Flexible display device

Abstract

The present disclosure relates to a flexible display apparatus. The flexible display apparatus includes a display panel including a bendable area and an unbendable area adjacent to the bendable area in one direction, a window facing the display panel, and an adhesive layer between the display panel and the window. The adhesive layer includes a bendable portion corresponding to the bendable area and having a varying thickness along the one direction to define a pleat shape of the bendable portion, and an unbendable portion corresponding to the unbendable area and having a constant thickness along the one direction.

Description

TECHNICAL FIELD

[0001] Embodiments relate to a display apparatus. More particularly, embodiments relate to a bendable flexible display apparatus and a method of providing the same. BACKGROUND

[0002] A flexible display apparatus that can be formed into various shapes has been developed. Unlike a flat panel display, a flexible display apparatus can be foldable, bendable, or rollable like paper. A flexible display apparatus is easy to carry and can improve user convenience.

[0003] A flexible display apparatus can include a display panel that displays an image and a window disposed on the display panel to protect the display panel. An image displayed by the display panel can be provided to the outside of the display apparatus through the window. SUMMARY

[0004] Embodiments provide a flexible display apparatus in which a wrinkle is not visually recognized and a method of providing the same.

[0005] One or more embodiments of a flexible display apparatus include a display panel including a bendable area and an unbendable area adjacent to the bendable area in one direction, a window on the display panel, and an adhesive layer between the display panel and the window. The adhesive layer includes a bendable portion overlapping the bendable area and an unbendable portion overlapping the unbendable area. A thickness of the bendable portion varies along the one direction. A thickness of the unbendable portion is constant along the one direction.

[0006] In an embodiment, the bendable portion can have a maximum thickness between a bending axis and a point spaced apart from the bending axis by 1 / 4*π*R in the one direction, where R is a radius of curvature of the bendable area of the display panel.

[0007] In an embodiment, the maximum thickness of the bendable portion can be greater than the thickness of the unbendable portion.

[0008] In an embodiment, a value obtained by subtracting the thickness of the unbendable portion from the maximum thickness of the bendable portion can be about 5 micrometers (μm) to about 40 μm.

[0009] In an embodiment, the bendable portion can have a maximum thickness at a bending axis.

[0010] In an embodiment, the bendable portion can have a minimum thickness between a point spaced apart from the bending axis by 1 / 4*π*R in the one direction and a point spaced apart from the bending axis by 3 / 4*π*R in the one direction, where R is a radius of curvature of the bendable area of the display panel.

[0011] In an embodiment, the minimum thickness of the bendable portion can be less than a thickness of the non-bendable portion.

[0012] In an embodiment, a value obtained by subtracting the minimum thickness of the bendable portion from the thickness of the non-bendable portion can be about 5 μm to about 40 μm.

[0013] In an embodiment, the bendable portion can have the minimum thickness at a point spaced apart from the bending axis by 2 / 4*π*R along the one direction.

[0014] In an embodiment, the adhesive layer can include a first surface facing the display panel and a second surface facing the window. The second surface can be flat.

[0015] In an embodiment, the first surface can be wrinkled.

[0016] In an embodiment, the window can include glass.

[0017] In an embodiment, the display panel can include a plastic substrate.

[0018] In an embodiment, the flexible display apparatus can further include a polarizing layer between the display panel and the adhesive layer.

[0019] A method of providing a flexible display apparatus includes wrinkling a bendable area of a display panel; providing an adhesive layer on the display panel, the adhesive layer including a first surface facing the wrinkled display panel and a second surface opposite the first surface and flat; and providing a window on the display panel and between the display panel and the adhesive layer.

[0020] In an embodiment, wrinkling the bendable area of the display panel can include providing a table having an upper surface that is wrinkled; providing the display panel on the upper surface of the table, the bendable area being flat in the display panel; and providing pressure in a direction from the display panel to the table to wrinkle the bendable area of the display panel.

[0021] In an embodiment, providing the adhesive layer can include applying a liquid adhesive on the display panel.

[0022] In an embodiment, providing the adhesive layer can include attaching a solid adhesive film on the display panel.

[0023] A method of providing a flexible display apparatus includes wrinkling a bendable area of a window; providing an adhesive layer on the window, the adhesive layer including a first surface facing the wrinkled window and a second surface opposite the first surface and flat; providing a display panel on the window and between the window and the adhesive layer; and bending the bendable area of the window with the adhesive layer and the display panel and then straightening.

[0024] In an embodiment, the first surface can be flat and the second surface can be wrinkled after the bendable area of the window is bent and then straightened.

[0025] In the flexible display apparatus, the thickness of the bendable portion of the adhesive layer between the display panel and the window can vary in a direction along the window, so that the formation of wrinkles in the window can be reduced or effectively prevented. Accordingly, the wrinkles of the flexible display apparatus can be alleviated or effectively prevented from being recognized from the outside of the flexible display apparatus. BRIEF DESCRIPTION OF DRAWINGS

[0026] The embodiments will become more fully understood from the detailed description given herein below and the accompanying drawings, wherein:

[0027] Figure 1 and Figure 2 is a cross-sectional view illustrating an embodiment of a flexible display apparatus.

[0028] Figure 3 is an enlarged cross-sectional view illustrating an embodiment of a region X in Figure 1

[0029] Figure 4 is an enlarged cross-sectional view illustrating an embodiment of a display panel.

[0030] Figure 5 and Figure 6 is a perspective view illustrating an embodiment of a foldable display apparatus.

[0031] Figure 7 , Figure 8 , Figure 9 and Figure 10 is a cross-sectional view illustrating an embodiment of a method of providing a flexible display apparatus.

[0032] Figure 11 , Figure 12 , Figure 13 , Figure 14 and Figure 15 is a cross-sectional view illustrating an embodiment of a method of providing a flexible display apparatus. DETAILED DESCRIPTION

[0033] The present application will now be described more fully hereinafter with reference to the accompanying drawings, in which various embodiments are shown. The present application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the application to those skilled in the art. Like reference numerals refer to like elements throughout.

