KR101986005B1 - Color change sheet and backlight unit including the same - Google Patents

Abstract

The present invention relates to a light emitting device comprising a barrier layer, a first wavelength conversion layer formed on a lower surface of the barrier layer and including a green organic phosphor dispersed in a first resin matrix, and a second wavelength conversion layer formed on the upper surface of the barrier layer, And a second wavelength conversion layer including a red organic phosphor dispersed therein.

Description

COLOR CHANGE SHEET AND BACKLIGHT UNIT INCLUDING THE SAME BACKGROUND OF THE INVENTION [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color conversion sheet and a backlight unit including the color conversion sheet, and more particularly, to a color conversion sheet having less color change and excellent reliability and a backlight unit including the same.

2. Description of the Related Art A liquid crystal display (LCD) is a light-receiving type display device in which a light is emitted from the outside without forming an image by itself to form an image. Therefore, a backlight unit (BLU) for emitting light is disposed on the back surface of the liquid crystal display device.

Particularly, quantum dot technology has recently been applied to realize a high image quality of a liquid crystal display device. The quantum dot technology has advantages in that it can realize various colors only by controlling the size of nano-inorganic particles and has excellent stability against light such as UV.

However, existing cadmium (Cd) nano-inorganic particles are environmentally problematic, and nanoparticle particles are vulnerable to moisture and must be used together with barrier film, resulting in poor price competitiveness.

Recently, organic phosphors capable of realizing high color reproducibility and excellent luminance characteristics without containing cadmium nano-inorganic particles have been developed.

SUMMARY OF THE INVENTION The present invention provides a color conversion sheet which is environmentally safe by applying an organic phosphor and has excellent color reproducibility and luminance characteristics as well as low color change in various environments and is excellent in reliability and a backlight unit including the color conversion sheet. .

According to an embodiment of the present invention, there is provided an organic light emitting display comprising a barrier layer, a first wavelength conversion layer formed on a lower surface of the barrier layer and including a green organic fluorescent material dispersed in a first resin matrix, And a second wavelength conversion layer formed on the upper surface of the first resin matrix and including a red organic phosphor dispersed in the second resin matrix.

And a base layer formed on at least one side of the first wavelength conversion layer and the second wavelength conversion layer in contact with the outside.

The barrier layer may be a flexible polymer film having a visible light transmittance of 70% or more.

Wherein the first resin matrix and the second resin matrix are selected from the group consisting of an ester, an olefin, an acryl, an ether, a urethane, a carbonate, and an imide ) ≪ / RTI > resin.

The acid value of the first resin matrix and the second resin matrix may be 0 to 20 mgKOH / g, and the hydroxyl value may be 0 to 30 mgKOH / g.

The resin included in the first resin matrix and the second resin matrix may have a number average molecular weight (Mn) of 1,000 to 50,000 g / mol or a weight average molecular weight (Mw) of 50,000 to 2,000,000 g / mol.

The barrier layer may have a thickness ranging from 0.1 to 200 mu m.

The first wavelength conversion layer and the second wavelength conversion layer may have a thickness ranging from 1 to 150 mu m.

The green organic fluorescent material may include 0.001 to 10 parts by weight based on 100 parts by weight of the solid content of the first resin matrix, and the red organic fluorescent material may include 0.0001 to 5 parts by weight based on 100 parts by weight of the solid content of the second resin matrix. have.

The adhesive force between the barrier layer and the first and second wavelength conversion layers may be 50 gf / inch or more.

According to another embodiment of the present invention, there is provided a color conversion sheet comprising a light source, a color conversion sheet spaced from the light source to convert light incident from the light source into white light, a light guide plate positioned between the light source and the color conversion sheet, Wherein the color conversion sheet comprises a barrier layer, a first wavelength conversion layer formed on a lower surface of the barrier layer and including a green organic fluorescent material dispersed in a first resin matrix, And a second wavelength conversion layer formed on the upper surface of the layer and including a red organic phosphor dispersed in the second resin matrix.

And a base layer formed on at least one side of the first wavelength conversion layer and the second wavelength conversion layer in contact with the outside.

