JP2006064949A - Lens unit and imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized lens unit preventing camera shake, and to provide an imaging device. <P>SOLUTION: The lens unit stores insulation liquid and conductive liquid which have mutually different refractive indexes and are mutually immiscible and have optical transparency respectively in a liquid storing container having optical transparency. Furthermore, the lens unit comprises a first electrode brought into contact with the conductive liquid; one or more second electrodes insulated to the conductive liquid; a sensor for sensing movement of the liquid storing container in a prescribed direction; and a control unit for suppressing light advance path change transmitting the liquid storing container accompanying movement of the liquid storing container by impressing voltage across the first electrode and each of a plurality of the second electrodes in response to detection result, and changing a boundary face shape between the insulation liquid and the conductive liquid. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens unit that transmits light and an imaging device that forms image of subject light to acquire image data.

  In an electronic still camera that forms an image of a subject on a solid-state image sensor such as a charge coupled device (CCD) and captures image data representing the subject as a signal, or a film camera that takes a photograph on a photographic film Some cameras have a zoom function for freely setting a shooting angle of view, and such a camera is provided with a photographing lens whose focal length changes according to the operation of a zoom switch. This photographing lens is generally a compound lens composed of a combination of a plurality of lens elements, and the relative positions of the plurality of lens elements are adjusted according to the focal length set by the zoom switch. Such a camera is equipped with a cam mechanism, and the cam mechanism transmits the rotation of the motor in response to the operation of the zoom switch, so that the plurality of lens elements move back and forth in the optical axis direction and the relative positions are adjusted. And the focal length changes.

  In addition, there is a focus lens for focus adjustment among the plurality of lens elements, and a lens driving mechanism for moving the focus lens may be provided separately from the cam mechanism.

  In recent years, in place of the above-described photographic lens having a drive mechanism, a variable focal length liquid lens in which two kinds of liquids having different refractive indexes and immiscible with each other is housed has been proposed (for example, Non-Patent Document 1).

  In the liquid lens proposed in Non-Patent Document 1, two kinds of liquids having different refractive indexes and immiscible with each other are accommodated inside, and one of these two kinds of liquids is A conductive aqueous solution and the other liquid is an insulating oil. These two kinds of liquids are accommodated in a liquid container in which both ends of a short glass tube are closed with a transparent end cap having light permeability. The inner wall of the tube and the inner wall of one end cap are covered with a water repellent film. According to the liquid lens thus configured, the conductive aqueous solution of the two types of liquid repels the inner wall of the tube covered with the water-repellent film and the inner wall of one end cap. Since the aqueous solution stays in a hemispherical shape in contact with the other end cap, the interface portion between the conductive aqueous solution and the insulating oil functions as a concave lens. The liquid lens is also provided with two electrodes for applying a voltage to the conductive aqueous solution, and one of the two electrodes is disposed in contact with the conductive aqueous solution. The other electrode is disposed on the back side of the water-repellent film. When a voltage is applied to such an electrode, an electric charge is released from the electrode disposed so as to be in contact with the aqueous conductive solution into the aqueous conductive solution, and the released charge is insulated in the aqueous conductive solution. Phenomenon that accumulates at the interface with the oil. The electric charge accumulated in the interface portion and the electric charge collected on the electrode disposed on the back side of the water-repellent film having a polarity opposite to that of the electric charge are attracted by the Coulomb force, so that the charge in the conductive aqueous solution is transferred to the water-repellent film. Attracted nearby. As a result, the conductive aqueous solution begins to wet the water-repellent film coated on the inner wall of the tube, and the interface shape of the two types of liquid changes. That is, as the voltage is applied to the conductive aqueous solution, the radius of curvature of the interface portion of the conductive aqueous solution that initially functioned as the concave lens with the insulating oil changes. It becomes flat or the conductive aqueous solution functions as a convex lens, and the focal length changes.

  According to such a liquid lens, since the focal length can be changed without moving the lens, the zoom function and the focus function can be realized without providing the cam mechanism or the lens driving mechanism described above. . Therefore, the apparatus can be significantly reduced in size, and can be applied to a small device such as a mobile phone.

  By the way, when shooting using a small camera or the like, the camera is likely to move when the release switch is pressed, causing a problem such as camera shake that causes image shift in the captured image. In recent years, holding a camera with only one hand and extending the hand to take a picture of itself has been widely performed, and camera shake is likely to occur.

As a technique for preventing this camera shake, a technique for preventing image displacement by decentering a part of the lens in a direction perpendicular to the optical axis to decenter the lens by an amount corresponding to the movement of the camera (for example, see Patent Document 1). In addition, a technique has been proposed in which a prism is provided on the optical path and its apex angle is changed by an amount corresponding to the movement of the camera (see, for example, Patent Document 2, Patent Document 3, and Patent Document 4).
"Philips' Fluid Lenses", [online], March 3, 2004, Royal Philips Electronics, [March 31, 2004 search], Internet <URL: http: // www. dpreview. com / news / 0403/040030302 philipsfluidens. asp> JP-A-7-301836 JP-A-5-134285 JP-A-5-181094 JP-A-8-6087

  However, since the above-described anti-shake technology requires a large drive mechanism and the like, when applied to the liquid lens described in Non-Patent Document 1, the device becomes large and mounted on a small device such as a cellular phone. There is a problem that it becomes impossible to do.

