Flexible display

A flexible display is disclosed. In one aspect, the flexible display includes a window layer including a bending area and a non-bending area and a flexible display panel formed over a surface of the window layer and configured to display images. The bending area includes a plurality of cut portions which are configured to be at least partially separated along a plurality of cut lines formed therebetween.

BACKGROUND

Field

The described technology generally relates to a flexible display that is capable of preventing damage caused due to bending of the display, and maintaining the optical characteristics even when the display is bent.

Description of the Related Technology

Currently, widely known display devices, each using a unique display technology, include liquid crystal displays (LCDs), plasma display panels (PDPs), organic light-emitting diode (OLED) displays, field effect displays (FEDs), electrophoretic displays (EPDs), and the like. Techniques for forming these types of display devices with flexible material(s) are currently being researched. Since display devices formed with flexible material(s) can be used to develop new devices such as electronic books and electronic paper, these flexible displays are anticipated to be widely used for various applications.

However, since such flexible displays have a structure in which several layers are stacked, stress is not evenly distributed when the displays are bent due to the differences in the elastic coefficients of the materials forming respective layers and the differences in the properties of components contained in each layer. Since stress that is not evenly distributed is concentrated in one area, it may experience premature wear, resulting in damage or complete failure. Accordingly, flexible displays having a structure that more evenly distribute stress when bent is desired.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

One inventive aspect is a flexible display that is capable of preventing damage caused due to bending of the display, and maintaining the optical characteristics even when bent.

Further, aspects are not limited to the aforementioned aspects, and other aspects not mentioned herein will be understood by those skilled in the art from the description below.

Another aspect is a flexible display, including a window layer that includes a bent area and a non-bending area and a flexible display panel formed on one surface of the window layer to display an image, wherein the bent area can include a plurality of cut units formed by the window layer being cut into a plurality.

The flexible display can further include a hard coating layer formed on the other surface of the window layer and an adhesive layer interposed between the window layer and the hard coating layer so that one end of the cut unit slips along a surface of the adhesive layer, wherein one end of one of the plurality of cut units can be slipped along the surface of the adhesive layer to be spaced apart from an adjacent one of the plurality of the cut units.

The flexible display panel can include a display area including a pixel from which light is emitted to display an image, and a non-display area in which light is blocked not to display an image, wherein the non-bending area can be formed at a position corresponding to the display area, and the bent area can be formed at a position corresponding to the non-display area.

Another aspect is a flexible display, including a window layer that includes a bent area and a non-bending area, and a flexible display panel formed on one surface of the window layer and including an emission area where light emitted from a unit pixel passes through to display an image, wherein the bent area can be formed by partially removing the window layer.

The bent area can include a plurality of protrusions formed by partially removing the window layer to have a larger cross-section than that of the emission area at a position corresponding to the emission area, and a bent area filling portion that fills the bent area so that a height of the bent area is equal to a surface of the window layer.

The bent area filling portion can be made with transparent synthetic resins or glass.

The flexible display can further include a hard coating layer formed with the same material as the bent area filling portion, and can be formed on the other surface of the window layer.

The bent area can include a plurality of grooves formed by partially removing the window layer corresponding to the emission area to have a larger cross-section than that of the emission area while corresponding to a shape of the emission area.

The flexible display can further include a hard coating layer formed on the other surface of the window layer and formed with transparent synthetic resins or glass.

The grooves can be filled with the same material as the hard coating layer.

Another aspect is a flexible display comprising a window layer including a bending area and a non-bending area; and a flexible display panel formed over a surface of the window layer and configured to display images, wherein the bending area includes a plurality of cut portions which are configured to be at least partially separated along a plurality of cut lines formed therebetween.

In exemplary embodiments, the flexible display further comprises a hard coating layer formed over another surface of the window layer so as to oppose the flexible display panel; and an adhesive layer interposed between the window layer and the hard coating layer, wherein an end of each of the cut portions is configured to slip along a surface of the adhesive layer as the flexible display is bent. The ends of the cut portions can be further configured to slip along the surface of the adhesive layer so as to be spaced apart from each other.

In exemplary embodiments, flexible display panel can include a display area including at least one pixel configured to emit light so as to display an image; and a non-display area, wherein the non-bending area is arranged at a position corresponding to the display area, and wherein the bent area is arranged at a position corresponding to the non-display area. The cut portions can be directly connected along the surface of the flexible display panel.

Another aspect is a flexible display, comprising a window layer including a bending area and a non-bending area; and a flexible display panel formed over a surface of the window layer and including a plurality of emission areas configured to emit light to display an image, wherein at least a portion of the window layer is removed from the bent area.

