JP2009288798A - Optical element and imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element which is advantageous for improving the response property and an imaging device provided with the optical element. <P>SOLUTION: A first liquid 14 does not move and is held positioned at the original point when electric voltage E is applied on a central electrode member 40 and two other electrode members 38 and 42 are opened as shown in the Fig.7(B). The first liquid 14 is surrounded by a second liquid 16, a half of the first liquid 14 is moved towards one of retracting rooms 34 and the other half of the first liquid 14 moves towards the other retracting room 34 when an electric voltage application means 22 opens the central electrode member 40 and applies the electric voltage E on the two other electrode members 38 and 42 as shown in the Fig.7(A). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an optical element and an imaging apparatus.

Proposing an optical element that changes the optical properties of a liquid by changing the shape of the conductivity or liquid using an electrocapillary phenomenon (electrowetting phenomenon) by applying an electric field to a polar or conductive liquid. Has been.
Further, there has been proposed a liquid moving means for moving the liquid itself in a desired direction by applying an electric field to the polar or conductive liquid (see Patent Document 1).
In this liquid moving means, a first electrode that is in contact with a liquid (droplet), a plurality of second electrodes that are provided to the liquid via an insulating layer and are arranged along a predetermined direction, and a first electrode, Control means for individually controlling the voltage applied between each second electrode, and changing the position of the voltage application to the second electrode by the control means in the predetermined direction, the liquid on the insulating layer is changed to the predetermined It moves in the direction.

JP 2004-336898 A

By the way, when such a liquid moving means is arranged on the optical axis of the imaging optical system of the imaging apparatus and the shutter is configured by moving the liquid in a direction orthogonal to the optical axis, the response of the shutter can be improved. In order to achieve this, it is required to increase the moving speed of the liquid.
However, the above prior art has a limit in increasing the electric field strength acting on the liquid, and there is a limit in increasing the moving speed of the liquid.
The present invention has been made in view of such circumstances, and an object thereof is to provide an optical element that is advantageous in improving responsiveness and an imaging apparatus including such an optical element.

In order to achieve the above object, the present invention provides a container having a storage chamber, a polar or conductive first liquid sealed in the storage chamber, and the first liquid sealed in the storage chamber. A second liquid that does not mix with each other, a first electrode and a second electrode for applying an electric field to the first liquid, and a voltage that applies a voltage between the first electrode and the second electrode And an optical device that moves the first liquid in the second liquid in the storage chamber by changing a position of voltage application to the first and second electrodes by the voltage applying means. The storage chamber is an element, the adjustment chamber for adjusting the amount of transmitted light depending on the presence or absence of the first liquid, and the first liquid communicated with the adjustment chamber and retracted from the adjustment chamber A plurality of evacuation chambers capable of accommodating a plurality of evacuation chambers. The retracting chamber includes first and second end face walls facing each other in the light transmitting direction, and the first electrode includes the first and second end walls of the adjusting chamber and the plurality of retracting chambers. The second electrode is provided on one end face wall of the end face walls, and the second electrode is provided on the other end face wall of the first and second end face walls.
In addition, the present invention provides a container having a storage chamber, 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, An optical element that moves the first liquid in the second liquid in the storage chamber by changing a position of voltage application to the first and second electrodes by the voltage applying means, The storage chamber is configured to include first and second end face walls facing each other in a direction in which light is transmitted, and the first electrode is one end face wall of the first and second end face walls. The second electrode is provided on the other end face of the first and second end face walls. The second electrode includes a central electrode member and a plurality of peripheral electrode members provided around the central electrode member. The first electrode includes the central electrode member and the plurality of peripheral electrode members. It is comprised by the single electrode member which opposes the surrounding electrode member of this.
In addition, the present invention includes a photographing optical system that guides a subject image, an imaging element provided on the optical axis of the photographing optical system, and an optical element provided in front of the imaging element on the optical axis. The optical element includes a container having a storage chamber, 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 first liquid is moved in the second liquid in the storage chamber by changing a position of voltage application to the first and second electrodes by the voltage applying means, and the storage The chamber is an adjustment for adjusting the amount of transmitted light depending on the presence or absence of the first liquid. And a plurality of evacuation chambers communicating with the adjustment chamber and capable of accommodating the first liquid evacuated from the adjustment chamber. The adjustment chamber and the plurality of evacuation chambers transmit the light. First and second end face walls opposed to each other in the direction to be operated, wherein the first electrode is one end face wall of the first and second end face walls of the adjustment chamber and the plurality of evacuation chambers. The second electrode is provided on the other end face wall of the first and second end face walls.
In addition, the present invention includes a photographing optical system that guides a subject image, an imaging element provided on the optical axis of the photographing optical system, and an optical element provided in front of the imaging element on the optical axis. The optical element includes a container having a storage chamber, 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. 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 first liquid is moved in the second liquid in the storage chamber by changing a position of voltage application to the first and second electrodes by the voltage applying means, and the storage The chamber includes first and second end face walls facing each other in the direction in which light is transmitted. The first electrode is provided on one end surface wall of the first and second end surface walls, and the second electrode is formed of the first and second end surface walls. The second electrode is provided on the other end wall, and the second electrode includes a central electrode member and a plurality of peripheral electrode members provided around the central electrode member, and the first electrode is the central electrode. It is comprised by the single electrode member which opposes a member and the said several surrounding electrode member, It is characterized by the above-mentioned.

  According to the present invention, since the first liquid is divided and moved by applying a voltage to the first liquid by the plurality of electrode members provided in the storage chamber, the first liquid can be kept as a unit. Compared with the case of moving, the mass and moving distance of the first liquid can be reduced, so that the moving speed of the first liquid can be increased, which is advantageous in improving the response of the optical element. Become.

(A) is sectional drawing explaining the principle of a liquid movement, (B) is an AA arrow directional view of (A). (A) is a longitudinal cross-sectional view which shows the structure of the optical element 10, (B) is AA sectional view taken on the line of (A). (A) is a BB line arrow view of FIG. 2 (A), (B) is CC line arrow view of FIG. 2 (A). FIG. 5 is an operation explanatory diagram of the optical element 10. FIG. 5 is an operation explanatory diagram of the optical element 10. FIG. 5 is an operation explanatory diagram of the optical element 10. (A), (B) is operation | movement explanatory drawing of the optical element 10. FIG. 1 is a block diagram illustrating a configuration of an imaging apparatus 100. FIG. 2 is a diagram illustrating a configuration of a photographing optical system 104 of the imaging apparatus 100. FIG. (A) is a figure explaining the movement of the 1st liquid 14 in a comparative example, (B) is a figure explaining the movement of the 1st liquid 14 in this Embodiment. (A), (B) is a top view which shows the modification of the 2nd electrode 20. FIG. It is a longitudinal cross-sectional view which shows the structure of the optical element 10 of 2nd Embodiment. (A), (B) is operation | movement explanatory drawing of the optical element 10 of 2nd Embodiment. It is operation | movement explanatory drawing of the optical element 10 of 3rd Embodiment. It is operation | movement explanatory drawing of the optical element 10 of 3rd Embodiment. (A), (B), (C) is operation | movement explanatory drawing of the optical element 10 of 4th Embodiment. (A), (B) is operation | movement explanatory drawing of the optical element 10 of 5th Embodiment. 2 is a plan view of a first electrode 18. FIG. It is operation | movement explanatory drawing of the optical element 10 of 6th Embodiment. It is operation | movement explanatory drawing of the optical element 10 of 6th Embodiment. It is operation | movement explanatory drawing of the optical element 10 of 6th Embodiment.

(First embodiment)
First, the operation principle of liquid movement by an electric field will be described.
1A is a cross-sectional view illustrating the principle of liquid movement, and FIG. 1B is a view taken along the line AA in FIG.
As shown in FIGS. 1A and 1B, the first and second end face walls 1A and 1B and the first and second end face walls 1A facing each other with a gap g in the light transmitting direction. A housing chamber 1 is formed by a side wall 1C connecting 1B.
A first electrode 2 is formed on the entire inner surface of the first end wall 1A, and the surface of the first electrode 2 facing the storage chamber 1 is covered with a water repellent film 3A.
The second electrode 4 is provided on the inner surface of the second end face wall 1B, and the second electrode 4 is a direction in which the two electrode bodies 4A and 4B are opposed to the first and second end face walls 1A and 1B. Are arranged side by side along a virtual axis L extending in a direction perpendicular to the axis.
The entire surface of the two electrode bodies 4A and 4B and the entire inner surface of the second end face wall 1B are covered with the insulating film 5, and the entire surface of the insulating film 5 facing the storage chamber 1 is covered with the water repellent film 3B.
The storage chamber 1 is filled with a first liquid 6 and a second liquid 7, the first liquid 6 has polarity or conductivity, and the second liquid 7 is around the first liquid 6. And is not mixed with the first liquid.
The first electrode 2 faces the first liquid 6 through the water repellent film 3A, and the second electrode 4 faces through the insulating film 5 and the water repellent film 3B.

