KR20210061104A - Flexible organic light emitting display device - Google Patents

Abstract

A flexible organic light emitting display device according to an embodiment of the present invention includes: a flexible substrate including a first base layer, a second base layer, an inorganic insulating layer between the first base layer and the second base layer; an organic light emitting device positioned on the flexible substrate; and an encapsulation layer disposed to cover the organic light emitting device. The first base layer and the second base layer include an uneven pattern. It is possible to prevent the deterioration of the device performance of a thin film transistor.

Description

Flexible organic light emitting display device {FLEXIBLE ORGANIC LIGHT EMITTING DISPLAY DEVICE}

The present specification relates to a flexible organic light emitting display device, and in particular, to a flexible organic light emitting display device capable of preventing moisture and oxygen from penetrating into the flexible organic light emitting display device and preventing peeling of a flexible substrate from occurring. will be.

The field of display devices that visually display electrical information signals is rapidly developing as the era of full-fledged information is entered, and research is being continued to develop performances such as thinner, lighter, and low power consumption for various display devices.

Typical display devices include a liquid crystal display device (LCD), a field emission display device (FED), an electro-wetting display device (EWD), and an organic light emitting display device (Organic). Light Emitting Display Device; OLED), and the like.

The organic light emitting display device is a self-luminous display device, and unlike a liquid crystal display device, it does not require a separate light source, and thus can be manufactured in a lightweight and thin form. In addition, organic light emitting display devices are not only advantageous in terms of power consumption due to low voltage driving, but also have excellent color realization, response speed, viewing angle, and contrast ratio (CR), and thus are used in various fields.

In the organic light-emitting display device, an emission layer (EML) using an organic material is disposed between two electrodes made of an anode and a cathode. When holes from the anode are injected into the emission layer and electrons from the cathode are injected into the emission layer, the injected electrons and holes recombine with each other to form excitons in the emission layer to emit light.

In this case, a host material and a dopant material are included in the emission layer, so that interaction between the two materials occurs. The host generates excitons from electrons and holes and serves to transfer energy to the dopant, and the dopant is a dye-like organic material that is added in a small amount and serves to receive energy from the host and convert it into light.

In particular, the organic light-emitting display device is formed using an organic thin film, and thus, attention is focused as an optimal material that can be applied as a flexible display device by utilizing the flexibility and elasticity characteristic of the organic thin film.

In order to implement such an organic light emitting display device as a flexible display device, a flexible material such as plastic and thin film metal is used as a substrate. In general, polyimide is often used as a substrate of an organic light emitting display device. I'm doing it.

On the other hand, such polyimide has heat resistance enough to withstand the manufacturing process of an organic light emitting display device, but has a high hygroscopicity. When polyimide having high hygroscopicity is used as a substrate of an organic light emitting display device, The device performance of the switching and driving thin film transistor is deteriorated, which in turn degrades the reliability of the organic light emitting display device.

The present invention is to solve the above problems, and provides a flexible organic light emitting display device capable of preventing deterioration of the device performance of a thin film transistor of an organic light emitting display device using polyimide as a substrate. 1 purpose.

Through this, it is a second object to improve the reliability of the flexible organic light emitting display device.

In addition, a third object is to prevent cracks from occurring in the substrate of the flexible OLED display, and to prevent moisture and oxygen from penetrating into the flexible OLED display by the cracks.

Through this, it is a fourth object to improve the reliability and lifetime of a thin film transistor and an organic light emitting device of a flexible organic light emitting display device.

Accordingly, the inventors of the present specification invented a new structure of a flexible organic light emitting display device capable of preventing the substrate and the support layer from being peeled off even when the substrate is bent.

The tasks of the present specification are not limited to the tasks mentioned above, and other tasks that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the object as described above, in the flexible organic light emitting display device according to an embodiment of the present invention, the flexible substrate includes a first base layer and an inorganic insulating layer between the second base layer and the first and second base layers. And the organic light emitting device is positioned on the flexible substrate. An encapsulation layer may be disposed to cover the organic light emitting device. The first base layer and the second base layer may include an uneven pattern.

Specific details of other embodiments are included in the detailed description and drawings.

The embodiments of the present specification can block moisture and oxygen from flowing into the flexible organic light emitting display device from the outside through the flexible substrate, thereby improving the reliability of the flexible organic light emitting display device.

In particular, there is an effect of preventing the occurrence of cracks due to the peeling phenomenon of the flexible substrate. Through this, it is possible to prevent moisture and oxygen from penetrating into the flexible organic light emitting display device. There is also an effect that can further improve reliability.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

Since the contents of the invention described in the problems to be solved above, the problem solving means, and effects do not specify essential features of the claims, the scope of the claims is not limited by the matters described in the contents of the invention.

