KR101327027B1 - Light converting complex, light emitting device and display device having the same and method of fabricating the same - Google Patents

Abstract

Disclosed are a light conversion composite, a light emitting device and a display device including the same, and a method of manufacturing the same. The light conversion composite includes a plurality of light conversion particles; And beads surrounding the light conversion particles and including a hydrophobic polymer.

Description

LIGHT CONVERTING COMPLEX, LIGHT EMITTING DEVICE AND DISPLAY DEVICE HAVING THE SAME AND METHOD OF FABRICATING THE SAME}

Embodiments relate to a light conversion composite, a light emitting device and a display device including the same, and a method of manufacturing the same.

Recently, a flat panel display such as a liquid crystal display (LCD), a plasma display panel (PDP), or an organic light emitting diode (OLED) has been developed in place of the conventional CRT.

The liquid crystal display device includes a thin film transistor substrate, a color filter substrate, and a liquid crystal display panel in which liquid crystal is injected between both substrates. Since the liquid crystal display panel is a non-light emitting device, a backlight unit for supplying light to the bottom surface of the thin film transistor substrate is positioned. Light transmitted from the backlight unit is adjusted according to the arrangement of liquid crystals.

The backlight unit is divided into edge type and direct type according to the position of the light source. The edge type is a structure in which a light source is provided on a side surface of the light guide plate.

The direct type is a structure that is mainly developed with the size of a liquid crystal display device being enlarged. One or more light sources are arranged on the lower surface of the liquid crystal display panel to supply light to the liquid crystal display panel.

The direct-type backlight unit has advantages in that it can utilize a larger number of light sources than the edge-type backlight unit and can secure a high luminance, but has a disadvantage that the thickness becomes thicker than the edge type in order to ensure uniformity of brightness have.

In order to overcome this problem, a quantum dot bar in which a plurality of quantum dots dispersed in a red wavelength or a green wavelength is dispersed is provided in front of a blue LED emitting blue light constituting a backlight unit, Thus, light mixed with blue light, red light and green light by a plurality of quantum dots dispersed in the quantum dot bar is incident on the light guide plate to provide white light.

At this time, when white light is provided to the light guide plate using the quantum dot bar, high color reproduction can be realized.

The backlight unit may include an FPCB (Flexible Printed Circuits Board) for transmitting and supplying LEDs and signals to one side of a blue LED emitting blue light, and an adhesive member may be further provided on the lower surface of the FPCB.

As such, when a light emitted from a blue LED is leaked, a display device for displaying an image in various forms using white light provided to the light guide plate through the quantum dot bar is widely used.

A display device to which such a quantum dot is applied is disclosed in Korean Patent Laid-Open Publication No. 10-2011-0068110.

Embodiments provide an optical conversion composite, a light emitting device, and a display device including the same and a method of manufacturing the same, which can be easily manufactured with improved reliability and durability.

In one embodiment, a light conversion composite includes a plurality of light conversion particles; And beads surrounding the light conversion particles and including a hydrophobic polymer.

A light emitting device according to an embodiment includes a light emitting unit for generating light; And a plurality of light conversion composites disposed in a path of light from the light emitting unit, wherein the light conversion composite comprises: a plurality of light conversion particles; And beads surrounding the light conversion particles and including a hydrophobic polymer.

A display device according to an embodiment includes a light source; A light conversion member on which light from the light source is incident; And a display panel to which light from the light conversion member is incident, wherein the light conversion member comprises: a plurality of light conversion particles; And beads surrounding the light conversion particles and including a hydrophobic polymer.

The method of manufacturing a light conversion composite according to an embodiment includes forming a first solution including a plurality of light conversion particles, a monomer, an emulsifier, and a first solvent, and adding a polymerization initiator to the first solution.

The light conversion composite according to the embodiment includes beads surrounding the light conversion particles. Accordingly, the light conversion particles can be protected by the beads. Therefore, the light conversion composite and the light emitting device and the display device including the same according to the embodiment may have improved reliability and durability.

In addition, the beads may be larger than the diameter of the light conversion particles. Therefore, since the light conversion particles are disposed in the bead having a larger diameter, the light conversion particles can be easily applied to a light emitting device and a display device. That is, even if the light conversion particles have a size of several nm, the light conversion particles may be easily applied to the light emitting device and the display device according to the embodiment in the form of the beads having a larger diameter.

Therefore, the light emitting device and the display device according to the embodiment can be easily manufactured by applying the light conversion composite according to the embodiment.

In addition, the light conversion composite according to the embodiment can be easily formed by emulsion polymerization.

1 is a cross-sectional view showing a light conversion composite according to an embodiment.
2 is a view showing light conversion particles according to the embodiment.
3 is a block diagram illustrating a process of manufacturing a light conversion composite according to an embodiment.
4 is a cross-sectional view illustrating a light conversion composite according to another embodiment.
5 is a block diagram illustrating a process of manufacturing a light conversion composite according to another embodiment.
6 is a perspective view illustrating a light emitting device package according to an embodiment.
FIG. 7 is a cross-sectional view taken along the line AA ′ of FIG. 6.
8 is a cross-sectional view of a light emitting diode chip.
9 is an exploded perspective view showing a liquid crystal display device according to a first embodiment.
10 is a perspective view showing a light conversion member according to the first embodiment.
FIG. 11 is a cross-sectional view taken along the line BB ′ of FIG. 10.
12 is an exploded perspective view showing a liquid crystal display according to a second embodiment.
13 is a perspective view showing a light conversion member according to the second embodiment.
FIG. 14 is a cross-sectional view illustrating a cross section taken along CC ′ in FIG. 13.
FIG. 15 is a cross-sectional view of a light guide plate, a light emitting diode, and a light conversion member according to a second embodiment.
16 is an exploded perspective view illustrating a liquid crystal display according to a third embodiment.
17 is a perspective view showing a light conversion member according to the third embodiment.
18 is a cross-sectional view taken along the line DD ′ in FIG. 17.
19 is a cross-sectional view illustrating a cross section of the light guide plate, the light emitting diode, and the light conversion member according to the third embodiment.

In the description of the embodiments, it is described that each substrate, frame, sheet, layer or pattern is formed "on" or "under" each substrate, frame, sheet, In this case, "on" and "under " all include being formed either directly or indirectly through another element. In addition, the upper or lower reference of each component is described with reference to the drawings. The size of each component in the drawings may be exaggerated for the sake of explanation and does not mean the size actually applied.

