DISPLAY DEVICE WITH OPTICAL ENHANCEMENT LAYER

Abstract

A display device is under discussion, comprising a display panel with pixels and an optical enhancement layer on the display panel. The optical enhancement layer contains a first pattern layer and a second pattern layer that overlap. The first pattern layer has a first refractive index, the second pattern layer has a second refractive index different from the first, the first pattern layer has an average pattern size larger than that of the second pattern layer, and the average pattern ratios of the patterns contained in the first pattern layer are smaller than the average pattern ratios of the patterns contained in the second pattern layer.

Description

This application claims priority over Korean patent application No. 10-2024-0200134, filed in the Republic of Korea on December 30, 2024. BACKGROUND Technical field The present disclosure relates to a display device which contains an optical enhancement layer and which can thereby prevent or suppress a sanding phenomenon caused by external light and a flickering phenomenon caused by an internal light source. Discussion of the related field Organic light-emitting diode (OLED) displays are attracting attention as the next generation of flat panel displays because, as self-illuminating devices that do not require a separate light source, OLED displays offer fast response times, low power consumption, and excellent viewing angles. Furthermore, OLED displays offer the advantage of being easily adaptable to flexible display configurations. The display device, which may contain the OLED display devices, can include a display panel on which images are shown. In addition, a translucent covering substrate is typically arranged on the surface of the display device's display panel. Furthermore, the covering substrate may be surface-treated to prevent glare. To prevent glare perceived by the covering substrate, irregular micropatterns may be formed on the substrate. When such irregular patterns are present, a flickering phenomenon can occur when the light-emitting element emits light, due to irregularity or inconsistency caused by the irregularly arranged patterns. The flickering phenomenon refers to a phenomenon in which bright and dark areas on the display device surface appear irregularly as points corresponding to the intervals between the patterns. Meanwhile, when light from outside the display device (external incident light) enters the display, reflection and refraction occur in each layer comprising the covering substrate and the display panel. Due to the fluctuations in the reflected or refracted light, a blurred area, resembling sand sprinkled upon it, can appear near the point where the reflected external light is detected. This phenomenon is known as the sand phenomenon. If the flickering or sanding phenomenon occurs, the display quality of the display device may deteriorate. Therefore, it is necessary or desirable to prevent or suppress the flickering or sanding phenomenon in the display device. SUMMARY OF THE REVELATION One objective of the present disclosure is to provide a display device that can effectively overcome the occurrence of a flickering phenomenon or a sanding phenomenon. One objective of the present disclosure is to provide a display device that can effectively suppress a flickering phenomenon that occurs when an internal light-emitting element emits light (in an ON state) and a sanding phenomenon that occurs when external light is reflected off a display device surface. One objective of the present disclosure is to provide a technology that can effectively overcome a flickering phenomenon or a sanding phenomenon in a display device. One embodiment of the present disclosure provides a display device that can prevent a flickering phenomenon or a sanding phenomenon. At least one of the tasks described above is solved by the features of the independent claims. Further developments are defined by the respective dependent claims. In one aspect of the present invention, a display device is provided comprising a display panel having pixels and an optical enhancement layer on the display panel, wherein the optical enhancement layer comprises a first pattern layer and a second pattern layer overlapping each other, the first pattern layer having a first refractive index, the second pattern layer having a second refractive index different from the first refractive index, the first pattern layer having a larger average pattern size than the second pattern layer, and the average pattern ratio of patterns contained in the first pattern layer being smaller than the average pattern ratio of patterns contained in the second pattern layer. The average pattern size is an average value of the maximum diameter of each pattern in a top-view image for each of the first pattern layer and the second pattern layer, wherein the pattern ratio is calculated as "b / a", where "a" denotes a maximum diameter of each pattern and "b" denotes a height of the pattern, and the average of the pattern ratio is calculated as an average value of the pattern ratio of the multiple patterns. In one aspect of the present invention, an optical enhancement layer is provided comprising a first pattern layer and a second pattern layer overlapping each other, wherein the first pattern layer has a first refractive index, the second pattern layer has a second refractive index different from the first refractive index, the first pattern layer has a larger average pattern size than the second pattern layer, and the average pattern ratio of patterns contained in the first pattern layer is smaller than the average pattern ratio of patterns contained in the second pattern layer.The average pattern size is an average value of the maximum diameter of each pattern in a top-view image for each of the first pattern layer and the second pattern layer, wherein the pattern ratio is calculated as "b / a", where "a" denotes a maximum diameter of each pattern and "b" denotes a height of the pattern, and the average of the pattern ratio is calculated as an average value of the pattern ratio of the multiple patterns. In one aspect of the present invention, a display device is provided comprising a display panel having pixels and an optical enhancement layer on the display panel. The optical enhancement layer includes a first pattern layer and a second pattern layer, wherein the first pattern layer has a first refractive index and first patterns with a first average pattern ratio, and the second pattern layer has a second refractive index and second patterns with a second average pattern ratio. The first average pattern ratio is smaller than the second average pattern ratio. Several second patterns overlap with a pattern of the first patterns. Each average pattern ratio of the respective first and second patterns is an average of "b / a", where "a" is a maximum diameter and "b" is a height of each pattern of the respective first and second patterns. The display device and / or the optical enhancement layer may include one or more of the following features: The first pattern layer can contain multiple lens patterns. The second pattern layer can contain multiple horn-shaped patterns. Each of the multiple patterns in the second pattern layer can have the shape of a horn. The lens patterns and / or the horn-shaped patterns can project in a direction perpendicular to the scoreboard, i.e., from a plane defined by the scoreboard. The first patterns can be or contain lens patterns. The second patterns can be or contain horn-shaped patterns. The optical enhancement layer may contain an intermediate layer on the first pattern layer. The intermediate layer can touch the first pattern layer. The first pattern layer and the intermediate layer can have a refractive index difference in the range of 0.05 to 0.1. The difference in refractive index between the first pattern layer and the intermediate layer can also be in the range of 0.05 to 0.1. The intermediate layer can touch the first pattern layer and / or the second pattern layer. The difference in refractive index between the intermediate layer and the second pattern layer can be 0.01 or less. The intermediate layer can contain the same material as the second pattern layer or be made from it. The intermediate layer can be formed in one piece with the second pattern layer. The first sample layer and the second sample layer can have a refractive index difference in the range of 0.05 to 0.1. The optical enhancement layer may contain a filler layer on the second pattern layer. The filler layer can touch the second pattern layer. The filler layer can be in surface contact with the second patterns of the second pattern layer. The second pattern layer and the filler layer can have a refractive index difference in the range of 0.05 to 0.1. The intermediate layer and / or the filler layer can be arranged between the first pattern layer and the second pattern layer. The intermediate layer and the filler layer can contain the same material or be made from it. The optical enhancement layer may contain a spacer positioned between the intermediate layer and the filler layer. The filler layer can be placed between the first pattern layer and the second pattern layer. The filler layer can be formed in one piece with the first pattern layer. The first pattern layer can touch the second pattern layer. The first and second pattern layers can be in surface contact. Projections of the first pattern layer and projections of the second pattern layer can protrude in opposite directions. The height of the first pattern layer can protrude in the opposite direction to the height of the second pattern layer. The term "protrusion" can refer to the pattern dimension "b". The first pattern layer and the second pattern layer can be formed in one piece. The difference in refractive index between the first pattern layer and the intermediate layer can be equal to the difference in refractive index between the second pattern layer and the filler layer. The display device may contain a covering substrate on the filler layer. The filler layer may have the same refractive index as the covering substrate. The display panel may contain a top layer. The first pattern layer may be arranged on the top layer. The top layer may have the same refractive index as the first pattern layer. The scoreboard may contain a color filter layer. The optical enhancement layer may be placed on top of the color filter layer. In one aspect of the present invention, a method for producing an optical enhancement layer for a display device is provided.The process comprises forming a first translucent resin layer on a support substrate; forming a first pattern layer by patterning on the first translucent resin layer using a first rolling element, wherein the first rolling element contains a plating layer having a hemispherical concave section; forming an intermediate layer on the first pattern layer; forming a second translucent resin layer on the intermediate layer; forming a second pattern layer by patterning on the second translucent resin layer using a second rolling element, wherein the second rolling element contains a sand-treated plating layer to include a concave section; forming a filler layer on the second pattern layer; and removing the support substrate.The concave section of the sand-treated plating layer can be horn-shaped to match the horn-shaped patterns of the second pattern layer. The hemispherical concave section of the plating layer of the first rolling element can match the lens patterns of the first pattern layer. By arranging or forming an optical enhancement layer, which has a first pattern layer and a second pattern layer with different pattern shapes, on a display panel, a flickering or sanding phenomenon in a display device can be effectively overcome. The optical enhancement layer can be configured to effectively suppress the flickering or sanding phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS The further tasks, features and other advantages of the present disclosure will be more clearly understood from the following detailed description in conjunction with the accompanying drawings; they show: Fig. 1 is a schematic diagram of a display device according to one embodiment of the present disclosure; Fig. 2 is a schematic diagram of an embodiment of a display panel; Fig. 3 is a top view of a structure of a pixel illustrated in Fig. 2; Fig. 4 is a cross-sectional view of a structure of a subpixel of Fig. 3; Fig. 5 is a partial cross-sectional view of an optical enhancement