[0034] ​It will be understood that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements can be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

[0035] It will be understood that, although the terms "first", "second", "third", etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, "a first element", "a first component", "a first region", "a first layer" or "a first portion" discussed below could be termed a second element, a second component, a second region, a second layer or a second portion without departing from the teachings herein.

[0036] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, "a", "an", and "the" are intended to mean "one or more" unless otherwise indicated by the context. For example, the term "element" is intended to mean at least one element, unless the context clearly indicates otherwise. "At least one" should not be construed as limiting "one" or "one". "Or" means "and / or". As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will also be understood that the terms "comprises" and / or "comprising", or "includes" and / or "including" when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and / or groups thereof.

[0037] Furthermore, relative terms such as "lower" or "bottom" and "upper" or "top" can be used herein to describe one element's relationship to another element as the device is oriented in the drawing. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the drawings. For example, if the device in one of the drawings is turned over, elements described as being on the "lower" side of other elements would then be oriented on the "upper" sides thereof. The term "lower", can, therefore, encompass both an orientation of "lower" and "upper", depending on the particular orientation of the figure. Similarly, if the device in one of the drawings is turned over, elements described as "below" or "beneath" other elements would then be oriented "above" the other elements. The terms "below" or "beneath" can, therefore, encompass both an orientation of above and below. The device can be oriented in any direction and the relative terms can be interpreted accordingly.

[0038] As used herein, "about" or "approximately" can include the recited value and the average value within an acceptable range of deviation of the particular value as determined by one of ordinary skill in the art in view of the measurement discussed and the error associated with the measurement of the particular quantity (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations, or within ± 30%, ± 20%, ± 10%, or ± 5% of the recited value.

[0039] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0040] Embodiments are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and / or tolerances, are to be expected. Thus, embodiments described herein are not to be construed as being limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat can often have rough and / or nonlinear features. Moreover, sharp angles that are illustrated can be rounded. Thus, the regions illustrated in the figures are schematic

[0041] When the flexible display device 10 (refer to Figure 1 ) is bent and straightened many times, wrinkles can occur in the flexible display device 10. In particular, when the window 200 (refer to Figure 1When a wrinkle occurs in the flexible display apparatus 10, the wrinkle can be visually recognized from the outside of the flexible display apparatus 10. Accordingly, the display quality of the flexible display apparatus 10 can be deteriorated.

[0042] Hereinafter, embodiments of a flexible display apparatus and a method of providing a flexible display apparatus will be described in detail with reference to the accompanying drawings.

[0043] Figure 1 and Figure 2 are cross-sectional views illustrating embodiments of the flexible display apparatus 10. Figure 1 The flat or straightened flexible display apparatus 10 is illustrated, and Figure 2 The curved flexible display apparatus 10 is illustrated.

[0044] Referring to Figure 1 and Figure 2 , the flexible display apparatus 10 can include a display panel 100, a window 200, an adhesive layer 300, a polarizing layer 400, and a functional layer 500.

[0045] The display panel 100 can generate and / or display an image. The display panel 100 can include a plurality of pixels. Each of the pixels can generate and / or emit light for displaying the image.

[0046] The display panel 100 can include a bendable area BA and a plurality of non-bendable areas including non-bendable areas NBA1 and NBA2. The bendable area BA can be a planar area at which the display panel 100 is bendable, and the non-bendable areas NBA1 and NBA2 can be planar areas at which the display panel 100 is non-bendable and / or remains flat even when the display panel 100 is bent at the bendable area BA. The respective components and layers of the flexible display apparatus 10 can include bendable areas BA and non-bendable areas corresponding to the bendable area BA and the non-bendable areas described above with respect to the display panel 100.

[0047] The non-bendable areas NBA1 and NBA2 can include a first non-bendable area NBA1 and a second non-bendable area NBA2. The first non-bendable area NBA1 can be adjacent to the bendable area BA in a first direction DR1. The second non-bendable area NBA2 can be adjacent to the bendable area BA in a second direction DR2 opposite the first direction DR1. In other words, the bendable area BA can be positioned between the first non-bendable area NBA1 and the second non-bendable area NBA2 along the first direction DR1 (or along the second direction DR2). The straightened flexible display apparatus 10 can be disposed in a third direction (e.g., into the plane of the drawing) that intersects each of the first direction DR1 and the second direction DR2.Figure 1 a plane defined by the view) of the display panel 100.

[0048] The display panel 100 can include a layer having or formed of a polymer material. Accordingly, the display panel 100 can have a flexible characteristic. In an embodiment, the display panel 100 can include a plastic substrate.

[0049] The window 200 can be disposed on the display panel 100. The window 200 can transmit an image displayed from the display panel 100. The window 200 can protect the display panel 100 from the outside of the flexible display apparatus 10. The window 200 can provide an outer surface (or a front surface) of the flexible display apparatus 10.

[0050] In an embodiment, the window 200 can include glass. The window 200 can be formed of very thin glass, and thus, the window 200 can have a flexible characteristic.

[0051] The adhesive layer 300 can be disposed between the display panel 100 and the window 200 along a thickness direction of the flexible display apparatus 10. The adhesive layer 300 can couple the window 200 to the display panel 100.

[0052] The adhesive layer 300 can include a transparent adhesive material having a relatively high light transmittance. In an embodiment, the adhesive layer 300 can include an optical clear adhesive (OCA), an optical clear resin (OCR), a pressure sensitive adhesive (PSA), or the like.

[0053] The adhesive layer 300 can include a bendable portion BP and non-bendable portions NBP1 and NBP2. The bendable portion BP can be a portion of the adhesive layer 300 that is bendable, and the non-bendable portions NBP1 and NBP2 can be portions of the adhesive layer 300 at which the adhesive layer 300 is not bendable and / or which remain flat even when the adhesive layer 300 is bent at the bendable portion BP.

