KR20150145139A - Depolarization film and manufacturing method of the same - Google Patents

Abstract

The present invention provides a depolarization film and an LCD device including the same. The depolarization film of the present invention includes: a film substrate; a particle layer which is formed on the substrate and includes depolarization particles; and an LCD layer which is formed on the surface of the particle layer and includes depolarization liquid crystal. The depolarization film presented in present invention have efficient depolarization effect and reduce haze.

Description

[0001] DEPOLARIZATION FILM AND MANUFACTURING METHOD OF THE SAME [0002]

The present invention relates to a depolarizing film and a manufacturing method thereof.

In recent years, the display field has been rapidly developed, and various flat panel display devices having excellent performance such as thinning, light weight, and low power consumption have been developed and replaced with existing CRT (cathode ray tube) .

Specific examples of such a flat panel display include a liquid crystal display (LCD), a plasma display panel (PDP), a field emission display (FED), an organic electroluminescent display Organic Electroluminescence Device).

Among them, the liquid crystal display device is one of the most widely used flat panel displays. In general, a liquid crystal display device has a structure in which a liquid crystal layer is sealed between a TFT (Thin Film Transistor) array substrate and a color filter substrate.

The polarizing plate is used in and out of the liquid crystal cell for the purpose of controlling the direction of light oscillation in order to visualize the display pattern of the liquid crystal display device. Application fields of liquid crystal display devices have been spreading from small-sized devices at the beginning of development to navigation systems for on-vehicle use and measurement devices used indoors and outdoors.

However, when the liquid crystal display device is viewed with the polarized sunglasses worn, there is a problem that it is difficult to properly view the screen of the liquid crystal display device due to the polarizer of the sunglasses and the polarizer of the liquid crystal display device.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a polarizing elimination film capable of effectively reducing polarizing loss and reducing haze, and to provide a manufacturing method of the polarizing elimination film.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method of manufacturing the same.

According to an aspect of the present invention, there is provided a polarizing elimination film comprising a base film, and a polarizer layer including a liquid crystal coated on the base film, wherein an angle at which the liquid crystal is oriented, Lt; RTI ID = 0.0 > 45 < / RTI >

The thickness of the depolarization layer may range from 1 탆 to 3 탆.

The haze of the depolarization film may be within 2%.

The base film may include a polarizing film.

The concentration range of the liquid crystal may be 5% to 30%.

The degree of depolarization of the depolarization film may be 20% or more.

According to an aspect of the present invention, there is provided a liquid crystal display device including a liquid crystal cell, a backlight unit, a lower polarizer disposed between the liquid crystal cell and the backlight unit, and a polarizing solution film.

The polarizing elimination film may be disposed on the viewer side of the liquid crystal cell.

The base film may be disposed between the depolarization layer and the liquid crystal cell.

According to another aspect of the present invention, there is provided a method of manufacturing a polarized light eliminating film, comprising the steps of moving a base film, coating liquid crystal on the base film to coat the polarizing layer, And moving the liquid between the rolls, wherein an angle at which the liquid crystal is oriented may be from -45 degrees to +45 degrees with respect to the machine direction of the base film.

The moving speed of the base film may range from 3 m / s to 20 m / s.

And UV curing the coated liquid crystal.

The step of coating the depolarization layer may be performed by a gravure coating, a dip coating, or a die coating method.

The details of other embodiments are included in the detailed description and drawings.

The embodiments of the present invention have at least the following effects.

The liquid crystal display device including the depolarizing film of the present invention can eliminate polarized light, reduce the haze value, and improve external visibility.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the specification.

1 is a perspective view schematically showing a depolarizing film according to an embodiment of the present invention.
Fig. 2 is a plan view showing an enlarged portion A of the depolarization film of Fig. 1. Fig.
3 is a cross-sectional view schematically showing a liquid crystal display device according to an embodiment of the present invention.
4 is a cross-sectional view schematically showing a liquid crystal cell of a liquid crystal display according to an embodiment of the present invention.
5 is a cross-sectional view schematically showing a liquid crystal display device according to another embodiment of the present invention.
Fig. 6 is an image of the polarization canceling layer of the embodiment.
Fig. 7 is an image of a polarizing resolution layer of a comparative example. Fig.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

It is to be understood that elements or layers are referred to as being "on " other elements or layers, including both intervening layers or other elements directly on or in between. Like reference numerals refer to like elements throughout the specification.

