KR20180056581A - LCD structure - Google Patents

Abstract

The present invention relates to an LCD structure which comprises: a light source; and a prism sheet, a dual brightness enhancement film (DBEF), and a liquid crystal panel which are sequentially arranged in front of the light source. The brightness enhancement film is arranged between the light source and the prism sheet, and includes a substrate film and a LuAg-based phosphor layer coated on one surface of the substrate film, thereby improving the brightness and a viewing angle of the LCD structure.

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 prism sheet, a DBEF, and a liquid crystal panel, wherein at least one of the brightness enhancing film and the DBEF, between the light guide plate and the prism sheet, between the light guide plate and the DBEF, Wherein the brightness enhancement film comprises a base film and a LuAG-based phosphor layer coated on one surface of the base film.

In this case, the LCD structure may further include a light source, and the light source may be a blue LED.

In this case, the LuAG-based phosphor layer may be one in which the LuAG-based phosphor is dispersed in the polymer matrix.

In this case, the LuAG-based phosphor of the LuAG-based phosphor layer is preferably selected from Lu ₃ Al ₅ O ₁₂ : Ce ³⁺ , Tb ₃ Al ₅ O ₁₂ : Ce ³⁺ , Lu ₂ CaMg ₂ Si ₃ O ₁₂ : Ce ³⁺ And the like.

In this case, the LuAG-based phosphor layer may be formed by adding 10 to 40 wt% of the LuAG-based phosphor to 100 wt% of the coating solution comprising the LuAG-based phosphor and the polymer matrix.

In this case, the coating thickness of the LuAG-based phosphor layer may be 10 to 100 mu m.

In this case, the light guide plate, the brightness enhancement film, the prism sheet, and the DBEF may be sequentially arranged in the LCD structure.

In this case, the brightness enhancement film may include a back coating layer including PMMA and an antistatic agent on one side.

In this case, the back coating layer may contain 0.1 to 5 wt% of the PMMA.

In this case, the back coat layer may contain 0.01 to 3 wt% of the antistatic agent.

The present invention also provides a brightness enhancement film comprising a base film and a LuAG-based phosphor layer coated on one surface of the base film, a prism sheet and a DBEF, wherein the brightness enhancement film, the priming sheet, and the DBEF The composite optical sheet being characterized in that it is laminated in one piece.

In this case, the brightness enhancement film may include a back coating layer including PMMA and an antistatic agent on one side.

According to the present invention, in order to improve brightness, a brightness enhancement film is disposed between a light source and a prism sheet in an LCD structure to which a DBEF is applied, so that light emitted from a light source is provided as a prism sheet It is possible to improve the luminance and the viewing angle.

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,
FIG. 3 is a stacked structure of the brightness enhancement film of the LCD structure shown in FIG. 2,
4 is a schematic view showing a lamination process of a composite optical sheet according to the present invention,
5 is a graph showing the results of measurement of the viewing angle of an LCD manufactured according to Production Example, Comparative Production Examples 1 and 2;

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, and FIG. 3 is a stacked structure view of a brightness enhancement film of the LCD structure shown in FIG.

2 and 3, an LCD structure according to the present invention includes a light source 110, a prism sheet 120, a DBEF 130, a liquid crystal panel 140, and a brightness enhancement film 150 .

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 160 may be disposed between the light source 110 and the brightness enhancement film 150 to guide the light emitted from the light source 110 to the brightness enhancement film 150.

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 prism sheet 120 is disposed in front of the light guide plate 160 to condense light guided by the light guide plate 160.

The DBEF 130 is disposed in front of the prism sheet 120 for improving the luminance of the LCD.

In this case, the prism sheet 120 and the DBEF 130 may be disposed in the opposite manner. That is, the DBEF 130 may be disposed in front of the light guide plate 160, and the prism sheet 120 may be disposed in front of the DBEF 130.

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 light source 110, the prism sheet 120, the DBEF 130, the liquid crystal panel 140, and the light guide plate 160 described above can be applied to any of commonly known ones without any particular limitation .

The luminance enhancement film 150 is provided between the light guide plate 160 and the prism sheet 120, between the light guide plate 160 and the DBEF 130, between the prism sheet 120 and the DBEF 130, Or at least one of them.

