Display device

Abstract

A display device according to an embodiment includes: a substrate; the display layer is located on the substrate; the substrate layer is positioned on the display layer; the hard coating layer is positioned on the substrate layer; and a low refractive index layer over the hard coating layer, the base layer including an ultraviolet absorber.

Description

Technical Field

[0001] The disclosed embodiments relate to display devices. Background Technology

[0002] Typical examples of display devices include liquid crystal displays and organic light emitting displays.

[0003] In particular, unlike liquid crystal displays, organic light-emitting displays do not require a backlight unit and can minimize thickness. Therefore, research is currently being conducted on flexible, stretchable, foldable, bendable, or rollable organic light-emitting displays.

[0004] These flexible display devices feature flexible windows on the display panel that displays images, thus protecting the display device while ensuring its flexibility. Summary of the Invention

[0005] Technical issues

[0006] The embodiments are used to protect the light-emitting element layer from ultraviolet radiation.

[0007] Solution

[0008] The display device according to an embodiment includes: a substrate; a display layer disposed on the substrate; a base layer disposed on the display layer; a hard coating layer disposed on the base layer; and a low refractive index layer disposed on the hard coating layer, the base layer comprising an ultraviolet absorber.

[0009] The low-refractive-index layer may contain dodecafluoroheptyl acrylate.

[0010] The ultraviolet absorber may contain at least one of methylimine compounds, cyanoacrylates, and benzotriazoles.

[0011] The thickness of the low-refractive-index layer can be approximately 80 nm to approximately 120 nm.

[0012] The base layer may contain polyethylene terephthalate.

[0013] The ultraviolet absorber may contain a mixture of methylimine compounds and benzotriazole in a ratio of 0.8 to 1.2: 2 to 3.

[0014] The base layer may contain a mixture of the polyethylene terephthalate, the methylimine compound, and benzotriazole in a ratio of 0.8–1.2:1.2–0.8.

[0015] The ultraviolet absorber may contain a mixture of a methylimine compound and a cyanoacrylate in a ratio of 0.8 to 1.2: 1.6 to 2.4.

[0016] The base layer may comprise a mixture of the polyethylene terephthalate, the methylimine compound, and cyanoacrylate in a ratio of 0.8–1.2:1.2–0.8.

[0017] A display device according to one embodiment includes: a substrate; a display layer disposed on the substrate; a base layer disposed on the display layer; a hard coating layer disposed on the base layer; and a low refractive index layer disposed on the hard coating layer, the low refractive index layer comprising an ultraviolet absorber.

[0018] The thickness of the low-refractive-index layer can be approximately 80 nm to approximately 120 nm.

[0019] The thickness of the base layer can be from about 40 μm to about 90 μm, and the thickness of the hard coating layer can be from about 3 μm to about 7 μm.

[0020] The low-refractive-index layer may contain a random silsesquioxane monomer with 12 perfluoroalkyl groups and 6 reactive groups.

[0021] Each of the 12 perfluoroalkyl groups can be C3F7, C4F9, and C5F7. 11 Any one of them.

[0022] The ultraviolet absorber may contain at least one of methylimine compounds, cyanoacrylates, and benzotriazoles.

[0023] The base layer may contain polyethylene terephthalate.

[0024] The ultraviolet absorber may contain a mixture of a methylimine compound and a cyanoacrylate in a ratio of 0.8 to 1.2: 1.6 to 2.4.

[0025] The low refractive index layer may contain a mixture of the silsesquioxane monomer and the ultraviolet absorber in a ratio of 5.4–9.6:1.6–2.4.

[0026] The ultraviolet absorber may contain a mixture of methylimine compounds and benzotriazole in a ratio of 0.8 to 1.2: 2 to 3.

[0027] The low refractive index layer may contain a mixture of the silsesquioxane monomer and the ultraviolet absorber in a ratio of 5.4–9.6:1.6–2.4.

[0028] Beneficial effects

[0029] According to an embodiment, the window of the display device contains an ultraviolet absorber, thereby protecting the light-emitting element layer from ultraviolet radiation. Attached Figure Description

[0030] Figure 1 This is a schematic perspective view showing the usage state of a display device according to an embodiment.

[0031] Figure 2 This is an exploded perspective view of a display device according to one embodiment.

[0032] Figure 3 It is an illustrative representation of the basis and Figure 2 Perspective views of display devices in different embodiments.

[0033] Figure 4 This is a schematic cross-sectional view of a portion of a display device according to one embodiment.

[0034] Figure 5 This is a schematic cross-sectional view of a portion of a display device according to another embodiment.

[0035] Figure 6 This is a schematic cross-sectional view of a portion of a display device according to a comparative example.

[0036] Figure 7 This is a schematic cross-sectional view of a portion of a display device according to another comparative example.

[0037] Figure 8 It is an illustrative representation of the basis and Figure 7 A cross-sectional view of a portion of a display device of different comparative examples.

[0038] Figure 9 This is a schematic diagram illustrating the manufacturing process of the film layer and hard coating of a display device.

[0039] Figure 10 It is shown Figure 4 The diagram shows the manufacturing process of the low-refractive-index layer of the display panel.

[0040] Figure 11 It is shown Figure 5 The diagram shows the manufacturing process of the low-refractive-index layer of the display panel.

[0041] Figure 12 It is shown Figure 4The graph shown is a result of the transmission spectral analysis of the display panel.

[0042] Figure 13 It is shown Figure 4 The graph shown is a result of the reflectance spectral analysis of the display panel.

[0043] Figure 14 It is shown Figure 5 The graphs show the results of ultraviolet and visible light spectroscopic analysis of the display panel.

[0044] Figure 15 It is shown Figure 5 The graph shown shows the surface analysis results of the display panel performed by X-ray photoelectron spectroscopy.

[0045] Explanation of reference numerals in the attached figures

[0046] U-FLM: A membrane containing ultraviolet absorbers

[0047] U-LR: Low-refractive-index layer containing ultraviolet absorbers

[0048] FLM: membrane layer

[0049] HC: Hard coating

[0050] LR: Low Refractive Index Layer

[0051] CW: Coverage Window

[0052] 1000: Display device

[0053] ENC: Thin Film Encapsulation Layer Detailed Implementation

[0054] Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings, so as to enable those skilled in the art to readily practice the invention. The present invention can be implemented in various different forms and is not limited to the embodiments described herein.

