Light control film, backlight unit, and display device

Abstract

To provide a light control film.SOLUTION: A light control film, backlight unit, and display device are provided. The light control film comprises: a louver film which includes a plurality of light absorption patterns arranged in parallel; a light transmitting portion surrounding at least a part of the plurality of light absorption patterns; a reflective polarizing film for polarization recycling, and configured to adjust the angle of light to be transmitted to the louver film; and a first adhesive layer disposed between the louver film and the reflective polarizing film.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] Various embodiments of the present disclosure relate to light control films, backlight units including the light control films, and display devices including the light control films. [Background technology]

[0002] As displays have developed, there has been a need to develop light-controlling films that prevent information displayed on the display from being revealed to others. For example, as the market for vehicle displays has grown, the use of vehicle displays has increased, and for the safety of the driver and passengers, light-controlling films that can control the viewing angle have been developed to prevent the driver from looking at the images displayed on the display while driving.

[0003] Generally, light control films can include louver films for the purpose of protecting privacy and / or limiting the viewing angle. Light control films can also include films configured to change light transmittance depending on the angle. Therefore, there is a demand for light control films that can improve the viewing angle and brightness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2004-514167 Summary of the Invention [Problem to be solved by the invention]

[0005] To reduce the viewing angle of the light control film, multiple optical sheets (e.g., two sheets) may be stacked. However, when using an optical film including multiple stacked optical sheets, the thickness of the optical film increases, and brightness may decrease due to a decrease in transmittance caused by the absorption layer of the optical film. Furthermore, battery power consumption may increase to compensate for the decrease in brightness. Furthermore, the assembly time of the backlight module may increase due to the stacking of optical sheets.

[0006] The present invention provides a highly transparent light control film using optical films with improved light recycling in reflective polarizing films and improved total reflection in louver films.

[0007] The present invention provides a light control film that adjusts the viewing angle and improves brightness by using an asymmetrically formed light-blocking pattern on a louver film.

[0008] The problems to be solved by the present disclosure are not limited to the above problems, but may be expanded in various ways without departing from the spirit and scope of the present disclosure. [Means for solving the problem]

[0009] A light control film according to various embodiments of the present disclosure may include a louver film including a plurality of light-absorbing patterns arranged side by side and a light-transmitting portion surrounding at least a portion of the plurality of light-absorbing patterns; a reflective polarizing film for polarization recycling configured to adjust the angle of light transmitted to the louver film; and a first adhesive layer positioned between the louver film and the reflective polarizing film. The difference between the first refractive index of the light-transmitting portion and the second refractive index of the plurality of light-absorbing patterns may be 0.05 or greater. The plurality of light-absorbing patterns may include first and second sides formed asymmetrically with respect to each other. [Effects of the Invention]

[0010] According to various embodiments of the present disclosure, a reflective polarizing film configured to enhance the total reflection of a louvered film can be used to provide an optical film with improved light transmission. The improved transmission of the optical film can increase energy efficiency and improve the brightness of display devices.

[0011] According to various embodiments of the present disclosure, the light control film allows a user to adjust the screen angle as needed. For example, a display device including the light control film of the present disclosure can be installed in a vehicle display and adjust the viewing angle to suit the driver's and passenger's field of view. As another example, the light control film can enhance the user's privacy.

[0012] The effects obtained by the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the following description. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 illustrates a display device according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a cross-sectional view of a light control film according to one embodiment of the present disclosure. [Figure 3] FIG. 1 is a cross-sectional perspective view of a backlight unit including a light control film according to one embodiment of the present disclosure. [Figure 4] FIG. 10 is a diagram showing the cut-off viewing angle versus the refractive index of the light-shielding pattern layer and adhesive layer according to one embodiment of the present disclosure. [Figure 5] FIG. 10 is a diagram comparing the characteristics of a display device including a light control film including a louver film and a reflective polarizing film according to one embodiment of the present disclosure with the characteristics of existing display devices. DETAILED DESCRIPTION OF THE INVENTION

[0014] The various embodiments of the present disclosure and the terms used therein are not intended to limit the technical features described herein to specific embodiments, but should be understood to include various modifications, equivalents, or alternatives of the embodiments. In connection with the description of the drawings, like reference numerals may be used for similar or related components. The singular form of a noun corresponding to an item may include one or more of the said item, unless otherwise specified in the relevant context.

[0015] According to various embodiments, each of the aforementioned components (e.g., modules or programs) may include one or more objects, and some of the multiple objects may be located separately in other components. According to various embodiments, one or more of the aforementioned components or operations may be omitted, or one or more other components or operations may be added. Alternatively, or additionally, multiple components (e.g., modules or programs) may be integrated into a single component. In such cases, the integrated component may perform one or more functions of each of the multiple components that are the same as or similar to those performed by the multiple components prior to integration. According to various embodiments, operations performed by a module, program, or other component may be performed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be performed in a different order, omitted, or one or more other operations may be added.

