KR20130009024A - Optical member, display device having the same and method of fabricating the same - Google Patents

Abstract

PURPOSE: An optical member, a display device and a manufacturing method are provided to improve brightness and a color reproduction ratio. CONSTITUTION: A plurality of first wavelength conversion particles(532) is arranged within a host layer. A plurality of second wavelength conversion particles(533) is arranged within the host layer. The host layer includes a first region(531a) and a second region(531b). The second region is arranged under the first region. The second region includes the second wavelength conversion particles with concentration which is higher than the concentration of the first region.

Description

Optical member, display device including same, and manufacturing method therefor {OPTICAL MEMBER, DISPLAY DEVICE HAVING THE SAME AND METHOD OF FABRICATING THE SAME}

Embodiments relate to an optical member, a display device including the same, and a manufacturing method thereof.

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, a light emitting diode (LED) or the like may be applied. In addition, in order to effectively transmit the light output from the light source to the display panel side, a light guide plate, an optical sheet, or the like may be stacked and used.

In this case, an optical member or the like that changes the wavelength of light generated from the light source and injects white light into the light guide plate or the display panel may be applied to the display device. In particular, in order to change the wavelength of light, quantum dots or the like can be used.

Quantum dots have a particle size of 10 nm or less and have unique electro-optic properties depending on their 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, quantum dots emitting RGB or RYGB, which are three primary colors of light, may be formed by spin coating or printing a transparent substrate such as glass. In this case, when the quantum dot emitting yellow (Y) is further included, white light closer to natural light may 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 quantum dots are applied is disclosed in Korean Patent Laid-Open Publication No. 10-2011-0012246.

Embodiments provide an optical member, a display device, and a manufacturing method thereof having improved luminance and color reproducibility.

Optical member according to the embodiment is a host layer; A plurality of first wavelength converting particles disposed in the host layer; And a plurality of second wavelength converting particles disposed in the host layer, wherein the host layer comprises: a first region; And a second region disposed below the first region and including the second wavelength converting particles at a higher concentration than the first region.

A display device according to an embodiment includes a light source; A wavelength conversion member for converting the wavelength of the light emitted from the light source; 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 converting particles disposed in the host layer; And a plurality of second wavelength converting particles disposed in the host layer, wherein the host layer comprises: a first region; And a second region disposed below the first region and including the second wavelength converting particles at a higher concentration than the first region.

An optical member manufacturing method according to an embodiment forms a resin composition comprising a plurality of first wavelength conversion particles and second wavelength conversion particles having a larger diameter than the first wavelength conversion particles, and on the substrate Coating a resin composition, moving the second wavelength converting particles toward the substrate, and curing the resin composition.

The optical member according to the embodiment includes the second wavelength conversion particles at different concentrations for each region. In particular, the optical member according to the embodiment may include the second wavelength conversion particles at a high concentration in the second region.

Accordingly, the optical member according to the embodiment may convert the incident light into the light of the second wavelength such as green light mainly by the second wavelength conversion particles in the second region. In addition, the optical member according to the exemplary embodiment may convert incident light into light having a third wavelength such as red light by the first wavelength converting particles in the first region and the second region.

As described above, the optical member according to the embodiment may change the wavelength band of the light mainly converted for each region. Accordingly, the optical member according to the embodiment may maximize the conversion efficiency of the incident light and have an improved color reproduction rate.

In addition, the first wavelength converting particles and the second wavelength converting particles are disposed in one host layer. That is, the first region and the second region are integrally formed with each other, and no interface is formed between the first region and the second region.

Accordingly, the optical member according to the embodiment can minimize the light loss generated between the first region and the second region, and can improve the brightness.