[0055] To clearly illustrate the invention, irrelevant parts have been omitted, and the same figures are used throughout the specification to show the same or similar components.

[0056] Furthermore, since the dimensions and / or thicknesses of the structures shown in the accompanying drawings are arbitrary for ease of explanation, the present invention is not limited to the illustrated cases. In the drawings, the thicknesses are enlarged to clearly show multiple layers and regions. Additionally, the thicknesses of some layers and regions are exaggerated in the drawings for ease of explanation.

[0057] Furthermore, when it is stated that a layer, membrane, region, plate, or other part is "above" or "on" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when it is stated that any part is "directly above" another part, this means that there is no other part in between. In addition, "above" or "on" the part that serves as a reference means being located above or below the part that serves as a reference, and does not necessarily mean being "above" or "on" the side opposite to the direction of gravity.

[0058] Furthermore, throughout the specification, when it is stated that any part "includes" any constituent element, unless specifically stated to the contrary, this means that other constituent elements may also be included, rather than excluding other constituent elements.

[0059] Furthermore, throughout the instruction manual, when it is described as "on a plane," it refers to the view of the target portion from above, and when it is described as "on a cross section," it refers to the view of the cross section of the target portion that is perpendicularly cut from the side.

[0060] The following is through Figure 1 and Figure 2 Observe the structure of the schematic display device. Figure 1 This is a schematic perspective view showing the usage state of a display device according to an embodiment. Figure 2 This is an exploded perspective view of a display device according to one embodiment.

[0061] Reference Figure 1According to one embodiment, the display device 1000 is a device for displaying dynamic or static images, and can be used as a display screen for various products such as mobile phones, smartphones, tablet PCs, mobile communication terminals, electronic manuals, e-books, portable multimedia players (PMPs), navigators, ultra-mobile PCs (UMPCs), televisions, laptops, monitors, billboards, and Internet of Things (IoT) devices. Furthermore, according to one embodiment, the display device 1000 can be used in wearable devices such as smartwatches, watch phones, glasses displays, and head-mounted displays (HMDs). Furthermore, the display device 1000 according to one embodiment can be used as a central information display (CID) arranged in the dashboard and center fascia or instrument panel of a car, as an interior mirror display replacing the rearview mirror of a car, or as a display arranged on the back of the front seats as an entertainment device for the rear seats of a car. For ease of explanation, Figure 1 The display device 1000 is shown being used as a smartphone.

[0062] The display device 1000 can display an image facing a third direction DR3 from a display surface parallel to each of the first direction DR1 and the second direction DR2. The display surface of the image can correspond to the front surface of the display device 1000 and the front surface of the overlay window CW. The image can include both moving images and still images.

[0063] In this embodiment, the front (or upper) and back (or lower) surfaces of each component are defined based on the orientation of the displayed image. The front and back surfaces can be opposite to each other on the third-direction DR3, and the normal direction of each of the front and back surfaces can be parallel to the third-direction DR3. The spacing between the front and back surfaces on the third-direction DR3 can correspond to the thickness of the display panel DP on the third-direction DR3.

[0064] According to one embodiment, the display device 1000 can sense user input applied from the outside (see [link]). Figure 1(The user's input can include various forms of external input such as a part of the user's body, light, heat, or pressure. In one embodiment, the user's input is shown as a hand applied to the front of the user. However, the invention is not limited thereto. The user's input can be provided in various forms, and, depending on the structure of the display device 1000, the display device 1000 can also sense user input applied to the side or back of the display device 1000.)

[0065] Reference Figure 1 and Figure 2 The display device 1000 may include a cover window (CW), a housing (HM), a display panel (DP), and optical elements (ES). In one embodiment, the cover window (CW) and the housing (HM) may be combined to form the appearance of the display device 1000.

[0066] Covering windows (CWs) may include insulating panels. For example, covering windows (CWs) may be made of glass, plastic, or a combination thereof.

[0067] The front of the cover window CW can define the front of the display device 1000. The transmissive region TA can be an optically transparent region. For example, the transmissive region TA can be a region with a visible light transmittance of about 90% or more.

[0068] The blocking region BBA can define the shape of the transmitting region TA. The blocking region BBA can be adjacent to and surround the transmitting region TA. Compared to the transmitting region TA, the blocking region BBA can be a region with relatively low light transmittance.

[0069] The display panel DP may include pixels PX for displaying images and a driving unit 50, wherein the pixels PX are located within the display area DA and the component area EA. The display panel DP may include a front surface having the display area DA and a non-display area PA. In one embodiment, the display area DA and the component area EA may be areas that include pixels PX for displaying images, and simultaneously, a touch sensor is provided on the upper side of the third-direction DR3 of the pixels PX for sensing external input.

[0070] The transmissive region TA of the overlay window CW can at least partially overlap with the display region DA and component region EA of the display panel DP. For example, the transmissive region TA can overlap with the front of the display region DA and component region EA, or overlap with at least a portion of the display region DA and component region EA. Therefore, a user can visually identify an image through the transmissive region TA, or provide external input based on the image. However, the invention is not limited thereto. For example, the area for displaying the image and the area for sensing external input can also be separated from each other.

[0071] The non-display area PA of the display panel DP may overlap at least partially with the blocking area BBA of the cover window CW. The non-display area PA may be the area covered by the blocking area BBA. The non-display area PA may be adjacent to and surround the display area DA. The non-display area PA may not display an image and may house drive circuitry or drive wiring for driving the display area DA. The non-display area PA may include a first non-display area PA1 located outside the display area DA and a second non-display area PA2 including a drive section 50, connecting wiring, and a bending area. Figure 2 In one embodiment, the first non-display area PA1 is located on three sides of the display area DA, and the second non-display area PA2 is located on the remaining side of the display area DA.

[0072] A portion of the non-display area PA of the display panel DP can be bent. In this case, a portion of the non-display area PA faces the back of the display device 1000, thereby reducing the obstruction area BBA visible from the front of the display device 1000. Figure 2 In this process, the second non-display area PA2 can be bent and positioned on the back of the display area DA before assembly.

