KR101742625B1 - 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 that a quantum dot plate is cured by mixing red light emitting nano particles and green light emitting nano particles in front of a blue LED through which blue light is emitted.
Thus, it is possible to realize white light having excellent optical characteristics, thereby improving the color reproduction rate, and thus the color coordinate of BT.709 is satisfied.
By providing a quantum dot plate corresponding to the size of each LED, the material cost can be reduced as compared with a case where the LED has a long bar shape corresponding to the PCB of the LED assembly. bar shape can be prevented from being damaged.

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 device, and more particularly to an improvement in the 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 29a used as a light source of the liquid crystal display device is composed of a light emitting LED chip 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, the color reproduction rate realized by transmitting the white light emitted from the blue LED to the red (R), green (G), and blue (B) color filter patterns of the liquid crystal panel 10 is low, The color coordinates of BT.709, which is the color coordinate system indicating the color reproduction ratio of the high definition television (HDTV), is not satisfied.

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; 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; A plurality of quantum dot plates interposed between each of the plurality of LEDs and the light incident surface of the light guide plate, the quantum dot plate corresponding to the size of each of the plurality of LEDs; 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, wherein the quantum dot plate excites light emitted from the plurality of LEDs to realize white light.

The quantum dot plate has a first surface attached to one side of the LED through which the light is emitted through a first adhesive material and a second side of the quantum dot plate opposite to the first surface is attached to the light- And the second adhesive material, and the first and second adhesive materials are transparent.

In addition, the LED is a blue LED that emits blue light, and the quantum dot plate is cured by mixing a red light emitting nano particle and a green light emitting nano particle having a quantum confinement effect, and the LED emits blue light Blue LED, and the quantum dot plate is cured by the yellow light emitting nanoparticles having a quantum confinement effect.

The red light emitting nanoparticles, the green light emitting nanoparticles and the yellow light emitting nanoparticles may be CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, InP, GaP, GaInP2, PbS, ZnO, TiO2, AgI, AgBr, Hg12, CdSe, CdSe, CdS, ZnSe, ZnTe, ZnS, HgTe, and HgSe are selected from the group consisting of PbSe, In2S3, In2Se3, Cd3P2, Cd3As2, and GaAs, and the red light emitting nano particles, the green light emitting nano particles, Shell and a shell of any one material selected from the group consisting of CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe, and HgS as a core-shell structure.

The LED assembly is located such that the PCB faces the light incident surface of the light guide plate, and the PCB is positioned perpendicular to the light incident surface of the light guide plate.

As described above, the present invention has a quantum dot plate cured by mixing red light emitting nano particles and green light emitting nano particles in front of a blue LED emitting blue light, Thus, it is possible to improve the color reproduction rate, and thus the color coordinates of BT.709 can be satisfied.

In addition, since the quantum dot plate is provided so as to correspond to the size of each LED, the material cost can be reduced as compared with the case where the quantum dot plate is formed in a long bar shape corresponding to the PCB of the LED assembly.

In addition, there is an effect that it is possible to prevent a long bar-shaped quantum dot plate from being broken.

1 is an exploded perspective view of a liquid crystal display device according to a first embodiment of the present invention;
FIG. 2 is a perspective view schematically showing a part of an assembled state of the LED assembly and the light guide plate according to the first embodiment of the present invention. FIG.
3 is a graph showing a BT.709 overlap ratio 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.
FIGS. 4A and 4B are simulation photographs comparing the appearance of a case where the quantum dot plate is formed to correspond to the size of the blue LED and a case where the quantum dot plate is formed into a long bar shape corresponding to the PCB of the LED assembly.
Fig. 5 is a cross-sectional view schematically showing a partial cross-section of the modular Fig. 1; Fig.
6 is a cross-sectional view schematically showing a partial cross section of a modularized liquid crystal display device according to a second embodiment of the present invention.

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 a first 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 is a part that 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 quantum dot plate 200, a white or silver reflection plate 125, a light guide plate 123 mounted on the reflection 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.

The LED assembly 129 is of a top view type in which light emitted from the plurality of LEDs 129a is perpendicular to the PCB 129b.

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.

