Display device and method of manufacturing the same

Abstract

The display device includes a display substrate, a light-emitting device, an encapsulation layer above the display substrate and encapsulating the light-emitting device, a filling layer on the encapsulation layer, a first covering layer on the filling layer, a relative substrate on the first covering layer, and a diffraction grating layer arranged between the first covering layer and the relative substrate, wherein the diffraction grating layer includes a plurality of diffraction patterns spaced a certain distance from each other, and the plurality of diffraction patterns protrude from the surface of the relative substrate in a direction perpendicular to the relative substrate, and the surface of the relative substrate faces the display substrate. The present invention also discloses a method for manufacturing the display device.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Korean Patent Application No. 10-2018-0098762 filed on August 23, 2018, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] One or more embodiments relate to a display device that can be used for a head-mounted display device and a method of manufacturing the display device. Background Art

[0004] With the rapid development of the display field capable of intuitively displaying various electrical signal information, various display devices with excellent characteristics such as thin profile, light weight and low power consumption are being studied and developed. In addition, recently, due to the increasing interest in wearable devices, head-mounted display devices have begun to be introduced. The head-mounted display device can be worn on the head or eyes of the user to display images in front of the user's eyes so that the user can experience virtual reality or augmented reality. The head-mounted display device may include a lens for expanding the image displayed at a position between the display device and the user's eyes through the display device, thereby providing the image in front of the user's eyes. However, when the image is expanded by the lens, a screen door effect (SDE) may occur in which a non-luminous area of ​​the display device is recognized by the user. Summary of the invention

[0005] One or more embodiments include a display device configured to provide a high-quality image by resolving a screen door effect when a head-mounted display device is implemented, and a method of manufacturing the display device.

[0006] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the presented embodiments.

[0007] According to one or more embodiments, a display device includes: a display substrate; a light-emitting device on the display substrate; an encapsulation layer arranged above the display substrate and encapsulating the light-emitting device; a filling layer on the encapsulation layer; a first covering layer on the filling layer; a relative substrate on the first covering layer; and a diffraction grating layer between the first covering layer and the relative substrate, wherein the diffraction grating layer includes a plurality of diffraction patterns spaced a certain distance from each other, and the plurality of diffraction patterns protrude from a surface of the relative substrate in a direction perpendicular to the relative substrate, and the surface of the relative substrate faces the display substrate.

[0008] The display device may further include a second covering layer between the encapsulation layer and the filling layer.

[0009] The thickness of the second cover layer may be greater than the thickness of the first cover layer.

[0010] The first cover layer may include the same material as that of the second cover layer.

[0011] The plurality of diffraction patterns may be arranged at the same period in a first direction and a second direction perpendicularly intersecting each other.

[0012] The encapsulation layer may include a first inorganic encapsulation layer, an organic encapsulation layer, and a second inorganic encapsulation layer stacked in sequence.

[0013] Light generated from the light emitting device may pass through the diffraction grating layer to expand the light emitting area.

[0014] The display substrate may include a base substrate and a thin film transistor, which is arranged above the base substrate and electrically connected to the light-emitting device, and the light-emitting device may be an organic light-emitting diode, which has a pixel electrode electrically connected to the thin film transistor, a relative electrode above the pixel electrode, and an intermediate layer between the pixel electrode and the relative electrode and including an emission layer.

[0015] The base substrate and the opposite substrate may each include polyimide.

[0016] The plurality of diffraction patterns may diffract light generated by the light emitting device to generate a reference light emission pattern and a plurality of duplicate light emission patterns.

[0017] According to one or more embodiments, a method for manufacturing a display device includes: forming a light-emitting device on a display substrate; forming an encapsulation layer on the display substrate to encapsulate the light-emitting device; forming a diffraction grating layer on a surface of a relative substrate; forming a first covering layer on the diffraction grating layer; and arranging the relative substrate so that the diffraction grating layer faces the display substrate, and then attaching the relative substrate to the display substrate using a filling layer, wherein the diffraction grating layer protrudes from the surface of the relative substrate in a direction perpendicular to the relative substrate and includes a plurality of diffraction patterns spaced apart from each other, and the first covering layer is formed on the plurality of diffraction patterns and on the surface of the relative substrate between the plurality of diffraction patterns.

[0018] The plurality of diffraction patterns may be arranged at the same interval in a first direction and a second direction perpendicularly intersecting each other.

[0019] The method may further include, before attaching the opposite substrate to the display substrate, forming a second cover layer on the encapsulation layer.

[0020] The thickness of the second cover layer may be greater than the thickness of the first cover layer.

[0021] The first cover layer may include the same material as that of the second cover layer.

[0022] The display substrate may include a base substrate and a thin film transistor, which is arranged above the base substrate and electrically connected to the light-emitting device, and the base substrate may be formed on a first carrier substrate, and after attaching the relative substrate to the display substrate, the first carrier substrate may be separated from the base substrate.

[0023] The light emitting device may be an organic light emitting diode having a pixel electrode electrically connected to the thin film transistor, an opposite electrode over the pixel electrode, and an intermediate layer between the pixel electrode and the opposite electrode and including an emission layer.

[0024] The opposing substrate may be formed on the second carrier substrate, and after attaching the opposing substrate to the display substrate, the second carrier substrate may be separated from the opposing substrate.

[0025] The base substrate and the opposite substrate may each include polyimide.

[0026] The encapsulation layer may be formed by sequentially stacking a first inorganic encapsulation layer, an organic encapsulation layer, and a second inorganic encapsulation layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] These and / or other aspects will become apparent and more readily understood from the following description of embodiments in conjunction with the accompanying drawings, in which:

[0028] Figure 1 is a schematic cross-sectional view illustrating an example of a display device according to an embodiment;

[0029] Figure 2 Yes Description Figure 1 A schematic cross-sectional view of an example of a display substrate and a light-emitting device included in a display device of ;

[0030] Figure 3 Yes Description Figure 1 A schematic perspective view of an example of a diffraction grating layer of a display device;

[0031] Figure 4 is a simulation diagram used to explain the expansion of the luminous area, which is caused by Figure 1 The diffraction grating layer of the display device is performed;

[0032] Figure 5 The description includes Figure 1 A schematic cross-sectional view of an example of a head mounted display device of a display device;

[0033] Figure 6 and Figure 7 It indicates manufacturing Figure 1 A schematic cross-sectional view of a method for displaying a device;

[0034] Figure 8is a schematic cross-sectional view illustrating an example of a display device according to another embodiment; and

[0035] Fig. 9 and Fig.10 It indicates manufacturing Figure 8 A schematic cross-sectional view of a method for displaying a device. DETAILED DESCRIPTION

[0036] Reference will now be made in detail to embodiments, examples of which are shown in the accompanying drawings, wherein the same reference numerals refer to the same elements throughout. In this regard, embodiments of the present invention may have different forms and should not be construed as being limited to the descriptions set forth herein. Therefore, embodiments are described below only by reference to the accompanying drawings to explain various aspects of this specification. As used herein, the term "and / or" includes any and all combinations of one or more of the related listed items. For example, the expression "at least one" when preceding a column of elements modifies the entire column of elements, without modifying the individual elements of the column.

