JP2001260097A - Minute object driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a minute object driving device capable of being miniaturized and having a simple structure. SOLUTION: This minute object driving device is provided with: a pair of boards 11, 12 having electrodes 13, 14 arranged in a form spaced apart at a predetermined distance; liquid crystal 15 filled in between the boards; at least one minute object 16 movably arranged in the liquid crystal; and a voltage application means 17 for applying a voltage between the electrodes. In this case, the device is so structured that a liquid crystal orientation layer formed by applying a horizontal orientation process to the liquid crystal along a closed band-like region is formed on each of the surfaces of the electrodes, and the minute object moves in a plane nearly parallel with the board surfaces in a region interposed between the pair of the electrodes by applying a predetermined voltage to the pair of the electrodes from the voltage application means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for driving a minute object, and more particularly to a device for driving a minute object which can be applied to a particle transporting device, a micromotor, a micropump and the like.

[0002]

2. Description of the Related Art In recent years, with the development of micromechanical technology, biotechnology, and the like, interest in a small object driving device capable of causing a minute object to make a circular motion or a rotating motion has been increasing. A method for causing a minute object to move as described above includes the following. A method of irradiating a laser beam passed through an objective lens to a minute object in a fluid, and using a change in momentum caused by refraction of the laser beam at that time; There is a method in which a voltage is applied to a fluid to generate convection, thereby moving a minute object in the fluid.

As the method A, (A-1) a method in which a minute object is rotated (JP-A-5-16826)
No. 5) and (A-2) a technique in which a minute object is made to circularly move on a desired orbit has been proposed.

[0004] As the method B, (B-1)
As shown in FIG. 10, the liquid crystal 95 is disposed between the pair of substrates 91 and 92 on which the electrodes 93 and 94 are formed, respectively, and a region C2 (hereinafter, referred to as a region C2) not interposed between the electrodes 93 and 94. The region is referred to as “electrode non-facing region C”
2 ", and a region between the electrodes 93 and 94 is referred to as an" electrode facing region C1 ".
By applying a voltage to these electrodes 93 and 94, a liquid crystal flow 97 is generated in the direction from one electrode 94 to the other electrode 93 in the electrode facing region C1. A convection vortex 98 is generated, and a rotator 96 is rotated by the convection vortex 98 to generate power (Japanese Patent Laid-Open No. 6-29).
No. 4374) or (B-2) an insulating oil containing a specific compound (organic fluorine compound) is used as a fluid, a plurality of wire-like electrodes are arranged, and a DC voltage is applied to these electrodes. Japanese Patent Application Laid-Open No. H8-210240 proposes a technique in which a movable member (a minute object) disposed in a fluid is rotated by convection of the fluid.

[0005] The rotation direction of the movable member in the above (B-2) is controlled by changing an electrode to which a voltage is applied among a plurality of electrodes. The flow of the fluid is formed by moving from one electrode to the other electrode.

[0006]

However, the above-mentioned prior art has various problems. For example, in the case of the device A, an optical system such as a laser light source and an objective lens is required, and there is a problem that it is difficult to reduce the thickness.
In particular, in the case of the above A-1, it is necessary to provide a plurality of laser light sources, and an optical system for circularly polarizing the laser light is required. In the case of the above A-2, the laser light An optical system or a mechanical system for moving the focal position in a desired moving direction is required, and it has been difficult to reduce the thickness of the apparatus.

On the other hand, in the case of the device B-1, the rotor 9
Numeral 6 is only driven to rotate by the liquid crystal flow 97 on the side of the electrode facing region C1, but not on the side of the electrode non-facing region C2. Therefore, the kinetic energy extracted through the rotor 96 is equal to the applied voltage (ie,
However, there is a problem that the energy conversion efficiency is low because of the small amount of consumed electric energy. Further, in the case of this device, the rotation axis of the rotor 96 must be arranged in a direction along the substrate surface (that is, a direction perpendicular to the paper surface of FIG. 10), and the substrate 91 and the substrate 92 In order to arrange and rotate the rotating shaft between them, a large gap of 100 μm or more (see reference symbol G) must be provided, and there is also a problem that there is a limit in reducing the thickness of the device. Further, in the case of this device, the rotor 96 cannot be disposed in the electrode facing region C1, and the rotator 96 is not arranged in the direction along the substrate surface.
And a wide electrode non-facing region C2 in which the rotor 96 can be arranged.
Has to be provided, and there is a problem that the apparatus is enlarged in the direction.

