JP2001249261A - Optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical device capable of controlling the drive of an optical element using electrocapillarity by a simple driving circuit when controlling the drive of the optical element, accurately controlling the optical power in a short time and capable of driving with a small power. SOLUTION: The optical device with the optical element whose optical property is changed in accordance with a change in a surface shape when a voltage is applied is provided with a power feeding means for applying a prescribed AC voltage on an electrode arranged in the container so as to change the surface shape, and an apply voltage control means for controlling the apply voltage, and the duty factor of the AC voltage is controlled by the apply voltage control means, and the surface shape is changed by controlling the duty factor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical device including an optical element utilizing electrowetting (electrocapillary phenomenon), and more particularly to a power supply means for driving the element.

[0002]

2. Description of the Related Art Among optical systems incorporated in optical devices such as still cameras and video cameras, most of which can change the focal length include a part of a lens (or a lens group) constituting the optical system. The focal length of the entire optical system is changed by mechanically moving the optical system in the optical axis direction. For example, in Japanese Patent No. 2633079, a first-group lens that moves in the optical axis direction by zooming, a first-group barrel that moves in the optical axis direction when the first-group lens moves, and a movement of the first-group barrel A zoom lens barrel having a cam barrel that moves in the optical axis direction, wherein the first group barrel fits on the outer diameter side of the fixed barrel, and the cam barrel fits on the inner diameter side of the fixed barrel. Wherein the front part of the cam barrel is fitted into the inner diameter side of the first lens barrel, and the first lens is moved by moving the cam cylinder in the optical axis direction. Is moved to perform a zooming operation. As described above, when the focal length is changed by mechanically moving the lens (or the lens group) in the optical axis direction, there is a problem that the mechanical structure of the optical device becomes complicated.

[0003] In order to solve this problem, there is a method in which the focal length is made variable by changing the optical characteristics of the lens itself. For example, in Japanese Patent Application Laid-Open No. H08-114703, a working fluid is sealed in a pressure chamber having at least one surface side formed of a transparent elastic film, and the transparent elastic film is deformed by the pressure of the working liquid acting on the transparent elastic film.
When the focal length is variably controlled, the deformed shape of the transparent elastic film is optimized so that the occurrence of lens aberration is reduced, and the pressure of the working fluid in the pressure chamber is reduced by the pressure formed on the transparent elastic film. Provided is a variable focus lens that measures a sensor and adjusts the pressure of the working fluid based on the value to suppress fluctuations in the focal length due to thermal expansion and contraction of the working fluid. .

In Japanese Patent Application Laid-Open No. H11-133210, a potential difference is applied between the first electrode and the conductive elastic plate to generate a suction force due to Coulomb force to reduce the distance between the two. With the volume of the transparent liquid rejected from the distance of, the central portion of the transparent elastic plate can be deformed by protruding convexly rearward of the transparent liquid.
Then, a convex lens is formed by the transparent elastic plate deformed into a convex shape, the transparent plate, and the transparent liquid filling the space between the transparent plate and the transparent plate. By adjusting the potential difference, the power of this convex lens is adjusted to form a varifocal lens. are doing.

On the other hand, a variable focus lens using the electrocapillary phenomenon is disclosed in WO99 / 18456. Using this technique, electrical energy is directly transferred to the first liquid and the second liquid.
Can be used to change the shape of the lens formed by the interface with the liquid, so that the variable focus can be achieved without mechanically moving the lens.

[0006]

However, the above-mentioned prior art has problems in the following points.
For example, in JP-A-8-114703 described above,
There is a description of an actuator control device for driving an actuator using a unimorph mechanism using a piezoelectric element formed on a transparent elastic film as an actuator.
However, this known technique has a disadvantage that the elastic deformation portion has high rigidity, and as a result, a large power is required for driving the actuator.
Similarly, Japanese Unexamined Patent Application Publication No. 11-133210 mentioned above has a drawback that the rigidity of the elastically deformable portion is high, and as a result, a large power is required for driving the actuator. In addition, W
In O99 / 18456, the optical power can be changed with a small amount of power because there is no mechanical moving part. Not disclosed.

Therefore, the present invention solves the above-mentioned problems in the conventional art, and can control the optical element utilizing the electrocapillary phenomenon with a simple driving circuit.
It is an object of the present invention to provide an optical device capable of accurately controlling the optical power in a short time and driving with a small amount of power.

[0008]

