Flexible substrate, display device using the same, and method of manufacturing the same

Abstract

A flexible substrate, a display device using the same, and a method of manufacturing the same, which are capable of preventing surface damage to the flexible substrate during a process of separating a carrier substrate from the flexible substrate, for manufacturing a flexible display device and achieving an improvement in yield. The flexible substrate includes: a first substrate layer made of a conductive material and having a plurality of first opening portions; a second substrate layer disposed on the first substrate layer and having a plurality of contact holes; a third substrate layer disposed on the second substrate layer and electrically connected to the first substrate layer through the plurality of contact holes, the third substrate layer being made of a conductive material and having a plurality of second opening portions; and a fourth substrate layer disposed on the third substrate layer.

Description

[0001] This application claims the benefit of Korean Patent Application No. 10-2024-0163456, filed on November 15, 2024, which is incorporated herein by reference as if fully set forth herein. Technical Field

[0002] This disclosure relates to display devices, and more particularly, to flexible substrates, display devices using said flexible substrates, and methods for manufacturing the same, which can prevent surface damage to the flexible substrate during processes that separate a carrier substrate from the flexible substrate, for manufacturing flexible display devices and achieving improved yield. Background Technology

[0003] Image display devices that present various information on a screen are a core technology of the information and communication era, and are developing towards thinner, lighter, more portable, and higher-performance devices. Therefore, display devices that can be manufactured with a light and thin structure are attracting attention.

[0004] Specific examples of such display devices include liquid crystal display (LCD) devices, quantum dot (QD) display devices, field emission display (FED) devices, and organic light emitting diode (OLED) display devices.

[0005] OLED display devices include light-emitting diodes (LEDs) as their basic constituent elements, which comprise cathodes and anodes facing each other with an organic light-emitting layer (OLED) inserted therebetween. When holes and electrons injected into the OLED from the cathode and anode, respectively, recombine with each other within the OLED, light is emitted, thus displaying an image.

[0006] Therefore, OLED displays are self-emissive display devices, and thus, they are advantageous not only in terms of power consumption due to low voltage driving, but also in terms of excellent color rendering, fast response time, wide viewing angle, and high contrast ratio (CR). In this regard, OLED displays are attracting attention as the next generation of display devices, and are being researched.

[0007] Meanwhile, in recent years, there has been an increased demand for flexible display devices using flexible substrates such as plastic substrates. Such flexible display devices have the advantages of large-screen display and portability, as they are portable in a folded state and display images in an unfolded state.

[0008] Because of the flexible nature of such plastic substrates, it is difficult to use the plastic substrate itself in the manufacturing process of display devices. For this reason, the process is performed by attaching the plastic substrate to one surface of a carrier substrate, such as a glass substrate. After this process is completed, the carrier substrate is separated from the plastic substrate, and thus, the display device is manufactured.

[0009] The carrier substrate is separated from the plastic substrate by laser irradiation. However, this process may damage the surface of the plastic substrate.

[0010] Furthermore, laser irradiation may be uneven or the energy may be locally concentrated. Therefore, impacts may occur during substrate separation, potentially damaging the components. This results in a decrease in yield. Summary of the Invention

[0011] Therefore, this disclosure relates to a flexible substrate that substantially eliminates one or more problems caused by the limitations and disadvantages of related technologies, a display device using the flexible substrate, and a method of manufacturing the same.

[0012] One object of this disclosure is to provide a display device and a method thereof for manufacturing a flexible display device, which can prevent damage to the surface of the flexible substrate during the process of separating the carrier substrate from the flexible substrate.

[0013] Another object of this disclosure is to provide a display device and a method for manufacturing the same, which can prevent surface damage to the flexible substrate during the process of separating the carrier substrate from the flexible substrate, thereby improving the yield.

[0014] The purpose of this disclosure is not limited to the foregoing, and other purposes of this disclosure, which have not yet been described, will become more apparent to those skilled in the art from the following detailed description.

[0015] According to one aspect of this disclosure, a flexible substrate includes: a first substrate layer made of a conductive material and having a plurality of first opening portions; a second substrate layer disposed on the first substrate layer and having a plurality of contact holes; a third substrate layer disposed on the second substrate layer and electrically connected to the first substrate layer through a plurality of contact holes, the third substrate layer being made of a conductive material and having a plurality of second opening portions; and a fourth substrate layer disposed on the third substrate layer.

[0016] According to another aspect of this disclosure, the display device includes a flexible substrate according to one embodiment of this disclosure, a thin-film transistor on the flexible substrate, an organic light-emitting diode connected to the thin-film transistor, and an encapsulation film disposed on the organic light-emitting diode.

[0017] According to another aspect of this disclosure, a method of manufacturing a display device includes: forming a separation layer on a carrier substrate; forming a first substrate layer on the separation layer, which is made of a conductive material and has a plurality of first opening portions; forming a second substrate layer on the first substrate layer, which has a plurality of contact holes; forming a third substrate layer on the second substrate layer, which is electrically connected to the first substrate layer through the plurality of contact holes and is made of a conductive material, the third substrate layer having a plurality of second opening portions; forming a fourth substrate layer on the third substrate layer; sequentially forming a pixel layer having thin-film transistors and light-emitting diodes and an encapsulation film on the fourth substrate layer; and separating the carrier substrate by applying a voltage or current to the third substrate layer to generate heat in the first substrate layer.

[0018] Further details of other implementation schemes are included in the following detailed description and figures.

[0019] According to this disclosure, the carrier substrate is separated from the flexible substrate under conditions where heat is generated in the first substrate layer. Therefore, the flexible substrate is free of foreign matter or scratches from the carrier substrate.

[0020] Since the carrier substrate is separated from the flexible substrate under the condition of heat generation in the first substrate layer, damage to the surface of the flexible substrate can be prevented, and damage to the components caused by the impact generated during the separation of the carrier substrate from the flexible substrate can be prevented.

[0021] In addition, the first substrate layer and the third substrate layer can be used as heat sinks for the display device.

[0022] The effects of the embodiments according to this disclosure are not limited to those described above, and may include more effects. Attached Figure Description

[0023] The accompanying drawings are included to provide a further understanding of this disclosure and are incorporated in and constitute a part of this application. The drawings illustrate embodiments of the disclosure and, together with the description, serve to illustrate the principles of the disclosure. In the drawings:

[0024] Figure 1 This is a schematic cross-sectional view of a flexible display device according to one embodiment of the present disclosure;

[0025] Figure 2 This is a schematic cross-sectional view showing an example of a display panel of a flexible display device according to this embodiment of the present disclosure;

[0026] Figure 3 This is a cross-sectional view showing a flexible substrate according to one embodiment of the present disclosure;

[0027] Figure 4A This is a plan view of the second transparent electrode layer according to the first embodiment of this disclosure, and Figure 4BThis is a plan view of the first transparent electrode layer according to the first embodiment of this disclosure;

[0028] Figure 5A This is a plan view of the second transparent electrode layer according to the second embodiment of this disclosure, and Figure 5B This is a plan view of the first transparent electrode layer according to the second embodiment of this disclosure;

[0029] Figure 6A This is a plan view of the second transparent electrode layer according to the third embodiment of this disclosure, and Figure 6B This is a plan view of the first transparent electrode layer according to the third embodiment of this disclosure;

[0030] Figure 7A This is a plan view of the second transparent electrode layer according to the fourth embodiment of this disclosure, and Figure 7B This is a plan view of the first transparent electrode layer according to the fourth embodiment of this disclosure;

[0031] Figure 8A This is a plan view of the second transparent electrode layer according to the fifth embodiment of this disclosure, and Figure 8B This is a plan view of the first transparent electrode layer according to the fifth embodiment of this disclosure;

[0032] Figure 9A This is a plan view of the second transparent electrode layer according to the sixth embodiment of this disclosure, and Figure 9B This is a plan view of the first transparent electrode layer according to the sixth embodiment of this disclosure;

[0033] Figure 10A This is a plan view of the second transparent electrode layer according to the seventh embodiment of this disclosure, and Figure 10B This is a plan view of the first transparent electrode layer according to the seventh embodiment of this disclosure; and

[0034] Figure 11 This is a cross-sectional view illustrating a method of manufacturing a display device according to one embodiment of the present disclosure. Detailed Implementation

[0035] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Throughout this disclosure, the same reference numerals denote the same constituent elements.

