JP5370971B2 - Soft actuator using liquid crystal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a soft actuator using a liquid crystal capable of moving an object even on a curved surface having irregularities. <P>SOLUTION: The soft actuator includes: a fixed sheet SP which is fixed; a moving sheet MP provided movable relative to the fixed sheet SP; a liquid crystal LC provided between an upper surface of the fixed sheet SP and a lower surface of the moving sheet MP opposed to the upper surface of the fixed sheet SP; and a liquid crystal molecule rotation unit for rotating liquid crystal molecules m of the liquid crystal LC in a plane intersecting the upper surface of the fixed sheet SP and/or the lower surface of the moving sheet MP, and the fixed sheet SP is formed by a member having flexibility. The upper surface of the fixed sheet SP can be a curved surface, and then the moving sheet MP moves with its lower surface maintained substantially in parallel with the upper surface of the fixed sheet SP while moving in the direction of a liquid crystal flow. Accordingly, the moving sheet MP can be moved along the upper surface of the fixed sheet SP, namely along the curved surface. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

The present invention relates to a soft actuator using liquid crystal. A liquid crystal refers to a state that has fluidity but is optically anisotropic, exhibits birefringence, has crystal-like properties, or exhibits such a state. When an electric field or magnetic field is applied to the liquid crystal, all liquid crystal molecules rotate in the same direction around the center of gravity, and the axial direction is oriented at an angle unique to the liquid crystal with respect to the direction of the electric field or magnetic field.
The present invention relates to a soft actuator using liquid crystal using liquid crystal flow utilizing the properties of such liquid crystal.

  Conventionally, liquid crystals have been used in information display devices such as liquid crystal displays because their optical properties change as liquid crystal molecules are aligned.

In recent years, a mechanism for moving an object using liquid crystal flow generated when liquid crystal molecules are aligned has been developed (for example, Patent Document 1).
Such a mechanism includes a fixed flat plate whose movement is fixed, a movable flat plate provided so as to be movable with respect to the fixed flat plate, a liquid crystal filled between the two and anchored to both flat plates, and the liquid crystal. Means for applying an electric field perpendicular to the flat plate. With such a configuration, liquid crystal molecules can be rotated by applying an electric field, and liquid crystal flow due to the rotation of the liquid crystal can be generated. Then, since the moving flat plate is provided so as to be movable with respect to the fixed flat plate, and the liquid crystal is anchored to both flat plates, the moving flat plate can be moved along with the liquid crystal flow.

  As described above, it is possible to move an object such as a flat plate using the flow of liquid crystal, but if the object can be moved along the curved surface along the curved surface, the object along the surface of various objects etc. Can be moved, and its application can be greatly expanded.

Japanese Patent No. 3586734

  In view of the above circumstances, an object of the present invention is to provide a soft actuator using a liquid crystal that can move an object even on a curved surface having irregularities.

The soft actuator using the liquid crystal of the first invention is an actuator for moving an object by liquid crystal flow, a fixed member fixed, a moving member provided to be movable relative to the fixed member, Liquid crystal provided between the fixed-side facing surface of the fixing member and the moving-side facing surface of the moving member facing the fixed-side facing surface of the fixing member, and liquid crystal molecules of the liquid crystal Liquid crystal molecule rotating means that rotates in a plane that intersects the fixed side facing surface and / or the moving side facing surface of the moving member, and the fixing member is formed of a flexible member. Features.
The soft actuator using the liquid crystal of the second invention is an actuator for moving an object by liquid crystal flow, a fixed member fixed, a moving member provided to be movable relative to the fixed member, Liquid crystal provided between the fixed-side facing surface of the fixing member and the moving-side facing surface of the moving member facing the fixed-side facing surface of the fixing member, and liquid crystal molecules of the liquid crystal Liquid crystal molecule rotating means that rotates in a plane that intersects the fixed side facing surface and / or the moving side facing surface of the moving member , and the moving member is formed of a flexible member. Features.
The soft actuator using the liquid crystal according to a third aspect of the present invention is the soft actuator according to the first or second aspect, wherein the fixing member and the moving member are both sheet-like members having flexibility, and the fixing member and the moving member And the liquid crystal sandwiched between the two, the object moving sheet comprising

