Flexible display device

Abstract

A flexible display device according to an exemplary embodiment of the present disclosure may include: a substrate divided into a display area and a non-display area; a first buffer layer disposed above the substrate; a second buffer layer disposed below the substrate; a supporting member disposed below the second buffer layer; a transistor and a light emitting element disposed above the first buffer layer in the display area; a conductive layer disposed in the second buffer layer in the non-display area; and a connecting member disposed on the first buffer layer in the non-display area and electrically connected to the conductive layer through a contact hole, thereby providing an effect of minimizing uneven brightness of a display panel due to the use of a polyimide (PI) substrate by grounding and removing charges accumulated in the PI substrate.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority of Korean Patent Application No. 10-2019-0139419 filed on November 4, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a flexible display device, and more particularly, to a flexible display device using a flexible substrate. Background Art

[0004] Recently, as society develops toward an information society, the field of display devices for visually expressing electrical information signals has rapidly developed, and various display devices having excellent performance in terms of reduced thickness, weight, and low power consumption have been developed accordingly.

[0005] Representative display devices may include a liquid crystal display device (LCD), a field emission display device (FED), an electrowetting display device (EWD), an organic light emitting display device (OLED), and the like.

[0006] Unlike liquid crystal display devices having a separate light source, electroluminescent display devices represented by organic light-emitting display devices are self-luminous display devices, and since they do not require a separate light source, they can be manufactured to be thin and light. In addition, electroluminescent display devices have advantages in power consumption due to low voltage driving, and are excellent in color realization, response speed, viewing angle, and contrast (CR). Therefore, it is expected that electroluminescent display devices will be used in various fields.

[0007] In an electroluminescent display device, a light-emitting layer (EML) is provided between two electrodes formed by 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.

[0008] The host material and the dopant material are included in the light-emitting layer and interact with each other. The host generates excitons from electrons and holes and transfers energy to the dopant. The dopant is a dye-based organic material added in small amounts and receives energy from the host to convert it into light.

[0009] The electroluminescent display device is encapsulated with glass, metal or film to block moisture or oxygen from being introduced into the interior of the electroluminescent display device from the outside, thereby preventing oxidation of the light-emitting layer or the electrode and protecting it from external mechanical or physical impact.

[0010] Meanwhile, recently, a flexible display device manufactured to be able to display an image even when the display device is rolled by forming a display element, a circuit, etc. on a flexible substrate (eg, plastic of a flexible material) has received widespread attention as a next-generation display device. Summary of the invention

[0011] An object to be achieved by the present disclosure is to provide a flexible display device in which uneven brightness due to the use of a polyimide (PI) substrate is minimized.

[0012] The objects of the present disclosure are not limited to the above objects, and other objects not mentioned above can be clearly understood by those skilled in the art from the following description.

[0013] According to one aspect of the present disclosure, a flexible display device may include: a substrate divided into a display area and a non-display area; a first buffer layer disposed above the substrate; a second buffer layer disposed below the substrate; a supporting member disposed below the second buffer layer; a transistor and a light-emitting element disposed above the first buffer layer in the display area; a conductive layer disposed in the second buffer layer in the non-display area; and a connecting member disposed on the first buffer layer in the non-display area and electrically connected to the conductive layer through a contact hole.

[0014] According to another aspect of the present disclosure, a flexible display device may include: a substrate divided into a display area and a non-display area; a first buffer layer disposed above the substrate; a second buffer layer disposed below the substrate; a support member disposed below the second buffer layer; a transistor and a light-emitting element disposed above the first buffer layer in the display area; a conductive layer disposed in the second buffer layer in the non-display area; and a connecting member connected to the conductive layer through a contact hole, wherein the substrate is made of polyimide, and the connecting member removes charges accumulated in the polyimide substrate by grounding.

[0015] Additional details of example embodiments are included in the detailed description and the accompanying drawings.

[0016] The flexible display device according to the exemplary embodiment of the present disclosure provides an effect of minimizing uneven brightness of a display panel due to the use of a polyimide (PI) substrate by grounding and removing charges accumulated in the PI substrate.

[0017] The effects according to the present disclosure are not limited to the contents exemplified above, and more various effects are included in the present specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other aspects, features and other advantages of the present disclosure will be more clearly understood through the following detailed description in conjunction with the accompanying drawings, in which:

[0019] Figure 1 is a block diagram of a flexible display device according to a first exemplary embodiment of the present disclosure;

[0020] Figure 2 is a circuit diagram of a sub-pixel included in a flexible display device according to a first exemplary embodiment of the present disclosure;

[0021] Figure 3 is a plan view of a flexible display device according to a first exemplary embodiment of the present disclosure;

[0022] Figure 4 is along Figure 3 A cross-sectional view taken along line II';

[0023] Figure 5 is along Figure 3 A cross-sectional view taken along line II-II';

[0024] Figure 6 is a cross-sectional view illustrating a portion of a non-display area in a flexible display device according to a second exemplary embodiment of the present disclosure;

[0025] Figure 7 is a cross-sectional view illustrating a portion of a display area in a flexible display device according to a third exemplary embodiment of the present disclosure;

[0026] Figure 8 is a cross-sectional view illustrating a portion of a non-display area in a flexible display device according to a third exemplary embodiment of the present disclosure;

[0027] Fig. 9 is a cross-sectional view illustrating a portion of a non-display area in a flexible display device according to a fourth exemplary embodiment of the present disclosure;

[0028] Fig.10 is a plan view of a flexible display device according to a fifth exemplary embodiment of the present disclosure;

[0029] Fig.11 is along Fig.10 A cross-sectional view taken along line III-III';

[0030] Fig.12 is a plan view of a flexible display device according to a sixth exemplary embodiment of the present disclosure;

[0031] Fig.13 It is along Fig.12 A cross-sectional view taken along line IV-IV'; and

[0032] Fig.14A and Fig. 14Bis a perspective view of a flexible display device according to the present disclosure. DETAILED DESCRIPTION

[0033] By referring to the exemplary embodiments described in detail below and the accompanying drawings, the advantages and features of the present disclosure and the methods for achieving the advantages and features will become clear. However, the present disclosure is not limited to the exemplary embodiments disclosed herein, but will be implemented in various forms. Exemplary embodiments are provided only by way of example so that those skilled in the art can fully understand the present disclosure and the scope of the present disclosure. Therefore, the present disclosure is limited only by the scope of the appended claims.

[0034] The shapes, sizes, ratios, angles, quantities, etc. shown in the accompanying drawings for describing the exemplary embodiments of the present disclosure are merely examples, and the present disclosure is not limited thereto. Throughout the specification, the same reference numerals generally represent the same elements. In addition, in the following description of the present disclosure, a detailed description of known related technologies may be omitted to avoid making the subject matter of the present disclosure unclear unnecessarily. Terms such as "including", "having" and "consisting of..." used herein are generally intended to allow the addition of other components unless the term is used together with the term "only". Unless otherwise expressly stated, any reference to the singular may include the plural.

[0035] Even if not explicitly stated, the components are interpreted as including ordinary error ranges.

[0036] When terms such as “on,” “above,” “below,” and “next” are used to describe the positional relationship between two components, one or more components may be located between the two components unless terms with “immediately” or “directly” are used.

[0037] When an element or layer is disposed “on” another element or layer, other layers or other elements may be interposed therebetween.

[0038] Although the terms "first", "second", etc. are used to describe various components, these components are not limited to these terms. These terms are only used to distinguish one component from other components. Therefore, in the technical concept of the present disclosure, the first component to be mentioned below may be the second component.

[0039] Throughout the specification, like reference numerals generally refer to like elements.

[0040] For convenience of description, the size and thickness of each component shown in the drawings are shown, and the present disclosure is not limited to the size and thickness of the components shown.

[0041] The features of the various embodiments of the present disclosure may be partially or completely joined or combined with each other, and may be interlocked and operated in technically various ways, and these embodiments may be performed independently or in association with each other.

[0042] Hereinafter, a flexible display device according to exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0043] Figure 1 is a block diagram of a flexible display device according to a first exemplary embodiment of the present disclosure.

[0044] refer to Figure 1 , the flexible display device 100 according to the first exemplary embodiment of the present disclosure may include an image processor 151 , a timing controller 152 , a data driver 153 , a gate driver 154 , and a display panel 150 .

[0045] The image processor 151 may output a data signal DATA and a data enable signal DE through a data signal DATA provided from the outside.

[0046] The image processor 151 may output one or more of a vertical synchronization signal, a horizontal synchronization signal, and a clock signal in addition to the data enable signal DE.

[0047] The timing controller 152 receives a data enable signal DE or a data signal DATA, and driving signals including a vertical synchronization signal, a horizontal synchronization signal, a clock signal, etc. from the image processor 151. The timing controller 152 may output a gate timing control signal GDC for controlling the operation timing of the gate driver 154 and a data timing control signal DDC for controlling the operation timing of the data driver 153 based on the driving signal.

[0048] The data driver 153 samples and latches the data signal DATA provided from the timing controller 152 in response to the data timing control signal DDC provided from the timing controller 152, and converts the data signal DATA into a gamma reference voltage to output it. The data driver 153 may output the data signal DATA through the data lines DL1 to DLn.

[0049] The gate driver 154 may output a gate signal while changing a level of a gate voltage in response to the gate timing control signal GDC provided from the timing controller 152 .

[0050] The gate driver 154 may output gate signals through the gate lines GL1 to GLm.

[0051] In response to the data signal DATA and the gate signal provided from the data driver 153 and the gate driver 154, the display panel 150 may display an image when the sub-pixel P emits light. The detailed structure of the sub-pixel P will be described in detail in Figure 2 and Figure 4 Described in detail in.

