KR20180114803A - Liquid lens, camera module, and optical apparatus - Google Patents

Abstract

According to an embodiment of the present invention, a liquid lens capable of securing linearity without using a voltage driver with a higher resolution comprises: a cavity; a conductive liquid and a non-conductive liquid arranged in the cavity; and a common electrode and n number of individual electrodes, wherein n is an integer higher than or equal to two. An interface is formed between the conductive liquid and the non-conductive liquid. The amount of change of the average driving voltage in a first range of a first driving voltage code is higher than the amount of change of the average driving voltage in a second range of the first driving voltage code, wherein the average driving voltage is the average voltage of each driving voltage applied to the common electrode and the n number of individual electrodes, a lower limit of the second range is higher than an upper limit of the first range, and the first driving voltage code corresponds to the average driving voltage.

Description

[0001] LIQUID LENS, CAMERA MODULE, AND OPTICAL APPARATUS [0002]

The present invention relates to a liquid lens, a camera module and an optical device. More particularly, the present invention relates to a liquid lens, a camera module, and an optical device that can adjust a focal distance using electric energy.

Users of portable devices have high resolution and are small in size and have various shooting functions (zoom-in / zoom-out, auto-focusing, AF), image stabilization, OIS) function and the like). Such a photographing function can be realized by a method of directly moving the lens by combining a plurality of lenses, but when the number of lenses is increased, the size of the optical device can be increased.

The autofocus and camera shake correction functions are performed by moving a plurality of lens modules fixed to a lens holder and having optical axes aligned in a vertical direction of an optical axis or an optical axis or by tilting, Device is used. However, the power consumption of the lens driving device is high. In order to protect the lens driving device, it is necessary to add a cover glass separately from the camera module.

Therefore, research is being conducted on a liquid lens that performs autofocus and shake correction functions by electrically adjusting the curvature of the interface between two liquids.

The present invention is to provide a liquid lens, a camera module, and an optical apparatus that can ensure linearity without using a higher resolution voltage driver.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

A liquid lens according to an embodiment of the present invention includes a cavity, a conductive liquid and a non-conductive liquid disposed in the cavity, and n individual electrodes (n is an integer of 2 or more) and a common electrode, And an amount of change in the average drive voltage in the first range of the first drive voltage code is larger than a change amount in the average drive voltage in the second range of the first drive voltage code, Wherein the average driving voltage is an average voltage of each driving voltage applied between the common electrode and each of the n individual electrodes, the lower limit value of the second range is larger than the upper limit value of the first range, May be a value corresponding to the average driving voltage.

A camera module according to an embodiment of the present invention includes a cavity, a conductive liquid and a nonconductive liquid disposed in the cavity, and n individual electrodes (n is an integer of 2 or more) and a common electrode, A liquid lens in which an interface is formed between the nonconductive liquid and the nonconductive liquid; And a control circuit which generates a driving voltage to be applied between any one of the common electrode and the n individual electrodes of the liquid lens, The variation amount is larger than the variation amount of the average driving voltage in the second range of the first driving voltage code and the average driving voltage is an average voltage of each driving voltage applied between the common electrode and each of the n individual electrodes , The lower limit value of the second range may be larger than the upper limit value of the first range, and the first driving voltage code may be a value corresponding to the average driving voltage.

According to an embodiment, the control circuit may further include: a code conversion unit that receives the first driving voltage code and converts the first driving voltage code into a second driving voltage code having a higher resolution than the first driving voltage code; And a code conversion information providing unit having a conversion table or a conversion algorithm for converting the first drive voltage code into the second drive voltage code.

According to the embodiment, the control circuit may further include a voltage driver which generates the respective drive voltages based on the converted second drive voltage codes.

According to an embodiment, the conversion table is a table that matches the first driving voltage code and the second driving voltage code to each other to correct the first driving voltage code and the diopter of the interface to have a linear relationship .

According to an embodiment, the control circuit may further include a drive voltage code determination unit that determines drive voltage codes for the electrodes corresponding to the first to n-th drive electrodes in accordance with the second drive voltage code.

According to an embodiment, the conversion table may include a first drive voltage code and a drive signal for each electrode corresponding to each of the n individual electrodes, for correcting the first drive voltage code and the diopter of the interface to have a linear relationship, And the voltage code may be matched to each other.

According to an embodiment, the conversion algorithm may be a conversion function between the first driving voltage code and the second driving voltage code to correct the first driving voltage code and the diopter of the interface to have a linear relationship.

According to an embodiment, at least two driving voltage cords of the driving voltage cords corresponding to each of the n individual electrodes may be different from each other.

According to an embodiment, the conversion table or the conversion algorithm may be configured to calculate, from the relationship between the first driving voltage code and the diopter of the interface, the first driving voltage code and the second driving voltage code using at least one of normalization, The diopter of the interface can be determined to have a linear relationship.

A liquid lens according to another embodiment of the present invention includes a cavity, a conductive liquid and a nonconductive liquid disposed in the cavity, and n individual electrodes (n is an integer of 2 or more) and a common electrode, And the first driving voltage code for determining the average driving voltage and the diopter of the interface have a linear relationship and as the first driving voltage code is sequentially changed, The voltage is irregularly changed and the average driving voltage may be an average voltage of each driving voltage applied between the common electrode and each of the n individual electrodes.

An optical apparatus according to an embodiment of the present invention includes a camera module; A display unit for outputting an image; A battery for supplying power to the camera module; And a housing for mounting the camera module, the display unit, and the battery.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And can be understood and understood.

The effect of the device according to the present invention will be described as follows.

According to the liquid lens, the camera module and the optical apparatus according to the embodiment of the present invention, the linear relationship between the driving voltage code and the diopter at the interface of the liquid lens is secured by converting the driving voltage code using the driving voltage code having higher resolution .

The effects obtainable by the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

1 illustrates an example of a camera module according to an embodiment of the present invention.
2 illustrates an example of a lens assembly included in the camera module.
3 is a block diagram schematically showing the camera module shown in Fig.
Fig. 4 illustrates a liquid lens whose interface is adjusted corresponding to the driving voltage.
5 is a view for explaining an embodiment of a voltage supplied to both ends of a liquid lens.
6 is a view for explaining a voltage application method of a liquid lens according to an embodiment of the present invention.
FIG. 7 is a view for explaining a voltage application method of a liquid lens according to an embodiment of the present invention shown in FIG. 6 in terms of one driving electrode.
8 is a view for explaining an effect of a driving voltage applying method according to an embodiment of the present invention.
9 and 10 are views for explaining an embodiment of a method of applying a voltage to a liquid lens.
11 is a view for explaining another embodiment of the voltage applying method of the liquid lens.
12 is a block diagram showing the controller shown in FIG. 3 in more detail.
13 to 16 illustrate an embodiment in which, for a linearly increasing first drive voltage code, a second drive voltage code can be obtained to allow the diopter of the liquid interface to increase linearly .
17 is a diagram showing an embodiment of a conversion table according to an embodiment of the present invention.
18 is a view showing another embodiment of the conversion table according to another embodiment of the present invention.
19 is a view for explaining an application example of a driving voltage applying method according to an embodiment of the present invention.
FIGS. 20 and 21 are diagrams for explaining the effect of the driving voltage applying method according to the embodiment of the present invention.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. The embodiments are to be considered in all aspects as illustrative and not restrictive, and the invention is not limited thereto. It is to be understood, however, that the embodiments are not intended to be limited to the particular forms disclosed, but are to include all modifications, equivalents, and alternatives falling within the spirit and scope of the embodiments.

The terms "first "," second ", and the like can be used to describe various components, but the components should not be limited by the terms. The terms are used for the purpose of distinguishing one component from another. In addition, terms specifically defined in consideration of the constitution and operation of the embodiment are only intended to illustrate the embodiments and do not limit the scope of the embodiments.

In the description of the embodiments, when it is described as being formed on the "upper" or "on or under" of each element, the upper or lower (on or under Quot; includes both that the two elements are in direct contact with each other or that one or more other elements are indirectly formed between the two elements. Also, when expressed as "on" or "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

It is also to be understood that the terms "top / top / top" and "bottom / bottom / bottom", as used below, do not necessarily imply nor imply any physical or logical relationship or order between such entities or elements, And may be used to distinguish one entity or element from another entity or element.

