KR102498950B1 - Polarizing plate and liquid crystal display apparatus comprising the same - Google Patents

Abstract

polarizer; and a pattern layer formed on the light exit surface of the polarizer, wherein the pattern layer includes a first resin layer and a second resin layer sequentially formed from the polarizer, and the first resin layer and the second resin layer are A pattern part is formed at the interface, the pattern part is composed of two or more pattern groups that are repeatedly arranged, the pattern group includes two or more engraved optical patterns, and two or more of the engraved optical patterns are selected from the pattern group. At least one aspect ratio and base angle are all different from each other, a polarizing plate and a liquid crystal display including the same are provided.

Description

A polarizing plate and a liquid crystal display device including the same {POLARIZING PLATE AND LIQUID CRYSTAL DISPLAY APPARATUS COMPRISING THE SAME}

The present invention relates to a polarizing plate and a liquid crystal display device including the same.

The liquid crystal display device is driven by transmitting light from a backlight unit through a light source-side polarizing plate, a liquid crystal panel, and a viewer-side polarizing plate in this order. The light emitted from the light source is diffused and emitted while passing through the backlight unit, and then is incident on the light source-side polarizing plate. Therefore, while passing through the light source-side polarizing plate, the liquid crystal panel, and the viewer-side polarizing plate, the contrast ratio decreases from the front to the side, and color deviation occurs. In order to solve the above problem, a retardation film may be used for a light source-side polarizing plate or a viewer-side polarizing plate. However, even if the retardation film is used, light compensation by the retardation film is not perfect from the front to the side, and light leakage inevitably occurs especially in the diagonal direction.

Accordingly, in order to solve the above problems, a method of using a condensing backlight unit is being considered. The condensing backlight unit is one in which an inverted prism condensing sheet is mounted instead of a normal normal prismatic diffusion sheet. The forward prism diffusion sheet is a sheet in which prisms are formed on the light exit surface of the sheet substrate, and the reverse prism condensing sheet is a sheet in which prisms are formed on the light incident surface of the sheet substrate. This is a light condensing-scattering system method in which the light condensed and emitted from the condensing backlight unit is transmitted through the liquid crystal panel to minimize the difference in contrast ratio according to the viewing angle and to secure the viewing angle by scattering light on the outermost surface of the polarizer on the viewing side. To this end, it is necessary to develop an optical element considering the condensing backlight unit. Although there is a method of installing a film containing scattering particles on the outermost surface of the viewing-side polarizing plate as the optical element, it has limitations in the degree of widening the viewing angle and/or the effect of improving the appearance.

The background art of the present invention is disclosed in Japanese Patent Publication No. 2006-251659 and the like.

An object of the present invention is to provide a polarizing plate capable of improving luminance, viewing angle, and contrast ratio from the front and side when applied to a liquid crystal display device having a condensing backlight unit.

Another object of the present invention is to provide a polarizing plate excellent in front contrast ratio improvement, side contrast ratio improvement, and appearance improvement effect when applied to a liquid crystal display device having a condensing backlight unit.

Another object of the present invention is to provide a polarizing plate capable of reducing the deviation of the ratio of the luminance value at the side to the luminance value at the front according to the lateral angle when applied to a liquid crystal display device having a condensing backlight unit. .

Another object of the present invention is to provide a condensing backlight unit, improve luminance, viewing angle, and contrast ratio from the front and side, and to reduce the deviation of the ratio of the luminance value from the front to the luminance value from the side according to the lateral angle. It is to provide a liquid crystal display device that can be lowered.

The polarizing plate of the present invention is a polarizer; and a pattern layer formed on the light exit surface of the polarizer, wherein the pattern layer includes a first resin layer and a second resin layer sequentially formed from the polarizer, and the first resin layer and the second resin layer are A pattern part is formed at the interface, the pattern part is composed of two or more pattern groups that are repeatedly arranged, the pattern group includes two or more engraved optical patterns, and two or more of the engraved optical patterns are selected from the pattern group. More than two have different aspect ratios and different base angles.

2.1, the intaglio optical pattern may have an aspect ratio of 0.3 to 3.0.

In 3.1-2, a difference between a maximum aspect ratio and a minimum aspect ratio among the engraved optical patterns in the pattern group may be 0.5 or more.

In 4.1-3, the base angle of the intaglio optical pattern may be 60° to 90°.

In 5.1-4, a difference between a maximum base angle and a minimum base angle among the intaglio optical patterns in the pattern group may be 5° or more.

In 6.1-5, the intaglio optical pattern may be a pattern having a flat surface formed at the top and having an N-gonal cross section (N is an integer of 4 to 10).

In 7.1-6, the intaglio optical patterns within the pattern group may be continuously formed without flat portions.

In 8.1-7, a flat part may not be formed or a flat part may be further formed between the pattern group and the immediately adjacent pattern group.

In 9.1-8, the intaglio optical pattern may be formed in a stripe-like elongated form in the longitudinal direction of the intaglio optical pattern.

In 10.1-9, the angle between the longitudinal direction of the intaglio optical pattern and the absorption axis of the polarizer among the polarizers is -20° to 20° and 70° to 110° when the absorption axis of the polarizer is 0°. , or -70° to -110°.

In 11.1-10, the first resin layer may have a higher refractive index than the second resin layer.

In 12.1-11, the absolute value of the difference in refractive index between the first resin layer and the second resin layer may be 0.05 or more.

In 13.1-12, the number of the engraved optical patterns in the pattern group may be 2 to 10.

In 14.1-13, the pattern group is composed of a total of two optical patterns, a first pattern and a second pattern, as the intaglio optical patterns, and the first pattern and the second pattern may have different base angles and aspect ratios. .

In 15.1-14, the pattern group is composed of a total of three optical patterns of a first pattern, a second pattern, and a third pattern continuously formed without a flat portion as the intaglio optical pattern, the first pattern and the second pattern. , two or more of the third patterns may have different base angles and aspect ratios.

In 16.1-15, the first resin layer may be a filling part filling at least a part of the intaglio optical pattern or a layer including the filling part.

In 17.1 to 16, a protective film may be further laminated on at least one of the light exit surface of the pattern layer and the light incident surface of the pattern layer.

In 18.1-17, at least one surface treatment layer of a hard coating layer, a scattering layer, a low reflection layer, an ultra low reflection layer, a primer layer, an anti-fingerprint layer, an anti-reflection layer, and an antiglare layer may be further formed on at least one surface of the protective film. .

19. The liquid crystal display device of the present invention includes the polarizing plate of the present invention.

At 20.19, the liquid crystal display device may include a condensing backlight unit including a backlight unit, a light source-side polarizing plate, a liquid crystal panel, and the polarizing plate sequentially disposed, and the backlight unit having a reverse prism sheet.

In 21.19-20, the light collecting backlight unit is the ratio of the luminance value (L 30°) at the side (30° or -30°) to the luminance value (L _0° ) at the front (0 _° ) in the white mode ( W _30° = L _30° /L _0° ) is 0.1 to 0.5, the luminance value (L 60°) at the side (60° or -60°) relative to the luminance value (L _0° ) at the front (0° ₎ ) The ratio (W _{60 °} = L _{60 °} / L _{0 °} ) may be 0 to 0.1.

