WO2020246772A1

WO2020246772A1 - Device and method for controlling temperature of liquid lens

Info

Publication number: WO2020246772A1
Application number: PCT/KR2020/007144
Authority: WO
Inventors: 장현웅; 문영섭; 박우진
Original assignee: 엘지이노텍(주)
Priority date: 2019-06-03
Filing date: 2020-06-02
Publication date: 2020-12-10
Also published as: KR20200138976A

Abstract

In an embodiment, a temperature control device for controlling the temperature of a liquid lens comprises: a thermistor having a resistance value that varies according to the temperature of the liquid lens; a storage unit for storing the relationship between the resistance value of the thermistor and the temperature of the liquid lens; a temperature sensing unit which senses the resistance value of the thermistor and outputs the sensed resistance value in a digital format; a control unit which calculates the temperature of the liquid lens, corresponding to the digitized resistance value, from the relationship stored in the storage unit, compares the calculated temperature of the liquid lens with a target temperature for the liquid lens, and outputs the comparison result as a control signal; and a lens heating unit for heating the liquid lens in response to the control signal.

Description

Liquid lens temperature control device and method

The embodiment relates to an apparatus and method for controlling temperature of a liquid lens.

Users of portable devices want optical devices that have high resolution, are small in size, and have various shooting functions. For example, various shooting functions include at least one of an optical zoom function (zoom-in/zoom-out), an auto-focusing (AF) function, or an image stabilization or image stabilization (OIS) function. Can mean

In the conventional case, in order to implement the above-described various photographing functions, a method of combining several lenses and directly moving the combined lenses was used. However, if the number of lenses is increased in this way, the size of the optical device may increase.

The AF function and OIS function are performed by moving or tilting several lenses fixed to the lens holder and aligned with the optical axis in the vertical direction of the optical axis or optical axis, and for this purpose, a lens assembly consisting of a plurality of lenses is driven. A separate lens driving device is required. 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, thereby increasing the overall size of the existing camera module. To solve this problem, research on a liquid lens that performs AF and OIS functions by electrically controlling the curvature of the interface between two liquids is being conducted.

In general, a liquid lens generates heat during operation, and when the temperature of the liquid lens changes due to such heat, the diopter of the liquid lens may change and the liquid lens may not operate normally.

The embodiment provides an apparatus and method for controlling a temperature of a liquid lens capable of controlling the temperature of a liquid lens.

The technical problem to be solved in the embodiment is not limited to the technical problem mentioned above, and another technical problem not mentioned will be clearly understood by those of ordinary skill in the technical field to which the present invention belongs from the following description. I will be able to.

According to an embodiment, a temperature control device for controlling a temperature of a liquid lens includes: a thermistor having a resistance value that varies according to the temperature of the liquid lens; A storage unit for storing a relationship between the resistance value of the thermistor and the temperature of the liquid lens; A temperature sensing unit that senses the resistance value of the thermistor and outputs the sensed resistance value in digital form; From the relationship stored in the storage unit, a temperature of the liquid lens corresponding to the resistance value in the digital form is obtained, the obtained temperature of the liquid lens is compared with a target temperature of the liquid lens, and the compared result is used as a control signal. A control unit that outputs; And a lens heating unit that heats the liquid lens in response to the control signal.

For example, the thermistor may be disposed on the liquid lens and may have the resistance value proportional to the temperature of the liquid lens.

For example, the relationship between the temperature of the liquid lens stored in the storage unit and the resistance value of the thermistor may be obtained in advance.

For example, the temperature sensing unit may include a measurement voltage applying unit that applies a digital measurement voltage to the thermistor; And a temperature determining unit configured to determine the measured voltage, which is varied according to the resistance value of the thermistor, as the sensed resistance value.

For example, the control unit may include a synthesis unit for synthesizing the target temperature of the liquid lens and the obtained temperature of the liquid lens to generate a difference value between the target temperature and the obtained temperature of the liquid lens; And a control signal generator that generates the control signal according to the difference value.

For example, the lens heating unit may include a current source for applying a current having a level that increases or decreases in response to the control signal; And a heating resistor disposed on the liquid lens and generating heat in response to the current.

For example, the level of the current applied from the current source may decrease as the digital code value, which is the control signal, increases.

For example, the current source may include a digital variable resistor disposed between a first supply voltage and a reference voltage and having a resistance value varying in response to the digital code value; A transistor disposed between a second supply voltage and the heating resistor to apply the current to the heating resistor; A first resistor disposed between the second supply voltage and the transistor; And a comparison unit comparing a voltage drop of the digital variable resistor with a voltage at a contact point between the first resistor and the transistor, and the transistor may operate in response to a result compared by the comparison unit.