1 illustrates an example of a camera module according to an embodiment of the present invention.

Referring to FIG. 1, the camera module 10 may include a lens assembly 22 including a liquid lens and a plurality of lenses, a control circuit 24, and an image sensor 26.

The liquid lens may include a conductive liquid and a non-conductive liquid, a first plate, and an electrode portion. The first plate may include a cavity for receiving a conductive liquid and a non-conductive liquid. The electrode unit may be electrically connected to an external power source to change the interface between the conductive liquid and the nonconductive liquid under a voltage. The liquid lens may further include an insulating layer disposed on the electrode portion to prevent contact between the electrode and the nonconductive liquid.

The camera module to which the liquid lens is applied may include a control unit for controlling the voltage applied to the electrode unit. The electrode unit may include a first electrode and a second electrode, and the first electrode and the second electrode may include at least one electrode sector. The first electrode and the second electrode can be electromagnetically interacted to change the interface between the conductive liquid and the nonconductive liquid.

The lens assembly 22 may include a plurality of lenses. The lens assembly 22 may be composed of a plurality of lenses including a liquid lens, and the focal length of the liquid lens may be adjusted corresponding to a driving voltage applied to the first electrode and the second electrode. The camera module 22 may further include a control circuit 24 for supplying a driving voltage to the liquid lens. The first electrode may be a separate electrode, and the second electrode may be a conductive metal plate and may be a common electrode.

The camera module 10 may include a plurality of circuits 24 and 26 disposed on a single printed circuit board (PCB) and a lens assembly 22 comprising a plurality of lenses, But does not limit the scope of the invention. The configuration of the control circuit 24 can be designed differently according to the specifications required for the optical device. In particular, in order to reduce the magnitude of the operating voltage applied to the lens assembly 22, the control circuit 24 may be implemented as a single chip. As a result, the size of the optical apparatus mounted on the portable apparatus can be further reduced.

Fig. 2 illustrates an example of the lens assembly 22 included in the camera module 10. Fig.

The camera module 10 may be included in an optical device. The optical apparatus may include a housing for mounting at least one of a camera module, a display unit, a communication module, a memory storage unit, and a battery.

Referring to FIG. 2, the lens assembly 22 may include a first lens unit 100, a second lens unit 200, a liquid lens 300, a holder 400, and a connection unit 500.

The connection portion 500 may be one or more than two. For example, in the case of having one connection portion, a part of the connection portion may be disposed on the upper or lower portion of the liquid lens 300 and may be connected to the liquid lens 300. In the case of having two connection portions, And a second connection part connected to the lower part of the liquid lens. One end of the connection portion may be electrically connected to the substrate on which the image sensor 26, which is disposed below the lens assembly 22 and on which the image sensor is mounted, is disposed. The structure of the illustrated lens assembly 22 is only one example, and the structure of the lens assembly 22 may be changed according to the specifications required for the optical apparatus. For example, in the illustrated example, the liquid lens 300 is positioned between the first lens unit 100 and the second lens unit 200, but in other examples, the first lens unit or the second lens unit may be omitted . Also, the liquid lens 300 may be located on the upper surface (front surface) of the first lens unit 100, or the liquid lens 300 may be positioned below the second lens unit. The liquid lens 300 includes a cavity defined by the opening area. In the another example, the liquid lens 300 may be disposed such that the inclination direction of the cavity 310 is opposite. 2, it may mean that the opening area of the cavity 310 in the incident direction is narrower than the opening area of the opposite direction. When the liquid lens 300 is disposed so that the inclined direction of the cavity 310 is opposite to the liquid lens 300, the arrangement of the liquid lens such as the electrode and the liquid may be changed in whole or in part along the oblique direction of the liquid lens, And the remaining batches may not be changed.

The first lens unit 100 is disposed in front of the lens assembly 22 and receives light from the outside of the lens assembly 22. The first lens unit 100 may be composed of at least one lens, or two or more lenses may be aligned with respect to the central axis PL to form an optical system.

The first lens unit 100 and the second lens unit 200 may be mounted on the holder 400. At this time, a through hole is formed in the holder 400, and the first lens unit 100 and the second lens unit 200 may be disposed in the through hole. In addition, the liquid lens 300 may be inserted into the space between the first lens unit 100 and the second lens unit 200 in the holder 400.

Meanwhile, the first lens unit 100 may include an exposure lens 110. The exposure lens 110 refers to a lens that protrudes outside the holder 400 and can be exposed to the outside. In the case of the exposure lens 110, the lens surface may be damaged due to exposure to the outside. If the lens surface is damaged, the image quality of the image taken by the camera module may be deteriorated. A method of disposing a cover glass, forming a coating layer, or constructing the exposure lens 100 with a wear resistant material for preventing surface damage may be applied in order to prevent or suppress the surface damage of the exposure lens 110.

The second lens unit 200 is disposed behind the first lens unit 100 and the liquid lens 300 and the light incident from the outside to the first lens unit 100 passes through the liquid lens unit 300 Can be incident on the second lens unit (200). The second lens unit 200 may be disposed in the through hole formed in the holder 400, spaced apart from the first lens unit 100.

Meanwhile, the second lens unit 200 may include at least one lens, and when two or more lenses are included, the optical system may be formed by aligning with respect to the center axis PL.

The liquid lens 300 is disposed between the first lens unit 100 and the second lens unit 200 and can be inserted into the insertion port 410 of the holder 400. [ The liquid lens 300 may also be aligned with respect to the center axis PL in the same manner as the first lens unit 100 and the second lens unit 200. One or at least two insertion ports 410 of the holder 400 may be formed on the side of the holder 400. The liquid lens may be disposed in the insertion port 410. The liquid lens may protrude outwardly from the insertion port 410.

The liquid lens 300 may include a cavity 310. The cavity 310 is a portion through which the light passing through the first lens unit 100 is transmitted, and may include at least a part of the liquid. For example, the cavity 310 may include two types, that is, a conductive liquid and a nonconductive liquid (or an insulating liquid) together, and the conductive liquid and the nonconductive liquid are not mixed with each other, Can be formed. The interface between the conductive liquid and the nonconductive liquid may be deformed by the driving voltage applied through the connection part 500 so that the curvature and / or the focal length of the liquid lens 300 may be changed. The liquid lens 300 and the lens assembly 22 and the optical device including the liquid lens 300 may have functions such as an auto-focusing (AF) function, an optical image stabilizer , OIS) function, and the like.

3 is a block diagram schematically showing the camera module shown in Fig.

3, a control circuit 210 and a lens assembly 250 included in the camera module 200 are shown and each of the control circuit 210 and the lens assembly 250 is connected to the control circuit 24 And the lens assembly 22, respectively.

The control circuit 210 may include a controller 220.

The control unit 220 is a unit for performing the AF function and the OIS function and controls the operation of the liquid lens (not shown) included in the lens assembly 250 by using a user's request or a detection result (for example, a motion signal of the gyro sensor 225) 260 can be controlled.

The controller 220 may include a controller 230 and a voltage driver 235. The gyro sensor 225 may be an independent configuration not included in the control unit 220 and the control unit 220 may further include the gyro sensor 225. [

The gyro sensor 225 can sense angular velocities of movement in two directions, a yaw axis and a pitch axis, to compensate for camera shake in up, down, left, and right directions of the optical device 200. The gyro sensor 225 may generate a motion signal corresponding to the detected angular velocity and provide the motion signal to the controller 230.

The controller 230 extracts only a desired band by removing a noise component of a high frequency from a motion signal using a low pass filter (LPF) to implement the OIS function, And calculate a driving voltage corresponding to a shape of the liquid lens 280 of the liquid lens 260 to compensate for the calculated shaking motion.

The controller 230 receives information for the AF function (i.e., distance information with respect to the object) from the inside of the optical device or the camera module 200 (e.g., an image sensor) or from an external And calculate the driving voltage corresponding to the shape of the liquid lens 280 according to the focal distance for focusing on the object through the distance information.

