Patent Description:
<CIT> discloses a drive circuitry for driving a plurality of liquid lenses. Each liquid lens comprises first and second immiscible liquids. An interface between the first and second liquids is movable by electrowetting by application of a drive voltage signal. The drive circuitry is arranged to generate an independent drive voltage Signal for each of the liquid lenses. <CIT> relates to a liquid lens driving circuit that generates a liquid lens driving signal and to a liquid lens driving circuit integrated with the liquid lens driving circuit. The liquid lens driving circuit generates a high voltage driving signal from a low voltage source. A differential type driving signal is generated to improve the root mean square (RMS) voltage between two electrodes of the liquid lens applied by the high voltage driving signal that drives the liquid lens. Users of portable devices desire to own optical devices having high resolution, small size, and various capture functions. The various capture functions include, for example, an auto-focus (AF) function and an optical image stabilization (OIS) function for compensating for tremor of user's hands or counteracting shaking of an optical device. Such capture functions may be implemented through a method of combining multiple lenses to directly move the lenses. However, if the number of lenses increases, the size of the optical device may increase. To perform the AF and OIS functions, a module of multiple lenses which are fixed in a lens holder and have arranged optical axes moves or tilts in the direction of the optical axes or in a vertical direction of the optical axes and an additional lens driving device is used to drive the lens module. However, the lens driving device has high power consumption and is thick in thickness because a cover glass for protecting the lens module should be provided separately from a camera module. Accordingly, studies on a liquid lens for performing the AF and OIS functions by electrically adjusting the curvature of an interface of two types of liquid have been conducted.

According to embodiments, in a camera module including a lens capable of adjusting a focal length using electrical energy, a high driving voltage is generated to drive the lens even by a low voltage, using a switching circuit and a negative voltage, thereby reducing the size of an integrated circuit for controlling the lens.

Further, according to embodiments, a positive voltage and a negative voltage are alternately supplied to a common electrode even when a low voltage is supplied to a plurality of terminals of a lens capable of adjusting a focal length, thereby generating a high voltage for driving the lens.

Still further, according to embodiments, distortion of an interface which may occur when the difference in voltage between electrodes increases is prevented by floating partial electrodes to control a driving voltage of a lens capable of adjusting a focal length, thereby more stably performing optical image stabilization, i.e., an OIS function.

Still further, according to embodiments, a pulse of a voltage provided to a common terminal and a plurality of terminals is controlled in detail using floating to control a driving voltage of a lens capable of adjusting a focal length, thereby raising resolution and a range of lens control.

Still further, embodiments are applied to a portable device and a circuit for controlling a lens adjusting a focal length in correspondence to a driving voltage applied between a common terminal and a plurality of terminals uses a ground voltage as a power voltage, thereby reducing power consumption of the circuit and a camera module.

The technical objects that can be achieved through the present invention are not limited to what has been particularly described hereinabove and other technical objects not described herein will be more clearly understood by persons skilled in the art from the following detailed description.

The second voltage generator may include a charge pump for receiving the first voltage from the first voltage generator and changing a polarity of the first voltage to output the first voltage having the changed polarity.

The first voltage may have a positive polarity and the second voltage generator may output the second voltage of a negative polarity having the same magnitude as the first voltage independently of the first voltage generator.

Switching elements included in at least one first switch may be commonly disposed in the plural subelectrodes of the individual electrode and switching elements included in plural third switches may be independently disposed in each subelectrode of the individual electrode.

Subelectrodes of at least two individual electrodes disposed at a symmetrical location based on the center of the liquid lens among plural electrode sectors may be floated during a preset time.

All of the subelectrodes of the individual electrode may be floated during a preset time.

In another embodiment, a method of controlling a liquid lens having a plurality of subelectrodes including a first subelectrode may include applying a first voltage, a second voltage having a polarity opposite to the first voltage, or a ground voltage to the first subelectrode; floating the first subelectrode during a preset time; and applying the first voltage, the second voltage, or the ground voltage after floating the first subelectrode during a preset time.

The third switch may include a first switch element connected to the first switch and a second switch element connected to the second switch and cut off the first switch element and the second switch element during a preset time to prevent the first voltage, the second voltage, or the ground voltage from being transmitted to the at least one subelectrode.

The above technical solutions are merely some parts of the embodiments of the present invention and various embodiments into which the technical features of the present invention are incorporated can be derived and understood by persons skilled in the art from the following detailed description of the present invention.

The effects of the device according to the present invention are as follows.

Embodiments may achieve a compact size of an element constituting an integrated circuit for controlling a lens by generating a driving voltage of the lens capable of adjusting a focal length using a negative voltage.

Further, embodiments may reduce the size of a circuit for generating a supply voltage for controlling a lens capable of adjusting a focal length, and raise productivity and decrease manufacturing cost because resolution and a range may be ensured even by a low-end control circuit.

Still further, embodiments increase a range within which an image may be corrected through optical image stabilization (OIS) and perform efficient image correction by performing a stable optical image stabilization function, i.e., OIS function even when there is a big difference in driving voltage between electrodes in a process of controlling movement of an interface in a liquid lens.

It will be appreciated by persons skilled in the art that that the effects that can be achieved through the present invention are not limited to what has been particularly described hereinabove and other advantages of the present invention will be more clearly understood from the following detailed description.

While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings.

While terms, such as "first", "second", etc., may be used to describe various components, such components must not be limited by the above terms. The above terms are used only to distinguish one component from another. In addition, terms particularly defined in consideration of construction and operation of the embodiments are used only to describe the embodiments and do not define the scope of the embodiments.

In the description of the embodiments, it will be understood that, when an element is referred to as being formed "on" or "under" another element, it can be directly "on" or "under" the other element or be indirectly formed with intervening elements therebetween. It will also be understood that, when an element is referred to as being "on" or "under," "under the element" as well as "on the element" can be included based on the element.

As used herein, relational terms, such as "on"/"upper part"/"above", "under"/"lower part"/"below," and the like, are used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements.

<FIG> illustrates problems of a method of controlling a lens capable of adjusting a focal length using electrical energy. Specifically, <FIG> illustrates a control circuit for applying a driving voltage to a lens and <FIG> is a waveform diagram illustrating a method of applying a driving voltage to a lens.

Referring to <FIG>, the control circuit may include a voltage booster <NUM> for receiving a supply voltage VIN and boosting the level of the received voltage, a voltage stabilizer <NUM> for stabilizing the output of the voltage booster <NUM>, and a switching unit <NUM> for selectively supplying the output of the voltage booster <NUM> to a lens <NUM>.

Herein, the switching unit <NUM> may include a circuit configuration typically called an H bridge. A high voltage output from the voltage booster <NUM> is applied as a power voltage of the switching unit <NUM>. The switching unit <NUM> may selectively supply the applied power voltage and a ground voltage to both terminals of the lens <NUM>.

Referring to <FIG>, a voltage of a pulse type having a predetermined width may be applied to the both terminals of the lens <NUM>, i.e., a common terminal C0 and an individual electrode L1. A driving voltage Vop applied to the lens <NUM> corresponds to the difference in voltage between the common terminal C0 and the individual electrode L1. Accordingly, if a voltage of the same level is applied with a time difference to the common terminal C0 and the individual electrode L1, it may be understood that the driving voltage Vop of <NUM> V is applied to the lens <NUM>. Referring to <FIG>, when the same voltage is applied through the common terminal C0, it may be understood that driving voltages Vop1 and Vop2 having pulse widths different from each other are applied to both terminals of the lens <NUM> according as a voltage applied to the individual electrode L1 has a time difference with the voltage applied to the common terminal C0.

In this case, an operating voltage output from the voltage booster <NUM> has a level of about <NUM> V. Therefore, elements included in the switching unit <NUM> need to be driven at a high voltage of a level of <NUM> V. The elements that should be driven at the high voltage have difficulty in being miniaturized. The elements that may be driven at the high voltage should satisfy characteristics of a breakdown voltage, specific on-resistance, a safe operating area (SOA), and a maximum forward voltage. If the elements operating at the high voltage are made excessively small, an element such as a transistor may not perform a function of switching or amplification. For these reasons, it is difficult to miniaturize a control circuit for supplying a driving voltage of the lens <NUM> and production cost may be raised due to low productivity.

<FIG> is a cross-sectional view of a camera module according to an embodiment.

The camera module illustrated in <FIG> may include a lens assembly <NUM>, a control circuit <NUM>, and an image sensor <NUM>.

The lens assembly <NUM> may include a plurality of lenses. The plural lenses may include a first lens, a focal length of which is adjusted in correspondence to a driving voltage applied between a common terminal and a plurality of individual electrodes.

The control circuit <NUM> may serve to supply the driving voltage to the first lens.

