KR102530187B1 - Polarizing plate and display device comprising the same - Google Patents

Abstract

A polarizing plate laminate according to an exemplary embodiment of the present application includes a polarizer; An adhesive layer or adhesive layer provided on the polarizer; a viewing angle compensation film provided on the pressure-sensitive adhesive layer or the adhesive layer; and a base film provided on the viewing angle compensation film.

Description

Polarizing plate laminate and display device including the same {POLARIZING PLATE AND DISPLAY DEVICE COMPRISING THE SAME}

The present application relates to a polarizing plate laminate and a display device including the same.

Liquid crystal display devices are widely used from mobile phones and portable small electronic devices to large electronic devices such as personal computers and televisions, and their uses are one of the flat panel displays that are gradually expanding.

As the use of the display device expands, the place where the display device is placed and its location are diversified. However, the flat panel display has a problem in that a clear image cannot be obtained when viewed from a direction other than the front of the display. In particular, in the case of a vehicle display, since the position of the display and the driver's line of sight are not parallel, there is a problem in that a clear image cannot be obtained from the driver's field of view.

Therefore, in order to solve this problem, development of a display device capable of improving a viewing angle and a contrast ratio is required.

Republic of Korea Patent Registration No. 10-1210985

The present application is intended to provide a polarizing plate laminate and a display device including the same.

In one embodiment of the present application,

polarizer;

An adhesive layer or adhesive layer provided on the polarizer;

a viewing angle compensation film provided on the pressure-sensitive adhesive layer or the adhesive layer; and

A polarizing plate laminate including a base film provided on the viewing angle compensation film,

The viewing angle compensation film includes a pattern layer and a planarization layer, and a difference in refractive index between the pattern layer and the planarization layer is 0.02 to 0.4,

The pattern layer may include a first surface including a flat surface; And a second surface facing the first surface and including a plurality of protrusions,

Each of the protrusions includes a first inclined surface and a second inclined surface,

An angle (θ ₁ ) between the first inclined surface or a surface extending the first inclined surface and the first surface and an angle (θ ₂ ) formed between the second inclined surface or a surface extending the second inclined surface and the first surface are equal to each other. has an angle

The aspect ratio of each of the protrusions represented by Equation 1 below is greater than 1.5 and less than 3.0,

It provides a polarizing plate laminate in which a flat surface is provided between protrusions adjacent to each other.

[Equation 1]

Aspect ratio of protrusion = Height of protrusion / Pitch of protrusion

In addition, in another embodiment of the present application,

liquid crystal cell;

a first polarizing plate provided on the viewing side of the liquid crystal cell;

a second polarizing plate provided on a side opposite to the viewing side of the liquid crystal cell; and

Including a backlight unit provided on the opposite side of the surface facing the liquid crystal cell of the second polarizing plate,

It provides a display device in which the first polarizing plate or the second polarizing plate is the polarizing plate laminate.

A polarizing plate laminate according to an exemplary embodiment of the present application includes a viewing angle compensation film having an aspect ratio of greater than 1.5 and less than 3.0 and a flat surface provided between adjacent protrusions, thereby improving a contrast ratio and a viewing angle. It has a characteristic.

Accordingly, since the display device including the polarizer laminate according to an exemplary embodiment of the present application can improve the contrast ratio and improve the viewing angle, a clear image can be obtained in the driver's field of view when used as a display device for a vehicle. there is

1 and 2 are views schematically illustrating a polarizing plate laminate according to an exemplary embodiment of the present application.
3 is a diagram schematically illustrating a viewing angle compensation film according to an exemplary embodiment of the present application.
4 is a diagram schematically illustrating a pattern layer included in a viewing angle compensation film according to an exemplary embodiment of the present application.
5 is a diagram schematically illustrating heights and pitches of protrusions in an exemplary embodiment of the present application.
6 to 13 are diagrams schematically illustrating a display device according to an exemplary embodiment of the present application.

Hereinafter, preferred embodiments of the present application will be described. However, the embodiments of the present application may be modified in many different forms, and the scope of the present application is not limited to the embodiments described below. In addition, the embodiments of the present application are provided to explain the present invention in more detail to those skilled in the art.

