KR20220133548A - Camera actuator and camera module comprising the same - Google Patents

Abstract

A camera actuator according to an embodiment of the present invention includes: a printed circuit board; a drive coil disposed on one surface of the printed circuit board; a drive magnet spaced apart from the drive coil; a heater disposed on the other side of the printed circuit board facing the one side of the printed circuit board and facing the drive coil; and a thermal pad part extended from one surface of the printed circuit board to the other surface of the printed circuit board and thermally connecting the driving coil and the heater.

Description

A camera actuator and a camera module including the same

The present invention relates to a camera actuator and a camera module including the same.

A camera is a device that takes a picture or video of a subject, and is mounted on a portable device, a drone, a vehicle, or the like. The camera module has an image stabilization (IS) function that corrects or prevents image shake caused by user movement to improve image quality, and automatically adjusts the distance between the image sensor and the lens to align the focal length of the lens. It may have a zooming function of increasing or decreasing the magnification of a distant subject through an auto-focusing (AF) function and a zoom lens.

On the other hand, the resolution of the image sensor increases as the pixel becomes higher and the size of the pixel becomes smaller. As the pixel becomes smaller, the amount of light received for the same time decreases. Therefore, the higher the pixel camera, the more severe the image shake caused by hand shake that occurs when the shutter speed is slowed in a dark environment. As a representative image stabilization (IS) technology, there is an optical image stabilizer (OIS) technology that corrects motion by changing the path of light.

Looking at an example of OIS technology, a camera movement is detected through a gyrosensor, etc., and a lens is tilted or moved based on the detected movement, or a camera module including a lens and an image sensor can be tilted or moved. . To this end, an actuator for the OIS may be placed around the lens. In this case, the actuator for OIS may include two axes perpendicular to the optical axis Z, that is, an actuator in charge of tilting the X-axis and an actuator in charge of tilting the Y-axis. Such a camera actuator may use a coil and a magnet.

However, in the case of the coil, there is a problem in that stable control is difficult because the resistance characteristics change according to the generated heat.

An embodiment is to provide a camera actuator capable of improving control accuracy and a camera module including the same.

The problem to be solved in the embodiment is not limited thereto, and it will be said that the purpose or effect that can be grasped from the solving means or embodiment of the problem described below is also included.

A camera actuator according to an embodiment of the present invention includes a printed circuit board; a driving coil disposed on one surface of the printed circuit board; a driving magnet spaced apart from the driving coil; a heater disposed on the other surface of the printed circuit board opposite to one surface of the printed circuit board and disposed opposite to the driving coil; and a thermal pad part extending from one surface of the printed circuit board to the other surface of the printed circuit board and thermally connecting the driving coil and the heater.

It may further include; a heat conduction unit disposed between the other surface of the printed circuit board and the heater.

The heat conduction unit may include a non-magnetic material having thermal conductivity greater than or equal to a predetermined value.

Thermal grease may be disposed between the thermal pad part and the thermal conductive part.

The thermal pad unit may include: a first thermal pad disposed on one surface of the printed circuit board and connected to the driving coil; a second thermal pad disposed on the other surface of the printed circuit board and connected to the heater; and a connection member connecting the first thermal pad and the second thermal pad.

The connection member may include an insulator having thermal conductivity greater than or equal to a predetermined value.

and a temperature sensor disposed on one surface of the printed circuit board.

The heater may radiate heat to maintain a preset target temperature based on the temperature information sensed by the temperature sensor.

The target temperature may be set based on a temperature of the coil generated when a preset maximum current is applied.

The heater may be a thermoelectric element.

When the heater is a thermoelectric element, the target temperature may be set to a temperature lower than a temperature of the coil generated when a preset maximum current is applied.

A camera module according to an embodiment of the present invention is a camera module including a camera actuator for performing at least one of a focusing (AF) function and an image stabilization (OIS) function, wherein the camera actuator includes: a printed circuit board; a driving coil disposed on one surface of the printed circuit board; a driving magnet spaced apart from the driving coil; a heater disposed on the other surface of the printed circuit board opposite to one surface of the printed circuit board and disposed opposite to the driving coil; and a thermal pad part extending from one surface of the printed circuit board to the other surface of the printed circuit board and thermally connecting the driving coil and the heater.

According to an embodiment, it is possible to provide stable control of the camera actuator.

When the camera actuator is driven, the time required for stabilizing the coil resistance characteristic can be shortened.

Various and advantageous advantages and effects of the present invention are not limited to the above, and will be more easily understood in the course of describing specific embodiments of the present invention.

1 is a perspective view of a camera module according to an embodiment of the present invention.
2 is an exploded perspective view of a camera module according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view taken along line AA′ in FIG. 1 .
4 is a perspective view of a first camera actuator according to an embodiment.
5 is an exploded perspective view of a first camera actuator according to an embodiment.
6 is a diagram illustrating a first driving unit of a first camera actuator according to an exemplary embodiment.
7 is a view showing the structure of a camera actuator according to an embodiment of the present invention.
8 is a view for explaining a change in resistance of a driving coil according to an embodiment of the present invention.
9 is a perspective view of a mobile terminal to which a camera module according to an embodiment is applied.