The barrier layer may be a flexible polymer film having a visible light transmittance of 70% or more.

Wherein the first resin matrix and the second resin matrix are selected from the group consisting of an ester, an olefin, an acryl, an ether, a urethane, a carbonate, and an imide ), Wherein the acid value of the first resin matrix and the second resin matrix is 0 to 20 mgKOH / g, the hydroxyl value is 0 to 30 mgKOH / g, The first resin matrix and the resin included in the second resin matrix may have a number average molecular weight (Mn) of 1,000 to 50,000 g / mol or a weight average molecular weight (Mw) of 50,000 to 2,000,000 g / mol.

According to the color conversion sheet and the backlight unit including the color conversion sheet according to the embodiment of the present invention, the organic phosphor is applied to the color conversion sheet to provide an environmentally safe, high color reproducibility and luminance characteristics, And the reliability is excellent.

1 is a cross-sectional view of a color conversion sheet according to an embodiment of the present invention.
2 is a schematic view of a backlight unit including a color conversion sheet according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: FIG. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the drawings, the thickness is enlarged to clearly represent the layers and regions. Like parts are designated with like reference numerals throughout the specification. It will be understood that when an element such as a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the element directly over another element, Conversely, when a part is "directly over" another part, it means that there is no other part in the middle.

Next, a color change sheet according to an embodiment of the present invention will be described with reference to FIG.

1 is a cross-sectional view of a color conversion sheet according to an embodiment of the present invention.

Referring to FIG. 1, the color conversion sheet 10 according to an embodiment of the present invention includes a barrier layer 24, a barrier layer 24 formed on the lower surface of the barrier layer 24, The first wavelength conversion layer 22 including the organic fluorescent material 15 and the second organic material including the red organic fluorescent material 13 formed on the upper surface of the barrier layer 24 and dispersed in the second resin matrix 19b. And a wavelength conversion layer 20.

At least one surface of the first wavelength conversion layer 22 and the second wavelength conversion layer 20 that is in contact with the outside may further include a base layer 17 as needed.

Hereinafter, each configuration will be described in detail.

The barrier layer 24 may be a thermoplastic resin having a visible light transmittance of 70% or more, a thermosetting resin, a UV curable resin, or the like, but is not limited to this, and may be a transparent, flexible, It is possible to prevent mixing of the organic phosphors 15 and 13 and the resin matrix 19 with the organic phosphors 15 and 13 and the resin matrix 19 of the other wavelength conversion layers 22 and 20, Applicable.

The barrier layer 24 may be formed of a polymer such as polyethylene terephthalate, polyethylene naphthalate, polyacrylate, polycarbonate, polyetherimide, polyimide, Film.

The barrier layer 24 may be 0.1 to 200 탆 thick, preferably 1 to 150 탆 thick.

This is because when the thickness of the barrier layer 24 is less than 0.1 탆, it is difficult to control the color change that may occur due to the diffusion or mixing of the organic phosphors 13 and 15 or the resin matrix 19 depending on the temperature, This is because transmission of light can be inhibited.

The first wavelength conversion layer 22 formed on the lower surface of the barrier layer 24 may include the green organic phosphor 15 dispersed in the first resin matrix 19a.

The first resin matrix 19a may contain at least one of an ester, an olefin, an acryl, an ether, a urethane, a carbonate, and an imide resin It is possible to fix the green organic phosphor 15 and prevent exposure to moisture or oxygen so that decomposition of the green organic phosphor 15 dispersed in the first resin matrix 19a is prevented .

The resin included in the first resin matrix 19a may have a number average molecular weight (Mn) of 1,000 to 50,000 g / mol or a weight average molecular weight (Mw) of 50,000 to 2,000,000 g / mol.

This is because when the number average molecular weight of the resin contained in the first resin matrix 19a is less than 1,000 g / mol or the weight average molecular weight is less than 50,000 g / mol, tackiness of the first resin matrix 19a occurs, When the number average molecular weight is more than 50,000 g / mol or the weight average molecular weight is more than 2,000,000 g / mol, the first resin matrix (19a) may have solubility in solvents This is because the first wavelength conversion layer 22 may be difficult to form.

