KR20120116576A - Liquid crystal display device - Google Patents

Liquid crystal display device Download PDF

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Publication number
KR20120116576A
KR20120116576A KR1020110034091A KR20110034091A KR20120116576A KR 20120116576 A KR20120116576 A KR 20120116576A KR 1020110034091 A KR1020110034091 A KR 1020110034091A KR 20110034091 A KR20110034091 A KR 20110034091A KR 20120116576 A KR20120116576 A KR 20120116576A
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KR
South Korea
Prior art keywords
guide plate
light guide
liquid crystal
light
pattern
Prior art date
Application number
KR1020110034091A
Other languages
Korean (ko)
Inventor
김도윤
한상호
Original Assignee
엘지디스플레이 주식회사
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Priority to KR1020110034091A priority Critical patent/KR20120116576A/en
Publication of KR20120116576A publication Critical patent/KR20120116576A/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0015—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0016—Grooves, prisms, gratings, scattering particles or rough surfaces
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0075—Arrangements of multiple light guides
    • G02B6/0078—Side-by-side arrangements, e.g. for large area displays
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133524—Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side

Abstract

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device including an edge type backlight unit.
A feature of the present invention is that the LED assembly is located corresponding to each area of the light guide plate, so that even when using a lightweight and thin edge type backlight unit, it is possible to realize a large size without increasing the cost and power consumption.
In addition, it is possible to implement backlight division driving, thereby realizing a vivid image, and also to adjust the brightness according to the image, so that the image having a dark brightness has a light of dark brightness, power consumption of the backlight unit Can be reduced.

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 including an edge type backlight unit.

Liquid crystal display devices (LCDs), which are used for TVs and monitors due to their high contrast ratio and are advantageous for displaying moving images, are characterized by optical anisotropy and polarization of liquid crystals. The principle of image implementation by

Such a liquid crystal display is an essential component of a liquid crystal panel bonded through a liquid crystal layer between two side-by-side substrates, and realizes a difference in transmittance by changing an arrangement direction of liquid crystal molecules with an electric field in the liquid crystal panel. do.

However, since the liquid crystal panel does not have its own light emitting element, a separate light source is required 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.

Among them, LEDs are particularly widely used as light sources for displays with features such as small size, low power consumption, and high reliability.

Meanwhile, a general backlight unit is classified into a direct type method and an edge type method according to the arrangement of lamps. In the edge type method, one or a pair of light sources is provided with one or two or two pairs of light guide plates. The light source has a structure in which both sides of the light guide plate are disposed, and the direct type has a structure in which several light sources are disposed below the liquid crystal panel.

Here, the direct type has a limitation in thinning, and is mainly used in a liquid crystal display device in which brightness is more important than the thickness of the screen, and the edge type which is lighter and thinner than the direct type is such as a notebook PC or a monitor PC. It is mainly used in liquid crystal displays where thickness is important.

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

As shown in the drawing, the LCD including the backlight unit 20 of the general edge type includes a liquid crystal panel 10 and a backlight unit 20, a support main 30, a cover bottom 50, and a top cover ( 40).

The liquid crystal panel 10 is a part that plays a key role in image expression and is composed of first and second substrates 12 and 14 bonded to each other with a liquid crystal layer interposed therebetween.

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

The backlight unit 20 includes an LED assembly 29 including a plurality of LEDs 29a and a PCB 29b on which the LEDs 29a are arranged, arranged along at least one edge of the support main 30. A white or silver reflector 25 mounted on the cover bottom 50, a light guide plate 23 seated on the reflector 25, and an optical sheet 21 positioned thereon.

The liquid crystal panel 10 and the backlight unit 20 have a top cover 40 surrounding the top edge of the liquid crystal panel 10 and a back surface of the backlight unit 20 in a state where the edges are surrounded by the support main 30 having a rectangular frame shape. Cover cover 50 to cover each is coupled in front and rear are integrated through the support main 30 as a medium.

