Display device

Abstract

A display device is provided. The display device includes a display panel, a covering member arranged on the display panel, and an adhesive layer arranged between the display panel and the covering member. The adhesive layer has a first surface facing the covering member and a second surface facing the display panel, and in a first direction from the first surface toward the second surface, the adhesive layer includes a first region and a second region arranged at different positions from each other. The modulus of the first region is different from the modulus of the second region.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2019-0051435, filed on May 2, 2019, which is hereby incorporated by reference for all purposes as if fully set forth herein. Technical Field

[0003] Exemplary implementations of the present invention generally relate to a layer for a display device, and more particularly, to an adhesive film for a display device, a display device including the adhesive film, and a method of manufacturing the adhesive film for a display device. Background Art

[0004] In recent years, liquid crystal display (LCD) devices or organic light emitting diode (OLED) display devices may be used as display devices of electronic devices such as mobile phones, navigation devices, digital cameras, electronic books, portable game machines, and various terminals.

[0005] In conventional display devices used in such electronic devices, a transparent cover window may be provided in front of a display panel so that a user can observe a display area of ​​the display panel. The cover window should be strong and durable to resist external impacts to protect the display panel in the device.

[0006] In addition, recently, foldable or rollable display devices have been actively studied, and a cover window applied to such a display device includes a transparent window that is flexible so as to be folded.

[0007] In this case, an adhesive layer for attaching the cover window to the display panel may be disposed between the display panel and the cover window.

[0008] The above information disclosed in this Background section is only for understanding the background of the present invention concept and therefore it may contain information that does not constitute the prior art. Summary of the invention

[0009] The applicant has found that it is preferred to use an adhesive layer having a relatively high modulus and a relatively high bending stiffness to prevent the cover window from being damaged when the display device is folded or rolled. On the other hand, an adhesive layer having a relatively low modulus and a relatively low bending stiffness may be preferred to prevent bright spots from occurring due to impacts applied to the display panel.

[0010] The adhesive film constructed according to the principles and exemplary implementations of the present invention and the display device including the adhesive film and the manufacturing method of the adhesive film according to the principles and exemplary implementations of the present invention can prevent or at least reduce the damage and / or destruction of the covering member when the display device is folded, and prevent or at least reduce visually identifiable spots (such as bright spots) due to the impact applied to the display device and / or its display panel. For example, the adhesive layer for the display device has a modulus and bending stiffness that varies in thickness and / or length direction.

[0011] The adhesive layer for the display device may include a first region having a relatively high modulus and a relatively high bending stiffness and a second region having a relatively low modulus and a relatively low bending stiffness. For example, the first region may include a first surface of the adhesive layer, and the second region may include a second surface of the adhesive layer opposite to the first surface. The first region of the adhesive layer may prevent or at least reduce the covering member from being damaged and / or destroyed when the display device is folded, and the second region of the adhesive layer may prevent or at least reduce the bright spots that occur due to the impact applied to the display device. The first surface may be the front surface of the adhesive layer, and the second surface may be the rear surface of the adhesive layer. For another example, the first region may overlap with the folding region of the display device, and the second region may overlap with the non-folding region of the display device. In this case, the first region may prevent or at least reduce the buckling caused by the shear force of the adhesive layer that may be generated when the folding region is folded, and the second region may prevent or at least reduce the bright spots that occur due to the impact applied to the display device.

[0012] The adhesive layer for the display device may include a single layer. In this way, the manufacturing process can be simplified and the image quality of the display device can be improved because the single adhesive layer can prevent or at least reduce the reflection or refraction of light that may occur at the interface between multiple layers. In addition, unlike multiple layers, since a single adhesive layer is not easily peeled off, the adhesive layer and the display device can be strong against stress.

[0013] Additional features of the inventive concept will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the inventive concept.

[0014] According to one aspect of the present invention, a display device includes a display panel, a covering member arranged on the display panel, and an adhesive layer arranged between the display panel and the covering member, wherein the adhesive layer has a first surface facing the covering member and a second surface facing the display panel, and includes a first region and a second region arranged at different positions from each other in a first direction from the first surface toward the second surface, and wherein a modulus of the first region is different from a modulus of the second region.

[0015] The adhesive layer may form a single layer including the first region and the second region without having an interface between the first surface and the second surface.

[0016] The adhesive layer may have a modulus that is continuous between the first surface and the second surface.

[0017] The modulus of the first region may be greater than or equal to about 100 KPa and less than or equal to about 1000 KPa, and the modulus of the second region may be about 100 KPa or less.

[0018] The difference between the modulus of the first region and the modulus of the second region may be about 100 KPa or greater.

[0019] The first region may include a first surface, the second region may include a second surface, and a modulus of the first region may be higher than a modulus of the second region.

[0020] The first region may include a first surface, the second region may include a second surface, and a modulus of the first region may be lower than a modulus of the second region.

[0021] The bending stiffness of the first region may be greater than or equal to about 30 N·cm and less than or equal to about 50 N·cm, and the bending stiffness of the second region may be greater than or equal to about 15 N·cm and less than or equal to about 30 N·cm.

[0022] Each of the moduli of the first region and the second region may gradually change along the first direction, respectively, the first region may include a first surface, and the second region may include a second surface.

[0023] The adhesive layer may further include a third region having a modulus gradually changing along the first direction.

[0024] The third region may have a modulus that gradually decreases along the first direction.

[0025] The first region may include a first surface, the second region may include a second surface, the third region may be disposed between the first region and the second region, and a modulus of the first region and a modulus of the second region may be constant in a first direction.

[0026] The third region may have a modulus that gradually increases along the first direction.

[0027] The first region may include a third region having a modulus gradually decreasing along the first direction, and the second region may include a fourth region having a modulus gradually increasing along the first direction.

[0028] The first region may include a first surface, and the second region may include a second surface.

[0029] The first region may include the second surface, and the second region may include the first surface.

[0030] The adhesive layer may further include a third region disposed between the first region and the second region, and each of a modulus of the first region and a modulus of the second region may be higher than a modulus of the third region.

[0031] The adhesive layer may further include a third region disposed between the first region and the second region, and each of a modulus of the first region and a modulus of the second region may be lower than a modulus of the third region.

[0032] The display device may be foldable or rollable.

[0033] According to another aspect of the present invention, a display device includes a display panel, a covering member arranged on the display panel, and a single adhesive layer, wherein the single adhesive layer includes a first surface facing the covering member and a second surface facing the display panel, and there is no interface between the first surface and the second surface, and the single adhesive layer is arranged between the display panel and the covering member, wherein the modulus of the first surface is higher than the modulus of the second surface.

[0034] The difference between the modulus of the first surface and the modulus of the second surface may be about 100 KPa or greater.

[0035] According to another aspect of the present invention, a display device includes a display panel, a covering member arranged on the display panel, and an adhesive layer arranged between the display panel and the covering member, wherein the adhesive layer includes a non-folding area and a folding area arranged between the non-folding areas, and wherein the modulus of the folding area is greater than the modulus of the non-folding area.

[0036] The modulus of the folded region may be greater than or equal to about 100 KPa and less than or equal to about 1000 KPa, and the modulus of the unfolded region may be about 100 KPa or less.

[0037] The difference between the modulus of the folded region and the modulus of the unfolded region may be about 100 KPa or more.

[0038] According to another aspect of the present invention, an adhesive film for a display device is provided, the adhesive film having a first surface and a second surface opposite to the first surface, including a first region and a second region arranged at different positions from each other in a thickness direction from the first surface toward the second surface, wherein the modulus of the first region is different from the modulus of the second region.

[0039] The adhesive film may form a single layer including the first region and the second region without having an interface between the first surface and the second surface.

[0040] A maximum value of the modulus of the adhesive film may be about 100 KPa or more and about 1000 KPa or less, and a minimum value of the modulus of the adhesive film may be about 100 KPa or less.

[0041] The adhesive film may have a deviation in modulus in a thickness direction of about 100 KPa or more.

[0042] The maximum value of the bending rigidity of the adhesive film may be about 30 N·cm or more and about 50 N·cm or less, and the minimum value of the bending rigidity of the adhesive film may be about 15 N·cm or more and about 30 N·cm or less.

[0043] The modulus of the adhesive film may gradually increase along the thickness direction.

[0044] The first region may include a third region having a modulus gradually decreasing along the thickness direction, and the second region may include a fourth region having a modulus gradually increasing along the thickness direction.

[0045] The adhesive film may further include a third region disposed between the first region and the second region, wherein each of a modulus of the first region and a modulus of the second region may be higher than a modulus of the third region.

[0046] The adhesive film may further include a third region disposed between the first region and the second region, wherein each of a modulus of the first region and a modulus of the second region may be lower than a modulus of the third region.

[0047] According to still another aspect of the present invention, an adhesive film for a display device includes a first surface and a second surface opposite to the first surface without an interface between the first surface and the second surface, wherein a modulus of the first surface is higher than a modulus of the second surface.

[0048] According to one aspect of the present invention, a method for manufacturing an adhesive film for a display device is provided, the method comprising: forming a first component comprising a resin and a first initiator for initiating a polymerization reaction of the resin on a first release film; forming a second component comprising a resin and a second initiator for initiating a polymerization reaction of the resin on the applied first component; irradiating the applied first component and the second component with light having a first wavelength range; and irradiating the applied first component and the second component with light having a second wavelength range, wherein the first initiator initiates the polymerization reaction of the resin with the light having the first wavelength range without activating the initiation of the polymerization reaction with light having the second wavelength range, and wherein the second initiator initiates the polymerization reaction of the resin with the light having the second wavelength range without activating the initiation of the polymerization reaction with light having the first wavelength range.

[0049] The method may further include forming a third composition including a resin and a third initiator on the second composition, wherein the third initiator initiates polymerization of the resin with light having a third wavelength range, but does not activate initiation of polymerization with light having a second wavelength range.

[0050] The third initiator may initiate polymerization of the resin with light having a third wavelength range, without activating initiation of the polymerization with light having a first wavelength range.

[0051] The irradiation time of the light having the first wavelength range may be different from the irradiation time of the light having the second wavelength range.

[0052] The intensity of light having the first wavelength range may be different from the intensity of light having the second wavelength range.

[0053] The concentration of the first initiator relative to the first composition is different from the concentration of the second initiator relative to the second composition.

[0054] Forming the second component on the first component may include: applying the second component on a second release film; and laminating the first release film and the second release film to each other in a state in which the applied first component and the second component face each other.

[0055] Forming the first component on the first release film may include: applying a first initiator on the first release film; and applying a resin on the applied first initiator. Applying the second component on the second release film may include: applying a second initiator on the second release film; and applying a resin on the applied second initiator.

