KR101961042B1 - Liquid Crystal Display device using high brightness film and composite sheet for liquid crystal display - Google Patents

Abstract

The present invention relates to a liquid crystal display device using a high luminance film, characterized by further comprising a DBEF on a high luminance film in which a coating layer containing a YAG fluorescent material and a LuAG fluorescent material is coated on a base film and a pattern portion is formed on the coating layer And a composite sheet for a liquid crystal display.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display device and a liquid crystal display (LCD)

The present invention relates to a liquid crystal display device using a high luminance film, and more specifically, a high brightness film (HBF) layer including YAG and LuAG fluorescent material is formed on a base film, To a liquid crystal display device using a high-luminance film for improving the luminance of an LCD and a composite sheet for a liquid crystal display device.

In the past, 40-inch TVs were the mainstream, but now more consumers are buying 50-inch TVs and even 60-inch TVs. Recently, competition for the manufacture of displays with excellent luminance and color has been emerging as the size competition ends.

OLED (Organic Light-Emitting Diode), which is the next generation display, is able to achieve 100% color reproduction rate (NTSC standard), but the existing LCD (Liquid Crystal Display) is 70% have.

Particularly, a liquid crystal display (LCD) displays images using the optical characteristics of liquid crystal. Since a liquid crystal panel for displaying an image is a non-light emitting type device that does not emit light by itself, And a backlight unit (BLU) for supplying light to the light source.

At this time, the BLU illuminates the backlight of the LCD which can not emit light evenly so that the display image can be seen. These BLUs use direct-lit BLUs, which are a method of evenly arranging LED BLUs behind the LCD panel, and LED BLUs at left and right corners, which are used to uniformly distribute the light generated from the LEDs (Edge-lit BLU), which is a method of reflecting light onto a substrate, and edge-type.

In the conventional liquid crystal display device, a brightness enhancement film is applied to increase the contrast, and the brightness enhancement film can be attached to the backlight unit by the light shielding tape. A reflection type polarizing film is used as a brightness enhancement film. 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. Commercially, DBEF (Dual Brightness Enhancement Film) of 3M Company is used.

Conventional LCD TVs using a DBEF film as a conventional brightness enhancement film have a structure as shown in Fig. A white LED layer, a diffusion plate, a prism sheet, a DBEF film, and a panel are stacked in this order from the bottom. That is, the light from the white LED is condensed through the prism sheet and the brightness is improved by passing through the DBEF film.

However, there is a need for development of a material having better brightness enhancement performance than DBEF film, which is a conventional brightness enhancement film.

In order to solve the problems of the related art as described above, the present invention provides a liquid crystal display device using a high luminance film which can be used in a structure to which a DBEF film is applied, and a composite sheet for a liquid crystal display device.

At this time, the LCD structure is characterized by including both a high luminance film and a DBEF film.

Further, the high-luminance film is characterized by forming a pattern portion.

The present invention relates to a liquid crystal display device and a liquid crystal display device using a high-luminance film, characterized in that a base film is coated with a coating layer containing a YAG-base phosphor and a LuAG-base phosphor, and the coating layer further includes DBEF in a high- And a composite sheet for a display device.

The liquid crystal display device using the high brightness film of the present invention is characterized in that the amount of the YAG-base phosphor and the LuAG-base phosphor is 10 to 40 wt% for the YAG-base phosphor and 1 to 20 wt% for the LuAG- .

The coating thickness of the coating layer is 10 to 100 탆.

In addition, YAG-base phosphor is _{Y 3 A1 5 0 12: Ce} 3 + (YAG: Ce), Tb 3 A1 5 0 12: Ce 3 + (TAG: Ce), Ca 3 (Sc, Mg) 2 Si 3 O 12 ^{_{: Ce 3+, Y 3 Mg 2}} AlSi 2 O 12: characterized in that the at least one of a Ce ^{+ 3.}

Also, LuAG base phosphor Lu ₃ Al ₅ O _12: characterized in that the at least one of a ^{Ce 3 +: Ce 3 +,} Tb 3 Al 5 O 12: Ce 3 +, Lu 2 CaMg 2 Si 3 O 12.

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Further, it is characterized by including a composite sheet having a high-luminance film and a DBEF adhered thereto.

Further, the high-luminance film is characterized by including a back coating layer containing PMMA particles or PMMA particles and an antistatic agent.

