KR102624508B1 - Flexible Electroluminescent Display Device - Google Patents

Abstract

A flexible electroluminescent display device according to an embodiment of the present invention includes a flexible substrate including a display area and a bending area extending from one side of the display area, a thin film transistor and a light emitting element in the display area, and a display area and a bending area, respectively. It includes a first planarization layer and a second planarization layer, a first wire and a second wire in the bending area, and the sum of the thicknesses of the first planarization layer and the second planarization layer in the display area is Since it is greater than the sum of the thicknesses of the first planarization layer and the second planarization layer, defects caused by cracks formed in the bending area can be minimized.

Description

Flexible Electroluminescent Display Device

This specification relates to a flexible electroluminescent display device, and more specifically, to a flexible electroluminescent display device that can minimize defects in the flexible electroluminescent display device.

As we enter the information age, the field of display devices that visually display electrical information signals is developing rapidly, and research is continuing to develop performance such as thinner, lighter, and lower power consumption for various display devices.

Representative 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), etc. may be mentioned.

An organic light emitting display device, an electroluminescent display device, is a self-luminous display device, and unlike a liquid crystal display device, it does not require a separate light source and 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 operation, but also have excellent color reproduction, response speed, viewing angle, and contrast ratio (CR), so they are expected to be utilized in various fields.

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

Additionally, the light-emitting layer contains a host material and a dopant material, and interaction between the two materials occurs. The host generates excitons from electrons and holes and transfers energy to the dopant. The dopant is a dye-like organic substance added in small amounts and serves to receive energy from the host and convert it into light.

An organic light emitting display device containing a light emitting layer made of organic material encapsulates the organic light emitting display device with glass, metal, or film to prevent moisture or oxygen from entering the organic light emitting display device from the outside. It blocks inflow to prevent oxidation of the light-emitting layer and electrode, and protects it from external mechanical or physical shock.

As display devices become smaller, efforts are being made to reduce the bezel area, which is the outer portion of the active area (A/A), in order to increase the effective display screen size in the same area of the display device.

Since wiring and driving circuits for driving the screen are generally placed in the bezel area, which is the non-active area (N/A), there was a limit to reducing the bezel area.

The recently developed flexible electroluminescent display device, which can maintain display performance even when bent by applying a flexible substrate made of a soft material such as plastic, secures area for wiring and driving circuits while reducing the bezel area. To achieve this, technology has been developed and applied to reduce the bezel area by bending the non-display area of the flexible substrate.

Additionally, electroluminescent display devices using flexible substrates such as plastic need to secure flexibility of the substrate, various insulating layers disposed on the substrate, and wiring formed of metal materials.

In the case of wiring, when the substrate on which the wiring is formed is bent, cracks may occur in the wiring due to stress caused by bending. If a crack occurs in the wiring, normal signal transmission is not achieved, so the thin film transistor or light emitting device cannot operate normally, leading to defects in the electroluminescence display device.

In the case of an insulating layer, since the inorganic or organic material that makes up the insulating layer itself has the characteristic of brittleness, the insulating layer has significantly lower flexibility compared to wiring made of metal. Therefore, when bending a substrate on which an insulating layer is formed, cracks may occur in the insulating layer due to the tensile force caused by bending.

Neutral Plane (N/P) refers to an imaginary plane that is not stressed when a structure is bent because the compressive force and tensile force applied to the structure cancel each other out. When bending, the layer placed on the upper surface relative to the neutral plane is stretched and receives a tensile force, and the layer placed on the lower surface is compressed and thus receives a compressive force. At this time, wiring or insulating layers are more vulnerable when subjected to tensile force among compressive and tensile forces of the same magnitude, so it is very important to optimize the neutral plane to avoid receiving tensile force or to minimize the size of the force even if tensile force is applied. .

Accordingly, the inventors of the present specification have invented an electroluminescent display device with a new structure that can minimize defects caused by cracks in wiring formed in a bending area of the electroluminescent display device.

In addition, the inventors of the present specification recognized that as the resolution of electroluminescent display devices gradually increases, there is a shortage of space to place wiring, and developed an electroluminescent display device with a new structure that allows wiring to be arranged more freely within a limited space. invented.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

A flexible electroluminescent display device according to an embodiment of the present invention includes a flexible substrate including a display area and a bending area extending from one side of the display area, a thin film transistor and a light emitting element in the display area, and a display area and a bending area, respectively. It includes a first planarization layer and a second planarization layer, a first wire and a second wire in the bending area, and the sum of the thicknesses of the first planarization layer and the second planarization layer in the display area is 1 greater than the sum of the thicknesses of the planarization layer and the second planarization layer.

A flexible electroluminescent display device according to an embodiment of the present invention includes the steps of forming a flexible substrate including a display area and a bending area extending from one side of the display area, forming a thin film transistor and a light emitting element in the display area, and bending. Forming a first wiring in the region, forming a first planarization layer on the thin film transistor and light emitting device in the display region, and the flexible substrate and first wiring in the bending region, using a halftone mask to form a first planarization layer in the bending region. 1 Reducing the thickness of the planarization layer, forming a second wiring on the first planarization layer in the bending area, forming a second wiring on the first planarization layer in the display area and the first planarization layer and the second wiring in the bending area. Forming a flattening layer, reducing the thickness of the second flattening layer in the bending area using a halftone mask, forming a micro cover layer on the second flattening layer in the bending area, and bending the bending area. It is manufactured so that the sum of the thicknesses of the first and second planarization layers in the bending area is smaller than the sum of the thicknesses of the first and second planarization layers in the display area.

A flexible electroluminescent display device according to an embodiment of the present invention includes a flexible substrate including a display area and a non-display area surrounding the display area and having a bending area, a thin film transistor and a light emitting element in the display area, a display area, and It includes a plurality of planarization layers in the non-display area including the bending area, wiring on each of the flexible substrate and the planarization layer, and a micro cover layer on the planarization layer in the bending area, and the neutral plane of the bending area is on the micro cover layer. It is in

The flexible electroluminescent display device according to an embodiment of the present invention has the effect of minimizing defects caused by cracks formed in the bending area by optimizing the neutral plane of the bending area by adjusting the thickness of the flattening layer in the bending area.

The flexible electroluminescent display device according to an embodiment of the present invention has the effect of allowing wiring used in the flexible electroluminescent display device to be more freely arranged within a limited space.

The effects of the flexible electroluminescent display device according to the embodiment of the present invention are not limited to the contents exemplified above, and further various effects are included in the present specification.

Since the contents of the specification described in the problem to be solved, the means to solve the problem, and the effect described above do not specify the essential features of the claim, the scope of the claim is not limited by the matters described in the content of the specification.

1 is a block diagram of an electroluminescence display device according to an embodiment of the present specification.
Figure 2 is a circuit diagram of a pixel included in an electroluminescence display device according to an embodiment of the present specification.
Figure 3 is a plan view of an electroluminescent display device according to an embodiment of the present specification.
4A and 4B are cross-sectional views of a display area and a bending area of an electroluminescence display device according to an embodiment of the present specification.
Figure 5 is a cross-sectional view of a flexible electroluminescent display device according to an embodiment of the present specification.
6A to 6I are cross-sectional views of the manufacturing process of the display area (A/A) and bending area (B/A) of the flexible electroluminescence display according to an embodiment of the present specification.
FIGS. 7A and 7B are cross-sectional views showing changes in the neutral plane according to the thickness of the planarization layer of the bending area (B/A) of the flexible electroluminescent display device according to an embodiment of the present specification.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. The present embodiments only serve to ensure that the disclosure of the present invention is complete and that common knowledge in the technical field to which the present invention pertains is not limited. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining embodiments of the present invention are illustrative, and the present invention is not limited to the matters shown. Like reference numerals refer to like elements throughout the specification. Additionally, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the plural is included unless specifically stated otherwise.

When interpreting a component, it is interpreted to include the margin of error even if there is no separate explicit description.

