Foldable display device

Abstract

The invention discloses a foldable display device comprising a display panel including a folding area and a non-folding area; and a light guide member disposed on the display panel and including the folding area and the non-folding area, in which the light guide member includes a plurality of first lens patterns disposed in the non-folding area, a first filling layer disposed in the non-folding area and disposed on the plurality of first lens patterns, and a second filling layer disposed in the non-folding area and disposed on the plurality of second lens patterns. And an intermediate layer disposed in the folding region, wherein a difference between a modulus of an upper surface of the intermediate layer and a modulus of a lower surface of the intermediate layer is smaller than a difference between a modulus of the plurality of first lens patterns and a modulus of the first filling layer.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Korean Patent Application No. 10-2023-0099854, filed on Jul. 31, 2023, which is incorporated herein by reference as if fully set forth herein. Technical Field

[0003] The present disclosure relates to a foldable display device in which internal light extraction efficiency is increased, reflectivity of external light is reduced, and stress generated during folding is alleviated. Background Art

[0004] As the information society develops, the demand for display devices is also developing in various forms. In response to this, various flat panel display devices such as liquid crystal displays (LCDs), organic light emitting displays (OLEDs), and micro LED displays have been developed in recent years.

[0005] In particular, foldable displays or rollable displays that utilize the advantages of bendable or foldable flexible display panels have attracted attention as the next generation technology in the field of display devices because they can provide large-screen displays while maintaining the convenience of portability. Flexible display devices can be applied to portable electronic devices such as mobile communication terminals, electronic notebooks, electronic books, PMPs (portable multimedia players), navigation, UMPCs (ultra-mobile PCs), mobile phones, smart phones, tablet computers, etc. They can also be applied to various fields such as televisions, monitors, and car dashboards.

[0006] A foldable display device is folded to have a small area when carried, and has an advantage of being able to use a wide display area by unfolding it when used. Meanwhile, since the foldable display device repeats the operation of folding and unfolding many times, it is more susceptible to damage than other display devices. There is a need for a structural improvement that does not cause damage even when used for a long time by alleviating the folding stress and / or bending stress caused by repeating such folding and unfolding operations. Summary of the invention

[0007] The present disclosure is made in view of the above-mentioned problems, and an object of the present disclosure is to provide a foldable display device including multiple lens patterns capable of minimizing or reducing the occurrence of rainbow mura and annular mura phenomena due to reflection of external light and capable of suppressing peeling in a folding area during folding due to modulus differences of the material.

[0008] According to one aspect of the present disclosure, the above and other purposes can be achieved by providing a foldable display device, which includes: a display panel including a folding area and a non-folding area; and a light guide member arranged on the display panel and including a folding area and a non-folding area, wherein the light guide member includes a plurality of first lens patterns arranged in the non-folding area, a first filling layer arranged in the non-folding area and arranged on the plurality of first lens patterns, and an intermediate layer arranged in the folding area, wherein the difference between the modulus of the upper surface of the intermediate layer and the modulus of the lower surface of the intermediate layer is smaller than the difference between the modulus of the plurality of first lens patterns and the modulus of the first filling layer.

[0009] In addition, the above and other purposes can be achieved by providing a foldable display device, which includes: a display panel including a folding area and a non-folding area; and a light guide member arranged on the display panel and including a folding area and a non-folding area, wherein the light guide member includes a plurality of first lens patterns arranged in the non-folding area, a first filling layer arranged in the non-folding area and arranged on the plurality of first lens patterns, and an intermediate layer arranged in the folding area, wherein the intermediate layer includes a continuous area having the same modulus from the upper surface of the light guide member to the lower surface of the light guide member. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other objects, features and other advantages of the present disclosure will be more clearly understood through the following detailed description in conjunction with the accompanying drawings, in which:

[0011] Figure 1 is a plan view of a foldable display device according to an embodiment of the present disclosure.

[0012] Figure 2 is a schematic cross-sectional view showing a foldable display device according to an embodiment of the present disclosure. In this case, Figure 2 Corresponding to the Figure 1 A cross section taken along line II' is shown.

[0013] Figure 3 is a schematic cross-sectional view showing a foldable display device according to an embodiment of the present disclosure. In this case, Figure 3 Corresponding to along Figure 1 A cross section taken along line II-II' is shown.

[0014] Figure 4 is a schematic cross-sectional view showing a foldable display device according to another embodiment of the present disclosure, and Figure 4 It shows that Figure 3 The view in the collapsed state of the folding region.

[0015] Figure 5is a schematic cross-sectional view showing a foldable display device according to another embodiment of the present disclosure. In this case, Figure 5 Corresponding to the Figure 1 A cross section taken along line II-II' is shown.

[0016] Figure 6 is a schematic cross-sectional view showing a foldable display device according to another embodiment of the present disclosure. In this case, Figure 6 Corresponding to the Figure 1 A cross section taken along line II-II' is shown.

[0017] Figure 7 is a schematic cross-sectional view showing a foldable display device according to another embodiment of the present disclosure. In this case, Figure 7 Corresponding to along Figure 1 A cross section taken along line II-II' is shown.

[0018] Figure 8 is a schematic cross-sectional view showing a foldable display device according to another embodiment of the present disclosure, and Figure 8 It shows that Figure 7 The view in the collapsed state of the folding region.

[0019] Fig. 9 is a schematic cross-sectional view showing a foldable display device according to another embodiment of the present disclosure. In this case, Fig. 9 Corresponding to along Figure 1 A cross section taken along line II-II' is shown.

[0020] Fig.10 is a schematic cross-sectional view showing a foldable display device according to another embodiment of the present disclosure, and Fig.10 It shows that Fig. 9 The view in the collapsed state of the folding region.

[0021] Fig.11 is a plan view showing in detail a light guide member of a foldable display device according to an embodiment of the present disclosure.

[0022] Fig.12 is a cross-sectional view of a light guide member of a foldable display device according to an embodiment of the present disclosure. In this case, Fig.12 is along Fig.11 A cross section taken along line III-III' is shown. DETAILED DESCRIPTION

[0023] The advantages and features of the present disclosure and their implementation methods will become clearer through the embodiments described below with reference to the accompanying drawings. However, the present disclosure can be implemented in different forms and should not be interpreted as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be thorough and complete, and the scope of the present disclosure will be fully conveyed to those skilled in the art. In addition, the present disclosure is limited only by the scope of the claims.

[0024] The shapes, sizes, proportions, angles, and quantities disclosed in the drawings used to describe the embodiments of the present disclosure are merely examples, and the present disclosure is not limited to the details shown. The same reference numerals refer to the same elements throughout. In the following description, when the detailed description of the relevant known functions or configurations is determined to be unnecessarily obscure the main points of the present disclosure, the detailed description will be omitted.

[0025] In the case where “including,” “having,” and “comprising” described in the present specification are used, another component may further be present unless “only” is used. Terms in the singular form may include plural forms unless otherwise specified.

[0026] When explaining an element, the element is interpreted as including an error range although there is no explicit description.

[0027] In describing a positional relationship, for example, when the positional order is described as “upper,” “above,” “lower,” “below,” and “next,” a case where there is no contact between them may be included unless “just” or “directly” is used.

[0028] If a first element is mentioned as being "on" a second element, it does not mean that the first element is substantially above the second element in the figure. The upper and lower parts of the relevant objects may change depending on the orientation of the objects. Therefore, the case where a first element is "on" a second element includes the case where the first element is "below" the second element in the figure or in the actual configuration as well as the case where the first element is "above" the second element.

[0029] When describing a time relationship, for example, when a time sequence is described as "after," "afterwards," "next," and "before," discontinuous cases may be included unless "directly" or "directly" is used.

[0030] It should be understood that although the terms "first", "second", etc. can be used in this article to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element can be referred to as a second element, and similarly, a second element can be referred to as a first element.

[0031] It should be understood that the term "at least one" includes all combinations related to any one item. For example, "at least one of a first element, a second element, and a third element" may include all combinations of two or more elements selected from the first element, the second element, and the third element, and each element of the first element, the second element, and the third element.