[0016] Various embodiments will be described below with reference to the accompanying drawings. In describing the present embodiments, the same components will be designated by the same names and reference numerals, and additional description thereof will be omitted. Furthermore, in describing the embodiments of the present invention, components having the same functions will be designated by the same names and reference numerals, but it should be noted that they are not substantially the same as those of the prior art.

[0017] In various embodiments, terms such as "comprise" or "have" should be understood to indicate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, without precluding the possible presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0018] FIG. 1 is a diagram illustrating a display device according to one embodiment of the present disclosure.

[0019] 1, a display device (or liquid crystal display device) 1 according to an embodiment of the present disclosure includes a backlight unit 10 and a liquid crystal panel 20. The backlight unit 10 includes a substrate 11 including a light source 11a, a color conversion sheet 13, an optical film 100, prism sheets 15 and 16, and a diffusion sheet 17. According to an embodiment, a reflective sheet 12 may be disposed on one surface of the light source 11a.

[0020] According to one embodiment, in the backlight unit 10, at least one of the components of FIG. 1 (e.g., the diffusion sheet 17) may be omitted, or one or more other components (e.g., a reflective polarizing sheet (not shown)) may be added.

[0021] According to one embodiment, the light source 11a is configured to radiate light toward the rear surface of the liquid crystal panel 20 and may be disposed on one surface of the substrate 11. The light source 11a may be a light-emitting diode (LED). The light source 11a may include, for example, a plurality of LED chips radiating light. Depending on the size of the LED chip, LEDs can be classified into large LEDs (chip size: 1,000 μm or more), medium LEDs (chip size: 300 to 500 μm), small LEDs (chip size: 200 to 300 μm), mini LEDs (chip size: 100 to 200 μm), and micro LEDs (chip size: 100 μm or less). Here, the LED may include materials such as InGaN and GaN. The light emitted from the light source 11a can radiate toward the liquid crystal panel 20 (Z-axis direction). The light emitted from the light source 11a can pass through the color conversion sheet 13 and enter the diffusion sheet .

[0022] According to one embodiment, a reflective sheet 12 may be disposed on the surface of the substrate 11. The reflective sheet 12 may include a material such as BaSO4, TiO2, CaCo3, SiO2, or Ca3(SO4)2, or may include a material such as Ag, and may be applied or coated on the substrate 11 between the light sources 11a. The reflective sheet 12 serves to reflect light emitted from the light source 11a, which is reflected toward the substrate 11 due to interface reflection or the like while passing through the color conversion sheet 13, the diffusion sheets 14 and 17, and the prism sheets 15 and 16, back in the direction of the emitted light. This minimizes light loss. In other words, the reflective sheet 12 can perform light recycling.

[0023] 1 shows light source 11a positioned on substrate 11, but the structure of backlight unit 10 of the present disclosure is not limited thereto. For example, a light control film of the present disclosure (e.g., light control film 400 of FIG. 2) can also be applied to a backlight unit (e.g., FIG. 3) that uses a light guide plate (e.g., light guide plate 19a of FIG. 3). In a backlight unit that includes light guide plate 19a, light source 11a is positioned on a side surface of light guide plate 19a, and light guide plate 19a can convert light incident from light source 11a into the form of a surface light source.

[0024] According to one embodiment, the color conversion sheet 13 can convert the color of the light emitted from the light source 11a. In one example, the light from the mini LED or micro LED may be blue light (450 nm). In this case, the blue light needs to be converted to white light. The color conversion sheet 13 can transmit the blue light emitted from the light source 11a while simultaneously converting the blue light to white light.

[0025] According to one embodiment, the diffusion sheets 14 and 17 can uniformly diffuse light incident from the color conversion sheet 13. The diffusion sheets 14 and 17 can contain a solution of a curable resin (e.g., a mixture of one or more selected from at least one of urethane acrylate, epoxy acrylate, ester acrylate, and radical-generating monomer) to which light diffusing beads have been added, thereby diffusing light through the light diffusing beads. In addition, the diffusion sheets 14 and 17 can be formed with a protrusion pattern (or protrusions) of uniform or non-uniform size and shape (e.g., spherical) to promote light diffusion.

[0026] According to one embodiment, the diffusion sheets 14, 17 may include a lower diffusion sheet 14 and an upper diffusion sheet 17. The lower diffusion sheet 14 may be disposed between the color conversion sheet 13 and the prism sheet 15. The upper diffusion sheet 17 may be disposed between the prism sheet 16 and the liquid crystal panel 20. When the backlight unit 10 further includes a reflective polarizer, the upper diffusion sheet 17 may be disposed between the prism sheet 16 and the reflective polarizer.

