Flexible substrate, method of manufacturing the same, and display apparatus employing the same

A flexible substrate includes a polymer substrate. At least a portion of a first barrier region is formed on a neutral plane of the polymer substrate. A top region is formed above the first barrier region. A bottom region is formed below the first barrier region. The first barrier region includes a first inorganic material disposed in at least a portion of a free volume of the polymer substrate. A density of the first inorganic material in the first barrier region is greater than a density of the first inorganic material in the top or bottom regions.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2016-0102439, filed on Aug. 11, 2016, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.

1. Technical Field

Exemplary embodiments of the present invention relate to a flexible substrate, and more particularly to a method of manufacturing the flexible substrate, and a display apparatus employing the flexible substrate.

2. Discussion of Related Art

A display apparatus may display visual data. The display apparatus may include a substrate including a display area and a non-display area. In the display area, a gate line and a data line may be electrically separated from each other and intersections between the gate lines and the data lines may define a plurality of pixel areas in the display area. In the display area, a thin film transistor and a pixel electrode electrically connected thereto may be connected to respective pixel areas. In the non-display area, various conductive layers such as wires transmitting electrical signals to the display area may be positioned.

A flexible display apparatus may include a bent portion or a reduced area of a foldable non-display area. The flexible display apparatus may include a flexible substrate including one or more polymer organic materials having relatively high mechanical flexibility and thermal resistance.

SUMMARY

One or more exemplary embodiments of the present invention provide a flexible substrate. The flexible substrate may be capable of reducing or preventing an infiltration of outside air. One or more exemplary embodiments of the present invention provide a method of manufacturing the flexible substrate, and a display apparatus employing the flexible substrate.

According to an exemplary embodiment of the present invention, a flexible substrate includes a polymer substrate. At least a portion of a first barrier region is formed on a neutral plane of the polymer substrate. A top region is formed above the first barrier region. A bottom region is formed below the first barrier region. The first barrier region includes a first inorganic material disposed in at least a portion of a free volume of the polymer substrate. A density of the first inorganic material in the first barrier region is greater than a density of the first inorganic material in the top or bottom regions.

According to an exemplary embodiment of the present invention, the density of the first inorganic material in the first barrier region may gradually decrease from a center thickness of the first barrier region toward upper and lower surfaces of the polymer substrate.

According to an exemplary embodiment of the present invention, the first inorganic material may include at least one of silicon nitride, aluminum nitride, zirconium nitride, titanium nitride, hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide, titanium oxide, tin oxide, serium oxide, or silicon oxynitride (SiON).

According to an exemplary embodiment of the present invention, the first inorganic material of the first barrier region may fill from about 0.1% to about 50% of a free volume of the first barrier region, and an average thickness of the first barrier region may be equal to or less than from about 5% to about 50% of a thickness of the polymer substrate.

According to an exemplary embodiment of the present invention, a position of a basic core of the first barrier region need not coincide with a position of the neutral plane.

According to an exemplary embodiment of the present invention, a thickness of the polymer substrate may be from about 10 μm to about 100 μm, and an average thickness of the first barrier region may be from about 50 nm to about 50 μm.

According to an exemplary embodiment of the present invention, the flexible substrate may include a second barrier region in at least one of the top and bottom regions. The second barrier region includes a second inorganic material disposed in at least a portion of the free volume of the polymer substrate and a volume of the second barrier region may be less than the volume of the first barrier region.

According to an exemplary embodiment of the present invention, the second inorganic material may be the same as the first inorganic material.

According to an exemplary embodiment of the present invention, a hardness of the first barrier region is greater than a hardness of the top and bottom regions.

According to an exemplary embodiment of the present invention, a method of manufacturing a flexible substrate includes injecting a first reactant above a polymer substrate into a top surface of the polymer substrate and infiltrating the first reactant into the polymer substrate. The method includes injecting a second reactant below the polymer substrate into a bottom surface of the polymer substrate and infiltrating the second reactant into the polymer substrate. The method includes forming a barrier region by filling at least a portion of a free volume of the polymer substrate with an inorganic material formed via a reaction of the first and second reactants inside the polymer substrate.

According to an exemplary embodiment of the present invention, the method may includes, after forming the barrier region, identifying whether at least one of the first and second reactants has penetrated into the polymer substrate.

According to an exemplary embodiment of the present invention, in the infiltrating of the first reactant, a pressure above the polymer substrate may be greater than a pressure below the polymer substrate.

According to an exemplary embodiment of the present invention, in the infiltrating of the second reactant, a pressure above the polymer substrate may be less than a pressure below the polymer substrate.

According to an exemplary embodiment of the present invention, the infiltrating of the first reactant and the infiltrating of the second reactant may be sequentially performed.

According to an exemplary embodiment of the present invention, the first reactant may be one of water (H2O), ozone (O3), or ammonia (NH3).

According to an exemplary embodiment of the present invention, the inorganic material formed via the reaction of the first and second reactants may include at least one of silicon nitride, aluminum nitride, zirconium nitride, titanium nitride, hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide, titanium oxide, tin oxide, serium oxide, or SiON.

According to an exemplary embodiment of the present invention, at least a portion of the barrier region may be placed on a neutral plane of the polymer substrate.

According to an exemplary embodiment of the present invention a manufacturing apparatus may be configured to manufacture the flexible substrate. The apparatus may include a first serve chamber and a second serve chamber. The polymer substrate may be disposed between side walls of the first and second serve chambers. The polymer substrate may form an airtight seal in the first and second chambers. The first serve chamber may include a first gas supplier configured to supply the first reactant, a first residual gas analyzer, and a first temperature controller, and the second serve chamber may include a second gas supplier configured to supply the second reactant, a second residual gas analyzer, and a second temperature controller.

According to an exemplary embodiment of the present invention, a method of manufacturing a flexible substrate includes infiltrating a first reactant into substantially an entire polymer substrate; and removing the first reactant infiltrated into a top region in the polymer substrate. The method includes infiltrating a second reactant into at least a portion of the polymer substrate; and forming a barrier region by filling at least a portion of a free volume of the polymer substrate with an inorganic material formed via a reaction of the first and second reactants inside the polymer substrate.

According to an exemplary embodiment of the present invention, the infiltrating of the first reactant may be performed after the polymer substrate was placed in an oven including the first reactant.