A polarizer laminate according to an exemplary embodiment of the present application includes a polarizer; An adhesive layer or adhesive layer provided on the polarizer; a viewing angle compensation film provided on the pressure-sensitive adhesive layer or the adhesive layer; and a base film provided on the viewing angle compensation film, wherein the viewing angle compensation film includes a pattern layer and a planarization layer, a difference in refractive index between the pattern layer and the planarization layer is 0.02 to 0.4, and the pattern layer forms a flat surface. a first surface comprising; and a second surface facing the first surface and including a plurality of protrusions, each of the protrusions including a first inclined surface and a second inclined surface, the first inclined surface or a surface extending the first inclined surface and a second surface. The angle formed by the first surface (θ ₁ ) and the angle formed by the second inclined surface or the surface extending the second inclined surface and the first surface (θ ₂ ) have the same angle, and each of the protrusions represented by Equation 1 below The aspect ratio of is greater than 1.5 and less than 3.0, and a flat surface is provided between adjacent protrusions.

[Equation 1]

Aspect ratio of protrusion = Height of protrusion / Pitch of protrusion

In this application, the term "viewing side" means a surface or direction disposed to face the viewer when the polarizer is mounted on a display device such as a liquid crystal display. Conversely, "the side opposite to the viewing side" means a side or direction disposed to face the opposite side of the viewer, that is, the backlight unit, when the polarizer is mounted on a display device such as a liquid crystal display.

In this application, "extension" means lengthening while maintaining the slope of a straight line or plane.

In this application, "flat surface" means that the center line average roughness (Ra) is less than 0.1 μm.

In one embodiment of the present application, the height of the protrusion means a vertical distance between the lowest point of the protrusion and the highest point of the protrusion, and the height of the protrusion may be 5 μm to 100 μm or 10 μm to 30 μm. When the pitch of the protrusions is the same and the height of the protrusions is low, this is because the angle of the apex of the protrusions is increased. Therefore, in an exemplary embodiment of the present application, the height of the protrusion is preferably 5 μm to 100 μm, and more preferably 10 μm to 30 μm.

In one embodiment of the present application, the pitch of the protrusions means a distance between first inclined surfaces of adjacent protrusions based on the first surface, and the pitch of the protrusions may be 5 μm to 30 μm, and 10 μm to 100 μm. μm. When the pitch of the protrusions is out of the above range, it is not preferable because a moiré phenomenon may occur with the panel.

The height and pitch of the protrusions are schematically shown in FIG. 5 below.

In one embodiment of the present application, the aspect ratio of each of the protrusions represented by Equation 1 may be greater than 1.5 and less than 3.0, or may be 1.6 to 2.0. By satisfying the aspect ratio of the protrusion as described above, there is a feature that can improve the contrast ratio of the viewing angle compensation film and improve the viewing angle.

In one embodiment of the present application, a flat surface may be provided between the protrusions adjacent to each other, and the length of the flat surface provided between the protrusions adjacent to each other may be 3 μm or less, and may be greater than 0 and less than 1.5 μm. When the length of the flat surface provided between the protrusions adjacent to each other is out of the above-described numerical range, the front luminance may not be affected, but the contrast ratio of Area A may be reduced.

In one embodiment of the present application, the highest point of each of the protrusions may have a radius of curvature (R) of 1 μm or less, and may have a radius of curvature (R) of 0.5 μm to 1 μm. By satisfying the radius of curvature of the highest point of the protrusion, the contrast ratio of the viewing angle compensation film can be improved and the viewing angle can be improved.

In one embodiment of the present application, the plurality of protrusions included in the second surface may be continuously arranged. When the plurality of protrusions are continuously provided, a pattern layer may be formed such that a first inclined surface of one protrusion and a second inclined surface of another protrusion come into contact with each other.

According to another exemplary embodiment, the plurality of protrusions may be provided in a non-continuous manner.

In one embodiment of the present application, at least one cross section perpendicular to the first surface of the protrusion may have a triangular, quadrangular or pentagonal shape. However, the highest point or lowest point of the triangular, quadrangular or pentagonal shape has a radius of curvature (R) of 1 μm or less.

When at least one cross section perpendicular to the first surface of the protrusion has a triangular shape, one end of the first inclined surface is in contact with an end of the second inclined surface and the other end is in contact with the first surface, An end of the second inclined surface that does not come into contact with an end of the first inclined surface may be formed to come into contact with the first surface.

When at least one cross section perpendicular to the first surface of the protrusion has a rectangular shape, one end of the first inclined surface and one end of the second inclined surface are in contact with the first surface, and the other end of the first inclined surface and the second inclined surface are in contact with each other. 2 includes a third inclined surface formed to come into contact with the other end of the inclined surface, or one end of the first inclined surface is in contact with the first surface and the other end is formed to contact with the end of the second inclined surface, It includes an end of the second inclined surface that does not come into contact with the end and a third inclined surface formed to come into contact with the first surface.

