Liquid crystal display device

Abstract

A liquid crystal display device is disclosed. The liquid crystal display device includes a liquid crystal panel, a viewer-side polarizing plate stacked on a light exit surface of the liquid crystal panel, and a first optical sheet and a second optical sheet stacked in sequence on a light entrance surface of the liquid crystal panel, wherein the viewer-side polarizing plate includes a polarizer and a contrast or viewing angle enhancement layer, the liquid crystal panel has a horizontal direction corresponding to a long side thereof and a vertical direction corresponding to a short side thereof, and the first optical sheet has a plurality of first optical patterns on a light exit surface thereof, a longitudinal direction of the first optical patterns having an angle in a range of -10° to +10° with respect to the vertical direction of the liquid crystal panel.

Description

[0001] Cross-reference of related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2022-0025062, filed on February 25, 2022, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to a liquid crystal display device. Background Technology

[0004] In the operation of a liquid crystal display (LCD), light emitted from the backlight unit is emitted through the liquid crystal panel. Therefore, the screen of an LCD has a good contrast ratio (CR) on its front side. However, the contrast ratio of the LCD screen on the sides is lower than that on the front side. Therefore, it is recommended to use a film with a predetermined pattern to improve contrast and viewing angle.

[0005] Liquid crystal displays (LCDs) operate not only in a "bright" state but also in a "dark" state. In "bright" mode, when an image is displayed on the screen, the sides of the LCD may suffer from reduced brightness, viewing angle distortion, and color inaccuracy compared to the front of the display. Conversely, in "dark" mode, LCDs may experience poor black visibility, caused by light leakage leading to reduced screen uniformity along the diagonal and sides, resulting in observable spots. In dark mode, the LCD panel has significantly lower brightness than in bright mode. Therefore, even if an LCD has improved viewing angles in bright mode, improved black visibility in dark mode cannot be guaranteed.

[0006] As a method to improve black visibility, an anti-reflective film, a low-reflective film, or an ultra-low-reflective film can be stacked on the surface where external light first strikes. However, this method cannot fundamentally prevent light leakage caused by the backlight of the liquid crystal display device.

[0007] The background technology of the present invention is disclosed in Korean Patent Publication No. 2018-0047569, etc. Summary of the Invention

[0008] One aspect of the present invention is to provide a liquid crystal display device having improved black visibility and appearance in a dark operating state.

[0009] Another aspect of the present invention is to provide a liquid crystal display device having an improved viewing angle (especially the left and right viewing angle) on its sides in a bright operating state.

[0010] One aspect of the present invention relates to a liquid crystal display device.

[0011] Example 1: The liquid crystal display device includes: a liquid crystal panel; a viewer-side polarizing plate stacked on the light emitting surface of the liquid crystal panel; and a first optical sheet and a second optical sheet stacked sequentially on the light incident surface of the liquid crystal panel, wherein the viewer-side polarizing plate includes a polarizer; and a contrast ratio or viewing angle-enhancing layer; the liquid crystal panel has a horizontal direction corresponding to its long side and a vertical direction corresponding to its short side; and the first optical sheet has a plurality of first optical patterns on its light emitting surface, the angle between the longitudinal direction of the first optical patterns and the vertical direction of the liquid crystal panel is in the range of -10° to +10°.

[0012] Example 2: In Example 1, the first optical sheet can be a sheet that collects light in the left-right direction, and the second optical sheet can be a sheet that collects light in the up-down direction.

[0013] Example 3: In Examples 1 and 2, the second optical sheet may have a plurality of second optical patterns on its light emitting surface, and the angle between the longitudinal direction of the second optical pattern and the vertical direction of the liquid crystal panel may be in the range of 80° to 100°.

[0014] Example 4: In Example 3, the first optical pattern may have a vertex angle α of 70° to 120°, and the second optical pattern may have a vertex angle β of 70° to 120°.

[0015] Example 5: In Examples 1 to 4, each of the first optical pattern and the second optical pattern may have a strip shape extending in its longitudinal direction.

[0016] Example 6: In Examples 1 to 5, the angle between the longitudinal direction of the first optical pattern and the light absorption axis of the polarizer can be in the range of -10° to 10° or 80° to 100°.

[0017] Example 7: In Examples 1 to 6, the contrast or viewing angle enhancement layer may include at least one of a patterned contrast enhancement layer and an unpatterned contrast enhancement layer.

[0018] Example 8: In Example 7, the patterned contrast enhancement layer may include a first resin layer and a second resin layer with a different refractive index relative to the first resin layer, and a patterned portion having at least one engraved optical pattern may be formed at the interface between the first resin layer and the second resin layer.

[0019] Example 9: In Example 8, the angle between the longitudinal direction of the engraved optical pattern and the vertical direction of the liquid crystal panel can be in the range of -10° to +10°.

[0020] Example 10: In Example 8, the engraved optical pattern may have a higher aspect ratio than the first optical pattern.

[0021] Example 11: In Examples 8 to 10, the aspect ratio of the engraved optical pattern can be 0.3 or greater than 0.3.

[0022] Example 12: In Examples 8 to 11, the engraved optical pattern may have a first surface formed at its top and two sides connected to the first surface, and each of the sides may have at least one flat surface or a curved surface.

[0023] Example 13: In Examples 8 to 12, the patterned portion may further include a flat section located between adjacent engraved optical patterns.

[0024] Example 14: In Examples 8 to 13, the refractive index difference between the first resin layer and the second resin layer may be 0.2 or less than 0.2.

[0025] Example 15: In Examples 7 to 14, the unpatterned contrast enhancement layer may include a monolayer containing a matrix and an optically anisotropic material aligned in the matrix.

[0026] Example 16: In Example 15, the alignment angle of the optical anisotropic material relative to the vertical direction of the liquid crystal panel can be in the range of 65° to 115° or -25° to 25°.

[0027] Example 17: In Examples 15 and 16, the optical anisotropic material may have a linear shape, a fiber shape, or a needle shape.

[0028] Example 18: In Examples 15 to 17, the optical anisotropic material may include at least one selected from wires and needle-like particles, wherein the wires are formed from at least one selected from metals, nonmetals, metal oxides, nonmetal oxides, metal sulfides, nonmetal sulfides, metal nitrides, nonmetal nitrides, metal hydroxides, nonmetal hydroxides, and glass, and the needle-like particles are formed from at least one selected from titanium dioxide, zirconium oxide, zinc oxide, calcium carbonate, boehmite, aluminum borate, calcium silicate, magnesium sulfate, magnesium sulfate hydrate, potassium titanate, glass, and synthetic resin.

[0029] Example 19: In Examples 1 to 18, the viewer-side polarizing plate may not contain at least one of the anti-reflection layer, low-reflection layer, and ultra-low-reflection layer.

[0030] The present invention provides a liquid crystal display device with improved black visibility and appearance in dark operation.

[0031] The present invention provides a liquid crystal display device having an improved viewing angle (specifically, the left and right viewing angle) on its sides in a bright operating state. Attached Figure Description

[0032] Figure 1 This is a partial cross-sectional view of a liquid crystal display device according to an embodiment of the present invention.

[0033] Figure 2 yes Figure 1 The diagram shows a concept image of a liquid crystal panel, a first optical element, and a second optical element.

[0034] Figure 3 yes Figure 1 A partial cross-sectional view of one embodiment of the viewer-side polarizer shown.

[0035] Figure 4 yes Figure 3 A cross-sectional view of another embodiment of the engraved optical pattern shown.

