Flexible display device

Abstract

A flexible display device is disclosed. A flexible display device with enhanced reliability is disclosed. The flexible display device includes: a flexible substrate including a plurality of display areas and a bending area between the plurality of display areas; a display unit disposed in the plurality of display areas and the bending area of the flexible substrate; a cover film which covers the display unit; and a support member including a plurality of support members that respectively support the plurality of display regions and an elastic portion that supports the bending portion. The plurality of support members and the elastic portion include different materials, and a boundary surface between each of the plurality of support members and the elastic portion has a concave curved shape or a shape inclined at a specific angle.

Description

[0001] This application is a divisional application of the invention patent application with the original application number 201910572320.7 (filing date: June 28, 2019, invention title: Flexible display device). Technical Field

[0002] The present disclosure relates to a flexible display device. Background Art

[0003] Generally, display devices are widely used as display screens of various electronic devices. For example, mobile communication terminals, electronic notepads, e-books, portable multimedia players (PMPs), navigation devices, ultra-mobile personal computers (UMPCs), mobile phones, smart phones, tablet computers, watch phones, electronic tablets, wearable devices, portable information devices, automotive control display devices, televisions, laptop computers, monitors, etc.

[0004] Among display devices, liquid crystal display (LCD) devices, light-emitting display devices, and electrophoretic display devices can be made thinner. Therefore, research and development are underway to implement a display device as a flexible display device. In a flexible display device, lines and a display unit including thin film transistors (TFTs) are provided on a flexible substrate having flexibility, and an image can be displayed even when bent like paper. Therefore, flexible display devices can be applied to various display fields.

[0005] Recently, a rollable display device or a foldable display device each utilizes the advantage of being able to bend or fold of a flexible display device, and can provide a large-screen display unit while maintaining portability, and thus has received wide attention as a next-generation display device. Summary of the Invention

[0006] Accordingly, the present disclosure aims to provide a flexible display device that substantially eliminates one or more problems caused by limitations and disadvantages of the prior art.

[0007] The inventors have recognized that in the case of manufacturing a flexible display panel by forming a flexible substrate on a carrier glass, completing the manufacturing process of the flexible display panel, and detaching (or separating) the carrier glass from the flexible substrate by using a laser beam through a release process, the manufacturing cost increases due to the use of expensive laser equipment, and defects (particles or transfer caused by the surface roughness of the flexible substrate) occur due to the laser release process. In addition, the inventors have recognized that since the rear protective film (or backplane) is attached to the rear surface of the flexible substrate, the bending reliability of the flexible display panel is reduced due to the bending stress applied to the bending area of the flexible display panel via the rear protective film. Therefore, the inventors have continuously studied and developed technologies for replacing the laser release process, and have studied technologies for ensuring the bending reliability of the flexible display panel through a manufacturing process without the laser release process. Therefore, a flexible display device with a new structure having enhanced reliability has been invented.

[0008] One aspect of the present disclosure is directed to providing a flexible display device having enhanced reliability.

[0009] The objects of the present disclosure are not limited to the foregoing, and other objects not described herein will be clearly understood by those skilled in the art from the following description.

[0010] Other advantages and features of the present disclosure will be partly set forth in the following description, and partly will become apparent to those of ordinary skill in the art after studying the following, or can be learned from the practice of the present disclosure. The objects and other advantages of the present disclosure can be achieved and obtained by the structures particularly pointed out in the written description and its claims, as well as the drawings.

[0011] To achieve these and other advantages and in accordance with the purpose of the present disclosure, as embodied and broadly described herein, there is provided a flexible display device including: a flexible substrate including a plurality of display regions and a bending region between the plurality of display regions; a display unit disposed in the plurality of display regions and the bending region of the flexible substrate; a cover film covering the display unit; and a support member including a plurality of support parts respectively supporting the plurality of display regions and an elastic part supporting the bending part, wherein the plurality of support parts and the elastic part include different materials, and a boundary surface between each of the plurality of support parts and the elastic part has a concave bending shape or a shape inclined at a specific angle.

[0012] In another embodiment of the present disclosure, a flexible display device is provided, which includes: a flexible substrate including a plurality of display regions and a bending region between the plurality of display regions; a display unit disposed in the plurality of display regions and the bending region of the flexible substrate; a cover film covering the display unit; and a glass substrate including an opening portion disposed on the rear surface of the flexible substrate to overlap with the bending region, wherein the opening portion includes an inclined surface having a bent shape.

[0013] The flexible display device according to the present disclosure can even be manufactured without a laser release process, and can improve bending reliability and reliability of preventing water or oxygen from infiltrating.

[0014] It should be understood that the foregoing general description and the following detailed description of the present disclosure are both exemplary and explanatory, and are intended to provide further explanation of the claimed present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings are included to provide a further understanding of the present disclosure and are incorporated into and constitute a part of this application. The drawings illustrate embodiments of the present disclosure and, together with the description, are used to explain the principles of the present disclosure. In the drawings:

[0016] Figure 1 is a perspective view showing a flexible display device according to an embodiment of the present disclosure;

[0017] Figure 2 is a cross-sectional view taken along line I-I' shown in Figure 1 ;

[0018] Figure 3 is a cross-sectional view for describing an inner bending structure of a flexible display device according to an embodiment of the present disclosure;

[0019] Figure 4 is a cross-sectional view for describing an inner bending structure of a flexible display device according to an embodiment of the present disclosure;

[0020] Figure 5A , Figure 5B and Figure 5C are cross-sectional views for describing various examples of an opening portion in a flexible display device according to an embodiment of the present disclosure;

[0021] Figure 6 is a diagram for describing bending stresses of a bending region and a filler of a flexible display device according to an embodiment of the present disclosure.

[0022] Figure 7A , Figure 7B and Figure 7CFIG. is for describing various structures of fillers of a flexible display device according to an embodiment of the present disclosure;

[0023] Figure 8 FIG. is a cross-sectional view of a flexible display device according to another embodiment of the present disclosure;

[0024] Figure 9A FIG. is a diagram showing an inner winding structure of a flexible display device according to another embodiment of the present disclosure;

[0025] Figure 9B FIG. is a diagram showing an outer winding structure of a flexible display device according to another embodiment of the present disclosure;

[0026] Figure 10A 、 Figure 10B 、 Figure 10C and Figure 10D FIG. is a micrograph showing the shape of an opening portion based on glass etching in a flexible display device according to an embodiment of the present invention;

[0027] Figure 11 FIG. is a perspective view of a flexible display device according to another embodiment of the present disclosure;

[0028] Figure 12 is a cross-sectional view taken along the line II-II' shown in Figure 11 ;

[0029] Figure 13 FIG. is a perspective view of a flexible display device according to another embodiment of the present disclosure;

[0030] Figure 14 is a cross-sectional view taken along the line III-III' shown in Figure 11 ;

[0031] Figure 15 FIG. is a plan view showing the Figure 13 pattern frame shown in;

[0032] Figure 16 FIG. is a perspective view of a flexible display device according to another embodiment of the present disclosure;

[0033] Figure 17 is a cross-sectional view taken along the line IV-IV' shown in Figure 16 ; and

[0034] Figure 18 FIG. is a perspective view of a flexible display device according to another embodiment of the present disclosure;

[0035] Figure 19 is a cross-sectional view taken along the line V-V' shown in Figure 18 ; and

[0036] Figure 20 It is a micrograph showing the shape of the opening portion based on the glass etching process in the flexible display panel according to the experimental example of the present disclosure based on the over-etching situation. Detailed implementation manners

[0037] Exemplary implementation manners of the present disclosure will now be described in detail, and examples of the implementation manners are shown in the drawings. As long as possible, the same reference numerals will be used throughout the drawings to represent the same or similar components.

[0038] Through the following implementation manners described with reference to the drawings, the advantages and features of the present disclosure and the methods for realizing them will be clarified. However, the present disclosure can be implemented in different forms and should not be construed as limited to the implementation manners set forth herein. On the contrary, these implementation manners are provided to make the present disclosure thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art. In addition, the present disclosure is only defined by the scope of the claims.

[0039] The shapes, sizes, ratios, angles, and quantities disclosed in the drawings for describing the implementation manners of the present disclosure are merely examples, and thus, the present disclosure is not limited to the details shown. The same reference numerals always represent the same elements. In the following description, when it is determined that the detailed description of the relevant known technology will unnecessarily obscure the key points of the present disclosure, the detailed description thereof will be omitted.

[0040] In cases where "including", "having", and "containing" described in this specification are used, another component can be added unless "only" is used. Unless otherwise stated, terms in the singular form can include the plural form.

[0041] When interpreting elements, although not explicitly described, the elements are interpreted as including an error range.

[0042] When describing positional relationships, for example, when the positional relationship between two components is described as "on...", "above...", "below...", and "next to...", one or more other components can be provided between the two components unless "exactly" or "directly" is used.

[0043] When describing temporal relationships, for example, when the time sequence is described as "after...", "subsequent to...", "next", and "before...", discontinuous cases can be included unless "exactly" or "directly" is used.

[0044] It should be understood that although terms such as "first" and "second" may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of the present disclosure.

[0045] The term "at least one" should be understood to include any and all combinations of one or more of the associated listed items. For example, the meaning of "at least one of the first item, the second item, and the third item" represents all combinations of two or more items selected from the first item, the second item, or the third item, as well as the first item, the second item, or the third item.

[0046] As can be fully understood by those skilled in the art, the features of various embodiments of the present disclosure can be partially or wholly coupled or combined with each other, and can operate differently from each other and be technically driven. The embodiments of the present disclosure can be executed independently of each other, or can be executed together in a mutually dependent relationship.