[0037] Since the present disclosure allows for various variations and multiple embodiments, specific embodiments will be illustrated in the drawings and described in detail in the written description. The effects and features of the present disclosure and methods for achieving the effects and features will become apparent to those skilled in the art from the following detailed description of various embodiments of the present disclosure in conjunction with the drawings. However, the present disclosure may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0038] It should be understood that although the terms "first", "second", etc. may be used herein to describe various components, these components should not be limited by these terms. These components are only used to distinguish one component from another component.

[0039] As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0040] It should be further understood that the terms “comprise” and / or “include” used herein indicate the presence of recited features or components, but do not preclude the presence or addition of one or more other features or components.

[0041] It will be understood that when a layer, region or component is referred to as being “formed on” another layer, region or component, it may be directly or indirectly formed on the other layer, region or component. That is, for example, intervening layers, regions or components may be present.

[0042] For the convenience of explanation, the sizes of the elements in the drawings may be exaggerated. In other words, since the sizes and thicknesses of the elements in the drawings are arbitrarily shown for the convenience of explanation, the following embodiments are not limited thereto.

[0043] When a certain embodiment can be implemented differently, the specific process order can be performed in a different order than described. For example, two processes described in succession can be performed substantially simultaneously, or in a reverse order to the described order.

[0044] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, in which the same reference numerals denote the same elements.

[0045] Figure 1 is a schematic cross-sectional view illustrating an example of a display device 100 according to an embodiment. Figure 2 Yes Description Figure 1 Schematic cross-sectional view of an example of a display substrate 110 and a light emitting device included in a display device 100 of FIG.

[0046] See also Figure 1 and Figure 2 According to one embodiment, the display device 100 may include a display substrate 110, a light emitting device disposed on the display substrate 110, an encapsulation layer 160 disposed on the light emitting device, a filling layer 230 disposed on the encapsulation layer 160, a first cover layer 220 disposed on the filling layer 230, a diffraction grating layer 170 disposed on the first cover layer 220, and an opposite substrate 210 disposed on the diffraction grating layer 170. Hereinafter, the light emitting device is described as an organic light emitting diode OLED having a pixel electrode 121, an opposite electrode 150, and an intermediate layer 141 disposed between the pixel electrode 121 and the opposite electrode 150 and including an emission layer. However, the present disclosure is not limited thereto, and the display device 100 may include various types of light emitting devices.

[0047] The display substrate 110 may include a base substrate 101 and a thin film transistor TFT disposed over the base substrate 101 and electrically connected to the organic light emitting diode OLED. In addition, the display substrate 110 may include a capacitor and electronic devices required to drive the organic light emitting diode OLED.

[0048] The base substrate 101 may be an insulating substrate. For example, the base substrate 101 may be made of silicon dioxide (SiO 2 ) as a main component. However, the base substrate 101 is not limited thereto and may be formed of a transparent plastic material. The plastic material may be polyethersulfone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyarylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC) or cellulose acetate propionate (CAP), etc.

[0049] In addition, when the display device 100 is a top emission type, since the base substrate 101 does not need to be formed of a transparent material, the base substrate 101 may be formed of a metal. When the base substrate 101 is formed of a metal, the base substrate 101 may include iron, chromium (Cr), manganese, nickel (Ni), titanium (Ti), molybdenum (Mo), stainless steel (SUS), Invar alloy, Inconel alloy, Kovar alloy, etc.

[0050] The buffer layer 112 may be disposed on the base substrate 101. The buffer layer 112 may provide a flat surface to the upper portion of the base substrate 101 and prevent foreign matter from penetrating the base substrate 101 into the organic light emitting diode OLED. For example, the buffer layer 112 may include an inorganic material (such as silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, titanium oxide or titanium nitride, etc.) or an organic material (such as polyimide, polyester or acrylic, etc.). Alternatively, the buffer layer 112 may be formed by stacking a stack formed by stacking the above-mentioned multiple materials.

[0051] The thin film transistor TFT is disposed on the buffer layer 112. The thin film transistor TFT includes a semiconductor layer A (including amorphous silicon, polycrystalline silicon or an organic semiconductor material), a gate electrode G, a source electrode S and a drain electrode D.

[0052] The gate electrode G is arranged on the semiconductor layer A. According to the signal applied to the gate electrode G, the source electrode S is electrically connected to the drain electrode D. The gate electrode G may include, for example, one or more materials of aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), Ni, neodymium (Nd), iridium (Ir), Cr, lithium (Li), calcium (Ca), Mo, Ti, tungsten (W) and copper (Cu). The gate electrode G may have a single layer or a multilayer structure. In order to ensure insulation between the semiconductor layer A and the gate electrode G, the gate insulating layer 113 may be formed of an inorganic material such as silicon oxide, silicon nitride, silicon oxynitride, etc., and is arranged between the semiconductor layer A and the gate electrode G.

[0053] The interlayer insulating layer 114 may be disposed on the gate electrode G. The interlayer insulating layer 114 may be formed of an inorganic material such as silicon oxide, silicon nitride, silicon oxynitride, etc. to have a single-layer or multi-layer structure.

[0054] The source electrode S and the drain electrode D are arranged on the interlayer insulating layer 114. The source electrode S and the drain electrode D are electrically connected to the semiconductor layer A through contact holes arranged in the interlayer insulating layer 114 and the gate insulating layer 113, respectively. Considering conductivity, etc., the source electrode S and the drain electrode D may include, for example, one or more materials of Al, Pt, Pd, Ag, Mg, Au, Ni, Nd, Ir, Cr, Li, Ca, Mo, Ti, W, and Cu. The source electrode S and the drain electrode D may have a single-layer or multi-layer structure.

