KR101744871B1 - Liquid crystal display device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display (LCD), and more particularly, to improvement in brightness and color gamut of a liquid crystal display device using an LED as a light source.
A feature of the present invention is to coat a quantum dot in which red light emitting nano particles and green light emitting nano particles are mixed on the light incident surface of a light guide plate of a backlight unit including a blue LED.
As a result, the blue light emitted from the blue LED achieves a white light having excellent optical characteristics in the process of passing through the quantum dots in which the red light emitting nano particles and the green light emitting nano particles are mixed.
Therefore, the color reproduction ratio of the liquid crystal display device is improved, and as a result, the color coordinate system of BT.709, which is the color coordinate system showing the color reproduction ratio of HDTV (High Definition Television), is satisfied.
Further, by coating the light-incoming surface of the light guide plate with the quantum dot, the process for separately providing the quantum dot can be eliminated, thereby improving the efficiency of the process and preventing the occurrence of damage to the quantum dot. It is possible to prevent the problem that the color reproduction rate of the image is lowered or the material cost is increased.

Description

[0001] Liquid crystal display device [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display (LCD), and more particularly, to improvement in brightness and color gamut of a liquid crystal display device using an LED as a light source.

A liquid crystal display device (LCD), which is advantageous for moving picture display and has a large contrast ratio and is actively used in TVs and monitors, exhibits optical anisotropy and polarization properties of a liquid crystal, And the like.

Such a liquid crystal display device has a liquid crystal panel in which a liquid crystal panel is interposed between two adjacent substrates through a liquid crystal layer as an essential component and changes the alignment direction of the liquid crystal molecules in an electric field in the liquid crystal panel to realize a difference in transmittance do.

However, since the liquid crystal panel does not have its own light emitting element, a separate light source is required to display the difference in transmittance as an image. To this end, a backlight having a light source is disposed on the back surface of the liquid crystal panel.

Here, as a light source of the backlight unit, a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp, a light emitting diode (LED) .

In particular, LEDs are widely used as light sources for displays, having characteristics such as small size, low power consumption, and high reliability.

The LED used as a light source of the liquid crystal display device is composed of an LED chip emitting light and a phosphor. When light is emitted from the LED chip, the emitted light excites the phosphor to emit white light.

A typical white LED device uses a blue LED including a blue LED chip having excellent luminous efficiency and brightness, and uses yttrium aluminum garnet (YAG: Ce) doped with cerium, that is, a yellow phosphor as a phosphor.

Some blue light emitted from the blue LED is transmitted through the phosphor and mixed with the yellow light emitted by the phosphor, thereby realizing white light.

However, the liquid crystal display device using the blue LED as the light source has a problem that the brightness is increased but the color reproduction rate is reduced.

That is, in a liquid crystal display device using a blue LED as a light source, the color reproduction rate does not satisfy the color coordinate system of BT.709, which is a color coordinate system showing the color reproduction ratio of HDTV (High Definition Television).

SUMMARY OF THE INVENTION It is an object of the present invention to improve the brightness and color gamut of a liquid crystal display device using a blue LED as a light source.

In order to achieve the above-mentioned object, the present invention provides a liquid crystal display comprising: a reflection plate; A light guide plate mounted on the reflection plate and coated with quantum dots on the light incident surface; An LED assembly including a plurality of LEDs arranged along the light incident surface of the light guide plate and emitting light toward the light incident surface, and a PCB on which the plurality of LEDs are mounted; An optical sheet that is seated on the light guide plate; A liquid crystal panel mounted on the plurality of optical sheets; A support main body covering an edge of the liquid crystal panel; And a cover bottom formed of a bottom surface in close contact with the support main back surface and a side surface of the cover bottom. The quantum dot provides white light by exciting light emitted from the plurality of LEDs.

At this time, the quantum dot is fixed to the light-incoming surface of the light guide plate through an adhesive material, the adhesive material completely surrounds the quantum dot, and the adhesive material is transparent.

One side of the adhesive material is in contact with the light incident surface of the quantum dot and the light guide plate, the other side of the adhesive material is in contact with a surface of the LED from which the light is emitted, And then it hardens.