[0056] According to another aspect of the present invention, a method of manufacturing an adhesive film for a display device includes: applying an initiator to a release film; applying a resin on the applied initiator; and irradiating the applied initiator and the resin with light.

[0057] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the inventive concept.

[0059] Figure 1 is a perspective view of a display device constructed according to the concept of the present invention.

[0060] Figure 2 It is shown Figure 1 A cross-sectional view of a state where the display device is folded.

[0061] Figure 3 It is shown Figure 1 A cross-sectional view of a state where the display device is rolled up.

[0062] Figure 4are plan views of some embodiments of pixels of a display device.

[0063] Figure 5 is along Figure 4 A cross-sectional view taken along line II'.

[0064] Figure 6 is a perspective view of an embodiment of multiple adhesive layers.

[0065] Figure 7 is a graph showing the modulus of various embodiments of the adhesive layer.

[0066] Figure 8 is a perspective view of an embodiment of an adhesive layer.

[0067] Figures 9 to 12 is a graph showing the modulus of an embodiment of an adhesive layer.

[0068] Fig.13 is a graph showing the modulus of another embodiment of multiple bonding layers.

[0069] Figures 14 to 16 : is a graph showing the modulus of other embodiments of the adhesive layer.

[0070] Fig.17 is a perspective view of another embodiment of an adhesive layer.

[0071] Figures 18 to 20 is a graph showing the modulus of yet further embodiments of adhesive layers.

[0072] Figures 21 to 28 are graphs each showing the concentration of an initiator before curing an adhesive layer according to an embodiment.

[0073] FIG. 29A to FIG. 29G It is a cross-sectional view showing an embodiment of a method for producing an adhesive layer.

[0074] FIG. 30A to FIG. 30C It is a cross-sectional view showing another embodiment of the method for producing an adhesive layer.

[0075] FIG. 31A to FIG. 31F This is a cross-sectional view showing still another embodiment of the method for producing the adhesive layer.

[0076] FIG. 32A to FIG. 32D It is a cross-sectional view showing still another embodiment of the method for producing the adhesive layer.

[0077] FIG. 33A to FIG. 33E It is a cross-sectional view showing still another embodiment of the method for producing an adhesive layer.

[0078] Fig.34 and Fig.35are graphs each showing the concentration of an initiator before curing an adhesive layer according to an embodiment.

[0079] FIG. 36A to FIG. 36E It is a cross-sectional view showing still another embodiment of the method for producing the adhesive layer. DETAILED DESCRIPTION

[0080] In the following description, for the purpose of explanation, many specific details are set forth to provide a thorough understanding of various embodiments or implementations of the present invention. As used herein, "embodiment" and "implementation" are interchangeable words, which are non-limiting examples of devices or methods using one or more of the inventive concepts disclosed herein. However, it is apparent that various embodiments can be practiced without these specific details or with one or more equivalent arrangements. In other examples, known structures and devices are shown in block diagram form to avoid unnecessary confusion of various embodiments. In addition, various embodiments may be different, but need not be exclusive. For example, without departing from the inventive concept, the specific shape, configuration and characteristics of the embodiment may be used or implemented in another embodiment.

[0081] Unless otherwise specified, the embodiments shown should be understood as providing exemplary features of different details of some ways in which the inventive concept can be implemented in practice. Therefore, unless otherwise specified, the features, components, modules, layers, films, panels, regions and / or aspects, etc. (hereinafter individually or collectively referred to as "elements") of various embodiments may be combined, separated, interchanged and / or rearranged in other ways without departing from the inventive concept.

[0082] The use of cross hatching and / or shading in the drawings is generally provided to clarify the boundaries between adjacent elements. Thus, unless otherwise stated, the presence or absence of cross hatching or shading will not convey or indicate any preference or requirement for a particular material, material properties, size, ratio, commonality between the elements shown and / or any other characteristics, attributes, performances, etc. of the elements. In addition, in the drawings, the size and relative size of the elements may be exaggerated for the purpose of clarity and / or description. When the embodiment can be implemented in different ways, the specific process sequence may be performed differently from the described sequence. For example, two processes described in succession may be performed substantially simultaneously or in an order opposite to the described order. In addition, similar reference numerals represent similar elements.

[0083] When an element (e.g., layer) is referred to as being "on", "connected to" or "coupled to" another element or layer, the element (e.g., layer) may be directly on, connected to or coupled to another element or layer, or there may be an intermediate element or layer. However, when an element or layer is referred to as being "directly" "on", "directly connected to" or "directly coupled to" another element or layer, there are no intermediate elements or layers. For this reason, the term "connected" may indicate a physical, electrical and / or fluid connection with or without an intermediate element. In addition, the D1-axis, D2-axis and D3-axis are not limited to the three axes of a rectangular coordinate system (such as an x-axis, a y-axis and a z-axis), and may be interpreted as a broader meaning. For example, the D1-axis, the D2-axis and the D3-axis may be perpendicular to each other, or may represent different directions that are not perpendicular to each other. For the purpose of this disclosure, "at least one of X, Y, and Z" and "at least one selected from the group consisting of X, Y, and Z" may be interpreted as any combination of only X, only Y, only Z, or two or more of X, Y, and Z, such as XYZ, XYY, YZ, and ZZ. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0084] Although the terms "first", "second", etc. may be used herein to describe various types of elements, these components should not be limited by these terms. These terms are used to distinguish one element from another element. Therefore, without departing from the teachings of the present disclosure, the first element discussed below may be referred to as the second element.

[0085] Spatially relative terms such as "beneath," "below," "lower," "above," "upper," "over," "higher," "side" (e.g., as in "sidewall"), etc. may be used herein for descriptive purposes, and thus, to describe the relationship of one element to another element as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use, operation, and / or manufacture in addition to the orientations depicted in the figures. For example, if the device in the figures is turned over, elements described as being "below" or "beneath" other elements or features would subsequently be oriented to be "above" the other elements or features. Thus, the exemplary term "below" may include both orientations of above and below. Furthermore, the device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations), and thus, the spatially relative descriptors used herein are interpreted accordingly.

[0086] The terms used herein are for the purpose of describing specific embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" as used herein are also intended to include the plural forms. In addition, when the words "comprise", "comprising", "include" and / or "including" are used in this specification, the existence of the stated features, integers, steps, operations, elements, parts and / or clusters thereof is indicated, but the existence or addition of one or more other features, integers, steps, operations, elements, parts and / or clusters thereof is not excluded. It is also noted that, as used herein, the words "substantially", "about" and similar words are used as approximate words rather than words of degree, and thus, are used to take into account the inherent deviations of measured values, calculated values ​​and / or provided values ​​that will be recognized by those of ordinary skill in the art.

[0087] Various embodiments are described herein with reference to cross-sectional and / or exploded views that are schematic illustrations of idealized embodiments and / or intermediate structures. Thus, variations in the shapes of the illustrations as a result of, for example, manufacturing techniques and / or tolerances are to be expected. Thus, the embodiments disclosed herein should not necessarily be construed as limited to the specific illustrated shapes of the regions, but rather include deviations in shape resulting from, for example, manufacturing. In this manner, the regions illustrated in the figures may be schematic in nature, and the shapes of these regions may not reflect the actual shapes of the regions of the device, and thus are not necessarily intended to be limiting.

[0088] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure belongs. Unless explicitly defined as such herein, terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and should not be interpreted in an idealized or overly formal sense.

[0089] Figure 1 is a perspective view of a display device DD constructed according to the concept of the present invention. Figure 2 It is shown Figure 1 A cross-sectional view of a state where the display device DD is folded. Figure 3 It is shown Figure 1 A cross-sectional view of a state where the display device DD is rolled up.

[0090] Reference Figure 1, the display device DD includes a display panel DP displaying an image, a cover member CM disposed on a side where the image is displayed, and an adhesive layer PSA for attaching the display panel DP and the cover member CM.

[0091] In an embodiment, the display device DD may include any one of a liquid crystal display (LCD) panel, a light emitting diode (LED) display panel, an organic light emitting diode (OLED) display panel, a microelectromechanical system (MEMS) display panel, and an electronic paper display panel.

[0092] like Figure 1 As shown in , the display device DD (ie, the display panel DP and the cover member CM) may be provided in a flat state, but it may be provided in a different shape deforming at least a portion of the display panel DP and the cover member CM.

[0093] Combination Figure 1 Reference Figure 2 and Figure 3 At least a portion of the display device DD may be flexible, or the entire display device DD may be flexible. Since the display device DD is flexible, the display device DD may be configured as follows in the flexible region. Figure 2 folded as shown in Figure 3 is curled as shown.

[0094] Reference Figure 1 , the folding line FL along which the display device DD is folded may pass through the center of the display device DD and may be parallel to the third direction D3. However, the position of the folding line FL is not limited thereto, and may be set in a direction parallel to the second direction D2 or in a direction inclined to the second direction D2 or the third direction D3. In addition, it is obvious that it is not necessary for the folding line FL to pass through the center of the display device DD.

[0095] In addition, the display device DD may be provided in an inner folding scheme in which the image display surface is folded inwardly along the folding lines FL so as not to be observed, or in an outer folding scheme in which the image display surface is folded outwardly along the folding lines FL so as to be observed. In addition, when the display device DD is folded along a plurality of folding lines FL, a portion of the image display surface may be folded inwardly, and another portion of the image display surface may be folded outwardly.

[0096] The first direction D1 indicates a direction perpendicular to the second direction D2 and the third direction D3. The first direction D1 corresponds to the thickness direction of the display device DD, the display panel DP, the cover member CM, and the adhesive layer PSA. In the following description, the first direction D1 is defined as a direction from the cover member CM toward the display panel DP. The length of the display device DD in the second direction D2 may be greater than the length of the display device DD in the third direction D3. The first direction D1, the second direction D2, and the third direction D3 may indicate the thickness direction, the width direction, and the length direction of the display device DD, the display panel DP, the adhesive layer PSA, or the cover member CM, respectively.

[0097] Reference Figure 3 , the display device DD may be rollable so that one surface faces and / or contacts another surface. The direction in which the display device DD is rolled may be the second direction D2 or the third direction D3. However, the embodiment is not limited thereto. For example, the display device DD may be rolled in a direction inclined to the second direction D2 or the third direction D3. In addition, in the display device DD, the rolled area may be a part of the display device DD, or the entire area of ​​the display device DD may be rolled.

[0098] For convenience of description, although flexibility has been described with reference to the display device DD, it may be applied to the display panel DP, the cover member CM, the adhesive layer PSA, and / or layers thereof.