1 is a cross-sectional view showing a light conversion composite according to an embodiment. 2 is a view showing light conversion particles according to the embodiment. 3 is a block diagram illustrating a process of manufacturing a light conversion composite according to an embodiment.

1 and 2, the light conversion composite 30 according to the embodiment includes a plurality of light conversion particles 31 and beads 32.

The light converting particles 31 are disposed in the beads 32. The light conversion particles 31 may be uniformly dispersed in the beads 32. The light converting particles 31 may be inserted into the beads 32. The light conversion particles 31 may be surrounded by the bead 32. The light conversion particles 31 may be sealed by the beads 32.

The diameter R2 of the light conversion particles 31 may be about 1 nm to about 15 nm. In more detail, the diameter R2 of the light conversion particles 31 may be about 1 nm to about 10 nm. The diameter R2 of the light conversion particles 31 may be very small compared to the diameter R1 of the bead 32.

The light conversion particles 31 convert the wavelength of incident light. For example, the light conversion particles 31 may convert incident blue light into green light and red light. That is, some of the light conversion particles 31 convert the blue light into green light having a wavelength band of about 500 nm to about 599 nm, and another part of the light conversion particles 31 converts the blue light to about 600 degrees. It can be converted into red light having a wavelength band between nm and about 700 nm.

Alternatively, the light conversion particles 31 may convert the incident ultraviolet rays into blue light, green light, and red light. That is, some of the light conversion particles 31 convert the ultraviolet light into blue light having a wavelength band between about 400 nm and about 499 nm, and another part of the light conversion particles 31 converts the ultraviolet light to about 500 degrees. It can be converted into green light having a wavelength band between nm and about 599 nm. In addition, another part of the light conversion particles 31 may convert the ultraviolet light into red light having a wavelength band between about 600 nm and about 700 nm.

The light conversion particles 31 may be a plurality of quantum dots (QDs). As illustrated in FIG. 2, the quantum dot may include a core nanocrystal 33 and a shell nano crystal 34 surrounding the core nano crystal 33. In addition, the quantum dot may include an organic ligand 35 bound to the shell nanocrystals 34. In addition, the quantum dot may include an organic coating layer surrounding the shell nanocrystals 34.

The shell nanocrystals 34 may be formed in two or more layers. The shell nanocrystals 34 are formed on the surface of the core nanocrystals 33. The quantum dot may convert the wavelength of light incident to the core crystalline to the wavelength through the shell nanocrystals 34 forming the shell layer and increase the light efficiency.

The quantum dot may include at least one of a group II compound semiconductor, a group III compound semiconductor, a group V compound semiconductor, and a group VI compound semiconductor. In more detail, the core nanocrystals 33 may include Cdse, InGaP, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe, or HgS. In addition, the shell nanocrystals 34 may include CuZnS, CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe, or HgS. The diameter of the quantum dot may be 1 nm to 10 nm.

The wavelength of the light emitted from the quantum dot can be adjusted according to the size of the quantum dot. For example, a quantum dot having a small diameter may convert incident light into light having a relatively short wavelength band, and a quantum dot having a large diameter may convert incident light into light having a relatively large wavelength band.

In addition, the ligand 35 may be coupled to the quantum dot. In more detail, one end of the ligand 35 may be coupled to the quantum dot. The ligand 35 also surrounds the quantum dots. In more detail, one end of the ligand 35 may be coupled to an outer surface of the quantum dot to surround the quantum dot.

In addition, the ligand 35 serves to stabilize the unstable quantum dot after synthesis. After synthesis, a dangling bond is formed on the outer periphery, and the quantum dots may become unstable due to the dangling bonds. However, one end of the ligand 35 is in an unbound state, and one end of the unbound ligand 35 may bind with a dangling bond to stabilize the quantum dot.

The ligand 35 may include pyridine, mercapto alcohol, thiol, phosphine, or phosphine oxide. In addition, the ligand 35 may include polyethyleneimine, 3-amino propyltrimethoxy silane, mercaptoacetic acid, 3-mercaptopropyl trimethoxy silane or 3-mercaptopropionic acid, and the like. It may include. In addition, various hydrophilic organic ligands 35 may be used as the ligand 35.

Alternatively, a hydrophobic organic ligand may be used as the ligand 35.

Particularly, when the quantum dot has a size smaller than the Bohr radius of an exciton formed by electrons and holes excited by light, electricity or the like, a quantum confinement effect is generated to have a staggering energy level and an energy gap The size of the image is changed. Further, the charge is confined within the quantum dots, so that it has a high luminous efficiency.

Unlike general fluorescent dyes, the quantum dots vary in fluorescence wavelength depending on the particle size. That is, as the size of the particle becomes smaller, it emits light having a shorter wavelength, and the particle size can be adjusted to produce fluorescence in a visible light region of a desired wavelength. In addition, since the extinction coefficient is 100 to 1000 times higher than that of a general dye, and the quantum yield is also high, it produces very high fluorescence.

The quantum dot can be synthesized by a chemical wet process. Here, the chemical wet method is a method of growing particles by adding a precursor material to an organic solvent, and the quantum dots can be synthesized by a chemical wet method.

The light conversion particles 31 may be nanoparticles including a compound semiconductor. That is, the light conversion particles 31 may have a diameter of several nm to several tens of nm, and may include a group II-VI compound semiconductor.

The light conversion particles 31 may have hydrophilicity or hydrophobicity. In more detail, when the ligand 35 has hydrophilicity, the light conversion particles 31 may have hydrophilicity. When the ligand 35 has hydrophobicity, the light conversion particles 31 may have hydrophobicity.

The bead 32 receives the light conversion particles 31. The bead 32 surrounds the light conversion particles 31. In addition, the beads 32 may disperse the light conversion particles 31 therein. The bead 32 may be a medium for receiving the light conversion particles 31.

The outer surface of the bead 32 may include a curved surface. In more detail, the outer surface of the bead 32 may be formed as a curved surface as a whole. In more detail, the bead 32 may have a spherical shape.

The beads 32 are larger than the light converting particles 31. For example, the diameter R1 of the bead 32 may be about 0.05 μm to about 1 μm. In more detail, the diameter R1 of the bead 32 may be about 0.05 μm to about 0.5 μm. In more detail, the diameter R1 of the bead 32 may be about 0.05 μm to about 0.1 μm. That is, the beads 32 may be meso sized particles. That is, the bead 32 may be a matrix particle accommodating the light conversion particles 31.

