuator 1 of the first embodiment will be assigned the same reference numerals, and detailed description thereof will be omitted.

[0087] As shown in FIGS. 3(a) and 3(b), the actuator 2 of the second embodiment differs from the actuator 1 of the first embodiment, in that the second opposing surface 221 of the second substrate 22 has a plurality of second surfaces 221b (i.e., second surface 221b-1 and second surface 221b-2). The second surface 221b-1 protrudes toward the first substrate (in other words, toward the +Z-axis direction) compared to the second surface 221b-2. In other words, the second opposing surface 221 essentially has a plurality of steps. Other features of the second opposing surface 221 of the second embodiment may be the same as those of the second opposing surface 121 of the first embodiment.

[0088] Furthermore, the actuator 2 of the second embodiment differs from the actuator 1 of the first embodiment in that a plurality of first sensor electrodes 214 (i.e., first sensor electrode 214-1 and first sensor electrode 214-2) are formed on the first opposing surface 121, which does not necessarily mean that a plurality of first sensor electrodes 114 are formed on the first opposing surface 111. Note that other characteristics of each of the first sensor electrode 214-1 and first sensor electrode 214-2 of the second embodiment may be the same as other characteristics of the first sensor electrode 114 of the first embodiment.

[0089] Furthermore, the actuator 2 of the second embodiment differs from the actuator 1 of the first embodiment in that a plurality of second sensor electrodes 224 (i.e., second sensor electrode 224-1 and second sensor electrode 224-2) are formed on the second opposing surface 221, which does not necessarily include a plurality of second sensor electrodes 124 formed on the second opposing surface 121. Specifically, the second sensor electrode 224-1 facing the first sensor electrode 214-1 is formed on the second surface 221b-1. Furthermore, the second sensor electrode 224-2 facing the first sensor electrode 214-2 is formed on the second surface 221b-2. As a result, the distance d31 between the first sensor electrode 214-1 and the second sensor electrode 224-1 in the initial state is smaller than the distance d32 between the first sensor electrode 214-2 and the second sensor electrode 224-2 in the initial state. That is, the actuator 2 of the second embodiment includes a plurality of combinations of mutually opposing first sensor electrodes 214 and second sensor electrodes 224. Furthermore, the distance d3 between the first sensor electrode 214 and the second sensor electrode 224 in the initial state for each combination is different from each other. Note that other features of each of the second sensor electrodes 224-1 and 224-2 of the second embodiment may be the same as other features of the second sensor electrode 124 of the first embodiment.

[0090] Other components of the actuator 2 of the second embodiment may be the same as other components of the actuator 1 of the first embodiment.

[0091] The actuator 2 of the second embodiment described above can also preferably enjoy the various effects enjoyed by the actuator 1 of the first embodiment. In addition, the actuator 2 of the second embodiment can appropriately change the combination of the first sensor electrodes 214 and the second sensor electrodes 224 used to detect the gap between the first substrate 11 and the second substrate 22 as needed. Below, an operation for appropriately changing the combination of the first sensor electrodes 214 and the second sensor electrodes 224 used to detect the gap between the first substrate 11 and the second substrate 22 will be described.

[0092] As described in the first embodiment, in order to improve the detection accuracy of the gap between the first substrate 11 and the second substrate 22, it is preferable that the gap d3 between the first sensor electrode 114 and the second sensor electrode 124 in the initial state be relatively small. However, if the gap d3 between the first sensor electrode 114 and the second sensor electrode 124 in the initial state is relatively small, the first sensor electrode 114 and the second sensor electrode 124 are more likely to come into contact with each other when the amount of distortion of the first substrate 11 becomes relatively large. In this case, a technical problem arises in that it becomes difficult to detect the gap between the first substrate 11 and the second substrate 22 using the first sensor electrode 114 and the second sensor electrode 124 that have come into contact with each other.

[0093] Therefore, the actuator 2 of the second embodiment solves this technical problem by changing the combination of the first sensor electrodes 214 and the second sensor electrodes 224 used to detect the distance between the first substrate 11 and the second substrate 22. For example, when the amount of distortion of the first substrate 11 is relatively small, the actuator 2 detects the distance between the first substrate 11 and the second substrate 22 using the first sensor electrode 214-1 and the second sensor electrode 224-1, which are spaced relatively apart in the initial state. On the other hand, when the amount of distortion of the first substrate 11 becomes relatively large and the possibility of the first sensor electrode 214-1 and the second sensor electrode 224-1 coming into contact with each other becomes relatively high, the actuator 2 detects the distance between the first substrate 11 and the second substrate 22 using the first sensor electrode 214-2 and the second sensor electrode 224-2, which are spaced relatively apart in the initial state, instead of the first sensor electrode 214-1 and the second sensor electrode 224-1, which are spaced relatively apart in the initial state. As a result, the actuator 2 can detect the distance between the first substrate 11 and the second substrate 22 regardless of the amount of distortion of the first substrate 11.