[0036] Figure 5 yes Figure 1 A partial cross-sectional view of another embodiment of the viewer-side polarizer shown. Detailed Implementation

[0037] In the following description, embodiments of the invention will be illustrated with reference to the accompanying drawings to enable those skilled in the art to readily implement the invention. It should be understood that the invention may be implemented in different ways and is not limited to the following embodiments.

[0038] In the accompanying drawings, components unrelated to the description are omitted for clarity of the invention, and the same components will be represented by the same reference numerals throughout the specification.

[0039] In this document, spatial relative terms such as "upper" and "lower" are defined with reference to the accompanying drawings. Therefore, it should be understood that "upper surface" and "lower surface" are used interchangeably, and when an element is said to be placed "on" another element, it may be placed directly on said other element, or there may be intermediate elements present. When an element is said to be placed "directly" on another element, there are no intermediate elements present.

[0040] In this paper, the "in-plane delay (Re)" is the value measured at a wavelength of 550 nm, calculated according to Equation A:

[0041] [Equation A]

[0042] Re = (nx - ny) × d

[0043] Where nx and ny are the refractive indices of the protective film or layer at a wavelength of 550 nm along its slow axis and fast axis, respectively, and d is the thickness of the protective film or layer (unit: nm).

[0044] In this article, "(meth)acryloyl" refers to acryloyl and / or methacryloyl.

[0045] In this article, “X to Y” is used to represent a specific numerical range, meaning “X ≤ and ≤ Y”.

[0046] This invention provides a liquid crystal display device that improves lateral viewing angles (especially left and right viewing angles) in bright operation while providing a good appearance by improving black visibility in dark operation. In particular, the liquid crystal display device can improve black visibility even when there is no surface treatment layer (e.g., anti-reflective layer, low-reflective layer, or ultra-low-reflective layer) on the viewer-side polarizer.

[0047] In this paper, both "bright operating state" and "dark operating state" are defined relative to the liquid crystal display device in the on state. Since the liquid crystal display device operates when a voltage is applied to it, the brightness of the liquid crystal display device is determined by the voltage applied to it. An 8-bit signal, categorized into gray levels from 0 to 255 based on the minimum to maximum operating voltage, is sent to the liquid crystal panel. Assuming that the gray level input to the entire front and side of the liquid crystal panel is 0, the brightness value is defined as "0 gray level (black) brightness," and when the gray level input to the liquid crystal panel is 255, the brightness value is defined as "255 gray level (white) brightness." Bright operating state means that the gray level input to the panel is in the range of 33 to 255, and dark operating state means that the gray level input to the panel is in the range of 0 to less than 33. The "operating brightness" of the panel can be measured in cd / m² using physical photometry. 2 In this method, a luminance meter is used to measure the actual brightness of the panel in response to a panel input signal, and the brightness values ​​from 0 gray level (black) to 255 gray level (white) are determined based on the actual brightness curve of the panel in response to the input signal at each gray level of the panel.

[0048] The liquid crystal display device includes: a liquid crystal panel; a viewer-side polarizing plate stacked on the light-emitting surface of the liquid crystal panel; and a first optical sheet and a second optical sheet stacked sequentially on the light-incident surface of the liquid crystal panel, wherein the viewer-side polarizing plate includes a polarizer and a contrast or viewing angle enhancement layer; the liquid crystal panel has a horizontal direction corresponding to its long side and a vertical direction corresponding to its short side; and the first optical sheet has a plurality of first optical patterns on its light-emitting surface, and the angle between the longitudinal direction of the first optical patterns and the vertical direction of the liquid crystal panel is in the range of -10° to +10°. Since the angle between the longitudinal direction of the first optical patterns and the vertical direction of the liquid crystal panel is set in the range of -10° to +10°, it is easy to simultaneously improve both the left and right viewing angles and black level visibility. Preferably, the angle is in the range of -5° to +5°, more preferably 0°. In the description of angles, "+" means the angle in the clockwise direction relative to the reference point (i.e., the direction perpendicular to the short side of the LCD panel), while "-" means the angle in the counterclockwise direction relative to the reference point (i.e., the direction perpendicular to the short side of the LCD panel).

[0049] Next, we will refer to Figures 1 to 5 To describe a liquid crystal display device.

[0050] The liquid crystal display device includes a liquid crystal panel 100, a viewer-side polarizing plate 200 and 300, a light source-side polarizing plate 600, a first optical film 400, and a second optical film 500.

[0051] LCD panel

[0052] The liquid crystal panel 100 has a light emitting surface and a light incident surface facing each other. The light incident surface is from a light source disposed below the lower surface of the second optical sheet. Figure 1 The light emitted (internal light) from the liquid crystal panel (not shown) enters the liquid crystal panel through its plane. The light emitting surface is the plane through which the light that has entered the liquid crystal panel exits towards the viewer-side polarizer.

[0053] The liquid crystal panel 100 has a rectangular shape formed by a long side corresponding to the horizontal direction 101 and a short side corresponding to the vertical direction 102. The horizontal direction 101 is substantially orthogonal to the vertical direction 102.

[0054] The liquid crystal panel 100 may employ a typical liquid crystal known to those skilled in the art. For example, the liquid crystal may include at least one selected from vertical alignment (VA) mode, in-plane switching (IPS) mode, twisted nematic (TN) mode, fringe field switching (FFS) mode, patterned vertical alignment (PVA) mode, and super-patterned vertical alignment (S-PVA) mode, but is not limited thereto.

[0055] First optical plate and second optical plate

[0056] The first optical sheet 400 and the second optical sheet 500 are sequentially stacked on the light incident surface of the liquid crystal panel 100. Each of the first optical sheet 400 and the second optical sheet 500 can emit light after collecting light emitted from the light source, thereby improving the luminous efficiency.

[0057] The first optical sheet 400 and the second optical sheet 500 may have different light-collecting functions. In one embodiment, the first optical sheet 400 may act as a lateral light-collecting sheet (i.e., a sheet that collects light emitted from the light source in the left-right direction), and the second optical sheet 500 may act as a vertical light-collecting sheet (i.e., a sheet that collects light emitted from the light source in the up-down direction). A lateral light-collecting sheet means a sheet that has the function of collecting light emitted from the light source in the horizontal direction 101 corresponding to the long side of the liquid crystal panel 100. A vertical light-collecting sheet means a sheet that has the function of collecting light emitted from the light source in the vertical direction 102 corresponding to the short side of the liquid crystal panel 100. The liquid crystal display device includes both the first optical sheet 400 and the second optical sheet 500, wherein the first optical sheet 400 corresponding to the lateral light-collecting sheet is disposed closer to the liquid crystal panel 100 than the second optical sheet 500 corresponding to the vertical light-collecting sheet, thereby improving black visibility and appearance.

[0058] The first optical sheet 400 has a plurality of first optical patterns 401 disposed on the light emitting surface 402, wherein the longitudinal direction of the first optical patterns 401 (in Figure 2The angle (A) relative to the vertical direction 102 of the liquid crystal panel 100 (indicated by the solid arrow) is in the range of -10° to +10°. Within this range, the liquid crystal display device can exhibit significant improvements in black level visibility and lateral viewing angle. For example, the angle (A) can be -10°, -9°, -8°, -7°, -6°, -5°, -4°, -3°, -2°, -1°, 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, or 10°, preferably -5° to +5°, and more preferably 0°.

[0059] Typical surface treatment layers, such as anti-reflective layers, low-reflective layers, or ultra-low-reflective layers, are used to prevent deterioration of black visibility and appearance due to light leakage into the liquid crystal display device driven in a "dark" operating state. According to the present invention, even without applying a typical surface treatment layer to the viewer-side polarizer, by adjusting the angle of the longitudinal direction of the first optical pattern relative to the vertical direction of the liquid crystal panel in a lateral light-collecting layer with lateral light-collecting function among a plurality of optical sheets disposed on the light source side of the liquid crystal panel, the liquid crystal panel provides a good appearance by improving black visibility in a "dark" operating state.