[0099] Figure 4 are plan views of embodiments of some of the pixels of the display device DD. Figure 5 is along Figure 4 A cross-sectional view taken along line II'.

[0100] Reference Figure 4 and Figure 5 , the OLED display device DD includes a substrate 100, a wiring unit 200, an OLED 300, and a thin film encapsulation layer 350. The OLED display device DD may further include a buffer layer 120 and a pixel defining layer 190.

[0101] The substrate 100 may include an insulating material selected from the group consisting of glass, quartz, ceramic, and plastic. However, the embodiment is not limited thereto, and the substrate 100 may include a metal material such as stainless steel.

[0102] The buffer layer 120 is arranged on the substrate 100. The buffer layer 120 may include one or more layers selected from various inorganic layers and organic layers. The buffer layer 120 is used to prevent unnecessary substances (e.g., impurities or moisture) from penetrating into the wiring unit 200 or the OLED 300 and to flatten the surface below it. However, the buffer layer 120 is not necessary and may be omitted according to the type of the substrate 100 and process conditions.

[0103] The wiring unit 200 is disposed on the buffer layer 120. The wiring unit 200 includes a plurality of thin film transistors (TFTs) 10 and 20, and drives the OLED 300. That is, the OLED 300 emits light according to a driving signal received from the wiring unit 200 to display an image.

[0104] Figure 4 and Figure 5 An active matrix organic light emitting diode (AMOLED) display device having a 2Tr-1Cap structure is shown, and in each pixel, the 2Tr-1Cap structure includes two TFTs 10 and 20 and one capacitor 80. However, the embodiment is not limited thereto, and the OLED display device DD may include three or more transistors and two or more capacitors in each pixel, and may have various structures including additional wiring. Herein, a pixel indicates a minimum unit for displaying an image, and the OLED display device DD displays an image through a plurality of pixels.

[0105] Each pixel includes a switching TFT 10, a driving TFT 20, a capacitor 80, and an OLED 300. The configuration of the switching TFT 10, the driving TFT 20, and the capacitor 80 is collectively referred to as a wiring unit 200. In addition, a gate line 151 extending in one direction and a data line 171 and a common power line 172 insulated from and intersecting the gate line 151 are arranged at the wiring unit 200. Each pixel may be defined by the gate line 151, the data line 171, and the common power line 172 used as a boundary, but the embodiment is not limited thereto. The pixel may be defined by a pixel defining layer 190.

[0106] The OLED 300 includes a first electrode 310, an organic light emitting layer 320 located on the first electrode 310, and a second electrode 330 located on the organic light emitting layer 320. Holes and electrons are applied to the organic light emitting layer 320 from the first electrode 310 and the second electrode 330, respectively, and then combined with each other therein to form excitons. When the excitons transition from an excited state to a ground state, light is emitted.

[0107] The capacitor 80 includes a pair of capacitor plates 158 and 178 with an insulating interlayer 160 interposed therebetween. In this embodiment, the insulating interlayer 160 may be a dielectric element. The capacitance of the capacitor 80 is determined by the charge accumulated in the capacitor 80 and the voltage across the pair of capacitor plates 158 and 178.

[0108] The switching TFT 10 includes a switching semiconductor layer 131, a switching gate electrode 152, a switching source electrode 173, and a switching drain electrode 174. The driving TFT 20 includes a driving semiconductor layer 132, a driving gate electrode 155, a driving source electrode 176, and a driving drain electrode 177. The gate insulating layer 130 is provided to insulate the switching semiconductor layer 131 and the driving semiconductor layer 132 from the switching gate electrode 152 and the driving gate electrode 155.

[0109] The switching TFT 10 may be used as a switching element for selecting a pixel to perform light emission. The switching gate electrode 152 is connected to the gate line 151, and the switching source electrode 173 is connected to the data line 171. The switching drain electrode 174 is spaced apart from the switching source electrode 173 and connected to one of the capacitor plates (e.g., the capacitor plate 158).

[0110] The driving TFT 20 applies driving power that allows the organic light emitting layer 320 of the OLED 300 in the selected pixel to emit light to the first electrode 310 as the pixel electrode. The driving gate electrode 155 is connected to the capacitor plate 158 connected to the switching drain electrode 174. Each of the other of the capacitor plates (e.g., the capacitor plate 178) and the driving source electrode 176 is connected to the common power line 172. The driving drain electrode 177 is connected to the first electrode 310 of the OLED 300 through the contact hole.

[0111] Through the above structure, the switching TFT 10 is operated based on the gate voltage applied to the gate line 151, and serves to transmit the data voltage applied to the data line 171 to the driving TFT 20. A voltage equal to the difference between the common voltage applied from the common power line 172 to the driving TFT 20 and the data voltage transmitted by (or from) the switching TFT 10 is stored in the capacitor 80, and a current corresponding to the voltage stored in the capacitor 80 flows to the OLED 300 through the driving TFT 20 so that the OLED 300 can emit light.

[0112] The OLED 300 emits light according to the driving signal received from the wiring unit 200. In addition, the OLED 300 may include a first electrode 310, a second electrode 330, and an organic light emitting layer 320 arranged between the first electrode 310 and the second electrode 330, the first electrode 310 serving as an anode for injecting holes, and the second electrode 330 serving as a cathode for injecting electrons. That is, the first electrode 310, the organic light emitting layer 320, and the second electrode 330 are sequentially stacked to form the OLED 300. However, the embodiment is not limited thereto. For example, the first electrode 310 may serve as a cathode, and the second electrode 330 may serve as an anode.

[0113] In an embodiment, the first electrode 310 may include a reflective film, and the second electrode 330 may include a transflective film. Accordingly, light generated in the organic light emitting layer 320 may pass through the second electrode 330 to be emitted outward. That is, the OLED display device DD may have a top emission type structure.

[0114] In an embodiment, the transflective film and the reflective film may include one or more metals, for example, magnesium (Mg), silver (Ag), gold (Au), calcium (Ca), lithium (Li), chromium (Cr) and aluminum (Al) or alloys thereof. In such an embodiment, whether the film is transflective or reflective depends on the thickness of the film. Typically, the transflective film has a thickness of about 200 nm or less. As the thickness of the transflective film decreases, the transmittance increases, and as the thickness of the transflective film increases, the transmittance decreases.

[0115] In addition, the first electrode 310 may include a transparent conductive film. That is, the first electrode 310 may have a multilayer structure including a reflective film and a transparent conductive film. The transparent conductive film of the first electrode 310 is arranged between the reflective film and the organic light emitting layer 320. In addition, the first electrode 310 may have a three-layer structure in which a transparent conductive film, a reflective film, and a transparent conductive film are sequentially stacked. The first electrode 310 may include only a transparent conductive film. In this case, the first electrode 310 becomes a transparent electrode.

[0116] The transparent conductive film may include a transparent conductive oxide (TCO), such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium oxide (In2O3). The transparent conductive film has a relatively high work function. Accordingly, when the first electrode 310 includes the transparent conductive film, hole injection through the first electrode 310 is facilitated.

[0117] The second electrode 330 may include a transparent conductive film. When the second electrode 330 includes a transparent conductive film, the second electrode 330 may be an anode for injecting holes. In such an embodiment, the first electrode 310 may include only a reflective film to function as a cathode.

[0118] At least one of a hole injection layer HIL and a hole transport layer HTL may be arranged between the first electrode 310 serving as an anode and the organic light-emitting layer 320, and at least one of an electron transport layer ETL and an electron injection layer EIL may be arranged between the organic light-emitting layer 320 and the second electrode 330 serving as a cathode.

[0119] In an implementation, an additional layer may be further disposed between the organic light emitting layer 320 and the first electrode 310 and between the organic light emitting layer 320 and the second electrode 330 .

[0120] The pixel defining layer 190 has an opening 195. The opening 195 of the pixel defining layer 190 exposes a portion of the first electrode 310. The first electrode 310, the organic light emitting layer 320, and the second electrode 330 are sequentially stacked in the opening 195 of the pixel defining layer 190. In this embodiment, the second electrode 330 may also be arranged on the pixel defining layer 190 and on the organic light emitting layer 320. In addition, the HIL, HTL, ETL, and EIL may also be arranged between the pixel defining layer 190 and the second electrode 330. The OLED 300 emits light from the organic light emitting layer 320 in the opening 195 of the pixel defining layer 190. Thus, the opening 195 of the pixel defining layer 190 defines a light emitting area.

[0121] The thin film encapsulation layer 350 is disposed on the second electrode 330. The thin film encapsulation layer 350 seals the first electrode 310, the organic light emitting layer 320, and the second electrode 330, and protects them from the external environment.

[0122] The thin film encapsulation layer 350 may have a structure in which at least one organic layer 370 and at least one inorganic layer 360 and 380 are alternately arranged. However, the embodiment is not limited thereto, and the thin film encapsulation layer 350 may include a single layer of an organic layer or an inorganic layer.

[0123] The OLED display device DD may include, for example, a touch sensing layer, a polarizing layer, and a color filter layer disposed on the thin film encapsulation layer 350 .

[0124] The cover member CM is disposed on the front surface of the display panel DP displaying an image. An adhesive layer PSA is interposed between the cover member CM and the front surface of the display panel DP. The cover member CM may transmit light generated by the display panel DP.

[0125] For example, the cover member CM may include a window including a flexible material such as tempered glass, tempered plastic or polymer material. The window may be a flexible glass in a film form. The glass window in a film form may have a thickness of about 100 μm or less, and more preferably has a thickness of about 75 μm or less.

[0126] The cover member CM may also include a protective film attached to the front surface or rear surface of the window. In addition, the cover member CM may include a touch sensing layer, a polarizing layer, a color filter layer, etc. arranged at the front surface or rear surface of the window. In addition, the cover member CM may include a light shielding layer and a hard coating layer formed at the front surface or rear surface of the window.

[0127] The adhesive layer PSA is disposed between the cover member CM and the display panel DP to attach them to each other. The adhesive layer PSA may be in direct contact with the front surface of the display panel DP and the rear surface of the cover member CM. The adhesive layer PSA may include a pressure-sensitive adhesive or an optically transparent adhesive.

[0128] Figure 6 is a perspective view of an embodiment of multiple adhesive layers. Figure 7 is a graph showing the modulus of various embodiments of the adhesive layer.

