KR101770518B1 - Method for manufacturing light conversion composite, light conversion film, backlight unit and display device comprising the same - Google Patents

Abstract

The present invention relates to a resin composition comprising a matrix resin; And a quantum dot-polymer bead dispersed in the matrix resin. The quantum dot wave number at a peak point of a scattering intensity graph according to a wave number measured by Small Angle X-ray Scattering (wave number) q ^-1 a 0.0056Å to 0.045Å ^- relates to the ^first optical transformation composite material and a method of manufacturing the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for manufacturing a photo-conversion composite, a photo-conversion composite, a photo-conversion film, a backlight unit,

More particularly, the present invention relates to a photoconversion composite material capable of producing a photoconversion film having excellent luminescent efficiency and less deterioration of edge portions in a high temperature and high humidity environment, and a method of manufacturing the same ≪ / RTI >

In recent years, the display field has been rapidly developed in line with the information age. In response to this trend, a liquid crystal display (LCD) is widely used as a flat panel display (FPD) having advantages of thinning, light weight, , A plasma display panel (PDP), an electroluminescence display (ELD), and a field emission display (FED) have been introduced, and a conventional cathode ray tube (CRT) It is rapidly emerging as a substitute.

Among these, liquid crystal display devices are attracting attention as next-generation advanced display devices with low power consumption, high portability, and high value-added. A liquid crystal display device is a light-receiving type display device in which light can not be emitted by itself and light is incident from the outside to form an image, and therefore, a light source for providing light is indispensably required. Conventionally, a cold cathode fluorescent lamp (CCFL) has been mainly used as a light source of a liquid crystal display device. However, the cold cathode fluorescent lamp has problems in that it is difficult to ensure luminance uniformity when the device is made large, .

Therefore, in recent years, there has been a tendency to use a light emitting diode (LED) instead of a cold cathode fluorescent lamp as a light source of a liquid crystal display device. When a tri-color LED is used as a light source, a high color purity can be reproduced, and a high-quality image can be realized. However, the manufacturing cost is increased because the cost is very high. Accordingly, techniques for realizing white light by converting a blue light into a red light and a green light by using a blue light emitting diode which is relatively inexpensive as a light source and a light conversion film including a quantum dot (QD) have been proposed.

It is important that the quantum dots are uniformly dispersed in the matrix resin during the production of the photoconversion film using the quantum dots. When the quantum dots are aggregated, the light emitted from the light source undergoes a reabsorption process through the two or more quantum dots, Because. However, the quantum dots currently available on the market are mostly capped with a hydrophobic ligand or the like for the purpose of improving dispersibility, so that the kinds of the dispersible medium are extremely limited, and thus the kinds of resins usable for producing the film are extremely limited .

In addition, in the case of the photo-conversion films proposed so far, a barrier film is attached to the upper and lower surfaces of the film, but no separate barrier means is provided on the side surface of the film, There is a problem in that the quantum dots located at the center are oxidized. In order to prevent this, it is preferable to use a matrix resin having a low transmittance for oxygen and moisture. However, there is a problem in that quantum dots are not well dispersed in resins having such a durability and / or moisture permeability. In order to solve these problems, a technique has been proposed in which a matrix resin having a low speculative rate and / or moisture permeability is heated at high temperature and mixed with quantum dots. However, since quantum dots have a property of easily deteriorating at high temperatures, There is a problem that the efficiency is lowered.

Disclosure of the Invention The present invention has been made to solve the above problems and it is an object of the present invention to provide a photoconversion composite material which is free from the need for a high temperature process and developed so that quantum dots can be uniformly dispersed in various matrix resins, .

Another object of the present invention is to provide a light-converting film having excellent light-emitting efficiency and improved quantum dot deterioration characteristics at the edge portion using the above-described light-converting composite material, a backlight including the same, and a display device.

According to another embodiment, the present invention provides a method of manufacturing a quantum dot-polymer bead, comprising: preparing a quantum dot-polymer bead using a solvent volatilization method; Mixing the quantum dot-polymer beads and the matrix resin to form a mixed solution; And curing the mixed solution. The present invention also provides a method for producing a light-converting composite material.

According to another embodiment, the present invention provides a composition comprising a matrix resin; And a quantum dot-polymer bead dispersed in the matrix resin, wherein the light-conversion composite has a scattering intensity according to a wave number measured by Small Angle X-ray Scattering intensity) is a wave number (wave number) q of the peak point (peak point) of the graph to 0.045Å 0.0056Å ^{-1 -} provides a ^first optical transform composite.

The quantum dot-polymeric beads include a plurality of quantum dot-polymer units formed by aggregation, and the quantum dot-polymer unit includes a polymer in which a part of quantum dots and chains are combined with a surface of the quantum dots to form a coating layer.

According to another embodiment, the present invention provides a film comprising a first barrier film; A light conversion layer disposed on the first barrier film, the light conversion layer comprising a matrix resin and a quantum dot-polymer bead dispersed in the matrix resin, the light conversion layer being formed of a light conversion composite material; And a second barrier film disposed on the light conversion layer, wherein the light conversion layer has a scattering intensity according to a wave number measured by Small Angle X-ray Scattering, the wave number (wave number) of the graph of q ^-1 to the peak point 0.0056Å 0.045Å ^- provides ^one optical conversion film.

At this time, it is preferable that the length of damage of the edge of the photoconversion film is 10 mm or less at 60 ° C and 90% relative humidity, and the damage length is 2 mm or less.

According to another embodiment, the present invention is a backlight unit comprising a light source unit and a light conversion film comprising a plurality of light sources, the light conversion film comprising: a first barrier film; A light conversion layer disposed on the first barrier film, the light conversion layer comprising a matrix resin and a quantum dot-polymer bead dispersed in the matrix resin, the light conversion layer being formed of a light conversion composite material; And a second barrier film disposed on the light conversion layer, wherein the light conversion layer has a scattering intensity according to a wave number measured by Small Angle X-ray Scattering, the wave number (wave number) of the graph of q ^-1 to the peak point 0.0056Å 0.045Å ^- provides a display device including the backlight unit ¹ and it.

Since the quantum dots in the quantum dot-polymer beads are spaced apart from each other by a predetermined distance, the light-conversion composite produced according to the manufacturing method of the present invention can minimize the deterioration of the luminous efficiency caused by the quantum dot aggregation.

In addition, since the photo-conversion composite according to the present invention can use a resin having a low permeability and moisture permeability as a matrix resin, deterioration of the edge portion can be minimized when the photo-conversion film is produced using the resin.

In addition, since the light-converting composite material according to the present invention is produced at room temperature, there is an effect of preventing quantum dot deterioration that may occur in a high-temperature process.

