Patent Description:
There is known a soft actuator that performs mechanical work by using deformation of a flexible member as power (for example, Patent Literature <NUM>).

Patent Literature <NUM> discloses an actuator in which an electroactive polymer is sandwiched between a pair of electrodes. In the actuator disclosed in Patent Literature <NUM>, the electrodes as a pair are attracted to each other due to the Coulomb force of the charges stored by the voltage applied across the pair of electrodes, and the electroactive polymer deforms, thereby generating a displacement between the electrodes. <CIT> discloses an electrostatic actuator. <CIT> discloses a multi-motion micromirror. <CIT> discloses a programmable micromirror motion control system.

However, the actuator disclosed in Patent Literature <NUM> can achieve movement with only one degree of freedom in a direction along the interelectrode distance or a direction along the electrodes. To achieve movement with multiple degrees of freedom by the actuator disclosed in Patent Literature <NUM>, two or more actuators need to be combined, which may cause a device to have a complicated structure.

The present invention has been made in view of the foregoing, and provides a novel actuator that can easily achieve movement with multiple degrees of freedom.

In view of the foregoing, the actuator according to the present invention is defined by claim <NUM>.

With such a configuration, the actuator according to the present invention can cause dielectric polarization of the first insulating layer provided in the first base electrode by the voltage applied across the first base electrode and the flexible electrode and generate a Coulomb force between the first insulating layer and the flexible electrode. The actuator can cause the flexible electrode to deform along the first axis by using the effect of the Coulomb force generated between the first insulating layer and the flexible electrode. In the same manner, the actuator can cause dielectric polarization of the second insulating layer provided in the second base electrode by the voltage applied across the second base electrode and the flexible electrode and generate a Coulomb force between the second insulating layer and the flexible electrode. The actuator can cause the flexible electrode to deform along the second axis by using the effect of the Coulomb force generated between the second insulating layer and the flexible electrode. The actuator can cause the output members to be displaced along the first axis and the second axis according to the deformation of the flexible electrode along the first axis and the second axis, respectively. Therefore, with only one actuator provided with one flexible electrode, the actuator according to the present invention can easily achieve movement with multiple degrees of freedom, even without combining two or more actuators.

In addition, the actuator according to the present invention can detect a deformation amount of the flexible electrode by detecting an amount of electric charge stored in the flexible electrode and can detect a displacement amount of the output member by using a known method. That is, the actuator can detect the displacement amount of the output member without newly introducing a detection device separate from the actuator. Therefore, the actuator according to the present invention can control the movement with multiple degrees of freedom with a simple configuration.

In some embodiments, the first base electrode and the second base electrode each include a plurality of electrode portions adapted to independently receive the voltage.

With such an aspect, since the first base electrode can control the voltage applied across the first base electrode and the flexible electrode for each of the plurality of electrode portions, the first base electrode can control the Coulomb force acting on the flexible electrode for each of the plurality of electrode portions. Accordingly, the first base electrode can cause the flexible electrode to deform in a more complicated and fine manner as compared to the first base electrode not including the plurality of electrode portions, thus allowing the output member to be displaced in a complicated and fine manner. Likewise, also when the second base electrode is formed of the plurality of electrode portions as described above, the second base electrode can cause the output member to be displaced in a complicated and fine manner. Therefore, the actuator can easily achieve complicated and fine movement with multiple degrees of freedom.

In some embodiments, each of the plurality of electrode portions has an inclined face that faces the flexible electrode and is inclined with respect to the flexible electrode, and the inclined faces of the plurality of electrode portions are inclined in directions different from each other.

With such an aspect, the first base electrode can cause the flexible electrode to deform toward each of the plurality of inclined faces that are inclined in the directions different from each other with respect to the flexible electrode. Accordingly, the first base electrode can cause the output member to be displaced so as to rotate in the direction crossing the first axis. In particular, by alternately applying a voltage and stopping application of the voltage between one of the plurality of electrode portions and the other one of the plurality of electrode portions, the first base electrode can switch the deformation direction of the flexible electrode between the direction toward the inclined face of the one electrode portion and the direction toward the inclined face of the other electrode portion alternately. Accordingly, the first base electrode can cause the output member to be displaced so as to swing in the direction crossing the first axis. Likewise, also when the plurality of electrode portions forming the second base electrode has the inclined faces as described above, the second base electrode can cause the output member to be displaced so as to rotate or swing in the direction crossing the second axis. Therefore, the actuator can easily achieve various types of movement, in addition to the transitional movement along the first axis or the second axis.

In some embodiments, the plurality of electrode portions forming the first base electrode is disposed along a direction rotating about the first axis, and the plurality of electrode portions forming the second base electrode is disposed along a direction rotating about the second axis.

With such an aspect, the first base electrode can sequentially apply a voltage or sequentially stop application of the voltage across the first base electrode and the flexible electrode for each of the plurality of electrode portions along the direction rotating about the first axis. The first base electrode can sequentially cause the flexible electrode to deform toward each of the plurality of electrode portions disposed along the direction rotating about the first axis. Accordingly, the first base electrode can cause the output member to be displaced so as to precess about the first axis as a rotation axis. Likewise, also when the second base electrode is formed of a plurality of electrode portions as described above, the second base electrode can cause the output member to be displaced so as to precess about the second axis as a rotation axis. Therefore, the actuator can easily achieve various types of movement, in addition to the transitional movement along the first axis or the second axis.

In some embodiments, the flexible electrode has a hollow structure.

With such an aspect, the flexible electrode can deform more easily as compared to the flexible electrode with a solid structure. Accordingly, the actuator can cause the flexible electrode to deform even if a voltage applied to the flexible electrode is reduced. This can reduce power consumption and easily ensure insulation, and thus can increase safety. In addition, the actuator can reduce its weight and cost as compared to the one in which the flexible electrode has a solid structure. Therefore, the actuator can achieve movement with multiple degrees of freedom more easily and safely.

In some embodiments, the actuator further includes a movable base electrode disposed opposite to the first base electrode with at least a portion of the flexible electrode interposed therebetween on the first axis and adapted to move along the first axis with respect to the first base electrode, in which the movable base electrode is provided with an insulating layer on an opposite face facing the flexible electrode, and a space is formed between the insulating layer of the movable base electrode and the flexible electrode, in which the movable base electrode moves by a voltage applied across the movable base electrode and the flexible electrode.

With such an aspect, the actuator can cause the Coulomb force generated between the insulating layer of the first base electrode and the flexible electrode to act on the flexible electrode. In addition, the actuator can cause the Coulomb force generated between the insulating layer of the movable base electrode and the flexible electrode to act on the flexible electrode. The direction of the Coulomb force generated between the insulating layer of the movable base electrode and the flexible electrode is equal to the direction of the Coulomb force generated between the first insulating layer of the first base electrode and the flexible electrode. That is, the actuator can enhance the Coulomb force that causes the flexible electrode to deform along the first axis. Since the actuator can enhance the power to cause the output member to be displaced along the first axis, it can have a higher output in the direction along the first axis. Therefore, the actuator can easily achieve movement with multiple degrees of freedom and can also increase an output.

In some embodiments, the flexible electrode is formed into a hexahedron, the hexahedron including a first face crossing the first axis, a second face facing the first face on the first axis, a third face crossing the second axis, and a fourth face facing the third face on the second axis, the opposite face of the first base electrode facing the flexible electrode faces the first face, the first space is formed between the first insulating layer provided on the opposite face of the first base electrode facing the flexible electrode and the first face, the opposite face of the second base electrode facing the flexible electrode faces the third face, the second space is formed between the second insulating layer provided on the opposite face of the second base electrode facing the flexible electrode and the third face, and the output member includes a first output member attached to the second face and a second output member attached to the fourth face.

With such an aspect, the actuator can cause the first output member and the second output member to be displaced along the first axis and the second axis, respectively, even with a simple structure including the flexible electrode, the first base electrode, and the second base electrode. Therefore, the actuator can more easily achieve movement with multiple degrees of freedom.

In some embodiments, the actuator further includes a third base electrode disposed to face the flexible electrode on a third axis crossing each of the first axis and the second axis and provided with a third insulating layer on an opposite face facing the flexible electrode, in which a third space is formed between the third insulating layer and the flexible electrode, in which the flexible electrode deforms toward the third insulating layer by a voltage applied across the third base electrode and the flexible electrode.

With such an aspect, the actuator can cause the flexible electrode to deform along the third axis in addition to the first axis and the second axis. The actuator can cause the output member to be displaced along the third axis in addition to the first axis and the second axis. Therefore, the actuator can easily achieve movement with greater degrees of freedom.

According to the present invention, a novel actuator that can easily achieve movement with multiple degrees of freedom can be provided.

In each of the embodiments, unless otherwise specified, the configuration denoted by the same reference numeral has the same function in the embodiments, and descriptions thereof will be omitted. In addition, orthogonal coordinate axes including the X-axis, Y-axis, and Z-axis are shown in the drawings as appropriate in order to clarify the explanation of the position of each unit.

As illustrated in <FIG>, the origin of the orthogonal coordinate axes is the center of a flexible electrode <NUM> described later. However, the orthogonal coordinate axes may be shown in the margin of the drawings for the sake of simplification of the drawings. The X-axis, Y-axis, and Z-axis respectively correspond to the "second axis," "first axis," and "third axis" recited in the claims as one example.

In the present embodiment, the direction rotating about the X-axis, the direction rotating about the Y-axis, and the direction rotating about the Z-axis may also be referred to as "pitch direction," "yaw direction," and "roll direction," respectively. In the present embodiment, a first base electrode <NUM>, a second base electrode <NUM>, and a third base electrode <NUM>, which will be described later, may also be collectively referred to as "base electrodes <NUM> to <NUM>. " In the present embodiment, a first output member <NUM>, a second output member <NUM>, and a third output member <NUM>, which will be described later, may also be collectively referred to as "output members <NUM> to <NUM>. " In addition, in the present embodiment, the expression "A faces B" may include not only the case where a face of A facing B is parallel with a face of B facing A, but also the case where a face of A facing B is not parallel with a face of B facing A.

An actuator <NUM> of the first embodiment will be described with reference to <FIG>.

<FIG> is a schematic view of the actuator <NUM> of the first embodiment. <FIG> is a view explaining the output members <NUM> to <NUM> provided in the actuator <NUM> illustrated in <FIG>. It should be noted that the illustration of the output members <NUM> to <NUM> is omitted in <FIG>, and the illustration of the base electrodes <NUM> to <NUM> is omitted in <FIG>.