When at least one cross-section perpendicular to the first surface of the protrusion has a pentagonal shape, a plurality of protrusions are continuously formed, the protrusion includes a first inclined surface and a second inclined surface, and the first inclined surface of one protruding part is formed. The end of the protrusion and the end of the second inclined surface of the adjacent protrusion abut each other, but are formed so as not to come into contact with the first surface.

In an exemplary embodiment of the present application, the angle (θ) formed between the first inclined surface or a surface extending the first inclined surface and the second inclined surface or a surface extending the second inclined surface may be 20° to 60°, and 30 It may be ° to 50 °, and may be 40 ° to 50 °. When the angle θ formed between the first inclined surface or the plane extending the first inclined surface and the second inclined surface or the plane extending the second inclined surface satisfies the above range, the light incident on the viewing angle compensation film forms a condensing shape. By adjusting the angle of refraction, an effect of adjusting the viewing angle of the display device and improving the contrast ratio can be obtained.

In an exemplary embodiment of the present application, an angle θ ₁ formed between the first inclined surface or a surface extending the first inclined surface and the first surface and the second inclined surface or a surface extending the second inclined surface and the first surface are The formed angles θ ₂ have the same angle as each other. As θ ₁ and θ ₂ have different values, the angle of refraction of light incident on the pattern layer is adjusted, thereby improving the viewing angle and contrast ratio. At this time, the θ ₁ and θ ₂ may be 60° to 80°, or 70° to 80°.

In one embodiment of the present application, the planarization layer is provided on the second surface side of the pattern layer.

In another exemplary embodiment, the planarization layer is provided to contact the second surface of the pattern layer.

A difference in refractive index between the pattern layer and the planarization layer may be 0.02 to 0.4, preferably 0.03 to 0.2. In this case, the refractive index of the higher refractive index of the pattern layer and the planarization layer may be about 1.45 to 1.7, and the refractive index of the lower refractive index of the pattern layer and the planarization layer may be 1.3 to 1.55. The refractive index is measured at a wavelength of 590 nm.

The material of the pattern layer may be an ultraviolet curable resin, but is not limited thereto. As an example of the ultraviolet curable resin, epoxy (meth) acrylate, urethane (meth) acrylate, phenylphenol ethoxylated (meth) acrylate, trimethylolpropane ethoxylated (meth) acrylate, phenoxy Benzyl(meth)acrylate, phenylphenoxyethyl(meth)acrylate, ethoxylated thiodiphenyldi(meth)acrylate, phenylthioethyl(meth)acrylate monomers or oligomers thereof, or fluorene derivatives unsaturated It may include a resin, but is not limited thereto.

The material of the planarization layer may be formed using an ultraviolet curable resin or an acrylate-based adhesive.

The planarization layer may have a thickness of about 1 μm to about 200 μm.

A refraction angle of light passing through the pattern layer of the viewing angle compensation film may be 1° to 20°. According to another exemplary embodiment, it may be 3° to 15°.

In one embodiment of the present application, the base film is polyester, polyacrylic, polyvinyl chloride, polycarbonate, polymethyl methacrylate, polystyrene, polyester sulfone, polybutadiene, triacetate cellulose film (TAC), cyclo It may be an olefin polymer (COP), polyethylene terephthalate (PET), an acrylic film, etc., but is not limited thereto.

The acrylic film may include a (meth)acrylate-based resin, and the film containing the (meth)acrylate-based resin is formed by extrusion molding a molding material containing the (meth)acrylate-based resin as a main component. can be obtained

The acrylic film is a film comprising a copolymer containing an alkyl (meth)acrylate-based unit and a styrene-based unit and an aromatic resin having a carbonate moiety in the main chain, or an alkyl (meth)acrylate-based unit, a styrene-based unit, at least It may be a film comprising a 3- to 6-membered heterocyclic unit substituted with one carbonyl group and a vinyl cyanide unit. In addition, it may be an acrylic resin having a lactone structure.

