KR20120042174A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: A liquid crystal display device is provided to maximize light incident efficiency by optimizing a structure of an LED housing. CONSTITUTION: A light guide plate(142) is located on a rear side of a liquid crystal display panel. An LED array(145) is located on a side of the light guide plate. An LED housing surrounds the LED array. A reflecting plate(143) is arranged on a rear side of the light guide plate. The thickness of the light guide plate is the same as or thinner than the thickness of the LED array.

Description

[0001] LIQUID CRYSTAL DISPLAY DEVICE [0002]

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device for supplying light to a liquid crystal display panel using a plurality of light emitting diodes (LEDs).

BACKGROUND ART In general, a liquid crystal display device is a display device in which data signals according to image information are individually supplied to pixels arranged in a matrix, and a desired image is displayed by adjusting light transmittance of the pixels.

Accordingly, the liquid crystal display includes a liquid crystal display panel in which pixels are arranged in a matrix and a driving unit for driving the pixels.

The liquid crystal display panel is composed of a color filter substrate and an array substrate bonded together to maintain a uniform cell gap facing each other, and a liquid crystal layer formed in a cell gap between the color filter substrate and the array substrate.

In this case, a common electrode and a pixel electrode are formed on the liquid crystal display panel where the color filter substrate and the array substrate are bonded to apply an electric field to the liquid crystal layer.

Therefore, when the voltage of the data signal applied to the pixel electrode is controlled while the voltage is applied to the common electrode, the liquid crystal of the liquid crystal layer rotates by dielectric anisotropy according to the electric field between the common electrode and the pixel electrode. Characters or images are displayed by transmitting or blocking light for each pixel.

In this case, the liquid crystal display is a light-receiving element that does not emit light by itself and displays an image by controlling the transmittance of light from the outside, so that a separate device for irradiating light to the liquid crystal display panel, that is, a backlight unit Is required.

The backlight unit has a lamp disposed on one side or both sides of the liquid crystal display panel so that light is reflected, diffused and collected through the light guide plate, the reflecting plate, and the optical sheets to transmit the light to the front surface of the liquid crystal display panel. An edge type and a lamp are disposed on a rear surface of the liquid crystal display panel so that light is directly transmitted to the front surface of the liquid crystal display panel.

1 is a cross-sectional view schematically illustrating a structure of a general liquid crystal display device, and schematically illustrates a part of a side surface of a liquid crystal display device having an edge type backlight unit.

As shown in the drawing, a general liquid crystal display device is a liquid crystal display panel that is largely injected between the color filter substrate 5 and the array substrate 10 to output an image, the liquid crystal display is installed on the rear of the liquid crystal display panel The backlight unit 40, which emits light over the entire surface of the panel, and the guide panel 24, the upper case 21, the lower cover 22, and the like, which fix and couple the liquid crystal display panel and the backlight unit 40 to each other. Consists of case parts.

In this case, the backlight unit 40 will be described in detail. An LED array 45 for generating light on the lower cover 22 and an LED printed circuit board (PCB) for driving the LEDs 44 ) And a reflecting plate 43, and the light guide plate 42 is installed in the light exit direction of the LED array 45.

In addition, a lamp housing 23 secures the LED array 45 and the LED printed circuit board 44, wherein the lamp housing 23 prevents the reflective plate 43 from sagging down. And a reflector support 23a.

Light generated by the LED array 45 is incident on the side of the light guide plate 42 of a transparent material, and the reflecting plate 43 disposed on the rear surface of the light guide plate 42 is transmitted to the rear surface of the light guide plate 42. The light is reflected toward the optical sheets 41 on the upper surface of the light guide plate 42 to reduce light loss and improve uniformity.

A liquid crystal display panel including the color filter substrate 5 and the array substrate 10 is seated on the upper portion of the backlight unit 40 configured as described above, and is coupled to each other through adhesive tapes 15a and 15b and the upper case 21. The liquid crystal display device is constructed.

In this case, upper and lower polarizers 1 and 11 are attached to outer surfaces of the color filter substrate 5 and the array substrate 10, respectively, and the upper polarizer 1 polarizes light passing through the liquid crystal display panel. The lower polarizer 11 polarizes light via the optical sheets 41.

Meanwhile, as the display industry develops, demands for slimming displays and reducing production costs are increasing.

At this time, in order to slim the existing backlight unit, the thickness of each major component should be minimized. However, the minimization of thickness, performance of optical efficiency, instrument reliability, and the like have a limitation in minimizing thickness because a trade off relationship is established.

In particular, when the thickness of the light guide plate is reduced in order to slim down the backlight unit, since the thickness of the light guide plate is smaller than the thickness of the LED array, the amount of light that is not incident to the light guide plate is lost.

2A and 2B are cross-sectional views illustrating light loss due to slimming of the light guide plate.