[0129] Reference Figure 6 , Figure 1 At least two adhesive layers PSA1 and PSA2 may be provided between the cover member CM and the display panel DP. The first adhesive layer PSA1 has a front surface S11 facing the cover member CM and a rear surface S12 facing the display panel DP. The second adhesive layer PSA2 has a front surface S21 facing the cover member CM and a rear surface S22 facing the display panel DP. The front surface S11 of the first adhesive layer PSA1 may be in direct contact with the cover member CM or a window of the cover member CM. The rear surface S22 of the second adhesive layer PSA2 may be in direct contact with the display panel DP or the thin film encapsulation layer 350 of the display panel DP. The rear surface S12 of the first adhesive layer PSA1 and the front surface S21 of the second adhesive layer PSA2 are in contact with each other.

[0130] Reference Figure 7 , the modulus of the first adhesive layer PSA1 is higher than the modulus of the second adhesive layer PSA2. In the first direction D1 as the thickness direction, each of the first adhesive layer PSA1 and the second adhesive layer PSA2 may have a substantially constant modulus. The modulus of the first adhesive layer PSA1 or the front surface S11 of the first adhesive layer PSA1 may be greater than or equal to about 100 KPa and less than or equal to about 1000 KPa, and the modulus of the second adhesive layer PSA2 or the rear surface S22 of the second adhesive layer PSA2 may be about 100 KPa or less. The difference between the modulus of the first adhesive layer PSA1 or the front surface S11 of the first adhesive layer PSA1 and the modulus of the second adhesive layer PSA2 or the rear surface S22 of the second adhesive layer PSA2 may be about 100 KPa or more.

[0131] The first adhesive layer PSA1 has a bending rigidity higher than that of the second adhesive layer PSA2. In the first direction D1 as the thickness direction, each of the first adhesive layer PSA1 and the second adhesive layer PSA2 may have a substantially constant bending rigidity. The bending rigidity of the first adhesive layer PSA1 or the front surface S11 of the first adhesive layer PSA1 may be greater than or equal to about 30N·cm and less than or equal to about 50N·cm, and the bending rigidity of the second adhesive layer PSA2 or the rear surface S22 of the second adhesive layer PSA2 may be greater than or equal to about 15N·cm and less than or equal to about 30N·cm. The difference between the bending rigidity of the first adhesive layer PSA1 or the front surface S11 of the first adhesive layer PSA1 and the bending rigidity of the second adhesive layer PSA2 or the rear surface S22 of the second adhesive layer PSA2 may be about 15N·cm or more.

[0132] The first adhesive layer PSA1 having a relatively high modulus and a relatively high bending stiffness can substantially prevent the cover member CM or the window of the cover member CM from being damaged when the display device DD is folded, and the second adhesive layer PSA2 having a relatively low modulus and a relatively low bending stiffness can substantially prevent bright spots from being generated due to impact applied to the display panel DP.

[0133] Figure 8 is a perspective view of an embodiment of an adhesive layer. Figures 9 to 12 is a graph showing the modulus of embodiments of the adhesive layer. Figures 9 to 12 , the vertical axis represents the modulus or bending rigidity, and the horizontal axis represents the position in the first direction D1.

[0134] Reference Figure 8 , Figure 1 An adhesive layer PSA3 may be provided between the cover member CM and the display panel DP. The adhesive layer PSA3 has a front surface S1 facing the cover member CM and a rear surface S2 facing the display panel DP. The front surface S1 of the adhesive layer PSA3 may be in direct contact with the cover member CM or a window of the cover member CM. The rear surface S2 of the adhesive layer PSA3 may be in direct contact with the display panel DP or the thin film encapsulation layer 350 of the display panel DP. Since the adhesive layer PSA3 is formed as a single layer, the adhesive layer PSA3 does not include an interface between the front surface S1 and the rear surface S2 of the adhesive layer PSA3.

[0135] The adhesive layer PSA3 may include a first region and a second region, which are defined to be arranged at different positions from each other in the first direction D1, and may have different moduli from each other.

[0136] Reference Fig. 9 , the front surface S1 of the adhesive layer PSA3 has a modulus or bending stiffness higher than the modulus or bending stiffness of the rear surface S2. At the first region R1 throughout the adhesive layer PSA3, the adhesive layer PSA3 may have a modulus or bending stiffness that gradually decreases in a first direction D1, the first direction D1 being a direction from the front surface S1 toward the rear surface S2. The modulus change slope may be the largest at a first point P1 between the front surface S1 and the rear surface S2, for example, may be the largest at a substantially equal distance from the front surface S1 and the rear surface S2, and the modulus change slope may gradually decrease as it moves away from the first point P1.

[0137] The modulus of the adhesive layer PSA3 at the front surface S1 may be greater than or equal to about 100 KPa and less than or equal to about 1000 KPa, and the modulus of the adhesive layer PSA3 at the rear surface S2 may be about 100 KPa or less. The difference between the modulus of the adhesive layer PSA3 at the front surface S1 and the modulus of the adhesive layer PSA3 at the rear surface S2 may be about 100 KPa or more.

[0138] The adhesive layer PSA3 has a higher bending rigidity at the front surface S1 than at the rear surface S2. The adhesive layer PSA3 may have a bending rigidity that gradually decreases in the first direction D1. The bending rigidity of the adhesive layer PSA3 at the front surface S1 may be greater than or equal to about 30 N·cm and less than or equal to about 50 N·cm, and the bending rigidity of the adhesive layer PSA3 at the rear surface S2 may be greater than or equal to about 15 N·cm and less than or equal to about 30 N·cm. The difference between the bending rigidity of the adhesive layer PSA3 at the front surface S1 and the bending rigidity of the adhesive layer PSA3 at the rear surface S2 may be about 15 N·cm or more.

[0139] The front surface S1 of the adhesive layer PSA3 having a relatively high modulus and a relatively high bending stiffness can prevent or at least reduce the cover member CM or the window of the cover member CM from being damaged when the display device DD is folded, and the rear surface S2 of the adhesive layer PSA3 having a relatively low modulus and a relatively low bending stiffness can prevent or at least reduce the bright spots generated by the impact applied to the display panel DP. Moreover, since the adhesive layer PSA3 is formed as a single layer, the manufacturing process of the display device DD can be reduced (simplified). In addition, since the single adhesive layer PSA3 can prevent or at least reduce the possibility of damage in the case of Figure 6 The reflection or refraction of light occurring at the interface between the adhesive layers PSA1 and PSA2 can improve the image quality of the display device DD. In addition, assuming that the plurality of adhesive layers can be peeled off from each other, the single adhesive layer PSA3 can be strong against stress.

[0140] Reference Fig.10 , the front surface S1 of the adhesive layer PSA3 has a modulus lower than the modulus of the rear surface S2. The adhesive layer PSA3 may have a modulus that gradually increases in the first direction D1. The modulus of the adhesive layer PSA3 at the front surface S1 may be about 100 KPa or less, and the modulus of the adhesive layer PSA3 at the rear surface S2 may be greater than or equal to about 100 KPa and less than or equal to about 1000 KPa. The difference between the modulus of the adhesive layer PSA3 at the front surface S1 and the modulus of the adhesive layer PSA3 at the rear surface S2 may be about 100 KPa or more.

[0141] The adhesive layer PSA3 has a lower bending rigidity at the front surface S1 than at the rear surface S2. The adhesive layer PSA3 may have a bending rigidity that gradually increases in the first direction D1. The bending rigidity of the adhesive layer PSA3 at the rear surface S2 may be greater than or equal to about 30N·cm and less than or equal to about 50N·cm, and the bending rigidity of the adhesive layer PSA3 at the front surface S1 may be greater than or equal to about 15N·cm and less than or equal to about 30N·cm. The difference between the bending rigidity of the adhesive layer PSA3 at the front surface S1 and the bending rigidity of the adhesive layer PSA3 at the rear surface S2 may be about 15N·cm or more.

[0142] Reference Fig.11 , the front surface S1 of the adhesive layer PSA3 has a modulus or bending stiffness higher than the modulus or bending stiffness of the rear surface S2. The adhesive layer PSA3 may have a substantially constant modulus or bending stiffness at the second region R2 from the front surface S1 to the second point P2. The adhesive layer PSA3 may have a modulus or bending stiffness that gradually decreases in the first direction D1 at the first region R1 from the second point P2 to the third point P3. The adhesive layer PSA3 may have a substantially constant modulus or bending stiffness at the third region R3 from the third point P3 to the rear surface S2. In the entire regions R1, R2 and R3 of the adhesive layer PSA3, the adhesive layer PSA3 has a continuous modulus or bending stiffness.

[0143] The modulus of the adhesive layer PSA3 at the second region R2 may be greater than or equal to about 100 KPa and less than or equal to about 1000 KPa, and the modulus of the adhesive layer PSA3 at the third region R3 may be about 100 KPa or less. The difference between the modulus of the adhesive layer PSA3 at the second region R2 and the modulus of the adhesive layer PSA3 at the third region R3 may be about 100 KPa or more.

[0144] The bending stiffness of the adhesive layer PSA3 at the second region R2 may be greater than or equal to about 30 N·cm and less than or equal to about 50 N·cm, and the bending stiffness of the adhesive layer PSA3 at the third region R3 may be greater than or equal to about 15 N·cm and less than or equal to about 30 N·cm. The difference between the bending stiffness of the adhesive layer PSA3 at the second region R2 and the bending stiffness of the adhesive layer PSA3 at the third region R3 may be about 15 N·cm or more.

[0145] Reference Fig.12, the front surface S1 of the adhesive layer PSA3 has a modulus or bending stiffness lower than the modulus or bending stiffness of the rear surface S2. The adhesive layer PSA3 may have a substantially constant modulus or bending stiffness at the second region R2 from the front surface S1 to the second point P2. The adhesive layer PSA3 may have a modulus or bending stiffness that gradually increases in the first direction D1 at the first region R1 from the second point P2 to the third point P3. The adhesive layer PSA3 may have a substantially constant modulus or bending stiffness at the third region R3 from the third point P3 to the rear surface S2. In the entire regions R1, R2 and R3 of the adhesive layer PSA3, the adhesive layer PSA3 has a continuous modulus or bending stiffness.

[0146] The modulus of the adhesive layer PSA3 at the second region R2 may be about 100 KPa or less, and the modulus of the adhesive layer PSA3 at the third region R3 may be about 100 KPa or more and about 1000 KPa or less. The difference between the modulus of the adhesive layer PSA3 at the second region R2 and the modulus of the adhesive layer PSA3 at the third region R3 may be about 100 KPa or more.