According to the first aspect, since the fixing member is formed of a flexible member, the fixing member can have a curved surface on the fixed side. Then, if the liquid crystal molecules are rotated by the liquid crystal molecule rotating means within the plane that intersects the fixed side facing surface of the fixing member and / or the moving side facing surface of the moving member, the liquid crystal molecules rotate along the facing surface between the facing surfaces of both members. Liquid crystal flow occurs. Then, since the fixed-side facing surface of the fixed member is a curved surface, the moving member can be moved along the fixed-side facing surface of the fixed member, that is, along the curved surface.
According to the second invention, if the liquid crystal molecules are rotated by the liquid crystal molecule rotating means in the plane intersecting the fixed side facing surface of the fixing member and / or the moving side facing surface of the moving member, between the facing surfaces of both members, Liquid crystal flow along the facing surface occurs. Since the moving member is formed of a flexible member, the moving member can be moved in the direction of liquid crystal flow while being deformed.
According to the third invention, since the fixed member and the moving member are both flexible in the object moving sheet, the object moving sheet can be an object having a curved surface or an object whose surface shape changes. Can be attached to the surface. Then, since the moving member has flexibility, the moving member can be moved along the surface of the object regardless of the surface shape of the object.

It is a schematic explanatory drawing of the soft actuator using the liquid crystal of this invention, (A) is a schematic sectional drawing, (B) is a schematic expanded sectional view. It is explanatory drawing of a motion of the liquid crystal molecule m when an electric field is applied to the liquid crystal LC mounted on the parallel plate P.

Next, an embodiment of the present invention will be described with reference to the drawings.
First, the principle of moving an object by the soft actuator using the liquid crystal of the present invention will be described.
In addition, when an electric field or a magnetic field is applied to the liquid crystal, the axial direction of the liquid crystal molecules is aligned at an angle unique to the liquid crystal with respect to the direction of the electric field or the magnetic field. A liquid crystal in which the axial direction of liquid crystal molecules is parallel to the direction of an electric field or magnetic field will be described.
In addition, since the liquid crystal molecules are aligned when an electric field or a magnetic field is applied, only the case where an electric field is applied will be described below.

  In FIG. 2 (A), the symbol P indicates a pair of parallel plates. The pair of parallel plates P, P is fixed to the lower parallel plate P, but the upper parallel plate P (upper parallel plate P) is the lower parallel plate P ( The lower parallel plate P) is provided so as to be relatively movable. Specifically, the upper parallel plate P is provided so as to move along a direction parallel to the upper surface of the lower parallel plate P while its lower surface is maintained parallel to the upper surface of the lower parallel plate P. .

As shown in FIG. 2A, the liquid crystal LC is disposed between the surfaces of the pair of parallel plates P, P facing each other, and the surfaces of the pair of parallel plates P, P facing each other are An alignment film F is provided for each. The alignment film F is made of a polymer material such as polyimide, for example, and restrains liquid crystal molecules m in the vicinity of the alignment film F (hereinafter referred to as anchoring) when a part of the liquid crystal LC is brought into contact therewith. is there.
In FIG. 2A, as the alignment film F, a liquid crystal molecule m is anchored so that its axial direction is aligned along the left-right direction in FIG. 2 and tilts upward from the right end toward the left end. The case where it was used is shown.

    As described above, when the electric field ef is applied to the liquid crystal LC disposed between the pair of parallel plates P and P so as to intersect the axial direction of the liquid crystal molecule m, the rotation angle of the liquid crystal molecule m becomes small. Since it rotates in the direction (the direction of the arrow in FIG. 2A), a velocity gradient is generated around each liquid crystal molecule m, and a liquid crystal flow is generated.

The liquid crystal flow generated at this time is a flow parallel to the pair of parallel plates P, P (a flow flowing from the left to the right in FIG. 2), but the lower parallel plate P is fixed, whereas the upper parallel plate P Is provided to be movable relative to the lower member P. In addition, the liquid crystal molecules m in the vicinity of the alignment film F are anchored to the alignment film F. In other words, the liquid crystal molecules m in the vicinity of the alignment film F are anchored to the parallel plate P.
Therefore, since the force resulting from the liquid crystal flow is applied to the upper parallel plate P, the upper parallel plate P can be moved relative to the lower parallel plate P along the flow direction of the liquid crystal LC (FIG. 2). (B)
).

(Description of soft actuator using liquid crystal of the present invention)
Next, a soft actuator using the liquid crystal of this embodiment using the above-described principle will be described.
In the principle described above, the pair of parallel plates P and P sandwiching the liquid crystal LC is a flat plate. However, in the soft actuator using the liquid crystal of the present embodiment, at least one or both members sandwich the liquid crystal. It is characterized by having flexibility.

In FIG. 1, a symbol S indicates an object moving sheet in the soft actuator using the liquid crystal of the present embodiment.
The object moving sheet S includes a fixed sheet SP, a moving sheet MP, and a liquid crystal LC disposed between the two.