[0047] Hereinafter, embodiments of a display device according to the present disclosure will be described in detail with reference to the accompanying drawings. When adding reference numerals to the elements of each drawing, although the same elements are shown in other drawings, the same reference numerals may refer to the same elements. Additionally, for ease of description, the scale of each element shown in the drawings is different from the actual scale, and thus, is not limited to the scale shown in the drawings.

[0048] Figure 1 is a perspective view showing a flexible display device 10 according to an embodiment of the present disclosure, Figure 2 is a cross-sectional view taken along line I-I' shown in Figure 1 .

[0049] Referring to Figure 1 and Figure 2 , a flexible display device 10 according to an embodiment of the present disclosure may include a flexible display panel 100 and a panel driving circuit 200.

[0050] The flexible display panel 100 may be a flexible light-emitting display panel, a flexible organic light-emitting display panel, a flexible liquid crystal display panel, a flexible electrophoretic display panel, a flexible electro-wetting display panel, a flexible micro light-emitting diode display panel, or a flexible quantum dot light-emitting display panel. Hereinafter, an example in which the flexible display panel 100 is a flexible organic light-emitting display panel will be described in detail.

[0051] The flexible display panel 100 according to the present disclosure may include a plurality of display regions DA and a bending region BA between the plurality of display regions DA. According to the bending of the bending region BA, the flexible display panel 100 can be folded into a certain radius of curvature.

[0052] The flexible display panel 100 according to an embodiment may include a first display area DA1, a second display area DA2, and a bending area BA. For example, with respect to the length direction X of the flexible display panel 100, the first display area DA1 may be disposed on one side (or the left area) of the flexible display panel 100, the second display area DA2 may be disposed on the other side (or the right area) of the flexible display panel 100, and a bending area BA may be disposed between the first display area DA1 and the second display area DA2. Here, the width of the bending area BA may be set based on the radius of curvature of the flexible display panel 100 folded into a bent shape. Moreover, the bending area BA may display an image corresponding to one frame together with the first display area DA1 and the second display area DA2 on one screen, and may be referred to as a bent display area.

[0053] The flexible display panel 100 according to an embodiment may include a glass substrate 110, a flexible substrate 130, a display unit 150, and a cover film 170.

[0054] The glass substrate 110 (or the support member) may include a glass material. The glass substrate 110 according to an embodiment may have a thickness of about 0.01 mm to 1.0 mm in order to maintain the flatness of the flexible substrate 130 or prevent oxygen or water from penetrating into the flexible display panel 100, but is not limited thereto, and may have a thickness that varies based on the size of the flexible display device 10. According to another embodiment, the glass substrate 110 may have a thickness of about 0.01 mm to 0.7 mm so as to prevent oxygen or water from penetrating into the flexible display panel 100 and facilitate bending of the flexible substrate 130, but is not limited thereto and may have a thickness that varies based on the size of the flexible display device 10.

[0055] The glass substrate 110 may include an opening portion OP that is coupled to the rear surface of the flexible substrate 130 to overlap with the bending area BA. That is, the glass substrate 110 according to an embodiment may include a plurality of support members 111 and 113 and an opening portion OP.

[0056] Each of the plurality of support members 111 and 113 may support the rear surface of the flexible substrate 130 that overlaps with each of the plurality of display areas DA1 and DA2, and may include an inclined surface IP having a bent shape facing the opening portion OP. The support member 111 may maintain the flatness of the first display area DA1 and may bend together with the first display area DA1 based on its thickness, and the support member 113 may maintain the flatness of the second display area DA2 and may bend together with the second display area DA2 based on its thickness.

[0057] The opening portion OP can be provided between the plurality of support members 111 and 113 to overlap with the bending region BA. The opening portion OP can enable the bending region BA to bend smoothly. In particular, the opening portion OP can reduce the bending stress including the compressive stress and the tensile stress applied to the bending region BA when the bending region BA bends.

[0058] According to one embodiment, the opening portion OP can be formed by etching (or patterning) from the plate-shaped glass substrate 110 in a glass etching process performed after the process of manufacturing the flexible display panel 100 is completed. Therefore, the opening portion OP can include an inclined surface IP having a curved shape. For example, the glass etching process can be a wet etching process using an etchant including hydrofluoric acid (HF).

[0059] Optionally, the opening portion OP can be formed by a laser patterning process instead of a glass etching process. However, in this case, there is a problem of using expensive laser equipment, and since the opening portion OP includes a substantially vertical cutting surface, there are problems of a grinding process and a laser patterning process that need to be performed on the cutting surface respectively and a cleaning process for removing glass chips (or fragments) generated in the grinding process. On the other hand, the opening portion OP based on the glass etching process can have an inclined surface with a curved shape based on the etching process conditions, and thus, no additional grinding process and cleaning process are required.

[0060] The flexible substrate 130 can include a plastic material that can be bent to bend the bending region BA into a bent shape. For example, the flexible substrate 130 can include one material among polyimide (PI), polycarbonate (PC), polyethylene terephthalate (PET), polymethylpentene (PMP), polymethyl methacrylate (PMMA), polynorborneen (PNB), polyethylene naphthalate (PEN), polyethersulfone (PES), and cycloolefin copolymer (COS), and for example, can include an opaque or colored polyimide material.

[0061] The flexible substrate 130 according to the present disclosure can be formed by curing a plastic material coated on the front surface of the plate-shaped glass substrate 110 without an opening portion OP in a certain thickness. Accordingly, the glass substrate 110 can be directly coupled to (or in contact with) the rear surface of the flexible substrate 130. In other words, the flexible substrate 130 can be directly (or physically) coupled to the front surface of the glass substrate 110 without an intermediate layer such as an adhesive layer. Accordingly, in the present disclosure, even after the process of manufacturing the flexible display panel 100 is completed, the support members 111 and 113 of the glass substrate 110 can be maintained without being separated from the rear surface of the flexible substrate 130. Accordingly, a laser release process of separating the entire glass substrate 110 from the flexible substrate 130 can be omitted. In the present disclosure, since the flexible display panel 100 can be manufactured even without using expensive laser equipment, the manufacturing cost of the flexible display panel can be reduced, defects (particles or transfer caused by surface roughness of the flexible substrate) caused by the laser release process can be prevented from occurring, and a rear protective film attached to the rear surface of the flexible substrate 130 can be omitted, thereby improving the bending reliability of the flexible substrate 130.

[0062] The display unit 150 may be disposed in a plurality of display areas DA and bending areas BA respectively defined on the flexible substrate 130. The display unit 150 may be referred to as a pixel array component.

[0063] The display unit 150 according to an embodiment may include a pixel array layer 151 and a encapsulation layer 153.

[0064] The pixel array layer 151 may include a plurality of pixels respectively disposed in a plurality of pixel areas defined by a plurality of pixel driving lines provided in the bending area BA and the plurality of display areas of the flexible substrate 130, and display an image according to signals provided through the plurality of pixel driving lines. Here, the pixel driving lines may include a plurality of data lines, a plurality of gate lines, and a pixel driving power supply.

[0065] Each of the plurality of pixels may include a pixel circuit layer, an anode layer, a self-emitting device layer, and a cathode layer.

[0066] The pixel circuit layer can be disposed in the transistor region of each pixel region and can be driven based on signals provided through the pixel driving lines to control the light emission of the self-emitting device layer. The pixel circuit layer according to an embodiment may include at least two thin film transistors (TFTs) and at least one capacitor, and the at least two thin film transistors include driving TFTs disposed in the transistor region of each pixel region defined on the flexible substrate 130. Here, the pixel circuit layer may include at least one of amorphous silicon (a-Si) TFTs, polysilicon TFTs, oxide TFTs, and organic TFTs. The pixel circuit layer may be covered by a cover layer on the flexible substrate 130 to have a relatively thick thickness.

[0067] The anode layer can be disposed on the cover layer overlapping the opening region defined in each pixel region and can be electrically connected to the source electrode of the driving TFT through an electrode contact hole provided in the cover layer. Here, the opening region of each pixel region can be defined by a bank pattern provided on the cover layer to cover the edge of the anode layer.

[0068] The self-emitting device layer can be disposed on the anode layer disposed in the opening region of each pixel among a plurality of pixels. The self-emitting layer according to an embodiment may include an organic light-emitting device, a quantum dot light-emitting device, or an inorganic light-emitting device. For example, the self-emitting device layer can be disposed in a structure in which a hole injection layer, a hole transport layer, an organic light-emitting layer, an electron transport layer, and an electron injection layer are sequentially stacked. Here, one or two or more of the hole injection layer, the hole transport layer, the electron transport layer, and the electron injection layer can be omitted. The organic light-emitting layer can be configured to emit light of the same color (e.g., white light) for each pixel, and can be configured to emit light of different colors (e.g., red light, green light, or blue light) for each pixel.

[0069] The cathode layer can be disposed on the flexible substrate 130 and can be commonly connected to the self-emitting device layer disposed in each pixel region. The cathode layer may be referred to as a common layer.

[0070] The encapsulation layer 153 can be disposed on the flexible substrate 130 to surround the pixel array layer 151. The encapsulation layer 153 can protect the pixel array layer 151 and the like from external impact and can prevent oxygen, water, and / or particles from penetrating into the self-emitting device layer.

[0071] According to one embodiment, the encapsulation layer 153 may include at least one inorganic layer. Moreover, the encapsulation layer 153 may further include at least one organic layer. For example, the encapsulation layer 153 may include a first inorganic encapsulation layer, an organic encapsulation layer, and a second inorganic encapsulation layer. Each of the first encapsulation layer and the second encapsulation layer may include an inorganic material such as silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiON), titanium oxide (TiOx), and aluminum oxide (AlOx). In addition, the organic encapsulation layer may include an organic material such as an acrylic resin, an epoxy resin, a phenolic resin, a polyamide resin, a polyimide resin, and a benzocyclobutene resin. The organic encapsulation layer may be referred to as a particle covering layer.

