Display device

Abstract

A display device includes a substrate, a display element on the substrate, a capping layer on the display element, and a thin film encapsulation layer on the capping layer, wherein the capping layer includes a first capping layer on the display element, a second capping layer on the first capping layer, the second capping layer having a refractive index greater than a refractive index of the first capping layer, and a third capping layer on the second capping layer, the third capping layer having a refractive index less than the refractive index of the second capping layer, wherein the second capping layer has a thickness of 30 nanometers (nm) to 60 nm.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefits, and all benefits arising therefrom, to Korean Patent Application No. 10-2020-0057017 filed on May 13, 2020 and Korean Patent Application No. 10-2020-0188554 filed on December 30, 2020, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] Aspects of some exemplary embodiments of this disclosure relate to display devices. Background Technology

[0004] In recent years, the applications of display devices have become more diversified. Furthermore, due to their relatively thinness and light weight, the range of applications for display devices has increased, and research into display devices suitable for use in various fields is ongoing.

[0005] A display element provided in a display device emits light of a predetermined color to display an image, and the emitted light can pass through a sealing member used to seal the display element. In cases where the sealing member has a structure with multiple stacked layers, the light emitted from the display element may be interfered with due to the film thickness of the sealing member.

[0006] The information disclosed in this background section is only intended to enhance the understanding of the background, and therefore, the information discussed in this background section does not necessarily constitute prior art. Summary of the Invention

[0007] Some aspects of exemplary embodiments of this disclosure include a display device capable of reducing the total amount of movement in the color temperature direction by providing a plurality of capping layers having controlled refractive index and thickness between a display element and a sealing member.

[0008] However, the aspects of the embodiments according to this disclosure are not limited to those set forth herein. These and other aspects of the embodiments according to this disclosure will become more apparent to those skilled in the art upon which this disclosure pertains from the following detailed description of the disclosure.

[0009] According to some example embodiments, a display device includes: a substrate; a display element on the substrate; a capping layer on the display element; and a thin-film encapsulation layer on the capping layer, wherein the capping layer includes: a first capping layer on the display element; a second capping layer on the first capping layer, the second capping layer having a refractive index greater than that of the first capping layer; and a third capping layer on the second capping layer, the third capping layer having a refractive index less than that of the second capping layer, wherein the second capping layer has a thickness of 30 nanometers (nm) to 60 nm.

[0010] According to some example embodiments, a display device includes: a substrate; an organic light-emitting diode (OLED) on the substrate; a capping layer on the OLED; and a thin-film encapsulation layer on the capping layer, wherein the capping layer includes: a first capping layer on the OLED; a second capping layer on the first capping layer having a refractive index greater than that of the first capping layer; and a third capping layer on the second capping layer having a refractive index less than that of the second capping layer, wherein the second capping layer has a refractive index in the range of 1.61 to 2.3, and each of the first and third capping layers has a refractive index in the range of 1.45 to 1.6, and wherein the second capping layer has a thickness of 30 nanometers (nm) to 60 nm.

[0011] According to some example embodiments, a display device includes: a substrate; a display element on the substrate; a capping layer on the display element; and a thin-film encapsulation layer on the capping layer, wherein the capping layer includes: a first capping layer on the display element; and a second capping layer between the first capping layer and the thin-film encapsulation layer, wherein the second capping layer is inserted between the first capping layer and the thin-film encapsulation layer, and the second capping layer has a refractive index that is less than that of the first capping layer and greater than that of the thin-film encapsulation layer.

[0012] The display device according to some example embodiments of the present disclosure can reduce the total amount of movement in the color temperature direction by providing a plurality of capping layers having controlled refractive index and thickness between the display element and the sealing member.

[0013] The features of embodiments according to this disclosure are not limited to the foregoing features, and various other features are included in this specification. Attached Figure Description

[0014] The above and other aspects and features of embodiments of the present disclosure will become more apparent from the detailed description of some exemplary embodiments of the present disclosure with reference to the accompanying drawings, wherein:

[0015] Figure 1 This is a schematic diagram illustrating a plan view of a display device according to some example embodiments;

[0016] Figure 2 The figure illustrates a display element arranged in a pixel region of a display device and a pixel circuit connected to the display element, according to some example embodiments.

[0017] Figure 3 This is a cross-sectional view illustrating a portion of a display device according to some example embodiments;

[0018] Figure 4 The diagram illustrates the basis Figure 3 A cross-sectional view of a portion of a modified display device;

[0019] Figure 5 This is a schematic diagram illustrating a display device according to some example embodiments;

[0020] Figure 6 This is a graph showing the minimum perceptible color difference (MPCD) when the thickness of the second capping layer is approximately 23 nm;

[0021] Figure 7 This is a diagram illustrating the minimum perceptible color difference (MPCD) when a second capping layer is applied according to some example embodiments;

[0022] Figure 8 This is a cross-sectional view illustrating a portion of a display device according to some example embodiments;

[0023] Figure 9 This is a schematic diagram illustrating a display device according to some example embodiments;

[0024] Figure 10 The diagram illustrates the basis Figure 8 A cross-sectional view of a portion of a modified display device;

[0025] Figure 11 This is a schematic diagram illustrating a display device according to some example embodiments;

[0026] Figure 12 This is a diagram illustrating the minimum perceptible color difference (MPCD) when a second capping layer is applied according to some example embodiments;

[0027] Figure 13 This is a schematic diagram illustrating a display device according to some example embodiments;

[0028] Figure 14 This is a schematic diagram illustrating a display device according to some example embodiments;

[0029] Figure 15 This is a schematic diagram illustrating a display device according to some embodiments; and

[0030] Figure 16 This is a schematic diagram illustrating a display device according to some embodiments. Detailed Implementation

[0031] Various aspects of some exemplary embodiments of this disclosure may allow for various modifications and have various embodiments, and specific embodiments will be illustrated in the accompanying drawings and described in more detail in the detailed description. The features and characteristics of embodiments according to this disclosure, as well as methods of implementing this disclosure, can be more readily understood by referring to the following detailed description of exemplary embodiments and the accompanying drawings. However, embodiments according to this disclosure are not limited to the exemplary embodiments disclosed below, but can be implemented in various forms.

[0032] In the following description, further details of some exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. In the description with reference to the drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions thereof will be omitted.

[0033] In the example embodiments below, it will be understood that although terms such as “first” and “second” may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another.

[0034] In the following embodiments, the singular forms “a,” “an,” and “the (said)” are intended to include the plural forms unless the context explicitly indicates otherwise.

[0035] When the terms “comprising,” “including,” and “having” are used in the embodiments described below, they specify the presence of stated features, integrals, steps, operations, elements, components, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof.

[0036] In the example embodiments below, it will be understood that when a part such as a membrane, region, or element is referred to as being “on” or “above” another part, it can be directly “on” or “above” another part, or another membrane, region, or element can be inserted between them.

[0037] In the accompanying drawings, the dimensions of the various components may be enlarged or reduced for ease of illustration. For example, since the dimensions and thickness of each element shown in the drawings are arbitrarily illustrated for ease of description, embodiments according to this disclosure are not necessarily limited to those shown.