According to an exemplary embodiment of the present invention, the removing of the first reactant may be performed by applying heat to a top surface of the polymer substrate and diffusing the first reactant to outside the polymer substrate.

According to an exemplary embodiment of the present invention, the infiltrating of the second reactant may be performed inside a vacuum chamber device.

According to an exemplary embodiment of the present invention, the first reactant is one of H2O, O3, or NH3.

According to an exemplary embodiment of the present invention, the inorganic material formed via the reaction of the first and second reactants may include at least one of silicon nitride, aluminum nitride, zirconium nitride, titanium nitride, hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide, titanium oxide, tin oxide, serium oxide, or SiON.

According to an exemplary embodiment of the present invention, at least a portion of the barrier region may be placed on a neutral plane of the polymer substrate.

According to an exemplary embodiment of the present invention, after the forming of the barrier regions, identifying may be further included whether at least one of the first and second reactants penetrated through the polymer substrate.

According to an exemplary embodiment of the present invention, a display apparatus includes a flexible substrate including a display area and a non-display area. A display device is in the display area and a thin film transistor is connected to the display device. An encapsulation layer is configured to encapsulate the display area. The flexible substrate includes a polymer substrate and a first barrier region. At least a portion of the first barrier region is formed on a neutral plane of the polymer substrate. A top region is formed above the first barrier region, and a bottom region is formed below the first barrier region. The first barrier region includes a first inorganic material disposed in at least a portion of a free volume of the polymer substrate. A density of the first inorganic material in the first barrier region is greater than a density of the first inorganic material in the top or bottom regions.

According to an exemplary embodiment of the present invention, the non-display area of the flexible substrate may include a bending area bent around a bending axis. The display apparatus may include a fan-out wire with at least a portion of the fan-out wire in the bending area. The display apparatus may include an organic material layer with at least a portion or the organic material layer between the fan-out wire and the flexible substrate in the bending area.

According to an exemplary embodiment of the present invention, the display apparatus may include an inorganic insulating layer on the flexible substrate, the inorganic insulating layer having an opening corresponding to the bending area. The organic material layer may fill at least a portion of the opening.

According to an exemplary embodiment of the present invention, the display device may be an organic light-emitting diode including a pixel electrode, a counter electrode facing the pixel electrode, and an intermediate layer including an organic light-emitting layer between the pixel electrode and the counter electrode.

According to an exemplary embodiment of the present invention, a density of the first inorganic material in the first barrier region gradually may decrease from a center thickness of the first barrier region toward upper and lower ends of the flexible substrate.

According to an exemplary embodiment of the present invention, a thickness of the top region may be different from a thickness of the bottom region.

According to an exemplary embodiment of the present invention, the display apparatus may include a second barrier region in at least one of the top and bottom regions. The second barrier region includes a second inorganic material disposed in at least a portion of the free volume of the polymer substrate. A volume of the second barrier region may be less than a volume of the first barrier region.

DETAILED DESCRIPTION

Exemplary embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. In this regard, the exemplary embodiments may have different forms and should not be construed as being limited to the exemplary embodiments of the present invention described herein.

Like reference numerals may refer to like elements throughout the specification and drawings. It will be understood that although the terms “first” and “second” may be used herein to describe various components, these components should not be limited by these terms. Sizes of elements in the drawings may be exaggerated for clarity of description.

Sizes of elements in the drawings may be exaggerated for clarity of description.

When an exemplary embodiment of the present invention may be implemented differently, a specific process order may be performed differently from the described order.

FIG. 1is a cross-sectional view of a flexible substrate according to an exemplary embodiment of the present invention.FIG. 2is an enlarged view of a portion A inFIG. 1.FIG. 3is a diagram illustrating a neutral plane and strain during bending.

Referring toFIGS. 1 through 3, a flexible substrate100according to an exemplary embodiment of the present invention may include a polymer substrate101. A first barrier region103with at least a portion thereof may be on a neutral plane NP of the polymer substrate101. A top region101aof the polymer substrate101may be above the first barrier region103, and a bottom region101bof the polymer substrate101may be below the first barrier region103.

The first barrier region103may include a first inorganic material51filling at least a portion of a free volume of the polymer substrate101. A density of the first inorganic material51of the first barrier region103may be greater than that of the first inorganic material51of the top region101aand/or the bottom region101b. The first inorganic material51need not be included in the top region101aand/or the bottom region101b, and even when the first inorganic material51is included in the top region101aand/or the bottom region101b, an amount of the first inorganic material51included in the top region101aand/or the bottom region101bmay be less than that of the first inorganic material51included in the first barrier region103.

As an example, the flexible substrate100may include the first inorganic material51filling a free volume50of the polymer substrate101, and the density of the first inorganic material51may be greater near the neutral plane NP than near upper and lower surfaces of the polymer substrate101.

The polymer substrate101may include one or more polymer materials having a flexible or bendable property. According to an exemplary embodiment of the present invention, the polymer substrate101may include at least one polymer organic material, such as acrylate resin, methacrylate resin, polyisoprene, vinyl resin, urethane resin, cellulosic resin, or perylene resin. As an example, the polymer substrate101may include, for example, polymer resin such as polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyallylate, polyimide (PI), polycarbonate (PC), or cellulose acetate propionate (CAP).

The polymer substrate101may include polymer chains and the free volume50, which may be a space not occupied by polymer molecules between polymer chains. As an example, the free volume50may refer to a substantially empty space formed between polymer chains.

The polymer substrate101may be more flexible as a volume of the free volume50becomes larger. However, the free volume50may be a path through which moisture or oxygen from the outside may infiltrate. In an exemplary embodiment of the present invention, the first inorganic material51with a relatively high concentration may be formed in the first barrier region103. Thus, an overall flexibility of the flexible substrate100may be secured while an occurrence of moisture or oxygen passing through the flexible substrate100is reduced or prevented.

The first inorganic material51may substantially fill the free volume50of the polymer substrate101and thus block the path through which moisture or oxygen from the outside infiltrates into the free volume50.

When first barrier region103includes relatively more of the first inorganic material51than the top and bottom regions101aand101b, the first barrier region103may have a relatively higher hardness than that of the top region101aand the bottom region101b. When the first inorganic material51is substantially uniformly positioned throughout the entire area of the polymer substrate101, an overall hardness of the flexible substrate100may increase due to the first inorganic material51, and thus, the flexibility of the flexible substrate100may be reduced.