SUMMARY OF THE INVENTION The present invention provides an optical device having the following constitutions (1) to (15) to achieve the above object. (1) A conductive or polar first liquid and a second liquid which are not mixed with the first liquid are hermetically sealed in a container with their interfaces having a predetermined shape, An optical device having an optical element whose optical characteristics change due to a change in an interface shape due to application of a voltage to an electrode provided in the container, wherein a predetermined AC voltage is applied to the electrode to change the interface shape. And an applied voltage control means for controlling the AC voltage to be applied, wherein the applied voltage control means controls a duty ratio of the AC voltage, and the interface is controlled by controlling the duty ratio. An optical device characterized by changing its shape. (2) The optical device according to (1), wherein the power supply unit has a configuration in which an AC voltage having a rectangular wave whose peak voltage and frequency are substantially constant is applied. (3) A conductive or polar first liquid and a second liquid that are not mixed with the first liquid are hermetically sealed in a container with their interfaces having a predetermined shape, An optical device having an optical element whose optical characteristics change due to a change in an interface shape due to application of a voltage to an electrode provided in the container, wherein a predetermined AC voltage is applied to the electrode to change the interface shape. Power supply means, and an applied voltage control means for controlling the applied AC voltage, the applied voltage control means having a configuration for controlling the frequency of the AC voltage, and controlling the frequency to form the interface shape. An optical device characterized by changing. (4) The optical element according to the above (3), wherein the power supply means has a configuration for applying an AC voltage that is a rectangular wave having a substantially constant duty ratio and a peak voltage. (5) A conductive or polar first liquid and a second liquid which are not mixed with each other are sealed in a container with their interfaces having a predetermined shape, An optical device having an optical element whose optical characteristics change due to a change in an interface shape caused by application of a voltage to an electrode provided in the container, wherein an additional element is used for observing or recording a light beam passing through the optical element. Means, power supply means for applying a predetermined AC signal to the electrode to change the interface shape, power supply control means for controlling the applied AC signal, and additional control means for controlling the operation of the additional means. Having, according to the control state of the additional control means,
An optical device, wherein the frequency of the AC signal is switched by the power supply control means. (6) The power supply control means sets the AC voltage to the first frequency at the start of voltage application to the optical element, and switches the AC voltage to the second frequency after the deformation of the optical element is completed. The optical device according to (5), wherein: (7) The adding unit has a photographing unit, and the power supply control unit sets the AC voltage to the second frequency when the photographing unit prepares for photographing for recording an image, and the photographing unit records the image. The optical device according to the above (5) or (6), wherein the AC voltage is switched to the first frequency at the time of photographing. (8) The first liquid and the second liquid have substantially different refractive indices, and their interfaces are sealed in the container with a large R-shape when no voltage is applied. The optical device according to any one of the above (1) to (7), wherein (9) The first liquid and the second liquid have substantially the same refractive index, and are sealed in the container in a state where their interfaces have a substantially flat shape when the voltage is not applied. The optical device according to any one of the above (1) to (7). (10) The electrode includes a first electrode and a second electrode insulated from the first liquid, and the first electrode is provided so as to be electrically connected to the first liquid. The optical device according to any one of the above (1) to (9), wherein (11) The optical device according to (10), wherein the first electrode is provided so as to be electrically connected to the first liquid from a side surface of the container. (12) The optical device according to (10), wherein the first electrode is provided so as to be electrically connected to the first liquid from an upper surface side of the container. (13) The optical device according to (10), wherein the second electrode is provided on a side surface of the container. (14) the second electrode is a ring-shaped electrode,
The optical device according to (13), wherein the optical device is arranged so as to surround the second liquid. (15) The optical device according to the above (14), wherein the ring-shaped electrode has a shape whose inner diameter gradually changes in the light beam emission direction.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an embodiment of the present invention,
A power supply unit for applying a predetermined AC voltage to an electrode for changing an interface shape by applying the above-described configuration, an applied voltage control unit for controlling an applied voltage, and a duty cycle of the AC voltage. Configured to control the ratio,
By changing the duty ratio of the applied voltage, the effective value of the applied voltage to the optical element can be controlled, and the optical characteristics of the optical element can be accurately controlled. Further, by configuring the power supply unit to apply an AC voltage that is a rectangular wave whose peak voltage and frequency are substantially constant, a simple digital control circuit controls the effective value of the voltage applied to the optical element,
It is possible to accurately control the optical characteristics of the optical element. A power supply unit for applying a predetermined AC voltage to an electrode for changing an interface shape; an applied voltage control unit for controlling an applied voltage; and the applied voltage control unit configured to control a frequency of the AC voltage. By changing the frequency of the applied voltage, the energy conversion efficiency of interface deformation with respect to the input power to the optical element can be controlled, and the optical characteristics of the optical element can be accurately controlled. Further, by configuring the power supply unit to apply an AC voltage that is a rectangular wave having a substantially constant peak voltage and a duty ratio, a simple digital control circuit can be used to reduce the interface deformation with respect to the input power to the optical element. It is possible to control the energy conversion efficiency and accurately control the optical characteristics of the optical element. A power supply unit for applying a predetermined AC voltage to the electrodes to change the interface shape; and an applied voltage control unit for controlling the applied voltage, wherein the applied voltage control unit controls the frequency of the AC voltage. By providing a configuration for controlling and changing the interface shape by controlling the frequency, the frequency of the voltage applied to the optical element is switched in accordance with the assumption of the deformation control of the interface of the optical element. It becomes possible. Further, the power supply control means is configured to set the AC voltage to the first frequency at the start of voltage application to the optical element, and to switch the AC voltage to the second frequency after the deformation of the optical element is completed. Thus, it is possible to drive the optical element at the first frequency when deforming the interface, and at the second frequency when the deformation of the interface is completed and its shape is maintained. The adding means has a photographing means,
The power supply control means sets the AC voltage to the second frequency when the photographing means prepares for photographing for recording an image, and switches the AC voltage to the first frequency when the photographing means performs photographing for recording an image. By configuring
When the optical device is in the shooting preparation stage, the optical element can be driven at the first frequency, and when shifting from the shooting preparation stage to the shooting operation, the optical device can be driven by switching to the second frequency before the shooting operation. Become.

[0010]

Embodiments of the present invention will be described below. [Embodiment 1] FIGS. 1 to 11 are views for explaining the configuration of Embodiment 1 of the present invention, and FIG. 2 is a sectional view showing the configuration of an optical element of the present embodiment. First, a configuration and a manufacturing method of the optical element of the present embodiment will be described with reference to FIG. In FIG. 2, reference numeral 101 denotes the entire optical element of the present invention;
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 (ITO) 103 made of indium tin oxide is formed by sputtering, and on the upper surface, a transparent acrylic insulating layer 104 is provided in close contact. The insulating layer 104 is formed on the transparent electrode 103.
A replica resin is dropped at the center of the plate, pressed with a glass plate to smooth the surface, and then cured by UV irradiation. A cylindrical container 105 having a light-shielding property is bonded and fixed to the upper surface of the insulating layer 104, and a transparent acrylic cover plate 106 is bonded and fixed to the upper surface thereof. An aperture plate 107 having an opening is arranged. In the above configuration, the insulating layer 104 and the container 10
5, a closed space of a predetermined volume surrounded by the upper cover 106,
That is, a housing having a liquid chamber is formed. The wall surface of the liquid chamber is subjected to the following surface treatment.

First, the diameter D
A water-repellent treatment agent is applied within the range of 1 to form a water-repellent film 111. As the water repellent, a fluorine compound or the like is preferable. Further, a hydrophilic treatment agent is applied to a region outside the diameter D1 on the upper surface of the insulating layer 104 to form a hydrophilic film 112. As the hydrophilic agent, a surfactant, a hydrophilic polymer and the like are preferable. On the other hand, on the lower surface of the cover plate 106, a hydrophilic treatment is performed within the range of the diameter D2, 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. Further, a hole is formed in a part of the container 105, and a rod-like electrode 125 is inserted therein, and sealed with an adhesive to maintain the hermeticity of the liquid chamber. A power supply means 126 is connected to the transparent electrode 103 and the rod-shaped electrode 125, and a predetermined voltage can be applied between both electrodes by operating the switch 127.

The liquid chamber having the above configuration is filled with the following two types of liquids. First, the water-repellent film 11 on the insulating layer 104
A predetermined amount of the second liquid 122 is dropped on the first liquid 122. 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.
On the other hand, 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.
An electrolytic solution having a specific gravity of 1.06 and a refractive index of 1.38 at room temperature. That is, the first and second liquids have the same specific gravity,
Liquids that are insoluble in each other are selected. Therefore, both liquids form an interface 124, and each liquid exists independently without being mixed.

Next, the shape of the interface will be described. First, when no voltage is applied to the first liquid, the interface 1
The shape of 24 is the interfacial tension between the two liquids, the interfacial tension between the first liquid and the water-repellent film 111 or the hydrophilic film 112 on the insulating layer 104, the second liquid and the water-repellent film 111 on the insulating layer 104 or It is determined by the interfacial tension with the hydrophilic film 112 and the volume of the second liquid. In the present embodiment, the material is selected such that the interfacial tension between silicon oil, which is the material of the second liquid 122, and the water-repellent film 111 is relatively small. That is, since the wettability between the two materials is high, the second liquid 122
The outer edge of the lens-shaped liquid droplet formed by 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 A of the lens bottom surface formed by the second liquid
1 is equal to the diameter D1 of the water-repellent film 111. On the other hand, since the specific gravity of both liquids is equal as described above, gravity does not act. The interface 124 becomes a spherical surface, and has a radius of curvature and a height h.
1 is determined by the volume of the second liquid 122. Also, the first
The thickness of the liquid on the optical axis is t1.

