KR101921166B1 - Liquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal display, and more particularly to a liquid crystal display including an edge type backlight unit.
According to an aspect of the present invention, since the LED assembly is positioned corresponding to each region of the light guide plate, the lightweight and thin edge type backlight unit can be used without increasing the cost and power consumption.
In addition, it is possible to implement a backlight division driving, thereby realizing a lively image. Further, brightness suitable for an image can be adjusted, and an image having a dark brightness has light of a dark brightness, Can be reduced.

Description

[0001] Liquid crystal display device [0002]

The present invention relates to a liquid crystal display, and more particularly to a liquid crystal display including an edge type backlight unit.

A liquid crystal display device (LCD), which is advantageous for moving picture display and has a large contrast ratio and is actively used in TVs and monitors, exhibits optical anisotropy and polarization properties of a liquid crystal, And the like.

Such a liquid crystal display device has a liquid crystal panel in which a liquid crystal panel is interposed between two adjacent substrates through a liquid crystal layer as an essential component and changes the alignment direction of the liquid crystal molecules in an electric field in the liquid crystal panel to realize a difference in transmittance do.

However, since the liquid crystal panel does not have its own light emitting element, a separate light source is required to display the difference in transmittance as an image. To this end, a backlight having a light source is disposed on the back surface of the liquid crystal panel.

The backlight unit uses a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp, and a light emitting diode (LED) as a light source.

In particular, LEDs are widely used as light sources for displays, having characteristics such as small size, low power consumption, and high reliability.

Meanwhile, the general backlight unit is divided into a direct type and an edge type depending on the arrangement of the lamps. In the edge type, one or a pair of light sources is divided into one side of the light guide plate and two or two pairs The light source has a structure in which the light sources are disposed on both side portions of the light guide plate, and the direct light type structure has a structure in which several light sources are disposed under the liquid crystal panel.

Here, the direct type type is mainly used in a liquid crystal display device in which brightness is more important than thickness in view of thinness, and an edge type in which a light weight and thin type can be compared with a direct type type is used for a notebook PC or a monitor PC And is mainly used in a liquid crystal display device in which thickness is important.

1 is a cross-sectional view of a liquid crystal display including a backlight unit of a general edge type using an LED as a light source.

As shown in the figure, a liquid crystal display device including a general edge type backlight unit 20 includes a liquid crystal panel 10, a backlight unit 20, a support main 30, a cover bottom 50, 40).

The liquid crystal panel 10 is constituted by first and second substrates 12 and 14 which are in contact with each other with a liquid crystal layer interposed therebetween, which plays a key role in image display.

The backlight unit 20 is provided behind the liquid crystal panel 10.

The backlight unit 20 includes an LED assembly 29 arranged along the longitudinal direction of at least one edge of the support main body 30 and composed of au and a PCB 29b on which a plurality of LEDs 29a and LEDs 29a are mounted, A reflective plate 25 of white or silver color resting on the cover bottom 50 and a light guide plate 23 resting on the reflective plate 25 and an optical sheet 21 located thereon.

The liquid crystal panel 10 and the backlight unit 20 are covered with a top cover 40 covering the upper edge of the liquid crystal panel 10 in a state where the edge is surrounded by the support main 30 having a rectangular frame shape, And the cover bottoms 50 are integrally joined to each other through the support main body 30.

And reference numerals 19a and 19b denote polarizers attached to the front and back surfaces of the liquid crystal panel 10 to control the polarization direction of light, respectively.

At this time, the LED assembly 29 is disposed on one side of the light guide plate 23, and the light is distributed to the entire surface using the light guide plate 23 to supply the surface light source to the liquid crystal panel 10.

A liquid crystal display device including such an edge type backlight unit 20 is limited in terms of weight and thickness as well as in recent enlargement. This is because the light incident from the light-incident portion on one side of the light guide plate 23, The light is not completely transmitted to the light-receiving portion and the brightness and uniformity of light are lowered.

Accordingly, in recent years, the number of the LEDs 29a of the LED assembly 29 has been increased, which causes problems such as cost increase and heat dissipation of the liquid crystal display device, have.

The liquid crystal display device including the backlight unit 20 of the edge-type system diffuses light to the entire surface by using the light guide plate 23 and supplies the surface light source to the liquid crystal panel 10, It is very difficult to supply light to specific areas of the display device.

That is, in the backlight 20 of the edge type, the backlight division driving method is difficult.

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a liquid crystal display device capable of being large-sized and lightweight and thin.

A second object of the present invention is to provide a liquid crystal display device capable of performing local dimming. A third object of the present invention is to improve the contrast ratio and reduce the power consumption of the backlight unit.