[0032] The features of the various embodiments of the present disclosure may be coupled or combined with each other in part or in whole, and may interoperate and technically drive each other in various ways. The various embodiments of the present disclosure may be implemented independently of each other, or may be implemented together in a mutually dependent relationship.

[0033] In the drawings, the same or similar elements are denoted by the same reference numerals even though they are depicted in different drawings.

[0034] In the embodiments of the present disclosure, for ease of explanation, the source electrode and the drain electrode are distinguished from each other. However, the source electrode and the drain electrode can be used interchangeably. Therefore, the source electrode can be a drain electrode, and the drain electrode can be a source electrode. Furthermore, the source electrode in any embodiment of the present disclosure can be a drain electrode in another embodiment of the present disclosure, and the drain electrode in any embodiment of the present disclosure can be a source electrode in another embodiment of the present disclosure.

[0035] In one or more embodiments of the present disclosure, for ease of explanation, the source region is distinguished from the source electrode, and the drain region is distinguished from the drain electrode. However, the embodiments of the present disclosure are not limited to this structure. For example, the source region may be the source electrode, and the drain region may be the drain electrode. In addition, the source region may be the drain electrode, and the drain region may be the source electrode.

[0036] Figure 1 is a plan view of a foldable display device according to an embodiment of the present disclosure.

[0037] like Figure 1 As shown, the foldable display device according to an embodiment of the present disclosure may include a display panel including a first substrate 100 and a second substrate 500 opposite to the first substrate 100 and combined with each other.

[0038] The first substrate 100 may include a thin film transistor and may be a transparent glass substrate or a plastic substrate. The first substrate 100 may include a display area AA in which an image is displayed and a non-display area IA in which an image is not displayed, depending on whether an image is displayed through pixels.

[0039] The display area AA may be an area in which an image is displayed, and may be a pixel array area, an active area, a pixel array unit, a display unit, or a screen. The display area AA may include a plurality of pixels P.

[0040] The plurality of pixels P may be arranged along each of a first direction X and a second direction Y intersecting the first direction X. Each of the plurality of pixels P may be a unit area in which actual light is emitted. For example, the plurality of pixels P may be arranged to have a pixel pitch PP along the first direction X. The pixel pitch PP may be a size of each pixel of the plurality of pixels P relative to the first direction X, a distance between one side of each of two pixels P adjacent along the first direction X, or a distance between central portions of two pixels P adjacent along the first direction X.

[0041] Each of the plurality of pixels P may include a plurality of adjacent sub-pixels SP. For example, the plurality of sub-pixels SP may constitute a plurality of pixels P. For example, the first direction X may be the first length direction, the long side length direction, the horizontal direction, or the first horizontal direction of the first substrate 100. For example, the second direction Y may be the second length direction, the short side length direction, the vertical direction, or the second vertical direction of the first substrate 100.

[0042] The non-display area IA may be an area in which an image is not displayed, and may be a peripheral circuit area, a signal supply area, an invalid area, or a frame area. The non-display area IA may be configured to surround the display area AA. The display panel or the first substrate 100 may further include a peripheral circuit unit 150 disposed in the non-display area IA. The peripheral circuit unit 150 may include a gate driving circuit connected to a plurality of sub-pixels SP.

[0043] The second substrate 500 may be configured to overlap the display area AA. The second substrate 500 may be combined to face the first substrate 100 by an adhesive member (or a transparent adhesive), or may be provided in a manner in which an organic material or an inorganic material is stacked on the first substrate 100. The second substrate 500 may be an upper substrate or an encapsulation substrate, and may correspond to the encapsulation first substrate 100.

[0044] The foldable display device according to an embodiment of the present disclosure may include a folding area FA in which folding is actually performed when folding or bending is performed, and a non-folding area NFA provided on one side or the other side of the folding area FA and in which separate folding is not performed.

[0045] Figure 2 is a schematic cross-sectional view showing a foldable display device according to an embodiment of the present disclosure. In this case, Figure 2 Corresponding to the Figure 1 A cross section taken along line II' is shown.

[0046] like Figure 2As shown in , the foldable display device according to an embodiment of the present disclosure may include a first substrate 100 , a circuit element layer 110 , a light emitting element layer 120 , an encapsulation layer 200 , a color filter 300 , a light guide member 400 , and a second substrate 500 .

[0047] The first substrate 100 may include a thin film transistor, and may be a first substrate, a base substrate, a lower substrate, a transparent glass substrate, a transparent plastic substrate, or a base member.

[0048] The first substrate 100 may include a circuit element layer 110, a planarization layer 119, and a light emitting element layer 120. The circuit element layer 110 may include a buffer layer 112, a pixel circuit, and a protective layer 118.

[0049] The buffer layer 112 may be disposed on the entire first surface (or front surface) of the first substrate 100. The buffer layer 112 may be used to block the material contained in the first substrate 100 from diffusing into the transistor layer during a high temperature process during the thin film transistor manufacturing process, or may also be used to prevent external moisture or humidity from penetrating into the light emitting element layer 120. Alternatively, the buffer layer 112 may be omitted in some cases.

[0050] The pixel circuit may include a driving thin film transistor disposed in the circuit area CA of each sub-pixel SP. The driving thin film transistor may include an active layer 113, a gate insulating layer 114, a gate electrode 115, an interlayer insulating layer 116, a drain electrode 117b, and a source electrode 117a.

[0051] The active layer 113 may be formed of a semiconductor material based on any one of amorphous silicon, polysilicon, oxide, and an organic material. The active layer 113 may include a channel region 113a, a drain region 113c, and a source region 113b.

[0052] The gate insulating layer 114 may be formed in an island shape only on the channel region 113 a of the active layer 113 , or may be formed on the entire front surface of the first substrate 100 or on the buffer layer 112 including the active layer 113 .

[0053] The gate electrode 115 may be disposed on the gate insulating layer 114 to overlap the channel region 113 a of the active layer 113 .

[0054] The interlayer insulating layer 116 may be formed on the gate electrode 115 and the drain region 113c and the source region 113b of the active layer 113. The interlayer insulating layer 116 may be formed on the entire front surface of the first substrate 100 or on the buffer layer 112. For example, the interlayer insulating layer 116 may be formed of an inorganic material or an organic material.

[0055] The drain electrode 117b may be disposed on the interlayer insulating layer 116 to be electrically connected to the drain region 113c of the active layer 113. The source electrode 117a may be disposed on the interlayer insulating layer 116 to be electrically connected to the source region 113b of the active layer 113.

[0056] The pixel circuit may further include at least one capacitor and at least one switching thin film transistor disposed in the circuit area CA together with the driving thin film transistor.

[0057] The foldable display device according to the present disclosure may further include a light shielding layer 111 disposed under at least one active layer 113 of the driving thin film transistor and the switching thin film transistor. The light shielding layer 111 may be configured to minimize or prevent a change in the threshold voltage of the thin film transistor due to external light.

[0058] The protective layer 118 may be configured on the pixel circuit. For example, the protective layer 118 may be configured to surround the drain electrode 117b, the source electrode 117a and the interlayer insulating layer 116 of the driving thin film transistor. For example, the protective layer 118 may be formed of an inorganic insulating material and may be expressed as a passivation layer or the like.

[0059] The planarization layer 119 may be disposed on the circuit element layer 110. The planarization layer 119 may be formed on the entire display area and the remaining non-display area except the pad area. For example, the planarization layer 119 may include an extension portion (or extension portion) extending or extending from the display area to the non-display area except the pad area. Therefore, the planarization layer 119 may have a size relatively larger than that of the display area.

[0060] The planarization layer 119 according to an embodiment may be formed to have a relatively large thickness to provide a planarized surface on the circuit element layer 110. For example, the planarization layer 119 may be made of an organic material such as photo acrylic, benzocyclobutene, polyimide, fluororesin, or the like.

