Foldable display

A foldable display is disclosed. In one aspect, the foldable display includes a display panel including: a plurality of flat regions and a folding region interposed between the flat regions. Each of the flat regions includes a fixed region and a semi-fixed region interposed between the fixed region and the folding region. The foldable display also includes a plurality of substrates respectively attached to the flat regions and a plurality of fixed adhesive members respectively interposed between the fixed regions and the substrates. The fixed adhesive members respectively attach the substrates to the fixed regions. The foldable display further includes a plurality of semi-fixed adhesive members respectively interposed between the semi-fixed regions and the substrates. The semi-fixed adhesive members are configured to respectively attach/detach the semi-fixed adhesive regions to/from the substrates based on the degree to which the display panel is folded.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application claims priority under 35 U.S.C. §119 of Korean Patent Application No. 10-2015-0008752, filed on Jan. 19, 2015, the entire contents of which are hereby incorporated by reference.

BACKGROUND

Field

The present disclosure generally relates to a display device, and more particularly, to a foldable or flexible display device.

Description of the Related Technology

Electronic devices that display images, such as smart phones, digital cameras, notebook computers, navigation units, and televisions, include display panels for displaying images.

Thin and lightweight flat display panels are widely used for image display. Many types of flat display panels exist, including liquid crystal display (LCD) panels, organic light-emitting diode (OLED) display panels, plasma display panels (PDPs), electrophoretic display (EPD) panels, and the like.

Additionally, foldable displays, which can be folded for portability and unfolded to increase the viewing area, are being developed.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

One inventive aspect is a foldable display having an improved reliability and durability.

Another aspect is a foldable display including: a display panel including a plurality of non-folding regions and a folding region interposed between the non-folding regions, the non-folding regions each including a fixed region and a semi-fixed region defined between the fixed region and the folding region; a plurality of substrates correspondingly provided to the non-folding regions, respectively; a fixed adhesive member interposed between the fixed region and the substrates, and attaching the substrates to the fixed region; and a semi-fixed adhesive member interposed between the semi-fixed region and the substrates, and attaches/detaches the semi-fixed region to/from the substrates according to a folded degree of the display panel.

In some embodiments, when the display panel is not folded, the semi-fixed adhesive member can attach the semi-fixed region to the substrates, and when the display panel is folded, at least a portion of the semi-fixed region can be detached from the substrates.

In other embodiments, when the display panel is folded, the semi-fixed adhesive member can maintain a configuration of being attached to the substrate and can be detached from the semi-fixed region.

In still other embodiments, when the display panel is folded, the semi-fixed adhesive member can maintain a configuration of being attached to the semi-fixed region and can be detached from the substrate.

In even other embodiments, when the display panel is folded, outer surfaces of the non-folded regions can face each other.

In yet other embodiments, at least a portion of the semi-fixed adhesive member can be detached from the substrates when a folding angle defined by upper surfaces of the substrates is less than an attachment angle.

In further embodiments, when the folding angle is less than the attachment angle, stress applied to the display panel can be greater than a stress limit which generates a crack to the display panel.

In still further embodiments, the fixed adhesive member can have first adhesive force, and the semi-fixed adhesive member can have second adhesive force less than the first adhesive force.

In even further embodiments, the first adhesive force can be about 2,000 to about 5,000 gf/mm, and the second adhesive force can be about 500 to about 1,000 gf/mm.

In yet further embodiments, the fixed adhesive member can comprise an acryl-based adhesive material, and the semi-fixed adhesive member can comprise a silicon-based adhesive material.