[0027] According to one embodiment, the prism sheets 15 and 16 can condense incident light using an optical pattern formed on their surface and then emit the light to the liquid crystal panel 20. The prism sheets 15 and 16 may include a translucent base portion and a prism pattern layer formed on the upper surface of the base portion (the surface facing the +Z-axis direction). The prism pattern layer may be formed as an optical pattern layer in the form of a triangular array having a predetermined angle (e.g., a 45° inclined surface) to enhance brightness in a plane parallel to a plane (e.g., the XY plane). The prism pattern of the prism pattern layer may be in the shape of a triangular prism, and one surface of the triangular prism may be disposed so as to face the base portion.

[0028] According to one embodiment, the prism sheets 15, 16 may include a first prism sheet 15 and a second prism sheet 16. According to one embodiment, the first prism sheet 15 and the second prism sheet 16 may be formed as a composite prism sheet structure. The second prism sheet 16 may be disposed on the upper surface of the first prism sheet 15 so as to overlap each other. In the first prism sheet 15, a plurality of first prism patterns may be arranged side by side. Each first prism pattern may have a structure extending in one direction. For example, each vertex line 15a of the first prism pattern may be formed to extend in the X-axis direction. Similarly, in the second prism sheet 16, a plurality of second prism patterns may be arranged side by side. Each second prism pattern may have a structure extending in one direction. For example, each vertex line 16a of the second prism pattern may be formed to extend in a direction perpendicular to the X-axis and Z-axis (hereinafter referred to as the "Y-axis"). Here, for convenience of explanation, the extension directions of the first prism pattern and the second prism pattern are shown facing the X-axis and Y-axis. However, this is not limited to the illustrated embodiment, and the vertex lines 16a may be oriented in a direction other than the X-axis or Y-axis.

[0029] According to one embodiment, a reflective polarizing sheet (not shown) is provided on top of the prism sheets 15, 16 and the upper diffusion sheet 17, and serves to transmit some polarized light and reflect other polarized light downward from the light collected by the prism sheets 15, 16 and diffused by the upper diffusion sheet.

[0030] According to one embodiment, the liquid crystal panel 20 can refract the light emitted from the light source 11a into a predetermined pattern in response to an electrical signal. The refracted light passes through a color filter and a polarizing filter disposed in front of the liquid crystal panel 20 to form a screen.

[0031] Figure 2 is a cross-sectional view of a light control film according to one embodiment of the present disclosure. Figure 3 is a cross-sectional perspective view of a backlight unit including a light control film according to one embodiment of the present disclosure.

[0032] 2 and / or 3, light control film 400 may include a louver film 410, a reflective polarizing film 420, an adhesive layer 430, a base film 440, a matte layer 450, and / or a coating layer 460. The configuration of light source 11a and diffusion sheet 19b in Fig. 3 may be the same as or replace all or part of the configuration of light source 11a and diffusion sheet 14 in Fig. 1.

[0033] According to one embodiment, the light source 11a can emit light from the side of the light guide plate 19a (for example, in the Y-axis direction) and transmit the light to the light guide plate 19a. By irradiating the light emitted from the light source 11a onto the back surface of the liquid crystal panel, a distinguishable screen can be realized.

[0034] According to an embodiment, the light source 11a may include one of a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp, and a light emitting diode (LED).

[0035] According to one embodiment, the reflector 18 is positioned behind the light guide plate 19a (e.g., in the -Z axis direction), and light emitted behind the light guide plate 19a can be reflected and incident on the light guide plate 19a, thereby reducing light loss.

[0036] According to one embodiment, the light guide plate 19a can convert the light incident from the light source 11a into the form of a surface light source.

[0037] According to one embodiment, the diffusion sheet 19b can uniformly diffuse light incident from the light guide plate 19a. As one example, the diffusion sheet 19b can be formed by applying a solution of a curable resin (e.g., a mixture of one or more selected from at least one of urethane acrylate, epoxy acrylate, ester acrylate, and radical-generating monomer) to which light diffusing beads have been added, thereby diffusing light through the light diffusing beads. As another example, the diffusion sheet 19b can be formed with a protrusion pattern (or protrusions) of uniform or non-uniform size and shape (e.g., spherical) to promote light diffusion.

[0038] According to one embodiment, the light control film 400 is disposed above the diffusion sheet 19b (for example, in the +Z-axis direction) and can collect the light transmitted from the diffusion sheet 19b and move it upward.