The acid value of the resin contained in the first resin matrix 19a may be 0 to 20 mgKOH / g and the hydroxyl value may be 0 to 30 mgKOH / g, preferably 0 to 20 mgKOH / g Lt; / RTI >

It can be generally used as a resin matrix of a wavelength conversion layer included in a color conversion sheet, such as an ester, an olefin, an acryl, an ether, a urethane, a carbonate carbonate and imide resins accelerate the decomposition of organic phosphors in which functional groups such as hydroxyl or carboxylic acid groups present in these resins are dispersed in the resin matrix, thereby lowering the reliability of the organic phosphors.

The ester-based resin, which is one of the resins that can be used as the first resin matrix 19a, may include an ester-based resin polymerized from an aliphatic polyhydric alcohol and an aliphatic or aromatic polybasic acid.

Here, the aliphatic polyhydric alcohol may include at least one of aliphatic compounds having 2 or more hydroxyl groups and 2 to 10 carbon atoms, for example, ethylene glycol, propanediol, butanediol, neopentyl glycol and trimethylol propane have.

The aliphatic polyvalent acid may include at least one of malonic acid, succinic acid, adipic acid and sebacic acid as an aliphatic compound having 2 or more carboxylic acid groups and having 2 to 12 carbon atoms, An aromatic compound having two or more carboxylic acid groups and having 1 to 4 aromatic rings, for example, at least one of isophthalic acid, phthalic acid, terephthalic acid and cyclohexyldicarboxylic acid.

Examples of the first resin matrix 19a include polyester, modified polyester, polyethylene, polycycle olefin, poly (methyl) methacrylate, Polyethylene glycol, polyurethane, polycarbonate, polyimide, and block copolymers thereof. The term " polyolefin "

The first resin matrix 19a may further include a cross-linking agent for chemical cross-linking of the first resin matrix 19a, if necessary.

The crosslinking agent may include an isocyanate, an amine, an acid anhydride, a thiol, an epoxy crosslinking agent, and the like. However, the crosslinking agent is not limited thereto, and various crosslinking agents May be included.

The green organic fluorescent substance 15 dispersed in the first resin matrix 19a of the first wavelength conversion layer 22 can emit green light by absorbing blue light.

The green organic phosphor 15 is a compound or a derivative thereof having a condensed aryl ring such as naphthalene, anthracene, phenanthrene, pyrene, chrysene, triphenylene, perylene, fluoranthene, fluorene, Diphenylanthracene or 5,6,11,12-tetraphenylnaphthacene), furan, pyrrole, thiophene, silole, 9-silafluorene, Benzothiophene, indole, dibenzothiophene, dibenzofuran, imidazopyridine, phenanthroline, pyridine, pyrazine, naphthyridine, quinoxaline, pyrrolopyridine , A compound having a heteroaryl ring such as thioxanthone or a derivative thereof, a borane derivative, a distyrylbenzene derivative, 4,4'-bis (2- (4-diphenylaminophenyl) ethenyl) biphenyl, Aminostyryl derivatives such as bis (N- (stilben-4-yl) -N-phenylamino) stilbene, aromatic acetylene derivatives, tetraphenylbutadiene derivatives, 3,4-c] pyrrole derivatives, 2,3,5,6-1H, 4H-tetrahydro-9- (2'-benzothiazolyl) quinolinone derivatives, pyrimidine derivatives, Coumarin derivatives such as imidazole, thiazole, thiadiazole, carbazole, oxazole, oxadiazole, triazole, and metal complexes thereof and N, N Aromatic amine derivatives represented by '-diphenyl-N, N'-di (3-methylphenyl) -4,4'-diphenyl-1,1'-diamine, and the like.

Further, the green organic fluorescent substance 15 may include a compound represented by the following general formula (1).

The green organic phosphor 15 may include 0.001 to 10 parts by weight, preferably 0.001 to 1 part by weight, based on 100 parts by weight of the solid content of the first resin matrix 19a.