The beads 32 are transparent. The bead 32 includes a polymer. In more detail, the bead 32 may be formed of a polymer. More uniquely, the beads 32 may comprise hydrophobic polymers. More specifically, examples of the hydrophobic polymer include a rubber polymer, a vinyl polymer or an acrylic polymer.

Examples of the rubber polymer include styrene butadiene rubber, acrylonitrile butadiene rubber, polychloroprene and the like. Moreover, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, etc. are mentioned as an example of the said vinyl polymer. Moreover, polymethyl methacrylate etc. are mentioned as an example of the said acryl-type polymer.

3 is a block diagram illustrating a process of manufacturing the light conversion composite 30 according to the embodiment.

Referring to FIG. 3, the light conversion composite 30 according to the embodiment may be formed by the following process.

First, the light conversion particles 31 are formed (S10). The light conversion particles 31 may be formed by a chemical wet synthesis method. The light conversion particles 31 may react the precursor of the Group II element and the precursor of the Group VI element in a solution to form a quantum dot including a Group II-VI compound semiconductor. The light conversion particles 31 may be formed by hydrothermal synthesis or the like.

For example, trioctylphosphine oxide (TOPO), trioctylphosphine (TOP), hexadecylamine (HDA) are mixed uniformly, and cadmium acetylacetonate and selenium powder are added to this mixture. Accordingly, TOP and cadmium form a complex compound, a cadmium precursor is formed, and TOP and selenium combine to form a selenium precursor.

This cadmium precursor and selenium precursor react at about 350 ° C. to form CdSe core nanocrystals 33, after which diethyl zinc and bistrimethylsilylsulfide are dispersed in TOP, and the ZnS shell at a temperature of about 200 ° C. Nanocrystals 34 are formed. Thereafter, the ligand 35 is bonded to the quantum dot.

Synthesis of the light conversion particles 31 is not limited thereto, and may be formed by various processes such as a dry process.

The light conversion particles are dispersed in a solvent such as n-octane. Thereafter, an emulsifier is added to the solution including the light conversion particles (S20). The emulsifier is added to the degree of forming micelles in the light conversion particles and subsequent monomers.

Examples of the emulsifiers include sodium dodecyl sulfate, glycol distearate, sorbitan trioleate, glycol stearate, sorbitan oleate, Sorbitan stearate or calcium stearoyl lactylate; and the like. Preferably, sodium dodecyl sulfate may be used as the emulsifier.

Thereafter, a monomer or an oligomer may be added to the solution including the light conversion particles (S30).

Examples of the monomers include styrene, butadiene, acrylonitrile, chloroprene, vinyl alcohol, vinyl chloride, vinylidene chloride or acrylate.

At least one or more of the monomers may be added to the solution.

In this case, the ratio of the light conversion particles and the monomer or oligomer may be about 1: 2 to about 1:10.

As such, water is added to the solution containing the light conversion particles and the monomer or oligomer and emulsified. That is, an emulsion comprising the light conversion particles and the monomer or oligomer is formed. The light conversion particles may be uniformly dispersed in the monomer or oligomer in the emulsion.

Thereafter, a polymerization initiator is added to the solution (S40), the temperature is raised to about 70 ° C to about 90 ° C, and a polymerization reaction occurs. Examples of the polymerization initiator include ammonium persulfate or potassium peroxodisulfate.

By the polymerization reaction, the beads may be formed, and the light conversion composite according to the embodiment may be formed. That is, by the emulsion polymerization, the light conversion composite according to the embodiment can be easily formed.

As described above, the bead 32 surrounding the light conversion particles 31 is included. Accordingly, the light conversion particles 31 may be protected by the beads 32. Thus, the light conversion composite 30 according to the embodiment may have improved reliability and durability.

In addition, the bead 32 may be larger than the diameter of the light conversion particles 31. That is, since the light conversion particles 31 are disposed in the bead 32 having a larger diameter, the light conversion particles 31 may be easily applied to a light emitting device, a display device, or the like. That is, even if the light conversion particles 31 have a size of several nm, the light conversion particles 31 may be easily applied to the light emitting device and the display device in the form of the beads 32 having a larger diameter.

4 is a view illustrating a light conversion composite according to another embodiment. 5 is a view illustrating a process of manufacturing a light conversion composite according to another embodiment. In this embodiment, reference is made to the description of the foregoing light conversion composite and a method of manufacturing the same. That is, the foregoing description of the light conversion composite and the manufacturing method may be essentially combined with the description of the present embodiment, except for the changed part.

Referring to FIG. 4, the light conversion composite 30 according to the present embodiment includes a capping portion 36. The capping portion 36 covers the beads 32. In more detail, the capping portion 36 covers the outer surface of the bead 32. The capping portion 36 is formed entirely on the outer surface of the bead 32. The capping portion 36 surrounds the outside of the bead 32. The capping part 36 may seal the bead 32.

That is, the capping part 36 may be a protective film protecting the bead 32. The capping part 36 may have a thickness of about 1 nm to 50 nm. The capping portion 36 is transparent. The material used as the capping part 36 may be an organic material or an inorganic material.

In more detail, the capping portion 36 may include a transparent metal oxide or nitride. In more detail, examples of the material used as the capping part 36 include silicon oxide, aluminum oxide, titanium oxide, silicon nitride, and the like.

Referring to FIG. 5, the light conversion composite 30 according to the present embodiment may be formed by the following process.

After the beads 32 are formed by emulsion polymerization, precursors for forming the capping portion 36 are mixed in the beads 32 and the solution in which the light conversion particles 31 are dispersed in the beads 32. do.

Examples of the material for forming the capping portion 36 include tetraethyl orthosilicate (TEOS) and ammonium hydroxide.

Accordingly, the capping part 36 may be formed around the bead 32. The thickness of the capping portion 36 may vary depending on the concentration of the precursor, the reaction time, and the reaction temperature.

The light conversion composite 30 according to the present exemplary embodiment may more effectively protect the light conversion particles 31 by using the capping part 36. Therefore, the light conversion composite 30 according to the present embodiment may have improved reliability and durability.