[0039] According to one embodiment, the light control film 400 can be disposed above (in the +Z-axis direction) a diffusion sheet (e.g., the lower diffusion sheet 14 in FIG. 1 ). The light control film 400 can collect light transmitted from the diffusion sheet 14 and move it upward. In one example, the light control film 400 includes a light-collecting louver film 410, which can internally totally reflect and refract the light transmitted from the diffusion sheet 14 upward. According to one embodiment, the light control film 400 may be referred to as an optical film.

[0040] According to one embodiment, the light control film 400 can collect at least a portion of the light generated from the light source 11a. For example, the light control film 400 can reduce and / or limit the viewing angle of the display device 1 by collecting light traveling in the left-right direction (e.g., the X direction) toward the center (e.g., the +Z axis direction). According to one embodiment, the light control film 400 may be referred to as an optical film.

[0041] According to one embodiment, the louver film 410 may include a plurality of light-absorbing patterns 411. According to one embodiment, the light-absorbing patterns 411 may have a material capable of absorbing at least a portion of light. For example, the light-absorbing patterns 411 may include at least one of materials capable of absorbing light, such as carbon nanotubes (CNTs), graphene, or carbon black. According to one embodiment, the louver film may be referred to as a microlouver film or a light-shielding pattern layer. According to one embodiment, the louver film 410 may include a light-transmitting portion 412 positioned between the plurality of light-absorbing patterns 411. The plurality of light-absorbing patterns 411 and the light-transmitting portion 412 may be arranged substantially alternately along the left-right direction (e.g., the X-axis direction). According to one embodiment, the light-absorbing pattern 411 may be referred to as a first pattern or a reflective pattern. The light-transmitting portion 412 may be referred to as a light-transmitting region or a transmissive layer, and may be distinguished from the base film 440, which is another component that transmits light.

[0042] According to one embodiment, the louver film 410 can be disposed between the first base film 441 and the first adhesive layer 431. For example, the louver film 410 can include a first surface 410a (e.g., a top surface) facing the first base film 441 and a second surface 410b (e.g., a back surface) opposite the first surface 410a and facing the reflective polarizing film 420.

[0043] According to one embodiment, the plurality of light absorbing patterns 411 can be designed to be arranged in corresponding shapes. For example, one light absorbing pattern 411 can extend along a first direction (e.g., the Y-axis direction). The plurality of light absorbing patterns 411 may be arranged spaced apart along a left-right direction (hereinafter referred to as a "second direction") (e.g., the X-axis direction). A structure in which the light absorbing pattern 411 extends along the first direction may be referred to as a structure in which one light absorbing pattern 411 is arranged substantially parallel to the first direction.

[0044] According to one embodiment, the light-absorbing pattern 411 may be disposed on the second surface 410b of the louver film 410. For example, the light-absorbing pattern 411 may include an upper surface 411d facing the first surface 410a, a lower surface 411c disposed on the second surface 410b, and side surfaces 411a and 411b extending from the lower surface 411c to the upper surface 411d. The lower surface 411c may be disposed on the same first plane (parallel to the XY plane) as the second surface 410b. According to one embodiment, the side surfaces 411a and 411b may include a first side surface 411a and a second side surface 411b.

[0045] According to one embodiment, the light-absorbing pattern 411 may be formed asymmetrically. For example, the inclination angles of the first side surface 411a and the second side surface 411b may be different. According to one embodiment, the first side surface 411a may be inclined at a first angle X1 with respect to the reflective polarizing film 420 and / or the second surface 410b. The second side surface 411b may be inclined at a second angle X2 different from the first angle X1 with respect to the reflective polarizing film 420 and / or the second surface 410b. For example, the first angle X1, at which the first side surface 411a forms a normal to the reflective polarizing film 420 and / or the second surface 410b, may be 3.5 degrees to 5 degrees. For example, the second angle X2, at which the second surface 411b forms a normal to the reflective polarizing film 420 and / or the second surface 410b, may be 0 degrees. That is, according to one embodiment, second side surface 411b may be substantially perpendicular to reflective polarizing film 420 and / or second surface 410b. Asymmetrically forming light-absorbing pattern 411 can change the path of light passing through louver film 410. For example, the angle (e.g., viewing angle) of the screen output from a display device including light control film 400 (e.g., display device 1 in FIG. 1) can be changed. Asymmetrically forming light-absorbing pattern 411 can increase the intensity of light totally reflected by louver film 410, thereby increasing the brightness of a display device including light control film 400 (e.g., display device 1 in FIG. 1).