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

However, the technical spirit of the present invention is not limited to some embodiments described, but may be implemented in various different forms, and within the scope of the technical spirit of the present invention, one or more of the components may be selected between the embodiments. It can be combined and substituted for use.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be generally understood by those of ordinary skill in the art to which the present invention pertains, unless specifically defined and described explicitly. It may be interpreted as a meaning, and generally used terms such as terms defined in advance may be interpreted in consideration of the contextual meaning of the related art.

In addition, the terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention.

In this specification, the singular form may also include the plural form unless otherwise specified in the phrase, and when it is described as "at least one (or one or more) of A and (and) B, C", it is combined with A, B, C It may include one or more of all possible combinations.

In addition, in describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used.

These terms are only for distinguishing the component from other components, and are not limited to the essence, order, or order of the component by the term.

And, when it is described that a component is 'connected', 'coupled' or 'connected' to another component, the component is not only directly connected, coupled or connected to the other component, but also with the component It may also include the case of 'connected', 'coupled' or 'connected' due to another element between the other elements.

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

1 is a perspective view of a camera module according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of a camera module according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along line AA′ in FIG. 1 .

1 and 2 , the camera module 1000 according to the embodiment may include a cover CV, a first camera actuator 1100 , a second camera actuator 1200 , and a circuit board 1300 . . Here, the first camera actuator 1100 may be used as a first actuator, and the second camera actuator 1200 may be used as a second actuator.

The cover CV may cover the first camera actuator 1100 and the second camera actuator 1200 . The coupling force between the first camera actuator 1100 and the second camera actuator 1200 may be improved by the cover CV.

Furthermore, the cover CV may be made of a material that blocks electromagnetic waves. Accordingly, the first camera actuator 1100 and the second camera actuator 1200 in the cover CV can be easily protected.

In addition, the first camera actuator 1100 may be an optical image stabilizer (OIS) actuator. For example, the first camera actuator 1100 may move the optical member in a direction perpendicular to the optical axis.

The first camera actuator 1100 may include fixed focal length les disposed on a predetermined barrel (not shown). Fixed focal length les may also be referred to as “single focal length lenses” or “single focal length lenses”.

The first camera actuator 1100 may change the path of the light. In an embodiment, the first camera actuator 1100 may vertically change the optical path through an optical member (eg, a prism or a mirror) therein. With this configuration, even if the thickness of the mobile terminal is reduced, a lens configuration larger than the thickness of the mobile terminal is disposed in the mobile terminal through a change in the optical path, so that magnification, auto-focusing (AF) and OIS functions can be performed.

However, the present invention is not limited thereto, and the first camera actuator 1100 may change the optical path vertically or at a predetermined angle a plurality of times.

The second camera actuator 1200 may be disposed behind the first camera actuator 1100 . The second camera actuator 1200 may be coupled to the first camera actuator 1100 . And the mutual coupling may be made by various methods.

Also, the second camera actuator 1200 may be a zoom actuator or an auto focus (AF) actuator. For example, the second camera actuator 1200 may support one or a plurality of lenses and may perform an auto-focusing function or a zoom function by moving the lenses according to a control signal of a predetermined controller.

In addition, one or a plurality of lenses may independently or individually move along the optical axis direction to perform an auto-focusing function or a medium function.

The circuit board 1300 may be disposed at a rear end of the second camera actuator 1200 . The circuit board 1300 may be electrically connected to the second camera actuator 1200 and the first camera actuator 1100 . Also, there may be a plurality of circuit boards 1300 . The circuit board 1300 may include an image sensor and the like, and may include a connector electrically connected to another external camera module or process of a terminal.

Referring to FIG. 3 , the camera module according to the embodiment may include a first camera actuator 1100 performing an OIS function and a second camera actuator 1200 performing a zooming function and an AF function.

Light may be incident into the camera module or the first camera actuator through an opening area located on the upper surface of the first camera actuator 1100 . That is, the light may be incident into the interior of the first camera actuator 1100 in a vertical direction (eg, the X-axis direction), and the optical path may be changed in the optical-axis direction (eg, the Z-axis direction) through the optical member. Here, vertical direction is used interchangeably with “vertically” and “along vertically”. In addition, the light may pass through the second camera actuator 1200 and be incident on the image sensor IS located at one end of the second camera actuator 1200 .

4 is a perspective view of a first camera actuator according to the embodiment, and FIG. 5 is an exploded perspective view of the first camera actuator according to the embodiment.

4 and 5 , the first camera actuator 1100 according to the embodiment includes a first housing 1120 , a mover 1130 , a rotating unit 1140 , a first driving unit 1150 , and a fastening member 1131a. ) is included.

First, the first camera actuator 1100 may include a shield can (not shown). The shield can (not shown) may be positioned at the outermost side of the first camera actuator 1100 to surround the rotating part 1140 and the first driving part 1150 to be described later.

