KR102514151B1 - Polarizing plate and optical display apparatus comprising the same - Google Patents

Abstract

A polarizer, a first optical pattern part laminated on an upper surface of the polarizer, a second optical pattern part laminated on an upper surface of the first optical pattern part, and filling between the first optical pattern part and the second optical pattern part A filling part, wherein first optical patterns spaced apart from each other are formed in the first optical pattern part, a second optical pattern is formed on a lower surface of the second optical pattern part, and the first optical pattern, the The filling part and the second optical pattern satisfy Equations 1 and 2, and a polarizing plate and an optical display device including the same are provided.

Description

Polarizing plate and optical display device including the same {POLARIZING PLATE AND OPTICAL DISPLAY APPARATUS COMPRISING THE SAME}

The present invention relates to a polarizing plate and an optical display device including the same. More specifically, the present invention relates to a polarizing plate that improves rainbow visibility in all directions including front and side views and at the same time implements contrast ratio and viewing angle improvement effects in all directions including front and side views, and an optical display device including the same. .

The liquid crystal display device operates by radiating light emitted from a backlight unit through a liquid crystal panel. Light from the backlight unit is incident perpendicularly to the screen of the liquid crystal display device. Therefore, the contrast ratio (CR) of the side surface of the screen of the liquid crystal display device is inevitably lowered. Therefore, development of an optical film that increases the lateral contrast ratio is in progress.

Recently, a technique for improving frontal and lateral contrast ratios and viewing angles by separately adding a patterned film to the light exit surface of a polarizer has been developed. However, in the case of the conventionally developed polarizing plate having a pattern layer, when external light is projected on the screen of an optical display device, a rainbow is generated in all directions from the front and side surfaces. The rainbow is a phenomenon separate from the effect of improving the viewing angle and contrast ratio by the pattern layer. Since the pattern layer for improving the viewing angle and contrast ratio must necessarily include the pattern structure, there is a limit to improving the rainbow by changing the pattern layer. Of course, it is possible to consider a method of improving the rainbow by controlling the retardation of the protective film mounted on the polarizing plate together with the pattern layer to a specific range. However, it may not be easy to control the phase difference to improve the rainbow for all protective films. In this way, there is a limit to improving the rainbow when the pattern layer is added compared to the polarizer without the pattern layer.

The background art of the present invention is disclosed in Korean Patent Registration No. 10-0934574 and the like.

An object of the present invention is to provide a polarizing plate with improved rainbow in all directions including front and side views.

Another object of the present invention is to provide a polarizing plate with improved contrast ratio and viewing angle in all directions including front and side views.

Another object of the present invention is to provide an optical display device having the polarizing plate of the present invention.

1. The polarizing plate of the present invention includes a polarizer, a first optical pattern part laminated on an upper surface of the polarizer, a second optical pattern part laminated on an upper surface of the first optical pattern part, and the first optical pattern part and the second optical pattern part. A filling part filling between the optical pattern parts, wherein the first optical pattern part has first optical patterns spaced apart from each other, and a second optical pattern is formed on a lower surface of the second optical pattern part, The first optical pattern, the filling part, and the second optical pattern satisfy Equation 1 and Equation 2 below:

[Equation 1]

R1 > R2

(In Equation 1, R1 is the refractive index of the second optical pattern, R2 is the refractive index of the first optical pattern)

[Equation 2]

R3 > R2

(In Equation 2, R3 is the refractive index of the filling part, R2 is the refractive index of the first optical pattern).

In 2.1, the second optical pattern unit may include a base portion and the second optical pattern formed on a lower surface of the base portion, and the base portion may satisfy Equations 4 and 5 below:

[Equation 4]

R1 ≥ R4

(In Equation 4, R1 is the refractive index of the second optical pattern, R4 is the refractive index of the base)

[Equation 5]

R3 ≥ R4

(In Equation 5, R3 is the refractive index of the filling part, R4 is the refractive index of the base part).

In 3.1-2, the second optical pattern may be an optical pattern having at least a curved surface.

In 4.1-3, the second optical pattern may include one or more of a microlens pattern, an embossing pattern, a lenticular lens pattern, and an embossing pattern.

In 5.1-4, the maximum width of the second optical pattern may be smaller than the period of the first optical pattern part and larger than the width of the first surface formed on the top of the first optical pattern.

In 6.1-5, the maximum width of the second optical pattern may be 0.5 to 4 times the period of the first optical pattern part.

In 7.1-6, the second optical patterns may be formed not to be spaced apart from each other.

In 8.1-7, the absolute value of the difference between the refractive index of the base part and the refractive index of the first optical pattern part may be 0 to 0.5.

In 9.1-8, the absolute value of the difference between the refractive index of the second optical pattern and the refractive index of the filling part may be 0 to 0.1.

In 10.1-9, the second optical pattern and the filling part may be integrally formed.

In 11.1-10, the first optical pattern may not be formed on the upper surface of the first optical pattern layer.

In 12.1-11, the first optical pattern part satisfies Equation 3 below, and the base angle of the first optical pattern may be 75° to 90°:

[Equation 3]

1 < P2/W2 ≤ 10

(In Equation 3, P2 is the period of the first optical pattern unit (unit: μm),

W2 is the maximum width of the first optical pattern (unit: µm).

In 13.1-12, the first optical pattern may be a pattern that is embossed and has a trapezoidal, square or rectangular cross-section.

In 14.1-13, the first optical pattern part may be non-adhesive or adhesive.

In 15.1-14, the maximum thickness of the first optical pattern part may be equal to or greater than the maximum height of the second optical pattern.

In 16.1-15, in the filling part, the minimum distance between the first optical pattern and the second optical pattern part may be 0 μm to 15 μm.

In 17.1-16, the second optical pattern may be a negative optical pattern or a positive optical pattern.

In 18.1-17, a protective layer may be further formed on the upper surface of the second optical pattern unit.