  In view of the above circumstances, an object of the present invention is to provide a small lens unit and an imaging apparatus that prevent camera shake.

The lens unit of the present invention that achieves the above object has at least a predetermined refractive index, a refractive index different from each other, an immiscible mutual, each having a light-transmitting property, and an insulating liquid and a conductive liquid contained therein. A liquid container that transmits light in the optical axis direction;
A first electrode in contact with the conductive liquid in the liquid container;
A plurality of second electrodes insulated from the conductive liquid in the liquid container;
A sensor for detecting movement of the liquid container in a predetermined direction;
By changing the shape of the boundary surface between the insulating liquid and the conductive liquid by applying a voltage according to the detection result by the sensor between the first electrode and each of the plurality of second electrodes, the liquid And a control unit that suppresses a change in the path of light transmitted through the liquid container as the container is moved.

  According to the lens unit of the present invention, a voltage corresponding to the movement of the liquid container is applied between the first electrode and each of the plurality of second electrodes, and the electric charge is charged from the first electrode into the conductive liquid. Are discharged, and charges having opposite polarities to the charges are collected in the plurality of second electrodes, and the charges having opposite polarities are attracted to each other by Coulomb force. As a result, the shape of the boundary surface between the conductive liquid and the insulating liquid changes to a shape corresponding to the applied voltage, and the path change of light passing through the liquid container accompanying the movement of the liquid container is suppressed. For example, when the lens unit of the present invention is applied to a camera, even if the camera moves when the photographer presses the release switch of the camera, the light path is corrected according to the movement of the camera, and imaging is performed. Since light is imaged at the correct position on the element, problems such as camera shake are avoided. Further, according to the lens unit of the present invention, there is an advantage that the path of light is corrected at high speed and silently due to the shape change of the boundary surface of the liquid, and further, a large driving mechanism such as a motor is not required. It can also be installed in small devices such as mobile phones.

  In the lens unit of the present invention, it is preferable that the conductive liquid is water and the insulating liquid is an organic solvent.

  Since there is a large difference in electrical conductivity between water and the organic solvent, the combination of these liquids changes the shape of the interface between the liquids with high accuracy and efficiency.

  In the lens unit of the present invention, the insulating liquid is preferably a hydrocarbon-based organic solvent.

  By applying the hydrocarbon-based organic solvent, the temporal stability of the lens unit is improved.

  In the lens unit of the present invention, it is preferable that the plurality of second electrodes include three or more electrodes surrounding an optical path of light transmitted through the liquid container.

  By providing three or more electrodes surrounding the optical path of light, the shape of the boundary surface between the insulating liquid and the conductive liquid is controlled from multiple directions, so that the path change of the light passing through the liquid container is accurate. Corrected well.

Further, the lens unit of the present invention includes a plurality of lens elements arranged in the optical axis direction, each having a liquid container, a first electrode, and a second electrode and having different second electrode arrangements. With
The sensor detects movement of the entire plurality of lens elements,
A controller that suppresses a change in the path of light transmitted through the plurality of lens elements as a result of movement of the plurality of lens elements by applying each voltage corresponding to the detection result of the sensor to each of the plurality of lens elements. It may be.

  In each of the plurality of lens elements, the interface between the conductive liquid and the insulating liquid is changed in different directions, so that the light passing through the lens unit is adjusted in its path when passing through each lens element. Is done.

In addition, the image pickup apparatus of the present invention that achieves the above-described object has at least an insulating liquid and a conductive liquid housed inside, each having a refractive index different from each other, immiscible with each other, and each having optical transparency. A liquid container that transmits light in a predetermined optical axis direction, a first electrode that is in contact with the conductive liquid in the liquid container, and a plurality of second electrodes that are insulated from the conductive liquid in the liquid container. A photographic optical system having a plurality of electrodes;
An image sensor that forms an image signal representing the subject light by imaging the subject light that has passed through the photographing optical system on the surface;
A sensor for detecting movement of the liquid container in a predetermined direction;
Imaging is performed by applying a voltage according to the detection result of the sensor between the first electrode and each of the plurality of second electrodes to change the shape of the boundary surface between the insulating liquid and the conductive liquid. And a control unit that suppresses a shift of an imaging position on the image sensor of subject light that has passed through the photographing optical system accompanying the movement of the optical system.

  According to the imaging apparatus of the present invention, as with the lens unit of the present invention, an increase in the size of the apparatus is suppressed, and camera shake is reduced at high speed and silently.

  Note that only the basic form of the imaging apparatus according to the present invention is shown here, but this is only for avoiding duplication, and the imaging apparatus according to the present invention is not limited to the above basic form. Various forms corresponding to the respective forms of the lens unit described above are included.

  According to the present invention, it is possible to provide a small lens unit and an imaging apparatus that prevent camera shake.

  Hereinafter, prior to describing embodiments of the present invention, the problems of the liquid lens described in Non-Patent Document 1 described above will be analyzed in detail.

  FIG. 1 is a schematic configuration diagram of a liquid lens as a comparative example. Hereinafter, light is transmitted in the direction of the arrow O, and the light incident side (upper side in FIG. 1) is referred to as the upper side, and the light emission side (lower side in FIG. 1) is referred to as the lower side.