On the other hand, when the switch 127 is closed, the first
When a voltage is applied to the liquid 121, the interfacial tension between the first liquid 121 and the hydrophilic film 112 decreases due to the electrocapillary phenomenon, and the first liquid crosses the boundary between the hydrophilic film 112 and the hydrophobic film 122 and becomes hydrophobic. It penetrates into the film 122. As a result, as shown in FIG. 3, the diameter of the bottom surface of the lens formed by the second liquid is A.
It decreases from 1 to A2 and the height increases from h1 to h2.
The thickness of the first liquid on the optical axis is t2. Thus, the application of the voltage to the first liquid 121 changes the balance of the interfacial tension between the two liquids, and changes the shape of the interface between the two liquids. Therefore, an optical element in which the shape of the interface 124 can be freely changed by controlling the voltage of the power supply unit 126 can be realized. Further, since the first and second liquids have different refractive indices, power as an optical lens is given. Therefore, the optical element 101 is different from the varifocal lens by the shape change of the interface 124. Become. Further, since the radius of curvature is shorter at the interface 124 in FIG. 3 than in FIG. 2, the focal length of the optical element 101 in the state of FIG. 3 is shorter than in the state of FIG. .

FIG. 4 is a diagram conceptually illustrating a deformation process of the interface 124 of the optical element 101 when a DC voltage is generated from the power supply means 126. In FIG. 7A, a step-like DC voltage having a voltage value V ₀ is applied to the optical element 101 at time t ₀ . At this time, the interface of the optical element 101 shows a response like a curve shown in FIG. That is, it rises at a predetermined time constant, reaches a value of 95% of the final deformation amount δ ₀ at time t ₁₂ , and further approaches ascending toward δ _0. Decrease. This is due to the fact that charges are gradually injected into the insulating layer 104 in FIG. 3 to reduce the electrocapillary phenomenon. In order to avoid this phenomenon, the power supply means 126
Computes Renders des Sea should use an AC power supply of about 50 to 3 kHz.
nces dei'Academie des Sci
ence 317 (1993), page 158. Note that δ conceptually represents the amount of interface deformation, not a numerical value directly representing the height or contact angle of the interface, but the strength of the electrocapillary phenomenon.

FIG. 5 is a diagram conceptually illustrating a deformation process of the interface 124 of the optical element 101 when an AC voltage is generated from the power supply means 126. In FIG. 7A, when a sinusoidal AC voltage having a predetermined frequency and a maximum frequency V ₀ is applied to the optical element 101 at time t ₀ , the interface of the optical element 101 has a response like a curve shown in FIG. Is shown. That is, FIG. 4 similarly to the rise with a predetermined time constant, to reach 95% of the final deformation amount [delta] _sine at time t _12. Then, asymptotically toward δ _sine over time, the amount of deformation does not decrease thereafter.

As described above, the optical element 101 has different response characteristics at the time of interface deformation depending on the driving frequency of the power supply means. FIG. 6 conceptually shows the frequency of the voltage output from the power supply means and the deformation response of the interface 124 of the optical element 101. In this figure, the horizontal axis represents the frequency of the AC voltage supplied from the power supply unit to the optical element 101, the vertical axis represents the interface deformation speed at the start of power supply, the amount of interface deformation after a sufficient time has elapsed from the start of power supply, and the power supply. The power consumed by the means.

[0018] According to those figures, the driving frequency can not be obtained a predetermined amount of deformation phenomena of the Figure 4 occurs when the f _1,
It is not suitable for accurately controlling the optical state of the optical element 101. Predetermined deformation amount when the driving frequency f ₂ is obtained, deformation (response) speed is relatively slow. Drive frequency is f ₃
In this case, a predetermined amount of deformation is obtained, and the deformation speed is high. Predetermined deformation amount when the driving frequency f ₄ can not be obtained.
This means that the optical element can be regarded as a capacitor having a predetermined capacitance. However, since the resistance of the transparent electrode 103 and the ionic mobility of the electrolyte 122 have finite values, when the driving frequency becomes high, the optical element 101 This is because charge injection is suppressed and the electrocapillary phenomenon does not effectively appear. That is, in order to effectively control the optical element 101, it is necessary to appropriately set a power supply condition for driving the optical element 101.

FIGS. 7 and 8 are explanatory views relating to the power supply means of the first embodiment of the present invention. FIG. 7 is a diagram showing a cross section of the optical element of the present embodiment and a configuration of the power supply means. In FIG.
Reference numeral 130 denotes a central processing unit (hereinafter abbreviated as CPU) for controlling the operation of the entire optical device 150 described later.
AM, EEPROM, A / D conversion function, D / A conversion function, PWM (Pulse Width Modulant)
ion) A one-chip microcomputer having a function. 131
Is a power supply unit for applying a voltage to the optical element 101, and its configuration will be described below.

Reference numeral 132 denotes a DC power supply such as a dry battery incorporated in the optical device 150; 133, a DC / DC converter for boosting a voltage output from the power supply 132 to a desired voltage value in accordance with a control signal of the CPU 130; And 135
Is a control signal of the CPU 130, for example, PWM (Pulse
This is an amplifier that amplifies the signal level to a voltage level boosted by the DC / DC converter 133 according to a variable frequency / duty ratio signal that realizes a Width Modulation function. 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.

That is, in response to the control signal of the CPU 130, the output voltage of the power
3. The amplifier 134 and the amplifier 135 apply the desired voltage value, frequency, and duty to the optical element 101.

FIG. 8 is a diagram for explaining voltage waveforms output from the amplifiers 134 and 135. The following description is based on the assumption that a voltage of 100 V is output from the DC / DC converter 133 to the amplifiers 134 and 135, respectively. As shown in FIG. 8A, the amplifiers 134 and 135 are connected to the optical element 101, respectively. From the amplifier 134, as shown in FIG.
, A rectangular waveform voltage is output at a desired frequency and a desired duty ratio. On the other hand, FIG.
As shown in (c), by the control signal of the CPU 130,
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. Accordingly, the voltage applied between the transparent electrode 103 and the rod-shaped electrode 125 of the optical element 101 becomes 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 unit 131.

The effective value from the start of the application of the voltage applied to the optical element 101 can be expressed as shown in FIG. In the above description, it has been described that a rectangular waveform voltage is output from the amplifiers 134 and 135. However, it is needless to say that a sine wave has the same configuration. In the above description, the case where the power supply 132 is incorporated in the optical device 150 has been described. However, a case where an alternating current is applied to the optical element 101 by an external power supply or a power supply unit may be used.

FIG. 9 shows an example in which the optical element 101 is applied to an optical device. In the present embodiment, a description will be given of an example of a so-called digital still camera in which the optical device 150 photoelectrically converts a still image into an electric signal by an imaging unit and records this as digital data. An imaging optical system 140 includes a plurality of lens groups, and includes a first lens group 141 and a second lens group 1.
42 and an optical element 101. Focus adjustment is performed by moving the first lens group 141 back and forth in the optical axis direction. Zooming is performed by the power change of the optical element 101. In order to perform zooming of the photographing optical system, it is usually necessary to change the power of a plurality of lens groups and move the groups. However, in this figure, the zooming operation is represented by the power change of the optical element 101 for simplicity. I have. The second lens group 142 is a relay lens group that does not move. Then, the first lens group 1
The optical element 101 is arranged between the first lens group 141 and the second lens group 142, and the aperture of the diaphragm is adjusted between the first lens group 141 and the optical element 101 by a known technique to adjust the light amount of the photographing light beam. An aperture unit 143 is provided. An imaging unit 144 is arranged at a focal position (planned image plane) of the photographing optical system 140. This is a photoelectric conversion means such as a two-dimensional CCD comprising a plurality of photoelectric conversion units for converting irradiated light energy into electric charges, a charge storage unit for storing the electric charges, and a charge transfer unit for transferring the electric charges and sending them to the outside. Is used.