The image sensor <NUM> is aligned with the lens assembly <NUM> and may convert light transmitted through the lens assembly <NUM> into an electrical signal.

Referring to <FIG>, the camera module may include the plural circuits <NUM> and <NUM> and the lens assembly <NUM> including a plurality of lenses, which are formed on one printed circuit board (PCB), but this is purely exemplary and embodiments are not limited thereto. The construction of the control circuit <NUM> may be differently designed according to specifications required for the camera module. Particularly, if the magnitude of an operating voltage applied to the lens assembly <NUM> is reduced, the control circuit <NUM> may be implemented by a single chip. Then, the size of the camera module mounted in a portable device may be further reduced.

<FIG> is a cross-sectional view of the lens assembly <NUM> included in the camera module according to an embodiment.

The lens assembly <NUM> illustrated in <FIG> may include a first lens unit <NUM>, a second lens unit <NUM>, a liquid lens <NUM>, a lens housing <NUM>, and a connection terminal <NUM>. The structure of the lens assembly <NUM> illustrated in <FIG> is purely exemplary and may differ according to specifications required for the camera module. For example, in the illustrated example, the liquid lens unit <NUM> is located between the first lens unit <NUM> and the second lens unit <NUM>. However, as another example, the liquid lens unit <NUM> may be located on (in front of) the first lens unit <NUM>.

Referring to <FIG>, the first lens unit <NUM> is disposed at the front portion of the lens assembly and light is incident thereon from the exterior of the lens assembly. The first lens unit <NUM> may include at least one lens. Alternatively, the first lens unit <NUM> may include two or more lenses arranged based on a central axis PL to form an optical system.

The first lens unit <NUM> and second lens unit <NUM> may be mounted in the lens housing <NUM>. In this case, a through hole may be formed in the lens housing <NUM> and the first lens unit <NUM> and the second lens unit <NUM> may be arranged in the through hole. In addition, the liquid lens unit <NUM> may be inserted into a space between the first lens unit <NUM> and the second lens unit <NUM> arranged in the lens housing <NUM>.

Meanwhile, the first lens unit <NUM> may include an exposure lens <NUM>. The exposure lens <NUM> is extruded to the exterior of the lens housing <NUM> so that the exposure lens <NUM> may be externally exposed. Since the exposure lens <NUM> is exposed to the exterior, the surface thereof may be damaged. If the surface of the exposure lens <NUM> is damaged, the picture quality of an image captured by the camera module may be deteriorated. To prevent or suppress the surface of the exposure lens <NUM> from being damaged, a cover glass (not illustrated) may be disposed on the exposure lens <NUM> or a coating layer (not illustrated) may be formed on the exposure lens <NUM>. Alternatively, the exposure lens <NUM> may be formed of an abrasion-resistant material.

The second lens unit <NUM> may be disposed at the back side of the first lens unit <NUM> and the liquid lens unit <NUM> and light incident from the exterior to the first lens unit <NUM> may pass through the liquid lens unit <NUM> and then may be incident to the second lens unit <NUM>. The second lens unit <NUM> may be separated from the first lens unit <NUM> and may be disposed in the through hole formed in the lens housing <NUM>.

Meanwhile, the second lens unit <NUM> may include at least one lens. If the second lens unit <NUM> includes two or more lenses, the plural lenses may be arranged based on the central axis PL to form an optical system.

The liquid lens unit <NUM> may be disposed between the first lens unit <NUM> and the second lens unit <NUM> and may be inserted into an insertion hole <NUM> of the lens housing <NUM>. The liquid lens unit <NUM> may also be arranged based on the central axis PL, like the first lens unit <NUM> and the second lens unit <NUM>.

A lens region <NUM> may be included in the liquid lens unit <NUM>. The lens region <NUM> is a region to which light which has passed through the first lens unit <NUM> is transmitted and may include liquid in at least a part thereof. For example, the lens region <NUM> may include two types of liquids, i.e., a conductive liquid and a non-conductive liquid. The conductive liquid and the non-conductive liquid may not be mixed to form an interface. The interface of the conductive liquid and the nonconductive liquid may be modified by a driving voltage applied through the connection terminal <NUM>, so that the curvature and focal length of the liquid lens unit <NUM> may be changed. If the modification of the interface and change of the curvature of the liquid lens unit are controlled, the liquid lens unit <NUM>, and the lens assembly and the camera module including the liquid lens unit <NUM> may perform an optical zoom function, an AF function, and an OIS function, etc..

<FIG> illustrate a lens, a focal length of which is adjusted in correspondence to a driving voltage. Specifically, <FIG> illustrates a first lens <NUM> included in the lens assembly <NUM> (refer to <FIG> is an equivalent circuit of the lens <NUM>.

First, referring to <FIG>, the lens <NUM>, a focal length of which is adjusted according to a driving voltage, may receive an operating voltage through individual electrodes L1, L2, L3, and L4. The individual electrodes may have the same angular distance and may include four individual electrodes arranged in different directions. If the operating voltage is applied through the individual electrodes L1, L2, L3, and L4, an interface of a conductive liquid and a nonconductive liquid formed in the lens region <NUM> may be modified.

In addition, referring to <FIG>, the lens <NUM> may be regarded as a plurality of capacitors <NUM> each having one terminal configured to receive the operating voltage from the different individual electrodes L1, L2, L3, and L4 and the other terminal connected to a common terminal C0. Herein, each of the plural capacitors <NUM> included in the equivalent circuit may have small capacitance of a level of about <NUM> pico-Farad (pF).

<FIG> illustrates movement of an interface of a liquid lens. Specifically, <FIG> illustrate movements of interfaces 30a, 30b, 30c, and 30d which may occur when driving voltages are applied to individual electrodes L1, L2, L3, and L4 of the liquid lens <NUM>.

First, referring to <FIG>, if substantially the same driving voltages are applied to the individual electrodes L1, L2, L3, and L4 of the liquid lens <NUM>, an interface 30a may maintain a shape similar to a circle. In this case, since there is no substantial difference between each of the driving voltages applied to the first and third individual electrodes L1 and L3, respectively, and each of the driving voltages applied to the second and fourth individual electrodes L2 and L4, respectively, a distance LH between the first and third individual electrodes L1 and L3 is substantially the same as a distance LV between the second and forth individual electrodes L2 and L4 and movement of the interface 30a (e.g., a slant angle) may keep equilibrium.

Referring to <FIG>, the case is illustrated in which each of the driving voltages applied to the first and third individual electrodes L1 and L3 of the liquid lens <NUM>, respectively, is slightly lower than each of the driving voltages applied to the second and fourth individual electrodes L2 and L4, respectively. In this case, since force pulling or pushing the interface 30b may differ in a horizontal direction and a vertical direction, the length of the horizontal direction (i.e., the distance LH between the first and third individual electrodes L1 and L3) may be shorter than the distance of the vertical direction (i.e., the distance LV between the second and fourth individual electrodes L2 and L4). If each of the driving voltages applied to the second and fourth individual electrodes L2 and L4, respectively, is higher than each of the driving voltages applied to the first and third individual electrodes L1 and L3, respectively, since a slant angle of the interface 30b of the liquid lens <NUM> in the second and fourth individual electrodes L2 and L4 is higher than a slant angle of the interface 30b of the liquid lens <NUM> in the first and third individual electrodes L1 and L3, the length LV of the vertical direction is longer than the length LH in the horizontal direction although they appear to be same in the plane.

Referring to <FIG>, the case is illustrated in which the difference between the respective driving voltages applied to the first and third individual electrodes L1 and L3 of the liquid lens <NUM> and the respective driving voltages applied to the second and fourth individual electrodes L2 and L4 of the liquid lens <NUM> is large. In this case, since force pulling or pushing the interface 30c may greatly differ in the horizontal direction and the vertical direction, the outer shape, i.e., an edge, of the interface 30c may be curved or twisted. This phenomenon may result in distortion of the liquid lens <NUM>. When the respective driving voltages applied to the first and third individual electrodes L1 and L3 of the liquid lens <NUM> and the respective driving voltages applied to the second and fourth individual electrodes L2 and L4 of the liquid lens <NUM> are different to some degree, whether the liquid lens <NUM> is distorted and a distortion level of the liquid lens <NUM> may differ according to the structure and properties of the liquid lens <NUM>. For example, a slant of <NUM>° or more in a specific direction is compensated for by an OIS function, the interface 30c of the liquid lens <NUM> may be twisted. In this case, the difference between the length of the horizontal direction (i.e., the length LH between the first and third individual electrodes L1 and L3) and the length of the vertical direction (i.e., the distance LV between the second and fourth individual electrodes L2 and L4) may further increase compared with the case of the interface 30b described with reference to <FIG>.