1 is a view for explaining a method for producing a photo-conversion composite of the present invention.
2 is a view showing an embodiment of the light-conversion composite of the present invention.
3 is a view for explaining the quantum dot-polymer bead of the present invention.
4 is a cross-sectional view of the photo-conversion film of the present invention.
5 is an exploded perspective view showing an embodiment of the display device of the present invention.
6 is a cross-sectional view taken along line I-I 'of Fig. 5; Fig.
7 is an optical microscope photograph of the quantum dot-polymer bead prepared in Production Example 1. FIG.
8 is a photograph of the photoconversion film produced by Example 1, taken with a confocal microscope.
FIG. 9 is a photograph of a photoconversion film produced by a comparative example with a confocal microscope. FIG.
FIGS. 10 and 11 are graphs showing the scattering intensity according to the number of wafers of the light conversion films of Examples 1 to 4 measured by the incineration X-ray scattering method.
12 is a graph showing the luminous efficiency of the photoconversion film of Example 1 and the photoconversion film of the comparative example.
13 is a photograph showing the degree of edge deterioration of the photo-conversion film of Example 1 and the photo-conversion film of the comparative example.

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

The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

In the case where the word 'includes', 'having', 'done', etc. are used in this specification, other parts can be added unless '~ only' is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions.

In the case of a description of a temporal relationship, for example, if a temporal posterior relationship is described by 'after', 'after', 'after', 'before', etc., 'Is not used and is not contiguous.

The first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, the first component mentioned below may be the second component within the technical spirit of the present invention.

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, technically various interlocking and driving, and that the embodiments may be practiced independently of each other, It is possible.

The inventors of the present invention have conducted extensive research to develop a light-converting material capable of uniformly dispersing quantum dots in a low moisture-permeable and / or low-void matrix resin and minimizing deterioration of quantum dots. As a result, - polymer beads, the present invention has been accomplished.

A method of manufacturing a light-conversion composite according to the present invention includes the steps of: preparing a quantum dot-polymer bead; Mixing the quantum dot-polymer beads with a matrix resin to form a mixed solution; And curing the mixed solution, wherein the quantum dot-polymer bead is manufactured using a solvent volatilization method. When the quantum dot-polymer bead is prepared by using the solvent volatilization method as in the present invention, the quantum dot-polymer bead can be prepared at room temperature without a high temperature process, so that deterioration of quantum dots occurring in a high temperature process can be prevented.

FIG. 1 shows a method of manufacturing a photo-conversion composite according to the present invention. Hereinafter, each step will be described in more detail with reference to FIG.

First, a polymer and a first solvent are mixed to form a polymer dispersion (S1).

In this case, the polymer may be that the polymer with the surface of the affinity of the quantum dots preferably used, for example, the solubility parameter (SP, Solubility Parameter) is 19 Pa ^1/2 to 24MPa ^1/2 degree of the polymer. According to the studies of the present inventors, when a polymer having a solubility parameter within the above-described numerical range is used, the polymer coating layer is formed on the surface of the quantum dots by smoothly bonding the surface of the quantum dots with the polymer chain. On the other hand, the solubility parameter in the present invention is Polymer handbook;: Group A described in Chapter 7 (editors, J. Brandrup, EHImmergut, EAGrulke associate editors, A.Abe, DR Bloch 4 ^th ed New York.. John Wiley & Sons c1999) contribution methods, and the values shown in Table 2 of Chapter 7 of the above document were used as the contribution of each group used in the calculation.

More specifically, the polymer is preferably a polymer having a polar group in the main chain or side chain. When a polar group is included, the polar group is adsorbed on the surface of the quantum dots to easily form a polymer coating layer.

For example, the polymer may be a homopolymer or a copolymer including at least one selected from the group consisting of polyester, ethyl cellulose, polyvinyl pyridine, and combinations thereof in the main chain. Among them, polyester is particularly preferable in that the deterioration effect on quantum dots is small.

In addition, the polymer may have a polar group in its side chain. At this time, the polar group may include an oxygen component. For example, the polar group may be any one selected from the group consisting of -OH, -COOH, -COH, -CO, -O-, and combinations thereof.

In addition, the polymer may be a partially oxidized polymer. The partially oxidized polymer means a polymer in which an oxygen component is irregularly introduced into the main chain or side chain. For example, the partially oxidized polymer may be a partially oxidized polyester.

The polymer preferably has a number average molecular weight of about 300 g / mol to about 100,000 g / mol. When the number-average molecular weight of the polymer is less than 300 g / mol, the quantum dots are not sufficiently separated in the quantum dot-polymer beads, and the luminous efficiency may be lowered. When the number average molecular weight is more than 100,000 g / mol, This is because defects may occur.

On the other hand, the first solvent is for dissolving the polymer, preferably nonpolar solvent. The first solvent is preferably a high-volatile solvent having a low boiling point, for example, a boiling point of 85 ° C or less, preferably 50 ° C to 80 ° C or less, more preferably The temperature may be from 60 [deg.] C to 70 [deg.] C. More specifically, the first solvent is at least one selected from the group consisting of tetrahydrofuran (boiling point: 66 占 폚), chloroform (boiling point: 61 占 폚), cyclohexane (boiling point: 81 占 폚), hexane (boiling point: 68.5 to 69.1 占 폚) ), And among them, chloroform is particularly preferable.

On the other hand, the polymer content in the polymer dispersion is preferably about 15 to 35% by weight of the polymer dispersion. If the content of the polymer is less than 15% by weight, the volatilization amount of the solvent increases, and pores may be formed excessively in the quantum dot-bead. If the content of the polymer is more than 35% by weight, the viscosity may increase and the film formability may deteriorate. In consideration of film formability, the polymer dispersion preferably has a viscosity of about 500 cP to 1000 cP.

Next, the quantum dot and the second solvent are mixed to form a quantum dot dispersion (S2). At this time, the formation time point of the quantum dot dispersion is not particularly limited, and may be performed, for example, at the same time as the polymer dispersion forming step, or before or after the polymer dispersion forming step.

The quantum dot is a semiconductor crystal having a size of several nanometers (nm) having a quantum confinement effect as a light emitting nanoparticle, and converts the wavelength of light injected from the light source and emits the light.

The quantum dots may be doped with a metal such as CdS, CdO, CdSe, CdTe, Cd ₃ P ₂ , Cd ₃ As ₂ , ZnS, ZnO, ZnSe, ZnTe, MnS, MnO, MnSe, MnTe, MgO, MgS, CaO, CaS, CaSe, CaTe, SrO, SrS, SrSe, SrTe, BaO, BaS, BaSe, BaTE, HgO, HgS, HgSe, HgTe, Hg1 2, AgI, AgBr, Al 2 O 3, Al 2 S 3, Al _{2 Se 3, Al 2 Te 3} , Ga 2 O 3, Ga 2 S 3, Ga 2 Se 3, Ga 2 Te 3, In 2 O 3, In 2 S 3, In 2 Se 3, In 2 Te 3, SiO _{2, GeO 2, SnO 2,} SnS, SnSe, SnTe, PbO, PbO 2, PbS, PbSe, PbTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, GaInP 2, InN, InP, InAs, A single layer or a multilayer structure including at least one semiconductor crystal selected from the group consisting of InSb, In ₂ S ₃ , In ₂ Se ₃ , TiO ₂ , BP, Si, Ge, have.

On the other hand, the diameter of the quantum dot may be about 1 nm to 10 nm. Since the emission wavelength varies depending on the size of the quantum dot, a desired color light can be obtained by selecting a quantum dot having an appropriate size. In the present invention, the quantum dots may include, for example, at least one selected from the group consisting of red light emitting quantum dots converting incident light into red light and green light emitting quantum dots converting incident light into green light.

