Foldable flexible display device

1. A foldable flexible display device, comprising:

a flexible display panel, comprising a fold area;

a backplate adhered to a lower surface of the flexible display panel through an adhesive layer, and the backplate comprising a first flexible area corresponding to the fold area; and

a support plate configured to receive and support the flexible display panel and the backplate, the support plate comprising a fold portion corresponding to the fold area, the support plate divided into two sub-support plates by the fold portion, and the sub-support plates having a plurality of reinforcing structures on lower surfaces of the sub-support plates,

wherein a length of each of the reinforcing structures is ⅓ to 1/15 of a total length of the flexible display panel, a height of each of the reinforcing structures is less than or equal to 0.5 mm, and a distance between adjacent reinforcing structures is ½ to 5 times the length of each of the reinforcing structures.

2. The foldable flexible display device as claimed in claim 1 , wherein the reinforcing structures are shaped as at least one of a rectangle, a triangle, a trapezoid, and a circle.

3. The foldable flexible display device as claimed in claim 1 , wherein a material of the reinforcing structures is same as that of the support plate and is one of a metal material and a hard plastic material.

4. The foldable flexible display device as claimed in claim 3 , wherein the reinforcing structures and the sub-support plates corresponding to the reinforcing structures are formed as an integrated structure.

5. The foldable flexible display device as claimed in claim 1 , wherein the reinforcing structures are made of a cushioning material and are adhered to the lower surfaces of the sub-support plates through an adhesive layer.

6. The foldable flexible display device as claimed in claim 1 , wherein the fold portion comprises:

a hinge portion formed in an area of the support plate corresponding to the fold area;

two flexible-sliders formed in the area of the support plate corresponding to the fold area, two ends of each of the flexible-sliders connected to the hinge portion and to one of the sub-support plates, respectively, and the flexible-sliders sliding along opposite directions and rotating around the hinge portion after sliding movements.

7. The foldable flexible display device as claimed in claim 1 , further comprising:

a cover window adhered to an upper surface of the flexible display panel through an adhesive layer, the cover window covering the upper surface of the flexible display panel, and comprising a second flexible area corresponding to the fold area; and

a back cover disposed below the support plate, a gap provided between the back cover and the support plate, the back cover comprising a plug-in portion corresponding to the fold area, and the back cover divided into two parts by the plug-in portion, wherein a height of the gap is greater than a height of each of the reinforcing structures.

8. The foldable flexible display device as claimed in claim 7 , wherein the gap is filled with a cushioning material.

9. A foldable flexible display device, comprising:

a flexible display panel, comprising a fold area;

a backplate adhered to a lower surface of the flexible display panel through an adhesive layer, and the backplate comprising a first flexible area corresponding to the fold area; and

a support plate configured to receive and support the flexible display panel and the backplate, the support plate comprising a fold portion corresponding to the fold area, the support plate divided into two sub-support plates by the fold portion, and the sub-support plates having a plurality of reinforcing structures on lower surfaces of the sub-support plates, wherein a length of each of the reinforcing structures is ⅓ to 1/15 of a total length of the flexible display panel.

10. The foldable flexible display device as claimed in claim 9 , wherein the reinforcing structures are shaped as at least one of a rectangle, a triangle, a trapezoid, and a circle.

11. The foldable flexible display device as claimed in claim 9 , wherein a height of each of the reinforcing structures is less than or equal to 0.5 mm.

12. The foldable flexible display device as claimed in claim 9 , wherein a distance between adjacent reinforcing structures is ½ to 5 times the length of each of the reinforcing structures.

13. The foldable flexible display device as claimed in claim 9 , wherein a material of the reinforcing structures is same as that of the support plate and is one of a metal material and a hard plastic material.

14. The foldable flexible display device as claimed in claim 13 , wherein the reinforcing structures and the sub-support plates corresponding to the reinforcing structures are formed as an integrated structure.

15. The foldable flexible display device as claimed in claim 9 , wherein the reinforcing structures are made of a cushioning material and are adhered to the lower surfaces of the sub-support plates through an adhesive layer.

16. The foldable flexible display device as claimed in claim 9 , wherein the fold portion comprises:

a hinge portion formed in an area of the support plate corresponding to the fold area;

two flexible-sliders formed in the area of the support plate corresponding to the fold area, two ends of each of the flexible-sliders connected to the hinge portion and to one of the sub-support plates, respectively, and the flexible-sliders sliding along opposite directions and rotating around the hinge portion after sliding movements.

17. The foldable flexible display device as claimed in claim 9 , wherein a material adopted by the adhesive layer is an optically clear adhesive (OCA).

18. The foldable flexible display device as claimed in claim 9 , wherein the foldable flexible display device further comprising:

a cover window adhered to an upper surface of the flexible display panel through an adhesive layer, the cover window covering the upper surface of the flexible display panel, and comprising a second flexible area corresponding to the fold area; and

a back cover, disposed below the support plate, a gap provided between the back cover and the support plate, the back cover comprising a plug-in portion corresponding to the fold area, and the back cover divided into two parts by the plug-in portion, wherein a height of the gap is greater than a height of each of the reinforcing structures.

19. The foldable flexible display device as claimed in claim 18 , wherein the gap is filled with a cushioning material.