In the case of a description of a positional relationship, for example, if the positional relationship of two parts is described as 'on top', 'on the top', 'on the bottom', 'next to', etc., 'immediately' Alternatively, there may be one or more other parts placed between the two parts, unless 'directly' is used.

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

Each feature of the various embodiments of the present invention can be combined or combined with each other, partially or entirely, and various technological interconnections and operations are possible, and each embodiment can be implemented independently of each other or together in a related relationship. It may be possible.

Figure 1 is a block diagram of an electroluminescent display device 100 according to an embodiment of the present specification.

Referring to FIG. 1 , the electroluminescent display device 100 includes an image processing unit 110, a timing controller 120, a data driver 130, a gate driver 140, and a display panel 150.

The image processing unit 110 outputs a data enable signal (DE) in addition to a data signal (DATA) supplied from the outside. In addition to the data enable signal (DE), the image processing unit 110 may output one or more of a vertical synchronization signal, a horizontal synchronization signal, and a clock signal.

The timing controller 120 receives a data enable signal (DE) or a driving signal including a vertical synchronization signal, a horizontal synchronization signal, and a clock signal, as well as a data signal (DATA) from the image processing unit 110. The timing controller 120 includes a gate timing control signal (GDC) for controlling the operation timing of the gate driver 140 and a data timing control signal (DDC) for controlling the operation timing of the data driver 130 based on the driving signal. outputs.

The data driver 130 samples and latches the data signal (DATA) supplied from the timing controller 120 in response to the data timing control signal (DDC) supplied from the timing controller 120, converts it to a gamma reference voltage, and outputs it. . The data driver 130 outputs a data signal (DATA) through the data lines (DL1 to DLn).

The gate driver 140 outputs a gate signal while shifting the level of the gate voltage in response to the gate timing control signal (GDC) supplied from the timing controller 120. The gate driver 140 outputs a gate signal through the gate lines GL1 to GLm.

The display panel 150 displays an image as the pixel 160 emits light in response to the data signal (DATA) and gate signal supplied from the data driver 130 and the gate driver 140. The detailed structure of the pixel 160 is explained in FIGS. 2 and 3.

Figure 2 is a circuit diagram of a pixel included in an electroluminescence display device according to an embodiment of the present specification.

Referring to FIG. 2 , the pixel of the electroluminescent display device 200 includes a switching transistor 240, a driving transistor 250, a compensation circuit 260, and a light emitting element 270.

The light emitting element 270 operates to emit light according to the driving current generated by the driving transistor 250.

The switching transistor 240 performs a switching operation so that the data signal supplied through the data line 230 is stored as a data voltage in a capacitor in response to the gate signal supplied through the gate line 220.

The driving transistor 250 operates so that a constant driving current flows between the high-potential power line (VDD) and the low-potential power line (GND) in response to the data voltage stored in the capacitor.

The compensation circuit 260 is a circuit for compensating the threshold voltage of the driving transistor 350, and the compensation circuit 260 includes one or more thin film transistors and a capacitor. The composition of the compensation circuit can vary greatly depending on the compensation method.

In addition, the pixel of the electroluminescent display device 200 is composed of a 2T (Transistor) 1C (Capacitor) structure including a switching transistor 240, a driving transistor 250, a capacitor, and a light emitting element 270, but a compensation circuit ( 260) is added, it can be formed in various ways, such as 3T1C, 4T2C, 5T2C, 6T1C, 6T2C, 7T1C, 7T2C, etc.

Figure 3 is a plan view of an electroluminescent display device according to an embodiment of the present specification. Figure 3 is a plan view of the flexible substrate 310 of the flexible electroluminescent display device 300 according to an embodiment of the present invention in an unbent state.

Referring to FIG. 3, the flexible electroluminescent display device 300 has a display area (Active Area (A/A)) and a display area in which pixels that actually emit light through thin film transistors and light emitting elements are arranged on a flexible substrate 310. Includes a non-active area (N/A) surrounding the outer edge of the area (A/A).

Circuits and wiring for driving the flexible electroluminescent display device 300 may be disposed in the non-display area (N/A) of the flexible substrate 310. Additionally, it may be placed on the substrate 310 as a Gate in Panel (GIP) or connected to the flexible substrate 310 using a Tape Carrier Package (TCP) or Chip on Film (COF) method.

A bending area (B/A) can be formed by bending a portion of the non-display area (N/A) of the flexible substrate 310 in the bending direction shown by the arrow. The non-display area (N/A) of the flexible substrate 310 is where wiring and driving circuits for driving the screen are placed, and is not an area where images are displayed, so it does not need to be visible from the top of the flexible substrate 310. , by bending a portion of the non-display area (N/A) of the flexible substrate 310, the bezel area can be reduced while securing area for wiring and driving circuits.

Various wiring lines are formed on the flexible substrate 310. The wiring may be formed in the display area (A/A) of the substrate 310, or the circuit wiring 320 formed in the non-display area (N/A) may connect a driving circuit, gate driver, data driver, etc. Signals can be transmitted.

The circuit wiring 320 is made of a conductive material and may be made of a conductive material with excellent ductility to reduce the occurrence of cracks when bending the flexible substrate 410. For example, it can be formed of a conductive material with excellent ductility, such as gold (Au), silver (Ag), aluminum (Al), etc., and can be formed of one of various conductive materials used in the display area (A/A). , molybdenum (Mo), chromium (Cr), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu), and an alloy of silver (Ag) and magnesium (Mg). . Additionally, it may be composed of a multi-layer structure containing various conductive materials, for example, a three-layer structure of titanium (Ti)/aluminum (Al)/titanium (Ti), but is not limited thereto.

The circuit wiring 320 formed in the bending area (B/A) receives a tensile force when bent. For example, the circuit wiring 320 extending in the same direction as the bending direction (indicated by an arrow) on the flexible substrate 310 is subjected to the greatest tensile force, which may cause cracks. If the cracks are severe, disconnection may occur. there is. Therefore, rather than forming the circuit wiring 320 to extend in the bending direction, at least a portion of the circuit wiring 320 disposed including the bending area (B/A) extends in a diagonal direction that is different from the bending direction. By forming it, the tensile force can be minimized and the occurrence of cracks can be minimized.

The circuit wiring 420 disposed including the bending area (B/A) may be formed in various shapes, for example, a trapezoidal wave shape, a triangular wave shape, a sawtooth wave shape, a sinusoidal wave shape, an omega (Ω) shape, and a rhombus shape. It can be formed in various shapes, such as shape.

4A and 4B are cross-sectional views of a display area and a bending area of an electroluminescence display device according to an embodiment of the present specification.

FIG. 4A is a cross-sectional view of the display area (A/A) described in FIG. 3.

Referring to FIG. 4A, the substrate 410 serves to support and protect the components of the electroluminescent display device 400 disposed on the top, and recently, it can be made of a soft material with flexible characteristics. , the substrate 410 may be a flexible substrate. For example, the flexible substrate may be in the form of a film containing one of the group consisting of polyester-based polymer, silicon-based polymer, acrylic polymer, polyolefin-based polymer, and copolymers thereof.

For example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polysilane, polysiloxane, polysilazane, polycarbosilane, and polyacrylate. ), polymethacrylate, polymethylacrylate, polymethylmethacrylate, polyethylacrylate, polyethylmethacrylate, cyclic olefin copolymer ( COC), cyclic olefin polymer (COP), polyethylene (PE), polypropylene (PP), polyimide (PI), polymethyl methacrylate (PMMA), polystyrene (PS), polyacetal (POM), polyether Etherketone (PEEK), polyester sulfone (PES), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), polycarbonate (PC), polyvinylidene fluoride (PVDF), perfluoroalkyl polymer ( It may be composed of at least one of PFA), styrene acryl nitrile copolymer (SAN), and combinations thereof.

