KR102376689B1 - Camera module including liquid lens and optical apparatus - Google Patents

Abstract

A camera module according to an embodiment of the present invention includes: a first plate having a cavity for accommodating a conductive liquid and a non-conductive liquid; an electrode part disposed on the first plate and including first and second electrodes electrically connected to an external power source to change an interface between the conductive liquid and the non-conductive liquid; an insulating part disposed on the electrode part and blocking contact with the non-conductive liquid; and a liquid lens comprising a controller for controlling the voltage applied to the electrode part; an image sensor generating an auto-focusing control signal for controlling a focal length of the liquid lens; and a control circuit generating a driving voltage applied to the first electrode and the second electrode according to the auto-focusing control signal.

Description

CAMERA MODULE INCLUDING LIQUID LENS AND OPTICAL APPARATUS

The present invention relates to a camera module and an optical device comprising a liquid lens. More specifically, the present invention relates to a camera module and an optical device including a liquid lens capable of adjusting a focal length using electrical energy.

Users of portable devices want optical devices with high resolution, small size, and various shooting functions (such as auto-focusing (AF) function, image stabilization or optical image stabilization (OIS) function). . Such a photographing function may be implemented through a method of directly moving a lens by combining a plurality of lenses, but if the number of lenses is increased, the size of the optical device may increase.

Autofocus and image stabilization are performed by moving or tilting multiple lens modules fixed to the lens holder and aligned with the optical axis in the vertical direction of the optical axis or optical axis, and driving a separate lens to drive the lens module device is used. However, the lens driving device consumes high power, and in order to protect it, a cover glass must be added separately from the camera module, so the overall thickness is increased.

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

An object of the present invention is to provide a method for applying a driving voltage of a liquid lens, a liquid lens, a camera module, and an optical device.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. will be able

A camera module according to an embodiment of the present invention includes: a first plate having a cavity for accommodating a conductive liquid and a non-conductive liquid; an electrode part disposed on the first plate and including first and second electrodes electrically connected to an external power source to change an interface between the conductive liquid and the non-conductive liquid; an insulating part disposed on the electrode part and blocking contact with the non-conductive liquid; and a liquid lens comprising a controller for controlling the voltage applied to the electrode part; an image sensor generating an auto-focusing control signal for controlling a focal length of the liquid lens; and a control circuit generating a driving voltage applied to the first electrode and the second electrode according to the auto-focusing control signal.

In an exemplary embodiment, the image sensor may include: a phase difference detection pixel outputting a first light amount distribution and a second light amount distribution; and an auto-focusing control unit configured to generate the auto-focusing control signal by comparing the first light quantity distribution and the second light quantity distribution.

In an embodiment, the phase difference detection pixel may include: a first pixel including a plurality of pixels each having a light blocking layer on the right side of the light receiving area and arranged in the same row, and outputting the first light quantity distribution; and a second pixel each including a light blocking layer on the left side of the light receiving area, a plurality of pixels arranged in the same row, and outputting the second light amount distribution.

According to an embodiment, the auto-focusing control unit may include, when a sign of a result of subtracting a pixel number corresponding to the center of the second light quantity distribution from a pixel number corresponding to the center of the first light quantity distribution is negative, the liquid lens It is possible to generate an auto-focusing control signal that controls to decrease the focal length of the .

According to an embodiment, the auto-focusing control unit may include, when a sign of a result of subtracting a pixel number corresponding to the center of the second light quantity distribution from a pixel number corresponding to the center of the first light quantity distribution is a positive number, It is possible to generate an auto-focusing control signal that controls to increase the focal length.

According to an embodiment, the auto-focusing control unit may include, when a result of subtracting a pixel number corresponding to the center of the second light quantity distribution from a pixel number corresponding to the center of the first light quantity distribution is 0, the focus of the liquid lens It is possible to generate an auto-focusing control signal that controls the distance to be maintained.

According to an embodiment, the auto-focusing control signal may include information about a number having a sign.

According to an embodiment, the control circuit may include: a controller configured to determine a driving voltage code according to the auto-focusing control signal; and a voltage driver configured to generate the driving voltage supplied to the plurality of electrode sectors of the first electrode and the electrode sectors of the second electrode according to the driving voltage code.

According to an embodiment, the controller determines a variable direction and a variable amount of a focal length based on a relationship between the autofocusing control signal and a focal length of the liquid lens, and based on the variable direction and variable amount of the focal length A new driving voltage code corresponding to the variable direction and variable amount of the focal length may be determined by referring to the driving voltage table.

According to an embodiment, the driving voltage table may include information obtained by mapping the driving voltage code and a focal length of the liquid lens.