[0061] Meanwhile, although not shown in detail, the planarization layer 119 may include a light extraction unit disposed in each sub-pixel SP. The light extraction unit may be formed in the planarization layer 119 to overlap with the light emitting area EA defined in the sub-pixel area SPA of each sub-pixel SP. In this case, the light extraction unit may be formed in the planarization layer 119 to have a curved portion (or uneven portion). In this case, the curved portion may include a plurality of concave portions and convex portions. The light extraction unit may be formed in the planarization layer 119 to have a curved (or uneven) shape. When the light extraction unit is disposed in the planarization layer 119, the external extraction efficiency of the light emitted from the light emitting element layer 120 may be increased.

[0062] The light emitting element layer 120 may overlap with the light emitting area EA of each sub-pixel SP. The light emitting element layer 120 according to the embodiment may include a first electrode E1, an emission layer EL, and a second electrode E2. For example, the first electrode E1, the emission layer EL, and the second electrode E2 may be configured to emit light to the second substrate 500 according to a top emission method. However, the present disclosure is not limited thereto, and may be configured to emit light to the first substrate 100 according to a bottom emission method.

[0063] The first electrode E1 may be formed on the planarization layer 119 of the sub-pixel area SPA to be electrically connected to the source electrode 117a of the driving thin film transistor. One end of the first electrode E1 adjacent to the circuit area CA may be electrically connected to the source electrode 117a of the driving thin film transistor through an electrode contact hole CH provided in the planarization layer 119 and the protective layer 118.

[0064] The emission layer EL may be formed on the first electrode E1 to be in direct contact with the first electrode E1.

[0065] The emission layer EL according to the embodiment may include two or more organic emission layers for emitting white light. For example, the emission layer EL may include a first organic emission layer and a second organic emission layer for emitting white light by mixing the first light and the second light.

[0066] The second electrode E2 may be formed on the emission layer EL to be in direct contact with the emission layer EL. The second electrode E2 may be formed (or deposited) on the emission layer EL to have a relatively thin thickness compared with the emission layer EL.

[0067] The first electrode E1 according to an embodiment of the present disclosure may include a metal material having a high reflectivity so as to reflect the light emitted from the emission layer EL and incident thereto toward the second substrate 500. For example, the first electrode E1 may include a single-layer structure or a multi-layer structure formed of any one material selected from aluminum (Al), silver (Ag), molybdenum (Mo), gold (Au), magnesium (Mg), calcium (Ca), or barium (Ba). The first electrode E1 may be an anode.

[0068] Meanwhile, although not shown in detail in the drawings, when the light extraction unit is provided in the planarization layer 119, the first electrode E1, the emission layer EL, and the second electrode E2 may have a surface shape directly following the surface morphology of the light extraction unit including a plurality of convex portions and a plurality of concave portions. For example, the first electrode E1, the emission layer EL, and the second electrode E2 are formed into a conformal shape directly following the surface shape (or morphology) of the light extraction unit by a deposition process of a transparent conductive material, and thus may have a cross-sectional structure identical to the shape of the light extraction unit.

[0069] The foldable display device according to the exemplary configuration of the present disclosure may further include a bank layer 121. The bank layer 121 may be provided on the edges of the planarization layer 119 and the first electrode E1. The bank layer 121 may be formed of a transparent material or an opaque material. For example, the bank layer 121 may be a transparent bank layer or a black bank layer. For example, the bank layer 121 may be formed of a photosensitizer including a black pigment, and in this case, the bank layer 121 may also serve as a light blocking member between adjacent sub-pixels SP.

[0070] The encapsulation layer 200 may be formed on the first substrate 100 to surround the light emitting element layer 120. The encapsulation layer 200 may be formed on the second electrode E2. For example, the encapsulation layer 200 may surround the display region. The encapsulation layer 200 may protect the thin film transistor and the emission layer EL from external impacts, and may be used to prevent oxygen and / or moisture, and other particles from penetrating into the emission layer EL.

[0071] The encapsulation layer 200 according to the present disclosure may include a plurality of inorganic encapsulation layers. In addition, the encapsulation layer 200 may further include at least one organic encapsulation layer interposed between the plurality of inorganic encapsulation layers. The encapsulation layer 200 according to another embodiment may be changed to a filler surrounding the entire display area, and in this case, the second substrate 500 may be bonded to the first substrate 100 through the filler. The filler may include a getter material that absorbs oxygen and / or moisture.

[0072] The color filter 300 may be disposed on the encapsulation layer 200. Specifically, it may be disposed between the encapsulation layer 200 and the second substrate 500. The color filter 300 may be disposed between the encapsulation layer 200 and the second substrate 500 to overlap at least one emission area EA. For example, the color filter 300 may be directly formed on the upper surface of the encapsulation layer 200 to overlap with the emission area EA. In this case, the color filter 300 may directly contact the upper surface of the encapsulation layer 200. However, the present disclosure is not limited thereto, and the color filter 300 may be disposed on the inner surface of the upper surface of the second substrate 500 facing the encapsulation layer 200 to overlap with the emission area EA. For example, the second substrate 500 having the color filter 300 may be bonded to the encapsulation layer 200 via a transparent adhesive member.

[0073] The color filter 300 may have a size wider than that of the emission area EA. For example, the color filter 300 may have a size corresponding to the entire sub-pixel area SPA of each sub-pixel SP, thereby reducing light leakage between adjacent sub-pixels SP.

[0074] The color filter 300 according to the present disclosure may be configured to transmit the wavelength of the color set in the sub-pixel SP. For example, when one pixel P is composed of the first to fourth sub-pixels, the color filter 300 may include a red color filter set in the first sub-pixel emitting red light, a green color filter set in the third sub-pixel emitting green light, and a blue color filter set in the fourth sub-pixel emitting blue light. The second sub-pixel emitting white light may not include a color filter layer or may include a transparent material for step compensation, thereby emitting white light.

[0075] The black matrix 310 may be disposed between the plurality of color filters 300 .

[0076] The black matrix 310 may be arranged to overlap with the remaining area of ​​each sub-pixel SP except the emission area EA. Optionally, the remaining area of ​​each sub-pixel SP except the emission area EA may include a stacked structure of at least two color filters instead of the black matrix 310. For example, the remaining area of ​​each sub-pixel SP except the emission area EA may include a stacked structure of at least two of a red color filter, a green color filter, and a blue color filter. The stacked structure of at least two color filters may replace the black matrix 310 to prevent color mixing between adjacent sub-pixels SP.

[0077] The second substrate 500 may be disposed on the color filter 300. The second substrate 500 may be made of a plastic material, a glass material, or a metal material. Meanwhile, when the encapsulation layer 200 includes a plurality of inorganic encapsulation layers, the second substrate 500 may be omitted.

[0078] Optionally, when the encapsulation layer 200 is changed to a filler, the second substrate 500 may be combined with the filler. In this case, the second substrate 500 may be made of a plastic material, a glass material, or a metal material.

[0079] The light guide member 400 may be disposed between the color filter 300 and the second substrate 500. The light guide member 400 may be disposed or arranged on a first surface of the second substrate 500, for example, a lower surface (or light emitting surface) opposite to an upper surface.

[0080] The light guide member 400 according to an embodiment of the present disclosure may be bonded to the lower surface of the second substrate 500 via an adhesive member (or a first transparent adhesive member) 450. For example, the light guide member 400 may be bonded to the entire lower surface of the second substrate 500 via the adhesive member 450. In this case, the light guide member 400 may have the same size as the lower surface of the second substrate 500.

[0081] The light guide member 400 may be configured to improve the black visibility characteristics due to the reflection of external light in the non-driven or closed state of the foldable display device. For example, in the non-driven or closed state of the foldable display device, the light incident from the outside is reflected by the electrodes and wirings of the circuit element layer 110 to form reflected light, and the reflected light may form a rainbow moire (or rainbow dyeing pattern) having rainbow colors and radially extending and / or a radially shaped circular ring pattern due to the dispersion characteristics of light according to the diffraction characteristics.

[0082] The reflected light may cause multiple interference and / or enhanced interference of light according to the difference in the refraction angle of each wavelength to generate rainbow moire and / or donut patterns in the form of radiation, thereby reducing black visibility characteristics.