The LED is a blue LED that emits blue light. The quantum dot is mixed with red light emitting nano particles and green light emitting nano particles having a quantum confinement effect, and the LED is a blue LED that emits blue light , And the quantum dot is a yellow light emitting nanoparticle having a quantum confinement effect.

The red light emitting nanoparticles, the green light emitting nanoparticles, and the yellow light emitting nanoparticles may be selected from the group consisting of CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe or HgS, CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe, ZnSe, ZnSe, ZnTe, ZnS, HgTe and HgS, and a core containing any one material selected from the group consisting of CdSe, CdTe, CdS, And HgS. ≪ / RTI >

As described above, according to the present invention, the quantum dots in which the red light emitting nano particles and the green light emitting nano particles are mixed are coated on the light incidence surface of the light guide plate of the backlight unit including the blue LED, so that the blue light emitted from the blue LED, The white light having excellent optical characteristics can be realized in the course of passing through the quantum dots in which the particles and the green luminescent nanoparticles are mixed.

Therefore, it is possible to improve the color reproduction rate of the liquid crystal display device. Further, by coating the light-incoming surface of the light guide plate with the quantum dot, the process for separately providing the quantum dot can be eliminated, Therefore, it is possible to prevent the occurrence of breakage of the quantum dot, thereby reducing the color reproduction rate of the image or increasing the material cost.

1 is an exploded perspective view of a liquid crystal display device according to an embodiment of the present invention;
Fig. 2 is a cross-sectional view schematically showing a partial cross-section of the modulated Fig. 1; Fig.
3 is a graph showing BT.709 overlap ratio on a color coordinate system of a liquid crystal display device including a backlight unit including a quantum dot plate according to an exemplary embodiment of the present invention.
4A to 4C are process drawings showing a method of coating a quantum dot according to an embodiment of the present invention on a light incoming surface of a light guide plate according to a process flow.

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

1 is an exploded perspective view of a liquid crystal display device according to an embodiment of the present invention.

As shown, the liquid crystal display includes a liquid crystal panel 110, a backlight unit 120, a support main body 130 for modulating the liquid crystal panel 110 and the backlight unit 120, a cover bottom 150, (140).

The liquid crystal panel 110 and the backlight unit 120 are modularized through the top cover 140, the support main 130 and the cover bottom 150, The top cover 140 is opened so that an image formed on the liquid crystal panel 110 is displayed on the top cover 140 in a rectangular shape having a cross section bent in the shape of "a" so as to cover the top and side edges of the top cover 140.

The cover bottom 150 on which the liquid crystal panel 110 and the backlight unit 120 are mounted and which is the basis for assembling the entire structure of the liquid crystal display device has a horizontal surface 151 adhered to the back surface of the backlight unit 120, And a side surface 153 vertically bent upward.

The support main body 130 having a square shape and having one opened edge which is placed on the cover bottom 150 and covers the edges of the liquid crystal panel 110 and the backlight unit 120 is supported by the top cover 140, Is combined with the bottoms (150).

The support main body 130 is provided with a protrusion 131 for separating the positions of the liquid crystal panel 110 and the backlight unit 120 from each other. The liquid crystal panel 110 is supported on the protrusion 131.

The cover main body 130 may be referred to as a guide panel or a main support or a mold frame. The cover main body 130 may be referred to as a bottom cover or a bottom cover, I will.

The liquid crystal panel 110 plays a key role in image display and includes a first substrate 112 and a second substrate 114 which are bonded to each other with a liquid crystal layer interposed therebetween.

At this time, a plurality of gate lines and data lines intersect to define the pixels on the inner surface of the first substrate 112, which is usually referred to as a lower substrate or an array substrate, although not shown in the drawing, A thin film transistor (TFT) is provided at each of the intersections and is connected in one-to-one correspondence with the transparent pixel electrodes formed in each pixel.

On the inner surface of the second substrate 114 called an upper substrate or a color filter substrate, color filters of red (R), green (G), and blue (B) And a black matrix for covering the gate lines, the data lines, and the thin film transistors. In addition, color filters of red (R), green (G), and blue (B) colors and transparent common electrodes covering the black matrix are provided.