[0054] The bendable portion BP can overlap or correspond to the bendable area BA of the display panel 100. The non-bendable portions NBP1 and NBP2 can overlap or correspond to the non-bendable areas NBA1 and NBA2 of the display panel 100, respectively. The non-bendable portions NBP1 and NBP2 can include a first non-bendable portion NBP1 and a second non-bendable portion NBP2. The first non-bendable portion NBP1 can overlap or correspond to the first non-bendable area NBA1 of the display panel 100, and the second non-bendable portion NBP2 can overlap or correspond to the second non-bendable area NBA2 of the display panel 100. In other words, the bendable portion BP can be positioned between the first non-bendable portion NBP1 and the second non-bendable portion NBP2 in a direction along the display panel 100.

[0055] The polarization layer 400 can be disposed between the display panel 100 and the adhesive layer 300 along a thickness direction of the flexible display apparatus 10. The polarization layer 400 can reduce reflection of external light incident on the display panel 100 from outside of the flexible display apparatus 10 and through the window 200. In an embodiment, for example, when external light passes through the polarization layer 400 and is reflected from below the polarization layer 400 (e.g., at the display panel 100) and then passes through the polarization layer 400 again, the polarization layer 400 can change a phase of the external light. Thus, since the phase of the reflected light is different from that of the incident light entering the polarization layer 400, extinction interference can occur and reflection of the external light can be reduced, thereby improving visibility of a display image of the flexible display apparatus 10.

[0056] The polarization layer 400 can include a polymer material. Thus, the polarization layer 400 can have a flexible characteristic.

[0057] The functional layer 500 can be disposed below the display panel 100. The functional layer 500 faces the polarization layer 400, and the display panel 100 is between the functional layer 500 and the polarization layer 400. The functional layer 500 can include a layer that provides various functions for the display panel 100. In an embodiment, the functional layer 500 can include at least one of a light blocking layer, a buffer layer, and a heat dissipation layer. The light blocking layer can block light incident to the display panel 100. The buffer layer can absorb a physical impact applied to the display panel 100. The heat dissipation layer can emit heat generated from the display panel 100.

[0058] The functional layer 500 can include a layer having or formed of a polymer material. Thus, the functional layer 500 can have a flexible characteristic.

[0059] Within the flexible display apparatus 10, the window 200, the adhesive layer 300, the polarization layer 400, the display panel 100, and the functional layer 500 can be in order, and each of them can have a flexible characteristic. That is, one or more among the window 200, the adhesive layer 300, the polarization layer 400, the display panel 100, and the functional layer 500 can be bendable with another among the window 200, the adhesive layer 300, the polarization layer 400, the display panel 100, and the functional layer 500.

[0060] The flexible display apparatus 10 can be stretched out as shown in Figure 1 or can be bent as shown in Figure 2The flexible display apparatus 10 can be bent with respect to the bending axis BX. In an embodiment, the flexible display apparatus 10 can be bent such that portions of the window 200 can face each other. For example, in an embodiment, the flexible display apparatus 10 can be bent such that a first portion of the window 200 corresponding to the first non-bendable area NBA1 of the display panel 100 and a second portion of the window 200 corresponding to the second non-bendable area NBA2 of the display panel 100 can face each other.

[0061] The flexible display apparatus 10 can be bent to define a curvature of the flexible display apparatus 10. The bendable area BA of the display panel 100 of the bent flexible display apparatus 10 can have a radius of curvature R.

[0062] Figure 3 is an enlarged cross-sectional view illustrating a region X in Figure 1

[0063] Referring to Figure 1 and Figure 3 When the flexible display apparatus 10 is bent and straightened multiple times, each of the display panel 100, the polarizing layer 400, and the functional layer 500 can be deformed compared to being completely flat. For example, in an embodiment, when the flexible display apparatus 10 is bent and straightened multiple times, each of the bendable area BA of the display panel 100, the portion of the polarizing layer 400 overlapping the bendable area BA, and the portion of the functional layer 500 overlapping the bendable area BA of the straightened flexible display apparatus 10 can have a folded shape or an uneven shape in a cross-sectional view. As described above, each of the display panel 100, the polarizing layer 400, and the functional layer 500 can include a polymer material. Since the polymer material has a molecular structure in the form of a chain, plastic deformation can occur in each of the display panel 100, the polarizing layer 400, and the functional layer 500 (e.g., at the bendable area BA) when the flexible display apparatus 10 is bent and straightened multiple times.

[0064] As described above, the window 200 can include glass. Since the glass has a crystal arrangement structure, plastic deformation can not occur in the window 200 or can be less than plastic deformation of the display panel 100, the polarizing layer 400, and / or the functional layer 500 when the flexible display apparatus 10 is bent and straightened multiple times. However, when the window 200 is bonded to the display panel 100, the polarizing layer 400, and the functional layer 500 such as through the adhesive layer 300, stress generated by the deformed display panel 100, the polarizing layer 400, and the functional layer 500 can be transmitted to the window 200 through the adhesive layer 300, and thus, the window 200 can be deformed by the stress.

[0065] ​To prevent the deformation of the window 200 described above, the thickness of the bendable portion BP of the adhesive layer 300 can vary along the first direction DR1 and / or the second direction DR2. The thickness of the bendable portion BP of the adhesive layer 300 can vary along the first direction DR1 and / or the second direction DR2 based on the deformation of each of the display panel 100, the polarizing layer 400, and the functional layer 500, so that the deformation of the window 200 can be reduced or effectively prevented. That is, even at the bendable area BA, the thickness of the varying bendable portion BP can set the window 200 to be flat or straightened.