[0038] When an embodiment can be implemented differently, a particular process can be executed in a different order than that described. For example, two consecutively described processes can be executed substantially simultaneously or in the reverse order of their description.

[0039] In the following example embodiments, when membranes, regions, or components are connected to each other, they can be directly connected to each other, and also indirectly connected to each other when another membrane, another region, or another component is arranged between them. For example, when membranes, regions, or components are electrically connected to each other, they can be directly electrically connected to each other, and also indirectly electrically connected to each other when another membrane, another region, or another component is arranged between them.

[0040] In the example embodiments below, the x-axis, y-axis, and z-axis are not limited to the three axes of a Cartesian coordinate system and can be interpreted in a broad sense that includes the x-axis, y-axis, and z-axis. For example, the x-axis, y-axis, and z-axis can be orthogonal to each other, but can refer to different directions that are not orthogonal to each other.

[0041] In this specification, "A and / or B" means A, B, or A and B.

[0042] Figure 1 This is a schematic map showing a plan view of a display device according to some example embodiments.

[0043] Reference Figure 1 The display device 10 may include a display area DA and a non-display area NDA adjacent to the display area DA. The display device 10 includes a plurality of pixel areas P arranged in the display area DA. A display element capable of emitting light of a color (e.g., a set or predetermined color) is arranged in each pixel area P, and the display element may be connected to a scan line SL and a data line DL. Figure 1 This can be understood as the state of the substrate 100 in the display device 10. For example, it can be understood that the substrate 100 has a display area DA and a non-display area NDA. For example, the planar shape of the display device 10 can be rectangular. The display device 10 can include a short side and a long side. The short side can extend along a first direction (X direction), and the long side can extend along a second direction (Y direction) that intersects the first direction (X direction).

[0044] In the non-display area NDA, a scan driver 1100 that provides scan signals to each pixel area P via scan line SL, a data driver 1200 that provides data signals to the display elements provided in each pixel area P via data line DL, and main power supply wiring for providing a first power supply voltage and a second power supply voltage can be arranged.

[0045] Figure 1The figure shows a data driver 1200 disposed on a substrate 100, but according to some example embodiments, the data driver 1200 may be disposed on a flexible printed circuit board (FPCB) electrically connected to pads disposed on one side of the display device 10.

[0046] The display device 10 according to some example embodiments of the present disclosure may include an organic light-emitting display, an inorganic light-emitting display, or a quantum dot display, etc. Hereinafter, as an example of a display device according to some example embodiments of the present disclosure, an organic light-emitting display will be described; however, the display device according to the embodiments of the present disclosure is not limited thereto, and the features described later can be applied to various types of display devices as described above.

[0047] Figure 2 The figure illustrates a display element arranged in a pixel area of ​​a display device and a pixel circuit connected to the display element, according to some example embodiments.

[0048] Reference Figure 2 An organic light-emitting diode (OLED) serves as the display element and is connected to a pixel circuit PC. The pixel circuit PC may include a first thin-film transistor T1, a second thin-film transistor T2, and a storage capacitor Cst. The OLED may emit, for example, red, green, or blue light, or emit red, green, blue, or white light.

[0049] The second thin-film transistor T2 is a switching thin-film transistor connected to the scan line SL and the data line DL, and can transmit the data voltage input from the data line DL to the first thin-film transistor T1 according to the switching voltage input from the scan line SL. A storage capacitor Cst can be connected to the second thin-film transistor T2 and the drive voltage line PL. The storage capacitor Cst can store a voltage corresponding to the difference between the voltage received from the second thin-film transistor T2 and the first power supply voltage ELVDD supplied to the drive voltage line PL.

[0050] As a driving thin-film transistor, the first thin-film transistor T1 can be connected to the driving voltage line PL and the storage capacitor Cst, and can control the driving current flowing from the driving voltage line PL through the organic light-emitting diode (OLED) in response to the voltage value stored in the storage capacitor Cst. The OLED can emit light with a brightness (e.g., a set or predetermined brightness) through the driving current. The counter electrode (e.g., the cathode) of the OLED can be supplied with a second power supply voltage ELVSS.

[0051] Figure 2The illustration shows a pixel circuit PC comprising two thin-film transistors and a storage capacitor; however, according to some example embodiments, the number of thin-film transistors or the number of storage capacitors can, of course, be modified in various ways depending on the design of the pixel circuit PC.

[0052] Figure 3 This is a cross-sectional view illustrating a portion of a display device according to some example embodiments.

[0053] Reference Figure 3 A pixel circuit layer PCL, including pixel circuits, is disposed on a substrate 100, and an organic light-emitting diode (OLED) serving as a display element is disposed on the pixel circuit layer PCL. The OLED is covered by a thin film encapsulation layer 300.

[0054] The substrate 100 may include a polymer resin. The substrate 100 including the polymer resin may have flexible, rollable, or bendable properties.

[0055] According to some example embodiments, such as Figure 3 As illustrated, substrate 100 may include a first base layer 101, a first barrier layer 102, a second base layer 103, and a second barrier layer 104. Each of the first base layer 101 and the second base layer 103 may include a polymer resin. For example, the first base layer 101 and the second base layer 103 may include polymer resins such as polyethersulfone (PES), polyarylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), polycarbonate (PC), cellulose triacetate (TAC), and cellulose acetate propionate (CAP). The first barrier layer 102 and the second barrier layer 104 are barrier layers that prevent the penetration of foreign matter and may be a single layer or multiple layers comprising inorganic materials such as silicon nitride and silicon oxide.

[0056] Figure 4 The diagram illustrates the basis Figure 3 A cross-sectional view of a portion of a modified display device.

[0057] As an example of modification, such as Figure 4 As illustrated, substrate 100 may be a single layer comprising a glass material. For example, substrate 100 may be a glass substrate with SiO2 as the main component.

[0058] Refer again Figure 3The pixel circuit layer PCL on the substrate 100 described above may include thin-film transistors (TFTs), and although not shown, may include storage capacitors connected to the TFTs. The TFTs may have the same structure for each pixel. Each TFT may be connected to a display element provided in each pixel.

[0059] A thin-film transistor (TFT) may include a semiconductor layer ACT comprising amorphous silicon, polycrystalline silicon, or an organic semiconductor material, a gate electrode GE, a source electrode SE, and a drain electrode DE. To ensure insulation between the semiconductor layer ACT and the gate electrode GE, a gate insulating layer 121 comprising an inorganic material such as silicon oxide, silicon nitride, and / or silicon oxynitride may be inserted between the semiconductor layer ACT and the gate electrode GE. An interlayer insulating layer 131 comprising an inorganic material such as silicon oxide, silicon nitride, and / or silicon oxynitride may be disposed on the gate electrode GE, and the source electrode SE and drain electrode DE may be disposed on the interlayer insulating layer 131 described above. The insulating layer comprising the inorganic material may be formed by chemical vapor deposition (CVD) or atomic layer deposition (ALD).