layer of Fig. 4; Fig. 6A is a top view of a first pattern layer and Fig. 6B is a top view of a second pattern layer; Fig. 7A and Fig. 7B are schematic diagrams illustrating the mechanism by which the flickering phenomenon is eliminated; Fig. 8A and Fig. 8B are schematic diagrams illustrating the mechanism by which the sanding phenomenon is eliminated; Fig. 9 is a partial cross-sectional view of a display device according to a further embodiment of the present disclosure; Fig. 10, Fig. 11, Fig. 12, Fig. 13, Fig. 14, Fig. 15 to Fig.16 partial cross-sectional views of the optical enhancement layers, each applied to a display device according to a further embodiment of the present disclosure; Fig. 17A a partial cross-sectional view of a display device according to Comparative Example 1 and Fig. 17B a partial cross-sectional view of a display device according to Comparative Example 2; Fig. 18 an image showing the elimination of a flickering phenomenon and a sanding phenomenon; Figs. 19A to 19H schematic cross-sectional views illustrating a method for producing an optical enhancement layer according to an embodiment of the present disclosure; Figs. 20A to 20C schematic perspective views illustrating a method for producing a first rolling element for forming a first pattern layer; and Fig.Figures 21A to 21C are schematic perspective views illustrating a method for manufacturing a second rolling element to form a second pattern layer. DETAILED DESCRIPTION OF THE EXECUTION FORM The advantages and features of the present disclosure and the methods for achieving them will become clearer with reference to the embodiments described in detail below, together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but can be implemented in several different forms. These embodiments are provided solely to ensure that the disclosure of the present disclosure is complete and to inform those skilled in the art of the scope of the invention. The shapes, sizes, ratios, angles, numbers, etc., disclosed in the drawings to illustrate embodiments of the present disclosure are merely illustrative, and the present disclosure is not limited to the details shown in the drawings. Throughout the disclosure, identical components may be designated by identical reference numerals. Furthermore, when describing the present disclosure, if a precise description of a related known technology is deemed to unnecessarily obscure the main content of the present disclosure, the precise description will be omitted. In this revelation, where the words "contain," "exhibit," and "consist of" are used, further parts may be added unless the expression "merely" is used. When a component is expressed in the singular, the plural is included unless clearly stated otherwise. When interpreting a component, it is interpreted as containing the error scope, even if no explicit separate description is provided. For example, if the positional relationship between two parts is described as "on~", "above~", "below~", "next to~", etc., one or more other parts may be arranged between the two parts unless the expression "exactly" or "directly" is used. Spatially relative terms such as "under," "below," "lower," "above," and "above" can be used to easily describe the relationship between an element or component and other elements or components, as illustrated in the drawings. Spatially relative terms should be understood to encompass various orientations of the elements during use or operation, in addition to the orientations shown in the drawings. For example, if an element shown in the drawings is inverted, an element described as "under" or "below" another element may then come to be "above" that other element. Thus, the exemplary term "under" can encompass both directions of under and above. Similarly, the exemplary term "above" can encompass both directions of above and under. When a temporal relationship is described, e.g., when temporal continuity is described as "after," "following," "next to," or "before," there may also be cases where it is not continuous, as long as the term "immediately" or "directly" is not used. While terms such as "first" and "second" are used to describe different components, these components are not limited by these terms. These terms are merely used to distinguish one component from another. Therefore, within the technical scope of this disclosure, a "first" component referred to as can also be a "second" component. The phrase "at least one" should be understood to include all possible combinations of one or more associated elements. For example, "at least one of the first, the second, and the third element" can mean not only the first, the second, or the third element, but also any combination of elements represented by two or more of the first, the second, and the third element. The features of each of the different embodiments of the present disclosure can be partially or completely combined or combined with one another, and various technical connections and operations are possible, and all embodiments can be implemented independently of one another or together in a related relationship. When adding reference numerals to components of each drawing that describes embodiments of the present disclosure, the same components may, where possible, have the same numerical symbols, even if they are shown in different drawings. Examples of the present disclosure are described below with reference to the accompanying drawings and examples. For the sake of clarity, the scales of the components illustrated in the drawings differ from the actual scale and are therefore not limited to those shown in the drawings. Fig. 1 is a schematic diagram of a display device 100 according to one embodiment of the present disclosure. All components of each display device according to all embodiments of the present disclosure are functionally coupled and configured. A display device 100 according to a further embodiment of the present disclosure can include a display panel 310, a gate driver 320, a data driver 330 and a control unit 340, as illustrated in Fig. 1. The gate lines GL and the data lines DL are arranged on the display panel 310, and pixels P are located at the intersections of the gate lines GL and the data lines DL. An image is displayed by addressing the pixels P. The control unit 340 controls the gate driver 320 and the data driver 330. The control unit 340 outputs a gate control signal (GCS) to control the gate driver 320 and a data control signal (DCS) to control the data driver 330 using a signal supplied by an external system. Additionally, the control unit 340 samples input image data from the external system, rearranges it, and supplies the rearranged RGB digital image data to the data driver 330. The gate control signal GCS contains a gate start pulse (GSP), a gate switching clock (GSC), a gate output activation signal (GOE), a start signal (Vst), and a gate clock (GCLK). Additionally, the gate control signal GCS can contain control signals for controlling a 350 shift register. The data control signal DCS contains a source start pulse (SSP), a source switching clock signal (SSC), a source output activation signal (SOE), and a polarity control signal (POL). The data driver 330 supplies a data voltage to the data lines DL of the display panel 310. Specifically, the data driver 330 converts image data (RGB) input by the control unit 340 into an analog data voltage and supplies this data voltage to the data lines DL. The gate driver 320 can contain a shift register 350. The shift register 350 sequentially feeds gate pulses to the gate lines GL for a frame, using a start signal and a gate clock transmitted by the control unit 340. Here, a frame refers to a period of time during which an image is displayed by the display panel 310. The gate pulse has a turn-on voltage that can switch on a switching element (a thin-film transistor) located in a pixel P. Additionally, the shift register 350 feeds a gate-off signal, which can switch off the switching element, to the gate line GL during the remaining period in which no gate pulse is supplied during a frame. Hereinafter, the gate pulse and the gate-off signal are collectively referred to as a scan signal (SS or scan). According to one embodiment of the present disclosure, the gate driver 320 can be mounted on the display panel 310. In this way, a structure in which the gate driver 320 is directly mounted on the display panel 310 is referred to as a gate-in-panel (GIP) structure. The gate driver 320 can contain multiple thin-film transistors. These multiple thin-film transistors can be arranged in a shift register 350. Fig. 2 is a schematic diagram of an embodiment of a display panel 310. Fig. 2 illustrates an organic light-emitting panel as an example of a display panel 310 applied to a display device 100. The display device 100 of Fig. 1, which contains an organic light-emitting panel, can be referred to as an organic light-emitting display device. Referring to Fig. 2, the display panel 310 contains a substrate 110 and pixels P on the substrate 110. The glass substrate or a plastic substrate can be used as substrate 110. Substrate 110 can contain a display area AA and a non-display area IA. The display area AA is the area in which an image is displayed and can be referred to as a pixel array area, an active area, a pixel array unit, a display unit, or a screen. The display area AA contains multiple pixels P. Several pixels P can be arranged in a first direction X and a second direction Y that intersects the first direction X. For example, the first direction X can be referred to as a first longitudinal direction, a long-side longitudinal direction, a horizontal direction, or a first horizontal direction of substrate 110. Additionally, the second direction Y can be referred to as a second longitudinal direction, a short-side longitudinal direction, a vertical direction, a second horizontal direction, or a vertical direction of substrate 110. Each of the multiple pixels P can be a unit area in which light is actually emitted. For example, the multiple pixels P can be arranged such that they have a pixel spacing (PP; see Fig. 3) in the first direction X. For example, the pixel spacing PP can be defined as the size of each of the multiple pixels P with respect to the first direction X, the distance between one side of each of two adjacent pixels P in the first direction X, or the distance between the centers of two adjacent pixels P in the first direction X. Each of the multiple pixels P can contain multiple adjacent subpixels SP. For example, multiple subpixels SP can form a single pixel P. The non-display area IA is an area in which no image is displayed. The non-display area IA can contain at least one peripheral circuit area, a signal input area, an inactive area, and a border area. The non-display area IA can also be referred to, for example, as a peripheral circuit area, a signal input area, an inactive area, or a border area. The non-display area IA can be configured to surround the display area AA. The display panel 310 can include a gate driver 320 located on the non-display area IA of the substrate 110. The gate driver 320 can also be referred to as a peripheral circuit. The gate driver 320 can be located on either side of the substrate 110. Fig. 3 is a top view of the structure of pixel P, which is illustrated in Fig. 2. In Fig. 2 and Fig. 3, the X-axis is the horizontal direction of the drawing, the Y-axis is the vertical direction of the drawing, and the Z-axis is the thickness direction. Referring to Fig. 2 and Fig. 3, in the display panel 310 of the display device 100 according to an embodiment of the present disclosure, each of the several pixels P can contain, for example, four subpixels SP1, SP2, SP3, SP4, however, embodiments of the present disclosure are not limited to this and a different number of subpixels can be used. In one embodiment of the present disclosure, a pixel P can contain a first, a second, a third, and a fourth subpixel SP1, SP2, SP3, SP4, which are adjacent to each other in a first direction X. For example, each of the multiple pixels P can contain a first red subpixel SP1, a second white subpixel SP2, a third green subpixel SP3, and a fourth blue subpixel SP4, but embodiments of the present disclosure are not limited thereto. According to one embodiment of the present disclosure, each of the first to fourth subpixels SP1 to SP4 can be configured to have different sizes or areas. Each of the first, second, third and fourth subpixels SP1, SP2, SP3, SP4 can contain an emission surface EA and a circuit