Referring to <FIG>), when the driving voltages applied to the first and third individual electrodes L1 and L3 of the liquid lens <NUM> and the driving voltages applied to the second and fourth individual electrodes L2 and L4 of the liquid lens <NUM> differ by a preset level or more, the outer shape, i.e., the edge, of the interface 30d can be prevented from being curved or the interface 30d may be prevented from being twisted, by floating the first and third individual electrodes L1 and L3 in a state in which the driving voltages applied to the second and fourth individual electrodes L2 and L4 are maintained. Herein, floating state, which is well-known to the person skilled in the art, may mean an unknown state because the state is floated. The floating state may be formed by cutting off connecting a first voltage, a second voltage, and a ground voltage to a corresponding electrode. The floating state may be a state in which connection between a voltage source and a ground (reference voltage) is cut off. If a part of electrodes included in the liquid lens <NUM> is floated during a preset time or duration, force in a direction in which a corresponding electrode is located may be temporarily stopped. It may be difficult to clearly explain a potential difference of a floated electrode. However, in <FIG>, the interface 30d may induce natural balance of force through floating, unlike the case of <FIG> in which unbalance occurs by applying force to the interface 30c in a specific direction. Accordingly, even when the difference between the length of the horizontal direction (i.e., the distance LH between the first and third individual electrodes L1 and L3) and the length in the vertical direction (i.e., the distance LV between the second and fourth individual electrodes L2 and L4) is large, the liquid lens <NUM> may be prevented from being distorted.

<FIG> is a diagram for explaining a first driving method of a liquid lens according to an embodiment.

As illustrated, an interface of the liquid lens may be controlled by applying preset voltages (e.g., a ground voltage of <NUM> V and a high voltage of <NUM> V) to a plurality of individual electrodes L1, L2, L3, and L4 and a common electrode C0 of the liquid lens. In the present specification, the ground voltage may be a reference potential in a control circuit and a reference voltage of the control circuit.

Movement of the interface of the liquid lens may be controlled by potential differences between the individual electrodes and the common electrode. To apply a ground voltage of <NUM> V to one electrode of the liquid lens and a high voltage of <NUM> V to another electrode of the liquid lens, an operation of turning on a switch connected between the ground voltage <NUM> V and one electrode and on operation of turning on a switch capable of supplying the high voltage of <NUM> V output from a voltage booster in the control circuit to the other electrode may be performed.

<FIG> is a diagram for explaining a second driving method of a liquid lens according to an embodiment.

As illustrated, an interface of the liquid lens may be controlled by applying preset voltages (e.g., a ground voltage of <NUM> V and a high voltage of <NUM> V) to a plurality of individual electrodes L1, L2, L3, and L4 and a common electrode C0 of the liquid lens. Unlike <FIG>, some electrodes may be floated to control the interface of the liquid lens in <FIG>. For example, during the predetermined time, the high voltage of <NUM> V may be applied to one electrode of the liquid lens and the other electrode of the liquid lens may be maintained in a floated state, rather than applying the ground voltage of <NUM> V to the other electrode of the liquid lens.

Specifically, a timing chart of a case <NUM> in which the first individual electrode L1 is not floated may be compared with a timing chart of a case <NUM> in which the first individual electrode L1 is floated. If the first individual electrode L1 is floated, a floating voltage V may be a free state although it is difficult to clearly explain the floating voltage. For example, if the first individual electrode L1 is floated, the potential of the first individual electrode L1 may gradually decrease or may repeat rising and lowering. However, if the high voltage of <NUM> V is applied to the first individual electrode L1 in a free state and then the first individual electrode L1 enters a floating state, it may be assumed that the potential of the first individual electrode L1 will gradually decrease. If partial electrodes maintain a floating state that cannot be known and a driving voltage is applied to the other electrodes, a correction value increases as in <FIG> and, if the difference between driving voltages is big, natural balance of force may be induced.

<FIG> is a diagram illustrating a first embodiment of a control circuit. Herein, the control circuit is a circuit for applying an operating voltage to the lens <NUM> (refer to <FIG>) which is included in the lens assembly <NUM> and has a focal distance adjusted according to a driving voltage. Referring to the equivalent circuit of the lens <NUM>, the lens <NUM> may be regarded as including the plural capacitors <NUM> and the individual electrodes L1, L2, L3, and L4 for supplying the operating voltage to the respective capacitors <NUM> may be independently controlled. Hereinafter, for convenience of description, one capacitor <NUM> connected to one individual terminal will be explained by way of example to describe the control circuit.

The control circuit illustrated in <FIG> may include an individual electrode controller <NUM> and a common terminal controller <NUM>. The individual electrode controller <NUM> and the common terminal controller <NUM> may receive a ground voltage as a power voltage and receive an operating voltage having the magnitude of <NUM>/<NUM> of a driving voltage from a voltage booster <NUM>. The individual electrode controller <NUM> may supply the operating voltage to the individual electrode of the capacitor <NUM> in the form of a positive voltage and a negative voltage and the common terminal controller <NUM> may supply the operating voltage to the common terminal of the capacitor <NUM> in the form of the positive voltage and the negative voltage. The individual electrode controller <NUM> may supply the operating voltage to the individual electrode in the form of the positive voltage and the negative voltage when a ground voltage, a reference potential, or a reference voltage is regarded as <NUM> V, and the common terminal controller <NUM> may supply the operating voltage to the common electrode of the capacitor <NUM> in the form of the positive voltage and the negative voltage. The individual electrode controller <NUM> and the common terminal controller <NUM> may have substantially the same construction. Hereinafter, the individual electrode controller <NUM> will be described in more detail.

The individual electrode controller <NUM> may include a charge pump <NUM> for adjusting the operating voltage provided by a voltage booster <NUM> to a negative voltage. The individual electrode controller <NUM> may also include a switching unit including a plurality of switches. The switching unit may include a first switch <NUM> for selecting one of the ground voltage and the operating voltage, a second switch <NUM> for selecting one of an output of the charge pump <NUM> and the ground voltage, and a third switch <NUM> for selecting one of outputs of the first switch <NUM> and the second switch <NUM> and applying the selected output to the individual electrode of the capacitor <NUM>. Herein, each of the first switch <NUM>, the second switch <NUM>, and the third switch <NUM> may include at least one transistor. For example, each of the switches <NUM>, <NUM>, <NUM> may include two transistors.

Meanwhile, the first switch <NUM> and the second switch <NUM> in the individual electrode controller <NUM> may use the ground voltage as a bias voltage to determine the operating voltage applied to the individual electrode or the common electrode of the capacitor <NUM>.

The control circuit may further include the voltage booster <NUM> for converting a supply voltage Vin to the magnitude of the operating voltage. For example, the supply voltage input to the voltage booster <NUM> may have a level of <NUM> V to <NUM> V and the operating voltage output by the voltage booster <NUM> may have a level of <NUM> V to <NUM> V. Herein, the supply voltage input to the voltage booster <NUM> may be an operating voltage of a portable device in which a camera module is mounted.

Meanwhile, the individual electrode controller <NUM> and the common terminal controller <NUM> receive the ground voltage as the power voltage. Therefore, power consumption may be reduced as compared with the case in which the operating voltage, which is the output of the voltage booster <NUM>, is applied as the power voltage. For example, when it is unnecessary for the control circuit to operate, if the operating voltage, which is the output of the voltage booster <NUM>, is applied as the power voltage, the operating voltage is not transmitted to the capacitor <NUM> by the switches <NUM>, <NUM>, and <NUM>. However, since the operating voltage continues to be applied to the switches, power consumption may occur. It may be important to reduce power consumption in the camera module mounted in the portable device. Therefore, the output of the voltage booster <NUM> is not provided as the power voltage of the individual electrode controller <NUM> and the common terminal controller <NUM> and is connected to the switch <NUM>.

<FIG> illustrates a second embodiment of the control circuit.

As illustrated, the control circuit connected to a voltage booster <NUM> for receiving a supply voltage Vin and outputting an operating voltage may control a voltage applied to an individual electrode of a capacitor <NUM>.

The control circuit may include a first voltage stabilizer <NUM> for stabilizing the output of the voltage booster <NUM>. The output of the voltage booster <NUM> may be transmitted to a first charge pump <NUM>. The first charge pump <NUM> may include a first element for selectively transmitting a ground voltage, a second element for selectively transmitting an operating voltage, and a first capacitor located between the outputs of the first and second elements and a switching unit. Each of the first and second elements may include a transistor.

Meanwhile, a first switch <NUM> for selecting one of the ground voltage and the operating voltage may include a third element for selectively transmitting the ground voltage and a fourth element for selectively transmitting the operating voltage.