Specifically, the brightness enhancement film 150 includes a base film 151 and a LuAG-base phosphor layer 152 as shown in Fig.

The base film 151 may be a film of a material such as PET, TAC, PC, Polyimide, Acryl, and the like, and is not particularly limited.

The LuAG-based phosphor layer 152 is coated on one surface of the base film 151 for improving brightness. In this case, the LuAG-based fluorescent material 154 constituting the LuAG-based fluorescent material layer 152 is composed of Lu ₃ Al ₅ O ₁₂ : Ce ³⁺ , Tb ₃ Al ₅ O ₁₂ : Ce ³⁺ , Lu ₂ CaMg ₂ Si ₃ O ₁₂ : Ce ³⁺ . &^{Lt; /} RTI >

The LuAG-based phosphor layer 152 is formed by dispersing a LuAG-based phosphor 154 in a polymer matrix 153 so as to secure physical properties such as pencil hardness, adhesion, curl, And the like.

In this case, the polymer matrix 153 may be selected from monofunctional urethane acrylate oligomers, monofunctional monomers, photoinitiators, leveling agents, antifoaming agents, and dispersants.

The LuAG-base phosphor 154 is added in a proportion of 10 to 40 wt% with respect to 100 wt% of the coating liquid composed of the LuAG-base phosphor 154 and the polymer matrix 153. If the content of the LuAG-based phosphor 154 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 LuAG-based phosphor layer 152 is preferably 10 to 100 mu m. If the coating thickness is less than 10 μm, the LuAG-based fluorescent material 154 protrudes to cause appearance defects. If the coating thickness is more than 100 μm, the Curl characteristic of the coating deteriorates and the resin applicable to the polymer matrix 153 is limited .

Meanwhile, the brightness enhancement film 150 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 irregularities on the back surface of the brightness enhancement film 150 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 150 to prevent blocking, and when the back coating layer thickness is more than 10 mu m, there is a problem of transmission light loss due to high haze.

The brightness enhancement film 150 as described above can be obtained by uniformly dispersing the LuAG-based phosphor 154 in the polymer matrix 153 to prepare a coating solution, coating the coating solution on one side or both sides of the base film 151, Irradiation and curing.

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 150, the prism sheet 120, and the DBEF 130 may be laminated with an adhesive to form a single composite optical sheet and 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 prism 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 prism sheet F1 passes through the adhesive application roller R3, and the adhesive A is applied to at least one side of the prism sheet F1, and then passes through the laminating roller R4 while passing through the brightness enhancement film F2 It is welded. Finally, the composite optical sheet F3 is completed by laminating the DBEF to the laminated prism sheet F1 and the brightness enhancement film F2 in the same manner as described above. 4, reference numeral "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 LCD structure according to the present invention has been described above. Hereinafter, embodiments of the present invention will be described.

Manufacturing example

Manufacture of brightness enhancement film

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 LuAG 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.

Manufacture of LCD

A brightness enhancement film, a prism sheet, a DBEF, and a liquid crystal panel were sequentially disposed in front of the blue LED to manufacture an LCD according to the present invention.

Comparative Preparation Example 1

The LCD was manufactured in the same manner as the production example except that DBEF was removed.

Comparative Production Example 2

The LCD was manufactured in the same manner as the production example except that the DBEF and the prism sheet were removed.

Example 1

The brightness was measured while moving the position of the brightness enhancement film forward in the LCD manufactured according to the manufacturing example, and the results are shown in Table 1 below.

Brightness Enhancement Film Location Between the light guide plate and the prism sheet Between prism sheet and DBEF Between DBEF and LCD panel Liquid crystal panel front Brightness (nit) 764.7 609.8 162.1 38.7

Example 2

The luminance and viewing angle of the LCD manufactured according to Production Examples 1 and 2 were measured. The results are shown in [Table 2] and FIG. 4, respectively.

division Manufacturing example Comparative Preparation Example 1 Comparative Production Example 2 Brightness (nit) 764.7 539.3 155.2

[Table 2] shows that the brightness enhancement effect of the present invention is enhanced when the brightness enhancement film of the present invention is applied to the quantum dot TV (100%), and particularly when the DBEF and the brightness enhancement film are applied together. It can also be seen from FIG. 4 that by applying the DBEF and the luminance enhancement film together, it is possible to secure excellent luminance characteristics over the entire viewing angle range.