Thus, forming the first barrier region103to have a relatively small thickness may increase a flexibility of the flexible substrate100. When the first inorganic material51fills a portion of the free volume50of the first barrier region103, the path of moisture or gas (e.g., oxygen) may be blocked. According to an exemplary embodiment of the present invention, the first inorganic material51of the first barrier region103may fill from about 0.1% to about 50% of the free volume50of the first barrier region103, and an average thickness t of the first barrier region103may be from about 5% to about 50% of a thickness T of the flexible substrate100. According to an exemplary embodiment of the present invention, the thickness t of the first barrier region103may be less than a thickness of the top region101aor the bottom region101b.

According to an exemplary embodiment of the present invention, the thickness T of the flexible substrate100may be from about 10 μm to about 100 μm. According to an exemplary embodiment of the present invention, the thickness t of the first barrier region103may be from about 50 nm to about 50 μm.

The first barrier region103may have at least a portion thereof in the neutral plane NP of the polymer substrate101. Thus, an occurrence of a crack in the first barrier region103when the flexible substrate100bends may be reduced or prevented.

According to an exemplary embodiment of the present invention, the neutral plane NP may refer to a surface formed inside an object when the object is being bent, the object neither stretching nor shrinking along this surface so that the original length of the object remains substantially constant. As an example, the neutral plane NP may refer to a surface not affected by elongation or compression, and thus, the strain thereof may be zero. Thus, when the first barrier region103is formed on the neutral plane NP, little or no strain might occur at a time of bending the flexible substrate100, and a probability of a crack occurrence in the first inorganic material51filling the free volume50may be reduced or eliminated. However, strain due to bending may increase toward a surface of the object, and when an inorganic material with a relatively high hardness is positioned on the surface of the object, the probability of the crack occurrence may increase at the time of bending.

In an exemplary embodiment of the present invention, at least a portion of the first barrier region103may be on the neutral plane NP of the polymer substrate101. The first barrier region103may be on the neutral plane NP, but a basic core Bc of the first barrier region103along a direction of the thickness t need not coincide with the neutral plane NP. As an example, a thickness of the top region101aand a thickness of the bottom region101bmay be different from each other.

In an exemplary embodiment of the present invention, the first barrier region103may be separated from upper and lower surfaces of the polymer substrate101. At least a portion of the first barrier region103may be on the neutral plane NP of the polymer substrate101. Thus, the flexibility of the flexible substrate100may be secured and the path for infiltration from the outside air may be blocked by preventing or reducing the crack occurrence in the first barrier region103.

According to an exemplary embodiment of the present invention, the density of the first barrier region103may be relatively highest in the basic core Bc of the thickness T of the first barrier region103and may gradually decrease along directions toward upper and lower surfaces of the flexible substrate100. In a method of manufacturing the first barrier region103according to an exemplary embodiment of the present invention, a reaction of reactants forming the first inorganic material51may occur at a relatively high rate in the basic core Bc of the thickness t of the first barrier region103.

FIG. 4is a cross-sectional view of a flexible substrate according to an exemplary embodiment of the present invention. Like reference numbers denote like components inFIG. 4, as inFIG. 1, and duplicate descriptions will be omitted for the sake of simplicity.

Referring toFIG. 4, a flexible substrate100′ may include the polymer substrate101and the first barrier region103with a portion thereof on the neutral plane NP of the polymer substrate101. The first barrier region103may include the first inorganic material51filling at least a portion of the free volume50of the polymer substrate101. The density of the first inorganic material51included in the first barrier region103may be relatively higher than that of the first inorganic material51included in the top and bottom regions101aand101b.

The flexible substrate100′ may include a second barrier region105in at least one of the top region101aand the bottom region101bin addition to the first barrier region103. The second barrier region105may include a second inorganic material filling at least a portion of a free volume of the second barrier region105. A volume of the second barrier region105may be less than that of the first barrier region103.

The second barrier region105may be separated from the first barrier region103and may be formed when the first barrier region103is formed. However, exemplary embodiments of the present invention are not limited thereto. The second barrier region105may be formed via a separate process after the first barrier region103has been formed.

The second barrier region105may be formed relatively closer to upper and lower surfaces of the polymer substrate101with respect to the first barrier region103. The second inorganic material included in the second barrier region105may have a higher risk of the crack occurrence than the first inorganic material51of the first barrier region103at the time of bending the flexible substrate100′. However, even when the crack may occur in the second barrier region105, the flexible substrate100′ may have an infiltration path of outside air that is blocked by the first barrier region103.

The second inorganic material may include the same material or materials as the first inorganic material51included in the first barrier region103, or the second inorganic material may include at least one material that is different from the first inorganic material51.

The second inorganic material may include at least one of silicon nitride, aluminum nitride, zirconium nitride, titanium nitride, hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide, titanium oxide, tin oxide, serium oxide, or SiON.

At least a portion of the first barrier region103may be on the neutral plane NP of the polymer substrate101. The first barrier region103may be on the neutral plane NP, but the basic core Bc along a thickness direction of the first barrier region103need not coincide with the neutral plane NP. As an example, a thickness of the top region101a may be different from that of the bottom region101b. Depth of the basic core Bc from a surface of the polymer substrate101may be from about 5 μm to about 50 μm.

The flexible substrates100and100′ according to an exemplary embodiment of the present invention may include the first barrier region103with at least a portion thereof on the neutral plane NP of the polymer substrate101, and thus, the infiltration path of the outside air may be blocked while the flexibility of the flexible substrates100and100′ may be maintained.

FIG. 5is a flowchart of a method of manufacturing a flexible substrate according to an exemplary embodiment of the present invention.FIG. 6is a cross-sectional view of a manufacturing apparatus using the method of manufacturing ofFIG. 5.

Referring toFIGS. 5 and 6, the method of manufacturing the flexible substrates100and100′ may include infiltrating a first reactant41into the polymer substrate101from above the top surface of the polymer substrate101(S1). The method of manufacturing the flexible substrates100and100′ may include infiltrating a second reactant42into the polymer substrate101from below the bottom surface of the polymer substrate101(S2). The method of manufacturing the flexible substrates100and100′ may include forming a barrier region (e.g., the first barrier region103) inside the polymer substrate101. The barrier regions may fill the free volume of the polymer substrate101with the first inorganic material51formed via a reaction between the first reactant41and the second reactant42(S3). The method of manufacturing the flexible substrates100and100′ may include identifying whether either the first reactant41or the second reactant42has penetrated through the polymer substrate101(S4).

