Liquid lens

<img file="NL1033503C2_D0001.tif" />

Patent Center

Netherlands © 1033503 © C PATENT²⁰ © Application number: 1033503 © Submitted: 06.03.2007 © Int.CI .:

G02B3 / 14 (2006.01)

<td>© Priority:</td><td>© Patent holder (s):</td>

<td>08.03.2006 KR 10-2006-0021646</td><td>Samsung Electro-Mechanics Co., Ltd. to</td>

<td></td><td>Gyunggi, Republic of Korea (KR).</td>

<td>© Registered:</td><td></td>

<td> 11.09.2007</td><td>© Inventors):</td>

<td></td><td>Sung Chan Kim in Seoul (KR).</td>

<td>© Granted:</td><td>Ha Yong Jung at Gyeonggi (KR).</td>

<td> 24.06.2009</td><td>Jin Hyuck Yang in Gyeonggi (KR).</td>

<td></td><td>Young Ho Lee in Gyeonggi (KR).</td>

<td>© Published:</td><td></td>

<td> 01.09.2009</td><td>© Authorized representative:</td>

<td></td><td>Drs. MJ Hatzmann et al. At 2508 DH</td>

<td></td><td>The Hague.</td>

O Liquid lens.

A liquid lens comprising a cylindrical body comprising a pair of glass lenses successively coupled to the upper and lower openings of the body; an aspherical transmitting separation lens, mounted and attached in the central part of the body; an autofocus lens section composed of a first insulating liquid layer and a first conductive liquid layer, which are inserted below the transmitting separation lens to form an interface therebetween; an optical zoom lens section composed of a second insulating liquid layer and a second conductive liquid layer inserted above the transmitting separation lens such that an interface is formed therebetween; and a precision autofocus lens section composed of a third insulating liquid layer the upper interface of which contacts the lower surface of the transmitting separation lens and the lower surface of which interfaces with the first conductive liquid layer so that the third insulating liquid layer is not mixed with the first conductive layer .

NL C1033503

This patent has been granted regardless of the enclosed result of the prior art research and written opinion. The patent corresponds to the documents originally filed.

The Netherlands Patent Center is an agency of the Ministry of Economic Affairs.

TiteL Liquid lens

Cross References to Related Applications This application claims the right of priority over Korean Patent Application No. 10-2006-0021646 filed with the Korean Intellectual Property Office on March 8, 2006, the disclosure of which is incorporated herein by reference.

Background of the invention

1. Field of the Invention The present invention relates to a liquid lens for mounting on mobile phones. In the liquid lens, conductive and insulating liquids, the curvatures of which can be varied by applying a tension, are arranged in a cylindrical body so that they form a number of interfaces in the upper and lower parts thereof, with respect to a transparent separating lens . In this situation, if an amount of an electric charge is supplied to the conductive liquid by electrodes connected to the conductive liquid, an optical zoom function, an autofocus function and a precision autofocus function can be performed simultaneously.

2. Description of the Prior Art Recently, because new types of mobile terminals such as mobile phones or personal digital assistants (PDA) have been introduced in

335 03 are increasingly marketed, an increasing need for mobile terminals with an integrated camera with many pixels and various functions arises. Such a mobile terminal camera includes a lens attached to an image pick-up device such as, for example, a charge coupled device (CCD), complementary metal oxide semiconductor (CMOS) and the like, and is configured to capture an image of a subject through the lens. and save the data of the recorded image by means of a predetermined storage medium.

In order to provide for cameras with the ability to function at a mega-pixel level according to the current trend, the lens must be designed so that it not only has sufficient resolving power but is larger in size than that of the composition tolerance. of the sensors.

A lens system, which is mounted on the mobile terminal to capture an image of a subject, is generally sensitive to various anomalies, such as spherical anomalies, astigmatism, warp anomaly, etc., that distort the appearance or morphology of the subject's image due to the influence of the incident light of various wavelengths incident on the lens when the subject's image is captured. It is therefore necessary to take measures to suppress these deviations as much as possible.

Such a lens system can realize a zoom in order to have a variable focus distance. In general, a zoom function of the lens can be achieved by adjusting the distance between the lenses by relative displacement of a front lens with a positive refractive index relative to a rear lens with a negative refractive index. To maximize zoom in a general purpose camera, an additional wide-angle or telephoto lens is fitted to the camera, capable of changing the focus distance between the existing lens and an additional lens, allowing the user to take pictures from different angles from one place without having to move.

