JP2002162506A - Optical element, optical device and photographing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart an optical element having the function of absorbing volume change of liquid accompanying temperature change, without enlarging the size of the optical element. SOLUTION: In an optical element 201 constructed by containing the liquids 121, 122 in a liquid chamber formed inside a container, a space 152 partitioned off from the liquid chamber with film-shaped flexible members 150, 151, is formed inside the thickness of a wall part 105 of the container.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element using a liquid and an optical device having the optical element.

[0002]

2. Description of the Related Art Conventionally, various proposals have been made to achieve variable focus without mechanically moving a lens.

[0003] For example, Japanese Patent Application Laid-Open No. 11-133210 discloses an optical element in which a transparent liquid is sealed in a closed container and a potential difference is applied between a first electrode provided in the container and a conductive elastic plate. Proposed.

In this optical element, by applying a potential difference between the first electrode and the conductive elastic plate, a suction force due to Coulomb force is generated to reduce the distance between the two, and the transparent liquid that is rejected from the distance between the two. With the volume of the transparent elastic plate, the central part of the transparent elastic plate is deformed in a convex shape facing the transparent liquid, and a convex lens is formed by the transparent elastic plate deformed in the convex shape, the transparent plate, and the transparent liquid filling the space between them. Let it. The power of the convex lens is changed by changing the potential difference, thereby forming a variable-focus optical element.

On the other hand, a variable focus lens using the electrowetting effect (electrocapillarity) is disclosed in International Patent No.
No./18456. In this varifocal lens, electric energy can be directly used to change the shape of the lens formed by the interface between the first transparent liquid and the second transparent liquid sealed in a closed container. Can be changed to a variable focus without being moved.
The operation principle will be described with reference to FIGS.

FIGS. 15 and 16 are cross-sectional views showing the structure of the optical element. Here, the optical axis 123
Are described as extending in the vertical direction.

In FIG. 1, reference numeral 101 denotes the entire optical element. Reference numeral 102 denotes a transparent acrylic transparent substrate provided with a concave portion in the center. On the upper surface of the transparent substrate 102, a transparent electrode 103 having a predetermined surface resistivity, which is a resistor on a thin film, is formed. On the upper surface, a transparent acrylic insulating layer 104 is provided in close contact. Note that the transparent electrode 103 is provided with a plurality of connecting portions as described later, but is not shown in FIGS. 15 and 16.

The insulating layer 104 is formed by dropping a replica resin at the center of the transparent electrode 103 and pressing it with a glass plate to smooth the surface, and then irradiating with UV to cure. On the upper surface of the insulating layer 104, a cylindrical container body 105 having a light-shielding property is bonded and fixed, and on the upper surface, a transparent acrylic upper cover 106 is bonded and fixed.

Further, on the upper surface of the upper cover 106, an aperture plate 107 having an opening having a diameter D3 in the center is disposed.

In the above configuration, a closed space of a predetermined volume surrounded by the insulating layer 104, the container body 105 and the upper cover 106, that is, a container as a housing having a liquid chamber is formed. The wall surface of the liquid chamber is subjected to the following surface treatment.

First, a water-repellent treatment agent is applied to the center upper surface of the insulating layer 104 within a range of a diameter D1 to form a water-repellent film 111. As the water repellent, a fluorine compound or the like is suitable.

A hydrophilic treatment agent is applied to a region outside the diameter D1 of the upper surface of the insulating layer 104, and the hydrophilic film 112
Are formed. As the hydrophilic agent, a surfactant, a hydrophilic polymer and the like are preferable.

On the other hand, the lower surface of the upper cover 106 has a diameter D
2, a hydrophilic treatment is performed, and a hydrophilic film 113 having the same properties as the hydrophilic film 112 is formed.

All the components described so far have rotationally symmetric shapes with respect to the optical axis 123.

A hole is formed in a part of the container body 105, into which a rod-like electrode 125 is inserted. Rod electrode 1
The gap between the hole 25 and the hole is sealed with an adhesive, and the tightness of the liquid chamber is maintained.

A power supply circuit 126 is connected to each connecting portion (not shown) of the transparent electrode 103 and the rod electrode 125.
By operating the switch 127, a predetermined voltage can be applied between both electrodes.

The liquid chamber in the container having the above-described structure is filled with the following two types of liquids. First, the insulating layer 104
The second liquid 122 is dropped by a predetermined amount on the upper water-repellent film 111. The second liquid 122 is a colorless and transparent silicone oil having a specific gravity of 1.06 and a refractive index of 1.49 at room temperature.

The remaining space in the liquid chamber is filled with the first liquid 121. The first liquid 121 is obtained by mixing water and ethyl alcohol at a predetermined ratio and further adding a predetermined amount of salt, and has a specific gravity of 1.06 and a refractive index of 1.38 at room temperature.
(A conductive or polar liquid).

That is, the first and second liquids 121,
For 122, liquids having the same specific gravity, different refractive indices, and being immiscible (insoluble) with each other are selected. The two liquids 121 and 122 form an interface 124 and exist independently without being mixed.

Next, the shape of the interface 124 will be described. First, as shown in FIG. 15, when no voltage is applied between the first liquid 121 and the transparent electrode 103, the interface 1
The shape of 24 is the interfacial tension between the two liquids 121 and 122, the interfacial tension between the first liquid 121 and the water-repellent film 111 or the hydrophilic film 112 on the insulating layer 104, and the second liquid 122 and the surface tension on the insulating layer 104. It is determined by the interfacial tension with the water-repellent film 111 or the hydrophilic film 112 and the volume of the second liquid 122.