Such a shield can (not shown) may block or reduce electromagnetic waves generated from the outside. That is, the shield can (not shown) may reduce the occurrence of a malfunction in the rotating unit 1140 or the first driving unit 1150 .

The first housing 1120 may be located inside a shield can (not shown). When there is no shield can, the first housing 1120 may be located at the outermost side of the first camera actuator.

In addition, the first housing 1120 may be located inside the first substrate unit 1154 to be described later. The first housing 1120 may be fastened by fitting or matching with a shield can (not shown).

The first housing 1120 may include a first housing side 1121 , a second housing side 1122 , a third housing side 1123 , a fourth housing side 1124 , and a fifth housing side 1126 . have.

The mover 1130 includes a holder 1131 and an optical member 1132 seated on the holder 1131 .

The holder 1131 may be seated in the receiving part 1125 of the first housing 1120 . The holder 1131 includes a first holder outer surface corresponding to the first housing side 1121 , the second housing side 1122 , the third housing side 1123 , and the fifth housing side 1126 , respectively, in addition to the fourth holder. side may be included. For example, the first holder outer surface to the fourth holder outer surface may have inner surfaces of the first housing side 1121 , the second housing side 1122 , the third housing side 1123 , and the fifth housing side 1126 , respectively. may correspond or face.

The optical member 1132 may be seated on the holder 1131 . To this end, the holder 1131 may have a seating surface, a bottom surface, or a surface in the receiving groove, and the seating surface may be formed by the receiving groove. In an embodiment, the optical member 1132 may be formed of a mirror or a prism. Hereinafter, a prism is shown as a reference, but may be formed of a plurality of lenses. Alternatively, the optical member 1132 may include a plurality of lenses and prisms or mirrors. In addition, the optical member 1132 may include a reflector disposed therein. However, the present invention is not limited thereto.

Also, the optical member 1132 may reflect light reflected from the outside (eg, an object) into the camera module. In other words, the optical member 1132 may improve the spatial limit of the first camera actuator and the second camera actuator by changing the path of the reflected light. As such, it should be understood that the camera module may extend the optical path while minimizing thickness to provide a high range of magnification.

The rotating part 1140 may include a tilting guide part 1141 and a first magnetic body 1142 and a second magnetic body 1143 having different polarities to press the tilting guide part 1141 .

The tilting guide unit 1141 may be coupled to the above-described mover 1130 and the first housing 1120 . Specifically, the tilting guide part 1141 may be disposed between the holder 1131 and the fifth housing side part 1126 . Accordingly, the tilting guide unit 1141 may be coupled to the mover 1130 and the first housing 1120 of the holder 1131 . However, unlike the above description, in the present embodiment, the tilting guide part 1141 may be disposed between the fifth housing side part 1126 and the holder 1131 . Specifically, the tilting guide part 1141 may be positioned between the fifth housing side part 1126 and the fourth outer seating groove of the holder 1131 .

In the third direction (Z-axis direction), the fastening member 1131a, the fifth housing side part 1126, the tilting guide part 1141, and the holder 1131 may be disposed in the order (based on the outermost side). In addition, the first magnetic body 1142 and the second magnetic body 1143 are seated in the first fastening groove gr1 formed in the fastening member 1131a and the second fastening groove gr2 formed in the fifth housing side 1126, respectively. can do. In this embodiment, the positions of the first fastening grooves gr1 and the second fastening grooves gr2 may be different from those of the first and second grooves described in the other embodiments described above. However, the first fastening groove gr1 is located in the fastening member 1131a and moves integrally with the holder, and the second fastening groove gr2 corresponds to the first fastening groove gr1 and the fifth housing side 1126. It is positioned on the first housing 1120 and is coupled thereto. Accordingly, the present terms will be used interchangeably. In addition, a second fastening groove gr2 may be positioned between the first fastening groove gr1 and the tilting guide part 1141 .

Also, the tilting guide unit 1141 may be disposed adjacent to the optical axis. Accordingly, the actuator according to the embodiment can easily change the optical path according to the first and second axis tilt to be described later.

The first driving unit 1150 includes a first driving magnet 1151 , a first driving coil 1152 , a Hall sensor unit 1153 , a first substrate unit 1154 , and a yoke unit 1155 .

The first magnetic material 1142 and the second magnetic material 1143 may have the same polarity. For example, the first magnetic body 1142 may be a magnet having an N pole, and the second magnetic body 1143 may be a magnet having an N pole. Alternatively, the first magnetic body 1142 may be a magnet having an S pole, and the second magnetic body 1143 may be a magnet having an S pole.

For example, the second pole surface of the second magnetic material 1143 and the first pole surface of the first magnetic material 1142 facing the second pole surface may have the same polarity. That is, the first magnetic body 1142 and the second magnetic body 1143 may generate a force to repel each other, and for this, various materials and functions may be provided.