The actuator <NUM> is a soft actuator that performs mechanical work by using, as power, deformation of the flexible electrode <NUM> that has flexibility. In the actuator <NUM>, the flexible electrode <NUM> itself deforms. This is different from the conventional soft actuator that uses, as power, deformation of a dielectric elastomer sandwiched between a pair of electrodes. The actuator <NUM> is applicable to various kinds of actuators used for artificial muscle or robots, for example.

The actuator <NUM> alone acts as an actuator that can achieve movement with multiple degrees of freedom. The actuator <NUM> can cause the flexible electrode <NUM> to three-dimensionally deform in the first axis, the second axis, and the third axis that cross each other when a voltage is applied across the base electrodes <NUM> to <NUM> and the flexible electrode <NUM>, respectively. The actuator <NUM> can cause the output members <NUM> to <NUM> attached to the flexible electrode <NUM> to be three-dimensionally displaced according to the deformation of the flexible electrode <NUM>, thus outputting work to the outside.

The actuator <NUM> includes the flexible electrode <NUM>, the base electrodes <NUM> to <NUM>, and the output members <NUM> to <NUM>.

The flexible electrode <NUM> is formed of a flexible electric conductor. The flexible electrode <NUM> has flexibility such that it deforms due to the effect of the Coulomb force generated by the voltage applied across the base electrodes <NUM> to <NUM> and the flexible electrode <NUM> and returns to the original shape when the application of the voltage is stopped.

Examples of the material used for the formation of the flexible electrode <NUM> may include conductive rubber or conductive gel, for example. Examples of the conductive rubber may include an elastomer formed by mixture with a conductive material. Examples of the conductive material may include fine powder of carbon black, acetylene black, or carbon nanotube, metal fine powder of silver or copper, conductive fine powder having a core-shell structure in which an insulator of silica or alumina, for example, is coated with metal through sputtering, for example. Examples of the conductive gel may include a functional gel material obtained by retaining a solvent such as water or a humectant, an electrolyte, an additive, and the like in a three-dimensional polymer matrix. Examples of the functional gel material may include Technogel (registered trademark) available from Sekisui Kasei Co. The flexible electrode <NUM> may be formed by using a viscoelastic body or an elasto-plastic body. In this case, the flexible electrode <NUM> may be used within a range assumed to be an elastic region, for example.

The flexible electrode <NUM> is formed into a three-dimensional shape. In the present embodiment, the flexible electrode <NUM> is formed into a polyhedron, for example, a hexahedron. The flexible electrode <NUM> of the present embodiment includes a first face <NUM> crossing the Y-axis and a second face <NUM> facing the first face <NUM> on the Y-axis. The flexible electrode <NUM> of the present embodiment includes a third face <NUM> crossing the X-axis and a fourth face <NUM> facing the third face <NUM> on the X-axis. The flexible electrode <NUM> of the present embodiment includes a fifth face <NUM> crossing the Z-axis and a sixth face <NUM> facing the fifth face <NUM> on the Z-axis. The flexible electrode <NUM> of the present embodiment may be formed into a three-dimensional shape such that the first face <NUM> and the second face <NUM> intersect the Y-axis, the third face <NUM> and the fourth face <NUM> intersect the X-axis, and the fifth face <NUM> and the sixth face <NUM> intersect the Z-axis.

The base electrodes <NUM> to <NUM> are formed of a rigid conductive material. Examples of the material used for the formation of the base electrodes <NUM> to <NUM> may include a metal material such as iron, copper, or aluminum. The base electrodes <NUM> to <NUM> each are formed into a plate shape. Alternatively, the base electrodes <NUM> to <NUM> each may be formed by coating with a conductive metal film, for example, one surface of a substrate formed by using a non-metal material having heat resistance, rigidity, and insulation, such as ceramics. The surface of the substrate coated with a metal film is a face facing the flexible electrode <NUM>.

The base electrodes <NUM> to <NUM> include the first base electrode <NUM>, the second base electrode <NUM>, and the third base electrode <NUM>.

The first base electrode <NUM> is an electrode for applying a voltage to generate a Coulomb force for causing the flexible electrode <NUM> to deform mainly along the Y-axis. The first base electrode <NUM> is disposed to face the flexible electrode <NUM> on the Y-axis. The first base electrode <NUM> has an opposite face <NUM> facing the flexible electrode <NUM>. In the present embodiment, the opposite face <NUM> facing the flexible electrode <NUM> faces the first face <NUM> of the flexible electrode <NUM>. The opposite face <NUM> facing the flexible electrode <NUM> is provided with first insulating layers 23a, 23b.

The first base electrode <NUM> may be formed of a plurality of electrode portions 25a, 25b. The plurality of electrode portions 25a, 25b is insulated from each other by a plate-like insulating portion <NUM>. With the plate-like insulating portion <NUM>, each of the plurality of electrode portions 25a, 25b may independently receive a voltage applied across the first base electrode <NUM> and the flexible electrode <NUM>. In the present embodiment, each of the plurality of electrode portions 25a, 25b is formed into a plate shape to extend along the Z-axis. The plurality of electrode portions 25a, 25b is arranged side by side along the X-axis. The plurality of electrode portions 25a, 25b is formed on the YZ plane in a manner symmetric with each other.

The plurality of electrode portions 25a, 25b respectively has inclined faces 22a, 22b that face the flexible electrode <NUM> and are inclined with respect to the flexible electrode <NUM>. That is, the opposite face <NUM> of the first base electrode <NUM> facing the flexible electrode <NUM> is formed of the inclined faces 22a, 22b. The inclined faces 22a, 22b are inclined with respect to the first face <NUM>. The inclined face 22a and the inclined face 22b are inclined in the directions different from each other. The expression "the inclined face 22a and the inclined face 22b are inclined in the directions different from each other" means that the normal of the inclined face 22a is not parallel with the normal of the inclined face 22b. In the present embodiment, the normal of the inclined face 22a is inclined in the -X-axis direction with respect to the Y-axis along the normal of the first face <NUM>. The normal of the inclined face 22b is inclined in the +X-axis direction with respect to the Y-axis along the normal of the first face <NUM>. The opposite face <NUM> facing the flexible electrode <NUM>, formed of the inclined faces 22a, 22b, protrudes in the +Y-axis direction and is formed into a crest shape having a ridge along the Z-axis.

The first insulating layers 23a, 23b are layers that insulate the first base electrode <NUM> from the flexible electrode <NUM>. The first insulating layer 23a coats the inclined face 22a of the electrode portion 25a that is one of the electrode portions forming the first base electrode <NUM>. The first insulating layer 23b coats the inclined face 22b of the electrode portion 25b that is the other one of the electrode portions forming the first base electrode <NUM>. The first insulating layers 23a, 23b are formed by using a ferroelectric material including ceramics to surely maintain the electric charge stored in the first base electrode <NUM> by the voltage applied across the first base electrode <NUM> and the flexible electrode <NUM>. In particular, the first insulating layers 23a, 23b are formed by using a ferroelectric material having a perovskite structure. Examples of the ferroelectric material having a perovskite structure may include barium titanate (BaTiO<NUM>), lead titanate (PbTiO<NUM>), lead zirconate titanate (Pb(Zr, Ti)O<NUM>), lanthanum lead zirconate titanate ((Pb, La)(Zr, Ti)O<NUM>), strontium titanate (SrTiOs), barium strontium titanate ((Ba, Sr)TiO<NUM>), or potassium sodium niobate ((NaK)NbO<NUM>). The barium titanate may contain dissolved therein a substance, such as CaZrO<NUM> or BaSnO<NUM>.

In addition, the material used for the formation of the first insulating layers 23a, 23b may have a high relative dielectric constant so as to generate a Coulomb force to cause the flexible electrode <NUM> to deform. The first insulating layers 23a, 23b may have a relative dielectric constant higher than or equal to <NUM> by employing ceramics (fine ceramics), for example. The barium titanate has a relative dielectric constant in the range from about <NUM> to <NUM>. The lead zirconate titanate has a relative dielectric constant in the range from <NUM> to <NUM>. The strontium titanate has a relative dielectric constant in the range from <NUM> to <NUM>. These ferroelectric materials with a perovskite structure have a high relative dielectric constant.

The first base electrode <NUM> is adapted to have a first space <NUM> formed between the first insulating layers 23a, 23b provided on the opposite face <NUM> of the first base electrode <NUM> facing the flexible electrode <NUM> and the flexible electrode <NUM>. In the present embodiment, the first space <NUM> is formed between the first insulating layers 23a, 23b provided on the opposite face <NUM> of the first base electrode <NUM> facing the flexible electrode <NUM> and the first face <NUM> of the flexible electrode <NUM>. In the actuator <NUM>, when a voltage is applied across the first base electrode <NUM> and the flexible electrode <NUM>, the voltage causes dielectric polarization of the first insulating layers 23a, 23b provided in the first base electrode <NUM>, and a Coulomb force is generated between the first insulating layers 23a, 23b and the flexible electrode <NUM>. The Coulomb force causes the flexible electrode <NUM> to deform toward the first insulating layers 23a, 23b so as to adhere to the first insulating layers 23a, 23b. The first space <NUM> is a space for the flexible electrode <NUM> to deform toward the first insulating layers 23a, 23b by the voltage applied across the first base electrode <NUM> and the flexible electrode <NUM>.

The second base electrode <NUM> is an electrode for applying a voltage to generate a Coulomb force for causing the flexible electrode <NUM> to deform mainly along the X-axis. The second base electrode <NUM> is configured in the same manner as the first base electrode <NUM>. That is, the second base electrode <NUM> is disposed to face the flexible electrode <NUM> on the X-axis. The second base electrode <NUM> has an opposite face <NUM> facing the flexible electrode <NUM>. In the present embodiment, the opposite face <NUM> facing the flexible electrode <NUM> faces the third face <NUM> of the flexible electrode <NUM>. The opposite face <NUM> facing the flexible electrode <NUM> is provided with second insulating layers 33a, 33b.

In the same manner as the first base electrode <NUM>, the second base electrode <NUM> may be formed of a plurality of electrode portions 35a, 35b. The plurality of electrode portions 35a, 35b is insulated from each other by a plate-like insulating portion <NUM> and each of the plurality of electrode portions 35a, 35b may independently receive a voltage applied across the second base electrode <NUM> and the flexible electrode <NUM>. In the same manner as the plurality of electrode portions 25a, 25b forming the first base electrode <NUM>, the plurality of electrode portions 35a, 35b respectively has inclined faces 32a, 32b that face the flexible electrode <NUM> and are inclined with respect to the flexible electrode <NUM>. The inclined faces 32a, 32b are inclined with respect to the third face <NUM>. The inclined face 32a and the inclined face 32b are inclined in the directions different from each other.

