CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. § 119, this application claims the benefit of an earlier filing date and right of priority to International Application No. PCT/KR2021/001036, filed on Jan. 26, 2021, the contents of which are hereby incorporated by reference herein in its entirety.

FIELD

The present disclosure relates to a flexible display device including a flexible display and, more particularly, to a flexible display device characterized in that when two bodies move relative to each other, the surface area of the flexible display that is exposed to any one side thereof is changed.

BACKGROUND

With the development of flexible displays that can be bent while displaying image information thereon, research and development has been underway to provide a foldable device by applying a flexible display to a device having two bodies and a folding structure (for example, a hinge unit). In such a foldable device, since the flexible display may be disposed to completely cover the two bodies and the folding structure, a relatively large-sized display can be implemented in the device.

As another example of a device using a flexible display, rollable devices having a structure in which a display is rolled up and unrolled have been studied and developed. In such rollable devices, as the flexible display is rolled, the total size or area of the entire display can be reduced. On the contrary, as the flexible display is unrolled, the total size or area of the entire display can be increased.

As still another example of a device using a flexible display, there is a device in which as two bodies slide with respect to each other, a flexible display having a U-shape due to a curved middle portion thereof is deformed such that a surface area of the flexible display seen from any one side thereof changes.

In the device in which two bodies slide with respect to each other, if non-uniform tension is applied to the flexible display when the flexible display is deformed, the flexible display may be partially twisted or loosened.

In addition, such a device in which the two bodies slide with respect to each other may be generally kept for a relatively long time with the middle portion of the flexible display forming a U-shape. However, after the device has been kept for a relatively long time in such a state, when a user wants to deform the flexible device, the middle portion of the flexible display forming a U-shape may not be fully spread out, and a flat portion of the flexible display may not be completely curved into a U-shape. This deficiency may be because of plastic deformation occurring in a part of the flexible display, springback, and/or elasticity of the flexible display.

Accordingly, considering such characteristics of the flexible display caused by the deformation thereof, development of a flexible display device that works accurately and stably is required.

SUMMARY

An aspect of the present disclosure is directed to providing a flexible display device in which a flexible display is deformed as two bodies slide with respect to each other, the flexible display device including a means by which a predetermined tension is applied to the flexible display when a surface area of a portion of the flexible display that forms a single plane surface is increased and reduced.

Another aspect of the present disclosure is directed to providing a flexible display device in which a flexible display is deformed as two bodies slide with respect to each other, the flexible display device including a means by which a movement amount of the flexible display may be maintained constant over the entire section of the flexible display when the surface area of the portion of the flexible display that forms a single plane surface is increased and reduced.

Yet another aspect of the present disclosure is directed to providing a flexible display device in which a flexible display is deformed as two bodies slide with respect to each other, the flexible display device including a means by which tension applied to the flexible display may increase when the surface area of the portion of the flexible display that forms a single plane surface is increased, and by which the tension applied to the flexible display may decrease when the surface area of the portion of the flexible display that forms a single plane surface is reduced.

The flexible display device according to an aspect of the present disclosure may be formed to be held and carried by a user. That is, the flexible display device may be formed to have approximately the same size, the same shape, and the same weight as those of general mobile terminals.

In some embodiments, the flexible display device may include a first body, a second body, and a flexible display.

The second body may be formed to move relative to the first body in a direction parallel to a first direction. The second body may move relative to the first body in the first direction. The second body may move relative to the first body in a direction opposite to the first direction.

The first body may be formed to move relative to the second body in the direction parallel to the first direction. The first body may move relative to the second body in the direction opposite to the first direction. The first body may move relative to the second body in the first direction.

The second body may reciprocate between a first position and a second position in the direction parallel to the first direction, relative to the first body. The first position may be a relative position of the second body with respect to the first body, and the second position may also be a relative position of the second body with respect to the first body.

