Optical film

Abstract

An optical film according to various embodiments of the present disclosure may include a first sheet, a second sheet, and a third sheet, the first sheet includes a first base portion, a pyramid pattern layer in which a plurality of pyramid patterns having a base length of a first pitch and a diagonal length of 1-1 pitch are formed on a first surface of the first base portion, and a first prism pattern layer in which a plurality of prism patterns having a base length of a second pitch are formed on a second surface of the first base portion. The second sheet includes a second base portion, a second prism pattern layer having a plurality of prism patterns formed on a first surface of the second base portion, and a first diffusion layer formed on a second surface of the second base portion and disposed over the first sheet so as to face and overlap the pyramid pattern layer. The third sheet includes a third base portion, a third prism pattern layer having a plurality of prism patterns formed on a first surface of the third base portion, and a second diffusion layer formed on a second surface of the third base portion and disposed over the second sheet so as to face and overlap the third prism pattern layer.

Description

Technical Field

[0001] Various embodiments of the present disclosure relate to optical films used in liquid crystal display devices. Background Art

[0002] Generally, a liquid crystal display (LCD) device may include a backlight unit that uniformly irradiates light to the entire screen of an electronic device. The backlight unit may include a light source, a light guide plate, a diffuser, and an optical film including a prism. Light emitted from the light source may be transmitted to the upper portion through the light guide plate, and the light transmitted to the upper portion is diffused by the diffuser and then transmitted to the liquid crystal panel through the optical film disposed on the upper portion. Summary of the invention

[0003] Recently developed display devices are gradually becoming thinner, and thus, backlight units are also required to be manufactured to be thin. In the backlight unit, development is being conducted for removing a diffusion sheet having a relatively thick thickness. For example, as a backlight unit, in an embodiment including a light source, a light guide plate, a diffusion sheet, and a prism sheet, research is being conducted for removing the diffusion sheet or replacing it.

[0004] The diffusion sheet may have a diffusion layer formed on one side and / or the other side thereof. The diffusion layer generally includes light diffuser beads, which can diffuse the light provided from the light source and the light guide plate to a wider range than when directed toward the prism sheet and act as a shielding sheet to reduce the visibility of the light source.

[0005] However, since the diffusion sheet is generally thick and has an obstructive effect on the improvement of the brightness of the backlight unit, efforts are being made to replace it.

[0006] In addition, in the case where a sheet including a pyramid pattern and an inverted prism pattern is used instead of the diffusion sheet, a problem of causing moiré may occur due to the arrangement of the pyramid pattern and the inverted prism pattern.

[0007] The purpose of the present disclosure is to provide an optical film for liquid crystal display devices through various embodiments, which has excellent performance of preventing the shape of the light source from being observed (hereinafter referred to as "shielding performance") without using a thick diffuser and at the same time has high brightness (hereinafter referred to as "brightness performance").

[0008] Furthermore, an object of the present disclosure is to provide an optical film that effectively avoids moiré when a sheet including a pyramid pattern and an inverted prism pattern is used instead of a diffusion sheet.

[0009] According to various embodiments of the present disclosure, an optical film can be provided, wherein the optical film includes a first sheet, a second sheet, and a third sheet, wherein the first sheet includes a first base portion, a pyramid pattern layer having a plurality of pyramid patterns with a base length of a first pitch and a diagonal length of a 1-1th pitch formed on a first surface of the first base portion, and a first prism pattern layer having a plurality of first prism patterns with a base length of a second pitch formed on a second surface of the first base portion, the second sheet includes a second base portion, a second prism pattern layer having a plurality of second prism patterns formed on a first surface of the second base portion, and a first diffusion layer formed on a second surface of the second base portion, the first diffusion layer being arranged on the second surface of the second base portion facing and overlapping the pyramid pattern layer. A third sheet is disposed over a sheet, the third sheet comprising a third base portion, a third prism pattern layer having a plurality of third prism patterns formed on a first surface of the third base portion, and a second diffusion layer formed on a second surface of the third base portion, the second diffusion layer and the third prism pattern layer being arranged over the second sheet facing and overlapping each other, the plurality of first prism patterns having ridges formed in a first direction, the plurality of pyramid patterns being configured such that an extension direction of one of the bottom sides forms an angle of greater than 0 degrees and less than 45 degrees with the first direction, the plurality of second prism patterns having ridge lines formed in a second direction perpendicular to the first direction, and the plurality of third prism patterns having ridge lines formed in a third direction perpendicular to the second direction.

[0010] According to various embodiments of the present disclosure, a backlight unit with an optical film can be provided, the backlight unit including an edge-type light source and an optical film arranged above the light source, the optical film including a first sheet, a second sheet and a third sheet, the first sheet including a first base portion, a pyramid pattern layer having a plurality of pyramid patterns with a base length of a first pitch and a diagonal length of a 1-1 pitch formed on a first surface of the first base portion, and a first prism pattern layer having a plurality of first prism patterns with a base length of a second pitch formed on a second surface of the first base portion, the second sheet including a second base portion, a second prism pattern layer having a plurality of second prism patterns formed on a first surface of the second base portion, and a first diffusion layer formed on a second surface of the second base portion, the first The diffusion layer is arranged above the first sheet facing and overlapping the pyramid pattern layer, the third sheet includes a third base portion, a third prism pattern layer having a plurality of third prism patterns formed on a first surface of the third base portion, and a second diffusion layer formed on a second surface of the third base portion, the second diffusion layer is arranged above the second sheet facing and overlapping the third prism pattern layer, the plurality of first prism patterns have ridges formed toward a first direction, the plurality of pyramid patterns are configured so that an extension direction of one of the bottom edges forms an angle of greater than 0 degrees and less than 45 degrees with the first direction, the plurality of second prism patterns have ridge lines formed toward a second direction perpendicular to the first direction, and the plurality of third prism patterns have ridge lines formed toward a third direction perpendicular to the second direction.

[0011] According to various embodiments of the present disclosure, an optical film can be provided, which includes a first base portion, a pyramid pattern layer having a plurality of pyramid patterns with a base length of a first pitch and a diagonal length of a 1-1 pitch formed on a first surface of the first base portion, and a first prism pattern layer having a plurality of prism patterns with a base length of a second pitch formed on a second surface of the first base portion, the plurality of first prism patterns having ridges formed toward a first direction, and the plurality of pyramid patterns being configured such that an extension direction of one of the bases forms an angle of greater than 0 degrees and less than 45 degrees with the first direction.

[0012] According to various embodiments of the present disclosure, by not having a thick diffusion sheet, it is possible to contribute to a reduction in the thickness of the backlight unit.

[0013] According to various embodiments of the present disclosure, it is possible to provide an optical film having excellent shielding performance with respect to a light source and also excellent brightness performance, and a backlight unit including the optical film.

[0014] According to various embodiments of the present disclosure, it is possible to provide an optical film that reduces and / or prevents moiré and a backlight unit including the optical film.

[0015] Effects that can be obtained by the present disclosure are not limited to the above-mentioned effects, and other effects that are not mentioned can be clearly understood from the following description by those having ordinary skill in the technical field to which the present disclosure belongs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The aspects or other aspects, configurations and / or advantages described above with respect to an embodiment of the present disclosure will become more apparent through the following detailed description with reference to the accompanying drawings.

[0017] Figure 1 is a perspective view showing a liquid crystal display device including an optical film according to an embodiment.

[0018] Figure 2 is a diagram illustrating a liquid crystal display device including an optical film according to an embodiment.

[0019] Figure 3 is a diagram illustrating a liquid crystal display device including an optical film according to an embodiment.

[0020] Figure 4A is a cross-sectional view showing an optical film according to an embodiment.

[0021] Figure 4B is a cross-sectional view showing an optical film according to an embodiment.

[0022] Figure 4C is a cross-sectional view showing an optical film according to an embodiment.

[0023] Figure 4D is a diagram showing a pyramid pattern and a prism pattern according to an embodiment.

[0024] Figure 4E FIG. 1 is a diagram showing a state where a pyramid pattern layer before being stacked according to an embodiment is viewed from above.

[0025] Figure 4F FIG. 1 is a diagram showing a pyramid pattern layer in a stacked state according to an embodiment when viewed from above.

[0026] Figure 5A The configuration of an experiment for measuring the brightness of an optical film according to an embodiment is shown.

[0027] Figure 5B is a diagram showing an optimal incident angle for improving light distribution and brightness according to an embodiment.

[0028] Fig. 6A is a diagram illustrating a backlight unit including a sheet formed with an inverted prism pattern layer (first prism pattern layer) according to a certain embodiment and an edge type light source.

[0029] Figure 6B Graphs showing changes in the incident angle and the viewing angle corresponding to changes in the refractive index of the inverted prism pattern layer.