In addition, reference numerals 19a and 19b denote polarizers attached to the front and rear 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 to distribute the light to the entire surface using the light guide plate 23 to supply the surface light source to the liquid crystal panel 10.

The liquid crystal display device including the edge type backlight unit 20 has a limitation in size and size, which is recently required with light weight and thinness, which means that the light incident from the light incident part on one side of the light guide plate 23 has a long distance. This is because the luminance and uniformity of the light are deteriorated since the light is not completely reached to the incident light part.

Therefore, in recent years, the number of LEDs 29a of the LED assembly 29 is increased, which causes a cost increase problem and a heat dissipation problem of the liquid crystal display, and further increases power consumption. have.

In addition, the liquid crystal display device including the edge type backlight unit 20 uses the light guide plate 23 to disperse light to the entire surface to supply a surface light source to the liquid crystal panel 10, thereby providing a liquid crystal panel 10. It is very difficult to supply light to specific areas of

That is, the edge type backlight 20 is difficult to divide the backlight driving method.

The present invention has been made in view of the above-mentioned problems, and a first object of the present invention is to provide a liquid crystal display device that can be enlarged and lightly thinned.

In addition, a second object of the present invention is to provide a liquid crystal display device capable of local dimming backlight, thereby improving the contrast ratio and reducing the power consumption of the backlight unit.

In addition, 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 positioned under the liquid crystal panel and divided into a plurality of regions; Provided is a liquid crystal display including a plurality of LED assemblies, each of which is positioned for each of a plurality of divided regions of the light guide plate.

In this case, the plurality of divided regions of the light guide plate may include edges of the light guide plate, and the plurality of LED assemblies may be positioned to surround the edges of the light guide plate, and the LED assembly may include a PCB and a plurality of LEDs. Is bent in a shape to correspond to the edge of the light guide plate.

The first and second side surfaces of the light guide plate may be adjacent to each other, and the PCB may include a first bent portion corresponding to a portion of the first side and a second bent portion corresponding to a portion of the second side. In the first bent portion corresponding to the short axis side of the light guide plate, a greater number of LEDs are mounted 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 side surfaces of the plurality of divided regions of the light guide plate, and the LED assembly corresponding to the short axis side of the light guide plate is more than the LED assembly positioned corresponding to the long axis side of the light guide plate. It contains a large number of LEDs.

Here, a groove or a pattern is formed in the lower surface of the light guide plate between the plurality of regions, and the groove is formed in a V-cut shape from the lower surface toward the upper surface to form the lower surface of the light guide plate. It is formed to traverse.

In addition, the lower surface of the light guide plate is formed a denser pattern toward the center, the pattern is an elliptical pattern (elliptical pattern), polygonal pattern (polygon pattern), hologram pattern (hologram pattern) or prism pattern (prism pattern) ), One selected from the form of a lenticular pattern.

In addition, a reflector is positioned below the light guide plate, and an optical sheet is positioned above the light guide plate.

As described above, by placing the LED assembly corresponding to each area of the light guide plate according to the present invention, even if using a lightweight and thin edge type backlight unit, it is possible to implement a large size without increasing the cost and power consumption There is.

In addition, backlight division driving can be implemented, and thus, a vivid image can be realized, and brightness can be adjusted according to the image, so that an image having a dark brightness has light having a dark brightness, thereby providing a backlight unit. There is an effect that can reduce the power consumption of.

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

As illustrated, the LCD including the edge type backlight unit includes a liquid crystal panel 110, a backlight unit 120, and a support main 150, a cover bottom 170, and a top cover 160. do.

Looking at each of these in detail, the liquid crystal panel 110 is a part that plays a key role of the image expression, and includes the first and second substrates 112 and 114 bonded to each other with the liquid crystal layer interposed therebetween.

At this time, assuming that the liquid crystal panel 110 is an active matrix type, a plurality of gate lines and data lines intersect on the inner surface of the first substrate 112, which is commonly referred to as an array substrate, although not clearly shown in the drawing. ) And thin film transistors (TFTs) are provided at each crossing point and are connected one-to-one with the transparent pixel electrodes formed in each pixel.