6 is a perspective view illustrating a light emitting device package according to an embodiment. FIG. 7 is a cross-sectional view illustrating a cross section taken along line AA ′ in FIG. 6. 8 is a cross-sectional view of a light emitting diode chip. In the description of the present light emitting device package, reference is made to the description of the foregoing light conversion composite. That is, except for the changed part, the description of the foregoing light conversion composite may be essentially combined with the description of the present embodiment.

6 to 8, a light emitting diode package according to an embodiment includes a body portion 410, a plurality of lead electrodes 421 and 422, a light emitting portion 430, a filling portion 440, and a plurality of light conversions. Composites 30.

The body part 410 accommodates the light emitting part 430, the filling part 440, and the light conversion composites 30, and supports the lead electrodes 421 and 422.

The body 410 may be formed of any one of a resin material such as PPA, a ceramic material, a liquid crystal polymer (LCP), a syndiotactic (SPS), a polyphenylene ether (PPS), and a silicon material. However, the material of the body 410 is not limited thereto. The body portion 410 may be integrally formed by injection molding, or may have a structure in which a plurality of layers are stacked.

The body portion 410 includes a cavity (C) is open at the top. The cavity C may be formed with respect to the body portion 410 by patterning, punching, cutting or etching. In addition, the cavity C may be formed by a metal mold modeled after the shape of the cavity C when the body portion 410 is molded.

The shape of the cavity C may be formed in a cup shape, a concave container shape, or the like, and the surface thereof may be formed in a circular shape, a polygonal shape, or a random shape, but is not limited thereto.

The inner surface of the cavity C may be formed as a surface perpendicular or inclined with respect to the bottom surface of the cavity C in consideration of the light distribution angle of the light emitting diode package.

The body portion 410 includes a base portion 411 and the receiving portion 412.

The base part 411 supports the receiving part 412. In addition, the base part 411 supports the lead electrodes 421 and 422. The base portion 411 may have, for example, a rectangular parallelepiped shape.

The receiving portion 412 is disposed on the base portion 411. By the receiving portion 412, the cavity C is defined. That is, the cavity C is a groove formed in the accommodation portion 412. The receiving portion 412 surrounds the cavity C. The receiving portion 412 may have a closed loop shape when viewed from the top side. For example, the receiving part 412 may have a wall shape surrounding the cavity C.

The receiving portion 412 includes an upper surface, an outer surface and an inner surface 122. The inner side surface is an inclined surface inclined with respect to the upper surface.

The lead electrodes 421 and 422 may be implemented as a lead frame, but is not limited thereto.

The lead electrodes 421 and 422 may be disposed in the body 410, and the lead electrodes 421 and 422 may be disposed to be electrically spaced apart from the bottom surface of the cavity C. Outer portions of the lead electrodes 421 and 422 may be exposed to the outside of the body portion 410.

Ends of the lead electrodes 421 and 422 may be disposed on one side of the cavity C or the opposite side of the cavity C.

The lead electrodes 421 and 422 may be formed as lead frames, and the lead frames may be formed during injection molding of the body portion 410. The lead electrodes 421 and 422 may be, for example, a first lead electrode 421 and a second lead electrode 422.

The first lead electrode 421 and the second lead electrode 422 are spaced apart from each other. The first lead electrode 421 and the second lead electrode 422 are electrically connected to the light emitting part 430.

The light emitting unit 430 includes at least one light emitting diode chip. For example, the light emitting unit 430 may include a blue light emitting diode chip or a UV light emitting diode chip.

The light emitting unit 430 may be a horizontal light emitting diode or a vertical light emitting diode chip. As shown in FIG. 8, the light emitting unit 430 includes a conductive substrate 431, a light reflecting layer 432, a first conductive semiconductor layer 433, a second conductive semiconductor layer 434, and an active layer 435. ) And a second electrode 436.

The conductive substrate 431 is made of a conductor. The conductive substrate 431 may include the light reflecting layer 432, the first conductive semiconductor layer 433, the second conductive semiconductor layer 434, the active layer 435, and the second electrode 436. I support it.

The conductive substrate 431 is connected to the first conductive semiconductor layer 433 through the light reflecting layer 432. That is, the conductive substrate 431 is a first electrode for applying an electrical signal to the first conductive semiconductor layer 433.

The light reflecting layer 432 is disposed on the conductive substrate 431. The light reflection layer 432 reflects light emitted from the active layer 435 upwards. In addition, the light reflection layer 432 is a conductive layer. Accordingly, the light reflecting layer 432 connects the conductive substrate 431 to the first conductive semiconductor layer 433. Examples of the material used as the light reflection layer 432 include a metal such as silver or aluminum.

The first conductivity type semiconductor layer 433 is disposed on the light reflecting layer 432. The first conductivity type semiconductor layer 433 has a first conductivity type. The first conductive semiconductor layer 433 may be an n-type semiconductor layer. For example, the first conductivity type semiconductor layer 433 may be an n-type GaN layer.

The second conductivity type semiconductor layer 434 is disposed on the first conductivity type semiconductor layer 433. The second conductive semiconductor layer 434 may face the first conductive semiconductor layer 433, and may be a p-type semiconductor layer. The second conductivity type semiconductor layer 434 may be, for example, a p-type GaN layer.

The active layer 435 is interposed between the first conductive semiconductor layer 433 and the second conductive semiconductor layer 434. The active layer 435 has a single quantum well structure or a multiple quantum well structure. The active layer 435 may be formed with a period of an InGaN well layer and an AlGaN barrier layer, or a period of an InGaN well layer and a GaN barrier layer, and the light emitting material of the active layer 435 may have an emission wavelength such as a blue wavelength, a red wavelength, or a green color. It may vary depending on the wavelength.

The second electrode 436 is disposed on the second conductivity type semiconductor layer 434. The second electrode 436 is connected to the second conductivity type semiconductor layer 434.

Alternatively, the light emitting unit 430 may be a horizontal LED. In this case, in order to connect the horizontal LED to the first lead electrode 421, additional wiring may be necessary.

The light emitting unit 430 may be connected to the first lead electrode 421 by a bump or the like, and may be connected to the second lead electrode 422 by a wire. In particular, the light emitting unit 430 may be directly disposed on the first lead electrode 421.

In addition, the light emitting unit 430 may be connected to the lead electrodes 421 and 422 by way of wire bonding, die bonding, or flip bonding, without being limited thereto. .