On the other hand, in the case of the device B-2,
There is a problem that the structure becomes complicated because a plurality of wire-like electrodes are arranged. In addition, in order to reverse the rotation direction of the movable member, it is necessary to reselect a specific electrode from among a plurality of electrodes, and there has been a problem that a driving method and a driving circuit are complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a small object driving device which can be reduced in size and has a simple structure. Another object of the present invention is to provide a small object driving device that reduces waste of power consumption.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made in consideration of the above circumstances. A pair of substrates having electrodes arranged at predetermined intervals and a space filled between the substrates are provided. In a minute object driving device including a liquid crystal, at least one minute object movably disposed in the liquid crystal, and voltage applying means for applying a voltage between the electrodes, a horizontal surface with respect to the liquid crystal is provided on the electrode surface. A liquid crystal alignment layer is provided along the band-like region where the alignment processing is closed, and the minute object is applied to the pair of electrodes by applying a predetermined voltage from the voltage application unit to the pair of electrodes. It is an object of the present invention to provide a small object driving device characterized in that the device is configured to move in a plane substantially parallel to the substrate surface in a region sandwiched between electrodes.

In the present invention, preferred embodiments are shown below. It is preferable that the shape of the closed band-like region is annular. It is preferable that the horizontal alignment process is a rubbing process.

The direction of the rubbing treatment applied to the liquid crystal alignment layer on one electrode surface of the pair of electrodes is opposite to the direction of the rubbing treatment applied to the liquid crystal alignment layer on the other electrode surface. Preferably it is. The direction of the rubbing treatment applied to the liquid crystal alignment layer on one electrode surface of the pair of electrodes may be the same as the direction of the rubbing treatment applied to the liquid crystal alignment layer on the other electrode surface. preferable.

It is preferable that the trajectory of the movement of the minute object is substantially a closed curve. Preferably, the closed curve is a circle. It is preferable that the movement of the minute object is a rotation movement whose rotation axis is in a direction perpendicular to the electrode surface.

It is preferable that the liquid crystal is a nematic liquid crystal. It is preferable that the minute object does not dissolve in the liquid crystal.

It is preferable that the minute object is a dielectric. Preferably, the voltage applied by the voltage applying means is an alternating voltage.

Preferably, the alternating voltage comprises a positive pulse and a negative pulse. It is preferable that the peak value of the positive pulse is different from the peak value of the negative pulse. It is preferable that the frequency of the alternating voltage is 10 Hz or more and 5 kHz or less. It is preferable that the peak value of the alternating voltage is such that an electric field intensity formed between the electrodes is 1 V / μm or more.

It is preferable that a transmission mechanism for transmitting the rotation of the minute object to the outside of the pair of substrates is provided. It is preferable that the transmission mechanism is a rod-shaped structure connected to the minute object, and a long axis direction of the rod-shaped structure is parallel to a rotation axis of the rotation of the minute object. It is preferable that the minute object and the rod-like structure are formed of a polymer of a photopolymerizable compound. Preferably, the photopolymerizable compound is a photoresist.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a micro object driving device according to the present invention will be described with reference to FIGS.
FIG. 1 is a cross-sectional view showing an example of the structure of the minute object driving device according to the present invention. FIG. 2 is a perspective view showing an example of the horizontal alignment processing according to the present invention.

In FIG. 1, reference numerals 11 and 12 are substrates arranged at a predetermined interval. 13 and 14 are electrodes provided on the substrate 11 and the substrate 12, respectively. A liquid crystal alignment layer is provided on the surface of the electrode (omitted in FIG. 1).

