Flexible display device

1. A flexible display device comprising:

a flexible display panel divided to have a joint section being bendable and returnable between a first display section and a second display section;

a housing accommodating the flexible display panel and supporting the second display section such that the joint section is bendable and returnable;

bending-actuators each having a first end coupled to the first display section and a second end coupled to the housing to bend or return the first display section and the joint section by axially stretching and contracting;

a back cover bending with the joint section disposed on a rear side of the flexible display panel; and

a support bar disposed on the rear side of the back cover, in parallel with the joint section, and the first end of the bending-actuators is coupled to the support bar.

2. The flexible display device of claim 1 , further comprising a touch screen panel disposed on at least one of the first display section and the second display section to perform touch sensing.

3. The flexible display device of claim 1 , wherein the back cover has a plurality slot groove recessed toward an inner side of the back cover, on the rear side of the back cover bendable with the joint section.

4. The flexible display device of claim 3 , wherein the plurality of slot grooves is provided and spaced at both sides in a direction parallel with the joint section and the plurality of slot grooves is decreased in depth from a center of the joint section to both sides of the joint section.

5. The flexible display device of claim 1 , further comprising a magnetic member disposed between a rear side of the first display section and a front side of the back cover of the flexible display panel.

6. The flexible display device of claim 5 , further comprising an adhesive member disposed between a rear side of the second display section and the front side of the back cover of the flexible display panel.

7. The flexible display device of claim 1 , wherein the bending-actuators each includes a cylinder, a piston reciprocating in the cylinder, and an elastic member elastically supported between the piston and an inside of the cylinder.

8. The flexible display device of claim 7 , wherein the support bar and the housing each have hinge members to rotatably connect ends of the piston and the cylinder.

9. A flexible display device comprising:

a flexible display panel divided into first and second display sections and a joint section, wherein the joint section is disposed between the first and second display sections and positioned between a bent state and a flat state;

a polarization film disposed on the flexible display panel;

a housing accommodating the flexible display panel and supporting the second display section to secure the bent state and the flat state;

a bending-actuator having first and second ends, wherein the first and second end are respectively attached to the first display section and the housing and pushing and pulling the first display section and the joint section to be respectively in the bent state and the flat state through linear stretching and contracting movements;

a back cover bending with the joint section disposed on a rear side of the flexible display panel; and

a support bar disposed on the rear side of the back cover, in parallel with the joint section, and the first end of the bending-actuators is coupled to the support bar.

10. The flexible display device of claim 9 , further comprising a touch screen panel disposed on at least one of the first display section and the second display section to perform touch sensing.

11. The flexible display device of claim 9 , wherein the back cover has a plurality slot groove recessed toward an inner side of the back cover, on the rear side of the back cover bendable with the joint section.

12. The flexible display device of claim 11 , wherein the plurality of slot grooves is provided and spaced at both sides in a direction parallel with the joint section and the plurality of slot grooves is decreased in depth from a center of the joint section to both sides of the joint section.

13. The flexible display device of claim 9 , further comprising a magnetic member disposed between a rear side of the first display section and a front side of the back cover of the flexible display panel.

14. The flexible display device of claim 13 , further comprising an adhesive member disposed between a rear side of the second display section and the front side of the back cover of the flexible display panel.

15. The flexible display device of claim 9 , wherein the bending-actuators each includes a cylinder, a piston reciprocating in the cylinder, and an elastic member elastically supported between the piston and an inside of the cylinder.

16. The flexible display device of claim 15 , wherein the support bar and the housing each have hinge members to rotatably connect ends of the piston and the cylinder.

17. A flexible display device comprising:

a flexible display panel divided to have a joint section being bendable and returnable between a first display section and a second display section;

a housing accommodating the flexible display panel and supporting the second display section such that the joint section is bendable and returnable;

bending-actuators each having a first end coupled to the first display section and a second end coupled to the housing to bend or return the first display section and the joint section by axially stretching and contracting; and

a back cover bending with the joint section disposed on a rear side of the flexible display panel,

wherein the back cover has a plurality slot groove recessed toward an inner side of the back cover, on the rear side of the back cover bendable with the joint section, and

wherein the plurality of slot grooves is provided and spaced at both sides in a direction parallel with the joint section and the plurality of slot grooves is decreased in depth from a center of the joint section to both sides of the joint section.