KR102009820B1 - Backlight unit and liquid crystal display device including the same - Google Patents

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

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Publication number
KR102009820B1
KR102009820B1 KR1020120103513A KR20120103513A KR102009820B1 KR 102009820 B1 KR102009820 B1 KR 102009820B1 KR 1020120103513 A KR1020120103513 A KR 1020120103513A KR 20120103513 A KR20120103513 A KR 20120103513A KR 102009820 B1 KR102009820 B1 KR 102009820B1
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KR
South Korea
Prior art keywords
led
guide plate
light guide
liquid crystal
circuit board
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KR1020120103513A
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Korean (ko)
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KR20140036861A (en
Inventor
윤혜인
권규오
박준영
Original Assignee
엘지디스플레이 주식회사
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Priority to KR1020120103513A priority Critical patent/KR102009820B1/en
Publication of KR20140036861A publication Critical patent/KR20140036861A/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
    • G02B6/0066—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 characterised by the light source being coupled to the light guide
    • G02B6/0073—Light emitting diode [LED]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S2/00—Systems of lighting devices, not provided for in main groups F21S4/00 - F21S10/00 or F21S19/00, e.g. of modular construction
    • F21S2/005—Systems of lighting devices, not provided for in main groups F21S4/00 - F21S10/00 or F21S19/00, e.g. of modular construction of modular construction
    • 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
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0055—Reflecting element, sheet or layer
    • 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
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
    • H05K2201/10007—Types of components
    • H05K2201/10106—Light emitting diode [LED]

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Engineering & Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • General Engineering & Computer Science (AREA)
  • Planar Illumination Modules (AREA)
  • Liquid Crystal (AREA)

Abstract

The present invention is a light guide plate; An LED assembly positioned on one side of the light guide plate, the LED assembly including a plurality of LEDs mounted on the LED printed circuit board and the LED printed circuit board and having one side of an open side of four sides surrounding the light emitting surface; Provided is a backlight unit including a reflector disposed under the light guide plate.

Description

Backlight unit and liquid crystal display device including the same

The present invention relates to a liquid crystal display, and more particularly, to a backlight unit having a reduced thickness and a thin liquid crystal display including the same.

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, and for this purpose, a backlight unit having a light source is disposed on the back of the liquid crystal panel.

Here, a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (LED), and a light emitting diode (LED) are used as a light source of the backlight unit. .

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

1 is a schematic cross-sectional view of a conventional liquid crystal display.

As shown in FIG. 1, the LCD includes a liquid crystal panel 10, a backlight unit 20, a main frame 30, a bottom frame 50, and a top frame 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 (not shown) interposed therebetween.

First and second polarizing plates 19a and 19b for selectively transmitting only specific light are attached to the outside of each of the first and second substrates 12 and 14, respectively.

The backlight unit 20 is positioned on the rear surface of the liquid crystal panel 10 to supply light to the liquid crystal panel 10.

The backlight unit 20 includes a light emitting diode (LED) assembly 29 arranged along at least one edge length direction of the main frame 30, and a white or silver reflecting plate 25 mounted on the bottom frame 50. ), A light guide plate 23 mounted on the reflecting plate 25, and an optical sheet 21 positioned on the light guide plate 23.

In this case, the LED assembly 29 is located on one side of the light guide plate 23, and includes a plurality of LEDs 29a and an LED printed circuit board (PCB) 29b on which the LEDs 29a are mounted.

The liquid crystal panel 10 and the backlight unit 20 have a top frame 40 surrounding the top edge of the liquid crystal panel 10 with the edges surrounded by a rectangular main frame 30, and a backlight unit 20. Bottom frame 50 covering the back of the) is respectively coupled to the front and rear is integrated through the main frame 30.

With reference to FIG. 2, which is a schematic perspective view of a conventional LED, and FIG. 3, which is a schematic perspective view of a conventional LED assembly, an LED assembly will be described.

As shown in FIG. 2, the LED 29b is a case composed of a body 32 and first to fourth sidewalls 33, 35, 37, 39 protruding from the body 32 to provide a reflective surface. 30, an LED chip 42 located in a space surrounded by the first to fourth sidewalls 33, 35, 37, and 39, and a wire (not shown) to the LED chip 42. And first and second electrode leads 44 and 46 connected to and exposed to the outside of the case 30.

Although not shown, a phosphor covering the LED chip 42 is formed in the space surrounded by the side wall 34.

Referring to FIG. 3, the LED 29b having the above-described configuration is mounted with the first sidewall 33 attached to the LED printed circuit board 29a. Accordingly, the light emitting surface 40 on which the LED chip 42 is positioned is positioned in parallel with the surface of the LED printed circuit board 29a to emit light in a direction parallel to the surface of the LED printed circuit board 29a. . This structure is called a side-view type.

