JP4628755B2 - Moving mechanism and small camera, goniometer and fiberscope using the same - Google Patents

Description

  The present invention relates to a position moving mechanism used for a still camera, a video camera, a mobile phone camera, and the like, and a small camera using the same.

  Still cameras, video cameras, mobile phone cameras, etc. project images of objects to be photographed onto image sensors such as solid-state image sensors, charge-coupled devices (CCD), and complementary metal oxide semiconductor integrated circuits (CMOS) through lenses. It is a mechanism to do. In order to project a focused image on the image sensor, it is necessary to adjust the distance between the lens and the image sensor in accordance with the distance between the lens and the object to be photographed.

  In a still camera or a video camera, in order to focus, the distance between the lens and the image sensor is adjusted by mechanically moving the lens using a small motor or the like. On the other hand, it is difficult to provide a mechanical mechanism for moving a lens in a micro camera mounted on a mobile phone due to size limitations. Therefore, focusing is not necessary using a wide-angle lens having a large depth of focus. However, a camera for a mobile phone is also required to have a function of photographing a distant object to an object at a short distance of about several centimeters. Since the current wide-angle lens alone cannot satisfy such a function, a mechanism for focusing on a small camera is required.

  There are many methods for moving the lens without using a motor. Among them, the method using a piezoelectric element is simple and can be miniaturized. When an electric field is applied to the piezoelectric body in a predetermined direction, the magnitude of the electric polarization moment of the piezoelectric body changes and expands and contracts accordingly. The lens can be moved by utilizing this expansion and contraction.

  Apart from this, a method of focusing by changing the focal length by changing the lens shape has been proposed.

  In Patent Document 1, hydraulic oil is sealed in a pressure chamber having at least one surface formed of a transparent elastic film, and the focal length is variably controlled by deforming the transparent elastic film by the pressure of the hydraulic fluid acting on the transparent elastic film. Such a lens is written. In this lens, the deformation shape of the transparent elastic film is optimized so as to reduce the occurrence of lens aberration, and the pressure of the hydraulic oil in the pressure chamber is measured by a pressure sensor formed on the transparent elastic film. By adjusting the pressure of the hydraulic oil based on the above, fluctuations in focal length due to thermal expansion and contraction of the hydraulic oil are suppressed.

  In Patent Document 2, by applying a potential difference between the first electrode and the conductive elastic plate, a suction force due to a Coulomb force is generated to narrow the distance between the two, and as a result, the transparent liquid discharged from the distance between the two electrodes A variable-focus lens is described which has a volume and deforms the central portion of the transparent elastic plate so that it protrudes convexly toward the transparent liquid.

Patent Document 3 proposes a variable focus lens using an electrowetting phenomenon. A transparent insulating film treated with water repellency is formed on the transparent electrode, and droplets are placed thereon, and the droplets are used as lenses. When a voltage is applied between the lower electrode and the liquid, an electric charge is generated at the liquid / insulating film interface and the liquid / insulating film interface tension is lowered, so that the shape of the liquid changes. This change realizes a lens having a variable focal length.
Japanese Patent Laid-Open No. 8-114703 JP 11-133210 A Special Table 2001-519539

The method of moving a lens using a piezoelectric body has a simple structure and can be reduced in size. For example, when an electric field is applied between two surfaces of a ferroelectric material processed into a plate shape, when the electric dipole is perpendicular to this surface, the piezoelectric material expands and contracts in the in-plane direction. For example, when LiNbO ₃ is used as the ferroelectric, the plate thickness is 0.1 mm, the plate area is 10 mm long, and the width is 10 mm, it is necessary to apply a voltage close to 1000 V in order to reduce it by 2 μm in the in-plane direction. . The applied voltage can be lowered to some extent by devising a ferroelectric material having a high piezoelectric constant and its shape, but it is generally necessary to apply a voltage of several hundred volts to the piezoelectric material. It is difficult to apply such a voltage with a device such as a mobile phone.

  In the methods of Patent Documents 1 to 3, the applied voltage may be small as compared with the case where a piezoelectric body is used. However, in such a method, it is difficult to precisely control the shape of the lens, and it is difficult to capture a clean image without distortion. In Patent Document 3, the shape of the lens becomes spherical due to the surface tension of the liquid. In order to capture a clearer image, an aspherical lens with a hyperbolic lens shape is necessary, but the method of Patent Document 3 is difficult.

  It is an object of the present invention to provide a moving mechanism that can be easily reduced in size and can be driven at a low voltage, in order to adjust the distance between the lens and the image pickup element in order to adjust the focus of the camera, instead of changing the shape of the lens. Furthermore, a small camera using this moving mechanism is provided.

  In the moving mechanism of the present invention, a liquid is disposed between the first structure and the second structure, and by applying a voltage to the liquid, the shape of the liquid is changed by an electrowetting phenomenon, so that the first The distance between one structure and the second structure is adjusted.

  In another moving mechanism of the present invention, a liquid is disposed in a gap between the first structure and the second structure, the first structure and the second structure are both in contact with the liquid, and the first structure and A moving mechanism having a binding force that prevents the second structures from separating from each other, the first structure having a surface in contact with the liquid, the first electrode, and an insulating film formed on the first electrode And a second electrode having a second water-repellent film formed on the surface of the second structure body on the side in contact with the liquid. The liquid is in contact with both the second electrode and the second water-repellent film, and includes means for applying a voltage between the first electrode and the second electrode, and changing the voltage causes electrolysis. The surface of the first structure and the second structure is adjusted by changing the shape of the liquid by a wetting phenomenon. It is characterized in.