In the present optical element 101, the second liquid 122
The material is selected so that the interfacial tension between the silicone oil, which is the material described above, and the water-repellent film 111 is relatively small. That is, since the wettability between the two materials is high, the outer edge of the lenticular droplet formed by the second liquid 122 has a tendency to spread, and becomes stable when the outer edge coincides with the application area of the water-repellent film 111. That is, the diameter A1 of the lens bottom surface formed by the second liquid 122 is equal to the diameter D1 of the water-repellent film 111.

Further, since the specific gravities of the two liquids 121 and 122 are equal to each other as described above, the two liquids 121 and 122 have the same specific gravity.
No apparent gravity acts on 122. Therefore, the interface 124 becomes a spherical surface, and its radius of curvature and height h1 are determined by the volume of the second liquid 122. The thickness of the first liquid 121 on the optical axis is t1.

On the other hand, when the switch 127 is closed and a voltage is applied between the first liquid 121 and the transparent electrode 103,
The first liquid 12 by the electrowetting effect
1 and the hydrophilic film 112, the first liquid 1
21 penetrates the boundary between the hydrophilic film 112 and the water-repellent film 111 and enters the water-repellent film 111.

As a result, as shown in FIG. 16, the diameter of the bottom surface of the lens formed by the second liquid 122 decreases from A1 to A2, and the height increases from h1 to h2. The thickness of the first liquid 121 on the optical axis is t2.

As described above, by applying the voltage to the first liquid 121, the balance of the interfacial tension between the two liquids changes, and the shape of the interface 124 between the two liquids 121 and 122 changes. For this reason, an optical element that can freely change the shape of the interface 124 by controlling the voltage of the power supply circuit 126 can be realized.

Also, the first and second liquids 121 and 12
Since the lenses 2 have different refractive indices, power as an optical lens is applied, and the optical element 101 becomes a lens whose focal length is variable due to a change in the shape of the interface 124.

Further, the interface 12 shown in FIG.
4 has a shorter radius of curvature, so that the optical element 101 in the state shown in FIG. 16 has a shorter focal length than the state in FIG.

The principle of deformation of the two-liquid interface by the electrowetting is disclosed in International Patent Publication No. 99/18456, and the interface 124 is positioned at positions A and A of the two-liquid interface described in FIG. B.

FIG. 17 shows the relationship between the output voltage of the power supply circuit 126 and the deformation of the optical element 101.

In FIG. 7A, when a voltage having a voltage value V0 is applied to the optical element 101 at time t0, deformation of the interface 124 of the optical element 101 starts at a time constant t11 (see FIG. 17B). . Even if the voltage application is continued as it is, a considerably long time is required until the interface 124 reaches the desired change amount δ0. Therefore, when the interface 124 is deformed to a deformation amount allowable as an error as an error, for example, 95% (denoted as 0.95δ0) of a desired interface change amount δ0 in FIG. Is considered to have been reached.

If this deformation amount is not reached, the optical element 10
The setting does not proceed to the control following the first one, for example, the control of changing the voltage value applied to the optical element 101. Note that this allowable deformation amount is determined by the optical element 101.
Is determined based on the optical system to be incorporated.

FIG. 18 includes the power supply circuit 126.
2 shows a configuration of a power supply control circuit. Here, the operation when the same voltage is applied to the plurality of connection portions of the transparent electrode 103 will be described.

Reference numeral 130 denotes a central processing unit (hereinafter abbreviated as CPU) for controlling the operation of the optical element 101.
It is a one-chip microcomputer having M, RAM, EEPROM, A / D conversion function, D / A conversion function, and PWM (Pulse Width Modulation) function.

In the power supply circuit 131, 132 is a DC power supply such as a dry battery, 133 is a DC / DC converter that boosts a voltage output from the power supply 132 to a desired voltage value in accordance with a control signal of the CPU 130, and 134 and 135. Is CPU1
30 according to a frequency / duty ratio variable signal that realizes the PWM function, the signal level is changed to D.
This is an amplifier that amplifies to a voltage level boosted by the C / DC converter 133.

The amplifier 134 is connected to the transparent electrode 103 of the optical element 101, and the amplifier 135 is connected to the rod-shaped electrode 125 of the optical element 101. Here, in order to simplify the explanation, the transparent electrode 103 is provided with the amplifier 1.
It is assumed that the voltage output from 34 is applied as a constant value to its surface.

With this configuration, the output voltage of the power supply 132 is applied to the optical element 101 at a desired voltage value, frequency, and duty by the DC / DC converter 133, the amplifier 134, and the amplifier 135 in accordance with the control signal of the CPU 130. become.

FIG. 19 shows voltage waveforms output from the amplifiers 134 and 135. It should be noted that the DC / DC converter 133 sends 10 minutes to the amplifiers 134 and 135 respectively.
The following description is based on the assumption that a voltage of 0 V is output.

As shown in FIG.
4, 135 are connected to the optical element 101, respectively. From the amplifier 134, as shown in FIG.
A voltage having a rectangular waveform is output at a desired frequency and a duty ratio according to a control signal of the CPU 130.

On the other hand, from the amplifier 135, FIG.
As shown in (1), a rectangular waveform voltage having the same frequency and the same duty ratio is output in a phase opposite to that of the amplifier 134 by the control signal of the CPU 130. Thereby, the optical element 1
The voltage applied between the transparent electrode 103 and the rod-shaped electrode 125 is a voltage having a rectangular waveform of ± 100 V, that is, an AC voltage, as shown in FIG.

Therefore, an AC voltage is applied to the optical element 101 by the power supply circuit 131.