1 is an exploded perspective view showing a liquid crystal display device according to a first embodiment.
2 is a perspective view illustrating the wavelength conversion member according to the first embodiment.
FIG. 3 is a cross-sectional view taken along the line AA ′ of FIG. 2.
4 and 5 are views illustrating a process of manufacturing the wavelength conversion member according to the first embodiment.
6 is a sectional view showing a wavelength conversion member according to the second embodiment.
FIG. 7 is a diagram illustrating wavelengths versus respective intensities of white light generated by the wavelength conversion member according to the second embodiment.
8 is an exploded perspective view showing a liquid crystal display according to a third embodiment.
9 is a perspective view showing a wavelength conversion member according to a third embodiment.
FIG. 10 is a cross-sectional view taken along the line BB ′ of FIG. 5.
FIG. 11 is a cross-sectional view of a light guide plate, a light emitting diode, and a wavelength conversion member according to a third embodiment.
12 to 14 illustrate a process of forming the wavelength conversion member according to the third embodiment.
15 is an exploded perspective view illustrating a liquid crystal display according to a fourth embodiment.
16 is a perspective view of the wavelength conversion member according to the fourth embodiment.
FIG. 17 is a cross-sectional view taken along the line CC ′ in FIG. 15.
18 is a cross-sectional view illustrating a cross section of the light guide plate, the light emitting diode, and the 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 illustrating the wavelength conversion member according to the first embodiment. FIG. 3 is a cross-sectional view taken along the line A-A 'of FIG. 2. 4 and 5 are views illustrating a process of manufacturing the wavelength conversion member according to the first embodiment.

1 to 3, the liquid crystal display according to the embodiment includes a backlight unit 10 and a liquid crystal panel 20.

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

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

The bottom cover 100 has a shape in which an upper portion thereof is opened. The bottom cover 100 accommodates the light guide plate 200, the light emitting diodes 400, the printed circuit board 401, the reflective sheet 300, and the optical sheets 500.

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

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

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

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

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

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

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

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

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

For example, when the light emitting diodes 400 are blue light emitting diodes, the wavelength conversion member 501 may convert blue light emitted upward from the light guide plate 200 into green light and red light. That is, the wavelength conversion member 501 converts a part of the blue light into green light having a wavelength band of about 520 nm to about 560 nm, and another part of the blue light having a wavelength band of about 630 nm to about 660 nm. Can be converted to red light.

Accordingly, the light that is not converted and passes through the wavelength conversion member 501 and the light converted by the wavelength conversion member 501 may form white light. That is, blue light, green light, and red light may be combined to allow white light to enter the liquid crystal panel 20.

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

As illustrated in FIGS. 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 unit 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 the material used as the upper substrate 520 may include a transparent polymer such as polyethylene terephthalate.

The lower substrate 510 and the upper substrate 520 sandwich the 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 converting layer 530 includes a host layer 531, a plurality of first wavelength converting particles 532, and a plurality of second wavelength converting particles 533.

The host layer 531 surrounds the first wavelength converting particles 532 and the second wavelength converting particles 533. That is, the host layer 531 uniformly disperses the first wavelength converting particles 532 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 an upper surface of the lower substrate 510 and a lower surface of the upper substrate 520.

The host layer 531 may include a first region 531a and a second region 531b. In more detail, the host layer 531 may be divided into the first region 531a and the second region 531b.

The first region 531a is positioned below the upper substrate 520. In more detail, the first region 531a is adjacent to the upper substrate 520.

The first region 531a may be defined by the second wavelength conversion particles 533. That is, the second wavelength converting particles 533 may be hardly disposed in the first region 531a, and the first wavelength converting particles 532 may be mainly disposed. As such, an area in which the second wavelength converting particles 533 are substantially not included is defined as the first area 531a.

In more detail, the first region 531a may be defined on the host layer 531. For example, the first region 531a may be an area of about 1/2 to about 9/10 of the thickness T of the host layer 531 from a lower surface of the upper substrate 520. In more detail, the thickness T1 of the first region 531a may be about 40 μm to 95 μm.

The second region 531b is disposed on the lower substrate 510. In addition, the second region 531b is adjacent to the lower substrate 510. In addition, the second region 531b is disposed below the first region 531a. The second region 531b may be immediately adjacent to the first region 531a.

