Display apparatus and method of manufacturing same

Abstract

The invention relates to a display device and a method of manufacturing the same. The display apparatus includes a substrate, an organic light emitting device disposed over the substrate, a first inorganic encapsulation layer covering the organic light emitting device, an organic encapsulation layer on the first inorganic encapsulation layer, a second inorganic encapsulation layer on the organic encapsulation layer, and a third inorganic encapsulation layer on the second inorganic encapsulation layer, wherein the third inorganic encapsulation layer is thicker than the second inorganic encapsulation layer, and the second inorganic encapsulation layer has a thickness of about # imgabs 0 # to about # imgabs 1 #.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims the benefit of priority from Korean Patent Application No. 10-2023-0100700 filed in the Korean Intellectual Property Office on August 1, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] One or more embodiments relate to a display device and a method of manufacturing the display device, and more particularly, to a display device and a method of manufacturing the display device having a low defect occurrence rate during a manufacturing process. Background Art

[0004] Generally speaking, a display device includes a pixel circuit that controls whether each pixel emits light and the degree of light emission, and a display device electrically connected to the pixel circuit. In addition, in order to protect the display device from external impurities, the display device may include an encapsulation layer covering the display area. Summary of the invention

[0005] However, in existing display devices, the display device may be damaged due to outgassing generated from an organic encapsulation layer during a manufacturing process, resulting in a defective display device.

[0006] One or more embodiments include a display device having a low defect occurrence rate during a manufacturing process and a method of manufacturing the display device.The embodiments set forth herein are examples, and the scope of the present disclosure is not limited thereto.

[0007] 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 of the disclosure.

[0008] According to one or more embodiments, a display device includes a substrate, an organic light-emitting device disposed on the substrate, a first inorganic encapsulation layer covering the organic light-emitting device, an organic encapsulation layer on the first inorganic encapsulation layer, a second inorganic encapsulation layer on the organic encapsulation layer, and a third inorganic encapsulation layer on the second inorganic encapsulation layer, wherein the third inorganic encapsulation layer is thicker than the second inorganic encapsulation layer, and the second inorganic encapsulation layer has a thickness of about 100 nm. to about Thickness.

[0009] The sum of the thickness of the second inorganic encapsulating layer and the thickness of the third inorganic encapsulating layer may be about to about

[0010] The second inorganic encapsulation layer may have a thickness of about to about Thickness.

[0011] The second inorganic encapsulation layer may have a thickness of about to about Thickness.

[0012] The first inorganic encapsulating layer may include silicon oxynitride, the second inorganic encapsulating layer may include silicon oxynitride, and the third inorganic encapsulating layer may include silicon nitride.

[0013] An average content of oxygen atoms in the entire second inorganic encapsulating layer may be about 5.0 atomic percent (at %) to about 7.0 atomic percent (at %).

[0014] The refractive index of the second inorganic encapsulating layer may be about 1.86 to about 1.89.

[0015] The refractive index of the third inorganic encapsulating layer may be greater than the refractive index of the second inorganic encapsulating layer.

[0016] An average content of oxygen atoms in the entire first inorganic encapsulating layer may be higher than an average content of oxygen atoms in the entire second inorganic encapsulating layer.

[0017] The first inorganic encapsulation layer may include a first-first inorganic encapsulation layer covering the organic light-emitting device and including silicon oxynitride, and a first-second inorganic encapsulation layer disposed on the first-first inorganic encapsulation layer and including silicon oxynitride, wherein an average content of oxygen atoms in the entire first-second inorganic encapsulation layer may be higher than an average content of oxygen atoms in the entire first-first inorganic encapsulation layer.

[0018] The first-second inorganic encapsulating layer may be thinner than the first-first inorganic encapsulating layer.

[0019] According to one or more embodiments, a method of manufacturing a display device includes forming an organic light-emitting device on a substrate, forming a first inorganic encapsulation layer covering the organic light-emitting device, forming an organic encapsulation layer on the first inorganic encapsulation layer, and forming a first inorganic encapsulation layer having a thickness of about 100 nm on the organic encapsulation layer. to about A second inorganic encapsulating layer having a thickness of , and a third inorganic encapsulating layer is formed on the second inorganic encapsulating layer, the third inorganic encapsulating layer being thicker than the second inorganic encapsulating layer.

[0020] The method may further include surface-treating an upper surface of the organic encapsulating layer by using plasma between the forming of the organic encapsulating layer and the forming of the second inorganic encapsulating layer.

[0021] The forming of the third inorganic encapsulating layer may include forming the third inorganic encapsulating layer so that a sum of a thickness of the second inorganic encapsulating layer and a thickness of the third inorganic encapsulating layer is about to about

[0022] The forming of the second inorganic encapsulation layer may include forming the second inorganic encapsulation layer to about to about Thickness.

[0023] The forming of the second inorganic encapsulation layer may include forming the second inorganic encapsulation layer to about to about Thickness.

[0024] Forming the first inorganic encapsulating layer may include forming an inorganic encapsulating layer including silicon oxynitride, forming the second inorganic encapsulating layer may include forming an inorganic encapsulating layer using a reaction gas not including an oxygen source, and forming the third inorganic encapsulating layer may include forming an inorganic encapsulating layer including silicon nitride.

[0025] An average content of oxygen atoms in the entire second inorganic encapsulating layer may be about 5.0 atomic percent (at %) to about 7.0 atomic percent (at %).

[0026] The refractive index of the second inorganic encapsulating layer may be about 1.86 to about 1.89.

[0027] The refractive index of the third inorganic encapsulating layer may be greater than the refractive index of the second inorganic encapsulating layer.