[0036] In the following description of this disclosure, detailed descriptions of known techniques or configurations incorporated herein will be omitted where such descriptions might obscure the subject matter of this disclosure. Furthermore, the terms used below relating to the constituent elements have been chosen for ease of preparation of this disclosure and may differ in practice from the names of the corresponding elements.

[0037] The shapes, dimensions, ratios, angles, quantities, etc., shown in the accompanying drawings to illustrate embodiments of this disclosure are for illustrative purposes only and are not limited to the content of the drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts.

[0038] In the following description, detailed descriptions of known techniques related to this disclosure may be omitted to avoid unnecessarily obscuring the subject matter of this disclosure.

[0039] When terms such as “including,” “having,” and “contains” are used throughout the specification, additional components may exist unless “only” is used. Unless otherwise specified, components described in the singular form encompass components described in the plural form.

[0040] It should be understood that the components included in the embodiments of this disclosure include error ranges, although they are not described in detail elsewhere.

[0041] In describing various embodiments of this disclosure, when using positional relation terms such as “on,” “above,” “below,” and “next to,” at least one insert element may exist between two elements unless “closely” or “directly” is used.

[0042] When describing various embodiments of this disclosure, when describing temporal relationships, for example, when using terms such as "after", "following", "next" and "before", there may be cases where events are discontinuous unless "immediately" or "directly" is used.

[0043] Furthermore, while terms including ordinal numbers such as "first" or "second" may be used to describe individual constituent elements, the constituent elements are not limited to these terms, and these terms are used only for the purpose of distinguishing one constituent element from other constituent elements. Therefore, within the scope of this disclosure, unless otherwise specifically stated, a first constituent element may refer to a second constituent element.

[0044] The corresponding features of the various embodiments of this disclosure may be combined or integrated in whole or in part, and may be technically variably related or operable, and these embodiments may be implemented independently or in combination.

[0045] In the following description, a display device according to one embodiment of the present disclosure will be described with reference to the accompanying drawings.

[0046] Figure 1 This is a schematic cross-sectional view of a flexible display device according to one embodiment of the present disclosure. Figure 2This is a schematic cross-sectional view illustrating an example of a display panel of a flexible display device according to an embodiment of the present disclosure.

[0047] like Figure 1 and Figure 2 As shown, the display device according to this embodiment of the present disclosure may include a display panel 110, a back plate 120 disposed below the display panel 110, and a cover window 130 disposed above the display panel 110.

[0048] The cover window 130 can be made of impact-resistant and light-transmitting reinforced glass or plastic film to protect the display panel 110 from external impacts, moisture, heat, etc. The cover window 130 can be formed with a thickness of 30μm to 200μm to meet strength and folding characteristics.

[0049] When the cover window 130 is made of a plastic film, the plastic film may include, but is not limited to, polyimide (PI) film, polyethylene terephthalate (PET) film, polypropylene glycol (PPG) film, polycarbonate (PC) film, etc.

[0050] When the cover window 130 is made of tempered glass, it may break due to external forces or stress. In this case, to prevent fragments of the cover window 130 from scattering, an anti-scattering film can be attached to the upper surface of the cover window 130. The anti-scattering film may include, for example, a base film comprising polyethylene terephthalate (PET), colorless polyimide (CPI), a laminate of polyethylene terephthalate (PET) and colorless polyimide (CPI), etc. A hard coating, an anti-reflective layer, an anti-fingerprint layer, etc., may be coated on the upper surface of the base film.

[0051] The display panel 110 may include an active area in which multiple pixels are set to display an image, and a non-active area disposed around the active area to surround the active area. The non-active area may include pad portions coupled to an external drive module.

[0052] The display panel 110 can be a flexible display panel including multiple pixels formed on a flexible substrate. The display panel 110 can be an organic light-emitting diode panel.

[0053] The backsheet 120 may be made of a polymer film. The polymer film that can be used for the backsheet 120 may be made of polyimide (PI), polyethylene terephthalate (PET), polycarbonate (PC) or polyethylene naphthalate (PEN), but is not limited to these.

[0054] like Figure 2As shown, the display panel 110 according to this embodiment of the present disclosure may include a flexible substrate 140, a thin film transistor Tr disposed on the flexible substrate 140, a light-emitting diode D disposed above the flexible substrate 140 and connected to the thin film transistor Tr, and an encapsulation film 180 configured to cover the light-emitting diode D.

[0055] The flexible substrate 140 has a multilayer structure. This will be described in detail later.

[0056] Multiple buffer layers 151 can be formed on the flexible substrate 140. The multiple buffer layers 151 can be constructed by stacking inorganic insulating materials such as silicon oxide or silicon nitride to form a multilayer structure. The multiple buffer layers 151 can be omitted.

[0057] A thin-film transistor Tr can be formed on the multi-buffer layer 151. For example, a semiconductor layer 152 can be formed on the multi-buffer layer 151. The semiconductor layer 152 can be made of an oxide semiconductor material or polysilicon. When the semiconductor layer 152 is made of an oxide semiconductor material, a light-shielding pattern (not shown) can be formed below the semiconductor layer 152. The light-shielding pattern prevents light from incident on the semiconductor layer 152, thereby preventing the semiconductor layer 152 from deteriorating due to light. On the other hand, the semiconductor layer 152 can be made of polysilicon. In this case, the opposite edges of the semiconductor layer 152 may be doped with impurities.

[0058] A gate insulating layer 153 made of an insulating material is formed on the semiconductor layer 152. The gate insulating layer 153 may be made of an inorganic insulating material such as silicon oxide or silicon nitride.

[0059] A gate electrode 155 made of a conductive material, such as metal, is formed on the gate insulating layer 153, such that the gate electrode 155 corresponds to the center portion of the semiconductor layer 152.

[0060] Although the gate insulating layer 153 is in Figure 2 The diagram shows the layer formed over the entire surface of the flexible substrate 140, but this disclosure is not limited thereto. The gate insulating layer 153 may be patterned to have the same shape as the gate electrode 155.

[0061] An interlayer insulating layer 157 made of an insulating material is formed on the gate electrode 155. The interlayer insulating layer 157 may be formed of an inorganic insulating material (e.g., silicon oxide or silicon nitride) or an organic insulating material (e.g., benzocyclobutene or photoreactive acrylic). The interlayer insulating layer 157 has a first contact hole 154 and a second contact hole 156 configured to expose opposite sides of the semiconductor layer 152. The first contact hole 154 and the second contact hole 156 are disposed on opposite sides of the gate electrode 155 and spaced apart from the gate electrode 155.

[0062] In this case, the first contact hole 154 and the second contact hole 156 are also formed in the gate insulating layer 153. Unlike the above case, when the gate insulating layer 153 is patterned to have the same shape as the gate electrode 155, the first contact hole 154 and the second contact hole 156 can be formed only in the interlayer insulating layer 157.

[0063] A source electrode 160 and a drain electrode 162 made of a conductive material, such as a metal, are formed on the interlayer insulating layer 157. The source electrode 160 and the drain electrode 162 are spaced apart from each other relative to the gate electrode 155, and contact opposite sides of the semiconductor layer 152 through a first contact hole 154 and a second contact hole 156, respectively.

[0064] The aforementioned semiconductor layer 152, gate electrode 155, source electrode 160, and drain electrode 162 constitute a thin-film transistor Tr. The thin-film transistor Tr can be a drive transistor configured to control the current flowing through the light-emitting diode D.

[0065] Although thin-film transistors Tr in Figure 2 The diagram shows a coplanar structure in which gate electrode 155, source electrode 160, and drain electrode 162 are disposed above semiconductor layer 152, but this disclosure is not limited thereto. The thin-film transistor Tr may have an anti-interleaved structure in which the gate electrode is disposed below the semiconductor layer and the source and drain electrodes are disposed above the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

[0066] Although not shown, gate lines and data lines define a pixel area through their intersection, and also form switching elements connected to the gate lines and data lines. These switching elements are connected to a thin-film transistor Tr (driving transistor).

[0067] Furthermore, the power lines are formed to extend parallel to the gate lines or data lines while being spaced apart from them. A storage capacitor may also be configured to constantly maintain the voltage of the gate electrode of the thin-film transistor Tr for one frame.

