KR20120066322A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: A liquid crystal display device is provided to prevent yellow color sense fault of a light guide plate and increase brightness and color reproduction. CONSTITUTION: A quantum dot plate(127) of a bar shape is arranged. A plurality of optical sheets(121) is settled on a light guide plate. A liquid crystal panel(110) is settled on a plurality of the optical sheets. A support main(130) covers the liquid crystal panel. A cover bottom(150) is composed of a bottom of the support main.

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 color gamut of a liquid crystal display device 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 (29a) used as a light source of the liquid crystal display device is composed of a light emitting LED chip and a phosphor, 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, since the white light emitted from the blue LED penetrates the color filter patterns of the red (R), green (G), and blue (B) colors of the liquid crystal panel 10, the color reproducibility is low. It does not satisfy the color coordinate of BT.709, which is the color coordinate system representing the color reproduction rate of High Definition Television.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first 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 addition, a second object of the present invention is to prevent the yellow color defect from occurring in the light guide plate incident portion.

In order to achieve the object as described above, the present invention is a reflection plate; A light guide plate mounted on an upper portion of the reflective plate; LEDs including a plurality of blue LEDs arranged along a light incidence surface of the light guide plate, the plurality of blue LEDs emitting light toward the light incidence surface, and a plurality of blue LEDs mounted thereon and a blue ink layer formed on one surface facing the light guide plate. An assembly; A quantum dot plate having a bar shape interposed between the plurality of blue LEDs and a light incident surface of the light guide plate; 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; And a cover bottom including a bottom surface and a side surface thereof which are in close contact with the support main back surface, wherein the bar-shaped quantum dot plate is configured to excite the light emitted from the plurality of blue LEDs to implement white light. To provide.

In this case, the PCB is a bar (bar) shape, the plurality of blue LEDs are arranged at regular intervals so as to emit light toward the other edge of the PCB along one longitudinal side of the PCB, the blue ink layer Is formed on the other edge side of the PCB, the PCB is positioned perpendicular to the light incident surface of the light guide plate, and the other edge side of the PCB on which the blue ink layer is formed covers a part of the light incident part of the light guide plate.

The bar shaped quantum dot plate is cured by mixing red light emitting nano particles and green light emitting nano particles having a quantum confinement effect, and the bar shaped quantum dot plate is a quantum dot plate. Yellow light emitting nanoparticles having a quantum confinement effect are cured.

At this time, the light emitting nanoparticles are selected from among CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, InP, GaP, GaInP2, PbS, ZnO, TiO2, AgI, AgBr, Hg12, PbSe, In2S3, In2Se3, Cd3P2, Cd3As2 or GaAs2 The light-emitting nanoparticles are made of one core and any one material selected from the group consisting of CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe and HgS, and 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, the present invention provides a white light having excellent optical characteristics by providing a quantum dot plate in which red light emitting nanoparticles and green light emitting nanoparticles are mixed and cured in front of a blue LED emitting blue light. It can be implemented, thereby improving the color reproducibility, which has the effect of satisfying the color coordinates of BT.709.

In addition, since a plurality of blue LEDs are mounted and a blue ink layer is formed on one surface of the PCB covering the light guide plate incident part, yellow color defect of the light guide plate incident part may be prevented from occurring.

1 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.
2 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 quantum dot plate according to an exemplary embodiment of the present invention.
Figure 3a is a perspective view schematically showing the structure of an LED assembly according to an embodiment of the present invention.
3B is a top view of FIG. 3A.
Figure 4 is a photograph showing the appearance of a bad yellow color.
FIG. 5 is a schematic cross-sectional view of a partial cross section of FIG. 1 modularized; FIG.

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

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.

A polarizer (not shown) for selectively transmitting only specific light is 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 quantum dot plate 127, a white or silver reflector 125, a light guide plate 123 seated on the reflector 125, and an upper portion thereof. It includes an optical sheet 121 is interposed.

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 128 and a plurality of LEDs 128 at regular intervals. It includes a PCB 200 that is mounted spaced apart.

The LED assembly 129 has a side view type in which light emitted from the plurality of LEDs 128 is parallel to the PCB 200.

At this time, the blue ink layer 210 (see FIG. 3A) for guiding light emitted from the LED 128 is formed on the PCB 200 on which the LED 128 is mounted.

