KR101519362B1 - Backlight unit and light-emitting device - Google Patents

Abstract

The backlight unit includes: a light emitting element including a light emitting layer including a blue light emitting chip emitting blue light and a green phosphor emitting green light; and a light emitting element including a red light emitting particle receiving light from the light emitting element and emitting red light, Includes an optical sheet dispersed therein.

Description

BACKLIGHT UNIT AND LIGHT-EMITTING DEVICE [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit and a light emitting device, and more particularly, to a backlight unit for a display device and a light emitting device.

Generally, a display device displays a color image by passing white light emitted by a white light source through a color filter. The white light source includes a blue light-emitting diode chip that emits blue light and a light conversion layer that ultimately emits white light by using a blue light. The light conversion layer mainly includes YAG (Yttrium Aluminum Garnet), which is a phosphor.

However, since the YAG fluorescent substance has a wide range of emission spectrum over the red light wavelength band and the green light wavelength band, the light emitted by the white light source using the YAG fluorescent substance can lower the color purity of the color of the image displayed by the display device. In order to solve this problem, alternatives such as dispersing two or more kinds of phosphors in a light conversion layer or adding a pigment have been proposed, but there is a limit to increase the color purity of color.

It is an object of the present invention to provide a backlight unit for a display device having a wide color reproduction area.

Another object of the present invention is to provide a light emitting device having a novel structure.

A backlight unit according to an embodiment of the present invention includes a light emitting element and an optical sheet. The light emitting device includes a light emitting layer including a blue light emitting chip emitting blue light and a green phosphor emitting green light. The optical sheet receives light from the light emitting device, and emissive particles including a red nano emitter that emits red light are dispersed therein.

In one embodiment, the green phosphor may absorb a portion of the blue light emitted by the blue light emitting chip to emit the green light. Here, examples of the green phosphor include a silicate-based phosphor, a silicon oxynitride-based phosphor, a sulfide-based phosphor, a sialon-based phosphor, and an oxide-based phosphor.

In one embodiment, the green phosphor may be encapsulated by wax particles formed of a wax-based compound, and the fluorescent complex containing the wax particles and the green phosphor may be dispersed in the light conversion layer.

In one embodiment, the luminescent particles can include wax particles and at least one red nano emitter disposed within the wax particles.

In one embodiment, the luminescent particles cover at least two red nano-luminous bodies and further comprise an inner protective film formed of silicon oxide, and the wax particles may envelop the red nano-luminescent bodies covered by the inner protective film.

In one embodiment, the luminescent particles may further include an outer protective film covering the wax particles and formed of silicon oxide. The luminescent particles may further include a wax layer covering the outer protective layer and formed of a wax-based compound.

In one embodiment, the luminescent particles may further include an inner protective film formed of silicon oxide to cover the red nano-luminescent body.

In one embodiment, the optical sheet includes a base substrate and a light diffusion layer disposed on at least one side of the base substrate, and the luminescent particles may be dispersed in the light diffusion layer.

In one embodiment, the optical sheet includes a base substrate, a light diffusion layer disposed on one surface of the base substrate, and an optical layer formed on the opposite surface of the one surface, and the luminescent particles may be dispersed in the optical layer .

In one embodiment, the optical sheet includes a base substrate, a light diffusion layer disposed on one surface of the base substrate, and an optical layer disposed between the base substrate and the light diffusion layer, .

In one embodiment, the optical sheet includes a base substrate, a light-collecting layer disposed on one surface of the base substrate, and a light-diffusing layer disposed on the opposite surface of the one surface, As shown in FIG.

A light emitting device according to an embodiment of the present invention includes a blue light emitting chip emitting blue light and a fluorescent composite disposed on the blue light emitting chip and including wax particles and a green phosphor disposed inside the wax particles and emitting green light And a dispersed light conversion layer.

In one embodiment, the wax particles may include a polyethylene-based wax, a polypropylene-based wax, or an amide-based wax.

In one embodiment, the wax particles may be formed of a wax-based compound having an acid value of 1 mg KOH / g to 200 mg KOH / g.

In one embodiment, the wax particles may be formed of a wax-based compound having a density of 0.95 g / cm ³ or more.

The backlight unit according to the present invention can emit blue light and green light through a light emitting element and realize red light through a diffusion sheet, thereby providing white light to the display panel. That is, a red light having a full width at half maximum (FWHM) and a high power density generated from a red nano-particle of a nanoparticle and a green light having a narrow half-width generated from a green phosphor or a fluorescent complex, And white light can be realized. Thus, the color purity of the color that the white light passes through the color filter of the display panel can be improved. Thus, the color reproducibility of the display device can be improved.

1 is a cross-sectional view illustrating a backlight unit according to an embodiment of the present invention.
2 is a cross-sectional view illustrating the light emitting device shown in FIG.
3 is a cross-sectional view for explaining the diffusion sheet shown in Fig.
4 is a plan view for explaining a diffusion pattern formed in the light diffusion layer of FIG.
5 is a cross-sectional view for explaining luminescent particles dispersed in the light-diffusing layer of Fig.
6A to 6F are cross-sectional views illustrating various structures of luminescent particles.
7A to 7D are cross-sectional views illustrating a diffusion sheet included in a backlight unit according to another embodiment of the present invention.
8 is a cross-sectional view illustrating a backlight unit according to another embodiment of the present invention.
9A is a cross-sectional view for explaining the light-converging sheet of FIG.
9B is a cross-sectional view illustrating a light collecting sheet according to another embodiment of the present invention.
10 is a cross-sectional view illustrating a backlight unit according to another embodiment of the present invention.
11 is a cross-sectional view illustrating a light emitting device according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It is to be understood, however, that the intention is not to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. In the accompanying drawings, the dimensions of the structures are shown enlarged or reduced from the actual size for the sake of clarity of the present invention.

The terms "first, second," and the like can be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprises", "comprising", or "having" are used to specify that there is a stated feature, step, operation, component, It is to be understood that the foregoing does not preclude the presence or addition of one or more other features, steps, operations, elements, parts or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

In the present invention, "wax-based compound" means an organic compound having a melting point higher than room temperature at a room temperature and having a melting point, and "wax particles" &Quot; means < / RTI > a shaped or amorphous particle that constitutes a single entity. By "normal temperature" is meant a temperature within the range of about 15 ° C to about 25 ° C. In the present invention, the term "luminescence" refers to a phenomenon in which electrons in a material are transited from a ground state to an excited state by an external stimulus, and excited electrons fall back to a stable ground state. And the light corresponding to the energy difference between them.

In the present invention, light in which the peak wavelength in the luminescence spectrum belongs to the wavelength range of about 600 nm to about 660 nm is referred to as "red light", light in the wavelength range of about 430 nm to about 470 nm is referred to as "blue light" And light belonging to the wavelength band of 560 nm is referred to as "green light ".

In the present invention, the term "luminescent particle" means a particle including a nano-luminescent material therein, and is defined as a concept including not only a composite including wax particles together with a nano-luminescent material but also a nano-luminescent material itself.

Backlight unit

FIG. 1 is a cross-sectional view illustrating a backlight unit according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view illustrating the light emitting device shown in FIG. 1. Referring to FIG.

1 and 2, the backlight unit 1000 includes a light emitting device 1100, a light guide plate 1200, a reflection plate 1300, a diffusion sheet 1400, a first condensing sheet 1500, and a second condensing sheet 1600).

The light emitting device 1100 includes a frame 1110, a blue light emitting chip 1120, and a light conversion layer 1130. The blue light emitting chip 1120 is mounted in the inner space of the frame 1110 and the light switching layer 1130 is filled in the inner space of the frame 1110 to cover the blue light emitting chip 1120. The light converting layer 1130 includes a green phosphor 1132 dispersed in a light transmitting resin 1131.

The blue light emitting chip 1120 includes a light emitting diode that emits blue light. The light emitting diode may include a nitride compound. The nitride compound may include at least one nitride selected from indium (In), gallium (Ga), and aluminum (Al). For example, the nitride compound may be represented by "In _i Ga _j Al _k N", where 0? I, 0? J, 0? K, and i + j + k = 1 .

For example, the light emitting diode may have a laminated structure of an n-type semiconductor layer, an active layer and a p-type semiconductor layer, and each of the n-type semiconductor layer, the active layer, and the p-type semiconductor layer may include the nitride- have. At this time, the n-type semiconductor layer is doped with an n-type impurity, the p-type semiconductor layer is doped with a p-type impurity, and the active layer may not be doped with impurities. As a specific example, the light-emitting diode may include an n-type semiconductor layer of a double layer structure of GaN and AlGaN doped with an n-type impurity, an active layer composed of InGaN, and a p-type semiconductor layer of a double layer structure of GaN and AlGaN doped with a p- As shown in FIG.

The emission spectrum of the blue light emitted by the light emitting diode may have a half width (FWHM) of about 50 nm or less. Preferably, the emission spectrum of blue light may have a half width of about 30 nm or less.

As the light transmitting resin 1131 of the light conversion layer 1130, an epoxy resin, a silicone resin, or the like can be used.

In the light conversion layer 1130, the green phosphor 1132 dispersed in the light transmissive resin 1131 is a compound emitting green light, and absorbs blue light generated by the blue light emitting chip 1120 to generate green light . The emission spectrum of the green light emitted by the green phosphor 1132 may have a half width (FWHM) of about 80 nm or less. Preferably, the emission spectrum of the green light may have a half width of about 70 nm or less. More preferably, the emission spectrum of the green light may have a half width of about 60 nm or less.

As the green phosphor 1132, a silicate-based phosphor, a silicon oxynitride-based phosphor, a sulfide-based phosphor, a sialon-based phosphor, an oxide-based phosphor, and the like can be used. have.

The silicate-based fluorescent material may be represented by "MSi _x O _y : Re" (x and y are each independently an integer of 1 or more). Here, M represents barium (Ba), strontium (Sr), calcium (Ca), or magnesium (Mg), and these may be contained singly or in combination of two or more. In the silicate phosphor, the source consumption of M for each of Si, O and Re may have various values. Further, in the silicate phosphor, when M contains two or more elements, the elemental consumption among elements constituting M may have various values. Re is a rare earth element such as Eu, Y, La, Ce, Nd, Prommium, Sm, Gd, Dy, Ho, Er, Thr, Yb, Lu, F, Cl, Br or I, These may be included individually or in combination of two or more. When Re in the silicate phosphor contains two or more elements, the element consumption among elements constituting Re may have various values. As a specific example, Ba ₂ SiO ₄ : Eu, Ca ₂ SiO ₄ : Eu, Sr ₂ SiO ₄ : Eu, Ba ₂ SrSiO ₄ : Eu, Ca ₈ Mg (SiO ₄ ) ₄ Cl ₂ : Eu , Ca ₂ Sr ₂ MgSi ₂ O ₇ : Eu, and Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce.

