Optical element driving mechanism

1. An optical element driving mechanism, comprising:

a fixed part;

a movable part moving relative to the fixed part, wherein the movable part comprises:

a frame; and

a holder, wherein the frame and the holder are arranged along a main axis;

a driving assembly driving the movable part to move relative to the fixed part; and

a sensing assembly sensing a movement of the movable part, wherein the sensing assembly comprises:

a sensing element disposed on the frame, wherein the sensing element senses a movement of the holder relative to the frame; and

a reference element disposed on the holder, wherein when viewed along the main axis, the sensing element at least partially overlaps the reference element.

2. The optical element driving mechanism as claimed in claim 1 , wherein the holder comprises an electrical connection portion electrically connected to the driving assembly.

3. The optical element driving mechanism as claimed in claim 1 , further comprising a damping element disposed between the frame and the fixed part.

4. The optical element driving mechanism as claimed in claim 1 , further comprising a damping element disposed between the holder and the frame.

5. The optical element driving mechanism as claimed in claim 1 , wherein the fixed part and the sensing element are located a distance apart.

6. The optical element driving mechanism as claimed in claim 1 , wherein the fixed part comprises a recess corresponding to the sensing element.

7. The optical element driving mechanism as claimed in claim 1 , wherein when viewed along the main axis, a profile of the frame is polygonal and the sensing element is disposed on a corner or a side of the frame.

8. The optical element driving mechanism as claimed in claim 1 , further comprising a damping element disposed between the sensing element and the fixed part.

9. The optical element driving mechanism as claimed in claim 1 , wherein the sensing assembly further comprises at least another sensing element disposed on the fixed part for sensing a movement of the movable part relative to the fixed part.

10. The optical element driving mechanism as claimed in claim 1 , further comprising a stopping assembly close to the sensing element to prevent the sensing element from contacting the fixed part.

11. The optical element driving mechanism as claimed in claim 10 , wherein the stopping assembly is disposed on the fixed part or the frame.

12. The optical element driving mechanism as claimed in claim 1 , further comprising a plurality of stopping assemblies, wherein the sensing element is disposed between the stopping assemblies.

13. The optical element driving mechanism as claimed in claim 1 , wherein the movable part further comprises a circuit assembly disposed on the frame, and a portion of the circuit assembly is revealed from the frame.

14. The optical element driving mechanism as claimed in claim 13 , wherein the circuit assembly is three-dimensional.

15. The optical element driving mechanism as claimed in claim 13 , wherein the sensing element is electrically connected to the revealed portion of the circuit assembly.

16. The optical element driving mechanism as claimed in claim 13 , wherein the movable part further comprises a first elastic element connecting the frame and the holder, and the sensing element is electrically connected to the driving assembly via the first elastic element.

17. The optical element driving mechanism as claimed in claim 16 , wherein when viewed in a direction that is perpendicular to the main axis, the first elastic element at least partially overlaps the sensing element.

18. The optical element driving mechanism as claimed in claim 16 , wherein the movable part further comprises another elastic element connecting the first elastic element and the holder, the fixed part further comprises an external electrical connection portion, and the sensing element is electrically connected to the external electrical connection portion via the circuit assembly and the another elastic element.