  In the camera of the present invention, a liquid is disposed between the first structure and the second structure, and by applying a voltage to the liquid, the shape of the liquid is changed by an electrowetting phenomenon, so that the first The distance between the imaging element and the lens is adjusted by a moving mechanism that adjusts the distance between the structure and the second structure.

  In the goniometer of the present invention, a liquid is disposed between the first structure and the second structure, and a voltage is applied to the liquid to change the shape of the liquid by an electrowetting phenomenon. A moving mechanism that adjusts the distance between the structure and the second structure is used.

  In the fiberscope of the present invention, a liquid is disposed between the first structure and the second structure, and by applying a voltage to the liquid, the shape of the liquid is changed by an electrowetting phenomenon, and the first The direction of the image sensor is adjusted by a moving mechanism that adjusts the distance between one structure and the second structure.

  The present invention can provide a position moving mechanism that can be easily downsized and driven at a low voltage, and can further provide a small camera using the moving mechanism. This moving mechanism can also be used as a position moving mechanism for a micromachine.

  The present inventor has found that a position moving mechanism that can be easily downsized and driven at a low voltage can be realized by using the electrowetting phenomenon. Then, it has been found that if this moving mechanism is used, a small camera capable of accurately controlling the focus can be realized.

  The “electrowetting phenomenon” in the present invention means that the interfacial tension between the liquid and the substrate surface changes due to a change in the charge density in the vicinity of the substrate surface with which the liquid is in contact. A phenomenon in which the wettability between materials changes.

  First, the electrowetting phenomenon will be described with reference to FIGS. 7A-B. 7A-B, 701 is a liquid, 702 is a water repellent film, 703 is a base material, 704 is an electrode, 705 is a contact angle when no voltage is applied, 706 and 712 are droplet heights, and 707 is a liquid. A vector indicating the surface tension, 708 is a vector indicating the surface energy of the water repellent film, 709 is a vector indicating the interface tension between the liquid and the water repellent film, 711 is a contact angle of the liquid when a voltage is applied, and 713 is an interface when the voltage is applied Tension, 714 is a platinum wire, and 715 is a voltage applying means.

  As shown in FIG. 7A, when a droplet is placed on the lower electrode / insulating film / water-repellent film, the droplet has a contact angle θ represented by Young's formula (1) below.

γs = γlcosθ + γls0 (1)
(Where γs is the surface tension of the water-repellent film, γl is the surface tension of the liquid, and γls0 is the interfacial tension between the liquid and the water-repellent film.)
As shown in FIG. 7B, when a thin electrode line is inserted into the liquid and a voltage V is applied between the electrode line and the lower electrode, an electric charge is generated at the interface between the liquid and the water repellent film. Tension decreases.

  When the capacitor capacity per unit area formed by the insulating film and the water repellent film is C and the applied voltage is V, the following equation (2) holds.

γls = γls0 − 1/2 × C × V ² (2)
(However, γls0 is the interfacial tension when V = 0.)
The following equation (3) can be derived from the equations (1) and (2).

cosθ (V) = cosθ (0) + 1/2 × C × V ² (3)
(However, cosθ (V) is cosθ at voltage V, and cosθ (0) is cosθ with V = 0.)
Therefore, as shown in FIG. 7B, θ is reduced by applying a voltage. Along with this, the contact area between the liquid and the water repellent film is increased, and the height of the liquid surface is decreased.

  FIG. 8A is a schematic diagram of two flat plates sandwiched between convex liquids, and FIG. 8B is a schematic diagram of two flat plates sandwiched between liquids whose shape has changed due to an electrowetting phenomenon. 8A-B, 801 is a liquid sandwiched between two flat plates, 805, 806, 810, 811 are contact areas between the plate and liquid, 804, 813 are convex shapes, 807, 812 are intervals between the two flat plates, 808 , 809, 814, and 815 are drag forces that the plate receives from the liquid.

  FIG. 8A is a schematic diagram illustrating a state in which two flat plates sandwich liquid. It is assumed that the lower plate is fixed so that it does not move, and gravity is working downward in the paper. It is assumed that the liquid shape 804 (hereinafter referred to as the liquid shape) of the portion not in contact with the surface is a convex shape. At this time, the internal pressure of the liquid is higher than the external pressure by ΔP. Accordingly, the liquid exerts a pressure ΔP on the plate surface. ΔP is obtained from the Young-Laplace equation (4) shown below.

ΔP = 2γl / R0 (4)
(However, γl is the surface tension of the liquid and R0 is the radius of curvature of the liquid.)
When the contact area between the upper flat plate and the liquid is S, the plate receives a drag force of 2γl / R0 × S upward. Since the upper plate is balanced by the force and gravity from this liquid, the two plates are kept at a constant distance.

  Here, consider the case where the contact angle between the liquid and the two surfaces is reduced using the electrowetting phenomenon. FIG. 8B is a schematic diagram when the contact angle of the liquid in FIG. 8A is reduced by the electrowetting phenomenon. As the contact angle decreases, the liquid spreads and the height of the liquid decreases, so the surface spacing decreases. Accordingly, the contact area between the liquid and each surface and the radius of curvature of the liquid increase.

  At this time, the upward force acting on the upper flat plate is 2γl / R1 × S ′. Here, R1 and S ′ are the radius of curvature of the liquid and the contact area between the liquid and the upper plate, respectively. The distance between the two surfaces is kept constant by this repulsive force and gravity. Therefore, if the electrowetting phenomenon is used, the distance between the two surfaces can be adjusted.

