Display device

Abstract

The display device includes: a display panel including a front surface; and a front laminated structure disposed on the one surface of the display panel, the front laminated structure including: a cover window; and a first composite member disposed on the cover window, the first composite member including: a base layer; and a resin layer disposed on the base layer, the coefficient of thermal expansion of the first composite member being 20 ppm / DEG C to 45 ppm / DEG C in a temperature range of-40 DEG C to 60 DEG C.

Description

Technical Field

[0001] The utility model relates to a display device. Background Art

[0002] Electronic devices such as smartphones, tablet PCs, digital cameras, notebook computers, navigation devices, and digital televisions that provide images to users include display devices for displaying images. In recent years, foldable display devices have attracted much attention. Foldable display devices are excellent in portability and can have a wide screen, thus having all the advantages of smartphones and tablet PCs.

[0003] The foldable display device stacks and combines multiple stacked structures, and uses a combination component between each stacked structure. The combination component can not only play the role of combining the stacked structures, but also play the role of protecting the stacked structures of the display device from external impact. Therefore, the combination component is required to have impact resistance properties that can protect the stacked structures of the display device from external impact. Utility Model Content

[0004] The problem to be solved by the present invention is to provide a display device capable of improving impact resistance characteristics.

[0005] The subject of the present invention is not limited to the subject mentioned above, and those skilled in the art should be able to clearly understand other technical subjects not mentioned through the following description.

[0006] A display device for solving the above-mentioned problem may include: a display panel including a front surface; and a front laminated structure arranged on the front surface of the display panel, the front laminated structure including: a cover window; and a first composite component arranged on the cover window, the first composite component including: a base layer; and a resin layer arranged on the base layer, the thermal expansion coefficient of the first composite component being 20ppm / ℃ to 45ppm / ℃ in a temperature range of -40℃ to 60℃.

[0007] The base layer may have a thickness of 65 μm to 75 μm.

[0008] The resin layer may have a thickness of 20 μm to 35 μm.

[0009] The first composite member may have a storage modulus of 2.7 GPa to 2.9 GPa at 25°C.

[0010] The first composite member may have a loss modulus of elasticity of 0.07 GPa to 0.09 GPa at 25°C.

[0011] It may be that the loss coefficient of the first composite member is 0.024 to 0.033 at 25°C.

[0012] In addition, the display device may include: a display panel, including a surface located in the front; and a front laminated structure, arranged on the surface of the display panel, the front laminated structure including: a cover window; a first composite component, arranged on the cover window; and a second composite component, arranged between the cover window and the display panel, the first composite component and the second composite component respectively include: a base layer; a resin layer, arranged on the base layer, and the energy storage modulus of each of the first composite component and the second composite component is 2.7GPa to 2.9GPa at 25°C.

[0013] It may be that the thermal expansion coefficient of each of the first composite member and the second composite member is 20 ppm / °C to 45 ppm / °C in a temperature range of -40°C to 60°C.

[0014] The first composite member and the second composite member may each have a loss modulus of elasticity of 0.07 GPa to 0.09 GPa at 25°C.

[0015] The first composite member and the second composite member may each have a loss coefficient of 0.024 to 0.033 at 25°C.

[0016] Details of other embodiments are included in the detailed description and accompanying drawings.

[0017] (Effect of utility model)

[0018] The display device includes a composite component having physical properties of a thermal expansion coefficient, storage elastic modulus, loss elastic modulus and loss coefficient suitable for a foldable display device, thereby improving the impact resistance of the display device and eliminating pressure when folding.

[0019] The effects of the embodiments are not limited to the above-exemplified ones, and more effects are included in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a perspective view showing a state where a display device according to an embodiment is unfolded.

[0021] Figure 2 It is a perspective view showing a state where the display device according to an embodiment is folded.

[0022] Figure 3 is a cross-sectional view of a display device according to an embodiment in an unfolded state.

[0023] Figure 4 is a cross-sectional view of a display device according to an embodiment in a folded state.

[0024] Figure 5 is a cross-sectional view of a display panel according to an embodiment.

[0025] Figure 6 It is a cross-sectional view showing a first composite member according to an embodiment.

[0026] Figure 7 is a cross-sectional view of a display device according to another embodiment.

[0027] Figure 8 is a cross-sectional view of a display device according to still another embodiment.

[0028] Figures 9 to 11 The present invention is a cross-sectional view showing a method for manufacturing a display device according to an embodiment of the present invention in steps.

[0029] Fig.12 : is a graph showing the pen drop test results of the display device samples according to Experimental Example 1.

[0030] Explanation of symbols:

[0031] 10: display device; 100: display panel; 200: front laminated structure; 300: rear laminated structure; 220: cover window; 230: impact absorbing layer; 400: composite component; 410: base layer; 420: resin layer. DETAILED DESCRIPTION

[0032] References and Attachments Figure 1 The advantages, features and methods of achieving the advantages and features of the present invention will become clear from the detailed embodiments described below. However, the present invention is not limited to the embodiments disclosed below and can be implemented in different forms. The embodiments are only provided to make the disclosure of the present invention complete and to fully inform the technical personnel of the field of the present invention of the scope of the present invention. The present invention should be defined only by the scope of the claims.

[0033] The case where an element or layer is located on other elements or layers includes not only the case where it is directly located on other elements, but also the case where other layers or other elements exist between them. Similarly, components referred to as "below", "left" and "right" include both the case where they are directly adjacent to other elements and the case where other layers or other elements exist between them. Throughout the specification, the same symbol refers to the same constituent element.

[0034] Although the terms "first" and "second" are used to describe each component, each component is of course not limited to these terms. These terms are only used to distinguish one component from other components. Therefore, within the technical concept of the present invention, the first component mentioned below can of course also be the second component.

[0035] Hereinafter, embodiments will be described with reference to the accompanying drawings.

[0036] Figure 1 It is a perspective view showing a state where a display device according to an embodiment is unfolded. Figure 2 It is a perspective view showing a state where the display device according to an embodiment is folded.