[0083] The light guide member 400 according to an embodiment of the present disclosure may be configured to diffract and / or scatter external light incident into the display device from the outside through the second substrate 500 based on the principle of light refraction according to a cross shape with a refractive index difference, or to re-disperse (or disperse) the diffraction dispersion spectrum of the reflected light. For example, the light guide member 400 may suppress or minimize the occurrence of the radial rainbow moire phenomenon by reducing the intensity of the diffraction dispersion spectrum or / or re-dispersing the diffraction dispersion spectrum, by mixing between adjacent spectrums according to the diffraction order of the reflected light to greatly expand the size of the spectrum.

[0084] The light guide member 400 may include a lens pattern. The lens pattern may diffract and / or scatter external light incident on the light emitting element layer 120 from the outside, or diffract and / or scatter reflected light based on the principle of light refraction with a refractive index difference. Therefore, the appearance of rainbow moire and / or ring pattern can be reduced or minimized by eliminating or minimizing multiple interferences and / or enhancing interferences of reflected light, and according to an embodiment of the present disclosure, the reduction of black visibility characteristics due to external light reflection can be reduced, and true black can be achieved in a non-driven or off state. For example, the light guide member 400 may be a light guide pattern unit, a light refraction unit, a light refraction member, a spectral dispersion unit, a spectral reduction unit, or a diffraction spectral dispersion unit.

[0085] Meanwhile, although not shown, the foldable display device according to an embodiment of the present disclosure may further include a polarizing member. The polarizing member may be disposed on the light guide member 400 to block light introduced from the outside from being reflected by the pixel circuit or the like.

[0086] By including the light guide member 400, the foldable display device according to an embodiment of the present disclosure can improve the black visibility characteristics due to the reflection of external light, and can minimize or reduce the occurrence of rainbow moire and annular moire phenomena, thereby achieving true black in a non-driven or closed state.

[0087] Figure 3 is a schematic cross-sectional view showing a foldable display device according to an embodiment of the present disclosure. Meanwhile, the configurations of the first substrate 100, the circuit element layer 110, the light emitting element layer 120, the encapsulation layer 200, the color filter 300 and the second substrate 500 are the same as those described above. Figure 2 , so their repeated description will be omitted.

[0088] like Figure 3 As shown, the foldable display device according to an embodiment of the present disclosure may include a first substrate 100 , a circuit element layer 110 , a light emitting element layer 120 , an encapsulation layer 200 , a color filter 300 , a light guide member 400 , and a second substrate 500 .

[0089] According to an embodiment of the present disclosure, the light guide member 400 may include a refraction layer 411 , a filling layer 412 , and an intermediate layer 413 .

[0090] The light guide member 400 may include various polymer materials, such as polyacrylate-based polymers, polymethyl methacrylate-based polymers, polyurethane-based polymers, polyvinyl alcohol-based polymers, polyvinyl chloride-based polymers, and polyamide-based polymers. However, the material of the light guide member 400 is not limited to the polymers exemplified above, but may include various materials according to the technical level of the art.

[0091] The refractive layer 411 may be disposed in the non-folding area NEA.

[0092] The refractive layer 411 may include a plurality of lens patterns L1 to Ln. In this case, each of the plurality of lens patterns L1 to Ln may include a lower surface BA1 to BAn corresponding to a portion of the lower surface 400b of the light guide member 400 and a convex surface VA1 to VAn convexly formed from the lower surface BA1 to BAn. For example, among the plurality of lens patterns L1 to Ln, the first lens pattern L1 may include a first lower surface BA1 and a first convex surface VA1 convexly formed from the first lower surface BA1.

[0093] According to an embodiment of the present disclosure, the first lens pattern L1 may include a first lower surface BA1 and a first convex surface VA1, and thus may be set to a hemispherical shape. Similarly, the plurality of lens patterns L1 to Ln may include lower surfaces BA1 to BAn and convex surfaces VA1 to VAn formed convexly from the lower surfaces BA1 to BAn, and thus may be set to a hemispherical shape. Meanwhile, the shapes of the plurality of lens patterns L1 to Ln are not limited to a hemispherical shape, and may be formed such that two or more of the plurality of lens patterns L1 to Ln overlap, and the shapes of the plurality of lens patterns L1 to Ln may be set to a polygonal shape, and various shapes may be selected according to the technical level of the art.

[0094] The refractive layer 411 may be formed in an atypical shape and may be arranged in an irregular arrangement. The refractive layer 411 may prevent the appearance of moire (e.g., rainbow moire or annular moire) by reflecting external light introduced from the outside of the foldable display device according to an embodiment of the present disclosure through a plurality of electrodes, wirings, and circuits provided in the display device. Specifically, the refractive layer 411 may be arranged irregularly in an atypical shape, thereby preventing or minimizing the appearance of moire perceived by a certain regularity. At the same time, the reference Fig.11 A state in which the plurality of lens patterns L1 to Ln provided in the refractive layer 411 are irregularly arranged in an atypical shape is described in more detail.

[0095] The filling layer 412 may be disposed in the non-folding area NFA.

[0096] The filling layer 412 may be disposed on the refractive layer 411 or may be disposed between the refractive layers 411. The filling layer 412 may include an upper surface UA corresponding to the upper surface 400a of the light guide member 400, and a plurality of concave surfaces CA1 to CAn concavely formed from the upper surface UA.

[0097] The plurality of concave surfaces CA1 to CAn of the filling layer 412 may correspond to the plurality of convex surfaces VA1 to VAn of the refractive layer 411. More specifically, the first concave surface CA1 of the plurality of concave surfaces CA1 to CAn of the filling layer 412 may correspond to the first convex surface VA1 of the refractive layer 411. Likewise, the plurality of concave surfaces CA1 to CAn may correspond to the plurality of convex surfaces VA1 to VAn.

[0098] A partial area of ​​the filling layer 412 may be disposed between the refractive layers 411 and may be disposed between the plurality of lens patterns L1 to Ln of the refractive layer 411. In this case, the partial area of ​​the filling layer 412 may not have the concave surfaces CA1 to CAn, and further, the partial area of ​​the filling layer 412 may not correspond to the convex surfaces VA1 to VAn of the refractive layer 411. In this case, the partial area of ​​the filling layer 412 may contact the lower surface 400b of the light guide member 400.

[0099] According to an embodiment of the present disclosure, the refractive index of the filling layer 412 and the refractive index of the refractive layer 411 may have a predetermined difference. Specifically, the refractive layer 411 may have a first refractive index, and the filling layer 412 may have a second refractive index different from the first refractive index. For example, the difference between the second refractive index of the filling layer 412 and the first refractive index of the refractive layer 411 may be 0.07. However, the difference between the second refractive index and the first refractive index is not limited thereto.

[0100] By forming in this manner, it is possible to prevent or minimize annular moire or rainbow moire generated when light introduced from the outside of the light guide member 400 is reflected by electrodes and wirings inside the foldable display device according to an embodiment of the present disclosure.

[0101] The intermediate layer 413 may be disposed in the folding area FA, and may be disposed between the refractive layer 411 and the filling layer 412 disposed in the non-folding area NFA.

[0102] The intermediate layer 413 may be continuously disposed in the folding area FA from the lower surface 400b of the light guide member 400 to the upper surface 400a of the light guide member 400. By forming in this manner, even when the folding area FA is folded, a lifting phenomenon or a peeling phenomenon of the light guide member 400 due to folding may be eliminated or minimized.

[0103] According to an embodiment of the present disclosure, the intermediate layer 413 may extend in the second direction Y, and may include a plurality of first portions 413 a and a plurality of second portions 413 b alternately formed along the first direction X.

[0104] As described above, each of the first portion 413 a and the second portion 413 b may be continuously provided from the lower surface 400 b of the light guide member 400 to the upper surface 400 a of the light guide member 400 .