[0072] In addition, the flexible substrate 130 may further include a pad member and a gate driving circuit unit.

[0073] The pad member may include a plurality of pad electrodes provided at at least one edge of the flexible substrate 130. The plurality of pad electrodes may be respectively connected to pixel driving lines provided in the display unit 150 through a plurality of connection lines, and may be electrically connected to the gate driving circuit unit. The pad member may be connected to the panel driving circuit 200, and may provide signals provided by the panel driving circuit 200 to the gate driving circuit unit and pixel driving lines provided in the display unit 150 through a plurality of connection lines.

[0074] The gate driving circuit unit may be provided at the left edge and / or the right edge of the flexible substrate 130, and may be connected to one end and / or the other end of each of a plurality of gate lines. In response to a gate control signal provided through the pad member, the gate driving circuit unit may generate a gate control signal, and may provide the generated gate control signal to each of the plurality of gate lines. The gate driving circuit unit may be a gate embedded circuit formed together with the process of manufacturing the TFTs of each pixel, but is not limited thereto.

[0075] The cover film 170 may include a flexible film as thin and transparent as plastic. The cover film 170 may be attached to the encapsulation layer 153 to cover the display unit 150 except for the pad member provided on the flexible substrate 130. The cover film 170 may be attached to the upper surface of the encapsulation layer 153 through an optical adhesive member. The cover film 170 may be provided in the outermost part of the flexible display panel 100, and may protect the display unit 150 from external impact.

[0076] In addition, the flexible display panel 100 according to an embodiment of the present disclosure may further include a barrier layer, a touch sensor layer, and a polarization layer.

[0077] The barrier layer may be disposed on the upper surface of the encapsulation layer 153 and may prevent water from penetrating into the flexible display panel 100. The barrier layer may include a material with a low water vapor transmission rate (e.g., a polymer material).

[0078] The touch sensor layer may be disposed between the barrier layer and the encapsulation layer 153 or may be disposed on the barrier layer. The touch sensor layer may include mutual capacitance or self-capacitance touch sensors or touch electrodes whose capacitance changes based on user touch.

[0079] The polarization layer may be disposed on the touch sensor layer or the barrier layer and may polarize the light emitted from each pixel or may prevent reflection of external light, thereby enhancing the optical characteristics of the flexible display panel 100. For example, the polarization layer may change the light reflected by the lines and / or thin film transistors (TFTs) provided in each pixel to a circularly polarized state to enhance the visibility and contrast of the flexible display device. For example, the polarization layer according to one embodiment may include a circular polarizer. Optionally, the polarization layer may be provided as a film type including a circular polarizer and may be attached to the touch sensor layer or the barrier layer by an adhesive.

[0080] In addition, the flexible display panel 100 according to an embodiment of the present disclosure may further include a wavelength conversion layer. When the flexible display panel 100 includes a wavelength conversion layer, the self-emitting device layer may be configured to emit white light.

[0081] The wavelength conversion layer may be disposed between the encapsulation layer 153 and the cover film 170. The wavelength conversion layer may change the wavelength of the light emitted from each pixel. For example, the wavelength conversion layer may be disposed in the encapsulation layer 153, between the encapsulation layer 153 and the barrier layer, between the encapsulation layer 153 and the polarization layer, between the barrier layer and the polarization layer, or between the barrier layer (or polarization layer) and the cover film 170 to overlap with the opening area of each pixel.

[0082] The wavelength conversion layer according to one embodiment may include a color filter that transmits only the wavelength corresponding to the color set in each pixel of the light emitted from the self-emitting device layer to the cover film 170. For example, the wavelength conversion layer may transmit only the wavelengths of red, green, or blue light. For example, in the flexible display device according to the present disclosure, when a unit pixel includes first to third pixels adjacent to each other, the wavelength conversion layer provided in the first pixel may include a red color filter, the wavelength conversion layer provided in the second pixel may include a green color filter, and the wavelength conversion layer provided in the third pixel may include a blue color filter. In addition, in the flexible display device according to the present disclosure, a unit pixel may further include a white pixel in which the wavelength conversion layer is not provided.

[0083] According to another embodiment, the wavelength conversion layer may include quantum dots having dimensions that re-emit light based on light emitted from the self-luminous device layer to the cover film 170 to emit light of the color set in each pixel. Here, the quantum dots may be selected from CdS, CdSe, CdTe, CdZnSeS, ZnS, ZnSe, GaAs, GaP, GaAs-P, Ga-Sb, InAs, InP, InSb, AlAs, AlP, and AlSb. For example, the wavelength conversion layer of the first pixel may include quantum dots such as CdSe or InP, the wavelength conversion layer of the second pixel may include quantum dots such as CdZnSeS, and the wavelength conversion layer of the third pixel may include quantum dots such as ZnSe. Accordingly, a flexible display device including quantum dots in the wavelength conversion layer may have a high color reproduction rate.

[0084] According to another embodiment, the wavelength conversion layer may include a color filter containing quantum dots.

[0085] Optionally, the encapsulation layer 153 may be changed to a surface seal surrounding the pixel array layer 151, and in this case, the cover film 170 may be coupled to the pixel array layer 151 through the surface seal.

[0086] The panel driving circuit 200 may be connected to pad components provided on the flexible substrate 130 and may provide signals for displaying an image on the display unit 150. The panel driving circuit 200 according to one embodiment may include a flexible circuit film 210 and a driving integrated circuit (IC) 230.

[0087] The flexible circuit film 210 may be attached to the pad components on the flexible substrate 130 through a film attachment process.

[0088] The driving IC 230 may be mounted on the flexible circuit film 210 through a chip bonding process or a surface mounting process. The driving IC 230 may generate a data signal and a gate control signal based on video data and a timing synchronization signal provided by an external display driving system, provide the data signal to the data lines of each pixel through the pad components, and provide the gate control signal to the gate driving circuit unit.

[0089] Optionally, the driving IC 230 may be mounted on the flexible substrate 130 without being mounted on the flexible circuit film 210 and may be electrically connected to the pad components, the gate driving circuit unit, and the pixel driving signal lines provided in the display unit 150. In this case, the flexible circuit film 210 may transmit signals between the pad components and the display driving system.

[0090] The flexible display panel 100 according to one embodiment may further include a demultiplexer disposed on the flexible substrate 130. The demultiplexer circuit may be disposed between a plurality of data lines and the driving IC 230, and may sequentially provide two or more data lines having data signals time-division output through the output channels of the driving IC 230. When the flexible display panel 100 includes a demultiplexer circuit, the flexible display device 10 according to the present disclosure may reduce the number of output channels of the driving IC 230.

[0091] The flexible display device 10 according to an embodiment of the present disclosure may further include a filler 190 (or an elastic part).

[0092] The filler 190 may be filled (or buried) into the opening part OP provided on the glass substrate 110 of the flexible display panel 100. The filler 190 may prevent water or oxygen from penetrating into the flexible substrate 130 through the opening part OP. In addition, when the flexible display panel 100 is repeatedly bent (or folded), the filler 190 may prevent the portion between the flexible substrate 310 and the glass substrate 110 adjacent to the opening part OP from being separated. The opening part OP filled with the filler 190 may be defined as an elastic part of the glass substrate 110. In this case, the glass substrate 110 may include a plurality of support members and an elastic part connected between the plurality of support members. In this case, the support members and the elastic part may be formed of different materials, and the boundary surface between the elastic part and each support member may have a concave curved shape or an inclined shape inclined at a certain angle.

[0093] The filler 190 may be disposed in the opening part OP overlapping with the bending area BA of the flexible display panel 100. Therefore, when the bending area BA of the flexible display panel 100 is bent (or folded), the shape based on the width and thickness of the filler 190 may be set based on the compressive stress and tensile stress applied to the bending area BA of the flexible display panel 100 based on the position of the neutral plane.

[0094] A liquid resin (e.g., an organic resin) may be filled (or buried) into the opening part OP through a spraying process or a dispensing process, and then, by curing the liquid resin through a photo-curing process, the filler 190 according to the embodiment may be formed. Since the filler 190 may include a liquid resin, it may be filled (or infiltrated) into the gap between the flexible substrate 130 and the glass substrate 110 adjacent to the opening part OP. For this purpose, the filler 190 may include a material having adhesive properties and moisture-proof properties, and may include an optical adhesive cured by ultraviolet rays (UV). For example, the filler 190 may include an acrylic-based or silicone-based organic adhesive material. Moreover, the filler 190 may have an elongation rate of 600% or more.

[0095] Instead of using a filler 190 including a liquid resin, an adhesive may be used to attach the flexible film to the opening portion OP through a lamination process. However, the lamination process performed on the flexible film may require an alignment device for precise alignment, resulting in a reduction in productivity. Moreover, a gap may occur between the flexible film attached to the opening portion OP and the glass substrate 110, and the reliability of the flexible display panel may be reduced due to water or oxygen passing through the gap.

[0096] The flexible display device 10 according to an embodiment of the present disclosure may include a glass substrate 110 including an opening portion OP overlapping the bending region BA of the flexible display panel 100. Thus, the glass substrate 110 can improve the reliability of preventing water or oxygen from infiltrating, and the opening portion OP can reduce the bending stress applied to the bending region BA of the flexible display panel 100, thereby improving the bending reliability. In addition, the flexible display device 10 according to an embodiment of the present disclosure may further include a filler 190 filled into the opening portion OP of the glass substrate 110. Thus, a reduction in the bending reliability of the flexible display panel 100 can be prevented or minimized, and the reliability of preventing water or oxygen from infiltrating can be further improved.