1 is a plan view schematically illustrating a flexible organic light emitting display device according to an exemplary embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line II′ of FIG. 1.
3 is a plan view schematically illustrating a flexible organic light emitting display device according to an exemplary embodiment of the present specification.
4 is a cross-sectional view taken along line II-II' of FIG. 3.
5 is a cross-sectional view showing a flexible substrate on which the uneven pattern of FIG. 4 is formed.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms different from each other, and only these embodiments make the disclosure of the present invention complete, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to the possessor, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are exemplary, and thus the present invention is not limited to the illustrated matters. The same reference numerals refer to the same elements throughout the specification. In addition, in describing the present invention, when it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. When'include','have','consists of' and the like mentioned in the present specification are used, other parts may be added unless'only' is used. In the case of expressing the constituent elements in the singular, it includes the case of including the plural unless specifically stated otherwise.

In interpreting the constituent elements, it is interpreted as including an error range even if there is no explicit description.

In the case of a description of the positional relationship, for example, if the positional relationship of two parts is described as'upper','upper of','lower of','next to', etc.,'right' Or, unless'direct' is used, one or more other parts may be located between the two parts.

When an element or layer is referred to as “on” another element or layer, it includes all cases in which another layer or another element is interposed directly on or in the middle of another element.

Although the first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another component. Accordingly, the first component mentioned below may be a second component within the technical idea of the present invention.

The same reference numerals refer to the same elements throughout the specification.

The size and thickness of each component shown in the drawings are illustrated for convenience of description, and the present invention is not necessarily limited to the size and thickness of the illustrated component.

Each of the features of the various embodiments of the present invention may be partially or entirely combined or combined with each other, and as a person skilled in the art can fully understand, technically various interlocking and driving are possible, and each of the embodiments may be independently implemented with respect to each other. It may be possible to do it together in a related relationship.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a plan view schematically illustrating a flexible organic light emitting display device according to an exemplary embodiment of the present invention.

As shown, the flexible organic light emitting display device 100 is an organic light emitting device driven by being connected to a thin film transistor (DTr, see FIG. 2) and a thin film transistor (DTr, see FIG. 2) on a transparent flexible substrate 110 ( 160, see FIG. 2) is formed.

Looking at this in more detail, on the flexible substrate 110, an active area A/A in the center and a non-display area N/A are defined along the edges of the active area A/A, and the active area A/A A) is an area in which the organic light-emitting device 160 (refer to FIG. 2) is disposed, refers to an area in which an image is substantially displayed, and may be referred to as a display area.

In the active area A/A, a plurality of gate lines GL and data lines DL cross each other to define a plurality of pixel areas P, and each pixel area P includes an organic light emitting device 160, 2) and connected to the thin film transistor DTr (see FIG. 2) is disposed, and the thin film transistor DTr (see FIG. 2) operates in association with an externally located driving unit (not shown), and the organic light emitting device 160, 2) to control the amount of driving current provided.

Here, the non-display area N/A surrounding the edge of the active area A/A includes a pad area PAD in which the pad 130 is positioned at the upper end of the active area A/A. 130 is connected to a circuit film (not shown) such as an FPCB, and functions as a contact terminal connecting the circuit film (not shown) and the wiring 131 to each other.

That is, a printed circuit board (not shown) connected through a circuit film (not shown) such as a flexible printed circuit board (FPCB) may be connected to the pad area PAD. On the printed circuit board (not shown), a thin film transistor DTr , A data driver and a gate driver that provide a driving signal to (see FIG. 2) may be mounted.

Unlike this, it may be disposed on a circuit film (not shown) in a manner such as a chip-on-film (COF) or a tape-carrier-package (TCP), and connected to the pad area PAD of the flexible substrate 110.

A plurality of wires 131 are positioned between the pad 130 and the active region A/A, and the wires 131 transmit various electrical signals transmitted through the pad 130 to the active region A/A. It is transmitted to the arranged thin film transistor DTr (refer to FIG. 2).

In addition, the ground wiring GND is arranged around the active region A/A, and a ground voltage applied from the outside is supplied to the ground wiring GND.

Here, the flexible organic light emitting display device 100 according to the embodiment of the present invention is characterized in that the flexible substrate 110 further includes an interlayer shielding layer 110c.

Accordingly, the flexible organic light emitting display device 100 according to the embodiment of the present invention prevents the device performance of the thin film transistor (DTr, see FIG. 2) from deteriorating even when the flexible substrate 110 is made of polyimide. Through this, the reliability of the flexible organic light emitting display device 100 may also be improved.

In particular, even though the flexible substrate 110 includes the interlayer shielding layer 110c, it is possible to prevent cracks from being generated in the flexible substrate 110 by the interlayer shielding layer 110c. Through this, the flexible organic light emitting display device 100 ) It can also prevent moisture and oxygen from penetrating into the interior. Accordingly, it is also possible to prevent the reliability and lifespan of the thin film transistor DTr (refer to FIG. 2) and the organic light-emitting device 160 (refer to FIG. 2) of the flexible OLED display 100 from deteriorating.

This will be described in more detail with reference to FIG. 2.

FIG. 2 is a cross-sectional view taken along line II′ of FIG. 1.

Prior to the description, the flexible organic light emitting display device 100 according to the exemplary embodiment of the present invention is divided into a top emission type and a bottom emission type according to a transmission direction of emitted light. In the present invention, a top emission method will be described as an example.

As shown, an active area (A/A) and a non-display area (N/A) may be defined on the flexible substrate 110, and the non-display area (N/A) is the active area (A/A). It can be located on one side.