[0028] An average content of oxygen atoms in the entire first inorganic encapsulating layer may be higher than an average content of oxygen atoms in the entire second inorganic encapsulating layer.

[0029] The formation of the first inorganic encapsulation layer may include forming a first-first inorganic encapsulation layer including silicon oxynitride to cover the organic light-emitting device, and forming a first-second inorganic encapsulation layer including silicon oxynitride on the first-first inorganic encapsulation layer, wherein the average content of oxygen atoms in the entire first-second inorganic encapsulation layer may be higher than the average content of oxygen atoms in the entire first-first inorganic encapsulation layer.

[0030] The first-second inorganic encapsulating layer may be thinner than the first-first inorganic encapsulating layer.

[0031]

[0013] Other aspects, features and advantages in addition to those described above will be apparent from the detailed description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0033] Figure 1 is a schematic cross-sectional view showing a display device according to an embodiment;

[0034] Figure 2 To show Figure 1 A schematic conceptual diagram of a portion of a display device;

[0035] Figure 3 , Figure 4 and Figure 5 To show the manufacturing Figure 1 A schematic cross-sectional view of a process for manufacturing a display device of the present invention; and

[0036] Figure 6 is a schematic cross-sectional view showing a display device according to an embodiment. DETAILED DESCRIPTION

[0037] The embodiments will now be explained in detail with reference to their examples in the accompanying drawings, wherein the same reference numerals refer to the same elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the description set forth herein. Accordingly, the embodiments are described below only by reference to the figures to explain aspects of the present description. As used herein, the term "and / or" includes any and all combinations of one or more related enumerated items. Throughout this disclosure, the expression "at least one of a, b, and c" indicates only a, only b, only c, both a and b, both a and c, both b and c, all a, b, and c, or variations thereof.

[0038] Various modifications may be applied to the embodiments presented, and specific embodiments will be illustrated in the drawings and described in the detailed description section. The effects and features of the embodiments presented and methods of implementing the same will be more clearly understood with reference to the detailed description in conjunction with the drawings below. However, the embodiments presented may be implemented in various forms, and are not limited to the embodiments presented below.

[0039] Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings, and in the description with reference to the drawings, the same or corresponding components are denoted by the same reference numerals and redundant descriptions thereof are omitted.

[0040] It will be understood that when a component (e.g., a layer, a film, a region, or a plate) is referred to as being "on" another component (e.g., a layer, a film, a region, or a plate), the component (e.g., a layer, a film, a region, or a plate) may be directly on the other component (e.g., a layer, a film, a region, or a plate), or there may be an intervening component (e.g., a layer, a film, a region, or a plate) therebetween. For convenience of explanation, the size of the components in the drawings may be exaggerated. For example, because the size and thickness of the components in the drawings are arbitrarily explained for convenience of explanation, the following embodiments are not limited thereto.

[0041] The x-axis, y-axis, and z-axis are not limited to the three axes of the rectangular coordinate system and can be interpreted in a broader sense. For example, the x-axis, y-axis, and z-axis can be perpendicular to each other, or can represent different directions that are not perpendicular to each other.

[0042] In the following embodiments, it will 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 terms are only used to distinguish one component from another component.

[0043] In the following embodiments, it will be further understood that the terms “include,” “comprise,” and / or “have” used herein indicate the presence of stated features or components, but do not preclude the presence or addition of one or more other features or components.

[0044] In the specification, an expression such as "A and / or B" may include A, B, or A and B. In addition, an expression such as "at least one of A and B" may include A, B, or A and B.

[0045] In the following embodiments, when layers, regions, or components are connected to each other, these layers, regions, or components may be directly connected to each other, or another layer, another region, or another component may be inserted between these layers, regions, or components and thus these layers, regions, or components may be indirectly connected to each other. For example, in the following embodiments, when layers, regions, or components are electrically connected to each other, these layers, regions, or components may be directly electrically connected to each other, or another layer, another region, or another component may be inserted between these layers, regions, or components and thus these layers, regions, or components may be indirectly electrically connected to each other.

[0046] Figure 1 1 is a schematic cross-sectional view showing a display device according to an embodiment. The display device according to the present embodiment may include a substrate 100, a thin film transistor 210, an organic light-emitting device 310 as a display device disposed on the substrate 100, and an encapsulation layer 400 covering the organic light-emitting device 310, which are sequentially stacked in the z-axis direction.

[0047] The substrate 100 may include various flexible or bendable materials. For example, the substrate 100 may include a polymer resin (e.g., polyethersulfone (PES), polyacrylate, polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyarylate (PAR), polyimide (PI), polycarbonate (PC) or cellulose acetate propionate (CAP)). However, the substrate 100 may have a multilayer structure including two layers and an isolation layer disposed therebetween, each of the two layers may include a polymer resin, and the isolation layer may include an inorganic material (e.g., silicon oxide, silicon nitride, and silicon oxynitride), and various modifications may be made. In addition, when the substrate 100 is not bent, the substrate 100 may include glass or the like.

[0048] like Figure 1As shown in FIG. 1 , the thin film transistor 210 includes a semiconductor layer 211 (the semiconductor layer 211 includes amorphous silicon, polycrystalline silicon or an organic semiconductor material), a gate electrode 213, a source electrode 215a and a drain electrode 215b. Figure 1 2 shows that the thin film transistor 210 includes a source electrode 215a and a drain electrode 215b, but the present disclosure is not limited thereto. For example, the source electrode 215a and / or the drain electrode 215b may be part of the wiring. Alternatively, the thin film transistor 210 may not have the source electrode 215a and / or the drain electrode 215b, and the source region of the semiconductor layer 211 may be used as the source electrode and / or the drain region of the semiconductor layer 211 may be used as the drain electrode. For example, the source region of the semiconductor layer 211 of the thin film transistor 210 may be integrated into a single body with the drain region of another thin film transistor. In this case, it is understood that the drain electrode of another thin film transistor is electrically connected to the source electrode of the thin film transistor 210.

