KR100761055B1 - Direct type LED backlight unit - Google Patents

Abstract

 The present invention provides an LED chip for generating light; A plurality of red (R), green (G) and blue (B) light emitting LED package including a LED lens means positioned on the path of light generated by the LED chip to guide the light path of the substrate chassis A backlight unit provided on an upper side, comprising: a chassis having a heat dissipation coating layer, an LED package having a reflective coating layer, an LED edge reflecting cover disposed at an edge of the LED package, and the LED package having a diamond on a substrate Characterized in that arranged.

Description

Direct type LED backlight unit {Direct type LED backlight unit}

1 is a schematic front view of a backlight unit having a conventional LED package.

FIG. 2 is a vertical cross-sectional view illustrating a state in which a unit LED package constituting the backlight unit of FIG. 1 is installed.

3 is a graph showing a change in temperature with time at each measurement point of the conventional backlight unit according to FIG. 1.

4 is a front view schematically showing an arrangement state of the LED package of the backlight unit having the LED package according to the present invention.

FIG. 5 is a vertical cross-sectional view illustrating an installed state of a unit LED package of a backlight unit having a heat dissipation structure without a fan among one embodiment of the backlight unit of FIG. 4.

6A and 6B are vertical cross-sectional views illustrating an installed state of a unit LED package of a backlight unit having a heat dissipation structure in which a fan is installed as another embodiment of the backlight unit of FIG. 4.

7 is a cross-sectional view showing an embodiment of the coupling relationship between the LED package and the LED corner reflecting cover according to the present invention.

8 is a partial exploded cross-sectional view of FIG. 7.

FIG. 9 is a front view schematically illustrating a zone where a temperature is measured in order to measure a temperature distribution for each section of the backlight unit of the present invention.

FIG. 10 is a graph illustrating a change in temperature over time of a section of the backlight unit of FIG. 9.

<Description of the symbols for the main parts of the drawings>

100: backlight unit 112: horizontal frame

114: vertical frame 116: LED package

118: LED package group 120: board chassis

122: metal PCB 126: reflective plate

132: heat conductive sheet 136: diffusion plate

138: diffusion sheet 140: BEF sheet

142: DBEF-D sheet 146: pan support

148: heat dissipation fan 160: LED corner reflection cover

162: heat dissipation coating layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct type back light unit using an LED light source, and more particularly, a direct light using an LED light source such that light generated from a red-green-blue (RGB) LED package is mixed to form white light. Type backlight unit.

In general, a flat panel display is classified into a light emitting type and a light receiving type, and the light emitting type includes a cathode ray tube (CRT), an electroluminescent (EL) element, and a plasma display panel (PDP). And the light-receiving type include Liquid Crystal Display (LCD).

 Since the LCD itself is a light-receiving element that emits light and does not form an image, but receives light from the outside to form an image, a separate light source, for example, a so-called backlight is installed to allow an image to be observed in a dark place. .

The LCD backlight is classified into a direct type and an edge type according to the installation position of the light source. In the method of generating white light using the LED as a light source, white light is mixed by optically mixing red and green (RGB) LEDs. There is an RGB LED method for generating a light emitting diode, a method for mixing an ultraviolet LED and a red cyan phosphor, and a binary complimentary method for mixing a blue LED and a yellow phosphor. The LED light source has an advantage that it is not only fast response time compared to the CCFL used as a conventional light source, but also eco-friendly because it does not contain heavy metals such as mercury and is a solid solid element. In particular, the RGB LED system has excellent color expressing ability as compared to CCFL and other LED methods, which are conventionally used as a light source, and has been adopted for LED backlights for high-quality LCD TVs.

1 is a plan view illustrating an arrangement state of an LED package in a conventional backlight unit. When the plurality of LED packages 16 are arranged in a row to form the LED package group 18 on the substrate chassis 20 surrounded by the horizontal frame 12 and the vertical frame 14, the LED package groups 18 lined up. ) Again form multiple rows.