The silicon oxynitride-based fluorescent material may be represented by "MSi _x O _y N _z : Re" (x, y, and z are each independently an integer of 1 or more). At this time, since M and Re are substantially the same as those described above, redundant description is omitted. Examples of the silicon oxynitride-based fluorescent material include BaSi ₂ O ₂ N ₂ : Eu, SrSi ₂ O ₂ N ₂ : Eu, CaSi ₂ O ₂ N ₂ : Eu, Ba ₃ Si ₆ O ₁₂ N ₂ : Eu Can be used.

The sulfide-based fluorescent material may be represented by "MA _x D _y : Re" (x and y each independently an integer of 1 or more). At this time, since M and Re are substantially the same as those described above, redundant description is omitted. A represents gallium (Ga), aluminum (Al), or indium (In), and these may be included singly or in combination of two or more. When A in the sulfide-based fluorescent material contains two or more elements, the element consumption among elements constituting A may have various values. D represents sulfur (S), selenium (Se) or tellurium (Te), and these may be contained individually or in combination of two or more. In the above sulfide-based fluorescent material, when D contains two or more elements, the element consumption among elements constituting D may have various values. As a specific example, in the sulfide-based phosphor is _{SrGa 2 S 4: Eu, BaGa} 2 S 4: Eu, SrAl 2 S 4: Eu There are the like can be used.

The sialon-based fluorescent material may be represented by "β-SiAlON: Re". At this time, since Re is substantially the same as that described above, a duplicate description will be omitted. As a specific example, β-SiAlON: Eu or the like may be used as the sialon-based fluorescent material.

The oxide-based fluorescent material may be represented by "MG _x O _y : Re '" (x and y are each independently an integer of 1 or more). At this time, since M is substantially the same as that described above, redundant description is omitted. G represents scandium (Sc), yttrium (Y), gadolinium (Gd), lanthanum (La), lutetium (Lu), aluminum (Al), or indium (In) . When G in the oxide-based fluorescent material contains two or more elements, the element consumption among elements constituting G may have various values. Re 'is at least one element selected from the group consisting of Ce, Ne, Prommium, Sm, Tb, Dy, Yb), fluorine (F), chlorine (Cl), bromine (Br) or iodine (I). These may be contained singly or in combination of two or more. In the oxide-based fluorescent material, when Re 'contains two or more elements, the element consumption among elements constituting Re' may have various values. As a specific example, Sr ₄ Al ₁₄ O ₂₅ : Eu, CaSc ₂ O ₄ : Ce, and SrAl ₂ O ₄ : Eu may be used as the oxide-based fluorescent material.

The diameter of the green phosphor 1132 may be about 5 [mu] m to about 55 [mu] m. The diameter of the green phosphor 1132 may be about 8 μm to about 15 μm so that the green phosphor 1132 is uniformly dispersed in the light transmitting resin forming the light conversion layer 1131. The diameter of the green phosphor 1132 is defined by a dynamic light scattering method (DLS method) calculated by a Stokes-Einstein equation with respect to a diffusion coefficient.

The light guide plate 1200 is disposed adjacent to the light emitting device 1100. The light generated by the light emitting device 1100 is incident on the light guide plate 1200 and the light emitted from the light guide plate 1200 may be incident on the diffusion sheet 1400.

The reflection plate 1300 may be disposed under the light guide plate 1200 to reflect the light leaking to the lower portion of the light guide plate 1200 toward the light guide plate 1200 to increase the light utilization efficiency.

The diffusion sheet 1400 is disposed on the light guide plate 1200 and can diffuse the light emitted from the light guide plate 1200. The diffusion sheet 1400 will be described in detail with reference to FIGS. 3, 4, and 5. FIG.

The first light collecting sheet 1500 is disposed on the diffusion sheet 1400 and the first light collecting sheet 1500 includes a light collecting pattern including a plurality of protrusions. The second light condensing sheet 1600 is disposed on the upper portion of the first light condensing sheet 1500 and the second light condensing sheet 1600 has substantially the same shape as the protruding portion formed on the first light condensing sheet 1500 And a condensing pattern including a plurality of protrusions. The condensing pattern of the first condensing sheet 1500 faces the second condensing sheet 1600 and the condensing pattern of the second condensing sheet 1600 is arranged on the backlight unit 1000, Respectively. The longitudinal direction of the condensing pattern of the first condensing sheet 1500 and the condensing pattern of the second condensing sheet 1600 may intersect with each other. In this case, the angle of intersection of the longitudinal directions of the protrusions may be about 90 °.

3 is a cross-sectional view illustrating one embodiment of the diffusion sheet shown in FIG.

Referring to FIG. 3, the diffusion sheet 1400 includes a base substrate 1410 and a light-diffusing layer 1420 formed on the base substrate 1410 and having light-emitting particles CX dispersed therein.

The base substrate 1410 may include a light incident surface on which light is incident and a light exit surface on which the incident light is emitted in opposition to the light incident surface. The base substrate 1410 is formed of a transparent material that transmits light. Examples of the transparent material include polymethylmethacrylate (PMMA) resin, polycarbonate (PC) resin, polyimide (PI) resin, polyethylene (PE) resin, polypropylene PP resin, methacrylic resin, polyurethane resin, and polyethylene terephthalate (PET) resin.

The light diffusion layer 1420 may be formed on the light incident surface of the base substrate 1410. That is, the light diffusion layer 1420 is disposed to face the light guide plate 1300. The light diffusion layer 1420 includes a diffusion pattern 1420a formed on a surface thereof.

For example, the diffusion pattern 1420a may be a continuous pattern having a shape in which a plurality of convex portions continuously extend. At this time, each of the convex portions is formed on the surface of the light diffusion layer 1420 so as to protrude toward the light guide plate 1200. For example, the projecting height of the convex portion may be about 1 占 퐉 to about 20 占 퐉, and the diameter of the convex portion may be about 1 占 퐉 to 40 占 퐉. Here, the diameter of the convex portion is defined as a maximum value of the distances between two points on the rim of the planar projection shape. The height or diameter of the convex portions may be different from each other and may have an irregular value within the above range. At this time, the convex portion may have a circular shape in a planar projection. Alternatively, the convex portion may have various shapes such as an elliptical shape or a polygonal shape in a planar projection, and shapes, projecting heights, and diameters of the respective convex portions may be different from each other.

The diffusion pattern 1420a may include a plurality of divided regions when viewed in plan, as shown in FIG. FIG. 4 is a plan view for explaining a diffusion pattern 1420a formed in the light diffusion layer 1420 of FIG. 3. The diffusion pattern 1420a corresponds to each of a plurality of irregularly arranged divided regions having a planar irregular shape As shown in Fig.

As another example, the diffusion pattern 1420a may be a continuous pattern having a shape in which a plurality of recesses are continuously connected. Each of the recesses is embedded in a direction from the surface of the diffusion sheet 1400 toward the interior of the diffusion sheet 1400. The depth or width of the recesses can be adjusted as required and the depth or width of each of the recesses can have an irregular value. The diffusion pattern may have a combination of a concave portion and a convex portion, or may be an embossing pattern.

As another example, the diffusion pattern 1420a may be a discontinuous pattern. In the discontinuous pattern, the convex portions may be spaced apart from each other, or the concave portions may be spaced apart from each other. The convex portion and the concave portion constituting the discontinuous pattern may have a dot shape when seen from a plane. The height, depth, and width of each convex or concave portion may have irregular values that are different from each other.

The luminescent particles CX are dispersed in the light diffusion layer 1420 and include a red nano emitter 20 (see FIG. 5). The red nano luminous body 20 will be described later with reference to Fig.

5 is a cross-sectional view for explaining luminescent particles dispersed in the light-diffusing layer of Fig.

Referring to FIG. 5, the luminescent particles (CX) include the red nano-luminophore 20. In the present embodiment, this means that the luminescent particles (CX) are the red nano emitters 20 themselves.

The red nano emitter 20 is a compound emitting red light, and a known nano emitter which emits red light can be used without limitation. For example, the red nano emitter 20 may include a central particle 21 and a ligand 23 bonded to the surface of the central particle 21.

The emission spectrum of the red nano emitter 20 may have a half width (FWHM) of about 70 nm or less. Preferably, the half width is about 50 nm or less, more preferably about 40 nm or less.

The core particles 21 may be composed of a group II-VI compound, a group II-V compound, a group III-V compound, a group III-IV compound, a group III-VI compound, a group IV-VI compound, or a mixture thereof . The "mixture" includes not only a simple mixture of the above compounds but also dopants doped in ternary compounds, quaternary compounds, and mixtures thereof.

Examples of Group II-VI compounds include magnesium sulphide (MgS), magnesium selenide (MgSe), magnesium telluride (MgTe), calcium sulphide (CaS), calcium selenide (CaSe), calcium telluride Strontium (SrS), strontium selenide (SrSe), strontium telluride (SrTe), cadmium sulfide (CdS), cadmium selenide (CdSe), tellurium cadmium (CdTe), zinc sulfide (ZnS), zinc selenide , Zinc telluride (ZnTe), mercury sulphide (HgS), mercury (HgSe) and mercury (HgTe).

Examples of Group II-V compounds include zinc phosphide (Zn ₃ P ₂ ), zinc diglyceride (Zn ₃ As ₂ ), cadmium phosphide (Cd ₃ P ₂ ), cadmium nonadducted (Cd ₃ As ₂ ) Cd ₃ N ₂ ), zinc nitride (Zn ₃ N ₂ ), and the like.

Examples of Group III-V compounds include boron phosphide (BP), aluminum phosphide (AlP), aluminum arsenide (AlAs), aluminum antimonide (AlSb), gallium nitride (GaN), gallium phosphide (InN), indium phosphide (InP), indium phosphide (InAs), indium antimonide (InSb), aluminum nitride (AlN), boron nitride (BN ).

Examples of Group III-IV compounds include boron carbide (B ₄ C), aluminum carbide (Al ₄ C ₃ ), gallium carbide (Ga ₄ C), and the like.

Examples of Group III-VI compounds include aluminum sulfide (Al ₂ S ₃ ), aluminum selenide (Al ₂ Se ₃ ), aluminum telluride (Al ₂ Te ₃ ), gallium sulfide (Ga ₂ S ₃ ) (Ga ₂ Se ₃ ), indium sulfide (In ₂ S ₃ ), indium selenide (In ₂ Se ₃ ), gallium telluride (Ga ₂ Te ₃ ) and indium telluride (In ₂ Te ₃ ).

Examples of Group IV-VI compounds include lead sulfide (PbS), tellurium lead (PbSe), tellurium lead (PbTe), tin sulfide (SnS), tin selenide (SnSe), and tellurium tin (SnTe).