  The position movement mechanism of the present invention is shown below.

(Position moving mechanism 1)
In FIG. 1, 101 is the first structure, 102 is the second structure, 111 is the base material of the first structure, 112 is the base material of the second structure, 103 is the liquid, 107 is the first water repellent film, Reference numeral 108 denotes a second water repellent film, 106 denotes an insulating film, 105 denotes a first electrode, 109 denotes a second electrode, and 110 denotes means for applying a voltage between the first electrode and the second electrode.

  As shown in FIG. 1, the liquid 103 is arrange | positioned in the clearance gap between the 1st structure 101 and the 2nd structure 102, and both the said 1st structure and the 2nd structure are in contact with the said liquid. A binding force 104 acts so that the first structure and the second structure are not separated from each other. This is due to the surface tension of the liquid. The surface of the first structure in contact with the liquid has a first electrode 105, an insulating film 106 formed on the first electrode, and a first water repellent film 107 formed on the insulating film. Consists of. A second electrode 109 having a second water-repellent film 108 formed on the periphery thereof is disposed on the surface of the second structure that is in contact with the liquid. The liquid is in contact with both the second electrode and the second water repellent film. By applying a voltage between the first electrode and the second electrode and changing the voltage, an electrowetting phenomenon is caused, and the shape of the liquid is changed to change the surfaces of the first structure and the second structure. Adjust the interval.

  As shown in FIG. 1, the liquid 103 is always in contact with the second water repellent film 108 around the second electrode 109. Even if a voltage is applied between the first electrode and the second electrode, no charge is induced at the interface between the second water-repellent film and the liquid, so the static contact angle θ113 between the second water-repellent film and the liquid is always constant. is there. In particular, when θ is 90 degrees or more, the liquid always has a convex shape, the internal pressure of the liquid becomes higher than the external pressure, and a drag in a direction that widens the gap between the structures 1 and 2 is generated. This drag balances with the binding force 104 acting on the two structures, and the distance between the two structures is maintained. When a voltage is applied between the first electrode and the second electrode, the liquid on the first water repellent film spreads due to the electrowetting phenomenon, and the height of the liquid changes, so that the distance between the structure 1 and the structure 2 is reduced. In this way, by adjusting the voltage to be applied, the distance between the two structures can be controlled. In the present invention, the preferred static contact angle θ with respect to the liquid second water-repellent film is in the range of 90 ° to 150 °. When the static contact angle θ is less than 90 degrees, the liquid spreads and the function of widening the gap between the structures 1 and 2 is deteriorated.

(Position moving mechanism 2)
In a preferred embodiment of the present invention, in the moving mechanism 1, the filling liquid that does not mix with the liquid is filled between the first structure and the second structure, and the filling liquid has a concave shape, A binding force is generated by the surface tension of the filling liquid.

  FIG. 2 is a schematic view of an example of the position movement mechanism of the present invention. The filling liquid 21 is filled between the first structure 101 and the second structure 102, and the liquid surface shape 22 of the filling liquid 21 in a portion not in contact with the two structures and the liquid 103 (hereinafter, referred to as the liquid surface shape 22) (Referred to as liquid shape) is concave. This concave filling liquid serves as a binding force for the two structures. Other reference numerals are the same as those in FIG.

  FIG. 9 shows a mechanism that generates a binding force when the filling liquid has a concave shape. When there are two flat plates 91 and 92 sandwiched between liquids and the liquid is concave, the liquid has a negative pressure by ΔP ′ with respect to the external pressure, and a pressure is applied to bring the two surfaces closer. ΔP ′ can be obtained in the same manner as the equation (4).

ΔP '= 2γl / Rx (5)
(However, γl is the surface tension of the liquid and Rx is the radius of curvature of the liquid surface.)
Accordingly, when the contact area between the flat plate and the liquid is Sx, the flat plate is attracted by a force of ΔP ′ × Sx. Note that 93 is a liquid sandwiched between two flat plates, 94 is a concave shape, 95 and 96 are contact areas between the plate and the liquid, and 97 and 98 are attractive forces that the plate receives from the liquid.

  According to the present invention, since the binding force is generated by the filling liquid, the binding force generation mechanism is simplified, and the size of the position movement mechanism can be reduced.

(Position moving mechanism 3)
A more preferred position movement mechanism of the present invention is that in the position movement mechanism 1, there is a hydrophilic region in which the water-repellent film is not formed on the insulator of the first structure, and the liquid contacts the hydrophilic region. is doing.

  FIG. 3 shows a schematic diagram of an example of the position moving mechanism. In this position moving mechanism, since the liquid 103 is constantly at the position centered on the hydrophilic position 31, the positions of the two structures can be controlled with good reproducibility.

  In general, the position of the liquid in contact with the water-repellent region is likely to change. This is clear from the fact that the liquid placed on the fluororesin plate easily rolls off when the plate is tilted. As shown in FIGS. 10A and 10B, even when the applied voltages are the same in the two structures, if the position of the liquid changes, the distance between the structures and the positional relationship between the structures may be different. 11A-B, 301 is a liquid, 302 is a substrate, and 303 is a hydrophilic region. As shown in FIGS. 11A-B, when the liquid is in contact with both the hydrophilic region and the water repellent region, the liquid is more hydrophilic as shown in FIG. 11B than at the position shown in FIG. 11A. The one that is located at the center of the region is more stable in terms of energy. Therefore, in this position moving mechanism, a part of the liquid is in contact with the hydrophilic region, and therefore the center of the liquid is always located in this hydrophilic region. As a result, even if the operation of applying or not applying a voltage between the first electrode and the second electrode is repeated, the center position of the liquid is always in the hydrophilic region, so the positional relationship between the two structures is reproduced. It becomes possible to control with good performance.

