KR101854779B1 - Optical member and display device having the same - Google Patents

Abstract

An optical member and a display device including the same are disclosed. The optical member includes a host layer; A plurality of first wavelength conversion particles disposed in the host layer; And a plurality of second wavelength conversion particles disposed in the host layer, wherein the first wavelength conversion particles include a compound semiconductor, and the second wavelength conversion particles include a phosphor.

Description

TECHNICAL FIELD [0001] The present invention relates to an optical member and a display device including the optical member.

An embodiment relates to an optical member and a display device including the optical member.

Among display devices, there is a device that requires a backlight unit capable of generating light in order to display an image. The backlight unit is a device for supplying light to a display panel including a liquid crystal or the like and includes a light emitting device and means for effectively transmitting the light output from the light emitting device to the liquid crystal side.

As a light source of such a display device, an LED (Light Emitted Diode) or the like can be applied. Further, in order that the light output from the light source is effectively transmitted to the display panel side, a light guide plate and an optical sheet may be laminated and used.

At this time, an optical member that changes the wavelength of light generated from the light source and causes white light to enter the light guide plate or the display panel can be applied to such a display device. Particularly, in order to change the wavelength of light, a quantum dot or the like can be used.

The quantum dot has a particle size of 10 nm or less and has unique electrical and optical characteristics depending on its size. For example, when the approximate size is 55 to 65 Å, it can emit red, 40 to 50 Å to green, and 20 to 35 Å to blue. Yellow has medium size of red and green quantum dots. As the spectrum of light changes from red to blue, the size of the quantum dots varies from 65 Å to 20 Å, which may be slightly different.

In order to form the optical member including the quantum dots, the quantum dots emitting RGB or RYGB, which are three primary colors of light, can be formed by spin coating or printing on a transparent substrate such as glass. Here, when a quantum dot emitting yellow (Y) is further included, white light closer to natural light can be obtained. The matrix (medium) in which the quantum dots are dispersed can apply an inorganic substance or a polymer having excellent transmittance with respect to light in the visible light region and the ultraviolet region (including Far UV) or in the visible light region. For example, it may be inorganic silica, polymethylmethacrylate (PMMA), polydimethylsiloxane (PDMS), poly lactic acid (PLA), silicon polymer or YAG.

A display device to which such a quantum dot is applied is disclosed in Korean Patent Laid-Open Publication No. 10-2011-0012246.

The embodiment intends to provide an optical member and a display device having improved luminance and color reproduction ratio.

An optical member according to an embodiment includes a host layer; A plurality of first wavelength conversion particles disposed in the host layer; And a plurality of second wavelength conversion particles disposed in the host layer, wherein the first wavelength conversion particles include a compound semiconductor, and the second wavelength conversion particles include a phosphor.

A display device according to an embodiment includes a light source; A wavelength conversion member into which light emitted from the light source is incident; And a display panel on which light emitted from the wavelength conversion member is incident, wherein the wavelength conversion member comprises: a host layer; A plurality of first wavelength conversion particles disposed in the host layer; And a plurality of second wavelength conversion particles disposed in the host layer, wherein the first wavelength conversion particles include a compound semiconductor, and the second wavelength conversion particles include a phosphor.

The optical member according to the embodiment includes the first wavelength conversion particles and the second wavelength conversion particles in one host layer. In particular, the first wavelength conversion particles may be a quantum dot, and the second wavelength conversion particles may include a phosphor. The first wavelength-converted particles convert incident light into light of a first wavelength band, and the second wavelength-converted particles convert incident light into light of a second wavelength band.

Particularly, the first wavelength conversion particles convert incident light into green light, and the second wavelength conversion particles convert incident light into red light.

Further, in order to form the optical member according to the embodiment, the fluorescent substance is added first, and the dispersion improving particles may be used. Accordingly, the phosphor that is resistant to mechanical impact is dispersed first, and the dispersibility improving particles can prevent the phosphor from aggregating. Therefore, the manufacturing method of the optical member according to the embodiment can easily disperse the phosphor, the quantum dot, and the like.

Therefore, the optical member according to the embodiment can have improved luminance and color reproducibility.

In addition, the first wavelength converting particles may include a protective film or may include a compound of two or more Group II elements. Accordingly, the first wavelength conversion particles can have improved reliability.

1 is an exploded perspective view showing a liquid crystal display device according to a first embodiment.
2 is a perspective view showing the wavelength conversion member according to the first embodiment.
FIG. 3 is a cross-sectional view showing a section cut along AA 'in FIG. 2. FIG.
4 is a cross-sectional view showing the first wavelength conversion particle.
5 is a cross-sectional view showing another type of first wavelength conversion particle.
6 is a graph showing the composition of cadmium in the first wavelength conversion particles.
FIGS. 7 and 8 are views showing a process of manufacturing the wavelength converting member according to the first embodiment.
9 is a cross-sectional view showing the wavelength conversion member according to the second embodiment.
10 is a graph showing the intensity versus intensity of white light generated by the wavelength converting member according to the second embodiment.
11 is an exploded perspective view showing a liquid crystal display device according to a third embodiment.
12 is a perspective view showing the wavelength conversion member according to the third embodiment.
FIG. 13 is a cross-sectional view showing a section cut along BB 'in FIG. 12; FIG.
FIG. 14 is a cross-sectional view showing one end surface of a light guide plate, a light emitting diode, and a wavelength conversion member according to the third embodiment.
15 to 17 are views illustrating a process of forming the wavelength converting member according to the third embodiment.
18 is an exploded perspective view showing a liquid crystal display device according to the fourth embodiment.
19 is a perspective view showing the wavelength conversion member according to the fourth embodiment.
20 is a cross-sectional view showing a cross section cut along CC 'in FIG.
FIG. 21 is a cross-sectional view illustrating one side of a light guide plate, a light emitting diode, and a wavelength conversion member according to the fourth embodiment.