[0052] Figure 2 is a circuit diagram of a sub-pixel included in the flexible display device according to the first exemplary embodiment of the present disclosure.

[0053] refer to Figure 2 , the sub-pixel P of the flexible display device 100 according to the first exemplary embodiment of the present disclosure may include a switching transistor ST, a driving transistor DT, a compensation circuit 135 , and a light emitting element 130 .

[0054] The light emitting element 130 may be operated to emit light according to a driving current formed by the driving transistor DT.

[0055] The switching transistor ST may perform a switching operation in response to a gate signal provided through the gate line 116 so that a data signal provided through the data line 117 is stored in the capacitor as a data voltage.

[0056] The driving transistor DT may operate in response to the data voltage stored in the capacitor so that a constant driving current flows between the high potential power line VDD and the low potential power line GND.

[0057] The compensation circuit 135 is a circuit for compensating for a threshold voltage of the driving transistor DT, etc., and the compensation circuit 135 may include one or more transistors and capacitors. The configuration of the compensation circuit 135 may vary according to a compensation method.

[0058] For example, Figure 2 The sub-pixel shown is configured to have a 2T (transistor) 1C (capacitor) structure including a switching transistor ST, a driving transistor DT, a capacitor, and a light emitting element 130. However, when a compensation circuit 135 is added, the sub-pixel may have various structures such as 3T1C, 4T2C, 5T2C, 6T1C, 6T2C, 7T1C, 7T2C, etc.

[0059] At the same time, the present disclosure is characterized in that a doping layer (or conductive layer) is formed in a lower buffer layer in an edge area of ​​a display panel, and the doping layer is connected to a low potential power line GND through a contact hole to remove charges accumulated in a polyimide (PI) flexible substrate in an edge area of ​​the display panel.

[0060] A rollable display device and a flexible display device such as a bezel bendable display device with a curved bezel area may use polyimide as a flexible substrate.

[0061] Rollable display devices may refer to display devices that can display images even when they are rolled.

[0062] In the case of a flexible display device using polyimide as a flexible substrate, when a positive bias stress is applied to a transistor, a large amount of charge accumulates in the polyimide substrate, which affects the driving of the display panel. That is, when a positive bias stress is applied to the gate of the transistor, negative charge accumulates in the channel region, and positive charge accumulates in the polyimide substrate under the transistor. When the display panel is driven, the charge accumulates in the edge region of the display panel due to the different configurations of the transistors in the GIP circuit unit and the display region.

[0063] Therefore, a brightness defect occurs in which brightness increases along an edge region of the display panel.

[0064] Therefore, the present disclosure is characterized in that, in the edge area of ​​the display panel, a portion of the second buffer layer under the polyimide substrate is doped (a portion of the second buffer layer is made conductive) to form a doped layer (or conductive layer) as a discharge area, and the doped layer is connected (grounded) to a low potential power line (GND) through a contact hole, thereby minimizing the brightness unevenness of the display panel caused by using the polyimide substrate.

[0065] Figure 3 is a plan view of a flexible display device according to a first exemplary embodiment of the present disclosure.

[0066] Figure 4 is along Figure 3 A cross-sectional view taken along line II'.

[0067] Figure 5 is along Figure 3 A cross-sectional view taken along line II-II'.

[0068] Figure 4 It is shown Figure 3 A cross-sectional view of the detailed structure of the display area shown, Figure 5 It is shown Figure 3 A cross-sectional view showing the detailed structure of the non-display area.

[0069] refer to Figure 3 , the flexible display device 100 according to the first exemplary embodiment of the present disclosure includes a display area AA and a non-display area.

[0070] For convenience, the non-display area may be defined as an area other than the display area AA, and description of reference numerals thereof will be omitted.

[0071] The display area AA may be disposed at the center of the display panel, and may be an area where an image is displayed in the flexible display device 100 .

[0072] The display element and various driving elements for driving the display element may be arranged in the display area AA. For example, the display element may be composed of a light-emitting element including a first electrode, a light-emitting layer, and a second electrode, which will be described later. In addition, various driving elements such as transistors, capacitors, and circuits for driving the display element may be arranged in the display area AA.

[0073] The display area AA may include a plurality of sub-pixels PX.

[0074] The sub-pixel PX is the smallest unit constituting the screen, and each of the plurality of sub-pixels PX may include a light-emitting element and a driving element. In addition, the driving element may include a switching transistor, a driving transistor, etc. The driving element may be electrically connected to a signal line, such as a gate line and a data line, and the signal line is connected to a gate driver, a data driver, etc. disposed in a non-display area. Figure 4 A more detailed structure of the sub-pixel PX is described.

[0075] A plurality of sub-pixels PX may be defined as intersections of a plurality of gate lines arranged along a first direction and a plurality of data lines arranged along a second direction different from the first direction. Figure 3 The second direction can be Figure 3 The plurality of sub-pixels PX may include red sub-pixels, green sub-pixels, blue sub-pixels, and white sub-pixels that emit light of different wavelengths, but are not limited thereto.

[0076] The non-display area corresponds to the edge area of ​​the display panel and may be an area where no image is displayed. The non-display area may be arranged to surround the display area AA. Various components for driving a plurality of sub-pixels PX arranged in the display area AA may be arranged in the non-display area. For example, a driver IC, a drive circuit, a signal line, a flexible film, etc. that provide signals for driving a plurality of sub-pixels PX may be arranged in the non-display area. In this case, the driver IC may include a gate driver, a data driver, etc. The gate driver and the data driver may be implemented as transistors. The driver IC and the drive circuit may be arranged in a GIP (gate in panel) manner, a COF (chip on film) manner, a TAB (tape automated bonding) manner, a TCP (tape carrier package) manner, or a COG (chip on glass) manner, or may be integrated in the display panel.

[0077] The non-display area includes a pad area. For example, the pad area may be provided at the lower end of the display panel. The pad area may include a plurality of pads 155 and signal lines connected to the plurality of pads 155. A driver IC, a driving circuit or a flexible film may be connected to the pad area through the plurality of pads 155. The driver IC, the driving circuit or the flexible film may transmit various driving signals, low potential voltages and high potential voltages to the plurality of pads 155.

[0078] The plurality of pads 155 receive various driving signals for driving the flexible display device 100 and provide them to components of the flexible display device 100 , such as a plurality of sub-pixels PX, so that the flexible display device 100 may be driven.

[0079] The plurality of pads 155 include: a data pad for providing a data signal to each of the plurality of sub-pixels PX; a high potential power pad for providing a high potential voltage to the first electrode of the light emitting element; and a low potential power pad for providing a low potential voltage to the second electrode of the light emitting element.

[0080] For example, the low potential power pads may be provided one by one at both ends of the plurality of pads 155. The low potential power line may be electrically connected to the low potential power pads. In this case, the low potential power line may be a first power line. The second electrode of the light emitting element may be electrically connected to the low potential power line. Therefore, the low potential power line may supply a low potential voltage to the second electrode.

[0081] In addition, the connection line 126 may be electrically connected to the low potential power pad. The connection line 126 may be electrically connected to the doping layer (or conductive layer) 145 of the lower buffer layer. That is, the connection line 126 may be electrically connected to the doping layer 145 of the lower buffer layer through the plurality of contact holes 140 while being connected (or grounded) to the low potential power line, so that the charges accumulated in the polyimide substrate may be removed.

[0082] The connection line 126 may be connected to the pad 155 , ie, the low potential power supply pad, in a quadrangular frame shape.

[0083] The connection line 126 may be formed of a metal material having high conductivity. The connection line 126 may be formed of a light shielding pattern of the display area AA, an electrode of a transistor, or a first electrode or a second electrode of a light emitting element.

[0084] In order to improve the brightness defect in the edge area of ​​the display panel due to the charging of the polyimide substrate, a doping layer (or conductive layer) 145 having a quadrilateral frame shape may be formed in the second buffer layer under the polyimide substrate. However, the present disclosure is not limited thereto, and the doping layer 145 may be selectively formed only within the contact hole 140. That is, when the contact hole 140 is formed, the doping layer 145 may be selectively formed only within the contact hole 140 by doping, or may be formed in a portion of the second buffer layer where the contact hole 140 is to be formed.

[0085] The doping layer 145 may be formed by selectively doping the second buffer layer.

[0086] The doping layer 145 may be formed to overlap a portion of the display area AA and the non-display area. However, the present disclosure is not limited thereto.

[0087] For grounding, a contact hole 140 exposing the doping layer 145 of the second buffer layer through the polyimide substrate is formed in the edge region of the display panel, and the connection line 126 may be electrically connected to the doping layer 145 of the second buffer layer through the contact hole 140 .

[0088] The contact hole 140 may be at least one contact hole. Figure 3 It is illustrated that a total of six contact holes 140 are provided at four corners of the display panel and between the corners, but the number of the contact holes 140 in the present disclosure is not limited thereto.

[0089] In addition, the high potential power line 156 may be electrically connected to the high potential power pad. In this case, the high potential power line 156 may be a second power line. The high potential power line 156 may extend along the second direction of the substrate to be parallel to the plurality of data lines connected to the data pad. The high potential power line 156 may be electrically connected to the first electrode of the light emitting element through the transistor. Therefore, the high potential power line 156 may provide a high potential voltage to the first electrode. Figure 3 In the figure, for the convenience of description, only two high potential power lines 156 are shown, but the present disclosure is not limited thereto. The high potential power line 156 and the data line may be provided in plural so that they correspond to a plurality of sub-pixels PX, respectively.

