KR102427383B1 - Camera module - Google Patents

Abstract

A camera module according to an embodiment of the present invention includes a lens module having a plurality of lenses; a housing accommodating the lens module; a driving unit including a magnet provided in the lens module and a coil disposed to face the magnet; a yoke generating attractive force with respect to the magnet; and a first ball member and a second ball member disposed between the lens module and the housing and pressed by the attractive force, wherein the housing includes a first protrusion protruding toward the first ball member and the second ball member A second protrusion protruding toward the second ball member may be provided, and the first protrusion and the second protrusion may have different lengths in an optical axis direction.

Description

camera module

The present invention relates to a camera module.

Recently, a camera module has been employed in mobile communication terminals such as smart phones, tablet PCs, and notebook computers. Such a camera module is provided with a focus adjustment function to generate a high-resolution image.

When the focus is adjusted, the lens module is moved in the optical axis direction by the actuator. In this case, a plurality of ball bearings may be used to support the movement of the lens module in the optical axis direction. The plurality of ball bearings come into contact with the lens module and support the lens module by rolling motion in the optical axis direction.

Preferably, all of the plurality of ball bearings should be able to support the lens module by contacting the lens module, but it is very difficult to make the sizes of the plurality of ball bearings exactly the same in the manufacturing process, so the size of the plurality of ball bearings is actually may vary.

When there is a slight difference in the sizes of the plurality of ball bearings, only some of the ball bearings come into contact with the lens module, and accordingly, there is a possibility that a tilt may occur when the lens module is moved in the optical axis direction.

Furthermore, while the lens module is moved in the optical axis direction, a ball bearing in contact with the lens module may be changed, and thus, a tilt phenomenon in which the lens module is tilted may continuously occur.

In addition, since it is difficult to visually check the size difference between the plurality of ball bearings, it is difficult to predict which ball bearing among the plurality of balls will come into contact with the lens module.

Since it is very important for the lens module to move in parallel in the optical axis direction in focus adjustment, it is necessary to prevent a tilt from occurring when the lens module is moved.

On the other hand, the size of a camera module used in a recent mobile communication terminal is gradually reduced in size, and as the size of the camera module decreases, the problem of a decrease in resolution due to the tilt of the lens module increases.

An object of the present invention is to provide a camera module capable of preventing a tilt (Tilt) from occurring when the lens module is moved in the optical axis direction.

A camera module according to an embodiment of the present invention includes a lens module having a plurality of lenses; a housing accommodating the lens module; a driving unit including a magnet provided in the lens module and a coil disposed to face the magnet; a yoke generating attractive force with respect to the magnet; and a first ball member and a second ball member disposed between the lens module and the housing and pressed by the attractive force, wherein the housing includes a first protrusion protruding toward the first ball member and the second ball member A second protrusion protruding toward the second ball member may be provided, and the first protrusion and the second protrusion may have different lengths in an optical axis direction.

A camera module according to an embodiment of the present invention includes a housing having a first accommodating groove and a second accommodating groove; a lens module accommodated in the housing and having a third accommodating groove facing the first accommodating groove and a fourth accommodating groove facing the second accommodating groove; a first ball member disposed between the first accommodating groove and the third accommodating groove and including a plurality of balls disposed along an optical axis direction; and a second ball member disposed between the second accommodating groove and the fourth accommodating groove, the second ball member including a plurality of balls disposed along the optical axis direction; The number and the number of the plurality of balls of the second ball member are different, and the length in the optical axis direction of the surface where the first accommodating groove and the third accommodating groove face each other is the second accommodating groove and the fourth The length of the surfaces of the receiving grooves facing each other in the optical axis direction may be different.

The camera module according to an embodiment of the present invention may prevent a tilt from occurring when the lens module is moved in the optical axis direction.

1 is a perspective view of a camera module according to an embodiment of the present invention.
2 is a schematic exploded perspective view of a camera module according to an embodiment of the present invention.
3 is a view for explaining a case in which a tilt occurs while the lens module is moved.
4 is a cross-sectional view taken along line II′ of FIG. 1 .
FIG. 5 is a view showing a modified example of FIG. 4 .
FIG. 6 is a view showing another modified example of FIG. 4 .
7 is a perspective view of a housing according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. However, the spirit of the present invention is not limited to the presented embodiment.