A buffer layer may be further disposed on the flexible substrate 410. The buffer layer prevents moisture or other impurities from penetrating through the flexible substrate 410 and can flatten the surface of the flexible substrate 410. The buffer layer is not an absolutely necessary component and may be removed depending on the type of flexible substrate 410 or the type of thin film transistor 420 disposed on the flexible substrate 410.

The thin film transistor 420 disposed on the flexible substrate 410 includes a gate electrode 422, a source electrode 424, a drain electrode 426, and a semiconductor layer 428.

The semiconductor layer 428 is made of amorphous silicon or polycrystalline silicon, which has better mobility than amorphous silicon, has low energy consumption and excellent reliability, and can be applied to a driving thin film transistor within a pixel. ), but is not limited to this.

Recently, oxide semiconductors have been in the spotlight for their excellent mobility and uniformity. Oxide semiconductors include indium tin gallium zinc oxide (InSnGaZnO)-based materials, which are quaternary metal oxides, indium gallium zinc oxide (InGaZnO)-based materials, which are ternary metal oxides, indium tin zinc oxide (InSnZnO)-based materials, and indium aluminum zinc oxide (InAlZnO). )-based materials, tin gallium zinc oxide (SnGaZnO)-based materials, aluminum gallium zinc oxide (AlGaZnO)-based materials, tin aluminum zinc oxide (SnAlZnO)-based materials, indium zinc oxide (InZnO)-based materials, which are binary metal oxides, tin-zinc Oxide (SnZnO) based material, aluminum zinc oxide (AlZnO) based material, zinc magnesium oxide (ZnMgO) based material, tin magnesium oxide (SnMgO) based material, indium magnesium oxide (InMgO) based material, indium gallium oxide (InGaO) based material It can be composed of indium oxide (InO)-based materials, tin oxide (SnO)-based materials, zinc oxide (ZnO)-based materials, etc., and the composition ratio of each element is not limited.

The semiconductor layer 428 may include a source region containing p-type or n-type impurities, a drain region, and a channel between the source region and the drain region. A low-concentration doping region may be included between adjacent source and drain regions.

The gate insulating layer 431 is an insulating layer composed of a single layer of silicon oxide (SiOx) or silicon nitride (SiNx) or multiple layers thereof, and prevents the current flowing in the semiconductor layer 428 from flowing to the gate electrode 422. Place it. In addition, silicon oxide is less ductile than metal, but has superior ductility than silicon nitride and can be selectively formed as a single layer or multiple layers depending on its characteristics.

The gate electrode 422 serves as a switch to turn on or off the thin film transistor 420 based on an external electrical signal transmitted through the gate line, and is made of a conductive metal. These include copper (Cu), aluminum (Al), molybdenum (Mo), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), and neodymium (Nd), and their alloys are single layer. Alternatively, it may be composed of multiple layers, but is not limited thereto.

The source electrode 424 and the drain electrode 426 are connected to the data line and allow electrical signals transmitted from the outside to be transmitted from the thin film transistor 420 to the light emitting device 440. The source electrode 424 and the drain electrode 426 are made of conductive metals such as copper (Cu), aluminum (Al), molybdenum (Mo), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), It may be composed of a single layer or multiple layers of metal materials such as neodymium (Nd) or alloys thereof, but is not limited thereto.

In order to insulate the gate electrode 422, the source electrode 424, and the drain electrode 426 from each other, an interlayer insulating layer 433 composed of a single layer or multiple layers of silicon oxide (SiOx) or silicon nitride (SiNx) is formed as the gate electrode. It can be placed between (422) and the source electrode (424) and drain electrode (426).

A passivation layer made of an inorganic insulating layer such as silicon oxide (SiOx) or silicon nitride (SiNx) may be further disposed on the thin film transistor 420. The passivation layer can prevent unnecessary electrical connections between passivation layer components and prevent contamination or damage from the outside, and may be omitted depending on the configuration and characteristics of the thin film transistor 420 and the light emitting device 440. You may.

The thin film transistor 420 can be classified into an inverted staggered structure and a coplanar structure depending on the positions of the components constituting the thin film transistor 420. In an inverted staggered thin film transistor, the gate electrode is located on the opposite side of the source electrode and drain electrode based on the semiconductor layer. As shown in FIG. 4A, in the thin film transistor 420 having a coplanar structure, the gate electrode 422 is located on the same side as the source electrode 424 and the drain electrode 426 with respect to the semiconductor layer 428.

Although FIG. 4A shows a thin film transistor 420 having a coplanar structure, the electroluminescent display device may also include a thin film transistor having an inverted staggered structure.

For convenience of explanation, only the driving thin film transistor is shown among the various thin film transistors that can be included in the electroluminescent display device, but switching thin film transistors, capacitors, etc. may also be included in the electroluminescent display device. At this time, when a signal is applied from the gate wiring, the switching thin film transistor transfers the signal from the data wiring to the gate electrode of the driving thin film transistor. The driving thin film transistor transmits the current transmitted through the power wiring to the anode by a signal received from the switching thin film transistor, and controls light emission by the current transmitted to the anode.

Protects the thin film transistor 420, alleviates the step caused by the thin film transistor 420, and reduces parasitic capacitance generated between the thin film transistor 420, the gate line, the data line, and the light emitting device 440. -Capacitance), planarization layers 435a and 437b are disposed on the thin film transistor 420.

The planarization layers 435a and 437a are made of acrylic resin, epoxy resin, phenolic resin, polyamides resin, polyimides resin, and unsaturated polyester. It may be formed of one or more of Unsaturated Polyesters Resin, Polyphenylene Resin, Polyphenylenesulfides Resin, and Benzocyclobutene, but is not limited thereto.

The electroluminescent display device according to an embodiment of the present specification may include a first planarization layer 435a and a second planarization layer 437a, which are a plurality of sequentially stacked planarization layers 435a and 437a.

For example, the first planarization layers 435a and 435b and the second planarization layers 437a and 437b respectively stacked on the display area (A/A) and the bending area (B/A) may be composed of the same layer. .

A first planarization layer 435a is stacked and disposed on the thin film transistor 420, and a second planarization layer 437a is sequentially stacked on the first planarization layer 435a.

Additionally, a buffer layer may be disposed on the first planarization layer 435a. The buffer layer is disposed to protect the components placed on the buffer layer, and may be composed of a single layer of silicon nitride (SiNx) or silicon oxide (SiOx) or multiple layers of silicon nitride (SiNx) or silicon oxide (SiOx). , may be omitted depending on the configuration and characteristics of the thin film transistor 420 and the light emitting device 440.

The intermediate electrode 430 is connected to the thin film transistor 420 through a contact hole formed in the first planarization layer 435a. The intermediate electrode 430 is stacked to be connected to the thin film transistor 420, so that the data line can also be formed in a multi-layer structure.

In addition, the data line can be formed in a structure in which a lower layer made of the same material as the source electrode 424 and the drain electrode 426 and a layer made of the same material as the middle electrode 430 are connected, so that the two lines are connected in parallel to each other. Since the data line can be implemented in this structure, the wiring resistance of the data line can be reduced.

A passivation layer made of an inorganic insulating layer such as silicon oxide (SiOx) or silicon nitride (SiNx) may be further disposed on the first planarization layer 435a and the intermediate electrode 430. The passivation layer may serve to prevent unnecessary electrical connections between components and prevent contamination or damage from the outside, and may be omitted depending on the configuration and characteristics of the thin film transistor 420 and the light emitting device 440.

The manufacturing process of the planarization layers 435a, 435b, 437a, and 437b disposed in the display area (A/A) and bending area (B/A) will be described with reference to FIGS. 6A to 6I.

The light emitting device 440 disposed on the second planarization layer 437a includes an anode 442, a light emitting portion 444, and a cathode 446.

The anode 442 may be disposed on the second planarization layer 437a.