[0105] According to an embodiment of the present disclosure, the modulus of the first portion 413a may be smaller than the modulus of the second portion 413b. Since the first portion 413a having a relatively small modulus and the second portion 413b having a relatively large modulus are formed to cross each other along the first direction X, even when the folding area FA is folded, the lifting phenomenon or peeling phenomenon of the light guide member 400 caused by folding can be removed or minimized.

[0106] In addition, since the first portion 413a having a relatively small modulus and the second portion 413b having a relatively large modulus are formed to cross along the first direction X, the light guide member 400 disposed in the folding area FA, that is, the intermediate layer 413 can remain flat without curling (or sagging or bending).

[0107] According to an embodiment of the present disclosure, the first portion 413a may include the same material as the refractive layer 411, and the second portion 413b may include the same material as the filling layer 412. Therefore, the modulus of the first portion 413a may be the same as the modulus of the refractive layer 411, and the modulus of the second portion 413b and the modulus of the filling layer 412 may be the same. However, the materials of the first portion 413a and the second portion 413b are not limited thereto, and the first portion 413a may include a material different from that of the refractive layer 411, and the second portion 413b may include a material different from that of the filling layer 412.

[0108] Figure 4 is a schematic cross-sectional view showing a foldable display device according to another embodiment of the present disclosure, and Figure 4 It is shown Figure 3 A diagram showing a state where the folding area is folded.

[0109] like Figure 4 As shown, when the foldable display device according to an embodiment of the present disclosure is folded, the non-folding area NFA is not folded alone, and the folding area FA may be folded along the folding axis FX.

[0110] When the folding area FA is folded, a relatively large force may be applied to the folding area FA compared to the non-folding area NFA. According to the present disclosure, since the light guide member 400 includes the intermediate layer 413 in the area corresponding to the folding area FA, even when the folding area FA is folded, the phenomenon in which the light guide member 400 is lifted or peeled off can be removed or minimized.

[0111] Specifically, the intermediate layer 413 may include a continuous area, wherein a plurality of first portions 413a and a second portion 413b have the same modulus from the upper surface 400a of the light guide member 400 to the lower surface 400b of the light guide member 400 in the folding area FA, and the plurality of first portions 413a and the plurality of second portions 413b are alternately arranged, so that even if the folding area FA is folded, the phenomenon in which the light guide member 400 is lifted or peeled off can be eliminated or minimized.

[0112] at the same time, Figure 4 Only a form in which the upper surface 400 a of the light guide member 400 is folded to be located inside is illustrated, but the present disclosure is not limited thereto, and the upper surface 400 a of the light guide member may be folded to be located outside.

[0113] Figure 5 is a schematic cross-sectional view showing a foldable display device according to another embodiment of the present disclosure. Figure 5 In addition to the configuration of the first and second parts of the intermediate layer arranged in the folding area, Figure 3The structures are the same, so the following will mainly describe the different structures.

[0114] like Figure 5 As shown, according to another embodiment of the present disclosure, the middle layer 413 of the light guide member 400 can be arranged in the folding area FA. In this case, the first part 413a of the middle layer 413 can be arranged in the shape of an inverted triangle. Specifically, the cross section of the first part 413a of the middle layer 413 can be arranged in an inverted triangle. Therefore, the first part 413a can have a relatively large area on the upper surface 400a of the light guide member 400, and can have a relatively narrow area on the lower surface 400b of the light guide member 400.

[0115] The second portion 413b of the intermediate layer 413 may be provided in a shape corresponding to the first portion 413a. Therefore, the second portion 413b may have a relatively narrow area on the upper surface 400a of the light guide member 400 and may have a relatively large area on the lower surface 400b of the light guide member 400.

[0116] According to an embodiment of the present disclosure, in the folding area FA, the intermediate layer 413 can be continuously set from the upper surface 400a of the light guide member 400 to the lower surface 400b of the light guide member 400, and a plurality of first parts 413a and a plurality of second parts 413b intersect, so that even if folding or bending occurs in the folding area FA, the occurrence of lifting or peeling in the light guide member 400 due to the stress applied to the folding area FA can be minimized.

[0117] Figure 6 is a schematic cross-sectional view showing a foldable display device according to another embodiment of the present disclosure. Figure 6 In addition to the configuration of the first and second parts of the intermediate layer arranged in the folding area, Figure 3 The embodiments are the same, so the following will mainly describe different configurations.

[0118] like Figure 6 As shown, according to another embodiment of the present disclosure, the middle layer 413 of the light guide member 400 can be arranged in the folding area FA. In this case, the first portion 413a of the middle layer 413 can be arranged in the shape of an inverted trapezoid. Specifically, the cross-section of the first portion 413a of the middle layer 413 can be arranged in the shape of an inverted trapezoid. Therefore, the first portion 413a can have a relatively large area on the upper surface 400a of the light guide member 400, and can have a relatively narrow area on the lower surface 400b of the light guide member 400.

[0119] The second portion 413b of the intermediate layer 413 may be provided in a shape corresponding to the first portion 413a. Therefore, the second portion 413b may have a relatively narrow area on the upper surface 400a of the light guide member 400 and may have a relatively large area on the lower surface 400b of the light guide member 400.

[0120] According to an embodiment of the present disclosure, in the folding area FA, the intermediate layer 413 can be continuously set from the upper surface 400a of the light guide member 400 to the lower surface 400b of the light guide member 400, and a plurality of first parts 413a and a plurality of second parts 413b intersect, so that even if folding or bending occurs in the folding area FA, the occurrence of lifting or peeling in the light guide member 400 due to the stress applied to the folding area FA can be minimized.

[0121] Figure 7 is a schematic cross-sectional view showing a foldable display device according to another embodiment of the present disclosure. Figure 7 In addition to the structure of the light guide member, the embodiment of Figure 3 The embodiments are the same, so the following will mainly describe different configurations.

[0122] like Figure 7 As shown, the intermediate layer 413 may be disposed in the folding area FA, and may include a third portion 413c and a fourth portion 413d.

[0123] The third portion 413c may include a plurality of lens patterns mL1 to mLn. In this case, each of the plurality of lens patterns mL1 to mLn may include a lower surface mBA1 to mBAn corresponding to a portion of the lower surface 400b of the light guide member 400 and a convex surface mVA1 to mVAn convexly formed from the lower surface mBA1 to mBAn. For example, among the plurality of lens patterns mL1 to mLn, the first lens pattern mL1 may include a first lower surface mBA1 and a first convex surface mVA1 convexly formed from the first lower surface mBA1.

[0124] According to an embodiment of the present disclosure, the first lens pattern mL1 may include a first lower surface mBA1 and a first convex surface mVA1, and thus may be set to a hemispherical shape. Similarly, the plurality of lens patterns mL1 to mLn may include lower surfaces mBA1 to mBAn and convex surfaces mVA1 to mVAn protruding from the lower surfaces mBA1 to mBAn, and thus may be set to a hemispherical shape. Meanwhile, the shapes of the plurality of lens patterns mL1 to mLn are not limited to a hemispherical shape, and may be formed such that two or more of the plurality of lens patterns mL1 to mLn overlap, and the shapes of the plurality of lens patterns mL1 to mLn may be set to a polygonal shape, and various shapes may be selected according to the level of the art.

[0125] The third portion 413c of the intermediate layer 413 may be formed in an atypical shape and may be arranged in an irregular arrangement. The third portion 413c may prevent the occurrence of moire (e.g., rainbow moire or ring moire) by reflecting external light introduced from the outside of the foldable display device according to an embodiment of the present disclosure through a plurality of electrodes, wirings, and circuits provided in the display device. Specifically, because the third portion 413c is irregularly arranged in an atypical shape, the occurrence of moire that is recognized by a certain regularity may be prevented or minimized. At the same time, reference will be made to Fig.11 A state in which the plurality of lens patterns mL1 to mLn provided in the third portion 413 c are irregularly arranged in an atypical shape is described in more detail.

[0126] The fourth portion 413 d of the intermediate layer 413 may be disposed in the non-folding area NFA.

[0127] The fourth portion 413d may be disposed on the third portion 413c or may be disposed between the third portions 413c. The fourth portion 413d may include a top surface mUA corresponding to the top surface 400a of the light guide member 400 and a plurality of concave surfaces mCA1 to mCAn formed to be concave from the top surface mUA.