In addition, the inner surface of the second substrate 114 called the color filter substrate is a color filter of red, green, and blue colors, and each of them corresponds to each pixel, and includes a gate line, a data line, a thin film transistor, and the like. A black matrix is provided that obscures the non-display elements of.

The inner surface of the second substrate 114 is provided with a transparent common electrode covering them.

A printed circuit board 117 is connected through at least one edge of the liquid crystal panel 110 via a connecting member 116 such as a flexible circuit board, so that the side surface or cover cover 170 of the support main 150 is modularized. ) It is flipped to the back and adhered.

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

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

The back of the liquid crystal panel 110 is provided with a backlight unit 120 for supplying light, so that the difference in transmittance of the liquid crystal panel 110 is expressed to the outside.

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

The first to fourth LED assemblies 210a, 210b, 210c, and 210d may include a plurality of LEDs 211a and 211b and PCBs 213a and 213b mounted at a predetermined interval apart from each other. The PCBs 213a and 213b are bent in a roughly a shape to correspond to corners formed by two neighboring 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 respectively have four structures surrounding four corners of the light guide plate 200 and include a plurality of LEDs 211a and 211b. Is mounted on the PCBs 213a and 213b in a direction toward the light guide plate 200.

Accordingly, light emitted from the plurality of LEDs 211a and 211b of the first to fourth LED assemblies 210a, 210b, 210c, and 210d is incident into the light guide plate 200 through four corners of the light guide plate 200. As the light guide plate 200 proceeds through the total reflection several times, the light guide plate 200 is spread evenly over a wide area of the light guide plate 200.

In addition, the light guide plate 200 repeats reflection and transmission, thereby providing a surface light source toward the liquid crystal panel 110.

In this case, the first to fourth LED assemblies 210a, 210b, 210c, and 210d disposed at four corners of the light guide plate 200 may have side surfaces 201c, 201d, and 201d of the light guide plate 200 corresponding to the number of LEDs 211a and 211b. 201e, 201f) is preferably formed differently. This is to allow light of uniform brightness to enter the light guide plate 200.

Here, the plurality of LEDs 211a and 211b emits white light forward, including an LED chip (not shown) that emits all of the colors of RGB or emits white light. In addition, the plurality of LEDs 211a and 211b emit light having the colors of red (R), green (G), and blue (B), respectively, and the color is mixed by lighting the plurality of RGB LEDs 211a and 211b at once. It is also possible to implement the white light by.

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

At this time, the light guide plate 200 of the present invention is formed with a groove (not shown) crossing the lower surface of the light guide plate 200 toward one side from the other side of the light guide plate 200 facing each other, or a pattern (not shown) The light guide plate 200 is divided into 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 first and fourth LED assemblies positioned at four corners of the light guide plate 200 and the light guide plate 200 divided into the first to fourth regions D1, D2, D3, and D4. The backlight division driving is implemented through 210a, 210b, 210c, and 210d.

That is, the liquid crystal display of the present invention can implement a backlight division driving that can supply light for each specific area of the liquid crystal panel 110 for a more vibrant image representation.

As a result, the contrast ratio can be improved, a vivid image can be realized, and brightness can be adjusted according to the image, so that an image having a dark brightness has light of dark brightness, thereby providing a backlight unit 120. ) Can reduce power consumption.

We will discuss this in more detail later.

The reflection plate 125 is positioned on the rear surface of the light guide plate 200 to reflect the light passing through the rear surface of the light guide plate 200 toward the liquid crystal panel 110 to improve the brightness of the light.

The optical sheet 121 positioned on the light guide plate 200 includes a diffusion sheet, a light collecting sheet, and the like.

The diffusion sheet is positioned directly on the light guide plate 200, and serves to adjust the direction of light to propagate toward the light collecting sheet while dispersing 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.

On the other hand, although not shown may be further provided with a diffusion plate between the light guide plate 200 and the diffusion sheet, the diffusion plate is configured to have a variety of haze (haze) characteristics according to the light uniformity, wherein the haze value of the diffuser plate (bead) It may be configured to include a light diffusing component such as a bead) or to form a fine pattern (not shown) on the lower surface without including the beads.