The fourth object is to reduce the number of LEDs to reduce the material cost.

According to an aspect of the present invention, there is provided a liquid crystal display comprising: a liquid crystal panel; A light guide plate disposed at a lower portion of the liquid crystal panel and divided into a plurality of regions; And a plurality of LED assemblies positioned on the plurality of divided regions of the light guide plate.

Here, the plurality of divided regions of the light guide plate include the edges of the light guide plate, and the plurality of LED assemblies are disposed to surround the edges of the light guide plate. The LED assembly includes a PCB and a plurality of LEDs, Is bent in a shape corresponding to the edge of the light guide plate.

The PCB has a first bend portion corresponding to a portion of the first side face and a second bend portion corresponding to a portion of the second side face, And a larger number of LEDs are mounted on the first bent portion corresponding to the minor axis of the light guide plate than the second bent portion corresponding to the long axis side of the light guide plate.

In addition, the plurality of LED assemblies are located on the side surfaces of the plurality of divided regions of the light guide plate, and the LED assemblies positioned corresponding to the short axis side of the light guide plate are positioned corresponding to the long axis side of the light guide plate. It includes a large number of LEDs.

Here, grooves or patterns are formed between the plurality of regions on the lower surface of the light guide plate, and the grooves are formed in a V-cut shape from the lower surface toward the upper surface, Respectively.

In addition, a pattern that becomes denser toward the central portion is formed on the lower surface of the light guide plate, and the pattern may be formed of an elliptical pattern, a polygon pattern, a hologram pattern, or a prism pattern ), And a lenticular pattern.

A reflective plate is disposed under the light guide plate, and an optical sheet is disposed on the light guide plate.

As described above, since the LED assembly is positioned corresponding to each region of the light guide plate according to the present invention, it is possible to realize a large size without increasing the cost and power consumption, even though a lightweight and thin edge type backlight unit is used. .

In addition, it is possible to implement a backlight division driving, thereby realizing a lively image. Further, brightness suitable for an image can be adjusted, and an image having a dark brightness can have light of a dark brightness, It is possible to reduce the power consumption of the display device.

1 is a cross-sectional view of a liquid crystal display including a backlight unit of a general edge type using an LED as a light source.
2 is an exploded perspective view schematically showing a liquid crystal display device including an edge type backlight unit according to an embodiment of the present invention.
3A and 3B are perspective views schematically showing a light guide plate and an LED assembly according to a first embodiment of the present invention.
4A to 4B are diagrams for explaining backlight division driving according to the first embodiment of the present invention.
5A and 5B are perspective views schematically illustrating a light guide plate and an LED assembly according to a second embodiment of the present invention.
6A to 6B are diagrams for explaining backlight division driving according to a second embodiment of the present invention;

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

2 is an exploded perspective view schematically showing a liquid crystal display device including an edge-type backlight unit according to an embodiment of the present invention.

As shown in the figure, a liquid crystal display device including an edge type backlight unit includes a liquid crystal panel 110, a backlight unit 120, a support main 150, a cover bottom 170, and a top cover 160 do.

In detail, each of the liquid crystal panels 110 plays a key role in image display, and includes first and second substrates 112 and 114 which are bonded to each other with a liquid crystal layer interposed therebetween.

At this time, on the premise that the liquid crystal panel 110 is of the active matrix type, a plurality of gate lines and data lines intersect on the inner surface of the first substrate 112, which is usually called an array substrate, And a thin film transistor (TFT) is provided at each of the intersections and is connected in a one-to-one correspondence with the transparent pixel electrodes formed in the respective pixels.

On the inner surface of the second substrate 114, which is called a color filter substrate, a color filter of red, green, and blue colors corresponding to each pixel, and a gate electrode, a data line, and a thin film transistor And a black matrix covering the non-display elements of the black matrix.

On the inner surface of the second substrate 114, a transparent common electrode is formed.

A printed circuit board 117 is connected to at least one edge of the liquid crystal panel 110 via a connection member 116 such as a flexible circuit board so that the side surface or the cover bottom 170 ).

Although not clearly shown in the figure, an upper and a lower alignment film (not shown) for determining the initial alignment direction of the liquid crystal are interposed between the two substrates 112 and 114 of the liquid crystal panel 110 and the liquid crystal layer A seal pattern is formed along the edges of both substrates 112 and 114 to prevent leakage of the liquid crystal layer filled therebetween.

Upper and lower polarizers (not shown) are attached to the outer surfaces of the first and second substrates 112 and 114, respectively.