Another aspect is a foldable display includes a display panel including a plurality of non-folding regions and a folding region interposed between the non-folding regions, the non-folding regions each including a fixed region and a semi-fixed region defined between the fixed region and the folding region, and having a first flexibility; a plurality of substrates correspondingly provided to the non-folding regions, receptively; a fixed adhesive member interposed between the fixed region and the substrates, and attaches the substrates to the fixed regions; a stress relief part interposed between the semi-fixed region and the plurality of substrates, and having a second flexibility less than the first flexibility; and an auxiliary adhesive members including an upper auxiliary adhesive member interposed between the stress relief part and the semi-fixed region, and attaches the stress relief part to the semi-fixed region and a lower auxiliary adhesive member interposed between the stress relief part and the substrates, and attaches the stress relief part to the substrates.

In some embodiments, the substrates can include a groove recessed toward the lower surface of the substrate to correspond to the semi-fixed region, and the stress relief part can be arranged in the groove.

In other embodiments, a first distance from the lower surface of the substrates opposite the display panel to a lower surface of the fixed region can be substantially equal to a distance from the lower surface of the substrates to a lower surface of the semi-fixed region.

Another aspect is a foldable display comprising a display panel, comprising: a plurality of flat regions, and a folding region interposed between the flat regions, wherein each of the flat regions comprises: a fixed region, and a semi-fixed region interposed between the fixed region and the folding region; a plurality of substrates respectively attached to the flat regions; a plurality of fixed adhesive members respectively interposed between the fixed regions and the substrates, wherein the fixed adhesive members respectively attach the substrates to the fixed regions; and a plurality of semi-fixed adhesive members respectively interposed between the semi-fixed regions and the substrates, wherein the semi-fixed adhesive members are configured to respectively attach/detach the semi-fixed adhesive regions to/from the substrates based on the degree to which the display panel is folded.

In exemplary embodiments, when the display panel is in an unfolded configuration, the semi-fixed regions are respectively attached to the substrates by means of the semi-fixed adhesive members, and when the display panel is in a folded configuration, at least a portion of each of the semi-fixed regions is respectively detached from the corresponding substrate.

In exemplary embodiments, when the display panel is in the folded configuration, each of the semi-fixed adhesive members is attached to the corresponding substrate and is detached from the corresponding semi-fixed region.

In exemplary embodiments, when the display panel is in the folded configuration, each of the semi-fixed adhesive members is attached to the corresponding semi-fixed region and is detached from the corresponding substrate.

In exemplary embodiments, when the display panel is in the folded configuration, outer surfaces of the flat regions face each other.

In exemplary embodiments, at least a portion of each of the semi-fixed adhesive members is detached from the corresponding substrate when a folding angle defined by the substrates is less than an attachment angle.

In exemplary embodiments, when the folding angle is less than the attachment angle, a stress applied to the display panel is greater than a stress limit at which a crack is formed in the display panel.

In exemplary embodiments, each of the fixed adhesive member has a first adhesive force, and wherein each of the semi-fixed adhesive members has a second adhesive force that is less than the first adhesive force.

In exemplary embodiments, the first adhesive force is between about 2,000 to about 5,000 gf/mm, and wherein the second adhesive force is between about 500 to about 1,000 gf/mm.

In exemplary embodiments, each of the fixed adhesive members is formed of an acryl-based adhesive material, and wherein each of the semi-fixed adhesive members is formed of a silicon-based adhesive material.

Another aspect is a foldable display, comprising a display panel, comprising: a plurality of flat regions, and a folding region interposed between the flat regions, wherein the display panel has a first flexibility, and wherein each of the flat regions comprises: a fixed region, and a semi-fixed region interposed between the fixed region and the folding region; a plurality of substrates respectively attached to the flat regions; a plurality of fixed adhesive members respectively interposed between the fixed regions and the substrates, wherein the fixed adhesive members respectively attach the substrates to the fixed regions; a plurality of stress relief portions respectively interposed between the semi-fixed regions and the substrates, wherein each of the stress relief regions has a second flexibility that is less than the first flexibility; and a plurality of auxiliary adhesive members, each comprising: an upper auxiliary adhesive member interposed between the corresponding stress relief portions and the corresponding semi-fixed region, wherein the upper auxiliary adhesive member attach the corresponding stress relief portion to the corresponding semi-fixed region; and a lower auxiliary adhesive member interpose between the corresponding stress relief portions and the corresponding substrate, wherein the lower auxiliary adhesive member attaches the corresponding stress relief portion to the corresponding substrate.