Since the effective value of the voltage applied to the optical element 101 from the start of application can be expressed as shown in FIG. 19 (e), the waveform of the AC voltage applied to the optical element 101 will be described below. It will be expressed in accordance with (e).

In the above description, the amplifiers 134, 135
Has been described as outputting a voltage having a rectangular waveform, but the same configuration is obtained with a sine wave output.

In the above description, the case where the power supply 132 is incorporated in the power supply circuit 131 has been described. However, an alternating current may be applied to the optical element 101 by an external power supply.

Next, another conventional optical element will be described with reference to FIG. In the figure, reference numeral 301 denotes the entire optical element. Reference numeral 302 denotes a first sealing plate made of a transparent acrylic or glass disk.

Reference numeral 303 denotes an electrode ring whose outer diameter is uniform.
The inner diameter gradually increases in diameter in the downward direction. The electrode ring 303 is a ring-shaped member in which a resistor such as a mixture of carbon and resin is provided on the surface of a ring member made of a nonconductor.

An insulating layer 304 made of acrylic resin or the like is formed in close contact with the entire inner surface of the electrode ring 303. Since the inner diameter of the insulating layer 304 is uniform, the thickness gradually increases downward. A water-repellent agent is applied to the lower side of the entire inner surface of the insulating layer 304 to form a water-repellent film 311, and a hydrophilic agent is applied to the upper side of the entire inner surface of the insulating layer 304, A hydrophilic film 312 is formed.

Reference numeral 306 denotes a disk-shaped second sealing plate made of transparent acryl or glass, a part of which is provided with a hole, into which a rod-shaped electrode 325 is inserted. Rod electrode 32
The gap between 5 and the hole is sealed with an adhesive.

Reference numeral 307 denotes an aperture plate for limiting the diameter of a light beam incident on the optical element 301, which is fixed on the upper surface of the second sealing plate 306. The lower case 330, the first sealing plate 302, the electrode ring 303, and the second sealing plate 306 are bonded and fixed to each other, and have a sealed space of a predetermined volume surrounded by these members, that is, a liquid chamber. A container as a housing is formed.

This container has an axisymmetric shape with respect to the optical axis 323 except for the insertion portion of the rod-shaped electrode 325. The liquid chamber is filled with the following two types of liquids.

First, the second liquid 32 is placed on the bottom side of the liquid chamber.
2 is dropped in such an amount that the height of the liquid column becomes the same as the height of the water-repellent film 311 forming part. The second liquid 322 is a colorless and transparent silicone oil having a specific gravity of 1.06 and a refractive index of 1.49 at room temperature. Subsequently, the remaining space in the liquid chamber is filled with the first liquid 321. First liquid 3
21 is a mixture of water and ethyl alcohol at a predetermined ratio,
Further, an electrolyte solution having a specific gravity of 1.06 and a refractive index of 1.38 at room temperature to which a predetermined amount of salt has been added.

That is, the first and second liquids 321,
As 322, liquids having the same specific gravity, different refractive indices, and immiscible (insoluble) are selected. The two liquids 321 and 322 form an interface 324 and exist independently without being mixed.

The shape of the interface 324 is determined by the inner wall of the liquid chamber (container), the first liquid 321 and the second liquid 3.
It is determined by the balance of the three interfacial tensions acting on the point where the 22 substances intersect, that is, the outer edge of the interface 324.

Reference numeral 131 denotes a power supply circuit having the same configuration and operation as the power supply circuit 126 shown in FIG.

The amplifier 134 of the power supply circuit 131 is connected to the electrode ring 303, and the amplifier 135 is connected to the rod-shaped electrode 32.
5 is connected.

In the above configuration, a voltage is applied to the first liquid 321 via the rod-shaped electrode 325, and the interface 324 is deformed by the electrowetting effect.

Next, the interface 324 in the optical element 301
With reference to FIG. 21, a description will be given of the deformation and the optical action brought about by the deformation.

First, when no voltage is applied to the first liquid 321, as shown in FIG.
Are the interfacial tension between the two liquids 321 and 322, the interfacial tension between the first liquid 321 and the water repellent film 311 or the hydrophilic film 312 on the insulating layer 304, and the second liquid 322 and the insulating layer 312.
It is determined by the interfacial tension with the water-repellent film 311 or the hydrophilic film 312 on the substrate 04 and the volume of the second liquid 322. The thickness of the first liquid 321 on the optical axis is h1.

On the other hand, when a voltage is applied to the first liquid 321, the interfacial tension between the first liquid 321 and the hydrophilic film 312 decreases due to the electrowetting effect, and the first liquid 321 becomes in contact with the hydrophilic film 312. It crosses over the boundary of the water-repellent film 311 and enters the water-repellent film 311. As a result, FIG.
As shown in (b), the height of the second liquid 322 increases from h1 to h2. The thickness of the first liquid 321 on the optical axis is t2.

As described above, by applying a voltage between the first liquid 321 and the electrode ring 303, the balance of the interfacial tension between the two liquids changes, and the shape of the interface 324 between the two liquids 321 and 322 changes. Thus, an optical element that can freely change the shape of the interface 324 by controlling the voltage of the power supply circuit 131 can be realized.

The first and second liquids 321, 32
Since the lenses 2 have different refractive indices, power as an optical lens is given, and the optical element 301 becomes a variable focus lens whose focal length changes due to a change in the shape of the interface 324.

Further, as compared with the state of FIG.
Since the radius of curvature is shorter at the interface 324 in the state shown in FIG. 21B, the optical element 301 shown in FIG.
The focal length of the optical element 301 is shorter than in the state of FIG.