[0037] Reference Figure 1 The display device 10 involved in one embodiment may be a foldable display device. The display device 10 is described with the application to smart phones as the center, but is not limited to this. For example, in addition to smart phones, the display device 10 involved in the embodiments of this specification may also be applied to various household appliances or Internet of Things devices such as mobile phones, tablet PCs, PDAs (Personal Digital Assistants), PMPs (Portable Multimedia Players), televisions, game consoles, watch-type electronic devices, head-mounted displays, personal computer monitors, notebook computers, car navigation systems, car dashboards, digital cameras, video cameras, external advertising boards, electro-optical boards, medical devices, inspection devices, refrigerators, washing machines, etc. . Specific embodiments are described below with reference to the accompanying drawings.

[0038] exist Figure 1 and Figure 2 In the diagram, the first direction DR1 is a direction parallel to one side of the display device 10 when viewed on a plane, and may be, for example, the horizontal direction of the display device 10. The second direction DR2 is a direction parallel to another side of the display device 10 when viewed on a plane, and may be the vertical direction of the display device 10. The third direction DR3 may be the thickness direction of the display device 10.

[0039] In one embodiment, the display device 10 may be formed in a rectangular shape when viewed on a plane. When viewed on a plane, the display device 10 may be in a rectangular shape with vertical corners or a rectangular shape with rounded corners. When viewed on a plane, the display device 10 may include two short sides arranged in a first direction DR1 and two long sides arranged in a second direction DR2.

[0040] The display device 10 includes a display area DA and a non-display area NDA. When viewed on a plane, the shape of the display area DA may correspond to the shape of the display device 10. For example, when viewed on a plane, when the display device 10 is rectangular, the display area DA may also be rectangular.

[0041] The display area DA may be an area including a plurality of pixels and displaying an image. The plurality of pixels may be arranged in row and column directions. When viewed on a plane, the plurality of pixels may be a rectangle, a rhombus, or a square, but are not limited thereto. For example, when viewed on a plane, the plurality of pixels may be a quadrilateral other than a rectangle, a rhombus, or a square, a polygon other than a quadrilateral, a circle, or an ellipse.

[0042] The non-display area NDA may be an area that does not include pixels and does not display an image. The non-display area NDA may be disposed around the display area DA. The non-display area NDA may be configured as follows: Figure 1 and Figure 2 As shown, the display area DA is configured to surround the display area DA, but is not limited thereto. The display area DA may be partially surrounded by the non-display area NDA.

[0043] In one embodiment, the display device 10 can maintain both a folded state and an unfolded state. Figure 2 As shown, the display device 10 can be folded in an in-folding manner with the display area DA arranged on the inside. When the display device 10 is folded in an in-folding manner, the upper surfaces of the display device 10 can be arranged to face each other. As another example, the display device 10 can be folded in an out-folding manner with the display area DA arranged on the outside. When the display device 10 is folded in an out-folding manner, the lower surfaces of the display device 10 can be arranged to face each other.

[0044] In one embodiment, the display device 10 may be a foldable device. In this specification, a foldable device refers to a device that can be folded, including not only a folded device, but also a device that can have both a folded state and an unfolded state. In addition, folding is representative of a situation where it is folded at an angle of about 180°, but is not limited thereto. When the folding angle exceeds 180° or is less than 180°, for example, when it is bent at an angle of more than 90° and less than 180° or at an angle of more than 120° and less than 180°, it can also be understood as being folded. At the same time, the folded state may refer to a folded state in a state where it is bent beyond the unfolded state even if a fully folded state is not formed. For example, even if it is bent at an angle of less than 90°, in order to distinguish it from an abnormal unfolded state where the maximum folding angle is more than 90°, it can also be expressed as being in a folded state. When folded, the radius of curvature may be less than 5 mm, and the radius of curvature may preferably be in the range of 1 mm to 2 mm or about 1.5 mm, but is not limited thereto.

[0045] In one embodiment, the display device 10 may include a folding area FDA, a first non-folding area NFA1, and a second non-folding area NFA2. The folding area FDA may be an area where the display device 10 is folded, and the first non-folding area NFA1 and the second non-folding area NFA2 may be areas where the display device 10 is not folded.

[0046] The first non-folding area NFA1 may be arranged on one side of the folding area FDA, for example, on the upper side of the folding area FDA. The second non-folding area NFA2 may be arranged on the other side of the folding area FDA, for example, on the lower side of the folding area FDA. The folding area FDA may be an area curved with a predetermined curvature.

[0047] In one embodiment, the folding area FDA of the display device 10 may also be located at a specific position. In the display device 10, there may be one or more than two folding areas FDA located at a specific position. In other embodiments, the folding area FDA may also be located in an unspecified position in the display device 10 but may be freely set in various areas.

[0048] In one embodiment, the display device 10 can be folded in the second direction DR2 , so that the length of the display device 10 in the second direction DR2 can be reduced to about half, so that the user can carry the display device 10 more conveniently.

[0049] In one embodiment, the direction of folding the display device 10 is not limited to the second direction DR2. For example, the display device 10 may be folded in the first direction DR1. In this case, the length of the display device 10 in the first direction DR1 may be reduced to approximately half.

[0050] exist Figure 1 and Figure 2 In the embodiment, the display area DA and the non-display area NDA are respectively overlapped with the folding area FDA, the first non-folding area NFA1 and the second non-folding area NFA2, but the present invention is not limited thereto. For example, the display area DA and the non-display area NDA may respectively overlap with at least one of the folding area FDA, the first non-folding area NFA1 and the second non-folding area NFA2.

[0051] Figure 3 is a cross-sectional view of a display device according to an embodiment in an unfolded state. Figure 4 is a cross-sectional view of a display device according to an embodiment in a folded state.

[0052] Reference Figure 3 and Figure 4 The display device 10 may include a display panel 100, a front stacked structure 200 stacked in front of the display panel 100, and a rear stacked structure 300 stacked in the rear of the display panel 100. The front stacked structure 200 may include at least one of the bonding components 251 to 252, and the rear stacked structure 300 may include at least one of the bonding components 351 to 353. Here, the front of the display panel 100 indicates the direction in which the display panel 100 displays a screen, and the rear of the display panel 100 indicates the opposite direction of the front. One side of the display panel 100 is located in the front, and the other side of the display panel 100 is located in the rear.