[0049] In order to ensure insulation between the semiconductor layer 211 and the gate electrode 213, a gate insulating layer 130 including an inorganic material (e.g., silicon oxide, silicon nitride, and / or silicon oxynitride) may be provided between the semiconductor layer 211 and the gate electrode 213. In addition, an interlayer insulating layer 150 including an inorganic material (e.g., silicon oxide, silicon nitride, and / or silicon oxynitride) may be provided on the gate electrode 213, and a source electrode 215a and a drain electrode 215b may be provided on the interlayer insulating layer 150. The insulating layer including the inorganic material may be formed by a chemical vapor deposition (CVD) method or an atomic layer deposition (ALD) method. This also applies to the embodiments described below and modifications thereof.

[0050] A buffer layer 110 including an inorganic material (e.g., silicon oxide, silicon nitride, and / or silicon oxynitride) may be disposed between the thin film transistor 210 and the substrate 100. The buffer layer 110 may increase the smoothness of the upper surface of the substrate 100 or prevent or reduce impurities from the substrate 100 from penetrating into the semiconductor layer 211 of the thin film transistor 210.

[0051] The gate electrode 213 may include a metal (eg, molybdenum or aluminum) and may be formed by a method such as sputtering. The gate electrode 213 may have a single-layer structure or a multi-layer structure. For example, the gate electrode 213 may have a two-layer structure including a molybdenum layer / aluminum layer.

[0052] The source electrode 215a and the drain electrode 215b may include a metal such as titanium or aluminum and may have a single layer or a multi-layer structure. For example, each of the source electrode 215a and the drain electrode 215b may have a triple-layer structure including a titanium layer / aluminum layer / titanium layer.

[0053] The planarization layer 170 may be disposed on the thin film transistor 210. Figure 1As shown in FIG. 1 , when the organic light-emitting device 310 is disposed on the thin film transistor 210, the planarization layer 170 can substantially planarize the upper portion of the thin film transistor 210. The planarization layer 170 may include an organic material (eg, acrylic acid, benzocyclobutene (BCB), or hexamethyldisiloxane (HMDSO)). Figure 1 The planarization layer 170 is shown as a single layer in FIG. 1 , but various modifications may be made. For example, the planarization layer 170 may have a multi-layer structure.

[0054] In the display area of ​​the substrate 100, a display device may be disposed on the planarization layer 170. The display device may be, for example, an organic light emitting device 310 having a pixel electrode 311, an opposing electrode 315, and an intermediate layer 313 disposed therebetween and including an emission layer.

[0055] The organic light-emitting device 310 may be disposed over the substrate 100 , and a pixel circuit electrically connected to the organic light-emitting device 310 and controlling a degree of light emission may be disposed between the substrate 100 and the organic light-emitting device 310 .

[0056] like Figure 1 As shown in FIG. 1 , the pixel electrode 311 is electrically connected to the thin film transistor 210 by contacting the source electrode 215a or the drain electrode 215b through an opening formed in the planarization layer 170. The pixel electrode 311 may include a light-transmitting conductive oxide (eg, indium tin oxide (ITO), In 2 O 3 The pixel electrode 311 may include a light-transmitting conductive layer including an ITO layer / an Ag layer / an ITO layer and a reflective layer including a metal such as Al or Ag. For example, the pixel electrode 311 may have a three-layer structure including an ITO layer / an Ag layer / an ITO layer.

[0057] The pixel defining layer 175 may be disposed on the pixel electrode 311 on the planarization layer 170. The pixel defining layer 175 has an opening corresponding to each sub-pixel, that is, an opening exposing at least a central portion of the pixel electrode 311, and thus serves to define a pixel. Figure 1 In the case shown in FIG. 1 , the pixel defining layer 175 can prevent arcing etc. from occurring at the edge of the pixel electrode 311 by increasing the distance between the edge of the pixel electrode 311 and the counter electrode 315 disposed on the pixel electrode 311. The pixel defining layer 175 may include an organic material such as polyimide or HMDSO.

[0058] The intermediate layer 313 of the organic light-emitting device 310 may include a low molecular weight material or a high molecular weight material. When the intermediate layer 313 includes a low molecular weight material, the intermediate layer 313 may have a structure in which a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), an electron injection layer (EIL), etc. are stacked into a single structure or a composite structure, and may be formed by a vacuum deposition method. When the intermediate layer 313 includes a high molecular weight material, the intermediate layer 313 may have a structure including HTL and EML. In this case, the HTL may include poly (3,4-ethylenedioxythiophene) (PEDOT), and the EML may include a polymer material (e.g., a polyphenylene vinylene (PPV) material or a polyfluorene material). The intermediate layer 313 may be formed by screen printing, inkjet printing, laser induced thermal imaging (LITI), etc.

[0059] However, the intermediate layer 313 is not necessarily limited thereto and may have various structures. In addition, each of the layers of the intermediate layer 313 other than the EML may be integrally formed as a single body over the plurality of pixel electrodes 311. The EML may be formed to correspond to each of the plurality of pixel electrodes 311.

