KR20190055880A - LCD structure - Google Patents

Abstract

The present invention relates to an LCD structure. Provided is the LCD structure comprising a light guide plate, a brightness enhancement film, optical sheets, and a liquid crystal panel. The brightness enhancement film comprises a base film, a YAG-base phosphor layer coated on an upper part of the base film, and a low refraction layer coated on an upper part of the YAG-base phosphor layer or a lower part of the base film. Thus, the present invention provides the LCD structure having improved brightness and viewing angle.

Description

LCD structure {LCD structure}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LCD structure, and more particularly, to an LCD structure capable of realizing excellent luminance and viewing angle.

Recently, the display market is evolving from a large-size and high-resolution competition to a color competition, and therefore, interest in displays capable of achieving excellent color is increasing.

OLED (Organic Light-Emitting Diode), which is widely regarded as the next generation display, can achieve the color reproduction rate up to 100% of NTSC. However, the present LCD shows 70% color reproduction rate to be.

Accordingly, although a method using a quantum dot is applied to improve the color gamut of an LCD, there is a problem that a sealing process through a barrier film must be accompanied by inherent characteristics of quantum dots susceptible to moisture and oxygen.

On the other hand, in the LCD, a luminance enhancement film is applied in order to increase the contrast. The brightness enhancement film can be attached to a back light unit (BLU) using a light shielding tape. The reflection type polarizing film is a film in which a high refractive index layer and a low refractive index layer are alternately repeatedly laminated, and commercially available is a dual brightness enhancement film (DBEF) ) Are used.

1, the conventional LCD structure includes a white LED 11 as a light source, a diffusion plate 12, a prism sheet 13, and a DBEF (not shown) sequentially arranged in front of the white LED 11 14, and a liquid crystal panel 15. Therefore, the light emitted from the white LED 11 is diffused by the diffusion plate 12, is condensed through the prism sheet 13, and brightness is improved while passing through the DBEF 14. [

However, recently, as the resolution of the display is increased, the number of pixels is increased, and the luminance is decreased. In particular, since the structure of the backlight is structurally impossible to further apply the LED for improving the luminance of the structure of the display, the necessity of the LCD structure capable of improving the brightness even under the low power is more urgently required to be.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an LCD structure capable of improving luminance and viewing angle.

As means for solving the above-mentioned technical problem,

The present invention provides an LCD structure including a light guide plate, a brightness enhancement film, optical sheets and a liquid crystal panel, wherein the brightness enhancement film comprises a base film, a YAG base phosphor layer coated on the base film, And a low refraction layer coated on the upper side of the substrate or the lower side of the substrate film.

In this case, the low refraction layer includes a urethane acrylate oligomer, and the urethane acrylate oligomer may have a fluorinated polyol as a main chain.

In this case, the urethane acrylate oligomer may be contained in an amount of 10 to 20 wt% with respect to the low refractive layer.

In this case, the low refraction layer may include hollow nanosilica.

In this case, the hollow nanosilica may be contained in an amount of 30 to 70 wt% with respect to the low refractive index layer.

In this case, the coating thickness of the low refraction layer may be 70 to 120 nm.

In this case, the refractive index of the low refractive index layer may be 1.32 to 1.42.

According to the present invention, since the brightness enhancement film and the optical sheets are sequentially disposed in front of the light source, the light emitted from the light source is improved in brightness by the brightness enhancement film, and the light is condensed and diffused by the optical sheets in an improved brightness state Therefore, the viewing angle can be improved.

Further, the brightness can be further improved by additionally coating a low refractive index layer on one side or both sides of the brightness enhancement film.

