KR20110055155A - Backlight unit and liquid crystal display device having the same - Google Patents

Backlight unit and liquid crystal display device having the same Download PDF

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Publication number
KR20110055155A
KR20110055155A KR1020090112062A KR20090112062A KR20110055155A KR 20110055155 A KR20110055155 A KR 20110055155A KR 1020090112062 A KR1020090112062 A KR 1020090112062A KR 20090112062 A KR20090112062 A KR 20090112062A KR 20110055155 A KR20110055155 A KR 20110055155A
Authority
KR
South Korea
Prior art keywords
light
guide plate
light guide
liquid crystal
crystal display
Prior art date
Application number
KR1020090112062A
Other languages
Korean (ko)
Inventor
조기현
Original Assignee
엘지디스플레이 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 엘지디스플레이 주식회사 filed Critical 엘지디스플레이 주식회사
Priority to KR1020090112062A priority Critical patent/KR20110055155A/en
Publication of KR20110055155A publication Critical patent/KR20110055155A/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
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0036—2-D arrangement of prisms, protrusions, indentations or roughened surfaces
    • 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

Abstract

PURPOSE: A backlight unit and liquid crystal display device including the same are provided to prevent the light leakage phenomenon and to increase display quality. CONSTITUTION: A light source(150) emits light. A light guide plate(140) is arranged with the light source. A light compensating pattern is formed in one side of the light guide plate. The light is incident into the other side of the light guide plate from the inside of the light guide plate along a slope angle between a first slope plate and a second slope plate.

Description

BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY DEVICE HAVING THE SAME}

The present invention relates to a backlight unit, and more particularly, to a backlight unit capable of improving edge light leakage and a liquid crystal display having the same.

Liquid crystal display is a flat panel display that displays images using liquid crystal. It is thin, light, and has low power consumption compared to other display devices. It is used.

Such a liquid crystal display device includes a liquid crystal display panel for displaying an image and a backlight unit for supplying light to the liquid crystal display panel.

As the light source of the backlight unit, EL (Electro Luminescence), CCFL (Cold Cathode Fluorescent Lamp), HCFL (Hot Cathode Fluorescent Lamp), and a light emitting diode (LED) are used.

In the CCFL type backlight assembly, mercury encapsulated inside a fluorescent lamp forms an amalgam easily by combining with a metal, thereby degrading the life of the lamp, causing a great change in luminance due to temperature changes, and using heavy mercury, a highly toxic heavy metal. The disposal of the waste is a problem.

In order to solve the above problems, a backlight unit using a light emitting diode (LED) is proposed.

The light emitting diode is a point light source and may be formed of a plurality of red, green, and blue, or white. The light emitting diode may implement a high brightness backlight unit by minimizing the size of the backlight unit and maintaining uniformity of light.

The liquid crystal display is classified into an edge type and a direct type according to the shape of the light source. The edge type backlight unit includes a light guide plate at a side surface and a light guide plate provided at a rear surface of the liquid crystal display panel to guide light emitted from the side surface to the front. The direct type backlight unit is applied to a large liquid crystal display device of 12 inches or more, and includes a plurality of light sources on the back of the liquid crystal panel, and the light emitted from the plurality of light sources is irradiated to the front liquid crystal display panel.

In a typical edge type liquid crystal display device, light emitted from a light emitting diode is incident on an incident surface of the light guide plate and is converted into a surface light source.

However, in a general edge type liquid crystal display, when light emitted from the light emitting diode is incident through the incident surface of the light guide plate and is converted into a surface light source, light is concentrated on the side facing the incident surface of the light guide plate adjacent to the light emitting diode. There was a problem that light leakage occurs. That is, in general, an edge type liquid crystal display device has a light incident on one side (incidence surface) of the light guide plate and is concentrated on the other side (entrance surface) facing the one side (incident surface) due to the straightness. There was a problem that a light leakage phenomenon that light leaks from the other side of the light guide plate occurs.