When the second body is in the first position relative to the first body, it can be said that the flexible display device is in a first state, and when the second body is in the second position relative to the first body, it can be said that the flexible display device is in a second state. Accordingly, in the description of the present disclosure, “the first position” may be used in the same sense as “the first state of the flexible display device,” and “the second position” may be used in the same sense as “the second state of the flexible display device.”

The direction from the first position toward the second position is the first direction.

The flexible display device may include a first edge portion and a second edge portion forming opposite edges of the flexible display device.

The first edge portion and the second edge portion may be formed to be parallel to each other, or to be substantially parallel to each other.

In one embodiment, the first edge portion may be fixed to the first body, and the second edge portion may be fixed to the second body. In another embodiment, the first edge portion may be formed integrally with the first body, and the second edge portion may be formed integrally with the second body.

In the embodiments of the present disclosure, various methods including welding, adhesion, forcible insertion, locking, interlocking, bolting, and riveting may be used for a “fixing” of elements.

When the first edge portion forms a lower side edge portion of the flexible display device, the second edge portion may form an upper side edge portion of the flexible display device.

A direction from the first edge portion to the second edge portion may be the first direction.

The first body may include a first support body.

The first support body may be formed along a second direction, which is a direction orthogonal to the first direction.

At least a portion of an outer surface of the first support body may form a curved surface. The portion of the outer surface of the first support body that forms a curved surface may support a curved portion of the flexible display.

In one embodiment of the present disclosure, the first support body may be formed integrally with the first body. In another embodiment, the first support body may be formed in the shape of a roller that can be rotated about a rotation axis extending along the second direction. That is, the first support body may be rotatably coupled to the first body.

The flexible display may include a first region and a second region.

The first region may be a region coupled to the second body. The first region may be fixedly coupled to the second body.

The first region may be fixed in front of the second body to face forward. The first region may form a front surface of the flexible display device. The first region may be formed as a plane surface. The first region may be parallel to the first direction and the second direction.

The second region may be a region extending from the first region. A portion of the second region may be curved. A portion of the second region may be curved into a semicircular shape, and as the second body moves, the position of the curved portion in the second region may be changed.

A surface area of the second region that forms a single plane surface with the first region may change as the second body moves.

When the second body moves in the first direction relative to the first body, the surface area of the second region that forms a single plane surface with the first region may increase. When the second body moves in the direction opposite to the first direction relative to the first body, the surface area of the second region that forms a single plane surface with the first region may decrease.

The second region may be curved about the first axis extending along the second direction, to form a curved surface. The second region may be curved around the first support body.

A portion of the second region may be curved about a curvature center line, which coincides with a central axis of the first support body, to form a curved surface.

The second region may include a first connected region and a second connected region.

The first connected region may be a region extending from the first region.

The second connected region may be a region extending from the first connected region.

When the second body is in the first position, the first connected region may be curved around the first support body to form a curved surface, and the second connected region may be parallel to the first region. When the second body is in the first position, the first connected region may be curved around the first support body to form a curved surface. When the second body is in the first position, the first connected region may form a curved surface of a semicircular shape about the curvature center line.

When the second body is in the second position, the first connected region may form a single plane surface with the first region, and a portion of the second connected region may be curved around the first support body, forming a curved surface. When the second body is in the second position, a portion of the second connected region may be curved around the first support body to form a curved surface. When the second body is in the second position, a portion of the second connected region may form a curved surface of a semicircular shape about the curvature center line.

According to one aspect of the present disclosure, the flexible display device may include a first rack, a second rack, a first gear, a second gear, and a driving motor.

The flexible display device may include a second support body.

The flexible display device may include a driving bracket and a driving shaft. The flexible display device may include a gear reducer.

An outer surface of the second support body may be formed to be uniform in shape along the second direction.

At least a portion of the outer surface of the second support body may form a curved surface. The portion of the outer surface of the second support body that forms a curved surface may support a curved portion of the second rack.