The present invention provides a polarizing plate capable of improving luminance, viewing angle, and contrast ratio from the front and side when applied to a liquid crystal display device having a condensing backlight unit.

The present invention provides a polarizing plate excellent in front contrast ratio improvement, side contrast ratio improvement, and appearance improvement effect when applied to a liquid crystal display device having a light collecting backlight unit.

The present invention provides a polarizing plate capable of reducing a deviation of a ratio of a luminance value on a side surface to a luminance value on a front surface according to a side angle when applied to a liquid crystal display device having a condensing backlight unit.

The present invention has a condensing backlight unit, can improve luminance, viewing angle, and contrast ratio from the front and side, and can reduce the deviation of the ratio of the luminance value from the side to the luminance value from the front according to the side angle. A liquid crystal display device was provided.

1 is a cross-sectional view of a polarizing plate according to an exemplary embodiment of the present invention.
FIG. 2 is a cross-sectional view of a pattern group of the polarizing plate of FIG. 1 .
3 is a cross-sectional view of a pattern group of a polarizing plate according to another embodiment of the present invention.
4 is a cross-sectional view of a pattern group of a polarizing plate according to another embodiment of the present invention.
5 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention.
6 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention.
7 is a cross-sectional view of a pattern group of a polarizing plate according to another embodiment of the present invention.
8 is a luminance profile showing a ratio of a luminance value (L 0° ) in a front side (0 _° ) to a luminance value in a side surface in a white mode for light emitted from a condensing backlight unit and a typical backlight unit, respectively.
9 is a cross-sectional view of a condensing backlight unit according to an embodiment of the present invention.
10 is a cross-sectional view of a polarizing plate of Comparative Example 4.
11 to 18 show a luminance profile (solid line) of the condensing backlight unit and a luminance profile (dashed one-dotted line) when the polarizer of the embodiment is applied to the condensing backlight unit.
19 to 22 show a luminance profile (solid line) of the condensing backlight unit and a luminance profile (dashed one-dotted line) when a polarizer of a comparative example is applied to the condensing backlight unit.
23 shows a ratio (solid line) of a luminance value at a side angle to a luminance value at the front for light emitted from a conventional backlight unit and a luminance profile when the polarizing plate of Example 4 is applied to a conventional backlight unit (1 point). dashed line).

With reference to the accompanying drawings, the embodiments will be described in detail so that those skilled in the art can easily carry out the embodiments. This invention may be embodied in many different forms and is not limited to the embodiments set forth herein. In order to clearly describe the present invention in the drawings, parts irrelevant to the description are omitted, and the same reference numerals are attached to the same or similar components throughout the specification.

In this specification, "upper" and "lower" are defined based on the drawings, and depending on the perspective, "upper" may be changed to "lower" and "lower" to "upper", and "on" or What is referred to as “on” may include not only immediately above but also the case of intervening other structures in the middle. On the other hand, what is referred to as "directly on", "directly on" or "directly formed" or "directly in contact with" means that no other structure is intervened.

In this specification, "horizontal direction" and "vertical direction" mean a long direction and a short direction of a rectangular liquid crystal display screen, respectively. In this specification, "front" and "side" are based on the horizontal direction, when the front is (0 °), the left end point is (-90 °), and the right end point is (90 °), the side is ( -30°), (-45°), (-60°) or (30°), (45°), (60°).

In this specification, "top part" means the highest part of the intaglio optical pattern.

In the present specification, “aspect ratio” means the ratio of the maximum height to the maximum width of an engraved optical pattern (maximum height/maximum width).

In the present specification, "basic angle" means an angle formed between the maximum width of the optical pattern and an inclined surface directly connected to the maximum width of the optical pattern. For example, referring to FIG. 2 , the maximum width W1 of the optical pattern 230A and the inclined surface 231 directly connected to the maximum width W1 of the optical pattern 230A form an angle α1 with each other. it means. For example, referring to FIG. 3 , the angle α1 between the maximum width W1 of the optical pattern 240A and the inclined surface 241 directly connected to the maximum width W1 of the optical pattern 240A is it means.

In this specification, "plane direction retardation (Re)" is a value at a wavelength of 550 nm, and is represented by the following formula A:

<Formula A>

Re = (nx - ny) x d

(In the above formula A, nx and ny are refractive indices of the slow axis and fast axis directions of the protective film at a wavelength of 550 nm, respectively, and d is the thickness of the protective film (unit: nm)).

In this specification, “(meth)acryl” means an acryl and/or methacrylic.

Unless otherwise specified herein, lateral 30° means one or more of lateral 30° and lateral -30°, lateral 45° means one or more of lateral 45° and lateral -45°, and lateral 60° may mean one or more of lateral 60 ° and lateral -60 °.

8 is a ratio of the luminance value at the side to the luminance value (L 0°) at the front ( _0° ) in a white mode with respect to light emitted from the condensing backlight unit (one-dot chain line in FIG. 8). ) and the ratio of the luminance value at the side to the luminance value at the front (0°) (L _0° ) in the white mode for the light emitted from the conventional backlight unit (solid line in FIG. 8).

In the case of the light collecting backlight unit, the ratio of the luminance value (L 30° ) at the side (30° or -30°) to the luminance value (L _0° ) at the front (0°) in the white mode (W _{30 °} = L _30° /L _0° ) may be approximately 0.1 to 0.5, specifically 0.1 to 0.15, more specifically 0.11, relative to the luminance value (L _0° ) from the front (0°) side (60° or The ratio (W _60° = L _{60 °} /L _0° ) of the luminance value (L 60° ) at −60°) may be about 0 to 0.1, specifically 0 to 0.05, and more specifically 0.

On the other hand, in the case of a typical backlight unit, the ratio of the luminance value (L 30° ) at the side (30° or -30°) to the luminance value (L _0° ) at the front (0 _° ) in the white mode. (W _{30 °} = L _{30 °} / L _{0 °} ) may be approximately 0.5 to 0.6, for example greater than 0.5 and less than or equal to 0.6, and the luminance value (L ₀ ° ) from the front (0 °) to the side (60 °) The ratio (W _60° = L _{60 °} /L _0° ) of the luminance value (L 60° ) at ° or -60° may be approximately 0.1 to 0.2.

As such, as shown in FIG. 8 , the concentrating backlight unit exhibits a luminance profile completely different from that of a normal backlight unit. The 'normal backlight unit' refers to a backlight unit not provided with an inverse prism condensing sheet, specifically a backlight unit provided with a forward prism diffusion sheet.

The inventor of the present invention is a viewer-side polarizing plate for emitting light emitted from a condensing backlight unit having an inverted prism, wherein the viewer-side polarizing plate includes a polarizer and a pattern layer formed on a light exit surface of the polarizer, the pattern layer comprising: A liquid crystal having a condensing backlight unit by including a first resin layer and a second resin layer, and having a pattern portion in which a pattern group described in detail below is repeatedly formed at an interface between the first resin layer and the second resin layer. When applied to a display device, it is confirmed that the luminance, viewing angle, and contrast ratio can be improved from the front and side, and the deviation of the ratio of the luminance value from the side to the luminance value from the front can be reduced according to the angle of the side, and the present invention has been completed.

The pattern group includes two or more engraved optical patterns, and at least two of the engraved optical patterns have different aspect ratios and base angles.