[0053] The display panel 100 is a panel for displaying a picture or an image, and as an example, it may include not only self-luminous display panels such as an organic light-emitting display panel (OLED), an inorganic light-emitting display panel (inorganic EL), a quantum dot light-emitting display panel (QED), a micro-LED display panel (micro-LED), a nano-LED display panel (nano-LED), a plasma display panel (PDP), a field emission display panel (FED), and a cathode ray display panel (CRT), but also light-receiving display panels such as a liquid crystal display panel (LCD) and an electrophoretic display panel (EPD). In the following, the display panel 100 is described by taking an organic light-emitting display panel as an example, but as long as no special distinction is required, the organic light-emitting display panel applicable to the embodiment will be simply referred to as the display panel 100. However, the embodiment is not limited to the organic light-emitting display panel, and within the scope of the shared technical concept, it may also be applicable to the display panel 100 listed above or known in the art.

[0054] The display panel 100 may further include a touch component. The touch component may be provided as a panel or film independent of the display panel 100 and attached to the display panel 100, but the touch component may also be provided in the form of a touch layer inside the display panel 100. In the following embodiments, the touch component is provided inside the display panel 100 and included in the display panel 100, but is not limited thereto.

[0055] Figure 5 is a cross-sectional view of a display panel according to an embodiment.

[0056] Reference Figure 5 The display device 10 according to an embodiment may include a display panel 100. The display panel 100 may include a base substrate 11, a first electrode 12, a pixel definition film 13, a light emitting layer 14, a second electrode 15, and an encapsulation layer 20. The display panel 100 may further include a touch sensor 40.

[0057] The base substrate 11 may be an insulating substrate. The base substrate 11 may be soft and may include a flexible polymer. Here, the polymer may be polyimide (PI), polyethersulphone (PES), polyacrylate (PA), polyarylate (PAR), polyetherimide (PEI), polyethylene napthalate (PEN), polyethylene terepthalate (PET), polyphenylene sulfide (PPS), polyallylate, polycarbonate (PC), cellulose triacetate (CAT), cellulose acetate propionate (CAP), or a combination thereof.

[0058] A first electrode 12 may be disposed on the base substrate 11. In one embodiment, the first electrode 12 may be an anode. Although not shown, a plurality of structures may be disposed between the base substrate 11 and the first electrode 12. As one embodiment, the plurality of structures may include a buffer layer, a plurality of conductive wirings, an insulating layer, and a plurality of thin film transistors.

[0059] A pixel definition film 13 may be disposed on the first electrode 12. The pixel definition film 13 may include an opening that exposes at least a portion of the first electrode 12.

[0060] A light-emitting layer 14 may be disposed on the first electrode 12. In one embodiment, the light-emitting layer 14 may emit one of red light, green light, and blue light. The wavelength of the red light may be approximately 620 nm to 750 nm, and the wavelength of the green light may be approximately 495 nm to 570 nm. In addition, the wavelength of the blue light may be approximately 450 nm to 495 nm. The light-emitting layer 14 may be formed of a single layer. Alternatively, the light-emitting layer 14 may also be formed of a structure in which a plurality of organic light-emitting layers are stacked (e.g., a tandem structure). As another embodiment, the light-emitting layer 14 may emit white light. In the case where the light-emitting layer 14 emits white light, the light-emitting layer 14 may have a form in which a red organic light-emitting layer, a green organic light-emitting layer, and a blue organic light-emitting layer are stacked.

[0061] The second electrode 15 may be disposed on the light emitting layer 14 and the pixel definition film 13. As an embodiment, the second electrode 15 may be formed on the entire surface of the light emitting layer 14 and the pixel definition film 13. In some embodiments, the second electrode 15 may be a cathode.

[0062] The first electrode 12 , the second electrode 15 , and the light-emitting layer 14 can constitute a light-emitting element EL.

[0063] An encapsulation layer 20 may be provided on the light emitting element EL. The encapsulation layer 20 may seal the light emitting element EL to prevent moisture or the like from flowing into the light emitting element EL from the outside.

[0064] In one embodiment, the encapsulation layer 20 may be implemented by thin film encapsulation (Thin Film Encapsulation), and may include one or more organic films and one or more inorganic films. For example, the encapsulation layer 20 may include a first inorganic film 21 located on the second electrode 15, an organic film 22 located on the first inorganic film 21, and a second inorganic film 23 located on the organic film 22.

[0065] The first inorganic film 21 can prevent moisture, oxygen, etc. from penetrating into the light emitting element EL. The first inorganic film 21 can be formed of silicon nitride, aluminum nitride, zirconium nitride, titanium nitride, hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide, titanium oxide, tin oxide, cerium oxide, silicon oxynitride, etc.

[0066] An organic film 22 may be provided on the first inorganic film 21. The organic film 22 may improve flatness. The organic film 22 may be formed of a liquid organic material, such as an acrylic resin, a methacrylic resin, a polyisoprene resin, a vinyl resin, an epoxy resin, a urethane resin, a cellulose resin, and a perylene resin. Such an organic material may be provided on the base substrate 11 by deposition, printing, and coating, and may be subjected to a curing process.

[0067] A second inorganic film 23 may be provided on the organic film 22. The second inorganic film 23 may perform substantially the same or similar function as the first inorganic film 21, and may be formed of a material substantially the same or similar to the first inorganic film 21. The second inorganic film 23 may completely cover the organic film 22. In some embodiments, the second inorganic film 23 and the first inorganic film 21 may be connected to each other in the non-display area NDA to form an inorganic-inorganic bond. However, the structure of the encapsulation layer 20 is not limited thereto, and the stacked structure of the encapsulation layer 20 may be changed in various ways. Alternatively, in other embodiments, the encapsulation layer 20 may also be formed of a glass substrate or the like.