As the (meth)acrylate-based resin having an aromatic ring, (a) a (meth)acrylate-based unit containing one or more (meth)acrylate-based derivatives; (b) a chain having a hydroxy group-containing part and an aromatic unit having an aromatic part; and (c) a resin composition containing a styrene-based unit containing at least one styrene-based derivative. Each of the units (a) to (c) may be included in the resin composition in the form of a separate copolymer, and two or more of the units (a) to (c) may be included in the resin composition in the form of a copolymer. there is.

The method for producing the (meth)acrylate-based resin film is not particularly limited, and for example, a thermoplastic resin composition is prepared by sufficiently mixing the (meth)acrylate-based resin and other polymers, additives, etc. by any suitable mixing method. After manufacturing, it may be manufactured by forming a film, or (meth)acrylate-based resin and other polymers, additives, etc. may be prepared as a separate solution and then mixed to form a uniform mixed solution, which may be formed into a film.

The thermoplastic resin composition is prepared by extruding and kneading the resulting mixture after pre-blending the film raw material with an arbitrary appropriate mixer such as an omni mixer. In this case, the mixer used for extrusion and kneading is not particularly limited, and any suitable mixer such as an extruder such as a single screw extruder or a twin screw extruder or a pressure kneader can be used.

The method of forming the film includes any suitable film forming method such as a solution casting method (solution casting method), a melt extrusion method, a calendar method, a compression molding method, etc., but is not limited thereto, but a solution casting method (solution casting method) , the melt extrusion method is preferred.

The solvent used in the solution casting method (solution casting method) includes, for example, aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as cyclohexane and decalin; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; alcohols such as methanol, ethanol, isopropanol, butanol, isobutanol, methyl cellosolve, ethyl cellosolve, and butyl cellosolve; ethers such as tetrahydrofuran and dioxane; halogenated hydrocarbons such as dichloromethane, chloroform, and carbon tetrachloride; dimethylformamide; Dimethyl sulfoxide etc. are mentioned, These solvent may be used independently or may use 2 or more types together.

Examples of the apparatus for performing the solution casting method (solution casting method) include a drum type casting machine, a band type casting machine, and a spin coater. Examples of the melt extrusion method include a T die method and an inflation method. The molding temperature is specifically 150 °C to 350 °C, more specifically 200 °C to 300 °C, but is not limited thereto.

In the case of forming a film by the T-die method, a roll-shaped film can be obtained by attaching a T-die to the tip of a known single-screw extruder or twin-screw extruder and winding the extruded film into a film shape. At this time, uniaxial stretching may also be performed by appropriately adjusting the temperature of the take-up roll and applying stretching in the extrusion direction. Moreover, simultaneous biaxial stretching, sequential biaxial stretching, etc. can also be performed by extending|stretching a film in the direction perpendicular|vertical to the extrusion direction.

The acrylic film may be either an unstretched film or a stretched film. In the case of a stretched film, it may be a uniaxially stretched film or a biaxially stretched film, and in the case of a biaxially stretched film, it may be either a simultaneous biaxially stretched film or a sequential biaxially stretched film. In the case of biaxial stretching, the mechanical strength is improved and the film performance is improved. By mixing other thermoplastic resins, the acrylic film can suppress increase in retardation and maintain optical isotropy even when stretched.

The stretching temperature is preferably in the range of the glass transition temperature of the thermoplastic resin composition as a film raw material, preferably in the range of (glass transition temperature - 30 ° C.) to (glass transition temperature + 100 ° C.), more preferably (glass transition temperature + 100 ° C.) It is within the range of transition temperature - 20 ℃) to (glass transition temperature + 80 ℃). If the stretching temperature is less than (glass transition temperature - 30°C), there is a possibility that a sufficient stretching ratio may not be obtained. Conversely, if the stretching temperature exceeds (glass transition temperature + 100°C), flow of the resin composition may occur and stable stretching may not be performed.

The draw ratio defined by the area ratio is preferably 1.1 to 25 times, more preferably 1.3 to 10 times. If the stretching ratio is less than 1.1 times, there is a possibility that the improvement in toughness accompanying stretching may not be achieved. When the draw ratio exceeds 25 times, there is a possibility that the effect of increasing the draw ratio may not be recognized.

The stretching speed in one direction is preferably 10%/min to 20,000%/min, more preferably 100%/min to 10,000%/min. When the stretching speed is less than 10%/min, it takes a rather long time to obtain a sufficient stretching ratio, which may increase manufacturing cost. If the stretching speed exceeds 20,000%/min, there is a possibility that the stretched film may be broken or the like.