[0030] Figure 7 is a perspective view showing a liquid crystal display device including an optical film according to an embodiment.

[0031] Fig. 8A is a graph showing optical characteristics associated with a liquid crystal display device including a diffusion plate according to a specific embodiment.

[0032] Figure 8B is a diagram showing optical characteristics associated with a liquid crystal display device including an optical film according to an embodiment.

[0033] Figure 8C is a diagram showing optical characteristics associated with a liquid crystal display device including an optical film according to an embodiment.

[0034] Fig. 9A is a diagram showing optical characteristics associated with a liquid crystal display device including an optical film according to an embodiment.

[0035] Fig. 9B is a diagram showing optical characteristics associated with a liquid crystal display device including an optical film according to an embodiment.

[0036] Fig. 9C is a diagram showing optical characteristics associated with a liquid crystal display device including an optical film according to an embodiment.

[0037] Fig.9D is a diagram showing optical characteristics associated with a liquid crystal display device including an optical film according to an embodiment.

[0038] Fig. 10A is a diagram showing a state of a liquid crystal panel corresponding to an arrangement of a first prism pattern layer and a pyramid pattern layer according to an embodiment.

[0039] Fig. 10B is a diagram showing a state of a liquid crystal panel corresponding to an arrangement of a first prism pattern layer and a pyramid pattern layer according to an embodiment.

[0040] Throughout the accompanying drawings, like reference numerals may be assigned to like components, configurations and / or structures.

[0041] Description of Reference Numerals

[0042] 1: liquid crystal display device; 10: backlight unit; 11: light source; 12: light guide plate; 13: reflector; 17: diffuser; 20: liquid crystal panel; 100: optical film; 110: first sheet; 111: pyramid pattern layer; 112: first base; 113: first prism pattern layer; 120: second sheet; 121: second prism pattern layer; 122: second base; 123: first diffuser; 130: third sheet; 131: third prism pattern layer; 132: third base; 133: second diffuser DETAILED DESCRIPTION

[0043] The various embodiments of the present disclosure and the terms used therein are not intended to limit the technical features recorded in the present disclosure to specific embodiments, but should be understood to include various changes, equivalents or substitutes of the corresponding embodiments. In connection with the description of the drawings, similar reference numerals may be used for similar or related constituent elements. In the absence of a clear indication of a different meaning in the context, the singular form of a noun corresponding to an item may include one or more of the items.

[0044] According to various embodiments, each constituent element (e.g., module or program) of the constituent elements described may include a single or multiple individuals, and a portion of the multiple individuals may also be separately arranged in other constituent elements. According to various embodiments, one or more constituent elements or actions in the aforementioned corresponding constituent elements may be omitted, or one or more other constituent elements or actions may be added. Alternatively or additionally, multiple constituent elements (e.g., module or program) may be integrated into one constituent element. In this case, the integrated constituent element may perform one or more functions of each constituent element in the multiple constituent elements in the same or similar manner as the situation performed by the corresponding constituent elements in the multiple constituent elements before being integrated. According to various embodiments, the actions performed by modules, programs or other constituent elements may be performed sequentially, in parallel, repeatedly or heuristically, or one or more actions in the actions may be performed in different orders, or omitted, or one or more other actions may be added.

[0045] Various embodiments are described with reference to the accompanying drawings. In the process of describing the present embodiment, the same names and the same figure numbers will be used for the same components, and the corresponding additional descriptions will be omitted. In addition, it is preliminarily explained that in the process of describing the embodiments of the present disclosure, only the same names and the same figure numbers will be used for the components with the same functions, which are not substantially the same as the existing ones.

[0046] According to various embodiments, it should be understood that terms such as “including” or “having” are intended to specify the presence of features, numbers, steps, actions, constituent elements, parts, or a combination thereof recorded in the specification, but are not intended to pre-exclude the presence or additional possibilities of one or more other features, numbers, steps, actions, constituent elements, parts, or a combination thereof.

[0047] Figure 1 is a perspective view showing a liquid crystal display device including an optical film according to an embodiment.

[0048] In the following detailed description, the length direction (vertical direction) of the liquid crystal display device 1 may be defined as the "Y-axis direction", the width direction (horizontal direction) may be defined as the "X-axis direction", and / or the height direction (thickness direction) may be defined as the "Z-axis direction". In addition, in a specific embodiment, with respect to the direction in which the constituent elements point, "negative / positive (- / +)" may be referred to together with the orthogonal coordinate system illustrated in the accompanying drawings. Figure 1 As shown, in the case where "negative / positive (- / +)" is not recorded in the orthogonal coordinate system, unless additionally defined, it can be interpreted that the corresponding coordinate axis points to the + direction. For example, the "X-axis direction" can be interpreted as pointing to the +X-axis direction, and the "Y-axis direction" can be interpreted as pointing to the +Y-axis direction. In addition, the "Z-axis direction" can be interpreted as pointing to the +Z-axis direction. For example, referring to Figure 1 , when it is described that the second sheet 120 is arranged above the first sheet 110, it can be defined as that the second sheet 120 is arranged in the "+Z axis direction (or first direction)" from the first sheet 110. For another example, referring to Figure 4A , one side of the first base portion 112 (for example, the first side 112a) can be defined as a "side facing the +Z axis direction (or the first direction)", and the other side (for example, the second side 112b) is defined as a "side facing the -Z axis direction (or the second direction)". According to one embodiment, in the description of the optical film 100, the direction of travel of the light source can be expressed as the "+Z axis direction", for example. In the process of describing the direction, when describing the direction below, when describing the direction as pointing to one of the three axes of the orthogonal coordinate system, the situation of pointing to the direction parallel to the axis can be included. This is only for the sake of simplicity in explanation and is based on the orthogonal coordinate system recorded in the accompanying drawings. It should be noted that such descriptions related to directions or constituent elements do not limit the various embodiments of the present disclosure.

[0049] Reference Figure 1, a liquid crystal display device (or LCD (liquid crystal display) device) 1 may include a backlight unit 10 and a liquid crystal panel 20. According to various embodiments, the backlight unit 10 may face the back side of the liquid crystal panel 20 (the side facing the -Z axis direction) to radiate light to the liquid crystal panel 20. The backlight unit 10 may include a light source 11, a light guide plate 12, a reflective plate 13, an optical film 100, and a diffuser 17. Although not shown in the figure, the backlight unit 10 may further include a reflective polarizer.

[0050] The light source 11 is a structure for emitting light toward the back of the liquid crystal panel 20, and can be arranged at one side of a light guide plate 12 (LPG). The light source can be classified into an edge type or a direct type according to the arrangement structure, and in the present disclosure, as shown in FIG. Figure 1 As shown, an edge-type light source can be applied. The light source 11 is used to irradiate light to the back of the liquid crystal panel 20, and the light emitted from the light source 11 can be transformed into a surface light source under the action of the light guide plate 12. At this time, the light source 11 can be a cold cathode fluorescent lamp (CCFL) or an external electrode fluorescent lamp (externalelectrodefluorescentlamp). The reflective plate 13 can be arranged behind the light guide plate 12, and the light emitted toward the rear of the light guide plate 12 (the surface toward the -Z axis direction) is reflected and incident toward the light guide plate 12, thereby minimizing the loss of light. That is, the reflective plate 13 can perform light recycling.

[0051] Reference Figure 1 , the light emitted from the light guide plate 12 is incident on the optical film 100, and the optical film 100 of the present disclosure has at least one prism sheet for collecting light, and as a sheet for uniformly dispersing the light incident from the light guide plate 12 so that it is incident on the prism sheet, it may also include a sheet including a pyramid pattern. For the convenience of explanation, the prism sheet or a combination of two or more prism sheets for collecting light included in the optical film 100 below may be referred to as a "collecting prism sheet" (or "orthogonal prism sheet"), and the sheet including the pyramid pattern may be referred to as a "pyramid sheet".

[0052] Although it will be described in detail below, in the optical film 100 of the present disclosure, as a pyramid sheet, a first sheet 110 may be included, and the first sheet 110 has a pyramid pattern formed on one side thereof facing a direction parallel to the traveling direction of the light source (for example, the Z-axis direction), and a prism pattern (i.e., an inverted prism pattern) is formed on the other side thereof facing a direction opposite to the traveling direction of the light source. In addition, in the optical film 100 of the present disclosure, as a focusing prism sheet, a second sheet 120 may be included, and the second sheet 120 has a prism pattern formed on one side thereof facing a direction parallel to the traveling direction of the light source (for example, the +Z-axis direction), and a diffusion layer is formed on the other side thereof facing a direction opposite to the traveling direction of the light source. According to one embodiment, in the optical film 100 of the present disclosure, as a focusing prism sheet, in addition to the second sheet 120, a third sheet 130 including a prism pattern having a ridge line direction different from the prism pattern formed on the second sheet 120 may be included.

