JP4696943B2 - Optical element - Google Patents

Description

  The present invention relates to an optical element.

There has been proposed an optical element that changes an optical characteristic by changing an interface shape between the first and second liquids using an electrocapillary phenomenon (electrowetting phenomenon).
Such an optical element has first and second end face walls facing each other and a side wall connecting the first and second end face walls, and a sealed storage chamber is formed inside them. Equipped with a container.
Then, the first liquid having polarity or conductivity and the second liquid sealed in the storage chamber and not mixed with the first liquid are sealed in the storage chamber, and an electric field is applied to the first liquid. The interface shape between the first and second liquids is changed by providing a first electrode and a second electrode, and applying a voltage between the first electrode and the second electrode.
By the way, when such an optical element constitutes a diaphragm, when the aperture of the diaphragm is decentered, and when the optical element constitutes a lens, when the lens is decentered, the optical characteristics of the optical element Adversely affects.
In order to prevent the occurrence of such eccentricity, one of the first electrode and the second electrode of the optical element is divided into a plurality of electrode portions, and the voltage applied to each electrode portion is determined according to the amount of eccentricity. Techniques for controlling each have been proposed (see Patent Document 1).
JP 2003-177219 A

However, the above-described conventional technology requires a control circuit that applies different voltages to the plurality of electrode portions in accordance with the eccentricity of the optical element, so that the optical element can be simplified and reduced in cost. In addition, since the voltage applying means must apply different voltages to the respective electrode portions, it is disadvantageous in terms of reducing power consumption during operation of the voltage applying means.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide an optical element that is advantageous in terms of simplification, cost reduction, and power consumption of the optical element while preventing the occurrence of eccentricity. There is to do.

In order to achieve the above-mentioned object, the present invention has first and second end face walls facing each other and a side wall connecting the first and second end face walls, and is sealed inside them. A container in which the storage chamber is formed, a polar or conductive first liquid sealed in the storage chamber, and a second liquid sealed in the storage chamber and not mixed with the first liquid A first electrode and a second electrode for applying an electric field to the first liquid, and a voltage applying means for applying a voltage between the first electrode and the second electrode. The transmittance of the liquid is formed to be lower than the transmittance of the second liquid, and the interface between the first liquid and the second liquid is deformed by the voltage application by the voltage applying means, and the first and second liquids are deformed. The first and second end face walls face each other through the end face wall and the second liquid portion. The optical element is formed with a light transmission path extending in the thickness direction of the container, and the first electrode is formed on an inner surface of the first end face wall facing the storage chamber. The second electrode is formed on the inner surface of the second end face wall facing the storage chamber, and the second electrode is centered on a single virtual axis extending in the thickness direction of the container. A plurality of electrode portions extending in a radial direction are formed, and a first non-electrode portion where the electrode portions are not formed is formed between the electrode portions adjacent to each other in the circumferential direction of the virtual axis. The electrode portions and the first non-electrode portions each have a width along the circumferential direction of the imaginary axis, and the width of the electrode portions gradually increases as the electrode portions extend radially outward. Each first non-electrode portion is formed so as to extend outward in the radial direction. Wherein the serial first width of the non-electrode portion is formed so as to gradually increase.
In addition, the present invention includes first and second end face walls facing each other and a side wall connecting the first and second end face walls, and a sealed storage chamber is formed therein. A transparent first liquid having polarity or conductivity sealed in the storage chamber, a transparent second liquid sealed in the storage chamber and not mixed with the first liquid, A first electrode and a second electrode for applying an electric field to the first liquid; and a voltage applying means for applying a voltage between the first electrode and the second electrode. By applying voltage, the interface shape of the first liquid and the second liquid is deformed into a curved surface, so that the first and second end face walls proceed in the thickness direction of the container, which is a direction facing each other. An optical element that refracts light passing through the interface, Is formed on the inner surface of the first end surface wall facing the storage chamber, the second electrode is formed on the inner surface of the second end surface wall facing the storage chamber, and the second electrode is Consists of a plurality of electrode portions extending radially about a single virtual axis extending in the thickness direction of the container, and the electrodes between the electrode portions adjacent in the circumferential direction of the virtual axis 1st non-electrode part in which a part is not formed is formed, and each said electrode part and each said 1st non-electrode part have a width along the circumferential direction of said virtual axis, respectively, and each said electrode part Is formed such that the width of the electrode portion gradually increases toward the outer side in the radial direction, and each of the first non-electrode portions has a width of the first non-electrode portion toward the outer side in the radial direction. The width is formed so as to gradually increase.

According to the optical element of the present invention, although the same voltage is applied to each electrode portion, the first liquid and the second liquid are positioned at a position where the center of the second liquid coincides with the virtual axis. Since the shape of the liquid interface is stable, the optical element is prevented from being decentered.
Therefore, it goes without saying that it is advantageous in preventing the optical characteristics of the optical element from degrading, and unlike the conventional optical element, the voltages applied to the plurality of electrode portions differ depending on the eccentricity of the light transmission path. This eliminates the need for a control circuit to be applied, which is advantageous for simplifying and reducing the cost of the optical element, and also for reducing power consumption.

First, the principle of the electrocapillary phenomenon (electrowetting phenomenon) used by the optical element of the present invention will be described.
9A and 9B are diagrams illustrating the principle of the electrocapillary phenomenon. FIG. 9A is a diagram illustrating a state before voltage application, and FIG. 9B is a diagram illustrating a state after voltage application.
As shown in FIG. 9A, an insulating film 2 is formed on the surface of the substrate 1, and a polar or conductive first liquid 3 is located on the surface of the insulating film 2, and the first The first electrode 4 is electrically connected to the liquid 3.
A second electrode 5 is formed between the insulating film 2 and the substrate 1.
As shown in FIG. 9A, when the voltage E is not applied between the first electrode 4 and the second electrode 5, the surface of the first liquid 4 protrudes upward due to surface tension. It is almost spherical. At this time, the angle θ between the surface of the insulating film 2 and the portion where the first liquid 3 is in contact with the insulating film 2, that is, the contact angle θ is defined as θ 0. The contact angle θ is measured with the liquid facing the air, in other words, measured at the gas-liquid interface.
However, as shown in FIG. 9B, when an electric field is applied to the first liquid 4 by applying a voltage E between the first electrode 4 and the second electrode 5, the insulating film 2. An electric field (electrostatic force) acts on the molecules constituting the first liquid 3 by, for example, charging a negative charge on the surface of the first liquid 3. As a result, the molecules constituting the first liquid 3 are attracted, so that the wettability of the first liquid 3 with respect to the insulating film 2 is improved, and the contact angle θ becomes θ1 smaller than θ0. Further, the contact angle θ decreases as the value of the voltage E increases.
Such a phenomenon is called an electrocapillary phenomenon.