Although the first, second, etc. are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may be the second component within the technical scope of the present invention.

It should also be understood that the steps constituting the manufacturing method described herein may be sequential or sequential, or one step and the other step constituting one manufacturing method may be performed in the order described in the specification It is not construed as limited. Therefore, the order of the steps of the manufacturing method can be changed within a range that can be easily understood by a person skilled in the art, and a change apparent to a person skilled in the art accompanying thereto is included in the scope of the present invention.

Depolarization film

Hereinafter, a polarizing elimination film according to an embodiment of the present invention will be described with reference to Figs. 1 and 2. Fig. FIG. 1 is a perspective view schematically showing a polarizing elimination film according to an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view of a polarizing elimination film of FIG.

1 and 2, a depolarizing film 30 according to an embodiment of the present invention includes a base film 10 and a polarizing resolution layer 20 including a liquid crystal 21 coated on the base film 10 And the angle at which the liquid crystal 21 is oriented may be -45 degrees to +45 degrees with respect to the machine direction (MD) of the base film 10.

More specifically, the liquid crystal 21 may be coated on the base film 10 to form the polarization canceling layer 20, and the liquid crystal 21 may be formed on the base film 10 with respect to the machine direction MD An orientation angle of -45 DEG to + 45 DEG can be formed. 2, the liquid crystal 21 may have a shape including a long axis and a short axis, and the meaning of the angle at which the liquid crystal 21 is oriented is a direction in which the liquid crystal 21 21) is formed. 2, an angle? 1 formed on the upper side of the machine direction MD of the base film 10 can be -45 degrees with respect to the machine direction MD, and an angle? 2 formed below the machine direction MD It can be regarded as + 45 ° with respect to the machine direction (MD).

There is a problem that when the liquid crystal for forming the polarization canceling layer is formed in the random direction and is formed in a range of angles to form a domain, the haze value is increased. Here, the domain means that the liquid crystal partially forms a group in a specific range on the base film. For example, in the case where a plurality of domains are formed on a base film in which a liquid crystal is formed in a range of 360 degrees with respect to a specific point, a haze value of the depolarization film as a whole may increase due to such a domain have.

Therefore, as in the present invention, when the liquid crystal alignment angle range as in the present invention is satisfied on the base film, the haze value can be drastically lowered while performing the polarization canceling function.

The polarizing elimination film of the present invention is characterized in that it forms an alignment angle of the liquid crystal 21 in the range of -45 DEG to + 45 DEG with respect to the machine direction of the base film 10, It is possible to solve the polarization in the range of 45 DEG to + 45 DEG. When the polarizing elimination film is actually laminated to another film, the polarizing film is laminated only in a certain direction, and polarization elimination is not required in all directions substantially 360 DEG. Therefore, Can be effectively lowered.

On the other hand, the range of the orientation angle of the liquid crystal can be formed by applying a roll-to-roll coating as described below, and the roll-to-roll coating can be performed by, for example, gravure coating, (dip coating) or die coating (die coating). At this time, the range of the orientation angle of the liquid crystal with respect to the machine direction of the base film 10 can be appropriately adjusted by adjusting the moving speed of the base film 10. In addition, the thickness of the depolarization layer can be appropriately adjusted by properly changing the moving speed of the base film 10, the concentration of the liquid crystal 21, the roll application method according to the coating method, and the like.

In an exemplary embodiment, the thickness D1 of the depolarizing layer 20 may range from 1 m to 3 m, and the haze value of the depolarizing film 30 may be within 2%. When the thickness D1 of the polarization canceling layer 20 satisfies the above range, the haze value of the polarization canceling film 30 can be controlled within 2%. The haze value can be measured using NDH-5000 (Nippon Denshoku).

More specifically, as described above, by forming the alignment angle of the liquid crystal 21 in the range of -45 DEG to + 45 DEG with respect to the machine direction of the base film 10, And the haze value can be effectively reduced in the above range.