[0097] Therefore, even without a laser release process, the flexible display device 10 according to an embodiment of the present disclosure can be manufactured. Thus, the reliability of preventing water or oxygen from infiltrating and the bending reliability can be improved. In addition, according to the present disclosure, the laser release process of separating the entire glass substrate 110 from the flexible substrate 130, the rear protective film attached to the rear surface of the flexible substrate 130, and the attachment process performed on the rear protective film can be omitted, thereby improving productivity.

[0098] Figure 3 is a cross-sectional view for describing an inner bending structure of a flexible display device according to an embodiment of the present disclosure.

[0099] Referring to Figures 1 to 3 , in the flexible display device 10 according to an embodiment of the present disclosure, the flexible substrate 130 may be bent into an inner bending type in which a plurality of display regions DA1 and DA2 face each other. That is, the flexible display panel 100 unfolded in a planar state may be folded in a direction in which the plurality of display regions DA1 and DA2 directly face each other according to the bending of the bending region BA. In this case, the glass substrate 110 may be disposed in the outermost portion of the folded flexible display panel 100. Thus, the display unit 150 (or screen) may not be exposed to the outside. Accordingly, the glass substrate 110 and the like can protect the display unit 150 from external impact.

[0100] Figure 4It is a cross-sectional view for describing an outer bending structure of a flexible display device according to an embodiment of the present disclosure.

[0101] Referring to Figure 1 and Figure 4 in the flexible display device 10 according to an embodiment of the present disclosure, the flexible substrate 130 can be bent into an outer bending type in which the support members 111 and 113 of the flexible substrate 130 face each other. That is, the flexible display panel 100 unfolded in a planar state can be folded in a direction in which the support members 111 and 113 of the flexible substrate 130 directly face each other according to the bending of the bending region BA. In this case, the cover film 170 can be disposed in the outermost part of the folded flexible display panel 100, and thus, the display unit 150 (or screen) can be exposed to the outside, whereby the flexible display panel 100 can display an image on the display unit 150 even in a folded state.

[0102] Figure 5A 、 Figure 5B and Figure 5C They are cross-sectional views for describing various examples of an opening part in a flexible display device according to an embodiment of the present disclosure.

[0103] Referring to Figure 5A the opening part OP according to the first embodiment of the present disclosure can be formed by a glass etching process based on a soft etching condition. Here, the soft etching condition can be defined as a glass etching process that is performed for a time shorter than a predetermined reference etching time to etch glass to a certain thickness.

[0104] A mask pattern MP can be formed on the rear surface 110a of the glass substrate 110 that overlaps with the plurality of display regions DA1 and DA2 except for the bending region BA, and then, the opening part OP according to the first embodiment can be etched by a glass etching process using the mask pattern MP as a mask to form an area of the inclined glass substrate 110 that overlaps with the bending region BA in an inclined shape based on the soft etching condition.

[0105] The opening part OP according to the first embodiment may include an inclined surface IP having a concave bending shape. In this case, the cross-sectional area of the opening part OP parallel to the rear surface 130a of the flexible substrate 130 can increase in a direction away from the rear surface 130a of the flexible substrate 130. For example, the cross-sectional area of the opening part OP can be defined as the size of a horizontal cutting surface cut with respect to a horizontal surface parallel to the rear surface 130a of the flexible substrate 130. The first angle "θ1" between the inclined surface IP of the opening part OP and the rear surface 130a of the flexible substrate 130 can be an acute angle, and as an example, can be less than 15 degrees.

[0106] For ease of description, the inclined surface IP shown in Figure 5A is conceptually shown. Therefore, the first angle “θ1” is not limited to the angle between the inclined surface IP of the opening portion OP shown in Figure 5A and the rear surface 130a of the flexible substrate 130, respectively.

[0107] The inclined surface IP of the opening portion OP according to the first embodiment may include a tail portion formed by a glass etching process based on a soft etching condition, and thus overlaps with the bending region BA. Since the etching process time is shorter than the reference etching time, the portion of the glass substrate 110 that contacts the boundary portion BP between the bending region BA and the display region DA is not completely removed. Therefore, the tail portion TP may be defined as a non-etched portion, and the thickness of the non-etched portion gradually thins in the direction from the boundary portion BP between the bending region BA and the display region DA to the middle portion of the bending region BA. When the bending region BA is bent, the tail portion TP provided in the inclined surface IP of the opening portion OP may break off from the inclined surface IP, resulting in particle defects or causing scratches or cracks in the flexible substrate 130.

[0108] Referring to Figure 5B , the opening portion OP according to the second embodiment of the present disclosure may be formed by a glass etching process based on a just-etching condition. Here, the just-etching condition may be defined as a glass etching process that performs a predetermined reference etching time to etch the glass by a certain thickness.

[0109] The mask pattern MP may be formed on the rear surface 110a of the glass substrate 110 that overlaps with the plurality of display regions DA1 and DA2 except for the bending region BA. Then, the opening portion OP according to the second embodiment may be formed by etching the region of the glass substrate 110 having a concave cross-sectional shape and overlapping with the bending region BA using the mask pattern MP as a mask based on the just-etching condition through a glass etching process.

[0110] The opening portion OP according to the second embodiment may include an inclined surface IP having a concave bending shape. In this case, the cross-sectional area of the opening portion OP parallel to the rear surface 130a of the flexible substrate 130 may increase in the direction away from the rear surface 130a of the flexible substrate 130. The second angle “θ2” between the inclined surface IP of the opening portion OP and the rear surface 130a of the flexible substrate 130 may be an acute angle, and as an example, may be 15 degrees to 70 degrees.

[0111] According to the second embodiment, the inclined surface IP of the opening portion OP can be formed by a glass etching process based on an appropriate etching condition. Thus, it may include a concave curved shape between one end IPa overlapping with the boundary portion BP between the bending region BA and the display region DA provided on the rear surface 130a of the flexible substrate 130 and the other end IPb provided adjacent to the boundary portion BP on the rear surface 130a of the flexible substrate 130. In this case, based on the appropriate etching condition and the glass etching process, the inclined surface IP of the opening portion OP according to the second embodiment can be formed not to include Figure 5A the tail portion TP shown. Thus, the inclined surface IP of the opening portion OP according to the second embodiment can be formed to form an acute angle (i.e., the inclination is 15 degrees to 17 degrees) with the rear surface 130a of the flexible substrate 130. Thus, the flexible display panel 100 can be more suitable for an inner bending structure.

[0112] For example, when the bending region BA of the flexible display panel 100 is bent in the inner bending structure, the inclined surface IP of the opening portion OP according to the second embodiment may not be surrounded by the bending region BA. Thus, due to the bending region BA bent in the inner bending structure, a relatively low bending stress (or low pressure) can be applied to the inclined surface IP of the opening portion OP. On the other hand, when the bending region BA of the flexible display panel 100 is bent in the outer bending structure, the inclined surface IP of the opening portion OP according to the second embodiment may be surrounded by the bending region BA. Thus, due to the bending region BA bent in the outer bending structure, a relatively high bending stress (or high pressure) can be applied to the inclined surface IP of the opening portion OP. Therefore, when the bending region BA is bent in the inner bending structure, a relatively low bending stress can be applied to one end IPa adjacent to the bending region BA and having a relatively thin thickness of the inclined surface IP of the opening portion OP. Thus, the flexible display panel 100 may not break or be damaged. However, when the bending region BA is bent in the outer bending structure, a relatively high bending stress can be applied to one end IPa. Thus, the flexible display panel 100 may break or be damaged. Therefore, the opening portion OP according to the second embodiment can be applied to the flexible display panel 100 folded or bent in the inner bending structure.

[0113] Referring to Figure 5C , the opening portion OP according to the third embodiment of the present disclosure can be formed by a glass etching process based on an over-etching condition. Here, the over-etching condition can be defined as a glass etching process that performs etching for a time exceeding a predetermined reference etching time to etch the glass by a certain thickness.

[0114] The mask pattern MP can be formed on the rear surface 110a of the glass substrate 110 that overlaps with a plurality of display regions DA1 and DA2 except for the bending region BA. Then, the opening portion OP according to the third embodiment can be formed by etching the region of the convex cross-sectional shape of the glass substrate 110 that overlaps with the bending region BA using the mask pattern MP as a mask based on the over-etching situation through a glass etching process.

[0115] The opening portion OP according to the third embodiment may include an inclined surface IP having a concave bending shape or a shape inclined at a specific angle. In this case, the cross-sectional area of the opening portion OP parallel to the rear surface 130a of the flexible substrate 130 may decrease in a direction away from the rear surface 130a of the flexible substrate 130. The third angle “θ3” between the inclined surface IP of the opening portion OP and the rear surface 130a of the flexible substrate 130 may be an obtuse angle and, as an example, may be 105 degrees to 145 degrees. Therefore, the opening portion OP according to the third embodiment may include an undercut UC between the rear surface 130a of the flexible substrate 130 and the inclined surface IP. Here, the etching process time may be longer than the reference etching time, and the portion of the glass substrate 110 that contacts the boundary portion BP between the bending region BA and the display region DA may be over-etched to form the undercut UC.