First, in the initial state, the two electrode bodies 4A and 4B of the first electrode 2 and the second electrode 4 are both connected to the ground level, and in this state, the first liquid 6 is in one electrode body 4A. It is located over the entire region and the portion of the other electrode body 4B adjacent to the electrode body 4A.
In this state, the first liquid 6 has a circular shape in plan view as indicated by a solid line in FIGS. 1A and 1B due to its surface tension.
Here, when the voltage E is applied to the other electrode body 4 </ b> B, a positive charge is charged at a location where the insulator 5 faces the first liquid 6, whereby the first liquid 6 faces the insulator 5. An electric field (electrostatic force) acts on the location, and negative charges are attracted to the location where the first liquid 6 faces the insulator 5, in other words, molecules constituting the first liquid 6 are attracted.
Then, the shape of the first liquid 6 changes so as to be drawn toward the electrode body 4B as shown by the broken lines in FIGS. 1A and 1B, and the first liquid 6 eventually becomes the second liquid 6. The entire first liquid 6 moves along the extending direction of the virtual axis L from one electrode body 4A to the other electrode body 4B while being surrounded by the liquid 7.
The water repellent films 3A and 3B are generated between the liquid 6 and the first and second end face walls 1A and 1B when the first liquid 6 moves on the first and second electrodes 2 and 4. It serves to reduce resistance and facilitate movement.
Thus, the first liquid 6 is moved by applying an electric field to the first liquid 6 having polarity or conductivity by the first and second electrodes 2 and 4.

Next, the optical element 10 of the present embodiment will be described.
In the present embodiment, the optical element 10 constitutes a shutter.
2A is a longitudinal sectional view showing the configuration of the optical element 10, and FIG. 2B is a sectional view taken along line AA in FIG.
3A is a view taken along the line BB in FIG. 2A, and FIG. 3B is a view taken along the line CC in FIG.
4, 5, and 6 are explanatory diagrams of the operation of the optical element 10.
As shown in FIGS. 2A and 2B, the optical element 10 includes a container 12, a first liquid 14,
The second liquid 16, the first electrode 18 and the second electrode 20, and a voltage applying means 22 (see FIG. 4) are included.
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. A storage chamber 30 is provided which is sealed by the first and second end face walls 24 and 26 and the side wall 28. The first and second end face walls 24 and 26 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.
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.
Here, the thickness direction of the container 12 is a direction in which the first end face wall 24 and the second end face wall 26 face each other, and matches the direction in which light passes through the optical element 10.

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 storage chamber 30 has a flat columnar shape, and the storage chamber 30 has a uniform rectangular cross section and extends in a direction perpendicular to the light transmission direction.
The storage chamber 30 includes an adjustment chamber 32 and a plurality of evacuation chambers 34. In other words, the adjustment chamber 32 and the plurality of evacuation chambers 34 are opposed to each other in the light transmitting direction. End face walls 24 and 26.
The adjustment chamber 32 is for adjusting the light transmission amount depending on the presence or absence of the first liquid 14, and the retreat chamber 34 communicates with the adjustment chamber 32 and is retreated from the adjustment chamber 32. Can be accommodated.
In the present embodiment, the adjustment chamber 32 is located at the center in the extending direction of the storage chamber 30, and the evacuation chambers 34 are provided on both sides in the extending direction of the storage chamber 30. In the present embodiment, the extending direction of the storage chamber 30 is parallel to the long side direction of the container 12.
In other words, the two evacuation chambers 34 communicate with the adjustment chamber 32 from a direction orthogonal to the light transmission direction, and extend on both sides of the adjustment chamber 32 in a direction orthogonal to the light transmission direction. It is provided on a straight line.

The first liquid 14 has polarity or conductivity and is enclosed in the storage chamber 30.
The second liquid 16 does not mix with the first liquid 14 and is enclosed in the storage chamber 30 so as to surround the first liquid 14.
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. In the case of using carbon black, it is preferable to subject the surfaces to hydrophilic coating treatment so that the carbon black is evenly 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 made of transparent silicone oil. By using a low-viscosity silicone oil that constitutes the second liquid 16, the viscosity resistance between the first and second liquids 14 and 16 is reduced, and the first liquid 14 and the first and second liquids are reduced. The friction between the end walls 24 and 26 is reduced, which is advantageous in improving the response by increasing the moving speed of the first liquid 14.
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, the first liquid 14 and the second liquid 16 may be 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.
As shown in FIGS. 2A and 3A, the first electrode 18 is provided on the first end wall 24 of the adjustment chamber 32 and the two retraction chambers 34. One electrode 18 includes a single electrode member 36 extending over the first end wall 24 of the adjustment chamber 32 and the two retreat chambers 34. In the present embodiment, as shown in FIG. 3A, the electrode member 36 is formed in a rectangular shape having a contour that is slightly smaller than the contour of the first end face wall 24.
As shown in FIG. 2A and FIG. 3B, the second electrode 20 is provided on the second end face wall 26 of the adjustment chamber 32 and the two retreat chambers 34. The two electrodes 20 are constituted by three electrode members 38, 40, 42 provided separately from each other, and one of the three electrode members 38, 40, 42 is the second electrode of the adjustment chamber 32. The remaining two electrode members 38, 42 are provided in the two retreat chambers 34 on the end face wall 26.
These three electrode members 38, 40, 42 are arranged along a straight line extending in a direction orthogonal to the direction in which the light is transmitted. In the present embodiment, the straight line is parallel to the direction of the long side of the container 12.
In the present embodiment, as shown in FIG. 3B, the three electrode members 38, 40, and 42 have the same shape and the same size, and are arranged at equal intervals.
Further, the edge portions where the electrode members 38, 40, 42 are adjacent to each other are formed as 2010 extending in a direction orthogonal to the extending direction of the straight line, and the adjacent electrode members have the uneven portions 2010 parallel to each other. It is arranged in a state of facing each other with a gap. In the present embodiment, the shape of the concavo-convex portion 2010 is a triangular wave with a uniform amplitude.
The first and second electrodes 18 and 20, that is, the electrode members 36, 38, 40, and 42 are made of a conductive material such as an ITO film (Indium Tin Oxide film) that can transmit light.
3A and 3B, reference numeral 1802 denotes a wiring portion extending from the electrode member 36, and reference numeral 2002 denotes a wiring portion extending from the electrode members 38, 40, and 42.

As shown in FIG. 4, the voltage applying means 22 is provided outside the container 12, and a ground terminal 2202 electrically connected to the first electrode 18 via a wiring portion 1802 (see FIG. 3), and a second And a plurality of voltage output terminals 2204 electrically connected to the electrode members 38, 40 and 42 of the electrode 20 via the wiring portion 2002 (see FIG. 3).
The voltage application means 22 has a power supply 22A that outputs a voltage E, and can selectively apply the voltage E to each of the electrode members 38, 40, and 42 of the second electrode 20 via the voltage output terminal 2204. It is configured.

Further, as shown in FIGS. 2A and 2B, an insulating film 44 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. Yes.
Therefore, when a voltage is applied between the first electrode 18 and the second electrode 20, for example, a positive charge is charged on the surface of the insulating film 44, thereby applying an electric field to the first liquid 14, An electric field (electrostatic force) acts on molecules constituting one liquid 14 to move the first liquid 14.

A transparent water repellent film 46 that transmits light is formed so as to cover the inner surface of the second end wall 26 and the entire area of the first electrode 18.
A water repellent film 46 is formed so as to cover the inner surface of the side wall 28.
The water repellent film 46 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 46 is configured to be smaller than the contact angle of the first liquid 14 with respect to the water repellent film 46.
The water-repellent film 46 is a resistance generated between the first liquid 14 and the first and second end face walls 24 and 26 when the first liquid 14 moves on the first and second electrodes 18 and 20. It reduces the amount of water and makes it easier to move.
The water repellent film 46 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 46, various conventionally known materials can be used.