A camera module according to another embodiment of the present invention includes: a liquid lens including a first electrode and a second electrode for receiving a driving voltage for changing an interface between a conductive liquid and a non-conductive liquid; an image sensor generating an auto-focusing control signal for controlling a focal length of the liquid lens; and a control circuit generating a driving voltage applied to the first electrode and the second electrode according to the auto-focusing control signal.

An optical device according to an embodiment of the present invention, the camera module; and a battery for supplying power to the camera module.

Aspects of the present invention are only some of the preferred embodiments of the present invention, and various embodiments in which the technical features of the present invention are reflected are detailed descriptions of the present invention that will be described below by those of ordinary skill in the art can be derived and understood based on

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

According to the camera module and optical device including the liquid lens according to an embodiment of the present invention, by detecting whether the current focal length is abnormal, and adjusting the focal length of the liquid lens using the detection result, auto for the liquid lens A focusing function can be implemented.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs 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 a camera module.
FIG. 3 is a block diagram schematically illustrating the camera module shown in FIG. 1 .
4 illustrates a liquid lens whose interface is adjusted in response to a driving voltage.
FIG. 5 is a diagram schematically illustrating the phase difference detection pixel of FIG. 3 .
6 is a diagram illustrating an embodiment in which phase difference detection pixels are arranged.
7 is a view for explaining an operation of generating an auto-focusing control signal based on a first light amount distribution and a second light amount distribution of a phase difference detection pixel.

Hereinafter, an embodiment will be described in detail with reference to the accompanying drawings. Since the embodiment may have various changes and may have various forms, specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the embodiment to a specific disclosed form, and it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the embodiment.

Terms such as “first” and “second” may be used to describe various elements, but the elements should not be limited by the terms. These terms are used for the purpose of distinguishing one component from another. In addition, terms specifically defined in consideration of the configuration and operation of the embodiment are only for describing the embodiment, and do not limit the scope of the embodiment.

In the description of the embodiment, in the case where it is described as being formed in "up (up)" or "below (on or under)" of each element, on (on or under) ) includes both elements in which two elements are in direct contact with each other or one or more other elements are disposed between the two elements indirectly. In addition, when expressed as “up (up)” or “down (on or under)”, the meaning of not only the upward direction but also the downward direction based on one element may be included.

Also, as used hereinafter, relational terms such as "upper/upper/above" and "lower/lower/below" etc. do not necessarily require or imply any physical or logical relationship or order between such entities or elements, It 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 at least one of 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 part. 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 an interface between the conductive liquid and the non-conductive liquid by applying a voltage. The liquid lens may further include an insulating layer disposed on the electrode part to block contact between the electrode and the non-conductive 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 lens assembly 22 may include a plurality of lenses. The lens assembly 22 may include a plurality of lenses including a liquid lens, and a focal length of the liquid lens may be adjusted in response 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 an individual electrode, and the second electrode may be a conductive metal plate or a common electrode.

The camera module 10 may include a lens assembly 22 including a plurality of circuits 24 and 26 and a plurality of lenses disposed on one printed circuit board (PCB), but this is only one example. However, it does not limit the scope of the invention. The configuration of the control circuit 24 may be designed differently according to specifications required for an optical device in which the camera module 10 is mounted. In particular, in order to reduce the size of the operating voltage applied to the lens assembly 22 , the control circuit 24 may be implemented as a single chip. Accordingly, the size of the optical device mounted on the portable device may be further reduced.

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

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

Referring to FIG. 2 , the lens assembly 22 may include at least one of a first lens unit 100 , a second lens unit 150 , a liquid lens 300 , a holder 400 , and a connection unit 500 . there is.

There may be one or two or more connections. For example, in the case of having one connection part, a part of the connection part is disposed on the upper or lower part of the liquid lens 300 to be connected to the liquid lens 300, and when it has two connection parts, it is connected to the upper part of the liquid lens 300 It may include a first connection part and a second connection part connected to the lower portion of the liquid lens. One end of the connection part may be disposed under the lens assembly 22 , and may be electrically connected to a substrate on which the image sensor is mounted and the image sensor 26 is disposed. The illustrated structure of the lens assembly 22 is only one example, and the structure of the lens assembly 22 may vary according to specifications required for an optical device. For example, in the illustrated example, the liquid lens 300 is positioned between the first lens unit 100 and the second lens unit 150 , but in other examples, the first lens unit or the second lens unit may be omitted. . In addition, the liquid lens 300 may be located above the first lens unit 100 (front), and the liquid lens 300 may be located below the second lens unit. The liquid lens 300 includes a cavity defined by an aperture area, and in the other example, the liquid lens 300 may be disposed so that the inclination direction of the cavity 310 is opposite. This may mean that, unlike FIG. 2 , the opening area of the cavity 310 in the direction in which the light is incident is narrower than the opening area in the opposite direction. When the liquid lens 300 is disposed so that the inclination direction of the cavity 310 is opposite, all or part of the arrangement of the liquid lens such as the electrode and the liquid may be changed together depending on the liquid lens inclination direction, and the inclination direction of the cavity may be changed and the rest of the batch may not be changed.

