OPTICAL ELEMENT DRIVING MECHANISM

1 . An optical element driving mechanism, having an optical axis, comprising:

a fixed portion, having an opening;

a movable element, which is movable relative to the fixed portion;

a plurality of blades, connected to the movable element;

a driving assembly, driving the movable element to rotate around a rotating axis, comprising at least one magnetic element disposed on the movable element; and

a magnetically permeable element, having a magnetically permeable material, arranging in the fixed portion,

wherein when viewed along the rotating axis, the at least one magnetic element and the magnetically permeable element at least partially overlap.

2 . The optical element driving mechanism as claimed in claim 1 , further comprising a sensing assembly, sensing a motion of the movable element, comprising a sensing element disposed on the fixed portion,

wherein when viewed along the rotating axis, the sensing element does not overlap with the magnetically permeable assembly.

3 . The optical element driving mechanism as claimed in claim 2 , wherein the at least one magnetic element has a plurality of magnetic units with arc structures.

4 . The optical element driving mechanism as claimed in claim 3 , wherein each of the magnetic units has an N-pole and an S-pole, and a magnetic pole direction of the magnetic unit is parallel to the rotating axis.

5 . The optical element driving mechanism as claimed in claim 4 , wherein the driving assembly further comprises a driving coil set fixed to the fixed portion.

6 . The optical element driving mechanism as claimed in claim 5 , wherein the magnetic units are arranged along a first imaginary line and formed two magnetic pole surfaces,

wherein the two magnetic pole surfaces are opposite each other, and one of the magnetic pole surfaces faces the driving coil set,

wherein the first imaginary line is arc-shaped and perpendicular to the optical axis, and the first imaginary line does not intersect the optical axis,

wherein each of the magnetic units is a permanent magnet.

7 . The optical element driving mechanism as claimed in claim 5 , wherein a number of the at least one magnetic element is two, and two magnetic elements with arc shape are disposed symmetrically to the optical axis,

wherein the driving coil set has two driving coils, when viewed along the rotating axis, the two driving coils are located on both sides of the optical axis and symmetrical to the optical axis,

wherein each winding axis of the two driving coils is parallel to the rotating axis and respectively passes through one of the two magnetic elements.

8 . The optical element driving mechanism as claimed in claim 5 , wherein a number of the at least one magnetic element is three,

wherein the driving coil set has three driving coils, when viewed along the rotating axis, a shortest distance between one driving coil and another driving coil is approximately equal to a shortest distance between the one driving coil and other driving coil,

wherein each winding axis of the three driving coils is parallel to the rotating axis and respectively passes through one of three magnetic elements.

9 . The optical element driving mechanism as claimed in claim 8 , wherein when viewed along the rotating axis, the sensing element does not overlap with the three driving coils.

10 . The optical element driving mechanism as claimed in claim 2 , wherein the fixed portion comprises a base, and the base has a first concave portion accommodating the magnetically permeable element, and a depth of the first concave portion is greater than a thickness of the magnetically permeable element.

11 . The optical element driving mechanism as claimed in claim 10 , wherein the magnetic permeable element has an accommodating portion for accommodating part of the sensing element, and the accommodating portion passes through the magnetically permeable element along the rotating axis.

12 . The optical element driving mechanism as claimed in claim 11 , wherein the base further has a second concave portion accommodating part of the sensing element, and the second concave portion passes through the first concave portion along the rotating axis,

wherein when viewed along the rotating axis, the second concave portion and the accommodating portion at least partially overlap.

13 . The optical element driving mechanism as claimed in claim 12 , wherein the base further has a third concave portion accommodating a driving coil set of the driving assembly,

wherein when viewed along a direction that is perpendicular to the rotating axis, a bottom surface of the third concave portion is closer to a light incident surface than a bottom surface of the first concave portion.

14 . The optical element driving mechanism as claimed in claim 13 , wherein a distance between the bottom surface of the third concave portion and the bottom surface of the first concave portioned portion is greater than the thickness of the magnetically permeable element.

15 . The optical element driving mechanism as claimed in claim 14 , further comprising a circuit assembly, disposed on the fixed potion and between the magnetic permeable element and the driving coil set.

16 . The optical element driving mechanism as claimed in claim 3 , wherein a rotation limiting range of the movable element is smaller than a length of anyone of the magnetic units.

17 . The optical element driving mechanism as claimed in claim 3 , wherein when the movable element is located at an initial position and viewed along the rotating axis, the sensing element overlaps a boundary of the two magnetic units.

18 . The optical element driving mechanism as claimed in claim 3 , wherein the sensing assembly further comprises a sensing magnetic element disposed on the movable element, the sensing element senses a magnetic field of the sensing magnetic element on the movable element to obtain a position of the movable element relative to the fixed portion.

19 . The optical element driving mechanism as claimed in claim 17 , wherein the magnetic element is be used as the sensing magnetic element at the same time.

20 . The optical element driving mechanism as claimed in claim 17 , wherein when viewed along the rotating axis, the at least one magnetic element and the sensing element at least partially overlap.