Patent ID: 12222602

DETAILED DESCRIPTION

Various embodiments and terms used in the specification are not intended to limit the technical features described in the specification to specific embodiments, but it should be understood to include various modifications, equivalents, or substitutions of the embodiments. In connection with the description of the drawings, similar reference numerals may be used for similar or related components. The singular form of the noun corresponding to the item may include one or more of the elements unless the relevant context clearly dictates otherwise.

According to various embodiments, each component (e.g., film or sheet) of the above-described components may include a single or plural entity, and some of the plurality of entities may be separately placed in other components. According to various embodiments, one or more of the components or operations described above may be omitted, or one or more other components or operations may be added. Multiple components (e.g., films or sheets) may be alternatively or additionally integrated into a single component. In this case, the integrated component may perform one or more functions of each component of the plurality of components in the same or similar manner as those performed by the corresponding component of the plurality of components prior to the integration.

Embodiments will be described with reference to the associating drawings. In describing the present embodiment, the same names and the same reference numerals are used for the same components, and an additional description thereof will be omitted. In addition, in describing the embodiment of the present invention, the same names and reference numerals are used for components having the same functions, and it is substantially not completely the same as in the prior art.

According to various embodiments, terms such as “comprise” or “have” are intended to designate the presence of a feature, number, step, operation, component, part, or combination described in the specification. It should be understood, however, that the above does not preclude the possibility of addition or existence of one or more of other features, or numbers, steps, operations, components, parts, or combinations.

FIG.1is a schematic showing a conventional liquid crystal display (LCD) device including a diffusion sheet. Referring toFIG.1, a liquid crystal display (LCD) device1may include a backlight unit10and a liquid crystal panel20. According to various examples, the backlight unit10may be disposed toward the rear direction (a direction facing the −Z-direction) of the liquid crystal panel20to emit light to the liquid crystal panel20. The backlight unit10may include a substrate11including a light source11a, a color conversion sheet13, diffusion sheets14,17, and prism sheets15,16. The backlight unit10may further include a reflective polarizing sheet although it not shown inFIG.1.

According to various embodiments, the light source11ais configured to emit light to the back of the liquid crystal panel20and may be disposed on one side of the substrate11. The light source11amay be a light emitting diode (referred to as LED). The light source11amay include, for example, a plurality of LED chips11athat emit light. Depending on the size of the LED chip, LEDs are classified into a large LED (chip size: 1,000 μm or more), a middle LED (chip size: 300-500 μm), and a small LED (chip size: 200 μm-300 μm), a mini LED (chip size: 100-200 μm), and a micro LED (chip size: 100 μm or less). Here, the LED may include material such as InGaN and GaN. Light emitted from the light source11amay be emitted toward the liquid crystal panel20(+Z-direction). Light emitted from the light source11amay pass through the color conversion sheet13and enter the diffusion sheet14.

According to various embodiments, a reflective sheet12may be formed on the surface of the substrate11. The reflective sheet12may include material such as BaSO4, TiO2, CaCO3, SiO2, Ca3(SO4)2or may include material such as Ag. It may be deposited or coated between the light sources11aon a substrate11. The reflective sheet12may serve to reflect light which was reflected toward the substrate11by interfacial reflection while the emitted light from the light source11apassed through the color conversion sheet13, diffusion sheets14,17, and prism sheets15,16back in the direction where the light was emitted. Through this, loss of light can be minimized. In other words, the reflective sheet12can perform light recycling.

According to various embodiments, the color conversion sheet13can convert the color of light emitted from the light source11a. For example, the light from a mini LED or a micro LED may be blue light (450 nm). In this case, the blue light needs to be converted to white light. The color conversion sheet13can transmit the blue light emitted from the light source11aand simultaneously convert the blue light into the white light.

According to various embodiments, the diffusion sheets14,17may uniformly disperse light incident from the color conversion sheet13. The diffusion sheets14,17which curable resin solution including light diffuser beads (e.g., at least one or more selected from urethane acrylate, epoxy acrylate, ester acrylate, ester acrylate, and radical generating monomer added as a single or a mixed) was deposited can cause light diffusion by the light diffuser beads. Additionally, the diffusion sheets14,17may be formed with uniform size or non-uniform size shape (for example, spherical shape) of protrusion patterns (or protrusions) to promote the light diffusion.