Hereinafter, a polarizing plate according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2 . 1 is a cross-sectional view of a polarizing plate according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a pattern group of the polarizing plate of FIG. 1 .

Referring to FIG. 1 , the polarizer 10 may include a polarizer 100 , a pattern layer 200 sequentially formed on a light exit surface (upper surface) of the polarizer 100 , and a protective film 300 .

By excluding the protective film 300 for the purpose of manufacturing the polarizing plate and thinning the polarizing plate, a polarizing plate having only the pattern layer 200 formed on the upper surface of the polarizer 100 without the protective film 300 may also be included in the scope of the present invention.

In addition, a polarizing plate in which the protective film 300 is formed between the polarizer 100 and the pattern layer 200 may also be included in the scope of the present invention. That is, the position of the protective film in the polarizing plate is not particularly limited.

pattern layer

The pattern layer 200 is formed between the polarizer 100 and the protective film 300 to emit polarized light incident from the polarizer 100 to the protective film 300 .

The pattern layer 200 is composed of a first resin layer 210 and a second resin layer 220 facing the first resin layer 210 . In one embodiment, the pattern layer 200 is composed of only the first resin layer 210 and the second resin layer 220, in which the first resin layer 210 and the second resin layer 220 are in direct contact with each other. It can be.

The first resin layer 210 is formed on the light incident surface of the second resin layer 220 . A pattern portion described in detail below is formed at the interface between the first resin layer 210 and the second resin layer 220 .

The pattern unit is composed of two or more pattern groups 230 that are repeatedly arranged. The pattern groups 230 in the pattern unit may be the same as or different from each other.

1 shows a polarizing plate without flat portions between pattern groups 230 and pattern groups 230 , flat portions may be formed between pattern groups 230 and 230 . This will be described in detail below.

In the pattern group 230, two or more engraved optical patterns are continuously formed without a flat portion, and two or more of the engraved optical patterns have different aspect ratios and base angles. When two or more of the intaglio optical patterns have different base angles but the same aspect ratio, the viewing angle improvement effect is reduced at all 30°, 45°, and 60° side angles, or the luminance is abnormally high or low at certain angles, resulting in unevenness when viewed from the side. There may be a problem with the image quality. Even when two or more of the intaglio optical patterns have different aspect ratios but have the same base angles, the same problem as described above may occur.

Referring to FIG. 2, the pattern group 230 is composed of a total of three optical patterns: a first pattern 230A, a second pattern 230B, and a third pattern 230C, which are continuously formed without a flat portion. . At least two of the first pattern 230A, the second pattern 230B, and the third pattern 230C have different base angles and aspect ratios.

In this case, as shown in FIG. 2, the 'basic angle' may be the case where the basic angles on both sides of the first pattern 230A, the second pattern 230B, and the third pattern 230C are the same. defined as the largest angle.

1 and 2 show a case in which flat portions are continuously formed between intaglio optical patterns in a pattern group. However, a flat portion may be further formed between the engraved optical patterns in the pattern group, which will be described in detail below.

In one embodiment, the first pattern, the second pattern, and the third pattern may have different base angles and aspect ratios.

In another embodiment, the first pattern and the second pattern may have different base angles and aspect ratios.

In another embodiment, the first pattern and the third pattern may have different base angles and aspect ratios.

In another embodiment, the base angle and aspect ratio of the second pattern and the third pattern may be different from each other.

In one embodiment, the optical patterns within the pattern group may be continuously formed in the order of increasing base angles. That is, referring to FIG. 2 , the basic angle α1 of the first pattern 230A < the basic angle α2 of the second pattern 230B < the basic angle α3 of the third pattern 230C. At this time, in one embodiment, the aspect ratio of the first pattern 230A < the aspect ratio of the second pattern 230B, the aspect ratio of the third pattern 230C ≤ the aspect ratio of the second pattern 230B, the first pattern 230A The aspect ratio of ≤ may be the aspect ratio of the third pattern 230C.

2 shows that the pattern group 230 is formed of three engraved optical patterns, but the number of optical patterns in the pattern group can be adjusted according to the degree of condensation of light emitted from the condensing backlight, luminance, thickness of the polarizer, and the like. For example, the number of intaglio optical patterns in the pattern group may be 2 to 10, specifically 2 to 5, and more specifically 2 to 3.

In one embodiment, the boundary points between the first pattern 230A, the second pattern 230B, and the third pattern 230C, each of which is an engraved optical pattern within the pattern group, may be in contact with each other and may be on the same straight line. .

The average value of the aspect ratio of each of the first pattern 230A, the second pattern 230B, and the third pattern 230C or the pattern group within the pattern group is 0.3 to 3.0, specifically 1.0 to 3.0, more specifically 1.0 to 2.0 This can be. Within the above range, an effect of improving a viewing angle and an effect of uniform lateral luminance may be provided.

In one embodiment, the difference between the maximum aspect ratio and the minimum aspect ratio in the intaglio optical patterns in the pattern group, that is, the first pattern, the second pattern, and the third pattern, is 0.5 or more, specifically 0.5 to 2.5, more specifically 0.5 to 1.0 It can be. Within this range, an effect of improving a viewing angle and uniform lateral luminance may be exhibited.

The base angles α1, α2, and α3 of each of the first pattern 230A, the second pattern 230B, and the third pattern 230C or the average value of the base angles of patterns within the pattern group is 60° to 90°, specifically 60°. ° or more and less than 90 °, more specifically 75 ° to 85 °. Within the above range, a viewing angle improvement effect and a uniform lateral luminance effect may be provided.

In one embodiment, the difference between the maximum basic angle and the minimum basic angle in the optical patterns in the pattern group, that is, the first pattern, the second pattern, and the third pattern, is 5° or more, specifically 5° to 25°, more specifically 5° to 25°. It can be 10°. Within this range, an effect of improving a viewing angle and uniform lateral luminance may be obtained.

In each of the first pattern, the second pattern, and the third pattern, both base angles may be the same or different from each other. Preferably, in each of the first pattern, the second pattern, and the third pattern, both base angles are equal to each other.

Maximum widths W1 , W2 , and W3 of the first pattern 230A, the second pattern 230B, and the third pattern 230C may be the same as or different from each other. For example, each of the maximum widths W1 , W2 , and W3 may be 1 μm to 50 μm, for example, 1 μm to 20 μm. Within the above range, the viewing angle can be improved and a uniform lateral luminance effect can be obtained, and pixel moiré with the liquid crystal panel can be avoided.

Maximum heights h1 , h2 , and h3 of the first pattern 230A, the second pattern 230B, and the third pattern 230C may be the same as or different from each other. For example, each of the maximum heights h1 , h2 , and h3 may be 1 μm to 50 μm, for example, 1 μm to 20 μm. Within the above range, an effect of improving a viewing angle and uniform lateral luminance is obtained, and pixel moiré with a liquid crystal panel can be avoided.

FIG. 2 shows a trapezoidal pattern in which the inclined surfaces 231, 232, and 233 are connected by the flat surface at the top of the first pattern 230A, the second pattern 230B, and the third pattern 230C, respectively. . However, the present invention is not limited thereto. The flat surface may be additionally formed with irregularities or may be changed to a curved surface, but may be preferably a flat surface.