In order to stabilize the optical isotropy or mechanical properties of the acrylic film, heat treatment (annealing) or the like may be performed after the stretching treatment. Heat treatment conditions are not particularly limited and any appropriate conditions known in the art can be employed.

In one embodiment of the present application, an optical layer may be further included on a surface opposite to the surface of the base film on which the viewing angle compensation film is provided. The optical layer may include one or more of an anti-glare layer (AG), a hard coating layer (HC), a low refractive index layer (LR), an anti-glare & low-reflection (AGLR), an anti-reflection layer (AR), and the like, Not limited to this. At this time, using a coating composition for forming the layers, a method well known in the art, for example, a bar coating method, a gravure coating method, a slot die coating method, etc., to describe the coating composition It may be performed by a method of applying on a film and drying. At this time, the drying may be performed through a convention oven or the like, but is not limited thereto, and is preferably performed at a temperature of 100° C. to 120° C. for 1 minute to 5 minutes. The drying temperature varies depending on the coating step, and in the case of a stretched film, it can be performed within a range that does not exceed the glass transition temperature (Tg) of the film. It is carried out in a range that does not exceed the decomposition temperature (Td) of.

The hard coating layer, the antiglare layer (AG), the low refractive index layer (LR), the AGLR (Anti-Glare &Low-Reflection) and the antireflection layer (AR) may be formed of a general-purpose primer layer material, the hard coating layer, Each of the antiglare layer (AG), low refractive index layer (LR), anti-glare & low-reflection (AGLR), or antireflection layer (AR) layer may have a thickness of 1 μm to 100 μm.

In one embodiment of the present application, the polarizer and the adhesive layer may be provided in direct contact.

In one embodiment of the present application, a polarizer protective film may be further included between the polarizer and the pressure-sensitive adhesive layer. The polarizer protective film may be a triacetate cellulose film (TAC), a cycloolefin polymer (COP), an acrylic film, and the like, but is not limited thereto.

In one embodiment of the present application, the polarizer is not particularly limited, and a polarizer well known in the art, for example, a film made of polyvinyl alcohol (PVA) containing iodine or a dichroic dye may be used. .

A polarizer exhibits a characteristic capable of extracting only light vibrating in one direction from incident light vibrating in several directions. These properties can be achieved by stretching poly vinyl alcohol (PVA) with iodine absorption with strong tension. For example, more specifically, the step of swelling the PVA film by soaking it in an aqueous solution, dyeing the swollen PVA film with a dichroic material that imparts polarization, and stretching the dyed PVA film ) to form a polarizer through a stretching step of arranging the dichroic dye material side by side in the stretching direction, and a complementary color step of correcting the color of the PVA film that has passed through the stretching step. However, the polarizing plate of the present application is not limited thereto.

In one embodiment of the present application, the pressure-sensitive adhesive layer or adhesive layer may include a general-purpose pressure-sensitive adhesive or adhesive, and the thickness of the pressure-sensitive adhesive layer or adhesive layer may be 1 μm to 200 μm, and 1 μm to 100 μm. It may be, but is not limited thereto.

A polarizing plate laminate according to an exemplary embodiment of the present application is schematically shown in FIGS. 1 and 2 below. As shown in FIG. 1 below, a polarizing plate laminate according to an exemplary embodiment of the present application includes a polarizer 10; An adhesive layer or adhesive layer 20 provided on the polarizer 10; a viewing angle compensation film 30 provided on the pressure-sensitive adhesive layer or the adhesive layer 20; and a base film 40 provided on the viewing angle compensation film 30 . In addition, as shown in FIG. 2 below, the polarizing plate laminate according to an exemplary embodiment of the present application further includes an optical layer 50 on the opposite side of the base film 40 on which the viewing angle compensation film 30 is provided. can do.

In addition, a pattern layer included in the viewing angle compensation film according to an exemplary embodiment of the present application is schematically shown in FIG. 4 below.

In addition, another exemplary embodiment of the present application is a liquid crystal cell; a first polarizing plate provided on the viewing side of the liquid crystal cell; a second polarizing plate provided on a side opposite to the viewing side of the liquid crystal cell; and a backlight unit provided on a side opposite to a surface of the second polarizing plate facing the liquid crystal cell, wherein the first polarizing plate or the second polarizing plate is a laminate of the polarizing plates.

In one embodiment of the present application, the display device may be manufactured using materials and methods known in the art, except that the first polarizing plate or the second polarizing plate is the polarizing plate laminate.

