Optical lens and light source module

1. An optical lens, having a top surface, a bottom surface and a plurality of side surfaces, wherein the top surface is opposite to the bottom surface, and the top surface is connected to the bottom surface through the side surfaces, comprising:

a light incident portion, comprising:

two rear optical surfaces;

a first light incident surface; and

two second light incident surfaces, wherein each of the two second light incident surfaces has a first side edge and a second side edge opposite to each other, the first light incident surface is connected to each of the second light incident surfaces through the first side edge of each of the second light incident surfaces, each of the rear optical surfaces is connected to each of the second light incident surfaces through the second side edge of each of the second light incident surfaces; and

a light guiding portion, having a plurality of light guiding branches, and the light guiding branches extending along different extending directions, wherein each of the light guiding branches has a main light emitting surface, and the first light incident surface and the second light incident surfaces face the main light emitting surfaces of the light guiding branches, respectively,

wherein the first light incident surface and the bottom surface have a first included angle there between, and the first included angle is between 90° and 160°, or each of the side surfaces and the bottom surface have a second included angle there between, and the second included angle is between 20° and 90°.

2. The optical lens as claimed in claim 1 , wherein the top surface has a plurality of top surface branches, the bottom surface has a plurality of bottom surface branches, the bottom surface branches respectively correspond to the top surface branches, and surfaces of one of the light guiding branches are formed by the corresponding top surface branch and the bottom surface branch and part of the side surfaces.

3. The optical lens as claimed in claim 2 , wherein contours of orthogonal projections of the top surface and the bottom surface on a reference plane are similar to each other, and an area of the contour of the orthogonal projection of the top surface on the reference plane is smaller than an area of the contour of the orthogonal projection of the bottom surface on the reference plane.

4. The optical lens as claimed in claim 2 , wherein the top surface and the bottom surface respectively have a T-shape contour.

5. The optical lens as claimed in claim 2 , wherein the side surface facing the first light incident surface or each of the second light incident surfaces is the main light emitting surface of each of the light guiding branches, and the main light emitting surface of each of the light guiding branches is a trapezoid.

6. The optical lens as claimed in claim 2 , wherein the bottom surface is connected with the rear optical surfaces, the first light incident surface and the second light incident surfaces to form an accommodating space.

7. The optical lens as claimed in claim 2 , wherein the rear optical surfaces are perpendicular to the bottom surface.

8. A light source module, comprising at least one light emitting unit, and each of the light emitting units comprising:

the optical lens as claimed in claim 1 ; and

a light emitting element, adapted to provide a light beam, wherein the light beam enters the optical lens through the first light incident surface and the second light incident surfaces of the optical lens, and the light beam leaves the optical lens through the main light emitting surfaces of the light guiding branches.

9. The light source module as claimed in claim 8 , wherein the number of the at least one light emitting unit is plural, and the light emitting units are arranged in interleaving to form an array.

10. The light source module as claimed in claim 8 , wherein the top surface has a plurality of top surface branches, the bottom surface has a plurality of bottom surface branches, the bottom surface branches respectively correspond to the top surface branches, and surfaces of one of the light guiding branches are formed by the corresponding top surface branch and the bottom surface branch and part of the side surfaces.

11. The light source module as claimed in claim 10 , wherein contours of orthogonal projections of the top surface and the bottom surface on a reference plane are similar to each other, and an area of the contour of the orthogonal projection of the top surface on the reference plane is smaller than an area of the contour of the orthogonal projection of the bottom surface on the reference plane.

12. The light source module as claimed in claim 10 , wherein the top surface and the bottom surface respectively have a T-shape contour.

13. The light source module as claimed in claim 10 , wherein the side surface facing the first light incident surface or each of the second light incident surfaces is the main light emitting surface of each of the light guiding branches, and the main light emitting surface of each of the light guiding branches is a trapezoid.

14. The light source module as claimed in claim 10 , wherein the bottom surface is connected with the rear optical surfaces, the first light incident surface and the second light incident surfaces to form an accommodating space.

15. The light source module as claimed in claim 10 , wherein the rear optical surfaces are perpendicular to the bottom surface.