1 is a schematic diagram of an LCD structure according to the prior art,
Figure 2 is a schematic view of an LCD structure according to the present invention,
Figs. 3 to 5 are schematic views showing an embodiment of the LCD structure shown in Fig. 2,
Fig. 6 is a laminated structure of the brightness enhancement film of the LCD structure shown in Fig. 2,
7 and 8 are a laminated structure showing a modified example of the brightness enhancement film shown in Fig. 6,
9 is a schematic view showing a lamination process of a composite optical sheet according to the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

FIG. 2 is a schematic view of an LCD structure according to the present invention, FIGS. 3 to 5 are schematic views showing an embodiment of the LCD structure shown in FIG. 2, and FIG. 6 is a laminated structure of a luminance enhancement film of the LCD structure shown in FIG. And FIGS. 7 and 8 are laminated structure views showing a modified example of the brightness enhancement film shown in FIG.

2 to 8, an LCD structure according to the present invention includes a light source 110, a brightness enhancement film 120, optical sheets 130, and a liquid crystal panel 140.

The light source 110 is used to emit light used to implement visual information through the liquid crystal panel 140, and is installed at the end of the LCD structure. In the present invention, a blue LED may be used as the light source 110 .

In this case, the light guide plate 150 may be disposed between the light source 110 and the brightness enhancement film 120 to guide the light emitted from the light source 110 to the brightness enhancement film 120.

Here, only the shape in which the light source 110 is disposed directly underneath is exemplified, but it is of course possible to configure the light source 110 as an edge type.

The brightness enhancement film 120 is disposed between the light guide plate 150 and the optical sheets 130 to improve the brightness of the LCD.

Specifically, the brightness enhancement film 120 includes a base film 121, a YAG (Yttrium aluminum garnet) -based phosphor layer 122, and a low refractive layer 125.

The base film 121 may be a film of a material such as PET, TAC, PC, Polyimide, Acryl and the like, and is not particularly limited.

The YAG-base phosphor layer 122 is formed on one surface of the base film 121 to improve brightness. In this case, the YAG-base phosphor 124 constituting the YAG-base phosphor layer 122 may be Y ₃ Al ₅ 0 ₁₂ : Ce ³⁺ (YAG: Ce), Tb ₃ Al ₅ 0 ₁₂ : Ce ³⁺ (TAG: Ce) , Y ₃ Mg ₂ AlSi ₂ O ₁₂ : Ce ³⁺ , and Ca ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce ³⁺ .

The YAG-base phosphor layer 122 is formed by dispersing the YAG-base phosphor 124 in a polymer matrix 123 so as to secure physical properties such as pencil hardness, adhesion, curl, And the like.

In this case, the polymer matrix 123 may be selected from monofunctional urethane acrylate oligomers, monofunctional monomers, photoinitiators, leveling agents, antifoaming agents, and dispersants.

The YAG-base phosphor 124 is added in a proportion of 10 to 40 wt% with respect to 100 wt% of the coating liquid composed of the YAG-base phosphor 124 and the polymer matrix 123. If the content of the YAG-base phosphor 124 is less than 10 wt%, the desired brightness enhancement effect can not be exhibited. If the content is more than 40 wt%, the coating is difficult and the color reproduction rate is lowered.

The thickness of the YAG-base phosphor layer 122 is preferably 10 to 100 占 퐉. If the coating thickness is less than 10 탆, the YAG fluorescent material 124 may protrude to cause defects in appearance. If the coating thickness is more than 100 탆, curl characteristics may deteriorate during coating, and thus the resin applicable to the polymer matrix 123 may be limited .

As shown in FIGS. 6 to 8, a low refractive layer 125 is provided for further improving the brightness. The low refractive layer 125 is formed on the upper part of the YAG-base phosphor layer 122, the lower part of the base film 121, It may be coated on both the upper portion of the phosphor layer 122 and the lower portion of the base film 121.

The coating solution for formation of the low refraction layer 125 may include urethane acrylate oligomer, polyfunctional monomer, monofunctional monomer, photoinitiator, leveling agent, dispersant and hollow nanosilica.

In this case, the urethane acrylate oligomer has the following structure.

In this case, x, y, z, and n in R " are integers between 0 and 50.