[0060] The gate electrode GE, source electrode SE, and drain electrode DE can be formed from various conductive materials. The gate electrode GE can include molybdenum or aluminum and can have a single-layer or multi-layer structure. For example, the gate electrode GE can be a single layer of molybdenum, or it can have a three-layer structure including a molybdenum layer, an aluminum layer, and a molybdenum layer. The source electrode SE and drain electrode DE can include titanium or aluminum and can have a single-layer or multi-layer structure. According to some example embodiments, the source electrode SE and drain electrode DE can have a three-layer structure including a titanium layer, an aluminum layer, and a titanium layer.

[0061] A buffer layer 110, comprising inorganic materials such as silicon oxide, silicon nitride, and / or silicon oxynitride, may be inserted between a substrate 100 having the structure described above and a thin-film transistor (TFT). The buffer layer 110 may be used to enhance the smoothness of the upper surface of the substrate 100 or to prevent (or minimize) impurities from penetrating from the substrate 100 into the semiconductor layer ACT of the thin-film transistor TFT.

[0062] The planarization insulating layer 140 can be disposed on the thin-film transistor (TFT). The planarization insulating layer 140 can be formed of an organic material such as acrylic acid, benzocyclobutene (BCB), or hexamethyldisiloxane (HMDSO). Figure 3 In the diagram, the planarized insulating layer 140 is shown as a single layer, but it can be multiple layers.

[0063] Organic light-emitting diodes (OLEDs) include pixel electrodes 221, intermediate layers 222, and counter electrodes 223.

[0064] Pixel electrodes 221 are disposed on a planarization insulating layer 140, and one may be disposed for each pixel. Pixel electrodes 221 may be reflective electrodes. According to some example embodiments, pixel electrodes 221 may include a reflective film comprising silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), or compounds thereof. According to some example embodiments, pixel electrodes 221 may include a transparent or translucent electrode layer disposed above and / or below the reflective film described above. The transparent or translucent electrode layer described above includes at least one selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In2O3), indium gallium oxide (IGO), and aluminum zinc oxide (AZO). In some embodiments, pixel electrodes 221 may have a three-layer structure comprising an ITO layer, an Ag layer, and an ITO layer.

[0065] A pixel defining film 150 is disposed on the pixel electrode 221. The pixel defining film 150 has an opening 150OP exposing the central portion of each pixel electrode 221. The pixel defining film 150 can increase the distance between the edge of the pixel electrode 221 and the counter electrode 223, thereby preventing the generation of electric arcs at the edge of the pixel electrode 221. The pixel defining film 150 is an organic insulating material such as polyimide, polyamide, acrylic resin, benzocyclobutene, hexamethyldisiloxane (HMDSO), and phenolic resin, and can be formed by methods such as spin coating.

[0066] The light-emitting layer 222b can be disposed on the pixel electrode 221 exposed through the opening 150OP of the pixel defining film 150. The light-emitting layer 222b can be an organic material including a fluorescent or phosphorescent material capable of emitting red, green, or red light. The organic material described above can be a low-molecular-weight organic material or a high-molecular-weight organic material.

[0067] The first functional layer 222a and the second functional layer 222c can be disposed below and above the light-emitting layer 222b, respectively. The first functional layer 222a may include, for example, a hole transport layer (HTL) or a hole transport layer and a hole injection layer (HIL). The second functional layer 222c is an element disposed on the light-emitting layer 222b and may include an electron transport layer (ETL) and / or an electron injection layer (EIL). The second functional layer 222c is optional. In some embodiments, the second functional layer 222c may not be provided.

[0068] Although the light-emitting layers 222b are respectively arranged to correspond to the openings of the pixel defining film 150, the first functional layer 222a and the second functional layer 222c may be a common layer, which is integrally formed in the same manner as the counter electrode 223 described later to cover the substrate 100 as a whole, for example, to cover the entire display area of ​​the substrate 100.

[0069] Counter electrode 223 may include a (semi-)transparent layer comprising silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), or alloys thereof. Alternatively, counter electrode 223 may further include a layer such as ITO, IZO, ZnO, or In2O3 on the (semi-)transparent layer comprising the aforementioned materials. According to some example embodiments, counter electrode 223 may include silver (Ag), magnesium (Mg), or an alloy of silver (Ag) and magnesium (Mg).

[0070] A capping layer 230 can be disposed on the counter electrode 223. For example, the capping layer 230 may include LiF, an inorganic insulating material, or an organic insulating material. The capping layer 230 can cover and protect the counter electrode 223 described above from the top.

[0071] The capping layer 230 may include a plurality of stacked films. The plurality of stacked films may include a first capping layer 231 on the counter electrode 223, a second capping layer 233 on the first capping layer 231, and a third capping layer 235 on the second capping layer 233.

[0072] A first capping layer 231 may be disposed between the counter electrode 223 and the second capping layer 233, the second capping layer 233 may be disposed between the first capping layer 231 and the third capping layer 235, and the third capping layer 235 may be disposed between the second capping layer 233 and the thin-film encapsulation layer 300. The first capping layer 231 may be inserted between the counter electrode 223 and the second capping layer 233, the second capping layer 233 may be inserted between the first capping layer 231 and the third capping layer 235, and the third capping layer 235 may be inserted between the second capping layer 233 and the thin-film encapsulation layer 300. As used herein, the term "insertion" means that the corresponding component is in direct contact with the upper and lower components, and that the corresponding component is inserted between the upper and lower components. The first capping layer 231 can contact the counter electrode 223 and the second capping layer 233 respectively. The second capping layer 233 can contact the first capping layer 231 and the third capping layer 235 respectively. The third capping layer 235 can contact the second capping layer 233 and the thin film encapsulation layer 300 respectively.

[0073] For example, capping layer 230 may include an inorganic insulating material. For example, capping layer 230 may include one or more inorganic insulating materials selected from the group consisting of aluminum oxide, titanium oxide, tantalum oxide, hafnium oxide, zinc oxide, silicon oxide, silicon nitride, and silicon oxynitride. The materials of the multiple stacked films of capping layer 230 may differ from each other, but may be the same.

[0074] As described above, a display element provided in a display device emits light of a color (e.g., a set or predetermined color) to provide an image, and the emitted light can pass through a thin-film encapsulation layer 300, which will be described later, to seal the display element. According to some example embodiments, when the thin-film encapsulation layer 300 has a structure with multiple stacked layers, the light emitted from the display element may be interfered with due to the film thickness of the thin-film encapsulation layer 300. The total amount of shift in the color temperature direction at the minimum perceptible chromatic aberration (MPCD) may increase due to the generated interference.

[0075] However, according to some example embodiments, the refractive index and thickness of the multiple stacked films of the capping layer 230 are adjusted so that the total amount of movement in the color temperature direction at the minimum perceptible chromatic difference (MPCD) can be prevented in advance from increasing due to generated interference. A detailed description will be given later.

[0076] The thin-film encapsulation layer 300 can be disposed on the capping layer 230. The thin-film encapsulation layer 300 may include at least one inorganic encapsulation layer and at least one organic encapsulation layer. For example, such as... Figure 4 As illustrated, the thin-film encapsulation layer 300 includes a first inorganic encapsulation layer 310 on the third capping layer 235, an organic encapsulation layer 320 on the first inorganic encapsulation layer 310, and a second inorganic encapsulation layer 330 on the organic encapsulation layer 320, but includes an auxiliary layer 315 inserted between the first inorganic encapsulation layer 310 and the organic encapsulation layer 320.