In one embodiment of the present application, the second surface of the pattern layer may be disposed close to the liquid crystal cell.

In one embodiment of the present application, the display device may be a vehicle display device.

A display device including a polarizing plate laminate according to an exemplary embodiment of the present application is schematically shown in FIGS. 6 to 13 below.

According to an exemplary embodiment of the present application, as the main viewing angle (maximum brightness angle) of the display device changes and the light concentration increases, the contrast ratio (C/R) at a position not parallel to the display device increases. can be improved

The backlight unit includes a light source for irradiating light from the rear surface of the liquid crystal panel, and the type of the light source is not particularly limited, and a general LCD light source such as CCFL, HCFL, or LED may be used.

Hereinafter, exemplary embodiments described in this specification are illustrated through examples. However, it is not intended that the scope of the embodiments be limited by the following examples.

< Example >

< manufacturing example 1> A viewing angle compensation film with an aspect ratio of 1.87 and a flat surface length of 0.5 μm

As shown in FIG. 3, a viewing angle compensation film was formed by stacking the base film 40/pattern layer 90/flattening layer 100 in this order.

1) Pattern layer: the angle (θ) formed by the first inclined surface and the second inclined surface is 30 °, the angle (θ ₁ ) formed by the first inclined surface and the first surface is 75 °, and the second inclined surface is formed with the first surface Angle (θ ₂ ) is 75° (refractive index at a wavelength of 590 nm: 1.43)

The height of the protrusions of the pattern layer is 28 μm, the pitch of the protrusions is 15 μm, and the aspect ratio of the protrusions is 1.87.

The length of the flat surface between the protrusions adjacent to each other is 0.5 μm.

2) Planarization layer: provided on top of the pattern layer (refractive index at a wavelength of 590 nm: 1.61)

< manufacturing example 2> A viewing angle compensation film with an aspect ratio of 1.87 and a flat surface length of 1 μm

In Preparation Example 1, the configuration was the same as in Preparation Example 1, except that the length of the flat surface between the protrusions adjacent to each other of the pattern layer was adjusted to 1 μm.

< manufacturing example 3> A viewing angle compensation film with an aspect ratio of 1.87 and a flat surface length of 1.5 μm

In Preparation Example 1, the configuration was the same as in Preparation Example 1 except that the length of the flat surface between the protrusions adjacent to each other of the pattern layer was adjusted to 1.5 μm.

< manufacturing example 4> A viewing angle compensation film with an aspect ratio of 1.87 and a flat surface length of 2 μm

In Preparation Example 1, the configuration was the same as in Preparation Example 1, except that the length of the flat surface between the protrusions adjacent to each other of the pattern layer was adjusted to 2 μm.

< manufacturing example 5> A viewing angle compensation film with an aspect ratio of 1.87 and a flat surface length of 2.5 μm

In Preparation Example 1, the configuration was the same as in Preparation Example 1, except that the length of the flat surface between the protrusions adjacent to each other of the pattern layer was adjusted to 2.5 μm.

< manufacturing example 6> A viewing angle compensation film with an aspect ratio of 1.87 and a flat surface length of 3 μm

In Preparation Example 1, the configuration was the same as in Preparation Example 1, except that the length of the flat surface between the protrusions adjacent to each other of the pattern layer was adjusted to 3 μm.

< manufacturing example 7> A viewing angle compensation film with an aspect ratio of 1.87 and a flat surface length of 3.5 μm

The configuration was the same as in Preparation Example 1 except that the length of the flat surface between the protrusions adjacent to each other of the pattern layer in Preparation Example 1 was adjusted to 3.5 μm.

< manufacturing example 8> aspect ratio 1.87, flat surface length 1㎛, index of refraction Viewing angle compensation film with a difference of 0.13

The configuration was the same as in Preparation Example 2 except that the difference in refractive index between the pattern layer and the planarization layer was adjusted to 0.13 in Preparation Example 2.

(pattern layer refractive index 1.45 / flat layer refractive index 1.58)

< manufacturing example 9> aspect ratio 1.87, peak radius of curvature 0.5㎛, flat surface length 1㎛ viewing angle compensation film

In Preparation Example 2, the configuration was the same as in Preparation Example 1, except that a radius of curvature (R) of 0.5 μm was introduced at the highest point of each protrusion of the pattern layer.

< manufacturing example 10> aspect ratio 1.87, peak radius of curvature 0.5㎛, flat surface length 1㎛ viewing angle compensation film

In Preparation Example 9, the configuration was the same as in Preparation Example 9, except that the difference in refractive index between the pattern layer and the planarization layer was adjusted to 0.11.

