阅读说明：本技术 透镜曲率改变装置 (Lens curvature changing device ) 是由 宋昇昕 梁诚午 于 2018-07-20 设计创作，主要内容包括：本发明涉及透镜曲率改变装置。根据实施方式的透镜曲率改变装置是一种用于基于施加的电信号来改变具有可变曲率的液体透镜的曲率的透镜曲率改变装置,该透镜曲率改变装置包括：以及控制单元,用于根据所感测的曲率控制透镜驱动单元形成液体透镜的目标曲率。传感器单元感测液体透镜中的在电极上的绝缘体与导电水溶液之间的边界区域的面积或大小的变化。因此,可以快速且准确地感测透镜的曲率。(The present invention relates to a lens curvature changing device. A lens curvature changing device according to an embodiment is a lens curvature changing device for changing a curvature of a liquid lens having a variable curvature based on an applied electric signal, the lens curvature changing device including: and a control unit for controlling the lens driving unit to form a target curvature of the liquid lens according to the sensed curvature. The sensor unit senses a change in area or size of a boundary region between an insulator on the electrode and the conductive aqueous solution in the liquid lens. Therefore, the curvature of the lens can be sensed quickly and accurately.)

1. A lens curvature changing device for changing a curvature of a liquid lens based on an applied electric signal, the lens curvature changing device comprising:

a lens driver for applying the electrical signal to the liquid lens;

a sensor unit for sensing a curvature of the liquid lens formed based on the electrical signal; and

a controller for controlling the lens driver based on the sensed curvature to form a target curvature of the liquid lens,

wherein the sensor unit senses a size of an area of a boundary region between an insulator on an electrode and a conductive aqueous solution in the liquid lens or a change in the size.

2. The lens curvature changing device according to claim 1, wherein the sensor unit senses a capacitance formed by the conductive aqueous solution and the electrode, corresponding to a size of an area of the boundary region between an insulator on the electrode and the conductive aqueous solution in the liquid lens or a change in the size.

3. The lens curvature changing device according to claim 2, wherein the sensor unit converts the sensed capacitance into a voltage signal.

4. The lens curvature changing device according to claim 2, further comprising:

a converter for converting a signal related to the capacitance sensed by the sensor unit into a digital signal.

5. The lens curvature changing device according to claim 1, wherein the sensor unit senses a potential difference or a current between the conductive aqueous solution and the electrode corresponding to a magnitude of an area of the boundary region between an insulator on the electrode and the conductive aqueous solution in the liquid lens or a change in the magnitude.

6. The lens curvature changing device according to claim 1, further comprising:

a plurality of wires for supplying a plurality of electrical signals output from the lens driver to the liquid lens; and

a switching element provided between any one of the plurality of conductive lines and the sensor unit.

7. The lens curvature changing device according to claim 6, wherein the sensor unit senses a size of an area of a boundary region between an insulator on the electrode and a conductive aqueous solution in the liquid lens or a change in the size during an on period of the switching element.

8. The lens curvature changing device according to claim 6, wherein the sensor unit senses a size of an area of the boundary region between an insulator on the electrode and a conductive aqueous solution in the liquid lens or a change in the size when a pulse signal is applied to at least one of the plurality of wires and the switching element is turned on.

9. The lens curvature changing device according to claim 1, wherein the liquid lens includes:

a common electrode;

a plurality of electrodes spaced apart from the common electrode; and

a liquid and the conductive aqueous solution disposed between the common electrode and the plurality of electrodes.

10. The lens curvature changing device according to claim 9, wherein the liquid lens further comprises:

a plurality of insulators for insulating the plurality of electrodes.

11. A lens curvature changing device according to claim 2, wherein the curvature of the liquid lens increases as the capacitance increases.

12. The lens curvature changing device according to claim 9, wherein a first capacitance of the first end portion of the liquid is different from a second capacitance of the second end portion of the liquid when different voltages are applied to a first capacitance and a second electrode of the plurality of electrodes.

13. A lens curvature changing device according to claim 9, wherein the curvature of the liquid lens increases as a time difference between a first pulse applied to the common electrode and a second pulse applied to any one of the plurality of electrodes increases.

14. The lens curvature changing device according to claim 9, wherein the controller calculates a curvature of the liquid lens based on a capacitance sensed by the sensor unit when a pulse is applied to at least one of the plurality of electrodes and the common electrode, and outputs a pulse width variation signal to the lens driver based on the calculated curvature and the target curvature driver.

15. The lens curvature changing device according to claim 14, wherein the controller controls the duty ratio of the pulse width variation signal to be increased when the calculated curvature is smaller than the target curvature.

16. The lens curvature changing device according to claim 14, wherein the controller includes:

an equalizer for calculating a curvature error based on the calculated curvature and the target curvature; and

a pulse width variation controller for generating and outputting the pulse width variation signal based on the calculated curvature error.

17. The lens curvature changing device according to claim 9, wherein the sensor unit includes:

a filter for filtering an electrical signal from at least one of the plurality of electrodes;

a peak detector for detecting a peak of the electric signal from the filter; and

an amplifier for amplifying the electrical signal from the peak detector.

18. The lens curvature changing device according to claim 9, wherein a pulse signal is applied to the common electrode during turn-on of a switching element connected to at least one of the plurality of electrodes,

wherein the sensor unit senses a capacitance of a boundary region between an insulator on the common electrode and a conductive aqueous solution in the liquid lens during a pulse signal application period in an on period of the switching element.

19. The lens curvature changing device according to claim 9, wherein the sensor unit includes:

a converting unit for converting a capacitance from at least one of the plurality of electrodes into a voltage; and

an amplifier for amplifying the voltage.

Technical Field

The present invention relates to a lens curvature changing device, and more particularly, to a lens curvature changing device capable of quickly and accurately sensing the curvature of a lens.

Background

A lens is a device that diverts the optical path. Lenses are used in various electronic devices, particularly video cameras.

The light passing through the lens in the camera is converted into an electric signal by the image sensor, and an image can be acquired based on the electric signal obtained by the conversion.

In order to adjust the focus of an image to be captured, the position of the lens needs to be changed. However, when the camera is used for a small electronic device, a considerable space needs to be secured to change the position of the lens, which causes inconvenience.

Therefore, a method for adjusting the focus of an image to be captured without changing the position of the lens is being studied.

Disclosure of Invention

Technical problem

Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a lens curvature changing device capable of quickly and accurately sensing the curvature of a lens.

Another object of the present invention is to provide a lens curvature changing device capable of quickly and accurately changing the curvature of a lens.