[0077] The first inorganic encapsulation layer 310 and the second inorganic encapsulation layer 330 may comprise one or more inorganic insulating materials selected from the group consisting of aluminum oxide, titanium oxide, tantalum oxide, hafnium oxide, zinc oxide, silicon oxide, silicon nitride, and silicon oxynitride. In some embodiments, the first inorganic encapsulation layer 310 and the second inorganic encapsulation layer 330 may comprise an inorganic insulating layer containing a nonmetallic element such as silicon oxide, silicon nitride, or silicon oxynitride. The number and type of nonmetallic element included in the first inorganic encapsulation layer 310 may differ from the number and type of nonmetallic element included in the second inorganic encapsulation layer 330. For example, the first inorganic encapsulation layer 310 may comprise silicon oxynitride, and the second inorganic encapsulation layer 330 may comprise silicon nitride, but they are not limited thereto.

[0078] The organic encapsulation layer 320 can alleviate internal stress in the first inorganic encapsulation layer 310 and / or the second inorganic encapsulation layer 330. The organic encapsulation layer 320 may include a polymer-based material. The polymer-based material may include polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polyethylene sulfonate, polyoxymethylene, polyarylate, hexamethyldisiloxane, and acrylic resins (e.g., polymethyl methacrylate or polyacrylic acid, etc.) or any combination thereof.

[0079] The organic encapsulation layer 320 can be formed by applying a monomer with flowability and using a heat- or UV-curable monomer layer. Alternatively, the organic encapsulation layer 320 can be formed by applying the polymer-based material described above.

[0080] An auxiliary layer 315 can be inserted between the first inorganic encapsulation layer 310 and the organic encapsulation layer 320. The auxiliary layer 315 can directly contact the first inorganic encapsulation layer 310 and the organic encapsulation layer 320. For example, the bottom surface of the auxiliary layer 315 can directly contact the top surface of the first inorganic encapsulation layer 310, and the top surface of the auxiliary layer 315 can directly contact the bottom surface of the organic encapsulation layer 320.

[0081] The auxiliary layer 315 may be an inorganic insulating layer containing non-metallic elements. According to some example embodiments, the non-metallic elements contained in the auxiliary layer 315 may be the same non-metallic elements as those in the first inorganic encapsulation layer 310, and the non-metallic elements are, for example, silicon (Si), oxygen (O), and nitrogen (N).

[0082] Light emitted from the organic light-emitting diodes (OLEDs) arranged in each pixel passes through the thin-film encapsulation layer 300 to the outside. At this time, as described above, when viewed from a direction perpendicular to the substrate 100 (e.g., the z-direction) and tilted towards the substrate 100, the total shift in the color temperature direction of the minimum perceptible chromatic aberration (MPCD) due to thin-film interference phenomena in the encapsulation layer 300 may increase. However, according to some example embodiments, the refractive index and thickness of the plurality of stacked films of the capping layer 230 are adjusted such that an increase in the total shift in the color temperature direction of the minimum perceptible chromatic aberration (MPCD) due to the generated interference can be prevented in advance.

[0083] Figure 5 This is a schematic diagram illustrating a display device according to some example embodiments.

[0084] Reference Figure 5 The display device 10 includes a substrate 100, a pixel circuit layer PCL, a display layer 200 including a pixel electrode 221, an intermediate layer 222, a counter electrode 223 and a capping layer 230, and a thin film encapsulation layer 300, which are stacked sequentially.

[0085] The capping layer 230 may include a first capping layer 231, a second capping layer 233, and a third capping layer 235 arranged sequentially along the light propagation direction (or from the display layer 200 toward the thin film encapsulation layer 300).

[0086] The thin-film encapsulation layer 300 may include a first inorganic encapsulation layer 310, an auxiliary layer 315, an organic encapsulation layer 320 disposed on the auxiliary layer 315, and a second inorganic encapsulation layer 330 arranged sequentially along the light propagation direction (or from the display layer 200 toward the thin-film encapsulation layer 300).

[0087] The refractive index of the second capping layer 233 may be greater than that of each of the refractive indices of the first capping layer 231 and the third capping layer 235. For example, the refractive index of the second capping layer 233 may have a value of 1.61 to 2.3. The refractive indices of the first capping layer 231 and the third capping layer 235 may each have a value of 1.45 to 1.6. The refractive indices of the first capping layer 231 and the third capping layer 235 may be the same, but are not limited to this, and the refractive indices of the first capping layer 231 and the third capping layer 235 may be different from each other. For example, the refractive index of the second capping layer 233 may be about 1.97, the refractive index of the first capping layer 231 may be about 1.52, and the refractive index of the third capping layer 235 may be about 1.52, but they are not limited to this.

[0088] The first capping layer 231 may have a first thickness t1. The first thickness t1 may be in the range of about 30 nm to about 40 nm.

[0089] The second capping layer 233 may have a second thickness t2. The second thickness t2 may be in the range of about 30 nm to about 60 nm. According to some example embodiments, the second thickness t2 may be in the range of about 30 nm to about 40 nm. For example, the second thickness t2 may be about 35 nm.

[0090] The third capping layer 235 may have a third thickness t3. The third thickness t3 may be in the range of about 35 nm to about 45 nm.

[0091] According to some example embodiments, as described above, because the refractive index of the second capping layer 233 is greater than that of each of the refractive indices of the first capping layer 231 and the third capping layer 235, and the second thickness t2 of the second capping layer 233 has a range of about 30 nm to about 40 nm, an increase in the total amount of shift in the color temperature direction in the minimum perceptible chromatic aberration (MPCD) due to thin-film interference phenomena of the thin-film encapsulation layer 300 can be prevented in advance when viewed from a direction perpendicular to the substrate 100 (e.g., the z-direction) and a direction tilted to the substrate 100. Furthermore, by making the second thickness t2 of the second capping layer 233 in the range of 60 nm or less, peeling or separation of the second capping layer 233 can be prevented.

[0092] The first inorganic encapsulation layer 310 can be disposed on the third capping layer 235.

[0093] The first inorganic encapsulation layer 310 may have a fourth thickness t4 ranging from about 400 nm to 2200 nm. When the fourth thickness t4 of the first inorganic encapsulation layer 310 is 400 nm or greater, it can prevent moisture penetration, and when the fourth thickness t4 of the first inorganic encapsulation layer 310 is 2200 nm or less, it can prevent the first inorganic encapsulation layer 310 from being peeled off or separated. The thickness of the second inorganic encapsulation layer 330 may be the same as the thickness of the first inorganic encapsulation layer 310, or it may be less than or greater than the thickness of the first inorganic encapsulation layer 310.

[0094] On the other hand, light emitted from the display element passes through the thin film encapsulation layer 300, causing light interference and the like. Although the capping layer 230 described above is designed to prevent an increase in the total amount of shift in the color temperature direction in the minimum perceptible color difference (MPCD) caused by thin film interference phenomena of the thin film encapsulation layer 300 when viewed from a direction perpendicular to the substrate 100 (e.g., the z direction) and a direction tilted to the substrate 100, the change in color coordinates may still be large.