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

1 is an exploded perspective view showing a liquid crystal display device according to a first embodiment. 2 is a perspective view showing the wavelength conversion member according to the first embodiment. 3 is a cross-sectional view showing a section taken along line A-A in Fig. 4 is a cross-sectional view showing the first wavelength conversion particle. 5 is a cross-sectional view showing another type of first wavelength conversion particle. 6 is a graph showing the composition of cadmium in the first wavelength conversion particles. FIGS. 7 and 8 are views showing a process of manufacturing the wavelength converting member according to the first embodiment.

1 to 6, a liquid crystal display according to an embodiment includes a backlight unit 10 and a liquid crystal panel 20.

The backlight unit 10 emits light to the liquid crystal panel 20. The backlight unit 10 is a surface light source and can uniformly irradiate the bottom surface of the liquid crystal panel 20 with light.

The backlight unit 10 is disposed under the liquid crystal panel 20. The backlight unit 10 includes a bottom cover 100, a light guide plate 200, a reflective sheet 300, a light source such as a plurality of light emitting diodes 400, a printed circuit board 401, (500).

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

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

The reflective sheet 300 is disposed under the light guide plate 200. More specifically, the reflective sheet 300 is disposed between the light guide plate 200 and the bottom surface of the bottom cover 100. The reflective sheet 300 reflects light emitted from the lower surface of the light guide plate 200 upward.

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

The light emitting diodes 400 may be a blue light emitting diode for generating blue light or a UV light emitting diode for generating ultraviolet light. That is, the light emitting diodes 400 may emit blue light having a wavelength range of about 430 nm to about 470 nm or ultraviolet light having a wavelength band of about 300 nm to about 400 nm.

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

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

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

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

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

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

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

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

2 and 3, the wavelength conversion member 501 includes a lower substrate 510, an upper substrate 520, a wavelength conversion layer 530, and a sealing portion 540.

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

Examples of the material used for the lower substrate 510 include transparent polymers such as polyethylene terephthalate (PET) and the like.

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

Examples of materials used for the upper substrate 520 include transparent polymers such as polyethylene terephthalate.

The lower substrate 510 and the upper substrate 520 sandwich the wavelength conversion layer 530. The lower substrate 510 and the upper substrate 520 support the wavelength conversion layer 530. The lower substrate 510 and the upper substrate 520 protect the wavelength conversion layer 530 from external physical impacts. The lower substrate 510 and the upper substrate 520 may be in direct contact with the wavelength conversion layer 530.

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

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

The wavelength conversion layer 530 includes a host layer 531, a plurality of first wavelength conversion particles 532, a plurality of second wavelength conversion particles 533, and a plurality of dispersion enhancing particles 535 do.

The host layer 531 surrounds the first wavelength-converted particles 532, the second wavelength-converted particles 533, and the dispersion enhancing particles 535. That is, the host layer 531 uniformly disperses the first wavelength-converted particles 532, the second wavelength-converted particles, and the dispersion improving particles 535 therein. The host layer 531 may be made of a polymer such as a silicone resin. The host layer 531 is transparent. That is, the host layer 531 may be formed of a transparent polymer.

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

The first wavelength conversion particles 532 are disposed between the lower substrate 510 and the upper substrate 520. More specifically, the first wavelength-converted particles 532 are uniformly dispersed in the host layer 531, and the host layer 531 is disposed between the lower substrate 510 and the upper substrate 520 . The first wavelength converting particles may be dispersed in the host at a concentration of about 0.5 wt% to about 5 wt%.

The first wavelength converting particles 532 convert the wavelength of the light emitted from the light emitting diodes 400. The first wavelength conversion particles 532 receive light emitted from the light emitting diodes 400 and convert wavelengths. For example, the first wavelength conversion particles 532 may convert light emitted from the light emitting diodes 400 into green light. That is, the first wavelength-converted particles 532 can convert the incident light into green light having a wavelength range of about 500 nm to about 600 nm.

The first wavelength conversion particles include a compound semiconductor. More specifically, the first wavelength conversion particles may be nanoparticles containing compound semiconductors. More specifically, the first wavelength converting particles 532 may be a quantum dot (QD). The quantum dot may include core nanocrystals and shell nanocrystals surrounding the core nanocrystals. In addition, the quantum dot may include an organic ligand bound to the shell nanocrystal. In addition, the quantum dot may include an organic coating layer surrounding the shell nanocrystals.

