Display device and method for manufacturing a display device

Abstract

This disclosure relates to a display device and a method of manufacturing the display device. The display device includes a substrate. A display element is disposed above the substrate. A first inorganic encapsulation layer is disposed on the display element. An organic encapsulation layer is disposed on the first inorganic encapsulation layer. An auxiliary layer is disposed between the first inorganic encapsulation layer and the organic encapsulation layer. The auxiliary layer has a thickness of less than approximately 100 nm and comprises an inorganic insulating material. A second inorganic encapsulation layer is disposed on the organic encapsulation layer.

Description

[0001] This application is a divisional application, the parent application being the invention patent application filed on May 25, 2020, with application number 202010449832.7 and title "Display Device". Cross-reference to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2019-0062056, filed on May 27, 2019, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a display device and a method of manufacturing the same, and more specifically, to a display device including a packaging structure and a method of manufacturing the same. Background Technology

[0004] Display devices have been integrated into a wide variety of electronic devices. This has allowed display devices to evolve across a range of sizes and shapes. With advancements in display technology, display devices have become thinner and lighter. As display devices are now used under a wide variety of conditions, there is a growing focus on making them more robust and able to withstand various adverse conditions and environments. However, ideally, the protective structure of a display device should not interfere with display quality. Summary of the Invention

[0005] This disclosure aims to provide a display device for preventing color difference in light emitted from a display element and encapsulating the display element to prevent it from being affected by external impurities, while minimizing the thickness of the display device.

[0006] A display device includes a substrate. A display element is disposed above the substrate. A first inorganic encapsulation layer is disposed on the display element. An organic encapsulation layer is disposed on the first inorganic encapsulation layer. An auxiliary layer is disposed between the first inorganic encapsulation layer and the organic encapsulation layer. The auxiliary layer has a thickness of less than approximately 100 nm and comprises an inorganic insulating material. A second inorganic encapsulation layer is disposed on the organic encapsulation layer.

[0007] The thickness t of the auxiliary layer can be in the range of 30nm ≤ t < 100nm.

[0008] The thickness T of the first inorganic encapsulation layer can be in the range of 600nm ≤ T ≤ 2200nm.

[0009] The auxiliary layer can directly contact the top surface of the first inorganic encapsulation layer, and the refractive index n3 of the auxiliary layer can satisfy the following condition: min(n1, n2) + |n2 - n1| × 0.25 <n3<min(n1, n2)+|n2-n1| × 0.75, Wherein, n1 is the refractive index of the first inorganic encapsulation layer, n2 is the refractive index of the organic encapsulation layer, min(n1, n2) is the minimum value of n1 and n2, and |n2-n1| is the absolute value of the difference between n2 and n1.

[0010] Both the first inorganic encapsulation layer and the auxiliary layer may contain non-metallic elements. The non-metallic elements contained in the first inorganic encapsulation layer may be the same as those contained in the auxiliary layer.

[0011] Both the first inorganic encapsulation layer and the auxiliary layer may include silicon oxynitride, and the refractive index of the first inorganic encapsulation layer may be different from the refractive index of the auxiliary layer.

[0012] The organic encapsulation layer can directly contact the top surface of the auxiliary layer.

[0013] The display device may further include a bottom layer disposed between the auxiliary layer and the organic encapsulation layer.

[0014] The difference between the refractive index of the bottom layer and the refractive index of the organic encapsulation layer can be less than approximately 0.05.

[0015] The underlying layer may include inorganic insulating materials.

[0016] The bottom layer may contain the same non-metallic elements as the auxiliary layer.

[0017] The bottom layer and the auxiliary layer may comprise an inorganic insulating material containing silicon, nitrogen, and oxygen. The oxygen content of the bottom layer may be greater than that of the auxiliary layer.

[0018] A display device includes a substrate. A plurality of organic light-emitting diodes (OLEDs) are disposed above the substrate. A first inorganic encapsulation layer covers the plurality of OLEDs. A second inorganic encapsulation layer is disposed above the first inorganic encapsulation layer. An organic encapsulation layer is disposed between the first inorganic encapsulation layer and the second inorganic encapsulation layer. An auxiliary layer is disposed between the first inorganic encapsulation layer and the organic encapsulation layer. The thickness of the auxiliary layer is less than the thickness of the first inorganic encapsulation layer, and the auxiliary layer satisfies the following condition: 30nm≤t<100nm, Where t is the thickness of the auxiliary layer.

[0019] The thickness T of the first inorganic encapsulation layer can be in the range of 600nm ≤ T ≤ 2200nm.

[0020] The first inorganic encapsulation layer, the auxiliary layer, and the second inorganic encapsulation layer may all include inorganic insulating materials containing non-metallic elements.

[0021] The refractive index n3 of the auxiliary layer can satisfy the following condition: min(n1, n2) + |n2 - n1| × 0.25 <n3<min(n1, n2)+|n2-n1|×0.75, Wherein, n1 is the refractive index of the first inorganic encapsulation layer, n2 is the refractive index of the organic encapsulation layer, min(n1, n2) is the minimum value of n1 and n2, and |n2-n1| is the absolute value of the difference between n2 and n1.

[0022] The non-metallic elements contained in the first inorganic encapsulation layer can be the same as those contained in the auxiliary layer, and the refractive index of the auxiliary layer can be less than that of the first inorganic encapsulation layer.

[0023] The auxiliary layer can directly contact the first inorganic encapsulation layer and the organic encapsulation layer.

[0024] The display device may further include a bottom layer disposed between the auxiliary layer and the organic encapsulation layer. The difference between the refractive index of the bottom layer and the refractive index of the organic encapsulation layer is less than approximately 0.05.