The zoom is generally divided into an optical zoom and a digital zoom. The optical zoom refers to a situation where the image of the subject is enlarged by varying the focus distance by the relative movement of an optical lens mounted on the camera. The digital magnification refers to a situation where the image of the subject is enlarged in the CCD and displayed therein, such as enlarging an image in a graphics program such as Photo-Shop and the like.

In the digital zoom, the image of the subject in the CCD is enlarged, eliminating the need to move the lenses to adjust the focus distance. The digital zoom is therefore advantageous in terms of miniaturization and compactness, but disadvantageous in that high image resolution cannot be achieved during image recording by means of this magnification.

On the other hand, in the optical zoom, the magnification is realized by the variation in the focus distance between the lenses, thus taking up space for the movement of the lenses, according to the changing of the focus distance. The optical enlargement is thus disadvantageous because a lot of space is taken up by a lens part and by a lens holder which comprises the lens part. Despite the disadvantages of increasing the volume of the mobile terminal, the consumer may still prefer it over the digital zoom, because of its better properties with regard to a larger resolution when zooming in.

Nevertheless, a recent trend of miniaturization and compactness in the market requires a decrease in the space required to change the focus distance, and therefore the producers have mainly marketed mobile phones that have a digital zoom function rather than an optical zoom function. . In recent years, a type of mobile terminals with optical magnification have also been introduced, whereby the optical zoom function can be performed through the back of the phone.

Korean Patent Application No. 2003-0003984 discloses a conventional mobile terminal which may be equipped with an optical zoom. The disclosure mobile terminal has an improved lens holder structure for an optical zoom applicable to digital cameras and the like. In other words, disclosed are a lens holder structure of a zoom camera, which is small in size, high in resolving power and easy to manufacture, and a zoom lens assembly with the lens holder structure.

The zoom lens assembly includes a front lens, a rear lens with a negative refractive index, an inner lens holder which has a spiral groove formed along the surface of the inner lens holder which serves to guide the front and rear lenses in a spiral movement and an outer lens holder which can be slid along the surface of the inner lens holder and which has an escape groove on the inner surface of the outer lens holder to guide the front and rear lenses in a vertical movement.

[0013] In the zoom camera constructed as described above, the inner and outer lens holders are telescoped on one side of the mobile terminal so that the focus distance of the zoom camera can vary due to the relative movement between the lenses due to the inner and the outer containers are successively slid apart by a drive motor in the terminal, whereby an optical zoom is absorbed. As a result, the zoom camera from the disclosure has the disadvantage that a large space is required for the zoom operation inside the camera.

In addition, the loss of power of the motor during the inevitable displacement of the inner and outer container containing a plurality of lenses to the outer of the camera by the motor of the camera causes an increase in the energy consumption of a battery.

In order to solve the above-mentioned problems, a liquid lens has been developed, which occupies only a small space in a mobile terminal and does not have energy consumption. The liquid lens includes a conductive liquid and an insulating liquid in a single lens holder interposed, whose curvature can be changed by applying tension to the conductive liquid through the lens holder to effect the zoom function.

One of the liquid lenses capable of effecting a zoom function is disclosed in Korean Laid-Open Disclosure No. 20050033308 entitled Zoom camera using the liquid lens for mobile phone, control system thereof and method thereof, which will be described below. with reference to figure 1.

Figure 1 is a cross-sectional view of a conventional liquid lens. Figure 1 shows the conventional liquid lens comprising a first group of lenses 310 comprising a first lens 311 with a positive refractive index and a second lens 312 with a negative refractive index, a first liquid lens 300 comprising an interface formed between a conductive and an insulating liquid wherein the curvature of the interface can be varied in response to a control signal for a zoom function, a second group of lenses 330 comprising a third lens 331, both surfaces of which are aspherical and having a positive refractive index, and a fourth lens 332, of which both surfaces are aspherical with a negative refractive index and an infrared filter 340 spaced at a predetermined distance from the second group of lenses 330 is provided.

The conventional disclosure liquid lenses are driven on the basis of an electrowetting phenomenon, as shown in Figure 2, in which the electrowetting phenomenon is caused by a variation of the contact angle α due to changing the surface tension of an interface by the movement of charges that are present at the interface. More specifically, a thin dielectric member is placed on the interface to provide a high potential difference across the surface, whereby the charges in the conductive liquid tend to move toward a higher plane of the interface due to its chemical properties.