(Position moving mechanism 4)
In a more preferred position movement mechanism of the present invention, in the position movement mechanism 1, the hydrophilic region has a concave shape.

  FIG. 4 is a schematic diagram showing an example of the position movement mechanism of the present invention. If the hydrophilic region 41 has a concave shape, the contact area between the liquid and the hydrophilic portion increases, so the center of the liquid tends to stay in the concave portion, and the central position of the liquid is kept constant even if the position movement operation is repeated. . Therefore, the position of the two structures can be controlled with high reproducibility.

(Position moving mechanism 5)
In a more preferred position movement mechanism of the present invention, in the first structure, the area of the first electrode is smaller than the area of the water-repellent film, and the liquid is positioned directly above the electrode.

  FIG. 5 is a schematic diagram showing an example of the position movement mechanism of the present invention. When a voltage is applied between the first electrode and the second electrode, the voltage spreads due to the liquid electrowetting phenomenon on the water-repellent film above the electrode. However, since the interfacial tension does not change on the water-repellent film where the electrode is not located below, the liquid does not spread outside the range 52 where the electrode is present no matter how high the voltage is. Therefore, it is possible to accurately control the minimum distance between the two structures. In FIG. 5, 101 is the first structure, 102 is the second structure, 111 is the base material of the first structure, 112 is the base material of the second structure, 103 is the liquid, 21 is the filling liquid, 107 is First water repellent film, 108 is a second water repellent film, 53 and 106 are insulating films, 31 is a hydrophilic region, 51 is a first electrode, 109 is a second electrode, and 110 is between the first electrode and the second electrode. A means for applying a voltage. 52 is an arrow which shows the range where the electrowetting phenomenon occurs.

(Position moving mechanism 6)
In a more preferred position movement mechanism of the present invention, two or more liquids are arranged in the position movement mechanisms 1 to 5.

  FIG. 6 is a schematic diagram showing an example of the position movement mechanism of the present invention. Compared with the case where there is only one liquid, the tilt angles of the structures 1 and 2 can be kept stable. In FIG. 6, 601 is the first structure, 602 is the second structure, 603 is the base material of the second structure, 604 is the base material of the first structure, 605 is the liquid, 606 is the liquid for filling, and 607 is First water repellent film, 613 is a second water repellent film, 608 and 609 are insulating films, 610 is a hydrophilic region, 614 is a first electrode, 611 is a second electrode, 612 is between the first electrode and the second electrode A means for applying a voltage.

(Position moving mechanism 7)
A more preferred position moving mechanism of the present invention includes a means for allowing the position moving mechanism 6 to set the value of the voltage to be applied independently for each liquid.

  FIG. 16 is a schematic diagram showing an example of the position movement mechanism of the present invention. Since voltage can be applied to each liquid independently by means 1 (615) and means 2 (616) for applying voltage, the inclination of the surface facing the distance between the first structure 601 and the second structure 602 can be adjusted. It becomes possible. For example, if a voltage is applied only to the left liquid by the voltage applying means 1, the distance between the left side of the first structure and the second structure in the figure is reduced, so that the inclination of both structures changes. FIG. 16 shows a case where two liquids are arranged, but if the liquid is added to the front and back of the paper, the angles of the opposing surfaces of the first structure and the second structure can be freely changed. It becomes possible.

  Moreover, the small camera of this invention adjusts the distance of an image pick-up element and a lens with the position moving mechanism of the moving mechanisms 1-7.

Moreover, the goniometer of this invention adjusts the inclination of a surface with the moving mechanism of 1-7.
The fiberscope of the present invention has a structure in which a small camera is installed at one end of the fiber and the captured video signal is transmitted to the other end of the fiber. It adjusts with the goniometer using the moving mechanisms 1-7.

  Hereinafter, in order to facilitate understanding of the present invention, an embodiment of the present invention will be described. However, the present invention is not limited to only those listed in this embodiment.

(Embodiment 1)
FIG. 12 is a schematic diagram of the position movement mechanism of the present invention. A cross-sectional view of the vicinity of the first structure 101, the liquid 103, and the second structure 102 is shown in FIG. In the present embodiment, the first structure is a part of the bottom surface of the fixed cylinder 404. The second structure 102 can move up and down in the cylinder. It is assumed that gravity works downward in the paper. Therefore, in the figure, the binding force 104 acting on the second structure is gravity.

  The fixed cylinder 404 has an inner diameter of 10 mm and a height of 30 mm, and is made of polycarbonate resin. The first structure 101 is a silicon substrate 111 having a thickness of 100 μm (see FIG. 1; included in part of the first structure 101 in FIG. 12), and a platinum electrode 105 having a thickness of 100 nm (the first electrode in FIG. 1). , Lead zirconate titanate 106 having a thickness of 100 nm (hereinafter referred to as PZT; insulating film in FIG. 1) and water repellent film 107 having a thickness of about 1 nm (first water repellent film in FIG. 1). It is fixed to. The second structural body 102 is a disc having a thickness of 100 μm, and a platinum electrode 109 (second electrode in FIG. 1) having a diameter of 1 mm is formed at the center. A second water repellent film 108 that is the same as the structure is formed. In the gap between the first structure and the second structure, 600 μl of 1 mM KCl aqueous solution (liquid in FIG. 1) is inserted. The solution is located at the center of the second structure and is in contact with the second electrode. A DC voltage can be applied to the first electrode and the second electrode. In the position movement mechanism of the present embodiment, the second structure is designed to approach 500 μm by applying DC 5V.