[0055] In order to protect the thin film transistor TFT etc. having such a structure, a passivation layer (not shown) may be arranged to cover the thin film transistor TFT. The passivation layer may be formed of, for example, an inorganic material such as silicon oxide, silicon nitride, silicon oxynitride, etc. The passivation layer may include a single layer or multiple layers.

[0056] The planarization layer 115 may be disposed on the thin film transistor TFT. Figure 2 As shown, when the organic light emitting diode OLED is arranged at a position above the thin film transistor TFT, the planarization layer 115 may cover the thin film transistor TFT to planarize the uneven surface caused by the thin film transistor TFT. The planarization layer 115 may include an organic material such as acryl, benzocyclobutene (BCB) or hexamethyldisiloxane (HMDSO). Figure 2 It is shown that the planarization layer 115 has a single layer. However, the planarization layer may have multiple layers, or may be variously modified. In this embodiment, the display device 100 may have both the passivation layer and the planarization layer 115, or may have only the planarization layer 115 as needed.

[0057] The organic light emitting diode OLED is arranged on the display substrate 110 to have a pixel electrode 121, an opposite electrode 150, and an intermediate layer 141 arranged between the pixel electrode 121 and the opposite electrode 150. Specifically, a contact hole is arranged in the planarization layer 115 to expose at least one of a source electrode S and a drain electrode D of the thin film transistor TFT. The pixel electrode 121 is arranged on the planarization layer 115 and contacts one of the source electrode S and the drain electrode D through the contact hole, thereby being electrically connected to the thin film transistor TFT.

[0058] The pixel electrode 121 may be a (semi) transparent electrode or a reflective electrode. When the pixel electrode 121 is a (semi) transparent electrode, the pixel electrode 121 may include indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In 2 O 3 ), indium gallium oxide (IGO) or aluminum zinc oxide (AZO). When the pixel electrode 121 is a reflective electrode, the pixel electrode 121 may include a reflective layer formed of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr or a compound thereof, or a reflective layer formed of ITO, IZO, ZnO, In 2 O 3 , IGO or AZO. However, the present disclosure is not limited thereto. The pixel electrode 121 may be variously modified to include various materials and have a single layer or multi-layer structure, etc.

[0059] The pixel defining layer 130 may be disposed on the planarization layer 115. The pixel defining layer 130 has an opening that exposes at least the center of the pixel electrode 121, thereby defining a pixel. Figure 2 In the illustrated case, the pixel defining layer 130 covers the edge of the pixel electrode 121 to increase the distance between the edge of the pixel electrode 121 and the opposing electrode 150 disposed above the pixel electrode 121, thereby preventing arcing, etc. from being generated at the edge of the pixel electrode 121. The pixel defining layer 130 may include an organic material, such as polyimide or hexamethyldisiloxane (HMDSO), etc.

[0060] The intermediate layer 141 of the organic light emitting diode OLED includes an emission layer. The emission layer may include a polymer or a low molecular weight organic material that emits light having a specific color. In addition, the intermediate layer 141 may include at least one functional layer of a hole transport layer (HTL), a hole injection layer (HIL), an electron transport layer (ETL), and an electron injection layer (EIL). The functional layer may include an organic material.

[0061] The opposing electrode 150 may be formed as a whole to cover the plurality of intermediate layers 141, corresponding to the plurality of pixel electrodes 121. The opposing electrode 150 may be a (semi) transparent electrode or a reflective electrode. When the opposing electrode 150 is a (semi) transparent electrode, the opposing electrode 150 may include a layer formed of a metal or a compound thereof having a low work function (i.e., Li, Ca, lithium calcium fluoride (LiF / Ca), lithium aluminum fluoride (LiF / Al), Al, Ag, Mg), or a layer formed of ITO, IZO, ZnO, or In 2 O 3 When the opposing electrode 150 is a reflective electrode, the opposing electrode 150 may have a layer formed of Li, Ca, LiF / Ca, LiF / Al, Al, Ag, Mg, or a compound thereof. However, the composition and material of the opposing electrode 150 are not limited thereto, and various modifications may be made.

[0062] The encapsulation layer 160 is disposed on the opposite electrode 150. The encapsulation layer 160 protects the organic light emitting diode OLED from external moisture or oxygen, etc. As an example, the encapsulation layer 160 may include a first inorganic encapsulation layer 161, an organic encapsulation layer 162, and a second inorganic encapsulation layer 163.

[0063] The first inorganic encapsulating layer 161 covers the opposite electrode 150 and may include silicon oxide, silicon nitride and / or silicon oxynitride. Since the first inorganic encapsulating layer 161 is arranged along the structure arranged therebelow, its upper surface may be uneven, such as Figure 2As shown. Since the organic encapsulation layer 162 covers the first inorganic encapsulation layer 161 and has a sufficient thickness, the upper surface of the organic encapsulation layer 162 may be substantially flat. The organic encapsulation layer 162 may include one or more materials selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polyethylene sulfonate, polyoxymethylene, polyarylate and hexamethyldisiloxane. The second inorganic encapsulation layer 163 covers the organic encapsulation layer 162 and may include silicon oxide, silicon nitride and / or silicon oxynitride. The second inorganic encapsulation layer 163 may extend to the outside of the organic encapsulation layer 162 to contact the first inorganic encapsulation layer 161 so that the organic encapsulation layer 162 is not exposed to the outside.

[0064] Therefore, since the encapsulation layer 160 includes the first inorganic encapsulation layer 161, the organic encapsulation layer 162, and the second inorganic encapsulation layer 163, due to such a multi-layer structure, even if cracks occur in the encapsulation layer 160, the cracks are not connected to each other between the first inorganic encapsulation layer 161 and the organic encapsulation layer 162 or between the organic encapsulation layer 162 and the second inorganic encapsulation layer 163. Therefore, the formation of a path through which external moisture, oxygen, etc. penetrate into the display device 100 can be prevented or minimized.

[0065] A capping layer may be further disposed between the opposite electrode 150 and the encapsulation layer 160 to improve the light coupling efficiency of the light generated by the organic light emitting diode OLED. As an embodiment, the capping layer may be formed of an organic layer or an inorganic layer.