That is, the urethane acrylate oligomer has a fluorinated polyol as a main chain and is contained in an amount of 10 to 20% with respect to the low refractive layer 125. When the content of the fluorinated polyol is less than 10 wt%, the refractive index of the low refractive layer 125 is increased to cause optical loss. When the content of the fluorinated polyol is more than 20 wt%, the monomer content decreases and the crosslink density decreases. it's difficult. Also, the polyfunctional monomer and the monofunctional monomer may be composed of PETA (pentaerythritol triacrylate) and ACMO (acryloyl morpholine), and they are contained in a proportion of 20 to 30 wt%. The photoinitiator, leveling agent and dispersant may be contained in an amount of 1 to 5 wt%.

On the other hand, hollow nanosilica can be hollow nanosilica manufactured by Nippon Shokubai Co., Ltd. It is preferable that 30 to 70 wt% of the hollow nano silica is included in the low refractive layer 125. If the content of the hollow nanosilica is less than 30 wt%, the reflectance increases by 2.5% or more to cause transmission light loss. If the content of the hollow nanosilica is more than 70%, the dispersion of the hollow nanosilica particles occurs and the appearance becomes uneven.

The low refraction layer 125 may be coated by a bar coating method, a slot-die coating method, or a micro gravure coating method.

The thickness of the low refractive layer 125 is preferably 70 to 120 nm. When the thickness of the low refraction layer 125 is less than 70 nm or exceeds 120 nm, the reflectance increases and a luminance lowering phenomenon due to transmission light loss may occur.

The refractive index of the low refractive layer 125 is preferably 1.32 to 1.42, and more preferably 1.34 to 1.38 in terms of luminance improvement.

Meanwhile, the brightness enhancement film 120 may further include a back coating layer (not shown). The back coating layer is formed by the particles included in the back coating layer to provide unevenness on the back surface of the brightness enhancement film 120 to prevent blocking with other optical sheets to improve workability and to prevent static electricity generated due to friction in the process Function.

In the present invention, the back coating may be a bar coating method or a slot-die coating method. The coating solution used for the back coating layer may include a urethane acrylate oligomer, a monofunctional monomer, a photoinitiator, a leveling agent, .

In this case, the PMMA particles are preferably contained in an amount of 0.1 to 5 wt% with respect to the entire back coating layer. When the content of PMMA particles is less than 0.1 wt%, sufficient irregularities can not be formed on the back surface of the brightness enhancement film. If the content of PMMA particles is more than 5 wt%, transmitted light loss due to high haze occurs. Therefore, the haze of the back coating layer is adjusted to 1 To 20%.

An antistatic agent may be added to the back coat layer as an additive if necessary. The surface resistance can be controlled by adding an antistatic agent. The antistatic agent is preferably contained in an amount of 0.01 to 3 wt% with respect to the whole of the back coat layer. When the content of the antistatic agent is less than 0.01wt%, and a lack of surface resistance for antistatic, 3wt% excess if it results in the addition of excess amount more than necessary to the antistatic agent 0.01 ~ 3wt% surface resistance of 10 ¹⁰ to 10 by the addition ¹² Ohm / < / RTI >< / RTI > This is because, when the surface resistance is 10 ¹⁰ to 10 ¹² Ohm / square, it is possible to prevent the film from being damaged in the dynamic state, and there is an effect that the charging phenomenon immediately after charging immediately attenuates.

The thickness of the back coating layer is preferably 1 to 10 mu m. When the thickness of the back coating layer is less than 1 mu m, sufficient irregularities are not formed on the back surface of the brightness enhancement film 120 to prevent blocking. When the back coating layer thickness is more than 10 mu m, there is a problem of transmission light loss due to high haze.

A method of manufacturing the brightness enhancement film 120 as described above is as follows.

First, a YAG fluorescent material 124 is uniformly dispersed in a polymer matrix 123 selected from a monofunctional urethane acrylate oligomer, a monofunctional monomer, a photoinitiator, a leveling agent, a defoaming agent, and an initiator at a concentration of 10 to 40 wt% The prepared coating solution is coated on the base film 121 to have a thickness of 5 to 100 μm and irradiated with ultraviolet rays to cure the YAG-based phosphor layer 122.