A method for manufacturing the first structure and the second structure will be described below.
(1) Manufacturing method of 1st structure After forming the 1st electrode by the vacuum sputtering method on the silicon substrate, PZT was continuously formed by the vacuum sputtering method. The prepared PZT surface was irradiated with UV light for 10 minutes in an ozone atmosphere at 110 ° C. Thereafter, the substrate was immersed in a mixed solvent of n-hexadecane and chloroform (4: 1 by volume) in which 1 vol% of CF ₃ (CF ₂ ) ₇ C ₂ H ₄ SiCl ₃ was dissolved. Washed with chloroform. These immersion and cleaning operations were performed in a nitrogen atmosphere. Thereafter, the substrate was washed with water. As a result, a water-repellent monomolecular film having a thickness of 1 nm or less was formed on PZT.
(2) Production Method of Second Structure A second electrode was produced on a polycarbonate substrate having a thickness of 100 μm by a vacuum sputtering method using a metal mask. Thereafter, the substrate surface on which the electrodes were formed was irradiated with UV light for 10 minutes in an atmosphere of ozone at room temperature. Thereafter, the substrate was immersed in an n-perfluorooctane solvent in which 1 vol% of CF ₃ (CF ₂ ) ₇ C ₂ H ₄ SiCl ₃ was dissolved, and then the substrate was washed with n-perfluorooctane. These immersion and cleaning operations were performed in a nitrogen atmosphere. Thereafter, the substrate was washed with water. Next, a metal mask was brought into close contact with the substrate surface on which the electrode was formed, and oxygen plasma was irradiated only on the electrode portion to remove the water-repellent monomolecular film on the electrode. As a result, a second structure in which a water-repellent monomolecular film having a thickness of 1 nm or less was formed other than on the second electrode.

  When a 1 mM KCl aqueous solution was dropped as a liquid, the static contact angle θ with respect to the second water repellent film was 120 degrees.

  Since the PZT thin film used in this example has a dielectric constant as high as 700, the capacitor-capacitance C increases in equation (3), and a large electrowetting phenomenon can be obtained even when a low voltage is applied. Furthermore, since the monomolecular film used in this example has a film thickness as small as 1 nm or less, the capacitance C in equation (3) increases and a large electrowetting phenomenon can be obtained even when a low voltage is applied. In addition, since the monomolecular film of this example has a siloxane bond (Si—O) with the PZT surface, the film does not peel off, and a highly durable position movement mechanism can be realized.

  In this embodiment, PZT is used as the insulating film. However, the present invention is not limited to this. As the insulating film to be used, a ferroelectric material having a large dielectric constant is desirable in order to increase the capacitance C in the equation (3). Examples of the ferroelectric include PZT added with magnesium, manganese, cobalt, iron, nickel, niobium, scandium, tantalum, bismuth, tantalum, and the like. Also useful are barium strontium titanate compounds.

Further, the water repellent film is not limited to a monomolecular film, and a fluororesin such as polytetrafluoroethylene may be used. Alternatively, a water repellent film can be formed by applying a mixed solution of CF ₃ (CF ₂ ) ₇ C ₂ H ₄ Si (OCH ₃ ) ₃ , alcohol, water, and an acidic catalyst. In addition, a water-repellent film can be formed by applying a mixed solution of Si (OC ₂ H ₅ ) ₄ , CF ₃ (CF ₂ ) ₇ C ₂ H ₄ Si (OCH ₃ ) ₃ , alcohol, water, and an acidic catalyst, followed by baking. It is possible to form.

  In this embodiment, a 1 mM KCl aqueous solution is used as the liquid. However, the present invention is not limited to this, and another aqueous solution, an organic solvent, or a mixture of an aqueous solution and an organic solvent may be used. In particular, in order to greatly change the interfacial tension between the liquid and the insulating film at a low voltage, it is necessary to generate a large amount of electric charge at the interface between the liquid and the insulating film. Therefore, it is preferable that the liquid used is an electrolytic solution.

Examples of the water-soluble electrolyte include an aqueous NaCl solution, an aqueous NaBr solution, an aqueous NH ₄ Cl solution, and buffer solutions containing various salts. In the case of an electrolytic solution using an organic solvent, acetic anhydride, methanol, tetrahydrofuran, propylene carbonate, nitromethane, acetonitrile, dimethylformamide, dimethyl sulfoxide, hexamethylphosphoamide can be used as the solvent, and NaClO ₄ , LiClO can be used as the electrolyte. ₄ , KOH, KOCH ₃ , NaOCH ₃ , LiCl, NH ₄ Cl, n- (CH ₃ C ₃ H ₆ ) ₄ Ni, Mg (ClO ₄ ) ₂ , NaBF _{4 and the} like can be used. In addition, alcohol solvents, various esters, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons and other various oils containing a trace amount of water-soluble electrolyte can also be used. A preferable abundance of the salt or the electrolyte is in the range of 10 ⁻⁴ mass% to 30 mass%.