[0068] The touch sensor 40 may be disposed on the encapsulation layer 20. In one embodiment, the touch sensor 40 may be directly located on the encapsulation layer 20. That is, the encapsulation layer 20 may function as a base of the touch sensor 40.

[0069] The touch sensor 40 may include a touch element layer 41 and a protective layer 43. The touch element layer 41 may include touch electrodes and touch signal lines connected to the touch electrodes. In one embodiment, the touch electrodes may include metal and may have a mesh shape. That is, the touch electrodes may be formed of a metal mesh pattern, thereby improving the flexibility of the touch element layer 41.

[0070] The protective layer 43 may be located on the touch element layer 41 to protect the touch element layer 41. In one embodiment, the protective layer 43 may include organic matter, for example, may be formed of an acrylic polymer. When the protective layer 43 is formed of an organic matter, the flexibility of the touch sensor 40 may be improved.

[0071] Refer again Figure 3 and Figure 4 A front stacked structure 200 may be disposed in front of the display panel 100. The front stacked structure 200 may include an impact absorbing layer 230, a cover window 220, and a first composite member 400 which are sequentially stacked from the display panel 100 toward the front.

[0072] The impact absorbing layer 230 can protect the structure of the lower display panel 100 from external impact. In one embodiment, the impact absorbing layer 230 can be a polymer film. The polymer film can include at least one of PET (PolyEthylene Terephthalate), PEN (PolyEthyleneNaphthalate), PES (Polyether Sulfone), PI (PolyImide), PAR (PolyARylate), PC (PolyCarbonate), PMMA (PolyMethylMethAcrylate) or COC (CycloOlefin Copolymer) resin.

[0073] In some embodiments, a polarizing component may be included instead of the impact absorbing layer 230. The polarizing component may polarize the light passing therethrough. The polarizing component may play a role in reducing the reflection of external light. In one embodiment, the polarizing component may be a polarizing film. The polarizing film may protect the polarizing layer and a protective substrate that clamps the polarizing layer from the upper and lower parts. The polarizing layer may include a polyvinyl alcohol film. The polarizing layer may extend in one direction. The extending direction of the polarizing layer may be the absorption axis, and the direction perpendicular to the absorption axis may be the transmission axis of the polarizing layer. The protective substrate may be respectively arranged on one side and the other side of the polarizing layer. The protective substrate may be formed of a cellulose resin such as cellulose triacetate, a polyester resin, etc., but is not limited thereto.

[0074] A cover window 220 may be disposed in front of the impact absorbing layer 230. The cover window 220 plays a role in protecting the display panel 100. The cover window 220 may be formed of a transparent material. For example, the cover window 220 may be formed to include glass or plastic.

[0075] In the case where the cover window 220 includes glass, the glass may be ultra-thin (UTG) glass or film glass. Ultra-thin glass (UTG) may be strengthened to have a predetermined stress distribution inside. Strengthened ultra-thin glass (UTG) is better able to prevent cracks, crack propagation, breakage, etc. caused by external impact than before strengthening. Ultra-thin glass (UTG) strengthened by the strengthening process may have various stresses according to regions.

[0076] In the case where the glass is formed of ultra-wave glass or thin film glass, it can have flexible properties, so that it can have bendable, curved, foldable or curlable properties. The thickness of the glass can be, for example, in the range of 10 μm to 300 μm, specifically, a glass with a thickness of 10 μm to 100 μm or a thickness of about 50 μm can be used. The glass of the cover window 220 may include soda-lime glass, alkaline aluminosilicate glass, borosilicate glass or lithium aluminosilicate glass. The glass of the cover window 220 may include chemically strengthened or thermally strengthened glass in order to have high strength. Chemical strengthening can be achieved by an ion exchange treatment process in an alkaline salt. The ion exchange treatment process can also be performed more than twice. In addition, the cover window 220 can also be formed by coating glass with a thin film on both sides of the polymer film.

[0077] Refer again Figure 3 and Figure 4 In the case where the cover window 220 includes plastic, it is more advantageous to exhibit flexible characteristics such as folding. Examples of plastics applicable to the cover window 220 include polyimide, polyacrylate, polymethylmethacrylate (PMMA), polycarbonate (PC), polyethylenenaphthalate (PEN), polyvinylidene chloride, polyvinylidene difluoride (PVDF), polystyrene, ethylene vinylalcohol copolymer, polyethersulphone (PES), polyetherimide (PEI), polyphenylenesulfide (PPS), polyarylate, triacetyl cellulose (TAC), cellulose acetate propionate (CAP), etc., but are not limited thereto. The plastic cover window 220 may be formed to include one or more of the plastic substances listed above.

[0078] The first composite member 400 may be disposed in front of the cover window 220. The first composite member 400 may perform at least one of anti-scattering, impact absorption, anti-scratch, anti-fingerprint, and anti-glare functions of the cover window 220. The first composite member 400 will be described in detail later.

[0079] The front stacked structure 200 may include front combining parts 251-252 for combining adjacent stacked parts. For example, a first combining part 251 may be disposed between the cover window 220 and the impact absorbing layer 230 to combine them, and a second combining part 252 may be disposed between the impact absorbing layer 230 and the display panel 100 to combine them. That is, the front combining parts 251-252 are parts for attaching each layer to one side of the display panel 100, the first combining part 251 may be a window combining part for attaching the cover window 220, and the second combining part 252 may be a impact absorbing layer combining part for attaching the impact absorbing layer 230. Both of the front combining parts 251-252 may be optically transparent.

[0080] The rear stacked structure 300 is disposed behind the display panel 100. The rear stacked structure 300 may include a polymer film layer 310, a cushion layer 320, and a plate 330 which are sequentially stacked from the display panel 100 toward the rear.

[0081] The polymer film layer 310 may include a polymer film. The polymer film layer 310 may include, for example, polyimide (PI), polyethylene terephthalate (PET), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polysulfone (PSF), polymethyl methacrylate (PMMA), cellulose triacetate (TAC), cycloolefin polymer (COP), etc. The polymer film layer 310 may include a functional layer on at least one side. The functional layer may include, for example, a light absorbing layer. The light absorbing layer may include a light absorbing substance such as a black pigment or a black dye. The light absorbing layer may be formed on the polymer film by coating or printing using black ink.