The shell nanocrystals may be formed of two or more layers. The shell nanocrystals are formed on the surface of the core nanocrystals. The quantum dot may convert the wavelength of the light incident on the core core crystal into a long wavelength through the shell nanocrystals forming the shell layer and increase the light efficiency.

The quantum dot may include at least one of a group II compound semiconductor, a group III compound semiconductor, a group V compound semiconductor, and a group VI compound semiconductor. More specifically, the core nanocrystals may include Cdse, InGaP, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe or HgS. The shell nanocrystals may include CuZnS, CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe or HgS. The diameter of the quantum dot may be 1 nm to 50 nm.

The wavelength of the light emitted from the quantum dot can be adjusted according to the size of the quantum dot. The organic ligand may include pyridine, mercapto alcohol, thiol, phosphine, phosphine oxide, and the like. The organic ligands serve to stabilize unstable quantum dots after synthesis. After synthesis, a dangling bond is formed on the outer periphery, and the quantum dots may become unstable due to the dangling bonds. However, one end of the organic ligand is in an unbonded state, and one end of the unbound organic ligand bonds with the dangling bond, thereby stabilizing the quantum dot.

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

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

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

More specifically, a quantum dot that converts blue light into green light by the first wavelength-converted particles 532 may be used.

More specifically, the first wavelength conversion particles 532 include a compound semiconductor including a first metal element and a second metal element. At this time, the first metal element and the second metal element may be a group II element. That is, the first metal element may be a first group II element, and the second metal element may be a second group II element different from the first group II element. Further, the compound semiconductor includes two or more kinds of metal elements. That is, the compound semiconductor may also include a third metal element. The compound semiconductor may include more kinds of metal elements.

Further, the compound semiconductor may include a group VI element. That is, the compound semiconductor may be a group II-VI compound semiconductor. More specifically, the compound semiconductor may include a first VI group element and a second VI group element different from the first VI group element.

The first metal element and the second metal element may be selected from metals such as Cd, Zn, Pb or Hg. However, it is not limited thereto. In addition, the first VI group element and the second VI group element may be selected from S, Se or Te.

The compound semiconductor may be represented by the following chemical formula (1).

Formula 1

A _X B _{1 - X} C _Y D _{1 - Y}

Where A is a Group II element, B is a Group II element other than A, C is a Group VI element, D is another Group VI element other than C, 0 <X <1 and 0 <Y <1. More specifically, A may be cadmium and B may be zinc.

More specifically, the first metal element may be cadmium, the second metal element may be zinc, the first group VI element may be selenium, and the second group VI element may be sulfur. That is, the compound semiconductor may be a CdZnSeS compound semiconductor.

As shown in FIG. 4, the first wavelength converting particles 532 may have a single particle structure. That is, the first wavelength conversion particles 532 may be a single structure particle, not a multi-layer structure. That is, the first wavelength-converted particles 532 may be formed of the compound semiconductor as a whole.

5, the first wavelength-converted particles 532 may include nanoparticles 532a and a protective layer 532b around the nanoparticles 532a. The protective film 532b surrounds the nanoparticles 532a. The protective layer 532b is deposited on the outer surface of the nanoparticles 532a. That is, the protective layer 532b may be deposited on the outer surface of the nanoparticles 532a. That is, the protective layer 532b is disposed directly on the outer surface of the nanoparticles 532a. The protective layer 532b is coated on the outer surface of the nanoparticles 532a. The protective layer 532b may be entirely coated on the outer surface of the nanoparticles 532a.

Accordingly, the nanoparticle 532a complex can be formed by the nanoparticles 532a and the protective film 532b. That is, the nanoparticle (532a) composite may have a core / shell structure.

The protective layer 532b may include a Group II-VI-based compound. For example, the protective layer 532b may include CuZnS, CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe, or HgS.

The protective layer 532b may include a metal oxide. More specifically, the protective film 532b may be formed of a metal oxide. The metal oxide may be an oxide of the first metal element or the second metal element. Further, the metal oxide may be an oxide of a Group II element. For example, the metal oxide may be cadmium oxide or zinc oxide.

The metal oxide may be an oxide of a metal other than the first metal element and the second metal element. For example, the metal oxide may be selected from tin oxide, aluminum oxide or titanium oxide.

The protective film 532b may be formed by vapor deposition. In order for the protective film 532b to be formed, the nanoparticles 532a are uniformly dispersed in the solvent. The solvent may be an organic solvent or a solvent. Examples of the solvent include 1-octadecene, toluene, trioctylphosphine oxide, and the like.

Then, an organic metal compound for forming the protective film 532b is added to a solvent in which the nanoparticles 532a are dispersed. The organometallic compound is a source of the metal oxide used as the protective film 532b. The amount of the organic metal compound to be added can be variously controlled depending on the amount of nanoparticles 532a mixed in the solvent and the thickness of the protective film 532b to be formed.

The organometallic compound may have a structure in which a metal is directly bonded to oxygen. More specifically, the organometallic compound may be a carboxylate or an alkoxide. That is, the organometallic compound may be a metal salt of a carboxylic acid or a metal salt of an alcohol.

