KR101372098B1 - Optical member and display device - Google Patents

Abstract

An optical member and a display device are disclosed. The display device includes a light source; A light conversion layer to which first light from the light source is incident; A display panel to which the second light from the light conversion layer is incident; And an optional transmission layer interposed between the light source and the light conversion layer based on the path of the first light, wherein the selective transmission layer has a higher transmittance for the first light than the second light.

Description

Optical member and manufacturing method thereof {OPTICAL MEMBER AND DISPLAY DEVICE}

Embodiments relate to an optical member and a display device.

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

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

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

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

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

In order to overcome this problem, a quantum dot bar having a plurality of quantum dots which are converted into red or green wavelengths when blue light is received in front of a blue LED that emits blue light constituting the backlight unit is provided, and the quantum dot bar is irradiated with blue light, thereby Light mixed with blue light, red light and green light is incident on the light guide plate by a plurality of quantum dots dispersed in the bar to provide white light.

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

The backlight unit may be provided with a flexible printed circuits board (FPCB) for transmitting a signal to the LED and supplying power to one side of the blue LED which emits blue light, and an adhesive member may be further provided on the bottom surface of the FPCB.

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

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

Embodiments provide an optical member and a display device having improved luminance and color reproducibility.

A display device according to an embodiment includes a light source; A light conversion layer to which first light from the light source is incident; A display panel to which the second light from the light conversion layer is incident; And an optional transmission layer interposed between the light source and the light conversion layer based on the path of the first light, wherein the selective transmission layer has a higher transmittance for the first light than the second light.

An optical member according to an embodiment includes a substrate; And a light conversion layer disposed on the substrate, wherein the substrate includes a plurality of transparent layers stacked on each other, and refractive indices of transparent layers directly adjacent to each other are different from each other.

The display device according to the embodiment includes the selective transmission layer. In particular, the selective transmissive layer comprises transparent layers stacked on one another. In this case, the transparent layers may transmit light of a specific wavelength band and reflect light of another wavelength band.

The selective transmission layer may transmit light from a light source and reflect light converted in the light conversion layer. In particular, the selective transmission layer may efficiently transmit blue light from the light source, and the red and green light converted in the light conversion layer may be reflected to the display panel.

Thus, the display device according to the embodiment can have improved luminance and color reproducibility.

1 is an exploded perspective view showing a liquid crystal display device according to a first embodiment.
2 is a perspective view illustrating a light conversion sheet.
FIG. 3 is a cross-sectional view showing a section cut along AA 'in FIG. 2. FIG.
4 is a view illustrating a process in which blue light passes through transparent layers.
5 is an exploded perspective view illustrating a liquid crystal display according to a second embodiment.
6 is a perspective view showing a light conversion member according to the second embodiment.
FIG. 7 is a cross-sectional view taken along the line BB ′ of FIG. 6.
8 is a cross-sectional view illustrating a cross section of the light guide plate, the light emitting diode, and the light conversion member.
9 is an exploded perspective view showing a liquid crystal display according to a third embodiment.
10 is a perspective view showing a light conversion member according to the second embodiment.
FIG. 11 is a cross-sectional view illustrating a cross section taken along CC ′ in FIG. 10.
12 is a cross-sectional view illustrating one cross section of the light guide plate, the light emitting diode, and the light conversion member.

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 a light conversion sheet. FIG. 3 is a cross-sectional view taken along the line A-A 'of FIG. 2. 4 is a view illustrating a process in which blue light passes through transparent layers.

1 to 4, 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 plurality of light emitting diodes 400, a printed circuit board 401, and a plurality of optical sheets 500. do.

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

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

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

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

The light emitting diodes 400 may be blue light emitting diodes 400 that generate blue light. That is, the light emitting diodes 400 may generate blue light having a wavelength band between about 400 nm and about 499 nm.

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

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

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

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

The light conversion sheet 501 is disposed on the light guide plate 200. In more detail, the light conversion sheet 501 may be interposed between the light guide plate 200 and the diffusion sheet 502. The light conversion sheet 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 light conversion sheet 501 may convert blue light emitted upward from the light guide plate 200 into green light and red light. That is, the light conversion sheet 501 converts a part of the blue light into green light having a wavelength band of about 500 nm to about 599 nm, and another part of the blue light having a wavelength band of about 600 nm to about 670 nm. Can be converted to red light.

Accordingly, the light that is not converted and passes through the light conversion sheet 501 and the light converted by the light conversion sheet 501 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 liquid crystal panel 20.

The light conversion sheet 501 corresponds to a light conversion member for converting the wavelength of incident light. That is, the light conversion sheet 501 is an optical member that changes the characteristics of incident light.

As shown in FIGS. 2 and 3, the light conversion sheet 501 includes a lower substrate 510, an upper substrate 520, and a light conversion layer 530.