In 19.1-18, the protective layer may further include a surface treatment layer.

The optical display device of the present invention includes the polarizing plate of the present invention.

The present invention provides a polarizing plate with improved rainbow in all directions including the front and side surfaces.

The present invention provides a polarizing plate with improved contrast ratio and viewing angle in all directions including front and side views.

The present invention provides an optical display device having the polarizing plate of the present invention.

1 is a cross-sectional view of a polarizing plate according to an embodiment of the present invention.
2 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention.
3 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention.
4, (A) is a rainbow evaluation photograph of Example 1, (B) is a rainbow evaluation photograph of Comparative Example 1, and (C) is a rainbow evaluation photograph of Comparative Example 2.

With reference to the accompanying drawings, it will be described in detail so that those skilled in the art can easily practice the present invention by way of examples. 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. The length and size of each component in the drawings are for explaining the present invention, and the present invention is not limited to the length and size of each component described in the drawings.

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, and when based on (φ, θ) by a spherical coordinate system, the front is (0 °, 0 °), and the left end point When (180°,90°) and the right end point are (0°, 90°), the side means (0°, 60°) or (0°, 60°).

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

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

In this specification, “period” means the distance between neighboring optical patterns, for example, the sum of the maximum width of one optical pattern and the width of one flat part immediately adjacent to the optical pattern.

In this specification, "plane direction retardation (Re)" is represented by the following formula A:

<Formula A>

Re = (nx - ny) x d

(In Equation A, nx and ny are refractive indices of the corresponding passivation layer in the direction of the slow axis and the fast axis, respectively, at a wavelength of 550 nm, and d is the thickness (unit: nm) of the passivation layer).

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

In the present specification, when describing a numerical range, "X to Y" means X or more and Y or less (X≤ and ≤Y).

The inventor of the present invention is a polarizing plate having a first optical pattern part on an upper surface of a polarizer, a second optical pattern part having a second optical pattern part formed on a lower surface on an upper part of the first optical pattern part, and A filling part filling between the pattern part and the second optical pattern part is included, and the first optical pattern, the filling part, and the second optical pattern satisfy Equation 1 and Equation 2 below: As a result, It was confirmed that the viewing angle and contrast ratio can be improved in all directions including the front and side, and the rainbow can be improved in all directions including the front and side.

[Equation 1]

R1 > R2

(In Equation 1, R1 is the refractive index of the second optical pattern, R2 is the refractive index of the first optical pattern)

[Equation 2]

R3 > R2

(In Equation 2, R3 is the refractive index of the filling part, R2 is the refractive index of the first optical pattern).

In the present invention, light is transmitted through the filling part from the first optical pattern part having a lower refractive index than the filling part, and the transmitted light has a higher refractive index than the first optical pattern part and passes through the second optical pattern having a predetermined shape, thereby improving visibility and contrast ratio. At the same time, the rainbow was improved in all directions including the front and side. As such, in the present invention, the effect of improving the rainbow can be obtained by the refractive index relationship between the first optical pattern, the filling part, and the second optical pattern and the second optical pattern having a predetermined shape.

If either of Equations 1 and 2 is not satisfied, the effect of improving the viewing angle, contrast ratio, and rainbow of the present invention cannot be obtained properly. In addition, even when the second optical pattern is missing in the polarizing plate of the present invention or the second optical pattern unit is stacked between the first optical pattern unit and the polarizer, the viewing angle, contrast ratio and rainbow improvement effect of the present invention cannot be obtained properly. In addition, even when the second optical pattern is formed on the upper surface of the second optical pattern unit, that is, the outermost part of the second optical pattern unit, the viewing angle, contrast ratio, and rainbow improvement effect of the present invention cannot be obtained.

Hereinafter, a polarizing plate according to an embodiment of the present invention will be described with reference to FIG. 1 .

Referring to FIG. 1 , a polarizing plate includes a polarizer 400 , a first optical pattern unit 200A, a filling unit 300A, a second optical pattern unit 100A, and a protective layer 500 .

The first optical pattern part 200A, the filling part 300A, the second optical pattern part 100A, and the protective layer 500 are sequentially disposed on the upper surface of the polarizer 400 . The upper surface of the polarizer 400 may be a light exit surface or a light incident surface of the polarizer, but is preferably a light exit surface of the polarizer, so that the viewing angle, contrast ratio, and rainbow of the present invention are obtained without affecting the polarization function of the polarizer. improvement can be obtained.

The polarizing plate has a second optical pattern unit 100A on the filling unit 300A, and the second optical pattern unit 100A has a second optical pattern 110 formed on a lower surface, the first optical pattern, The filling part and the second optical pattern satisfy Equations 1 and 2 above. Through this, the polarizing plate can obtain a rainbow improvement effect in all directions including the front and side surfaces without affecting the viewing angle and contrast ratio improvement effect by the first optical pattern unit.

First optical pattern part

The first optical pattern unit 200A is formed on the upper surface of the polarizer 400, and light emitted from the polarizer 400 may be emitted through the first optical pattern unit 200A.

The first optical pattern unit 200A includes a plurality of first optical patterns 210 formed spaced apart from each other. Alternatively, as shown in FIG. 1 , the first optical pattern unit 200A may be a layer formed on an upper surface of which a plurality of first optical patterns 210 are spaced apart from each other.

Since the first optical pattern part 200A becomes a layer on which the first optical pattern 210 is formed, adhesion reliability can be increased when the first optical pattern part is directly adhered or bonded to the polarizer.

Referring to FIG. 1 , the first optical pattern unit 200A may be a layer formed on an upper surface of which embossed first optical patterns 210 are spaced apart from each other by a flat portion 220 . The “embossed” means that the first optical pattern 210 protrudes from the upper surface of the first optical pattern unit 200A.