Next, the operation of the optical element 10 will be described.
FIGS. 7A and 7B are explanatory diagrams of the operation of the optical element 10.
First, an operation when the adjustment chamber 32 of the optical element 10 changes from a state of shielding light to a state of transmitting light will be described.
In the initial state, as shown in FIG. 4, the first liquid 14 is placed at a position sandwiched between the electrode member 36 of the first electrode 18 and the center electrode member 40 of the second electrode 20 in the adjustment chamber 32. positioned.
In this state, the voltage applying means 22 applies the voltage E to the central electrode member 40, and the remaining two electrode members 38 and 42 are in an open state (or a state in which a ground potential is applied).
Therefore, the electric field due to the voltage E applied to the first electrode 18 and the central electrode member 40 acts on the first liquid 14 located at the position facing the central electrode member 40, thereby The liquid 14 is held in its position without moving, and as a result, most of the first liquid 14 faces the central electrode member 40, and two parts of the first liquid 14 are adjacent to each other. It faces the electrode members 38 and 42.
In this state, as shown in FIG. 7B, the incident light traveling toward the adjustment chamber 32 is shielded by the first liquid 14 located in the adjustment chamber 32 and having a low transmittance.

Next, as shown in FIG. 5, when the voltage applying unit 22 opens the central electrode member 40 (or a state in which a ground potential is applied) and applies the voltage E to the remaining two electrode members 38 and 42, In other words, the voltage application point to the second electrode 20 is changed to the remaining two electrode members 38 and 42.
Then, as shown in FIG. 5, the first liquid 14 is located at a position where the electric field due to the voltage E applied to the first electrode 18 and the two electrode members 38, 42 faces the central electrode member 40. By acting on the first liquid 14, half of the first liquid 14 is moved toward the one retreat chamber 34 while the first liquid 14 is surrounded by the second liquid 16. The remaining half of the liquid 14 moves toward the other evacuation chamber 34.
As a result, as shown in FIG. 6, the first liquid 14 is divided into two and stored in the two retreat chambers 34. Accordingly, half of the first liquid 14 is held in a state where it is located in one of the retreat chambers 34, and the other half of the first liquid 14 is held in a state of being located in the other retreat chamber 34.
At this time, most of the divided one first liquid 14 faces one electrode member 38, and a part of the divided one first liquid 14 faces an adjacent central electrode member 40, and is divided. Most of the other first liquid 14 thus formed faces the other electrode member 42, and a part of the other divided first liquid 14 faces the adjacent central electrode member 40.
In this state, as shown in FIG. 7A, incident light traveling toward the adjustment chamber 32 passes through the second liquid 16 located in the adjustment chamber 32 and having a high transmittance.

Next, the operation when the adjustment chamber 32 of the optical element 10 changes from a state of transmitting light to a state of shielding, contrary to the above, will be described.
As shown in FIG. 6, the voltage application means 22 applies the voltage E to the central electrode member 40 in a state where the divided first liquid 14 is accommodated in the two retreat chambers 34, and the remaining two liquids The electrode members 38 and 42 are opened (or a ground potential is applied).
Then, as shown in FIG. 5, the divided first portions are located where the electric field due to the voltage E applied to the first electrode 18 and the central electrode member 40 faces the two electrode members 38 and 42. By acting on each of the liquids 14, the divided first liquid 14 moves from the respective retracting chambers 34 toward the adjusting chambers 32 in a state where the first liquid 14 is surrounded by the second liquid 16.
As a result, as shown in FIG. 4, the first liquid 14 that has been divided into two is accommodated in the adjustment chamber 32 and united.
Accordingly, the electric field due to the voltage E applied to the first electrode 18 and the central electrode member 40 acts on the first liquid 14, so that the first liquid 14 reaches the central electrode member 40 without moving. As a result, most of the first liquid 14 faces the central electrode member 40, and a part of the first liquid 14 faces two adjacent electrode members 38 and 42. It is out.
In this state, as shown in FIG. 7B, the incident light traveling toward the adjustment chamber 32 is shielded by the first liquid 14 located in the adjustment chamber 32 and having a low transmittance.

  As described above, light can be transmitted through the adjustment chamber 32 by changing the position of voltage application by the voltage application means 22 and dividing the first liquid 14 from the adjustment chamber 32 into the two retreat chambers 34 and moving them. The optical element 10 is brought into a state where the light is blocked by moving the first liquid 14 evacuated to the two evacuation chambers 34 to the adjustment chamber 32 and combining them. Can function as a shutter.

Next, a case where the above-described optical element 10 is used as a shutter in a photographing optical system of an imaging apparatus such as a digital still camera or a video camera will be described.
FIG. 8 is a block diagram illustrating a configuration of the imaging apparatus 100, and FIG. 9 is a diagram illustrating a configuration of the photographing optical system 104 of the imaging apparatus 100.
As shown in FIG. 8, the imaging apparatus 100 has a case (not shown) that constitutes an exterior. A lens barrel 102 is incorporated in the case, and a display 112, a shutter button, and various types of shooting are provided on the surface of the case. An operation switch 116 for performing an operation is provided.
The lens barrel 102 incorporates a photographing optical system 104 and an image sensor 106 that captures a subject image captured by the photographing optical system 104.
The imaging apparatus 100 generates image data based on the imaging signal output from the imaging element 106 and records it on a storage medium 108 such as a memory card, and a display control unit that displays the image data on the display 112. 114, an image processing unit 110, a control unit 118 including a CPU that controls the display control unit 114, and the like according to operations of the shutter button and the operation switch 116.

As shown in FIG. 9, on the optical axis G, the photographic optical system 104 has a first lens group 120, a second lens group 122, a third lens group 124, from the subject toward the image sensor 106, The fourth lens group 126 and the filter group 128 are arranged in this order.
In this example, the first lens group 120 and the third lens group 124 are provided so as not to move in the optical axis direction, the second lens group 122 is provided as a zoom lens so as to be movable in the optical axis direction, The fourth lens group 126 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 120 is converted into a parallel light beam by the second lens group 122 and guided to the third lens group 124, via the fourth lens group 126 and the filter group 128. Thus, the light is converged on the image pickup surface 106A of the image pickup element 106.
The optical element 10 is disposed between the filter group 128 and the image sensor 106, and the first liquid 14 is in a state where the adjustment chamber 32 is positioned on the optical axis G and the direction in which light is transmitted is parallel to the optical axis G. Is moved so that the first liquid 14 can block the light beam guided to the image sensor 106.
Therefore, in the optical element 10, when the light beam is blocked by the movement of the first liquid 14, it is possible to control the irradiation time of the imaging surface 106 </ b> A, that is, the exposure time of the imaging element 106.
Note that the cross-sectional area of the light beam of the subject image converged by the photographic optical system 104 becomes smaller as it approaches the imaging surface 106A of the imaging element 106. Therefore, when the optical element 10 is disposed immediately before the image pickup surface 106A of the image pickup element 106 as in the present embodiment, the cross-sectional area of the light beam that is opened and shielded by the optical element 10 becomes small. The moving distance can be reduced, which is advantageous in reducing the size of the optical element 10 and improving the response.

As described above, according to the present embodiment, the first liquid 14 accommodated in the adjustment chamber 32 is divided and retracted by the electric field applied from the electrode members 38 and 42 provided in the retracting chamber 34. The first liquid 14 that has been moved to the chamber 34 and divided and accommodated in each of the retreat chambers 34 is moved from each retreat chamber 34 to the storage chamber 32 by an electric field applied from the electrode member 40 provided in the adjustment chamber 32. Moved to and merged.
Therefore, since the first liquid 14 is moved in a divided state, the mass and the moving distance of the first liquid 14 can be reduced as compared with the case where the first liquid 14 is moved as a unit. As a result, the moving speed of the first liquid 14 can be increased, which is advantageous in improving the response of the optical element 10.