[0073] Furthermore, the component area EA of the display panel DP may include a first component area EA1 and a second component area EA2. The first component area EA1 and the second component area EA2 may be at least partially surrounded by the display area DA. Although shown as a form where the first component area EA1 and the second component area EA2 are spaced apart from each other, this is not a limitation, and they may also be at least partially connected. The first component area EA1 and the second component area EA2 may have optical elements utilizing infrared light, visible light, or sound, etc., arranged beneath them (see reference). Figure 2 The region of ES (hereinafter also referred to as a component).

[0074] Multiple light-emitting diodes (LEDs) and multiple pixel circuit sections for generating and transmitting light-emitting current in each of the LEDs are formed in the display area DA (hereinafter also referred to as the main display area) and the component area EA. Here, one LED and one pixel circuit section are referred to as a pixel PX. In the display area DA and the component area EA, one pixel circuit section and one LED can be formed in a one-to-one ratio.

[0075] The first component region EA1 may include a transmissive portion capable of transmitting light and / or sound and a display layer comprising a plurality of pixels. The transmissive portion is located between adjacent pixels and is composed of a layer capable of transmitting light and / or sound. The transmissive portion may be located between adjacent pixels, and according to an embodiment, a light-blocking layer or the like may overlap with the first component region EA1. The number of pixels per unit area (hereinafter, also referred to as resolution) of the pixels included in the display region DA (hereinafter, also referred to as conventional pixels) and the number of pixels per unit area of ​​the pixels included in the first component region EA1 (hereinafter, also referred to as first component pixels) may be the same.

[0076] The second component region EA2 includes a region consisting of a transparent layer capable of transmitting light (hereinafter also referred to as the light-transmitting region). The light-transmitting region lacks a conductive or semiconductor layer. It can have a non-light-shielding structure by including openings in a layer containing a light-shielding material (e.g., a pixel defining layer and / or a light-shielding component) that overlap with the position corresponding to the second component region EA2. The number of pixels per unit area of ​​the pixels included in the second component region EA2 (hereinafter also referred to as the second component pixel) can be less than the number of pixels per unit area of ​​conventional pixels included in the display region DA. As a result, the resolution of the second component pixel can be lower than that of the conventional pixel.

[0077] The second non-display area PA2 may include a bend. The display area DA and the first non-display area PA1 may be in a flat state, substantially parallel to the plane defined by the first direction DR1 and the second direction DR2. One side of the second non-display area PA2 may extend from the flat state, pass through the bend, and then become flat again. As a result, at least a portion of the second non-display area PA2 can be bent and assembled to be located on the back side of the display area DA. At least a portion of the second non-display area PA2 overlaps with the display area DA in the plane during assembly, thus reducing the obstruction area BBA of the display device 1000.

[0078] The driver unit 50 can be mounted on the second non-display area PA2, and can be mounted on the curved portion or located at one of the two sides of the curved portion. The driver unit 50 can be provided in chip form.

[0079] The driving unit 50 can be electrically connected to the display area DA and the component area EA to transmit electrical signals to the pixels PX in the display area DA and the component area EA. For example, the driving unit 50 can provide data signals to the pixels PX arranged in the display area DA. Alternatively, the driving unit 50 can include touch driving circuitry and can also be electrically connected to touch sensors arranged in the display area DA and / or the component area EA. On the other hand, the driving unit 50 can also be designed to include various circuits other than those described above or to provide various electrical signals to the display area DA.

[0080] On the other hand, a pad portion may be provided at the end of the second non-display area PA2 of the display device 1000, and this pad portion can be electrically connected to a flexible printed circuit board (FPCB) including a driver chip. Here, the driver chip located on the flexible printed circuit board may include various drive circuits for driving the display device 1000 or connectors for power supply, etc. According to an embodiment, a rigid printed circuit board (PCB) can be used instead of a flexible printed circuit board.

[0081] Optical element ES can be arranged below display panel DP. Optical element ES may include a first optical element ES1 overlapping with the first component region EA1 and a second optical element ES2 overlapping with the second component region EA2. The first optical element ES1 may also use infrared light, in which case a light-blocking layer such as a light-blocking component may overlap with the first component region EA1.

[0082] The first optical element ES1 can be an electronic component that utilizes light or sound. For example, the first optical element ES1 can be a sensor that receives and utilizes light, such as an infrared sensor; a sensor that outputs and senses light or sound to measure distance or identify fingerprints; a small lamp that outputs light; or a speaker that outputs sound. In the case of an electronic component that utilizes light, various wavelengths of light, such as visible light, infrared light, and ultraviolet light, can certainly be used.

[0083] The second optical element ES2 can be at least one of a camera, an infrared camera (IR camera), a dot projector, an infrared illuminator (IR illuminator), and a time-of-flight sensor (ToF sensor).

[0084] The housing HM can be combined with the cover window CW. The cover window CW can be positioned in front of the housing HM. The housing HM can be combined with the cover window CW to provide a predetermined receiving space. The display panel DP and optical components ES can be housed in the predetermined receiving space provided between the housing HM and the cover window CW.

[0085] The housing HM can contain a material with relatively high rigidity. For example, the housing HM can include glass, plastic, or metal, or include multiple frames and / or plates composed of a combination of these. The housing HM can stably protect the structure of the display device 1000 housed within the internal space from external impacts.

[0086] The following is through Figure 3Observe the structure of the display device 1000 according to another embodiment. Figure 3 This is a schematic perspective view of a light-emitting display device according to one embodiment. Descriptions of structures with the same constituent elements as described above will be omitted. Figure 3 The embodiment shows a foldable display device with a structure in which the display device 1000 is folded by a folding axis FAX.

[0087] Reference Figure 3 In one embodiment, the display device 1000 may be a foldable display device. The display device 1000 may fold outward or inward with respect to the folding axis FAX. When folded outward with respect to the folding axis FAX, the display surface of the display device 1000 may be located on the outer side of the third direction DR3 to display images in both directions. When folded inward with respect to the folding axis FAX, the display surface may not be visible from the outside.