In exemplary embodiments, each of the substrates comprises a groove recessed toward a lower surface of the substrate to correspond to the corresponding semi-fixed region, and wherein the stress relief portion is arranged in the groove.

In exemplary embodiments, a first distance from the lower surface of each of the substrate opposite the display panel to a lower surface of the corresponding fixed region is substantially equal to a distance from a lower surface of each of the substrates to a lower surface of the corresponding semi-fixed region.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

The described technology can be modified in several different forms, and specific embodiments will be exemplified in the drawings and described in detail. It is to be understood that the described technology is not limited to the disclosed embodiments, and is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the disclosure, including the appended claims.

Like reference numerals refer to like elements throughout. In the drawings, the dimensions and sizes of each structure may be exaggerated, omitted, or schematically illustrated for the sake of clarity. It will be understood that although the terms “first” and “second” may be used herein to describe various elements, these elements should not be limited by these terms. Terms are only used to distinguish one component from other components. For example, an element referred to as a first element in one embodiment can be referred to as a second element in another embodiment. Terms in the singular form may include the plural form unless otherwise intended.

In the specification, the meanings of the terms ‘include’ and/or ‘comprise’ specifies the inclusion of the referenced property, numeral, step, operation, element or a combination thereof, but does not exclude other properties, numerals, steps, operations, elements or combinations thereof. In addition, it will be understood that when a layer, a film, a region, or a plate is referred to as being ‘on’ another layer, film, region, or plate, it can be directly on the other layer, film, region, or plate, or intervening layers, films, regions, or plates may also be present. On the contrary, it will be understood that when a layer, a film, a region, or a plate is referred to as being ‘under’ another layer, film, region, or plate, it can be directly under the other layer, film, region, or plate, or intervening layers, films, regions, or plates may also be present. Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings.

FIG. 1is a cross-sectional view of a display apparatus or foldable display according to an embodiment.FIG. 2is an enlarged cross-sectional view of region A ofFIG. 1.

Referring toFIGS. 1 and 2, the display apparatus1000includes a substrate100and a display panel200formed on the substrate100.

The display panel200can display image(s). The display panel200can include an organic light-emitting diode (OLED) display panel, a liquid crystal display (LCD) panel, a plasma display panel (PDP), an electrophoretic display (EPD) panel, or the like.

The display panel200includes a lower plate201and an upper plate202facing the lower plate201. A light control layer203is interposed between the upper plate202and the lower plate201. The lower plate201and the upper plate202have one or more electrodes. The display panel200adjusts an electric field applied to the light control layer203through the electrodes to display an image.

The entire or at least a portion of the display panel200is flexible. In the current embodiment, the components constituting the display panel200are formed of flexible materials. For example, the lower plate201and the upper plate202can be formed of a material such as plastic. When an external force is applied to the display panel200, the display panel200can be folded due to the external force.

Here, the meaning of the term “folding” is to be transformable from an original shape into another shape, and includes being wound like a roll as well as being bent along one or more lines.

The display panel200can include a plurality of non-folding regions or flat regions and a folding region230.

In an embodiment, the non-folding regions include a first non-folding region or first flat region210and a second non-folding region or second flat region220. The folding region230is interposed between the first and second non-folding regions210and220. That is, the first non-folding region210, the folding region230, and the second non-folding region220can be sequentially defined along a first direction D1.

The substrate100, for example, includes first and second substrates110and120which are formed of a rigid material such as glass. The first substrate110is arranged in an area corresponding to the first non-folding region210. The first substrate110supports the first non-folding region210so that the first non-folding region210cannot be folded by external force.

