Display device

Abstract

Disclosed is a display device including a display module having at least one folding area, a first film disposed on the display module and having a first modulus, a second film disposed on the first film farther from the display module than the first film and having a second modulus smaller than the first modulus, and a third film disposed on the second film farther from the display module than the second film and having a third modulus smaller than the second modulus. The third modulus is equal to or smaller than about one sixth of the first modulus.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2020-0014914, filed on February 7, 2020, and Korean Patent Application No. 10-2020-0147856, filed on November 6, 2020, the disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0003] This disclosure relates to a display device with enhanced folding properties and increased impact resistance. Background Technology

[0004] Display devices display various images on their display screens, such as their assigned screens, to provide information to users. For example, flexible display devices have recently been developed for mobile devices to provide much larger screens that include flexible display panels that can be folded. Unlike rigid display devices, flexible display devices can be foldable, rollable, stretchable, and / or bendable. Flexible display devices that can deform into various shapes can be carried, regardless of the existing screen size of the flexible display device, thereby improving user convenience. In addition to flexibility, good impact resistance is also expected for flexible display devices. Summary of the Invention

[0005] An exemplary embodiment of this disclosure provides a display device with enhanced folding properties and increased impact resistance.

[0006] According to an example embodiment of this disclosure, a display device may include: a display module having at least one folded region; a first film disposed on the display module and having a first modulus; a second film disposed on the first film, further away from the display module than the first film, and having a second modulus less than the first modulus; and a third film disposed on the second film, further away from the display module than the second film, and having a third modulus less than the second modulus. The third modulus may be equal to or less than approximately one-sixth of the first modulus.

[0007] In an exemplary embodiment of this disclosure, the third modulus may be equal to or greater than about 1.5% of the first modulus and equal to or less than about 16.67% of the first modulus.

[0008] In an exemplary embodiment of this disclosure, the second modulus may be equal to or greater than about 50% of the first modulus and less than about 100% of the first modulus.

[0009] In exemplary embodiments of this disclosure, the first membrane may be a composite material comprising one or more of polyimide (PI), aromatic polyamide, glass fiber, chopped glass filaments, and cellulose fiber.

[0010] In exemplary embodiments of this disclosure, the second film may include polyethylene terephthalate (PET), acrylic acid, polycarbonate (PC), polyethylene naphthalate (PEN), or triacetyl cellulose (TAC).

[0011] In exemplary embodiments of this disclosure, the third membrane may include polyamide (PA), polymethyl methacrylate (PMMA), polyether block amide (PEBA) polymers, silicone polymers, or urethane polymers.

[0012] In an exemplary embodiment of this disclosure, the thickness of the third film may be greater than the thickness of the first film and the thickness of the second film. The thickness of the first film and the thickness of the second film may be the same as each other.

[0013] In an exemplary embodiment of this disclosure, the display device may further include: a first adhesive layer inserted between the display module and the first film; a second adhesive layer inserted between the first film and the second film; and a third adhesive layer inserted between the second film and the third film.

[0014] In exemplary embodiments of this disclosure, the thicknesses of the first adhesive layer, the second adhesive layer, and the third adhesive layer may be the same as each other. The thickness of the third adhesive layer may be less than the thicknesses of the first adhesive layer and the second adhesive layer.

[0015] In an exemplary embodiment of this disclosure, at a predetermined temperature, the adhesive force of the second adhesive layer may be less than the adhesive force of the first adhesive layer and the adhesive force of the third adhesive layer.

[0016] In an exemplary embodiment of this disclosure, the display device may further include: a fourth adhesive layer disposed below the display module; and a fourth film disposed below the fourth adhesive layer and having a fourth modulus less than the first modulus.

[0017] In an exemplary embodiment of this disclosure, the display device may further include: a fifth adhesive layer disposed beneath the fourth film; and a fifth film disposed beneath the fifth adhesive layer and having a fifth modulus less than the first modulus.

[0018] In an exemplary embodiment of this disclosure, the fifth modulus may be less than the fourth modulus. The thickness of the fifth film may be greater than the thickness of the fourth film.

[0019] In exemplary embodiments of this disclosure, each of the first membrane and the second membrane may include a membrane that satisfies the following conditions: a yield strain of about 1.9% to about 2.5%, a plasticity index of about 0.58 to about 1, a recovery rate of about 80% to about 100%, and a strain rate of about 0% to about 30%.

[0020] In an exemplary embodiment of this disclosure, the third membrane comprises a membrane that satisfies the following conditions: a yield strain of about 1.9% to about 2.5%, a plasticity index of about 0.58 to about 1, a recovery rate of about 80% to about 100%, and a strain rate of about 0% to about 100%.

[0021] According to an example embodiment of this disclosure, a display device may include: a display module having at least one folded region; a first film disposed on the display module and having a first modulus; a second film disposed on the first film, further away from the display module than the first film, and having a second modulus different from the first modulus; a third film disposed on the second film, further away from the display module than the second film, and having a third modulus different from the first modulus and the second modulus; a first adhesive layer interposed between the display module and the first film; a second adhesive layer interposed between the first film and the second film; and a third adhesive layer interposed between the second film and the third film. At a predetermined temperature, one or both of the adhesive forces of the second adhesive layer and the third adhesive layer may be less than the adhesive force of the first adhesive layer.

[0022] In an exemplary embodiment of this disclosure, the second modulus may be less than the first modulus. The second modulus may be greater than the third modulus. The third modulus may be equal to or greater than about 1.5% of the first modulus and equal to or less than about 16.67% of the first modulus.

[0023] In an exemplary embodiment of this disclosure, the display device may further include: a fourth film disposed below the display module and having a fourth modulus less than the first modulus; and a fifth film disposed below the fourth film and having a fifth modulus less than the fourth modulus. The thickness of the fifth film may be greater than the thickness of the fourth film.

[0024] In an exemplary embodiment of this disclosure, the thickness of the first film and the thickness of the second film may be the same as each other. The thickness of the third film may be greater than the thickness of the first film and the thickness of the second film.

[0025] In exemplary embodiments of this disclosure, the first membrane may be a composite material comprising one or more of polyimide (PI), aromatic polyamide, glass fiber, chopped glass filaments, and cellulose fiber.

[0026] In exemplary embodiments of this disclosure, the second film may include polyethylene terephthalate (PET), acrylic acid, polycarbonate (PC), polyethylene naphthalate (PEN), or triacetyl cellulose (TAC).

[0027] In exemplary embodiments of this disclosure, the third membrane may include polyamide (PA), polymethyl methacrylate (PMMA), polyether block amide (PEBA) polymers, silicone polymers, or urethane polymers.

[0028] In exemplary embodiments of this disclosure, each of the first membrane and the second membrane may include a membrane that satisfies the following conditions: a yield strain of about 1.9% to about 2.5%, a plasticity index of about 0.58 to about 1, a recovery rate of about 80% to about 100%, and a strain rate of about 0% to about 30%.

[0029] In an exemplary embodiment of this disclosure, the third membrane may include a membrane that satisfies the following conditions: a yield strain of about 1.9% to about 2.5%, a plasticity index of about 0.58 to about 1, a recovery rate of about 80% to about 100%, and a strain rate of about 0% to about 100%. Attached Figure Description

[0030] Exemplary embodiments of this disclosure will become clearer from the following detailed description taken in conjunction with the accompanying drawings:

[0031] Figure 1A A perspective view illustrating a display device according to an example embodiment of the present disclosure is shown;

[0032] Figure 1B A perspective view showing the operation state of a display device according to an example embodiment of the present disclosure is shown;

[0033] Figure 2A A perspective view illustrating a display device according to an example embodiment of the present disclosure is shown;

[0034] Figure 2B A perspective view showing the operation state of a display device according to an example embodiment of the present disclosure is shown;

[0035] Figure 3 A cross-sectional view illustrating a display device according to an example embodiment of the present disclosure is shown;

[0036] Figure 4 A cross-sectional view illustrating a display module according to an example embodiment of the present disclosure is shown;

[0037] Figure 5 A cross-sectional view illustrating a display device according to an example embodiment of the present disclosure is shown; and

[0038] Figure 6 A cross-sectional view illustrating a display device according to an example embodiment of the present disclosure is shown.