(pattern layer refractive index 1.50 / flat layer refractive index 1.61)

< Comparative Manufacturing Example 1> Aspect ratio 1.07, flat surface length 1㎛, index of refraction Viewing angle compensation film with a difference of 0.13

In Preparation Example 8, the configuration was the same as in Preparation Example 8 except that the aspect ratio of the protrusion was adjusted to 1.07 by configuring the pattern layer as follows.

1) Pattern layer: the angle (θ) formed by the first inclined surface and the second inclined surface is 50 °, the angle (θ ₁ ) formed by the first inclined surface and the first surface is 65 °, and the second inclined surface is formed with the first surface Angle (θ ₂ ) is 65° (refractive index at a wavelength of 590 nm: 1.45)

The height of the protrusions of the pattern layer is 16.1 μm, the pitch of the protrusions is 15 μm, and the aspect ratio of the protrusions is 1.07.

< Comparative Manufacturing Example 2> Aspect ratio 1.37, flat surface length 1㎛, index of refraction Viewing angle compensation film with a difference of 0.13

In Preparation Example 8, the simulation was conducted with the same configuration as in Preparation Example 8, except that the aspect ratio of the protrusion was adjusted to 1.07 by configuring the pattern layer as follows.

1) Pattern layer: The angle (θ) formed by the first inclined surface and the second inclined surface is 40 °, the angle (θ ₁ ) formed by the first inclined surface and the first surface is 70 °, and the second inclined surface is formed with the first surface Angle (θ ₂ ) is 70° (refractive index at a wavelength of 590 nm: 1.45)

The height of the protrusions of the pattern layer is 20.6 μm, the pitch of the protrusions is 15 μm, and the aspect ratio of the protrusions is 1.37.

< Example 1>

A simulation was performed by configuring a display device including the viewing angle compensation film of the above Preparation Example and Comparative Production Example.

A polarizing plate was prepared by laminating the viewing angle compensation film to a pre-prepared polarizer. Specifically, an adhesive was applied to the second surface side of the pattern layer of the viewing angle compensation film of Preparation Example 1, and the viewing angle compensation film was laminated on one side of the polarizer through this to form a polarizing plate laminate.

As a second polarizing plate provided on the opposite side of the viewing side of the liquid crystal cell, the polarizing plate laminate was disposed to construct a display device.

Contrast Ratio (C/R) distribution of the display device was measured, and the results are shown in Table 1 below. The CR value was calculated by measuring the viewing angle distribution in the on/off state (White/Black mode) of the panel using EZContrast xl88 equipment from Eldim.

Liquid crystal displays (LCDs) are used in various devices such as TVs, monitors, mobile phones, and tablet PCs. A liquid crystal display device is a numerical value representing performance, and its performance is expressed using a value called CR (contrast ratio), which represents the ratio of white front luminance (On state) and black front luminance (Off state), and the CR is The higher the value, the better the device was evaluated.

However, for technological development and human convenience, liquid crystal displays have begun to be applied to fields that have not previously been applied, and liquid crystal displays for automobiles, such as automobile dashboards and navigation systems, have been introduced. In the case of such liquid crystal display devices for automobiles, in most cases, the screen is viewed from the side rather than from the front, like conventional liquid crystal display devices (TVs, mobile phones, etc.). Accordingly, in the present application, a numerical value called Area A CR, which quantifies the performance at a viewing angle, was introduced in addition to the front CR indicating the performance of the liquid crystal display. In this application, the Area A CR indicates CR at a viewing angle of 40 degrees.

< Example 2~10>

Example 1 was performed in the same manner as in Example 1, except that the viewing angle compensation films of Preparation Examples 2 to 10 were applied instead of the viewing angle compensation film of Preparation Example 1.

< comparative example 1>

As a reference, a display device without a viewing angle compensation film was constructed.

< comparative example 2~3>

Example 1 was performed in the same manner as in Example 1, except that the viewing angle compensation film of Comparative Preparation Examples 1 and 2 was applied instead of the viewing angle compensation film of Preparation Example 1.

[Table 1]

As shown in Table 1, when the aspect ratio of each protrusion is greater than 1.5 and less than 3.0 at a refractive index difference of 0.18, and a viewing angle compensation film provided with a flat surface is applied between adjacent protrusions, there is no significant difference in frontal brightness. However, it can be confirmed that the luminance of Area A increases. In addition, when the length of the flat surface provided between the protrusions adjacent to each other is 3 μm or less, it is more preferable in terms of the improvement of the contrast ratio of Area A.