[0147] The bending stiffness of the adhesive layer PSA3 at the second region R2 may be greater than or equal to about 15 N·cm and less than or equal to about 30 N·cm, and the bending stiffness of the adhesive layer PSA3 at the third region R3 may be greater than or equal to about 30 N·cm and less than or equal to about 50 N·cm. The difference between the bending stiffness of the adhesive layer PSA3 at the second region R2 and the bending stiffness of the adhesive layer PSA3 at the third region R3 may be about 15 N·cm or more.

[0148] Fig.13 is a graph showing the modulus of another embodiment of multiple bonding layers.

[0149] Reference Fig.13 , Figure 1 A plurality of adhesive layers PSA1, PSA2, and PSA3 may be provided between the cover member CM and the display panel DP. The third adhesive layer PSA3 may be disposed between the first adhesive layer PSA1 and the second adhesive layer PSA2. The third adhesive layer PSA3 may be a reference Figures 8 to 12 The adhesive layer PSA3 is shown. The first adhesive layer PSA1 and the second adhesive layer PSA2 form an interface with the third adhesive layer PSA3. The front surface S4 of the first adhesive layer PSA1 may be in direct contact with the cover member CM or the window of the cover member CM. The rear surface S5 of the second adhesive layer PSA2 may be in direct contact with the display panel DP or the thin film encapsulation layer 350 of the display panel DP.

[0150] At the interface between the first adhesive layer PSA1 and the third adhesive layer PSA3 and at the interface between the second adhesive layer PSA2 and the third adhesive layer PSA3, the modulus or bending stiffness of the adhesive layers PSA1, PSA2 and PSA3 may not be continuous. The modulus or bending stiffness of the first adhesive layer PSA1 may be higher than the modulus or bending stiffness of the third adhesive layer PSA3. The modulus or bending stiffness of the second adhesive layer PSA2 may be lower than the modulus or bending stiffness of the third adhesive layer PSA3. In the first direction D1 as the thickness direction, the first adhesive layer PSA1 and the second adhesive layer PSA2 may each have a substantially constant modulus.

[0151] Figures 14 to 16 : is a graph showing the modulus of other embodiments of the adhesive layer.

[0152] Reference Fig.14 , the front surface S1 and the rear surface S2 of the adhesive layer PSA3 have a modulus or bending stiffness higher than the modulus or bending stiffness of the fourth point P4 therebetween. The adhesive layer PSA3 may have a modulus or bending stiffness that gradually decreases in the first direction D1 at the (1-1)th zone R1-1 from the front surface S1 to the fourth point P4. The adhesive layer PSA3 may have a modulus or bending stiffness that gradually increases in the first direction D1 at the (1-2)th zone R1-2 from the fourth point P4 to the rear surface S2. The modulus variation slope may be the largest at the fifth point P5 between the front surface S1 and the fourth point P4 and at the sixth point P6 between the rear surface S2 and the fourth point P4, and may gradually decrease as it moves away from the fifth point P5 and the sixth point P6.

[0153] The modulus of the adhesive layer PSA3 at the front surface S1 and the rear surface S2 may be greater than or equal to about 100 KPa and less than or equal to about 1000 KPa, and the modulus of the adhesive layer PSA3 at the fourth point P4 may be about 100 KPa or less. The difference between the modulus of the adhesive layer PSA3 at the front surface S1 and the rear surface S2 and the modulus of the adhesive layer PSA3 at the fourth point P4 may be about 100 KPa or more.

[0154] The bending rigidity of the adhesive layer PSA3 at the front surface S1 and the rear surface S2 may be greater than or equal to about 30 N·cm and less than or equal to about 50 N·cm, and the bending rigidity of the adhesive layer PSA3 at the fourth point P4 may be greater than or equal to about 15 N·cm and less than or equal to about 30 N·cm. The difference between the bending rigidity of the adhesive layer PSA3 at the front surface S1 and the rear surface S2 and the bending rigidity of the adhesive layer PSA3 at the fourth point P4 may be about 15 N·cm or more.

[0155] Reference Fig.15, the front surface S1 and the back surface S2 of the adhesive layer PSA3 have a modulus or bending stiffness higher than the modulus or bending stiffness of the fourth point P4 therebetween. The adhesive layer PSA3 may have a substantially constant modulus or bending stiffness within a predetermined distance from the front surface S1, within a predetermined distance from the fourth point P4, and within a predetermined distance from the back surface S2.

[0156] Reference Fig.16 , the front surface S1 and the rear surface S2 of the adhesive layer PSA3 have a modulus or bending stiffness lower than the modulus or bending stiffness of the fourth point P4 therebetween. The adhesive layer PSA3 may have a modulus or bending stiffness that gradually decreases in the first direction D1 at the (1-1) zone R1-1 from the fourth point P4 to the rear surface S2. The adhesive layer PSA3 may have a modulus or bending stiffness that gradually increases in the first direction D1 at the (1-2) zone R1-2 from the front surface S1 to the fourth point P4. The modulus variation slope is the largest at the fifth point P5 between the front surface S1 and the fourth point P4 and at the sixth point P6 between the rear surface S2 and the fourth point P4, and may gradually decrease as it moves away from the fifth point P5 and the sixth point P6.

[0157] The modulus of the adhesive layer PSA3 at the front surface S1 and the rear surface S2 may be about 100 KPa or less, and the modulus of the adhesive layer PSA3 at the fourth point P4 may be about 100 KPa or more and about 1000 KPa or less. The difference between the modulus of the adhesive layer PSA3 at the front surface S1 and the rear surface S2 and the modulus of the adhesive layer PSA3 at the fourth point P4 may be about 100 KPa or more.

[0158] The bending rigidity of the adhesive layer PSA3 at the front surface S1 and the rear surface S2 may be greater than or equal to about 15 N·cm and less than or equal to about 30 N·cm, and the bending rigidity of the adhesive layer PSA3 at the fourth point P4 may be greater than or equal to about 30 N·cm and less than or equal to about 50 N·cm. The difference between the bending rigidity of the adhesive layer PSA3 at the front surface S1 and the rear surface S2 and the bending rigidity of the adhesive layer PSA3 at the fourth point P4 may be about 15 N·cm or more.

[0159] The adhesive layer PSA3 may have a substantially constant modulus or bending stiffness within a predetermined distance from the front surface S1 , within a predetermined distance from the fourth point P4 , and within a predetermined distance from the back surface S2 .

[0160] Fig.17 is a perspective view of another embodiment of an adhesive layer. Figures 18 to 20 is a graph showing the modulus of yet other embodiments of the adhesive layer. Figures 18 to 20 , the vertical axis represents the modulus or bending rigidity, and the horizontal axis represents the position in the second direction D2.

[0161] Reference Figure 1 and Fig.17 , a folding line FL along which the display device DD is folded may pass through the center of the display device DD and may be parallel to the third direction D3. Accordingly, the display device DD, the display panel DP, the cover member CM, and the adhesive layer PSA3 have a folding area FA adjacent to the folding line FL and a non-folding area NFA located on the opposite side of the folding area FA.

[0162] The adhesive layer PSA3 may be arranged between the cover member CM and the display panel DP. The adhesive layer PSA3 has a front surface S1 facing the cover member CM and a rear surface S2 facing the display panel DP. The front surface S1 of the adhesive layer PSA3 may be in direct contact with the cover member CM or a window of the cover member CM. The rear surface S2 of the adhesive layer PSA3 may be in direct contact with the display panel DP or the thin film encapsulation layer 350 of the display panel DP. In the absence of an interface between the front surface S1 and the rear surface S2, the adhesive layer PSA3 is formed as a single layer. The adhesive layer PSA3 has a first side surface S3 and a second side surface S4 extending between the front surface S1 and the rear surface S2. The first side surface S3 and the second side surface S4 may extend in a third direction D3 intersecting the second direction D2. The first side surface S3 and the second side surface S4 may be formed to be parallel to the folding line FL. There may be no interface between the first side surface S3 and the second side surface S4 of the adhesive layer PSA3.

[0163] Reference Fig.18 , the folding area FA of the adhesive layer PSA3 has a modulus or bending stiffness lower than the modulus or bending stiffness of the non-folding area NFA. The adhesive layer PSA3 may have a modulus or bending stiffness that gradually decreases from the first side surface S3 toward the seventh point P7 corresponding to the folding line FL. The adhesive layer PSA3 may have a modulus or bending stiffness that gradually increases from the seventh point P7 to the second side surface S4. The modulus change slope may be the largest at the eighth point P8 between the first side surface S3 and the seventh point P7 and at the ninth point P9 between the second side surface S4 and the seventh point P7, and gradually decreases as it moves away from the eighth point P8 and the ninth point P9. The eighth point P8 and the ninth point P9 may correspond to the boundary between the folding area FA and the non-folding area NFA.

[0164] The modulus of the adhesive layer PSA3 at the non-folding area NFA may be greater than or equal to about 100 KPa and less than or equal to about 1000 KPa, and the modulus of the adhesive layer PSA3 at the folding area FA may be about 100 KPa or less. The difference between the modulus of the adhesive layer PSA3 at the non-folding area NFA and the modulus of the adhesive layer PSA3 at the folding area FA may be about 100 KPa or more.

[0165] The modulus of the adhesive layer PSA3 at the first side surface S3 and the second side surface S4 may be greater than or equal to about 100 KPa and less than or equal to about 1000 KPa, and the modulus of the adhesive layer PSA3 at the seventh point P7 may be about 100 KPa or less. The difference between the modulus of the adhesive layer PSA3 at the first side surface S3 and the second side surface S4 and the modulus of the adhesive layer PSA3 at the seventh point P7 may be about 100 KPa or more.

[0166] The bending stiffness of the adhesive layer PSA3 at the non-folding area NFA may be greater than or equal to about 30 N·cm and less than or equal to about 50 N·cm, and the bending stiffness of the adhesive layer PSA3 at the folding area FA may be greater than or equal to about 15 N·cm and less than or equal to about 30 N·cm. The difference between the bending stiffness of the adhesive layer PSA3 at the non-folding area NFA and the bending stiffness of the adhesive layer PSA3 at the folding area FA may be about 15 N·cm or more.

[0167] The bending stiffness of the adhesive layer PSA3 at the first side surface S3 and the second side surface S4 may be greater than or equal to about 30 N·cm and less than or equal to about 50 N·cm, and the bending stiffness of the adhesive layer PSA3 at the seventh point P7 may be greater than or equal to about 15 N·cm and less than or equal to about 30 N·cm. The difference between the bending stiffness of the adhesive layer PSA3 at the first side surface S3 and the second side surface S4 and the bending stiffness of the adhesive layer PSA3 at the seventh point P7 may be about 15 N·cm or more.