For example, the first magnetic body 1142 and the second magnetic body 1143 may generate a repulsive force between each other due to the above-described polarity. With this configuration, the above-described repulsive force is coupled to the fastening member 1131a or holder 1131 and the second magnetic body 1143 coupled to the first magnetic body 1142 and the fifth housing side 1126 or the first housing ( 1120) can be added. At this time, the repulsive force applied to the fastening member 1131a may be transmitted to the holder 1131 coupled to the fastening member 1131a. Accordingly, the tilting guide portion 1141 disposed between the fastening member 1131a and the fifth housing side portion 1126 may be closely pressed by the repulsive force. That is, the repulsive force may maintain the tilting guide part 1141 positioned between the holder 1131 and the first housing 1120 (or the fifth housing side part 1126 ). With this configuration, the position between the mover 1130 and the first housing 1120 may be maintained even during the X-axis tilt or the Y-axis tilt. In addition, the tilting guide part may be in close contact with the fifth housing side part 1126 and the holder 1131 by a repulsive force between the second magnetic body 1143 and the first magnetic body 1142 .

6 is a diagram illustrating a first driving unit of a first camera actuator according to an embodiment.

Referring to FIG. 6 , the first driving unit 1150 includes a first driving magnet 1151 , a first driving coil 1152 , a Hall sensor unit 1153 , a first substrate unit 1154 , and a yoke unit 1155 . include Also, the first driving magnet 1151 may include a first magnet 1151a , a second magnet 1151b , and a third magnet 1151c providing driving force by electromagnetic force. The first magnet 1151a , the second magnet 1151b , and the third magnet 1151c may be positioned adjacent to the outer surface of the holder 1131 , respectively. For example, the first magnet 1151a , the second magnet 1151b , and the third magnet 1151c may be respectively located in grooves on the outer surface of the holder 1131 .

Also, the first driving coil 1152 may include a plurality of coils. In an embodiment, the first driving coil 1152 may include at least one coil, and the at least one coil may be positioned to correspond to at least one magnet of the above-described first driving magnet. For example, the first driving coil 1152 may include a first coil 1152a , a second coil 1152b , and a third coil 1152c .

The first coil 1152a may be positioned to face the first magnet 1151a. Accordingly, the first coil 1152a may be positioned in the first housing hole 1121a of the first housing side 1121 as described above. Also, the second coil 1152b may be positioned to face the second magnet 1151b. Accordingly, the second coil 1152b may be positioned in the second housing hole 1122a of the second housing side 1122 as described above.

The second camera actuator according to the embodiment moves the mover 1130 along the first axis (X-axis direction) or the second axis (Y-axis direction) by electromagnetic force between the first driving magnet 1151 and the first driving coil 1152 . It is possible to provide the best optical characteristics by minimizing the occurrence of a decent or tilt phenomenon when implementing OIS by controlling the rotation.

In addition, according to the embodiment, through the tilting guide part 1141 of the rotating part 1140 disposed between the first housing 1120 and the mover 1130, OIS is implemented to solve the size limitation of the actuator, so that the ultra-slim, ultra-small camera It is possible to provide an actuator and a camera module including the same.

The first substrate portion 1154 may include a first substrate side portion 1154a , a second substrate side portion 1154b , and a third substrate side portion 1154c .

The first substrate side portion 1154a and the second substrate side portion 1154b may be disposed to face each other. In addition, the third substrate side portion 1154c may be positioned between the first substrate side portion 1154a and the second substrate side portion 1154b.

Also, the first substrate side 1154a may be positioned between the first housing side and the shield can, and the second substrate side 1154b may be positioned between the second housing side and the shield can. Also, the third substrate side part 1154c may be positioned between the third housing side part and the shield can, and may be the bottom surface of the first substrate part 1154 .

The first substrate side portion 1154a may be coupled to the first coil 1152a and electrically connected thereto. In addition, the first substrate side portion 1154a may be coupled to and electrically connected to the first Hall sensor 1153a.

The second substrate side 1154b may be coupled to and electrically connected to the second coil 1152b. Also, it should be understood that the second substrate side 1154b may engage and electrically connect with the first Hall sensor.

The third substrate side 1154c may be coupled to and electrically connected to the third coil 1152c. In addition, the third substrate side portion 1154c may be coupled to and electrically connected to the second Hall sensor 1153b.

The yoke unit 1155 may include a first yoke 1155a, a second yoke 1155b, and a third yoke 1155c. The first yoke 1155a may be located in the first outer seating groove and may be coupled to the first magnet 1151a. In addition, the second yoke 1155b may be positioned in the second outer seating groove and coupled to the second magnet 1151b. In addition, the third yoke 1155c may be located in the third outer seating groove and may be coupled to the third magnet 1151c. The first to third yokes 1155a to 1155c allow the first to third magnets 1151a to 1151c to be easily seated in the first to third outer seating grooves to be coupled to the housing.

Although the first camera actuator of the camera module described above is described in FIGS. 4 and 5 , the second camera actuator of the camera module according to an embodiment of the present invention may also include a second driving unit. The second driving unit may also include a second driving magnet, a second driving coil, a Hall sensor unit, and a second substrate unit.

7 is a view showing the structure of a camera actuator according to an embodiment of the present invention.