In exemplary embodiments, the bent area includes a plurality of protrusions, each having a greater cross-section than that of the emission area, wherein the protrusions are arranged at positions corresponding to the emission areas; and a filler formed over the protrusions such that the height of the bending area is substantially equal to that of the window layer. The filler can comprise transparent synthetic resins or glass. The flexible display can further comprise a hard coating layer formed of the same material as the filler and formed over another surface of the window layer so as to oppose the flexible display panel.

In exemplary embodiments, the bent area includes a plurality of grooves arranged at positions corresponding to the emission areas, wherein each of the grooves has a cross-section that is greater than that of the emission areas. The flexible display can further comprise a hard coating layer formed on another surface of the window layer so as to oppose the flexible display panel, wherein the hard coating layer is formed of transparent synthetic resins or glass. A filler comprising the same material as the hard coating layer can fill in the grooves.

According to at least one embodiment, even though a flexible display is bent, since stress due to the bending can be properly dispersed, it is possible to prevent the flexible display from being damaged and to maintain the optical characteristics thereof when bent.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. However, in describing the embodiments, a description of known functions or configurations will be omitted such that the description of the subject matter is clear.

The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification. In addition, the size and thickness of each component shown in the drawings may be exaggerated for the sake of clarity and ease of description, but the described technology is not limited thereto.

FIG.1is a perspective view of a flexible display according to an exemplary embodiment.FIG.2is a drawing illustrating a configuration in which the flexible display ofFIG.1is bent.

As shownFIGS.1and2, the flexible display100according to an exemplary embodiment includes a window layer110, a flexible display panel120, and a hard coating layer130. In the flexible display100according to the present exemplary embodiment, the window layer110is formed on the outermost side of the flexible display100to block and protect the interior thereof.

Since the flexible display100can be bent, the window layer110according to the present exemplary embodiment can be formed of a flexible material to be bent together with the flexible display100. Further, the window layer110can be formed of an electrically insulating material to electrically insulate the interior of the flexible display100. The window layer110can be formed of a transparent material to allow light generated from the flexible display panel120to be emitted the exterior of the flexible display100. More specifically, the window layer110according to the present exemplary embodiment can be formed of a material such glass and/or plastic, but it is not limited thereto, and any material having such aforementioned characteristics can be used as a material for forming the window layer110of the present exemplary embodiment.

As shown inFIG.1, the window layer110can be divided into a bent area or flexible area (BD) and a non-bending area (FL). However, since the bent area (BD) and the non-bending area (FL) are shown as being divided to illustrate and explain a configuration in which the flexible display100shown inFIG.2can be bent, they may not be visually different when the flexible display100is unfolded. That is, the bent area (BD) and the non-bending area (FL) can be visually indistinguishable to a user of the flexible display100.

Further, the division between the bent area (BD) and the non-bending area (FL) is not necessarily fixed, and thus the position of the division can vary according to the region at which the flexible display100is bent.

As shown inFIG.2, the bent area (BD) is an area substantially deformed when the flexible display100is bent, and the non-bending area (FL) is an area that is not deformed and remains flat even when the flexible display100is bent. The flexible display panel120can generate light in order to display an image by the flexible display100according to the present exemplary embodiment. The flexible display panel can be formed on one surface of the window layer110according to the present exemplary embodiment.

The flexible display panel120of the present exemplary embodiment can employ any one of various display techniques, such as a liquid crystal display (LCD) panel, a plasma display panel (PDP), an organic light-emitting diode (OLED) display panel, or the like, according to the structure and light generation technique, but it is not limited thereto. In addition, the flexible display panel120of the present exemplary embodiment can be formed of a flexible material such as plastic to be easily bent.

The hard coating layer130is formed on the window layer110to protect the window layer110according to the present exemplary embodiment. Therefore, as shown inFIG.1, the flexible display panel120can be formed on the one surface of the window layer110, and the hard coating layer130can be formed on an opposing surface of the window layer110. The hard coating layer130is illustrated inFIGS.1and2, but it may be omitted in some embodiments. The hard coating layer130can also be formed of a flexible material so that the flexible display100of the present exemplary embodiment can be smoothly or easily bent and unfolded.

The bent area (BD) and the non-bending area (FL) formed on the window layer110can be formed to have a discontinuous structure. The term “discontinuous structure” generally means that the arrangement or configuration of the bent and non-bending areas (BD) and (FL) are different from each other. Therefore, the bent area (BD) and the non-bending area (FL) can be different from each other in their arrangement and/or configuration, and they can vary according to the position at which the flexible display100is bent, as described above.