[0116] The inclined surface IP of the opening portion OP according to the third embodiment can be formed by a glass etching process based on the over-etching situation, and thus, may include a concave bending shape or a shape inclined in a direction opposite to the middle portion of the opening portion OP between one end IPa provided on the rear surface 130a of the flexible substrate 130 and overlapping the boundary portion BP between the bending region BA and the display region DA and the other end IPb provided in the bending region BA on the rear surface 130a of the glass substrate 110. Therefore, the inclined surface IP of the opening portion OP according to the third embodiment can be formed to form an obtuse angle (i.e., an inclination of 105 degrees to 145 degrees) with the rear surface 130a of the flexible substrate 130. Thus, the flexible display panel 100 can be applied to all inner bending structures and outer bending structures, but is more suitable for outer bending structures.

[0117] For example, when the bending region BA of the flexible display panel 100 is bent in an inner bending structure, the inclined surface IP of the opening portion OP according to the third embodiment may not be surrounded by the bending region BA. Therefore, due to the bending region BA bent in the inner bending structure, a relatively low bending stress (or low pressure) can be applied to the inclined surface IP of the opening portion OP. Therefore, the opening portion OP according to the third embodiment can be applied to the flexible display panel 100 that is folded or bent in an inner bending structure.

[0118] In addition, when the bending region BA of the flexible display panel 100 is bent in the outer bending structure, the inclined surface IP of the opening portion OP according to the third embodiment can be surrounded by the bending region BA. Therefore, the inclined surface IP of the opening portion OP can guide the outer bending of the bending region BA, or can be inclined or can have a concave shape. Thus, even when the bending region BA is bent in the outer bending structure, the inclined surface IP of the opening portion OP can be inclined or can have a concave shape. Therefore, even when the bending region BA is bent in the outer bending structure, a relatively low bending stress can be applied thereto, whereby the flexible display panel 100 can be not broken or damaged. Accordingly, the opening portion OP according to the third embodiment can be applied to the flexible display panel 100 that is folded or bent in the outer bending structure, and in particular, the opening portion OP can guide the outer bending of the bending region BA, and thus can be applied to the flexible display panel 100 that is bent in the outer bending structure rather than the inner bending structure.

[0119] Figure 6 is a diagram for describing the bending stress of the bending region and the filler of the flexible display device 10 according to an embodiment of the present disclosure.

[0120] Refer to Figure 6 , in the flexible display device 10 according to an embodiment of the present disclosure, the thickness of the filler 190 filled in the opening portion OP of the glass substrate 110 can be set such that when the display panel 100 is bent, the neutral plane NP is located in the display unit 150 in the bending region BA.

[0121] Specifically, when the bending region BA of the flexible display panel 100 is bent along the inner bending structure (or the outer bending structure) with a predetermined radius of curvature, a compressive stress (or tensile stress) CS and a tensile stress TS can be applied to the flexible display panel 100 based on the mechanical and physical property values (e.g., elastic modulus, thickness, curvature, and Poisson's ratio) of the flexible substrate 130, the display unit 150, the cover film 170, and the filler 190. In this case, the bending region BA of the flexible display panel 100 can include a neutral plane NP where the compressive stress CS and the tensile stress TS are zero (0). Therefore, as the distance from the neutral plane NP increases, a relatively high compressive stress CS and a tensile stress TS can be applied thereto. Accordingly, the thickness of the filler 190 can be set within a range where the pixel circuit layer of the display unit 150 is disposed in the neutral plane NP. Thus, the pixel circuit layer of the display unit 150 can be located in the neutral plane NP. Therefore, even when the filler 190 and the bending region BA of the flexible display panel 100 are bent with a certain radius of curvature, a zero (0) bending stress can be applied thereto. Thus, the pixel circuit layer can be not damaged by the bending stress and can be bent.

[0122] Figure 7A , Figure 7B and Figure 7C are diagrams for describing various structures of a filler for a flexible display device according to embodiments of the present disclosure.

[0123] Referring to Figure 6 and Figure 7A , the filler 190 according to the first embodiment can be filled into the opening portion to have a concave cross-sectional shape. In this case, the filler 190 can have the thinnest thickness in the middle portion of the bending region BA. That is, the rear surface 190a of the filler 190 can have a concave bending shape between the rear surface 110a of the glass substrate 110 and the middle portion of the bending region BA. Therefore, the filler 190 can have a thickness that gradually thins in the direction from the rear surface 110a of the glass substrate 110 to the middle portion of the bending region BA.

[0124] Referring to Figure 6 and Figure 7B , the filler 190 according to the second embodiment can be filled into the opening portion to include a recessed groove portion 190b provided in a concave shape. In this case, the groove portion 190b of the filler 190 can be provided on the middle portion of the bending region BA. That is, the groove portion 190b of the filler 190 can include an inclined portion that inclines from the rear surface 110a of the glass substrate 110 toward the middle portion of the bending region BA. Therefore, the filler 190 can have a thickness that gradually thins in the direction from the rear surface 110a of the glass substrate 110 to the middle portion of the bending region BA. For example, the groove portion 190b of the filler 190 can include a Y-shaped or W-shaped cross-sectional surface.

[0125] The filler 190 according to the first embodiment and the second embodiment can have a thickness that gradually thins in the direction closer to the middle portion of the bending region BA. Therefore, the bending region BA can be easily bent. In particular, when the bending region BA of the flexible display panel 100 is bent in an outer bending structure, agglomeration occurring in the middle portion of the bending region BA can be minimized, and damage to the bending region BA caused by agglomeration can be prevented.

[0126] Referring to Figure 6 and Figure 7C, the filler 190 according to the third embodiment can be completely filled into the opening portion to have a convex cross-sectional shape. In this case, the filler 190 can have the thickest thickness in the middle portion of the bending region BA. That is, the rear surface 190c of the filler 190 can have a convex bending shape between the rear surface 110a of the glass substrate 110 and the middle portion of the bending region BA. Therefore, the filler 190 can have a thickness that gradually thickens in the direction from the rear surface 110a of the glass substrate 110 to the middle portion of the bending region BA.

[0127] The filler 190 according to the third embodiment can more stably support the bending region BA of the flexible display panel 100 and can absorb (or buffer) the impact applied to the bending region BA of the flexible display panel 100, thereby improving the reliability and durability of the bending region BA of the flexible display panel 100.

[0128] Figure 8 is a cross-sectional view for describing a flexible display device 30 according to another embodiment of the present disclosure, and shows an example in which two or more opening portions are provided in the glass substrate of the flexible display panel in the flexible display device according to the embodiment of the present disclosure shown. Therefore, hereinafter, only the opening portions and the elements related to the opening portions will be described, and the repeated description of other elements will be omitted. Figures 1 to 7C Referring to

[0129] Referring to Figure 8 , the flexible display device 30 according to another embodiment of the present disclosure can be applied to a rollable display device, and can include a plurality of display regions DA and a bending region BA between two adjacent display regions of the plurality of display regions DA. In this case, the width of each of the plurality of display regions DA and the width of the bending region BA can be set based on the radius of curvature at which the flexible display panel 100 is wound in a spiral shape.

[0130] In the flexible display device 30 according to another embodiment of the present disclosure, the glass substrate 110 can include a plurality of opening portions OP that respectively overlap with the plurality of bending regions BA.

[0131] The plurality of opening portions OP can be provided on the glass substrate 110 at a certain interval D. Each of the plurality of opening portions OP can include an inclined surface having a bending shape. The opening portions OP are as described above, and therefore, their repeated description is omitted.

[0132] The glass substrate 110 according to the present embodiment can include a plurality of support members that are parallel to each other and have an opening portion OP therebetween.

[0133] According to an embodiment, a plurality of support members can support the flexible substrate 130 overlapping each of the plurality of display regions DA in a planar state. In this case, the flexible substrate 130 can be wound in a spiral shape according to the bending of each of the plurality of bending regions BA, and in this case, each of the plurality of display regions DA can maintain a planar state.

[0134] According to another embodiment, a plurality of support members can support the flexible substrate 130 overlapping each of the plurality of display regions DA, and can be bent together with the bending of the flexible substrate 130. In this case, the flexible substrate 130 can be wound in a spiral shape according to the bending of each of the plurality of display regions DA and the bending of each of the plurality of bending regions BA. To this end, the plurality of support members (i.e., the glass substrate 110) can be etched through a glass etching process to have a thickness such that each support member can be bent together with the bending of the flexible substrate 130. For example, the glass substrate 110 can prevent water or oxygen from penetrating into the flexible substrate 130 and can be etched to have a thickness of 0.01 mm to 1.0 mm, which enables the glass substrate 110 to be bent together with the flexible substrate 130.

[0135] According to another embodiment, the flexible display device 30 may further include a filler 190 filled (or buried) into the plurality of opening portions OP. The filler 190 is as described above, and thus, its repeated description is omitted.

[0136] As Figure 9A shown, the flexible display device 30 according to another embodiment of the present disclosure can be wound in a spiral shape along an inner winding structure based on the inner bending structure of the flexible display panel 100, or as Figure 9B shown, can be wound in a spiral shape along an outer winding structure based on the outer bending structure of the flexible display panel 100.

[0137] Figure 10A 、 Figure 10B 、 Figure 10C and Figure 10D are micrographs showing the shape of the opening portion based on the glass etching condition in the flexible display device according to an embodiment of the present disclosure. Figure 10A shows the shape of the opening portion based on the soft etching condition, Figure 10B shows the shape of the opening portion based on the appropriate etching condition, Figure 10C shows the shape of the opening portion based on the over-etching condition according to the first embodiment, and Figure 10D shows the shape of the opening portion based on the over-etching condition according to the second embodiment.

[0138] As Figure 10AAs shown, as a result of forming the opening portion OP by performing a glass etching process based on the soft etching condition on the glass substrate 110, it can be checked that the angle between the inclined surface IP of the opening portion OP and the rear surface of the flexible substrate 130 is measured to be 13 degrees, and the inclined surface IP of the opening portion OP is formed to include a tail portion TP based on the soft etching condition.