The filling part 440 is formed in the cavity C. The filling part 440 is transparent. The filling part 440 may be made of a material such as silicon or epoxy, or may include a material having a refractive index of 2 or less. The filling part 440 covers the light emitting part 430. The filling part 440 may directly contact the light emitting part 430.

In addition, a reflective layer may be formed on an inner surface of the cavity C. The reflective layer may include a highly reflective material, for example, white PSR (Photo Solder Resist) ink, silver (Ag), aluminum (Al), or the like.

The light conversion composites 30 are disposed on a path of light emitted from the light emitting part 430. For example, the light conversion composites 30 may be disposed in the cavity C. The light conversion composites 30 may be disposed adjacent to the light emitting unit 430. The light conversion composites 30 may be disposed in the filling unit 440. In more detail, the light conversion composites 30 may be uniformly dispersed in the filling unit 440. Accordingly, some or all of the light emitted from the light emitter 430 may be incident on the light conversion composites 30.

As illustrated in FIG. 7, the light conversion composites 30 may be a plurality of first light conversion composites 30a and a plurality of second light conversion composites 30b.

The first light conversion composites 30a include a plurality of first light conversion particles 31a and a first bead 32.

The first light conversion particles 31a convert light from the light emitting unit 430 into light of a first wavelength band. For example, the first light conversion particles 31a may convert blue light emitted from the light emitter 430 into green light. In more detail, the first light conversion particles 31a may convert the blue light from the light emitter 430 into light in a wavelength band of about 500 nm to about 599 nm.

The first bead 32 receives the first light conversion particles 31a. The first bead 32 surrounds the first light conversion particles 31a. The first bead 32 disperses the first light conversion particles 31a.

The second light conversion composites 30b include a plurality of second light conversion particles 31b and a second bead 32.

The second light conversion particles 31b convert light from the light emitter 430 into light of a second wavelength band. For example, the second light conversion particles 31b may convert blue light emitted from the light emitter 430 into green light. In more detail, the second light conversion particles 31b may convert blue light from the light emitter 430 into light in a wavelength band of about 600 nm to about 700 nm.

The second bead 32 receives the second light conversion particles 31b. The second bead 32 surrounds the second light conversion particles 31b. The second bead 32 disperses the second light conversion particles 31b.

In addition, when the light emitter 430 emits ultraviolet rays, the light conversion composite 30 may further include a plurality of third light conversion composites. In this case, the third light conversion composites may include third light conversion particles for converting incident ultraviolet rays into blue light.

The light conversion composites 30 receive the light emitted from the light emitter 430 and convert the wavelength. As described above, the blue light incident to the light conversion composites 30 may be converted into green light and red light.

In addition, the light conversion composites 30 may convert ultraviolet light emitted from the light emitting unit 430 into blue light, green light, and red light.

Accordingly, white light may be formed by the light converted by the light conversion composites 30 and the unconverted light. That is, blue light, green light, and red light may be combined to emit white light.

As described above, the LED package according to the embodiment may have improved reliability and durability by using the light conversion composites 30.

In addition, since the light conversion composites 30 have a diameter of a meso size, the light conversion composites 30 may be easily applied to the filler. Accordingly, the LED package according to the embodiment can be easily manufactured by easily applying the light conversion composites 30.

9 is an exploded perspective view showing a liquid crystal display device according to a first embodiment. 10 is a perspective view showing a light conversion member according to the first embodiment. FIG. 11 is a cross-sectional view taken along the line BB ′ in FIG. 10. In the description of the present liquid crystal display, reference is made to the description of the light conversion composite of the foregoing embodiments. That is, except for the changed part, the descriptions of the foregoing light conversion composite may be essentially combined with the description of the present embodiment.

9 to 11, the liquid crystal display according to the embodiment includes a backlight unit 10 and a liquid crystal panel 20.

The backlight unit 10 emits light to the liquid crystal panel 20. The backlight unit 10 may irradiate uniform light onto the bottom surface of the liquid crystal panel 20 using a surface light source.

The backlight unit 10 is disposed under the liquid crystal panel 20. The backlight unit 10 includes a bottom cover 100, a light guide plate 200, a reflective sheet 300, a light source, for example, a plurality of light emitting diodes 400, a printed circuit board 401, and a plurality of optical sheets. Field 500.

The bottom cover 100 has a top opened shape. The bottom cover 100 accommodates the light guide plate 200, the light emitting diodes 400, the printed circuit board 401, the reflective sheet 300, and the optical sheets 500.

The light guide plate 200 is disposed in the bottom cover 100. The light guide plate 200 is disposed on the reflective sheet 300. The light guide plate 200 emits light incident from the light emitting diodes 400 upward through total reflection, refraction, and scattering.

The reflective sheet 300 is disposed below the light guide plate 200. In more detail, the reflective sheet 300 is disposed between the light guide plate 200 and the bottom surface of the bottom cover 100. The reflective sheet 300 reflects the light emitted from the lower surface of the light guide plate 200 upward.

The light emitting diodes 400 are light sources for generating light. The light emitting diodes 400 are disposed on one side of the light guide plate 200. The light emitting diodes 400 generate light and enter the light guide plate 200 through a side surface of the light guide plate 200.

The light emitting diodes 400 may be blue light emitting diodes generating blue light or UV light emitting diodes generating ultraviolet light. That is, the light emitting diodes 400 may generate blue light having a wavelength band between about 430 nm and about 470 nm or ultraviolet rays having a wavelength band between about 300 nm and about 400 nm.

The light emitting diodes 400 are mounted on the printed circuit board 401. The light emitting diodes 400 are disposed under the printed circuit board 401. The light emitting diodes 400 are driven by receiving a driving signal through the printed circuit board 401.

The printed circuit board 401 is electrically connected to the light emitting diodes 400. The printed circuit board 401 may mount the light emitting diodes 400. The printed circuit board (401) is disposed inside the bottom cover (100).

The optical sheets 500 are disposed on the light guide plate 200. The optical sheets 500 change or enhance the characteristics of light emitted from the upper surface of the light guide plate 200 and supply the light to the liquid crystal panel 20. [

The optical sheets 500 may be a light conversion member 501, a diffusion sheet 502, a first prism sheet 503, and a second prism sheet 504. [

The light conversion member 501 may be disposed on an optical path between the light source 300 and the liquid crystal panel 20. For example, the light conversion member 501 may be disposed on the light guide plate 200. In more detail, the light conversion member 501 may be interposed between the light guide plate 200 and the diffusion sheet 502. The light conversion member 501 can convert the wavelength of the incident light and emit the light upward.