Any material capable of transmitting light can be used for the base film 10 without limitation. In the exemplary embodiment, the base film 10 may be optically in-plane isotropic, and may include, for example, a TAC film, a cycloolefin-based film, and the like. In another exemplary embodiment, the base film 10 may be optically anisotropic, in which case the optical axis of the base film 10 coincides with the absorption axis or transmission axis of the polarizer disposed on the viewing side of the display device Can be deployed. The optically anisotropic substrate film 10 is exemplified by a stretched film, but is not limited thereto.

In an exemplary embodiment, the base film 10 may comprise a polarizing film. In the case where the base film 10 is made of a polarizing film, the polarizing plate can be omitted when the polarizing elimination film is mounted on the liquid crystal display device to be described below, thereby making the liquid crystal display device thinner. When the base film 10 includes a polarizing film, the depolarizing layer 20 may be formed on a protective film (not shown) positioned on the viewer side of the polarizing film.

The concentration range of the liquid crystal 21 may be 5% to 30%. By controlling the concentration range of the liquid crystal 21 as described above, the thickness range of the polarization canceling layer 20 can be adjusted, and as a result, a polarization canceling layer capable of lowering the haze value can be formed while performing the polarization canceling function have.

On the other hand, the degree of depolarization of the depolarization film may be 20% or more, for example, 30% or more. Here, the degree of depolarization can be expressed by the following equation (1).

식(1)Polarization resolution (%) =

Equation (1)

A transmission that is transmitted when a TT [POL _↕↕] are arranged in parallel to the polarizer only in the formula (1), in the case of the TT [POL (↔) / Sample / POL (↕)] polarization is eliminated between the crossed-Nicol polarizing plates The transmittance of the film when it is placed. At this time, the transmittance can be measured using NDH-5000 (Nippon Denshoku).

The liquid crystal 21 can be used without limitation as far as it has birefringence. Among the known ones, those can be appropriately selected for use in the manufacturing process, etc., and commercially available ones can be generally used. The liquid crystal 21 is well known in the art, and a detailed description thereof will be omitted.

Liquid crystal display

FIG. 3 is a cross-sectional view schematically showing a liquid crystal display device according to an embodiment of the present invention, and FIG. 4 is a schematic cross-sectional view of a liquid crystal cell included in a liquid crystal display device.

3 and 4, the liquid crystal display includes a liquid crystal cell 200, a backlight unit 300, a lower polarizer 110 disposed between the liquid crystal cell 200 and the backlight unit 300, 30).

The polarizing elimination film 30 may be disposed on the viewing side of the liquid crystal cell 200 and the base film 10 may be disposed between the polarizing elimination layer 20 and the liquid crystal cell 200.

The liquid crystal cell 200 includes a liquid crystal panel including a first substrate 210, a second substrate 230, a liquid crystal layer 220 sealed between the first substrate 210 and the second substrate 230, , The polarization canceling film 30 may be laminated on one surface (upper surface) of the first substrate 210. The lower polarizer plate 110 may also be laminated on the lower surface of the second substrate 230.

The base film 10 of the depolarizing film 30 may be formed of a polarizing plate so that the lower polarizing plate 110 positioned below the liquid crystal cell 200 and the polarizing plate 10 positioned above the liquid crystal cell 200 ), The transmission axes of the polarizers of the respective polarizing plates may be orthogonal or parallel to each other.

The first substrate 210 may be a color filter (CF) substrate. A black matrix for preventing light leakage, a color filter for red, green, and blue, and a transparent conductive oxide such as ITO or IZO are formed on a lower surface of a substrate made of a transparent insulating material such as glass or plastic And a common electrode which is an electric field generating electrode formed.

The second substrate 230 may be a TFT (Thin Film Transistor) substrate. Though not specifically shown, for example, a thin film transistor composed of a gate electrode, a gate insulating film, a semiconductor layer, a resistive contact layer, and a source / drain electrode and a thin film transistor formed of a transparent insulating material such as ITO or IZO And a pixel electrode that is an electric field generating electrode formed of a transparent conductive oxide.