A plurality of pixel areas (P) are arranged in the active area (A/A) to display an image in the organic light emitting display device 100, and the non-display area (N/A) is an area other than the active area (A/A). As an area of, various circuits, wirings, etc. for driving the pixel area P are arranged.

Here, for convenience of explanation, the area where the thin film transistor DTr of each pixel area P of the active area A/A is located is the switching area TrA and the storage capacitors C1, C2, C3 are located. The area is defined as the storage area StgA, and the area where the pad 130 of the non-display area N/A is located is divided into a pad area PAD to be defined.

The multi-buffer layer 102 is coated on the flexible substrate 110, and the multi-buffer layer 102 is a buffer layer in which a plurality of thin films are successively stacked, for example, silicon nitride (SiNx) and silicon oxide (SiOx). ) Can be stacked alternately. Alternatively, an organic film and an inorganic film may be repeatedly stacked alternately.

The multi-buffer layer 102 serves to delay diffusion of moisture and/or oxygen penetrating the flexible substrate 110.

The active buffer layer 103 may be further positioned above the multi-buffer layer 102, and the active buffer layer 103 is for protecting the active layer 105 of the thin film transistor DTr, and flows from the flexible substrate 110. It performs the function of blocking various kinds of defects. The active buffer layer 103 may be formed of the same material as the multi-buffer layer 102, and may be formed of amorphous silicon (a-Si) or the like.

A thin film transistor DTr is located in the switching area TrA above the active buffer layer 103, and the thin film transistor DTr according to the embodiment of the present invention is a thin film transistor made of a polysilicon material as the active layer 105 and has a low temperature. An LTPS thin film transistor using polysilicon (Low Temperature Poly-Silicon; LTPS) is used.

Polysilicon materials have high mobility, low energy consumption, and excellent reliability.

That is, the active layer 105 is disposed in the switching region TrA on the active buffer layer 103. The active layer 105 of the LTPS thin film transistor (hereinafter referred to as a thin film transistor, DTr) is a channel region 105a in which a channel is formed when the thin film transistor is driven, and a source region 105b and a drain region on both sides of the channel region 105a. (105c).

The channel region 105a, the source region 105b, and the drain region 105c are defined by ion doping (impurity doping).

In this case, the active pattern 151 is formed in the storage region StgA, and the active pattern 151 is made of amorphous silicon like the active layer 105 and is doped with impurities.

Subsequently, the gate insulating layer 106 is disposed above the active layer 105 and the active pattern 151, and the gate insulating layer 106 is composed of a single layer of silicon nitride (SiNx) or silicon oxide (SiOx), or It may be composed of multiple layers made of silicon nitride (SiNx) and silicon oxide (SiOx).

In response to the switching region TrA, the gate electrode 107 is positioned on the gate insulating layer 106 so as to overlap the channel region 105a of the active layer 105, and is not shown in the drawing, but a gate wiring extending in one direction (GL in Fig. 1) is formed.

In addition, in the storage area StgA, the first metal pattern 153 is disposed on the gate insulating layer 106 to correspond to the active pattern 151.

The gate electrode 107, the gate wiring (GL in FIG. 1) and the first metal pattern 153 may be made of the same material, and the gate electrode 107 and the gate wiring (GL in FIG. 1), and the first metal pattern ( 153) may have a single layer structure made of any one of aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum (Mo), and molitanium (MoTi) having low resistance characteristics, or By consisting of two or more, it may have a double-layer or triple-layer structure.

Subsequently, a first interlayer insulating layer 108 is disposed over the gate electrode 107, the gate wiring (GL in FIG. 1) and the first metal pattern 153, and the first interlayer insulating layer 108 is formed of silicon nitride ( SiNx), so that hydrogen contained in the first interlayer insulating layer 108 made of silicon nitride (SiNx) is diffused into the active layer 105 during the hydrogenation process to stabilize the active layer 105. desirable.

In addition, in the storage area StgA, the second metal pattern 155 is disposed on the first interlayer insulating layer 108 to correspond to the first metal pattern 153. The second metal pattern 155 may be made of at least one of aluminum (Al), copper (Cu), molybdenum (Mo), chromium (Cr), nickel (Ni), tungsten (W), or an alloy thereof, and a single layer Or it may be a multi-layer structure.

A second interlayer insulating layer 109 is positioned above the first interlayer insulating layer 108 and the second metal pattern 155, and the second interlayer insulating layer 109 is formed on the entire surface of the flexible substrate 101, It may be made of silicon oxide (SiOx).

In the gate insulating layer 106 and the first and second interlayer insulating layers 108 and 109, first and second contact holes exposing the source region 105b and the drain region 105c of the active layer 105, respectively. 111a and 111b and a third contact hole 156 exposing a part of the first metal pattern 153 of the storage area StgA are provided.

The source electrode 113 and the drain electrode 115 are disposed corresponding to the switching region TrA on the first and second interlayer insulating layers 108 and 109, and the source electrode 113 and the drain electrode 115 are The source region 105b of the active layer 105 and the source region 105b of the active layer 105 respectively through the gate insulating layer 106 and the first and second contact holes 111a and 111b formed in the first and second interlayer insulating layers 108 and 109, respectively. It is connected to the drain region 105c.