The second insulating layers 33a, 33b are layers that insulate the second base electrode <NUM> from the flexible electrode <NUM>. The second insulating layer 33a coats the inclined face 32a of the electrode portion 35a that is one of the electrode portions forming the second base electrode <NUM>. The second insulating layer 33b coats the inclined face 32b of the electrode portion 35b that is the other one of the electrode portions forming the second base electrode <NUM>. In the same manner as the first insulating layers 23a, 23b, the second insulating layers 33a, 33b are formed by using a ferroelectric material including ceramics, such as barium titanate, to surely maintain the electric charge stored in the second base electrode <NUM>, and having a high relative dielectric constant. A second space <NUM> is formed between the second insulating layers 33a, 33b and the flexible electrode <NUM>, in which the flexible electrode <NUM> deforms toward the second insulating layers 33a, 33b by the voltage applied across the second base electrode <NUM> and the flexible electrode <NUM>. In the present embodiment, the second space <NUM> is formed between the second insulating layers 33a, 33b provided on the opposite face <NUM> of the second base electrode <NUM> facing the flexible electrode <NUM> and the third face <NUM> of the flexible electrode <NUM>.

The third base electrode <NUM> is an electrode for applying a voltage to generate a Coulomb force for causing the flexible electrode <NUM> to deform mainly along the Z-axis. The third base electrode <NUM> is configured in the same manner as the first base electrode <NUM>. That is, the third base electrode <NUM> is disposed to face the flexible electrode <NUM> on the Z-axis. The third base electrode <NUM> has an opposite face <NUM> facing the flexible electrode <NUM>. In the present embodiment, the opposite face <NUM> facing the flexible electrode <NUM> faces the fifth face <NUM> of the flexible electrode <NUM>. The opposite face <NUM> facing the flexible electrode <NUM> is provided with third insulating layers 43a, 43b.

In the same manner as the first base electrode <NUM>, the third base electrode <NUM> may be formed of a plurality of electrode portions 45a, 45b. The plurality of plurality of electrode portions 45a, 45b is insulated from each other by a plate-like insulating portion <NUM> and each of the plurality of electrode portions 35a, 35b may independently receive a voltage applied across the third base electrode <NUM> and the flexible electrode <NUM>. In the same manner as the plurality of electrode portions 25a, 25b forming the first base electrode <NUM>, the plurality of electrode portions 45a, 45b respectively has inclined faces 42a, 42b that face the flexible electrode <NUM> and are inclined with respect to the flexible electrode <NUM>. The inclined faces 42a, 42b are inclined with respect to the fifth face <NUM>. The inclined face 42a and the inclined face 42b are inclined in the directions different from each other.

The third insulating layers 43a, 43b are layers that insulate the third base electrode <NUM> from the flexible electrode <NUM>. The third insulating layer 43a coats the inclined face 42a of the electrode portion 45a that is one of the electrode portions forming the third base electrode <NUM>. The third insulating layer 43b coats the inclined face 42b of the electrode portion 45b that is the other one of the electrode portions forming the third base electrode <NUM>. In the same manner as the first insulating layers 23a, 23b, the third insulating layers 43a, 43b are formed by using a ferroelectric material including ceramics. A third space <NUM> is formed between the third insulating layers 43a, 43b and the flexible electrode <NUM>, in which the flexible electrode <NUM> deforms toward the third insulating layers 43a, 43b by the voltage applied across the third base electrode <NUM> and the flexible electrode <NUM>. In the present embodiment, the third space <NUM> is formed between the third insulating layers 43a, 43b provided on the opposite face <NUM> of the third base electrode <NUM> facing the flexible electrode <NUM> and the fifth face <NUM> of the flexible electrode <NUM>.

The output members <NUM> to <NUM> are adapted to output work to the outside of the actuator <NUM>. The output members <NUM> to <NUM> are driven members attached to the flexible electrode <NUM> and adapted to be displaced according to the deformation of the flexible electrode <NUM>. It should be noted that the configuration of the output members <NUM> to <NUM> is not limited to the one illustrated in <FIG> below, but may be appropriately designed according to, for example, the environment of use of the actuator <NUM> including the specification of an external device that receives the work of the actuator <NUM>.

The output members <NUM> to <NUM> include the first output member <NUM>, the second output member <NUM>, and the third output member <NUM>.

The first output member <NUM> is a driven member adapted to be displaced according to the deformation of the flexible electrode <NUM> mainly along the Y-axis. In the present embodiment, the first output member <NUM> is attached to the second face <NUM> of the flexible electrode <NUM>. The first output member <NUM> may be formed by an output end <NUM> having a high rigidity coupled to the external device, a beam portion <NUM> having a high rigidity adapted to support the output end <NUM>, and a coupling portion <NUM> adapted to couple the beam portion <NUM> to the flexible electrode <NUM>.

The beam portion <NUM> is formed into a cross along a pair of diagonal lines of the square second face <NUM> and is disposed with a predetermined distance from the second face <NUM> in the +Y-axis direction. The output end <NUM> is formed in a rod shape so as to protrude in the +Y-axis direction from the intersection point of the cross-shaped beam portion <NUM>. The coupling portion <NUM> includes a horizontal portion <NUM>, which extends from each of the ends of the beam portion <NUM> in the axial direction of the beam portion <NUM>, and a vertical portion <NUM>, which extends from each of the vertexes of the second face <NUM> in the vertical direction (+Y-axis direction) of the second face <NUM> and is orthogonal to the horizontal portion <NUM>. The horizontal portion <NUM> may be formed by a member such as a damper that can be extended and retracted only in the axial direction of the horizontal portion <NUM>. The vertical portion <NUM> may be formed by an elastic member such as a spring that can elastically deform in a direction crossing the axial direction of the vertical portion <NUM>. A node <NUM> between the horizontal portion <NUM> and the vertical portion <NUM> may be a hinged node, rotation of which is not restricted, and may be formed by a ball joint, for example. A node <NUM> between the vertical portion <NUM> and the flexible electrode <NUM> may be a rigid node, rotation of which is restricted.

The second output member <NUM> is a driven member adapted to be displaced according to the deformation of the flexible electrode <NUM> mainly along the X-axis. In the present embodiment, the second output member <NUM> is attached to the fourth face <NUM> of the flexible electrode <NUM>. The second output member <NUM> is formed in the same manner as the first output member <NUM>. That is, the second output member <NUM> may be formed by an output end <NUM> coupled to the external device, a beam portion <NUM> adapted to support the output end <NUM>, and a coupling portion <NUM> adapted to couple the beam portion <NUM> to the flexible electrode <NUM>. The detailed configurations of the output end <NUM>, the beam portion <NUM>, and the coupling portion <NUM> of the second output member <NUM> are equal to those of the output end <NUM>, the beam portion <NUM>, and the coupling portion <NUM> of the first output member <NUM>, respectively. That is, the coupling portion <NUM> includes a horizontal portion <NUM>, which extends from each of the ends of the cross-shaped beam portion <NUM> in the axial direction of the beam portion <NUM>, and a vertical portion <NUM>, which extends from each of the vertexes of the fourth face <NUM> in the vertical direction (+X-axis direction) of the fourth face <NUM> and is orthogonal to the horizontal portion <NUM>. A node <NUM> between the horizontal portion <NUM> and the vertical portion <NUM> may be a hinged node, rotation of which is not restricted, and a node <NUM> between the vertical portion <NUM> and the flexible electrode <NUM> may be a rigid node, rotation of which is restricted.

The third output member <NUM> is a driven member adapted to be displaced according to the deformation of the flexible electrode <NUM> mainly along the Z-axis. In the present embodiment, the third output member <NUM> is attached to the sixth face <NUM> of the flexible electrode <NUM>. The third output member <NUM> is formed in the same manner as the first output member <NUM>. That is, the third output member <NUM> may be formed by an output end <NUM> coupled to the external device, a beam portion <NUM> adapted to support the output end <NUM>, and a coupling portion <NUM> adapted to couple the beam portion <NUM> to the flexible electrode <NUM>. The detailed configurations of the output end <NUM>, the beam portion <NUM>, and the coupling portion <NUM> of the third output member <NUM> are equal to those of the output end <NUM>, the beam portion <NUM>, and the coupling portion <NUM> of the first output member <NUM>, respectively. That is, the coupling portion <NUM> includes a horizontal portion <NUM>, which extends from each of the ends of the cross-shaped beam portion <NUM> in the axial direction of the beam portion <NUM>, and a vertical portion <NUM>, which extends from each of the vertexes of the sixth face <NUM> in the vertical direction (+Z-axis direction) of the sixth face <NUM> and is orthogonal to the horizontal portion <NUM>. A node <NUM> between the horizontal portion <NUM> and the vertical portion <NUM> may be a hinged node, rotation of which is not restricted, and a node <NUM> between the vertical portion <NUM> and the flexible electrode <NUM> may be a rigid node, rotation of which is restricted.

<FIG> is a view explaining a drive circuit <NUM> of the actuator <NUM> illustrated in <FIG>. It should be noted that the illustration of the second base electrode <NUM>, the third base electrode <NUM>, and the output members <NUM> to <NUM> is omitted in <FIG> schematically illustrates the cross section in XY plane of the flexible electrode <NUM> and the first base electrode <NUM> illustrated in <FIG>.

The drive circuit <NUM> is an electric circuit for driving the actuator <NUM>. The drive circuit <NUM> is adapted to drive the actuator <NUM> by applying a voltage across the base electrodes <NUM> to <NUM> and the flexible electrode <NUM>. <FIG> illustrates only the drive circuit <NUM> adapted to apply a voltage across the first base electrode <NUM> and the flexible electrode <NUM>. The drive circuit <NUM> adapted to apply a voltage across the second base electrode <NUM> or the third base electrode <NUM> and the flexible electrode <NUM> is configured in the same manner as the drive circuit <NUM> adapted to apply a voltage across the first base electrode <NUM> and the flexible electrode <NUM>. Thus, the descriptions thereof will be omitted.