On the other hand, the quantum dots may include a capping layer on the surface of the quantum dots to prevent aggregation between the quantum dots. The capping layer may be a ligand layer coordinately bonded to the surface of the quantum dot, or may be a surface layer coated with hydrophobic organic molecules.

For example, the capping layer may be a layer of material selected from the group consisting of phosphine oxides having long-chain alkyl or aryl groups that exhibit apolarity, organic amines, organic acids, phosphonic acids, and combinations thereof. For example, the capping layer can comprise at least one of tri-n-octylphosphine oxide (TOPO), stearic acid, palmitic acid, octadecylamine, hexadecylamine, dodecylamine, lauric acid, And combinations thereof.

On the other hand, the second solvent is for dissolving the quantum dots for mixing with the polymer dispersion or for replacing the solvent of the commercially available quantum dots solution, preferably nonpolar solvent. In general, commercially available quantum dots are commercially available in the form of a solution dissolved in a solvent such as toluene. In the present invention, miscibility with the polymer dispersion is improved by replacing the solvent of the commercially available quantum dot solution with a second solvent. For this, the second solvent is preferably a solvent compatible with the first solvent. The second solvent is preferably a high-volatile solvent having a low boiling point. For example, the second solvent may have a boiling point of 85 占 폚 or lower, preferably 50 占 폚 to 80 占 폚 or lower, More preferably 60 ° C to 70 ° C. More specifically, the second solvent is at least one selected from the group consisting of tetrahydrofuran (boiling point: 66 占 폚), chloroform (boiling point: 61 占 폚), cyclohexane (boiling point: 81 占 폚), hexane (boiling point: 68.5 to 69.1 占 폚) ), And among them, chloroform is particularly preferable.

The first solvent and the second solvent may be the same or different from each other, but from the viewpoint of process convenience and compatibility, the same is more preferable.

After the polymer dispersion and the quantum dot dispersion are formed through the above process, the two solutions are mixed to form a quantum dot-polymer mixed solution (S3).

In the present invention, since a polymer having affinity with the surface of a quantum dot is used, when a polymer dispersion and a quantum dot dispersion are mixed, a part of the polymer chain bonds to the surface of the quantum dot to form a brush layer. That is, the polymer surrounds the surface of the quantum dot to form a polymer coating layer. The quantum dots are spaced apart from each other by the polymer coating layer, and as a result, the degradation of the luminous efficiency caused by the aggregation of the quantum dots can be minimized.

Next, the dispersant and the third solvent are mixed to form a dispersant solution (S4).

At this time, the point of time when the dispersant solution is formed is not particularly limited, and may be performed, for example, simultaneously with the step of forming the quantum dot-polymer mixed solution, or may be performed before or after the step of forming the quantum dot-

The dispersant solution is used for forming droplets containing quantum dots and polymers through phase separation in a process to be described later. As the third solvent, it is preferable to use a polar solvent capable of phase separation with the first solvent and the second solvent. For example, water may be used as the third solvent.

The dispersant is for maintaining the phase separation between the droplet and the third solvent, and may be an amphiphilic organic monomolecular or amphiphilic polymer. The dispersant may be an ionic dispersant or a nonionic dispersant. Preferably, the dispersing agent may be polyvinyl alcohol.

The content of the dispersant in the dispersant solution may be about 0.1 wt% to 5 wt%, preferably about 0.5 wt% to 1 wt%. If the content of the dispersing agent is less than 0.1 wt%, it may be difficult to form and maintain the droplets. If the content of the dispersing agent is more than 5 wt%, the droplet size may be decreased and the luminous efficiency may be deteriorated.

Next, the quantum dot-polymer mixed solution and the dispersant solution are mixed to form a droplet containing the quantum dot and the polymer (S5).

As described above, since the quantum dot-polymer mixed solution contains a non-polar solvent and the dispersant solution contains a polar solvent, the quantum dot-polymer mixed solution and the dispersant solution do not mix with each other but a phase separation occurs and a droplet is formed. At this time, a quantum dot, a polymer, a solvent of a quantum dot-polymer mixture liquid (that is, a nonpolar solvent) is present inside the droplet, and a polar solvent which is a solvent of the dispersant solution exists outside the droplet. For smooth droplet formation, the quantum dot-polymer mixed solution and the dispersant solution may be mixed using a homogenizer or the like.

On the other hand, the dispersant is bonded to the surface of the droplet to prevent agglomeration of the droplet, and the shape of the droplet can be maintained. More specifically, one side of the dispersing agent is located on the surface side of the droplet, which is a non-polar solvent, and the other side is disposed on the side of the polar solvent, so that the dispersing agent surrounds the droplet so that the shape of the droplet can be maintained. On the other hand, the size of the droplet can be controlled according to the concentration of the dispersant. For example, as the concentration of the dispersant increases, the size of the droplet becomes smaller.

When a droplet is formed through the above process, the solvent existing in the droplet is volatilized (S6).

The step of volatilizing the solvent present inside the droplet may be performed by a method of reducing the pressure of the solution in which the droplet is formed at room temperature. More specifically, nitrogen may be purged from one side of the solution and the solvent of the droplet may be volatilized by drawing a vacuum from the other side by a pump. Since the solvent of the quantum dot-polymer mixed solution existing in the droplet is a nonvolatile, high-volatility solvent with low boiling point, it can be easily volatilized even by decompressing at room temperature without any additional heating step.

On the other hand, the solvent volatilization can be performed while stirring with a magnetic stirrer to prevent the droplets from being re-agglomerated, and can be performed, for example, with stirring at about 100 rpm.

On the other hand, the solvent volatilization time can be appropriately controlled depending on the kind of solvent present in the droplet. For example, when chloroform is used as the first solvent and the second solvent, the volatilization time may be about one hour.

When the solvent in the droplet is volatilized through the above process, the quantum dot-polymer beads including the quantum dot and the polymer are formed. On the other hand, when the beads are formed through the solvent volatilization method as in the present invention, pores may be formed in vacancies where the solvent is volatilized in the quantum dot-polymer beads.

Next, the quantum dot-polymer beads are collected (S7).

The collection of the quantum dot-polymer beads may be performed by collecting, washing and drying the quantum dot-beads.

First, the QD-polymer beads are collected on the filter by filtering using a filtering device. The quantum dot-polymer beads on the filter are then washed several times with methanol and water. When the QD-polymer beads are dried immediately after being collected, they become hard powder, and there is a problem that re-dispersion is not performed well. However, when the collected quantum dot-polymer beads are washed with methanol, it is possible to form a powder that is well dispersed when it is dispersed in a solvent after drying.

The quantum dot-polymer beads are then obtained by drying in a vacuum chamber to remove residual moisture and methanol.

The quantum dot-polymer bead manufacturing steps (S1 to S8) can be performed at room temperature, and no steps such as heating or cooling are required. Therefore, deterioration of quantum dots, which may be caused by temperature changes, can be minimized.