Technical scheme

In accordance with one aspect of the present invention, the above and other objects can be accomplished by the provision of a lens curvature changing device for changing a curvature of a liquid lens based on an applied electric signal, comprising: a lens driver for applying an electrical signal to the liquid lens; a sensor unit for sensing a curvature of the liquid lens formed based on the electrical signal; and a controller for controlling the lens driver based on the sensed curvature to form a target curvature of the liquid lens, wherein the sensor unit senses a size or a change in size of an area of a boundary region between the insulator on the electrode and the conductive aqueous solution in the liquid lens.

Advantageous effects

As is apparent from the above description, a lens curvature changing device according to an embodiment of the present invention is configured to change a variable curvature of a liquid lens based on an applied electric signal, and includes: a lens driver for applying an electrical signal to the liquid lens; a sensor unit for sensing a curvature of the liquid lens formed based on the electrical signal; and a controller for controlling the lens driver to form a target curvature of the liquid lens based on the sensed curvature. The sensor unit may quickly and accurately sense the curvature of the lens by sensing the size of the area of the boundary region between the insulator on the electrode and the conductive aqueous solution in the liquid lens or a change in the size.

In particular, the curvature of the lens can be accurately detected by sensing the capacitance corresponding to the size of the area of the boundary region between the insulator on the electrode and the conductive aqueous solution in the liquid lens or the change in the size.

The sensor unit may sense a capacitance corresponding to a size of an area of a boundary region between the insulator on the electrode and the conductive aqueous solution in the liquid lens or a change in the size, and feed back the capacitance to apply an electric signal to the liquid lens so that a curvature of the lens is changed. Thus, the curvature of the lens can be changed quickly and accurately.

The lens curvature changing device may include: a plurality of wires for supplying a plurality of electrical signals output from the lens driver to the liquid lens; and a switching element that is provided between one of the plurality of conductive lines and the sensor unit, and during an on period of the switching element, the sensor unit may sense a size of an area of a boundary region between the insulator on the electrode and the conductive aqueous solution in the liquid lens or a change in the size. Therefore, the curvature of the lens can be sensed quickly and accurately.

The lens curvature changing device may include: an equalizer for calculating a curvature error based on the calculated curvature and a target curvature; and a pulse width variation controller for generating and outputting a pulse width variation signal based on the calculated curvature error. Therefore, the curvature of the lens can be sensed quickly and accurately.

Drawings

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1A is a cross-sectional view of a camera according to an embodiment of the present invention;

FIG. 1B is an internal block diagram of the camera of FIG. 1A;

fig. 2 is a diagram illustrating a lens driving method;

fig. 3A and 3B are diagrams illustrating a method of driving a liquid lens;

fig. 4A to 4C are diagrams illustrating a structure of a liquid lens;

fig. 5A to 5E are diagrams illustrating changes in lens curvature of a liquid lens;

FIG. 6 is an exemplary internal block diagram of a camera associated with the present invention;

FIG. 7 is an exemplary internal block diagram of a camera according to an embodiment of the present invention;

fig. 8A to 12B are diagrams referred to in the description of fig. 7;

FIG. 13A is an exemplary internal block diagram of a camera according to another embodiment of the present invention;

fig. 13B is an exemplary internal block diagram of a video camera according to still another embodiment of the present invention.

Detailed Description

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

As used herein, the suffixes "module" and "unit" are interchangeably added or used to facilitate the preparation of this specification and are not intended to imply different meanings or functions. Thus, the terms "module" and "unit" may be used interchangeably.

Fig. 1A is a cross-sectional view of a camera according to an embodiment of the present invention.

First, fig. 1A is an example of a sectional view of the camera 195.

The camera 195 may include an aperture 194, a lens 193, and an image sensor 820.

The aperture 194 may block or allow light to be incident on the lens 193.

The image sensor 820 may include an RGB filter 910 and a sensor array 911 for converting an optical signal into an electrical signal to sense RGB colors.

Accordingly, the image sensor 820 may sense and output an RGB image.

Fig. 1B is an internal block diagram of the video camera of fig. 1A.

Referring to fig. 1B, the camera 195 may include a lens 193 and an image sensor 820 and an image processor 830.

The image processor 830 may generate an RGB image based on the electrical signal from the image sensor 820.

The exposure time may be adjusted based on the electrical signal from the image sensor 820.

Fig. 2 is a diagram illustrating a lens driving method.

Fig. 2(a) shows that light from the focal point 401 is transmitted to the lens 403, the beam splitter 405, the microlens 407, and the image sensor 409, and thus an image PH having a size Fa is formed on the image sensor 409.

In particular, fig. 2(a) shows that the focus is correctly formed corresponding to the focal point 401.

Next, fig. 2(b) shows that the lens 403 is moved toward the focal point 401 and an image PH having a size Fb smaller than Fa is focused on the image sensor 409, as compared with fig. 2A.

In particular, fig. 2(b) shows that the focus is excessively formed forward corresponding to the focal point 401.

Next, fig. 2(c) shows that the lens 403 is moved away from the focal point 401, and thus an image PH having a size Fc larger than Fa is focused on the image sensor 409.

In particular, fig. 2(c) shows that the focus is excessively formed backward corresponding to the focus 401.

That is, fig. 2 illustrates changing the position of the lens to adjust the focus of the captured image.

As shown in fig. 2, a Voice Coil Motor (VCM) is used to change the position of the lens 403.

However, when the VCM is used in a small electronic device such as the mobile terminal of fig. 1, the VCM requires a considerable space for the movement of the lens.

In the case where the camera 195 is used in a mobile terminal, an Optical Image Stabilization (OIS) function is required in addition to auto focusing.

Since the VCM allows only one-dimensional movement in a direction such as the left-right direction shown in fig. 2, it is not suitable for stabilizing an image.

To solve this problem, the present invention uses a liquid lens driving system instead of the VCM system.

In the liquid lens driving system, the curvature of the liquid lens is changed by applying an electric signal to the liquid lens, and thus it is not necessary to move the lens for autofocusing. In addition, the liquid lens driving system can prevent two-dimensional or three-dimensional blurring when implementing an image stabilization function.

Fig. 3A and 3B are diagrams illustrating a method of driving a liquid lens.

First, fig. 3a (a) shows that the first voltage V1 is applied to the liquid lens 500 and the liquid lens functions as a concave lens.

Next, fig. 3a (b) shows that the liquid lens 500 does not change the traveling direction of light when a second voltage V2 greater than the first voltage V1 is applied to the liquid lens 500.

Next, fig. 3a (c) shows that the liquid lens 500 functions as a convex lens when a third voltage V3 larger than the second voltage V2 is applied to the liquid lens 500.