The source electrode 113 and the drain electrode 115 also have the same low-resistance characteristics: aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum (Mo), molitanium (MoTi), chromium (Cr). ), titanium (Ti).

Further, although not shown in the drawing, a data line (DL in FIG. 1) that crosses the gate line (GL in FIG. 1) and defines the pixel region P is also formed.

At this time, the source electrode 113 and the drain electrode 115 and the active layer 105 including the source and drain regions 105b and 105c in contact with the electrodes 113 and 115 and are positioned above the active layer 105 The gate insulating layer 106 and the gate electrode 107 form a driving thin film transistor (DTr).

Meanwhile, although not shown in the drawing, a switching thin film transistor (not shown) is connected to the driving thin film transistor DTr, and the switching thin film transistor (not shown) has the same structure as the driving thin film transistor DTr.

In addition, the switching thin film transistor (not shown) and the driving thin film transistor DTr are shown as an example of a top gate type in which the active layer 105 is made of a polysilicon semiconductor layer, but the active layer 105 is an oxide semiconductor layer. It may be formed, or may be provided in a bottom gate type made of pure and impurity amorphous silicon.

In addition, a bottom shield metal 104 may be positioned between the active buffer layer 103 and the multi-buffer layer 102 under the active layer 105, and the lower protection metal 104 is a molybdenum (Mo) material. It can be formed using.

The lower protective metal 104 serves to suppress fluctuations in device characteristics such as a threshold voltage of the driving thin film transistor DTr due to moisture introduced from the outside. Accordingly, the lower protective metal 104 can prevent occurrence of spots and afterimages due to luminance imbalance between the pixel regions P.

In addition, the lower protective metal 104 may minimize physical damage to the thin film transistor DTr in the process of forming the flexible substrate 110 of the flexible organic light emitting display device 100.

In this case, the lower protective metal 104 may be electrically connected to one of the source electrode 113 and the drain electrode 115, through which the potential of the lower protective metal 104 is It may be prevented from changing during operation or from affecting the threshold voltage Vth of the thin film transistor DTr.

That is, if the lower protective metal 104 is in a floating state, the amount of shift in the threshold voltage of the thin film transistors DTr located in each pixel region P may vary, which is a visual defect due to an unintended luminance change. Will cause.

In the present invention, a state in which the lower protective metal 104 is connected to the drain electrode 115 is illustrated as an example. When the lower protective metal 104 and the drain electrode 115 are connected to each other, the lower protective metal 104 An equipotential is formed between) and the drain electrode 115.

Therefore, if the voltage difference between the lower protective metal 104 and the drain electrode 115 is smaller than the voltage difference between the gate electrode 107 and the source electrode 113 of the thin film transistor DTr, the lower protective metal 104 The influence on the threshold voltage of the thin film transistor DTr due to may be minimized.

In addition, in the storage area StgA, a third metal pattern 157 is positioned above the second interlayer insulating layer 109 to correspond to the second metal pattern 155, and the third metal pattern 157 is a gate It is connected to the first metal pattern 153 through the insulating layer 106 and a third contact hole 156 formed in the first and second interlayer insulating layers 108 and 109.

Here, the first metal pattern 153 becomes a second electrode (or upper electrode) of the first storage capacitor C1 and a first electrode (or lower electrode) of the second storage capacitor C2. The second metal pattern 155 becomes a second electrode (or an upper electrode) of the second storage capacitor C2 and a first electrode (or a lower electrode) of the third storage capacitor C3.

That is, the active pattern 151 and the first metal pattern 153 and the gate insulating layer 106 positioned between the active pattern 151 and the first metal pattern 153 form the first storage capacitor C1, In addition, the first interlayer insulating layer 108 positioned between the first metal pattern 153 and the second metal pattern 155 and the first metal pattern 153 and the second metal pattern 155 is a second storage capacitor C2. ). In addition, the second metal pattern 155 and the third metal pattern 157 and the second interlayer insulating layer 109 positioned between the second metal pattern 155 and the third metal pattern 157 is a third storage capacitor C3. ).

In addition, a protective layer 117 having a source electrode 113 and a drain electrode 115 and a drain contact hole 118 exposing the drain electrode 115 of the driving thin film transistor DTr over the third metal pattern 157. ) Is located.

The protective layer 117 may be formed of the same material as the gate insulating layer 106 or the first and second interlayer insulating layers 108 and 109, or may be formed of an organic insulating material to planarize the flexible substrate 101. have.

For example, the protective layer 117 is an acrylic resin, an epoxy resin, a phenolicresin, a polyamides resin, a polyimide resin, an unsaturated polyester. It may be formed of one or more of unsaturated polyesters resin, poly-phenylenethers resin, polyphenylenesulfides resin, and benzocyclobutene, but is not limited thereto. . The protective layer 117 may be formed as a single layer, or may be formed as a double or multiple layers.

The protective layer 117 may be formed to have a thickness of 2 μm to 5 μm so as to sufficiently cover the step difference on the flexible substrate 110.