At this time, the bead has a feature that can prevent the light is partially concentrated by dispersing the light incident on the diffusion plate. In addition, the diffusion plate that does not contain beads can adjust 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 the top cover 140, the support main 130, and the cover bottom 150. The top cover 140 is the top and side surfaces of the liquid crystal panel 110. A rectangular frame having a cross section bent in a shape of “a” so as to cover an edge thereof is configured to open an entire surface of the top cover 140 to display an image implemented in the liquid crystal panel 110.

In addition, the cover bottom 150 on which the liquid crystal panel 110 and the backlight unit 120 are mounted, and which is the basis for assembling the entire apparatus of the liquid crystal display device, has a rectangular plate shape and is formed by bending both edges in the longitudinal direction thereof to a predetermined height. do.

A support main 130 having a rectangular frame shape seated on the cover bottom 170 and surrounding 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, the support main 130 may be referred to as a guide panel or a main support, and a mold frame, and the cover bottom 150 may be referred to as a bottom cover.

The liquid crystal display of the present invention can realize a large size without increasing the cost and power consumption even when using the lightweight and thin edge type backlight unit 120.

That is, in the general edge type backlight unit (20 of FIG. 1), the LED assembly (29 of FIG. 1) is disposed on one side of the light guide plate (23 of FIG. 1), so that the light does not completely reach the incoming light incident part to realize the enlargement. In the liquid crystal display of the present invention, the LED assemblies 210a, 210b, 210c, and 210d are located at four corners of the light guide plate 200, thereby increasing the size of the LEDs 211a and 211b without increasing the number of LEDs 211a and 211b. have.

Therefore, it is possible to realize the enlargement without increasing the cost and increasing the power consumption.

In addition, even when the edge type backlight unit 120 is used, light may be supplied to each specific area of the liquid crystal panel 110, thereby implementing backlight division driving. Through this, the contrast ratio can be improved, a vivid image can be realized, and brightness can be adjusted according to the image, so that the image having a dark brightness has light of dark brightness, thereby providing a backlight unit. The power consumption of 120 can be reduced.

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

As shown in FIG. 3A, the light guide plate 200 is made of a plastic material such as polymethylmethacrylate (PMMA) or polycarbonate, which is an acrylic transparent resin, which is one of transparent materials capable of transmitting light. : It is produced in flat type by PC) series.

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

The light guide plate 200 may include first and second surfaces connected to the upper surface 201a through which light is emitted, the lower surface 201b facing the reflector plate 125 of FIG. 2, and the upper surface 201a and the lower surface 201b. It consists of four sides 201c, 201d, 201e, and 201f.

At this time, the lower surface 201b of the light guide plate 200 of the present invention is a groove (not shown) crossing the lower surface 201b of the light guide plate 200 toward the third side surface 201e from the first side surface 201c facing each other. Or a pattern (not shown) is formed, and a groove (not shown) or pattern (not shown) is intersected across the lower surface 201b of the light guide plate 200 from the second side surface 201d to the fourth side surface 201f. ) Is formed to divide and define an inner region of the light guide plate 200.

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

Therefore, the light guide plate 200 is divided into first to fourth regions D1, D2, D3, and D4 through grooves (not shown) or patterns (not shown). In this case, 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) is incident into the light guide plate 200 during backlight division driving. The light can be prevented from overlapping each other.

In addition, the first to fourth LED assemblies 210a, 210b, 210c, and 210d are positioned at four corners of the light guide plate 200 to divide the first to fourth regions D1, D2, D3, and D4 of the light guide plate 200. ), Respectively.

Looking at this in more detail, each of the first to fourth LED assembly (210a, 210b, 210c, 210d) according to the first embodiment of the present invention is perpendicular to the first bent portion (213a) and the first bent portion (213a) The PCB 213 which is composed of a second bent portion 213b and is formed in an A shape, and a first mounted on the first bent portion 213a and the second bent portion 213b of the PCB 213, respectively. And second LEDs 211a and 211b.