The intaglio optical pattern is a plane with an inclined surface or an angled plane, and may be a pattern with an N-gonal cross section (N is an integer of 4 to 10) including a trapezoid with a flat surface formed at the top as well as a triangular pattern in cross section. there is. This will be described in detail below. Preferably, the optical pattern may have a trapezoidal pattern in cross section.

Each optical pattern within the pattern group may have the same or different shape. Preferably, the manufacturing process of the polarizing plate can be facilitated by making the shape of the optical pattern the same.

In FIG. 2 , widths of the flat surfaces of the first pattern 230A, the second pattern 230B, and the third pattern 230C may be the same as or different from each other, and may be greater than 0 μm and less than or equal to 50 μm, for example, 1 It may be ㎛ to 20㎛, 1㎛ to 10㎛. Within the above range, the viewing angle can be improved and a uniform lateral luminance effect can be obtained, and pixel moiré with the liquid crystal panel can be avoided.

Referring back to FIG. 1 , the pattern unit is composed of pattern groups 230 that are repeatedly formed. 1 shows that the arrangement order of a first pattern, a second pattern, and a third pattern in each pattern group is the same. However, when comparing neighboring pattern groups, the arrangement order of the optical patterns within the pattern group may be the same or different.

Although not shown in FIG. 1 , each optical pattern in the pattern group may be formed in a stripe-shaped extension in the length direction of the optical pattern. Through this, an effect of improving the left and right viewing angles may be obtained. The "longitudinal direction of the optical pattern" means a direction different from, for example, a direction orthogonal to the maximum width direction of the optical pattern.

In one embodiment, the angle between the longitudinal direction of the optical pattern and the absorption axis of the polarizer 100 is -20° to 20°, 70° to 110°, when the absorption axis of the polarizer is 0°, or -70° to -110°. Within the above range, it is possible to avoid the pixel moiré phenomenon with the liquid crystal panel. Preferably, it may be 90° or -90°.

The first resin layer 210 may be a high refractive index pattern layer having a higher refractive index than the second resin layer 220 .

The absolute value of the difference in refractive index between the first resin layer 210 and the second resin layer 220 may be 0.05 or more, specifically 0.1 or more, more specifically 0.1 to 0.3, 0.1 to 0.2, or 0.15 to 0.2. Within this range, an effect of improving a viewing angle may be obtained.

The first resin layer 210 may have a refractive index of 1.50 to 1.70, specifically 1.55 to 1.70, and more specifically 1.60 to 1.70. Within the above range, the light diffusing effect may be large, manufacturing may be easy, and the light diffusing effect of polarized light and the viewing angle improvement effect may be large.

The first resin layer 210 may be a filling part filling at least a part of the intaglio optical pattern or a layer having the filling part. Preferably, the filling part may completely fill the intaglio optical pattern. When the filling part partially fills the intaglio optical pattern, the remaining part may be filled with air.

The first resin layer 210 may be formed of a composition for the first resin layer including a curable resin. The curable resin may include at least one of a UV curable resin and a heat curable resin, but is not limited thereto. The composition for the first resin layer may further include at least one of an initiator and an additive. The initiator may include at least one of a photocuring initiator and a thermal curing initiator, but is not limited thereto. Additives may include conventional additives known to those skilled in the art. For example, the additive may include, but is not limited to, one or more of a leveling agent, a surface conditioner, an antioxidant, an antifoaming agent, a UV absorber, and a light stabilizer. The composition for the first resin layer may include, but is not limited to, common solvents such as ethanol, propylene glycol monomethyl ether acetate, methyl ethyl ketone, and methyl isobutyl ketone for coatability of the composition.

In one embodiment, the first resin layer 210 may be non-adhesive and non-adhesive. When the first resin layer 210 is non-adhesive, the pattern layer may be laminated on the adherend, that is, the polarizer using an adhesive, an adhesive, or an adhesive.

In another embodiment, the first resin layer 210 may be adhesive. When the first resin layer 210 is adhesive, the pattern layer can be laminated on the adherend without additional adhesive, adhesive, or sticky adhesive, so that the effect of reducing the thickness of the polarizing plate can be obtained.

The upper surface of the second resin layer 220 may be a plane in contact with the protective film 300 and the lower surface may have the above-described intaglio optical pattern corresponding to the pattern group.

The second resin layer 220 may be a low refractive index pattern layer having a refractive index of 1.3 or more and less than 1.50, specifically 1.3 to 1.49. Within this range, the viewing angle improvement effect may be excellent.

The second resin layer 220 may be formed of a composition for a second resin layer including a curable resin. The curable resin may include at least one of a UV curable resin and a heat curable resin, but is not limited thereto. The composition for the second resin layer may also contain at least one of the aforementioned initiator, additive, and solvent.

The maximum thickness of the second resin layer 220 may be greater than 0 μm and less than 50 μm, for example, greater than 0 μm and less than 30 μm. Within this range, occurrence of warpage such as curl can be prevented.

Maximum thickness of the second resin layer 220 - The maximum height of the optical pattern in the pattern group (also referred to as 'thickness') is greater than 0 μm and less than or equal to 30 μm, for example greater than 0 μm and less than or equal to 20 μm, greater than 0 μm and less than or equal to 10 μm can be below Within the above range, an effect of increasing the surface hardness and sufficient adhesion to the protective film can be expected.

protective film

The protective film 300 is formed on the light exit surface of the pattern layer 200, and light passing through the pattern layer 200 is emitted through the protective film 300. The protective film 300 may support the pattern layer 200 .

In one embodiment, the protective film 300 may be directly formed with the second resin layer 220 of the pattern layer 200 to thin the polarizer 10 . The "directly formed" means that no adhesive layer, adhesive layer, or adhesive layer is interposed between the protective film 300 and the pattern layer 200 .

The protective film 300 may have a total light transmittance of 90% or more, for example, 90% to 100% in the visible ray region. Within this range, incident light can be transmitted without affecting it.

The protective film 300 may include an optically transparent resin film having a light incident surface and a light exit surface opposite to the light incident surface. The protective film may be made of a single layer of resin film, or a plurality of resin films may be laminated. The resin includes a cellulose ester-based resin including triacetylcellulose (TAC), a cyclic polyolefin-based resin including an amorphous cyclic polyolefin (COP), a polycarbonate-based resin, and polyethylene terephthalate (PET). Polyacrylate-based resins, including polyester-based resins, polyethersulfone-based resins, polysulfone-based resins, polyamide-based resins, polyimide-based resins, acyclic-polyolefin-based resins, polymethyl methacrylate resins, etc. It may include one or more of vinyl alcohol-based resins, polyvinyl chloride-based resins, and polyvinylidene chloride-based resins, but is not limited thereto.

The protective film 300 may be an unstretched film, but may be a retardation film or an isotropic optical film having a retardation within a predetermined range by stretching the resin in a predetermined manner. In one embodiment, the protective film may be an isotropic optical film having Re of 0 nm or more and 60 nm or less, specifically, 40 nm to 60 nm. It is possible to improve the image quality by compensating the viewing angle within the above range. The "isotropic optical film" means a film in which nx, ny, and nz (nz means the refractive index in the thickness direction at a wavelength of 550 nm) are substantially the same, and the "substantially same" means a slight error as well as the completely same case. Including all cases. In another embodiment, the protective film may be a retardation film having Re of 60 nm or more. For example, the protective film may have Re of 60 nm to 500 nm or 60 nm to 300 nm. For example, the protective film may have Re of 6,000 nm or more, 8,000 nm or more, specifically 10,000 nm or more, more specifically more than 10,000 nm, more specifically 10,100 nm to 30,000 nm, or 10,100 nm to 15,000 nm. Within this range, rainbow stains may not be visually recognized, and a diffusion effect of light diffused through the contrast ratio improving layer may be increased.