FIG. 2 is a cross-sectional view illustrating an installation of the unit LED package shown in FIG. 1. Referring to FIG. 2, a metal core printed circuit board (PCB) 34 is installed below the light emitting LED package 16, and the assembly of the LED package 16 and the metal core PBC 34 is installed. Is installed in the LED support frame 22.

Here, the thermal conductive sheet 32 is interposed between the metal core PCB 34 and the LED support frame 22 so that heat generated from the LED package 16 is transferred to the LED support frame 22. In addition, in order to spread the heat generated in the LED package 16 disposed on the LED support frame 22 in a wide section, a long heat conducting pipe 30 inside the LED support frame 22 is the LED support frame 22. It is installed through).

On the other hand, the peripheral portion surrounding the LED package 16 is provided with a reflecting plate 26 for reflecting the light generated from the LED package 16 to the exit surface, the space between the reflecting plate and the LED package 16 is a support plate Covered by (24).

Heat transmitted from the LED package 16 to the LED support frame 22 is radiated through the heat dissipation fins 44 formed on the rear surface of the substrate chassis 20 through the substrate chassis 20. In order to help the heat dissipation in this process, the heat dissipation fan 48 mounted on the fan support 46 is rotated so that the heat of the heat dissipation fin 44 is dissipated by the air generated thereby.

On the other hand, a diverter of the PMMA (polymethyl methacrylate) plate 28, on which an oval dot 50 is printed, is disposed above the LED package 16, and a diffusion plate 36 is disposed thereon. ), And an optical sheet, a diffusion sheet 38, a BEF sheet 40, and a DBED-D sheet 42, etc., are stacked thereon to correct luminance of light generated from the LED package.

The temperature change in each part of the backlight unit 10 in which the LED package 16 having the structure as shown in FIG. 2 is arranged as shown in FIG. 1 is shown in FIG. 3. Each point indicated in FIG. 3 indicates a point indicated by 1 to 6 in FIG. 1. Experimental conditions will be described later, and as can be seen from the graph of FIG. 3, the backlight unit maintains stable temperature characteristics during the operation time. However, the backlight unit having the structure as shown in FIG. 2 has a problem of having a complicated heat dissipation structure as shown in FIG. 2 unlike the direct type backlight structure of the conventional CCFL light source.

In addition, in the prior art, since the light generated from the LED package is reflected from the reflecting plate and proceeds to the exit surface, the amount of light falling to the area just below the LED package not covered by the reflecting plate is considerably low. In addition, a diverter of PMMA (polymethyl methacrylate) plate 28 on which an oval dot (50) is printed, which does not exist in a direct backlight structure by a conventional CCFL light source, is newly disposed. This also had a problem of low light efficiency.

In addition, in the prior art, since the LED packages are arranged in a line, there is a problem in that the degree of mixing R-G-B three colors is not constant.

In addition, the presence of a complex heat dissipation structure and diverter plate increases the weight of the backlight and has a problem of inferior merchandise.

The present invention is to solve the above problems, an object of the present invention is to minimize the amount of light loss in the backlight unit having an LED package, high light efficiency, excellent uniformity of RGB colors, and has a relatively simple structure It is possible to achieve a light weight, and at the same time to provide a backlight unit with excellent heat dissipation performance.

The backlight unit according to the present invention for achieving the above object,

LED chip to generate light; A plurality of red (R), green (G) and blue (B) light emitting LED package including a LED lens means positioned on the path of light generated by the LED chip to guide the light path of the substrate chassis As a backlight unit provided on the upper side,

And an LED edge reflecting cover disposed at an edge of the LED package.

Here, the LED edge reflection cover is provided with a coupling groove to be fastened to the LED package.

In addition, the LED edge reflecting cover is preferably extended in a skirt shape downward from the edge of the LED package.

The LED edge reflecting cover is preferably formed of a high reflectance material.

In particular, the LED edge reflection cover is preferably formed of polycarbonate (PC).

The LED package is provided with a reflective coating layer on a part of the LED lens means.