The principle of deformation of the two-liquid interface due to the electrowetting effect is also described in International Patent No. 99/1845.
No. 6, the interface 324 corresponds to positions A and B of the two liquid interface described in FIG. 6 of the patent.

When an optical element containing a liquid in a closed container as described above does not have a temperature compensation function, the temperature in the container may change due to a change in the surrounding temperature environment or a rise in temperature due to long-term operation. When the liquid undergoes thermal expansion or thermal contraction, the optical power of the lens changes, and the focal length changes.

In order to solve this problem, various proposals have been made. For example, Japanese Patent Laid-Open No. 2000-815
In Japanese Patent Publication No. 03, an optical element provided with a temperature compensating means described below is proposed.

That is, a temperature compensator provided with a tank communicating with the internal space filled with the transparent liquid in the container is provided on the outer peripheral portion of the lens container, and the temperature compensator increases or decreases due to thermal expansion and thermal contraction. The amount of change in the volume of the transparent liquid is absorbed. Further, at least a part of the wall surface of the tank of the temperature compensation unit is an easily deformable elastic wall.

Accordingly, even if the transparent liquid in the container undergoes thermal expansion or thermal contraction due to a change in the surrounding temperature environment or a rise in temperature due to long-term operation, the temperature compensating unit controls the temperature of the volume of the transparent liquid. Fluctuations are absorbed or supplied to suppress fluctuations in optical power due to temperature changes and the like.

[0067]

However, in the configuration proposed in Japanese Patent Application Laid-Open No. 2000-81503, since the temperature compensating portion is provided on the outer peripheral portion of the lens container, the size of the optical element as a whole in the radial direction is increased. There is a problem of inviting.

Accordingly, it is an object of the present invention to provide an optical element utilizing a liquid with a function of absorbing a volume change of the liquid caused by a temperature change without increasing the size of the optical element.

[0069]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an optical element configured to contain a liquid in a liquid chamber formed in a container. And a space defined by the film-like flexible member with respect to the liquid chamber.

Thus, when the liquid expands due to a change in temperature, the volume of the liquid chamber is increased by the deformation of the flexible member so as to enter the space with the expansion, and the liquid shrinks. In this case, the volume of the liquid chamber can be reduced by deforming the flexible member toward the liquid chamber with the decrease. As described above, according to the present invention, the optical element has a function of absorbing the volume change of the liquid accompanying the temperature change with a very simple configuration.
Moreover, since the space is formed within the thickness of the wall of the container, it is possible to prevent the optical element from being enlarged.

If there is a combination of a plurality of members constituting the container near the space, the flexible member is held at the combination of the plurality of members. (Furthermore, the liquid-tightness of a combination part is ensured) and the optical element may be easily assembled.

Further, a first liquid having conductivity or polarity and a second liquid which is not mixed with the first liquid are provided in the liquid chamber.
Liquid is accommodated, and the shape of the interface between the first liquid and the second liquid changes according to the change in the voltage applied between the first liquid and the electrode provided on the container side, so that the optical characteristics are changed. In the optical element having a change, the above-mentioned space and one of the first and second liquids in the liquid chamber may be partitioned by the above-mentioned flexible member.

If an optical element and a photographing apparatus are configured using the above-described optical elements, a compact optical element and a photographing apparatus can be realized.

[0074]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows a configuration of an optical device including an optical element and a power supply control circuit according to a first embodiment of the present invention. In the present embodiment, components common to the optical element and the power supply control circuit described with reference to FIGS. 15 and 16 are denoted by the same reference numerals as in FIGS. 15 and 16 and will not be described. 1 is shown in FIG. 2 to FIG.

In the present embodiment, a container is constituted by the insulating layer 104, the container body 105 and the upper cover 106, and a first liquid 121 and a second liquid 122 are contained in a liquid chamber formed in the container. Interface 124 without mixing with each other
Are formed and housed.

A space 152 is formed in at least one portion of the entire circumference of the upper part of the container body (wall portion) 105 so as to fit within the originally required wall thickness of the container body 105. This space 152 has an outer wall portion 105b at an upper portion of the container body 105 and an inner wall portion 10 which is one step lower than the outer wall portion 105b.
5a, and without a sealing film 150, 151 described later, through the gap between the upper end surface of the inner wall portion 105a and the lower surface of the upper cover 106, to the liquid chamber side. It is open.

The container body 105 and the upper cover 106
Two sealing films (film-like flexible members) 150 and 151 formed in a ring shape are overlapped with (a plurality of members constituting the container).

In this embodiment, two sealing films are used, but one sealing film is
5 and the upper cover 106. However, the use of two sealing films as in the present embodiment is more excellent in assemblability.

The sealing films 150 and 151 are formed of, for example, a single-layer polymer film or a multi-layer polymer film, are impermeable to liquid and air, and are easily elastically deformed.

The portion of the sealing film 150 not facing the space 152 is fixed to the upper end surface of the container body 105 by bonding or the like. The portion of the sealing film 150 facing the space 152 has an outer diameter side portion on the upper end surface of the outer wall portion 105b of the container body 105 and an inner diameter side portion on the upper end surface of the inner wall portion 105a of the container body 105. Each is fixed by bonding or the like. Thus, the sealing film 150 can seal and partition the liquid chamber and the space 152 from each other.

Therefore, the first liquid 121 does not leak from the liquid chamber into the space 152, and air does not leak from the space 152 into the liquid chamber.

The sealing film 151 is provided on the upper cover 1.
06 is fixed to the outer diameter side portion by bonding or the like.

