Foldable electronic device

1. A foldable electronic device comprising:

a first body;

a second body;

a connection part configured to connect the first body to the second body so that the first body and the second body are rotatable to a first state in which the first and second bodies are unfolded and to a second state in which the first and second bodies overlap each other;

a flexible display element that passes over the connection part and is supported by the first and second bodies;

a roller that is rotatably installed at an end of the first body and fixed to an end of the flexible display element;

a sensor configured to detect an angular displacement of the roller; and

a controller configured to receive a detection signal from the sensor, and to determine a display area of the flexible display element in the first state or the second state,

wherein the flexible display element is located at an outer circumference of the first body, the second body, and the connection part in the second state,

wherein a part of the flexible display element is rolled around the roller in the first state,

wherein the controller is further configured to drive the determined display area of the flexible display element, and to not drive an area of the flexible display element rolled around the roller, and

wherein one end of the flexible display element including a plurality of protruding parts is fixed to a plurality of concave parts formed on a surface of the roller.

2. The foldable electronic device of claim 1 , wherein the other end of the flexible display element is fixed to the second body.

3. The foldable electronic device of claim 1 , wherein the connection part comprises:

a first shaft supported so that the first body may be rotated;

a second shaft supported so that the second body may be rotated;

a first gear centered at the first shaft; and

a second gear centered at the second shaft,

wherein the first gear and the second gear are respectively disposed in the first body and the second body so that the first gear and the second gear to interlock with each other.

4. The foldable electronic device of claim 2 , further comprising a slider attached to the flexible display element and installed to slide in the first body in a folding direction.

5. A foldable electronic device comprising:

a first body;

a second body;

a connection part configured to connect the first body to the second body so that the first body and the second body are rotatable into a first state in which the first and second bodies are unfolded and into a second state in which the first and second bodies overlap each other;

a flexible display element that passes over the connection part and is supported by the first and second bodies;

a first roller rotatably installed at an end of the first body and fixed to a first end of the flexible display element;

a second roller rotatably installed at an end of the second body and fixed to a second end of the flexible display element;

sensors configured to detect an angular displacement of the first roller and the second roller; and

a controller configured to receive a detection signal from the sensors, and to determine a display area of the flexible display element in the first state or the second state,

wherein the flexible display element is located at an outer circumference of the first body, the second body, and the connection part in the second state,

wherein a part of the flexible display element is rolled around the first roller and the second roller in the first state,

wherein the controller is further configured to drive the determined display area of the flexible display element, and to not drive areas of the flexible display element rolled around the first roller and the second roller, and

wherein both ends of the flexible display element including a plurality of protruding parts are fixed to a plurality of concave parts formed on a surface of the first roller and a plurality of concave parts formed on a surface of the second roller, respectively.

6. The foldable electronic device of claim 5 , wherein the connection part comprises:

a first shaft supported so that the first body may be rotated;

a second shaft supported so that the second body may be rotated;

a first gear centered at the first shaft; and

a second gear centered at the second shaft,

wherein the first gear and the second gear are respectively disposed in the first body and the second body so that the first gear and the second gear to interlock with each other.

7. The foldable electronic device of claim 5 , further comprising:

a first elastic member configured to apply a first elastic force to the first roller, so that parts of the flexible display element roll around the first roller; and

a second elastic member configured to apply a second elastic force to the second roller, so that parts of the flexible display element roll around the second roller.

8. The foldable electronic device of claim 5 , wherein a magnitude of the first elastic force is substantially similar to a magnitude of the second elastic force.

9. The foldable electronic device of claim 5 , further comprising a slider attached to the flexible display element and installed to slide in the first body and the second body in folding directions.

10. The foldable electronic device of claim 5 , wherein the controller is further configured to determine whether the foldable electronic device is in an unfolded state or in a folded state based on the detected angular displacement.

11. The foldable electronic device of claim 10 , wherein the controller is further configured to determine that the display area does not comprise, while the foldable electronic device is in the second state, a curved area of the flexible display element spanning between the first body and the second body.