KR102171204B1 - Quantum dot composite film and Backlight unit by using the film - Google Patents

Abstract

The backlight unit includes a substrate, a reflective film on the substrate, a plurality of semiconductor light emitting devices on the reflective film, a quantum dot composite film on the plurality of semiconductor light emitting devices, and an optical film on the quantum dot composite film.
The quantum dot composite film includes a first barrier film, a quantum dot phosphor film on the first barrier film, and a second barrier film on the quantum dot phosphor film. The first barrier film may be a dichroic film.

Description

Quantum dot composite film and Backlight unit by using the film}

The present invention relates to a quantum dot composite film and a backlight unit using the same, and more particularly, to a quantum dot composite film bonded with various photofunctional films and a backlight unit using the same.

In an LCD (Liguid Crystal Diplay) TV that uses a light emitting diode (LED) as a backlight unit (BLU), the LED BLU actually emits light and is one of the most important parts in an LCD TV.

As a method of forming a white LED BLU, a red color showing a small half-width (full width at half maximum, FWHM, as the difference between a pair of wavelength values at a location that has 1/2 of the maximum value in the relative spectral distribution, the unit is nm). There is a method of forming a white LED BLU by combining (Red, R), green (G), and blue (Blue, B) LED chips.

The method of forming a white LED BLU by combining red (Red, R), green (Green, G), and blue (blue, B) LED chips requires a large number of LED chips and an additional feedback system when implementing white. There is a problem with high manufacturing cost.

In addition, there is a method of implementing white by using a combination of a blue LED chip and a yellow (Y) phosphor having a wide half-width emission wavelength, which reduces the number of LED chips to 1/3 and eliminates the need for a feed pack system. As a result, the BLU production cost can be significantly reduced. However, due to the use of a phosphor with a large half width, a color filter (CF) that makes the spectrum red, green, and blue with good color purity was required, and due to the light blocking in a wide wavelength range by this CF There is a problem in that the light extraction efficiency of the device is low, and the color purity is poor, thus showing limited color reproduction.

Therefore, in recent years, research to improve the problem of lowering the light extraction efficiency due to the light blocking of a wide area by CF by replacing the existing phosphor with a large half width with a quantum dot with a small half width, and at the same time improving better color reproducibility. Is actively progressing.

Quantum dots are particles in which nano-sized II-IV semiconductor particles form the core. Fluorescence of these quantum dots is light generated when electrons excited from a conduction band to a valence band come down.

In the development of lighting using quantum dot phosphors, quantum dots can emit light of various wavelengths depending on the composite material and the size of the quantum dot, and the half width of the emission beam is also adjustable. Due to the physical characteristics such as a narrow half-width and emission beams of various wavelengths, it is possible not only to develop lighting similar to sunlight but also to develop a BLU capable of high color reproduction.

However, in applying the quantum dot phosphor to such an application field, various expensive photofunctional films are essentially required in order to obtain uniform flat light within a short distance as it goes to a thin-film structure.

These various photofunctional films have a very disadvantageous problem in terms of thickness as well as cost of optical devices.

The problem to be solved by the present invention is to provide a quantum dot composite film bonded with various photofunctional films.

Another problem to be solved by the present invention is to provide a backlight unit including a quantum dot composite film bonded with various photofunctional films.

According to an aspect of the embodiment, a backlight unit includes a substrate; A reflective film on the substrate; A plurality of semiconductor light emitting devices on the reflective film; A quantum dot composite film on the plurality of semiconductor light emitting devices; And an optical film on the quantum dot composite film. The quantum dot composite film includes a first barrier film, a quantum dot phosphor film on the first barrier film, and a second barrier film on the quantum dot phosphor film. The first barrier film may be a dichroic film.

The dichroic film may be a dichroic mirror.

The dichroic film may have a laminated structure of two or more films having different refractive indices.

The semiconductor light emitting device may include a blue light emitting device.

The quantum dot phosphor film may include a green quantum dot phosphor and a red quantum dot phosphor.

The reflective film may include at least one of phenyl propanol amine (PPA), epoxy molding compound (EMC), micro cell polyethylene terephthalate (MCPET), and a metal material.

A diffusion plate may be further included between the semiconductor light emitting device and the quantum dot composite film.