The first to fourth LED assemblies 210a, 210b, 210c, and 210d may include the PCB 213 of the first LED assembly 210a such that light emitted from the LEDs 211a and 211b is directed toward the side of the light guide plate 200. The first bent portion 213a of the light guide plate 200 is positioned to correspond to the first side 201c of the light guide plate 200, and the second bent portion 213b of the PCB 213 of the first LED assembly 210a is formed of the light guide plate 200. It is positioned to correspond to the first side (201c) and the second side (201d) neighboring.

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 201d and the third side 201e of the light guide plate 200. The first and second bent portions 213a and 213b of the third LED assembly 210c may be positioned to correspond to the third and fourth side surfaces 201e and 201f of the light guide plate 200. 210d is positioned to correspond to the fourth and first side surfaces 201f and 201c of the light guide plate 200.

Accordingly, light is incident on the first region D1 of the light guide plate 200 through the first LED assembly 210a, and the second region D2 of the light guide plate 200 is passed through the second LED assembly 210b. For example, light is incident to the third region D3 of the light guide plate 200 through the third LED assembly 210c and to the fourth region D4 of the light guide plate 200 through the fourth LED assembly 210d. Let's go.

The light incident on the first to fourth regions D1, D2, D3, and D4 of the light guide plate 200 is reflected in each of the regions D1, D2, D3, D4) will proceed inside.

As a result, the liquid crystal display of the present invention implements backlight division driving.

That is, the liquid crystal display device of the present invention can implement backlight division driving that can supply light for each specific area of the liquid crystal panel (110 of FIG. 2) for a more vibrant image representation.

Here, the backlight division driving is a driving method of turning off the area corresponding to the pixel while the pixel is responding and lighting the area after the response is completed. It goes out.

For example, in the process of injecting light into the first region D1 of the light guide plate 200 by turning on the first and second LEDs 211a and 211b mounted on the first LED assembly 210a, the second to fourth LEDs may be used. The plurality of LEDs 211a and 211b mounted in the assemblies 210b, 210c and 210d may be turned off.

Here, the backlight division driving turns off the LED assemblies 210a, 210b, 210c, and 210d located in the region 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 are completed. LED 210 210a, 210b, 210c, and 210d located in each of the regions D1, D2, D3, and D4 of the light guide plate 200 in a driving manner to turn on the light sources 210c and 210d. Only lights up and goes out for the rest of the time.

In this way, 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 correspond to the plurality of regions D1, D2, D3, and D4 of the light guide plate 200, respectively. , 210d) to perform backlight division driving for each of the regions D1, D2, D3, and D4, thereby supplying only the light emitted for each region to a specific region of the liquid crystal panel 110 of FIG. Contrast ratio can be improved by making a bright image brighter or a dark image darker in the image implemented by 110 of FIG. 2, thereby realizing a vivid image.

In addition, the brightness suitable for the image can be adjusted, so that the image having a dark brightness can have a light of dark brightness, thereby reducing the power consumption of the backlight unit (120 of FIG. 2).

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

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

In this case, the pattern 205 formed on the lower surface 201b of the light guide plate 200 is formed at a lower density per unit area as the first to fourth LED assemblies 210a, 210b, 210c, and 210d are closer to each other. It is desirable to form at a higher density per unit area toward the center.

That is, the light guide plate 200 densely forms the pattern 205 toward the center of the light guide plate 200 regardless 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 positioned at four corners of the light guide plate 200 may have side surfaces 201c, 201d, 201e, and 201e of the light guide plate 200 corresponding to the number of LEDs 211. It is preferable to form differently according to 201f). This is to allow light of uniform brightness to enter the light guide plate 200.

That is, as illustrated in FIG. 3B, the PCB 213b of the LED assemblies 210a, 210b, 210c, and 210d positioned on the short axis 201d and 201f among the side surfaces of the light guide plate 200 may have the long axis 201c of the light guide plate 200. 201e is formed longer than the length of the PCB 213b of the LED assemblies 210a, 210b, 210c, and 210d located in the 201e, so that a larger number of LEDs 211b are mounted.