[0082] A cushion layer 320 may be disposed behind the polymer film layer 310. The cushion layer 320 may absorb external impact to prevent the display panel 100 from being damaged. The cushion layer 320 may be formed of a single-layer or multi-layer laminated film. The cushion layer 320 may be formed, for example, to include an elastic material such as polyurethane resin or polyethylene resin. In one embodiment, the cushion layer 320 may be formed of a foam material similar to a sponge.

[0083] A plate 330 may be disposed behind the pad 320. The plate 330 may be a support member for coupling the display device 10 to the frame. The plate 330 may be formed to include a material having rigidity. In one embodiment, the plate 330 may be formed of a metal alloy such as stainless steel (SUS) or a single metal.

[0084] like Figure 3 and Figure 4As shown, the plate 330 may be separated based on the folding area FDA in order to smoothly fold the display device 10, but is not limited thereto. For example, a first plate as a part of the plate 330 may be arranged in the first non-folding area NFA1, and a second plate as another part of the plate 330 may be arranged in the second non-folding area NFA2. The first plate and the second plate may be physically spaced apart from each other with the folding area FDA as the center.

[0085] The rear stacked structure 300 may include rear combining components 351 to 353 that combine adjacent stacked components. For example, a third combining component 351 may be configured between the display panel 100 and the polymer film layer 310 to combine them, a fourth combining component 352 may be configured between the polymer film layer 310 and the cushion layer 320 to combine them, and a fifth combining component 353 may be configured between the cushion layer 320 and the board 330 to combine them. That is, the rear combining components 351 to 353 are components that attach each layer to the other side of the display panel 100, the third combining component 351 may be a polymer film combining component that attaches the polymer film layer 310, the fourth combining component 352 may be a cushion layer combining component that attaches the cushion layer 320, and the fifth combining component 353 may be a board combining component that attaches the board 330. In the case where the board 330 is separated with the folding area FDA as the center, the fifth combining component 353 may also be separated in the same shape, but as Figure 3 As shown, the fifth connecting member 353 may be connected into one instead of being separated according to the non-folding areas NFA1 and NFA2.

[0086] In the case where the display device 10 performs display only toward the front surface, the rear coupling members 351 to 353 may be different from the front coupling members 251 to 252 and do not necessarily need to be optically transparent.

[0087] The front coupling parts 251-252 and the rear coupling parts 351-353 may include adhesive materials, respectively. The front coupling parts 251-252 and the rear coupling parts 351-353 may include optically transparent resin (OCR: Optical Clear Resin). The front coupling parts 251-252 and the rear coupling parts 351-353 may have the same composition, but may have different compositions depending on their respective positions and objects to be coupled.

[0088] The first bonding component 251, the second bonding component 252, the third bonding component 351, the fourth bonding component 352, and the fifth bonding component 353 may each have a thickness of 300 μm or less. In one embodiment, the thickness of each bonding component 251-252, 351-353 may be less than 200 μm, and at least a portion of each bonding component 251-252, 351-353 may have a thickness of 100 μm or less. There is no lower limit on the thickness of each bonding component 251-252, 351-353, but in order to allow them to exert the minimum adhesive force, the lower limit may be more than 10 μm. In one embodiment, the first bonding component 251, the second bonding component 252, the third bonding component 351, the fourth bonding component 352, and the fifth bonding component 353 may each have a thickness of 25 μm to 100 μm. Since the first connecting member 251 , the second connecting member 252 , the third connecting member 351 , the fourth connecting member 352 , and the fifth connecting member 353 each have a thickness of 25 μm to 100 μm, peeling between components included in the display device 10 can be prevented when the display device 10 is folded.

[0089] Each of the coupling members 251 to 252 and 351 to 353 may be formed of a single adhesive layer or a plurality of laminated adhesive layers, or may include adhesive layers on one side and the other side of a base material such as a double-sided tape.

[0090] The aforementioned display device 10 is a foldable display device, and the first composite component 400 can play a role in alleviating the bending and pressure of the display device 10. In order to minimize the pressure when the display device 10 is folded, it is advantageous for each of the combining components 251-252, 351-353 to have a low storage modulus. In addition, the display device 10 needs to have an impact-resistant property that can withstand the impact when an impact is applied from the outside. In particular, the first composite component 400 exposed to the outside of the display device 10 must have an impact-resistant property.

[0091] In one embodiment, the first composite member 400 may have thermal expansion coefficient, energy storage modulus, and impact resistance characteristics so as to be easily used in a foldable display device.

[0092] Figure 6 It is a cross-sectional view showing a first composite member according to an embodiment.

[0093] Reference Figure 3 and Figure 6 In one embodiment, a first composite component 400 may include a base layer 410 and a resin layer 420 disposed on one side of the base layer 410 .

[0094] The base layer 410 can support the first composite component 400 and perform at least one of the functions of anti-scattering, impact absorption, anti-scratch, anti-fingerprint and anti-glare of the cover window 220. The base layer 410 can be formed to include a transparent polymer film. For example, the transparent polymer film may include at least one of PET (PolyEthylene Terephthalate), PEN (PolyEthylene Naphthalate), PES (Polyether Sulfone), PI (PolyImide), PAR (PolyARylate), PC (PolyCarbonate), PMMA (PolyMethyl MethAcrylate) or COC (CycloOlefin Copolymer) resins. In an exemplary embodiment, the base layer 410 can be formed of PET having a predetermined rigidity and small deformation.

[0095] The base layer 410 may be formed with a predetermined thickness in consideration of impact resistance, bendability and pressure when folded. The thickness T1 of the base layer 410 may be less than 100 μm. In one embodiment, the thickness T1 of the base layer 410 may be less than 80 μm. Preferably, the thickness T1 of the base layer 410 may be 65 μm to 75 μm.