The quantum dot phosphor film may be a hole pattern, a line pattern, a groove pattern, or an uneven pattern.

According to the present invention, by applying a dichroic mirror barrier film as a barrier film of a quantum dot composite film to a backlight unit, the reaction between the quantum dot phosphor and the source beam by increasing the reflectance of the source beam emitted from the semiconductor light emitting device (interaction) Can increase Accordingly, uniform light with high light conversion efficiency can be produced.

In addition, it is possible to provide a quantum dot composite film in which optical functions are combined in combination, such as integrating a patterned reflective film. Therefore, by manufacturing the backlight unit using the quantum dot composite film, the number of optical films required in the structure of the backlight unit requiring various optical films can be drastically reduced.

The technical effects of the present invention are not limited to those mentioned above, and other technical effects that are not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a cross-sectional view showing a quantum dot composite film according to an embodiment of the present invention.
2 is a schematic diagram showing a quantum dot composite film and a method of manufacturing the same according to an embodiment of the present invention.
3 is a cross-sectional view showing a quantum dot composite film according to an embodiment of the present invention.
4 is a cross-sectional view showing a quantum dot composite film according to an embodiment of the present invention.
5 is a cross-sectional view showing a quantum dot composite film according to an embodiment of the present invention.
6 is a cross-sectional view showing a structure of a backlight unit according to an embodiment of the present invention.
7 is a cross-sectional view showing a structure of a backlight unit according to an embodiment of the present invention.
8 is a cross-sectional view illustrating a structure of a backlight unit according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

While the present invention allows various modifications and variations, specific embodiments thereof are illustrated and shown in the drawings, and will be described in detail below. However, it is not intended to limit the present invention to the particular form disclosed, but rather the present invention encompasses all modifications, equivalents and substitutions consistent with the spirit of the present invention as defined by the claims.

When an element such as a layer, region or substrate is referred to as being “on” another component, it will be understood that it may exist directly on another element or there may be intermediate elements between them. .

Although terms such as first, second, etc. may be used to describe various elements, components, regions, layers and/or regions, these elements, components, regions, layers and/or regions It will be understood that it should not be limited by these terms.

The quantum dot composite film according to an embodiment of the present invention includes a first barrier film, a quantum dot phosphor film on the first barrier film, and a second barrier film on the quantum dot phosphor film.

In this case, the first barrier film or the second barrier film serves to prevent the penetration of moisture and oxygen into the quantum dot phosphor film. Accordingly, the lifetime of the quantum dot phosphor may be increased by the first barrier film and the second barrier film.

The structure of the first barrier film or the second barrier film may be in a form in which various materials are laminated. For example, the structure of the first barrier film or the second barrier film may be formed as a dichroic mirror that increases the reflectance of only a specific wavelength beam by adjusting the stacked material, thickness, and number of layers. For example, it can be formed by laminating two or more types of films having different refractive indices.

Therefore, when a quantum dot composite film including a barrier film having a dichroic mirror structure is applied to a backlight unit using a light emitting device, the reflectance of the source beam emitted from the light emitting device can be increased, and the source It can increase the recycling effect of the beam. Accordingly, according to the increased recycling effect of the source beam, the probability of encountering the source beam and the quantum dot is increased, thereby increasing the light conversion efficiency by the quantum dot.

In addition, the quantum dot composite film of the present invention may further include a patterned reflective film positioned between the quantum dot phosphor film and the second barrier film. In this case, the quantum dot phosphor film may be patterned, and the pattern of the quantum dot phosphor film may be a hole pattern, a line pattern, or an uneven pattern.

In this case, the patterned reflective film may have a structure in which at least a part of the patterned structures of the quantum dot phosphor film is filled.

In addition, the patterned reflective film may be positioned on the patterned structure of the quantum dot phosphor film. For example, a patterned reflective film may be positioned on the pattern corresponding to the patterned structure of the quantum dot phosphor film.

In addition, a composite film having an opposite structure in which the structure of the quantum dot composite film described above is reversed is also possible. For example, such a quantum dot composite film includes a first barrier film, a patterned reflective film positioned on the first barrier film, a quantum dot phosphor film positioned on the patterned reflective film, and a second barrier positioned on the quantum dot phosphor film. It may include a film.