[0090] refer to Figure 4 , the flexible display device according to the first exemplary embodiment of the present disclosure may include a substrate 110 , a transistor 120 , a light emitting element 130 , an encapsulation portion 115 h , and a support substrate 101 .

[0091] The substrate 110 is a substrate for supporting and protecting various components of the flexible display device. The substrate 110 may be formed of a plastic material having flexibility. When the substrate 110 is formed of a plastic material, for example, the substrate 110 may be formed of polyimide, but is not limited thereto.

[0092] The first buffer layer 111a may be disposed on the substrate 110. The first buffer layer 111a may improve adhesion between a layer formed on the first buffer layer 111a and the substrate 110, and block an alkali component or the like leaked from the substrate 110.

[0093] The first buffer layer 111a may be formed of a single layer of silicon nitride (SiNx) or silicon oxide (SiOx) or a multilayer of silicon nitride (SiNx) and silicon oxide (SiOx). The first buffer layer 111a may be omitted. For example, the first buffer layer 111a may be omitted based on the type and material of the substrate 110, the structure and type of the transistor 120, etc.

[0094] The light shielding pattern LS may be disposed on the first buffer layer 111a. The light shielding pattern LS may serve to block light incident from a lower portion to the active layer 124 of the transistor 120. The light shielding pattern LS may be omitted.

[0095] The first insulating layer 115 a may be disposed on the light-shielding pattern LS.

[0096] The first insulating layer 115a may be formed of a single layer of silicon nitride (SiNx) or silicon oxide (SiOx) or a multi-layer of silicon nitride (SiNx) and silicon oxide (SiOx).

[0097] The transistor 120 may be disposed on the first insulating layer 115 a .

[0098] The transistor 120 may include an active layer 124 , a gate 121 , a drain 123 , and a source 122 . Figure 4 The illustrated transistor 120 is a driving transistor, and is a thin film transistor having a top gate structure in which a gate 121 is disposed above an active layer 124. However, the present disclosure is not limited thereto, and the transistor 120 may be implemented as a thin film transistor having a bottom gate structure.

[0099] The active layer 124 may be formed of an oxide semiconductor, amorphous silicon, or polycrystalline silicon, but is not limited thereto. Polycrystalline silicon has superior mobility, low energy consumption, and excellent reliability than amorphous silicon, and thus may be applied to a driving transistor within a pixel.

[0100] Oxide semiconductors have excellent mobility and uniformity characteristics. The oxide semiconductor may be formed of: a quaternary metal oxide such as an indium tin gallium zinc oxide (InSnGaZnO) based material; a ternary metal oxide such as an indium gallium zinc oxide (InGaZnO) based material, an indium tin zinc oxide (InSnZnO) based material, a tin gallium zinc oxide (SnGaZnO) based material, an aluminum gallium zinc oxide (AlGaZnO) based material, an indium aluminum zinc oxide (InAlZnO) based material, and a tin aluminum zinc oxide (SnAlZnO) based material; or a binary metal oxide such as an indium zinc oxide (InZnO) based material, a tin zinc oxide (SnZnO) based material, an aluminum zinc oxide (AlZnO) based material, a zinc magnesium oxide (ZnMgO) based material, a tin magnesium oxide (SnMgO) based material, an indium magnesium oxide (InMgO) based material, and an indium gallium oxide (InGaO) based material; an indium oxide (InO) based material; a tin oxide (SnO) based material, and a zinc oxide (ZnO) based material. The composition ratio of each element included in the oxide semiconductor is not limited.

[0101] The active layer 124 may include a source region having p-type or n-type impurities, a drain region, and a channel region between the source region and the drain region. The active layer 124 may further include a low-concentration doping region between the source region and the drain region adjacent to the channel region.

[0102] In this case, the source region and the drain region are doped with high concentration impurities and may be connected to the source 122 and the drain 123 of the transistor 120 , respectively.

[0103] As the impurity ions, p-type impurities or n-type impurities can be used. The p-type impurity can be one of boron (B), aluminum (Al), gallium (Ga) and indium (In), and the n-type impurity can be one of phosphorus (P), arsenic (As) and antimony (Sb).

[0104] According to an NMOS or PMOS transistor structure, the channel region of the active layer 124 may be doped with n-type impurities or p-type impurities, and the transistor included in the flexible display device according to the first exemplary embodiment of the present disclosure may be an NMOS or PMOS transistor.

[0105] The second insulating layer 115b is a gate insulating layer composed of a single layer or a multilayer of silicon oxide (SiOx) or silicon nitride (SiNx), and may be disposed on the active layer 124 so that current flowing through the active layer 124 does not flow to the gate 121. In addition, silicon oxide has lower ductility than metal but better ductility than silicon nitride, and thus may be formed as a single layer or a multilayer depending on its characteristics.

[0106] The gate 121 serves as a switch for turning on or off the transistor 120, and may be composed of a single layer or multiple layers of a conductive metal, such as copper (Cu), aluminum (Al), molybdenum (Mo), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), and neodymium (Nd), or alloys thereof. However, embodiments of the present disclosure are not limited thereto.

[0107] The source electrode 122 or the drain electrode 123 is connected to a high potential power supply line, and can enable an electrical signal transmitted from the outside to be transmitted from the transistor 120 to the light emitting element 130. The source electrode 122 and the drain electrode 123 may be composed of a single layer or multiple layers of a conductive metal, such as copper (Cu), aluminum (Al), molybdenum (Mo), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), and neodymium (Nd), or alloys thereof, but are not limited thereto.

[0108] In order to insulate the gate 121 from the source 122 and the drain 123 , a third insulating layer 115 c composed of a single layer or multiple layers of silicon oxide (SiOx) or silicon nitride (SiNx) may be disposed between the gate 121 and the source 122 and the drain 123 .

[0109] At this time, contact holes for electrically connecting the drain electrode 123 and the source electrode 122 to the drain region and the source region of the active layer 124, respectively, may be formed in the second insulating layer 115b and the third insulating layer 115c.

[0110] A passivation layer formed of an inorganic insulating layer, for example, silicon oxide (SiOx) or silicon nitride (SiNx) may be further disposed on the transistor 120 .

[0111] The passivation layer may prevent unnecessary electrical connection between components disposed above and below the passivation layer and prevent external contamination or damage. Depending on the configuration and characteristics of the transistor 120 and the light emitting element 130, the passivation layer may be omitted.

[0112] The structure of the transistor 120 can be divided into an inverted staggered structure and a coplanar structure according to the positions of the elements constituting the transistor 120. For example, a transistor having an inverted staggered structure refers to a transistor having the following structure: the gate and the source and drain are located at opposite positions based on the active layer. Figure 4 In the embodiment, the transistor 120 having a coplanar structure refers to a transistor having the following structure: the gate 121 and the source 122 and the drain 123 are located on the same side based on the active layer 124 .

[0113] For the convenience of description, only a driving transistor is shown among various transistors that may be included in the flexible display device 100. In addition, a switching transistor, a capacitor, etc. may also be included in the flexible display device.

[0114] In this case, when a signal is applied from the gate line to the switching transistor, the switching transistor transmits the signal from the data line to the gate of the driving transistor. Through the signal transmitted from the switching transistor, the driving transistor can transmit the current transmitted through the power line to the first electrode 131, and can control the light emission by the current transmitted to the first electrode 131.

[0115] The planarization layers 115 d and 115 e may be disposed on the transistor 120 to protect the transistor 120 , thereby alleviating a step caused by the transistor 120 and reducing parasitic capacitance generated between the transistor 120 , the gate line, the data line, and the light emitting element 130 .

[0116] The planarization layers 115d and 115e may be formed of one or more materials selected from acrylic resin, epoxy resin, polyamide resin, polyimide resin, unsaturated polyester resin, phenol resin, polyphenylene ether resin, polyphenylene sulfide resin, and benzocyclobutene, but are not limited thereto.

[0117] The flexible display device according to the first exemplary embodiment of the present disclosure may include a first planarization layer 115d and a second planarization layer 115e sequentially stacked. That is, the first planarization layer 115d may be disposed on the transistor 120, and the second planarization layer 115e may be disposed on the first planarization layer 115d.

[0118] A buffer layer may be disposed on the first planarization layer 115d. The buffer layer may be composed of a multilayer silicon oxide (SiOx) to protect components disposed on the first planarization layer 115d, and may be omitted according to the configuration and characteristics of the transistor 120 and the light emitting element 130.

[0119] The intermediate electrode 125 may be connected to the transistor 120 through a contact hole formed in the first planarization layer 115d. The intermediate electrode 125 is stacked to be connected to the transistor 120, and the data line may also be formed in a multi-layer structure. However, the present disclosure is not limited thereto.

[0120] The data line may be formed to have a structure in which a lower layer formed of the same material as the source electrode 122 and the drain electrode 123 and an upper layer formed of the same material as the intermediate electrode 125 are connected to each other. That is, the data line may be implemented in a structure in which two layers are connected to each other in parallel, in which case the line resistance of the data line may be reduced.

[0121] Meanwhile, a passivation layer formed of an inorganic insulating layer such as silicon oxide (SiOx) or silicon nitride (SiNx) may be further disposed on the first planarization layer 115d and the intermediate electrode 125. The passivation layer may be used to prevent unnecessary electrical connection between components and to prevent external contamination or damage, and the passivation layer may be omitted according to the configuration and characteristics of the transistor 120 and the light emitting element 130.

[0122] The light emitting element 130 may be disposed on the second planarization layer 115 e .

[0123] The light emitting element 130 may include a first electrode 131 , a light emitting unit 132 , and a second electrode 133 .

[0124] The first electrode 131 as an anode may be disposed on the second planarization layer 115 e .