[0068] A protective layer 164 is formed to cover the thin-film transistor Tr, the protective layer 164 having a drain contact hole 166 configured to expose the drain electrode 162 of the thin-film transistor Tr.

[0069] A first electrode 170 is formed in the protective layer 164, which is connected to the drain electrode 162 of the thin-film transistor Tr through a drain contact hole 166, such that the first electrode 170 is separated from the first electrodes 170 of other pixel areas. The first electrode 170 can be an anode and can be made of a conductive material with a relatively large work function. For example, the first electrode 170 can be made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

[0070] Furthermore, when the display panel 110 according to this embodiment of the present disclosure is a top-emitting organic light-emitting diode panel, a reflective electrode or reflective layer may also be formed below the first electrode 170. For example, the reflective electrode or reflective layer may be made of an aluminum-palladium-copper (APC) alloy.

[0071] Furthermore, a dam layer 176 is formed on the protective layer 164, configured to cover the edge of the first electrode 170. The dam layer 176 exposes the central portion of the first electrode 170 (corresponding to the pixel region).

[0072] An organic light-emitting layer 172 is formed on the first electrode 170. The organic light-emitting layer 172 can be a light-emitting material layer made of a light-emitting material and having a single-layer structure. In contrast, the organic light-emitting layer 172 can have a multilayer structure in which a hole injection layer, a hole transport layer, a light-emitting material layer, an electron transport layer and an electron injection layer are sequentially stacked on the first electrode 170 to improve luminous efficiency.

[0073] A second electrode 174 is formed above the flexible substrate 140 on which the organic light-emitting layer 172 is formed. The second electrode 174 is disposed over the entire active region and is made of a conductive material with a relatively small work function, and therefore can be used as a cathode. For example, the second electrode 174 can be made of aluminum (Al), magnesium (Mg), silver (Ag) or alloys thereof.

[0074] The first electrode 170, the organic light-emitting layer 172, and the second electrode 174 constitute a light-emitting diode D.

[0075] An encapsulation film 180 is formed on the second electrode 174 to prevent ambient moisture from penetrating the light-emitting diode D. The encapsulation film 180 may have a stacked structure of a first inorganic insulating layer 182, an organic insulating layer 184, and a second inorganic insulating layer 186, but is not limited thereto.

[0076] In addition, a polarizing plate (not shown) configured to reduce the reflection of external light can be attached to the encapsulation film 180. For example, the polarizing plate can be a circular polarizing plate.

[0077] Figure 3 This is a cross-sectional view showing the flexible substrate 140 according to this embodiment of the present disclosure.

[0078] like Figure 3 As shown, the flexible substrate 140 of the display panel 110 according to this embodiment of the present disclosure may include a lower layer 141, an intermediate layer 142, and an upper layer 143. The flexible substrate 140 may have a stacked structure in which the intermediate layer 142 is located between the lower layer 141 and the upper layer 143.

[0079] The lower layer 141 and the upper layer 143 may be made of plastic materials. For example, the lower layer 141 and the upper layer 143 may be made of polymer materials (such as polyimide, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyethersulfone, polyarylate, polysulfone, cyclic olefin copolymers, etc.).

[0080] The intermediate layer 142 can be made of, for example, inorganic materials such as silicon oxide (SiO2). x ), silicon nitride (SiN) x ) or silicon nitride oxide (SiO) x N y It consists of a single-layer structure or a stacked structure.

[0081] A first transparent electrode layer 144 is disposed on the back surface of the lower layer 141. A second transparent electrode layer 145 is disposed between the intermediate layer 142 and the upper layer 143. A plurality of contact holes are formed in the lower layer 141 and the intermediate layer 142. The first transparent electrode layer 144 and the second transparent electrode layer 145 are electrically connected to each other through connecting electrodes 146 filling the respective contact holes. The connecting electrodes 146 may be formed of the same material as the first transparent electrode layer 144 or the second transparent electrode layer 145. For ease of manufacturing, it is preferable that the connecting electrodes 146 are formed of the same material as the second transparent electrode layer 145.

[0082] The first transparent electrode layer 144 and the second transparent electrode layer 145 can each be configured with various patterns.

[0083] In some exemplary embodiments, the first transparent electrode layer 144 can serve as the first substrate layer, the lower layer 141 and the middle layer 142 can serve as the second substrate layer, the second transparent electrode layer 145 can serve as the third substrate layer, and the upper layer 143 can serve as the fourth substrate layer.

[0084] Figure 4A This is a plan view of the second transparent electrode layer according to the first embodiment of this disclosure. Figure 4B This is a plan view of the first transparent electrode layer according to the first embodiment of this disclosure.

[0085] like Figure 4A As shown, a second transparent electrode layer (represented by reference numeral "145") according to a first embodiment of the present disclosure is disposed between the intermediate layer 142 and the upper layer 143 of the flexible substrate 140. The second transparent electrode layer 145 may include a plurality of second opening portions 145a. The plurality of second opening portions 145a have uniform dimensions and are disposed at a uniform density.

[0086] like Figure 4BAs shown, a first transparent electrode layer (denoted by reference numeral "144") according to a first embodiment of the present disclosure is disposed on the back surface of the lower layer 141 of the flexible substrate 140. The first transparent electrode layer 144 includes a plurality of first opening portions 144a. The plurality of first opening portions 144a also have uniform dimensions and are disposed at a uniform density.

[0087] like Figure 4A and Figure 4B As shown, the first transparent electrode layer 144 and the second transparent electrode layer 145 are electrically connected to each other through a plurality of contact holes 145b. The plurality of contact holes 145b are also arranged at a uniform density. (See reference...) Figure 3 The first transparent electrode layer 144 and the second transparent electrode layer 145 are electrically connected to each other through connecting electrodes 146 that respectively fill a plurality of contact holes 145b.

[0088] like Figure 4A and Figure 4B As shown, the size of each first opening portion 144a is smaller than the size of each second opening portion 145a. Furthermore, the number of first opening portions 144a is greater than the number of second opening portions 145a, and the density of the first opening portions 144a is higher than the density of the second opening portions 145a.

[0089] Furthermore, the linewidth d1 between the first openings 144a of the first transparent electrode layer 144 is narrower than the linewidth d2 between the second openings 145a of the second transparent electrode layer 145. Therefore, the resistance of the first transparent electrode layer 144 is greater than the resistance of the second transparent electrode layer 145.

[0090] Therefore, when a voltage (current) is applied to the second transparent electrode layer 145, the first transparent electrode layer 144 can generate heat.

[0091] Since the resistance values ​​of the first transparent electrode layer 144 and the second transparent electrode layer 145 can vary depending on the direction of voltage (current) application, the first transparent electrode layer 144 and the second transparent electrode layer 145 can be configured with various patterns to compensate for resistance variations.

[0092] Figure 5A This is a plan view of the second transparent electrode layer according to the second embodiment of this disclosure. Figure 5B This is a plan view of the first transparent electrode layer according to the second embodiment of this disclosure. Figure 5A and Figure 5B An embodiment in which a voltage (current) is applied to one side A of the second transparent electrode layer is shown.

[0093] like Figure 5AAs shown, a second transparent electrode layer (represented by reference numeral "245") according to a second embodiment of the present disclosure is disposed between the intermediate layer 142 and the upper layer 143 of the flexible substrate 140. The second transparent electrode layer 245 may include a plurality of second opening portions 245a. The plurality of second opening portions 245a have uniform dimensions and are arranged at a uniform density.

[0094] like Figure 5B As shown, according to a second embodiment of the present disclosure, a first transparent electrode layer (denoted by reference numeral "244") is disposed on the back surface of the lower layer 141 of the flexible substrate 140. The first transparent electrode layer 244 includes a plurality of first opening portions 244a. The plurality of first opening portions 244a may have different sizes depending on their positions and may be arranged at different densities depending on their positions.

[0095] like Figure 5A and Figure 5B As shown, the first transparent electrode layer 244 and the second transparent electrode layer 245 are electrically connected to each other through a plurality of contact holes 245b. The plurality of contact holes 245b are also arranged at a uniform density. (See reference...) Figure 3 The first transparent electrode layer 244 and the second transparent electrode layer 245 are electrically connected to each other through connecting electrodes 146 that respectively fill multiple contact holes 245b.