[0046] According to one embodiment, the light absorbing pattern 411 may have a substantially asymmetric trapezoidal shape, for example, a wedge shape. According to one embodiment, the cross-sectional area of ​​the light absorbing pattern 411 in a second direction (for example, the X-axis direction) may be smaller toward a third direction (+Z-axis direction). For example, the area of ​​the lower surface 411c of the light absorbing pattern 411 may be larger than the area of ​​the upper surface 411d. When the area of ​​the lower surface 411c of the light absorbing pattern 411 is larger than the area of ​​the upper surface 411d, moire patterns and optical interference can be reduced.

[0047] According to one embodiment, the upper surface 411d of the light absorbing pattern 411 may be spaced apart from the first surface 410a of the louver film 410. By spacing the light absorbing pattern 411 apart from the first surface 410a of the louver film 410, it is possible to control the cut-off viewing angle brightness, thereby providing an improved light control film 400. According to one embodiment, the distance between the upper surface 411d of the light absorbing pattern 411 and the first surface 410a of the louver film 410 may be designed taking into consideration air bubbles generated during the manufacturing process of the light control film 400 and the amount of UV resin consumed.

[0048] According to one embodiment, the plurality of light-absorbing patterns 411 can change the viewing angle of light incident on the plurality of light-absorbing patterns 411. For example, the direction of light incident on the plurality of light-absorbing patterns 411 can be changed. For example, the louver film 410 uses light-absorbing patterns 411 that can concentrate or change the path of at least a portion of light incident from the bottom (e.g., in the -Z-axis direction) to the top (e.g., in the +Z-axis direction) of the louver film 410. In this disclosure, focusing of light can be interpreted as condensing.

[0049] According to one embodiment, louver film 410 may have a refractive index to improve total reflection. For example, the second refractive index of light-absorbing patterns 411 may be different from the first refractive index of light-transmitting portions 412. According to one embodiment, the difference between the first refractive index of light-transmitting portions 412 and the second refractive index of light-absorbing patterns 411 may be 0.05 or more. The transmission axis of louver film 410 may be arranged parallel to the width direction or horizontal direction (e.g., XY plane) of light control film 400.

[0050] According to one embodiment, the reflective polarizing film 420 can increase the brightness of the backlight unit 10 and / or the display device 1 using polarization recycling. For example, the reflective polarizing film 420 can transmit a portion of the light generated from the light source 11a and reflect another portion. According to one embodiment, the reflective polarizing film 420 can have a structure in which multiple layers with different refractive indices are alternately arranged. For example, the reflective polarizing film 420 can be an assembly in which a high refractive index layer and a low refractive index layer are stacked. According to one embodiment, the reflective polarizing film 420 may be referred to as a reflective polarizing sheet.

[0051] According to one embodiment, the reflective polarizing film 420 can adjust the angle of light transmitted to the louver film 410. For example, at least a portion of the light generated from the light source 11a can be refracted while passing through the reflective polarizing film 420 and / or the first adhesive layer 431. The reflective polarizing film 420 can refract the light at an angle to increase the intensity and / or amount of light incident on the path of the light for total reflection by the louver film 410.

[0052] According to one embodiment, the reflective polarizing film 420 can transmit light within a specified angular range and reflect at least a portion of light exceeding the specified angle. The specified angular range of light may be referred to as the angular range that induces total reflection in the louver film 410. By allowing the reflective polarizing film 420 to transmit light within the specified angular range, the total reflection efficiency of the louver film 410 can be improved. The specified angular range can be variably designed based on the design of the light control film 400 (e.g., the thickness of the reflective polarizing film 420, the material of the reflective polarizing film 420, the thickness of the first adhesive layer 431, the material of the first adhesive layer 431, and / or the configuration of the louver film 410 (e.g., the pitch of the light-absorbing pattern 411, the material of the light-transmitting portion 412)).

[0053] According to one embodiment, the reflective polarizing film 420 may include a transmission axis arranged parallel to the width direction or horizontal direction (e.g., XY plane) of the light control film 400. Light passing through the reflective polarizing film 420 may be transmitted to the louver film 410. According to one embodiment, the transmission axis of the reflective polarizing film 420 may be arranged substantially parallel to the polarizing film of the display device 1. For example, the reflective polarizing film 420 may include a transmission axis formed along a first direction (e.g., Y-axis direction).

[0054] According to one embodiment, the transmission axes of the configuration of the light control film 400 may be substantially parallel. For example, the light-absorbing pattern 411, the light-transmitting portion 412, and the reflective polarizing film 420 may extend along a horizontal transmission axis (e.g., the Y-axis direction). According to one embodiment, the transmission axis of the liquid crystal panel 20 may also be arranged substantially parallel to the transmission axis of the light control film 400. According to one embodiment, the multiple light sources 11a may be arranged along the transmission axis (e.g., the Y-axis direction). For example, the multiple light sources 11a may emit light in a direction perpendicular to the transmission axis.