[0125] The first electrode 131 is used to supply holes to the light emitting unit 132 , and is connected to the intermediate electrode 125 through a contact hole in the second planarization layer 115 e , thereby being electrically connected to the transistor 120 .

[0126] The first electrode 131 may be formed of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), etc., but is not limited thereto.

[0127] When the flexible display device is a top emission type display device that emits light toward the upper portion where the second electrode 133 is disposed, a reflective layer may be further included so that the emitted light is reflected from the first electrode 131 and smoothly emitted in a direction toward the upper portion where the second electrode 133 is disposed.

[0128] That is, the first electrode 131 may be a two-layer structure in which a transparent conductive layer and a reflective layer formed of a transparent conductive material are sequentially stacked, or may be a three-layer structure in which a transparent conductive layer, a reflective layer, and a transparent conductive layer are sequentially stacked. The reflective layer may be formed of silver (Ag) or an alloy including silver.

[0129] The levee 115f disposed on the first electrode 131 and the second planarization layer 115e can define sub-pixels by dividing the area where light is actually emitted. After forming a photoresist on the first electrode 131, the levee 115f can be 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. The types of photoresists can be divided into positive photoresists and negative photoresists. A positive photoresist is a photoresist whose solubility in a developer increases due to exposure. When the positive photoresist is developed, a pattern with the exposed portion removed is obtained. A negative photoresist is a photoresist whose solubility in a developer is significantly reduced due to exposure. When the negative photoresist is developed, a pattern with the unexposed portion removed is obtained.

[0130] A fine metal mask (FMM) as a deposition mask may be used to form the light emitting unit 132 of the light emitting element 130 .

[0131] In addition, in order to prevent damage that may occur due to contact with a deposition mask set on the embankment 115f and maintain a constant distance between the embankment 115f and the deposition mask, a spacer 115g formed of one of polyimide (a transparent organic material), photo acrylic and benzocyclobutene (BCB) can be set on the embankment 115f.

[0132] The light emitting unit 132 may be disposed between the first electrode 131 and the second electrode 133 .

[0133] The light emitting unit 132 is used to emit light and may include at least one of a hole injection layer (HIL), a hole transport layer (HTL), a light emitting layer, an electron transport layer (ETL), and an electron injection layer (EIL), and some components may be omitted depending on the structure or characteristics of the flexible display device. Here, an electroluminescent layer and an inorganic light emitting layer may be used as the light emitting layer.

[0134] The hole injection layer is disposed on the first electrode 131 to facilitate injection of holes.

[0135] The hole transport layer is disposed on the hole injection layer to smoothly transport holes to the light emitting layer.

[0136] The light emitting layer is disposed on the hole transport layer and may include a material capable of emitting light of a specific color so as to emit light of the specific color. In addition, the light emitting material may be formed using a phosphorescent material or a fluorescent material.

[0137] An electron injection layer may be further disposed on the electron transport layer. The electron injection layer is an organic layer that facilitates electron injection from the second electrode 133, and may be omitted according to the structure and characteristics of the flexible display device.

[0138] At the same time, an electron blocking layer or a hole blocking layer that blocks the flow of holes or electrons is further arranged at a position adjacent to the light-emitting layer, thereby preventing the phenomenon that electrons move from the light-emitting layer and reach the adjacent hole transport layer when electrons are injected into the light-emitting layer, or preventing the phenomenon that holes move from the light-emitting layer and reach the adjacent electron transport layer when holes are injected into the light-emitting layer, thereby improving the luminescence efficiency.

[0139] The second electrode 133 as a cathode is disposed on the light emitting unit 132 to provide electrons to the light emitting unit 132. Since the second electrode 133 needs to provide electrons, it can be formed of a metal material as a conductive material with a low work function, such as magnesium (Mg) and silver magnesium (Ag:Mg), but is not limited thereto.

[0140] When the flexible display device is a top emission type display device, the second electrode 133 may be a transparent conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), zinc oxide (ZnO), and tin oxide (TO).

[0141] The encapsulation portion 115h may be disposed on the light emitting element 130 to prevent the transistor 120 and the light emitting element 130, which are components of the flexible display device, from being oxidized or damaged due to moisture, oxygen, or impurities introduced from the outside.

[0142] The encapsulation portion 115h may be formed by stacking a plurality of encapsulation layers, a foreign matter compensation layer, and a plurality of barrier films.

[0143] The encapsulation layer may be provided on the entire surface of the upper portion of the transistor 120 and the light emitting element 130, and may be formed of one of silicon nitride (SiNx) or aluminum oxide (AlyOz) as an inorganic material. However, the embodiment is not limited thereto. The encapsulation layer may be further provided on the foreign matter compensation layer provided on the encapsulation layer.

[0144] The foreign matter compensation layer is disposed on the encapsulation layer, and an organic material such as silicon oxycarbide (SiOCz), acrylic acid (propylene) or epoxy resin may be used for the foreign matter compensation layer. However, the embodiment is not limited thereto. When defects are generated due to cracks generated by foreign matter or particles that may be generated during processing, compensation can be performed by covering the cracks and foreign matter with the foreign matter compensation layer.

[0145] The barrier film may be disposed on the encapsulation layer and the foreign matter compensation layer, whereby the flexible display device may delay the penetration of oxygen and moisture from the outside. The barrier film is constructed in the form of a light-transmitting and double-sided adhesive film, and may be composed of any one of olefin-based, acrylic-based, and silicon-based insulating materials. Alternatively, a barrier film composed of any one of COP (cycloolefin polymer), COC (cycloolefin copolymer), and PC (polycarbonate) may be further stacked, but is not limited thereto.

[0146] Meanwhile, a supporting member may be further disposed under the display panel configured as described above, that is, under the substrate 110 .

[0147] When the substrate 110 of the display panel is formed of a plastic material such as polyimide, the manufacturing process of the flexible display device is performed with the support substrate 101 formed of glass disposed below the display panel. After the manufacturing process is completed, a certain thickness of the support substrate 101 may be etched so that it may be rollable or bendable, and thus, the support substrate 101 may be used as a support member. However, the present disclosure is not limited thereto, and the support substrate may be separated and detached. Since a structure for supporting the display panel is required even after the support substrate is detached, a protective film and an auxiliary substrate formed of a plastic material such as polyimide may be additionally attached to the display panel as a support member.

[0148] The second buffer layer 111 b may be disposed between the substrate 110 and the support substrate 101 .

[0149] The second buffer layer 111 b may be formed of a single layer of silicon nitride (SiNx) or silicon oxide (SiOx) or a multilayer of silicon nitride (SiNx) and silicon oxide (SiOx), but is not limited thereto.

[0150] The support substrate 101 and the second buffer layer 111 b may prevent foreign matter from being attached to the lower portion of the substrate 110 , and may serve to buffer an impact from the outside.

[0151] Figure 5 It is shown Figure 3 A cross-sectional view showing the detailed structure of the non-display area.

[0152] Figure 5 Some of the components in Figure 4 The components described in are substantially the same and similar, and thus their description is omitted.

[0153] refer to Figure 5 , the substrate 110 may be configured to support and protect various components of the flexible display device.

[0154] The substrate 110 may be formed of a plastic material having flexibility. When the substrate 110 is formed of a plastic material, for example, the substrate 110 may be formed of polyimide, but is not limited thereto.

[0155] A second buffer layer may be disposed under the substrate 110 .

[0156] A support substrate 101 formed of glass may be disposed under the second buffer layer.

[0157] In order to improve the brightness defect in the edge area of ​​the display panel due to the charging of the polyimide substrate, a doping layer (or a conductive layer) 145 may be formed in the second buffer layer under the substrate 110 .

[0158] The doping layer 145 may be formed by selectively doping the second buffer layer.

[0159] As the impurity ions for doping, p-type impurities or n-type impurities can be used. The p-type impurity can be one of boron (B), aluminum (Al), gallium (Ga) and indium (In), and the n-type impurity can be one of phosphorus (P), arsenic (As) and antimony (Sb). However, the present disclosure is not limited thereto.

[0160] Instead of doping with impurity ions, a metal layer may be additionally formed on or inside the second buffer layer. The inner metal layer may be composed of a conductive metal such as copper (Cu), aluminum (Al), chromium (Cr), gold (Au), molybdenum (Mo), titanium (Ti), and nickel (Ni), or may be composed of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), etc.

[0161] The doping layer 145 may be formed in a quadrilateral frame shape, overlapping a portion of the display area and the non-display area. However, the present disclosure is not limited thereto. As described above, the doping layer 145 may be selectively formed only within the contact hole 140 .

[0162] Meanwhile, a first buffer layer 111 a may be disposed on the substrate 110 .

[0163] A contact hole 140 exposing a portion of the doping layer 145 may be formed in the first buffer layer 111a and the substrate 110 in the non-display region. The contact hole 140 may penetrate the first buffer layer 111a and the substrate 110 to expose a portion of the doping layer 145.

[0164] The connection line 126 may be disposed on the first buffer layer 111 a in the non-display area.

[0165] The connection line 126 may be connected to the low potential power supply pad in, for example, a quadrangular frame shape. However, the present disclosure is not limited thereto.

[0166] The connection line 126 may be formed of a light shielding pattern of the display region, an electrode of a transistor, or a first electrode or a second electrode of a light emitting element.

[0167] Figure 5 An example in which the connection line 126 is formed of a conductive material constituting the light shielding pattern when the light shielding pattern is formed in the display area is illustrated, but the present disclosure is not limited thereto.

[0168] The connection line 126 may be electrically connected to the doping layer 145 of the second buffer layer through the contact hole 140 .

[0169] The first insulating layer 115 a may be disposed on the connection line 126 .