A polarizing plate (not shown) for selectively transmitting only specific light is attached to the outer surfaces of the first and second substrates 112 and 114, respectively.

A printed circuit board 117 is connected to at least one edge of the liquid crystal panel 110 via a connection member 116 such as a flexible circuit board or a tape carrier package (TCP) And is properly brought into close contact with the side surface of the main body 130 or the back surface of the cover bottom 150.

When the thin film transistor selected for each gate line is turned on by the on / off signal of the gate driving circuit, the liquid crystal panel 110 transmits the signal voltage of the data driving circuit to the corresponding pixel electrode through the data line. The arrangement direction of the liquid crystal molecules is changed by the electric field between the pixel electrode and the common electrode to show a difference in transmittance.

In addition, the liquid crystal display device according to the present invention is provided with a backlight unit 120 for supplying light from the rear surface of the liquid crystal display panel so that the difference in transmittance of the liquid crystal panel 110 is externally expressed.

The backlight unit 120 includes an LED assembly 129, a white or silver reflective plate 125, a light guide plate 123 mounted on the reflective plate 125, and an optical sheet 121 interposed therebetween.

The LED assembly 129 is disposed on one side of the light guide plate 123 so as to face the light incident surface of the light guide plate 123. The LED assembly 129 includes a plurality of LEDs 129a, And a PCB 129b which is mounted separately.

At this time, the LED 129a is made of a blue LED that emits blue light having a wavelength of about 430 nm to 450 nm to improve luminous efficiency and luminance.

In the backlight unit 120 of the present invention, a quantum dot 210 is coated on a light-incoming surface of a light guide plate 123 facing a blue LED 129a emitting blue light. Is fixed through the adhesive material (220).

The backlight unit 120 of the present invention implements white light having excellent optical characteristics by the quantum dots 210 coated on the light incident surface of the light guide plate 123. [ Thus, the liquid crystal display of the present invention improves the color reproduction rate even when the blue LED 129a having a low color reproduction rate is used as the light source of the backlight unit 120. [

Particularly, in the liquid crystal display of the present invention, since the quantum dot 210 is coated on the light-incident surface of the light guide plate 123 and integrated with the light guide plate 123, the process for separately providing the quantum dot 210 can be eliminated .

That is, in order to provide the quantum dots 210 between the blue LED 129a and the light incident surface of the light guide plate 123 in order to realize white light having excellent optical characteristics, the quantum dots 210 are cured in a bar shape And the cured bar-shaped quantum dots should be attached to the blue LED 129a and the light incident side of the light guide plate 123 through an adhesive material (not shown) such as a double-sided tape, Can be deleted.

In addition, the cured bar-shaped quantum dots can easily break, and the liquid crystal display of the present invention can prevent such a problem from occurring. Let me take a closer look at this later.

The blue light emitted from the plurality of blue LEDs 129a passes through the quantum dot 210 coated on the light incident surface of the light guide plate 123 and is realized as white light having excellent optical characteristics and is incident into the light guide plate 123, 123 of the light guide plate 123 are uniformly spread over a wide area of the light guide plate 123 by total reflection within the light guide plate 123 to provide a surface light source to the liquid crystal panel 110. [

The reflection plate 125 is disposed on the back surface of the light guide plate 123 and reflects light passing through the back surface of the light guide plate 123 toward the liquid crystal panel 110 to improve the brightness of light.

The optical sheet 121 on the light guide plate 123 includes a diffusion sheet and at least one light condensing sheet and diffuses or condenses the light passing through the light guide plate 123 to provide a more uniform surface light source to the liquid crystal panel 110 Let it enter.

The above-described liquid crystal display device has a structure in which the quantum dots 210 are coated on the light incident surface of the light guide plate 123 so that the blue light emitted from the blue LED 129a is incident into the light guide plate 123 through the light incident surface of the light guide plate 123 Since the quantum dots 210 are realized as white light having excellent optical characteristics, the color reproduction ratio is improved as compared with the conventional art. Thus, the color reproduction ratio of the liquid crystal cell of the present invention satisfies the color coordinates of BT.709.