The first lens unit 100 is disposed in front of the lens assembly 22 , and is configured to receive light from the outside of the lens assembly 22 . The first lens unit 100 may include 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 150 may be mounted on the holder 400 . In this case, a through hole may be formed in the holder 400 , and the first lens unit 100 and the second lens unit 150 may be disposed in the through hole. In addition, the liquid lens 300 may be inserted into a space between the first lens unit 100 and the second lens unit 150 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 can be exposed to the outside by protruding to the outside of the holder 400 . 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. In order to prevent or suppress damage to the surface of the exposure lens 110 , a method of disposing a cover glass or forming a coating layer or configuring the exposure lens 100 with a wear-resistant material to prevent surface damage may be applied.

The second lens unit 150 is disposed behind the first lens unit 100 and the liquid lens 300 , and light incident to the first lens unit 100 from the outside passes through the liquid lens unit 300 . It may enter the second lens unit 150 . The second lens unit 150 may be spaced apart from the first lens unit 100 and disposed in a through hole formed in the holder 400 .

Meanwhile, the second lens unit 150 may include at least one lens, and when two or more lenses are included, the optical system may be formed by aligning the second lens unit 150 with respect to the central axis PL.

The liquid lens 300 is disposed between the first lens unit 100 and the second lens unit 150 , and may be inserted into the insertion hole 410 of the holder 400 . The liquid lens 300 may also be aligned with respect to the central axis PL, like the first lens unit 100 and the second lens unit 150 . One or at least two insertion holes 410 of the holder 400 may be formed on the side of the holder 400 . The liquid lens may be disposed in the insertion hole 410 . The liquid lens may be disposed to protrude to the outside of the insertion hole 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 transmits, and at least a portion thereof may include a liquid. For example, the cavity 310 may contain two types, namely, a conductive liquid and a non-conductive liquid (or an insulating liquid), and the conductive liquid and the non-conductive liquid may form an interface without mixing with each other. The interface between the conductive liquid and the non-conductive liquid may be deformed by the driving voltage applied through the connection part 500 to change the curvature and/or focal length of the liquid lens 300 . When the deformation of the boundary surface and the change in curvature are controlled, the liquid lens 300 and the lens assembly 22 and the optical device including the same are auto-focusing (Auto-Focusing; AF) function, hand shake correction or image stabilizer (Optical Image Stabilizer) , OIS) functions, and the like.

FIG. 3 is a block diagram schematically illustrating the camera module shown in FIG. 1 .

Referring to FIG. 3 , the control circuit 210 , the lens assembly 250 , and the image sensor 290 included in the camera module 200 are illustrated, and the control circuit 210 , the lens assembly 250 and the image sensor are shown. Each of 290 may correspond to the control circuit 24 , the lens assembly 22 , and the image sensor 26 of FIG. 1 .

The control circuit 210 may include a controller 220 and a connector (not shown).

The control unit 220 is a configuration for performing the AF function and the OIS function, and a user's request or detection result (eg, a motion signal of the gyro sensor 225 , an auto-focusing control signal (AFC) of the image sensor 290 , etc.) can be used to control the liquid lens 280 included in the lens assembly 250 .

The controller 220 may include a controller 230 and a voltage driver 235 . The gyro sensor 225 may be separate from the controller 220 , and the controller 220 may further include a gyro sensor 225 .

The gyro sensor 225 may detect an angular velocity of movement in two directions of a yaw axis and a pitch axis in order to compensate for hand shake in vertical and horizontal directions of the optical device. The gyro sensor 225 may generate a motion signal corresponding to the sensed angular velocity and provide it to the controller 230 .

The controller 230 removes a high-frequency noise component from a motion signal using a low-pass filter (LPF) to implement the OIS function, extracts only a desired band, and uses the noise-removed motion signal to shake hand. In order to calculate the amount and compensate for the calculated amount of hand shake, a driving voltage corresponding to the shape that the liquid lens 280 of the liquid lens module 260 should have may be calculated.