[0055] According to one embodiment, the reflective polarizing film 420 can be disposed below (in the −Z axis direction) the louver film 410. For example, the reflective polarizing film 420 can be located between the first adhesive layer 431 and the second adhesive layer 432.

[0056] According to one embodiment, the adhesive layer 430 may include a first adhesive layer 431 disposed between the louver film 410 and the reflective polarizing film 420, and a second adhesive layer 432 disposed between the reflective polarizing film 420 and the second base film 442. According to one embodiment, the first adhesive layer 431 reduces an air gap between the louver film 410 and the reflective polarizing film 420, thereby reducing light loss due to interface reflection. The second adhesive layer 432 reduces an air gap between the reflective polarizing film 420 and the second base film 442, thereby reducing light loss due to interface reflection. According to one embodiment, the adhesive layer 430 may be referred to as an adhesive. According to one embodiment, the louver film 410 and the reflective polarizing film 420 may be bonded together using an adhesive layer (e.g., the first adhesive layer 431).

[0057] According to one embodiment, the base film 440 can support at least a portion of the configuration of the light control film 400. According to one embodiment, the base film 440 can include a first base film 441 that supports the matte layer 450 and a second base film 442 that supports the second adhesive layer 432. According to one embodiment, the first base film 441 can be disposed between the matte layer 450 and the louver film 410. According to one embodiment, the second base film 442 can be disposed between the second adhesive layer 432 and the coating layer 460. The second base film 442 can be disposed between the reflective polarizing film 420 and the coating layer 460.

[0058] According to one embodiment, the base film 440 (e.g., the first base film 441 and the second base film 442) may be formed of a material that can transmit at least a portion of visible light. According to one embodiment, the base film 440 may include at least one of polymer resins such as polycarbonate (PC), acrylate, and polyethylene terephthalate (PET). According to one embodiment, the first base film 441 may be referred to as a first light-transmitting layer. The second base film 442 may be referred to as a second light-transmitting layer.

[0059] According to one embodiment, a matte layer 450 may be provided to reduce the visibility of moire. For example, the matte layer 450 may include a plurality of protrusions facing the third direction (+Z-axis direction). According to one embodiment, the matte layer 450 may be disposed on the first base film 441. According to one embodiment, the plurality of protrusions of the matte layer 450 may enhance the appearance shielding of the light control film 400 and reduce the visibility of moire.

[0060] According to one embodiment, the mat layer 450 may achieve a scattering effect by using non-bead type surface irregularities. For example, the mat layer 450 may be formed by forming a plurality of irregularities on the surface for forming the mat layer using a molding process, and then replicating the irregularities using a UV resin. According to one embodiment, the mat layer 450 may be formed in an irregular shape, at least a portion of which has a curved surface.

[0061] According to one embodiment, the coating layer 460 can be applied under the second base film 442. The coating layer 460 can protect a part of the light control film 400 (e.g., the second base film 442) from external impact. The coating layer 460 may be referred to as a hard coating layer.

[0062] FIG. 4 is a diagram showing the cut-off viewing angle versus the refractive index of the light-shielding pattern layer and the adhesive layer according to one embodiment of the present disclosure.

[0063] 4, light control film 400 may include a louver film 410, a reflective polarizing film 420, and an adhesive layer 430. The configurations of light control film 400, louver film 410, reflective polarizing film 420, and adhesive layer 430 in FIG. 4 may be the same as all or part of the configurations of light control film 400, louver film 410, reflective polarizing film 420, and first adhesive layer 431 in FIG. 2 and / or FIG. 3. For example, louver film 410 may include a first side surface 411a inclined at a first angle X1 with respect to reflective polarizing film 420 and / or adhesive layer 430, a second side surface 411b substantially perpendicular to reflective polarizing film 420 and / or adhesive layer 430, a lower surface 411c disposed on adhesive layer 430, and an upper surface 411d opposite to lower surface 411c.

[0064] According to one embodiment, the louver film 410 can transmit light that has passed through the reflective polarizing film 420 and the adhesive layer 430. The adhesive layer 430 can be disposed below the louver film 410. The reflective polarizing film 420 can be disposed below the adhesive layer 430.

[0065] According to an embodiment, the second refractive index of the light-absorbing pattern 411, the first refractive index of the light-transmitting portion 412, the third refractive index of the reflective polarizing film 420, and the fourth refractive index of the adhesive layer 430 may be different from each other. Because the refractive indexes of the light-transmitting portion 412, the reflective polarizing film 420, and the adhesive layer 430 are different from each other, the refraction angle of light may be changed depending on the thickness of the reflective polarizing film 420 and / or the thickness of the adhesive layer 430.