[0096] Configuration and reference of the second transparent electrode layer 245 according to the second embodiment of this disclosure Figure 4A The configuration of the second transparent electrode layer 145 is described in the same manner. Of course, it is assumed that a voltage (current) is applied to one side A of the second transparent electrode layer 245.

[0097] like Figure 5A and Figure 5B As shown, the size of each first opening portion 244a is smaller than the size of each second opening portion 245a. Furthermore, the number of first opening portions 244a is greater than the number of second opening portions 245a, and the density of the first opening portions 244a is higher than the density of the second opening portions 245a.

[0098] Furthermore, the linewidth d1 between the first openings 244a of the first transparent electrode layer 244 is narrower than the linewidth d2 between the second openings 245a of the second transparent electrode layer 245. Therefore, the resistance of the first transparent electrode layer 244 is greater than the resistance of the second transparent electrode layer 245.

[0099] Therefore, when a voltage (current) is applied to the second transparent electrode layer 245, the first transparent electrode layer 244 can generate heat.

[0100] Furthermore, the dimensions of the plurality of first opening portions 244a of the first transparent electrode layer 244 and the linewidth between the first opening portions 244a of the first transparent electrode layer 244 can vary according to the direction of voltage (current) application.

[0101] For example, assuming a voltage (current) is applied to one side A of the second transparent electrode layer 245, the size of the first opening portion 244a of the first transparent electrode layer 244 gradually decreases as the first transparent electrode layer 244 extends from the region corresponding to the side A where the voltage (current) is applied in the opposite direction to the voltage (current) application region, and the density of the first opening portions 244a of the first transparent electrode layer 244 gradually increases as the first transparent electrode layer 244 extends from the voltage (current) application region in the opposite direction to the voltage (current) application region. Therefore, the linewidth between the first opening portions 244a of the first transparent electrode layer 244 gradually decreases as the first transparent electrode layer 244 extends from the voltage (current) application region in the opposite direction to the voltage (current) application region. For example, assuming the linewidth between the first opening portions 244a of the first transparent electrode layer 244 is “d1” in the voltage (current) application region and “d3” in the region away from the voltage (current) application region, d1 is greater than d3.

[0102] Therefore, even when the resistance of the second transparent electrode layer 245 changes in the direction of voltage (current) application, the first transparent electrode layer 244 can generate heat uniformly throughout its entire region because the linewidth of the first transparent electrode layer 244 changes according to the direction of voltage (current) application.

[0103] Figure 6A This is a plan view of the second transparent electrode layer according to the third embodiment of this disclosure. Figure 6B This is a plan view of the first transparent electrode layer according to the third embodiment of this disclosure. Figure 6A and Figure 6B An embodiment in which a voltage (current) is applied to one side A of the second transparent electrode layer is shown.

[0104] like Figure 6A As shown, a second transparent electrode layer (denoted by reference numeral "345") according to a third embodiment of the present disclosure is disposed between the intermediate layer 142 and the upper layer 143 of the flexible substrate 140. The second transparent electrode layer 345 may include a plurality of second opening portions 345a. The plurality of second opening portions 345a have uniform dimensions and are disposed at a uniform density.

[0105] like Figure 6BAs shown, a first transparent electrode layer (denoted by reference numeral "344") according to a third embodiment of the present disclosure is disposed on the back surface of the lower layer 141 of the flexible substrate 140. The first transparent electrode layer 344 includes a plurality of first opening portions 344a. The plurality of first opening portions 344a have uniform dimensions and are disposed at a uniform density.

[0106] like Figure 6A and Figure 6B As shown, the first transparent electrode layer 344 and the second transparent electrode layer 345 are electrically connected to each other through a plurality of contact holes 345b. The plurality of contact holes 345b are arranged at different densities according to the voltage (current) application direction. (See reference...) Figure 3 The first transparent electrode layer 344 and the second transparent electrode layer 345 are electrically connected to each other through connecting electrodes 146 that respectively fill multiple contact holes 345b.

[0107] The configuration and reference of the second transparent electrode layer 345 according to the third embodiment of this disclosure Figure 4A The configuration of the second transparent electrode layer 145 is described in the same manner. Of course, it is assumed that a voltage (current) is applied to one side A of the second transparent electrode layer 345.

[0108] like Figure 6A and Figure 6B As shown, the size of each first opening portion 344a is smaller than the size of each second opening portion 345a. Furthermore, the number of first opening portions 344a is greater than the number of second opening portions 345a, and the density of the first opening portions 344a is higher than the density of the second opening portions 345a.

[0109] Furthermore, the linewidth d1 between the first openings 344a of the first transparent electrode layer 344 is narrower than the linewidth d2 between the second openings 345a of the second transparent electrode layer 345. Therefore, the resistance of the first transparent electrode layer 344 is greater than the resistance of the second transparent electrode layer 345.

[0110] Therefore, when a voltage (current) is applied to the second transparent electrode layer 345, the first transparent electrode layer 344 can generate heat.

[0111] Furthermore, the density of multiple contact holes 345b can vary depending on the direction of voltage (current) application.

[0112] For example, when assuming that a voltage (current) is applied to one side A of the second transparent electrode layer 345, the density of the plurality of contact holes 345b can gradually increase as the second transparent electrode layer 345 extends from the side A to which the voltage (current) is applied in the opposite direction to side A of the second transparent electrode layer 345.

[0113] Therefore, even when the resistance of the second transparent electrode layer 345 changes in the direction of voltage (current) application, the first transparent electrode layer 344 can still generate heat uniformly throughout its entire area because the density of the multiple contact holes 345b changes according to the direction of voltage (current) application.

[0114] Figure 7A This is a plan view of the second transparent electrode layer according to the fourth embodiment of this disclosure. Figure 7B This is a plan view of the first transparent electrode layer according to the fourth embodiment of this disclosure. Figure 7A and Figure 7B An embodiment in which voltage (current) is applied to the right side A, left side B, upper side C, and lower side D of the second transparent electrode layer is shown.

[0115] like Figure 7A As shown, a second transparent electrode layer (denoted by reference numeral "445") according to a fourth embodiment of the present disclosure is disposed between the intermediate layer 142 and the upper layer 143 of the flexible substrate 140. The second transparent electrode layer 445 may include a plurality of second opening portions 445a and a plurality of contact holes 445b. The plurality of second opening portions 445a have uniform dimensions and are arranged at a uniform density.

[0116] like Figure 7B As shown, a first transparent electrode layer (denoted by reference numeral "444") according to a fourth embodiment of the present disclosure is disposed on the back surface of the lower layer 141 of the flexible substrate 140. The first transparent electrode layer 444 includes a plurality of first opening portions 444a. The plurality of first opening portions 444a have uniform dimensions and are disposed at a uniform density.

[0117] like Figure 7A and Figure 7B As shown, the first transparent electrode layer 444 and the second transparent electrode layer 445 are electrically connected to each other through a plurality of contact holes 445b. The plurality of contact holes 445b are arranged with different densities depending on the direction of voltage (current) application. For example, the density of the plurality of contact holes 445b can gradually increase as the second transparent electrode layer 445 extends from its left side A, right side B, upper side C, and lower side D towards its center where a voltage (current) is applied. (See reference...) Figure 3 The first transparent electrode layer 444 and the second transparent electrode layer 445 are electrically connected to each other through connecting electrodes 146 that respectively fill multiple contact holes 445b.

[0118] like Figure 7A and Figure 7BAs shown, the size of each first opening portion 444a is smaller than the size of each second opening portion 445a. Furthermore, the number of first opening portions 444a is greater than the number of second opening portions 445a, and the density of the first opening portions 444a is higher than the density of the second opening portions 445a.

[0119] Furthermore, the linewidth d1 between the first openings 444a of the first transparent electrode layer 444 is narrower than the linewidth d2 between the second openings 445a of the second transparent electrode layer 445. Therefore, the resistance of the first transparent electrode layer 444 is greater than the resistance of the second transparent electrode layer 445.

[0120] Therefore, when a voltage (current) is applied to the second transparent electrode layer 445, the first transparent electrode layer 444 can generate heat.