This is because the light emitted from the LEDs 211a and 211b positioned at one side of the light guide plate 200 spreads toward the center of the light guide plate 200, and thus the side surfaces 201d and 201f corresponding to the short axis of the light guide plate 200. The distance from which the light emitted from the LED 211b positioned in correspondence to the center of the light guide plate 200 travels is 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 is longer than the distance traveling toward the center of the light guide plate 200.

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

Although not shown, the light efficiency of the LED 211b corresponding to the side surfaces 201d and 201f corresponding to the short axis of the light guide plate is located in correspondence with the side surfaces 201c and 201e corresponding to the long axis of the light guide plate. It is also possible to use higher than).

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

As illustrated, 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 mounted with a plurality of LEDs 211 to face four corners of the light guide plate 200.

In this case, the first to fourth LED assemblies 210a, 210b, 210c, and 210d are dividedly driven to allow light to enter the light guide plate 200 through four corners of the light guide plate 200.

Accordingly, the present invention can improve the contrast ratio by brightening a bright image or by darkening a dark image by driving backlight division, thereby realizing a vivid image.

That is, as shown in FIG. 4A, in order to brighten an image embodied in the liquid crystal panel (110 of FIG. 2) corresponding to the first and fourth regions D1 and D4 of the light guide plate 200, the first LED assembly may be brighter. At the same time, the LEDs 211 of the 210a and the fourth LED assembly 210d are turned on to inject light into the first and fourth regions D1 and D4 of the light guide plate 200. The LEDs 211 of the LED assemblies 210b and 210c are turned off so that light does not enter the second and third regions D2 and D3 of the LGP 200.

As a result, an image implemented in the liquid crystal panel (110 of FIG. 2) corresponding to the first and fourth regions D1 and D4 of the light guide plate 200 is brightly represented, and the second and third regions of the light guide plate 200 are represented. An image implemented in the liquid crystal panel (110 of FIG. 2) corresponding to (D2 and D3) is implemented in the liquid crystal panel (110 of FIG. 2) corresponding to the first and fourth regions D1 and D4 of the light guide plate 200. The contrast ratio of the image can be improved by being darker than the image.

Alternatively, as shown in FIG. 4B, only the LEDs 211 of the second and third LED assemblies 210b and 210c are turned on, so that light is emitted inside the second and third regions D2 and D3 of the light guide plate 200. By making the light incident on the light guide plate 200, the image implemented in 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 represented brightly, and the first and the first light guide plate 200 are represented. An image implemented in the liquid crystal panel 110 (in FIG. 2) corresponding to the four regions D1 and D4 may include a liquid crystal panel (110 in FIG. 2) corresponding to the second and third regions D2 and D3 of the light guide plate 200. By expressing darker than the image implemented in the, it is possible to improve the contrast ratio of the image.

Through this, a lively image can be realized.

In particular, the light incident on the light guide plate 200 for each of the first to fourth LED assemblies 210a, 210b, 210c, and 210d may not overlap each other in the light guide plate 200, thereby realizing a more vibrant image.

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

As shown in FIG. 5A, the light guide plate 200 includes an upper surface 201a through which light is emitted, a lower surface 201b facing the reflector plate 125 of FIG. 2, and an upper surface 201a and a lower surface 201b. And first to fourth side surfaces 201c, 201d, 201e, and 201f connected to each other.

At this time, the lower surface 201b of the light guide plate 200 of the present invention is a groove (not shown) crossing the lower surface 201b of the light guide plate 200 toward the third side surface 201e from the first side surface 201c facing each other. Or a pattern (not shown) is formed, and a groove (not shown) or pattern (not shown) is intersected across the lower surface 201b of the light guide plate 200 from the second side surface 201d to the fourth side surface 201f. ) Is formed to divide and define an inner region of the light guide plate 200.