[0060] Specifically, according to the present invention, a first optical sheet providing lateral light collection function and a second optical sheet providing vertical light collection function are sequentially stacked on the light incident surface of the liquid crystal panel, instead of using a viewer-side polarizer on the light emitting surface of the liquid crystal panel to improve black visibility, wherein the angle defined between the longitudinal direction of the first optical pattern of the first optical sheet and the vertical direction of the liquid crystal panel can be adjusted.

[0061] Furthermore, according to the present invention, the viewer-side polarizing plate is provided with a contrast or viewing angle enhancement layer to achieve a significant improvement in the contrast and viewing angle of the front and sides in both bright and dark operating states by adjusting the aforementioned angle.

[0062] In the first optical sheet, a plurality of first optical patterns 401 are formed on the light emitting surface 402 corresponding to the upper surface of the first optical sheet 400, while no optical patterns are formed on the light incident surface 403 corresponding to the lower surface of the first optical sheet 400, thereby the lower surface of the first optical sheet can be made approximately flat.

[0063] The first optical pattern 401 may be an optical pattern having a polygonal cross-section, wherein the apex angle α of the polygon is from 70° to 120°, for example, 70°, 71°, 72°, 73°, 74°, 75°, 76°, 77°, 78°, 79°, 80°, 81°, 82°, 83°, 84°, 85°, 86°, 87°, 88°, 89°, 90°, 91°, The first optical pattern 401 can be within the range of 92°, 93°, 94°, 95°, 96°, 97°, 98°, 99°, 100°, 101°, 102°, 103°, 104°, 105°, 106°, 107°, 108°, 109°, 110°, 111°, 112°, 113°, 114°, 115°, 116°, 117°, 118°, 119°, or 120°. Within this range, when applied to the second optical sheet described below, the first optical pattern 401 can further improve the left and right viewing angles. "Apex angle" refers to the angle defined at the top portion of a polygon among its multiple angles. The polygon can be an n-sided polygon (n is an integer from 3 to 10), such as a triangle, quadrilateral, pentagon, hexagon, etc., preferably a triangle. Here, the top portion refers to the highest part of the first optical pattern.

[0064] As shown in the figure, the first optical pattern 401 may have a strip shape extending in its longitudinal direction.

[0065] The aspect ratio (ratio of height H1 to width W1) of the first optical pattern 401 can be from 0.1 to 10, for example 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5 or 10.0, preferably from 0.3 to 1.0, and more preferably from 0.3 to 0.9. Within this range, the first optical pattern 401 can provide a light-collecting effect. The width W1 of the first optical pattern 401 can be from 10 μm to 200 μm, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm or 200 μm, preferably from 40 μm to 150 μm. Furthermore, the height H1 of the first optical pattern 401 can be from 10 μm to 200 μm, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, or 200 μm, preferably from 20 μm to 50 μm. Within this range, the liquid crystal display device can easily achieve the aspect ratio of the present invention, while easily improving black visibility.

[0066] The first optical patterns 401 may be arranged continuously without any separating distance between them. Alternatively, the first optical patterns 401 may be arranged at specific intervals to have a separating distance between adjacent first optical patterns. Preferably, the first optical patterns are arranged continuously without any separating distance between them to further improve the effectiveness of the invention.

[0067] In one embodiment, the spacing between adjacent first optical patterns 401 can be in the range of 0 μm to 100 μm, preferably in the range of 0 μm to 20 μm. Within this range, the first optical sheet according to the invention can be easily manufactured.

[0068] As shown in the figure, the first optical sheet 400 may further include a base layer 404 formed on the lower surface of the first optical pattern and having a predetermined thickness, or it may consist only of the first optical pattern without a base layer. Furthermore, the first optical sheet 400 may be formed directly on the second optical sheet, or it may be formed directly below or above the reflective polarizing film.

[0069] The second optical sheet 500 may have a plurality of second optical patterns 501 on its light emitting surface 502, wherein the longitudinal direction of the second optical pattern 501 (in Figure 2 The angle (B) of the second optical element 500 relative to the vertical direction 102 of the liquid crystal panel 100 (indicated by the dashed line) is between 80° and 100°. Within this range, the second optical element 500 can achieve significant improvements in lateral viewing angle and black level visibility. For example, the angle (B) can be 80°, 81°, 82°, 83°, 84°, 85°, 86°, 87°, 88°, 89°, 90°, 91°, 92°, 93°, 94°, 95°, 96°, 97°, 98°, 99° or 100°, preferably 90°.

[0070] According to the present invention, a second optical sheet 500 providing vertical light collection function is disposed on the lower surface of the first optical sheet 400, thereby further improving the side viewing angle and black visibility by adjusting the angle (B) of the longitudinal direction of the second optical pattern 501 relative to the vertical direction 102 of the liquid crystal panel.

[0071] In the second optical sheet 500, the light emitting surface 502 corresponding to the upper surface of the second optical sheet 500 is formed with the plurality of second optical patterns 501, while the light incident surface 503 corresponding to its lower surface is substantially flat, thereby making the lower surface substantially flat.

[0072] The second optical pattern 501 may have a polygonal cross-section, wherein the apex angle β of the polygon is 70° to 120°. Within this range, when applied to the first optical sheet described above, the second optical pattern 501 can further improve the left and right viewing angles. "Apex angle" refers to the angle defined at the top portion of the polygon. The polygon may be an n-sided polygon (n is an integer from 3 to 10), such as a triangle, quadrilateral, pentagon, hexagon, etc., preferably a triangle. For example, the apex angle may be 70°, 71°, 72°, 73°, 74°, 75°, 76°, 77°, 78°, 79°, 80°, 81°, 82°, 83°, 84°, 85°, 86°, 87°, 88°, 89°, 90°, 91°, 92°, 93°, 94°, 95°, 96°, 97°, 98°, or 99°. 100°, 101°, 102°, 103°, 104°, 105°, 106°, 107°, 108°, 109°, 110°, 111°, 112°, 113°, 114°, 115°, 116°, 117°, 118°, 119° or 120°, preferably 80° to 100°, more preferably 90°.

[0073] As shown in the figure, the second optical pattern 501 may have a strip shape extending in its longitudinal direction.

[0074] The aspect ratio (ratio of height H2 to width W2) of the second optical pattern 501 can be from 0.1 to 10, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, or 10.0, preferably from 0.3 to 1.0, and more preferably from 0.3 to 0.9. Within this range, the second optical sheet can ensure light collection effect.

[0075] The width W2 of the second optical pattern 501 can be from 10 μm to 200 μm, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm or 200 μm, preferably from 40 μm to 150 μm. Furthermore, the height H2 of the second optical pattern 501 can be from 10 μm to 200 μm, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, or 200 μm, preferably from 20 μm to 50 μm. Within this range, the liquid crystal display device can easily achieve the aspect ratio of the present invention, while easily improving black level visibility.

[0076] The second optical patterns 501 may be arranged continuously without any separating distance between them. Alternatively, the second optical patterns 501 may be arranged at specific intervals to have a separating distance between adjacent second optical patterns. Preferably, the second optical patterns 501 are arranged continuously without any separating distance between them.

[0077] In one embodiment, the spacing between adjacent second optical patterns 501 can be in the range of 0 μm to 100 μm, preferably 0 μm to 20 μm. Within this range, the second optical sheet according to the invention can be easily manufactured.