[0095] To address this issue, adjusting the thickness of the first inorganic encapsulation layer 310 could be considered. However, controlling the thickness may be practically difficult due to errors in the equipment used to form the first inorganic encapsulation layer 310 (e.g., CVD equipment). For example, as described above, the first inorganic encapsulation layer 310, which protects the display layer 200 from moisture and other influences, can have a thickness range of approximately 400 nm to 2200 nm to prevent separation of the first inorganic encapsulation layer 310. When the error in the equipment forming the inorganic insulating layer is approximately 10%, the actual deviation in the thickness of the formed first inorganic encapsulation layer 310 corresponds to a range of tens to hundreds of nm. Therefore, it is practically difficult to control the thickness of the first inorganic encapsulation layer 310 to reduce variations in minimum perceptible color difference (MPCD), and there may be limitations in reducing the MPCD variations described above.

[0096] According to some example embodiments, the thin-film encapsulation layer 300 provides an auxiliary layer 315 on the first inorganic encapsulation layer 310, thereby reducing the MPCD variation described above, regardless of the thickness of the first inorganic encapsulation layer 310.

[0097] The auxiliary layer 315 can be formed of an inorganic insulating material, and the fifth thickness t5 of the auxiliary layer 315, used to minimize or prevent variations in the MPCD described above, can be 100 nm or less. For example, the fifth thickness t5 of the auxiliary layer 315 can be from 30 nm to 100 nm. When the fifth thickness t5 of the auxiliary layer 315 is 100 nm or less, control over the fifth thickness t5 of the auxiliary layer 315 can be easily performed.

[0098] The auxiliary layer 315 comprises an inorganic insulating material. As described above, the inorganic insulating material layer formed using a CVD apparatus may have an error of approximately 10% in the actual thickness compared to the target thickness. Because the auxiliary layer 315 can be formed using a CVD apparatus in the same manner as the first inorganic encapsulation layer 310, the actual thickness of the auxiliary layer 315 formed can differ from the target thickness. However, because the auxiliary layer 315 is tens of times smaller than the thickness of the first inorganic encapsulation layer 310, controlling the thickness of the auxiliary layer 315 is much easier, despite the thickness error (e.g., approximately 10%) depending on the CVD apparatus.

[0099] The first inorganic encapsulation layer 310 and the auxiliary layer 315 can have different refractive indices. For example, the refractive index n3 of the auxiliary layer 315 can satisfy the following condition:

[0100] min(n1,n2)+|n2-n1|×0.25 <n3<min(n1,n2)+|n2-n1|×0.75

[0101] Here, n1 represents the refractive index of the first inorganic encapsulation layer, n2 represents the refractive index of the organic encapsulation layer, min(n1,n2) represents the minimum value of n1 and n2, and |n2-n1| represents the absolute value of the difference between n2 and n1.

[0102] When the refractive index n3 of the auxiliary layer 315 is within the range described above, large changes in the MPCD can be minimized or prevented.

[0103] Figure 6 This is a graph illustrating the minimum perceptible color difference (MPCD) when the thickness of the second capping layer is approximately 23 nm. Figure 7 This is a diagram illustrating the minimum perceptible color difference (MPCD) when a second capping layer is applied according to some example embodiments.

[0104] Reference Figure 6 and Figure 7 The MPCD is illustrated as an outline by dividing it into sections (e.g., setting or pre-defined sections), and the MPCD diagram shows that a negative (-) value in the direction away from 0 (zero) relative to the vertical axis (y-axis) indicates that the color turns blue, and a positive (+) value in the direction away from 0 (zero) relative to the vertical axis (y-axis) indicates that the color turns green.

[0105] like Figure 5 As illustrated, when the display device 10 is viewed in a direction perpendicular to the substrate 100 and in a direction tilted to the substrate 100 (e.g., at 0° (z direction) and at tilt angles θ of approximately 30°, 45° and 60° relative to the z direction), the outline of the MPCD is plotted based on the MPCD value.

[0106] It can be seen that, according to such Figure 7 Some example embodiments illustrated herein, and relative to Figure 6 Compared to the described embodiments, the total amount of color temperature in the MPCD of the display device 10 is smaller. For example, according to relative to Figure 6 In the illustrated embodiment, the total change (dx) on the x-axis is approximately 0.038, and the total change (dy) on the y-axis is approximately 0.015, and according to relative to Figure 7 In the illustrated embodiment, the total change (dx) on the x-axis is approximately 0.025, and the total change (dy) on the y-axis is approximately 0.012. That is, according to relative to... Figure 7 The illustrated embodiment, relative to Figure 6 Compared to the illustrated embodiment, the change on the x-axis is 0.013 smaller, and the change on the y-axis is 0.003 smaller.

[0107] Therefore, as from Figure 6 and Figure 7It has been confirmed that, according to some example embodiments, because the refractive index of the second capping layer 233 is greater than that of the first capping layer 231 and the third capping layer 235, and the second thickness t2 of the second capping layer 233 has a range of about 30 nm to about 40 nm, when viewed from a direction perpendicular to the substrate 100 (e.g., the z-direction) and a direction tilted to the substrate 100, an increase in the total amount of shift in the color temperature direction in the minimum perceptible color difference (MPCD) caused by thin film interference phenomena of the thin film encapsulation layer 300 can be prevented.

[0108] In some embodiments, in a display device according to some example embodiments, the thin-film encapsulation layer 300 may include a first inorganic encapsulation layer 310 comprising a plurality of stacked films.

[0109] According to some example embodiments, the first inorganic encapsulation layer 310 may include a plurality of stacked films. For example, the first inorganic encapsulation layer 310 may include a first sub-inorganic encapsulation layer inserted between the third capping layer 235 and the second sub-inorganic encapsulation layer, and a second sub-inorganic encapsulation layer inserted between the first sub-inorganic encapsulation layer and the auxiliary layer 315. In this embodiment, although the first inorganic encapsulation layer 310 is illustrated to include two stacked films in sequence, embodiments according to this disclosure are not limited thereto, and the first inorganic encapsulation layer 310 may include three or more stacked films in sequence.

[0110] The sum of the thicknesses of the first and second inorganic encapsulation layers can be designed to have a reference... Figure 3 and Figure 5 The fourth thickness t4 of the first inorganic encapsulation layer 310 is described as ranging from approximately 400 nm to 2200 nm. The thickness of the first sub-inorganic encapsulation layer may be different from or the same as the thickness of the second sub-inorganic encapsulation layer.

[0111] The refractive indices of the first and second inorganic encapsulation layers can be respectively referenced above. Figure 5 The refractive index of the first inorganic encapsulation layer 310 is selected within a certain range. For example, the refractive indices of the first sub-inorganic encapsulation layer and the second sub-inorganic encapsulation layer may be substantially the same.

[0112] In the following description, a display device according to some example embodiments will be described. According to some example embodiments, the same components as those in the embodiments described above are indicated by the same reference numerals, and their descriptions will be omitted or simplified.

[0113] Figure 8 This is a cross-sectional view illustrating a portion of a display device according to some example embodiments. Figure 9 This is a schematic diagram illustrating a display device according to some example embodiments.