For example, the core particles 21 may have a core / shell structure. Each of the core and the shell of the core particle 21 may be composed of the above-exemplified compounds. The above-exemplified compounds may be used alone or in combination of two or more to form the core or shell. The band gap of the compound constituting the core may be narrower than the band gap of the compound constituting the shell, but is not limited thereto. However, when the core particles 21 have a core / shell structure, the compound constituting the shell may be different from the compound constituting the core. For example, the center particle 21 may be a CdSe / ZnS (core / shell) structure having a core containing CdSe and a shell containing ZnS, a core containing InP and a shell containing ZnS. ZnS (core / shell) structure. For example, when the center particle 21 has a CdSe / ZnS (core / shell) structure, the diameter of the center particle 21 may be about 5 nm to about 8 nm. Preferably, the diameter of the central particles 21 may be from about 4.5 nm to about 6.5 nm. The diameter of the center particle 21 can be defined by a dynamic light scattering method (DLS method).

As another example, the center particles 21 may have a core / multishell structure having at least two or more shells. For example, the central particle 21 may include a core comprising CdSe, a first shell surrounding the surface of the core and containing ZnSe, and a second shell surrounding the surface of the first shell and containing ZnS, ZnSe / ZnS (core / first shell / second shell) structure. In addition, the center particle 21 may include an InP / ZnSe / ZnS (core / first shell / second shell) structure having a core containing InP, a first shell containing ZnSe, and a second shell containing ZnS Lt; / RTI >

As another example, the center particles 21 may be of a single structure, not a core / shell structure, only of a group II-VI compound or only of a group III-V compound.

Although not shown in the drawings, the core particles 21 may further include a cluster molecule as a seed. The cluster molecule is a compound acting as a seed in the process of producing the center particle 21, wherein the precursor of the compound constituting the center particle 21 grows on the cluster molecule to form the center particle 21 . Examples of the cluster molecules include various compounds disclosed in Korean Patent Publication No. 2007-0064554, but are not limited thereto.

The ligands 23 can prevent the adjacent central particles 21 from being cohered to quench each other. The ligand 23 binds to the center particle 21 and may have a hydrophobic property.

An example of the ligand 23 is an amine compound or a carboxylic acid compound having an alkyl group having 6 to 30 carbon atoms. Examples of the amine compound having an alkyl group include hexadecylamine or octylamine. Another example of the ligand 23 is an amine compound or a carboxylic acid compound having an alkenyl group having 6 to 30 carbon atoms. Alternatively, another example of the ligand 23 is a phosphine compound including trioctylphosphine, triphenolphosphine, t-butylphosphine, and the like. ); Phosphine oxide such as trioctylphosphine oxide; Pyridine, thiophene, and the like. The ligand 23 is not limited to those exemplified above, and the red nano light emitter 20 may be composed of only the center particle 21 without the ligand 23. [

Hereinafter, light emitting particles 100a, 100b, 100c, 200a, 200b, and 200c having a structure different from that of the light emitting particles CX included in the diffusion sheet 1400 will be described with reference to FIGS. 6A to 6F do. As the luminescent particles CX, at least one of the red nano emitter 20 described in FIG. 5 and the luminescent particles 100a, 100b, 100c, 200a, 200b, and 200c described in FIGS. 6A to 6F are selected Can be used.

6A to 6F are cross-sectional views illustrating various structures of luminescent particles.

6A, the luminescent particle 100a according to an exemplary embodiment includes wax particles 110 and at least one red nano light emitter 120 disposed within the wax particles 110. Referring to FIG.

The wax particles 110 are made of a wax-based compound. The wax particles 110 encapsulate the red nano emitter 120 to prevent the red nano emitter 120 from being damaged by moisture, heat, light, etc. due to external environment. As the red nano light emitter 120 is positioned inside the wax particles 110, the wax particles 110 are dispersed in the red nano light emitter 120 to form the base substrate of the optical member or the resin Can be stably dispersed.

In the present invention, the term "encapsulation" means that the red nano emitter 120 is disposed inside the wax particle 110 and the red nano emitter 120 is wrapped by the wax particles 110 it means. At this time, a van der Waals force may act between the red nano light emitter 120 and the wax particles 110.

As the wax-based compound constituting the wax particles 110, a synthetic wax in the form of a polymer, a copolymer or an oligomer may be used. For example, polyethylene-based wax, polypropylene-based wax or amide-based wax may be used as the wax-based compound.

In one embodiment, when the wax-based compound is a polyethylene-based wax or a polypropylene-based wax, the wax-based compound may include at least one of the following units represented by the following formulas (1) to (7)

[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

(7)

R ₁ , R ₃ , R ₅ and R ₇ are each independently a single bond or an alkylene group having 1 to 10 carbon atoms (* - (CH 2) _x - *, x is an integer of 1 to 10) R ₂ , R ₄ , R ₆ and R ₈ may each independently be hydrogen or an alkyl group having 1 to 10 carbon atoms, and R _a , R _b , R _c , R _d , R _e , R _f and Each R _g may independently be hydrogen or an alkyl group having 1 to 3 carbon atoms.

As specific examples, when R ₂ in Formula 1 is hydrogen, the unit of Formula 1 may include a carboxyl group. Alternatively, when R ₂ in Formula 1 is an alkyl group of 1 to 10 carbon atoms, May contain an ester group. When R ₄ in Formula 2 is hydrogen, the unit of Formula 2 may include an aldehyde group. Alternatively, when R ₄ in Formula 2 is an alkyl group of 1 to 10 carbon atoms, Ketone group. When R _{6 in} Formula 3 is hydrogen, the monomer of Formula 3 may include a hydroxy group. Alternatively, when R _{6 in} Formula 3 is an alkyl group of 1 to 10 carbon atoms, May include an ether group.

When all of R _a , R _b , R _c , R _d , R _e , R _f and R _g in formulas (1) to (7) are hydrogen, the wax-based compound may be a polyethylene wax. For example, the polyethylene wax may be a polyethylene wax (PE wax) containing only a unit in which R _g in Formula 7 is hydrogen. Alternatively, the polyethylene wax, as well as R _g is unit is hydrogen of the formula (7), in the above Chemical Formulas 1 to 6 R _a, R _b, R _c, R _d, R _e and R _f is contained in an oxygen hydrogen And may further include at least one of the monomer units. Examples of the polyethylene wax containing at least one oxygen-containing unit include oxidized polyethylene wax (ethylene oxide wax), ethylene-acrylic acid copolymer, ethylene-vinyl An ethylene-vinyl acetate copolymer, and an ethylene-maleic anhydride copolymer.

When each of R _a , R _b , R _c , R _d , R _e , R _f and R _g in the above Chemical Formulas 1 to 7 is independently a methyl group having 1 carbon atom, the wax compound is a polypropylene wax . For example, the polypropylene wax may be a polypropylene wax (PP wax) containing only a unit having R _g in the formula (7 ₎ as a methyl group. Alternatively, the polypropylene-based wax is in the above Chemical Formulas 1 to 6 R _a, R _b, R _c, R _d, R _e and R _f is contained in an oxygen hydrogen, as well as units of the R _g in the formula (2) methyl group, The polypropylene wax may further include at least one of the monomers. Examples of polypropylene waxes containing an oxygen-containing monomer include propylene-maleic anhydride copolymers and the like.

In another embodiment, when the wax-based compound is an amide-based wax, the wax-based compound may be a polymer, a copolymer, or an oligomer having an amide bond (-CONH-) as a main chain. The amide wax may include a unit having 1 to 10 carbon atoms. The amide wax may further include at least one of the oxygen-containing units represented by the above formulas (1) to (6).

When the wax-based compound includes at least one oxygen-containing unit among the units represented by the general formulas (1) to (6), the wax particles 110 may include the red nano-luminous body 120 ) Can be more stably encapsulated. When the wax-based compound includes an oxygen-containing unit, the polarity of the oxygen contained in the oxygen-containing unit causes the mutual interaction between the wax particles 110 and the metal constituting the red nano- This is because the interaction becomes stronger.

When the wax-based compound includes the unit represented by the formula (1), particularly the carboxyl group, among the oxygen-containing units, the interaction between the wax particles 110 and the red nano-luminophore 120 becomes stronger, (110) encapsulates the red nano emitter (120). Therefore, in one embodiment of the present invention, it is preferable that the wax particles 110 comprise a wax-based compound containing at least a carboxyl group as a substituent.

The wax-based compound constituting the wax particles 110 may have an acid value of about 1 mg KOH / g to about 200 mg KOH / g. In the present invention, the "acid value" of the wax-based compound refers to the number of mg of potassium hydroxide (KOH) required to neutralize 1 g of the wax-based compound. The larger the acid value of the wax-based compound, the greater the amount of the carboxyl group contained in the wax-based compound. When the acid value of the wax-based compound is less than about 1 mg KOH / g, the amount of the carboxyl group interacting with the red nano emitter 120 is very small and the red nano emitter 120 can not be stably encapsulated Lt; / RTI > If the acid value of the wax-based compound is more than about 200 mg KOH / g, the surface of the red nano-luminous body 120 may be oxidized by the carboxyl group. As a specific example, in order to stably encapsulate the red nano emitter 120, the wax-based compound constituting the wax particles 110 may have an acid value of about 5 mg KOH / g to about 50 mg KOH / g .

The wax particles 110 may be made of a wax-based compound having a high density of about 0.95 g / cm ³ or more. Since the high-density wax-based compound having a high density of about 0.95 g / cm ³ or more has a relatively high melting point as compared with the low-density wax-based compound having a low density of less than about 0.95 g / cm ³ , the wax particles 110 ) Can be improved in the light emitting particle 100a. Since the high-density wax-based compound is superior in crystallinity to the low-density wax-based compound when recrystallized, the wax particles 110 made of a high-density wax-based compound can stably encapsulate the red nano-luminophore 120 have.

One as a specific example, polyethylene (PE) wax is from about 0.95 g / cm high-density PE wax having ^three or more density (high density PE wax, HDPE wax) and low density PE wax having a density of less than about 0.95 g / cm ³ ( low density PE wax, LDPE wax), and the wax particles 110 may be formed of HDPE wax. The density of the HDPE wax may be about 1.20 g / cm ³ or less, where the melting point of the HDPE wax may be about 120 ° C to about 200 ° C. In contrast, the melting point of the LDPE wax may range from about 80 ° C to about 110 ° C. Therefore, the heat resistance of the luminescent particles 100a according to the embodiment of the present invention can be further improved than that the wax particles 110 formed of HDPE wax are formed of LDPE wax.