Next, the optical element 10 of the present embodiment will be described.
In the present embodiment, the optical element 10 forms a diaphragm.
FIG. 1 is a longitudinal sectional view showing the configuration of the optical element 10, and FIG. 2 is a view taken along the line AA in FIG.
As shown in FIG. 1, the optical element 10 includes a container 12, a first liquid 14, a second liquid 16, a first electrode 18, a second electrode 20, and a voltage applying unit 22. It is configured to include.
The container 12 includes a first end surface wall 24 and a second end surface wall 26 which face each other and extend in parallel, and a side wall 28 which connects the first and second end surface walls 24 and 26. The housing chamber 30 is hermetically sealed by the first and second end face walls 24 and 26 and the side wall 28.
Here, the thickness direction of the container 12 refers to a direction in which the first end face wall 24 and the second end face wall 26 face each other.
In the present embodiment, the first and second end face walls 24 and 26 have a rectangular plate shape having the same shape and the same size, and the side wall 28 has an outline of the first and second end face walls 24 and 26. The container 30 has a flat rectangular column shape.
The first and second end face walls 24 and 26 and the side wall 28 are made of an insulating material, and the first and second end face walls 24 and 26 are made of a transparent material that transmits light. Is formed.
As a material constituting the first and second end face walls 24 and 26, for example, a transparent and insulating synthetic resin material or a transparent glass material can be used.

The first liquid 14 has polarity or conductivity and is enclosed in the storage chamber 30.
The second liquid 16 is not mixed with the first liquid 14 and is enclosed in the storage chamber 30.
Further, the first liquid 14 and the second liquid 16 have substantially the same specific gravity, and the transmittance of the first liquid 14 is formed to be lower than the transmittance of the second liquid 16. .
In the present embodiment, the first liquid 14 is formed, for example, by mixing fine particles made of a material that does not transmit light with a liquid obtained by mixing pure water, ethanol, and ethylene glycol.
As the fine particles, for example, carbon black can be used. When carbon black is used, it is preferable to perform hydrophilic coating treatment on the surfaces of the carbon black so that the carbon black is uniformly mixed with the first liquid 14. The hydrophilic coating treatment is performed, for example, by forming a hydrophilic group on the surface of carbon black.
In the present embodiment, the second liquid 16 is composed of silicon oil.
The liquid that can be used as the first liquid 14 is not limited to the present embodiment. For example, nitromethane, acetic anhydride, methyl acetate, ethyl acetate, methanol, acetonitrile, acetone, ethanol, propionitrile. , Tetrohydrofuran, n-hexane, 2-propanol, 2-butanone, n-butyronitrile, 1-propanol, 1-butanol, dimethyl sulfoxide, chlorobenzene, ethylene glycol, formamide, nitrobenzene, propylene carbonate, 1,2-dichloroethane, Carbon disulfide, chloroform, bromobenzene, carbon tetrachloride, trichloroacetic anhydride, toluene, benzene, ethylenediamine, N, N-dimethylacetamide, N, N-dimethylformamide, tributyl phosphate, pyridine, benzene Nitoru, aniline, 1,4-dioxane, hexamethylphosphoramide and the like.
Examples of the liquid that can be used as the second liquid 16 include silicon, decane-based, octane-based, nonane, and heptane.
The first liquid 14 and the second liquid 16 may be formed of a single liquid, or may be formed by mixing a plurality of liquids. In short, it is sufficient that the first liquid 14 and the second liquid 16 are formed so as to have substantially the same specific gravity.

The first and second electrodes 18 and 20 are for applying an electric field to the first liquid 14.
The first electrode 18 is formed at a location where the first end wall 24 faces the storage chamber 30, and in the present embodiment, the first end wall 24 is formed over the entire inner surface facing the storage chamber 30.
More specifically, in this embodiment, as will be described later, the hydrophilic film 34 is used to increase the operating speed of the diaphragm, and the first electrode 18 faces the first liquid 14. The first electrode 18 is disposed so as to face the first liquid 14 through the hydrophilic film 34.
The second electrode 20 is formed on a part of the inner surface of the second end face wall 26 facing the accommodation chamber 30.
The first and second electrodes 18 and 20 are made of a conductive material such as an ITO film (Indium Tin Oxide film) that can transmit light.
The voltage application means 22 is provided outside the container 12, and the output voltage is variable. The positive voltage output terminal of the voltage application means 22 is electrically connected to the first electrode 18, and the voltage application means 22 outputs a negative voltage. A terminal is electrically connected to the second electrode 20.
In this embodiment, the case where the electrocapillarity is generated by applying a DC voltage to the first liquid 14 will be described. However, the voltage applied to the first liquid 14 is limited to the DC voltage. Instead, any voltage such as an AC voltage, a pulse voltage, or a voltage that increases or decreases in a stepwise manner may be used. In short, it is only necessary that the first liquid 14 can generate an electrocapillary phenomenon.

An insulating film 32 is formed on the inner surface of the second end face wall 26 facing the storage chamber 30 and the second electrode 20 provided on the inner surface.
Accordingly, when a voltage is applied to the first electrode 18 and the second electrode 20, for example, a negative charge is charged on the surface of the insulating film 32, whereby an electric field is applied to the first liquid 14, and the first liquid. 14 is configured such that an electric field (electrostatic force) acts on the molecules constituting 14 to generate an electrocapillary phenomenon.

Further, a transparent hydrophilic film 34 (corresponding to the first film in the claims) that transmits light is formed so as to cover the entire area of the first electrode 18 and the entire inner surface of the side wall 28.
The hydrophilic film 34 is configured such that the wettability with respect to the first liquid 14 is higher than the wettability with respect to the second liquid 16. In other words, the contact angle of the first liquid 14 with respect to the hydrophilic film 34 is The contact angle of the second liquid 16 with respect to the hydrophilic film 34 is smaller than the contact angle.
The hydrophilic film 34 can be formed, for example, by applying a hydrophilic polymer or a surfactant to the inner surfaces of the first electrode 18 and the side wall 28, and various conventionally known materials can be employed.
In the present embodiment, a transparent water repellent film 36 that transmits light so as to cover the entire region of the insulating film 32 provided on the second electrode 20 on the second end wall 26 (claims) Corresponding to the second film in the range).
The water repellent film 36 is configured such that the wettability with respect to the second liquid 16 is higher than the wettability with respect to the first liquid 14. In other words, the contact angle of the second liquid 16 with respect to the water repellent film 36 is configured to be smaller than the contact angle of the first liquid 14 with respect to the water repellent film 36.
The water repellent film 36 is an oleophilic film, and can be formed, for example, by baking a material mainly composed of silicon or by forming a material made of an amorphous fluororesin. As the water film 36, various conventionally known materials can be used.

Next, the second electrode 20 will be described in detail.
As shown in FIGS. 1 and 2, the second electrode 20 has a radial direction around a single virtual axis 38 extending in the thickness direction of the container 12 in a plane orthogonal to the thickness direction of the container 12. In the present embodiment, it is composed of four electrode portions 40.
Each electrode part 40 is electrically connected to the negative voltage output terminal of the voltage applying means 22 by a wiring member (not shown).
A first non-electrode part 42 in which no electrode part 40 is formed is formed between the electrode parts 40 adjacent in the circumferential direction of the virtual axis 38.
Each electrode portion 40 and each first non-electrode portion 42 have a width along the circumferential direction of the imaginary axis 38, and each electrode portion 40 gradually increases in width as the electrode portion 40 goes radially outward. It is formed to be large.
Each first non-electrode portion 42 is formed such that the width of the first non-electrode portion 42 gradually increases as it goes outward in the radial direction.
In the present embodiment, each electrode portion 40 has the same shape and the same size, and extends in a fan shape radially outward with the virtual axis 38 as a center. It extends on a single virtual circle centered on it.
The first non-electrode portions 42 are formed in the same shape and size between the electrode portions 40.
In addition, a second non-electrode portion 44 in which the electrode portion 40 is not formed is provided in a circular range around the virtual axis 38 on the plane, and each electrode portion 40 has a radius of the second non-electrode portion 44. It is provided outside in the direction.
In addition, at the radially outer portion of the outer edge portion of each electrode portion 40, the electrode portion 40 is not formed, and a third non-electrode portion 46 connected to each first non-electrode portion 42 is provided.