An object of the present invention is to provide a backlight unit capable of improving edge light leakage and a liquid crystal display device having the same.

The backlight unit according to an embodiment of the present invention,

A light source for emitting light; And a light guide plate disposed in parallel with the light source, wherein the light guide plate is formed with a light correction pattern having peaks and valleys on the other side facing one side adjacent to the light source.

In addition, the liquid crystal display device of the present invention,

A light source for emitting light; A light guide plate disposed in parallel with the light source; And a liquid crystal display panel disposed on the light guide plate, wherein the light guide plate is formed with a light correction pattern having peaks and valleys on the other side facing one side adjacent to the light source.

In the liquid crystal display of the present invention, a light correction pattern is formed on the light incident plate of the light guide plate, thereby diffusing light incident on the light guide plate and exiting through the light incident plate of the light guide plate, thereby improving light leakage phenomenon generated at the light incident plate of the light guide plate.

Therefore, the present invention has the advantage of improving the display quality by improving the light leakage phenomenon occurring at the edge facing the area where the light source is disposed when the image is displayed.

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

1 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention, FIG. 2 is a perspective view illustrating region A of FIG. 1, and FIG. 3 is a plan view illustrating a plurality of light sources and a light guide plate of FIG. 1. to be.

1 to 3, the liquid crystal display according to the exemplary embodiment of the present invention is provided with a liquid crystal display panel 110 on which an image is displayed, and is disposed under the liquid crystal display panel 110 to provide light. The backlight unit 120 may include a support main 118 that supports an edge of a lower surface of the liquid crystal display panel 110 and is coupled to the backlight unit 120.

The liquid crystal display of the present invention further includes a top case 100 surrounding the edge of the top surface of the liquid crystal display panel 110 and coupled to the backlight unit 120.

Although not shown in detail, the liquid crystal display panel 110 is bonded to a thin film transistor (TFT) substrate and a color filter substrate to maintain a uniform cell gap facing each other, and a liquid crystal layer interposed between the two substrates. It includes. In the thin film transistor substrate, a plurality of gate lines are formed, a plurality of data lines intersecting the plurality of gate lines are formed, and a thin film transistor TFT is formed at an intersection area of the gate line and the data line.

A gate driving printed circuit board (113) for supplying a scan signal to a gate line is provided at an edge of the liquid crystal display panel 110, and a data driving printed circuit board (PCB) for supplying a data signal to a data line. 115 is provided.

The gate and data driving PCBs 113 and 115 are electrically connected to the liquid crystal display panel 110 by a chip on film 117. Here, the COF 117 may be changed to a tape carrier package (TCP).

The backlight unit 120 is disposed in parallel with the bottom cover 170 having an upper surface, a plurality of light sources 150 provided on an inner side surface of the bottom cover 170, and the plurality of light sources 150. And a light guide plate 140 for converting light incident from the light source 150 into surface light, optical sheets 130 disposed on the light guide plate 140 to collect and diffuse light, and a lower portion of the light guide plate 140. The reflective sheet 160 is disposed on the light guide plate 140 to reflect the light traveling toward the lower surface of the liquid crystal display panel 110 to reduce light loss.

The plurality of light sources 150 may include light emitting diodes (LEDs) disposed at regular intervals.

One side of the light guide plate 140 adjacent to the plurality of light sources 150 is defined as the incident surface, and the other side of the light guide plate 140 facing the incident surface is defined as the incident surface.

A light correction pattern 141 having peaks and valleys is formed on the incident surface of the light guide plate 140.

The light correction pattern 141 has a function of improving a light leakage phenomenon in which light leaks in the upper direction of the light incident surface by changing a path of light emitted from the inside of the light guide plate 140 to the light incident surface.

The light correction pattern 141 has peaks and valleys in the outward direction and has first and second inclined surfaces 143 and 145 which face each other and are symmetrical to each other.