The backlight unit 120 of the present invention is characterized in that a quantum dot plate 200 having a size corresponding to the blue LED 129a is provided in front of each of the blue LEDs 129a to which blue light is emitted .

Accordingly, the backlight unit 120 of the present invention realizes white light having excellent optical characteristics. Thus, the color reproduction rate is improved even though the blue LED 129a having a low color reproduction rate is used as the light source of the backlight unit 120. [

The quantum dot plate 200 is provided so as to correspond to the size of each blue LED 129a and is provided in front of each of the blue LEDs 129a so as to correspond to the PCB 129b of the LED assembly 129 The material cost can be reduced as compared with the case of a long bar shape.

In addition, it is possible to prevent a problem that the quantum dot plate 200 is broken. Let me take a closer look at this later.

When the blue light emitted from the plurality of blue LEDs 129a passes through the quantum dot plate 200 and is realized as excellent white light, the white light is incident into the light guide plate 123, The liquid crystal panel 110 is uniformly distributed over a wide area of the light guide plate 123 to provide a planar light source.

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 liquid crystal panel 110 and the backlight unit 120 are modularized through a top cover 140, a support main 130 and a cover bottom 150. The top cover 140 is disposed on the upper surface and the side surface of the liquid crystal panel 110, The top cover 140 is opened so that an image formed on the liquid crystal panel 110 is displayed.

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 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.

In the above-described liquid crystal display device, the quantum dot plate 200 is positioned in front of the blue LED 129a, thereby realizing white light having excellent optical characteristics, thereby improving the color gamut. Thus, the color reproduction ratio of the liquid crystal cell of the present invention satisfies the color coordinates of BT.709.

The quantum dot plate 200 is provided so as to correspond to the size of each blue LED 129a and is provided in front of each of the blue LEDs 129a so as to correspond to the PCB 129b of the LED assembly 129 The material cost can be reduced as compared with the case of a long bar shape. In addition, it is possible to prevent a problem that the quantum dot plate 200 is broken.

In addition, by providing the quantum dot plate 200 corresponding to the size of the blue LED 129a, it is possible to replace only the damaged quantum dot plate 200 when the quantum dot plate 200 is broken, Shape, the entire quantum dot plate 200 needs to be replaced, so that the material cost can be reduced.

FIG. 2 is a perspective view schematically showing a part of an assembled state of the LED assembly and the light guide plate according to the first embodiment of the present invention. FIG. 3 is a plan view of the backlight including the quantum dot plate according to the first embodiment of the present invention. 709 overlap ratio on the chromaticity coordinates of the liquid crystal display provided with the unit.

2, an LED assembly 129 including a blue LED 129a and a PCB 129b is attached and fixed to one edge of the cover bottom 150, and a reflector (not shown) The light guide plate 123 is mounted on the reflection plate 125 of FIG. 1 in a direction in which blue light is emitted from the blue LED 129a of the LED assembly 129, The light incident surface of the light guide plate 123 is correspondingly positioned.

The light guide plate 123 may be formed of a plastic material such as polymethylmethacrylate (PMMA), which is one of transparent materials that can transmit light, or a polycarbonate (PC) (flat type).

The light guide plate 123 includes a pattern of a specific pattern on its back surface in order 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.

A quantum dot plate 200 is interposed between the blue LED 129a and the light guide plate 123. The quantum dot plate 200 is formed in the same size as each blue LED 129a of the LED assembly 129 And attached to the light entrance surface of each of the blue LED 129a and the light guide plate 123 via adhesive materials 210a and 210b such as a double-sided tape.

That is, one surface of the quantum dot plate 200 is attached to the front side of the blue LED 129a through which the blue light is emitted through the first adhesive material 210a, and the other surface of the quantum dot plate 200 is attached to the second adhesive material And is attached to the light incoming surface of the light guide plate 123 through the light guide plate 210b.

Accordingly, the white light realized as the blue light emitted from the blue LED 129a passes through the quantum dot plate 200 can be incident into the light guide plate 123 without any loss of light.

At this time, the adhesive materials 210a and 210b are preferably transparent adhesive materials.

In the quantum dot plate 200, the red light emitting nano particles and the green light emitting nano particles are mixed and cured, and the blue light emitted from the blue LED 129a is the quantum dots mixed with the red light emitting nano particles and the green light emitting nano particles. The white light having excellent optical characteristics is realized in the process of passing through the plate 200.