[Table 2]

As shown in Table 2, it can be confirmed that frontal brightness and Area A luminance increase when a viewing angle compensation film having an aspect ratio of more than 1.5 and less than 3.0 is applied.

[Table 3]

As shown in Table 3, in the case of applying a viewing angle compensation film having a curvature radius (R) of 1 μm or less at the highest point of each protrusion and having a flat surface between adjacent protrusions, the front brightness is slightly reduced. However, it can be confirmed that the luminance of Area A increases.

As a result, the polarizing plate laminate according to an exemplary embodiment of the present application includes a viewing angle compensation film having an aspect ratio of greater than 1.5 and less than 3.0 and a flat surface provided between adjacent protrusions, thereby improving the contrast ratio and improving the viewing angle. There are features that can be improved.

Accordingly, since the display device including the polarizer laminate according to an exemplary embodiment of the present application can improve the contrast ratio and improve the viewing angle, a clear image can be obtained in the driver's field of view when used as a display device for a vehicle. there is

10: polarizer
20: adhesive layer or adhesive layer
30: viewing angle compensation film
40: base film
50: optical layer
60: polarizer protective film
70: liquid crystal cell
80: LC (liquid crystal)
90: pattern layer
100: planarization layer
110: first surface of the pattern layer
120: second surface of the pattern layer
130: highest point of protrusion
140: lowest point of protrusion
150: height of protrusion
160: Pitch of projections
170: flat surface between protrusions adjacent to each other

Claims (13)

liquid crystal cell;
a first polarizing plate provided on the viewing side of the liquid crystal cell;
a second polarizing plate provided on a side opposite to the viewing side of the liquid crystal cell; and
A display device including a backlight unit provided on the opposite side of the surface facing the liquid crystal cell of the second polarizing plate,
The second polarizing plate may include a polarizer; An adhesive layer or adhesive layer provided on the polarizer; a viewing angle compensation film provided on the pressure-sensitive adhesive layer or the adhesive layer; And a polarizing plate laminate comprising a base film provided on the viewing angle compensation film,
The viewing angle compensation film includes a pattern layer and a planarization layer, and a difference in refractive index between the pattern layer and the planarization layer is 0.02 to 0.4,
The pattern layer may include a first surface including a flat surface; And a second surface facing the first surface and including a plurality of protrusions,
Each of the protrusions includes a first inclined surface and a second inclined surface,
An angle (θ ₁ ) between the first inclined surface or a surface extending the first inclined surface and the first surface and an angle (θ ₂ ) formed between the second inclined surface or a surface extending the second inclined surface and the first surface are equal to each other. has an angle
The angle θ formed between the first inclined surface or a surface extending the first inclined surface and the second inclined surface or a surface extending the second inclined surface is 20 ° to 60 °,
The highest point of each of the protrusions has a radius of curvature (R) of 0.5 μm to 1 μm,
The aspect ratio of each of the protrusions represented by Equation 1 below is greater than 1.5 and less than 3.0,
A display device wherein a flat surface is provided between protrusions adjacent to each other:
[Equation 1]
Aspect ratio of protrusion = Height of protrusion / Pitch of protrusion The display device according to claim 1, wherein the polarizer and the adhesive layer are provided in direct contact with each other. The display device according to claim 1, further comprising a polarizer protective film between the polarizer and the pressure-sensitive adhesive layer. The display device according to claim 1, further comprising an optical layer on a surface opposite to the surface of the base film on which the viewing angle compensation film is provided. The method according to claim 4, wherein the optical layer includes at least one of an anti-glare layer (AG), a hard coating layer (HC), a low refractive index layer (LR), an anti-glare & low-reflection (AGLR), and an anti-reflection layer (AR) A display device that does. The display device according to claim 1 , wherein the length of the flat surfaces provided between the protrusions adjacent to each other is 3 μm or less. The display device according to claim 1, wherein the protrusion has a height of 5 μm to 100 μm. The display device according to claim 1 , wherein a pitch of the protruding portions ranges from 5 μm to 30 μm. delete delete delete The display device according to claim 1, wherein the second surface of the pattern layer is disposed close to the liquid crystal cell. The display device according to claim 1, wherein the display device is a vehicle display device.

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