A backlight unit 120 for supplying light is provided on the back surface of the liquid crystal panel 110 so that the difference in transmittance of the liquid crystal panel 110 is externally expressed.

The backlight unit 120 includes a white or silver reflection plate 125, a light guide plate 200 mounted on the reflection plate 125, first to fourth LED assemblies 210a 210b, 210c, and 210d and the optical sheet 121 on the upper side of the light guide plate 200 are sequentially positioned.

The first to fourth LED assemblies 210a, 210b, 210c and 210d include a plurality of LEDs 211a and 211b and a plurality of LEDs 211a and 211b with PCBs 213a and 213b The PCBs 213a and 213b are bent in a substantially A shape so as to correspond to the edges formed by two adjacent side surfaces of the light guide plate 200. [

That is, the PCBs 213a and 213b of the first to fourth LED assemblies 210a, 210b, 210c and 210d are configured to respectively surround the four corners of the light guide plate 200, and the plurality of LEDs 211a and 211b, Are mounted on the PCBs 213a and 213b in the direction toward the light guide plate 200. [

Light emitted from the plurality of LEDs 211a and 211b of the first to fourth LED assemblies 210a to 210d is incident into the light guide plate 200 through the four corners of the light guide plate 200, The light is guided to the wide area of the light guide plate 200 through the light guide plate 200 by total reflection several times.

Then, the light guide plate 200 is repeatedly reflected and transmitted, thereby providing a planar light source toward the liquid crystal panel 110.

The first to fourth LED assemblies 210a, 210b, 210c and 210d located at the four corners of the light guide plate 200 are disposed on the side surfaces 201c, 201d, and 210d of the light guide plate 200 corresponding to the LEDs 211a and 211b, 201e, and 201f, respectively. This is to allow light of uniform luminance to be incident into the light guide plate 200.

Here, the plurality of LEDs 211a and 211b emit white light including an LED chip (not shown) that emits all the RGB colors or emits white light. The plurality of LEDs 211a and 211b emit light having colors of red (R), green (G) and blue (B), respectively. By lighting the plurality of RGB LEDs 211a and 211b at once, May be realized.

The light guide plate 200 may include a pattern 205 of a specific shape on the lower surface thereof to supply a uniform surface light source toward the liquid crystal panel 110.

The light guide plate 200 may have grooves (not shown) crossing the lower surface of the light guide plate 200 from one side to the other side of the light guide plate 200 facing each other, The light guide plate 200 is divided into the first to fourth regions D1, D2, D3, and D4 by the groove (not shown) or the pattern (not shown).

Accordingly, the liquid crystal display of the present invention includes the light guide plate 200 divided into the first to fourth regions D1, D2, D3, and D4, and the first to fourth LED assemblies 200 and 300 disposed at the four corners of the light guide plate 200, (210a, 210b, 210c, 210d).

That is, the liquid crystal display device of the present invention can implement backlight division driving capable of supplying light to specific regions of the liquid crystal panel 110 for more vivid image display.

Accordingly, it is possible to improve the contrast ratio, to realize a lively image, to adjust the brightness suitable for the image, and to have the image having the dark brightness to have the dark brightness, Can be reduced.

I will discuss this in more detail later.

The reflection plate 125 is disposed on the back surface of the light guide plate 200 and reflects light passing through the back surface of the light guide plate 200 toward the liquid crystal panel 110 to improve the brightness of light.

The optical sheet 121 positioned above the light guide plate 200 includes a diffusion sheet and a light condensing sheet.

The diffusion sheet is positioned directly above the light guide plate 200 and serves to adjust the light direction so that the light proceeds toward the light condensing sheet while dispersing the light incident through the light guide plate 200.

The light diffused through the diffusion sheet is condensed in the direction of the liquid crystal panel 110 by the condensing sheet. Therefore, the light passing through the light condensing sheet is almost perpendicular to the liquid crystal panel 110.

Although not shown, a diffusion plate may be further provided between the light guide plate 200 and the diffusion sheet. The diffusion plate is configured to have various haze characteristics according to the light uniformity. In this case, beads or the like, or a fine pattern (not shown) may be formed on the lower surface without including beads.

At this time, the bead is characterized by being able to prevent the light from being partially concentrated by dispersing the light incident on the diffusion plate. In addition, the diffusion plate not including the beads can control the light scattering angle according to the shape of the fine pattern.

As a result, the light is dispersed to prevent the light from being partially concentrated.

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

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, is formed in a rectangular plate shape, do.