Meanwhile, the quantum dot-polymer beads prepared through the above process may have an average particle diameter of about 5 to 200 μm, and the concentration of the quantum dots 301 in the quantum dot-polymer beads may be, for example, 0.1% 1% by weight.

When the quantum dot-polymer beads are obtained through the above-described method, the mixture is mixed with the matrix resin to prepare a mixed solution of the quantum dot-polymer beads and the matrix resin (S8).

At this time, it is preferable that the matrix resin is a resin having low moisture permeability and low pouring property. For example, the matrix resin may include epoxy, epoxy acrylate, polychlorotrifluoroethylene, polyethylene, polypropylene, polyvinyl alcohol, or combinations thereof.

The epoxy resin may be a resin having an epoxy group, for example, a bisphenol A resin, a bisphenol F resin, or the like, and these epoxy resins have a low water permeability and a low water permeability due to the characteristics of the main chain.

The epoxy acrylate resin is a resin in which an epoxide group of an epoxy resin is substituted with an acrylic group. For example, the epoxy acrylate resin may be bisphenol A glycerolate diacrylate, Bisphenol A ethoxylate dimethacrylate, bisphenol A glycerol dimethacrylate, bisphenol A ethoxylate dimethacrylate, and the like. And a combination thereof. Epoxy acrylate resins, like epoxy resins, have low moisture permeability and durability due to their main chain properties.

The polychlorotrifluoroethylene has a low water and oxygen permeability, polyethylene and polypropylene have low water permeability, and polyvinyl alcohol has low oxygen permeability.

On the other hand, the matrix resin can be provided in a fluid solution state in which the resin is dissolved in a solvent in consideration of compatibility with the quantum dot-polymer beads, and further includes a photoinitiator for photocuring at the time of forming the photo- .

On the other hand, a light-converting composite material can be obtained by curing the mixture of the quantum dot-polymer beads and the matrix resin (S9). At this time, the curing may be performed by a photo-curing method, for example, a method of applying the mixed solution to a substrate or the like, and then irradiating an active energy ray such as ultraviolet rays.

Next, the photo-conversion composite of the present invention produced by the above-described method will be described.

Figure 2 shows a light-conversion composite of the present invention. 2, the light-conversion composite of the present invention comprises a matrix resin 400 and quantum dot-polymer beads 300 dispersed in the matrix resin 400, wherein the light-conversion composite comprises an incineration X The wave number q at the peak point of the scattering intensity graph according to the wave number measured by the Small Angle X-ray Scattering method is in the range of 0.0056 Å ^-1 to 0.045 Å ^{- 1} is the degree, preferably, 0.01Å ^-1 to 0.040Å ^{- 1} degree, and more preferably be on the order of ^-1 to ^-1 0.020Å 0.030Å.

At this time, the Small Angle X-ray Scattering method uses X-ray diffraction information in a very small scattering angle range, for example, a scattering angle within 3 degrees, It is a technique to grasp the nanostructure, and the structure of the material is grasped by using the scattering intensity distribution of X-ray. More specifically, the structure measurement of the substance by the incineration X-ray scattering method can be performed by, for example, projecting a transmission and incineration X-ray scattering beam of a Pohang radiation accelerator onto a measurement target material, (Intensity) graph, and then calculating the interval or distribution between the materials. The inventors of the present invention cured the light-converting composite material prepared according to the method of the present invention in order to examine the structure of the light-conversion composite material of the present invention, and then transmitted the transmitted and incinerated X-ray scattering beam of the Pohang radiation accelerator. As a result, the optical composite material of the present invention was found to have a wave number q at a peak point on a scattering intensity graph according to a wave number of about 0.0056 Å ^-1 to about 0.045 Å ^-1 . On the other hand, the wave number q is a value related to the surface interval of the quantum dots, and the interval of the quantum dots can be calculated from the wave number q through the following equation (1).

Equation 1: q = 4? Sin? /? = 2? / D

In the above formula (1), q is a wave number,? Is a scattering angle,? Is an x-ray wavelength, and d is a surface interval.

The distance between the quantum dots in the light-conversion composite of the present invention is approximately 14 nm to 112 nm. Considering that the diameter of a commonly used quantum dot is 2 to 8 nm and the length of a ligand attached to the surface of the quantum dot is about 1 to 2 nm, when the quantum dots are aggregated, the distance between the quantum dots is about 4 to 12 nm. That is, the wave number q at the peak point on the wave number vs. scatter intensity graph measured by the Small Angle X-ray Scattering method is 0.0056 Å ^-1 to 0.045 Å ^-1 means that the quantum dots do not aggregate in the light-converting composite material of the present invention and are well dispersed.

The reason why the quantum dots can be evenly dispersed in the light-conversion composite of the present invention is that the quantum dot-polymer beads used in the present invention are not simply composed of a mixture of quantum dots and polymers, but a polymer is coated on the surface of a single quantum dots, It is considered that this is due to the fact that a large number of these monomer units are aggregated to form cluster type quantum dot-polymer beads.

Fig. 3 is a view for explaining the quantum dot-polymer bead of the present invention. 3, the quantum dot-polymeric beads 300 of the present invention are formed by aggregating a plurality of quantum dot-polymer unit bodies 310, and the quantum dot-polymer unit 310 includes quantum dots 311, A portion of the polymer 312 is combined with the surface of the quantum dot to form a coating layer.

At this time, specific characteristics and components of the quantum dot 311 and the polymer 312 are the same as described above.

That is, the quantum dot 311 may include at least one selected from the group consisting of, for example, a red light emitting quantum dot for converting incident light into red light and a green light emitting quantum dot for converting incident light into green light. More specifically, , for example, CdS, CdO, CdSe, CdTe, Cd ₃ P _2, Cd ₃ as _2, ZnS, ZnO, ZnSe, ZnTe, MnS, MnO, MnSe, MnTe, MgO, MgS, MgSe, MgTe, CaO, CaS , CaSe, CaTe, SrO, SrS , SrSe, SrTe, BaO, BaS, BaSe, BaTE, HgO, HgS, HgSe, HgTe, Hg1 2, AgI, AgBr, Al 2 O 3, Al 2 S 3, Al 2 Se 3 _{, Al 2 Te 3, Ga 2} O 3, Ga 2 S 3, Ga 2 Se 3, Ga 2 Te 3, In 2 O 3, In 2 S 3, In 2 Se 3, In 2 Te 3, SiO 2, GeO ₂ , SnO ₂ , SnS, SnSe, SnTe, PbO, PbO ₂ , PbS, PbSe, PbTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, GaInP _{2 ,} InN, InP, InAs, InSb, In _{2 s 3, in 2 Se 3} , a single-layer or multi-containing _{TiO 2, BP, Si, Ge} , and the semiconductor crystal at least one selected from the group consisting of a combination of Layer structure.

Also, the polymer 312 may be a polymer having a solubility parameter of 19 MPa ^1/2 to 24 MPa ^1/2 , and preferably a polymer having a polar group in the main chain or side chain. For example, the polymer may be a homopolymer or copolymer containing at least one member selected from the group consisting of polyester, ethyl cellulose, polyvinyl pyridine and a combination thereof in the main chain, or may be a homopolymer or a copolymer containing -OH, -COOH, -OH, -COH, -CO, -O-, and a combination thereof. Alternatively, the polymer may be a partially oxidized polymer such as partially oxidized polyester. The polymer preferably has a number average molecular weight of about 300 g / mol to about 100,000 g / mol.