Further, both sealing films 150 and 151 are integrated by heat welding or the like. However, the sealing film 1
The outer edge 150a of the portion sealing the space 152 in 50 is integrated with the outer edge 151a of the sealing film 151 by heat welding or the like. Thus, the combination of the container body 105 and the upper cover 106 can be sealed in a liquid-tight manner.

Next, the temperature compensation function of the sealing film 150 and the space 152 will be described with reference to FIGS.

As shown in FIG. 2, at room temperature, the container body 1
The sealing film 150 fixed to 05 slightly enters the space 152 by the liquid pressure in the liquid chamber.

As shown in FIG. 3, when the ambient temperature of the optical element 201 rises and the first liquid 121 thermally expands, the sealing film 150 is placed inside the space 152 by the volume increase. By further bending, the substantial volume in the liquid chamber increases, and the increased volume is absorbed.

On the other hand, as shown in FIG.
When the temperature of the surrounding environment of the first liquid 121 is reduced by heat and the first liquid 121 is thermally contracted, the sealing film 150 is reduced by the reduced volume.
Is bent from the space 152 side to the liquid chamber side, the volume of the liquid chamber is substantially reduced, and the reduced volume is absorbed.

Therefore, the thermal expansion of the first liquid 121
A change in the shape of the interface 124 with the second liquid 122 due to heat shrinkage can be prevented, and a change in optical power can also be prevented.

As described above, according to the present embodiment, the optical element 201 (particularly, the outer diameter of the container) can be formed with a simple configuration without increasing the size of the first liquid 121 due to a temperature change. Fluctuation of the optical power can be prevented.

In this embodiment, the optical element utilizing the electrowetting effect has been described.
The temperature compensation structure described in the present embodiment has at least one
The present invention can be applied to an optical element that is configured by storing a type of liquid in a container.

(Second Embodiment) FIG. 5 shows a second embodiment of the present invention.
1 illustrates a configuration of an optical device including an optical element and a power supply control circuit according to an embodiment. Note that, in the present embodiment, components common to the first embodiment are denoted by the same reference numerals as in the first embodiment, and description thereof is omitted. FIG. 6 to FIG. 8 show a portion B in FIG.

In the optical element 250 of this embodiment, a container is constituted by the insulating layer 104, the container body 105, the ring-shaped upper container 160, and the upper cover 106 fixed to the inner diameter side of the upper container 160 by bonding or the like. In the liquid chamber formed in this container, the first liquid 121 and the second liquid 122 are accommodated so as to form an interface 124 without being mixed with each other.

Container body 1 in upper container (wall) 160
A concave portion 160a that forms a space 152 'together with the outer peripheral end surface of the upper cover 106 is formed in at least one of the entire periphery of the inner diameter side portion opposing the upper end surface of the upper cover 105.
The space 152 ′ is of a size that fits within the originally required wall thickness of the upper container 160, and a sealing film 170 described later.
In the state where there is no 1,171, it opens to the liquid chamber side through a gap formed between the upper end surface of the container body 105 and the lower surface of the upper cover 106.

Further, the upper end surface of the container body 105 and the upper container 1
Two ring-shaped sealing films (flexible members on the film) 17 are provided between the lower cover 60 and the lower surface of the upper cover 106.
0,171 are arranged. These sealing films 17
0,171 are the sealing films 15 of the first embodiment.
0, 151 are formed of the same material.

The sealing film 170 is fixed to the upper end surface of the container body 105 on the back side 170a of the sealing film 170 by bonding or the like.

On the other hand, the space 15 in the sealing film 171
The entire surface of the portion not facing 2 'is the upper container 160.
And the lower surface of the upper cover 106 are fixed by bonding or the like. The space 15 in the sealing film 171
An inner peripheral portion 171a of the portion facing 2 'is fixed to an outer peripheral portion 106a on the lower surface of the upper cover 106 by bonding or the like.

Further, both sealing films 170 and 171 are integrated by heat welding or the like. However, the sealing film 1
The outer edge 171b of a portion of the 71 facing the space 152 'is integrated with the outer edge 171b of the sealing film 170 by heat welding or the like. This allows
The sealing films 170 and 171 can partition the liquid chamber with respect to the space 152 ′ and can seal the liquid chamber in a liquid-tight state at the place where the container body 105 and the upper container 160 are combined.

Note that the concave portion 1 on the lower surface of the upper container 160
A groove 153 extending in an outer peripheral direction from the concave portion 160a is formed in a portion where the 60a is formed, and the upper container 160 and the sealing film 171 are not fixed in this portion. Therefore, the sealing film 171 can be elastically deformed freely with respect to the concave portion 160a (that is, the space 152 ') formed in the upper container 160.

Next, the temperature compensation function of the sealing film 171 and the space 152 'will be described with reference to FIGS.

As shown in FIG. 6, at room temperature, the upper cover 1
Sealing film 17 having an inner diameter portion 171a fixed to 06
1 slightly enters the space 152 'due to the liquid pressure in the liquid chamber.

As shown in FIG. 7, when the temperature of the surrounding environment of the optical element 250 rises and the first liquid 121 thermally expands, the sealing film 171 moves inside the space 152 'by the volume increase. By further bending, the volume in the liquid chamber is substantially increased, and the increased volume is absorbed.

On the other hand, as shown in FIG.
When the temperature of the surrounding environment of the first liquid 121 is reduced by heat and the first liquid 121 is thermally contracted, the sealing film 171 is reduced by the reduced volume.
Is bent from the space 152 'to the liquid chamber side, the substantial volume in the liquid chamber is reduced, and the reduced volume is absorbed.