[0066] The filling layer 230 is arranged on the encapsulation layer 160. The filling layer 230 can attach the display substrate 110 (including the organic light emitting diode OLED) to the opposite substrate 210 on which the diffraction grating layer 170 and the like are disposed. Specifically, the filling layer 230 can be arranged between the encapsulation layer 160 and the first cover layer 220 to attach the encapsulation layer 160 to the first cover layer 220. The filling layer 230 may be formed of a silicon-based additive or an acrylic additive, etc., and further include a hardener, a cross-linking agent, an ultraviolet stabilizer, etc. The filling layer 230 may be a pressure-sensitive adhesive (PSA) or an optically transparent additive (OCA), etc. The filling layer 230 may have a thickness of about 10 μm or less.

[0067] The first cover layer 220 separates the organic light emitting diode OLED from the diffraction grating layer 170 by a certain distance. As described below, the area of ​​the replica light emission pattern generated by the diffraction grating layer 170 is determined by the diffraction distance of the light generated by the organic light emitting diode OLED. The distance between the organic light emitting diode OLED and the diffraction grating layer 170 affects the diffraction distance. That is, when the distance between the organic light emitting diode OLED and the diffraction grating layer 170 is too small, for example, when the thickness of the first cover layer 220 is too small, since the area in which the replica light emission pattern is formed becomes smaller, it may be difficult to solve the screen door effect (SDE) when implementing a head-mounted display device. On the other hand, when the distance between the organic light emitting diode OLED and the diffraction grating layer 170 is too large, due to the excessive increase in the diffraction distance, blurring of the color mixed with the light generated by the organic light emitting diode OLED may occur. As an example, when the display device 100 has a resolution of 571ppi, the first cover layer 220 may have a thickness of about 300μm. However, the present disclosure is not limited thereto. The thickness of the first cover layer 220 may be appropriately selected to increase the area where the replicated light emission pattern is formed and balance blurring.

[0068] The first cover layer 220 may be formed of an inorganic material or an organic material having a high refractive index. When the first cover layer 220 is formed of an inorganic material, the first cover layer 220 may include SiO 2 、Silicon Nitride (SiN x )、ZnO 2 ), titanium dioxide (TiO 2 )、ZrO 2 ), at least one of ITO and IZO. When the first covering layer 220 is formed of an organic material, the first covering layer 220 may include acrylic, tris-8-hydroxyquinoline aluminum (Alq 3 ), copper phthalocyanine (CuPc), 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) and N,N′-di(naphthalene-1-yl)-N,N′-diphenylbenzidine (α-NPB).

[0069] The opposite substrate 210 is disposed on the first cover layer 220, and the diffraction grating layer 170 is disposed on a surface of the opposite substrate 210. Here, the diffraction grating layer 170 may be disposed on a surface of the opposite substrate 210 facing the display substrate 110.

[0070] The opposite substrate 210 may be formed of polyimide or acrylate, etc. However, the opposite substrate 210 is not limited thereto. The opposite substrate 210 may be formed of various materials such as PET, PEN, etc. or metal. Depending on the situation, a thin metal foil-like stainless steel (such as SUS) may be used for the opposite substrate 210.

[0071] The diffraction grating layer 170 includes a plurality of diffraction patterns 171 spaced apart from each other by a certain distance, and is arranged in a path of light emitted from the organic light emitting diode OLED to diffract the emitted light, thereby expanding a light emitting area of ​​the organic light emitting diode OLED.

[0072] Although not shown in the figure, an input detector may be further arranged above the encapsulation layer 160. The input detector may be directly formed on the encapsulation layer 160 and include a plurality of detection electrodes to detect contact with an external touch input element (such as a user's hand or a pen, etc.), thereby generating an input signal. Therefore, when the input detector is further arranged above the encapsulation layer 160, the filling layer 230 is arranged between the input detector and the first cover layer 220.

[0073] Figure 3 Yes Description Figure 1 Schematic perspective view of an example of a diffraction grating layer 170 of the display device 100.

[0074] Figure 4 is a simulation diagram used to explain the expansion of the luminous area, which is caused by Figure 1 The diffraction grating layer 170 of the display device 100 is performed.

[0075] The diffraction grating layer 170 is disposed on a surface of the opposite substrate 210. Here, the surface of the opposite substrate 210 on which the diffraction grating layer 170 is disposed may be facing the Figure 1 The surface of the display substrate 110 is provided.

[0076] Each of the plurality of diffraction patterns 171 may protrude from the surface of the opposing substrate 210 in a direction perpendicular to the opposing substrate 210 and have the same shape. As an example, each of the plurality of diffraction patterns 171 may have a cylindrical shape. However, the plurality of diffraction patterns 171 are not limited thereto and may have various shapes, such as a rectangular column shape, respectively.

[0077] The plurality of diffraction patterns 171 may be spaced a certain distance apart from each other. That is, the plurality of diffraction patterns 171 may be arranged on the surface of the opposing substrate 210, respectively, with the same pitch DP1 in the first direction X and the second direction Y. The first direction X may be perpendicular to the second direction Y. The pitch DP1 refers to the distance from the side of the diffraction pattern 171 to the corresponding side of the adjacent diffraction pattern 171. Alternatively, the pitch DP1 may be understood as the distance between the center of the diffraction pattern 171 and the center of the adjacent diffraction pattern 171 along the first direction X and the second direction Y.

[0078] The first cover layer 220 is disposed on the diffraction grating layer 170. Since the diffraction grating layer 170 includes a plurality of diffraction patterns 171 spaced apart from each other, the first cover layer 220 is disposed not only on the plurality of diffraction patterns 171 but also on the surface of the opposing substrate 210 between the plurality of diffraction patterns 171. That is, the plurality of diffraction patterns 171 may have a shape extending into the first cover layer 220.

[0079] like Figure 4 As shown, the plurality of diffraction patterns 171 may increase the light emitting area of ​​the light generated by the organic light emitting diode OLED.

[0080] Hereinafter, a light emission pattern generated by the light L1 emitted by the organic light emitting diode OLED in the first area TA1 is defined as a first light emission pattern EP1. A light emission pattern generated by the light L2a, L2b, and L2c having passed through the diffraction grating layer 170 in the second area TA2 is defined as a second light emission pattern EP2. The first area TA1 may be any area arranged below the filling layer 230. The second area TA2 may be an area arranged above the diffraction grating layer 170. In addition, the light L1 emitted from the organic light emitting diode OLED is referred to as "emitted light", and the light L2a, L2b, and L2c having passed through the diffraction grating layer 170 are referred to as "diffracted light".

