Liquid crystal display device

Abstract

A liquid crystal display device is disclosed. The liquid crystal display device includes: a liquid crystal panel; and a viewer-side polarizing plate stacked on a light exit surface of the liquid crystal panel, wherein the viewer-side polarizing plate includes a patterned layer including a first resin layer and a second resin layer having different refractive indexes; and a patterned portion is formed at an interface between the first resin layer and the second resin layer, the patterned portion including a plurality of engraved optical patterns and flat sections formed adjacent between the engraved optical patterns, and wherein the liquid crystal display device satisfies the following Equation 1, and the engraved optical patterns have an aspect ratio of 0.3 or greater than 0.3.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2022-0031050, filed on March 11, 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. More specifically, this invention relates to a liquid crystal display device that, in operation, exhibits good diagonal contrast and prevents the formation of moiré patterns and rainbow spots to ensure a good appearance. Background Technology

[0004] In the operation of a liquid crystal display (LCD) device, light emitted from the backlight unit is released through the liquid crystal panel. Therefore, the screen of an LCD device has a good contrast ratio (CR) at its front. However, the screen of an LCD device has a lower contrast ratio at the sides than at the front. Therefore, it is recommended to coat a film formed by patterned portions with a predetermined pattern onto the viewer-side polarizing plate to improve contrast and viewing angle.

[0005] Patterned portions can improve contrast and viewing angle at the sides. In liquid crystal display devices, the liquid crystal panel includes a plurality of fine unit pixels, which include red, green, and blue pixels in a color filter. However, the inventors of this invention have confirmed that such pixels, together with the patterned portions, can produce moiré patterns and rainbow spots after operation of the display device.

[0006] The background technology of the present invention is disclosed in Korean Patent Publication No. 2018-0047569 and others. Summary of the Invention

[0007] The present invention provides a liquid crystal display device that has good diagonal contrast in operation and prevents the generation of moiré patterns and rainbow spots to ensure a good appearance.

[0008] One aspect of the present invention relates to a liquid crystal display device.

[0009] 1. A liquid crystal display device includes: a liquid crystal panel; and a viewer-side polarizing plate stacked on the light-emitting surface of the liquid crystal panel, wherein the viewer-side polarizing plate includes a patterned layer comprising a first resin layer and a second resin layer having different refractive indices; and a patterned portion is formed at the interface between the first resin layer and the second resin layer, the patterned portion comprising a plurality of engraved optical patterns and flat segments formed between adjacent engraved optical patterns; and wherein the liquid crystal display device satisfies Equation 1 below, and the engraved optical patterns have an aspect ratio of 0.3 or greater than 0.3:

[0010] [Equation 1]

[0011] 7≤P2 / P1≤85

[0012] Where P1 is the spacing of the patterned portion (unit: micrometers), and

[0013] P2 is the width (in micrometers) of a pixel in the liquid crystal panel in the same direction as the maximum width of the engraved optical pattern.

[0014] 2. In step 1, the engraved optical pattern can be arranged in the same direction as the short side of the liquid crystal panel.

[0015] 3. In 2, in Equation 1, P2 can be the sum of the width of a unit pixel in the vertical direction of the unit pixel and the width of a black matrix in the vertical direction.

[0016] 4. In steps 1 to 3, the engraved optical pattern can be arranged in the same direction as the long side of the liquid crystal panel.

[0017] 5. In 4, in Equation 1, P2 can be the sum of the widths of the unit pixels of a pixel in the horizontal direction of each unit pixel and the sum of the widths of the three black matrices in their horizontal directions.

[0018] 6. In 1 to 5, a pixel may be a pixel assembly, which includes three unit pixels consisting of a red unit pixel, a green unit pixel, and a blue unit pixel, and a black matrix that separates the corresponding unit pixel from the other unit pixels.

[0019] 7. In 1 to 6, the liquid crystal panel may include a plurality of pixels, the plurality of pixels being arranged on the long side direction and the short side direction of the liquid crystal panel respectively, such that red unit pixels, green unit pixels and blue unit pixels are repeatedly arranged on the long side direction in the stated order, and red unit pixels, green unit pixels or blue unit pixels are individually arranged on the short side direction.

[0020] 8. In 1 to 7, in Equation 1, P1 can be in the range of 7 micrometers to 50 micrometers, and P2 can be in the range of 50 micrometers to 1,000 micrometers.

[0021] 9. In 1 to 8, the engraved optical pattern can be arranged in the same direction as the light absorption axis of the polarizer.

[0022] 10. In 1 through 9, the engraved optical pattern may have an N-sided cross-section (N being an integer from 3 to 10) or a cross-section with curved side surfaces.

[0023] 11. In 1 to 10, the maximum width of the engraved optical pattern can be in the range of 30% to less than 100% of the spacing P1 of the patterned portion.

[0024] 12. In 1 to 11, the patterned portions may have the same P1, and the engraved optical patterns may have the same maximum width.