The second substrate120is arranged in an area to correspond to the second non-folding region220. The second substrate120can be arranged apart from the first substrate110in the first direction D1by about the width of the folding region230along the direction D1. The second substrate120supports the second non-folding region220so that the second non-folding region220cannot be folded by external force.

The first non-folding region210includes a first fixed region211and a first semi-fixed region212. The first semi-fixed region212is a region adjacent to the folding region230. More specifically, the first semi-fixed region212can be defined between the folding region230and the first fixed region211. That is, the first fixed region211, the first semi-fixed region212, and the folding region230can be sequentially defined along a first direction D1.

The second non-folding region220includes a second fixed region221and a second semi-fixed region222. The second semi-fixed region222is a region adjacent to the folding region230. More specifically, the second semi-fixed region222can be defined between the folding region230and the second fixed region221. That is, the second fixed region221, the second semi-fixed region222, and the folding region230can be sequentially defined along a second direction D2opposite the first direction D1.

The display apparatus1000further includes a fixed adhesive member and a semi-fixed adhesive member, which are interposed between the display panel200and the substrate100. The fixed adhesive member includes first and second fixed adhesive members310and320, and the semi-fixed adhesive member includes first and second semi-fixed adhesive members410and420.

The first and second fixed adhesive members310and320have adhesiveness. More specifically, the first and second fixed adhesive members310and320have a first adhesive force. The first adhesive force can be, for example, about 2,000 to about 5,000 gf/mm. Also, in an embodiment, the first and the second fixed adhesive members310and320may include an acryl-based adhesive material.

The first fixed adhesive member310is interposed between the first fixed region211and the first substrate110. The first fixed adhesive member310attaches a lower surface of the first fixed region211to an upper surface of the first substrate110. Accordingly, the first fixed region211is fixed to the first substrate110and is not detached from the first substrate110, even when the display apparatus1000is folded.

The second fixed adhesive member320is interposed between the second fixed region221and the second substrate120. The second fixed adhesive member320attaches a lower surface of the second fixed region221to an upper surface of the second substrate120. Accordingly, the second fixed region221is fixed to the second substrate120, and is not detached from the second substrate120, even when the display apparatus1000is folded.

The first and second semi-fixed adhesive members410and420have adhesiveness. More specifically, the first and second semi-fixed adhesive members410and420have a second adhesive force.

The second adhesive force is less than the first adhesive force. The second adhesive force may be determined such that when the display apparatus1000is folded, a stress greater than a stress limit of the display panel200is not applied to the first and second semi-fixed regions212and212. This will be described below with reference toFIGS. 4 and 5.

In an embodiment, the second adhesive force can be between about 500 to about 1,000 gf/mm. Also, for example, the first and the second semi-fixed adhesive members410and420can include a silicon-based adhesive material.

The first semi-fixed adhesive member410is interposed between the first semi-fixed region212and the first substrate110. The first semi-fixed adhesive member410attaches a lower surface of the first semi-fixed region212to an upper surface of the first substrate110.

Here, the term “semi-fixed” refers to the ability to transition between being fixed or not fixed on the basis of an external force. In other words, when the display apparatus1000is not folded and remains unfolded, no external force is applied to the first semi-fixed region212. Thus, when external force is not applied to the first semi-fixed region212, the first semi-fixed region212is attached and fixed to the first substrate110by means of the first semi-fixed adhesive member410.

On the other hand, when the display apparatus1000is folded, external force, which acts in a direction which separates the first semi-fixed region212and the first substrate110, is applied to the first semi-fixed region212. When external force is applied to the first semi-fixed region212, the first semi-fixed region212can be detached from the first substrate110. Also, when the external force is not applied again, at least a portion of the first semi-fixed region212can be attached and fixed to the first substrate110again by means of the first semi-fixed adhesive member410.

The second semi-fixed adhesive member420is interposed between the second semi-fixed region222and the second substrate120. The second semi-fixed adhesive member420allows a lower surface of the second semi-fixed region222to be semi-fixed to an upper surface of the second substrate120.