The controller 230 may receive information for an AF function from an optical device or an image sensor 290 or an external (eg, distance sensor), and a liquid lens according to a focal length for focusing on the object through the information. A driving voltage corresponding to the shape that 280 should have may be calculated. The information for the AF function may include an auto focusing control signal AFC generated by the image sensor 290 . The auto-focusing control signal AFC may be a signal controlling whether to maintain, decrease, or increase the current focal length.

The auto-focusing control signal AFC may be a signed number. For example, when the auto-focusing control signal AFC is -3, the auto-focusing control signal AFC may be a signal for controlling to reduce the current focal length by a magnitude corresponding to 3 . When the auto-focusing control signal AFC is +5, the auto-focusing control signal AFC may be a signal for controlling to increase the current focal length by a magnitude corresponding to 5. Also, when the auto-focusing control signal AFC is 0, the auto-focusing control signal AFC may be a signal for controlling the current focal length to be maintained. The auto-focusing control signal AFC may be implemented as a digital code, and any one bit of the digital code represents a sign and the remaining bits represent an absolute value, thereby representing a signed number.

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, and convert the driving voltage code corresponding to the calculated driving voltage to the driving voltage. It can be obtained by referring to the table.

The controller 230 may adjust the current focal length of the liquid lens 280 according to the auto-focusing control signal AFC. The controller 230 may store information on the relationship between the auto-focusing control signal AFC and the focal length in advance, and the driving voltage table may include information obtained by mapping a driving voltage code and a focal length. When receiving the auto-focusing control signal AFC, the controller 230 may determine a driving voltage code corresponding to a focal length corresponding to the auto-focusing control signal AFC by referring to the driving voltage table.

According to another embodiment, the controller 230 may adjust the current diopter of the liquid lens 280 according to the auto-focusing control signal AFC. The controller 230 may store information on the relationship between the auto-focusing control signal AFC and the diopter in advance, and the driving voltage table may include information obtained by mapping the driving voltage code to the diopter. When receiving the auto-focusing control signal AFC, the controller 230 may determine a driving voltage code corresponding to a diopter corresponding to the auto-focusing control signal AFC by referring to the driving voltage table. Here, the focal length and the diopter are in an inverse relation to each other, and adjusting any one of the focal length and the diopter has substantially the same meaning as adjusting the other. do.

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

The voltage driver 235 receives a supply voltage (eg, a voltage supplied from a separate power circuit) and increases the voltage level. Each of a voltage stabilizer and liquid lens 280 for stabilizing the output of the voltage booster A switching unit for selectively supplying an output of the voltage booster to a terminal may be included.

Here, the switching unit may include a configuration of a circuit called an H bridge. The high voltage output from the voltage booster is applied as a power supply voltage of the switching unit. The switching unit may selectively supply the applied power voltage and 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, and both ends of the liquid lens 280 are connected to the first electrode and It may mean a second electrode. Also, both ends of the liquid lens 280 may refer to any one of four electrode sectors of the first electrode and one electrode sector of the second electrode.

A voltage in the form of a pulse having a preset width may be applied to each electrode sector of the liquid lens 280 , and the driving voltage applied to the liquid lens 280 is the difference between the voltages applied to each of the first electrode and the second electrode. am. Here, a voltage applied to each electrode sector of the first electrode may be defined as an individual voltage, and a voltage applied to the second electrode may be defined as a common voltage.

That is, in order for the voltage driver 235 to control the driving voltage applied to the liquid lens 280 according to the digital driving voltage code provided from the controller 230 , the voltage booster controls the increased voltage level, The switching unit generates an analog driving voltage corresponding to the driving voltage code by controlling the phases of the pulse voltages applied to the individual electrodes and the common electrode.

The control circuit 210 may further include a connector (not shown) performing a function of communication or an interface of the control circuit 210 . For example, for communication between the control circuit 210 using the Inter-Integrated Circuit (I²C) communication method and the lens assembly 250 using the Mobile Industry Processor Interface (MIPI) communication method, the connector performs communication protocol conversion. can be done

In addition, the connector may receive power from an external (eg, 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 providing unit 270 and a liquid lens 280 .

The driving voltage providing unit 270 may receive a driving voltage (an analog voltage corresponding to four individual electrodes and one common electrode) from the voltage driver 235 to provide the driving voltage to the liquid lens 280 . The driving voltage providing unit 270 may include a voltage adjusting circuit or a noise removing circuit for compensating for a loss due to the terminal connection between the control circuit 210 and the lens assembly 250, or bypassing the output voltage. bypass) is also possible.

The driving voltage driver 270 may be disposed on a flexible printed circuit board (FPCB, or a first board) constituting at least a part of the connection part 500 of FIG. 2 , but the scope of the present invention is not limited thereto. The connection unit 500 may include a driving voltage providing unit 270 .