Reference numeral 145 denotes an image signal processing circuit.
A / D conversion of the analog image signal input from 44,
Image processing such as AGC control, white balance, γ correction, and edge enhancement is performed. Reference numeral 146 denotes a temperature sensor that measures the environmental temperature (air temperature) of the optical device 150. 147 is CP
In a lookup table provided in a memory area inside the U130, duty ratio data of an output voltage of the power supply unit 131 necessary for controlling the optical power of the optical element 101 to a predetermined value is stored in a form of a correspondence table. ing. Fifteen
Reference numeral 1 denotes a display such as a liquid crystal display, which displays a subject image acquired by the imaging unit 144 and an operation state of an optical device having a variable focus lens. 152 is a main switch for activating the CPU 130 from the sleep state to the program execution state, and 153 is a zoom switch. Reference numeral 154 denotes an operation switch group other than the above switches, which includes a shooting preparation switch, a shooting start switch, a shooting condition setting switch for setting shutter time, and the like.

Reference numeral 155 denotes a focus detecting means, preferably a phase difference detecting type focus detecting means used in a single-lens reflex camera. Reference numeral 156 denotes a focus driving unit, which is a first lens group 14.
It includes an actuator and a driver circuit for moving the lens 1 in the optical axis direction, and performs a focus operation based on the focus signal calculated by the focus detection means 155 to adjust the focus state of the photographing optical system 140. 157 is a memory means,
The captured image signal is recorded. Specifically, a removable PC card type flash memory or the like is preferable.

FIG. 10 is a control flowchart of the CPU 130 included in the optical device 150 shown in FIG. Hereinafter, FIG.
The control flow of the optical device 150 will be described with reference to FIG. In step S101, the main switch 15
It is determined whether or not No. 2 has been turned on, and if it has not been turned on, it is in a standby mode state of waiting for the operation of various switches. If it is determined in step S101 that the main switch 152 has been turned on, the standby mode is released, and the process proceeds to step S102 and subsequent steps.

In step S102, the temperature sensor 14
6, the ambient temperature at which the optical device 150 is placed, that is, the ambient temperature around the optical device 150 is measured. In step S103, the photographer sets the photographing conditions. For example, setting of the exposure control mode (shutter priority A
E, program AE, etc.), image quality mode (size of recording pixels, size of image compression ratio, etc.), strobe mode (forced emission, emission inhibition, etc.) are set.

In the step S104, it is determined whether or not the photographer has operated the zoom switch 153. If the ON operation has not been performed, the process proceeds to step S105. If the zoom switch 153 has been operated here, the process proceeds to step S121. In step S121, the operation amount of the zoom switch 153 (operation direction, ON time, and the like) is detected. In step S122, a focal length control target value of the photographing optical system 140 is calculated based on the operation amount. In step S123, the lookup table 147 in the CPU 130 corresponds to the focal length control target value.
The duty ratio of the voltage applied to the optical element 101 is read. The deformation amount of the optical element 101 with respect to the duty ratio will be described later with reference to FIGS. Step S12
In step 4, power supply from the power supply means 131 to the optical element 101 is started at the above duty ratio, and the process returns to step S103.
That is, while the operation of the zoom switch 153 is continued, a signal having a predetermined duty ratio corresponding to the operation amount is output to the optical element 101.
At the time when the ON operation of the zoom switch 153 is completed, the process proceeds to step S105.

In step S105, the photographing preparation switch (FIG. 10) of the operation switches 154 is operated 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 S103, and the reception of the shooting condition setting and the determination of the operation of the zoom switch 153 are repeated. Step S1
If it is determined in step 05 that the shooting preparation switch has been turned on, the process proceeds to step S111.

In step S111, the image pickup means 144 and the signal processing circuit 145 are driven to obtain a preview image. The preview image is an image acquired before shooting in order to appropriately set the shooting conditions of the image for final recording and to allow the photographer to grasp the shooting composition. In step S112, the light receiving level of the preview image acquired in step S111 is recognized. Specifically, the maximum, minimum, and average output signal levels of the image signal output by the imaging unit 144 are calculated, and the amount of light incident on the imaging unit 144 is recognized.

In step S113, step S1 is performed.
Based on the amount of received light recognized in step 12, the aperture unit 143 provided in the photographing optical system 140 is driven to adjust the aperture diameter of the aperture unit 143 so as to obtain an appropriate amount of light. In step S114, the preview image acquired in step S111 is displayed on the display 151. Then step S
At 115, the photographing optical system 1 is
Forty focus states are detected. Subsequently, in step S116, the first lens group 1 is
The focusing operation is performed by moving the lens 41 forward and backward in the optical axis direction. Thereafter, the process proceeds to step S117, and it is determined whether or not the photographing switch (in FIG. 10, denoted by SW2) is turned on. Step S11 when the on operation is not performed
Returning to step 1, the 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 repeatedly performed, the process jumps from step S117 to step S131.

In step S131, an image is taken. That is, the subject image formed on the imaging unit 144 is photoelectrically converted, and charges proportional to the intensity of the optical image are accumulated in the charge accumulation units near each light receiving unit. In step S132, the charge accumulated in step S131 is read out via the charge transfer line, and the read analog signal is read by the signal processing circuit 1.
45. In step S133, the signal processing circuit 145 converts the input analog image signal into an A / D signal.
The image data is converted and subjected to image processing such as AGC control, white balance, gamma correction, and edge enhancement.
JPEG compression or the like is performed by an image compression program stored in 130. In step S134, the above step S1
The image signal obtained at 33 is recorded in the memory 157. In step S135, first, the preview image displayed in step S114 is deleted, and the image signal obtained in step S133 is displayed again on the display 151. In step S136, the power supply output from the power supply unit 131 is stopped, and in step S137, a series of photographing operations ends.

Next, the operation in step S123 in FIG. 10 will be described with reference to FIGS. FIG.
FIG. 4 is a diagram illustrating a control method of a power supply unit and a description of an effect thereof when a large deformation is applied to an interface 124 of the optical element 101 to shorten the focal length of the optical element 101. FIG. 8A shows a voltage waveform output from the power supply unit 131 and applied to the optical element 101, and its definition is the same as that described with reference to FIG. This waveform has a peak voltage of ± V ₀ [V],
This is a rectangular wave AC voltage having a frequency of 1 kHz and a duty ratio of 100%. At this time, the effective voltage applied to the optical element 101 becomes V ₀ as shown in FIG.
Is a predetermined amount of deformation δ _{1 as} shown in FIG.
And settle.

FIG. 1 is a diagram for explaining a control method of the power supply means and its effect when the amount of deformation applied to the interface 124 of the optical element 101 is smaller than that in FIG. FIG.
This is a voltage waveform output from the power supply unit 131 and applied to the optical element 101. This waveform has a peak voltage of FIG.
± V ₀ [V], the frequency is 1 kHz, and the duty ratio is 50%. At this time,
The effective voltage applied to the optical element 101 is 0.5 V _{0 as} shown in FIG. 1B, and the deformation of the interface 124 is shown in FIG.
As shown in FIG. 11, about half of the deformation amount in FIG.
To settle at 5δ _1.