[0060] The counter electrode 315 is disposed on the display area and may be arranged to cover the display area. That is, in terms of the plurality of organic light-emitting devices 310, the counter electrode 315 may be integrally formed as a single body and may overlap with the plurality of pixel electrodes 311 in a plan view. The counter electrode 315 may include a substrate including ITO, In 2 O 3 The counter electrode 315 may include a light-transmitting conductive layer of MgO or IZO, and may also include a semi-transmitting layer including a metal such as Al or Ag. For example, the counter electrode 315 may include a semi-transmitting layer including MgAg.

[0061] Since the organic light-emitting device 310 may be easily damaged by moisture or oxygen from the outside, the encapsulation layer 400 may cover the organic light-emitting device 310 to protect the organic light-emitting device 310. The encapsulation layer 400 may cover the display area and may extend to at least a portion of the peripheral area. The encapsulation layer 400 may include a first inorganic encapsulation layer 410, an organic encapsulation layer 420, a second inorganic encapsulation layer 430, and a third inorganic encapsulation layer 440 sequentially disposed on the organic light-emitting device 310.

[0062] The first inorganic encapsulation layer 410 formed by a chemical vapor deposition method may cover the organic light-emitting device 310. The first inorganic encapsulation layer 410 may include silicon oxynitride. The first inorganic encapsulation layer 410 has a lower ability to prevent penetration of moisture or the like than a third inorganic encapsulation layer 440 to be described later, but has a refractive index lower than that of the third inorganic encapsulation layer 440, and therefore, the extraction rate of light emitted from the organic light-emitting device 310 to the outside may be increased.

[0063] The organic encapsulation layer 420 may include a polymer material. Examples of polymer materials may include silicone resins, acrylic resins (e.g., polymethyl methacrylate, polyacrylic acid, etc.), epoxy resins, polyimide, and polyethylene. In the manufacturing process, a monomer for forming the organic encapsulation layer 420 may be placed on the first inorganic encapsulation layer 410, and then ultraviolet rays or the like may be irradiated to the monomer to form a polymer.

[0064] like Figure 1 As shown in FIG. 1 , since the first inorganic encapsulation layer 410 formed by the chemical vapor deposition method has an approximately uniform thickness, the upper surface of the first inorganic encapsulation layer 410 may have an uneven surface corresponding to the contour of the structure disposed below the first inorganic encapsulation layer 410. Therefore, the upper surface of the first inorganic encapsulation layer 410 is uneven. However, the organic encapsulation layer 420 has a substantially flat upper surface, and accordingly, the second inorganic encapsulation layer 430 disposed on the organic encapsulation layer 420 may also have a substantially flat upper surface.

[0065] The second inorganic encapsulation layer 430 is disposed on the organic encapsulation layer 420 and may include silicon oxynitride. The third inorganic encapsulation layer 440 disposed on the second inorganic encapsulation layer 430 may include silicon nitride. The second inorganic encapsulation layer 430 and the third inorganic encapsulation layer 440 may be formed by chemical vapor deposition. However, the process conditions of the chemical vapor deposition method when forming the second inorganic encapsulation layer 430 may be different from the process conditions of the chemical vapor deposition method when forming the third inorganic encapsulation layer 440. This will be described later.

[0066] The third inorganic encapsulation layer 440 including silicon nitride has an excellent ability to prevent moisture from penetrating from the outside. Therefore, moisture from the outside can be effectively prevented from passing through the encapsulation layer 400 and reaching the organic light-emitting device 310.

[0067] Before forming the second inorganic encapsulation layer 430, the upper surface of the organic encapsulation layer 420 may be subjected to plasma treatment. This may be understood as ashing the upper surface of the organic encapsulation layer 420. By surface treatment, i.e., plasma treatment, impurities on the upper surface of the organic encapsulation layer 420 may be removed, and the surface of the organic encapsulation layer 420 may be modified. By modification, the surface of the organic encapsulation layer 420 may be changed from hydrophobic to hydrophilic, and therefore, later when the second inorganic encapsulation layer 430 is formed, the bonding force between the organic encapsulation layer 420 and the second inorganic encapsulation layer 430 may be increased to facilitate the formation of the second inorganic encapsulation layer 430.

[0068] In the process of surface-treating the organic encapsulation layer 420 in this manner, moisture or the like within the organic encapsulation layer 420 may be located on or near the surface of the organic encapsulation layer 420. In addition, since the process temperature is high when the third inorganic encapsulation layer 440 is formed later, moisture in the organic encapsulation layer 420 may be moved to the outside (exhaust) even during the process of forming the third inorganic encapsulation layer 440. In addition, exhaust may be generated from the organic encapsulation layer 420 during a heat treatment process for reliability evaluation after manufacturing the display device.

[0069] As described above, the first inorganic encapsulation layer 410 is formed by a chemical vapor deposition method. When forming the first inorganic encapsulation layer 410, if impurities (e.g., particles) are present on the organic light-emitting device 310, the first inorganic encapsulation layer 410 may not completely cover the particles. In this case, as a result, pinholes corresponding to the positions of the particles may be formed in the first inorganic encapsulation layer 410. Therefore, when exhaust gas is generated in the organic encapsulation layer 420 as described above, the exhaust gas may move to the organic light-emitting device 310 disposed below through the pinholes in the first inorganic encapsulation layer 410, and therefore, defects (e.g., the organic light-emitting device 310 cannot properly emit light) may occur.