The first and second inclined surfaces 143 and 145 have inclined angles that are symmetrical with respect to the other side of the light guide plate 140.

The light correction pattern 141 refracts the light exiting to the incident surface of the light guide plate 140 by using the first and second inclined surfaces 143 and 145 to diffuse the light.

That is, the light correction pattern 141 distributes the light emitted to the light incident plate of the light guide plate 140 in the left / right directions by using the first and second inclined surfaces 143 and 145.

The light compensation pattern 141 according to the exemplary embodiment of the present invention is designed such that an angle formed between the first inclined surface 143 and the second inclined surface 145 has 90 degrees.

In addition, the height of the light correction pattern 141 protruding to the outside of the light guide plate 140 is 0.05 mm to 0.2 mm.

In this case, the pitch of each of the light compensation patterns 141 may be changed by designing an angle formed by the first and second inclined surfaces 143 and 145 to 90 degrees and the protruding height of 0.05 mm to 0.2 mm. have.

Although not shown in detail in the drawing, a diffusion material or a diffusion pattern capable of diffusing light incident from the light source 150 may be formed on an entrance surface defined as one side of the light guide plate 140, and the light guide plate 140 may be formed. A separate diffusion member may be provided.

Although the liquid crystal display according to the exemplary embodiment of the present invention has been described in detail with respect to the shape of the light correction pattern 141 having peaks and valleys, the present invention is not limited thereto. The light correction pattern can be applied.

In the liquid crystal display according to the exemplary embodiment described above, the light correction pattern 141 is formed on the incident surface of the light guide plate 140 and is incident on the light guide plate 140 to be emitted through the incident surface of the light guide plate 140. Diffusion of light may improve light leakage occurring on the incident surface of the light guide plate 140.

Therefore, the present invention has the advantage of improving the display quality by improving the light leakage phenomenon occurring at the edge facing the area where the light source 150 is disposed when the image is displayed.

4 is a plan view illustrating a light source and a light guide plate of a liquid crystal display according to another exemplary embodiment of the present invention.

As shown in FIG. 4, the liquid crystal display according to another exemplary embodiment of the present invention includes a plurality of light sources 150 disposed at regular intervals and a light guide plate 240 disposed in parallel with the light sources 150. do.

The plurality of light sources 150 are provided with light emitting diodes (LEDs) as point light sources.

One side of the light guide plate 240 adjacent to the plurality of light sources 150 is defined as the incident surface, and the other side of the light guide plate 240 facing the incident surface is defined as the incident surface.

A light correction pattern 241 having peaks and valleys is formed on the incident surface of the light guide plate 240.

The light correction pattern 241 has a function of improving a light leakage phenomenon in which light leaks in the upper direction of the light incident surface by changing a path of light emitted from the light guide plate 240 to the light incident surface.

The light correction pattern 241 has peaks and valleys in the outward direction, and has first and second inclined surfaces 243 and 245 which face each other and are symmetric.

The first and second inclined surfaces 243 and 245 may be inclined to be symmetrical with respect to the other side of the light guide plate 240.

The light compensation pattern 241 refracts the light exiting to the incident surface of the light guide plate 240 using the first and second inclined surfaces 243 and 245 to diffuse the light.

That is, the light correction pattern 241 disperses the light exiting to the incident surface of the light guide plate 240 using the first and second inclined surfaces 243 and 245 in the left and right directions.

The light correction pattern 241 according to the exemplary embodiment of the present invention is designed such that angles θ1 and θ2 formed by the first inclined surface 243 and the second inclined surface 245 exceed 90 degrees.

In addition, the height of the light correction pattern 241 protruding to the outside of the light guide plate 240 is 0.05 mm to 0.2 mm.

The pitch of each of the light compensation patterns 241 is designed such that angles θ1 and θ2 formed by the first and second inclined surfaces 243 and 245 are greater than 90 degrees, and the protruding height is 0.05 mm to 0.2. By designing in mm, it can be changed.