[0094] 3, two first sensor electrodes 214 are formed on the first opposing surface 111, and two second sensor electrodes 224 are formed on the second opposing surface 221. However, three or more first sensor electrodes 214 may be formed on the first opposing surface 111, and three or more second sensor electrodes 224 may be formed on the second opposing surface 221. In this case, it is preferable that three or more steps are formed on the second opposing surface 221, and three or more second surfaces 221b are formed on which corresponding second sensor electrodes 224 are formed.

[0095] (3) Third Example Next, the actuator 3 of the third embodiment will be described with reference to FIGS. 4(a) and 4(b). FIG. 4(a) is a top view of the actuator 3 of the third embodiment. FIG. 4(b) is a cross-sectional view of the actuator 3 of the third embodiment shown in FIG. 4(a) taken along line IV-IV'. Note that in FIGS. 4(a) and 4(b), as in FIGS. 1(a) to 1(c), the description will be given using an example in which the actuator 3 is arranged in a virtual three-dimensional space. Furthermore, the same components as those included in the actuator 1 of the first embodiment to the actuator 2 of the second embodiment will be assigned the same reference numerals, and detailed description thereof will be omitted.

[0096] 4(a) and 4(b), the actuator 3 of the third embodiment differs from the actuator 2 of the second embodiment in that the shapes of the first sensor electrodes 314-1 and 314-2 and the second sensor electrodes 324-1 and 324-2 are different from the shapes of the first sensor electrodes 214-1 and 214-2 and the second sensor electrodes 224-1 and 224-2. Specifically, the first sensor electrodes 314-1 and 314-2 and the second sensor electrodes 324-1 and 324-2 are circular, which differs from the first sensor electrodes 214-1 and 214-2 and the second sensor electrodes 224-1 and 224-2, which are ring-shaped. Other components of the actuator 3 of the third embodiment may be the same as other components of the actuator 2 of the second embodiment.

[0097] The actuator 3 of the third embodiment can also preferably enjoy the various effects that the actuator 2 of the second embodiment enjoys.

[0098] The shapes of the first surface 121a and the second surfaces 221b-1 and 221b-2 included in the second opposing surface 221 may be changed as appropriate to match the shapes of the second sensor electrodes 324-1 and 324-2. In other words, the second opposing surface 221 may include a second surface 221b-1 having any shape on which the second sensor electrode 324-1 can be formed, a second surface 221b-2 having any shape on which the second sensor electrode 324-2 can be formed, and a first surface 121a other than the second surfaces 221b-1 and 221b-2.

[0099] (4) Fourth Example Next, the actuator 4 of the fourth embodiment will be described with reference to FIGS. 5(a) and 5(b). FIG. 5(a) is a top view of the actuator 4 of the fourth embodiment. FIG. 5(b) is a V-V' cross-sectional view of the actuator 4 of the fourth embodiment shown in FIG. 5(a). Note that, in FIGS. 5(a) and 5(b), as in FIGS. 1(a) to 1(c), the description will be given using an example in which the actuator 4 is arranged in a virtual three-dimensional space. Furthermore, the same components as those included in the actuator 1 of the first embodiment to the actuator 3 of the third embodiment will be assigned the same reference numerals, and detailed description thereof will be omitted.

[0100] 5(a) and 5(b), the actuator 4 of the fourth embodiment differs from the actuator 1 of the first embodiment in that the shape and material of the first sensor electrode 414 and the second sensor electrode 424 are different from the shape and material of the first sensor electrode 114 and the second sensor electrode 124. Specifically, the first sensor electrode 414 and the second sensor electrode 424 have a circular shape on the XY plane, which differs from the first sensor electrode 114 and the second sensor electrode 124, which may or may not have a circular shape. The first sensor electrode 414 and the second sensor electrode 424 are semi-transparent films, which differ from the first sensor electrode 114 and the second sensor electrode 124, which may not necessarily be semi-transparent films.

[0101] Additionally, the actuator 4 of the fourth embodiment differs from the actuator 1 of the first embodiment in that at least a portion 415 of the first substrate 41 where the first sensor electrode 414 is formed has semi-transparency (in other words, light transmissivity), whereas the portion of the first substrate 11 where at least the first sensor electrode 114 is formed does not necessarily have semi-transparency. The actuator 4 of the fourth embodiment also differs from the actuator 1 of the first embodiment in that at least a portion of the second substrate 42 where at least the second sensor electrode 424 is formed has semi-transparency 425.

[0102] Other components of the actuator 4 of the fourth embodiment may be the same as other components of the actuator 1 of the first embodiment.