That is, in this embodiment, the peak voltage and the frequency of the drive voltage output from the power supply means are always constant, and the duty ratio is made variable to control the effective voltage supplied to the optical element 101, 124 is controlled. The driving frequency is 1 kHz in this embodiment.
And the, corresponding to a frequency near f ₃ in FIG.
By selecting such a frequency, the optical power of the optical element 101 can be rapidly and stably changed.

According to the first embodiment, (1) the configuration of the power supply means can be simplified by fixing the peak value and frequency of the drive voltage output from the power supply means and making only the duty ratio variable. Power supply means suitable for digital control using a microcomputer or the like can be provided. As a result, the optical characteristics of the optical element can be accurately controlled with an inexpensive control circuit. (2) Since the output frequency of the power supply means is selected to be higher than the frequency at which charge injection into the insulating layer of the optical element occurs and lower than the frequency at which charge transfer is impeded by an increase in impedance, the interface is stably deformed. It is possible to make it. Etc. are achieved. In the present embodiment, as an example of the optical device, a digital still camera that photoelectrically converts an image and records the data is described. However, a video camera, a silver halide camera that records an image on a silver halide film, and the like are also used. Needless to say, it can be applied without impairing the effect.

[Second Embodiment] In the first embodiment, an AC voltage having a constant peak voltage and a constant frequency is applied to an optical element, and the duty of the AC signal is changed to change the interface of the optical element into a desired shape. This is the embodiment. On the other hand, in a second embodiment, an AC voltage having a constant peak voltage and a constant duty is applied to an optical element, and the interface of the optical element is changed into a desired shape by changing the frequency of the AC signal.

FIGS. 12 to 15 are views for explaining the present embodiment. FIG. 12 is a view showing the configuration of an optical apparatus according to the present embodiment. FIG. 2 is a diagram showing a digital still camera 250 provided with.

The difference between the optical device 250 of the present embodiment and the optical device 150 of the first embodiment is that the look-up table 247 of the CPU 230 supplies power necessary for controlling the optical power of the optical element 101 to a predetermined value. Means 131
Is stored in the form of a correspondence table. Except for this, the configuration and operation are the same as those of the first embodiment, and a detailed description thereof will be omitted.

FIG. 13 is a control flowchart of the CPU 230 included in the optical device 250 according to the second embodiment. This flowchart differs from the flowchart of FIG. 10 in the first embodiment only in the data read-out portion from the lookup table 247. Hereinafter, only this changed portion will be described. In step S204, the zoom switch 15
It is determined whether or not No. 3 has been operated, and if the switch 153 has been operated, the flow proceeds to step S221.

In step S221, the zoom switch 1
The amount of operation (operation direction, ON time, etc.) of 53 is detected. In step S222, the photographing optical system 1 is set based on the operation amount.
Forty focal length control target values are calculated. Step S22
3, the lookup table 247 in the CPU 230
The optical element 1 corresponding to the focal length control target value
The frequency of the power supply signal applied to 01 is read. The deformation amount of the optical element 101 with respect to the frequency is shown in FIGS.
5 will be described. In step S224, power supply from the power supply unit 131 to the optical element 101 is started at the above frequency, and the process returns to step S203.

Next, referring to FIG. 13 and FIG.
The operation in step S223 will be described. FIG.
Gives a large deformation to the interface 124 of the optical element 101,
FIG. 4 is a diagram illustrating a control method of a power supply unit when the focal length of the optical element 101 is shortened, and an effect thereof. FIG.
Is a voltage waveform output from the feeding means 131 and applied to the optical element 101, and its definition is the same as that described with reference to FIG. 8D or FIG. 1A and FIG. This waveform has a peak voltage of ± V ₀ [V] and a frequency of 2
It is a rectangular wave AC voltage having a kHz and a duty ratio of 100%. At this time, the effective voltage applied to the optical element 101 becomes V _{0 as} shown in FIG. 11B, and the deformation of the interface 124 is settled at a predetermined deformation amount δ ₂ as shown in FIG. 11C.

FIG. 15 is a diagram for explaining a control method of the power supply means and its effect when the amount of deformation applied to the interface 124 of the optical element 101 is smaller than that in FIG. FIG.
Is a voltage waveform output from the power supply unit 131 and applied to the optical element 101. This waveform has a peak voltage of ± V ₀ [V] similar to that of FIG.
0%, the frequency is a double-wave 4 kHz rectangular wave AC voltage. At this time, the effective voltage applied to the optical element 101 is V ₀ as in FIG. 14B, but the deformation of the interface 124 is about half of the deformation amount in FIG. 14 as shown in FIG.
That is to settle in 0.5δ _2.

[0045] This is because those embodiments are used frequencies near f ₄ in Fig. That is, when the supply voltage is higher than a predetermined value, the optical element 101 is
This is because it becomes difficult to supply the electric charge for deforming the liquid crystal, and the occurrence of the electrocapillary phenomenon is suppressed. Therefore, the amount of deformation of the interface 124 decreases as the driving frequency increases, so that the optical power of the optical element 101 can be controlled to a desired value by controlling the driving frequency.

According to the second embodiment, (1) the configuration of the power supply means can be simplified by fixing the peak value and the duty ratio of the drive voltage output from the power supply means and making only the frequency variable. Control means suitable for digital control using a microcomputer or the like can be provided. As a result, the optical characteristics of the optical element can be accurately controlled with an inexpensive control circuit.

(2) Since the output frequency of the power supply means is selected to be higher than the frequency at which charge transfer to the optical element is inhibited, it is possible to deform the interface accurately and continuously by changing the frequency. . Etc. are achieved. Although a digital still camera has been described as an example of the optical apparatus in this embodiment, it is needless to say that the present invention can be applied to other video cameras, silver halide cameras, and the like without impairing the effects.

Third Embodiment FIGS. 16 to 21 are diagrams for explaining a third embodiment of the present invention.
FIG. 7 is an explanatory diagram relating to an optical element and a power supply unit used in the present embodiment. FIG. 16 is a cross-sectional view illustrating the configuration of the optical element according to the present embodiment and a configuration of a power supply unit that drives the optical element. The configuration of the optical element will be described with reference to FIG. FIG.
6, reference numeral 801 denotes the entire optical element of the present embodiment;
802 is a disc-shaped transparent acrylic or glass first
It is a sealing plate. Reference numeral 803 denotes an electrode ring, whose outer diameter is uniform, and whose inner diameter gradually changes downward. That is, in this embodiment, the inner diameter is a metal ring-shaped member whose diameter gradually increases downward.
An insulating layer 804 made of acrylic resin or the like is closely formed on the entire inner surface of the electrode ring 803. Since the inner diameter of the insulating layer 804 is uniform, the thickness gradually increases downward. Then, a water-repellent agent is applied to the lower side of the entire inner surface of the insulating layer 804 to form a water-repellent film 811, and a hydrophilic agent is applied to the upper side of the entire inner surface of the insulating layer 804, A hydrophilic film 812 is formed.