As shown in FIG. 2A, the edge type LED backlight unit used in the related art usually has a light emitting surface of the LED array 45 having a size smaller than the thickness d of the light guide plate 42 so as to direct the angle of the LED array 45. The incidence efficiency of the light emitted with H is high.

Accordingly, only a central portion of the LED array 45 and the light guide plate 42 is designed and manufactured without requiring a special light incident structure.

However, as shown in FIG. 2B in order to slim down the backlight unit, when the thickness d 'of the light guide plate 42' is reduced, the thickness d 'of the light guide plate 42' is the thickness of the LED array 45. Since it is smaller, the amount of light lost without being incident to the light guide plate 42 'is increased. That is, since a large portion of the light emitted from the LED array 45 does not directly enter the light guide plate 42 ', it is lost by first entering another apparatus or is partially reflected and re-entered the light guide plate 42', so that the light loss increases rapidly. .

As a result, even if a slim liquid crystal display device cannot be developed or manufactured, problems such as excessive power consumption or cost increase are caused.

In addition, in the conventional light receiving structure in which the LED array and the light guide plate are in a straight line, the LED printed circuit board cannot be bent and thus it is impossible to apply to a flexible display that is expected to be spotlighted in the future.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a liquid crystal display device that realizes slimming of an edge type LED backlight unit.

Another object of the present invention is to provide a liquid crystal display device in which the structure of the LED housing is optimized in response to the slimming of the backlight unit.

Further objects and features of the present invention will be described in the configuration and claims of the invention which will be described later.

In order to achieve the above object, the liquid crystal display device of the present invention comprises a liquid crystal display panel for outputting an image; A light guide plate on a rear surface of the liquid crystal display panel; An LED array positioned on a side of the light guide plate and configured to generate a plurality of light emitting diodes (LEDs); An LED housing surrounding the LED array between the light guide plate in the LED array and reflecting light toward the light guide plate; And a reflector disposed on a rear surface of the light guide plate, wherein the thickness of the light guide plate is equal to or smaller than the thickness of the LED array.

At this time, the LED housing is characterized in that the surface is attached to a reflector or a silver reflective coating.

The LED housing may be made of a metal material such as aluminum or a polymer material such as PC (polycarbonate) or ABS (Acrylonitrile Butadiene Styrene).

The lower LED housing is connected to or integrally formed with the reflecting plate below the light guide plate.

The length of the reflecting portion of the LED housing is characterized in that the distance from the end of the light guide plate to the light emitting surface of the LED array or located longer behind the light emitting surface of the LED array.

The LED housing is characterized in that the inclined to surround the LED array between the light guide plate in the LED array.

At this time, the angle of the inclined surface of the LED housing is characterized in that about 0 ° ~ 45 ° depending on the difference between the thickness of the LED array and the light guide plate.

The LED housing may be divided into two parts, an upper part and a lower part, and extend toward the light guide plate to overlap the light guide plate.

The light guide plate may be disposed by retreating a predetermined distance from the LED array in consideration of expansion by heat during driving, and the inclined surface of the LED housing may start at the end of the light guide plate or start forward from the end of the light guide plate toward the LED array. It features.

On the other hand, the LED housing is characterized in that consisting of a rectangle surrounding the LED array between the light guide plate in the LED array.

In this case, the LED housing may be separated into two parts, the upper and lower, characterized in that it extends toward the light guide plate and overlaps the light guide plate.

The light guide plate is disposed by retreating a predetermined distance from the LED array in consideration of expansion by heat during driving, and the rectangular structure of the LED housing starts at the end of the light guide plate or starts forward from the end of the light guide plate toward the LED array. It is characterized by.

The light guide plate is characterized in that it is disposed about 0 ~ 3.0mm away from the rectangular structure of the LED housing.

On the other hand, the LED housing is characterized in that it employs a top view (top view) arranged vertically with respect to the light guide plate.

At this time, it is characterized in that it further comprises an optical lens disposed between the LED array and the light guide plate to change the direction of the light.

The LED housing is characterized by consisting of a linear LED housing and an inclined LED housing to surround the LED array and the optical lens, respectively, between the LED array and the optical lens in the light guide plate.

The optical lens is disposed in the light exit direction of the LED array, and the light guide plate is installed in the light exit direction of the optical lens.

The optical lens has a surface in direct contact with the LED array and the light guide plate, and the other surface is formed of a straight line (cross-section triangle), an oblique line (cross-section trapezoid), a circle, an ellipse (face arc), and the like.

The material of the optical lens is characterized in that it comprises a polymer such as PC (polycarbonate), polymethyl methacrylate (PMMA), polystyrene (PS), MS or glass or silicon compounds.

The optical lens is attached to the LED array and the light guide plate through the optical adhesive or fixed by a fixture.

The linear LED housing may be divided into two parts, left and right, while the inclined LED housing extends toward the light guide plate and overlaps the light guide plate.