For example, when the light emitting diodes 400 are blue light emitting diodes, the light conversion member 501 may convert blue light emitted upward from the light guide plate 200 into green light and red light. That is, the light conversion member 501 converts a part of the blue light into green light having a wavelength band of about 500 nm to about 600 nm, and another part of the blue light has a wavelength band of about 600 nm to about 700 nm. Can be converted to red light.

Accordingly, light passing through the light conversion member 501 without conversion and light converted by the light conversion member 501 can form white light. That is, the blue light, the green light, and the red light may be combined, and the white light may be incident on the liquid crystal panel 20.

That is, the photo-conversion member 501 is an optical member that converts the characteristics of the incident light. The photo-conversion member 501 has a sheet shape. That is, the photo-conversion member 501 may be an optical sheet.

As shown in FIGS. 10 and 11, the light conversion member 501 includes a lower substrate 510, an upper substrate 520, a light conversion layer 530, and a sealing unit 540.

The lower substrate 510 is disposed under the light conversion layer 530. The lower substrate 510 is transparent and flexible. The lower substrate 510 may be in close contact with the bottom surface of the light conversion layer 530.

Examples of the material used as the lower substrate 510 may include a transparent polymer such as polyethyleneterephthalate (PET).

The upper substrate 520 is disposed on the light conversion layer 530. The upper substrate 520 is transparent and flexible. The upper substrate 520 may be in close contact with the top surface of the light conversion layer 530.

Examples of the material used as the upper substrate 520 may include a transparent polymer such as polyethylene terephthalate.

The lower substrate 510 and the upper substrate 520 sandwich the light conversion layer 530. The lower substrate 510 and the upper substrate 520 support the light conversion layer 530. The lower substrate 510 and the upper substrate 520 protect the light conversion layer 530 from an external physical shock. The lower substrate 510 and the upper substrate 520 may directly contact the light conversion layer 530.

In addition, the lower substrate 510 and the upper substrate 520 have low oxygen permeability and moisture permeability. Accordingly, the lower substrate 510 and the upper substrate 520 may protect the light conversion layer 530 from external chemical impact such as moisture and / or oxygen.

The light conversion layer 530 is interposed between the lower substrate 510 and the upper substrate 520. The light conversion layer 530 may be in close contact with the upper surface of the lower substrate 510, and may be in close contact with the lower surface of the upper substrate 520.

The light conversion layer 530 includes a matrix 531 and a plurality of light conversion composites 30.

The matrix 531 surrounds the light conversion particles 31, 532. That is, the matrix 531 uniformly disperses the light conversion particles 31 and 532 therein. The matrix 531 is transparent. That is, the matrix 531 may be formed of a transparent polymer.

The matrix 531 is disposed between the lower substrate 510 and the upper substrate 520. The matrix 531 may be in close contact with an upper surface of the lower substrate 510 and a lower surface of the upper substrate 520.

The matrix 531 may include an acrylic resin, an epoxy resin, or a silicone resin.

The light conversion composites 30 are disposed between the lower substrate 510 and the upper substrate 520. In more detail, the light conversion composites 30 may be uniformly dispersed in the matrix 531, and the matrix 531 may be disposed between the lower substrate 510 and the upper substrate 520. The light conversion composites 30 may be dispersed in the host at a concentration of about 0.5 wt% to about 20 wt%.

The light conversion composites 30 may be a plurality of first light conversion composites 30a and a plurality of second light conversion composites 30b. In addition, the light conversion composites 30 may further include a plurality of third light conversion composites.

In addition, the first light conversion composites 30a, the second light conversion composites 30b, and the third light conversion composites have substantially the same characteristics as the light conversion composites 30 in the foregoing LED package. Can have

When the light emitting diodes 400 are blue light emitting diodes that generate blue light, the first light conversion composites 30a and the second light conversion composites 30b for converting blue light into green light and red light, respectively, are used. Can be. Alternatively, when the light emitting diodes 400 are UV light emitting diodes that generate ultraviolet rays, the first light conversion composites 30a and the second light conversion composites convert ultraviolet light into blue light, green light, and red light, respectively. 30b and the third light conversion composites may be used.

The light conversion member 501 may be formed by the following process.

First, a resin composition containing quantum dots is formed. In this case, the light conversion composites 30 are uniformly dispersed in the resin composition.

Thereafter, the resin composition is uniformly coated on the lower substrate 510 and cured by heat and / or light. Accordingly, the light conversion layer 530 is formed on the lower substrate 510.

Thereafter, the upper substrate 520 is laminated on the light conversion layer 530, and a sealing part is formed. Accordingly, the light conversion member 501 may be formed.

The sealing part 540 is disposed on the side of the light conversion layer 530. In more detail, the sealing part 540 covers the side surface of the light conversion layer 530. In more detail, the sealing part 540 is also disposed on side surfaces of the lower substrate 510 and the upper substrate 520. In more detail, the sealing part 540 covers side surfaces of the lower substrate 510 and the upper substrate 520.

In addition, the sealing part 540 may be attached to side surfaces of the light conversion layer 530, the lower substrate 510, and the upper substrate 520. The sealing part 540 is in close contact with side surfaces of the light conversion layer 530, the lower substrate 510, and the upper substrate 520.

Accordingly, the sealing part 540 may seal the side surface of the light conversion layer 530. That is, the sealing part 540 is a protection part that protects the light conversion layer 530 from external chemical shock.

In addition, the light conversion member 501 may further include a first inorganic protective film and a second inorganic protective film. The first inorganic protective layer may be coated on the lower surface of the lower substrate 510, and the second inorganic protective layer may be coated on the upper surface of the upper substrate 520. Examples of the material used for the first inorganic protective film and the second inorganic protective film include silicon oxide and the like.

The diffusion sheet 502 is disposed on the light conversion member 501. The diffusion sheet 502 improves the uniformity of light passing therethrough. The diffusion sheet 502 may include a plurality of beads 32.

The first prism sheet 503 is disposed on the diffusion sheet 502. The second prism sheet 504 is disposed on the first prism sheet 503. The first prism sheet 503 and the second prism sheet 504 increase the straightness of light passing therethrough.