[0025] The bottom layer may include inorganic insulating material and may directly contact the auxiliary layer and the organic encapsulation layer. Attached Figure Description

[0026] A more complete understanding of this disclosure and its many accompanying aspects will readily become apparent from the following description taken in conjunction with the accompanying drawings, in which: Figure 1 This is a plan view showing a display device according to an exemplary embodiment of the present disclosure; Figure 2 This is a schematic diagram showing a display element and pixel circuits connected thereto, the pixel circuits being arranged in one of the pixel regions of a display device according to an exemplary embodiment of the present disclosure; Figure 3 This is a cross-sectional view showing a portion of a display device according to an exemplary embodiment of the present disclosure; Figure 4 This is a cross-sectional view showing a portion of a display device according to an exemplary embodiment of the present disclosure; Figure 5 This is a cross-sectional view showing a display device according to an exemplary embodiment of the present disclosure; Figure 6 This is a graph showing the simulation results of minimum perceived color difference (MPCD) based on the thickness variations of the first inorganic encapsulation layer and the auxiliary layer; Figure 7 This is a graph showing the simulation results of MPCD based on the thickness variation of the first inorganic encapsulation layer and the refractive index variation of the auxiliary layer; Figure 8 This is a cross-sectional view showing a display device according to an exemplary embodiment of the present disclosure; Figure 9 This is a cross-sectional view showing a portion of a display device according to an exemplary embodiment of the present disclosure; Figures 10A to 10D These are diagrams representing MPCDs relative to a viewing angle, respectively, according to exemplary embodiments of the present disclosure; and Figure 10E and Figure 10F These are diagrams showing the MPCD relative to the viewing angle, based on comparative examples. Detailed Implementation

[0027] In describing exemplary embodiments of the present disclosure illustrated in the accompanying drawings, specific terminology is used for clarity. However, the present disclosure is not intended to be limited to the specific terminology chosen so far, and it should be understood that each specific element includes all technical equivalents that operate in a similar manner.

[0028] In the accompanying drawings and description, the same reference numerals may denote the same or corresponding elements, and to the extent that repeated descriptions have been omitted, it may be assumed that the omitted descriptions are at least similar to the descriptions of the corresponding elements described elsewhere in the description.

[0029] It will be understood that although the terms “first,” “second,” etc., may be used in this document to describe various components, these components should not be limited by these terms. These terms are used only to distinguish one component from another.

[0030] It will also be understood that the terms “including / comprises” and / or “contains / have” as used herein indicate the presence of the stated features or components, but do not exclude the presence or addition of one or more other features or components. However, the phrase “composes of” is used herein to exclude the presence or addition of other features or components.

[0031] It will be understood that when a layer, region, or component is said to be “formed on” another layer, region, or component, it can be formed directly or indirectly on that other layer, region, or component. That is, for example, intermediate layers, regions, or components may exist.

[0032] For ease of illustration, the dimensions of the elements in the accompanying drawings may be exaggerated. While the lengths, angles, thicknesses, and relative arrangements of the various elements shown in the figures may be interpreted as details relating to a particular example, it is understood that these values ​​may be changed without departing from the spirit and scope of this disclosure.

[0033] It should be understood that the elements described herein with respect to specific embodiments can be rearranged to form different embodiments, and the steps described herein can be rearranged to be performed in a different order, and one or more of the described steps can be performed substantially simultaneously. For example, two consecutively described processes can be performed substantially simultaneously or in the reverse order of their description.

[0034] It will be understood that when a layer, region, or component is referred to as being "connected" to another layer, region, or component, it can be "directly connected" to another layer, region, or component, or it can be "indirectly connected" to another layer, region, or component with other layers, regions, or components arranged between them. For example, it will be understood that when a layer, region, or component is referred to as being "electrically connected" to another layer, region, or component, it can be "directly electrically connected" to another layer, region, or component, or it can be "indirectly electrically connected" to another layer, region, or component with other layers, regions, or components arranged between them.

[0035] In the examples 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 broader sense. For example, the x-axis, y-axis, and z-axis can be perpendicular to each other, or they can represent different directions that are not perpendicular to each other.

[0036] Figure 1 This is a plan view showing a display device 10 according to an exemplary embodiment of the present disclosure.

[0037] Reference Figure 1 The display device 10 may include a display area DA and a non-display area NDA that at least partially surrounds the display area DA. The display device 10 includes a plurality of pixel areas P disposed therein. A display element emitting light of a predetermined color may be disposed in each pixel area P. The display element may be connected to a scan line SL and a data line DL. The display area DA and the non-display area NDA may each be part of a substrate 100 of the display device 10. For example, it is understood that the substrate 100 includes the display area DA and the non-display area NDA.

[0038] The scan driver 1100, data driver 1200, and main power line can be arranged in the non-display area NDA. The scan driver 1100 provides a scan signal to each pixel area P via the scan line SL. The data driver 1200 provides a data signal to each pixel area P via the data line DL. The main power line provides a first power supply voltage and a second power supply voltage.

[0039] Despite Figure 1 The diagram shows a data driver 1200 disposed on a substrate 100, but 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.

[0040] The display device 10 according to exemplary embodiments of the present disclosure may include an organic light-emitting display, an inorganic light-emitting display, and a quantum dot display. Although the display device according to exemplary embodiments of the present disclosure is described as an organic light-emitting display device by way of example, the display device according to the present disclosure is not limited thereto, and the features described below are applicable to various types of display devices.

[0041] Figure 2 This is a schematic diagram showing a display element and a pixel circuit PC connected thereto, the pixel circuit PC being arranged in one of the pixel regions P of a display device according to an exemplary embodiment of the present disclosure.

[0042] Reference Figure 2 An organic light-emitting diode (OLED) as a display element 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 can emit red, green, and blue light, or it can emit red, green, blue, and white light.

[0043] The second thin-film transistor T2 includes a switching thin-film transistor and is connected to the scan line SL and the data line DL. In response to a switching voltage input through the scan line SL, the second thin-film transistor T2 transmits a data voltage input through the data line DL to the first thin-film transistor T1. A storage capacitor Cst can be connected to the second thin-film transistor T2 and the drive voltage line PL, and can store a voltage corresponding to the difference between the voltage transmitted from the second thin-film transistor T2 and the first power supply voltage ELVDD supplied through the drive voltage line PL.