A support main body 130 having a rectangular frame shape and mounted on the cover bottom 170 and covering the edges of the liquid crystal panel 110 and the backlight unit 120 is combined with the top cover 140 and the cover bottom 150.

Here, the top cover 140 may be referred to as a case top or a top case, and the support main 130 may be referred to as a guide panel or a main support or a mold frame, and the cover bottom 150 may be referred to as a bottom cover.

Although the liquid crystal display of the present invention uses a lightweight and thin edge type backlight unit 120, it can be increased in size without increasing the cost and power consumption.

That is, the general edge type backlight unit (20 in FIG. 1) is arranged such that the LED assembly (29 in FIG. 1) is disposed at one side of the light guide plate (23 in FIG. 1) However, since the LED assemblies 210a, 210b, 210c, and 210d are positioned corresponding to the four corners of the light guide plate 200, the liquid crystal display device of the present invention can be enlarged without increasing the number of the LEDs 211a and 211b have.

Therefore, it is possible to realize a large size without increasing the cost and increasing the power consumption.

In addition, even though the edge type backlight unit 120 is used, light can be supplied to specific regions of the liquid crystal panel 110, and backlight division driving can be realized. Accordingly, it is possible to improve the contrast ratio, to realize a lively image, and to adjust the brightness suitable for the image, so that the image having the dark brightness has the light of the dark brightness, It is possible to reduce the power consumption of the battery 120.

3A and 3B are perspective views schematically showing a light guide plate and an LED assembly according to a first embodiment of the present invention.

3A, the light guide plate 200 is made of a plastic material such as polymethylmethacrylate (PMMA) which is an acrylic transparent resin, which is one of transparent materials capable of transmitting light, or a plastic material such as polycarbonate : PC) series.

Here, PMMA is an acrylic resin, which is excellent in transparency, weatherability, and colorability, and induces diffusion of light when light is transmitted.

The light guide plate 200 includes a first surface 201a on which light is emitted, a lower surface 201b facing the reflection plate 125 in FIG. 2, and first through fifth surfaces 201a and 201b connected to the upper surface 201a and the lower surface 201b. Four side faces 201c, 201d, 201e, and 201f.

At this time, on the lower surface 201b of the light guide plate 200 of the present invention, grooves (not shown) are formed on the lower surface 201b of the light guide plate 200 from the first side face 201c to the third side face 201e, (Not shown) or a pattern (not shown) that crosses the lower surface 201b of the light guide plate 200 from the second side surface 201d toward the fourth side surface 201f, And the inner area of the light guide plate 200 is defined in a divided manner.

Here, the groove (not shown) may have a V-cut shape from the lower surface 201b of the light guide plate 200 toward the upper surface 201a.

Accordingly, the light guide plate 200 is divided into the first to fourth regions D1, D2, D3, and D4 through a groove (not shown) or a pattern (not shown). At this time, the light guide plate 200 divided into the first to fourth regions D1, D2, D3 and D4 through grooves (not shown) or patterns (not shown) enters into the light guide plate 200 during the backlight division driving It is possible to prevent the light beams from overlapping each other.

The first to fourth LED assemblies 210a, 210b, 210c and 210d are located at four corners of the light guide plate 200 and are divided into first to fourth divided areas D1, D2, D3 and D4 of the light guide plate 200 Respectively.

Each of the first to fourth LED assemblies 210a, 210b, 210c and 210d according to the first embodiment of the present invention includes a first bent portion 213a and a first bent portion 213a, And a second bending portion 213b which is mounted on the first bending portion 213a and the second bending portion 213b of the PCB 213. The PCB 213 has a first bend portion 213b and a second bend portion 213b, And second LEDs 211a and 211b.

The first to fourth LED assemblies 210a, 210b, 210c and 210d are mounted on the PCB 213 of the first LED assembly 210a such that the light emitted from the LEDs 211a and 211b is directed to the side of the light guide plate 200, And the second bent portion 213b of the PCB 213 of the first LED assembly 210a is positioned so as to correspond to the first side face 201c of the light guide plate 200. The first bent portion 213a of the first LED assembly 210a corresponds to the first side face 201c of the light guide plate 200, And the second side surface 201d adjacent to the first side surface 201c.

The second LED assembly 210b is positioned such that the first and second bent portions 213a and 213b of the PCB 213 correspond to the second side face 201d and the third side face 201e of the light guide plate 200, And the first and second bent portions 213a and 213b of the third LED assembly 210c are positioned to correspond to the third and fourth sides 201e and 201f of the light guide plate 200 and the fourth LED assembly 210d are positioned so as to correspond to the fourth and first sides 201f, 201c of the light guide plate 200, respectively.