First, as shown in FIG. 1, the fixed sheet SP is a sheet-like member that is fixed to the surface of the object B that is a target to which the moving sheet MP is relatively moved so as not to move along the surface. . The fixed sheet SP is a sheet formed from a flexible material. For example, vinyl and the like are not particularly limited.
For this reason, since the fixing sheet SP can be bent and deformed, even if the surface of the object B has irregularities, it can be attached so as to be in close contact with the surface (see FIG. 1).
An alignment film F is provided on the upper surface of the fixed sheet SP. The alignment film F is made of a polymer material such as polyimide, and its upper surface (that is, the surface in contact with the liquid crystal LC) is rubbed from right to left in FIG.

As shown in FIG. 1, the moving sheet MP is a member that is arranged at a distance from the fixed sheet SP. This moving sheet MP is also a sheet formed of a flexible material, like the fixed sheet SP. For example, vinyl and the like are not particularly limited.
For this reason, even if the fixed sheet SP is attached to the object B having an uneven surface, the fixed sheet SP is deformed into the same shape as the fixed sheet SP. That is, since the moving sheet MP can be deformed so as to maintain a constant distance from the fixed sheet SP, the object moving sheet S is not attached even if the object moving sheet S is attached to the object B having an uneven surface. The structure can be maintained.
An alignment film F is also provided on the lower surface of the moving sheet MP. Similarly to the alignment curtain F provided on the fixed sheet SP, the alignment film F is made of a polymer material such as polyimide, and its lower surface (that is, the surface in contact with the liquid crystal LC) is shown in FIG. Is rubbed from left to right.

As shown in FIG. 1, a liquid crystal LC is arranged between the upper surface of the fixed sheet SP and the lower surface of the moving sheet MP. The liquid crystal LC is, for example, a nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal, a discotic liquid crystal, or the like, but is not particularly limited as long as the liquid crystal molecules rotate when an electric field is applied.
In the liquid crystal LC, the fixed sheet SP and the moving sheet MP are both provided with the alignment film F, and the surface of the alignment film F is rubbed as described above. For this reason, the liquid crystal molecules m are aligned so that the axial direction thereof is along the left-right direction and is inclined upward from the right end toward the left end (see FIGS. 1B and 2). .

  Further, the soft actuator using the liquid crystal of the present embodiment includes liquid crystal molecule rotating means that can form an electric field ef orthogonal to the upper surface of the fixed sheet SP and the lower surface of the moving sheet MP.

(Description of operation for moving the moving sheet MP)
Next, an operation for moving the moving sheet MP in the soft actuator using the liquid crystal of the present embodiment will be described.

  First, as shown in FIG. 1, the object moving sheet S in the soft actuator using the liquid crystal according to the present embodiment is arranged with the fixed sheet SP along the surface of the object B. Then, the fixed sheet SP and the moving sheet SP of the moving sheet S are deformed into a shape along the surface of the object B.

When the moving sheet S is attached to the surface of the object B, the liquid crystal molecules m can be obtained by applying and removing the electric field ef perpendicular to the upper surface of the fixed sheet SP and the lower surface of the moving sheet MP by the liquid crystal molecule rotating means. Rotates (specifically, the liquid crystal molecules m rotate so as to stand up and fall). Then, liquid crystal flow along both surfaces occurs between the upper surface of the fixed sheet SP and the lower surface of the moving sheet MP. In other words, liquid crystal flow along the surface of the object B occurs.
Since the alignment film F provided on the upper surface of the fixed sheet SP and the lower surface of the moving sheet MP is subjected to the rubbing process as described above, the generated liquid crystal flows from the left to the right in FIG. Become a flow.

In addition, an alignment film F is provided on both the upper surface of the fixed sheet SP and the lower surface of the moving sheet MP, and the liquid crystal molecules m in the vicinity of the alignment film F are substantially fixed to both the sheets SP and MP.
For this reason, when the liquid crystal flow occurs, a force for moving the moving sheet MP in the liquid crystal flow direction is generated, and the moving sheet MP moves in the liquid crystal flow direction.

  Then, the moving sheet MP moves in the direction of the liquid crystal flow, but its shape is the state before the liquid crystal flow is generated along the shape of the surface of the object B due to the liquid crystal flow state or the influence of external force. (See points P1 to P3 in the moving sheet MP in FIG. 1) or move while deforming from the state before the liquid crystal flow is generated.

As described above, in the soft actuator using the liquid crystal according to the present embodiment, since the fixed member SP and the moving member MP of the object moving sheet S are both flexible, the object moving sheet has a curved surface. Can be attached to the object B.
Since the moving sheet SP has flexibility and can be deformed while moving, the moving sheet MP can be moved in the liquid crystal flow direction regardless of the surface shape of the object B. It can also be moved while being deformed by applying an external force.