[0103] The actuator 4 of the fourth embodiment can also preferably enjoy the various effects enjoyed by the actuator 1 of the first embodiment. In addition, the actuator 4 of the fourth embodiment can be used as a so-called Fabry-Perot type spectroscopic element.

[0104] The first sensor electrode 414 does not have to have a circular shape on the XY plane. However, it is preferable that the first sensor electrode 414 has a shape that can cover the area through which light passes. The second sensor electrode 424 does not have to have a circular shape on the XY plane. It is preferable that the second sensor electrode 424 has a shape that can cover the area through which light passes.

[0105] (5) Fifth Example Next, the actuator 5 of the fifth embodiment will be described with reference to FIGS. 6(a) and 6(b). FIG. 6(a) is a top view of the actuator 5 of the fifth embodiment. FIG. 6(b) is a cross-sectional view taken along line VI-VI' of the actuator 5 of the fifth embodiment shown in FIG. 6(a). Note that, in FIGS. 6(a) and 6(b), as in FIGS. 1(a) to 1(c), the description will be given using an example in which the actuator 5 is arranged in a virtual three-dimensional space. Furthermore, the same components as those included in the actuator 1 of the first embodiment to the actuator 4 of the fourth embodiment will be assigned the same reference numerals, and detailed description thereof will be omitted.

[0106] As shown in Figures 6(a) and 6(b), the actuator 5 of the fifth embodiment differs from the actuator 1 of the first embodiment, in that the first actuator electrode 513 is divided into a plurality of first actuator electrode portions 513a to 513d, whereas the first actuator electrode 113 is not necessarily divided. The actuator 5 of the fifth embodiment also differs from the actuator 1 of the first embodiment, in that the second actuator electrode 523 is divided into a plurality of second actuator electrode portions 523a to 523d, whereas the second actuator electrode 123 is not necessarily divided. The actuator 5 of the fifth embodiment also differs from the actuator 1 of the first embodiment, in that the first sensor electrode 514 is divided into a plurality of first sensor electrode portions 514a to 514d, whereas the first sensor electrode 114 is not necessarily divided. Furthermore, the actuator 5 of the fifth embodiment differs from the actuator 1 of the first embodiment in that the second sensor electrode 524 is divided into a plurality of second sensor electrode portions 524a to 524d, whereas the second sensor electrode 124 is not necessarily divided. Note that other features of the first actuator electrode 513 and the second actuator electrode 523 and the first sensor electrode 514 and the second sensor electrode 524 of the second embodiment may be the same as other features of the first actuator electrode 113 and the second actuator electrode 123 and the first sensor electrode 114 and the second sensor electrode 124 of the first embodiment, respectively.

[0107] The multiple first actuator electrode portions 513a to 513d are distributed in a plane along the XY plane (that is, in a plane perpendicular to the direction in which the first substrate 11 and the second substrate 12 face each other, or in a plane along the surface of the first substrate 11 or the second substrate 12). Furthermore, the multiple first actuator electrode portions 513a to 513d are preferably electrically isolated from each other.

[0108] Similarly, the second actuator electrode portions 523a to 523d are also distributed in a plane along the XY plane. Furthermore, the second actuator electrode portions 523a to 523d are preferably electrically isolated from one another.

[0109] Similarly, the first sensor electrode portions 514a to 514d are also distributed in a plane along the XY plane. Furthermore, the first sensor electrode portions 514a to 514d are preferably electrically isolated from each other.

[0110] Similarly, the second sensor electrode portions 524a to 524d are also distributed in a plane along the XY plane. Furthermore, the second sensor electrode portions 524a to 524d are preferably electrically isolated from each other.

[0111] Other components included in the actuator 5 of the fifth embodiment may be the same as other components included in the actuator 1 of the first embodiment.

[0112] The actuator 5 of the fifth embodiment described above can also preferably enjoy the various effects enjoyed by the actuator 1 of the first embodiment. In addition, the actuator 5 of the fifth embodiment can detect the tilt (in other words, the inclination) of at least one of the first substrate 11 and the second substrate 12, and control the amount of distortion of the first substrate 11 so as to correct the tilt. Below, an operation of detecting the tilt of at least one of the first substrate 11 and the second substrate 12 and controlling the amount of distortion of the first substrate 11 so as to correct the tilt will be described.