The camera actuator described in FIG. 7 may be applied to the camera module according to the embodiment of the present invention. The camera actuator structure of FIG. 6 may be a structure applicable to both the first camera actuator and the second camera actuator described above.

7, the camera actuator according to the embodiment of the present invention is a printed circuit board 2100, a driving coil 2200, a driving magnet 2300, a heater 2400, a heat conduction unit 2600, a thermal pad unit ( 2500 ), a temperature sensor 2700 , and a controller 2800 .

First, the printed circuit board 2100 may correspond to the above-described board unit. The printed circuit board 2100 may include one surface and the other surface. The other surface of the printed circuit board 2100 may mean a surface opposite to one surface of the printed circuit board 2100 . One surface of the printed circuit board 2100 may mean a surface facing the driving magnet 2300 .

The printed circuit board 2100 may include a plurality of sides. The side portions adjacent to each other may extend by forming a predetermined angle. For example, the printed circuit board 2100 may include three sides (a first side, a second side, and a third side), and adjacent ones of the three sides may form an angle of approximately 90 degrees. . The second side may extend from the first side and the third side may extend from the second side. The first side and the second side may form an angle of approximately 90 degrees, the second side and the third side may form an angle of approximately 90 degrees, and the first side and the second side may be spaced apart and parallel to each other. .

A driving coil 2200 may be disposed on one surface of the printed circuit board 2100 . A circuit capable of supplying power to the driving coil 2200 may be disposed on the printed circuit board 2100 . According to an exemplary embodiment, a driving coil 2200 may be disposed on one surface of each of the plurality of side portions included in the printed circuit board 2100 . For example, when three side portions are included, the driving coil 2200 may be disposed on one surface of each of the three side portions of the printed circuit board 2100 . A Hall sensor may be disposed on one surface of the printed circuit board 2100 . According to an embodiment, the Hall sensor may be disposed adjacent to the driving coil 2200 .

A temperature sensor 2700 may be disposed on one surface of the printed circuit board 2100 . The printed circuit board 2100 may include a circuit for supplying power for driving the temperature sensor 2700 and transmitting the sensed temperature information. According to an exemplary embodiment, a temperature sensor 2700 may be disposed on one surface of each of the plurality of side portions included in the printed circuit board 2100 . For example, when including three sides, the temperature sensor 2700 may be disposed on one surface of each of the three sides of the printed circuit board 2100 .

A heater 2400 may be disposed on the other surface of the printed circuit board 2100 . The printed circuit board 2100 may include a circuit for supplying power for driving the heater 2400 and transmitting and receiving a control signal. According to an embodiment, a heater 2400 may be disposed on the other surface of each of the plurality of side portions included in the printed circuit board 2100 . For example, when three side portions are included, the heater 2400 may be disposed on the other surface of each of the three side portions of the printed circuit board 2100 .

Next, the driving coil 2200 may correspond to the above-described driving coil. The driving coil 2200 may be disposed on one surface of the printed circuit board 2100 . The driving coil 2200 may be electrically connected to a circuit included in the printed circuit board 2100 . The driving coil 2200 may receive power through a circuit included in the printed circuit board 2100 . As a current flows in the driving coil 2200 by the supplied power, a Lorentz force may be generated between the corresponding driving magnets 2300 .

The driving coil 2200 may generate heat when power is supplied (ie, current is applied). The driving coil 2200 may generate more heat as the amount of applied current increases. Since the driving coil 2200 may have a resistance characteristic (eg, a size of a resistance) changed according to heat generated, the resistance characteristic may be changed according to a change in the amount of current. Accordingly, even when currents of the same magnitude are applied, differences in control may occur. In particular, when the applied current is not constant, the amount of generated heat is also not constant, so the variation of the resistance characteristic is also not constant, so that it may be more difficult to control the camera actuator. In order to solve this problem, the present invention is provided with a heater 2400, which will be described later.

Next, the driving magnet 2300 may be disposed to face the driving coil 2200 . The driving magnet 2300 may be spaced apart from the driving coil 2200 . The driving magnet 2300 may be disposed to be coupled to a member such as a lens holder or a prism holder to face the driving coil 2200 . The driving magnet 2300 may be disposed to correspond to each of the driving coils 2200 . For example, when there are three driving coils 2200 , there may be three driving magnets 2300 , and the three driving magnets 2300 may be disposed to face each of the corresponding driving coils 2200 .

Next, the heater 2400 may be disposed on the other surface of the printed circuit board 2100 . The heater 2400 may be disposed on the other surface of the printed circuit board 2100 to face the driving coil 2200 . Accordingly, when there are a plurality of driving coils 2200 , there may also be a plurality of heaters 2400 .

The heater 2400 may supply heat to the driving coil 2200 or absorb heat of the driving coil 2200 to maintain the temperature of the correspondingly disposed driving coil 2200 at a preset target temperature. According to an embodiment of the present invention, the temperature of the driving coil 2200 can quickly reach the target temperature through heat or endothermic heat of the heater 2400, thereby reducing the driving delay of the camera actuator. In addition, the temperature can be kept constant, and accordingly, the resistance characteristic of the coil can also be kept constant, so that the control accuracy of the camera actuator can be improved.