That is, the blue ink layer 210 (refer to FIG. 3A) reflects the light emitted from the LED 128 toward the upper direction of the LED 128 to the inside of the light guide plate 123, and the blue ink layer ( 210, see FIG. 3A), is formed by coating the blue ink using a silk screen technique.

In addition, the LED 128 mounted on the PCB 200 includes a blue LED emitting blue light having a wavelength of about 430 nm to 450 nm to improve luminous efficiency and brightness.

In addition, the backlight unit 120 of the present invention includes a bar-shaped quantum dot plate 127 in front of the blue LED 128 from which blue light is emitted from the blue LED 128. It is done.

The bar-shaped quantum dot plate 127 may correspond to the length of the PCB 200 of the LED assembly 129, and the width may correspond to the light incident surface of the light guide plate 123.

Therefore, the backlight unit 120 of the present invention implements white light having excellent optical characteristics. Accordingly, the backlight unit 120 of the present invention improves the color reproduction rate even when the blue LED 128 having the low color reproduction rate is used as the light source of the backlight unit 120.

As such, when the blue light emitted from the plurality of blue LEDs 128 passes through the quantum dot plate 127 and is implemented as excellent white light, the white light is incident into the light guide plate 123, and the light is incident on the total reflection inside the light guide plate 123. As a result, the surface of the light guide plate 123 is evenly spread to provide the surface light source to the liquid crystal panel 110.

The light guide plate 123 may be formed of a plastic material such as polymethylmethacrylate (PMMA), which is one of transparent materials capable of transmitting light, or polycarbonate (PC). 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 addition, the reflector 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.

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 the top and side surfaces of the liquid crystal panel 110. A rectangular frame having a cross section bent in a shape of “a” so as to cover an edge thereof is configured to open an entire surface of the top cover 140 to display an image implemented in the liquid crystal panel 110.

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 the above-described liquid crystal display, the bar-shaped quantum dot plate 127 is positioned in front of the blue LED 128 to realize white light having excellent optical characteristics, thereby improving color reproducibility. Thus, the color gamut of the liquid crystal display device of the present invention satisfies the color coordinate of BT.709.

In addition, the backlight unit 120 of the present invention forms a blue ink layer 210 (refer to FIG. 3A) for guiding light emitted from the blue LED 128 on the PCB 200 to thereby receive the light guide plate 123. Correspondingly, light leakage may be prevented from occurring, and the light intensity incident to the light guide plate 123 may be increased, thereby improving light efficiency.

In particular, it is possible to prevent a yellow color defect from occurring in response to the light incident portion of the light guide plate 123 through the blue ink layer 210 (refer to FIG. 3A).

Here, when looking at the bar-shaped quantum dot plate 200 in more detail, the quantum dot plate 200 is a state in which the light-emitting nanoparticles are mixed and cured, the light-emitting nanoparticles quantum confinement effect (quantum confinement effect) It refers to a particle having a predetermined size, which is also called a quantum dot (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.

The light emitting nanoparticles may be a 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 the present invention includes a bar-shaped quantum dot plate 127 in which a red light emitting nanoparticle and a green light emitting nanoparticle are mixed and cured in front of the blue LED 128 to thereby be blue. The blue light emitted from the LED 128 may implement white light having excellent optical characteristics in the course of passing through the bar-shaped quantum dot plate 127.

That is, when blue light is emitted from the blue LED 128, the blue light passes through the bar-shaped quantum dot plate 127, and the red light emitting nanoparticles of the bar-shaped quantum dot plate 127 The wavelength of the blue light is converted into the red light by the blue light, and the wavelength of the blue light is converted into the green light by the green light emitting nanoparticles.

Therefore, the blue light emitted from the blue LED 128 and the red light embodied by the red light emitting nanoparticles and the green light embodied by the green light emitting nanoparticles are mixed with each other, thereby realizing white light having excellent optical characteristics.

FIG. 2 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 bar-shaped quantum dot plate 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 white light implemented in the process of passing the blue light emitted from the blue LED (128 in FIG. 1) through the bar-shaped quantum dot plate (127 in FIG. 1) is applied to the liquid crystal panel (110 in FIG. 1). The color reproducibility achieved by passing through the color filter layers of (R), green (G), and blue (B) colors satisfies the color coordinates of BT.709, the color coordinate system representing the color reproduction ratio of HDTV (High Definition Television). I can see that.

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.