Reference numeral 15 denotes a liquid crystal filled between the substrate 11 and the substrate 12. Reference numeral 16 denotes a minute object arranged in the liquid crystal 15. Reference numeral 17 denotes voltage applying means for applying a voltage between the electrodes 13 and 14. In FIG. 1, a spacer for maintaining the interval between the substrates and a seal structure for preventing leakage of the liquid crystal are omitted.

The liquid crystal alignment layers provided on the surfaces of the electrodes 13 and 14 are subjected to a horizontal alignment process for the liquid crystal along a closed band region. The shape of the closed band-shaped region is not particularly limited, but may be an annular shape. The method of the horizontal alignment treatment is not particularly limited, but a rubbing treatment can be used.

The horizontal alignment treatment on the electrode surface according to the present invention will be described with reference to FIG. FIG. 2 is a perspective view of the electrode 14 provided on the substrate 12 as viewed obliquely. In FIG. 2, a liquid crystal alignment layer 18 laminated on the electrode 14 is provided. Closed band 2 shaded on electrode 14
Reference numeral 1 denotes a region subjected to the horizontal alignment processing. In FIG. 2, the area subjected to the horizontal alignment processing has an annular shape.

There is no particular limitation on the method of forming such a closed band-like horizontal alignment processing region. For example, it can be formed by performing a rubbing process along the closed band-shaped region 21. That is, the rubbing cloth is pressed against the liquid crystal alignment layer 18 on the electrode 14, and the rubbing cloth is rubbed in one direction (for example, the arrow direction shown in the figure) along the rubbing direction 22 of the closed curve in FIG. Thereby, a closed band-shaped rubbed area can be formed.

The liquid crystal alignment layer laminated on the electrode 13 shown in FIG. 1 is also subjected to a horizontal alignment process along the closed band like the electrode 14. In the present invention, the direction of the rubbing treatment applied to the liquid crystal alignment layer on one electrode surface is opposite to or the same as the direction of the rubbing treatment applied to the liquid crystal alignment layer on the other electrode surface. Orientation.

The minute object 16 is entirely composed of the liquid crystal 15.
It may be immersed in the liquid crystal 15 or only a part thereof may be immersed in the liquid crystal 15. Also, in FIG.
Is shown only one, but the number is not limited to only one and may be two or more or many. Further, the minute object 16 may be a dielectric, and the liquid crystal 15 may be used.
The material is not particularly limited as long as it does not dissolve in,
For example, polymer beads, metal oxide fine particles, organic molecular aggregates, or the like may be used. Further, the shape itself is not particularly limited, and may be spherical, flat, or acicular. However, one minute object 1
The size of the liquid crystal 6 must be smaller than the liquid crystal layer thickness and movable even when the liquid crystal 15 is immersed in the liquid crystal 15 (even if the liquid absorbs or chemically changes).

The type and structure of the liquid crystal 15 is not particularly limited, but is preferably a liquid crystal capable of exhibiting a nematic phase or a cholesteric phase.

Next, a driving method of the minute object driving device according to the present invention will be described with reference to FIGS. FIG. 3 is a schematic diagram for explaining the movement of a minute object, and FIGS. 4 and 5 are waveform diagrams showing the waveform of an alternating voltage applied to the minute object driving device according to the present invention.

FIG. 3 shows a micro object 16 arranged between the electrode 13 and the electrode 14 of the micro object driving device shown in FIG.
The state observed from above the substrate 11 is shown. A to D shown in FIG. 3 correspond to the four corners of the electrode 13 and the electrode 14.

It is assumed that the liquid crystal alignment layer laminated on the surfaces of the electrodes 13 and 14 has been subjected to a rubbing treatment along an annular territory. The direction of the rubbing treatment applied to the liquid crystal alignment layer on the electrode 13 is clockwise as viewed from above the substrate 11. On the other hand, the direction of the rubbing treatment applied to the liquid crystal alignment layer on the electrode 14 is counterclockwise when observed from above the substrate 11. It is also assumed that the size of the minute object 16 is smaller than the gap distance between the electrodes 13 and 14 and the electrode width.