The drive circuit <NUM> includes a power supply <NUM> formed by a direct voltage source, for example, a wire <NUM> adapted to couple the elements of the drive circuit <NUM> and the actuator <NUM>, switches 83a, 83b, 84a, 84b, <NUM> formed by semiconductor elements, for example, and a control unit <NUM> formed by an integrated circuit, for example.

One of the positive terminal and the negative terminal of the power supply <NUM> is coupled to the flexible electrode <NUM> by the wire <NUM>, and the other one of the positive terminal and the negative terminal of the power supply <NUM> is coupled to the first base electrode <NUM> by the wire <NUM>. The other one of the positive terminal and the negative terminal of the power supply <NUM> is coupled to the electrode portion 25a and the electrode portion 25b forming the first base electrode <NUM> that are in parallel to each other. The switch 83a is coupled between the electrode portion 25a and the power supply <NUM>. The switch 83b is coupled between the electrode portion 25b and the power supply <NUM>. The switch 84a is coupled between the electrode portion 25a and the frame ground (or earth). The switch 84b is coupled between the electrode portion 25b and the frame ground (or earth). The switch <NUM> is coupled between the flexible electrode <NUM> and the frame ground (or earth). That is, the electrode portions 25a, 25b and the flexible electrode <NUM> are coupled to the frame ground (or earth) via the switches 84a, 84b, <NUM>, respectively. It should be noted that the power supply <NUM> may be provided for each of the electrode portion 25a and the electrode portion 25b individually.

The control unit <NUM> is a circuit for controlling the elements of the drive circuit <NUM>. The control unit <NUM> is adapted to control the switches 83a, 83b, 84a, 84b, <NUM> so as to apply a voltage or stop application of the voltage across each of the electrode portions 25a, 25b and the flexible electrode <NUM>. The control unit <NUM> is adapted to independently control the ON/OFF state of the switch 83a and the ON/OFF state of the switch 83b. The control unit <NUM> is adapted to independently control the ON/OFF state of the switch 84a, the ON/OFF state of the switch 84b, and the ON/OFF state of the switch <NUM>. For example, when the switch 83a is controlled to be in the ON state, the power supply <NUM> and the electrode portion 25a become conducting, and in addition, when the switches 84a, <NUM> are controlled to be in the OFF state, a voltage is applied across the electrode portion 25a and the flexible electrode <NUM>. When the switch 83a is controlled to be in the OFF state, the power supply <NUM> and the electrode portion 25a become nonconducting, and the application of the voltage across the electrode portion 25a and the flexible electrode <NUM> is stopped. In the same manner, the application of the voltage across the electrode portion 25b and the flexible electrode <NUM> is controlled when the control unit <NUM> controls the ON/OFF state of each of the switches 83b, 84b, <NUM>.

Furthermore, the control unit <NUM> is adapted to control the output voltage of the power supply <NUM> so as to control the magnitude of a voltage to be applied across each of the electrode portions 25a, 25b and the flexible electrode <NUM>. This allows the control unit <NUM> to control the magnitude of the Coulomb force acting on the flexible electrode <NUM> and control the deformation amount of the flexible electrode <NUM>, thus controlling the displacement amount of the first output member <NUM>. When the power supply <NUM> is provided individually for the electrode portion 25a and the electrode portion 25b, for example, the control unit <NUM> may independently control the magnitude of the voltage to be applied across the electrode portion 25a and the flexible electrode <NUM> and the magnitude of the voltage to be applied across the electrode portion 25b and the flexible electrode <NUM>. This allows the control unit <NUM> to partially divide and control the deformation amount of the flexible electrode <NUM>, thus controlling the displacement amount of the first output member <NUM> in a complicated and fine manner.

<FIG> is a view explaining an aspect of deformation of the flexible electrode <NUM> when a voltage is applied across the electrode portion 25a, which is one of the electrode portions forming the first base electrode <NUM>, and the flexible electrode <NUM> illustrated in <FIG>.

As illustrated in <FIG>, when the switches 83a, 84b are controlled to be in the ON state and the switches 83b, 84a, <NUM> are controlled to be in the ON state, a voltage is applied only across the electrode portion 25a forming the first base electrode <NUM> and the flexible electrode <NUM> in the actuator <NUM>. In this case, the flexible electrode <NUM> coupled to the positive terminal of the power supply <NUM> is positively charged, and the electrode portion 25a coupled to the negative terminal of the power supply <NUM> is negatively charged. The first insulating layer 23a coating the inclined face 22a of the electrode portion 25a is polarized. The vicinity of the interface between the first insulating layer 23a and the electrode portion 25a is positively charged, and the vicinity of the surface opposite to the interface (on the first space <NUM> side) is negatively charged. A Coulomb force is generated between the first insulating layer 23a and the flexible electrode <NUM>. The Coulomb force causes the flexible electrode <NUM> to be attracted by the first insulating layer 23a. In the flexible electrode <NUM>, the portion of the first face <NUM> facing the first insulating layer 23a (in the -X-axis direction) deforms toward the first insulating layer 23a so as to adhere to the first insulating layer 23a. Since the first insulating layer 23a is inclined along the inclined face 22a, the first output member <NUM> coupled to the second face <NUM> of the flexible electrode <NUM> is displaced in the -Y-axis direction and the -X-axis direction. That is, the first base electrode <NUM> can cause the first output member <NUM> to rotate counterclockwise in the roll direction as viewed in the +Z-axis direction when a voltage is applied only across the electrode portion 25a and the flexible electrode <NUM>. It should be noted that when no electric charge is stored in the electrode portion 25b as in the startup of the actuator <NUM>, for example, the switch 84b in the example illustrated in <FIG> may be controlled to be in the OFF state.

<FIG> is a view explaining an aspect of deformation of the flexible electrode <NUM> when the application of the voltage is stopped after the state illustrated in <FIG>.

After the state illustrated in <FIG>, when the switches 83a, 83b are controlled to be in the OFF state, and the switches 84a, 84b, <NUM> are controlled to be in the ON state as illustrated in <FIG>, the application of a voltage across the electrode portion 25a, which is one of the electrode portions forming the first base electrode <NUM>, and the flexible electrode <NUM> is stopped. In this case, the electric charge stored in the electrode portion 25a and the flexible electrode <NUM>, to which a voltage has been applied, is released to the frame ground, for example. In the flexible electrode <NUM>, the portion of the first face <NUM> facing the first insulating layer 23a (in the -X-axis direction), adhering to the first insulating layer 23a, deforms so as to separate from the first insulating layer 23a and returns to the original shape. The first output member <NUM> coupled to the second face <NUM> of the flexible electrode <NUM> returns to the position in the initial state.

<FIG> is a view explaining an aspect of deformation of the flexible electrode <NUM> when a voltage is applied across the electrode portion 25b, which is the other one of the electrode portions forming the first base electrode <NUM>, and the flexible electrode <NUM> illustrated in <FIG>.

When the switches 83b, 84a are controlled to be in the ON state and the switches 83a, 84b, <NUM> are controlled to be in the OFF state as illustrated in <FIG>, a voltage is applied only across the electrode portion 25b forming the first base electrode <NUM> and the flexible electrode <NUM> in the actuator <NUM>. In this case, in the same manner as in <FIG>, in the flexible electrode <NUM>, the portion of the first face <NUM> facing the first insulating layer 23b (in the +X-axis direction) deforms toward the first insulating layer 23b so as to adhere to the first insulating layer 23b. Since the first insulating layer 23b is inclined along the inclined face 22b, the first output member <NUM> coupled to the second face <NUM> of the flexible electrode <NUM> is displaced in the -Y-axis direction and the +X-axis direction. That is, the first base electrode <NUM> can cause the first output member <NUM> to rotate clockwise in the roll direction as viewed in the +Z-axis direction when a voltage is applied only across the electrode portion 25b and the flexible electrode <NUM>. It should be noted that when no electric charge is stored in the electrode portion 25a as in the startup of the actuator <NUM>, for example, the switch 84a in the example illustrated in <FIG> may be controlled to be in the OFF state.

The control unit <NUM> can control the ON/OFF state of each of the switches 83a, 83b, 84a, 84b, <NUM> to be in the state of <FIG>, the state of <FIG>, and then the state of <FIG> in this order, or after the state of <FIG>, to be in the state of <FIG>, and then the state of <FIG> in this order. The state of the first base electrode <NUM> is alternately switched between the state where a voltage is applied only across the electrode portion 25a and the flexible electrode <NUM> and the state where a voltage is applied only across the electrode portion 25b and the flexible electrode <NUM>, with interposed therebetween, the state where the application of the voltage is stopped. The flexible electrode <NUM> is alternately switched between the aspect in which the flexible electrode <NUM> deforms toward the first insulating layer 23a illustrated in <FIG> and the aspect in which the flexible electrode <NUM> deforms toward the first insulating layer 23b illustrated in <FIG>, with interposed therebetween, the state where the flexible electrode <NUM> has returned to the original shape illustrated in <FIG>. That is, the deformation direction of the flexible electrode <NUM> may be alternately switched by the first base electrode <NUM> between the direction toward the first insulating layer 23a along the inclined face 22a and the direction toward the first insulating layer 23b along the inclined face 22b. Accordingly, the first base electrode <NUM> can cause the first output member <NUM> to swing in the direction rotating about the Z-axis.

<FIG> is a view explaining an aspect of deformation of the flexible electrode <NUM> when a voltage is applied across both of the electrode portions 25a, 25b forming the first base electrode <NUM> and the flexible electrode <NUM> illustrated in <FIG>.

When both of the switch 83a and the switch 83b are controlled to be in the ON state and the switches 84a, 84b, <NUM> are controlled to be in the OFF state as illustrated in <FIG>, a voltage is applied across the electrode portion 25a of the first base electrode <NUM> and the flexible electrode <NUM> as well as across the electrode portion 25b of the first base electrode <NUM> and the flexible electrode <NUM> in the actuator <NUM>. At this time, a voltage applied across the electrode portion 25a and the flexible electrode <NUM> is equal to that applied across the electrode portion 25b and the flexible electrode <NUM>. In this case, in the flexible electrode <NUM>, approximately all of the portions of the first face <NUM> deform toward the first insulating layers 23a, 23b so as to adhere to the first insulating layers 23a, 23b. Since the first insulating layers 23a, 23b are inclined along the inclined faces 22a, 22b, the first output member <NUM> coupled to the second face <NUM> of the flexible electrode <NUM> is displaced in the -Y-axis direction. That is, the first base electrode <NUM> can cause the first output member <NUM> to translationally move along the Y-axis when a voltage is applied across the electrode portion 25a and the flexible electrode <NUM> as well as across the electrode portion 25b and the flexible electrode <NUM>.