For example, the organometallic compound may be a metal complex of acetic acid, oleic acid, stearic acid, myristic acid, or lauric acid . At this time, the metal included in the organometallic compound may be a Group II element. Examples of the metal contained in the organic metal compound include aluminum, tin, and titanium.

The content of the first metal element and the content of the second metal element may vary depending on the position of the first wavelength converting particles 532. [ That is, the composition of the compound semiconductor may be varied depending on the position of the first wavelength-converted particles 532. More specifically, the nanoparticles 532a include the first metal element and the second metal element as a whole, and the composition of the first metal element and the composition of the second metal 532a, The composition of the element may be changed.

For example, the content of the first metal element may become smaller as the nanoparticle 532a moves from the center to the outer periphery thereof. In addition, the content of the second metal element may be gradually increased from the center of the nanoparticle 532a to the outer periphery thereof.

For example, in the above Formula 1, as the nanoparticles 532a move from the center to the outer periphery, X may become smaller and smaller.

More specifically, when the first metal element is cadmium, as shown in FIG. 6, the composition of the cadmium can be gradually decreased from the center to the outer periphery.

That is, when the compound semiconductor is a CdZnSeS compound semiconductor, the composition of cadmium is much higher than that of zinc at the central portion of the nanoparticle 532a, and the composition of cadmium at the outer portion is much lower than that of zinc . Further, depending on the distance from the center of the nanoparticles 532a, the composition of the cadmium can be reduced non-linearly. In particular, the composition of cadmium may be reduced to have two or more inflection points as the distance from the center of the nanoparticles 532a increases.

In order to form the first WTR 532, two or more metal precursors and one or more Group VI precursors in a solvent are added and mixed.

The solvent may be an organic solvent such as 1-octadecene, toluene or trioctylphosphine oxide, but is not limited thereto.

The metal precursors may be a first metal precursor and a second metal precursor. More specifically, the metal precursors may be Group II metal precursors. Examples of the metal precursors may be alkylcarboxylic acid metal complex materials. For example, the metal precursors may be metal complexes of oleic acid, stearic acid, myristic acid or lauric acid. In particular, the metal precursors may be cadmium (Cd) or zinc (Zn) complexes of the alkylcarboxylic acid. The metal precursors may also be hydroxides of metals. For example, examples of the metal precursors include Cd (OH) ₂ , CdO, Zn (OH) ₂ , and ZnO.

The first metal precursor may comprise cadmium and the second metal precursor may comprise zinc. For example, the first metal precursor may be a cadmium (Cd) complex of the alkylcarboxylic acid, cadmium hydroxide (Cd (OH) ₂ ) or cadmium oxide (CdO). Alternatively, the second metal precursor may be a zinc complex compound of the alkylcarboxylic acid, zinc hydroxide (Zn (OH) ₂ ), or zinc oxide (ZnO).

The Group VI precursors may be compounds of Group VI elements. More precisely, the Group VI element precursors may be compounds of selenium (Se), sulfur (S) or tellurium (Te). More specifically, examples of the Group VI element precursors include trioctylphosphine selenium (TOPSe), trioctylphosphinic sulfur (TOPS), trioctylphosphine ternary (TOPTe), tributylphosphine selenium (TBPSe), tributylphosphinic (TPPS), triisopropylphosphine (TPPS), triisopropylphosphonium (TPPS), and the like can be mentioned. However, It is not.

Further, a surfactant may be further added to the reaction solution.

Further, the reaction solution may further include a nucleophilic catalyst. The nucleophilic catalyst can control the reaction rate in the reaction solution. As the nucleophilic catalyst, amine or phosphine may be used. More specifically, examples of the substance used as the nucleophilic catalyst include alkylamines or alkylphosphines. More specifically, examples of the substance used as the nucleophilic catalyst include hexylamine, octylamine, dihexylamine, dioctylamine, oleylamine, dioctylphosphine dioctylphosphine, trioctylphosphine or water.

Thereafter, the reaction solution is heated. The heating rate of the reaction solution may be about 20 [deg.] C / min to about 30 [deg.] C / min. Further, the reaction solution may be heated at a room temperature to a temperature of about 50 캜 to about 400 캜. More specifically, the reaction solution may be heated to a temperature of about 180 ° C to about 310 ° C.

Also, the reaction solution may be elevated to a temperature of about 190 &lt; 0 &gt; C to about 210 &lt; 0 &gt; C. Also, the reaction solution may be raised to a temperature of about 220 &lt; 0 &gt; C to about 230 &lt; 0 &gt; C. Further, the reaction solution may be elevated to a temperature of about 245 ° C to about 255 ° C. The reaction solution may be raised to a temperature of about 270 &lt; 0 &gt; C to about 280 &lt; 0 &gt; C. The reaction solution may be raised to a temperature of about 290 ° C to about 310 ° C.

Further, the reaction solution may be maintained at a temperature for about 1 minute to about 15 minutes after being raised to a predetermined temperature.

Accordingly, the first wavelength conversion particles 532 are formed. At this time, a compound semiconductor including a first metal element included in the first metal precursor and a second metal element included in the second metal precursor is formed.