Therefore, the entire area of the first liquid 14 located on the inner surface of the first end wall 24 where the first liquid 14 is located is in a state of facing the first electrode 18 through the hydrophilic film 34, and The entire region of the second liquid 16 located on the inner surface of the second end face wall 26 where the second liquid 16 is located faces the second electrode 20 through the water repellent film 36 and the insulating film 32. .
Therefore, the voltage V is applied from the voltage applying means 22 to the first electrode 18 and the second electrode 20, for example, a negative charge is charged on the surface of the insulating film 32, thereby applying an electric field to the first liquid 14, An electric field (electrostatic force) acts on the molecules constituting the first liquid 14 to generate an electrocapillary phenomenon. In addition, the same voltage shall be applied to the several electrode part 40 which comprises the 2nd electrode 20. FIG.

Next, the operation of the optical element 10 will be described.
3A, 3B, and 3C are cross-sectional views for explaining the operation when voltages V1, V2, and V3 are applied to the first and second electrodes 18 and 20 of the optical element 10, respectively. (A), (B), (C) is a top view of FIG. 3 (A), (B), (C).
As shown in FIG. 1, in the state where the voltage V is not applied from the voltage applying means 22 to the first electrode 18 and the second electrode 20, the shape of the interface 48 between the first and second liquids 14 and 16 is the first. It is determined by the balance between the surface tension of the second liquids 14 and 16 and the interfacial tension on the water repellent film 36.
Therefore, the larger the difference between the contact angle of the first liquid 14 with respect to the water repellent film 36 and the contact angle of the second liquid 16, the more flat the second liquid 16 spreads on the water repellent film 36. The shape of the interface 48 between the liquid 14 and the second liquid 16 is a curved surface close to a flat surface.
The first liquid 14 is positioned so as to cover the hydrophilic film 34 on the side wall 28 from the hydrophilic film 34 on the first end wall 24.
Therefore, the first liquid 14 located in an annular portion in the vicinity of the boundary between the side wall 28 and the second end wall 26 in the first liquid 14 directly contacts the water-repellent film 36, but the second liquid 16 Is not in contact with the hydrophilic film 34 on the side wall 28.
Therefore, the annular portion where the first liquid 14 is in contact with the water repellent film 36 faces the second electrode 20 with the water repellent film 36 and the insulating film 32 interposed therebetween without the second liquid 16 interposed. Yes.
At this time, the first liquid 14 extends over the entire region in the direction orthogonal to the light transmission direction, so that the light traveling in the thickness direction of the container 12 is blocked.

Next, as shown in FIG. 3A, when the voltage V1 (> 0) is applied from the voltage applying means 22 to the first electrode 18 and the second electrode 20, the interface 48 is caused by electrocapillarity. The second liquid 16 is deformed so as to have a convex curved surface (spherical surface) toward the first liquid 14, and the center of the interface 48 contacts the first end wall 24 (hydrophilic film 34).
As a result, the first liquid 14 does not exist in the region where the interface 48 is in contact with the first end wall 24 (hydrophilic film 34), and as shown in FIG. A region 50 in which only the second liquid 16 exists is formed, and a light transmission path 52 extending in the thickness direction of the container 12 through the first and second end face walls 24 and 26 is formed by this region 50. Is done. That is, the light transmission path 52 forms the opening 52A, and the diameter of the light transmission path 52 (opening 52A) is the aperture diameter D1 of the diaphragm.
Next, as shown in FIG. 3B, when a voltage V2 (> V1) is applied from the voltage application means 22 to the first electrode 18 and the second electrode 20, a convex curved surface ( The slope of the (spherical) curve is further increased.
Then, as shown in FIG. 4B, the diameter of the region 50 where only the second liquid 16 is formed in the storage chamber 30 is enlarged, and the diameter of the light transmission path 52, that is, the aperture diameter of the diaphragm is increased. The diameter is increased from D1 to D2.
Next, as shown in FIG. 3C, when a voltage V3 (> V2) is applied from the voltage application means 22 to the first electrode 18 and the second electrode 20, a convex curved surface ( The slope of the (spherical) curve is further increased.
Then, as shown in FIG. 4C, the diameter of the region 50 where only the second liquid 16 is formed in the storage chamber 30 is further enlarged, and the diameter of the light transmission path 52, that is, the aperture diameter of the diaphragm. Is expanded to D3 (> D2).
Therefore, by adjusting the voltage applied from the voltage application means 22 to the first electrode 18 and the second electrode 20, the diameter of the region 50 where only the second liquid 16 exists is enlarged and reduced to reduce the aperture. The opening diameter can be adjusted.
3A, 3 </ b> B, and 3 </ b> C, reference signs θ <b> 1, θ <b> 2, and θ <b> 3 indicate contact angles of the first liquid 14, and as the electric field applied to the first liquid 14 increases, the contact becomes larger. The corners are reduced and the wettability of the first liquid 14 is increased.

Although the hydrophilic film 34 and the water repellent film 36 can be omitted, the use of the hydrophilic film 34 and the water repellent film 36 as in the present embodiment has the following advantages.
When a transparent hydrophilic film 34 (corresponding to the first film) that transmits light is formed so as to cover the entire area of the first electrode 18 and the entire inner surface of the side wall 28, the first liquid 14 is hydrophilic. The film 34 gets wet well. Therefore, when the second liquid 16 once contacts the first end face wall 24 and then leaves the first end face wall 24, the second liquid 16 is easily separated from the hydrophilic film 34, and the operation speed of the diaphragm is reduced. Speeding up.
Further, when a transparent water-repellent film 36 that transmits light is formed so as to cover the entire region of the insulating film 32 provided on the second electrode 20 on the second end face wall 26, the water-repellent film Since the liquid level of the first liquid 14 is likely to move smoothly on 36, the operating speed of the diaphragm can be increased.

Next, a change in the shape of the interface 48 between the first liquid 14 and the second liquid 16 will be described in detail.
When the voltage V is applied between the first electrode 18 and the second electrode 20, as shown in FIGS. 3A to 3C, the interface 48 between the first liquid 14 and the second liquid 16. Is the contact angle θ, the contact angle θ is expressed by equation (1).
cosθ (V) = cosθ (V = 0) + ε0 ・ εr ・ V2 / 2γt (1)
Here, cosθ (V) is the contact angle when the applied voltage is V [V], cosθ (V = 0) is the contact angle when no voltage is applied, and ε0 is the dielectric constant of vacuum 8.85 × 10-12 [F / m , Εr is the relative dielectric constant of the insulating film 32, V is the applied voltage [V], t is the thickness [m] of the insulating film 32, and γ is the interfacial tension between the first liquid 14 and the second liquid 16 (or Interfacial energy) [N / m].
That is, the contact angle θ is increased or decreased by the increase or decrease of the voltage V (the wettability of the first liquid 14 is changed), and thereby the force with which the first liquid 14 pushes the second liquid 16 is changed. The shape changes.