The drive circuit <NUM> adapted to apply a voltage across the second base electrode <NUM> and the flexible electrode <NUM> can also independently control a voltage to be applied across each of the electrode portions 35a, 35b forming the second base electrode <NUM> and the flexible electrode <NUM> in the same manner as those illustrated in <FIG>. With such a configuration, the second base electrode <NUM> can cause the second output member <NUM> to rotate counterclockwise or clockwise in the yaw direction as viewed in the +Y-axis direction, and to swing in the direction rotating about the Y-axis. Further, the second base electrode <NUM> can cause the second output member <NUM> to translationally move along the X-axis.

The drive circuit <NUM> adapted to apply a voltage across the third base electrode <NUM> and the flexible electrode <NUM> can also independently control a voltage to be applied across each of the electrode portions 45a, 45b forming the third base electrode <NUM> and the flexible electrode <NUM> in the same manner as those illustrated in <FIG>. With such a configuration, the third base electrode <NUM> can cause the third output member <NUM> to rotate counterclockwise or clockwise in the pitch direction as viewed in the +X-axis direction, and to swing in the direction rotating about the X-axis. Further, the third base electrode <NUM> can cause the third output member <NUM> to translationally move along the Z-axis.

<FIG> is a view explaining a principle of detection of a displacement amount of the output members <NUM> to <NUM>. It should be noted that <FIG> corresponds to <FIG>.

In the actuator <NUM>, since the output members <NUM> to <NUM> are driven in a state of being coupled to the external device, while driven, the flexible electrode <NUM> receives an external force F due to the coupling to the external device, and thus is prevented from deforming to adhere to the base electrodes <NUM> to <NUM>. Meanwhile, it is known that there is a predetermined negative correlation between the distance between the base electrodes <NUM> to <NUM> and the flexible electrode <NUM> and the amount of electric charge stored between the base electrodes <NUM> to <NUM> and the flexible electrode <NUM>.

The control unit <NUM> of the drive circuit <NUM> can store in advance, as a reference amount of electric charge, the amount of electric charge stored in a state where the output members <NUM> to <NUM> are not coupled to the external device and the flexible electrode <NUM> is adhering to the base electrodes <NUM> to <NUM>. The control unit <NUM> can calculate a distance between the flexible electrode <NUM> that has received the external force F and the base electrodes <NUM> to <NUM> by comparing the amount of electric charge stored while the actuator <NUM> is driven and the reference amount of electric charge. From the result of the calculated distance, the control unit <NUM> can calculate the deformation amount of the flexible electrode <NUM>. From the deformation amount of the flexible electrode <NUM>, the control unit <NUM> can not only calculate the displacement amount of the output members <NUM> to <NUM>, but also calculate the magnitude of the external force F acting on the flexible electrode <NUM>.

As described above, in the actuator <NUM>, the control unit <NUM> of the drive circuit <NUM> can detect a displacement amount of each of the output members <NUM> to <NUM> by detecting an amount of electric charge stored in the flexible electrode <NUM>. The actuator <NUM> can detect a displacement amount of each the output members <NUM> to <NUM> without newly introducing a detection device separate from the actuator <NUM> such as a laser displacement gage. By controlling the output voltage of the power supply <NUM> to match the detected displacement amount with a target displacement amount, the control unit <NUM> can perform feedback control of the displacement amount of the output members <NUM> to <NUM>. Therefore, the actuator <NUM> can control the movement with multiple degrees of freedom with a simple configuration.

It should be noted that in the above descriptions, the actuator <NUM> includes the base electrodes <NUM> to <NUM> disposed to face the flexible electrode <NUM> on the three axes: X-axis, Y-axis, and Z-axis. However, the actuator <NUM> of the first embodiment is not limited to this, and may include base electrodes disposed to face the flexible electrode <NUM> at least on two axes that cross each other. For example, the actuator <NUM> of the first embodiment may include only the first base electrode <NUM> on the Y-axis and the second base electrode <NUM> on the X-axis. In addition, as long as the flexible electrode <NUM> is formed into a three-dimensional shape, the shape of the flexible electrode <NUM> may be other than a hexahedron. Further, the flexible electrode <NUM> may include a portion which will not deform according to the above-mentioned Coulomb force, and such a portion may be restricted by being fixed to an external member.

<FIG> is a table showing the results of simulation analysis performed for the operation of the actuator <NUM> illustrated in <FIG>. <FIG> is a view showing the analysis result of an aspect of deformation of the flexible electrode <NUM> in a first state illustrated in <FIG>. <FIG> is a view showing the analysis result of an aspect of deformation of the flexible electrode <NUM> in a second state illustrated in <FIG>. <FIG> is a view showing the analysis result of an aspect of deformation of the flexible electrode <NUM> in a third state illustrated in <FIG>. <FIG> is a view showing the analysis result of an aspect of deformation of the flexible electrode <NUM> in an eighth state illustrated in <FIG>. It should be noted that in <FIG>, a portion having a high level of gray scale in the flexible electrode <NUM> indicates that the portion has a large deformation amount (i.e., displacement amount) with reference to the initial state, and a portion having a low level of gray scale in the flexible electrode <NUM> indicates that the portion has a small deformation amount (i.e., displacement amount) with reference to the initial state.

The analysis used a model in which the third base electrode <NUM> and the third output member <NUM> are omitted from the actuator <NUM> illustrated in <FIG> and <FIG>. As analysis conditions, the output end <NUM> and the beam portion <NUM> of the first output member <NUM> each had a Young's modulus of <NUM> GPa. In the horizontal portion <NUM> of the coupling portion <NUM> of the first output member <NUM>, displacement of the horizontal portion <NUM> in the axial direction was allowed, whereas displacement and rotation of the horizontal portion <NUM> in a direction other than the axial direction were restricted. In the vertical portion <NUM> of the coupling portion <NUM> of the first output member <NUM>, relative displacement between the node <NUM> and the node <NUM> located on the opposite ends of the vertical portion <NUM> was restricted, rotation of the node <NUM> was allowed, and rotation of the node <NUM> was restricted. The magnitude of a voltage to be applied across one of the plurality of electrode portions 25a, 25b forming the first base electrode <NUM> and the flexible electrode <NUM> was equal to the magnitude of a voltage to be applied across the other one of the plurality of electrode portions 25a, 25b forming the first base electrode <NUM> and the flexible electrode <NUM>. The same analysis conditions were employed for the second output member <NUM>.

Then, a displacement amount of each of the first output member <NUM> and the second output member <NUM> in the first state to the eighth state illustrated in <FIG> was obtained, in which the application of a voltage across each of the plurality of electrode portions 25a, 25b and the flexible electrode <NUM> and the application of a voltage across each of the plurality of electrode portions 35a, 35b and the flexible electrode <NUM> were changed from the initial state. In the initial state, a voltage is not applied across each of the plurality of electrode portions 25a, 25b and the flexible electrode <NUM> or across each of the plurality of electrode portions 35a, 35b and the flexible electrode <NUM>.

In the item "Voltage application" in <FIG>, the sign "o" shows that a voltage is applied, and the sign "×" shows that a voltage is not applied. In the item "Displacement amount" in <FIG>, the items "X", "Y" and "Z" of "First output member <NUM>" show how much the output end <NUM> of the first output member <NUM> is displaced along the X-axis, the Y-axis, and the Z-axis from the initial state, respectively. The items "X", "Y" and "Z" of "Second output member <NUM>" show how much the output end <NUM> of the second output member <NUM> is displaced along the X-axis, the Y-axis, and the Z-axis from the initial state, respectively. In the item "Displacement amount," a positive displacement amount shows that the output member is displaced in the plus direction of each axis, and a negative displacement amount shows that the output member is displaced in the minus direction of each axis.

As illustrated in <FIG>, the first state shows that a voltage is applied only across the electrode portion 25a and the flexible electrode <NUM>. In this case, the output end <NUM> of the first output member <NUM> is displaced by <NUM> in the -X-axis direction and by <NUM> in the -Y-axis direction from the initial state, and is not displaced in the ±Z-axis directions. The output end <NUM> of the second output member <NUM> is displaced in none of the ±X-axis directions, ±Y-axis directions, and ±Z-axis directions from the initial state. <FIG> illustrates an aspect of deformation of the flexible electrode <NUM> in the first state. In view of these analysis results, it is found that the actuator <NUM> can cause the first output member <NUM> to rotate counterclockwise in the roll direction as viewed in the +Z-axis direction when a voltage is applied only across the electrode portion 25a and the flexible electrode <NUM>, as explained with reference to <FIG>.

As illustrated in <FIG>, the second state shows that a voltage is applied only across the electrode portion 25b and the flexible electrode <NUM>. In this case, the output end <NUM> of the first output member <NUM> is displaced by <NUM> in the +X-axis direction and by <NUM> in the -Y-axis direction from the initial state, and is not displaced in the ±Z-axis directions. The output end <NUM> of the second output member <NUM> is displaced by <NUM> in the -Y-axis direction from the initial state and is not displaced in the ±X-axis directions or ±Z-axis directions. <FIG> illustrates an aspect of deformation of the flexible electrode <NUM> in the second state. In view of these analysis results, it is found that the actuator <NUM> can cause the first output member <NUM> to rotate clockwise in the roll direction as viewed in the +Z-axis direction when a voltage is applied only across the electrode portion 25b and the flexible electrode <NUM>, as explained with reference to <FIG>.

As illustrated in <FIG>, the third state shows that a voltage is applied across each of the electrode portions 25a, 25b and the flexible electrode <NUM> and a voltage is not applied across each of the electrode portions 35a, 35b and the flexible electrode <NUM>. In this case, the output end <NUM> of the first output member <NUM> is displaced by <NUM> in the -Y-axis direction from the initial state, and is not displaced in the ±X-axis directions or ±Z-axis directions. The output end <NUM> of the second output member <NUM> is displaced by <NUM> in the -Y-axis direction from the initial state, and is not displaced in the ±X-axis directions or ±Z-axis directions. <FIG> illustrates an aspect of deformation of the flexible electrode <NUM> in the third state. In view of these analysis results, it is found that the actuator <NUM> can cause the first output member <NUM> to translationally move along the Y-axis when a voltage is applied across each of the electrode portions 25a, 25b and the flexible electrode <NUM>, as explained with reference to <FIG>.

