Camera module

1. A camera module, comprising:

a first lens group on which light is incident;

a second lens group disposed so as to be spaced apart from the first lens group in an optical-axis direction;

a third lens group disposed between the first lens group and the second lens group;

a first mover configured to move the second lens group in the optical-axis direction;

a second mover configured to move the third lens group in the optical-axis direction;

a base accommodating the first mover and the second mover;

a first support ball disposed to be in rolling contact with the first mover and the base, the first support ball supporting movement of the first mover relative to the base;

a second support ball disposed to be in rolling contact with the second mover and the base, the second support ball supporting movement of the second mover relative to the base;

a driving magnet coupled to each of the first mover and the second mover; and

a coil part coupled to the base, the coil part being disposed to face the driving magnet,

wherein the coil part comprises:

a yoke disposed in the base, the yoke comprising long sides and short sides, the long sides being disposed to be oriented in the optical-axis direction; and

a moving coil disposed to face the driving magnet, the moving coil being wound on the short sides of the yoke, and

wherein an entirety of a surface of the driving magnet that faces the moving coil serves as a first pole, and

wherein a portion of the first mover extends along a portion of the second mover in the optical-axis direction.

2. The camera module according to claim 1 , wherein each of the first mover and the second mover comprises a first groove formed in a portion thereof that faces the base, each of the first grooves being disposed such that a longitudinal direction thereof is oriented in the optical-axis direction,

wherein the base comprises a second groove formed therein at a position corresponding to a position of each of the first grooves of the first mover and the second mover, each of the second grooves having a shape corresponding to a shape of the corresponding first groove of the first mover and the second mover,

wherein the first support ball is disposed in a space formed by the first groove of the first mover and the corresponding second groove of the base, and

wherein the second support ball is disposed in a space formed by the first groove of the second mover and the corresponding second groove of the base.

3. The camera module according to claim 2 , wherein at least one of the first grooves or the second grooves comprises:

at least one stopper formed to protrude therefrom to limit a moving distance of the first and second support balls in the optical-axis direction.

4. The camera module according to claim 3 , wherein the base comprises a pair of protruding portions spaced apart from each other in a direction perpendicular to the optical-axis direction and disposed such that a longitudinal direction thereof is oriented in the optical-axis direction, and

wherein each of the protruding portions includes one of the second grooves of the base.

5. The camera module according to claim 4 , wherein the second groove of each of the protruding portions is formed as a plurality of second groves to be located in each of upper portions and lower portions of the protruding portions, and

wherein each of the first grooves of the first and second movers is formed as a plurality of first grooves in each of upper portions and lower portions of the first mover and the second mover.

6. The camera module according to claim 4 , wherein the coil part is disposed in each of the protruding portions, and is spaced apart from the first groove and the second groove in a direction perpendicular to the optical-axis direction.

7. The camera module according to claim 4 , wherein the stopper is not formed in the second groove formed in a lower portion of the protruding portion.

8. The camera module according to claim 2 , wherein the first and second support balls are inserted into a respective first groove of the first and second movers.

9. The camera module according to claim 2 , wherein a cross-section of each of the first groove and the second groove is formed such that a width thereof gradually increases toward an opening thereof.

10. The camera module according to claim 2 , wherein any one of the first groove and the second groove is formed such that a width thereof gradually increases toward an opening thereof, and

wherein a remaining one of the first groove and the second groove is formed such that a width of the opening thereof and a width of an inner portion thereof are the same.

11. The camera module according to claim 1 , further comprising:

a sensing magnet disposed at a lower portion of each of the first mover and the second mover; and

a position sensor disposed to face the sensing magnet.

12. The camera module according to claim 11 , wherein each of the sensing magnet and the position sensor is provided in a plural number in the optical-axis direction.

13. The camera module according to claim 12 , further comprising:

a printed circuit board coupled to a bottom surface of the base,

wherein the position sensor is coupled to the printed circuit board.

14. The camera module according to claim 13 , wherein the base comprises a through-hole formed in a portion thereof at which the position sensor is disposed, the sensing magnet and the position sensor facing each other through the through-hole.

15. The camera module according to claim 11 , wherein the first mover comprises:

a first member disposed such that a longitudinal direction thereof is oriented in the optical-axis direction, the driving magnet and the sensing magnet being mounted to the first member; and

a second member protruding from the first member in a direction perpendicular to the optical-axis direction, and the second lens group being coupled to the second member.

16. The camera module according to claim 11 , wherein the sensing magnet is spaced apart from the driving magnet.

17. The camera module according to claim 11 , wherein the driving magnet is disposed on a side surface of each of the first mover and the second mover, and

wherein the sensing magnet and the driving magnet are spaced apart from each other in an upward-downward direction, perpendicular to the optical-axis direction.

18. The camera module according to claim 11 , wherein the position sensor and the coil part are disposed to be spaced apart from each other.

19. The camera module according to claim 11 , wherein the sensing magnet moves together with the first and second movers.

20. The camera module according to claim 1 , wherein the base includes a mounting portion, to which the first lens group is securely coupled.