The plastic substrate that can be used for the first substrate 210 and the second substrate 230 may be a plastic substrate such as PET (polyethylene terephthalate), PC (polycarbonate), PI (polyimide), PEN (polyethylene naphthalate) sulfone, PAR (polyarylate), and COC (cycloolefin copolymer). However, the present invention is not limited thereto. Also, the first substrate 210 and the second substrate 230 may be made of a flexible material.

The liquid crystal layer 220 may be a twisted nematic (TN) mode having a positive dielectric constant anisotropy, a vertically aligned (VA) mode or a horizontally aligned (IPS, FFS) mode or the like. In FIG. 4, the TN mode is described as an example.

When there is no voltage difference between the pixel electrode and the common electrode, that is, the electric field generating electrode, the electric field is not applied to the liquid crystal layer 220. As shown in FIG. 4, the liquid crystal of the liquid crystal layer 220, And is arranged parallel to the surfaces of the substrate 210 and the second substrate 230 and has a structure in which the first substrate 210 and the second substrate 230 are spirally twisted by 90 °.

The polarized light of linearly polarized light passes through the liquid crystal layer 220 and changes due to retardation due to the refractive index anisotropy of the liquid crystal. When the dielectric anisotropy (DELTA epsilon) of the liquid crystal and the chiral pitch or the thickness of the liquid crystal layer 220, i.e., the cell gap, are adjusted, the linearly polarized light direction of the light passing through the liquid crystal layer 220 is 90 °.

The backlight unit 300 may generally include a light source, a light guide plate, a reflective film, and the like. Depending on the configuration of the backlight, it can be arbitrarily divided into a direct-down system, a sidelight system, and a planar light source system.

5 is a cross-sectional view schematically showing a liquid crystal display device according to another embodiment of the present invention.

5, the liquid crystal display device may further include an upper polarizer 120 disposed on the viewer side of the liquid crystal cell 200 of the liquid crystal display device, and two polarizers 110 and 120 may be disposed above and below the liquid crystal cell 200 When positioned, the polarizer and transmission axis of each polarizing plate may be orthogonal or parallel to each other.

Method for manufacturing depolarization film

A method of producing a depolarizing film may include a step of moving a base film, a step of coating a liquid crystal on the base film, and a step of moving the base film through a roll and a roll . Further, the angle at which the liquid crystal is oriented may be -45 deg. To + 45 deg. Relative to the machine direction of the base film.

More specifically, while moving the base film, the liquid crystal coating liquid may be coated on the base film using a gravure roll. When the liquid crystal is coated, the liquid crystal coated on the base film undergoes shear in the machine direction as the base film rapidly moves in the machine direction, so that the liquid crystal is aligned with the machine direction of the base film in the range of 45 deg. To be coated.

The method may further include fixing the coated liquid crystal by UV curing. By receiving a mechanical shear with respect to the machine direction in which the base film moves before the liquid crystal is UV-cured as described above, To 45 [deg.] To + 45 [deg.] Angular range.

More specifically, the term " machine direction " refers to a direction in which the base film is moved. The liquid crystal coating layer on the base film receives the shear at a high moving speed of the base film at the moving speed of the base film, May be oriented in the direction in which the base film proceeds, and the angle may be formed in the range of -45 DEG to + 45 DEG. The polarizing elimination film of the present invention can orient the liquid crystal formed in the polarization canceling layer to a specific angle range without using a separate liquid crystal alignment film and function to lower the polarization dissolving function and the haze value.

The moving speed of the base film may range from 3 m / s to 20 m / s. The dropping rate of the liquid crystal may be in the range of 5 m / s to 15 m / s. The angle at which the liquid crystal is oriented in the above range can be easily adjusted in the range of -45 DEG to + 45 DEG with respect to the machine direction of the base film. That is, the method of producing the depolarizing film can be performed by a roll-to-roll method, and in an exemplary embodiment, gravure coating in a roll-to- , Dip coating, or die coating method.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Example

A triacetylcellulose (TAC) film having no polarization degree dissolution was used as the base film. A 20% liquid crystal coating solution was applied on the top of the TAC film and the base film was moved at a rate of 10 m / min using Meyer bar 3 # Coating layer was formed, and after hot air drying at 80 캜 for 1 min, UV curing was performed. At this time, the liquid crystal was mixed with a general reactive mesogen liquid crystal (LC-1, ONS) and a room temperature liquid crystal (LC-2, ONS) in a ratio of 2: 1. In this case, a mixed solvent of Toluene and THF in a ratio of 4: 1 was used, and Meyer Bar used 3 # to form a 2 μm liquid crystal coating layer.