[0170] The components disposed on the first insulating layer 115a are Figure 4 The components described in are substantially the same and similar, so their description will be omitted.

[0171] Meanwhile, in addition to the light shielding pattern, the connection line of the present disclosure may be composed of an electrode of a transistor, or a first electrode or a second electrode of a light emitting element. Figure 6 A second exemplary embodiment is described in detail in which the connection line is constituted by the source and drain of a transistor.

[0172] Figure 6 is a cross-sectional view illustrating a portion of a non-display area in a flexible display device according to a second exemplary embodiment of the present disclosure.

[0173] In addition to the components of the connection line 226 and the contact hole 240, Figure 6 The second exemplary embodiment of the present disclosure may be configured to have substantially the same components as the first exemplary embodiment of the present disclosure. Therefore, description of the same components will be omitted.

[0174] Figure 6 is a cross-sectional view showing a detailed structure of a non-display area.

[0175] refer to Figure 6 , the substrate 110 may be provided to support and protect various components of the flexible display device.

[0176] The substrate 110 may be formed of a plastic material having flexibility. When the substrate 110 is formed of a plastic material, for example, the substrate 110 may be formed of polyimide, but is not limited thereto.

[0177] A second buffer layer may be disposed under the substrate 110 .

[0178] A support substrate 101 formed of glass may be disposed under the second buffer layer.

[0179] In order to improve the brightness defect in the edge area of ​​the display panel due to the charging of the polyimide substrate, a doping layer (or a conductive layer) 145 may be formed in the second buffer layer under the substrate 110 .

[0180] The doping layer 145 may be formed by selectively doping the second buffer layer.

[0181] As the impurity ions for doping, p-type impurities or n-type impurities can be used. The p-type impurity can be one of boron (B), aluminum (Al), gallium (Ga) and indium (In), and the n-type impurity can be one of phosphorus (P), arsenic (As) and antimony (Sb). However, the present disclosure is not limited thereto.

[0182] Instead of doping with impurity ions, a metal layer may be additionally formed on or inside the second buffer layer. The inner metal layer may be composed of a conductive metal such as copper (Cu), aluminum (Al), chromium (Cr), gold (Au), molybdenum (Mo), titanium (Ti), and nickel (Ni), or may be composed of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), etc.

[0183] The doping layer 145 may be formed in a quadrilateral frame shape, overlapping a portion of the display area and the non-display area. However, the present disclosure is not limited thereto. As described above, the doping layer 145 may be selectively formed only within the contact hole 240, or may be formed in a portion of the second buffer layer where the contact hole 240 is to be formed.

[0184] Meanwhile, a first buffer layer 111 a may be disposed on the substrate 110 .

[0185] The first insulating layer 115 a may be disposed on the first buffer layer 111 a .

[0186] The second insulating layer 115 b may be disposed on the first insulating layer 115 a .

[0187] The third insulating layer 115c may be disposed on the second insulating layer 115b.

[0188] In the second exemplary embodiment of the present disclosure, a contact hole 240 exposing a portion of the doping layer 145 may be formed in the first buffer layer 111a, the first insulating layer 115a, the second insulating layer 115b, the third insulating layer 115c, and the substrate 110 in the non-display area. In this case, the contact hole 240 may penetrate the first buffer layer 111a, the first insulating layer 115a, the second insulating layer 115b, the third insulating layer 115c, and the substrate 110 to expose a portion of the doping layer 145.

[0189] In addition, the connection line 226 may be disposed on the third insulating layer 115 c in the non-display area.

[0190] The connection line 226 may be connected to the low potential power supply pad in, for example, a quadrangular frame shape. However, the present disclosure is not limited thereto.

[0191] The connection line 226 may be formed of a conductive material constituting a source and a drain of a transistor in the display region, but is not limited thereto.

[0192] The connection line 226 may be electrically connected to the doping layer 145 of the second buffer layer through the contact hole 240 .

[0193] The first planarization layer 115 d may be disposed on the connection line 226 .

[0194] The components disposed on the first planarization layer 115 d are substantially the same as and similar to those of the first exemplary embodiment of the present disclosure described above, and thus, a description thereof will be omitted.

[0195] Meanwhile, in addition to the etching glass, the support member disposed under the polyimide substrate of the present disclosure may also be composed of another polyimide substrate, which will be referred to in Figure 7 and Figure 8 Describe in detail.

[0196] Figure 7 is a cross-sectional view illustrating a portion of a display area in a flexible display device according to a third exemplary embodiment of the present disclosure.

[0197] Figure 8 is a cross-sectional view illustrating a portion of a non-display area in a flexible display device according to a third exemplary embodiment of the present disclosure.

[0198] refer to Figure 7 , the flexible display device according to the third exemplary embodiment of the present disclosure may include a substrate 310 a , a transistor 120 , a light emitting element 130 , an encapsulation part 115 h , and an auxiliary substrate 310 b .

[0199] The substrate 310a may be formed of a plastic material having flexibility. When the substrate 310a is formed of a plastic material, for example, the substrate 310a may be formed of polyimide, but is not limited thereto.

[0200] The first buffer layer 311a may be disposed on the substrate 310a. The first buffer layer 311a may improve adhesion between a layer formed on the first buffer layer 311a and the substrate 310a, and may block an alkali component and the like leaked from the substrate 310a.

[0201] The first buffer layer 311a may be formed of a single layer of silicon nitride (SiNx) or silicon oxide (SiOx) or a multilayer of silicon nitride (SiNx) and silicon oxide (SiOx). The first buffer layer 311a may be omitted. For example, the first buffer layer 311a may be omitted based on the type and material of the substrate 310a, the structure and type of the transistor 120, etc.

[0202] The light shielding pattern LS may be disposed on the first buffer layer 311 a .

[0203] The first insulating layer 115 a may be disposed on the light-shielding pattern LS.

[0204] The transistor 120 may be disposed on the first insulating layer 115 a .

[0205] The transistor 120 may include an active layer 124 , a gate 121 , a drain 123 , and a source 122 .

[0206] Since the transistor 120 is substantially the same as the transistor of the first exemplary embodiment of the present disclosure described above, a description thereof will be omitted.

[0207] The second insulating layer 115 b may be disposed on the active layer 124 .

[0208] In addition, a third insulating layer 115 c may be disposed between the gate 121 and the source 122 and the drain 123 .

[0209] A first planarization layer 115 d may be disposed on the transistor 120 , and a second planarization layer 115 e may be disposed on the first planarization layer 115 d .

[0210] The intermediate electrode 125 may be electrically connected to the transistor 120 through a contact hole formed in the first planarization layer 115 d .

[0211] The light emitting element 130 may be disposed on the second planarization layer 115 e .

[0212] The light emitting element 130 may include a first electrode 131 , a light emitting unit 132 , and a second electrode 133 , and is substantially the same as the light emitting element of the first exemplary embodiment of the present disclosure described above. Therefore, the description of the light emitting element 130 will be omitted.

[0213] The bank 115 f may be disposed on the first electrode 131 and the second planarization layer 115 e .

[0214] In addition, the spacer 115g may be disposed on the bank 115f.

[0215] The encapsulation portion 115 h may be disposed on the light emitting element 130 .

[0216] The encapsulation portion 115h may be formed by stacking a plurality of encapsulation layers, a foreign matter compensation layer, and a plurality of barrier films.

[0217] Meanwhile, a supporting member may be further disposed under the display panel configured as described above, that is, under the substrate 310 a .

[0218] The support member according to the third exemplary embodiment of the present disclosure may include a protective film 312 and an auxiliary substrate 310 b formed of a plastic material such as polyimide.

[0219] The second buffer layer 311 b may be disposed between the substrate 310 a and the supplementary substrate 310 b .

[0220] Figure 8 Some of the components in Figure 7 The components described in are substantially the same and similar, so their description will be omitted.

[0221] refer to Figure 8 , a second buffer layer may be disposed under the substrate 310 a in the non-display area.

[0222] An auxiliary substrate 310 b and a protective film 312 formed of a plastic material such as polyimide may be sequentially disposed under the second buffer layer.

[0223] In order to improve the brightness defect in the edge region of the display panel due to the charging of the polyimide substrate 310 a , a doping layer (or a conductive layer) 345 may be formed in the second buffer layer under the substrate 310 a .

[0224] The doping layer 345 may be formed by selectively doping the second buffer layer.

[0225] As the impurity ions for doping, p-type impurities or n-type impurities can be used. The p-type impurity can be one of boron (B), aluminum (Al), gallium (Ga) and indium (In), and the n-type impurity can be one of phosphorus (P), arsenic (As) and antimony (Sb). However, the present disclosure is not limited thereto.

[0226] Instead of doping with impurity ions, a metal layer may be additionally formed on or inside the second buffer layer 311b. The inner metal layer may be composed of a conductive metal such as copper (Cu), aluminum (Al), chromium (Cr), gold (Au), molybdenum (Mo), titanium (Ti), and nickel (Ni), or may be composed of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), etc.

[0227] The doping layer 345 may be formed in a quadrilateral frame shape, overlapping a portion of the display area and the non-display area. However, the present disclosure is not limited thereto. As described above, the doping layer 345 may be selectively formed only within the contact hole 340, or may be formed in a portion of the second buffer layer where the contact hole 340 is to be formed.

[0228] Meanwhile, a first buffer layer 311 a may be disposed on the substrate 310 a .

[0229] A contact hole 340 exposing a portion of the doping layer 345 may be formed in the first buffer layer 311 a and the substrate 310 a in the non-display region. The contact hole 340 may penetrate the first buffer layer 311 a and the substrate 310 a to expose a portion of the doping layer 345 .