Meanwhile, as liquid crystal displays are widely used in notebooks, smartbooks, and the like, the demand for thickness reduction is increasing. Since the reflector 25, the optical sheet 21, and the like have a very thin configuration among the backlight unit 20, the thickness of the backlight unit 20 is determined by the thickness of the LED assembly 29 and the light guide plate 23. do.

Accordingly, studies to reduce the thickness of the LED (29a), but the situation is facing a limit.

That is, the thickness t1 of the LED 29b is a sum of the thicknesses of the first and second sidewalls 33 and 35 and the light emitting surface 40. There is a limit to the reduction and when the thickness of the light emitting surface 40, the luminous flux is also reduced by reducing the light emitting area.

That is, the thickness should be reduced while maintaining the luminous flux. When the thickness of the LED 29a is reduced, the area of the light emitting surface 40 is also reduced, which causes a limitation in reducing the thickness of the LED 29a to reduce the overall thickness of the backlight unit. Doing.

In the present invention, to reduce the thickness of the backlight unit without reducing the luminous flux.

Accordingly, an object of the present invention is to provide a thin liquid crystal display device.

In order to solve the above problems, the present invention is a light guide plate; An LED assembly positioned on one side of the light guide plate, the LED assembly including a plurality of LEDs mounted on the LED printed circuit board and the LED printed circuit board and having one side of an open side of four sides surrounding the light emitting surface; Provided is a backlight unit including a reflector disposed under the light guide plate.

In the backlight unit of the present invention, an open side of the LED is attached to the LED printed circuit board, and the LED printed circuit board is arranged horizontally with the light guide plate so that the light emitting surface faces the light guide plate. .

In the backlight unit of the present invention, the LED printed circuit board is white color, characterized in that extending between the LED and the light guide plate.

In the backlight unit of the present invention, the LED is attached to the LED printed circuit board so that the light emitting surface is located in parallel with the LED printed circuit board, the LED printed circuit board is arranged perpendicular to the light guide plate and the light emitting surface It is characterized by facing the light guide plate.

In the backlight unit of the present invention, the reflector is characterized in that extending below the LED.

In the backlight unit of the present invention, it comprises an optical sheet positioned on the light guide plate.

In another aspect, the present invention is a liquid crystal panel; Located in the lower portion of the liquid crystal panel, a light guide plate, and located on one side of the light guide plate, mounted on the LED printed circuit board and the LED printed circuit board, one of the four sides surrounding the light emitting surface has an open shape Provided is a liquid crystal display including a LED assembly including an LED and a backlight unit including a reflector disposed under the light guide plate.

In the liquid crystal display device of the present invention, an open side of the LED is attached to the LED printed circuit board, the LED printed circuit board is arranged horizontally with the light guide plate, the light emitting surface is directed toward the light guide plate. do.

In the liquid crystal display of the present invention, the LED printed circuit board is white in color and extends between the LED and the light guide plate.

In the liquid crystal display device of the present invention, the LED is attached to the LED printed circuit board so that the light emitting surface is positioned in parallel with the LED printed circuit board, the LED printed circuit board is arranged perpendicular to the light guide plate to the light emitting A surface is directed toward the light guide plate.

In the liquid crystal display of the present invention, the reflector is characterized in that extending below the LED.

 In the liquid crystal display of the present invention, the backlight unit includes an optical sheet positioned between the liquid crystal panel and the light guide plate.

A liquid crystal display device of the present invention, comprising: a bottom frame covering a rear surface of the backlight unit; A main frame surrounding side surfaces of the backlight unit and the liquid crystal panel; And a top frame covering the front edge of the liquid crystal panel and coupled to the bottom frame and the main frame.

In the backlight unit according to the present invention, one side of the LED case is opened, and by using the side-view type LED to which one side of the open side is attached to the LED printed circuit board, the thickness of the backlight unit can be reduced and the white LED printed circuit board The fall of the luminous flux is prevented because of the reflection by.

In addition, by using a top-view type LED in which one side of the LED case is open and the open side is positioned to face the reflecting plate, the thickness of the backlight unit can be reduced, and the luminous flux is prevented due to reflection by the reflecting plate.

In addition, by including the above-described backlight unit has the effect of providing a thin liquid crystal display device.

1 is a schematic cross-sectional view of a conventional liquid crystal display.
2 is a schematic perspective view of a conventional LED.
3 is a schematic perspective view of a conventional LED assembly.
4 is a schematic exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.
5 is a schematic cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.
6A and 6B are schematic cross-sectional and perspective views of LEDs according to embodiments of the present invention.
7 is a schematic perspective view of an LED assembly according to an embodiment of the present invention.
8 is a schematic cross-sectional view of a liquid crystal display according to another exemplary embodiment of the present invention.
FIG. 9 is a schematic perspective view of an LED assembly used in the liquid crystal display shown in FIG. 8.

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

4 is a schematic exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 5 is a schematic cross-sectional view of the liquid crystal display according to an exemplary embodiment of the present invention.

As illustrated, the liquid crystal display includes a liquid crystal panel 110, a backlight unit 120, a main frame 130, a top frame 140, and a bottom frame 150.