  As shown in FIG. 1, the liquid lens 1 includes a transparent oil 21 that is an insulating liquid in a glass container 11 in which both ends of a glass tube 11a are closed with glass caps 11b and 11c. And the transparent water 22 to which the supporting electrolyte is added are contained without being mixed with each other. Since the oil 21 has a higher light refractive index than the water 22, the oil 21 serves as a lens that refracts light in the liquid lens 1.

  The inner surface of the tube 11a of the container 11 and the inner surface of the cap 11b that closes the upper end of the tube 11a are covered with a water-repellent water-repellent film 15, and the inner surface of the cap 11c that closes the lower end of the tube 11a is hydrophilic. It is covered with a hydrophilic film 16 having

  Further, an insulating film 14 is provided between the tube 11 a and the water repellent film 15, and the liquid lens 1 is insulated from the water 22 by the first electrode 12 in contact with the water 22 and the insulating film 14. A second electrode 13 is also provided.

In a state where no voltage is applied between the first electrode 12 and the second electrode 13, the water 22 repels the water-repellent film 15 and repels the hydrophilic film 16 as shown in part (A) of FIG. 1. Therefore, the contact portion P ₁ between the water 22 and the water repellent film 15 becomes small. For this reason, the water 22 stays in a hemispherical shape, and the oil 21 pushed by the water 22 stays in a shape that penetrates the hemisphere from the cylindrical shape. Since the shape of the boundary surface between the oil 21 and the water 22 when viewed from the oil 21 is concave, in the part (A), the liquid lens 1 functions as a concave lens.

For example, when a positive voltage is applied to the first electrode 12 and a negative voltage is applied to the second electrode 13, a positive charge 31 a is released from the first electrode 12 to the water 22, and a negative voltage is applied to the second electrode 13. Charge 31b accumulates. At this time, positive charges 31a released into water 22 is attracted to the negative charge 31b of the second electrode 13 by the Coulomb force, contact portion P ₂ of water 22 and the water-repellent film 15 increases in accordance with the applied voltage . In Part (B), the shape of the boundary surface between the oil 21 and the water 22 when viewed from the oil 21 is convex, and the liquid lens 1 functions as a convex lens. Moreover, the shape of the boundary surface between the oil 21 and the water 22 can be changed little by little by adjusting the voltage applied to the first electrode 12 and the second electrode 13.

  Thus, according to the liquid lens 1, the zoom function and the focus function can be realized by changing the shape of the boundary surface between the oil 21 and the water 22 without providing a mechanism for moving the lens.

  Here, when the liquid lens 1 is mounted on a camera or the like, camera shake may occur when the photographer presses the release switch. In order to avoid the influence of the camera shake, the liquid lens 1 is provided with a prism and a mechanism for changing the apex angle of the prism according to the camera shake, and the path of the light transmitted through the liquid lens 1 is adjusted. It is possible to do. However, in order to realize this method, a large drive mechanism is required, and the entire apparatus becomes large, so that the liquid lens 1 cannot be mounted on a small device such as a mobile phone.

  The present invention is based on the detailed analysis as described above.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 2 is an external perspective view of a digital camera to which an embodiment of the present invention is applied as seen from diagonally above the front.

  As shown in FIG. 2, a photographing lens 101 is provided at the center of the front surface of the digital camera 100. Further, an optical viewfinder objective window 102 and an auxiliary light emitting unit 103 are provided on the upper front of the digital camera 100. Further, a slide-type power switch 104 and a release switch 150 are provided on the upper surface of the digital camera 100.

  FIG. 3 is a schematic configuration diagram of the digital camera 100 shown in FIG.

  As shown in FIG. 3, the breakdown of the digital camera 100 is roughly divided into a photographing optical system 110 and a signal processing unit 120. In addition to these, the digital camera 100 includes an image display unit 130 for displaying captured images, an external recording medium 140 for recording captured image signals, and various processes for capturing digital cameras. A zoom switch 170, a shooting mode switch 160, a release switch 150, and a movement sensor 180 that detects the movement of the digital camera 100 are provided. The movement sensor 180 corresponds to an example of a sensor according to the present invention.

  First, the configuration of the photographing optical system 110 will be described with reference to FIG.

  In the digital camera 100, subject light enters from the left side of FIG. 3, passes through the zoom lens 116, focus lens 115, and camera shake correction lens 114, and passes through an iris 113 that adjusts the amount of subject light, and then the shutter 112. When is open, an image is formed on the solid-state image sensor 111. The solid-state image sensor 111 corresponds to an example of an image sensor according to the present invention. Originally, a plurality of lenses are provided in the photographing optical system, and at least one of the plurality of lenses is largely involved in the focus adjustment, and the relative position of each lens is involved in the focal length. A lens related to a change in focal length is schematically shown as a zoom lens 116, and a lens related to focus adjustment is schematically shown as a focus lens 115.