For example, those skilled in the art who understand the spirit of the present invention will be able to propose other embodiments included within the scope of the present invention through addition, change, or deletion of components, but this is also the spirit of the present invention. will be considered to be within the scope.

In addition, terms including an ordinal number such as "first", "second", etc. used herein may be used to describe various elements, but the elements are not limited by the terms, and the terms are It is used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

The present invention relates to a camera module, and may be applied to portable electronic devices such as mobile communication terminals, smart phones, and tablet PCs.

1 is a perspective view of a camera module according to an embodiment of the present invention, Figure 2 is a schematic exploded perspective view of the camera module according to an embodiment of the present invention.

1 and 2 , the camera module according to an embodiment of the present invention includes a lens module 200 , a driving unit 300 for moving the lens module 200 , and light incident through the lens module 200 . It includes a housing 400 and a case 100 accommodating the image sensor module 500 and the lens module 200 that are converted into electrical signals.

The lens module 200 may include a lens barrel 210 and a carrier 230 .

At least one lens for imaging a subject may be accommodated in the lens barrel 210 . When a plurality of lenses are disposed, the plurality of lenses are mounted in the lens barrel 210 along the optical axis. The lens barrel 210 may have a hollow cylindrical shape.

The lens barrel 210 is coupled to the carrier 230 , and the lens barrel 210 and the carrier 230 are accommodated in the housing 400 and the case 100 . The case 100 is coupled to the housing 400 so as to surround the outer surface of the housing 400 .

The lens barrel 210 is configured to be movable in the optical axis direction together with the carrier 230 .

That is, the lens module 200 can be moved in the optical axis direction to adjust the focus, and the driving unit 300 is provided to move the lens module 200 .

An image sensor module 500 is disposed under the housing 400 . The image sensor module 500 is a device that converts light incident through the lens module 200 into an electrical signal.

The image sensor module 500 may include an image sensor 510 and a printed circuit board 530 connected to the image sensor 510 , and may further include an infrared filter.

The infrared filter serves to block light in the infrared region among the light incident through the lens module 200 .

The image sensor 510 converts light incident through the lens barrel 210 into an electrical signal. For example, the image sensor 510 may be a charge coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS).

The electrical signal converted by the image sensor 510 is output as an image through the display unit of the portable electronic device.

The image sensor 510 is fixed to the printed circuit board 530 and is electrically connected to the printed circuit board 530 by wire bonding.

The driving unit 300 includes a magnet 310 and a coil 320 . The magnet 310 may be provided in the lens module 200 , and the coil 320 may be disposed to face the magnet 310 .

For example, the magnet 310 may be mounted on one surface of the carrier 230 , and the coil 320 may be provided on one surface of the substrate 330 mounted on the housing 400 . The magnet 310 and the coil 320 may be disposed to face each other in a direction perpendicular to the optical axis direction.

When power is applied to the coil 320 , the carrier 230 may be moved in the optical axis direction by the electromagnetic influence between the magnet 310 and the coil 320 .

Since the lens barrel 210 is mounted on the carrier 230 , the lens barrel 210 is also moved in the optical axis direction by the movement of the carrier 230 .

When the lens module 200 is moved in the optical axis direction, the first ball member 600 and the second ball member 600 and the second between the lens module 200 and the housing 400 to reduce friction between the lens module 200 and the housing 400 . Two ball members 700 are disposed.

A first accommodating space is provided between the lens module 200 and the housing 400 , and the first ball member 600 is accommodated in the first accommodating space. In addition, a second accommodating space is formed between the lens module 200 and the housing 400 , and the second ball member 700 is accommodated in the second accommodating space.

A first accommodating groove 410 and a second accommodating groove 430 are provided in the housing 400 , and a third accommodating groove 231 and a fourth accommodating groove 233 are provided in the lens module 200 . Each of the receiving grooves is formed to extend to have a length in the optical axis direction.

The first accommodating groove 410 and the third accommodating groove 231 are formed to face each other in a direction perpendicular to the optical axis direction, and a space between the first accommodating groove 410 and the third accommodating groove 231 is the first accommodating groove. function as a space. In addition, the second accommodating groove 430 and the fourth accommodating groove 233 are formed to face each other in a direction perpendicular to the optical axis direction, and the space between the second accommodating groove 430 and the fourth accommodating groove 233 is the second. 2 It functions as an accommodation space.

