Plastic barrel, imaging lens module and electronic device

1. A plastic barrel, comprising:

an object-end portion comprising:

an outer object-end surface;

an object-end hole; and

an inner annular object-end surface connected to the outer object-end surface and surrounding the object-end hole;

an image-end portion comprising:

an outer image-end surface;

an image-end opening; and

an inner annular image-end surface connected to the outer image-end surface and surrounding the image-end opening;

a tube portion connecting the object-end portion and the image-end portion, wherein the tube portion comprises:

a plurality of inclined surfaces, wherein an angle is between each of the inclined surfaces and a central axis of the plastic barrel; and

a plurality of wedge structures, which are disposed on at least one surface of the inner annular object-end surface, the inner annular image-end surface and the inclined surfaces, wherein the wedge structures are regularly arranged around the central axis, and each of the wedge structures is linearly disposed along a direction from the outer object-end surface toward the outer image-end surface and comprises:

an acute end; and

a tapered section connecting the surface, which the wedge structure is disposed on, and the acute end.

2. The plastic barrel of claim 1 , wherein the plastic barrel with the wedge structures is formed integrally.

3. The plastic barrel of claim 2 , wherein an angle between any two wedge structures adjacent to each other is θ, and the following condition is satisfied:

35 degrees <θ<90 degrees.

4. The plastic barrel of claim 3 , wherein the angle between any two wedge structures adjacent to each other is θ, and the following condition is satisfied:

45 degrees <θ<75 degrees.

5. The plastic barrel of claim 3 , wherein an angle between the inner annular image-end surface and the central axis is α, and the following condition is satisfied:

1. 0 degrees <α<27.0 degrees.

6. The plastic barrel of claim 5 , wherein the angle between the inner annular image-end surface and the central axis is α, and the following condition is satisfied:

3. 0 degrees <α<19.0 degrees.

7. The plastic barrel of claim 2 , wherein the outer image-end surface comprises a light diminishing surface, a surface roughness of the light diminishing surface is Ra, and the following condition is satisfied:

0. 1 μm <Ra <4.0 μm.

8. The plastic barrel of claim 2 , wherein the wedge structures are only disposed on the inner annular image-end surface.

9. The plastic barrel of claim 2 , wherein a number of the wedge structures is greater than or equal to 80, and smaller than or equal to 420.

10. The plastic barrel of claim 9 , wherein the number of the wedge structures is greater than or equal to 150, and smaller than or equal to 360.

11. The plastic barrel of claim 2 , wherein an entire surface of the acute end and an entire surface of the tapered section of each of the wedge structures are both smooth surfaces.

12. The plastic barrel of claim 2 , wherein the tube portion further comprises:

a plurality of parallel surfaces parallel to the central axis, wherein a number of the parallel surfaces is at least six.

13. The plastic barrel of claim 1 , wherein an outer diameter of the image-end portion is greater than a distance parallel to the central axis between the outer object-end surface and the outer image-end surface.

14. The plastic barrel of claim 1 , wherein a cross-section orthogonal to the central axis of each of the wedge structures is isosceles triangle.

15. The plastic barrel of claim 1 , wherein a distance between the surface, which the wedge structure is disposed on, and the acute end of each of the wedge structures is h, and the following condition is satisfied:

0. 03 mm <h <0.25 mm.

16. The plastic barrel of claim 1 , wherein a distance between the surface, which the wedge structure is disposed on, and the acute end of each of the wedge structures is h, and the following condition is satisfied:

0. 04 mm <h <0.15 mm.

17. An imaging lens module, comprising:

the plastic barrel of claim 1 ; and

an optical lens assembly disposed in the plastic barrel and comprising at least one lens element.

18. The imaging lens module of claim 17 , wherein the object-end hole of the plastic barrel is an aperture stop of the optical lens assembly.

19. The imaging lens module of claim 17 , wherein the wedge structures are not in contact with the optical lens assembly.

20. An electronic device, comprising:

the imaging lens module of claim 17 .