[0025] The present invention provides a liquid crystal display device that has good diagonal contrast in operation and prevents the generation of moiré patterns and rainbow spots to ensure a good appearance. Attached Figure Description

[0026] Figure 1 This is a partial perspective view of a liquid crystal display device according to an embodiment of the present invention.

[0027] Figure 2 This is a magnified plan view of a portion of the color filter.

[0028] Figure 3 A conceptual diagram of P2 in this invention is shown.

[0029] Figure 4 A conceptual diagram of P2 in this invention is shown.

[0030] Figure 5 This is a partial cross-sectional view of the polarizing plate on the viewer's side.

[0031] Figure 6 A cross-sectional view for engraving optical patterns.

[0032] Explanation of reference numerals in the attached figures

[0033] 1: Red unit pixel;

[0034] 2: Green unit pixels;

[0035] 3: Blue unit pixels;

[0036] 4: Black Matrix;

[0037] 100: LCD panel;

[0038] 200: Viewer-side polarizing plate;

[0039] 210: Polarizer;

[0040] 220: Patterned layer;

[0041] 221: First resin layer;

[0042] 222: Second resin layer;

[0043] 223: Engraving optical patterns;

[0044] 224: Flat section;

[0045] 225: First surface;

[0046] 226: First side surface;

[0047] 227: Second side surface;

[0048] 228: Fill pattern;

[0049] 230: Protective layer;

[0050] 300: Light source side polarizer;

[0051] A, C: Horizontal width;

[0052] B, D: Vertical width;

[0053] H: Maximum height;

[0054] L, W: Maximum width;

[0055] θ: Base angle. Detailed Implementation

[0056] In the following description, embodiments of the invention will be detailed 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 embodied in different ways and is not limited to the following embodiments.

[0057] In the accompanying drawings, components irrelevant to the description are omitted for clarity of the invention, and the same components will be indicated by the same reference numerals throughout the specification.

[0058] In this document, spatial relative terms such as “upper” and “lower” are defined with reference to the accompanying drawings. Therefore, it will be understood that “upper surface” and “lower surface” are used interchangeably, and when an element is referred to as being placed “on” another element, the element may be placed directly on the other element, or there may be intervening elements present. When an element is referred to as being placed “directly” on another element, there are no intervening elements present.

[0059] In this paper, "in-plane delay (Re)" is the value measured at a wavelength of 550 nm, as calculated according to Equation A:

[0060] Re = (nx - ny) × d, --- (A)

[0061] Where nx and ny are the refractive indices of the protective layer in the slow axis and fast axis directions at a wavelength of 550 nm, respectively, and d is the thickness of the protective layer (in nanometers).

[0062] In this article, "(meth)acryloyl" refers to acryloyl and / or methacryloyl.

[0063] As used in this article to represent a specific numerical range, "X to Y" means "X ≤ and ≤ Y".

[0064] The liquid crystal display device according to the present invention comprises: a liquid crystal panel; and a viewer-side polarizing plate stacked on the light-emitting surface of the liquid crystal panel, wherein the viewer-side polarizing plate comprises a patterned layer, the patterned layer comprising a first resin layer and a second resin layer having different refractive indices; and a patterned portion is formed at the interface between the first resin layer and the second resin layer, the patterned portion comprising a plurality of engraved optical patterns and flat segments formed between adjacent engraved optical patterns, and wherein the liquid crystal display device satisfies Equation 1 below, and the engraved optical patterns have an aspect ratio of 0.3 or greater than 0.3.

[0065] [Equation 1]

[0066] 7≤P2 / P1≤85

[0067] Where P1 is the spacing of the patterned portion (unit: micrometers), and

[0068] P2 is the width (in micrometers) of a pixel in the liquid crystal panel in the same direction as the maximum width of the engraved optical pattern.

[0069] According to the present invention, in a liquid crystal display device comprising a viewer-side polarizing plate having patterned portions, among several elements of the patterned portions and several elements of the pixel assembly in the liquid crystal panel, the ratio of the width of a pixel in a specific direction in the liquid crystal panel to the spacing of the patterned portions is adjusted to a specific ratio, thereby ensuring good diagonal contrast and preventing the generation of moiré patterns and rainbow spots caused by the lamination of the patterned portions and pixels, thus ensuring a good appearance. When only the width of the engraved optical pattern in the patterned portions is adjusted, problems may arise with poor patterning processing or formation, or the target diagonal contrast may not be achieved. When only the width of the pixels is adjusted, problems may arise with insufficient resolution or high power consumption due to low aperture ratio.

[0070] If P2 / P1 is less than 7, moiré patterns may be observed. If P2 / P1 exceeds 85, rainbow spots may be observed, or it may be difficult to form a patterned layer in the polarizer on the viewer's side, thus making it difficult to achieve the desired side contrast. For example, the P2 / P1 value of a liquid crystal display device can be 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43. The values ​​are: 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, or 85. Preferably, the P2 / P1 value of the liquid crystal display device is 8 to 30, more preferably 10 to 30.