Meanwhile, the protective layer 117 is applied so as to cover all of the active regions A/A, and it is preferable that the protective layer 117 does not cover all of the second interlayer insulating layer 109 positioned below.

This is because the protective layer 117, which may be formed of an organic layer, is vulnerable to moisture and air introduced from the outside, so that the protective layer 117 is not exposed to the outside of the flexible organic light emitting display device 100, This is to prevent moisture and air from flowing into the flexible organic light emitting display device 100 through the protective layer 117 made of an organic layer.

Further, the dam 140 may be disposed outside the protective layer 117, and the dam 140 is disposed so as to completely surround the active area A/A. In the dam 140, the organic protective film 123b of the protective film 123 for protecting the elements of the flexible OLED display 100 from particles (water or air) that may penetrate from the outside is formed by the dam 140 ) It functions to restrict the position to be stably within the inner area.

The dam 140 may be formed by stacking the protective layer 117 and the bank 119 and/or the spacer 121.

In this case, the wirings 131 disposed on the non-display area N/A are provided to connect to the pad 130 of the pad area PAD, and the wiring 131 may be formed of a metal having excellent conductivity. . For example, the wiring 131 may be formed of the same metal as the source electrode 113 or the drain electrode 115 of the thin film transistor DTr.

However, the present invention is not limited thereto, and the wiring 131 may be formed of the same metal as the gate electrode 107 of the thin film transistor DTr.

The pad 130 of the pad area PAD to which the wiring 131 is connected is a first pad 133 formed of the same metal as the gate electrode 107 and the same metal as the source electrode 113 or the drain electrode 115. It includes a second pad 135 formed of.

At this time, the first and second interlayer insulating layers 108 and 109 are provided with a fourth contact hole 136 exposing the first pad 133, and the first pad 133 through the fourth contact hole 136 ) And the second pad 135 come into contact with each other.

At this time, the active buffer layer 103 and the multi-buffer layer 102 are disposed under the first pad 133 to obtain the first pad 133 and the second pad from moisture and oxygen flowing from the lower portion of the flexible substrate 101. It is desirable to protect (135).

In addition, an anode electrode 161 that is connected to the drain electrode 115 of the driving thin film transistor DTr and forms an anode of the organic light emitting device 160 is positioned above the protective layer 117.

The anode electrode 211 is a laminated structure of aluminum (Al) and titanium (Ti) (Ti/Al/Ti), a laminated structure of aluminum (Al) and ITO (ITO/Al/ITO), and APC alloy (Ag/Pd/ Cu), and a metal material having a high reflectivity such as a laminated structure of APC alloy and ITO (ITO/APC/ITO).

The anode electrode 211 is positioned for each pixel region P, and a bank 119 is positioned between the anode electrodes 211 positioned for each pixel region P. That is, the anode electrode 211 has a structure that is separated for each pixel region P with the bank 119 as a boundary for each pixel region P.

A spacer 121 may be disposed on the bank 119, and the spacer 121 is disposed to surround the bank 119 to protect the organic light emitting layer 213 of the organic light emitting device 160 from external pressure. It is done.

The spacer 121 may be formed of the same resin composition as the bank 119, and may be formed of a black spacer having a high light absorption rate to prevent color mixing of light emitted from each pixel region P.

In addition, an organic emission layer 163 is positioned on the anode electrode 161. The organic emission layer 163 is a common layer formed in common in the pixel regions P, and may be a white emission layer emitting white light.

In this case, the organic light emitting layer 163 may be formed in a tandem structure of two or more stacks. Each of the stacks may include a hole transporting layer, at least one light emitting layer, and an electron transporting layer. In addition, a charge generation layer may be formed between the stacks. The charge generation layer is formed on an n-type charge generation layer and an n-type charge generation layer located adjacent to the lower stack, and p-type charge generation layer is formed adjacent to the upper stack. It may include a charge generation layer.

In addition, the n-type charge generation layer injects electrons into the lower stack, and the p-type charge generation layer injects holes into the upper stack. The n-type charge generation layer may be an organic layer doped with an alkali metal such as Li, Na, K, or Cs, or an alkaline earth metal such as Mg, Sr, Ba, or Ra in an organic host material having electron transport capability, The p-type charge generation layer may be doped with a dopant in an organic host material capable of transporting holes.

A cathode electrode 165 is located on the entire surface of the organic emission layer 163, and the cathode electrode 165 may also be formed of a common layer formed in common in the pixel regions P like the organic emission layer 163. In addition, a transparent metal material such as ITO and IZO that can transmit light (TCO, Transparent Conductive Material), or a half such as magnesium (Mg), silver (Ag), or an alloy of magnesium (Mg) and silver (Ag) It may be formed of a semitransmissive conductive material.

When the cathode electrode 165 is formed of a transflective metal material, light emission efficiency may be increased due to a micro cavity.

A capping layer may be further formed on the cathode electrode 165.

When a predetermined voltage is applied to the anode electrode 161 and the cathode electrode 165 according to the selected signal, the organic light emitting device 160 transmits holes injected from the anode electrode 161 and electrons provided from the cathode electrode 165. It is transported to the organic light-emitting layer 163 to form excitons, and when such excitons transition from an excited state to a ground state, light is generated and emitted to the outside.