  The zoom lens 116, the focus lens 115, the iris 113, and the shutter 112 are driven and moved by the zoom motor 116a, the focus motor 115a, the iris motor 113a, and the shutter motor 112a, respectively. In addition, the camera shake correction lens 114 is provided with a camera shake controller 114a that changes the lens shape of the camera shake correction lens 114 instead of the motor. Instructions for operating the zoom motor 116a, the focus motor 115a, the iris motor 113a, and the shutter motor 112a are transmitted from the digital signal processing unit 120b in the signal processing unit 120 through the motor driver 120c and operate the camera shake controller 114a. The instruction to be transmitted is directly transmitted from the digital signal processing unit 120b. Further, the detection result detected by the movement sensor 180 is transmitted to the camera shake controller 114a. In the present embodiment, the movement sensor 180 includes an elevation angular velocity sensor 181 that measures the angular velocity in the elevation angle direction (vertical direction) of the digital camera 100 and an azimuth direction in which the angular velocity in the azimuth direction (left and right direction) of the digital camera 100 is measured. The angular velocity sensor 182 includes measurement results from the elevation angular velocity sensor 181 and the azimuth angular velocity sensor 182, which are transmitted to the camera shake controller 114 a. When receiving an operation instruction from the digital signal processing unit 120b, the camera shake controller 114a operates according to the detection result transmitted from the movement sensor 180.

  The zoom lens 116 is moved in a direction along the optical axis by a zoom motor 116a. When the zoom lens 116 is moved to a position corresponding to the signal from the signal processing unit 120, the focal length is changed and the photographing magnification is determined.

  The focus lens 115 is a lens for realizing a TTLAF (Through The Lens Auto Focus) function. With the TTLAF function, the contrast of the image signal obtained by the solid-state image sensor 111 is detected by the AF / AE calculation unit 126 of the signal processing unit 120 while moving the focus lens in the direction along the optical axis, and the contrast The focus lens 115 is adjusted to the focus position with the lens position where the peak is obtained as the focus position. With this TTLAF function, it is possible to automatically focus on a subject whose contrast is at a peak (that is, the closest subject closest to the subject).

  The camera shake correction lens 114 realizes a camera shake correction function for correcting the course of the subject light so that the subject light is imaged at a correct position on the solid-state image sensor 111 even when the digital camera 100 has moved. It is a lens to do. In this embodiment, the camera shake controller 114a changes the lens shape of the camera shake correction lens 114 to correct the path of the subject light. The configuration of the camera shake correction lens 114 and the method of changing the lens shape will be described in detail later.

  The iris 113 is driven based on an instruction given from the AF / AE calculation unit 126 of the digital signal processing unit 120b to adjust the amount of subject light.

  The above is the configuration of the photographing optical system 110.

  Next, the configuration of the signal processing unit 120 will be described. A subject image formed on the solid-state imaging device 111 by the photographing optical system is read as an image signal to the analog processing (A / D) unit 120a, and the analog processing unit (A / D) 120a converts the analog signal into a digital signal. It is converted and supplied to the digital signal processor 120b. A system controller 121 is provided in the digital signal processing unit 120b, and signal processing in the digital signal processing unit 120b is performed in accordance with a program showing an operation procedure in the system controller 121. Data between the system controller 121 and the image signal processing unit 122, image display control unit 123, image compression unit 124, media controller 125, AF / AE calculation unit 126, key controller 127, buffer memory 128, and internal memory 129 Is transferred via the bus 1200, and the internal memory 129 serves as a buffer when data is transferred via the bus 1200. Data serving as variables is written to the internal memory 129 as needed according to the progress of the processing process of each unit, and the system controller 121, the image signal processing unit 122, the image display control unit 123, the image compression unit 124, and the media controller 125 are written. The AF / AE calculation unit 126 and the key controller 127 perform appropriate processing by referring to the data. That is, an instruction from the system controller 121 is transmitted to each of the above units via the bus 1200, and a processing process of each unit is started. Then, the data in the internal memory 129 is rewritten in accordance with the progress of the process, and is further referred to on the system controller 121 side to manage the operation of each unit described above. In other words, the power is turned on, and the process of each unit is started according to the procedure of the program in the system controller 121. For example, when the release switch 150, zoom switch, and shooting mode switch are operated, information indicating that the switch has been operated is transmitted to the system controller 121 via the key controller 127, and processing corresponding to the operation is performed by the system controller. This is performed according to the program procedure in 121.

  When the release operation is performed, the image data read from the solid-state imaging device is converted from an analog signal to a digital signal by an analog processing (A / D) unit 120a, and the digitized image data is converted into a digital signal processing unit. Once stored in the buffer memory 128 in 120b. The RGB signal of the digitized image data is converted into a YC signal by the image signal processing unit 122, and further compression called JPEG compression is performed by the image compression unit 124 so that the image signal becomes an image file and the media controller 125 is set. To the external recording medium 140. The image data recorded as the image file is reproduced on the image display unit 130 through the image display control unit 123. In this processing, the AF / AE calculation unit performs the focus adjustment and the exposure adjustment based on the RGB signals. The AF / AE calculation unit 126 detects the contrast for each subject distance from the RGB signals for focus adjustment. Based on the detection result, focus adjustment is performed by the focus lens 115. The AF / AE calculation unit extracts a luminance signal from the RGB signal, and detects the field luminance therefrom. Based on this result, exposure adjustment is performed by the iris 113 so that the amount of subject light given to the solid-state imaging device is appropriate.

  The digital camera 100 is basically configured as described above.

  Here, the feature of the present invention in the digital camera 100 resides in the camera shake correction lens 114. Hereinafter, the camera shake correction lens 114 will be described in detail.