A metal PCB is interposed between the substrate chassis and the LED package so that the LED package is disposed on the surface of the metal PCB.

In addition, a thermal conductive sheet may be further interposed between the substrate chassis and the metal PCB.

Here, the substrate chassis may be a flat plate shape,

Optionally, the substrate chassis may be protruding in shape.

In addition, a heat dissipation coating layer is formed on at least one exposed portion of the metal PCB and the substrate chassis.

In addition, a heat spreader may be further interposed between the substrate chassis and the metal PCB.

On the other hand, the LED package is arranged in a rhombus to form an LED package group.

In addition, the LED package group includes a plurality of LED packages of one of red, green, and blue LED packages.

In particular, the LED package group preferably includes two green LED packages, one red LED package, and one blue LED package among the red, green, and blue LED packages.

Further, the green LED packages of the LED package group are arranged to face each other in a lozenge.

Furthermore, the LED package groups are arranged with certain rules.

In particular, the horizontal pitch between the plurality of LED package groups is preferably twice the interval of the horizontal diagonal of the LED package constituting the rhombic LED package group, and has a 180-degree rotational symmetry between the horizontally adjacent LED package groups. .

In addition, the vertical pitch between a plurality of the LED package group is the rhombus It is preferable that it is twice the interval of the vertical diagonal of the LED package constituting the LED package group.

Hereinafter, a direct backlight unit according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

4 is a front view illustrating a layout in which an LED package is disposed in an LED backlight unit according to a preferred embodiment of the present invention, and FIG. 5 is a temporary view showing a state in which the LED package shown in FIG. 4 is mounted and installed in the backlight unit. 6 is a vertical cross-sectional view of FIG.

Referring to FIG. 4, in the case of a backlight unit according to an exemplary embodiment of the present invention, the red (R), green (G), and blue (B) LED packages 116 may include a horizontal frame 112 and a vertical frame 114. The LED package group 118 is formed by grouping on the substrate chassis 120 enclosed by the substrate. At this time, the plurality of LED packages 116, in particular four LED packages are arranged in a rhombus to form the LED package group 118.

The lozenge requires four vertices, so four LED packages are also required. In this case, the LED package group 118 is a plurality of LED packages of one color of red, green and blue LED packages, in particular two. More preferably, among the four LED packages forming four vertices of a rhombus, two green LED packages, one red LED package, and one blue LED package are preferable.

In constructing the LED package group 118 with such an LED package 116, the green LED package is arranged to face each other at the vertex of the lozenge. Thus, as shown in the partial enlarged view of FIG. 4, any one LED package is arranged in the order of G-R-G-B when viewed in the clockwise direction.

In addition, as shown in FIG. 4, the LED package group 118 in which the LED packages 116 are gathered is disposed on the substrate chassis 120 in a matrix shape. That is, the LED package group 118 is continuously arranged in the horizontal direction and the vertical direction.

In the arrangement of the LED package group 118, the horizontal pitch between the plurality of LED package groups is preferably twice the interval of the horizontal diagonal of the pair of opposing LED packages constituting the LED package group, the horizontal direction This allows 180 degree rotational symmetry between adjacent LED package groups. Therefore, as described above, if the arrangement of the LED package of one LED package group was GRGB in the clockwise direction, the arrangement of the LED package of the other LED package group immediately next to such package would be GBRG in the clockwise direction and the LED package for R and B The position of is changed up and down. In addition, the vertical pitch between the plurality of LED package groups is preferably twice the vertical diagonal spacing of the pair of facing LED packages constituting the LED package group. On the other hand, the arrangement direction of the LED package of the LED package group continuously running in the vertical direction is the same as in the horizontal direction. That is, as shown in FIG. 4, when the LED package of any one LED package group is GRGB in the clockwise direction, the LED package of another LED package group located closest to the top and bottom also has the arrangement of GRGB in the clockwise direction. .