The anode 442 is an electrode that supplies holes to the light emitting unit 444, and is connected to the intermediate electrode 430 through a contact hole in the second planarization layer 437a, and is electrically connected to the thin film transistor 420. It is connected to

The anode 442 may be made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO), but is not limited thereto.

If the electroluminescent display device 400 is a top emission device that emits light toward the top where the cathode 446 is placed, the emitted light is reflected from the anode 442 and the cathode 446 is positioned more smoothly. It may further include a reflective layer so that it can be emitted in the upper direction.

For example, the anode 442 may have a two-layer structure in which a transparent conductive layer made of a transparent conductive material and a reflective layer are sequentially stacked, or it may have a three-layer structure in which a transparent conductive layer, a reflective layer, and a transparent conductive layer are sequentially stacked, and the reflective layer is It may be silver (Ag) or an alloy containing silver.

The bank 450 disposed on the anode 442 and the second planarization layer 437a may define a pixel that can define an area that actually emits light. After forming photoresist on the anode 442, the bank 450 is formed by photolithography. Photoresist refers to a photosensitive resin whose solubility in a developer changes under the action of light, and a specific pattern can be obtained by exposing and developing the photoresist. Photoresist can be classified into positive photoresist and negative photoresist. Positive photoresist refers to a photoresist whose solubility in the developer of the exposed area increases with exposure. When a positive photoresist is developed, a pattern with the exposed area removed is obtained. In addition, negative photoresist refers to a photoresist whose solubility in the developer of the exposed area is greatly reduced by exposure. When the negative photoresist is developed, a pattern with the non-exposed area removed is obtained.

To form the light emitting portion 444 of the light emitting device 440, a fine metal mask (FMM), which is a deposition mask, can be used. In addition, in order to prevent damage that may occur by contact with the deposition mask disposed on the bank 450 and to maintain a constant distance between the bank 450 and the deposition mask, a transparent organic polyethylene layer is placed on the top of the bank 450. A spacer (452) composed of one of mead, photoacrylic, and benzocyclobutene (BCB) may be placed.

A light emitting unit 444 is disposed between the anode 442 and the cathode 446. The light emitting part 444 serves to emit light, and includes a hole injection layer (HIL), a hole transport layer (HTL), a light emitting layer, an electron transport layer (ETL), and an electron injection layer. (Electron Injection Layer; EIL), and some components of the light emitting unit 444 may be omitted depending on the structure or characteristics of the electroluminescence display device 400. Here, it is also possible to apply an organic light emitting layer or an inorganic light emitting layer as the light emitting layer.

The hole injection layer is disposed on the anode 442 to facilitate hole injection. The hole injection layer is, for example, HAT-CN (dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10.11-hexacarbonitrile), CuPc (phthalocyanine), and It may be composed of one or more of NPD (N,N'-bis(naphthalene-1-yl)-N,N'-bis(phenyl)-2,2'-dimethylbenzidine).

The hole transport layer is disposed on the hole injection layer and serves to smoothly transfer holes to the light emitting layer. The hole transport layer is, for example, NPD (N,N'-bis(naphthalene-1-yl)-N,N'-bis(phenyl)-2,2'-dimethylbenzidine), TPD(N,N'-bis -(3-methylphenyl)-N,N'-bis-(phenyl)-benzidine), s-TAD(2,2',7,7'-tetrakis(N,N-dimethylamino)-9,9-spirofluorene) , and MTDATA (4,4',4"-Tris(N-3-methylphenyl-N-phenyl-amino)-triphenylamine).

The light-emitting layer is disposed on the hole transport layer and can emit light of a specific color by including a material that can emit light of a specific color. Also, the light-emitting material can be formed using a phosphorescent material or a fluorescent material.

When the light-emitting layer emits red, the peak wavelength of light emission may be in the range of 600 nm to 650 nm, and CBP (4,4'-bis(carbazol-9-yl)biphenyl) or mCP (1,3 -Contains host materials including bis(carbazol-9-yl)benzene), PIQIr(acac)(bis(1-phenylisoquinoline)(acetylacetonate) iridium), PQIr(acac)(bis(1-phenylquinoline)(acetylacetonate) ) iridium), tris(1-phenylquinoline) iridium (PQIr), and octaethylporphyrin platinum (PtOEP). Alternatively, it may be made of a fluorescent material containing PBD:Eu(DBM)3(Phen) or Perylene.

Here, the peak wavelength (λmax) refers to the maximum wavelength of EL (ElectroLuminescence). The wavelength at which the light-emitting layers that make up the light-emitting part emit their own light is called PL (PhotoLuminescence), and the light that comes out under the influence of the thickness or optical characteristics of the layers that make up the light-emitting layer is called emittance. At this time, EL (ElectroLuminescence) refers to the light finally emitted by the electroluminescence display device, and can be expressed as the product of PL (PhotoLuminescence) and emittance.

When the light emitting layer emits green, the peak wavelength of light emission may be in the range of 520 nm to 540 nm, and includes a host material containing CBP or mCP, and Ir(ppy) ₃ (tris(2-phenylpyridine)iridium ) may be made of a phosphorescent material containing a dopant material such as an Ir complex containing. Additionally, it may be made of a fluorescent material containing Alq ₃ (tris(8-hydroxyquinolino)aluminum).

When the light emitting layer emits blue, the peak wavelength of light emission may be in the range of 440 nm to 480 nm, contains a host material containing CBP or mCP, and FIrPic (bis(3,5-difluoro-2 It may be made of a phosphorescent material containing a dopant material containing -(2-pyridyl)phenyl-(2-carboxypyridyl)iridium). In addition, spiro-DPVBi(4,4'-Bis(2,2-diphenyl-ethen) -1-yl)biphenyl), DSA (1-4-di-[4-(N,N-di-phenyl)amino]styryl-benzene), PFO (polyfluorene) polymer, and PPV (polyphenylenevinylene) polymer. It may be made of a fluorescent material containing one.

An electron transport layer is placed on the light emitting layer to facilitate the movement of electrons to the light emitting layer. The electron transport layer is, for example, Liq (8-hydroxyquinolinolato-lithium), PBD (2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole), TAZ (3- (4-biphenyl)4-phenyl-5-tert-butylphenyl-1,2,4-triazole), spiro-PBD, BCP(2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline) and BAlq (bis(2-methyl-8-quinolinolate)-4-(phenylphenolato)aluminum).

An electron injection layer may be further disposed on the electron transport layer. The electron injection layer is an organic layer that facilitates injection of electrons from the cathode 446, and may be omitted depending on the structure and characteristics of the electroluminescence display device 400. The electron injection layer may be a metal inorganic compound such as BaF2, LiF, NaCl, CsF, _Li2O and BaO, and HAT-CN (dipyrazino[2,3-f:2',3'-h]quinoxaline-2, 3,6,7,10.11-hexacarbonitrile), CuPc (phthalocyanine), and NPD (N,N'-bis(naphthalene-1-yl)-N,N'-bis(phenyl)-2,2'-dimethylbenzidine) It may be any one or more organic compounds.

An electron blocking layer or hole blocking layer is further placed adjacent to the light emitting layer to block the flow of holes or electrons, so that when electrons are injected into the light emitting layer, they move from the light emitting layer and pass through the adjacent hole transport layer. When holes are injected into the light-emitting layer, the luminous efficiency can be improved by preventing the hole from moving from the light-emitting layer and passing through the adjacent electron transport layer.

The cathode 446 is disposed on the light emitting unit 444 and serves to supply electrons to the light emitting unit 444. Since the cathode 446 must supply electrons, it can be made of a metal material such as magnesium (Mg) or silver-magnesium (Ag:Mg), which is a conductive material with a low work function, but is not limited thereto.

When the electroluminescent display device 400 is a top emission type, the cathode 446 is made of indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), and zinc oxide ( It may be a transparent conductive oxide of the Zinc Oxide (ZnO) and Tin Oxide (TiO) series.