A second switch <NUM> for selecting one of the output of the first charge pump <NUM> and the ground voltage may include a fifth element for selectively transmitting the output of the first charge pump <NUM> and a sixth element for selectively transmitting the ground voltage. Thus, both the first switch <NUM> and the second switch <NUM> may selectively transmit the ground voltage. Since both the first switch <NUM> and the second switch <NUM> may transmit the ground voltage as the operating voltage applied to one terminal of the capacitor <NUM>, if one of the two switches transmits the operating voltage, the other may be connected to the ground voltage. Therefore, a positive voltage or a negative voltage of the operating voltage may be determined.

A third switch <NUM> for selecting one of the outputs of the first switch <NUM> and the second switch <NUM> and applying the selected output to the individual electrode of the capacitor <NUM> may include a seventh element for selectively transmitting the output of the first switch <NUM> and an eighth element for selectively transmitting the output of the second switch <NUM>.

The control circuit may include a common terminal controller <NUM>. The common terminal controller <NUM> may include a second voltage stabilizer <NUM>, a second charge pump <NUM>, a fourth switch <NUM>, a fifth switch <NUM>, and a sixth switch <NUM>. Herein, the second voltage stabilizer <NUM> may have the same construction as the first voltage stabilizer <NUM> and the second charge pump <NUM> may have the same construction as the first charge pump <NUM>. The fourth switch <NUM> may have the same construction as the first switch <NUM>, the fifth switch <NUM> may have the same construction as the second switch <NUM>, and the sixth switch <NUM> may have the same construction as the third switch <NUM>.

<FIG> is a cross-sectional diagram of a liquid lens according to an embodiment.

As illustrated, a liquid lens <NUM> may include a liquid, a first plate <NUM>, and electrodes. Liquids <NUM> and <NUM> included in the liquid lens <NUM> may include a conductive liquid and a nonconductive liquid. The first plate <NUM> may include a cavity <NUM> in which the conductive liquid and the nonconductive liquid are disposed. The cavity <NUM> may include a slanted surface. Electrodes <NUM> and <NUM> may be disposed on the first plate <NUM>. That is, the electrodes <NUM> and <NUM> may be disposed at the upper portion of the first plate <NUM> and the lower portion of the first plate <NUM>, respectively. The liquid lens <NUM> may further include a second plate <NUM> which may be disposed at the upper (or lower) portion of the electrodes <NUM> and <NUM>. The liquid lens <NUM> may further include a third plate <NUM> which may be disposed at the lower (or upper) portion of the electrodes <NUM> and <NUM>. As illustrated, an embodiment of the liquid lens <NUM> may include an interface <NUM> formed by the two different liquids <NUM> and <NUM>. An embodiment of the liquid lens <NUM> may include at least one or more substrates <NUM> and <NUM> for supplying a voltage to the liquid lens <NUM>. An edge of the liquid lens <NUM> may be thinner in thickness than the center of the liquid lens <NUM>.

The liquid lens <NUM> includes two different liquids, for example, the conductive liquid <NUM> and the nonconductive liquid <NUM>. The curvature and shape of the interface <NUM> formed by the two liquids may be adjusted by a driving voltage applied to the liquid lens <NUM>. The driving voltage supplied to the liquid lens <NUM> may be transmitted through the first substrate <NUM> and the second substrate <NUM>. The second substrate <NUM> may transmit four distinguishable individual driving voltages and the first substrate <NUM> may transmit one common voltage. Voltages supplied through the second substrate <NUM> and the first substrate <NUM> may be applied to the plural electrodes <NUM> and <NUM> exposed to each edge of the liquid lens <NUM>.

The liquid lens <NUM> may include the third plate <NUM> and the second plate <NUM> having a transparent material and the first plate <NUM> which is disposed between the third plate <NUM> and the second plate <NUM>. The first plate <NUM> may include an opening area having a slanted surface which is predetermined.

The liquid lens <NUM> may include the cavity <NUM> determined by the third plate <NUM>, the second plate <NUM>, and the opening area of the first plate <NUM>. Herein, the cavity <NUM> may be filled with the two liquids <NUM> and <NUM> having different properties (e.g., a conductive liquid and a nonconductive liquid) and the interface <NUM> may be formed between the two liquids <NUM> and <NUM> having different properties.

At least one of the two liquids <NUM> and <NUM> included in the liquid lens <NUM> is conductive. The liquid lens <NUM> may further include an insulation layer <NUM> disposed on the two electrodes <NUM> and <NUM> disposed on the upper portion and lower portion of the first plate <NUM> and on a slanted surface at which the conductive liquid may touch. The insulation layer <NUM> covers one electrode (e.g., the second electrode <NUM>) of the two electrodes <NUM> and <NUM> and exposes a part of the other electrode (e.g., the first electrode <NUM>) so that electrical energy may be applied to the conductive liquid (e.g., <NUM>). Herein, the first electrode <NUM> may include at least one electrode sector (e.g., C0) and the second electrode <NUM> may include two or more electrode sectors (e.g., L1, L2, L3, and L4 of <FIG>). For example, the second electrode <NUM> may include a plurality of electrode sectors which are sequentially disposed clockwise based on an optical axis. In the present specification, an electrode sector may be called a subelectrode.

One or more substrates <NUM> and <NUM> may be connected to transmit a driving voltage to the two electrodes <NUM> and <NUM> included in the liquid lens <NUM>. A focal length of the liquid lens <NUM> may be adjusted by changing the curvature and slant level of the interface <NUM> formed in the liquid lens according to the driving voltage.

<FIG> illustrates a third embodiment of the control circuit.

As illustrated, the control circuit may include a driving voltage output unit 230A for outputting a voltage of a preset magnitude having a polarity (positive polarity or negative polarity), a first switching unit <NUM> for selectively transmitting one of a voltage transmitted by the driving voltage output unit 230A and a ground voltage, and a second switching unit <NUM> for selectively transmitting a driving voltage transmitted by the first switching unit <NUM> to an electrode <NUM> of the liquid lens <NUM> (refer to <FIG>).

The driving voltage output unit 230A may include a first voltage generator for increasing the magnitude of a power voltage or a supply voltage to a preset magnitude and outputting a first voltage of the increased magnitude, and a charge pump <NUM> for receiving the first voltage from the first voltage generator <NUM>, changing the polarity of the first voltage, and outputting a second voltage having the changed polarity.

The first switching unit <NUM> may include a first switch <NUM> for selectively transmitting the first voltage transmitted by the first voltage generator <NUM> and a second switch <NUM> for selectively transmitting a first ground voltage. The first switching unit <NUM> may further include a fourth switch <NUM> for selectively transmitting the second voltage transmitted by the charge pump <NUM> and a fifth switch <NUM> for selectively transmitting a second ground voltage.

The first switching unit <NUM> may include two different input terminals and two different output terminals. The first ground voltage and the second ground voltage may be electrically connected to each other.

The second switching unit <NUM> may include a third switch <NUM> and a sixth switch <NUM>. The third switch <NUM> may selectively transmit one of the received first voltage and first ground voltage to the liquid lens electrode <NUM> and the sixth switch <NUM> may selectively transmit one of the received second voltage and second ground voltage to the liquid lens electrode <NUM>.

The first switching unit <NUM> may be commonly disposed in electrodes included in the liquid lens <NUM>. For example, the first switching unit <NUM> may be shared between a plurality of individual electrodes included in the liquid lens and the driving voltage may be transmitted to the plural individual electrodes through at least one first switching unit <NUM>.

On the other hand, the second switching unit <NUM> needs to be individually disposed in each electrode included in the liquid lens <NUM>. For example, the second switching unit <NUM> may be independently connected to each of the plural individual electrodes included in the liquid lens <NUM>, so that the second switching unit <NUM> may not be shared between the liquid lens electrodes <NUM>.

<FIG> illustrates a fourth embodiment of the control circuit.

As illustrated, the control circuit may include a voltage generator <NUM> for generating a voltage having a preset polarity and magnitude, a charge pump <NUM> for converting the polarity of a voltage generated by the voltage generator <NUM>, a plurality of switching elements 242a, 242b, 244a, 244b, 244c, 244d, 244e, 246a, 246b, 248a, and 248b for transmitting a driving voltage to a plurality of electrodes L1, L2, L3, L4, and C0 included in a liquid lens, and a plurality of second switching units 250a, 250b, 250c, 250d, and 250e for selectively transmitting voltages transmitted by the plural switching elements 242a, 242b, 244a, 244b, 244c, 244d, 244e, 246a, 246b, 248a, and 248b to the plural electrodes L1, L2, L3, L4, and C0 included in the liquid lens. Herein the plural switching elements 242a, 242b, 244a, 244b, 244c, 244d, 244e, 246a, 246b, 248a, and 248b may correspond to the first switching unit <NUM> described with reference to <FIG>.

