KR20170113920A - Prism sheet including nano particle and Backlight unit - Google Patents

Abstract

A quantum dot, and inorganic nanoparticles, wherein the quantum dots and inorganic nanoparticles each independently include a prism sheet, an optical sheet including the prism sheet, and a backlight unit including the optical sheet.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a prism sheet including a nanoparticle,

The present disclosure relates to a prism sheet including nanoparticles and a backlight unit.

Recently, researches for application to various industrial fields (display, bio, solar cell, photodetector, illumination, transistor, etc.) using quantum dot are being actively carried out. Among them, light and display using quantum dots are attracting attention in the world market. The quantum dot is a fluorescent nanoparticle having a particle diameter of 2 nm to 10 nm. Since it is possible to adjust the bandgap by the size of the nanocrystals, it has luminescence characteristics depending on the particle size. Also, even if a nano emitter having the same size is used, the luminescent characteristics vary depending on the material to be formed. The properties of such a nano-luminous body are controlled to be variously used in various light emitting devices and electronic devices.

The quantum dots can freely adjust the emission wavelength and have a narrow full width at half maximum (FWHM), as well as being capable of absorbing a broad wavelength while having a high quantum efficiency. However, since the nano luminous body is very vulnerable to ultraviolet rays, heat, and moisture, there is a problem that the life of the electronic apparatus is shortened when the nano luminous body is applied to an electronic apparatus or the like. In particular, various methods for protecting a nano-luminous body from ultraviolet rays, heat, moisture and the like in a film or sheet including a nano-luminous body have been proposed, but there is a limit in blocking moisture penetration into a film or a sheet.

On the other hand, the display device generally uses a white light source that emits white light. The user who observes the display device can see the color image by passing the white light through the color filter. The white light source includes a blue LED chip (light-emitting diode chip) emitting blue light and a light switcher finally emitting a white light using a blue light. YAG (Yttrium Aluminum Garnet), which is a phosphor, is mainly used as the light switching element. However, since the phosphors have a wide range of emission spectrum over the red light wavelength band and the green light wavelength band, there is a limit in increasing the color purity of the color that the white light source using the phosphor passes through the color filter. In addition, the color reproducibility of a display device using a white light source to which the phosphor is applied is low. In order to improve the color reproducibility of a display device, various researches are currently underway to apply a nano emitter having a narrow full width at half maximum (FWHM) and a high power density to a display device. When such a quantum dot is applied to a display, the luminance can be raised and the color reproducibility close to the natural color can be obtained.

However, since the quantum dot applied to the display is included in the form of a separate sheet, there is a problem that the thickness of the final display is thickened and the price competitiveness is poor. Therefore, efforts to solve such a problem are continuing.

One embodiment provides a nanoparticle-containing prism sheet capable of improving luminance and color reproducibility.

Another embodiment provides an optical sheet including the prism sheet.

Another embodiment provides a backlight unit including the optical sheet.

One embodiment provides a prism sheet comprising quantum dots and inorganic nanoparticles, wherein the quantum dots and inorganic nanoparticles in the prism sheet are each independently present.

The quantum dot may have an emission wavelength range of 520 nm to 660 nm.

The quantum dot may include a quantum dot having an emission wavelength range of 600 nm to 660 nm and a quantum dot having an emission wavelength range of 520 nm to 560 nm.

The quantum dot may have a particle diameter of 0.1 nm or more and 100 nm or less.

The quantum dot may have a particle diameter of 0.1 nm or more and 50 nm or less.

The quantum dot may have a core / single shell form, a core / multiple shell form or an alloy form.

The core, shell and alloy may be selected from the group consisting of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS HgZnSeTe, HgZnSTe, GaN, GaP, GaAs, AIN, AlP, AlAs, InN, InP, InAs, GaNP, GaNAs, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSeS, CdHgSeTe, At least one selected from the group consisting of GaAs, GaAs, AlNP, AlNAs, AlPAs, InNP, InNAs, InPAs, GaAlNP, GaAlNAs, GaAlPAs, GaInNP, GaInNAs, GaInPAs, InAlNP, InAlNAs, InAlPAs and SbTe.

The quantum dot may have a full width of half maximum (FWHM) of the emission wavelength spectrum of 45 nm or less.

The inorganic nanoparticles may include titania, zirconia, alumina, silica, or a combination thereof.

The inorganic nanoparticles may be included in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the quantum dots.