The PMMA particles may be contained in an amount of 0.1 to 5 wt% based on the white coating layer.

The antistatic agent is contained in an amount of 0.01 to 3 wt% relative to the back coat layer.

The back coating layer has a thickness of 1 to 10 mu m.

The composite sheet for a liquid crystal display of the present invention is characterized in that a base film is coated with a coating layer containing a YAG-base phosphor and a LuAG-base phosphor, and the coating layer is formed by sequentially laminating a high luminance film and a DBEF, .

The amount of the YAG-base phosphor and the LuAG-base phosphor is 10 to 40 wt% for the YAG-base phosphor and 1 to 20 wt% for the LuAG-base phosphor relative to the entire coating layer.

The coating thickness of the coating layer is 10 to 100 탆.

Further, the high-luminance film is characterized by including a back coating layer containing PMMA particles or PMMA particles and an antistatic agent.

When the combination of the optical sheet of the present invention, that is, the high luminance film on which the pattern portion is formed and the DBEF film are applied to the LCD, it is possible to realize excellent brightness and color reproduction ratio as compared with LCD using only existing DBEF film

1 is a schematic diagram of an LCD structure according to the prior art.
2 is a schematic diagram of an LCD structure according to the present invention.
FIG. 3 is a graph showing a comparison of luminance characteristics of the general LCD TV of FIG. 1 and the LCD of FIG. 2 using the high-luminance film according to the viewing angle.
Fig. 4 shows the results of comparing the luminance characteristics of the example, the comparative example 1, and the comparative example 2 with respect to the viewing angle.
5 is a schematic view comparing (a) a quantum dot film and (b) a high luminance film formed with a pattern portion of the present invention.
Figs. 6 to 11 are each an embodiment of the pattern portion. Fig.
12 is a schematic view of a process for laminating a high-luminance film of the present invention and another optical film.

The present invention will be described in detail below, and the following embodiments or examples are for illustrative purposes only and the present invention is not necessarily limited thereto.

According to the present invention, the luminance of the LCD can be improved by using the high luminance film 100 in which the pattern portion is formed together with the DBEF film 14. That is, the brightness of the liquid crystal display device is improved through the LCD structure including the high luminance film 100 including the YAG-base phosphor and the LuAG-base phosphor and the DBEF film 14 in the base film.

Specifically, according to a preferred embodiment of the present invention, a phosphor is a DBEF film (hereinafter referred to as a " DBEF film ") including both a YAG (Yittrium aluminum garnet )- based phosphor emitting yellow fluorescence and a LuAG (14) to improve the brightness of the LCD.

Examples of the base film used in the present invention include PET, TAC, PC, polyimide, and acryl film.

In the present invention, YAG (Yittrium aluminum garnet) -based phosphors and LuAG (Lutetium aluminum garnet) -based phosphors that emit yellow fluorescence may be used together to improve brightness and color reproducibility.

The YAG-base phosphor is _{Y 3 A1 5 0 12: Ce} 3 + (YAG: Ce), Tb 3 A1 5 0 12: Ce 3 + (TAG: Ce), Ca 3 (Sc, Mg) 2 Si 3 O 12: ^{_{Ce 3+, Y 3 Mg 2 AlSi}} 2 O 12: it is preferable that at least one of a Ce ^{+ 3.}

The LuAG base phosphor _{Lu 3 Al 5 O 12: Ce} 3 +, Tb 3 Al 5 O 12: Ce 3 +, Lu 2 CaMg 2 Si 3 O 12: it is preferable that at least one of a Ce ^{+ 3.}

YAG-base phosphor and LuAG-base phosphor are mixed at a ratio of 10 wt%: 1 wt% to 40 wt%: 20 wt%.

That is, the amounts of the YAG-base phosphor and the LuAG-base phosphor are 10 wt% to 40 wt% for the YAG-base phosphor and 1 wt% to 20 wt% for the LuAG-based phosphor.

If the lower limit value of the YAG-base phosphor is less than 10 wt%, the luminance improvement effect is insignificant. If the upper limit value is more than 40 wt%, the color reproduction rate, which is important in LCD TV, is lowered. Therefore, the YAG content is preferably in the range of 10 wt% to 40 wt%.

When the lower limit value of the LuAG phosphor is less than 1 wt%, the luminance improvement effect is insignificant. When the upper limit value is more than 20 wt%, the important color reproduction rate is lowered in the LCD TV, and thus the LuAG content is preferably in the range of 1 wt% to 20 wt% .