The controller 230 may store a driving voltage table in which a driving voltage and a driving voltage code for causing the voltage driver 235 to generate the driving voltage are mapped to a driving voltage code corresponding to the calculated driving voltage, Can be obtained by referring to the table.

The voltage driver 235 may generate an analog driving voltage corresponding to the driving voltage code on the basis of the driving voltage code of the digital form provided from the controller 230 and provide it to the lens assembly 250.

The voltage driver 235 includes a voltage booster for receiving a supply voltage (e.g., a voltage supplied from a separate power supply circuit) to increase the voltage level, a voltage stabilizer for stabilizing the output of the voltage booster, And a switching unit for selectively supplying the output of the voltage booster to the terminal.

Here, the switching unit may include a circuit configuration called an H bridge. And the high voltage output from the voltage booster is applied to the power supply voltage of the switching unit. The switching unit may selectively supply a power supply voltage and a ground voltage to both ends of the liquid lens 280. Here, the liquid lens 280 may include a first electrode including four electrode sectors and a second electrode including one electrode sector for driving, both ends of the liquid lens 280 may include a first electrode, May refer to a second electrode. Both ends of the liquid lens 280 may refer to any one of the four electrode sectors of the first electrode and one electrode sector of the second electrode.

A pulse voltage having a predetermined width may be applied to each electrode sector of the liquid lens 280. The driving voltage applied to the liquid lens 280 may be a voltage difference between the first electrode and the second electrode to be. Here, the voltage applied to the first electrode may be defined as an individual voltage, and the voltage applied to each of the electrode sectors of the second electrode may be defined as an individual voltage.

That is, in order for the voltage driver 235 to control the driving voltage applied to the liquid lens 280 in accordance with the digital driving voltage code provided from the controller 230, the voltage booster controls the increased voltage level, The switching unit controls the phase of the pulse voltage applied to the common electrode and the individual electrode so that an analog driving voltage corresponding to the driving voltage code is generated.

That is, the controller 220 can control the voltages applied to the first electrode and the second electrode.

The control circuit 210 may further include a connector (not shown) that performs communication or interface functions of the control circuit 210. For example, for communication between a control circuit 210 using an I²C (Inter-Integrated Circuit) communication scheme and a lens assembly 250 using a Mobile Industry Processor Interface (MIPI) communication scheme, Can be performed.

In addition, the connector may receive power from an external device (e.g., a battery) to supply power required for the operation of the controller 220 and the lens assembly 250.

The lens assembly 250 may include a liquid lens module 260 and the liquid lens module 260 may include a driving voltage supply unit 270 and a liquid lens 280.

The driving voltage supply unit 270 receives a driving voltage (that is, an analog voltage applied between any one of the four individual electrodes and one common electrode) from the voltage driver 235, The driving voltage can be supplied to the driving circuit. The driving voltage providing unit 270 may include a voltage adjusting circuit or a noise removing circuit for compensating for a loss due to terminal connection between the control circuit 210 and the lens assembly 250, bypass.

The driving voltage supply unit 260 may be disposed on an FPCB (Flexible Printed Circuit Board) constituting at least a part of the connection unit 500 of FIG. 2, but the scope of the present invention is not limited thereto. The connection unit 500 may include a driving voltage supply unit 260.

The interface between the conductive liquid and the nonconductive liquid is deformed according to the driving voltage to perform the AF function or the OIS function.

Fig. 4 illustrates a liquid lens whose interface is adjusted corresponding to the driving voltage. Specifically, (a) illustrates the liquid lens 28 included in the lens assembly 250 (see FIG. 3), and (b) illustrates an equivalent circuit of the liquid lens 28. FIG. Here, the liquid lens 28 means the liquid lens 280 in Fig.

First, referring to (a), a liquid lens 28 whose interface is adjusted in response to a driving voltage is divided into a plurality of electrode sectors L 1 and L 2 , L3 and L4 and the electrode sector C0 of the second electrode. When a drive voltage is applied through a plurality of electrode sectors L1, L2, L3 and L4 constituting the first electrode and an electrode sector C0 constituting the second electrode, the conductive liquid and the non- The interface of the liquid can be deformed. The degree and shape of the interface deformation of the conductive liquid and the nonconductive liquid may be controlled by the controller 230 to implement the AF function or the OIS function.

One side of the lens 28 receives a voltage from the different electrode sectors L1, L2, L3 and L4 of the first electrode and the other electrode of the second electrode C0 And a plurality of capacitors 30 connected to the plurality of capacitors 30 to receive a voltage.

In the present specification, four different electrode sectors are described as examples, but the scope of the present invention is not limited thereto.

5 is a view for explaining an embodiment of a voltage supplied to both ends of a liquid lens.

5, a voltage of a pulse shape having a predetermined width may be applied to each of the electrode sectors C0 and L1 to L4 of the liquid lens 280. The electrode sectors L1 to L4 of the first electrode, And the electrode sector C0 of the second electrode becomes the driving voltage.

The voltage driver 235 can control the driving voltage corresponding to each individual electrode by controlling the phase of the pulse voltage applied to the common electrode sector and the individual electrode sector.

5, the voltage driver 235 can shift the phase of the pulse voltage according to an operation clock supplied from the outside. The first pulse voltage A applied to the individual electrode sector L1 The second pulse voltage B is shown. The second pulse voltage B is a voltage obtained by delaying the first pulse voltage A by a minimum phase.

The driving voltage 2 of the driving voltage 2 when the second pulse voltage B is applied to the individual electrode sector L1 is smaller than the driving voltage 1 when the first pulse voltage A is applied to the individual electrode sector L1 Is higher. Here, the RMS (Root Mean Square) value of the driving voltage directly contributes to the control of the interface of the liquid lens 280.

The minimum phase is determined by the frequency of the operating clock to which the voltage driver 235 is provided. The minimum phase may determine the resolution of the output voltage of the voltage driver 235, and the smaller the minimum phase, the higher the resolution of the output voltage of the voltage driver 235 may be.

However, if the resolution of the output voltage of the voltage driver 235 is to be doubled, the voltage driver 235 must be provided with an operation clock having a frequency two times higher than that of the voltage driver 235, which requires a high-performance clock generator. This leads to a considerable loss in terms of cost, power consumption and the like from the viewpoint of the entire system, and therefore, a method of increasing the resolution of the output voltage of the voltage driver 235 without a high-performance clock generator is required.

6 is a view for explaining a voltage application method of a liquid lens according to an embodiment of the present invention.

Referring to FIG. 6, the driving voltage application method of FIG. 6 and the following description will be focused on providing an auto focusing function. However, the scope of the present invention is not limited thereto. . Further, the voltage level and the timing of the voltage applied to the liquid lens described in Fig. 6 and below can be controlled by the driving voltage code generated by the controller 230. [

Four liquid lenses are shown for each cycle (CYCLE1 to CYCLE1-4). An electrode sector located on the upper left side of the first electrode of one liquid lens is defined as a first electrode sector, and the center And the electrode sectors sequentially disposed in the clockwise direction from the first electrode sector are defined as a second electrode sector, a third electrode sector, and a fourth electrode sector, respectively.

Each of the first to fourth driving electrodes means a pair of the common electrode sector of the corresponding one of the first to fourth electrode sectors and the corresponding one of the first to fourth driving electrodes, Are defined as first to fourth drive voltages, respectively.

The first to fourth driving voltages correspond to the voltage difference between the first to fourth voltages applied to the first to fourth electrode sectors and the voltage applied to the second electrode, respectively. The first to fourth drive voltages may mean an average value or an RMS value of the voltage difference within one cycle.

A unit cycle for deforming the interface of the liquid lens can be defined, and corresponds to the first to fourth cycles (CYCLE1 to CYCLE4) shown in Fig.

The time corresponding to the unit cycle may be determined in consideration of an auto focusing response time, i.e., a time required for the liquid lens to be deformed to a desired interface after application of the driving voltage. The autofocusing reaction time may vary depending on the specifications of the liquid lens, but the autofocusing reaction time may have a reaction time of about 50 ms, so that the unit cycle can be determined in consideration of the autofocusing reaction time and the number of subcycles .