[0114] Reference Figure 8 and Figure 9 The display device may include a substrate 100, a pixel circuit layer PCL, a display layer 200, and a thin-film encapsulation layer 300_1 stacked sequentially, but the thin-film encapsulation layer 300_1 may further include a lower layer 317 disposed below the organic encapsulation layer 320. Apart from the lower layer 317, other components are as referenced. Figure 3 and Figure 5 The elements of the described embodiments are the same, so the following description focuses on the lower layer 317.

[0115] The lower layer 317 can be inserted between the organic encapsulation layer 320 and the auxiliary layer 315. In some embodiments, the refractive index of the lower layer 317 can be between the refractive index of the auxiliary layer 315 and the refractive index of the organic encapsulation layer 320.

[0116] The lower layer 317 may not have the function of a thin-film encapsulation layer, such as moisture permeability. During the process of forming the organic encapsulation layer 320 by applying and curing monomers, the lower layer 317 can control the materials used to form the organic encapsulation layer 320.

[0117] As described above, the lower layer 317 may be a layer without independent optical function and without moisture permeability, and the refractive index of the lower layer 317 may be substantially the same as the refractive index of the organic encapsulation layer 320. The fact that the refractive index of the lower layer 317 is substantially the same as the refractive index of the organic encapsulation layer 320 means that the difference Δn between the refractive indices of the lower layer 317 and the organic encapsulation layer 320 is less than 0.05. For example, the refractive index of the lower layer 317 may be 1.52.

[0118] The thickness of the lower layer 317 can be selected in the range of approximately 50 nm to 100 nm (such as approximately 55 nm to 90 nm or 60 nm to 85 nm). Although the refractive index of the lower layer 317 is substantially the same as that of the organic encapsulation layer 320, an interface can exist between the lower layer 317 and the organic encapsulation layer 320 where they are in contact with each other because the lower layer 317 and the organic encapsulation layer 320 consist of different materials.

[0119] The lower layer 317 may include an inorganic insulating layer. For example, the lower layer 317 may contain non-metallic elements like the first inorganic encapsulation layer 310 and the auxiliary layer 315, or it may contain elements different from the non-metallic elements included in the first inorganic encapsulation layer 310 and the auxiliary layer 315. In some embodiments, the oxygen content of the lower layer 317 may be greater than the oxygen content of the auxiliary layer 315. For example, the lower layer 317 may be an inorganic insulating layer with a relatively high oxygen content, such as an O-rich silicon oxynitride layer.

[0120] For example, the first inorganic encapsulation layer 310, the auxiliary layer 315, and the lower layer 317 may all comprise the same non-metallic elements, such as silicon (Si), oxygen (O), and nitrogen (N). The first silicon oxynitride layer of the first inorganic encapsulation layer 310, the second silicon oxynitride layer of the auxiliary layer 315, and the third silicon oxynitride layer of the lower layer 317 each have different content ratios of silicon (Si), oxygen (O), and nitrogen (N). Therefore, interfaces may exist between the first and second silicon oxynitride layers, and between the second and third silicon oxynitride layers.

[0121] For example, the refractive index n3 of the auxiliary layer 315 can satisfy the following condition:

[0122] min(n1,n2)+|n2-n1|×0.25 <n3<min(n1,n2)+|n2-n1|×0.75

[0123] Here, n1 represents the refractive index of the first inorganic encapsulation layer, n2 represents the refractive index of the lower layer, min(n1,n2) represents the minimum value of n1 and n2, and |n2-n1| represents the absolute value of the difference between n2 and n1.

[0124] Even in this embodiment, since the refractive index of the second capping layer 233 is greater than that of the first capping layer 231 and the third capping layer 235, and the second thickness t2 of the second capping layer 233 has a range of about 30 nm to about 40 nm, when viewed from a direction perpendicular to the substrate 100 (e.g., the z direction) and a direction tilted to the substrate 100, the increase in the total amount of color temperature shift in the minimum perceptible color difference (MPCD) caused by the thin film interference phenomenon of the thin film encapsulation layer 300 can be prevented in advance.

[0125] Figure 10 The diagram illustrates the basis Figure 8 A cross-sectional view of a portion of a modified display device.

[0126] Reference Figure 10 As Figure 8 In a modified example, substrate 100 may be a single layer comprising a glass material. For example, substrate 100 may be a glass substrate with SiO2 as the main component.

[0127] Figure 11 This is a schematic diagram illustrating a display device according to some example embodiments. Figure 12 This is a diagram illustrating the minimum perceptible color difference (MPCD) when a second capping layer is applied according to some example embodiments.

[0128] Figure 11 and Figure 12The second thickness t2 of the second capping layer 233_1 of the capping layer 230_1 of the display layer 200_1 according to some example embodiments can be selected in the range of about 45nm to 55nm, such that it is different from the second capping layer 233 of the capping layer 230 according to some example embodiments.

[0129] For example, the second thickness t2 of the second capping layer 233_1 of the capping layer 230_1 according to some example embodiments can be selected in the range of about 45nm to 55nm.

[0130] According to some example embodiments, such as Figure 12 As shown in the diagram, compared to Figure 6 Compared to the illustrated embodiment, the total amount of color temperature in the MPCD of the display device is smaller. For example, as described above, according to relative to... Figure 6 In the illustrated embodiment, the total change (dx) on the x-axis is approximately 0.038, and the total change (dy) on the y-axis is approximately 0.015, and according to relative to Figure 12 In the illustrated embodiment, the total change (dx) on the x-axis is approximately 0.011, and the total change (dy) on the y-axis is approximately 0.018. In other words, according to... Figure 12 Some example embodiments illustrated herein, and relative to Figure 6 Compared to the described embodiment, the change on the y-axis is 0.003 larger, but compared to... Figure 6 Compared to the illustrated embodiment, the change on the x-axis is 0.027 smaller.

[0131] According to some example embodiments, because the refractive index of the second capping layer 233_1 is greater than that of the first capping layer 231 and the third capping layer 235, and the second thickness t2 of the second capping layer 233_1 has a range of about 45 nm to about 55 nm, when viewed from a direction perpendicular to the substrate 100 (e.g., the z direction) and a direction tilted to the substrate 100, an increase in the total amount of shift in the color temperature direction in the minimum perceptible color difference (MPCD) due to thin film interference phenomena of the thin film encapsulation layer 300 can be prevented.

[0132] Figure 13 This is a schematic diagram illustrating a display device according to some example embodiments. Figure 14 This is a schematic diagram illustrating a display device according to some example embodiments.

[0133] Reference Figure 13 and Figure 14 Display device and Figure 4 The difference in the display device is that the cover layer 230_2 of the display layer 200_2 includes the above-mentioned reference. Figure 4The second capping layer 233 and the fourth capping layer 237 on the second capping layer 233 are described.

[0134] For example, the cover layer 230_2 of the display layer 200_2 of the display device according to some example embodiments may include the above-mentioned reference. Figure 4 The second capping layer 233 and the fourth capping layer 237 on the second capping layer 233 are described.