It is assumed that a rectangular wave (V1> V2) having both polarities as shown in FIG. 4 is applied by the voltage applying means 17. The electrode 14 is grounded. In this case, the minute object 16 moves in a plane substantially parallel to the electrode surface and on a substantially circular orbit whose maximum diameter is the width of the electrode. Minute object 16
Is in a clockwise direction when viewed from the upper surface of the substrate 11. Numeral 31 in FIG. 3 is a curve schematically showing the trajectory of the movement of the minute object 16.

On the other hand, it is assumed that a rectangular wave (V1> V2) having both polarities as shown in FIG. 5 is applied by the voltage applying means 17. Also in this case, the minute object 16 moves in a plane substantially parallel to the electrode surface and on a substantially circular orbit whose maximum diameter is the width of the electrode. The direction of movement of the minute object 16 is as follows.
When viewed from the upper surface of the substrate 11, it is counterclockwise. Note that even if a plurality of minute objects are arranged between the electrodes, it is possible to cause all the minute objects to move as described above by applying the rectangular wave.

For example, when the rectangular wave shown in FIG. 4 is applied, all the minute objects move on a substantially circular orbit in a plane substantially parallel to the electrode surface and with the maximum width of the electrode. Exercise. The trajectory radius of the movement of the minute object existing near the electrode edge is larger than the trajectory radius of the movement of the minute object existing near the center of the electrode. The direction of movement of each minute object is clockwise as viewed from the upper surface of the substrate 11.

On the other hand, when the rectangular wave shown in FIG. 5 is applied, all the minute objects move in a plane substantially parallel to the electrode surface.
And it moves on a substantially circular orbit with the maximum diameter being the width of the electrode. The trajectory radius of the movement of the minute object existing near the electrode edge is larger than the trajectory radius of the movement of the minute object existing near the center of the electrode. The direction of the motion of each minute object is counterclockwise as viewed from the upper surface of the substrate 11.

Next, a case where a minute object whose width is about the electrode width and whose height is smaller than the distance between the electrodes is arranged between the electrodes will be described. In this case, if the above-described short wave is applied between the electrodes, the minute object shows a spinning motion. The rotation axis of the rotation is perpendicular to the electrode surface. When the rectangular wave shown in FIG. 4 is applied, the minute object shows a clockwise rotation when observed from the upper surface of the substrate 11. On the other hand, when the rectangular wave shown in FIG. 5 is applied, the minute object shows a counterclockwise rotation when observed from the upper surface of the substrate 11.

The rectangular wave shown in FIG. 4 is a rectangular wave having a polarity opposite to that of the rectangular wave shown in FIG. That is, by inverting the polarity of the rectangular wave applied between the electrodes, it is possible to invert the direction of the above-described motion (circular motion and rotational motion) of the minute object disposed between the electrodes.

Next, the liquid crystal alignment layer on the electrode 13 and the electrode 14
The case where the rubbing direction applied to the upper liquid crystal alignment layer is clockwise as viewed from above the substrate 11 will be described. In this case, when the short wave shown in FIGS. 4 and 5 is applied between the electrodes, the minute object shows a counterclockwise circular motion or a rotating motion regardless of the shape of the short wave.

In the case where the minute object shows a rotating motion, it is possible to connect a rotating shaft as a power transmission mechanism to the minute object and use the minute object driving device as a micromotor.
Although the details of the movement mechanism of the minute object as described above are unknown, it is considered that the movement is caused by the liquid crystal flowing in the in-plane direction of the electrode induced by the electric field.

If the rectangular wave is continuously applied between the electrodes, it is presumed that liquid crystal flows in a direction parallel to the rubbing direction near the electrodes. In the present invention, since the rubbing treatment is performed along a closed curve, it is presumed that a liquid crystal flow is formed along the curve.