Thereafter, a coating solution containing a urethane acrylate oligomer, a polyfunctional monomer, a monofunctional monomer, a photoinitiator, a leveling agent, a dispersant, and hollow nanosilica is applied to the top of the YAG-base phosphor layer 122 or the bottom of the base film 121 When the low refraction layer 125 is formed by coating the upper part of the YAG-base phosphor layer 122 and the lower part of the substrate film 121 and irradiating ultraviolet rays to cure them, the brightness enhancement film 120 is completed.

In this case, as a coating method of the YAG-base phosphor layer 122 and the low refraction layer 125, Bar Coating, Spin Coating and Slot-die Coating may be used, but it is preferable to coat them by a Slot-die Coating method. In addition, a metal halide lamp, a mercury high-pressure lamp, and a non-electrode lamp can be used for ultraviolet ray irradiation after coating, but it is preferable to irradiate with a non-electrode lamp in a nitrogen atmosphere. The curing time is preferably 1 to 10 seconds.

The optical sheets 130 are disposed between the brightness enhancement film 120 and the liquid crystal panel 140 to improve the viewing angle of the LCD.

In the present invention, the optical sheets 130 may be the prism sheet 131 and the lens film 132 shown in Fig. 3, the MOP (Micro Lens On Prism) 133 shown in Fig. 4, The prism sheet 134 and the diffusion sheet 135 may be used. More specifically, when the optical sheets 130 are composed of the prism sheet 131 and the lens film 132 sequentially arranged in the front direction, light having improved brightness while passing through the brightness enhancement film 120 is reflected by the prism sheet 131 And is diffused again by the lens film 132 to improve the viewing angle. In this case, it is preferable to use a double-sided prism sheet POP as the prism sheet 131.

In addition, when the optical sheets 130 are formed of the MOP 133, light can be condensed and diffused by the MOP 133 to improve the viewing angle. In addition, light condensation and diffusion are performed by one MOP 133 Therefore, it is possible to slim down the LCD.

In addition, when the optical sheets 130 are composed of the prism sheet 134 and the diffusion sheet 135 sequentially arranged forward, light is condensed by the prism sheet 134 and diffused again by the diffusion sheet 135 The viewing angle can be improved.

Meanwhile, the present invention can adhere a plurality of films constituting an LCD in the form of a composite optical sheet. That is, the brightness enhancement film 120 and the optical sheets 130 may be laminated with an adhesive to form a composite optical sheet, which is then applied to an LCD.

In this case, various known adhesives can be used as the adhesive, and it is preferable to use a transparent adhesive (OCA, Optical Clear Adhesive), though it is not particularly limited, and it can be bonded by direct bonding (full lamination) or air gap bonding . In particular, the direct bonding method has a lower yield compared to the air gap bonding method, but has the advantage of high visibility due to excellent optical characteristics and low power consumption.

Lamination in the present invention can be performed by a process as shown in FIG.

First, the optical sheet F1 is supplied by the first supply roller R1, and the brightness enhancement film F2 is supplied by the second supply roller R2. Thereafter, the optical sheet F1 is passed through the adhesive application roller R3, and the adhesive A is applied to at least one surface of the optical sheet F1, and then passes through the lamination roller R4, It is welded. When the optical sheet F1 is composed of only MOP, the composite optical sheet F3 is completed by a single laminating process. Alternatively, the optical sheet F1 may be formed of two or more kinds of prism sheet and lens film, And the diffusion sheet, the first optical sheet is laminated on the brightness enhancement film F2, and the second optical sheet is laminated on the laminate of the brightness enhancement film F2 and the first optical sheet in the above- The sheet F3 is completed. 9, reference character "r" denotes a guide roller for guiding the brightness enhancement film F2 supplied from the second supply roller R2 to the lint roller R4.