Reference numeral 806 denotes a disk-shaped second sealing plate made of transparent acrylic or glass, a part of which is provided with a hole.
The rod-shaped electrode 825 is inserted here and sealed with an adhesive. Reference numeral 807 denotes an aperture plate for limiting the diameter of a light beam incident on the optical element 801, which is fixed on the upper surface of the second sealing plate 806. The first sealing plate 802, the metal ring 803, and the second sealing plate 806 are adhered and fixed to each other to form a sealed space of a predetermined volume surrounded by these members, that is, a housing having a liquid chamber. You. This housing is provided with the rod-shaped electrode 825.
The portion other than the insertion portion has an axially symmetric shape with respect to the optical axis 823. The liquid chamber is filled with the following two types of liquids.

First, the second liquid 82 is placed on the bottom side of the liquid chamber.
2 is dropped by an amount such that the height of the liquid column is the same as the height of the water-repellent film 811 forming portion. The second liquid 822 is a colorless and transparent silicone oil having a specific gravity of 1.06 and a refractive index of 1.38 at room temperature. Subsequently, the remaining space in the liquid chamber is filled with the first liquid 821. First liquid 8
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. Further, the first liquid 82
To 1 is added an achromatic water-soluble dye, for example, carbon black or a titanium oxide-based material. That is, the first
As the second liquid, liquids having the same specific gravity and the same refractive index, different light absorption efficiencies, and insoluble in each other are selected. Therefore, both liquids form an interface 824, and each of them exists independently without being mixed. The shape of the interface 824 is determined by the balance of three interfacial tensions acting on the point where the three substances of the liquid chamber wall, the first liquid, and the second liquid intersect, that is, the outer edge of the interface 824. In this embodiment, the materials of the water-repellent film 811 and the hydrophilic film 812 are selected such that the contact angles of the first and second liquids with the inner wall of the liquid chamber are both 90 degrees.

Reference numeral 131 denotes a power supply means 131 shown in FIG.
Since these members have the same configuration and operation as those described above, detailed description thereof will be omitted. The amplifier 134 of the feeding means 131 is connected to the metal ring 803, and the amplifier 135 is connected to the rod-shaped electrode 825.
Connected to. In this structure, a voltage is applied to the first liquid 821 via the rod-shaped electrode 825, and the interface 824 is deformed by an electrowetting effect.

Next, the deformation of the interface 824 of the optical element 801 and the optical action brought about by the deformation will be described with reference to FIG. First, the first liquid 821
When no voltage is applied to the interface 824, the shape of the interface 824 becomes flat as described above (FIG. 17A). Here, the second liquid is substantially transparent, but the first liquid has a predetermined light absorbing efficiency due to the added light absorbing material.
Then, when a light beam is incident from the opening of the aperture plate 807,
Light rays are absorbed by an amount corresponding to the optical path length of the first liquid, and the intensity of the light beam emitted from the second sealing plate 802 is uniformly reduced.

On the other hand, when a voltage is applied to the first liquid, the shape of the interface 824 becomes spherical due to the electrowetting effect (FIG. 17B). Therefore, the light flux incident from the aperture of the aperture plate 807 also changes in absorptance at a rate corresponding to the change in the optical path length of the first liquid, and the intensity of the light flux emitted from the second sealing plate 802 changes from the center to the periphery. , And the average intensity is higher than in the case of FIG. That is, by changing the shape of the interface 824 by controlling the voltage of the power supply unit 131, an optical element that can freely change the amount of transmitted light can be realized. In addition, since the refractive indices of the first and second liquids are equal and only the intensity of the emitted light is changed without changing the direction of the incident light, the aperture means for adjusting the light quantity of the incident light, -Can be used for an optical shutter that blocks light.

Note that 2 by electrowetting
The principle of deformation of the liquid interface is described in the aforementioned International Patent WO99 / 184.
56, the interface 824 of this embodiment corresponds to the positions A and B of the two-liquid interface described in FIG. 6 of the patent. The principle of adjusting the amount of transmitted light of the incident light beam due to the deformation of the interface between the two liquids and the effect thereof are described in Japanese Patent Application No. 11-111,197.
No. 169657.

FIG. 18 shows an optical element 801 applied to an optical device. In this embodiment, similar to the first embodiment,
The optical device 150 will be described as an example of a so-called digital still camera that photoelectrically converts a still image into an electric signal by an imaging unit and records this as digital data. The detailed description of the same components as those in the first embodiment is omitted.

In FIG. 18, reference numeral 430 denotes a photographing optical system including a plurality of lens groups, which includes a first lens group 431, a second lens group 432, and a fourth lens group 433. Focus adjustment is performed by moving the first lens group 431 in the optical axis direction. Zooming is performed by the reciprocation of the second lens group 432 in the optical axis direction. The fourth lens group 433 is a relay lens group that does not move. Then, the optical element 801 is arranged between the second lens group 432 and the fourth lens group 433. An imaging unit 144 is arranged at a focal position (planned image plane) of the imaging optical system 440.

Next, the operation of the optical element 801 in this embodiment will be described. The dynamic range of the luminance of a subject existing in the natural world is very large, and in order to keep the dynamic range within a predetermined range, a mechanical diaphragm mechanism is usually provided inside the photographing optical system to adjust the light amount of the photographing light beam. However, it is difficult to reduce the size of the mechanical aperture mechanism, and in a small aperture state where the aperture opening is small, the resolution of the subject image is reduced due to the diffraction phenomenon of light rays by the end face of the aperture blade. Therefore, in this embodiment, by using the optical element 801 as a variable ND filter that substitutes for the mechanical diaphragm mechanism, the amount of light passing through the photographing optical system is appropriately adjusted without causing the above-described disadvantage.

FIG. 19 shows the optical device 350 shown in FIG.
FIG. 7 is a control flowchart of a CPU 330 included in the CPU. Hereinafter, a control flow of the optical device 350 will be described with reference to FIGS. A detailed description of the same control flow as in the first embodiment will be omitted. In step S301,
It is determined whether or not the main switch 152 has been turned on by the photographer.
Stay at 01. In step S301, the main switch 15
If it is determined that No. 2 has been turned on, the CPU 330 exits the sleep state and executes the steps from step S302.

In step S302, as in the first embodiment,
The temperature sensor 146 measures the environmental temperature where the optical device 350 is placed, that is, the ambient temperature around the optical device 350. In step S303, the photographer sets the photographing conditions. In step S304, a photographing preparation switch by the photographer (in the flowchart, denoted as SW1)
It is determined whether or not the ON operation has been performed. If the ON operation has not been performed, the process returns to S303, and the determination of the reception of the shooting condition setting is repeated.

If it is determined in step S304 that the photographing preparation switch has been turned on, the flow advances to step S311. Steps S311 and S312 are the same as in the first embodiment, and a description thereof will be omitted. Step S31
In 3, it is determined whether or not the amount of received light determined in step S312 is appropriate. If it is determined in this step that it is appropriate, the process proceeds to step S314.

On the other hand, if it is determined in step S313 that the amount of received light determined in step S312 is not appropriate, the process jumps to step S321. Step S3
In 21, the actual amount of received light is compared with an appropriate amount of received light, and an appropriate transmittance to be given to the optical element 801 in the imaging optical system 430 is calculated. In step S322, step S321
The voltage to be applied to the optical element 801 is calculated in order to obtain the appropriate transmittance calculated in. Specifically, the ROM of the CPU 330, the relationship of the transmittance with respect to the applied voltage so stored as a look-up table 347, by referring to the table to determine the applied voltage V ₃ for the calculated transmittance in step S321 . That is, in order to control the amount of interface deformation of the optical element, the duty ratio of the AC output from the power supply unit is switched in the first embodiment, and the frequency is switched in the second embodiment, but the peak voltage is switched in the third embodiment. .