As an electric field is applied to the interface from the outside, the tendency of the charges to intensify further and the concentration of charges on a contact line where the three interfaces meet to increase significantly, causing the repulsive forces between the loads increase. This reduces the surface tension at the contact angle of a liquid droplet.

Since the electrowetting phenomenon can be used to easily control a small amount of a liquid and fine particles in the liquid, several studies have been conducted in recent years into the application of the electrowetting phenomenon in a variety of products, for example in liquid lenses, micropumps, display devices, optical devices, micro electromechanical systems (MEMS), etc.

In particular, an autofocus liquid lens has better properties with regard to smaller size, lower power consumption and faster responsive times compared to conventional mechanically driven lens types.

The liquid lens constructed as described above may include an enlargement function due to the variation in curvature of the interface between the conductive liquid and the insulating liquid of the separate liquid lens within a single lens holder in which the multiple lens groups and the liquid lens are arranged , which solves the problem of the spatial limitation of the conventional optical magnification required by the telescopic zoom lens, is resolved.

However, regardless of these advantages, the conventional liquid lens has the problem that a single liquid lens allows a zoom function only due to the variation in the curvature of the interface between the liquids held together in the lens holder.

In addition, conventional liquid lenses have the problem of complicating the composition of the camera. The structure of the camera is mainly complicated if the camera with the liquid lens is used for other functions, for example for an autofocus (A / F) adjustment function as well as for a zoom function, where an added lens must be attached to the camera to act as a front lens serves.

In addition, the insulating liquids and the conductive liquids that form a plurality of interfaces are inevitably sensitive to external impact and shaking due to the properties of the liquid lens. Therefore, the autofocus function for adjusting the focus on an object is not performed in a desired manner, although the optical magnification function and the autofocus (A / F) adjustment setting as well as the zoom function can be arranged in an intricate structure.

Summary of the Invention An advantage of the present invention is that it provides a liquid lens. In the liquid lens, conductive and insulating liquids, the curvatures of which of the interfaces are varied by the application of a tension, are arranged in a cylindrical body, whereby a plurality of interfaces in the upper and lower parts thereof are compared with a transparent separating lens formed. In this state, when the curvatures of the interfaces between the conductive and insulating liquids can be successively varied by applying a voltage, an amount of electric charge is adjusted. Then, an optical zoom function, an autofocus function and a precision autofocus function can be performed simultaneously.

Further aspects and advantages of the present general inventive concept will be explained in the following part of the description, and in part will be obvious from this description or may be obsolete by carrying out the general inventive concept.

In one aspect of the invention, a liquid lens comprises a cylindrical body, comprising a pair of glass lenses coupled to higher and lower openings of the body, respectively; an aspherical transparent separation lens, which is mounted and secured in a central part of the body; an autofocus lens section composed of a first insulating liquid layer and a first conductive liquid layer disposed under the transparent separating lens to form an interface therebetween; an optical zoom lens section composed of a second insulating liquid layer and a second conductive liquid layer disposed above the transparent separating lens to form an interface therebetween; and a precision autofocus lens portion composed of a third insulating liquid layer the upper surface of which contacts the lower surface of the transparent separating lens and the lower surface of which interfaces with the first conductive liquid layer so that the third insulating liquid layer is not mixed with the first conductive liquid layer. low.

According to another aspect of the invention, the body has an inner peripheral surface formed of a metal-coated surface using gold (AU).

In a further aspect of the invention, the aspherical separating lens has a lower surface, the peripheral portion of which is formed as a sloping surface, the angle of inclination of which is an obtuse angle of more than 90 °.

According to a further aspect of the invention, the separation lens is made of a transparent material.

According to a further aspect of the invention, a hydrophobic film layer or an insulating film layer is applied to the separation lens.

According to a further aspect of the invention, the liquids in the first insulating liquid layer, the first conductive liquid layer and the third insulating liquid layer arranged in layers below the separating lens, the same characteristic relative to the separation lens and the liquids of the second insulating liquid layer and the second conductive liquid layer layered above the separation lens have the same characteristic.

According to yet a further aspect of the invention, the liquids above and below the separation lens have different characteristics and properties relative to each other.

Following yet a further aspect of the invention, the third insulating liquid layer is deformed by the changes in the curvature of the top surface of the first conductive liquid layer to which a stress is applied by means of an applied to the inner metal-coated peripheral surface of the body and forming film coating thereon.