[0168] Reference Fig.19 , the adhesive layer PSA3 may have a substantially constant modulus or bending stiffness within a predetermined distance from the first side surface S3, within a predetermined distance from the seventh point P7, and within a predetermined distance from the second side surface S4. More specifically, the adhesive layer PSA3 may have a substantially constant modulus or bending stiffness from the first side surface S3 to the tenth point P10. From the tenth point P10 to the twelfth point P12, the adhesive layer PSA3 may have a gradually decreasing modulus or bending stiffness. From the twelfth point P12 to the thirteenth point P13, the adhesive layer PSA3 may have a substantially constant modulus or bending stiffness. From the thirteenth point P13 to the eleventh point P11, the adhesive layer PSA3 may have a gradually increasing modulus or bending stiffness. From the eleventh point P11 to the second side surface S4, the adhesive layer PSA3 may have a substantially constant modulus or bending stiffness.

[0169] The adhesive layer PSA3 having a relatively high modulus and a relatively high bending stiffness at the non-folding area NFA can improve the impact resistance of the display device DD. The adhesive layer PSA3 having a relatively low modulus and a relatively low bending stiffness at the folding area FA can alleviate the stress generated by the folding of the display device DD. Moreover, a single adhesive layer PSA3 can reduce the manufacturing process of the display device DD. In addition, because a single adhesive layer PSA3 can prevent or at least reduce the reflection or refraction of light that may occur at the interface between multiple adhesive layers, the image quality of the display device DD can be improved.

[0170] Reference Fig. 20 , the folding area FA of the adhesive layer PSA3 has a modulus or bending stiffness higher than the modulus or bending stiffness of the non-folding area NFA. The adhesive layer PSA3 may have a modulus or bending stiffness that gradually increases from the first side surface S3 to the seventh point P7 corresponding to the folding line FL. The adhesive layer PSA3 may have a modulus or bending stiffness that gradually decreases from the seventh point P7 to the second side surface S4.

[0171] The modulus of the adhesive layer PSA3 at the folding area FA may be greater than or equal to about 100 KPa and less than or equal to about 1000 KPa, and the modulus of the adhesive layer PSA3 at the non-folding area NFA may be about 100 KPa or less. The difference between the modulus of the adhesive layer PSA3 at the folding area FA and the modulus of the adhesive layer PSA3 at the non-folding area NFA may be about 100 KPa or more.

[0172] The modulus of the adhesive layer PSA3 at the seventh point P7 may be greater than or equal to about 100 KPa and less than or equal to about 1000 KPa, and the modulus of the adhesive layer PSA3 at the first side surface S3 and the second side surface S4 may be about 100 KPa or less. The difference between the modulus of the adhesive layer PSA3 at the first side surface S3 and the second side surface S4 and the modulus of the adhesive layer PSA3 at the seventh point P7 may be about 100 KPa or more.

[0173] The bending stiffness of the adhesive layer PSA3 at the folding area FA may be greater than or equal to about 30 N·cm and less than or equal to about 50 N·cm, and the bending stiffness of the adhesive layer PSA3 at the non-folding area NFA may be greater than or equal to about 15 N·cm and less than or equal to about 30 N·cm. The difference between the bending stiffness of the adhesive layer PSA3 at the non-folding area NFA and the bending stiffness of the adhesive layer PSA3 at the folding area FA may be about 15 N·cm or more.

[0174] The bending stiffness of the adhesive layer PSA3 at the seventh point P7 may be greater than or equal to about 30 N·cm and less than or equal to about 50 N·cm, and the bending stiffness of the adhesive layer PSA3 at the first side surface S3 and the second side surface S4 may be greater than or equal to about 15 N·cm and less than or equal to about 30 N·cm. The difference between the bending stiffness of the adhesive layer PSA3 at the seventh point P7 and the bending stiffness of the adhesive layer PSA3 at the first side surface S3 and the second side surface S4 may be about 15 N·cm or more.

[0175] Reference Fig. 20 , the adhesive layer PSA3 may have a substantially constant modulus or bending stiffness within a predetermined distance from the first side surface S3, within a predetermined distance from the seventh point P7, and within a predetermined distance from the second side surface S4. More specifically, the adhesive layer PSA3 may have a substantially constant modulus or bending stiffness from the first side surface S3 to the tenth point P10, from the twelfth point P12 to the thirteenth point P13, and from the eleventh point P11 to the second side surface S4.

[0176] The third adhesive layer PSA3 having a relatively low modulus and a relatively low bending stiffness at the non-folding area NFA can substantially prevent the bright spots generated by the impact applied to the display panel DP. The third adhesive layer PSA3 having a relatively high modulus and a relatively high bending stiffness at the folding area FA can substantially prevent or at least reduce the buckling caused by the shear force of the adhesive layer PSA3. The shear force may be generated when the display device DD is folded, and overlaps at some areas of the display device DD (such as the non-folding area NFA). Therefore, the display device DD may not be deformed. Moreover, a single adhesive layer PSA3 can simplify the manufacturing process of the display device DD. In addition, because a single adhesive layer PSA3 can prevent or at least reduce the reflection or refraction of light that may occur at the interface between multiple adhesive layers, the image quality of the display device DD can be improved.

[0177] Figures 21 to 28 are graphs each showing the concentration of an initiator contained in a composition before curing the adhesive layer according to an embodiment. Figures 21 to 28 , the vertical axis represents the concentration of the initiator, and the horizontal axis represents the position in the first direction D1.

[0178] In an embodiment, the adhesive layer PSA3 may be formed by curing a photocurable composition including a photocurable resin. The photocurable resin (more specifically, an ultraviolet (UV) curable resin) includes a polymer material system or a composition system that causes physical and chemical changes by light energy. The photocuring may include photopolymerization of a monomer or a photosensitive polymer (i.e., a prepolymer) into a polymer or optical crosslinking of converting a polymer into a three-dimensional crosslinked polymer through a crosslinking reaction.

[0179] The UV curable composition may include a prepolymer, a multifunctional monomer (which is a diluent), and a photoinitiator component, and may generally include 50% to 60% of a polymer, 30% to 40% of a multifunctional monomer, and 1% to 10% of a photoinitiator.

[0180] The multifunctional monomer is used as a diluent for the UV curable composition to reduce the viscosity and becomes part of the cured structure after curing. The multifunctional monomer may include a monofunctional acrylic, a difunctional acrylic, or a multifunctional acrylic.

[0181] The prepolymer is a main component constituting the skeleton of the UV-curable composition and determines the physical properties (hardness, adhesion, electrical properties, flexibility, chemical resistance, etc.) of the adhesive layer PSA3. The prepolymer may include at least one selected from the group consisting of unsaturated polyester resins, polyester acrylate resins, polyurethane acrylate resins, and epoxy acrylate resins.

[0182] A photoinitiator (more specifically, a UV initiator) is added to a UV curable resin in a small amount, and initiates a polymerization reaction upon receiving UV rays emitted from a UV lamp.

[0183] The photocuring reaction may be affected by light intensity, light wavelength, light exposure time, composition thickness, initiator type and concentration, etc.

[0184] According to an embodiment, the composition for forming the adhesive layer PSA 3 includes at least one photoinitiator having different concentrations in the first direction D1 .

[0185] Reference Fig.21 , the photocurable composition (hereinafter referred to as "composition") may include a first composition applied from the front surface S1 to the first point P1 and a second composition applied from the first point P1 to the rear surface S2.

[0186] The first component includes a photocurable resin (hereinafter referred to as "resin") and a first photoinitiator (hereinafter referred to as "initiator"). The second component includes a resin and a second photoinitiator (hereinafter referred to as "initiator"). The first component and the second component may include substantially the same resin. The first initiator and the second initiator initiate polymerization with light having a first wavelength and light having a second wavelength, respectively. The first wavelength and the second wavelength may be different from each other. The first initiator initiates polymerization by light having the first wavelength, but does not initiate polymerization by light having the second wavelength. The second initiator initiates polymerization by light having the second wavelength, but does not initiate polymerization by light having the first wavelength.

[0187] Short wavelength initiators initiate polymerization with light having a short wavelength in the range of about 220 nm to about 320 nm, but not with light having a wavelength of about 320 nm or greater. Intermediate wavelength initiators initiate polymerization with light having an intermediate wavelength in the range of about 260 nm to about 380 nm, but not with light having a wavelength of about 380 nm or greater. Long wavelength initiators initiate polymerization with light having a long wavelength in the range of about 340 nm to about 440 nm, but not with light having a wavelength of about 440 nm or greater.

[0188] The first initiator may include any one of a short wavelength initiator, an intermediate wavelength initiator, and a long wavelength initiator, and the second initiator may include another one of the short wavelength initiator, the intermediate wavelength initiator, and the long wavelength initiator.

[0189] For example, initiators having a relatively short wavelength activation band may include, for example 184, 250, 369, 500, 651, 754, 907, 1300, 2959, 1173 and MBF, while initiators with relatively long wavelength activation bands may include, for example 784, 819, 2022, 2100 and TPO.

[0190] Reference Fig.21 , the first initiator has a concentration of De1 from the front surface S1 to the first point P1, but not included from the first point P1 to the back surface S2. The second initiator is not included from the front surface S1 to the first point P1, but the second initiator has a concentration of De2 from the first point P1 to the back surface S2. De1 and De2 may be substantially the same as or different from each other.

[0191] Reference Fig. 22 , the first initiator has a concentration of De1 at the front surface S1, and the concentration decreases as it approaches the rear surface S2. The second initiator has a concentration of De2 at the rear surface S2, and the concentration decreases as it approaches the front surface S1. The concentrations of De1 and De2 may be substantially the same as or different from each other. The first initiator and the second initiator may each have a substantially constant concentration near the front surface S1 and the rear surface S2.

[0192] Fig.21 The concentration diagram may correspond to a state immediately after application of the first component and the second component, Fig. 22 This may correspond to a state in which the first initiator and the second initiator are each diffused beyond the first point P1 after the first component and the second component are applied.

[0193] Reference Fig.21 and Fig. 22 , the curing of the area adjacent to the front surface S1 is mainly affected by the first initiator, and the curing of the area adjacent to the rear surface S2 is mainly affected by the second initiator. Accordingly, the area adjacent to the front surface S1 can be cured by irradiating the area with light having a first wavelength, which only activates the first initiator, and the area adjacent to the rear surface S2 can be cured by irradiating the area with light having a second wavelength, which only activates the second initiator. In addition, the degree of curing of the area adjacent to the front surface S1 can be determined based on the intensity of the light having the first wavelength, the irradiation time of the light, and the concentration of the first initiator. In addition, independently of the degree of curing of the area adjacent to the front surface S1, the degree of curing of the area adjacent to the rear surface S2 can be determined based on the intensity of the light having the second wavelength, the irradiation time of the light, and the concentration of the second initiator. For example, they can be cured to have a reference Figures 8 to 12 The modulus or bending stiffness shown in .