The controller 230 of FIG. 3 calculates the driving voltage and transmits the driving voltage code to the voltage driver 235 through the bidirectional serial data port (SDA) and the clock port (SCL) 1Mhz can be supported.

The voltage driver 235 generates a drive voltage corresponding to the drive voltage code, based on the drive voltage code received from the controller 230, which is applied to each capacitor 30 shown in FIG. 4 The first to fourth drive voltages for the first electrode, the second electrode, the fourth electrode, and the second electrode for applying the drive voltage.

The first to fourth driving voltages have a maximum output voltage, a minimum output voltage, and a constant unit voltage according to the structure of the voltage driver 235, and the maximum output voltage and the minimum output voltage are set so that the voltage driver 235 outputs And the unit voltage means a voltage capable of increasing or decreasing each of the first to fourth driving voltages to a minimum. The unit voltage may be determined by a minimum phase determined according to the frequency of the operation clock when the voltage driver 235 adjusts the output voltage in such a manner that the phase of the pulse voltage is shifted according to the operation clock.

However, it is needless to say that each of the first to fourth drive voltages need not be increased or decreased by 1V, and may be increased or decreased by, for example, 10V.

For example, when the maximum output voltage is 70V and the minimum output voltage is 41V and the unit voltage is 1V, the first to fourth separate voltages may have 30 voltages within a range of 41V to 70V, respectively.

That is, assuming that the same driving voltage is applied to the first to fourth driving electrodes for the auto focusing function, the auto focusing resolution of 30 steps can be realized.

In this case, k (k is an integer equal to or greater than 1 and equal to or less than N; N is an integer equal to or greater than 2) th driving voltage Vk is expressed by Equation 1 below. Here, the kth driving voltage means a minimum driving voltage when the minimum output voltage is the first driving voltage and the maximum output voltage is the Nth driving voltage.

[Equation 1]

Vk = Vi + dv * k

Here, Vi denotes the minimum output voltage and dv denotes the unit voltage.

Therefore, if the same drive voltage is applied to the first to fourth drive electrodes within a constant output voltage range (range between the maximum output voltage and the minimum output voltage), the unit voltage for the drive voltage is the unit voltage of the voltage driver 235 And the autofocusing resolution depends on the unit voltage of the voltage driver 235. The autofocusing resolution is the most important factor affecting the performance of the autofocusing function because it determines the degree of fine adjustment of the autofocusing function.

Hereinafter, a driving voltage applying method capable of increasing autofocusing resolution within a constant output voltage range will be described.

Although not shown in FIG. 6, in the initial cycle before the first cycle (CYCLE1), the individual voltages applied to the first to fourth electrode sectors are V (V is an arbitrary voltage within an output voltage range, Quot;).

As shown in FIG. 6, each cycle (CYCLE1 to CYCLE4) can be divided into four subcycles in total. The times of each sub-cycle may be the same or different. In one embodiment in which the time of each sub-cycle is the same, if each cycle (CYCLE1-4) has a time of 50 ms, the time of each sub-cycle may be 12.5 ms. The voltage applied to each driving electrode in one sub-cycle can be maintained. According to another embodiment, the voltage applied to each driving electrode in one sub-cycle can be varied. For example, the first and second cycles in the second cycle (CYCLE2), and the third and fourth cycles, respectively, can be defined as constituting one sub-cycle. In this case, the time of each sub-cycle may be 25 ms.

(V + dv, V, V, V) in the first sub-cycle of the first cycle (CYCLE1) V, V, V + dv, V) may be applied in the fourth sub-cycle. Here, a, b, c, and d in (a, b, c, d) denote first to fourth driving voltages, respectively.

That is, a voltage (V + dv, hereinafter referred to as a 'second voltage') in which any one of the first to fourth driving voltages in the first sub-cycle of the first cycle (CYCLE1) is increased from the initial voltage by a unit voltage ), And apply the remaining driving voltage to the initial voltage (V, hereinafter referred to as 'first voltage'). In the subsequent sub-cycle, the position at which the second voltage is sequentially applied in the clockwise direction can be changed. Here, the driving electrode to which the second voltage is applied is shaded, and the clockwise direction is only one embodiment, and it can be set in a counterclockwise direction, a zigzag direction, and the like.

However, the position where the second voltage is applied in each sub-cycle must be set differently, because the interface of the liquid lens may be unstable when the second voltage is continuously applied to any one position.

The driving voltage applied to one of the driving electrodes in one cycle corresponds to the average of the driving voltages applied in four sub-cycles.

Therefore, the first to fourth driving voltages applied in the first cycle (CYCLE1) correspond to (4V + dv) / 4 = V + dv / 4.

(V + dv, V, V + dv, V) in the first sub-cycle of the second cycle (CYCLE2) (V + dv, V, V + dv, V) can be applied in the cycle and (V, V + dv, V, V + dv) in the fourth subcycle.

That is, in the first sub cycle of the second cycle (CYCLE2), either one of the first to fourth driving voltages may be applied as the second voltage and the remaining driving voltage may be applied as the first voltage. The driving voltage at the position where the first voltage is applied may be applied as the second voltage and the driving voltage at the position where the second voltage is applied may be applied as the first voltage in the second sub cycle. In the subsequent sub-cycles, the driving voltage application method of the first sub-cycle and the second sub-cycle may be repeated. The second cycle (CYCLE2) can also change the voltage application position in the clockwise or counterclockwise direction as in the subcycle of the first cycle (CYCLE1).

As shown in FIG. 6, the driving voltages corresponding to the opposite positions are set to be the same, and the positions where the second voltage is applied in the adjacent sub-cycles must be set to be different from each other in order to prevent the liquid lens interface from being distorted. Although not shown in the drawing, the first voltage may be applied to two adjacent electrode sectors of the four electrode sectors, and the second voltage may be applied to the remaining electrode sectors to control the voltage application in the clockwise or counterclockwise direction.

The first to fourth drive voltages applied in the second cycle CYCLE2 correspond to (4V + 2dv) / 4 = V + dv / 2.

(V, V + dv, V + dv, V + dv) in the first sub-cycle of the third cycle (CYCLE3) (V + dv, V, V + dv, V + dv) may be applied in the third sub-cycle and (V + dv, V + dv, V, V + dv) may be applied in the fourth sub-cycle.

In other words, three of the first to fourth driving voltages may be applied as the second voltage and the remaining driving voltage may be applied as the first voltage in the first sub-cycle of the third cycle (CYCLE3). In the subsequent sub-cycle, the position where the first voltage is sequentially applied in the clockwise direction can be changed. Here, the clockwise direction is only one embodiment, and it is of course possible to set the counterclockwise direction, the zigzag direction, and the like.

However, the position where the first voltage is applied in each sub-cycle must be set differently, because the interface of the liquid lens may be unstable when the first voltage is continuously applied to any one position.

Therefore, the first to fourth drive voltages applied in the third cycle (CYCLE3) correspond to (4V + 3dv) / 4 = V + 3dv / 4.

(V + dv, V + dv, V + dv, V + dv) in the first sub-cycle of the fourth cycle (CYCLE4) (V + dv, V + dv, V + dv, V + dv) in the third sub-cycle, (V + dv, V + dv, V + dv) may be applied.

That is, all the first to fourth driving voltages may be applied to the first to fourth sub-cycles of the fourth cycle CYCLE3 as the second voltage.

Therefore, the first to fourth drive voltages applied in the fourth cycle (CYCLE4) correspond to (4V + 4dv) / 4 = V + dv.

At this time, the sum of the first to fourth driving voltages applied in the sub-cycle included in the same cycle can be kept constant, which means that the total sum of the first to fourth driving voltages in one cycle must be kept constant, Because the distance can be maintained in that cycle.

According to the driving voltage applying method according to an embodiment of the present invention, the k-th separate voltage V'k is given by the following equation (2).

&Quot; (2) "

V'k = Vi + dv / 4 * k

Here, Vi denotes the minimum output voltage and dv denotes the unit voltage.