1 is a cross-sectional view showing a quantum dot composite film according to an embodiment of the present invention.

In FIG. 1, after placing the quantum dot composite film 400 of the present invention on a substrate 100 on which a reflective film 200 and a semiconductor light emitting device 300 are sequentially stacked, light emitted from the semiconductor light emitting device 300 ( Source beam).

Referring to FIG. 1, the quantum dot composite film 400 includes a first barrier film 410, a quantum dot phosphor film 420 positioned on the first barrier film 410, and an agent positioned on the quantum dot phosphor film 420. 2 It includes a barrier film 430. The second barrier film 430 at this time is a dichroic mirror barrier film.

The quantum dot phosphor film 420 may include at least one type of quantum dot phosphor.

The type of quantum dot according to the present invention is not particularly limited, and examples include II-VI, III-V groups, etc., and representative examples are CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, GaN, It may be any one selected from the group consisting of GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, Si, Ge, and mixtures thereof.

For example, the quantum dot phosphor film may include a first quantum dot phosphor 421 and a second quantum dot phosphor 422.

At this time, the quantum dot phosphor film 420 has a structure in which quantum dot phosphors 421 and 422 are distributed in a resin (resin 424). Meanwhile, the quantum dot phosphor film 420 may further include a scattering agent 423. The scattering agent 423 may increase the amount of light scattered when the source beam passes through the quantum dot phosphor film 420, thereby increasing the case where the source beam and the quantum dot phosphor meet.

The semiconductor light emitting device 300 is a blue LED chip, the first quantum dot phosphor 421 of the quantum dot phosphor film 420 is a green quantum dot phosphor, and the second quantum dot phosphor 422 is a red quantum dot phosphor. In this case, when the blue light (B) emitted from the blue LED chip passes through the quantum dot composite film 400, some light is transmitted as it is, and some light meets the quantum dot phosphors 421 and 422 and thus green light (G) and It turns into red light (R) and is emitted upwards.

In this case, some light may increase the reflectance of the blue light B as the source beam due to the dichroic mirror structure, and the recycling effect of the source beam may increase according to the increase in reflectance. According to the increased recycling effect of the source beam, the probability of meeting the blue light (B) as the source beam with the quantum dot phosphor is increased, so that the light conversion efficiency by the quantum dot phosphor may be increased.

In this way, when the first barrier film 410 or the second barrier film 420 has a dichroic mirror structure, the reflectance of the source beam can be increased, and this increase in reflectance increases the recycling effect of the source beam. As a result, the interaction between the quantum dot phosphor and the source beam is increased, and uniform light with high light conversion efficiency can be produced.

2 is a schematic diagram showing a quantum dot composite film and a method of manufacturing the same according to an embodiment of the present invention.

Referring to FIG. 2, the quantum dot composite film 400 includes a first barrier film 410, a quantum dot phosphor film 420 positioned on the first barrier film 410, and an agent positioned on the quantum dot phosphor film 420. 2 It includes a barrier film 430. In addition, the first barrier film 410 or the second barrier film 430 may be a dichroic mirror barrier film.

In this case, the quantum dot composite film 400 may have a pattern shape. For example, the quantum dot composite film 400 may have an embossed shape. For example, at least one of the first barrier film 410, the quantum dot phosphor film 420, and the second barrier film 430 may have an embossed shape.

The structure of the embossed shape of the quantum dot composite film 400 may be manufactured through a temperature-controllable rolling process.

For example, as shown in FIG. 2, an anode-type roll is disposed on the upper portion of the quantum dot composite film 400, and a cathode-type roll is disposed under the quantum dot composite film 400, and the quantum dot composite film ( 400) can be manufactured in an embossed shape.

Meanwhile, a reflective film-integrated quantum dot composite film including a patterned reflective film will be described in detail through the examples of FIGS. 3 to 5.

3 is a cross-sectional view showing a quantum dot composite film according to an embodiment of the present invention.

Referring to FIG. 3, the quantum dot composite film 400 includes a first barrier film 410, a quantum dot phosphor film 420 positioned on the first barrier film 410, and an agent positioned on the quantum dot phosphor film 420. 2 It includes a barrier film 430. In addition, the first barrier film 410 or the second barrier film 420 may be a dichroic mirror barrier film.