[0078] As shown in the figure, the second optical sheet 500 may also include a base layer 504 formed on the lower surface of the second optical pattern and having a predetermined thickness, or may consist only of the second optical pattern.

[0079] The first optical sheet 400 and the second optical sheet 500 can be stacked without an adhesive layer between them. Alternatively, an adhesive layer can be further formed between the first optical sheet 400 and the second optical sheet 500.

[0080] The first optical sheet 400 and the second optical sheet 500 may be formed from typical photocurable resin compositions used for optical sheets. The photocurable resin composition may contain typical materials known to those skilled in the art.

[0081] Viewer-side polarizer

[0082] Viewer-side polarizers 200 and 300 are stacked on the light-emitting surface of the LCD panel and emit light received from the LCD panel, which is used to improve the contrast of both the front and the sides, as well as improve the left and right viewing angles.

[0083] Viewer-side polarizing plates 200, 300 include polarizers 210, 310 and contrast enhancement layers 220, 320. Contrast enhancement layers 220, 320 may be stacked on the light-emitting surface or the light-incident surface of polarizers 210, 310. Preferably, the contrast enhancement layers are stacked on the light-emitting surface of the polarizer. The light-emitting surface refers to the surface from which the polarizer emits light (from the light source). Figure 1 The light emitted (internal light) from the polarizer (not shown) passes through the plane from which it originates. The light incident surface refers to the plane through which the light that has entered the liquid crystal panel passes into the polarizer.

[0084] The contrast enhancement layer may include at least one of a patterned contrast enhancement layer 220 having patterned portions and an unpatterned contrast enhancement layer 320 without patterned portions.

[0085] According to this embodiment, the liquid crystal display device may include... Figure 3 , Figure 4 and Figure 5 Any of the viewer-side polarizers shown can be used as the viewer-side polarizer. (Refer to...) Figure 3 , Figure 4 and Figure 5 Each of these will describe the viewer-side polarizer.

[0086] Reference Figure 3 The viewer-side polarizer includes a polarizer 210; and a patterned contrast enhancement layer 220 and a first protective layer 230 stacked on the light-emitting surface of the polarizer 210.

[0087] The patterned contrast enhancement layer 220 includes a first resin layer 221 and a second resin layer 222 having different refractive indices, and a patterned portion is formed at the interface between the first resin layer 221 and the second resin layer 222. The patterned portion may include an engraved optical pattern 223 having a predetermined cross-section and a flat segment 224 formed between adjacent engraved optical patterns 223.

[0088] The refractive index difference between the first resin layer 221 and the second resin layer 222 can be 0.2 or less, for example, 0.1 to 0.2. Within this range, the patterned contrast enhancement layer can help improve the left and right viewing angles.

[0089] The first resin layer 221 and the second resin layer 222 are stacked sequentially on the light emitting surface of the polarizer 210, and the first resin layer may have a higher or lower refractive index than the second resin layer.

[0090] Preferably, the first resin layer has a lower refractive index than the second resin layer. In one embodiment, the refractive index of the first resin layer may be less than 1.53, for example, from 1.30 to less than 1.53, and the refractive index of the second resin layer may be 1.53 or greater than 1.53, for example, from 1.53 to 1.70.

[0091] The patterned portion can satisfy Equation 1 below, and each of the engraved optical patterns 223 can have a base angle θ of 75° to 90°. Within this range, the patterned contrast enhancement layer can help improve the left and right viewing angles.

[0092] 1 <P / W3≤10,---(1)

[0093] Where P is the spacing of the patterned portion (unit: μm), and

[0094] W3 is the maximum width (in μm) of the engraved optical pattern.

[0095] The base angle θ refers to the angle defined between the inclined side 226 of the engraved optical pattern 223 and the maximum width W3 of the engraved optical pattern 223. Preferably, the base angle θ is in the range of 80° to 90°, and P / W3 in Equation 1 is in the range of 1.2 to 8.

[0096] The engraved optical pattern 223 may include an optical pattern protruding from the first resin layer 221 to the second resin layer 222.

[0097] The engraved optical pattern 223 can have a higher aspect ratio than the first optical pattern 401. Using this structure, the liquid crystal display device can easily achieve the effects of the present invention.

[0098] In one embodiment, the aspect ratio (the ratio of maximum height H3 to maximum width W3) of the engraved optical pattern 223 can be 0.3 or greater than 0.3. Within this range, the engraved optical pattern 223 can help improve the left and right viewing angles. Preferably, the aspect ratio of the engraved optical pattern 223 is 0.6 or greater than 0.6, more preferably 1.0 to 2, and most preferably greater than 1.0 and less than 2. According to the present invention, when the aspect ratio of the engraved optical pattern is 0.3 or greater than 0.3, the liquid crystal display device can achieve significant improvements in left and right viewing angles and black level visibility.

[0099] The maximum width W3 of the engraved optical pattern 223 can be from 3 μm to 50 μm, preferably from 5 μm to 30 μm, and the maximum height H3 of the engraved optical pattern 223 can be from 3 μm to 50 μm, preferably from 5 μm to 20 μm. Within this range, the engraved optical pattern can easily achieve the aspect ratio of the present invention, while significantly improving the left and right viewing angles and black level visibility of the liquid crystal display device.

[0100] Each of the engraved optical patterns 223 may have a first surface 225 formed at its top portion and two inclined sides 226 connected to the first surface 225.

[0101] Light that has entered the engraved optical pattern 223 is emitted through the first surface 225, thereby increasing brightness. The first surface 225 may be a generally flat surface, or it may be convex or concave. The maximum width of the first surface 225 may be from 1 μm to 40 μm, preferably from 3 μm to 25 μm. Within this range, the engraved optical pattern 223 can improve the left and right viewing angles of the liquid crystal display device without degrading the front brightness.

[0102] Each of the sides 226 may be composed of one or more flat surfaces (e.g., 1 to 3 flat surfaces).

[0103] In one embodiment, such as Figure 3 As shown, each of the sides may be formed by a flat surface.

[0104] In another embodiment, such as Figure 4 As shown, each of the sides may be composed of two or more flat surfaces, each of which may have a different base angle θ relative to the maximum width of the engraved optical pattern 223. Here, the base angle θ refers to the angle defined between the corresponding flat surface of the side and the maximum width W3 of the engraved optical pattern 223. Each of the sides may be a convex polygonal surface protruding from the first resin layer to the second resin layer. Figure 4 (A) or a concave polygonal surface protruding from the first resin layer to the second resin layer. Figure 4(B)). The base angle θ can be in the range of 60° to 90°, for example, in the range of 75° to 90°. Within this range, the effects of the present invention can be easily achieved.

[0105] For example, the engraved optical pattern 223 may have an N-sided cross-section (N is an integer from 3 to 10), such as a trapezoidal cross-section, a rectangular cross-section, or a square cross-section.

[0106] Each of the sides may be composed of one or more curved surfaces (e.g., 1 to 3 curved surfaces).

[0107] In one embodiment, such as Figure 4 As shown, each of the sides may be formed by a curved surface. In another embodiment, as... Figure 4 As shown, each of the sides may be composed of two or more curved surfaces, each of which may have a different base angle θ relative to the maximum width of the engraved optical pattern 223. Here, the base angle θ refers to the angle defined between the tangent T of the corresponding curved surface at half the maximum height H3 of the engraved optical pattern 223 and the maximum width W3 of the engraved optical pattern 223.