Therefore, after the first to fourth drive voltages are not applied with the same drive voltage within a constant output voltage range, and after all of the first to fourth drive voltages are set to the first voltage, Only one of the first to fourth driving voltages is set to the second voltage and the driving voltage set to the second voltage is set to the second voltage, And a cycle for rotating the driving voltage set to the second voltage are further inserted so that the unit voltage for determining the auto focusing resolution becomes dv / 4 . ≪ / RTI >

In other words, the fact that the unit voltage is reduced to 1/4 means that the auto focusing resolution is increased four times, and the performance of the auto focusing function can be improved remarkably.

For example, since the maximum output voltage is 70V, the minimum output voltage is 41V, and the unit voltage is 0.25V, the first to fourth drive voltages can have 120 voltages within a range of 41V to 70V, respectively .

According to another embodiment, it is also possible to use only a part of the cycles shown in FIG. 5. For example, when only the voltage applying method according to the second cycle (CYCLE2) of the first to third cycles (CYCLE1 to CYCLE2) The resolution of the autofocusing function can be doubled.

FIG. 7 is a view for explaining a voltage application method of a liquid lens according to an embodiment of the present invention shown in FIG. 6 in terms of one driving electrode.

Referring to FIG. 7, driving voltages applied to the driving electrodes corresponding to the first electrode sector L1 in each cycle (CYCLE0 to CYCLE4) are shown.

The driving voltage indicated by white means a period in which the first voltage V is applied and the driving voltage indicated in gray shades is the voltage applied to the first electrode sector L1 shifted by a minimum phase, (V + dv) whose unit voltage is higher than the first voltage (V + dv) is applied.

Each cycle (CYCLE0 to CYCLE4) can be divided into four sub-cycles (SUB1 to SUB4).

In the initial cycle CYCLE0, the first voltage V may be applied to the first driving electrode in all the sub-cycles SUB1 through SUB4. Therefore, the first driving voltage applied to the first driving electrode in the initial cycle (CYCLE0) corresponds to V.

In the first cycle (CYCLE1), the second voltage (V + vd) is applied to one of the sub-cycles (SUB1) of all the sub-cycles (SUB1 to SUB4) A first voltage V may be applied. Accordingly, the first driving voltage applied to the first driving electrode in the first cycle (CYCLE1) corresponds to V + dv / 4.

In the second cycle CYCLE2, the second voltage V + vd is applied to the first driving electrode in two sub-cycles SUB1 and SUB2 among the sub-cycles SUB1 to SUB4 and the remaining sub-cycles SUB3 and SUB3 The first voltage V may be applied. Therefore, the first driving voltage applied to the first driving electrode in the second cycle CYCLE1 corresponds to V + dv / 2.

In the third cycle (CYCLE3), the second voltage (V + vd) is applied to the first driving electrode in three sub-cycles (SUB1 to SUB3) of all the sub-cycles (SUB1 to SUB4) A first voltage V may be applied. Accordingly, the first driving voltage applied to the first driving electrode in the third cycle (CYCLE3) corresponds to V + 3dv / 4.

In the fourth cycle (CYCLE4), the second voltage (V + dv) may be applied to the first driving electrode in all of the sub-cycles (SUB1 to SUB4). Accordingly, the first driving voltage applied to the first driving electrode in the fourth cycle CYCLE4 corresponds to V + dv.

Here, the number of sub-cycles to which the first voltage and the second voltage are applied to one driving electrode in the cycles (CYCLE1 to CYCLE3) in which different driving voltages are applied to the respective driving electrodes must be the same in all the driving electrodes. However, whether or not the first voltage and the second voltage are applied in which of the plurality of sub-cycles for one drive electrode can be determined by various methods.

For example, as illustrated in the description of FIG. 6, the position of the driving electrode to which the first voltage or the second voltage is applied in the adjacent sub-cycle may move clockwise, counterclockwise, or zigzag.

The position of the sub-cycle to which the second voltage is applied to the first driving electrode is somewhat different from that of FIG. 6, however, this is for convenience of description and does not depart from the scope of the technical idea of the present invention.

8 is a view for explaining an effect of a driving voltage applying method according to an embodiment of the present invention.

Referring to FIG. 8, the average voltage applied to the electrode sector in each cycle (CYCLE0-4) illustrated in FIGS. 6 and 7 is shown.

The average voltage applied to the first to fourth driving electrodes in the initial cycle CYCLE0 is V, the average voltage applied to the first to fourth driving electrodes in the first cycle CYCLE1 is V + dv / 4, The average voltage applied to the first to fourth driving electrodes in the second cycle (CYCLE2) is V + dv / 2, and the average voltage applied to the first to fourth driving electrodes in the third cycle (CYCLE3) 4, and the average voltage applied to the first to fourth driving electrodes in the fourth cycle (CYCLE4) is V + dv.

That is, when the driving voltage is sequentially increased for each cycle, the unit voltage may be increased by dv / 4, which corresponds to a value reduced by 1/4 from the unit voltage dv of the voltage driver 235.

That is, when the same driving voltage is applied to the first to fourth driving electrodes, the unit voltage with respect to the driving voltage for determining the auto focusing resolution becomes equal to the unit voltage of the voltage driver 235, When the driving voltage is sequentially increased in the first cycle (CYCLE1) from the initial cycle (CYCLE0) to which the driving voltage of the first sub-cycle (CYCLE0) is applied, the driving voltage of V + dv must be applied immediately. have.

6 and 7, the unit voltage with respect to the driving voltage for determining the auto focusing resolution is 1/4 of the unit voltage of the voltage driver 235, and in FIG. 8 It is possible to apply the driving voltage of V + dv / 4 immediately in order to sequentially increase the driving voltage in the first cycle (CYCLE1) from the initial cycle (CYCLE0) to apply the driving voltage of V, it is possible to have four steps for applying the driving voltage of dv. That is, the method according to an embodiment of the present invention may have a fourfold autofocus resolution.

Although the liquid lens has four individual electrodes in this specification, the scope of the present invention is not limited to this, and the present invention can be applied to a case having eight, sixteen, etc. individual electrodes.

For example, when the liquid lens has eight individual electrodes, one cycle can be divided into eight sub-cycles, and the driving voltage is applied in such a manner that the number of the individual electrodes for applying the second voltage is sequentially increased . At this time, the unit voltage for the driving voltage may be 1/8 of the unit voltage of the voltage driver 235, which may increase the autofocusing resolution by a factor of eight.

In general, if the first to p-th driving voltages corresponding to the first to p-th (p is an integer of 2 or more) driving electrodes are applied to the first voltage or the second voltage, P-1 cycles of applying a driving voltage of q (q is an integer equal to or greater than 1 and equal to or less than p-1) driving voltages to the second voltage among the first through p-th driving voltages may be added to increase the auto focusing resolution.

Also, in a cycle in which q driving voltages among the first through p-th driving voltages are applied as a second voltage, one of the driving electrodes may be applied with a second voltage in q sub-cycles.

As described above, according to the driving voltage applying method of the present invention, it is possible to increase the auto focusing resolution by reducing the unit voltage for the driving voltage in a constant output voltage range of the voltage driver.

In addition, it is possible to reduce the power consumption of the optical device by increasing the autofocusing resolution while not requiring an increase in the output voltage range of the voltage driver.

9 and 10 are views for explaining an embodiment of a method of applying a voltage to a liquid lens.

Referring to FIG. 9, it is assumed that the driving voltage code obtained by the controller 230 has a resolution of 10 bits. Accordingly, the driving voltage code has a range from 0 to 1023, and the driving voltage code selected from 0 to 1023 is transmitted to the voltage driver 235. The voltage driver 235 may generate the driving voltages of the first to fourth driving electrodes corresponding to the selected one of the driving voltage codes, and the driving voltage may be a voltage corresponding to each of the driving voltage codes of 0 to 1023 Lt; RTI ID = 0.0 > A0 < / RTI >

Here, the amount of change (V1 = A1-A0) of the drive voltage when the drive voltage code rises from 0 to 1 can be constant in the range of all the drive voltage codes. Therefore, the change amount of the drive voltage (V1023 = A1023-A1022) when the drive voltage code rises from 1022 to 1023 can be equal to V1. For example, the amount of change in the driving voltage when the driving voltage code is increased by one may be constant at 0.045V.