[0121] Because a voltage (current) is applied to the left side A, right side B, upper side C, and lower side D of the second transparent electrode layer 445, the voltage (current) gradually decreases as the second transparent electrode layer 445 extends towards its center due to the surface resistance of the second transparent electrode layer 445. However, because the density of the plurality of contact holes 445b gradually increases as the second transparent electrode layer 445 extends from its left side A, right side B, upper side C, and lower side D towards its center, the first transparent electrode layer 444 can generate heat uniformly throughout its entire region.

[0122] Figure 8A This is a plan view of the second transparent electrode layer according to the fifth embodiment of this disclosure. Figure 8B This is a plan view of the first transparent electrode layer according to the fifth embodiment of this disclosure. Figure 8A and Figure 8B An embodiment in which voltage (current) is applied to the left side A, right side B, upper side C, and lower side D of the second transparent electrode layer is shown.

[0123] like Figure 8A As shown, a second transparent electrode layer (denoted by reference numeral "545") according to a fifth embodiment of the present disclosure is disposed between the intermediate layer 142 and the upper layer 143 of the flexible substrate 140. The second transparent electrode layer 545 includes a plurality of second opening portions 545a. The plurality of second opening portions 545a have uniform dimensions and are arranged at a uniform density.

[0124] like Figure 8B As shown, a first transparent electrode layer (denoted by reference numeral "544") according to a fifth embodiment of the present disclosure is disposed on the back surface of the lower layer 141 of the flexible substrate 140. The first transparent electrode layer 544 includes a plurality of first opening portions 544a. The plurality of first opening portions 544a may have different sizes depending on their positions and may be arranged at different densities depending on their positions.

[0125] like Figure 8A and Figure 8B As shown, the first transparent electrode layer 544 and the second transparent electrode layer 545 are electrically connected to each other through a plurality of contact holes 545b. The plurality of contact holes 545b are also arranged at a uniform density. (See reference...) Figure 3 The first transparent electrode layer 544 and the second transparent electrode layer 545 can be electrically connected to each other through the connecting electrodes 146 that respectively fill multiple contact holes 545b.

[0126] like Figure 8A and Figure 8B As shown, the size of each first opening portion 544a is smaller than the size of each second opening portion 545a. Furthermore, the number of first opening portions 544a is greater than the number of second opening portions 545a, and the density of the first opening portions 544a is higher than the density of the second opening portions 545a.

[0127] Furthermore, the linewidth d1 between the first openings 544a of the first transparent electrode layer 544 is narrower than the linewidth d2 between the second openings 545a of the second transparent electrode layer 545. Therefore, the resistance of the first transparent electrode layer 544 is greater than the resistance of the second transparent electrode layer 545.

[0128] Therefore, when a voltage (current) is applied to the second transparent electrode layer 545, the first transparent electrode layer 544 can generate heat.

[0129] Furthermore, the dimensions of the plurality of first opening portions 544a of the first transparent electrode layer 544 and the linewidth between the first opening portions 544a of the first transparent electrode layer 544 can vary according to the direction of voltage (current) application.

[0130] For example, assuming a voltage (current) is applied to the left side A, right side B, upper side C, and lower side D of the second transparent electrode layer 545, the size of the first opening portion 544a of the first transparent electrode layer 544 gradually decreases as the first transparent electrode layer 544 extends from the regions corresponding to the applied voltage (current) on the left side A, right side B, upper side C, and lower side D towards its central region, and the density of the first opening portions 544a of the first transparent electrode layer 544 gradually increases as the first transparent electrode layer 544 extends from the regions corresponding to the applied voltage (current) on the left side A, right side B, upper side C, and lower side D towards its central region. Therefore, the linewidth between the first opening portions 544a of the first transparent electrode layer 544 gradually decreases as the first transparent electrode layer 544 extends from the regions corresponding to the applied voltage (current) on the left side A, right side B, upper side C, and lower side D towards its central region. For example, when it is assumed that the linewidth between the first opening portions 544a of the first transparent electrode layer 544 in the regions corresponding to the left side A, right side B, upper side C and lower side D where the applied voltage (current) is applied is “d1”, and the linewidth between the first opening portions 544a of the first transparent electrode layer 544 in the central region is “d3”, d1 is greater than d3.

[0131] Therefore, even when the resistance of the second transparent electrode layer 545 changes in the direction of voltage (current) application, the first transparent electrode layer 544 can generate heat uniformly because the linewidth of the first transparent electrode layer 544 changes according to the direction of voltage (current) application.

[0132] Figure 9A This is a plan view of the second transparent electrode layer according to the sixth embodiment of this disclosure. Figure 9B This is a plan view of the first transparent electrode layer according to the sixth embodiment of this disclosure. Figure 9A and Figure 9B An embodiment in which voltage (current) is applied to the left side A, right side B, upper side C, and lower side D of the second transparent electrode layer is shown.

[0133] like Figure 9A As shown, a second transparent electrode layer (denoted by reference numeral "645") according to a sixth embodiment of the present disclosure is disposed between the intermediate layer 142 and the upper layer 143 of the flexible substrate 140. The second transparent electrode layer 645 includes a plurality of second opening portions 645a. The plurality of second opening portions 645a may have uniform size and may be arranged at a uniform density.

[0134] like Figure 9BAs shown, a first transparent electrode layer (denoted by reference numeral "644") according to a sixth embodiment of the present disclosure is disposed on the back surface of the lower layer 141 of the flexible substrate 140. The first transparent electrode layer 644 includes a plurality of first opening portions 644a. Each of the plurality of first opening portions 644a has a quadrilateral ring shape. The plurality of first opening portions 644a have different sizes, and the smaller first opening portions are sequentially disposed within the outermost first opening portion having the largest size, such that the smaller first opening portions are disposed within the larger first opening portions.

[0135] like Figure 9A and Figure 9B As shown, the first transparent electrode layer 644 and the second transparent electrode layer 645 are electrically connected to each other through a plurality of contact holes 645b. The plurality of contact holes 645b are arranged with different densities depending on the direction of voltage (current) application. For example, the density of the plurality of contact holes 645b can gradually increase as the second transparent electrode layer 645 extends from its left side A, right side B, upper side C, and lower side D towards its center where a voltage (current) is applied. (See reference...) Figure 3 The first transparent electrode layer 644 and the second transparent electrode layer 645 are electrically connected to each other through connecting electrodes 146 that respectively fill multiple contact holes 645b.

[0136] In addition, such as Figure 9A and Figure 9B As shown, the linewidth d1 between the first openings 644a of the first transparent electrode layer 644 is narrower than the linewidth d2 between the second openings 645a of the second transparent electrode layer 645. Therefore, the resistance of the first transparent electrode layer 644 is greater than the resistance of the second transparent electrode layer 645.

[0137] Therefore, when a voltage (current) is applied to the second transparent electrode layer 645, the first transparent electrode layer 644 can generate heat.

[0138] Because a voltage (current) is applied to the left side A, right side B, upper side C, and lower side D of the second transparent electrode layer 645, the voltage (current) gradually decreases as the second transparent electrode layer 645 extends towards its center due to the surface resistance of the second transparent electrode layer 645. However, because the density of the plurality of contact holes 645b gradually increases as the second transparent electrode layer 645 extends from its left side A, right side B, upper side C, and lower side D towards its center, the first transparent electrode layer 644 can generate heat uniformly throughout its entire region.

[0139] Figure 10A This is a plan view of the second transparent electrode layer according to the seventh embodiment of this disclosure. Figure 10B This is a plan view of the first transparent electrode layer according to the seventh embodiment of this disclosure. Figure 10A and Figure 10B An embodiment in which voltage (current) is applied to the left side A, right side B, upper side C, and lower side D of the second transparent electrode layer is shown.

[0140] like Figure 10A As shown, a second transparent electrode layer (denoted by reference numeral "745") according to a seventh embodiment of the present disclosure is disposed between the intermediate layer 142 and the upper layer 143 of the flexible substrate 140. The second transparent electrode layer 745 includes a plurality of second opening portions 745a. The plurality of second opening portions 745a have uniform dimensions and are disposed at a uniform density.