(Embodiment 2)
FIG. 13 is a schematic diagram of the position movement mechanism of the present invention. FIG. 2 is a cross-sectional view of the vicinity of the first structure 101, the liquid 103, and the second structure 102. The basic structure of the present invention is the same as that of the first embodiment, but a filling liquid 21 is newly added. Reference numeral 1001 denotes a fixed cylinder. In this embodiment, an organically modified silicone oil (manufactured by Gelest, phenylmethylsiloxane homopolymer) having a specific gravity of 1.0 and a viscosity of 10 cPs (centipoise) was used as the filling liquid. The amount of the filling liquid was adjusted so that the liquid 103 was completely contained therein, no bubbles were contained therein, and the liquid did not protrude from the gap between the first structure and the second structure. The surface tension of the filling liquid was about 30 dyne / cm, and the liquid level when filled was concave. For this reason, a filling liquid becomes a negative pressure compared with an external pressure, and an attractive force comes to work between a 1st structure and a 2nd structure. This attractive force is a force that binds the first structure and the second structure.

  When the binding force is gravity, if the fixed cylinder is tilted or turned upside down, the liquid sandwiched between the two structures will move away from both structures and will not operate as a position movement mechanism, but the surface tension of the filling liquid Is a binding force, the filling liquid is in contact with both structures regardless of the inclination of the fixed cylinder, and can operate as a position movement mechanism.

  In this embodiment, silicone oil having a specific gravity close to water is used as the filling liquid, so that the position of the liquid 103 is not shifted by buoyancy.

  The filling liquid need not be limited to silicone oil, and for example, fluorine oil may be used. When the liquid 103 is an aqueous solution, the fluorine-based oil has no affinity for water more than that of silicone, so the liquid does not dissolve in the filling liquid even after a long time, and there is a position movement mechanism that can withstand long-time use. realizable.

(Embodiment 3)
A position movement mechanism similar to that of the second embodiment was formed. However, there is a hydrophilic region in which the water repellent film is not formed on the insulator of the first structure, and the liquid is in contact with the hydrophilic region. FIG. 3 shows a cross-sectional view of the first structure, the liquid, and the vicinity of the second structure according to the present embodiment. A circular hydrophilic region 31 having a diameter of 1 mm is formed at the center of the first structure 101. This hydrophilic region was formed by forming a water repellent film and then bringing a metal mask with a circular hole having a diameter of 1 mm into close contact with the water repellent film and irradiating the metal mask with oxygen plasma. That is, oxygen plasma hits only the water repellent film in the perforated part and the water repellent film was removed, and at the same time, the PZT was hydrophilized.

  Since the liquid is in contact with the hydrophilic region, the liquid does not deviate from the position centered on the hydrophilic region, so that the positional relationship between the first structure and the second structure does not deviate.

(Embodiment 4)
A position movement mechanism similar to that of Embodiment 3 was produced. However, the hydrophilic region has a concave shape. FIG. 4 shows a cross-sectional view of the first structure, the liquid, and the vicinity of the second structure. The hydrophilic region 41 has a circular shape with a bottom of 1 mm in diameter and a concave shape with a depth of 80 nm. Before forming the water-repellent film, the recess was perforated by a photolithography method in the PZT film. A mixed aqueous solution of hydrofluoric acid and nitric acid was used as the etchant for the PZT film. Thereafter, in the same manner as in Embodiment 3, after forming the water repellent film, the water repellent film having only the recesses was removed by oxygen plasma treatment.

  In the present embodiment, the contact area of the liquid is increased as compared with the case where the hydrophilic region is flat, and the liquid is less likely to be separated from the hydrophilic region. Therefore, even if the position movement operation is repeated, the center position of the liquid is always in the hydrophilic region and does not shift, and the positional relationship between the first structure and the second structure can be accurately maintained.

(Embodiment 5)
A position movement mechanism was produced in the same manner as in the third embodiment. However, in the first structure, the area of the first electrode was smaller than the area of the water repellent film, and the liquid was positioned directly above the electrode. FIG. 5 shows a cross-sectional view of the first structure, the liquid, and the vicinity of the second structure.

  The shape of the first electrode 51 was a circle having a diameter of 5 mm. At the center is a hydrophilic region 31. When a voltage is applied between the first electrode and the second electrode, the voltage spreads due to the liquid electrowetting phenomenon on the water-repellent film above the electrode. However, since the interfacial tension does not change on the water-repellent film having no electrode, the liquid does not spread outside the range 52 where the electrode is present no matter how high the voltage is. Therefore, it is possible to accurately control the minimum distance between the two structures.

(Embodiment 6)
FIG. 14A shows a schematic diagram of the present embodiment. FIG. 14B is a plan view of the first structure 601 as viewed from above, and schematically shows the arrangement of the liquid 605 on the first water-repellent film 607. FIG. 6 is a cross-sectional view of the vicinity of the first structure, the liquid, and the second structure. The basic structure of the present invention is the same as that of the fifth embodiment, except that a large number of liquids 605 are arranged. Compared to the case where there is one liquid, when there are a large number of liquids as in this embodiment, the tilt angles of the two structures can be kept stable.

  A large number of liquids 605 having a volume of 0.5 μl are arranged on the first water-repellent film so that the center distance of the liquid is 2 mm. However, the liquid falls within a range of 2 mm from the periphery of the first structure (inside the dotted line 615 in the figure). In addition, the contact area | region with the 1st water repellent film | membrane of the arrange | positioned liquid was an in-circle area | region with a diameter of 0.2 mm in the state which does not apply a voltage. Further, as shown in FIG. 6, the central portion 610 of the liquid is a hydrophilic region. The hydrophilic region was a circular inner region having a diameter of 50 μm. Further, a circular first electrode 614 having a diameter of 1 mm was formed under each hydrophilic region. The second electrode 611 of the second structure 602 is positioned directly above the first electrode 614, and the shape is a circle with a diameter of 50 μm.