Brief Figure Description These and / or other aspects and advantages of the present general inventive concept will become apparent and may be more readily understood from the following description of the embodiments, in conjunction with the accompanying drawings, in which:

[0036] FIG. 1 is a sectional view of a conventional liquid lens;

[0037] FIG. 2 is a schematic representation showing the typical electrowetting effect applied to a liquid lens;

[0038] FIG. 3 is a sectional view of a liquid lens according to the present invention;

[0039] FIG. 4 is an enlarged sectional view showing part of one side of the liquid lens of the present invention;

[0040] FIG. 5 is a perspective view showing the rear surface of an aspherical transparent separating lens mounted on the liquid lens of the invention; and FIG. 6A to 6D are sectional views showing the operation of the liquid lens of the present invention.

Detailed description of the preferred embodiments.

Reference is now made in detail to the embodiments of the present general inventive concept, the examples of which are illustrated with drawings, in which like numerals throughout the text refer to like parts. The embodiments are described below with reference to the figures to illustrate the current general inventive concept.

Hereinafter, a liquid lens according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Structure of the Lens FIG. 3 is a sectional view of the liquid lens of the invention. Fig. 4 is an enlarged sectional view showing part of one side of the liquid lens of the present invention; Fig. 5 is a perspective view showing the rear surface of an aspherical transparent separation lens mounted in the liquid lens of the invention.

As shown in the drawings, the liquid lens 10 includes a cylindrical body 11, a pair of glass lenses 12 and 13, an autofocus lens section 20, an optical zoom lens section 30, and a precision autofocus lens section 41. The successive glass lenses 12 and 13 are mounted and attached on the top and bottom openings of the cylindrical body 11. On the inside of the body 11, a plurality of conductive fluid layers 22 and 23 and a plurality of insulating layers 21, 31, and 41 are layered to form multiple interfaces, the conductive fluid layers 22 and 32, and the insulating fluid layers 21,31 , and 41 have different properties from each other. The liquid lens 10 is divided into an upper and a lower part by a transparent separating lens 23.

The body 11 consists of metal or ceramic material. The lower surface of the body 11 consists of an inclined surface 14 which is inclined downwards towards the central part thereof. The pair of glass lenses 12 and 13 are attached and bonded to the top and bottom end surfaces of the body 11 with an adhesive B, thereby closing the top and bottom openings of the body.

The inclined surface 14 of the body 11 serves to hold a first insulating layer 21 in place in the central portion of the body 11, the first insulating layer 21 being in the lowest portion. The inclined plane 14 is shaped so that the overall size of the autofocus lens section 20 is reduced when the interface between them is bent according to the applied voltage.

In the lower portion of the body 11, a first insulating liquid layer 21 and a first conductive liquid layer 22 are layered so that they form an interface, the first insulating liquid layer 21 and the first conductive layer 22 having different properties and are formed from transparent liquids that have the same density but are immiscible. A third insulating liquid layer 41 is then layered on the first conductive liquid layer 22 so that it forms a different interface.

On the third insulating layer 41, the transparent separating lens 23 having an aspherical surface is placed such that the upper surfaces of the first conductive liquid layer 22 and the third insulating liquid layer 41 simultaneously come into contact with the transparent separating lens 23. Under the separating lens 23 the autofocus lens section is provided, comprising the third insulating layer 41 serving as a precision autofocus lens section.

In the autofocus lens section 20, the curvature of the interface between the first conductive liquid layer 22 composed of a conductive liquid and the first insulating liquid layer 21 is varied when a voltage is applied to the first conductive layer 22. As a result, the first insulating liquid layer becomes convex upwardly so that an autofocus function (A / F) is performed.

The curvature of the top portion of the first conductive liquid layer 22 is varied in that an amount of electric charge is increased or decreased by varying the voltage applied to a first conductive liquid layer 22. Thereafter, the third conductive liquid layer 41 becomes convex downwardly simultaneously or sequentially after the first insulating liquid layer 21, so that a precision autofocus function (A / F) is performed.

Functional differences between the autofocus function and the precision autofocus function and their operation will be described by reference to the operational structure of the liquid lens.

The separation lens 23 mounted on the autofocus lens section 20 and on the third insulating liquid layer 41 is formed with an aspherical surface the top surface of which is convex and the bottom surface is concave. The separation lens 23 is formed from a transparent lens such as a plastic lens or a glass lens which is transparent. The peripheral surface of the separating lens 23 is closely connected to the central portion of the inner peripheral surface of the body 11. Furthermore, the separating lens 23 serves to divide the liquid lens 10 into an autofocus lens section 20, comprising the third conductive liquid layer 41, the first conductive liquid layer 22. and the first insulating liquid layer 21 and the optical zoom lens 30 comprising the second conductive liquid layer 32 and the second insulating liquid layer 31.