According to various embodiments, the diffusion sheets14,17may include a lower diffusion sheet14and an upper diffusion sheet17. The lower diffusion sheet14may be disposed between the color conversion sheet13and the prism sheet15and the upper diffusion sheet17may be disposed between the prism sheet16and the liquid crystal panel20. If the back light unit10further includes a reflective polarizing sheet, the upper diffusion sheet17may be disposed between the prism sheet16and the reflective polarizing sheet.

According to various embodiments, the prism sheets15,16can condense incident light using an optical pattern formed on the surface, and then, emit it to the liquid crystal panel20. The prism sheets15,16may include a light-transmitting base film and a prism pattern layer formed on an upper surface (a surface facing the +Z-direction) of the base film. The prism pattern layer may be formed as an optical pattern layer in the form of a triangular array with an inclined surface at a specified angle (for example, an inclined surface of 45°) to improve brightness in the planar direction. The prism patterns of the prism pattern layer may be in the shape of a triangular pillar and may be arranged so that one side of the triangular pillar faces the base film.

According to one embodiment, the prism sheets15,16may include a first prism sheet15and a second prism sheet16to form a composite prism sheet structure. Here, the second prism sheet16may be disposed to overlap the upper surface of the first prism sheet15. In the first prism sheet15, a plurality of first prism patterns may be arranged side by side with each other. Each first prism pattern may have a structure extending in one direction. For example, the vertex line15aof each of the first prism patterns may be formed to extend to X-direction. Similarly, in the second prism sheet16, a plurality of second prism patterns may also be arranged side by side with each other. Each second prism pattern may have a structure extending in another direction. For example, the vertex line16aof each of the second prism patterns may be formed to extend in a direction perpendicular to the X-axis and Z-axis (referred to as ‘Y-direction’). Here, the extension direction of the first prism patterns and the extension direction of the second prism patterns are shown as directing to the X-direction and the Y-direction for the convenience of explanation. However, it is not limited to the illustrated embodiment and may be oriented in a direction other than the X-direction or the Y-direction.

According to various embodiments, a reflective polarizing sheet (not shown) is provided on the prism sheets15,16and the upper diffusion sheet17. The reflective polarizing sheet may serve to transmit some polarized light and to reflect other polarized light downward as to the light condensed from the prism sheets15,16and diffused by the upper diffusion sheet17.

According to various embodiments, the liquid crystal panel20may refract light emitted from the light source11ato a predetermined pattern according to an electrical signal. The refracted light may pass through a color filter and a polarizing filter disposed on the front of the liquid crystal panel20to form a screen image.

FIG.2is a schematic illustrating a liquid crystal display (LCD) device including a backlight unit provided with a shielding sheet where a plurality of films is laminated according to various embodiments of the present invention. Referring toFIG.2, a liquid crystal display (LCD) device1according to an embodiment of the present invention includes a backlight unit10and a liquid crystal panel20. The backlight unit10may include a substrate11including a light source11a, a color conversion sheet13, an optical film100, prism sheets15,16, and a diffusion sheet17. According to one embodiment, a reflective sheet12may be formed on one side of the light source11a.

According to one embodiment, at least one of these components (e.g., the diffusion sheet17) may be omitted from or one or more other components (e.g., a reflective polarizing sheet (not shown)) may be added to the backlight unit10. Here, description of parts overlapping withFIG.1will be omitted.

The liquid crystal display (LCD) device1of the present invention may be characterized by providing at least one optical film formed in a laminate structure. Here, at least one optical film100may replace the lower diffusion sheet14or may be additionally provided. Here, explanation as to the drawings of the present invention may be given for at least one optical film provided on one side as an example for replacing the lower diffusion sheet14.

In the present specification, an ‘optical film’ may refer to a structure where a light-transmitting base film (referred to as ‘base portion’) provided with a first pattern on one side and two diffusion sheets further including a second pattern on the other side of the base portion are laminated together. Additionally, at least one optical film may include a structure where two optical films are stacked each other. However, it is not limited to this, and in some cases, it may include three or more optical films. Although the drawing ofFIG.2is somewhat exaggerated for the convenience of explanation, it shows that two very thin sheets110,120having different thicknesses are laminated to form the first optical film100.

In the present specification, ‘lamination’ may mean that at least one of two different sheets is provided with an adhesive and adhered together. The laminated optical film can provide a backlight unit that is thinner and has excellent shielding performance compared to an embodiment where the optical film is simply stacked rather than laminated.

According to various embodiments of the present invention, the first optical film100may be configured to have the first sheet110and the second sheet120having a thickness of the base portion of approximately 100 μm to be laminated together in a case where two different diffusion sheets110,120form one optical film. The first optical film100in the present invention may be provided on the color conversion sheet13for replacing or being added to the lower diffusion sheet14.