A detailed structural difference between the bent area (BD) and the non-bending area (FL) according to first to third exemplary embodiments will be described in detail with reference toFIGS.3to8.FIG.3is a partial cross-sectional view of a flexible display100according to a first exemplary embodiment taken along line II-II ofFIG.1.FIG.4is a drawing illustrating a configuration in which the flexible display100ofFIG.3is bent.FIG.5is a partial cross-sectional view of a flexible display100according to a second exemplary embodiment taken along line II-II ofFIG.1.FIG.6is a drawing illustrating a configuration of the flexible display100ofFIG.5.FIG.7is a partial cross-sectional view of a flexible display100according to a third exemplary embodiment taken along line II-II ofFIG.1.FIG.8is a drawing illustrating a configuration of the flexible display100ofFIG.7.

The first exemplary embodiment will now be described in detail with reference toFIGS.3and4. As shown inFIGS.3and4, the flexible display100according to the first exemplary embodiment includes a plurality of cut units or cut portions112formed by some or all of the window layer110corresponding to the bent area (BD) being cut. The cut units112are formed by some or all of the window layer110being cut so that when the flexible display100is bent, the cut units112are arranged to be spaced apart from each other so that stress generated due to the flexible display100being bent can be distributed. Further, when the flexible display100is unfolded, the cut units112are arranged to be adjacent to each other.

Since the window layer110can be divided into two areas for each cut made in the window layer110, there are a plurality of cut units112. A laser cutter can be used for cutting the window layer110to form the cut units112, but is not limited thereto, and any cutter that can precisely cut some or the all of the window layer110for forming a cut line or a slit in the window layer110can be used. The cut units112formed by cutting the window layer110according the present exemplary embodiment can be cut to be parallel to each other in a direction perpendicular to a surface of the window layer110to have a predetermined width along a thickness direction of the window layer110. However, the present exemplary embodiment is not limited thereto, that is, the scope for implementing the described technology is not limited to a cut structure for easily bending the flexible display100.

The flexible display100according to the present exemplary embodiment described above can include a hard coating layer130, and can further include an adhesive layer140. The hard coating layer130is formed on the a surface of the window layer110, and the adhesive layer140is interposed between the window layer110and the hard coating layer130, and one end portion of the cut units112can slip along a surface of the adhesive layer140.

When the flexible display100is bent as shown inFIG.4, the cut unit112is spaced apart from the adjacent cut unit112while one end portion of the cut unit112slips along the surface of the adhesive layer140. Accordingly, when the flexible display100is bent, as shown inFIG.4, a plurality of cut units112can be arranged in an arc shape. Additionally, the other end portions of the cut units112according to the present exemplary embodiment can be fixed to the flexible display panel120. The other end portions of the cut units112fixed to the flexible display panel120maintain the original spacing between the adjacent cut units112even when the flexible display100is bent. Accordingly, refraction or dispersion of light emitted from the flexible display panel120can be reduced or prevented.

Further, the flexible display panel120includes a plurality of pixels that can emit light, a display area (not shown) in which light emitted from the pixels is emitted to the exterior of the flexible display100to display an image, and a non-display area (not shown) in which light is blocked in order to not display an image. Accordingly, the non-bending area (FL) of the present exemplary embodiment can be formed at a position corresponding to the display area, and the bent area (BD) can be formed at a position corresponding to the non-display area. When the bent area (BD) is formed at the position corresponding to the display area, light emitted from the display area can be refracted or dispersed due to the arrangement of the cut units112in certain configurations. Further, if the bent area (BD) is arranged at the position corresponding to the display area, problems such as light leakage may occur.

Accordingly, the bent area (BD) according to the present exemplary embodiment can be formed at the position corresponding to the non-display area (NE) to solve the aforementioned problem. Accordingly, the cut units112according to the present exemplary embodiment can also be formed at a position where an emission area (LE) does not exist (e.g., the non-display area), and thus the non-bending area (FL) can be formed at the position corresponding to the display area. Therefore, a flexible display100capable of displaying an image more stably is provided.

The second and third exemplary embodiments will now be described in detail with reference toFIGS.5to8.FIGS.5and6illustrate a flexible display100in which a plurality of protrusions114are formed in a bent area (BD) according to the second exemplary embodiment.FIGS.7and8illustrate a flexible display100in which a plurality of grooves116are formed in a bent area (BD) according to the third exemplary embodiment.

As shown inFIGS.5and6, the flexible display100in which the protrusions114are formed includes a window layer110and a flexible display panel120including the bent area (BD) and a non-bending area (FL). Since the window layer110and the flexible display panel120of the present exemplary embodiment correspond to those described above, a detailed description of such will be omitted. In the embodiment ofFIGS.5and6, the flexible display panel120can include an emission area (LE) through which light emitted from a unit pixel passes. In other words, the flexible display panel120includes the emission area (LE) in which an area of the flexible display panel120corresponding to the unit pixel is formed.