On the other hand, the driving voltage is applied to the first to fourth driving electrodes of the liquid lens 280 according to the driving voltage outputted by the voltage driver 235, and the interface (i.e., the liquid interface) between the conductive liquid and the non- It can be deformed. At this time, assuming that the same driving voltage is applied to the first to fourth driving electrodes of the liquid lens 280, the average (i.e., average driving voltage) of the driving voltages of the first to fourth driving electrodes and the average And the diopter of the deformed interface has the relationship of the following equation (3) with the average driving voltage. If the average driving voltage is expressed in general terms, the average driving voltage may be an average voltage of each driving voltage applied between the common electrode and each of n (n is an integer of 2 or more) individual electrodes. The first drive voltage code and the second drive voltage code may each be a value corresponding to a specific average drive voltage. The diopter is a reciprocal of the focal length of the interface and is a direct factor of focal distance.

&Quot; (3) "

The diopter alpha of the interface. The mean square of the drive voltage

For example, the diopter of the liquid interface deformed corresponding to the driving voltage code 0 is not proportional to the driving voltage A0, but is proportional to the square of A0.

That is, the driving voltage may also be raised (for example, 0.045 V) as the driving voltage code is raised (for example, by 1) constantly, but the diopter of the liquid interface is constantly proportional to the square of the driving voltage It does not rise. For example, the first diopter change amount D1 is completely different from the last diopter change amount D1023.

In other words, when the driving voltage code linearly increases, the driving voltage also increases linearly, but the diopter of the liquid interface increases in a form corresponding to the exponential function due to the relationship between the driving voltage and the liquid interface.

Referring to FIG. 10, there is shown a graph of the diopter of the liquid interface changing corresponding to 10-bit drive voltage code 1 to 1023. As shown in FIG. 10, the diopter is increased from about -40 diopters to about 80 diopters corresponding to the 10-bit driving voltage code 1 to 1023, but the driving voltage code is linearly increased, .

Therefore, in the case of an external controller (for example, an application processor) that transmits a driving voltage code to the controller 230 or the controller 230, it is difficult to control the diopter of the liquid interface linearly through the driving voltage code do.

11 is a view for explaining another embodiment of the voltage applying method of the liquid lens.

Referring to FIG. 11, the first driving voltage code has a 10-bit resolution similar to the driving voltage code shown in FIG. 9, and has a range of 0 to 1023. The second driving voltage code is a driving voltage applying method described in Figs. 6 to 8 (i.e., a method of applying driving voltage codes of at least two electrodes among the driving voltage cords corresponding to n individual electrodes to each other differently) A driving voltage code having a 12-bit resolution corresponding to a fourfold autofocusing resolution by reducing a unit voltage for a voltage driver having a constant output voltage range.

That is, by adopting a method (individual electrode drive) of applying a drive voltage different from that of the remaining electrodes to at least one drive electrode instead of a method of applying the same drive voltage to all of the four drive electrodes The average driving voltage outputted from the second driving voltage generator 235 may have a resolution of four times, and the second driving voltage code corresponding to this average driving voltage may have a resolution of 12 bits (0 to 4092).

11, when the average drive voltages corresponding to the first drive voltage codes 0, 1, and 2 are A0, A1, and A2, the second drive voltage codes correspond to 0, 4, and 8, The second drive voltage codes 1 to 3 and 5 to 7 may correspond to the average drive voltages of A0-1 to A0-3 and A1-1 to A1-3.

Therefore, the average driving voltage is increased by D1 (for example, 0.045V) in one code increase of the first driving voltage code, and D1 '( For example, 0.01125 V).

That is, the voltage driver 235 can be finely controlled according to the second driving voltage code using the driving voltage application method of FIGS. 6 to 8, and hereinafter, the first driving voltage code, the second driving voltage code, A method of controlling the diopter of the liquid interface linearly using the relationship between the driving voltages will be described.

12 is a block diagram showing the controller shown in FIG. 3 in more detail.

Referring to FIG. 12, the controller 1210 and the voltage driver 1250 may correspond to the controller 230 and the voltage driver 235 of FIG. 3, respectively.

The controller 1210 may calculate the driving voltage corresponding to the shape that the liquid lens should have according to the request of the gyro sensor or the image sensor as described in Fig. 3, acquire the first driving voltage code for the same using the table In the following description, the controller 1210 receives a first driving voltage code from an external configuration (for example, an application processor). It goes without saying that the method described below can also be applied when the controller 1210 directly generates the first driving voltage code.

The controller 1210 receives the first driving voltage code from the outside through an I 2 C (Inter Integrated Circuit) communication method, and generates a driving voltage code for each electrode (a driving voltage code for determining a driving voltage to be applied to each of the first to fourth driving electrodes And transmit it to the voltage driver 1250 in an I < 2 > C manner.

The controller 1210 may include a code converter 1220, a code conversion information providing unit 1230, and a driving voltage code determining unit 1240.

The code conversion unit 1220 can convert the first driving voltage code of 10 bits into the second driving voltage code of 12 bits, and at this time, by using the conversion table or the conversion algorithm provided from the code conversion information providing unit 1230 A conversion operation can be performed.

The code conversion information providing unit 1230 may have the conversion table or the conversion algorithm, and may provide the code conversion information to the code conversion unit 1220. The conversion table or the conversion algorithm corresponds to information capable of obtaining a second driving voltage code for allowing the diopter of the liquid interface to increase linearly with respect to the linearly increasing first driving voltage code. Details of the conversion table or the conversion algorithm will be described later with reference to FIGS. 13 to 18. FIG.

The drive voltage code determination unit 1240 may determine a drive voltage code corresponding to the drive voltage to be applied to each of the first to fourth drive electrodes using the second drive voltage code. The driving voltage code determination unit 1240 may sequentially transmit driving voltage codes for the electrodes corresponding to the first to fourth driving electrodes to the voltage driver 1250 in a predetermined order.

According to another embodiment, the driving voltage code determination unit 1240 may be omitted depending on the conversion table (the conversion table in FIG. 18) or the conversion algorithm provided by the code conversion information providing unit 1230.

The voltage driver 1250 can generate the respective driving voltages corresponding to the respective driving electrodes in accordance with the driving voltage code for each electrode corresponding to the first to fourth driving electrodes generated based on the converted second driving voltage code .

13 to 16 show an embodiment in which, for a linearly increasing first driving voltage code, a second driving voltage code for obtaining a linearly increasing diopter of the liquid interface can be obtained .

Referring to FIGS. 13 to 16, the left graph is a graph of the relationship between the first driving voltage code of 10 bits and the diopter of the liquid interface as shown in FIG. 10, and according to the relationship of Equation (3) Represents a form close to a function.

These graphs can be obtained by sequentially applying a driving voltage according to a first driving voltage code of 0 to 1023 after a specific liquid lens is manufactured, and actually measuring the focal length or the diopter. That is, it is a matter of course that the graph of the first driving voltage code and the diopter shown in Fig. 13 corresponds to a specific liquid lens, and another graph can be obtained for the liquid lens. In this case, however, the graph of the first driving voltage code and the diopter will have a shape close to the exponential function.

The graph on the right side of FIG. 13 is a graph obtained by normalizing the graph between the first driving voltage code of 10 bits and the diopter of the liquid interface so that the diopter has a value in the range of 0 to 1. That is, the diopter corresponding to the 10-bit first driving voltage code can be normalized so as to have the same tendency as the left graph within the range of 0 to 1.

14 is a graph between a first driving voltage code of 10 bits and a normalized diopter, which is a graph on the right side of FIG. 13. The graph of the graph between the first driving voltage code of 10 bits and the normalized diopter scale conversion can be performed by multiplying the y-axis coordinate by 1023. Here, the 10-bit diopter having the same upper and lower limit values as the first driving voltage code while maintaining the tendency between the first driving voltage code and the actual diopter by multiplying the normalized diopter by 1023, You can get a graph between the codes.

Diopters measured in the range of about -40 to 80 through normalization and scale conversion in FIGS. 13 and 14 can be represented by 10-bit diopters, which is a diopter having 10-bit resolution.