Therefore, 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, blue light emitted from the blue LED (128 in FIG. 1) according to the embodiment of the present invention is A liquid crystal display device in which white light implemented in a process of passing through a bar-shaped quantum dot plate 127 of FIG. 1 is realized with an 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 white light implemented in the process of passing the blue light emitted from the blue LED (128 of FIG. 1) of the present invention through the bar-shaped quantum dot plate (127 of FIG. 1) is formed in the liquid crystal panel (110 of FIG. 1). The color reproducibility achieved by passing through the red (R), green (G), and blue (B) color filter layers is almost identical to that of BT.709, a color coordinate system representing the color reproducibility of HDTV (High Definition Television). Similar satisfaction is obtained, which indicates that color reproducibility is further improved.

In addition, the backlight unit 120 of FIG. 1 forms a blue ink layer 210 (see FIG. 3A) for guiding light emitted from a blue LED (128 of FIG. 1) on a PCB (200 of FIG. 1). As a result, light leakage phenomenon may be prevented from occurring in response to the light incident part of the light guide plate 123, and the light efficiency incident to the light guide plate 123 may be increased, thereby improving light efficiency.

In particular, it is possible to prevent a yellow color defect from occurring in response to the light incident portion of the light guide plate 123 through the blue ink layer 210 (refer to FIG. 3A).

3A is a perspective view schematically illustrating a structure of an LED assembly according to an exemplary embodiment of the present invention, and FIG. 3B is a plan view of FIG. 3A.

4 is a photograph showing a state in which yellow color defects are generated.

As shown in FIGS. 3A to 3B, the LED assembly 129 is mounted by surface mount technology (SMT) with a plurality of blue LEDs 128 and a plurality of blue LEDs 128 spaced apart at regular intervals. It includes a PCB 200.

Here, the PCB 200 is composed of a power wiring layer 205, an insulating layer 203 and a PCB base 201 on which metal wiring (not shown) is formed. The PCB base 201 is a power wiring layer 205 and an insulating layer. 203 and other components are mounted on and supported by the upper layer, and the heat generated from the plurality of blue LEDs 128 is discharged to the bottom side.

The PCB base 201 may be formed of a metal having high thermal conductivity such as aluminum (Al) or copper (Cu), or may be coated with a heat transfer material to improve a heat dissipation function.

Alternatively, a heat sink (not shown) such as a heat sink may be provided on the rear surface of the PCB base 201 to receive heat from each of the blue LEDs 128 and to be more efficiently discharged to the outside.

A power wiring layer 205 including a plurality of metal wirings (not shown) formed by patterning a conductive material is formed on the PCB base 201, and is insulated between the PCB base 201 and the power wiring layer 205. A layer 203 is positioned to electrically insulate the PCB base 201 from the metallization (not shown).

The plurality of LEDs 128 mounted on the PCB 200 are connected in parallel through a metal wiring (not shown) of the power wiring layer 205 to receive power.

In this case, the plurality of LEDs 128 are controlled on / off by an LED driving circuit (not shown), the LED driving circuit (not shown) is in close contact with the cover cover (150 in FIG. 1). Therefore, the overall size of the liquid crystal display device is minimized.

The plurality of LEDs 128 are connected to the LED driving circuit (not shown) in a state connected to each other, the flexible cable 220 is connected to one side on the PCB 200, LED driving circuit (not shown) and Connected.

In this case, the PCB 200 is divided into a region (hereinafter referred to as A region) in which the blue LED 128 is mounted and a region (hereinafter referred to as B region) for guiding light emitted from the blue LED 128. That is, the plurality of blue LEDs 128 are mounted at a predetermined interval adjacent to one edge side of the PCB 200, where each blue LED 128 emits light toward the other edge facing one edge. To be mounted on the PCB 200.

The blue ink layer 210 is formed at the other edge side of the PCB 200 to guide the light emitted from the blue LED 128.

The blue ink layer 210 is formed by coating an ink including a blue pigment using a silk screen technique.

At this time, the other edge of the PCB 200 on which the blue ink layer 210 is formed is located near the light incident portion of the light guide plate 123 of FIG. 1, so that the light emitted from the plurality of blue LEDs 128 is light guide plate (FIG. In the process of being incident into the light guide plate (123 of FIG. 1) through the light incident surface of FIG. Make it incident inside.

Therefore, light leakage is prevented from occurring at the light incidence portion of the light guide plate (123 of FIG. 1), and the light efficiency incident to the light guide plate (123 of FIG. 1) is increased, thereby improving light efficiency.