[0135] The fourth capping layer 237 can be disposed between the second capping layer 233 and the first inorganic encapsulation layer 310, and the first inorganic encapsulation layer 310 can be disposed between the fourth capping layer 237 and the auxiliary layer 315.

[0136] The fourth capping layer 237 can be inserted between the second capping layer 233 and the first inorganic encapsulation layer 310, and the first inorganic encapsulation layer 310 can be inserted between the fourth capping layer 237 and the auxiliary layer 315.

[0137] The refractive index of the fourth capping layer 237 can be less than the refractive index of the second capping layer 233 and greater than the refractive index of the thin-film encapsulation layer 300. The refractive index of the fourth capping layer 237 can be less than the refractive index of the second capping layer 233 and greater than the refractive index of the first inorganic encapsulation layer 310. In other words, the refractive index of the fourth capping layer 237 can have a value between the refractive index of the second capping layer 233 and the refractive index of the first inorganic encapsulation layer 310. Furthermore, the refractive index of the first inorganic encapsulation layer 310 can be greater than the refractive index of the auxiliary layer 315. That is, the refractive index can decrease in the order of the second capping layer 233, the fourth capping layer 237, the first inorganic encapsulation layer 310, the auxiliary layer 315, and the organic encapsulation layer 320.

[0138] For example, the refractive index of the second capping layer 233 and the refractive index of the fourth capping layer 237 may be about 1.77 or greater, the refractive index of the first inorganic encapsulation layer 310 may be equal to or less than 1.77, for example, it may be greater than 1.62 and equal to or less than 1.77, and the refractive index of the auxiliary layer 315 may be equal to or less than 1.62.

[0139] For example, the refractive index of the second capping layer 233 may be about 1.972, the refractive index of the fourth capping layer 237 may be about 1.87, the refractive index of the first inorganic encapsulation layer 310 may be about 1.77, and the refractive index of the auxiliary layer 315 may be about 1.62.

[0140] Conventionally, total internal reflection can occur at the interface when light travels from a medium with a high refractive index to a medium with a relatively low refractive index. Furthermore, the degree of total internal reflection may increase when the difference in refractive index between adjacent media relative to the interface is large.

[0141] When the light emitted from the display element moves upward, and the degree of total reflection increases at the interface between the second capping layer 233 and the fourth capping layer 237 and at the interface between the fourth capping layer 237 and the first inorganic encapsulation layer 310, the change in color coordinates can be large.

[0142] However, according to some example embodiments, the refractive index decreases in the order of the second capping layer 233, the fourth capping layer 237, the first inorganic encapsulation layer 310, and the auxiliary layer 315, and a fourth capping layer 237 is further arranged having a refractive index value between the refractive index value of the second capping layer 233 and the refractive index value of the first inorganic encapsulation layer 310, in order to reduce the large refractive index difference between the second capping layer 233 and the first inorganic encapsulation layer 310. Therefore, the degree of total internal reflection at the interface between the second capping layer 233 and the fourth capping layer 237, and at the interface between the fourth capping layer 237 and the first inorganic encapsulation layer 310, can be further reduced. Therefore, when light emitted from the display element moves upward, and the degree of total internal reflection between adjacent media at the interface between the second capping layer 233 and the fourth capping layer 237, and at the interface between the fourth capping layer 237 and the first inorganic encapsulation layer 310, the large change in color coordinates can be prevented in advance.

[0143] Figure 15 This is a schematic diagram illustrating a display device according to some embodiments. Figure 16 This is a schematic diagram illustrating a display device according to some embodiments.

[0144] Reference Figure 15 and Figure 16 According to some embodiments of this embodiment, the thin film encapsulation layer 300_1 of the display device is relative to... Figure 13 The difference in the thin-film encapsulation layer 300 of the described display device is that it may further include at least one auxiliary layer below the first inorganic encapsulation layer 310.

[0145] For example, such as Figure 15 and Figure 16 The thin-film encapsulation layer 300_1 illustrated may further include a lower auxiliary layer 350 located below the first inorganic encapsulation layer 310. That is, according to some embodiments, the thin-film encapsulation layer 300_1 may include a lower auxiliary layer 350, a first inorganic encapsulation layer 310, an auxiliary layer 315, an organic encapsulation layer 320, and a second inorganic encapsulation layer 330.

[0146] The lower auxiliary layer 350 can be located between the first inorganic encapsulation layer 310 and the fourth capping layer 237.

[0147] The lower auxiliary layer 350 can be inserted between the first inorganic encapsulation layer 310 and the fourth capping layer 237.

[0148] The refractive index of the lower auxiliary layer 350 can be less than the refractive index of the first inorganic encapsulation layer 310. The refractive index of the lower auxiliary layer 350 can be less than the refractive index of the fourth capping layer 237. That is, the refractive index of the lower auxiliary layer 350 can be less than each of the refractive indices of the first inorganic encapsulation layer 310 and the fourth capping layer 237.

[0149] As described above, the refractive index of the first inorganic encapsulation layer 310 can be greater than 1.62 and equal to or less than 1.77, and the refractive index of the fourth capping layer 237 can be equal to or greater than about 1.77. The difference between the refractive index of the lower auxiliary layer 350 and the refractive index of the fourth capping layer 237 can be greater than the difference between the refractive index of the lower auxiliary layer 350 and the refractive index of the first inorganic encapsulation layer 310. According to some embodiments, the refractive index of the lower auxiliary layer 350 can be equal to or greater than 1.4 and less than 1.62. For example, the refractive index of the lower auxiliary layer 350 can be about 1.57.

[0150] As referenced above Figure 13 As described, total internal reflection can occur at the interface when light propagates from a medium with a high refractive index to a medium with a relatively low refractive index. Furthermore, the degree of total internal reflection may increase when the refractive index difference between adjacent media relative to the interface is large.

[0151] In other words, as the light emitted by the display element moves upward, the change in color coordinates can be large when the total internal reflection between the adjacent medium at the interface between the fourth capping layer 237 and the first inorganic encapsulation layer 310 increases.

[0152] However, according to some embodiments, a lower auxiliary layer 350 can be further provided having a refractive index value between the refractive index value of the fourth capping layer 237 and the refractive index value of the first inorganic encapsulation layer 310, in order to reduce the large refractive index difference between the fourth capping layer 237 and the first inorganic encapsulation layer 310. Therefore, the degree of total internal reflection at the interface between the fourth capping layer 237 and the first inorganic encapsulation layer 310 can be further reduced. Thus, instances where the phenomenon of increased color coordinate variation can be prevented or reduced when light emitted from the display element moves upward and the degree of total internal reflection between adjacent media at the interface between the fourth capping layer 237 and the first inorganic encapsulation layer 310 increases can be prevented or reduced.

[0153] As described above, aspects of some embodiments according to this disclosure have been described with reference to some exemplary embodiments illustrated in the accompanying drawings. However, those skilled in the art will understand that various modifications and variations can be made to the embodiments. Therefore, the true scope of protection of this disclosure should be determined by the technical spirit of the appended claims and their equivalents.