The specific characteristics and components of the matrix resin 400 are the same as those described above. That is, the matrix resin is preferably a resin having low moisture permeability and low pouring property. For example, the matrix resin may be an epoxy, an epoxy acrylate, a polychlorotrifluoroethylene, a polyethylene, a polypropylene, a polyvinyl alcohol And combinations of these.

Meanwhile, the optical composite material of the present invention may further include a dispersant 320. The dispersant 320 is attached to the surface of the quantum dot-polymer bead 300 with the dispersant contained in the dispersant solution described in the above-described production method, so that the quantum dot-polymer bead 300 is dispersed evenly in the matrix resin 400 And to be able to help. The dispersant 320 may be an amphiphilic organic monomolecular or amphiphilic polymer, and preferably the dispersant may be polyvinyl alcohol.

In addition, the optical composite material of the present invention may further include a photoinitiator for photo-curing.

Next, the photo-conversion film of the present invention will be described. 4 shows an embodiment of the photo-conversion film of the present invention. 4, the photo-conversion film 270 of the present invention includes a first barrier film 271, a photo-conversion layer 272, and a second barrier film 273. At this time, the light conversion layer 272 is a layer for converting the wavelength of light generated from the light source, and is formed of the light conversion composite material of the present invention.

More specifically, the photo-conversion film of the present invention can be produced by coating a mixture of the above-described quantum dot-polymer beads and a matrix resin between the first barrier film 271 and the second barrier film 273, have. More specifically, a method of coating a mixture of the quantum dot-polymer beads and the matrix resin on the first barrier film 271 and then curing the second barrier film 273 or a method of curing the second barrier film 273 A method in which a mixture of the quantum dot-polymer beads and the matrix resin is coated on the first barrier film 271 and then the first barrier film 271 is cemented and cured. On the other hand, the curing may be performed through a photo-curing method. Concrete contents related to the other light-converting composite material have already been described above, and therefore, a detailed description thereof will be omitted.

The first barrier film 271 and the second barrier film 273 are for supporting and protecting the light conversion layer 272. More specifically, So as to prevent the quantum dots from being deteriorated by being introduced into the conversion layer 272.

For this, the first barrier film 271 and the second barrier film 273 may include a single material or a composite material having high water and / or oxygen barrier properties. For example, the first barrier film 271 and the second barrier film 273 may be a polymer having high water and / or oxygen barrier properties, for example, polyethylene, polypropylene, polyvinyl chloride, polyvinyl alcohol , Ethylene vinyl alcohol, polychlorotrifluoroethylene, polyvinylidene chloride, nylon, polyamino ether, cycloolefin homopolymers or copolymers.

On the other hand, the first barrier film 271 and the second barrier film 273 are shown as a single layer, but the present invention is not limited thereto. The first barrier film 271 and the second barrier film 273 may be formed of multiple layers. For example, the first barrier substrate 271 and the second barrier substrate 273 may have a structure in which a protective film is laminated on the base substrate. For example, the first barrier film 271 and the second barrier film 273 may be in the form of an inorganic film or an organic-inorganic hybrid film coated on the base substrate with high water and / or oxygen barrier properties At this time, the inorganic film or the organic-inorganic hybrid film may be composed mainly of an oxide or nitride such as Si, Al, or the like. In this case, a polymer film having high light transmittance and heat resistance can be used as the base substrate. For example, a polyethylene terephthalate (PET), a polyethylene naphthalate (PEN), a cyclic olefin copolymer (COC) A polymer film including an olefin polymer (COP) or the like may be used.

The first barrier film 271 and the second barrier film 273 are formed under conditions of a relative humidity of 10 ^-1 g / m ² / day to 10 ^-5 g / m ² / day and, under 23 ℃, 0% relative humidity, it is preferable that the air permeability rate of about ^{10 -1 cc / m 2 / day} / atm to about ^{10 -2 cc / m 2 / day} / atm.

The linear transmittance of the first barrier film 271 and the second barrier film 273 is preferably about 88% to 95% in the range of 420 nm to 680 nm in the visible light region.

As described above, the light conversion film 270 having the light conversion layer 272 formed of the light conversion composite material of the present invention has a wave number measured by Small Angle X-ray Scattering method, the scattering intensity (intensity) is a quantum dot frequency of a peak point (wave number) of the graph 0.0056Å q ^-1 to 0.045Å according ^{to 1,} and preferably about, 0.01Å ^-1 to ^0.040Å-1 is the degree, more preferably 0.020Å 0.030Å about ^-1 to ^-1, and is evenly dispersed to the quantum dot in the light conversion layer 272. As a result, the light conversion film of the present invention is excellent in light emission efficiency because it absorbs less light.

Further, in the light conversion film 270 of the present invention, since the light conversion layer 272 is made of matrix resin having low moisture permeability and / or low light permeability, edge deterioration is remarkably small even in a high temperature and high humidity environment. Concretely, the photovoltaic film of the present invention has a damage length of 2 mm or less, preferably 1 mm or less, measured after standing for 10 days at 60 ° C and 90% relative humidity.

Next, the backlight unit and the display device of the present invention will be described.

5 and 6 show an embodiment of the display device of the present invention.

As shown in Figs. 5 and 6, the display apparatus of the present invention includes a backlight unit 200 and a display panel 100. Fig.

The backlight unit 200 is for providing light to the display panel 100 and includes a light source unit 240 including a plurality of light sources 240b and the light conversion film 270 of the present invention . The backlight unit 200 may further include a bottom case 210, a reflection plate 220, a light guide plate 230, a guide panel 250, and an optical sheet 260 as required. Since details of the light conversion film 270 have been described above, other components of the backlight unit will be described.

First, the light source unit 240 provides light to the display panel 100 and may be disposed inside the bottom case 210.

The light source unit 240 includes a plurality of light sources 240b and a printed circuit board 240a on which the plurality of light sources 240b are mounted.

In this case, the light source 240b may be a blue light source that generates blue light. For example, the light source 240b may be a blue light emitting diode. In this case, the light conversion film 270 may include a light conversion layer formed by a light conversion composite material including a red light emission quantum dot that converts incident light into red light and a green light emission quantum dot that converts incident light into green light.

Alternatively, the light source 240b may be a combination of a blue light source for generating blue light and a green light source for generating green light. For example, the light source 240b may be a combination of a blue light emitting diode and a green light emitting diode. At this time, the light conversion film 270 may include a light conversion layer formed by a light conversion composite material including red light emitting quantum dots that convert incident light into red light. In this case, since it is not necessary to use the green light emitting quantum dots that occupy many of the quantum dots used in the photoconversion film, the amount of the quantum dots can be drastically reduced, resulting in a reduction in the manufacturing cost of the light converting film, There is an advantage in that the thickness of the conversion film is reduced, which is advantageous for thinning.