[0066] The thickness of the non-bendable portions NBP1 and NBP2 of the adhesive layer 300 can be constant along the first direction DR1 and / or the second direction DR2. Although the flexible display apparatus 10 is bent and straightened multiple times, the thickness of the non-bendable portions NBP1 and NBP2 of the adhesive layer 300 can be constant along the first direction DR1 and / or the second direction DR2 since the non-bendable areas NBA1 and NBA2 of the display panel 100, the portions of the polarizing layer 400 overlapping the non-bendable areas NBA1 and NBA2, and the portions of the functional layer 500 overlapping the non-bendable areas NBA1 and NBA2 are not deformed. Accordingly, the non-bendable portions NBP1 and NBP2 can have a constant thickness TH1. Referring to Figure 3 At the first non-bendable portion NBP1 and the second non-bendable portion NBP2, the adhesive layer 300 can have the thickness TH1 along the entirety of the first non-bendable area NBA1 and the second non-bendable area NBA2 of the display panel 100.

[0067] The adhesive layer 300 can include a point A and a point A' (e.g., a first point) spaced apart from the bending axis BX by 1 / 4*π*R in the first direction DR1 and the second direction DR2, respectively, a point B and a point B' (e.g., a second point) spaced apart from the bending axis BX by 2 / 4*π*R in the first direction DR1 and the second direction DR2, respectively, and a point C and a point C' (e.g., a third point) spaced apart from the bending axis BX by 3 / 4*π*R in the first direction DR1 and the second direction DR2, respectively. The point A, the point B, and the point C or the point A', the point B', and the point C' can be sequentially from the bending axis BX.

[0068] In an embodiment, the bendable portion BP extending along the display panel 100 can have a maximum thickness TH2 between the bending axis BX and a corresponding point among the point A and the point A' spaced apart from the bending axis BX by 1 / 4*π*R in the first direction DR1 and the second direction DR2, respectively. Here, R can be a radius of curvature of the bendable area BA of the display panel 100 (R = 1 / 2*π*R). Figure 2In other words, the flexible portion BP of the adhesive layer 300 can have a maximum thickness TH2 between point A (e.g., the first point) spaced 1 / 4*π*R from the bending axis BX along the first direction DR1 and point A' (e.g., the first point) spaced 1 / 4*π*R from the bending axis BX along the second direction DR2 (e.g., from point A to point A').

[0069] In an implementation, the bendable portion BP may have a maximum thickness TH2 corresponding to the bending axis BX.

[0070] In an implementation, the maximum thickness TH2 of the bendable portion BP can be greater than the thickness TH1 of the inflexible portions NBP1 and NBP2.

[0071] In an embodiment, the value obtained by subtracting the thickness TH1 of the inflexible portions NBP1 and NBP2 from the maximum thickness TH2 of the flexible portion BP (e.g., the difference) can be from about 5 micrometers (μm) to about 40 μm. The value obtained by subtracting the thickness TH1 of the inflexible portions NBP1 and NBP2 from the maximum thickness TH2 of the flexible portion BP can be adjusted proportionally to the total thickness TH4 of the display panel 100, the polarizing layer 400, and the functional layer 500, and can be in the range of about 5 μm to about 40 μm. When the value obtained by subtracting the thickness TH1 of the inflexible portions NBP1 and NBP2 from the maximum thickness TH2 of the flexible portion BP is less than about 5 μm, the adhesive layer 300 may not be able to adequately compensate for the stress caused by the deformation of each of the display panel 100, the polarizing layer 400, and the functional layer 500. Furthermore, when the value obtained by subtracting the thickness TH1 of the inflexible portions NBP1 and NBP2 from the maximum thickness TH2 of the flexible portion BP is greater than about 40 μm, the radius of curvature of the flexible display device 10 may increase as the adhesive layer 300 thickens.

[0072] In an embodiment, the flexible portion BP may have a minimum thickness TH3 between points A and A', which are spaced 1 / 4*π*R apart from the bending axis BX along the first direction DR1 and the second direction DR2, and points C and C', which are spaced 3 / 4*π*R apart from the bending axis BX along the first direction DR1 and the second direction DR2, respectively. In other words, the flexible portion BP may have a minimum thickness TH3 between point A, which is spaced 1 / 4*π*R apart from the bending axis BX along the first direction DR1, and point C (e.g., the third point), or between point A', which is spaced 1 / 4*π*R apart from the bending axis BX along the second direction DR2, and point C' (e.g., the third point), which is spaced 3 / 4*π*R apart from the bending axis BX along the second direction DR2.

[0073] In an embodiment, the bendable portion BP can have a minimum thickness TH3 at a point B and a point B' spaced apart from the bend axis BX by 2 / 4*π*R in the first direction DR1 and the second direction DR2, respectively. In other words, the bendable portion BP can have a minimum thickness TH3 at the point B (e.g., the second point) spaced apart from the bend axis BX by 2 / 4*π*R along the first direction DR1 or at the point B' (e.g., the second point) spaced apart from the bend axis BX by 2 / 4*π*R along the second direction DR2.

[0074] In an embodiment, the minimum thickness TH3 of the bendable portion BP can be less than the thickness TH1 of the non-bendable portions NBP1 and NBP2.

[0075] In an embodiment, a value obtained by subtracting the minimum thickness TH3 of the bendable portion BP from the thickness TH1 of the non-bendable portions NBP1 and NBP2 can be about 5 µm to about 40 µm. The value obtained by subtracting the minimum thickness TH3 of the bendable portion BP from the thickness TH1 of the non-bendable portions NBP1 and NBP2 can be adjusted in a range of about 5 µm to about 40 µm in proportion to the total thickness TH4 of the thickness of the display panel 100, the thickness of the polarizing layer 400, and the thickness of the functional layer 500. When the value obtained by subtracting the minimum thickness TH3 of the bendable portion BP from the thickness TH1 of the non-bendable portions NBP1 and NBP2 is less than about 5 µm, the adhesive layer 300 can not sufficiently compensate for stress due to deformation of each of the display panel 100, the polarizing layer 400, and the functional layer 500. In addition, when the value obtained by subtracting the minimum thickness TH3 of the bendable portion BP from the thickness TH1 of the non-bendable portions NBP1 and NBP2 is greater than about 40 µm, the adhesive layer 300 can excessively compensate for stress due to deformation of the display panel 100, the polarizing layer 400, and the functional layer 500.