[0088] In one embodiment, the display device 1000 may include a display area DA, a component area EA, and a non-display area PA. The display area DA may be divided into a first-first display area DA1-1, a first-second display area DA1-2, and a folding area FA. The first-first display area DA1-1 and the first-second display area DA1-2 may be located on the left and right sides respectively with respect to the folding axis FAX (or, the center), and the folding area FA may be located between the first-first display area DA1-1 and the first-second display area DA1-2. In this case, if folded outward with respect to the folding axis FAX, the first-first display area DA1-1 and the first-second display area DA1-2 may be located on both sides of the third direction DR3 and display images in both directions. Furthermore, if folded inward with respect to the folding axis FAX, the first-first display area DA1-1 and the first-second display area DA1-2 may not be visible from the outside.

[0089] The following is through Figures 4 to 5 Observe the window structure of the display device applicable to the embodiments of the invention. Figure 4 This is a schematic cross-sectional view of a portion of a display device according to one embodiment. Figure 5 This is a schematic cross-sectional view of a portion of a display device according to another embodiment.

[0090] First, refer to Figure 4 Observe display devices including U-FLM films containing ultraviolet absorbers.

[0091] The display device according to the embodiment may include a substrate (not shown), a display layer ED on the substrate, a thin film encapsulation layer ENC on the display layer ED, and a cover window CW above the thin film encapsulation layer ENC.

[0092] The substrate can be a transparent substrate and can be formed of a flexible material such as a polymer film.

[0093] The display layer ED can be formed on a substrate. The display layer ED includes a component region on which optical elements such as thin-film transistors (TFTs) are formed and a light-emitting region on which a light-emitting layer is formed. The component region and the light-emitting region can exist separately or overlap.

[0094] The thin-film encapsulation layer ENC can be located above the display layer ED. The thin-film encapsulation layer ENC can be formed from a composite film comprising both inorganic and organic films. In one embodiment, it includes a structure in which a third inorganic encapsulation layer EIL3, a second organic encapsulation layer EOL2, a second inorganic encapsulation layer EIL2, a first organic encapsulation layer EOL1, and a first inorganic encapsulation layer EIL1 are sequentially present. At least one of the aforementioned inorganic and organic encapsulation layers can be omitted.

[0095] The thin-film encapsulation layer (ENC) can be integrally formed to overlap the front of the display area, or it can be partially disposed on the non-display area. The ENC protects the display area from external gases or moisture.

[0096] The cover window (CW) is located above the thin-film encapsulation layer (ENC). The cover window (CW) may include a single component or multiple components. This embodiment includes multiple window components, including a film layer (also known as a base layer) containing an ultraviolet absorber (U-FLM), a hard coating layer (HC) on the U-FLM, and a low-refractive-index layer (LR) on the HC. These components protect the cover window (CW) from scratches, abrasions, and other damage. However, the structure of the cover window (CW) is not necessarily limited to this; it may include other structures or a protective film on its lower surface.

[0097] The following section examines the U-FLM film containing an ultraviolet absorber, which is included in the cover window CW. The film and ultraviolet absorber of the U-FLM film containing the ultraviolet absorber will be described separately below.

[0098] Ultraviolet absorber-containing membranes (U-FLM) include films formed from transparent materials. For example, the film can be formed to include glass or plastic. When including a film formed from plastic, the cover window (CW) can have flexible properties. Suitable plastics for the film should possess excellent transparency, mechanical strength, thermal stability, moisture resistance, isotropy, etc. While not particularly limited to this, examples of plastics to which this can be applied include polyethylene terephthalate (PET), polyacrylate, polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), polyurethane (PU), polyimide (PI), polycarbonate (PC), polyvinylidene chloride, polyvinylidene difluoride (PVDF), polystyrene, ethylene vinyl alcohol copolymer, polyethersulfone (PES), polyetherimide (PEI), polyphenylene sulfide (PPS), polyarylate, triacetylcellulose (TAC), cellulose acetate propionate (CAP), and others. The U-FLM containing ultraviolet absorbers may include more than one of the listed plastic materials.

[0099] The cover window CW according to an embodiment of the present invention includes a film layer U-FLM containing an ultraviolet absorber. The film layer U-FLM containing the ultraviolet absorber includes polyethylene terephthalate (PET) represented by chemical formula 1.

[0100] [Chemical Formula 1]

[0101]

[0102] The thickness of the U-FLM film containing ultraviolet absorbers can range from about 40 μm to about 90 μm.

[0103] The ultraviolet absorber contained in the U-FLM film of the present invention blocks ultraviolet A (UVA) rays, particularly long-wavelength UVA rays in the range of 315 nm to 400 nm. Specifically, the light transmittance in the ultraviolet region at a wavelength of 370 nm is maintained at approximately 0%. This suppresses or prevents ultraviolet degradation of optical elements included in the display layer ED, thereby improving the durability and stability of the display layer ED.

[0104] The substances suitable for use as UV absorbers are not particularly limited. Examples include UV absorbers with various skeleton structures such as benzotriazole compounds, cyanoacrylate compounds, triazine compounds, benzophenone compounds, benzoxazinone compounds, salicylic acid compounds, and benzoxazine compounds. One or more of these can be used in combination. When two or more UV absorbers are used together, they can be UV absorbers with the same skeleton structure or UV absorbers with different skeleton structures.

[0105] In addition to ultraviolet absorbers, the U-FLM film containing ultraviolet absorbers may also contain pigments that function as ultraviolet absorbers. The pigments are not particularly limited; examples include pigments and dyes, which can be used alone or in combination. As pigments, there are no particular limitations. For example, examples include azomethince pigments such as copper methimide yellow, phthalocyanine pigments such as phthalocyanine green and phthalocyanine blue, fast yellow, diazo yellow, condensed azo yellow, benzimidazole ketone yellow, dinitroaniline orange, benzimidazole orange, toluidine red, permanent carmine, permanent red, naphthol red, condensed azo red, dinitroaniline carmine, dinitroaniline brown, etc., anthraquinone pigments such as anthraquinone yellow and anthraquinone red, quinophthalone pigments such as quinophthalone yellow, isoindoline pigments such as isoindoline yellow, nitroso pigments such as dioxin nickel yellow, and perinone orange. Organic pigments including pyrenones such as orange, quinacridone fuchsin, quinacridone brownish-red, quinacridone deep red, quinacridone red, perylene red, perylene brownish-red, pyrrolopyrrole pigments such as diketopyrrolopyrrole red, dioxazine violet, carbon black, lamp black, furnace black, ivory black, graphite, fullerene, chromate pigments such as aluminum chrome yellow and molybdenum chrome orange, cadmium yellow, lithium cadmium yellow, cadmium orange, lithium cadmium orange, silver vermilion, cadmium... Sulfide pigments such as red, lithium cadmium red, and sulfide; ochre, titanium yellow, titanium barium nickel yellow, aggregates, lead oxide, amber, iron oxide brown, zinc iron chromium brown, chromium oxide, cobalt green, cobalt chromium green, titanium cobalt green, cobalt blue, cerium blue, cobalt aluminum chromium blue, iron black, manganese ferrite black, cobalt ferrite black, copper chromium black, copper chromium manganese black, etc.; hydroxide pigments such as deep emerald green; ferrocyanide pigments such as magenta blue; silicate pigments such as super blue; phosphate pigments such as cobalt violet and mineral violet; and other inorganic pigments (e.g., cadmium sulfide, cadmium selenide, etc.).