[0053] The focusing prism sheet (the second sheet 120 and / or the third sheet 130) can use the optical pattern formed on its surface to focus the incident light and then emit it to the liquid crystal panel 20. The focusing prism sheet (the second sheet 120 and / or the third sheet 130) may include a light-transmitting base film and a prism pattern layer formed on the upper surface of the base film (the surface facing the +Z axis direction). In order to increase the brightness in the surface direction, the prism pattern layer can be formed as an optical pattern layer in the form of a triangular array (array) with an inclined surface at a specified angle (for example, an inclined surface of 45°). The prism pattern of the prism pattern layer can be in the shape of a triangular prism, and one side of the triangular prism can be arranged to face the base film. The cross section of each of the prism patterns can be a triangle.

[0054] According to one embodiment, the focusing prism sheet (the second sheet 120 and / or the third sheet 130) may include the second sheet 120 and the third sheet 130 to form a composite prism sheet structure. Here, the third sheet 130 may be arranged in an overlapping manner above the second sheet 120. In the second sheet 120, a plurality of second prism patterns may be arranged side by side with each other. Each second prism pattern may be in a structure extending in one direction. For example, the vertex line (hereinafter referred to as "(or ridge or crest)") of each of the second prism patterns may be formed by extending in the direction of the X-axis. Similarly, in the third sheet 130, a plurality of third prism patterns may also be arranged side by side with each other. Each third prism pattern may be in a structure extending in one direction. For example, the ridge line of each of the third prism patterns may be formed by extending in the direction of the Y-axis perpendicular to the X-axis. Here, for the convenience of explanation, the extension direction of the first prism pattern and the extension direction of the second prism pattern are illustrated as being toward the X-axis and the Y-axis. However, it is not limited to the illustrated embodiment, and it should be noted that the direction may be other than the X-axis or the Y-axis.

[0055] According to one embodiment, a prism pattern (a plurality of first prism patterns) may also be formed in the pyramid sheet (the first sheet 110). Unlike the plurality of second prism patterns included in the second sheet 120 and the plurality of third prism patterns included in the third sheet 130, the plurality of first prism patterns included in the first sheet 110 may be formed to protrude in the opposite direction (-Z axis direction) relative to the direction of light travel, rather than in the direction (+Z axis direction) parallel to the direction of light travel. Therefore, the plurality of first prism patterns included in the first sheet 110 may be referred to as "inverted prism patterns". The ridge line direction P1 of the plurality of first prism patterns may be formed to be the same as or different from the ridge line direction P2 of the plurality of second prism patterns and the ridge line direction P3 of the plurality of third prism patterns. According to one embodiment, as Figure 1 As shown, the ridge line direction P1 of the plurality of first prism patterns can be formed to be orthogonal to the ridge line direction P2 of the plurality of second prism patterns and parallel to the ridge line direction P3 of the plurality of third prism patterns, and the liquid crystal display device 1 of the present disclosure can enjoy the corresponding effect. A more detailed description related to the ridge line direction will be described later.

[0056] The diffuser 17 can evenly disperse the light incident from the optical film 100. The diffuser 17 can be coated with a solution of a hardening resin (for example, at least one selected from urethane acrylate, epoxy acrylate, acrylate, and a free radical generating monomer, either alone or in combination) to which light diffuser beads are added, thereby causing light diffusion through the light diffuser beads. In addition, the diffuser 17 can also be formed with a convex pattern (or protrusion) of uniform or uneven size and shape (for example, spherical, hemispherical, or elliptical) to promote light diffusion. According to a specific embodiment of the prior art, as the diffuser 17, in addition to being arranged on Figure 1 In addition to the upper diffusion sheet 17 above the condensing prism sheet, a lower diffusion sheet arranged below the condensing prism sheet may also be included. However, in the present disclosure, the lower diffusion sheet may be replaced by providing an optical film 100 combining a condensing prism sheet and a pyramid sheet.

[0057] According to an embodiment, the backlight unit 10 may omit at least one of the above-mentioned constituent elements (eg, the diffusion sheet 17 ), or may add one or more other constituent elements (eg, a reflective polarizing sheet (not shown)).

[0058] A reflective polarizer (not shown) may be disposed on the optical film 100 and the diffuser 17 to transmit a portion of the polarized light focused from the optical film 100 and diffused by the upper diffuser and reflect the rest of the polarized light downward.

[0059] The liquid crystal panel 20 may refract light emitted from the light source 11 into a predetermined pattern according to an electrical signal. The refracted light may pass through a color filter and a polarization filter disposed on the front surface of the liquid crystal panel 20 to constitute a screen.

[0060] Said Figure 1 The constituent elements included in the liquid crystal display device 1 may be assembled in a state where they are overlapped and stacked with other constituent elements in the height direction (+Z axis direction). Figure 1 As shown, in the liquid crystal display device 1 according to the specific embodiment, the backlight unit 10 and the liquid crystal panel 20 , which are respectively manufactured separately, may be overlapped and stacked in the height direction (+Z axis direction).

[0061] Figure 2 is a diagram illustrating a liquid crystal display device including an optical film according to an embodiment. Figure 3 is a diagram illustrating a liquid crystal display device including an optical film according to an embodiment.

[0062] Figure 2 A cross section parallel to a plane formed by the Y-axis and the Z-axis of the liquid crystal display device 1 can be represented, and Figure 3A cross section parallel to a plane formed by the X-axis and the Z-axis of the liquid crystal display device 1 can be shown. Figure 1 The descriptions related to the repeated parts will be omitted.

[0063] The liquid crystal display device 1 of the present disclosure may be characterized in that no additional diffusion sheet (eg, lower diffusion sheet) is separately provided between the optical film 100 and the light guide plate 12 , but only the optical film 100 of the present disclosure is used to replace the diffusion sheet.

[0064] In this disclosure, Figures 1 to 3 As shown, the “optical film 100” may be a film including a first sheet 110 having a plurality of pyramid patterns formed on one side, a second sheet 120 disposed above the first sheet 110 and having a plurality of prism patterns formed on one side, and a third sheet 130 disposed above the second sheet 120 and having a plurality of prism patterns formed on one side. Figures 1 to 3 , the first sheet 110, the second sheet 120 and the third sheet 130 are shown to be separated from each other, but differently from this, the first sheet 110, the second sheet 120 and the third sheet 130 can also be formed by lamination. In the present disclosure, "lamination" can refer to the bonding of two different sheets by making at least one of the faces facing each other of two different sheets include a pattern formed by an adhesive resin. For example, it can be that there is a pattern formed by a semi-hardened adhesive resin on one of the two faces facing each other of two different sheets, and the other face is contacted on the pattern and then bonded by complete hardening. In addition, for example, the two faces facing each other of two different sheets can be formed by a semi-hardened adhesive resin, and they are bonded by complete hardening after contacting each other. The optical film 100 in a laminated form can provide a backlight unit that is thinner and has excellent shielding performance than the embodiment in which it is simply stacked without lamination.

[0065] The multiple pyramid (or quadrangular pyramid) patterns of the first sheet 110 can refract and / or reflect the light transmitted from the light source 11 and transmit it to the second sheet 120. The second sheet 120 can be formed in a form in which multiple prisms (or triangular prisms) extend in the width direction (X-axis direction) of the liquid crystal display device 1 and protrude in the height direction (Z-axis direction). The second sheet 120 can transmit the light passing through the first sheet 110 to the third sheet 130. The third sheet 130 can be formed in a form in which multiple prisms (or triangular prisms) extend in the length direction (Y-axis direction) of the liquid crystal display device 1 and protrude in the height direction (Z-axis direction). The third sheet 130 can transmit the light passing through the second sheet 120 toward the liquid crystal panel 20. The light incident from the light source 11 to the optical film 100 is diffused and / or focused while sequentially passing through the first sheet 110, the second sheet 120 and the third sheet 130, thereby having the advantages of not only ensuring the shielding performance of the shape of shielding the light source 11 but also ensuring high brightness performance. Figures 1 to 3 In the illustrated embodiment, the multiple prism patterns of the second sheet 120 extend in the width direction (X-axis direction) of the liquid crystal display device 1, and the multiple prism patterns of the third sheet 130 extend in the length direction (Y-axis direction) of the liquid crystal display device 1, but it is not necessarily limited to this, and differently, the multiple prism patterns of the second sheet 120 may also extend in the length direction (Y-axis direction) of the liquid crystal display device 1, and the multiple prism patterns of the third sheet 130 may also extend in the width direction (X-axis direction) of the liquid crystal display device 1. However, the multiple prism patterns of the second sheet 120 and the multiple prism patterns of the third sheet 130 only need to be orthogonal to each other. Refer again to Figure 1 The pyramid pattern layer 111 of the first sheet 110 may include a bottom surface including a first direction length a and a second direction length b, a height h, four side surfaces 111-1, 111-2, 111-3, 111-4 and a bottom surface having a vertex angle A and a vertex angle B (hereinafter, Figure 4A The size of the pyramid pattern can be set differently according to the embodiment.