Referring to FIG. 5, which is a cross-sectional view of an embodiment in which the unit LED package 116 disposed in the above arrangement is installed in the backlight unit 100, the backlight unit may include an LED chip (not shown) that generates light and the LED. An LED package 116 is provided that includes LED lens means for guiding the path of light generated by the chip. In particular, the LED lens means is provided with a reflective coating layer. The LED package 116 is disposed above the substrate chassis 120, and a metal PCB 122 is interposed between the substrate chassis 120 and the LED package 116. Thus, the LED package 116 is installed on the upper surface of the metal PCB 122.

Meanwhile, the heat transfer sheet 132 is interposed between the substrate chassis 120 and the metal PCB 122 so that heat transferred from the LED package 116 to the metal PCB 122 is transferred through the heat conductive sheet 132. Conductive to the substrate chassis 120.

Although not shown in detail in the drawings, the metal PCB 122 in which the LED package is installed is a printed circuit board assembly in which an insulating layer is placed on an aluminum substrate and copper, which is a conductive wire metal, is disposed thereon.

A reflection plate 126 is disposed on the metal PCB 122 to reflect light generated from the LED package in the emission plane direction (upward direction in FIG. 5) in an area other than the location where the LED package 116 is disposed.

On the other hand, the peripheral edge of the LED package 116 is mounted with the LED corner reflective cover 160. The LED edge reflective cover 160 preferably extends in a skirt shape downward from the edge of the LED package 116. In addition, the LED edge reflecting cover 160 is preferably a material having a high reflectance, for example, it is preferably formed of a polycarbonate (PC) material.

The light generated from the LED package 116 is laterally refracted by the LED lens means, mixed with each other, and then travels toward the exit surface by the reflective plate 126 and the reflective cover 160.

Here, only the portion corresponding to the portion where each LED package 116 is located has a high luminance and the luminance of the portion where the LED package 116 is not disposed is low so that the luminance is not constant, LED package ( Above the 116 is an optical component that scatters light.

According to FIG. 5, the diffusion plate 136 is spaced apart from the upper side of the LED package 116, and the optical sheets 138, 140, and 142 are stacked and disposed above the diffusion plate 136.

Here, the optical sheet may be, for example, a diffusion sheet 138, a BEF sheet 140 (brightness enhancement film sheet), or a DBEF-D sheet 142 (dual brightness enhancement film sheet).

Meanwhile, a heat conductive sheet 132 is installed and disposed between the substrate chassis 120 and the metal PCB 122 to enhance the heat conduction effect. In addition, a heat spreader (Heat Spreader 180) or a heat pipe (Heat Pipe) with a high heat transfer speed is installed to increase the temperature uniformity of the substrate chassis 120 and the metal PCB 122. In the case of FIG. 5, the substrate chassis 120 is plate-shaped. Accordingly, a heat conductive sheet 132 and a heat spreader 180 are disposed above the substrate chassis 120, and a heat dissipation coating layer 162 is disposed on the lower surface thereof.

Accordingly, the heat generated in the LED package reaches the heat dissipation coating layer 162 via the metal PCB 122, the heat conduction sheet 132, and the substrate chassis 120, where the heat is dissipated to the atmosphere by air and dissipated. .

The heat generated from the LED package 116 is conducted not only downward but also laterally in the metal PCB 122 or the substrate chassis 120, and in particular, the lateral heat conduction is promoted by the heat spreader so that heat is transferred. It is evenly conducted and radiated to the whole of the backlight unit.

6A and 6B are vertical cross-sectional views illustrating a modification of FIG. 5. Referring to FIG. 6, the configuration of the substantial part is similar to that of FIG. 5. Therefore, the same components will be described with the same reference numerals.

Referring to FIG. 6A, the backlight unit includes an LED package 116 including an LED chip for generating light (not shown) and an LED lens unit for guiding a path of light generated by the LED chip. The LED package 116 is disposed on the upper side of the substrate chassis 120 'having a flat shape or a protruding shape to widen the heat dissipation area. A metal PCB 122 is disposed between the substrate chassis 120' and the LED package 116. ) Is intervened. Thus, the LED package 116 is installed on the upper surface of the metal PCB 122.