[0039] because Figure 1A , Figure 1B , Figure 2A , Figure 2B , Figures 3 to 6 The diagrams in this book are intended for illustrative purposes, therefore the elements in the diagrams are not necessarily drawn to scale. For example, some elements may be enlarged or exaggerated for clarity. Detailed Implementation

[0040] In this description, when a component (or area, layer, section, etc.) is referred to as being "on", "connected to", or "coupled to" other components, the component may be directly disposed on, directly connected to, or directly coupled to other components, or at least one intermediate component may be inserted between the component and other components.

[0041] The same reference numerals always refer to the same components.

[0042] The term “and / or” includes any and all combinations of one or more of the related listed components.

[0043] It will be understood that although the terms “first,” “second,” “third,” etc., may be used herein to describe various components, these components should not be limited by these terms. These terms are used only to distinguish one component from another. For example, a first component may be referred to as a second component without departing from the scope of this disclosure, and vice versa. Unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well.

[0044] In addition, the terms “below,” “lower,” “above,” and “upper” are used in this document to describe the relationship between one component shown in the figure and other components(s). Besides the orientations depicted in the figures, these spatially relative terms are also intended to cover different orientations of the device during use or operation.

[0045] In light of the measurement and measurement-related errors (i.e., the limitations of the measurement system) in the discussion of specific quantities, the term “about” as used herein includes the stated value and refers to an acceptable range of deviation from the specific value as determined by one of ordinary skill in the art. For example, “about” may mean within one or more standard deviations, or within ±30%, ±20%, ±10%, or ±5% of the stated value.

[0046] Unless otherwise defined, all terms used herein, including technical and scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Furthermore, unless expressly defined herein, terms as defined in a general dictionary shall be understood to have a meaning consistent with their meaning in the context of the relevant field and shall not be understood to have an idealized or overly formalized meaning.

[0047] It should be understood that the terms “comprising,” “including,” and “having” are used to describe the presence of the stated features, wholes, steps, operations, components, elements, or combinations thereof, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, components, elements, or combinations thereof.

[0048] Now, exemplary embodiments of this disclosure will be described below with reference to the accompanying drawings.

[0049] Figure 1A A perspective view of a display device according to an example embodiment of the present disclosure is shown. Figure 1B A perspective view showing the operating state of a display device according to an example embodiment of the present disclosure is shown.

[0050] Reference Figure 1A and Figure 1B The display device 1000 can be a device activated by an electrical signal. For example, the display device 1000 can be a mobile phone, tablet computer, car navigation system, game console, or wearable device such as a smartwatch, but this disclosure is not limited thereto. Figure 1A An example of a mobile phone as a display device 1000 is shown.

[0051] The display device 1000 may be a foldable display device. The display device 1000 may include a first non-foldable region 1000NF1, a foldable region 1000F, and a second non-foldable region 1000NF2, sequentially defined along a first direction DR1. For example, the foldable region 1000F may be defined between the first non-foldable region 1000NF1 and the second non-foldable region 1000NF2. The first non-foldable region 1000NF1 and the second non-foldable region 1000NF2 may each have a flat surface and may not be folded or bent. In the unfolded state, the foldable region 1000F may have a flat surface positioned on the same plane as the surfaces of the first non-foldable region 1000NF1 and the second non-foldable region 1000NF2, but the foldable region 1000F may be folded or bent to have a curved surface.

[0052] The display device 1000 can display images on an active region 1000-A. In the unfolded state, the active region 1000-A may include a surface parallel to a plane defined by a first direction DR1 and a second direction DR2. For example, the surface of the active region 1000-A may include the display surface of a first non-folded region 1000NF1, the display surface of a folded region 1000F, and the display surface of a second non-folded region 1000NF2. The thickness direction of the display device 1000 may be parallel to a third direction DR3 intersecting the first direction DR1 and the second direction DR2. Therefore, the third direction DR3 can be used to distinguish the front and rear surfaces (or top and bottom surfaces) of each component included in the display device 1000.

[0053] When the display device 1000 is folded, the first non-folded region 1000NF1 and the second non-folded region 1000NF2 allow the display surfaces of the first non-folded region 1000NF1 and the second non-folded region 1000NF2 to face each other. Therefore, when the display device 1000 is in a fully folded state, the active region 1000-A may not be exposed. This can be referred to as inward folding. However, this is merely an example, and this disclosure is not limited thereto.

[0054] When the display device 1000 is folded, the first non-folded region 1000NF1 and the second non-folded region 1000NF2 allow the display surfaces of the first non-folded region 1000NF1 and the second non-folded region 1000NF2 to face each other in opposite directions, for example, facing outwards. Therefore, in the folded state, the active region 1000-A can be exposed to the outside. This can be referred to as outward folding. The display device 1000 can become either inward folding or outward folding.

[0055] Figure 2A A perspective view of a display device according to an example embodiment of the present disclosure is shown. Figure 2B A perspective view showing the operating state of a display device according to an example embodiment of the present disclosure is shown.

[0056] Reference Figure 2A and Figure 2BThe display device 1000a may be a multi-foldable display device. The display device 1000a may include a first non-foldable region 1000NF1a, a first foldable region 1000F1, a second non-foldable region 1000NF2a, a second foldable region 1000F2, and a third non-foldable region 1000NF3a, sequentially defined along a first direction DR1. For example, the display device 1000a may include multiple foldable regions 1000F1 and 1000F2. The first non-foldable region 1000NF1a, the second non-foldable region 1000NF2a, and the third non-foldable region 1000NF3a may each have a flat surface and may not be folded or bent. In the unfolded state, the first foldable region 1000F1 and the second foldable region 1000F2 may each have a flat surface located on the same plane as the surface of the first non-foldable region 1000NF1a, the second non-foldable region 1000NF2a, and the third non-foldable region 1000NF3a. However, the first foldable region 1000F1 and the second foldable region 1000F2 may each be folded or bent to have a curved surface.

[0057] The display device 1000a can display images on the first active region 1000-A1 and the second active region 1000-A2. Figure 2B An example is shown where the first active region 1000-A1 and the second active region 1000-A2 are not contiguous with each other, but this disclosure is not limited thereto. For example, the first active region 1000-A1 and the second active region 1000-A2 may be contiguous with each other.

[0058] The boundary between the first active region 1000-A1 and the second active region 1000-A2 can overlap with the first folded region 1000F1, and the second folded region 1000F2 can be defined on the second active region 1000-A2. The first folded region 1000F1 can be folded outward, and the second folded region 1000F2 can be folded inward. Therefore, when the display device 1000a is folded, the second non-folded region 1000NF2a and the third non-folded region 1000NF3a can allow the display surfaces of the second non-folded region 1000NF2a and the third non-folded region 1000NF3a to face each other, while the display surface of the first non-folded region 1000NF1a can face outward. Therefore, when the display device 1000a is in a fully folded state, the second active region 1000-A2 can be unexposed, while the first active region 1000-A1 is exposed.

[0059] like Figure 1BAs shown and as described above, the display device 1000 may be a foldable display device including a foldable region 1000F defined between a first non-foldable region 1000NF1 and a second non-foldable region 1000NF2. Furthermore, as... Figure 2B As shown and as described above, the display device 1000a can be a multi-foldable display device including multiple folding regions 1000F1 and 1000F2. The display module 100 (see...) Figure 3 It may include at least one folded area, such as a folded area 1000F in display device 1000, or multiple folded areas 1000F1 and 1000F2 in display device 1000a.