In this way, by increasing or decreasing the voltage applied between the first electrode 18 and the second electrode 20 from V1 to V3, the shape of the interface 48 changes and the opening diameter changes from D1 to D3. Regardless of the change in voltage applied between the first electrode 18 and the second electrode 20, the light transmission path 52 (opening 52A) is always kept in a state where its center coincides with the virtual axis 38. Even if the center of the light transmission path 52 is deviated from the virtual axis 38 and is decentered, the center of the light transmission path 52 is automatically restored so as to coincide with the virtual axis 38. This will be described in detail.
FIG. 5 is an explanatory view showing a state where the center of the light transmission path 52 coincides with the virtual axis 38, and FIG. 6 is an explanatory view showing a state where the center of the light transmission path 52 is deviated from the virtual axis 38.
5 and 6, for convenience of explanation, four quadrants are defined on the insulating film 32 orthogonal to the virtual axis 38 by two coordinate axes X and Y orthogonal to the virtual axis 38 and orthogonal to each other. Are described as a first quadrant A, a second quadrant B, a third quadrant C, and a fourth quadrant D.
Each electrode unit 40 is located in each of the first quadrant A, the second quadrant B, the third quadrant C, and the fourth quadrant D.

As shown in FIG. 5, in the state where the light transmission path 52 is not decentered, the areas of the first liquids 14 located on the electrode portions 40 are equal to each other and on the electrode portions 40. The areas of the second liquids 16 that are located are equal to each other. In other words, the length of the interface 48 between the first liquid 14 and the second liquid 16 located on each electrode part 40 is equal to each other.
However, as shown in FIG. 6, for example, when the second liquid 16 moves in the direction of the second quadrant B and the light transmission path 52 is decentered, the second liquid 16 is placed on the electrode section 40 of the second quadrant B. The length of the interface 48 positioned is not equal to the length of the interface 48 positioned on the electrode portion 40 in the fourth quadrant D.
Specifically, the length of the interface 48 located on the electrode part 40 in the second quadrant B is longer than the length of the interface 48 located on the electrode part 40 in the fourth quadrant D. . This is because the electrode portions 40 and the first non-electrode portions 42 that are formed radially around the virtual axis 38 are formed such that the width gradually increases toward the outside in the radial direction of the virtual axis 38. It is.
Therefore, if the voltage applied to each electrode part 40 is the same (if it is the same potential), the force per unit length with which the first liquid 14 pushes the second liquid 16 is the same in each quadrant. Since the length of the interface 48 located on the electrode portion 40 is increased, the force pushing the second liquid 16 increases in proportion to the length of the interface 48, and the force pushing the second liquid 16 is The second quadrant B works larger than the fourth quadrant D.
Therefore, since the length of the interface 48 on the electrode part 40 in the fourth quadrant D is longer than the length of the interface 48 on the electrode part 40 in the second quadrant B, the first quadrant B on the second quadrant B The force with which the liquid 14 pushes the second liquid 16 is greater than the force with which the first liquid 14 in the fourth quadrant D pushes the second liquid 16.
As a result, the second liquid 16 is pushed back until the force with which the first liquid 14 pushes the second liquid 16 is balanced, that is, the length of the interface 48 in the second quadrant B as shown in FIG. And the second liquid 16 is pushed back until the length of the interface 48 in the fourth quadrant D becomes equal. As a result, the center of the second liquid 16 and the virtual axis 48 coincide with each other. At this position, the shape of the interface 48 between the first liquid 14 and the second liquid 16 is stabilized, and the light transmission path 52 is decentered. Is prevented.
In addition, in the electrode part 40 of the 1st quadrant A and the 3rd quadrant C, the effect | action of such eccentricity is achieved by the principle similar to the above-mentioned.

FIG. 7 is an explanatory view showing the position of the interface 48.
As shown in FIGS. 3A, 3B, and 3C, the voltage V applied between the first electrode 18 and the second electrode 20 is increased to V1, V2, and V3. As the force with which the second liquid 16 is pushed by the liquid 14 increases, the shape of the interface 48 changes, and the opening diameters increase to D1, D2, and D3.
Then, the second non-electrode portion 44 is provided in a circular range centered on the virtual axis 38, and each electrode portion 40 is provided outside the second non-electrode portion 44 in the radial direction. As shown in FIG. 7A, when the voltage applied between the first electrode 18 and the second electrode 20 is V1, as shown in FIG. 7, the first liquid 14 positioned on the insulating film 32 and The interface 48 of the second liquid 16 is located at a radially outer portion of the outer edge portion of each electrode portion 40, that is, at a position (a) on the boundary line between each electrode portion 40 and the third non-electrode portion 46. The interface 48 can be restricted from moving further outward in the radial direction, and at the same time, the eccentricity of the light transmission path 52 is prevented.
Here, the opening diameter D1 is the minimum opening diameter Dmin of the optical element 10, as shown in FIG.
Moreover, since the outer edge part of each electrode part 40 in the radial direction extends on a single virtual circle with the virtual axis 38 as the center, as shown in FIG. When the voltage applied between the second electrodes 20 is V3, as shown in FIG. 7, the interface 48 between the first liquid 14 and the second liquid 16 located on the insulating film 32 is formed in each electrode portion. 40 is located at the radially inner position of the inner edge of 40, that is, the position (b) on the boundary line between each electrode portion 40 and the second non-electrode portion 44 so that the interface 48 does not move further inward in the radial direction. At the same time, the eccentricity of the light transmission path 52 is prevented.
Here, the opening diameter D3 is the maximum opening diameter Dmax of the optical element 10, as shown in FIG.

The optical element 10 described above is applied to a photographing optical system of an imaging apparatus such as a digital still camera or a video camera.
FIG. 8 is a configuration diagram illustrating an example in which the optical element 10 is applied to a photographing optical system of an imaging apparatus.
As shown in FIG. 8, the imaging apparatus 100 includes an imaging element 102 such as a CCD that captures a subject image, and a photographing optical system 104 that guides the subject image to the imaging element 102.
On the optical axis L, the photographic optical system 104 has a first lens group 106, a second lens group 108, a third lens group 110, a fourth lens group 112, from the subject toward the image sensor 102, The filter group 114 is arranged in this order.
In this example, the first lens group 106 and the third lens group 110 are provided so as not to move in the optical axis direction, and the second lens group 108 is provided as a zoom lens so as to be movable in the optical axis direction. The fourth lens group 112 is provided as a focus lens so as to be movable in the optical axis direction.
The light beam from the subject guided by the first lens group 106 is converted into a parallel light beam by the second lens group 108 and guided to the third lens group 110, via the fourth lens group 112 and the filter group 114. And converged on the imaging surface 102 of the imaging element 102.
The optical element 10 is disposed between the second lens group 108 and the third lens group 110 where the parallel luminous flux passes with the virtual axis 38 aligned with the optical axis L of the photographing optical system 104. Has been.
Therefore, the light transmission path 52 (opening 52A) of the optical element 10 expands and contracts, whereby the amount of light guided to the imaging surface 102A is increased or decreased.
Strictly speaking, the force of the electric field applied to the first liquid 14 is not uniform in the circumferential direction of the virtual axis 38 because the first non-electrode part 42 is provided between the plurality of electrode parts 40. Therefore, since the interface 48 between the first liquid 14 and the second liquid 16 is not uniform in the circumferential direction of the virtual axis 38, the shape of the light transmission path 52 (opening 52A) of the optical element 10 is also a perfect circle. Rather, the radial dimension varies along the circumferential direction.
However, as described above, since the stop is disposed at a position where the light beams are parallel, the influence of the shape of the opening 52A on the optical characteristics can be ignored.