[0096] The resin layer 420 may be a layer for bonding the base layer 410 to the cover window 220. The resin layer 420 may include a transparent resin having adhesive properties. In an embodiment, the resin layer 420 may include at least one of a silicone resin, an acrylate resin, and a urethane resin. For example, the silicone resin may include a siloxane resin. In an exemplary embodiment, the resin layer 420 may be formed of a siloxane resin.

[0097] The resin layer 420 may be formed with a predetermined thickness in consideration of impact resistance, bending resistance and pressure when folded. Considering the increase in the thermal expansion coefficient of the first composite part 400, the thickness T2 of the resin layer 420 may be less than 35 μm. Preferably, the thickness T2 of the resin layer 420 may be 20 μm to 35 μm.

[0098] The first composite component 400 may have a thermal expansion coefficient within a predetermined range. The thermal expansion coefficient may serve as a factor that determines whether cracks are generated when folding. If the thermal expansion coefficient is high, cracks may be generated in the first composite component 400 when folded at low temperature, and the folding reliability may be reduced. According to one embodiment, the thermal expansion coefficient of the first composite component 400 may be 20ppm / °C to 45ppm / °C. The thermal expansion coefficient of the first composite component 400 is measured using the method of the experimental example described later, for example, in a temperature range of -40°C to 60°C. If the thermal expansion coefficient of the first composite component 400 is above 20ppm / °C, the foldability of the first composite component 400 can be improved, and if the thermal expansion coefficient of the first composite component 400 is below 45ppm / °C, cracks can be prevented from being generated when folded at low temperature.

[0099] The first composite component 400 may have the properties of storage elastic modulus, loss elastic modulus and loss coefficient. The component attached to the foldable display device can eliminate the pressure during folding only if the storage elastic modulus is high and the loss elastic modulus is low and the loss coefficient based on this is low. In one embodiment, the storage elastic modulus of the first composite component 400 may be 2GPa to 3.5GPa. In addition, the component attached to the foldable display device can eliminate the pressure caused by temperature change only if the elastic modulus has low temperature dependence. In one embodiment, the storage elastic modulus of the first composite component 400 can be formed in the range of 3.0GPa to 3.5GPa under a temperature condition of -20°C. In addition, the storage elastic modulus of the first composite component 400 can be formed in the range of 2.5GPa to 3.0GPa under a temperature condition of 60°C, and in the range of 2GPa to 2.5GPa under a temperature condition of 80°C. Under a temperature condition of 25°C similar to the temperature condition of the actual use of the display device 10, the storage elastic modulus of the first composite component 400 can be formed in the range of 2.7GPa to 2.9GPa.

[0100] The loss modulus of elasticity of the first composite member 400 may be 0.04 GPa to 0.12 GPa. Specifically, the loss modulus of elasticity of the first composite member 400 may be formed in the range of 0.10 GPa to 0.12 GPa under a temperature condition of -20°C, in the range of 0.04 GPa to 0.06 GPa under a temperature condition of 60°C, and in the range of 0.06 GPa to 0.08 GPa under a temperature condition of 80°C. Under a temperature condition of 25°C similar to the temperature condition under which the display device 10 is actually used, the loss modulus of elasticity of the first composite member 400 may be formed in the range of 0.07 GPa to 0.09 GPa.

[0101] The ratio of the loss modulus to the storage modulus (i.e., the loss coefficient) of the first composite component 400 may be 0.011 to 0.060. Specifically, the loss coefficient of the first composite component 400 may be 0.028 to 0.040 at a temperature of -20°C, 0.013 to 0.024 at a temperature of 60°C, and 0.024 to 0.04 at a temperature of 80°C. Under a temperature of 25°C similar to the temperature condition under which the display device 10 is actually used, the loss coefficient of the first composite component 400 may be 0.024 to 0.033.

[0102] As described above, the first composite component 400 involved in the embodiment can exhibit a storage elastic modulus of 2.7 GPa to 2.9 GPa, a loss elastic modulus of 0.07 GPa to 0.09 GPa, and a loss coefficient of 0.024 to 0.033 under a temperature condition of 25°C similar to the temperature condition of actual use, thereby reducing the pressure when the display device 10 is folded, thereby preventing the occurrence of cracks and improving the impact resistance.

[0103] Hereinafter, a display device 10 according to other embodiments will be described. Figure 7 and Figure 8 The case where the first composite member 400 is applied to another position is described as an example.

[0104] Figure 7 is a cross-sectional view of a display device according to another embodiment. Figure 8 is a cross-sectional view of a display device according to still another embodiment.

[0105] Reference Figure 7 The display device 10 of this embodiment may be provided with a front stacked structure 200 in front of the display panel 100. The front stacked structure 200 may include a first composite component 400, a cover window 220, and a cover window protective layer 210 sequentially stacked from the display panel 100 toward the front.

[0106] The cover window protection layer 210 may perform at least one of anti-scattering, impact absorption, anti-scratch, anti-fingerprint and anti-glare functions of the cover window 220. The cover window protection layer 210 may be formed to include a transparent polymer film. The transparent polymer film may include at least one of PET (PolyEthylene Terephthalate), PEN (PolyEthylene Naphthalate), PES (Polyether Sulfone), PI (PolyImide), PAR (PolyARylate), PC (PolyCarbonate), PMMA (PolyMethyl MethAcrylate) or COC (CycloOlefin Copolymer) resins.

[0107] A first combining member 251 may be disposed between the cover window protection layer 210 and the cover window 220 to combine them, and a second combining member 252 may be disposed between the cover window 220 and the first composite member 400 to combine them.

[0108] In this embodiment, the above-mentioned Figure 3 The impact absorbing layer ( Figure 3 The first composite component 400 may include a base layer 410 and a resin layer 420 disposed on one side of the base layer 410. The base layer 410 may be formed to include a transparent polymer film, thereby replacing Figure 3 The impact absorbing layer 230 may be provided between the first composite member 400 and the display panel 100 to combine them.