[0194] Reference Fig.23 , the composition includes a first composition applied from the front surface S1 to the first point P1 and a second composition applied from the first point P1 to the back surface S2.

[0195] The first component includes a resin and a first initiator having a concentration of De1. The second component includes a resin and a first initiator having a concentration of De2. The first component and the second component may include substantially the same resin. The concentration of De1 and the concentration of De2 of the first initiator in the first component and the second component are different from each other. Either of the concentration of De1 and the concentration of De2 may be zero.

[0196] The first initiator has a concentration of De1 from the front surface S1 to the first point P1, and has a concentration of De2 from the first point P1 to the rear surface S2. The first initiator may not be included from the first point P1 to the rear surface S2. Conversely, the first initiator may not be included from the front surface S1 to the first point P1.

[0197] Reference Fig.24 , the first initiator has a concentration of De1 at the front surface S1, and the concentration decreases as it approaches the rear surface S2. Accordingly, the first initiator may have a concentration of De2 at the rear surface S2. The first initiator may have a substantially constant concentration near the front surface S1 and the rear surface S2.

[0198] Fig.23 The concentration diagram may correspond to a state immediately after application of the first component and the second component, Fig.24 This may correspond to a state in which the first initiator diffuses beyond the first point P1 after the first component and the second component are applied.

[0199] Reference Fig.23 and Fig.24 , the concentration of the first initiator varies along the first direction D1. Accordingly, the degree of curing of each region adjacent to the front surface S1 and the rear surface S2 may vary according to the concentration of the first initiator. Typically, a portion having a relatively high concentration of the initiator is cured to have a relatively high modulus or bending stiffness. For example, it may be cured to have Figures 8 to 12 The modulus or bending stiffness shown in .

[0200] Reference Fig.25 The composition includes a first composition applied from the front surface S1 to a fifth point P5, a second composition applied from the fifth point P5 to a sixth point P6, and a third composition applied from the sixth point P6 to the rear surface S2.

[0201] The first component includes a resin and a first initiator. The second component includes a resin and a second initiator. The third component includes a resin and a third initiator. The first component, the second component, and the third component may each include substantially the same resin. The first initiator, the second initiator, and the third initiator may have activation bands different from each other.

[0202] For example, the first initiator may include any one of a short wavelength initiator, an intermediate wavelength initiator, and a long wavelength initiator, the second initiator may include another one of the short wavelength initiator, the intermediate wavelength initiator, and the long wavelength initiator, and the third initiator may include the remaining one of the short wavelength initiator, the intermediate wavelength initiator, and the long wavelength initiator.

[0203] Alternatively, the first initiator and the third initiator may have an activation band different from the second initiator, and the first initiator and the third initiator may have substantially the same activation band. The first initiator and the third initiator may include substantially the same material.

[0204] Reference Fig.25 , the first initiator has a concentration of De1 from the front surface S1 to the fifth point P5, and is not included in the remaining area. The second initiator has a concentration of De2 from the fifth point P5 to the sixth point P6, and is not included in the remaining area. The third initiator has a concentration of De3 from the sixth point P6 to the rear surface S2, and is not included in the remaining area. The concentration of De1, the concentration of De2, and the concentration of De3 may be substantially the same as each other or different from each other. The concentration of De1 and the concentration of De3 may be substantially the same as each other and may be different from the concentration of De2.

[0205] Reference Fig.26, the first initiator has a concentration of De1 at the front surface S1, and the concentration decreases as it approaches the rear surface S2. The second initiator has a concentration of De2 at the fourth point P4, and the concentration decreases as it approaches the front surface S1 or the rear surface S2. The third initiator has a concentration of De3 at the rear surface S2, and the concentration decreases as it approaches the front surface S1. The first initiator, the second initiator, and the third initiator may have substantially constant concentrations near the front surface S1, the fourth point P4, and the rear surface S2, respectively.

[0206] Fig.25 The concentration graph may correspond to a state immediately after application of the first component, the second component, and the third component, Fig.26 This may correspond to a state in which the first component, the second component, and the third component are each diffused after the first component, the second component, and the third component are applied.

[0207] Reference Fig.25 and Fig.26 , the curing of the area adjacent to the front surface S1 is mainly affected by the first initiator, the curing of the area adjacent to the fourth point P4 is mainly affected by the second initiator, and the curing of the area adjacent to the rear surface S2 is mainly affected by the third initiator. Accordingly, the curing degrees of the areas adjacent to the front surface S1, the fourth point P4 and the rear surface S2 can be determined independently. For example, they can be cured to have Figures 14 to 16 Thus, the modulus or bending rigidity can be adjusted by adjusting the type and / or concentration of the initiator contained in each composition according to the position in the adhesive layer.

[0208] Reference Fig. 27 The composition includes a first composition applied from the front surface S1 to a fifth point P5, a second composition applied from the fifth point P5 to a sixth point P6, and a third composition applied from the sixth point P6 to the rear surface S2.

[0209] The first component includes a resin and a first initiator having a concentration of De1. The second component includes a resin and a first initiator having a concentration of De2. The third component includes a resin and a first initiator having a concentration of De3. The first component, the second component, and the third component may contain substantially the same resin. The concentration of De1 and the concentration of De3 of the first initiator of the first component and the third component are different from the concentration of De2 of the first initiator of the second component. The concentration of De1 and the concentration of De3 of the first initiator of the first component and the third component may be substantially the same as or different from each other. The concentration of De1 and the concentration of De3 of the first initiator of the first component and the third component may be zero. Conversely, the concentration of De2 of the first initiator of the second component may be zero.

[0210] Reference Fig. 27 , the first initiator has a concentration of De1 from the front surface S1 to the fifth point P5, has a concentration of De2 from the fifth point P5 to the sixth point P6, and has a concentration of De3 from the sixth point P6 to the back surface S2.

[0211] Reference Fig.28 , the first initiator has the highest concentration of De2 at the fourth point P4, and the concentration decreases as it approaches the front surface S1 or the rear surface S2. However, the embodiment is not limited thereto, and the first initiator may have the lowest concentration of De2 at the fourth point P4, and the concentration may increase as it approaches the front surface S1 or the rear surface S2.

[0212] Fig. 27 The concentration graph may correspond to a state immediately after application of the first component, the second component, and the third component, Fig.28 This may correspond to a state in which the first initiator is diffused after the first component, the second component, and the third component are applied.

[0213] Reference Fig. 27 and Fig.28 , the concentration of the first initiator varies along the first direction D1. Accordingly, the curing degrees of the regions adjacent to the front surface S1, the fourth point P4, and the rear surface S2 may be different from each other according to the concentration of the first initiator. For example, it may be cured to have Figures 14 to 16 The modulus or bending stiffness shown in .

[0214] FIG. 29A to FIG. 29G It is a cross-sectional view showing an embodiment of a method for producing an adhesive layer.

[0215] Reference Fig.29A , a first release film 510 on which an adhesive layer is to be formed is prepared.

[0216] Reference Fig.29B , the first component 410 is applied on the first release film 510. The first component 410 may correspond to the reference Fig.21 The first composition is described as being applied from the front surface S1 to the first point P1.

[0217] Reference Fig.29C , the second component 420 is applied on the first component 410. The second component 420 may correspond to the reference Fig.21 The second composition is described as being applied from the first point P1 to the back surface S2.

[0218] Reference Fig.29D, the first initiator included in the first composition 410 and the second initiator included in the second composition 420 are diffused so that the concentrations of the first initiator and the second initiator gradually change. The concentrations of the first initiator and the second initiator may correspond to Fig. 22 The concentrations shown in .

[0219] Reference Fig.29E , the UV lamp 610 emits UV rays 611 to the uncured composition 430. Only the first initiator initiates a polymerization reaction by the UV rays 611 having the first wavelength. Depending on the desired modulus and bending stiffness at the front surface S1, the intensity and irradiation time of the UV rays 611 having the first wavelength and the concentration of the first initiator may be determined.

[0220] Reference Fig.29F , the UV lamp 620 emits UV rays 621 to the partially cured composition 440. Only the second initiator initiates a polymerization reaction by the UV rays 621 having the second wavelength. Depending on the desired modulus and bending stiffness at the rear surface S2, the intensity and irradiation time of the UV rays 621 having the second wavelength and the concentration of the second initiator may be determined.

[0221] The curing with the UV rays 621 having the second wavelength may be performed before the curing with the UV rays 611 having the first wavelength, or the curing with the UV rays 611 having the first wavelength and the curing with the UV rays 621 having the second wavelength may be performed simultaneously.

[0222] Reference Figure 29G , attaching the second peeling film 520 on the cured composition 450. The second peeling film 520 may be disposed on the uncured composition 430, and then curing with the UV rays 611 having the first wavelength and curing with the UV rays 621 having the second wavelength may be performed thereon. After removing the first peeling film 510 and the second peeling film 520, the cured composition 450 as an adhesive layer is attached between the display panel DP and the cover member CM.

[0223] FIG. 30A to FIG. 30C It is a cross-sectional view showing another embodiment of the method for producing an adhesive layer.

[0224] Reference Fig. 30A , the first component 410 is applied on the first release film 510. The first component 410 may correspond to the reference Fig.21 The first component 420 is applied from the front surface S1 to the first point P1 as described above. In addition, the second component 420 is applied on the second release film 520. The second component 420 may correspond to the first component 420 of the reference Fig.21 The second composition is described as being applied from the first point P1 to the back surface S2.

[0225] Reference Fig. 30B , when the first component 410 and the second component 420 face each other, the first release film 510 and the second release film 520 are stacked on each other.

[0226] Reference Fig. 30C , so that the first initiator included in the first composition 410 and the second initiator included in the second composition 420 diffuse, thereby forming a composition in which the concentrations of the first initiator and the second initiator gradually change. The concentrations of the first initiator and the second initiator may correspond to Fig. 22 The concentrations shown in .

[0227] Then, as mentioned above Fig.29E and Fig.29F As described above, curing with the UV rays 611 having the first wavelength and curing with the UV rays 621 having the second wavelength may be performed.

[0228] FIG. 31A to FIG. 31F This is a cross-sectional view showing still another embodiment of the method for producing the adhesive layer.

[0229] Reference Fig.31A , a first initiator 411 is applied on the first release film 510 .

[0230] Reference Fig.31B , the resin 412 is applied on the first initiator 411.