[0070] In the case of the display device according to the present embodiment, in order to prevent such a problem from occurring, the thickness t1 of the second inorganic encapsulating layer 430 may be set to about 500 Å. to about The total amount of exhaust gas generated in the organic encapsulation layer 420 is approximately fixed, and the exhaust gas tends to move upward (i.e., toward the second inorganic encapsulation layer 430). Therefore, when the exhaust gas is completely absorbed by the second inorganic encapsulation layer 430, even if there are pinholes in the first inorganic encapsulation layer 410, the exhaust gas can be prevented from affecting the organic light-emitting device 310 below the first inorganic encapsulation layer 410 or the influence of the exhaust gas can be effectively reduced. For this purpose, the thickness t1 of the second inorganic encapsulation layer 430 may be t2. When the thickness t1 of the second inorganic encapsulation layer 430 is less than When the moisture absorption capacity of the second inorganic encapsulating layer 430 is reduced, most of the exhaust gas generated from the organic encapsulating layer 420 during the manufacturing process may not be absorbed into the second inorganic encapsulating layer 430 .

[0071] The sum t3 of the thickness t1 of the second inorganic encapsulation layer 430 and the thickness t2 of the third inorganic encapsulation layer 440 may be fixed. When the sum t3 of the thickness t1 of the second inorganic encapsulation layer 430 and the thickness t2 of the third inorganic encapsulation layer 440 excessively increases, the extraction rate of light emitted from the organic light-emitting device 310 to the outside may be reduced. The sum t3 of the thickness t1 of the second inorganic encapsulation layer 430 and the thickness t2 of the third inorganic encapsulation layer 440 may be set to And consider the approximation The total thickness t3 of the second inorganic encapsulating layer 430 and the thickness t2 of the third inorganic encapsulating layer 440 may be set to be approximately to about

[0072] In this case, the third inorganic encapsulation layer 440 may be thicker than the second inorganic encapsulation layer 430. The third inorganic encapsulation layer 440 is used to prevent impurities (for example, moisture from the outside) from penetrating into the organic light-emitting device 310, and when the third inorganic encapsulation layer 440 is thinner than the second inorganic encapsulation layer 430, this waterproof ability may not be guaranteed. Specifically, the ratio between the thickness t1 of the second inorganic encapsulation layer 430 and the thickness t2 of the third inorganic encapsulation layer 440 may be 1:9 to 3:7. When the thickness t1 of the second inorganic encapsulation layer 430 exceeds 3 / 10 of the sum t3 of the thickness t1 of the second inorganic encapsulation layer 430 and the thickness t2 of the third inorganic encapsulation layer 440, the thickness t2 of the third inorganic encapsulation layer 440 that prevents moisture from penetrating from the outside may be reduced, and thus, the waterproof ability of the encapsulation layer 400 may be reduced. Accordingly, when the sum t3 of the thickness t1 of the second inorganic encapsulation layer 430 and the thickness t2 of the third inorganic encapsulation layer 440 is When the thickness t1 of the second inorganic encapsulation layer 430 is Its Therefore, the thickness t1 of the second inorganic encapsulation layer 430 may be about to about

[0073] As described above, the first inorganic encapsulation layer 410 may include silicon oxynitride, and therefore, the light extraction rate, which is a ratio of light extracted from the organic light-emitting device 310 to the outside, may be above an appropriate level. This also applies to the second inorganic encapsulation layer 430. By ensuring that the refractive index of the second inorganic encapsulation layer 430 is less than or equal to the refractive index of the third inorganic encapsulation layer 440, the light extraction rate, which is a ratio of light extracted from the organic light-emitting device 310 to the outside, may be above an appropriate level. Because the refractive index of the third inorganic encapsulation layer 440 including silicon nitride is approximately 1.89 to approximately 2.00, it is necessary to ensure that the refractive index of the second inorganic encapsulation layer 430 is approximately 1.86 to approximately 1.89. For this purpose, the thickness t1 of the second inorganic encapsulation layer 430 may be set to approximately to about Light with a wavelength of 555 nm can be used to determine the refractive index. This also applies to the embodiments described below and their modifications.

[0074] Through experiments, it is confirmed that when the thickness of the second inorganic encapsulation layer 430 is The moisture absorption amount of the second inorganic encapsulation layer 430 when the thickness of the second inorganic encapsulation layer 430 is There is no significant difference in the moisture absorption amount of the second inorganic encapsulating layer 430 when . Considering this, the thickness t1 of the second inorganic encapsulating layer 430 may be set to As described above, the sum t3 of the thickness t1 of the second inorganic encapsulating layer 430 and the thickness t2 of the third inorganic encapsulating layer 440 may be In this case, the maximum value of the thickness t1 of the second inorganic encapsulation layer 430 may be This corresponds to 3 / 10 of the sum t3 of the thickness t1 of the second inorganic encapsulating layer 430 and the thickness t2 of the third inorganic encapsulating layer 440. Therefore, the thickness t1 of the second inorganic encapsulating layer 430 may be approximately to about

[0075] When the first inorganic encapsulation layer 410 is formed by using a chemical vapor deposition method, a reaction gas (eg, SiH 4 Gas, N 2 O gas and NH 3 Gas) is used to form the first inorganic encapsulation layer 410 including silicon oxynitride. In contrast, when the second inorganic encapsulation layer 430 is formed by using a chemical vapor deposition method, the reaction gas may be, for example, SiCl 4 Gas and NH 3 The reaction gas of the gas is the same as the reaction gas for forming silicon nitride. In this case, the oxygen contained in the exhaust gas from the organic encapsulation layer 420 may be included in the second inorganic encapsulation layer 430, and as a result, the second inorganic encapsulation layer 430 becomes silicon oxynitride instead of silicon nitride. Accordingly, the average content of oxygen atoms in the entire second inorganic encapsulation layer 430 may be less than the average content of oxygen atoms in the entire first inorganic encapsulation layer 410. The average content of oxygen atoms in the entire second inorganic encapsulation layer 430 formed in this way may be from about 5.0 atomic percent (at%) to about 7.0 atomic percent (at%). The average content of oxygen atoms in the layer can be determined by using TEMEDS (transmission electron microscope energy dispersive spectrometer). This also applies to the embodiments described below and their modifications.

