Flexible display panel, fabrication method, and flexible display apparatus

1. A flexible display panel, comprising:

a flexible substrate having a display area and a step area adjacent to the display area;

a display device disposed on a top surface of the flexible substrate and in the display area;

a bottom protective film disposed on a bottom surface of the flexible substrate; and

a plurality of through-holes disposed in the step area and penetrating the flexible substrate,

wherein the step area includes a plurality of through-hole sections for drilling through-holes, a plurality of lead line sections for disposing lead lines of the display device, and a bonding section for bonding the lead lines;

the step area has a first side adjacent to the display area and an opposing side far away from the display area;

the plurality of through-hole sections and the plurality of lead line sections are disposed alternately on the first side of the step area;

the bonding area is disposed on the opposing side of the step area; and

the plurality of lead line sections are connected to the bonding section.

2. The flexible display panel according to claim 1 , wherein:

a through-hole has a cross-section in a circular or a linear shape.

3. The flexible display panel according to claim 1 , wherein:

a through-hole has an opening size smaller than or equal to about 1.5 mm.

4. The flexible display panel according to claim 1 , wherein:

a through-hole section includes at least one through-hole; and

when the through-hole section includes more than one through-hole, the more than one through-hole is evenly distributed in the through-hole section.

5. The flexible display panel according to claim 1 , wherein:

a distance between a through-hole and the bonding section is greater than or equal to about 1.5 mm.

6. The flexible display panel according to claim 5 , wherein:

a distance between the through-hole and the display area is greater than or equal to about 1.5 mm.

7. The flexible display panel according to claim 1 , further including:

a sealing layer disposed on a through-hole section,

wherein the through-hole section has a bottom surface facing the flexible substrate and an opposing surface; and

the sealing layer is disposed on the opposing surface of the through-hole section.

8. The flexible display panel according to claim 1 , further including:

a flexible circuit board disposed in the bonding section and configured to electrically connect the lead lines in the bonding section.

9. The flexible display panel according to claim 1 , further including:

a thin film encapsulation layer disposed on the display device,

wherein the display device has a bottom surface facing the flexible substrate and an opposing surface; and

the thin film encapsulation layer is disposed on the opposing surface of the display device.

10. The flexible display panel according to claim 9 , further including:

a top protective film disposed on the thin film encapsulation layer,

wherein the thin film encapsulation layer has a bottom surface facing the display device and an opposing surface; and

the top protective film disposed on the opposing surface of the thin film encapsulation layer.

11. The flexible display panel according to claim 1 , wherein:

the flexible display panel is an organic light-emitting diode display panel or an electrophoretic display panel.

12. A fabrication method for a flexible display panel, comprising:

providing a flexible substrate having a display area and a step area located adjacent to the display area;

forming a display device in the display area disposed on a top surface of the flexible substrate;

forming a thin film encapsulation layer on the display device;

forming a plurality of through-holes in the step area of the flexible substrate and penetrating the flexible substrate;

attaching a bottom protective film to a bottom surface of the flexible substrate;

performing a bubble removal process to discharge air trapped in bubbles between the flexible substrate and the bottom protective film through a through-hole; and

forming the flexible display panel.

13. The fabrication method according to claim 12 , wherein:

a through-hole has a cross section in a circular or a linear shape; and

a through-hole has an opening size smaller than or equal to about 1.5 mm.

14. The fabrication method according to claim 13 , wherein:

before forming the display device in the display area disposed on the top surface of the flexible substrate, the fabrication method further includes attaching the flexible substrate to a rigid substrate in contact with the bottom surface of the flexible substrate; and

after forming the plurality of through-holes in the step area of the flexible substrate and penetrating the flexible substrate while before attaching the bottom protective film to the bottom surface of the flexible substrate, the fabrication method includes removing the rigid substrate.

15. The fabrication method according to claim 12 , wherein:

the through-hole penetrating the flexible substrate is formed by laser drilling or laser etching.

16. The fabrication method according to claim 12 , further including:

performing the bubble removal process under a pressure approximately between 4 MPa and 8 MPa, and at a temperature approximately between 40° C. and 80° C.

17. The fabrication method according to claim 12 , wherein forming the flexible display panel further including:

forming a sealing layer in the step area of the flexible substrate to seal the through-hole.

18. A flexible display apparatus, comprising a flexible display panel, wherein the flexible display panel comprises:

a flexible substrate having a display area and a step area adjacent to the display area;

a display device disposed on a top surface of the flexible substrate and in the display area;

a bottom protective film disposed on a bottom surface of the flexible substrate; and

a plurality of through-holes disposed in the step area and penetrating the flexible substrate, and

wherein the step area includes a plurality of through-hole sections for drilling through-holes, a plurality of lead line sections for disposing lead lines of the display device, and a bonding section for bonding the lead lines;

the step area has a first side adjacent to the display area and an opposing side far away from the display area;

the plurality of through-hole sections and the plurality of lead line sections are disposed alternately on the first side of the step area;

the bonding area is disposed on the opposing side of the step area; and

the plurality of lead line sections are connected to the bonding section.