As described above, the liquid crystal display according to the present invention realizes slimming of the edge type LED backlight unit, and maximizes the light receiving efficiency by optimizing the structure of the LED housing in response to the slimming of the backlight unit. As a result, it is possible to reduce power consumption, improve heat dissipation characteristics, reduce the use of optical sheets, and reduce manufacturing costs.

In addition, the top view LED array, which has a higher luminous flux and longer lifetime than the side view LED array, can be disposed perpendicularly to the light guide plate, which is advantageous for securing the light quantity and implements a flexible liquid crystal display device. There is an advantage to that.

1 is a cross-sectional view schematically showing a structure of a general liquid crystal display device.
2A and 2B are cross-sectional views illustrating light loss due to slimming of the light guide plate.
3 is a cross-sectional view schematically showing the structure of the LED package according to the first embodiment of the present invention.
4 is a cross-sectional view schematically showing another structure of the LED package according to the first embodiment of the present invention.
FIG. 5 is a cross-sectional view schematically illustrating a structure of a liquid crystal display device according to a first embodiment of the present invention to which the LED package shown in FIG. 4 is applied. FIG.
FIG. 6 is a simulation result comparing and comparing light incidence efficiency with and without the LED housing according to the first embodiment of the present invention. FIG.
7 is a cross-sectional view schematically showing the structure of an LED package according to a second embodiment of the present invention.
8 is a cross-sectional view schematically showing another structure of the LED package according to the second embodiment of the present invention.
9 is a schematic cross-sectional view of a structure of a liquid crystal display according to a second exemplary embodiment of the present invention to which the LED package shown in FIG. 8 is applied.
10 is a simulation result comparing and comparing the light receiving efficiency with or without the LED housing according to the second embodiment of the present invention.
11 is a cross-sectional view schematically showing the structure of an LED package according to a third embodiment of the present invention.
12 is a sectional view schematically showing another structure of the LED package according to the third embodiment of the present invention.
13 is a simulation result showing the light incidence efficiency when the LED housing according to the third embodiment of the present invention is applied.

Hereinafter, exemplary embodiments of a liquid crystal display according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view schematically showing the structure of the LED package according to the first embodiment of the present invention, Figure 4 is a cross-sectional view schematically showing another structure of the LED package according to the first embodiment of the present invention.

3 and 4 are formed of substantially the same components except for whether the LED housing according to the first embodiment of the present invention extends toward the light guide plate and overlaps the light guide plate, for convenience of description. Like elements are designated by like reference numerals.

3 and 4, the LED package according to the first embodiment of the present invention is a LED array 145 consisting of a plurality of LEDs for generating light and LED printing for driving the LED array 145 LED housings 150 and 155 surround the circuit board 144 and the LED array 145 to reflect light toward the light guide plate 142.

The light guide plate 142 is provided in the light exit direction of the LED array 145, and a plurality of LEDs constituting the LED array 145 are positioned at predetermined intervals between the LEDs for overall brightness uniformity. Done.

The LED printed circuit board 144 may be formed of a metal core printed circuit board (MPCB) in which an aluminum layer is stacked on a lower surface of the LED printed circuit board to radiate heat generated from the plurality of LEDs, which are light sources, to the outside. .

In this case, in the LED package according to the first embodiment of the present invention, the thickness of the light guide plate 142 is at least equal to the thickness of the LED array 145 or smaller than the thickness of the LED array 145 for the slimming of the backlight unit. It is characterized by the design.

As described above, the slimming of the edge type LED backlight unit is progressing, but the manufacture of the thin LED array is delayed, so that the thickness of the light guide plate 142 is smaller than that of the light emitting surface of the LED array 145. In this case, in order to minimize the light that is not incident to the light guide plate 142, it is necessary to introduce a new light incident structure, the LED package according to the first embodiment of the present invention is a light guide plate (LED) in the LED array 145 A mechanical structure having an inclination surrounding the LED array 145, ie, the LED housings 150 and 155, is introduced between the 142 and the LED array 145.

In this case, as the light having a directing angle is reflected by the LED housings 150 and 155 and is incident toward the light guide plate 142, light that has been lost in the absence of the existing LED housing structure can be minimized. As a result, power consumption, heat dissipation characteristics, optical sheet use, and manufacturing cost can be obtained.

In this case, the LED housings 150 and 155 may improve light receiving efficiency by attaching a reflector to a surface thereof or increasing a reflectance through a process such as a silver reflecting coating. In addition, the length of the portion reflected from the inclined surfaces of the LED housings 150 and 155 is equal to the distance from the end of the light guide plate 142 to the light emitting surface of the LED array 145 or behind the light emitting surface of the LED array 142. It can be located longer.

The LED housings 150 and 155 may be formed of a metal material such as aluminum (Al) or a polymer material such as PC (polycarbonate) or ABS (Acrylonitrile Butadiene Styrene), and the like. The angle of the inclined surface may be about 0 ° to 45 ° according to the difference between the thicknesses of the LED array 145 and the light guide plate 142.