[0081] The emission light L1 may pass through the filling layer 230 and the first cover layer 220 disposed above the encapsulation layer 160, and then be provided to the diffraction grating layer 170. According to the refractive indexes of the filling layer 230 and the first cover layer 220, the emission light L1 may be incident on the filling layer 230 at a first incident angle θ1, and may be incident on the first cover layer 220 at a second incident angle θ2.

[0082] The diffraction grating layer 170 may generate diffracted lights L2a, L2b, and L2c by diffracting the emission light L1. Hereinafter, for convenience of description, a description is provided about the first, second, and third diffracted lights L2a, L2b, and L2c.

[0083] The first, second and third diffracted lights L2a, L2b and L2c may include 0th order diffracted light and 1st order diffracted light, respectively. Here, the 0th order diffracted light refers to light having the same optical path before and after the light is diffracted by the diffraction grating layer 170. In addition, the 1st order diffracted light refers to light having an optical path changed by the diffraction grating layer 170 and having a second diffraction angle relative to the 0th order diffracted light.

[0084] That is, reference numerals L2b1, L2a1, and L2c1 represent 0th-order diffracted light. In addition, reference numerals L2b2, L2b3, L2a2, L2a3, L2c2, and L2c3 represent 1st-order diffracted light. As another embodiment, the first to third diffracted lights L2a, L2b, and L2c may further include 2nd or higher-order diffracted light. However, in the present specification, for ease of description, the first, second, and third diffracted lights L2a, L2b, and L2c including 0th-order diffracted light and 1st-order diffracted light are described as examples.

[0085] The first, second and third diffracted lights L2a, L2b and L2c may include first, second and third effective lights L2a1, L2b3 and L2c2 having optical paths in a direction perpendicular to the display substrate 110, respectively. Here, the vertical direction may include not only a direction completely perpendicular to the display substrate 110, but also a direction substantially close to perpendicular to the display substrate 110. When the optical path of the effective light is in a direction perpendicular to the display substrate 110, the order of the diffracted light is not limited. That is, when the optical path of the effective light is in the vertical direction, the effective light may include both the 0th order diffracted light and the 1st order diffracted light.

[0086] The diffraction grating layer 170 may generate first, second and third effective lights L2a1, L2b3 and L2c2 by diffracting the light L1 emitted by the organic light emitting diode OLED. Therefore, the second light emission pattern EP2 may include a reference light emission pattern Pref and a plurality of replicated light emission patterns P1 to P8 replicated from the reference light emission pattern Pref.

[0087] The size of the first area TA1 may be the same as the size of the second area TA2. On the other hand, the number of light emission patterns included in the second area TA2 is greater than the number of light emission patterns included in the first area TA1. This indicates that the light emission area of ​​the second area TA2 is greater than the light emission area of ​​the first area TA1. A larger light emission area can be expressed as a larger effective light emission area ratio. The effective light emission area ratio is defined as the ratio of the size of the light emission pattern area present in a region to the size of the region. Here, the light emission pattern used to calculate the effective light emission area ratio may include both a reference light emission pattern and a replica light emission pattern. As an example, there are 9 light emission patterns (including a reference light emission pattern Pref and a plurality of replica light emission patterns P1 to P8) in the second area TA2, while there is one light emission pattern in the first area TA1. Therefore, the effective light emission area ratio of the second area TA2 is greater than the effective light emission area ratio of the first area TA1.

[0088] When the diffraction distance β increases, the effective light emission area increases than usual. The diffraction distance β may be affected by the wavelength of the light emitted by the organic light emitting diode OLED, the thickness and refractive index of the filling layer 230, the thickness and refractive index of the first covering layer 220, the pitch DP1 of the diffraction pattern 171, etc. The path of the light emitted by the organic light emitting diode OLED may also be affected by the encapsulation layer 160. However, this is insignificant compared to the influence of the first covering layer 220, etc. Therefore, the diffraction distance β may be expressed as the following equation 1.

[0089] [Equation 1]

[0090] β=z1·tanθ1+z2·tanθ2

[0091] Wherein, z1 represents the thickness of the filling layer 230. z2 represents the shortest distance between the filling layer 230 and the plurality of diffraction patterns 171. As described above, θ1 and θ2 represent the incident angles with respect to the filling layer 230 and the first cover layer 220, respectively, and can be expressed as the following equations 2 and 3, respectively.

[0092] [Equation 2]

[0093]

[0094] Wherein, λ represents the wavelength of light emitted by the organic light emitting diode OLED, and n230 represents the refractive index of the filling layer 230 .

[0095] [Equation 3]

[0096]

[0097] Here, n220 represents the refractive index of the first covering layer 220 .

[0098] When θ1 and θ2 are replaced in Equation 1, the diffraction distance β can be expressed as Equation 4.

[0099] [Equation 4]

[0100]

[0101] As an alternative embodiment, when the refractive index of another element (eg, the encapsulation layer 160 ) disposed between the filling layer 230 and the organic light emitting diode OLED is considered, the diffraction distance β may vary according to the refractive index and thickness of the other element.

[0102] As another example, when the thickness of the filling layer 230 is much smaller than the thickness of the first cover layer 220 , Equation 4 shown above may be simply expressed as Equation 5.

[0103] [Equation 5]

[0104]

[0105] That is, according to one embodiment, Figure 1 The display device 100 can control the diffraction distance β by adjusting the color of the light emitted by the organic light emitting diode OLED, the thickness and refractive index of the first cover layer 220, the pitch DP1 of the diffraction pattern 171, etc. By doing so, the diffraction distance β can be optimized. Figure 1 Therefore, in the present disclosure, when Figure 1 When the display device 100 is used in a head-mounted display device, the occurrence of SDE can be prevented even when the image is expanded by the lens.

[0106] Figure 5 The description includes Figure 1 Schematic cross-sectional view of an example of a head mounted display device 100 of the display device 1 .

[0107] See also Figure 5 The head mounted display device 1 may include a lens 12 and a display device 100 providing an image to the lens 12. In addition, the head mounted display device 1 may further include a camera, an infrared sensor, a signal processor, and a frame having an outer shape that can be worn on a user's head.