If the green organic phosphor 15 is contained in an amount of less than 0.001 part by weight, the color conversion effect of the color conversion sheet 10 to a desired color may be insufficient. If the green organic phosphor 15 is contained in an amount exceeding 10 parts by weight, 15) may cause quenching phenomenon due to interaction such as aggregation.

The thickness of the first wavelength conversion layer 22 including the green organic phosphor 15 dispersed in the first resin matrix 19a may be 1 to 150 占 퐉, and preferably 5 to 100 占 퐉.

Next, the second wavelength conversion layer 20 formed on the upper surface of the barrier layer 24 may include the red organic phosphor 13 dispersed in the second resin matrix 19b.

That is, the barrier layer 24 may be located between the first wavelength conversion layer 22 and the second wavelength conversion layer 20. [

The second resin matrix 19b is the same as the first resin matrix 19a described above, and redundant description is omitted.

The red organic phosphor 13 dispersed in the second resin matrix 19b of the second wavelength conversion layer 20 can emit red light by absorbing blue light or green light.

The red organic phosphor 13 is a compound or a derivative thereof having a condensed aryl ring such as naphthalene, anthracene, phenanthrene, pyrene, chrysene, triphenylene, perylene, fluoranthene, fluorene, Diphenylanthracene or 5,6,11,12-tetraphenylnaphthacene), furan, pyrrole, thiophene, silole, 9-silafluorene, Benzothiophene, indole, dibenzothiophene, dibenzofuran, imidazopyridine, phenanthroline, pyridine, pyrazine, naphthyridine, quinoxaline, pyrrolopyridine , A compound having a heteroaryl ring such as thioxanthone or a derivative thereof, a borane derivative, a distyrylbenzene derivative, 4,4'-bis (2- (4-diphenylaminophenyl) ethenyl) biphenyl, Aminostyryl derivatives such as bis (N- (stilben-4-yl) -N-phenylamino) stilbene, aromatic acetylene derivatives, tetraphenylbutadiene derivatives, 3,4-c] pyrrole derivatives, 2,3,5,6-1H, 4H-tetrahydro-9- (2'-benzothiazolyl) quinolinone derivatives, pyrimidine derivatives, Coumarin derivatives such as imidazole, thiazole, thiadiazole, carbazole, oxazole, oxadiazole, triazole, and metal complexes thereof and N, N Aromatic amine derivatives represented by '-diphenyl-N, N'-di (3-methylphenyl) -4,4'-diphenyl-1,1'-diamine, and the like.

Further, the red organic phosphor 13 may include a compound represented by the following general formula (2).

The red organic phosphor 13 may include 0.0001 to 5 parts by weight, preferably 0.0001 to 1 part by weight, based on 100 parts by weight of the solid content of the second resin matrix 19b.

If the red organic phosphor 13 is contained in an amount of less than 0.0001 part by weight, color conversion effect to a desired color may be insufficient through the color conversion sheet 10, and if it exceeds 5 parts by weight, red organic phosphor 13) may cause quenching phenomenon due to the interaction such as aggregation.

The thickness of the second wavelength conversion layer 20 including the red organic phosphor 13 dispersed in the second resin matrix 19b may be 1 to 150 탆, preferably 1 to 100 탆.

As a result, the first wavelength conversion layer 22 and the second resin matrix 19b, which are respectively disposed on both sides of the barrier layer 24 and include the green organic fluorescent substance 15 dispersed in the first resin matrix 19a, The color conversion sheet 10 according to the embodiment of the present invention including the second wavelength conversion layer 20 including the red organic phosphor 13 dispersed therein can convert blue light into white light and emit the blue light.

The adhesive force between the barrier layer 24 of the color conversion sheet 10 and the wavelength conversion layers 22 and 20 according to the embodiment of the present invention may be 50 gf / inch or more.

This is because it is difficult to fix the laminated structure of the color conversion sheet 10 when the adhesive force is less than 50 gf / inch.