  Moreover, since the fixed sheet SP and the movable sheet SP can be deformed freely, even if they are attached to the surface of an object whose surface shape changes, the state along the surface shape of the object can be maintained. Moreover, even if the surface shape of the object changes during the movement of the moving sheet MP, the movement of the moving sheet MP can be continued along the changed shape.

  In the above example, the case where the object moving sheet S is attached to the surface of the object B has been described. However, the object moving sheet S is not necessarily attached to the object B for use. For example, the object moving sheet S may be supported by a bar or the like so that the fixed sheet SP is bent, and the moving sheet SP may be moved in that state.

  The fixed sheet BP and the movable sheet MP described above correspond to the fixed member and the movable member as defined in the claims, and the upper surface of the fixed sheet BP and the lower surface of the movable sheet MP are respectively fixed to the fixed member as defined in the claims. This corresponds to the side facing surface and the moving side facing surface of the moving member.

  The moving member is not limited to a sheet, and any moving member may be used as long as it has an alignment film on the lower surface thereof and can move relatively while holding the liquid crystal LC with the fixed sheet BP. For example, a rectangular block or a conical member can be used as the moving member. In this case, the liquid crystal LC only needs to fill the gap between the moving member and the fixed member.

  Further, the fixing member is not limited to the sheet, and any member may be used as long as it has an alignment film on the upper surface and can hold the liquid crystal LC between the movable sheet MP.

Further, the liquid crystal molecule rotating means intersects the liquid crystal molecules m of the liquid crystal LC provided between the upper surface of the fixed sheet SP and the lower surface of the moving sheet MP with the upper surface of the fixed sheet BP and / or the lower surface of the moving sheet MP. If it can be rotated inside, it will not be specifically limited.
For example, if an electrode provided on the fixed sheet SP, an electrode provided on the moving sheet MP, and voltage control means for applying and removing a voltage between the electrodes are provided, the electric field ef as described above can be formed. it can.

  Furthermore, in the above example, the case where the rubbing direction of the alignment film F provided on the fixed sheet SP and the rubbing direction of the alignment film F of the moving sheet MP are opposite by 180 degrees has been described. The direction does not necessarily have to be reversed by 180 degrees. That is, the rubbing directions of the two alignment films F may intersect with each other. In this case, the moving sheet MP is moved in a direction inclined with respect to the rubbing direction of the alignment film F provided on the fixed sheet SP. Can do. For example, if the rubbing direction with respect to the alignment film F is shifted by 90 degrees, the movable sheet MP may be moved at an angle of 45 degrees with respect to the rubbing direction of the alignment film F provided on the fixed sheet SP. it can.

  Furthermore, although the case where the alignment film F is provided on both the fixed sheet SP and the movable sheet MP has been described in the above example, the alignment film F may not necessarily be provided on both. That is, even if the alignment film F is provided only on one of them, the liquid crystal molecules m of the liquid crystal LC can be aligned, so that liquid crystal flow can be generated in a predetermined direction.

  The soft actuator using the liquid crystal according to the present invention is suitable for a moving mechanism for moving a minute object along the unevenness formed by connecting curved surfaces.

SP Fixed plate MP Moving plate F Alignment film LC Liquid crystal m Liquid crystal molecule ef Electric field

Claims (3)

An actuator that moves an object by liquid crystal flow,
A fixed fixing member;
A moving member provided to be movable relative to the fixed member;
Liquid crystal provided between the fixed-side facing surface of the fixing member and the moving-side facing surface of the moving member facing the fixed-side facing surface of the fixing member;
Liquid crystal molecule rotating means for rotating the liquid crystal molecules of the liquid crystal in a plane intersecting the fixed side facing surface of the fixed member and / or the moving side facing surface of the moving member ;
The fixing member is
A soft actuator using liquid crystal, characterized by being formed of a flexible member. An actuator that moves an object by liquid crystal flow,
A fixed fixing member;
A moving member provided to be movable relative to the fixed member;
Liquid crystal provided between the fixed-side facing surface of the fixing member and the moving-side facing surface of the moving member facing the fixed-side facing surface of the fixing member;
Liquid crystal molecule rotating means for rotating the liquid crystal molecules of the liquid crystal in a plane intersecting the fixed side facing surface of the fixed member and / or the moving side facing surface of the moving member ;
The moving member is
A soft actuator using liquid crystal, characterized by being formed of a flexible member. The fixed member and the moving member are both sheet-like members having flexibility, and an object moving sheet comprising the fixed member, the moving member, and the liquid crystal sandwiched between the two. The soft actuator using the liquid crystal according to claim 1, wherein the soft actuator uses liquid crystal.

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