In particular, by forming the ink layer blue, it is possible to prevent the yellow color defect from occurring in the light incidence portion of the light guide plate (123 in FIG. 1).

In more detail, when the ink layer is formed of the most widely used white light to reflect light in the B region of the PCB 200, the white ink layer has a low wavelength band (400 to 480 nm) including the blue wavelength band. There is a problem that does not reflect light efficiently.

Accordingly, even when the blue light emitted from the blue LED 128 passes through the bar-shaped quantum dot plate (127 of FIG. 1), the white light is a PCB having a white ink layer. When the light is reflected by the region B of the light source 200 and entered into the light guide plate 123 of FIG. 1, only light in the wavelength band except for the wavelength band corresponding to blue light is reflected to enter the light guide plate 123 of FIG. 1.

That is, only the light of the red and green wavelength bands is reflected by the white ink layer formed in the region B of the PCB 200 to be incident into the light guide plate 123 of FIG. 1.

Accordingly, since the light incident portion corresponding to the B region of the PCB 200 has a yellow color mixed with red and green, the yellow color defect of the light incident portion of the light guide plate (123 of FIG. 1) may occur as shown in FIG. 4. Will be.

However, by forming the blue ink layer 210 in the region B of the PCB 200 of the present invention, the light reflected by the region B of the PCB 200 among the white light and incident into the light guide plate 123 of FIG. 1 is blue. White light including light in the wavelength band may be reflected.

In addition, even though only light except for the blue wavelength band of the white light is reflected, the light guide plate (123 in FIG. 1) becomes yellow, but the yellow color of the light guide plate (123 in FIG. 1) and the PCB ( The blue of the blue ink layer 210 formed in the region B of 200 may be mixed so that white light may be felt.

FIG. 5 is a schematic cross-sectional view of some cross-section of FIG. 1 modularized.

As shown, the LED assembly 129 and the light guide plate 123 formed of a reflector plate 125, a light guide plate 123, and a PCB 200 on which the blue LED 128 and the blue LED 128 are mounted. The sheets 121 are stacked to form a backlight unit (120 of FIG. 1).

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 edges by the support main 130, and the cover bottom 150 is coupled to the rear surface thereof, and the upper edge and side surfaces of the liquid crystal panel 110 are separated. Wrapping top cover 140 is coupled to the support main 130 and cover bottom 150.

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 128 faces the light incident surface of the light guide plate 123. For this purpose, the support main 130 is disposed on 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, blue light emitted from the plurality of blue LEDs 128 is parallel to the PCB 200, and the light incident surfaces of the PCB 200 and the light guide plate 123 are positioned perpendicular to each other.

Here, although only one blue LED 128 of the LED assembly 129 is shown in the drawing, a plurality of blue LEDs 128 are mounted on the PCB 200 spaced apart from each other at a predetermined interval and receive driving power from the outside. do.

In this case, the PCB 200 is formed to cover a part of the light guide plate 123, and the blue ink layer 210 is formed on one surface of the light guide plate 123 of the PCB 200 covering the light guide plate 123. have.

In the backlight unit (120 of FIG. 1) of the present invention, a bar-shaped quantum dot plate 127 is interposed between the blue LED 128 and the light guide plate 123, and thus emitted from the blue LED 128. The blue light is realized as white light having excellent optical characteristics in the process of passing through the bar-shaped quantum dot plate 127, and the white light having excellent optical characteristics passes into the light guide plate 123 through the light incident surface of the light guide plate 123. Incident.

The white light incident into the light guide plate 123 is uniformly spread to a wide area of the light guide plate 123 by a plurality of total reflections in the light guide plate 123, and is emitted toward the liquid crystal panel 110, and passes through the optical sheet 121. The surface light source is processed to have a higher luminance surface light source, thereby providing the liquid crystal panel 110 with white light of the surface light source having excellent optical characteristics.

In addition, the white light implemented in the process of passing through the bar-shaped quantum dot plate 127 through the blue ink layer 210 formed on the PCB 200 passes through the light guide plate 123 through the light incident surface of the light guide plate 123. In the process of being incident therein, the light emitted toward the upper direction of the blue LED 128, that is, the PCB 200 is reflected to be incident to the light guide plate 123.