In addition, the second region 531b is disposed before the first region 531a based on the traveling direction of the light emitted from the light emitting diode 400. That is, light emitted from the light emitting diode 400 passes through the second region 531b and enters the first region 531a.

The first region 531a and the second region 531b may be integrally formed with each other. That is, no interface exists between the first region 531a and the second region 531b.

The second region 531b may be defined by the second wavelength conversion particles 533. That is, the second wavelength conversion particles 533 may be mainly disposed in the second region 531b. As such, an area in which the second wavelength conversion particles 533 are mainly disposed may be defined as the second area 531b.

In more detail, the second region 531b may be defined under the host layer 531. For example, the second region 531b may be an area of about 1/10 to about 1/2 of the thickness T of the host layer 531 from an upper surface of the lower substrate 510. In more detail, the thickness T2 of the second region 531b may be about 5 μm to about 10 μm.

The first wavelength converting particles 532 are disposed between the lower substrate 510 and the upper substrate 520. In more detail, the first wavelength conversion 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. Can be. In addition, the first wavelength conversion particles 532 may be substantially uniformly dispersed in the first region 531a and the second region 531b. In more detail, the first wavelength conversion particles 532 may be dispersed in the first region 531a and the second region 531b at a concentration of about 1 wt% to about 50 wt%.

The first wavelength converting particles 532 convert the wavelength of light emitted from the light emitting diodes 400. The first wavelength converting particles 532 receive light emitted from the light emitting diodes 400 to convert wavelengths. For example, the first wavelength conversion particles 532 may convert blue light emitted from the light emitting diodes 400 into red light. That is, the first wavelength conversion particles 532 may convert the blue light into red light having a wavelength band between about 630 nm and about 660 nm.

When the light emitting diodes 400 are blue light emitting diodes that generate blue light, first wavelength converting particles 532 that convert blue light into red light may be used.

The first wavelength converting particles 532 may be a plurality of quantum dots (QDs). The quantum dot may include a core nanocrystal and a shell nanocrystal surrounding the core nanocrystal. 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 15 nm. In more detail, the diameter of the quantum dot may be about 8 nm to about 11 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.

The second wavelength converting particles 533 are disposed in the host layer 531. In more detail, the second wavelength conversion particles 533 may be mainly disposed in the second region 531b. That is, the second wavelength converting particles 533 may be included in a higher concentration in the second region 531b than in the first region 531a. That is, the second region 531b includes the second wavelength conversion particles 533 at a higher concentration than the first region 531a.

The concentration of the second wavelength conversion particles 533 in the second region 531b may be much higher than the concentration of the second wavelength conversion particles 533 in the first region 531a. In other words, the second wavelength converting particles 533 may be concentrated under the host layer 531.

For example, the second wavelength conversion particles 533 may be included in the second region 531b at a concentration of about 1 wt% to about 50 wt%. In addition, the second wavelength conversion particles 533 may be included in the first region 531a at a concentration of about 0.0001 wt% to about 0.1 wt%. In addition, the concentration of the second wavelength converting particles 533 may increase in the host layer 531 as it moves downward.

The second wavelength conversion particles 533 may have a larger diameter than the first wavelength conversion particles 532. In more detail, the diameters of the second wavelength conversion particles 533 may be about 10 μm to about 30 μm.

The second wavelength conversion particles 533 convert the wavelength of the light emitted from the light emitting diodes 400. The second wavelength converting particles 533 receive light emitted from the light emitting diodes 400 to convert wavelengths. For example, the second wavelength conversion particles 533 may convert blue light emitted from the light emitting diodes 400 into green light. That is, the second wavelength conversion particles 533 may convert the blue light into green light having a wavelength band between about 500 nm and about 600 nm.

When the light emitting diodes 400 are blue light emitting diodes for generating blue light, the second wavelength conversion particles 533 for converting the blue light into green light may be used.