However, it is presumed that the direction of the liquid crystal flow depends on the direction of the rubbing treatment. For this reason, when the directions of the rubbing treatment performed on the pair of electrodes are opposite to each other, the direction of the liquid crystal flow formed near one of the electrodes is
It is assumed that the direction is opposite to the direction of the flow of the liquid crystal formed near the other electrode. Therefore, it is considered that the minute object approaches one of the electrodes due to the electric field generated by the applied rectangular wave, and moves due to the flow of the liquid crystal formed near the electrode.

Therefore, depending on the material of the minute object, FIG.
Even if a rectangular wave as shown in FIG. 4 is applied, unlike the above description, it may show a counterclockwise circular motion (or a rotational motion).

In the above description, a rectangular waveform is shown as the voltage waveform applied between the electrodes to drive the minute object. However, in the present invention, the voltage waveform is not limited to a rectangular wave, and may be a sine wave, a triangular wave, or a sawtooth wave as long as the alternating voltage satisfies the following characteristics.

The alternating voltage according to the present invention is preferably composed of a positive pulse and a negative pulse, and the peak value (V1) of the positive pulse and the peak value (V2) of the negative pulse are preferably different. . In order to generate such an alternating voltage, the alternating voltage having the same peak value of the positive pulse and the peak value of the negative pulse may be combined with the offset voltage. The magnitude of the absolute value of the offset voltage is not particularly limited as long as the desired motion can be expressed in the minute object.

When the frequency and peak value V1 and V2 of the alternating voltage are small, the liquid crystal flow is small. On the contrary, when the frequency and peak value are large (the flow is large), a minute object is adsorbed on the electrode. After all,
In any case, the minute object cannot move as desired.
Therefore, the frequency and peak value of the alternating voltage applied between the pair of electrodes must be in a range where the minute object can move. The range varies depending on the type of liquid crystal, the material and size of the minute object, the material of the liquid crystal alignment layer, and the like.
Hz or less, more preferably 50 Hz
It is not less than 5 kHz. Peak values V1, V2 of the alternating voltage
Indicates that the electric field strength formed between the electrodes is 1 V / μm or more.
V / μm or less, more preferably 3 V / μm or more and 13 V /
μm or less, more preferably 10 V / μm or more and 13 V /
The range of not more than μm is preferable.

[0044]

The present invention will be described below in more detail with reference to examples.

Embodiment 1 In this embodiment, a micro object driving device as shown in FIG. 6 was prepared. In this embodiment, the substrate 61 and the substrate 62 are glass substrates, and are 1 cm × 1 cm square.
The distance between the substrates is 8 μm. In FIG. 6, the spacer for maintaining the interval is omitted. The electrodes 63 and 64 are ITO electrodes, and are 8 mm × 8 mm square. Each ITO
A rubbed polyimide thin film is laminated on the electrode along the closed band region. 65 is a nematic liquid crystal (trade name BL9, manufactured by Merck). Reference numeral 66 denotes a minute object. In this example, polymer beads having a particle size of 3 μm (trade name: Micropearl BB, manufactured by Sekisui Fine Chemical Co., Ltd.) were used. Reference numeral 67 denotes voltage applying means for applying a voltage between the electrodes.

FIG. 7 shows the shape of the closed band-like region according to this embodiment. FIG. 7 is a schematic view of the electrode observed from above the electrode, and the rubbed area 71 is indicated by oblique lines. The rubbing process is performed along a circle 71 shown in FIG.

In this embodiment, as shown in FIG. 8, a rubbing cloth 82 is pressed onto the electrode 81 to rotate the electrode in one direction about an axis passing through the center of the electrode 81 and perpendicular to the electrode surface. A rubbing treatment was performed on the polyimide thin film on the electrode surface. By performing such a rubbing process, an annular rubbing region as shown in FIG. 7 was formed.

The rubbing treatment was performed on the liquid crystal alignment layer on the electrode 63 in a clockwise direction as viewed from above the substrate 61. On the other hand, the liquid crystal alignment layer on the electrode 64 was subjected to rubbing in a counterclockwise direction when observed from above the substrate 61.