Therefore, the thermal expansion of the first liquid 121
A change in the shape of the interface 124 with the second liquid 122 due to heat shrinkage can be prevented, and a change in optical power can also be prevented.

As described above, according to the present embodiment, a change in optical power due to a change in the volume of the first liquid 121 due to a change in temperature can be prevented with a simple configuration and without increasing the size of the optical element 250. can do.

In the present embodiment, the optical element utilizing the electrowetting effect has been described.
The temperature compensation structure described in the present embodiment has at least one
The present invention can be applied to an optical element that is configured by storing a type of liquid in a container.

(Third Embodiment) FIG. 9 shows a third embodiment of the present invention.
1 illustrates a configuration of an optical device including an optical element and a power supply control circuit according to an embodiment. In the present embodiment, components common to the optical element and the power supply control circuit described with reference to FIGS. 20 and 21 will be denoted by the same reference numerals as in FIGS. 20 and 21 and will not be described. FIG.
The part C in the middle is shown in FIGS.

Reference numeral 330 denotes a lower case (wall) formed in a ring shape.
Hold 2. The lower case 330 is formed of a non-conductor, and is adhered and fixed to the electrode ring 303 in a liquid-tight state.

In the optical element 350 of the present embodiment, a container is constituted by the lower case 330, the first sealing plate 302, the electrode ring 303, and the second sealing plate 306. First liquid 321 and second liquid 32
2 are accommodated without forming an interface 324.

On the inner diameter side of the lower case 330, a holding portion 330a for holding the first sealing plate 302 is formed.
Further, at least one place on the entire circumference, the holding portion 330
A concave portion 330b is formed adjacent to a.

The outer diameter side portion of the first sealing plate 302 extends from the upper side of the holding portion 330a to halfway above the concave portion 330b, and the outer diameter side portion of the first sealing plate 302 and the concave portion 330b An adhesive 332 is filled in between this and the (bottom), and this portion is sealed.

The space 331 excluding the adhesive 332 among the spaces in the concave portion 330b is open to the liquid chamber in the absence of a sealing film 333 described later. The space 331 fits within the originally required thickness of the lower case 330.

Reference numeral 333 denotes a ring-shaped sealing film, which is formed of the same material as in the first and second embodiments.

The entire surface of the portion of the sealing film 333 not facing the space 331 is fixed to the upper surface of the lower case 330 and the upper surface of the outer edge 302a of the first sealing plate by bonding or the like.

The space 33 in the sealing film 333 is
In the portion facing 1, the inner diameter side portion 333 a is bonded to the upper surface of the outer edge portion 302 a of the first sealing plate 302, and the outer diameter side portion 333 b is bonded to the upper surface of the outer diameter side portion 330 c of the lower case 330. It is fixed at. That is, the sealing film 333 seals and partitions the liquid chamber and the space 331 from each other.

Therefore, the second liquid 322 does not leak from the liquid chamber into the space 331, and air does not leak from the space 331 into the liquid chamber.

Next, the temperature compensation function of the sealing film 333 and the space 331 will be described with reference to FIGS.

As shown in FIG. 10, the sealing film 333 hardly enters the space 331 at normal temperature.

As shown in FIG. 11, when the ambient temperature of the optical element 350 rises and the first liquid 321 thermally expands, the sealing film 333 is placed inside the space 331 by the volume increase. The bending increases the substantial volume in the liquid chamber, and the increased volume is absorbed.

On the other hand, as shown in FIG.
When the first liquid 321 thermally shrinks due to a decrease in the ambient temperature of zero, the sealing film 33 is reduced by the volume reduction.
When 3 is bent toward the liquid chamber, the substantial volume in the liquid chamber is reduced, and the reduced volume is absorbed.

Therefore, the thermal expansion of the first liquid 321
A change in the shape of the interface 324 with the second liquid 322 due to heat shrinkage can be prevented, and a change in optical power can also be prevented.

As described above, according to the present embodiment, a change in optical power due to a change in the volume of the first liquid 121 due to a change in temperature can be prevented with a simple configuration and without increasing the size of the optical element 350. can do.

Note that, apart from the one shown in FIG. 9, the electrode ring 303 and the lower case 330 are integrated with a non-conductor, a resistor is provided on the surface of the portion corresponding to the electrode, and the resistor is further placed on the resistor. In an optical element having the insulating layer 304 formed thereon, a temperature compensation structure can be similarly formed.

In the present embodiment, the optical element utilizing the electrowetting effect has been described.
The temperature compensation structure described in the present embodiment has at least one
The present invention can be applied to an optical element that is configured by storing a type of liquid in a container.

(Fourth Embodiment) FIG. 13 shows an example in which the optical element 230 of the first embodiment is applied to a photographing device as an optical device. Photographing device 550 of the present embodiment
Is a so-called digital still camera in which a still image is photoelectrically converted by an image sensor into an electric signal and this is recorded as digital data.

In FIG. 13, reference numeral 540 denotes a photographing optical system (imaging optical system) composed of a plurality of lens groups, and includes a first lens group 541, a second lens group 542, and an optical element 230.

This photographing optical system 540 includes the first lens group 5
The focus is adjusted by moving the optical element 41 in the optical axis direction, and the optical element 2
Zooming is performed by 30 power changes. The second lens group 542 is a relay lens group that does not move.

The optical element 230 is disposed between the first lens group 541 and the second lens group 542, and the distance between the first lens group 541 and the optical element 230 is changed by changing the diameter of the aperture. Aperture unit 54 for adjusting the amount of light
3 are arranged.