[0139] As Figure 10B shown, as a result of forming the opening portion OP by performing a glass etching process based on the appropriate etching condition on the glass substrate 110, it can be checked that the angle between the inclined surface IP of the opening portion OP and the rear surface of the flexible substrate 130 is measured to be 46 degrees, and the inclined surface IP of the opening portion OP is formed to have a concave curved shape without a tail portion TP based on the appropriate etching condition.

[0140] As Figure 10C shown, as a result of forming the opening portion OP by performing a glass etching process based on the over-etching condition on the glass substrate 110 according to the first embodiment, it can be checked that the angle between the inclined surface IP of the opening portion OP and the rear surface of the flexible substrate 130 is measured to be 107 degrees, and the inclined surface IP of the opening portion OP is formed to have a concave curved shape or a shape including an undercut UC and inclined at a certain angle without a tail portion TP based on the over-etching condition.

[0141] As Figure 10D shown, as a result of forming the opening portion OP by performing a glass etching process based on the over-etching condition having a longer time than the over-etching condition according to the first embodiment according to the second embodiment on the glass substrate 110, it can be checked that the angle between the inclined surface IP of the opening portion OP and the rear surface of the flexible substrate 130 is measured to be 126 degrees and the inclined surface IP of the opening portion OP is formed to have a convex curved shape or a concave curved shape including a deeper undercut UC and inclined at a certain angle without a tail portion TP based on the over-etching condition.

[0142] Thus, in the flexible display device according to an embodiment of the present disclosure, the opening portion OP may be formed by etching the glass substrate 110 overlapping the bending region of the flexible display panel based on the inner bending structure or the outer bending structure of the flexible display panel and based on over-etching or appropriate etching conditions. As a result, even without the laser release process, the flexible display device according to an embodiment of the present disclosure can be manufactured, and thus, the reliability for preventing water or oxygen from infiltrating and the bending reliability can be enhanced. In addition, according to the present disclosure, the laser release process of separating the entire glass substrate 110 from the flexible substrate 130, the rear protective film attached to the rear surface of the flexible substrate 130, and the attachment process performed on the rear protective film can be omitted, thereby improving productivity.

[0143] Figure 11 is a perspective view of a flexible display device 40 according to another embodiment of the present disclosure, and Figure 12 is a cross-sectional view taken along line II-II' shown in Figure 11 FIG. Figure 11 and Figure 12 show an example of additionally providing an etch stop pattern in the flexible display device shown in Figures 1 to 7C FIG. Hereinafter, in elements other than the etch stop pattern and elements related to the etch stop pattern, the same reference numerals denote the same elements, and thus, their repeated description is omitted.

[0144] Referring to Figure 11 and Figure 12 FIG. 4 and FIG. 5, the flexible display device 40 according to another embodiment of the present disclosure may further include an etch stop pattern ESP (or an etch barrier pattern or an etch barrier layer) provided between the glass substrate 110 and the flexible substrate 130 overlapping the bending region BA of the flexible display panel 100.

[0145] The etch stop pattern ESP may be provided between the glass substrate 110 and the flexible substrate 130 to overlap the opening portion OP of the glass substrate 110. For example, the etch stop pattern ESP may have a size wider than the opening portion OP of the glass substrate 110, or may have a size wider than the bending region BA of the flexible display panel 100.

[0146] The etch stop pattern ESP according to an embodiment may prevent the flexible substrate 130 from being damaged by an etchant of a glass etching process for forming the opening portion OP in the glass substrate 110. The etch stop pattern ESP may be formed of a material having corrosion resistance (or tolerance) to the etchant for the glass etching process.

[0147] According to an embodiment, the etch stop pattern ESP may include one material among Cr, CrOx, Pt, TiO2, and Ni. In this case, the etch stop pattern ESP may be formed on the front surface of the glass substrate 110 through a sputtering process, and then, may be formed on the front surface of the glass substrate 110 through a patterning process into a pattern type overlapping with the bending region BA of the flexible display panel 100. Alternatively, the etch stop pattern ESP may be formed on the front surface of the glass substrate 110 through a patterning process using a pattern mask into a pattern type overlapping with the bending region BA of the flexible display panel 100, and in this case, the patterning process may be omitted. The etch stop pattern ESP may be covered by the flexible substrate 130. Alternatively, according to an embodiment, the etch stop pattern ESP may be disposed between the glass substrate 110 and the flexible substrate 130 so as to be coupled to the entire rear surface of the flexible substrate 130, and in this case, the etch stop pattern ESP may be formed on the front surface of the glass substrate 110 through a sputtering process and then may be covered by the flexible substrate 130.

[0148] According to another embodiment, the etch stop pattern ESP may include one material among polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polypropylene (PP), and polycarbonate (PC), and for example, may include polyethylene terephthalate (PET). In this case, according to another embodiment, the etch stop pattern ESP may be attached to the front surface of the glass substrate 110 in a pattern type overlapping with the bending region BA of the flexible display panel 100 and then may be covered by the flexible substrate 130.

[0149] According to another embodiment of the present disclosure, the flexible display device 40 may include an etch stop pattern ESP disposed between the glass substrate 110 overlapping with the bending region BA of the flexible display panel 100 and the flexible substrate 130, and thus, the flexible substrate 130 may be prevented from being damaged by a glass etching process for forming an opening part OP in the glass substrate 110.

[0150] The etch stop pattern ESP of the flexible display device 40 according to another embodiment of the present disclosure may be similarly applied to Figure 8 the flexible display device 30 shown. In this case, Figure 8 the flexible display device 30 shown may further include a plurality of etch stop patterns disposed between the glass substrate 110 and the flexible substrate 130 to overlap with each of the plurality of bending regions BA or to overlap with each of the plurality of opening parts OP provided in the glass substrate 110.

[0151] Figure 13 is a perspective view showing a flexible display device 50 according to another embodiment of the present invention,Figure 14 is a cross-sectional view taken along line III-III' shown in Figure 11 and is a plan view showing the pattern frame shown in Figure 15 shows Figure 13 the pattern frame shown in Figures 13 to 15 shows an example of additionally providing a pattern frame in the flexible display device shown in Figures 1 to 9B In the following, in elements other than the pattern frame and elements related to the pattern frame, the same reference numerals denote the same elements, and thus, their repeated descriptions are omitted.

[0152] Referring to Figures 13 to 14 , a flexible display device 50 according to another embodiment of the present disclosure may further include a pattern frame 140 that covers the rear surface of the flexible display panel 100.

[0153] The pattern frame 140 may be coupled to the rear surface of the glass substrate 110 and the filler 190 to cover the rear surface of the flexible display panel 100, and thus, may support the rear surface of the flexible display panel 100, increase the stiffness of the flexible display panel 100 against external physical impacts, and increase the flatness of the flexible display panel 100. In particular, the pattern frame 140 may support or cover the rear surface of the filler 190 filled in the opening portion OP of the glass substrate 110, and thus, may prevent the bending region BA of the flexible display panel 100 from having undulations caused by the step height between the filler 190 and the glass substrate 110.

[0154] The pattern frame 140 according to an embodiment may be coupled to the rear surfaces of the glass substrate 110 and the filler 190 through a frame bonding member. In this case, the frame bonding member may be an optically clear adhesive (OCA), an optically clear resin (OCR), or a pressure-sensitive adhesive (PSA).

[0155] The pattern frame 140 according to an embodiment may include a thin metal plate containing a metal material. According to another embodiment, as shown in Figure 15 , the pattern frame 140 may include a perforated plate or a mesh plate containing a plurality of opening patterns 141 having a polygonal shape. For example, the pattern frame 140 may include one material among aluminum (Al), magnesium (Mg), an Al alloy, an Mg alloy, and an Mg-Li alloy.

[0156] A flexible display device 50 according to another embodiment of the present disclosure may have the same effects as the flexible display device shown in Figures 1 to 9B and may include a pattern frame 140 provided on the rear surface of the flexible display panel 100, thereby increasing the stiffness and flatness of the flexible display panel 100.

[0157] The pattern frame 140 of the flexible display device 50 according to another embodiment of the present disclosure can be similarly applied to Figure 8 , Figure 11 and Figure 12 the flexible display devices 30 and 40 shown in

[0158] Figure 16 FIG. 10 is a perspective view showing a flexible display device 60 according to another embodiment of the present disclosure, Figure 17 and FIG. 11 is a cross-sectional view taken along the line IV-IV' shown in Figure 16 FIG. 10. Figure 16 And Figure 17 FIGS. 12 and 13 show examples of additionally providing a coating in the flexible display device shown in Figures 1 to 9B FIG. 10. Hereinafter, in elements other than the coating and elements related to the coating, the same reference numerals denote the same elements, and thus, their repeated description is omitted.

[0159] Referring to Figure 16 and Figure 17 FIGS. 12 and 13, the flexible display device 60 according to another embodiment of the present disclosure may further include a coating 195 covering the rear surface of the flexible display panel 100.

[0160] The coating 195 may be coated on the rear surfaces of the glass substrate 110 and the filler 190 to cover the rear surface of the flexible display panel 100. Thus, the rear surface of the flexible display panel 100 can be protected from external impact and the flatness of the flexible display panel 100 can be increased. In particular, the coating 195 may support or cover the rear surface of the filler 190 filled into the opening portion OP of the glass substrate 110. Thus, the bending region BA of the flexible display panel 100 can be prevented from having undulations caused by the filler 190.

