KR20120066325A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: A liquid crystal display device is provided to prevent degradation problem of display quality due to brightness un-uniform. CONSTITUTION: An LED(Light Emitting Diode) assembly(129) includes a plurality of LEDs(128) and a PCB(Printed Circuit Board)(200). A modulating film is formed on the PCB. A plurality of optical sheets is installed on the light guide sheet. The liquid crystal panel is installed on a plurality of optical sheets. A support main covers edge of the liquid crystal panel. A cover bottom is composed 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 a liquid crystal display device that can prevent a hot spot and an LED mura phenomenon 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, in the case of the LED used as the light source of the backlight unit of the liquid crystal display device, a hot spot, which is one of the problems of the appearance of the backlight unit, occurs.

That is, the LED is incident on the liquid crystal panel 10 after the light emitted from the adjacent two to three LEDs overlap and mixed with each other to provide a surface light source, in this case, the light in the area between the neighboring LEDs As the overlaps with each other, the area between the LEDs appears brighter than the areas corresponding to the LEDs, and the position between the LEDs (dark part) and the dark part (dark part) adjacent to the LED 22 are contrasted so that the position of the LED is recognized. Phenomenon occurs.

This is called a hot spot failure.

As a result, an LED mura phenomenon occurs, and furthermore, a problem of deterioration of display quality of the liquid crystal display device due to luminance unevenness is caused.

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 prevent problems such as LED mura, and to prevent a problem of deterioration of display quality due to uneven brightness of a liquid crystal display device. It is a second object to do.

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; PCBs arranged along the light incidence surface of the light guide plate, the plurality of LEDs emitting light toward the light incidence surface, and the plurality of LEDs mounted thereon, and having a brightness control film absorbing some light or reducing light reflection. An LED assembly comprising; 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 consisting of a bottom surface and a side surface thereof in close contact with the support main back surface, and the brightness control film providing a liquid crystal display device corresponding to an area where light emitted from the plurality of LEDs overlaps and is mixed with each other. do.

In this case, the PCB is a bar (bar) shape, one edge side of the PCB is arranged at a predetermined interval spaced apart so that the plurality of LEDs to emit light toward the other edge of the PCB along the longitudinal direction, the brightness control film is It is formed on the other edge side of the PCB corresponding to the area between the neighboring LED, the PCB is sequentially made of a PCB base, an insulating layer, a power wiring layer and a reflective layer, the brightness control film on the top of the reflective layer Located.

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 brightness control film is formed covers a part of the light incident part of the light guide plate, and the brightness control film is black or gray.

As described above, the present invention by forming a brightness control film on the PCB corresponding to the area where the light emitted from the neighboring LEDs overlap and mix with each other, thereby preventing the hot spot phenomenon occurs There is.

As a result, the LED mura phenomenon can be prevented from occurring, and further, the display quality of the liquid crystal display due to the luminance unevenness can be prevented from occurring.

1 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.
Figure 2a is a perspective view schematically showing an LED assembly according to an embodiment of the present invention.
2B is a plan view of FIG. 2A.
3a to 3b are photographs for comparing a hot spot phenomenon between a general liquid crystal display and a liquid crystal display according to an exemplary embodiment of the present invention.
4 is a schematic cross-sectional view of a partial cross section of FIG. 1 modularized.

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 direction of the liquid crystal molecules is changed by the electric field between the pixel electrode and the common electrode, thereby indicating the transmittance difference.

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 positioned at one side of the light guide plate 123 so as 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 spaced apart from each other by a predetermined interval. It includes a PCB 200 to be mounted.

Although not shown in the drawings, the liquid crystal display of the present invention is equipped with an LED driving circuit (not shown) for controlling the on / off of the LED assembly 129, these are usually the cover bottom 150 back Close contact to minimize the overall size.

Thus, a plurality of LEDs 128 are electrically connected to the LED driving circuit (not shown), one side on the PCB 200 is provided with a flexible cable (Flexible cable: 220, see FIG. 2A), such as FPC, By using the bending characteristics of the flexible cable 220 (refer to FIG. 2A), the flexible cable 220 is connected to the LED driving circuit (not shown) on the rear surface of the cover bottom 150.

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, on the PCB 200 on which the LED 128 is mounted, a brightness control film 210 (see FIG. 2A) for adjusting the brightness of light emitted from the LED 128 is formed.

That is, the brightness control film 210 (refer to FIG. 2A) is located in a region where light emitted from neighboring LEDs 128 overlaps among lights emitted from the plurality of LEDs 128, and reflects light in the region. To reduce brightness.