Meanwhile, the LED housings 150 and 155 may be divided into two parts, an upper part and a lower part. As shown in FIG. 4, the LED housing 155 extends toward the light guide plate 142 and the light guide plate 142. Can overlap.

In this case, the lower LED housing 155 may be connected to or integrally formed with a reflector (not shown) under the light guide plate.

In addition, the light guide plate 142 may be disposed by retreating from the LED array 142 by a predetermined distance in consideration of expansion by heat during driving. In this case, the inclined surfaces of the LED housings 150 and 155 may start at the end of the light guide plate 142 or at the front of the LED array 142 at the end of the light guide plate 142.

Hereinafter, a liquid crystal display device having an LED package according to the first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 5 is a cross-sectional view schematically illustrating a structure of a liquid crystal display according to a first embodiment of the present invention to which the LED package shown in FIG. 4 is applied.

As shown in the figure, the liquid crystal display device according to the first embodiment of the present invention is a liquid crystal display panel in which a liquid crystal is injected between the color filter substrate 105 and the array substrate 110 to output an image, the liquid crystal display A backlight unit 140 installed at the rear of the panel to emit light over the entire surface of the liquid crystal display panel, and a guide panel 124 and an upper case 121 for fixing and coupling the liquid crystal display panel and the backlight unit 140 to each other. And a case part such as a lower cover 122.

In this case, the backlight unit 140 has an edge type in which an LED package is disposed on at least one side of the liquid crystal display panel, and the LED package includes an LED array 145 for generating light and an LED printed circuit for driving the LED. The LED housing 155 surrounds the substrate 144 and the LED array 145 to reflect light toward the light guide plate 142.

The light guide plate 142 is provided in the light exit direction of the LED array 145, wherein the liquid crystal display according to the first embodiment of the present invention measures at least the thickness of the light guide plate 142 in order to reduce the size of the backlight unit. The thickness of the LED array 145 is equal to or smaller than the thickness of the LED array 145 is designed.

In addition, as described above, the LED housing having an inclination surrounding the LED array 145 between the LED array 145 and the light guide plate 142 in order to minimize the light that does not enter the light guide plate 142 and is lost ( 155) is introduced.

In this case, the LED housing 155 may improve the light receiving efficiency by attaching a reflector to the surface or increasing the reflectance through a process such as a silver reflecting coating. In addition, the length of the portion reflected from the inclined surface of the LED housing 155 is equal to the distance from the end of the light guide plate 142 to the light emitting surface of the LED array 145 or longer behind the light emitting surface of the LED array 142. Can be located.

The LED housing 155 may be made of a metal material such as aluminum or a polymer material such as PC or ABS, and the angle of the inclined surface of the LED housing 155 may be the thickness of the LED array 145 and the light guide plate 142. Depending on the difference, it can be set between 0 ° and 45 °.

In addition, the LED housing 155 may be divided into two parts of the upper and lower parts, and the upper and lower ends may extend toward the light guide plate 142 to overlap the light guide plate 142. In this case, the lower LED housing 155 may be connected to or integrally formed with the reflective plate 143 below the light guide plate.

In addition, the light guide plate 142 may be disposed by retreating from the LED array 142 by a predetermined distance in consideration of expansion by heat during driving. In this case, the inclined surface of the LED housing 155 may start at the end of the light guide plate 142 or at the front of the LED array 142 at the end of the light guide plate 142.

The lamp housing 123 fixes the LED array 145 and the LED printed circuit board 144. In this case, the lamp housing 123 has a reflector support to prevent the reflector 143 from sagging down. 123a.

The light generated by the LED array 145 is incident to the side of the light guide plate 142 of a transparent material, and the reflecting plate 143 disposed on the rear surface of the light guide plate 142 is transmitted to the rear surface of the light guide plate 142. The light is reflected toward the optical sheets 141 on the upper surface of the light guide plate 142 to reduce light loss and improve uniformity. In particular, the liquid crystal display according to the first exemplary embodiment of the present invention includes an LED housing 155 that surrounds the LED array 145 and reflects light toward the light guide plate 142 so that the loss of light can be minimized. do.

A liquid crystal display panel including the color filter substrate 105 and the array substrate 110 is seated on the upper portion of the backlight unit 140 configured as described above, and is coupled to each other through adhesive tapes 115a and 115b and the upper case 121. The liquid crystal display device is constructed.

In this case, upper and lower polarizers 101 and 111 are attached to the outer surfaces of the color filter substrate 105 and the array substrate 110, respectively, and the upper polarizer 101 polarizes light passing through the liquid crystal display panel. The lower polarizer 111 polarizes light via the optical sheets 141.

Although not shown in detail in the drawing, the color filter substrate 105 is a color filter composed of a plurality of sub-color filters for implementing colors of red (R), green (G), and blue (B). And a black matrix separating the sub-color filter and blocking light passing through the liquid crystal layer, and a transparent common electrode applying a voltage to the liquid crystal layer.