In this case, the quantum dot phosphor film 420 may have a pattern structure. For example, the upper portion of the quantum dot phosphor film 420 may have an uneven pattern.

Accordingly, the patterned reflective film 430 may have a pattern structure in which at least a portion of the uneven patterns of the quantum dot phosphor film 420 is filled.

4 is a cross-sectional view showing a quantum dot composite film according to an embodiment of the present invention.

Referring to FIG. 4, the quantum dot composite film 400 includes a first barrier film 410, a quantum dot phosphor film 420 positioned on the first barrier film 410, and an agent positioned on the quantum dot phosphor film 420. 2 It includes a barrier film 430. In addition, the first barrier film 410 or the second barrier film 430 may be a dichroic mirror barrier film.

In this case, the quantum dot phosphor film 420 may be a hole pattern. Meanwhile, the patterned reflective film 440 may have a pattern structure in which at least a part of the hole of the pattern of the quantum dot phosphor film 420 is filled.

5 is a cross-sectional view showing a quantum dot composite film according to an embodiment of the present invention.

Referring to FIG. 5, the quantum dot composite film 400 includes a first barrier film 410, a quantum dot phosphor film 420 positioned on the first barrier film 410, and an agent positioned on the quantum dot phosphor film 420. 2 It includes a barrier film 430. In addition, the first barrier film 410 or the second barrier film 430 may be a dichroic mirror barrier film.

In this case, the quantum dot phosphor film 420 may have a hole pattern, and the patterned reflective film 440 may also have the same hole pattern structure corresponding to the hole pattern of the quantum dot phosphor film 420.

In the reflective film-integrated quantum dot composite film in which the patterned reflective film 440 is positioned inside the quantum dot composite film as described above, the source beam is reflected by the patterned reflective film 440 to spread widely in the form of plane light, and spread evenly. The quantum dot phosphor film 420 may react with the light-converted beam, for example, a red beam and a green beam to emit light.

Accordingly, the beam finally transmitted through the reflective film-integrated phosphor composite film becomes a uniform white beam. A quantum dot composite film having such characteristics is advantageous in terms of price because the number of photofunctional optical films used in a thin-film backlight unit (BLU) can be reduced. Furthermore, there is a very advantageous advantage for thin-film lighting.

Hereinafter, a backlight unit using the quantum dot composite film will be described.

6 is a cross-sectional view showing a structure of a backlight unit according to an embodiment of the present invention.

Referring to FIG. 6, the backlight unit includes a substrate 100, a reflective film 200 positioned on the substrate 100, a plurality of semiconductor light emitting devices 300 positioned on the reflective film 200, and a semiconductor light emitting device. A patterned reflective film 500 positioned on the device 300, a quantum dot composite film 400 positioned on the patterned reflective film 500, and an optical film 700 positioned on the quantum dot composite film 400 Include.

The quantum dot composite film 400 at this time includes a first barrier film 410, a quantum dot phosphor film 420 positioned on the first barrier film, and a second barrier film 430 positioned on the quantum dot phosphor film 420 It may include. In addition, the first barrier film 410 or the second barrier film 430 at this time may be a dichroic mirror barrier film.

At this time, the substrate 100 may be a circuit board, for example, a printed circuit board (PCB).

The reflective film 200 is positioned on the substrate 100 so that the light emitted from the semiconductor light emitting device 300, which will be described later, reflects light traveling in the lower direction, that is, the substrate direction, and is emitted upward.

These reflective films 200 include PPA (Phenyl Propanol Amine), EMC (Epoxy Molding Compound), MCPET (Micro Cell PolyEthylene Terephthalate), silver (Ag), and excellent reflective aluminum metal (Al metal), etc. It may be a material prepared by mixing beads having reflection, transmission, or refractive properties such as SiO ₂ with a resin.