[0113] In the actuator 5 of the fifth embodiment, the first sensor electrode 514 is divided into a plurality of first sensor electrode portions 514a to 514d, and the second sensor electrode 524 is divided into a plurality of second sensor electrode portions 524a to 524d. Therefore, the capacitances of the first sensor electrode 514 and the second sensor electrode 524 are individually detected as follows: (i) the capacitance of the first sensor electrode portion 514a and the second sensor electrode portion 524a, (ii) the capacitance of the first sensor electrode portion 514b and the second sensor electrode portion 524b, (iii) the capacitance of the first sensor electrode portion 514c and the second sensor electrode portion 524c, and (iv) the capacitance of the first sensor electrode portion 514d and the second sensor electrode portion 524d. As a result, in the fifth embodiment, the following distances between the first sensor electrode 514 and the second sensor electrode 524 are individually detected: (i) distance d3a between the first sensor electrode portion 514a and the second sensor electrode portion 524a; (ii) distance d3b between the first sensor electrode portion 514b and the second sensor electrode portion 524b; (iii) distance d3c between the first sensor electrode portion 514c and the second sensor electrode portion 524c; and (iv) distance d3d between the first sensor electrode portion 514d and the second sensor electrode portion 524d. If at least one of the first substrate 11 and the second substrate 12 is tilted (i.e., inclined), there is a high possibility that a deviation will occur in at least two of the distances d3a to d3d. Therefore, a detection signal processing circuit (not shown) can detect the tilt of at least one of the first substrate 11 and the second substrate 12 by detecting the distances d3a to d3d.

[0114] On the other hand, in the actuator 5 of the fifth embodiment, the first actuator electrode 513 is divided into a plurality of first actuator electrode portions 513a to 513d, and the second actuator electrode 523 is divided into a plurality of second actuator electrode portions 523a to 523d. Therefore, a drive signal processing circuit (not shown) can individually adjust the drive signal Sa supplied to the first actuator electrode portion 513a and the second actuator electrode portion 523a, the drive signal Sb supplied to the second actuator electrode portion 513b and the second actuator electrode portion 523b, the drive signal Sc supplied to the first actuator electrode portion 513c and the second actuator electrode portion 523c, and the drive signal Sd supplied to the first actuator electrode portion 513d and the second actuator electrode portion 523d. As a result, the amount of distortion of the first substrate 11 is appropriately adjusted so as to correct the detected tilt.

[0115] Furthermore, the aspects that can be adopted by at least one of the actuators 1 of the first embodiment to 5 of the fifth embodiment described above may also be adopted by at least another of the actuators 1 of the first embodiment to 5 of the fifth embodiment.

[0116] The present invention is not limited to the above-described embodiments, but can be modified as appropriate within the scope of the claims and the gist or concept of the invention as can be read from the entire specification, and actuators with such modifications are also included in the technical scope of the present invention. [Explanation of symbols]

[0117] 1, 2, 3, 4, 5 Actuators 11, 41 First board 111 First opposing surface 113, 513 First actuator electrode 114, 214, 314, 414, 514 First sensor electrode 12, 22, 42 Second board 121, 221 Second opposing surface 123, 523 Second actuator electrode 124, 224, 324, 424, 524 Second sensor electrode

Claims

1. A first member; a second member facing the first member; Equipped with a first control electrode and a first detection electrode are formed on a first opposing surface of the first member that faces the second member; a second control electrode facing the first control electrode and a second detection electrode facing the first detection electrode are formed on a second opposing surface of the second member that faces the first member, the first control electrode and the first detection electrode and / or the second control electrode and the second detection electrode are electrically isolated from each other; one of the first detection electrodes and another of the first detection electrodes are formed on the first opposing surface, the second opposing surface is formed with one of the second detection electrodes opposing the one of the first detection electrodes and another of the second detection electrodes opposing the other of the first detection electrodes; An initial distance between the one first detection electrode and the one second detection electrode is different from an initial distance between the other first detection electrode and the other second detection electrode. An actuator characterized by:

2. the first and second detection electrodes are electrodes for detecting a state of at least one of the first and second members, Switching between a first detection mode in which a state is detected using the one first detection electrode and the one second detection electrode and a second detection mode in which a state is detected using the other first detection electrode and the other second detection electrode.

2. The actuator according to claim 1,

3. the first and second control electrodes are electrodes for controlling the state of at least one of the first and second members, The first and second detection electrodes are electrodes for detecting the state of at least one of the first and second members.

3. The actuator according to claim 1 or 2.

4. An initial distance between the first detection electrode and the second detection electrode is smaller than an initial distance between the first control electrode and the second control electrode.

4. The actuator according to claim 1, wherein the actuator is a flexible member.

5. The first detection electrode and the second detection electrode are semi-transparent films.

5. The actuator according to claim 1, wherein the actuator is a flexible member.

6. the first detection electrode is divided into a plurality of first electrode portions distributed on a virtual plane intersecting a direction in which the first member and the second member face each other, The second detection electrode is divided into a plurality of second electrode portions distributed on an imaginary plane intersecting the direction in which the first member and the second member face each other.

6. The actuator according to claim 1, wherein the actuator is a rotatable actuator.

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