The liquid crystal panel 20 is disposed on the optical sheets 500. Further, the liquid crystal panel 20 is disposed on the panel guide 23. The liquid crystal panel 20 may be guided by the panel guide 23.

The liquid crystal panel 20 displays an image by adjusting the intensity of light passing through the liquid crystal panel 20. That is, the liquid crystal panel 20 is a display panel for displaying an image using light emitted from the backlight unit 10. [ The liquid crystal panel 20 includes a TFT substrate 21, a color filter substrate 22, and a liquid crystal layer interposed between the two substrates. In addition, the liquid crystal panel 20 includes polarizing filters.

Although not shown in detail in the drawings, the TFT substrate 21 and the color filter substrate 22 will be described in detail. The TFT substrate 21 defines pixels by intersecting a plurality of gate lines and data lines, A thin film transistor (TFT) is provided for each region and is connected in a one-to-one correspondence with the pixel electrodes mounted on the respective pixels. The color filter substrate 22 includes a color filter of R, G, and B colors corresponding to each pixel, a black matrix 531 bordering each of them, covering a gate line, a data line, a thin film transistor, and the like, and covering all of them. It includes a common electrode.

At the edge of the liquid crystal panel 20, a driving PCB 25 is provided to supply driving signals to the gate line and the data line.

The drive PCB 25 is electrically connected to the liquid crystal panel 20 by a chip on film (COF) 24. Here, the COF 24 may be changed to a TCP (Tape Carrier Package).

As described above, the liquid crystal display according to the embodiment may have improved reliability and durability by using the light conversion composites 30.

In addition, since the light conversion composites 30 have a diameter of a meso size, the light conversion composites 30 may be easily applied to the light conversion member. Accordingly, the liquid crystal display according to the embodiment can be easily manufactured by easily applying the light conversion composites 30.

12 is an exploded perspective view showing a liquid crystal display according to a second embodiment. 13 is a perspective view showing a light conversion member according to the second embodiment. FIG. 14 is a cross-sectional view taken along the line CC ′ in FIG. 13. FIG. 15 is a cross-sectional view of a light guide plate, a light emitting diode, and a light conversion member according to a second embodiment. In the description of the present embodiment, reference is made to the description of the foregoing embodiment. That is, the foregoing description of the liquid crystal display device may be essentially combined with the description of the present liquid crystal display device, except for the changed part.

12 to 15, the light conversion member 600 is interposed between the light emitting diodes 400 and the light guide plate 200.

The light conversion member 600 may have a shape extending in one direction. In more detail, the light conversion member 600 may have a shape extending along one side surface of the light guide plate 200. In more detail, the light conversion member 600 may have a shape extending along the incident surface of the light guide plate 200.

The light conversion member 600 receives the light emitted from the light emitting diodes 400 and converts the wavelength. For example, the light conversion member 600 may convert blue light emitted from the light emitting diodes 400 into green light and red light. That is, the light conversion member 600 converts a part of the blue light into green light having a wavelength band between about 520 nm and about 560 nm, and another part of the blue light has a wavelength band between about 630 nm and about 660 nm. Can be converted to red light.

Accordingly, the light passing through the light conversion member 600 and the light converted by the light conversion member 600 may form white light. That is, the blue light, the green light, and the red light may be combined, and the white light may be incident on the light guide plate 200.

The light conversion member 600 includes a lower substrate 610, an upper substrate 620, a light conversion layer 630, and a sealing unit 640.

The lower substrate 610 is disposed under the light conversion layer 630. The lower substrate 610 may be transparent and flexible. The lower substrate 610 may be in close contact with the bottom surface of the light conversion layer 630.

The upper substrate 620 is disposed on the light conversion layer 630. The upper substrate 620 may be transparent and flexible. The upper substrate 620 may be in close contact with the top surface of the light conversion layer 630.

In addition, the lower substrate 610 faces the light emitting diodes 400. That is, the lower substrate 610 is disposed between the light emitting diodes 400 and the light conversion layer 630. In addition, the upper substrate 620 faces the light guide plate 200. That is, the upper substrate 620 is interposed between the light conversion layer 630 and the light guide plate 200.

The lower substrate 610 and the upper substrate 620 sandwich the light conversion layer 630. In addition, the sealing part 640 covers the side surface of the light conversion layer 630. The lower substrate 610 and the upper substrate 620 support the light conversion layer 630. In addition, the lower substrate 610, the upper substrate 620, and the sealing part 640 protect the light conversion layer 630 from external physical shocks and chemical shocks.

In the liquid crystal display according to the present embodiment, the light conversion layer 630 has a relatively small size. Accordingly, in manufacturing the liquid crystal display according to the present embodiment, a small amount of light conversion particles 31a and 31b may be used.

Therefore, the liquid crystal display according to the present embodiment can be manufactured easily and at low cost by reducing the use of the light conversion particles 31a and 31b.

16 is an exploded perspective view illustrating a liquid crystal display according to a third embodiment. 17 is a perspective view showing a light conversion member according to the third embodiment. 18 is a cross-sectional view taken along the line D-D 'of FIG. 17. 19 is a cross-sectional view illustrating a cross section of the light guide plate, the light emitting diode, and the light conversion member according to the third embodiment. In the description of the present embodiment, reference is made to the description of the foregoing embodiments. That is, the foregoing description of the liquid crystal display devices may be essentially combined with the description of the present liquid crystal display device, except for the changed part.

16 to 19, the liquid crystal display according to the present exemplary embodiment includes a plurality of light conversion members 700. The light conversion members 700 correspond to the light emitting diodes 400, respectively.

In addition, the light conversion members 700 are disposed between the light emitting diodes 400 and the light guide plate 200. That is, each light conversion member 600 is disposed between the corresponding light emitting diode and the light guide plate 200.

The light conversion members 700 may have a larger planar area than the light emitting diodes 400. Accordingly, almost all of the light emitted from each light emitting diode may be incident on the corresponding light conversion member 600.

17 to 19, the light conversion members 700 include a lower substrate 710, an upper substrate 720, a light conversion layer 730, and a sealing unit 640.

Features of the lower substrate 710, the upper substrate 720, the light conversion layer 730, and the sealing unit 640 may be substantially the same as those described in the above-described embodiments.

In the liquid crystal display according to the present embodiment, the light conversion layer 730 has a relatively small size. Therefore, in manufacturing the liquid crystal display according to the present embodiment, a small amount of light conversion particles 31a and 31b may be used.