[0128] The plurality of concave surfaces mCA1 to mCAn of the fourth portion 413d may correspond to the plurality of convex surfaces mVA1 to mVAn of the third portion 413c. Specifically, the first concave surface mCA1 among the plurality of concave surfaces mCA1 to mCAn of the fourth portion 413d may correspond to the first convex surface mVA1 of the third portion 413c. Likewise, the plurality of concave surfaces mCA1 to mCAn may correspond to the plurality of convex surfaces mVA1 to mVAn.

[0129] A partial area of ​​the fourth portion 413d may be disposed between the third portions 413c and may be disposed between the plurality of lens patterns mL1 to mLn of the third portion 413c. In this case, a partial area of ​​the fourth portion 413d may not have the concave surfaces mCA1 to mCAn, and further, a partial area of ​​the fourth portion 413d may not correspond to the convex surfaces mVA1 to mVAn of the third portion 413c. In this case, a partial area of ​​the fourth portion 413d may contact the lower surface 400b of the light guide member 400.

[0130] According to an embodiment of the present disclosure, the refractive index of the fourth portion 413d and the refractive index of the third portion 413c may have a predetermined difference. Specifically, the third portion 413c may have a third refractive index, and the fourth portion 413d may have a fourth refractive index different from the third refractive index. For example, the difference between the fourth refractive index of the fourth portion 413d and the third refractive index of the third portion 413c may be 0.07. However, the difference between the third refractive index and the fourth refractive index is not limited thereto.

[0131] By forming in this manner, it is possible to prevent or minimize annular moire or rainbow moire generated when light introduced from the outside of the light guide member 400 is reflected by electrodes and wirings inside the foldable display device according to an embodiment of the present disclosure.

[0132] According to an embodiment of the present disclosure, the difference between the modulus of the third portion 413c and the modulus of the fourth portion 413d may be relatively smaller than the difference between the modulus of the refractive layer 411 and the modulus of the filling layer 412. For example, the third portion 413c and the fourth portion 413d may include materials having the same modulus. Therefore, the intermediate layer 413 including the third portion 413c and the fourth portion 413d may include a continuous region having the same modulus from the lower surface 400b of the light guide member 400 to the upper surface 400a of the light guide member 400.

[0133] By forming in this manner, even if folding or bending occurs in the folding area FA, a lifting phenomenon or a peeling phenomenon occurring in the light guide member 400 due to stress applied to the folding area FA may be minimized.

[0134] Figure 8 is a schematic cross-sectional view showing a foldable display device according to another embodiment of the present disclosure, and Figure 8 It shows that Figure 7 A diagram showing a state where the folding area is folded.

[0135] like Figure 8 As shown, when the foldable display device according to an embodiment of the present disclosure is folded, the non-folding area NFA is not folded alone, and the folding area FA may be folded along the folding axis FX.

[0136] When the folding area FA is folded, a relatively large force may be applied to the folding area FA compared to the non-folding area NFA. According to the present disclosure, since the light guide member 400 includes the intermediate layer 413 in the area corresponding to the folding area FA, even when the folding area FA is folded, the phenomenon in which the light guide member 400 is lifted or peeled off can be removed or minimized.

[0137] Specifically, since the intermediate layer 413 includes a continuous area having the same modulus from the upper surface 400a of the light guide member 400 to the lower surface 400b of the light guide member 400 in the folding area FA, even if the folding area FA is folded, the phenomenon in which the light guide member 400 is lifted or peeled off can be eliminated or minimized.

[0138] at the same time, Figure 8 Only a form in which the upper surface 400 a of the light guide member is folded to be located at the inner side is shown, but the present disclosure is not limited thereto, and the upper surface 400 a of the light guide member may be folded to be located at the outer side.

[0139] Fig. 9 is a schematic cross-sectional view showing a foldable display device according to another embodiment of the present disclosure. Fig. 9 In addition to the structure of the intermediate layer, the embodiment Figure 7 The embodiments are the same, so the following will mainly describe different configurations.

[0140] like Fig. 9 As shown, the folding area FA may include a first folding area FA1, a second folding area FA2a, and a third folding area FA2b.

[0141] The first folding area FA1 may be disposed at the center of the folding area FA. Specifically, the first folding area FA1 may overlap with the folding axis FX. In this case, the folding axis FX may be defined as an axis that serves as a folding center when the foldable display device according to an embodiment of the present disclosure is folded. Therefore, the folding area FA may be folded around the folding axis FX.

[0142] The first folding area FA1 may include a portion receiving a relatively maximum stress in the folding area FA when the folding area FA is folded. In this case, for example, the portion receiving a relatively maximum stress during folding may be the center of the folding area FA or the first folding area FA1.

[0143] The second folding area FA2a and the third folding area FA2b may be disposed on one side (e.g., the right side) of the first folding area FA1 and the other side (e.g., the left side) of the first folding area FA1. In this case, when the foldable display device is folded, the second folding area FA2a and the third folding area FA2b may receive relatively less stress than the first folding area FA1. In other words, the second folding area FA2a and the third folding area FA2b may not include a portion that is subjected to relatively maximum stress when folded.

[0144] According to another embodiment of the present disclosure, Figure 7Differently, the intermediate layer 413 may be disposed only in a partial area of ​​the folding area FA, for example, in the first folding area FA1. Therefore, the third portion 413c and the fourth portion 413d of the intermediate layer 413 may be disposed in the first folding area FA1, and may not be disposed in the second folding area FA2a and the third folding area FA2b. Figure 7 , so their repeated description will be omitted.

[0145] according to Figure 3 The refraction layer 411 and the filling layer 412 of the embodiment may be respectively disposed in the second folding area FA2a and the third folding area FA2b. Therefore, the refraction layer 411 including the plurality of lens patterns L1 to Ln and the filling layer 412 disposed on the refraction layer 411 and corresponding to the plurality of lens patterns L1 to Ln of the refraction layer 411 may be respectively disposed in the second folding area FA2a and the third folding area FA2b. Therefore, the plurality of lens patterns L1 to Ln of the refraction layer 411 may be continuous from the non-folding area NFA to the second folding area FA2a (or the third folding area FA2b), and the filling layer 412 may be continuous from the non-folding area NFA to the second folding area FA2a (or the third folding area FA2b).

[0146] At the same time, due to the refraction layer 411 and the filling layer 412 Figure 3 , so their repeated description will be omitted.

[0147] According to another embodiment of the present disclosure, the modulus of the filling layer 412 disposed in the second folding area FA2a and the third folding area FA2b may be relatively greater than the modulus of the fourth portion 413d of the intermediate layer 413 disposed in the first folding area FA1. Therefore, since the proportion of the filling layer 412 having a relatively large modulus increases, the overall strength of the light guide member 400 may be increased.

[0148] Meanwhile, although not specifically shown, in accordance with the above Figure 3 , Figure 5 and Figure 6 In the embodiment of the present invention, the intermediate layer may be arranged only in the first folding area, such as according to Fig. 9 As in the embodiment of .

[0149] Fig.10 is a schematic cross-sectional view showing a foldable display device according to another embodiment of the present disclosure, and Fig.10 It shows that Fig. 9 A diagram showing a state where the folding area is folded.

[0150] At the same time, due to Fig.10In addition to the folding area including the first folding area to the third folding area, the embodiment according to Figure 8 The embodiments are the same, and the different structures will be mainly described below.

[0151] like Fig.10 As shown, the folding area FA may include a first folding area FA1, a second folding area FA2a, and a third folding area FA2b.

[0152] In this case, when the folding area FA is folded, the first folding area FA1 may overlap with the folding axis FX as the folding center axis. In this case, when the folding area FA is folded, a portion of a virtual straight line VL passing through the folding axis FX and extending in the first direction X may be subjected to relatively maximum stress. Therefore, since the virtual straight line VL passing through the folding axis FX and extending in the first direction X intersects with the center of the first folding area FA1, the first folding area FA1 may include a portion subjected to relatively maximum stress when the folding area FA is folded.