The first ball member 600 is disposed between the first receiving groove 410 and the third receiving groove 231 , and the second ball member 700 is the second receiving groove 430 and the fourth receiving groove 233 . ) are placed between

The first accommodating groove 410 , the second accommodating groove 430 , and the third accommodating groove 231 have an approximately '∨' cross-section, and the fourth accommodating groove 233 has an approximately '￢' cross-section.

Accordingly, the first ball member 600 may make two-point contact with the first accommodating groove 410 and may make two-point contact with the third accommodating groove 231 . In addition, the second ball member 700 may make two-point contact with the second accommodating groove 430 , and may make one-point contact with the fourth accommodating groove 233 .

That is, the first ball member 600 may be in four-point contact with the opponent, and the second ball member 700 may be in three-point contact with the opponent.

The first ball member 600 accommodated in the space between the first accommodating groove 410 and the third accommodating groove 231 may function as a main guide, and the second accommodating groove 430 and the fourth accommodating groove ( 233 ) The second ball member 700 accommodated in the space may function as an auxiliary guide.

The present invention uses a closed-loop control method for detecting and feeding back the position of the lens module 200 .

Accordingly, the position detection unit 350 is provided for closed-loop control. The position detector 350 may be a Hall sensor, and may be disposed at the center of the coil 320 . The position detection unit 350 may be integrally formed with a driver IC that applies power to the coil 320 .

Meanwhile, a yoke 340 is disposed on the other surface of the substrate 330 . Accordingly, the yoke 340 is disposed to face the magnet 310 in a direction perpendicular to the optical axis direction with the coil 320 interposed therebetween.

The yoke 340 is a material capable of generating an attractive force between the magnet 310 and, accordingly, the attractive force acts between the yoke 340 and the magnet 310 in a direction perpendicular to the optical axis direction.

Accordingly, the first ball member 600 and the second ball member 700 are pressed by the attractive force between the yoke 340 and the magnet 310, and accordingly, the first ball member 600 and the second ball member ( The 700 may maintain a contact state with the lens module 200 and the housing 400 .

FIG. 3 is a view for explaining a case in which a tilt occurs while the lens module is moved, and FIG. 4 is a cross-sectional view taken along line II′ of FIG. 1 .

Also, FIG. 5 is a view showing a modified example of FIG. 4 , and FIG. 6 is a view showing another modified example of FIG. 4 .

7 is a perspective view of a housing according to an embodiment of the present invention.

First, referring to FIG. 3 , in the case of a general camera module capable of focusing, a plurality of ball bearings B1 and B2 are disposed on both sides of the magnet M, respectively.

The yoke is disposed to face the magnet (M) in a direction perpendicular to the optical axis direction, the yoke is a fixed member, and the magnet (M) is a movable member, so the magnet (M) by the attractive force acting between the magnet (M) and the yoke ) is pulled towards the yoke. Accordingly, the lens module L on which the magnet M is mounted is also pulled toward the yoke.

Accordingly, by the attractive force between the magnet M and the yoke, the plurality of ball bearings B1 and B2 come into contact with the lens module L and the housing H. In this state, the plurality of ball bearings B1 and B2 support the lens module L when the lens module L is moved in the optical axis direction.

Meanwhile, when all of the plurality of ball bearings B1 and B2 have the same size, all the ball bearings contact the lens module L, so that the lens module L may be stably supported.

That is, as shown in FIG. 3 , when all three ball bearings B1 and B2 disposed on both sides of the magnet M contact the lens module L and the housing H, the lens module L ) can be stably supported.

However, it is very difficult to physically make the sizes of the plurality of ball bearings B1 and B2 exactly the same. Accordingly, even when it is intended to manufacture all of the plurality of ball bearings B1 and B2 in the same size, the sizes of the plurality of ball bearings B1 and B2 actually manufactured may be different from each other.

As such, when there is a slight difference in the sizes of the plurality of ball bearings B1 and B2, only some of the balls come into contact with the lens module L, and accordingly, when the lens module L is moved in the optical axis direction There is a possibility that a tilt may occur.

In order to prevent the tilt (Tilt) from occurring during the movement of the lens module (L), the center point (C) of the attractive force acting between the magnet (M) and the yoke is a plurality of ball bearings (B1, B2) and The contact points of the lens module (L or housing (H)) should be located in the support area (A) connected to each other.

