KR20120063929A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: A liquid crystal display device is provided to coat a quantum dot which red light-emitting nano particles and green light-emitting nano particles are mixed on a light-incident surface of a light guide plate. CONSTITUTION: A light guide plate(123) is arranged on an upper part of a reflecting plate. A quantum dot is coated on a light-incident surface of the light guide plate. An LED assembly(129) includes a plurality of LEDs according to the light-incident surface of the light guide plate. Optical sheets are settled on the light guide plate. A liquid crystal panel(110) is arranged on a plurality of the optical sheets. A support main(130) protects the edge of the liquid crystal panel.

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, and more particularly, to an improvement in luminance and color reproducibility of a liquid crystal display using an LED as a light source.

Liquid crystal display devices (LCDs), which are used for TVs and monitors due to their high contrast ratio and are advantageous for displaying moving images, are characterized by optical anisotropy and polarization of liquid crystals. The principle of image implementation by

Such a liquid crystal display is an essential component of a liquid crystal panel bonded through a liquid crystal layer between two side-by-side substrates, and realizes a difference in transmittance by changing an arrangement direction of liquid crystal molecules with an electric field in the liquid crystal panel. do.

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

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

Among them, LEDs are particularly widely used as light sources for displays with features such as small size, low power consumption, and high reliability.

On the other hand, the LED used as a light source of the liquid crystal display device is composed of an LED chip and a phosphor that emits light, and 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 a 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 a light source has a problem in that luminance is increased but color reproduction is decreased.

That is, a liquid crystal display device using a blue LED as a light source does not satisfy the color coordinates of BT.709, which is a color coordinate system indicating color reproduction ratio of a high definition television (HDTV).

The present invention has been made to solve the above problems, and an object of the present invention is to improve luminance and color reproducibility of a liquid crystal display device using a blue LED as a light source.

In order to achieve the object as described above, the present invention is a reflection plate; A light guide plate mounted on the reflective plate and coated with a quantum dot on a light incident surface; An LED assembly arranged along a light incident surface of the light guide plate, the LED assembly including a plurality of LEDs emitting light toward the light incident surface, and a PCB on which the plurality of LEDs are mounted; An optical sheet seated on the light guide plate; A liquid crystal panel mounted on the plurality of optical sheets; A support main covering the edge of the liquid crystal panel; A cover bottom including a bottom surface and a side surface thereof in close contact with the support main back surface may be provided. The quantum dot may provide a liquid crystal display device that excites the light emitted from the plurality of LEDs to implement white light.

In this case, the quantum dot is fixed to the light incident surface of the light guide plate through an adhesive material, the adhesive material completely surrounds the quantum dot, and the adhesive material is transparent.

In addition, 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 contacting material is in contact with one surface from which the light of the LED is emitted, the adhesive material is a predetermined time When this passes, it hardens.

The LED is a blue LED emitting blue light, and the quantum dot is a mixture of red light emitting nanoparticles and green light emitting nanoparticles having a quantum confinement effect, and the LED is a blue LED emitting blue light. The quantum dot is a yellow light emitting nanoparticle having a quantum confinement effect.

Here, the red light emitting nanoparticles, the green light emitting nanoparticles and the yellow light emitting nanoparticles are made of one selected from CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe or HgS, the red light emitting nanoparticles and the green light emitting nanoparticles Nanoparticles and the yellow light emitting nanoparticles are CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe and HgS containing a material selected from the group consisting of CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe And a core-shell structure consisting of a shell of any material selected from the group consisting of HgS.

As described above, in the present invention, the blue light emitted from the blue LED is coated with the red light emitting nanoparticles by coating a quantum dot in which red light emitting nanoparticles and green light emitting nanoparticles are mixed on the light incident surface of the light guide plate of the backlight unit including the blue LED. In the process of passing through the quantum dot in which the particles and the green light emitting nanoparticles are mixed, there is an effect of realizing white light having excellent optical properties.