[0044] The first thin-film transistor T1 can be a driving thin-film transistor 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 stored in the storage capacitor Cst. The OLED can emit light with a predetermined brightness according to the driving current. The opposite electrode (e.g., the cathode) of the OLED can receive a second power supply voltage ELVSS.

[0045] Despite Figure 2 The pixel circuit PC is described as including two thin-film transistors T1 and T2 and a storage capacitor Cst, but the number of thin-film transistors and the number of storage capacitors can be varied depending on the design of the pixel circuit PC.

[0046] Figure 3 and Figure 4 This is a cross-sectional view showing a portion of a display device 10 according to an exemplary embodiment of the present disclosure.

[0047] Reference Figure 3 and Figure 4 A pixel circuit layer PCL is disposed on the substrate 100, and an organic light-emitting diode (OLED) serving as a display element is disposed on the pixel circuit layer PCL and covered by a thin-film encapsulation layer 300. The pixel circuit layer PCL includes pixel circuits PC.

[0048] The substrate 100 may include a glass material or a polymer resin. The substrate 100 comprising a polymer resin may be flexible, rollable, and / or bendable.

[0049] In exemplary embodiments of this disclosure, the substrate 100 may include a first substrate layer 101, a first barrier layer 102, a second substrate layer 103, and a second barrier layer 104, such as... Figure 3 As shown in the diagram. The first substrate layer 101 and the second substrate layer 103 may include polymer resins. For example, the first substrate layer 101 and the second substrate layer 103 may include polymer resins including polyethersulfone (PES), polyaryl compounds (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyarylate, polyimide (PI), polycarbonate (PC), cellulose triacetate (TAC), and / or cellulose acetate propionate (CAP). The first barrier layer 102 and the second barrier layer 104 are barrier layers that prevent the penetration of external foreign substances and may include single-layer or multi-layer structures, including inorganic materials such as silicon nitride and silicon oxide.

[0050] According to exemplary embodiments of the present disclosure, substrate 100 may include a single layer, the single layer including a glass material, such as... Figure 4 As shown in the figure. For example, substrate 100 may include a glass substrate, wherein the glass substrate includes SiO2 as its main component.

[0051] The pixel circuit layer PCL on substrate 100 may include thin-film transistors (TFTs). The pixel circuit layer PCL may include storage capacitors connected to the TFTs. Each pixel TFT may have the same structure. Each TFT may be connected to a display element supplied to each pixel.

[0052] A thin-film transistor (TFT) may include a semiconductor layer ACT, a gate electrode GE, a source electrode SE, and a drain electrode DE. The semiconductor layer ACT may include amorphous silicon, polycrystalline silicon, and / or organic semiconductor materials. To ensure insulation between the semiconductor layer ACT and the gate electrode GE, a gate insulating layer 121 may be disposed between the semiconductor layer ACT and the gate electrode GE. The gate insulating layer 121 may include inorganic materials such as silicon oxide, silicon nitride, and / or silicon oxynitride. An interlayer insulating layer 131 may be disposed on the gate electrode GE. The interlayer insulating layer 131 may include inorganic materials such as silicon oxide, silicon nitride, and / or silicon oxynitride. The source electrode SE and the drain electrode DE may both be disposed on the interlayer insulating layer 131. The gate insulating layer 121 and the interlayer insulating layer 131 may include inorganic materials that can be formed by chemical vapor deposition (CVD) and / or atomic layer deposition (ALD).

[0053] The gate electrode GE, source electrode SE, and drain electrode DE can comprise various conductive materials. The gate electrode GE can comprise molybdenum or aluminum and can have a single-layer or multi-layer structure. For example, the gate electrode GE can comprise a single molybdenum layer, or it can have a three-layer structure comprising a molybdenum layer, an aluminum layer, and a molybdenum layer. The source electrode SE and drain electrode DE can both comprise titanium or aluminum and can both have a single-layer or multi-layer structure. In an exemplary embodiment of this disclosure, both the source electrode SE and drain electrode DE can have a three-layer structure comprising a titanium layer, an aluminum layer, and a titanium layer.

[0054] A buffer layer 110 may be disposed between the thin-film transistor TFT having the above-described structure and the substrate 100. The buffer layer 110 comprises an inorganic material, such as silicon oxide, silicon nitride, and / or silicon oxynitride. The buffer layer 110 may increase the flatness of the top surface of the substrate 100, or may prevent or minimize the penetration of impurities from the substrate 100 into the semiconductor layer ACT of the thin-film transistor TFT.

[0055] The planarization insulating layer 140 can be disposed on a thin-film transistor (TFT). The planarization insulating layer 140 may include organic materials such as acrylic resin, benzocyclobutene (BCB), or hexamethyldisiloxane (HMDSO). The planarization insulating layer 140 may be a single layer or a multilayer structure.

[0056] Organic light-emitting diodes (OLEDs) include pixel electrodes 221, intermediate layers 222, and relative electrodes 223.

[0057] Pixel electrodes 221 can be disposed on the planarization insulating layer 140 and can be disposed one-to-one for each pixel. Pixel electrodes 221 may include reflective electrodes. In exemplary embodiments of this disclosure, pixel electrodes 221 may include a reflective layer comprising Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, and / or Cr. In exemplary embodiments of this disclosure, pixel electrodes 221 may include transparent or translucent electrode layers disposed above / below the reflective layer. The transparent or translucent electrode layers may include indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In2O3), indium gallium oxide (IGO), and / or aluminum zinc oxide (AZO). In exemplary embodiments of this disclosure, pixel electrodes 221 may have a three-layer structure consisting of an ITO layer, an Ag layer, and an ITO layer.

[0058] A pixel defining layer 150 is disposed on the pixel electrode 221. The pixel defining layer 150 includes an opening 150OP exposing the central portion of each pixel electrode 221. The pixel defining layer 150 can prevent arcing or the like at the edges of the pixel electrode 221 by increasing the distance between the opposing electrode 223 and the edges of the pixel electrode 221. The pixel defining layer 150 may comprise an organic insulating material such as polyimide, polyamide, acrylic resin, BCB, HMDSO, and phenolic resin, and can be formed by a method such as spin coating.