[0060] Figure 3 A cross-sectional view illustrating a display device according to an example embodiment of the present disclosure is shown.

[0061] Reference Figure 3 The display device 1000 may include a display module 100; a first adhesive layer 210, a second adhesive layer 220, a third adhesive layer 230, a fourth adhesive layer 240 and a fifth adhesive layer 250; and a first film 310, a second film 320, a third film 330, a fourth film 340 and a fifth film 350.

[0062] The display module 100 can display images and detect external input. External input can be user input. User input may include, for example, user body parts, light, heat, pen input, pressure, or various other types of external input.

[0063] The display module 100 may include a display panel 110 for generating images and an input sensor 120 for acquiring coordinate information from external input.

[0064] Display panel 110 can be an emitting display panel, but is not limited to an emitting display panel. For example, display panel 110 can be an organic light-emitting display panel or a quantum dot light-emitting display panel. The emitting layer of an organic light-emitting display panel can include organic light-emitting materials. The emitting layer of a quantum dot light-emitting display panel can include quantum dots or quantum rods.

[0065] Input sensor 120 may be disposed on display panel 110. Input sensor 120 may detect external input using mutual capacitance or self-capacitance methods. For example, input sensor 120 may obtain information about external input through capacitance changes between two sensing electrodes. However, external input detection methods are not limited to the examples mentioned above.

[0066] A first adhesive layer 210 may be disposed on the display module 100. A first film 310 may be disposed on the first adhesive layer 210. For example, the first film 310 may be disposed on the display module 100, and the first adhesive layer 210 may be inserted between the first film 310 and the display module 100 to bond the first film 310 to the display module 100. A second adhesive layer 220 may be disposed on the first film 310. A second film 320 may be disposed on the second adhesive layer 220. For example, the second film 320 may be disposed on the first film 310, and the second adhesive layer 220 may be inserted between the second film 320 and the first film 310 to bond the second film 320 to the first film 310. A third adhesive layer 230 may be disposed on the second film 320. A third film 330 may be disposed on the third adhesive layer 230. For example, the third film 330 may be disposed on the second film 320, and the third adhesive layer 230 may be inserted between the third film 330 and the second film 320 to bond the third film 330 to the second film 320. The second film 320 can be further away from the display module 100 than the first film 310, and the third film 330 can be further away from the display module 100 than the second film 320. Therefore, among the first film 310, the second film 320, and the third film 330, the third film 330 can have the longest distance from the display module 100. Each of the first film 310, the second film 320, and the third film 330 can have a transmittance equal to or greater than about 85%, for example, about 90% or greater, a haze value equal to or less than about 3%, for example, about 1% or less, and a yellow index (YI) equal to or less than about 2.

[0067] A fourth adhesive layer 240 may be disposed below the display module 100. A fourth film 340 may be disposed below the fourth adhesive layer 240. The fourth adhesive layer 240 can bond the fourth film 340 to the display module 100. The fourth film 340 may be a protective film protecting the bottom surface of the display module 100, and may be, for example, a colored polyimide (PI) film. A fifth adhesive layer 250 may be disposed below the fourth film 340. A fifth film 350 may be disposed below the fifth adhesive layer 250. The fifth adhesive layer 250 can bond the fifth film 350 to the fourth film 340. The fifth film 350 may be a protective film protecting the bottom surface of the display module 100, and may be a padding layer including, for example, sponge, foam, or urethane resin.

[0068] The first film 310, the second film 320, and the third film 330 may have moduli that decrease with increasing distance from the display module 100. For example, the first film 310 may have a first modulus, the second film 320 may have a second modulus, and the third film 330 may have a third modulus. The second modulus may be less than the first modulus, and the third modulus may be less than the second modulus. For example, the first modulus may be in the range of about 6500 MPa to about 10000 MPa, the second modulus may be in the range of about 3500 MPa to about 5000 MPa, and the third modulus may be in the range of about 600 MPa to about 1000 MPa.

[0069] The fourth membrane 340 may have a fourth modulus, and the fifth membrane 350 may have a fifth modulus. The fourth modulus may be less than the first modulus, and the fifth modulus may be less than the fourth modulus. For example, the fifth modulus may be less than the first modulus.

[0070] In this description, the term "modulus" can refer to a value measured by a Universal Testing Machine (UTM) using a sample approximately 10 mm wide and a gauge length of approximately 50 mm. For example, the term "modulus" can be a value obtained at approximately 0.025% to approximately 0.5% of the stress-strain curve of a sample calibrated in a UTM. The term "modulus" can also be referred to as the elastic modulus, Young's modulus, elastic constant, or elastic modulus.

[0071] The first membrane 310 can be a composite material including, for example, one or more of polyimide (PI), aramid, glass fiber, chopped glass filaments and cellulose fiber, and therefore can have a high modulus.

[0072] The second film 320 may comprise, for example, polyethylene terephthalate (PET), acrylic acid, polycarbonate (PC), polyethylene naphthalate (PEN), or triacetyl cellulose (TAC), and therefore may have a medium modulus. For example, the second film 320 may have a second modulus lower than the first modulus of the first film 310. When the second film 320 comprises polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), an extrusion process can be used to control the modulus along the machine direction and transverse direction. When the second film 320 comprises polycarbonate (PC) or triacetyl cellulose (TAC), a casting process can be used to form the second film 320.

[0073] The third membrane 330 may comprise, for example, a polyamide (PA), polymethyl methacrylate (PMMA), a polyether block amide (PEBA) polymer, a silicone polymer, or a urethane polymer, and therefore may have a low modulus. For example, the third membrane 330 may have a third modulus that is lower than the second modulus of the second membrane 320. In exemplary embodiments of this disclosure, the third membrane 330 may comprise an elastomer to provide a low modulus.

[0074] Polyether block amide (PEBA) polymers are block copolymers in which the soft portion comprises polyether segments and the rigid portion comprises polyamide blocks.

[0075] When the third membrane 330 comprises a polyether block amide (PEBA) polymer, the third modulus of the third membrane 330 can be adjusted by the ratio between the soft portion and the rigid portion.

[0076] Urea-based polymers may include polyols, isocyanates, and chain extenders. Polyols may include one or more of, for example, polyethers, polyesters, polycarbonates, polybutadiene, and acrylic acids. Isocyanates may include one or more of, for example, methylene diphenyl diisocyanate (MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and 1,4-cyclohexane diisocyanate (CDI). Chain extenders may include one or more of, for example, glycols, diamines, triols, tetraols, and amino alcohols.

[0077] When the third membrane 330 includes urethane polymers, the third modulus of the third membrane 330 can be adjusted by the ratio between the polyol, isocyanate and chain extender.

[0078] The silicone polymer can be a linear polymer such as polydimethylsiloxane. When the third membrane 330 includes a silicone polymer, the third modulus of the third membrane 330 can be adjusted based on the degree of entanglement in the molecular structure of the linear polymer.

[0079] Table 1 below lists the second modulus of the second membrane 320 and the third modulus of the third membrane 330. When the first modulus of the first membrane 310 is approximately 6 GPa, the second modulus of the second membrane 320 and the third modulus of the third membrane 330 satisfy the minimum strain condition and the buckling count criterion. The moduli listed in Table 1 below satisfy the minimum strain condition in each of the three simulations performed. Although a first modulus of approximately 6 GPa for the first membrane 310 was used in the simulations, any other suitable high modulus can be used for the first membrane 310. For example, in the exemplary embodiments of this disclosure, the first modulus of the first membrane 310 can be in the range of approximately 5 GPa to approximately 10 GPa.

[0080] When the length change is less than about 2%, the minimum strain condition can be considered met, and when the number of buckles is less than about 20, the buckling count criterion can be considered met.

[0081] Referring to Table 1, when the first modulus of the first membrane 310 is about 6 GPa, the minimum strain condition and buckling count criterion can be satisfied when the second modulus of the second membrane 320 is in the range of about 3.5 GPa to about 5 GPa and when the third modulus of the third membrane 330 is in the range of about 1 GPa or less.