Therefore, there is an effect of improving the color reproduction of the liquid crystal display device, and by coating the quantum dots on the light incident surface of the light guide plate, the process for separately providing the quantum dots can be eliminated, and the efficiency of the process can be improved. There is an effect, it is possible to prevent the breakage of the quantum dot, thereby reducing the color reproducibility of the image, it is also possible to prevent the problem that the material cost increases.

1 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view of a partial cross section of FIG. 1 modularized. FIG.
3 is a graph showing the BT.709 superposition ratio on the color coordinates of the liquid crystal display device having a backlight unit including a quantum dot plate according to an embodiment of the present invention.
4A to 4C are process diagrams illustrating a method of coating a quantum dot on a light incident surface of a light guide plate according to an embodiment of the present invention 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 according to an exemplary embodiment of the present invention.

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

Looking at each of them in more detail, the liquid crystal panel 110 and the backlight unit 120 is modularized through the top cover 140, the support main 130 and the cover bottom 150, the top cover 140 is a liquid crystal panel A rectangular frame having a cross section bent in a shape of “a” so as to cover the top and side edges of the 110 may be configured to display an image implemented in the liquid crystal panel 110 by opening the front surface of the top cover 140.

In addition, 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 apparatus of the liquid crystal display device, has a horizontal surface 151 and an edge thereof closely contacting the rear surface of the backlight unit 120. It consists of a side 153 vertically bent upwards.

Then, the support main 130 having a rectangular frame shape, which is seated on the cover bottom 150 and opens at one edge of the liquid crystal panel 110 and the backlight unit 120, has a top cover 140 and a cover. It is coupled with the bottom 150.

The support main 130 is provided with a protrusion 131 that distinguishes the positions of the liquid crystal panel 110 and the backlight unit 120 from the inside thereof, and the liquid crystal panel 110 is mounted on and supported by the protrusion 131.

In this case, the top cover 140 may also be referred to as a case top or a top case, and the support main 130 may also be referred to as a guide panel, a main support, or a mold frame, and the cover bottom 150 may be referred to as a bottom cover or a lower cover. It is also built.

In addition, the liquid crystal panel 110 plays a key role in image expression and includes a first substrate 112 and a second substrate 114 bonded to each other with the liquid crystal layer interposed therebetween.

At this time, although not shown in the drawings under the premise of an active matrix method, a plurality of gate lines and data lines intersect each other and a pixel is defined on an inner surface of the first substrate 112, which is commonly referred to as a lower substrate or an array substrate. A thin film transistor (TFT) is provided at each crossing point to be connected one-to-one with a transparent pixel electrode formed in each pixel.

An inner surface of the second substrate 114, called an upper substrate or a color filter substrate, may correspond to each pixel, for example, a color filter of red (R), green (G), and blue (B) color, and these. A black matrix is provided covering each of the gate lines, the data lines, and the thin film transistors. In addition, a transparent common electrode covering the red (R), green (G), and blue (B) colors and the black matrix is provided.

In addition, polarizing plates (not shown) for selectively transmitting only specific light are attached to the outer surfaces of the first and second substrates 112 and 114, respectively.

Along the at least one edge of the liquid crystal panel 110, the printed circuit board 117 is connected through a connecting member 116 such as a flexible circuit board or a tape carrier package (TCP) to support the modularization process. The side surface of the main 130 or the cover bottom 150 is properly folded to be in close contact.

When the thin film transistor selected for each gate line is turned on by the on / off signal of the gate driver circuit, the liquid crystal panel 110 transmits the signal voltage of the data driver 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, indicating a difference in transmittance.

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

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

The LED assembly 129 is located at one side of the light guide plate 123 to face the light incident surface of the light guide plate 123, and the LED assembly 129 has a plurality of LEDs 129a and a plurality of LEDs 129a at regular intervals. It includes a PCB (129b) to be spaced apart.