For example, the comparator may include a comparator, and the comparator may include a first input terminal connected to the contact point; A second input terminal connected to the voltage drop of the digital variable resistor; And an output terminal connected to the transistor.

For example, the current source may include a second resistor disposed between the digital variable resistor and the reference potential; And a Zener diode connected in parallel with the digital variable resistor.

According to another embodiment, a method for controlling a temperature of a liquid lens includes: sensing a resistance value that varies according to the temperature of the liquid lens; Obtaining a temperature of the liquid lens corresponding to the sensed resistance value; Checking whether the obtained temperature of the liquid lens reaches a target temperature of the liquid lens; Heating the liquid lens if the obtained temperature of the liquid lens has not reached the target temperature; And stopping the heating of the liquid lens when the obtained temperature of the liquid lens reaches the target temperature.

The apparatus and method for controlling a temperature of a liquid lens according to an embodiment can minimize a decrease in resolution of a liquid lens due to a diopter change caused by a temperature change. In particular, the temperature control apparatus and method of a liquid lens according to the embodiment can minimize the diopter change according to the temperature change of the liquid lens by simply controlling the temperature of the liquid lens without considering many factors with a simple configuration. It is possible to minimize the decrease in resolution of the liquid lens due to the diopter change caused, and has an effect that there is no need to calibrate the temperature of the liquid lens.

In addition, the effects obtained in the present embodiment are not limited to the above-mentioned effects, and another effect not mentioned can be clearly understood by those of ordinary skill in the field to which the present invention belongs from the following description. There will be.

1 is a block diagram of an apparatus for controlling a temperature of a liquid lens according to an embodiment.

2 is a flowchart illustrating a method of controlling a temperature of a liquid lens according to an exemplary embodiment.

3 is a view for explaining the liquid lens shown in FIG. 1.

4A is a block diagram of a temperature sensing unit 130A according to an embodiment shown in FIG. 1, and FIG. 4B is a block diagram of another embodiment of the temperature sensing unit illustrated in FIG. 1.

5 is a block diagram of a control unit shown in FIG. 1 according to an embodiment.

6 is a graph for explaining an example of a current applied from a current source to a heating resistor.

7 shows a circuit diagram according to an embodiment of the current source shown in FIG. 1.

8 is a graph for explaining a correlation between a diopter and a temperature of a liquid lens.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical idea of the present invention is not limited to some embodiments to be described, but may be implemented in various forms, and within the scope of the technical idea of the present invention, one or more of the constituent elements may be selectively selected. It can be combined with and substituted for use.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention are generally understood by those of ordinary skill in the art, unless explicitly defined and described. It can be interpreted as a meaning, and terms generally used, such as terms defined in a dictionary, may be interpreted in consideration of the meaning in the context of the related technology.

In addition, terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention. In the present specification, the singular form may include the plural form unless specifically stated in the phrase, and when described as “at least one (or more than one) of A and/or B and C”, it is combined with A, B, and C. It may contain one or more of all possible combinations.

In addition, terms such as first, second, A, B, (a), and (b) may be used in describing the constituent elements of the embodiment of the present invention. These terms are only for distinguishing the component from other components, and are not limited to the nature, order, or order of the component by the term.

And, if a component is described as being'connected','coupled' or'connected' to another component, the component is not only directly connected, coupled or connected to the other component, but also the component and The case of being'connected','coupled', or'connected' due to another element between the other elements may also be included.

In addition, when it is described as being formed or disposed on the “top (top) or bottom (bottom)” of each component, the top (top) or bottom (bottom) is one as well as when the two components are in direct contact with each other. It also includes a case in which the above other component is formed or disposed between the two components. In addition, when expressed as "upper (upper) or lower (lower)", the meaning of not only an upward direction but also a downward direction based on one component may be included.

The variable lens may be a variable focus lens. Also, the variable lens may be a lens whose focus is adjusted. The variable lens may be at least one of a liquid lens, a polymer lens, a liquid crystal lens, a VCM type, and an SMA type. The liquid lens may include a liquid lens including one liquid and a liquid lens including two liquids. A liquid lens containing one liquid may change the focus by adjusting a membrane disposed at a position corresponding to the liquid, and for example, the focus may be changed by pressing the membrane by electromagnetic force of a magnet and a coil. A liquid lens including two liquids may control an interface formed between the conductive liquid and the non-conductive liquid by using a voltage applied to the liquid lens including a conductive liquid and a non-conductive liquid. The polymer lens can change the focus of the polymer material through a driving unit such as piezo. The liquid crystal lens can change the focus by controlling the liquid crystal by electromagnetic force. The VCM type can change the focus by adjusting the solid lens or the lens assembly including the solid lens through the electromagnetic force between the magnet and the coil. The SMA type can change focus by controlling a solid lens or a lens assembly including a solid lens using a shape memory alloy.