The bent area (BD) of the present exemplary embodiment is formed by partially removing the window layer110. More specifically, as shown inFIGS.5and6, the bent area (BD) is formed by removing an area of the window layer110, other than an area of the window layer110corresponding to the protrusions114, so that the protrusions114having a greater cross-section than that of the emission area (LE) of the flexible display panel120can be formed. For example, as shown inFIGS.5and6, the width W1of the protrusions can be greater than the width W2of the emission areas (LE). In other words, the bent area (BD) of the present exemplary embodiment is formed by removing the window layer110so that the protrusions114remain after the removal.

As in the present exemplary embodiment, when the cross-section of the protrusion114is greater than that of the emission area (LE), light emitted from the emission area (LE) can be directly emitted without being refracted or dispersed. Accordingly, even when the flexible display100is bent, the optical characteristics thereof can be prevented from deteriorating. The protrusions114of the present exemplary embodiment can be formed to have substantially the same height as the thickness of the window layer110, but they is not limited thereto, and the protrusions114can be formed to have height that is less than the thickness of the window layer110. In addition, the bent area (BD) can be formed to have a shape as shown inFIGS.5and6by leaving a portion of the window layer110after removing some of the window layer110so that a lower portion of the protrusions114can be connected to the window layer110.

A bent area filling portion or filler132is formed on a surface of the removed window layer110. The bent area filling portion132is formed by filling the bent area (BD) so that the removed area of the window layer110may have substantially the same height and width as the surface of the window layer110. The bent area filling portion132may completely cover the protrusions114, but is not limited thereto, and when the protrusions114is formed to have substantially the same height as the surface of the window layer110, a surface of the protrusions114can be exposed to the exterior of the surface of the bent area filling portion132even after the bent area (BD) is filled by the bent area filling portion132.

Further, the flexible display panel120according to the present exemplary embodiment can include a hard coating layer130formed on the window layer110and the bent area filling portion132. In the embodiment ofFIGS.5and6, the hard coating layer130can be formed of the same material as the bent area filling portion132. As described above, the material forming the hard coating layer130can be flexible. Accordingly, the bent area filling portion132of the present exemplary embodiment can also be formed of the same material as the hard coating layer130.

Since the bent area filling portion132is formed on an upper portion of the flexible display panel120corresponding to the emission area (LE), it can be formed of a transparent material including transparent synthetic resins or glass. Accordingly, the hard coating layer130of the present exemplary embodiment can also be formed of a transparent material.

As shown inFIGS.7and8, a flexible display100in which the window layer110is partially removed so that a plurality of grooves116can be formed according to the third exemplary embodiment also includes a window layer110and a flexible display panel120including a bent area (BD) and a non-bending area (FL). Since the window layer110and the flexible display panel120of the present exemplary embodiment correspond to those described above, a detailed description therefor will be omitted.

In the embodiment ofFIGS.7and8, the bent area (BD) includes a plurality of grooves116formed by partially removing the window layer110. The grooves116are formed by partially removing the window layer110to have a greater cross-section than that of the emission area (LE) of the flexible display panel120. For example, as shown inFIGS.7and8, the width W1of the grooves116can be greater than the width W2of the emission areas (LE). When the cross-section of the grooves116are greater than that of the emission area (LE), as in the present exemplary embodiment, light emitted from the emission area (LE) can be directly emitted to the exterior of the flexible display100without being refracted or dispersed, as in the second exemplary embodiment. Accordingly, even when the flexible display100is bent, its optical characteristics can be preserved.

The grooves116of the present exemplary embodiment are formed removing a portion of the window layer110formed at a position corresponding to the emission area (LE), but they are not limited thereto, and the grooves116can be formed by partially removing the window layer110in a thickness direction of the window layer110. The flexible display100of the present exemplary embodiment can further include a hard coating layer130formed on the other surface of the window layer110. Since the hard coating layer130of the present exemplary embodiment is formed on an upper portion of emission area (LE) of the flexible display panel120, as in the hard coating layer130of the second exemplary embodiment, it can be formed of a transparent material including transparent synthetic resins or glass. The grooves116according to the present exemplary embodiment can be filled with the same material as the hard coating layer130, so that the groove116becomes a filled groove134.

When the filled grooves134are filled with the same material as the hard coating layer130, since refraction or dispersion of light emitted from the emission area (LE) can be prevented by an interface surface between the filled grooves134and the hard coating layer130, the optical characteristics of the flexible display100of the present exemplary embodiment can be maintained.

A flexible display100according to various exemplary embodiments has been described. According to the various exemplary embodiments, even when the flexible display100is bent, since stress due to the bending can be properly distributed, it is possible to prevent the flexible display from being damaged and maintain the optical characteristics thereof when being bent.