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

In addition, the lower substrate 510 is disposed between the light emitting diode 400 and the light conversion layer 530. In more detail, the lower substrate 510 is interposed between the light emitting diode 400 and the light conversion layer 530 based on a path of light emitted from the light emitting diode 400. That is, the lower substrate 510 is disposed in the optical path after the light is emitted to the light emitting diode 400 and before being incident on the light conversion layer 530.

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

Examples of 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 light conversion layer 530. The lower substrate 510 and the upper substrate 520 support the light conversion layer 530. The lower substrate 510 and the upper substrate 520 protect the light conversion layer 530 from an external physical shock.

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

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

The light conversion layer 530 includes a plurality of light conversion particles 531 and a host layer 532.

The light conversion particles 531 are disposed between the lower substrate 510 and the upper substrate 520. In more detail, the light conversion particles 531 are uniformly dispersed in the host layer 532, and the host layer 532 is disposed between the lower substrate 510 and the upper substrate 520.

The light conversion particles 531 convert wavelengths of light emitted from the light emitting diodes 400. The light conversion particles 531 receive light emitted from the light emitting diodes 400 to convert wavelengths. For example, the light conversion particles 531 may convert blue light emitted from the light emitting diodes 400 into green light and red light. That is, some of the light conversion particles 531 convert the blue light into green light having a wavelength band of about 500 nm to about 599 nm, and another part of the light conversion particles 531 converts the blue light to about 600 It can be converted into red light having a wavelength band between nm and about 670 nm.

That is, when the light emitting diodes 400 are blue light emitting diodes 400 for generating blue light, light conversion particles 531 for converting blue light into green light and red light may be used.

The light conversion particles 531 may be a plurality of quantum dots (QDs). 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 10 nm.

The wavelength of light emitted from the quantum dots can be controlled by the size of the quantum dots or the molar ratio of the molecular cluster compound and the nanoparticle precursor in the synthesis process. 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 host layer 532 surrounds the light conversion particles 531. That is, the host layer 532 uniformly disperses the light conversion particles 531 therein. The host layer 532 may be comprised of a polymer. The host layer 532 is transparent. That is, the host layer 532 may be formed of a transparent polymer.

The host layer 532 is disposed between the lower substrate 510 and the upper substrate 520. The host layer 532 may be in close contact with an upper surface of the lower substrate 510 and a lower surface of the upper substrate 520.

The lower substrate 510 may selectively transmit light. The lower substrate 510 has a high transmittance with respect to blue light from the light emitting diode 400, and has a low transmittance with respect to green light and red light converted by the light conversion layer 530. In addition, the lower substrate 510 has a high reflectance with respect to the green light and the red light.

That is, the lower substrate 510 is a selective transmission layer that selectively transmits incident light for each wavelength band. The lower substrate 510 includes a plurality of transparent layers 511, 512.

The transparent layers 511, 512... Are transparent. The transparent layers 511, 512... Are stacked on each other. The number of the transparent layers 511, 512... May be about 30 to about 60. In more detail, the number of the transparent layers 511, 512... May be about 45 to about 55.

Among the transparent layers 511, 512..., The transparent layers 511, 512..., Adjacent to each other, have different refractive indices. In more detail, the difference in refractive index between the transparent layers 511, 512... Directly adjacent to each other may be about 0.5 to about 1.2.

The transparent layers 511, 512... May include odd-numbered transparent layers 511, 513..., And even-numbered transparent layers 512, 514. That is, the second transparent layer 512 is directly stacked on the first transparent layer 511, and the third transparent layer 513 is directly stacked on the second transparent layer 512 again. Similarly, a fourth transparent layer 514 is directly stacked again on the third transparent layer 513.

The odd-numbered transparent layers 511 to 513 may have a first refractive index and may have a first thickness. The first refractive index may be about 1.3 to 1.6, and the first thickness may be about 135 nm to about 155 nm.

The even-numbered transparent layers 512, 514... Have a second refractive index and may have a second thickness. The second refractive index may be about 2.0 to about 2.5, and the second thickness may be about 83 nm to about 103 nm.

In addition, the odd-numbered transparent layers 511, 513 ... may include a polymer, and the even-numbered transparent layers 512, 514 ... may include an inorganic material. For example, the odd-numbered transparent layers 511 and 513 may include an acrylic resin. The even-numbered transparent layers 512, 514... May include titanium oxide and the like. Accordingly, the odd-numbered transparent layers 511, 513... And the even-numbered transparent layers 512, 514... May constitute an organic-inorganic composite layer.

The transparent layers 511, 512... May be designed to cause constructive interference with respect to the blue light. More specifically, light passing through each of the transparent layers 511, 512... And light reflected twice through the top and bottom surfaces of each of the transparent layers 511, 512... May cause constructive interference with each other. .