However, when only some of the plurality of ball bearings B1 and B2 come into contact with the lens module L, the center point C of the force of attraction is the support region during the movement of the lens module L. (A) may be placed outside the

In this case, the position of the lens module L is shifted in the course of the movement of the lens module L, and there is a fear that a tilt may occur.

4, in the present invention, the first ball member 600 and the second ball member 700 are disposed on both sides of the magnet 310, the first ball member 600 and the second ball member 700 Each includes a plurality of balls arranged along the optical axis direction.

In the camera module according to an embodiment of the present invention, the size (eg, diameter) of some of the plurality of balls is intentionally formed to be larger than the size (eg, diameter) of the remaining balls. In this case, balls having a large size among the plurality of balls may be intentionally brought into contact with the lens module 200 .

For example, the size of the balls disposed at the uppermost and the lower side in the optical axis direction among the plurality of balls is formed to be larger than the size of the balls located therebetween.

Among the plurality of balls of the first ball member 600 , the balls 610 and 630 disposed at the uppermost and lower sides in the optical axis direction are larger in size than the balls 620 located therebetween. In addition, the plurality of balls 710 and 720 of the second ball member 700 have sizes corresponding to each other.

Among the plurality of balls of the first ball member 600 , the balls 610 and 630 disposed at the uppermost and lowermost positions in the optical axis direction and the plurality of balls 710 and 720 of the second ball member 700 have sizes corresponding to each other. can have

The number of the plurality of balls of the first ball member 600 is different from the number of the plurality of balls of the second ball member 700 . For example, the number of the plurality of balls of the first ball member 600 is greater than the number of the plurality of balls of the second ball member 700 . In this embodiment, the first ball member 600 includes three balls, and the second ball member 700 includes two balls.

In the case of the first ball member 600, the balls 610 and 630 disposed at the uppermost and lowermost positions in the optical axis direction among the plurality of balls are in contact with the lens module 200, and in the case of the second ball member 700, All of the plurality of balls 710 and 720 come into contact with the lens module 200 (ie, four-point support).

In this case, the support area SA connecting the contact point between the first ball member 600 and the lens module 200 and the contact point between the second ball member 700 and the lens module 200 has a rectangular shape (eg, trapezoid).

Accordingly, by intentionally bringing some balls into contact with the lens module 200 , the attractive force between the magnet 310 and the yoke 340 within the support area SA connecting the contact points of some balls and the lens module 200 . The center of action (C) can be located.

Meanwhile, among the plurality of balls of the first ball member 600 , the balls 610 and 630 disposed at the uppermost and lowermost positions in the optical axis direction and the plurality of balls 710 and 720 of the second ball member 700 correspond to each other. Even if it is manufactured to have a suitable size, the actual manufactured size may be different from each other.

In this case, among the plurality of balls of the first ball member 600 , the balls 610 and 630 disposed at the uppermost and lowermost positions in the optical axis direction are in contact with the lens module 200 , and the plurality of balls of the second ball member 700 are in contact with the lens module 200 . Any one of the balls of may be in contact with the lens module 200 (ie, three-point support).

In this case, the support area SA connecting the contact point between the first ball member 600 and the lens module 200 and the contact point between the second ball member 700 and the lens module 200 may have a triangular shape. Accordingly, the support area SA may be reduced compared to the case of the four-point support.

However, in the present invention, even when the support area SA has a triangular shape, the center point C of the attractive force between the magnet 310 and the yoke 340 may be located within the support area SA.

In the present invention, the size of the first accommodating space in which the first ball member 600 is accommodated in the optical axis direction is different from the size in the optical axis direction of the second receiving space in which the second ball member 700 is accommodated.

For example, the size of the first accommodating space in the optical axis direction is larger than the size of the second accommodating space in the optical axis direction.

Accordingly, the distance D1 between the centers of the balls 610 and 630 disposed at the uppermost and lowermost positions in the optical axis direction among the plurality of balls of the first ball member 600 accommodated in the first accommodating space, and the second accommodating space The distance D2 between the centers of the balls 710 and 720 disposed at the uppermost and lowermost positions in the optical axis direction among the plurality of balls of the second ball member 700 accommodated in the second ball member 700 is formed differently.