A bag is placed on the light emitting device 440 to prevent the thin film transistor 420 and the light emitting device 440, which are components of the electroluminescence display device 400, from being oxidized or damaged due to moisture, oxygen, or impurities flowing in from the outside. The portion 460 can be disposed and formed by stacking a plurality of encapsulation layers, a foreign matter compensation layer, and a plurality of barrier films.

The encapsulation layer is disposed on the entire upper surface of the thin film transistor 420 and the light emitting device 440, and may be composed of, but is not limited to, one of inorganic silicon nitride (SiNx) or aluminum oxide (AlyOz).

An encapsulation layer may be further disposed on the foreign matter compensation layer disposed on the encapsulation layer.

The foreign matter compensation layer is placed on the encapsulation layer, and can use organic silicon oxycarbon (SiOCz), acryl, or epoxy-based resin, but is not limited to this, and may be generated during the process. When defects occur due to cracks caused by foreign matter or particles, the bending and foreign matter can be covered by the foreign matter compensation layer to compensate.

By disposing a barrier film on the encapsulation layer and the foreign matter compensation layer, the electroluminescent display device 400 can delay the infiltration of oxygen and moisture from the outside. The barrier film is composed of a light-transmitting and double-sided adhesive film, and can be made of any one of the following insulating materials: Olefin-based, Acrylic-based, and Silicon-based, or COP (Cyclolefin). A barrier film made of any one of materials such as polymer), COC (cycloolefin copolymer), and PC (polycarbonate) can be further laminated, but is not limited thereto.

FIG. 4B is a cross-sectional view of the bending area (B/A) described in FIG. 3.

Some components of FIG. 4B are substantially the same/similar to the components described in FIG. 4A and detailed description thereof will be omitted.

The gate signal and data signal described in FIGS. 1 to 3 are transmitted from the outside to the pixels arranged in the display area (A/A) through circuit wiring arranged in the non-display area (N/A) of the flexible electroluminescent display device. and causes it to emit light.

When the wiring arranged in the non-display area (N/A) including the bending area (B/A) of the flexible electroluminescent display device is formed in a single layer structure, a large amount of space is required to place the wiring. After depositing a conductive material, the conductive material is patterned into the shape of the wire to be formed through a process such as etching. However, since the precision of the etching process is limited, a lot of space is required due to the limitation of narrowing the gap between wires. As the area of the non-display area (N/A) increases, difficulties may arise in implementing a narrow bezel.

Additionally, when one wire is used to transmit one signal, if the wire is cracked, the signal may not be transmitted. In the process of bending a flexible board, cracks may occur in the wiring itself or cracks may occur in other layers and the cracks may propagate to the wiring. Likewise, if a crack occurs in the wiring, the transmitted signal may not be transmitted.

Accordingly, the wiring disposed in the bending area (B/A) of the flexible electroluminescent display device according to the embodiment of the present specification is arranged in the form of a double wiring of the first wiring 462 and the second wiring 464.

The first wiring 462 and the second wiring 464 are made of a conductive material and may be made of a conductive material with excellent ductility to reduce the occurrence of cracks when bending the flexible substrate 410. For example, it can be formed of a conductive material with excellent ductility, such as gold (Au), silver (Ag), aluminum (Al), etc., and can be formed of one of various conductive materials used in the display area (A/A). , molybdenum (Mo), chromium (Cr), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu), and an alloy of silver (Ag) and magnesium (Mg). . Additionally, it may be composed of a multi-layer structure containing various conductive materials, for example, a three-layer structure of titanium (Ti)/aluminum (Al)/titanium (Ti), but is not limited thereto.

In order to protect the first wiring 462 and the second wiring 464, a buffer layer made of an inorganic insulating layer may be disposed under the first wiring 462 and the second wiring 464, and the first wiring 462 ) and a passivation layer made of an inorganic insulating layer is formed to surround the top and sides of the second wiring 464 to prevent phenomena such as corrosion of the first wiring 462 and the second wiring 464 by reacting with moisture, etc. It could be.

The first wiring 462 and the second wiring 464 formed in the bending area B/A are subjected to a tensile force when bent. As explained in FIG. 3, the wiring extending in the same direction as the bending direction on the flexible substrate 410 receives the greatest tensile force, and cracks may occur. If the cracks are severe, wire breakage may occur. Therefore, rather than forming the wiring to extend in the bending direction, at least a portion of the wiring arranged including the bending area (B/A) is formed to extend in a diagonal direction that is different from the bending direction, thereby minimizing the tensile force and cracking. occurrence can be reduced. The shape of the wiring may be a diamond shape, a triangular wave shape, a sinusoidal shape, a trapezoid shape, etc., but is not limited thereto.

A first wiring 462 is disposed on the flexible substrate 410 and a first planarization layer 435b is disposed on the first wiring 462. A second wiring 464 is disposed on the first planarization layer 435b, and a second planarization layer 437b is disposed on the second wiring 464.

The first planarization layer 435b and the second planarization layer 437b are made of acrylic resin, epoxy resin, phenolic resin, polyamides resin, and polyimide resin. (Polyimides Resin), Unsaturated Polyesters Resin, Polyphenylene Resin, Polyphenylenesulfides Resin, and Benzocyclobutene. may, but is not limited to this.

In addition, the first and second planarization layers 435a and 435b stacked on the display area (A/A) and the bending area (B/A), respectively, may be composed of the same layer.

A micro coating layer (Micro Coating Layer) 466 is disposed on the second planarization layer (437b). Since micro cracks may occur in the micro coating layer 466 due to tensile force acting on the wiring portion disposed on the flexible substrate 410 during bending, resin is coated with a thin layer at the bending position to secure the wiring. It can play a protective role.

The manufacturing process of the planarization layers 435a, 435b, 437a, and 437b disposed in the display area (A/A) and bending area (B/A) will be described with reference to FIGS. 6A to 6I.

Figure 5 is a cross-sectional view of a flexible electroluminescent display device according to an embodiment of the present specification.

Referring to FIG. 5, a barrier film 520 is disposed on the flexible substrate 510. The barrier film 520 is a component for protecting various components of the flexible electroluminescent display device 500, and may be arranged to correspond to at least the display area (A/A) of the flexible electroluminescent display device 500. Additionally, the barrier film 520 may be made of an adhesive material and may serve to fix the polarizing plate 530 on the barrier film 520.

A back plate 540 is disposed below the flexible substrate 510. When the flexible substrate 510 is made of a plastic material such as polyimide, the manufacturing process of the flexible electroluminescent display device 500 proceeds with a support substrate made of glass placed below the flexible substrate 510, and the manufacturing process proceeds. After completion, the support substrate can be separated and released.

Since components are needed to support the flexible substrate 510 even after the support substrate is released, a backplate 540 for supporting the flexible substrate 510 may be disposed below the flexible substrate 510. The backplate 540 may be disposed adjacent to the bending area (B/A) in other areas of the flexible substrate 510 other than the bending area (B/A).

Backplate 540 may be made of a plastic thin film formed of polyimide, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), other suitable polymers, or combinations of these polymers.

A support member 570 is disposed between the two back plates 540, and the support member 570 may be adhered to the back plate 540 by an adhesive layer 560. Support member 570 may be formed of a plastic material such as polycarbonate (PC), polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), other suitable polymers, combinations of these polymers, etc. . The strength of the support member 570 formed from these plastic materials may be controlled by providing additives to increase the thickness and strength of the support member 570. Additionally, the support member 570 may be formed of glass, ceramic, metal, or other rigid materials or a combination of the foregoing materials.

A micro coating layer (Micro Coating Layer) 550 is disposed on the bending area (B/A) of the flexible substrate 510. The micro coating layer 550 may be formed to cover one side of the barrier film 520. In addition, the micro coating layer 550 is coated with a thin layer of resin at the bending location because micro cracks may occur due to tensile force acting on the wiring portion disposed on the flexible substrate 510 during bending. It can play a role in protecting wiring.