surface CA. The emission surface EA can be located on one side of the subpixel surface, e.g., on the top side. The emission surface EA of each of the first, second, third, and fourth subpixels SP1, SP2, SP3, SP4 can have different sizes or areas. According to one embodiment of the present disclosure, the emission surface EA can also be referred to as an aperture surface or a light-emitting surface. According to one embodiment of the present disclosure, among the emission areas EA of each of the first, second, third, and fourth subpixels SP1, SP2, SP3, and SP4, the emission area EA of the second subpixel SP2 may be the largest, and the emission area EA of the fourth subpixel SP4 may be the smallest. The emission area EA of the first subpixel SP1 may be smaller than the emission area EA of the second subpixel SP2 and may be larger than the emission areas EA of each of the third and fourth subpixels SP3 and SP4. Additionally, the emission area EA of the third subpixel SP3 may be larger than the emission area EA of the fourth subpixel SP4. However, one embodiment of the present disclosure is not limited to these. According to one embodiment of the present disclosure, in each of the first, second, third, and fourth subpixels SP1, SP2, SP3, SP4, the circuit surface CA can be spatially separated from the emission surface EA. For example, the circuit surface CA can be located on the far side or the underside of the subpixel surface. For example, the circuit surface CA can be a non-light-emitting surface or a non-opening surface. However, one embodiment of the present disclosure is not limited to this. At least one section of the circuit surface CA can overlap with the emission surface EA. For example, in each of the subpixels SP1, SP2, SP3, SP4, the circuit surface CA can overlap with the entire emission surface EA or be located below the emission surface EA. According to one embodiment of the present disclosure, the emission surface EA can extend above the circuit surface CA, and the entire circuit surface CA can overlap with the emission surface EA. Each of the multiple pixels P can further include a light-transmitting surface arranged around at least one of the emission surface EA and circuit surface CA of each of the first, second, third, and fourth subpixels SP1, SP2, SP3, and SP4. For example, each of the multiple pixels P can include a pixel-specific emission surface EA corresponding to each of the multiple subpixels SP1 to SP4 and a light-transmitting surface arranged around each of the multiple subpixels SP1 to SP4. In this case, the display device 100 can implement a transparent display device due to light transmission through the light-transmitting surface. A transparent display device that includes an organic light-emitting panel can be referred to as a transparent organic light-emitting display device. Referring to Fig. 3, two data lines DL, running in the second direction Y, can be arranged parallel to each other between the first subpixel SP1 and the second subpixel SP2, and between the third subpixel SP3 and the fourth subpixel SP4. A gate line GL, running in the first direction X, can be arranged between the emission surface EA and the circuit surface CA of each of the first to fourth subpixels SP1 to SP4. A pixel power supply line PL, running in the second direction Y, can be arranged on one side of the first subpixel SP1 or the fourth subpixel SP4. A reference line RL, running in the second direction Y, can be arranged between the second subpixel SP2 and the third subpixel SP3.The reference line RL can be used as a sensing line for externally sensing a change in the properties of a drive thin-film transistor arranged in a circuit area CA, and / or a change in the properties of a layer of light-emitting elements when the pixel P is in sensing drive mode. Fig. 4 is a cross-sectional view of the structure of a subpixel SP of Fig. 3 . Referring to Fig. 3 and Fig. 4, a display device 100 according to an embodiment of the present disclosure comprises a display panel 310 containing pixels P, and an optical enhancement layer 210 on the display panel 310. The display panel 310 may comprise a substrate 110, a pixel circuit layer PCL, an organic light-emitting element 160, and an encapsulation layer 180. The substrate 110 can also be referred to as a first substrate, a base substrate, a lower substrate, a glass substrate, a plastic substrate, or a base element. According to one embodiment of the present disclosure, glass or plastic can be used as the substrate 110. A transparent plastic that has a flexible property, such as polyimide, can be used as the plastic. If polyimide is used as the substrate 110, and considering that a high-temperature deposition process is carried out on the substrate 110, a heat-resistant polyimide that can withstand high temperatures can be used. A pixel circuit layer PCL can be arranged on a substrate 110. The pixel circuit layer PCL can contain a buffer layer 112, a pixel circuit, and a protective layer 118. The buffer layer 112 can be arranged on the first surface or the entire top surface of the substrate 110. The buffer layer 112 can serve to block the diffusion of a material contained in the substrate 110 into the transistor layer during a high-temperature process in the thin-film transistor manufacturing process, or it can serve to prevent external moisture or atmospheric humidity from penetrating to the organic light-emitting element 160. Optionally, the buffer layer 112 can be omitted. The pixel circuit can include a driver thin-film transistor Tdr, which is arranged in a circuit area CA of each subpixel SP. The driver thin-film transistor Tdr can include an active layer 113, a gate insulating layer 114, a gate electrode 115, an insulating intermediate layer 116, a drain electrode 117a, and a source electrode 117b. The active layer 113 can comprise a semiconductor material based on any amorphous silicon, polycrystalline silicon, oxide, or organic material. The active layer 113 can include a channel region 113c, a drain region 113d, and a source region 113s. The gate isolation layer 114 can be arranged on the active layer 113. The gate isolation layer 114 can be arranged in an island shape only on the channel part 113c of the active layer 113, or it can be arranged on the entire upper surface of the substrate 110 or the buffer layer 112 containing the active layer 113. The gate electrode 115 can be arranged on the gate insulation layer 114 to overlap with the channel part 113c of the active layer 113. An insulating layer 116 can be formed on the gate electrode 115 and the drain region 113d and the source region 113s of the active layer 113. The insulating layer 116 can be formed on the entire upper surface of the substrate 110 or the buffer layer 112. For example, the insulating layer 116 can be made of an inorganic or an organic material. The drain electrode 117a can be arranged on the insulating intermediate layer 116 to be electrically connected to the drain region 113d of the active layer 113. The source electrode 117b can be arranged on the insulating intermediate layer 116 to be electrically connected to the source region 113s of the active layer 113. The pixel circuit can further include at least one capacitor arranged in a circuit area CA together with a control thin-film transistor Tdr, and at least one switching thin-film transistor. The display device 100 according to one embodiment of the present disclosure may further include a light-shielding layer 111. The light-shielding layer 111 may be arranged on the substrate 110 to overlap with the active layer 113 and may be configured to minimize or prevent a change in the threshold voltage of the thin-film transistor due to external light. According to the present disclosure, the light-shielding layer 111 may be arranged beneath the active layer 113 of the driver thin-film transistor Tdr or the switching thin-film transistor. A protective layer 118 can be arranged over the pixel circuit. For example, the protective layer 118 can be configured to surround the drain electrode 117a and the source electrode 117b of the driving thin-film transistor Tdr and the insulating intermediate layer 116. For example, the protective layer 118 can be formed from an inorganic insulating material. The protective layer 118 can also be referred to as a passivation layer or an insulating intermediate layer. The planarization layer 130 can be located on the pixel circuit layer PCL. The planarization layer 130 can encompass the entire display area AA and the remaining area of ​​the non-display area IA, excluding the contact area. For example, the planarization layer 130 can include an extension section that runs from the display area AA to the remaining non-display area IA, excluding the contact area. Accordingly, the planarization layer 130 can have a size that is relatively larger than the display area AA. According to one embodiment of the present disclosure, the planarization layer 130 can be formed such that it has a relatively thick profile in order to provide a flat surface 130a on the pixel circuit layer PCL. For example, the planarization layer 130 can be made of an organic material. An organic light-emitting element 160 can be arranged in an emission surface EA of each subpixel SP. According to one embodiment of the present disclosure, the organic light-emitting element 160 can comprise a first electrode E1, an emission layer EL, and a second electrode E2. According to one embodiment of the present disclosure, the first electrode E1, the light-emitting layer EL and the second electrode E2 can be configured to emit light to the opposite side of the substrate 110 according to a top-emitting method, or can be configured to emit light to the substrate 110 according to a bottom-emitting method. In the following, embodiments of the present disclosure are described with a focus on a display device 100 which includes an organic light-emitting element 160 configured to emit light to the opposite side of a substrate 110 according to a top-emitting method. The first electrode E1 can be formed on a planarization layer 130 of a subpixel surface SPA and can be electrically connected to a source electrode 117b of a driver thin-film transistor Tdr. One end of the first electrode E1, adjacent to the circuit surface CA, can be electrically connected to a source electrode 117b of the driver thin-film transistor Tdr through an electrode contact hole CH provided in the planarization layer 130 and the protection layer 118. The light-emitting layer EL can be formed on the first electrode E1 and can directly touch the first electrode E1. According to one embodiment of the present disclosure, the light-emitting layer EL can contain two or more organic light-emitting layers for emitting white light. For example, the light-emitting layer EL can contain a first organic light-emitting layer and a second organic light-emitting layer for emitting white light by mixing a first light and a second light. The second electrode E2 is positioned on the light-emitting layer EL and can directly contact it. The second electrode E2 can have a relatively small thickness compared to the light-emitting layer EL. According to one embodiment of the present disclosure, for upward emission, the first electrode E1 can have a structure capable of reflecting light emitted from the light-emitting layer EL and incident on the first electrode E1 to the opposite side of the substrate 110. To reflect light emitted from and incident on the light-emitting layer EL to the opposite side of the substrate 110, the first electrode E1 can contain a metallic material exhibiting high reflectivity. For example, the first electrode E1 can have a single-layer structure or a multi-layer structure made of a material selected from aluminum (Al), silver (Ag), molybdenum (Mo), gold (Au), magnesium (Mg), calcium (Ca), or barium (Ba), or an alloy of two or more materials; however, embodiments of the present disclosure are not limited thereto.The first electrode E1 can be an anode electrode. The second electrode E2 can have either transparency or transmittance. In one embodiment of the present disclosure, transparency can be referred to as transmittance. According to one embodiment of the present disclosure, the second electrode E2 can have both transmittance and reflection properties. The second electrode E2 can have a multilayer structure, including, for example, a layer made of a transparent conductive oxide (TCO) and a layer made of a metal with a low work function; however, embodiments of the present disclosure are not limited to