[0076] The adhesive layer 300 can include a first surface 310 facing the display panel 100 and a second surface 320 facing the window 200. The first surface 310 can be opposite the second surface 320. The first surface 310 of the adhesive layer 300 can be wrinkled (e.g., a plurality of wrinkles WRK can be formed at the first surface 310 of the adhesive layer 300), and the second surface 320 of the adhesive layer 300 can remain flat. The display panel 100, the polarizing layer 400, and the functional layer 500 can include recessed portions recessed away from the adhesive layer 300 and corresponding to the wrinkles WRK. Although the first surface 310 of the adhesive layer 300 is wrinkled, since the thickness of the bendable portion BP of the adhesive layer 300 varies corresponding to the wrinkles WRK along the first direction DR1 and / or the second direction DR2, the adhesive layer 300 can have a flat second surface 320 to define a flat surface. Accordingly, the window 200 closer to the second surface 320 than the first surface 310 can not be wrinkled, and the window 200 can maintain a flat shape.

[0077] Figure 4 is an enlarged cross-sectional view illustrating an embodiment of the display panel 100. Figure 4 One pixel of the display panel 100 in Figure 1 may be illustrated.

[0078] Referring to Figure 4 , the display panel 100 can include a substrate 110, a transistor 120, a light emitting element 140, and a thin film encapsulation layer 150.

[0079] The substrate 110 can be a transparent or non-transparent insulating substrate. In an embodiment, the substrate 110 can include plastic such as polyimide, polycarbonate, polyethylene terephthalate, polyacrylate, or the like.

[0080] An active pattern 121 of the transistor 120 can be disposed on the substrate 110. In an embodiment, the active pattern 121 can include amorphous silicon, polysilicon, or the like. In an embodiment, the active pattern 121 can include an oxide semiconductor.

[0081] A gate insulating layer 131 can be disposed on the substrate 110 and can cover the active pattern 121. The gate insulating layer 131 can include an inorganic insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or the like.

[0082] A gate electrode 122 of the transistor 120 can be disposed on the gate insulating layer 131 and can overlap the active pattern 121. The gate electrode 122 can include a conductive material such as copper (Cu), molybdenum (Mo), titanium (Ti), aluminum (Al), or the like.

[0083] An insulating interlayer 132 can be provided on the gate insulating layer 131, and can cover the gate electrode 122. The insulating interlayer 132 can include an inorganic insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or the like.

[0084] The source electrode 123 and the drain electrode 124 of the transistor 120 can be provided on the insulating interlayer 132, and can be connected to the active pattern 121. The source electrode 123 and the drain electrode 124 can include a conductive material such as copper (Cu), molybdenum (Mo), titanium (Ti), aluminum (Al), or the like. The active pattern 121, the gate electrode 122, the source electrode 123, and the drain electrode 124 can together form the transistor 120.

[0085] A planarization layer 133 can be provided on the insulating interlayer 132, and can cover the source electrode 123 and the drain electrode 124. The planarization layer 133 can include an inorganic insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or the like, and / or an organic insulating material such as an acrylic resin, an epoxy resin, a phenol resin, a polyamide resin, a polyimide resin, an unsaturated polyester resin, a phenylene resin, a polyphenylene sulfide resin, benzocyclobutene, or the like.

[0086] A pixel electrode 141 of the light-emitting element 140 can be provided on the planarization layer 133, and can be connected to the drain electrode 124. The pixel electrode 141 can include a transparent conductive layer including indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In2O3), or the like, and a reflective conductive layer including silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), lead (Pb), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), or the like. In an embodiment, the pixel electrode 141 can have a stacked structure of ITO, Ag, and ITO. In such an embodiment, the pixel electrode 141 can be a reflective electrode.

[0087] A pixel-defining layer 134 can be provided on the planarization layer 133, and can cover at least a portion of the pixel electrode 141. In an embodiment, the pixel-defining layer 134 can cover a peripheral portion or an edge of the pixel electrode 141, and can define a pixel opening that exposes a central portion of the pixel electrode 141 outside the pixel-defining layer 134. The pixel-defining layer 134 can include an inorganic insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or the like, and / or an organic insulating material such as an acrylic resin, an epoxy resin, a phenol resin, a polyamide resin, a polyimide resin, an unsaturated polyester resin, a phenylene resin, a polyphenylene sulfide resin, benzocyclobutene, or the like.

[0088] The emission layer 142 of the light emitting element 140 can be disposed on the pixel electrode 141 exposed by the pixel opening and on the pixel definition layer 134. Holes provided from the pixel electrode 141 and electrons provided from the counter electrode 143 recombine in the emission layer 142 to form excitons, and the excitons change from an excited state to a ground state so that the emission layer 142 can emit light.

[0089] The counter electrode 143 can be disposed on the emission layer 142. The counter electrode 143 can include a transparent conductive layer including lithium (Li), calcium (Ca), aluminum (Al), magnesium (Mg), silver (Ag), platinum (Pt), lead (Pb), nickel (Ni), gold (Au), neodymium (Nd), iridium (Ir), chromium (Cr), barium (Ba), or the like. The counter electrode 143 can be a transmissive electrode. The pixel electrode 141, the emission layer 142, and the counter electrode 143 can together form the light emitting element 140.

[0090] The thin film encapsulation layer 150 can be disposed on the counter electrode 143. The thin film encapsulation layer 150 can reduce or effectively prevent impurities and moisture from penetrating into the light emitting element 140 from the outside of the thin film encapsulation layer 150. The thin film encapsulation layer 150 can include at least one inorganic encapsulation layer and at least one organic encapsulation layer. In an embodiment, the thin film encapsulation layer 150 can include a first inorganic encapsulation layer 151, a second inorganic encapsulation layer 153 disposed on the first inorganic encapsulation layer 151, and an organic encapsulation layer 152 disposed between the first inorganic encapsulation layer 151 and the second inorganic encapsulation layer 153.