[0071] In the following text, reference will be made to Figures 1 to 6 A liquid crystal display device according to the present invention is described.

[0072] The liquid crystal display device includes a liquid crystal panel 100, a viewer-side polarizing plate 200, and a light source-side polarizing plate 300.

[0073] LCD panel

[0074] The liquid crystal panel 100 includes a light-incident surface and a light-exit surface facing each other. The light-incident surface refers to the surface from which a light source is emitted from below the lower surface of the light-source side polarizer 300. Figure 1 The light emitted (internal light) from the polarizer 200 (not shown) passes through the plane through which it enters the liquid crystal panel. The light emitting surface refers to the plane through which the light that has entered the liquid crystal panel passes, emitted towards the viewer's side.

[0075] In one embodiment, the liquid crystal panel 100 has a rectangular shape consisting of a long side corresponding to the horizontal direction and a short side corresponding to the vertical direction.

[0076] The liquid crystal panel 100 may include an upper transparent substrate, a lower transparent substrate, and a liquid crystal layer inserted between the upper transparent substrate and the lower transparent substrate. Figure 1(Not shown in the image). For example, the liquid crystal may include at least one selected from the following: 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.

[0077] The liquid crystal panel 100 may include a color filter and a thin-film transistor (TFT) filter formed on one of an upper transparent substrate and a lower transparent substrate and facing each other. The color filter may have multiple pixels, and each of the multiple pixels includes multiple unit pixels to improve light contrast. In one embodiment, the color filter may be disposed on the upper surface of the liquid crystal layer in the liquid crystal panel.

[0078] In a color filter, multiple pixels are arranged along both the long and short sides of the liquid crystal panel. (Reference) Figure 2 The pixels will be described in detail.

[0079] In this article, references Figure 2 A "pixel" is defined as a pixel assembly comprising three unit pixels: a red unit pixel 1, a green unit pixel 2, and a blue unit pixel 3, and a black matrix 4 separating each unit pixel from the others. Each pixel may have a square or rectangular shape. Within a pixel, the unit pixels are arranged in one direction and have the same size and shape.

[0080] like Figure 2 As shown, in the color filter, multiple pixels can be arranged on the long side and short side of the liquid crystal panel respectively, such that red unit pixel 1, green unit pixel 2 and blue unit pixel 3 are repeatedly arranged on the long side in the stated order, and red unit pixel 1, green unit pixel 2 or blue unit pixel 3 are arranged individually on the short side.

[0081] When the direction of the maximum width of the etched optical pattern in the patterned portion of the polarizing plate on the viewer's side is as follows: Figure 3When the liquid crystal panel shown is in the short side direction, P2 in Equation 1 is defined as the sum (B+D) of the width of any unit pixel in the vertical direction of the unit pixel and the width of a black matrix in the vertical direction. In one embodiment, P2 can be in the range of 50 micrometers to 1,000 micrometers, for example 50 micrometers, 100 micrometers, 150 micrometers, 200 micrometers, 250 micrometers, 300 micrometers, 350 micrometers, 400 micrometers, 450 micrometers, 500 micrometers, 550 micrometers, 600 micrometers, 650 micrometers, 700 micrometers, 750 micrometers, 800 micrometers, 850 micrometers, 900 micrometers, 950 micrometers or 1,000 micrometers, specifically 150 micrometers to 950 micrometers, and more specifically 150 micrometers to 500 micrometers. Within this range, the liquid crystal display device can easily achieve P2 / P1 according to Equation 1 of the present invention.

[0082] When the direction of the maximum width of the etched optical pattern in the patterned portion of the polarizing plate on the viewer's side is as follows: Figure 4 When the long side of the liquid crystal panel shown is in the orientation, P2 is defined as the sum of the width of the three unit pixels of a pixel in the horizontal direction and the width of the three black matrices in the horizontal direction (3A+3C). In one embodiment, P2 can be in the range of 50 micrometers to 1000 micrometers, for example 50 micrometers, 100 micrometers, 150 micrometers, 200 micrometers, 250 micrometers, 300 micrometers, 350 micrometers, 400 micrometers, 450 micrometers, 500 micrometers, 550 micrometers, 600 micrometers, 650 micrometers, 700 micrometers, 750 micrometers, 800 micrometers, 850 micrometers, 900 micrometers, 950 micrometers or 1000 micrometers, specifically 150 micrometers to 950 micrometers, 150 micrometers to 500 micrometers. Within this range, the liquid crystal display device can easily achieve P2 / P1 according to Equation 1 of the present invention.