[0066] According to one embodiment, the refraction angle of light passing through the louver film 410 can be changed based on the thickness of the reflective polarizing film 420. As the thickness of the reflective polarizing film 420 increases, the path of light passing through the reflective polarizing film 420 increases, and the refraction angle of light passing through the light-transmitting portion 412 of the louver film 410 may be changed. For example, light passing through the light-transmitting portion 412 may be reflected at a third angle X3 from the second side surface 411b of the light-absorbing pattern 411. The third angle X3 may refer to the angle at which the screen output from the display device (e.g., the display device 1 of FIG. 1) is tilted or moved. As the refraction angle of light increases, the cut-off viewing angle and the brightness at the cut-off viewing angle may increase.

[0067] According to one embodiment, the refraction angle of light passing through the louver film 410 can be changed based on the thickness of the adhesive layer 430. For example, as the thickness of the adhesive layer 430 increases, the cutoff viewing angle can be increased. As the thickness of the adhesive layer 430 increases, the path of light passing through the adhesive layer 430 increases, which can change the refraction angle of light passing through the light-transmitting portion 412 of the louver film 410. As the refraction angle of light increases, the cutoff viewing angle brightness can increase along with an increase in the cutoff viewing angle. According to one embodiment, the adhesive layer 430 is located between the louver film 410 and the reflective polarizing film 420 and can support the multiple light-absorbing patterns 411 of the louver film 410.

[0068] FIG. 5 is a diagram comparing the properties of a light control film including a louver film and a reflective polarizing film according to one embodiment of the present disclosure with those of an existing light control film.

[0069] As a prior art example, the first comparative example A shows the optical characteristics of a display device that does not include a light control film. The second comparative example B shows the optical characteristics of a display device that includes a louver film but does not include a light control film. The brightness of the second comparative example B is 65.1% of that of the first comparative example A, confirming that it is difficult to use.

[0070] First Example C and Second Example D illustrate the optical characteristics of a display device including a light control film 400 of the present disclosure. First Example C and Second Example D may include the same louver film 410 but different values ​​of reflective polarizing film 420. For example, the thickness and / or refractive index of the reflective polarizing film 420 in First Example C may be different from that of the reflective polarizing film in Second Example D. Referring to First Example C and Second Example D, the reflective polarizing film (e.g., reflective polarizing film 420 in FIG. 2) can increase the viewing angle of the light control film 400 and enhance brightness.

[0071] Referring to the first Example C according to the present disclosure, the brightness may be 90.6% of that of the first Comparative Example A. The viewing angle at full width at half maximum (FWHM) may be about 47 degrees / 105 degrees. The peak value may be 1. The transmittance at a cutoff viewing angle of +45 degrees may be about 1.4%. The transmittance at a cutoff viewing angle of -45 degrees may be about 1.3%. The values ​​measured by the EU Zone standard may be about 73% and 40.2%. It can be seen that the brightness and the values ​​measured by the EU Zone standard of the first Example C are higher than those of the second Comparative Example B, which does not have a reflective polarizing film.

[0072] Referring to the second Example D according to the present disclosure, the brightness may be 91.2% of that of the first Comparative Example A. The peak value may be 2. The full width at half maximum (FWHM) viewing angle may be about 48 degrees / 105 degrees. The transmittance for a cutoff viewing angle based on +45 degrees may be about 1.4%. The transmittance for a cutoff viewing angle based on -45 degrees may be about 1.4%. The values ​​confirmed by the EU zone standard may be about 74% and 39.6%. It can be seen that the brightness and the values ​​confirmed by the EU zone standard of the second Example D are higher than those of the second Comparative Example B, which does not have a reflective polarizing film.

[0073] According to various embodiments of the present disclosure, a light control film may include a louver film including a plurality of light-absorbing patterns arranged side by side and a light-transmitting portion surrounding at least a portion of the plurality of light-absorbing patterns; a reflective polarizing film for polarization recycling configured to adjust the angle of light transmitted to the louver film; and a first adhesive layer disposed between the louver film and the reflective polarizing film. The difference between the first refractive index of the light-transmitting portion and the second refractive index of the plurality of light-absorbing patterns may be 0.05 or greater. The plurality of light-absorbing patterns may include first and second side surfaces formed asymmetrically with respect to each other. The difference between the refractive index of the transmissive layer and the refractive index of the light-absorbing patterns can increase the total reflection efficiency of the louver film. The asymmetric formation of the first and second side surfaces with respect to each other can improve the total reflection efficiency of the louver film.

[0074] According to one embodiment, the first side may be inclined at a first angle relative to the reflective polarizing film, and the second side may be substantially perpendicular to the reflective polarizing film.

[0075] According to one embodiment, the first angle may be between 3.5 degrees and 5 degrees.