The optical film100(referred to as ‘laminated optical film’) according to various embodiments of the present invention may be provided with high rigidity and excellent shielding performance while it is thinner by a several μm or more compared to an embodiment where two or three sheets with a thickness of approximately 100 μm or approximately 160 μm, for example, are simply stacked (referred to as ‘unlaminated optical film’). For example, according to a simulation result conducted by an inventor, the laminated optical film with a thickness of approximately 327 μm may provide the brightness value corresponding to or excellent over the brightness value of the unlaminated optical film with a thickness of approximately 335 μm where the two different diffusion sheets described above are not laminated while the laminated optical film has a thinner thickness.

FIG.3is a side view showing an optical film where a plurality of sheets is laminated according to various embodiments of the present invention.FIG.4is a perspective view showing an optical film where a plurality of sheets is laminated according to various embodiments of the present invention.

In the present specification, a backlight unit (e.g., backlight unit10ofFIGS.1and2) may include a first optical film100. The first optical film100may include a first sheet110and a second sheet120laminated with the first sheet110.

According to one embodiment of the present invention, the first sheet110of the first optical film100may include a first base portion112and a second base portion122. The first optical film100may include a first pattern layer111including a first pattern disposed on one surface of the first base portion112and a second pattern layer113including a second pattern different from the first pattern disposed on the other surface of the first base portion112. The second sheet120of the first optical film100may include a third pattern layer121including a third pattern on one surface of the second base portion122and a fourth pattern layer123including a fourth pattern different from the third pattern disposed on the other surface of the second base portion122.

According to one embodiment, the first base portion112and the second base portion122may have thicknesses corresponding to each other. For example, the first base portion112and the second base portion122may have a thickness of approximately 100 μm. If the base portion is thin, it may be damaged by heat generated from the light source11athereby causing the sheet to be unevenly swelled (sheet warping phenomenon). Therefore, according to another embodiment, the thickness of the second base portion122close to the light source11amay be formed to be thicker than the thickness of the first base portion112to prevent the sheet from being unevenly swelled thereby improving the reliability of a product.

According to one embodiment, the brightness performance of the first optical film100can be improved based on the refractive index of each layer which included in the first sheet110and the second sheet120of the first optical film100. For the first optical film100, when the refractive index of the light input layer and the refractive index of the light output layer are formed to be equal, as the brightness performance can be improved. Thus, the refractive index of the fourth pattern layer123which is the light input layer may be the same as the refractive index of the first pattern layer111which is the light output layer. For example, the refractive index of the first pattern layer111and the fourth pattern layer123may be approximately 1.50 to 1.70, respectively. For another example, the refractive index of the first pattern layer111and the refractive index of the fourth pattern layer123may each be approximately 1.60. Additionally, the refractive index of the second pattern layer113may be approximately 1.50 to 1.70 and the refractive index of the third pattern layer121may be approximately 1.45 to 1.55. For example, the refractive index of the second pattern layer113may be approximately 1.60 and the third pattern layer121may be coated with adhesive material and may have a refractive index of approximately 1.51.

FIG.5is a schematic and images illustrating a plurality of sheets included in an optical film according to various embodiments of the present invention. In the present specification, a backlight unit (e.g., backlight unit10ofFIGS.1and2) may include a first optical film100. The first optical film100may include a first sheet110and a second sheet120laminated with the first sheet110. The configuration of the first sheet110and the second sheet120ofFIG.5may be partially or entirely the same as the configuration of the first sheet110and the second sheet120ofFIGS.3and4.

Practically, the first sheet110and the second sheet120are laminated together to form one film. For the convenience of explanation, the first sheet110and the second sheet120are separately shown inFIG.5.

According to various embodiments, the first sheet110may include a first base portion112, a first pattern layer111including a first pattern disposed on one surface of the first base portion112, and a second pattern layer113including a second pattern disposed on the other surface of the base portion112. The first pattern layer111may be disposed on a surface of the first base portion112facing the +Z-direction and the second pattern layer113may be disposed on a surface of the first base portion112facing the −Z-direction.

According to one embodiment, the first base portion112may be configured to support the first pattern layer111and/or the second pattern layer113. For example, the first base portion112is made of transparent material capable of transmitting light. For example, it may include material such as a polycarbonate series, a polysulfone series, a polyacrylate series, a polystyrene series, a poly vinyl chloride series, a polyvinyl alcohol series, a polynorbornene series, and a polyester series. For a specific example, the base portion112may be made of at least one of polyethylene terephthalate or polyethylene naphthalate.