The first optical pattern 210, preferably, the first optical pattern part 200A has a lower refractive index than the filling part 300A. The first optical pattern 210 has a shape of the first optical pattern described in detail below. Through this, the polarizing plate may have an effect of improving a viewing angle and a contrast ratio in all directions including front and side views.

The difference between the refractive index (R3) of the filling part (300A) and the refractive index (R2) of the first optical pattern 210 or the refractive index (R2) of the first optical pattern part (200A) R3 - R2 is 0.1 or more, specifically 0.1 to 0.1. 0.2, more specifically 0.12 to 0.16. Within the above range, an effect of improving a viewing angle and a contrast ratio in the front and side views may be further increased.

The difference between the refractive index R1 of the second optical pattern 110 and the refractive index R2 of the first optical pattern 210 or the refractive index R2 of the first optical pattern part 200A, R1 - R2 is 0.1 or more, specifically It may be 0.1 to 0.2, more specifically 0.12 to 0.16. Within the above range, the viewing angle and contrast ratio improvement effect in the front and side views may be further increased, and the rainbow improvement effect may be further increased.

In one embodiment, the refractive index R2 of the first optical pattern 210 or the first optical pattern portion 200A may be 1.55 or less, specifically less than 1.55, specifically 1.4 to 1.55, and more specifically 1.42 to 1.53. there is. Within the above range, an effect of improving a viewing angle and a contrast ratio in front and side views may be excellent, and a rainbow effect may be improved.

The first optical pattern part 200A may satisfy Equation 3 below, and the base angle θ of the first optical pattern 210 may be 75° to 90°. The base angle θ means an angle formed between the inclined surface 211 of the first optical pattern 210 and the line of the maximum width W2 of the first optical pattern. In this case, the inclined surface means an inclined surface directly connected to the flat part of the first optical pattern. Within the above range, the lateral contrast ratio can be improved and the contrast ratio can be increased at the same lateral viewing angle: Specifically, the base angle (θ) is 80° to 90°, and P2/W2 (the ratio of P2 to W2) is 1.2 to 90°. 8 can be:

[Equation 3]

1 < P2/W2 ≤ 10

(In Equation 3, P2 is the period of the first optical pattern unit (unit: μm),

W2 is the maximum width of the first optical pattern (unit: µm).

The first optical pattern 210 may include a first surface 212 formed at the top and one or more inclined surfaces 211 connected to the first surface 212 . 1 shows an optical pattern in which the first optical pattern 210 has a trapezoidal cross section, but the present invention is not limited thereto, and the first optical pattern may be a rectangular or square optical pattern in addition to an optical pattern having a trapezoidal cross section. may be

The first surface 212 is formed at the top, and the light reaching the first optical pattern 210 is further diffused by the first surface, thereby increasing the viewing angle and luminance, and increasing the light diffusion effect to minimize luminance loss. there is.

The first surface 212 is a flat surface and may facilitate a manufacturing process of the polarizing plate. However, the first surface may have fine irregularities or be a curved surface. When the first surface is formed as a curved surface, a lenticular lens pattern may be formed.

1 shows a first optical pattern 210 having a trapezoidal cross section (eg, a shape in which the top of a prism having a triangular cross section is cut, a cut-prism shape). However, an embossed pattern in which a first surface is formed on the top and an inclined surface is a curved surface (e.g., a cut-lenticular lens pattern in which the top of a lenticular lens pattern is cut, or a cut-micro lens in which the top of a microlens pattern is cut) pattern) may also be included in the scope of the present invention. In addition, a pattern having an N-gonal cross section such as a rectangle or a square (N is an integer of 3 to 20) may also be included.

The first surface 212 may have a width A2 of 0.5 μm to 30 μm, specifically, 1 μm to 15 μm. Within the above range, it can be used in an optical display device, and an effect of improving the contrast ratio can be expected.

The first optical pattern 210 may have an aspect ratio of 0.1 to 10, specifically 0.1 to 7.0, more specifically 0.1 to 5.0, and more specifically 0.1 to 1.0. Within the above range, the contrast ratio and viewing angle of the front and side surfaces may be improved.

The maximum height H2 of the first optical pattern 210 may be greater than 0 μm and less than 20 μm, specifically greater than 0 μm and less than 15 μm, and more specifically greater than 0 μm and less than 10 μm. The maximum width W2 of the first optical pattern 210 may be greater than 0 μm and less than 20 μm, specifically greater than 0 μm and less than 15 μm, and more specifically greater than 0 μm and less than 10 μm. Within this range, contrast ratio improvement, viewing angle improvement, and luminance improvement may be exhibited, and moiré and the like may not appear.

The flat part 220 may increase front luminance by emitting light passing through the first optical pattern part 200A to the filling part 300A.

The ratio of the maximum width W2 of the first optical pattern 210 to the width L2 of the flat portion 220 may be greater than 0 and less than or equal to 9, specifically 0.1 to 3, more specifically 0.15 to 2. . Within the above range, the difference between the front contrast ratio and the side contrast ratio may be reduced, the contrast ratio may be increased at the same side viewing angle and the same front viewing angle, and an anti-moiré effect may be obtained.

The width L2 of the flat portion 220 may be 1 μm to 50 μm, specifically 1 μm to 20 μm. Within the above range, there may be an effect of increasing the front luminance.

The period P2 may be 1 μm to 50 μm, specifically 1 μm to 40 μm. Moiré may be prevented while having an effect of improving a contrast ratio within the above range.

FIG. 1 illustrates a polarizing plate formed by spaced apart from each other, adjacent first optical patterns having the same base angle, first surface width, maximum height, maximum width, period, and width of a flat part, respectively. However, cases in which adjacent first optical patterns have different base angles, widths of the first surfaces, maximum heights, maximum widths, periods, and widths of the flat part may be included in the scope of the present invention.