Except for the three switch elements included in the charge pump <NUM>, the <NUM> switches elements, i.e., the first to sixth switches <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be connected to each liquid lens electrode <NUM> according to the control circuit described with reference to <FIG>. However, in the control circuit described with reference to <FIG>, partial switch elements disposed in the individual electrodes L1, L2, L3, and L4 among the plural electrodes L1, L2, L3, L4, and C0 included in the liquid lens are commonly connected, thereby reducing the number of switch elements. For example, when the liquid lens includes four individual electrodes and one common electrode, the control circuit described in <FIG> may include a total of <NUM> (= <NUM> x <NUM>) switching elements, whereas the control circuit described in <FIG> may include a total of <NUM> switching elements. That is, in <FIG>, a total sum of <NUM> switching elements 242a, 242b, 244a, 244b, 244c, 244d, 244e, 246a, 246b, 248a, and 248b and two switching elements included in each of five second switching units 250a, 250b, 250c, 250d, and 250e is <NUM>.

<FIG> illustrates a fifth embodiment of the control circuit.

As illustrated, the control circuit may include a voltage generator <NUM> for generating a voltage having a preset polarity and magnitude, a charge pump <NUM> for converting the polarity of the voltage generated by the voltage generator <NUM>, a plurality of switching elements 242a, 242b, 244a, 244b, 246a, 246b, 248a, and 248b for transmitting a driving voltage to a plurality of electrodes L1, L2, L3, L4, and C0 included in a liquid lens, and a plurality of second switching units 250a, 250b, 250c, 250d, 250e for selectively transmitting voltages transmitted by the plural switching elements 242a, 242b, 244a, 244b, 246a, 246b, 248a, and 248b to the plural electrodes L1, L2, L3, L4, and C0 included in the liquid lens. Herein, the plural switching elements 242a, 242b, 244a, 244b, 246a, 246b, 248a, and 248b may correspond to the first switching unit <NUM> described with reference to <FIG>.

Except for three switch elements included in the charge pump <NUM>, when the liquid lens includes four individual electrodes and one common electrode, the control circuit described in <FIG> may include <NUM> switching elements, whereas the control circuit described in <FIG> may include <NUM> switching elements. Switching elements for selectively transmitting a ground voltage to each individual electrode included in the liquid lens may be connected commonly without being individually disposed, so that the number of switching elements included in the control circuit may be further reduced as illustrated in <FIG>. If the number of switching elements is reduced, the total size of the control circuit may be reduced and power consumption may be decreased.

Referring to <FIG>, the number of the plural switching elements 242a, 242b, 244a, 244b, 246a, 246b, 248a, and 248b corresponding to the first switching unit <NUM> described in <FIG> may be fixed regardless of the number of electrodes included in the liquid lens. For example, irrespective of whether <NUM>, <NUM>, <NUM>, or <NUM> individual electrodes are included in the liquid lens, the first switching unit <NUM> shown in <FIG> may be implemented only by <NUM> switching elements. On the other hand, the number of switching elements included in the plural second switching units 250a, 250b, 250c, 250d, and 250e may be the number of electrodes included in the liquid lens, i.e., the sum of the number of individual electrodes and the number of common electrodes. In other words, the number of switching elements included in the plural second switching units 250a, 250b, 250c, 250d, and 250e may be twice the sum of the number of individual electrodes and the number of common electrodes included in the liquid lens. For example, if four individual electrodes and one common electrode are included in the liquid lens, the number of electrodes is <NUM> and the number of switching elements included in the plural second switching units may be <NUM>.

If <NUM> individual electrodes and one common electrode are included in the liquid lens, the number of electrodes is <NUM> and the number of switching elements included in the plural second switching units may be <NUM>.

According to an embodiment, even when the number of electrodes included in the liquid lens varies, the number of switching elements included in the driving voltage control circuit may be fixed.

<FIG> is a diagram illustrating a first operation example according to an embodiment of the control circuit illustrated in <FIG>.

The liquid lens <NUM> (refer to <FIG> and <FIG>) includes four individual electrodes L1, L2, L3, and L4 and one common electrode C0 and it is assumed that the first individual electrode L1 and the third individual electrode L3 are symmetrically arranged based on the center of the liquid lens <NUM> and the second individual electrode L2 and the fourth individual electrode L4 are symmetrically arranged based on the center of the liquid lens <NUM>. Hereinafter, for convenience of description, description will be given focusing on driving voltages applied to the first individual electrode L1, the second individual electrode L2, and the common electrode C0. Particularly, the case in which a positive voltage is applied to the common electrode C0 in <FIG> is explained.

If the first individual electrode L1 and the third individual electrode L3 are symmetrically arranged based on the center of the liquid lens <NUM> and the second individual electrode L2 and the fourth individual electrode L4 are symmetrically arranged based on the center of the liquid lens <NUM>, the same driving voltages may be applied to the first individual electrode L1 and the third individual electrode L3 and the same driving voltages may be applied to the second individual electrode L2 and the fourth individual electrode L4. According to an embodiment, different driving voltages may be applied to the first individual electrode L1, the second individual electrode L2, the third individual electrode L3, and the fourth individual electrode L4. For example, the driving voltages symmetrical to or different from the driving voltages applied to the first and second individual electrodes L1 and L2 may be applied at the same time t to the third and fourth individual electrodes L3 and L4. That is, at the same time t, a driving voltage having the same level as or a different level from a driving voltage applied to the first individual electrode L1 may be applied to the third individual electrode L3 and a driving voltage having the same level as or a different level from a driving voltage applied to the second individual electrode L2 may be applied to the fourth individual electrode L4.

Referring to the timing chart illustrated in <FIG>, a plurality of operating modes ①, ②, ③, ④, ⑤, and ⑥ may be present according to timings at which the driving voltage is applied to the first individual electrode L1, the second individual electrode L2, and the common electrode C0. In the first mode ①, a ground voltage is applied to all of the common electrode C0, the second individual electrode L2, and the first individual electrode L1. In the second mode ②, a positive voltage generated by the voltage generator <NUM> is applied to the common electrode C0 and the ground voltage is applied to each of the first individual electrode L1 and the second individual electrode L2. In the third mode ③, the positive voltage generated by the voltage generator <NUM> is applied to the common electrode C0 and a negative voltage transmitted by the charge pump is applied to each of the first individual electrode L1 and the second individual electrode L2. In the fourth mode ④, the first individual electrode L1 is floated and the second individual electrode L2 and the common electrode C0 are not floated. Then, in the fourth mode ④, the positive voltage generated by the voltage generator <NUM> is applied to the common electrode C0 and the negative voltage is applied to the second individual electrode L2, whereas the first individual electrode L1 is floated. Referring to the timing chart, although, in the fourth mode ④, the level of a voltage applied to the floated first individual electrode L1 is gradually raised, the voltage of the floated first individual electrode L1 may have a level which is difficult to predict. On the other hand, a potential difference between the second individual electrode L2 and the common electrode C0 which are not floated may be clear. In this way, although it is difficult to clearly explain the potential difference between the first individual electrode L1 and the common electrode C0, movement of charges may be naturally performed in a floated state as compared with artificial control of movement of charges. If movement of charges is naturally performed, the potential difference between the first individual electrode L1 and the common electrode C0 may be gradually reduced as illustrated in the timing chart. In the fifth mode ⑤, the ground voltage is applied to the common electrode C0 and the first individual electrode L1 is still floated, whereas the negative voltage transmitted by the charge pump is applied to the second individual electrode L2. In the sixth mode ⑥, the ground voltage is applied to all of the common electrode C0, the first individual electrode L1, and the second individual electrode L2.

In the first to sixth modes ①, ②, ③, ④, ⑤, and ⑥, movement of an interface <NUM> included in the liquid lens <NUM> may be determined by the magnitude of a driving voltage Vop applied between the common electrode C0 and the first individual electrode L1 or between the common electrode C0 and the second individual electrode L2. In this case, movement of the interface <NUM> may be controlled by an absolute value of the magnitude of the driving voltage Vop regardless of the polarity of the driving voltage Vop. For example, if the first individual electrode L1 and the third individual electrode L3 are floated and the second individual electrode L2 and the fourth individual electrode L4 maintain a constant potential difference (i.e., the driving voltage), more natural movement of the interface <NUM> may be implemented as described in <FIG> and damping which may occur due to a potential difference between individual electrodes may be reduced.

In the first to sixth modes ①, ②, ③, ④, ⑤, and ⑥, the driving voltage applied to the first individual electrode L1 and the common electrode C0 may be determined by ON/OFF of a plurality of switch elements included in the control circuit. When the ground voltage, the positive voltage, or the negative voltage is applied to the first individual electrode L1, the second individual electrode L2, and the common electrode C0, which path and which switch element are used are denoted by dotted lines and arrows as illustrated in <FIG>.