[0141] like Figure 10B As shown, a first transparent electrode layer (denoted by reference numeral "744") according to a seventh embodiment of the present disclosure is disposed on the back surface of the lower layer 141 of the flexible substrate 140. The first transparent electrode layer 744 includes a plurality of first openings 744a. Each of the plurality of first openings 744a has a quadrilateral ring shape. The plurality of first openings 744a have different sizes, and the smaller first openings are sequentially disposed within the outermost first opening with the largest size such that the smaller first openings are disposed within the larger first openings.

[0142] like Figure 10A and Figure 10B As shown, the first transparent electrode layer 744 and the second transparent electrode layer 745 are electrically connected to each other through a plurality of contact holes 745b. The plurality of contact holes 745b are arranged at a uniform density. (See reference...) Figure 3 The first transparent electrode layer 744 and the second transparent electrode layer 745 can be electrically connected to each other through connection electrodes 146 that respectively fill multiple contact holes 745b.

[0143] like Figure 10A and Figure 10B As shown, the linewidth d1 between the first openings 744a of the first transparent electrode layer 744 is narrower than the linewidth d2 between the second openings 745a of the second transparent electrode layer 745. Therefore, the resistance of the first transparent electrode layer 744 is greater than the resistance of the second transparent electrode layer 745.

[0144] Therefore, when a voltage (current) is applied to the second transparent electrode layer 745, the first transparent electrode layer 744 can generate heat.

[0145] Furthermore, the dimensions of the plurality of first opening portions 744a of the first transparent electrode layer 744 and the linewidth between the first opening portions 744a of the first transparent electrode layer 744 can vary according to the direction of voltage (current) application.

[0146] For example, when assuming a voltage (current) is applied to the left side A, right side B, upper side C, and lower side D of the second transparent electrode layer 745, the widths of the plurality of first opening portions 744a of the first transparent electrode layer 744 are the same, and the linewidth between the first opening portions 744a of the first transparent electrode layer 744 can gradually decrease as the first transparent electrode layer 744 extends from the region corresponding to the applied voltage (current) on the left side A, right side B, upper side C, and lower side D towards its central region. For example, when assuming the linewidth between the first opening portions 744a of the first transparent electrode layer 744 is “d1” in the region corresponding to the applied voltage (current) on the left side A, right side B, upper side C, and lower side D, and the linewidth between the first opening portions 744a of the first transparent electrode layer 744 is “d3” in the central region, d1 is greater than d3.

[0147] Therefore, even when the resistance of the second transparent electrode layer 745 changes in the direction of voltage (current) application, the first transparent electrode layer 744 can generate heat uniformly because the linewidth of the first transparent electrode layer 744 changes according to the direction of voltage (current) application.

[0148] exist Figure 10A and Figure 10B In the seventh embodiment of this disclosure shown, the width of the plurality of first opening portions 744a of the first transparent electrode layer 744 may also gradually decrease as the first transparent electrode layer 744 extends from the regions corresponding to the left side A, right side B, upper side C and lower side D where the applied voltage (current) is applied toward its central region.

[0149] In the following, a method for manufacturing a display device according to one embodiment of the present disclosure will be described.

[0150] Flexible display devices utilize flexible substrates, which possess flexible properties. For this reason, it is difficult to form a reference on the flexible substrate. Figure 2 The multi-buffer layer 151, thin-film transistor Tr, light-emitting diode D, and encapsulation film 180 are described.

[0151] For this reason, the process is performed under conditions where a plastic substrate is attached to one surface of a carrier substrate, such as a glass substrate. After this process is completed, the carrier substrate is separated from the plastic substrate, and thus, a display device is manufactured.

[0152] When separating the carrier substrate from the plastic substrate using laser irradiation, the surface of the plastic substrate may be damaged. Furthermore, impacts may occur during substrate separation, potentially damaging the components.

[0153] In one embodiment of this disclosure, a transparent electrode layer is disposed on a flexible substrate, and a voltage (current) is applied to the transparent electrode layer, causing the transparent electrode layer to generate heat. The heat (Joule heating) generated by the transparent electrode layer allows the carrier substrate to be easily separated from the flexible substrate.

[0154] Figure 11 This is a cross-sectional view illustrating a method of manufacturing a display device according to one embodiment of the present disclosure.

[0155] A separation layer 101 is formed on the carrier substrate 100. Since the separation layer 101 acts as a sacrificial layer, it is formed to have a small thickness. For example, the separation layer 101 is formed to have a thickness of about 1 μm.

[0156] A transparent conductive material, such as indium tin oxide (ITO) or indium zinc oxide (IZO), is deposited on the separation layer 101 and then patterned to form a first transparent electrode layer 144. The first transparent electrode layer 144 has the following characteristics as shown in the reference diagram. Figure 4B , Figure 5B , Figure 6B , Figure 7B , Figure 8B , Figure 9B or Figure 10B The described multiple openings 144a, 244a, 344a, 444a, 544a, 644a or 744a with various patterns.

[0157] Sequentially formed on the first transparent electrode layer 144 as shown in the reference Figure 3 The described flexible substrate 140 includes a lower layer 141 and an intermediate layer 142.

[0158] The lower layer 141 and the intermediate layer 142 are selectively removed to form a plurality of contact holes. A transparent conductive material, such as indium tin oxide (ITO) or indium zinc oxide (IZO), is deposited on the intermediate layer 142 and then patterned to form a second transparent electrode layer 145, such that the second transparent electrode layer 145 is electrically connected to the first transparent electrode layer 144 through the plurality of contact holes. The second transparent electrode layer 145 has as shown in the reference. Figure 4A , Figure 5A , Figure 6A , Figure 7A , Figure 8A , Figure 9A or Figure 10A The description describes multiple openings 145a, 245a, 345a, 445a, 545a, 645a, or 745a with various patterns. Multiple contact holes are also formed with various densities, as shown in the reference. Figure 4A , Figure 5A , Figure 6A , Figure 7A , Figure 8A , Figure 9A and Figure 10A As described.

[0159] An upper layer 143 of the flexible substrate 140 is formed on the second transparent electrode layer 145.

[0160] The materials of the lower layer 141, the middle layer 142, and the upper layer 143 of the flexible substrate 140 are consistent with the reference. Figure 3 The descriptions are the same.

[0161] Multiple buffer layers 151 are formed on the upper layer 143 of the flexible substrate 140.

[0162] For reference Figure 2 As described, a pixel layer 131, on which a thin-film transistor Tr and a light-emitting diode D are sequentially formed, and an encapsulation film 180 is formed on a multi-buffer layer 151.

[0163] For reference Figures 4A to 10B As described, a voltage (current) is applied to the second transparent electrode layer 145, causing the first transparent electrode layer 144 to generate heat and melt the separation layer 101. Thereafter, the carrier substrate 100 is separated from the flexible substrate 140.

[0164] As described above, since the carrier substrate 100 is separated from the flexible substrate 140 under the condition of heat generated by the first transparent electrode layer 144, the flexible substrate 140 is free of foreign matter or scratches from the carrier substrate 100.

[0165] Therefore, damage to the surface of the flexible substrate 140 can be prevented, and damage to the components caused by impacts generated during the separation of the carrier substrate 100 from the flexible substrate 140 can be prevented.

[0166] In addition, the first transparent electrode layer and the second transparent electrode layer can be used as heat sinks for the display device.

[0167] According to the above disclosure, product costs can be reduced because the number of display device failures is reduced.

[0168] According to this disclosure, environmental / social / governance (ESG) objectives that can reduce product costs can be achieved.

[0169] The display device according to various embodiments of this disclosure can be described as follows.

[0170] A flexible substrate according to one embodiment of the present disclosure may include: a first substrate layer made of a conductive material and having a plurality of first opening portions; a second substrate layer disposed on the first substrate layer and having a plurality of contact holes; a third substrate layer disposed on the second substrate layer and electrically connected to the first substrate layer through a plurality of contact holes, the third substrate layer being made of a conductive material and having a plurality of second opening portions; and a fourth substrate layer disposed on the third substrate layer.

[0171] According to one embodiment of this disclosure, the second substrate layer may include a plastic material and an inorganic insulating layer, the fourth substrate layer may include a plastic material, and the first substrate layer and the third substrate layer may each include a transparent electrode layer.

[0172] According to one embodiment of this disclosure, the resistance of the first substrate layer may be greater than the resistance of the third substrate layer.

[0173] According to one embodiment of the present disclosure, the linewidth of the first substrate layer between a plurality of first opening portions may be narrower than the linewidth of the third substrate layer between a plurality of second opening portions.