[0106] The ultraviolet absorber included in the display device of this embodiment may be a mixture of a methylimine compound represented by chemical formula 2 and a benzotriazole represented by chemical formula 3. As a component of the methylimine compound's group, R... 1 The case may include propyl, R 2 The case can include ethoxy groups, R 3The group may include alkoxycarbonyl groups. In the examples, the ratio of the methylimine compound to the benzotriazole may be 0.8–1.2:2–3. In experiments using an ultraviolet absorber containing this ratio, the antireflective function of the low-refractive-index layer was maintained while keeping the light transmittance in the ultraviolet region at 370 nm at approximately 0%.

[0107] [Chemical Formula 2]

[0108]

[0109] [Chemical Formula 3]

[0110]

[0111] In another embodiment, the ultraviolet absorber may comprise a mixture of a methylimine compound represented by Formula 2 and a cyanoacrylate represented by Formula 4. In this embodiment, the ratio of the methylimine compound to the cyanoacrylate may be 0.8–1.2:1.6–2.4. In embodiments containing this ratio of ultraviolet absorber, the U-FLM film containing the ultraviolet absorber provides ultraviolet blocking functionality while maintaining the anti-reflective function of the low-refractive-index layer.

[0112] [Chemical Formula 4]

[0113]

[0114] In embodiments of the present invention, the ratio of polyethylene terephthalate film and ultraviolet absorber in the U-FLM film containing ultraviolet absorber may also include a ratio of 0.8 to 1.2: 1.2 to 0.8. This is a ratio used to maintain the optical properties of the film.

[0115] The hard coating HC is placed on the film layer U-FLM containing ultraviolet absorbers to improve the hardness of the cover window CW.

[0116] In one embodiment, the hard coating HC may include an organic layer comprising an acrylate compound and / or an organic-inorganic composite layer. The organic layer may comprise an acrylate compound. The organic-inorganic composite layer may be a layer in which inorganic substances such as silicon dioxide, zirconium oxide, aluminum oxide, tantalum oxide, niobium oxide, and glass beads are dispersed in an organic substance such as an acrylate compound. In another embodiment, the hard coating HC may include a metal oxide layer. The metal oxide layer may comprise, but is not limited to, metal oxides such as titanium, aluminum, molybdenum, tantalum, copper, indium, tin, and tungsten.

[0117] The thickness of the hard coating HC can range from about 3 μm to about 7 μm.

[0118] A low-refractive-index layer LR exists above the hard coating HC. The low-refractive-index layer LR acts as an optical compensation layer, providing anti-reflective properties. Even though the UV absorber is contained within the UV absorber-containing film U-FLM, the anti-reflective function of the hard coating HC should be maintained.

[0119] As a component for forming the low refractive index layer (LR), examples include inorganic particles that have been surface-treated with fluorine compounds (hereinafter referred to as fluorinated inorganic particles). Suitable inorganic particles for fluorinated inorganic particles include those comprising elements selected from Si, Na, K, Ca, and Mg. As a preferred example, inorganic particles comprising compounds selected from silica particles (SiO2), alkali metal fluorides (NaF, KF, etc.), and alkaline earth metal fluorides (CaF2, MgF2, etc.) are preferred, with silica particles being particularly preferred when considering durability, refractive index, etc.

[0120] Suitable silica particles for use in fluorinated inorganic particles are hollow silica particles (silica particles with hollow interiors) or porous silica particles (silica particles with fine pores on the surface and inside). Examples include, but are not limited to, compositions comprising silsesquioxanes or compositions comprising silsesquioxanes and fillers.

[0121] As a method for surface treatment of silica particles with fluorine compounds, for example, dodecafluoroheptyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3,3-pentafluoropropyl (meth)acrylate, 2-perfluorobutylethyl (meth)acrylate, 3-perfluorobutyl-2-hydroxypropyl (meth)acrylate, 2-perfluorohexylethyl (meth)acrylate, 3-perfluorohexyl-2-hydroxypropyl (meth)acrylate, 2-perfluorooctylethyl (meth)acrylate, 3-perfluorooctyl-2-hydroxypropyl (meth)acrylate Compounds of acrylates, 2-perfluorodecylethyl(meth)acrylates, 2-perfluoro-3-methylbutylethyl(meth)acrylates, 3-perfluoro-3-methoxybutyl-2-hydroxypropyl(meth)acrylates, 2-perfluoro-5-methylhexylethyl(meth)acrylates, 3-perfluoro-5-methylhexyl-2-hydroxypropyl(meth)acrylates, 2-perfluoro-7-methyloctyl-2-hydroxypropyl(meth)acrylates, tetrafluoropropyl(meth)acrylates, octafluoropentyl(meth)acrylates, hexafluorononyl(meth)acrylates, hexafluorobutyl(meth)acrylates, etc.

[0122] The thickness of the low refractive index layer (LR) can range from approximately 80 μm to approximately 120 μm.

[0123] In embodiments of the present invention, the low refractive index layer LR comprises, for example, dodeca fluoroheptyl acrylate (DFHA, represented by formula 5).

[0124] [Chemical Formula 5]

[0125]

[0126] Reference Figure 5 The observation will focus on a display device comprising a low refractive index layer U-LR containing an ultraviolet absorber, and descriptions of structures with the same constituent elements as those described above will be omitted.