such multilayer structures. The second electrode E2 can be a cathode electrode. The display device 100 according to an embodiment of the present disclosure can further comprise a bank layer 170. The bank layer 170 can be arranged on the edge of the first electrode E1 and the planarization layer 130. The bank layer 170 can be made of a transparent or an opaque material. For example, the bank layer 170 can be a transparent bank layer or a black bank layer. For example, the bank layer 170 can contain a black pigment, in which case the bank layer 170 can also act as an opaque element between adjacent subpixels SP. The encapsulation layer 180 can be formed on the substrate 110 to surround the organic light-emitting element 160. The encapsulation layer 180 can be arranged on the second electrode E2. For example, the encapsulation layer 180 can surround the display area AA. The encapsulation layer 180 can protect the thin-film transistor and the light-emitting layer EL from external influences and can serve to prevent oxygen, moisture, or foreign matter from penetrating the light-emitting layer EL. According to one embodiment of the present disclosure, the encapsulation layer 180 can contain several inorganic encapsulation layers. The encapsulation layer 180 can further contain at least one organic encapsulation layer arranged between the several inorganic encapsulation layers. The display device 100 according to one embodiment of the present disclosure may further include a color filter layer 150. The color filter layer 150 may be arranged in a direction in which light is emitted by the organic light-emitting element 160. According to one embodiment of the present disclosure, the color filter layer 150 may be arranged on the opposite side of the substrate 110 with the organic light-emitting element 160 as its center. The color filter layer 150 can be arranged on the organic light-emitting element 160 to overlap with at least one emission surface EA. According to one embodiment of the present disclosure, the color filter layer 150 can be arranged on the encapsulation layer 180. The color filter layer 150 can have a size that is wider than the emission area EA. For example, an edge section of the color filter layer 150 can overlap with the bank layer 170. According to one embodiment of the present disclosure, the color filter layer 150 can have a size that corresponds to the entire subpixel area SPA of each subpixel SP, thereby reducing light leakage between adjacent subpixels SP. According to one embodiment of the present disclosure, the color filter layer 150 can be configured to transmit a wavelength of a color set in the subpixel SP. For example, as illustrated in Fig. 3, if a pixel P contains a first, second, third, and fourth subpixel SP1, SP2, SP3, SP4, the color filter layer 150 can contain a red color filter provided in the first subpixel SP1, a green color filter provided in the third subpixel SP3, and a blue color filter provided in the fourth subpixel SP4. The second subpixel SP2 need not contain a color filter layer or may contain a transparent material for step compensation, thereby emitting white light. According to the present disclosure, the color filter layer 150 can be formed on the upper surface of the encapsulation layer 180 to overlap with the emission surface EA. For example, the color filter layer 150 can touch the upper surface of the encapsulation layer 180. However, an embodiment of the present disclosure is not limited to this, and a transparent adhesive element can be arranged between the encapsulation layer 180 and the color filter layer 150. The display device 100 according to an embodiment of the present disclosure may further include a black matrix 155 arranged between color filters of a color filter layer 150. The black matrix 155 can be arranged such that it overlaps with the remaining area excluding the emission surface EA of each subpixel SP. However, one embodiment of the present disclosure is not limited thereto, and the remaining area excluding the emission surface EA of each subpixel SP can contain a stacked structure of two or more color filters instead of the black matrix 155. For example, the remaining area excluding the emission surface EA of each subpixel SP can contain a stacked structure of two or more color filters beneath a red color filter, a green color filter, and a blue color filter. The stacked structure of two or more color filters can prevent color mixing between adjacent subpixels SP instead of the black matrix 155. Referring to Fig. 4, a top layer 185 can be arranged on the color filter layer 150. The top layer 185 can protect the color filter layer 150 and flatten the upper section of the color filter layer 150. The top layer 185 can also be referred to as a protective layer. The top layer 185 can also be omitted. According to one embodiment of the present disclosure, the laminate from the substrate 110 to the color filter layer 150 is referred to as a display panel 310. With reference to Fig. 4, the laminate from the substrate 110 to the top layer 185 can also be referred to as a display panel 310. The display device 100 according to one embodiment of the present disclosure includes the optical enhancement layer 210, which is arranged on a display panel 310. A first adhesive element 190 can be arranged between the display panel 310 and the optical enhancement layer 210. The optical enhancement layer 210 can be applied to and secured on the display panel 310 by the first adhesive element 190. Referring to Fig. 4, the display device 100 can include a cover substrate 250. An optical enhancement layer 210 can be arranged between the display panel 310 and the cover substrate 250. Additionally, a second adhesive element 290 can be arranged between the optical enhancement layer 210 and the cover substrate 250. The optical enhancement layer 210 can be attached and secured to the cover substrate 250 by the second adhesive element 290. The cover substrate 250 can be made of glass or a transparent plastic substrate. The light generated by the organic light-emitting element 160 of the display panel 310 can be emitted to the outside through the cover substrate 250. Additionally, external light can enter and be reflected by the cover substrate 250. When external light is reflected from the cover substrate 250, glare occurs on the cover substrate 250, and an image reflected from the cover substrate 250 may become visible to the user. To prevent such glare and the perception of the reflected image, the cover substrate 250 can be subjected to an anti-glare or matting treatment. The anti-glare or matting treatment for the cover substrate 250 may, for example, involve creating a fine pattern on the cover substrate 250 or performing a roughening treatment. The fine pattern or roughness treatment pattern formed on the cover substrate 250 is a random pattern. However, due to the irregularity or inconsistency of the multiple randomly arranged patterns, a sparkle or sanding phenomenon may occur. The flicker phenomenon refers to a phenomenon in which bright and dark areas are perceived irregularly as dots on a display device surface, corresponding to the intervals between patterns. This flicker phenomenon is particularly noticeable in a display device 100 containing a self-illuminating light-emitting element. For example, in a display panel 310 containing an organic light-emitting element 160, which is a self-illuminating display element, when light generated by the organic light-emitting element 160 is emitted outwards through the display panel 310 and the covering substrate 250, bright and dark areas can be perceived irregularly as small bubbles on the display device surface, corresponding to the intervals between several randomly arranged patterns.This phenomenon, in which shapes like small bubbles are perceived irregularly, is called a twinkling phenomenon. Meanwhile, the display device 100 has a structure in which several layers, each with different functions, are laminated. When light from the outside of the display device 100 (external incident light) enters it, reflection and refraction occur in each layer, forming the cover substrate 250 and the display panel 310. Due to the fluctuations in the light being reflected or refracted under different conditions, a blurred area resembling sand can be observed, scattered onto the surface near the point where the reflected external light is detected. This phenomenon, in which a blurred area is observed near the point where the reflected external light is detected, is known as the sand phenomenon. In order to prevent or suppress the occurrence of a flickering phenomenon or a sanding phenomenon in a display device 100, an optical enhancement layer 210 is arranged on a display panel 310 according to an embodiment of the present disclosure. Fig. 5 is a partial cross-sectional view of the optical enhancement layer 210 from Fig. 4. The optical enhancement layer 210 contains a first pattern layer 211 and a second pattern layer 212. The first pattern layer 211 and the second pattern layer 212 overlap. The first pattern layer 211 has a first refractive index, and the second pattern layer 212 has a second refractive index that differs from the first refractive index. The first sample layer 211 and the second sample layer 212 can each be made of a translucent resin. The translucent resin can also be described as a transparent resin. According to one embodiment of the present disclosure, a translucent resin can be formed by polymerizing a monomer. Light can be emitted (photopolymerization) or heat can be applied (thermal polymerization) to polymerize the monomer. For example, UV light can be used for photopolymerization. Additionally, to form a translucent resin, curing can be carried out after polymerization of the monomer. The curing methods include light curing and thermal curing. According to one embodiment of the present disclosure, the translucent resin can be formed by UV light curing using UV light. The translucent resin may contain at least one of the following polymer resins: polymethyl methacrylate-based (PMMA-based), polycarbonate-based (PC-based), polyethylene terephthalate-based (PET-based), polyurethane-based (PU-based), and polystyrene-based (PS-based), but embodiments of the present disclosure are not limited thereto. The first sample layer 211 and the second sample layer 212 can be made from materials of the same series or from different series. Even if the first sample layer 211 and the second sample layer 212 are made from materials of the same series, the first sample layer 211 and the second sample layer 212 can have different refractive indices if the curing conditions are different. The first sample layer 211 and the second sample layer 212 can each independently have a refractive index in the range of, for example, 1.4 to 2.0. Depending on the type of material forming the light-transmitting resin and the curing conditions, the refractive indices of the first sample layer 211 and the second sample layer 212 can each be set independently. Referring to Fig. 4, an intermediate layer 214 can be arranged on the first pattern layer 211. The intermediate layer 214 can have a refractive index different from that of the first pattern layer 211. The light can be refracted at the interface between the first pattern layer 211 and the intermediate layer 214 due to the difference in refractive index between the first pattern layer 211 and the intermediate layer 214. Referring to Fig. 4, a filler layer 213 can be arranged on the second pattern layer 212. The upper section of the second pattern layer 212 can be flattened by the filler layer 213. The filler layer 213 can be arranged between the patterns HP contained in the second pattern layer 212. The filler layer 213 and the intermediate layer 214 can each be made of a translucent resin. The translucent resin can contain at least one of the following polymer resins: polymethyl methacrylate-based (PMMA-based), polycarbonate-based (PC-based), polyethylene terephthalate-based (PET-based), polyurethane-based (PU-based), and polystyrene-based (PS-based), but embodiments of the present disclosure are not limited thereto. The filler layer 213 and the intermediate layer 214 can each independently have a refractive index in the range of, for example, 1.4 to 2.0. Depending on the type of material forming the light-transmitting resin and the curing conditions, the refractive indices of the filler layer 213 and the intermediate layer 214 can each be set independently; however, embodiments of the present disclosure are not