The wavelength conversion layers 22 and 20 and the barrier layer 24 of the color conversion sheet 10 according to the embodiment of the present invention have different refractive indices from each other. For example, when the light finally emitted to the incident light is the second wavelength The refractive index of the barrier layer 24 is greater than the refractive index of the second wavelength conversion layer 20 when the light is emitted through the conversion layer 20 and conversely the light finally emitted to the incident light is emitted through the first wavelength conversion layer 22 The refractive index of the barrier layer 24 is larger than that of the first wavelength conversion layer 22.

That is, the refractive index of the barrier layer 24 of the color conversion sheet 10 according to the embodiment of the present invention may be larger than the refractive index of the wavelength conversion layers 22 and 20.

This is because it is possible to increase the light reflectance of the barrier layer 24 and effectively emit color-converted light to the outside.

In the case of a commonly used color conversion sheet, the green organic phosphor 15 and the red organic phosphor 13 are dispersed together in the resin matrix 19 composed of one layer, or the resin matrix containing the green organic phosphor 15 (19) layer and the red organic phosphor (13) are in contact with each other to form a plurality of layers.

At this time, as the distance from the green organic phosphor 15 to the red organic phosphor 13 becomes shorter, the green light can be absorbed more easily and the efficiency of red light emission can be increased, and the color conversion including the same content of the organic phosphors 13, It is possible to realize various white light by controlling the distance of the organic phosphors 13 and 15 in the sheet.

Here, when the green organic phosphor 15 and the red organic phosphor 13 are included together in the resin matrix composed of one layer, the distance between the green organic phosphor 15 and the red organic phosphor 13 is relatively close to the surrounding environment, For example, the distance between them may vary relatively due to the influence of the high temperature or high humidity environment. This may change the luminous efficiency of the red organic phosphor 13 so that the color coordinates of the white light, which ultimately can be converted by the color conversion sheet, Change or reduce reliability.

On the other hand, when the resin matrix layer including the green organic fluorescent substance 15 and the resin matrix layer including the red organic fluorescent substance 13 are in contact with each other to form a plurality of layers, The green or red organic phosphor existing at the interface can be diffused to the interface of the other layer so that the distance between the red organic phosphor 13 and the green organic phosphor 15 is shortened so that the luminous efficiency of the red organic phosphor 13 is changed Thereby changing the color coordinates of the white light or lowering the reliability.

A color conversion sheet 10 according to an embodiment of the present invention includes a first wavelength conversion layer 22 including a green organic fluorescent material 15 and a second wavelength conversion layer 20 including a red organic fluorescent material 13, The first and second wavelength conversion layers 22 and 20 are completely separated from each other by arranging the barrier layer 24 between the green organic fluorescent material 15 and the red organic fluorescent material 13, The luminous efficiency of the red organic phosphor 13 can be kept constant and thus the color coordinates and reliability of the white light emitted by the color conversion sheet 10 can be prevented from lowering.

That is, by arranging the barrier layer 24, the color conversion sheet 10 according to the embodiment of the present invention can prevent the green and red organic phosphors 15, 13 (included in the first and second wavelength conversion layers 22, And the resin matrix 19 are prevented from diffusing or mixing with each other, thereby achieving high color uniformity and uniform brightness even in a high temperature and high humidity environment.

Next, at least one side of the first wavelength conversion layer 22 and the second wavelength conversion layer 20, which are in contact with the outside, may further include base layers 17a and 17b as required.

The substrate layers 17a and 17b may be transparent and flexible polymer films and may be formed of any suitable material such as polyethylene terephthalate, polyethylene naphtalate, polyacrylate, polycarbonate polycarbonate, polyetherimide, and polyimide. However, the present invention is not limited thereto, and various polymer films may be used.

The base layers 17a and 17b may be optical films such as a diffusion sheet and a prism sheet, but the present invention is not limited thereto and a sheet having various functions can be applied.

Next, a backlight unit including a color conversion sheet according to an embodiment of the present invention will be described with reference to FIG.

2 is a schematic view of a backlight unit including a color conversion sheet according to an embodiment of the present invention.