[0076] For reference, the oxygen atom content may vary depending on the position in the second inorganic encapsulating layer 430. Therefore, it is desirable to consider the average content of oxygen atoms in the entire second inorganic encapsulating layer 430 rather than the oxygen atom content at a specific position in the second inorganic encapsulating layer 430.

[0077] Figure 2 To show Figure 1 A schematic conceptual diagram of a portion of a display device. Specifically, Figure 2 A portion of the second inorganic encapsulation layer 430 disposed on the organic encapsulation layer 420 is schematically shown. Figure 2As shown in FIG. 4 , a pinhole is formed in the second inorganic encapsulating layer 430 , and the pinhole is formed by oxygen atoms P2 generated from the organic encapsulating layer 420 .

[0078] As described above, when the second inorganic encapsulating layer 430 is formed by using a chemical vapor deposition method, the reaction gas is the same as the reaction gas used to form silicon nitride. In the process of forming the second inorganic encapsulating layer 430, oxygen contained in the exhaust gas from the organic encapsulating layer 420 may be included in the second inorganic encapsulating layer 430 to form nitrogen oxides. Figure 2 As shown in FIG. 4 , the oxygen atoms P2 cause fine pinholes in the second inorganic encapsulating layer 430 , and thus, empty areas are formed between the clusters P1 included in the second inorganic encapsulating layer 430 .

[0079] Therefore, even if exhaust gas is generated from the organic encapsulation layer 420 due to a high temperature process for forming the third inorganic encapsulation layer 440 or a high temperature environment during a heat treatment process of the display device for reliability evaluation later, the exhaust gas may move to the pinholes included in the second inorganic encapsulation layer 430 and be absorbed by the second inorganic encapsulation layer 430. Accordingly, the defect occurrence rate during the process of manufacturing the display device may be significantly reduced.

[0080] The second inorganic encapsulation layer 430 including pinholes may be a porous structure. However, when the porosity of the second inorganic encapsulation layer 430 is too high, the exhaust gas generated in the organic encapsulation layer 420 may not be captured by the second inorganic encapsulation layer 430 and may move back to the organic encapsulation layer 420 and exist in the organic encapsulation layer 420. In this case, at least a portion of the exhaust gas present in the organic encapsulation layer 420 may move to the organic light-emitting device 310, causing defects in the organic light-emitting device 310. Therefore, in consideration of this, the average content of oxygen atoms in the entire second inorganic encapsulation layer 430 may be set to 7.0 atomic percent (at%) or less.

[0081] As described above, the maximum value of the thickness t1 of the second inorganic encapsulation layer 430 may be In this case, the average content of oxygen atoms in the entire second inorganic encapsulating layer 430 may be reduced to 5.0 at %. Therefore, the average content of oxygen atoms in the entire second inorganic encapsulating layer 430 may be about 5.0 at % to about 7.0 at %.

[0082] Figures 3 to 5 To show the manufacturing Figure 1 Schematic cross-sectional view of a process for a display device.

[0083] First, if Figure 3As shown in FIG. 1 , a thin film transistor 210 and an organic light-emitting device 310 electrically connected to the thin film transistor 210 are formed on a substrate 100. The specific configurations of the thin film transistor 210 and the organic light-emitting device 310 are the same as those described above.

[0084] Next, if Figure 4 As shown in FIG, a first inorganic encapsulation layer 410 including silicon oxynitride covering the organic light-emitting device 310 is formed using a chemical vapor deposition method, and an organic encapsulation layer 420 including an organic material is formed on the first inorganic encapsulation layer 410. Forming the organic encapsulation layer 420 may include forming a monomer layer for the organic encapsulation layer 420 on the first inorganic encapsulation layer 410, and then converting the monomer layer into a polymer layer by, for example, irradiating ultraviolet rays to the monomer layer. The upper surface of the organic encapsulation layer 420 may be substantially flat.

[0085] Afterwards, if Figure 5 As shown in FIG. 1 , a second inorganic encapsulation layer 430 is formed on the organic encapsulation layer 420 to about to about Before forming the second inorganic encapsulation layer 430, the upper surface of the organic encapsulation layer 420 may be subjected to plasma treatment. This may be understood as ashing the upper surface of the organic encapsulation layer 420. By surface treatment, i.e., plasma treatment, impurities on the upper surface of the organic encapsulation layer 420 may be removed, and the surface of the organic encapsulation layer 420 may be modified. By modification, the surface of the organic encapsulation layer 420 may be changed from hydrophobic to hydrophilic, and therefore, when the second inorganic encapsulation layer 430 is formed on the modified organic encapsulation layer 420, the bonding force between the organic encapsulation layer 420 and the second inorganic encapsulation layer 430 may be increased to facilitate the formation of the second inorganic encapsulation layer 430.