  FIG. 4 is a schematic configuration diagram of a camera shake correction lens. Note that subject light enters in the direction of arrow O from the left side of FIG. 4 part (A), the light incident side (left side of FIG. 4 part (A)) is the front side, and the light exit side (part (FIG. 4 part ( The right side of A) is referred to as the rear side, and when the camera shake correction lens 114 in FIG. 4 part (A) is viewed from the front side (left side in FIG. 4 part (A)), the upper side of the camera shake correction lens 114 is viewed. (The upper side of part (A) in FIG. 4) is the upper side, the lower side of camera shake correction lens 114 (the lower side of part (A) in FIG. 4) is the lower side, and the left and right sides of camera shake correction lens 114 (part (A) in FIG. The back / front side of) will be referred to as the left and right sides.

  The camera shake correction lens 114 includes a conductive liquid 302 and an insulating liquid 301 immiscible with the conductive liquid 302 in a liquid container 201 in which both ends of a hollow box 201a are closed with caps 201b and 201c. It is housed and formed. The liquid container 201 is made of transparent glass and corresponds to an example of the liquid container referred to in the present invention.

  The surface (inner surface) in contact with the liquid of the cap 201c that closes the rear end of the box 201a is covered with a hydrophilic film 206 having hydrophilicity. The inner surface of the liquid container 201 other than the portion covered with the hydrophilic film 206 is covered with a hydrophobic film 205 having hydrophobicity.

  Further, the liquid container 201 has a first electrode 202 disposed so as to sandwich the hydrophilic film 206 and in contact with the liquid, an insulating film 204 sandwiched between the box 201a and the hydrophobic film 205, and an insulating film 204. Two second electrodes 203a and 203b that are insulated from the liquid are also provided.

  Part (B) of FIG. 4 is a view of the camera shake correction lens 114 of part (A) as viewed from the front side (left side of part (A)). The two second electrodes 203a and 203b are provided on the upper surface and the lower surface of the box 201a.

  The first electrode 202 and the second electrodes 203a and 203b are connected to the camera shake controller 114a shown in FIG. 3, and the camera shake controller 114a connects the first electrode 202 and the second electrodes 203a and 203b to each other. A voltage is applied between them. The first electrode 202 corresponds to an example of a first electrode according to the present invention, and the second electrodes 203a and 203b correspond to an example of a plurality of second electrodes according to the present invention. The camera shake controller 114a corresponds to an example of a control unit according to the present invention.

  In the liquid container 201 as described above, the insulating liquid 301 and the conductive liquid 302 having different optical refractive indexes are stored. In this embodiment, an organic solvent (Isopar: manufactured by Exxon) is applied as the insulating liquid 301, and a supporting electrolyte (tetrabutylammonium perchlorate 0.1 mol / L) is added to water as the conductive liquid 302. Applies. The insulating liquid 301 corresponds to an example of the insulating liquid referred to in the present invention, and the conductive liquid 302 corresponds to an example of the conductive liquid referred to in the present invention.

  In a state where no voltage is applied between the first electrode 202 and each of the second electrodes 203a and 203b, the conductive liquid 302 repels the water-repellent film 205, so that the insulating liquid 301 and the conductive liquid 302 are repelled. Is a shape as indicated by a solid line in Part (A) of FIG. At this time, the first electrode 202 and the conductive liquid 302 are in contact with each other.

  FIG. 5 is a diagram illustrating a boundary surface between the insulating liquid 301 and the conductive liquid 302 when a voltage is applied to the camera shake correction lens 114 by the camera shake controller 114a.

  When a voltage is applied between the first electrode 202 and the upper second electrode 203a by the camera shake controller 114a, electric charge is discharged from the first electrode 202 to the conductive liquid 302, and the second electrode 203a The charges having the opposite polarity to the charges discharged to the conductive liquid 302 are collected. The electric charge released to the conductive liquid 302 and the electric charge of the second electrode 203a are attracted by Coulomb force, and the electric charge in the conductive liquid 302 is attracted to the vicinity of the upper water-repellent film 205 near the second electrode 203a. . As a result, the boundary surface between the insulating liquid 301 and the conductive liquid 302 changes to a shape in which the insulating liquid 301 is biased downward and the conductive liquid 302 is biased upward, as shown by the solid line in FIG.

  When a voltage is applied between the first electrode 202 and the lower second electrode 203b by the camera shake controller 114a, the electric charge discharged from the first electrode 202 to the conductive liquid 302, and the lower first electrode 202b. The electric charge of the two electrodes 203b is attracted by the Coulomb force, and the boundary surface between the insulating liquid 301 and the conductive liquid 302 is biased upward as shown by the dotted line in FIG. Changes to a downwardly biased shape.

  Moreover, the camera shake controller 114a can not only apply a voltage between the first electrode 202 and one of the upper and lower second electrodes 203a and 203b, but also the first electrode 202 and the second electrode 203a. , 203b can be simultaneously applied with mutually different voltages.

  FIG. 6 is a schematic diagram showing the relationship between the shape of the boundary surface between the insulating liquid 301 and the conductive liquid 302 and the optical path of the subject light passing through the camera shake correction lens 114.

  Here, a camera shake correction lens 114 composed of an insulating liquid 301 having a refractive index n1 and a conductive liquid 302 having a refractive index n2 (n1> n2) is applied, and the distance from the camera shake correction lens 114 in the backward direction is applied. In the following description, it is assumed that the solid-state imaging device 111 is provided at a position separated by D.