An image sensor 544 is disposed at the focal position (planned image plane) of the photographing optical system 540. this is,
A photoelectric conversion element, such as a two-dimensional CCD, including a plurality of photoelectric conversion units for converting the irradiated light energy into charges, a charge storage unit for storing the charges, and a charge transfer unit for transferring the charges and sending them to the outside is used. .

An image signal processing circuit 545 performs A / D conversion of an analog image signal input from the image sensor 544, and performs image processing such as AGC control, white balance, γ correction, and edge enhancement.

Reference numeral 551 denotes a display such as a liquid crystal display.
The image of the subject acquired through the image sensor 544 and the operation status of the photographing device 550 are displayed.

A main switch 552 activates the CPU 530 from the sleep state to the program execution state.

Reference numerals 553a and 553b denote zoom switches on the wide (W) side and the tele (T) side, respectively.
In response to the operation of these zoom switches by the photographer, driving for changing the focal length of the photographing optical system 540 is performed.

Reference numeral 554 denotes an operation switch group other than the above switches, which includes a photographing preparation switch, a photographing start switch, a photographing condition setting switch for setting shutter time, and the like.

Reference numeral 555 denotes a focus detection device which performs a focus detection operation of a phase difference detection type used in a single-lens reflex camera, or detects a distance to a subject by using the principle of triangulation.

Reference numeral 556 denotes a focus drive circuit,
An actuator for moving the lens group 541 in the optical axis direction and a driver circuit are included, and a focus operation is performed based on a focus signal calculated by the focus detection device 555.
The photographing optical system 540 is focused.

Reference numeral 557 denotes an external memory for recording a photographed image signal. Specifically, a removable PC card type flash memory or the like is preferable.

FIG. 14 is a diagram showing the C
9 is a control flowchart illustrating an operation of a PU 530. Hereinafter, the operation of the imaging device 550 will be described with reference to FIGS.

In step S101, it is determined whether or not the main switch 552 has been turned on. If the main switch 552 has not been turned on, the apparatus enters a standby mode for waiting for the operation of various switches. If it is determined in step S101 that the main switch 552 has been turned on, the standby mode is released, and the process proceeds to the next step S102 and subsequent steps.

In step S102, the photographer sets the photographing conditions. For example, settings such as an exposure control mode setting (shutter priority AE, program AE, etc.), an image quality mode (large or small number of recording pixels, a large or small image compression ratio, etc.), a strobe mode (forcible light emission, light emission inhibition, etc.) are accepted.

In step S103, W is determined by the photographer.
It is determined whether or not the side zoom switch 553a has been operated. If the on operation has not been performed, the process proceeds to step S104. If the W-side zoom switch 553a has been operated here, the flow shifts to step S121.

In step S121, the operation amount (operation direction, ON time, etc.) of the W-side zoom switch 553a is detected, and the corresponding focal length change amount is calculated based on the operation amount (S122). Then, in step S123,
The amount of voltage applied to the optical element 230 is determined based on the calculation result, and the output voltage of the power supply circuit 131 is controlled to apply the voltage to the optical element 230 (S124). Then, the process returns to step S102.

That is, when the W-side zoom switch 553a is continuously operated, Steps S102 to S124 are repeatedly executed, and the W-side zoom switch 553a is repeatedly operated.
When the ON operation of 3a is completed, the process proceeds to step S104.

In step S104, T
It is determined whether or not the side zoom switch 553b has been operated. If the ON operation has not been performed, the process proceeds to step S105. If the T-side zoom switch 553b has been operated here, the flow shifts to step S121.

In step S121, the operation amount (operation direction, ON time, etc.) of the T-side zoom switch 553b is detected, and the corresponding focal length change amount is calculated based on the operation amount (S122). Then, in step S123,
The amount of voltage applied to the optical element 230 is determined based on the calculation result, and the voltage is applied to the optical element 230 by controlling the output voltage of the power supply circuit 231 (S124). Then, the process returns to step S102.

That is, when the T-side zoom switch 553b is continuously operated, steps S102 to S124 are repeatedly executed, and the T-side zoom switch 15
When the on operation of Step 3b is completed, the process proceeds to Step S105.

In the step S105, the photographing preparation switch (FIG. 14) of the operation switches 554 is selected by the photographer.
It is determined whether or not the on operation of SW1 is performed in the flowchart of (1). If the ON operation has not been performed, the process returns to step S102, and the reception of the shooting condition setting and the determination of the operation of the zoom switch 553 are repeated. Step S
If it is determined in step 105 that the shooting preparation switch has been turned on, the process proceeds to step S111.

In step S111, the image pickup device 544 and the signal processing circuit 545 are driven to obtain a preview image. The preview image is an image acquired before photographing in order to appropriately set the photographing conditions of the final recording image and to allow the photographer to grasp the photographing composition.

In step S112, step S111
Recognize the light receiving level of the preview image acquired in step (1). Specifically, in the image signal output from the image sensor 544, the highest, lowest, and average output signal levels are calculated,
The amount of light incident on the image sensor 544 is recognized.

In step S113, step S112
The aperture unit 543 provided in the photographing optical system 540 is driven based on the amount of received light recognized in the step (a) to adjust the aperture diameter of the aperture unit 543 so as to obtain an appropriate amount of light.

In step S114, step S111
Is displayed on the display 551.
Subsequently, in step S115, the focus adjustment state of the imaging optical system 540 is detected using the focus detection device 555. Subsequently, in step S116, the focus driving circuit 55
6, the first lens group 141 is moved back and forth in the optical axis direction,
Perform focusing operation.

Thereafter, the flow advances to step S117 to determine whether or not the photographing switch (in the flowchart, denoted as SW2) has been turned on. When the ON operation has not been performed, the process returns to step S111, and steps from acquisition of the preview image to focus driving are repeatedly executed.