[0108] Here, each of the sides may be a convex curved surface protruding from the first resin layer to the second resin layer. Figure 4 (C)) or a concave curved surface protruding from the first resin layer to the second resin layer ( Figure 4 (D)). The bottom angle can be between 60° and 90°, for example, between 75° and 90°. Within this range, the liquid crystal display device can easily achieve the effects of the present invention.

[0109] The spacing P of the patterned portions can range from 5 μm to 500 μm, specifically from 10 μm to 50 μm. Within this range, the patterned portions can readily satisfy Equation 1 and can be readily formed. Here, the spacing P refers to the sum of the maximum width W3 of an engraved optical pattern and the maximum width L of the separating surface between adjacent engraved optical patterns.

[0110] Adjacent etched optical patterns 223 can be spaced apart from each other by flat sections 224. The flat sections 224 allow light received perpendicularly from the polarizer to pass through, thereby improving brightness. The maximum width L of the flat sections 224 can range from 1 μm to 40 μm, specifically from 3 μm to 25 μm. Within this range, the etched optical patterns can improve the viewing angle of the liquid crystal display device while minimizing the loss of front-side brightness.

[0111] although Figure 3 Not shown, but each of the engraved optical patterns 223 can be formed as a strip shape extending in its longitudinal direction.

[0112] In one embodiment, the angle (C) of the longitudinal direction of the engraved optical pattern 223 relative to the vertical direction of the liquid crystal panel corresponding to its shorter side can be in the range of -10° to +10°. Since the angle of the longitudinal direction of the engraved optical pattern 223 relative to the vertical direction of the liquid crystal panel is in the range of -10° to +10°, the liquid crystal display device can easily achieve simultaneous improvement in both left and right viewing angles and black level visibility. For example, the angle (C) can be -10°, -9°, -8°, -7°, -6°, -5°, -4°, -3°, -2°, -1°, 0°, +1°, +2°, +3°, +4°, +5°, +6°, +7°, +8°, ​​+9°, or +10°, preferably -5° to +5°, and more preferably 0°.

[0113] The first resin layer 221 may have a filling pattern 227 that fills at least a portion of the engraved optical pattern 223.

[0114] Polarizer 210 is used to polarize light received from the liquid crystal panel to emit polarized light that passes through the patterning layer.

[0115] Polarizer 210 may include a polyvinyl alcohol-based polarizer formed by uniaxial stretching of a polyvinyl alcohol film or a polyene-based polarizer formed by dehydrating a polyvinyl alcohol film. Polarizers can be manufactured using polyvinyl alcohol films using typical methods known to those skilled in the art.

[0116] The thickness of polarizer 210 can range from 5 μm to 40 μm. Within this range, polarizers can be used in optical displays.

[0117] In the first optical sheet, the angle (D) of the longitudinal direction of the first optical pattern relative to the light absorption axis of the polarizer 210 can be between -10° and 10° or between 80° and 100°, for example, -10°, -9°, -8°, -7°, -6°, -5°, -4°, -3°, -2°, -1°, 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 81°, 82°, 83°, 84°, 85°, 86°, 87°, 88°, 89°, 90°, 91°, 92°, 93°, 94°, 95°, 96°, 97°, 98°, 99° or 100°, preferably between -5° and 5° or between 85° and 95°. Within this range, the liquid crystal display device can easily achieve the effects of the present invention. Here, the light absorption axis of polarizer 210 corresponds to the machine direction of polarizer 210.

[0118] The first protective layer 230 may be a light-transmitting layer, allowing light propagating through the patterned layer to pass through it.

[0119] The first protective layer 230 may be a retardation film or an isotropic film providing a phase difference within a predetermined range. In one embodiment, the in-plane retardation Re of the first protective layer may be 8,000 nm or greater than 8,000 nm, specifically 10,000 nm or greater than 10,000 nm, more specifically greater than 10,000 nm, and even more specifically from 10,100 nm to 15,000 nm. Within this range, the protective layer can prevent the observation of rainbow spots and can further improve the propagation of light that has passed through the second resin layer and the first resin layer. In another embodiment, the first protective layer may be an isotropic film with an in-plane retardation Re of 60 nm or less (specifically from 0 nm to 60 nm, more specifically from 40 nm to 60 nm). Within this range, the first protective layer can improve image quality by compensating for viewing angle. Here, an isotropic film means a film in which nx, ny, and nz all have substantially the same values, and "substantially the same" means not only that the retardation values ​​are exactly the same, but also that there are slight differences among them. Preferably, the in-plane retardation Re of the first protective layer is 8,000 nm or greater than 8,000 nm, specifically 10,000 nm or greater than 10,000 nm, and more specifically greater than 10,000 nm.

[0120] The thickness of the first protective layer 230 can be from 20 μm to 120 μm, specifically from 30 μm to 80 μm. Within this range, the first protective layer can be applied to an optical display. The light transmittance of the first protective layer 230 in the visible spectrum can be 80% or greater than 80%, specifically from 85% to 95%. The first protective layer 230 may comprise a film prepared by uniaxial or biaxial stretching of an optically transparent resin. Specifically, the resin may include at least one of the following: polyesters, including polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, etc.; acrylic; cyclic olefin polymers (COP); cellulose esters, including triacetyl cellulose (TAC), etc.; polyvinyl acetate; polyvinyl chloride (PVC); polynorbornene; polycarbonate (PC); polyamide; polyacetal; polyphenylene ether; polyphenylene sulfide; polysulfone; polyethersulfone. The protective layer comprises a film formed of a polyester resin. The first protective layer may comprise a film manufactured by modifying the aforementioned resin. Modification may include copolymerization, branching, cross-linking, or modification of the molecular ends.

[0121] Although Figure 3 Not shown, but a functional coating may be further formed on at least one surface of the first protective layer 230 to provide additional functionality. The functional coating may be a primer layer, a hard coating, or an anti-fingerprint layer, but is not limited thereto.

[0122] Reference Figure 5 To describe the viewer-side polarizer including an unpatterned contrast enhancement layer.

[0123] Reference Figure 5 The viewer-side polarizer 300 includes a polarizer 310; and an unpatterned contrast enhancement layer 320 and a first protective layer 330 sequentially stacked on the light-emitting surface of the polarizer 310.

[0124] Polarizer 310 and first protective layer 330 with Figure 3 The polarizer 210 and the first protective layer 230 shown are substantially the same. The angle (D) of the longitudinal direction of the first optical pattern relative to the light absorption axis of the polarizer 310 can be between -10° and 10° or between 80° and 100°, for example, -10°, -9°, -8°, -7°, -6°, -5°, -4°, -3°, -2°, -1°, 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 81°, 82°, 83°, 84°, 85°, 86°, 87°, 88°, 89°, 90°, 91°, 92°, 93°, 94°, 95°, 96°, 97°, 98°, 99° or 100°, preferably between -5° and 5° or between 85° and 95°. Within this scope, liquid crystal display devices can easily achieve the effects of the present invention.

[0125] The following explanation will focus only on the unpatterned contrast enhancement layer 320.

[0126] The unpatterned contrast enhancement layer 320 consists of a single layer comprising a matrix, and each of its upper and lower surfaces is a generally flat surface. Although unlike contrast enhancement layer 220, the unpatterned contrast enhancement layer 320 does not include patterned portions, it does include an optically anisotropic material 321, which is aligned within the matrix to provide improved contrast and viewing angle.