The semiconductor light emitting device 300 may be a light emitting diode having a first cladding layer, a second cladding layer, and a light emitting layer (active layer) interposed therebetween. The first cladding layer may be a semiconductor layer implanted with a first type impurity, for example, an n-type impurity. Such n-type impurities may be Si, N, B, or P. Also, the second cladding layer may be a semiconductor layer implanted with a second type impurity, that is, a p-type impurity. Such p-type impurities may be Mg, N, P, As, Zn, Li, Na, K, or Cu. In addition, the active layer may have a quantum dot structure or a multi quantum well structure. For example, the semiconductor light emitting device 300 may be a gallium nitride-based light emitting diode emitting blue light.

The patterned reflective film 500 is positioned on the semiconductor light emitting device 300. A support substrate 501 may be further included under the patterned reflective film 500 to support the patterned reflective film 500. This support substrate 501 is a transparent material and any material capable of supporting the patterned reflective film 500 may be used. Meanwhile, in some cases, the support substrate 501 may be omitted.

This patterned reflective film 500 is a reflective sheet that transmits only a part of light emitted from the semiconductor light emitting device and re-reflects the rest, and a plurality of screening patterns are formed. I can.

The patterned reflective film 500 presented in this embodiment is a hole patterned reflective sheet, and a plurality of holes are formed on the sheet. That is, light emitted from the semiconductor light emitting device 300 or reflected from the reflective film 200 positioned on the substrate 100 passes through these holes, and light hitting other areas is transferred to the reflective film 200. Can be re-reflected.

In addition, the holes may have a larger radius as the distance from the center of the semiconductor light emitting device 300 increases, so that the transmission amount of light at a point spaced apart from the semiconductor light emitting device 300 may be set to be greater than the amount of reflection. This is because the closer to the semiconductor light emitting device 300, the stronger the light intensity, and the further away from the semiconductor light emitting device 300, the weaker the light intensity. Therefore, in order to keep the luminance of light uniformly across the entire display panel, it is preferable that the transmittance increases as the distance from the semiconductor light emitting device 300 increases and the transmittance decreases as the distance to the semiconductor light emitting device 300 increases.

Meanwhile, a spacer (not shown) for maintaining a constant distance between the semiconductor light emitting device 300 and the patterned reflective film 500 may be further included. These spacers may have various shapes such as a bar shape extending in a straight line or a shape in which a plurality of short ribs are arranged at regular intervals. These spacers are made of PC (Poly Carbonate), PMMA (Poly Methyl Methacrylate), glass, resin, PPA (Phenyl Propanol Amine), aluminum metal, etc., so that light can be transmitted, refracted or reflected. In addition, as a method of mounting such a spacer, it is possible to apply an adhesive to the upper and lower surfaces of the spacer 25 and perform UV curing or thermal curing.

The quantum dot composite film 400 includes a first barrier film 410, a quantum dot phosphor film 420 and a second barrier film 430. The first barrier film 410 or the second barrier film 430 may be a dichroic mirror barrier film.

The optical film 700 may include optical films of various functions. For example, the optical film 700 may include an optical sheet such as a lower polarizing plate, a color filter substrate, and an upper polarizing plate. Since the structure and function of the optical film is the same as that of a conventional flat panel display panel, a detailed description will be omitted.

In addition, a diffusion plate 600 positioned between the patterned reflective film 500 and the quantum dot composite film 400 or between the quantum dot composite film 400 and the optical film 700 may be further included.

The diffuser plate 600 has a series of arrangements and serves to evenly diffuse the irregular light generated by the light source arranged on the bottom of the backlight unit, that is, the semiconductor light emitting device 300, and can serve as a local area for various optical sheets. .

7 is a cross-sectional view showing a structure of a backlight unit according to an embodiment of the present invention.

Referring to FIG. 7, the structure of the backlight unit of FIG. 6 is the same except that the quantum dot composite film 400 has a pattern shape.

That is, at least one of the first barrier film 410, the quantum dot phosphor film 420, and the second barrier film 430, which is a configuration of the quantum dot composite film 400, has an embossed shape.

The unit size of the embossed shape may be the size of the light emitting device unit. In addition, it may be larger than the light emitting device unit.

Accordingly, the incidence angle of light emitted from the semiconductor light emitting device can be increased due to the embossed structure. For example, when a blue beam emitted from a blue LED enters the embossed quantum dot composite film 400, the reflectance of the blue beam increases, thereby increasing the spread of light. Accordingly, a uniform white beam may be formed as a beam emitted through the quantum dot composite film 400.