[0066] Below, refer to 4A to 4F The optical film 100 will be described in more detail.

[0067] Figure 4A is a cross-sectional view showing an optical film according to an embodiment. Figure 4B is a cross-sectional view showing an optical film according to an embodiment. Figure 4C is a cross-sectional view showing an optical film according to an embodiment. Figure 4D is a diagram showing a pyramid pattern and a prism pattern according to an embodiment. Figure 4E FIG. 1 is a diagram showing a state where a pyramid pattern layer before being stacked according to an embodiment is viewed from above. Figure 4FFIG. 1 is a diagram showing a pyramid pattern layer in a stacked state according to an embodiment when viewed from above.

[0068] Reference FIG. 4A to FIG. 4C According to an embodiment of the present disclosure, the optical film 100 may include an optical film 100a including a first sheet 110, an optical film 100b including the first sheet 110 and the second sheet 120, and an optical film 100c including the first sheet 110, the second sheet 120 and the third sheet 130. For example, the first sheet 110 may be used alone as a constituent element of the optical film 100a without other sheets (e.g., the second sheet 120 and the third sheet 130). According to the present disclosure, the second sheet 120 and / or the third sheet 130 also include the first sheet 110, thereby providing an optical film having excellent shielding performance against light sources and excellent brightness performance. In the following, unless otherwise specified, for the convenience of description, the optical film may be used as follows: Figure 4C The optical film 100c is used as an example to describe in detail the various components included in the optical film 100. According to one embodiment, it should be noted that not only the optical films of the three sheets 110, 120, and 130 (for example: Figure 4C The optical film 100c), and the optical film of a sheet 110 (for example: Figure 4A The optical film 100a) and the optical films of the two sheets 110 and 120 (for example: Figure 4B Optical films 100b) may also be included within the scope of the present disclosure.

[0069] Reference Figure 4CThe first sheet 110, the second sheet 120 and the third sheet 130 of the optical film 100 (for example, the optical film 100c) may include a first base portion 112, a second base portion 122 and a third base portion 132, respectively. At this time, the first base portion 112, the second base portion 122 and the third base portion 132 may be composed of a transparent material that can transmit light (for example, a polycarbonate-based, polysulfone-based, polyacrylate-based, polystyrene-based, polyvinylchloride-based, polyvinyl alcohol-based, polynorbornene-based, polyester-based material). Specifically, for example, the first base portion 112, the second base portion 122, and / or the third base portion 132 may be made of polyethylene terephthalate (PET) or polyethylene naphthalate. The first base portion 112, the second base portion 122, and the third base portion 132 may be, for example, PET having a thickness of about 10 to about 50 μm, and more specifically, may be PET having a thickness of about 24 to about 40 μm. Fig. 6A In the various experimental examples including the field angle distribution described later in the following drawings, the case where the first base portion 112, the second base portion 122, and the third base portion 132 are PET with a thickness of 24 μm can be used as an example. However, it should be noted that the thickness of the first base portion 112, the second base portion 122, and the third base portion 132 is not limited to the example.

[0070] As before Figure 1 As described in the embodiment of the present invention, the first sheet 110 may include a pyramid pattern 111a in the form of a quadrangular pyramid corresponding to the first direction length a and the second direction length b, the height h, the pitch P, and the four side surfaces 111-1, 111-2, 111-3, and 111-4 forming the vertex angle A and the vertex angle B formed on the first surface 112a of the first base portion 112. The optical film 100 may include a plurality of pyramid patterns 111a having a plurality of columns in the first direction and a plurality of rows in the second direction perpendicular to the first direction.

[0071] Refer to Figure 4A and Figure 4DAccording to one embodiment, the pyramid pattern 111a may be an intaglio pattern. The pyramid pattern 111a may represent an intaglio pattern of a groove that regularly forms a quadrangular pyramid shape, and may be defined by the four side surfaces 111-1, 111-2, 111-3, and 111-4. Here, the four side surfaces may be triangular shapes that are the same or different from each other, and the sizes of the vertex angles A and B may be set according to the transverse length a, the longitudinal length b, and the height of each cross section of the pyramid pattern 111a. According to one embodiment, the vertex angles A and B may form substantially the same angle, and thus, the transverse length a and the longitudinal length b of the pyramid pattern 111a may also be set to be substantially the same. Here, the vertex angles A and B being substantially the same may mean that the vertex angles A and B have the same value within a process deviation (e.g., about 10%).

[0072] In addition, in the pyramid pattern 111a, the height h and the pitch P may be set based on the vertex angle C. The optical film 100 includes the pyramid pattern 111a having a triangular or trapezoidal vertical cross section parallel to the height direction (Z-axis direction), and the vertex angle C may be defined as an angle between two mutually facing sides of the four sides of the pyramid pattern 111a.

[0073] According to one embodiment, in the pyramid pattern 111a, the vertex angle C can be defined to be greater than 60° and less than 160°. For example, the vertex angle C can be 90°. Within the specified range, the larger the vertex angle C of the pyramid pattern 111a, the larger the angle θ (theta) (hereinafter, may be referred to as "incident angle θ") of light incident on the second sheet 120 can be. For example, in the optical film of the present disclosure including three sheets (e.g., optical film 100c), the first sheet 110 including the pyramid pattern 111a can play a role in allowing light incident on the second sheet 120 and the third sheet 130 to be incident at an optimal angle to increase brightness. The relationship between the constituent elements of the optical film and the brightness will be described through Figure 5A , Figure 5B The following examples will be described in more detail below.

[0074] According to an embodiment, the pyramid pattern 111 a may also be formed as a relief pattern.

[0075] Figure 4E The pyramid pattern layer before the first sheet 110 is laminated to the second sheet 120 may be shown, and Figure 4F The pyramid pattern layer may be shown in a state where the first sheet 110 is peeled off from the second sheet 120 after the first sheet 110 and the second sheet 120 are stacked. Figure 4E, the pyramid pattern layer 111 before stacking may include a first partition wall 111-5 dividing the boundary between the first side 111-1 and the fourth side 111-4, and include a second partition wall 111-6 dividing the boundary between the second side 111-2 and the third side 111-3. The first partition wall 111-5 and the second partition wall 111-6 may be the highest parts in the first sheet 110. According to one embodiment, although the first partition wall 111-5 is formed to be parallel to the first direction and the second partition wall 111-6 is formed to be parallel to the second direction, it should be noted that it is not necessarily limited to this. Referring to Figure 4F When the pyramid pattern layer 111 located on the upper surface of the first sheet 110 is stacked on the back surface of the second sheet 120 (for example, the first diffusion layer 123 on the back surface of the second sheet 120), the ends of the first partition wall 111-5 and the second partition wall 111-6 located at the uppermost end of the pyramid pattern layer 111 can be pressed. As a result, the tip of the first partition wall 111-5 can be deformed to form a first plane portion 111-7 having a predetermined width W1, and the tip of the second partition wall 111-6 can be deformed to form a second plane portion 111-8 having a predetermined width W2. According to one embodiment, the width W1 of the first plane portion 111-7 and the width W2 of the second plane portion 111-8 can be substantially the same.

[0076] According to various embodiments of the present disclosure, by including the pyramid pattern layer 111, light in four facet directions of the peripheral portion can be controlled. The pyramid pattern layer 111 according to an embodiment of the present disclosure may include a pyramid pattern 111a having a vertex angle of 90 degrees or more and 130 degrees or less, which is an angle between two triangles facing each other. According to an embodiment, when the vertex angle of the pyramid pattern 111a is formed to be at least 90 degrees, the pyramid pattern 111a can be formed to be as shown in FIG. Fig. 6A The shielding performance is satisfied as shown, and when the vertex angle is below it, the hot spot visibility (HSV; hotspot visibility) of the light source 11a can be increased.

[0077] The pyramid pattern layer 111 may be composed of a plurality of pyramid patterns and may be regularly arranged on the first surface 112a of the first sheet 110. A first prism pattern layer 113 including a plurality of first prism patterns may be formed on the second surface 112b of the first base portion 112. The first prism pattern layer 113 may be substantially the same as the second prism pattern layer 121 disposed in the second sheet 120 and the third prism pattern layer 131 disposed in the third sheet 130, except for the arrangement direction.