[0108] The lens 12 may be disposed between the display device 100 and the user to expand an image provided by the display device 100. The lens 12 may include an opaque lens for implementing virtual reality or a transparent lens or a semi-transparent lens for implementing augmented reality.

[0109] As described above, the display device 100 includes the diffraction grating layer 170. Since the diffraction grating layer 170 includes the plurality of diffraction patterns 171 spaced a certain distance from each other, the effective light emission area of ​​the light emitted from the organic light emitting diode OLED, passing through the filling layer 230 and the first cover layer 220 and thus diffracted can be increased. Therefore, even when the lens 12 expands the image displayed by the display device 100, since the user may not easily recognize the non-light emitting area of ​​the display device 100, when the head mounted display device 1 is driven, SDE can be resolved and a high-quality image can be provided.

[0110] Figure 6 and Figure 7 It indicates manufacturing Figure 1 A schematic diagram of a method for displaying an apparatus 100 is provided.

[0111] According to one embodiment, a method of manufacturing a display device 100 may include: forming an organic light emitting diode OLED and an encapsulation layer 160 on a display substrate 110, forming a diffraction grating layer 170 and a first covering layer 220 on a surface of a relative substrate 210, and placing the relative substrate 210 so that the first covering layer 220 faces the display substrate 110, and then attaching the display substrate 110 to the relative substrate 210 using a filling layer 230.

[0112] like Figure 6 As shown, an organic light emitting diode OLED is formed on a display substrate 110, and then an encapsulation layer 160 is formed on the organic light emitting diode OLED to seal the organic light emitting diode OLED. In this case, as described above, the organic light emitting diode OLED is electrically connected to the Figure 2 A thin film transistor TFT may be formed on the display substrate 110 .

[0113] The display substrate 110 may be formed on a first carrier substrate 10 formed of a glass material or the like. As described above, when the display substrate 110 includes Figure 2 The base substrate 101 and Figure 2 When the base substrate 101 is formed of a flexible material, Figure 2 Thin film transistors TFT, organic light emitting diodes OLED, etc. are formed on a thin film transistor Figure 2 When the first carrier substrate 10 is placed on the base substrate 101, the first carrier substrate 10 can Figure 2 The base substrate 101 remains flat.

[0114] Then, if Figure 7 As shown, the diffraction grating layer 170 and the first cover layer 220 are sequentially formed on the surface of the opposite substrate 210. The opposite substrate 210 may be formed on the second carrier substrate 20 formed of a glass material or the like. Therefore, when the opposite substrate 210 is formed of a material such as polyimide, the surface of the opposite substrate 210 may be very flat. In addition, when the diffraction grating layer 170 and the first cover layer 220 are formed on the opposite substrate 210, bending of the opposite substrate 210 may be prevented.

[0115] The diffraction grating layer 170 may include at least one of silicon oxide, silicon nitride, and silicon oxynitride. As an example, the diffraction grating layer 170 may be formed by placing a deposition mask on the surface of the opposing substrate 210 and then depositing the above material. The deposition mask includes a plurality of openings, and a plurality of diffraction patterns 171 of the diffraction grating layer 170 may be formed at the positions of the plurality of diffraction patterns 171. As another example, the material of the diffraction grating layer 170 may be deposited on the entire surface of the opposing substrate 210 to form a layer, and then patterned to form a plurality of diffraction patterns 171.

[0116] Then, a first cover layer 220 is formed on the diffraction grating layer 170. The first cover layer 220 may be formed of an organic material or an inorganic material. When the first cover layer 220 is formed of an organic material, the first cover layer 220 may include acrylic, Alq 3 At least one of CuPc, CBP and α-NPB. The first capping layer 220 may be formed using a method such as slit coating.

[0117] As another example, when the first capping layer 220 is formed of an inorganic material, the first capping layer 220 may include SiO 2 、SiN x 、ZnO 2 、TiO 2 、ZrO 2 , ITO and IZO, and is formed by using a deposition process. Specifically, since the first covering layer 220 is formed separately from the display substrate 110, even when the first covering layer 220 is formed by using a high temperature deposition method rather than a low temperature deposition method, the organic light emitting diode OLED of the display substrate 110 can be prevented from being damaged by heating in the process of forming the first covering layer 220. Therefore, the first covering layer 220 can be made of, for example, TiO 2 、ZrO 2 And other materials.

[0118] Since the diffraction grating layer 170 includes the plurality of diffraction patterns 171 separated from each other, the first cover layer 220 is disposed not only on the plurality of diffraction patterns 171 but also on the surface of the opposing substrate 210 between the plurality of diffraction patterns 171. That is, the plurality of diffraction patterns 171 may have a shape protruding into the first cover layer 220.

[0119] Then, after arranging the opposite substrate 210 so that the first cover layer 220 faces the display substrate 110, the display substrate 110 is attached to the opposite substrate 210, and the filling layer 230 is arranged between the first cover layer 220 and the encapsulation layer 160, and then attached to the opposite substrate 210 and the display substrate 110. The filling layer 230 may be sprayed onto a surface of at least one of the encapsulation layer 160 and the first cover layer 220. The filling layer 230 may be PSA, OCA, etc., and have a thickness of about 10 μm or less.

[0120] After the counter substrate 210 is attached to the display substrate 110, the first carrier substrate 10 is separated from the display substrate 110, and then the second carrier substrate 20 is separated from the counter substrate 210. As an example, the first carrier substrate 10 is separated from the display substrate 110. Figure 2The first carrier substrate 10 is separated from the display substrate 110 by irradiating laser between the base substrate 101 and the first carrier substrate 10. Similarly, the second carrier substrate 20 is separated from the opposite substrate 210 by irradiating laser between the opposite substrate 210 and the second carrier substrate 20.

[0121] Figure 8 is a schematic cross-sectional view illustrating an example of a display device 100B according to another embodiment.

[0122] Figure 8 The display device 100B may include a display substrate 110, an organic light-emitting device OLED disposed on the display substrate 110, an encapsulation layer 160 disposed on the organic light-emitting device OLED, a second covering layer 224 disposed on the encapsulation layer 160, a filling layer 230 disposed on the second covering layer 224, a first covering layer 222 disposed on the filling layer 230, a diffraction grating layer 170 disposed on the first covering layer 222, and an opposite substrate 210 disposed on the diffraction grating layer 170. That is, Figure 1 Compared with the display device 100, Figure 8 The display device 100B further includes a second covering layer 224 between the encapsulation layer 160 and the filling layer 230 .