In step S323, an AC voltage having a peak voltage of ± V3 and a first frequency is applied to the optical element 801 from the power supply means. Here, in this embodiment, the first frequency is set to 1 kHz. Then, the interface 824 of the optical element 801 is deformed into a predetermined shape in accordance with the effective value of the input voltage, and the light transmittance of the element 801 is controlled to a desired value.

After execution of step S323, step S31 is executed.
Returning to step 1, the steps from the acquisition of the image signal in step S311 to step S323 are repeatedly executed until the amount of light incident on the imaging unit 144 becomes appropriate. When the amount of light incident on the imaging unit 144 becomes appropriate, the process proceeds from step S313 to step S314. Step S
At 314, the frequency of the AC signal output from the power supply means 131 is switched to the second frequency. In this embodiment, the second frequency is set to 250 Hz, but the effect of this switching will be described later with reference to FIGS.

In step S315, step S311
Is displayed on the display 151.
Subsequently, in step S316, the focus state of the imaging optical system 430 is detected using the focus detection unit 155. Subsequently, in step S317, the focus driving unit 156 moves the first lens group 431 in the optical axis direction to perform a focusing operation. Thereafter, the process proceeds to step S318, and it is determined whether or not the photographing switch (in FIG. 19, described as SW2) is turned on. If the ON operation has not been performed, the process returns to step S311, and steps from acquisition of the preview image to focus driving are repeatedly executed.

As described above, if the photographer turns on the photographing switch while the photographing preparation operation is being repeatedly executed, the process jumps from step S318 to step S331. In step S331, the frequency of the AC signal output from the power supply unit 131 is switched to the first frequency. That is, the frequency is returned from 250 Hz to 1 kHz. In step S332, imaging is performed. That is, the imaging unit 144
The subject image formed above is subjected to photoelectric conversion, and electric charges proportional to the intensity of the optical image are accumulated in electric charge accumulating units near each light receiving unit.
In step S333, the charge accumulated in step S131 is read out via the charge transfer line, and the read-out analog signal is input to the signal processing circuit 145. In step S334, the signal processing circuit 145 performs A / D conversion on the input analog image signal, and performs AGC control.
Image processing such as white balance, gamma correction, and edge enhancement is performed, and JPEG compression or the like is performed as necessary using an image compression program stored in the CPU 330. In step S335, the image signal obtained in step S334 is recorded in the memory 157. In step S336,
First, the preview image displayed in step S315 is deleted, and the image signal obtained in step S334 is displayed on the display 1
51 is displayed again. In step S337, the power supply output from the power supply unit 131 is stopped, and a series of photographing operations ends in step S338.

Next, the operation and effect of switching the frequency of the power supply means output will be described with reference to FIGS. 20 and 21. FIG.
Means that the output of the power supply means 131 is at the first frequency,
It is a figure explaining the control method of the electric power feeding means in the case of kHz, and its effect. FIG. 8A shows a voltage waveform output from the power supply unit 131 and applied to the optical element 101, and its definition is the same as that described with reference to FIG. This waveform is a rectangular wave AC voltage having a peak voltage of ± V ₃ [V], a frequency of 1 kHz, and a duty ratio of 100%. Here frequency 1kHz in is equivalent to f ₃ in FIG. 6. At this time, the effective voltage applied to the optical element 101 is as shown in FIG.
As shown in (b), the voltage becomes V ₃ , and the power consumption in the power supply means 131 is as shown in FIG. That is, the optical element 801
Since the capacitor has a capacitor structure, the inflow current decreases with the accumulation of electric charge after the application of a constant voltage, so that the power consumption repeats a fine fluctuation synchronously with the switching of the polarity of the power supply voltage as shown in FIG. . It is assumed that the peak value of the power consumption at this time is W30 and the average value is W31. In addition, interface 8
24 is deformed with the waveform shown in FIG.

FIG. 21 is a diagram for explaining a control method of the power supply means and its effect when the output of the power supply means 131 is at the second frequency, that is, 250 Hz.
Has the same meaning as FIG. 3A shows a voltage waveform output from the power supply unit 131 and applied to the optical element 101.
The peak voltage is the same ± V ₃ [V] as in FIG. 20, the duty ratio is the same as in FIG. 20, 100%, and the frequency is a 250 Hz rectangular wave AC voltage. Here, the frequency of 250 Hz corresponds to f ₂ in FIG. At this time, the effective voltage applied to the optical element 101 is V ₃ as shown in FIG. 21B, and the power consumption in the power supply means 131 is as shown in FIG. That is, since the frequency of the signal supplied to the optical element 801 decreases, the power consumption fluctuates more than that shown in FIG. W ₃₂ power consumption average Thus Figure 20
Lower than the case. The interface 824 is deformed with the waveform shown in FIG. 20D, but the interface deformation speed at this time is lower than that in FIG. However, after the amount of surface deformation is settled to a predetermined value [delta] _3, the interface shape is stabilized.

As described above, when the AC signal applied to the optical element 801 is set to a high frequency, the power consumption is large but the response speed of the interface is fast. When the signal is set to a low frequency, the response is slow but the power consumption is small. I can do it. Therefore, in this embodiment, as shown in step S323 of FIG. 19, when the interface shape of the optical element is changed, a high frequency is applied to enable quick deformation. On the other hand, step S31 in FIG.
As shown in FIG. 4, when the deformation is completed and the predetermined shape is maintained, the driving frequency is switched to a low frequency to achieve power saving. In this case, since the deformation of the interface 824 has already been completed, the slow response speed of the interface does not hinder at all. Further, in the present embodiment, step S in FIG.
As shown at 331, the driving frequency is returned to the high frequency immediately before the photographing operation. This has the effect of strengthening the interface restraining force of the optical element at the time of photographing and reducing fluctuations in optical characteristics due to disturbance during photographing. Also, because the shooting time is short,
The increase in power consumption is not a major obstacle.

According to the third embodiment, (1) the frequency of the drive signal output from the power supply means is appropriately switched according to the state of the optical device, so that the power supply is performed without sacrificing the deformation speed of the optical element. Power saving of means can be achieved. (2) A high-frequency drive signal is supplied when high stability is required for the optical element, and a low-frequency drive signal is supplied when high stability is acceptable, thereby deteriorating the performance of the optical device. Power saving of power supply means can be achieved without causing Etc. are achieved. In this embodiment, a digital still camera is taken as an example of the optical device. However, it goes without saying that the present invention can be applied to other video cameras, silver halide cameras, and the like without impairing the effects. Further, the optical element 801 of this embodiment
The same effect can be obtained by applying the power supply control method of Example 1 to Example 1 and Example 2, and the same effect can be obtained by applying the power supply control method of Example 1 and Example 2 to Example 3. can get.