On the other hand, the heat transfer sheet 132 is interposed between the substrate chassis 120 'and the metal PCB 122, the heat transferred from the LED package 116 to the metal PCB 122, the heat conductive sheet 132 Conductive to the substrate chassis 120 through. In particular, the heat dissipation fan 148 is installed on the fan support 146 and disposed below the substrate chassis 120 'to enhance the heat dissipation effect.

A reflection plate 126 is disposed on the metal PCB 122 to reflect light generated from the LED package in the emission plane direction (upward direction in FIG. 6) in an area other than the location where the LED package 116 is disposed.

On the other hand, the peripheral edge of the LED package 116 is mounted with the LED corner reflective cover 160. The LED edge reflecting cover 160 preferably extends in a skirt shape downward from the edge of the LED package 116. In addition, the LED edge reflective cover 160 is preferably formed of a material having a high reflectance, for example, preferably formed of a polycarbonate (PC) material.

Then, the light generated from each of the red, green, and blue LED packages 116 is laterally refracted by the LED lens means and mixed with each other, and then proceeds toward the exit surface by the reflecting plate 126 and the reflecting cover 160. .

Here, only the portion corresponding to the portion where each LED package 116 is located has a high brightness, and the brightness of the portion where the LED package is not disposed is low, so that the brightness is not constant, the light on the upper side of the LED package An optical component is arranged that scatters light.

According to FIG. 6B, the diffusion plate 136 is disposed on the upper side of the LED package 116, and the optical sheets 138, 140, and 142 are stacked on the upper side of the diffusion plate 136.

On the other hand, the lower side of the substrate chassis 120, the heat dissipation fan 148 to enhance the heat dissipation effect is installed on the fan support 146 is disposed. In the case of FIG. 6, the substrate chassis 120 ′ is flat or has a protruding shape to extend the heat dissipation area, more specifically, a leg protruding shape. A thermally conductive sheet 132 is disposed above one side of the substrate chassis 120 ', and a heat dissipation coating layer 162' is disposed on at least one exposed portion of the metal PCB 122 and the substrate chassis 120 '. ) Is formed.

In other words, a heat dissipation coating layer 162 'is formed on the exposed portion of the lower surface of the metal PCB 122 that is not in contact with the substrate chassis 120' and the exposed portion of the substrate chassis.

Therefore, the heat generated from the LED package reaches the heat dissipation coating layer 162 'directly through the metal PCB 122, or radiates heat, or passes through the metal PCB 122, the thermal conductive sheet 132, and the substrate chassis 120'. To reach the heat dissipation coating layer 162 ', where the heat is dissipated to the atmosphere by the air blowing from the heat dissipation fan 148.

The general emissivity (ratio of radiant energy radiated from the surface of the actual material and radiant energy emitted from the black body) is in the range of 0.02 to 0.1, and the heat dissipation coating agent is preferably selected so that the emissivity of the heat dissipation coating layer is 0.9 to 0.95.

As in the case of FIG. 5, the heat generated in the LED package 116 is conducted not only downward in the metal PCB 122 or the substrate chassis 120 ′ but also laterally so that heat is transmitted to the entire backlight unit. It is evenly conducted and radiates heat.

7 and 8 are partial cross-sectional views of the LED package shown in FIGS. 5 and 6.

Referring to FIG. 7, an LED corner reflective cover 160 is disposed at an edge of the LED package 116. As shown in FIG. 8, the LED corner reflective cover 160 has a coupling groove 162 at the center thereof. With a structure, the LED lens 117 of the LED package is fitted into the coupling groove 162 is fastened. When the LED corner reflecting cover 160 is fastened to the LED package 116, the space between the reflecting plate 126 and the LED package 116 disposed under the periphery of the LED package 116 is completely covered by the LED corner reflecting cover ( 160).