The transparent layers 511, 512... May be designed to satisfy Equation 1 below.

Equation 1

2 × n × d = m × λ

Where n is the refractive index of each transparent layer 511, 512 ..., d is the thickness of each transparent layer 511, 512 ..., m is an integer from 1 to 3, and λ is from 400 nm to 499 nm.

For example, the first transparent layer 511 may satisfy the following Equation 2, and the second transparent layer 512 may satisfy the following Equation 3.

Equation 2

2 x n1 x d1 = m x λ

Here, n1 is the refractive index of the first transparent layer 511, d1 is the thickness of the first transparent layer 511, m is an integer of 1 to 3, and λ is 400nm to 499nm. In this case, n1 may be 1.3 to 1.6.

Equation 3

2 x n2 x d2 = m x λ

Where n2 is the refractive index of the second transparent layer 512, d2 is the thickness of the second transparent layer 512, m is an integer of 1 to 3, and λ is 400 nm to 499 nm. In this case, n2 may be 2.0 to 2.5.

In more detail, in Equations 1, 2, and 3, m may be 1.

In addition, the transparent layers 511, 512... May be designed such that constructive interference does not occur with respect to the green light and the red light.

Accordingly, the lower substrate 510 may have a transmittance of about 80% or more with respect to the blue light. In more detail, the lower substrate 510 may have a transmittance of about 80% to about 99% with respect to the blue light. In addition, the lower substrate 510 may have a transmittance of about 50% or less with respect to the red light and the green light, that is, light in a wavelength band of about 500 nm to 670 nm. In more detail, the lower substrate 510 may have a transmittance of about 0% to about 10% with respect to the red light and the green light. In more detail, the lower substrate 510 may have a transmittance of about 0.001% to about 10% with respect to the red light and the green light.

Referring back to FIG. 1, the diffusion sheet 502 is disposed on the light conversion sheet 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., .

And a driving PCB 25 for supplying a driving signal to the gate line and the data line is provided at an edge of the liquid crystal display panel 210.

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

As described above, the liquid crystal display according to the exemplary embodiment efficiently transmits the light emitted from the light emitting diode 400 to the light conversion layer 530 by using the lower substrate 510.

In addition, the lower substrate 510 reflects the green light and the red light converted from the light conversion layer 530 upwards instead of downward. That is, the lower substrate 510 may transmit light from the light emitting diode 400 and reflect light converted by the light conversion layer 530. That is, the lower substrate 510 may further reflect the light converted by the light conversion layer 530 to the liquid crystal display panel.

Thus, the liquid crystal display according to the embodiment may have improved luminance and color reproducibility.

5 is an exploded perspective view illustrating a liquid crystal display according to a second embodiment. 6 is a perspective view showing a light conversion member according to the second embodiment. FIG. 7 is a cross-sectional view taken along the line BB ′ in FIG. 6. 8 is a cross-sectional view illustrating a cross section of the light guide plate, the light emitting diode, and the light conversion member. 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.

5 to 8, the liquid crystal display according to the present exemplary embodiment includes the light conversion member 600 instead of the light conversion sheet 501. The light conversion member 600 is interposed between the light emitting diodes 400 and the light guide plate 200.

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

The light conversion member 600 receives the light emitted from the light emitting diodes 400 and converts the wavelength. For example, the light conversion member 600 may convert blue light emitted from the light emitting diodes 400 into green light and red light. That is, the light conversion member 600 converts a part of the blue light into green light having a wavelength band of about 500 nm to about 599 nm, and another part of the blue light has a wavelength band of about 600 nm to about 670 nm. Can be converted to red light.

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

As illustrated in FIGS. 6 to 8, the light conversion member 600 includes a lower substrate 610, an upper substrate 620, and a light conversion layer 630.

As shown in FIG. 6, the lower substrate 610 is disposed under the light conversion layer 630. The lower substrate 610 may be transparent and flexible. The lower substrate 610 may be in close contact with the bottom surface of the light conversion layer 630.

In addition, as shown in FIG. 7, the lower substrate 610 faces the light emitting diodes 400. That is, the lower substrate 610 is disposed between the light emitting diodes 400 and the light conversion layer 630.

As shown in FIG. 6, the upper substrate 620 is disposed on the light conversion layer 630. The upper substrate 620 may be transparent and flexible. The upper substrate 620 may be in close contact with the top surface of the light conversion layer 630.

In addition, as shown in FIG. 8, the upper substrate 620 faces the light guide plate 200. That is, the upper substrate 620 is disposed between the light guide plate 200 and the light conversion layer 630.