[0091] Figure 5 and Figure 6 is a perspective view showing the foldable display apparatus 1000.

[0092] Referring to Figure 5 and Figure 6 , the foldable display apparatus 1000 can be foldable and / or unfoldable about the folding axis FX. Figure 1 and Figure 2 The flexible display apparatus 10 shown in Figure 5 and Figure 6 can be applied to the foldable display apparatus 1000. In this case, the bending axis BX of the flexible display apparatus 10 can correspond to the folding axis FX of the foldable display apparatus 1000. However, the present application is not limited thereto, and the flexible display apparatus 10 shown in Figure 1 and Figure 2 can also be applied to a rollable display apparatus or a slideable display apparatus.

[0093] Figure 7 , Figure 8 , Figure 9 and Figure 10This is a cross-sectional view illustrating an embodiment of a method for providing a flexible display device 10.

[0094] refer to Figure 7 and Figure 8 The first flexible region BA1 of the display panel 100 can be made from its original flat shape. Figure 7 Pre-pleats Figure 8 Multiple first folds WRK1 can be set, and multiple first folds WRK1 can be in the first flexible area BA1 of the display panel 100.

[0095] like Figure 7 As shown, a stage 600 can be provided. The upper surface 610 of the stage 600 can be folded in a region corresponding to the first flexible region BA1 of the display panel 100. In other words, a curved surface defining the stage fold 620 can be provided or formed on the upper surface 610 of the stage 600. A plurality of suction holes 630 are provided, and the stage 600 can include a plurality of suction holes 630. Each of the suction holes 630 can completely penetrate the thickness of the stage 600. Each of the suction holes 630 can extend from the lower surface of the stage 600 to the upper surface 610 of the stage 600 opposite to the lower surface of the stage 600.

[0096] refer to Figure 7 A preliminary display panel 100 can be disposed on the upper surface 610 of the stage 600. In the preliminary display panel 100, the first flexible region BA1 is initially flat. A polarizing layer 400 can be attached above the display panel 100, and a functional layer 500 can be attached below the display panel 100. The portions of the polarizing layer 400 and the functional layer 500 that overlap with the first flexible region BA1 can initially be flat.

[0097] like Figure 8 As shown, it can be in the direction from display panel 100 to stage 600 (by... Figure 8 Pressure is applied to the first flexible region BA1 of the display panel 100 (indicated by the downward arrow in the diagram) to cause wrinkles in the corresponding regions of the polarizing layer 400 and the functional layer 500. Therefore, a first wrinkle WRK1 can be provided or formed in the first flexible region BA1 of the display panel 100. The first wrinkle WRK1 provided or formed in the first flexible region BA1 of the display panel 100 can correspond to a stage wrinkle 620 defined at the upper surface 610 of the stage 600. Wrinkles corresponding to the stage wrinkle 620 defined at the upper surface 610 of the stage 600 can be provided or formed in each of the corresponding flexible portions of the polarizing layer 400 and the functional layer 500 that overlap with the first flexible region BA1.

[0098] refer toFigure 7 and Figure 8 The method of providing the flexible display apparatus 10 can include providing the preliminary display panel 100 that is wrinkled at the first bendable area BA1 thereof to provide the wrinkled display panel 100 including the first bendable area BA1 having the wrinkles with the wrinkled shape. The method can further include providing the stage 600 having the upper surface 610 that is wrinkled and has a shape corresponding to the wrinkled shape of the wrinkled first bendable area BA1 of the wrinkled display panel 100, providing the preliminary display panel 100 including the flat first bendable area BA1 on the wrinkled upper surface 610 of the stage 600, and providing a pressure in a direction from the preliminary display panel 100 to the stage 600 to wrinkle the first bendable area BA1 of the preliminary display panel 100.

[0099] In an embodiment, the pressure can be applied to each of the functional layer 500, the display panel 100, and the polarizing layer 400 through the suction hole 630 to deform each of the functional layer 500, the display panel 100, and the polarizing layer 400. The functional layer 500, the display panel 100, and the polarizing layer 400 can be deformed together (e.g., simultaneously) by the pressure applied through the suction hole 630, without being limited thereto. Referring to Figure 8 Each of the functional layer 500, the display panel 100, and the polarizing layer 400 can be deformed along the contour of the upper surface 610 of the stage 600 at which the stage wrinkles 620 are disposed or formed. That is, the wrinkles of the functional layer 500, the display panel 100, and the polarizing layer 400 can have shapes corresponding to the shape of the stage wrinkles 620.

[0100] Referring to Figure 9 The adhesive layer 300 can be disposed or formed on the display panel 100. The adhesive layer 300 can include a first surface 310 that is wrinkled and faces the display panel 100, and a second surface 320 that is flat and opposite to the first surface 310. That is, the display panel 100 that is wrinkled due to the first wrinkles WRK1 disposes the first surface 310 of the adhesive layer 300 as a wrinkled surface, and disposes the second surface 320 as a flat surface. The second wrinkles WRK2 of the adhesive layer 300 can be disposed or formed at the first surface 310. The shape or contour of the second wrinkles WRK2 of the adhesive layer 300 can correspond to the shape or contour of the wrinkles of the functional layer 500, the display panel 100, and the polarizing layer 400. The interface between the adhesive layer 300 and the window 200 can be flat, and the interface between the adhesive layer 300 and the stack structure including the display panel 100 can be wrinkled. Referring to Figure 9The method of providing the flexible display apparatus 10 can further include providing the adhesive layer 300 on the wrinkled display panel 100, the adhesive layer 300 including a bendable portion BP corresponding to the wrinkled first bendable area BA1 of the wrinkled display panel 100, the bendable portion BP including a first surface 310 facing the wrinkled display panel 100 and having a wrinkled shape corresponding to a wrinkled shape of the wrinkled first bendable area BA1 of the wrinkled display panel 100, and a second surface 320 opposite the first surface 310 and being flat.