[0082] [Table 1]

[0083]

[0084]

[0085] Table 2 below lists whether the strain condition and flexibility test are satisfied based on the third modulus of the third membrane 330 and the thickness of each of the first membrane 310, second membrane 320, and third membrane 330. The comparative example shows the test results when the first modulus of the first membrane 310 is about 6 GPa, the second modulus of the second membrane 320 is about 4 GPa, and the third modulus of the third membrane 330 is about 1.4 GPa. According to the comparative example, the third modulus of the third membrane 330 can be about 23.33% of the first modulus of the first membrane 310. As shown in Table 2, the comparative example does not satisfy both the minimum strain condition and the flexibility test. The embodiment shows the test results when the first modulus of the first membrane 310 is about 6 GPa, the second modulus of the second membrane 320 is about 4 GPa, and the third modulus of the third membrane 330 is about 800 MPa. According to the embodiment, the third modulus of the third membrane 330 can be about 13.33% of the first modulus of the first membrane 310. As shown in Table 2, the embodiment satisfies both the minimum strain condition and the flexibility test.

[0086] [Table 2]

[0087]

[0088] According to exemplary embodiments of this disclosure, a second modulus and a third modulus can be determined to satisfy the minimum strain condition and the buckling count criterion. For example, the second modulus may be equal to or greater than about 50% of the first modulus and less than about 100% of the first modulus, and the third modulus may be equal to or greater than about 1.5% of the first modulus and equal to or less than about 16.67% of the first modulus. In exemplary embodiments of this disclosure, the third modulus may be equal to or less than one-sixth of the first modulus. For example, when the first modulus is about 6.5 GPa, the second modulus may be equal to or greater than about 3.5 GPa and less than about 6.5 GPa, and the third modulus may be from about 0.1 GPa to about 1.08 GPa. For example, when the first modulus is about 7 GPa, the third modulus may be about 1.2 GPa or less, or may be from about 0.11 GPa to about 1.17 GPa.

[0089] When the third modulus is greater than approximately 16.67% of the first modulus, the display device 1000 may not meet the minimum strain condition or flexibility test.

[0090] The fourth modulus can be about 30% of the first modulus, and the fifth modulus can be about 1.5% of the first modulus. The fourth modulus can be equal to or less than about 2 GPa, and the fifth modulus can be equal to or less than about 0.1 GPa. The fourth modulus of the fourth film 340 and the fifth modulus of the fifth film 350 below the display module 100 can decrease with increasing distance from the display module 100. The fourth film 340 and the fifth film 350 can be protective films protecting the bottom surface of the display module 100. In addition, according to an exemplary embodiment of this disclosure, the fifth film 350 with a low modulus can be disposed in an external position, such that even when the fifth film 350 deforms in thickness, the flexibility properties can be enhanced due to the reduction of shape changes (e.g., thickness changes) of the other layer adjacent to the fifth film 350.

[0091] Each of the first adhesive layer 210, the second adhesive layer 220, the third adhesive layer 230, the fourth adhesive layer 240, and the fifth adhesive layer 250 may include a common adhesive or glue. For example, each of the first adhesive layer 210, the second adhesive layer 220, the third adhesive layer 230, the fourth adhesive layer 240, and the fifth adhesive layer 250 may be a transparent adhesive component, such as, for example, a pressure-sensitive adhesive (PSA) film, an optically clear adhesive (OCA) film, or an optically clear resin (OCR).

[0092] The first adhesive layer 210, second adhesive layer 220, third adhesive layer 230, fourth adhesive layer 240, and fifth adhesive layer 250 may comprise adhesives or glues with the same physical properties. Alternatively, at least one of the first adhesive layer 210, second adhesive layer 220, third adhesive layer 230, fourth adhesive layer 240, and fifth adhesive layer 250 may have physical properties different from those of the other adhesive layers. For example, at least one of the first adhesive layer 210, second adhesive layer 220, third adhesive layer 230, fourth adhesive layer 240, and fifth adhesive layer 250 may have an adhesive strength different from that of the other adhesive layers.

[0093] In an exemplary embodiment of this disclosure, at a predetermined temperature (hereinafter also referred to as a pre-determined temperature), the second adhesive layer 220 may have an adhesive force less than that of the other adhesive layers 210, 230, 240, and 250. Here, the predetermined temperature is the temperature used in the rework process. Depending on the rework process used, it is typically at an elevated temperature, but not at a temperature too high to damage the device being reworked. In this case, when the rework process is performed, the second film 320, the third adhesive layer 230, and the third film 330 of the assembly disposed on the second adhesive layer 220 can be easily separated from the first film 310. Alternatively, at a predetermined temperature, the third adhesive layer 230 may have an adhesive force less than that of the other adhesive layers 210, 220, 240, and 250. In this case, when the rework process is performed, the third film 330 of the assembly disposed on the third adhesive layer 230 can be easily separated from the second film 320. Furthermore, at a certain temperature, both the second adhesive layer 220 and the third adhesive layer 230 may have an adhesive force that is less than that of the other adhesive layers 210, 240, and 250. In this case, when a rework process is performed, the second film 320 can be easily separated from the first film 310 and / or the third film 330 can be easily separated from the second film 320. In the exemplary embodiments of this disclosure, at a certain temperature, one or both of the adhesive forces of the second adhesive layer 220 and the third adhesive layer 230 may be less than the adhesive force of the first adhesive layer 210.

[0094] Despite the rework process, the first film 310 can remain attached to the display module 100 because the adhesive force of the first adhesive layer 210 is greater than that of the second adhesive layer 220 and the third adhesive. Therefore, the first film 310 can protect the display module 100 even during the rework process.

[0095] The first adhesive layer 210, the second adhesive layer 220, and the third adhesive layer 230 may each have the same first thickness 210t, second thickness 220t, and third thickness 230t. For example, the first thickness 210t, second thickness 220t, and third thickness 230t may each be approximately 50 μm. The fourth adhesive layer 240 and the fifth adhesive layer 250 may each have a fourth thickness 240t and a fifth thickness 250t, each of which is smaller than any one of the first thickness 210t, second thickness 220t, and third thickness 230t. For example, the fourth thickness 240t and fifth thickness 250t may each be approximately 25 μm. Alternatively, the first thickness 210t of the first adhesive layer 210 may be different from the second thickness 220t of the second adhesive layer 220 and the third thickness 230t of the third adhesive layer 230. For example, each of the first thickness 210t and the second thickness 220t can be about 50 μm, and the third thickness 230t can be about 25 μm (see...). Figure 5 ).

[0096] The first membrane 310 may have the same first thickness 310t as the second thickness 320t of the second membrane 320. For example, the first thickness 310t and the second thickness 320t may each be equal to or less than about 40 μm, for example, about 40 μm. The third membrane 330 may have a third thickness 330t greater than each of the first thickness 310t and the second thickness 320t. For example, the third thickness 330t may be in the range of about 50 μm to about 100 μm, for example, about 75 μm.

[0097] According to an example embodiment of this disclosure, since the third membrane 330, which has the smallest modulus among the first membrane 310 to the third membrane 330, has a third thickness 330t greater than all the other thicknesses of the different layers, it is possible to increase impact resistance without reducing flexibility properties.

[0098] Unlike the exemplary embodiments of this disclosure, where the third film 330 is disposed between the first film 310 and the second film 320, when the display device 1000 is folded and the thickness of the third film 330 changes, the two adhesive layers in contact with the third film 330 may deform in thickness. This can lead to defects such as wrinkles, which may be visible to the user. In contrast, according to the exemplary embodiments of this disclosure, the third film 330 with a low modulus can be disposed in an external position, such that even when the third film 330 deforms in thickness, the flexibility properties can be enhanced due to the reduced shape change (e.g., thickness change) of the other layer adjacent to the third film 330.