Although not specified in FIG. 1, FIG. 1 shows that the first optical pattern is formed in a stripe-like extension in the longitudinal direction of the first optical pattern, but the first optical pattern may be formed in a dot shape. . The "dot" means that the first optical patterns are dispersed apart from each other. Preferably, the first optical pattern is formed to extend in a stripe shape, so that the left and right viewing angles can be enlarged.

The first optical pattern unit may be formed of a composition containing at least one of a conventional thermosetting resin and a photocurable resin (eg, UV curable resin) capable of securing the above-described refractive index. For example, the composition may include a resin such as (meth)acrylic, polycarbonate, urethane, or silicone resin. The composition may further include conventional additives known to those skilled in the art, such as an antistatic agent, a light diffusing agent, a tackifier, and a dispersing agent.

In one embodiment, the first optical pattern portion may be non-adhesive and non-adhesive. When the first optical pattern unit is non-adhesive, the first optical pattern unit may be laminated to the polarizer using an adhesive, an adhesive, or an adhesive. In another embodiment, the first optical pattern part may be adhesive. When the first optical pattern unit is adhesive, the first optical pattern unit may be directly laminated on the polarizer. For example, the first optical pattern part may be a pressure sensitive adhesive (PSA) layer.

The maximum thickness of the first optical pattern part may be equal to or greater than the maximum height of the first optical pattern. Preferably, as shown in FIG. 1, the maximum thickness of the first optical pattern unit > the maximum height of the first optical pattern, so that when the first optical pattern unit is adhesive, the first optical pattern unit can be stably adhered to the polarizer. .

filling part

The filling part 300A is formed between the first optical pattern part 200A and the second optical pattern part 100A and fills a space between the first optical pattern part 200A and the second optical pattern part 100A. . The filling part 300A allows the second optical pattern part 100A to be stably coupled to the first optical pattern part 200A, and at the same time, a contrast ratio improvement effect may be implemented.

In one embodiment, the filling part 300A may fill at least a part of the space. Preferably, the filling part can prevent loss of light emitted from the first optical pattern part by completely filling the space.

In one embodiment, the filling part may be formed by directly contacting the first optical pattern part and the second optical pattern part, respectively.

The filling part 300A has a higher refractive index than the first optical pattern 210 or the first optical pattern part 200A so that the light passing through the first optical pattern part 200A is emitted upward and at the same time from the front and side. contrast ratio can be improved. In one embodiment, the refractive index R3 of the filling part 300A may be 1.55 or more, specifically 1.55 to 1.65, and more specifically 1.57 to 1.65. Within this range, it is possible to improve the contrast ratio and the viewing angle in the front and side surfaces, and easily reach Equation 2 above.

The filling part 300A may be formed of a composition containing at least one of a conventional thermosetting resin and a photocurable resin capable of satisfying the refractive index. For example, the composition may include a resin such as (meth)acrylic, polycarbonate, urethane, or silicone resin. The composition may further include conventional additives known to those skilled in the art, such as an antistatic agent, a light diffusing agent, a tackifier, and a dispersing agent.

In one embodiment, the filling part 300A may be non-adhesive or adhesive.

As shown in FIG. 1 , the filling part 300A may be a resin layer formed of a composition containing the above resin. Alternatively, the filling part may fill the space between the first optical patterns formed to be spaced apart from each other according to the shape of the first optical pattern part. This will be described with reference to FIG. 2 .

In the filling part 300A, the minimum distance S between the first optical pattern 210 and the second optical pattern part 100A (hereinafter, referred to as flesh thickness) is 15 μm or less, specifically 0 μm to 15 μm. , 0 μm to 13 μm, more specifically 0 μm or greater than 0 μm and 10 μm or less. Within the above range, there may be an effect of increasing transmittance and lowering the thickness of the polarizer.

Second optical pattern part

The second optical pattern part 100A is formed on the upper surface of the filling part 300A and has the refractive index relationship and the second optical pattern 110 described below, so that the first optical pattern part 200A, the filling part ( 300A) can also implement the effect of improving the rainbow without affecting the contrast ratio and viewing angle of light emitted from the light source.

The second optical pattern unit 100A has the second optical pattern 110 formed only on the lower surface.

In one embodiment, the upper surface of the second optical pattern unit 100A may be a surface on which the second optical pattern is not formed. In one embodiment, the top surface of the second optical pattern unit 100A is flat, and the degree of coupling between the second optical pattern unit 100A and the protective layer 500 can be increased.

The second optical pattern 110 may be an optical pattern including at least a curved surface. Also, as in Equation 1, the refractive index R1 of the second optical pattern 110 is higher than the refractive index R2 of the first optical pattern 210 or the first optical pattern part 200A. Through this, the second optical pattern unit can improve the rainbow in the polarizing plate including the first optical pattern unit and the filling unit.

In one embodiment, the refractive index R1 of the second optical pattern 110 may be 1.55 or more, specifically 1.55 to 1.65, and more specifically 1.59 to 1.64. Within this range, it is easy to reach the difference in refractive index of Equation 1 and above, and rainbow visibility of the polarizing plate can be improved.

The second optical pattern 110 is formed by directly contacting the filling part 300A. The refractive index R1 of the second optical pattern 110 and the refractive index R3 of the filling part 300A are substantially the same, and the absolute value of the refractive index difference R1-R3 may be 0 to 0.1, specifically 0 to 0.05. there is. Within the above range, it can help implement the effects of the present invention.

In one embodiment, the second optical pattern 110 and the filling part 300A may be integrally formed. The "integrally formed" means that the second optical pattern and the filling part have the same composition and the same refractive index and are simultaneously formed during the manufacturing process of the polarizing plate.

The second optical pattern 110 may be an intaglio optical pattern or an embossed optical pattern. The "intaglio" means an optical pattern protruding from the lower surface of the second optical pattern unit toward the upper surface or the protective layer of the second optical pattern unit. When the second optical pattern is an intaglio optical pattern, the second optical pattern is filled with a material providing the aforementioned refractive index R1. The "embossed" means an optical pattern protruding from the lower surface of the second optical pattern part toward the filling part. When the second optical pattern is an embossed optical pattern, the second optical pattern is formed of a material providing the aforementioned refractive index R1. 1 illustrates a polarizing plate in which a second optical pattern is an intaglio optical pattern.