A backlight unit 90 according to an embodiment of the present invention includes a light source 70, a reflector 50 that reflects light emitted from the light source 70 to increase light efficiency, a reflector 50 that is positioned above the reflector 50, 70 and the color conversion sheet 10 located above the light guide plate 30. The color conversion sheet 10 may be a light guide plate,

Although FIG. 3 illustrates the edge type light source 70 for the sake of convenience, the light source 70 may be applied in various forms such as a side chain type or direct type.

The same color conversion sheet as that described in the embodiment shown in Figs. 1 and 2 is applied to the color conversion sheet 10, and a duplicate description will be omitted.

The color conversion sheet 10 may further include at least one or more optical sheets such as a diffusion sheet, a prism sheet, a brightness enhancement film (DBEF), and the like.

Hereinafter, the structure and effect of the present invention will be described in more detail with reference to examples and comparative examples. However, this embodiment is intended to explain the present invention more specifically, and the scope of the present invention is not limited to these embodiments.

Example 1

The green organic phosphor containing the compound represented by Formula 1 and the red organic phosphor containing the compound represented by Formula 2 were dissolved in a methyl ethyl ketone solvent to prepare a green organic phosphor solution and a red organic phosphor solution.

The prepared green organic phosphor solution was mixed with a polyester resin (ARAKAWA, 2624A) having an acid value of 12 mg KOH / g and a hydroxyl value of 5 mg KOH / g, and methyl ethyl ketone was added thereto so as to have a viscosity of 150 cps. After stirring at 150 rpm for 30 minutes, Wavelength conversion layer composition was prepared.

At this time, the green organic fluorescent material was added in an amount of 0.36 parts by weight based on 100 parts by weight of the solid content of the polyester resin.

The prepared red organic phosphor solution was mixed with an acrylic resin (Samhwa Paint, SA3000), and methyl ethyl ketone was added thereto so as to have a viscosity of 150 cps, followed by stirring at 150 rpm for 30 minutes to prepare a second wavelength conversion layer composition.

At this time, the red organic phosphor was 0.03 parts by weight based on 100 parts by weight of the solid content of the acrylic resin.

A first wavelength conversion layer composition was bar-coated on the top surface of a polyethylene terephthalate film (TAK, PL2) and then dried at 120 ° C for 2 minutes to form a first wavelength conversion layer with a thickness of 20 μm.

Next, a 100 탆 thick polyethylene terephthalate film (TAK, PL2) was laminated on the upper surface of the first wavelength conversion layer, and then a barrier layer was formed using a roll laminate (GMP, EXCELAM II-355Q).

The second wavelength conversion layer composition was coated on the opposite surface of the diffusion layer of the diffusion film (TAK, TDF12C) by bar coating and dried at 120 DEG C for 2 minutes to form a second wavelength conversion layer having a thickness of 20 mu m.

Thereafter, the barrier layer and the second wavelength conversion layer were laminated so as to be in contact with each other, and then a color conversion sheet was prepared using roll laminate (GMP, EXCELAM II-355Q).

Example 2

Except that a polyester resin obtained by dissolving a polyester (TOYOBO, Vylon 630) having an acid value of 2 mgKOH / g or less and a hydroxyl value of 5 mgKOH / g in methyl ethyl ketone was used in place of the acrylic resin of the second wavelength conversion layer composition. A color conversion sheet was prepared in the same manner.

Example 3

A polyester resin (SK Chemical, Es-110) having an acid value of 3 mgKOH / g or less and a hydroxyl value of 2 to 6 mgKOH / g was dissolved in methyl ethyl ketone instead of the polyethylene terephthalate film (TAK, PL2) A color conversion sheet was prepared in the same manner as in Example 1 except that the upper surface of the first wavelength conversion layer was bar coated and then dried at 120 ° C. for 2 minutes to laminate a transparent polymer resin layer having a thickness of 10 μm .

Comparative Example 1

A color conversion sheet was prepared in the same manner as in Example 1, except that the process of forming the barrier layer was omitted.

Comparative Example 2

A color conversion sheet was prepared in the same manner as in Example 2, except that the process of forming the barrier layer was omitted.