Next, a comparative example will be described.
FIG. 10A is a diagram for explaining the movement of the first liquid 14 in the comparative example, and FIG. 10B is a diagram for explaining the movement of the first liquid 14 in the present embodiment.
As shown in FIG. 10B, in the optical element 10 according to the present embodiment, the first liquid 14 moves between the adjustment chamber 32 and each retreat chamber 34 in a state where the first liquid 14 is divided into two.
As shown in FIG. 10A, in the optical element 10 of the comparative example, the adjustment chamber 32 in a state where the first liquid 14 having the same volume as the first liquid 14 of the optical element 10 in the present embodiment is collected. And one of the evacuation chambers 34.
Therefore, if the volume of the first liquid 14 is the same, in this embodiment, the volume and mass of the divided first liquid 14 are each half that of the first liquid 14 of the comparative example.
In the comparative example, the amount of movement required for the first liquid 14 to move on the adjacent electrode member is substantially equal to the diameter (liquid diameter) of the first liquid 14.
On the other hand, in the embodiment, the amount of movement required for the divided first liquid 14 to move onto the adjacent electrode member and merge is approximately equal to half the amount of movement of the comparative example.
In the embodiment, since the volume of the divided first liquid 14 is half that of the comparative example, the diameter of the first liquid 14 is significantly smaller than that of the comparative example. Therefore, the divided liquid according to the present embodiment is divided. The amount of movement that the first liquid 14 should move is significantly shortened compared to the amount of movement that the first liquid 14 of the comparative example should move.
Moreover, if the applied electric field is the same, the moving speed increases as the mass of the first liquid 14 decreases.
Therefore, since the optical element 10 of the present embodiment has a smaller moving amount of the first liquid 14 and a lighter mass than the comparative example, the moving speed of the first liquid 14 is increased. It will be advantageous.

In the present embodiment, each electrode member 38, 40, 42 has an uneven portion 2010 extending in a direction perpendicular to the linear extending direction at the edge portion adjacent to each other, and the adjacent electrode members are The concavo-convex portions 2010 are arranged in a state of facing each other in parallel.
Therefore, even if the arrangement interval of the electrode members is the same dimension as the diameter of the first liquid 14 or a dimension slightly larger than the diameter, the moving direction in a state where most of the first liquid 14 is located on one electrode member. A part of the first liquid 14 can be made to face the adjacent electrode member, which is advantageous when it is desired to increase the arrangement interval of the electrode members.
The shape of the uneven portion 2010 may be a triangular wave shape with substantially constant amplitude as in this embodiment, but the shape of the uneven portion 2010 is a square wave shape with substantially constant amplitude, as shown in FIG. It goes without saying that the same effects as described above can be obtained.

Further, as shown in FIG. 11 (B), the center of the electrode member 40 provided on the end wall 26 of the adjustment chamber 32 in the extending direction of the concavo-convex portion 2010 is from other convex portions constituting the concavo-convex portion 2010. Also, a protrusion 2012 that protrudes greatly toward the end wall 26 side of the retracting chamber 34 is provided, and an unevenness is formed at the center in the extending direction of the uneven portions 2010 of the electrode members 38 and 42 provided on the end wall 26 of each retracting chamber 34. The following effects are obtained when a concave portion 2014 that is greatly depressed in the central side of the evacuation chamber 34 than the other concave portions constituting the portion 2010 is provided and the convex portion 2012 is arranged facing the concave portion 2014 with a gap. Played.
That is, when the first liquid 14 located on the electrode members 38 and 42 of each retreat chamber 34 moves toward the electrode member 40 of the adjustment chamber 32, the portion of the convex portion 2012 is another central electrode member 40. Since the first liquid 14 is in contact with a larger area than the uneven portion 2010, an electric field can be strongly applied to the first liquid 14 from the convex portion 2012.
Thereby, the center part of the 1st liquid 14 can be moved toward the electrode member 40 of the adjustment chamber 32 ahead of other parts, Therefore, the 1st liquid 14 can be moved more smoothly. This is advantageous in increasing the moving speed of the first liquid 14 from the retracting chamber 34 to the adjusting chamber 32.
In order to apply an electric field to the first liquid 14, a part of the first liquid 14 faces the adjacent electrode member while most of the first liquid 14 is positioned on one electrode member. The uneven portions 2010 are not formed at positions where the electrode members 38, 40, 42 are adjacent to each other, and may be formed linearly in a direction perpendicular to the extending direction of the straight line. Of course. However, if the uneven portion 2010 is formed, it is advantageous for increasing the moving speed as described above.

(Second Embodiment)
Next, a second embodiment will be described.
The second embodiment is that the first liquid 14 is transparent and the transmittance of the second liquid 16 is lower than the transmittance of the first liquid 14. This is different from the embodiment.
FIG. 12 is a longitudinal sectional view showing the configuration of the optical element 10 of the second embodiment, and FIGS. 13A and 13B are explanatory diagrams of the operation of the optical element 10 of the second embodiment. In the following embodiments, the same or similar parts and members as those in the first embodiment will be described with the same reference numerals.
As shown in FIG. 12, the optical element 10 includes a container 12, a first liquid 14, a second liquid 16, a first electrode 18 and a second electrode, as in the first embodiment. 20 and a voltage applying means 22.
The first liquid 14 has polarity or conductivity and is enclosed in the storage chamber 30.
The second liquid 16 does not mix with the first liquid 14 and is enclosed in the storage chamber 30 so as to surround the first liquid 14.
Further, the first liquid 14 and the second liquid 16 have substantially the same specific gravity, and the transmittance of the second liquid 16 is formed to be lower than the transmittance of the first liquid 14. .
In the present embodiment, the first liquid 14 is composed of, for example, a liquid obtained by mixing pure water, ethanol, and ethylene glycol, and the second liquid 16 is composed of a transparent silicon oil that does not transmit light. It is formed by mixing fine particles (for example, carbon black).
The container 12, the first electrode 18, the second electrode 20, and the voltage applying means 22 are configured in the same manner as in the first embodiment.

Next, the operation of the optical element 10 will be described.
First, an operation when the adjustment chamber 32 of the optical element 10 changes from a state of transmitting light to a state of shielding light will be described.
In the initial state, as shown in FIG. 12 and FIG. 13A, the first liquid 14 has an electrode member 36 of the first electrode 18 and an electrode member 40 at the center of the second electrode 20 in the adjustment chamber 32. It is located in the place between.
In this state, the voltage applying means 22 applies the voltage E to the central electrode member 40, and the remaining two electrode members 38 and 42 are in an open state (or a state in which a ground potential is applied).
Therefore, the electric field due to the voltage E applied to the first electrode 18 and the central electrode member 40 acts on the first liquid 14 located at the position facing the central electrode member 40, thereby The liquid 14 is held in its position without moving, and as a result, most of the first liquid 14 faces the central electrode member 40, and two parts of the first liquid 14 are adjacent to each other. It faces the electrode members 38 and 42.
In this state, as shown in FIG. 13A, incident light traveling toward the adjustment chamber 32 passes through the first liquid 14 located in the adjustment chamber 32 and having a high transmittance.

Next, when the voltage application means 22 opens the central electrode member 40 (or a state in which a ground potential is applied) and applies the voltage E to the remaining two electrode members 38 and 42, that is, the second electrode 20. The remaining voltage is applied to the remaining two electrode members 38 and 42.
Then, as shown in FIG. 13B, the first electric field is located at a position where the electric field due to the voltage E applied to the first electrode 18 and the two electrode members 38 and 42 faces the central electrode member 40. When the first liquid 14 is surrounded by the second liquid 16, half of the first liquid 14 moves toward the one retreat chamber 34 at the same time. The remaining half of the first liquid 14 moves toward the other retreat chamber 34.
As a result, the first liquid 14 is divided into two and stored in the two evacuation chambers 34.
Accordingly, half of the first liquid 14 is held in a state where it is located in one of the retreat chambers 34, and the other half of the first liquid 14 is held in a state of being located in the other retreat chamber 34.
At this time, most of the divided one first liquid 14 faces one electrode member 38, and a part of the divided one first liquid 14 faces an adjacent central electrode member 40, and is divided. Most of the other first liquid 14 thus formed faces the other electrode member 42, and a part of the other divided first liquid 14 faces the adjacent central electrode member 40.
In this state, as shown in FIG. 13B, incident light traveling toward the adjustment chamber 32 is shielded by the second liquid 16 located in the adjustment chamber 32 and having a low transmittance.