Paths denoted by dotted lines and arrows in the circuit of <FIG> are purely exemplary and various combinations of different paths may be used to transmit the driving voltage to the first individual electrode L1, the second individual electrode L2, and the common electrode C0 according to an embodiment.

<FIG> is a diagram illustrating a second operation example according to an embodiment of the control circuit illustrated in <FIG>.

The liquid lens <NUM> (refer to <FIG> and <FIG>) includes four individual electrodes L1, L2, L3, and L4 and one common electrode C0 and it is assumed that the first individual electrode L1 and the third individual electrode L3 are symmetrically arranged based on the center of the liquid lens <NUM> and the second individual electrode L2 and the fourth individual electrode L4 are symmetrically arranged based on the center of the liquid lens <NUM>. Hereinafter, for convenience of description, description will be given focusing on a driving voltage applied to the first individual electrode L1, the second individual electrode L2, and the common electrode C0. Particularly, the case in which a negative voltage is applied to the common electrode C0 in <FIG> is explained.

If the first individual electrode L1 and the third individual electrode L3 are symmetrically arranged based on the center of the liquid lens <NUM> and the second individual electrode L2 and the fourth individual electrode L4 are symmetrically arranged based on the center of the liquid lens <NUM>, the same driving voltage may be applied to the first individual electrode L1 and the third individual electrode L3 and the same driving voltage may be applied to the second individual electrode L2 and the fourth individual electrode L4. According to an embodiment, different driving voltages may be applied to the first individual electrode L1, the second individual electrode L2, the third individual electrode L3, and the fourth individual electrode L4. For example, driving voltages symmetrical to or different from driving voltages applied to the first and second individual electrodes L1 and L2 may be applied at the same time t to the third and fourth individual electrodes L3 and L4. That is, at the same time t, a driving voltage having the same level as or a different level from a driving voltage applied to the first individual electrode L1 may be applied to the third individual electrode L3 and a driving voltage having the same level as or a different level from a driving voltage applied to the second individual electrode L2 may be applied to the fourth individual electrode L4.

Referring to the timing chart illustrated in <FIG>, a plurality of operating modes ①, ②, ③, ④, ⑤, and ⑥ may be present according to timings at which the driving voltage is applied to the first individual electrode L1, the second individual electrode L2, and the common electrode C0. In the first mode ①, a ground voltage is applied to all of the common electrode C0, the second individual electrode L2, and the first individual electrode L1. In the second mode ②, a negative voltage transmitted by the charge pump which converts a positive voltage generated by the voltage generator <NUM> into the negative voltage is applied to the common electrode C0 and the ground voltage is applied to the first individual electrode L1 and the second individual electrode L2. In the third mode ③, the negative voltage transmitted by the charge pump is applied to the common electrode C0 and the positive voltage generated by the voltage generator <NUM> is applied to the first individual electrode L1 and the second individual electrode L2. In the fourth mode ④, the first individual electrode L1 is floated and the second individual electrode L2 and the common electrode C0 are not floated. Then, in the fourth mode ④, the negative voltage is applied to the common electrode C0 and the positive voltage is applied to the second individual electrode L2, whereas the first individual electrode L1 is floated. Referring to the timing chart, although, in the fourth mode ④, the level of a voltage applied to the floated first individual electrode L1 gradually lowered, the voltage of the floated first individual electrode L1 may have a level which is difficult to predict. Accordingly, a potential difference between the second individual electrode L2 and the common electrode C0, which are not floated, may be clear. Meanwhile, although it is difficult to clearly explain the potential difference between the first individual electrode L1 and the common electrode C0, movement of charges may be naturally performed in a floated state as compared with artificial control of movement of charges. If movement of charges is naturally performed, the potential difference between the first individual electrode L1 and the common electrode C0 may be gradually reduced as illustrated in the timing chart. In the fifth mode ⑤, the ground voltage is applied to the common electrode C0 and the first individual electrode L1 is floated, whereas the positive voltage generated by the voltage generator <NUM> is applied to the second individual electrode L2. In the sixth mode ⑥, the ground voltage is applied to all of the common electrode C0, the first individual electrode L1, and the second individual electrode L2.

In the first to sixth modes ①, ②, ③, ④, ⑤, and ⑥, the driving voltages applied to the first individual electrode L1 and the common electrode C0 may be determined by ON/OFF of a plurality of switch elements included in the control circuit. When the ground voltage, the positive voltage, or the negative voltage is applied to the first individual electrode L1, the second individual electrode L2, and the common electrode C0, which path and which switch element are used are denoted by dotted lines and arrows as illustrated in <FIG>.

Referring to <FIG> and <FIG>, a driving voltage having a magnitude which is twice the magnitude of a voltage applied to an electrode may be applied to the liquid lens by applying voltages having opposite polarities to the first individual electrode L1 and the common electrode C0 or applying voltages having opposite polarities to the second individual electrode L2 and the common electrode C0. For example, when a driving voltage of about <NUM> V is needed to control movement of the interface included in the liquid lens, if voltages of about <NUM> V having different polarities are applied to the first individual electrode L1 and the common electrode C0, substantially the same effect as applying a driving voltage of about <NUM> V may be obtained. A switching element for selectively transmitting a lower voltage may be reduced in size. Then, the control circuit may be miniaturized and integration thereof may be raised.

<FIG> is a diagram illustrating a sixth embodiment of the control circuit.

The control circuit illustrated in <FIG> may include a driving voltage output unit 230B for outputting a plurality of voltages of a preset magnitude having a polarity (positive polarity or negative polarity), a first switching unit <NUM> for selectively transmitting one of a voltage transmitted by the driving voltage output unit 230B and a ground voltage, and a second switching unit <NUM> for selectively transmitting a driving voltage transmitted by the first switching unit <NUM> to a liquid lens electrode <NUM>. The liquid lens electrode <NUM> may be one of the plural electrodes <NUM> and <NUM> included in the liquid lens <NUM> (refer to <FIG>).

The driving voltage output unit 230B may include a first voltage generator <NUM> for generating a first voltage of a preset increased size based on a power voltage or a supply voltage and a second voltage generator <NUM> for generating a second voltage having a preset increased size based on the power voltage ot the supply voltage and generating the second voltage having an opposite polarity to the first voltage. As compared with the control circuit described in <FIG>, the driving voltage output unit 230B may include the second voltage generator <NUM> capable of individually generating the second voltage instead of using the charge pump <NUM>.

The first switching unit <NUM> may include a first switch <NUM> for selectively transmitting the first voltage transmitted by the first voltage generator <NUM> and a second switch <NUM> for selectively transmitting a first ground voltage. The first switching unit <NUM> may further include a fourth switch <NUM> for selectively transmitting a second voltage transmitted by the charge pump <NUM> and a fifth switch <NUM> for selectively transmitting a second ground voltage.

The first switching unit <NUM> may include two different input terminals and two different output terminals. The first ground voltage and the second ground voltage may be electrically connected.

The second switching unit <NUM> may include a third switch <NUM> for selectively transmitting one of the received first voltage and first ground voltage to the liquid lens electrode <NUM> and a sixth switch <NUM> for selectively transmitting one of the received second voltage and second ground voltage to the liquid lens electrode <NUM>.

The first switching unit <NUM> may be commonly disposed in electrodes included in the liquid lens <NUM>. For example, the first switching unit <NUM> may be shared between a plurality of individual electrodes included in the liquid lens so that a driving voltage may be transmitted to the plural individual electrodes through at least one first switching unit <NUM>.

<FIG> illustrates a seventh embodiment of the control circuit.

The control circuit illustrated in <FIG> may include a first voltage generator <NUM> for generating a voltage having a preset polarity and magnitude, a second voltage generator <NUM> for generating a voltage having an opposite polarity to the voltage generated from the first voltage generator <NUM> independently of the first voltage generator <NUM>, a plurality of switching elements 242a, 242b, 244a, 244b, 244c, 244d, 244e, 246a, 246b, 248a, and 248b for transmitting a driving voltage to a plurality of electrodes L1, L2, L3, L4, and C0 included in a liquid lens, and a plurality of second switching units 250a, 250b, 250c, 250d, and 250e for selectively transmitting voltages transmitted by the plural switching elements 242a, 242b, 244a, 244b, 244c, 244d, 244e, 246a, 246b, 248a, and 248b to the plural electrodes L1, L2, L3, L4, and C0 included in the liquid lens. Herein the plural switching elements 242a, 242b, 244a, 244b, 244c, 244d, 244e, 246a, 246b, 248a, and 248b may correspond to the first switching unit <NUM> described with reference to <FIG>.