Experimental Example 1: Measurement of luminance and color coordinate change

The initial luminance (L) and the color coordinate (x, y) values of the color conversion sheets of Examples 1 to 3 and Comparative Examples 1 and 2 were measured and then the color coordinate change with time elapsed at 60 ° C. and 90% (Δx, Δy) and luminance change (ΔL) were measured using a spectral radiation luminance meter (CA-S20W, KONICA MINOLTA). The results are shown in Table 1 below.

At this time, the color conversion sheet was laminated on the upper surface of the light guide plate of the backlight unit including the blue LED having the wavelength of 450 nm, and the prism sheet was further laminated on the upper surface of the color conversion sheet.

High temperature and high humidity treatment time 0 Hr 96 Hr 312 Hr Example 1 ΔL
(Measured value / initial value) 100% 103.6% 101.4% Δx, Δy
(Measured value - initial value) 0, 0 +0.0004, +0.0008 -0.0002, +0.0002 Example 2 ΔL
(Measured value / initial value) 100% 101.7% 102.4% Δx, Δy
(Measured value - initial value) 0, 0 +0.0002, +0.0004 +0.0003, +0.0006 Example 3 ΔL
(Measured value / initial value) 100% 102.7% 103.8% Δx, Δy
(Measured value - initial value) 0, 0 -0.0003, +0.0017 -0.0004, +0.0013 Comparative Example 1 ΔL
(Measured value / initial value) 100% 96.8% 96.2% Δx, Δy
(Measured value - initial value) 0, 0 -0.0015, -0.0052 -0.0010, -0.0060 Comparative Example 2 ΔL
(Measured value / initial value) 100% 95.3% 95.1% Δx, Δy
(Measured value - initial value) 0, 0 +0.0046, +0.0001 +0.0063, -0.0017

As shown in Table 1, in the case of the color conversion sheet of Comparative Examples 1 and 2 in which the barrier layer is omitted, color and brightness change largely occur in an environment of high temperature and high humidity, whereas in Examples 1 to 3 It was confirmed that the color conversion sheet had little change in color and luminance even in a high temperature and high humidity environment.

Experimental Example 2: Measurement of adhesion between barrier layer and wavelength conversion layer

In order to measure the adhesion between the barrier layer and the wavelength conversion layer in the color conversion sheets of Examples 1 to 3, one side of the polyethylene terephthalate film laminated on the first wavelength conversion layer was fixed to the SUS plate and fixed, LLOYD, and L / F Plus) was peeled from the polyethylene terephthalate film at a peeling speed of 300 mm / min at 25 DEG C to peel the polyethylene terephthalate film at 90 degrees to measure the adhesive strength. The measurement results are shown in Table 2 Respectively.

Example 1 Example 2 Example 3 Peeling The interface between the first wavelength conversion layer and the color change prevention layer The interface between the first wavelength conversion layer and the color change prevention layer The interface between the second wavelength conversion layer and the color change prevention layer adhesiveness
(gf / inch) 351 338 643

As shown in Table 2, it was confirmed that adhesion between the barrier layer and the wavelength conversion layer of Examples 1 to 3 was 50 gf / inch or more.

As described above, according to the color conversion sheet and the backlight unit of the embodiment of the present invention, the organic phosphor is applied to the color conversion sheet to provide environmentally safe, excellent color reproducibility and luminance characteristics, Reliability is excellent.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

10: color conversion sheet 22: first wavelength conversion layer
15: green organic phosphor 19a: first resin matrix
24: barrier layer 20: second wavelength conversion layer
13: red organic fluorescent material 19b: second resin matrix
90: backlight unit 30: light guide plate
70: light source 50: reflector

Claims (14)