The white light having excellent optical characteristics is incident on the light guide plate 123 and the white light incident into the light guide plate 123 is guided to the wide area of the light guide plate 123 And the surface light source of excellent white light is provided to the liquid crystal panel (110 of FIG. 1) by spreading evenly.

Here, the quantum dot plate 200 may include a quantum dot plate 200 in which light emitting nano particles are mixed and cured, and the light emitting nano particles have a predetermined size particle having a quantum confinement effect , Which is also referred to as 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 depending on 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 includes the quantum dot plate 200 cured by mixing the red light emitting nano particles and the green light emitting nano particles in front of the blue LED 129a, The blue light emitted from the light source 200 emits white light having excellent optical characteristics in the process of passing through the quantum dot plate 200.

That is, when the blue light is emitted from the blue LED 129a, the blue light is converted into the red light by converting the wavelength of the blue light by the red light emitting nanoparticles of the quantum dot plate 200 in the course of passing through the quantum dot plate 200 , The wavelength of the blue light is converted by the green 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.

Therefore, 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), the backlight unit 120 of FIG. 1 of the present invention is not limited to the blue LED 129a and the quantum dot plate 200 The color reproduction rate realized by transmitting the white light realized by the red (R), green (G), and blue (B) color filters of the liquid crystal panel (110 of FIG. 1) is improved.

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 showing a BT.709 overlap ratio on a color coordinate system of a liquid crystal display device having a backlight unit including the quantum dot plate according to the first embodiment of the present invention.

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

2) of the liquid crystal panel (110 in FIG. 1) of the quantum dot plate (200 in FIG. 2) through blue light emitted from the blue LED (129a in FIG. 2) G and B colors, 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 HDTV (High Definition Television), is implemented with an area of A, The liquid crystal display device in which white light is realized in the process of passing blue light through the quantum dot plate (200 in FIG. 2) is realized as the area of B.

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.

2) of the liquid crystal panel (110 in FIG. 2) is transmitted to the liquid crystal panel (R in FIG. 1) through the quantum dot plate (200 in FIG. 2) The color reproduction ratio realized by transmitting the color filter layers of green (G), and blue (B) is substantially similar to the color coordinates of BT.709, which is the color coordinate system representing the color reproduction ratio of HDTV (High Definition Television) This shows that the color reproduction rate is further improved.

2) is provided so as to correspond to the size of each blue LED (129a in Fig. 2), and is provided in front of each blue LED (129a in Fig. 2), so that the LED assembly The material cost can be reduced as compared with the case of a long bar shape corresponding to the PCB 129 of FIG. 2 (129).

In addition, since the quantum dot plate (200 in FIG. 2) has a low mechanical strength, when it is formed into a long bar shape, it can be easily broken when an external impact is applied to a modularized liquid crystal display device. However, And the quantum dot plate (200 in FIG. 2) are provided so as to correspond to the size of the LED, thereby preventing such a problem from occurring.

Here, when the quantum dot plate (200 in FIG. 2) is damaged, the 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 Can be entered.

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, by providing the quantum dot plate 200 corresponding to the size of the blue LED 129a, it is possible to replace only the damaged quantum dot plate 200 when the quantum dot plate 200 is broken, Shape, the entire quantum dot plate 200 needs to be replaced, so that the material cost can be reduced.

FIGS. 4A and 4B are simulation photographs comparing a case where the quantum dot plate is formed to correspond to the size of the blue LED and a case where the quantum dot plate is formed into a long bar shape corresponding to the PCB of the LED assembly.

4A shows a state in which the liquid crystal display device is driven in the case where the quantum dot plate 200 (FIG. 2) is formed into a long bar shape corresponding to the PCB (129b in FIG. 2) of the LED assembly (FIG. 2) is formed to correspond to the size of the blue LED (129a in FIG. 2) according to the first embodiment of the present invention, and the quantum dot plate 200 are placed in the first half of the blue LED (129a in Fig. 2), respectively.

Referring to FIGS. 4A and 4B, when the quantum dot plate 200 (FIG. 2) is formed to have a long bar shape and the blue LED (129a of FIG. 2) .