[0127] The cover window (CW) of the present invention includes a film layer (FLM) that does not contain ultraviolet absorbers. The film layer (FLM) may contain and include... Figure 4 The membrane in the U-FLM containing the ultraviolet absorber is made of the same material. In one embodiment, the FLM comprises polyethylene terephthalate (PET) represented by Formula 1.

[0128] The low-refractive-index layer U-LR containing the ultraviolet absorber may comprise a silsesquioxane monomer (hereinafter referred to as R-type SQ) with 12 perfluoroalkyl groups and 6 reactive groups, as represented by Formula 6. Each of the 12 perfluoroalkyl groups in the R-type SQ may comprise C3F7, C4F9, and C5F... 11 Any one of them.

[0129] [Chemical Formula 6]

[0130]

[0131] In embodiments of the present invention, the ratio of ultraviolet absorber to R-type SQ can be 1.6–2.4:5.4–9.6. In embodiments containing ultraviolet absorber of this ratio, the low refractive index layer U-LR containing ultraviolet absorber has both ultraviolet blocking and anti-reflection functions.

[0132] The preferred thickness of the low-refractive-index layer U-LR containing the ultraviolet absorber is approximately 80 nm to approximately 120 nm. In particular, when the thickness of the low-refractive-index layer U-LR containing the ultraviolet absorber is 100 nm or more, the efficiency and ultraviolet blocking effect of the low-refractive-index layer U-LR can be further improved, because the ratio of the ultraviolet absorber to the constituent material of the low-refractive-index layer U-LR containing the ultraviolet absorber, i.e., R-type SQ, can be easily adjusted.

[0133] The following is through Figures 6 to 8 Observe the structure of the display device based on the comparative example. Figure 6This is a schematic cross-sectional view of a portion of a display device according to a comparative example. Figure 7 This is a schematic cross-sectional view of a portion of a display device according to another comparative example. Figure 8 It is an illustrative representation of the basis and Figure 7 A cross-sectional view of a portion of a display device of different comparative examples.

[0134] Figure 6 The display panel does not contain any ultraviolet-absorbing materials. Therefore, the display panel may be damaged by long-wave ultraviolet A rays penetrating into the interior of the optical components.

[0135] Figure 7 The display panel has a structure that includes an ultraviolet-blocking film (UVF) above the thin-film encapsulation layer (ENC).

[0136] Ultraviolet blocking film (UVF) is a substance that can absorb ultraviolet light. For example, it can include organic compounds such as benzophenone, benzotriazole, salicylic acid, cyanoacrylate, oxanilide, resorcinol monobenzoate, and cinnamate.

[0137] When the ultraviolet blocking film UVF is located above the thin-film encapsulation layer ENC, compared with the embodiments of the present invention, there is a concern that the foldability of the flexible display is reduced due to the increased thickness of the display panel.

[0138] Figure 8 The display panel disperses substances capable of absorbing ultraviolet rays in a manner that is located within the display panel. Figure 6 The organic layers of the first organic encapsulation layer EOL1 and the second organic encapsulation layer EOL2 of the thin-film encapsulation layer ENC contain substances capable of absorbing ultraviolet light. Therefore, the thin-film encapsulation layer ENC includes a structure such as a first ultraviolet-blocking organic encapsulation layer U-EOL1 and a second ultraviolet-blocking organic encapsulation layer U-EOL2.

[0139] As ultraviolet-absorbing materials contained in the first ultraviolet-blocking organic encapsulation layer U-EOL1 and the second ultraviolet-blocking organic encapsulation layer U-EOL2, they may include, for example, compounds such as benzotriazole, benzophenone and salicylic acid.

[0140] However, in this case, the ultraviolet-absorbing material may react with organic molecules in the thin-film encapsulation layer ENC, thereby potentially weakening the encapsulation function of the thin-film encapsulation layer ENC compared to embodiments of the present invention.

[0141] The following is for reference Figures 9 to 15 The disclosure of the present invention can be specifically observed through comparative embodiments and comparative examples.

[0142] [Example 1]

[0143] pass Figure 9 Observe the manufacturing process of the film and hard coating. Figure 9 This is a schematic diagram illustrating the manufacturing process of the film layer and hard coating of a display device.

[0144] The composition of the functional groups of the methylimine compounds represented by chemical formula 2, used as ultraviolet absorbers, is as follows. In chemical formula 2, R... 1 It is propyl ([CH3CH2CH2]) n (n=1), R 2 It is an ethoxylated group ([CH3CH2O)). n (n=6), R 3 It is an alkoxycarbonyl group ([CH3COO)). n (n=2).

[0145] The ultraviolet absorber is formulated with a methylimine compound and benzotriazole (hereinafter referred to as ultraviolet absorber 1) in a ratio of 1:2.5. The formulated ultraviolet absorber 1 is then formulated with polyethylene terephthalate in a ratio of 1:1.

[0146] The compound is added to the extruder ET, then placed into the die-casting machine TD for molding, and then cooled using the cooling roller CR. The film is then passed through the pick-up machine PM and the winding machine WM to ensure that the film has a uniform thickness.

[0147] If the film is added to the slot extrusion coating (SD) equipment, the back roller (BR) rotates and applies a hard coating material, which is then dried to form a hard coating (HC).

[0148] pass Figure 10 We observed the manufacturing process of the low-refractive-index layer of the display panel. Figure 10 It is shown Figure 4 The diagram shows the manufacturing process of the low-refractive-index layer of the display panel.

[0149] If a film with a hard coating is placed into the first roller RL1 using a roller-to-roll process, then tensioning the first roller TR1, the second roller TR2, the third roller TR3, and the fourth roller TR4 allows the film to enter the main roller MR in a uniformly spread state. The film rotates above the main roller MR at a constant angular velocity α.

[0150] If the membrane is rotating while entering, the first valve VV1 and the third valve VV3 are opened to supply the heated vaporized substance and the heated dodecafluoroheptyl acrylate monomer to the vacuum tank VB in the form of steam.

[0151] A microwave irradiation device MI is installed at the end of the rotating section of the main roller MR. The film enters the microwave irradiation device MI along with the fifth tension roller TR5 and the sixth tension roller TR6. Under the conditions of ion acceleration voltage of 300V and substrate temperature of -20°C, the microwave irradiation device MI generates plasma from dodecyl fluoroheptyl acrylate monomer and sputters it onto the film. The dodecyl fluoroheptyl acrylate monomer forms a film with a thickness of 100nm on the hard coating. After film formation, the film is discharged to the body MB along with the seventh tension roller TR7 and the eighth tension roller TR8, and then wound onto the second roller RL2.