[0174] According to one embodiment of this disclosure, a plurality of first openings in the first substrate layer can have uniform dimensions and can be arranged at a uniform density. A plurality of contact holes can be arranged at a uniform density. A plurality of second openings in the third substrate layer can have uniform dimensions and can be arranged at a uniform density. The size of the first openings can be smaller than the size of the second openings. The number of the plurality of first openings can be greater than the number of the plurality of second openings. The density of the plurality of first openings can be higher than the density of the plurality of second openings.

[0175] According to one embodiment of this disclosure, a plurality of contact holes can be arranged at a uniform density, and a plurality of second opening portions of the third substrate layer can have uniform dimensions and can be arranged at a uniform density. The size of the first opening portion can be smaller than the size of the second opening portion. The number of the plurality of first opening portions can be greater than the number of the plurality of second opening portions. The density of the plurality of first opening portions can be higher than the density of the plurality of second opening portions. The linewidth of the first substrate layer between the dimensions of the plurality of first opening portions and the plurality of first opening portions can vary according to the direction of voltage or current application.

[0176] According to one embodiment of this disclosure, a voltage or current can be applied to one side of the third substrate layer, and the size of the plurality of first opening portions can gradually decrease as the first substrate layer extends from the region corresponding to the side to which the voltage or current is applied in a direction opposite to the voltage or current application region. The density of the plurality of first opening portions can gradually increase as the first substrate layer extends from the voltage or current application region in a direction opposite to the voltage or current application region. The linewidth of the first substrate layer between the plurality of first opening portions can gradually decrease as the first substrate layer extends from the voltage or current application region in a direction opposite to the voltage or current application region.

[0177] According to one embodiment of this disclosure, a plurality of first openings in the first substrate layer can have uniform dimensions and be arranged at a uniform density, and a plurality of second openings in the third substrate layer can have uniform dimensions and be arranged at a uniform density. The size of the first openings can be smaller than the size of the second openings. The number of the plurality of first openings can be greater than the number of the plurality of second openings. The density of the plurality of first openings can be higher than the density of the plurality of second openings. The density of the plurality of contact holes can vary depending on the direction of voltage or current application.

[0178] According to one embodiment of the present disclosure, a voltage or current can be applied to one side of the third substrate layer, and the density of the plurality of contact holes can gradually increase as the second substrate layer extends from the region corresponding to the side to which the voltage or current is applied in a direction opposite to the region to which the voltage or current is applied.

[0179] According to one embodiment of this disclosure, a voltage or current can be applied to the upper, lower, left, and right sides of the third substrate layer. A plurality of first openings in the first substrate layer can have uniform dimensions and be arranged at a uniform density, and a plurality of second openings in the third substrate layer can also have uniform dimensions and be arranged at a uniform density. The size of the first openings can be smaller than the size of the second openings. The number of the plurality of first openings can be greater than the number of the plurality of second openings. The density of the plurality of first openings can be higher than the density of the plurality of second openings. The density of the plurality of contact holes can vary depending on the direction of voltage or current application.

[0180] According to one embodiment of this disclosure, the density of the plurality of contact holes may gradually increase as the second substrate layer extends from the regions corresponding to the upper, lower, left and right sides to which the applied voltage or current is applied toward its central region.

[0181] According to one embodiment of this disclosure, a voltage or current can be applied to the upper, lower, left, and right sides of a third substrate layer. Multiple contact holes can be arranged at a uniform density, and multiple second opening portions of the third substrate layer can have uniform dimensions and be arranged at a uniform density. The size of the first opening portion can be smaller than the size of the second opening portion. The number of multiple first opening portions can be greater than the number of multiple second opening portions. The density of the multiple first opening portions can be higher than the density of the multiple second opening portions. The size of the multiple first opening portions and the linewidth of the first substrate layer between the multiple first opening portions can vary according to the direction of voltage or current application.

[0182] According to one embodiment of this disclosure, the size of the plurality of first openings can gradually decrease as the first substrate layer extends from the regions corresponding to the applied voltage or current on its upper, lower, left, and right sides towards its central region. The density of the plurality of first openings can gradually increase as the first substrate layer extends from the regions corresponding to the applied voltage or current on its upper, lower, left, and right sides towards its central region. The linewidth of the first substrate layer between the plurality of first openings can gradually decrease as the first substrate layer extends from the regions corresponding to the applied voltage or current on its upper, lower, left, and right sides towards its central region.

[0183] According to one embodiment of this disclosure, each of the plurality of first openings in the first substrate layer may have a quadrilateral ring shape, and the plurality of first openings may each have different sizes, wherein smaller first openings may be sequentially disposed within the outermost first opening with the largest size, such that the smaller first openings are disposed within the larger first openings. The linewidth of the first substrate layer among the plurality of first openings may be uniform. The plurality of second openings in the third substrate layer may have uniform sizes and may be disposed at a uniform density. The density of the plurality of contact holes may vary depending on the direction of voltage or current application.

[0184] According to one embodiment of this disclosure, a voltage or current can be applied to the upper, lower, left, and right sides of the third substrate layer, and the density of the plurality of contact holes can gradually increase as the second substrate layer extends from the regions corresponding to the upper, lower, left, and right sides to which the applied voltage or current is applied toward its central region.

[0185] According to one embodiment of this disclosure, each of the plurality of first openings in the first substrate layer may have a quadrilateral ring shape, and the plurality of first openings may each have different sizes, wherein smaller first openings may be sequentially disposed within the outermost first opening with the largest size, such that the smaller first openings are disposed within the larger first openings. The plurality of contact holes may be arranged at a uniform density. The plurality of second openings in the third substrate layer may have uniform sizes and may be arranged at a uniform density. The sizes of the plurality of first openings and the linewidth of the first substrate layer between the plurality of first openings may vary depending on the direction of voltage or current application.

[0186] According to one embodiment of this disclosure, a voltage or current can be applied to the upper, lower, left, and right sides of the third substrate layer, and the dimensions of the plurality of first openings can gradually decrease as the first substrate layer extends from its regions corresponding to the applied voltage or current to its central region. The linewidth of the first substrate layer between the plurality of first openings can gradually decrease as the first substrate layer extends from its regions corresponding to the applied voltage or current to its central region.

[0187] A display device according to one embodiment of the present disclosure may include a flexible substrate according to one embodiment of the present disclosure, a thin-film transistor on the flexible substrate, an organic light-emitting diode connected to the thin-film transistor, and an encapsulation film disposed on the organic light-emitting diode.

[0188] A method for manufacturing a display device according to one embodiment of the present disclosure may include: forming a separation layer on a carrier substrate; forming a first substrate layer on the separation layer, which is made of a conductive material and has a plurality of first openings; forming a second substrate layer on the first substrate layer, which has a plurality of contact holes; forming a third substrate layer on the second substrate layer, which is electrically connected to the first substrate layer through the plurality of contact holes and is made of a conductive material, the third substrate layer having a plurality of second openings; forming a fourth substrate layer on the third substrate layer; sequentially forming a pixel layer having thin-film transistors and light-emitting diodes and an encapsulation film on the fourth substrate layer; and separating the carrier substrate by applying a voltage or current to the third substrate layer to generate heat in the first substrate layer.

[0189] The above disclosure is not limited to the above embodiments and drawings. Therefore, those skilled in the art will understand that various substitutions, changes, and modifications can be made without departing from the scope of this disclosure.

Claims

1. A flexible substrate, comprising: A first substrate layer made of a conductive material and having a plurality of first opening portions; A second substrate layer disposed on the first substrate layer and having a plurality of contact holes; A third substrate layer disposed on the second substrate layer and electrically connected to the first substrate layer through the plurality of contact holes, the third substrate layer being made of a conductive material and having a plurality of second opening portions; as well as A fourth substrate layer is disposed on the third substrate layer.

2. The flexible substrate according to claim 1, wherein: The second substrate layer includes a plastic material and an inorganic insulating layer; The fourth substrate layer comprises a plastic material; and The first substrate layer and the third substrate layer each include a transparent electrode layer.

3. The flexible substrate according to claim 1, wherein the resistance of the third substrate layer is less than the resistance of the first substrate layer.