According to various embodiments, the first pattern layer111may include a plurality of prism patterns having a parallel pattern direction toward a first direction (e.g., A-direction). A cross-section of each of the plurality of prism patterns may be triangular. Each of the plurality of prism patterns may be designed to have a size that gradually decreases toward the +Z-direction.

According to various embodiments, the second pattern layer113may include a plurality of pyramid patterns having a plurality of rows in a second direction (e.g., B-direction) and a plurality of columns in a third direction perpendicular to the second direction (e.g., B′-direction). A cross-section of each of the plurality of pyramid patterns may have a triangular or trapezoidal shape. The plurality of pyramid patterns may be designed as intaglio patterns when they are viewed from below the second pattern layer113(viewed toward the +Z-direction). According to one embodiment, the second direction (e.g., B-direction) may face a different direction from the first direction (e.g., A-direction). According to one embodiment, the angle ϕ formed between the second direction (e.g., B-direction) and the first direction (e.g., A-direction) may be configured to have approximately 45° (e.g., 40° to 50°). The brightness performance may be improved by setting the second direction (e.g., B-direction) to form an angle of approximately 45° with the first direction (e.g., A-direction) and setting a direction of the fourth pattern layer123disclosed below to be the same as the direction of the second pattern layer113. Each of the plurality of pyramid patterns is formed in an intaglio shape and may be designed to have a size that gradually increases toward the −Z-direction.

According to one embodiment, the thickness of the first base portion112may be approximately 100 μm. However, the thickness of the first base film112is not limited to the above example and may be designed in various ways to be suitable for supporting the first pattern layer111and the second pattern layer113.

The first sheet110according to the present invention may be provided to increase the effect of reducing light interference and color non-uniformity along with the light diffusion effect by disposing the pattern layers (a first pattern layer111and a second pattern layer113) on one surface and the other surface, in other words, on both surfaces, of the first base portion112. According to one embodiment, micro-patterning of the first pattern layer111and the second pattern layer113may be implemented by depositing UV (ultraviolet) curable resin solution to one surface (or the other side) of the base portion112and irradiating light.

According to various embodiments, as to the light diffusion effect, light incident to the second pattern layer113may be diffused through a plurality of pyramid patterns formed on the second pattern layer113. The second pattern layer113may transmit light to the direction (+Z-direction) of light emitted from the light source11a. In this process, loss of light can be minimized by refracted light refracted on the interface of the pyramid pattern and reflected light caused by interface reflection. In addition, reduction in brightness can be minimized. The pyramid patterns formed on the second pattern layer113may include a plurality of pyramids (e.g., M×N pyramids). A pyramid pattern with M rows and N columns may be formed to at least partially overlap the light source11aformed on the substrate11.

According to various embodiments, the first sheet110may include the first pattern layer111where the prism pattern with a predetermined height (or thickness) (a) and a pitch distance (b) is formed. In addition, the second pattern layer113where the pyramid pattern with a predetermined height (or thickness) (c) and a pitch distance (d) is formed.

According to one embodiment, the backlight unit may improve brightness by controlling the vertex angle of the first pattern layer111and the second pattern layer113of the first sheet110. In general, for the lower pattern layer where the pyramid pattern is formed, light may be refracted in a condensed way when the vertex angle is approximately 130° and light may be refracted in a dispersed way when the vertex angle is approximately 90°. In addition, for the upper pattern layer where the prism pattern is formed, retroreflection may be active as light recycling occurs more when the vertex angle is approximately 90°. According to one embodiment, the vertex angle of the pyramid pattern of the second pattern layer113may be set to be approximately 90° and the vertex angle of the prism pattern of the first pattern layer111may be set to be approximately 90°. As for an optical path provided to the first sheet110, light may be incident to the second pattern layer113and then be emitted through the first base portion112and the first pattern layer111. Accordingly, the incident light provided to the first sheet110may provide condense light refracted in a dispersed way by the pyramid pattern of the second pattern layer113, undergo active retroreflection caused by recycling, and then provide emitted light in a way to be condensed at the center by the prism pattern of the first pattern layer113.