8 is a cross-sectional view illustrating a structure of a backlight unit according to an embodiment of the present invention.

Referring to FIG. 8, the backlight unit includes a substrate 100, a reflective film 200 positioned on the substrate 100, a plurality of semiconductor light emitting devices 300 positioned on the reflective film 200, and such a semiconductor. A quantum dot composite film 400 positioned on the light emitting device 300 and an optical film positioned on the quantum dot composite film 400 are included.

The quantum dot composite film 400 at this time is a first barrier film 410, a quantum dot phosphor film 420 positioned on the first barrier film 410, and a patterned reflective film positioned on the quantum dot phosphor film 420 440 and a second barrier film 430 positioned on the patterned reflective film 440.

In addition, the first barrier film 410 or the second barrier film 430 may be a dichroic mirror barrier film.

That is, since the patterned reflective film 440 is included in the quantum dot composite film 400, a separate reflective film is not required.

The quantum dot phosphor film 420 may have a pattern structure. The pattern of the quantum dot phosphor film 420 presented in the present invention is a hole pattern. However, the present invention is not limited thereto, and the quantum dot phosphor film 420 may have various patterns. For example, the quantum dot phosphor film 420 may have a structure such as a line pattern, a groove pattern, or an uneven pattern.

In this case, the patterned reflective film 440 may have a structure in which at least part of the pattern structures of the quantum dot phosphor film 420 is filled.

In addition, the patterned reflective film 440 may be positioned on the patterned structure of the quantum dot phosphor film 420.

Meanwhile, the patterned reflective film 440 may be positioned between the quantum dot phosphor film 420 and the second barrier film 430 as described above, but the first barrier film 410 and the quantum dot phosphor film 420 It can also be located between. In this case, light emitted from the light emitting device meets the quantum dot composite film through the patterned reflective film. Therefore, since one more film is positioned between the light emitting device and the quantum dot composite film, the possibility of deterioration of the quantum dot composite film is lowered.

According to the present invention, by applying a dichroic mirror barrier film as a barrier film of a quantum dot composite film to a backlight unit, the reaction between the quantum dot phosphor and the source beam by increasing the reflectance of the source beam emitted from the semiconductor light emitting device (interaction) Can increase Accordingly, uniform light with high light conversion efficiency can be produced.

In addition, the number of optical films required in the structure of the backlight unit requiring various optical films is drastically reduced by manufacturing the backlight unit by using a quantum dot composite film in which optical functions are combined, such as integrating a patterned reflective film. I can.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are only presented specific examples to aid understanding, and are not intended to limit the scope of the present invention. In addition to the embodiments disclosed herein, it is apparent to those of ordinary skill in the art that other modified examples based on the technical idea of the present invention may be implemented.

100: substrate 200: reflective film
300: semiconductor light emitting device 400: quantum dot composite film
410: first barrier film 420: quantum dot phosphor film
421: first quantum dot 422: second quantum dot
423: scattering agent 424: resin
430: second barrier film 440, 500: patterned reflective film
501: support substrate 600: diffusion plate
700: optical film

Claims (8)

Board;
A plurality of semiconductor light emitting devices on the substrate;
A reflective film disposed on the plurality of semiconductor light emitting devices and having a hole pattern reflective sheet including a plurality of holes;
A diffusion plate in contact with the upper surface of the reflective film;
A quantum dot composite film on the diffusion plate; And
Including an optical film on the quantum dot composite film,
The quantum dot composite film,
A backlight unit comprising a first barrier film on the diffusion plate, a quantum dot phosphor film on the first barrier film, and a second barrier film on the quantum dot phosphor film, wherein the first barrier film is a dichroic film. The method of claim 1,
The dichroic film is a backlight unit of a dichroic mirror. The method of claim 1,
The semiconductor light emitting device is a backlight unit including a blue light emitting device emitting blue light. The method of claim 3,
The dichroic film is a backlight unit including two or more laminated layers having different refractive indices to reflect blue light transmitted through the first barrier film. The method of claim 1,
The quantum dot phosphor film is a backlight unit including a green quantum dot phosphor and a red quantum dot phosphor. delete delete delete

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