The light conversion layer 630 is interposed between the lower substrate 610 and the upper substrate 620. The light conversion layer 630 is sandwiched by the lower substrate 610 and the upper substrate 620. The light conversion layer 630 may have substantially the same features as the light conversion layer in the above embodiment. In addition, the lower substrate 610 may be substantially the same as the lower substrate in the previous embodiment.

In the liquid crystal display according to the present embodiment, the light conversion layer 630 has a relatively small size. Therefore, in manufacturing the liquid crystal display according to the present embodiment, a small amount of light conversion particles 631 may be used.

Therefore, the liquid crystal display according to the present embodiment can be manufactured easily and at low cost by reducing the use of the light conversion particles 631.

9 is an exploded perspective view showing a liquid crystal display according to a third embodiment. 10 is a perspective view showing a light conversion member according to the second embodiment. FIG. 11 is a cross-sectional view taken along the line CC ′ in FIG. 10. 12 is a cross-sectional view illustrating one cross section of the light guide plate, the light emitting diode, and the light conversion member. 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.

9 to 12, the liquid crystal display according to the present exemplary embodiment includes a plurality of light conversion members 700. The light conversion members 700 correspond to the light emitting diodes 400, respectively.

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

In addition, the light conversion members 700 convert the wavelengths of light emitted from the corresponding light emitting diodes 400. In this case, the light conversion members 700 convert the light emitted from the light emitting diodes into light of a first wavelength such as green light and second light of the second wavelength such as red light. It can be divided into light conversion members.

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

In addition, as illustrated in FIGS. 10 to 12, the light conversion members 700 include a lower substrate 710, an upper substrate 720, and a light conversion layer 730.

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

In the liquid crystal display according to the present embodiment, the light conversion layer 730 has a relatively small size. Therefore, in manufacturing the liquid crystal display according to the present embodiment, a small amount of light conversion particles 731 may be used.

Therefore, the liquid crystal display according to the present embodiment can be manufactured easily and at low cost by reducing the use of the light conversion particles 731.

In addition, the characteristics of each of the light conversion members 700 may be modified to suit the corresponding light emitting diodes. Accordingly, the liquid crystal display according to the embodiment may have improved luminance and uniform color reproduction.

In addition, the features, structures, effects and the like described in the embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects and the like illustrated in the embodiments 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 (12)

Light source;
A light conversion sheet including a light conversion layer to which first light from the light source is incident;
A diffusion sheet to which the second light from the light conversion sheet is incident; And
And a display panel disposed on the diffusion sheet.
The light conversion sheet,
An optional transmission layer interposed between the light source and the light conversion layer based on the path of the first light; And
Further comprising a substrate interposed between the light conversion layer and the diffusion sheet based on the path of the second light,
The selective transmission layer has a higher transmittance for the first light than the second light. The method of claim 1, wherein the light conversion layer is disposed under the diffusion sheet,
The selective transmission layer is in direct contact with the lower surface of the light conversion layer. The method of claim 1, wherein the selective transmission layer
A plurality of first transmission layers having a first refractive index; And
And second transmission layers stacked alternately with the first transmission layers and having a second refractive index different from the first refractive index. The display device of claim 3, wherein the first refractive index is 1.3 to 1.6 and the second refractive index is 2.0 to 2.5. The method of claim 1, wherein the first light has a wavelength of 400nm to 499nm,
The second light has a wavelength of 500nm to 670nm. The display device of claim 1, wherein the first light is blue light and the second light is red light or green light. The display device of claim 1, wherein the selective transmission layer comprises a plurality of transmission layers satisfying the following formula.
Equation
2 × n × d = m × λ
Where n is the refractive index of the transmission layer, d is the thickness of the transmission layer, m is an integer of 1 to 3, and λ is 400 nm to 499 nm. The display device of claim 7, wherein the transmission layers are 30 to 60. A lower substrate;
A light conversion layer disposed on the lower substrate;
An upper substrate disposed on the light conversion layer; And
A diffusion sheet disposed on the upper substrate,
The lower substrate includes a plurality of transparent layers stacked on each other,
An optical member having different refractive indices of transparent layers directly adjacent to each other among the transparent layers. The optical member of claim 9, wherein the transparent layers satisfy the following formula.
Equation
2 × n × d = m × λ
Where n is the refractive index of the transmission layer, d is the thickness of the transmission layer, m is an integer of 1 to 3, and λ is 400 nm to 499 nm. The method of claim 9, wherein the lower substrate
Having light transmittance of 80% to 99% for light of light in the wavelength range of 400 nm to 499 nm,
An optical member having a transmittance of 0% to 10% for light in the wavelength band of 500 nm to 670 nm. The method of claim 11, wherein the light conversion layer comprises a plurality of light conversion particles,
The light conversion particles convert the incident light into light in a wavelength band of 500 nm to 670 nm.

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