[0078] The second sheet 120 may include a second prism pattern layer 121 on which a plurality of second prism patterns extending in parallel to the width direction (or length direction) of the liquid crystal display device 1 are formed on the first surface 122a of the second base portion 122. The cross section of the second prism pattern layer 121 may be triangular. For example, the plurality of second prism patterns included in the second prism pattern layer 121 may be formed with a pitch of c and a height of d. The third sheet 130 may include a third prism pattern layer 131 on which a plurality of third prism patterns extending in parallel to the length direction (or width direction) of the liquid crystal display device 1 are formed on the first surface 132a of the third base portion 132. The cross section of the prism pattern formed in the third prism pattern layer 131 may be triangular. For example, the plurality of third prism patterns formed in the third prism pattern layer 131 may be formed with a pitch of e and a height of f. Here, the multiple second prism patterns included in the second prism pattern layer 121 and the multiple third prism patterns included in the third prism pattern layer 131 can extend in directions orthogonal to each other and be formed to have the same pitch and height respectively, but are not necessarily limited to this and can be changed in various ways according to the embodiment.

[0079] The first diffusion layer 123 may be included in the second surface 122b of the second base portion 122 of the second sheet 120, and the second diffusion layer 133 may be included in the second surface 132b of the third base portion 132 of the third sheet 130. The first diffusion layer 123 and the second diffusion layer 133 may be manufactured using any treatment method to increase turbidity, including a matte treatment to increase turbidity by making the first diffusion layer 123 and the second diffusion layer 133 respectively have rough surfaces, and a bead treatment to increase turbidity by using beads of glass, polymer, etc. Fig. 8A In various experimental examples including the viewing angle distribution described later in the following drawings, a case where the first diffusion layer 123 has a haze value of 3% and the second diffusion layer 133 has a haze value of 40% can be cited as an example.

[0080] The first sheet 110 and the second sheet 120 may be connected in a form in which the pyramid pattern layer 111 of the first sheet 110 and the first diffusion layer 123 of the second sheet 120 are stacked on each other, and the second sheet 120 and the third sheet 130 may be connected in a form in which the second prism pattern layer 121 of the second sheet 120 and the second diffusion layer 133 of the third sheet 130 are stacked on each other. At this time, the first diffusion layer 123 and the second diffusion layer 133 may each be formed of a binder (e.g., a bonding resin) with a matte pattern, for example, and may be manufactured by first laminating a sheet in a substantially 50% hardened state (e.g., a semi-hardened state) that is not 100% hardened to the other sheet and then stacking on the other sheet by 100% hardening.

[0081] Figure 5A The configuration of an experiment for measuring the brightness of an optical film according to an embodiment is shown. Figure 5B is a diagram showing an optimal incident angle for improving light distribution and brightness according to an embodiment. Figure 5B In the figure, the field angle distribution can represent the distribution of images formed on a horizontal plane (for example, a plane parallel to the XY plane).

[0082] Reference Figure 5A , the composition of the experiment for brightness measurement may include an optical film 100 and a light measuring device 210. Here, the optical film 100 may represent a situation where the second sheet 120 and the third sheet 130 are joined, and the first sheet 110 may be omitted from the illustration. The light measuring device 210 may be, for example, a high-speed spectrophotometric measurement system such as a colorimeter. Although not shown, a backlight unit including a light source may be arranged at the opposite side of the light measuring device 210 with the optical film 100 as a reference.

[0083] like Figure 5A As shown in FIG. 1 , the light measuring device 210 can measure the light incident in the height direction (Z-axis direction) of the optical film 100. In addition, the light distribution can be calculated using the bidirectional scattering distribution function (BSDF). Figure 5B As shown in the figure. At this time, in order to obtain high brightness for the liquid crystal display device 1, in the field angle data measured in the light measuring device 210, the brightness near the "light measuring device reference 0 degrees" parallel to the Z axis as the direction in which the light measuring device 210 is facing needs to be high, and it is known from the experimental results that the brightness near 0 degrees becomes the maximum when the light passing through the second sheet 120 and the third sheet 130 in the optical film 100 is incident at a specific angle. That is, the brightness of the liquid crystal display device 1 can be maximized when the light passing through the lower surface of the bonded body of the second sheet 120 and the third sheet 130 (for example: the second surface 122b of the second sheet 120) is incident at a specific incident angle θ. Here, the incident angle θ can represent the angle formed by the center light of the light (or light beam) emitted from the first sheet 110 with the normal line (normalline) to the second surface 122b of the second sheet 120 as the reference.

[0084] For example, refer to Figure 5BIn one embodiment (Example 1-1), in an embodiment in which the second base portion 122 and the third base portion 132 respectively have a thickness of 24 μm, when the pitch c of the prism pattern of the second prism pattern layer 121 formed on the first surface 122a of the second base portion 122 is formed to be 50 μm and the height d is formed to be 25 μm, the first diffusion layer 123 formed on the second surface 122b of the second base portion 122 has a haze value of 3%, the pitch e of the prism pattern of the third prism pattern layer 131 formed on the first surface 132a of the third base portion 132 is formed to be 50 μm and the height f is formed to be 25 μm, and the second diffusion layer 133 on the second surface 132b of the third base portion 132 has a haze value of 40%, the optimal incident angle θ at which the brightness near the reference 0 degree of the light measuring device becomes the highest can be formed to be 65 degrees. That is, when light passing through the lower surface of the bonded body of the second sheet 120 and the third sheet 130 (eg, the other surface 122 b of the second sheet 120 ) is incident at an angle of +65 degrees (or −65 degrees), it can have the highest brightness value.

[0085] In addition, for example, refer to Figure 5B In one embodiment (Example 1-2), in an embodiment in which the second base portion 122 and the third base portion 132 respectively have a thickness of 24 μm, when the pitch c of the prism pattern of the second prism pattern layer 121 formed on the first surface 122a of the second base portion 122 is formed to 45 and 55 μm and the height d is formed to 22.5 and 22.7 μm, the first diffusion layer 123 formed on the second surface 122b of the second base portion 122 has a haze value of 15%, the pitch e of the prism pattern of the third prism pattern layer 131 formed on the first surface 132a of the third base portion 132 is formed to 50 μm and the height f is formed to 25 μm, and the second diffusion layer 133 on the second surface 132b of the third base portion 132 has a haze value of 30%, the optimal incident angle θ at which the brightness near the reference 0 degree of the light measuring device becomes the highest can be formed to 73 degrees. That is, when light passing through the lower surface of the bonded body of the second sheet 120 and the third sheet 130 (eg, the other surface 122 b of the second sheet 120 ) is incident at an angle of +73 degrees (or −73 degrees), it can have the highest brightness value.

[0086] In summary, the incident angle θ of the light incident on the second sheet 120 may be determined according to the specifications and / or ridge directions of the plurality of second prism patterns of the second prism pattern layer 121 included in the second sheet 120 (for example: Figure 1The angle of incidence θ can be determined by the specifications and / or ridge directions (for example: P3) of the third prism pattern layer 131 included in the third sheet 130. That is, the incident angle θ can be set in a variety of ways according to the required specifications of the second sheet 120 and / or the third sheet 130 required in the optical film 100, and the optical film 100 of the present disclosure includes a prism pattern layer 113 having a prism pattern on its lower surface with the first base portion 112 as a reference and includes a pyramid pattern layer 111 having a pyramid pattern on its upper surface, thereby forming a light path corresponding to the optimal incident angle θ required in the optical film 100 according to a specific embodiment, and as a result, an optical film 100 with high brightness can be provided. In addition, referring to Figure 5B , which shows the field of view angle Ф(phi), which can be expressed from Figure 5B The angle formed by the imaginary line drawn from the center of the field angle distribution to one side (e.g., in a direction parallel to the X-axis) and the central light of the light (or light beam) emitted from the first sheet 110. The field angle (Φ, phi) is determined according to the specifications and / or ridge direction (e.g., Figure 1 of P1) to determine, and in Figure 5B In the two embodiments (Example 1-1, Example 1-2) shown, the optimal viewing angle Φ is set to 45 degrees. Fig. 6A and Figure 6B The embodiment of the present invention provides a more detailed description of the field of view angle Φ.

[0087] According to various embodiments of the present disclosure, an optical film 100 can be provided, including a first sheet 110 designed to improve its shielding performance in the direction of light incidence while allowing light passing through the lower surface of the joint of the second sheet 120 and the third sheet 130 (for example: the second surface 122b of the second sheet 120) to be incident at a specific incident light angle θ.