The liquid lens 280 may perform an AF function or an OIS function by deforming the interface between the conductive liquid and the non-conductive liquid according to the driving voltage.

The image sensor 290 includes a pixel array that receives the optical signal passing through the lens assembly 250 and converts it into an electrical signal corresponding to the optical signal, a driving circuit that drives a plurality of pixels included in the pixel array, and It may include a readout circuit for reading a pixel signal, and an image processor for processing (eg, interpolation, frame synthesis, etc.) the pixel signal.

The image sensor 290 according to an embodiment of the present invention may further include a phase difference detection pixel 294 and an auto-focusing controller 292 .

The phase difference detection pixel 294 may output a first light amount distribution and a second light amount distribution that are the basis of the auto-focusing control signal AFC. The phase difference detection pixel 294 may be implemented as a part of the pixel array, or may be implemented independently of the pixel array. In addition, the phase difference detection pixel 294 may be driven and read by the driving circuit and the read-out circuit, or may include a driving circuit and a read-out circuit separate from the driving circuit and the read-out circuit. .

The auto focusing control unit 292 compares the first light quantity distribution and the second light quantity distribution of the phase difference detection pixel 294 to determine the direction and degree of varying the current focal length or to control to maintain the current focal length. A focusing control signal AFC may be generated.

Detailed operations of the phase difference detection pixel 294 and the auto-focusing control unit 292 will be described later with reference to FIGS. 5 to 7 .

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

First, referring to (a), the liquid lens 28 whose interface is adjusted in response to a driving voltage is disposed in four different directions with the same angular distance, and a plurality of electrode sectors L1 and L2 constituting the first electrode , L3, L4) and an electrode sector constituting the second electrode may receive a driving voltage. When a driving voltage is applied through the plurality of electrode sectors L1 , L2 , L3 , and L4 constituting the first electrode and the electrode sectors constituting the second electrode, the interface between the conductive liquid and the non-conductive liquid disposed in the cavity 310 . This can be transformed. The degree and shape of the deformation of the interface between the conductive liquid and the non-conductive liquid may be controlled by the controller 230 to implement the AF function or the OIS function.

Also, referring to (b), one side of the lens 28 receives voltages from different electrode sectors L1, L2, L3, and L4, and the other side is connected to the electrode sector C0 of the second electrode. It can be described as a plurality of capacitors 30 to which voltage is applied.

In the present specification, four individual electrodes are described as an example, but the scope of the present invention is not limited thereto.

FIG. 5 is a diagram schematically illustrating the phase difference detection pixel 294 of FIG. 3 . 6 is a diagram illustrating an embodiment in which the phase difference detection pixels 294 are arranged. 7 is a diagram for explaining an operation of generating an auto-focusing control signal based on a first light amount distribution and a second light amount distribution of the phase difference detection pixel 294 .

5 to 7 , the phase difference detection pixel 500 illustrates one embodiment of any one phase difference detection pixel included in the phase difference detection pixel 294 illustrated in FIG. 3 .

The phase difference detection pixel 500 may include at least one of a micro lens 510 , a color filter 520 , a photodiode 530 , and a light blocking layer 540 .

The micro lens 510 is disposed above the phase difference detection pixel 500 (in the direction in which the lens assembly 22 is located), and may increase light gathering power.

The color filter 530 is disposed under the microlens 520 and has a specific wavelength of light (eg, red, green, blue, magenta, yellow, cyan). (Cyan)) can be selectively permeated.

The photodiode 530 may accumulate photocharges generated according to the intensity of the incident light passing through the microlens 510 . The photocharge accumulated in the photodiode 530 may be converted into an electric signal by a driving circuit and a readout circuit and transmitted to the auto-focusing controller 292 as a pixel signal of the phase difference detection pixel 500 .

The light blocking layer 540 may block light incident to at least a portion of the light receiving area corresponding to the micro lens 510 . For example, the light blocking layer 540 may block light incident to an area corresponding to a half of the light receiving area.

As shown in FIG. 5 , the light blocking layer 540 is disposed on the right side of the phase difference detection pixel 500 to pass the light L1 incident to the left of the light receiving area and light L2 incident to the right of the light receiving area. can be blocked.

Referring to FIG. 6 , a part of a pixel array is shown. A pixel having a light blocking layer 540 disposed on the right side of the light receiving area is defined as a first pixel, and a pixel having a light blocking layer 540 disposed on the left side of the light receiving area. is defined as a second pixel. The first pixel and the second pixel may be disposed in different rows of the pixel array. As shown in FIG. 6 , one row may be disposed between the first pixel and the second pixel, but the scope of the present invention is not limited thereto, and the first pixel and the second pixel may be consecutively disposed or the first pixel and the second pixel A plurality of rows may be disposed between pixels.