At this time, the emitted light passes through the transparent cathode electrode 165 and goes out to the outside, through which the flexible organic light emitting display device 100 finally implements an arbitrary image.

And, after placing the protective film 123 in the form of a thin thin film on the driving thin film transistor (DTr) and the organic light emitting device 160, the protective film 123 and the flexible substrate 110 are bonded together to form a flexible organic light-emitting device. The light emitting display device 100 is encapsulated.

Here, the protective film 123 is used by stacking at least two inorganic protective films 123a and 123c in order to prevent external oxygen and moisture from penetrating into the flexible organic light-emitting display device 100. In this case, 2 It is preferable that an organic protective film 123b is interposed between the inorganic protective films 123a and 123c to complement the impact resistance of the inorganic protective films 123a and 123c.

Accordingly, the flexible OLED display 100 may prevent moisture and oxygen from penetrating into the flexible OLED display 100 from outside.

In addition, in the flexible organic light emitting display device 100 according to an embodiment of the present invention, a polarizing plate 170 for preventing a decrease in contrast due to external light may be positioned above the protective film 123 through which light is transmitted. That is, when the flexible organic light emitting display device 100 is in a driving mode that implements an image, by placing a polarizing plate 170 that blocks external light incident from the outside in the transmission direction of light emitted through the organic light emitting layer 213, The contrast is improved.

Here, the flexible organic light emitting display device 100 according to the embodiment of the present invention is made of a thin thin film so that the flexible substrate 110 has flexibility, and the first and second base layers 110a and 110b and , Consisting of an interlayer shielding layer 110c positioned between the first and second base layers 110a and 110b.

The first and second base layers 110a and 110b are made of polyimide, and polyimide (PI) is a polymer having a relatively low crystallinity or mostly amorphous structure. In addition to the advantages of not requiring a crosslinker for curing, it has excellent heat resistance and chemical resistance, excellent mechanical properties, electrical properties, and dimensional stability due to its transparency and rigid chain structure.

However, such polyimide is highly hygroscopic with a water vapor transmission rate (WVTR) of several to several tens of g/m224hr.

Accordingly, when the first and second base layers 110a and 110b are formed of polyimide, a large amount of moisture (H2O) is introduced from the outside through the flexible substrate 110. At this time, H+ and OH- ions of H2O are diffused toward the switching and driving thin film transistor (not shown, DTr), and the diffused ions act as a mobile charge and thus the switching and driving thin film transistor (not shown, DTr). The driving is affected by a threshold voltage and the like, and accordingly, the device performance of the switching and driving thin film transistor (not shown, DTr) is deteriorated.

Here, both the multi-buffer layer 102 and the active buffer layer 103 have a WVTR of several x 10 g/m224 hr, and are not effective in preventing the diffusion of H+ and OH- ions of H2O, so switching and driving thin film transistors (not shown, DTr), more precisely, the lower protective metal 104 is further formed under the active layer 105 to block H+ and OH- ions of moisture and/or H2O.

However, since the lower protective metal 104 is formed by partially patterning only the lower part of the active layer 105 as the lower protective metal 104 is made of a metal material, H 2 O of H + and OH- ions are accumulated in the region where the lower protective metal 104 is not present. Eventually, the switching and driving thin film transistor (not shown, DTr) is deteriorated.

Accordingly, the flexible organic light emitting display device 100 according to the embodiment of the present invention is formed by dividing the flexible substrate 110 into first and second base layers 110a and 110b, and forming the first and second base layers 110a. , 110b) to further form an interlayer shielding layer (110c).

The interlayer shielding layer 110c is made of an inorganic insulating material such as silicon nitride (SiNx) and silicon oxide (SiOx), and has a smaller WVTR than polyimide constituting the first and second base layers 110a and 110b. /1000 or less)

The interlayer shielding layer 110c is located on the front surface between the first and second base layers 110a and 110b, and almost blocks moisture permeation through the flexible substrate 110.

In the present embodiment, the inventors have found that there is also a problem related to the flexible organic light emitting display device 100 having a structure including the first and second base layers 110a and 110b and the interlayer shielding layer 110c described above.

When manufacturing the flexible organic light emitting display device 100, in order to improve the process yield, two or more flexible organic light emitting display devices 100 are manufactured together using a large substrate, and then two or more flexible organic light emitting display devices 100 are manufactured. ) Will be included in the process of separating them individually.

Here, the process of separating two or more flexible organic light emitting display devices 100 manufactured together on a large substrate is generally using a cutting means such as a cutting knife and a cutting laser, that is, two or more flexible organic light emitting display devices using a cutting means. By removing the scribing area, which is a space between the organic light emitting display devices 100, two or more flexible organic light emitting display devices 100 are separated individually.

At this time, the flexible organic light emitting display device 100 blocks the inflow of moisture and oxygen from the outside between the first and second thin base layers 110a and 110b made of polyimide so that the flexible substrate 110 has flexibility. In order to have a configuration in which the first base layer 110a, the interlayer shielding layer 110c, and the second base layer 110b are sequentially stacked and positioned by further positioning the interlayer shielding layer 110c made of an inorganic insulating material. do.