[0088] As reference Figures 1 to 5BAccording to an embodiment, the optical film 100 may include a first sheet 110 including a first base portion 112, a pyramid pattern layer 111 having a plurality of pyramid patterns formed on a first surface 112a of the first base portion 112, and a first prism pattern layer 113 having a plurality of first prism patterns formed on a second surface 112b of the first base portion 112. The optical film 100 may include a first sheet 110 which is arranged overlappingly above the first sheet 110 and includes a second base portion 122, having a plurality of first prism patterns formed on a first surface 122a of the second base portion 122. The present invention can include a second sheet 120 including a second prism pattern layer 121 having a second prism pattern, and a first diffusion layer 123 formed on the second surface 122b of the second base portion 122, and can include a third sheet 130 which is overlapped and arranged above the second sheet 120 and includes a third base portion 132, a third prism pattern layer 131 having a plurality of third prism patterns formed on the first surface 132a of the third base portion 132, and a second diffusion layer 133 formed on the second surface 132b of the third base portion 132.

[0089] exist Figures 1 to 5B In the liquid crystal display device 1, the first sheet 110, the second sheet 120 and the third sheet 130 can be manufactured in a stacked form. In particular, when the specifications of the pyramid pattern layer 111 formed on the first surface 112a of the first base portion 112 of the first sheet 110 and the first prism pattern layer 113 formed on the second surface 112b are appropriately adjusted in consideration of the specifications of the stacked second sheet 120 and the third sheet 130, light can be refracted and / or reflected so that the light is incident toward the second sheet 120 at a specific incident light angle θ at a location in contact with the second surface 122b of the second sheet 120 (improvement in brightness performance).

[0090] Fig. 6A is a diagram illustrating a backlight unit including a sheet formed with an inverted prism pattern layer (first prism pattern layer) according to a certain embodiment and an edge type light source. Figure 6B Graph showing the changes in the incident angle and the viewing angle corresponding to the changes in the refractive index of the inverted prism pattern layer. Fig. 6A and Figure 6B The embodiment can be observed according to the change of the refractive index of the inverted prism pattern layer to set Figure 5B The incident angle and field angle Φ are shown.

[0091] According to a specific embodiment, Fig. 6A As shown, a first sheet 110' excluding a pyramid pattern layer including a plurality of pyramid patterns and having a first prism pattern layer including a plurality of first prism patterns formed on a second surface may be provided. Figure 6B In the output light project, Fig. 6AIn the illustrated embodiment, the optical characteristics of the light emitted from the light guide plate 12 are measured between the light guide plate 12 and the first sheet 110 ′, which may represent data related to the optical characteristics of the light emitted from the light guide plate 12 . Figure 6B The various embodiments (Example 2-1, Example 2-2, Example 2-3) of the present invention may represent data related to the optical characteristics of light measured from above the first sheet 110'.

[0092] Reference Fig. 6A and Figure 6B , the arrangement direction of the ridge lines of the plurality of first prism patterns (e.g., P1) may be perpendicular to the arrangement of the light source (e.g., arranged in a fourth direction parallel to the X-axis). According to a specific embodiment, it can be confirmed that as the refractive index of the prism pattern layer disposed in the first sheet 110' changes, the incident angle θ to the second surface 122b of the second sheet 120 is maintained at approximately 73 degrees, and the field of view angle Φ changes according to the change in the refractive index of the first prism pattern layer. For example, when the refractive index of the first prism pattern layer is 1.49, the incident angle to the second surface 122b of the second sheet 120 may be formed to +74 degrees (or -74 degrees), and the field of view angle may be formed to 60 degrees. For another example, when the refractive index of the first prism pattern layer is 1.58, the incident angle to the second surface 122b of the second sheet 120 may be formed to +72 degrees (or -72 degrees), and the field of view angle may be formed to 54 degrees. For another example, when the refractive index of the first prism pattern layer is 1.69, the incident angle to the second surface 122b of the second sheet 120 can be formed to +73 degrees (or -73 degrees), and the viewing angle is formed to 53 degrees. That is, when the refractive index of the first prism pattern layer is adjusted, the viewing angle Φ of the light incident to the second surface 122b of the second sheet 120 can be adjusted to a desired angle. Using the principle described above, the specifications of the pyramid pattern layer 111 and the first prism pattern layer 113 provided in the first sheet can be set in a variety of ways so that the optical film 100 can exert the best brightness performance.

[0093] Figure 7 is a perspective view showing a liquid crystal display device including an optical film according to an embodiment. Fig. 8A is a graph showing optical characteristics associated with a liquid crystal display device including a diffusion plate according to a specific embodiment. Figure 8B is a diagram showing optical characteristics associated with a liquid crystal display device including an optical film according to an embodiment. Figure 8C is a diagram showing optical characteristics associated with a liquid crystal display device including an optical film according to an embodiment.

[0094] According to a specific embodiment, Fig. 6AAs shown, a first sheet 110 including a pyramid pattern layer including a plurality of pyramid patterns on a first surface and a first prism pattern layer including a plurality of first prism patterns on a second surface may be provided. Figures 1 to 5B The above description. Fig. 8A In the “diffuser plate”, the item can represent the Figure 7 The optical characteristics and data related thereto (e.g., viewing angle distribution 1, viewing angle distribution 2, brightness, incident angle θ, viewing angle Φ) of light measured between the optical sheet and the second sheet 120 and the light measured between the third sheet 130 and the diffuser 17 when an optical sheet to which light diffuser beads are added is arranged in place of the first sheet 110 in the liquid crystal display device 1. In addition, Figure 8B The items of various embodiments ("Example 3-1", "Example 3-2", "Example 3-3") may represent data related to optical characteristics (e.g., viewing angle distribution 1, viewing angle distribution 2, brightness, incident angle θ, viewing angle Φ) of light measured between the first sheet 110 and the second sheet 120 and light measured between the third sheet 130 and the diffuser sheet 17 when the refractive index DiffPY of the pyramid pattern layer 111 of the first sheet 110 and the refractive index DiffP of the first prism pattern layer 113 are changed in various ways. In addition, Figure 8C The items of various embodiments ("Example 3-4", "Example 3-5", "Example 3-6") may represent data related to optical characteristics of light measured between the first sheet 110 and the second sheet 120 and light measured between the third sheet 130 and the diffuser 17 when the refractive index DiffPY of the pyramid pattern layer 111 of the first sheet 110 and the refractive index DiffP of the first prism pattern layer 113 are changed in various ways (e.g., field of view angle distribution 1, field of view angle distribution 2, brightness, incident angle θ, field of view angle Φ). Field of view angle distribution 1 is used to represent the field of view for light emitted from the first sheet 110, which may represent the distribution of light formed on a horizontal plane (e.g., a plane parallel to the XY plane) at a location between the first sheet 110 and the second sheet 120. The viewing angle distribution 2 is used to represent the viewing angle of light emitted from the entire optical film 100, which can represent the distribution of light formed on a horizontal plane (eg, a plane parallel to the XY plane) between the third sheet 130 and the diffuser 17. Fig. 8A , Figure 8B as well as Figure 8C It can be confirmed that when the refractive index DiffPY of the pyramid pattern layer 111 and the refractive index DiffP of the first prism pattern layer 113 of the first sheet 110 are changed in various ways, the brightness, the incident angle, and / or the viewing angle are changed in various ways.

[0095] observe Figure 8BIn various embodiments ("Example 3-1", "Example 3-2", "Example 3-3"), as shown in Example 3-2, when the refractive index DiffPY of the pyramid pattern layer 111 of the first sheet 110 and the refractive index DiffP of the first prism pattern layer 113 are 1.58 and 1.49 respectively, Fig. 8A Compared with the embodiment with a diffuser, the brightness is 125.2%, which confirms that the brightness performance is improved. In addition, compared with the case where the refractive index DiffPY of the pyramid pattern layer 111 of the first sheet 110 and the refractive index DiffP of the first prism pattern layer 113 are set as shown in Example 3-1 or Example 3-3, it can be confirmed that the highest brightness improvement effect is achieved.

[0096] observe Figure 8C In various embodiments ("Example 3-4", "Example 3-5", "Example 3-6"), as shown in Example 3-5, when the refractive index DiffPY of the pyramid pattern layer 111 of the first sheet 110 and the refractive index DiffP of the first prism pattern layer 113 are 1.58 and 1.69 respectively, Fig. 8A Compared with the embodiment with a diffuser, the brightness is 120.6%, which confirms that the brightness performance is improved. In addition, compared with the case where the refractive index DiffPY of the pyramid pattern layer 111 of the first sheet 110 and the refractive index DiffP of the first prism pattern layer 113 are set as shown in Example 3-4 or Example 3-6, it can be confirmed that the highest brightness improvement effect is achieved.

[0097] According to various embodiments, the difference in refractive index between the pyramid pattern layer 111 and the first prism pattern layer 113 of the first sheet 110 may be formed such that |DiffP−DiffPY| is less than or equal to 0.2 at most. Figure 8B and Figure 8C When the absolute value of the difference in refractive index between the pyramid pattern layer 111 and the first prism pattern layer 113 is set to be 0.2 or less, the brightness of light emitted from the first sheet 110 can be increased.