[0230] The connection line 326 may be disposed on the first buffer layer 311 a in the non-display area.

[0231] The connection line 326 may be connected to the low potential power supply pad in, for example, a quadrangular frame shape. However, the present disclosure is not limited thereto.

[0232] The connection line 326 may be formed by a light shielding pattern of the display region, an electrode of a transistor, or a first electrode or a second electrode of a light emitting element.

[0233] Figure 8 An example in which the connection line 326 is formed of a conductive material constituting the light shielding pattern when the light shielding pattern is formed in the display area is illustrated, but the present disclosure is not limited thereto.

[0234] The connection line 326 may be electrically connected to the doping layer 345 of the second buffer layer through the contact hole 340 .

[0235] The first insulating layer 115 a may be disposed on the connection line 326 .

[0236] The components disposed on the first insulating layer 115a are Figure 7 The components described in are substantially the same and similar, so their description will be omitted.

[0237] Meanwhile, in the present disclosure, a metal layer is formed in the second buffer layer instead of a doped layer, so the metal layer is electrically connected to the connection line through the contact hole, which will be referred to as Fig. 9 Detailed description.

[0238] Fig. 9 is a cross-sectional view illustrating a portion of a non-display area in a flexible display device according to a fourth exemplary embodiment of the present disclosure.

[0239] Fig. 9 Some parts of Figure 8 The components shown are substantially the same and similar, and thus description thereof is omitted.

[0240] refer to Fig. 9 , a second buffer layer 411 b may be disposed under the substrate 310 a in the non-display area.

[0241] An auxiliary substrate 310 b and a protective film 312 formed of a plastic material such as polyimide may be sequentially disposed under the second buffer layer 411 b .

[0242] In order to improve the brightness defect in the edge region of the display panel due to the charging of the polyimide substrate 310 a , a metal layer 427 may be formed in the second buffer layer 411 b .

[0243] That is, the second buffer layer 411b of the fourth exemplary embodiment of the present disclosure may include a second upper buffer layer 411b' under the substrate 310a and a second lower buffer layer 411b' under the second upper buffer layer 411b'. However, the present disclosure is not limited thereto, and the second buffer layer 411b may be formed of a single layer or a multilayer of two or more layers.

[0244] In addition, the metal layer 427 may be formed at an interface between the second upper buffer layer 411b′ and the second lower buffer layer 411b″. However, the present disclosure is not limited thereto. When the second buffer layer 411b is formed of a single layer, the metal layer 427 may be formed anywhere inside the second buffer layer 411b. The metal layer 427 may also be formed on the second buffer layer 411b.

[0245] The metal layer 427 may be composed of a conductive metal such as copper (Cu), aluminum (Al), chromium (Cr), gold (Au), molybdenum (Mo), titanium (Ti) and nickel (Ni), or may be composed of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), etc.

[0246] The metal layer 427 may be selectively formed only within the contact hole 440, or may be formed in a portion of the second lower buffer layer 411 b″ where the contact hole 440 is to be formed. The metal layer 427 may be formed in a quadrilateral frame shape overlapping a portion of the display area and the non-display area.

[0247] Meanwhile, a first buffer layer 311 a may be disposed on the substrate 310 a .

[0248] Contact holes 440 exposing a portion of metal layer 427 may be formed in first buffer layer 311a, substrate 310a, and second upper buffer layer 411b' in the non-display area. Contact holes 440 may penetrate first buffer layer 311a, substrate 310a, and second upper buffer layer 411b' to expose a portion of metal layer 427.

[0249] The connection line 426 may be disposed on the first buffer layer 311 a in the non-display area.

[0250] The connection line 426 may be connected to the low potential power supply pad in, for example, a quadrangular frame shape. However, the present disclosure is not limited thereto.

[0251] The connection line 426 may be formed of a light shielding pattern of the display region, an electrode of a transistor, or a first electrode or a second electrode of a light emitting element.

[0252] In this case, the connection line 426 may be electrically connected to the metal layer 427 inside the second buffer layer 411 b through the contact hole 440 .

[0253] Meanwhile, the connection line of the present disclosure may be formed by the second electrode of the light emitting element, which will be referred to as Fig.10 and Fig.11 Describe in detail.

[0254] Fig.10 is a plan view of a flexible display device according to a fifth exemplary embodiment of the present disclosure.

[0255] Fig.11 is along Fig.10 A cross-sectional view taken along line III-III'.

[0256] Fig.11 Show reference Fig.10 Describes the detailed structure of the non-display area.

[0257] refer to Fig.10 , the flexible display device 500 according to the fifth exemplary embodiment of the present disclosure includes a display area AA and a non-display area.

[0258] For convenience, the non-display area may be defined as an area other than the display area AA, and description of reference numerals thereof will be omitted.

[0259] The display area AA may be disposed at the center of the display panel, and may be an area where an image is displayed in the flexible display device 500 .

[0260] The display area AA may include a plurality of sub-pixels PX.

[0261] The non-display area corresponds to an edge area of ​​the display panel and may be an area where no image is displayed. The non-display area may be disposed to surround the display area AA.

[0262] The non-display area includes a pad area. For example, the pad area may be provided at the lower end of the display panel. The pad area may include a plurality of pads 155 and signal lines connected to the plurality of pads 155. A driver IC, a drive circuit or a flexible film may be connected to the pad area through the plurality of pads 155. The driver IC, the drive circuit or the flexible film may transmit various drive signals, low potential voltages and high potential voltages to the plurality of pads 155.

[0263] The plurality of pads 155 receive various driving signals for driving the flexible display device 500 and provide them to components of the flexible display device 500 , such as a plurality of sub-pixels PX, so that the flexible display device 500 may be driven.

[0264] The plurality of pads 155 include: a data pad for providing a data signal to each of the plurality of sub-pixels PX; a high potential power pad for providing a high potential voltage to the first electrode of the light emitting element; and a low potential power pad for providing a low potential voltage to the second electrode of the light emitting element.

[0265] For example, a low potential power pad can be provided at both ends of a plurality of pads 155. A low potential power line can be electrically connected to the low potential power pad. In this case, the low potential power line can be a first power line. The second electrode of the light emitting element can be electrically connected to the low potential power line. Therefore, the low potential power line can supply a low potential voltage to the second electrode.

[0266] In addition, the second electrode 533 may be electrically connected to a low potential power supply pad.

[0267] The second electrode 533 may extend to the non-display area and may be electrically connected to the doping layer (or conductive layer) 145 of the lower buffer layer. That is, the second electrode 533 extending through the plurality of contact holes 540 is electrically connected to the doping layer (or conductive layer) 145 of the lower buffer layer and may also be connected (or grounded) to a low potential power line.

[0268] The second electrode 533 may be connected to the pad 155 , ie, a low potential power supply pad, for example, in a rectangular shape.

[0269] The second electrode 533 may be formed of a metal material having high conductivity. The second electrode 533 may be formed by extending a cathode of the light emitting element in the display area AA.

[0270] In this case, the second electrode 533 may be formed to overlap a portion of the non-display area as well as the display area AA.

[0271] A doping layer (or conductive layer) 145 having a quadrilateral frame shape may be formed in the second buffer layer below the polyimide substrate. As described above, the doping layer 145 may be selectively formed only within the contact hole 540, or may be formed in a portion of the second buffer layer where the contact hole 540 is to be formed.

[0272] The doping layer 145 may be formed by selectively doping the second buffer layer.

[0273] The doping layer 145 may be formed to overlap a portion of the display area AA and the non-display area. However, the present disclosure is not limited thereto.

[0274] The second electrode 533 may extend in a direction toward the non-display region so as to overlap a portion of the doping layer 145 .

[0275] For grounding, a contact hole 540 is formed in the edge region of the display panel, the contact hole 540 exposes the doping layer 145 of the second buffer layer through the polyimide substrate, and the second electrode 533 may be electrically connected to the doping layer 145 of the second buffer layer through the contact hole 540 .

[0276] The connection lines 126 , 226 , 326 , and 426 described above in the present disclosure and the second electrode 533 according to the fifth exemplary embodiment of the present disclosure may be referred to as a connection member.

[0277] The contact hole 540 may be at least one contact hole. Fig.10An example is shown in which a total of six contact holes 540 are provided at four corners of the display panel and between the corners, but the number of the contact holes 540 in the present disclosure is not limited thereto.

[0278] In addition, the high potential power line 156 can be electrically connected to the high potential power pad. In this case, the high potential power line 156 can be a second power line. The high potential power line 156 can extend in the second direction of the substrate to be parallel to the plurality of data lines connected to the data pad. The high potential power line 156 can be electrically connected to the first electrode of the light emitting element. That is, the high potential power line 156 can be electrically connected to the first electrode of the light emitting element through the transistor. Therefore, the high potential power line 156 can provide a high potential voltage to the first electrode. Fig.10 In the figure, for the convenience of description, only two high potential power lines 156 are shown, but the present disclosure is not limited thereto. The high potential power line 156 and the data line may be provided in plural so that they correspond to a plurality of sub-pixels PX, respectively.

[0279] refer to Fig.11 , a second buffer layer may be disposed under the substrate 110 in the non-display area.

[0280] The substrate 110 may be formed of a plastic material having flexibility. When the substrate 110 is formed of a plastic material, for example, the substrate 110 may be formed of polyimide, but is not limited thereto.

[0281] A support substrate 101 formed of glass may be disposed under the second buffer layer.

[0282] In order to improve the brightness defect in the edge region of the display panel due to the charging of the polyimide substrate 110 , a doping layer (or a conductive layer) 145 may be formed in the second buffer layer under the substrate 110 .

[0283] The doping layer 145 may be formed by selectively doping the second buffer layer.