[0076] According to one embodiment, the reflective polarizing film may be configured to transmit light within a specified range of angles and to reflect light beyond the specified angles.

[0077] According to one embodiment, the plurality of light-absorbing patterns may be arranged along a first direction, and the reflective polarizing film may include a transmission axis formed along the first direction.

[0078] According to one embodiment, the light control film may further include a first base film disposed on the louver film and a matte layer including a plurality of protrusions disposed on the first base film.

[0079] According to one embodiment, the plurality of protrusions may be formed in an irregular shape, at least a portion of which has a curved surface.

[0080] According to one embodiment, the plurality of light-absorbing patterns may include a lower surface facing the first adhesive layer and an upper surface opposite to the lower surface. The upper surface may be spaced apart from the first base film.

[0081] According to one embodiment, the light control film may further include a second base film located below the second adhesive layer, and a second adhesive layer located between the reflective polarizing film and the second base film.

[0082] According to one embodiment, the light control film may further include a coating layer located below the second base film.

[0083] According to one embodiment, the third refractive index of the reflective polarizing film may be different from the fourth refractive index of the first adhesive layer.

[0084] According to one embodiment, the first adhesive layer may be bonded to the lower surfaces of the plurality of light-absorbing patterns and the rear surface of the transmissive layer.

[0085] According to an embodiment, the backlight unit may include a light source, the light control film, and a light guide plate for transmitting light incident from the light source to the light control film.

[0086] According to an embodiment, a display device may include a liquid crystal panel and the backlight unit located below the liquid crystal panel.

[0087] The light control films of the various embodiments of the present disclosure described above are not limited to the above-described embodiments and drawings, and it will be apparent to those skilled in the art to which the present invention pertains that various substitutions, modifications and alterations are possible within the technical scope of the present disclosure. [Explanation of symbols]

[0088] 1: Display device 100: Backlight unit 400: Light control film 410: Louver film 411: Absorption pattern 412: Translucent part 420: Reflective polarizing film 430: Adhesive layer 440: Base film 450: Matte layer 460: Coating layer

Claims

1. a louver film including a plurality of light-absorbing patterns arranged side by side and a light-transmitting portion surrounding at least a portion of the plurality of light-absorbing patterns; A reflective polarizing film that transmits some of the light emitted from a light source and reflects other parts of the light; and a first adhesive layer disposed between the louver film and the reflective polarizing film; a difference between a first refractive index of the light-transmitting portion and a second refractive index of the plurality of light-absorbing patterns is 0.05 or more; the plurality of light-absorbing patterns include a first side surface and a second side surface that are asymmetrically formed with respect to each other; one surface of the first adhesive layer is in close contact with the reflective polarizing film, and the other surface is in close contact with the louver film; the portion of the light that has passed through the reflective polarizing film is refracted at an interface between the reflective polarizing film and the first adhesive layer, and is made to enter the louver film; A light control film, wherein the third refractive index of the reflective polarizing film is greater than the fourth refractive index of the first adhesive layer.

2. the first side is inclined at a first angle relative to a normal to the plane of the reflective polarizing film; The light control film of claim 1 , wherein the second side is perpendicular to the plane of the reflective polarizing film.

3. The light control film of claim 2 , wherein the first angle is between 3.5 degrees and 5 degrees.

4. 10. The light control film of claim 1, wherein the reflective polarizing film is configured to transmit light within a specified range of angles and to reflect light beyond the specified angles.

5. the plurality of light-absorbing patterns are arranged along a first direction; The light control film of claim 1 , wherein the reflective polarizing film includes a transmission axis formed along the first direction.

6. a first base film disposed on the louver film; and The light control film of claim 1 further comprising a matte layer including a plurality of protrusions disposed on the first base film.

7. The light control film according to claim 6 , wherein the plurality of protrusions are formed in an irregular shape, at least a portion of which has a curved surface.

8. the plurality of light-absorbing patterns include a lower surface facing the first adhesive layer and an upper surface opposite to the lower surface; The light control film of claim 6 , wherein the top surface is spaced apart from the first base film.

9. a second base film positioned below the reflective polarizing film; and The light control film of claim 1 further comprising a second adhesive layer positioned between the reflective polarizing film and the second base film.

10. The light control film of claim 9 further comprising a coating layer underlying the second base film.

11. The light control film according to claim 1 , wherein the first adhesive layer is bonded to the lower surfaces of the plurality of light-absorbing patterns and the rear surface of the light-transmitting portion.

12. light source, The light control film of claim 1 , and a backlight unit including a light guide plate for transmitting light incident from the light source to the light control film;

13. LCD panels, and A display device comprising the backlight unit according to claim 12 located below the liquid crystal panel.

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