According to one embodiment, the height (a) and the pitch distance (b) of the prism pattern may be defined based on the first vertex angle (θ1) for the first pattern layer111. Here, the first vertex angle (θ1) may be defined as the angle between two opposing surfaces among the three surfaces forming a prism pattern with a triangular cross-section. For example, the first vertex angle (θ1) may be defined within 70° to 120°. And the height (a) and the pitch distance (b) of the prism pattern with a triangular cross-section may be defined according to a ratio based on the first vertex angle (θ1). For example, when the first vertex angle (θ1) for the first pattern layer111is less than 90° (e.g., 70° to 90°), the ratio of the height (a) to the pitch distance (b) for the prism pattern can be defined as approximately 1:1.4 to 1:2. For example, the height (a) of the prism pattern may be approximately 20 μm to approximately 40 μm and the pitch distance (b) of the prism pattern may be approximately 28 μm to 80 μm. For another example, the height (a) of the prism pattern may be approximately 20 μm to approximately 40 μm and the pitch distance (b) of the prism pattern may be approximately 40 μm to 60 μm. More specifically, it may be desirable for the height (a) of the prism pattern to be approximately 30 μm and the pitch distance (b) of the prism pattern to be approximately 50 μm. The first sheet110with improved brightness can be provided by the ratio of the height (a) and pitch distance (b) of the prism pattern.

According to another embodiment, the height (c) and pitch distance (d) of the pyramid pattern may be defined based on the second vertex angle (θ2) for the second pattern layer113. Here, the second vertex angle (θ2) may be defined as the angle between two opposing surfaces among the four surfaces forming a pyramid pattern with a trapezoidal cross-section. For example, the second vertex angle (θ2) may be defined within a range of 90° to 150°. Within a specified range, as the vertex angle of the pyramid pattern is increased, the diffusivity of light incident on the first sheet110may further be decreased. If the vertex angle is decreased, the diffusivity of light may be increased, and brightness loss may be increased. And the height (c) and pitch distance (d) of the pyramid pattern with a trapezoidal cross-section may be defined according to a ratio based on the second vertex angle (θ2). For example, when the first vertex angle in the first pattern layer111is fixed at 90° and the second vertex angle is 90°, the ratio of the height (c) to the pitch distance (d) of the pyramid pattern can be defined as 1:2. For example, the height (c) of the pyramid pattern may be about 40 μm to about 60 μm, and the pitch distance (d) of the pyramid pattern may be about 80 μm to 120 μm. More specifically, it may be desirable that the height (c) of the pyramid pattern is approximately 50 μm, and the pitch distance (d) of the pyramid pattern is approximately 100 μm. A plurality of pyramid patterns having such heights (c) and pitch distances (d) may be regularly arranged in the lower part of the shielding sheet110. The first sheet110with improved brightness can be provided by the ratio of the height (c) to pitch distance (d) of the pyramid pattern.

Because a plurality of pyramid patterns corresponds 1:1 with a light source (e.g., light source11ainFIG.2) formed on a substrate (e.g., substrate11inFIG.2) or is arranged in a way where the pyramid patterns at least partially overlap to the light source, a point light source emitted from the light source is diffused as the surface light source. In addition, because the light from the light source11ais separated (or diffused) by the diffusion action of the optical film100, hot spot visibility (HSV) due to the concentration of light can be reduced.

According to various embodiments, the second sheet120may include a second base portion122, a third pattern layer121including a third pattern disposed on one surface of the second base portion122, and a fourth pattern layer123including a fourth pattern disposed on the other surface of the base portion122. The third pattern layer121may be disposed on the surface of the second base portion122facing the +Z-direction and a fourth pattern layer123may be disposed on the surface of the second base portion122facing the −Z-direction.

According to one embodiment, the second base portion122may be configured to support the third pattern layer121and/or the fourth pattern layer123. The thickness of the second base portion122may be approximately 100 μm. However, the thickness of the second base film122is not limited to the above example and may be designed in various ways to be suitable for supporting the third pattern layer121and the fourth pattern layer123. The second base portion122is made of transparent material capable of transmitting light. For example, it may include material such as a polycarbonate series, a polysulfone series, a polyacrylate series, a polystyrene series, a poly vinyl chloride series, a polyvinyl alcohol series, a polynorbornene series, and a polyester series. For a specific example, the base portion112may be made of at least one of polyethylene terephthalate or polyethylene naphthalate.

According to various embodiments, the third pattern layer121may be formed as a matte pattern. For example, the third pattern layer121may have a plurality of protrusion portions (e.g., protrusions) arranged irregularly. Each of the plurality of protrusion portions may be randomly formed and may protrude toward the +Z-direction.