Referring toFIG. 6, the manufacturing apparatus according to an exemplary embodiment of the present invention may include a first serve chamber SC1and a second serve chamber SC2. The polymer substrate101may be disposed between the first serve chamber SC1and the second serve chamber SC2. The polymer substrate101may form an airtight seal in each of the first serve chamber SC1and the second serve chamber SC2. The first serve chamber SC1may be a chamber configured to supply the first reactant41to the polymer substrate101through a first gas supplier G1. The second serve chamber SC2may be a chamber configured to supply the second reactant42to the polymer substrate101through a second gas supplier G2.

The first and second serve chambers SC1and SC2may be vacuum chambers, and pressure inside the first and second serve chambers SC1and SC2may be lowered to equal to or less than about 10−6Torr.

The first and second serve chambers SC1and SC2may respectively include a first temperature controller TC1and a second temperature controller TC2. The first and second temperature controllers TC1and TC2may be hot wire type temperature controllers. The first and second temperature controllers TC1and TC2may be positioned inside the first and second serve chambers SC1and SC2, respectively, and may control temperature inside chambers via radiation heat.

The first and second serve chambers SC1and SC2may respectively include a first residual gas analyzer RGA1and a second residual gas analyzer RGA2for identifying whether either the first reactant41or the second reactant42is detected.

Each of the first and second serve chambers SC1and SC2may include at least one exhaust unit. Each of the exhaust units may be configured to exhaust gas from the first or second serve chambers SC1and SC2.

A sealing member may be disposed between a side wall of each of the first and second serve chambers SC1and SC2and the polymer substrate101. The sealing members may seal the first and second serve chambers SC1and SC2, respectively.

A process of forming a flexible substrate will be described in more detail below with reference toFIG. 5andFIG. 6. The manufacturing apparatus described with reference toFIG. 6is an exemplary apparatus; however exemplary embodiments of the present invention are not limited thereto.

The polymer substrate101may be positioned between the first and second serve chambers SC1and SC2, and the pressure inside the first and second serve chambers SC1and SC2may be maintained at equal to or less than about 10−2Torr. Viewed from above, since an area of the polymer substrate101is larger than areas of the first and second serve chambers SC1and SC2, a closed space may be formed by the first and second serve chambers SC1and SC2, and the polymer substrate101. The polymer substrate101may be provided in a roll-to-roll shape. However, exemplary embodiments of the present invention are not limited thereto.

The first reactant41may infiltrate into the polymer substrate101from above the polymer substrate101. The first reactant41may be injected into the first serve chamber SC1through the first gas supplier G1. Thus, the pressure in the first serve chamber SC1may become higher than that in the second serve chamber SC2. As an example, the pressure above the polymer substrate101may become higher than that below the polymer substrate101. The first reactant41may diffuse into the polymer substrate101due to a pressure difference between above and below the polymer substrate101. As an example, the first reactant41may infiltrate into the inside of the polymer substrate101through the top surface of the polymer substrate101and at least up to the neutral plane NP of the polymer substrate101. According to an exemplary embodiment of the present invention, when the first reactant41is injected into the first serve chamber SC1, an inside pressure of the first serve chamber SC1may be from about 10−2Torr to about 1 Torr, and an inside pressure of the second serve chamber SC2may be from about 10−6Torr to about 10−2Torr.

The second reactant42may infiltrate into the polymer substrate101from below the polymer substrate101. The second reactant42may be injected into the second serve chamber SC2through the second gas supplier G2. The second reactant42may diffuse into the polymer substrate101by controlling the pressure in the second serve chamber SC2to be higher than that in the first serve chamber SC1. As an example, the pressure above the polymer substrate101may be controlled to be lower than that below the polymer substrate101. According to an exemplary embodiment of the present invention, when the second reactant42is injected into the second serve chamber SC2, the inside pressure of the first serve chamber SC1may be from about 10−6Torr to about 10−2Torr, and that of the second serve chamber SC2may be from about 10−2Torr to about 1 Torr. The pressure in the first serve chamber SC1may be controlled such that the first reactant41is positioned near the neutral plane NP of the polymer substrate101. The second reactant42may infiltrate into the inside of the polymer substrate101through the bottom surface of the polymer substrate101and at least up to the neutral plane NP of the polymer substrate101.

The first reactant41may include a gas forming the inorganic material via a reaction with the second reactant42and need not be limited to a particular material. For example, the first reactant41may use water (H2O), ozone (O3), ammonia (NH3), oxygen (O2), hydrogen (H2), or air. According to an exemplary embodiment of the present invention, the first reactant41may be H2O. In the case of H2O, since absorption of H2O into the polymer substrate101may occur, a removal of H2O from the polymer substrate101may be performed. According to an exemplary embodiment of the present invention, H2O may be used as the first reactant41to react with the second reactant42and the removal of H2O from the polymer substrate101may be substantially simultaneously performed with formation of the first barrier region103.

The injecting of the first reactant41and the injecting of the second reactant and42may be sequentially performed. However, exemplary embodiments of the present invention are not limited thereto. The injections of the first and second reactants41and42may be substantially simultaneously performed.

The first and second reactants41and42may infiltrate into the inside of the polymer substrate101, react with each other near the neutral plane NP of the polymer substrate101, and form the first inorganic material51. The first inorganic material51may fill the free volume50of the polymer substrate101and form the first barrier region103. A desired temperature for the reaction of the first and second reactants41and42may be respectively provided via the first and second temperature controllers TC1and TC2inside the corresponding chambers.

Since the first and second reactants41and42may react with each other near the neutral plane NP of the polymer substrate101, at least a portion of the first barrier region103may be on the neutral plane NP of the polymer substrate101.

The density of the first inorganic material51may decrease from a center thickness of the first barrier region103toward upper and lower surfaces of the polymer substrate101.

When the first barrier region103is formed, the second barrier region105separated from the first barrier region103may also be formed, but a volume of the second barrier region105may be less than that of the first barrier region103.