Next, the electrode 63 and the electrode 6 are
4, the following two types of rectangular wave voltages were alternately applied.
However, in each case, the electrode 64 is grounded. (Square wave voltage 1) A rectangular wave voltage as shown in FIG.
V1 is 86 V, -V2 is -54 V, and the frequency is 500 Hz and the duty ratio is 50%. (Square wave voltage 2) A rectangular wave voltage as shown in FIG.
V1 is 54 V, -V2 is -86 V, and the frequency is 500 Hz and the duty ratio is 50%.

The response of the polymer beads during the application of the rectangular wave voltage was observed from above the electrode 63 with an optical microscope. When the short-wave voltage 1 was applied, all the polymer beads showed a clockwise circular motion in a plane substantially parallel to the electrode surface. On the other hand, when the rectangular wave voltage 2 was applied, all the polymer beads showed a counterclockwise circular motion in a plane substantially parallel to the electrode surface. That is,
It has been found that the polymer beads can be made to circularly move by the applied rectangular wave voltage, and the direction of the movement can be controlled.

Example 2 In this example, polymer beads (trade name: Micropearl BB, manufactured by Sekisui Fine Chemical Co., Ltd.) having a diameter of 14 μm were used as minute objects, and the substrate interval was set to 25 μm.
A micro object driving device having the same configuration as that of Example 1 was used except that the size of the electrode was set to 20 μm × 20 μm.

Next, a voltage is applied between the pair of electrodes by the voltage applying means.
The two types of rectangular wave voltages used in Example 1 were alternately applied. However, in each case, the electrode 64 is grounded. The response of the polymer beads during the application of the rectangular wave voltage was observed from above the electrode 63 with an optical microscope.

When the rectangular wave voltage 1 was applied, the polymer beads showed a clockwise rotation with the direction perpendicular to the electrode surface as the axis of rotation. On the other hand, when the short-wave voltage 2 was applied, the polymer beads showed a counterclockwise rotation with a rotation axis perpendicular to the electrode surface. That is, it was found that the polymer beads can be caused to rotate by the applied short-wave voltage, and the rotation direction can be controlled.

Embodiment 3 In this embodiment, a minute object driving device having the same configuration as that of Embodiment 1 was used except for the following four points. The points of change are that the gap between the electrodes is 25 μm, the shape of the minute object is a rectangular parallelepiped (8 mm × 3 mm × 10 μm), (Length: 1 cm) and a circular hole (diameter: 800 μm) for taking the rod out of the substrate was formed in one of the substrate and the electrode.

FIG. 9 is a schematic cross-sectional view of the minute object driving device used in this embodiment. 101 and 102 are glass substrates. The distance between the substrates is 25 μm. 103 and 104 are IT
It is an O electrode (8 mm x 8 mm). Reference numeral 105 denotes a rectangular parallelepiped minute object. 106 is a nematic liquid crystal (brand name BL)
9, Merck). Reference numeral 107 denotes a rod connected to the minute object 105. 108 denotes the substrate 101 and the electrode 10
3 is a circular hole through which the rod 107 is provided. Reference numeral 109 denotes voltage applying means for applying a voltage between the electrodes. Note that FIG.
In this case, the spacer for maintaining the interval is omitted.

Next, a method for arranging a minute object having a columnar rod connected between the electrodes will be described. First, a rectangular (8 mm × 3 mm) hole having a depth of 10 μm is formed in a glass substrate by a known lithographic technique. In this hole,
A mixture of 50 parts by weight of a photopolymerizable compound and 1 part by weight of a photopolymerization initiator in the same volume as the hole is poured, and the hole is covered with a glass plate. The photopolymerizable compound is a mixture of 45 parts by weight of 4-hydroxybutyl acrylate and 5 parts by weight of 1,6-hexanediol diacrylate.

Next, the above-mentioned photopolymerizable compound was irradiated with ultraviolet rays to produce a rectangular parallelepiped fine object made of a polymer compound. Take this minute object out of the hole in the glass substrate,
Place on a hot plate set at 110 ° C. next,
A thick film negative resist (THB-234) is formed on the minute object.
N, manufactured by JSR Co., Ltd.). As a result, a fine rod was able to be adhered to the minute object.