[0083] Within a pixel, the horizontal width A of each unit pixel can range from 10 micrometers to 300 micrometers, for example, 10 micrometers, 20 micrometers, 30 micrometers, 40 micrometers, 50 micrometers, 60 micrometers, 70 micrometers, 80 micrometers, 90 micrometers, 100 micrometers, 110 micrometers, 120 micrometers, 130 micrometers, 140 micrometers, 150 micrometers, 160 micrometers, 170 micrometers, 180 micrometers, 190 micrometers, 200 micrometers, 210 micrometers, 220 micrometers, 230 micrometers, 240 micrometers, 250 micrometers, 260 micrometers, 270 micrometers, 280 micrometers, 290 micrometers, or 300 micrometers. Specifically, it is between 20 micrometers and 200 micrometers. Furthermore, the vertical width B is greater than the horizontal width A and falls within the range of 50 micrometers to 900 micrometers, for example, 50 micrometers, 100 micrometers... Meters, 150 micrometers, 200 micrometers, 250 micrometers, 300 micrometers, 350 micrometers, 400 micrometers, 450 micrometers, 500 micrometers, 550 micrometers, 600 micrometers, 650 micrometers, 700 micrometers, 750 micrometers, 800 micrometers, 850 micrometers, or 900 micrometers, specifically from 80 micrometers to 500 micrometers; and the horizontal width C or vertical width D of each element in the black matrix can be from 2 micrometers to 100 micrometers, for example, 2 micrometers, 5 micrometers, 10 micrometers, 15 micrometers, 20 micrometers, 25 micrometers, 30 micrometers, 35 micrometers, 40 micrometers, 45 micrometers, 50 micrometers, 55 micrometers, 60 micrometers, 65 micrometers, 70 micrometers, 75 micrometers, 80 micrometers, 85 micrometers, 90 micrometers, 95 micrometers, or 100 micrometers, specifically from 4 micrometers to 80 micrometers.

[0084] Preferably, the liquid crystal panels 100 have the same P2 value.

[0085] Viewer-side polarizer

[0086] The viewer-side polarizer 200 can be stacked on the light-emitting surface of the liquid crystal panel 100 to release the light received from the liquid crystal panel, while significantly improving the contrast at the front and diagonal directions.

[0087] The viewer-side polarizer 200 includes a polarizer 210, a patterned layer 220, and a protective layer 230.

[0088] The patterned layer 220 may be stacked on the light emitting surface or the light incident surface of the polarizer 210. Preferably, the patterned layer 220 is stacked on the light emitting surface of the polarizer. Here, the "light emitting surface" refers to the surface from which light is emitted from the light source (…). Figure 1 The plane through which the light (internal light) emitted from the liquid crystal panel 100 passes. Additionally, the "light incident surface" is the plane through which the light emitted from the liquid crystal panel 100 enters the polarizer.

[0089] The patterned layer 220 has a first resin layer 221 and a second resin layer 222 with different refractive indices. In the polarizer, the first resin layer 221 and the second resin layer 222 are stacked sequentially on the polarizer 210.

[0090] The 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.

[0091] P1 is defined as the sum of the maximum width W of an engraved optical pattern and the maximum width L of the flat segment between adjacent engraved optical patterns, W+L. P1 can be in the range of 7 micrometers to 50 micrometers, for example, 7 micrometers, 8 micrometers, 9 micrometers, 10 micrometers, 11 micrometers, 12 micrometers, 13 micrometers, 14 micrometers, 15 micrometers, 16 micrometers, 17 micrometers, 18 micrometers, 19 micrometers, 20 micrometers, 21 micrometers, 22 micrometers, 23 micrometers, 24 micrometers, 25 micrometers, 26 micrometers, 27 micrometers, 28 micrometers, 29 micrometers, 30 micrometers, 31 micrometers, 32 micrometers, 33 micrometers, 34 micrometers, 35 micrometers, 36 micrometers, 37 micrometers, 38 micrometers, 39 micrometers, 40 micrometers, 41 micrometers, 42 micrometers, 43 micrometers, 44 micrometers, 45 micrometers, 46 micrometers, 47 micrometers, 48 ​​micrometers, 49 micrometers, or 50 micrometers, specifically 11 micrometers to 34 micrometers. Within this range, liquid crystal display devices can easily achieve P2 / P1 according to Equation 1 of the present invention.

[0092] Patterned parts can have the same P1 value.

[0093] Each of the engraved optical patterns 223 may have a strip shape, and multiple engraved optical patterns 223 may be arranged in one direction relative to the liquid crystal panel 100.

[0094] In one embodiment, the engraved optical pattern can be arranged in the same direction as the short side of the liquid crystal panel, such as... Figure 3 As shown in the diagram. Here, the direction of the maximum width of the engraved optical pattern can be the same as the vertical direction of each unit pixel in a pixel.

[0095] In another embodiment, the engraved optical pattern can be arranged in the same direction as the long side of the liquid crystal panel, such as... Figure 4 As shown in the diagram. Here, the direction of the maximum width of the engraved optical pattern can be the same as the lateral direction of each unit pixel in a pixel.