As described above, according to the present embodiment, the electrode portion 40 and the first non-electrode portion 42 of the optical element 10 are formed radially about the virtual axis 38 and outward in the radial direction of the virtual axis 38. Since the width gradually increases as it reaches, the center of the second liquid 16 and the virtual axis 48 coincide with each other even though the same voltage is applied to each electrode portion 40. Since the shape of the interface 48 between the first liquid 14 and the second liquid 16 is stabilized at the position where the light is transmitted, the eccentricity of the light transmission path 52 (opening 52A) is prevented.
Accordingly, it goes without saying that it is advantageous in preventing the deterioration of the optical characteristics due to the aberration caused by the decentration of the light transmission path 52 of the optical element 10 and the occurrence of shading due to the nonuniformity of the peripheral light amount. As described above, since a control circuit for applying different voltages to the plurality of electrode portions according to the eccentricity of the light transmission path is not required, the optical element 10 can be simplified and reduced in cost. In addition, the voltage application means 22 is only required to apply the same voltage to each electrode section 40, which is advantageous in reducing power consumption during operation of the voltage application means 22.

(Second Embodiment)
Next, a second embodiment will be described.
The second embodiment is different from the first embodiment in that a wiring portion is provided on the inner surface of the second end face wall 26 and the electrode portion 40 is connected to the voltage applying means 22 via the wiring portion. Yes.
FIG. 10 is an explanatory diagram showing the configuration of the optical element 10 according to the second embodiment. In the following embodiment, the same or similar parts as those in the first embodiment are denoted by the same reference numerals. To do.
As shown in FIG. 10, also in the second embodiment, the second electrode 20 has a thickness of the container 12 in a plane orthogonal to the thickness direction of the container 12 as in the first embodiment. It consists of a plurality of electrode portions 40 extending in the radial direction around a single virtual axis 38 extending in the direction.
In the second embodiment, a frame-shaped first wiring portion 54 is formed on the inner surface of the second end face wall 26 along the outer periphery of the second end face wall 26.
The plurality of electrode portions 40, the first non-electrode portion 42, and the second non-electrode portion 44 are provided at the center of the second end face wall 26, as in the first embodiment.
A second wiring portion 56 that connects the electrode portion 40 and the first wiring portion 54 is provided on the radially outer side of each first non-electrode portion 42, and each electrode portion 40 is interposed via the second wiring portion 56. Are electrically connected to the first wiring portion 54.
The first wiring portion 54 is connected to the electrode of the voltage applying means 22 by a wiring member (not shown), and the same voltage is applied to each electrode portion 40 from the voltage applying means 22 via the first and second wiring portions 54 and 56. Is applied.
Further, the first and second wiring portions 54 and 56 are formed of a conductive material having transparency similarly to the electrode portion 40.
In the second embodiment, the third non-electrode portion 46 is separated from the first and second non-electrode portions 42 and 44 by the first and second wiring portions 54 and 56. This is different from the first embodiment.
According to the second embodiment, it is a matter of course that the same effect as in the first embodiment can be obtained, and the same voltage is applied to each electrode unit 40 via the first and second wiring units 54 and 56. Can be applied, which is advantageous in simplifying the wiring member and reducing the cost.

(Third embodiment)
Next, a third embodiment will be described.
The third embodiment is different from the first embodiment in the shape of the electrode section 40.
FIG. 11 is an explanatory diagram showing the configuration of the optical element 10 according to the third embodiment.
As shown in FIG. 11, similarly to the first embodiment, the second electrode 20 is a single virtual extending in the thickness direction of the container 12 in a plane orthogonal to the thickness direction of the container 12. It is composed of a plurality of electrode portions 40 extending in the radial direction around the axis 38, and in the present embodiment, it is composed of four electrode portions 40.
A first non-electrode part 42 in which no electrode part 40 is formed is formed between the electrode parts 40 adjacent in the circumferential direction of the virtual axis 38.
Each electrode portion 40 and each first non-electrode portion 42 have a width along the circumferential direction of the imaginary axis 38, and each electrode portion 40 gradually increases in width as the electrode portion 40 goes radially outward. It is formed to be large.
Each first non-electrode portion 42 is formed such that the width of the first non-electrode portion 42 gradually increases as it goes outward in the radial direction.
In the third embodiment, the electrode portions 40 are formed in the same shape and size, and the first non-electrode portions 42 are formed in the same shape and size between the electrode portions 40.

  In the third embodiment, unlike the first embodiment, the second and third non-electrode portions 44 and 46 are not formed. Therefore, as shown in FIG. The interface 48 between the first liquid 14 and the second liquid 16 is positioned at a position (a) on the boundary line between each electrode portion 40 and the third non-electrode portion 46, or Although it is not possible to achieve the effect of restricting the position of the interface 48 in the radial direction by being positioned at the position (b) on the boundary line of the second non-electrode portion 44, the other effects are the same as those of the first embodiment. Is played.

(Fourth embodiment)
Next, a fourth embodiment will be described.
The fourth embodiment is also different from the first embodiment in the shape of the electrode section 40.
FIG. 12 is an explanatory diagram showing the configuration of the optical element 10 according to the fourth embodiment.
As shown in FIG. 12, similarly to the first embodiment, the second electrode 20 is a single virtual extending in the thickness direction of the container 12 in a plane orthogonal to the thickness direction of the container 12. It is composed of a plurality of electrode portions 40 extending in the radial direction around the axis 38, and in the present embodiment, it is composed of four electrode portions 40.
A first non-electrode part 42 in which no electrode part 40 is formed is formed between the electrode parts 40 adjacent in the circumferential direction of the virtual axis 38.
Each electrode portion 40 and each first non-electrode portion 42 have a width along the circumferential direction of the imaginary axis 38, and each electrode portion 40 gradually increases in width as the electrode portion 40 goes radially outward. It is formed to be large.
Each first non-electrode portion 42 is formed such that the width of the first non-electrode portion 42 gradually increases as it goes outward in the radial direction.
In the fourth embodiment, each electrode portion 40 has the same shape and the same size, extends in a fan shape radially outward from the virtual axis 38, and the radially outer edge of each electrode portion 40 has a virtual axis. It extends on a single virtual circle centered on 38.
The first non-electrode portions 42 are formed in the same shape and size between the electrode portions 40.
In addition, at the radially outer portion of the outer edge portion of each electrode portion 40, the electrode portion 40 is not formed, and a third non-electrode portion 46 connected to each first non-electrode portion 42 is provided.
In the fourth embodiment, unlike the first embodiment, since the second non-electrode portion 44 is not formed, the first liquid located on the insulating film 32 is formed as shown in FIG. The interface 48 between the electrode 14 and the second liquid 16 is located at a position (b) on the boundary line between each electrode portion 40 and the second non-electrode portion 44, and the radial position of the interface 48 is not restricted. Except for this, the same effect as the effect of the first embodiment is achieved.