In addition, the array substrate 110 is formed on the pixel region and the thin film transistor, which is a switching element formed in a cross-section of the gate line and the data line, the plurality of gate lines and data lines that are arranged vertically and horizontally. It consists of a pixel electrode. In this case, the gate line and the data line are electrically connected to a gate printed circuit board (PCB) and a data printed circuit board through a tape tape carrier package (TCP) and a data tape carrier package, respectively. .

The liquid crystal display according to the first exemplary embodiment of the present invention configured as described above may derive an optimal light incident structure through the optical simulation, even though the thickness of the light guide plate is smaller than the light emitting surface of the LED array. .

6 is a simulation result comparing and comparing the light receiving efficiency with or without the LED housing according to the first embodiment of the present invention, wherein the height of the light emitting surface of the LED array is an example of 1.5T.

As shown in the figure, when the thickness of the light guide plate is thicker than the height of the light emitting surface of the LED array, it shows a relatively high light receiving efficiency regardless of the presence or absence of the LED housing according to the first embodiment of the present invention, In the case of decreasing below 2.0T, it can be seen that there is a large difference in light receiving efficiency depending on the presence or absence of the LED housing according to the first embodiment of the present invention.

By introducing the LED housing structure according to the first embodiment of the present invention, for example, when the thickness of the light guide plate is 0.8T, it can be seen that the light receiving efficiency is improved to utilize about 94% of the light emitted from the LED array. have.

On the other hand, it can be seen that the light incident efficiency in the absence of the LED housing structure as described above is significantly reduced to about 53% of the light emitted from the LED array.

7 is a cross-sectional view schematically showing the structure of the LED package according to a second embodiment of the present invention, Figure 8 is a cross-sectional view schematically showing another structure of the LED package according to a second embodiment of the present invention.

7 and 8 are substantially the same components except for whether the light guide plate according to the second embodiment of the present invention retreats from the LED array by a predetermined distance, and the same components are provided for convenience of description. Are denoted by the same reference numerals.

As shown in FIG. 7 and FIG. 8, the LED package according to the second embodiment of the present invention is a LED array 245 consisting of a plurality of LEDs for generating light and LED printing for driving the LED array 245 The LED substrate 250 surrounds the circuit board 244 and the LED array 245 to reflect light toward the light guide plate 242.

The light guide plate 242 is installed in the light exit direction of the LED array 245, and a plurality of LEDs constituting the LED array 245 are positioned at predetermined intervals between the LEDs for overall luminance uniformity. Done.

The LED printed circuit board 244 may be formed of a metal PCB in which an aluminum layer is stacked on a lower surface thereof to radiate heat generated from the plurality of LEDs as light sources to the outside.

In this case, in the LED package according to the second embodiment of the present invention, the thickness of the light guide plate 242 is equal to at least the thickness of the LED array 245 for the slimming of the backlight unit as in the first embodiment of the present invention. Or it is designed to be smaller than the thickness of the LED array 245.

The LED package according to the second embodiment of the present invention introduces a rectangular LED housing 250 surrounding the LED array 245 between the light guide plate 242 in the LED array 245. It is done.

In this case, as the light having a directivity angle is reflected by the LED housing 250 and is incident toward the light guide plate 242, it is possible to minimize the light lost when there is no existing LED housing structure. As a result, power consumption, heat dissipation characteristics, optical sheet use, and manufacturing cost can be obtained.

 The LED housing 250 may improve light receiving efficiency by attaching a reflector to a surface thereof or increasing a reflectance through a process such as a silver reflecting coating. In addition, the length of the portion reflected from the LED housing 250 is equal to the distance from the end of the light guide plate 242 to the light emitting surface of the LED array 245 or longer than the light emitting surface of the LED array 242. Can be.

The LED housing 250 may be made of a metal material such as aluminum or a polymer material such as PC or ABS.

In addition, the LED housing 250 may be divided into two parts, an upper part and a lower part, and the LED housing 250 may extend toward the light guide plate 242 to overlap the light guide plate 242.

In this case, the lower LED housing 250 may be connected to or integrally formed with a reflector (not shown) under the light guide plate.

In addition, the light guide plate 242 may be disposed by retreating a predetermined distance from the LED array 242 in consideration of being expanded by heat during driving. In this case, the rectangular structure of the LED housing 250 may start at the end of the light guide plate 242 or may start from the front in the direction of the LED array 242 at the end of the light guide plate 242. In addition, the light guide plate 242 may be disposed about 0 to 3.0mm away from the rectangular structure of the LED housing 250, and shows a high light receiving efficiency in the case of 0 to 1.5mm.

Hereinafter, a liquid crystal display device having an LED package according to the second embodiment of the present invention will be described in detail with reference to the accompanying drawings.

9 is a cross-sectional view schematically illustrating a structure of a liquid crystal display according to a second exemplary embodiment of the present invention to which the LED package illustrated in FIG. 8 is applied.