[0096] The patterned portion can satisfy Equation 2 below, and the engraved optical pattern 223 can have a base angle θ of 75° to 90°. Within this range, the patterned portion can improve the diagonal contrast ratio by suppressing light leakage in the diagonal direction while minimizing the loss of front brightness, and can reduce the difference between front contrast and diagonal contrast.

[0097] [Equation 2]

[0098] 1 <P1 / W≤10

[0099] Where P1 is the spacing of the patterned portion (unit: micrometers), and

[0100] W represents the maximum width of the engraved optical pattern (unit: micrometers).

[0101] The base angle θ refers to the angle defined between the portion of the side surface of the engraved optical pattern 223 directly connected to the maximum width W of the engraved optical pattern 223 and the maximum width W of the engraved optical pattern 223. Preferably, the base angle θ is in the range of 80° to 90°, and P1 / W in Equation 2 is in the range of 1.2 to 8.

[0102] The engraved optical pattern 223 may be an optical pattern protruding from the first resin layer 221 toward the second resin layer 222.

[0103] The engraved optical pattern 223 has an aspect ratio (the ratio of maximum height H to maximum width W) of 0.3 or greater. Within this range, the engraved optical pattern 223 can help improve diagonal contrast. For example, the aspect ratio of the engraved optical pattern 223 can be 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2, preferably 0.6 or greater, more preferably 0.6 to 3, and even more preferably 1.1 to 2.

[0104] The maximum width W of the engraved optical pattern 223 can be in the range of 30% to less than 100% of the spacing P1 of the patterned portion, for example 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99%, specifically 35% to 70%, and more specifically 50% to 70%. Within this range, the liquid crystal display device can suppress the visualization of moiré patterns and rainbow spots.

[0105] The maximum width W of the engraved optical pattern 223 can be from 3 micrometers to 50 micrometers, for example, 3 micrometers, 4 micrometers, 5 micrometers, 6 micrometers, 7 micrometers, 8 micrometers, 9 micrometers, 10 micrometers, 11 micrometers, 12 micrometers, 13 micrometers, 14 micrometers, 15 micrometers, 16 micrometers, 17 micrometers, 18 micrometers, 19 micrometers, 20 micrometers, 21 micrometers, 22 micrometers, 23 micrometers, 24 micrometers, 25 micrometers, 26 micrometers, 27 micrometers, 28 micrometers, 29 micrometers, 30 micrometers, 31 micrometers, 32 micrometers, 33 micrometers, 34 micrometers, 35 micrometers, 36 micrometers, 37 micrometers, 38 micrometers, 39 micrometers, 40 micrometers, 41 micrometers, 42 micrometers, 43 micrometers, 44 micrometers, 45 micrometers, 46 micrometers, 47 micrometers, 48 ​​micrometers, 49 micrometers, or 50 micrometers, preferably from 5 micrometers to 30 micrometers, more preferably from 5 micrometers to 50 micrometers. The aspect ratio is 20 micrometers, and the maximum height H is 3 to 50 micrometers, for example, 3 micrometers, 4 micrometers, 5 micrometers, 6 micrometers, 7 micrometers, 8 micrometers, 9 micrometers, 10 micrometers, 11 micrometers, 12 micrometers, 13 micrometers, 14 micrometers, 15 micrometers, 16 micrometers, 17 micrometers, 18 micrometers, 19 micrometers, 20 micrometers, 21 micrometers, 22 micrometers, 23 micrometers, 24 micrometers, 25 micrometers, 26 micrometers, 27 micrometers, 28 micrometers, 29 micrometers, 30 micrometers, 31 micrometers, 32 micrometers, 33 micrometers, 34 micrometers, 35 micrometers, 36 micrometers, 37 micrometers, 38 micrometers, 39 micrometers, 40 micrometers, 41 micrometers, 42 micrometers, 43 micrometers, 44 micrometers, 45 micrometers, 46 micrometers, 47 micrometers, 48 ​​micrometers, 49 micrometers, or 50 micrometers, preferably 5 micrometers to 30 micrometers, more preferably 5 micrometers to 20 micrometers. Within this range, the liquid crystal display device can easily achieve the aspect ratio of the present invention while improving the diagonal contrast.

[0106] In one embodiment, the engraved optical pattern may have the same maximum width W between adjacent engraved optical patterns and the same maximum height H between adjacent engraved optical patterns. In another embodiment, the engraved optical pattern may have the same maximum height H in its longitudinal direction.

[0107] The engraved optical pattern 223 may have a first surface 225 formed at its top portion and two side surfaces (first side surface 226 and second side surface 227) connected to the first surface.

[0108] A first surface 225 is formed at the top portion of the etched optical pattern 223 and emits light received from the etched optical pattern 223, thereby improving the brightness of the liquid crystal display device. The first surface 225 may be a generally flat surface. The first surface 225 may have a maximum width of 3 micrometers to 45 micrometers, preferably 5 micrometers to 30 micrometers. Within this range, the liquid crystal display device can easily achieve the high aspect ratio of the present invention while improving diagonal contrast.