In one embodiment, the second support body may be formed integrally with the first body. In another embodiment, the second support body may be formed integrally with the driving bracket. In yet another embodiment, the second support body may be formed in the shape of a roller that can rotate about a rotation axis extending along the second direction. That is, the second support body may be rotatably coupled to the first body or the driving bracket.

Teeth may be repeatedly formed on the first rack along the direction parallel to the first direction. The first rack may be coupled to the second body.

Teeth may be repeatedly formed on the second rack along a direction orthogonal to the second direction. The second rack may be formed to be flexible so as to be curved about a second axis which is parallel to the first axis.

According to an aspect of the present disclosure, the second rack may form a continuous loop together with the second region. A combination of the second region and the second rack may form a continuous loop. In one embodiment, a mere combination of the second region and the second rack may form a continuous loop, and in another embodiment, a combination of the second region, the second rack, and another element(s) may form a continuous loop.

The “continuous loop” in the present disclosure may include a loop made by bending a long iron rod, string, cord, or the like and joining both ends thereof such that one end and the other end thereof are connected to each other. In addition, a closed loop and a continuous track may also be included in the “continuous loop.”

The second rack may include a first coupling portion, a second coupling portion, and a flexible portion.

The first coupling portion and the second coupling portion may respectively form both end portions of the second rack, and the flexible portion may form a middle portion of the second rack to connect the first coupling portion and the second coupling portion to each other.

For the formation of the continuous loop, the first coupling portion may be coupled to any one side of the flexible display, and the second coupling portion may be coupled to the opposite one side of the flexible display.

The first coupling portion may be fixedly connected to the flexible display at a position adjacent to an end portion of the flexible display (that is, an end portion of the second region). The first coupling portion may be directly connected to the flexible display, or alternatively, may be connected to the flexible display by medium of an element.

The first coupling portion may be coupled to an edge of the second region.

The second coupling portion may be fixedly connected to the flexible display at a position adjacent to the middle portion of the flexible display (that is, a boundary between the first region and the second region). The second coupling portion may be directly connected to the flexible display, or alternatively, may be connected to the flexible display by medium of an element.

In one embodiment, the second coupling portion may be directly coupled to the second body, and may be connected (or coupled) to the flexible display by medium of the second body.

The teeth of the second rack may be formed in the flexible portion.

The first coupling portion may extend from the flexible portion to any one side or both sides along a direction or directions parallel to the second direction.

The flexible portion may be positioned at a left side or right side of a center line of the flexible display device that bisects the flexible display device along the first direction.

The first coupling portion may be extended from the flexible portion to beyond the center line.

The first rack may be formed along the center line.

The first gear may be configured to engage with the teeth of the first rack. The first gear may be rotatably coupled to the first body or the driving bracket. The first gear may be coupled to the driving shaft and rotate with the driving shaft.

The second gear may be configured to engage with the teeth of the second rack. The second gear may be rotatably coupled to the first body or the driving bracket. The second gear may be coupled to the driving shaft and rotate with the driving shaft.

The first gear and the second gear may rotate in the same direction.

The driving motor may be configured to rotate the first gear and the second gear. The first gear and the second gear may rotate in conjunction with each other.

According to one aspect of the present disclosure, a movement distance of the first rack per rotation of the first gear in the first direction or the opposite direction of the first direction may be the same as a movement distance of the second rack per rotation of the second gear in the first direction or the opposite direction of the first direction.

According to one aspect of the present disclosure, a movement rate of the first rack in the first direction or the opposite direction of the first direction may be the same as a movement rate of the second rack in the first direction or the opposite direction of the first direction.

According to one aspect of the present disclosure, the movement distance of the second rack per rotation of the second gear in the first direction or the opposite direction of the first direction may be smaller than the movement distance of the first rack per rotation of the first gear in the first direction or the opposite direction of the first direction.