As shown in the figure, the liquid crystal display device according to the second embodiment of the present invention is a liquid crystal display panel in which a liquid crystal is injected between the color filter substrate 205 and the array substrate 210 to output an image, the liquid crystal display A backlight unit 240 installed at a rear side of the panel to emit light over the entire surface of the liquid crystal display panel, and a guide panel 224 and an upper case 221 for fixing and coupling the liquid crystal display panel and the backlight unit 240 to each other. And a case part such as a lower cover 222.

In this case, the backlight unit 240 is configured of an edge type in which the LED package is disposed on at least one side of the liquid crystal display panel, the LED package is an LED array 245 for generating light and an LED printed circuit for driving the LED The LED housing 250 surrounds the substrate 244 and the LED array 245 and reflects light toward the light guide plate 242.

The light guide plate 242 is provided in the light exit direction of the LED array 245, wherein the liquid crystal display according to the second embodiment of the present invention has a thickness of at least the thickness of the light guide plate 242 in order to make the backlight unit slim. The thickness of the LED array 245 may be equal to or smaller than the thickness of the LED array 245.

In addition, as described above, the rectangular LED housing 250 surrounding the LED array 245 between the LED array 245 and the light guide plate 242 in order to minimize light that is not incident to the light guide plate 242 and is lost. ) Is introduced.

In this case, the LED housing 250 may improve the light receiving efficiency by attaching a reflecting plate to the surface or increasing the reflectance through a process such as a silver reflecting coating. In addition, the length of the portion reflected from the LED housing 250 is equal to the distance from the end of the light guide plate 242 to the light emitting surface of the LED array 245 or longer than the light emitting surface of the LED array 242. Can be.

The LED housing 250 may be made of a metal material such as aluminum or a polymer material such as PC or ABS.

In addition, the LED housing 250 may be separated into two parts of the upper and lower parts, and the upper and lower ends may extend toward the light guide plate 242 to overlap the light guide plate 242. In this case, the lower LED housing 250 may be connected to or integrally formed with the reflective plate 243 below the light guide plate.

In addition, the light guide plate 242 may be disposed by retreating a predetermined distance from the LED array 242 in consideration of being expanded by heat during driving. In this case, the rectangular structure of the LED housing 250 may start at the end of the light guide plate 242 or may start from the front in the direction of the LED array 242 at the end of the light guide plate 242. In addition, the light guide plate 242 may be disposed about 0 to 3.0mm away from the rectangular structure of the LED housing 250, and shows a high light receiving efficiency in the case of 0 to 1.5mm.

The lamp housing 223 fixes the LED array 245 and the LED printed circuit board 244, and the lamp housing 223 has a reflector support to prevent the reflector 243 from sagging downward. 223a.

The light generated by the LED array 245 is incident on the side of the light guide plate 242 of a transparent material, and the reflective plate 243 disposed on the rear surface of the light guide plate 242 is transmitted to the rear surface of the light guide plate 242. The light is reflected toward the optical sheets 241 on the upper surface of the light guide plate 242 to reduce light loss and improve uniformity. In particular, the liquid crystal display according to the second exemplary embodiment of the present invention includes an LED housing 255 that surrounds the LED array 245 and reflects the light toward the light guide plate 242, thereby minimizing the loss of light. do.

A liquid crystal display panel including the color filter substrate 205 and the array substrate 210 is seated on the upper portion of the backlight unit 240 configured as described above, and is coupled to each other through adhesive tapes 215a and 215b and the upper case 221. The liquid crystal display device is constructed.

In this case, upper and lower polarizers 201 and 211 are attached to outer surfaces of the color filter substrate 205 and the array substrate 210, respectively, and the upper polarizer 201 polarizes light passing through the liquid crystal display panel. The lower polarizer 211 polarizes light via the optical sheets 241.

The liquid crystal display according to the second exemplary embodiment of the present invention configured as described above is the same as the first exemplary embodiment of the present invention, even if the thickness of the light guide plate is smaller than that of the light emitting surface of the LED array. It is possible to derive the light receiving structure of.

FIG. 10 is a simulation result comparing and comparing light incidence efficiency with and without the LED housing according to the second embodiment of the present invention. In this case, the height of the light emitting surface of the LED array is 1.5T.

As shown in the figure, when the thickness of the light guide plate is thicker than the height of the light emitting surface of the LED array, it shows a relatively high light receiving efficiency regardless of the presence or absence of the LED housing according to the second embodiment of the present invention, In the case of decreasing below 2.0T, it can be seen that there is a large difference in light receiving efficiency depending on the presence or absence of the LED housing according to the second embodiment of the present invention.

By introducing the LED housing structure according to the second embodiment of the present invention, for example, when the thickness of the light guide plate is 0.8T, it can be seen that the light receiving efficiency is improved to utilize about 85% of the light emitted from the LED array. have.