Since the quantum dots 210 are integrated with the light guide plate 123 by being coated on the light incidence surface of the light guide plate 123, the process for separately providing the quantum dots 210 can be eliminated, do.

In addition, since the quantum dot 210 is not cured to form a bar shape, it is possible to prevent the quantum dots 210 cured in a bar shape from being broken.

FIG. 2 is a cross-sectional view schematically showing a part of a section of FIG. 1 modularized. FIG. 3 is a cross-sectional view of a BT 709 on a color coordinate system of a liquid crystal display device having a backlight unit including a quantum dot plate according to the first embodiment of the present invention. Fig.

2, the light guide plate 123 coated with the quantum dots 210 on the light-entering surface, the optical sheets 121 on the LED assembly 129 and the light guide plate 123 are stacked, Thereby forming a backlight unit (120 in FIG. 1).

A liquid crystal panel 110 in which a liquid crystal layer (not shown) is interposed between the first and second substrates 112 and 114 and the backlight unit 120 Polarizers 119a and 119b for selectively transmitting only specific light are attached to the outer surfaces of the two substrates 112 and 114, respectively.

The backlight unit 120 and the liquid crystal panel 110 are surrounded by the support main body 130 and the cover bottom 150 formed by the horizontal surface 151 and the side surface 153 is coupled to the back surface of the backlight unit 120 A top cover 140 covering the top and side surfaces of the liquid crystal panel 110 is coupled to the support main 130 and the cover bottom 150.

The LED assembly 129 is disposed on one side of the light guide plate 123 to face the light incident surface coated with the quantum dots 210 of the light guide plate 123. The LED assembly 129 includes a plurality of blue LEDs 129a, And a PCB 129b on which a plurality of blue LEDs 129a are mounted with a predetermined spacing therebetween.

The LED assembly 129 is fixed in position by adhesion or the like so that the blue light emitted from the plurality of blue LEDs 129a faces the light incident surface of the light guide plate 123. For this purpose, The LED assembly 129 is attached to the lower surface of the protrusion 131 through an adhesive material (not shown) on the lower surface of the protrusion 131, And is fixed.

This structure is referred to as a side view type.

That is, the LED assembly 129 is configured such that the blue light emitted from the plurality of blue LEDs 129a is parallel to the PCB 129b, and the light incident surfaces of the PCB 129b and the light guide plate 123 are positioned perpendicular to each other.

Here, only one blue LED 129a of the LED assembly 129 is illustrated, but a plurality of blue LEDs 129a are mounted on the PCB 129b at predetermined intervals, do.

Here, the PCB 129b is an electronic circuit board that prints a wiring pattern (not shown) on an insulating layer such as a resin or a ceramic to enable electrical connection with mounting of various electronic devices. The PCB 129b is an epoxy- A flexible printed circuit board (FPCB), or a metal core printed circuit board (MCPCB).

In recent years, MCPCB is being used more and more in order to rapidly dissipate heat generated from the blue LED 129a. At this time, when forming the MCPCB, it is preferable to further form an insulation layer (not shown) such as a polyimide resin material for electrical insulation between the metal MCPCB and the wiring pattern (not shown).

The light guide plate 123 is made of plastic material such as polymethylmethacrylate (PMMA) or polycarbonate (PC), which is an acrylic transparent resin, which is one of the transparent materials capable of transmitting light. It is made in flat type.

The light guide plate 123 includes a pattern of a specific pattern on its back surface to supply a uniform surface light source. The pattern may include an elliptical pattern, an elliptical pattern, A polygon pattern, a hologram pattern, and the like.

In the backlight unit 120 of FIG. 1, quantum dots 210 are coated on the light-incoming surfaces of the light guide plate 123 facing the blue LED 129a emitting blue light.

That is, the light guide plate 123 is coated with a quantum dot 210. The quantum dot 210 is completely wrapped around the adhesive material 220 by the adhesive force of the adhesive material 220 And is fixed to the light entrance surface of the light guide plate 123.