limited to this. According to one embodiment of the present disclosure, as illustrated in Figs. 4 and 5, the first pattern layer 211 can have several lens patterns LS. Specifically, the first pattern layer 211 can contain several patterns having a lens shape. Hereinafter, the patterns having a lens shape are referred to as lens patterns LS. In embodiments of the present disclosure, the several lens patterns LS can have one or more vertices. One or more of the vertices can be rounded or curved. In this respect, viewed in cross-section, the several lens patterns LS can have curved or convex profiles. Each of the multiple lens patterns LS contained in the first pattern layer 211 can have a different size. The first pattern layer 211 can be formed by arranging multiple lens patterns LS that do not have uniform sizes on a single plane. The first pattern layer 211 can have an average pattern size in the range of 20 to 50 µm. The average pattern size can be defined as the average size of several lens patterns LS contained in the first pattern layer 211. According to one embodiment of the present disclosure, in a planar image of the first pattern layer 211, the maximum diameter of each of several patterns is measured, an average of these is calculated, and the average value can be referred to as an average pattern size. Similarly, the average pattern size can be referred to as an average value of the maximum diameter of each of the several patterns in the planar image of the first pattern layer 211. Fig. 6A is a top view of the first pattern layer 211. In Fig. 6A, each lens pattern LS can be defined by the pattern boundaries. Additionally, as illustrated in Fig. 6A, the maximum diameter a for each of the multiple patterns can be defined as the maximum length in each lens pattern LS displayed in a plane. The average pattern size of the first pattern layer 211 can be the average size of the multiple lens patterns LS contained in the first pattern layer 211. If the first pattern layer 211 has an average pattern size in the range of 20 to 50 µm, the phenomenon of a murasion visible due to external light can be effectively prevented or suppressed. When external light is incident on and reflected from the display device 10, coherence may occur due to diffraction by elements forming the display device 100, resulting in a rainbow dot pattern or an annular pattern. Such a pattern is called mura. Mura may also be referred to as reflection diffraction mura, rainbow mura, or the like. According to one embodiment of the present disclosure, mura can be prevented or suppressed by the first pattern layer 211, which contains several lens patterns LS having an average pattern size in the range of 20 to 50 µm. Specifically, the first pattern layer 211 can have an average pattern size in the range of 30 to 40 µm and can also have an average pattern size of about 35 µm. According to one embodiment of the present disclosure, the first pattern layer 211 can have an arithmetic mean roughness (Ra) in the range of 1.7 to 3.7 µm. The arithmetic mean roughness (Ra) can be measured using a surface roughness measuring device in accordance with JIS (Japanese Industrial Standard) B 0601. Specifically, the first sample layer 211 can have an arithmetic mean roughness (Ra) in the range of 2.0 to 3.5 µm, can have an arithmetic mean roughness (Ra) in the range of 2.5 to 3.0 µm, and can have an arithmetic mean roughness (Ra) of approximately 2.7 µm. Additionally, the first sample layer 211 can have an average width (Rsm) in the range of 130 to 170 µm. The average width (Rsm) can be defined as an average value for the distances between profile elements within a sample length. The average width (Rsm) can be measured using a surface roughness measuring device according to JIS B 0601. Since the average width (Rsm) is an average width within a sample length, it can differ from the size of an individual sample. Specifically, the first pattern layer 211 can have an average width (Rsm) in the range of 140 to 160 µm, an average width (Rsm) in the range of 145 to 155 µm, or an average width (Rsm) in the range of 150 to 153 µm. According to one embodiment of the present disclosure, a first pattern layer 211, having an average pattern size in the range of 20 to 50 µm, an arithmetic mean roughness (Ra) in the range of 1.7 to 3.7 µm and an average width (Rsm) in the range of 130 to 170 µm, is laminated with a second pattern layer 212, thereby preventing or suppressing a flickering phenomenon and a sanding phenomenon that occur in a display device 100. According to one embodiment of the present disclosure, a second pattern layer 212 can be arranged on a first pattern layer 211. The second pattern layer 212 can contain several patterns HP having a horn-shaped form. The patterns HP contained in the second pattern layer 212 can have a pronounced protrusion. In embodiments of the present disclosure, the several patterns HP can have one or more vertices. One or more of the vertices can be clear or pointed. In this respect, viewed in cross-section, the several patterns HP can have jagged and / or irregular profiles. Each of the multiple patterns HP contained in the second pattern layer 212 can have a different size. The second pattern layer 212 can be formed by arranging several horn-shaped patterns HP of non-uniform sizes in a single plane. According to one embodiment of the present disclosure, the second pattern layer 212 has a smaller average pattern size than the first pattern layer 211. The second pattern layer 212 can have an average pattern size, for example, in the range of 2 to 5 µm. The average pattern size of the second pattern layer 212 can be defined as an average value of the maximum diameter of each of the multiple patterns HP in a planar image of the second pattern layer 212; however, embodiments of the present disclosure are not limited thereto. Fig. 6B is a top view of the second pattern layer 212. In Fig. 6B, each horn-shaped pattern HP can be defined by the pattern boundaries. Additionally, as illustrated in Fig. 6B, the maximum diameter (a) for each of the multiple patterns can be defined as the maximum length in each pattern HP shown in the plane. Specifically, the second pattern layer 212 can have an average pattern size in the range of 3 to 4 µm and can also have an average pattern size of about 3.5 µm. According to one embodiment of the present disclosure, the second pattern layer 212 can have an arithmetic mean roughness (Ra) in the range of 0.4 to 0.7 µm. The arithmetic mean roughness (Ra) can be measured using a surface roughness measuring device in accordance with JIS (Japanese Industrial Standard) B 0601. Specifically, the second sample layer 212 can have an arithmetic mean roughness (Ra) in the range of 0.5 to 0.6 µm and can also have an arithmetic mean roughness (Ra) of approximately 0.53 µm. According to one embodiment of the present disclosure, the second pattern layer 212 can have an average width (Rsm) in the range of 60 to 100 µm. The average width (Rsm) can be measured using a surface roughness measuring device in accordance with standard JIS B 0601. Specifically, the second pattern layer 212 can have an average width (Rsm) in the range of 70 to 90 µm, an average width (Rsm) in the range of 75 to 85 µm, or an average width (Rsm) of approximately 80 µm. Additionally, the average pattern ratio (the first average pattern ratio) of the patterns contained in the first pattern layer 211 is smaller than the average pattern ratio (the second average pattern ratio) of the patterns contained in the second pattern layer 212. Here, the average pattern size, as described above, is the average value of the maximum diameter of each of the multiple patterns in the planar images for each of the first pattern layer 211 and the second pattern layer 212. Additionally, the pattern ratio is calculated as "b / a" where the maximum diameter of each pattern is "a" and the height is "b". The average pattern ratio is calculated as the average value of the pattern ratio for the multiple patterns. In various embodiments of the present disclosure, the pattern ratio b / a of the first pattern layer 211 may be less than or equal to 1.0, where b is less than or equal to a; however, embodiments of the present disclosure are not limited thereto, and the pattern ratio b / a of the first pattern layer may be greater than 1.0, where b is greater than a.Furthermore, in various embodiments of the present disclosure, the pattern ratio b / a of the second pattern layer 212 can be greater than or equal to 1.0, where b is greater than or equal to b; however, embodiments of the present disclosure are not limited thereto and the pattern ratio b / a of the second pattern layer can be less than 1.0, where b is less than a. According to one embodiment of the present disclosure, if the first pattern layer 211 and the second pattern layer 212 are laminated in an overlapping manner, the first pattern layer 211 has a larger average pattern size than the second pattern layer 212, and the average pattern ratio of the patterns contained in the first pattern layer 211 is smaller than the average pattern ratio of the patterns contained in the second pattern layer 212, a flickering phenomenon and a sanding phenomenon occurring in the display device 100 can be prevented or suppressed. Referring to Fig. 5, Fig. 6A, and Fig. 6B, for example, the heights of the multiple patterns HP contained in the second pattern layer 212 can generally vary or be irregular relative to one another, such that the heights of some of the multiple patterns HP are in the range of about 0.5 times to about 5 times or more greater than those of the other multiple patterns HP, if a variance exists. Furthermore, the diameters of the multiple patterns HP contained in the second pattern layer 212 can generally vary in their dimensions or sizes, such that the diameters of some of the multiple patterns HP are in the range of about 0.5 times to about 5 times or more greater than those of the other multiple patterns HP, if a variance exists; however, embodiments of the present disclosure are not limited thereto. Furthermore, the heights of the multiple lens patterns LS contained in the first pattern layer 211 can generally be similar or regular to one another, such that the heights of some of the multiple lens patterns LS are equal to or similar to those of the others of the multiple lens patterns LS, or vary by about 0.4 times or less if any variance exists. Additionally, the diameters of the multiple lens patterns LS contained in the first pattern layer 211 can be similar to or equal to each other, such that the diameters of some of the multiple lens patterns LS are approximately 0.4 times or less larger than those of the others of the multiple lens patterns LS if any variance exists; however, embodiments of the present disclosure are not limited thereto. With further reference to Fig. 6A, the multiple lens patterns LS contained in the first pattern layer 211 can touch each other and, in a top view, form a polygon shape at their bases. In various embodiments of the present disclosure, the bases of the multiple lens patterns LS can form a hexagonal pattern. Furthermore, with reference to Fig. 6B, the multiple patterns HP contained in the second pattern layer 212 can touch each other in a top view and form interstitial patterns, wherein the multiple patterns HP having comparatively smaller diameters are located in an interstitial manner between the multiple patterns HP having comparatively larger diameters. Additionally, with reference to Fig. 5, Fig. 6A, and Fig. 6B, each lens pattern LS of the multiple lens patterns LS has a vertex corresponding to height “b”, while each pattern HP of the multiple patterns HP has a vertex corresponding to height “b”. If the multiple lens patterns LS are arranged to overlap with the multiple patterns HP, each lens pattern LS overlaps with multiple patterns HP. For example, multiple vertices of the multiple patterns HP correspond to one vertex of a lens pattern LS. Figures 7A and 7B are schematic diagrams illustrating a mechanism for eliminating a flickering phenomenon. In the waveform graphs shown on the right side of Figures 7A and 7B, the horizontal direction represents the X-direction of the display device 100, and the vertical direction represents the intensity of light. As shown in Fig. 7A, when the display device 100 is in the ON state, the organic light-emitting element 160 contained in the display panel 310 is activated and emits light. In the process by which light generated by the organic light-emitting element 160 