While the first reactant41is injected into the first serve chamber SC1, whether the first reactant41has been detected in the second serve chamber SC2may be identified. This operation may be performed by the second residual gas analyzer RGA2. As an example, formation of barrier regions inside the polymer substrate101may be identified by detecting none of the first reactant41in the second serve chamber SC2. As an example, formation of barrier regions may be identified by detecting none of the second reactant42in the first serve chamber SC1while the second reactant42is injected into the second serve chamber SC2.

Since the first and second serve chambers SC1and SC2may be separated from each other via the polymer substrate101, only one reactant may be supplied to respective serve chambers SC1and SC2. Thus, contamination inside the first and second serve chambers SC1and SC2may be reduced or eliminated and formation of the first barrier region103may be identified substantially immediately by the residual gas analyzers RGA1and RGA2.

FIG. 7is a flowchart of a method of manufacturing a flexible substrate according to an exemplary embodiment of the present invention.FIGS. 8A to 8Eare diagrams illustrating a method of manufacturing a flexible substrate according to an exemplary embodiment of the present invention.

Referring toFIG. 7, a method of manufacturing the flexible substrate may include infiltrating the first reactant41into an entire portion of the polymer substrate101(SS1). The method of manufacturing the flexible substrate may include removing a portion of the first reactant41from inside the polymer substrate101(SS2). The method of manufacturing the flexible substrate may include infiltrating the second reactant42into a portion of the polymer substrate101(SS3). The method of manufacturing the flexible substrate may include forming the first barrier region103inside the polymer substrate101(SS4). The method of manufacturing the flexible substrate may include identifying whether the first reactant41was detected (SS5).

Referring toFIG. 8A, the polymer substrate101may be on a carrier substrate CS. The carrier substrate CS may be, for example, a glass substrate. The carrier substrate CS may have sufficient hardness to prevent the flexible polymer substrate101from being bent or deformed during a manufacturing process.

Referring toFIG. 8B, the polymer substrate101may be exposed to an environment having the first reactant41in a relatively high concentration and the first reactant41may infiltrate into substantially the entire polymer substrate101. The first reactant41may include a material forming an inorganic material via a reaction with the second reactant42and the first reactant41need not be limited to a particular material. For example, the first reactant41may include H2O, O3, or NH3.

According to an exemplary embodiment of the present invention, the first reactant41may include a liquid such as the water (H2O). In this case, for infiltrating the first reactant41into substantially the entire polymer substrate101, a method of immersion of the polymer substrate101in a liquid such as the water may allow the first reactant41to diffuse into substantially the entire polymer substrate101.

According to an exemplary embodiment of the present invention, the first reactant41may be a gas. In this case, for infiltrating the first reactant41into substantially the entire portion of the polymer substrate101, the polymer substrate101may be placed in a vessel such as an oven having the first reactant41in a relatively high concentration.

The first reactant41may be injected from above the polymer substrate101and allowed to diffuse after the polymer substrate101. The polymer substrate101may be positioned in a vacuum chamber maintaining a certain pressure for infiltrating the first reactant41into the polymer substrate101. Thus, it may take a relatively long amount of time for the first reactant41to diffuse into substantially the entire polymer substrate101. Thus, when a traditional atomic layer deposition (ALD) equipment or chemical vapor deposition (CVD) equipment is used for infiltrating the first reactant41into the polymer substrate101, a cost and an amount of time for diffusing the first reactant41into the polymer substrate may be relatively high.

However, an exemplary embodiment of the present invention, since the polymer substrate101is positioned in a vessel with the first reactant41in a relatively high concentration, separate vacuum equipment might not be used and thus, manufacturing time and cost may be reduced. A plurality of polymer substrates101can be simultaneously placed in a vessel having the first reactant41in a relatively high concentration, thus increasing efficiency in terms of cost and time for diffusing the first reactant41into the polymer substrate.

Referring toFIG. 8C, a portion of the first reactant41may be removed by applying heat. For example, heat may be applied from above the polymer substrate101. When heat is applied from above the polymer substrate101, the first reactant41which was diffused near the top surface of the polymer substrate101may escape from the polymer substrate101, while the first reactant41which was diffused near the bottom surface (e.g., near the carrier substrate CS) may remain.

The polymer substrate101may be positioned in a vessel having the second reactant42in a relatively high concentration for infiltrating the second reactant42into substantially the entire polymer substrate101. Since the bottom surface of the polymer substrate101may be covered by the carrier substrate CS, the second reactant42may diffuse into the inside of the polymer substrate101mainly through the top surface of the polymer substrate101. According to an exemplary embodiment of the present invention, vacuum chamber equipment may be used to infiltrate the second reactant42into the polymer substrate101. Diffusion of the second reactant42in substantially the entire polymer substrate101may be omitted. As an example, the second reactant42may be diffused only to near the neutral plane NP of the polymer substrate101to react with the first reactant41using vacuum chamber equipment. Thus, use of vacuum chamber equipment for diffusion of the second reactant42need not be disadvantageous with respect to processing time. A fact that the vacuum chamber equipment is used may illustrate that only the second reactant42is injected to react with the first reactant41after the polymer substrate101was maintained in a vacuum state before injecting the second reactant42. Thus, since the first reactant41becomes subject to a relatively low pressure in the vacuum chamber after having infiltrated down to the bottom surface of the polymer substrate101, the first reactant41may easily diffuse near the neutral plane NP of the polymer substrate101. Thus, an infiltration of other materials than the second reactant42may be reduced or prevented.

The pressure inside the vacuum chamber may increase while the second reactant42is injected. When the second reactant42is exposed to the polymer substrate101the second reactant42may diffuse toward the neutral plane NP from above the polymer substrate101, and the first reactant41near the bottom surface of the polymer substrate101may diffuse toward the top surface of the polymer substrate101. Thus, the first and second reactants41and42may react with each other near the neutral plane NP of the polymer substrate101to form the first inorganic material51. The first inorganic material51may fill the free volume50of the polymer substrate101and may form the first barrier region103, and thus, the flexible substrate100may be formed.

Since the first and second reactants41and42react with each other near the neutral plane NP of the polymer substrate101, at least a portion of the first barrier region103may be near the neutral plane NP of the polymer substrate101.

The density of the first inorganic material51may decrease from the center thickness of the first barrier region103toward upper and lower surfaces of the polymer substrate101.

When the first barrier region103is formed, the second barrier region105separated from the first barrier region103may also be formed, but a volume of the second barrier region105may be less than that of the first barrier region103.