The flexible substrate 110 has different mechanical properties between the first and second base layers 110a and 110b and the interlayer shielding layer 110c, as well as the first and second base layers 110a and 110b and interlayer shielding. The interfacial adhesion between the layers 110c is weak.

Therefore, when the flexible organic light emitting display device 100 is individually separated through the cutting means or when a part of the active area A/A is folded, the flexible substrate generates stress due to folding, A peeling phenomenon occurs between the second base layers 110a and 110b and the interlayer shielding layer 110c.

In this way, the generated peeling phenomenon of the flexible substrate 110 acts as a crack, and the crack gradually propagates to the active region A/A. In addition, the crack propagated to the active area A/A becomes a penetration path of oxygen and moisture, so that the switching and driving of the flexible organic light emitting display device 100 and the thin film transistor (not shown, DTr) and the organic light emitting device 160 are Deterioration is accelerated, which in turn lowers the reliability and lifetime of the flexible organic light emitting display device 100.

Accordingly, the inventors of the present invention devised an improved structure capable of solving the above problems.

3 is a plan view schematically illustrating a flexible organic light emitting display device according to another exemplary embodiment of the present specification. 4 is a cross-sectional view taken along line II-II′ of FIG. 3.

3 and 4, the flexible substrate 210 is positioned between the first base layer 210a and the second base layer 210b made of a thin film, and the first and second base layers 210a and 210b. It may include an interlayer shielding layer (210c).

On the flexible substrate 210, an active area (A/A) in the center and a non-display area (N/A) are defined along the edges of the active area (A/A), and the active area (A/A) is an organic light emitting device. An area where (160, see FIG. 4) is disposed, refers to an area in which an image is substantially displayed, and may be referred to as a display area.

In the active area A/A, a plurality of gate lines GL and data lines DL cross each other perpendicularly to define a pixel area P.

The first and second base layers 210a and 210b are made of polyimide and have a thickness of 20 μm or less. Polyimide (PI) is a polymer having a relatively low crystallinity or mostly amorphous structure. It is easy to synthesize and can make a thin film. It has the advantage of not requiring a crosslinker for curing, as well as its transparency and rigid chain structure. As a result, it has excellent heat and chemical resistance, excellent mechanical properties, electrical properties and dimensional stability.

The interlayer shielding layer 210c is made of an inorganic insulating material such as silicon nitride (SiNx) and silicon oxide (SiOx), and may be formed to a thickness of 3000 Å or more. The inorganic insulating material has a smaller WVTR than the polyimide forming the first and second base layers 210a and 210b (about 1/1000 or less). The interlayer shielding layer 210c includes the first and second base layers 210a, 210b) can be located on the front side.

The first base layer 210a and the second base layer 210b may include an uneven pattern 210p. The concave-convex pattern 210p is formed on one surface of the first and second base layers 210a and 210b, and may be formed on the entire surface of the first and second base layers 210a and 210b, or may be disposed only in a portion thereof.

When formed on the entire surface of the first and second base layers 210a and 210b in contact with the interlayer shielding layer 210c, between the first and second base layers 210a and 210b and the interlayer shielding layer 210c There is an advantage that the peeling phenomenon can be significantly reduced. However, the flatness of the display area may decrease due to the uneven pattern 201p. If the flatness of the display area is lowered, damage may occur to the thin film transistor and/or the organic light emitting device on the upper portion of the display area, which may lead to a deterioration in display quality.

3 and 4 illustrate that the uneven pattern 210p is disposed on a portion of one surface where the first and second base layers 210a and 210b and the interlayer shielding layer 210c contact each other. That is, the uneven pattern 210p may be formed at a position corresponding to the gate line GL and the data line DL in the active region A/A. When the uneven pattern 201p is disposed at a position corresponding to the gate line GL and the data line DL of the active region A/A, the first and second base layers 210a and 210b and the interlayer shielding layer ( The adhesion between 201c) is improved, and there is no curvature due to the uneven pattern 210p in the area where the image is displayed, so that a phenomenon in which the display quality is deteriorated as described above can be prevented.

The non-display area N/A does not require a flatness of the level of the active area A/A. Therefore, the arrangement position of the uneven pattern 210p in the non-display area N/A may have a higher degree of freedom than the active area A/A. However, as described above, in the process of separating two or more flexible organic light emitting display devices manufactured together on a large substrate using cutting means such as a cutting knife and/or cutting laser, the first and the first 2 In order to prevent peeling between the base layers 210a and 210b and the interlayer shielding layer 210c, it is preferable to form an uneven pattern 210p at the ends of the first and second base layers 210a and 210b.

5 is a cross-sectional view showing a cross section of the flexible substrate 210 to explain the uneven pattern 210p.

Referring to FIG. 5, a cross section of the uneven pattern 210p may have a trapezoidal shape, and a side length may increase toward the interlayer shielding layer 210c. The concave-convex pattern 210p may be formed by patterning the first and second base layers 210a and 210b, and adhesion may be improved by expanding an adhesion area with the interlayer shielding layer 210c. In addition, since the uneven pattern 210p has a shape in which the length of the side increases toward the interlayer shielding layer 210c, a physical binding force is added, so that the adhesive strength may be further strengthened.