Through this, it is possible to prevent the occurrence of a hot spot failure, it is possible to prevent the occurrence of LED mura phenomenon. We will discuss this in more detail later.

The light guide plate 123 into which the light emitted from the plurality of LEDs 128 is incident is spread evenly to a large area of the light guide plate 123 while the light incident from the LED 128 propagates through the light guide plate 123 by several total reflections. The surface light source is provided 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.

As described above, the LED assembly 129 of the present invention is adjacent to each other by forming a brightness control film 210 (see Fig. 2a) to adjust the brightness of the light emitted from the LED 128 on the PCB (200) As the light in the area between the LEDs 128 overlaps each other, hot spots in which the areas between the LEDs 128 appear brighter than the areas corresponding to the LEDs 128 may be prevented from occurring.

As a result, the LED mura phenomenon can be prevented from occurring, and the display quality of the liquid crystal display due to the luminance unevenness can be prevented from occurring.

FIG. 2A is a perspective view schematically illustrating an LED assembly according to an embodiment of the present invention, and FIG. 2B is a plan view of FIG. 2A.

In this case, in FIG. 2B, the emission light for each of the LEDs 128 is displayed together for convenience of description.

As shown, the LED assembly 129 includes a plurality of LEDs 128 and a PCB 200 in which the plurality of LEDs 128 are mounted by surface mount technology (SMT) at regular intervals. do.

The plurality of LEDs 128 emits light having the colors of red (R), green (G), and blue (B), respectively, and may also realize white light by color mixing by lighting the plurality of RGB LEDs 128 at once. Each LED 128 emits white light toward the light guide plate 123 of FIG. 1, including an LED chip (not shown) that emits all the colors of RGB or emits white light.

The LED 128 that implements white light may be composed of a blue LED chip (not shown) and a yellow phosphor, and the yellow phosphor is yttrium (Y) aluminum (Al) doped with cerium (Ce) having a wavelength of 530 to 570 nm. It is preferable to use YAG: Ce (T3Al5O12: Ce) series phosphor which is garnet.

In addition, an LED chip (not shown) may be used as a UVLED chip. When using the UV LED chip, the phosphor (not shown) is composed of three colors of phosphors of red (R), green (G), and blue (B). Emission color can be selected by adjusting the compounding ratio of phosphor (R), green (G), and blue (B).

In this case, the red phosphor is a YOX (Y 2 O 3: EU) -based phosphor made of yttrium oxide (Y 2 O 3) and europium (EU) compound having a 611 nm wavelength, and the green (G) phosphor is a 544 nm wavelength. Is a LAP (LaPo4: Ce, Tb) -based phosphor which is a compound of phosphoric acid (Po4), lanthanum (La), and terbium (Tb), and the blue (B) phosphor has a barium wavelength of 450 nm. It is preferable to use BAM blue (BaMgAl 10 O 17: EU) -based phosphor, which is a compound of Ba), magnesium (Mg), aluminum oxide-based material, and europium (EU).

Here, the dominant wavelength is referred to as the wavelength of the phosphor that generates the highest luminance in each of red (R), green (G), and blue (B).

Here, the PCB 200 includes a power wiring layer 205, an insulating layer 203, a PCB base 201, and a reflective layer 207 on the power wiring layer 205, on which metal wiring (not shown) is formed. The base 201 supports the reflective layer 207, the power wiring layer 205, the insulating layer 203, and other components by mounting them on top, and dissipates heat generated from the plurality of LEDs 128 to the bottom side. Do it.

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 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 addition, the reflective layer 207 is formed on the power supply wiring layer 205. The reflective layer 207 is a white material capable of reflecting light, and includes a reflection function as well as an insulation function.

That is, the reflective layer 207 serves to protect the metal wiring (not shown) of the power wiring layer 205.

At this time, a part of the metal wiring (not shown) connected to the LED 128 is partially exposed.

In addition, the reflective layer 207 uses a white material having a high light reflectivity, so that light emitted from the LED 128 is incident on the light guide plate 123 of FIG. 1. The light emitted toward 200 is reflected to be incident into the light guide plate 123 of FIG. 1.

Accordingly, light leakage is prevented from occurring in the region between the LED 128 and 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. .

The reflective layer 207 is formed through a photo solder resist (PSR) process.

At this time, the brightness control film 210 is formed on the PCB 200 of the present invention, corresponding to the area D between the front LEDs 128 emitted from the LEDs 128.