[0059] The emitting layer 222b may be disposed on the portion of the pixel electrode 221 exposed through the opening 150OP of the pixel defining layer 150. The emitting layer 222b may include an organic material, including fluorescent or phosphorescent materials, capable of emitting red, green, or blue light. The organic material may include low molecular weight organic materials or polymeric organic materials.

[0060] The first functional layer 222a and the second functional layer 222c can be disposed below and on the emitter layer 222b, respectively. The first functional layer 222a may include, for example, a hole transport layer (HTL), or may include an HTL and a hole injection layer (HIL). The second functional layer 222c is an element disposed on the emitter layer 222b and may include an electron transport layer (ETL) and / or an electron injection layer (EIL). The second functional layer 222c is optional and may be omitted. In exemplary embodiments of this disclosure, the second functional layer 222c may be omitted.

[0061] The emission layer 222b is arranged to correspond to the openings 150OP of the pixel limiting layer 150.

[0062] In contrast, similar to the opposing electrode 223 described below, the first functional layer 222a and the second functional layer 222c may be a common layer formed integrally to completely cover the substrate 100, for example, completely covering the display area DA of the substrate 100.

[0063] The counter electrode 223 may include a (semi-)transparent layer, which may include Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, and / or Ca. Optionally, the counter electrode 223 may also include a layer located on the (semi-)transparent layer comprising the above materials, the layer comprising ITO, IZO, ZnO, and / or In2O3. In exemplary embodiments of this disclosure, the counter electrode 223 may include Ag, Mg, or an alloy of Ag and Mg.

[0064] The capping layer 230 may be positioned on the opposing electrode 223. For example, the capping layer 230 may include LiF, an inorganic insulating material, or an organic insulating material. In exemplary embodiments of this disclosure, the capping layer 230 may be omitted.

[0065] The thin-film encapsulation layer 300 may include at least one inorganic encapsulation layer and at least one organic encapsulation layer. For example, the thin-film encapsulation layer 300 includes a first inorganic encapsulation layer 310, an organic encapsulation layer 320, and a second inorganic encapsulation layer 330, and includes an auxiliary layer 315 located between the first inorganic encapsulation layer 310 and the organic encapsulation layer 320, such as... Figure 4 As shown in the image.

[0066] The first inorganic encapsulation layer 310 and the second inorganic encapsulation layer 330 may include inorganic insulating materials, such as aluminum oxide, titanium oxide, tantalum oxide, hafnium oxide, zinc oxide, silicon oxide, silicon nitride, and / or silicon oxynitride. In exemplary embodiments of this disclosure, both the first inorganic encapsulation layer 310 and the second inorganic encapsulation layer 330 may include inorganic insulating materials containing non-metallic elements, such as silicon oxide, silicon nitride, and / or silicon oxynitride. The quantity and type of non-metallic elements contained in the first inorganic encapsulation layer 310 may differ from the quantity and type of non-metallic elements contained in the second inorganic encapsulation layer 330. For example, the first inorganic encapsulation layer 310 may include silicon oxynitride, and the second inorganic encapsulation layer 330 may include silicon nitride.

[0067] The first inorganic encapsulation layer 310 may have a thickness T ranging from approximately 600 nm to approximately 2200 nm (600 nm ≤ T ≤ 2200 nm). If the thickness T of the first inorganic encapsulation layer 310 deviates from the lower limit (e.g., less than 600 nm), moisture transport may occur. If the thickness T of the first inorganic encapsulation layer 310 deviates from the upper limit, the first inorganic encapsulation layer 310 may detach or separate. The thickness of the second inorganic encapsulation layer 330 may be equal to, less than, or greater than the thickness of the first inorganic encapsulation layer 310.

[0068] The organic encapsulation layer 320 can alleviate the internal stress of the first inorganic encapsulation layer 310 and / or the second inorganic encapsulation layer 330. The organic encapsulation layer 320 may include polymeric materials. Polymeric materials may include PET, PEN, PC, PI, polyvinyl sulfonate, polyoxymethylene, polyarylate, HMDSO, acrylic resins (e.g., polymethyl methacrylate, polyacrylic acid, etc.) or any combination thereof.

[0069] The organic encapsulation layer 320 can be formed by coating with a monomer that has flowability; and then curing the monomer layer by using heat or light such as ultraviolet light. Alternatively, the organic encapsulation layer 320 can be formed by coating with a polymeric material.

[0070] An auxiliary layer 315 is disposed 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.

[0071] The auxiliary layer 315 may include an inorganic insulating material comprising non-metallic elements. In an exemplary embodiment of this disclosure, the non-metallic elements included in the auxiliary layer 315 may be the same non-metallic elements as those in the first inorganic encapsulation layer 310. The non-metallic elements may include, for example, Si, O, and / or N.

[0072] Light emitted from the organic light-emitting diodes (OLEDs) arranged for each pixel passes through the thin-film encapsulation layer 300 and travels in parallel to the outside. In this case, due to thin-film interference phenomena in the thin-film encapsulation layer 300, when viewing the image in a direction tilted relative to the direction perpendicular to the substrate 100 (e.g., the z-direction), the image seen by the user may appear reddish (e.g., each color may appear redder than it should be). However, because the thin-film encapsulation layer 300 includes an auxiliary layer 315, the reddish image problem can be prevented. (Refer to below...) Figure 5 Describe the specific characteristics of the thin-film encapsulation layer 300.

[0073] Figure 5 This is a cross-sectional view showing a display device 10 according to an exemplary embodiment of the present disclosure.

[0074] Reference Figure 5 The display device 10 includes a substrate 100, a pixel circuit layer PCL, a display layer 200, and a thin film encapsulation layer 300 stacked sequentially. The display layer 200 includes a pixel electrode 221, an intermediate layer 222, a counter electrode 223, and a capping layer 230.

[0075] The thin-film encapsulation layer 300 may include a first inorganic encapsulation layer 310 and an auxiliary layer 315 sequentially stacked in the direction of light propagation (or from the display layer 200 toward the thin-film encapsulation layer 300). An organic encapsulation layer 320 and a second inorganic encapsulation layer 330 may be disposed on the auxiliary layer 315.