[0127] The alignment angle (C) of the optically anisotropic material relative to the direction perpendicular to the short side of the liquid crystal panel can be between 65° and 115° or between -25° and 25°. Within this range, the liquid crystal display device can easily achieve simultaneous improvement in both left and right viewing angles and black level visibility. For example, angle C can be 65°, 66°, 67°, 68°, 69°, 70°, 71°, 72°, 73°, 74°, 75°, 76°, 77°, 78°, 79°, 80°, 81°, 82°, 83°, 84°, 85°, 86°, 87°, 88°, 89°, 90°, 91°, 92°, 93°, 94°, 95°, 96°, 97°, 98°, 99°, 100°, 101°, 102°, 103°, 104°, 105°, 106°, 107°, 108°, 109°, 110°, 111°, 112°, 113°, 114°, 115°, or -25°. -24°, -23°, -22°, -21°, -20°, -19°, -18°, -17°, -16°, -15°, -14°, -13°, -12°, -11°, -10°, -9°, -8°, -7°, -6°, -5°, -4°, -3°, -2°, -1°, 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24° or 25°, preferably 85° to 95° or -5° to +5°, more preferably 0°. In one embodiment, of all the optically anisotropic material, 60% by weight or more (e.g., 85% to 95% by weight) of the optically anisotropic material may be aligned in the unpatterned contrast enhancement layer 320 at the aforementioned angle (C).

[0128] Optical anisotropic materials can have wire, fiber, or needle shapes. When forming an unpatterned contrast enhancement layer, such a shape can help achieve the effects of the present invention by allowing the optical anisotropic materials to align at the aforementioned angles.

[0129] In the unpatterned contrast enhancement layer, the content of optical anisotropic material can be from 1 wt% to 40 wt%, specifically from 1 wt% to 30 wt%, 3 wt% to 15 wt%, 4 wt% to 15 wt%, and more specifically from 4 wt% to 10 wt%. Within this range, the optical anisotropic material can help improve contrast and visibility. The optical anisotropic material can be formed from at least one of the following: metals, nonmetals, metal oxides, nonmetal oxides, metal sulfides, nonmetal sulfides, metal nitrides, nonmetal nitrides, metal hydroxides, nonmetal hydroxides, glass, titanium dioxide, zirconium oxide, zinc oxide, calcium carbonate, boehmite, aluminum borate, calcium silicate, magnesium sulfate, magnesium sulfate hydrate, potassium titanate, and synthetic resins.

[0130] Lines can have a length much larger than their diameter to help improve contrast and visibility.

[0131] In one embodiment, the line may be a nanowire or microwire, and its aspect ratio (the ratio of length to diameter) may be 500 or less, specifically 200 or less, more specifically 5 to 200, and even more specifically 10 to 100. Within this range, the line can help improve contrast and visibility, while also aiding in its alignment.

[0132] The wire can be a nanowire or a microwire, and its cross-sectional diameter can be 20 μm or less than 20 μm, specifically greater than 0 μm to 20 μm or less than 20 μm, more specifically 0.1 μm to 20 μm, and even more specifically 0.5 μm to 1 μm. The length of the wire can be 1 μm or greater than 1 μm, specifically 5 μm to 4,000 μm, and more specifically 10 μm to 1,000 μm. Within this range, the wire can easily achieve the above aspect ratios. In this document, "cross-sectional diameter" refers to its maximum cross-sectional diameter.

[0133] In the unpatterned contrast enhancement layer 320, the line content can be from 1 wt% to 40 wt%, specifically from 3 wt% to 15 wt%, and more specifically from 4 wt% to 10 wt%. Within this range, the lines help improve contrast and visibility.

[0134] The line may have a higher or lower refractive index than the matrix. Preferably, the line has a higher refractive index than the matrix to help improve contrast and visibility without whitening.

[0135] In one embodiment, the line may have a higher refractive index than the matrix, and its refractive index may be 1.5 or greater than 1.5, specifically from 1.5 to 2.3, and more specifically from 1.52 to 2.3. Within this range, the following refractive index difference can be readily achieved.

[0136] In another embodiment, the line may have a lower refractive index than the matrix, and its refractive index may be 1.2 or greater than 1.2, specifically 1.4 to 1.6, and more specifically 1.43 to 1.6. Within this range, the following refractive index difference can be readily achieved.

[0137] The refractive index difference between the line and the matrix can be 0.8 or less, preferably 0.6 or less, and more preferably 0.1 to 0.6. Within this range, the line can further improve contrast and brightness while allowing for improvements in the optical properties of the matrix.

[0138] The lines may include lines formed from at least one of the following: metals, nonmetals, metal oxides, nonmetal oxides, metal sulfides, nonmetal sulfides, metal nitrides, nonmetal nitrides, metal hydroxides, nonmetal hydroxides, and glass. Preferably, the unpatterned contrast enhancement layer includes metal oxide lines to improve contrast and visibility.

[0139] The metal may include at least one selected from silver, gold, zinc, platinum, nickel, copper, aluminum, tungsten, and calcium.

[0140] Nonmetals may include at least one selected from silicon, indium, tin, germanium and carbon.

[0141] The metal oxide may include at least one selected from zinc oxide, copper oxide, aluminum oxide, nickel oxide, tungsten oxide, and calcium oxide.

[0142] Metal sulfides may include at least one selected from silver sulfide, zinc sulfide, nickel sulfide, copper sulfide, aluminum sulfide, and tungsten sulfide.

[0143] The unpatterned contrast enhancement layer may contain a metal and at least one functional group compound having at least two chemical / physical bonds.

[0144] Needle-shaped particles can have a length (L) and a diameter (D), with the diameter (D) being non-uniform along the entire length (L) and gradually decreasing towards both ends of the needle-shaped particle. Needle-shaped particles with non-uniform thickness exhibit optical anisotropy properties, thus allowing light received from the polarizer to be emitted in different directions.

[0145] Needle-like particles can refer to particles with a length on the order of micrometers. The length (L) of a needle-like particle has a value on the order of micrometers. Here, "value on the order of micrometers" means a length (L) of 1 μm or greater. In this invention, the micrometer-scale length of the needle-like particles facilitates their alignment, thereby aiding in the improvement of contrast and brightness. Needle-like nanoparticles with a length (L) on the order of nanometers are not easily aligned, making it difficult to ensure the effectiveness of this invention.

[0146] Preferably, the length (L) of the needle-like particles is from 10 μm to 30 μm, more preferably from 15 μm to 28 μm. Within this range, the needle-like particles can be easily aligned to help improve contrast and brightness.

[0147] The cross-sectional diameter (D) of the needle-like particles can be from 0.5 μm to 2 μm, preferably from 1 μm to 2 μm. Within this range, the needle-like particles can have a high aspect ratio to provide a lateral light diffusion effect. Here, "cross-sectional diameter" refers to its maximum cross-sectional diameter.

[0148] The average aspect ratio of the needle-like particles can be from 5 to 60. Within this range, the needle-like particles can easily ensure improved contrast and brightness. Preferably, the average aspect ratio of the needle-like particles is from 10 to 50, more preferably from 10 to 18. Here, "average aspect ratio" means the average of the aspect ratios measured relative to the needle-like particles, while "aspect ratio" means the ratio of the length of the needle-like particles to their maximum diameter.

[0149] Needle-like microparticles can have a higher refractive index than the matrix. Utilizing this structure, needle-like microparticles can further enhance lateral contrast and brightness.

[0150] The refractive index difference between the needle-like particles and the matrix can be 0.8 or less, preferably 0.5 or less, and more preferably 0.15 to 0.25. Within this range, the needle-like particles can further improve contrast and brightness while improving the optical properties of the matrix.

[0151] The refractive index of the needle-like particles can be from 1.5 to 2.2, preferably from 1.6 to 1.8, and more preferably from 1.65 to 1.7. Within this range, the needle-like particles can have a suitable refractive index relative to the matrix, thereby helping to improve contrast and visibility.