Hereinafter, the temperature control apparatus and method according to the embodiment controls the temperature of the liquid lens as a variable lens, but is not limited thereto. That is, even when the temperature control apparatus and method according to the embodiment controls the temperature of a variable lens other than a liquid lens, the following description may be applied.

Hereinafter, an apparatus and method for controlling a temperature of a liquid lens according to an exemplary embodiment will be described with reference to the accompanying drawings.

1 is a block diagram of an apparatus 100 for controlling a temperature of a liquid lens according to an embodiment, and FIG. 2 is a flowchart illustrating a method 200 for controlling a temperature of a liquid lens according to an embodiment.

The temperature control method 200 of the liquid lens shown in FIG. 2 may be performed in the temperature control apparatus 100 of the liquid lens shown in FIG. 1, and the temperature control apparatus 100 of the liquid lens shown in FIG. Although the temperature control method 200 of the liquid lens illustrated in FIG. 2 may be performed, the embodiment is not limited thereto. That is, according to another embodiment, the temperature control method 200 of a liquid lens shown in FIG. 2 is performed in a temperature control device of a liquid lens having a configuration different from that of the temperature control device 100 of the liquid lens shown in FIG. Alternatively, the temperature control apparatus 100 for a liquid lens illustrated in FIG. 1 may perform a temperature control method for a liquid lens different from the temperature control method 200 for a liquid lens illustrated in FIG. 2.

Before describing the temperature control apparatus 100 and method 200 of a liquid lens illustrated in FIGS. 1 and 2, a general configuration of the liquid lens 10 will be described as follows with reference to the accompanying drawings.

3 is a diagram for explaining the liquid lens 10 shown in FIG. 1.

Referring to FIG. 3, the liquid lens 10 includes a plurality of different types of liquids LQ1 and LQ2, first to third plates P1, P2 and P3, and first and second electrodes E1 and E2. And an insulating layer 16.

The plurality of liquids LQ1 and LQ2 are accommodated in the cavity CA, and may include a first liquid LQ1 having conductivity and a second liquid (or insulating liquid) LQ2 having a non-conductive property. . The first liquid LQ1 and the second liquid LQ2 are not mixed with each other, and an interface BO may be formed in a contact portion between the first and second liquids LQ1 and LQ2. For example, the second liquid LQ2 may be disposed on the first liquid LQ1, but the embodiment is not limited thereto.

The first liquid LQ1 may be implemented with a material having a conductivity, and the second liquid LQ2 may be implemented with a material having a non-conductive property such as oil.

The inner surface of the first plate P1 may form a sidewall i of the cavity CA. The first plate P1 may include upper and lower openings having a predetermined inclined surface. That is, the cavity CA may be defined as a region surrounded by an inclined surface of the first plate P1, a first opening in contact with the second plate P2, and a second opening in contact with the third plate P3.

Among the first and second openings, the diameter of the wider opening may vary depending on the FOV required by the liquid lens 10 or the role that the liquid lens 10 plays in the camera module. The interface BO formed by the two liquids may move along the slope of the cavity CA by the driving voltage.

The opening area in the direction in which light is incident from the cavity CA may be narrower than the opening area in the opposite direction. Alternatively, the liquid lens 10 may be implemented so that the inclination direction of the cavity CA is opposite. In addition, when the liquid lens 10 is disposed so that the inclination direction of the cavity CA is opposite, the entire or part of the arrangement of the components included in the liquid lens 10 is changed according to the inclination direction of the liquid lens 10. Alternatively, only the inclination direction of the cavity CA may be changed, and the arrangement of the remaining components may not be changed.

The first liquid LQ1 and the second liquid LQ2 may be filled, accommodated, or disposed in the cavity CA of the first plate P1. In addition, the cavity CA is a portion through which light that has passed through the first lens unit (not shown) is transmitted. Therefore, the first plate P1 may be made of a transparent material, or may contain impurities so that light transmission is not easy.

First and second electrodes E1 and E2 may be disposed on one surface and the other surface of the first plate P1, respectively. The plurality of first electrodes E1 may be spaced apart from the second electrode E2 and may be disposed on one surface (eg, an upper surface, a side surface, and a lower surface) of the first plate P1. The second electrode E2 is disposed on at least a portion of the other surface (eg, the lower surface) of the first plate P1 and may directly contact the first liquid LQ1.