At this time, it is preferable that the adhesive material 220 is also adhered to the blue LED 129a, and the adhesive material 220 is preferably a transparent adhesive material.

That is, one side of the adhesive material 220 is in contact with the light-incoming surface of the quantum dot 210 and the light guide plate 123, and the other side of the adhesive material 220 is in contact with the front of the blue LED 129a.

Accordingly, the white light realized as the blue light emitted from the blue LED 129a passes through the quantum dot 210 coated on the light incident surface of the light guide plate 123 can be incident into the light guide plate 123 without any loss of light.

The blue light emitted from the blue LED 129a is incident on the quantum dot 210 in a state where the red light emitting nanoparticles and the green light emitting nanoparticles are mixed and the quantum dots 210 in which the red light emitting nanoparticles and the green light emitting nanoparticles are mixed, The white light having excellent optical characteristics is realized.

Therefore, the white light having excellent optical characteristics is incident into the light guide plate 123 and the white light incident into the light guide plate 123 is uniformly spread to the wide area of the light guide plate 123 while advancing in the light guide plate 123 by several total reflection Thereby providing the liquid crystal panel 110 with a surface light source of excellent white light.

Here, the quantum dot 210 is a particle of a predetermined size having a quantum confinement effect, while the quantum dot 210 is a mixture of light emitting nanoparticles. It is also called a quantum dot.

Luminescent nanoparticles are semiconductor crystals of several nanometers (nm) in size, which are produced by chemical synthesis. They convert the wavelength of light emitted from the light source and emit the light. The emission wavelength varies according to the size of the particles. .

The diameters of these light emitting nanoparticles are in the range of 1 to 10 nm.

The light emitting nanoparticles may be a group II-VI, III-V, or IV group material, and specifically, CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, InP, GaP, GaInP2, PbS, ZnO, TiO2, AgI , AgBr, Hg12, PbSe, In2S3, In2Se3, Cd3P2, Cd3As2 or GaAs.

In addition, the light emitting nanoparticles may have a core-shell structure. Wherein the core comprises any one material selected from the group consisting of CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe and HgS and the shell comprises CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe and HgS And the like.

Such a light emitting nanoparticle can easily obtain seven colors of rainbow colors including red, green and blue depending on the light of various wavelengths according to the quantum size effect.

That is, the wavelength of emitted light is changed according to the size of the light emitting nanoparticles.

For example, when CdSe is used as the light emitting nanoparticles, when the light emitting nanoparticles are irradiated with light, the wavelength of the emitted light changes according to the size of CdSe. When CdSe has a diameter of about 1.7 nm, it emits blue light, emits green light when it has a diameter of 2.3 nm, and emits red light when it has a diameter of 5.0 nm.

Since the light emitting nanoparticles having a quantum confinement effect have excellent color purity, white light having excellent optical characteristics can be obtained. Since various light colors can be realized by controlling the size of the luminescent nanoparticles, various light can be easily obtained by using a single light source according to the luminescent nanoparticles to be used.

Accordingly, the backlight unit 120 of FIG. 1 of the present invention is configured such that the red light emitting nano particles and the red light emitting nano particles are incident on the light incident surface of the light guide plate 123, which is the blue light emitted from the blue LED 129a, The blue light emitted from the blue LED 129a passes through the quantum dot 210 to realize a white light having excellent optical characteristics, and the white light is transmitted through the light guide plate As shown in FIG.

That is, when the blue light is emitted from the blue LED 129a, the blue light is converted into red light by the wavelength of the blue light by the red light emitting nanoparticles of the quantum dot 210 in the process of passing through the quantum dot 210, The wavelength of the blue light is converted by the light emitting nanoparticles and converted into green light.

Accordingly, the blue light emitted from the blue LED 129a, the red light realized by the red light emitting nanoparticles, and the green light realized by the green light emitting nanoparticles are mixed with each other to realize white light having excellent optical characteristics.

As a result, the liquid crystal display of the present invention improves the color reproduction ratio of the liquid crystal display device even though the blue LED 129a having a low color reproduction rate is used as the light source of the backlight unit (120 in Fig. 1).