[0076] While adjusting the thickness of the first inorganic encapsulation layer 310 can be considered a method for solving the aforementioned reddish tint problem, its thickness may be difficult to control due to the limitations of the manufacturing equipment (e.g., CVD equipment) used to form the first inorganic encapsulation layer 310. For example, the first inorganic encapsulation layer 310 may have a thickness ranging from approximately 600 nm to approximately 2200 nm, as described above, to protect the display layer 200 from moisture and other influences and prevent the separation of the first inorganic encapsulation layer 310. With an error margin of approximately 10% for the equipment used to form the inorganic insulating layer, the actual thickness deviation of the first inorganic encapsulation layer 310 formed corresponds to a range of tens to hundreds of nanometers, making it practically difficult to control the thickness of the first inorganic encapsulation layer 310. Therefore, there are limitations in solving the aforementioned reddish tint problem.

[0077] The thin-film encapsulation layer 300 according to an exemplary embodiment of the present disclosure has the advantage of easily solving the redness problem without being limited by the thickness of the first inorganic encapsulation layer 310 by arranging an auxiliary layer 315 on the first inorganic encapsulation layer 310.

[0078] The auxiliary layer 315 may include an inorganic insulating material. To minimize or prevent the reddish tint problem, the thickness t of the auxiliary layer 315 may be less than approximately 100 nm. For example, the thickness t of the auxiliary layer 315 may be equal to or greater than 30 nm and less than 100 nm (30 nm ≤ t < 100 nm).

[0079] Figure 6 This is a graph showing the minimum perceived color difference (MPCD) based on the thickness variations of the first inorganic encapsulation layer 310 and the auxiliary layer 315. Figure 6 In the diagram, the MPCD is displayed as an outline by dividing it into predetermined segments. When the MPCD has a (-) value in the direction away from zero, the MPCD is reddish. When the MPCD has a (+) value in the direction away from zero, the MPCD is greenish. Figure 6 The simulation results represent the case where the first inorganic encapsulation layer 310 and the auxiliary layer 315 each comprise silicon oxynitride layers with different refractive indices. When the display device 10 is viewed in a direction inclined relative to the direction perpendicular to the substrate 100, for example, as... Figure 5 As shown, when viewed at an angle of approximately 30° (θ=30°) relative to the z-direction, the outline of the MPCD is displayed based on the MPCD value.

[0080] Reference Figure 6 It was found that when the thickness t of the auxiliary layer 315 is in the range of 30nm ≤ t < 100nm, the change in MPCD is small. When the thickness t of the auxiliary layer 315 meets the above range, the reddish problem can be minimized or prevented, and is not limited by the thickness T of the first inorganic encapsulation layer 310.

[0081] The auxiliary layer 315 may include an inorganic insulating material. In the inorganic insulating layer formed by the CVD apparatus, the actual thickness of the formed inorganic insulating layer will have an error of approximately 10% compared to the target thickness described above. Because the auxiliary layer 315, like the first inorganic encapsulation layer 310, can be formed using a CVD apparatus, the actual thickness of the formed auxiliary layer 315 may differ from the target thickness. However, because the thickness of the auxiliary layer 315 is one-tenth or less of the thickness of the first inorganic encapsulation layer 310, controlling the thickness of the auxiliary layer 315 is still easier, even considering the thickness error of the CVD apparatus (e.g., approximately 10%).

[0082] When the auxiliary layer 315 deviates from the aforementioned thickness range (e.g., deviates from the lower limit), the MPCD variation increases. When the auxiliary layer 315 deviates from the upper limit, the MPCD variation increases and / or the thickness of the auxiliary layer 315 becomes difficult to control. Therefore, it is difficult to expect the auxiliary layer 315 to prevent the reddening problem when the thickness of the first inorganic encapsulation layer 310 is unrestricted.

[0083] As described above, the auxiliary layer 315 may include an inorganic insulating material comprising non-metallic elements. In exemplary embodiments of this disclosure, the auxiliary layer 315 may contain the same non-metallic elements as the first inorganic encapsulation layer 310. For example, both the auxiliary layer 315 and the first inorganic encapsulation layer 310 may contain Si, O, and N. Therefore, the first inorganic encapsulation layer 310 and the auxiliary layer 315 can be formed by changing the gas composition in the same CVD apparatus (or the same chamber). For example, the auxiliary layer 315 and the first inorganic encapsulation layer 310 may include silicon oxynitride layers with different Si, O, and N contents / concentrations. The gas composition during the process of forming the first inorganic encapsulation layer 310 may differ from the gas composition during the process of forming the auxiliary layer 315. Therefore, an interface may exist between them, such as... Figure 5 As shown in the image.

[0084] 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.

[0085] min(n1, n2) + |n2 - n1| × 0.25 <n3<min(n1, n2)+|n2-n1|×0.75 Here, n1 is the refractive index of the first inorganic encapsulation layer 310, n2 is the refractive index of the organic encapsulation layer 320, min(n1,n2) is the minimum value of n1 and n2, and |n2-n1| is the absolute value of the difference between n2 and n1.

[0086] When the refractive index n3 of the auxiliary layer 315 deviates from the above range, the MPCD will change significantly, making it difficult to prevent the reddish tint problem.

[0087] Figure 7 This is a graph showing the MPCD based on the thickness variation of the first inorganic encapsulation layer 310 and the refractive index variation of the auxiliary layer 315. (Compared to...) Figure 6 Similarly, MPCD is a simulation result under the condition that the first inorganic encapsulation layer 310 and the auxiliary layer 315 each include silicon oxynitride layers, and the display device 10 is viewed from a position tilted relative to the direction perpendicular to the substrate 100, for example, when viewed relative to... Figure 5 When viewing the display device 10 at an angle of approximately 30° (θ=30°) in the z-direction. (Refer to...) Figure 7 When the refractive index of the auxiliary layer 315 is in the range of approximately 1.57 to approximately 1.70, the variation in MPCD is relatively small. The refractive index of the auxiliary layer 315 can be less than the refractive index of the first inorganic encapsulation layer 310.