Phosphor may be used as the second wavelength conversion particles 533. As the second wavelength conversion particles 533, a green phosphor may be used. More specifically, examples of the green phosphor include manganese doped zinc silicon oxide based phosphors (eg, Zn 2 SiO 4: Mn), europium doped strontium gallium sulfide based phosphors (eg, SrGa 2 S 4: Eu) or europium doped. Barium silicon oxide chloride type fluorescent substance (for example, Ba5Si2O7Cl4: Eu) etc. are mentioned.

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

Referring to FIG. 4, a plurality of first wavelength converting particles 532 and a plurality of second wavelength converting particles 533 are uniformly dispersed in a silicone resin, an epoxy resin, an acrylic resin, or the like to form a resin composition. . A solvent such as toluene, hexane or chloroform may be added to the resin composition. The solvent may be added in a ratio of about 10 wt% to about 30 wt% with respect to the resin composition.

The solvent may perform a function of lowering the viscosity of the resin composition. The viscosity of the resin composition may be about 100cps to about 10000cps. In more detail, the viscosity of the resin composition may be about 100cps to about 1000cps.

Thereafter, 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 or spray coating.

Referring to FIG. 5, the coated resin composition may be left for about 0.5 hours to about 24 hours so that the lower substrate 510 is positioned below the coated resin composition based on the gravity direction.

Accordingly, since the second wavelength converting particles 533 have a much larger diameter than the first wavelength converting particles 532, the second wavelength converting particles 533 may be precipitated at the bottom of the coated resin composition. In particular, when the viscosity of the resin composition is low, such a precipitation rate can be further accelerated.

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.

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

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

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

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

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 layer may be coated on the lower surface of the lower substrate 510, and the second inorganic protective layer may be coated on the upper surface of the upper substrate 520. Examples of the material used for the first inorganic protective film and the second inorganic protective film include silicon oxide and the like.

The diffusion sheet 502 is disposed on the 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. In addition, 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 that displays an image by 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 polarization filters.

Although not shown in detail in the drawings, the TFT substrate 21 and the color filter substrate 22 will be described in detail. In the TFT substrate 21, a plurality of gate lines and data lines cross each other to define pixels, and respective intersections are performed. A thin flim transistor (TFT) is provided in each region and is connected in one-to-one correspondence with the pixel electrode mounted in each pixel. The color filter substrate 22 includes a color filter of R, G, and B colors corresponding to each pixel, a black matrix bordering each of them, covering a gate line, a data line, a thin film transistor, and the like, and a common electrode covering all of them. Include.

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

The driving 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 tape carrier package (TCP).

As described above, the wavelength conversion member 501 includes the second wavelength conversion particles 533 at different concentrations for each of the first region 531a and the second region 531b. In particular, the wavelength conversion member 501 may include the second wavelength conversion particles 533 at a high concentration in the second region 531b.

Accordingly, the wavelength conversion member 501 may convert the incident light into the light having the second wavelength, such as green light, mainly by the second wavelength conversion particles 533 in the second region 531b. . In addition, the wavelength conversion member 501 may convert the incident light mainly into the light having a third wavelength such as red light by the first wavelength conversion particles 532 in the first region 531a.

As described above, the wavelength conversion member 501 may change the wavelength band of the light mainly converted for each of the first region 531a and the second region 531b. Accordingly, the display device according to the embodiment may maximize conversion efficiency of incident light and have an improved color reproduction rate.

In addition, the first wavelength converting particles 532 and the second wavelength converting particles 533 are disposed in one layer. That is, the first region 531a and the second region 531b are integrally formed with each other, and no interface is formed between the first region 531a and the second region 531b.

Accordingly, the display device according to the embodiment can minimize the light loss generated between the first region 531a and the second region 531b and improve the luminance.

6 is a sectional view showing a wavelength conversion member according to the second embodiment. In the description of the present embodiment, reference is made to the description of the foregoing embodiment. That is, the foregoing description of the liquid crystal display device may be essentially combined with the description of the present liquid crystal display device, except for the changed part.