[0109] In addition, refer to Figure 8 The display device 10 according to another embodiment may include a first composite component 400 and a second composite component 500. Specifically, the front stacked structure 200 may include the second composite component 500, the cover window 220, and the first composite component 400 stacked in sequence from the display panel 100 toward the front.

[0110] The first composite component 400 may be used in the above-mentioned Figure 3 The first composite component described in ( Figure 3 The second composite component 500 may be the same as in the above-mentioned Figure 7 The first composite component described in ( Figure 7 The same as "400" in the example above.

[0111] The first composite component 400 may include a first substrate layer 410 and a first resin layer 420, and the second composite component 500 may include a second substrate layer 510 and a second resin layer 520. The first resin layer 420 of the first composite component 400 may be disposed between the first substrate layer 410 and the cover window 220, and the second resin layer 520 of the second composite component 500 may be disposed between the second substrate layer 510 and the display panel 100.

[0112] The storage modulus of each of the first composite component 400 and the second composite component 500 may be 2.7 GPa to 2.9 GPa at 25° C., and the thermal expansion coefficient may be 20 ppm / ° C. to 45 ppm / ° C. in a temperature range of −40° C. to 60° C. In addition, the loss modulus of each of the first composite component 400 and the second composite component 500 may be 0.07 GPa to 0.09 GPa at 25° C., and the loss coefficient may be 0.024 to 0.033 at 25° C.

[0113] As described above, the display device 10 involved in the embodiment can apply a composite component in various ways in front of and / or behind the cover window 220. For example, the composite component can be applied instead of the cover window protective layer and / or the impact absorbing layer. The composite component involved in the embodiment can have a thermal expansion coefficient, energy storage elastic modulus, loss elastic modulus and loss coefficient that can be applied to a foldable display device, so that when the display device 10 is folded, pressure can be eliminated to prevent cracks from occurring, and the impact resistance characteristics can be improved.

[0114] The following describes a method for manufacturing the display device. The composite member 400 according to one embodiment can be manufactured by a simple method described below, and thus formed on the cover window 220 of the display device 10. The following describes the manufacturing process of the composite member 400, and the material and thickness have been described, so the description is omitted.

[0115] Figures 9 to 11 The present invention is a cross-sectional view showing a method for manufacturing a display device according to an embodiment of the present invention in steps.

[0116] Reference Fig. 9 and Fig.10 The display device 10 according to an embodiment may be manufactured by forming the composite component 400 and bonding the composite component 400 to the display panel 100 .

[0117] First, the composite component 400 can be manufactured by preparing a base layer 410 and forming a resin layer 420 on the base layer 410. Specifically, the base layer 410 is prepared, and a resin 415 is applied on one surface of the base layer 410. The resin 415 can be in a solution state for manufacturing the above-mentioned resin layer 420. The resin 415 can be applied on the base layer 410 by a solution process such as inkjet printing, slit coating, screen printing, spin coating, etc. After the coating process of the resin 415, it is dried by heat treatment to form the resin layer 420. Therefore, the composite component 400 with the resin layer 420 formed on the base layer 410 can be formed.

[0118] Next, refer to Fig.11 , the display device 10 to which the previously manufactured composite member 400 is attached is prepared. The display device 10 may be in a state where the impact absorbing layer 230 and the cover window 220 disposed toward the front from the display panel 100 are combined by the first combining member 251 and the second combining member 252. Next, the previously manufactured composite member 400 is aligned and bonded to the cover window 220 of the display device 10 to manufacture the display device 10.

[0119] A conventional display device 10 uses an adhesive such as a pressure-sensitive adhesive (PSA) to bond a layer in front of the display panel 100. The process using the adhesive can be implemented in the following manner, that is, a film-shaped adhesive is laminated on an adherend for bonding, and then the adhesive is laminated on the adhesive. However, since the lamination process is performed twice, the process may become complicated. In the above-mentioned present embodiment, a resin layer 420 acting as an adhesive can be applied to a base layer 410 as an adhesive to form a composite component 400 and joined to a cover window 220 as an adherend, thereby enabling simple manufacturing. Therefore, the process can be simplified to reduce manufacturing costs and improve productivity.

[0120] The above-mentioned embodiment will be described in more detail below through experimental examples.

[0121] <Experimental Example 1: Measurement of Thermal Expansion Coefficient of Composite Parts>

[0122] As Comparative Example 1, a single PET film having a thickness of 50 μm was prepared.

[0123] As Comparative Example 2, a siloxane-based resin was applied onto a PET film having a thickness of 50 μm to form a resin layer having a thickness of 50 μm.

[0124] As Comparative Example 3, a siloxane-based resin was applied onto a PET film having a thickness of 75 μm to form a resin layer having a thickness of 40 μm.

[0125] As Example 1, a siloxane-based resin was applied onto a PET film having a thickness of 65 μm to form a resin layer having a thickness of 30 μm.

[0126] As Example 2, a siloxane-based resin was applied onto a PET film having a thickness of 75 μm to form a resin layer having a thickness of 20 μm.

[0127] As Example 3, a siloxane-based resin was applied onto a PET film having a thickness of 75 μm to form a resin layer having a thickness of 25 μm.

[0128] As Example 4, a siloxane-based resin was applied onto a PET film having a thickness of 75 μm to form a resin layer having a thickness of 35 μm.

[0129] After preparing three samples each according to Comparative Examples 1 to 3 and Examples 1 to 4, the thermal expansion coefficient was measured by using a TMA (Thermo Mechanical Analyzer) to measure the change in the range of -40°C to 60°C from -50°C to 150°C at a temperature increase of 10°C per minute. The results are shown in Table 1 below (the unit of thermal expansion coefficient is ppm / °C.)

[0130] [Table 1]

[0131] sample# #1 #2 #3 average value Comparative Example 1 14.95 15.11 15.20 15.09 Comparative Example 2 65.10 58.60 43.77 55.82 Comparative Example 3 55.9 67.8 52.6 58.7 Example 1 42.2 35.8 37.0 38.3 Example 2 29.8 34.1 37.2 33.7 Example 3 30.02 33.46 35.45 32.98 Example 4 39.8 43.9 45.2 42.9

[0132] <Experimental Example 2: Pen drop test and low temperature folding test of display device>

[0133] In Experimental Example 1, the composite component samples manufactured according to Comparative Examples 1 to 3 and Examples 1 to 4 were combined to manufacture the following Figure 3 A sample display device is shown.