[0088] Figure 8This is a block diagram illustrating a display device 10 according to an exemplary embodiment of the present disclosure.

[0089] Reference Figure 8 The display device 10 may include a substrate 100, a pixel circuit layer PCL, a display layer 200, and a thin-film encapsulation layer 300'. The thin-film encapsulation layer 300' may further include a bottom layer 325 disposed beneath the organic encapsulation layer 320. Because the remaining components besides the bottom layer 325 are related to the reference... Figures 5 to 7 The components of the described embodiments are the same, so the underlying layer 325 will be mainly described below.

[0090] The bottom layer 325 does not necessarily act as a thin-film encapsulation layer; for example, it can transport moisture. The materials constituting the organic encapsulation layer 320 can be controlled during the process of forming the organic encapsulation layer 320 by coating and curing the monomers. As described above, the bottom layer 325 not only has moisture transport properties but also has separate optical functions. The refractive index of the bottom layer 325 can be substantially the same as the refractive index of the organic encapsulation layer 320. Because the refractive index of the bottom layer 325 can be substantially the same as the refractive index of the organic encapsulation layer 320, the difference Δn between the refractive indices of the bottom layer 325 and the organic encapsulation layer 320 is less than 0.05. In an exemplary embodiment of this disclosure, the refractive index of the bottom layer 325 can be approximately 1.52. The thickness of the bottom layer 325 can be in the range of approximately 500 Å to approximately 1000 Å. For example, the thickness of the bottom layer 325 can be in the range of approximately 550 Å to approximately 900 Å, or approximately 600 Å to approximately 850 Å. Because the refractive index of the bottom layer 325 is substantially the same as that of the organic encapsulation layer 320, and the bottom layer 325 includes materials different from those of the organic encapsulation layer 320, there is an interface between the bottom layer 325 and the organic encapsulation layer 320.

[0091] The bottom layer 325 may include an inorganic insulating layer. In exemplary embodiments of this disclosure, the bottom layer 325 may contain the same non-metallic elements as the non-metallic elements in the first inorganic encapsulation layer 310 and the auxiliary layer 315, or it may contain non-metallic elements different from those contained in the first inorganic encapsulation layer 310 and the auxiliary layer 315. For example, the bottom layer 325 may include an inorganic insulating layer with a relatively high oxygen content; for instance, the bottom layer 325 may include an oxygen-rich silicon oxynitride layer.

[0092] In exemplary embodiments of this disclosure, the first inorganic encapsulation layer 310, the auxiliary layer 315, and the bottom layer 325 may all contain the same non-metallic elements, such as Si, O, and 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 bottom layer 325 may each contain different ratios and / or concentrations of Si, O, and N. Therefore, interfaces may exist between the first and second silicon oxynitride layers and between the second and third silicon oxynitride layers.

[0093] Figure 9 This is a cross-sectional view showing a portion of a display device 10 according to an exemplary embodiment of the present disclosure.

[0094] Reference Figure 9 Organic light-emitting diodes (OLEDs) as display elements are arranged in each pixel of the substrate 100. Each OLED can be electrically connected to a thin-film transistor (TFT) provided to the pixel circuit layer PCL. The substrate 100, the pixel circuit layer PCL, and the OLEDs can be connected in conjunction with the above-mentioned reference. Figure 3 The descriptions are the same.

[0095] Each pixel of the organic light-emitting diode (OLED) can be covered by a thin-film encapsulation layer 300'. The thin-film encapsulation layer 300' may include a first inorganic encapsulation layer 310, an auxiliary layer 315, a bottom layer 325, an organic encapsulation layer 320, and a second inorganic encapsulation layer 330, stacked sequentially (e.g., in the listed order) in a direction away from the substrate 100 (e.g., the z-direction). The first inorganic encapsulation layer 310, the auxiliary layer 315, the bottom layer 325, the organic encapsulation layer 320, and the second inorganic encapsulation layer 330 can be referenced. Figures 3 to 8 The descriptions are the same.

[0096] The first inorganic encapsulation layer 310, the auxiliary layer 315, and the bottom layer 325 may include different non-metallic elements or the same non-metallic elements. Non-metallic elements may include, for example, Si, O, and N.

[0097] In exemplary embodiments of this disclosure, the first inorganic encapsulation layer 310, the auxiliary layer 315, and the bottom layer 325 may all comprise a silicon oxynitride layer containing Si, O, and N. However, the characteristics (e.g., refractive indices) of the first inorganic encapsulation layer 310, the auxiliary layer 315, and the bottom layer 325 may differ from each other. The third silicon oxynitride layer serving as the bottom layer 325 has a relatively high oxygen content (e.g., oxygen-rich), and the refractive index of the third silicon oxynitride layer may be lower than the refractive index of the first silicon oxynitride layer serving as the first inorganic encapsulation layer 310 and the refractive index of the second silicon oxynitride layer serving as the auxiliary layer 315.

[0098] Even though the first inorganic encapsulation layer 310, the auxiliary layer 315, and the bottom layer 325 all contain the same non-metallic elements, they are formed during separate processes. The processes for forming the first inorganic encapsulation layer 310, the auxiliary layer 315, and the bottom layer 325 are performed sequentially in separate processes (e.g., using different proportions of reactant gases or using different types of reactant gases in the same chamber). The auxiliary layer 315 is disposed precisely on the first inorganic encapsulation layer 310, and the bottom layer 325 is disposed precisely on the auxiliary layer 315. Interfaces exist between the first inorganic encapsulation layer 310 and the auxiliary layer 315, and between the auxiliary layer 315 and the bottom layer 325. These interfaces are visible to the observer in a cross-sectional view.