[0070]

As described above, according to the invention of the present application, since the characteristics of the optical element are changed by changing the duty ratio of the AC signal of the rectangular wave applied to the optical element, the power supply means is particularly required to be a micro power supply. The configuration of the power supply means in a device digitally controlled using a computer can be made simple and inexpensive. Also, the optical characteristics can be accurately controlled with high resolution.

According to another aspect of the present invention, the characteristics of the optical element are changed by changing the frequency of the rectangular wave AC signal applied to the optical element. In a digitally controlled device, the configuration of the power supply means can be made simple and inexpensive. Also, the optical characteristics can be accurately controlled with high resolution.

According to another aspect of the present invention, the frequency of the rectangular wave AC signal applied to the optical element is changed between when the signal is applied and when the signal is applied, so that unnecessary power is consumed. This can prevent the power of the optical device from increasing.

According to another aspect of the present invention, the frequency of the AC signal of the rectangular wave applied to the optical element is changed depending on whether high stability is required for the optical element or not. Power consumption can be prevented, and the life of the power supply of the optical device can be extended.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a power supply control method for an optical element according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the optical element according to the first embodiment of the present invention.

FIG. 3 is an operation explanatory diagram when a voltage is applied to the optical element according to the first embodiment of the present invention.

FIG. 4 is an operation explanatory diagram when a DC voltage is applied to the optical element of the present invention.

FIG. 5 is an operation explanatory diagram when an AC voltage is applied to the optical element of the present invention.

FIG. 6 is a conceptual diagram of a driving frequency and a response in the optical element of the present invention.

FIG. 7 is an explanatory diagram of an optical element and a power supply unit according to the first embodiment of the present invention.

FIG. 8 is an explanatory diagram of an operation of a power supply unit according to the first embodiment of the present invention.

FIG. 9 is a configuration diagram of the optical device according to the first embodiment of the present invention.

FIG. 10 is a control flowchart of the optical apparatus according to the first embodiment of the present invention.

FIG. 11 is a diagram illustrating a power supply control method according to the first embodiment of the present invention.

FIG. 12 is a configuration diagram of an optical device according to a second embodiment of the present invention.

FIG. 13 is a control flowchart of the optical device according to the second embodiment of the present invention.

FIG. 14 is a diagram illustrating a power supply control method according to the second embodiment of the present invention.

FIG. 15 is a diagram illustrating a power supply control method according to the second embodiment of the present invention.

FIG. 16 is a sectional view of an optical element according to a third embodiment of the present invention.

FIG. 17 is an operation explanatory diagram when a voltage is applied to the optical element according to the third embodiment of the present invention.

FIG. 18 is a configuration diagram of an optical device according to a third embodiment of the present invention.

FIG. 19 is a control flowchart of the optical device according to the third embodiment of the present invention.

FIG. 20 is a diagram illustrating a power supply control method according to a third embodiment of the present invention.

FIG. 21 is a diagram illustrating a power supply control method according to a third embodiment of the present invention.

[Explanation of symbols]

 101, 801: optical element 102, 802: transparent substrate 103: transparent electrode 104, 804: insulating layer 107, 807: aperture plate 803: electrode ring 111, 811: water-repellent film 112, 812: hydrophilic film 113, 813: hydrophilic Film 121, 821: First liquid 122, 822: Second liquid 123, 823: Optical axis 124, 824: Interface 125, 825: Rod electrode 130, 230, 330: CPU 126, 131: Power supply means 132: Power 133: DC / DC converter 134, 135: amplifier 140, 430: photographing optical system 144: imaging means 146: temperature sensor 150, 250, 350: optical device 151: display 152: main switch 153: zoom switch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 13/32 G02B 7/11 Z 9A001 9/02 G03B 3/04 11/00 (72) Inventor Eriko Kawanami 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term (reference) in Canon Inc. 9A001 BB06 HH23 KK16 KK32

Claims (15)

[Claims] An electroconductive or polar first liquid and a second liquid which are not mixed with the first liquid are sealed in a container with their interfaces having a predetermined shape. An optical device having an optical element whose optical characteristics change due to a change in interface shape caused by application of a voltage to an electrode provided in the container, wherein a predetermined AC voltage is applied to the electrode in order to change the interface shape. Power supply means for applying the AC voltage, and an applied voltage control means for controlling the AC voltage to be applied, wherein the applied voltage control means controls a duty ratio of the AC voltage, and by controlling the duty ratio, An optical device, wherein the interface shape is changed. 2. The optical device according to claim 1, wherein said feeding means has a configuration for applying an AC voltage having a rectangular wave whose peak voltage and frequency are substantially constant. 3. A container for sealing a conductive or polar first liquid and a second liquid which are not mixed with each other in a container with their interfaces having a predetermined shape. An optical device having an optical element whose optical characteristics change due to a change in interface shape caused by application of a voltage to an electrode provided in the container, wherein a predetermined AC voltage is applied to the electrode in order to change the interface shape. And a voltage control means for controlling the AC voltage to be applied, wherein the applied voltage control means controls the frequency of the AC voltage, and the interface is controlled by controlling the frequency. An optical device characterized by changing its shape. 4. The optical element according to claim 3, wherein said power supply means has a configuration for applying an AC voltage which is a rectangular wave having a substantially constant duty ratio and a peak voltage. 5. A container for sealing a conductive or polar first liquid and a second liquid which do not mix with each other in a container with their interfaces having a predetermined shape. An optical device having an optical element whose optical characteristics change due to a change in interface shape caused by application of a voltage to an electrode provided in the container, for observing or recording a light beam passing through the optical element. Additional means to be used, power supply means for applying a predetermined AC signal to the electrode to change the interface shape, and power supply control means for controlling the AC signal to be applied,
An optical device, comprising: additional control means for controlling an operation of the additional means, wherein a frequency of the AC signal is switched by the power supply control means in accordance with a control state of the additional control means. 6. The power supply control means sets the AC voltage to a first frequency when voltage application to the optical element is started, and switches the AC voltage to a second frequency after the deformation of the optical element is completed. The optical device according to claim 5, wherein 7. The addition means has a photographing means, and the power supply control means sets the AC voltage to a second frequency when the photographing means prepares for photographing for recording an image, and the photographing means converts the image to an image. 7. The optical device according to claim 5, wherein the AC voltage is switched to the first frequency during photographing for recording. 8. The first liquid and the second liquid have substantially different refractive indices, and are sealed in the container with their interface in a large R shape when the voltage is not applied. The optical device according to claim 1, wherein: 9. The first liquid and the second liquid have substantially the same refractive index, and their interfaces are substantially flat when no voltage is applied. The method according to claim 1, wherein
The optical device according to Item. 10. An electrode comprising: a first electrode; and a second electrode insulated from the first liquid, wherein the first electrode is provided so as to be electrically connected to the first liquid. The optical device according to claim 1, wherein: 11. The optical device according to claim 10, wherein the first electrode is provided so as to be electrically connected to the first liquid from a side surface of the container. 12. The optical device according to claim 10, wherein the first electrode is provided so as to conduct from the upper surface side of the container to the first liquid. 13. The optical device according to claim 10, wherein the second electrode is provided on a side surface of the container. 14. The optical device according to claim 13, wherein the second electrode is a ring-shaped electrode and is arranged so as to surround the second liquid. 15. The optical device according to claim 14, wherein the ring-shaped electrode has a shape whose inner diameter gradually changes in a light beam emitting direction.