[0152] The needle-like particles may be formed from at least one of the following: metal oxides, such as titanium oxide (e.g., TiO2), zirconium oxide (e.g., ZrO2), zinc oxide (e.g., ZnO); metal compounds, such as calcium carbonate (CaCO3), boehmite, aluminum borate (e.g., AlBO3), calcium silicate (e.g., CaSiO3, wollastonite), magnesium sulfate (MgSO4), magnesium sulfate hydrate (e.g., MgSO4·7H2O), potassium titanate (e.g., K2Ti8O). 17 Inorganic particles, such as glass, and organic particles, such as synthetic resins, are used. Preferably, the needle-like particles are formed of calcium carbonate (CaCO3), which readily achieves the effects of the invention and makes it easy to manufacture.

[0153] Needle-like microparticles can be included in the matrix without surface modification. However, surface-modified needle-like microparticles can further improve compatibility and particle dispersibility with the matrix formed from the organic materials described below, thereby readily achieving the effects of the present invention by improving the optical properties of the unpatterned contrast enhancement layer without the agglomeration of needle-like microparticles. 50% or more (e.g., 60% to 100% or 60% to 95%) of the total surface area of ​​the needle-like microparticles can undergo surface modification. Within this range, the compatibility and dispersibility of the needle-like microparticles can be further improved.

[0154] In one embodiment, at least one selected from silane compounds, surfactants, and oils may be used to perform surface modification of the needle-like particles. Preferably, a silane compound containing (meth)acryloyloxy or (meth)acrylate groups is used to perform surface modification of the needle-like particles to ensure good dispersibility and compatibility with the matrix formed by the photochemically curable composition described below.

[0155] Silane compounds containing (meth)acryloxy group or (meth)acrylate group may include 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, and 3-(meth)acryloyloxypropyltriethoxysilane, preferably including at least one selected from 3-(meth)acryloyloxypropyltrimethoxysilane and 3-(meth)acryloyloxypropyltriethoxysilane.

[0156] The refractive index difference between the surface-modified needle-like microparticles and the matrix can be 0.8 or less, preferably 0.5 or less, and more preferably 0.15 to 0.25. Within this range, the needle-like microparticles can further improve contrast and brightness while improving the optical properties of the matrix.

[0157] The refractive index of the surface-modified needle-like microparticles can be from 1.5 to 2.2, preferably from 1.6 to 1.8, and more preferably from 1.65 to 1.7. Within this range, the needle-like microparticles can have a suitable refractive index relative to the matrix, thereby helping to improve contrast and visibility.

[0158] The content of needle-like particles in the unpatterned contrast enhancement layer 320 can be from 1% to 30% by weight, preferably from 4% to 15% by weight. Within this range, the needle-like particles ensure improved contrast and brightness of the liquid crystal display device according to the invention. Conversely, excessive needle-like particles may provide high haze.

[0159] Optical anisotropic materials can be embedded in a matrix.

[0160] The matrix contains an optically anisotropic material embedded therein, which can stably provide improved contrast and visibility.

[0161] The matrix may have a higher or lower refractive index than optically anisotropic materials.

[0162] In one embodiment, the matrix may have a higher refractive index than optically anisotropic materials, and its refractive index may be 1.5 or greater than 1.5, specifically 1.65 to 1.7. Within this range, the matrix can readily achieve the aforementioned refractive index difference.

[0163] In another embodiment, the matrix may have a lower refractive index than optically anisotropic materials, and its refractive index may be 1.2 or greater than 1.2, specifically from 1.4 to 1.60, and more specifically from 1.43 to 1.59. Within this range, the matrix can readily achieve the aforementioned refractive index difference.

[0164] The matrix can be an adhesive layer or bonding layer with bonding or adhesive properties. In this case, the unpatterned contrast enhancement layer can be directly stacked on the polarizer, thereby providing the effect of reducing the thickness of the polarizer. Preferably, the matrix is ​​formed of pressure-sensitive adhesive (PSA). Alternatively, the matrix can be a non-adhesive layer or non-bonding layer without bonding or adhesive properties.

[0165] The matrix may be formed from a composition comprising an ultraviolet (UV) curable resin and / or a thermocurable resin. For example, the matrix may be formed from a composition comprising resins such as (meth)acrylate resins, urethane resins, epoxy resins, silicone resins, urethane (meth)acrylate resins, epoxy (meth)acrylate resins, etc. The composition may further comprise a photoinitiator, a thermosetting agent, and various additives. In one embodiment, the matrix may be formed from a pressure-sensitive adhesive (PSA) to form an adhesive layer, thereby allowing the matrix to be directly stacked on the polarizer.

[0166] Light source side polarizer

[0167] The light source-side polarizer 600 may include a polarizer and a protective layer stacked on at least one surface of the polarizer. The polarizer may be substantially the same as the polarizer described above in the viewer-side polarizer. The protective layer may be substantially the same as the first protective layer described above in the viewer-side polarizer.

[0168] Although Figure 1 It is not shown in the figure, but a reflective prism, diffuser, etc. can be further stacked between the polarizing plate 600 on the light source side and the first optical plate 400 to improve the brightness.

[0169] The invention will now be described in more detail with reference to examples. However, it should be noted that these examples are for illustrative purposes only and should not be construed as limiting the invention in any way.

[0170] Example 1

[0171] (1) Manufacturing of the viewer-side polarizing plate

[0172] A polyethylene terephthalate (PET) film (TA-053, Toyobo Co., Ltd., haze: 0.6%, no antireflective layer) was prepared. A composition for the second resin layer was coated onto the lower surface of the PET film to a predetermined thickness to form a coating, and an optical pattern and flat sections were formed on the coating to form the second resin layer. A composition for the first resin layer was coated onto a surface of the second resin layer having the optical pattern and flat sections, and the composition was cured to form the first resin layer, thereby forming a patterned layer with the specifications listed in Table 1.

[0173] Table 1

[0174] W3 H3 Aspect Ratio θ P cross section Refractive index difference 8.9μm 10.4μm 1.17 81° 13.7μm trapezoid 0.15

[0175] A polarizer (thickness: 17 μm) was prepared by stretching a polyvinyl alcohol film in its machine direction to three times its initial length at 60 °C and dyeing the film with iodine, followed by stretching the dyed film in an aqueous boric acid solution at 40 °C to 2.5 times its initial length in its machine direction.

[0176] A patterned layer is attached to the upper surface of the prepared polarizer, such that the first resin layer and the second resin layer can be stacked sequentially from the polarizer in the order stated therein, and a cyclic olefin polymer (COP) film (ZEON) is bonded to the lower surface of the polarizer, thereby preparing a polarizing plate having a stacking order of PET film / patterned layer (refractive index of the second resin layer: 1.62, refractive index of the first resin layer: 1.47) / polarizer / COP film.

[0177] (2) Fabrication of the light source side polarizing plate

[0178] A polarizer and a polarizing plate with a stacking order of PET film / polarizer / COP film were prepared in accordance with (1).

[0179] (3) Preparation of the first optical plate and the second optical plate

[0180] The composition for the first optical sheet or the composition for the second optical sheet is coated to a predetermined thickness on a surface of a polyethylene terephthalate (PET) film (T910E, thickness: 125 μm, Mitsubishi Co., Ltd.) used as a base layer. A prism pattern is formed on the coating, which is then cured to prepare the first and second optical sheets, each having the specifications in Table 2.

[0181] (4) Fabrication of modules for liquid crystal displays

[0182] The module was manufactured by attaching a viewer-side polarizing plate and a light source-side polarizing plate to the light emitting surface and light incident surface of a liquid crystal panel with a liquid crystal layer (VA liquid crystal), respectively, and then sequentially stacking a first optical sheet and a second optical sheet on the light incident surface of the light source-side polarizing plate.