The liquid crystal panel 140 is disposed at the forefront of the LCD structure for converting light into visual information and emitting the light to the outside.

The LCD structure according to the present invention has been described above. Hereinafter, embodiments of the present invention will be described. The present invention can be understood more clearly by the following examples, which are merely illustrative of the present invention and are not intended to limit the scope of the present invention.

Example 1

400 g (40 wt%) of urethane (meth) acrylate (Ebecryl 1290, Korea) was added to a reactor equipped with a stirrer, and 400 g (40 wt%) of isobonyl acrylate as a reactive monomer diluent and 2-hydroxyethyl acrylate 10 g (1 wt%) of BYK307, a leveling agent, 10 g (1 wt%) of BYK307, 10 g (1 wt%) of FA-4420, a fluorescent dispersant BASF, and 10 g 20 g (2 wt%) of Irgacure 184, a photoinitiator manufactured by BASF, was added, 100 g (10 wt%) of YAG phosphor was added and stirred at 400 rpm for 30 minutes at room temperature to obtain a transparent liquid composition having a viscosity of 1,000 cps. Thereafter, the prepared coating solution was coated on one side of the PET film with a Bar Coater to a thickness of 50 μm, and irradiated with ultraviolet rays for about 5 seconds using a non-electrode lamp. In this case, the amount of irradiated ultraviolet light was set to 1000 mj or less.

Subsequently, on the upper side of the prepared phosphor-coated PET film, a low refractive coating liquid TU2359 manufactured by JSR Corporation was coated on both sides and one side with a thickness of 100 nm using a slot die coater and then irradiated with ultraviolet rays for about 5 seconds using a non-electrode lamp . In this case, the amount of irradiated ultraviolet light was set to 1000 mJ or less.

Finally, a liquid crystal display was manufactured by disposing a reflective plate, a light source (Blue LED), an optical sheet and a liquid crystal display panel sequentially, and arranging the brightness enhancement film prepared above between the light source and the optical sheet.

Example 2

400 g (40 wt%) of urethane (meth) acrylate (Ebecryl 1290, Korea) was added to a reactor equipped with a stirrer, and 400 g (40 wt%) of isobonyl acrylate as a reactive monomer diluent and 2-hydroxyethyl acrylate 10 g (1 wt%) of BYK307, a leveling agent, 10 g (1 wt%) of BYK307, 10 g (1 wt%) of FA-4420 of a fluorescent dispersant BASF, and 10 g 20 g (2 wt%) of Irgacure 184, a photoinitiator manufactured by BASF, was added, 200 g (20 wt%) of YAG fluorescent material was added and stirred at 400 rpm for 30 minutes at room temperature to obtain a transparent liquid composition having a viscosity of 1,000 cps. Thereafter, the prepared coating solution was coated on one side of the PET film with a Bar Coater to a thickness of 50 μm, and irradiated with ultraviolet rays for about 5 seconds using a non-electrode lamp. In this case, the amount of irradiated ultraviolet light was set to 1000 mj or less.

Subsequently, on the upper side of the prepared phosphor-coated PET film, a low refractive coating liquid TU2359 manufactured by JSR Corporation was coated on both sides and one side with a thickness of 100 nm using a slot die coater and then irradiated with ultraviolet rays for about 5 seconds using a non-electrode lamp . In this case, the amount of irradiated ultraviolet light was set to 1000 mJ or less.

Finally, a liquid crystal display was manufactured by disposing a reflective plate, a light source (Blue LED), an optical sheet and a liquid crystal display panel sequentially, and arranging the brightness enhancement film prepared above between the light source and the optical sheet.