(Fifth embodiment)
Next, a fifth embodiment will be described.
The fifth embodiment is also different from the first embodiment in the shape of the electrode portion 40.
FIG. 13 is an explanatory diagram showing the configuration of the optical element 10 according to the fifth embodiment.
As shown in FIG. 13, similarly to the first embodiment, the second electrode 20 has a single virtual extension extending in the thickness direction of the container 12 in a plane orthogonal to the thickness direction of the container 12. It is composed of a plurality of electrode portions 40 extending in the radial direction around the axis 38, and in the present embodiment, it is composed of four electrode portions 40.
A first non-electrode part 42 in which no electrode part 40 is formed is formed between the electrode parts 40 adjacent in the circumferential direction of the virtual axis 38.
Each electrode portion 40 and each first non-electrode portion 42 have a width along the circumferential direction of the imaginary axis 38, and each electrode portion 40 gradually increases in width as the electrode portion 40 goes radially outward. It is formed to be large.
Each first non-electrode portion 42 is formed such that the width of the first non-electrode portion 42 gradually increases as it goes outward in the radial direction.
In the fifth embodiment, each electrode portion 40 has the same shape and size, and the outer edge portion in the radial direction of each electrode portion 40 has a frame shape formed along the outer periphery of the inner surface of the second end face wall 26. The wiring part 58 is electrically connected, and the wiring part 58 is formed of a transparent conductive material like the electrode part 40.
The wiring part 58 is connected to the electrode of the voltage application means 22 by a wiring member (not shown), and is configured so that the same voltage is applied to each electrode part 40 from the voltage application means 22 via the wiring part 58.
The first non-electrode portions 42 are formed in the same shape and size between the electrode portions 40.
In addition, a second non-electrode portion 44 in which the electrode portion 40 is not formed is provided in a circular range around the virtual axis 38 on the plane, and each electrode portion 40 has a radius of the second non-electrode portion 44. Each first non-electrode part 42 extends radially outward from the outer edge of the second non-electrode part 44.

In the fifth embodiment, unlike the first embodiment, the third non-electrode portion 46 is not formed. Therefore, as shown in FIG. 7, the first liquid located on the insulating film 32 is used. The interface 48 between the electrode 14 and the second liquid 16 is positioned at a position (A) on the boundary line between each electrode portion 40 and the third non-electrode portion 46, and the radial position of the interface 48 is not restricted. Except for this, the same effect as the effect of the first embodiment is achieved.
Further, in the fifth embodiment, as in the second embodiment, the same voltage is applied to each electrode portion 40 through the wiring portion 58, thereby simplifying the wiring member and reducing the cost. This is advantageous.
In the fifth embodiment, the case where the second electrode 20 is configured by the four electrode portions 40 has been described. However, the number of the electrode portions 40 is arbitrary, for example, as shown in FIG. The second electrode 20 may be constituted by eight electrode portions 40, or the second electrode 20 may be constituted by twelve electrode portions 40 as shown in FIG.
Thus, as the number of electrode portions 40 is increased, the electric field force applied to the first liquid 14 can be increased, which is advantageous in preventing eccentricity of the light transmission path 52 (opening 52A).

(Sixth embodiment)
Next, a sixth embodiment will be described.
In the sixth embodiment, in addition to the plurality of electrode portions 40 and the plurality of first non-electrode portions 42, a central non-electrode portion 60 separated from the first non-electrode portion 42 is provided at the center thereof. The point is different from the first embodiment.
FIG. 16 is an explanatory diagram showing the configuration of the optical element 10 according to the sixth embodiment.
As shown in FIG. 16, a circular central non-electrode part 60 centering on a single virtual axis 38 extending in the thickness direction of the container 12 in a plane orthogonal to the thickness direction of the container 12 is provided. Yes.
Within the plane, on the radially outer side of the central non-electrode part 60, a plurality of electrode parts 40 are provided extending radially in the center of the virtual axis 38 as in the first embodiment. A first non-electrode portion 42 is provided between the portions 40.
In the present embodiment, the second electrode 20 is composed of four electrode portions 40.
Each electrode portion 40 and each first non-electrode portion 42 have a width along the circumferential direction of the imaginary axis 38, and each electrode portion 40 gradually increases in width as the electrode portion 40 goes radially outward. It is formed to be large.
Each first non-electrode portion 42 is formed such that the width of the first non-electrode portion 42 gradually increases as it goes outward in the radial direction.
In the present embodiment, each electrode portion 40 has the same shape and size, and each first non-electrode portion 42 has the same shape and size.
Further, the inner edge portion in the radial direction of each electrode portion 40 is electrically connected by an annular wiring portion 62 extending along the outer periphery of the central non-electrode portion 60, and the annular wiring portion 62 is transparent like the electrode portion 40. It is made of a conductive material having a property.
The central non-electrode portion 60 and each first non-electrode portion 42 are separated by an annular wiring portion 62.
Further, the outer edge portion in the radial direction of each electrode portion 40 is electrically connected by a frame-like wiring portion 58 formed along the outer periphery of the inner surface of the second end face wall 26, and the wiring portion 58 is connected to the electrode portion 40. Similarly to the above, it is made of a conductive material having transparency.
The radially outer edge of each first non-electrode portion 42 on the radially outer side is formed in a straight line extending in a tangential direction on a single virtual circle with the virtual axis 38 as the center.

In the sixth embodiment, since the central non-electrode part 60 is provided, the interface 48 between the first liquid 14 and the second liquid 16 located on the insulating film 32 is located on the central non-electrode part 60. In the state where the opening 52A is at the maximum opening diameter Dmax, an effect of preventing eccentricity of the light transmission path 52 (opening 52A) is exhibited.
Further, in a region where a large electric field can be applied over the entire circumference in the circumferential direction of the first liquid 14 surrounding the second liquid 16 of each electrode part 40, it is advantageous for improving the response of the diaphragm.
Further, the interface 48 between the first liquid 14 and the second liquid 16 located on the insulating film 32 is located on the plurality of electrode portions 40 (the opening 52A has a minimum opening diameter Dmin from an intermediate opening diameter). In a state in the middle range), the effect of preventing the eccentricity of the light transmission path 52 (opening 52A) is exhibited as in the first embodiment.
In the sixth embodiment, in FIG. 16, the interface 48 between the first liquid 14 and the second liquid 16 located on the insulating film 32 is connected to each first non-electrode portion 42 and a frame-like wiring. Even if it is positioned on the boundary line of the portion 58, the effect of restricting the radial position of the interface 48 is not achieved. That is, in the sixth embodiment, as shown in FIG. 7, the interface 48 between the first liquid 14 and the second liquid 16 located on the insulating film 32 is connected to each electrode portion 40 and the third non-electrode. The action of restricting the position of the interface 48 in the radial direction is not exhibited as in the case where the part 46 is positioned on the boundary line (A).
However, if the outer edge portion in the radial direction of each electrode portion 40 on the outer side in the radial direction is formed so as to extend on a single virtual circle with the virtual axis 38 as the center, as in the first embodiment. Of course, the effect of regulating the radial position of the interface 48 is achieved.