In this case, the LED 129a includes a blue LED emitting blue light having a wavelength of about 430 nm to 450 nm to improve luminous efficiency and luminance.

In addition, the backlight unit 120 of the present invention is coated with a quantum dot 210 on the light incident surface of the light guide plate 123 facing the blue LED 129a emitting blue light. It is characterized in that the fixing through the adhesive material 220.

By the quantum dot 210 coated on the light incident surface of the light guide plate 123, the backlight unit 120 of the present invention realizes white light having excellent optical characteristics. Accordingly, in the liquid crystal display of the present invention, the color reproducibility is improved even when the blue LED 129a having a low color reproducibility is used as the light source of the backlight unit 120.

In particular, 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 formed integrally with the light guide plate 123, the process for separately providing the quantum dot 210 may be eliminated. .

That is, in order to provide a quantum dot 210 between the blue LED 129a and the light guide plate 123 incident surface in order to realize white light having excellent optical characteristics, the quantum dot 210 is cured to a bar shape. In addition, the cured bar-shaped quantum dots should be attached to the blue LED 129a and the light guide plate 123 through an adhesive material (not shown) such as a double-sided tape, respectively. You can delete it.

In addition, the cured bar-shaped quantum dot can be easily broken, the liquid crystal display of the present invention can prevent this problem from occurring. We will discuss this in more detail later.

As such, the blue light emitted from the plurality of blue LEDs 129a passes through the quantum dot 210 coated on the light guide plate 123 to the light incident surface, and thus is implemented as white light having excellent optical characteristics, and is incident into the light guide plate 123. The white light incident into the inside of the light guide plate 123 is uniformly spread in a wide area of the light guide plate 123 by several total reflections in the light guide plate 123 to provide a surface light source to the liquid crystal panel 110.

The reflective plate 125 is positioned on the rear surface of the light guide plate 123, and reflects light passing through the rear surface of the light guide plate 123 toward the liquid crystal panel 110 to improve the brightness of the light.

The optical sheet 121 on the light guide plate 123 includes a diffusion sheet and at least one light collecting sheet, and diffuses or collects light passing through the light guide plate 123 to provide a more uniform surface light source to the liquid crystal panel 110. Make it incident.

In the above-described liquid crystal display, the quantum dot 210 is 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 on the light guide plate 123 through the light incident surface of the light guide plate 123. Since the quantum dot 210 is implemented as white light having excellent optical characteristics, color reproducibility is improved compared to the conventional one. Thus, the color gamut of the liquid crystal display device of the present invention satisfies the color coordinate of BT.709.

In addition, since the quantum dot 210 is coated on the light-receiving surface of the light guide plate 123 and formed integrally with the light guide plate 123, the process for separately providing the quantum dot 210 can be eliminated, thereby improving the efficiency of the process. do.

In addition, since the quantum dots 210 do not have to be hardened to form a bar shape, it is possible to prevent the quantum dots hardened in the bar shape from being damaged.

FIG. 2 is a schematic cross-sectional view of a partial cross-section of FIG. 1, and FIG. 3 is a BT.709 on color coordinates of a liquid crystal display device having a backlight unit including a quantum dot plate according to a first embodiment of the present invention. This graph shows the overlap ratio.

As shown in FIG. 2, the reflective plate 125, the light guide plate 123 coated with the quantum dot 210 on the light incident surface, and the optical sheet 121 are stacked on the LED assembly 129 and the light guide plate 123. Thus, a backlight unit (120 of FIG. 1) is formed.

In addition, the liquid crystal panel 110 having a liquid crystal layer (not shown) interposed therebetween is disposed between the backlight unit 120 and the first and second substrates 112 and 114 therebetween. On each of the outer surfaces of the two substrates 112 and 114, polarizing plates 119a and 119b for selectively transmitting only specific light are attached.