The second optical pattern 110 may be an optical pattern including (or having) at least a curved surface. In one embodiment, the second optical pattern 110 may be one or more of a microlens pattern, an embossing pattern, a lenticular lens pattern, and an embossing pattern. Preferably, the second optical pattern may be an embossing pattern or a microlens pattern.

As described in detail below, the second optical pattern is prepared by applying a pattern having a predetermined shape to the coating layer, filling the coating layer with a material providing the above-described refractive index R1, and then curing the coating layer. Accordingly, the second optical pattern is a pattern having a predetermined shape and a predetermined size, unlike being formed in a concavo-convex shape on the lower surface of the second optical pattern unit. In addition, as much as the first optical pattern is formed under the second optical pattern, the size compared to the first optical pattern should be considered.

The maximum width W1 of the second optical pattern 110 is less than 4 times the period P2 of the first optical pattern portion 200A, and the width of the first surface 212 of the first optical pattern 210 ( It is larger than A2). Through this, there may be an effect of improving rainbow visibility. In one embodiment, the maximum width W1 of the second optical pattern 110 is 0.5 to 4 times, specifically 1 to 3 times, more specifically, the period P2 of the first optical pattern portion 200A. It can be 1.5 times to 2.5 times. Within the above range, there may be a rainbow improvement effect.

In one embodiment, the maximum width W1 of the second optical pattern 110 may be greater than 0 μm and less than 50 μm, specifically greater than 0 μm and less than 40 μm, and more specifically greater than 0 μm and less than 30 μm. In the above range, there may be a light diffusion effect.

The maximum height H1 of the second optical pattern 110 may be greater than 0 μm and less than 25 μm, specifically greater than 0 μm and less than 20 μm, and more specifically greater than 0 μm and less than 15 μm. Within this range, there may be effects of light diffusion and improvement of rainbow visibility.

The aspect ratio of the second optical pattern 110 may be 0 to 2.0, specifically 0 to 1.0, more specifically 0 to 0.8, and more specifically 0 to 0.6. In this range, it may be from 0.2 to 0.5.

1 shows a polarizer having the same maximum width, height, and aspect ratio of the second optical pattern 110 . However, the maximum width, maximum height and/or aspect ratio of the second optical pattern may be different from each other.

The second optical patterns may be continuously formed without being spaced apart from each other as shown in FIG. 1 . However, the second optical patterns may be formed to be spaced apart from each other. Preferably, since the second optical patterns are continuously formed without being spaced apart from each other, the effect of improving rainbow visibility in all directions from the front and side surfaces may be excellent.

As long as the second optical pattern can have the above-described size relative to the first optical pattern unit, the arrangement of the first optical pattern is not particularly limited. For example, a part of the maximum width of the second optical pattern may be disposed to correspond to the first surface of the top of the first optical pattern.

The second optical pattern portion 100A includes a base portion 120 and a second optical pattern 110 formed on a lower surface of the base portion 120 . The base part 120 allows the second optical pattern 110 to be stably formed on the second optical pattern part and at the same time to stably form a protective layer on the second optical pattern part, and to form a gap between the second optical pattern part and the protective layer. to maintain a bonded relationship.

The second optical pattern portion, preferably the base portion, may be directly formed on the protective layer. The "directly formed" means that an adhesive layer, an adhesive layer, or an adhesive layer is not provided between the second optical pattern unit and the protective layer.

By securing a predetermined refractive index, the base part satisfies the following Equations 4 and 5 to further increase the effect of improving the rain protection visibility in all directions including the front and side surfaces of the polarizer:

[Equation 4]

R1 ≥ R4

(In Equation 4, R1 is the refractive index of the second optical pattern, R4 is the refractive index of the base)

[Equation 5]

R3 ≥ R4

(In Equation 5, R3 is the refractive index of the filling part, R4 is the refractive index of the base part)

In one embodiment, the refractive index difference R1 - R4 obtained from Equation 4 may be 0 or more, specifically 0 to 1, and more specifically 0 to 0.5. In one embodiment, the refractive index difference R3 - R4 obtained from Equation 5 may be 0 or more, specifically 0 to 1, and more specifically 0 to 0.5. Within the above range, there may be an effect of improving visibility.

In one embodiment, the refractive index (R4) of the base portion may be 2 or less, specifically 1 to 2, more specifically 1.5 to 1.7. Within this range, equations 4 and 5 can be easily reached, and diffusion and rainbow improvement effects can be obtained.

The base portion 120 may have the same refractive index as, greater than, or less than that of the first optical pattern or the first optical pattern portion. Preferably, the base portion 120 may have the same refractive index as or greater than that of the first optical pattern 210 or the first optical pattern portion 200A. In one embodiment, the absolute value of the difference between the refractive index R4 of the base part and the refractive index R2 of the first optical pattern or the first optical pattern part |R4-R2| is 0 to 0.5, specifically 0 to 0.3, more specifically 0 to 0.2 It can be. Within the above range, there may be an effect of improving visibility.

The maximum thickness of the base portion 120 may be the same as or different from the thickness of the second optical pattern portion. For example, the maximum thickness of the base portion may be 40 μm to 120 μm, specifically 60 μm to 100 μm. Within the above range, it can be used for a polarizing plate and can help improve the rainbow effect.

The minimum thickness of the base portion 120, that is, the minimum distance between the upper surface of the second optical pattern unit and the second optical pattern may be 0 μm to 10 μm, specifically 0 μm to 5 μm, greater than 0 μm and less than 10 μm. Within the above range, it may help to reduce the thickness of the polarizing plate and improve the rainbow effect.

polarizer

The polarizer 400 may polarize and emit light incident from the liquid crystal panel. The polarizer 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 400 may have a thickness of 5 μm to 40 μm. Within this range, it can be used in an optical display device.