(Seventh embodiment)
Next, a seventh embodiment will be described.
The seventh embodiment differs from the first embodiment in that the optical element 10 constitutes a lens.
The configuration of the optical element 10 of the seventh embodiment is substantially the same as that of the first embodiment except that the compositions of the first and second liquids 14 and 16 are different. Differences from the first embodiment will be described.
FIG. 17 is a longitudinal sectional view showing the configuration of the optical element 10 in the seventh embodiment, and FIG. 18 is a view taken along the line AA in FIG.
The optical element 10 deforms the shape of the interface 48 between the first liquid 14 and the second liquid 16 into a curved surface by applying a voltage from the voltage applying unit 22, so that the first and second end face walls 24 and 26 are formed. The light travels in the thickness direction of the container 12, which faces each other, and refracts light passing through the interface 48.
As illustrated in FIGS. 17 and 18, the optical element 10 includes the container 12, the first liquid 14, the second liquid 16, and the first electrode 18, as in the first embodiment. The second electrode 20 and the voltage applying means 22 are included.
The first liquid 14 has polarity or conductivity and is enclosed in the storage chamber 30.
The second liquid 16 is not mixed with the first liquid 14 and is enclosed in the storage chamber 30.
The first liquid 14 and the second liquid 16 are transparent and have substantially the same specific gravity, and the refractive index of the second liquid 16 is formed higher than the refractive index of the first liquid 14. .
The shape and arrangement of the first electrode 18 and the second electrode 20 are the same as in the first embodiment, and the electrode portion 40 and the first non-electrode portion 42 of the optical element 10 are radially centered about the virtual axis 38. The width of the imaginary shaft 38 is gradually increased toward the outside in the radial direction.

Next, the operation of the optical element 10 will be described.
FIGS. 19A, 19B, and 19C are cross-sectional views illustrating the operation when voltages V1, V2, and V3 are applied to the first and second electrodes 18 and 20 of the optical element 10, respectively.
As shown in FIG. 17, when the voltage V is not applied from the voltage application means 22 to the first electrode 18 and the second electrode 20, the shape of the interface 60 between the first and second liquids 14 and 16 is the first. , Which is determined by the balance between the surface tension of the second liquids 14 and 16 and the interfacial tension on the water repellent film 36, and forms a gently convex curved surface from the second liquid 16 toward the first liquid 14. Yes.
Here, since the refractive index of the second liquid 16 is higher than the refractive index of the first liquid 14, it passes through the first and second end face walls 24, 26 in the thickness direction of the container 12. The light traveling and passing through the interface 48 is refracted at the interface 48, and therefore the optical element 10 constitutes a lens having a power for converging the light.

Next, as shown in FIG. 19A, when the voltage V1 (> 0) is applied from the voltage application means 22 to the first electrode 18 and the second electrode 20, the interface 48 is affected by electrocapillarity. The inclination of the curved curved surface (spherical surface) becomes large.
Next, as shown in FIG. 19B, when a voltage V2 (> V1) is applied from the voltage application means 22 to the first electrode 18 and the second electrode 20, a convex curved surface ( The slope of the (spherical) curve is further increased.
Next, as shown in FIG. 19C, when a voltage V3 (> V2) is applied from the voltage application means 22 to the first electrode 18 and the second electrode 20, a convex curved surface ( The slope of the (spherical) curve is further increased.
Therefore, by adjusting the voltage applied from the voltage application means 22 to the first electrode 18 and the second electrode 20, the focal length of the lens can be varied by changing the curvature of the interface 48 (the lens power can be varied). ).
As in the first embodiment, the optical element 10 constituting the lens can be applied to an imaging optical system of an imaging apparatus such as a digital still camera or a video camera.

In the optical element 10, when the voltage applied between the first electrode 18 and the second electrode 20 is increased or decreased from V1 to V3, the shape of the interface 48 changes and the focal length of the lens changes. Regardless of the change in voltage applied between the first electrode 18 and the second electrode 20, the lens always keeps its center coincident with the virtual axis 38, and the center of the lens is the virtual axis. Even if the lens is deviated from the position 38 and decentered, the center of the lens is automatically restored so as to coincide with the virtual axis 38.
That is, as in the first embodiment, the electrode part 40 and the first non-electrode part 42 of the optical element 10 are formed radially around the virtual axis 38 and reach the outside in the radial direction of the virtual axis 38. As the width gradually increases, the center of the second liquid 16 and the virtual axis 48 coincide with each other even though the same voltage is applied to each electrode portion 40. Thus, since the shape of the interface 48 between the first liquid 14 and the second liquid 16 is stabilized, the lens is prevented from being decentered.
Further, as shown in FIG. 7, the interface 48 between the first liquid 14 and the second liquid 16 located on the insulating film 32 is positioned on the boundary line between each electrode part 40 and the third non-electrode part 46 ( The position of the interface 48 in the radial direction is regulated by positioning the interface 48 at the position (b) on the boundary line between each electrode portion 40 and the second non-electrode portion 44. The position restriction can be performed in the same manner as in the first embodiment.
Accordingly, in the seventh embodiment as well, as in the first embodiment, it is of course advantageous to prevent the optical characteristics of the optical element 10 from being deteriorated, and is eccentric as in the conventional optical element. Accordingly, a control circuit for applying different voltages to the plurality of electrode portions is not required, which is advantageous for simplifying and reducing the cost of the optical element 10, and the voltage applying means 22. Since it is only necessary to apply the same voltage to each electrode portion 40, it is advantageous in reducing the power consumption during operation of the voltage applying means 22.

  In the seventh embodiment, the case where the second electrode 20 of the optical element 10 is configured similarly to the first embodiment has been described. However, the configuration of the second electrode 20 is the second configuration. Of course, it may be configured similarly to the sixth embodiment.