Improvement of luminance according to the content of YAG-base phosphor and LuAG-base phosphor division Ref. DBEF
(LED TV) YAG / LuAG content YAG 10 YAG 10 YAG 10 YAG 20 YAG 20 YAG 20 YAG 40 YAG 40 YAG 40 LuAG 5 LuAG 10 LuAG 20 LuAG 5 LuAG 10 LuAG 20 LuAG 5 LuAG 10 LuAG 20 Luminance [nit] 430 650 700 750 720 760 800 750 780 820 Color Reproduction [%] 81.6 81.8 82.4 82.6 82.3 82.4 82.6 79.2 79 78.5

A coating layer containing a phosphor is prepared by combining the YAC-base phosphor and the LuAG-base phosphor with a polymer matrix for securing physical properties.

Specifically, the YAG-base phosphor and the LuAG-base phosphor are uniformly dispersed in the polymer matrix by a stirrer to prepare a coating solution containing the phosphor first.

The polymer matrix may be a monofunctional urethane acrylate oligomer, a monofunctional monomer or the like, and a photoinitiator, a leveling agent, a defoaming agent, and the like may be added.

Examples of the photoinitiator include IG184, IG907, TPO, CP4, and the like. Preferred photoinitiators are IG 184 and TPO.

Particularly, the physical properties refer to properties such as pencil hardness, adhesion, curl, flexural resistance and the like.

- Pencil Hardness: To measure the hardness of the surface of the coating layer, the pencil of various hardness was scratched with a constant load to evaluate the hardness (Specification: JIS K 5400-8.4)

- Adhesion force: In order to measure the adhesion between the base film and the coating layer, the coating layer was scratched at a predetermined interval of 10 * 10 (lattice spacing 1 mm), and a tape was attached and peeled off to evaluate the adhesion between the coating layer and the base layer (Specification: JIS K 5400- 8.5)

-Curl: Curl (curling) property evaluation of film by measuring height of four corners of coating film by cutting coating film to 100mm * 100mm

* When Curl is severe, the film is curled and workability is lowered.

- Flexibility: rounding the film on a round bar to evaluate the flexibility of the coating film and coating film

The pattern portion may be formed on the coating layer containing the phosphor of the present invention.

One embodiment of the pattern portion is shown in Figures 6-11.

Specifically, the pattern portion may include any one of triangular, pyramidal, hemispherical, and non-spherical shapes.

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After applying the coating solution to one side of the base film, the engraved pattern is lapped, and after pre-curing using UV lamp, the engraved pattern is removed. The phosphor applied pattern thus removed is cured using a non-electrode lamp to prepare a coating layer having a patterned portion.

The brightness and color reproducibility characteristics of the present invention can be controlled by the thickness of the coating layer and the phosphor content.

When the coating of the coating layer on which the pattern unit is formed is performed, as the thickness of the coating layer is increased, the curling property is deteriorated and the resin applicable to the polymer matrix is limited. Therefore, the thickness of the coating layer should not be too thick.

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

When the coating layer is coated on the base film, the thickness of the coating layer is preferably 10 to 100 占 퐉.

If the coating thickness of the coating layer is less than 10 탆, the phosphor may protrude to cause defects in appearance. If the coating thickness exceeds 100 탆, curl characteristics may deteriorate during coating, which may restrict the resin applicable to the polymer matrix.

When DBEF and HBF are used together, luminance and color reproducibility according to desirable phosphor blending ratio division YAG 10 YAG 20 YAG 40 LuAG 5 LuAG 10 LuAG 20 LuAG 5 LuAG 10 LuAG 20 LuAG 5 LuAG 10 Luminance [nit] 650 700 750 720 760 800 750 780 Color Reproduction [%] 81.8 82.4 82.6 82.3 82.4 82.6 82 81.5

When DBEF and HBF are used together, luminance and color reproducibility according to mixing ratios other than the desirable phosphor mixture ratio (1) division Ref. DBEF Ref. DBEF YAG: LuAG YAG 50 (LED TV) (QD TV) content wt% LuAG 5 LuAG 10 LuAG 20 Luminance [nit] 430 450 Luminance [ nit ] 710 730 740 Color Reproduction [%] 81.6 100 Color Reproduction [ % ] 72.3 71.3 71.3

When DBEF and HBF are used together, luminance and color reproducibility according to mixing ratios other than the desirable phosphor mixture ratio (2) division Ref. DBEF Ref. DBEF YAG: LuAG YAG 5 (LED TV) (QD TV) content wt% LuAG 5 LuAG 10 LuAG 20 Luminance [nit] 430 450 Luminance [ nit ] 480 490 530 Color Reproduction [%] 81.6 100 Color Reproduction [ % ] 79.3 79.3 78.3

Hereinafter, the present invention will be described in more detail with reference to Production Examples and Examples. It is to be understood that the following Preparation Examples and Examples are for the purpose of illustration only and are not intended to limit the scope of the present invention.