Accordingly, by forming the quantum dot plate (200 in FIG. 2) to correspond to the size of the blue LED (129a in FIG. 2), the material cost can be reduced as compared with the case of a long bar shape, It is desirable to prevent the problem that the plate (200 in Fig. 2) is broken.

Fig. 5 is a cross-sectional view schematically showing a partial cross-section of the modular Fig.

As shown in the drawing, the LED assembly 129 including the reflection plate 125, the light guide plate 123, the PCB 129b on which the blue LED 129a and the blue LED 129a are mounted, The sheets 121 are laminated to form 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.

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 an 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).

Here, the backlight unit 120 of FIG. 1 includes the quantum dot plate 200 between the blue LED 129a and the light incident surface of the light guide plate 123 through the first and second adhesive materials 210a and 210b. The blue light emitted from the blue LED 129a is realized as white light having excellent optical characteristics in the course of passing through the quantum dot plate 200. The white light having such excellent optical characteristics is transmitted through the light incoming surface of the light guide plate 123, (123).

The white light incident into the light guide plate 123 spreads evenly over a wide area of the light guide plate 123 by total reflection several times in the light guide plate 123 and is emitted toward the liquid crystal panel 110. In the course of passing through the optical sheet 121 So that the liquid crystal panel 110 is provided with white light of a surface light source having excellent optical characteristics.

6 is a cross-sectional view schematically showing a partial cross section of a modular liquid crystal display device according to a second embodiment of the present invention.

In order to avoid redundant explanations, the same parts as those of the first embodiment described above are denoted by the same reference numerals, and only the characteristic contents described above in the second embodiment will be described.

As shown in the drawing, the LED assembly 129 including the reflection plate 125, the light guide plate 123, the PCB 129b on which the blue LED 129a and the blue LED 129a are mounted, The sheets 121 are laminated to form 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.

At this time, the LED assembly 129 is fixed to the horizontal surface 151 of the cover bottom 150 by a method such as adhesion, and the blue LED 129a mounted on the PCB 129b Blue light is emitted parallel to the PCB 129b and is incident into the light guide plate 123 through the light entrance surface of the light guide plate 123. [

That is, the light incident surfaces of the PCB 129b and the light guide plate 123 are positioned perpendicular to each other. The light guide plate 123 has a first thickness t1 and the light emitting surface of the LED 129a has a second thickness t2 equal to the first thickness t1 and the PCB 129b has a light emitting surface And has a width w larger than the second thickness t2 in a direction perpendicular to the plane. In this case, when the PCB 129b is arranged in parallel to the light-incoming surface of the light guide plate 123, the PCB 129b protrudes from the light guide plate 123, so that the thickness of the liquid crystal display device is inevitably increased. However, in the present invention, when the PCB 129b is disposed perpendicularly to the light-incoming surface of the light guide plate 123 as shown in FIG. 6, it is possible to prevent an increase in thickness of the liquid crystal display device caused by the PCB 129b. 6, one end of the PCB 129b is disposed below the light guide plate 123 so as to overlap with the light guide plate 123, thereby preventing a problem of an increase in the width of the liquid crystal display device due to the PCB 129b.

This structure is referred to as a side view type.

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 backlight unit 120 of FIG. 1 includes the quantum dot plate 200 between the blue LED 129a and the light incident surface of the light guide plate 123 through the first and second adhesive materials 210a and 210b. The blue light emitted from the blue LED 129a is realized as white light having excellent optical characteristics in the process of passing through the quantum dot plate 200. White light having such excellent optical characteristics is transmitted through the light incoming surface of the light guide plate 123, (123).

The white light incident into the light guide plate 123 spreads evenly over a wide area of the light guide plate 123 by total reflection several times in the light guide plate 123 and is emitted toward the liquid crystal panel 110. In the course of passing through the optical sheet 121 So that the liquid crystal panel 110 is provided with white light of a surface light source having excellent optical characteristics.

As described above, the liquid crystal display device of the present invention includes the quantum dot plate 200 which is cured by mixing the red light emitting nano particles and the green light emitting nano particles in front of the blue LED 129a from which the blue light is emitted, The blue light emitted from the light emitting layer 129a passes through the quantum dot plate 200 in which the red light emitting nano particles and the green light emitting nano particles are mixed, thereby realizing white light having excellent optical characteristics.