The first pixel may include pixels 1 to 9 arranged in the same row, and the second pixel may also include pixels 1 to 9 arranged in the same row.

The k-th pixel of the first pixel (k is an integer between 1 and 9) may be disposed in the same column as the k-th pixel of the second pixel.

Pixels 1 to 9 of the first pixel and pixels 1 to 9 of the second pixel may be sequentially disposed. According to another embodiment, they may be arranged at regular or non-constant intervals. In this case, a first pixel and a second pixel may be disposed between pixels for generating image data.

It is only an example that each of the first pixel and the second pixel includes nine pixels, and it is also possible to include fewer or more pixels.

Referring to FIG. 7 , light passing through the liquid lens 700 may be focused at an arbitrary position based on a pixel array in which the phase difference detection pixel 500 is disposed. 7 exemplifies a case in which the focus is focused on the focus 1 to the focus 3, and when the focus is focused on the focus 2 because the pixel array is located in the focus 2, it is assumed that the focus is a normal focal length.

Focus 1 may indicate a case in which the front of the pixel array is focused (ie, a long focal length), and focus 3 may indicate a case in which the rear of the pixel array is focused (ie, a short focal length).

Light passing through the liquid lens 700 may be incident to the first pixel and the second pixel disposed in the pixel array. Among the cavities of the liquid lens 700 , the light passing through the left with respect to the optical axis is guided to the first pixel having the light blocking layer 540 on the right, and the light passing through the right with respect to the optical axis among the cavities of the liquid lens 700 . The silver light blocking layer 540 may be guided to the second pixel provided on the left side.

On the right side of FIG. 7 , the distribution of the amount of light appearing in the first pixel and the second pixel according to the focus to be focused is shown. A light quantity distribution appearing in the first pixel is defined as a first light quantity distribution, and a light quantity distribution appearing in the second pixel is defined as a second light quantity distribution. The first light quantity distribution or the second light quantity distribution means a set of pixel signals output by nine pixels included in the first pixel or the second pixel, or the auto-focusing control unit 292 interpolates the pixel signals to It may mean continuous data obtained.

And, in the graph including the first light quantity distribution and the second light quantity distribution, the X axis indicates the position of the pixel, that is, the pixel number, and the Y axis indicates the size of the light quantity sensed by the pixel.

First, when focus 2 is focused, the first light quantity distribution 730 and the second light quantity distribution 740 have the same shape, and the center of the shape (eg, the pixel position of the inflection point) is the same as pixel 5, respectively. can have a location. Here, since the position of the center of the shape determines the phase, when the focus 2 is focused, the first light quantity distribution 730 and the second light quantity distribution 740 may be in phase with each other. In addition, the same shape may be a concept including a shape having a similarity of more than a certain range as well as a shape that is completely physically identical.

When the focus 1 is focused, the first light quantity distribution 710 and the second light quantity distribution 720 may have the same shape, but the centers of the shapes may have different positions as the 3rd pixel and the 7th pixel, respectively. Here, since the position of the center of the shape determines the phase, when focus 1 is focused, the first light quantity distribution 710 and the second light quantity distribution 720 are out of phase with each other. In this case, focus 1 means a case where the focal length is longer than that of the subject, and the phase of the first light quantity distribution 710 is biased to the left with respect to the central pixel (ie, the 5th pixel), and the second light quantity distribution 720 is The phase is shifted to the right with respect to the central pixel. In addition, the phase difference (four pixels), which is the degree to which the centers of the first light quantity distribution 710 and the second light quantity distribution 720 are displaced from each other, is how far the focal length is from the normal focal length, that is, how much the focal length must be adjusted. can indicate that

When the focus 3 is focused, the first light quantity distribution 750 and the second light quantity distribution 760 have the same shape, but the center of the shape may have different positions with the 7th pixel and the 3rd pixel, respectively. Here, since the position of the center of the shape determines the phase, when focus 3 is focused, the first light quantity distribution 750 and the second light quantity distribution 760 are out of phase with each other. In this case, focus 3 means a case where the focal length is shorter than that of the subject, and the phase of the first light amount distribution 750 is skewed to the right with respect to the central pixel (ie, the 5th pixel), and the second light amount distribution 760 is The phase is shifted to the left with respect to the central pixel. In addition, the phase difference (four pixels), which is the degree to which the centers of the first light quantity distribution 750 and the second light quantity distribution 760 are shifted from each other, is how far the focal length is from the normal focal length, that is, how much the focal length must be adjusted. can indicate that