[0099] The fourth thickness 340t of the fourth film 340 can be less than the first thickness 310t. For example, the fourth thickness 340t can be about 25 μm. For example, the fourth thickness 340t can be about 30 μm. The fifth thickness 350t of the fifth film 350 can be greater than the fourth thickness 340t. For example, the fifth thickness 350t can be about 100 μm. The fifth film 350 can have a lower modulus and a greater thickness and can be positioned at the lower outer part of the display device 1000 to protect the bottom surface of the display module 100 without reducing its flexibility.

[0100] According to an example embodiment of this disclosure, at least three films, such as a first film 310, a second film 320, and a third film 330, can be provided on the display module 100, thereby improving impact resistance. Furthermore, the modulus of the first film 310, the second film 320, and the third film 330 can gradually decrease with increasing distance from the display module 100. Therefore, the display device 1000 can enhance its folding properties. In this description, the expression "enhanced folding properties" can mean that the display device 1000 is foldable with a small radius of curvature.

[0101] According to exemplary embodiments of this disclosure, the enhancement of the physical properties of the first membrane 310, the second membrane 320, and the third membrane 330 can improve surface pressing and shape deformation. Physical properties may include, for example, modulus, yield strain, plastic deformation index, recovery rate, and strain rate.

[0102] The physical properties of the first membrane 310, the second membrane 320, and the third membrane 330 can be changed by controlling temperature, humidity, and / or time. For example, the physical properties can be controlled by controlling humidity and time at a temperature equal to or greater than the glass transition temperature (Tg) of each of the first membrane 310, the second membrane 320, and the third membrane 330.

[0103] Table 3 below lists the changes in physical properties caused by controlling the temperature, humidity, and time of each of the first membrane 310, the second membrane 320, and the third membrane 330.

[0104] [Table 3]

[0105]

[0106] Yield strain can refer to the point at which the membrane reaches the limit of its elastic behavior and the point at which its plastic behavior begins. The plasticity exponent can be defined as the ratio between the elastic modulus and the plastic modulus. For example, the plastic modulus can be defined as the modulus at the point where the membrane exceeds its elastic limit, such as the modulus at about 2.5% or the modulus at about 2.25% to about 2.75%. The recovery ratio can refer to a proportional value representing the degree of recovery of the membrane after yield strain and cyclic estimation. Cyclic estimation can refer to, for example, thousands or tens of thousands of times the membrane is repeatedly folded and unfolded per second in a single cycle. The strain ratio can refer to a proportional value expressing the degree of stretching of the membrane when it is stretched at a constant strain for a specific duration.

[0107] Commonly used measuring equipment can be used to measure modulus, yield strain, plasticity index, recovery ratio, and strain ratio. For example, a universal testing machine (UTM) can be used to measure physical properties.

[0108] One or both of the first membrane 310 and the second membrane 320 may include a membrane with a yield strain of about 1.9% to about 2.5%, a plasticity index of about 0.58 to about 1, a recovery rate of about 80% to about 100%, and a strain ratio of about 0% to about 30%, and the third membrane 330 may include a membrane with a yield strain of about 1.9% to about 2.5%, a plasticity index of about 0.58 to about 1, a recovery rate of about 80% to about 100%, and a strain ratio of about 0% to about 100%. Since the third membrane 330 has a third modulus that is less than the first modulus of the first membrane 310 and the second modulus of the second membrane 320, the third membrane 330 may include a membrane with a high strain ratio. In Table 3 above, the first membrane (A), the first membrane (A'), and the second membrane (B') may be membranes that satisfy specific physical properties.

[0109] Table 4 below lists the module properties with the first film 310, the second film 320, and the third film 330 attached to the display module 100. Comparative examples illustrate combinations that failed the test, while embodiments illustrate combinations that passed the test.

[0110] [Table 4]

[0111]

[0112] Pressing can be used to assess defects caused by pressing on the surface of the display device 1000. For example, an artificial nail clipper can press a specific load onto the surface of the display device 1000 to determine if the display device 1000 is defective. The values ​​listed in Table 4 can refer to the minimum load at which pressing defects can be visually identified. It can be estimated that a high level of reliability can be achieved by increasing the minimum load from which pressing defects are visible. The benchmark value for a good product that exceeds pressing defects can be equal to or greater than about 2000 gf (gram force), for example, about 2400 gf or higher.

[0113] The deformation angle can be measured from the unfolded state of the display device 1000. After the display device 1000 is folded, it has maintained the folded state for a specific duration under certain conditions. For example, certain conditions could be indoor humidity at indoor temperature, or high humidity at high temperature.

[0114] The display device 1000 can be folded into a folded state, thus having a curvature radius of approximately 1 mm, and the specific duration is approximately 24 hours. The indoor temperature can be approximately 25 degrees Celsius, the indoor humidity can be approximately 40%, the high temperature can be approximately 60 degrees Celsius, and the high humidity can be approximately 90%.

[0115] The distortion angle can be defined as the angle between the reference plane and the floating plane of the display device 1000. For example, when the distortion angle is zero, it can mean that the display device 1000 has a completely flat state. When the distortion angle is close to zero, the distortion angle property can be estimated as excellent.

[0116] The first deformation angle can refer to the angle when the display device is unfolded, and can also be called the instantaneous deformation angle. A good product reference value for the first deformation angle can be equal to or less than approximately 45 degrees.

[0117] The second deformation angle can refer to the angle measured from the unfolded state of the display device 1000, after which the folded display device 1000 has been unfolded and has maintained this unfolded state for a specific duration, such as approximately 24 hours. The second deformation angle can be referred to as the permanent deformation angle. A good product reference value for the second deformation angle can be equal to or less than approximately 18 degrees, for example, approximately 10 degrees or less.

[0118] The fold depth can be obtained from optical equipment, which measures the folded area (see...). Figure 1AThe depth of the wrinkles appearing on the display device 1000 (F). For example, the wrinkle depth can be the measured depth of wrinkles that appear after the display device 1000 has maintained its folded state for a specific duration under certain conditions. The certain conditions can be indoor humidity at indoor temperature, or high humidity at high temperature.

[0119] For example, the wrinkle depth can be the measured depth of the wrinkles that appear when the display device 1000 unfolds after it has been held in a folded state with a radius of curvature of approximately 1 mm for approximately 24 hours. The indoor temperature can be approximately 25 degrees Celsius, the indoor humidity can be approximately 40%, the high temperature can be approximately 60 degrees Celsius, and the high humidity can be approximately 90%. A good product reference value for the wrinkle depth can be equal to or less than approximately 20 μm.

[0120] When the first membrane 310, the second membrane 320, and the third membrane 330 undergo thermal analysis, surface analysis, or chemical analysis, it may be possible to determine whether further treatment to enhance their physical properties is necessary. Thermal analysis can be performed using a thermal analyzer such as DSC or DMA to analyze the thermal properties of the membranes. Additionally, thermal analysis can analyze changes in physical properties such as crystallization temperature (Tc) and glass transition temperature (Tg) caused by the temperature parameters of the membranes. Surface and chemical analyses can be performed using equipment such as TEM, XPS, or CV to analyze structural changes, compositional comparisons, changes in redox reactions, and surface oxidation caused by temperature / humidity.

[0121] Figure 4 A cross-sectional view illustrating a display module according to an example embodiment of the present disclosure is shown.

[0122] Reference Figure 4 The display module 100 may include a display panel 110 and an input sensor 120.

[0123] Display panel 110 can be a component for generating images. Display panel 110 can be an emitting display panel. For example, display panel 110 can be an organic light-emitting display panel or a quantum dot light-emitting display panel. Input sensor 120 can be disposed on display panel 110 and can detect external input applied from the outside. External input can be user input. User input can include, for example, user body parts, light, heat, pen, pressure, or various other types of external input.