According to one embodiment, the plurality of protrusion portions of the third pattern layer121may not have a direction unlike the first pattern layer111, the second pattern layer113, and the fourth pattern layer123. At least some of the plurality of protrusion portions of the third pattern layer121may have a curved shape. An adhesive layer is deposited to the upper surface of the plurality of protrusion portions of the third pattern layer121. And then, as it is adhered to the second pattern layer113of the first sheet110, the second sheet120and the first sheet110can be laminated to provide as a composite structure.

According to various embodiments, the fourth pattern layer123may include a plurality of pyramid patterns having rows in a second direction (e.g., B-direction) and having columns in a third direction perpendicular to the second direction (e.g., B′-direction). The fourth pattern layer123may be manufactured into a shape corresponding to the second pattern layer113.

According to one embodiment, a cross-section of each of the plurality of pyramid patterns of the fourth pattern layer123may have a triangular or trapezoidal shape. The plurality of pyramid patterns may be designed as intaglio patterns when viewed from below the fourth pattern layer123(viewed toward the +Z-direction). According to one embodiment, the second direction (e.g., B-direction) may face a different direction from the first direction (e.g., A-direction). According to one embodiment, the angle ϕ formed between the second direction (e.g., B-direction) and the first direction (e.g., A-direction) may be formed to have an angle of approximately 45° (e.g., 40° to 50°). The brightness performance can be improved as the second direction (e.g., B-direction) is configured to have an angle of approximately 45° with the first direction (e.g., A-direction) and the directions of the second pattern layer113and the fourth pattern layer123disclosed above is configured to be the same. Each of the plurality of pyramid patterns may be formed in an intaglio shape and may be designed to have a size that gradually increases toward the −Z-direction.

According to one embodiment, the height and the pitch distance of the pyramid pattern of the fourth pattern layer123may be applied to the configuration of the second pattern layer113. For example, the height and the pitch distance of the pyramid pattern of the fourth pattern layer123may be defined based on the third vertex angle (θ3).

FIG.6Ais a table showing brightness, beam width, and brightness values with respect to the vertex angle of each prism according to various embodiments of the present invention.FIG.6Bis a graph showing beam width and brightness values with respect to the vertex angle of each prism according to various embodiments of the present invention.

Referring toFIGS.6A and6B, in a case where the second vertex angle (θ2) of the pyramid pattern of the second pattern layer (e.g., the second pattern layer113inFIG.5) is fixed while the first vertex angle (θ1) of the prism pattern of the first pattern layer (e.g., the first pattern layer111inFIG.5) is varied, the brightness, beam width, and the brightness values can be confirmed. In the drawings according to various embodiments of the present invention includingFIGS.6A and6B, the beam width may mean the area where the light passing through the shielding-sheet is dispersed based on the light source (LED). If the beam width is larger, hot spot visibility (HSV) due to the concentration of light is improved because of the light separation (or light diffusion). As a result, optical characteristics are shown to be excellent. In the drawings according to various embodiments of the present invention includingFIGS.6A and6B, the brightness is a measurement of brightness of light radiated from a light source and indicates how bright the light source appears to an observer when viewed from a specific direction. And the unit is nit. As the nit value is increased, the brightness is increased, and optical characteristics are improved.

According to various embodiments, the beam width and the brightness values were measured when the second vertex angle (θ2) of the pyramid pattern of the second pattern layer113was fixed at approximately 130° while the first vertex angle (θ1) of the prism pattern of the first pattern layer111was varied from approximately 70° to 120°.

Referring toFIGS.6A and6Btogether, when the first vertex angle (θ1) of the prism pattern is 70°, the beam width is 2.77 mm, when it is 80°, the beam width is 3.85 mm, when it is 90°, the beam width is 3.92 mm, when it is 100°, the beam width is 2.83 mm, when it is 110°, the beam width is 2.41 mm, and when it is 120°, the beam width is 2.71 mm. It can be confirmed that the beam width reaches its maximum value at 90°.

Meanwhile, when the first vertex angle (θ1) of the prism pattern is 70°, the brightness value is 30,773.0, when it is 80°, the brightness value is 21,179.7, when it is 90°, the brightness value is 8,219.3, when it is 100°, the brightness value is 9,397.3, when it is 110°, the brightness value is 20,204.3, and when it is 120°, the brightness value is 27,346.4. The brightness value reaches its minimum value when the first vertex angle (θ1) of the prism pattern is approximately 90° and it can be confirmed that the brightness performance is improved as the vertex angle becomes smaller or larger than 90°.