Accordingly, the auto-focusing control unit 292 detects a phase difference between the first light quantity distribution and the second light quantity distribution based on the first light quantity distribution and the second light quantity distribution, and generates an auto-focusing control signal AFC based on the detected phase difference. can create

According to an exemplary embodiment, the auto-focusing control unit 292 subtracts the pixel number corresponding to the center of the second light quantity distribution from the pixel number corresponding to the center of the first light quantity distribution, and uses the subtraction result to obtain an auto-focusing control signal (AFC) ) can be created. Here, the sign of the subtraction result may determine the direction in which the focal length is varied, and the absolute value of the subtraction result may determine the degree to which the focal length is varied.

For example, when focus is on focus 1, the result of subtraction becomes -4, the sign of the subtraction result is (-), so the focal length is reduced, and since the absolute value of the subtraction result is 4, the focal length is reduced by 4. It can be the basis of the auto-focusing control signal (AFC) that controls the

For example, when focus 2 is focused, the subtraction result becomes 0, and since the subtraction result has no sign and the absolute value is 0, it can be the basis of an auto-focusing control signal (AFC) that controls to maintain the focal length. . According to another embodiment, not only when the subtraction result is 0, but also when it is within a certain threshold range (eg, 0 or more and 1 or less), it may be the basis of an auto-focusing control signal (AFC) that controls to maintain the focal length. .

For example, if focus 3 is focused, the result of subtraction becomes +4. Since the sign of the subtraction result is (+), the focal length is increased. Since the absolute value of the subtraction result is 4, the focal length is increased by 4. It can be the basis of the auto-focusing control signal (AFC) that controls the

When receiving the auto-focusing control signal AFC, the controller 230 may determine the variable direction and variable amount of the focal length based on the relationship between the pre-stored auto-focusing control signal AFC and the focal length. The controller 230 may determine a new driving voltage code corresponding to the variable direction and variable amount of the focal length by referring to the driving voltage table based on the variable direction and variable amount of the focal length.

According to the camera module according to an embodiment of the present invention, an auto-focusing function for the liquid lens can be implemented by detecting whether the current focal length is abnormal and adjusting the focal length of the liquid lens using the detection result.

Hereinafter, the configuration of the camera module according to the present embodiment will be described.

The camera module may include a lens assembly including a liquid lens, an infrared cut filter (not shown), a printed circuit board (not shown), an image sensor (not shown), and a controller (not shown). However, at least one of the infrared cut filter and the control unit in the camera module may be omitted or changed.

The infrared filter may block light in the infrared region from being incident on the image sensor. An infrared filter may be disposed between the lens assembly and the image sensor. The infrared filter may be an infrared absorption filter or an infrared reflection filter. In addition, the infrared filter may be formed by coating or depositing on one side of the liquid lens without separately disposing.

The upper surface of the printed circuit board and the liquid lens may be electrically connected. An image sensor may be disposed on the printed circuit board. The printed circuit board may be electrically connected to the image sensor. For example, a holder member may be disposed between the printed circuit board and the lens assembly. In this case, the holder member may accommodate the image sensor inside. The printed circuit board can supply power (current or voltage) to the liquid lens. Meanwhile, a control unit for controlling the liquid lens may be disposed on the printed circuit board.

Hereinafter, the configuration of the optical device according to the present embodiment will be described.

The optical device is any one of a cell phone, a mobile phone, a smart phone, a portable smart device, a digital camera, a laptop computer, a digital broadcasting terminal, a PDA (Personal Digital Assistants), a PMP (Portable Multimedia Player), and a navigation device can be However, the type of optical device is not limited thereto, and any device for taking an image or photo may be referred to as an optical device.

The optical device may include a main body (not shown), a camera module, and a display unit (not shown). However, in the optical device, any one or more of the main body, the camera module, and the display unit may be omitted or changed.

Although only a few have been described as described above in relation to the embodiments, various other forms of implementation are possible. The technical contents of the above-described embodiments may be combined in various forms unless they are incompatible with each other, and may be implemented in a new embodiment through this.

It is apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit and essential characteristics of the present invention. Accordingly, the above detailed description should not be construed as restrictive in all respects but as exemplary. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are included in the scope of the present invention.