Next, the operation when the adjustment chamber 32 of the optical element 10 changes from a state of shielding light to a state of transmitting light will be described contrary to the above.
In a state where the divided first liquid 14 is accommodated in the two retreat chambers 34, the voltage applying means 22 applies the voltage E to the central electrode member 40 and opens the remaining two electrode members 38 and 42. State (or a state in which a ground potential is applied).
Then, as shown in FIG. 13B, the electric field generated by the voltage E applied to the first electrode 18 and the central electrode member 40 is divided at a position facing the two electrode members 38 and 42. By acting on each of the first liquids 14, the divided first liquids 14 move from the respective retracting chambers 34 toward the adjustment chambers 32 with the second liquids 16 surrounded by the surroundings.
As a result, as shown in FIG. 13A, the first liquid 14 that has been divided into two is accommodated in the adjustment chamber 32 and united.
Accordingly, the electric field due to the voltage E applied to the first electrode 18 and the central electrode member 40 acts on the first liquid 14, so that the first liquid 14 reaches the central electrode member 40 without moving. As a result, most of the first liquid 14 faces the central electrode member 40, and a part of the first liquid 14 faces two adjacent electrode members 38 and 42. It is out.
In this state, as shown in FIG. 13A, incident light traveling toward the adjustment chamber 32 is transmitted by the first liquid 14 located in the adjustment chamber 32 and having a low transmittance.
Similarly to the first embodiment, the optical element 10 according to the second embodiment also changes the location of voltage application by the voltage application means 22 to divide the first liquid 14 and adjust the adjustment chamber 32 and the two retreats. By moving between the chambers 34, the optical element 10 can function as a shutter by changing the adjustment chamber 32 between a state where light can be transmitted and a state where light is shielded.
Therefore, also in the second embodiment, similarly to the first embodiment, the moving speed of the first liquid 14 can be increased, which is advantageous in improving the response of the optical element 10.

(Third embodiment)
Next, a third embodiment will be described.
The third embodiment is different from the first embodiment in that four evacuation chambers 34 are provided, and the first liquid 14 is divided into four and moved between the adjustment chamber 32 and each evacuation chamber 34. ing.
FIG. 14 and FIG. 15 are diagrams for explaining the operation of the optical element 10 according to the third embodiment, and the optical element 10 is viewed in plan.
As shown in FIG. 14, the four evacuation chambers 34 are arranged around the adjustment chamber 32 at the same pitch (at a pitch of 90 degrees) around the adjustment chamber 32 as viewed from the light transmitting direction. ing.
In other words, the storage chamber 30 has a cross shape when viewed from the direction in which the light is transmitted, and the adjustment chamber 32 is located at the center of the cross shape, and two of the four retraction chambers 34 are located in the adjustment chamber 32. The remaining two retracting chambers 34 are provided on a straight line extending in a direction orthogonal to the direction in which the light is transmitted on both sides, and the remaining two retreat chambers 34 are in the direction orthogonal to the direction in which the light is transmitted on both sides of the adjustment chamber 32 Are provided on another straight line perpendicular to the line.
The adjustment chamber 32 and the four retracting chambers 34 include a first end face wall (not shown) and a second end face wall 26 that face each other in the light transmitting direction.
The four evacuation chambers 34 further include a side wall 28 that connects the first and second end face walls, and each evacuation chamber 34 is between the first and second end face walls except for a portion communicating with the adjustment chamber 32. Is partitioned by a side wall 28.
The side wall 28 of the adjacent evacuation chamber 34 forms a corner portion 2802 that extends between the first and second end surface walls at a location communicating with the adjustment chamber 32. In this embodiment, the corner 2802 has a right angle.
In the third embodiment, as in the first embodiment, the first liquid 14 and the second liquid 16 have substantially the same specific gravity, and the transmittance of the first liquid 14 is the second. The second liquid 16 is sealed in the storage chamber 30 so as to surround the first liquid 14.

As shown in FIG. 14, the first electrode 18 is provided on the first end face walls of the adjustment chamber 32 and the four retraction chambers 34, and the first electrode 18 is connected to the adjustment chamber 32 and the four retraction chambers 34. It is comprised by the single electrode member 36 extended over the 1st end surface wall. In the present embodiment, the electrode member 36 is formed in a cross shape having a contour that is slightly smaller than the contour of the first end face wall.
The second electrode 20 is provided on the second end wall 26 of the adjustment chamber 32 and the four retracting chambers 34. In the present embodiment, the second electrode 20 is provided in the same shape and separated from each other. The large five electrode members 50A, 50B, 50C, 50D, and 50E are configured. One of the five electrode members 50A is provided on the second end face wall 26 of the adjustment chamber 32, and the remaining four electrode members. 50B, 50C, 50D, and 50E are provided on the second end face walls 26 of the four retracting chambers 34, respectively.
Edge portions where the central electrode member 50A and the four electrode members 50B, 50C, 50D, and 50E are adjacent to each other are formed as uneven portions 2010 that extend in a direction orthogonal to the extending direction of the straight line, and are adjacent to each other. The electrode members are arranged in a state where the concavo-convex portions 2010 are parallel to each other and face each other with a gap.

  The voltage applying unit 22 supplies a ground potential to the first electrode 18 and can selectively apply the voltage E to each of the five electrode members 50A, 50B, 50C, 50D, and 50E of the second electrode 20. It is configured.

Next, the operation of the optical element 10 will be described.
First, an operation when the adjustment chamber 32 of the optical element 10 changes from a state of shielding light to a state of transmitting light will be described.
In the initial state, as shown in FIG. 14, the first liquid 14 is placed at a position sandwiched between the electrode member 36 of the first electrode 18 and the center electrode member 50 </ b> A of the second electrode 20 in the adjustment chamber 32. positioned.
In this state, the voltage applying unit 22 applies the voltage E to the central electrode member 50A, and the remaining four electrode members 50B, 50C, 50D, and 50E are in an open state (or a state in which a ground potential is applied).
Therefore, the electric field generated by the voltage E applied to the first electrode 18 and the central electrode member 50A acts on the first liquid 14 located at the position facing the central electrode member 50A, thereby The liquid 14 is held in its position without moving, and as a result, most of the first liquid 14 faces the central electrode member 50A, and a part of the first liquid 14 is adjacent to the four It faces the electrode members 50B, 50C, 50D, and 50E.
In this state, incident light traveling toward the adjustment chamber 32 is shielded by the first liquid 14 located in the adjustment chamber 32 and having a low transmittance.

Next, as shown in FIG. 15, the voltage applying means 22 opens the central electrode member 50A (or a state in which a ground potential is applied), and supplies the voltage E to the remaining four electrode members 50B, 50C, 50D, and 50E. That is, that is, the position of voltage application to the second electrode 20 is changed to the remaining four electrode members 50B, 50C, 50D, and 50E.
Then, the electric field generated by the voltage E applied to the first electrode 18 and the four electrode members 50B, 50C, 50D, and 50E acts on the first liquid 14 located at the position facing the central electrode member 50A. Thus, in a state where the first liquid 14 is surrounded by the second liquid 16, the first liquid 14 is divided into four and each moves toward the four retreat chambers 34.
Thus, the four divided first liquids 14 are accommodated in the four retreat chambers 34, respectively.
At this time, most of the divided first liquid 14 faces the four electrode members 50B, 50C, 50D and 50E, and a part of the first liquid 14 faces the adjacent central electrode member 50A. .
In this state, the incident light traveling toward the adjustment chamber 32 is transmitted through the second liquid 16 located in the adjustment chamber 32 and having a high transmittance.

Next, the operation when the adjustment chamber 32 of the optical element 10 changes from a state of transmitting light to a state of shielding, contrary to the above, will be described.
As shown in FIG. 15, the voltage application means 22 applies the voltage E to the central electrode member 50A in a state where the divided first liquids 14 are respectively stored in the four retreat chambers 34, and the remaining four liquids The electrode members 50B, 50C, 50D, and 50E are in an open state (or a state in which a ground potential is applied).
Then, the electric field generated by the voltage E applied to the first electrode 18 and the central electrode member 50A acts on the first liquid 14 located at the positions facing the four electrode members 50B, 50C, 50D, and 50E, respectively. As a result, the divided first liquid 14 moves from the retreat chambers 34 toward the adjustment chambers 32 in a state in which the first liquid 14 is surrounded by the second liquid 16.
Thereby, as shown in FIG. 14, the first liquid 14 that has been divided into four is accommodated in the adjustment chamber 32 and united.
Accordingly, the electric field generated by the voltage E applied to the first electrode 18 and the central electrode member 50A acts on the first liquid 14, so that the first liquid 14 reaches the central electrode member 50A without moving. As a result, most of the first liquid 14 faces the center electrode member 50A, and a part of the first liquid 14 is adjacent to the four electrode members 50B, 50C, 50D. , 50E.
In this state, incident light traveling toward the adjustment chamber 32 is shielded by the first liquid 14 located in the adjustment chamber 32 and having a low transmittance.