That is, the PCB 200 is divided into a region where the LED 128 is mounted (hereinafter referred to as “A region”) and a region that guides light emitted from the LED 128 (hereinafter referred to as “B region”). The LEDs 128 are mounted adjacent to one edge side of the PCB 200, that is, spaced apart from the A region by a predetermined distance, wherein the plurality of LEDs 128 are opposite to one edge of the PCB 200. It is mounted on the PCB 200 to emit light toward the edge, that is, the B region.

The light emitted from the plurality of LEDs 128 has a certain directivity angle, and the light emitted from the LEDs 128 adjacent to each other in order to uniform the light intensity of the light incident portion of the light guide plate 123 of FIG. After overlapping and mixing, the light guide plate 123 of FIG. 1 is allowed to enter the light guide plate.

Therefore, the light emitted from the plurality of LEDs 128 mounted in the area A of the PCB 200 is overlapped and mixed with each other corresponding to the area B of the PCB 200 to be incident into the light guide plate 123 of FIG. 1.

At this time, the LED assembly 129 of the present invention is characterized in that to form a brightness control film 210 in the B region of the PCB 200 corresponding to the region in which the light emitted from the plurality of LEDs 128 overlap and mix with each other It is done.

Here, the brightness control film 210 is made of black or gray as a whole for efficient light shielding.

That is, the brightness control film 210 is formed in the area B of the PCB 200 corresponding to the area D of the plurality of LEDs 128, the brightness control film 210 is adjacent to each other LED 128 In the process of overlapping and mixing light emitted from each other, to reduce the amount of light reflected by the reflective layer 207 on the PCB 200 or to absorb a portion of the light.

Therefore, as the light in the area D between neighboring LEDs 128 overlaps and is mixed with each other, the area D between the LEDs 128 becomes brighter than the area C corresponding to the LEDs 128. It is possible to prevent the occurrence of visible hot spots.

As a result, the LED mura phenomenon can be prevented from occurring, and the display quality of the liquid crystal display due to the luminance unevenness can be prevented from occurring.

In more detail, the light emitted from the LED 128 is compared between the LEDs 128 where the light emitted from the neighboring LEDs 128 overlaps and is mixed with each other, compared to the region C corresponding to the LEDs 128. The area D becomes brighter.

Therefore, a phenomenon in which the position of the LED 128 is recognized by contrasting the light (bright part) of the area D between the LED 128 and the dark part (dark part) which is the area C corresponding to the LED 128 is compared. Hot spots will occur.

As a result, an LED mura phenomenon occurs, and furthermore, a problem of deterioration of display quality of the liquid crystal display device due to luminance unevenness is caused.

At this time, the light emitted from the LED 128 is further improved by the reflective layer 207 formed on the PCB 200, at this time, to absorb the light corresponding to the inter-region D of the LED 128 or By forming the brightness control film 210 that can reduce the reflection, the light emitted from the neighboring LED 128 to each other absorbs a part of the light in the area (D) between the LED 128 overlapping and mixing with each other, The amount of light reflected by the reflective layer 207 on the PCB 200 is reduced.

Therefore, the phenomenon in which the inter-region D of the LED 128 appears brighter than the region C corresponding to the LED 128 can be prevented.

 3A and 3B are photographs for comparing a hot spot phenomenon between a general liquid crystal display and a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 3A illustrates a general liquid crystal display device, in which a portion corresponding to an interregion (D of FIG. 2B) of an LED (128 of FIG. 2B) in which light emitted from neighboring LEDs (128 of FIG. 2B) overlaps and is mixed with each other. It can be seen that the hot spot phenomenon that appears relatively bright compared to the region (C of FIG. 2B) corresponding to the LED (128 of FIG. 2B) can be seen.

In contrast, FIG. 3B is a liquid crystal display according to an exemplary embodiment of the present invention, and the brightness control film 210 of FIG. 2B corresponds to a region where light emitted from neighboring LEDs (128 in FIG. 2B) overlaps and is mixed with each other. ), A portion corresponding to the interregion (D in FIG. 2B) of the LED (128 in FIG. 2B) in which the light emitted from the neighboring LEDs (128 in FIG. 2B) overlaps and mixes with each other is It can be seen that the hot spot phenomenon, which is relatively bright compared to the region (C of FIG. 2B) corresponding to 128, does not occur.