Referring toFIGS.6A and6B, it can be confirmed that the optical film has excellent optical performance from a shielding perspective when the vertex angle of the pyramid pattern is fixed at 130° and the vertex angle of the prism pattern is 80° to 90°. According to various embodiments of the present invention, the vertex angle of a desirable prism pattern can be set with respect to the intersection of a line for the beam width and a line for the brightness value.

FIG.7Ais a table showing brightness, beam width, and brightness values with respect to the vertex angle of each prism according to various embodiments of the present invention.FIG.7Bis a graph showing beam width and brightness values with respect to the pitch distance of each prism according to various embodiments of the present invention.

Referring toFIGS.7A and7B, in a case where the second vertex angle (θ2) of the pyramid pattern of the second pattern layer (e.g., the second pattern layer113inFIG.5) is fixed while the first vertex angle (θ1) of the prism pattern of the first pattern layer (e.g., the first pattern layer111inFIG.5) is fixed, the brightness, beam width, and the brightness values can be confirmed.

According to various embodiments, the beam width and the brightness values were measured when the second vertex angle (θ2) of the pyramid pattern of the second pattern layer113was fixed at approximately 130° and the first vertex angle (θ1) of the prism pattern of the first pattern layer111was fixed at approximately 90° while the pitch distance of the prism pattern was varied from 10 μm to 90 μm.

Referring toFIGS.7A and7Btogether, when the pitch distance of the prism pattern is 10 μm, the beam width is 4.19 mm, when the pitch distance is 30 μm, the beam width is 4.14 mm, when the pitch distance is 50 μm, the beam width is 3.92 mm, when the pitch distance is 70 μm, the beam width is 4.18 mm, and when the pitch distance is 90 μm, the beam width is 3.96 mm. It can be confirmed that the minimum beam width is when the pitch distance is 50 μm.

Meanwhile, it can be confirmed that when the pitch distance of the prism pattern is 10 μm, the brightness value is 10,772.7, when the pitch distance is 30 μm, the brightness value is 11,353.6, when the pitch distance is 50 μm, the brightness value is 8,219.3, and when the pitch distance is 70 μm, the brightness value is 10,078.7, and when the pitch distance is 90 μm, the brightness value is 10,565.2. The brightness value shows the minimum value when the pitch distance of the prism pattern is approximately 50 μm and it can be confirmed that the brightness performance improves as the pitch distance becomes smaller or larger than approximately 50 μm. It can be confirmed that the maximum brightness value is shown when the pitch distance of the prism pattern is 30 μm.

Referring toFIGS.7A and7B, it can be confirmed that the optical film has excellent optical performance from the perspective of shielding performance and the brightness value if the pitch distance of the prism pattern is smaller when the vertex angle of the pyramid pattern is fixed at 130° and the vertex angle of the prism pattern is fixed at 90°. According to various embodiments of the present invention, the pitch distance of a desirable prism pattern can be set with respect to the intersection of a line for the beam width and a line for the brightness value. Referring toFIG.7B, the prism pattern may be preferably formed to have a pitch distance of 10 μm to 30 μm according to various embodiments of the present invention.

FIG.8Ais a table showing brightness, beam width, and brightness values with respect to the vertex angle of each pyramid according to various embodiments of the present invention.FIG.8Bis a graph showing beam width and brightness values with respect to the vertex angle of each pyramid according to various embodiments of the present invention.

Referring toFIGS.8A and8B, in a case where the first vertex angle (θ1) of the prism pattern of the first pattern layer (e.g., the first pattern layer111inFIG.5) is fixed while the second vertex angle (θ2) of the pyramid pattern of the second pattern layer (e.g., the second pattern layer113inFIG.5) is varied, the brightness, beam width, and the brightness values can be confirmed.

According to various embodiments, the beam width and the brightness values were measured when the first vertex angle (θ1) of the prism pattern of the first pattern layer111was fixed at approximately 90° while the second vertex angle (θ2) of the pyramid pattern of the second pattern layer113was varied from approximately 90° to 130°.

Referring toFIGS.8A and8Btogether, when the second vertex angle (θ2) of the pyramid pattern is 90°, the beam width is 3.00 mm, when it is 100°, the beam width is 3.17 mm, when it is 110°, the beam width is 3.48 mm, when it is 120°, the beam width is 4.25 mm, when it is 130°, the beam width is 4.33 mm, when it is 140°, the beam width is 4.50 mm, and when it is 150°, the beam width is 3.75 mm. It can be confirmed that the beam width reaches its maximum value at 140°.