Particularly, when the first metal precursor is a cadmium compound and the second metal precursor is a zinc compound, the reaction rate constant of cadmium is much larger. Accordingly, since cadmium mainly reacts with sulfur and / or selenium at the beginning of the reaction, the content of cadmium in the center portion of the nanoparticles 532a becomes very high. Also, as cadmium reacts, the concentration of the cadmium compound may be lowered and the reaction rate of cadmium may be decreased. Accordingly, the composition of the cadmium is lowered toward the periphery of the nanoparticles 532a, and the content of zinc is increased.

Thereafter, the reaction solution can be cooled. The reaction solution can be rapidly cooled to room temperature. For example, the reaction solution may be cooled at a rate of about 100 ° C / minute.

The first wavelength conversion particles 532 include compound semiconductors including two or more kinds of metal elements. Accordingly, the first wavelength conversion particles 532 can appropriately adjust the band gap energy according to the composition of each metal element. That is, the first wavelength conversion particles 532 are not limited to the diameter, but can freely adjust the band gap energy. Accordingly, the first wavelength-converted particles 532 can generate light having a large diameter and a long wavelength band.

For example, the first wavelength converting particles 532 may have a diameter of about 2 nm to about 8 nm, and may have a wavelength of about 500 nm to about 600 nm incident light having a wavelength of about 300 nm to about 400 nm Can be converted into light.

More specifically, the first wavelength converting particles 532 have a diameter of about 2 nm to about 3 nm, and incident light having a wavelength of about 300 nm to about 400 nm is incident on the first wavelength converting particles 532 having a wavelength of about 500 nm to about 510 nm It can be converted into light.

More specifically, the first wavelength converting particles 532 have a diameter of from about 3 nm to about 4 nm, incident light having a wavelength of from about 300 nm to about 400 nm at a wavelength of from about 520 nm to about 530 nm It can be converted into light.

More specifically, the first wavelength converting particles 532 have a diameter of about 3.5 nm to about 4.5 nm, and incident light having a wavelength of about 300 nm to about 400 nm is incident on the first wavelength converting particles 532 having a wavelength of about 540 nm to about 550 nm It can be converted into light.

More specifically, the first wavelength-converted particles 532 have a diameter of about 4.5 nm to about 5.5 nm, and incident light having a wavelength of about 300 nm to about 400 nm is incident on the first wavelength-converted particles 532 having a wavelength of about 555 nm to about 565 nm It can be converted into light.

More specifically, the first wavelength converting particles 532 have a diameter of from about 5.5 nm to about 6.5 nm, and incident light having a wavelength of from about 300 nm to about 400 nm is emitted at a wavelength of about 570 nm to about 580 nm It can be converted into light.

More specifically, the first wavelength converting particles 532 have a diameter of from about 6.5 nm to about 7.5 nm, and incident light having a wavelength of from about 300 nm to about 400 nm is emitted at a wavelength of about 580 nm to about 590 nm It can be converted into light.

In addition, the first wavelength-converted particles 532 have a higher composition of the metal element having higher reactivity as it is closer to the center, and a lower-reactive metal element as the closer to the outer periphery thereof. Accordingly, the first wavelength-converted particles 532 may have high stability. That is, the first wavelength conversion particles 532 may have a single particle structure and a high stability.

The second wavelength conversion particles 533 are disposed in the host layer 531. More specifically, the second wavelength conversion particles 533 can be uniformly dispersed in the host layer.

The second wavelength conversion particles 533 may have a larger diameter than the first wavelength conversion particles 532. More specifically, the diameter of the second wavelength conversion particles 533 may be about 1 [mu] m to about 50 [mu] m.

The second wavelength conversion particles 533 convert the wavelength of the light emitted from the light emitting diodes 400. The second wavelength conversion particles 533 receive light emitted from the light emitting diodes 400 and convert wavelengths. For example, the second wavelength conversion particles 533 may convert the light emitted from the light emitting diodes 400 into red light. That is, the second wavelength conversion particles 533 can convert the light into red light having a wavelength range of about 600 nm to about 700 nm.

The second wavelength conversion particles 533 may be a red phosphor. For example, examples of the red phosphors include praseodymium or aluminum-doped strontium titanium oxide phosphors (e.g., SrTiO3: Pr, Al) or praseodymium doped calcium titanate phosphors (e.g., CaTiO3: Pr) And the like.

The dispersion enhancing particles 535 are disposed in the host layer 531. The dispersion enhancing particles 535 may be uniformly dispersed in the host layer 531. The dispersion enhancing particles 535 may be uniformly dispersed between the first wavelength conversion particles 532 and the second wavelength conversion particles 533. [

The dispersibility improving particles 535 may be transparent. The dispersibility improving particles 535 may include an inorganic material. More specifically, examples of the material used as the dispersibility improving particles 535 include oxides such as silicon oxide and the like. For example, silica particles may be used as the dispersion enhancing particles 535.

The diameter of the dispersion enhancing particles 535 may be about 10 nm to about 10 탆. In addition, the dispersion improving particles 535 may be included in the host layer 531 at a ratio of about 0.5 wt% to about 5 wt%.