As described above, the plurality of first electrodes E1 may correspond to individual electrodes that may be electrically separated from each other, and the plurality of second electrodes E2 may correspond to common electrodes that may not be electrically separated from each other. have. Each of the first and second electrodes E1 and E2 may be made of a conductive material.

Also, the second plate P2 may be disposed on one surface of the first electrode E1. That is, the second plate P2 may be disposed on the first plate P1. Specifically, the second plate P2 may be disposed on the upper surface of the first electrode E1 and the cavity CA.

The third plate P3 may be disposed on one surface of the second electrode E2. That is, the third plate P3 may be disposed under the first plate P1. Specifically, the third plate P3 may be disposed under the lower surface of the second electrode E2 and the cavity CA.

The second plate P2 and the third plate P3 may be disposed to face each other with the first plate P1 interposed therebetween. Also, at least one of the second plate P2 and the third plate P3 may be omitted.

Each of the second and third plates P2 and P3 is a region through which light passes, and may be made of a light-transmitting material. For example, each of the second and third plates P2 and P3 may be made of glass, and may be made of the same material for convenience of the process.

The second plate P2 may have a configuration that allows light incident from the first lens unit to proceed into the cavity CA of the first plate P1. The third plate P3 may have a configuration that allows light that has passed through the cavity CA of the first plate P1 to proceed to the second lens unit (not shown). The third plate P3 may directly contact the first liquid LQ1.

The liquid lens 10 shown in FIG. 3 may further include a bonding member 15. The bonding member (or adhesive) 15 is disposed between the first plate P1 and the third plate P3 and serves to couple the first plate P1 and the third plate P3 to each other.

Alternatively, the liquid lens 10 illustrated in FIG. 3 may further include a plate leg (LEG) 15 instead of including the bonding member 15. The plate leg 15 is disposed between the first plate P1 and the third plate P3 and serves to support the third plate P3. Here, the plate leg 15 may be integrally implemented with the same material as the third plate P3.

The insulating layer 16 may be disposed in the upper region of the cavity CA while covering a part of the lower surface of the second plate P2. That is, the insulating layer 16 may be disposed between the second liquid LQ2 and the second plate P2. In addition, the insulating layer 16 may be disposed while covering a part of the first electrode E1 forming a sidewall of the cavity CA. In addition, the insulating layer 16 may be disposed on the lower surface of the first plate P1 to cover a part of the second electrode E2 and the first plate P1 and the first electrode E1. Accordingly, contact between the first electrode E1 and the first liquid LQ1 and contact between the first electrode E1 and the second liquid LQ2 may be blocked by the insulating layer 16.

The insulating layer 16 covers one of the first and second electrodes E1 and E2 (for example, the first electrode E1), and the other electrode (for example, the second electrode E2). )) may be exposed to apply electric energy to the conductive first liquid LQ1.

The first connection substrate 12 and the second connection substrate 14 serve to supply voltage to the liquid lens 10. To this end, the plurality of first electrodes E1 may be electrically connected to the first connection substrate 12, and the second electrode E2 may be electrically connected to the second connection substrate 14.

When the driving voltage is applied to the first and second electrodes E1 and E2 through the first connection substrate 12 and the second connection substrate 14, between the first liquid LQ1 and the second liquid LQ2 The interface BO of is deformed so that at least one of a shape such as a curvature or a focal length of the liquid lens 10 may be changed (or adjusted). For example, the focal length of the liquid lens 10 may be adjusted while at least one of the curvature or inclination of the interface BO formed in the liquid lens 10 is changed in response to the driving voltage. When the deformation, radius of curvature, and tilting angle of the interface BO are controlled, the liquid lens 10, the lens assembly including the liquid lens 10, the camera module, and the optical device are auto-focusing (AF). A function, camera shake correction, or an OIS (Optical Image Stabilizer) function can be performed.

The first connection substrate 12 may transmit four different individual voltages to the liquid lens 10, and the second connection substrate 14 may transmit one common voltage to the liquid lens 10. The common voltage may include a DC voltage or an AC voltage. When the common voltage is applied in the form of a pulse, the width or duty cycle of the pulse may be constant. Individual voltages supplied through the first connection substrate 12 may be applied to the plurality of first electrodes E1 exposed to each corner of the liquid lens 10.