Therefore, the color coordinate system of BT.709, which is the color coordinate system representing the color reproduction ratio of HDTV (High Definition Television), is satisfied.

3 is a graph illustrating BT.709 overlap ratio on a color coordinate system of a liquid crystal display device having a backlight unit including a light guide plate coated with quantum dots on a light incidence surface according to an embodiment of the present invention.

As shown, it can be seen that the overlap ratio of BT.709 on the color coordinates of the liquid crystal display according to the embodiment of the present invention is 98%.

2) of the liquid crystal panel (110 in FIG. 2) through the white light realized in the course of passing the blue light emitted from the blue LED (129a in FIG. 2) through the quantum dot (210 in FIG. 2) G.) and a blue (B) color filter layer (not shown), the color reproduction ratio is substantially similar to that of BT.709, which is a color coordinate system representing the color reproduction ratio of HDTV (High Definition Television) .

Here, the color recall ratio refers to a range of colors that a display device including a liquid crystal display device can express, which measures the color coordinates and luminance of red (R), green (G), and blue (B) Color Reproduction can be obtained for 3 Primary Colors.

The color coordinates are the scientific quantities that are typically displayed to measure the color and then distinguish each, and coordinate values of red (700 nm), green (546.1 nm), and blue (435.8 nm) on Illumination) on the coordinate system specified in 1931.

More specifically, the color reproduction ratio can be calculated by connecting the color coordinates of each of red (R), green (G) and blue (B) determined on the color coordinate system. It can be calculated by comparing with the area of the NTSC (International TV Standards Committee) color coordinate.

That is, the color recall ratio is expressed as a ratio of the relative area when assuming that the value of the color coordinate area of NTSC is 100.

Accordingly, if the color coordinate system of BT.709, which is a color coordinate system representing the color reproduction ratio of the HDTV (High Definition Television), is realized with the area A, the blue light emitted from the blue LED 129a in FIG. 2 according to the embodiment of the present invention The color reproduction ratio of the liquid crystal display device using the white light, which is realized in the course of passing through the quantum dot (210 of FIG. 2) coated on the light incident surface of the light guide plate (123 of FIG.

Therefore, the above BT.709 overlapping amount refers to the amount of overlapping with the area of A on the color coordinate system, and it can be seen that the area of A and the area of B almost overlap with each other.

Accordingly, the color reproduction ratio of the liquid crystal display device using the white light, which is realized in the process of passing the blue light emitted from the blue LED (129a of FIG. 2) of the present invention through the quantum dot (210 of FIG. 2) Television), which is the color coordinate system of BT.709, which is the color coordinate system representing the color reproduction ratio of the color reproduction system.

2) is formed integrally with the light guide plate 123 (see FIG. 2) so that the quantum dot (210 in FIG. 2) is coated on the light incident surface of the light guide plate 123 It is possible to eliminate the process for separately providing the dot (210 in FIG. 2).

That is, in order to provide quantum dots (210 in FIG. 2) between the blue LED (129a in FIG. 2) and the light guide plate (123 in FIG. 2) to realize white light having excellent optical characteristics, quantum dots 210 are cured in the form of a bar and then the cured bar-shaped quantum dots are adhered to the blue LED (129a in FIG. 2) and the light guide plate (123 in FIG. 2) (Not shown), but the present invention is capable of eliminating all such processes.

Since the bar-shaped cured quantum dots have a very thin thickness, the quantum dots cured in the bar shape are separated from the blue LED (129a in FIG. 2) and the mouth of the light guide plate (123 in FIG. 2) The process of attaching to an optical surface through an adhesive material (not shown) such as a double-sided tape is very difficult.

Particularly, bar-shaped cured quantum dots have low mechanical strength, so that when they are formed in a bar shape, they can be easily broken when an external impact is applied to a modularized liquid crystal display device.

2), blue light emitted from the blue LED (129a in FIG. 2) can not be realized as uniform white light, and some blue light is directly incident on the light guide plate (123 in FIG. 2) Lt; / RTI >

Therefore, in the course of passing through the color filter (not shown), the blue light is mixed with the red and green colors to realize the red and green colors. However, the blue light is mixed with the blue light, The color reproducibility of the display device is lowered.