[0152] [Example 2]

[0153] Except for the following, all were carried out under the same conditions as in Example 1.

[0154] The ultraviolet absorber comprises a substance in which a methylimine compound and cyanoacrylate are combined in a 1:2 ratio (hereinafter referred to as ultraviolet absorber 2). The combined ultraviolet absorber 2 is combined with polyethylene terephthalate in a 1:1 ratio. The film and hard coating are stacked by the same method as in Example 1.

[0155] pass Figure 11 We observed the manufacturing process of the low-refractive-index layer of the display panel. Figure 11 It is shown Figure 5 The diagram shows the manufacturing process of the low-refractive-index layer of the display panel.

[0156] [Example 3]

[0157] Except for the following, all were carried out under the same conditions as in Example 1.

[0158] The membrane is made of polyethylene terephthalate, with a hard coating applied to the membrane and then dried.

[0159] Next, UV absorber 2 is prepared. UV absorber 2 is added to the boat BT and heat is applied using the heater HT.

[0160] Add the R-type SQ to the different boat BT and apply heat with the heater HT.

[0161] If the membrane rotates and enters above the main roller MR present in the vacuum tank VB, the first valve VV1, the second valve VV2 and the third valve VV3 are opened so that the heated vaporizable substance, the heated ultraviolet absorber 2 and the R-type SQ are supplied to the vacuum tank VB in the form of steam.

[0162] The microwave irradiation device MI generates plasma using ultraviolet absorber 2 and type R SQ, and sputters it onto the film at an 8:2 ratio. A low-refractive-index layer formed by sputtering is deposited on top of the hard coating to achieve a thickness of 100 nm. After film formation, the film is discharged to the body MB via tensioning rollers TR7 and TR8, and then wound onto the second roller RL2.

[0163] [Example 4]

[0164] Except for the following, all were carried out under the same conditions as in Example 3.

[0165] The microwave irradiation device MI generates plasma from ultraviolet absorber 1 and type R SQ, and sputters it onto the film in a 7:3 ratio.

[0166] [Example 5]

[0167] Except for the following, all were carried out under the same conditions as in Example 3.

[0168] Combined with UV absorber 1.

[0169] If the membrane rotates and enters above the main roller MR present in the vacuum tank VB, the first valve VV1, the second valve VV2 and the third valve VV3 are opened so that the heated vaporizable substance, the heated ultraviolet absorber 1 and the R-type SQ are supplied to the vacuum tank VB in the form of steam.

[0170] The microwave irradiation device MI generates plasma from ultraviolet absorber 1 and type R SQ, and sputters it onto the film in an 8:2 ratio.

[0171] [Comparative Example 1]

[0172] Except for the following, all were carried out under the same conditions as in Example 1.

[0173] In the membrane manufacturing process, polyethylene terephthalate is used, and no ultraviolet absorber is added.

[0174] [Comparative Example 2]

[0175] Except for the following, all were carried out under the same conditions as in Comparative Example 1.

[0176] Prepare the reagents for Experiment Example 1 by adding a methylimine compound and benzotriazole to a membrane containing polyethylene terephthalate in a ratio of 1:2.5.

[0177] [Comparative Example 3]

[0178] Except for the following, all were carried out under the same conditions as in Comparative Example 1.

[0179] Comparative Example 3 includes a form that does not contain UV absorber 2 and contains R-type SQ.

[0180] [Experimental Example 1] Transmission Spectroscopy and Reflection Spectroscopy

[0181] Samples of Example 1, Comparative Example 1 and Comparative Example 2 were prepared and placed in a spectrophotometer (CM3700A) to confirm the transmittance and reflectance at 370 nm and 400 nm.

[0182] pass Figure 12 , Figure 13 In accordance with Table 1, observe the transmittance and reflectance of Experimental Example 1, Comparative Example 1, and Comparative Example 2 in the ultraviolet and visible light regions. Figure 12 It is shown Figure 4 The graph shown represents the results of the transmission spectral analysis of the display panel. Figure 13 It is shown Figure 4 The graph shows the results of the reflectance spectral analysis of the display panel. Table 1 shows the data used in the graph.

[0183] Figure 12 The left curve shows the spectral characteristics in the total transmittance portion, while the right curve shows the spectral characteristics in the 80%–100% transmittance segment.

[0184] The transmittance of ultraviolet and visible light at a wavelength of 370 nm was observed. In Comparative Example 1, it was 85.01%, while in Comparative Example 2 and Example 1, the transmittance was 0%. The transmittance of ultraviolet and visible light at a wavelength of 400 nm was observed. In Comparative Example 1, it was 89.88%, while in Comparative Example 2, the transmittance was 82.68%, and in Example 1, the transmittance was 83.18%.

[0185] That is, it can be known that when ultraviolet absorber 1 is added to the film layer FLM, the display device has the effect of blocking ultraviolet rays below the wavelength of 370nm.

[0186] Figure 13 The reflectance spectroscopic spectrum of Example 1 is shown when the ion voltage is 300V. The reflectance of Example 1 is 1.34% at a wavelength of 370nm and 7.6% at a wavelength of 400nm.

[0187] Based on the experimental data, it can be seen that when ultraviolet absorber 1 is added to the FLM film, the window can perform anti-reflection function at wavelengths below 370nm.

[0188] [Table 1]

[0189]

[0190] pass Figure 14 Table 2 shows the optical properties of Example 3 in the ultraviolet and visible light regions. Figure 14 It is shown Figure 5 The graphs showing the ultraviolet and visible light spectroscopic analysis results of the display panel are illustrated in Table 2, which shows the data of the reflectance spectroscopic spectrum.

[0191] First, refer to Figure 14 Observe the transmittance of Example 3. Prepare a window sample of Example 3 and measure the transmittance using a UV-Vis device.

[0192] The transmittance of Example 3 is less than 30% in the ultraviolet absorption region, i.e., 370nm to 410nm, and especially less than 5% in the band below 405nm.

[0193] Therefore, it can be seen that when ultraviolet absorber 2 is added to the low refractive index layer, the display device has the effect of blocking ultraviolet rays at wavelengths below 400nm.