[0098] According to various embodiments, the absolute value of the difference in refractive index between the pyramid pattern layer 111 and the first diffusion layer 123 may be formed to be 0.2 or less. By forming the refractive index of the pyramid pattern layer 111 and the first diffusion layer 123 to have a difference of 0.2 or less, when the first sheet 110 and the second sheet 120 are bonded, the pyramid pattern 111a formed on the first sheet 110 located at the lower side is prevented from being damaged, so as to minimize the deformation of the light separation characteristics and the light distribution, thereby facilitating the maintenance of the optimal incident angle θ incident on the second sheet 120 arranged at the upper side.

[0099] According to various embodiments, the refractive index difference between the second prism pattern layer 121 and the second diffusion layer 133 may be formed to be greater than 0 and less than 0.2. By making the refractive index difference between the second prism pattern layer 121 and the second diffusion layer 133 greater than 0 and less than 0.2, the optical film 100 may have high brightness.

[0100] As an example of the above-mentioned refractive index, the optical film 100 (eg, Figure 4C The optical film 100c) may include a first sheet 110 formed as a first prism pattern layer 113 having a refractive index of 1.49 and a pyramid pattern layer 111 having a refractive index of 1.49 to 1.69, a second sheet 120 formed as a first diffusion layer 123 having a refractive index of 1.49 and a second prism pattern layer 121 having a refractive index of 1.69, and a third sheet 130 formed as a second diffusion layer 133 having a refractive index of 1.49 and a third prism pattern layer 131 having a refractive index of 1.69. According to an embodiment, in a state where the refractive indexes of other constituent elements are fixed, the refractive index of the first prism pattern layer 113 including the inverted prism pattern is appropriately adjusted in accordance with the refractive index of the third prism pattern layer 131 including the uppermost prism, thereby forming an optimal incident light θ for light incident on the lower surface of the second sheet.

[0101] Fig. 9A is a diagram showing optical characteristics associated with a liquid crystal display device including an optical film according to an embodiment. Fig. 9B is a diagram showing optical characteristics associated with a liquid crystal display device including an optical film according to an embodiment. Fig. 9C is a diagram showing optical characteristics associated with a liquid crystal display device including an optical film according to an embodiment. Fig.9D is a diagram showing optical characteristics associated with a liquid crystal display device including an optical film according to an embodiment.

[0102] 9A to 9DAn embodiment may represent data related to optical characteristics of light measured between the first sheet 110 and the second sheet 120 and light measured between the third sheet 130 and the diffuser 17 (for example: field of view angle distribution 1, field of view angle distribution 2, brightness, left / right incident angle θ, left / right field of view angle Φ) when the refractive index DiffPY of the pyramid pattern layer 111 and the refractive index DiffP of the first prism pattern layer 113 of the first sheet 110 are constantly maintained (for example: the refractive index DiffPY of the pyramid pattern layer 111 and the refractive index DiffP of the first prism pattern layer 113 of the first sheet 110 are set to 1.49 and 1.49, respectively) and the ridge line direction P3 of a plurality of third prism patterns included in the third prism pattern layer 131 of the third sheet 130 and the ridge line direction P1 of a plurality of first prism patterns included in the first prism pattern layer 113 of the first sheet 110 are set in a variety of ways. Viewing angle distribution 1 is used to represent the viewing angle of light emitted from the first sheet 110, which can represent the distribution of light formed on a horizontal plane (e.g., a plane parallel to the XY plane) at a location between the first sheet 110 and the second sheet 120. Viewing angle distribution 2 is used to represent the viewing angle of light emitted from the entire optical film 100, which can represent the distribution of light formed on a horizontal plane (e.g., a plane parallel to the XY plane) at a location between the third sheet 130 and the diffuser 17. Fig. 9A , Fig. 9B , Fig. 9C as well as Fig.9D It can be confirmed that when the refractive index DiffPY of the pyramid pattern layer 111 and the refractive index DiffP of the first prism pattern layer 113 of the first sheet 110 are variously changed, brightness, left / right incident angles, and / or left / right viewing angles are variously changed.

[0103] observe Fig. 9A It can be confirmed from the various embodiments ("Example 4-1", "Example 4-2", "Example 4-3", "Example 4-4") that when the ridge line directions (P3; third direction) of the multiple third prism patterns of the third prism pattern layer 131 are orthogonal to the arrangement direction (fourth direction) of the light source 11, and the ridge line directions (P1; first direction) of the multiple first prism patterns of the first prism pattern layer 113 are also orthogonal to the arrangement direction (fourth direction) of the light source 11 (i.e., when aligned with the third direction), the brightness reaches a maximum of 151.6%.

[0104] observe Fig. 9BIt can be confirmed from the various embodiments ("Example 4-5", "Example 4-6", "Example 4-7", "Example 4-8") that when the ridge line direction (P3; third direction) of the multiple third prism patterns of the third prism pattern layer 131 is inclined by 75 degrees relative to the arrangement direction (fourth direction) of the light source 11, and when the ridge line direction (P1; first direction) of the multiple first prism patterns of the first prism pattern layer 113 is inclined by 75 degrees relative to the arrangement direction (fourth direction) of the light source 11 (i.e., parallel to the third direction), the brightness reaches a maximum of 148.0%.

[0105] observe Fig. 9C It can be confirmed from the various embodiments ("Example 4-9", "Example 4-10", "Example 4-11", "Example 4-12") that when the ridge direction (P3; third direction) of the multiple third prism patterns of the third prism pattern layer 131 is inclined 60 degrees relative to the arrangement direction (fourth direction) of the light source 11, and when the ridge direction (P1; first direction) of the multiple first prism patterns of the first prism pattern layer 113 is inclined 60 degrees relative to the arrangement direction (fourth direction) of the light source 11 (i.e., parallel to the third direction), the brightness reaches a maximum of 132.7%.

[0106] observe Fig.9D It can be confirmed from the various embodiments ("Example 4-13", "Example 4-14", "Example 4-15", "Example 4-16") that when the ridge line direction (P3; third direction) of the multiple third prism patterns of the third prism pattern layer 131 is inclined 45 degrees relative to the arrangement direction (fourth direction) of the light source 11, and when the ridge line direction (P1; first direction) of the multiple first prism patterns of the first prism pattern layer 113 is inclined 45 degrees relative to the arrangement direction (fourth direction) of the light source 11 (i.e., parallel to the third direction), the brightness reaches a maximum of 121.8%.

[0107] According to one embodiment, by arranging the ridge line direction (P3; third direction) of the plurality of third prism patterns of the third prism pattern layer 131 to be inclined from the arrangement direction (fourth direction) of the light source 11, the moiré phenomenon can be prevented from occurring, and on the other hand, by configuring the optical film 100 so that the ridge line direction (P3; third direction) of the plurality of third prism patterns of the third prism pattern layer 131 and the ridge line direction (P1; first direction) of the plurality of first prism patterns of the first prism pattern layer 113 are substantially oriented in the same direction, high brightness performance can also be ensured. That is, according to the present disclosure, the ridge line direction P1 of the plurality of first prism patterns of the first prism pattern layer 113 can be parallel to the ridge line direction P3 of the plurality of third prism patterns of the third prism pattern layer 131.

[0108] According to an embodiment, not only the optical film 100 of the three sheets 110, 120, 130, but also the optical film of one sheet 110 (for example: Figure 4A The optical film 100a) and the optical films of the two sheets 110 and 120 (for example: Figure 4B Optical films 100b) may also be included within the scope of the present disclosure.

[0109] According to an embodiment of the present disclosure, in an optical film of a sheet 110 (for example: Figure 4A The moiré phenomenon can also be prevented in the optical film 100a). Fig. 10A 1 is a diagram showing a state of a liquid crystal panel corresponding to the arrangement of the first prism pattern layer 113 and the pyramid pattern layer 111 in one sheet 110 . Fig. 10B 1 is a diagram showing a state of a liquid crystal panel corresponding to an arrangement of a first prism pattern layer 113 and a pyramid pattern layer 111 according to an embodiment.

[0110] The moiré phenomenon may or may not easily occur as the values ​​of the parameters of the pyramid pattern 111 a of the pyramid pattern layer 111 and the prism pattern of the first prism pattern layer 113 and / or the arrangement of the patterns are changed in various ways.

[0111] For example, Fig. 10A and Fig. 10B As shown, if the pyramid pattern 111a of the pyramid pattern layer 111 and the prism pattern of the first prism pattern layer 113 are in an arranged state, the moiré phenomenon may also occur easily or may not occur depending on the difference in the numerical value of the parameter of the pyramid pattern 111a and the numerical value of the parameter of the prism pattern (hereinafter referred to as "parameter numerical difference"). Here, the parameter may be, for example, a parameter related to length, and at this time, the "parameter numerical difference" may, for example, represent the difference in the pitch of the pyramid pattern and the pitch of the prism pattern.