An insulating film 580 is connected to the end of the flexible substrate 510. Various wirings are formed on the insulating film 580 to transmit signals to pixels arranged in the display area (A/A). The insulating film 580 is made of a material that has flexibility so that it can be bent. A driving element may be mounted on the insulating film 580, and together with the insulating film 650, it forms a driving package such as a chip on film (COF), and is formed on the insulating film 580. It is connected to the wiring and provides driving signals and data to the pixels placed in the display area (A/A).

The circuit board connected to the insulating film 580 can receive image signals from the outside and apply various signals to the pixels arranged in the display area (A/A), and may be a printed circuit board. .

6A to 6I are cross-sectional views of the manufacturing process of the display area (A/A) and bending area (B/A) of the flexible electroluminescence display according to an embodiment of the present specification.

The main components of the flexible electroluminescence display shown in FIGS. 6A to 6I may be substantially the same as or similar to the main components described in FIGS. 1 to 5.

Referring to FIG. 6A, a thin film transistor 620 is formed on the flexible substrate 610 in the display area (A/A), and a first wiring 662 is formed on the flexible substrate 610 in the bending area (B/A). ) to form.

A thin film transistor 620 including a gate electrode 622, a source electrode 624, a drain electrode 626, and a semiconductor layer 628 is formed on the flexible substrate 610 in the display area (A/A).

Additionally, a buffer layer may be further formed on the flexible substrate 610 to prevent penetration of moisture or other impurities and to flatten the surface of the flexible substrate 610.

The semiconductor layer 628 is formed by depositing one of amorphous silicon, polycrystalline silicon, or oxide semiconductor and patterning it with a mask. In addition, the semiconductor layer 628 may be formed to include a source region containing p-type or n-type impurities, a drain region, and a channel between the source region and the drain region, and between the channel and the adjacent source region and drain region. A low concentration doping area can be formed.

A gate insulating layer 631 composed of a single layer or multiple layers of silicon oxide (SiOx) or silicon nitride (SiNx) is deposited on the semiconductor layer 628.

The gate electrode 622 is made of conductive metals such as copper (Cu), aluminum (Al), molybdenum (Mo), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), and neodymium (Nd). It is formed by depositing a single layer or an alloy thereof and patterning it with a mask.

An interlayer insulating layer 633 composed of a single layer or multiple layers of silicon oxide (SiOx) or silicon nitride (SiNx) is deposited on the gate electrode 622.

The source electrode 624 and the drain electrode 626 are made of conductive metals such as copper (Cu), aluminum (Al), molybdenum (Mo), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), It is formed by depositing a single layer or multiple layers of a metal material such as neodymium (Nd) or an alloy thereof and patterning it with a mask.

A passivation film, which is an inorganic insulating layer such as silicon oxide (SiOx) or silicon nitride (SiNx), may be further formed on the thin film transistor 620.

6A to 6I illustrate a thin film transistor 620 having a coplanar structure, but it may also include a thin film transistor 620 having an inverted staggered structure.

A first wiring 662 is formed on the flexible substrate 610 in the bending area (B/A).

Additionally, as in the display area (A/A), a buffer layer may be further formed on the flexible substrate 610 to prevent moisture or other impurities from penetrating and to flatten the surface of the flexible substrate 610.

The first wiring 662 is made of a conductive material, and is made of conductive materials with excellent ductility, such as gold (Au), silver (Ag), aluminum (Al), etc., to reduce the occurrence of cracks when bending the flexible substrate 610. Likewise, it can be formed of a conductive material with excellent ductility, and can be formed of one of various conductive materials used in the display area (A/A), such as molybdenum (Mo), chromium (Cr), titanium (Ti), and nickel (Ni). ), neodymium (Nd), copper (Cu), and an alloy of silver (Ag) and magnesium (Mg). It may be composed of a multilayer structure containing various conductive materials. For example, the multilayer structure may be composed of a three-layer structure of titanium (Ti)/aluminum (Al)/titanium (Ti), deposited, and used as a mask. Formed by patterning.

In order to protect the first wiring 662, an inorganic insulating layer such as a passivation layer of the display area A/A may be further formed on the first wiring 662.

Referring to FIG. 6B, a first planarization layer 635a is formed on the thin film transistor 620 in the display area (A/A), and the flexible substrate 610 and the first wiring ( A first planarization layer 635b is formed on 662).

The first planarization layer 635a of the display area (A/A) and the first planarization layer 635b of the bending area (B/A) are made of acrylic resin, epoxy resin, and phenolic resin, respectively. Phenolic Resin, Polyamides Resin, Polyimides Resin, Unsaturated Polyesters Resin, Polyphenylene Resin, Polyphenylenesulfides Resin, and benzocyclobutene can be formed in the same layer with one or more materials.

Referring to FIG. 6C, a first mask 670 is spaced a certain distance apart on the first flattening layer 635a of the display area (A/A) and the first flattening layer 635b of the bending area (B/A). Place and proceed with exposure.

Additionally, the first mask 670 may use a half-tone mask. The halftone mask is a mask having a light blocking part 672, a transparent part 674, and a semi-transmissive part 676. The light blocking part 672 is a part that blocks light, and the transparent part 674 is a part that transmits light, The semi-transmissive portion 676 refers to a portion in which the light transmission amount is smaller than that of the light transmitting portion. When using a halftone mask, patterns with different heights can be formed simultaneously by differentially irradiating the amount of light during exposure.

The first mask 670 to which the halftone mask is applied is spaced a certain distance apart on the first flattening layer 635a of the display area (A/A) and the first flattening layer 635b of the bending area (B/A). They are arranged so that light with different irradiation amounts is irradiated onto the first planarization layers 635a and 635b.

Referring to FIG. 6D, a contact hole (C/H) exposing the top surface of the drain electrode 626 is formed in the first planarization layer 635a of the display area (A/A), and a bending area (B) is formed. The thickness of the first planarization layer 635b in /A) is smaller than the thickness of the first planarization layer 635a in the display area A/A.

Additionally, the thickness of the first planarization layer 635b in the decreasing bending area B/A may be set according to the characteristics of the flexible electroluminescent display device, and is not limited to this thickness value.

Referring to Figure 6e, an intermediate electrode 630 is formed in the contact hole (C/H) formed in the first planarization layer 635a of the display area (A/A) and connected to the thin film transistor 620 disposed below. , and the second wiring 664 is formed on the first planarization layer 635b in the bending area B/A.

Additionally, a buffer layer may be further formed on the first planarization layer 635a of the display area (A/A) and the first planarization layer 635b of the bending area (B/A).

The buffer layer is disposed to protect the components placed on the buffer layer, and may be composed of a single layer of silicon nitride (SiNx) or silicon oxide (SiOx) or multiple layers of silicon nitride (SiNx) or silicon oxide (SiOx). , can also be omitted.

The intermediate electrode 630 is connected to the thin film transistor 620 through the contact hole (C/H) formed in the first planarization layer 635a.

A passivation layer made of an inorganic insulating layer such as silicon oxide (SiOx) or silicon nitride (SiNx) may be further disposed on the first planarization layer 635a and the intermediate electrode 630. The passivation layer may serve to prevent unnecessary electrical connections between passivation layer components and prevent contamination or damage from the outside, and may be omitted.

The second wiring 664 is formed on the first flattening layer 635b of the bending area B/A by arranging the second wiring 664 in the form of a double wiring at a position that does not overlap the first wiring 662.

The second wiring 664 is made of a conductive material and may be made of a conductive material with excellent ductility to reduce the occurrence of cracks when bending the flexible substrate 610. For example, it can be formed of a conductive material with excellent ductility, such as gold (Au), silver (Ag), aluminum (Al), etc., and can be formed of one of various conductive materials used in the display area (A/A). , molybdenum (Mo), chromium (Cr), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu), and an alloy of silver (Ag) and magnesium (Mg). . Additionally, it may be composed of a multi-layer structure containing various conductive materials, for example, a three-layer structure of titanium (Ti)/aluminum (Al)/titanium (Ti), but is not limited thereto.