As illustrated in <FIG>, the eighth state shows that a voltage is applied across each of the electrode portions 25a, 25b and the flexible electrode <NUM> and across each of the electrode portions 35a, 35b and the flexible electrode <NUM>. In this case, the output end <NUM> of the first output member <NUM> is displaced by <NUM> in the -X-axis direction and by <NUM> in the -Y-axis direction from the initial state, and is not displaced in the ±Z-axis directions. The output end <NUM> of the second output member <NUM> is displaced by <NUM> in the -X-axis direction and by <NUM> in the -Y-axis direction from the initial state, and is not displaced in the ±Z-axis directions. <FIG> illustrates an aspect of deformation of the flexible electrode <NUM> in the eighth state. In view of these analysis results, it is found that the actuator <NUM> can cause the first output member <NUM> and the second output member <NUM> to be displaced along the X-axis and the Y-axis, respectively, when a voltage is applied across each of the electrode portions 25a, 25b and the flexible electrode <NUM> and across each of the electrode portions 35a, 35b and the flexible electrode <NUM>, and can achieve complicated movement with multiple degrees of freedom.

As described above, the actuator <NUM> of the first embodiment includes the flexible electrode <NUM>, which has flexibility, and the first base electrode <NUM>, which is disposed to face the flexible electrode <NUM> on the Y-axis and is provided with the first insulating layers 23a, 23b on the opposite face <NUM> facing the flexible electrode <NUM>. The actuator <NUM> includes the second base electrode <NUM>, which is disposed to face the flexible electrode <NUM> on the X-axis crossing the Y-axis and is provided with the second insulating layers 33a, 33b on the opposite face <NUM> facing the flexible electrode <NUM>. The actuator <NUM> includes the first output member <NUM> and the second output member <NUM>, which are displaced according to the deformation of the flexible electrode <NUM> and are adapted to output work to the outside. In the actuator <NUM>, the first space <NUM> is formed between the first insulating layers 23a, 23b and the flexible electrode <NUM>, in which the flexible electrode <NUM> deforms toward the first insulating layers 23a, 23b by the voltage applied across the first base electrode <NUM> and the flexible electrode <NUM>. In the actuator <NUM>, the second space <NUM> is formed between the second insulating layers 33a, 33b and the flexible electrode <NUM>, in which the flexible electrode <NUM> deforms toward the second insulating layers 33a, 33b by the voltage applied across the second base electrode <NUM> and the flexible electrode <NUM>.

With such a configuration, the actuator <NUM> of the first embodiment can cause dielectric polarization of the first insulating layers 23a, 23b provided in the first base electrode <NUM> by the voltage applied across the first base electrode <NUM> and the flexible electrode <NUM> and generate a Coulomb force between the first insulating layers 23a, 23b and the flexible electrode <NUM>. The actuator <NUM> can cause the flexible electrode <NUM> to deform along the Y-axis by using the effect of the Coulomb force generated between the first insulating layers 23a, 23b and the flexible electrode <NUM>. In the same manner, the actuator <NUM> can cause dielectric polarization of the second insulating layers 33a, 33b provided in the second base electrode <NUM> by the voltage applied across the second base electrode <NUM> and the flexible electrode <NUM> and generate a Coulomb force between the second insulating layers 33a, 33b and the flexible electrode <NUM>. The actuator <NUM> can cause the flexible electrode <NUM> to deform along the X-axis by using the effect of the Coulomb force generated between the second insulating layers 33a, 33b and the flexible electrode <NUM>. The actuator <NUM> can cause the first output member <NUM> and the second output member <NUM> to be displaced along the X-axis and the Y-axis, respectively, according to the deformation of the flexible electrode <NUM> along the X-axis and the Y-axis, respectively. Therefore, with only one actuator <NUM> provided with one flexible electrode <NUM>, the actuator <NUM> of the first embodiment can easily achieve movement with multiple degrees of freedom, even without combining two or more actuators.

In addition, the actuator <NUM> of the first embodiment can detect a deformation amount of the flexible electrode <NUM> and a displacement amount of each of the first output member <NUM> and the second output member <NUM> by detecting an amount of electric charge stored in the flexible electrode <NUM> through an existing method. That is, the actuator <NUM> can detect a displacement amount of each of the first output member <NUM> and the second output member <NUM> without newly introducing a detection device separate from the actuator <NUM>. Therefore, the actuator <NUM> of the first embodiment can control the movement with multiple degrees of freedom with a simple configuration.

Furthermore, the first base electrode <NUM> is formed of the plurality of electrode portions 25a, 25b adapted to independently receive a voltage, and the second base electrode <NUM> is formed of the plurality of electrode portions 35a, 35b adapted to independently receive a voltage.

With such a configuration, the first base electrode <NUM> can control the voltage applied across the first base electrode <NUM> and the flexible electrode <NUM> for each of the plurality of electrode portions 25a, 25b. The first base electrode <NUM> can control the Coulomb force acting on the flexible electrode <NUM> for each of the plurality of electrode portions 25a, 25b. Accordingly, the first base electrode <NUM> can cause the flexible electrode <NUM> to deform in a more complicated and fine manner as compared to the first base electrode <NUM> not including the plurality of electrode portions 25a, 25b, thus allowing the first output member <NUM> to be displaced in a complicated and fine manner. Likewise, also when the second base electrode <NUM> is formed of the plurality of electrode portions 35a, 35b as described above, the second base electrode <NUM> can cause the second output member <NUM> to be displaced in a complicated and fine manner. Therefore, the actuator <NUM> of the first embodiment can easily achieve complicated and fine movement with multiple degrees of freedom.

Furthermore, the plurality of electrode portions 25a, 25b respectively has the inclined faces 22a, 22b that face the flexible electrode <NUM> and are inclined with respect to the flexible electrode <NUM>. The plurality of electrode portions 35a, 35b respectively has the inclined faces 32a, 32b that face the flexible electrode <NUM> and are inclined with respect to the flexible electrode <NUM>. The inclined faces 22a, 22b of the plurality of electrode portions 25a, 25b are inclined in the directions different from each other, and the inclined faces 32a, 32b of the plurality of electrode portions 35a, 35b are inclined in the directions different from each other.

With such a configuration, the first base electrode <NUM> can cause the flexible electrode <NUM> to deform toward each of the plurality of inclined faces 22a, 22b that are inclined in the directions different from each other with respect to the flexible electrode <NUM>. Accordingly, the first base electrode <NUM> can cause the first output member <NUM> to be displaced so as to rotate in the direction crossing the Y-axis. In particular, by alternately applying a voltage and stopping application of the voltage between the electrode portion 25a and the electrode portion 25b, which are one and the other one of the plurality of electrode portions 25a, 25b, the first base electrode <NUM> can switch the deformation direction of the flexible electrode <NUM> between the direction toward the inclined face 22a of the one electrode portion 25a and the direction toward the inclined face 22b of the other electrode portion 25b alternately. Accordingly, the first base electrode <NUM> can cause the first output member <NUM> to be displaced so as to swing in the direction crossing the Y-axis. Likewise, also when the plurality of electrode portions 35a, 35b forming the second base electrode <NUM> respectively has the inclined faces 32a, 32b as described above, the second base electrode <NUM> can cause the second output member <NUM> to be displaced so as to rotate or swing in the direction crossing the X-axis. Therefore, the actuator <NUM> of the first embodiment can easily achieve various types of movement, in addition to the transitional movement along the X-axis or the Y-axis.

Furthermore, the flexible electrode <NUM> is formed into a hexahedron, which has the first face <NUM> crossing the Y-axis, the second face <NUM> facing the first face <NUM> on the Y-axis, the third face <NUM> crossing the X-axis, and the fourth face <NUM> facing the third face <NUM> on the X-axis. In the first base electrode <NUM>, the opposite face <NUM> facing the flexible electrode <NUM> faces the first face <NUM> of the flexible electrode <NUM>, and the first space <NUM> is formed between the first insulating layers 23a, 23b provided on the opposite face <NUM> of the first base electrode <NUM> facing the flexible electrode <NUM> and the first face <NUM>. In the second base electrode <NUM>, the opposite face <NUM> facing the flexible electrode <NUM> faces the third face <NUM> of the flexible electrode <NUM>, and the second space <NUM> is formed between the second insulating layers 33a, 33b provided on the opposite face <NUM> of the second base electrode <NUM> facing the flexible electrode <NUM> and the third face <NUM>. The actuator <NUM> of the first embodiment includes the first output member <NUM> attached to the second face <NUM> and the second output member <NUM> attached to the fourth face <NUM>.

With such a configuration, the actuator <NUM> of the first embodiment can cause the first output member <NUM> and the second output member <NUM> to be displaced along the Y-axis and the X-axis, respectively, even with a simple structure including the flexible electrode <NUM>, the first base electrode <NUM>, and the second base electrode <NUM>. Therefore, the actuator <NUM> of the first embodiment can more easily achieve movement with multiple degrees of freedom.

Furthermore, the actuator <NUM> of the first embodiment further includes the third base electrode <NUM> disposed to face the flexible electrode <NUM> on the Z-axis and is provided with the third insulating layers 43a, 43b on the opposite face <NUM> facing the flexible electrode <NUM>. In actuator <NUM>, the third space <NUM> is formed between the third insulating layers 43a, 43b and the flexible electrode <NUM>, in which the flexible electrode <NUM> deforms toward the third insulating layers 43a, 43b by the voltage applied across the third base electrode <NUM> and the flexible electrode <NUM>.

With such a configuration, the actuator <NUM> of the first embodiment can cause the flexible electrode <NUM> to deform along the Z-axis in addition to the X-axis and the Y-axis. The actuator <NUM> can cause the third output member <NUM> to be displaced along the Z-axis. Therefore, the actuator <NUM> of the first embodiment can easily achieve movement with greater degrees of freedom.

With reference to <FIG>, an actuator <NUM> of each of the second to fifth embodiments will be described. In the descriptions of the second to fifth embodiments, descriptions of the configuration and operation equal to those of the first embodiment will be omitted.

<FIG> is a schematic view of an actuator <NUM> of the second embodiment. It should be noted that <FIG> corresponds to <FIG>.

The actuator <NUM> of the second embodiment further includes a movable base electrode <NUM>, which is different from the actuator <NUM> of the first embodiment. The movable base electrode <NUM> is an electrode that is disposed opposite to the first base electrode <NUM> with at least a portion of the flexible electrode <NUM> interposed therebetween on the Y-axis, and is adapted to be movable along the Y-axis with respect to the first base electrode <NUM>.