The polarizer 400 alone may be included in the polarizer, but a protective layer may be further formed on at least one surface of the polarizer. As the protective layer, a protective layer detailed below may be applied.

protective layer

The protective layer 500 may be formed on the upper surface of the second optical pattern unit 100A to support the second optical pattern unit. Light passing through the second optical pattern unit may be emitted through the protective layer.

The protective layer 500 may be formed directly with the second optical pattern unit 100A to make the polarizer thinner. The “directly formed” means that no adhesive layer, adhesive layer, or adhesive layer is interposed between the protective layer and the second optical pattern unit. Of course, a polarizing plate in which an adhesive layer, an adhesive layer, or an adhesive layer is formed between the protective layer and the second optical pattern unit may also be included in the scope of the present invention.

The protective layer 500 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 layer 500 may be a protective film or a protective coating layer. Preferably, the degree of support for the first optical pattern layer may be excellent by using a protective film as a protective layer.

The protective film 500 may include a single-layer optically transparent resin film. However, the protective film may include a protective film in which a plurality of single-layer resin films are laminated. The protective film may be formed by melting and extruding a resin. If necessary, a further stretching process may be added. The resin is a cellulose ester-based resin including triacetyl cellulose, a cyclic polyolefin-based resin including an amorphous cyclic polyolefin, a polycarbonate-based resin, a polyester-based resin including polyethylene terephthalate (PET), poly Ethersulfone-based resins, polysulfone-based resins, polyamide-based resins, polyimide-based resins, acyclic-polyolefin-based resins, polyacrylate-based resins including polymethyl methacrylate resins, polyvinyl alcohol-based resins, poly At least one of a vinyl chloride-based resin and a polyvinylidene chloride-based resin may be included.

The protective film 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 are substantially the same, and "substantially the same" includes not only the completely identical film but also the film containing a slight error. 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, specifically 8,000 nm or more, 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 pattern layer may be increased.

The protective coating layer may be formed of an active energy ray-curable resin composition containing an active energy ray-curable compound and a polymerization initiator. The active energy ray-curable compound may include at least one of a cationically polymerizable curable compound, a radically polymerizable curable compound, a urethane resin, and a silicone-based resin. The cationically polymerizable curable compound may be an epoxy-based compound or an oxetane-based compound. The radically polymerizable curable compound includes a (meth)acrylate monomer having at least one (meth)acryloyloxy group in the molecule and a (meth)acrylate oligomer thereof.

The protective layer 500 may have a thickness of 5 μm to 200 μm, specifically, 30 μm to 120 μm. It can be used for a polarizing plate within the above range.

At least one surface of the protective layer 500, that is, at least one of the upper and lower surfaces of the protective layer is a surface treatment layer such as a primer layer, a hard coating layer, an anti-fingerprint layer, an anti-reflection layer, an anti-glare layer, a low-reflection layer, and an ultra-low-reflection layer. This may be further formed. The surface treatment layer may provide additional functions such as a protective layer or a polarizer.

Hereinafter, a polarizing plate according to another embodiment of the present invention will be described with reference to FIG. 2 .

Referring to FIG. 2 , the polarizer includes a polarizer 400, a first optical pattern unit 200A, a filling unit 300B, a second optical pattern unit 100A, and a protective layer 500.

Compared to the polarizing plate of FIG. 1 , it is substantially the same as the polarizing plate of FIG. 1 except for the fact that the thickness S of the fill part 300B is 0 μm. In the filling part 300B, the thickness of the flesh (S) is 0 μm, thereby obtaining the thinning effect of the polarizing plate, and at the same time, the second optical pattern 110 having a higher refractive index than the first optical pattern part and the filling part 300B are at least mutually By contacting and connecting, it is possible to enable continuous transmission of light.

Hereinafter, a polarizing plate according to another embodiment of the present invention will be described with reference to FIG. 3 .

Referring to FIG. 3 , the polarizing plate includes a polarizer 400 , a first optical pattern unit 200A, a filling unit 300C, a second optical pattern unit 100C and a protective layer 500 .

Compared to the polarizing plate of FIG. 1 , the second optical pattern portion is substantially the same as that of the polarizing plate of FIG. 1 except that the base portion 130 and the embossed optical pattern 140 are formed.

The optical display device of the present invention may include the polarizing plate of the present invention. In one embodiment, the optical display device may be a liquid crystal display device, and the polarizing plate of the present invention may be included as a viewer-side polarizing plate for the liquid crystal panel. The "visible-side polarizer" is disposed to face the screen side, that is, the light source side, with respect to the liquid crystal panel.

In one embodiment, the liquid crystal display device may include a backlight unit, a first polarizing plate, a liquid crystal panel, and a second polarizing plate sequentially stacked, and the second polarizing plate may include the polarizing plate of the present invention. In another embodiment, it may be included as a light source-side polarizing plate for the liquid crystal panel. The "light source-side polarizer" is disposed on the light source side with respect to the liquid crystal panel. In another embodiment, both the viewer-side polarizing plate and the light source-side polarizing plate of the liquid crystal panel may include the polarizing plate of the present invention.

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

(1) Manufacture of protective layer-second optical pattern part

As a protective layer, a polyethylene terephthalate (PET) film (DNP, DSG-17(Z), thickness: 90 μm, Re: 8,500 nm at a wavelength of 550 nm) was used. A coating layer was formed by coating a UV curable resin (SSC-4620, Shina TNC) to a predetermined thickness for the base portion of the second optical pattern portion on the lower surface of the PET film, and a predetermined intaglio pattern was applied to the coating layer and cured. . Then, the intaglio pattern was filled with a UV curable resin (SSC-6000, Shina TNC) to form a second optical pattern part. The refractive index of the base part is 1.60, and the refractive index of the second optical pattern is 1.62. Specific specifications of the second optical pattern are shown in Table 1 below.