At this time, the haze was 0.55% and the degree of depolarization was measured as 25%.

Comparative Example

A polarizing elimination film was prepared in the same manner as in Example 1, except that a liquid crystal was coated to a thickness of 4 탆 and a polarizing elimination layer was formed so that the liquid crystal was aligned in a random direction.

Experimental Example  One

An image obtained by photographing the depolarizing film prepared in Production Example by a microscope on the side of the depolarizing layer is shown in FIG. 6. An image obtained by photographing the polarizing eliminating film prepared in Comparative Example by a microscope on the side of the depolarizing layer is shown in FIG. .

Referring to the image of the embodiment of FIG. 6, it can be seen that the liquid crystal of the depolarizing layer does not form a separate domain. Referring to the image of the comparative example of FIG. 7, can see.

Experimental Example  2

The haze value, the transmittance transmittance and the degree of depolarization of the depolarizing film prepared in Examples and Comparative Examples were measured and the numerical values thereof are shown in Table 1 below. The haze value and the transmittance of the depolarization film were measured using NDH-5000 (Nippon Denshoku), and the degree of depolarization was calculated by the equation (1).

Haze Light transmittance (%) Polarization degree (%) Example 0.55 91 25 Comparative Example 15 90 38

Referring to Table 1, it can be seen that the polarizing elimination film produced according to the Example exhibits a good reduction in haze, while exhibiting excellent light transmittance and polarized light elimination, while the polarizing elimination film produced according to the Comparative Example has haze The value is very high. Therefore, as in the present invention, there is a critical effect that when the liquid crystal is oriented in the angular range of -45 degrees to +45 degrees in the machine direction without the domain, the depolarization canceling film can lower the haze value very effectively .

It will be appreciated that the embodiments described above are all exemplary and that different embodiments may be applied in combination.

MD: Machine direction
TD: Direction perpendicular to machine direction
10: substrate film
20: Polarization canceling layer
21: liquid crystal
30: depolarization film
110: lower polarizer 120: upper polarizer
200: liquid crystal cell
210: first substrate 220: liquid crystal layer
230: second substrate
300: Backlight unit

Claims (13)

A base film; And
And a polarizing resolution layer comprising a liquid crystal coated on the base film,
Wherein an angle at which the liquid crystal is oriented is -45 DEG to + 45 DEG with respect to a machine direction of the base film. The method according to claim 1,
Wherein the thickness of the polarization canceling layer is in the range of 1 탆 to 3 탆. The method according to claim 1,
And the haze of said depolarization canceling film is within 2%. The method according to claim 1,
Wherein the base film comprises a polarizing film. The method according to claim 1,
Wherein the liquid crystal has a concentration range of 5% to 30%. The method according to claim 1,
Wherein the degree of depolarization of the polarizing elimination film is 20% or more. A liquid crystal cell;
Backlight unit;
A lower polarizer disposed between the liquid crystal cell and the backlight unit; And
A liquid crystal display device comprising the depolarizing film according to any one of claims 1 to 6. 8. The method of claim 7,
And the polarizing elimination film is disposed on the viewer side of the liquid crystal cell. 9. The method of claim 8,
And the base film is disposed between the depolarization layer and the liquid crystal cell. Moving the base film;
Coating a liquid crystal on the base film; And
And moving the base film through the roll between the rolls,
Wherein an angle at which the liquid crystal is oriented is -45 deg. To +45 deg. Relative to the machine direction of the base film. 11. The method of claim 10,
Wherein the moving speed of the base film is in the range of 3 m / s to 20 m / s. 11. The method of claim 10,
And UV-curing the coated liquid crystal. 11. The method of claim 10,
The step of coating the depolarization layer
A depolarizing film which is carried out by a gravure coating process, a dip coating process or a die coating process.

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