The movable base electrode <NUM> includes an opposite face <NUM> facing the flexible electrode <NUM> in the same manner as the first base electrode <NUM>. In the present embodiment, the opposite face <NUM> facing the flexible electrode <NUM> faces the second face <NUM> of the flexible electrode <NUM>. The opposite face <NUM> facing the flexible electrode <NUM> is formed into a shape to fit into the opposite face <NUM> of the first base electrode <NUM> facing the flexible electrode <NUM>. The opposite face <NUM> facing the flexible electrode <NUM> is provided with insulating layers 231a, 231b. In the same manner as the first insulating layers 23a, 23b, the insulating layers 231a, 231b are formed by using a ferroelectric material including ceramics. A space <NUM> is formed between the insulating layers 231a, 231b and the flexible electrode <NUM>, in which the movable base electrode <NUM> moves by the voltage applied across the movable base electrode <NUM> and the flexible electrode <NUM>. In the present embodiment, the space <NUM> is formed between the insulating layers 231a, 231b provided on the opposite face <NUM> of the movable base electrode <NUM> facing the flexible electrode <NUM> and the second face <NUM> of the flexible electrode <NUM>.

In the same manner as the first base electrode <NUM>, the movable base electrode <NUM> may be formed of a plurality of electrode portions 251a, 251b. The plurality of electrode portions 251a, 251b is insulated from each other by a plate-like insulating portion <NUM> and each of the plurality of electrode portions 251a, 251b may independently receive a voltage applied across the movable base electrode <NUM> and the flexible electrode <NUM>. In the same manner as the plurality of electrode portions 25a, 25b forming the first base electrode <NUM>, the plurality of electrode portions 251a, 251b respectively has inclined faces 221a, 221b that face the flexible electrode <NUM> and are inclined with respect to the flexible electrode <NUM>. The inclined faces 221a, 221b are inclined with respect to the second face <NUM>. The inclined face 221a and the inclined face 221b are inclined in the directions different from each other. The inclined face 221a is formed into a shape to fit into the inclined face 22a of the first base electrode <NUM>. The inclined face 221b is formed into a shape to fit into the inclined face 22b of the first base electrode <NUM>. The opposite face <NUM> formed of the inclined faces 221a, 221b facing the flexible electrode <NUM> is recessed in the +Y-axis direction and is formed into a valley shape having a ridge along the Z-axis.

The first output member <NUM> of the second embodiment may be attached to a face <NUM> of the movable base electrode <NUM>. The face <NUM> of the movable base electrode <NUM> is a face positioned opposite to the opposite face <NUM> of the movable base electrode <NUM> in the direction along the Y-axis. Alternatively, the first output member <NUM> of the second embodiment may be attached to the second face <NUM> of the flexible electrode <NUM>, not to the movable base electrode <NUM>.

In the drive circuit <NUM> of the second embodiment, the flexible electrode <NUM> is coupled to one of the positive terminal and the negative terminal of the power supply <NUM>. The first base electrode <NUM> and the movable base electrode <NUM> are coupled in parallel to the other one of the positive terminal and the negative terminal of the power supply <NUM>. The electrode portion 25a and the electrode portion 25b forming the first base electrode <NUM> are coupled to each other in parallel to the other one of the positive terminal and the negative terminal of the power supply <NUM>. The electrode portion 251a and the electrode portion 251b forming the movable base electrode <NUM> are coupled to each other in parallel to the other one of the positive terminal and the negative terminal of the power supply <NUM>. The drive circuit <NUM> of the second embodiment further includes switches 83c, 83d, 84c, 84d, which is different from the drive circuit <NUM> of the first embodiment. The switch 83c is coupled between the electrode portion 251a and the power supply <NUM>. The switch 83d is coupled between the electrode portion 251b and the power supply <NUM>. The switch 84c is coupled between the electrode portion 251a and the frame ground (or earth). The switch 84d is coupled between the electrode portion 251b and the frame ground (or earth). The control unit <NUM> controls the ON/OFF state of the switches 83c, 83d, 84c, 84d independently.

In the actuator <NUM> of the second embodiment, when both of the switch 83a and the switch 83b are controlled to be in the ON state and the switches 84a, 84b, <NUM> are controlled to be in the OFF state, in the flexible electrode <NUM>, the first face <NUM> deforms toward the first insulating layers 23a, 23b so as to adhere to the first insulating layers 23a, 23b. As a result, the second face <NUM> of the flexible electrode <NUM> deforms into a shape along the inclined faces 22a, 22b coated with the first insulating layers 23a, 23b (see <FIG>).

In addition, in the actuator <NUM> of the second embodiment, when both of the switch 83c and the switch 83d are controlled to be in the ON state and the switches 84c, 84d are controlled to be in the OFF state, a Coulomb force is generated between the insulating layers 231a, 231b of the movable base electrode <NUM> and the flexible electrode <NUM>. The direction of this Coulomb force is equal to the direction of the Coulomb force generated between the first insulating layers 23a, 23b of the first base electrode <NUM> and the flexible electrode <NUM>. That is, in the actuator <NUM> of the second embodiment, the Coulomb force that causes the flexible electrode <NUM> to deform along the Y-axis can be enhanced as compared to the first embodiment. Then, the movable base electrode <NUM> moves toward the flexible electrode <NUM> such that the insulating layers 231a, 231b adhere to the second face <NUM> that has deformed into the shape along the inclined faces 221a, 221b. The first output member <NUM> attached to the face <NUM> of the movable base electrode <NUM> is displaced in the -Y-axis direction. The actuator <NUM> of the second embodiment can cause the first output member <NUM> to transitionally move along the Y-axis.

As described above, the actuator <NUM> of the second embodiment further includes the movable base electrode <NUM> that is disposed opposite to the first base electrode <NUM> with at least a portion of the flexible electrode <NUM> interposed therebetween on the Y-axis, and is adapted to move along the Y-axis with respect to the first base electrode <NUM>. The movable base electrode <NUM> is formed into a shape to fit into the opposite face <NUM> of the first base electrode <NUM>, and the opposite face <NUM> facing the flexible electrode <NUM> is provided with the insulating layers 231a, 231b. The space <NUM> is formed between the insulating layers 231a, 231b of the movable base electrode <NUM> and the flexible electrode <NUM>, in which the movable base electrode <NUM> moves by the voltage applied across the movable base electrode <NUM> and the flexible electrode <NUM>.

With such a configuration, the actuator <NUM> of the second embodiment can cause the Coulomb force generated between the insulating layers 231a, 231b of the movable base electrode <NUM> and the flexible electrode <NUM> to act on the flexible electrode <NUM>. The direction of the Coulomb force generated between the insulating layers 231a, 231b of the movable base electrode <NUM> and the flexible electrode <NUM> is equal to the direction of the Coulomb force generated between the first insulating layers 23a, 23b of the first base electrode <NUM> and the flexible electrode <NUM>. That is, the actuator <NUM> of the second embodiment can enhance the Coulomb force that causes the flexible electrode <NUM> to deform along the Y-axis. Since the actuator <NUM> of the second embodiment can enhance the power to cause the first output member <NUM> to be displaced along the Y-axis, it can have a higher output in the direction along the Y-axis. Therefore, the actuator <NUM> of the second embodiment can easily achieve movement with multiple degrees of freedom and can also increase an output.

Further, in the actuator <NUM> of the second embodiment, the opposite face <NUM> (i.e., the inclined faces 221a, 221b) of the movable base electrode <NUM> is formed into a shape to fit into the opposite face <NUM> (i.e., the inclined faces 22a, 22b) of the first base electrode <NUM>. With this configuration, the actuator <NUM> of the second embodiment can further enhance the Coulomb force generated between the insulating layers 231a, 231b of the movable base electrode <NUM> and the flexible electrode <NUM>. Since the actuator <NUM> of the second embodiment can further enhance the power to cause the first output member <NUM> to be displaced along the Y-axis, it can have an even higher output in the direction along the Y-axis. Therefore, the actuator <NUM> of the second embodiment can easily achieve movement with multiple degrees of freedom and can further increase an output.

It should be noted that in the above descriptions, the actuator <NUM> of the second embodiment includes the movable base electrode <NUM> that is disposed opposite to the first base electrode <NUM> with at least a portion of the flexible electrode <NUM> interposed therebetween on the Y-axis. However, the actuator <NUM> of the second embodiment is not limited to this, and may further include a movable base electrode that is disposed opposite to the second base electrode <NUM> with at least a portion of the flexible electrode <NUM> interposed therebetween on the X-axis. In addition, the actuator <NUM> of the second embodiment may further include a movable base electrode that is disposed opposite to the third base electrode <NUM> with at least a portion of the flexible electrode <NUM> interposed therebetween on the Z-axis.

<FIG> is a schematic view of an actuator <NUM> of the third embodiment. It should be noted that <FIG> corresponds to <FIG>. The illustration of the control unit <NUM> is omitted in <FIG>.

The actuator <NUM> of the third embodiment has an inner space <NUM> in the flexible electrode <NUM>. That is, the flexible electrode <NUM> of the third embodiment has a hollow structure. With this configuration, the flexible electrode <NUM> of the third embodiment can deform more easily as compared to the flexible electrode <NUM> with a solid structure. Accordingly, the actuator <NUM> of the third embodiment can cause the flexible electrode <NUM> to deform even if a voltage applied to the flexible electrode <NUM> is reduced. This can reduce power consumption and easily ensure insulation, and thus can increase safety. In addition, the actuator <NUM> of the third embodiment can reduce its weight and cost as compared to the one in which the flexible electrode <NUM> has a solid structure. Therefore, the actuator <NUM> of the third embodiment can achieve movement with multiple degrees of freedom even more easily and safely.

<FIG> is a schematic view of an actuator <NUM> of the fourth embodiment. It should be noted that <FIG> corresponds to <FIG>. The illustration of the control unit <NUM> is omitted in <FIG>.