  When the angle of the boundary surface between the insulating liquid 301 and the conductive liquid 302 is θ, the subject light that has passed through the optical axis O passes through the insulating liquid 301 and the conductive liquid 302 and then the optical axis O and the solid liquid. An image is formed on the solid-state image sensor 111 at a point P ′ shifted downward by a distance Δ from the intersection P with the image sensor 111. At this time, the following equation holds.

When the refractive index of the insulating liquid 301 is n1, and the refractive index of the conductive liquid 302 is n2,
Δ = D × tan (θout) (1)
n2 × sin (θ2−θ1) = sin (θout) (2)
n1 × sin (θ1) = n2 × sin (θ2) (3)
θ1 = θ (4)
When the applied voltage is controlled by the camera shake controller 114a, the angle θ of the boundary surface between the insulating liquid 301 and the conductive liquid 302 is changed in the vertical direction as shown in FIG. Is changed.

  Here, when the photographer presses the release switch 150 shown in FIG. 1, the digital camera 100 may move. At this time, as the digital camera 100 moves, the course of the subject light passing through the zoom lens 116 and the focus lens 115 shown in FIG. 3 changes, so that the subject light does not pass through the camera shake correction lens 114. If it passes, the imaging position on the solid-state imaging device 111 may be shifted, and there is a possibility that the captured image will be shifted.

  In the digital camera 100 of the present embodiment, the path of the subject light due to the movement of the digital camera is corrected by changing the shape of the boundary surface between the conductive liquid 302 and the insulating liquid 301 of the camera shake correction lens 114. .

  When the photographer presses the release switch 150 shown in FIG. 1, the camera shake controller 114 a acquires the angular velocity in movement of the digital camera 100 from the movement sensor 180.

  Subsequently, the camera shake controller 114a is based on the angular velocity acquired from the movement sensor 180, and the imaging position of the subject light on the solid-state imaging device 111 that shifts with the movement of the digital camera 100 (point P ′ in FIG. 6). ) Is corrected to the correct imaging position (point P in FIG. 6), the angle of the boundary surface between the insulating liquid 301 and the conductive liquid 302 (angle θ in FIG. 6) is calculated, and the boundary is calculated. The applied voltage for realizing the angle of the surface is calculated.

  Further, the camera shake controller 114a applies the calculated voltage between the first electrode 202 and each of the second electrodes 203a and 203b.

  When a voltage is applied between the first electrode 202 and each of the second electrodes 203a and 203b, the angle of the boundary surface between the insulating liquid 301 and the conductive liquid 302 is calculated to an angle calculated by Coulomb force. Adapted.

  The subject light whose optical path has been shifted with the movement of the digital camera 100 passes through the insulating liquid 301 and the conductive liquid 302 of the camera shake correction lens 114, and thus reaches the correct imaging position on the solid-state image sensor 111. The direction is corrected.

  For example, if the refractive index n1 of the insulating liquid 301 is greater than the refractive index n2 of the conductive liquid 302 and the path of subject light is shifted downward due to camera shake or the like, the first electrode is controlled by the camera shake controller 114a. A voltage is applied between 202 and the upper second electrode 203a. As a result, the boundary surface between the insulating liquid 301 and the conductive liquid 302 is adjusted to a shape in which the insulating liquid 301 having a large refractive index is biased upward as indicated by a dotted line in FIG. Is corrected upward.

  Here, since the movement due to camera shake is usually in the vertical direction, as shown in part (B) of FIG. 4, the box 201 a of the liquid container 201 is used to correct the vertical deviation of the subject light in the vertical direction. The example in which the second electrodes 203a and 203b are provided on the upper surface and the lower surface of the lens has been described. However, by disposing three or more second electrodes so as to surround the box 201a, the path deviation of the subject light in the vertical and horizontal directions is corrected. be able to.

  FIG. 7 is a diagram illustrating an example of the arrangement pattern of the second electrodes.

  FIG. 7 is a view of the camera shake correction lens 114 as viewed from the front side (the left side in Part (A) of FIG. 4).

  As shown in part (A-1) of FIG. 7, instead of the box 201 a shown in FIG. 4, a box having a hollow triangular prism is used, and the box is surrounded by three second electrodes 411, thereby providing a digital camera. It is possible to correct the deviation of the course of the subject light due to the movement of 100 in the vertical and horizontal directions. The function similar to that of the camera shake correction lens 410 shown in this part (A-1) is as shown in Part (A-2), in which a camera shake in which a hollow cylindrical box is surrounded by three second electrodes 421. The correction lens 420 is also realized. The electrode arrangements shown in the part (A-1) and the part (A-2) can cope with the subject light path deviation in the vertical and horizontal directions, but the calculation of the applied voltage becomes complicated.

  Further, a camera shake correction lens 430 surrounded by four second electrodes 431 shown in part (B-1) and a cylindrical shape surrounded by four second electrodes 441 shown in part (B-2). The camera shake correction lens 440 makes it easy to calculate the applied voltage and can correct camera shake at high speed.

  Further, as shown in Part (C-1) and Part (C-2), camera shake correction lenses 450 and 460 using eight second electrodes 451 and 461 correct camera shake with higher accuracy. be able to.