Light is incident on the first region D1 of the light guide plate 200 through the first LED assembly 210a and incident on the second region D2 of the light guide plate 200 through the second LED assembly 210b. The light enters the fourth region D4 of the light guide plate 200 through the third LED assembly 210c to the third region D3 of the light guide plate 200 and through the fourth LED assembly 210d, .

The light incident on the first to fourth regions D1, D2, D3 and D4 of the light guide plate 200 is reflected by the total reflection areas D1, D2, D3, D3, and D4.

Accordingly, the liquid crystal display of the present invention realizes backlight division driving.

That is, the liquid crystal display device of the present invention can realize backlight division driving capable of supplying light to specific regions of the liquid crystal panel (110 in FIG. 2) for more vivid image display.

Here, the backlight division driving is a driving method in which the area corresponding to the pixel is extinguished while the pixel is responding and the area is lighted after the response is completed. Each area is illuminated only for a predetermined time in each frame, Off.

For example, when the first and second LEDs 211a and 211b mounted on the first LED assembly 210a are lit and light is incident on the first region D1 of the light guide plate 200, The plurality of LEDs 211a and 211b mounted on the assemblies 210b, 210c and 210d can be turned off.

Here, the backlight division driving lights off the LED assemblies 210a, 210b, 210c and 210d located in the area of the light guide plate 200 corresponding to the pixels while the pixels are responding, and after the response is completed, the LED assemblies 210a and 210b The LED assemblies 210a, 210b, 210c, and 210d located in the respective regions D1, D2, D3, and D4 of the light guide plate 200 are driven in one frame for a predetermined period of time And is turned off for the remaining time.

The light guide plate 200 is defined as a plurality of regions D1, D2, D3 and D4 and the LED assemblies 210a, 210b and 210c (corresponding to the regions D1, D2, D3 and D4) And 210d are disposed in the liquid crystal panel (110 of FIG. 2) to perform backlight division driving for each of the regions D1, D2, D3 and D4, The contrast ratio can be improved by brightening the bright image or making the dark image darker by implementing the image 110 of FIG. 2, thereby realizing a lively image.

Further, the brightness suitable for the image can be adjusted, and the image with dark brightness has light of dark brightness, so that the power consumption of the backlight unit (120 of FIG. 2) can be reduced.

The light incident into the light guide plate 200 through the four corners of the light guide plate 200 is guided to the lower surface 201b of the light guide plate 200 divided into the plurality of areas D1, D2, D3, A pattern 205 of a specific shape for making the light incident in the direction of FIG. 2 (110 in FIG. 2) is formed.

The pattern 205 may be formed in various shapes such as an elliptical pattern, a polygon pattern, a hologram pattern, and the like in order to guide light incident into the light guide plate 200 , And the pattern 205 is formed on the lower surface 201b of the light guide plate 200 by a printing method or an injection method.

At this time, the pattern 205 formed on the lower surface 201b of the light guide plate 200 is formed at a low density per unit area as closer to the first to fourth LED assemblies 210a, 210b, 210c, and 210d, It is preferable to form the layer at a high density per unit area toward the center.

That is, the light guide plate 200 forms the pattern 205 densely toward the central portion of the light guide plate 200 irrespective of the first to fourth regions D1, D2, D3, and D4 defined in the light guide plate 200 will be.

The first to fourth LED assemblies 210a, 210b, 210c and 210d located at the four corners of the light guide plate 200 are arranged on the side surfaces 201c, 201d, 201e and 201d of the light guide plate 200, And 201f. This is to allow light of uniform luminance to be incident into the light guide plate 200.

3B, the PCB 213b of the LED assemblies 210a, 210b, 210c, and 210d located on the short axes 201d and 201f of the side surface of the light guide plate 200 is disposed on the long axis of the light guide plate 200 210b, 210c, and 210d of the LEDs 210a, 210b, 210c, and 210d located in the LEDs 201a, 201c, and 201e, so that a greater number of the LEDs 211b are mounted.

This is because the light emitted from the LEDs 211a and 211b located at one side of the light guide plate 200 spreads toward the central portion of the light guide plate 200 and the side faces 201d and 201f corresponding to the short axis of the light guide plate 200 The distance of the light emitted from the LED 211b located in the center of the light guide plate 200 toward the central portion of the light guide plate 200 is smaller than that of the LED 211a positioned corresponding to the side surfaces 201c and 201e corresponding to the long axis of the light guide plate 200, Because the light emitted from the light guide plate 200 is longer than the distance traveled toward the center of the light guide plate 200.