[0284] As the impurity ions for doping, p-type impurities or n-type impurities can be used. The p-type impurity can be one of boron (B), aluminum (Al), gallium (Ga) and indium (In), and the n-type impurity can be one of phosphorus (P), arsenic (As) and antimony (Sb). However, the present disclosure is not limited thereto.

[0285] Instead of doping with impurity ions, a metal layer may be additionally formed on or inside the second buffer layer. The inner metal layer may be composed of a conductive metal such as copper (Cu), aluminum (Al), chromium (Cr), gold (Au), molybdenum (Mo), titanium (Ti), and nickel (Ni), or may be composed of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), etc.

[0286] The doping layer 145 may be formed in a quadrangular frame shape overlapping a portion of the display area and the non-display area. However, the present disclosure is not limited thereto.

[0287] Meanwhile, a first buffer layer 111 a may be disposed on the substrate 110 .

[0288] The first insulating layer 115 a may be disposed on the first buffer layer 111 a .

[0289] The second insulating layer 115 b may be disposed on the first insulating layer 115 a .

[0290] The third insulating layer 115c may be disposed on the second insulating layer 115b.

[0291] The first planarization layer 115 d and the second planarization layer 115 e may be disposed on the third insulating layer 115 c .

[0292] The bank 115f may be disposed on the second planarization layer 115e.

[0293] A contact hole 540 exposing a portion of the doping layer 145 may be formed in the first buffer layer 111a, the first insulating layer 115a, the second insulating layer 115b, the third insulating layer 115c, the first planarization layer 115d, the second planarization layer 115e, the bank 115f, and the substrate 110. The contact hole 540 may penetrate the first buffer layer 111a, the first insulating layer 115a, the second insulating layer 115b, the third insulating layer 115c, the first planarization layer 115d, the second planarization layer 115e, the bank 115f, and the substrate 110 to expose a portion of the doping layer 145.

[0294] A light emitting element including a first electrode, a light emitting unit, and a second electrode 533 may be disposed in the display region. Also, the second electrode 533 in the display region may extend onto the bank 115f in the non-display region.

[0295] The second electrode 533 may extend to the non-display region and be electrically connected to the doping layer (or conductive layer) 145 of the second buffer layer. That is, the second electrode 533 extending through the plurality of contact holes 540 may be electrically connected to the doping layer (or conductive layer) 145 of the second buffer layer, and may also be connected (or grounded) to a low potential power line.

[0296] The second electrode 533 may be connected to the pad 155 , ie, a low potential power supply pad, for example, in a rectangular shape.

[0297] The second electrode 533 may be formed of a metal material having high conductivity.

[0298] The second electrode 533 may be formed to overlap a portion of the non-display area as well as the display area.

[0299] The encapsulation portion 115 h may be disposed on the second electrode 533 .

[0300] Meanwhile, as described above, the doping layer of the present disclosure may be selectively formed only in the contact hole, which will be referred to as Fig.12 and Fig.13 Describe in detail.

[0301] Fig.12 is a plan view of a flexible display device according to a sixth exemplary embodiment of the present disclosure.

[0302] Fig.13 It is along Fig.12 A cross-sectional view taken along line IV-IV'.

[0303] Fig.13 Show reference Fig.12 Describes the detailed structure of the non-display area.

[0304] refer to Fig.12 , the flexible display device 600 according to the sixth exemplary embodiment of the present disclosure includes a display area AA and a non-display area.

[0305] For convenience, the non-display area may be defined as an area other than the display area AA, and description of reference numerals thereof will be omitted.

[0306] The display area AA may be disposed at the center of the display panel, and may be an area where an image is displayed in the flexible display device 600 .

[0307] The display area AA may include a plurality of sub-pixels PX.

[0308] The non-display area corresponds to an edge area of ​​the display panel and may be an area where no image is displayed. The non-display area may be disposed to surround the display area AA.

[0309] The non-display area includes a pad area. For example, the pad area may be provided at the lower end of the display panel. The pad area may include a plurality of pads 155 and signal lines connected to the plurality of pads 155. A driver IC, a drive circuit or a flexible film may be connected to the pad area through the plurality of pads 155. The driver IC, the drive circuit or the flexible film may transmit various drive signals, low potential voltages and high potential voltages to the plurality of pads 155.

[0310] The plurality of pads 155 receive various driving signals for driving the flexible display device 600 and provide them to components of the flexible display device 600 , such as a plurality of sub-pixels PX, so that the flexible display device 600 may be driven.

[0311] The plurality of pads 155 include: a data pad for providing a data signal to each of the plurality of sub-pixels PX; a high potential power pad for providing a high potential voltage to the first electrode of the light emitting element; and a low potential power pad for providing a low potential voltage to the second electrode of the light emitting element.

[0312] In addition, the connection line 126 may be electrically connected to a low potential power supply pad.

[0313] The connection line 126 may be electrically connected to the doping layer (or conductive layer) 645 of the lower buffer layer. That is, the connection line 126 is electrically connected to the doping layer 645 of the lower buffer layer through the plurality of contact holes 640 and may be connected (or grounded) to a low potential power line.

[0314] The connection line 126 may be connected to the pad 155 , ie, the low potential power supply pad, in a quadrangular frame shape.

[0315] The connection line 126 may be formed of a metal material having high conductivity. The connection line 126 may be formed of a light shielding pattern of the display area AA, an electrode of a transistor, or a first electrode or a second electrode of a light emitting element.

[0316] In the second buffer layer under the polyimide substrate, a doping layer 645 may be formed in a region corresponding to the contact hole 640 .

[0317] The doping layer 645 may be formed by selectively doping the second buffer layer.

[0318] For grounding, a contact hole 640 exposing the doping layer 645 of the second buffer layer through the polyimide substrate is formed in the edge region of the display panel, and the connection line 126 may be electrically connected to the doping layer 645 of the second buffer layer through the contact hole 640 .

[0319] The contact hole 640 may be at least one contact hole. Fig.12 An example is shown in which a total of six contact holes 640 are provided at four corners of the display panel and between the corners, but the number of the contact holes 640 in the present disclosure is not limited thereto.

[0320] In addition, the high potential power supply line 156 may be electrically connected to the high potential power supply pad. In this case, the high potential power supply line 156 may be a second power supply line.

[0321] refer to Fig.13 , the substrate 110 may be configured to support and protect various components of the flexible display device.

[0322] The substrate 110 may be formed of a plastic material having flexibility. When the substrate 110 is formed of a plastic material, for example, the substrate 110 may be formed of polyimide, but is not limited thereto.

[0323] The second buffer layer 611 b may be disposed under the substrate 110 .

[0324] A support substrate 101 formed of glass may be disposed under the second buffer layer 611 b .

[0325] In order to improve the brightness defect in the edge region of the display panel due to the charging of the polyimide substrate 110 , a doping layer (or a conductive layer) 645 may be formed in the second buffer layer 611 b under the substrate 110 .

[0326] The doping layer 645 may be formed by selectively doping the second buffer layer 611 b .

[0327] The doping layer 645 may be selectively formed only in the contact hole 640. That is, when the contact hole 640 is formed, the doping layer 645 may be selectively formed only in the contact hole 640 by doping. Alternatively, the doping layer 645 may be formed in a portion of the second buffer layer 611b where the contact hole 640 is to be formed.

[0328] As the impurity ions for doping, p-type impurities or n-type impurities can be used. The p-type impurity can be one of boron (B), aluminum (Al), gallium (Ga) and indium (In), and the n-type impurity can be one of phosphorus (P), arsenic (As) and antimony (Sb). However, the present disclosure is not limited thereto.

[0329] Instead of doping with impurity ions, a metal layer may be additionally formed on or inside the second buffer layer 611b. The inner metal layer may be composed of a conductive metal such as copper (Cu), aluminum (Al), chromium (Cr), gold (Au), molybdenum (Mo), titanium (Ti), and nickel (Ni), or may be composed of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), etc.

[0330] Meanwhile, a first buffer layer 111 a may be disposed on the substrate 110 .

[0331] A contact hole 640 exposing a portion or all of the doping layer 645 may be formed in the first buffer layer 111a and the substrate 110 in the non-display region. That is, the contact hole 640 may penetrate the first buffer layer 111a and the substrate 110 to expose a portion or all of the doping layer 645.

[0332] The connection line 126 may be disposed on the first buffer layer 111 a in the non-display area.

[0333] The connection line 126 may be connected to the low potential power supply pad in, for example, a quadrangular frame shape. However, the present disclosure is not limited thereto.

[0334] The connection line 126 may be formed by a light shielding pattern of the display region, an electrode of a transistor, or a first electrode or a second electrode of a light emitting element.

[0335] Fig.13 An example in which the connection line 126 is formed of a conductive material constituting the light shielding pattern when the light shielding pattern is formed in the display area is illustrated, but the present disclosure is not limited thereto.

[0336] The connection line 126 may be electrically connected to the doping layer 645 of the second buffer layer 611 b through the contact hole 640 .

[0337] The first insulating layer 115 a may be disposed on the connection line 126 .

[0338] The components disposed on the first insulating layer 115a are Figure 4 The components described are substantially the same and similar, so their description will be omitted.

[0339] The above-described flexible display devices according to the first to sixth exemplary embodiments of the present disclosure may be applied to a rollable display device, and hereinafter, the rollable display device will be described in detail.

[0340] Fig.14A and Fig. 14B is a perspective view of a flexible display device according to the present disclosure.

[0341] That is to say, Fig.14A and Fig. 14B A rollable display device is illustrated as a flexible display device by way of example, but the present disclosure is not limited thereto.