[0153] That is, a relatively greater stress may be applied to the light guide member 400 disposed in the first folding area FA1 compared to the light guide members 400 disposed in the second and third folding areas FA2a and FA2b.

[0154] Fig.11 is a plan view showing in detail a light guide member of a foldable display device according to an embodiment of the present disclosure. And, Fig.12 is along Fig.11 A cross-sectional view taken along line III-III' is shown.

[0155] In the following, reference will be made to Fig.11 and Fig.12 The relationship between the plurality of lens patterns L1 to Ln of the refractive layer 411 provided in the light guide member 400 according to the embodiment of the present disclosure is described. Meanwhile, the relationship between the plurality of lens patterns L1 to Ln of the refractive layer 411 can also be applied to the light guide member 400 according to the embodiment of the present disclosure. Figure 7 and Fig. 9 The relationship between the third portion 413c of the middle layer 413, specifically, the relationship between the plurality of lens patterns mL1 to mLn of the third portion 413c.

[0156] refer to Fig.11 and Fig.12 , the light guide member 400 according to an embodiment of the present disclosure may include a refraction layer 411 and a filling layer 412 .

[0157] like Figure 3As described in the foregoing, the refraction layer 411 includes a plurality of lens patterns L1 to Ln, and the plurality of lens patterns L1 to Ln include a material having a first refractive index and include an atypical arrangement structure having a hemispherical shape including lower surfaces BA1 to BAn and convex surfaces VA1 to VAn. Therefore, a repeated description thereof will be omitted.

[0158] The center portion CP of one or more of the plurality of lens patterns L1 to Ln may be spaced apart from at least one of the first straight line SL1, the second straight line SL2, the first diagonal straight line DSL1, and the second diagonal line DSL2. For example, the pitch P1 to Pn between two adjacent lens patterns of the plurality of lens patterns L1 to Ln may be different along one or more of the first direction X, the second direction Y, and the diagonal direction between the first direction X and the second direction Y. For example, the plurality of lens patterns L1 to Ln may be configured to have different pitches P1 to Pn along at least one of the first direction X, the second direction Y, and the diagonal direction between the first direction X and the second direction Y.

[0159] At least some of the plurality of lens patterns L1 to Ln according to another embodiment of the present disclosure may be arranged to be connected to each other. At least some of the plurality of lens patterns L1 to Ln may be arranged to be non-overlapping and connected to each other. The plurality of lens patterns L1 to Ln may be configured to be non-overlapping and connected to each other along at least one of the first direction X, the second direction Y, and the diagonal direction between the first direction X and the second direction Y. For example, the bottom surface BA1 to BAn of each of the plurality of lens patterns L1 to Ln may be connected to (or contact) the bottom surfaces BA1 to BAn of the lens patterns L1 to Ln adjacent to each other along at least one of the first direction X, the second direction Y, and the diagonal direction between the first direction X and the second direction Y. For example, the end portions EP1 to EPn of the lower surfaces BA1 to BAn of each of the plurality of lens patterns L1 to Ln may be connected to (or contact) the end portions EP1 to EPn of the lower surfaces BA1 to BAn adjacent to each other along one or more of the first direction X, the second direction Y, and the diagonal direction between the first direction X and the second direction Y.

[0160] Meanwhile, although not shown in detail in the drawings, the plurality of lens patterns L1 to Ln may be spaced apart from each other by a predetermined distance. In this case, the ends EP1 to EPn of the bottom surfaces BA1 to BAn of the plurality of lens patterns L1 to Ln may not be connected to the ends EP1 to EPn of the bottom surfaces BA1 to BAn adjacent to each other along at least one of the first direction X, the second direction Y, and the diagonal direction between the first direction X and the second direction Y. In this case, the filling layer 412 may be disposed in the region between the plurality of lens patterns L1 to Ln, and thus, the filling layer 412 may contact a portion of the bottom surface 400b of the light guide member 400.

[0161] Each of the plurality of lens patterns L1 to Ln may have a different diameter D1 to Dn in the range of 1 μm to 60 μm. For example, the plurality of lens patterns L1 to Ln do not overlap and are connected to each other along at least one of the first direction X, the second direction Y, and the diagonal direction between the first direction X and the second direction Y, and therefore may have various diameters D1 to Dn in the range of 1 μm to 60 μm. For example, the refractive layer 411 composed of the plurality of lens patterns L1 to Ln may have a structure in which the plurality of lens patterns L1 to Ln having relatively small diameters are disposed between the plurality of lens patterns L1 to Ln having relatively large diameters or are filled between the plurality of lens patterns L1 to Ln having relatively large diameters.

[0162] Each of the plurality of lens patterns L1 to Ln may have a different height H1 to Hn. For example, each of the plurality of lens patterns L1 to Ln may have a different height H1 to Hn from the lower surface 400 b of the light guide member 400 .

[0163] Each of the plurality of lens patterns L1 to Ln may have a different height ratio H / D in the range of 20% to 50%. For example, the plurality of lens patterns L1 to Ln do not overlap and are connected to each other along at least one of the first direction X, the second direction Y, and a diagonal direction between the first direction X and the second direction Y, and thus may have various height ratios H / D in the range of 20% to 50%.

[0164] The light guide member 400 according to an embodiment of the present disclosure may include a plurality of blocks 400B.

[0165] The plurality of blocks 400B may be connected to each other along the first direction X and the second direction Y, respectively. For example, the plurality of lens patterns L1 to Ln in the light guide member 400 may be divided (or grouped) into the plurality of blocks 400B. Therefore, each of the plurality of blocks 400B may be a pattern block, a refraction pattern block, a guide pattern block, or a guide refraction pattern block.

[0166] The plurality of blocks 400B may have the same plurality of lens patterns L1 to Ln. For example, the plurality of lens patterns L1 to Ln in each of the plurality of blocks 400B may be arranged to have random intervals (or irregular intervals) along at least one of the first direction X, the second direction Y, and the diagonal direction between the first direction X and the second direction Y to reduce or suppress the appearance of rainbow moire and / or annular patterns and the appearance of moire phenomena. That is, the plurality of lens patterns L1 to Ln may have the same atypical arrangement structure in each of the plurality of blocks 400B. For example, the plurality of lens patterns L1 to Ln may have the same atypical arrangement structure in each of the plurality of blocks 400B. Therefore, the plurality of lens patterns L1 to Ln in each of the plurality of blocks 400B may be atypical block patterns, irregular block patterns, or irregular block patterns.

[0167] According to an embodiment of the present disclosure, by including the plurality of blocks 400B, a phenomenon in which flickering caused by an uneven contrast difference between a bright portion LP and a dark portion DP due to visual recognition of height differences caused by the plurality of lens patterns L1 to Ln arranged in atypical shapes can be suppressed.

[0168] At the same time, although not shown, Figure 3 , Figure 5 and Figure 6 In the embodiment of the present invention, the plurality of blocks 400B may be arranged only in the non-folding area (see Figure 3 NFA), while Figure 7 and Fig. 9 In the embodiment, it can be arranged in both the folding area and the non-folding area (see Figure 7 FA and NFA).

[0169] A plurality of blocks 400B may be connected to each other along each of the first direction X and the second direction Y. A plurality of lens patterns L1 to Ln may have the same atypical arrangement structure in each of the plurality of blocks 400B. For example, a plurality of lens patterns L1 to Ln may have the same atypical arrangement structure in each of the plurality of blocks 400B. Each of the plurality of blocks 400B may have a first size BL1 in a first direction (e.g., a horizontal direction) and may have a second size BL2 in a second direction (e.g., a vertical direction). In this case, each of the plurality of blocks 400B may have a first size BL1 or a second size BL2 greater than 87 μm and less than or equal to 800 mm.