1 is a longitudinal sectional view showing a configuration of an optical element 10. It is an AA arrow directional view of FIG. (A), (B), (C) is sectional drawing explaining operation | movement when voltage V1, V2, V3 is applied to the 1st, 2nd electrodes 18 and 20 of the optical element 10. FIG. (A), (B), (C) is a top view of FIG. 3 (A), (B), (C). FIG. 6 is an explanatory view showing a state where the center of a light transmission path 52 is coincident with a virtual axis 38; FIG. 6 is an explanatory view showing a state where the center of the light transmission path 52 is deviated from the virtual axis 38 and decentered. It is explanatory drawing which shows the position of the interface. It is a block diagram which shows the example which applied the optical element 10 to the imaging optical system of an imaging device. It is a principle explanatory view of electrocapillary phenomenon, (A) is a figure showing the state before voltage application, and (B) is a figure showing the state after voltage application. It is explanatory drawing which shows the structure of the optical element 10 of 2nd Embodiment. It is explanatory drawing which shows the structure of the optical element 10 of 3rd Embodiment. It is explanatory drawing which shows the structure of the optical element 10 of 4th Embodiment. It is explanatory drawing which shows the structure of the optical element 10 of 5th Embodiment. It is explanatory drawing which shows the modification of 5th Embodiment. It is explanatory drawing which shows the modification of 5th Embodiment. It is explanatory drawing which shows the structure of the optical element 10 of 6th Embodiment. It is a longitudinal cross-sectional view which shows the structure of the optical element 10 in 7th Embodiment. It is an AA arrow directional view of FIG. (A), (B), (C) is sectional drawing explaining operation | movement when voltage V1, V2, V3 is applied to the 1st, 2nd electrodes 18 and 20 of the optical element 10. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Optical element, 12 ... Container, 14 ... 1st liquid, 16 ... 2nd liquid, 18 ... 1st electrode, 20 ... 2nd electrode, 22 ... Voltage application means, 24 …… First end face wall, 26 …… Second end face wall, 28 …… Side wall, 30 …… Housing chamber, 40 …… Electrode portion, 42 …… First non-electrode portion, 48 …… Interface .

Claims (13)

A container having first and second end face walls facing each other and a side wall connecting the first and second end face walls, and a sealed storage chamber formed therein;
A polar or conductive first liquid sealed in the storage chamber;
A second liquid enclosed in the storage chamber and not mixed with the first liquid;
A first electrode and a second electrode for applying an electric field to the first liquid;
Voltage applying means for applying a voltage between the first electrode and the second electrode,
The transmittance of the first liquid is formed lower than the transmittance of the second liquid,
By applying voltage by the voltage applying means, the interface between the first liquid and the second liquid is deformed, passes through the first and second end face walls and the second liquid portion, and the first and second liquids. An optical element in which a light transmission path extending in the thickness direction of the container, which is a direction in which end walls face each other, is formed,
The first electrode is formed on an inner surface of the first end face wall facing the storage chamber,
The second electrode is formed on the inner surface of the second end wall facing the storage chamber,
The second electrode is composed of a plurality of electrode portions extending in the radial direction around a single virtual axis extending in the thickness direction of the container,
A first non-electrode part in which the electrode part is not formed is formed between the electrode parts adjacent in the circumferential direction of the virtual axis,
The electrode portions and the first non-electrode portions each have a width along the circumferential direction of the virtual axis,
Each of the electrode portions is formed such that the width of the electrode portion gradually increases as it goes outward in the radial direction,
Each of the first non-electrode portions is formed such that the width of the first non-electrode portion gradually increases as it goes outward in the radial direction.
An optical element.   A second non-electrode part in which the electrode part is not formed is provided in a circular range centering on the virtual axis, and each electrode part is provided outside the second non-electrode part in the radial direction. The optical element according to claim 1.   2. The optical element according to claim 1, wherein each of the electrode portions is formed in the same shape and size, and each of the first non-electrode portions is formed in the same shape and size. Each of the electrode portions has the same shape and the same size, and extends in a fan shape radially outward from the virtual axis.
The radially outer edge portion of each electrode portion extends on a single virtual circle centered on the virtual axis,
The first non-electrode parts are formed in the same shape and size between the electrode parts,
The optical element according to claim 1. Each of the electrode portions has the same shape and the same size, and extends in a fan shape radially outward from the virtual axis.
The radially outer edge portion of each electrode portion extends on a single virtual circle centered on the virtual axis,
The first non-electrode parts are formed in the same shape and size between the electrode parts,
The radially outer portion of the outer edge of each electrode part is provided with a third non-electrode part where the electrode part is not formed.
The optical element according to claim 1. A second non-electrode part in which the electrode part is not formed is provided in a circular range around the virtual axis;
Each of the electrode portions is provided on the outer side in the radial direction of the second non-electrode portion,
A first wiring portion is provided along an outer periphery of a portion where the second end face wall faces the accommodation chamber;
Each of the electrode portions has the same shape and the same size, and extends in a fan shape on the outer side in the radial direction of the second non-electrode portion with the imaginary axis as the center. Extending on a single virtual circle around the virtual axis,
Each of the first non-electrode parts has the same shape and the same size, and extends in a fan shape radially outward from the second non-electrode part between the electrode parts,
The radially outer portion of the outer edge portion of each electrode portion is provided with a third non-electrode portion that is not formed with the electrode portion and is separated from each first non-electrode portion,
A second wiring portion that connects the electrode portion and the first wiring portion is provided between the third non-electrode portions;
The optical element according to claim 1. A second non-electrode part in which the electrode part is not formed is provided in a circular range around the virtual axis;
Each of the electrode portions is provided on the outer side in the radial direction of the second non-electrode portion,
A wiring portion is provided along an outer periphery of a portion where the second end face wall faces the storage chamber,
Each of the electrode portions has the same shape and the same size, and extends in a fan shape around the imaginary axis on the radially outer side of the second non-electrode portion,
The outer edge portion in the radial direction of each electrode portion is connected to the wiring portion,
The optical element according to claim 1. The first liquid and the second liquid are formed to have substantially the same specific gravity,
The optical element according to claim 1.   The optical element according to claim 1, wherein an insulating film is formed over the entire area of the second electrode formed on the inner surface of the second end face wall. A first film having higher wettability with respect to the first liquid than the wettability with respect to the second liquid is formed over the entire inner surface of the first end face wall;
The wettability with respect to the second liquid is higher than the wettability with respect to the first liquid over the entire inner surface of the second end face wall including the second electrode formed on the inner surface of the second end face wall. A second film is formed;
The optical element according to claim 1. A container having first and second end face walls facing each other and a side wall connecting the first and second end face walls, and a sealed storage chamber formed therein;
A transparent first liquid having polarity or conductivity enclosed in the storage chamber;
A transparent second liquid enclosed in the storage chamber and not mixed with the first liquid;
A first electrode and a second electrode for applying an electric field to the first liquid;
Voltage applying means for applying a voltage between the first electrode and the second electrode,
By deforming the interface shape of the first liquid and the second liquid into a curved surface by applying a voltage by the voltage applying means, the first and second end face walls are in a direction facing each other. An optical element that refracts light traveling in the thickness direction and passing through the interface,
The first electrode is formed on an inner surface of the first end face wall facing the storage chamber,
The second electrode is formed on the inner surface of the second end wall facing the storage chamber,
The second electrode is composed of a plurality of electrode portions extending in the radial direction around a single virtual axis extending in the thickness direction of the container,
A first non-electrode part in which the electrode part is not formed is formed between the electrode parts adjacent in the circumferential direction of the virtual axis,
The electrode portions and the first non-electrode portions each have a width along the circumferential direction of the virtual axis,
Each of the electrode portions is formed such that the width of the electrode portion gradually increases as it goes outward in the radial direction,
Each of the first non-electrode portions is formed such that the width of the first non-electrode portion gradually increases as it goes outward in the radial direction.
An optical element.   The optical element according to claim 11, wherein the first liquid and the second liquid have substantially the same specific gravity. 12. The optical element according to claim 11, wherein the refractive index of the second liquid is higher than the refractive index of the first liquid.

Images