Although it is illustrated in fig. 3A that the curvature or diopter of the liquid lens is changed according to the level of the applied voltage, the embodiment of the present invention is not limited thereto. The curvature or diopter of the liquid lens can be changed according to the pulse width of the applied pulse.

Next, fig. 3b (a) shows that the liquid in the liquid lens 500 has the same curvature and functions as a convex lens.

Referring to fig. 3b (a), the incident light Lpaa converges and outputs the corresponding output light Lpab.

Next, fig. 3b (b) shows that since the liquid in the liquid lens 500 has an asymmetric curved surface, the traveling light is turned upward.

Referring to fig. 3b (b), the incident light Lpaa converges upward, and outputs corresponding output light Lpac.

Fig. 4A to 4C are diagrams illustrating the structure of a liquid lens. In particular, fig. 4A is a top view of the liquid lens, fig. 4B is a bottom view of the liquid lens, and fig. 4C is a sectional view taken along line I-I' in fig. 4A and 4C.

In particular, fig. 4A corresponds to a right side surface of the liquid lens 500 in fig. 3A and 3B, and fig. 4B corresponds to a left side surface of the liquid lens 500 in fig. 3A and 3B.

Referring to the drawings, a common electrode (COM)520 may be disposed on the liquid lens 500, as shown in fig. 4A. The common electrode (COM)520 may be arranged in a tube shape, and the liquid 530 may be disposed in an area below the common electrode (COM)520, particularly, an area corresponding to the hollow.

Although not shown in the drawings, an insulator (not shown) may be disposed between the common electrode (COM)520 and the liquid to insulate the common electrode (COM).

As shown in fig. 4B, a plurality of electrodes (LA to LD)540a to 540d may be disposed below the common electrode (COM)520, particularly below the liquid 530. In particular, the plurality of electrodes (LA to LD)540a to 540d may be arranged to surround the liquid 530.

A plurality of insulators 550a to 550d for insulation may be disposed between the plurality of electrodes (LA to LD)540a to 540d and the liquid 530.

That is, the liquid lens 500 may include a common electrode (COM)520, a plurality of electrodes (LA to LD)540a to 540d spaced apart from the common electrode (COM), and a liquid 530 and a conductive aqueous solution 595 (see fig. 4C) disposed between the common electrode (COM)520 and the plurality of electrodes (LA to LD)540a to 540 d.

Referring to fig. 4C, the liquid lens 500 may include a plurality of electrodes (LA to LD)540a to 540d on a first substrate 510, a plurality of insulators 550a to 550d for insulating the plurality of electrodes (LA to LD)540a to 540d, a liquid 530 on the plurality of electrodes (LA to LD)540a to 540d, a conductive aqueous solution 595 on the liquid 530, a common electrode (COM)520 spaced apart from the liquid 530, and a second substrate 515 on the common electrode (COM) 520.

The common electrode 520 may be formed to have a hollow tubular shape. The liquid 530 and the conductive aqueous solution 595 may be disposed in the hollow region. The liquid 530 may be arranged in a circle as shown in fig. 4A and 4B. The liquid 530 may be a non-conductive liquid such as oil.

The size of the cross section of the hollow region may increase as it extends from the lower portion to the upper portion of the hollow region, and thus the lower portion of the plurality of electrodes (LA to LD)540a to 540d may be larger than the upper portion of the plurality of electrodes (LA to LD)540a to 540 d.

In fig. 4C, the first electrode (LA)540a and the second electrode (LB)540b of the plurality of electrodes (LA to LD)540a to 540d are arranged to be inclined, and the lower portion thereof is larger than the upper portion thereof.

As an alternative to the example of fig. 4A to 4C, the plurality of electrodes (LA to LD)540a to 540d may be disposed at an upper position, and the common electrode 520 may be disposed at a lower position.

Although fig. 4A to 4C illustrate that four electrodes are provided, the embodiment is not limited thereto. Two or more electrodes may be formed.

In fig. 4C, if a pulse-like electric signal is applied to the first electrode (LA)540a and the second electrode (LB)540b a predetermined time after the pulse-like electric signal is applied to the common electrode 520, a potential difference is generated between the common electrode 520, the first electrode (LA)540a, and the second electrode (LB)540 b. Then, the shape of the conductive aqueous solution 595 having conductivity is changed, and the shape of the liquid 530 in the liquid lens is changed according to the change of the shape of the conductive aqueous solution 595.

The present invention provides a method of simply and rapidly sensing the curvature of the liquid 530 formed according to the electric signals applied to the plurality of electrodes (LA to LD)540a to 540d and the common electrode 520.

According to the present invention, the sensor unit 962 senses the size of the area of the boundary region Ac0 between the first insulator 550a on the first electrode 540a and the conductive aqueous solution 595 in the liquid lens 500 or a change in the size.

In fig. 4C, AM0 is exemplarily given as the area of the boundary region Ac 0. In particular, it is shown that the area of the boundary region Ac0 contacting the conductive aqueous solution 595 in the inclined portion of the first insulator 550a on the first electrode 540a is AM 0.

In fig. 4C, it is shown that the liquid 530 is neither concave nor convex, but is parallel to the first substrate 510, etc. The curvature given in this case may be defined as, for example, 0.

As shown in fig. 4C, for the boundary area Ac0 contacting the conductive aqueous solution 595 in the inclined portion of the first insulator 550a on the first electrode 540a, the capacitance C may be formed according to equation 1.

[ equation 1]

Here, the dielectric constant of the dielectric 550a is represented, a represents the area of the boundary region Ac0, and d represents the thickness of the first dielectric 550 a.

Here, when the sum d is assumed to have a fixed value, the area of the boundary region Ac0 may greatly affect the capacitance C.

That is, as the area of the boundary region Ac0 increases, the capacitance C formed in the boundary region Ac0 may increase.

In the present invention, since the area of the boundary region Ac0 changes with a change in the curvature of the liquid 530, the area of the boundary region Ac0 or the capacitance C formed in the boundary region Ac0 is sensed using the sensor unit 962.

The capacitance of fig. 4C may be defined as CAc 0.

Fig. 5A to 5E are diagrams illustrating various curvatures of the liquid lens 500.

Fig. 5A shows a case in which a first curvature Ria is imparted to the liquid 530 in accordance with application of electric signals to the plurality of electrodes (LA to LD)540a to 540d and the common electrode 520.

In fig. 5A, it is shown that the area of the boundary region Aaa is AMa (> AM0) when the first curvature Ria is imparted to the liquid 530. In particular, it is shown that the area of the boundary region Aaa contacting the conductive aqueous solution 595 in the inclined portion of the first insulator 550a on the first electrode 540a is AMa.