[0342] The rollable display device may also be referred to as a display device that can display an image even when the display device is rolled up. Compared with a general display device of the related art, the rollable display device may have high flexibility. Depending on whether the rollable display device is used, the shape of the rollable display device may be freely changed. Specifically, when the rollable display device is not used, the rollable display device may be rolled up into a reduced volume for storage. On the contrary, when the rollable display device is used, the rolled-up rollable display device may be unfolded for use.

[0343] refer to Fig.14A and Fig. 14B , the display device 100 according to the exemplary embodiment of the present disclosure includes a display part DP and a housing part HP.

[0344] The display portion DP is configured to display an image to a user. For example, a display element, a circuit for driving the display element, a line, and other components may be provided in the display portion DP.

[0345] The display device 100 according to the exemplary embodiment of the present disclosure is a rollable display device. Therefore, the display portion DP may be configured to be rolled and unfolded. For example, the display portion DP may include a flexible display panel and a back cover so that they can be rolled or unfolded.

[0346] The housing portion HP serves as a housing that can accommodate the display portion DP. The display portion DP can be rolled and then accommodated in the housing portion HP, and the display portion DP can be unfolded and then can be disposed outside the housing portion HP.

[0347] The housing portion HP includes an opening HPO through which the display portion DP can enter and exit the housing portion HP. The display portion DP can move in a vertical direction through the opening HPO of the housing portion HP.

[0348] Meanwhile, the display portion DP may transition from a fully unfolded state to a fully rolled state, and vice versa.

[0349] Fig.14A 1 shows a fully unfolded state of the display portion DP of the display device 100. The fully unfolded state refers to a state in which the display portion DP of the display device 100 is disposed outside the housing portion HP. That is, the fully unfolded state can be defined as a state in which the display portion DP is unfolded and disposed outside the housing portion HP to the greatest extent, so that the user can view images on the display device 100. And, in the fully unfolded state, the display portion DP cannot be further unfolded.

[0350] Fig. 14B The fully rolled-up state of the display portion DP of the display device 100 is shown. The fully rolled-up state refers to a state in which the display portion DP of the display device 100 is accommodated in the housing portion HP and cannot be further rolled up. That is, the fully rolled-up state can be defined as a state in which the display portion DP is rolled up and accommodated in the housing portion HP when the user is not viewing an image on the display device 100, because in terms of appearance, the display portion DP is preferably not provided outside the housing portion HP. In addition, in the fully rolled-up state in which the display portion DP is accommodated in the housing portion HP, the volume of the display device 100 is reduced and transportation is facilitated.

[0351] Meanwhile, a driving portion for rolling or unfolding the display portion DP to switch the display portion DP to a fully unfolded state or a fully rolled state may be provided.

[0352] In the rollable display device configured as above according to an exemplary embodiment of the present disclosure, a doping layer (or a conductive layer) is formed in the lower buffer layer in the edge area of ​​the display panel and is connected (grounded) to a low potential power line through a contact hole, so that the charge accumulated in the polyimide substrate can be removed, minimizing the uneven brightness of the display panel caused by the use of the polyimide substrate.

[0353] Exemplary embodiments of the present disclosure may also be described as follows:

[0354] According to one aspect of the present disclosure, a flexible display device is provided. The flexible display device includes: a substrate, divided into a display area and a non-display area; a first buffer layer, arranged above the substrate; a second buffer layer, arranged below the substrate; a support member, arranged below the second buffer layer; a transistor and a light-emitting element, arranged above the first buffer layer in the display area; a conductive layer, arranged in the second buffer layer in the non-display area; and a connecting member, arranged on the first buffer layer in the non-display area and electrically connected to the conductive layer through a contact hole.

[0355] The substrate may be made of polyimide (PI).

[0356] The support member may be made of etched glass.

[0357] The supporting member may include: an auxiliary substrate made of polyimide; and a protective film under the auxiliary substrate.

[0358] The transistor may include a gate, an active layer, a source, and a drain, and the connection member may be made of a conductive material constituting the gate or the source / drain, and located on the same layer as the gate or the source / drain.

[0359] The flexible display device may further include a light shielding pattern disposed under the active layer, wherein the connection member may be made of a conductive material constituting the light shielding pattern and located on the same layer as the light shielding pattern.

[0360] The flexible display device may further include a pad disposed on the substrate in the non-display area.

[0361] The connection member may have a quadrangular frame shape and be disposed at three sides of the non-display area except for a lower portion.

[0362] The connection member may extend to the pad at the lower portion of the non-display area, thereby being electrically connected to the pad.

[0363] The conductive layer may overlap a portion of the display area and the non-display area in a quadrangular frame shape.

[0364] The conductive layer may be made of a doped layer in the contact hole.

[0365] The conductive layer may be made of a doped layer in the second buffer layer.

[0366] The contact hole may be provided in the first buffer layer and the substrate to expose the conductive layer of the second buffer layer.

[0367] The connection member may be made of a second electrode of the light emitting element.

[0368] The second electrode may extend to the non-display area to overlap a portion of the conductive layer.

[0369] The connection member may overlap a portion of the non-display area and the display area in a rectangular shape.

[0370] The second buffer layer may be composed of a second upper buffer layer and a second lower buffer layer, wherein the conductive layer may be made of a metal layer disposed between the second upper buffer layer and the second lower buffer layer.

[0371] According to another aspect of the present disclosure, a flexible display device is provided. The flexible display device includes: a substrate divided into a display area and a non-display area; a first buffer layer disposed above the substrate; a second buffer layer disposed below the substrate; a support member disposed below the second buffer layer; a transistor and a light-emitting element disposed above the first buffer layer in the display area; a conductive layer disposed in the second buffer layer in the non-display area; and a connecting member connected to the conductive layer through a contact hole, wherein the substrate is made of polyimide, and the connecting member removes charges accumulated in the polyimide substrate by grounding.

[0372] Although the exemplary embodiments of the present disclosure have been described in detail with reference to the accompanying drawings, the present disclosure is not limited thereto, and the present disclosure can be implemented in many different forms without departing from the technical concept of the present disclosure. Therefore, the exemplary embodiments of the present disclosure are provided for illustrative purposes only and are not intended to limit the technical concept of the present disclosure. The scope of the technical concept of the present disclosure is not limited thereto. Therefore, it should be understood that the above exemplary embodiments are exemplary in all aspects and do not limit the present disclosure. The scope of protection of the present disclosure should be interpreted based on the attached claims, and all technical concepts within their equivalent scope should be interpreted as falling within the scope of the present disclosure.

Claims

1. A flexible display device, comprising: A substrate, divided into a display area and a non-display area; A first buffer layer is disposed above the substrate; A second buffer layer is disposed below the substrate; A supporting member, disposed below the second buffer layer; A transistor and a light-emitting element, arranged above the first buffer layer in the display area; a conductive layer, disposed in the second buffer layer in the non-display area; and a connecting member disposed on the first buffer layer in the non-display area and electrically connected to the conductive layer through a contact hole, The substrate is made of polyimide, and the connecting member removes charges accumulated in the polyimide substrate by grounding. 2 . The flexible display device according to claim 1 , wherein the supporting member is made of etched glass.

3. The flexible display device according to claim 1, wherein the supporting member comprises: an auxiliary substrate made of polyimide; and A protective film is provided below the auxiliary substrate.

4. The flexible display device according to claim 1, wherein the transistor comprises a gate electrode, an active layer, a source electrode and a drain electrode, The connecting member is made of a conductive material constituting the gate or the source / drain, and is located on the same layer as the gate or the source / drain.

5. The flexible display device according to claim 1, further comprising: A light shielding pattern is arranged below the active layer of the transistor, The connecting member is made of a conductive material constituting the light shielding pattern and is located on the same layer as the light shielding pattern.

6. The flexible display device according to claim 1, further comprising: A pad is disposed on the substrate in the non-display area. 7 . The flexible display device of claim 6 , wherein the connection member has a quadrangular frame shape and is disposed at three sides of the non-display area except for a lower portion. 8 . The flexible display device of claim 7 , wherein the connection member extends to the pad at the lower portion of the non-display area, thereby being electrically connected to the pad. 9 . The flexible display device of claim 1 , wherein the conductive layer overlaps a portion of the display area and the non-display area in a quadrangular frame shape. 10 . The flexible display device according to claim 1 , wherein the conductive layer is made of a doped layer in the contact hole. 11 . The flexible display device according to claim 1 , wherein the conductive layer is made of a doped layer in the second buffer layer. 12 . The flexible display device of claim 1 , wherein the contact hole is provided in the first buffer layer and the substrate to expose the conductive layer of the second buffer layer. 13 . The flexible display device according to claim 1 , wherein the connection member is made of a second electrode of the light emitting element. 14 . The flexible display device of claim 13 , wherein the second electrode extends to the non-display area to overlap a portion of the conductive layer. 15 . The flexible display device of claim 13 , wherein the connection member overlaps a portion of the non-display area and the display area in a rectangular shape.

16. The flexible display device according to claim 1, wherein the second buffer layer consists of a second upper buffer layer and a second lower buffer layer, The conductive layer is made of a metal layer disposed between the second upper buffer layer and the second lower buffer layer.

17. A flexible display device, comprising: A substrate, divided into a display area and a non-display area; A first buffer layer is disposed above the substrate; A second buffer layer is disposed below the substrate; A supporting member, disposed below the second buffer layer; A transistor and a light-emitting element, arranged above the first buffer layer in the display area; A conductive layer, disposed in the second buffer layer in the non-display area; and a connecting member connected to the conductive layer through a contact hole, The substrate is made of polyimide, and the connecting member removes charges accumulated in the polyimide substrate by grounding.

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