According to an embodiment, the heater 2400 may be an element that supplies heat to the driving coil 2200 . For example, the heater 2400 may be implemented as a ceramic heater. The ceramic heater may refer to a heater having a structure in which a heating wire, which is a heating part, is wound around a ceramic to generate heat. For example, in the case of a camera module installed in a smartphone, the size is very small. Accordingly, the size of the heater that can be attached to the camera actuator of the camera module is also very limited. One embodiment of the present invention can solve this problem by using a ceramic heater having a small size, high thermal efficiency and a short heating time, which has high energy efficiency. In this case, the target temperature may be set as the temperature of the driving coil 2200 generated when a preset maximum current is applied to the driving coil 2200 . For example, when the driving of the camera actuator starts, the temperature of the driving coil 2200 rises and reaches a predetermined temperature (eg, the temperature of the driving coil 2200 when the maximum current is applied). At this time, the driving coil Since the resistance characteristic of the driving coil 2200 is changed until the temperature of the 2200 reaches a predetermined temperature, precise control becomes difficult. In order to increase the accuracy of the control, the control of the driving unit should be performed after the temperature of the driving coil 2200 reaches a predetermined temperature, but it may take a lot of time until the temperature of the driving coil 2200 reaches the predetermined temperature. have. In order to solve this problem, in the present invention, heat is supplied to the driving coil 2200 through the heater 2400 so that the temperature of the driving coil 2200 quickly reaches the target temperature, thereby improving the reaction speed. In addition, since the temperature of the driving coil 2200 supplies heat to maintain the target temperature, a change in resistance characteristics that may occur according to a change in the amount of current applied after the temperature of the driving coil 2200 reaches the target temperature can prevent According to an embodiment, the target temperature may be set within a range of 40 degrees to 60 degrees in consideration of the driving coil 2200 of the camera actuator and supply power.

In another embodiment, the heater 2400 may be implemented as a thermoelectric element. The thermoelectric element may refer to a device using a Peltier effect, in which one side absorbs heat and the opposite side heats up according to the direction of the current when a DC voltage is applied. When implemented as a thermoelectric element, the heater 2400 may maintain the temperature of the driving coil 2200 at a predetermined temperature by transferring heat to the coil through heat generation or absorbing heat from the coil through heat absorption. When a thermoelectric element is used, unlike the structure in which the heater 2400 performs only heat generation, heat absorption and heat generation can be performed according to control, so that the target temperature is the temperature of the driving coil 2200 generated when a preset maximum current is applied. It can be set to a lower temperature. For example, the target temperature may be set to a room temperature of about 25 degrees, and the heater 2400 may repeat heat generation and endothermic heat so that the temperature of the driving coil 2200 maintains the target temperature. Since the target temperature can be set to room temperature, the heater 2400 has the advantage of maintaining the temperature of the driving coil 2200 at the target temperature with low power consumption.

Next, the heat conduction unit 2600 may be disposed between the other surface of the printed circuit board 2100 and one surface of the heater 2400 . One surface of the heater 2400 may mean a surface facing the printed circuit board 2100 , and the other surface of the heater 2400 may mean a surface facing the one surface of the heater 2400 . The heat conduction unit 2600 may be disposed between the other surface of the printed circuit board 2100 and one surface of the heater 2400 facing it. As an embodiment, the heat conduction unit 2600 may be configured to surround the heater 2400 . The heat conduction unit 2600 may be configured to surround the entire heater 2400 or surround one surface of the heater 2400 and a side surface extending therefrom. As another example, the heat conduction unit 2600 may be configured in a plate shape. In this case, the plate may be configured to have an area equal to or greater than that of one surface of the heater 2400 in contact.

The heat conduction unit 2600 may be a non-magnetic material having a higher thermal conductivity than a predetermined value. For example, the heat conduction unit 2600 may be made of aluminum (Al), a non-magnetic material having a thermal conductivity of 200C [W/m.K] or more.

According to an embodiment, the heater 2400 may generate a magnetic field when heat is radiated or absorbed according to the structure of the heater 2400 . The magnetic field generated by the heater 2400 may affect the driving coil 2200 disposed oppositely and the hall sensors disposed adjacent to each other, thereby making it difficult to precisely control the driving unit. In order to solve this problem, the present invention implements the heat conduction unit 2600 with a non-magnetic material that has high thermal conductivity and can not be affected by a magnetic field at the same time, so that the magnetic field generated by the heater 2400 is transferred to the printed circuit. The influence on the driving coil 2200 or the Hall sensor disposed on one surface of the substrate 2100 is minimized.

Next, the thermal pad unit 2500 may be disposed to extend from one surface to the other surface of the printed circuit board 2100 , and may be connected to the driving coil 2200 and the heat conduction unit 2600 . The thermal pad unit 2500 may include a first thermal pad 2510 , a second thermal pad 2520 , and a connection member 2530 .