[0194] Next, referring to Table 2, it can be determined that the reflectivity of Example 3 is 1.42% at a wavelength of 550 nm. Therefore, when the ultraviolet absorber 2 is added to the low refractive index layer, the window can play an anti-reflective role below a wavelength of 550 nm.

[0195] [Table 2]

[0196] Wavelength (nm) 360 370 380 390 400 410 420 430 440 450 Reflectivity (%) of Example 3 1.80 1.97 2.23 2.52 2.75 2.86 2.85 2.84 2.76 2.62 Wavelength (nm) 460 470 480 490 500 510 520 530 540 550 Reflectivity (%) of Example 3 2.48 2.33 2.19 2.06 1.91 1.78 1.65 1.55 1.48 1.42

[0197] [Experimental Example 3] Surface property analysis results

[0198] Table 3 shows the characteristics related to the surface hardness of Example 3. Table 3 also shows the initial surface contact angle measurement results. Referring to Table 3, it can be seen that the initial contact angle of Example 3 is greater than 110 degrees. Furthermore, after undergoing eraser abrasion tests at 1 kgf and 5 K, the contact angle measurement was greater than 95 degrees.

[0199] [Table 3]

[0200] Order / degree (°) first The second The third Contact angle of Example 3 112.3 111.9 112.8

[0201] Therefore, it has been confirmed that when ultraviolet absorber 2 is added to the low refractive index layer, it can possess a rigidity capable of preventing defects such as cracks in the window of a flexible display suitable for repeated folding and unfolding. This improves the reliability of the display device.

[0202] [Experimental Example 4] Surface Analysis Results by X-ray Photoelectron Spectroscopy

[0203] pass Figure 15 See Table 4 for an observation of the surface characteristics of Example 3. Figure 15 It is shown Figure 5 The graphs shown are of the surface analysis results of the display panel performed by X-ray photoelectron spectroscopy (XPS). Table 4 shows the surface analysis result data performed by X-ray photoelectron spectroscopy.

[0204] Referring to Table 4 below, the fluorine (F) content inside the membrane of Example 3 is 0.64%, while that of Comparative Example 3 is 17.81%. Furthermore, the oxygen (O) content inside and outside the membrane of Example 3 is 8.64%, while that of Comparative Example 3 is 5.26%.

[0205] Therefore, it can be seen that when ultraviolet absorber 2 is added to the low refractive index layer, the F content inside the film decreases compared to the case where it is not added. Furthermore, it can be seen that the O content increases compared to the comparative example, indicating an increase in Si-O bonds.

[0206] [Table 4]

[0207]

[0208] Reference Figure 15 It can be confirmed that, on the XPS curve, although the surface of Example 3 also shows a CF peak, the peak value of CF2 is particularly high.

[0209] While the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto. Various modifications and improvements made by those skilled in the art using the basic concepts of the present invention as defined in the appended claims also fall within the scope of the present invention.

Claims

1. A display device, comprising: substrate; The display layer is located on the substrate; The base layer is located above the display layer; A hard coating layer is located on the base layer; as well as A low-refractive-index layer is located on top of the hard coating. The base layer contains an ultraviolet absorber.

2. The display device according to claim 1, wherein, The low-refractive-index layer comprises dodecafluoroheptyl acrylate.

3. The display device according to claim 2, wherein, The ultraviolet absorber comprises at least one of methylimine compounds, cyanoacrylates, and benzotriazoles.

4. The display device according to claim 3, wherein, The thickness of the low refractive index layer is 80 nm to 120 nm.

5. The display device according to claim 4, wherein, The base layer comprises polyethylene terephthalate.

6. The display device according to claim 5, wherein, The ultraviolet absorber comprises a mixture of methylimine compounds and benzotriazole in a ratio of 0.8 to 1.2: 2 to 3.

7. The display device according to claim 6, wherein, The base layer comprises a mixture of the polyethylene terephthalate, the methylimine compound, and benzotriazole in a ratio of 0.8–1.2:1.2–0.

8.

8. The display device according to claim 5, wherein, The ultraviolet absorber comprises a mixture of a methylimine compound and a cyanoacrylate in a ratio of 0.8–1.2:1.6–2.

4.

9. The display device according to claim 8, wherein, The base layer comprises a mixture of the polyethylene terephthalate, the methylimine compound, and cyanoacrylate in a ratio of 0.8–1.2:1.2–0.

8.

10. A display device, comprising: substrate; The display layer is located on the substrate; The base layer is located above the display layer; A hard coating layer is located on the base layer; as well as A low-refractive-index layer is located on top of the hard coating. The low-refractive-index layer contains an ultraviolet absorber.

11. The display device according to claim 10, wherein, The thickness of the low refractive index layer is 80 nm to 120 nm.

12. The display device according to claim 10, wherein, The thickness of the substrate layer is 40 μm to 90 μm. The thickness of the hard coating is 3μm to 7μm.

13. The display device according to claim 12, wherein, The low-refractive-index layer comprises a random silsesquioxane monomer with 12 perfluoroalkyl groups and 6 reactive groups.

14. The display device according to claim 13, wherein, Each of the 12 perfluoroalkyl groups is C3F7, C4F9, and C5F7. 11 Any one of them.

15. The display device according to claim 13, wherein, The ultraviolet absorber comprises at least one of methylimine compounds, cyanoacrylates, and benzotriazoles.

16. The display device according to claim 15, wherein, The base layer comprises polyethylene terephthalate.

17. The display device according to claim 15, wherein, The ultraviolet absorber comprises a mixture of a methylimine compound and a cyanoacrylate in a ratio of 0.8–1.2:1.6–2.

4.

18. The display device according to claim 17, wherein, The low refractive index layer comprises a mixture of the silsesquioxane monomer and the ultraviolet absorber in a ratio of 5.4–9.6:1.6–2.

4.

19. The display device according to claim 15, wherein, The ultraviolet absorber comprises a mixture of methylimine compounds and benzotriazole in a ratio of 0.8 to 1.2: 2 to 3.

20. The display device according to claim 19, wherein, The low refractive index layer comprises a mixture of the silsesquioxane monomer and the ultraviolet absorber in a ratio of 5.4–9.6:1.6–2.4.

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