  Above, description of 1st Embodiment of this invention is complete | finished and 2nd Embodiment of this invention is described. Since the first embodiment and the second embodiment have the same apparatus configuration except for the camera shake correction lens 114, the difference from the first embodiment is noted, and the same elements are denoted by the same reference numerals and described. Omitted.

  FIG. 8 is a simplified configuration diagram of a camera shake correction lens to which the second embodiment of the present invention is applied.

  The camera shake correction lens 500 of the present embodiment has substantially the same configuration as the camera shake correction lens 114 of the first embodiment shown in FIG. 4, and two lens elements 510 provided with second electrodes at different positions. , 520. The lens elements 510 and 520 correspond to an example of the lens element referred to in the present invention.

  The lens element 510 shown on the left side of FIG. 8 has the same configuration as the camera shake correction lens 114 of the first embodiment shown in FIG. 4, and the second electrode 203 a is placed above and below the box 201 a of the liquid container 201. Has been deployed. When a voltage is applied to the lens element 510, the boundary surface between the insulating liquid 301 and the conductive liquid 302 of the lens element 510 is deformed in the vertical direction.

  Further, in the lens element 520 shown on the right side of FIG. 8, the second electrode 203 a is arranged on the left and right of the box 201 a of the liquid container 201. When a voltage is applied to the lens element 520, the boundary surface between the insulating liquid 301 and the conductive liquid 302 of the lens element 520 is deformed in the left-right direction.

  According to the camera shake correction lens 500, the object light passing through the camera shake correction lens 500 is controlled by the voltages applied to the lens element 510 and the lens element 520, respectively. The course is adjusted in the vertical direction, and when passing through the lens element 520, the course is adjusted in the horizontal direction. Therefore, according to the camera shake correction lens 500, the camera shake correction lenses 430 and 440 provided with the four second electrodes 431 and 441 shown in part (B-1) and part (B-2) of FIG. Almost the same operation can be realized with a simple configuration.

  Here, in the above description, an example in which two kinds of liquids, that is, a conductive liquid and an insulating liquid are accommodated in the liquid container has been described. However, the liquid container referred to in the present invention has three or more kinds of liquids. It may be accommodated.

  In the above description, an example in which the lens unit of the present invention is applied to preventing camera shake has been described. However, the lens unit of the present invention may be applied to a focus lens, a zoom lens, or the like. For example, when the lens unit of the present invention is applied to a focus lens, a voltage for realizing a TTLAF function and a voltage for realizing a camera shake correction function between a first electrode and a second electrode. These functions can be realized with a single lens.

  In the above description, the example of the movement sensor that detects the azimuth angular velocity and the elevation angular velocity has been described. However, the sensor referred to in the present invention is, for example, one that detects a movement amount within a predetermined time for each direction. Also good.

  Subsequently, various forms that can be adopted in each component constituting the present invention will be additionally described.

  The conductive liquid and the insulating liquid referred to in the present invention may be two or more kinds of liquids having different refractive indexes and not mixed with each other. The difference in specific gravity between these liquids is preferably 0.1 or less.

  Any combination of these liquids may be used, but a combination of water and an organic solvent is preferable. As the organic solvent, preferably, hydrocarbons (hexane, heptane, pentane, octane, isopar (exxon), etc.), hydrocarbon aromatic compounds (benzene, toluene, xylene, mesitylene, etc.), halogenated hydrocarbons ( Difluoropropane, dichloroethane, chloroethane, bromoethane, etc.), halogenated hydrocarbon aromatic compounds (chlorobenzene, etc.), and ether compounds (diphenyl ether, anisole, diphenyl ether, etc.) are preferred. More preferred are tetralin and diffnon.

  Moreover, it is preferable to add a supporting electrolyte to water for the purpose of increasing electrical conductivity. As the supporting electrolyte, TMAP: Tetramethylammonium perchlorate, TBAF: Tetrabutylammonium hexafluorophosphate, or the like is used.

  Here, the basic embodiment for realizing the concept of the present invention has been described above. However, when the lens unit employed in the present invention is put into practical use, dust, water droplets, or the like adhere to the optical path. It is preferable to devise measures to prevent a problem that the lens performance deteriorates.

  For example, it is preferable to provide a water-repellent film on the outer surface (hereinafter, this surface is referred to as a light transmission surface) that intersects with the optical path of the container containing the liquid. By imparting water repellency to the light transmitting surface, dust and water droplets are prevented from adhering and the high light transmittance of the lens unit can be maintained. The material constituting the water-repellent film is preferably a silicone resin, an organopolysiloxane block copolymer, a fluorine-based polymer, or polytetrafluoroethane.

  It is also preferable to attach a hydrophilic film to the light transmission surface of the container constituting the lens unit. By imparting hydrophilic oil repellency to the light transmitting surface, it is possible to prevent dust from adhering. As this hydrophilic film, a film composed of an acrylate polymer, or a film coated with a surfactant such as a nonionic organosilicone surfactant is preferable. Monomer plasma polymerization, ion beam treatment, and the like can be applied.

  It is also preferable to attach a photocatalyst such as titanium oxide to the light transmitting surface of the container constituting the lens unit. Dirt is decomposed by the photocatalyst that reacts with light, and the light transmission surface can be kept clean.