[0183] Examples 2 to 8

[0184] Apart from the changes made to the modules as listed in Table 2, the modules were manufactured in the same manner as in Example 1.

[0185] Example 9

[0186] The module was fabricated in the same manner as in Example 1, except that a layer containing optically anisotropic particles was formed to replace the patterned layer as a contrast enhancement layer and a viewer-side polarizer with a stacking order of layer / PET film / polarizer / COP film containing optically anisotropic particles was prepared.

[0187] Preparation of layers containing optically anisotropic particles

[0188] Polyethylene terephthalate (PET) film (TA-053, haze: 0.6%, without anti-reflective layer, Toyobo Co., Ltd.) was prepared.

[0189] A compound containing zinc oxide wire (aspect ratio of 90, diameter of 0.7 μm) was mixed with an acrylic pressure-sensitive composition to prepare a composition for a contrast-enhancing layer containing optically anisotropic particles.

[0190] A layer containing optically anisotropic particles (refractive index: 1.48) comprising a matrix (refractive index: 1.47) and zinc oxide lines (refractive index: 2.0) is formed on the lower surface of a PET film by coating the composition in one direction and then drying the composition.

[0191] Comparative Example 1

[0192] The module was manufactured in the same manner as in Example 1, except that a polarizing plate with a stacking order of PET film / polarizer / COP film was used as a viewer-side polarizing plate without a contrast enhancement layer.

[0193] Comparative Example 2 and Comparative Example 3

[0194] Except for changing the angle, the module was manufactured in the same way as in Example 1.

[0195] The properties listed in Table 2 of each of the modules prepared in the examples and comparative examples were evaluated, and the evaluation results are shown in Table 2.

[0196] (1) Left and right viewing angles: The brightness of the liquid crystal display device in white mode (255 gray levels) was measured using an EZCONTRAST X88RC (EZXL-176R-F422A4, ELDIM) in a spherical coordinate system (Φ = 0°, 180°, θ = 0° to 88°). The 50% viewing angle was calculated by summing the angles θ that maintained 50% or more of the front brightness in each case of Φ = 0° (right) and Φ = 180° (left). Viewing angles of 80° or greater were rated as ◎, viewing angles of 70° to less than 80° were rated as ○, and viewing angles of less than 70° were rated as X.

[0197] (2) Black Visibility: Luminance in white mode (255 gray levels) and black mode (0 gray levels) was measured at each of the front (Φ=0°, θ=0°) and side (Φ=0°, θ=60°) positions in a spherical coordinate system using an EZCONTRAST X88RC (EZXL-176R-F422A4, Erdem). Front contrast ratio and side contrast ratio were calculated according to the following equations: Front contrast ratio = (Front luminance in white mode) / (Front luminance in black mode), and side contrast ratio = (Side luminance in white mode) / (Side luminance in black mode). Black visibility was evaluated according to the following equation: Black visibility = Front contrast ratio × Side contrast ratio. (2.0 × 10) 6 or greater than 2.0 × 10 6 The black visibility is rated as ◎, and the value is 1.0×10. 6 To less than 2.0 × 106 The black visibility is rated as ○, and less than 1.0 × 10 6 The black visibility is rated as X.

[0198] Table 2

[0199]

[0200] *In Table 2,

[0201] Angle (A): The angle between the longitudinal direction of the first optical pattern and the vertical direction of the liquid crystal panel.

[0202] Angle (B): The angle between the longitudinal direction of the second optical pattern and the vertical direction of the liquid crystal panel.

[0203] Angle (C): The angle between the longitudinal direction of the engraved optical pattern or the alignment direction of the optically anisotropic particles and the vertical direction of the liquid crystal panel.

[0204] Angle (D): The angle between the longitudinal direction of the first optical pattern and the light absorption axis of the viewer-side polarizer.

[0205] As shown in Table 2, the liquid crystal display device according to the present invention can improve the black visibility and appearance in dark operation mode, and at the same time improve the side viewing angle in bright operation mode, specifically the left and right viewing angle.

[0206] Conversely, the liquid crystal display device of the comparative example, which failed to meet the conditions of the present invention, exhibited poor visibility due to poor left and right viewing angles and insufficient black visibility.

[0207] It should be understood that those skilled in the art can make various modifications, alterations, changes and equivalent examples without departing from the spirit and scope of the invention.

Claims

1. A liquid crystal display device, comprising: LCD panel; Viewer-side polarizing plate, stacked on the light-emitting surface of the liquid crystal panel; as well as The first optical sheet and the second optical sheet are stacked sequentially on the light incident surface of the liquid crystal panel. The viewer-side polarizing plate includes a polarizer and a contrast or viewing angle enhancement layer; The liquid crystal panel has a horizontal direction corresponding to its long side and a vertical direction corresponding to its short side; and The first optical sheet has a plurality of first optical patterns on its light emitting surface, and the angle between the longitudinal direction of the first optical patterns and the vertical direction of the liquid crystal panel is in the range of -10° to +10°. The second optical sheet has a plurality of second optical patterns on its light emitting surface, and the angle between the longitudinal direction of the second optical pattern and the vertical direction of the liquid crystal panel is in the range of 80° to 100°. The contrast or viewing angle enhancement layer includes at least one of a patterned contrast enhancement layer and an unpatterned contrast enhancement layer; The patterned contrast enhancement layer includes a first resin layer and a second resin layer with a different refractive index relative to the first resin layer, and a patterned portion having at least one engraved optical pattern is formed at the interface between the first resin layer and the second resin layer. The engraved optical pattern has a higher aspect ratio than the first optical pattern; Each of the engraved optical patterns has a first surface formed at its top portion and two inclined sides connected to the first surface. The first surface has a generally flat surface and a maximum width of 1 μm to 40 μm.

2. The liquid crystal display device according to claim 1, wherein the first optical sheet is a sheet that collects light in the left-right direction, and the second optical sheet is a sheet that collects light in the up-down direction.

3. The liquid crystal display device according to claim 1, wherein the second optical sheet has a plurality of second optical patterns on its light emitting surface, and the angle between the longitudinal direction of the second optical pattern and the vertical direction of the liquid crystal panel is in the range of 80° to 100°.

4. The liquid crystal display device according to claim 3, wherein the first optical pattern has a vertex angle α of 70° to 120°, and the second optical pattern has a vertex angle β of 70° to 120°.

5. The liquid crystal display device according to claim 3, wherein each of the first optical pattern and the second optical pattern has a strip shape extending in its longitudinal direction.

6. The liquid crystal display device according to claim 1, wherein the angle between the longitudinal direction of the first optical pattern and the light absorption axis of the polarizer is in the range of -10° to 10° or 80° to 100°.

7. The liquid crystal display device according to claim 1, wherein the angle between the longitudinal direction of the engraved optical pattern and the vertical direction of the liquid crystal panel is in the range of -10° to +10°.

8. The liquid crystal display device according to claim 1, wherein the aspect ratio of the engraved optical pattern is 0.3 or greater than 0.

3.

9. The liquid crystal display device according to claim 1, wherein the patterned portion further includes a flat section between adjacent engraved optical patterns.

10. The liquid crystal display device according to claim 1, wherein the refractive index difference between the first resin layer and the second resin layer is 0.2 or less than 0.

2.

11. The liquid crystal display device according to claim 1, wherein the viewer-side polarizing plate does not contain at least one of an anti-reflection layer, a low-reflection layer, and an ultra-low-reflection layer.

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