The protective film 300 may have a thickness of 5 μm to 200 μm, for example, 30 μm to 120 μm. It can be used for a polarizing plate within the above range.

Although not shown in FIG. 1 , at least one surface (at least one of an upper surface and a lower surface) of the protective film 300 includes a hard coating layer, a scattering layer, a low reflection layer, an ultra low reflection layer, a primer layer, an anti-fingerprint layer, an anti-reflection layer, and an anti-reflective layer. A surface treatment layer such as a glare layer may be further formed. The surface treatment layer may provide an additional function to the polarizer.

Even if a pattern layer is added to the upper surface of the polarizer, the polarizer 10 includes the above-described pattern layer, so that the total light transmittance is 40% or more, specifically 40% to 50%, and the polarization degree is 95% or more, specifically 95% to 100%. can Within this range, it can be used as a polarizing plate in a liquid crystal display.

polarizer

The polarizer 100 may polarize light incident from the liquid crystal panel and transmit it through the pattern layer 200 . The polarizer 100 is formed on the light incident surface of the pattern layer 200 .

The polarizer 100 may include a polyvinyl alcohol-based polarizer prepared by uniaxially stretching a polyvinyl alcohol-based film, or a polyene-based polarizer prepared by dehydrating a polyvinyl alcohol-based film. The polarizer 100 may have a thickness of 5 μm to 40 μm. Within this range, it can be used in an optical display device.

The polarizer 100 may include a polarizer and a protective film formed on at least one surface of the polarizer. The protective film may protect the polarizer to increase reliability of the polarizer and increase mechanical strength of the polarizer. The protective film may include a film containing the resin listed in the protective film 300 described above.

Although not shown in FIG. 1 , an adhesive layer is further formed on the lower surface of the polarizer 100 so that the polarizer can be adhered to a liquid crystal panel or the like.

In one embodiment, the polarizing plate may have an effect of securing luminance uniformity and improving a viewing angle on a side surface by satisfying Equations 1 and 2 below when a light collecting backlight unit is applied:

<Equation 1>

W _30° > W _45° > W _60°

<Equation 2>

W _60° > 0.2

(In Equation 1 and 2 above,

W _30° is the ratio of the luminance value (L 30° ) at the side (30° or -30°) to the luminance value (L _0° ) at the front ( _0° ) in white mode,

W _45° is the ratio of the luminance value (L 45° ) at the side (45° or -45°) to the luminance value (L _0° ) at the front (0 _°) in white mode,

W _60° is the ratio of the luminance value (L ₄₅ ° ) from the side (60° or -60°) to the luminance value (L _0° ) from the front (0°) in white mode)

Hereinafter, a polarizing plate according to another embodiment of the present invention will be described with reference to FIG. 3 . 3 is a cross-sectional view of a pattern group of a polarizing plate according to another embodiment of the present invention.

Referring to FIG. 3 , the polarizer is substantially the same as the polarizer of FIG. 1 except that the pattern group 240 is repeatedly disposed instead of the pattern group 230 .

The pattern group 240 is composed of a total of two intaglio optical patterns, a first pattern 240A and a second pattern 240B, which are continuously formed without a flat portion. The first pattern 240A and the second pattern 240B have different base angles and aspect ratios.

Referring to FIG. 3 , the first pattern 240A and the second pattern 240B show trapezoidal patterns in which inclined surfaces 241 and 242 are connected by a flat surface at the top, respectively. However, the present invention is not limited thereto, and the above-described N-shaped intaglio optical pattern may be provided.

The shape, the base angle α1, the maximum width W1, the maximum height h1, and the material of the first pattern 240A may be changed as described in FIGS. 1 and 2 above. The shape, the base angle α2, the maximum width W2, the maximum height h2, and the material of the second pattern 240B may be changed as described in FIGS. 1 and 2 above.

Hereinafter, a polarizing plate according to another embodiment of the present invention will be described with reference to FIG. 4 . 4 is a cross-sectional view of a pattern group of a polarizing plate according to another embodiment of the present invention.

Referring to FIG. 4 , the polarizer is substantially the same as the polarizer of FIG. 1 except that the pattern group 250 is repeatedly disposed instead of the pattern group 230 .

In the pattern group 250, flat portions 251 and 252 are additionally formed between the intaglio optical patterns 230A, 230B, and 230C, respectively. The flat portions 251 and 252 may perform a function of increasing transmittance by reducing front luminance deterioration.

When the flat portions 251 and 252 are formed, the period within the pattern group (that is, the sum of the maximum width of one flat portion and the maximum width of the intaglio optical pattern immediately adjacent to the flat portion) is 1 μm to 100 μm, specifically 3 μm to 50 μm. Within the above range, moiré with the panel can be avoided.

The ratio of the total sum of the maximum widths of the flat part to the total sum of the maximum widths (W1+W2+W3) of the intaglio optical patterns among the pattern groups may be 0 to 2, specifically 0 to 2 or less, 0 to 1, 0 to 1 or less. there is. Within the above range, an effect of improving a side viewing angle may be obtained.

The maximum width of the flat portions 251 and 252 may be 1 μm to 20 μm, specifically 1 μm to 10 μm. Within this range, pattern shaping can be facilitated, and appropriate transmittance and viewing angle improvement effects can be expected.

FIG. 4 shows a case in which flat portions 251 and 252 are formed between the engraved optical pattern 230A and the engraved optical pattern 230B, and between the engraved optical pattern 230B and the engraved optical pattern 230C, respectively. However, the flat portion may be formed on only one of these.

Hereinafter, a polarizing plate according to another embodiment of the present invention will be described with reference to FIG. 5 . 5 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention.

Referring to FIG. 5 , the polarizing plate 20 is substantially the same as the polarizing plate according to the exemplary embodiment of the present invention except that a pattern layer 260 is formed instead of the pattern layer 200 .

In the pattern layer 260 , flat portions 261 and 262 are formed between the pattern group 230 and the adjacent pattern group 230 , respectively. The flat portions 261 and 262 can facilitate pattern formability and secure appropriate transmittance.

The width of the flat portions 261 and 262 relative to the sum of the maximum widths of the intaglio optical patterns in the pattern group 203 (W1 + W2 + W3) or the total width of the pattern group 230 (the total width of 230) ( The ratio of L) may be from 0 to 1, specifically greater than 0 and less than or equal to 1. Within this range, it is possible to facilitate pattern formability and secure appropriate transmittance.

In one embodiment, each of the flat portions 261 and 262 may have a maximum width L of greater than 0 μm and less than 200 μm, specifically greater than 0 μm and less than 100 μm. Within this range, it is possible to facilitate pattern formability and secure appropriate transmittance.

Hereinafter, a polarizing plate according to another embodiment of the present invention will be described with reference to FIG. 6 . 6 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention.