Example 3

400 g (40 wt%) of urethane (meth) acrylate (Ebecryl 1290, Korea) was added to a reactor equipped with a stirrer, and 400 g (40 wt%) of isobonyl acrylate as a reactive monomer diluent and 2-hydroxyethyl acrylate 10 g (1 wt%) of BYK307, a leveling agent, 10 g (1 wt%) of BYK307, 10 g (1 wt%) of FA-4420, a fluorescent dispersant BASF, and 10 g 20 g (2 wt%) of Irgacure 184, a photoinitiator manufactured by BASF, was added, 300 g (30 wt%) of YAG phosphor was added and stirred at 400 rpm for 30 minutes at room temperature to obtain a transparent liquid composition having a viscosity of 1,000 cps. Thereafter, the prepared coating solution was coated on one side of the PET film with a Bar Coater to a thickness of 50 μm, and irradiated with ultraviolet rays for about 5 seconds using a non-electrode lamp. In this case, the amount of irradiated ultraviolet light was set to 1000 mj or less.

Subsequently, on the upper side of the prepared phosphor-coated PET film, a low refractive coating liquid TU2359 manufactured by JSR Corporation was coated on both sides and one side with a thickness of 100 nm using a slot die coater and then irradiated with ultraviolet rays for about 5 seconds using a non-electrode lamp . In this case, the amount of irradiated ultraviolet light was set to 1000 mJ or less.

Finally, a liquid crystal display was manufactured by disposing a reflective plate, a light source (Blue LED), an optical sheet and a liquid crystal display panel sequentially, and arranging the brightness enhancement film prepared above between the light source and the optical sheet.

Comparative Example 1

A liquid crystal display device was manufactured in the same manner as in Example 1, except that the low refractive index layer was not coated on the luminance enhancement film.

Comparative Example 2

A liquid crystal display device was produced in the same manner as in Example 3, except that the low refractive index layer was not coated on the luminance enhancement film.

Experimental Example

The front luminance and the color reproduction ratio of the luminance enhancement film were measured through a luminance measuring apparatus (BM-7 FAST color difference luminance meter, Topcon, Japan) in the liquid crystal display apparatus manufactured according to the examples and comparative examples. 1]. For reference, the experimental data in the case where the low refractive index layer is not formed on the brightness enhancement film in the present invention is specifically disclosed in Patent Application No. 10-2017-0150091 filed by the present applicant.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Low refraction layer coating section both sides section both sides section both sides - - Color recall (%) 81.3 81.3 82.6 82.6 82.2 82.2 81.3 82.6 Brightness (nit) 441 452 492 504 523 536 430 480

110: light source 120: brightness enhancement film
121: base film 122: YAG-base phosphor layer
123: polymer matrix 124: YAG-base phosphor
125: low refraction layer 130: optical sheets
131: prism sheet 132: lens film
133: MOP 134: prism sheet
135: diffusion sheet 140: liquid crystal panel
150: light guide plate
F1: Optical sheet F2: Brightness improving film
F3: Composite optical sheet R1: First supply roller
R2: second supply roller R3: adhesive application roller
R4: Lapping roller r: Guide roller

Claims (7)

An LCD structure including a light guide plate, a brightness enhancement film, optical sheets and a liquid crystal panel,
Wherein the brightness enhancement film comprises a base film, a YAG-base phosphor layer coated on the base film, and a low refractive layer coated on an upper portion of the YAG-base phosphor layer or a lower portion of the base film. . The method according to claim 1,
Wherein the low refraction layer comprises a urethane acrylate oligomer, and the urethane acrylate oligomer has a fluorinated polyol as a main chain. 3. The method of claim 2,
Wherein the urethane acrylate oligomer is contained in an amount of 10 to 20 wt% based on the low refractive index layer. The method according to claim 1,
Wherein the low refraction layer comprises hollow nanosilica. 5. The method of claim 4,
Wherein the hollow nanosilica is contained in an amount of 30 to 70 wt% with respect to the low refractive index layer. 6. The method according to any one of claims 1 to 5,
Wherein the coating thickness of the low refraction layer is 70 to 120 nm. 6. The method according to any one of claims 1 to 5,
And the refractive index of the low refractive layer is 1.32 to 1.42.

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