Example 3

The luminance was measured while adjusting the LuAG-based phosphor content of the luminance enhancement film to 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt% and 50 wt% in the LCD manufactured according to the manufacturing example. ].

division Ref. DBEF
(LED TV) Ref. DBEF
(QD TV) Luag
5 wt% Luag
10wt% Luag
20wt% Luag
30wt% Luag
40wt% Luag
50wt% Luminance [nit] 430 450 410 610 660 690 720 680 Color Reproduction [%] 81.6 100 79.6 81.1 82.4 82.1 81.1 74.8

It can be seen from the [Table 3] that as the content of the LuAG-based phosphor increases, the luminance increases, and in particular, excellent characteristics are exhibited in the range of 10 to 40 wt%.

Example 4

The Curl characteristics of the brightness enhancement film according to the thickness of the LuAG-based phosphor coating were measured on an LCD manufactured according to the manufacturing example, and the results are shown in Table 4 below.

section Coating Thickness [탆] 5 10 30 50 70 100 120 150 Curl [mm] 0 3 4 7 10 18 22 25

[Table 4] shows that in the case of the single-sided coating, when the coating thickness of the LuAG-based phosphor is 10 to 100 μm, the Curl generation amount is 20 mm or less.

110: light source 120: prism sheet
130: DBEF 140: liquid crystal panel
150: Brightness improving film 151: Base film
152: LuAG-based phosphor layer 153: polymer matrix
154: LuAG-based phosphor 160: light guide plate
F1: prism sheet F2: brightness enhancement film
F3: Composite optical sheet R1: First supply roller
R2: second supply roller R3: adhesive application roller
R4: Lapping roller r: Guide roller

Claims (12)

In an LCD structure including a light guide plate, a prism sheet, a DBEF, and a liquid crystal panel,
A brightness enhancement film is disposed on at least one of the light guide plate and the prism sheet, between the light guide plate and the DBEF, and between the prism sheet and the DBEF, wherein the brightness enhancement film is coated on one side of the base film and the base film And a LuAG-based phosphor layer. The method according to claim 1,
Wherein the LCD structure further comprises a light source, wherein the light source is a blue LED. The method according to claim 1,
Wherein the LuAG-based phosphor layer comprises a LuAG-based phosphor dispersed in a polymer matrix. The method according to claim 1,
Wherein the LuAG-based phosphor of the LuAG-based phosphor layer is at least one selected from Lu ₃ Al ₅ O ₁₂ : Ce ³⁺ , Tb ₃ Al ₅ O ₁₂ : Ce ³⁺ , Lu ₂ CaMg ₂ Si ₃ O ₁₂ : Ce ³⁺ ≪ / RTI > The method according to claim 1,
Wherein the LuAG-base phosphor layer is formed by adding 10 to 40 wt% of the LuAG-base phosphor to 100 wt% of the coating solution comprising the LuAG-base phosphor and the polymer matrix. The method according to claim 1,
Wherein the coating thickness of the LuAG-based phosphor layer is 10 to 100 占 퐉. The method according to claim 1,
Wherein the LCD structure includes the light guide plate, the brightness enhancement film, the prism sheet, and the DBEF sequentially arranged. 8. The method according to any one of claims 1 to 7,
Wherein the brightness enhancement film includes a back coating layer including PMMA and an antistatic agent on one side thereof. 9. The method of claim 8,
Wherein the back coating layer comprises 0.1 to 5 wt% of the PMMA. 9. The method of claim 8,
Wherein the back coating layer contains 0.01 to 3 wt% of the antistatic agent. A brightness enhancement film comprising a base film and a LuAG-based phosphor layer coated on one surface of the base film, a prism sheet and a DBEF, wherein the brightness enhancement film, the priming sheet and the DBEF are laminated together . 12. The method of claim 11,
Wherein the brightness enhancement film comprises a back coating layer including PMMA and an antistatic agent on one surface thereof.

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