[0170] As described above, the foldable display device according to another embodiment of the present disclosure may include a plurality of blocks 400B having an atypical arrangement structure and including a plurality of lens patterns L1 to Ln connected or spaced apart from each other, thereby improving black visibility characteristics by reflecting external light, achieving true black in a non-driven or off state, and further minimizing or reducing the moire phenomenon caused by interference between the lens pattern and the pixel and the flicker phenomenon caused by the contrast difference due to the lens pattern. Therefore, the foldable display device according to another embodiment of the present disclosure may have improved image quality and may further improve the viewer's visibility of the image.

[0171] Therefore, the present disclosure may have the following advantages.

[0172] According to an embodiment of the present disclosure, the light guiding member includes a plurality of atypical first lens patterns and includes a first filling layer having a refractive index different from that of the plurality of first lens patterns, thereby preventing rainbow moire or annular moire from occurring due to external light when the foldable display device is not driven.

[0173] According to an embodiment of the present disclosure, since an intermediate layer including a continuous area having the same modulus from top to bottom of the light guide member is provided in the folding area, lifting or peeling of the light guide member due to the modulus difference can be prevented or minimized even when the folding area is folded.

[0174] According to an embodiment of the present disclosure, since continuous regions having the same modulus from the upper surface to the lower surface of the light guide member are alternately disposed in the folded region, the folded region may be flat in an unfolded state without rising or curling.

[0175] According to an embodiment of the present disclosure, a plurality of first lens patterns and a first filling layer are arranged in a non-folding area, a plurality of second lens patterns are arranged on the lower surface of a light guide member in the folding area, a second filling layer having a refractive index different from that of the plurality of second lens patterns is arranged on the upper surface of the light guide member, and a modulus difference between the plurality of second lens patterns and the second filling layer in the folding area is formed to be smaller than a modulus difference between the plurality of first lens patterns and the first filling layer in the non-folding area, so that even if the folding area is folded, a lifting phenomenon or a peeling phenomenon in the light guide member can be prevented or minimized.

[0176] According to an embodiment of the present disclosure, since each of the plurality of blocks includes a plurality of lens patterns and a filling layer arranged in the same pattern, flickering caused by a contrast difference caused by different heights of the plurality of lens patterns atypically irregularly arranged can be suppressed.

[0177] It is obvious to those skilled in the art that various substitutions, modifications and variations are possible within the scope of the present disclosure without departing from the spirit and scope of the present disclosure. Therefore, the scope of the present disclosure is represented by the appended claims, and all changes or modifications derived from the meaning, scope and equivalent concepts of the claims should be interpreted as being included within the scope of the present disclosure.

Claims

1. A foldable display device, comprising: A display panel including a folding area and a non-folding area; and a light guide member, which is disposed on the display panel and includes the folding area and the non-folding area, Wherein, the light guide component comprises: A plurality of first lens patterns are arranged in the non-folding area, A first filling layer disposed in the non-folding area and disposed on the plurality of first lens patterns; and an intermediate layer disposed in the folded region, Wherein, the intermediate layer comprises: a first portion protruding from a lower surface of the light guide member; and a second portion recessed from the upper surface of the light guide member, A difference between a modulus of the first portion and a modulus of the second portion is smaller than a difference between a modulus of the plurality of first lens patterns and a modulus of the first filling layer.

2. The foldable display device according to claim 1, in, The modulus of the first portion and the modulus of the second portion are the same.

3. The foldable display device according to claim 1, The refractive index of the first portion and the refractive index of the second portion are different from each other.

4. The foldable display device according to claim 3, in, The convex surface of the first portion and the concave surface of the second portion correspond to each other.

5. The foldable display device according to claim 3, in, A difference between a refractive index of the plurality of first lens patterns and a refractive index of the first filling layer is the same as a difference between a refractive index of the first portion and a refractive index of the second portion. 6 . The foldable display device according to claim 1 , wherein a refractive index of the first lens pattern and a refractive index of the first filling layer are different from each other.

7. The foldable display device according to claim 1, wherein the first lens pattern is set in an atypical shape and irregular arrangement to diffract and / or scatter external light incident into the foldable display device from the outside based on the principle of light refraction with a refractive index difference. 8 . The foldable display device of claim 7 , wherein each of the first lens patterns is configured to have a hemispherical shape.

9. The foldable display device according to claim 8, wherein each of the plurality of first lens patterns includes a lower surface corresponding to a portion of the lower surface of the light guide member and a convex surface formed protruding from the lower surface, and at least a portion of the first filling layer has a concave surface corresponding to the convex surface.

10. The foldable display device according to claim 1, in, The folding area includes: a first region including a portion that is subjected to the greatest stress when the light guide member is folded; and a second region extending from one side of the first region to the unfolded region, The intermediate layer is arranged in the first region.

11. The foldable display device according to claim 10, wherein the second area of ​​the folding area includes a plurality of second lens patterns, And the second filling layer is disposed on the plurality of second lens patterns. 12 . The foldable display device of claim 11 , wherein the second lens patterns are provided in an irregular arrangement in an atypical shape. 13 . The foldable display device according to claim 11 , wherein a refractive index of the second lens pattern and a refractive index of the second filling layer are different from each other.

14. The foldable display device according to claim 11, The first filling layer is continuous with the second filling layer.

15. The foldable display device according to claim 11, Wherein at least some of the plurality of first lens patterns and the plurality of second lens patterns have different diameters or different pitches.

16. The foldable display device according to claim 15, in, Some of the plurality of first lens patterns and the plurality of second lens patterns are connected to each other.

17. A foldable display device, comprising: A display panel including a folding area and a non-folding area; and a light guide member, which is disposed on the display panel and includes the folding area and the non-folding area, Wherein, the light guide component comprises: A plurality of first lens patterns are arranged in the non-folding area, A first filling layer disposed in the non-folding area and disposed on the plurality of first lens patterns; and an intermediate layer disposed in the folded region, The intermediate layer includes a continuous region having the same modulus from the upper surface of the light guide member to the lower surface of the light guide member.

18. The foldable display device according to claim 17, in, The intermediate layer comprises: a third portion connected from the lower surface of the light guide member to the upper surface and a fourth portion connected from the lower surface of the light guide member to the upper surface, The third part and the fourth part are arranged alternately.

19. The foldable display device according to claim 18, The modulus of the third portion and the modulus of the fourth portion are different from each other.

20. The foldable display device according to claim 18, in, The cross section of the third portion is configured to be triangular.

21. The foldable display device according to claim 18, in, The cross section of the third portion is configured to be trapezoidal. 22 . The foldable display device of claim 17 , wherein a refractive index of the first lens pattern and a refractive index of the first filling layer are different from each other.

23. The foldable display device according to claim 17, wherein the first lens pattern is set in an atypical shape and irregular arrangement to diffract and / or scatter external light incident into the foldable display device from the outside based on a principle of light refraction with a refractive index difference. 24 . The foldable display device of claim 23 , wherein each of the first lens patterns is configured to have a hemispherical shape.

25. A foldable display device according to claim 24, wherein each of the plurality of first lens patterns includes a lower surface corresponding to a portion of the lower surface of the light guide member and a convex surface formed protruding from the lower surface, and at least a portion of the first filling layer has a concave surface corresponding to the convex surface.

26. The foldable display device according to claim 17, in, The folding area includes: a first region including a portion that is subjected to maximum stress when the light guide member is folded; and a second region extending from one side of the first region to the unfolded region, wherein the continuous region having the same modulus from the upper surface of the light guide member to the lower surface of the light guide member is provided in the first region.

27. The foldable display device according to claim 26, wherein the second area of ​​the folding area includes a plurality of second lens patterns, And the second filling layer is disposed on the plurality of second lens patterns.

28. The foldable display device of claim 27, wherein the second lens patterns are provided in an atypical shape and an irregular arrangement. 29 . The foldable display device of claim 27 , wherein a refractive index of the second lens pattern and a refractive index of the second filling layer are different from each other.

30. The foldable display device according to claim 27, Wherein at least some of the plurality of first lens patterns and the plurality of second lens patterns have different diameters or different pitches.

31. The foldable display device according to claim 30, in, Some of the plurality of first lens patterns and the plurality of second lens patterns are connected to each other.

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