Although the liquid crystal display according to another exemplary embodiment of the present invention has been described with reference to the shape of the light correction pattern 241 having peaks and valleys, the present invention is not limited thereto. The light correction pattern may be applied.

In addition, the liquid crystal display according to another exemplary embodiment of the present invention has been described with the limitation that the angle formed by the first and second inclined surfaces 243 and 245 is greater than 90 degrees, but is not limited thereto. And the angle formed by the second inclined surface may be less than 90 degrees.

In the liquid crystal display according to the exemplary embodiment described above, the light correction pattern 241 is formed on the incident surface of the light guide plate 240 and is incident on the light guide plate 240 to be emitted through the incident surface of the light guide plate 240. Diffusion of light may improve light leakage occurring on the incident surface of the light guide plate 240.

Therefore, the present invention has the advantage of improving the display quality by improving the light leakage phenomenon occurring at the edge facing the area where the light source 150 is disposed when the image is displayed.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

1 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 2 is a perspective view illustrating region A of FIG. 1.

3 is a plan view illustrating a plurality of light sources and a light guide plate of FIG. 1.

4 is a plan view illustrating a light source and a light guide plate of a liquid crystal display according to another exemplary embodiment of the present invention.

Claims (16)

A light source for emitting light; And And a light guide plate disposed to be parallel to the light source. And a light correction pattern having peaks and valleys on the other side of the light guide plate facing one side adjacent to the light source. According to claim 1, The light compensation pattern is formed in the form of having a peak and valley from the other side surface of the light guide plate to the outside, and has a first and second inclined surface symmetrical to each other. The method of claim 2, And the light compensation pattern refracts light emitted from the inside of the light guide plate to the other side of the light guide plate in left / right directions according to the inclination angles of the first and second inclined surfaces. The method of claim 2, The angle formed by the first and second inclined surfaces is designed to be 90 degrees. The method of claim 2, The angle formed by the first and second inclined surfaces is designed to exceed 90 degrees or less than 90 degrees. According to claim 1, The light compensation pattern is a backlight unit, characterized in that the height of the mountain projecting outward from the other side surface of the light guide plate is 0.05mm to 0.2mm. The method of claim 2, The pitch of each of the light compensation pattern is changed according to the angle formed by the first and the second inclined plane and the height of the protruding peaks. According to claim 1, The mountain end of the light correction pattern has a round shape. A light source for emitting light; A light guide plate disposed in parallel with the light source; And A liquid crystal display panel disposed on the light guide plate; And a light correction pattern having peaks and valleys on the other side of the light guide plate facing one side adjacent to the light source. The method of claim 9, The light correction pattern is formed in a form having a peak and a valley from the other side surface of the light guide plate to the outside, and has a first and second inclined surfaces symmetrical to each other. The method of claim 10, And the light correction pattern refracts light emitted from the inside of the light guide plate to the other side of the light guide plate in left / right directions according to the inclination angles of the first and second inclined surfaces. The method of claim 10, The angle formed by the first and second inclined surfaces is designed to be 90 degrees. The method of claim 10, And the angle formed by the first and second slopes is greater than 90 degrees or less than 90 degrees. The method of claim 9, The light correction pattern is a liquid crystal display, characterized in that the height of the acid projecting outward from the other side surface of the light guide plate is 0.05mm to 0.2mm. The method of claim 10, And a pitch of each of the light correction patterns is changed according to an angle formed by the first and second slopes and a height of the protruding peaks. The method of claim 9, And an acid tip of the light correction pattern has a round shape.
KR1020090112062A 2009-11-19 2009-11-19 Backlight unit and liquid crystal display device having the same KR20110055155A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20160138624A (en) * 2015-05-26 2016-12-06 주식회사 엘엠에스 Light guide plate and backlight unit including the same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20160138624A (en) * 2015-05-26 2016-12-06 주식회사 엘엠에스 Light guide plate and backlight unit including the same

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