The backlight unit (120 of FIG. 1) and the liquid crystal panel 110 are surrounded by an edge of the support main 130, and a cover bottom 150 formed of a horizontal surface 151 and a side surface 153 is coupled to the rear surface thereof. The top cover 140 covering the upper edge and the side of the liquid crystal panel 110 is coupled to the support main 130 and the cover bottom 150.

Here, the LED assembly 129 is located on one side of the light guide plate 123 to face the light incident surface coated with the quantum dot 210 of the light guide plate 123, the LED assembly 129 is a plurality of blue LED (129a) And, a plurality of blue LED (129a) includes a PCB (129b) that is mounted at a predetermined interval apart.

The LED assembly 129 is fixed in a position such as by bonding, 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 support main 130 is disposed at one side edge. The side surface of the protrusion 131 is formed to support the liquid crystal panel 110 on the upper surface of the LED assembly 129 is attached to the lower surface of the adhesive material (not shown) such as double-sided tape. And fixed.

This structure is called a side view type.

That is, in the LED assembly 129, 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 perpendicular to each other.

Here, although only one blue LED 129a of the LED assembly 129 is shown in the drawing, a plurality of blue LEDs 129a are mounted on the PCB 129b at a predetermined interval and receive driving power from the outside. do.

Here, the PCB 129b is an electronic circuit board that enables mounting and electrical connection of various electronic devices by printing a wiring pattern (not shown) on an insulating layer such as resin or ceramic. The PCB 129b is an epoxy-based FR4 PCB. Or a flexible printed circuit board (FPCB) or a metal core printed circuit board (MCPCB).

Recently, in order to quickly dissipate heat generated from the blue LEDs (129a), more and more MCPCBs are used. In this case, when the MCPCB is formed, 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 may be formed of a plastic material such as polymethylmethacrylate (PMMA) or polycarbonate (PC), which is an acrylic transparent resin, which is one of transparent materials capable of transmitting light. It is manufactured in a flat type.

The light guide plate 123 includes a pattern of a specific shape on the rear surface to supply a uniform surface light source. The pattern is an elliptical pattern, a polygonal shape, to guide light incident into the light guide plate 123. Patterns (polygon patterns), hologram patterns (hologram patterns) and the like can be configured in various ways.

In this case, the backlight unit (120 of FIG. 1) of the present invention is coated with a quantum dot 210 on the light incident surface of the light guide plate 123 facing the blue LED 129a emitting blue light.

That is, the quantum dot 210 is coated on the light incident surface of the light guide plate 123, and the quantum dot 210 is completely covered by the adhesive material 220, thereby being completely covered by the adhesive force of the adhesive material 220. The light guide plate 123 is fixed to the light incident surface.

In this case, the adhesive material 220 is preferably 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 incident 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 light emitted from the blue LED 129a.

Accordingly, the white light that is implemented 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 may be incident into the light guide plate 123 without losing light.

In addition, the quantum dot 210 is a state in which red light emitting nanoparticles and green light emitting nanoparticles are mixed, and the blue light emitted from the blue LED 129a is a quantum dot 210 in which red light emitting nanoparticles and green light emitting nanoparticles are mixed. In the process of passing through the white light having excellent optical properties.

Accordingly, white light having excellent optical characteristics is incident to the light guide plate 123, and the white light incident to the light guide plate 123 is spread evenly over a wide area of the light guide plate 123 while traveling inside the light guide plate 123 by several total reflections. It is to provide a surface light source of excellent white light to the liquid crystal panel 110.

Here, when the quantum dot 210 is described in more detail, the quantum dot 210 is a state in which light emitting nanoparticles are mixed, and the light emitting nanoparticles refer to particles having a predetermined size having a quantum confinement effect. Also called a quantum dot.

The light emitting nanoparticles are emitted by converting the wavelength of light injected from the light source into semiconductor nanocrystals of several nanometers (nm) size made through chemical synthesis process, and the emission wavelength is changed according to the size of the particles to emit all colors of visible light Can be.