The wax particles 110 may be formed of a wax-based compound having a weight-average molecular weight of about 1,000 to 20,000. In the present invention, "weight average molecular weight" means an average molecular weight obtained by averaging the molecular weights of component molecular species of a polymer compound having a molecular weight distribution by a weight fraction. When the weight average molecular weight of the wax-based compound is less than about 1,000, it is difficult for the wax-based compound to exist in a solid state at room temperature. Therefore, it may be difficult to encapsulate the red nano-luminous body 120 at room temperature. When the weight average molecular weight of the wax-based compound is more than about 20,000, the recrystallization size (average diameter) of the wax-based compound is several hundreds of 탆 or more. Therefore, even when the fluorescent composite is prepared, Difficult problems can arise. In addition, when the wax-based compound has a molecular weight of more than about 20,000, the wax-based compound has a melting point of about 200 ° C or more. Therefore, in the process of encapsulating the red nano- May be damaged.

The red nano luminous body 120 is substantially the same as the red nano luminous body 20 described with reference to Fig. 3, and thus a detailed description thereof will be omitted.

The luminescent particles 100a may have various shapes and one luminescent particle 100a may include at least one red nano phosphor 120. [ For example, one red nano emitter 120 may be disposed within one wax particle 110, while two to several tens of millions of red nano emitters 120 may be disposed within one wax particle 110, May be disposed. When a plurality of the red nano light emitters 120 are disposed in one wax particle 110, the distance between the red nano light emitters 120 may be about 0.1 nm to about 10 nm. Preferably, it can be from about 0.9 nm to about 1.2 nm.

The diameter of the luminescent particles 100a may be about 50 nm to about 50 mu m. In the coating composition comprising the luminescent particles 100a, the diameter of the luminescent particles 100a may be about 0.5 μm to about 10 μm, considering the dispersibility of the luminescent particles 100a. The diameter of the luminescent particle 100a is a straight line distance between two points on the surface of the luminescent particle 100a and is a length of a virtual straight line connecting the two points while passing through the center of gravity of the luminescent particle 100a . However, when the linear distance varies depending on the positions of two points, such as the shape of an egg or the like, the diameter of the luminescent particle 100a is the maximum among the linear distances it means.

6B, luminescent particles 100b dispersed in the light diffusion layer 1420 of the diffusion sheet 1400 according to another embodiment of the present invention include wax particles 110, at least one red nano light emitter 120, And an outer protective film 130. [

The luminescent particles 100b are substantially the same as the luminescent particles 100a described in FIG. 6A except that the luminescent particles 100b further include the outer protective layer 130, and thus overlapping description will be omitted. The diameter of the luminescent particles 100b may be about 50 nm to about 50 mu m.

The outer protective layer 130 is formed on the surface of the wax particles 110 to cover the wax particles 110. The outer protective layer 130 is formed of silicon oxide (SiOx, 1? X? 2). The outer protective layer 130 may prevent the red nano emitter 120 from being damaged by moisture, heat, light, etc., together with the wax particles 110.

The outer protective layer 130 may be formed through hydrolysis and condensation of the silicon oxide precursor material. For example, the outer protective layer 130 may be formed by mixing wax particles 110, a silicon oxide precursor material, a catalyst material, and water in which red nano light emitters 120 are disposed in an organic solvent, For example, a silicon oxide. In this case, the outer protective layer 130 may include silica (SiO ₂ ).

Examples of the silicon oxide precursor material include triethoxysilane (HTEOS), tetraethoxysilane (TEOS), methyltriethoxysilane (MTEOS), dimethyldiethoxysilane, , Tetramethoxysilane (TMOS), methyltrimethoxysilane (MTMOS), trimethoxysilane, dimethyldimethoxysilane, phenyltriethoxysilane (PTEOS), phenyl Phenyltrimethoxysilane (PTMOS), diphenyldiethoxysilane, diphenyldimethoxysilane, and the like can be used.

The silicon oxide precursor material may be selected from the group consisting of halosilane, especially chlorosilane, such as trichlorosilane, methyltrichlorosilane, ethyltrichlorosilane, phenyl trichlorosilane, (eg, phenyltrichlorosilane, tetrachlorosilane, dichlorosilane, methyldichlorosilane, dimethyldichlorosilane, chlorotriethoxysilane, chlorotrimethoxysilane, chloroform, and the like. It is also possible to use chloromethyltriethoxysilane, chloroethyltriethoxysilane, chlorophenyltriethoxysilane, chloromethyltrimethoxysilane, chloroethyltrimethoxysilane, chlorophenyltriethoxysilane, Chlorophenyltri methoxysilane, and the like, or may be synthesized using polysiloxane, polysilazane, or the like.

The organic solvent may be, for example, methanol, ethanol, propanol, butanol, pentanol, hexanol, methyl cellosolve, An alcoholic solvent such as butyl cellosolve, propylene glycol, and diethtylene glycol, or toluene may be used. The organic solvent may be used alone or in combination of two or more.

As the catalyst material, an alkaline substance such as ammonia (NH ₃ ) may be used. In this case, ammonia can be used as a catalyst material in the step of forming the outer protective film 130 by mixing ammonia water (NH ₄ OH) with the organic solvent.

Meanwhile, although not shown in the drawing, the outer protective layer 130 may cover a plurality of wax particles 110. For example, the outer protective film 130 may cover at least two wax particles 110 disposed within the respective red nano emitters 120 and disposed adjacent to each other, and the wax particles 110 Can be filled with silicon oxide to form luminescent particles.

The luminescent particles 100b may further include the outer protective layer 130 as compared to the luminescent particles 100a described with reference to FIG. 6A, Heat, light, and the like.

6C, luminescent particles 100c dispersed in the light diffusion layer 1420 of the diffusion sheet 1400 according to another embodiment of the present invention include wax particles 110, at least one red nano light emitter 120 An outer protective film 130, and a wax layer 140.

The luminescent particles 100c are substantially the same as the luminescent particles 100b described with reference to FIG. 6B except that the luminescent particles 100c further include the wax layer 140. Therefore, detailed description will be omitted. The diameter of the luminescent particles 100c may be about 50 nm to about 50 mu m.

The wax layer 140 covers the surface of the outer protective layer 130. That is, the wax layer 140 surrounds the wax particles 110 covered with the outer protective layer 130. The wax layer 140 is formed of a wax-based compound. The wax-based compound constituting the wax layer 140 is substantially the same as that described for the wax-based compound constituting the wax particles 110, and thus a detailed description thereof will be omitted.

6C, the wax layer 140 covers one surface of the wax particles 110 covered with the outer protective layer 130. However, the wax layer 140 may include two or more wax particles (110). ≪ / RTI > For example, with reference to FIG. 6B, the case where both the first wax particles and the second wax particles, in which the red nano emitter 120 is disposed, are covered with the outer protective film 130, The wax layer 140 may cover the surface of the wax layer 130 again.

In addition, the wax layer 140 may cover at least two luminescent particles 100b shown in FIG. 6B. The wax-based compound forming the wax layer 140 is filled with the spacing space between the luminescent particles 100b disposed adjacent to each other, so that at least two wax particles each coated with the outer protective layer 130 are separated into a single wax layer (140) can be coated.

6C may include the wax layer 140 as compared to the luminescent particles 100b described with reference to FIG. 6B to thereby stably maintain the red nano emitter 120 And can be protected from moisture, heat, and the like.

Emitting particle 200a dispersed in the light diffusion layer 1420 of the diffusion sheet 1400 according to another embodiment of the present invention includes wax particles 210, And at least one red nano light emitter 220 and an inner overcoat 230 disposed on the substrate.

The wax particles 210 are substantially the same as the wax particles 110 described in FIG. 6A and the red nano emitter 220 is substantially the same as the red nano emitter 20 described in FIG. 5, It is omitted. The diameter of the luminescent particles 200a may be about 50 nm to about 50 mu m.

The inner protective layer 230 covers the red nano emitter 220. The inner protective layer 230 is in direct contact with the surface of the red nano emitter 220 to cover the red nano emitter 220. At this time, the red nano light emitters 220 disposed inside the wax particles 210 may be individually covered with the inner protective layer 230.

That is, one red nano light emitter 220 can be covered by one inner protective film 230. The inner protective film 230 is formed of silicon oxide, and the silicon oxide constituting the inner protective film 230 is substantially the same as the silicon oxide constituting the outer protective film 130 described with reference to FIG. 6B. do.

Although not shown in the drawings, the inner protective layer 230 may cover two or more red nano-luminous bodies 220. When two or more red nano light emitters 220 are covered by the inner protective film 230, the spacing space between the adjacent red nano light emitters 220 is limited by the silicon oxide constituting the inner protective film 230 Can be filled.

According to the above description, the luminescent particle 200a has a structure in which at least one red nano light emitter 220 is encapsulated with a wax-based compound in a state where the red nano light emitter 220 is primarily encapsulated by the inner protective layer 230 It is possible to prevent the red nano emitter 220 from being damaged by external heat, light, moisture, or the like.

6E, luminescent particles 200b dispersed in the light diffusion layer 1420 of the diffusion sheet 1400 according to another embodiment of the present invention include wax particles 210, at least one red nano light emitter 220 An inner protective film 230, and an outer protective film 240.

The luminescent particles 200b are substantially the same as the luminescent particles 200a described in Fig. 6D except that the luminescent particles 200b further include the outer protective layer 240, so that overlapping descriptions will be omitted. The diameter of the luminescent particles 200b may be about 50 nm to about 50 mu m.

The outer protective layer 240 may cover the wax particles 210 and may be formed of silicon oxide. Since the outer protective layer 240 is substantially the same as the outer protective layer 130 described with reference to FIG. 6B, a detailed description thereof will be omitted. The outer protective layer 240 may prevent the red nano emitter 220 from being damaged by moisture, heat, light, etc. together with the wax particles 210 and the inner protective layer 230.

6E, the outer protective film 240 covers one wax particle 210, but the outer protective film 240 may cover the plurality of wax particles 210. In this case, For example, the outer protective layer 240 may cover at least two wax particles 210 disposed adjacent to each other, and the spacing space between the wax particles 210 may be filled with silicon oxide, Can be formed.

6F, luminescent particles 200c dispersed in the light diffusion layer 1420 of the diffusion sheet 1400 according to another embodiment of the present invention include wax particles 210, at least one red nano light emitter 220 An inner protective layer 230, an outer protective layer 240, and a wax layer 250. The luminescent particles 200c are substantially the same as the luminescent particles 200b described in FIG. 6E except that the luminescent particles 200c further include the wax layer 250, and therefore duplicate detailed descriptions are omitted. The diameter of the luminescent particles 200c may be about 50 nm to about 50 mu m.