[0109] Each of the first side surface 226 and the second side surface 227 may be composed of one or more flat surfaces (e.g., 1 to 3 flat surfaces).

[0110] In one embodiment, each of the first side surface 226 and the second side surface 227 may be composed of a flat surface, such as Figure 5 As shown in the figure.

[0111] In another embodiment, each of the first side surface and the second side surface may consist of two or more flat surfaces, such as Figure 6 As shown, each of the flat surfaces may have a different base angle θ. Here, base angle θ refers to the angle defined between the portion of the side surface of the engraved optical pattern directly connected to the maximum width W of the engraved optical pattern and the maximum width W of the engraved optical pattern. Each of the side surfaces may be a convex polygonal surface protruding from the first resin layer to the second resin layer. Figure 6 (A) or a recessed polygonal surface protruding from the second resin layer to the first resin layer. Figure 6 (B)). The base angle θ can be in the range of 60° to 90° (e.g., 75° to 90°). Within this range, the liquid crystal display device can easily achieve the effects of the present invention.

[0112] For example, engraved optical patterns can 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.

[0113] Each of the side surfaces may consist of one or more curved surfaces (e.g., 1 to 3 curved surfaces).

[0114] In one embodiment, each of the side surfaces may be formed by a single curved surface. In another embodiment, each of the side surfaces may be formed by two or more curved surfaces, wherein the curved surfaces may have different base angles θ relative to the maximum width of the engraved optical pattern. Here, the base angle θ refers to the angle defined between the tangent of the corresponding curved surface at half the maximum height of the engraved optical pattern and the maximum width W of the engraved optical pattern.

[0115] Here, each of the side surfaces can be a convex curved surface protruding from the first resin layer to the second resin layer, or a concave curved surface protruding from the second resin layer to the first resin layer. The bottom angle can be in the range of 60° to 90° (e.g., 75° to 90°). Within this range, the liquid crystal display device can easily achieve the effects of the present invention.

[0116] Adjacent engraved optical patterns 223 can be spaced apart from each other by flat sections 224. Flat sections 224 allow vertically received light from the polarizer to pass through them, thereby improving brightness. The maximum width L of the flat sections 224 can be greater than 0 micrometers to 40 micrometers, for example, 1 micrometer, 2 micrometers, 3 micrometers, 4 micrometers, 5 micrometers, 6 micrometers, 7 micrometers, 8 micrometers, 9 micrometers, 10 micrometers, 11 micrometers, 12 micrometers, 13 micrometers, 14 micrometers, 15 micrometers, 16 micrometers, 17 micrometers, 18 micrometers, 19 micrometers, 20 micrometers, 21 micrometers, 22 micrometers, 23 micrometers, 24 micrometers, 25 micrometers, 26 micrometers, 27 micrometers, 28 micrometers, 29 micrometers, 30 micrometers, 31 micrometers, 32 micrometers, 33 micrometers, 34 micrometers, 35 micrometers, 36 micrometers, 37 micrometers, 38 micrometers, 39 micrometers, or 40 micrometers, specifically 3 micrometers to 25 micrometers, and more specifically 4 micrometers to 20 micrometers. Within this range, engraving optical patterns can improve diagonal contrast while reducing the difference between frontal contrast and diagonal contrast.

[0117] The first resin layer 221 may be formed with at least a portion of a filling pattern 228 of the filled engraved optical pattern 223.

[0118] The second resin layer 222 may have a higher or lower refractive index than the first resin layer 221. Preferably, the second resin layer 222 has a higher refractive index than the first resin layer 221 to ensure further improved visibility.

[0119] 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 patterning layer can help improve diagonal contrast. In one embodiment, the refractive index of the first resin layer 221 can be less than 1.53, for example, 1.30 to less than 1.53, and the refractive index of the second resin layer 222 can be 1.53 or greater than 1.53, for example, 1.53 to 1.70.

[0120] The polarizer 210 may have an in-plane light absorption axis and a light transmission axis, and may emit polarized light toward the patterning layer by means of the polarization of light received from the liquid crystal panel. The light absorption axis corresponds to the longitudinal direction (machine direction, MD) of the polarizer, and the light transmission axis corresponds to the transverse direction (transverse direction, TD) of the polarizer.

[0121] In one embodiment, the engraved optical pattern may be arranged in the same direction as the light absorption axis of the polarizer. For example, assuming the light absorption axis of the polarizer is aligned in the 0° direction, the longitudinal direction of the engraved optical pattern may be tilted relative to the light absorption axis of the polarizer at an angle of -5° to 5°, -1° to 1°, or 0°.

[0122] Polarizer 210 may comprise a polyvinyl alcohol polarizer formed by uniaxial stretching of a polyvinyl alcohol film or a polyene 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.