15 is a graph between a first driving voltage code and a 10-bit diopter. In the right graph, a graph having an inverse function relationship is obtained by changing the x-axis and the y-axis of the graph between the first driving voltage code and the 10-bit diopter, When the x-axis is represented by the first driving voltage code, a 10-bit resolution capable of compensating for the relationship between the first driving voltage code and the diopter, which has a relationship close to the exponential function, A 10-bit linear code can be obtained. Here, the linear relationship means that the diopter also linearly increases when the first driving voltage code linearly increases.

16 is a graph between the first driving voltage code and the 10-bit linear code. In the right graph of FIG. 16, the y-axis coordinate of the graph between the first driving voltage code and the 10-bit linear code is multiplied by 4, can do. Here, a 12-bit linear code having the same upper and lower limit values as the second driving voltage code while maintaining the tendency between the first driving voltage code and the 10-bit linear code by multiplying the 10-bit linear code by 4, A graph of the first driving voltage code can be obtained.

16, a second driving voltage code (0 to 4092) for making the first driving voltage code and the diopter have a linear relationship with respect to each of the first driving voltage codes (0 to 1023) can be obtained .

In this case, the code conversion information providing unit 1230 may store a conversion table in which the first driving voltage code, the first driving voltage code, and the second driving voltage code matching the diopter are mutually matched.

According to another embodiment, the right graph of FIG. 16 can be expressed as an approximated function, y = 2E-06x ³ - 0.0038x ² + 6.2314x + 28.031, And may be stored in the information providing unit 1230. That is, this conversion function is an approximated conversion function between the first driving voltage code and the second driving voltage code.

Here, the right graph may be stored in the code conversion information providing unit 1230 by dividing the first driving voltage code into a plurality of sections, approximating the sections to a plurality of sections, and converting the plurality of conversion functions.

Also, in order to adjust the coefficient value of the transform function, the y-axis is multiplied by a specific value (e.g., 1,000,000) to store the transform function having the simplified coefficients, and the calculation using the transform function is completed, The driving voltage code may be obtained.

The conversion table and the conversion function may correspond to a conversion table and a conversion algorithm for the conversion operation of the code conversion unit 1220 described in the description of FIG.

The conversion table or the conversion function may be acquired by a separate test device and stored in the controller 1210 or may be measured and calculated and stored by the controller 1210 itself.

17 is a diagram showing an embodiment of a conversion table according to an embodiment of the present invention. 18 is a view showing another embodiment of the conversion table according to another embodiment of the present invention.

17, a first driving voltage code obtained based on the right graph of FIG. 16 and a second driving voltage code for matching the first driving voltage code and the diopter with each other are matched to each other, An example is shown.

As shown in Fig. 11, the second drive voltage code representing the same drive voltage to diopter as the first drive voltage code (0, 1, 2) is (0, 4, 8). However, in the conversion table of Fig. 17, the first drive voltage code (0, 1, 2) matches the second drive voltage code (0, 6, 12).

In the interval (0 to 5) of the first drive voltage code, the interval of the second drive voltage code is 6 or 7, while in the interval of 1018 to 1023 of the first drive voltage code, Can be 3 or 4.

This is because the diopter of the liquid interface is proportional to the square of the corresponding driving voltage and the conversion table uses the relationship between the first driving voltage code and the second driving voltage so that the amount of change of the second driving voltage code decreases as the first driving voltage code rises By matching the voltage code, it is possible to control the first driving voltage code and the diopter of the liquid interface to have a linear relationship.

In other words, the variation amount of the average driving voltage in the first range of the first driving voltage code may be larger than the variation amount of the average driving voltage in the second range of the first driving voltage code. Here, the second range may have a lower limit value (or a minimum value) larger than the upper limit value (or the maximum value) of the first range. And, the second range may have the same code range as the first range (i.e., the size of the code obtained by subtracting the lower limit value from the upper limit value of each of the first range or the second range).

For example, as shown in Fig. 17, the change amount of the average drive voltage (6.2 (average drive voltage code change amount) * 0.01125 in the first range (0 to 5) of the first drive voltage code ) = 0.06975) may be larger than the change amount of the average drive voltage (5.2 * 0.01125 = 0.0585) in the second range 1018 to 1023 of the first drive voltage code.

If the second range is a code range that is not the same as the first range, a value obtained by dividing the variation amount of the average driving voltage in the first range by the first range means a variation amount of the average driving voltage in the second range, Which may be greater than the value divided by.

Referring to FIG. 18, a first driving voltage code obtained based on the right graph of FIG. 16, a driving voltage code for the first through fourth driving electrodes that make the first driving voltage code and the diopter have a linear relationship , Driving voltage code for each electrode corresponding to each of the four individual electrodes) are matched with each other.

In the conversion table of FIG. 17, the first driving voltage code and the second driving voltage code are matched. In the conversion table of FIG. 18, the first driving voltage code and the driving voltage code 10 for each of the first to fourth driving electrodes Bit resolution) are directly matched.

In principle, the driving voltage code determining unit 1240 must determine a driving voltage code corresponding to each driving electrode based on the second driving voltage code, but according to the conversion table of FIG. 18, this process may be omitted.

17 and 18 are merely illustrative, and from the first driving voltage code, the conversion table for each of the first to fourth driving electrodes, which compensates for the linear relationship between the first driving voltage code and the diopter of the liquid interface, A conversion table capable of obtaining a driving voltage code suffices.

19 is a view for explaining an application example of a driving voltage applying method according to an embodiment of the present invention.

Referring to FIG. 19, a process of the controller 1210 receiving a first driving voltage code 320 and transmitting a driving voltage code for each electrode to the voltage driver 1250 is shown.

When the code converter 1220 receives the first drive voltage code 320, it performs a conversion operation with reference to the code conversion information providing unit 1230. At this time, a conversion table or a conversion algorithm (or a conversion function) can be used, but in the example of Fig. 19, it is assumed that the conversion table corresponding to Fig. 17 is used.

The code converter 1220 may convert the first driving voltage code 320 of the 320 into the second driving voltage code of 1663 by referring to the conversion table, and may transmit the converted second driving voltage code to the driving voltage code determining unit 1240.

The driving voltage code determination unit 1240 can determine the driving voltage code for each electrode based on the second driving voltage code. For example, as shown in FIG. 19, the driving voltage code determination unit 1240 may calculate the quotient 415 and the remainder (3) by dividing the second driving voltage code 1663 by 4, which is the number of electrodes. Here, the quotient 415 is the basic driving voltage code, and the remaining (3) means the number of electrodes to which the driving voltage code higher by one than the basic driving voltage code is to be delivered. The basic driving voltage code can be transmitted to the other electrodes except for this electrode.

Therefore, the driving voltage code determination unit 1240 determines a driving voltage code of 416 for the first to third driving electrodes and a driving voltage code of 415 for the fourth driving electrode, and transmits the determined driving voltage code to the voltage driver 1250 have. That is, the driving voltage codes for the electrodes corresponding to the first to fourth driving electrodes determined according to the partial code among the second driving voltage codes may not be equal to each other.

6, when the positions of the first to fourth driving electrodes to which a higher driving voltage is applied are to be different for each sub-cycle, the driving voltage code determining unit 1240 determines the driving voltage The position of the electrode to which the code is applied may be controlled differently for each sub-cycle.

As described above, the operation of the drive voltage code determination unit 1240 may be performed in advance, and may be omitted when the conversion table of FIG. 18 is stored in the code conversion information providing unit 1230.

In this specification, four driving electrodes are described. However, the scope of the present invention is not limited to this, and may be applied to the case where eight driving electrodes exist. Of course, in this case, the first driving voltage code of 10 bits may be matched to the second driving voltage code of 13 bits, so that the linear relationship between the first driving voltage code and the liquid interface may be finely controlled.

FIGS. 20 and 21 are diagrams for explaining the effect of the driving voltage applying method according to the embodiment of the present invention.

Referring to FIG. 20, the left graph shows the diopter mean of 42 liquid lenses for a 10-bit first drive voltage code when the controller 1210 does not perform a conversion operation of the first drive voltage code.