The diameter of the light emitting nanoparticles is in the range of 1 to 10 nm.

Here, the light emitting nanoparticles may be a group II-VI, III-V or IV material, 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 material selected from the group consisting of CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe and HgS, and the shell is CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe and HgS It includes any one material selected from the group consisting of.

The light emitting nanoparticles can easily obtain 7 colors of rainbow colors including red, green, and blue depending on the size of light having various wavelengths according to the quantum dot size effect.

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

For example, in the case of using CdSe 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 the CdSe. When the diameter of CdSe is about 1.7 nm, it emits blue light, when it is 2.3 nm, it emits green light, and when it is 5.0 nm, it emits red light.

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

Accordingly, the backlight unit (120 of FIG. 1) of the present invention and the red light emitting nanoparticles on the light incident surface of the light guide plate 123 through which the blue light emitted from the blue LED (129a) to enter the light guide plate 123 is passed. By coating the quantum dot 210 mixed with the green light-emitting nanoparticles, the blue light emitted from the blue LED 129a realizes white light having excellent optical properties in the process of passing through the quantum dot 210, and the white light is a light guide plate. 123 is incident inside.

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

Therefore, the blue light emitted from the blue LED 129a, the red light implemented by the red light emitting nanoparticles, and the green light implemented by the green light emitting nanoparticles are mixed with each other, thereby realizing white light having excellent optical characteristics.

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

Therefore, the color coordinate 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 showing a BT.709 superposition ratio on a color coordinate of a liquid crystal display device having a backlight unit including a light guide plate coated with a quantum dot on a light incident surface according to an exemplary embodiment of the present invention.

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

As a result, the red (R) and the green (R) of the liquid crystal panel (110 of FIG. 2) through the white light implemented in the process of passing the blue light emitted from the blue LED (129a of FIG. G), it was found that the color gamut realized by transmitting the color filter layer (not shown) of the blue (B) color satisfactorily satisfied with the color coordinate of BT.709, which is the color coordinate system representing the color gamut of HDTV (High Definition Television). Can be.

Here, the color gamut refers to a range of colors that can be expressed by a display device including a liquid crystal display device, which measures color coordinates and luminance of red (R), green (G), and blue (B) states, respectively. Color Reproduction can be obtained for three primary colors.

Color coordinates are usually scientific quantities that measure colors and then display them to distinguish between them. The coordinates of red (700 nm), green (546.1 nm), and blue (435.8 nm) are measured by the International Commission on Illumination. on Illumination) is shown above the coordinate system specified in 1931.

To describe the color gamut in more detail, the color coordinates of red (R), green (G), and blue (B) determined on the color coordinates can be connected to calculate the area of the triangle, and the color gamut corresponds to the above area. It can be calculated by comparing with the area of NTSC (International Television Standards Committee) color coordinates.

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

Therefore, the BT.709 overlap ratio above means the amount overlapping the area of A on the color coordinate, and the area of A and the area of B overlap almost similarly.

As a result, the color reproducibility of the liquid crystal display device using white light as a light source implemented in the process of passing blue light emitted from the blue LED (129a of FIG. 2) of the present invention through the quantum dot (210 of FIG. 2) is high definition (HDTV). It is almost similar to the color coordinate of BT.709, which is the color coordinate system representing the color reproducibility of the television, indicating that the color reproducibility is improved.

In addition, the backlight unit (120 of FIG. 1) of the present invention is a quantum dot (210 of FIG. 2) is coated on the light-receiving surface of the light guide plate (123 of FIG. 2) is formed integrally with the light guide plate (123 of FIG. 2), The process for separately providing the dots 210 of FIG. 2 may be omitted.

That is, in order to provide a quantum dot (210 in FIG. 2) between the blue LED (129a in FIG. 2) and the light guide plate (123 in FIG. 2) in order to implement white light having excellent optical characteristics, After hardening the 210 to a bar shape, the cured bar-shaped quantum dots are adhered to the blue LED (129a in FIG. 2) and the light guide plate (123 in FIG. Although attached through a material (not shown), the present invention may eliminate all such processes.