For example, the distance D1 between the centers of the balls 610 and 630 disposed at the uppermost and lowermost positions in the optical axis direction among the plurality of balls of the first ball member 600 is the second ball accommodated in the second accommodating space. It is longer than the distance D2 between the centers of the balls 710 and 720 disposed at the uppermost and lowermost positions in the optical axis direction among the plurality of balls of the member 700 .

The housing 400 includes a first protrusion 411 protruding toward the first ball member 600 and a second protrusion 431 protruding toward the second ball member 700 .

Here, the first protrusion 411 and the second protrusion 431 are formed to have different lengths in the optical axis direction. For example, the length of the second protrusion 431 in the optical axis direction is longer than the length of the first protrusion 411 in the optical axis direction.

As shown in FIG. 4 , when viewed from a direction perpendicular to the optical axis, the second ball member 700 is higher than the ball 630 disposed at the lowermost position in the optical axis direction among the plurality of balls of the first ball member 600 . Among the plurality of balls of , the lowermost ball 720 in the optical axis direction is disposed at a higher position.

Accordingly, even if the support area SA connecting the contact point of the first ball member 600 and the lens module 200 and the contact point of the second ball member 700 and the lens module 200 has a triangular shape, the triangular All angles formed by each side may have acute angles.

Accordingly, even when the support area SA has a triangular shape, the center point C of the attractive force between the magnet 310 and the yoke 340 can be located within the support area SA, so that the lens module 200 It is possible to effectively prevent a tilt from occurring during the movement process.

The case 100 is provided with a third protrusion 110 protruding toward the first ball member 600 and a fourth protrusion 120 protruding toward the second ball member 700 .

Here, the third protrusion 110 and the fourth protrusion 120 are formed to have different lengths in the optical axis direction. For example, the length of the fourth protrusion 120 in the optical axis direction is longer than the length of the third protrusion 110 in the optical axis direction.

As shown in FIG. 4 , when viewed from a direction perpendicular to the optical axis, the second ball member 700 is higher than the ball 610 disposed at the uppermost position in the optical axis direction among the plurality of balls of the first ball member 600 . Among the plurality of balls, the ball 710 disposed at the uppermost position in the optical axis direction is disposed at a lower position.

Accordingly, even if the support area SA connecting the contact point of the first ball member 600 and the lens module 200 and the contact point of the second ball member 700 and the lens module 200 has a triangular shape, the triangular All angles formed by each side may have acute angles.

Accordingly, even when the support area SA has a triangular shape, the center point C of the attractive force between the magnet 310 and the yoke 340 can be located within the support area SA, so that the lens module 200 It is possible to effectively prevent a tilt from occurring during the movement process.

Meanwhile, referring to FIG. 5 , as another embodiment of the present invention, the first ball member 600 ′ may include four balls, and the second ball member 700 may include two balls. .

Even in this case, the first ball member 600' is larger in size than the balls 620' and 630' in which the uppermost and lower balls 610' and 640' in the optical axis direction among the four balls are located therebetween. , the two balls of the second ball member 700 have sizes corresponding to each other.

Accordingly, the support area SA connecting the contact point between the first ball member 600 ′ and the lens module 200 and the contact point between the second ball member 700 and the lens module 200 has a rectangular shape or a triangular shape. Even though it has a shape, since the angles formed by each side of the triangle are all acute angles, the center point C of the attractive force between the magnet 310 and the yoke 340 may be within the support area SA.

Referring to FIG. 6 , as another embodiment of the present invention, the first ball member 600 ′ may include four balls, and the second ball member 700 ′ may include three balls. .

The first ball member 600' is larger in size than the balls 620' and 630', in which the uppermost and lowermost balls 610' and 640' in the optical axis direction among the four balls are located therebetween, and the second ball The member 700' is larger than the ball 720' in which the uppermost and lowermost balls 710' and 730' in the optical axis direction among the three balls are positioned therebetween.

Accordingly, the support area SA connecting the contact point between the first ball member 600 ′ and the lens module 200 and the contact point between the second ball member 700 ′ and the lens module 200 has a rectangular shape, or Even if it has a triangular shape, since all angles formed by each side of the triangle are acute angles, the center of attraction between the magnet 310 and the yoke 340 may be located within the support area SA.

Through the above embodiments, the camera module according to an embodiment of the present invention may prevent a tilt from occurring when the lens module is moved in the optical axis direction.