[0161] A liquid resin (e.g., an organic resin) may be coated on the rear surface of the filler 190 and the rear surface of the glass substrate 110 through a spraying process or a dispensing process, and then, the liquid resin may be cured through a photocuring process. The coating 195 according to an embodiment may be formed to cover the entire rear surface of the flexible display panel 100.

[0162] The coating 195 according to an embodiment may be formed of the same material as the filler 190. In this case, the filler 190 may be formed of a coating material that is filled (or buried) into the opening portion OP of the glass substrate 110 and cured during the formation of the coating 195. Thus, the process of forming the filler 190 in the opening portion OP of the glass substrate 110 can be omitted.

[0163] The flexible display device 60 according to another embodiment of the present disclosure may have the same as Figures 1 to 9BThe same effect as that of the flexible display device shown, and may include a coating 195 covering the entire rear surface of the flexible display panel 100, thereby increasing the stiffness and flatness of the flexible display panel 100.

[0164] The coating 195 of the flexible display device 60 according to another embodiment of the present disclosure can be similarly applied to Figure 8 , Figure 11 and Figure 12 the flexible display devices 30 and 40 shown.

[0165] Figure 18 is a perspective view of a flexible display device 70 according to another embodiment of the present disclosure, Figure 19 is a cross-sectional view taken along the line V-V' shown in Figure 18 . Figure 18 and Figure 19 show examples of additionally providing an etching sacrificial layer in the flexible display devices shown in Figure 1 to 9. Hereinafter, in elements other than the etching sacrificial layer and elements related to the etching sacrificial layer, the same reference numerals denote the same elements, and thus, their repeated descriptions are omitted.

[0166] Referring to Figure 18 and Figure 19 , the flexible display device 70 according to another embodiment of the present disclosure may further include an etching sacrificial layer 120 disposed between the glass substrate 110 and the flexible substrate 130.

[0167] The etching sacrificial layer 120 may be disposed between the glass substrate 110 and the flexible substrate 130, and the etching sacrificial layer does not overlap with the opening portion OP of the glass substrate 110. That is, the etching sacrificial layer 120 may be formed on the entire front surface of the glass substrate 110 and may be disposed in the entire space between the glass substrate 110 and the flexible substrate 130. However, the region of the etching sacrificial layer 120 overlapping with the opening portion OP of the glass substrate 110 can be removed by etching through a glass etching process for forming the opening portion OP of the glass substrate 110. Therefore, other regions except the region overlapping with the opening portion OP of the glass substrate 110 can be disposed between the glass substrate 110 and the flexible substrate 130.

[0168] In the glass etching process for forming the opening portion OP of the glass substrate 110, the etching sacrificial layer 120 can be rapidly etched by the etchant. Thus, the etched surface of the opening portion OP of the glass can be set to an inverted conical structure. In other words, after etching the opening portion OP of the glass substrate 110 in the glass etching process, the etching sacrificial layer 120 can be exposed to the etchant and can be etched more than the glass substrate 110. Thus, an undercut can be rapidly formed between the front surface of the glass substrate 110 and the rear surface of the flexible substrate 130. Therefore, the etching sacrificial layer 120 can shorten the processing time spent in the glass etching process based on the over-etching condition of the etched glass surface for forming the inverted conical structure of the opening portion OP. Therefore, the etching sacrificial layer 120 can allow the front surface of the glass substrate 110 connected to the rear surface of the flexible substrate 130 to be etched faster than the side surface of the glass substrate 110 in the glass etching process and thus can be referred to as an etching acceleration layer.

[0169] For example, after the etching sacrificial layer 120 is exposed to the etchant, the etching sacrificial layer 120 can be etched faster between the front surface of the glass substrate 110 and the rear surface of the flexible substrate 130 than the glass substrate 110. Thus, the etchant can be allowed to rapidly penetrate into the space between the front surface of the glass substrate 110 and the rear surface of the flexible substrate 130. When the etchant penetrates into the space between the front surface of the glass substrate 110 and the rear surface of the flexible substrate 130, the over-etching rate corresponding to the etched surface of the boundary portion BP between the bending region BA and the display region DA shown in Figure 5C can increase, and thus, an undercut UC can be rapidly formed between the rear surface 130a of the flexible substrate 130 and the inclined surface IP.

[0170] The penetration amount of the etchant in the region where the etching sacrificial layer 120 is etched can increase as the thickness of the etching sacrificial layer 120 becomes thicker. Thus, as the thickness of the etching sacrificial layer 120 becomes thicker, the undercut UC of the glass etched surface can be formed faster. Therefore, the thickness of the etching sacrificial layer 120 can be set based on the thickness of the glass substrate 110 and the glass etching process time. For example, the etching sacrificial layer 120 can have a thickness of 0.2 μm or more, but is not limited thereto.

[0171] The etching sacrificial layer 120 according to the embodiment can be formed of a material that is easily etched by the etchant applied to the glass etching process. For example, the etching sacrificial layer 120 can include an inorganic material such as silicon oxide (SiOx) or silicon nitride (SiNx), and as an example, can include SiOx having a thickness of 0.2 μm or more.

[0172] The etch sacrificial layer 120 and the glass substrate 110 exposed at the opening portion OP formed by the glass etching process in the glass substrate 110 may be covered with a filler 190 filled into the opening portion OP. That is, the filler 190 may be filled up to the undercut UC of the opening portion OP, and may cover the etch sacrificial layer 120 exposed at the opening portion OP of the glass substrate 110 and the etched surfaces of each of the glass substrate 110.

[0173] A flexible display device 70 according to another embodiment of the present disclosure may have the same effects as the flexible display device shown in Figures 1 to 9B and may include an etch sacrificial layer 120 disposed between the glass substrate 110 and the flexible substrate 130. Accordingly, the glass etched surface of the opening portion OP provided in the glass substrate 110 may have an inverted conical structure, and the processing time of the glass etching process based on the over-etching process for forming the opening portion OP may be reduced.

[0174] Optionally, the flexible display device 70 according to another embodiment of the present disclosure may further include an etch stop layer (or etch barrier layer) disposed between the flexible substrate 130 and the etch sacrificial layer 120.

[0175] The etch stop layer may prevent the flexible substrate 130 from being damaged by the etchant of the glass etching process for forming the opening portion OP in the glass substrate 110. That is, when the etchant etches the etch sacrificial layer 120, a part of the flexible substrate 130 overlapping with the opening portion OP may be exposed to the etchant and damaged by the etchant. Accordingly, the etch stop layer may be disposed between the flexible substrate 130 and the etch sacrificial layer 120 to overlap with the opening portion OP, and may prevent the rear surface of the flexible substrate 130 from being exposed to the etchant.

[0176] Unlike the etch sacrificial layer 120, the etch stop layer according to an embodiment may be formed of a material having corrosion resistance (or tolerance) to the etchant used in the glass etching process. For example, when the glass etching process uses an etchant including an HF-based material, the etch stop layer may include one material among Cr, CrOx, Pt, TiO2, and Ni.

[0177] The etch stop layer may be formed to cover the entire rear surface of the flexible substrate 130, or may be formed in a pattern type having a size wider than the opening portion OP of the glass substrate 110.

[0178] The etch sacrificial layer 120 of the flexible display device 70 according to another embodiment of the present disclosure may be similarly applied to Figure 8 , Figure 11 and Figure 12 and Figures 14 to 17The flexible display devices 30, 40, 50, and 60 shown in

[0179] Figure 20 is a micrograph showing the shape of the opening portion based on the over-etching condition in the flexible display panel according to an experimental example of the present disclosure in a glass etching process.

[0180] As Figure 20 shown, as a result of performing a glass etching process to form the opening portion OP based on the over-etching condition on the glass substrate 110, it can be checked that the angle between the inclined surface IP of the opening portion OP and the rear surface of the flexible substrate 130 is measured to be 164 degrees (or -16 degrees), and based on the over-etching condition and the etched sacrificial layer 120, the glass etching surface of the opening portion OP has an inverted conical structure including a large and deep undercut UC. In particular, it can be checked that the undercut UC of the opening portion OP having the etched sacrificial layer 120 applied thereto is larger and deeper than Figure 10C and Figure 10D the undercut UC of the opening portion OP shown in

[0181] The flexible display device according to the present disclosure can be applied to a single-fold display device, a multi-fold display device, a single-bend display device, a multi-bend display device, or a rollable display device that includes at least one bending region and folds or bends according to the bending of the bending region.

[0182] The flexible display device according to the present disclosure will be described below.

[0183] The flexible display device according to an embodiment of the present disclosure may include: a flexible substrate including a plurality of display regions and a bending region between the plurality of display regions; a display unit disposed in the plurality of display regions and the bending region of the flexible substrate; a cover film covering the display unit; and a support member including a plurality of support parts respectively supporting the plurality of display regions and an elastic part supporting the bending part, wherein the plurality of support parts and the elastic part may include different materials, and the boundary surface between each of the plurality of support parts and the elastic part may have a concave curved shape or a shape inclined at a specific angle.

[0184] According to an embodiment of the present disclosure, each of the plurality of support parts may include a glass material, and the elastic part may include an adhesive material.

[0185] According to one embodiment of the present disclosure, each of the plurality of support members may be directly connected to the rear surface of the flexible substrate.

[0186] According to one embodiment of the present disclosure, the elastic portion may have a concave cross-sectional shape or a convex cross-sectional shape.

[0187] According to one embodiment of the present disclosure, the elastic portion may further include a groove portion, and a middle portion of the groove portion may overlap with a middle portion of the bending region.

[0188] According to one embodiment of the present disclosure, the flexible substrate may be folded in a direction in which the plurality of support members face each other.

