Voice coil motor
A VCM is disclosed, the motor including a stator including a first driving unit, a rotor arranged inside the stator, including a second driving unit responding to the first driving unit and mounted therein with a lens, a base fixing the stator, and an elastic member coupled to the rotor to float the rotor from the base in a case a driving signal for driving the first and second driving units is not applied to the first and second driving units.
1. A voice coil motor comprising:
a stator including a first driving unit;
a rotor disposed in the stator and, including a second driving unit interacting with the first driving unit;
a base fixing the stator; and
an elastic member distancing the rotor from the base at an initial position when no current is applied to the first or second driving unit,
wherein the elastic member includes a first elastic member coupled to a lower surface of the rotor and a second elastic member coupled to an upper surface of the rotor, and
wherein a spring constant of the first elastic member is different from that of the second elastic member.
2. The voice coil motor of claim 1 , wherein the rotor moves from the initial position in a first direction toward the base or in a second direction distancing from the base.
3. The voice coil motor of claim 2 , further comprising a cover disposed over the rotor, wherein the cover includes an upper plate having an opening and a lateral plate extended to a direction facing the base from an edge of the upper plate.
4. The voice cod motor of claim 3 , wherein the cover surrounds the first or second driving unit and is coupled to the base.
5. The voice coil motor of claim 2 , wherein the spring constant of the first elastic member is greater than that of the second elastic member.
6. The voice coil motor of claim 5 , wherein a cross section of the first elastic member is smaller than that of the second elastic member.
7. The voice coil motor of claim 2 , wherein the first driving unit includes a magnet and the second driving unit includes a coil.
8. The voice coil motor of claim 2 , wherein the first driving unit includes a coil and the second driving unit includes a magnet.
9. The voice coil motor of claim 2 , wherein the first elastic member comprises a first inner portion, a first outer portion, and a first connection portion connecting the first inner portion and the first outer portion, and
wherein the second elastic member comprises a second inner portion, a second outer portion, and a second connection portion connecting the second inner portion and the second outer portion.
10. The voice coil motor of claim 9 , wherein a length of the first connection portion is different from that of the second connection portion.
11. The voice coil motor of the claim 10 , wherein the length of the first connection portion is shorter than that of the second connection portion.
12. The voice coil motor of the claim 10 , wherein the length of the first connection portion is longer than that of the second connection portion.
13. The voice coil motor of claim 9 , wherein a shape of the first connection portion is different from that of the second connection portion.
14. The voice coil motor of claim 2 , wherein the first or second direction is determined by a direction of a current to the first or second driving unit.
15. The voice coil motor of claim 14 , wherein the first elastic member includes a pair of elastic members.
16. The voice coil motor of claim 2 , wherein the spring constant of the second elastic member is greater than that of the first elastic member.
17. The voice coil motor of claim 2 , wherein the spring constant of the first elastic member is different from that of the second elastic member such that a tilt, generated by a gravity center of the rotor while the rotor is driven, is inhibited.
18. The voice coil motor of claim 1 , further comprising a shock absorption member disposed on the base.
19. The voice coil motor of claim 18 , wherein the shock absorption member includes any one material selected from a group of a sponge, a synthetic rubber having, elasticity and a rubber.
20. A camera comprising an image sensor, a lens, and a voice coil motor,
wherein the voice coil motor comprises:
a stator including a first driving unit;
a rotor disposed in the stator and including a second driving unit;
a base fixing the stator; and
an elastic member distancing the rotor from the base at an initial position when no current is applied to the first or second driving unit,
wherein the elastic member includes a first elastic member coupled to a lower surface of the rotor and a second elastic member coupled to an upper surface of the rotor;
wherein the first elastic member comprises a first inner portion, a first outer portion, and a first connection portion connecting the first inner portion and the first outer portion;
wherein the second elastic member comprises a second inner portion, a second outer portion, and a second connection portion connecting the second inner portion and the second outer portion, and
wherein a spring constant of the first connection portion is different from that of the second connection portion.
21. The camera of claim 20 , wherein each spring constant of the first and second connection portions is determined by shape, thickness, length, or dimension of the first and second connection portions.
22. The camera of claim 20 , wherein a length of the first connection portion is different from that of the second connection portion.
23. The camera of claim 22 , wherein the length of the first connection portion is shorter than that of the second connection portion.
24. The camera of claim 22 , wherein the length of the first connection portion is longer than that of the second connection portion.
25. The camera of claim 20 , wherein a shape of the first connection portion is different from that of the second connection portion.