Similarly to the first embodiment, the optical element 10 of the third embodiment also changes the position of voltage application by the voltage application means 22 to divide the first liquid 14 and adjust the adjustment chamber 32. The optical element 10 can function as a shutter by moving the adjustment chamber 32 between a state where light can be transmitted and a state where light is shielded by moving between the four retreat chambers 34.
In particular, in the third embodiment, since the first liquid 14 is divided into four parts, the moving speed of the first liquid 14 can be further increased compared to the first embodiment, and the response of the optical element 10 can be increased. This is more advantageous for improving the performance.
In the third embodiment, since the four corners 2802 face the storage chamber 30, the first liquid 14 stored in the adjustment chamber 32 is divided and moved to each retreat chamber 34. At this time, since the first liquid 14 is smoothly divided by being separated at each corner 2802, it is more advantageous in increasing the moving speed of the first liquid 14.
The first liquid 14 can be divided and moved even if the corner 2802 is not formed in the storage chamber 30, but when the corner 2802 is formed, the corner 2802 is not formed. Compared to the above, it is advantageous in increasing the moving speed of the first liquid 14 as described above.

(Fourth embodiment)
Next, a fourth embodiment will be described.
The fourth embodiment is a modification of the third embodiment, and the configuration is the same as that of the third embodiment, but the operation when dividing the first liquid 14 into two is the third. This is different from the embodiment.
FIGS. 16A, 16B, and 16C are operation explanatory views of the optical element 10 according to the fourth embodiment.
As shown in FIG. 16A, the voltage application means 22 applies a voltage E to the electrode members 50B and 50D of the two opposing retreat chambers 34, and the electrode members 50C and 50E of the remaining two retreat chambers 34 and The central electrode member 50A is in an open state (or a state in which a ground potential is applied), and the first liquid 14 is divided into two and accommodated in two opposing retreat chambers 34.
In this state, the incident light traveling toward the adjustment chamber 32 is transmitted through the second liquid 16 located in the adjustment chamber 32 and having a high transmittance.

Next, the voltage E is applied to the central electrode member 50A by the voltage applying means 22, and the remaining four electrode members 50B, 50C, 50D, and 50E are opened (or a ground potential is applied).
Then, as shown in FIG. 16B, the first liquid 14 accommodated in the two opposing retreat chambers 34 is adjusted from each retreat chamber 34 with the second liquid 16 surrounded by the periphery. It moves toward the chamber 32 and the first liquid 14 is accommodated in the adjustment chamber 32 and united.
In this state, incident light traveling toward the adjustment chamber 32 is shielded by the first liquid 14 located in the adjustment chamber 32 and having a low transmittance.
At this time, since the two first liquids 14 moving in the directions approaching each other are merged, the force acting on each first liquid 14 at that time indicates a two-dot chain line in FIG. As described above, the combined first liquid 14 is stretched along a straight line perpendicular to a straight line connecting the two opposing retreat chambers 34, that is, along a straight line connecting the remaining two retreat chambers 34. Deform.
In a state where this deformation occurs, as shown in FIG. 16C, voltage E is applied to the electrode members 50C and 50E of the remaining two evacuation chambers 34 by the voltage application means 22, and the two evacuation chambers 34 are applied. When the electrode members 50B and 50D and the central electrode member 50A are opened (or a ground potential is applied), the first liquid 14 is applied to the electrode members 50C and 50E of the remaining two escape chambers 34. The two are separated into two by the action of the electric field by the voltage E, and are moved and accommodated in the remaining two retreat chambers 34, respectively.
In this state, the incident light traveling toward the adjustment chamber 32 is transmitted through the second liquid 16 located in the adjustment chamber 32 and having a high transmittance.

  According to the fourth embodiment, after the first liquid 14 moves from the two retreat chambers 34 facing each other to the adjustment chamber 32 to be combined and deformed, the remaining two retreat chambers located in the deformed direction 34, since the first liquid 14 is moved to the adjustment chamber 32 from the two opposing retreat chambers 34, the first liquid 14 is quickly removed from the two remaining retreat chambers 34. Since it can be moved to the chamber 34, the time during which the first liquid 14 stays in the adjustment chamber 32 can be shortened, which is advantageous in speeding up the optical path shielding operation by the optical element 10.

(Fifth embodiment)
Next, a fifth embodiment will be described.
The fifth embodiment is a modification of the third embodiment, in which eight retreat chambers 34 are provided and the first liquid 14 is divided into eight.
17A and 17B are diagrams for explaining the operation of the optical element 10 according to the fifth embodiment, and FIG. 18 is a plan view of the first electrode 18.
As shown in FIG. 17A, the optical element 10 includes a storage chamber 30, and the storage chamber 30 includes an adjustment chamber 32, and eight retraction chambers 34 arranged at equal intervals on the outer periphery of the adjustment chamber 32. It has.
The adjustment chamber 32 and the eight evacuation chambers 34 include a first end face wall (not shown) and a second end face wall 26 that face each other in the light transmitting direction.
The eight evacuation chambers 34 further include a side wall 28 connecting the first and second end surface walls, and each evacuation chamber 34 is located between the first and second end surface walls except for a portion communicating with the adjustment chamber 32. Is partitioned by a side wall 28.
The side wall 28 of the adjacent evacuation chamber 34 forms a corner portion 2802 extending between the first and second end surface walls at a location communicating with the adjustment chamber 32. In the present embodiment, the corner portion 2802 is formed. Has an acute angle.
In the fifth embodiment, as in the first embodiment, the first liquid 14 and the second liquid 16 have substantially the same specific gravity, and the transmittance of the first liquid 14 is the second. The second liquid 16 is sealed in the storage chamber 30 so as to surround the first liquid 14.

As shown in FIG. 18, the first electrode 18 is provided on the first end face walls of the adjustment chamber 32 and the eight escape chambers 34, and the first electrode 18 includes the adjustment chamber 32 and the eight escape chambers 34. It is comprised by the single electrode member 36 extended over the 1st end surface wall. In the present embodiment, the electrode member 36 is formed with a contour that is slightly smaller than the contour of the first end face wall.
As shown in FIG. 17A, the second electrode 20 is provided on the second end wall 26 of the adjustment chamber 32 and the eight retracting chambers 34. In the present embodiment, the second electrode 20 is Each of the electrode members 50F is provided on the second end face wall 26 of the adjustment chamber 32, and the remaining eight electrode members 50G have the same shape and size. Formed on the second end wall 26 of each of the eight evacuation chambers 34.

  The voltage application means is configured to supply a ground potential to the first electrode 18 and selectively apply the voltage E to each of the nine electrode members 50F and 50G of the second electrode 20.

Next, the operation of the optical element 10 will be described.
First, an operation when the adjustment chamber 32 of the optical element 10 changes from a state of shielding light to a state of transmitting light will be described.
In the initial state, as shown in FIG. 17A, the first liquid 14 is sandwiched between the electrode member 36 of the first electrode 18 and the electrode member 50F at the center of the second electrode 20 in the adjustment chamber 32. It is located in the place.
In this state, the voltage applying means 22 applies the voltage E to the central electrode member 50F, and the remaining eight electrode members 50G are in an open state (or a state in which a ground potential is applied).
Accordingly, the electric field generated by the voltage E applied to the first electrode 18 and the central electrode member 50F acts on the first liquid 14 located at the position facing the central electrode member 50F, so that the first The liquid 14 is held in its position without moving, and as a result, most of the first liquid 14 faces the central electrode member 50F, and a part of the first liquid 14 is adjacent to the eight It faces the electrode member 50G.
In this state, incident light traveling toward the adjustment chamber 32 is shielded by the first liquid 14 located in the adjustment chamber 32 and having a low transmittance.

Next, when the voltage application means 22 opens the central electrode member 50F (or a state in which a ground potential is applied) and applies the voltage E to the remaining eight electrode members 50G, that is, to the second electrode 20 The place where voltage is applied is changed to the remaining eight electrode members 50G.
Then, the electric field generated by the voltage E applied to the first electrode 18 and the eight electrode members 50G acts on the first liquid 14 located at the position facing the central electrode member 50F, so that FIG. As shown in B), in a state where the first liquid 14 is surrounded by the second liquid 16, the first liquid 14 is divided into eight and each moves toward the eight retreat chambers 34.
As a result, the first liquid 14 divided into eight is stored in the eight retreat chambers 34, respectively.
At this time, most of the divided first liquid 14 faces each of the eight electrode members 50G, and a part of the first liquid 14 faces the adjacent central electrode member 50F.
In this state, the incident light traveling toward the adjustment chamber 32 is transmitted through the second liquid 16 located in the adjustment chamber 32 and having a high transmittance.