Barrier layer,
A first wavelength conversion layer formed on a lower surface of the barrier layer and including a green organic fluorescent material dispersed in a first resin matrix,
And a second wavelength conversion layer formed on an upper surface of the barrier layer and including a red organic phosphor dispersed in a second resin matrix,
Wherein the barrier layer maintains a distance between the green organic phosphor of the first wavelength conversion layer and the red organic phosphor of the second wavelength conversion layer,
The barrier layer prevents the organic phosphors or the resin matrix of the first wavelength conversion layer and the second wavelength conversion layer from being mixed with different wavelength conversion layers,
Wherein the barrier layer has a refractive index larger than that of any one wavelength conversion layer in which light is finally emitted from the first wavelength conversion layer and the second wavelength conversion layer with respect to incident light,
Wherein the barrier layer has a thickness of 0.1 to 200 mu m. The method of claim 1,
And a base layer formed on at least one side of the first wavelength conversion layer and the second wavelength conversion layer in contact with the outside. The method of claim 1,
Wherein the barrier layer is a flexible polymer film having a visible light transmittance of 70% or more. 4. The method of claim 3,
Wherein the first resin matrix and the second resin matrix are selected from the group consisting of an ester, an olefin, an acryl, an ether, a urethane, a carbonate, and an imide ) Resin. ≪ / RTI > 5. The method of claim 4,
Wherein the first resin matrix and the second resin matrix have an acid value of 0 to 20 mgKOH / g and a hydroxyl value of 0 to 30 mgKOH / g. 5. The method of claim 4,
Wherein the resin contained in the first resin matrix and the second resin matrix has a number average molecular weight (Mn) of 1,000 to 50,000 g / mol or a weight average molecular weight (Mw) of 50,000 to 2,000,000 g / mol. delete 4. The method of claim 3,
Wherein the first wavelength conversion layer and the second wavelength conversion layer have a thickness ranging from 1 to 150 mu m. 4. The method of claim 3,
Wherein the green organic fluorescent material comprises 0.001 to 10 parts by weight based on 100 parts by weight of the solid content of the first resin matrix,
Wherein the red organic phosphor comprises 0.0001 to 5 parts by weight based on 100 parts by weight of the solid content of the second resin matrix. The method of claim 1,
Wherein the adhesive force between the barrier layer and the first and second wavelength conversion layers is 50 gf / inch or more. Light source,
A color conversion sheet provided so as to be spaced apart from the light source to convert light incident from the light source into white light,
A light guide plate positioned between the light source and the color conversion sheet,
And a reflector positioned under the light guide plate,
Wherein the color conversion sheet comprises a barrier layer, a first wavelength conversion layer formed on a lower surface of the barrier layer and including a green organic fluorescent material dispersed in a first resin matrix, and a second wavelength conversion layer formed on an upper surface of the barrier layer, And a second wavelength conversion layer including a red organic phosphor dispersed in the matrix,
Wherein the barrier layer maintains a distance between the green organic phosphor of the first wavelength conversion layer and the red organic phosphor of the second wavelength conversion layer,
The barrier layer prevents the organic phosphors or the resin matrix of the first wavelength conversion layer and the second wavelength conversion layer from being mixed with different wavelength conversion layers,
Wherein the barrier layer has a refractive index larger than that of any one wavelength conversion layer in which light is finally emitted from the first wavelength conversion layer and the second wavelength conversion layer with respect to incident light,
Wherein the barrier layer has a thickness of 0.1 to 200 占 퐉. 12. The method of claim 11,
And a base layer formed on at least one side of the first wavelength conversion layer and the second wavelength conversion layer in contact with the outside. 12. The method of claim 11,
Wherein the barrier layer is a flexible polymer film having a visible light transmittance of 70% or more. 12. The method of claim 11,
Wherein the first resin matrix and the second resin matrix are selected from the group consisting of an ester, an olefin, an acryl, an ether, a urethane, a carbonate, and an imide ) ≪ / RTI > resin,
Wherein the acid value of the first resin matrix and the second resin matrix is 0 to 20 mgKOH / g, the hydroxyl value is 0 to 30 mgKOH / g,
Wherein the resin contained in the first resin matrix and the second resin matrix has a number average molecular weight (Mn) of 1,000 to 50,000 g / mol or a weight average molecular weight (Mw) of 50,000 to 2,000,000 g / mol.

Images