A first thickness Th1of the first and second fixed adhesive members310and320can be substantially the same as a second thickness Th2of the first and second semi-fixed adhesive members410and420.

Accordingly, the generation of a bent portion or a concavo-convex portion in the display panel200along a border of the first fixed adhesive member310and the first semi-fixed adhesive member410can be prevented.

FIG. 3is a cross-sectional view illustrating a folded configuration of the display apparatus shown inFIG. 1.FIG. 4is an enlarged cross-sectional view of region B ofFIG. 3.

Referring toFIGS. 3 and 4, the display apparatus1000can be folded such that a first outer surface2111of the first fixed region211and a second outer surface2211of the second fixed region221face each other. In this configuration, since the first and second non-folded region210and220are respectively fixed to the first and second substrate110and120which are rigid, they are not folded. On the other hand, the folding region230is folded because it is not fixed to the first or second substrate110or120.

In general, when an object is folded, stresses are concentrated at a middle region between the folded region and non-folded region of the object. As a result, the middle region may be the most damaged due to folding. That is, when the display apparatus1000according to an embodiment is folded, stresses may be concentrated at the first and second semi-fixed regions212and222.

However, the display apparatus1000according to an embodiment can relieve the stresses concentrated at the first and second semi-fixed regions212and222.

More specifically, since the first and second semi-fixed regions212and222are semi-fixed to the first and second substrate110and120by means of the first and second semi-fixed adhesive members410and420, damage to the first and second semi-fixed regions212and222can be prevented when the display apparatus1000is folded.

More specifically, the first and second semi-fixed adhesive members410and420attach/detach the first and second semi-fixed regions212and222to/from the first and second substrates110and120according to the folded degree of the display panel200.

As illustrated inFIGS. 3 and 4, when the display apparatus1000is folded, external force EF is generated in the first and second semi-fixed regions212and222, and the external force EF acts as a stress on the first and second semi-fixed regions212and222. By means of the external force EF, at least a portion of the semi-fixed adhesive members410and420is respectively detached from upper surfaces of the first and second substrates110and120, and a gap G is defined between the first and second semi-fixed adhesive members410and420and the first and second substrates110and120. As a result, stresses generated in the first and second semi-fixed regions212and222can be reduced.

The adhesive force between the first and second semi-fixed members410and420and the first and second substrates110and120can be weaker than the adhesive force between the first and second semi-fixed adhesive members410and420and the first and second semi-fixed regions212and222. Accordingly, the first and second semi-fixed adhesive members410and420can maintain the configurations of being attached to the first and second semi-fixed regions212and222.

Also, embodiments are not limited thereto, and the adhesive force between the first and second semi-fixed members410and420and the first and second substrates110and120can be stronger than the adhesive force between the first and second semi-fixed adhesive members410and420and the first and second semi-fixed regions212and222. In these embodiments, when the display apparatus1000is folded, the first and second semi-fixed adhesive members410and420are detached from the first and second semi-fixed regions212and222, and the first and second semi-fixed adhesive members410and420can maintain a configuration in which the first and second semi-fixed adhesive members410and420are attached to the first and second substrates110and120.

FIG. 5is a cross-sectional view illustrating a folding angle of the display apparatus shown inFIG. 1.

Referring toFIG. 5, when the display apparatus1000is folded, a folding angle θfof the display apparatus1000can be defined. The folding angle θfcan be defined as an angle between a first extending line PL1parallel to a first upper surface111of the first substrate110and a second extending line PL2parallel to a second upper surface121of the second substrate120.

In an embodiment, when the folding angle θfis less than a predetermined attachment angle, the first and second semi-fixed adhesive members410and420are respectively detached from the first and second substrates110and120. In other words, when the folding angle θfis greater than the attachment angle, the first and second semi-fixed adhesive members410and420can maintain the configuration in which the first and second semi-fixed adhesive members410and420are attached to the first and second substrates110and120. This is because the external force (EF ofFIG. 4) acting on the first and second semi-fixed adhesive members410and420is greater than an adhesive force between the first and second semi-fixed adhesive members410and420and the first and second substrates110and120, when the folding angle θfbecomes less than the attachment angle.