[0123] Since the display substrate 110, the organic light emitting diode OLED, the encapsulation layer 160, the filling layer 230 and the opposite substrate 210 are referenced Figures 1 to 4 is shown and described, so a description thereof is not provided here.

[0124] The first cover layer 222 and the second cover layer 224 separate the organic light emitting diode OLED from the diffraction grating layer 170 by a certain distance. By adjusting the thickness of the first cover layer 222 and the second cover layer 224, when the light emitting area of ​​the light generated by the organic light emitting diode OLED is expanded, blurring can be prevented from occurring. As an example, the thickness of the first cover layer 222 may be the same as the thickness of the second cover layer 224, and the filling layer 230 may be arranged between the first cover layer 222 and the second cover layer 224. Therefore, compared with when the first cover layer 222 and the second cover layer 224 are continuously arranged on one side of the filling layer 230, the stress applied to the display substrate 110 or the opposite substrate 210 is reduced, thereby preventing or minimizing the bending of the display substrate 110 or the opposite substrate 210. As another example, the thickness of the second cover layer 224 may be greater than the thickness of the first cover layer 222. Therefore, the stress applied to the opposite substrate 210 having a relatively small thickness compared to the thickness of the display substrate 110 is further reduced, thereby effectively preventing the bending of the opposite substrate 210, etc.

[0125] The first cover layer 222 and the second cover layer 224 may be formed of an inorganic material or an organic material.

[0126] When the first cover layer 222 and the second cover layer 224 are formed of an inorganic material, the first cover layer 222 and the second cover layer 224 may include SiO 2 、SiN x 、ZnO 2 、TiO 2 、ZrO 2 , ITO and IZO. In addition, when the first cover layer 222 and the second cover layer 224 are formed of organic materials, the first cover layer 222 and

[0127] The second covering layer 224 may include acrylic, Alq 3 , CuPc, CBP and α-NPB. The first cover layer 222 may include the same material as the second cover layer 224. Therefore, when the overall thickness of the first cover layer 222 and the second cover layer 224 is Figure 1 When the thickness of the first cover layer 220 is the same or similar to that of the first cover layer 220, the diffraction distance caused by the second cover layer 224 and the first cover layer 222 can be the same as that of the reference Figure 1 The diffraction distances in the described cases remain the same or similar.

[0128] Fig. 9 and 10 It indicates manufacturing Figure 8 Schematic cross-sectional view of a method for manufacturing a display device 100B.

[0129] According to one embodiment, a method of manufacturing a display device 100B may include: forming an organic light emitting diode OLED and an encapsulation layer 160 on a display substrate 110, forming a second covering layer 224 on the encapsulation layer 160, forming a diffraction grating layer 170 and a first covering layer 222 on a surface of a relative substrate 210, and attaching the display substrate 110 to the relative substrate 210 using a filling layer 230.

[0130] like Fig. 9 As shown, an organic light emitting diode OLED is formed on a display substrate 110, and then an encapsulation layer 160 is formed on the organic light emitting diode OLED to seal the organic light emitting diode OLED. As described above, a substrate electrically connected to the organic light emitting diode OLED may be formed on the display substrate 110. Figure 2 In addition, a second covering layer 224 may be further formed on the encapsulation layer 160. The second covering layer 224 may include Figure 1 The material of the first cover layer 220 is the same material.

[0131] The display substrate 110 may be formed on a first carrier substrate 10 formed of a glass material or the like. Figure 2 When the base substrate 101 is formed of a flexible material, Figure 2 The thin film transistor TFT, the organic light emitting diode OLED, the encapsulation layer 160 and the second covering layer 224 are formed on a thin film transistor TFT, an organic light emitting diode OLED, a sealing layer 160 and a second covering layer 224. Figure 2 When the base substrate 101 is formed on the Figure 2 The base substrate 101 can be kept flat.

[0132] Then, if Fig.10 As shown, the diffraction grating layer 170 and the first cover layer 222 are continuously formed on the surface of the opposite substrate 210 .

[0133] As an example, the opposite substrate 210 may be formed of polyimide on the second carrier substrate 20 formed of a glass material, etc. Therefore, when the diffraction grating layer 170 and the first cover layer 222 are formed on the opposite substrate 210, bending of the opposite substrate 210 may be prevented.

[0134] The diffraction grating layer 170 may include at least one of silicon oxide, silicon nitride, and silicon oxynitride. As an example, the diffraction grating layer 170 may be formed by placing a deposition mask on the surface of the opposing substrate 210 and then depositing the above material. The deposition mask includes a plurality of openings, and a plurality of diffraction patterns 171 of the diffraction grating layer 170 may be formed at the positions of the plurality of openings. As another example, the material of the diffraction grating layer 170 may be deposited on the surface of the opposing substrate 210 to form a layer, and then patterned to form a plurality of diffraction patterns 171.

[0135] The first cover layer 222 is formed to cover the plurality of diffraction patterns 171. Therefore, the first cover layer 222 is arranged not only on the plurality of diffraction patterns 171 but also on the surface of the opposing substrate 210 between the diffraction patterns 171. That is, the plurality of diffraction patterns 171 may have a shape protruding into the first cover layer 222.

[0136] The first cover layer 222 may be formed of the same material as the second cover layer 224. The first cover layer 222 and the second cover layer 224 separate the organic light emitting diode OLED from the diffraction grating layer 170 by a certain distance. By adjusting the thickness of the first cover layer 222 and the second cover layer 224, when the light emission area of ​​the light generated by the organic light emitting diode OLED is expanded, blurring may be prevented from occurring. Therefore, when the first cover layer 222 may include the same material as the second cover layer 224, and the overall thickness of the first cover layer 222 and the second cover layer 224 is the same as the thickness of the second cover layer 224, the organic light emitting diode OLED may be formed of the same material as the second cover layer 224. Figure 1When the thickness of the first cover layer 220 is the same or similar to that of the first cover layer 220, the diffraction distance caused by the second cover layer 224 and the first cover layer 222 can be the same as that of the reference Figure 1 The diffraction distances in the described cases remain the same or similar.