Referring to FIG. 6, the wavelength conversion member according to the present embodiment includes third wavelength conversion particles 534. The third wavelength converting particles 534 are disposed in the host layer 531. In more detail, the third wavelength conversion particles 534 may be mainly disposed in the second region 531b. That is, the third wavelength conversion particles 534 may be included in a higher concentration in the second region 531b than in the first region 531a. That is, the second region 531b includes the third wavelength conversion particles 534 at a higher concentration than the first region 531a.

The concentration of the third wavelength conversion particles 534 in the second region 531b may be much higher than the concentration of the third wavelength conversion particles 534 in the first region 531a. The third wavelength conversion particles 534 may be included in the second region 531b at a concentration of about 0.1 wt% to about 0.5 wt%. In addition, the third wavelength conversion particles 534 may be included in the first region 531a at a concentration of about 0.05 wt% or less.

The third wavelength conversion particles 534 may have a larger diameter than the first wavelength conversion particles 532. In more detail, the diameter of the third wavelength conversion particles 534 may be about 0.5 μm to about 10 μm.

The third wavelength conversion particles 534 convert the wavelength of light emitted from the light emitting diodes 400. The third wavelength conversion particles 534 receives light emitted from the light emitting diodes 400 to convert wavelengths. 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 band between about 540 nm and 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.

Phosphor may be used as the third wavelength conversion particles 534. A yellow phosphor may be used as the third wavelength conversion particles 534. More specifically, examples of the yellow phosphor include yttrium aluminum garnet (YAG) phosphors and the like.

As shown in FIG. 7, in the white light formed by the third wavelength conversion particles 534 by the wavelength conversion member 501 according to the present embodiment, a wavelength band of about 555 nm to about 560 nm ( The intensity of Y) can be increased. In addition, since the third wavelength conversion particles 534 are mainly disposed in the second region 531b, such an effect may be maximized.

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

8 is an exploded perspective view showing a liquid crystal display according to a third embodiment. 9 is a perspective view showing a wavelength conversion member according to a third embodiment. FIG. 10 is a cross-sectional view taken along the line BB ′ in FIG. 5. FIG. 11 is a cross-sectional view of a light guide plate, a light emitting diode, and a wavelength conversion member according to a third embodiment. 12 to 14 illustrate a process of forming the wavelength conversion member according to the third embodiment. In the description of the present embodiment, reference is made to the description of the foregoing embodiment. That is, the foregoing description of the liquid crystal display device may be essentially combined with the description of the present liquid crystal display device, except for the changed part.

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

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

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

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

9 to 11, the wavelength conversion member 600 includes a lower substrate 610, an upper substrate 620, a wavelength conversion layer 630, and a sealing unit 640.

As shown in FIG. 10, the lower substrate 610 is disposed under the wavelength conversion layer 630. The lower substrate 610 may be transparent and flexible. The lower substrate 610 may be in close contact with the bottom surface of the wavelength conversion layer 630.

In addition, the first region 631a of the wavelength conversion layer 630 faces the light guide plate 200, and the second region 631b of the wavelength conversion layer 630 faces the light emitting diode 400. . That is, the second region 631b is disposed closer to the light emitting diode 400 than the first region 631a.

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

In addition, as shown in FIG. 11, 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. In addition, 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 part 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 part 640 protect the wavelength conversion layer 630 from external physical shocks and chemical shocks.

The wavelength conversion member according to the present embodiment may be formed by the following process.

Referring to FIG. 12, a resin composition including a plurality of first wavelength converting particles 632 and a plurality of second wavelength converting particles 633 is coated on a first transparent substrate 611. Thereafter, the second wavelength conversion particles 633 are deposited on the top surface of the first transparent substrate 611 by gravity. Thereafter, the resin composition is cured by light and / or heat of the resin composition, and a preliminary wavelength conversion layer 635 is formed on the first transparent substrate 611.

