Optical driving mechanism

1. An optical driving mechanism, comprising:

a holder connecting an optical element;

a fixed portion, wherein the holder moves relative to the fixed portion;

a first elastic element, wherein the holder is movably connected to the fixed portion via the first elastic element; and

a plurality of first adhesive elements, wherein the first elastic element is connected to the holder via the first adhesive elements,

wherein the first elastic element comprises:

a plurality of first strings;

a plurality of second strings;

a plurality of adhesive portions, wherein the first strings and the second strings are connected to the first adhesive elements via the adhesive portions;

a plurality of first fixed ends for the fixed portion, fixedly connected to the fixed portion;

a plurality of first fixed ends for the movable portion, fixedly connected to the holder; and

a plurality of first string roots, wherein each of the first string roots is located at a junction between one of the first strings and one of the second strings respectively,

wherein when viewed along an optical axis, one of the first string roots is connected to one of the first fixed ends for the fixed portions and one of the first fixed ends for the movable portions, and one of the first string roots is also connected to another one of the first fixed ends for the movable portions.

2. The optical driving mechanism as claimed in claim 1 , wherein the holder has a plurality of contact surfaces facing the adhesive portions.

3. The optical driving mechanism as claimed in claim 2 , wherein the first elastic element has a plate-like structure perpendicular to a direction of the optical axis, the adhesive portions and the contact surfaces at least partially overlap when viewed along the direction of the optical axis.

4. The optical driving mechanism as claimed in claim 1 , wherein the first strings and the second strings have strip structures.

5. The optical driving mechanism as claimed in claim 1 , further comprising a second elastic element, wherein the second elastic element comprises:

a plurality of second fixed ends for the fixed portion, fixedly connected to the fixed portion;

a plurality of second fixed ends for the movable portion, fixedly connected to the holder;

a plurality of third strings, wherein each of the second fixed ends for the movable portions is movably connected to one of the second fixed ends for the fixed portions via one of the third strings;

a plurality of second adhesive elements; and

a plurality of second string roots, wherein each of the second string roots is located at a junction between one of the second fixed ends for the movable portions and one of the third strings respectively;

wherein the second elastic element is connected to the holder via the second adhesive elements, and each of the second adhesive elements is adjacent to the second string roots respectively.

6. The optical driving mechanism as claimed in claim 5 , wherein the first adhesive element and the second adhesive element comprise UV resin.

7. The optical driving mechanism as claimed in claim 5 , wherein the first elastic element and the second elastic element comprise titanium copper.

8. The optical driving mechanism as claimed in claim 5 , wherein a thickness of the first elastic element is less than a thickness of the second elastic element.

9. The optical driving mechanism as claimed in claim 8 , wherein the thickness of the first elastic element is 0.03 mm.

10. The optical driving mechanism as claimed in claim 8 , wherein the thickness of the second elastic element is 0.04 mm.

11. The optical driving mechanism as claimed in claim 5 , wherein the holder is moved from an initial position to a first limiting position along a direction of the optical axis by the first elastic element and the second elastic element.

12. The optical driving mechanism as claimed in claim 11 , wherein the first elastic element and the second elastic element each have a predeformation when the holder is located in the initial position, and an amount of predeformation of the first elastic element and the second elastic element are different.

13. The optical driving mechanism as claimed in claim 11 , wherein the holder is moved from the initial position to a second limiting position along the direction of the optical axis by the first elastic element and the second elastic element.

14. The optical driving mechanism as claimed in claim 13 , wherein spring constants of the first elastic element and the second elastic element are substantially constant values when the holder is located in the second limiting position relative to the fixed portion.

15. The optical driving mechanism as claimed in claim 13 , wherein the second strings do not contact an upper portion of the holder when the holder is located in the second limiting position relative to the fixed portion, and the second strings contact the upper portion of the holder when the holder is located in the first limiting position relative to the fixed portion.

16. The optical driving mechanism as claimed in claim 13 , wherein there is a critical position between the initial position and the second limiting position, the first string roots contact an upper portion of the holder when the holder is located between the initial position and the critical position, and the first string roots do not contact the upper portion of the holder when the holder is located between the critical position and the second limiting position.

17. The optical driving mechanism as claimed in claim 13 , wherein the holder has a first displacement in the direction of the optical axis when the holder is located in the first limiting position relative to the fixed portion.

18. The optical driving mechanism as claimed in claim 17 , wherein the holder has a second displacement in the direction of the optical axis when the holder is located in the second limiting position relative to the fixed portion.

19. The optical driving mechanism as claimed in claim 18 , wherein the first displacement is less than the second displacement.