The apparatus 100 and the method 200 for temperature control of a liquid lens according to the embodiment shown in FIGS. 1 and 2 may control the temperature of the liquid lens 10 shown in FIG. 3, and are shown in FIG. 3. It is also possible to control the temperature of the liquid lens 10 having a cross section different from that of the one. That is, the temperature control apparatus 100 and method 200 of a liquid lens according to the embodiment are not limited to a specific cross section of the liquid lens 10 to be controlled.

Referring again to FIGS. 1 and 2, an apparatus 100 and a method 200 for controlling a temperature of a liquid lens according to an embodiment will be described as follows.

The temperature control apparatus 100 for a liquid lens may include a thermistor 110, a storage unit 120, a temperature sensing unit 130, a control unit 140, and a lens heating unit 150.

The thermistor 110 may have a resistance value that varies depending on the temperature of the liquid lens 10.

The thermistor 110 may be disposed inside the liquid lens 10 as shown in FIG. 1, but the embodiment is not limited thereto. According to another embodiment, the thermistor 110 may be disposed around the liquid lens 10, for example, on the first or

second connection substrates

12 and 14. The embodiment is not limited to a specific position where the thermistor 110 is disposed.

In addition, the resistance value of the thermistor 110 may be proportional or inversely proportional to the temperature of the liquid lens 10. In this way, since the resistance value of the thermistor 110 represents the temperature of the liquid lens 10, the temperature of the liquid lens 10 can be inferred through the resistance value of the thermistor 110.

To this end, the storage unit 120 may store a relationship between the resistance value of the thermistor 110 and the temperature of the liquid lens 10.

According to the embodiment, the relationship between the temperature of the liquid lens 10 stored in the storage unit 120 and the resistance value of the thermistor 110 may be obtained in advance. For example, the temperature of the liquid lens 10 may be mapped for each resistance value of the thermistor 110 and stored in the storage unit 120 in the form of a Look Up Table (LUT).

In addition, the relationship between the temperature of the liquid lens 10 and the resistance value of the thermistor 110 may be experimentally obtained in advance in the temperature chamber and stored in the storage unit 120.

In addition, the storage unit 120 may store a relational expression for obtaining the temperature of the liquid lens 10 from the resistance value.

For example, the storage unit 120 may be implemented as a flash memory, but the embodiment is not limited to a specific memory type of the storage unit 120.

According to the temperature control method 200 of the liquid lens according to the embodiment, first, a resistance value that varies according to the temperature of the liquid lens 10 is sensed (step 210). To this end, the temperature sensing unit 130 may sense a resistance value of the thermistor 110 and output the sensed resistance value to the controller 140 in a digital form.

4A is a block diagram of an embodiment 130A of the temperature sensing unit 130 illustrated in FIG. 1.

According to an embodiment, the temperature sensing unit 130A may include a measurement voltage application unit 132 and a temperature determination unit 134.

The measurement voltage application unit 132 may apply a digital measurement voltage (eg, “0000”) to the thermistor 110 through the output terminal OUT1. In this case, the digital measurement voltage may be varied according to the resistance value of the thermistor 110. For example, the digital measurement voltage may be applied to the thermistor 110 in a form of pulse width modulation (PWM).

The temperature determination unit 134 may determine a measured voltage that varies according to the resistance value of the thermistor 110 as a sensed resistance value, and may output the determined digital resistance value to the controller 140 through the output terminal OUT2. .

4B is a block diagram of another embodiment 130B of the temperature sensing unit 130 illustrated in FIG. 1.

According to another embodiment, the temperature sensing unit 130B may include a sensor 136 and an analog-to-digital converter (ADC) 138.

The sensor 138 is connected to the thermistor 110 through the input terminal IN1, senses a resistance value of the thermistor 110, and outputs the sensed resistance value to the ADC 138.

The ADC 138 may convert a resistance value sensed by the sensor 136 into a digital form and output the converted digital resistance value to the controller 140 through an output terminal OUT3.

On the other hand, the control unit 140 receives the resistance value in digital form from the temperature sensing unit 130, and from the relationship between the resistance value stored in the storage unit 120 and the temperature, the liquid lens 10 Find the temperature (step 220).

After step 220, the controller 140 may compare the obtained temperature of the liquid lens 10 with a target temperature of the liquid lens 10, and output the result of the comparison to the lens heating unit 150 as a control signal ( Step 230). That is, the control unit 140 may determine whether the obtained temperature of the liquid lens 10 reaches the target temperature of the liquid lens 10.

FIG. 5 is a block diagram illustrating an embodiment 140A of the controller 140 shown in FIG. 1.

According to an embodiment, the control unit 140A may include a synthesis unit 142 and a control signal generation unit 144.