[Manufacturing Example]

Coating layer Manufacturing example

20 wt% of the YAG-based fluorescent material (Y3A15012: Ce3 +) and 2 wt% of LuAG-based fluorescent material (Lu3Al5O12: Ce3 +) are mixed and put into a polymer matrix and stirred for 60 minutes. The polymer matrix was NSP53 in Nc chem. And NSP 53 in NSP52. Two kinds of photoinitiators are added to the stirred mixture of the phosphor and the matrix. As the photoinitiator, 5 wt% of IG 184 and 2 kinds of TPO were mixed at a ratio of 5: 5.

After coating the thus prepared coating solution on one side of the PET film, the engraved pattern is lapped, and after pre-curing by using a 260 nm-UV lamp, the engraved pattern is removed.

The pattern is applied for about 5 seconds using a non-electrode lamp to the pattern to which the phosphor with the engraved pattern is removed. The amount of light irradiated at this time is preferably 1000 mj or less.

[Example]

Example

A light guide plate 16, a high brightness film 100 having a pattern portion, a DBEF 14 and a liquid crystal panel 15 are sequentially disposed in front of a blue LED 110 as a light source, LCD.

[Comparative Example]

Comparative Example  One

LCD was manufactured in the same manner as in Example except that DBEF (14) was omitted.

The luminance and viewing angle of the LCD manufactured according to the above-described Example and Comparative Example 1 were measured, and the results are shown in FIG. 4 and Table 9.

division Example Comparative Example 1 Brightness (nit) 784.7 559.3

As shown in Table 6, it can be seen that the brightness enhancement effect is obtained when applying the high brightness film of the present invention to the quantum dot TV (brightness 100%), and when the DBEF and the high brightness film are applied together (Example) It can be confirmed that it is maximized.

It can also be seen from FIG. 3 that by applying DBEF and a high-luminance film together, excellent luminance characteristics can be ensured over the entire viewing angle range.

In addition, FIG. 4 shows that both the viewing angle and the luminance are excellent in the embodiment, and in the comparative example 1, when the DBEF is not used, the viewing angle falls sharply in the range of 30 to 45 degrees or -35 to -45 degrees.

The present invention may further include a back coating layer on at least one of the DBEF and the high brightness film.

By the particles included in the back coating, irregularities are provided on the back surface of the optical film to prevent blocking with other optical sheets to improve workability and to prevent static electricity caused by friction in the process.

The coating solution used for the back coating is composed of urethane acrylate oligomer, monofunctional monomer, photoinitiator, leveling agent, dispersant, and PMMA particles.

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 amount is less than 0.1 wt%, sufficient irregularities can not be formed on the back surface of the optical film. When the amount exceeds 5 wt%, transmitted light loss due to a high haze occurs. Therefore, the haze of the back coating layer is adjusted to 1 to 20% .

An anti-static additive may be added to the back coat as needed. The surface resistivity can be controlled by adding the antistatic agent. The antistatic agent is preferably contained in an amount of 0.01 to 3 wt% based on the total amount of the back coat layer. When the content of the antistatic agent is less than 0.01 wt%, the surface resistance for preventing static electricity is insufficient. When the antistatic agent content is more than 3 wt%, an excessive amount of the antistatic agent is added excessively. As a result, an antistatic agent is added in an amount of 0.01 to 3 wt% 10 ¹⁰ to 10 ¹² Ohm / □. When the surface resistance is in the range of 10 ¹⁰ to 10 ¹² Ohm / □, 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 is immediately attenuated.

Back coating can be done by bar coating or slot-die coating.

The thickness of the coating layer upon back coating is preferably 1 to 10 mu m. When the thickness is less than 1 占 퐉, sufficient irregularities are not formed on the back surface of the optical film, preventing blocking. On the other hand, when the thickness is more than 10 占 퐉, there is a problem of transmission light loss due to high haze.

