Flexible display substrate, manufacturing method thereof, and flexible display device

1. A flexible display substrate, comprising:

an elastic substrate;

a base film provided at one side of the elastic substrate, the base film being provided with a plurality of fracture structures; and

a display substrate provided at a surface of the base film facing away from the elastic substrate, wherein

an orthographic projection of the display structure on the elastic substrate has no overlap area with an orthographic projection of the fracture structure on the elastic substrate, wherein

the fracture structure has a fracture position, the fracture position is located at one side of the base film facing away from the elastic substrate,

the plurality of fracture structures are arranged in an array and comprise multiple first fracture structures and multiple second fracture structures;

the multiple first fracture structures are arranged alternately with the multiple second fracture structures;

an extending direction of a length of the first fracture structure is perpendicular to an extending direction of a length of the second fracture structure; and

orthographic projections of the first fracture structure and the second fracture structure on the elastic substrate both have a strip shape.

2. The flexible display substrate according to claim 1 , wherein the plurality of fracture structures define a plurality of display unit regions;

the display structure comprises:

a plurality of thin film transistors (TFTs) correspondingly provided in the plurality of display unit regions;

a plurality of signal lines arranged to bypass the plurality of fracture structures;

a plurality of light-emitting elements provided at one side of the plurality of TFTs facing away from the elastic substrate and correspondingly provided in the plurality of display unit regions; and

a plurality of encapsulation structures provided at one side of the plurality of light-emitting elements facing away from the elastic substrate, each of the plurality of encapsulation structures is configured to encapsulate at least one light-emitting element, and an orthographic projection of the encapsulation structure on the elastic substrate has no overlap area with the orthographic projection of the fracture structure on the elastic substrate.

3. The flexible display substrate according to claim 1 , wherein a material of the base film is polyimide.

4. A flexible display device, comprising the flexible display substrate according to claim 1 .

5. The flexible display device according to claim 4 , wherein the plurality of fracture structures define a plurality of display unit regions;

the display structure comprises:

a plurality of thin film transistors (TFTs) correspondingly provided in the plurality of display unit regions;

a plurality of signal lines arranged to bypass the plurality of fracture structures;

a plurality of light-emitting elements provided at one side of the plurality of TFTs facing away from the elastic substrate and correspondingly provided in the plurality of display unit regions; and

a plurality of encapsulation structures provided at one side of the plurality of light-emitting elements facing away from the elastic substrate, each of the plurality of encapsulation structures is configured to encapsulate at least one light-emitting element, and an orthographic projection of the encapsulation structure on the elastic substrate has no overlap area with the orthographic projection of the fracture structure on the elastic substrate.

6. The flexible display device according to claim 4 , wherein a material of the base film is polyimide.

7. A manufacturing method of a flexible display substrate, comprising:

forming a plurality of protrusions on a base substrate;

forming a base film at one side of the plurality of protrusions facing away from the base substrate, so that a plurality of concaves is formed by the plurality of protrusions at one side of the base film facing to the base substrate;

forming a display structure at a surface of the base film facing away from the base substrate;

peeling off the base film along with the display structure from the base substrate, and remaining the plurality of protrusions on the base substrate; and

attaching the surface of the base film facing away from the display structure onto an elastic substrate and stretching the elastic substrate so that the base film is fractured at positions of the plurality of concaves,

wherein the plurality of protrusions are arranged in an array and comprise multiple first protrusions and multiple second protrusions;

the multiple first fracture protrusions are arranged alternately with the multiple second protrusions;

an extending direction of a length of the first protrusion is perpendicular to an extending direction of a length of the second protrusion; and

the first fracture protrusion and the second protrusion both have a strip structure.

8. The manufacturing method of the flexible display substrate according to claim 7 , wherein forming the plurality of protrusions on the base substrate comprises:

forming a pattern of plurality of protrusions on the base substrate by using a glass cement;

finalizing a shape of the pattern of plurality of protrusions; and

solidifying the glass cement to obtain the plurality of protrusions.

9. The manufacturing method of the flexible display substrate according to claim 8 , wherein forming the plurality of protrusions on the base substrate comprises:

coating a patterned glass cement on the base substrate by a screen printing process to obtain the pattern of plurality of protrusions;

baking the pattern of plurality of protrusions to thermally solidify the pattern of plurality of protrusions so as to finalize a shape of the pattern of plurality of protrusions; and

solidifying the glass cement by a laser scanning process to obtain the plurality of protrusions.

10. The manufacturing method of the flexible display substrate according to claim 7 , wherein a thickness of the base film is greater than a height of the protrusion.

11. The manufacturing method of the flexible display substrate according to claim 7 , wherein forming the display structure at the surface of the base film facing away from the base substrate comprises:

forming a plurality of thin film transistors (TFTs) and a plurality of signal lines on the surface of the base film facing away from the base substrate, so that positions of the plurality of TFTs correspond to areas between the plurality of concaves and that the plurality of signal lines are arranged to bypass the plurality of concaves;

forming a plurality of light-emitting elements at one side of the plurality of TFTs facing away from the base substrate; and

forming a plurality of encapsulation structures at one side of the plurality of light-emitting elements facing away from the base substrate so that each of the plurality of encapsulation structures encapsulates at least one light-emitting element therein and that an orthographic projection of the encapsulation structure on the base film has no overlap area with an orthographic projection of the concave on the base film.

12. The manufacturing method of the flexible display substrate according to claim 7 , wherein after forming the plurality of protrusions and before forming the base film, the manufacturing method further comprises:

forming a debonding layer at the side of the plurality of protrusions facing away from the base substrate.

13. The manufacturing method of the flexible display substrate according to claim 12 , wherein a material of the debonding layer is silicon nitride.