Claims

1. A display device, comprising: substrate; Display elements are on the substrate; A cover layer is applied to the display element; as well as Thin film encapsulation layer, on the capping layer, The sealing layer includes: A first cover layer is applied to the display element; A second capping layer, on top of the first capping layer, has a refractive index greater than that of the first capping layer; and A third capping layer, situated on the second capping layer, has a refractive index lower than that of the second capping layer. The second capping layer has a thickness of 30 nm to 60 nm. The thin-film encapsulation layer includes a first inorganic encapsulation layer on the third capping layer, an auxiliary layer on the first inorganic encapsulation layer, and an organic encapsulation layer on the auxiliary layer. The first inorganic encapsulation layer has a refractive index greater than that of the auxiliary layer.

2. The display device according to claim 1, wherein, The second capping layer is inserted between the first capping layer and the third capping layer, and The second capping layer has a thickness of 30 nm to 40 nm.

3. The display device according to claim 2, wherein, The first capping layer has a thickness of 30 nm to 40 nm, and The third capping layer has a thickness of 35 nm to 45 nm.

4. The display device according to claim 3, wherein, The second capping layer has a refractive index in the range of 1.61 to 2.3, and Each of the first capping layer and the third capping layer has a refractive index in the range of 1.45 to 1.

6.

5. The display device according to claim 2, wherein, The thin-film encapsulation layer further includes a second inorganic encapsulation layer on the organic encapsulation layer.

6. The display device according to claim 5, wherein, The auxiliary layer has a thickness of 30 nm to 100 nm, and The first inorganic encapsulation layer has a thickness of 400 nm to 2200 nm.

7. The display device according to claim 6, wherein, The auxiliary layer is inserted between the first inorganic encapsulation layer and the organic encapsulation layer, and The auxiliary layer has a refractive index between that of the first inorganic encapsulation layer and the refractive index of the organic encapsulation layer.

8. The display device according to claim 7, wherein, The refractive index n3 of the auxiliary layer satisfies the following condition: min(n1, n2) + |n2 - n1| × 0.25 < n3 < min(n1, n2) + |n2 - n1| × 0.75, Wherein, n1 represents the refractive index of the first inorganic encapsulation layer, n2 represents the refractive index of the organic encapsulation layer, min(n1, n2) represents the minimum value of n1 and n2, and |n2 - n1| represents the absolute value of the difference between n2 and n1.

9. The display device according to claim 5, wherein, Each of the first inorganic encapsulation layer and the auxiliary layer comprises an inorganic insulating material.

10. The display device according to claim 5, further comprising: The lower layer is inserted between the auxiliary layer and the organic encapsulation layer.

11. The display device according to claim 10, wherein, The auxiliary layer has a refractive index greater than that of the organic encapsulation layer, and The lower layer has a refractive index between the refractive index of the auxiliary layer and the refractive index of the organic encapsulation layer.

12. The display device according to claim 11, wherein, The refractive index n3 of the auxiliary layer satisfies the following condition: min(n1, n2) + |n2 - n1| × 0.25 < n3 < min(n1, n2) + |n2 - n1| × 0.75, Wherein, n1 represents the refractive index of the first inorganic encapsulation layer, n2 represents the refractive index of the lower layer, min(n1,n2) represents the minimum value of n1 and n2, and |n2 - n1| represents the absolute value of the difference between n2 and n1.

13. The display device according to claim 11, wherein, The difference between the refractive index of the lower layer and the refractive index of the organic encapsulation layer is less than 0.05, and The lower layer comprises inorganic insulating material.

14. The display device according to claim 13, wherein, The lower layer and the auxiliary layer comprise an inorganic insulating material containing silicon, nitrogen, and oxygen. The oxygen content of the lower layer is greater than that of the auxiliary layer.

15. The display device according to claim 5, wherein, The first inorganic encapsulation layer comprises multiple stacked films.

16. The display device according to claim 1, wherein, The second capping layer is inserted between the first capping layer and the third capping layer, and The second capping layer has a thickness of 45 nm to 55 nm.

17. A display device, comprising: substrate; Organic light-emitting diodes are mounted on the substrate. A capping layer is applied to the organic light-emitting diode; as well as Thin film encapsulation layer, on the capping layer, The sealing layer includes: A first capping layer is applied to the organic light-emitting diode; A second capping layer, on top of the first capping layer, has a refractive index greater than that of the first capping layer; and A third capping layer, situated on the second capping layer, has a refractive index lower than that of the second capping layer. The second capping layer has a refractive index in the range of 1.61 to 2.3, and each of the first and third capping layers has a refractive index in the range of 1.45 to 1.

6. The second capping layer has a thickness of 30 nm to 60 nm. The thin-film encapsulation layer includes a first inorganic encapsulation layer on the third capping layer, an auxiliary layer on the first inorganic encapsulation layer, and an organic encapsulation layer on the auxiliary layer. The first inorganic encapsulation layer has a refractive index greater than that of the auxiliary layer.

18. The display device according to claim 17, wherein, The second capping layer is inserted between the first capping layer and the third capping layer, and The second capping layer has a thickness of 30 nm to 40 nm.

19. The display device according to claim 18, wherein, The first capping layer has a thickness of 30 nm to 40 nm, and The third capping layer has a thickness of 35 nm to 45 nm.

20. The display device according to claim 17, wherein, The second capping layer is inserted between the first capping layer and the third capping layer. The second capping layer has a thickness of 45 nm to 55 nm, and The first capping layer has a thickness of 30 nm to 40 nm, and the third capping layer has a thickness of 35 nm to 45 nm.

21. A display device, comprising: substrate; Display elements are on the substrate; A cover layer is applied to the display element; as well as Thin film encapsulation layer, on the capping layer, The sealing layer includes: A first cover layer is placed on the display element; and A second capping layer is located between the first capping layer and the thin-film encapsulation layer. The second capping layer is inserted between the first capping layer and the thin-film encapsulation layer. The second capping layer has a refractive index that is less than that of the first capping layer and greater than that of the thin-film encapsulation layer. The thin-film encapsulation layer includes a first inorganic encapsulation layer and an auxiliary layer on the first inorganic encapsulation layer, and The first inorganic encapsulation layer has a refractive index greater than that of the auxiliary layer.

22. The display device according to claim 21, wherein, The first inorganic encapsulation layer is inserted between the auxiliary layer and the second capping layer, and The second capping layer has a refractive index greater than that of the first inorganic encapsulation layer.

23. The display device according to claim 22, wherein, The second capping layer has a refractive index equal to or greater than 1.77, and The first inorganic encapsulation layer has a refractive index of less than 1.

77.

24. The display device according to claim 22, wherein, The thin-film encapsulation layer further includes a lower auxiliary layer between the second capping layer and the first inorganic encapsulation layer, and The lower auxiliary layer has a refractive index between the refractive index of the second capping layer and the refractive index of the first inorganic encapsulation layer.

25. The display device according to claim 24, wherein, The lower auxiliary layer is inserted between the second capping layer and the first inorganic encapsulation layer.

26. The display device according to claim 25, wherein, The refractive index difference between the lower auxiliary layer and the second capping layer is greater than the refractive index difference between the lower auxiliary layer and the first inorganic encapsulation layer.

27. The display device according to claim 26, wherein, The refractive index of the lower auxiliary layer has a value equal to or greater than 1.4 and less than 1.62.

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