As in the display area (A/A), a buffer layer made of an inorganic material may be disposed under the second wiring 664, and may be placed to surround the top and sides of the first wiring 462 and the second wiring 464. A passivation layer made of an inorganic material may be formed, but is not limited thereto.

The first wiring 462 and the second wiring 464 formed in the bending area B/A are subjected to a tensile force when bent. As explained in FIG. 3, the wiring extending in the same direction as the bending direction on the flexible substrate 410 receives the greatest tensile force, and cracks may occur. If the cracks are severe, wire breakage may occur. Therefore, rather than forming the wiring to extend in the bending direction, at least a portion of the wiring arranged including the bending area (B/A) is formed to extend in a diagonal direction that is different from the bending direction, thereby minimizing the tensile force and cracking. occurrence can be reduced. The shape of the wiring may be a diamond shape, a triangular wave shape, a sinusoidal shape, a trapezoid shape, etc., but is not limited thereto.

Referring to FIG. 6F, as described in FIGS. 6C and 6D, a second planarization layer 637a is formed on the first planarization layer 635a and the intermediate electrode 630 in the display area A/A, A second planarization layer 637b is formed on the first planarization layer 635b and the first wiring 662 in the bending area (B/A), and the second planarization layer 637b is formed in the display area (A/A). And a second mask 671 is placed at a certain distance apart on the second planarization layer 637b in the bending area (B/A), and exposure is performed. Additionally, the second mask 671 may be used by applying a halftone mask.

As described in FIGS. 6C and 6D, the second planarization layer 637a of the display area (A/A) and the second planarization layer 637b of the bending area (B/A) are each made of acrylic resin, Epoxy Resin, Phenolic Resin, Polyamides Resin, Polyimides Resin, Unsaturated Polyesters Resin, Polyphenylene Resin ), polyphenylenesulfides resin, and benzocyclobutene may be formed in the same layer.

Additionally, through the exposure process, the thickness of the second planarization layer 637b in the bending area (B/A) becomes smaller than the thickness of the second planarization layer (637a) in the display area (A/A).

Additionally, the thickness of the second planarization layer 637b in the decreasing bending area (B/A) can be set according to the characteristics of the flexible electroluminescent display device, and is not limited to this thickness value.

Referring to FIG. 6G, as described in FIG. 6D, a contact hole (C/H) exposing the upper surface of the intermediate electrode 630 is formed in the second planarization layer 637a of the display area (A/A).

Referring to FIG. 6H, the light emitting device 640 is formed on the second planarization layer 637a in the display area (A/A). And, the light emitting device 640 is connected to the thin film transistor 620 disposed below through the intermediate electrode 630 through the contact hole (C/H) formed in the second planarization layer 637a.

The light emitting device 640 formed on the second planarization layer 637a includes an anode 642, a light emitting portion 644, and a cathode 646.

The anode 642 is deposited with transparent conductive materials such as indium tin oxide (ITO) and indium zinc oxide (IZO). If a reflective layer is included, silver (Ag) or an alloy containing silver is further deposited and patterned with a mask. form

The light emitting portion 644 is deposited between the anode 642 and the cathode 646 using a deposition mask, FMM (Fine Metal Mask). The light emitting part 644 is formed by depositing a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer on the anode 642, and some components of the light emitting part 644 may be omitted. Here, it may be composed of at least one layer among a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.

The cathode 646 is formed by depositing a metal material such as magnesium (Mg) or silver-magnesium (Ag:Mg), which is a conductive material with a low work function, on the light emitting portion 644.

Referring to FIG. 6I, a micro coating layer 666 is formed on the second planarization layer 637b in the bending area (B/A).

The micro coating layer 666 protects the wiring by coating it with a thin layer of resin at the bending position because tension may occur on the wiring portion disposed on the flexible substrate 610 during bending, which may cause fine cracks. The thickness of the micro coating layer 666 considers the position of the neutral plane of the bending area (B/A), and the thickness can be set according to the characteristics of the flexible electroluminescent display device, and is limited to this thickness value. It doesn't work.

FIGS. 7A and 7B are cross-sectional views showing changes in the neutral plane according to the thickness of the planarization layer of the bending area (B/A) of the flexible electroluminescent display device according to an embodiment of the present specification.

The main components of the flexible electroluminescence display shown in FIGS. 7A and 7B are substantially the same as or similar to the main components described in FIGS. 1 to 6I.

Referring to FIG. 7A, the thickness of the first planarization layer 635b and the second planarization layer 637b is the same as the first planarization layer 635a and the second planarization layer 637a in the display area (A/A). , and a micro coating layer 666 is deposited on the second planarization layer 637b.

Neutral Plane (N/P) refers to an imaginary plane that is not stressed when a structure is bent because the compressive force and tensile force applied to the structure cancel each other out. When bending, the layer placed on the upper surface relative to the neutral plane is stretched and receives a tensile force, and the layer placed on the lower surface is compressed and thus receives a compressive force.

Since the inorganic or organic material constituting the insulating layer itself has the characteristic of brittleness, the insulating layer including the planarization layer has significantly lower flexibility compared to wiring made of metal. Therefore, when bending a substrate with an insulating layer formed on it, cracks may occur in the insulating layer due to the tensile force caused by bending. Since it is more vulnerable when subjected to a tensile force among compressive and tensile forces of the same size, it is not subjected to the tensile force or is subjected to the tensile force. However, it is very important to optimize the neutral plane to minimize the magnitude of the force.

As shown in FIG. 7A, the first planarization layer 635b and the second planarization layer 637b are deposited to the same thickness as the first planarization layer 635a and the second planarization layer 637a in the display area (A/A). Otherwise, the neutral plane (N/P) may be located in the planarization layer, and in order to prevent this, there is a disadvantage in optimizing the neutral plane (N/P) by depositing a micro coating layer 666 with a thickness larger than necessary.

Referring to FIG. 7B, the thickness of the first planarization layer 635b and the second planarization layer 637b is smaller than the first planarization layer 635a and the second planarization layer 637a in the display area (A/A). When deposited, the thickness of the micro coating layer 666 is appropriately adjusted and the neutral plane (N/P) is located on the micro coating layer 666, thereby preventing cracks that may occur in the planarization layer.

The flexible electric field display device according to an embodiment of the present specification adjusts the thickness of the flattening layer in the bending area (B/A) to optimize the neutral plane (N/P) of the bending area (B/A) to prevent defects caused by cracks. can be minimized.

A flexible electroluminescent display device according to an embodiment of the present invention includes a flexible substrate including a display area and a bending area extending from one side of the display area, a thin film transistor and a light emitting element in the display area, and a display area and a bending area, respectively. It includes a first planarization layer and a second planarization layer, a first wire and a second wire in the bending area, and the sum of the thicknesses of the first planarization layer and the second planarization layer in the display area is 1 greater than the sum of the thicknesses of the planarization layer and the second planarization layer.

In the flexible electroluminescent display device according to an embodiment of the present invention, the first and second wires in the bending area include one of a rhombus shape, a triangular wave shape, a sinusoidal wave shape, and a trapezoid shape.

The flexible electroluminescent display device according to an embodiment of the present invention further includes a buffer layer below the first or second wiring.

The first or second wiring of the flexible electroluminescent display device according to an embodiment of the present invention is composed of a plurality of metal layers.

The flexible electroluminescent display device according to an embodiment of the present invention further includes an insulating film connected to the flexible substrate and a driving element disposed on the insulating film.

The first planarization layer and the second planarization layer of the flexible electroluminescent display device according to an embodiment of the present invention are composed of organic materials.

The flexible electroluminescent display device according to claim 1 further includes a micro cover layer disposed on the second planarization layer in the bending area.

The neutral plane of the bending area of the flexible electroluminescence display according to an embodiment of the present invention is on the micro cover layer.