The formed flexible substrate100may be positioned in the first and second serve chambers SC1and SC2respectively having the first and second residual gas analyzers RGA1and RGA2, and whether the first reactant41has infiltrated into the inside of chambers may be identified, and then, formation of the first barrier region103may be identified.

The flexible substrates100and100′ according to an exemplary embodiment of the present invention may be applicable in various areas. Below, a case in which the flexible substrates100and100′ are employed in a display apparatus having the bending area will be described in more detail as an example. However, the flexible substrates100and100′ may be employed in a foldable or rollable display apparatus or a display apparatus without a bending area.

A display apparatus may be an apparatus displaying an image, and may include a liquid crystal display, an electrophoretic display, an organic light-emitting display, an inorganic light-emitting display, a field emission display, a surface-conduction electron-emitter display, a plasma display, or a cathode ray display.

Below, a display apparatus according to an exemplary embodiment of the present invention will be described in more detail with the organic light-emitting display as an example. However, a display apparatus according to exemplary embodiments of the present invention is not limited thereto and various display apparatuses may include the flexible substrates according exemplary embodiments of the present invention.

FIG. 9is a perspective view of a portion of a display apparatus according to an exemplary embodiment of the present invention.FIG. 10is a cross-sectional view of a portion of the display apparatus ofFIG. 9. According to an exemplary embodiment of the present invention, a portion of a flexible substrate100included in the display apparatus may have a bent shape and thus, a portion of the display apparatus may have substantially a same bent shape as the flexible substrate100. However, the display apparatus described with reference toFIGS. 9 and 10is illustrated in an un-bent state inFIG. 10.

Referring toFIGS. 9 and 10, the flexible substrate100included in the display apparatus according to an exemplary embodiment of the present invention may be divided into a display area DA in which a display device is positioned for displaying an image and a non-display area around the display area DA. The non-display area may include a bending area BA which is bent around a bending axis BAX as a center bending axis. The bending area BA may refer to an area having a radius of curvature after bending.

The bending area BA may extend in a first direction (+y direction) and be between a first area1A and a second area2A in a second direction (+x direction) crossing the first direction. The flexible substrate100may be bent along a bending axis BAX, which extends in the first direction (+y direction), as a center.

The flexible substrate100may include the first barrier region103, and thus moisture and oxygen, which may enter from the outside, may be reduced or prevented from infiltrating into a display device300. The first barrier region103may be positioned, at least in part, in the neutral plane NP of the flexible substrate100. Thus, even when the flexible substrate100is bent in the bending area BA, the crack occurrence in the first barrier region103may be reduced or prevented.

The first area1A may include the display area DA. The first area1A may include a portion of the non-display area in addition to the display area DA. The second area2A may also include the non-display area. The bending area BA and/or the second area2A may also include the display area DA.

A plurality of pixels may display an image in the display area DA of the flexible substrate100. Elements such as a thin film transistor (TFT)210, an organic light-emitting diode (OLED), and a capacitor (Cst) may be in the display area DA.

The display area DA may include a gate line transmitting a gate signal, a data line transmitting a data signal, a driving power line transmitting power, and a common power line. The display area may include a first signal wire213b. The pixel may be configured to display the image via electrical signals provided from the TFT, the Cst, and the OLED, which are connected to the gate line, the data line, and the driving power line. The pixel P may emit light at a brightness corresponding to a driving current passing through the OLED in response to the data signal according to a driving power supplied to the pixel and the common power. The first signal wire213bmay be connected to a driving circuit unit via a fan-out wire720a. The pixel may include a plurality of pixels P, which may be arranged in various shapes such as a stripe array and a PenTile array.

The fan-out wire720amay be in the non-display area and may be connected to the first signal wire213bapplying an electrical signal to the TFT210or the display device300in the display area DA. The first signal wire213bmay correspond to various wires in the display area DA, such as the gate line GL, the data line DL, the driving power line, and the common power line. The fan-out wire720amay be connected to the first signal wire213band a portion thereof may be in the bending area BA. In an exemplary embodiment of the present invention, the fan-out wire720amay extend from the first area1A to a portion of the bending area BA or to the second area2A through the bending area BA.

The display device300may include the OLED in the display area DA. The OLED may be electrically connected to the TFT210and thus a pixel electrode310may be electrically connected to the TFT210. A thin film transistor (TFT) may be in a peripheral area outside the display area DA of the flexible substrate100. The TFT in the peripheral area may be, for example, a portion of a circuit unit for controlling an electrical signal applied to the display area DA.

The TFT210may include a semiconductor layer211, a gate electrode213, a source electrode215a, and a drain electrode215b, which may each include amorphous silicon, polycrystalline silicon, oxide semiconductor or organic semiconductor materials.

The gate electrode213may be connected to a gate wire which provides an on/off signal to the TFT210and may include a relatively low-resistance metal material. For example, the gate electrode213may have a single-layer or a multi-layer structure. Each layer may include at least one conductive material, such as, molybdenum (Mo), aluminum (Al), copper (Cu) and/or titanium (Ti).

The source electrode215aand the drain electrode215bmay have a single-layer or a multi-layer structure having relatively high conductivity. The source electrode215aand the drain electrode215bmay be respectively connected to a source area and a drain area of the semiconductor layer211. For example, the source electrode215aand the drain electrode215bmay have a single-layer or a multi-layer structure. Each layer may include at least one conductive material, such as, Al, Cu and/or Ti.

The TFT210according to an exemplary embodiment of the present invention may be a top gate type TFT in which the gate electrode213is above the semiconductor layer211, but exemplary embodiments of the present invention are not limited thereto. The TFT210according to an exemplary embodiment of the present invention may be a bottom gate type TFT in which the gate electrode213is under the semiconductor layer211.

A gate insulating layer120including inorganic materials such as silicon oxide, silicon nitride, and/or silicon oxynitride for securing insulation between the semiconductor layer211and the gate electrode213may be between the semiconductor layer211and the gate electrode213. An interlayer insulating layer130including inorganic materials such as silicon oxide, silicon nitride, and/or silicon oxynitride may be on the gate electrode213, and the source electrode215aand the drain electrode215bmay be on the interlayer insulating layer130. Insulating layers including inorganic materials may be formed via the CVD or ALD.