The dispersion enhancing particles 535 may function to improve dispersibility of the first wavelength conversion particles 532 and the second wavelength conversion particles 533 in the host layer 531 have. In addition, the dispersibility improving particles 535 may function as a scattering particle to change the path of incident light.

The wavelength converting member 501 may be formed by the following process.

Referring to FIG. 7, a plurality of second wavelength conversion particles 533 are uniformly dispersed in a silicone resin, an epoxy resin, an acrylic resin, or the like. At this time, the second wavelength conversion particles 533 may be dispersed by ultrasonic dispersion. That is, ultrasonic waves may be applied to the second wavelength conversion particles, and the second wavelength conversion particles may be pulverized to have a small diameter.

At this time, since the second wavelength conversion particles 533 include phosphors, their performance is not deteriorated even if the second wavelength conversion particles 533 are dispersed violently like the ultrasonic dispersion. That is, in a situation where the first wavelength conversion particles 532 are not included, the second wavelength conversion particles 533 may be dispersed first in a violent manner.

Then, dispersion improving particles 535 are added to the resin composition in which the second wavelength converting particles 533 are dispersed. The dispersibility improving particles 535 may increase the viscosity of the resin composition. Accordingly, the dispersion enhancing particles 535 can prevent the second wavelength conversion particles 533 from coagulating again. That is, the dispersion enhancing particles 535 may function to maintain dispersibility of the second wavelength conversion particles 533.

The dispersion improving particles 535 may be added to the resin composition at a ratio of about 0.5 wt% to about 5 wt%.

Then, the first wavelength conversion particles 532 are added to the resin composition. The first wavelength conversion particles 532 may be dispersed in the resin composition by a method less intense than the second wavelength conversion particles 532. [

Referring to FIG. 8, the resin composition is uniformly coated on the lower substrate 510. The resin composition may be coated on the upper surface of the lower substrate 510 by slit coating, spin coating, spray coating, or the like.

Thereafter, after the second wavelength conversion particles 533 are precipitated, the coated resin composition is cured by light and / or heat, and a wavelength conversion layer is formed.

Then, the upper substrate 520 is laminated on the wavelength conversion layer 530, and a sealing portion is formed. Accordingly, the wavelength converting member 501 can be formed.

The sealing portion 540 is disposed on the side of the wavelength conversion layer 530. More specifically, the sealing portion 540 covers the side surface of the wavelength conversion layer 530. More specifically, the sealing portion 540 is disposed on the side surfaces of the lower substrate 510 and the upper substrate 520. More specifically, the sealing portion 540 covers the side surfaces of the lower substrate 510 and the upper substrate 520.

The sealing portion 540 may be adhered to the side surfaces of the wavelength conversion layer 530, the lower substrate 510, and the upper substrate 520. The sealing portion 540 is in close contact with the side surfaces of the wavelength conversion layer 530, the lower substrate 510, and the upper substrate 520.

Accordingly, the sealing portion 540 can seal the side surface of the wavelength conversion layer 530. That is, the sealing portion 540 protects the wavelength conversion layer 530 from external chemical impact.

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

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

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

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

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

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

A driving PCB 25 for supplying a driving signal to the gate line and the data line is provided at the edge of the liquid crystal panel 20.

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

As described above, the first wavelength-converted particles 532 and the second wavelength-converted particles 533 are included in one host layer 531. In particular, the first wavelength conversion particles 532 may be a quantum dot, and the second wavelength conversion particles 533 may include a phosphor. In addition, the first wavelength conversion particles 532 convert incident light into light of a first wavelength band, and the second wavelength conversion particles 533 convert incident light into light of a second wavelength band.

Further, in order to form the wavelength converting member 501, the fluorescent substance is added first, and the dispersion improving particles 535 may be used. Accordingly, the phosphor that is resistant to mechanical impact is dispersed first, and the dispersibility improving particles 535 can prevent aggregation of the phosphor. Therefore, the method of manufacturing the wavelength converting member 501 can easily disperse the fluorescent material, the quantum dot, and the like.

Therefore, the liquid crystal display according to the embodiment can have improved luminance and color reproducibility.

9 is a cross-sectional view showing the wavelength conversion member according to the second embodiment. In the description of this embodiment, the description of the foregoing embodiment will be made. That is, the description of the above-described liquid crystal display device can be essentially combined with the description of the present liquid crystal display device except for the changed portions.

Referring to FIG. 9, the wavelength conversion member according to the present embodiment includes third wavelength conversion particles 534. The third wavelength conversion particles 534 are disposed in the host layer 531. More specifically, the third wavelength conversion particles 534 may be uniformly dispersed in the host layer 531. [

The third wavelength conversion particles 534 may be included in the host layer 531 at a concentration of about 0.1 wt% to about 0.5 wt%.

The third wavelength converting particles 534 may have a diameter larger than that of the first wavelength converting particles 532. More specifically, the diameter of the third wavelength conversion particles 534 may be about 0.5 탆 to about 10 탆.