According to equation 1, the area of the boundary region Aaa in fig. 5A is larger than that in fig. 4C, and thus the capacitance of the boundary region Aaa becomes larger. The capacitance in fig. 5A may be defined as CAaa, which is greater than the capacitance CAc0 in fig. 4C.

The first curvature Ria may be defined as a value having a positive polarity. For example, the first curvature Ria may be defined as having a level of + 2.

Fig. 5B illustrates a case in which the second curvature Rib is formed in the liquid 530 according to application of electric signals to the plurality of electrodes (LA to LD)540a to 540d and the common electrode 520.

In fig. 5B, since the second curvature Rib is formed in the liquid 530, AMb (> AMa) is exemplarily given as the area of the boundary region Aba. In particular, it is shown that the area of the boundary region Aba contacting the conductive aqueous solution 595 in the inclined portion of the first insulator 550a on the first electrode 540a is AMb.

According to equation 1, the area of the boundary region Aba in fig. 5B is larger than that of the boundary region Aba in fig. 5A, and thus the capacitance of the boundary region Aba becomes larger. The capacitance in fig. 5B may be defined as casa, which is larger than the capacitance CAaa in fig. 5A.

The second curvature Rib may be defined as a value having a positive polarity greater than the first curvature Ria. For example, the second curvature Rib may be defined to have a level of + 4.

Referring to fig. 5A and 5B, the liquid lens 500 functions as a convex lens, thereby outputting output light LP1a formed by condensing incident light LP 1.

Next, fig. 5C shows a case in which the third curvature Ric is formed in the liquid 530 according to application of electric signals to the plurality of electrodes (LA to LD)540a to 540d and the common electrode 520.

In particular, fig. 5C shows AMa given an area as the left boundary region Aca, and AMb (> AMa) given an area as the right boundary region Acb.

More specifically, the area of the boundary area Aca contacting the conductive aqueous solution 595 in the inclined portion of the first insulator 550a on the first electrode 540a is AMa, and the area of the boundary area Acb contacting the conductive aqueous solution 595 in the inclined portion of the second insulator 550b on the second electrode 540b is AMb.

Thus, the capacitance of the left boundary area Aca may be CAaa, and the capacitance of the right boundary area Acb may be CAba.

In this case, the third curvature Ric may be defined as a value having a positive polarity. For example, the third curvature Ric may be defined as having a level of + 3.

Referring to fig. 5C, the liquid lens 500 functions as a convex lens to output light LP1b by further condensing incident light LP1 to one side.

Next, fig. 5D shows a case in which the fourth curvature Rid is formed in the liquid 530 according to application of electric signals to the plurality of electrodes (LA to LD)540a to 540D and the common electrode 520.

In fig. 5D, since the fourth curvature Rid is formed in the liquid 530, AMd (< AM0) is exemplarily given as the area of the boundary region Ada. In particular, it is shown that the area of the boundary region (Ada) contacting the conductive aqueous solution 595 in the inclined portion of the first insulator 550a on the first electrode 540a is AMd.

According to equation 1, the area of the boundary region (Ada) in fig. 5D is smaller than that in fig. 4C, and thus the capacitance of the boundary region (Ada) is reduced. The capacitance in fig. 5D may be defined as CAda and has a value less than the capacitance CAc0 in fig. 4C.

In this case, the fourth curvature Rid may be defined as a value having a negative polarity. For example, the fourth curvature Rid may be defined to have a level of-2.

Next, fig. 5E shows a case where a fifth curvature Rie is formed in the liquid 530 according to application of electric signals to the plurality of electrodes (LA to LD)540a to 540d and the common electrode 520.

In fig. 5E, AMe (< AMd) is exemplarily given as an area of the boundary region Aea when the fifth curvature Rie is formed in the liquid 530. In particular, it is shown that the area of the boundary area Aea contacting the conductive aqueous solution 595 in the inclined portion of the first insulator 550a on the first electrode 540a is AMe.

According to equation 1, the area of the boundary region Aea in fig. 5E is smaller than that in fig. 5D, and thus the capacitance of the boundary region Aea becomes smaller. The capacitance in fig. 5E may be defined as CAea, which is smaller than the capacitance CAda in fig. 5D.

In this case, the fifth curvature Rie may be defined as a value having a negative polarity. For example, the fifth curvature Rie may be defined to have a level of-4.

Referring to fig. 5D and 5E, the liquid lens 500 functions as a concave lens to output light LP1c by diverging incident light LP 1.

Fig. 6 is an exemplary internal block diagram of a camera associated with the present invention.

Referring to fig. 6, the camera 195x may include a lens curvature changing device 800, an image sensor 820, an image processor 860, a gyro sensor 830, and a liquid lens 500.

The lens curvature changing device 800 may include a lens driver 860, a pulse width variation controller 840, and a power supply 890.

The operation of the lens curvature changing device 800 of fig. 6 is as follows. The pulse width variation controller 840 outputs a pulse width variation signal V corresponding to the target curvature, and the lens driver 860 may output corresponding voltages to the plurality of electrodes and the common electrode of the liquid lens 500 using the pulse width variation signal V and the voltage Vx of the power supply 890.

That is, the lens curvature changing device 800 of fig. 6 is used as an open loop system to change the curvature of the liquid lens.

According to this method, the curvature of the liquid lens 500 cannot be sensed except that the respective voltages are output to the plurality of electrodes and the common electrode of the liquid lens 500 according to the target curvature.

In addition, according to the lens curvature changing device 800 of fig. 6, when it is necessary to change the curvature of the liquid lens 500 to prevent blurring, since the curvature is not sensed, it may be difficult to accurately change the curvature.

Therefore, in the present invention, the lens curvature variable device 800 is implemented not as an open-loop system as shown in fig. 6 but as a closed-loop system.

That is, in order to recognize the curvature of the liquid lens 500, the capacitance formed in the insulator on the electrode in the liquid lens 500 and in the boundary region Ac0 contacting the conductive aqueous solution 595 is sensed, and the capacitance is fed back to calculate the difference between the target curvature and the current curvature, and a control operation corresponding to the difference is performed.

Accordingly, the curvature of the liquid lens 500 may be quickly and accurately recognized, and the curvature of the liquid lens 500 may be quickly and accurately controlled so as to correspond to a target curvature. This operation will be described in more detail with reference to fig. 7 and subsequent figures.

Fig. 7 is an exemplary internal block diagram of a video camera according to an embodiment of the present invention.

Referring to fig. 7, the camera 195m according to an embodiment of the present invention may include: a lens curvature changing device 900 for changing the curvature of the liquid lens 500; an image sensor 820 for converting light from the liquid lens 500 into an electrical signal; and an image processor 930 for performing image processing based on the electric signal from the image sensor 820. Image processing apparatus

The camera 195m of fig. 7 may also include a gyro sensor 915.