The wax layer 250 may cover the outer protective layer 240. The wax layer 250 is formed of a wax-based compound. The wax-based compound constituting the wax layer 250 is substantially the same as the wax-based compound described with reference to FIG. 6A, and thus a detailed description thereof will be omitted.

6F, the wax layer 250 may cover one wax particle 210 whose surface is covered with the outer protective layer 240, or may be formed by the outer protective layer 240, A plurality of covered wax particles 210 can be coated.

The luminescent particles 200c encapsulate the wax particles 210 with the outer protective layer 240 and the wax layer 250 so that the red nano luminous body 220 can absorb external heat, And the like can be prevented from being damaged. In some cases, in addition to the luminescent particles 200c shown in Fig. 6F, a luminescent particle encapsulated by multiple layers can be produced by repeatedly laminating a silicon oxide film and a wax layer.

3 illustrates an example of a diffusion sheet disposed on the light incident surface of the base substrate 1410 such that the light diffusion layer 1420 faces the light emission surface of the light guide plate 1200. However, May be disposed on the light exit surface of the base substrate 1410 so as to face the first light condensing sheet 1500. [

Although not shown in the drawing, luminescent particles having a structure in which the red nano-luminescent material 20 shown in Fig. 5 is covered with the inner protective film 230 described in Fig. 6D can be used as luminescent particles. The red nano light emitter 20 can be protected from moisture, heat, light, and the like due to the external environment by the inner protective film 230 formed of silicon oxide.

According to the backlight unit 1000 according to the present invention described with reference to FIGS. 1 to 5 and 6A to 6F, blue light and green light are realized through the light emitting device 1100 and red light is emitted through the diffusion sheet 1400 Thereby providing white light to the display panel. The white light provided by the backlight unit according to the present invention is a red light having a full width at half maximum (FWHM) and a high power density and a green phosphor 1132 generated from blue light, red nano light emitters 20, 120 and 220, And the color purity of the color can be improved. As a result, the color reproducibility of the display device can be improved.

Hereinafter, the backlight unit according to another embodiment of the present invention will be described. Each of the backlight units according to another embodiment of the present invention is substantially the same as the backlight unit described in Fig. 1 except for the diffusion sheet 1400. Fig. Therefore, overlapping detailed descriptions will be omitted, and diffusion sheets having differences will be described with reference to Figs. 7A to 7D.

7A to 7D are cross-sectional views illustrating a diffusion sheet included in a backlight unit according to another embodiment of the present invention.

Referring to FIG. 7A, a diffusion sheet 1402 included in a backlight unit according to another embodiment of the present invention includes a base substrate 1410 and light diffusion layers 1421 and 1422.

The light diffusion layers 1421 and 1422 are formed on both sides of the base substrate 1410 and diffusion patterns 1421a and 1422a are formed on the surfaces of the light diffusion layers 1421 and 1422. Since the diffusion patterns 1421a and 1422a are substantially the same as those described with reference to FIG. 3, a detailed description will be omitted. However, each of the diffusion patterns 1421a and 1422a may have the same structure or shape, or may have different structures or shapes. In other words, in FIG. 7A, the diffusion patterns 1421a and 1422a have a continuous pattern having substantially the same structure. However, the diffusion patterns 1421a and 1422a may be continuous patterns having different structures, or one may have a continuous pattern, Lt; / RTI >

Light emitting particles CX are dispersed in the light diffusion layers 1421 and 1422, respectively. Each of the emissive particles CX includes at least one red nano emitter and the emissive particles CX are formed only of the red nano emitter described in Fig. 5, the luminescent particles described in Figs. 6A to 6F, And may have any one structure selected from the coated red nano emitters. For example, the light emitting particles CX dispersed in each of the light diffusion layers 1421 and 1422 may have the same structure. Alternatively, the luminescent particles CX dispersed in each of the light diffusion layers 1421 and 1422 may be selected from any one of the luminescent particles described in Figs. 5, 6A to 6F, and the red nano luminescent coated only with the inner protective layer And may have different structures from each other.

Referring to FIG. 7B, a diffusion sheet 1403 included in a backlight unit according to another embodiment of the present invention includes a base substrate 1410, a light diffusion layer 1420, and an optical layer 1430. The light diffusion layer 1420 is disposed so as to face the light output surface of the light guide plate 1200 and the optical layer 1430 is disposed to face the first light condensing sheet 1500.

The optical layer 1430 is formed on the light exit surface of the base substrate 1410 and includes light emitting particles CX including a red nano emitter. Since the optical layer 1430 is substantially the same as the light diffusion layer 1420 described in FIG. 3 except that the surface is a flat surface, a detailed description will be omitted.

The light diffusion layer 1420 is formed on the light incident surface of the base substrate 1410. The light diffusion layer 1420 includes a diffusion pattern 1420a formed on the surface thereof. The diffusion pattern 1420a may be substantially the same as the continuous pattern including the plurality of convex portions described in Fig. Alternatively, the diffusion pattern 1420a may be a continuous pattern including a plurality of recesses, or may be a discontinuous pattern including a convex portion or a concave portion. The light-diffusing layer 1420 does not include the luminescent particles (CX), but merely functions to diffuse light.

7B, the surface of the optical layer 1430 is shown as being flat, but the optical layer 1430 may be replaced with the light diffusing layer 1422 described in FIG. 7A. That is, a light diffusion layer including a diffusion pattern is formed on both surfaces of the base substrate 1410, and the light emitting particles CX may be dispersed only in one of the light diffusion layers.

7B, the diffusion sheet 1403 is disposed so that the light diffusion layer 1420 faces the first light condensing sheet 1500 and the optical layer 1430 faces the light guide plate 1200 As shown in FIG.

Referring to FIG. 7C, a diffusion sheet 1404 included in a backlight unit according to another embodiment of the present invention includes a base substrate 1410, an optical layer 1430, and a light diffusion layer 1420. The diffusion sheet 1404 may be disposed on the light guide plate 1200 such that the light diffusion layer 1420 faces the light guide plate 1200. That is, the optical layer 1430 and the light diffusion layer 1420 are formed on the light incident surface of the base substrate 1410, and the light exit surface of the base substrate 1410 is exposed, .

The optical layer 1430 is substantially the same as the optical layer 1430 described in FIG. 7B except that it is disposed between the base substrate 1410 and the light-diffusing layer 1420. Therefore, redundant detailed description will be omitted.

The light-diffusing layer 1420 is formed on the optical layer 1430. The light-diffusing layer 1420 does not include the luminescent particles CX but merely diffuses light, which is substantially the same as that described with reference to FIG. 7B, so that a detailed description thereof will be omitted.

Although not shown in the drawing, the diffusion sheet 1404 may further include a light diffusion layer formed on the light exit surface of the base substrate 1410. A diffusion pattern having substantially the same shape as the diffusion pattern 1420a of the light diffusion layer 1420 formed on the light incident surface may be formed on the surface of the light diffusion layer formed on the light emission surface.

The diffusion sheet 1404 may be disposed on the light guide plate 1200 such that the light diffusion layer 1420 faces the first light condensing sheet 1500.

7D, a diffusion sheet 1405 included in a backlight unit according to another embodiment of the present invention includes a base substrate 1410, optical layers 1431 and 1432, and light diffusion layers 1421 and 1422 do.

The optical layers 1431 and 1432 are disposed on both sides of the base substrate 1410 and include light emitting particles CX. The light emitting particles (CX) include a red nano emitter.

Each of the light diffusion layers 1421 and 1422 is formed on the optical layers 1431 and 1432 and includes diffusion patterns 1421a and 1422a. The light-diffusing layers 1421 and 1422 are layers for simply diffusing light without the light-emitting particles CX.

The diffusion sheet 1405 has the diffusion sheet 1404 described in FIG. 7C except that the optical layer 1432 and the light diffusion layer 1422 are formed on the light emission surface as well as the light incident surface of the base substrate 1410. [ . Each of the optical layer 1432 and the light diffusion layer 1422 formed on the light output surface of the base substrate 1410 has an optical layer 1431 and a light diffusion layer 1421 formed on the light incident surface of the base substrate 1410, . Therefore, redundant detailed description will be omitted.

On the other hand, the luminescent particles (CX) contained in each of the optical layers 1431 and 1432 may include red nano emitters described in Fig. 5, luminescent particles described in Figs. 6A to 6F, and red nano luminescent And may have the same structure or different structure from each other.

In the light emitting device 1100, the green phosphor 1132 is dispersed in the light conversion layer 1130 and the diffusion sheet 1400 includes the light emitting particles CX including the red nano light emitting material, A portion of the green light generated in layer 1130 may excite the red nano emitter. That is, the red nano emitter may be excited by not only the blue light provided by the blue light emitting chip 1120 but also the green light generated from the green phosphor 1132. In addition, as the light generated from the blue light emitting chip 1120 primarily reaches the green phosphor 1132, the power density of the green light emitted by the green phosphor 1132 can be maximized .

Hereinafter, the backlight units according to still another embodiment of the present invention will be described.

FIG. 8 is a cross-sectional view illustrating a backlight unit according to another embodiment of the present invention, and FIG. 9A is a cross-sectional view illustrating the light condensing sheet of FIG.

8 and 9A, the backlight unit 1001 includes a light emitting device 1100, a light guide plate 1200, a reflection plate 1300, a diffusion sheet 1406, a first condensing sheet 1501, and a second condensing sheet 1600). The diffusion sheet 1406 and the first light-condensing sheet 1501 are substantially the same as the backlight unit described in FIG. Therefore, redundant detailed description will be omitted.

The diffusion sheet 1406 may have a structure of any one of the diffusion sheets described in FIGS. 3 and 7A to 7D. Alternatively, the diffusion sheet 1406 may be a conventional diffusion sheet, which has a structure of any one of the diffusion sheets described with reference to FIGS. 3, 7A to 7D, and does not include the light emitting particles (CX) .

The first light-condensing sheet 1501 includes a base substrate 1510, a light-collecting layer 1520, and a light-diffusing layer 1530. The first light condensing sheet 1501 is disposed on the diffusion sheet 1406 such that the light condensing layer 1520 faces the second light condensing sheet 1600 and the light diffusion layer 1530 faces the diffusion sheet 1406. [ .

The base substrate 1510 is formed of a transparent material. The transparent material is substantially the same as the transparent material forming the base material 1410 of the diffusion sheet 1400 described in Fig. Therefore, redundant detailed description will be omitted.

The light-collecting layer 1520 is formed on one side of the base substrate 1510. The condensing layer 1520 includes a condensing pattern 1520a formed on the surface thereof. The light condensing pattern 1520a is formed to have a sectional shape that can refract light incident from the base substrate 1510 in a vertical direction.