The third wavelength conversion particles 534 convert the wavelength of the light emitted from the light emitting diodes 400. The third wavelength conversion particles 534 receive the light emitted from the light emitting diodes 400 and convert the wavelength. For example, the third wavelength conversion particles 534 may convert blue light emitted from the light emitting diodes 400 into yellow light. That is, the third wavelength conversion particles 534 may convert the blue light into yellow light having a wavelength range of about 540 nm to about 570 nm.

When the light emitting diodes 400 are blue light emitting diodes for generating blue light, the third wavelength conversion particles 534 for converting the blue light into yellow light may be used.

The third wavelength conversion particles 534 may be a phosphor. As the third wavelength converting particles 534, a yellow phosphor may be used. More specifically, examples of the yellow phosphors include yttrium aluminum garnet (YAG) phosphors.

10, in the white light formed by the wavelength converting member 501 according to the present embodiment, the third wavelength conversion particles 534 are used to convert the wavelength band of about 555 nm to about 560 nm Y) can be increased.

Accordingly, the wavelength converting member 501 according to the present embodiment can generate white light having an improved luminance. Therefore, the display device including the wavelength converting member 501 according to the present embodiment can have improved luminance and color reproducibility.

In addition, the third wavelength conversion particles 534 may be dispersed in the resin composition together with the second wavelength conversion particles 533. That is, in order to form the wavelength converting member 501 according to the present embodiment, after the second wavelength converting particles 533 and the third wavelength converting particles 534 are dispersed first, The particles 532 may be dispersed later.

11 is an exploded perspective view showing a liquid crystal display device according to a third embodiment. 12 is a perspective view showing the wavelength conversion member according to the third embodiment. FIG. 13 is a cross-sectional view showing a section cut along the line B-B 'in FIG. 12; FIG. FIG. 14 is a cross-sectional view showing one end surface of a light guide plate, a light emitting diode, and a wavelength conversion member according to the third embodiment. 15 to 17 are views illustrating a process of forming the wavelength converting member according to the third embodiment. In the description of this embodiment, the description of the foregoing embodiment will be made. That is, the description of the above-described liquid crystal display device can be essentially combined with the description of the present liquid crystal display device except for the changed portions.

11 to 14, the wavelength conversion member 600 is sandwiched between the light emitting diodes 400 and the light guide plate 200.

The wavelength conversion member 600 may have a shape elongated in one direction. More specifically, the wavelength conversion member 600 may have a shape extending along one side of the light guide plate 200. More specifically, the wavelength conversion member 600 may have a shape extending along the incident surface of the light guide plate 200.

The wavelength converting member 600 receives the light emitted from the light emitting diodes 400 and converts the wavelength. For example, the wavelength converting member 600 may convert blue light emitted from the light emitting diodes 400 into green light and red light. That is, the wavelength converting member 600 converts part of the blue light into green light having a wavelength range of about 520 nm to about 560 nm, and converts the other part of the blue light to a light having a wavelength range of about 630 nm to about 660 nm It can be converted into red light.

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

12 to 14, the wavelength conversion member 600 includes a lower substrate 610, an upper substrate 620, a wavelength conversion layer 630, and a sealing portion 640.

As shown in FIG. 13, the lower substrate 610 is disposed under the wavelength conversion layer 630. The lower substrate 610 is transparent and flexible. The lower substrate 610 may be in close contact with the lower surface of the wavelength conversion layer 630.

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

Further, as shown in FIG. 14, the lower substrate 610 faces the light emitting diodes 400. That is, the lower substrate 610 is disposed between the light emitting diodes 400 and the wavelength conversion layer 630. Further, the upper substrate 620 faces the light guide plate 200. That is, the upper substrate 620 is interposed between the wavelength conversion layer 630 and the light guide plate 200.

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

The wavelength converting member according to this embodiment can be formed by the following procedure.

15, a plurality of first wavelength conversion particles 632, a plurality of second wavelength conversion particles 633, and a plurality of dispersion enhancing particles 535 are formed on a first transparent substrate 611, Is coated. Thereafter, the preliminary wavelength converting layer 635 is formed on the first transparent substrate 611 by being cured by light and / or heat of the resin composition.

Thereafter, the second transparent substrate 621 is laminated on the preliminary wavelength conversion layer 635.

Referring to FIG. 16, the first transparent substrate 611, the preliminary wavelength conversion layer 635, and the second transparent substrate 621 are cut at a time. Accordingly, a plurality of preliminary wavelength conversion members 601 are formed. The preliminary wavelength converting members 601 include a lower substrate 610, a wavelength converting layer 630, and an upper substrate 620, respectively. The lower substrate 610, the wavelength conversion layer 630, and the upper substrate 620 are formed by the same cutting process, and thus include a cut surface 605 disposed on the same plane.

Referring to FIG. 17, the preliminary wavelength converting members 601 are aligned with each other such that the lower substrate 610 and the upper substrate 620 face each other. Thereafter, a sealing portion 640 is formed on the side surface of the preliminary wavelength converting members 601, that is, the cut surface 605.

Thereafter, the wavelength converting members 600 may be detached from each other.

In the liquid crystal display according to the present embodiment, the wavelength conversion layer 630 has a relatively small size. Therefore, in manufacturing the liquid crystal display device according to the present embodiment, a small amount of the first wavelength conversion particles 632 and the second wavelength conversion particles 633 can be used.