[0101] In an embodiment, the adhesive layer 300 can be provided or formed by applying a liquid adhesive on the display panel 100. The adhesive can have a surface tension. That is, providing the adhesive layer 300 can include providing the liquid adhesive on the wrinkled display panel 100. Accordingly, although the adhesive is applied on the upper surface of the polarizing layer 400 on which the wrinkles are provided or formed, the adhesive layer 300 including the flat second surface 320 can be provided or formed, such as due to the surface tension of the adhesive layer material.

[0102] In another embodiment, the adhesive layer 300 can be formed by attaching a solid adhesive film on the display panel 100. That is, providing the adhesive layer 300 can include providing the solid adhesive film attached to the wrinkled display panel 100. Before being attached to the display panel 100, the adhesive film can be formed to include a wrinkled surface at which wrinkles corresponding to the first wrinkles WRK1 formed in the display panel 100 are formed, and another flat surface. Accordingly, the adhesive layer 300 including the flat second surface 320 can be formed on the wrinkled upper surface of the polarizing layer 400.

[0103] Referring to Figure 10 The window 200 can be provided or formed to face the display panel 100, and the adhesive layer 300 is interposed between the window 200 and the display panel 100. The window 200 can be provided or formed on the flat second surface 320 of the adhesive layer 300, and thus the window 200 can have a flat shape even in the bendable area BA. Referring to Figure 10 The method of providing the flexible display apparatus 10 can further include providing the window 200 to face the wrinkled display panel 100, and the adhesive layer 300 between the window 200 and the display panel 100, the window 200 having a flat shape corresponding to the flat second surface 320 of the adhesive layer 300.

[0104] Referring again to Figure 3 The flat flexible display apparatus 10 includes the display panel 100 having the first wrinkles WRK1 in the bendable area BA, and the adhesive layer 300 having the second wrinkles WRK2 corresponding to the first wrinkles WRK1.

[0105] Figure 11、 Figure 12 、 Figure 13 、 Figure 14 and Figure 15 are cross-sectional views illustrating embodiments of a method of providing a flexible display apparatus 10. Elements in the method of providing a flexible display apparatus 10 with reference to Figure 11 to Figure 15 are substantially the same as or similar to elements in the method of providing a flexible display apparatus 10 with reference to Figure 7 to Figure 10 , and thus a description thereof will not be repeated.

[0106] With reference to Figure 11 and Figure 12 , a second bendable area BA2 of a window 200 can be pre-corrugated from an original flat shape ( Figure 11 ). A first corrugation WRK1 can be disposed or formed in the second bendable area BA2 of the window 200.

[0107] As shown in Figure 11 , a preliminary form of the window 200 in which the second bendable area BA2 is initially flat can be disposed on an upper surface 610 of a table 600.

[0108] As shown in Figure 12 , a pressure can be applied in a direction from the window 200 to the table 600 (indicated by a downward arrow in Figure 12 ) to corrugate the second bendable area BA2 of the window 200. Thus, the first corrugation WRK1 can be disposed or formed in the second bendable area BA2 of the window 200. The first corrugation WRK1 disposed or formed in the second bendable area BA2 of the window 200 can correspond to a table corrugation 620 defined at the upper surface 610 of the table 600. With reference to Figure 12 , the method of providing a flexible display apparatus 10 can include providing a preliminary window 200 corrugated at a second bendable area BA2 thereof to provide a corrugated window 200 including a second bendable area BA2 having a corrugation of a corrugated shape.

[0109] With reference to Figure 13 , an adhesive layer 300 can be disposed or formed on the window 200 having the first corrugation WRK1. The adhesive layer 300 can include a first surface 310 facing the corrugation of the window 200 and a second surface 320 flat and opposite to the first surface 310. A second corrugation WRK2 can be disposed or formed at the first surface 310. The first surface 310 can define a corrugated surface of the adhesive layer 300. A shape or profile of the second corrugation WRK2 of the adhesive layer 300 can correspond to a shape or profile of the first corrugation WRK1 of the window 200. With reference to Figure 13The method of providing the flexible display apparatus 10 can further include disposing the adhesive layer 300 on the wrinkled window 200, the adhesive layer 300 including the bendable portion BP corresponding to the wrinkled second bendable area BA2 of the wrinkled window 200, the adhesive layer 300 including the preliminary first surface 310 facing the wrinkled window 200 and having a preliminary first surface 310 corresponding to the wrinkled shape of the wrinkled second bendable area BA2 of the wrinkled window 200, and the preliminary second surface 320 opposite to the preliminary first surface 310 and being flat.

[0110] Referring to Figure 14 The display panel 100 can be disposed or formed on the window 200, and the adhesive layer 300 is interposed between the display panel 100 and the window 200. The display panel 100 can be disposed or formed on the flat second surface 320 of the adhesive layer 300, and thus, the display panel 100 can have a flat shape. The polarizing layer 400 can be disposed or formed between the display panel 100 and the adhesive layer 300, and the functional layer 500 can be disposed or formed on the display panel 100. Each of the polarizing layer 400 disposed between the flat second surface 320 of the adhesive layer 300 and the flat display panel 100 and the functional layer 500 disposed or formed on the flat display panel 100 can also have a flat shape. Referring to Figure 14 The method of providing the flexible display apparatus 10 can further include disposing the display panel 100 to face the wrinkled window 200, and the adhesive layer 300 having the preliminary first surface 310 between the wrinkled window 200 and the display panel 100.