[0123] The polarizer 210 can have a thickness ranging from 5 micrometers to 40 micrometers. Within this range, polarizers can be used in optical displays.

[0124] The protective layer 230 is a light-transmitting layer that can transmit and diffuse light that passes through the patterned layer.

[0125] The 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 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 effect of diffused light that has passed through the second resin layer and the first resin layer. In another embodiment, the protective layer may be an isotropic film having 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 protective layer can improve image quality by compensating for the field of view. Here, an isotropic film means a film in which all nx, ny, and nz 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 between them. Preferably, the in-plane retardation (Re) of the 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.

[0126] The protective layer 230 may have a thickness of 30 micrometers to 120 micrometers (specifically 20 micrometers to 80 micrometers). Within this range, the protective layer can be applied to optical displays. The protective layer 230 may have a transmittance of 80% or greater (specifically 85% to 95%) in the visible spectrum. The protective layer 230 may comprise a film prepared by uniaxial or biaxial stretching of an optically transparent resin. Specifically, the resin may comprise at least one selected from the following: polyesters, including polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, etc.; acrylic resins; 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; polyarylate; and polyimide. Preferably, the protective layer comprises a film formed from a polyester resin. The protective layer may comprise a film manufactured by modifying the above resins. Modification may include copolymerization, branching, crosslinking, or end-molecule modification.

[0127] although Figure 1 Not shown, but a functional coating may be further formed on at least one surface of the protective layer 230 to provide additional functionality. The functional coating may be a base coat, a hard coat, or an anti-fingerprint layer, but is not limited thereto.

[0128] Light source side polarizer

[0129] The light source-side polarizer 300 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 of the viewer-side polarizer. The protective layer may be substantially the same as the protective layer of the viewer-side polarizer.

[0130] although Figure 1 Although not shown in the figure, reflective prisms, diffusers, etc., can be further placed between the light source-side polarizing plate 300 and the liquid crystal panel 100 to improve brightness.

[0131] The invention will now be described in more detail with reference to examples. However, it should be noted that these examples are provided by way of illustration only and should not be construed as limiting the invention in any way.

[0132] Example 1

[0133] (1) Preparation of viewer-side polarizing plate

[0134] A polyethylene terephthalate (PET) film (TA-053 from Toyobo) was prepared. A second resin layer composition (SSC-6030 from Shin-A T&C, Korea) 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. The coating was then cured to form the second resin layer. A first resin layer composition (SSC-4560 from Shin-A T&C, Korea) was coated onto one surface of the second resin layer having the optical pattern and flat sections, and cured to form the first resin layer, thereby forming a patterned layer having the specifications listed in Table 1.

[0135] A polarizer (thickness: 13 micrometers) was prepared by stretching a polyvinyl alcohol film to three times its initial length at 60°C, dyeing the film with iodine, and then stretching the dyed film to 2.5 times its initial length in an aqueous boric acid solution at 40°C.

[0136] A patterned layer is attached to the upper surface of the polarizer, such that the first resin layer and the second resin layer can be stacked sequentially from the polarizer in the stated order, and a cyclic olefin polymer (COP) film (ZEON) is bonded to the lower surface of the polarizer, thereby preparing a polarizing plate with the 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.

[0137] (2) Fabrication of the light source side polarizing plate

[0138] Refer to (1) to prepare polarizers and polarizing plates with a stacking order of PET film / polarizer / COP film in sequence.

[0139] (3) Module for preparing liquid crystal display devices

[0140] The module is 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 having a liquid crystal layer (VA liquid crystal). Here, the arrangement direction of the engraved optical pattern, the arrangement direction of the pixel assembly in the viewer-side polarizing plate, and the spacing P1 of the engraved optical pattern and the spacing P2 of the pixel assembly are adjusted as shown in Table 1.

[0141] Examples 2 to 5

[0142] Except for the changes to P1, P2, P2 / P1 and the arrangement direction as listed in Table 1, the modules are manufactured in the same manner as in Example 1.

[0143] Comparative Examples 1 to 3

[0144] Except for the changes to P1, P2, P2 / P1 and the arrangement direction as listed in Table 1, the modules are manufactured in the same manner as in Example 1.

[0145] Comparative Example 4

[0146] Except for the changes to the engraved optical patterns and pixel assemblies listed in Table 1, the module is manufactured in the same manner as in Example 1.

[0147] The evaluation results for each of the modules prepared in the examples and comparative examples listed in Table 1 are shown in Table 1.

[0148] (1) Moiré patterns: The presence of moiré patterns is assessed visually. The absence of moiré patterns is rated as 0, and the presence of moiré patterns is rated as level 1 to 4. Level 0 or 1 is rated as ◎, level 2 is rated as ○, and level 3 or 4 is rated as X.