The aspherical transparent separation lens 23 includes a recess 24 formed at a preset depth in the central portion of the bottom surface of the lens. In the peripheral part of the recess 24, an inclined plane 24a with an obtuse angle of more than 90 ° is provided. In such a structure with an inclined surface 24a, the conductive liquid layer 41 is injected into the recess 24 and is formed to be smaller in size than the insulating liquid layer above the separating lens 23. The third conductive liquid layer 41 is passed through the inclined surface 24a concentrated in the central area.

On the surface of the separation lens 23, a hydrophobic film is applied so that the higher and lower insulating liquids are absorbed on the surface of the separation lens 23. Thereby, the respective insulating liquids are fixed in the central part of the separation lens so that stable operation is guaranteed.

In addition, an insulating film coating may be applied to the separating lens 23, said insulating film coating being composed of the same material as that which in some cases is applied to the inner peripheral surface of the body 11.

A second insulating liquid layer 31 and a second conductive liquid layer 32 are layered in the optical zoom lens section 30 on the autofocus portion 20 to form an interface therebetween, the second insulating liquid layer 31 and the second conductive liquid layer 32 liquids with the same properties exist. When a voltage is applied to the second conductive liquid layer 32, the interface between the second insulating liquid layer 31 and the second conductive liquid layer 32 is bent. In that case, the second conductive liquid layer 31 becomes convex upwardly so that an optical zoom function is performed.

The successive insulating liquids and the successive conductive liquids, which are layered so that they form a plurality of interfaces in the autofocus lens portion 20 and the optical zoom portion 30, have different properties from one another. The conductive liquids mainly consist of water (H2O), to which inorganic salts and polar solvents have been added. The insulating liquids mainly consist of silicone oil to which non-polar solvents have been added. When the conductive liquid and the insulating liquid come into contact with each other, they do not mix with each other but form an interface with a predetermined curvature.

The liquids that form the first and second conductive liquid layers 22 and 31 contain the same components but differ in composition so that their properties are different from each other. Accordingly, the insulating liquid of the first insulating liquid layer 21 comprises the same components as the second insulating liquid layer 31, but has a different property from that of the second insulating liquid layer 31.

The liquids of the first insulating liquid layer 21, the first conductive liquid layer 22 and the third conductive liquid layer 41, which are layered under the separating lens 23, have the same characteristic with respect to the separating lens 23 and the liquids of the second insulating liquid layer 31 and the second conductive liquid layer

32 which are layered above the separation lens 23 have the same characteristic. In another case, the liquids above and below the separation lens 23 are insulating liquids and conductive liquids with different characteristics from each other.

As shown in Figure 4, the body 11 forming the liquid lens 10 has an inner peripheral surface with a metal coated surface 15 thereon which can serve as an electrode. The coated surface 15 is formed by a surface coating method using gold (Au). Gold hardly reacts when it comes into contact with various liquids.

An insulating film coating 16 is applied to the metal-coated surface 15 so that it serves as an insulating film, thereby forming insulating interfaces that come into contact with the plurality of liquids. Extending film coatings 17a and 17b are formed on the interfaces of the peripheral parts of respective conductive liquid layers 22 and 32 so that a stress can be applied to the conductive liquids 22 and 32, respectively. An electrical signal applied to the body 11 is applied to the conductive liquid layers through the film coatings 17a and 17b which communicate with the conductive liquid layers 22 and 33, respectively.

Lens Operation Figures 6A and 6D are sectional views showing operation of the lens of the present invention. Figure 6A shows an initial stage before a voltage is applied. Figure 6B shows a stage in which a voltage is applied to the autofocus portion of the lens. Figure 6C shows a stage at which a voltage is applied to the optical zoom lens section and to the autofocus lens section simultaneously. Figure 6D shows a stage in which a voltage is applied to the autofocus lens section, the optical zoom lens section, and the precision autofocus lens section simultaneously.

At the initial stage, in which no voltage is applied as shown in Fig. 6A, the first insulating liquid layer 21 and the third insulating liquid layer 41 of the autofocus lens section 20 and the second conductive liquid layer 31 of the optical zoom lens section have the smallest thickness in succession. At this time, the first conductive liquid layer 22 forms an interface with the insulating liquid layers 21 and 41, respectively, so that it has a preset curvature. Furthermore, the second conductive liquid layer 32 forms an interface with the insulating liquid layer 31, so that a preset curvature is created.