Another embodiment provides an optical sheet including the prism sheet.

The optical sheet may not include a barrier film.

Another embodiment provides a backlight unit including the optical sheet.

Other aspects of the present invention are included in the following detailed description.

Since the prism sheet according to the embodiment of the present invention includes quantum dots and inorganic nanoparticles in the prism sheet without a separate film including quantum dots, it is possible to provide an optical sheet capable of high brightness and high color reproduction, and a backlight unit Can be provided. In addition, since a separate quantum dot containing film is unnecessary, a barrier film for protecting the quantum dots is also unnecessary, so that not only the thickness of the entire panel can be reduced but also the economical efficiency is also excellent.

1 schematically shows a conventional optical sheet structure.
2 schematically illustrates a prism sheet according to one embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

In the drawings, the thickness is enlarged to clearly represent the layers and regions. Like parts are designated with like reference numerals throughout the specification.

Whenever a portion of a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the case where it is "directly on" another portion, but also the case where there is another portion in between. Conversely, when a part is "directly over" another part, it means that there is no other part in the middle.

As used herein, the term " combination thereof "means a mixture, a laminate, a composite, an alloy, a blend, a reaction product, and the like of the composition.

Hereinafter, a quantum dot film according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a view schematically showing the structure of a conventional optical sheet 1, and FIG. 2 is a view schematically showing the structure of a prism sheet 10 according to an embodiment.

1, a conventional optical sheet 1 includes a quantum dot film including quantum dots 3, a barrier film 6 disposed on both sides of the quantum dot film, and a barrier film 6, And a prism sheet (2). In the case of the backlight unit, the quantum dot film as described above must be included, so that it is possible to achieve the inherent effects of containing the quantum dots, that is, high brightness and high color reproducibility.

However, due to the addition of the quantum dot sheet, a barrier film for protecting the quantum dots vulnerable to moisture and oxygen must be additionally added, thereby increasing the thickness of the optical sheet, and thus there is a limit to improve the color purity and color reproducibility There is a problem that the price competitiveness is lowered.

2, the prism sheet 10 according to one embodiment includes the quantum dot 3 and the inorganic nanoparticles 4 independently in the prism sheet 10, and the prism sheet 10 includes the prism sheet 10, The thickness of the optical sheet and the backlight unit can be remarkably reduced, thereby achieving superior luminance and color reproducibility, cost reduction effect, and superiority in cost competitiveness.

The prism sheet according to one embodiment includes quantum dots and inorganic nanoparticles independently present, and does not take the form of, for example, the inorganic nanoparticles surrounding the quantum dots. In the case where the quantum dots and the inorganic nanoparticles are independently present, since the quantum dots are superior to the inorganic nanoparticles in that they are surrounded by the inorganic nanoparticles, the optical characteristics such as brightness are excellent and the efficiency is advantageous, Quantum dots can be used to achieve efficiency and brightness equal to or higher than the equivalent level.

The quantum dot may have an emission wavelength range of 520 nm to 660 nm. For example, the quantum dots include i) quantum dots having an emission wavelength range of 520 nm to 560 nm, capable of absorbing a part of blue light from a light source to generate green light, and ii) having an emission wavelength range of 600 nm to 660 nm, And a quantum dot capable of absorbing a part of blue light to generate red light.

The quantum dot may have a particle diameter of 0.1 nm or more and 100 nm or less, for example, 0.1 nm or more and 50 nm or less. When the quantum dots have a particle diameter within the above range, they exhibit optimal color conversion efficiency and can be easily dispersed in the prism sheet together with the inorganic nanoparticles.

The quantum dot may have a core / single shell form, a core / multiple shell form or an alloy form. The core, shell and alloy may be selected from the group consisting of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS HgZnSeTe, HgZnSTe, GaN, GaP, GaAs, AIN, AlP, AlAs, InN, InP, InAs, GaNP, GaNAs, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSeS, CdHgSeTe, , At least one selected from the group consisting of GaPAs, AlNP, AlNAs, AlPAs, InNP, InNAs, InPAs, GaAlNP, GaAlNAs, GaAlPAs, GaInNP, GaInNAs, GaInPAs, InAlNP, InAlNAs, InAlPAs and SbTe. It is not.