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

Therefore, the light guide plate 200 is divided into first to fourth regions D1, D2, D3, and D4 through grooves (not shown) or patterns (not shown). In this case, 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) is incident into the light guide plate 200 during backlight division driving. The light can be prevented from overlapping each other.

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

Looking at this in more detail, each of the first to fourth LED assembly (310a, 310b, 310c, 310d) according to the second embodiment of the present invention has a plurality of LEDs 311 in the longitudinal direction of the bar-shaped PCB 313 It is mounted at regular intervals along the way.

Therefore, light is incident on the first region D1 of the light guide plate 200 through the first LED assembly 310a, and the second region D2 of the light guide plate 200 is passed through the second LED assembly 310b. For example, light is incident to the third region D3 of the light guide plate 200 through the third LED assembly 310c and to the fourth region D4 of the light guide plate 200 through the fourth LED assembly 310d. Let's go.

The light incident on the first to fourth regions D1, D2, D3, and D4 of the light guide plate 200 is reflected in each of the regions D1, D2, D3, D4) will proceed inside.

As a result, the liquid crystal display of the present invention can implement backlight division driving that can supply light for each specific region of the liquid crystal panel (110 of FIG. 2) for a more vibrant image representation.

That is, the light guide plate 200 is defined as a plurality of areas D1, D2, D3, and D4 and corresponds to the plurality of areas D1, D2, D3, and D4 of the light guide plate 200, respectively. By positioning 310c and 310d and performing backlight division driving for each of the regions D1, D2, D3, and D4, only the light emitted for each region is supplied to the specific region of the liquid crystal panel (110 in FIG. 2), thereby providing a liquid crystal panel. Contrast ratio can be improved by making a bright image brighter or a dark image darker in the image implemented by 110 of FIG. 2, thereby realizing a vivid image.

In addition, the brightness suitable for the image can be adjusted, so that the image having a dark brightness can have a light of dark brightness, thereby reducing the power consumption of the backlight unit (120 of FIG. 2).

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

In this case, the pattern 205 formed on the lower surface 201b of the light guide plate 200 is formed at a lower density per unit area as the first to fourth LED assemblies 210a, 210b, 210c, and 210d are closer to each other. It is desirable to form at a higher 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 side surfaces of the regions D1, D2, D3, and D4 of the light guide plate 200 may be disposed on the light guide plate. It is preferable that the side surfaces 201c, 201d, 201e, and 201f of the 200 be formed differently. This is to allow light of uniform brightness to enter the light guide plate 200.

That is, as shown in FIG. 5B, the LED assemblies 310b and 310d positioned on the short axis 201d and 201f of the side surfaces of the light guide plate 200 are located on the long axis 201c and 201e of the light guide plate 200. Compared to 310a and 310c, a larger number of LEDs 311 are included.

This is because light emitted from the LED 311 positioned at one side of the light guide plate 200 spreads toward the center of the light guide plate 200, and is disposed on side surfaces 201d and 201f corresponding to a short axis of the light guide plate 200. The distance that light emitted from the correspondingly located LED 311 travels toward the center 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 is longer than the distance traveling toward the center of the light guide plate 200.

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

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

6A and 6B are diagrams for describing backlight division driving according to a second embodiment of the present invention.

As shown, 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. 5B. The first to fourth LED assemblies 310a, 310b, 310c, and 310d respectively correspond to the side surfaces of the regions D1, D2, D3, and D4 of the light guide plate 200.

In this case, the first to fourth LED assemblies 310a, 310b, 310c, and 310d are dividedly driven to allow light to enter the respective areas D1, D2, D3, and D4 of the light guide plate 200.

Accordingly, the present invention can improve the contrast ratio by brightening a bright image or by darkening a dark image by driving backlight division, thereby realizing a vivid image.

That is, as shown in FIG. 6A, in order to make the image implemented in the liquid crystal panel (110 of FIG. 2) corresponding to the first and third regions D1 and D3 of the light guide plate 200 brighter, the first LED assembly may be brighter. Simultaneously lighting 310a and the LEDs 311 of the third LED assembly 310c to inject light into the first and third regions D1 and D3 of the light guide plate 200, and at this time, the second and fourth The LEDs 311 of the LED assemblies 310b and 310d are turned off so that light does not enter the second and fourth regions D2 and D4 of the light guide plate 200.