[0124] The display panel 110 and the input sensor 120 can be formed in a continuous process. In this case, it can be expressed that the input sensor 120 is directly disposed on the display panel 110. The phrase "directly disposed on" can mean that no components are disposed between the input sensor 120 and the display panel 110. For example, adhesive members can be disposed between the input sensor 120 and the display panel 110 without separation. For example, after the display panel 110 is formed, the input sensor 120 is formed directly on the substrate surface of the display panel 110 through a continuous process.

[0125] Instead of forming the input sensor 120 directly on the display panel 110 in a continuous process, the display panel 110 and the input sensor 120 can be coupled to each other by an adhesive component. The adhesive component can include common adhesives or glues. For example, the adhesive component can be a transparent adhesive component, such as a pressure-sensitive adhesive (PSA) film, an optically clear adhesive (OCA) film, or an optically clear resin (OCR).

[0126] The display panel 110 may include a substrate layer 110-1, multiple insulating layers, semiconductor patterns, conductive patterns, and signal lines. A coating or deposition process can form insulating layers, semiconductor layers, and conductive layers on the substrate layer 110-1. Subsequently, photolithography and etching processes can selectively pattern the insulating layers, semiconductor layers, and conductive layers. The aforementioned processes can form semiconductor patterns, conductive patterns, and signal lines included in the circuit layer 110-2 and the display element layer 110-3. Afterward, an encapsulation layer 110-4 can be formed to cover the display element layer 110-3.

[0127] The substrate layer 110-1 may include a synthetic resin film. The synthetic resin film may include a thermosetting resin. The substrate layer 110-1 may have a multilayer structure. For example, the substrate layer 110-1 may have a three-layer structure comprising a synthetic resin layer, an adhesive layer, and a synthetic resin layer stacked sequentially. The synthetic resin layer may be a polyimide resin layer, but this disclosure is not limited thereto. For example, the synthetic resin layer may include one or more of, for example, acrylic resins, methacrylic resins, polyisoprene, vinyl resins, epoxy resins, urethane resins, cellulose resins, siloxane resins, polyamide resins, and dinaphthalene-based resins. The substrate layer 110-1 may include a glass substrate or an organic / inorganic composite substrate.

[0128] At least one inorganic layer may be formed on the top surface of the substrate layer 110-1. The inorganic layer may include one or more of, for example, alumina (Al₂O₃), titanium dioxide (TiO₂), silicon dioxide (SiO₂), silicon oxynitride (SiON), zirconium oxide (ZrO₂), and hafnium oxide (HfO₂). The inorganic layer may be formed in multiple layers. Multiple inorganic layers may constitute a barrier layer and / or a buffer layer. In this example embodiment, the display panel 110 is shown to include a buffer layer BFL.

[0129] The buffer layer BFL increases the bonding strength between the substrate layer 110-1 and the semiconductor pattern, and can prevent foreign matter or moisture from penetrating through the substrate layer 110-1. The buffer layer BFL may include a silicon oxide (SiO2) layer and / or a silicon nitride (Si3N4) layer. The silicon oxide (SiO2) layer and the silicon nitride (Si3N4) layer may be stacked alternately.

[0130] A semiconductor pattern is disposed on the buffer layer BFL. The semiconductor pattern may include polycrystalline silicon (p-Si). However, this disclosure is not limited thereto, and the semiconductor pattern may include, for example, amorphous silicon (a-Si), or may include an oxide semiconductor comprising a metal oxide.

[0131] Figure 4 Only a portion of the semiconductor pattern is shown, and the semiconductor pattern can also be disposed on other regions. The semiconductor pattern can be specifically arranged above a pixel. The semiconductor pattern can have different electrical properties based on doping and can include a first region with high conductivity and a second region with low conductivity. The first region can be doped with n-type or p-type impurities. For example, n-type impurities can include, for example, phosphorus (P), arsenic (As), or antimony (Sb), and p-type impurities can include, for example, aluminum (Al), boron (B), or indium (In). A p-type transistor includes a doped region implanted with p-type impurities. Compared to the first region, the second region can be an undoped region or can be lightly doped.

[0132] The first region has a higher conductivity than the second region and is essentially used as an electrode or signal line. The second region essentially corresponds to the active region (or channel region) of a transistor. For example, a portion of the semiconductor pattern can be the active region of a transistor, another portion of the semiconductor pattern can be the source or drain region of a transistor, and yet another portion of the semiconductor pattern can be a connecting electrode or a connecting signal line.

[0133] like Figure 4 As shown, the source region SC, active region AT, and drain region DE of transistor TR can be formed by semiconductor patterns.

[0134] A first insulating layer 10 is disposed on the buffer layer BFL. The first insulating layer 10 typically overlaps with multiple pixels and covers a semiconductor pattern. The first insulating layer 10 can be an inorganic layer and / or an organic layer, and can have a single-layer or multi-layer structure. The first insulating layer 10 can include one or more of, for example, alumina (Al2O3), titanium oxide (TiO2), silicon oxide (SiO2), silicon oxynitride (SiON), zirconium oxide (ZrO2), lanthanum oxide (La2O3), tantalum oxide (Ta2O5), yttrium oxide (Y2O3), and hafnium oxide (HfO2). In this example embodiment, the first insulating layer 10 can be a single-layer silicon oxide (SiO2) layer. Similarly, the first insulating layer 10 and the insulating layer of the circuit layer 110-2 can be inorganic layers and / or organic layers, and can have a single-layer or multi-layer structure. The inorganic layer can include one or more of the materials mentioned above.

[0135] The gate electrode GT of transistor TR is disposed on the first insulating layer 10. The gate electrode GT may comprise, for example, doped polysilicon (p-Si), a metal, or a combination thereof. For example, the gate electrode GT may be part of a metal pattern. The gate electrode GT overlaps with the active region AT and serves as a mask in the process of the doped semiconductor pattern.

[0136] The second insulating layer 20 may be disposed on the first insulating layer 10 and may cover the gate electrode GT. The second insulating layer 20 may be an inorganic layer and / or an organic layer, and may have a single-layer structure or a multi-layer structure. In this example embodiment, the second insulating layer 20 may be a single-layer silicon oxide (SiO2) layer.

[0137] The third insulating layer 30 is disposed on the second insulating layer 20. The electrode layer may be disposed between the second insulating layer 20 and the third insulating layer 30. The third insulating layer 30 may be a single layer of silicon oxide (SiO2).

[0138] The first connection electrode CNE1 can be disposed on the third insulating layer 30. The first connection electrode CNE1 can be coupled to the connection signal line SCL through the first contact hole CNT-1 that penetrates the first insulating layer 10, the second insulating layer 20 and the third insulating layer 30.

[0139] A fourth insulating layer 40 is disposed on the third insulating layer 30. The fourth insulating layer 40 may be a single layer of silicon oxide (SiO2). A fifth insulating layer 50 is disposed on the fourth insulating layer 40. The fifth insulating layer 50 may be an organic layer comprising an organic insulating material. The organic insulating material may include, for example, imide polymers, general polymers such as polymethyl methacrylate (PMMA) and polystyrene (PS), polymer derivatives having phenolic groups, acrylic polymers, aryl ether polymers, amide polymers, fluorinated polymers, p-xylene polymers, vinyl alcohol polymers, or mixtures thereof. The fifth insulating layer 50 may provide a planarized top surface. A second connecting electrode CNE2 may be disposed on the fifth insulating layer 50. The second connecting electrode CNE2 may be coupled to the first connecting electrode CNE1 through a second contact hole CNT-2 penetrating the fourth insulating layer 40 and the fifth insulating layer 50.

[0140] The sixth insulating layer 60 may be disposed on the fifth insulating layer 50 and may cover the second connecting electrode CNE2. The sixth insulating layer 60 may be an organic layer comprising an organic insulating material. The organic insulating material comprising the sixth insulating layer 60 may be the same as the organic insulating material of the fifth insulating layer 50, but this disclosure is not limited thereto.