Meanwhile, the printed circuit board 240a is electrically connected to the light source 240b. The light source 240b may be driven by receiving a driving signal through the printed circuit board 240a.

The printed circuit board 240a has a mounting surface on which the light source 240b is mounted and an adhesive surface facing the mounting surface. The bonding surface of the printed circuit board 240a is attached to the bottom case 210. The printed circuit board 240a may be disposed on one side of the bottom case 210 in a bar shape.

Although the printed circuit board 240a is attached to the inner side surface of the bottom case 210, the present invention is not limited thereto. The printed circuit board 240a may be attached to the inner upper surface of the bottom case 210 or may be attached to the lower surface of the bending extension 211 of the bottom case 210. [

Although the light source unit 240 is disposed on one side of the bottom case 210 in the drawing, the light source unit 240 may be disposed on both sides of the bottom case 210 facing each other . Although the edge-type backlight unit 200 is shown in the drawing, the backlight unit 200 may be a direct-type backlight unit 200. That is, the light source unit 240 may be disposed on the inner upper surface of the bottom case 210.

Meanwhile, the bottom case 210 has a top opened shape. The bottom case 210 has side walls extending in the form of a closed curve to accommodate the light source unit 240, the light guide plate 230, the reflection plate 220, the optical sheet 260, and the light conversion film 270 . At this time, at least one side wall of the bottom case 210 may include a bending extension 211 extending from the upper edge to cover the light source unit 240. That is, one end surface of the bottom case 210 may have a shape of 'C'. At this time, a reflection member 243 may be disposed on the lower surface of the bending extension 211.

The reflective member 243 may be a light source housing, a reflective film, or a reflective tape. The reflective member 243 can prevent the light from the light source unit 240 from being directly emitted to the display panel 100. In addition, the reflective member 243 may increase the amount of light incident into the light guide plate 230. Thus, the reflective member 243 can improve the light efficiency, brightness, and image quality of the display device.

Meanwhile, the bending extension 211 may be omitted in the bottom case 210. That is, one end surface of the bottom case 210 may have a shape of 'B'. The bottom case 210 is fastened to the guide panel 250.

The guide panel 250 includes inward projections. The display panel 100 may be seated and supported on the protrusion of the guide panel 250. The guide panel 250 may also be referred to as a support main or a mold frame.

The guide panel 250 is disposed to surround the edge of the backlight unit 200 so as to be adhered to the display panel 100. That is, the guide panel 250 has a frame shape. For example, the guide panel 250 may have a rectangular frame shape. The guide panel 250 may have an opening in a region corresponding to the bending extension 211 of the bottom case 210.

Although not shown in the drawing, the bottom case 210 and the guide panel 250 may be assembled with hooks or assembled together with projections and recesses, respectively. Further, the bottom case 210 and the guide panel 250 may be bonded together through an adhesive member.

However, the present invention is not limited thereto, and the guide panel 250 may be disposed on the light source unit 240. At this time, a reflective member 243 may be disposed on the lower surface of the guide panel 250 corresponding to the light source unit 240.

Next, the light guide plate 230 uniformly guides the light provided from the light source unit 240 to the liquid crystal display panel 100 through total reflection, refraction, and scattering. Here, the light guide plate 230 is accommodated in the bottom case 210.

Although the light guide plate 230 is formed to have a certain thickness in the drawing, the shape of the light guide plate 230 is not limited thereto. For example, the thickness of the light guide plate 230 may be thinner than both sides of the light guide plate 230 in order to reduce the overall thickness of the backlight unit 200, You may.

In addition, one surface of the light guide plate 230 may include a pattern of a specific shape to supply a uniform surface light source. For example, the light guide plate 230 may include various patterns such as an elliptical pattern, a polygon pattern, and a hologram pattern to guide light incident thereupon .

In the drawing, the light source unit 240 is disposed on a side surface of the light guide plate 230, but is not limited thereto. The light source unit 240 may be disposed to correspond to at least one surface of the light guide plate 230. For example, the light source unit 240 may be disposed to correspond to one side or both sides of the light guide plate 230, and the light source unit 240 may be disposed to correspond to a lower surface of the light guide plate 230 have.

The reflection plate 220 is disposed on the path of light emitted from the light source unit 240. In detail, the reflection plate 220 is disposed between the light guide plate 230 and the bottom case 210. That is, the reflection plate 220 is disposed below the light guide plate 230. The reflection plate 220 may reflect light traveling toward the upper surface of the bottom case 210 to the light guide plate 230 to increase light efficiency.

The reflection plate 220 may be disposed on the light source unit 240 when the light source unit 240 is disposed to correspond to a lower surface of the light guide plate 230. [ In detail, the reflection plate 220 is disposed on the printed circuit board 240a of the light source unit 240. [ In addition, the optical member 220 may include a plurality of holes for coupling the plurality of light sources 240b.

That is, the plurality of light sources 240b are inserted into a plurality of holes of the reflection plate 220, and the light source 240b may be exposed to the outside through the holes. Accordingly, the reflection plate 220 may be disposed on the printed circuit board 240a on the side of the light source 240b.

An optical sheet 260 for diffusing and condensing light is disposed on the light guide plate 230. For example, the optical sheet 260 may include a diffusion sheet 261, a first prism sheet 262, and a second prism sheet 263.

The diffusion sheet 261 is disposed on the light guide plate 230. The diffusion sheet 261 improves the uniformity of the transmitted light. The diffusion sheet 261 may include a plurality of beads.

The first prism sheet 262 is disposed on the diffusion sheet 261. The second prism sheet 263 is disposed on the first prism sheet 262. The first prism sheet 262 and the second prism sheet 263 increase the straightness of light passing therethrough. Therefore, the light emitted onto the light guide plate 230 can be processed into a surface light source of higher brightness by transmitting the light through the optical sheet 260.

A light conversion film 270 may be disposed between the optical sheet 260 and the light guide plate 230.

Next, the display panel 100 is for realizing a screen, and may be, for example, a liquid crystal display panel (LCD). For example, the display panel 100 includes a first substrate 110 and a second substrate 120 which are bonded together with a liquid crystal layer (not shown) therebetween.

Further, although not shown in the figure, a polarizer (not shown) may be further disposed on the outer surfaces of the first substrate 110 and the second substrate 120 to selectively transmit only specific polarized light. That is, a polarizing plate may be disposed on the upper surface of the first substrate 110 and the rear surface of the second substrate 120.

Although not specifically shown in the figure, the display panel is divided into a display area and a non-display area. In the display area, a gate wiring and a data wiring are disposed on one surface of the first substrate 110. The gate wirings and the data wirings intersect each other with a gate insulating film interposed therebetween to define a pixel region.

The first substrate 110 may be a thin film transistor substrate. A thin film transistor (TFT) is disposed on one surface of the first substrate 110 in a crossing region between the gate line and the data line. That is, a thin film transistor is provided in the pixel region. In addition, a pixel electrode is disposed in each pixel region on one surface of the first substrate 110. The thin film transistor and the pixel electrode are electrically connected.