The synthesis unit 142 synthesizes the target temperature of the liquid lens 10 and the obtained temperature of the liquid lens 10, and uses the synthesized result as a difference value between the target temperature and the obtained temperature of the liquid lens 10 as a control signal generation unit. It can be printed as (144). To this end, the synthesis unit 142 may receive the target temperature of the liquid lens 10 through the input terminal IN2, and receive the obtained temperature of the liquid lens 10 through the input terminal IN3. For example, the target temperature of the liquid lens 10 may be provided from the outside of the temperature control apparatus 100 of the liquid lens shown in FIG. 1 or may be stored in the storage unit 120.

The control signal generation unit 144 may generate a control signal according to the difference value provided from the synthesis unit 142 and output the generated control signal to the lens heating unit 150 through the output terminal OUT4.

Meanwhile, the lens heating unit 150 heats the liquid lens 10 in response to a control signal output from the control unit 140.

That is, if the obtained temperature of the liquid lens 10 has not reached the target temperature, the control unit 140 controls the lens heating unit 150 to heat the liquid lens 10 through a control signal (step 240).

However, if the obtained temperature of the liquid lens 10 reaches the target temperature, the control unit 140 may stop the operation of the lens heating unit 150 to heat the liquid lens 10 through a control signal (No. 250 step). Alternatively, if the obtained temperature of the liquid lens 10 reaches the target temperature, the controller 140 may reduce the degree to which the lens heating unit 150 heats the liquid lens 10 through a control signal (step 250 ).

According to an embodiment, as illustrated in FIG. 1, the lens heating unit 150 may include a current source 152 and at least one heating resistor 154.

The current source 152 may apply a current having a level that increases or decreases in response to a control signal output from the controller 140 to the at least one heating resistor 154.

For example, if the obtained temperature of the liquid lens 10 has not reached the target temperature, in response to the control signal output from the controller 140, the current source 152 converts the current having the increased level to the heating resistor 154. The liquid lens 10 can be heated by applying.

In addition, when the obtained temperature of the liquid lens 10 reaches the target temperature, in response to a control signal output from the controller 140, the current source 152 applies a current having a reduced level to the heating resistor 154 The degree of heating the lens 10 can be reduced. Alternatively, if the obtained temperature of the liquid lens 10 reaches the target temperature, the current source 152 may not apply current to the heating resistor 154 in response to a control signal output from the controller 140.

6 is a graph for explaining an example of the current output from the current source 152 to the heating resistor 154, where the horizontal axis represents a code value and the vertical axis represents the current.

For example, the level of the current applied from the current source 152 to the heating resistor 154 may decrease as the digital code value (code), which is a control signal, increases. As an example, as illustrated in FIG. 6, the level of the current applied from the current source 152 is constantly maintained at a maximum value in the first section R1 of the digital code value code. In the second section R2 of ), it may decrease as the code value increases. That is, the second section R2 is a section in which the level of the current applied from the current source 152 to the heating resistor 154 is varied.

For example, in order to finely vary the level of the current in the second section R2, the digital code value code may be subdivided into various values ranging from 0 to 255.

7 shows a circuit diagram of the current source 152 shown in FIG. 1 according to an embodiment 152A.

According to an embodiment, the current source 152A may include a digital variable resistor 310, a transistor TR, a first resistor R1 and a comparator 320.

The digital variable resistor 310 is disposed between the first supply voltage VD1 and a reference voltage (for example, a ground voltage), in response to a digital code value, which is a control signal received from the controller 140 through an input terminal IN4. It can have a variable resistance value. As shown in FIG. 6, the resistance value of the digital variable resistor 310 may be varied so that the level of the current supplied from the current source 152A to the heating resistor 154 decreases as the code value increases. .

The transistor TR is disposed between the second supply voltage VD2 and the heating resistor 154 and serves to apply a current to the heating resistor 154. For example, the transistor TR may be in the form of a MOSFET (Metal-Oxide-Semiconductor Field-Effect-Transistor) as shown in FIG. 7, or may be in a bipolar form as shown in FIG. 7, The embodiment is not limited to a specific shape of the transistor TR.

If the transistor TR is a PMOS transistor as shown in FIG. 7, the transistor TR has a source connected to the second supply voltage VD2, a drain connected to the heating resistor 154, and the comparison unit 320. It may include a gate connected to the output.

Also, the first supply voltage VD1 and the second supply voltage VD2 may have different levels or may have the same level.

The first resistor R1 may be disposed between the second supply voltage VD2 and the transistor TR.

The comparison unit 320 compares the voltage at the contact point CP between the first resistor R1 and the transistor TR and the voltage drop of the digital variable resistor 310, and outputs the compared result to the transistor TR. can do. In this case, the transistor TR may operate in response to a result compared by the comparison unit 320.