When a tension is applied to the autofocus lens section 20 of the body 11 to effect an autofocus adjustment, the tension is applied through the metal-coated surface 15 of the inner peripheral surface of the body 11 to the peripheral portion of the first conductive liquid layer 22. fitted. Thereby, the first conductive liquid layer 22 is driven such that the curvature of the interface between them can be adjusted, as shown in Figure 6B. Furthermore, the first insulating liquid layer 21 is curved upward convexly according to the displacement of the changed curvature of the first conductive liquid layer 22. Thus, the autofocus section 20 of the lens is driven.

Figure 6C is a cross-sectional view of the optical zoom section of the liquid lens when actuated. When a voltage is applied to the body 11, the tension is applied through the metal-coated surface 15 of the body 11 on the top film coating 17a to the peripheral portion of the second conductive liquid layer 32 so that the optical zoom lens section 30 is driven. Then, the second conductive liquid layer 32 layered on the transparent separating lens 23 is controlled so that the curvature of the interface with the second insulating layer 31 is varied. The upper part of the second insulating liquid layer 31 is bent convexly in accordance with the displacement of the interface. Thus, the optical zoom lens portion 30 is driven.

The displacement of curvature of the second conductive liquid layer 32 is adjusted by the change in the amount of charge applied to the second conductive liquid layer 32. Accordingly, an optical zoom magnification is determined, which is in accordance with the thickness of the second insulating liquid layer 31, which is varied accordingly.

Figure 6D shows a stage where the autofocus lens section and the optical zoom lens section of the body 11 are driven simultaneously. At this stage, the curvature of the third conductive liquid layer 41, which is layered on the first conductive liquid layer 22, is varied in accordance with a change of charge applied on the first conductive liquid layer 22, so that a precision auto focus function is performed. When a voltage is simultaneously applied to the upper and lower metal film coatings 17a and 17b through the metal coated surface 15 of the inner peripheral surface of the body 11, the first and second conductive liquid layers are driven simultaneously. Then, by varying the curvatures of the insulating liquid layers 21 and 31 that interface with the respective conductive liquid layers 22 and 32, the optical zoom function and the autofocus function are performed simultaneously.

Thus, when the body moves by an external shock to it at the stage of Figure 6C where the optical zoom is performed or at the stage of Figure 6B where the optical zoom is not performed, when an object moves minimally in a stage where the autofocus function is performed so that the focus is determined, or when minute focus point adjustments by a macro lens (close to lens) are required, a tension is applied to the film coating 17b extending to the top surface of the first conductive liquid layer 22 so that the curvature of the upper interface of the first conductive liquid layer 22 is varied. When the third insulating liquid layer 41 on the first conductive liquid layer 22 becomes convex downward, precision autofocus adjustment is performed.

The application of voltage for the precision autofocus adjustment can be performed automatically after the first insulating liquid layer 21 is actuated to perform the autofocus function. In some cases, this application of tension by means of the film coating 17b can only be performed by manual operation.

The liquid lens of the invention having a structure 5 similar to that described above is composed of an autofocus lens section 20 and an optical zoom lens section 30. Furthermore, the liquid lens has an aspherical transparent separating lens 23 arranged such that the liquid lens is divided into an autofocus lens section 20. and an optical zoom lens section 30. The conductive liquid layers 22 and 32 and the insulating liquid layers 21 and 31 are bent at a preset radius of curvature by stresses applied to the respective lens sections 20 and 30. Furthermore, the third insulating liquid layer 41 under the separating lens 23 is simultaneously or successively a change in the amount of electrical charge driven. Then, the autofocus function including a precision autofocus function and the optical zoom function are simultaneously performed in the respective lens sections 20 and 30 of the single liquid lens.

In the liquid lens of the present invention, when the magnitude of the voltage applied to the first conductive liquid layer is set or a separate voltage is applied to the metal film coating, the third conductive liquid layer is driven to perform the autofocus function. At this time, the precision autofocus function is performed simultaneously or sequentially.

Therefore, the adjustment of the precision autofocus function relative to the object can be performed. Furthermore, if an immediate autofocus response is performed on moving an object or moving the lens, it is possible to obtain a sharp image at any time.

Although a few embodiments of the present inventive concept have been shown and described, those skilled in the art are aware that changes can be made to these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is to attached claims and their equivalents is defined.