The image processor 930 may output focus information AF on the image, and the gyro sensor 915 may output blur information OIS.

Accordingly, the controller 970 in the lens curvature changing device 900 may determine the target curvature based on the focus information AF and the blur information OIS.

The lens curvature control apparatus 900 according to an embodiment of the present invention may include: a lens driver 960 for applying an electrical signal to the liquid lens 500; a sensor unit 962 for sensing a curvature of the liquid lens 500 formed based on the electric signal; and a controller 970 for controlling the lens driver 960 based on the sensed curvature to form a target curvature of the liquid lens 500. The sensor unit 962 can sense the size of the area of the boundary region Ac0 between the insulator on the electrode and the conductive aqueous solution 595 in the liquid lens 500 or a change in the size. Therefore, the curvature of the lens can be sensed quickly and accurately.

According to an embodiment of the present invention, the lens curvature changing device 900 may further include a liquid lens 500, the liquid lens 500 having a curvature that changes based on an applied electric signal.

According to an embodiment of the present invention, the lens curvature controlling apparatus 900 may include: a power supply 990 for supplying power; and an analog-to-digital (AD) converter (not shown) for converting a signal related to the capacitance sensed by the sensor unit 962 into a digital signal.

The lens curvature changing device 900 may include: a plurality of wires CA1 and CA2 for supplying an electric signal from the lens driver 960 to each of the electrodes (common electrode and plurality of electrodes) in the liquid lens 500 driver; and a switching element SWL provided between the sensor unit 962 and one of the conductive lines CA 2.

The figure shows that a switching element SWL is provided between the sensor unit 962 and a wire CA2 for applying an electrical signal to any one of the plurality of electrodes in the liquid lens 500. In this case, a contact point between the wire CA2 and one end of the switching element SWL or the liquid lens 500 may be referred to as a node a.

In the present invention, an electrical signal is applied to each of the electrodes (common electrode and plurality of electrodes) in the liquid lens 500 through a plurality of wires CA1 and CA2 to sense the curvature of the liquid lens 500. Accordingly, a curvature may be imparted to the liquid 530, as shown in fig. 5A to 5E.

For example, during the first period, the switching element SWL may be turned on.

If an electrical signal is applied to the electrodes in the liquid lens 500 when the switching element SWL is turned on and thus electrically connected to the sensor unit 962, a curvature may be formed in the liquid lens 500, and an electrical signal corresponding to the curvature may be provided to the sensor unit 962 via the switching element SWL.

Accordingly, during the on period of the switching element SWL, the sensor unit 962 may sense the size of the area of the boundary region Ac0 between the insulator on the electrode and the conductive aqueous solution 595 in the liquid lens 500 or a change in the size, or sense the capacitance of the boundary region Ac0, based on the electrical signal from the liquid lens 500.

Next, during the second period, the switching element SWL may be turned off, and an electric signal may be continuously applied to the electrodes in the liquid lens 500. Accordingly, a curvature may be formed in the liquid 530.

Next, during the third period, the switching element SWL may be turned off, and no electric signal or a low-level electric signal may be applied to the electrode in the liquid lens 500.

Next, during a fourth period, the switching element SWL may be turned on.

If an electrical signal is applied to the electrode in the liquid lens 500 when the switching element SWL is turned on and electrically connected to the sensor unit 962, a curvature may be formed in the liquid lens 500, and an electrical signal corresponding to the curvature may be provided to the sensor unit 962 via the switching element SWL.

If the curvature calculated based on the capacitance sensed during the first period is less than the target curvature, the controller 970 may control the pulse width of the pulse width variation control signal to be supplied to the driver 960 to be increased in order to obtain the target curvature.

Accordingly, the time difference between the pulses applied to the common electrode 530 and the plurality of electrodes may be increased, thereby increasing the curvature formed in the liquid 530.

If an electrical signal is applied to an electrode in the liquid lens 500 with the switching element SWL turned on and electrically connected with the sensor unit 962 during the fourth period, a curvature may be formed in the liquid lens 500, and an electrical signal corresponding to the curvature may be provided to the sensor unit 962 via the switching element SWL.

Accordingly, during the on period of the switching element SWL, the sensor unit 962 may sense the size of the area of the boundary region Ac0 between the insulator on the electrode and the conductive aqueous solution 595 in the liquid lens 500 or a change in the size, or sense the capacitance of the boundary region Ac0, based on the electrical signal from the liquid lens 500.

Accordingly, controller 970 may calculate the curvature based on the sensed capacitance and may determine whether the curvature has reached the target curvature. If the curvature has reached the target curvature, the controller 970 may control the corresponding electrical signal to be provided to each of the electrodes.

When an electrical signal is provided, the curvature of the liquid 530 may be formed and may be immediately sensed. Accordingly, the curvature of the liquid lens 500 can be quickly and accurately recognized.

Lens driver 960 and sensor unit 962 may be implemented by a single module 965.

The lens driver 960 and the sensor unit 962, the controller 970, the power supply 990, the AD converter 967, and the switch unit SWL shown in the drawing may be implemented by a single System On Chip (SOC).

As shown in fig. 4A to 4C, the liquid lens 500 may include a common electrode (COM)520, a liquid 530 on the common electrode (COM)520, a conductive aqueous solution 595 on the liquid 530, and a plurality of electrodes (LA to LD) spaced apart from the liquid 530.

As shown in fig. 5A to 5E, the sensor unit 962 may sense the size of the area of the boundary region Ac0 between the insulator on the electrode and the conductive aqueous solution 595 in the liquid lens 500 or a change in the size, or may sense a capacitance corresponding thereto.

An analog signal related to the capacitance sensed by the sensor unit 962 may be converted into a digital signal by the AD converter 967 and input to the controller 970.

As shown in fig. 5A to 5E, as the curvature of the liquid lens 500 increases, the area of the boundary region Ac0 increases, and thus the capacitance of the boundary region Ac0 increases.

In the present invention, it is assumed that the curvature is calculated using the capacitance sensed by the sensor unit 962.

The controller 970 may control the level of the voltage to be applied to the liquid lens 500 to be increased or the pulse width to be increased in order to increase the curvature of the liquid lens 500.

As shown in fig. 5C, when voltages of different levels or different pulse widths are applied to the first electrode 540a and the third electrode 540C of the plurality of electrodes (LA to LD)540a to 540d, a first capacitance of the first end portion Aca of the liquid 530 and a second capacitance of the second end portion Acb of the liquid 530 are different from each other.

Accordingly, the sensor unit 962 may sense the capacitances of the first and second end portions Aca and Acb of the liquid 530, respectively.