(2) Manufacture of protective layer-second optical pattern part-filling part-first optical pattern part

A UV curable resin (SSC-6000, Shinart & Co.) was coated on the lower surface of the second optical pattern part to a predetermined thickness to form a coating layer, and a predetermined intaglio pattern was applied to the coating layer and cured. Then, the intaglio pattern was filled with an acrylic adhesive resin (PL5840, SAIDEN) to form a filling part and a first optical pattern part. The refractive index of the filling part is 1.62, and the refractive index of the first optical pattern part is 1.49. Specific specifications of the first optical pattern are shown in Table 1 below.

(3) Polarizing plate manufacturing

A polyvinyl alcohol film was uniaxially stretched 3 times at 60°C, iodine was adsorbed, and then stretched 2.5 times in an aqueous solution of boric acid at 40°C to prepare a polarizer (thickness: 22 μm). A polarizing plate was manufactured by attaching the first optical pattern part of the laminate prepared in (2) to the upper surface of the polarizer.

Examples 2 to 3

In Example 1, the evaluation was performed in the same manner as in Example 1 except that the shapes of the first and second optical patterns were changed as shown in Table 1 below.

Comparative Example 1

A polarizing plate was manufactured in the same manner as in Example 1 except that only the protective layer was formed on the upper surface of the polarizer without the second optical pattern part, the filling part, and the first optical pattern part in Example 1.

Comparative Example 2

A polarizing plate was manufactured in the same manner as in Example 1 except that in Example 1, the first optical pattern part-filling part-protective layer were formed in the order on the upper surface of the polarizer without the second optical pattern part.

Comparative Example 3

A polarizing plate was manufactured in the same manner as in Example 1, except that in Example 1, the first optical pattern part-filling part-base part-protective layer were formed in the order on the upper surface of the polarizer without the second optical pattern.

Example comparative example One 2 3 One 2 3 Base Refractive Index (R4) 1.60 1.60 1.60 - - 1.60 2nd
optical pattern pattern micro lens micro lens micro lens - - - engrave/emboss intaglio intaglio relief - - - maximum width 30㎛ 30㎛ 30㎛ - - - maximum height 13㎛ 13㎛ 13㎛ - - - whether to separate no spacing no spacing no spacing - - - Refractive index (R1) 1.62 1.62 1.62 - - - Filled part refractive index (R3) 1.62 1.62 1.62 - 1.62 1.62 No. 1
optical pattern pattern section trapezoid trapezoid trapezoid - trapezoid trapezoid maximum width 7㎛ 7㎛ 7㎛ - 7㎛ 7㎛ height 7㎛ 7㎛ 7㎛ - 7㎛ 7㎛ 1st face width 3.5㎛ 3.5㎛ 3.5㎛ - 3.5㎛ 3.5㎛ flat part width 7 μm 7㎛ 7㎛ - 10㎛ 10㎛ to give 14㎛ 14㎛ 14㎛ - 14㎛ 14㎛ base angle 86° 86° 86° - 86° 86° Refractive index (R2) 1.49 1.49 1.49 - 1.49 1.49 polarizer structure Figure 2 Figure 1 Figure 3 - - -

The following physical properties were evaluated for the polarizing plates of Examples and Comparative Examples, and the results are shown in Table 2 and FIG. 4 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.

LCD module

A module for a liquid crystal display device was manufactured by sequentially assembling the light source-side polarizing plate prepared above, the liquid crystal panel (PVA mode), and the polarizing plate prepared in the above Examples and Comparative Examples. Among the polarizers prepared in Examples and Comparative Examples, the protective layer was assembled to come out to the outermost part. A liquid crystal display including a single edge-type LED light source by assembling an LED light source, a light guide plate, and a liquid crystal display module (Except for the configuration of the liquid crystal display module of Examples and Comparative Examples, Samsung TV (55-inch, manufactured in 16 years) Model name: UN55KS8000F) and the same configuration) were manufactured.

(1) Relative luminance (unit: %) and illuminance (unit: Lx): For the liquid crystal display module manufactured above, EZCONTRAST X88RC (EZXL-176R-F422A4, ELDIM Co.) was used in front of the spherical coordinate system (0°, 0°), the luminance values were measured in each of the white mode and the black mode. Relative luminance was calculated as (luminance value in Example and Comparative Example/luminance value in Comparative Example 1) x 100. Roughness was measured by a method using EZCONTRAST X88RC (EZXL-176R-F422A4, ELDIM).

(2) Relative contrast ratio (unit: %): Spherical coordinate system (0°, 0°), (0°, 60°), (45°, 60°), and (90°, 60°), the ratio of the luminance value of the white mode to the luminance value of the black mode was calculated. The contrast ratio was calculated as (ratio of luminance value in white mode/luminance value in black mode) x 100 in the corresponding spherical coordinate system. The relative contrast ratio was calculated as (contrast ratio in Examples and Comparative Examples/contrast ratio in Comparative Example 1) x 100.

(3) Contrast ratio of the side to the front: The spherical coordinate system (0°, 30°), (0°, 60 °), the (0°, 30°) value of the white mode is [luminance value at (0°, 30°)]/[luminance value at (0°, 0°)] The lateral contrast ratio was calculated, and the (0°, 60°) value of the white mode was [luminance value at (0°, 60°)]/[luminance value at (0°, 0°)] The contrast ratio was calculated.

(4) 1/2 viewing angle (unit: °): When the contrast ratio was measured for each angle in (2), the 1/2 viewing angle was obtained as a value that showed 1/2 of the contrast ratio from the front.

(5) white mode color shift (Δxy, @30°): xy color values on the CIE 1931 color coordinates were measured for the sides (0°, 30°) of the spherical coordinate system. The white mode color shift was calculated as the difference (Δxy) between the front (0°, 0°) xy color values and the side (0°, 30°) xy color values.

