Optical driving mechanism having curved connecting surface and assembly method for the same

1. An optical driving mechanism, comprising:

a fixed portion;

a movable portion, disposed on the fixed portion and including a holder and an optical element, wherein the holder is configured to sustain the optical element, and the optical element has a lens barrel and at least one lens; and

a driving assembly, configured to drive the movable portion to move relative to the fixed portion;

wherein a first connecting surface of the holder abuts a second connecting surface of the lens barrel, and at least one of the first connecting surface and the second connecting surface has a curved surface, wherein in the direction of an optical axis of the lens and in a direction perpendicular to the optical axis, the first connecting surface at least partially overlaps the second connecting surface;

wherein the holder comprises a hollow portion, for containing the lens barrel.

2. The optical driving mechanism as claimed in claim 1 , wherein the curved surface is not parallel to the optical axis.

3. The optical driving mechanism as claimed in claim 1 , wherein both the first connecting surface and the second connecting surface are curved surfaces.

4. The optical driving mechanism as claimed in claim 3 , wherein the radius of curvature of the first connecting surface is greater than or equal to the radius of curvature of the second connecting surface.

5. The optical driving mechanism as claimed in claim 1 , wherein the holder has a plurality of first connecting surfaces abutting the second connecting surface and surrounding the optical axis.

6. The optical driving mechanism as claimed in claim 5 , wherein at least two contact areas are formed between the first connecting surfaces and the second connecting surface.

7. The optical driving mechanism as claimed in claim 6 , wherein there is a gap between the first connecting surfaces.

8. The optical driving mechanism as claimed in claim 1 , wherein the second connecting surface has a curved surface, and the first connecting surface has an inclined structure which is inclined relative to the optical axis.

9. The optical driving mechanism as claimed in claim 1 , wherein the first connecting surface and the second connecting surface are located at a light incident end or a light exit end of the optical driving mechanism.

10. The optical driving mechanism as claimed in claim 1 , further comprising an adhesive disposed between the holder and the lens barrel of the optical element.

11. The optical driving mechanism as claimed in claim 10 , wherein the lens barrel has a recessed portion formed on the outer side of the lens barrel, and the adhesive is disposed in the recess portion and between the lens barrel and the holder.

12. The optical driving mechanism as claimed in claim 10 , wherein the holder has a receiving slot located at a light incident end of the optical driving mechanism, and the adhesive is disposed in the receiving slot.

13. The optical driving mechanism as claimed in claim 10 , wherein the inner side wall of the holder has a recess configured to receive the adhesive.

14. The optical driving mechanism as claimed in claim 10 , wherein the first connecting surface and the second connecting surface are located at either a light incident end or a light exit end of the optical driving mechanism, and the adhesive is located at the other of the light incident end or the light exit end.

15. An assembly method of an optical driving mechanism, comprising:

providing the optical driving mechanism as claimed in claim 10 ;

disposing the optical element in the holder;

applying the adhesive between the optical element and the holder;

orienting the optical axis of a lens of the optical element perpendicular to a reference surface of the fixed portion; and

curing the adhesive.