By sensing the capacitance around the end of the liquid 530 in the liquid lens 500, the curvature of the lens can be accurately detected.

In other words, by sensing the capacitance of a plurality of boundary regions between the insulator on the electrode and the conductive aqueous solution 595 in the liquid lens 500, the curvature of the liquid lens can be accurately detected.

When a constant voltage is applied to the common electrode (COM)520 and a pulse is applied to the plurality of electrodes (LA to LD)540a to 540d, the sensor unit 962 may sense the capacitances of the plurality of boundary areas between the insulators on the plurality of electrodes (LA to LD)540a to 540d and the conductive aqueous solution 595.

When a constant voltage is applied to the plurality of electrodes (LA to LD)540a to 540d and a pulse is applied to the common electrode COM 520, the capacitance of the boundary area between the insulator on the first electrode 520 and the conductive aqueous solution 595 may be sensed.

Controller 970 may calculate the curvature of liquid lens 500 based on the capacitance sensed by sensor unit 962.

The controller 970 may calculate the curvature of the liquid lens 500 such that the curvature increases as the capacitance sensed by the sensor unit 962 increases.

Then, the controller 970 may control the liquid lens 500 to have a target curvature.

The controller 970 may calculate the curvature of the liquid lens 500 based on the capacitance sensed by the sensor unit 962 and output a pulse width variation signal V to the lens driver 960 based on the calculated curvature and the target curvature.

Then, the lens driver 960 may output corresponding electrical signals to the plurality of electrodes (LA to LD)540a to 540d and the common electrode (520) using the pulse width variation signal V and the voltages Lv1 and Lv2 of the power supply 990.

Accordingly, since the capacitance of the liquid lens 500 is sensed and fed back and an electrical signal is applied to the liquid lens 500 to change the curvature of the lens, the curvature of the lens can be changed quickly and accurately.

The controller 970 may include: an equalizer 972 for calculating a curvature error based on the calculated curvature and a target curvature; and a pulse width variation controller 940 for generating and outputting a pulse width variation signal V based on the calculated curvature error Φ.

Accordingly, if the calculated curvature is greater than the target curvature, the controller 970 may control the duty ratio of the pulse width variation signal V to be increased or control the delay corresponding to the time difference between a plurality of pulses applied to the liquid lens 500 to be increased based on the calculated curvature error Φ. Accordingly, the curvature of the lens 500 can be changed quickly and accurately.

The controller 970 may receive the focus information AF from the image processor 930 and the blur information OIS from the gyro sensor 915, and determine the target curvature based on the focus information AF and the blur information OIS.

Here, the update period of the determined target curvature is preferably longer than the update period of the curvature calculated based on the sensing capacitance of the liquid lens 500.

Since the update period of the calculated curvature is shorter than that of the target curvature, the curvature of the liquid lens 500 can be quickly changed to a desired curvature.

Fig. 8A to 12B are diagrams referred to in the description of fig. 7.

Fig. 8A shows curvature change curves of the liquid lens 500 in the liquid curvature changing device 800 of fig. 6 and the lens curvature changing device 900 of fig. 7.

Referring to fig. 8A, GRo represents a curvature change curve of the liquid lens 500 in the lens curvature changing device 800 of fig. 6, and GRc represents a curvature change curve of the liquid lens 500 in the lens curvature changing device 900 of fig. 7.

In particular, the figure shows a case where a voltage for changing the curvature to the target curvature is applied to the liquid lens 500 at time Tx and the voltage is interrupted at time Ty.

Although not precise, it can be seen from these two curves that the change in curvature is slowly stabilized to the target diopter in the case of the lens curvature changing device 800 of fig. 6 of the open-loop system, and the change in curvature is rapidly and precisely stabilized in the case of the lens curvature changing device 900 of fig. 7 of the closed-loop system.

The lens curvature changing device 900 of fig. 7 of the closed-loop system may have a settling time that is about 70% shorter than the lens curvature changing device 800 of fig. 6 of the open-loop system.

Accordingly, with the lens curvature changing device 900 of fig. 7 of the closed-loop system, curvature and diopter can be quickly and accurately formed.

The diopter may correspond to the curvature of the liquid 530 shown in fig. 5A-5E. Thus, it can be defined that the refractive power increases with increasing curvature of the liquid 530 and decreases with decreasing curvature.

For example, as shown in fig. 5A and 5B, when the curvature has a level of +2 or +4, the diopter may be defined to have a level of +2 or +4 corresponding to the convex lens. When the curvature has a level of 0, the diopter may be defined to have a level of 0 corresponding to the planar lens. When the curvature has a level of-2 or-4 as shown in fig. 5D and 5E, the diopter can be defined as having a level of-2 or-4 corresponding to the concave lens.

Fig. 8B is a timing diagram of the common electrode COM, the first electrode LA, and the switching element SWL in the lens curvature changing device 900 of fig. 7.

Referring to fig. 8B, the switching element SWL is turned on during a period Dt1 between time T1 and time T3.

In order to sense the capacitance of the boundary region Ac0 by the sensor unit 962, a curvature is preferably formed in the liquid lens 500 during a period Dt1 between time T1 and time T3.

To ensure accuracy and stability of the sensing operation of the sensor unit 962 in the present invention, a pulse is applied to the common electrode and one of the plurality of electrodes in the liquid lens 500 during a period Dt1 between time T1 and time T3.

In particular, as shown in fig. 8B, at time T2, a pulse having a pulse width Dt2 may be applied to the common electrode 530. Therefore, after time T2, the curvature of the liquid lens 500 may be formed.

Accordingly, during the period between the time T2 and the time T3 in the period Dt1 between the time T1 and the time T3, the sensor unit 962 can sense the capacitance formed by the conductive aqueous solution 595 and the electrodes according to the size of the area of the boundary region Ac0 between the insulator on the electrodes and the conductive aqueous solution 595 in the liquid lens 500 or a change in the size.

During the period between time T2 and time T3, the sensor unit 962 may sense a potential difference or current between the conductive aqueous solution 595 and the electrode, which corresponds to the size or change in the size of the area of the boundary region Ac0 between the insulator on the electrode and the conductive aqueous solution 595 in the liquid lens 500.

Next, at time T4, a pulse having a pulse width Dt3 may be applied to the first electrode LA.

That is, a high-level voltage may be applied to the common electrode COM at a time point T2, and a high-level voltage may be applied to the first electrode LA at a time point T4.

The curvature formed in the liquid 530 in the liquid lens 500 may vary according to a time difference DFF1 between a pulse applied to the common electrode COM and a pulse applied to the first electrode LA.