4. The flexible substrate according to claim 1, wherein the linewidth of the first substrate layer between the plurality of first opening portions is narrower than the linewidth of the third substrate layer between the plurality of second opening portions.

5. The flexible substrate according to claim 4, wherein: The plurality of first openings in the first substrate layer have uniform size and are arranged at a uniform density; The plurality of contact holes are arranged at a uniform density; The plurality of second openings in the third substrate layer have uniform size and are arranged at a uniform density; The size of the first opening is smaller than the size of the second opening. The number of the plurality of first opening portions is greater than the number of the plurality of second opening portions; as well as The density of the plurality of first opening portions is higher than the density of the plurality of second opening portions.

6. The flexible substrate according to claim 4, wherein: The plurality of contact holes are arranged at a uniform density; The plurality of second openings in the third substrate layer have uniform size and are arranged at a uniform density; The size of the first opening is smaller than the size of the second opening. The number of the plurality of first opening portions is greater than the number of the plurality of second opening portions; The density of the plurality of first opening portions is higher than the density of the plurality of second opening portions; as well as The dimensions of the plurality of first openings in the first substrate layer and the linewidth between the plurality of first openings vary according to the direction of voltage or current application.

7. The flexible substrate according to claim 6, wherein: Apply a voltage or current to one side of the third substrate layer; The size of the plurality of first opening portions gradually decreases as the first substrate layer extends from the region corresponding to the side on which the voltage or current is applied in a direction opposite to the region where the voltage or current is applied. The density of the plurality of first openings gradually increases as the first substrate layer extends from the voltage or current application region in a direction opposite to the voltage or current application region; and The linewidth of the first substrate layer between the plurality of first opening portions gradually decreases as the first substrate layer extends from the voltage or current application region in a direction opposite to the voltage or current application region.

8. The flexible substrate according to claim 4, wherein: The plurality of first openings in the first substrate layer have uniform size and are arranged at a uniform density; The plurality of second openings in the third substrate layer have uniform size and are arranged at a uniform density; The size of the first opening is smaller than the size of the second opening. The number of the plurality of first opening portions is greater than the number of the plurality of second opening portions; The density of the plurality of first opening portions is higher than the density of the plurality of second opening portions; as well as The density of the plurality of contact holes varies depending on the direction of voltage or current application.

9. The flexible substrate according to claim 8, wherein: Applying a voltage or current to one side of the third substrate layer; and The density of the plurality of contact holes gradually increases as the second substrate layer extends from the region corresponding to the side on which the voltage or current is applied in a direction opposite to the region where the voltage or current is applied.

10. The flexible substrate according to claim 4, wherein: In a plan view of the flexible substrate, voltage or current is applied to the upper, lower, left, and right sides of the third substrate layer; The plurality of first openings in the first substrate layer have uniform size and are arranged at a uniform density; The plurality of second openings in the third substrate layer have uniform size and are arranged at a uniform density; The size of the first opening is smaller than the size of the second opening. The number of the plurality of first opening portions is greater than the number of the plurality of second opening portions; The density of the plurality of first opening portions is higher than the density of the plurality of second opening portions; as well as The density of the plurality of contact holes varies depending on the direction of voltage or current application.

11. The flexible substrate of claim 10, wherein the density of the plurality of contact holes gradually increases as the second substrate layer extends from its regions corresponding to the upper, lower, left and right sides to which the voltage or current is applied toward its central region.

12. The flexible substrate according to claim 4, wherein: In a plan view of the flexible substrate, voltage or current is applied to the upper, lower, left, and right sides of the third substrate layer; The plurality of contact holes are arranged at a uniform density; The plurality of second openings in the third substrate layer have uniform size and are arranged at a uniform density; The size of the first opening is smaller than the size of the second opening. The number of the plurality of first opening portions is greater than the number of the plurality of second opening portions; The density of the plurality of first opening portions is higher than the density of the plurality of second opening portions; as well as The dimensions of the plurality of first openings in the first substrate layer and the linewidth between the plurality of first openings vary according to the direction of voltage or current application.

13. The flexible substrate according to claim 12, wherein: The size of the plurality of first openings gradually decreases as the first substrate layer extends from the regions corresponding to the upper, lower, left, and right sides to which the voltage or current is applied toward its central region. The density of the plurality of first openings gradually increases as the first substrate layer extends from its regions corresponding to the upper, lower, left, and right sides where the voltage or current is applied towards its central region; and The linewidth of the first substrate layer between the plurality of first opening portions gradually decreases as the first substrate layer extends from its regions corresponding to the upper, lower, left, and right sides to which the voltage or current is applied toward its central region.

14. The flexible substrate according to claim 4, wherein: Each of the plurality of first opening portions of the first substrate layer has a quadrilateral ring shape; The plurality of first opening portions have different sizes, and the smaller first opening portions are arranged sequentially within the outermost first opening portion having the largest size, such that the smaller first opening portions are disposed within the larger first opening portions. The linewidth of the first substrate layer is uniform among the plurality of first opening portions; The plurality of second openings in the third substrate layer have uniform size and are arranged at a uniform density; and The density of the plurality of contact holes varies depending on the direction of voltage or current application.

15. The flexible substrate according to claim 14, wherein: In a plan view of the flexible substrate, voltage or current is applied to the upper, lower, left, and right sides of the third substrate layer; and The density of the plurality of contact holes gradually increases as the second substrate layer extends from its regions corresponding to the upper, lower, left, and right sides to which the voltage or current is applied toward its central region.

16. The flexible substrate according to claim 4, wherein: Each of the plurality of first opening portions of the first substrate layer has a quadrilateral ring shape; The plurality of first opening portions have different sizes, and the smaller first opening portions are arranged sequentially within the outermost first opening portion having the largest size, such that the smaller first opening portions are disposed within the larger first opening portions. The plurality of contact holes are arranged at a uniform density; The plurality of second openings in the third substrate layer have uniform size and are arranged at a uniform density; as well as The dimensions of the plurality of first openings in the first substrate layer and the linewidth between the plurality of first openings vary according to the direction of voltage or current application.

17. The flexible substrate according to claim 16, wherein: In a plan view of the flexible substrate, voltage or current is applied to the upper, lower, left, and right sides of the third substrate layer; The dimensions of the plurality of first openings gradually decrease as the first substrate layer extends from its regions corresponding to the upper, lower, left, and right sides where the voltage or current is applied towards its central region; and The linewidth of the first substrate layer between the plurality of first opening portions gradually decreases as the first substrate layer extends from its regions corresponding to the upper, lower, left, and right sides to which the voltage or current is applied toward its central region.

18. The flexible substrate according to claim 1, wherein: The flexible substrate includes a lower layer, an intermediate layer, and an upper layer. A first transparent electrode layer is disposed on the back surface of the lower layer, and a second transparent electrode layer is disposed between the intermediate layer and the upper layer. Wherein the first transparent electrode layer serves as the first substrate layer, the lower layer and the middle layer serve as the second substrate layer, the second transparent electrode layer serves as the third substrate layer, and the upper layer serves as the fourth substrate layer; and The first transparent electrode layer and the second transparent electrode layer are electrically connected to each other through contact holes provided in the lower layer and the middle layer.

19. A method of manufacturing a display device, comprising: A separation layer is formed on the carrier substrate; A first substrate layer made of conductive material and having a plurality of first opening portions is formed on the separation layer; A second substrate layer having a plurality of contact holes is formed on the first substrate layer; A third substrate layer made of conductive material is formed on the second substrate layer and electrically connected to the first substrate layer through the plurality of contact holes. The third substrate layer has a plurality of second opening portions. A fourth substrate layer is formed on the third substrate layer; A pixel layer having thin-film transistors and light-emitting diodes, and an encapsulation film are sequentially formed on the fourth substrate layer; as well as The carrier substrate is separated by applying voltage or current to the third substrate layer to generate heat in the first substrate layer.

20. The method of claim 19, wherein: The second substrate layer includes a plastic material and an inorganic insulating layer; The fourth substrate layer comprises a plastic material; and The first substrate layer and the third substrate layer each include a transparent electrode layer. The resistance of the third substrate layer is less than the resistance of the first substrate layer, and The linewidth of the first substrate layer between the plurality of first opening portions is narrower than the linewidth of the third substrate layer between the plurality of second opening portions.

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