Referring to FIG. 6 , the polarizing plate 30 is substantially the same as the polarizing plate according to one embodiment of the present invention except that the pattern layer 270 is formed instead of the pattern layer 200 .

The pattern layer 270 is substantially the same as the polarizer according to the embodiment of the present invention, except that the first resin layer is a layer having a filling part filling at least a part of the intaglio optical pattern. Therefore, the maximum thickness of the first resin layer is greater than the maximum value of the intaglio optical patterns among the pattern groups.

Hereinafter, a polarizing plate according to another embodiment of the present invention will be described with reference to FIG. 7 . 7 is a cross-sectional view of a pattern group in a polarizing plate according to another embodiment of the present invention.

Referring to FIG. 7 , the pattern group 280 is composed of a total of three optical patterns: a first pattern 280A, a second pattern 280B, and a third pattern 280B, which are continuously formed without a flat portion. . At least two of the first pattern 280A, the second pattern 280B, and the third pattern 280B have base angles α1, α2, and α3 and aspect ratios h1/W1, h2/W2, and h3/W3. different.

In the first pattern 280A, the second pattern 280B, and the third pattern 280B, an inclined surface connected to the top and the maximum width of each pattern is formed of two planes, and the planes are angled with each other. 7 shows an intaglio pattern having a hexagonal cross section, but the present invention is not limited thereto.

Although not shown in FIG. 7 , the above-described flat portion may be further formed between the pattern groups or within the pattern groups in the polarizer of FIG. 7 .

Hereinafter, a polarizing plate according to another embodiment of the present invention will be described.

The polarizing plate of this embodiment is substantially the same as the polarizing plate of one embodiment of the present invention except that the first resin layer is a low refractive index pattern layer having a lower refractive index than the second resin layer. Regarding the refractive index, the contents described in FIG. 1 are followed.

The liquid crystal display device of the present invention includes the polarizing plate of the present invention.

In one embodiment, the liquid crystal display device of the present invention may include a polarizing plate on the viewing side of the liquid crystal panel. The "visible-side polarizing plate" is a polarizing plate disposed facing the screen side of the liquid crystal panel, that is, the light source side.

In one embodiment, the liquid crystal display device may include a condensing backlight unit, a light source-side polarizing plate, a liquid crystal panel, and a viewing-side polarizing plate sequentially stacked, and the viewing-side polarizing plate may include the polarizing plate of the present invention. The "light source-side polarizing plate" is a polarizing plate disposed on the light source side.

The condensing backlight unit may include a light source, a light guide plate, and a condensing sheet. In one embodiment, referring to FIG. 9 , the light collecting backlight unit 600 may include a light source 610 , a light guide plate 620 , and a light collecting sheet 630 .

As the light source 610 and the light guide plate 620, those commonly used in liquid crystal displays may be used. The light collecting sheet 630 may include a base film and an inverted prism formed on a light incident surface of the base film. The inverted prism can increase the efficiency of light by totally reflecting the light emitted from the light guide plate by its pattern shape.

Although not shown in FIG. 9 , light efficiency may be further increased by further forming a reflective sheet on the lower surface of the light guide plate 620 .

The liquid crystal panel may adopt a vertical alignment (VA) mode, an IPS mode, a patterned vertical alignment (PVA) mode, or a super-patterned vertical alignment (S-PVA) mode, but is not limited thereto.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, the following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited to the following examples.

Example 1

A first resin layer (high refractive index layer) was formed with a composition containing an ultraviolet curable resin (Shinah T&C) having a refractive index of 1.62. A second resin layer (low refractive index layer) was formed with a composition containing an ultraviolet curable resin (Shinah T&C) having a refractive index of 1.47.

As a protective film, a coating layer was formed by applying a composition for a second resin layer to a predetermined thickness on one surface (light incident surface) of a polyethylene terephthalate (PET) film (Toyobo, TA044, thickness: 80 μm). An optical pattern was applied to the coating layer using a film having an optical pattern formed thereon, and a second resin layer was formed by UV curing with an amount of UV light of 500 mJ/cm ² . One surface of the prepared second resin layer was coated with the composition for the first resin layer and UV cured with a light amount of 500 mJ/cm ² to form a first resin layer. A polarizer having a three-layer structure of PET/PVA/COP was laminated on one surface (light incident surface) of the first resin layer to prepare a polarizing plate.

Table 1 below shows one pattern group among the pattern parts formed on the interface between the first resin layer and the second resin layer. In the pattern portion, the pattern group is repeatedly formed without a flat portion as shown in FIG. 1 .

Referring to Table 1 below, the pattern group consists of a total of three patterns of a first pattern, a second pattern, and a third pattern, which are formed in the order of the first pattern, the second pattern, and the third pattern without a flat part there is. The first pattern, the second pattern, and the third pattern are intaglio optical patterns each having a trapezoidal cross section. The first pattern, the second pattern, and the third pattern each have a base angle and an aspect ratio shown in Table 1 below. In each of the first pattern, the second pattern, and the third pattern, both base angles are the same.

Examples 2 to 3

In Embodiment 1, the pattern group consists of three patterns: a first pattern, a second pattern, and a third pattern, which are continuously formed in the order of the first pattern, the second pattern, and the third pattern without a flat part, A polarizing plate was manufactured in the same manner as in Example 1 except that the first pattern, the second pattern, and the third pattern each had a trapezoidal embossed pattern and had a base angle and an aspect ratio shown in Table 1 below.

Example 4

In Embodiment 1, the pattern group is composed of two patterns, a first pattern and a second pattern, which are continuously formed in the order of the first pattern and the second pattern without a flat portion, and the first pattern and the second pattern are A polarizing plate was manufactured in the same manner as in Example 1, except that each had a trapezoidal embossed pattern and had the base angle and aspect ratio of Table 1 below.

Example 5

A polarizing plate was manufactured in the same manner as in Example 1 except for the fact that flat portions were formed between the negative optical patterns in the pattern group in Example 1. The width of the flat portion was 5 μm.

Example 6

A polarizing plate was manufactured in the same manner as in Example 1, except that flat portions were formed between the pattern groups in Example 1. The width of the flat portion was 5 μm.

Example 7

In Example 1, a flat portion (the width of the flat portion is 5 μm) is formed between the intaglio optical patterns in the pattern group, and a flat portion (the width of the flat portion is 5 μm) is formed between the pattern groups, and the first resin layer and the second A polarizing plate was manufactured in the same manner as in Example 1, except that the refractive index between the resin layers was changed as shown in Table 1 below.

Example 8

In Example 7, a polarizing plate was manufactured in the same manner as in Example 7, except that the refractive indices of the first resin layer and the second resin layer were changed as shown in Table 1 below.

Comparative Example 1 and Comparative Example 2

In Embodiment 1, the pattern group consists of three patterns: a first pattern, a second pattern, and a third pattern, which are continuously formed in the order of the first pattern, the second pattern, and the second pattern without a flat portion, A polarizing plate was manufactured in the same manner as in Example 1, except that the first pattern, the second pattern, and the third pattern each had a trapezoidal embossed pattern and had a base angle and an aspect ratio shown in Table 2 below.