In addition, when the bar-shaped cured quantum dots are broken, only the broken quantum dots can not be replaced, which causes a problem in that the material cost is increased.

Therefore, the backlight unit (120 in FIG. 1) of the present invention can be used for separately providing the quantum dot (210 in FIG. 2) by coating the light-incoming surface of the light guide plate (123 in FIG. 2) It is possible to improve the efficiency of the process and to prevent the occurrence of breakage of the quantum dot (210 in FIG. 2), thereby lowering the color reproduction rate of the image or increasing the material cost Can also be prevented.

Here, a method of coating the quantum dot (210 of FIG. 2) on the light-incoming surface of the light guide plate (123 of FIG. 2) will be described in more detail.

4A to 4C are process drawings showing a method of coating a quantum dot according to an embodiment of the present invention on a light incoming surface of a light guide plate according to a process flow.

As shown in FIG. 4A, a quantum dot 210 in which red light emitting nano particles and green light emitting nano particles are mixed is coated on the light incident surface of the light guide plate 123.

At this time, the quantum dots 210 are coated on the light-incoming surface of the light guide plate 123 through a method such as spin coating, bar coating, or the like.

Next, as shown in FIG. 4B, the adhesive material 220 is applied to the light-incoming surface of the light guide plate 123 coated with the quantum dot 210.

The adhesive material (220) is characterized in that it has a property of being cured by a warming treatment or a warming treatment.

At this time, the adhesive material 220 may be formed of a transparent polyacrylate resin, an epoxy resin, a phenolic resin, a polyamide resin, a polyimide resin polyimides rein, polyphenylenethers resin, polyphenylenesulfides resin, and the like. Particularly, the polyimide resin or the polyamide resin adhesive material 220 has excellent adhesive performance.

This adhesive material 220 is made of a viscous material and is applied so as to completely cover the quantum dots 210 coated on the light-incoming surface of the light guide plate 123.

Next, as shown in FIG. 4C, the adhesive material 220 applied so as to completely cover the quantum dots 210 is cured by heating or thermosensitive treatment to form quantum dots 210 on the light incidence surface according to the embodiment of the present invention. The light guide plate 123 coated with the light guide plate 210 is completed.

As described above, in the liquid crystal display of the present invention, red light emitting nanoparticles and green light emission (red light emission) are formed on the light incoming surface of the light guide plate (123 in FIG. 4C) of the backlight unit The blue light emitted from the blue LED (129a in FIG. 2) by coating the quantum dot (210 in FIG. 4C) mixed with the nanoparticles is a quantum dot (210 in FIG. 4C) in which red light emitting nanoparticles and green light emitting nanoparticles are mixed, The white light having excellent optical characteristics is realized.

Therefore, the liquid crystal display of the present invention improves the color reproduction rate of the liquid crystal display device even though the blue LED (129a in Fig. 2) having a low color reproduction rate is used as the light source of the backlight unit (120 in Fig. 1). As a result, the color coordinate system of BT.709, which is a color coordinate system representing the color reproduction ratio of HDTV (High Definition Television), is satisfied.

Further, by coating the light-incoming surface of the light guide plate (123 in FIG. 4C) with the quantum dot (210 in FIG. 4C), it is possible to eliminate the process for separately providing the quantum dot (210 in FIG. 4C) And it is possible to prevent the occurrence of breakage of the quantum dot (210 in FIG. 4C), thereby preventing the problem that the color reproduction rate of the image is lowered or the material cost is increased.

In the structure described above, the LED (129a in FIG. 2) as the light source is a blue LED that emits blue light. At this time, the quantum dot (210 in FIG. 4C) coated on the light- The quantum dot (210 in FIG. 4C) may be composed of yellow light-emitting nanoparticles having a quantum confinement effect, or the quantum dots may be formed of a mixture of red light-emitting nanoparticles and green light-emitting nanoparticles. The LED (129a in FIG. 2) may be a red and a green or a UV LED, and the quantum dot (210 in FIG. 4C) is mixed with the light emitted from the LED (129a in FIG. 2) Nanoparticles.