[0231] Reference Fig. 31C , a second initiator 421 is applied on the second release film 520 , and a resin 422 is applied on the second initiator 421 .

[0232] Reference Fig.31D , the first initiator 411 diffuses into the resin 412 to form the first component 410 - 1 , and the second initiator 421 also diffuses into the resin 422 to form the second component 420 - 1 .

[0233] Reference Fig.31E , when the first component 410 - 1 and the second component 420 - 1 face each other, the first peeling film 510 and the second peeling film 520 are stacked on each other.

[0234] Reference Fig.31F , the first initiator 411 diffuses into the second composition 420-1, and the second initiator 421 diffuses into the first composition 410-1, thereby forming a composition 430-1 in which the concentrations of the first initiator and the second initiator gradually change. The concentrations of the first initiator and the second initiator may correspond to Fig. 22 The concentration in .

[0235] Then, as mentioned above Fig.29E and Fig.29F As described above, curing with the UV rays 611 having the first wavelength and curing with the UV rays 621 having the second wavelength may be performed.

[0236] FIG. 32A to FIG. 32D It is a cross-sectional view showing still another embodiment of the method for producing the adhesive layer.

[0237] Reference Fig.32A , a first initiator 411 is applied on the first release film 510 , and a resin 412 is applied on the first initiator 411 .

[0238] Reference Fig.32B , so that the first initiator 411 diffuses into the resin 412, thereby forming a composition 410-1 in which the concentration of the first initiator gradually changes. The concentration of the first initiator in the composition 410-1 may correspond to Fig.24 The concentrations shown in .

[0239] Reference Fig.32C , as mentioned above Fig.29E As described above, curing with UV rays 611 having a first wavelength may be performed.

[0240] Reference Fig.32D , the second peeling film 520 is attached on the cured composition 440 - 1. The second peeling film 520 may be disposed on the uncured composition 410 - 1, and then curing with the UV rays 611 having the first wavelength may be performed thereon.

[0241] FIG. 33A to FIG. 33E It is a cross-sectional view showing still another embodiment of the method for producing an adhesive layer.

[0242] Reference Fig.33A , prepare a first release film 510 to be formed into an adhesive layer, and apply the first component 410 on the first release film 510. The first component 410 may correspond to the above reference Fig.25 The first composition is described as being applied from the front surface S1 to the fifth point P5.

[0243] Reference Fig.33B , the second component 420 is applied on the first component 410. The second component 420 may correspond to the reference Fig.25 The second composition is described as being applied from the fifth point P5 to the sixth point P6.

[0244] Reference Fig.33C , the third component 415 is applied on the second component 420. The third component 415 may correspond to the above reference Fig.25The third composition 415 is described as being applied from the sixth point P6 to the rear surface S2. The third composition 415 may be substantially the same as the first composition 410.

[0245] Reference Fig.33D , the first initiator included in the first component 410, the second initiator included in the second component 420, and the third initiator included in the third component 415 diffuse, thereby forming a component 470 in which the concentrations of the first initiator, the second initiator, and the third initiator gradually change in the first direction D1. The concentrations of the first initiator, the second initiator, and the third initiator in the component 470 may correspond to Fig.26 The concentration in .

[0246] Next, for the uncured composition 470, the UV lamp 610 emits UV rays 611 having a first wavelength, the UV lamp 620 emits UV rays 621 having a second wavelength, and the UV lamp 630 emits UV rays 631 having a third wavelength. The first wavelength, the second wavelength, and the third wavelength correspond to an activation band of the first wavelength, an activation band of the second wavelength, and an activation band of the third wavelength, respectively.

[0247] Reference Fig.33E , the second release film 520 is attached on the cured composition 480. The second release film 520 may be disposed on the uncured composition 470, and then curing may be performed thereon.

[0248] Fig.34 and Fig.35 are graphs each showing the concentration of an initiator before curing an adhesive layer according to an embodiment. Fig.34 and Fig.35 , the vertical axis represents the concentration of the initiator, and the horizontal axis represents the position in the second direction D2.

[0249] Reference Fig.34 The composition includes a first composition applied from the first side surface S3 to an eighth point P8, a second composition applied from the eighth point P8 to a ninth point P9, and a third composition applied from the ninth point P9 to the second side surface S4.

[0250] The first component includes a resin and a first initiator. The second component includes a resin and a second initiator. The third component includes a resin and a third initiator. The first component, the second component, and the third component may include substantially the same resin. The first initiator, the second initiator, and the third initiator may have different activation bands. Alternatively, the first initiator and the third initiator may have activation bands different from the activation band of the second initiator, and the first initiator and the third initiator may have substantially the same activation bands. The first initiator and the third initiator may include substantially the same material.

[0251] Reference Fig.34 , the first initiator has a concentration of De1 from the first side surface S3 to the eighth point P8, and is not included in the remaining area. The second initiator has a concentration of De2 from the eighth point P8 to the ninth point P9, and is not included in the remaining area. The third initiator has a concentration of De3 from the ninth point P9 to the second side surface S4, and is not included in the remaining area. The concentration of De1, the concentration of De2, and the concentration of De3 may be substantially the same as each other or different from each other. The concentration of De1 and the concentration of De3 may be substantially the same as each other and may be different from the concentration of De2.

[0252] Reference Fig.35 , the first initiator has a concentration of De1 at the first side surface S3, and the concentration decreases as it approaches the second side surface S4. The second initiator has a concentration of De2 at the seventh point P7, and the concentration decreases as it approaches the first side surface S3 or the second side surface S4. The third initiator has a concentration of De3 at the second side surface S4, and the concentration decreases as it approaches the first side surface S3. The first initiator, the second initiator, and the third initiator may each have a constant concentration near the first side surface S3, the seventh point P7, and the second side surface S4.

[0253] Fig.34 The concentration graph may correspond to a state immediately after application of the first component, the second component, and the third component, Fig.35 This may correspond to a state in which the first component, the second component, and the third component are diffused after the first component, the second component, and the third component are applied.

[0254] Reference Fig.34 and Fig.35 , the curing of the non-folding area NFA is mainly affected by the first initiator and the third initiator, and the curing of the folding area FA is mainly affected by the second initiator. Accordingly, the curing degree of the folding area FA and the non-folding area NFA can be independently determined. For example, it can be cured to have Figures 18 to 20 The modulus or bending stiffness shown in .

[0255] FIG. 36A to FIG. 36E It is a cross-sectional view showing still another embodiment of the method for producing the adhesive layer.

[0256] Reference Fig.36A , prepare a first release film 510 to be formed into an adhesive layer, and apply the first component 410 on the first release film 510. The first component 410 may correspond to the above reference Fig.34 The first composition is described as being applied from the first side surface S3 to the eighth point P8.

[0257] Reference Fig.36B, the second component 420 is applied on the first release film 510 to contact with the first component 410. The second component 420 may correspond to the above reference Fig.34 The second composition is described as being applied from the eighth point P8 to the ninth point P9. The area from the eighth point P8 to the ninth point P9 may correspond to the folding area FA. The area from the eighth point P8 to the ninth point P9 may be larger than the folding area FA and may include the entire folding area FA.

[0258] Reference Fig.36C , the third component 415 is applied on the first release film 510 to contact the second component 420. The third component 415 may correspond to the reference Fig.34 The third composition applied from the ninth point P9 to the second side surface S4 is described.

[0259] Reference Fig.36D , the first initiator included in the first component 410, the second initiator included in the second component 420, and the third initiator included in the third component 415 are diffused so that the concentrations of the first initiator, the second initiator, and the third initiator gradually change in the second direction D2. The concentrations of the first initiator, the second initiator, and the third initiator may correspond to Fig.35 The concentrations shown in .

[0260] Next, for the uncured composition 490, the UV lamp 610 emits UV rays 611 having a first wavelength, the UV lamp 620 emits UV rays 621 having a second wavelength, and the UV lamp 630 emits UV rays 631 having a third wavelength. The first wavelength, the second wavelength, and the third wavelength correspond to the activation wavelength band of the first initiator, the activation wavelength band of the second initiator, and the activation wavelength band of the third initiator, respectively.

[0261] Reference Fig.36E , the second release film 520 is attached on the cured composition 495. The second release film 520 may be disposed on the uncured composition 490, and then curing may be performed thereon.

[0262] Although certain embodiments and implementations have been described herein, other embodiments and variations will be apparent from this description. Accordingly, it will be apparent to those skilled in the art that the inventive concept is not limited to these embodiments, but to the broader scope of the appended claims and various apparent variations and equivalent arrangements.

Claims

1. A display device, comprising: Display panel; a covering member disposed on the display panel; as well as an adhesive layer disposed between the display panel and the cover member, wherein the adhesive layer has a first surface facing the cover member and a second surface facing the display panel, and in a first direction from the first surface toward the second surface, the adhesive layer includes a first region and a second region arranged at positions different from each other, and The modulus of the first region is different from the modulus of the second region, the bending stiffness of the first region is greater than or equal to 30 N·cm and less than or equal to 50 N·cm, and the bending stiffness of the second region is greater than or equal to 15 N·cm and less than or equal to 30 N·cm.

2. The display device according to claim 1, wherein: The adhesive layer has a modulus that is continuous between the first surface and the second surface.

3. The display device according to claim 1, wherein: The modulus of the first region is greater than or equal to 100 KPa and less than or equal to 1000 KPa, and the modulus of the second region is 100 KPa or less.

4. The display device according to claim 1, wherein: A difference between the modulus of the first region and the modulus of the second region is 100 KPa or more.

5. The display device according to claim 1, wherein: The adhesive layer has the modulus gradually decreasing along the first direction.

6. The display device according to claim 1, wherein: The adhesive layer has the modulus gradually increasing along the first direction.

7. The display device according to claim 1, wherein: The adhesive layer further includes a third region disposed between the first region and the second region, and each of the modulus of the first region and the modulus of the second region is higher than a modulus of the third region.

8. The display device according to claim 1, wherein: The adhesive layer further includes a third region disposed between the first region and the second region, and each of the modulus of the first region and the modulus of the second region is lower than a modulus of the third region.

9. A display device, comprising: Display panel; a covering member disposed on the display panel; as well as an adhesive layer disposed between the display panel and the cover member, wherein the adhesive layer comprises a plurality of non-folding regions and a folding region arranged between the plurality of non-folding regions, and Among them, the modulus of the folding area is greater than the modulus of the non-folding area, the bending stiffness of the folding area is greater than or equal to 30N·cm and less than or equal to 50N·cm, and the bending stiffness of the non-folding area is greater than or equal to 15N·cm and less than or equal to 30N·cm.

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