In Comparative Example 1, the aspect ratios of the first pattern, the second pattern, and the third pattern are all the same as 1.0, and the base angles are different. In Comparative Example 2, the base angles of the first pattern, the second pattern, and the third pattern are all the same as 80°, and the aspect ratios are different.

Comparative Example 3

In Example 1, a polarizing plate was manufactured in the same manner as in Example 1 except that a trapezoidal pattern having an aspect ratio of 1.0 and a base angle of 85 ° was continuously formed at the interface between the first resin layer and the second resin layer without a flat portion. .

Comparative Example 4

A first resin layer (low refractive index layer) was formed with a composition containing an ultraviolet curable resin (Shina T&C) having a refractive index of 1.47. A second resin layer (high refractive index layer) was formed with a composition containing an ultraviolet curable resin (Shinah T&C) having a refractive index of 1.62.

In Example 1, a polarizing plate was manufactured in the same manner as in Example 1 except that a trapezoidal pattern having an aspect ratio of 1.0 and a base angle of 85° and a flat part were alternately formed at the interface between the first resin layer and the second resin layer. The aspect ratio and base angle of each trapezoidal pattern are the same. 10 shows a schematic view of the polarizing plate prepared in Comparative Example 4. Referring to FIG. 10, the polarizing plate includes a polarizer 100; a pattern layer 400 including a first resin layer 420 and a second resin layer 410; The protective film 300 is sequentially formed, and trapezoidal patterns and flat portions are alternately formed at the interface between the first resin layer 420 and the second resin layer 410 .

For the polarizers prepared in Examples and Comparative Examples, models for measuring viewing angles were prepared, and viewing angle characteristics were evaluated at side angles in Table 1 below.

Light source side polarizer

A polarizer was prepared by stretching a polyvinyl alcohol film 3 times at 60° C., adsorbing iodine, and then stretching the polyvinyl alcohol film 2.5 times in an aqueous solution of boric acid at 40° C. A polarizing plate was prepared by attaching a triacetylcellulose film (80 μm in thickness) as a substrate layer to both sides of the polarizer with an adhesive for polarizing plates (Z-200, Nippon Goshei Co.). The prepared polarizing plate was used as a light source-side polarizing plate.

Viewer side polarizer

As the viewer-side polarizing plate, the polarizing plate prepared in Examples and Comparative Examples was used.

LCD module

The light source-side polarizing plate was adhered to the lower surface of the liquid crystal panel, and the viewer-side polarizing plate was adhered to the upper surface of the liquid crystal panel. At this time, the protective film among the viewing-side polarizing plates was positioned at the outermost part from the upper surface of the liquid crystal panel. A liquid crystal display module was manufactured by disposing a condensing backlight unit having a reverse prism optical sheet under the light source-side polarizing plate. When the ratio of the luminance value from the side to the luminance value from the front (0°) is calculated and graphed in the white mode with respect to the light emitted from the condensing backlight unit, a luminance profile as shown in the dashed-dot line in FIG. 8 is obtained. can Referring to FIG. 8, the percentage value of the ratio W30° of the luminance value at the side (30°) to the luminance value at the front (0°) is 11%, and the side (60°) for the luminance value at the front (0°). °) of the luminance value, the percentage value of W60° is 0%.

Using EZCONTRAST X88RC (EZXL-176R-F422A4, ELDIM) in white mode, measure the luminance values from the front (0°) to the right side (90°) and left side (-90°) in a spherical coordinate system did

In the white mode, the ratio of the luminance value at the side to the luminance value at the front (0°) was calculated, and the results are shown in FIGS. 11 to 1 .

In the white mode, the ratio of the luminance value at the side (30°) to the luminance value at the front (0°) W Percentage value of _30° , the luminance value at the front (0°) and the side (45°) The percentage value of the luminance value at W _{45 °} , the ratio of the luminance value at the side (60 °) to the luminance value at the front (0 °) W _{60 °} by calculating the percentage value in Tables 1 and 2 below shown in

Example One 2 3 4 5 6 7 8 1st pattern base angle 75 75 75 75 75 75 75 75 aspect ratio 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 2nd pattern base angle 80 80 80 80 80 80 80 80 aspect ratio 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 3rd pattern base angle 85 85 85 - 85 85 85 85 aspect ratio 1.0 1.5 2.0 - 1.0 1.0 1.0 1.0 refractive index 2nd resin layer 1.47 1.47 1.47 1.47 1.47 1.47 1.47 1.65 1st resin layer 1.62 1.62 1.62 1.62 1.62 1.62 1.62 1.45 flat part in pattern group doesn't exist doesn't exist doesn't exist doesn't exist has exist doesn't exist has exist has exist flat part between pattern groups doesn't exist doesn't exist doesn't exist doesn't exist doesn't exist has exist has exist has exist viewing angle characteristics W _30° 58 61 67 48 34 30 32 40 W _45° 44 46 48 41 43 41 29 44 W _60° 31 31 31 25 31 31 31 32 result Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 Fig. 17 Fig. 18

comparative example One 2 3 4 1st pattern base angle 75 80 85 85 aspect ratio 1.0 1.0 1.0 1.0 2nd pattern base angle 80 80 - - aspect ratio 1.0 1.5 - - 3rd pattern base angle 85 80 - - aspect ratio 1.0 2.0 - - refractive index 2nd resin layer 1.47 1.47 1.47 1.62 1st resin layer 1.62 1.62 1.62 1.47 flat part in pattern group doesn't exist doesn't exist doesn't exist has exist flat part between pattern groups doesn't exist doesn't exist doesn't exist has exist viewing angle characteristics W _30° 22 73 26 23 W _45° 26 70 9 6 W _60° 31 27 0 0 result Fig. 19 Fig. 20 Fig. 21 Fig. 22

*In Table 1 and Table 2, the unit of the basic angle is °, and the unit of the viewing angle characteristic is %.

As shown in Table 1 and FIGS. 11 to 18, the polarizing plate of the present invention has improved viewing angle characteristics at all 30°, 45°, and 60° sides when applied to a liquid crystal display having a condensing backlight unit. Deviations in viewing angle characteristics at 30°, lateral 45°, and lateral 60° were also low.

On the other hand, Comparative Example 1, in which two or more of each pattern in the pattern group has different base angles but the same aspect ratio, has viewing angle characteristics at all 30° side, 45° side, and 60° side, as shown in Table 2 and FIG. 19. this did not improve. In addition, in Comparative Example 2, where two or more of the patterns in the pattern group have different aspect ratios but have the same basic angles, the viewing angle characteristics were not improved at 60° side as shown in Table 2 and FIG. 20, and at 30° side, side There was a large deviation in viewing angle characteristics at 60° from the side compared to 45°.

In addition, in Comparative Example 3, where each pattern in the pattern group has the same base angle and aspect ratio, the viewing angle characteristics were not improved at all of the side 30°, side 45°, and side 60°, as shown in Table 2 and FIG. At 60°, there was no luminance value at all. In addition, Comparative Example 4 in which each pattern in the pattern group has the same base angle and aspect ratio and a flat portion is provided between the patterns has viewing angle characteristics at all 30° side, 45° side, and 60° side as shown in Table 2 and FIG. 22 was not improved, and in particular, there was no luminance value at 60° side.