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

Referring to FIG. 13, 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. In this case, since the lower substrate 610, the wavelength conversion layer 630 and the upper substrate 620 are formed by the same cutting process, the lower substrate 610, the wavelength conversion layer 630 and the upper substrate 620 includes a cut surface 605 disposed on the same plane.

Referring to FIG. 14, the preliminary wavelength conversion members 601 are aligned with each other such that the lower substrate 610 and the upper substrate 620 face each other. Thereafter, a sealing part 640 is formed on the side surfaces of the preliminary wavelength conversion members 601, that is, the cut surface 605.

Thereafter, the wavelength conversion members 600 may be separated 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 according to the present embodiment, a small amount of the first wavelength converting particles 632 and the second wavelength converting particles 633 may be used.

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

15 is an exploded perspective view illustrating a liquid crystal display according to a fourth embodiment. 16 is a perspective view of the wavelength conversion member according to the fourth embodiment. FIG. 17 is a cross-sectional view taken along the line CC ′ in FIG. 15. 18 is a cross-sectional view illustrating a cross section of the light guide plate, the light emitting diode, and the wavelength conversion member according to the fourth embodiment. In the description of the present embodiment, reference is made to the description of the foregoing embodiments. That is, the foregoing description of the liquid crystal display devices may be essentially combined with the description of the present liquid crystal display device, except for the changed part.

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

In addition, the wavelength conversion members 700 are disposed between the light emitting diodes 400 and the light guide plate 200. That is, each wavelength conversion 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, almost all of the light emitted from each light emitting diode may be incident on the corresponding wavelength converting member 600.

15 to 18, the wavelength conversion members 700 include a lower substrate 710, an upper substrate 720, a wavelength conversion layer 730, and a sealing unit 640.

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

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

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

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

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

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

Claims (11)

Host layer;
A plurality of first wavelength converting particles disposed in the host layer; And
A plurality of second wavelength converting particles disposed in the host layer,
The host layer
First region; And
And a second region disposed below the first region and comprising the second wavelength converting particles at a higher concentration than the first region. The method of claim 1, wherein the first wavelength conversion particles are quantum dots,
The second wavelength conversion particles include a phosphor. The optical member of claim 1, wherein a diameter of the second wavelength conversion particles is larger than a diameter of the first wavelength conversion particles. The optical member of claim 1, wherein the first wavelength converting particles have a diameter of 1 nm to 15 nm, and the second wavelength converting particles have a diameter of 10 μm to 30 μm. The method of claim 1, wherein the first wavelength conversion member converts blue light or ultraviolet light into red light,
The second wavelength conversion member converts blue light or ultraviolet light into green light. The method of claim 5, further comprising a plurality of third wavelength conversion particles disposed in the second region,
And the third wavelength converting particles convert blue light or ultraviolet light into yellow light. Light source;
A wavelength conversion member for converting the wavelength of the light emitted from the light source; And
A display panel to which light emitted from the wavelength conversion member is incident;
The wavelength conversion member
Host layer;
A plurality of first wavelength converting particles disposed in the host layer; And
A plurality of second wavelength converting particles disposed in the host layer,
The host layer
First region; And
And a second area disposed below the first area and including the second wavelength conversion particles at a higher concentration than the first area. The display device of claim 7, wherein the second area is disposed earlier than the first area based on a path of light emitted from the light source. Forming a resin composition comprising a plurality of first wavelength converting particles and second wavelength converting particles having a larger diameter than the first wavelength converting particles,
Coating the resin composition on a substrate,
Move the second wavelength converting particles towards the substrate,
The manufacturing method of the optical member containing hardening the said resin composition. The method of claim 9, wherein a solvent is added to the resin composition,
And the solvent is evaporated from the resin composition when the second wavelength converting particles are moved. The method of claim 9, wherein the second wavelength converting particles are moved downward based on gravity.

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