For example, the quantum dot may have a core / single shell form or a core / multiple shell form, in which case the bandgap of the shell may be larger than the bandgap of the core. For example, when having a core / multiple shell configuration (core-first shell-second shell), the bandgap of the second shell may be greater than the bandgap of the first shell, Gap. In addition, the quantum dots may have an alloy form. In this case, the quantum dots may have a concentration gradient in which the concentration of a specific element becomes lower toward the center of the alloy quantum dots.

The quantum dot may have a full width of half maximum (FWHM) of the emission wavelength spectrum of 45 nm or less, for example, 30 nm to 40 nm. When the quantum dot has a half-width within the above range, the color purity and color reproducibility of the prism sheet including the quantum dot can be improved.

The inorganic nanoparticles may include titania, zirconia, alumina, silica, or a combination thereof. For example, the inorganic nanoparticles may include titania, zirconia, or alumina. When the above-described quantum dots and inorganic nanoparticles of the above kind are contained in the prism sheet according to one embodiment, self-quenching between quantum dots is prevented, and optical characteristics such as color reproducibility and brightness are excellent. The quantum dot of the prism sheet can achieve sufficient color reproducibility due to the color conversion, so that it is possible to secure the price competitiveness by lowering the production cost in manufacturing the prism sheet according to one embodiment.

The inorganic nanoparticles may be included in an amount of 0.1 to 50 parts by weight, for example, 1 to 30 parts by weight based on 100 parts by weight of the quantum dots. When the inorganic nanoparticles are contained in the above content range, the dispersibility of the quantum dots and the inorganic nanoparticles is improved, and the adjustment of the white point color coordinates by color conversion becomes easy, and the color characteristics such as brightness are excellent.

For example, a plurality of quantum dots and inorganic nanoparticles in the prism sheet according to an exemplary embodiment may independently form a cluster. For example, primary particles of quantum dots having an emission wavelength range of 520 nm to 560 nm form clusters together with inorganic nanoparticles to form secondary particles of the first composite, and light emission wavelengths of 600 nm to 660 nm May form a cluster together with inorganic nanoparticles to form secondary particles of the second composite.

The particle size of the clusters may be less than or equal to about 10 microns, such as between 3 microns and 7 microns. When the cluster has a particle size within the above range, it can exhibit optimal color conversion efficiency and diffusion effect.

The particle diameter of the inorganic nanoparticles may be 10 nm to 5 탆. When the particle size of the nanoparticles is within the above-mentioned range, the inorganic nanoparticles diffuse light and the optical path becomes longer, so that the probability that the light meets the quantum dots causes wavelength conversion. As a result, even a small amount of quantum dots, Reproducibility can be obtained.

Another embodiment provides an optical sheet including the prism sheet.

In general, in the case of an optical sheet including quantum dots, a barrier film for protecting the quantum dots must necessarily be included because of the characteristics of quantum dots vulnerable to moisture and oxygen. However, since the optical sheet according to one embodiment includes the quantum dot in the prism sheet described above, it may not include a separate barrier film, thereby reducing the thickness of the optical sheet and the backlight unit including the optical sheet.

Another embodiment provides a backlight unit including the optical sheet.

Hereinafter, specific embodiments of the present invention will be described. However, the embodiments described below are only intended to illustrate or explain the present invention, and thus the present invention should not be limited thereto.

Example  1: Production of prism sheet

0.4 mg of alumina was mixed with 1 ml of toluene, and then the temperature was raised to 60 캜 to dissolve the alumina.

Thereafter, 20 mg of a red nano luminous body of InP / ZnS system (QD solution, particle diameter of 15 nm) and 20 mg of a green nano luminous body of InP / ZnS system (QD solution, 8 nm Dispersing the solution in which the nano-luminophore is dispersed is mixed with the solution in which the alumina is dissolved and then cooled to room temperature to prepare a dispersion solution in which red luminescent particles, green luminescent particles and alumina are dispersed independently Respectively. The dispersion solution was mixed with urethane acrylate (BASF) and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO, BASF). The photoinitiator was mixed in an amount of 1 part by weight based on 100 parts by weight of urethane acrylate. Thereafter, toluene was removed using an evaporator to prepare a coating composition in which urethane acrylate, red luminescent particles, green luminescent particles, alumina, and photoinitiator were mixed.

Thereafter, the coating composition was coated on one side of a 75 탆 thick PET film and cured to produce a prism sheet comprising red luminescent particles, green luminescent particles and alumina having a height of 25 탆.