is emitted to the outside, it passes through various layers contained in the display panel 310. The light passing through the display panel 310 passes through the optical enhancement layer 210. Since the optical enhancement layer 210 contains an irregular pattern provided in the first pattern layer 211 and the second pattern layer 212, the light passing through the optical enhancement layer 210 can exhibit a waveform such as wave 1 in Fig. 7A. Meanwhile, the cover substrate 250 is a flat substrate, and when parallel light passes through the cover substrate 250, it can exhibit a waveform such as wave 2. Similarly, when light passing through the optical enhancement layer 210 passes through the cover substrate 250, the light after passing through the cover substrate 250 can exhibit a waveform that is a combination of wave 1 and wave 2 from Fig. 7A. As illustrated in Fig. 7B, when wave 1 and wave 2 are combined, destructive interference occurs, and light exhibiting a waveform as shown in the lower section of Fig. 7B is emitted. As illustrated in Fig. 7B, after passing through both the optical enhancement layer 210 and the cover substrate 250, the emitted light exhibits a small variation in light intensity depending on its position. Therefore, the pattern need not be visible to the user. In this way, when the optical enhancement layer 210 is used according to an embodiment of the present disclosure, the flickering phenomenon can be eliminated or reduced. Fig. 8A and Fig. 8B are schematic diagrams that explain the mechanism by which the sand phenomenon is eliminated. As shown in Fig. 8A, when the display device 100 is in the OFF state, reflected light due to external light may be clearly visible to the user. The light incident on the display device 100 can be reflected by the optical enhancement layer 210. Since the light passes through the irregular patterns provided in the first pattern layer 211 and the second pattern layer 212, the light reflected by the optical enhancement layer 210 can have a waveform such as wave 3 of Fig. 8A. Additionally, external light can be reflected by the cover substrate 250. The light reflected by the cover substrate 250 can have a waveform such as wave 4 in Fig. 8A. The user sees both the light reflected from the optical enhancement layer 210 and the light reflected from the cover substrate 250. Therefore, the light seen by the user can have a waveform that is a combination of wave 3 and wave 4 from Fig. 8A. As illustrated in Fig. 8B, when wave 3 and wave 4 are combined, destructive interference occurs, and light exhibiting a waveform as shown in the lower section of Fig. 8B is detected by the user. As illustrated in Fig. 8B, the light detected by the user exhibits a small variation in light intensity, which depends on the location. Therefore, the pattern need not be visible to the user. In this way, when the optical enhancement layer 210 is used according to an embodiment of the present disclosure, the sanding phenomenon can be eliminated or reduced. Refraction occurs in the optical enhancement layer 210 to eliminate or reduce the twinkling and sanding phenomena. Specifically, the refraction of light occurs at the interface between the first pattern layer 211 and the intermediate layer 214, and at the interface between the second pattern layer 212 and the filler layer 213. According to one embodiment of the present disclosure, as illustrated in Figs. 4 and 5, the intermediate layer 214 can be in contact with the first pattern layer 211. Additionally, the first pattern layer 211 and the intermediate layer 214 can have a refractive index difference in the range of 0.05 to 0.1. Due to this refractive index difference, light refraction can occur between the first pattern layer 211 and the intermediate layer 214. If the refractive index difference between the first pattern layer 211 and the intermediate layer 214 is less than 0.05, no significant refraction needs to occur at the boundary between the first pattern layer 211 and the intermediate layer 214. Additionally, if the refractive index difference between the first pattern layer 211 and the intermediate layer 214 exceeds 0.1, light generated by the organic light-emitting element 160 may have difficulty being emitted to the outside due to excessive refraction, and light loss due to total internal reflection may occur. Therefore, according to one embodiment of the present disclosure, the refractive index difference between the first pattern layer 211 and the intermediate layer 214 can be adjusted to a range of 0.05 to 0.1. According to one embodiment of the present disclosure, as illustrated in Figs. 4 and 5, the filler layer 213 can contact the second pattern layer 212. Additionally, the second pattern layer 212 and the filler layer 213 can have a refractive index difference in the range of 0.05 to 0.1. Due to this refractive index difference, light refraction can occur between the second pattern layer 212 and the filler layer 213. If the refractive index difference between the second pattern layer 212 and the filler layer 213 is less than 0.05, no significant refraction needs to occur at the interface between the second pattern layer 212 and the filler layer 213. Additionally, if the refractive index difference between the second pattern layer 212 and the filler layer 213 exceeds 0.1, light generated by the organic light-emitting element 160 may have difficulty being emitted to the outside due to excessive refraction, and light loss due to total internal reflection may occur. Therefore, according to one embodiment of the present disclosure, the refractive index difference between the second pattern layer 212 and the filler layer 213 can be adjusted to a range of 0.05 to 0.1. According to one embodiment of the present disclosure, the intermediate layer 214 can touch the first pattern layer 211 and the second pattern layer 212. According to one embodiment of the present disclosure, the light extraction efficiency of the display device 100 can be improved by allowing light to pass directly through the intermediate layer 214 and the second pattern layer 212 without being refracted. For this purpose, the difference in refractive index between the intermediate layer 214 and the second pattern layer 212 can be adjusted to 0.01 or less. If the difference in refractive index between the intermediate layer 214 and the second pattern layer 212 is 0.01 or less, light passing through the intermediate layer 214 can reach the second pattern layer 212 without being refracted. Specifically, the intermediate layer 214 can have the same refractive index as the second sample layer 212. Additionally, the intermediate layer 214 can be made of the same material as the second sample layer 212. The refractive indices of the first pattern layer 211, the second pattern layer 212, the filler layer 213 and the intermediate layer 214 can vary depending on the materials used, curing conditions or the like, and the refractive indices of each layer can be set independently. According to one embodiment of the present disclosure, the difference in refractive index between the first pattern layer 211 and the intermediate layer 214 can be equal to the difference in refractive index between the second pattern layer 212 and the filler layer 213. In this case, the number of cases relating to refractive index can be reduced, thereby simplifying the design of the display device 100. The filler layer 213 can have the same refractive index as the cover substrate 250. Additionally, the second adhesive element 290 between the filler layer 213 and the cover substrate 250 can also have the same refractive index as the filler layer 213 and the cover substrate 250. In this case, when light generated by the organic light-emitting element 160 passes through the filler layer 213, the second adhesive element 290, and the cover substrate 250 and is emitted to the outside, unnecessary light loss due to interfacial reflection can be prevented or reduced. Referring to Fig. 4, the display panel 310 includes a cover layer 185, and a first pattern layer 211 can be arranged on the cover layer 185. The cover layer 185 can have the same refractive index as the first pattern layer 211. Additionally, the first adhesive element 190 between the cover layer 185 and the first pattern layer 211 can also have the same refractive index as the cover layer 185 and the first pattern layer 211. In this case, unnecessary light loss due to interfacial reflection can be prevented or suppressed when light generated by the organic light-emitting element 160 passes through the color filter layer 150, the cover layer 185, the first adhesive element 190, and the first pattern layer 211. Fig. 9 is a partial cross-sectional view of a display device 200 according to a further embodiment of the present disclosure. Descriptions of components that have already been described are omitted below to avoid duplication. Referring to Fig. 9, the intermediate layer 214 and the second pattern layer 212 can be formed in one piece. For example, the intermediate layer 214 can be formed on the first pattern layer 211, and the upper surface of the intermediate layer 214 can be patterned such that the upper section of the intermediate layer 214 is the second pattern layer 212, thus forming the intermediate layer 214 and the second pattern layer 212 in one piece. Since the intermediate layer 214 and the second pattern layer 212 are formed as one body, the light loss between the intermediate layer 214 and the second pattern layer 212 can be minimized or prevented. Additionally, the first sample layer 211 and the second sample layer 212 can have a refractive index difference in the range of 0.05 to 0.1. Since the first sample layer 211 and the second sample layer 212 have a refractive index difference, light refraction can occur at the interface between the first sample layer 211 and the second sample layer 212. Additionally, the second pattern layer 212 and the filler layer 213 can have a refractive index difference in the range of 0.05 to 0.1. Since the second pattern layer 212 and the filler layer 213 have a refractive index difference, light refraction can occur at the interface between the second pattern layer 212 and the filler layer 213. According to one embodiment of the present disclosure, the first pattern layer 211 and the filler layer 213 can be made of the same material. Additionally, the first pattern layer 211 and the filler layer 213 can have the same refractive index. Since the intermediate layer 214 and the second pattern layer 212 are formed in one piece in the display device 200 of Fig. 9, if the first pattern layer 211 and the filler layer 213 have the same refractive index, the difference in refractive index between the first pattern layer 211 and the intermediate layer 214 can be equal to the difference in refractive index between the second pattern layer 212 and the filler layer 213.If the difference in refractive index between the first pattern layer 211 and the intermediate layer 214 is equal to the difference in refractive index between the second pattern layer 212 and the filler layer 213, the number of cases relating to refractive index can be reduced and the selection of materials can be simplified, thereby facilitating the manufacture and design of the display device 200. Figs. 10, 11, 12, 13, 14, 15 to 16 are partial cross-sectional views of an optical enhancement layer 210, each of which is applied to a display device according to a further embodiment of the present disclosure. Referring to Fig. 10, in an optical enhancement layer 210 of a display device 300 according to a further embodiment of the present disclosure, a filler layer 213 and an intermediate layer 214 can be arranged between a first pattern layer 211 and a second pattern layer 212. The filler layer 213 and the intermediate layer 214 can be in contact with each other. Specifically, the intermediate layer 214 can touch the first pattern layer 211 and the filler layer 213, and the filler layer 213 can touch the second pattern layer 212 and the intermediate layer 214. The optical enhancement layer 210, illustrated in Fig. 10, corresponds to a structure in which the projections of the first pattern layer 211 and the projections of the second pattern layer 212 are arranged such that they face each other. In this case, the first pattern layer 211 and the second pattern layer 212 can be spaced apart from each other as far as possible. Referring to Fig. 10, the filler layer 213 and the intermediate layer 214 can have the same refractive index. In this case, unnecessary light