(6) Rainbow Mura: After placing two kinds of fluorescent lamps on the top of the polarizer on the viewer side of the manufactured liquid crystal display module and turning on the fluorescent lamps, it was visually evaluated whether or not rainbow mura was generated on the screen on the side of the polarizer on the viewer side. A score of ◎ was given when there was almost no rainbow, △ when there was a little rainbow, and ⅹ when there was a lot of rainbow.

Example comparative example One 2 3 One 2 3 white mode relative luminance 91 92 90 100 94 89 illuminance 650.9 653.4 652.4 674 670.7 634.3 black mode relative luminance 138 135 141 100 132 127 illuminance 1.49 1.52 1.51 1.608 1.567 1.409 relative contrast ratio (0°,0°) 66 68 64 100 71 70 (0°,60°) 126 125 122 100 130 131 (45°,60°) 132 134 135 100 140 137 (90°,60°) 88 89 87 100 87 90 Side to front contrast ratio (0°,30°) 58 59 59 49 57 58 (0°,60°) 20 21 21 16 16 15 1/2 viewing angle Right and left 70.4 72.1 71.5 59.1 69.6 68.7 up and down 56.8 57.0 57.4 57.0 56.7 57 white mode color shift Right and left 0.017 0.018 0.015 0.015 0.019 0.017 up and down 0.014 0.013 0.011 0.013 0.013 0.013 Rainbow ◎ ◎ ◎ ⅹ △ △

As shown in Table 2, the polarizer of the present invention improved the viewing angle and contrast ratio in all directions including the front and side, and also improved the rainbow. As shown in (A) of FIG. 4, it can be confirmed that the polarizing plate of the present invention did not visually recognize a rainbow at all.

On the other hand, in Comparative Example 1 not including the first optical pattern unit, the second optical pattern unit, and the filling unit of the present invention and Comparative Example 2 not including the second optical pattern unit, the rainbow improvement in Example 3 was weak or the rainbow improvement was weak. was severe. As shown in (B) and (C) of FIG. 4 , the polarizers of Comparative Examples 1 and 2 had a severe rainbow.

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 (20)

A polarizer, a first optical pattern part laminated on an upper surface of the polarizer, a second optical pattern part laminated on an upper surface of the first optical pattern part, and filling between the first optical pattern part and the second optical pattern part Including a filling part,
The first optical pattern unit includes a first optical pattern, the first optical patterns are spaced apart from each other and are formed to protrude from an upper surface of the first optical pattern unit,
The second optical pattern part has a second optical pattern formed on a lower surface,
The first optical pattern, the filling part, and the second optical pattern satisfy Equation 1 and Equation 2 below, a polarizing plate:
[Equation 1]
R1 > R2
(In Equation 1, R1 is the refractive index of the second optical pattern, R2 is the refractive index of the first optical pattern)
[Equation 2]
R3 > R2
(In Equation 2, R3 is the refractive index of the filling part, R2 is the refractive index of the first optical pattern).
The polarizing plate of claim 1, wherein the second optical pattern part includes a base portion and the second optical pattern formed on a lower surface of the base portion, and the base portion satisfies Equations 4 and 5 below:
[Equation 4]
R1 ≥ R4
(In Equation 4, R1 is the refractive index of the second optical pattern, R4 is the refractive index of the base)
[Equation 5]
R3 ≥ R4
(In Equation 5, R3 is the refractive index of the filling part, R4 is the refractive index of the base part).
The polarizing plate according to claim 1, wherein the second optical pattern is an optical pattern having at least a curved surface.
The polarizing plate of claim 1, wherein the second optical pattern includes at least one of a microlens pattern, an embossing pattern, a lenticular lens pattern, and an embossing pattern.
The polarizing plate of claim 1 , wherein a maximum width of the second optical pattern is smaller than a period of the first optical pattern part and larger than a width of a first surface formed at an upper portion of the first optical pattern.
The polarizing plate of claim 1, wherein the maximum width of the second optical pattern is less than four times the period of the first optical pattern part.
The polarizing plate of claim 1 , wherein the second optical patterns are not spaced apart from each other.
The polarizing plate of claim 2, wherein an absolute value of a difference between a refractive index of the base part and a refractive index of the first optical pattern part is 0 to 0.5.
The polarizing plate of claim 1, wherein an absolute value of a difference between the refractive index of the second optical pattern and the refractive index of the filling part is 0 to 0.1.
The polarizing plate of claim 1 , wherein the second optical pattern and the filling part are integrally formed.
The polarizing plate of claim 1, wherein an upper surface of the second optical pattern part is flat.
The polarizing plate of claim 1, wherein the first optical pattern part satisfies Equation 3 below, and the first optical pattern has a base angle of 75° to 90°:
[Equation 3]
1 < P2/W2 ≤ 10
(In Equation 3, P2 is the period of the first optical pattern unit (unit: μm),
W2 is the maximum width of the first optical pattern (unit: µm).
The polarizing plate according to claim 1, wherein the first optical pattern is a pattern having a trapezoidal, square or rectangular cross section.
The polarizing plate of claim 1, wherein the first optical pattern part is non-adhesive or adhesive.
The polarizing plate of claim 1 , wherein a maximum thickness of the first optical pattern part is equal to or greater than a maximum height of the second optical pattern part.
The polarizing plate of claim 1 , wherein in the filling part, a minimum distance between the first optical pattern and the second optical pattern part is in a range of 0 μm to 15 μm.
The polarizing plate according to claim 1, wherein the second optical pattern is an intaglio optical pattern or an embossed optical pattern.
The polarizing plate of claim 1, wherein a protective layer is further formed on an upper surface of the second optical pattern unit.
The polarizing plate of claim 18 , wherein the protective layer is further formed with a surface treatment layer.
A liquid crystal display device comprising the polarizing plate of any one of claims 1 to 19.

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