According to the control circuit described in <FIG>, <FIG> switching elements may be connected to the liquid lens electrode <NUM>. However, in the control circuit described in <FIG>, partial switch elements disposed in the individual electrodes L1, L2, L3, and L4 among the plural electrodes L1, L2, L3, L4, and C0 included in the liquid lens are commonly connected, thereby reducing the number of switch elements. For example, when the liquid lens includes four individual electrodes and one common electrode, the control circuit described in <FIG> may include a total of <NUM> (= <NUM> x <NUM>) switching elements, whereas the control circuit described in <FIG> may include a total of <NUM> switching elements.

<FIG> illustrates an eighth embodiment of the control circuit.

The control circuit illustrated in <FIG> may include a first voltage generator <NUM> for generating a voltage having a preset polarity and magnitude, a second voltage generator <NUM> for generating a voltage having an opposite polarity to the voltage generated from the first voltage generator <NUM> independently of the first voltage generator <NUM>, a plurality of switching elements 242a, 242b, 244a, 244b, 246a, 246b, 248a, and 248b for transmitting a driving voltage to a plurality of electrodes L1, L2, L3, L4, and C0 included in a liquid lens, and a plurality of second switching units 250a, 250b, 250c, 250d, 250e for selectively transmitting voltages transmitted by the plural switching elements 242a, 242b, 244a, 244b, 246a, 246b, 248a, and 248b to the plural electrodes L1, L2, L3, L4, and C0 included in the liquid lens. Herein, the plural switching elements 242a, 242b, 244a, 244b, 246a, 246b, 248a, and 248b may correspond to the first switching unit <NUM> described with reference to <FIG>.

When the liquid lens includes four individual electrodes and one common electrode, the control circuit described in <FIG> includes <NUM> switching elements, whereas the control circuit described in <FIG> may include <NUM> switching elements. Switching elements for selectively transmitting a ground voltage to each individual electrode included in the liquid lens may be connected commonly without being individually disposed, so that the number of switching elements included in the control circuit may further be reduced as illustrated in <FIG>. If the number of switching elements is reduced, the total size of the control circuit may be reduced and power consumption may be decreased.

Referring to <FIG>, the number of the plural switching elements 242a, 242b, 244a, 244b, 246a, 246b, 248a, and 248b corresponding to the first switching unit <NUM> described in <FIG> may be fixed regardless of the number of electrodes included in the liquid lens. For example, irrespective of whether <NUM>, <NUM>, <NUM>, or <NUM> individual electrodes are included in the liquid lens, the first switching unit <NUM> described in <FIG> may be implemented only by <NUM> switching elements. On the other hand, the number of switching elements included in the plural second switching units 250a, 250b, 250c, 250d, and 250e may correspond to the number of electrodes included in the liquid lens, i.e., the sum of the number of individual electrodes and the number of common electrodes. In other words, the number of switching elements included in the plural second switching units 250a, 250b, 250c, 250d, and 250e may be twice the sum of the number of individual electrodes and the number of common electrodes included in the liquid lens. For example, if there are four individual electrodes and one common electrode included in the liquid lens, the number of electrodes is <NUM> and the number of switching elements included in the plural second switching units may be <NUM>.

If the number of individual electrodes included in the liquid lens is <NUM> and the number of common electrodes included in the liquid lens is <NUM>, the number of electrodes is <NUM> and the number of switching elements included in the plural second switching units may be <NUM>. According to an embodiment, even when the number of electrodes included in the liquid lens varies, the number of switching elements included in the driving voltage control circuit may be fixed.

<FIG> illustrates a first operation example according to an embodiment of the control circuit illustrated in <FIG>. The liquid lens <NUM> (refer to <FIG> and <FIG>) includes four individual electrodes L1, L2, L3, and L4 and one common electrode C0 and it is assumed that the first individual electrode L1 and the third individual electrode L3 are symmetrically arranged based on the center of the liquid lens <NUM> and the second individual electrode L2 and the fourth individual electrode L4 are symmetrically arranged based on the center of the liquid lens <NUM>. Hereinafter, for convenience of description, description will be given focusing on driving voltages applied to the first individual electrode L1, the second individual electrode L2, and the common electrode C0. Particularly, the case in which a positive voltage is applied to the common electrode C0 in <FIG> is explained.

If the first individual electrode L1 and the third individual electrode L3 are symmetrically arranged based on the center of the liquid lens <NUM> and the second individual electrode L2 and the fourth individual electrode L4 are symmetrically arranged based on the center of the liquid lens <NUM>, the same driving voltages may be applied to the first individual electrode L1 and the third individual electrode L3 and the same driving voltages may be applied to the second individual electrode L2 and the fourth individual electrode L4. According to an embodiment, different driving voltages may be applied to the first individual electrode L1, the second individual electrode L2, the third individual electrode L3, and the fourth individual electrode L4. For example, driving voltages symmetrical to or different from driving voltages applied to the first and second individual electrodes L1 and L2 may be applied at the same time t to the third and fourth individual electrodes L3 and L4. That is, at the same time t, a driving voltage having the same level as or a different level from a driving voltage applied to the first individual electrode L1 may be applied to the third individual electrode L3 and a driving voltage having the same level as or a different level from a driving voltage applied to the second individual electrode L2 may be applied to the fourth individual electrode L4.

Referring to the timing chart illustrated in <FIG>, a plurality of operating modes ①, ②, ③, ④, ⑤, and ⑥ may be present according to timings at which the driving voltage is applied to the first individual electrode L1, the second individual electrode L2, and the common electrode C0. In the first mode ①, a ground voltage is applied to all of the common electrode C0, the second individual electrode L2, and the first individual electrode L1. In the second mode ②, a positive voltage generated by the first voltage generator <NUM> is applied to the common electrode C0 and the ground voltage is applied to each of the first individual electrode L1 and the second individual electrode L2. In the third mode ③, the positive voltage generated by the first voltage generator <NUM> is applied to the common electrode C0 and a negative voltage transmitted by the second voltage generator <NUM> is applied to each of the first individual electrode L1 and the second individual electrode L2. In the fourth mode ④, the first individual electrode L1 is floated and the second individual electrode L2 and the common electrode C0 are not floated. That is, in the fourth mode ④, the positive voltage is applied to the common electrode C0 and the negative voltage is applied to the second individual electrode L2, whereas the first individual electrode L1 is floated.

Referring to the timing chart illustrated in <FIG>, although, in the fourth mode ④, an absolute value of the level of the voltage applied to the floated first individual electrode L1 is gradually lowered, the voltage of the floated first individual electrode L1 may have a level which is difficult to predict. Accordingly, a potential difference between the second individual electrode L2 and the common electrode C0, which are not floated, may be clear. Meanwhile, although it is difficult to clearly explain a potential difference between the first individual electrode L1 and the common electrode C0, movement of charges may be naturally performed in a floated state as compared with artificial control of movement of charges. If movement of charges is naturally performed, the potential difference between the first individual electrode L1 and the common electrode C0 may be gradually reduced as illustrated in the timing chart. In the fifth mode ⑤, the ground voltage is applied to the common electrode C0 and the first individual electrode L1 is floated, whereas the negative voltage transmitted by the second voltage generator <NUM> is applied to the second individual electrode L2. In the sixth mode ⑥, the ground voltage is applied to all of the common electrode C0, the first individual electrode L1, and the second individual electrode L2.

Paths denoted by dotted lines and arrows in the circuit of <FIG> are purely exemplary and various combinations of different paths may be used to transmit the driving voltage to the first individual electrode L1 and the common electrode C0 according to an embodiment.

<FIG> illustrates a second operation example according to an embodiment of the control circuit illustrated in <FIG>.

If the first individual electrode L1 and the third individual electrode L3 are symmetrically arranged based on the center of the liquid lens <NUM> and the second individual electrode L2 and the fourth individual electrode L4 are symmetrically arranged based on the center of the liquid lens <NUM>, the same driving voltage may be applied to the first individual electrode L1 and the third individual electrode L3 and the same driving voltage may be applied to the second individual electrode L2 and the fourth individual electrode L4. According to an embodiment, different driving voltages may be applied to the first individual electrode L1, the second individual electrode L2, the third individual electrode L3, and the fourth individual electrode L4. For example, a driving voltage symmetrical to or different from a driving voltage applied to the first and second individual electrodes L1 and L2 may be applied at the same time t to the third and fourth individual electrodes L3 and L4. That is, at the same time t, a driving voltage having the same level as or a different level from a driving voltage applied to the first individual electrode L1 may be applied to the third individual electrode L3 and a driving voltage having the same level as or a different level from a driving voltage applied to the second individual electrode L2 may be applied to the fourth individual electrode L4.