For example, the light collecting pattern 1520a may include a plurality of protrusions, and each of the protrusions may have a triangular cross section. The protrusions may extend in a first direction and may be continuously arranged along a second direction that intersects the first direction. For example, each of the protrusions may have a triangular prism shape having a constant height. Alternatively, the height of each of the protrusions may vary along the first direction. In this case, the height of the protruding portion may be changed linearly along the first direction or non-linearly. Furthermore, the height of the projection may be varied to have a predetermined period, but may vary irregularly. In this case, the heights of the respective projections may be changed independently of each other. The vertex angle of each projecting portion constituting the condensing pattern may be about 90 nm, but may be appropriately adjusted as necessary. When the height of the protrusion changes along the first direction, the vertex angle may be changed according to the position.

The light diffusion layer 1530 is formed on the other surface of the base substrate 1510 opposite to the one surface on which the light-collecting layer 1520 is formed. The light-diffusing layer 1530 includes luminescent particles CX. The light emitting particles (CX) include a red nano emitter. The light emitting particles CX may have a structure selected from the red nano emitters described in FIG. 5, the structure in which the inner nano emitter is surrounded by the inner protective layer, and the light emitting particles illustrated in FIGS. 6A through 6F. The light diffusion layer 1530 may include an optical pattern 1530a formed on a surface thereof. The optical pattern 1530a may include a continuous pattern including a plurality of convex portions described in FIG. 3, or a continuous pattern including a plurality of concave portions, or a discontinuous pattern including convex portions or concave portions.

Although the first light collecting sheet 1501 is described as an example in FIG. 9A, the second light collecting sheet 1600 disposed on the first light collecting sheet 1501 may have substantially the same structure as the first light collecting sheet 1501 Lt; / RTI > For example, if the first and second light collecting sheets 1501 and 1600 have the structure described in FIG. 9A, or if only one of the first and second light collecting sheets 1501 and 1600 Structure.

9B is a cross-sectional view illustrating a light collecting sheet according to another embodiment of the present invention.

Referring to FIG. 9B, the first light-condensing sheet 1502 included in the backlight unit according to another embodiment of the present invention includes a base substrate 1510, a light-collecting layer 1521, and a light-diffusing layer 1531.

The first light-condensing sheet 1502 may be formed in the same manner as the light-condensing sheet 1502 except that the light-collecting layer 1521 includes luminescent particles (CX) and the light-diffusing layer 1531 does not include the luminescent particles (CX) Is substantially the same as that of the first light collecting sheet 1501. Therefore, redundant detailed description will be omitted. The first light collecting sheet 1502 is disposed on the diffusion sheet 1406 such that the light collecting layer 1521 faces the second light collecting sheet 1600 and the light diffusing layer 1531 faces the light diffusing sheet 1406, Lt; / RTI >

The luminescent particles (CX) include a red nano emitter, a structure including the red nano emitter described in Fig. 5, a structure in which the red nano emitter is surrounded by the inner protective layer, and a structure selected from any one of the luminescent grains described in Figs. 6A to 6F Lt; / RTI >

Although the first light collecting sheet 1502 is illustrated in FIG. 9B, the second light collecting sheet 1600 disposed on the first light collecting sheet 1502 may be substantially the same as the first light collecting sheet 1502 It can have the same structure. For example, if both the first and second light converging sheets 1502 and 1600 have the structure described in FIG. 9B, or if only one of the first and second light converging sheets 1502 and 1600 Structure.

On the other hand, in the light collecting sheets 1501 and 1502 shown in Figs. 9A and 9B, each light collecting sheet is sandwiched between the base substrate 1510 and the light collecting layers 1520 and 1521, And an optical layer formed on at least one of the light diffusion layers 1530 and 1531. In this case, the luminescent particles CX may be dispersed in the optical layer, not in the light-collecting layers 1520 and 1521 and the light-diffusing layers 1530 and 1531. Alternatively, the luminescent particles (CX) may be dispersed in the optical layer together with the light-collecting layers 1520 and 1521 and the light-diffusing layers 1530 and 1531.

10 is a cross-sectional view illustrating a backlight unit according to another embodiment of the present invention.

Referring to FIG. 10, the backlight unit 1002 includes a light emitting device 1100, a light guide plate 1200, a reflection plate 1300, and a light condensing sheet 1503. Each of the light emitting device 1100, the light guide plate 1200, and the reflection plate 1300 of FIG. 10 is substantially the same as that described in FIG. Therefore, redundant detailed description will be omitted.

The light condensing sheet 1503 has substantially the same structure as that of the light condensing sheet 1501 described in FIG. 9A, and the light guide plate 1200 faces the light condensing layer 1520 and the light diffusing layer 1530 faces the backlight unit 1002, The light condensing sheet 1503 is disposed on the light guide plate 1200 so as to face the display panel disposed on the light guide plate 1200. [ The light collecting layer 1520 is arranged to face the light guide plate 1200 to replace the diffusion sheet 1406 and the first and second light converging sheets 1501 and 1600 described in FIG. 8 with the light converging sheet 1503 .

9B, the light guide plate 1200 faces the light-collecting layer 1521 and the light-diffusing layer 1531 faces the light-collecting layer 1521. The light-collecting sheet 1503 has a structure substantially identical to that of the light- The light condensing sheet 1503 is disposed on the light guide plate 1200 so as to face a display panel disposed on the light guide plate 1002.

The diffusion sheet 1406 and the first and second condenser sheets 1501 and 1600 described with reference to FIG. 8 may be replaced with the condenser sheet 1503 by arranging the condenser layer 1521 so as to face the light guide plate 1200 .

According to the above description, light emitting particles (CX) including a red nano emitter are applied to at least one of the diffusion sheet and the light collecting sheet, and the light emitting element 1100 includes a blue light emitting chip and a green phosphor, It is possible to improve the color purity of color that appears through the color filter of the display panel. Thus, the color reproducibility of the display device can be improved.

Light emitting element

11 is a cross-sectional view illustrating a light emitting device according to another embodiment of the present invention.

Referring to FIG. 11, the light emitting device 1102 includes a frame 1110, a blue light emitting chip 1120, and a light conversion layer 1130 '. The light emitting device 1102 shown in FIG. 9 is substantially the same as that described in FIG. 2 except that the light converting layer 1130 'includes a fluorescent complex 1134. Therefore, duplicate detailed explanations are omitted.

The fluorescent composite 1134 includes wax particles 1133 and green phosphors 1132 disposed inside the wax particles 1133. That is, the surface of the green phosphor 1132 is covered with the wax particles 1133.

The wax particles 1133 of the fluorescent composite 1134 are formed of a wax-based compound. The wax-based compound is substantially the same as the wax-based compound forming the wax particles 110 described in Fig. 6A. Therefore, redundant detailed description will be omitted.

The green phosphor 1132 is a compound which is dispersed in the light transmitting resin 1131 of the light converting layer 1130 'and emits green light. The green phosphor 1132 is substantially the same as that described with reference to FIG. 2, so a detailed description thereof will be omitted.

The diameter of the fluorescent complex 1134 may be about 10 탆 to about 70 탆. In order for the fluorescent composite 1134 to be uniformly dispersed in the light-transmitting resin, the diameter of the fluorescent composite 1134 may be about 15 탆 to about 35 탆. The diameter of the fluorescent complex 1134 is defined to be substantially equal to the diameter of the luminescent particles 100a.

In the light emitting device 1102 according to the present invention described with reference to FIG. 11, the fluorescent composite 1134 emitting green light is easily dispersed in the light transmitting resin 1131 in the process of forming the light converting layer 1130 ' . In addition, the fluorescent composite 1134 has good dispersion stability with respect to the light transmitting resin 1131. Therefore, even if the light emitting element 1102 is driven for a long time, the green phosphor 1132 is prevented from aggregating, and the light emission spectrum generated by the light emitting element 1102 can be stably maintained. Since the green fluorescent material 1132 is covered with the wax particles 1133, the fluorescent composite 1134 is protected from the external environment such as moisture, heat, and light, and can stably emit light for a long time without deteriorating performance .

The light emitting device 1102 illustrated in FIG. 11 may be used in place of the light emitting device 1100 of the backlight unit illustrated in FIG. 1 to configure a backlight unit according to an embodiment of the present invention.

Preparation of measurement samples

[Preparation of measurement sample 1]

A kit and B kit of OE-6630 (trade name) purchased from Dow Corning Incorporated (USA) were mixed in a ratio of 1: 4 by using a green fluorescent substance LP-F525 (trade name) purchased from LWB Was mixed with the thermosetting silicone resin to prepare Sample 1 for measurement.

[Preparation of measurement sample 2]

Measurement sample 2 was prepared in substantially the same manner as in the production method of measurement sample 1, except that LP-F530 (trade name) purchased from LWB (trade name, Germany) was used as a green phosphor.

[Preparation of measurement sample 3]

Measurement sample 3 was prepared in substantially the same manner as in the production method of measurement sample 1, except that ALONBRITE (trade name) purchased from DENKA (trade name, Japan) was used as the green phosphor.

[Preparation of Measurement Sample 4]

First, 20 mg of Oxidized HDPE Wax (trade name: Licowax PED 136 wax, Clariant, Switzerland) having an acid value of about 30 mg KOH / g as a wax compound was mixed with 1 ml of toluene Then, the wax-based compound was dissolved by raising the temperature to about 120 ° C to prepare a wax solution.

To the wax solution, 20 mg of a green fluorescent substance LP-F525 (trade name), purchased from LWB (trade name, Germany), and toluene mixed with 1 mL of toluene were added and mixed. The mixed solution of the wax solution and the toluene solution was cooled to room temperature to prepare a dispersion solution in which the fluorescent composite containing the wax particles and the green phosphor was dispersed.

The dispersion solution thus prepared was mixed with a thermosetting silicone resin mixed in a ratio of A kit and B kit of OE-6630 (trade name) purchased from Dow Corning Incorporated (USA) to prepare a measurement sample 4 Respectively.

[Preparation of Measurement Sample 5]

Measurement sample 5 was prepared in substantially the same manner as the production method of measurement sample 4, except that LP-F530 (trade name) purchased from LWB (trade name, Germany) was used as a green phosphor.

[Preparation of measurement sample 6]

Measurement sample 6 was prepared in substantially the same manner as in the production method of measurement sample 4, except that ALONBRITE (trade name) purchased from DENKA (trade name, Japan) was used as a green phosphor.