As a result, an image implemented in the liquid crystal panel (110 of FIG. 2) corresponding to the first and third regions D1 and D3 of the light guide plate 200 is brightly expressed, and the second and fourth areas of the light guide plate 200 are brightly represented. An image implemented in the liquid crystal panel (110 of FIG. 2) corresponding to (D2 and D4) is implemented in the liquid crystal panel (110 of FIG. 2) corresponding to the first and third regions D1 and D3 of the light guide plate 200. The contrast ratio of the image can be improved by being darker than the image.

Alternatively, as shown in FIG. 6B, only the LEDs 311 of the second and fourth LED assemblies 310b and 310d are turned on, so that light is emitted inside the second and fourth regions D2 and D4 of the light guide plate 200. In this case, the image implemented in 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 expressed, and the first and first images of the light guide plate 200 are displayed. An image implemented in the liquid crystal panel (110 in FIG. 2) corresponding to the three regions D1 and D3 may include a liquid crystal panel (110 in FIG. 2) corresponding to the second and fourth regions D2 and D4 of the light guide plate 200. By expressing darker than the image implemented in the, it is possible to improve the contrast ratio of the image.

Through this, a lively image can be realized.

As described above, the liquid crystal display device of the present invention can realize the enlargement without increasing the cost and power consumption even when using the lightweight and thin edge type backlight unit (120 of FIG. 2).

In addition, even when the edge type backlight unit (120 of FIG. 2) is used, light may be supplied to a specific region of the liquid crystal panel (110 of FIG. 2), thereby implementing backlight division driving. Through this, the contrast ratio can be improved, a vivid image can be realized, and brightness can be adjusted according to the image, so that the image having a dark brightness has light of dark brightness, thereby providing a backlight unit. It is possible to reduce the power consumption of 120 (FIG. 2).

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

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

Claims (12)

A liquid crystal panel;
A light guide plate positioned under the liquid crystal panel and divided into a plurality of regions;
A plurality of LED assemblies, each positioned in each of a plurality of divided regions of the light guide plate
And the liquid crystal display device.
The method of claim 1,
And a plurality of divided regions of the light guide plate including edges of the light guide plate, and the plurality of LED assemblies are positioned to surround edges of the light guide plate.
The method of claim 2,
The LED assembly includes a PCB and a plurality of LEDs, and the PCB is bent in a shape to correspond to an edge of the light guide plate.
The method of claim 3, wherein
The first and second side surfaces of the light guide plate may be adjacent to each other, and the PCB may include a first bent portion corresponding to a portion of the first side and a second bent portion corresponding to a portion of the second side. Display.
The method of claim 4, wherein
The first bent part corresponding to the short axis side of the light guide plate has a greater number of LEDs than the second bent part corresponding to the long axis side of the light guide plate.
The method of claim 1,
The plurality of LED assemblies are located on the side of the plurality of divided regions of the light guide plate.
The method according to claim 6,
And a greater number of LEDs than the LED assembly positioned corresponding to the short axis side of the LGP.
The method of claim 1,
And a groove or a pattern formed on the lower surface of the light guide plate between the plurality of regions.
The method of claim 8,
And the groove is formed to cross the lower surface of the light guide plate in a V-cut form from the lower surface toward the upper surface.
The method of claim 1,
The lower surface of the light guide plate is a liquid crystal display device formed with a pattern that becomes denser toward the center.
11. The method of claim 10,
The pattern is one of an elliptical pattern, a polygonal pattern, a hologram pattern, a prism pattern, and a lenticular pattern.
The method of claim 1,
And a reflecting plate positioned below the light guide plate, and an optical sheet positioned above the light guide plate.
KR1020110034091A 2011-04-13 2011-04-13 Liquid crystal display device KR20120116576A (en)

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