[0141] A display element layer 110-3, including a light-emitting element EM, can be provided on the circuit layer 110-2. The light-emitting element EM may include a first electrode AE, a hole control layer HCL, an emission layer EML, an electron control layer ECL, and a second electrode CE.

[0142] The first electrode AE ​​can be disposed on the sixth insulating layer 60, and can be connected to the second connecting electrode CNE2 through the third contact hole CNT-3 penetrating the sixth insulating layer 60.

[0143] A pixel defining layer 70 may be disposed on the sixth insulating layer 60 and may cover a portion of the first electrode AE. In exemplary embodiments of this disclosure, the pixel defining layer 70 may, for example, comprise an organic material such as polyimide (PI) or a silicon-containing material such as hexamethyldisiloxane (HMDSO). An opening 70-OP is defined in the pixel defining layer 70. The opening 70-OP of the pixel defining layer 70 exposes at least a portion of the first electrode AE.

[0144] The display module 100 may have a pixel region PXA and a non-pixel region NPXA adjacent to the pixel region PXA. The non-pixel region NPXA may surround the pixel region PXA. In this example embodiment, the pixel region PXA is defined as a portion corresponding to a first electrode AE, which is exposed to the opening 70-OP.

[0145] The hole control layer HCL can be disposed on the first electrode AE. Alternatively, the hole control layer HCL can be disposed on both the pixel region PXA and the non-pixel region NPXA of the display module 100. The hole control layer HCL may include a hole transport layer and may also include a hole injection layer.

[0146] The emission layer EML can be disposed on the hole control layer HCL. Additionally, the emission layer EML can be disposed on the area corresponding to the opening 70-OP. For example, the emission layer EML can be formed on each pixel and can generate colored light for the corresponding pixel. However, this disclosure is not limited thereto, and the emission layer EML together with the hole control layer HCL can be disposed together on the pixel area PXA and the non-pixel area NPXA of the display module 100.

[0147] The electronic control layer (ECL) can be disposed on the emitter layer (EML) and may include an electron transport layer and an electron injection layer. An open mask can be used to allow the hole control layer (HCL) and the electronic control layer (ECL) to be formed together on multiple pixels. A second electrode (CE) is disposed on the electronic control layer (ECL). The second electrode (CE) can have a monolithic shape and can be disposed together on multiple pixels.

[0148] A capping layer 80 is disposed on and in contact with the second electrode CE, and may comprise an organic material. The capping layer 80 can protect the second electrode CE from subsequent processes such as sputtering and can improve the emission efficiency of the light-emitting element EM. The capping layer 80 may have a refractive index greater than that of the first inorganic layer 91, which will be discussed later.

[0149] An encapsulation layer 110-4 may be disposed on the display element layer 110-3. The encapsulation layer 110-4 may include a first inorganic layer 91, an organic layer 92, and a second inorganic layer 93, with the organic layer 92 interposed between the first inorganic layer 91 and the second inorganic layer 93. The organic layer 92 may be in direct contact with the first inorganic layer 91 and the second inorganic layer 93 and may have a substantially flat upper surface. The first inorganic layer 91 and the second inorganic layer 93 may protect the display element layer 110-3 from moisture and / or oxygen, and the organic layer 92 may protect the display element layer 110-3 from foreign matter such as dust particles. A portion of the second inorganic layer 93 located outside the active region 1000-A may be in direct contact with the first inorganic layer 91, which prevents the organic layer 92 from being exposed to the outside. The first inorganic layer 91 and the second inorganic layer 93 may each be, for example, a silicon nitride (Si3N4) layer, a silicon oxynitride (SiON) layer, and a silicon oxide (SiO2) layer. In exemplary embodiments of this disclosure, the first inorganic layer 91 and the second inorganic layer 93 may each comprise a titanium oxide (TiO2) layer or an aluminum oxide (Al2O3) layer. The organic layer 92 may comprise an acrylic organic layer, but this disclosure is not limited thereto.

[0150] In an exemplary embodiment of this disclosure, an inorganic layer, such as a lithium fluoride (LiF) layer, may be provided between the capping layer 80 and the first inorganic layer 91. The lithium fluoride (LiF) layer can improve the emission efficiency of the light-emitting element (EM).

[0151] The input sensor 120 may include a substrate insulating layer 120-1, a first conductive layer 120-2, a sensing insulating layer 120-3, a second conductive layer 120-4, and a covering insulating layer 120-5.

[0152] The substrate insulating layer 120-1 can be directly disposed on the display panel 110. For example, the substrate insulating layer 120-1 can be in direct contact with the second inorganic layer 93. The substrate insulating layer 120-1 can have a single-layer structure or a multi-layer structure. Alternatively, the substrate insulating layer 120-1 can be omitted. Alternatively, the substrate insulating layer 120-1 can be formed on a separate substrate layer, and an adhesive member can be used to couple the separate substrate layer to the display panel 110.

[0153] The first conductive layer 120-2 and the second conductive layer 120-4 may each have a monolayer structure or a multilayer structure with multiple layers stacked along the third direction DR3. The monolayer conductive layer may include a metal layer or a transparent conductive layer. The metal layer may include, for example, molybdenum (Mo), silver (Ag), titanium (Ti), copper (Cu), aluminum (Al), or alloys thereof. The transparent conductive layer may include, for example, a transparent conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium zinc tin oxide (IZTO). Alternatively or additionally, the transparent conductive layer may include metal nanowires, graphene, or a conductive polymer such as poly(3,4-ethylenedioxythiophene) (PEDOT).

[0154] A multilayer conductive layer may include multiple metal layers. These multiple metal layers can form, for example, a three-layer structure of titanium / aluminum / titanium (Ti / Al / Ti). A multilayer conductive layer may include at least one metal layer and at least one transparent conductive layer.

[0155] The first conductive layer 120-2 and the second conductive layer 120-4 may each include patterns constituting sensing electrodes and signal lines. The input sensor 120 can obtain information about external inputs by sensing changes in capacitance between the electrodes. Compared to sensing electrodes including a metal layer, sensing electrodes including a transparent conductive layer are not visible to the user and have an increased input area and therefore increased capacitance. In an exemplary embodiment of this disclosure, to prevent the user from seeing the sensing electrodes including the metal layer, the sensing electrodes including the metal layer may have a grid shape.

[0156] A sensing insulating layer 120-3 can be disposed between the first conductive layer 120-2 and the second conductive layer 120-4, and can cover the first conductive layer 120-2. A portion of the second conductive layer 120-4 can be electrically connected to a portion of the first conductive layer 120-2 through a contact hole penetrating the sensing insulating layer 120-3. A covering insulating layer 120-5 can be disposed on the sensing insulating layer 120-3 and can cover the second conductive layer 120-4.

[0157] One or both of the sensing insulating layer 120-3 and the covering insulating layer 120-5 may include an inorganic layer. The inorganic layer may include one or more of, for example, alumina (Al2O3), titanium oxide (TiO2), silicon oxide (SiO2), silicon oxynitride (SiON), zirconium oxide (ZrO2), and hafnium oxide (HfO2).

[0158] One or both of the sensing insulating layer 120-3 and the covering insulating layer 120-5 may include an organic layer. The organic layer may include one or more of, for example, acrylic resins, methacrylic resins, polyisoprene, vinyl resins, epoxy resins, urethane resins, cellulose resins, siloxane resins, polyimide resins, polyamide resins, and dinaphthalene-based resins.

[0159] Figure 5 A cross-sectional view of a display device according to an example embodiment of the present disclosure is shown.

[0160] Reference Figure 5 The display device 1000-1 may include a display module 100, a first adhesive layer 210, a second adhesive layer 220, a third adhesive layer 230-1, a fourth adhesive layer 240 and a fifth adhesive layer 250, as well as a first film 310, a second film 320, a third film 330, a fourth film 340 and a fifth film 350.