refraction at the interface between the filler layer 213 and the intermediate layer 214 can be prevented or suppressed, thereby improving the light extraction efficiency of the display device 300. According to a further embodiment of the present disclosure, the filler layer 213 and the intermediate layer 214 can be formed from the same material. Additionally, the first sample layer 211 and the second sample layer 212 can have the same refractive index. Specifically, the first sample layer 211 and the second sample layer 212 can be made of the same material. Fig. 11 illustrates an optical enhancement layer 210 of a display device 400 according to a further embodiment of the present disclosure. With reference to Fig. 11, the filler layer 213 and the intermediate layer 214 can be formed in one piece. The structure of Fig. 11 can also be described as a structure in which the first pattern layer 211 and the second pattern layer 212 are formed from the same material. According to the structure of Fig. 11, since there is no interface between the filler layer 213 and the intermediate layer 214, unnecessary light refraction is prevented or suppressed, such that the light extraction efficiency of the display device 400 can be improved. In the optical enhancement layer 210, illustrated in Fig. 11, the difference in refractive index between the first pattern layer 211 and the intermediate layer 214 can be equal to the difference in refractive index between the second pattern layer 212 and the filler layer 213. Fig. 12 illustrates an optical enhancement layer 210 of a display device 500 according to a further embodiment of the present disclosure. With reference to Fig. 12, a filler layer 213 can be arranged between a first pattern layer 211 and a second pattern layer 212. The optical enhancement layer 210 illustrated in Fig. 12 can be described as having a structure in which a first pattern layer 211 is arranged on a second pattern layer 212. Referring to Fig. 12, a first film is produced which contains a first pattern layer 211 and an intermediate layer 214, a second film is produced which contains a second pattern layer 212 and a filler layer 213, and then the first film is applied to the second film, thereby producing an optical enhancement layer 210, as illustrated in Fig. 12. When the optical enhancement layer 210, illustrated in Fig. 12, is arranged on the display panel 310, the intermediate layer 214 can touch the display panel 310. At present, the intermediate layer 214 of the optical enhancement layer 210 is directly connected to the display panel 310 without the first adhesive element 190, thereby reducing the distance between the display panel 310 and the first pattern layer 211 and the second pattern layer 212. At present, the intermediate layer 214 can be made of an adhesive material to ensure the adhesion of the optical enhancement layer 210. Fig. 13 illustrates an optical enhancement layer 210 of a display device 600 according to a further embodiment of the present disclosure. The structure illustrated in Fig. 13 corresponds to the structure of the optical enhancement layer 210 illustrated in Fig. 12, wherein the filler layer 213 and the first pattern layer 211 are formed in one piece. With reference to Fig. 13, the filler layer 213 and the first pattern layer 211 can be made of the same material. In this case, the first sample layer 211 and the second sample layer 212 can have a refractive index difference in the range of 0.05 to 0.1. In this case, significant light refraction can occur at the interface between the first sample layer 211 and the second sample layer 212. Fig. 14 illustrates an optical enhancement layer 210 of a display device 700 according to a further embodiment of the present disclosure. Referring to Fig. 14, a first pattern layer 211 and a second pattern layer 212 can touch each other. At present, the projections of the first pattern layer 211 and the projections of the second pattern layer 212 can project in opposite directions. Referring to Fig. 14, a first film is formed, containing a first pattern layer 211 and an intermediate layer 214. A second film is formed, containing a second pattern layer 212 and a filler layer 213. The first film and the second film are then applied, forming an optical enhancement layer 210, as illustrated in Fig. 14. At this stage, the first film and the second film can be applied such that the first pattern layer 211 and the second pattern layer 212 adhere to each other. When the optical enhancement layer 210, illustrated in Fig. 14, is arranged on the display panel 310, the intermediate layer 214 can contact the display panel 310. At present, the intermediate layer 214 of the optical enhancement layer 210 can be bonded directly to the display panel 310 without the first adhesive element 190. For this purpose, the intermediate layer 214 can be made of an adhesive material. Fig. 15 illustrates an optical enhancement layer 210 of a display device 800 according to a further embodiment of the present disclosure. The structure illustrated in Fig. 15 corresponds to the structure of the optical enhancement layer 210 illustrated in Fig. 14, wherein the first pattern layer 211 and the second pattern layer 212 are formed in one piece. In this case, the first pattern layer 211 and the second pattern layer 212 can be made of the same material. Fig. 16 illustrates an optical enhancement layer 210 of a display device 900 according to a further embodiment of the present disclosure. The optical enhancement layer 210 illustrated in Fig. 16 may further include a spacer 219. The spacer 219 may be arranged between the intermediate layer 214 and the filler layer 213. The optical enhancement layer 210, illustrated in Fig. 16, is the same as the structure in which a first pattern layer 211, an intermediate layer 214, a filler layer 213 and a second pattern layer 212 are arranged sequentially, as illustrated in Fig. 10, and a spacer 219 is arranged between the intermediate layer 214 and the filler layer 213. The thickness of the optical enhancement layer 210 can be controlled by the spacer 219 and the distance between the first pattern layer 211 and the second pattern layer 212 can be controlled. Referring to Figures 9-16, the vertices of the multiple lens patterns LS contained in the first pattern layer 211 and the vertices of the multiple patterns HP contained in the second pattern layer 212 can be oriented in different directions with respect to the scoreboard 310. For example, the vertices of the multiple lens patterns LS and the vertices of the multiple patterns HP can be oriented in the same direction, as shown in Figures 9, 12, and 13. If the vertices of the multiple lens patterns LS and the vertices of the multiple patterns HP are oriented in the same direction, the vertices can be oriented away from the scoreboard 310, as shown in Figure 9, or they can be oriented forward from the scoreboard, as shown in Figures 12 and 13. Furthermore, the vertices of the multiple lens patterns LS and the vertices of the multiple patterns HP can be oriented in different directions, as shown in Figs. 10, 11, 14, 15, and 16. If the vertices of the multiple lens patterns LS and the vertices of the multiple patterns HP are oriented in different directions, the vertices can be facing each other, as shown in Figs. 10, 11, and 16, or facing away from each other, as shown in Figs. 14 and 15. If the vertices of the multiple lens patterns LS and the vertices of the multiple patterns HP are oriented in different directions, one of the vertices of the multiple lens patterns LS and the vertices of the multiple patterns HP can face the scoreboard 310, while the others face away from the scoreboard. The removal and reduction of sparkle and sand phenomena are explained below with reference to comparative examples. Fig. 17A is a partial cross-sectional view of a display device according to comparative example 1 and Fig. 17B is a partial cross-sectional view of a display device according to comparative example 2. The display device (comparative example 1) illustrated in Fig. 17A does not include an optical enhancement layer 210 according to one embodiment of the present disclosure. The display device (comparative example 1) illustrated in Fig. 17A includes a display panel 310, a second adhesive element 290 on the display panel 310, and a covering substrate 250 on the second adhesive element 290. The display device (comparative example 2), illustrated in Fig. 17B, does not include the optical enhancement layer 210 according to one embodiment of the present disclosure and includes a lens layer 280. The lens layer 280 includes a first pattern layer 211 and an intermediate layer 214. In detail, the display device (comparative example 2), illustrated in Fig. 17B, includes a display panel 310, the first adhesive element 190 on the display panel 310, a lens layer 280 on the first adhesive element 190, a second adhesive element 290 on the lens layer 280, and a cover substrate 250 on the second adhesive element 290. Fig. 18 is an image showing the removal of sparkle and sand phenomena. In Fig. 18, the image shown as “internal light” is a photograph taken of the display device surface of the display device when the display device was in the ON state and light was emitted from inside the display device. In Fig. 18, the image indicated as “external light” is a photograph of the light reflected when a point light source is shone onto the display device when the display device 100 is in the off state. When internal light is emitted from the display devices of comparison examples 1 and 2, it can be confirmed that a sparkle such as small bubbles is produced. Additionally, when the display device is in the OFF state and external light (an illumination) is shone onto the display devices of Comparative Example 1 and Comparative Example 2, it can be confirmed that a blurred sand phenomenon occurs, as if sand is scattered around the point where the external light is reflected. On the other hand, it can be confirmed that no sparkling is generated and no sand phenomenon occurs in the display device according to embodiment 1. Another embodiment of the present disclosure provides an optical enhancement layer 210. The optical enhancement layer 210 can be formed in the form of a thin layer or a film. The optical enhancement layer 210 can be attached to and used on a display panel 310. Since the exact configuration of the optical enhancement layer 210 has already been described in Figures 5, 9, 10, 11, 12, 13, 14, 15 to 16, a detailed description of the configuration of the optical enhancement layer 210 is omitted to avoid duplication. In the following, with reference to the manufacturing process drawing, a method for producing an optical enhancement layer 210 according to an embodiment of the present disclosure is described. Figures 19A to 19H are schematic cross-sectional views illustrating a method for producing an optical enhancement layer according to an embodiment of the present disclosure. Referring to Fig. 19A, a first translucent resin layer 211m is formed on a support substrate 450. A glass substrate or a plastic substrate in the form of a thin layer can be used as the support substrate 450. Referring to Fig. 19B, the first translucent resin layer 211m is patterned using the first rolling element 410. The pattern formation can be achieved by creating a negative pattern on the first translucent resin layer 211m using the first rolling element 410. Referring to Fig. 19C, a first pattern layer 211 is formed by pattern formation using a first rolling element 410. Referring to Fig. 19D, an intermediate layer 214 is formed on the first pattern layer 211. The intermediate layer 214 can be made of a translucent resin. Referring to Fig. 19E, a second light-transmitting resin layer 212m is formed on the intermediate layer 214. Referring to Fig. 19F, the second translucent resin layer 212m is patterned using the second rolling element 420. The pattern formation can be achieved by creating an engraved pattern on the second translucent resin layer 212m using the second rolling element 420. Referring to Fig. 19G, a second pattern layer 212 is formed by pattern formation using a second rolling element 420. Referring to Fig. 19H, a filler layer 213 is formed on the second pattern layer 212. The filler layer 213 can be made of a translucent resin. One result is the creation of an optical enhancement layer 210, as illustrated in Fig. 19H. After the optical enhancement layer 210 has been created, the support substrate 450 is removed. Figures 20A to 20C are schematic