Experiment 1 - Evaluation of dispersion stability

(Transmittance immediately after dispersion) and 5 days after the measurement samples 1 to 6 were prepared using Cary-4000 (trade name, Agilent, USA) for each of the measurement samples 1 to 6 Permeability (permeability after 5 days) was measured. The dispersion stability was calculated using the above "transmittance immediately after dispersion" and "transmittance after 5 days ".

division Immediate after dispersion
Permeability (%) After 5 days
Permeability (%) Dispersion stability (%) Measurement sample 1 29 85 56 Measurement sample 2 28 87 59 Measurement Sample 3 29 84 55 Measurement Sample 4 30 37 7 Measurement sample 5 29 38 9 Measurement sample 6 28 38 10

In this experiment, the "transmittance immediately after dispersion" and "transmittance after 5 days" mean an arithmetic mean value (%) of transmittances according to wavelengths within a visible light wavelength range of about 400 nm to about 700 nm.

The dispersion stability values in Table 1 were calculated by calculating the difference between the value of "Permeability immediately after dispersion" (%) and the value of "Permeability after 5 days" (%). When the dispersion stability of the measurement samples 1 to 6 is good, the dispersion stability value becomes small because the permeability does not change greatly even if the time elapses, and when the dispersion stability of the measurement samples 1 to 6 is poor, The phosphor or the fluorescent complex is precipitated to increase the transparency of the silicone resin, and as a result, the dispersion stability value becomes large.

Referring to Table 1, when the size of the green phosphor is taken into account, it is found that the dispersion stability of the measurement samples 1 to 6 is generally good. In particular, it can be seen that the measurement samples 4 to 6 have excellent dispersion stability. Although the dispersion stability of the measurement samples 1 to 3 is larger than that of the measurement samples 4 to 6, the dispersion stability is relatively poor. However, even if the dispersion stability is about 50% to 60% But it is not. However, the transmittance immediately after the dispersion of each of the measurement samples 1 to 6 was substantially similar but the transmittance after 5 days of the measurement samples 4 to 6 was almost unchanged, while the measurement samples 1 to 3 had the higher transmission after 5 days , That is, in the measurement samples 1 to 3, a part of the green phosphor is precipitated and the transparency is increased, it can be seen that when the green phosphor is encapsulated with the wax-based compound as in the measurement samples 4 to 6, the dispersion stability is remarkably improved .

Experiment 2 - Evaluation of ultraviolet stability and heat / moisture stability

The green phosphors LP-F525 (trade name) and LP-F530 (trade name) purchased from LWB (company name, Germany) and the green phosphor ALONBRITE (trade name) purchased from DENKA Respectively.

In addition, fluorescent complexes 1, 2 and 3 in a powder state substantially identical to the fluorescent complexes contained in each of the measurement samples 4 to 6 were prepared.

The first quantum efficiency (QYT1, unit:%) was measured for each of the green phosphors and the fluorescent complexes 1 to 3 using an absolute quantum efficiency meter (trade name: C9920-02, HAMAMATSU, Japan).

The first quantum efficiency (QYT1, unit:%) was measured, and the green fluorescent material and a fluorescent composite 1-3 radiation intensity of about 1.4 mW / cm ² of ultraviolet (UV) center wavelength of 365nm for each , The second quantum efficiency (QYT2, unit:%) after irradiation for 480 hours under a severe condition of about 2,419.2 J / cm ² was measured.

After measuring the first quantum efficiency (QYT1, unit:%), each of the green phosphors and the fluorescent complexes 1 to 3 was allowed to stand for 480 hours under a severe condition of a temperature of 85 DEG C and a relative humidity of 85% And the third quantum efficiency (QYT3, unit:%) was measured.

The difference between the first quantum efficiency and the second quantum efficiency (ΔQY1 = QYT1-QYT2, unit:%) was calculated to evaluate the ultraviolet stability of each of the green fluorescent substance and the fluorescent conjugate, 3 Quantum efficiency (ΔQY2 = QYT1-QYT3, unit:%) was calculated to evaluate the heat / moisture stability of the green phosphors and the fluorescent complexes 1 to 3. The results are shown in Table 2.

division Ultraviolet stability
(? QY1,%) Heat / moisture stability
(? QY2,%) LP-F525 2.9 3.5 LP-F530 3.1 4.2 ALONBRITE 3.4 4.3 Fluorescent complex 1 1.3 1.8 Fluorescent complex 2 1.4 2.1 Fluorescent Complex 3 1.7 2.3

Referring to Table 2, it can be seen that the three types of phosphors and fluorescent complexes 1 to 3 have ultraviolet stability and heat / moisture stability of about 5% or less as a whole, and are stable against ultraviolet rays or heat / moisture have. In particular, it can be seen that the fluorescent complexes 1 to 3 have superior ultraviolet stability and heat / water stability as compared with the three kinds of phosphors themselves. That is, when a green phosphor is encapsulated using a wax-based compound, ultraviolet stability and heat / water stability are remarkably improved as a whole.

Hereinafter, the method of manufacturing the backlight unit according to the present invention described above and the evaluation results of the characteristics thereof will be described.

Fabrication of Backlight Unit

[Example 1]

(1) Fabrication of light emitting device

A thermosetting silicone resin having a green phosphor dispersed on a blue light emitting chip was molded and cured at 150 캜 for 2 hours to prepare a light emitting device.

As the blue light emitting chip, a blue light emitting chip having an emission peak at about 444 nm purchased from Nichia Corp. (Japan) was used. As the green phosphor, green phosphor LP (trade name, manufactured by LWB) -F525 (trade name) was used. As the thermosetting silicone resin, thermosetting silicone resin mixed with A kit and B kit of 1: 4 ratio of OE-6630 (trade name) purchased from Dow Corning Corporation Respectively.

(2) Fabrication of light guide plate

0.5 part by weight of a benzotriazole-based ultraviolet absorber (trade name: Tinuvin-329, BASF, Germany) and 0.5 part by weight of a hindered amine light stabilizer (trade name: Tinuvin-770, BASF, Germany) were added to 100 parts by weight of a methyl methacrylate polymer. And 0.5 part by weight of a polypropylene resin were mixed and extruded using a sheet extruder to prepare a pellet-shaped resin using an extruder (inner diameter: 27 mm, L / D: 40, Leistritz. .

(3) Production of diffusion sheet

A solution of about 10 mg of a CdSe red nano luminescent material (Nanodot-HE-610, QD solution, Korea) dispersed in 1 ml of toluene was mixed with urethane acrylate purchased from BASF Co., Ltd. (Germany) (2,4,6-trimethylbenzoyl) phosphine oxide (TPO). The photoinitiator was mixed with about 0.8 part by weight based on 100 parts by weight of urethane acrylate. Then, toluene was removed using an evaporator to prepare a coating composition in which urethane acrylate, a red nano light-emitting material and a photoinitiator were mixed.

The above coating composition was coated on a transparent base substrate (trade name: XU42, Doreisha, Japan) having a thickness of about 38 mu m and then cured to form a light diffusion layer having a diffusion pattern having the shape shown in Fig. To prepare a diffusion sheet including a base substrate and a light diffusion layer. The average thickness of the light-diffusing layer was about 50 mu m.

(4) Production of first and second light converging sheets

0.07 weight% of a catalyst (tetra-n-butylphosphoniumbromide) purchased from Nippon Kogyo Co., Ltd. (Japan) was added to 100 parts by weight of bis (2,3-epithiopropyl) sulfide And the mixture was stirred at room temperature to prepare a homogeneous liquid. The homogeneous liquid was stirred and defoamed and then filtered with a polytetrafluoroethylene membrane (PTFE membrane) having a thickness of about 0.5 탆 to prepare a base material.

The base material was coated on a PET film having a thickness of about 75 탆 and pressurized with a forming roll to produce a light collecting pattern having a height of about 25 탆 on the PET film to prepare a first light collecting sheet.

A second light-converging sheet was prepared in substantially the same manner as the method of producing the first light-converging sheet.

(5) Production of backlight unit

The light guide plate, the diffusion sheet, the first condenser sheet, and the second condenser sheet manufactured in the above-described manner were sequentially laminated, and the light emitting device was assembled to manufacture the backlight unit according to the first embodiment. At this time, the light diffusion layer of the diffusion sheet is arranged to face the light guide plate.

[Example 2]

A backlight unit having substantially the same structure as that of the backlight unit of Example 1 except that a green phosphor LP-F530 (trade name) purchased from LWB (trade name, Germany) as a green phosphor was used for the light emitting element was changed to Example 2 As a backlight unit.

[Example 3]

A backlight unit having substantially the same structure as that of the backlight unit of Example 1 except that a green phosphor ALONBRITE (trade name) purchased from DENKA (trade name, Japan) as a green phosphor was used for the light emitting element, Backlight unit.

[Example 4]

A backlight unit according to Example 4 was manufactured using the light-emitting device, the light guide plate, the first and second light-condensing sheets manufactured in substantially the same manner as described in Example 1 except for the diffusion sheet. Specifically, a light guide plate, a diffusion sheet, a first condensing sheet, and a second condensing sheet were sequentially laminated, and the light emitting device was assembled to fabricate a backlight unit according to Example 4. At this time, And arranged to face the light guide plate.

As the diffusion sheet, those prepared by the following method were used.

20 mg of a wax-based compound (trade name: Licowax PED 136 wax, Clariant, Switzerland) consisting of oxidized HDPE wax having an acid value of about 30 mg KOH / g was added to 1 ml of toluene After mixing, the wax-based compound was dissolved by raising the temperature to about 120 ° C to prepare a wax solution. A solution prepared by dispersing about 20 mg of a red nano light-emitting material (trade name: Nanodot-HE-610, QD solution, Korea) in 1 ml of toluene was added to the wax solution, and the mixture was cooled to room temperature, A dispersion solution in which luminescent particles containing the red nano-luminescent material were dispersed was prepared. The dispersion solution was mixed with urethane acrylate purchased from BASF (Germany) and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) purchased from BASF. The photoinitiator was mixed with about 0.8 part by weight based on 100 parts by weight of urethane acrylate. Then, toluene was removed using an evaporator to prepare a coating composition in which urethane acrylate, luminescent particles and photoinitiator were mixed.

The coating composition was coated on a transparent base substrate (trade name: XU42, Doreya, Japan) having a thickness of about 38 mu m and then cured to form a light diffusion layer having the shape shown in Fig. A diffusion sheet including a substrate and a light-diffusing layer was produced. The average thickness of the light-diffusing layer was about 50 mu m.

[Example 5]

A backlight unit having substantially the same structure as that of the backlight unit of Example 4 except that the green phosphor LP-F530 (trade name) purchased from LWB (trade name, Germany) as the green phosphor was used for the light emitting element was changed to Example 5 As a backlight unit.

[Example 6]

A backlight unit having substantially the same structure as that of the backlight unit of Example 4, except that a green phosphor ALONBRITE (trade name) purchased from DENKA (trade name, Japan) as a green phosphor was used for the light emitting element, Backlight unit.