For example, as the time difference DFF1 between pulses increases, the area of the boundary region Ac0 where the electrode is in contact with the conductive aqueous solution 595 may increase, and thus the capacitance and curvature may increase.

Fig. 9A and 9B are diagrams illustrating various sensing methods for the sensor unit.

FIG. 9A shows a sensor unit 962a capable of sensing capacitance without applying a separate additional pulse signal.

The sensor unit 962a in the lens curvature changing device 900a of fig. 9A may operate in a continuous sensing manner.

To this end, the sensor unit 962a of fig. 9A may include: a filter 1112 for filtering an electric signal from at least one of the plurality of electrodes (LA to LD)540a to 540 d; a peak detector 1114 for detecting a peak of the electrical signal; and a Programmable Gain Amplifier (PGA)1116 for amplifying the electrical signal from the peak detector 1114.

Specifically, the sensor unit 962a of fig. 9A may sense the capacitance of the liquid lens 500 during an on period of the switching element SWL connected to at least one of the plurality of electrodes (LA to LD)540a to 540 d.

Next, fig. 9B shows a sensor unit 962B capable of applying a separate additional pulse signal to the common electrode (COM)520 and sensing capacitance during application of the additional pulse signal.

The sensor unit 962B in the lens curvature changing device 900B of fig. 9B may operate in a discrete sensing manner.

To this end, the sensor unit 962B of fig. 9B may include: a conversion unit 1122 for converting capacitance from at least one of the plurality of electrodes (LA to LD)540a to 540d into a voltage; and an amplifier 1124 for amplifying the voltage.

More specifically, during the on period of the switching element SWL connected to at least one of the electrodes (LA to LD)540a to 540d, an additional pulse signal may be applied to the common electrode (COM)520, and the sensor unit 962B of fig. 9B may sense the capacitance of the liquid lens 500 formed based on the additional pulse signal.

A lens driver that can be applied to both fig. 9A and 9B may be as shown in fig. 10.

Fig. 10 is an exemplary internal circuit diagram of the lens driver of fig. 9A or 9B.

Referring to fig. 10, the lens driver 960a of fig. 10 may include a first driver 961 for driving a lens and a second driver 1310 for driving a sensor.

The lens driver 960a may further include a pulse width controller 1320, the pulse width controller 1320 for outputting a pulse width change signal to the second driver 1310.

The pulse width controller 1320 may be provided in the pulse width controller 940 of fig. 7.

The first driver 961 may include a first upper arm switching element Sa and a first lower arm switching element S 'a connected in series to each other and a second upper arm switching element Sb and a second lower arm switching element S' b connected in series to each other.

Here, the first upper arm switching element Sa and the first lower arm switching element S 'a and the second upper arm switching element Sb and the second lower arm switching element S' b are connected in parallel to each other.

Power of a level LV2 from a power supply 990 may be supplied to the first upper arm switching element Sa and the second upper arm switching element Sb.

The second driver 1310 may include a third upper arm element Sc and a third lower arm element S' c connected in series to each other.

Power of a level LV1 lower than the level LV2 from the power supply 990 may be supplied to the third upper arm switching element Sc to generate an additional low-level pulse.

A voltage may be applied to the common electrode 520 through a node between the first upper arm switching element Sa and the first upper arm switching element S ' a or a node between the third upper arm switching element Sc and the third lower arm switching element S ' c, and a voltage may be applied to the first electrode (LA)540a through a node between the second upper arm switching element Sb and the second lower arm switching element S ' b.

Fig. 11A is an exemplary waveform diagram for explaining the operation of the lens driver 960a of fig. 10, and fig. 11B is an exemplary diagram referred to for explaining the operation of the sensor unit 962a of fig. 9A.

Referring to fig. 11A, during a period Dt1 between time T1 and time T3, a high level is applied to the switching element SWL to turn on the switching element SWL.

During a period Dt1 between time T1 and time T3, the low-level control signals LAP and LAM are applied to the switching element Sb and the switching element S 'b, respectively, and thus the switching element Sb and the switching element S' b float.

The switching element Sb and the switching element S' b are complementarily turned on. However, during the period in which the switching element SWL is turned on, both the switching elements are floated.

At time T2, the control signal CMHP applied to the switching element Sa switches to the high level, and the control signal CMHM applied to the switching element S' a switches to the low level.

The switching element Sa and the switching element S' a are always complementarily turned on.

At time T2, the control signal CMHP applied to the switching element Sa switches to the high level. At time T4, the control signal LAp applied to the switching element Sb switches to the high level.

During a period Dt1 between time T1 and time T3, a pulse having a pulse width Dt2 may be applied at time T2. Therefore, after time T2, the curvature of the liquid lens 500 may be formed.

Accordingly, during a period between time T2 and time T3 in the period Dt1 between time T1 and time T3, the sensor unit 962 can sense a capacitance corresponding to the size of the area of the boundary region Ac0 between the insulator on the electrode and the conductive aqueous solution 595 in the liquid lens 500 or a change in the size.

Specifically, during the period between time T2 and time T3, the signal of level Lv3 may be applied to the filter 1112, the peak detector 114 may detect the signal, and the PGA 1116 may amplify the signal. Accordingly, during the period between the time T2 and the time T3, the capacitance corresponding to the size of the area of the boundary region Ac0 between the insulator on the electrode and the conductive aqueous solution 595 in the liquid lens 500 or the change in the size can be sensed.

At time T2, a high-level voltage may be applied to the common electrode COM, and at time T4, a high-level voltage may be applied to the first electrode LA.

The curvature formed in the liquid 530 in the liquid lens 500 may vary according to a time difference DFF1 between a pulse applied to the common electrode COM and a pulse applied to the first electrode LA.

For example, as the time difference DFF1 between pulses increases, the area of the boundary region Ac0 where the electrode is in contact with the conductive aqueous solution 595 may increase, and thus the capacitance may increase.

In the example of fig. 11A, the second driver 1310 of fig. 10 does not operate.

Next, the common electrode 520 is grounded at time T5, and the first electrode (LA)540a is grounded at time T6. Thereafter, the operations at times T1 and T2 are repeated at times T7 and T8.

Fig. 11C is another exemplary waveform diagram illustrating an operation of the lens driver 960a of fig. 10, and fig. 11D is a diagram illustrating an operation of the sensor unit 962a of fig. 9A.

Fig. 11C is similar to the waveform diagram of fig. 11A, except that control signals CMLP and CMLM for operating the switching elements Sc and S' C in the second driver 1310 of fig. 10 are provided.

During the period between T1 and T2, the sensor unit SWL is turned on, and is turned off after T2.