The present invention can form a composite sheet for a liquid crystal display by adhering a plurality of films constituting an LCD in the form of a composite sheet. That is, a high-brightness film (HBF) and other optical films are laminated with an adhesive to form a composite sheet, which can be applied to an LCD.

The optical film may be selected from at least one of a prism sheet, a DBEF, and a viewing angle supplement sheet (lens film, MOP, diffusion sheet).

The adhesive preferably uses a transparent adhesive (OCA), and 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.

The lamination is performed by the same process as shown in FIG. The optical film F1 is supplied through the first supply roller R1 and the high luminance film F2 is supplied through the second supply roller R2. The optical film F1 passes through the adhesive application roller R3 and is coated on at least one surface of the optical film with an adhesive A and is then joined to the high-luminance film F2 through the jersey roller R4 to form a composite sheet F3 ) Is completed.

When two or more optical films are selected and used, a high-luminance film and one optical film are first laminated by the above process, and then the remaining one optical film is sequentially laminated by repeating the above- To form a sheet.

In the present invention, a high-brightness film (100) and a DBEF (14) are laminated by a lamination process to form a single composite sheet composed of a high luminance film and DBEF. Specifically, the composite sheet can be formed by applying an adhesive between the high-luminance film and the optical film.

When the composite sheet of the present invention is formed, it is preferable to form a back coating layer by performing back coating on a high luminance film.

How to measure luminance

The brightness and color reproducibility of the brightness enhancement film of the present invention were evaluated using a liquid crystal display and a BM-7FAST color luminance meter from Topcon. The liquid crystal display device actually used is UN55JS8500F (Samsung, 55-inch Blue-BLU), and its basic configuration is as follows. An edge-type blue LED light source, a light guide plate, a double brightness enhancement film (DBEF), and a liquid crystal panel. In this apparatus, the high luminance film (HBF) of the present invention is placed between the light guide plate and the DBEF to evaluate the luminance and color reproducibility. In the evaluation, the interval between the BM-7FAST apparatus and the liquid crystal display apparatus (UN55JS8500F) is kept constant at 50 cm.

11: white LED 12: diffusion plate
13: prism sheet 14: DBEF
15: liquid crystal panel 16: light guide plate
100: a high luminance film (HBF)
110: light source 120: barrier film
130: Quantum dot layer 140: Base film
150: phosphor
R1: first supply roller
R2: second supply roller
R3: Adhesive application roller
R4: Lap roller
R5: take-up roller
r: Guide roller
A: Adhesive
F1: Optical film
F2: High Brightness Film (HBF)
F3: Composite sheet

Claims (15)

(YAG) phosphor and a LuAG-based phosphor is coated on a base film, and the coating layer further comprises DBEF in a high-luminance film having a pattern portion formed thereon, wherein the YAG-base phosphor is Ca3 (Sc, Mg) 2Si3O12: Ce3 + or Y3Mg2AlSi2O12: Ce3 +, wherein the LuAG-based phosphor is Lu2CaMg2Si3O12: Ce3 +, and the YAG-based phosphor is 10 to 40 wt% and the LuAG-based phosphor is 1 to 20 wt% with respect to the whole coating layer.
delete The liquid crystal display device according to claim 1, wherein the thickness of the coating layer is 10 to 100 占 퐉.
delete delete The patterning apparatus according to claim 1, wherein the pattern portion is a triangular-pyramidal, quadrangular-pyramidal, hemispherical,

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A base film is coated with a coating layer containing a YAG-base phosphor and a LuAG-base phosphor, and the coating layer is formed by laminating a high-brightness film and a DBEF having a pattern formed thereon with an adhesive, wherein the YAG base phosphor is Ca3 (Sc, Mg) 2Si3O12: Ce3 + or Y3Mg2AlSi2O12: Ce3 +, wherein the LuAG-based phosphor is Lu2CaMg2Si3O12: Ce3 +, and the YAG-based phosphor and the LuAG-based phosphor are contained in an amount of 10 to 40 wt% and 1 to 20 wt%, respectively. delete 13. The composite sheet for a liquid crystal display device according to claim 12, wherein the thickness of the coating layer is 10 to 100 mu m. 13. The composite sheet for a liquid crystal display device according to claim 12, wherein the high brightness film comprises a back coating layer comprising PMMA particles or PMMA particles and an antistatic agent.

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