[0099] The process of forming the organic encapsulation layer 320 can be performed after the process of forming the organic encapsulation layer 325. The process of forming the second inorganic encapsulation layer 330 can be performed after the process of forming the organic encapsulation layer 320. Therefore, the bottom layer 325 and the organic encapsulation layer 320 are in contact with each other, and the contact surface between them is visible to an observer in a cross-sectional view. Similarly, the organic encapsulation layer 320 and the second inorganic encapsulation layer 330 are in contact with each other, and the contact surface between them is visible to an observer in a cross-sectional view.

[0100] Despite Figure 9 The text describes substrate 100 as comprising a polymer resin, but... Figure 9 The substrate 100 shown may optionally include a reference. Figure 4 The glass material described.

[0101] Figures 10A to 10D This is a diagram representing an MPCD based on a viewpoint θ according to an exemplary embodiment of the present disclosure. Figure 10E and Figure 10F This is a diagram representing the MPCD based on the perspective θ of the comparative example.

[0102] Figure 10A The results of MPCD based on viewing angle θ after manufacturing two hundred samples are shown. The first inorganic encapsulation layer 310 includes a silicon oxynitride layer with a refractive index n1 of about 1.77 and a thickness T of about 1100 nm, and the auxiliary layer 315 includes a silicon oxynitride layer with a refractive index n3 of about 1.62 and a thickness t of about 70 nm.

[0103] Figure 10B The results of MPCD based on viewing angle θ after manufacturing two hundred samples are shown. The first inorganic encapsulation layer 310 includes a silicon oxynitride layer having a refractive index n1 of about 1.77 and a thickness T of about 1170 nm, and the auxiliary layer 315 includes a silicon oxynitride layer having a refractive index n3 of about 1.62 and a thickness t of about 70 nm.

[0104] Figure 10C The results of MPCD based on viewing angle θ after manufacturing two hundred samples are shown. The first inorganic encapsulation layer 310 includes a silicon oxynitride layer having a refractive index n1 of about 1.77 and a thickness T of about 900 nm, and the auxiliary layer 315 includes a silicon oxynitride layer having a refractive index n3 of about 1.62 and a thickness t of about 70 nm.

[0105] Figure 10D The results of MPCD based on viewing angle θ after manufacturing two hundred samples are shown. The first inorganic encapsulation layer 310 includes a silicon oxynitride layer with a refractive index n1 of about 1.77 and a thickness T of about 1100 nm, and the auxiliary layer 315 includes a silicon oxynitride layer with a refractive index n3 of about 1.62 and a thickness t of about 40 nm.

[0106] Figure 10E This indicates the MPCD results based on the viewing angle θ after manufacturing two hundred samples, wherein the first inorganic encapsulation layer 310 includes a silicon oxynitride layer having a refractive index n1 of approximately 1.77 and a thickness T of approximately 1100 nm, and the auxiliary layer 315 includes a silicon oxynitride layer having a refractive index n3 of approximately 1.62 and a thickness t of approximately 100 nm.

[0107] Figure 10F This indicates the MPCD results based on the viewing angle θ after manufacturing two hundred samples, wherein the first inorganic encapsulation layer 310 includes a silicon oxynitride layer having a refractive index n1 of approximately 1.77 and a thickness T of approximately 1200 nm, and the auxiliary layer 315 is absent.

[0108] The information for each sample is summarized in Table 1 below.

[0109] Table 1

[0110] Reference Figures 10A to 10D as well as Figure 10E and Figure 10F It was found that when the thickness t of the auxiliary layer 315 was 100 nm or when the auxiliary layer 315 was absent, a reddish image was observed from the surface of the display device at a viewing angle of 30°. It was found that in all embodiments where the thickness range of the auxiliary layer 315 met the above conditions, the reddish problem was resolved.

[0111] The display device according to exemplary embodiments of the present disclosure can prevent chromatic aberration of light emitted from the display element and encapsulate the display element to prevent it from being affected by external impurities, while minimizing the thickness of the display device. However, the scope of the present disclosure is not limited to these effects.

[0112] It should be understood that the embodiments described herein are to be considered in a descriptive sense, and various modifications are possible within the spirit and scope of this disclosure. It should be understood that features and properties shown and described with respect to any one of the accompanying drawings may be mixed and matched with features and properties shown and described with respect to any other accompanying drawings.

Claims

1. A display device, comprising: substrate; Display elements are located above the substrate; A first inorganic encapsulation layer is placed above the display element. The first inorganic encapsulation layer comprises silicon oxynitride and has a thickness in the range of 600 nm to 2200 nm. An auxiliary layer, located above the first inorganic encapsulation layer, comprises an inorganic insulating material and has a thickness greater than or equal to 30 nm and less than 100 nm, wherein the refractive index of the auxiliary layer is less than the refractive index of the first inorganic encapsulation layer; The bottom layer, above the auxiliary layer, includes an oxygen-rich silicon oxynitride layer; An organic encapsulation layer is placed above the underlying layer; and The second inorganic encapsulation layer is located above the organic encapsulation layer.

2. The display device according to claim 1, wherein, The auxiliary layer is in direct contact with the first inorganic encapsulation layer, thus creating an interface between the auxiliary layer and the first inorganic encapsulation layer. The bottom layer is in direct contact with the auxiliary layer, thus creating an interface between the bottom layer and the auxiliary layer. The organic encapsulation layer is in direct contact with the underlying layer, thus creating an interface between the organic encapsulation layer and the underlying layer.

3. The display device according to claim 2, wherein, The refractive index 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 is the refractive index of the first inorganic encapsulation layer, n2 is the refractive index of the organic encapsulation layer, n3 is the refractive index of the auxiliary layer, min(n1, n2) is the minimum of n1 and n2, and |n2-n1| is the absolute value of the difference between n2 and n1.

4. The display device according to claim 2, wherein, The inorganic insulating material of the auxiliary layer includes silicon oxynitride.

5. The display device according to claim 1, wherein, The second inorganic encapsulation layer comprises silicon oxide, silicon nitride, or silicon oxynitride.

6. The display device according to claim 5, wherein, The number of elements contained in the second inorganic encapsulation layer is different from the number of elements contained in the first inorganic encapsulation layer.