A buffer layer110including inorganic materials such as silicon oxide, silicon nitride, and/or silicon oxynitride may be between the TFT210and the flexible substrate100. The buffer layer110may increase flatness of a top surface of the flexible substrate100, and may prevent or reduce infiltration of impurities from the flexible substrate100to the semiconductor layer211of the TFT210. The buffer layer110may have a single-layer or multi-layer structure.

A planarization layer140may be on the TFT210. For example, when the OLED is above the TFT210, the planarization layer140may planarize a top surface of a protection layer covering the TFT210. The planarization layer140may include, for example, organic materials such as PI, acryl, benzocyclobutene (BCB), or hexamethyldisiloxane (HMDSO). The planarization layer140may have a single-layer structure; however, the planarization layer140may be variously modified. For example, the planarization layer140may have a multi-layer structure.

The OLED may include the pixel electrode310, a counter electrode330, and an intermediate layer320. The intermediate layer may be between the pixel electrode310and the counter electrode330. The OLED my include an organic light-emitting layer, and may be on the planarization layer140, in the display area DA of the flexible substrate100. The pixel electrode310may contact any one of the source electrode215aand the drain electrode215bvia an opening OP1formed in the planarization layer140. The pixel electrode310may be electrically connected to the TFT210.

A pixel definition layer150may be on the planarization layer140. The pixel definition layer150may define a pixel by having an opening corresponding to respective sub-pixels. The opening may expose at least a central portion of the pixel electrode310. The pixel definition layer150may reduce or prevent an occurrence of an arc on edges of the pixel electrode310by increasing a distance between edges of the pixel electrode310and the counter electrode330above the pixel electrode310. The pixel definition layer150may include, for example, organic materials such as PI, acryl, BCB or HMDSO.

The intermediate layer320of the OLED may include one or more relatively low molecular weight materials or polymer materials. When the intermediate layer320includes low molecular weight materials, a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and/or an electron injection layer (EIL) may have laminated structures with a single-layer or multiple layers, and may include various organic materials such as copper phthalocyanine (CuPc), N,N′-Di(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB), or tris(8-hydroxyquinoline) aluminum (Alq3). The above-described layers may be formed via a vacuum deposition method.

When the intermediate layer320includes polymer materials, the intermediate layer320may have a structure which includes an HTL and an EML. As an example, the HTL may include poly 3,4-ethylenedioxythiophene (PEDOT) and the light-emitting layer may include relatively high molecular weight (e.g., polymer) materials such as poly-phenylenevinylene (PPV) and polyfluorene. The intermediate layer320may be formed via screen printing, inkjet printing, or laser induced thermal imaging (LITI). However, exemplary embodiments of the present invention are not limited thereto, and the intermediate layer320may have various other structures. As an example, the intermediate layer320may include an integrated layer disposed on a plurality of pixel electrodes310and may include a patterned layer corresponding to each of the plurality of pixel electrodes310.

The counter electrode330may be on a top portion of the display area DA and may cover the display area DA. As an example, the counter electrode330may have an integrated structure including a plurality of OLEDs and thus, may correspond to the plurality of pixel electrodes310.

The OLED may be damaged by humidity, or oxygen from outside the OLED. An encapsulation layer400may protect the OLEDs by encapsulating the OLEDs. The encapsulation layer400may cover the display area DA and extend to the outside of the display area DA. The encapsulation layer400may include a first inorganic encapsulation layer410, an organic encapsulation layer420, and a second inorganic encapsulation layer430.

The first inorganic encapsulation layer410may cover the counter electrode330, and may include silicon oxide, silicon nitride, and/or silicon oxynitride. Other layers such as a capping layer may be between the first inorganic encapsulation layer410and the counter electrode330. The first inorganic encapsulation layer410may take on a shape of an underlying structure, and thus a top surface of the first inorganic encapsulation layer410need not be flat. The organic encapsulation layer420may cover the first inorganic encapsulation layer410, and a top surface thereof may be generally smooth. As an example, the top surface of the organic encapsulation layer420may be substantially flat in an area corresponding to the display area DA. The organic encapsulation layer420may include at least one material, such as, PET, PEN, PC, PI, PES, polyoxymethylene (POM), polyallylate, or HMDSO. The second inorganic encapsulation layer430may cover the organic encapsulation layer420, and may include silicon oxide, silicon nitride, and/or silicon oxynitride. The second inorganic encapsulation layer430may prevent the organic encapsulation layer420from being exposed to the outside by contacting the first inorganic encapsulation layer410at an edge outside the display area DA.

Since the encapsulation layer400includes the first inorganic encapsulation layer410, the organic encapsulation layer420, and the second encapsulation layer430, even when a crack occurs in the encapsulation layer400, the crack need not be connected between the first inorganic encapsulation layer410and the organic encapsulation layer420or between the organic encapsulation layer420and the second encapsulation layer430. Thus, the formation of an infiltration route of humidity or oxygen from the outside to the display area DA may be prevented or reduced.

A touch electrode710may be above the encapsulation layer400, and a cover layer730protecting the touch electrode710may be on the touch electrode710.

The touch electrode710may be connected to a touch wire720for transmitting a signal therefrom, and the touch wire720may extend to the non-display area from above the encapsulation layer400along an end surface of the encapsulation layer400. The touch wire720may be connected to the touch electrode710and at least a portion thereof may extend from above the encapsulation layer400to be in the bending area BA. According to an exemplary embodiment of the present invention, the touch wire720may extend through the bending area BA. The touch wire720may extend from above the encapsulation layer400along an end surface of the encapsulation layer400, and in this case, the end surface of the encapsulation layer400may include curves. The curves may be formed by forming steps between the planarization layer140and the pixel definition layer150. The touch wire720may extend to the non-display area with gradual slopes from above the encapsulation layer400via the curves.

The touch electrode710and the touch wire720may have a single-layer or a multi-layer structure. Each layer may include at least one material that is relatively highly conductive. For example, the touch electrode710and the touch wire720may include a single-layer or multiple layers including conductive materials, such as Al, Cu and/or Ti. The touch electrode710may include the same material as the touch wire720.

The cover layer730may be flexible, and may include polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), PI, acrylate, PET, or PEN. The cover layer730may extend to the non-display area and cover the fan-out wire720a. Thus, the cover layer730may protect both a touch electrode710and the fan-out wire720a. The cover layer730may extend from the display area DA to at least the bending area BA.