For example, the comparator 320 may include a comparator 322. The comparator 322 may include a first input terminal IT1, a second input terminal IT2, and an output terminal OT. The first input terminal IT1 is connected to the contact point CP, the second input terminal IT2 is connected to the voltage drop of the digital variable resistor 310, and the output terminal OT is a transistor TR (for example, a gate ) Can be connected.

The operation of the current source 152A shown in FIG. 7 will be briefly described as follows.

The transistor TR may be turned on or turned off by the voltage Vgs between the source and the gate of the transistor TR. For example, when each of the first and second supply voltages VD1 and VD2 is 5 volts and the width of the variable resistance of the digital variable resistor 310 is 50 kΩ, the voltage Vgs is 1 volt, the transistor TR Can be turned on. When the transistor TR is turned on, the current supplied to the heating resistor 154 increases, and when the transistor TR is turned off, the current supplied to the heating resistor 154 decreases or the current is supplied to the heating resistor 154 May not be.

Further, the current source 152A may further include a second resistor R2 disposed between the digital variable resistor 310 and the reference potential. The second resistor R2 serves to distribute the first supply voltage VD1 to the digital variable resistor 310. That is, the maximum value of the voltage drop of the digital variable resistor 310 may be determined according to the value of the second resistor R2.

In addition, the current source 152A may further include a Zener diode ZD connected in parallel with the digital variable resistor 310. As the Zener diode ZD is disposed as described above, the current supplied to the heating resistor 154 may be stabilized.

Referring back to FIG. 1, at least one heating resistor 154 may be disposed inside the liquid lens 10 as illustrated in FIG. 1, and unlike FIG. 1, the periphery of the liquid lens 10 May be placed in. The embodiment is not limited to a specific position where the heating resistor 154 is disposed.

The at least one heating resistor 154 generates heat in response to a current supplied from the current source 152 and heats the liquid lens 10, thereby increasing the temperature of the liquid lens 10. For example, the at least one heating resistor 154 may include two

heating resistors

154A and 154B as shown in FIG. 1, but the embodiment is not limited to a specific number of the heating resistors 154 . That is, according to another embodiment, unlike FIG. 1, the number of heating resistors 154 may be one or three or more.

8 is a graph for explaining a correlation between a diopter and a temperature of the liquid lens 10.

Referring to FIG. 8, when the temperature of the liquid lens 10 is saturated, the temperature 910 sensed by the thermistor 110, the temperature 912 above the liquid lens 10, and the liquid lens 10 There may be very little or no deviation between the temperature 914 in the outside air. It takes a lot of time until the temperature 910 sensed by the thermistor 110 and the

temperatures

912 and 914 of the liquid lens 10 become thermally parallel.

At this time, referring to FIG. 8, it can be seen that when the

temperatures

910, 912, and 914 of the liquid lens 10 change, the diopter of the liquid lens 10 changes. In this way, when the diopter changes due to the sensitive reaction of the liquid lens 10 to temperature, the performance of the liquid lens 10 may deteriorate. For example, when the diopter changes according to the temperature change of the liquid lens 10, the liquid lens 10 cannot properly perform the AF function or the OIS function. Consideration factors for controlling such diopter change are increased, and an optical module including the liquid lens 10 may have a complex configuration.

However, the temperature control apparatus 100 and method 200 of a liquid lens according to the embodiment includes the thermistor 110, the heating resistor 154, the storage unit 120, the temperature sensing unit 130, and the control unit 140. By simply controlling the temperature of the liquid lens 10 without having to consider many factors with a simple configuration including, it is possible to minimize the diopter change according to the temperature change of the liquid lens 10. Accordingly, the apparatus 100 and method 200 for controlling a temperature of a liquid lens according to an exemplary embodiment can minimize a decrease in resolution of a liquid lens due to a diopter change caused by a temperature change.

In general, when the temperature of the liquid lens is sub-zero, it is necessary to calibrate the temperature of the liquid lens. However, the apparatus 100 and the method 200 for controlling the temperature of a liquid lens according to an exemplary embodiment, when the temperature of the liquid lens 10 is a sub-zero temperature that does not reach the target temperature, heats the heating resistor 154 to generate a liquid. Since the temperature of the lens 10 can be increased to the temperature of the image, there is no need to calibrate the temperature of the liquid lens.