As described above, when the photographer turns on the photographing switch while the photographing preparation operation is being repeatedly executed, the process jumps from step S117 to step S131.

In step S131, imaging is performed. That is, the subject image formed on the image sensor 544 is photoelectrically converted, and charges proportional to the intensity of the optical image are stored in the charge storage units near each light receiving unit.

In step S132, step S131
Read out the charge accumulated at
The read analog signal is input to the signal processing circuit 145.

In the step S133, the signal processing circuit 54
In step 5, the input analog image signal is A / D converted, subjected to image processing such as AGC control, white balance, γ correction, edge enhancement, and the like.
JPEG compression or the like is performed by the image compression program stored in the “0”.

At step S134, at step S1
At the same time as recording the image signal obtained in step S33 in the memory 557, the preview image is deleted once in step S135, and the image signal obtained in step S133 is displayed again on the display 551. Thereafter, the power supply circuit 231 is controlled to turn off the voltage application to the optical element 230 (S13).
6), a series of photographing operations ends.

In the present embodiment, the case where the optical element of the first embodiment is used has been described, but the optical element described in the second embodiment can also be used.

In this embodiment, a digital still camera is taken as an example of a photographing device. However, the optical element of the present invention is not limited to a video camera, a silver halide camera, or other optical devices having an optical system. The present invention can be applied to a device without impairing the effect.

[0159]

As described above, according to the present invention,
The optical element can be provided with a function of absorbing a volume change of the liquid due to a temperature change with a very simple configuration and while avoiding an increase in the size of the optical element.

In the case where there is a combination of a plurality of members constituting the container near the space, if the flexible member is held at the combination of the plurality of members, the flexible member Holding in a container (and
It is possible to easily assemble the optical element) and to assemble the optical element.

If an optical element and a photographing device are constituted by using the above-described optical element, a compact optical element and a photographing device can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical element and a power supply control circuit according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is a diagram illustrating a volume change absorbing operation of the optical element according to the first embodiment at the time of thermal expansion of a liquid.

FIG. 4 is a diagram illustrating a volume change absorbing operation of the optical element according to the first embodiment when a liquid contracts.

FIG. 5 is a configuration diagram of an optical element and a power supply control circuit according to a second embodiment of the present invention.

FIG. 6 is an enlarged view of a portion B in FIG.

FIG. 7 is a diagram illustrating a volume change absorbing operation during thermal expansion of a liquid in the optical element of the second embodiment.

FIG. 8 is a diagram illustrating a volume change absorbing operation of the optical element according to the second embodiment when a liquid contracts.

FIG. 9 is a configuration diagram of an optical element and a power supply control circuit according to a third embodiment of the present invention.

FIG. 10 is an enlarged view of a portion C in FIG. 9;

FIG. 11 is a diagram illustrating a volume change absorbing operation during thermal expansion of a liquid in the optical element according to the third embodiment.

FIG. 12 is a diagram illustrating a volume change absorbing operation of the optical element according to the third embodiment when a liquid contracts.

FIG. 13 is a configuration diagram of an imaging device (optical device) according to a fourth embodiment of the present invention.

FIG. 14 is a flowchart showing the operation of the photographing apparatus.

FIG. 15 is a sectional view of a conventional optical element.

FIG. 16 is an explanatory diagram of an operation when a voltage is applied to a conventional optical element.

FIG. 17 is a relationship diagram between applied voltage and interface deformation of a conventional optical element.

FIG. 18 is an explanatory diagram of a conventional optical element and a power supply control circuit.

FIG. 19 is a diagram illustrating the operation of a conventional power supply control circuit.

FIG. 20 is an explanatory diagram of another conventional optical element and a power supply control circuit.

FIG. 21 is a diagram illustrating an operation when a voltage is applied to another conventional optical element.

[Explanation of symbols]

101, 201, 250, 301, 350 Optical element 102 Transparent substrate 103 Transparent electrode 104, 304 Insulating layer 105 Container main body 150, 151, 170, 171, 333 Sealing film 106 Upper cover 160 Upper container 121, 321 First liquid 122,322 Second liquid 123,323 Optical axis 124,324 Interface 125,325 Rod electrode 152,152 ', 331 Space 302 First sealing plate 303 Electrode ring 330 Lower case

Claims (6)

[Claims] 1. An optical element configured to contain a liquid in a liquid chamber formed in a container, wherein the liquid chamber is partitioned by a film-shaped flexible member within a thickness of a wall portion of the container. An optical element characterized by forming a defined space. 2. The optical element according to claim 1, wherein the flexible member elastically deforms into the space side and the liquid chamber side as the volume of the liquid changes. 3. A combination portion of a plurality of members constituting the container near the space, wherein the flexible member is held at a combination portion of the plurality of members. 3. The optical element according to 1 or 2. 4. A first liquid having conductivity or polarity and a second liquid which is not mixed with the first liquid is provided in the liquid chamber.
And the shape of the interface between the first liquid and the second liquid changes according to the change in the voltage applied between the first liquid and the electrode provided on the container side. An optical element whose optical characteristics are changed by the flexible member, wherein the space and one of the first and second liquid storage regions in the liquid chamber are partitioned by the flexible member. The optical element according to claim 1, wherein: 5. An optical device, comprising: the optical element according to claim 1; and a power supply control circuit that changes a voltage applied between the first liquid and the electrode. 6. An imaging optical system including the optical element according to claim 1, and a power supply control circuit for changing a voltage applied between the first liquid and the electrode. Photographing device.