Also, based on the folding angle θf, the magnitudes of stresses in the first and second semi-fixed regions212and222can be determined. For example, as the folding angle θfdecreases, the magnitudes of stresses generated in the first and second semi-fixed regions212and222increase.

When the folding angle θfis greater than the attachment angle, the stresses generated in the display panel200are less than the stress limit of the display panel200. Also, when the folding angle θfis less than the attachment angle, the stresses generated in the display panel200are greater than the stress limit of the display panel200.

Here, the stress limit is the maximum stress which does not generate a crack in the display panel200, and when a stress greater than the stress limit is applied to the display panel200, a crack may be generated in the display panel200. Thus, when the display apparatus1000is folded by an angle less than the attachment angle, stress which may occur in the display panel200can be relieved by separating the first and second semi-fixed adhesive members410and420from the first and second substrates110and120. As a result, even when the display apparatus1000is folded, the generation of crack(s) in the display panel200can be prevented, and the durability and reliability of the display apparatus1000can be improved.

FIG. 6is a graph illustrating an experiment to sample the number of cracks according to the number of times the display apparatus has been folded. A crack sample means a sample having a crack that has resulted from folding.

InFIG. 6, the x-axis denotes the number of times the display apparatus has been folded and the y-axis denotes the number of generated crack samples. InFIG. 6, a reference display apparatus and the display apparatus1000(shown inFIG. 1) according to at least one embodiment are folded, and the number of crack samples according to the number of times the respective apparatuses are folded is illustrated.

The reference display apparatus does not include the first and second semi-fixed adhesive members410and420.

As illustrated inFIG. 6, in the reference display apparatus, a crack sample occurs from 10,000 folding events or greater and the number of crack occurrences increases in proportion to the number of folding events. On the other hand, even after the display apparatus 1,000 is folded 50,000 times, it can be seen that no crack samples have occurred.

FIG. 7is a cross-sectional view of a display apparatus according to another embodiment.FIG. 8is an enlarged cross-sectional view of a region C ofFIG. 7.

Referring toFIGS. 7 and 8, the display apparatus2000is the same as the display apparatus1000except that a stress relief part or stress relief portion and auxiliary adhesive members are included instead of the first and second semi-fixed adhesive members410and420illustrated inFIG. 1. Hereinafter, the same components as those described above are denoted by the same reference numerals, and descriptions thereof will not be provided.

The stress relief part includes first and second stress relief parts or first and second stress relief portions510and520. The first stress relief part510is interposed between the first semi-fixed region212and the first substrate110. Also, the second stress relief part520is interposed between the second semi-fixed region222and the second substrate120.

The first and second stress relief parts510and520have a second flexibility. The second flexibility can be less than first flexibility of the display panel200. Accordingly, when the same magnitude of external force is applied to the first and second stress relief parts510and520and the display panel200, the first and second stress relief parts510and520can be deformed due to the external force to a greater extent than the deformation of the display panel200due to the external force.

The auxiliary adhesive members include a first upper auxiliary adhesive member611, a first lower auxiliary adhesive member612, a second upper auxiliary adhesive member621, and a second lower auxiliary adhesive member622.

The auxiliary adhesive member has adhesiveness. More specifically, the auxiliary adhesive members have a third adhesive force. The third adhesive force can be, for example, between about 2,000 through about 5,000 gf/mm. Also, in an embodiment, the auxiliary adhesive members can include acryl-based adhesive materials.