[0189] A flexible display device according to one embodiment of the present disclosure may include: a flexible substrate, which may include a plurality of display regions and a bending region between the plurality of display regions; a display unit, which may be disposed in the plurality of display regions and the bending region of the flexible substrate; a cover film, which covers the display unit; and a glass substrate, which may include an opening portion disposed on the rear surface of the flexible substrate to overlap with the bending region, wherein the opening portion may include an inclined surface having a bent shape.

[0190] According to one embodiment of the present disclosure, the glass substrate may include a plurality of support members that support the rear surface of the flexible substrate, the plurality of support members overlap with each of the plurality of display regions, and each of the plurality of support members includes an inclined surface facing the opening portion, and the opening portion may be disposed between the plurality of support members.

[0191] According to one embodiment of the present disclosure, the inclined surface may have a concave bent shape.

[0192] According to one embodiment of the present disclosure, a cross-sectional area of the opening portion parallel to the rear surface of the flexible substrate increases in a direction away from the rear surface of the flexible substrate.

[0193] According to one embodiment of the present disclosure, an angle between the rear surface of the flexible substrate and the boundary surface may be an acute angle.

[0194] According to one embodiment of the present disclosure, an angle between the rear surface of the flexible substrate and the boundary surface may be in a range of 15 degrees to 70 degrees.

[0195] According to one embodiment of the present disclosure, the opening portion may include an undercut between the rear surface of the flexible substrate and the boundary surface.

[0196] According to one embodiment of the present disclosure, an angle between the rear surface of the flexible substrate and the boundary surface may be an obtuse angle.

[0197] According to one embodiment of the present disclosure, the flexible display device may further include a filler filled in the opening portion.

[0198] According to one embodiment of the present disclosure, the filler may have a concave cross-sectional shape or a convex cross-sectional shape.

[0199] According to one embodiment of the present disclosure, the filler may further include a groove portion, and a middle portion of the groove portion may overlap with a middle portion of the bending region.

[0200] According to one embodiment of the present disclosure, the flexible substrate may be folded in a direction in which a plurality of display regions face each other.

[0201] According to one embodiment of the present disclosure, the flexible display device may further include an etch stop pattern disposed between the filler and the flexible substrate.

[0202] According to one embodiment of the present disclosure, the flexible display device may further include a coating covering a rear surface of the glass substrate and a rear surface of the filler.

[0203] According to one embodiment of the present disclosure, the coating may include the same material as the material of the filler.

[0204] According to one embodiment of the present disclosure, the flexible display device may further include a pattern frame coupled to a rear surface of the glass substrate and a rear surface of the filler.

[0205] According to one embodiment of the present disclosure, the pattern frame may include a perforated plate or a mesh plate including a plurality of opening portions.

[0206] According to one embodiment of the present disclosure, the flexible display device may further include an etch sacrificial layer disposed between the flexible substrate and a region of the glass substrate other than a region of the glass substrate overlapping with the opening portion.

[0207] According to one embodiment of the present disclosure, the etch sacrificial layer may include silicon oxide SiOx or silicon nitride SiNx.

[0208] According to one embodiment of the present disclosure, the opening portion may include an undercut between a rear surface of the flexible substrate and a boundary surface.

[0209] According to one embodiment of the present disclosure, the flexible display device may further include a filler filled in the opening portion, wherein the filler may cover an etched surface of the etch sacrificial layer and the glass substrate exposed at the opening portion.

[0210] According to an embodiment of the present disclosure, the flexible display device may further include an etch stop layer disposed between the flexible substrate and the etched sacrificial layer to overlap with an opening portion of the glass substrate.

[0211] According to an embodiment of the present disclosure, the glass substrate may have a thickness of 0.01 mm to 1.0 mm.

[0212] According to an embodiment of the present disclosure, the flexible substrate may be wound in a spiral shape.

[0213] The above-described features, structures, and effects of the present disclosure are included in at least one embodiment of the present disclosure, but are not limited to one embodiment. In addition, the features, structures, and effects described in at least one embodiment of the present disclosure may be achieved by those skilled in the art through combinations or modifications of other embodiments. Therefore, the content associated with the combinations and modifications should be construed as being within the scope of the present disclosure.

[0214] It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is intended to cover modifications and variations of the present disclosure as long as they fall within the scope of the appended claims and their equivalents.

[0215] Cross-reference to related applications

[0216] This application claims the benefit and priority of Korean Patent Application No. 10-2018-0075161, filed on June 29, 2018, and Korean Patent Application No. 10-2018-0169924, filed on December 26, 2018, each of which is incorporated herein by reference in its entirety as if fully set forth herein.

Claims

1. A flexible display device, the flexible display device comprising: A flexible substrate, the flexible substrate comprising a plurality of display regions and a bending region; A display unit, the display unit being disposed in the plurality of display regions and the bending region of the flexible substrate; A cover film, the cover film covering the display unit; A glass substrate, the glass substrate comprising an opening portion disposed on a rear surface of the flexible substrate to overlap with the bending region; A filler, the filler being filled in the opening portion; And An etch stop pattern, the etch stop pattern being disposed between the filler and the flexible substrate, and Wherein the etch stop pattern has a dimension wider than that of the opening portion.

2. The flexible display device according to claim 1, Among them, The glass substrate comprises: A portion in direct contact with the rear surface of the flexible substrate without an intermediate layer, and Another portion in contact with the etch stop pattern, and Wherein the filler is in direct contact with the etch stop pattern.

3. The flexible display device according to claim 1, wherein, The etch stop pattern has a dimension wider than that of the bending region.

4. The flexible display device according to claim 1, wherein, The etch stop pattern comprises one material selected from Cr, CrOx, Pt, TiO2, and Ni.

5. The flexible display device according to claim 1, wherein, The etch stop pattern is attached to the glass substrate overlapping with the bending region and comprises one material selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polypropylene (PP), and polycarbonate (PC).

6. The flexible display device according to claim 1, wherein The opening portion comprises an inclined surface having a curved shape.

7. The flexible display device according to claim 6, wherein, The glass substrate further comprises a plurality of support members, the support members supporting the rear surface of the flexible substrate overlapping with each of the plurality of display regions, and each of the support members comprises an inclined surface facing the opening portion, and The opening portion is disposed between the plurality of support members.

8. A flexible display device, the flexible display device comprising: A flexible substrate, the flexible substrate comprising a plurality of display regions and a bending region; A display unit, the display unit being disposed in the plurality of display regions and the bending region of the flexible substrate; A cover film, the cover film covering the display unit; And A glass substrate, the glass substrate comprising an opening portion disposed on a rear surface of the flexible substrate to overlap with the bending region, Wherein the opening portion comprises: An inclined surface having a curved shape, and An undercut between the rear surface of the flexible substrate and the inclined surface.

9. The flexible display device according to claim 8, wherein, The undercut comprises a portion of the glass substrate in contact with a boundary portion between the bending region and the display region.

10. The flexible display device according to claim 8, wherein, An angle between the rear surface of the flexible substrate and the inclined surface is an obtuse angle.

11. The flexible display device according to claim 8, wherein, The glass substrate further comprises a plurality of support members, the support members supporting the rear surface of the flexible substrate overlapping with each of the plurality of display regions, and each of the support members comprises an inclined surface facing the opening portion, and The opening portion is provided between the plurality of support members.

12. The flexible display device according to claim 8, wherein, The cross-sectional area of the opening portion parallel to the rear surface of the flexible substrate decreases in a direction away from the rear surface of the flexible substrate.

13. The flexible display device according to claim 8, further comprising a filler filled in the opening portion.

14. The flexible display device according to any one of claims 1 to 7 and 13, further comprising a coating covering the rear surface of the glass substrate and the rear surface of the filler.

15. The flexible display device according to claim 14, wherein, The coating includes the same material as the material of the filler.

16. The flexible display device according to any one of claims 1 to 7 and 13, further comprising a pattern frame coupled to the rear surface of the glass substrate and the rear surface of the filler.

17. The flexible display device according to claim 16, wherein, The pattern frame includes a perforated plate or a mesh plate, and the perforated plate or the mesh plate includes a plurality of openings.

18. The flexible display device according to claim 8, further comprising an etching sacrificial layer provided between the flexible substrate and the glass substrate in a region other than a region overlapping with the opening portion of the glass substrate.

19. The flexible display device according to claim 18, wherein, The etching sacrificial layer includes silicon oxide SiOx or silicon nitride SiNx.

20. The flexible display device according to claim 18, further comprising a filler filled in the opening portion, Among them, The filler covers the etched surface of the etching sacrificial layer and the glass substrate exposed at the opening portion.

21. The flexible display device according to any one of claims 18 to 20, further comprising an etching stop layer provided between the flexible substrate and the etching sacrificial layer to overlap with the opening portion of the glass substrate.

22. The flexible display device according to any one of claims 1 to 7, 13, and 20, wherein, The filler has a concave or convex cross-sectional shape.

23. The flexible display device according to claim 22, wherein, The filler further includes a groove portion, and A central portion of the groove portion overlaps with a central portion of the bending region.

24. The flexible display device according to any one of claims 1 to 13 and 18 to 20, wherein, The thickness of the glass substrate is 0.01 mm to 1.0 mm.

25. The flexible display device according to any one of claims 1 to 13 and 18 to 20, wherein, The flexible substrate is wound in a spiral shape.

26. The flexible display device according to any one of claims 1 to 13 and 18 to 20, wherein, The flexible substrate is folded in a direction in which the plurality of display regions face each other.

27. The flexible display device according to any one of claims 1 to 13 and 18 to 20, wherein Two or more opening portions are provided in the glass substrate.

28. The flexible display device according to claim 27, wherein, The bending region overlaps with each of the two or more opening portions.

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