Next, the operation when the adjustment chamber 32 of the optical element 10 changes from a state of transmitting light to a state of shielding, contrary to the above, will be described.
As shown in FIG. 17B, the voltage application means 22 applies the voltage E to the central electrode member 50F in a state where the divided first liquid 14 is accommodated in the eight retreat chambers 34, respectively. The remaining eight electrode members 50G are opened (or a ground potential is applied).
Then, the electric field due to the voltage E applied to the first electrode 18 and the central electrode member 50F acts on the first liquid 14 located at the positions facing the eight electrode members 50G, respectively, thereby being divided. In addition, the first liquid 14 moves from the retreat chamber 34 toward the adjustment chamber 32 in a state where the first liquid 14 is surrounded by the second liquid 16.
Thereby, as shown in FIG. 17A, the first liquid 14 divided into eight is accommodated in the adjustment chamber 32 and united.
Accordingly, the electric field generated by the voltage E applied to the first electrode 18 and the central electrode member 50F acts on the first liquid 14, so that the first liquid 14 reaches the central electrode member 50F without moving. As a result, most of the first liquid 14 faces the central electrode member 50F, and a part of the first liquid 14 faces eight adjacent electrode members 50G. .
In this state, incident light traveling toward the adjustment chamber 32 is shielded by the first liquid 14 located in the adjustment chamber 32 and having a low transmittance.

Similarly to the first embodiment, the optical element 10 according to the fifth embodiment also divides the first liquid 14 and moves it between the adjustment chamber 32 and the eight retraction chambers 34. By changing the adjustment chamber 32 between a state where light can be transmitted and a state where light is blocked, the optical element 10 can function as a shutter.
Particularly in the fifth embodiment, since the first liquid 14 is divided into eight, the first embodiment in which the first liquid 14 is divided into two or the third embodiment in which the first liquid 14 is divided into four. Compared to the form, the moving speed of the first liquid 14 can be further increased, which is more advantageous in improving the response of the optical element 10.
In addition, since the eight corners 2802 face the storage chamber 30, the first liquid 14 stored in the adjustment chamber 32 is divided and moved to each retreat chamber 34, as in the third embodiment. In doing so, since the first liquid 14 is smoothly divided by being separated at each corner 2802, it is more advantageous in increasing the moving speed of the first liquid 14.

(Sixth embodiment)
Next, a sixth embodiment will be described.
The sixth embodiment improves the responsiveness by dividing the first liquid 14 into two stages and dividing the first liquid 14 into one stage when combining the first liquid 14. Is intended.
19 to 21 are explanatory diagrams of the operation of the optical element 10 according to the sixth embodiment.
As shown in FIG. 19, the optical element 10 includes a container 12, a first liquid 14, a second liquid 16, a first electrode 18 and a second electrode 20, and a voltage applying unit 22. It consists of
The container 12 includes a first end face wall (not shown), a second end face wall 26, and a first end face wall 24 and a second end face wall 26 that extend in parallel with each other in a direction in which light is transmitted. And a side wall 28 for connecting the first and second end face walls and the side wall 28 to each other.
The first electrode 18 is provided on the first end wall 24, and the second electrode 20 is provided on the second end wall 26.
The second electrode 20 includes a central electrode member 52 and a plurality of peripheral electrode members 54 provided around the central electrode member 52. In the present embodiment, the peripheral electrode member 54 is the center electrode member 52. Three are provided on each side. The three peripheral electrode members 54 are composed of a first peripheral electrode member 54A located at the center of the three peripheral electrode members 54 and two second peripheral electrode members 54B sandwiching the first peripheral electrode member 54.
The first electrode 18 includes a single electrode member 56 that faces the central electrode member 52 and the plurality of surrounding electrode members 54.

  The voltage applying means 22 is configured to supply a ground potential to the first electrode 18 and to selectively apply a voltage E to each of the central electrode member 52 and the six surrounding electrode members 54 of the second electrode 20. Has been.

Next, the operation of the optical element 10 will be described.
First, an operation when the accommodation chamber 30 of the optical element 10 changes from a state of shielding light to a state of transmitting light will be described.
In the initial state, as shown in FIG. 19, the first liquid 14 is positioned at a location sandwiched between the electrode member 56 of the first electrode 18 and the central electrode member 52 of the second electrode 20 in the storage chamber 30. is doing.
In this state, the voltage applying means 22 applies the voltage E to the central electrode member 52, and the remaining six electrode members 54 are in an open state (or a state in which a ground potential is applied).
Therefore, the electric field generated by the voltage E applied to the first electrode 18 and the central electrode member 52 acts on the first liquid 14 positioned at the position facing the central electrode member 52, thereby causing the first liquid 14. Is held in that position without moving, and as a result, most of the first liquid 14 faces the central electrode member 52, and six surrounding electrode members to which a part of the first liquid 14 is adjacent are held. It is facing 54.
In this state, incident light traveling toward the storage chamber 30 is shielded by the first liquid 14 located in the storage chamber 30 and having a low transmittance.

Next, as shown in FIG. 20, the voltage applying means 22 opens the central electrode member 52 and the four second peripheral electrode members 54B (or a state where a ground potential is applied), and the two first peripheral electrode members. A voltage E is applied to 54A. That is, the location of voltage application to the second electrode 20 is changed to the first peripheral electrode member 54A.
Then, the electric field due to the voltage E applied to the first electrode 18 and the two first surrounding electrode members 54A acts on the first liquid 14 located at the position facing the central electrode member 52, so that the first In a state in which one liquid 14 is surrounded by the second liquid 16, the first liquid 14 is divided into two parts and each moves toward the two first peripheral electrode members 54A.
Accordingly, the first liquid 14 divided into two is held in a state of facing the two first peripheral electrode members 54A.
At this time, most of the divided first liquid 14 faces each of the first peripheral electrode members 54A, and a part of the first liquid 14 faces the adjacent central electrode member 52 and second peripheral electrode member 54B. Yes.

Next, as shown in FIG. 21, the voltage applying means 22 opens the central electrode member 52 and the two first surrounding electrode members 54A (or a state in which a ground potential is applied), and the four second surrounding electrode members. A voltage E is applied to 54B. That is, the location of voltage application to the second electrode 20 is changed to the second peripheral electrode member 54B.
Then, the electric field due to the voltage E applied to the first electrode 18 and the four second peripheral electrode members 54B acts on the first liquid 14 located at the position facing each first peripheral electrode member 54A. Thus, in a state where the first liquid 14 is surrounded by the second liquid 16, the first liquid 14 is divided into two parts and each moves toward the second peripheral electrode member 54B.
Accordingly, the first liquid 14 divided into four parts is held in a state of facing the four second peripheral electrode members 54B.
At this time, most of the divided first liquid 14 faces each of the second peripheral electrode members 54B, and a part of the first liquid 14 faces the adjacent central electrode member 52 and first peripheral electrode member 54A. Yes. In this state, the incident light traveling toward the storage chamber 30 passes through the second liquid 16 located in the storage chamber 30 and having a high transmittance.

Next, contrary to the above description, an operation in the case where the accommodation chamber 30 of the optical element 10 changes from a light transmitting state to a shielding state will be described.
As shown in FIG. 21, the voltage applying means 22 applies the voltage E to the central electrode member 52 in a state where the first liquid 14 divided into four parts is located at the positions facing the four second peripheral electrode members 54B. And the two first peripheral electrode members 54A and the four second peripheral electrode members 54B are all opened (or a ground potential is applied).
Then, the electric field due to the voltage E applied to the first electrode 18 and the central electrode member 52 acts on each of the first liquids 14 located at the positions facing the four second peripheral electrode members 54B. The divided first liquid 14 moves toward the central electrode member 52 in a state in which the first liquid 14 is surrounded by the second liquid 16.
Thereby, as shown in FIG. 19, the first liquid 14 that has been divided into four is united on the central electrode member 52.
Accordingly, the electric field generated by the voltage E applied to the first electrode 18 and the central electrode member 52 acts on the first liquid 14, so that the first liquid 14 faces the central electrode member 52 without moving. As a result, most of the first liquid 14 faces the central electrode member 52, and a part of the first liquid 14 is adjacent to the first peripheral electrode member 54A and the second peripheral electrode member. It faces 54B.
In this state, incident light traveling toward the storage chamber 30 is shielded by the first liquid 14 located in the storage chamber 30 and having a low transmittance.