(1) Using the polarizing plate of Example 4, a module for a liquid crystal display device was manufactured in the same manner as the viewing angle measurement in Table 1 above. Using EZCONTRAST X88RC (EZXL-176R-F422A4, ELDIM Co.), luminance values were measured in each of the white mode and black mode at the front (0°) of the spherical coordinate system. A ratio of luminance in the white mode to luminance in the black mode (A1) was calculated.

A module for a liquid crystal display was manufactured in the same way except that the light source-side polarizer was attached to both sides of the liquid crystal panel, and the ratio of luminance in the white mode to luminance in the black mode (A2) was calculated in the same way as above. did

The percentage value (contrast ratio) of the ratio of A1 to A2 was calculated and shown in Table 3 below.

Instead of measuring from the front (0 °), it was measured from the side (30 °) and side (60 °), and the percentage value of the ratio of A1 to A2 was calculated and shown in Table 3 below.

(2) A liquid crystal display module was manufactured in the same manner as in Table 1 using the polarizing plate of Example 4, but a conventional backlight unit provided with a positive prism optical sheet was placed under the light source side polarizing plate to display a liquid crystal display. A module for the device was manufactured. In the white mode with respect to the light emitted from the conventional backlight unit, a luminance profile as shown in the solid line in FIG. there is. Referring to FIG. 8, the percentage value of the ratio W30° of the luminance value at 30° side to the luminance value at the front (0°) is about 52%, and at 60° side to the luminance value at the front (0°). The percentage value of the ratio W60° of the luminance value is about 13%.

W _{30 °} , W _{45 °} , and W _{60 °} were calculated in the same manner as in Table 1, and are shown in Table 3 and FIG. 23 below.

In the same manner as in (1), the percentage values of the ratio of A1 to A2 were calculated at the front (0 °), side (30 °), and side (60 °), and are shown in Table 3 below.

In Table 4 below, percentage values of W _30° and W _60° in the condensing backlight and the normal backlight are shown.

Viewing angle characteristics (%) Contrast Ratio (%) W _30° W _45° W _60° Front (0°) Lateral (30°) Lateral (60°) When applied to condensing backlight 48 41 25 98 120 450 When applied to normal backlight 61 52 41 36 108 407

luminance profile W _30° W _60° condensing backlight 11 0 normal backlight 52 13

As shown in Table 4 above, it can be seen that the concentrating backlight unit and the normal backlight unit exhibit completely different luminance profiles at 30° and 60° side angles.

As shown in Table 3, when the polarizing plate of the present invention is applied to a liquid crystal display having a condensing backlight unit, viewing angle characteristics are improved at 30° side, 45° side, and 60° side, and front contrast ratio and side contrast ratio are all improved. .

On the other hand, as shown in Table 3 and FIG. 23, when the polarizing plate of the present invention was applied to a liquid crystal display having a conventional backlight unit, the front contrast ratio reduction was large, and the side contrast ratio improvement effect was small compared to the case of using a condensing backlight unit. . This means that the polarizing plate of the present invention works effectively when applied to a liquid crystal display having a condensing backlight unit.

Simple modifications or changes of the present invention can be easily performed by those skilled in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (21)

polarizer; And a pattern layer formed on the light exit surface of the polarizer, wherein the pattern layer includes a first resin layer and a second resin layer sequentially formed from the polarizer,
A pattern portion is formed at the interface between the first resin layer and the second resin layer,
The pattern part is composed of two or more pattern groups repeatedly arranged,
The pattern group includes two or more engraved optical patterns, and at least two of the engraved optical patterns in the pattern group have different aspect ratios and base angles,
In the pattern portion, the pattern groups are the same as each other, the polarizing plate.
The polarizing plate of claim 1, wherein the intaglio optical pattern has an aspect ratio of 0.3 to 3.0.
The polarizing plate of claim 1 , wherein a difference between a maximum aspect ratio and a minimum aspect ratio of the intaglio optical patterns in the pattern group is 0.5 or more.
The polarizing plate of claim 1, wherein the intaglio optical pattern has a base angle of 60° to 90°.
The polarizing plate according to claim 1, wherein a difference between a maximum base angle and a minimum base angle among the intaglio optical patterns in the pattern group is 5° or more.
The polarizing plate according to claim 1, wherein the intaglio optical pattern is a pattern having a flat surface formed at an apex and having an N-gonal cross section (N is an integer of 4 to 10).
The polarizing plate of claim 1 , wherein the intaglio optical patterns in the pattern group are continuously formed without a flat portion.
The polarizing plate of claim 1 , wherein a flat portion is not formed between the pattern group and a pattern group immediately adjacent thereto, or a flat portion is further formed.
The polarizing plate of claim 1, wherein the intaglio optical pattern is formed in a stripe-shaped extension in a longitudinal direction of the intaglio optical pattern.
The method of claim 1 , wherein an angle formed between the length direction of the intaglio optical pattern and an absorption axis of the polarizer among the polarizers is -20° to 20° and 70° to 110° when the absorption axis of the polarizer is 0°. , or -70° to -110° which is, a polarizer.
The polarizing plate of claim 1 , wherein the first resin layer has a higher refractive index than that of the second resin layer.
The polarizing plate of claim 1, wherein an absolute value of a difference in refractive index between the first resin layer and the second resin layer is 0.05 or more.
The polarizing plate according to claim 1, wherein the number of the intaglio optical patterns in the pattern group is 2 to 10.
The method of claim 1, wherein the pattern group is composed of a total of two optical patterns, a first pattern and a second pattern, as the intaglio optical patterns, and the first pattern and the second pattern have different base angles and aspect ratios. phosphorus, polarizer.
The method of claim 1, wherein the pattern group is composed of a total of three optical patterns of a first pattern, a second pattern, and a third pattern continuously formed without a flat portion as the intaglio optical patterns, and the first pattern and the second pattern are formed continuously. A polarizing plate wherein at least two of the patterns and the third patterns have different base angles and different aspect ratios.
The polarizing plate according to claim 1, wherein the first resin layer is a filling part filling at least a part of the intaglio optical pattern or a layer including the filling part.
The polarizing plate according to claim 1, wherein a protective film is further laminated on at least one of a light exit surface of the pattern layer and a light incident surface of the pattern layer.
The method of claim 17, wherein at least one surface treatment layer of a hard coating layer, a scattering layer, a low reflection layer, an ultra low reflection layer, a primer layer, an anti-fingerprint layer, an anti-reflection layer, and an antiglare layer is further formed on at least one surface of the protective film. , polarizer.
A liquid crystal display device comprising the polarizing plate of any one of claims 1 to 18.
20. The liquid crystal display according to claim 19, wherein the liquid crystal display includes a backlight unit, a light source-side polarizing plate, a liquid crystal panel, and the polarizing plate sequentially disposed, and the backlight unit includes a condensing backlight unit having a reverse prism sheet. Device.
21. The method of claim 20, wherein the collecting backlight unit is a ratio of a luminance value (L 30°) at a side surface (30° or -30°) to a luminance value (L _0° ) at a front surface (0 _° ) in a white mode. (W _30° = L _30° /L _0° ) is 0.1 to 0.5, the luminance value (L 60 at _the side (60° or -60°)) relative to the luminance value (L _0° ) at the front (0°) The ratio (W _{60 °} = L _{60 °} / L _{0 °} ) of _° ) is 0 to 0.1, a liquid crystal display device.

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