Field of Technology
The present disclosure relates to a display device, and more particularly, to a foldable display device.
Discussion of the Related Art
As information technology and mobile communication technology have been developed, a display device capable of displaying a visual image has also been developed. Flat panel display devices have been developed. For example, flat panel display devices include a liquid crystal display (LCD) device, a plasma display panel (PDP) device, a field emission display (FED) device, and an organic light emitting display (OLED) device. A flat panel display device is used instead of a cathode ray tube (CRT) because of excellent characteristics, such as thin profile, low weight, low power consumption, and the like.
Generally, a glass substrate, which is desired for high temperature fabrication processes, is used for the flat panel display device. Accordingly, there are limitations with respect to achieving a thin profile, low weight, and/or flexibility.
To overcome the limitation of the glass substrate, a flexible substrate, e.g., a plastic substrate, is used to provide a flexible display device. The flexible display device may be classified into an unbreakable display device, a bendable display device, a rollable display device and a foldable display device. Recently, among these flexible display devices, the foldable display device, which can be folded and unfolded, has been widely researched. The foldable display device is portable in a folded state, and an image is displayed in an unfolded state. The foldable display device can be used for a mobile apparatus, such as a mobile phone, an ultra mobile PC, an e-book and an e-paper, a TV, or a monitor.
The foldable display device may include a display panel, a backplate and a cover window. The backplate is disposed under the display panel to support the display panel, and the cover window is disposed over the display panel to protect the display panel.
On the other hand, because the foldable display device should be folded and unfolded, all of the display panel, the backplate, and the cover window should be of a very thin film type. However, an external impact is transmitted in a vertical direction in the thin film type elements. Namely, an impact, which is applied to the cover window or the backplate, is directly transmitted into the display panel. As a result, the display panel may be damaged, and the display quality of the foldable display device is decreased.