On the other hand, it can be seen that the light incident efficiency in the absence of the LED housing structure as described above is significantly reduced to about 53% of the light emitted from the LED array.

11 is a cross-sectional view schematically showing a structure of an LED package according to a third embodiment of the present invention, Figure 12 is a cross-sectional view schematically showing another structure of the LED package according to a third embodiment of the present invention.

11 and 12 are substantially the same components except for the lens shape according to the third embodiment of the present invention, and the same components are denoted by the same reference numerals for convenience of description.

As shown in FIGS. 11 and 12, the LED package according to the third embodiment of the present invention includes an LED array 345 including a plurality of LEDs for generating light and an LED printing for driving the LED array 345. Optical lenses 360 and 365 which are disposed between the circuit board 344 and the LED array 345 and the light guide plate 342 to change the direction of light, and the optical lenses 360 and 365 and the LED array 345 are provided. It is composed of LED housings 350 and 355 that surround and reflect light toward the light guide plate 342.

At this time, the LED array 345 according to the third embodiment of the present invention is a top view having a higher luminous flux and lifespan as compared to the side view method as in the first and second embodiments of the present invention described above. Top view) is employed, and in this case, the light guide plate 342 may be disposed perpendicularly to the light guide plate 342, which is advantageous to secure the amount of light and has the advantage of implementing a flexible liquid crystal display.

The optical lenses 360 and 365 are disposed in the outgoing direction of the LED array 345, and the light guide plate 342 is provided in the outgoing directions of the optical lenses 360 and 365.

The optical lenses 360 and 365 are in contact with the LED array 345 and the light guide plate 342 in a straight line, and the remaining surfaces are straight lines (cross-section triangles), curved lines (cross-section trapezoids), circles, and ellipses (face-side arcs). It can be manufactured in various shapes, and exhibits higher light efficiency characteristics when the cross section is triangular. For reference, FIG. 11 illustrates an LED package according to a third embodiment of the present invention in a case where a surface which is not in contact with the LED array 345 and the light guide plate 342 is a straight line. The LED package according to the third embodiment of the present invention is shown by way of example when the surfaces not in contact with the LED array 345 and the light guide plate 342 are curved lines.

The material of the optical lenses 360 and 365 may include a polymer such as PC, polymethyl methacrylate (PMMA), polystyrene (PS), MS, or a glass or silicon compound.

The optical lenses 360 and 365 may be attached to the LED array 345 and the light guide plate 342 through an optical adhesive or fixed by an instrument.

The LED printed circuit board 344 may be composed of a metal PCB (MPCB) in which an aluminum layer is stacked on a lower surface thereof to radiate heat generated from the plurality of LEDs as light sources to the outside. In addition, the LED printed circuit board 344 may be made of FR4 or FPCB (Flexible PCB) in addition to the MPCB. In particular, when the PCB is FR4 and FPCB, the flexible liquid crystal display may be manufactured through the structure. It is possible.

At this time, the LED package according to the third embodiment of the present invention is the same as the first and second embodiments of the present invention to reduce the thickness of the light guide plate 342 to at least the thickness of the LED array (345) The thickness is equal to or smaller than the thickness of the LED array 345 is characterized in that the design.

The LED package according to the third exemplary embodiment of the present invention may include the LED array 345 and the optical lens 360 between the LED array 345 and the light guide plate 342 in the optical lenses 360 and 365. It is characterized by introducing a linear LED housing 350 and the inclined LED housing 355 respectively surrounding 365.

In this case, as the light having a directivity angle passes through the optical lenses 360 and 365 and then enters the light guide plate 342 without loss, the light that is lost may be minimized, and the optical lens 360 in the light guide plate 342 may be minimized. 365) and the LED housings 350 and 355 surrounding the LED array 345 may be added to obtain higher light efficiency.

In particular, an inner portion of the LED housings 350 and 355 in contact with the LED array 345, the light guide plate 342, and the optical lenses 360 and 365 may have a reflector attached thereto, or may increase reflectance through a process such as a silver reflective coating. As a result, the light receiving efficiency can be improved.

The LED housings 350 and 355 may be made of a metal material such as aluminum or a polymer material such as PC or ABS.

In addition, the linear LED housing 350 may be separated into two parts on the left and right sides, while the inclined LED housing 353 may extend toward the light guide plate 342 to overlap the light guide plate 342. .

In this case, although not shown in the drawing, the LED housing 350 on the right side may be connected to or integrally formed with a reflector (not shown) under the light guide plate.

In the liquid crystal display according to the third embodiment of the present invention configured as described above, the light efficiency of the light guide plate is smaller than the light emitting surface of the LED array in the same manner as the first and second embodiments of the present invention. It is possible to derive an optimal light incident structure that can be maximized.

13 is a simulation result showing light incidence efficiency when the LED housing according to the third embodiment of the present invention is applied.