A flexible electroluminescent display device according to an embodiment of the present invention includes the steps of forming a flexible substrate including a display area and a bending area extending from one side of the display area, forming a thin film transistor and a light emitting element in the display area, and bending. Forming a first wiring in the region, forming a first planarization layer on the thin film transistor and light emitting device in the display region, and the flexible substrate and first wiring in the bending region, using a halftone mask to form a first planarization layer in the bending region. 1 Reducing the thickness of the planarization layer, forming a second wiring on the first planarization layer in the bending area, forming a second wiring on the first planarization layer in the display area and the first planarization layer and the second wiring in the bending area. Forming a flattening layer, reducing the thickness of the second flattening layer in the bending area using a halftone mask, forming a micro cover layer on the second flattening layer in the bending area, and bending the bending area. It is manufactured so that the sum of the thicknesses of the first and second planarization layers in the bending area is smaller than the sum of the thicknesses of the first and second planarization layers in the display area.

The first and second wires in the bending area of the flexible electroluminescent display device according to an embodiment of the present invention are manufactured to include one of a rhombus shape, a triangular wave shape, a sinusoidal shape, and a trapezoid shape.

The first or second wiring of the flexible electroluminescent display device according to an embodiment of the present invention is manufactured by consisting of a plurality of metal layers.

The manufacturing method further includes forming a buffer layer under the first or second wiring of the flexible electroluminescence display according to an embodiment of the present invention.

The flexible electroluminescent display device according to an embodiment of the present invention further includes forming a contact hole in the first planarization layer and forming an intermediate electrode in the contact hole, and forming a thin film transistor and a light emitting element in the display area into the first planarization layer. It is manufactured to connect the thin film transistor and light emitting device of the display area through the intermediate electrode in the contact hole formed in the planarization layer.

The step of reducing the thickness of the first planarization layer in the bending area of the flexible electroluminescence display according to an embodiment of the present invention is performed simultaneously with the step of forming a contact hole in the first planarization layer.

The flexible electroluminescent display device according to an embodiment of the present invention further includes forming a contact hole in the second planarization layer, and is manufactured to connect the intermediate electrode of the display area and the thin film transistor through the contact hole in the second planarization layer. do.

The step of reducing the thickness of the second planarization layer in the bending area of the flexible electroluminescent display device according to an embodiment of the present invention is performed simultaneously with the step of forming a contact hole in the second planarization layer.

The neutral plane of the bending area of the flexible electroluminescent display device according to an embodiment of the present invention is manufactured so that it is in the micro cover layer.

A flexible electroluminescent display device according to an embodiment of the present invention includes a flexible substrate including a display area and a non-display area surrounding the display area and having a bending area, a thin film transistor and a light emitting element in the display area, a display area, and It includes a plurality of planarization layers in the non-display area including the bending area, wiring on each of the flexible substrate and the planarization layer, and a micro cover layer on the planarization layer in the bending area, and the neutral plane of the bending area is on the micro cover layer. It is in

The thickness of the planarization layer on the display area of the flexible electroluminescent display device according to the embodiment of the present invention is different from the thickness of the planarization layer on the bending area.

The wiring on the flexible substrate and the planarization layer in the bending area of the flexible electroluminescent display device according to an embodiment of the present invention includes one of a rhombus shape, a triangular wave shape, a sinusoidal wave shape, and a trapezoid shape.

Although embodiments of the present invention have been described in more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be made without departing from the technical spirit of the present invention. . Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are for illustrative purposes, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. The scope of protection of the present invention should be interpreted in accordance with the claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of rights of the present invention.

100, 200, 300, 400, 500, 600: Electroluminescent display device
110: Image processing unit 120: Timing controller
130: data driver 140: gate driver
150: display panel
160: Pixels
220: Gateline
230: data line
240: switching transistor 250: driving transistor
260: Compensation circuit
270, 440, 640: Light emitting device
310, 410, 510, 610: substrate
320: Circuit wiring
420, 620: thin film transistor 422, 622: gate electrode
424, 624: source electrode 426, 626: drain electrode
428, 628: semiconductor layer 431, 631: gate insulating layer
433, 633: Interlayer insulation layer
435a, 435b, 635a, 635b,: first planarization layer
437a, 437b, 637a, 637b: second planarization layer
442, 642: anode 444, 644: light emitting unit
446, 646: cathode
450, 650: Bank 452: Spacer
460: Encapsulation part
462, 662: first wiring
464, 664: second wiring
466, 666: micro cover layer
520: barrier film 530: polarizer
540: backplate
550, 670: Micro coating layer
560: Adhesive layer 570: Support member
580: circuit board
670: first mask 671: second mask
672: light-shielding part 674: transmitting part
676: Semi-transparent part
A/A: Display area N/A: Non-display area
B/A: Bending area N/P: Neutral plane

Claims (19)

A flexible substrate including a display area and a bending area extending from one side of the display area and being bent.
a thin film transistor disposed on the flexible substrate in the display area and consisting of a semiconductor layer, a gate electrode, a source electrode, and a drain electrode;
a first insulating layer disposed on the thin film transistor in the display area, and a second insulating layer disposed on the first insulating layer;
a light emitting element connected to the thin film transistor on the second insulating layer in the display area and consisting of an anode, a light emitting unit, and a cathode; and
In the bending area, a first wiring on the flexible substrate, a third insulating layer on the first wiring, a second wiring on the third insulating layer, and a fourth insulating layer on the second wiring,
The first wiring and the second wiring have a multi-layer structure,
The first wire and the second wire are arranged parallel to each other,
Further comprising an intermediate electrode between the thin film transistor and the anode,
The display device wherein the second wiring is made of the same layer as the intermediate electrode. delete According to paragraph 1,
The first wiring and the second wiring overlap at least in part. According to paragraph 1,
The first wiring and the second wiring each include a three-layer structure of titanium (Ti)/aluminum (Al)/titanium (Ti). According to paragraph 1,
A display device wherein a thickness of the third insulating layer is smaller than a thickness of the first insulating layer. According to paragraph 1,
A display device wherein a thickness of the fourth insulating layer is smaller than a thickness of the second insulating layer. According to paragraph 1,
The display device wherein the sum of the thicknesses of the first insulating layer and the second insulating layer is greater than the sum of the thicknesses of the third insulating layer and the fourth insulating layer. According to paragraph 1,
The first insulating layer, the second insulating layer, the third insulating layer, and the fourth insulating layer are each made of an acrylic resin, an epoxy resin, a phenolic resin, a polyamide-based resin, a polyimide-based resin, an unsaturated polyester-based resin, A display device formed of at least one of polyphenyline-based resin, polyphenylene sulfide-based resin, and benzocyclobutene. delete According to paragraph 1,
The thin film transistor includes a structure in which a gate insulating layer on the semiconductor layer, a gate electrode on the gate insulating layer, an interlayer insulating layer on the gate electrode, and the source electrode and the drain electrode on the interlayer insulating layer are stacked. Device. According to paragraph 1,
The display device wherein the source electrode and the drain electrode each include the same material as the first wiring or the second wiring. According to paragraph 1,
The display device wherein the source electrode and the drain electrode each include a three-layer structure of titanium (Ti)/aluminum (Al)/titanium (Ti). According to paragraph 1,
A display device in which the thin film transistor and the anode are electrically connected. delete According to clause 13,
The display device further includes a bank disposed on the anode and covering at least a portion of the anode. According to clause 15,
A display device further comprising a spacer on the bank. According to paragraph 1,
Further comprising a cover layer on the fourth insulating layer disposed in the bending area,
A display device wherein the neutral plane of the bending area is on the cover layer. According to paragraph 1,
The first wiring and the second wiring in the bending area include one of a diamond shape, a triangular wave shape, a sinusoidal wave shape, and a trapezoid shape. According to paragraph 1,
The display device wherein the first wiring and the second wiring are arranged parallel to each other at positions that do not overlap each other.