Therefore, light of uniform brightness can be incident into the light guide plate 200. [

Although not shown, the light efficiency of the LED 211b positioned corresponding to the short sides of the light guide plate 201d, 201f corresponds to the long sides of the light guide plate 201a, 201e corresponding to the long sides of the light guide plate, ) Can be used.

4A to 4B are views for explaining backlight division driving according to the first embodiment of the present invention.

The light guide plate 200 defined by dividing the first to fourth regions D1, D2, D3, and D4 through a groove (not shown) or a pattern (not shown) of the lower surface (201b of FIG. 3B) And first to fourth LED assemblies 210a, 210b, 210c, and 210d in which a plurality of LEDs 211 are mounted so as to face the four corners of the light guide plate 200. [

At this time, the first to fourth LED assemblies 210a, 210b, 210c and 210d are divided and driven so that light enters into the light guide plate 200 through the four corners of the light guide plate 200. [

Therefore, the present invention can improve the contrast ratio by making the bright image brighter or darker by darkening the backlight by driving the divided backlight, thereby realizing a lively image.

That is, in order to brighten the image implemented in the liquid crystal panel 110 (FIG. 2) corresponding to the first and fourth regions D1 and D4 of the light guide plate 200 as shown in FIG. 4A, The LEDs 211 of the first LED assembly 210a and the LEDs 211 of the fourth LED assembly 210d are simultaneously turned on to enter the first and fourth regions D1 and D4 of the light guide plate 200. At this time, The LEDs 211 of the LED assemblies 210b and 210c are turned off to prevent light from being incident on the second and third regions D2 and D3 of the light guide plate 200. [

2) corresponding to the first and fourth regions D1 and D4 of the light guide plate 200 are brightly displayed and the second and third regions D1 and D2 of the light guide plate 200, (110 in FIG. 2) corresponding to the first and fourth regions D1 and D4 of the light guide plate 200 is implemented in the liquid crystal panel (110 in FIG. 2) corresponding to the first and second regions D2 and D3 The contrast ratio of the image can be improved.

Only the LEDs 211 of the second and third LED assemblies 210b and 210c are turned on to emit light to the inside of the second and third regions D2 and D3 of the light guide plate 200, The image formed on the liquid crystal panel 110 of FIG. 2 corresponding to the second and third regions D2 and D3 of the light guide plate 200 is brightly displayed and the first and second regions D2 and D3 of the light guide plate 200 are illuminated. 2) corresponding to the second and third regions D2 and D3 of the light guide plate 200 and the liquid crystal panel 110 corresponding to the four regions D1 and D4 The contrast ratio of the image can be improved.

This makes it possible to realize a vivid image.

Particularly, the light incident into the light guide plate 200 for each of the first to fourth LED assemblies 210a, 210b, 210c, and 210d is not overlapped with each other inside the light guide plate 200, so that a more vivid image can be realized.

5A and 5B are perspective views schematically showing a light guide plate and an LED assembly according to a second embodiment of the present invention.

5A, the light guide plate 200 includes an upper surface 201a on which light is emitted, a lower surface 201b facing the reflection plate 125 in FIG. 2, and upper and lower surfaces 201a and 201b. 201d, 201e, and 201f connected to the first to fourth sides 201c, 201d, 201e, and 201f.

At this time, on the lower surface 201b of the light guide plate 200 of the present invention, grooves (not shown) are formed on the lower surface 201b of the light guide plate 200 from the first side face 201c to the third side face 201e, (Not shown) or a pattern (not shown) that crosses the lower surface 201b of the light guide plate 200 from the second side surface 201d toward the fourth side surface 201f, And the inner area of the light guide plate 200 is defined in a divided manner.

Here, the groove (not shown) may have a V-cut shape from the lower surface 201b of the light guide plate 200 toward the upper surface 201a.

Accordingly, the light guide plate 200 is divided into the first to fourth regions D1, D2, D3, and D4 through a groove (not shown) or a pattern (not shown). At this time, the light guide plate 200 divided into the first to fourth regions D1, D2, D3 and D4 through grooves (not shown) or patterns (not shown) enters into the light guide plate 200 during the backlight division driving It is possible to prevent the light beams from overlapping each other.

At this time, the first to fourth LED assemblies 310a, 310b, 310c, and 310d are positioned corresponding to the first to fourth regions D1, D2, D3, and D4 of the light guide plate 200, The four LED assemblies 310a, 310b, 310c, and 310d are positioned on the side surfaces of the respective regions D1, D2, D3, and D4 of the light guide plate 200, respectively.