According to one aspect of the present disclosure, when a rotation speed of the first gear and a rotation speed of the second gear are the same as each other, a distance between two adjacent teeth of the first rack is d1, a distance between two adjacent teeth of the second rack is d2, the total number of teeth of the first gear is n1, and the total number of teeth of the second gear is n2, n1×d1 may be greater than n2×d2.

The teeth of the first rack may be formed on a surface of the first rack opposite to a surface of the first rack to which the second body is coupled.

The teeth of the second rack may be formed on an inner surface of the second rack.

A portion of the second rack that engages with the second gear may be parallel to the first rack.

The driving bracket may be configured to receive the first rack, the second rack, and the driving motor. The driving bracket may be fixed to the first body.

The driving bracket may include a first guide groove and a second guide groove.

The first guide groove may be formed in the shape of a concave groove at one side of the driving bracket. The first guide groove may support both edges of the first rack such that the first rack slides through the first guide groove.

The second guide groove may be formed in the shape of a concave groove at one side of the driving bracket. The second guide groove may be formed beside the first guide groove to be adjacent thereto. The second guide groove may support both edges of the second rack such that the second rack slides through the second guide groove.

The driving shaft may be formed to be parallel to the second direction and may be rotated by the driving motor. The driving shaft may be coaxially coupled to the first gear and the second gear.

The gear reducer may be received in the driving bracket, and may be configured to transfer driving force of the driving motor to the driving shaft.

The flexible display device may include a plurality of support bars.

The plurality of support bars may be formed to extend in a direction that is parallel to the second direction. The plurality of support bars may be configured to support an inner surface of the second region.

Each of the plurality of support bars may include a first support slider, a second support slider, and a connection arm.

The first support slider may form one end portion of a support bar.

The second support slider may form the other end portion of the support bar at the opposite side of the first support slider.

The connection arm may connect the first support slider to the second support slider and may support the second region.

The first body may include a first movement guide groove and a second movement guide groove.

The first movement guide groove may be formed as a U-shaped groove, and may form a path into which the first support slider is inserted and through which the first support slider moves.

The second movement guide groove may be formed as a U-shaped groove, and may form a path into which the second support slider is inserted and through which the second support slider moves.

The flexible display device may include a connection frame.

The connection frame may be fixedly coupled to the second region along an edge of the second region that is parallel to the second direction, and may serve as a medium to connect the flexible display with the second rack.

The flexible display device according to the embodiments of the present disclosure may include the first rack, the second rack, the first gear, and the second gear. The first gear and the second gear may rotate in conjunction with each other and may rotate in the same direction as each other. The second rack may form the shape of a continuous loop with the second region of the flexible display. When the flexible display is deformed as the second body moves relative to the first body, the second body and the flexible display may be moved relative to the first body by the first rack and the first gear, and the flexible display may be moved relative to the first body by the second rack and the second gear. Accordingly, when the surface area of the flexible display that forms a single plane surface increases and decreases, a predetermined tension may be applied to the entire section of the flexible display, and thus, the flexible display may be maintained in a relatively more stable state.

In the flexible display device according to an embodiment of the present disclosure, the movement distance of the first rack per rotation of the first gear in the first direction or the opposite direction of the first direction may be the same as the movement distance of the second rack per rotation of the second gear in the first direction or the opposite direction of the first direction. Accordingly, when the surface area of the flexible display that forms a single plane surface increases and decreases, the amount of movement of the flexible display may be constant over the entire section of the flexible display, and a constant tension may be maintained.

In the flexible display device according to another embodiment of the present disclosure, the movement distance of the second rack per rotation of the second gear in the first direction or the opposite direction of the first direction may be smaller than the movement distance of the first rack per rotation of the first gear in the first direction or the opposite direction of the first direction. Accordingly, when the surface area of the flexible display that forms a single plane surface increases, the tension applied to the flexible display may increase, and thus the flexible display may be prevented from being loosened. Also, when the surface area of the flexible display that forms a single plane surface decreases, the tension applied to the flexible display may decrease, and thus the load caused by the operation may be reduced.