Accordingly, the liquid crystal display device according to the present embodiment can reduce the use of the first wavelength conversion particles 631 and the second wavelength conversion particles, and can be easily manufactured at low cost.

18 is an exploded perspective view showing a liquid crystal display device according to the fourth embodiment. 19 is a perspective view showing the wavelength conversion member according to the fourth embodiment. 20 is a cross-sectional view showing a cross section cut along the line C-C 'in FIG. 19; FIG. 21 is a cross-sectional view illustrating one side of a light guide plate, a light emitting diode, and a wavelength conversion member according to the fourth embodiment. In the description of the present embodiment, the description of the preceding embodiments will be made. That is, the description of the preceding liquid crystal display devices can be essentially combined with the description of the present liquid crystal display device except for the changed portions.

Referring to FIGS. 18 to 21, the liquid crystal display according to the present embodiment includes a plurality of wavelength converting members 700. The wavelength converting members 700 correspond to the light emitting diodes 400, respectively.

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

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

18 to 21, the wavelength converting members 700 include a lower substrate 710, an upper substrate 720, a wavelength converting layer 730, and a sealing portion 640.

The features of the lower substrate 710, the upper substrate 720, the wavelength conversion layer 730, and the sealing portion 640 may be substantially the same as those described in the embodiments described above.

In the liquid crystal display device according to the present embodiment, the wavelength conversion layer 730 has a relatively small size. Therefore, in manufacturing the liquid crystal display device according to the present embodiment, a small amount of the first wavelength conversion particles 732 and the second wavelength conversion particles 733 may be used.

Therefore, the liquid crystal display according to the present embodiment can reduce the use of the first wavelength conversion particles 432 and the second wavelength conversion particles 733, and can be easily manufactured at a low cost.

Further, the characteristics of the wavelength converting member 700 can be modified to suit the corresponding light emitting diodes 400, respectively. Accordingly, the liquid crystal display device according to the embodiment can have improved reliability, brightness, and uniform color reproducibility.

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

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (14)

A host layer;
A plurality of dispersion enhancing particles including an inorganic material disposed in the host layer;
A plurality of first wavelength conversion particles disposed in the host layer; And
A plurality of second wavelength conversion particles disposed in the host layer,
Wherein the dispersibility improving particles comprise silicon oxide,
The dispersion improving particles are contained in the host layer in a proportion of 0.5 wt% to 5 wt%
Wherein the first wavelength converting particles comprise a compound semiconductor,
Wherein the second wavelength conversion particles comprise a phosphor,
Wherein the first wavelength conversion particles comprise nanoparticles comprising compound semiconductors and a protective film surrounding the nanoparticles and containing a metal oxide, wherein the nanoparticles comprise compound semiconductors comprising cadmium and zinc,
Wherein the central portion of the nanoparticles has a composition of cadmium higher than that of zinc and an outer portion of the nanoparticles wherein the composition of cadmium is lower than the composition of zinc. The method according to claim 1,
The diameter of the first wavelength conversion particles is 1 nm to 50 nm and the diameter of the second wavelength conversion particles is 1 탆 to 50 탆, the first wavelength conversion particles convert incident light into green light, The wavelength converting particles are optical members for converting incident light into red light. delete delete delete delete delete delete Light source;
A wavelength conversion member into which light emitted from the light source is incident; And
And a display panel on which light emitted from the wavelength converting member is incident,
The wavelength conversion member
A host layer;
A plurality of dispersion enhancing particles including an inorganic material disposed in the host layer;
A plurality of first wavelength conversion particles disposed in the host layer; And
A plurality of second wavelength conversion particles disposed in the host layer,
Wherein the dispersibility improving particles comprise silicon oxide,
The dispersion improving particles are contained in the host layer in a proportion of 0.5 wt% to 5 wt%
Wherein the first wavelength converting particles comprise a compound semiconductor,
Wherein the second wavelength conversion particles comprise a phosphor,
Wherein the first wavelength conversion particles comprise nanoparticles comprising compound semiconductors and a protective film surrounding the nanoparticles and containing a metal oxide, wherein the nanoparticles comprise compound semiconductors comprising cadmium and zinc,
Wherein a center portion of the nanoparticles has a composition of cadmium higher than that of zinc and an outer portion of the nanoparticles wherein the composition of cadmium is lower than the composition of zinc. 10. The method of claim 9,
Wherein the wavelength converting member is disposed in the host layer and includes a plurality of dispersion improving particles including an inorganic material, the dispersion improving particles including silicon oxide,
Wherein the dispersion improving particles are contained in the host layer in a ratio of 0.5 wt% to 5 wt%. delete delete 11. The method according to claim 9 or 10,
Wherein the composition of cadmium becomes smaller as the distance from the center of the nanoparticle to the outer periphery increases, and the composition of zinc increases as the distance from the center of the nanoparticle to the outer periphery increases. 14. The method of claim 13,
Wherein a composition of the cadmium decreases nonlinearly from a center of the nanoparticle to an outer periphery thereof and the composition of the cadmium is reduced so as to have two or more inflection points from a central portion of the nanoparticle to an outer periphery thereof.

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