  It is also preferable to provide an antistatic film on the light transmission surface of the container constituting the lens unit. If static electricity accumulates on the light transmission surface of the container or is charged by an electrode, dust or dust may stick to the light transmission surface. By attaching an antistatic film to the light transmission surface, it is possible to prevent such unnecessary objects from being attached and maintain the light transmittance of the lens unit. The antistatic film is preferably composed of a polymer alloy material, and the polymer alloy system may be a polyether type, a polyether ester amide type, those having a cationic group, Name, Daiichi Kogyo Seiyaku Co., Ltd.). The antistatic film is preferably produced by a mist method.

  Further, an antifouling material may be applied to the container constituting the lens unit. As the antifouling material, a fluororesin is preferable, but specifically, a fluorine-containing alkylalkoxysilane compound, a fluorine-containing alkyl group-containing polymer, an oligomer, or the like is preferable, and has a functional group capable of crosslinking with the curable resin. Is particularly preferred. Moreover, it is preferable that the addition amount of antifouling | stain-proof material is a required minimum amount which expresses antifouling property.

It is a schematic block diagram of the liquid lens which is a comparative example. It is the external appearance perspective view which looked at the digital camera with which one Embodiment of this invention was applied from front diagonally upward. It is a schematic block diagram of the digital camera shown in FIG. It is a schematic block diagram of a camera-shake correction lens. It is a figure which shows the interface between the insulating liquid 301 and the conductive liquid 302 when a voltage is applied to the camera shake correction lens 114 by the camera shake controller 114a. 6 is a schematic diagram showing a relationship between an angle of a boundary surface between an insulating liquid 301 and a conductive liquid 302 and an optical path of subject light passing through a camera shake correction lens 114. FIG. It is a figure which shows the example of the arrangement pattern of a 2nd electrode. It is a simple block diagram of the camera-shake correction lens to which the second embodiment of the present invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid lens 11 Container 11a Tube 11b, 11c Cap 12 1st electrode 13 2nd electrode 14 Insulating film 15 Water repellent film 16 Hydrophilic film 21 Oil 22 Water 100 Digital camera 101 Shooting lens 102 Optical viewfinder objective window 103 Auxiliary light emission Unit 104 power switch 110 imaging optical system 111 solid-state imaging device 112 shutter 112a shutter motor 113 iris 113a iris motor 114 camera shake correction lens 114a camera shake controller 115 focus lens 115a focus motor 116 zoom lens 116a zoom motor 120 signal processing unit 120a analog processing (A / D) section 120b digital signal processing section 120c motor driver 121 system controller 122 image signal processing section 123 image display Control unit 124 Image compression unit 125 Media controller 126 AF / AE calculation unit 127 Key controller 128 Buffer memory 129 Internal memory 1200 Bus 130 Image display unit 140 External recording medium 150 Release switch 160 Shooting mode switch 170 Zoom switch 180 Movement sensor 201 Liquid storage Container 201a Tube 201b, 201c Cap 202 First electrode 203 Second electrode 204 Insulating film 205 Water repellent film 206 Hydrophilic film 301 Insulating liquid 302 Conductive liquid

Claims (6)

A liquid container that transmits light at least in a predetermined optical axis direction, in which an insulating liquid and a conductive liquid that are different in refractive index from each other and immiscible with each other and each have optical transparency, are accommodated inside. When,
A first electrode in contact with the conductive liquid in the liquid container;
A plurality of second electrodes insulated from the conductive liquid in the liquid container;
A sensor for detecting movement of the liquid container in a predetermined direction;
A voltage corresponding to a detection result by the sensor is applied between the first electrode and each of the plurality of second electrodes to change the shape of the boundary surface between the insulating liquid and the conductive liquid. And a control unit that suppresses a change in the path of light transmitted through the liquid container as the liquid container moves.   The lens unit according to claim 1, wherein the conductive liquid is water and the insulating liquid is an organic solvent.   The lens unit according to claim 2, wherein the insulating liquid is a hydrocarbon-based organic solvent.   2. The lens unit according to claim 1, wherein the plurality of second electrodes include three or more electrodes surrounding an optical path of light passing through the liquid container. A plurality of lens elements arranged in the optical axis direction, each having the liquid container, the first electrode, and the second electrode, the arrangement of the second electrodes being different from each other;
The sensor detects movement of the entire plurality of lens elements;
The control unit applies each voltage according to the detection result of the sensor to each of the plurality of lens elements, so that the light passes through the plurality of lens elements as the plurality of lens elements move. A lens unit that suppresses changes. A liquid container that transmits light at least in a predetermined optical axis direction, in which an insulating liquid and a conductive liquid that are different in refractive index from each other and immiscible with each other and each have optical transparency, are accommodated inside. A photographing optical system having a first electrode in contact with the conductive liquid in the liquid container, and a plurality of second electrodes insulated from the conductive liquid in the liquid container;
An imaging element that forms an image signal representing the subject light by imaging subject light that has passed through the photographing optical system;
A sensor for detecting movement of the liquid container in a predetermined direction;
A voltage corresponding to a detection result by the sensor is applied between the first electrode and each of the plurality of second electrodes to change the shape of the boundary surface between the insulating liquid and the conductive liquid. An image pickup apparatus comprising: a control unit that suppresses a shift in an image formation position on the image pickup element of subject light that has passed through the photographing optical system due to movement of the photographing optical system .

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