The thin film transistor includes a gate electrode, a semiconductor layer, a source electrode, and a drain electrode. The gate electrode may be formed by branching from the gate wiring. Further, the source electrode may be formed by branching from the data line. The pixel electrode may be electrically connected to a drain electrode of the thin film transistor.

The thin film transistor may have a bottom gate structure, a top gate structure, a double gate structure, or the like. That is, the structure and the like of the thin film transistor can be variously changed and modified within the range not deviating from the technical idea of the embodiment.

The second substrate 120 may be a color filter substrate. A black matrix having a lattice shape covering a pixel region is disposed on one surface of the second substrate 120 of the display panel 100 to cover a non-display region such as a thin film transistor formed on the first substrate 110. In addition, a red color filter layer, a green color filter layer, and a blue color filter layer, which are sequentially and repeatedly arranged in correspondence to the respective pixel regions within these lattices, may be included.

In addition, the display panel 100 includes a common electrode that forms an electric field with the pixel electrode to drive the liquid crystal layer. The twisted nematic (TN) mode, the VA (Vertical Alignment) mode, the IPS (In Plane Switching) mode, or the FFS (Fringe Field Switching) mode can be used to control the alignment of the liquid crystal molecules. The common electrode may be disposed on the first substrate 110 or the second substrate 120 according to a method of controlling the alignment of the liquid crystal molecules.

The display panel 100 may be a display panel 100 having a color filter on transistor (COT) structure in which a thin film transistor, a color filter layer, and a black matrix are formed on the first substrate 110. The second substrate 120 is bonded to the first substrate 110 with a liquid crystal layer interposed therebetween.

That is, a thin film transistor is disposed on the first substrate 110, and a color filter layer may be disposed on the thin film transistor. At this time, a protective layer may be formed between the thin film transistor and the color filter layer.

In addition, the first substrate 110 is provided with pixel electrodes which are in contact with the thin film transistors. At this time, in order to improve the aperture ratio and simplify the mask process, the black matrix may be omitted, and the common electrode may be formed to serve also as the black matrix.

Although not shown in the drawing, the display panel 100 is connected to a driving circuit (not shown) for supplying a driving signal from the outside. The driving circuit unit may be mounted on the substrate of the display panel 100 or may be connected to the display panel 100 through a connecting member such as a tape carrier package.

Although the backlight unit and the display panel have been described above with reference to the drawings, the configurations of the backlight unit and the display panel applied to the present invention are not limited to the configurations described in the drawings. That is, the backlight unit and the display device of the present invention may omit some of the above-described configurations, or may have a modified configuration, and may further include components not described above.

Next, the present invention will be described in more detail with reference to concrete examples.

Manufacturing example  One: Qdot - Polymers Bead  (I)

A partially oxidized polyester having a number average molecular weight of 28,000 g / mol and a solubility parameter value of 22 MPa ^1/2 was dissolved in chloroform to prepare a polymer dispersion. The polyester of the polymer dispersion was 25 wt%. A quantum dot dispersion (70 mg / mL) was prepared by replacing the solvent of the ZnCdSe / ZnS quantum dot solution dissolved in the toluene solvent with chloroform. The quantum dot dispersion was added to the polymer dispersion and stirred to form a quantum dot-polymer mixed solution. At this time, the polymer dispersion and the quantum dot dispersion were mixed such that the content of the quantum dots in the quantum dot-polymer mixture solution was 0.5 wt%.

Polyvinyl alcohol was dissolved in water to form a 1 wt% dispersant aqueous solution. Then, 10 g of the dispersant aqueous solution and 2 g of the quantum dot-polymer mixed solution were mixed in a three neck flask. Thereafter, the droplets were homogenized by a homogenizer at 10000 rpm for 1 minute.

A magnetic steering bar was placed in the flask and stirred with a magnetic stirrer. One of the holes of the three-way flask was closed, the nitrogen was purged from the other inlet, and the vacuum was pulled out from the other inlet at the same time, and the solvent of the droplet was volatilized for 1 hour.

The solution in the volatilized volatile flask was filtered using the filtering equipment and the QD - polymer beads were collected on the filter. The quantum dot-beads on the filter were then washed several times with methanol and water. Then, the remaining moisture and methanol were removed by storing and drying in a vacuum chamber for one day, and quantum dot-polymer beads (I) were collected. The previous step was conducted at room temperature.

FIG. 7 shows an optical microscope photograph of the quantum dot-polymer bead (I) prepared by the above method. Referring to FIG. 7, it can be seen that quantum dot-polymer beads are formed.

Manufacturing example  2: Qdot - Polymers Bead  (II)

(Sigma Aldrich) having a solubility parameter of 21.1 MPa < ^1/2 > was used instead of the polyester, and the polymer dispersion and the quantum dot dispersion were mixed such that the content of the quantum dots in the quantum dot- The quantum dot-polymer bead (II) was prepared in the same manner as in Production Example 1.

Manufacturing example  3: Qdot - Polymers Bead  (III)

The quantum dot-polymer bead (III) was prepared in the same manner as in Production Example 2, except that the polymer dispersion and the quantum dot dispersion were mixed so that the content of the quantum dots in the quantum dot-polymer mixture solution was 3 wt%.

Manufacturing example  4 : Qdot - Polymers Bead  (IV)

The quantum dot-polymer bead (IV) was prepared in the same manner as in Production Example 2, except that the polymer dispersion and the quantum dot dispersion were mixed such that the content of the quantum dots in the quantum dot-polymer mixture solution was 5 wt%.

Manufacturing example  5: Matrix resin

Bisphenol-A glycerolate diacrylate was mixed with trimethylolpropane triacrylate (TMPTA) in a ratio of 4: 1, Irgacure 184 was added in an amount of 5 wt%, and the mixture was stirred to form an epoxy acrylate resin.

Manufacturing example  6: Mixed resin for photo-conversion composite material A

3 wt% of the quantum dot-polymer beads (I) obtained in Production Example 1 was added to 97 wt% of the epoxy acrylate resin prepared in Preparation Example 5 and stirred to prepare a mixed resin A for a light conversion composite.

Manufacturing example  7: Mix for photoconversion composite material Resin B

Except that the quantum dot polymeric beads (II) obtained in Production Example 2 were used in place of the quantum dot-polymeric beads (I) B was prepared.

Manufacturing example  8: Mixed resin for photo-conversion composite material C

Except that the quantum dot polymeric beads (III) obtained in Production Example 3 were used in place of the quantum dot-polymeric beads (I) C.

Manufacturing example  9: Mixed resin for photo-conversion composite material D

A mixed resin D for a photoconversion composite material was prepared in the same manner as in Production Example 6, except that the quantum dot polymeric bead (IV) obtained in Production Example 4 was used instead of the quantum dot-polymeric bead (I).

Example  One

The mixed resin for the light-converting composite material prepared in Production Example 6 A was coated between a first barrier film (i-component, 50 占 퐉) and a second barrier film (i-component, 50 占 퐉), and then exposed to UV light to prepare a light conversion film. Fig. 8 shows an optical microscope photograph of the photo-conversion film of Example 1. Fig. 8, it is confirmed that the quantum dot-polymer beads are dispersed in the film.