The first thermal pad 2510 may be disposed on one surface of the printed circuit board 2100 . The first thermal pad 2510 may be connected to the driving coil 2200 . The first thermal pad 2510 may be connected to the temperature sensor 2700 . The temperature sensor 2700 may measure the temperature of the driving coil 2200 by sensing heat transferred through the first thermal pad 2510 .

The second thermal pad 2520 may be disposed on the other surface of the printed circuit board 2100 . The second thermal pad 2520 may be connected to the thermal conduction unit 2600 . As another example, when the camera actuator does not include a heat conduction unit, the second thermal pad 2520 may be directly connected to the heater 2400 . According to an embodiment, thermal grease may be disposed between the thermal pad part 2500 and the thermal conductive part 2600 . Thermal grease may be disposed between one surface of the second thermal pad 2520 and one surface of the heat conduction unit 2600 . In this case, the thermal grease may be a non-conductive material. Since the thermal grease is disposed between the second thermal pad 2520 and the thermal conductive part 2600 , heat transfer efficiency between the thermal conductive part 2600 and the thermal pad part 2500 may be improved.

The connection member 2530 may connect the first thermal pad 2510 and the second thermal pad 2520 . According to an embodiment, the connection member 2530 may pass through the printed circuit board 2100 to connect the first thermal pad 2510 and the second thermal pad 2520 . Through this, a heat transfer path between the first thermal pad 2510 and the second thermal pad 2520 may be minimized, and thus heat loss may be minimized.

The connection member 2530 may include an insulator having thermal conductivity greater than or equal to a predetermined value. For example, the connecting member 2530 may be formed of mica, which is an insulator having a thermal conductivity of 200C [W/m.K] or more. As the connecting member 2530 is formed of an insulator having a thermal conductivity greater than or equal to a predetermined value, heat transfer efficiency between the first thermal pad 2510 and the second thermal pad 2520 can be improved as well as the heater 2400 . ), it is possible to improve the control accuracy of the drive unit by blocking the electrical noise generated by it.

Next, the temperature sensor 2700 may be disposed on one surface of the printed circuit board 2100 . The temperature sensor 2700 may be disposed on one surface of the printed circuit board 2100 on which the driving coil 2200 is disposed. The temperature sensor 2700 may be disposed on the heat conduction unit 2600 . The temperature sensor 2700 may be disposed on the first thermal pad 2510 . The temperature sensor 2700 may be disposed adjacent to the driving coil 2200 . The temperature sensor 2700 , the driving coil 2200 , and the heater 2400 may be disposed adjacent to each other so as to minimize a smoke loss. Through this, the temperature of the driving coil 2200 may be accurately measured by minimizing heat loss.

The temperature of the driving coil 2200 measured by the temperature sensor 2700 may be used to control the heater 2400 . The driving coil 2200 measured by the temperature sensor 2700 may be transmitted to the control unit, and the control unit may control the operation of the heater 2400 through a comparison result between the measured temperature and the set target temperature.

Next, the control unit 2800 may be disposed on one surface of the printed circuit board 2100 . The controller 2800 may be disposed adjacent to the temperature sensor 2700 . The controller 2800 may be a drive IC. The controller 2800 may be plural, and may be disposed for each of the plurality of heaters 2400 .

The controller 2800 may receive temperature information measured from the temperature sensor 2700 . The controller 2800 may turn-on or turn-off the heater 2400 using a result of comparing the received temperature information with the target temperature. The controller 2800 may maintain the temperature of the driving coil 2200 as a target temperature through turn-on and turn-off control of the heater 2400 . For example, when the measured temperature information is lower than the target temperature, the controller 2800 may control the turn-on of the heater 2400 by outputting the GPIO to High. Conversely, when the measured temperature information is higher than the target temperature, the controller 2800 may turn off the heater 2400 by outputting the GPIO to Low. According to an embodiment, after reaching the target temperature, when the measured temperature information is lower than the target temperature by a predetermined value (eg, 10 degrees), the controller 2800 turns on the heater 2400 to restart the operation. can do. Then, when the measured temperature information reaches the target temperature, the heater 2400 may be controlled to turn off.

8 is a view for explaining a change in resistance of a driving coil according to an embodiment of the present invention.

Referring to FIG. 8 , when a current starts to flow in the driving coil, heat is generated due to its own resistance. As described above, when heat is generated in the driving coil and the temperature rises, the resistance value of the driving coil gradually decreases, thereby increasing the amount of current flowing through the driving coil, and parasitic inductance by the coil. to increase This affects the Hall sensor disposed adjacent to the driving coil (eg, an increase in the Hall sensor value according to a change in the magnetic field).

When the temperature of the driving coil reaches a specific temperature, it is stabilized (saturation), and accordingly, the Hall sensor value is also stabilized. After the Hall sensor value is stabilized, hall calibration of the camera actuator may be performed. Thereafter, the camera actuator may be driven after stabilizing by increasing the temperature of the driving coil to make the camera actuator into a hall calibration state during initial driving.