  This position movement mechanism is designed so that the distance between the first structure and the second structure approaches 100 μm when a voltage of DC 5 V is applied between the first electrode and the second electrode.

(Embodiment 7)
A schematic diagram of the small camera of this embodiment is shown in FIG. An imaging element 1003 is fixed to the second structure body 602 of the position movement mechanism described in Embodiment 6. An objective lens 1002 is installed above the image sensor. The object to be imaged forms an image on the image sensor 1003 through the objective lens 1002. The image is focused by adjusting the distance between the image sensor 1003 and the objective lens 1002 by moving the second structure 602 up and down. As in the sixth embodiment, when a voltage of DC 5V is applied between the first electrode and the second electrode, the distance between the first structure and the second structure can move by 100 μm.

(Embodiment 8)
The goniometer of the present embodiment includes a mechanism capable of independently controlling the voltage applied to each liquid in the sixth embodiment. The basic structure is the same as that of FIG. 14, but a mechanism for applying a voltage to each liquid independently is provided. The second structure 602 is designed so that the outer diameter of the second structure 602 is 1 mm smaller than the inner diameter of the fixed cylinder, so that the second structure can freely tilt in the cylinder.

(Embodiment 9)
A schematic view of the entire fiberscope of the present embodiment is shown in FIG. 17A. In the fiberscope of the present invention, a small camera is attached to one end 162 of a flexible elongated cylindrical fiberscope 161, and the other end 163 has a mechanism for taking out image information captured by the small camera through the fiber. (A mechanism for taking out is not shown). FIG. 17B is an enlarged schematic view of a fiberscope end 162 portion where a small camera is installed. The basic structure of this part is the same as that of the eighth embodiment, but the second structure 164 is different in that a small camera having an image sensor and a lens is fixed (details of the camera structure are shown in FIG. Not shown). This camera uses a lens with a deep depth of focus, eliminating the need for focusing. Therefore, the image quality of the object photographed with this camera is inferior to that of the seventh embodiment, but the request can be sufficiently satisfied depending on the object to be photographed and the photographing purpose. As shown in FIG. 17B, in this camera, since the voltage of each liquid 605 can be independently applied to freely adjust the inclination of the second structure 164, the orientation of the camera can be adjusted according to the position of the object to be photographed. Can be combined. 21 is a filling liquid, 101 is a first structure, and 1001 is a fixed cylinder.

[Industrial applicability]
If the position moving mechanism of the present invention is used, the position can be easily reduced and the position can be moved with low power. Therefore, the position moving mechanism can be used as a position moving mechanism of a medical micromachine. For example, it can also be used for a surgical actuator installed at the tip of a stomach camera or colon camera.

The schematic diagram which shows the cross section of the position movement mechanism in one Embodiment of this invention. The schematic diagram which shows the cross section of the position movement mechanism in one Embodiment of this invention. The schematic diagram which shows the cross section of the position movement mechanism in one Embodiment of this invention. The schematic diagram which shows the cross section of the position movement mechanism in one Embodiment of this invention. The schematic diagram which shows the cross section of the position movement mechanism in one Embodiment of this invention. The schematic diagram which shows the cross section of the position movement mechanism in one Embodiment of this invention. FIG. 2 is a schematic diagram showing a state of liquid dropped on the water-repellent film in one embodiment of the present invention, A is a schematic diagram showing a state of liquid dropped on the water-repellent film, and B is an electrowetting phenomenon. The schematic diagram which showed the state of the liquid from which the shape changed according to. It is the schematic diagram which showed the state of the liquid in one Embodiment of this invention, A is a schematic diagram of the convex-shaped liquid pinched | interposed into two flat plates, B is the liquid which the shape changed by the electrowetting phenomenon Schematic diagram of two flat plates sandwiched between. The schematic diagram of two flat plates pinched | interposed into the concave-shaped liquid in one Embodiment of this invention. It is a schematic diagram of two flat plates sandwiched between liquids in an embodiment of the present invention, and shows an example in which the positions of liquids are different between A and B. It is a schematic diagram of the liquid which contacted simultaneously the water-repellent and hydrophilic area | region in one Embodiment of this invention, A shows an initial state, B shows a state with stable energy. The schematic diagram which shows the position moving mechanism in one Embodiment of this invention. The schematic diagram which shows the position moving mechanism in one Embodiment of this invention. It is a schematic diagram which shows the position movement mechanism in one Embodiment of this invention, A is a schematic diagram which shows the position movement mechanism of this invention, B shows the top view which looked at the 1st structure from the upper part, and arrangement | positioning of a liquid. The schematic diagram which shows the camera of one Embodiment of this invention. The schematic diagram which shows the cross section of the position movement mechanism in one Embodiment of this invention. A is a schematic view of the entire fiberscope in one embodiment of the present embodiment, and B is an enlarged schematic view of a fiber end portion where a small camera is installed.