Referring to the timing chart illustrated in <FIG>, a plurality of operating modes ①, ②, ③, ④, ⑤, and ⑥ may be present according to timings at which the driving voltage is applied to the first individual electrode L1, the second individual electrode L2, and the common electrode C0. In the first mode ①, a ground voltage is applied to all of the common electrode C0, the second individual electrode L2, and the first individual electrode L1. In the second mode ②, a negative voltage transmitted by the second voltage generator <NUM> is applied to the common electrode C0 and the ground voltage is applied to each of the first individual electrode L1 and the second individual electrode L2. In the third mode ③, the negative voltage generated by second voltage generator <NUM> is applied to the common electrode C0 and the positive voltage generated by the first voltage generator <NUM> is applied to each of the first individual electrode L1 and the second individual electrode L2. In the fourth mode ④, the first individual electrode L1 is floated and the second individual electrode L2 and the common electrode C0 are not floated. That is, in the fourth mode ④, the negative voltage is applied to the common electrode C0 and the positive voltage is applied to the second individual electrode L2, whereas the first individual electrode L1 is floated. Referring to the timing chart, although the level of a voltage applied to the floated first individual electrode L1 in the fourth mode ④ is gradually lowered, the voltage of the floated first individual electrode L1 may have a level which is difficult to predict. Accordingly, a potential difference between the second individual electrode L2 and the common electrode C0 which are not floated may be clear. Meanwhile, although it is difficult to clearly explain the potential difference between the first individual electrode L1 and the common electrode C0, movement of charges may be naturally performed in a floated state as compared with artificial control of movement of charges. If movement of charges is naturally performed, the potential difference between the first individual electrode L1 and the common electrode C0 may be gradually reduced as illustrated in the timing chart. In the fifth mode ⑤, the ground voltage is applied to the common electrode C0 and the first individual electrode L1 is floated, whereas the positive voltage generated by the voltage generator <NUM> is applied to the second individual electrode L2. In the sixth mode ⑥, the ground voltage is applied to all of the common electrode C0, the first individual electrode L1, and the second individual electrode L2.

Paths denoted by dotted lines and arrows in the circuit of <FIG> are purely exemplary and various combinations of different paths may be used to transmit the driving voltage to the first individual electrode L1 and the common electrode C0, according to the embodiment.

Referring to <FIG> and <FIG>, a driving voltage having a magnitude which is twice the magnitude of a voltage applied to an electrode may be applied to the liquid lens by applying voltages having opposite polarities to the first individual electrode L1 and the common electrode C0. Then, when a driving voltage of about <NUM> V is needed to control movement of the interface included in the liquid lens, if voltages of about <NUM> V having different polarities are applied to the first individual electrode L1 and the common electrode C0, substantially the same effect as applying a driving voltage of about <NUM> V may be obtained. A switching element for selectively transmitting a lower voltage may be reduced in size. Then, the control circuit may be miniaturized and integration thereof may be raised.

The above-described liquid lens may be included in a camera module. The camera module may include a lens assembly including a liquid lens mounted in a housing and at least one solid lens disposed in front of or behind the liquid lens, an image sensor for converting an optical signal transmitted through the lens assembly to an electrical signal, and a control circuit for supplying a driving voltage to the liquid lens.

A camera module according to an embodiment may include a liquid lens including a common electrode and a plurality of individual electrodes; and a control circuit connected electrically to the common electrode and the individual electrodes and configured to control the liquid lens, wherein, when a driving voltage for driving the liquid lens is changed, the control circuit floats at least one of the plural individual electrodes in a state in which a first voltage is applied to the common electrode.

The control circuit may apply a second voltage to the at least one individual electrode after floating the at least one individual electrode.

The control circuit may include a voltage generator configured to generate a voltage; a first switching unit configured to selectively switch the voltage generated from the voltage generator or a ground voltage; and a second switching unit configured to switch a voltage output from the first switching unit ON or OFF.

The voltage generator may include a first voltage generator; and a second voltage generator, wherein a voltage output from the first voltage generator is different from a voltage output from the second voltage generator.

The second switching unit may include a first switch configured to switch the voltage output from the first switching unit ON or OFF; and a second switch configured to switch the voltage output from the second voltage generator ON or OFF.

The floating may be a state in which the first switch and the second switch are simultaneously switched OFF.

The control circuit may float the individual electrode when driving voltages applied to at least two individual electrodes among the plural individual electrodes are different.

The first voltage and the second voltage may be the same voltage.

The driving voltage may be a root mean square voltage of a voltage applied between the common electrode and the individual electrodes.

A camera module according to an embodiment may include a liquid lens including a common electrode and a plurality of individual electrodes; and a control circuit connected electrically to the common electrode and the plural individual electrodes and configured to control the liquid lens, wherein the control circuit may include a voltage generator configured to generate a voltage; a first switching element disposed between the voltage generator and the individual electrodes; and a second switching unit disposed between the first switching unit and the individual electrodes, and wherein, when a driving voltage applied to the liquid lens is changed, the control circuit may switch the second switching unit OFF during a preset time.

The voltage generator may include a first voltage generator; and a second voltage generator, wherein a voltage output from the first voltage generator is different from a voltage output from the second voltage generator, and wherein the second switching unit may include a first switch disposed between the first switching unit and the individual electrodes; and a second switch disposed between the second voltage generator and the individual electrodes.

The switching of the second switching unit OFF during the preset time may be a state in which the first switch and the second switch are simultaneously switched OFF.

Change of the driving voltage may be made from a low driving voltage to a high driving voltage.

The plural individual electrodes may include first to fourth individual electrodes disposed sequentially in a circumferential direction, and when a driving voltage applied to the first individual electrode is different from a driving voltage applied to the third individual electrode, at least one of the plural individual electrodes may be floated.

A method of controlling a liquid lens including a common electrode and a plurality of individual electrodes according to an embodiment may include, when a driving voltage applied to the liquid lens is changed, floating at least one of the plural individual electrodes during a preset time in a state in which a voltage is applied to the common electrode; and reapplying a voltage to the at least one individual electrode after floating the at least one individual electrode.

The floating may include floating at least one of two individual electrodes when driving voltages applied to the two individual electrodes among the plural individual electrodes are different.

The voltage may be a first voltage, a second voltage, or a ground voltage.

The liquid lens may include a first plate in which a cavity for accommodating a conductive liquid and a nonconductive liquid are formed; the common electrode disposed on the first plate; the plural individual electrodes disposed under the first plate; a second plate disposed on the common electrode; and a third plate disposed under the first plate.

Although only several embodiments have been described above with regard to embodiments, various other embodiments are possible. The technical contents of the above-described embodiments may be combined in various forms unless they are incompatible and, thus, may be implemented in new embodiments.

An optical device (or optical instrument) including the above-described camera module may be implemented. The optical device may include a device capable of processing or analyzing an optical signal. Examples of the optical device may include a camera/video device, a telescope, a microscope, an interferometer, a photometer, a polarimeter, a spectrometer, a reflectometer, an autocollimator, a lensmeter, etc. and the embodiments of the present invention may be applied to an optical device including a liquid lens. The optical device may also be implemented by a portable device such as a smartphone, a notebook computer, or a tablet computer. Such an optical device may include a camera module, a display unit for outputting an image, and a body housing in which the camera module and the display unit are mounted. The optical device may further include a communication module which is mounted in the body housing and communicates with other devices and a memory unit for storing data. The method according to the above-described embodiments may be implemented as a computer-executable program that can be recorded in a computer-readable medium. Examples of the computer-readable medium include a read only memory (ROM), a random access memory (RAM), a compact disc (CD)-ROM, a magnetic tape, a floppy disk, and an optical data storage.

The computer-readable recording medium can be distributed over a computer system connected to a network so that computer-readable code is written thereto and executed therefrom in a decentralized manner. Functional programs, code, and code segments needed to realize the above-described method can be easily derived by programmers skilled in the art.

Various embodiments have been described in the best mode for carrying out the invention.

Claim 1:
A camera module, comprising:
a liquid lens including a common electrode (C0) and a plurality of individual electrodes (L1, L2, L3, L4); and
a control circuit connected electrically to the common electrode (C0) and the individual electrodes (L1, L2, L3, L4) and configured to control the liquid lens,
wherein, when a driving voltage for driving the liquid lens is changed, the control circuit floats at least one of the plural individual electrodes (L1, L2, L3, L4) in a state in which a first voltage is applied to the common electrode (C0), and
wherein the control circuit comprises:
a voltage generator (<NUM>) configured to generate a voltage;
a first switching unit (<NUM>) configured to selectively switch the voltage generated from the voltage generator (<NUM>) or a ground voltage; and
a second switching unit (<NUM>) configured to switch a voltage output from the first switching unit (<NUM>) ON or OFF.