Similarly to the first embodiment, the optical element 10 according to the sixth embodiment also changes the position of voltage application by the voltage application means 22 to divide the first liquid 14 and divide the central electrode member 52. And the surrounding electrode member 54, the optical element 10 can be caused to function as a shutter by changing the accommodation chamber 30 between a state where light can be transmitted and a state where light is shielded.
In particular, in the sixth embodiment, the first liquid 14 is once divided into two, and then the two divided first liquids 14 are respectively divided into two. Therefore, a voltage sufficient to divide the first liquid 14 into two is obtained. What is necessary is just to apply to the 1st surrounding electrode member 54A and the 2nd surrounding electrode member 54B, and there is little voltage compared with the case where the 1st liquid 14 is divided | segmented into 4 simultaneously, and it is advantageous in attaining power saving. It becomes.
Further, when the first divided liquid 14 divided into four is moved to the central electrode member 54A and united into one, the volume and mass are divided into two because the first liquid 14 is divided into four. Since the volume and mass of the first liquid 14 are smaller than the case where the first liquid 14 is present, the moving speed of the first liquid 14 can be further increased, which is more advantageous for improving the response of the optical element 10.

In the embodiment, the case where the first liquid 14 is divided into two, four, or eight by providing two, four, or eight electrode members has been described. Is not limited thereto. It goes without saying that the first liquid 14 may be divided by providing two or more even or even plural electrode members.
In the embodiment, the case where the optical element 10 is configured as a shutter has been described, but it is needless to say that the optical element 10 may be configured as an ND filter (NeutralDensityFilter). In this case, for example, one transmittance of the first liquid 14 and the second liquid 16 is set to a value that functions as an ND filter, and the other transmittance of the first liquid 14 and the second liquid 16 is set. May be set to 100%.
In addition, a plurality of types of ND filters having different transmittances (light attenuation rates) are configured by the optical element 10, and if the plurality of optical elements 10 are arranged in layers on the optical axis of the imaging apparatus 100, the light attenuation rate. It is possible to configure an ND filter that can change the number of the NDs into a plurality of types.
In the present embodiment, the case where the imaging apparatus 100 is a digital still camera or a video camera has been described. However, the present invention describes a mobile phone with a camera, a PDA (personal digital assistant) with a camera, and a notebook with a camera. It can be widely applied to various imaging devices such as personal computers.

  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, 30... Storage chamber, 32.

Claims (16)

A container having a storage chamber;
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,
An optical element that moves the first liquid in the second liquid in the storage chamber by changing a position of voltage application to the first and second electrodes by the voltage applying means,
The accommodation chamber can accommodate an adjustment chamber for adjusting the amount of transmitted light depending on the presence or absence of the first liquid, and the first liquid retreated from the adjustment chamber in communication with the adjustment chamber. A plurality of evacuation chambers,
The adjustment chamber and the plurality of evacuation chambers include first and second end face walls facing each other in a direction in which the light is transmitted,
The first electrode is provided on one end face wall of the first and second end face walls of the adjustment chamber and the plurality of evacuation chambers, and the second electrode is the first and second end walls. Provided on the other end face wall of the end face walls,
An optical element.   The optical element according to claim 1, wherein the escape chamber communicates with the adjustment chamber from a direction orthogonal to a direction in which the light is transmitted.   2. The optical element according to claim 1, wherein the escape chamber is arranged around the adjustment chamber as viewed from a direction in which the light is transmitted.   2. The optical element according to claim 1, wherein the retracting chambers are arranged at the same pitch along the circumferential direction around the adjustment chamber as viewed from the light transmitting direction.   The two evacuation chambers are provided, and the two evacuation chambers are provided on a straight line extending in a direction orthogonal to a direction in which the light is transmitted on both sides of the adjustment chamber. The optical element according to 1.   Four of the four evacuation chambers are provided, and two of the four evacuation chambers are provided on a straight line extending in a direction perpendicular to the direction in which the light is transmitted on both sides of the adjustment chamber, and the remaining two 2. The optical element according to claim 1, wherein the retreat chamber is provided on another straight line orthogonal to the straight line in a direction orthogonal to the light transmission direction on both sides of the adjustment chamber. Each of the retreat chambers is partitioned by a side wall between the first and second end wall except for a portion communicating with the adjustment chamber.
The side walls of the adjacent evacuation chambers form corners extending between the first and second end surface walls at locations communicating with the adjustment chamber.
The optical element according to claim 1. The first electrode is composed of a single electrode member extending over one end face wall of the first and second end face walls of the adjustment chamber and the plurality of retreat chambers,
The second electrode is composed of a plurality of electrode members provided separately from the other end surface walls of the first and second end surface walls of the adjustment chamber and the plurality of retreat chambers. ,
The optical element according to claim 1. An uneven portion is formed to extend in a direction orthogonal to the extending direction of the straight line at a location where the plurality of electrode members of the second electrode are adjacent to each other,
The adjacent electrode members are arranged in a state where the uneven portions face each other with a gap between them,
The optical element according to claim 8. An uneven portion is formed to extend in a direction orthogonal to the extending direction of the straight line at a location where the plurality of electrode members of the second electrode are adjacent to each other,
The adjacent electrode members are arranged in a state where the uneven portions face each other with a gap between them,
At the center in the extending direction of the concavo-convex portion of the electrode member provided on the end surface wall of the adjustment chamber, a convex projecting greatly toward the end surface wall side of the retracting chamber than the other convex portions constituting the concavo-convex portion. Part is provided,
At the center in the extending direction of the concavo-convex portion of the electrode member provided on the end face wall of each evacuation chamber, there is a concave portion that is largely recessed toward the center side of the evacuation chamber than other concave portions constituting the concavo-convex portion Provided,
The convex part is arranged in a state facing the concave part with a gap,
The optical element according to claim 8. A container having a storage chamber;
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,
An optical element that moves the first liquid in the second liquid in the storage chamber by changing a position of voltage application to the first and second electrodes by the voltage applying means,
The storage chamber includes first and second end face walls facing each other in a direction in which light is transmitted,
The first electrode is provided on one end wall of the first and second end walls, and the second electrode is the other end wall of the first and second end walls. Provided in
The second electrode is composed of a central electrode member and a plurality of peripheral electrode members provided around the central electrode member,
The first electrode is composed of a single electrode member facing the central electrode member and the plurality of surrounding electrode members.
An optical element.   12. The optical element according to claim 11, wherein three of the peripheral electrode members are provided on each side of the central electrode member.   The optical element according to claim 1, wherein the transmittance of the first liquid is lower than the transmittance of the other of the second liquid.   The optical element according to claim 1, wherein the transmittance of the second liquid is formed to be lower than the transmittance of the first liquid. A photographic optical system that guides the subject image;
An image sensor provided on the optical axis of the imaging optical system;
An optical element provided in front of the imaging element on the optical axis,
The optical element is
A container having a storage chamber;
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,
Moving the first liquid in the second liquid in the storage chamber by changing the position of voltage application to the first and second electrodes by the voltage applying means;
The accommodation chamber can accommodate an adjustment chamber for adjusting the amount of transmitted light depending on the presence or absence of the first liquid, and the first liquid retreated from the adjustment chamber in communication with the adjustment chamber. A plurality of evacuation chambers,
The adjustment chamber and the plurality of evacuation chambers include first and second end face walls facing each other in a direction in which the light is transmitted,
The first electrode is provided on one end face wall of the first and second end face walls of the adjustment chamber and the plurality of evacuation chambers, and the second electrode is the first and second end walls. Provided on the other end face wall of the end face walls,
An imaging apparatus characterized by that. A photographic optical system that guides the subject image;
An image sensor provided on the optical axis of the imaging optical system;
An optical element provided in front of the imaging element on the optical axis,
The optical element is
A container having a storage chamber;
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,
Moving the first liquid in the second liquid in the storage chamber by changing the position of voltage application to the first and second electrodes by the voltage applying means;
The storage chamber includes first and second end face walls facing each other in a direction in which light is transmitted,
The first electrode is provided on one end wall of the first and second end walls, and the second electrode is the other end wall of the first and second end walls. Provided in
The second electrode is composed of a central electrode member and a plurality of peripheral electrode members provided around the central electrode member,
The first electrode is composed of a single electrode member facing the central electrode member and the plurality of surrounding electrode members.
An imaging apparatus characterized by that.

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