Each of the first to fourth LED assemblies 310a, 310b, 310c, and 310d according to the second embodiment of the present invention includes a plurality of LEDs 311, As shown in FIG.

Light is incident on the first region D1 of the light guide plate 200 through the first LED assembly 310a and incident on the second region D2 of the light guide plate 200 through the second LED assembly 310b. The light enters the fourth region D4 of the light guide plate 200 through the third LED assembly 310c into the third region D3 of the light guide plate 200 and through the fourth LED assembly 310d through the third LED assembly 310c, .

The light incident on the first to fourth regions D1, D2, D3 and D4 of the light guide plate 200 is reflected by the total reflection areas D1, D2, D3, D3, and D4.

Accordingly, the liquid crystal display device of the present invention can implement backlight division driving capable of supplying light to specific regions of the liquid crystal panel (110 in FIG. 2) for more vivid image display.

That is, the light guide plate 200 is defined as a plurality of regions D1, D2, D3, and D4, and the LED assemblies 310a, 310b, and 310c correspond to the plurality of regions D1, D2, D3, and D4 of the light guide plate 200, 310c and 310d are positioned so as to perform backlight division driving for each of the regions D1, D2, D3 and D4 so that only the light emitted for each region is supplied to a specific region of the liquid crystal panel The contrast ratio can be improved by brightening the bright image or making the dark image darker by implementing the image (110 of FIG. 2), thereby realizing a lively image.

In addition, brightness suitable for the image can be adjusted, and the image with dark brightness has light of dark brightness, so that the power consumption of the backlight unit (120 in FIG. 2) can be reduced.

The light incident on the lower surface 201b of the light guide plate 200 divided into the plurality of regions D1, D2, D3 and D4 is incident on the light guide plate 200 through the four corners of the light guide plate 200, A pattern 205 of a specific shape for making the light incident in the direction of FIG. 2 (110 in FIG. 2) is formed.

At this time, the pattern 205 formed on the lower surface 201b of the light guide plate 200 is formed at a low density per unit area as closer to the first to fourth LED assemblies 210a, 210b, 210c, and 210d, It is preferable to form the layer at a high density per unit area toward the center.

The LEDs 311 mounted on the first to fourth LED assemblies 310a, 310b, 310c, and 310d corresponding to the sides of the regions D1, D2, D3, and D4 of the light guide plate 200, (201c, 201d, 201e, and 201f) of the light emitting device (200). This is to allow light of uniform luminance to be incident into the light guide plate 200.

5b, the LED assemblies 310b and 310d located on the short axes 201d and 201f of the side surface of the light guide plate 200 are connected to the LED assemblies 310b and 310d located on the long axes 201c and 201e of the light guide plate 200, 310a, and 310c, as shown in FIG.

This is because the light emitted from the LED 311 located on one side of the light guide plate 200 is reflected on the side surfaces 201d and 201f corresponding to the short axis of the light guide plate 200 in the process of spreading toward the center of the light guide plate 200 The distance that the light emitted from the corresponding LED 311 travels toward the central portion of the light guide plate 200 is emitted from the LED 311 positioned corresponding to the side surfaces 201c and 201e corresponding to the long axis of the light guide plate 200 This is because the light emitted from the light guide plate 200 is longer than the light propagated toward the center of the light guide plate 200.

Therefore, light of uniform brightness can be incident into the light guide plate 200. [

Although not shown, the light efficiency of the LED 311 corresponding to the short side of the light guide plate 200 corresponds to the side faces 201c and 201e corresponding to the long axis of the light guide plate 200 It is also possible to use a higher LED 311 than the LED 311 located at the same position.

6A and 6B are views for explaining backlight division driving according to the second embodiment of the present invention.

The light guide plate 200 is divided into the first to fourth regions D1, D2, D3 and D4 through a groove (not shown) or a pattern (not shown) of the lower surface (201b in FIG. 5B) The first to fourth LED assemblies 310a, 310b, 310c, and 310d are positioned corresponding to the sides of the light guide plate 200 and the areas D1, D2, D3, and D4, respectively.

At this time, the first to fourth LED assemblies 310a, 310b, 310c, and 310d are divided and driven so that light is incident on the respective regions D1, D2, D3, and D4 of the light guide plate 200. [

Therefore, the present invention can improve the contrast ratio by making the bright image brighter or darker by darkening the backlight by driving the divided backlight, thereby realizing a lively image.