[Example 7]

A backlight unit according to Example 7 was fabricated using a light guide plate, a diffusion sheet, and first and second condenser sheets manufactured in substantially the same manner as described in Example 1 except for the light emitting element. Specifically, a light guide plate, a diffusion sheet, a first condensing sheet and a second condensing sheet were sequentially laminated, and the light emitting device was assembled to fabricate a backlight unit according to Example 7. At this time, And arranged to face the light guide plate.

As the light emitting element, those prepared by the following method were used.

First, 20 mg of a wax-based compound (trade name: Licowax PED 136 wax, Clariant, Switzerland) consisting of oxidized HDPE wax having an acid value of about 30 mg KOH / g was added to 1 ml of toluene After mixing, the wax-based compound was dissolved by raising the temperature to about 120 ° C to prepare a wax solution. To the wax solution was added a toluene solution containing 20 mg of a green fluorescent substance LP-F525 (trade name) purchased from LWB (trade name, Germany) and mixed with 1 ml of toluene, and the mixture was cooled to room temperature to obtain wax particles A dispersion solution in which a fluorescent complex containing a green phosphor was dispersed was prepared.

A mixture of the fluorescent composite prepared as described above and the A (light emitting layer) of OE-6630 (trade name) purchased from Dow Corning Incorporated (USA) on a blue light emitting chip having an emission peak at about 444 nm purchased from Nichia kit and B kit were mixed at a ratio of 1: 4, and the mixture was cured at 150 ° C for 2 hours to prepare a light emitting device.

[Example 8]

A backlight unit having substantially the same configuration as the backlight unit of Example 7, except that a green phosphor LP-F530 (trade name) purchased from LWB (company name, Germany) was used as a green phosphor for producing a fluorescent composite in a light- A unit was prepared as a backlight unit according to Example 8.

[Example 9]

A backlight unit having substantially the same configuration as that of the backlight unit of Example 7, except that the green phosphor ALONBRITE (trade name) purchased from DENKA Co., Ltd. (trade name) was used as the green phosphor for producing the fluorescent composite in the light emitting element Lt; / RTI > was prepared as a backlight unit according to Example 9.

[Example 10]

The light guide plate, the diffusion sheet, and the first and second light converging sheets manufactured by substantially the same method as that applied to the backlight unit of Example 4 and the light emitting device manufactured by substantially the same method as that applied to the backlight unit of Example 7 A backlight unit according to Example 10 was produced. Specifically, a light guide plate, a diffusion sheet, a first condensing sheet, and a second condensing sheet were sequentially stacked, and the light emitting device was assembled to fabricate a backlight unit according to Example 10. At this time, And arranged to face the light guide plate.

[Example 11]

A backlight unit having substantially the same configuration as the backlight unit of the tenth embodiment except that the green phosphor LP-F530 (trade name) purchased from LWB (company name, Germany) was used as a green phosphor for producing a fluorescent composite in the light emitting element A unit was prepared as a backlight unit according to Example 11.

[Example 12]

A backlight unit having substantially the same structure as the backlight unit of Example 10 except that a green phosphor ALONBRITE (trade name) purchased from DENKA Co., Ltd. (trade name) was used as a green phosphor for producing a fluorescent composite in the light emitting element Was prepared as a backlight unit according to Example 12.

[Comparative Example 1]

A backlight unit according to Comparative Example 1 was manufactured using a light guide plate, a diffusion sheet, and first and second light condensing sheets manufactured by substantially the same method as that applied to the backlight unit of Example 1, except for the light emitting element and the diffusion sheet Respectively. Specifically, a light guide plate, a diffusion sheet, a first condensing sheet and a second condensing sheet were sequentially laminated, and the light emitting device was assembled to fabricate a backlight unit according to Comparative Example 1. At this time, And arranged to face the light guide plate.

As the light emitting element, those prepared by the following method were used.

A YAG phosphor (YAG Phosphor) (available from Nichia Corp., Japan) and Dow Corning Co. (company name, USA) were placed on a blue light emitting chip having an emission peak at about 444 nm purchased from Nichia Corp. A mixture of thermosetting silicone resin mixed with 1: 4 ratio of A kit and B kit of purchased OE-6630 (trade name) was molded and cured at 150 캜 for 2 hours to prepare a light emitting device.

As the diffusion sheet, one prepared by the following method was used.

The coating composition was prepared by mixing urethane acrylate purchased from BASF (Germany) and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) purchased from BASF. The photoinitiator was mixed with about 0.8 part by weight based on 100 parts by weight of urethane acrylate. The coating composition was coated on a transparent base substrate (trade name: XU42, Doreya, Japan) having a thickness of about 38 mu m and then cured to form a light diffusion layer having the shape shown in Fig. A diffusion sheet including a substrate and a light diffusion layer was prepared, and the average thickness of the light diffusion layer was about 50 탆.

Hereinafter, effects of the present invention will be described through the evaluation of the color coordinates and the color reproduction area of the display device including the backlight unit according to the embodiments and the comparative example.

[Experiment 3] Evaluation of color coordinates and color reproduction area of display device

Each of the backlight units according to Examples 1 to 12 and Comparative Example 1 was assembled with a display panel of an iPhone 4 (trade name, Apple Inc., USA) to produce Display Devices 1 to 12 and Comparative Device 1.

The display apparatuses 1 to 12 and the comparative apparatus 1 were each provided with a color reproduction area (Color Gamut), luminance and color coordinates (red, green and blue) using a spectroradiometer SR-3AR (trade name, TOPCON, Were measured. The color coordinates of the red, green and blue colors were obtained by causing the display panel of the iPhone 4 to display red, green and blue, respectively, and then recording the color coordinates indicated by the spectral photocopier. The results are shown in Table 3 below.

In Table 3, the red, green, and blue color coordinates are shown based on the CIE 1931 color coordinate system, and the gamut ratios are represented by the respective display devices for the gamut range (hereinafter referred to as NTSC gamut range) based on the National Television Systems Committee (NTSC) The RGB color coordinates in the triangle are expressed as a percentage of the area of the triangle.

division Color gamut ratio (%) Luminance
(cd / m ² ) Color Coordinates - Red
(CIE 1931) Color coordinates - Green
(CIE 1931) Color coordinates - blue
(CIE 1931) Display device 1 (LP-F525) 76.5 295 (0.665, 0.323) (0.267, 0.645) (0.160, 0.123) Display device 2 (LP-F530) 70.6 310 (0.665, 0.323) (0.315, 0.627) (0.160, 0.123) Display device 3 (ALONBRITE) 66.9 303 (0.665, 0.323) (0.369, 0.611) (0.160, 0.123) Display device 4 (LP-F525) 75.8 300 (0.660, 0.319) (0.267, 0.645) (0.160, 0.123) Display device 5 (LP-F530) 70.0 314 (0.660, 0.319) (0.315, 0.627) (0.160, 0.123) Display device 6 (ALONBRITE) 64.1 309 (0.660, 0.319) (0.369, 0.611) (0.160, 0.123) Display device 7 (LP-F525) 77.3 303 (0.665, 0.323) (0.262, 0.648) (0.160, 0.123) Display device 8 (LP-F530) 71.3 318 (0.665, 0.323) (0.311, 0.630) (0.160, 0.123) Display 9 (ALONBRITE) 65.4 312 (0.665, 0.323) (0.366, 0.615) (0.160, 0.123) Display device 10 (LP-F525) 76.6 317 (0.660, 0.319) (0.262, 0.648) (0.160, 0.123) Display device 11 (LP-F530) 70.7 329 (0.660, 0.319) (0.311, 0.630) (0.160, 0.123) Display device 12 (ALONBRITE) 64.9 322 (0.660, 0.319) (0.366, 0.615) (0.160, 0.123) Comparison device 1 51.3 314 (0.611, 0.354) (0.318, 0.564) (0.160, 0.123)

Referring to Table 3, it can be seen that the red color coordinates of the display devices 1 to 12 have a relatively larger X-coordinate value and a relatively smaller Y-coordinate value than the red color coordinate of the comparison device 1. It can also be seen that the green color coordinates of the display devices 1 to 12 have a Y-coordinate value relatively larger than the green color coordinate of the comparison device 1. [ That is, it can be seen that the display devices 1 to 12 can realize red and green colors having higher color purity than the comparative device 1.

Further, it can be seen that the display devices 1 to 12 have a significantly increased gamut ratio value as compared with the comparison device 1. It can be inferred that the display devices 1 to 12 can realize red and green colors having relatively higher color purity than the comparative device 1.

Furthermore, it can be confirmed that the display apparatuses 1 to 12 have substantially the same or improved luminance value as the comparison apparatus 1. That is, even when luminescent particles in which a red nano emitter or a red nano emitter is encapsulated with a wax-based compound are dispersed in the diffusion sheet, the brightness of the display device does not largely change.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims. It can be understood that it is possible.

1000, 1001, 1002: backlight unit
1100, 1102: Light emitting element
1200: light guide plate
1300: Reflector
1400, 1402, 1403, 1404, 1405, 1406: diffusion sheet
1500, 1501, 1502: first condensing sheet
1600: second condensing sheet
1503: condensing sheet
1132: green phosphor
CX, 100a, 100b, 100c, 200a, 200b, 200c:
20, 120, 220: red nano luminescent material
110, 210, 1133: Wax particles
1134: Fluorescent complex

Claims (7)

A blue light emitting chip emitting blue light; And
Wherein the fluorescent composite is disposed on the blue light emitting chip and includes a wax-based compound-recrystallized wax particle and a green phosphor disposed inside the wax particle and emitting green light, the light- device.
The light emitting device according to claim 1, wherein the emission spectrum of the green light emitted by the fluorescent composite has a half width of 80 nm or less.
The green phosphor according to claim 1,
A silicate-based fluorescent material, a silicon oxynitride-based fluorescent material, a sulfide-based fluorescent material, a sialon-based fluorescent material, and an oxide-based fluorescent material.
The wax according to claim 1,
Based wax, a polypropylene-based wax, or an amide-based wax. The light-emitting device of claim 1,
The wax according to claim 1,
And an acid value of 1 mg KOH / g to 200 mg KOH / g.
The wax according to claim 1,
And a wax-based compound having a density of 0.95 g / cm ³ or more.
The wax according to claim 1,
A light-emitting element formed of a wax-based compound comprising at least one of the following units represented by the following formulas (1) to (7);
[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

(7)

R ₁ , R ₃ , R ₅ and R ₇ are each independently a single bond or an alkylene group having 1 to 10 carbon atoms (* - (CH 2) _x - *, _x may be an integer from 1 to _{10), R 2, R 4} , R 6 and R ₈ may be a group having the hydrogen or carbon number of 1 to 10, each independently, R _a, R _b, R _c , R _d , R _e , R _f and R _g each independently represent hydrogen or an alkyl group having 1 to 3 carbon atoms.

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