[0086] The second inorganic encapsulation layer 430 may also be formed using a chemical vapor deposition method, but when the process conditions of the conventional chemical vapor deposition method are retained, the organic encapsulation layer 420 may be damaged. In view of this, when the second inorganic encapsulation layer 430 is formed, a low-power chemical vapor deposition method having a temperature lower than that of the process conditions of the conventional chemical vapor deposition method is used. As described above, the thickness of the second inorganic encapsulation layer 430 may be set to about to about Can be set to approx. to about Or it can be set to about to about

[0087] When the second inorganic encapsulation layer 430 is formed in this manner, the reaction gas may be a reaction gas for forming silicon nitride. In this case, oxygen contained in the exhaust gas from the organic encapsulation layer 420 may be included in the second inorganic encapsulation layer 430, and as a result, the second inorganic encapsulation layer 430 contains silicon oxynitride. Accordingly, the average content of oxygen atoms in the entire second inorganic encapsulation layer 430 may be less than the average content of oxygen atoms in the entire first inorganic encapsulation layer 410. The average content of oxygen atoms in the entire second inorganic encapsulation layer 430 formed in this manner may be from about 5.0 atomic percent (at%) to about 7.0 atomic percent (at%). In addition, the refractive index of the second inorganic encapsulation layer 430 may be from about 1.86 to about 1.89, which may be less than or equal to the refractive index of the third inorganic encapsulation layer 440 formed later.

[0088] After the second inorganic encapsulation layer 430 is formed in this manner, the third inorganic encapsulation layer 440 may be formed on the second inorganic encapsulation layer 430 by using a conventional chemical vapor deposition method. The third inorganic encapsulation layer 440 may include silicon nitride. When the third inorganic encapsulation layer 440 is formed, the sum t3 of the thickness t1 of the second inorganic encapsulation layer 430 and the thickness t2 of the third inorganic encapsulation layer 440 may be set to about to about

[0089] Heretofore, the case where the first inorganic encapsulation layer 410 is a single layer has been described, but the present disclosure is not limited thereto. Figure 6 As shown in FIG. 1 , the first inorganic encapsulation layer 410 (see FIG. Figure 5 ) may include a first-first inorganic encapsulation layer 411 and a first-second inorganic encapsulation layer 412.

[0090] The first-first inorganic encapsulation layer 411 formed by a chemical vapor deposition method may cover the organic light-emitting device 310. The first-first inorganic encapsulation layer 411 may include silicon oxynitride. The first-first inorganic encapsulation layer 411 has a lower ability to prevent penetration of moisture or the like than the third inorganic encapsulation layer 440, but has a lower refractive index than the third inorganic encapsulation layer 440, and therefore, the extraction rate of light emitted from the organic light-emitting device 310 to the outside may be increased.

[0091] The first-second inorganic encapsulation layer 412 may also be formed by chemical vapor deposition and may be disposed on the first-first inorganic encapsulation layer 411. Similar to the first-first inorganic encapsulation layer 411, the first-second inorganic encapsulation layer 412 may also include silicon oxynitride, but the average content of oxygen atoms in the entire first-second inorganic encapsulation layer 412 may be greater than the average content of oxygen atoms in the entire first-first inorganic encapsulation layer 411. For reference, due to the above reference Figure 1For the same reason described above, the average content of oxygen atoms in the entire second inorganic encapsulating layer 430 may be less than the average content of oxygen atoms in the entire first-first inorganic encapsulating layer 411 .

[0092] The organic encapsulation layer 420 is formed on the first-second inorganic encapsulation layer 412, and therefore, in the process of manufacturing the display device, a monomer for forming the organic encapsulation layer 420 may be placed on the first-second inorganic encapsulation layer 412, and ultraviolet rays or the like may then be irradiated to convert the monomer into a polymer. In this process, when the monomer for forming the organic encapsulation layer 420 is placed on the first-second inorganic encapsulation layer 412, it is necessary to ensure that the monomer for forming the organic encapsulation layer 420 is well dispersed on the first-second inorganic encapsulation layer 412. When the monomer for forming the organic encapsulation layer 420 is not well dispersed, the organic encapsulation layer 420 may not be properly formed at the edge of the display device, or the flatness of the upper surface of the organic encapsulation layer 420 may be reduced. This may be to increase the reflow characteristics of the monomer. For this purpose, it is desirable that the first-second inorganic encapsulation layer 412 has a hydrophilic property, and this may be achieved by increasing the average content of oxygen atoms in the entire first-second inorganic encapsulation layer 412. In other words, it can be considered that the hydrophilicity of the first-second inorganic encapsulating layer 412 is higher than that of the first-first inorganic encapsulating layer 411 .

[0093] For example, in the case of the first-first inorganic encapsulating layer 411, the ratio of the average content of silicon atoms, the average content of oxygen atoms, and the average content of nitrogen atoms in the entire first-first inorganic encapsulating layer 411 may be approximately 46:34:20 (based on atomic percentage (at%)). In the case of the first-second inorganic encapsulating layer 412, the ratio of the average content of silicon atoms, the average content of oxygen atoms, and the average content of nitrogen atoms in the entire first-second inorganic encapsulating layer 412 may be approximately 40:54:6 (based on atomic percentage (at%)). For reference, by using, for example, SiH 4 Gas, N 2 O gas and NH 3 The silicon oxynitride layer is formed by chemical vapor deposition of a gas, and the composition ratio of the silicon oxynitride layer can be adjusted by changing the flow rate of the gas.

[0094] As described above, the first-second inorganic encapsulation layer 412 is intended to allow good dispersion of the monomer used to form the organic encapsulation layer 420, and therefore does not need to be thick. Therefore, the thickness of the first-second inorganic encapsulation layer 412 may be less than the thickness of the first-first inorganic encapsulation layer 411. For example, the thickness of the first-first inorganic encapsulation layer 411 may be approximately 1.1 μm, and the thickness of the first-second inorganic encapsulation layer 412 may be approximately 1.2 μm.