[0134] The pen drop test is performed by dropping a pen with a diameter of 0.7π and a weight of 5.35g onto the surface of a display device sample fixed on granite to check the height of the bright spot. The pen drop height is measured by moving the pen drop height by 0.1cm in a range of 0.5cm to 12cm. The pen is dropped repeatedly, and the height at which the bright spot is finally generated is recorded. Fig.12 Indicates the result. Fig.12 : is a graph showing the pen drop test results of the display device samples according to Experimental Example 1.

[0135] In the low temperature folding test, the display device sample was folded and unfolded 3000 times at a temperature of -20°C, and then observed to see if cracks occurred on the surface. The case where cracks occurred was indicated as NG, and the case where no cracks occurred was indicated as OK. Table 2 shows the results.

[0136] [Table 2]

[0137] Test Results Comparative Example 1 OK Comparative Example 2 NG Comparative Example 3 NG Example 1 OK Example 2 OK Example 3 OK Example 4 OK

[0138] Refer to Table 1, Table 2 and Fig.12 The composite component involved in Comparative Example 1 and the display device including the same showed an average thermal expansion coefficient of 15.09ppm / ℃, which was low, and no cracks were generated in the folding test, but the pen drop test showed a low coefficient of 6cm. The composite component involved in Comparative Example 2 and the display device including the same showed an average thermal expansion coefficient of 55.82ppm / ℃, which was high by 11cm in the pen drop test, but cracks were generated in the folding test. In addition, the composite component involved in Comparative Example 3 and the display device including the same showed an average thermal expansion coefficient of 58.7ppm / ℃, which was high by 10cm in the pen drop test, but cracks were generated in the folding test.

[0139] In contrast, in the case of Examples 1 to 4, the average thermal expansion coefficients were 38.3 ppm / °C, 33.7 ppm / °C, 32.98 ppm / °C and 42.9 ppm / °C, the pen drop test was 7 cm to 9 cm, and no cracks were generated in the folding test.

[0140] The results confirm that the composite components involved in Examples 1 to 4 exhibit a thermal expansion coefficient of 20ppm / °C to 45ppm / °C, and the display device including the composite components has excellent impact resistance and shows folding test results suitable for use in foldable display devices.

[0141] <Experimental Example 3: Measurement of storage elastic modulus, loss elastic modulus and loss coefficient of composite parts>

[0142] The composite component samples of Comparative Example 1, Comparative Example 2 and Example 3 manufactured in Experimental Example 1 were used to measure the storage modulus and loss modulus at temperatures of -20°C, 25°C, 60°C and 80°C, and the loss coefficient was calculated based on the storage modulus and loss modulus. The results are shown in Table 3. As a method for measuring the storage modulus and loss modulus, a dynamic mechanical analyzer (DMA) was used to measure the temperature from -50°C to 150°C at a rate of 3°C per minute (the units of the storage modulus and loss modulus are GPa).

[0143] [Table 3]

[0144]

[0145] Referring to Table 3, the composite component according to Example 3, which exhibited excellent characteristics in the pen drop test and the folding test in Experimental Examples 1 and 2, may have a storage modulus of 2 GPa to 3.5 GPa, a loss modulus of 0.04 to 0.12, and a loss coefficient of 0.02 to 0.035.

[0146] The composite component involved in one embodiment can have the above-mentioned physical properties of thermal expansion coefficient, storage elastic modulus, loss elastic modulus and loss coefficient, so that it has excellent impact resistance and can eliminate pressure when folded, and is suitable for use in a foldable display device.

[0147] The embodiments of the present invention are described above with reference to the accompanying drawings, but those skilled in the art should be able to understand that the present invention can be implemented in other specific forms without changing the technical concept or essential features. Therefore, it should be understood that the embodiments described above are illustrative in all aspects and are not restrictive.

Claims

1. A display device, characterized in that: include: A display panel, including a front side; as well as The front stacked structure is arranged on the one side of the display panel. The front stacked structure includes: a cover window; and a first composite component, which is arranged on the cover window. The first composite component includes: a base layer; and a resin layer disposed on the base layer. The thermal expansion coefficient of the first composite member is 20 ppm / °C to 45 ppm / °C in a temperature range of -40°C to 60°C.

2. The display device according to claim 1, characterized in that The thickness of the base layer is 65 μm to 75 μm.

3. The display device according to claim 1, characterized in that The thickness of the resin layer is 20 μm to 35 μm.

4. The display device according to claim 1, characterized in that The storage modulus of the first composite member is 2.7 GPa to 2.9 GPa at 25°C.

5. The display device according to claim 1, characterized in that The loss modulus of elasticity of the first composite member is 0.07 GPa to 0.09 GPa at 25°C.

6. The display device according to claim 1, characterized in that: The loss coefficient of the first composite member is 0.024 to 0.033 at 25°C.

7. A display device, characterized in that: include: A display panel, including a front side; as well as The front stacked structure is arranged on the one side of the display panel. The front stacked structure includes: a cover window; a first composite component disposed on the cover window; and a second composite component disposed between the cover window and the display panel. The first composite component and the second composite component respectively include: a base layer; a resin layer disposed on the base layer; The storage modulus of each of the first composite member and the second composite member is 2.7 GPa to 2.9 GPa at 25°C.

8. The display device according to claim 7, characterized in that: The thermal expansion coefficient of each of the first composite member and the second composite member is 20 ppm / °C to 45 ppm / °C in a temperature range of -40°C to 60°C.

9. The display device according to claim 7, characterized in that: The loss modulus of each of the first composite member and the second composite member is 0.07 GPa to 0.09 GPa at 25°C.

10. The display device according to claim 7, characterized in that: The loss coefficient of each of the first composite member and the second composite member is 0.024 to 0.033 at 25°C.

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