Therefore, light leakage is prevented from occurring at the light incidence part of the light guide plate 123 and the light efficiency of the light guide plate 123 is increased, thereby improving light efficiency.

In particular, by forming the ink layer in blue, it is possible to prevent the yellow color defect from occurring in the light incident portion of the light guide plate 123.

As described above, in the backlight unit of the present invention, a bar-shaped quantum dot plate 127 is formed by mixing red light emitting nanoparticles and green light emitting nanoparticles in front of the blue LED 128 emitting blue light. In this case, the blue light emitted from the blue LED 128 may implement white light having excellent optical characteristics in the course of passing through the bar-shaped quantum dot plate 127 in which the red light emitting nanoparticles and the green light emitting nanoparticles are mixed. do.

Therefore, the backlight unit (120 of FIG. 1) of the present invention uses a blue LED 128 having a low color reproducibility as a light source of the backlight unit (120 of FIG. 1). As the white light implemented by the quantum dot plate 127 penetrates the color filter layers (not shown) of red, green, and blue (B) colors of the liquid crystal panel 110, the color reproduction rate is improved. do. This satisfies the color coordinates of BT.709, which is a color coordinate system representing color gamut of HDTV (High Definition Television).

In addition, a plurality of blue LEDs 128 are mounted, and by forming the blue ink layer 210 on one surface of the PCB 200 covering the light guide plate 123, the yellow color defect of the light guide plate 123 is generated. Can be prevented.

Meanwhile, in the above-described structure, the light source LED 129a is a blue LED emitting blue light. At this time, the bar-shaped quantum dot plate 127 is formed by mixing red light emitting nanoparticles and green light emitting nanoparticles. Although the structure has been described, the bar-shaped quantum dot plate 127 may be formed of yellow light emitting nanoparticles having a quantum confinement effect.

In addition, the backlight unit (120 of FIG. 1) having the above-described structure is generally called a side light method, and according to the purpose, a plurality of LEDs 128 may be arranged on the PCB 200 in multiple layers. .

In addition, it is also possible to include a plurality of sets of each of the LED assembly 129 and to interpose corresponding to each other along the side edge portions of the cover bottom 150 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 polarizers
121: optical sheet, 123: light guide plate, 125: reflector plate
127: bar-shaped quantum dot plate
129: LED assembly (129: blue LED, 200: PCB)
130: support main (131: protruding jaw)
140: top cover, 150: cover bottom
210: blue ink layer

Claims (7)

A reflector;
A light guide plate mounted on an upper portion of the reflective plate;
LEDs including a plurality of blue LEDs arranged along a light incidence surface of the light guide plate and outputting light toward the light incidence surface, and a plurality of blue LEDs are mounted and a blue ink layer is formed on one surface of the light guide plate. An assembly;
A quantum dot plate having a bar shape interposed between the plurality of blue LEDs and a light incident surface of the light guide plate;
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 bar shaped quantum dot plate to excite the light emitted from the plurality of blue LEDs to implement white light.
The method of claim 1,
The PCB has a bar shape, and on one edge side of the PCB, the plurality of blue LEDs are arranged at regular intervals so as to emit light toward the other edge of the PCB along the longitudinal direction, and the blue ink layer is Liquid crystal display device formed on the other edge side of the PCB.
The method of claim 1,
And the PCB is positioned perpendicular to the light incident surface of the light guide plate, and the other edge side of the PCB on which the blue ink layer is formed covers a part of the light incident part of the light guide plate.
The method of claim 1,
The bar-shaped quantum dot plate is a liquid crystal display device that is cured by mixing the red light emitting nano particles and green light emitting nano particles having a quantum confinement effect.
The method of claim 1,
The bar-shaped quantum dot plate is a liquid crystal display in which yellow light emitting nanoparticles having a quantum confinement effect is cured.
The method according to any one of claims 4 and 5,
The light emitting nanoparticles are selected from one of CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, InP, GaP, GaInP2, PbS, ZnO, TiO2, AgI, AgBr, Hg12, PbSe, In2S3, In2Se3, Cd3P2, Cd3As2 or GaAs LCD display device.
The method according to any one of claims 4 and 5,
The light emitting nanoparticles are composed of a core including any material selected from the group consisting of CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe and HgS, and CdSe, CdTe, CdS, ZnSe, ZnTe, ZnS, HgTe and HgS. Liquid crystal display device having a core-shell structure (core-shell) consisting of a shell of any material selected from the group.

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