At this time, since the bar-shaped cured quantum dots are made of a very thin thickness, the bar-cured quantum dots are formed into a blue LED (129a in FIG. 2) and the light guide plate (123 in FIG. 2). The process of attaching the light surface via an adhesive material (not shown) such as a double-sided tape is very difficult.

In particular, the bar-shaped cured quantum dots have low mechanical strength, and thus, when the bar-shaped cured quantum dots are formed in this bar shape, they may be easily damaged when an external impact is applied to the modular liquid crystal display.

Here, when breakage of the quantum dot hardened to a bar shape occurs, the blue light emitted from the blue LED (129a of FIG. 2) is not realized as a uniform white light, and some blue light is directly a light guide plate (123 of FIG. 2). Can be incident to.

Therefore, the blue light is mixed with red and green in the process of passing through a color filter (not shown) to realize red and green colors, and blue light is mixed in the color, and thus the image is realized. It will lower the color reproducibility of.

In addition, when breakage of the quantum dots hardened to a bar shape occurs, it is not possible to replace only the broken quantum dots, thereby causing a problem that the material cost increases.

Accordingly, the backlight unit (120 of FIG. 1) of the present invention coats the quantum dot (210 of FIG. 2) on the light incident surface of the light guide plate (123 of FIG. 2), thereby separately providing a quantum dot (210 of FIG. 2). Since the process can be deleted, the efficiency of the process can be improved, and the breakage of the quantum dots (210 of FIG. 2) can be prevented from occurring, thereby lowering the color reproducibility of the image or increasing the material cost. This can also be prevented.

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

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

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

In this case, the quantum dot 210 is coated on the light incident surface of the light guide plate 123 by a spin coating method or a bar coating method.

Next, as shown in FIG. 4B, the adhesive material 220 is coated on the light incident surface of the light guide plate 123 coated with the quantum dots 210.

The adhesive material 220 is characterized in that it has a property of being cured by a heating treatment or a thermal treatment.

At this time, the adhesive material 220 is a transparent polyacrylate resin (polyacrylates resin), epoxy resin (phenolic resin), phenolic resin (phenolic resin), polyamide resin (polyamides resin), polyimide resin ( polyimides rein), poly phenylenethers (poly phenylenethers resin), poly phenylene sulfides (poly phenylenesulfides resin) and the like. In particular, the polyimide resin or the polyamide resin adhesive material 220 has excellent adhesion performance.

The adhesive material 220 is made of a viscous material and is applied to completely cover the quantum dot 210 coated on the light incident surface of the light guide plate 123.

Next, as shown in FIG. 4C, by curing the adhesive material 220 coated to completely cover the quantum dot 210 through a heating process or a temperature reduction process, the quantum dot on the light incident surface according to the embodiment of the present invention. The light guide plate 123 coated with 210 is completed.

As described above, the liquid crystal display of the present invention has red light emitting nanoparticles and green light emitting light on the light incident surface of the light guide plate (123 of FIG. 4C) of the backlight unit 120 of FIG. 1 including a blue LED (129a of FIG. 2). By coating the quantum dot (210 in FIG. 4C) mixed with nanoparticles, the blue light emitted from the blue LED (129a in FIG. 2) is a quantum dot (210 in FIG. 4C) mixed with red light emitting nanoparticles and green light emitting nanoparticles. In the process of passing through the white light having excellent optical properties.

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

In addition, by coating the quantum dot (210 in FIG. 4C) on the light incident surface of the light guide plate (123 in FIG. 4C), the process for separately providing the quantum dot (210 in FIG. 4C) can be eliminated, thereby improving the efficiency of the process. In addition, it is possible to prevent the breakage of the quantum dot (210 of FIG. 4C) to occur, thereby reducing the color reproducibility of the image or increasing the material cost.