Example  2: Manufacture of prism sheet

A prism sheet was prepared in the same manner as in Example 1 except that 4 mg of titania was used instead of 0.4 mg of alumina as the inorganic nanoparticles.

Example  3: Production of prism sheet

A prism sheet was prepared in the same manner as in Example 1, except that 10 mg of zirconia was used instead of 0.4 mg of alumina as the inorganic nanoparticles.

Example  4: Manufacture of prism sheet

A prism sheet was produced in the same manner as in Example 1, except that silica was used instead of alumina as the inorganic nanoparticles.

Comparative Example  1: Production of prism sheet

InP / ZnS based red nano luminous body (Samsung Display) coated with alumina as a nano luminous body (surrounded by) and InP / ZnS system green nano luminous body coated with (surrounded) alumina without using toluene solution in which alumina is dissolved, (Samsung Display Co., Ltd.) was used as a polarizing plate.

Comparative Example  2: Manufacture of prism sheet

A prism sheet was produced in the same manner as in Example 1, except that 10 mg of alumina was used instead of 20 mg.

Comparative Example  3: Production of prism sheet

A prism sheet was produced in the same manner as in Example 1, except that 30 mg of alumina was used instead of 20 mg.

Display Color characteristics  evaluation

Each of the prism sheets according to Examples 1 to 4 and Comparative Examples 1 to 3 was assembled with a light source (blue light emitting diode) to manufacture a backlight unit. The color characteristics of the backlight unit were evaluated, Respectively. In the following Table 1, the gamut ratio is a percentage of the area of the triangle with the RGB color coordinates in each backlight unit relative to the gamut range (hereinafter referred to as NTSC gamut range) based on the National Television Systems Committee (NTSC) PR-655 SpectraScan Spectroradiometer.

Color gamut ratio (%) Brightness (cd / m ² ) Example 1 89.9 341 Example 2 89.1 339 Example 3 88.9 332 Example 4 70.2 305 Comparative Example 1 49.6 263 Comparative Example 2 55.4 299 Comparative Example 3 55.1 292

From the above Table 1, it can be confirmed that the prism sheet according to the first to fourth embodiments has excellent color characteristics as compared with the prism sheet according to the first to third comparative examples.

While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the appended claims.

1: Conventional backlight unit
2: Conventional prism sheet
3: Quantum dot
4: Inorganic nanoparticles
6: Barrier film
10: prism sheet according to one embodiment

Claims (13)

Quantum dots and inorganic nanoparticles,
The quantum dots and inorganic nanoparticles are each independently present
Prism sheet.
The method according to claim 1,
Wherein the quantum dot has an emission wavelength range of 520 nm to 660 nm.
3. The method of claim 2,
Wherein the quantum dot includes a quantum dot having an emission wavelength range of 600 nm to 660 nm and a quantum dot having an emission wavelength range of 520 nm to 560 nm.
The method according to claim 1,
And the quantum dot has a particle diameter of 0.1 nm or more and 100 nm or less.
5. The method of claim 4,
And the quantum dot has a particle diameter of 0.1 nm or more and 50 nm or less.
The method according to claim 1,
Wherein the quantum dot has a core / single shell form, a core / multiple shell form or an alloy form.
The method according to claim 6,
The core, shell and alloy may be selected from the group consisting of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS HgZnSeTe, HgZnSTe, GaN, GaP, GaAs, AIN, AlP, AlAs, InN, InP, InAs, GaNP, GaNAs, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSeS, CdHgSeTe, At least one selected from the group consisting of GaAs, GaAs, AlNP, AlNAs, AlPAs, InNP, InNAs, InPAs, GaAlNP, GaAlNAs, GaAlPAs, GaInNP, GaInNAs, GaInPAs, InAlNP, InAlNAs, InAlPAs and SbTe.
The method according to claim 1,
Wherein the quantum dot has a full width of half maximum (FWHM) of an emission wavelength spectrum of 45 nm or less.
The method according to claim 1,
Wherein the inorganic nanoparticles comprise titania, zirconia, alumina, silica, or a combination thereof.
The method according to claim 1,
Wherein the inorganic nanoparticles are contained in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the quantum dots.
An optical sheet comprising a prism sheet according to any one of claims 1 to 10.
12. The method of claim 11,
Wherein the optical sheet does not include a barrier film.
A backlight unit comprising the optical sheet according to claim 11.

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