The fine rod made of a thick resist is
It was formed by a known lithographic technique. That is, by sequentially performing mask exposure, rinsing, and baking treatment on a 500 μm thick resist layer formed on a silicon substrate, fine rods made of the thick resist having the above-described shape can be formed. In this example, a minute stick made of a thick film resist was peeled off from the silicon substrate and adhered to the minute object.

Next, a minute object to which the minute rod is connected is placed on the electrode 104. Then, a spacer having a diameter of 25 μm is arranged around the substrate 102 provided with the electrode 104. Then, the electrode 1 formed by a known etching process
The minute rod was passed through the hole of the substrate 03 and the substrate 101 while observing it with a stereoscopic microscope. Thereafter, liquid crystal was injected into the cell hollow portion, and the substrates were fixed with an adhesive. Through such steps, the micro object driving device according to the present embodiment could be obtained.

Next, a voltage is applied between the pair of electrodes by the voltage applying means.
The two types of rectangular wave voltages used in Example 1 were alternately applied. However, in each case, the electrode 104 is grounded.
The response of the minute object and the response of the minute rod during the application of the short-wave voltage were observed from above the electrode 103.

When the rectangular wave voltage 1 was applied, the minute object showed clockwise rotation with the direction perpendicular to the electrode surface as the axis of rotation. At the same time, the minute rod also showed a clockwise rotation with the direction perpendicular to the electrode surface as the axis of rotation.

On the other hand, when the rectangular wave voltage 2 was applied, the minute object showed a counterclockwise rotation with the direction perpendicular to the electrode surface as the rotation axis. At the same time, the fine rod also showed a counterclockwise rotation with the direction perpendicular to the electrode surface as the axis of rotation.

That is, the rotation of the minute object could be transmitted to the outside of the substrate through the minute rod by the applied rectangular wave voltage. The rotation direction of the minute rod could be controlled by a rectangular waveform.

[0064]

As described above, according to the present invention, a laser light source, complicated electrodes and a driving circuit are not required unlike the conventional apparatus, so that the structure of the apparatus can be simplified and its thickness can be reduced. I can do it. Furthermore, according to the present invention, when a rotating shaft is connected to each minute object as a power transmission mechanism,
The direction in which the rotation axis extends is not a direction along the substrate surface but a direction perpendicular to the substrate surface. Therefore, there is no need to provide a gap between the substrate and the substrate so that the rotation shaft is arranged and rotated. In this respect, the thickness of the device can be reduced.

Further, according to the present invention, the minute object does not move in the non-electrode non-facing region unlike the conventional device,
It moves in the electrode facing area. Therefore, the non-electrode non-facing region can be reduced without considering the space for the movement of the minute object, and the device can be downsized accordingly.

Furthermore, according to the present invention, the rotation of the minute object is performed by the liquid flows generated in opposite directions on both sides of the minute object, and is performed only by the liquid flow on one side as in the conventional apparatus. is not. Therefore, even when the rotating shaft is connected to the minute object as a power transmission mechanism, the conversion efficiency in converting electric energy to kinetic energy is improved, and waste of power consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a structure of a minute object driving device according to the present invention.

FIG. 2 is a perspective view showing an example of a horizontal alignment process according to the present invention.

FIG. 3 is a schematic diagram for explaining movement of a minute object.

FIG. 4 is a waveform diagram showing a waveform of an alternating voltage applied to the minute object driving device according to the present invention.

FIG. 5 is a waveform diagram showing a waveform of an alternating voltage applied to the minute object driving device according to the present invention.

FIG. 6 is a cross-sectional view illustrating the structure of the minute object driving device according to the first embodiment of the present invention.

FIG. 7 is a perspective view showing another example of the horizontal alignment processing according to the present invention.

FIG. 8 is a schematic diagram for explaining a rubbing method according to the present invention.

FIG. 9 is a cross-sectional view illustrating a structure of a minute object driving device according to a third embodiment of the present invention.