That is, in order to brighten the image implemented in the liquid crystal panel (110 in FIG. 2) corresponding to the first and third regions D1 and D3 of the light guide plate 200 as shown in FIG. 6A, The LEDs 311 of the third LED assembly 310c and the LEDs 311 of the third LED assembly 310c are simultaneously turned on to enter the first and third regions D1 and D3 of the light guide plate 200. At this time, The LEDs 311 of the LED assemblies 310b and 310d are turned off to prevent light from being incident on the second and fourth regions D2 and D4 of the light guide plate 200. [

2) corresponding to the first and third regions D1 and D3 of the light guide plate 200 are brightly displayed and the second and fourth regions D1 and D2 of the light guide plate 200, (110 in FIG. 2) corresponding to the first and third regions D1 and D3 of the light guide plate 200 is implemented in the liquid crystal panel 110 corresponding to the first and second regions D2 and D4 The contrast ratio of the image can be improved.

The LEDs 311 of the second and fourth LED assemblies 310b and 310d are turned on to emit light in the second and fourth regions D2 and D4 of the light guide plate 200, The image formed on the liquid crystal panel 110 of FIG. 2 corresponding to the second and fourth regions D2 and D4 of the light guide plate 200 is brightly displayed and the first and second regions D2 and D4 of the light guide plate 200 are illuminated. 2) corresponding to the second and fourth regions D2 and D4 of the light guide plate 200 and the liquid crystal panel 110 corresponding to the three regions D1 and D3 (110 of FIG. 2) The contrast ratio of the image can be improved.

This makes it possible to realize a vivid image.

As described above, although the liquid crystal display device of the present invention uses a lightweight and thin edge type backlight unit (120 in FIG. 2), the size can be increased without increasing the cost and power consumption.

Further, even though the edge type backlight unit (120 in FIG. 2) is used, light can be supplied to specific areas of the liquid crystal panel (110 in FIG. 2), and backlight division driving can be realized. Accordingly, it is possible to improve the contrast ratio, to realize a lively image, and to adjust the brightness suitable for the image, so that the image having the dark brightness has the light of the dark brightness, (120 in Fig. 2) can be reduced.

The present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

200: light guide plate, 201c, 201d, 201e, 201f: first to fourth sides
210a, 210b, 210c, 210d: first to fourth LED assemblies
211a, 211b: first and second LEDs 213a, 213b: first and second bent portions (PCB)
D1, D2, D3, and D4: first to fourth regions

Claims (12)

A liquid crystal panel;
A liquid crystal panel disposed on a lower surface of the liquid crystal panel,
A light guide plate divided into a plurality of regions having a plurality of vertically bent corners;
A groove or pattern dividing the plurality of divided areas across the lower surface of the light guide plate in the short axis direction and the long axis direction;
And a plurality of LED assemblies positioned corresponding to each of the plurality of divided regions,
Each of the plurality of LED assemblies includes a first bent portion corresponding to a part of the first side portion of the corresponding divided region and a second bent portion corresponding to a portion of the second side portion of the divided region, The LED comprising a plurality of LEDs mounted on the first bending portion, the PCB comprising a second bent portion corresponding to the first bent portion,
The LED of the first bent portion has a higher light efficiency than the LED of the second bent portion
Liquid crystal display device.

delete A liquid crystal panel;
A liquid crystal panel disposed on a lower surface of the liquid crystal panel,
A light guide plate divided into a plurality of regions having a plurality of vertically bent corners;
A groove or pattern dividing the plurality of divided areas across the lower surface of the light guide plate in the short axis direction and the long axis direction;
And a plurality of LED assemblies positioned corresponding to each of the plurality of divided regions,
Wherein the plurality of LED assemblies are located only at the second side portion of the odd-numbered divided regions, and the remaining LED assemblies are located only at the first side portion of the neighboring even-numbered divided regions, Each of the LED assemblies has a larger number of LEDs than the LED assembly located in the odd-numbered division region,
Wherein the LED assembly located in the even-numbered divided region has a higher light efficiency than the LED of the LED assembly located in the odd-
Liquid crystal display device.
delete The method according to claim 1 or 3,
Wherein the groove is formed so as to intersect the lower surface in a V-cut shape from the lower surface toward the upper surface of the light guide plate.
The method according to claim 1 or 3,
And a pattern that becomes denser toward the center portion is formed on the lower surface.
The method according to claim 6,
Wherein the pattern is one selected from the group consisting of an elliptical pattern, a polygon pattern, a hologram pattern, a prism pattern, and a lenticular pattern.
The method according to claim 1 or 3,
Wherein a reflective plate is disposed on a lower portion of the light guide plate, and an optical sheet is disposed on an upper portion of the light guide plate. delete delete delete delete

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