Explanation of symbols

101,601,201,601 First structure
102,602,202,602 second structure
103,605,701,710,301 Liquid
104 Binding power
51,105,614 1st electrode
106,608,703, 609, 53 Insulating film
107,607 1st water repellent film
108,613 2nd water repellent film
109,611 Second electrode
110,612 Means for applying voltage between first electrode and second electrode
111,604 Part of first structure
112,603 Part of second structure
113 Static contact angle between liquid and second water repellent film
21,606 Filling liquid
22 Shape of filling liquid
31,303,610 Hydrophilic region
41 Concave area
52 Arrow indicating the range of electrowetting phenomenon
615 Line indicating the area where the liquid is placed
702 Water repellent film
704 electrodes
705 Contact angle when no voltage is applied
706,712 Droplet height
707 Vector indicating surface tension of liquid
708 Vector indicating surface energy of water repellent film
709 Vector showing interfacial tension between liquid and water repellent film
711 Contact angle of liquid when voltage is applied
713 Interfacial tension during voltage application
714 platinum wire
715 Voltage application means
91,802 Upper plate
92,803 Lower plate
93,801,203 Liquid sandwiched between two flat plates
94 Concave shape
95,96,805,806,810,811 Contact area between plate and liquid
97,98 The attractive force that the plate receives from the liquid
804,813 Convex shape
807,812 Distance between two flat plates
808,809,814,815 Drag received from liquid by plate
204 Misaligned liquid
302 Water repellent area
304 Liquid centered on hydrophilic region
404,1001 fixed cylinder
1002 Objective lens
1003 Image sensor

Claims (23)

  A liquid is disposed between the first structure and the second structure, and by applying a voltage to the liquid, the shape of the liquid is changed by an electrowetting phenomenon, and the first structure and the second structure are changed. A moving mechanism that adjusts the spacing between structures.   The surface of the first structure in contact with the liquid includes a first electrode, an insulating film formed on the first electrode, and a first water repellent film formed on the insulating film. 2. The moving mechanism according to 1.   A second electrode having a second water-repellent film formed in the periphery is formed on the surface of the second structure that is in contact with the liquid, and the liquid is applied to both the second electrode and the second water-repellent film. The moving mechanism according to claim 1, which is in contact.   The moving mechanism according to claim 1, further comprising a binding force that prevents the first structure and the second structure from being separated from each other by surface tension of the liquid between the first structure and the second structure.   The moving mechanism according to claim 3, wherein a static contact angle θ of the liquid with respect to the second water-repellent film is greater than 90 degrees.   A filling liquid that does not mix with the liquid is filled between the first structure and the second structure, and is in contact with the first structure, the second structure, and the liquid of the filling liquid. The moving mechanism according to claim 1, wherein a liquid surface shape in a portion that is not formed is a concave shape.   The moving mechanism according to claim 2, wherein a hydrophilic region in which a water repellent film is not formed is provided on the insulator of the first structure, and the liquid is in contact with the hydrophilic region.   The movement mechanism according to claim 7, wherein the hydrophilic region has a concave shape.   The moving mechanism according to claim 2, wherein in the first structure, the area of the first electrode is smaller than the area of the water-repellent film, and the liquid is located immediately above the electrode.   The moving mechanism according to claim 1, wherein two or more liquids are arranged.   The moving mechanism according to claim 10, further comprising means for independently setting a value of a voltage applied to the liquid for each liquid.   The moving mechanism according to claim 10, further comprising a frame around the first structure and the second structure. A liquid is disposed in a gap between the first structure and the second structure, and both the first structure and the second structure are in contact with the liquid;
The surface of the first structure in contact with the liquid includes a first electrode, an insulating film formed on the first electrode, and a first water repellent film formed on the insulating film,
A second electrode having a second water-repellent film formed in the periphery is formed on the surface of the second structure that is in contact with the liquid,
The liquid is in contact with both the second electrode and the second water repellent film;
A moving mechanism comprising means for applying a voltage between the first electrode and the second electrode.   The moving mechanism according to claim 13, wherein a static contact angle θ of the liquid with respect to the second water-repellent film is greater than 90 degrees.   A filling liquid that does not mix with the liquid is filled between the first structure and the second structure, and is in contact with the first structure, the second structure, and the liquid of the filling liquid. The moving mechanism according to claim 1, wherein a liquid surface shape in a portion that is not formed is a concave shape.   The moving mechanism according to claim 13, wherein a hydrophilic region in which a water repellent film is not formed is provided on the insulator of the first structure, and a liquid is in contact with the hydrophilic region.   The movement mechanism according to claim 16, wherein the hydrophilic region has a concave shape.   The moving mechanism according to claim 13, wherein in the first structure, the area of the first electrode is smaller than the area of the water repellent film, and the liquid is located immediately above the electrode.   The moving mechanism according to claim 13, wherein two or more liquids are arranged.   The moving mechanism according to claim 19, further comprising means capable of independently setting a value of a voltage applied to the liquid for each liquid.   A liquid is disposed between the first structure and the second structure, and by applying a voltage to the liquid, the shape of the liquid is changed by an electrowetting phenomenon, so that the first structure and the second structure are changed. A camera characterized in that a distance between an imaging element and a lens is adjusted by a moving mechanism that adjusts a distance between structures.   A liquid is disposed between the first structure and the second structure, and by applying a voltage to the liquid, the shape of the liquid is changed by an electrowetting phenomenon, so that the first structure and the second structure are changed. A goniometer characterized by using a moving mechanism for adjusting the interval between structures.   A liquid is disposed between the first structure and the second structure, and by applying a voltage to the liquid, the shape of the liquid is changed by an electrowetting phenomenon, so that the first structure and the second structure are changed. A fiberscope that adjusts the orientation of an image sensor by a moving mechanism that adjusts the interval between structures.

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