[0149] (2) Rainbow spots: The presence of rainbow spots is assessed visually. The absence of rainbow spots is rated as 0, and the presence of rainbow spots is rated as grade 1 to 5. Grade 0 or 1 is rated as ◎, grade 2 as ○, grade 3 as △, and grade 4 or 5 as X.

[0150] (3) Relative diagonal contrast ratio: The brightness of the liquid crystal display device was measured in a spherical coordinate system with diagonal angles (Φ = 45°, θ = 60°) in both white and black modes using an EZCONTRAST X88RC (EZXL-176R-F422A4, ELDIM). The diagonal contrast ratio was calculated according to the following equation: (diagonal brightness in white mode) / (diagonal brightness in black mode). Assuming that the liquid crystal display device without patterned portions has a diagonal contrast ratio of 100%, a diagonal contrast ratio of 120% or greater was rated as ○, and a diagonal contrast ratio less than 120% was rated as X.

[0151] Table 1

[0152]

[0153] As shown in Table 1, the liquid crystal display device according to the present invention does not produce moiré patterns or rainbow spots during operation, thereby providing a good appearance. Furthermore, the liquid crystal display device according to the present invention has good diagonal contrast.

[0154] Conversely, the liquid crystal display devices of Comparative Example 1 and Comparative Example 2, which have a P2 / P1 value of less than 7 in Equation 1, exhibit moiré patterns. The liquid crystal display device of Comparative Example 3, which has a P2 / P1 value of greater than 85 in Equation 1, exhibits a red spot problem. The liquid crystal display device of Comparative Example 4, manufactured by adjusting the P2 / P1 in Equation 1 and the maximum height H of the patterned portion, shows that the diagonal contrast is not sufficiently improved.

[0155] It should be understood that those skilled in the art can make various modifications, variations, alterations, and equivalent embodiments without departing from the spirit and scope of the invention.

Claims

1. A liquid crystal display device, comprising a liquid crystal panel and a viewer-side polarizing plate stacked on the light-emitting surface of the liquid crystal panel. The viewer-side polarizing plate includes a patterned layer comprising a first resin layer and a second resin layer with different refractive indices; and a patterned portion is formed at the interface between the first resin layer and the second resin layer, the patterned portion comprising a plurality of etched optical patterns and flat sections formed between adjacent etched optical patterns. The liquid crystal display device satisfies Equation 1 below, and the engraved optical pattern has an aspect ratio of 0.3 or greater than 0.3: [Equation 1] 7 ≤ P2 / P1 ≤ 85 Where P1 is the sum of the maximum width of an engraved optical pattern and the maximum width of the flat segment between adjacent engraved optical patterns, and P2 is the width of a pixel of the liquid crystal panel in the same direction as the maximum width of the engraved optical pattern, where the units of P1 and P2 are micrometers.

2. The liquid crystal display device according to claim 1, wherein the direction of the maximum width of the engraved optical pattern is the same as the longitudinal direction of each unit pixel in a pixel.

3. The liquid crystal display device according to claim 2, wherein P2 is the sum of the width of a unit pixel of a pixel in the vertical direction of the unit pixel and the width of a black matrix in the vertical direction.

4. The liquid crystal display device according to claim 1, wherein the direction of the maximum width of the engraved optical pattern is the same as the lateral direction of each unit pixel in a pixel.

5. The liquid crystal display device according to claim 4, wherein P2 is the sum of the width of the three unit pixels of a pixel in the horizontal direction of each unit pixel and the width of the three black matrices in the horizontal direction.

6. The liquid crystal display device according to claim 1, wherein the pixel is a pixel assembly, the pixel assembly comprising three unit pixels composed of red unit pixels, green unit pixels and blue unit pixels, and a black matrix that separates the corresponding unit pixel from the other unit pixels.

7. The liquid crystal display device according to claim 1, wherein the liquid crystal panel includes a plurality of pixels, and the plurality of pixels are respectively arranged in the long side direction and the short side direction of the liquid crystal panel, such that red unit pixels, green unit pixels and blue unit pixels are repeatedly arranged in the long side direction in the stated order, and red unit pixels, green unit pixels or blue unit pixels are individually arranged in the short side direction.

8. The liquid crystal display device according to claim 1, wherein in Equation 1, P1 is in the range of 7 micrometers to 50 micrometers, and P2 is in the range of 50 micrometers to 1000 micrometers.

9. The liquid crystal display device according to claim 1, wherein the longitudinal direction of the engraved optical pattern is arranged in the same direction as the light absorption axis of the polarizer.

10. The liquid crystal display device according to claim 1, wherein the engraved optical pattern has an N-sided cross-section or a cross-section having curved side surfaces, wherein N is an integer from 3 to 10.

11. The liquid crystal display device according to claim 1, wherein the maximum width of the engraved optical pattern is in the range of 30% to less than 100% of the spacing of the patterned portion.

12. The liquid crystal display device according to claim 1, wherein the patterned portions have the same P1, and the engraved optical patterns have the same maximum width.

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