Therefore, 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), the backlight unit 120 of FIG. 1 of the present invention is not limited to the blue LED 129a and the quantum dot plate 200 The color reproduction rate realized when the white light realized by the liquid crystal panel 110 is transmitted through the color filter layers (not shown) of the red (R), green (G) and blue (B) colors of the liquid crystal panel 110 is improved. Thus, 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.

The quantum dot plate 200 is provided so as to correspond to the size of each blue LED 129a and is provided in front of each of the blue LEDs 129a so as to correspond to the PCB 129b of the LED assembly 129 The material cost can be reduced as compared with the case of a long bar shape.

In addition, since the quantum dot plate 200 has a low mechanical strength, it can be easily broken when an external impact is applied to a modularized liquid crystal display device in the case of a long bar shape. However, as described above, By providing the plate 200 corresponding to the size of the blue LED 129a, such a problem can be prevented from occurring.

Meanwhile, in the above-described structure, the LED 129a as a light source is a blue LED that emits blue light. At this time, the Quantum dot plate 200 has a structure in which red light emitting nano particles and green light emitting nano particles are mixed and cured, In this case, the quantum dot plate 200 may be made of yellow light emitting nanoparticles having a quantum confinement effect, or the LED 129a may be a red and green or UV LED, Emitting nanoparticles can be mixed with light emitted from the LED 129a to emit white light.

 For example, when the LED 129a is a UV LED, the quantum dot plate 200 may have a structure in which red, green, and blue light emitting nanoparticles are mixed and cured.

The backlight unit 120 of the above-described structure (120 in FIG. 1) is generally called a side light system, and a plurality of LEDs 129a may be arranged in a multi-layer structure on the PCB 129b .

Further, it is also possible to provide a plurality of LED assemblies 129 each in a corresponding manner so as to interpose the cover bottoms 150 along opposite side edges facing each other.

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.

123: light guide plate
129: LED assembly (129a: blue LED, 129b: PCB)
150: cover bolt
200: Quantum dot plate
210a, 210b: first and second adhesive materials

Claims (9)

A reflector;
A light guide plate which is seated on the reflection plate and has a first thickness;
An LED assembly including a plurality of LEDs arranged along the light incident surface of the light guide plate and having a light emitting surface through which light is emitted toward the light incident surface, and a PCB on which the plurality of LEDs are mounted so as to be spaced apart from each other;
A plurality of quantum dot plates each corresponding to each of the plurality of LEDs and having the same size as each of the plurality of LEDs, the quantum dot plate interposed between the plurality of LEDs and the light incident surface of the light guide plate;
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 connected to the bottom surface, wherein the quantum dot plate excites light emitted from the plurality of LEDs to emit white light,
Wherein the light emitting surface has a second thickness equal to the first thickness and the PCB has a width greater than the second thickness in a direction perpendicular to the light emitting surface,
Wherein the LED assembly is disposed such that the PCB is vertically positioned with respect to the light incident surface of the light guide plate, and one end of the PCB overlaps the light guide plate under the light guide plate.
The method according to claim 1,
Wherein the quantum dot plate has a first surface attached to one side of the LED through which the light is emitted through a first adhesive material and a second side of the quantum dot plate opposite to the first surface is attached to the light- And the second adhesive material.
3. The method of claim 2,
Wherein the first and second adhesive materials are transparent.
The method according to claim 1,
Wherein the LED is a blue LED that emits blue light, and the quantum dot plate is cured by mixing 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 plate is a cured yellow light emitting nanoparticle having a quantum confinement effect.
5. The method according to one of claims 4 and 5,
The light emitting nanoparticles may be made of one selected from the group consisting of CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, InP, GaP, GaInP2, PbS, ZnO, TiO2, AgI, AgBr, Hg12, PbSe, In2S3, In2Se3, Cd3P2, Cd3As2, Liquid crystal display device.
5. The method according to one of claims 4 and 5,
Wherein the light emitting nanoparticles are made of a material selected from the group consisting of CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe and HgS, Wherein the core is a core-shell composed of a shell of a material selected from the group.
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