[0111] Referring to Figure 15 The second bendable area BA2 of the window 200 can be bent and then straightened, the second bendable area BA2 of the window 200 having the layered structure including the adhesive layer 300, the polarizing layer 400, the display panel 100, and the functional layer 500 thereon. In this case, each of the portion of the display panel 100 overlapping the second bendable area BA2, the portion of the adhesive layer 300 overlapping the second bendable area BA2, the portion of the polarizing layer 400 overlapping the second bendable area BA2, and the portion of the functional layer 500 overlapping the second bendable area BA2 can be bent at the second bendable area BA2 of the window 200 together with the window 200 and then straightened. Referring to Figure 15The method of providing the flexible display apparatus 10 can further include providing the wrinkled window 200, the display panel 100 facing the wrinkled window 200, and each of the adhesive layers 300 bent and straightened together with each other between the wrinkled window 200 and the display panel 100. The providing the wrinkled window 200, the display panel 100 facing the wrinkled window 200, and each of the adhesive layers 300 bent and straightened together with each other between the wrinkled window 200 and the display panel 100 includes flattening the preliminary first surface 310 and wrinkling the preliminary second surface 320 to have a wrinkled shape corresponding to a wrinkled shape of the wrinkled second bendable area BA2 of the wrinkled window 200.

[0112] When each of the portion of the display panel 100 overlapping the second bendable area BA2, the portion of the polarizing layer 400 overlapping the second bendable area BA2, and the portion of the functional layer 500 overlapping the second bendable area BA2 is bent and then straightened, plastic deformation can occur in each of the display panel 100, the polarizing layer 400, and the functional layer 500. Accordingly, the portion of the display panel 100 overlapping the second bendable area BA2, the portion of the polarizing layer 400 overlapping the second bendable area BA2, and the portion of the functional layer 500 overlapping the second bendable area BA2 can be pre-wrinkled. In this case, the third wrinkles WRK3 are provided in a plurality, the plurality of third wrinkles WRK3 can be provided or formed at the second surface 320 of the adhesive layer 300, and the first surface 310 of the adhesive layer 300 can remain flat. That is, the second surface 320 closest to the display panel 100 can define a wrinkled surface of the adhesive layer 300. Further, the window 200 can be deformed according to deformation of the first surface 310 of the adhesive layer 300, and thus, the window 200 can have a flat shape without wrinkles. That is, the bending and straightening of the pre-wrinkled adhesive layer 300 includes wrinkling of the second surface 320 of the adhesive layer 300, and flattening of the first surface 310 of the adhesive layer 300 together with the window 200, in addition to wrinkling of the functional layer 500, the display panel 100, and the polarizing layer 400.

[0113] One or more embodiments of the flexible display apparatus 10 can be applied to a display apparatus included in a computer, a notebook, a mobile phone, a smart phone, a smart pad, a personal media player (PMP), a personal digital assistant (PDA), an MP3 player, etc.

[0114] Although embodiments of the flexible display apparatus and the method of providing the flexible display apparatus have been described with reference to the accompanying drawings, the illustrated embodiments are examples, and modifications and changes can be made by those skilled in the related art without departing from the technical spirit described in the following claims.

Claims

1. A flexible display apparatus comprising: a display panel including a bendable area and an unbendable area, the display panel being bendable at the bendable area, the unbendable area being adjacent to the bendable area in one direction; a window facing the display panel and being bendable with the display panel; and an adhesive layer between the display panel and the window and being bendable with the display panel, the adhesive layer including: a bendable portion corresponding to the bendable area and having a varying thickness along the one direction to define a pleated shape of the bendable portion; an unbendable portion corresponding to the unbendable area and having a constant thickness along the one direction; a first surface facing the display panel; and a second surface opposite to the first surface and facing the window, wherein the second surface facing the window is flat at the bendable portion of the adhesive layer. 2.The flexible display apparatus of claim 1, wherein: the bendable area of the display panel includes a bending axis around which the display panel is bendable, the display panel bent around the bending axis has a radius of curvature at the bendable area, and the bendable portion of the adhesive layer includes: wherein R is the radius of curvature of the bendable area of the display panel. in the one direction spaced 1 / 4 π R of the point, and a maximum thickness between the points of R, is less than 1 / 4 π a maximum thickness between the points of R, is less than 1 / 4 The maximum thickness of the bendable portion is greater than the thickness of the unbendable portion within the adhesive layer. 3.The flexible display apparatus of claim 2, wherein, A difference between the thickness of the unbendable portion of the adhesive layer and the maximum thickness of the bendable portion of the adhesive layer is 5 to 40 micrometers.

4. The flexible display device of claim 3, wherein, The maximum thickness of the bendable portion corresponds to the bending axis of the display panel within the adhesive layer. 5.The flexible display apparatus of claim 2, wherein, 6.The flexible display apparatus of claim 1, wherein: the bendable area of the display panel includes a bending axis around which the display panel is bendable, the display panel bent around the bending axis has a radius of curvature at the bendable area, and the bendable portion of the adhesive layer includes: wherein R is the radius of curvature of the bendable area of the display panel. 1 / 4 π R of the first point, in the one direction spaced 3 / 4 π R the second point, and a minimum thickness between the first point of R and the second point of R spaced 3 / 4 of the way along the one direction from the bend axis π a minimum thickness between the first point of R and the second point of R spaced 3 / 4 of the way along the one direction from the bend axis π a minimum thickness between the first point of R and the second point of R spaced 3 / 4 of the way along the one direction from the bend axis The minimum thickness of the bendable portion is less than the thickness of the unbendable portion within the adhesive layer.

7. The flexible display device of claim 6, wherein, A difference between the minimum thickness of the bendable portion and the thickness of the unbendable portion is 5 to 40 micrometers.

8. The flexible display device of claim 7, wherein, Within the adhesive layer: 9.The flexible display apparatus of claim 6, wherein, the second surface facing the window is flat at the unbendable portion of the adhesive layer. The bendable portion further comprises a third point R spaced apart from the bend axis in the one direction by 2 / 4 π R, and the minimum thickness and spaced apart from the bend axis in the one direction by 2 / 4 π the third point of R corresponds. 10.The flexible display apparatus of claim 1, wherein, ​

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