7. The display device according to claim 1, wherein, The refractive index of the auxiliary layer is in the range of 1.57 to 1.7 to reduce the reddish image problem when viewing the display device in an tilted direction.

8. The display device according to claim 7, wherein, The refractive index of the bottom layer is less than the refractive index of the auxiliary layer and the refractive index of the first inorganic encapsulation layer.

9. The display device according to claim 8, wherein, The refractive index of the underlying layer is approximately 1.

52.

10. The display device according to claim 1, wherein, The thickness of the bottom layer is less than the thickness of the first inorganic encapsulation layer.

11. The display device according to claim 1, wherein, The display device further includes a lithium fluoride layer between the display element and the first inorganic encapsulation layer.

12. A display device, comprising: substrate; Display elements are located above the substrate; A first inorganic encapsulation layer is placed above the display element. The first inorganic encapsulation layer comprises silicon oxynitride and has a thickness in the range of 600 nm to 2200 nm. An auxiliary layer, located above the first inorganic encapsulation layer, comprises an inorganic insulating material and has a thickness greater than or equal to 30 nm and less than 100 nm, wherein the refractive index of the auxiliary layer is less than the refractive index of the first inorganic encapsulation layer; The bottom layer, above the auxiliary layer, includes an oxygen-rich silicon oxynitride layer, wherein the refractive index of the bottom layer is less than the refractive index of the auxiliary layer and the refractive index of the first inorganic encapsulation layer; An organic encapsulation layer is placed above the underlying layer; and The second inorganic encapsulation layer is located above the organic encapsulation layer.

13. The display device according to claim 12, wherein, The auxiliary layer is in direct contact with the first inorganic encapsulation layer, thus creating an interface between the auxiliary layer and the first inorganic encapsulation layer. The bottom layer is in direct contact with the auxiliary layer, thus creating an interface between the bottom layer and the auxiliary layer. The organic encapsulation layer is in direct contact with the underlying layer, thus creating an interface between the organic encapsulation layer and the underlying layer.

14. The display device according to claim 13, wherein, The inorganic insulating material of the auxiliary layer includes silicon oxynitride.

15. The display device according to claim 12, wherein, The refractive index 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 is the refractive index of the first inorganic encapsulation layer, n2 is the refractive index of the organic encapsulation layer, n3 is the refractive index of the auxiliary layer, min(n1, n2) is the minimum of n1 and n2, and |n2-n1| is the absolute value of the difference between n2 and n1.

16. The display device according to claim 12, wherein, The second inorganic encapsulation layer comprises silicon nitride.

17. The display device according to claim 12, wherein, The refractive index of the auxiliary layer is in the range of 1.57 to 1.7 to reduce the reddish image problem when viewing the display device in an tilted direction.

18. The display device according to claim 17, wherein, The refractive index of the underlying layer is approximately 1.

52.

19. The display device according to claim 12, wherein, The thickness of the bottom layer is less than the thickness of the first inorganic encapsulation layer.

20. The display device according to claim 12, wherein, The display device further includes a lithium fluoride layer between the display element and the first inorganic encapsulation layer.

21. A method for manufacturing a display device, wherein, The manufacturing method includes: A display element is formed on top of the substrate; A first inorganic encapsulation layer is formed above the display element, the inorganic encapsulation layer comprising silicon oxynitride and having a thickness in the range of 600 nm to 2200 nm; An auxiliary layer is formed above the first inorganic encapsulation layer. The auxiliary layer contains an inorganic insulating material and has a thickness greater than or equal to 30 nm and less than 100 nm, wherein the refractive index of the auxiliary layer is less than the refractive index of the first inorganic encapsulation layer. An underlayer is formed above the auxiliary layer, the underlayer comprising an oxygen-rich silicon oxynitride layer; An organic encapsulation layer is formed on top of the underlying layer; and A second inorganic encapsulation layer is formed on top of the organic encapsulation layer.

22. The manufacturing method according to claim 21, wherein, The auxiliary layer is in direct contact with the first inorganic encapsulation layer, thus creating an interface between the auxiliary layer and the first inorganic encapsulation layer. The bottom layer is in direct contact with the auxiliary layer, thus creating an interface between the bottom layer and the auxiliary layer. The organic encapsulation layer is in direct contact with the underlying layer, thus creating an interface between the organic encapsulation layer and the underlying layer.

23. The manufacturing method according to claim 22, wherein, The refractive index 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 is the refractive index of the first inorganic encapsulation layer, n2 is the refractive index of the organic encapsulation layer, n3 is the refractive index of the auxiliary layer, min(n1, n2) is the minimum of n1 and n2, and |n2-n1| is the absolute value of the difference between n2 and n1.

24. The manufacturing method according to claim 22, wherein, The inorganic insulating material of the auxiliary layer includes silicon oxynitride.

25. The manufacturing method according to claim 21, wherein, The second inorganic encapsulation layer comprises silicon oxide, silicon nitride, or silicon oxynitride.

26. The manufacturing method according to claim 25, wherein, The number of elements contained in the second inorganic encapsulation layer is different from the number of elements contained in the first inorganic encapsulation layer.

27. The manufacturing method according to claim 21, wherein, Forming the organic encapsulation layer includes coating a monomer and curing the monomer, wherein, during the formation of the organic encapsulation layer, the underlying layer controls the materials constituting the organic encapsulation layer.

28. The manufacturing method according to claim 21, wherein, The refractive index of the auxiliary layer is in the range of 1.57 to 1.7 to reduce the reddish image problem when viewing the display device in an tilted direction.

29. The manufacturing method according to claim 28, wherein, The refractive index of the bottom layer is less than the refractive index of the auxiliary layer and the refractive index of the first inorganic encapsulation layer.

30. The manufacturing method according to claim 29, wherein, The refractive index of the underlying layer is approximately 1.

52.

31. The manufacturing method according to claim 21, wherein, The thickness of the bottom layer is less than the thickness of the first inorganic encapsulation layer.

32. The manufacturing method according to claim 21, wherein, The manufacturing method further includes: A lithium fluoride layer is formed between the display element and the first inorganic encapsulation layer.

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