The first upper auxiliary adhesive member611is interposed between the first stress relief part510and the first semi-fixed region212, and attaches the first stress relief part510to the first semi-fixed region212. Accordingly, the first stress relief part510is not detached from the first semi-fixed region212but fixed thereto even when the display apparatus2000is folded. Also, the first lower auxiliary adhesive member612is interposed between the first stress relief part510and the first substrate110, and attaches the first stress relief part510to the first substrate110. Accordingly, the first stress relief part510is not detached from the first substrate110but fixed thereto even when the display apparatus2000is folded.

The second upper auxiliary adhesive member621is interposed between the second stress relief part520and the second semi-fixed region222, and attaches the second stress relief part520to the second semi-fixed region222. Accordingly, the second stress relief part520is not detached from the second semi-fixed region222but fixed thereto even when the display apparatus2000is folded. Also, the second lower auxiliary adhesive member622is interposed between the second stress relief part520and the second substrate120, and attaches the second stress relief part520to the second substrate120. Accordingly, the second stress relief part520is not detached from the second substrate120but fixed thereto even when the display apparatus2000is folded.

The first and second substrates110and120respectively include grooves GR recessed toward lower surfaces of the first and second substrates110and120to correspond to the first and second semi-fixed regions212and222.

As illustrated inFIG. 8, the first stress relief part510is arranged in the groove GR. Accordingly, the first lower auxiliary adhesive member612attaches a lower surface of the first stress relief part510to a lower surface of the groove GR.

A first distance DS1from the lower surface of the first substrate110to the lower surface of the first fixing region211is the same as a second distance DS2from the lower surface of the first substrate110to the lower surface of the first semi-fixed region212.

More specifically, the first thickness Th1may be substantially the same as a third thickness Th3of the first upper auxiliary adhesive member611. Also, the depth GD of the groove can be substantially the same as the sum of a fourth thickness Th4of the first stress relief part510and a fifth thickness Th5of the first lower auxiliary adhesive member612.

Accordingly, the generation of a bent portion or a concavo-convex portion, along a border of the first fixed adhesive member310and the first upper auxiliary adhesive member611, can be prevented.

FIG. 9is a cross-sectional view illustrating a folded configuration of the display apparatus shown inFIG. 8.FIG. 10is an enlarged cross-sectional view of a region D ofFIG. 9.

Referring toFIGS. 9 and 10, the display apparatus2000can be folded such that a first outer surface2111of the first fixed region211and a second outer surface2211of the second fixed region221face each other. In this configuration, since the first and second non-folded regions210and220are respectively fixed to the first and second substrates110and120which are rigid, they are not folded. On the other hand, the folding region230is folded because it is not fixed to the first or second substrates110or120. The display apparatus2000according to an embodiment, can relieve stresses concentrated at the first and second semi-fixed regions212and222when the display apparatus2000is folded.

More specifically, since the second flexibility of the first and second stress relief parts510and520is less than the first flexibility of the display panel2000, the damage to the first and second semi-fixed region212and222can be prevented when the display apparatus2000is folded.

More specifically, as illustrated inFIGS. 9 and 10, when the display apparatus2000is folded, external force EF is generated in the first and second semi-fixed regions212and222, and the external force EF acts as a stress on the first and second semi-fixed regions212and222. By means of the external force EF, the first and second stress relief parts510and520extend in a third direction D3perpendicular to the first and second substrates110and120to correspond to the external force. As a result, stresses generated in the first and second semi-fixed regions212and222can be reduced.

As a result, even if the display apparatus2000is folded, the generation of crack(s) in the display panel200can be prevented, and the durability and reliability of the display apparatus2000can be improved.

When a display apparatus according to at least one embodiment is folded, stress that is less than a stress limit of the display panel is applied to a semi-fixed area of the display panel. Accordingly, the generation of crack(s) in the display panel can be prevented, and thus the reliability and durability of the display apparatus can be improved.

While the inventive technology has been described with reference to preferred embodiments thereof, it will be readily understood by those skilled in the art that various modifications and changes can be made thereto without departing from the spirit and scope of the invention defined by the appended claims. Therefore, the scope of the inventive technology is defined not by the detailed description but by the appended claims.