[0137] As an example, the thickness of the first cover layer 222 may be the same as the thickness of the second cover layer 224. Therefore, compared with when the first cover layer 222 and the second cover layer 224 are continuously formed on one side of the filling layer 230, the stress applied to the display substrate 110 or the opposite substrate 210 is reduced, thereby preventing or minimizing the bending of the display substrate 110 or the opposite substrate 210. As another example, the thickness of the first cover layer 222 may be less than the thickness of the second cover layer 224. Therefore, the stress applied to the opposite substrate 210 having a relatively small thickness compared with the thickness of the display substrate 110 is further reduced, thereby effectively preventing the bending of the opposite substrate 210, etc.

[0138] Then, after disposing the filling layer 230 between the display substrate 110 and the opposite substrate 210, the first cover layer 222 is attached to the second cover layer 224. The filling layer 230 may be PSA, OCA, etc., and have a thickness of about 10 μm or less.

[0139] After the first cover layer 222 is attached to the second cover layer 224, the first carrier substrate 10 is separated from the display substrate 110, and then the second carrier substrate 20 is separated from the opposite substrate 210. As an example, the first cover layer 222 may be attached to the second cover layer 224. Figure 2 The first carrier substrate 10 is separated from the display substrate 110 by irradiating laser between the base substrate 101 and the first carrier substrate 10. Similarly, the second carrier substrate 20 is separated from the opposite substrate 210 by irradiating laser between the opposite substrate 210 and the second carrier substrate 20.

[0140] According to the present disclosure, since the diffraction grating layer increases the light emitting area by diffracting the light generated by the display device, the display device can resolve SDE and provide high-quality images when the head-mounted display device is driven. However, the scope of the present disclosure is not limited by this effect.

[0141] It should be understood that the embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects in each embodiment should typically be considered as available for other similar features or aspects in other embodiments.

[0142] Although one or more embodiments have been described with reference to the drawings, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the claims.

Claims

1. A display device, comprising: Display substrate; A light emitting device on the display substrate; An encapsulation layer disposed above the display substrate and encapsulating the light-emitting device; A filling layer on the encapsulation layer; a first covering layer formed of a material different from the filling layer and disposed on the filling layer; an opposing substrate on the first cover layer; as well as a diffraction grating layer between the first cover layer and the opposite substrate, Wherein, the diffraction grating layer includes a plurality of diffraction patterns spaced a certain distance from each other, wherein the plurality of diffraction patterns protrude from a surface of the opposing substrate in a direction perpendicular to the opposing substrate, and the surface of the opposing substrate faces the display substrate, and Wherein, the thickness of the filling layer is smaller than the thickness of the first covering layer.

2. The display device according to claim 1, further comprising: A second covering layer is between the encapsulation layer and the filling layer. The display device according to claim 2 , wherein a thickness of the second covering layer is greater than a thickness of the first covering layer. The display device according to claim 2 , wherein the first cover layer comprises the same material as that of the second cover layer. 5 . The display device according to claim 1 , wherein the plurality of diffraction patterns are arranged at the same interval in a first direction and a second direction that perpendicularly intersect each other. 6 . The display device according to claim 1 , wherein the encapsulation layer comprises a first inorganic encapsulation layer, an organic encapsulation layer, and a second inorganic encapsulation layer stacked in sequence. 7 . The display device according to claim 1 , wherein the light generated by the light emitting device passes through the diffraction grating layer to expand a light emitting area.

8. The display device according to claim 1, wherein the display substrate comprises a base substrate and a thin film transistor, the thin film transistor being arranged over the base substrate and electrically connected to the light emitting device, and The light emitting device is an organic light emitting diode having a pixel electrode electrically connected to the thin film transistor, an opposite electrode above the pixel electrode, and an intermediate layer between the pixel electrode and the opposite electrode and including an emission layer. 9 . The display device according to claim 8 , wherein the base substrate and the opposite substrate each include polyimide. 10 . The display device according to claim 1 , wherein the plurality of diffraction patterns diffract the light generated by the light emitting device to generate a reference light emission pattern and a plurality of replica light emission patterns.

11. A method for manufacturing a display device, the method comprising: forming a light emitting device on a display substrate; forming an encapsulation layer on the display substrate to encapsulate the light-emitting device; forming a diffraction grating layer on a surface of the opposing substrate; forming a first covering layer on the diffraction grating layer; and arranging the opposing substrate so that the diffraction grating layer faces the display substrate, and then attaching the opposing substrate to the display substrate using a filling layer, wherein the diffraction grating layer protrudes from the surface of the opposing substrate in a direction perpendicular to the opposing substrate and includes a plurality of diffraction patterns spaced apart from each other, wherein the first covering layer is formed of a material different from that of the filling layer and is disposed on the plurality of diffraction patterns and on the surface of the opposing substrate between the plurality of diffraction patterns, and Wherein, the thickness of the filling layer is smaller than the thickness of the first covering layer. 12 . The method according to claim 11 , wherein the plurality of diffraction patterns are arranged at the same interval in a first direction and a second direction that are perpendicular to each other.

13. The method according to claim 11, further comprising: Before attaching the opposite substrate to the display substrate, a second cover layer is formed on the encapsulation layer. The method according to claim 13 , wherein a thickness of the second cover layer is greater than a thickness of the first cover layer. The method of claim 13 , wherein the first cover layer comprises a same material as that of the second cover layer.

16. The method according to claim 11, wherein the display substrate comprises a base substrate and a thin film transistor, the thin film transistor being arranged over the base substrate and electrically connected to the light emitting device, and The base substrate is formed on a first carrier substrate, and After the opposing substrate is attached to the display substrate, the first carrier substrate is separated from the base substrate.

17. The method according to claim 16, wherein the light-emitting device is an organic light-emitting diode having a pixel electrode electrically connected to the thin film transistor, a relative electrode above the pixel electrode, and an intermediate layer between the pixel electrode and the relative electrode and including an emission layer.

18. The method according to claim 16, wherein the opposing substrate is formed on a second carrier substrate, and After the opposing substrate is attached to the display substrate, the second carrier substrate is separated from the opposing substrate.

19. The method of claim 18, wherein the base substrate and the opposing substrate each comprise polyimide. 20 . The method according to claim 11 , wherein the encapsulation layer is formed by sequentially stacking a first inorganic encapsulation layer, an organic encapsulation layer, and a second inorganic encapsulation layer.

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