 For example, when the LED (129a in FIG. 2) is a UV LED, quantum dots (210 in FIG. 4C) coated on the light-incoming surface of the light guide plate (123 in FIG. 4C) are mixed with red and green, Structure.

The backlight unit (120 in FIG. 1) of the above-described structure is generally called a side light system. According to the purpose, a plurality of blue LEDs (129a in FIG. 2) Can be arranged in multiple layers.

Further, it is also possible to provide a plurality of LED assemblies (129 in Fig. 2) each in a plurality and to interpose them corresponding to each other along opposite side edges of the cover bottom (150 in Fig. 2).

The present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

110: liquid crystal panel (112, 114: first and second substrates)
119a and 119b: first and second polarizing plates
The light emitting diode (LED) assembly includes a light emitting diode (LED), a blue LED, and a light emitting diode (LED)
130: support main, 131: protrusion, 140: top cover, 150: cover bottom
210: Quantum dot, 220: Adhesive material

Claims (10)

A reflector;
A light guide plate mounted on the reflection plate and coated with quantum dots on the light incident surface;
An LED assembly including a plurality of LEDs arranged along the light incident surface of the light guide plate and emitting light toward the light incident surface, and a PCB on which the plurality of LEDs are mounted;
An optical sheet that is seated on the light guide plate;
A liquid crystal panel seated on the optical sheet;
A support main body covering an edge of the liquid crystal panel;
A support bottom main body having a bottom surface that is in close contact with the support main back surface and a side surface of the bottom surface,
/ RTI >
Wherein the quantum dot emits white light by exciting light emitted from the plurality of LEDs,
Wherein the quantum dots are fixed to the light entrance surface of the light guide plate through an adhesive material,
The adhesive material completely wraps the quantum dot at the top of the quantum dot,
Wherein one side of the adhesive material is in contact with the quantum dot and the light incidence surface and the other side of the adhesive material is in contact with one side of the LED from which the light is emitted.
delete The method according to claim 1,
Wherein the adhesive material is transparent.
delete The method according to claim 1,
Wherein the adhesive material is cured after a lapse of a predetermined time.
The method according to claim 1,
Wherein the LED is a blue LED that emits blue light, and the quantum dot is a red light emitting nanoparticle and a green light emitting nanoparticle having a quantum confinement effect.
The method according to claim 1,
Wherein the LED is a blue LED that emits blue light and the quantum dot is composed of red light emitting nano particles and green light emitting nano particles having a quantum confinement effect or yellow light emitting nano particles.
8. The method of claim 7,
Wherein the red light-emitting nanoparticles, the green light-emitting nanoparticles, and the yellow light-emitting nanoparticles are selected from the group consisting of CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe or HgS.
8. The method of claim 7,
The red light emitting nanoparticles, the green light emitting nanoparticles, and the yellow light emitting nanoparticles may include a core containing any one material selected from the group consisting of CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe and HgS, CdS, ZnSe, ZnTe, ZnS, HgTe, and HgS. The liquid crystal display device according to claim 1, wherein the core-shell structure comprises a shell of any one material selected from the group consisting of CdS, ZnSe, ZnTe, ZnS, HgTe and HgS.
Coating quantum dots on the light-incoming surface of the light guide plate;
Applying an adhesive material on the quantum dot, fixing the quantum dot to the light incidence surface and completely surrounding the quantum dot;
Placing the light guide plate on an upper portion of the reflection plate;
Arranging an LED assembly including a plurality of LEDs emitting light toward the light incidence surface along the light incidence surface and a PCB on which the plurality of LEDs are mounted;
Placing an optical sheet on top of the light guide plate;
Placing a liquid crystal panel on the optical sheet;
Placing a support main at an edge of the liquid crystal panel;
A step of bringing the bottom surface of the cover bottom into close contact with the support main back surface
/ RTI >
Wherein the quantum dot emits white light by exciting light emitted from the plurality of LEDs,
Wherein one side of the adhesive material is in contact with the quantum dot and the light incidence surface and the other side of the adhesive material is in contact with one surface of the LED from which the light is emitted.

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