The LED edge reflecting cover 160 has a skirt shape and extends obliquely downward from an edge of the LED package 116.

As such, when the LED edge reflecting cover 160 surrounds the periphery of the LED package 116, a portion generated by the LED 119 and refracted by the LED lens means 117 falls directly below the LED package 116. Since the light may also be reflected by the LED edge reflecting cover 160, the amount of light that proceeds to the exit surface is increased, the light efficiency is increased. To this end, the LED edge reflecting cover 160 is preferably formed of a material of high reflectivity.

Therefore, when assembling the backlight unit, the gap between the reflecting plate 126 and the LED package 116 should be minimized, and even if a gap occurs between the LED edge reflecting cover 160, the light loss is minimized. .

On the other hand, Figure 9 is a front view of the backlight unit schematically showing the point where the temperature was measured in the experiment for examining the heat radiation performance of the backlight unit of the present invention having the structure described above. 10 is a graph of temperature change with time at each point 1 to 3 of FIG. 9.

For reference, in order to explain in comparison with FIG. 3, which is a time versus temperature graph for the prior art, the experimental conditions for obtaining the graph of FIG. 3 will be described below.

The experiment in which the graph of FIG. 3 was obtained with respect to the conventional backlight unit was experimented with the back cover removed from the LCD TV employing the LED backlight unit, and the demo image was repeatedly displayed.

Specific experimental conditions of the backlight unit of the prior art are shown in Table 1 below.

Table 1

PWM driving condition Input power L (max), x, y, variable R G B Voltage 65.9 V 89.7 V 47.2 V 238W (max) 4014nit, x = 0.263 y = 0.214 (centered) Peak current 204mA / ch 492mA / ch 644 mA / ch Number of channels 5 channels 5 channels 5 channels Duty 54.2% 51.4% 57.7%

Referring to FIG. 3, which is a result of experiments performed under these conditions, the temperature change with time at each point in FIG. 1 is shown graphically. In Figure 1, points 1, 3, 4 and 5 are points on the metal core PCB and points 2 and 6 are points on the substrate chassis. In addition, Table 2 below shows the results obtained by arranging the optical and temperature characteristics of the backlight unit according to the experiments performed under the above conditions.

TABLE 2

Power Consumption Metric 9P minimum 9P maximum 9P average 9P uniformity 238 W Luminance [cd / m ² ] 3,392 4,014 3,663 84.5% Color coordinates [Wx] 0.2597 0.2650 0.263 98.0% Color Chart [Wy] 0.2098 0.2190 0.214 95.8%  Sheet Composition: Diffuser Plate / Diffuser Sheet / BEF / DBEF-D BLU Front Temperature: 32 ℃ Max. (RT24 ℃ Base) MPCB Temperature: 47 ℃ Max. (RT24 ℃ Base)

Referring to FIG. 3, in the conventional backlight unit, since the demo image is measured while repeatedly displaying the demo image, it can be seen that the variation of the temperature changes while vibrating. In addition, it can be seen that the heat pipe, the heat radiation fins, and the heat radiation fan are applied to maintain stable temperature characteristics of up to 47 ° C.

In contrast, the experimental results of the backlight unit according to the present invention will be described.

Experimental conditions for obtaining the graph shown in FIG. 10 are shown in Table 3 below.

TABLE 3

PWM condition Input power L, x, y variable R G B Voltage 72.0V 89.0V 81.0V 165 W 4024nit, x = 0.261 y = 0.211 (centered) Peak current 328mA / ch 334 mA / ch 340mA / ch Number of channels 3 channel 6 channels 3 channel Duty 48% 50% 51%

In addition, Table 4 below shows the results obtained by arranging the optical and temperature characteristics of the backlight unit according to the experiments performed under the above conditions.