In the above, the configuration and features of the present invention have been described based on the embodiments according to the present invention, but the present invention is not limited thereto, and it is understood that various changes or modifications can be made within the spirit and scope of the present invention. It is intended that such changes or modifications will be apparent to those skilled in the art, and therefore fall within the scope of the appended claims.

100: case 200: lens module
210: lens barrel 230: carrier
300: driving unit 310: magnet
320: coil 330: substrate
340: yoke 350: position detection unit
400: housing 500: image sensor module
510: image sensor 530: printed circuit board

Claims (14)

a lens module having a plurality of lenses;
a housing accommodating the lens module;
a driving unit including a magnet provided in the lens module and a coil disposed to face the magnet;
a yoke generating attractive force with respect to the magnet; and
It includes; a first ball member and a second ball member disposed between the lens module and the housing and pressed by the attractive force;
The housing is provided with a first protrusion protruding toward the first ball member and a second protrusion protruding toward the second ball member,
The first protrusion and the second protrusion have different lengths in an optical axis direction.
According to claim 1,
The first ball member and the second ball member each include a plurality of balls disposed along the optical axis direction,
A camera module with some of the plurality of balls having a larger diameter than the remaining balls.
3. The method of claim 2,
The distance between the centers of the balls disposed at the uppermost and lowermost positions in the optical axis direction among the plurality of balls of the first ball member,
A camera module different from the distance between the centers of the balls disposed at the uppermost and lowermost positions in the optical axis direction among the plurality of balls of the second ball member.
3. The method of claim 2,
A camera module in which the number of the plurality of balls of the first ball member is different from the number of the plurality of balls of the second ball member.
5. The method of claim 4,
Among the plurality of balls of the first ball member, the balls disposed at the uppermost and lowermost positions in the optical axis direction have a first diameter, and a ball positioned therebetween has a second diameter, and the first diameter is greater than the second diameter. big,
The diameter of the plurality of balls of the second ball member is greater than the second diameter of the camera module.
5. The method of claim 4,
The plurality of balls of the first ball member and the plurality of balls of the second ball member have a diameter larger than a ball between the balls disposed at the uppermost and lowermost sides in the optical axis direction, respectively.
According to claim 1,
It further includes; a case coupled to the housing;
The case is provided with a third protrusion protruding toward the first ball member and a fourth protrusion protruding toward the second ball member.
8. The method of claim 7,
The third protrusion and the fourth protrusion have different lengths in the optical axis direction.
According to claim 1,
A first accommodation space in which the first ball member is accommodated and a second accommodation space in which the second ball member is accommodated are provided between the lens module and the housing,
The length of the first accommodating space in the optical axis direction is different from the length of the second accommodating space in the optical axis direction.
a housing having a first accommodating groove and a second accommodating groove;
a lens module accommodated in the housing and having a third accommodating groove facing the first accommodating groove and a fourth accommodating groove facing the second accommodating groove;
a first ball member disposed between the first accommodating groove and the third accommodating groove and including a plurality of balls disposed along an optical axis direction; and
a second ball member disposed between the second accommodating groove and the fourth accommodating groove, the second ball member including a plurality of balls arranged along the optical axis direction;
The number of the plurality of balls of the first ball member is different from the number of the plurality of balls of the second ball member,
The length in the optical axis direction of the surface where the first accommodation groove and the third accommodation groove face each other is different from the length in the optical axis direction of the surface in which the second accommodation groove and the fourth accommodation groove face each other module.
11. The method of claim 10,
The housing is provided with a first protrusion protruding toward the first ball member and a second protrusion protruding toward the second ball member,
The first protrusion and the second protrusion have different lengths in the optical axis direction.
11. The method of claim 10,
It further includes; a case coupled to the housing;
The case is provided with a third protrusion protruding toward the first ball member and a fourth protrusion protruding toward the second ball member,
The third protrusion and the fourth protrusion have different lengths in the optical axis direction.
11. The method of claim 10,
The first ball member comprises at least three balls,
Among the at least three balls, the uppermost and lowermost balls in the optical axis direction have a larger diameter than the balls located therebetween.
11. The method of claim 10,
a driving unit including a magnet provided in the lens module and a coil disposed to face the magnet; and
The camera module further comprising a; yoke for generating an attractive force with respect to the magnet.

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