Claims (12)

a first plate having a cavity for accommodating a conductive liquid and a non-conductive liquid;
an electrode part disposed on the first plate and including first and second electrodes electrically connected to an external power source to change an interface between the conductive liquid and the non-conductive liquid;
an insulating part disposed on the electrode part and blocking contact with the non-conductive liquid; and
a liquid lens including a control unit for controlling the voltage applied to the electrode unit;
an image sensor generating an auto-focusing control signal for controlling a focal length of the liquid lens; and
a control circuit for generating a driving voltage applied to the first electrode and the second electrode according to the auto-focusing control signal;
The control circuit is
a controller for calculating a driving voltage corresponding to a shape that the liquid lens should have according to the auto-focusing control signal and determining a driving voltage code matched with the driving voltage,
The image sensor is
a phase difference detection pixel for outputting a first light amount distribution and a second light amount distribution; and
Comprising an auto-focusing control unit for generating the auto-focusing control signal by comparing the first light quantity distribution and the second light quantity distribution,
The phase difference detection pixel is
Each of the 1-1 to 1-Kth (here, K is a positive integer of 2 or more) pixels including the light-shielding layer on the right side of the light-receiving area and arranged in the same first row, and outputting the first light quantity distribution a first pixel array to and
a second pixel array each including a light blocking layer on the left side of the light receiving area and including 2-1 to 2-Kth pixels arranged in the same second row, and outputting the second light quantity distribution;
at least one row is disposed between the first row and the second row;
The 1-k (1≤k≤K) pixel and the 2-kth pixel are arranged in the same column,
The auto-focusing control unit
From the pixel number corresponding to the center of the first light quantity distribution among the 1-1 to 1-K pixels, the pixel number corresponding to the center of the second light quantity distribution among the 2-1 to 2-K pixels A camera module for generating the auto-focusing control signal by subtracting .
camera module.
which is a camera module. delete delete According to claim 1,
The auto-focusing control unit,
When the sign of the result of the subtraction is negative, the camera module generates an auto-focusing control signal for controlling to decrease the focal length of the liquid lens. According to claim 1,
The auto-focusing control unit,
When the sign of the result of the subtraction is a positive number, the camera module generates an auto-focusing control signal for controlling to increase the focal length of the liquid lens. According to claim 1,
The auto-focusing control unit,
When the subtracted result is 0, the camera module generates an auto-focusing control signal for controlling to maintain the focal length of the liquid lens. delete According to claim 1,
The control circuit is
and a voltage driver configured to generate the driving voltage supplied to the plurality of electrode sectors of the first electrode and the electrode sectors of the second electrode according to the driving voltage code. 9. The method of claim 8,
The controller is
A variable direction and a variable amount of a focal length are determined based on the relationship between the auto-focusing control signal and the focal length of the liquid lens, and the focal length is referred to a driving voltage table based on the variable direction and variable amount of the focal length. determining a new driving voltage code corresponding to the variable direction and variable amount of the camera module. 10. The method of claim 9,
The driving voltage table includes information on which the driving voltage code and a focal length of the liquid lens are mapped. a liquid lens comprising a first electrode and a second electrode for receiving a driving voltage for changing an interface between the conductive liquid and the non-conductive liquid;
an image sensor generating an auto-focusing control signal for controlling a focal length of the liquid lens; and
a control circuit for generating a driving voltage applied to the first electrode and the second electrode according to the auto-focusing control signal;
The control circuit is
a controller for calculating a driving voltage corresponding to a shape that the liquid lens should have according to the auto-focusing control signal and determining a driving voltage code matched with the driving voltage,
The image sensor is
a phase difference detection pixel for outputting a first light amount distribution and a second light amount distribution; and
Comprising an auto-focusing control unit for generating the auto-focusing control signal by comparing the first light quantity distribution and the second light quantity distribution,
The phase difference detection pixel is
Each of the 1-1 to 1-Kth (here, K is a positive integer of 2 or more) pixels including the light-shielding layer on the right side of the light-receiving area and arranged in the same first row, and outputting the first light quantity distribution a first pixel array to and
a second pixel array each including a light blocking layer on the left side of the light receiving area and including 2-1 to 2-Kth pixels arranged in the same second row, and outputting the second light quantity distribution;
at least one row is disposed between the first row and the second row;
The 1-k (1≤k≤K) pixel and the 2-kth pixel are arranged in the same column,
The auto-focusing control unit
From the pixel number corresponding to the center of the first light quantity distribution among the 1-1 to 1-K pixels, the pixel number corresponding to the center of the second light quantity distribution among the 2-1 to 2-K pixels A camera module for generating the auto-focusing control signal by subtracting . The camera module of claim 1 or 11;
a display unit for outputting an image;
a battery for supplying power to the camera module; and
An optical device comprising a housing in which the camera module, the display unit, and the battery are mounted.

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