However, as shown in FIG. 8 , it takes a considerable amount of time for the driving coil to reach a stable state without a heater according to the embodiment of the present invention. In the example of FIG. 8 , it may take about 3 minutes or more for the driving coil to reach a stable state without a heater.

However, as shown in FIG. 8 , when the driving coil is heated using the heater according to the embodiment of the present invention, the time for the driving coil to reach the stabilization state may be greatly reduced. In the example of FIG. 8 , when the driving coil is heated through a heater, it may take about 1 minute to reach a stable state.

As such, the camera actuator of the present invention has the advantage of greatly reducing the delay time for preparation during calibration and initial driving.

9 is a perspective view of a mobile terminal to which a camera module according to an embodiment is applied.

As shown in FIG. 9 , the mobile terminal 1500 of the embodiment may include a camera module 1000 , a flash module 1530 , and an auto-focusing device 1510 provided on the rear side.

The camera module 1000 may include an image capturing function and an auto focus function. For example, the camera module 1000 may include an auto-focus function using an image.

The camera module 1000 processes an image frame of a still image or a moving image obtained by an image sensor in a shooting mode or a video call mode.

The processed image frame may be displayed on a predetermined display unit and stored in a memory. A camera (not shown) may also be disposed on the front of the mobile terminal body.

For example, the camera module 1000 may include a first camera module 1000A and a second camera module 1000B, and OIS may be implemented together with an AF or zoom function by the first camera module 1000A. can In addition, AF, zoom, and OIS functions may be performed by the second camera module 1000b. In this case, since the first camera module 1000A includes both the above-described first camera actuator and the second camera actuator, it is possible to easily reduce the size of the camera device or the camera module by changing the optical path.

The flash module 1530 may include a light emitting device that emits light therein. The flash module 1530 may be operated by a camera operation of a mobile terminal or a user's control.

The autofocus device 1510 may include one of the packages of the surface light emitting laser device as a light emitting part.

The auto-focusing device 1510 may include an auto-focusing function using a laser. The auto focus device 1510 may be mainly used in a condition in which the auto focus function using the image of the camera module 1000 is deteriorated, for example, close to 10 m or less or in a dark environment.

The autofocus device 1510 may include a light emitting unit including a vertical cavity surface emitting laser (VCSEL) semiconductor device and a light receiving unit that converts light energy such as a photodiode into electrical energy.

In the above, the embodiment has been mainly described, but this is only an example and does not limit the present invention, and those of ordinary skill in the art to which the present invention pertains are not exemplified above in the range that does not depart from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be implemented by modification. And the 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.

2100: printed circuit board
2200: drive coil
2300: driving magnet
2400 : heater
2500: thermal pad unit
2600: heat conduction unit
2700 : temperature sensor
2800: control unit

Claims (12)

printed circuit board;
a driving coil disposed on one surface of the printed circuit board;
a driving magnet spaced apart from the driving coil;
a heater disposed on the other surface of the printed circuit board opposite to one surface of the printed circuit board and disposed opposite to the driving coil; and
and a thermal pad part extending from one surface of the printed circuit board to the other surface of the printed circuit board and thermally connecting the driving coil and the heater. According to claim 1,
The camera actuator further comprising a; heat conduction unit disposed between the other surface of the printed circuit board and the heater. 3. The method of claim 2,
The heat conduction unit,
A camera actuator comprising a non-magnetic material having thermal conductivity greater than or equal to a predetermined value. 3. The method of claim 2,
A camera actuator in which thermal grease is disposed between the thermal pad part and the heat conduction part. According to claim 1,
The thermal pad part,
a first thermal pad disposed on one surface of the printed circuit board and connected to the driving coil;
a second thermal pad disposed on the other surface of the printed circuit board and connected to the heater; and
and a connection member connecting the first thermal pad and the second thermal pad. 6. The method of claim 5,
The connecting member is
A camera actuator comprising an insulator having a thermal conductivity greater than or equal to a predetermined value. According to claim 1,
A camera actuator comprising a; temperature sensor disposed on one surface of the printed circuit board. 8. The method of claim 7,
The heater is
A camera actuator that radiates heat to maintain a preset target temperature based on the temperature information sensed by the temperature sensor. 9. The method of claim 8,
The target temperature is
A camera actuator set based on the temperature of the coil generated when a preset maximum current is applied. 9. The method of claim 8,
The heater is
A camera actuator that is a thermoelectric element. 11. The method of claim 10,
The target temperature is
When the heater is a thermoelectric element, the camera actuator is set to a temperature lower than the temperature of the coil generated when a preset maximum current is applied. A camera module comprising a camera actuator for performing at least one of a focusing (AF) function and an image stabilization (OIS) function,
The camera actuator is
printed circuit board;
a driving coil disposed on one surface of the printed circuit board;
a driving magnet spaced apart from the driving coil;
a heater disposed on the other surface of the printed circuit board opposite to one surface of the printed circuit board and disposed opposite to the driving coil; and
and a thermal pad part extending from one surface of the printed circuit board to the other surface of the printed circuit board and thermally connecting the driving coil and the heater.

Images