Example  2

Mixed resin for photoconversion composite material A photoconversion film was prepared in the same manner as in Example 1, except that the mixed resin B for the photoconversion composite material prepared in Preparation Example 7 was used instead of the mixed resin B for the photoconversion composite material.

Example  3

Instead of the mixed resin A for the light-converting composite material, the mixed resin for the light-converting composite material prepared in Production Example 8 C was used as a light-absorbing film.

Example  4

Mixed resin for photoconversion composite material A photoconversion film was prepared in the same manner as in Example 1 except that the mixed resin D for the photoconversion composite material prepared in Production Example 9 was used instead of the mixed resin D for the photoconversion composite material.

Comparative Example

ZnCdSe / ZnS quantum dots were dissolved in a lauryl acrylate monomer to form a quantum dot-monomer solution.

Trimethylolpropane triacrylate and Irgacure 184 were mixed and stirred to form an acrylic resin. Thereafter, the quantum dot-monomer solution was added to the acrylic resin and stirred, and then coated between the first barrier film (i-component, 50 m) and the second barrier film (i-component, 50 m). Subsequently, the photoconversion film was prepared by curing by exposure to UV.

Fig. 9 shows an optical microscope photograph of the light conversion film produced by the comparative example. 9, it can be confirmed that the quantum dots do not form beads and are distributed throughout the light conversion layer in the optical film of the comparative example.

Experimental Example  1: Incineration X-ray scattering measurement

The scattering intensity intensities according to the wave numbers q of the photoconversion films prepared in Examples 1 to 4 were measured using the transmission and incineration X-ray scattering beamlines of the Pohang radiation accelerator. Fig. 10 shows a graph of measurement results of Example 1, and Fig. 11 shows graphs of measurement results of Examples 2 to 4. The wave number at the peak point of the scattering intensity obtained from the graph is q value and the quantum dot interval d calculated using the q value is as shown in Table 1 below.

division Wave number q (Å ^-1 ) Spacing d (nm) Example 1 0.02592 24.2 Example 2 0.021793 28.8 Example 3 0.024545 25.5 Example 4 0.023398 26.8

When the photovoltaic conversion films of Examples 1 to 4 according to the present invention were measured by the incineration X-ray scattering method, the q value of the peak point was determined according to the claims of the present invention, that is, Lt; ^-1 > to 0.045 <" ¹ >. 11 and Table 2, it can be seen that the quantum dots are distributed at a relatively uniform interval regardless of the content of the quantum dot-polymer beads, Polymer beads are composed of quantum dot-polymer units.

Experimental Example  2: Measurement of luminous efficiency

The light-emitting efficiency (QY) of the light-converting film prepared in Example 1 and the light-converting film prepared in Comparative Example were measured. The measurement results are shown in Fig. It can be seen from FIG. 12 that the light conversion film of the present invention including quantum dots in the bead form and the light conversion film of the comparative example in which the quantum dot is distributed over the entire area have substantially similar light emitting efficiency (QY).

Experimental Example  4: Measurement of edge deterioration degree

The light conversion film according to Example 1 and Comparative Example was allowed to stand at 60 DEG C and 90% RH for 10 days, and the degree of deterioration of the edge was examined. 13A is a photograph of the photoconversion film of Example 1 after 10 days, and FIG. 13B is a photograph of the photoconversion film of Comparative Example after 10 days. As shown in Fig. 13, no deterioration of the edge occurred in the photoconversion film of Example 1, whereas deterioration of 6 mm or more was observed at the edge portion of the photoconversion film of the comparative example.

100: liquid crystal display panel 310: quantum dot-polymer unit
200: Backlight unit 311: Quantum dot
270: photo-conversion film 312: polymer
300: Qdot-polymer beads 320: Dispersant
400: matrix resin

Claims (18)

Matrix resin; And a plurality of quantum dot-polymer beads dispersed in the matrix resin,
Each of the quantum dot-polymer beads has a cluster form in which a plurality of quantum dot-polymer unit bodies cohere with each other and are aggregated,
Wherein each of the quantum dot-polymer unit includes a polymer coating layer disposed so that a part of the quantum dot and the chain are bonded to the surface of the quantum dot and surround the quantum dot,
Wherein the quantum dots of each of the adjacent quantum dot-polymer units are spaced apart from each other by a sum of thicknesses of the polymer coating layers surrounding the quantum dots in each of the adjacent quantum dot-
The interval between the quantum dots of each adjacent quantum dot-polymer unit is from 14 nm to 112 nm,
Wherein each of the quantum dot-polymer units is in contact with other adjacent quantum dot-polymer units located in a plurality of directions centered on the quantum dot-polymer unit, and is agglomerated. delete The method according to claim 1,
Wherein the quantum dot-polymer beads have an average particle diameter of 5 to 200 占 퐉. The method according to claim 1,
And the quantum dot concentration in the quantum dot-polymer beads is 0.1 wt% to 1 wt%. The method according to claim 1,
The light conversion composite has a wave number q of a peak point of a scattering intensity graph according to a wave number measured by Small Angle X-ray Scattering of 0.0056 0.0 > A-1 < / RTI > The method according to claim 1,
Wherein the solubility parameter of the polymer contained in the polymer coating layer is 19 MPa ^1/2 to 24 MPa ^1/2 . The method according to claim 1,
Wherein the polymer contained in the polymer coating layer has a number average molecular weight of 300 g / mol to 100,000 g / mol. The method according to claim 1,
Wherein the polymer contained in the polymer coating layer is a polymer having a polar group in a main chain or a side chain. The method according to claim 1,
Wherein the polymer contained in the polymer coating layer comprises at least one selected from the group consisting of polyester, ethyl cellulose, and polyvinyl pyridine in the main chain. The method according to claim 1,
Wherein the polymer contained in the polymer coating layer is a partially oxidized polyester. The method according to claim 1,
Wherein the quantum dot-polymer beads have pores formed therein. A first barrier film;
A light conversion layer disposed on the first barrier film and formed of the light conversion composite according to any one of claims 1 to 11; And
And a second barrier film disposed on the light conversion layer. A backlight unit comprising a light source unit including a plurality of light sources and a light conversion film according to claim 12. Matrix resin;
A plurality of quantum dot-polymer beads dispersed in the matrix resin; And
And a dispersant attached to the surface of each of the quantum dot-polymer beads,
Each of the quantum dot-polymer beads has a cluster form in which a plurality of quantum dot-polymer unit bodies cohere with each other and are aggregated,
Wherein each of the quantum dot-polymer unit includes a polymer coating layer in which a part of the quantum dot and the chain are bonded to the surface of the quantum dot,
Wherein the quantum dots of each of the adjacent quantum dot-polymer units are spaced apart from each other by a sum of thicknesses of the polymer coating layers surrounding the quantum dots in each of the adjacent quantum dot-
Wherein the interval between the quantum dots of each of the adjacent quantum dot-polymer units is from 14 nm to 112 nm. 15. The method of claim 14,
The dispersant is an amphipathic organic monomolecular, amphiphilic polymer, or a combination thereof. 15. The method of claim 14,
Wherein the dispersing agent is polyvinyl alcohol. delete delete

Images