Meanwhile, an optical device may be implemented using a camera module including the liquid lens control apparatus 100 according to the above-described embodiment. Here, the optical device may include a device capable of processing or analyzing an optical signal. Examples of optical devices may include a camera/video device, a telescope device, a microscope device, an interferometer device, a photometer device, a polarimeter device, a spectrometer device, a reflectometer device, an autocollimator device, a lens meter device, and the like, including a lens assembly. This embodiment can be applied to an optical device capable of.

In addition, the optical device may be implemented as a portable device such as a smart phone, a notebook computer, or a tablet computer. Such an optical device may include a camera module, a display unit (not shown) that outputs an image, a battery (not shown) that supplies power to the camera module, and a camera module, a display unit, and a body housing on which the battery is mounted. The optical device may further include a communication module capable of communicating with other devices and a memory unit capable of storing data. The communication module and the memory unit may also be mounted on the main body housing.

The embodiments have been described above, but these are only examples and do not limit the present invention, and those of ordinary skill in the field to which the present invention belongs are not illustrated above within the scope not departing from the essential characteristics of the present embodiment. It will be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be modified and implemented. And differences related to these modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

The mode for carrying out the invention has been sufficiently described in the above-described "Best mode for carrying out the invention."

The temperature control device and method of a liquid lens according to the embodiment is a camera/video device, a telescope device, a microscope device, an interferometer device, a photometer device, a polarimeter device, a spectrometer device, a reflectometer device, an autocollimator device, a lens meter device, and a smartphone. , Laptop computers, tablet computers, and the like.

Claims

A thermistor having a resistance value that varies according to the temperature of the liquid lens;

A storage unit for storing a relationship between the resistance value of the thermistor and the temperature of the liquid lens;

A temperature sensing unit that senses the resistance value of the thermistor and outputs the sensed resistance value in digital form;

From the relationship stored in the storage unit, a temperature of the liquid lens corresponding to the resistance value in the digital form is obtained, the obtained temperature of the liquid lens is compared with a target temperature of the liquid lens, and the compared result is used as a control signal. A control unit that outputs; And

In response to the control signal, a temperature control device for a liquid lens including a lens heating unit for heating the liquid lens.
The apparatus of claim 1, wherein the thermistor is disposed on the liquid lens and has the resistance value proportional to the temperature of the liquid lens.
The apparatus of claim 1, wherein the relationship between the temperature of the liquid lens stored in the storage unit and the resistance value of the thermistor is obtained in advance.
The method of claim 1, wherein the temperature sensing unit

A measurement voltage application unit for applying a digital measurement voltage to the thermistor; And

A temperature control device for a liquid lens including a temperature determination unit configured to determine the measured voltage, which is varied according to the resistance value of the thermistor, as the sensed resistance value.
The method of claim 1, wherein the control unit

A synthesis unit for synthesizing the target temperature of the liquid lens and the obtained temperature of the liquid lens to generate a difference value between the target temperature and the obtained temperature of the liquid lens; And

Temperature control apparatus of a liquid lens including a control signal generator for generating the control signal according to the difference value.
The method of claim 1, wherein the lens heating unit

A current source for applying a current having a level that increases or decreases in response to the control signal; And

A temperature control device of a liquid lens disposed on the liquid lens and including a heating resistor that generates heat in response to the current.
7. The apparatus of claim 6, wherein the level of the current applied from the current source decreases as the digital code value of the control signal increases.
The method of claim 7, wherein the current source is

A digital variable resistor disposed between the first supply voltage and the reference voltage and having a resistance value that varies in response to the digital code value;

A transistor disposed between a second supply voltage and the heating resistor to apply the current to the heating resistor;

A first resistor disposed between the second supply voltage and the transistor; And

A comparison unit for comparing a voltage drop of the digital variable resistor with a voltage at a contact point between the first resistor and the transistor,

The transistor is a temperature control device for a liquid lens operating in response to the result compared by the comparison unit.
The method of claim 8, wherein the comparator comprises a comparator, and the comparator

A first input terminal connected to the contact point;

A second input terminal connected to the voltage drop of the digital variable resistor; And

Including an output terminal connected to the transistor,

The current source is

A second resistor disposed between the digital variable resistor and the reference potential; And

Temperature control device of a liquid lens further comprising a Zener diode connected in parallel with the digital variable resistor.
Sensing a resistance value that varies according to the temperature of the liquid lens;

Obtaining a temperature of the liquid lens corresponding to the sensed resistance value;

Checking whether the obtained temperature of the liquid lens reaches a target temperature of the liquid lens;

Heating the liquid lens if the obtained temperature of the liquid lens has not reached the target temperature; And

And stopping heating of the liquid lens when the obtained temperature of the liquid lens reaches the target temperature.