Meanwhile, in the above-described structure, the light source LED (129a in FIG. 2) is a blue LED emitting blue light, and the quantum dot (210 in FIG. 4C) coated on the light incident surface of the light guide plate 123 of FIG. As an example, a structure in which red light emitting nanoparticles and green light emitting nanoparticles are mixed is described as an example. In this case, the quantum dot 210 may be formed of yellow light emitting nanoparticles having a quantum confinement effect. The LED (129a in FIG. 2) may be a red and green or UV LED, wherein the quantum dots (210 in FIG. 4C) are mixed with light emitted from the LED (129a in FIG. 2) to emit white light. It may comprise nanoparticles.

 For example, when the LED (129a of FIG. 2) is a UV LED, the quantum dot (210 of FIG. 4c) coated on the light incident surface of the light guide plate (123 of FIG. 4c) is cured by mixing red, green, and blue light emitting nanoparticles. It can be made of a structure.

In addition, the backlight unit (120 of FIG. 1) having the above-described structure is generally called a side light method, and a plurality of blue LEDs (129a of FIG. 2) are mounted on the PCB (129b of FIG. 2) according to the purpose. It can be arranged in dog layers.

In addition, it is also possible to include a plurality of sets of the LED assembly (129 of FIG. 2) to correspond to each other along both side edge portions of the cover bottom (150 of FIG. 2) facing each other.

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

110: liquid crystal panels 112 and 114: first and second substrates
119a and 119b: first and second polarizing plates
120: backlight unit, 121: optical sheet, 123: light guide plate, 125: reflector, 129: LED assembly (129a: blue LED, 129b: PCB)
130: support main, 131: protrusion, 140: top cover, 150: cover bottom
210: quantum dot, 220: adhesive material

Claims (9)

A reflector;
A light guide plate mounted on the reflective plate and coated with a quantum dot on a light incident surface;
An LED assembly arranged along a light incident surface of the light guide plate, the LED assembly including a plurality of LEDs emitting light toward the light incident surface, and a PCB on which the plurality of LEDs are mounted;
An optical sheet seated on the light guide plate;
A liquid crystal panel mounted on the plurality of optical sheets;
A support main covering the edge of the liquid crystal panel;
Cover bottom consisting of the bottom and the side that is in close contact with the support main back
And a quantum dot to excite the light emitted from the plurality of LEDs to implement white light.
The method of claim 1,
And the quantum dot is fixed to the light incident surface of the light guide plate through an adhesive material, and the adhesive material completely surrounds the quantum dot.
The method of claim 2,
The adhesive material is a transparent liquid crystal display device.
The method of claim 2,
One side of the adhesive material is in contact with the light incident surface of the quantum dot and the light guide plate, and the other side of the contacting material is in contact with one surface from which the light of the LED is emitted.
The method of claim 2,
The adhesive material is cured after a predetermined time.
The method of claim 1,
The LED is a blue LED that emits blue light, the quantum dot is a liquid crystal display device is a mixture of red light emitting nanoparticles and green light emitting nanoparticles having a quantum confinement effect (mixed effect).
The method of claim 1,
Wherein the LED is a blue LED emitting blue light, and the quantum dot is a yellow light emitting nanoparticle having a quantum confinement effect.
The method of claim 1,
Wherein the red light emitting nanoparticles, the green light emitting nanoparticles, and the yellow light emitting nanoparticles are selected from one of CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe, or HgS.
The method of claim 1,
The red light emitting nanoparticles, the green light emitting nanoparticles, and the yellow light emitting nanoparticles are CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe, and a core including any material selected from the group consisting of CdSe, CdTe, A liquid crystal display device having a core-shell structure consisting of a shell of any one material selected from the group consisting of CdS, ZnSe, ZnTe, ZnS, HgTe, and HgS.

Images