The actuator <NUM> of the fourth embodiment includes the inner space <NUM> in the flexible electrode <NUM> as in the third embodiment. The actuator <NUM> of the fourth embodiment includes the movable base electrode <NUM> as in the second embodiment. Furthermore, the actuator <NUM> of the fourth embodiment includes the movable base electrode <NUM> disposed in the inner space <NUM>. With this configuration, the actuator <NUM> of the fourth embodiment can reduce its size as compared to the one in which the movable base electrode <NUM> is disposed outside of the flexible electrode <NUM>. Therefore, the actuator <NUM> of the fourth embodiment can easily achieve movement with multiple degrees of freedom and can achieve downsizing. It should be noted that in the drive circuit <NUM> of the fourth embodiment, the switches 83c, 83d may be disposed in the inner space <NUM> of the flexible electrode <NUM> as illustrated in <FIG>, or may be disposed outside of the flexible electrode <NUM>.

<FIG> is a schematic view of an actuator <NUM> of the fifth embodiment. <FIG> is a schematic view of the first base electrode <NUM> illustrated in <FIG>. <FIG> is a schematic view of another example of the first base electrode <NUM> illustrated in <FIG>. It should be noted that <FIG> corresponds to <FIG>. The illustration of the first insulating layer <NUM> is omitted in <FIG> and <FIG>.

In the actuator <NUM> of the fifth embodiment, the base electrodes <NUM> to <NUM> each are formed into a dome shape, such as a hemisphere. The first base electrode <NUM> of the fifth embodiment is disposed such that the top portion of the dome faces the first face <NUM> of the flexible electrode <NUM> and the central axis of the dome is along the Y-axis. The second base electrode <NUM> of the fifth embodiment is disposed such that the top portion of the dome faces the third face <NUM> of the flexible electrode <NUM> and the central axis of the dome is along the X-axis. The third base electrode <NUM> of the fifth embodiment is disposed such that the top portion of the dome faces the fifth face <NUM> of the flexible electrode <NUM> and the central axis of the dome is along the Z-axis.

The first base electrode <NUM> of the fifth embodiment includes the opposite face <NUM> facing the flexible electrode <NUM> as in the first embodiment. The opposite face <NUM> facing the flexible electrode <NUM> is provided with the first insulating layer <NUM>. The first insulating layer <NUM> is formed by using a ferroelectric material including ceramics as in the first embodiment. The first space <NUM> is formed between the first insulating layer <NUM> and the flexible electrode <NUM>, in which the flexible electrode <NUM> deforms toward the first insulating layer <NUM> by the voltage applied across the first base electrode <NUM> and the flexible electrode <NUM>.

In the same manner as the first base electrode <NUM> of the fifth embodiment, the second base electrode <NUM> of the fifth embodiment includes the opposite face <NUM> facing the flexible electrode <NUM>. The opposite face <NUM> facing the flexible electrode <NUM> is provided with the second insulating layer <NUM>. In the same manner as the first insulating layer <NUM>, the second insulating layer <NUM> is formed by using a ferroelectric material including ceramics. The second space <NUM> is formed between the second insulating layer <NUM> and the flexible electrode <NUM>, in which the flexible electrode <NUM> deforms toward the second insulating layer <NUM> by the voltage applied across the second base electrode <NUM> and the flexible electrode <NUM>.

In the same manner as the first base electrode <NUM> of the fifth embodiment, the third base electrode <NUM> of the fifth embodiment includes the opposite face <NUM> facing the flexible electrode <NUM>. The opposite face <NUM> facing the flexible electrode <NUM> is provided with the third insulating layer <NUM>. In the same manner as the first insulating layer <NUM>, the third insulating layer <NUM> is formed by using a ferroelectric material including ceramics. The third space <NUM> is formed between the third insulating layer <NUM> and the flexible electrode <NUM>, in which the flexible electrode <NUM> deforms toward the third insulating layer <NUM> by the voltage applied across the third base electrode <NUM> and the flexible electrode <NUM>.

Furthermore, as illustrated in <FIG>, the first base electrode <NUM> of the fifth embodiment may be formed of a plurality of electrode portions 25c to 25f as in the first embodiment. The plurality of electrode portions 25c to 25f is insulated from each other by the plate-like insulating portion <NUM> and each of the plurality of electrode portions 25c to 25f may independently receive a voltage applied across the first base electrode <NUM> and the flexible electrode <NUM>. As in the first embodiment, the plurality of electrode portions 25c to 25f respectively has inclined faces 22c to 22f that face the flexible electrode <NUM> and are inclined with respect to the flexible electrode <NUM>. The inclined faces 22c to 22f are inclined in the directions different from each other. The plurality of electrode portions 25c to 25f is disposed along the direction rotating about the Y-axis (yaw direction). The plurality of electrode portions 25c to 25f may be formed by dividing the hemispherical first base electrode <NUM> at regular intervals in the direction rotating about the Y-axis.

In the same manner as the first base electrode <NUM> of the fifth embodiment, the second base electrode <NUM> of the fifth embodiment may be formed of a plurality of electrode portions, which is insulated from each other and is adapted to independently receive a voltage applied across the second base electrode <NUM> and the flexible electrode <NUM>. In the same manner as the plurality of electrode portions 25c to 25f, the plurality of electrode portions forming the second base electrode <NUM> of the fifth embodiment respectively has inclined faces that face the flexible electrode <NUM> and are inclined with respect to the flexible electrode <NUM>. The plurality of electrode portions forming the second base electrode <NUM> of the fifth embodiment is disposed along the direction rotating about the X-axis (pitch direction).

In the same manner as the first base electrode <NUM> of the fifth embodiment, the third base electrode <NUM> of the fifth embodiment may be formed of a plurality of electrode portions, which is insulated from each other and is adapted to independently receive a voltage applied across the third base electrode <NUM> and the flexible electrode <NUM>. In the same manner as the plurality of electrode portions 25c to 25f, the plurality of electrode portions forming the third base electrode <NUM> of the fifth embodiment respectively has inclined faces that face the flexible electrode <NUM> and are inclined with respect to the flexible electrode <NUM>. The plurality of electrode portions forming the third base electrode <NUM> of the fifth embodiment is disposed along the direction rotating about the Z-axis (roll direction).

As described above, in the actuator <NUM> of the fifth embodiment, the plurality of electrode portions 25c to 25f forming the first base electrode <NUM> is disposed along the direction rotating about the Y-axis, and the plurality of electrode portions forming the second base electrode <NUM> is disposed along the direction rotating about the X-axis.

With such a configuration, the first base electrode <NUM> of the fifth embodiment can sequentially apply a voltage or sequentially stop application of the voltage across the first base electrode <NUM> and the flexible electrode <NUM> for each of the plurality of electrode portions 25c to 25f along the direction rotating about the Y-axis. The first base electrode <NUM> of the fifth embodiment can sequentially cause the flexible electrode <NUM> to deform toward each of the plurality of electrode portions 25c to 25f disposed along the direction rotating about the Y-axis. Accordingly, the first base electrode <NUM> of the fifth embodiment can cause the first output member <NUM> to be displaced to precess about the Y-axis as a rotation axis. Likewise, also when the second base electrode <NUM> is formed of a plurality of electrode portions as described above, the second base electrode <NUM> can cause the second output member <NUM> to be displaced to precess about the X-axis as a rotation axis. Therefore, the actuator <NUM> of the fifth embodiment can easily achieve various types of movement, in addition to the transitional movement along the X-axis or the Y-axis.

It should be noted that by equally applying a voltage, which is applied across the first base electrode <NUM> and the flexible electrode <NUM>, to all of the plurality of electrode portions 25c to 25f, the first base electrode <NUM> of the fifth embodiment can cause the first output member <NUM> to transitionally move along the Y-axis. By applying a voltage, which is applied across the first base electrode <NUM> and the flexible electrode <NUM>, to one of the plurality of electrode portions 25c to 25f, the first base electrode <NUM> of the fifth embodiment can cause the first output member <NUM> to rotate in the direction (the direction crossing the Y-axis) toward the inclined face of the one electrode portion. By alternately applying a voltage, which is applied across the first base electrode <NUM> and the flexible electrode <NUM>, to one and another one of the plurality of electrode portions 25c to 25f, the first base electrode <NUM> of the fifth embodiment can cause the first output member <NUM> to swing in the direction crossing the Y-axis. That is, the actuator <NUM> of the fifth embodiment can cause the first output member <NUM> to not only transitionally move along the Y-axis but also to rotate or swing in the direction crossing the Y-axis. In the same manner as the first output member <NUM>, the actuator <NUM> of the fifth embodiment can cause the second output member <NUM> to not only transitionally move along the X-axis but also to rotate or swing in the direction crossing the X-axis. In the same manner as the first output member <NUM>, the actuator <NUM> of the fifth embodiment can cause the third output member <NUM> to not only transitionally move along the Z-axis but also to rotate or swing in the direction crossing the Z-axis.

The number of electrode portions forming the base electrodes <NUM> to <NUM> of the fifth embodiment is not particularly limited. For example, the first base electrode <NUM> of the fifth embodiment may be formed of a plurality of electrode portions <NUM> to 25n as illustrated in <FIG>. The plurality of electrode portions <NUM> to 25n is insulated from each other by the plate-like insulating portion <NUM> and each of the plurality of electrode portions <NUM> to 25n may independently receive a voltage applied across the first base electrode <NUM> and the flexible electrode <NUM>. As the number of electrode portions forming the base electrodes <NUM> to <NUM> increases, the flexible electrode <NUM> can deform in a more complicated and fine manner, thus allowing the output members <NUM> to <NUM> to be displaced in a complicated and fine manner.

Claim 1:
An actuator (<NUM>) comprising:
a flexible electrode (<NUM>) having flexibility;
a first base electrode (<NUM>) disposed to face the flexible electrode (<NUM>) on a first axis and provided with a first insulating layer (<NUM>) on an opposite face facing the flexible electrode (<NUM>);
a second base electrode (<NUM>) disposed to face the flexible electrode on a second axis provided with a second insulating layer (<NUM>) on an opposite face facing the flexible electrode; and
an output member adapted to be displaced according to deformation of the flexible electrode (<NUM>) and output work to an outside,
wherein:
a first space (<NUM>) is formed between the first insulating layer (<NUM>) and the flexible electrode (<NUM>), in which the flexible electrode (<NUM>) deforms toward the first insulating layer (<NUM>) by a voltage applied across the first base electrode (<NUM>) and the flexible electrode (<NUM>), and
a second space is formed between the second insulating layer (<NUM>) and the flexible electrode (<NUM>), in which the flexible electrode (<NUM>) deforms toward the second insulating layer (<NUM>) by a voltage applied across the second base electrode (<NUM>) and the flexible electrode (<NUM>)
characterised by the second axis crossing the first axis at an origin located at the centre of the flexible electrode (<NUM>).