[0095] According to the embodiments of the present disclosure as described above, a display device having a low defect occurrence rate during a manufacturing process and a method of manufacturing the display device can be implemented. However, the scope of the present disclosure is not limited by these effects.

[0096] It should be understood that the embodiments described herein should be considered in a descriptive sense only and not for limiting purposes. The description of features or aspects in each embodiment should generally consider other similar features or aspects that can be used in other embodiments. Although one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made therein without departing from the spirit and scope defined by the appended claims.

Claims

1. A display device, comprising: substrate; an organic light-emitting device disposed on the substrate; A first inorganic encapsulation layer covering the organic light-emitting device; an organic encapsulation layer on the first inorganic encapsulation layer; a second inorganic encapsulation layer on the organic encapsulation layer; and a third inorganic encapsulation layer on the second inorganic encapsulation layer, The third inorganic encapsulation layer is thicker than the second inorganic encapsulation layer, and the second inorganic encapsulation layer has to Thickness.

2. The display device according to claim 1, wherein the sum of the thickness of the second inorganic encapsulation layer and the thickness of the third inorganic encapsulation layer is to 3. The display device according to claim 1, wherein the second inorganic encapsulation layer has to Thickness.

4. The display device according to claim 1, wherein the second inorganic encapsulation layer has to Thickness. 5 . The display device of claim 1 , wherein the first inorganic encapsulating layer comprises silicon oxynitride, the second inorganic encapsulating layer comprises silicon oxynitride, and the third inorganic encapsulating layer comprises silicon nitride. 6 . The display device according to claim 5 , wherein an average content of oxygen atoms in the entire second inorganic encapsulating layer is 5.0 atomic % to 7.0 atomic %. The display device according to claim 5 , wherein a refractive index of the second inorganic encapsulation layer is 1.86 to 1.

89. 8 . The display device of claim 7 , wherein a refractive index of the third inorganic encapsulating layer is greater than the refractive index of the second inorganic encapsulating layer. 9 . The display device according to claim 5 , wherein an average content of oxygen atoms in the entire first inorganic encapsulating layer is higher than an average content of oxygen atoms in the entire second inorganic encapsulating layer.

10. The display device according to claim 1, wherein the first inorganic encapsulation layer comprises: a first-first inorganic encapsulation layer covering the organic light-emitting device and including silicon oxynitride; and a first-second inorganic encapsulating layer disposed on the first-first inorganic encapsulating layer and including silicon oxynitride, The average content of oxygen atoms in the entire first-second inorganic encapsulating layer is higher than the average content of oxygen atoms in the entire first-first inorganic encapsulating layer. 11 . The display device of claim 10 , wherein the first-second inorganic encapsulating layer is thinner than the first-first inorganic encapsulating layer.

12. A method for manufacturing a display device, the method comprising: forming an organic light-emitting device on the substrate; forming a first inorganic encapsulation layer covering the organic light-emitting device; forming an organic encapsulation layer on the first inorganic encapsulation layer; A to A second inorganic encapsulation layer with a thickness of and A third inorganic encapsulating layer is formed on the second inorganic encapsulating layer, the third inorganic encapsulating layer being thicker than the second inorganic encapsulating layer. 13 . The method of claim 12 , further comprising, between the forming of the organic encapsulating layer and the forming of the second inorganic encapsulating layer, surface-treating an upper surface of the organic encapsulating layer by using plasma.

14. The method according to claim 12, wherein the forming of the third inorganic encapsulating layer comprises forming the third inorganic encapsulating layer so that the sum of the thickness of the second inorganic encapsulating layer and the thickness of the third inorganic encapsulating layer is to 15. The method according to claim 12, wherein the forming of the second inorganic encapsulation layer comprises forming the second inorganic encapsulation layer to to Thickness.

16. The method according to claim 12, wherein the forming of the second inorganic encapsulation layer comprises forming the second inorganic encapsulation layer to to Thickness.

17. The method of claim 12, wherein the forming of the first inorganic encapsulation layer comprises forming an inorganic encapsulation layer comprising silicon oxynitride, the forming of the second inorganic encapsulation layer comprises forming an inorganic encapsulation layer using a reaction gas that does not include an oxygen source, and the forming of the third inorganic encapsulation layer comprises forming an inorganic encapsulation layer comprising silicon nitride. 18 . The method according to claim 17 , wherein an average content of oxygen atoms in the entire second inorganic encapsulating layer is 5.0 atomic % to 7.0 atomic %. The method according to claim 17 , wherein the refractive index of the second inorganic encapsulation layer is 1.86 to 1.

89. 20 . The method of claim 19 , wherein a refractive index of the third inorganic encapsulating layer is greater than the refractive index of the second inorganic encapsulating layer. 21 . The method of claim 17 , wherein an average content of oxygen atoms in the entire first inorganic encapsulating layer is higher than an average content of oxygen atoms in the entire second inorganic encapsulating layer.

22. The method according to claim 12, wherein forming the first inorganic encapsulation layer comprises: forming a first-first inorganic encapsulation layer including silicon oxynitride to cover the organic light-emitting device; and forming a first-second inorganic encapsulation layer including silicon oxynitride on the first-first inorganic encapsulation layer, The average content of oxygen atoms in the entire first-second inorganic encapsulating layer is higher than the average content of oxygen atoms in the entire first-first inorganic encapsulating layer. 23 . The method of claim 22 , wherein the first-second inorganic encapsulating layer is thinner than the first-first inorganic encapsulating layer.

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