At time T2, the control signal CMHP applied to the switching element Sa switches to the high level. At time T3, the control signal LAp applied to the switching element Sb switches to the high level.

During a period between T1 and T2, the switching element Sc may be turned on. Then, as shown in fig. 11D, an additional pulse SMP having a level Lv1 supplied from a power supply 990b may be applied to the common electrode COM.

Thus, during a period Dt1 between time T1 and time T2, the sensor unit 962 can sense a capacitance corresponding to a size of an area of a boundary region Ac0 between an insulator on an electrode and the conductive aqueous solution 595 in the liquid lens 500 or a change in the size.

Specifically, during the period between times T1 and T2, a signal of a level Lv5 lower than the level Lv3 may be applied to the filter 1112, the peak detector 114 may detect the signal, and the PGA 1116 may amplify the signal. Accordingly, during the period between the time T1 and the time T2, the capacitance corresponding to the size of the area of the boundary region Ac0 between the insulator on the electrode and the conductive aqueous solution 595 in the liquid lens 500 or the change in the size can be sensed.

Next, at time T3, a pulse SLP having a pulse width Dt2 and a level Lv2 higher than the level Lv1 may be applied to the common electrode COM.

Next, at time T4, a pulse having a pulse width Dt3 may be applied to the first electrode LA.

The curvature formed in the liquid 530 in the liquid lens 500 may vary according to a time difference DFF1 between a pulse applied to the common electrode COM and a pulse applied to the first electrode LA.

For example, as the time difference DFF1 between pulses decreases, the area of the boundary region Ac0 where the electrode is in contact with the conductive aqueous solution 595 may increase, and thus the capacitance may increase. As a result, the curvature can be reduced.

Fig. 11E is another exemplary waveform diagram illustrating an operation of the lens driver 960a of fig. 10, and fig. 11F is a diagram illustrating an operation of the sensor unit 962B of fig. 9B.

Fig. 11E is a waveform diagram similar to fig. 11C. However, unlike fig. 11C, during the period from T1 to T2, the control signals CMLP and CMLM for operating the switching elements Sc and S' C in the second driver 1310 of fig. 10 have a plurality of pulses instead of a single pulse.

Therefore, as shown in fig. 11F, during a period from T1 to T2, a plurality of pulses SMPa are applied to the common electrode COM.

Thus, during a period Dt1 between time T1 and time T2, the sensor unit 962 can sense a capacitance corresponding to a size of an area of a boundary region Ac0 between an insulator on an electrode and the conductive aqueous solution 595 in the liquid lens 500 or a change in the size.

Specifically, during the period between time T1 and time T2, a plurality of pulse signals Lv3 may be applied to the C2V converter 1122, and the SC amplifier 1124 may amplify the plurality of pulse signals. Accordingly, during the period between the time T1 and the time T2, the capacitance corresponding to the size of the area of the boundary region Ac0 between the insulator on the electrode and the conductive aqueous solution 595 in the liquid lens 500 or the change in the size can be sensed. In particular, a voltage signal corresponding to the capacitance may be output as an output of the sensor portion 962.

Fig. 13A is an exemplary internal block diagram of a video camera according to another embodiment of the present invention.

Referring to fig. 13A, a camera 195n and a lens curvature changing device 900b shown in fig. 13A are similar to the camera 195m and the lens curvature changing device 900 shown in fig. 7 except that capacitances of end portions of a plurality of liquids 530 corresponding to a plurality of electrodes (LA to LD)540a to 540d are sensed.

For this, a low-level voltage is applied to the common electrode (COM)520, and a pulse signal may be applied to the plurality of electrodes (LA to LD)540a to 540 d.

Preferably, in order to allow the operation of the sensor unit 962, a plurality of switching elements SWLa to SWLd are provided between the conductive lines CA to CD, which are connected between the plurality of electrodes (LA to LD) and the liquid lens 500, and the sensor unit 962.

During a period in which the plurality of switching elements SWLa to SWLd are turned on, the sensor unit 962 may sense the capacitance of the boundary area between the conductive aqueous solution and the insulators on the plurality of electrodes (LA to LD)540a to 540d based on the pulse signal applied to the plurality of electrodes (LA to LD)540a to 540d, and may transmit the sensed capacitance to the controller 970.

Accordingly, the capacitance of a plurality of boundary regions of the liquid lens 500 can be sensed.

Further, the camera 195n of fig. 13A may change the voltages applied to the plurality of electrodes (LA to LD)540a to 540d for blur correction, thereby forming an asymmetric curvature. Blur correction can be performed accurately and quickly.

Fig. 13B is an exemplary internal block diagram of a video camera according to still another embodiment of the present invention.

Referring to fig. 13B, a camera 195o and a lens curvature changing device 900c shown in fig. 13B are similar to the camera 195m and the lens curvature changing device 900 shown in fig. 7 except that the capacitance of the end portion of the liquid corresponding to the plurality of electrodes (LA to LD)540a to 540d is sensed.

For this, a low-level voltage may be applied to the plurality of electrodes (LA to LD)540a to 540d, and a pulse signal may be applied to the common electrode (COM).

Preferably, in order to allow the operation of the sensor unit 962, a switching element SWL is provided between the sensor unit 962 and a conductive line CM connected between the common electrode COM and the liquid lens 500 (instead of the conductive lines CA to CD connected between the plurality of electrodes (LA to LD)540a to 540d and the liquid lens 500).

During a period in which the switching element SWL is turned on, the sensor unit 962 may sense the capacitance of the boundary area between the insulator on the electrode and the conductive aqueous solution based on the pulse signal applied to the common electrode COM, and may transmit the sensed capacitance to the controller 970.

Accordingly, the capacitance of the boundary region of the liquid lens 500 can be sensed.

Further, the camera 195o of fig. 13B can form an asymmetric curvature in response to blur correction, and thus can accurately and quickly perform blur correction.

The lens curvature changing device 900 described with reference to fig. 9 to 15B may be used for various electronic devices, such as mobile terminals, vehicles, TVs, drones, robots, and robot cleaners.

The operation method of the lens curvature changing apparatus of the present invention may be implemented as a code on a recording medium that is readable by a processor included in the lens curvature changing apparatus. The processor-readable recording medium may include all types of recording devices that store data readable by a processor. Examples of the recording medium readable by the processor include ROM, RAM, CD-ROM, magnetic tapes, floppy disks, and optical data storage devices, and may also be implemented in the form of carrier waves, such as transmission through the internet. Further, the processor-readable recording medium may be distributed over network-coupled computer systems so that codes readable by the processor in a distributed manner may be stored and executed.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Industrial applicability

The present invention is applicable to a lens curvature changing device capable of quickly and accurately sensing the curvature of a lens.