[0112] According to an embodiment of the present disclosure, the pyramid pattern layer 111 may include a plurality of pyramid patterns 111a having a first pitch pi1, and the first prism pattern layer 113 (or inverted prism pattern layer) may include a plurality of prism patterns having a second pitch pi2. Here, the first pitch pi1 of the pyramid pattern 111a may be defined as the length of the bases a1 and a2. The difference in the numerical values ​​of the patterns may represent the difference between the first pitch pi1 and the second pitch pi2.

[0113] In addition, when one base of the pyramid pattern 111a and the ridge direction of the prism pattern do not form 0 degrees or 90 degrees, but are inclined at a predetermined angle (for example, 30 degrees) or more, the difference in the numerical value of the pattern can be compared based on the 1-1th pitch pi1-1 corresponding to the length of the diagonal line of the pyramid pattern 111a, rather than the first pitch pi1 of the length of the base of the pyramid pattern 111a. Fig. 6A and Figure 6B In the embodiment, it can be shown that the moiré phenomenon occurs when (pi1-1) / 2, which is half the length of the diagonal line of the pyramid pattern 111a, is compared with the pitch pi2 of the prism pattern, instead of comparing the length of the base sides a1 and a2 of the pyramid pattern 111a with the pitch pi2 of the prism pattern.

[0114] For example, in Fig. 10A Moire occurs in the liquid crystal panel 20 shown in FIG. Fig. 10B No moiré occurs in the liquid crystal panel 20 shown. Fig. 10A 1 shows that when the pitch pi2 of the prism pattern is 21 μm, the base length of the pyramid pattern is 30 μm, and half the length of the diagonal line of the pyramid pattern is 21.21 μm, the moiré phenomenon occurs. Fig. 10B It shows that when the pitch pi2 of the prism pattern is 17 μm, the length of the base of the pyramid pattern is 30 μm, and half of the length of the diagonal of the pyramid pattern is 21.21 μm, the moiré phenomenon does not occur. It can be confirmed that when the length of a certain parameter of the pyramid pattern (for example: half of the length of the diagonal) is similar to the length of the pitch of the prism pattern, the moiré phenomenon occurs, and when it is not similar, the moiré phenomenon does not occur. The pitch relationship in which moiré does not occur in the optical film 100 is organized as follows. When it is desired that moiré does not occur in the optical film 100, the following formula 1 or formula 2 needs to be satisfied.

[0115] Formula 1

[0116]

[0117] Formula 2

[0118]

[0119] Here, n can be a natural number.

[0120] In a specific embodiment of the present disclosure, when the pitch of the pyramid pattern is similar to the pitch of the prism pattern, the “similar” may be, for example, when the two different pitches have the same value when the values ​​below the decimal point are removed based on micrometers (μm). Alternatively, the “similar” may be, for example, when the difference between the two different pitches is less than 3% of the entire pitch length of a certain pattern.

[0121] The optical films and backlight units including the optical films of the various embodiments of the present disclosure described above are not limited to the aforementioned embodiments and drawings, and a person skilled in the art in the technical field to which the present disclosure belongs can implement various substitutions, deformations and changes within the technical scope of the present disclosure.

Claims

1. An optical film comprising: A first sheet, the first sheet comprising a first base portion, a pyramid pattern layer having a plurality of pyramid patterns with a base length of a first pitch and a diagonal length of a 1-1th pitch formed on a first surface of the first base portion, and a first prism pattern layer having a plurality of first prism patterns with a base length of a second pitch formed on a second surface of the first base portion; a second sheet, the second sheet comprising a second base portion, a second prism pattern layer having a plurality of second prism patterns formed on a first surface of the second base portion, and a first diffusion layer formed on a second surface of the second base portion, the first diffusion layer being arranged above the first sheet facing and overlapping the pyramid pattern layer; as well as a third sheet, the third sheet comprising a third base portion, a third prism pattern layer having a plurality of third prism patterns formed on a first surface of the third base portion, and a second diffusion layer formed on a second surface of the third base portion, the second diffusion layer being arranged above the second sheet so as to face and overlap the third prism pattern layer, The plurality of first prism patterns have ridge lines formed toward a first direction, The plurality of pyramid patterns are configured such that an extending direction of one of the bases forms an angle of not less than 0 degrees and not more than 45 degrees with the first direction, The plurality of second prism patterns have ridge lines formed in a second direction perpendicular to the first direction, The plurality of third prism patterns have ridge lines formed toward a third direction perpendicular to the second direction.

2. The optical film according to claim 1, wherein The second sheet and the third sheet are manufactured in a stacked form.

3. The optical film according to claim 1, wherein The first sheet, the second sheet, and the third sheet are respectively manufactured in a stacked form.

4. The optical film according to claim 1, wherein The first sheet refracts or reflects light so that light having a specified angle is incident toward the second surface of the second sheet.

5. The optical film according to claim 1, wherein An absolute value of a difference between a refractive index of the pyramid pattern layer and a refractive index of the first prism pattern layer is formed to be 0.2 or less.

6. The optical film according to claim 1, wherein: The optical film satisfies the following formula 1 or formula 2: Formula 1 Formula 2 Herein, n represents a natural number, pi1 represents the first pitch, pi1-1 represents the 1-1th pitch, and pi2 represents the second pitch.

7. A backlight unit, comprising: Edge type light source; as well as an optical film, the optical film being arranged above the light source, The optical film comprises: A first sheet, the first sheet comprising a first base portion, a pyramid pattern layer having a plurality of pyramid patterns with a base length of a first pitch and a diagonal length of a 1-1th pitch formed on a first surface of the first base portion, and a first prism pattern layer having a plurality of first prism patterns with a base length of a second pitch formed on a second surface of the first base portion; a second sheet, the second sheet comprising a second base portion, a second prism pattern layer having a plurality of second prism patterns formed on a first surface of the second base portion, and a first diffusion layer formed on a second surface of the second base portion, the first diffusion layer being arranged above the first sheet facing and overlapping the pyramid pattern layer; as well as a third sheet, the third sheet comprising a third base portion, a third prism pattern layer having a plurality of third prism patterns formed on a first surface of the third base portion, and a second diffusion layer formed on a second surface of the third base portion, the second diffusion layer being arranged above the second sheet so as to face and overlap the third prism pattern layer, The plurality of first prism patterns have ridge lines formed toward a first direction, The plurality of pyramid patterns are such that an extending direction of one of the bases forms an angle of not less than 0 degrees and not more than 45 degrees with the first direction, The plurality of second prism patterns have ridge lines formed in a second direction perpendicular to the first direction, The plurality of third prism patterns have ridge lines formed toward a third direction perpendicular to the second direction.

8. The backlight unit according to claim 7, wherein: The edge-type light sources are arranged in a fourth direction perpendicular to the first direction, and are formed to irradiate light toward a direction parallel to the first direction.

9. The backlight unit according to claim 7, wherein: The edge-type light sources are arranged in a fourth direction, The first direction is inclined with respect to the fourth direction at a first angle difference, and the third direction is formed in parallel with the first direction and is inclined with respect to the fourth direction at a second angle difference which is the same as the first angle difference.

10. The backlight unit according to claim 7, wherein: The backlight unit has an optical film satisfying the following Formula 1 or Formula 2: Formula 1 Formula 2 Herein, n represents a natural number, pi1 represents the first pitch, pi1-1 represents the 1-1th pitch, and pi2 represents the second pitch.

11. An optical film comprising: a first base portion; a pyramid pattern layer, wherein the pyramid pattern layer is formed on the first surface of the first base portion with a plurality of pyramid patterns having a base length of a first pitch and a diagonal length of a 1-1th pitch; and a first prism pattern layer, wherein the first prism pattern layer is formed with a plurality of first prism patterns having a bottom length of a second pitch on the second surface of the first base portion, The plurality of first prism patterns have ridge lines formed toward a first direction, The plurality of pyramid patterns are configured such that an extending direction of one of the base sides forms an angle of not less than 0 degrees and not more than 45 degrees with the first direction.

12. The optical film according to claim 11, wherein An absolute value of a difference between a refractive index of the pyramid pattern layer and a refractive index of the first prism pattern layer is 0.2 or less.

13. The optical film according to claim 11, wherein: The optical film satisfies the following formula 1 or formula 2: [Formula 1] [Formula 2] Herein, n represents a natural number, pi1 represents the first pitch, pi1-1 represents the 1-1th pitch, and pi2 represents the second pitch.

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