[0161] The first adhesive layer 210, the second adhesive layer 220, and the third adhesive layer 230-1 may each have a first thickness 210t, a second thickness 220t, and a third thickness 230t-1, respectively, and the third thickness 230t-1 of the third adhesive layer 230-1 disposed on the external location may be less than each of the first thickness 210t and the second thickness 220t. For example, each of the first thickness 210t and the second thickness 220t may be about 50 μm, and the third thickness 230t-1 may be about 25 μm. In the display device 1000-1, similar to the display device 1000, the third modulus of the third film 330 according to this example embodiment may be about 16.67% or less of the first modulus of the first film 310, such that the display device 1000-1 may have increased impact resistance and enhanced flexibility properties.

[0162] Figure 6 A cross-sectional view of a display device according to an example embodiment of the present disclosure is shown.

[0163] Reference Figure 6 The display device 1000-2 may include a display module 100, a first adhesive layer 210, a second adhesive layer 220, a third adhesive layer 230, a fourth adhesive layer 240 and a fifth adhesive layer 250, as well as a first film 310, a second film 320, a third film 330-1, a fourth film 340 and a fifth film 350.

[0164] The first film 310, the second film 320, and the third film 330-1 may each have the same first thickness 310t, second thickness 320t, and third thickness 330t-1. For example, each of the first thickness 310t, second thickness 320t, and third thickness 330t-1 may be about 40 μm. In the display device 1000-2, similar to the display device 1000, the third modulus of the third film 330-1 according to this example embodiment may be about 16.67% or less of the first modulus of the first film 310, such that the display device 1000-2 may have increased impact resistance and enhanced flexibility properties.

[0165] According to an example embodiment of this disclosure, at least three films can be disposed on the display module. Therefore, the display device can have increased impact resistance. Furthermore, the modulus of the films can gradually decrease with increasing distance from the display module. Therefore, the display device can enhance its folding properties.

[0166] It should be understood that the exemplary embodiments described herein are to be considered in a descriptive sense only and are not intended to be limiting. Although particular exemplary embodiments have been described with reference to several illustrative examples thereof, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of this disclosure as defined in the appended claims.

Claims

1. A display device, wherein, The display device includes: The display module has at least one folding area; A first film is disposed on the display module and has a first Young's modulus; A second film, disposed on the first film, further away from the display module than the first film, and having a second Young's modulus smaller than the first Young's modulus; and A third film, disposed on the second film, is further away from the display module than the second film, and has a third Young's modulus that is smaller than the second Young's modulus. The third Young's modulus is equal to or less than one-sixth of the first Young's modulus.

2. The display device according to claim 1, wherein, The third Young's modulus is equal to or greater than 1.5% of the first Young's modulus and equal to or less than 16.67% of the first Young's modulus.

3. The display device according to claim 1, wherein, The second Young's modulus is equal to or greater than 50% of the first Young's modulus and less than 100% of the first Young's modulus.

4. The display device according to claim 1, wherein, The first membrane is a composite material comprising one or more of polyimide, aromatic polyamide, glass fiber, chopped glass filaments and cellulose fiber.

5. The display device according to claim 1, wherein, The second membrane comprises polyethylene terephthalate, acrylic acid, polycarbonate, polyethylene naphthalate, or triacetyl cellulose.

6. The display device according to claim 1, wherein, The third membrane includes polyamide, polymethyl methacrylate, polyether block amide polymer, silicone polymer, or urethane polymer.

7. The display device according to claim 1, wherein, The thickness of the third membrane is greater than the thickness of the first membrane and the thickness of the second membrane. The thickness of the first membrane and the thickness of the second membrane are the same.

8. The display device according to claim 1, wherein, The display device further includes: A first adhesive layer is inserted between the display module and the first film; A second adhesive layer is inserted between the first membrane and the second membrane; and A third adhesive layer is inserted between the second membrane and the third membrane.

9. The display device according to claim 8, wherein, The thicknesses of the first adhesive layer, the second adhesive layer, and the third adhesive layer are the same as each other, or The thickness of the third adhesive layer is less than the thickness of the first adhesive layer and the thickness of the second adhesive layer.

10. The display device according to claim 8, wherein, At a predetermined temperature, the adhesive force of the second adhesive layer is less than that of the first adhesive layer and the third adhesive layer.

11. The display device according to claim 8, wherein, The display device further includes: A fourth adhesive layer is disposed beneath the display module; and The fourth film is disposed below the fourth adhesive layer and has a fourth Young's modulus that is less than the first Young's modulus.

12. The display device according to claim 11, wherein, The display device further includes: The fifth adhesive layer is disposed beneath the fourth film; and The fifth film is disposed below the fifth adhesive layer and has a fifth Young's modulus that is less than the first Young's modulus.

13. The display device according to claim 12, wherein, The fifth Young's modulus is less than the fourth Young's modulus, and The thickness of the fifth membrane is greater than the thickness of the fourth membrane.

14. The display device according to claim 1, wherein, Each of the first membrane and the second membrane comprises a membrane that satisfies the conditions of a yield strain of 1.9% to 2.5%, a plastic deformation index of 0.58 to 1, a recovery rate of 80% to 100%, and a strain rate of 0% to 30%.

15. The display device according to claim 1, wherein, The third membrane includes a membrane that satisfies the following conditions: yield strain of 1.9% to 2.5%, plastic deformation index of 0.58 to 1, recovery ratio of 80% to 100%, and strain ratio of 0% to 100%.

16. A display device, wherein, The display device includes: The display module has at least one folding area; A first film is disposed on the display module and has a first Young's modulus; The second film is disposed on the first film, further away from the display module than the first film, and has a second Young's modulus that is smaller than the first Young's modulus; A third film is disposed on the second film, further away from the display module than the second film, and has a third Young's modulus that is smaller than the first Young's modulus and the second Young's modulus; A first adhesive layer is inserted between the display module and the first film; A second adhesive layer is inserted between the first membrane and the second membrane; and A third adhesive layer is inserted between the second membrane and the third membrane. Wherein, at a predetermined temperature, one or both of the adhesive forces of the second adhesive layer and the third adhesive layer are less than the adhesive force of the first adhesive layer.

17. The display device according to claim 16, wherein, The third Young's modulus is equal to or greater than 1.5% of the first Young's modulus and equal to or less than 16.67% of the first Young's modulus.

18. The display device according to claim 16, wherein, The display device further includes: A fourth film, disposed below the display module and having a fourth Young's modulus less than the first Young's modulus; and The fifth membrane is disposed below the fourth membrane and has a fifth Young's modulus that is smaller than the fourth Young's modulus. The thickness of the fifth membrane is greater than the thickness of the fourth membrane.

19. The display device according to claim 16, wherein, The thickness of the first film and the thickness of the second film are the same, and The thickness of the third membrane is greater than the thickness of the first membrane and the thickness of the second membrane.

20. The display device according to claim 16, wherein, The first membrane is a composite material comprising one or more of polyimide, aromatic polyamide, glass fiber, chopped glass filaments, and cellulose fiber. The second membrane comprises polyethylene terephthalate, acrylic acid, polycarbonate, polyethylene naphthalate, or triacetyl cellulose, and The third membrane includes polyamide, polymethyl methacrylate, polyether block amide polymer, silicone polymer, or urethane polymer.

21. The display device according to claim 16, wherein, Each of the first and second membranes comprises a membrane satisfying the conditions of a yield strain of 1.9% to 2.5%, a plastic deformation index of 0.58 to 1, a recovery rate of 80% to 100%, and a strain ratio of 0% to 30%. The third membrane includes a membrane that satisfies the following conditions: yield strain of 1.9% to 2.5%, plastic deformation index of 0.58 to 1, recovery ratio of 80% to 100%, and strain ratio of 0% to 100%.

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