Meanwhile, when the second vertex angle (θ2) of the pyramid pattern is 90°, the brightness value is 43,472.7, when it is 100°, the brightness value is 24,430.2, when it is 110°, the brightness value is 18,246.4, and when it is 120°, the brightness value is 13,252.0, when it is 130°, the brightness value is 8,852.5, when it is 140°, the brightness value is 8,093.3, and when it is 150°, the brightness value is 7,858.4. The brightness value reaches its maximum value when the second vertex angle (θ2) of the pyramid pattern is approximately 90° and it can be confirmed that the brightness performance is deteriorated as the vertex angle is increased with respect to approximately 90°.

Referring toFIGS.8A and8B, it can be confirmed that the beam width and brightness values tend to be inversely proportional to each other in most ranges. For example, when the vertex angle of the prism pattern is fixed at 90° and the vertex angle of the pyramid pattern is 90° (e.g., approximately 85° to 95°), excellent optical performance is shown from the brightness perspective. When the vertex angle of the prism pattern is fixed at 90° and the vertex angle of the pyramid pattern is 140° (for example, approximately 130° to 145°), excellent optical performance can be shown from the beam width perspective. According to various embodiments of the present invention, the vertex angle of a desirable pyramid pattern can be set with respect to the intersection of a line for the beam width and a line for the brightness value. Accordingly, referring toFIG.8B, it can be designed to have the vertex angle of the pyramid pattern being at approximately 90° (e.g., 85° to 95°) while the vertex angle of the prism pattern is fixed at approximately 90° to ensure excellent brightness performance.

FIG.9Ais a table showing brightness, beam width, and brightness values with respect to the pitch distance of each pyramid according to various embodiments of the present invention.FIG.9Bis a graph showing beam width and brightness values with respect to the pitch distance of each pyramid according to various embodiments of the present invention. Referring toFIGS.8A and8B, in a case where the second vertex angle (θ2) of the pyramid pattern of the second pattern layer (e.g., the second pattern layer113inFIG.5) and the first vertex angle (θ1) of the prism pattern of the first pattern layer (e.g., the first pattern layer111inFIG.5) are fixed, the brightness, beam width, and the brightness values can be confirmed.

According to various embodiments, the beam width and the brightness values were measured when the second vertex angle (θ2) of the pyramid pattern of the second pattern layer113was fixed at approximately 130° and the first vertex angle (θ1) of the prism pattern of the first pattern layer111was fixed at approximately 90° while the pitch distance of the prism pattern was varied from 40 μm to 90 μm. Referring toFIGS.9A and9Btogether, when the pitch distance of the prism pattern is 40 μm, the beam width is 3.77 mm, when the pitch distance is 60 μm, the beam width is 3.60 mm, when the pitch distance is 80 μm, the beam width is 3.49 mm, and when the pitch distance is 100 μm, the beam width is 3.23 mm. It can be confirmed that the beam width performance may be deteriorated as the pitch distance of the pyramid pattern becomes wider.

Meanwhile, it can be confirmed when the pitch distance of the pyramid pattern is 40 μm, the brightness value is 10,282.0, when the pitch distance is 60 μm, the brightness value is 10,627.2, when the pitch distance is 80 μm, the brightness value is 13,909.8, and when the pitch distance is 100 μm, the brightness value is 14,405.2. It can be confirmed that the pitch distance reaches a maximum value around 100 μm as the pitch distance of the pyramid pattern is gradually increased.

Referring toFIGS.9A and9B, it can be confirmed that the beam width and brightness values tend to be inversely proportional to each other in most ranges. For example, with the vertex angle of the pyramid pattern being fixed at 130° and the vertex angle of the prism pattern being fixed at 90°, it can be confirmed that the optical film has excellent optical performance from the beam width perspective as the pitch distance of the pyramid pattern becomes smaller. With the vertex angle of the pyramid pattern being fixed at 130° and the vertex angle of the prism pattern being fixed at 90°, it can be confirmed that the optical film has excellent optical performance from the brightness perspective as the pitch distance of the pyramid pattern becomes larger (for example, the pitch distance is 80 μm to 100 μm). According to various embodiments of the present invention, the pitch distance of a desirable pyramid pattern can be set with respect to the intersection of a line for the beam width and a line for the brightness value. Referring toFIG.9B, the pyramid pattern can be designed to have a pitch distance of approximately 100 μm (e.g., 80 μm to 120 μm) to ensure excellent brightness performance.

The optical film of various embodiments of the present invention described above and the backlight unit including the optical film are not limited to the above-described embodiments and drawings. Moreover, various substitutions, modifications, and changes are possible for those skilled in the art within the technical scope of the present invention. The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description above.