In the right graph, the first driving voltage code and the diopter are linearly related to each first driving voltage code through normalization, scale conversion, inverse function conversion, scale conversion, and coefficient value adjustment using the graph between the first driving voltage code and the diopter average 12-bit linear code is obtained. As shown in the left graph, since the first driving voltage code of about 880 or more shows a tendency different from the first driving voltage code of 880 or less, the second driving voltage code (0 to 880) . It is assumed that a condition that the dioptric control range required by the system can be satisfied even if only the first driving voltage code (0 to 880) is used is assumed, and it is assumed that this condition is assumed. If diopter control using a first driving voltage code of about 880 or more is required, the first driving voltage code is divided into a plurality of sections as described in Fig. 16, approximated for each of a plurality of sections, And may be stored in the information providing unit 1230.

Equal ^{3560.2x 2 + 6E + 06x + 6E} + 07 - first drive voltage codes (0 to 880) and the transfer function is obtained by approximating the relationship between the 12-bit linear code y = 1.301x ^3. The conversion function may be stored in the code conversion information providing unit 1230.

Referring to FIG. 21, the graph on the left shows the change in diopter when the drive voltage is applied to the first to fourth drive electrodes as it is without changing the first drive voltage code of the controller 1210 for 42 liquid lenses to be.

However, in the right graph, the controller 1210 refers to the code conversion information providing unit 1230 that stores the conversion function for the 42 liquid lenses, and controls the controller 1210 to perform the driving corresponding to the second driving voltage code And a diopter change when a voltage is applied to the first to fourth driving electrodes.

When the left graph and the right graph are compared, it can be seen that the first driving voltage code and the diopter have a linear relationship in the first driving voltage code (0 to 880).

Accordingly, the controller 1210 or an external application processor or the like can intuitively control the diopter using the linear relationship between the first driving voltage code and the diopter.

When the linear relationship is secured, the application obtains the lower limit value and the upper limit value of the first driving voltage code together with the diopter value matched with the lower limit value and the upper limit value, and obtains the diopter value between the lower limit value and the upper limit value of the first driving voltage code It is possible to calculate a diopter value corresponding to an arbitrary code, which can greatly improve the optical performance of the liquid lens.

The linear relationship referred to in this specification may mean a linear relationship between the diopter of the liquid lens itself and the first driving voltage cord but is not limited thereto and may be a linear relationship between the diopter of the entire optical system including the liquid lens and the first driving voltage cord .

According to the driving voltage applying method according to the embodiment of the present invention, the linear relationship between the driving voltage code and the diopter at the interface of the liquid lens can be secured by converting the driving voltage code using the driving voltage code having higher resolution.

The liquid lens according to an embodiment of the present invention includes a cavity, a conductive liquid and a nonconductive liquid disposed in the cavity, and n individual electrodes (n is an integer of 2 or more) and a common electrode, Wherein an interface is formed between the liquid and the nonconductive liquid, the first driving voltage code determining the average driving voltage and the diopter of the interface have a linear relationship, and as the first driving voltage code is sequentially changed, The driving voltage is irregularly changed and the average driving voltage may be an average voltage of each driving voltage applied between the common electrode and each of the n individual electrodes.

While only a few have been described above with respect to the embodiments, various other forms of implementation are possible. The technical contents of the embodiments described above may be combined in various forms other than the mutually incompatible technologies, and may be implemented in a new embodiment through the same.

The above-described liquid lens may be included in the camera module. The camera module includes a lens assembly including a liquid lens mounted on a housing and at least one solid lens that can be disposed on a front surface or a rear surface of the liquid lens, an image sensor that converts an optical signal transmitted through the lens assembly into an electrical signal, And a control circuit for supplying a driving voltage to the liquid lens.

While only a few have been described above with respect to the embodiments, various other forms of implementation are possible. The technical contents of the embodiments described above may be combined in various forms other than the mutually incompatible technologies, and may be implemented in a new embodiment through the same.

For example, an optical device (optical device) including a camera module including the above-described liquid lens can be implemented. Here, the optical device may include a device capable of processing or analyzing an optical signal. Examples of optical devices include camera / video devices, telescope devices, microscope devices, interferometer devices, photometer devices, polarimeter devices, spectrometer devices, reflectometer devices, autocollimator devices, lens meter devices, The embodiment of the present invention can be applied to an optical device that can be used. In addition, the optical device can be implemented as a portable device such as a smart phone, a notebook computer, and a tablet computer. Such an optical apparatus may include a camera module, a display unit for outputting an image, and a main body housing for mounting the camera module and the display unit. The optical device may further include a memory unit in which a communication module capable of communicating with other devices can be mounted on the body housing and can store data.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

Claims (12)

A conductive liquid and a nonconductive liquid disposed in the cavity, and n individual electrodes (n is an integer of 2 or more) and a common electrode,
An interface is formed between the conductive liquid and the nonconductive liquid,
The variation amount of the average driving voltage in the first range of the first driving voltage code is larger than the variation amount of the average driving voltage in the second range of the first driving voltage code,
Wherein the average driving voltage is an average voltage of each driving voltage applied between the common electrode and each of the n individual electrodes,
The lower limit value of the second range is larger than the upper limit value of the first range,
Wherein the first driving voltage code is a value corresponding to the average driving voltage. And a conductive liquid and a non-conductive liquid disposed in the cavity, and a common electrode, wherein n is an integer of 2 or more, and n is an integer greater than or equal to 2, and a liquid in which an interface is formed between the conductive liquid and the non- lens; And
And a control circuit which generates driving voltages to be applied between any one of the common electrode and the n individual electrodes of the liquid lens,
The variation amount of the average driving voltage in the first range of the first driving voltage code is larger than the variation amount of the average driving voltage in the second range of the first driving voltage code,
Wherein the average driving voltage is an average voltage of each driving voltage applied between the common electrode and each of the n individual electrodes,
The lower limit value of the second range is larger than the upper limit value of the first range,
Wherein the first drive voltage code is a value corresponding to the average drive voltage. 3. The method of claim 2,
The control circuit comprising:
A code conversion unit for receiving the first driving voltage code and converting the first driving voltage code into a second driving voltage code having a higher resolution than the first driving voltage code; And
And a code conversion information providing unit having a conversion table or a conversion algorithm for converting the first drive voltage code into the second drive voltage code. The method of claim 3,
The control circuit comprising:
And a voltage driver for generating the respective driving voltage based on the converted second driving voltage code. The method of claim 3,
Wherein the conversion table is a table in which the first driving voltage code and the second driving voltage code are matched with each other to correct the first driving voltage code and the diopter of the interface to have a linear relationship. 6. The method of claim 5,
The control circuit comprising:
And a driving voltage code determining unit for determining driving voltage codes for the electrodes corresponding to the first to nth driving electrodes in accordance with the second driving voltage code. The method of claim 3,
Wherein the conversion table is configured to match the first driving voltage code and the driving voltage code for each electrode corresponding to each of the n individual electrodes to each other so as to correct the first driving voltage code and the diopter of the interface to have a linear relationship, A table, a camera module. The method of claim 3,
Wherein the conversion algorithm is a conversion function between the first drive voltage code and the second drive voltage code to correct the first drive voltage code and the diopter of the interface to have a linear relationship. The method of claim 3,
Wherein at least two driving voltage cords of the driving voltage cords corresponding to the n individual electrodes are different from each other. The method of claim 3,
Wherein the conversion table or the conversion algorithm is configured to determine from the relationship between the first driving voltage code and the diopter of the interface at least one of normalization, scale conversion, and inverse function conversion that the diopter of the first driving voltage code and the interface is linear The camera module being determined to have a relationship. A conductive liquid and a nonconductive liquid disposed in the cavity, and n individual electrodes (n is an integer of 2 or more) and a common electrode,
An interface is formed between the conductive liquid and the nonconductive liquid,
The first driving voltage code for determining the average driving voltage and the diopter of the interface have a linear relationship,
As the first drive voltage code is sequentially changed, the average drive voltage is changed irregularly,
Wherein the average driving voltage is an average voltage of each driving voltage applied between the common electrode and each of the n individual electrodes. A camera module according to claim 2;
A display unit for outputting an image;
A battery for supplying power to the camera module; And
And a housing for mounting the camera module, the display unit, and the battery.

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