That is, among the lights emitted from a plurality of LEDs (128 in FIG. 2B), an area between the LEDs (128 in FIG. 2B), which is a region where light emitted from neighboring LEDs (128 in FIG. 2B) overlaps and is mixed, In FIG. 2B, a hot spot phenomenon occurs, which is relatively bright compared to a region (C of FIG. 2B) corresponding to the LED (128 of FIG. 2B). The liquid crystal display according to the embodiment of the present invention is a PCB ( In FIG. 2B, light emitted from neighboring LEDs (128 in FIG. 2B) overlaps and mixes with each other (D in FIG. 2B). By forming a brightness control film (210 of FIG. 2B) that can reduce absorption and reflection, between LEDs (128 of FIG. 2B), which are areas where light emitted from neighboring LEDs (128 of FIG. 2B) overlaps and is mixed. The area (D in FIG. 2B) is hotter than the area (C in FIG. 2B) corresponding to the LEDs (210 in FIG. 2B). Would be prevented by the pot it occurs.

Therefore, the LED mura phenomenon can be prevented from occurring, and further, the display quality of the liquid crystal display due to the luminance unevenness can be prevented from occurring.

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

As illustrated, the LED assembly 129 including the reflector plate 125, the light guide plate 123, and the PCB 200 on which the LED 128 and the LED 128 are mounted is mounted on the light guide plate 123. 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 by a method such as adhesive, so that one surface of the LED 128, from which light is emitted, faces the light guide plate 123, the light incident surface, for this purpose, the support main 130 is in 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 light emitted from the plurality of 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.

The light emitted from the LED 128 is incident into the light guide plate 123, and the light incident into the light guide plate 123 is uniformly spread to a large area of the light guide plate 123 by a plurality of total reflections in the light guide plate 123. It is emitted toward the panel 110, and processed into a higher luminance surface light source in the course of passing through the optical sheet 121, thereby providing the liquid crystal panel 110 with white light of the surface light source having excellent optical characteristics.

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

At this time, the PCB 200 is formed to cover a part of the light guide plate 123, and thus, in the process of the light emitted from the LED 128 is incident into the light guide plate 123, that is, the upper part of the LED 128. The light emitted toward the PCB 200 is reflected to be incident to the light guide plate 123.

Therefore, light leakage is prevented from occurring in the region between the LED 128 and the light guide plate 123, and the light efficiency is increased by increasing the amount of light incident into the light guide plate 123.

In addition, the brightness control film 210 is formed on one surface of the PCB 200 that covers the light guide plate 123 and toward the light guide plate 123.

Brightness control film 210 is formed corresponding to the area (D in Fig. 2b) of the LED 128 is mounted in a plurality spaced apart a predetermined interval along the longitudinal direction of the PCB 200, LED 128 neighboring each other The light emitted from absorbs some of the light in the region where it overlaps and blends with each other, or reduces the amount of light reflected by the reflective layer (207 in FIG. 2B) on the PCB 200.

Through this, it is possible to prevent a phenomenon in which the region (D of FIG. 2B) between the LEDs 128 appears brighter than the region (C of FIG. 2B) corresponding to the LED 128.

As described above, the backlight unit (120 of FIG. 1) of the present invention is located on the PCB 200 corresponding to the region (D in FIG. 2B) where light emitted from neighboring LEDs 128 overlap and mix with each other. By forming the brightness control film 210, it is possible to prevent the phenomenon that the area thereof looks brighter than the area (C of FIG. 2B) corresponding to the LED (128).

Therefore, it is possible to prevent the occurrence of hot spots, thereby preventing the occurrence of the LED mura phenomenon, and to prevent the display quality of the liquid crystal display device from deteriorating due to the luminance unevenness.

Meanwhile, 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.

129: LED Assembly
128: LED, 200: PCB
210: brightness control film, 207: reflective layer, 220: flexible cable

Claims (5)

A reflector;
A light guide plate mounted on an upper portion of the reflective plate;
PCBs arranged along the light incidence surface of the light guide plate, the plurality of LEDs emitting light toward the light incidence surface, and the plurality of LEDs mounted thereon, and having a brightness control film absorbing some light or reducing light reflection. An LED assembly comprising;
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
The brightness control film includes a liquid crystal display device which is positioned corresponding to the area where the light emitted from the plurality of LEDs overlap and mix with each other.
The method of claim 1,
The PCB has a bar shape, the plurality of LEDs are arranged at regular intervals on one edge side of the PCB so that the plurality of LEDs emit light toward the other edge of the PCB, and the brightness control film is separated from each other. A liquid crystal display device formed on the other edge side of the PCB corresponding to the area between the neighboring LED.
The method of claim 1,
The PCB comprises a PCB base, an insulating layer, a power wiring layer and a reflective layer in sequence, wherein the brightness control film is located on the reflective layer.
The method of claim 1,
Wherein 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 brightness control film is formed covers a part of the light incident part of the light guide plate.
The method of claim 1,
The brightness control film is a liquid crystal display device made of black or gray.

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