perspective views illustrating a method for producing a first rolling element 410 for forming a first pattern layer 211. Referring to Fig. 20A, a first core 411 is produced to manufacture a first rolling element 410. Referring to Fig. 20B, a plating layer 412 is formed on the turned part of the first core 411. The plating layer 421 can contain a copper plating layer (Cu plating layer) and a nickel plating layer (Ni plating layer). Referring to Fig. 20C, the plating layer 412 is subjected to laser processing. A laser generating device 415 is used for laser processing. A hemispherical concave section, corresponding to the lens pattern, is formed in the plating layer 412 by laser processing. As a result, a first rolling element 410 can be produced. According to one embodiment of the present disclosure, the size of the hemispherical concave section formed in the plating layer 412 of the first rolling element 410 is not constant and is random. Figures 21A to 21C are schematic perspective views illustrating a manufacturing process for a second rolling element 420 for forming the second pattern layer 212. Referring to Fig. 21A, the second core 421 is manufactured to produce a second rolling element 420. Referring to Fig. 21B, the plating layer 422 is formed on the turned part of the second core 421. The plating layer 422 can contain a copper plating layer (Cu plating layer) and a nickel plating layer (Ni plating layer). Referring to Fig. 21C, the plating layer 422 is sand-treated. Sandblasting 425 can be used for the sand treatment. The high-strength fine particles 426, such as emery, are sprayed onto the plating layer 422 by sandblasting 425. The concave section, corresponding to the horn shape, is formed in the plating layer 422 by sand treatment. As a result, a second rolling element 420 can be produced. According to one embodiment of the present disclosure, the size of the horn-shaped concave section formed in the plating layer 422 of the second rolling element 420 is not constant and is random. The present disclosure described above is not limited to the embodiments described above and the accompanying drawings, and it will be apparent to a person skilled in the art in the field of the present disclosure that various substitutions, modifications and alterations are possible to an extent that does not deviate from the technical details of the present disclosure. According to one embodiment of the present disclosure, the optical enhancement layer, which includes a first pattern layer and a second pattern layer having different pattern shapes and pattern sizes, is arranged on a display panel, thereby effectively preventing or suppressing the occurrence of a flickering phenomenon or a sanding phenomenon in a display device. The optical film according to an embodiment of the present disclosure comprises a first pattern layer and a second pattern layer having different pattern shapes and pattern sizes, and can be applied to a display panel to effectively prevent or suppress a flickering phenomenon or a sanding phenomenon occurring in a display device. According to the present disclosure, the flickering phenomenon that occurs in a display device when an internal light-emitting element emits light (ON state) can be effectively suppressed or prevented, and the sanding phenomenon that occurs in a display device when external light is reflected from a display device surface can be effectively suppressed or prevented. According to one embodiment of the present disclosure, the flickering phenomenon or the sanding phenomenon that occurs in the display device can be effectively prevented or suppressed, and the display device can exhibit excellent display device quality. In addition to the effects mentioned above, further features and benefits of the present revelation are described below or can be clearly understood by experts in the field to which the revelation belongs from such a description and explanation. QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature KR 10-2024-0200134

[0001]

Claims

Display device (100, 200, 300, 400, 500, 600, 700, 800, 900) comprising: a display panel (310) having pixels; and an optical enhancement layer (210) on the display panel; wherein the optical enhancement layer (210) comprises a first pattern layer (211) and a second pattern layer (212) overlapping each other, the first pattern layer (211) having a first refractive index, the second pattern layer (212) having a second refractive index different from the first refractive index, the first pattern layer (211) having an average pattern size larger than that of the second pattern layer (212), and the average pattern ratios of patterns contained in the first pattern layer (211) being smaller than the average pattern ratios of patterns contained in the second pattern layer (212).the average pattern size is an average value of the maximum diameter of each pattern in a top-down view for each of the first pattern layer (211) and the second pattern layer (212), each pattern ratio is calculated as “b / a”, where “a” denotes a maximum diameter of each pattern and “b” denotes a height of each pattern for the patterns contained in the first pattern layer (211) and the patterns contained in the second pattern layer (212), and the average of the pattern ratios is calculated as an average value of the pattern ratios of the respective patterns. Display device (100, 200, 300, 400, 500, 600, 700, 800, 900) according to claim 1, wherein the first pattern layer (211) has several lens patterns and the second pattern layer (212) contains several horn-shaped patterns. Display device (100, 200, 300, 400, 900) according to claim 1 or 2, wherein the optical enhancement layer (210) further comprises an intermediate layer (214) on the first pattern layer (211). Display device (100, 200, 300, 400, 900) according to claim 3, wherein the intermediate layer (214) touches the first pattern layer (211) and the refractive index difference between the first pattern layer (211) and the intermediate layer is in the range of about 0.05 to about 0.

1. Display device (100, 200, 400) according to claim 3 or 4, wherein the intermediate layer (214) contacts the first pattern layer (211) and the second pattern layer (212) and the refractive index difference between the intermediate layer (214) and the second pattern layer (212) is about 0.01 or less. Display device (200) according to one of claims 3 to 5, wherein the intermediate layer (214) contains the same material as the second pattern layer (212) and / or the intermediate layer (214) is formed in one piece with the second pattern layer (212). The display device (200) according to claim 6, wherein the refractive index difference between the first pattern layer (211) and the second pattern layer (212) is in the range of about 0.05 to about 0.

1. Display device (100, 200, 300, 400, 500, 600, 700, 800, 900) according to one of the preceding claims, wherein the optical enhancement layer (210) further comprises a filler layer (213) on or below the second pattern layer (212). Display device (100, 200, 300, 400, 500, 600, 700, 800, 900) according to claim 8, wherein the filler layer (213) touches the second pattern layer (212) and the refractive index difference between the second pattern layer (212) and the filler layer (213) is in the range of about 0.05 to about 0.

1. Display device (300, 400, 600, 900) according to claim 8 or 9, wherein the intermediate layer (214) and the filler layer (213) are arranged between the first pattern layer (211) and the second pattern layer (212) and / or the intermediate layer and the filler layer contain the same material. Display device (900) according to claim 10, wherein the optical enhancement layer (210) further comprises a spacer (219) arranged between the intermediate layer (214) and the filler layer (213). Display device (300, 400, 500, 600, 900) according to one of claims 8 to 11, wherein the filler layer (213) is arranged between the first pattern layer (211) and the second pattern layer (212) and / or the filler layer (213) is formed integrally with the first pattern layer (211). Display device (700, 800) according to one of claims 8 to 12, wherein the first pattern layer (211) touches the second pattern layer (212) and projections of the first pattern layer (211) and projections of the second pattern layer (212) protrude in opposite directions; wherein preferably the first pattern layer (211) is formed integrally with the second pattern layer (212). Display device (100, 200, 300, 400, 500, 600, 700, 800, 900) according to one of claims 8 to 13, wherein a refractive index difference between the first pattern layer (211) and the intermediate layer (214) is equal to a refractive index difference between the second pattern layer (212) and the filler layer (213). Display device (200) according to one of claims 8 to 14, which further comprises: a covering substrate (250) on the filling layer (213), wherein the filling layer has the same refractive index as the covering substrate. Display device (100, 200, 300, 400, 500, 600, 700, 800, 900) according to one of the preceding claims, wherein the display panel (310) includes a cover layer (185), the first pattern layer (211) is arranged on the cover layer and the cover layer has the same refractive index as the first pattern layer (211). Display device (100) according to one of the preceding claims, wherein the display panel contains a color filter layer (150) and the optical enhancement layer (210) is arranged on the color filter layer. Optical enhancement layer (210) for a display device, wherein the optical enhancement layer (210) comprises: a first pattern layer (211) and a second pattern layer (212) overlapping each other, wherein the first pattern layer (211) has a first refractive index, the second pattern layer (212) has a second refractive index different from the first refractive index, the first pattern layer (211) has an average pattern size larger than that of the second pattern layer (212), an average pattern ratio of patterns contained in the first pattern layer (211) is smaller than an average pattern ratio of patterns contained in the second pattern layer (212), and the average pattern size is an average value of the maximum diameter of the respective patterns in a top-view image for each of the first pattern layer (211) and the second pattern layer (212).Each pattern ratio is calculated as “b / a”, where “a” denotes a maximum diameter of each pattern and “b” denotes a height of each pattern for the patterns contained in the first pattern layer (211) and the patterns contained in the second pattern layer (212), and the average of the pattern ratios is calculated as an average value of the pattern ratios of the respective patterns. A method for producing an optical enhancement layer (210) for a display device, the method comprising: forming a first light-transmitting resin layer (211m) on a support substrate (450); forming a first pattern layer (211) by patterning on the first light-transmitting resin layer (211m) using a first rolling element (410), wherein the first rolling element (410) comprises a plating layer (412) having a hemispherical concave section; forming an intermediate layer (214) on the first pattern layer (211); forming a second light-transmitting resin layer (212m) on the intermediate layer (214); forming a second pattern layer (212) by patterning on the second light-transmitting resin layer (212m) using a second rolling element (420), wherein the second rolling element (420) comprises a sand-treated plating layer (422). includes a concave section;Forming a filler layer (213) on the second pattern layer (212) and removing the support substrate (450).; Display device comprising: a display board (310) having pixels; and an optical enhancement layer (210) on the display board;wherein the optical enhancement layer (210) comprises a first pattern layer (211) and a second pattern layer (212), wherein the first pattern layer (211) has a first refractive index and several first patterns with a first average pattern ratio, and the second pattern layer (212) has a second refractive index and several second patterns with a second average pattern ratio, the first average pattern ratio being smaller than the second average pattern ratio, the several second patterns overlapping with one pattern of the several first patterns, and each average pattern ratio of the respective first and second patterns being an average of "b / a", where "a" is a maximum diameter and "b" is a height of each pattern of the respective first and second patterns.

Images