A touch buffer layer610may be between the encapsulation layer400and the touch screen layer700. The touch buffer layer610may protect the encapsulation layer400and may block an interference signal which can occur during an operation of the touch screen layer700. The touch buffer layer610may include inorganic materials such as silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, titanium oxide, or titanium nitride, or organic materials such as PI, polyester or acryl, and may include a laminated layer including one or more of the materials described above.

The touch buffer layer610may be directly formed on the encapsulation layer400via a deposition process. Since the touch screen layer700may also be directly formed on the touch buffer layer610, a separate adhesive layer may be omitted on the encapsulation layer400. Thus, a thickness of the display apparatus may be reduced.

The non-display area may include the bending area BA. The fan-out wire720a crossing the bending area BA may be included in the non-display area. The fan-out wire720amay be electrically connected to first, second, and third signal wires213b,213c, and215cwhich may apply electrical signals to the TFT210or the display device300in the display area DA. The fan-out wire720aand the first, second, and third signal wires213b,213c, and215cmay be electrically connected to each other may and may the fan-out wire720adirectly connected to the first signal wire213bvia a contact hole as well as the fan-out wire720aindirectly connected to the second or third signal wire213cor215c.

The first signal wire213bmay be electrically connected to the second or third signal wire213cor215cin the display area DA. According to an exemplary embodiment of the present invention, the second or third signal wire213cor215cmay be the gate line applying a signal to the gate electrode213. According to an exemplary embodiment of the present invention, the second or third signal wire213cor215cmay be the data line applying a signal to the source electrode215aor the drain electrode215b. According to an exemplary embodiment of the present invention, the first signal wire213bmay be connected to the second signal wire213cvia a via hole.

According to an exemplary embodiment of the present invention, the first and second signal wires213band213cmay include a same material as the gate electrode213. The third signal wire215cmay include a same material as the source electrode215aand the drain electrode215b. According to an exemplary embodiment of the present invention, the fan-out wire720amay include a same material as the third signal wire215c. Alternatively, the fan-out wire720amay include a same material as the touch wire720.

An organic material layer160may be in at least a portion of a space between the fan-out wire720aand the flexible substrate100in the bending area BA. When the display apparatus is subject to bending, the organic material layer160may reduce or prevent an occurrence of cracks in the fan-out wire720ain the bending area BA. The organic material layer160may absorb tensile stress caused by bending in the flexible substrate100and may reduce a concentration of tensile stress in the fan-out wire720a.

The organic material layer160may be substantially simultaneously formed with the planarization layer140or the pixel definition layer150, and may include a same material as the planarization layer140and/or the pixel definition layer150. As an example, the organic material layer160may be substantially simultaneously formed in a mask process for forming the planarization layer140or the pixel definition layer150and thus, a separate mask process for forming the organic material layer160may be omitted.

The buffer layer110, the gate insulating layer120and the interlayer insulating layer130may be collectively referred to as an inorganic insulating layer. The inorganic insulating layer may include an opening in a position corresponding to the bending area BA. As an example, the buffer layer110, the gate insulating layer120and the interlayer insulating layer130may respectively include openings110a,120a, and130acorresponding to the bending area BA. The openings corresponding to the bending area BA may be referred to as the openings overlapping the bending area BA. An area of each of the openings may be larger than that of the bending area BA. As an example, a width of an opening OW may be greater than a width of the bending area BA. The area of the openings may be defined as the area of the opening with the smallest area among the openings110a,120a, and130aof the buffer layer110, the gate insulating layer120, and the interlayer insulating layer130. As an example, the area of the opening may be defined as the area of the opening110aof the buffer layer110.

The display apparatus according to an exemplary embodiment of the present invention may include the organic material layer160filling at least a portion of openings of the inorganic material layer. As an example, the organic material layer160may fill all of the openings. The fan-out wire720amay extend from the first area1A to the second area2A through the bending area BA. The fan-out wire may be on the organic material layer160. The fan-out wire720amay be on the inorganic material layer, including the interlayer insulating layer130, when the organic material layer160is omitted.

Since a hardness of the inorganic insulating layer may be higher than that of the organic material layer160, a probability of the crack occurrence in the inorganic insulating layer in the bending area BA may be relatively high. When a crack occurs in the inorganic insulating layer, a probability that the crack propagates up to the fan-out wire720amay be relatively high. Thus, the propagation of the crack may be blocked by the organic material160. However, the probability of the crack occurrence in the inorganic material layer may be further reduced by forming the openings in the inorganic insulating layer. Thus, the concentration of tensile stress in the fan-out wire720amay be reduced.

Referring toFIG. 10, the organic material layer160may cover an inside surface of the openings of the inorganic material layer. A conductive material layer may be formed on substantially the entire surface of the flexible substrate100. The conductive material layer may be patterned to form various wires. When the organic material layer160does not cover the inside surface of the opening110aof the buffer layer110, the inside surface of the opening120aof the gate insulating layer120, or the inside surface of the opening130aof the interlayer insulating layer130, during a process of patterning the conductive material layer, the conductive material need not be removed from the inside surface of the opening110aof the buffer layer110, the inside surface of the opening120aof the gate insulating layer120, or the inside surface of the opening130aof the interlayer insulating layer130. In this case, the remaining conductive material may cause a short between other conductive layers. Thus, when the organic material layer160is formed, the organic material layer160may cover the inside surfaces of openings of the inorganic material layer. The organic material layer160may have a substantially uniform thickness; however, exemplary embodiments of the present invention are not limited thereto. As an example, the organic material layer160may have a different thickness depending on locations such that the organic material layer160may have the top surface thereof with a gradual curve slope near the inside surface of the opening110aof the buffer layer110, the inside surface of the opening120aof the gate insulating layer120, or the inside surface of the opening130aof the interlayer insulating layer130.

The display apparatus according to an exemplary embodiment of the present invention may employ the flexible substrate100having the first barrier region103and thus, outside air, moisture and oxygen which can infiltrate from below the flexible substrate100may be reduced or prevented from infiltrating into the inside of the display area. The first barrier region103of the flexible substrate100may be on the neutral plane NP of the flexible substrate100and thus, when the flexible substrate100is bent in the bending area BA, a crack occurrence in the first barrier region103may be reduced or prevented.

It should be understood that embodiments described herein should be considered in a descriptive sense and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments.