KR20180060187A - Flexible substrate and flexible display device including the same - Google Patents

Abstract

The present invention relates to a flexible substrate and a flexible display device including the flexible substrate. The flexible substrate of the present invention comprises a first base layer and a second base layer. The first base layer comprises a resin and an organic hybrid material. The content of the organic/inorganic hybrid material is 30 to 70 wt% of the resin content. The surface hardness of the first base layer is higher than the surface hardness of the second base layer. Accordingly, the thickness of the flexible display device can be reduced by omitting a back plate. In addition, flexibility can be improved and the problem of area limitation can be solved.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a flexible substrate and a flexible display device including the flexible substrate.

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a flexible display device, and more particularly, to a flexible substrate having lightweight, thin, and high rigidity characteristics and a flexible display device including the flexible substrate.

(LCD), an organic light emitting display (OLED) display device, an organic light emitting diode (OLED) display device, and the like have been rapidly developed in the display field for processing and displaying a large amount of information. A light emitting display device (OLED), and the like have been developed.

Among such flat panel display devices, a liquid crystal display device includes a liquid crystal panel including an upper substrate and a lower substrate bonded together with a liquid crystal layer containing liquid crystal molecules interposed therebetween as an essential component, and an electric field formed between the pixel electrode and the common electrode The liquid crystal layer is driven to display an image.

The organic light emitting display includes an anode and a cathode facing each other with an organic light emitting layer sandwiched therebetween as an essential component and holes and electrons injected from each of the anode and the cathode are combined and emitted from the organic light emitting layer, The image is displayed.

On the other hand, in recent years, a demand for a flexible display device using a flexible substrate is increasing. Since the flexible display device is portable in a folded state and displays an image in a unfolded state, the flexible display device has an advantage that it can be displayed on a large screen and is easy to carry.

1 is a schematic cross-sectional view of a conventional flexible display device.

1, a conventional flexible display device includes a display panel 10, a back plate 20 positioned below the display panel 10, a cover window 20 located above the display panel 10, (30).

In the display panel 10, an element layer including a plurality of elements is formed on the flexible substrate in a state where a carrier substrate (not shown) is attached under a flexible substrate (not shown) by releasing the release agent.

In order to protect the display panel 10 from an external impact, the cover window 30 is attached to an upper portion of the display panel 10.

Further, since the flexible substrate of the display panel 10 is very thin, a back plate 20 is attached to the back surface of the flexible substrate in order to protect the flexible substrate from the external environment.

Generally, the back plate 20 is made of polyethylene terephthalate. The back plate 20 has a thickness of 100 mu m or more in order to prevent damage such as scratches, which increases the thickness of the flexible display device and lowers the flexibility of the flexible display device.

In addition, the back plate 20 is attached to the flexible substrate of the display panel 10 through a lamination process, and the lamination process is not easy to apply to a large-area display device. Therefore, the conventional flexible display device including the back plate 20 has a limitation in increasing the area.

Meanwhile, in order to improve adhesion between the flexible substrate and the carrier substrate during the manufacturing process of the display panel 10, the flexible substrate includes a silane coupling agent. However, such a silane coupling agent may cause gas outgas in a high-temperature process, which causes a failure of the display panel 10.

An object of the present invention is to solve the problem of increased thickness and flexibility of the conventional flexible display device.

Further, the present invention aims to solve the problem of the area limitation of the conventional flexible display device.

Further, the present invention aims to solve the problem of defective by gas ejection of the conventional flexible display device.

In order to achieve the above object, a flexible substrate according to the present invention comprises a first base layer and a second base layer, wherein the first base layer comprises a resin and an organic hybrid material, and the surface of the first base layer The hardness is higher than the surface hardness of the second base layer. At this time, the organic hybrid material is a siloxane compound, and the content thereof is 30 to 70 wt% of the resin content.

The resin may be composed of melamine, acryl, urethane, epoxy or polyimide, and the second base layer may be composed of polyimide.

On the other hand, the flexible display device of the present invention includes a flexible substrate including a first substrate layer and a second substrate layer, a thin film transistor on the second substrate layer, and an organic light emitting diode or a liquid crystal capacitor connected to the thin film transistor, The base layer includes a resin and an organic hybrid material, and the surface hardness of the first base layer is higher than the surface hardness of the second base layer.

In the flexible display device including the flexible substrate according to the embodiment of the present invention, the thickness of the back plate can be omitted and the flexibility can be prevented from lowering.

Further, since the lamination process for attaching the back plate is not required, the problem of the area limitation can be solved.

In addition, it is possible to improve the adhesion to the sacrificial layer on the carrier substrate without containing the silane coupling agent, and it is possible to prevent defects due to the gas ejection due to the use of the silane coupling agent.

1 is a schematic cross-sectional view of a conventional flexible display device.
2 is a schematic cross-sectional view of a flexible display device according to an embodiment of the present invention.
3A and 3B are schematic cross-sectional views showing an example of a display panel of a flexible display device according to an embodiment of the present invention.
4 is a schematic cross-sectional view of a flexible substrate according to an embodiment of the present invention.
5 is a graph showing adhesive strength of a flexible substrate according to an embodiment of the present invention.
6 is a graph showing the adhesive strength of the flexible substrate according to the embodiment of the present invention according to the content of organic / inorganic hybrid material.
7A to 7F are cross-sectional views schematically showing a manufacturing process of a flexible display device according to an embodiment of the present invention.

The flexible substrate according to the present invention comprises a first base layer and a second base layer above the first base layer, wherein the first base layer comprises a resin and an organic hybrid material, Is higher than the surface hardness of the second base layer.

The content of the organic or inorganic hybrid material is 30 to 70 wt% of the resin content.

The organic or inorganic hybrid material is a siloxane compound.

The siloxane compound is represented by the following formula, and R1 is epoxy acrylate or urethane acrylate.

The resin is composed of melamine, acryl, urethane, epoxy or polyimide.

The second base layer is made of polyimide.

Meanwhile, the flexible display device of the present invention includes a flexible substrate including a first substrate layer and a second substrate layer, a thin film transistor on the flexible substrate, and an organic light emitting diode or a liquid crystal capacitor connected to the thin film transistor, One base layer includes a resin and an organic hybrid material, and the surface hardness of the first base layer is higher than the surface hardness of the second base layer.

The second base layer is located between the first base layer and the thin film transistor.

Hereinafter, a flexible substrate according to an embodiment of the present invention and a flexible display device including the same will be described in detail with reference to the drawings.

FIG. 2 is a schematic cross-sectional view of a flexible display device according to an embodiment of the present invention, and FIGS. 3A and 3B are schematic cross-sectional views illustrating an example of a display panel of a flexible display device according to an embodiment of the present invention.

2 and 3A and 3B, a display device according to an embodiment of the present invention includes a display panel 100 and a cover window 130 disposed on the display panel 100, The display panel 100 includes a flexible substrate 110 and an element layer 120 on the flexible substrate 110.

As shown in FIG. 3A, the display panel 100 may be an organic light emitting diode panel.

That is, the display panel 100 includes a flexible substrate 110, the thin film transistor Tr positioned on the flexible substrate 110 as the element layer 120, and a light emitting element connected to the thin film transistor Tr A diode D, and an encapsulation film 180 covering the light emitting diode D, as shown in FIG.

Here, the lower surface of the flexible substrate 110 has a surface hardness higher than that of the upper surface, and the flexible substrate 110 has a multilayer structure, which will be described later in detail.

In more detail, a buffer layer 142 is formed on the flexible substrate 110, and a thin film transistor Tr is formed on the buffer layer 142. The buffer layer 142 may be formed of an inorganic insulating material such as silicon oxide or silicon nitride. The buffer layer 142 may be omitted.

A semiconductor layer 144 is formed on the buffer layer 142. The semiconductor layer 144 may be made of an oxide semiconductor material or polycrystalline silicon.

When the semiconductor layer 144 is made of an oxide semiconductor material, a light shielding pattern (not shown) may be formed under the semiconductor layer 144. The light shielding pattern may prevent light from being incident on the semiconductor layer 144 Thereby preventing the semiconductor layer 144 from being deteriorated by light. Alternatively, the semiconductor layer 144 may be made of polycrystalline silicon. In this case, impurities may be doped on both edges of the semiconductor layer 144.

A gate insulating layer 146 made of an insulating material is formed on the semiconductor layer 144. The gate insulating layer 146 may be formed of an inorganic insulating material such as silicon oxide or silicon nitride.

A gate electrode 150 made of a conductive material such as metal is formed on the gate insulating layer 146 to correspond to the center of the semiconductor layer 144.

3A, a gate insulating film 146 is formed on the entire surface of the flexible substrate 110, but the gate insulating film 146 may be patterned in the same shape as the gate electrode 150. [

An interlayer insulating layer 152 made of an insulating material is formed on the gate electrode 150. The interlayer insulating film 152 may be formed of an inorganic insulating material such as silicon oxide or silicon nitride, or an organic insulating material such as benzocyclobutene or photo-acryl.

The interlayer insulating layer 152 has first and second contact holes 154 and 156 exposing both sides of the semiconductor layer 144. The first and second contact holes 154 and 156 are spaced apart from the gate electrode 150 on both sides of the gate electrode 150.

Here, the first and second contact holes 154 and 156 are also formed in the gate insulating film 146. Alternatively, when the gate insulating film 146 is patterned in the same shape as the gate electrode 150, the first and second contact holes 154 and 156 may be formed only in the interlayer insulating film 152.

A source electrode 160 and a drain electrode 162 made of a conductive material such as metal are formed on the interlayer insulating layer 152.

The source electrode 160 and the drain electrode 162 are spaced apart from each other around the gate electrode 150 and are connected to both sides of the semiconductor layer 144 through the first and second contact holes 154 and 156, / RTI >

The semiconductor layer 144 and the gate electrode 150, the source electrode 160 and the drain electrode 162 constitute the thin film transistor Tr, and the thin film transistor Tr includes a driving element ).

The thin film transistor Tr has a coplanar structure in which the gate electrode 150, the source electrode 160, and the drain electrode 162 are positioned above the semiconductor layer 144.

Alternatively, the thin film transistor Tr may have an inverted staggered structure in which a gate electrode is positioned below the semiconductor layer and a source electrode and a drain electrode are located above the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

Although not shown, a gate line and a data line cross each other to define a pixel region, and a switching element connected to the gate line and the data line is further formed. The switching element is connected to the thin film transistor Tr which is a driving element.

In addition, a storage capacitor is formed so that the power wiring is spaced apart in parallel to the gate wiring or the data wiring, and the voltage of the gate electrode of the thin film transistor (Tr), which is a driving element during one frame, Lt; / RTI >

A protective layer 164 having a drain contact hole 166 exposing the drain electrode 162 of the thin film transistor Tr is formed to cover the thin film transistor Tr.

A first electrode 170 connected to the drain electrode 162 of the thin film transistor Tr through the drain contact hole 166 is formed on the protective layer 164 separately for each pixel region. The first electrode 170 may be an anode and may be formed of a conductive material having a relatively large work function value. For example, the first electrode 170 may be made of a transparent conductive material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) .

Meanwhile, when the display panel 100 of the present invention is a top-emission type organic light emitting diode (OLED) panel, a reflective electrode or a reflective layer may be further formed under the first electrode 170. For example, the reflective electrode or the reflective layer may be formed of an aluminum-palladium-copper (APC) alloy.

A bank layer 176 covering the edge of the first electrode 170 is formed on the protective layer 164. The bank layer 176 exposes the center of the first electrode 170 corresponding to the pixel region.

An organic light emitting layer 172 is formed on the first electrode 170. The organic light emitting layer 172 may have a single layer structure of a light emitting material layer made of a light emitting material. Alternatively, the organic light emitting layer 172 may include a hole injection layer, a hole transporting layer, a light emitting material layer, and an electron transporting layer, which are sequentially stacked on the first electrode 170, Layer structure of an electron transporting layer and an electron injection layer.

A second electrode 174 is formed on the flexible substrate 110 on which the organic light emitting layer 172 is formed. The second electrode 174 is disposed on the front surface of the display region and is made of a conductive material having a relatively small work function value and can be used as a cathode. For example, the second electrode 174 may be formed of any one of aluminum (Al), magnesium (Mg), and aluminum-magnesium alloy (AlMg).

The first electrode 170, the organic light emitting layer 172, and the second electrode 174 form a light emitting diode (D).

An encapsulation film 180 is formed on the second electrode 174 to prevent external moisture from penetrating the light emitting diode D. The encapsulation film 180 may have a laminated structure of a first inorganic insulating layer 182, an organic insulating layer 184, and a second inorganic insulating layer 186, but is not limited thereto.

In addition, a polarizer (not shown) may be attached on the encapsulation film 180 to reduce external light reflection. For example, the polarizer may be a circular polarizer.

Meanwhile, as shown in FIG. 3B, the display panel 100 may be a reflective liquid crystal panel.

That is, the display panel 100 includes first and second flexible substrates 110 and 250 facing each other and liquid crystal molecules 262 interposed between the first and second flexible substrates 110 and 250 And a liquid crystal layer 260 formed on the substrate. Although not shown, a reflective layer is disposed between the liquid crystal layer 260 and the first flexible substrate 110.

Here, the lower surface of the flexible substrate 110 has a surface hardness higher than that of the upper surface, and the flexible substrate 110 has a multilayer structure, which will be described later in detail.

A first buffer layer 220 is formed on the first flexible substrate 110 and a thin film transistor Tr is formed on the first buffer layer 220. The first buffer layer 220 may be omitted.

A gate electrode 222 is formed on the first buffer layer 220 and a gate insulating layer 224 is formed to cover the gate electrode 222. A gate wiring (not shown) connected to the gate electrode 222 is formed on the buffer layer 220.

A semiconductor layer 226 is formed on the gate insulating layer 224 in correspondence with the gate electrode 222. The semiconductor layer 226 may be made of an oxide semiconductor material. Meanwhile, the semiconductor layer 226 may include an active layer made of amorphous silicon and an ohmic contact layer made of impurity amorphous silicon.

A source electrode 230 and a drain electrode 232 are formed on the semiconductor layer 226. In addition, a data line (not shown) connected to the source electrode 230 intersects the gate line to define a pixel region.

The gate electrode 222, the semiconductor layer 226, the source electrode 230, and the drain electrode 232 constitute a thin film transistor Tr.

A protective layer 234 having a drain contact hole 236 exposing the drain electrode 232 is formed on the thin film transistor Tr.

A pixel electrode 240 connected to the drain electrode 232 through the drain contact hole 236 and a common electrode 242 alternately arranged with the pixel electrode 240 are formed on the passivation layer 234, .

A second buffer layer 252 is formed on the second flexible substrate 250 and a black matrix (not shown) covering the non-display region, such as the thin film transistor Tr, the gate line, 254 are formed. Further, a color filter layer 256 is formed corresponding to the pixel region. The second buffer layer 252 and the black matrix 254 may be omitted.

The first and second flexible substrates 110 and 250 are bonded together with the liquid crystal layer 260 interposed therebetween and the liquid crystal layer 260 is formed by an electric field generated between the pixel electrode 240 and the common electrode 242. [ The liquid crystal molecules 262 of the liquid crystal molecules 260 are driven. The pixel electrode 240, the common electrode 242, and the liquid crystal layer 260 form a liquid crystal capacitor, and the liquid crystal capacitor is connected to the thin film transistor Tr.

Although not shown, an orientation film may be formed on each of the first and second flexible substrates 110 and 250 in contact with the liquid crystal layer 260. On the outer side of the second flexible substrate 250, A polarizing plate capable of transmitting only linearly polarized light can be attached.

The common electrode 242 is alternately arranged on the first flexible substrate 110 with the pixel electrode 240. The common electrode is formed on the entire surface of the second flexible substrate 250, The electrode 240 may be formed in a plate shape in the pixel region.

As described above, the liquid crystal panel 100 may be a reflective liquid crystal panel that uses external light as a light source and reflects and outputs external light.

Referring again to FIG. 1, the cover window 130 is located above the display panel 100. For example, the cover window 130 may be made of transparent plastic, and may be attached to the display panel 100 using an adhesive layer (not shown).

As described above, the lower surface of the flexible substrate 110 has a higher surface strength than the upper surface, and the flexible display device according to the embodiment of the present invention does not include the back plate. At this time, the surface hardness of the lower surface of the flexible substrate 110 may be 4H or more.

Hereinafter, a flexible substrate according to an embodiment of the present invention will be described in detail with reference to the drawings.

4 is a schematic cross-sectional view of a flexible substrate according to an embodiment of the present invention.

4, the flexible substrate 110 according to the embodiment of the present invention includes a first base layer 112 and a second base layer 114 on the first base layer 112 .

The first base layer 112 includes a resin and an organic hybrid material, and the first base layer 112 has a higher surface hardness than the second base layer 114.

Here, the second base layer 114 may be formed of an organic material, for example, polyimide, but is not limited thereto.

Meanwhile, the resin of the first base layer 112 may be made of melamine, acryl, urethane, epoxy, or polyimide, but is not limited thereto.

In addition, the organic or inorganic hybrid material of the first base layer 112 may be a siloxane compound, and the siloxane compound may be represented by the following formula (1).

Formula 1

Here, R1 may be an epoxy acrylate or a urethane acrylate, but is not limited thereto.

The content of the organic or inorganic hybrid material is preferably 30 to 70 wt%, more preferably 50 to 70 wt% of the resin content. That is, the content of the organic or inorganic hybrid material may be larger than the resin content. When the content of the organic / inorganic hybrid material is less than 30 wt%, the adhesion strength of the first base layer 112 to the inorganic film is lowered. Therefore, when the element layer (120 of FIG. 2) There is a problem that the adhesive layer 110 peels off. On the other hand, when the content of the organic / inorganic hybrid material is more than 70 wt%, the elasticity of the first base layer 112 is lowered and brittle, which is a problem in application to a flexible display device.

Such a flexible substrate 110 has a thickness of 20 to 70 mu m. At this time, the thickness of the first base layer 112 may be 10 to 20 占 퐉, and the thickness of the second base layer 114 may be 10 to 50 占 퐉.

As described above, the first base layer 112 has a higher surface hardness than the second base layer 114. At this time, the surface hardness of the first base layer 112 may be equal to or larger than 4H. Since the surface hardness of the first base layer 112 is higher than the surface hardness of the conventional back plate 20 (see FIG. 1) of 2H or less, the back plate can be omitted to reduce the thickness of the flexible display device and increase the flexibility , The scratch resistance can be improved.

In addition, the water vapor transmission rate (WVTR) of the first base layer 112 is about 10 ^-4 g / m ² · day, about 10 ¹ g / m ² · day (see FIG. 1 Is lower than the moisture permeability of 20), the moisture barrier property is improved.

On the other hand, the transmittance of the first base layer 112 is less than 90%, and the haze value is greater than 1.

The adhesion strength of the first base layer 112 to the inorganic film is larger than that of the second base layer 114. For example, the inorganic film may be an amorphous silicon film, and the bonding strength of the first base layer 112 to the inorganic film may be 0.3 N / cm or more, and preferably 0.3 to 1.6 N / cm.

5 is a graph showing the adhesive strength of the flexible substrate according to the embodiment of the present invention, and shows the adhesive strength to the inorganic film. Here, the flexible substrate according to an embodiment of the present invention includes a resin and a first base layer made of a organic / inorganic hybrid material of Formula 1 and a second base layer made of polyimide not containing a silane coupling agent.

As shown in Fig. 5, the flexible substrate according to the embodiment of the present invention has an adhesive strength of 0.3 N / cm or more.

On the other hand, the flexible substrate of Comparative Example 1 is made of polyimide not containing a silane coupling agent, and the flexible substrate of Comparative Example 1 has an adhesion strength of 0.05 to 0.07 N / cm.

In addition, the flexible substrate of Comparative Example 2 is made of polyimide including a silane coupling agent, and the flexible substrate of Comparative Example 2 has an adhesion strength of 0.3 to 0.4 N / cm.

As described above, the flexible substrate according to the embodiment of the present invention does not contain a silane coupling agent and has an adhesion strength higher than that of Comparative Example 2 including a silane coupling agent. Thus, at the time of forming the element layer on the flexible substrate, it is possible to prevent the flexible substrate from peeling off from the carrier substrate, and to prevent defects by the silane coupling agent.

6 is a graph showing the adhesive strength of the flexible substrate according to the embodiment of the present invention according to the content of the organic / inorganic hybrid material, and shows the adhesive strength to the inorganic film.

Here, the flexible substrate according to an embodiment of the present invention includes a resin and a first base layer made of a organic / inorganic hybrid material of Formula 1 and a second base layer made of polyimide not containing a silane coupling agent. In Experimental Example 1, the content of the organic hybrid material was 30 wt%, that in Experimental Example 2 was 50 wt%, and in Experimental Example 3, the content of the organic hybrid material was 70 wt%.

On the other hand, in the flexible substrate of the comparative example, the content of the organic hybrid material is 10 wt%.

As shown in Fig. 6, the flexible substrate according to the embodiment of the present invention has an adhesive strength of 0.3 N / cm or more.

More specifically, the flexible substrate of Experimental Example 1 had an adhesive strength of 0.37 to 0.45 N / cm, the flexible substrate of Experimental Example 2 had an adhesive strength of 0.74 to 0.80 N / cm, the flexible substrate of Experimental Example 3 had 1.51 To 1.56 N / cm.

On the other hand, the flexible substrate of the comparative example has an adhesive strength of 0.07 to 0.09 N / cm.

As described above, the adhesive strength of the flexible substrate according to the embodiment of the present invention is higher than that of the comparative example, and the adhesive strength increases as the content of the organic hybrid material increases.

On the other hand, as the content of the organic / inorganic hybrid material increases, the surface hardness increases. More specifically, the surface hardness of Experimental Example 1 is 4H, the surface hardness of Experimental Example 2 is 5 to 6H, and the surface hardness of Experimental Example 3 is 8 to 9H. On the other hand, the surface hardness of the comparative example is 3 to 4H.

Also, as the content of the organic / inorganic hybrid material increases, the transmittance decreases and the haze value increases. More specifically, the transmittance of Experimental Example 1 was 89%, the haze value was 1.18, the transmittance of Experimental Example 2 was 87%, the haze value was 2.04, the transmittance of Experimental Example 3 was 86%, and the haze value was 2.99. On the other hand, the transmittance of the comparative example is 91% and the haze value is 0.63.

A manufacturing process of the flexible display device including the flexible substrate according to the embodiment of the present invention will be described with reference to FIGS. 7A to 7F.

7A to 7F are cross-sectional views schematically showing a manufacturing process of a flexible display device according to an embodiment of the present invention.

As shown in FIG. 7A, a sacrificial layer 320 is formed on the carrier substrate 310. Here, the sacrificial layer 320 may be an inorganic film, and may be formed through a deposition process. For example, the sacrificial layer 320 may be made of amorphous silicon. In addition, the carrier substrate 310 may be made of glass.

Next, as shown in FIG. 7B, a resin including an organic hybrid material is coated on the sacrificial layer 320, and then the first base layer 112 is formed by curing the resin.

Next, as shown in FIG. 7C, a polyimide resin is coated on the first base layer 112, and then the second base layer 114 is formed by curing the polyimide resin. The first base layer 112 and the second base layer 114 form a flexible substrate 110.

Next, as shown in FIG. 7D, an element layer 120 is formed on the second base layer 114 of the flexible substrate 110. The element layer 120 includes a thin film transistor and an organic light emitting diode or a liquid crystal capacitor connected to the thin film transistor.

At this time, the adhesive strength of the first base layer 112 to the inorganic film is 0.3 to 1.6 N / cm. In the process of forming the element layer 120, the flexible substrate 110 peels off from the sacrifice layer 320 ) Can be prevented.

Next, as shown in FIG. 7E, a laser is irradiated on the back surface of the carrier substrate 310 to change the crystallinity of the sacrifice layer 320. Thus, the flexible substrate 110 on which the device layer 120 is formed is separated from the sacrificial layer 320 on the carrier substrate 310.

Thus, as shown in Fig. 7F, a display panel composed of the flexible substrate 110 and the element layer 120 is manufactured. Next, a cover window (130 in FIG. 2) is attached to the upper portion of the device layer 120 to complete the flexible display device.

As described above, in the flexible display device including the flexible substrate 110 according to the embodiment of the present invention, the thickness of the back plate can be omitted and the flexibility can be prevented from lowering. Further, since the lamination process is not required, the problem of the area limitation can be solved. Further, it is possible to improve the adhesion to the sacrificial layer 320 without containing a silane coupling agent, and it is possible to prevent defects due to the silane coupling agent.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined in the appended claims. And changes may be made without departing from the spirit and scope of the invention.

100: display panel 110: flexible substrate
120: element layer 130: cover window
112: first base layer 114: second base layer

Claims (8)

A first base layer;
The second substrate layer above the first substrate layer
/ RTI >
Wherein the first base layer comprises a resin and an organic hybrid material,
Wherein the surface hardness of the first base layer is higher than the surface hardness of the second base layer.
The method according to claim 1,
Wherein the content of the organic / inorganic hybrid material is 30 to 70 wt% of the resin content.
3. The method of claim 2,
Wherein the organic or inorganic hybrid material is a siloxane compound.
The method of claim 3,
Wherein said siloxane compound is represented by the following formula and R1 is epoxy acrylate or urethane acrylate.

The method according to claim 1,
Wherein the resin is made of melamine, acryl, urethane, epoxy or polyimide.
The method according to claim 1,
And the second base layer is made of polyimide.
A flexible substrate according to any one of claims 1 to 6;
A thin film transistor on the flexible substrate; And
An organic light emitting diode or a liquid crystal capacitor
And a flexible display device.
8. The method of claim 7,
And the second base layer is positioned between the first base layer and the thin film transistor.

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