Table 4

Power Consumption Metric 9P minimum 9P maximum 9P average 9P uniformity 165 W Brightness [cd / ㎡] 3,469 4,024 3,683 86.2% Color coordinates [Wx] 0.2574 0.2624 0.261 98.1% Color coordinates [Wy] 0.2068 0.2142 0.211 96.6%  Sheet Composition: Diffuser Plate / Diffuser Sheet / BEF / DBEF-D BLU Front Temperature: 30 ℃ Max. (RT25 ℃ Base) MPCB Temperature: 44 ℃ Max. (RT25 ℃ Base)

Referring to FIG. 10, which is a graph of temperature change with respect to time points 1 to 3 as shown in FIG. 9 under the above conditions, it can be seen that the variation in temperature is relatively large and shows stable change compared to FIG. 3. This simply shows that the heat generated in the LED package can be well dissipated in the structure of the backlight unit according to the invention. In addition, as can be seen in Table 4, when compared in the similar brightness and color coordinate conditions of Table 2, the power consumption of the backlight unit according to the present invention is low and the brightness and color coordinate uniformity show an improved result.

As described above, according to the direct type backlight unit of the structure according to the present invention, the following effects can be achieved.

First, the efficiency of light can be improved by reducing the amount of light emitted from the LED package. As a result, the power consumption of the backlight can be reduced.

Second, by providing an appropriate arrangement for mixing the light generated in each of the red, green, and blue LED package, it is possible to ensure the light of good purity and constant brightness, and improve the light uniformity throughout the backlight surface. .

Third, as a simple backlight structure, the heat generated from the LED package can be radiated to the outside to lower the operating temperature inside the backlight unit.

Fourth, since the diverter plate and the heat dissipation fin can be removed as a simple backlight structure, the backlight can be made thinner and lighter.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (20)

LED chip to generate light; A plurality of red (R), green (G) and blue (B) light emitting LED package including a LED lens means positioned on the path of light generated by the LED chip to guide the light path of the substrate chassis In the backlight unit provided on the upper side, And an LED edge reflecting cover disposed at an edge of the LED package, The LED package is spaced apart from each other arranged in a rhombus to form a group of LED packages, The LED package group is a direct type LED backlight unit comprising two green LED packages, one red LED package, and one blue LED package among red, green, and blue LED packages. The method of claim 1, The LED corner reflection cover is a direct type LED backlight unit, characterized in that it has a coupling groove to be fastened to the LED package. The method of claim 2, The LED corner reflective cover is a direct type LED backlight unit, characterized in that extending in the skirt shape downward from the edge of the LED package. The method of claim 3, wherein The LED corner reflective cover is a direct type LED backlight unit, characterized in that it comprises a polycarbonate (PC). delete The method of claim 1, Direct LED backlight unit, characterized in that the LED lens means is provided with a reflective coating layer. The method of claim 1, And a metal PCB is interposed between the substrate chassis and the LED package so that the LED package is disposed on a surface of the metal PCB. The method of claim 7, wherein The direct type LED backlight unit, characterized in that a thermal conductive sheet is further interposed between the substrate chassis and the metal PCB. The method of claim 8, And the substrate chassis has a flat plate shape. The method of claim 8, And the substrate chassis has a protruding shape. The method of claim 8, And a heat dissipation coating layer is formed on at least one exposed portion of the metal PCB and the substrate chassis. The method of claim 8, Direct LED backlight unit, characterized in that the heat spreader is further interposed between the substrate chassis and the metal PCB. delete delete delete The method of claim 1, And the green LED package of the LED package group is disposed to face each other in a rhombus. The method of claim 16, The LED package group is a direct type LED backlight unit, characterized in that arranged in a matrix shape. The method of claim 17, The horizontal pitch of the plurality of LED package group is a direct type LED backlight unit, characterized in that twice the interval of the horizontal diagonal of the LED package constituting the LED package group. The method of claim 17, The direct-type LED backlight unit, characterized in that the rotational symmetry between the nearest package group in a horizontal arrangement between a plurality of the LED package group. The method of claim 17, The vertical pitch of the plurality of the LED package group is a direct type LED backlight unit, characterized in that twice the interval of the vertical diagonal of the LED package constituting the LED package group.

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