Therefore, the liquid crystal display according to the present embodiment can be manufactured easily and at low cost by reducing the use of the light conversion particles 31a and 31b.

In addition, the characteristics of each light conversion member 700 may be modified to suit the corresponding light emitting diode 400. Accordingly, the liquid crystal display according to the embodiment may have improved reliability, brightness, and uniform color reproduction.

In addition, the features, structures, effects and the like described in the embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

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, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Experimental Example 1

CdSe / ZnS quantum dots to which the hydrophobic ligand is bound are dispersed in n-octane at a concentration of about 1 wt% to form a colloidal solution. Sodium dodecyl sulfate was added to the colloidal solution in an amount of about 1 wt% as an emulsifier. In addition, styrene was added to the colloidal solution at about 5 wt%. Thereafter, the colloidal solution was added to water to form an emulsion solution. Thereafter, peroxodisulfate, a polymerization initiator, was added to the emulsion solution at about 0.5 wt% in the emulsion solution, and polymerization was performed at about 80 ° C. for about 20 hours. Then, by drying, a light conversion composite was formed.

Experimental Example 2

The light conversion complex formed in Experimental Example 1 was dissolved in tween20, tetraethyl orthosilicate and ammonium hydroxide were added to the solution at a rate of about 1 wt% and 0.5 wt%, and reacted at room temperature for 24 hours.

result

In Experimental Example 1, beads having a diameter of about 100 nm were formed, and in Experimental Example 2, beads having a diameter of about 120 nm and capping portions having a thickness of about 20 nm were formed.

Experimental Example 3

The light conversion composite formed in Experimental Example 1 was uniformly dispersed in a silicone resin and coated on a polyethylene terephthalate substrate to form a light conversion member.

Experimental Example 4

Using the light conversion composite formed in Experimental Example 2, a light conversion member was formed in the same manner as in Experimental Example 4.

Comparative Example

Using only quantum dots without using styrene and TEOS, a light conversion member was formed in the same manner as in Experiment 4.

result

After exposing the light conversion members of Experimental Examples 4 to 6 and Comparative Example to the harsh conditions of about 60 ° C./about 80% (humidity) for about 500 hours, the light conversion efficiency was compared as shown in Table 1 below. Was measured.

Experimental Example 3 Experimental Example 4 Comparative Example Decreased efficiency (%) 7% 5% 20%

As shown in Table 1, it can be seen that the light conversion members of Experimental Example 3 and Experimental Example 4 have improved reliability.

Claims (20)

A plurality of light converting particles; And
Surrounding the light conversion particles, comprising a bead comprising a hydrophobic polymer,
Adding an emulsifier to the solution comprising the light converting particles and the solvent to disperse the light converting particles in the solution and adding a monomer to the solution such that the monomer surrounds the light converting particles, A light conversion composite prepared by adding a polymerization initiator for generating a polymerization reaction of the monomer to a solution to form the beads from the monomer. The light converting composite of claim 1, wherein the beads have a diameter of 0.05 μm to 1 μm. The light conversion composite of claim 1, wherein the hydrophobic polymer is selected from a rubber polymer, a vinyl polymer, or an acrylic polymer. The light converting composite of claim 3, wherein the hydrophobic polymer is selected from styrene butadiene rubber, acrylonitrile butadiene rubber, polychloroprene, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, or polymethylmethacrylate. The light converting composite of claim 1, further comprising a capping portion surrounding an outer surface of the bead. The light converting composite of claim 1, wherein an outer surface of the bead is entirely curved. The method of claim 1, wherein the light conversion particles
Core nanocrystals;
Shell nanocrystals surrounding the core nanocrystals; And
Light conversion complex comprising a ligand bound to the shell nanocrystals. A light emitting unit generating light; And
Comprising a plurality of light conversion composites disposed in the path of light from the light emitting portion,
The light conversion composite is
A plurality of light converting particles; And
Surrounding the light conversion particles, comprising a bead comprising a hydrophobic polymer,
Adding an emulsifier to the solution comprising the light converting particles and the solvent to disperse the light converting particles in the solution and adding a monomer to the solution such that the monomer surrounds the light converting particles, A light emitting device manufactured by adding a polymerization initiator for generating a polymerization reaction of the monomer to a solution to form the beads from the monomer. The light emitting device of claim 8, wherein the bead comprises butadiene rubber-based resin. According to claim 8, Body portion for receiving the light emitting portion; And
It includes a filling portion disposed in the body portion,
The light conversion composite is disposed in the filling unit. The light emitting device of claim 8, wherein the light conversion composite further includes a capping part disposed on an outer surface of the bead and including an inorganic material. The light emitting device of claim 11, wherein the capping part comprises silicon oxide. Light source;
A light conversion member to which light from the light source is incident and including a plurality of light conversion composites; And
And a display panel on which light from the photo-conversion member is incident,
The light conversion composite is
A plurality of light converting particles; And
Surrounding the light conversion particles, comprising a bead comprising a hydrophobic polymer,
Adding an emulsifier to the solution comprising the light converting particles and the solvent to disperse the light converting particles in the solution and adding a monomer to the solution such that the monomer surrounds the light converting particles, A display device manufactured by adding a polymerization initiator for generating a polymerization reaction of the monomer to a solution to form the beads from the monomer. The method of claim 13,
The light conversion particles comprise a compound semiconductor,
The diameter of the beads is 0.05㎛ to 1㎛,
The diameter of the light conversion particles is 1nm to 15nm display device. The display device of claim 14, wherein the hydrophobic polymer comprises a rubber resin or a vinyl resin. Adding an emulsifier to a solution comprising a plurality of light converting particles and a solvent to disperse the light converting particles in the solution;
Adding a monomer to surround the light conversion particles in the solution;
And adding a polymerization initiator for generating a polymerization reaction of the monomer to the solution, thereby forming a bead surrounding the light conversion particles from the monomer. The method of claim 16, wherein the monomer is selected from styrene, butadiene, acrylonitrile, chloroprene, vinyl alcohol, vinyl chloride, vinylidene chloride, or acrylate. 17. The method of claim 16, further comprising adding a substance to the solution to form a capping portion surrounding the beads. 19. The method of claim 18, wherein said material comprises tetraethyl orthosilicate. The method of claim 16, wherein the emulsifier is sodium dodecyl sulfate.

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