The flexible organic light emitting display device 200 according to the exemplary embodiment of the present invention includes the first and second base layers 210a and 210b including the interlayer shielding layer 210c and the uneven pattern 210p. 200) While it is possible to more effectively block the inflow of moisture and oxygen from the outside into the interior, it is also possible to prevent the occurrence of peeling of the flexible substrate 210.

Through this, it is possible to prevent moisture and oxygen from penetrating into the flexible organic light emitting display device 200, thereby preventing deterioration of the device performance of the switching and driving thin film transistor (not shown, DTr). Reliability of the display device 200 may also be further improved.

Although the embodiments of the present specification have been described in detail with reference to the accompanying drawings, the present specification is not necessarily limited to these embodiments, and various modifications may be made without departing from the technical idea. Accordingly, the embodiments disclosed in the present specification are not intended to limit the technical idea of the present disclosure, but to explain the technical idea, and the scope of the technical idea of the present disclosure is not limited by these embodiments. Each of the features of the various embodiments of the present invention can be partially or entirely combined or combined with each other, and can be technically variously interlocked and driven by those skilled in the art, and each of the embodiments is independently implemented with respect to each other or together in an association relationship. It can also be implemented. The scope of protection of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100, 200: flexible organic light emitting display device
102: multi-buffer layer, 103: active buffer layer, 104: lower protective metal
105: active layer 105a: channel region, 105b: source region, 105c: drain region)
106: gate insulating layer
107: gate electrode, 108, 109: first and second interlayer insulating layers
110: flexible substrate (110a, 110b; first and second base layers, 110c: interlayer shielding layer)
111a, 111b: first and second contact holes
113, 213: source electrode, 115, 215: drain electrode
117, 217: protective layer, 119, 219: bank
121, 221: spacer,
123, 223: protective film (123a, 123c: inorganic protective film, 123b: organic protective film)
130: pads 133, 135: first and second pads, 136: fourth contact hole)
131, 231: wiring, 140, 240: dam
151, 251: active pattern
153, 253: first metal pattern
155, 255: second metal pattern
156, 256: third contact hole
157, 257: third metal pattern
170, 270: polarizer
210p: Uneven pattern

Claims (20)

A flexible substrate including a first base layer, a second base layer, and an inorganic insulating layer between the first and second base layers;
An organic light emitting device positioned on the flexible substrate; And
Including an encapsulation layer disposed to cover the organic light emitting device,
The first base layer and the second base layer include an uneven pattern.
The method of claim 1,
The first base layer and the second base layer are made of polyimide (PI).
The method of claim 2,
Each of the first base layer and the second base layer has a thickness of 20 μm or less.
The method of claim 1,
The inorganic insulating layer includes at least one of silicon nitride and silicon oxide.
The method of claim 4,
A flexible organic light emitting display device having a thickness of the inorganic insulating layer of 3000 Å or more.
The method of claim 1,
The uneven pattern is a flexible organic light emitting display device in contact with the inorganic insulating layer.
The method of claim 6,
The flexible organic light emitting display device having a cross section of the uneven pattern increasing in a direction toward the inorganic insulating layer.
The method of claim 1,
A flexible organic light emitting display device comprising an active area in a central portion on the flexible substrate and a non-display area around the active area.
The method of claim 8,
The flexible organic light emitting display device further includes a gate wiring crossing the active region in a first direction and a data wiring crossing the second direction perpendicular to the first direction.
The method of claim 9,
The uneven pattern is a flexible organic light emitting display device at a position corresponding to the gate line and the data line.
The method of claim 8,
The uneven pattern is in the non-display area.
A flexible substrate including a display area and a non-display area positioned around the display area;
A gate wiring extending in a first direction in the display area and a data wiring extending in a second direction perpendicular to the first direction;
An organic light emitting device on the flexible substrate;
A display area in which the organic light-emitting device is located and a non-display area located around the display area; And
Including an encapsulation layer disposed to cover the organic light emitting device,
The flexible substrate includes a first base layer, a second base layer, and an interlayer shielding layer between the first base layer and the second base layer,
The first base layer and the second base layer are flexible organic light emitting display devices including an uneven pattern for preventing peeling.
The method of claim 12,
The uneven pattern increases a contact area with the interlayer shielding layer to prevent the first and second base layers from being separated from the interlayer shielding layer.
The method of claim 13,
The interlayer shielding layer is in a region corresponding to the data line and the gate line.
The method of claim 13,
The uneven pattern is a flexible organic light emitting display device in the entire non-display area.
The method of claim 14,
The uneven pattern is a flexible organic light emitting display device disposed on a portion including an end of the non-display area.
The method of claim 12,
The uneven pattern is a flexible organic light emitting display device provided on a surface where the first base layer and the second base layer meet the interlayer shielding layer.
The method of claim 17,
The flexible organic light emitting display device having a width of the uneven pattern increasing toward the inorganic insulating layer.
The method of claim 12,
The first base layer and the second base layer are made of polyimide.
The method of claim 12,
The interlayer shielding layer includes at least one of silicon nitride (SiNx) and silicon oxide (SiOx).

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