As shown in the figure, by introducing the LED housing structure according to the third embodiment of the present invention, for example, when the thickness of the light guide plate is 0.8T, in the case of the LED housing 1 shown in FIG. It can be seen that the light receiving efficiency is improved to utilize about 88.3% of the light. In addition, it can be seen that the LED housing 2 shown in FIG. 12 can utilize about 61.2% of the light emitted from the LED array.

In this case, the light incidence efficiency is lowered than in the case of the first embodiment of the present invention. However, the LED package may be substantially larger than the case of the first embodiment of the present invention. It is possible to secure a light beam easier than ever.

Many details are set forth in the foregoing description but should be construed as illustrative of preferred embodiments rather than to limit the scope of the invention. Therefore, the invention should not be defined by the described embodiments, but should be defined by the claims and their equivalents.

105,205: color filter substrate 110,210: array substrate
140,240: backlight unit 142,242,342: light guide plate
143,243: Reflector 144,244,344: LED printed circuit board
145,245,345: LED Array 150,155,250,350,355: LED Housing
360,365: Optical Lens

Claims (21)

A liquid crystal display panel which outputs an image;
A light guide plate on a rear surface of the liquid crystal display panel;
An LED array positioned on a side of the light guide plate and configured to generate a plurality of light emitting diodes (LEDs);
An LED housing surrounding the LED array between the light guide plate in the LED array and reflecting light toward the light guide plate; And
And a reflector disposed on a rear surface of the light guide plate, wherein the thickness of the light guide plate is equal to or smaller than the thickness of the LED array. The liquid crystal display device according to claim 1, wherein the LED housing has a reflective plate or a silver reflective coating on the surface thereof. The liquid crystal display of claim 1, wherein the LED housing is made of a metal material such as aluminum or a polymer material such as PC (polycarbonate), ABS (Acrylonitrile Butadiene Styrene), or the like. The liquid crystal display of claim 1, wherein the lower LED housing is connected to or integrally formed with a reflecting plate below the light guide plate. The liquid crystal display of claim 1, wherein a length of a portion reflected from the LED housing is equal to a distance from an end of the light guide plate to a light emitting surface of the LED array or longer behind the light emitting surface of the LED array. . The liquid crystal display device according to claim 1, wherein the LED housing has an inclination to surround the LED array between the LED array and the light guide plate. 7. The liquid crystal display device according to claim 6, wherein the angle of the inclined surface of the LED housing is about 0 ° to 45 ° according to the difference between the thickness of the LED array and the light guide plate. The liquid crystal display of claim 6, wherein the LED housing may be divided into two parts, an upper part and a lower part, and extended toward the light guide plate to overlap the light guide plate. The light guide plate of claim 6, wherein the light guide plate is disposed to be retracted from the LED array by a predetermined distance in consideration of expansion by heat during driving, and an inclined surface of the LED housing starts at the end of the light guide plate or is directed toward the LED array at the end of the light guide plate. LCD, characterized in that starting from the front. The liquid crystal display device of claim 1, wherein the LED housing comprises a quadrangle surrounding the LED array between the LED array and the light guide plate. The liquid crystal display of claim 10, wherein the LED housing may be divided into two parts, an upper part and a lower part, and extended toward the light guide plate to overlap the light guide plate. The light guide plate of claim 10, wherein the light guide plate is disposed with a predetermined distance from the LED array in consideration of expansion by heat during driving, and the rectangular structure of the LED housing starts at the end of the light guide plate or at the end of the light guide plate. And a liquid crystal display device starting from the front in the direction. The liquid crystal display of claim 12, wherein the light guide plate is disposed about 0 to 3.0 mm away from the rectangular structure of the LED housing. The liquid crystal display device according to claim 1, wherein the LED housing adopts a top view method disposed vertically with respect to the light guide plate. 15. The liquid crystal display of claim 14, further comprising an optical lens disposed between the LED array and the light guide plate to change the direction of light. The liquid crystal display device according to claim 15, wherein the LED housing comprises a linear LED housing and an inclined LED housing which respectively enclose the LED array and the optical lens between the LED array and the optical lens and the light guide plate. . 16. The liquid crystal display device according to claim 15, wherein the optical lens is disposed in the outgoing direction of the LED array, and the light guide plate is provided in the outgoing direction of the optical lens. 16. The optical lens of claim 15, wherein a surface of the optical lens contacting the LED array and the light guide plate is a straight line, and the other surface is formed of a straight line (cross section triangle), an angled line (cross section trapezoid), a circle and an ellipse (face arc). A liquid crystal display device. The method of claim 15, wherein the optical lens material comprises a polymer such as polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), MS, or a glass or silicon compound A liquid crystal display device. The liquid crystal display device according to claim 15, wherein the optical lens is attached to the LED array and the light guide plate through an optical adhesive or fixed by an instrument. The liquid crystal display of claim 16, wherein the linear LED housing may be divided into two parts, left and right, while the inclined LED housing extends toward the light guide plate and overlaps the light guide plate.

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