FIG. 10 is a cross-sectional view illustrating an example of a structure of a conventional minute object driving device.

[Explanation of symbols]

 11, 12 Substrate 13, 14 Electrode 15 Liquid crystal 16 Micro object 17 Voltage applying means 18 Liquid crystal alignment layer 21 Horizontal alignment processing area 22 Rubbing processing direction 31 Motion locus of micro object 61, 62 Substrate 63, 64 Electrode 65 Liquid crystal 66 Micro object 67 Voltage application means 71 Rubbing treatment area 81 Electrode 82 Rubbing cloth 83 Electrode center 84 Rotation axis 91, 92 Substrate 93, 94 Electrode 95 Liquid crystal 96 Rotator 97 Liquid crystal flow 98 Convection vortex 101, 102 Substrate 103, 104 Electrode 105 Micro object 106 Liquid crystal 107 minute rod 108 hole 109 voltage applying means

Claims (20)

[Claims] 1. A pair of substrates having electrodes arranged at a predetermined interval, a liquid crystal filled between the substrates,
In a micro object driving device comprising at least one micro object movably arranged in the liquid crystal and voltage applying means for applying a voltage between the electrodes, a horizontal alignment process for the liquid crystal is performed on the electrode surface. A liquid crystal alignment layer provided along a closed band-shaped region is provided, and the minute object is sandwiched between the pair of electrodes by applying a predetermined voltage to the pair of electrodes from the voltage applying unit. A small object driving device which is configured to move in a plane substantially parallel to the substrate surface in a region where the substrate is moved. 2. The device for driving a minute object according to claim 1, wherein the shape of the closed band-like region is annular. 3. The device according to claim 1, wherein the horizontal alignment process is a rubbing process. 4. A rubbing direction applied to a liquid crystal alignment layer on one electrode surface of the pair of electrodes is opposite to a rubbing direction applied to a liquid crystal alignment layer on the other electrode surface. The device for driving a minute object according to claim 3, wherein the device is oriented. 5. A rubbing direction applied to a liquid crystal alignment layer on one electrode surface of the pair of electrodes is the same as a rubbing direction applied to a liquid crystal alignment layer on the other electrode surface. The device for driving a minute object according to claim 3, wherein the device is oriented. 6. The small object driving device according to claim 1, wherein the trajectory of the movement of the small object is substantially a closed curve. 7. The device for driving a minute object according to claim 6, wherein the closed curve is a circle. 8. The device for driving a minute object according to claim 1, wherein the movement of the minute object is a rotation with a direction perpendicular to the electrode surface as a rotation axis. 9. The device according to claim 1, wherein the liquid crystal is a nematic liquid crystal. 10. The device according to claim 1, wherein the minute object does not dissolve in the liquid crystal. 11. The device for driving a minute object according to claim 10, wherein the minute object is a dielectric. 12. The device according to claim 1, wherein the voltage applied by the voltage applying means is an alternating voltage. 13. The device according to claim 12, wherein the alternating voltage comprises a positive pulse and a negative pulse. 14. The peak value of the positive polarity pulse is different from the peak value of the negative polarity pulse.
The device for driving a small object according to the above. 15. The device according to claim 12, wherein the frequency of the alternating voltage is 10 Hz or more and 5 kHz or less. 16. The micro object driving device according to claim 12, wherein the peak value of the alternating voltage is such that an electric field intensity formed between the electrodes is 1 V / μm or more. 17. The micro object driving device according to claim 8, further comprising a transmission mechanism for transmitting the rotation of the micro object to outside the pair of substrates. 18. The method according to claim 18, wherein the transmission mechanism is a rod-shaped structure connected to the minute object, and a major axis direction of the rod-shaped structure is parallel to a rotation axis of the rotation of the minute object. The micro object driving device according to claim 17. 19. The micro-object and the rod-shaped structure,
19. The device for driving a minute object according to claim 18, wherein the device is made of a polymer of a photopolymerizable compound. 20. The apparatus according to claim 19, wherein the photopolymerizable compound is a photoresist.