The liquid crystal panel 110 plays a key role in image expression and includes first and second substrates 112 and 114 bonded to each other with a liquid crystal layer interposed therebetween.

Although not shown, a plurality of gate lines and data lines intersect each other to define a pixel on an inner surface of the first substrate 112, commonly referred to as a lower substrate or an array substrate, and a thin film transistor is formed at each crossing point. TFTs are provided and connected one-to-one with the transparent pixel electrodes formed in each pixel.

In addition, a color filter of red (R), green (G), and blue (B) color corresponding to each pixel may be formed on an inner surface of the second substrate 114 called an upper substrate or a color filter substrate. A black matrix is provided to cover non-display elements such as gate lines, data lines, and thin film transistors. In addition, a transparent common electrode covering them is provided.

When a signal is applied to the gate line and the thin film transistor is turned on, a signal is applied to the pixel electrode through the data line. Accordingly, an electric field is formed between the pixel electrode and the common electrode, and the liquid crystal molecules of the liquid crystal layer are driven by the electric field.

Along the at least one edge of the liquid crystal panel 110, the gate and the data printed circuit board 117 are connected to each other via a connection member 116 such as a flexible circuit board, and closely adhered to the main frame 130 in the modularization process.

In addition, an alignment layer (not shown) determining an initial molecular alignment direction of the liquid crystal is interposed between the first and second substrates 112 and 1214 and the liquid crystal layer of the liquid crystal panel 110, and filled therebetween. Seal patterns (not shown) are formed along edges of the first and second substrates 112 and 114 to prevent leakage of the liquid crystal layer. First and second polarizing plates 119a and 119b are attached to outer surfaces of the first and second substrates 112 and 114, respectively.

The backlight unit 120 is positioned below the liquid crystal panel 110 to supply light. As described above, the difference in transmittance generated by driving the liquid crystal molecules of the liquid crystal layer is expressed to the outside. The image will be implemented.

The backlight unit 120 includes a light guide plate 123, a reflective plate 125, an optical sheet 121, and an LED assembly 129.

The light guide plate 123 is disposed under the liquid crystal panel 110, and the reflector plate 125 is positioned on the rear surface of the light guide plate 123. In addition, the optical sheet 121 is positioned above the light guide plate 123, that is, between the liquid crystal panel 110 and the light guide plate 123.

The LED assembly 129 is located at one side of the light guide plate 123 to supply light toward the light guide plate 123. That is, the light emitted from the LED assembly 129 is incident on the light guide plate 123 and then spread evenly inside the light guide plate 123 by total reflection and becomes a uniform surface light source through the optical sheet 121 to form the liquid crystal. Provided on panel 110.

The light guide plate 123 may include a pattern (not shown) of a specific shape on the rear surface to supply a uniform surface light source. For example, the pattern may be an elliptical shape, a polygon shape, or a hologram pattern.

The reflector 125 reflects light from the rear surface of the light guide plate 123 to increase light efficiency. The optical sheet 121 may include at least one diffusion sheet and at least one light collecting sheet.

The LED assembly 129 is a side-view type, mounted on the LED printed circuit board 129a and the LED printed circuit board 129a positioned in parallel with the light guide plate 123 and emitting light through a side surface. It includes a plurality of LEDs (129b). The LED assembly 129 will be described later in detail.

The main frame 130 surrounds side surfaces of the liquid crystal panel 110 and the backlight unit 120, and the bottom frame 150 covers the rear surface of the backlight unit 120. In addition, the top frame 140 covers the front edge of the liquid crystal panel 110 and is combined with the main frame 130 and the bottom frame 140 to form a liquid crystal display device.

6A and 6B are each a schematic cross-sectional view and perspective view of an LED according to an embodiment of the present invention, and FIG. 7 is a schematic perspective view of an LED assembly according to an embodiment of the present invention.

6A and 6B, the LED 129a includes a case 152 including a body 154 and sidewalls 156 protruding from an upper surface of the body 154 to serve as a reflective surface. The LED chip 160 positioned on the upper surface of the body 154 to be surrounded by the sidewall 156 and the LED chip 160 through first and second wires 166 and 168, respectively. The case 152 includes first and second electrode leads 162 and 166 exposed to the outside.

In addition, although not shown, a phosphor 170 covering the LED chip 160 is formed in a space surrounded by the sidewall 156.

In this case, the sidewall 156 is composed of first and second sidewalls 156a and 156b facing each other and a third sidewall 156c connecting one end of each of the first and second sidewalls 156a and 156b. . That is, the case 152 has an open surface, and the LED chip 160 and the phosphor 170 are exposed through the open side surface. In other words, one side of the light emitting surface 172 that emits light has an open structure.

The LED 129b is mounted on the case 152 to connect the LED chip 160 to the first and second electrode leads 162 and 164, and injected and cured by the phosphor 170. 152 may be formed by cutting one surface.

Referring to FIG. 7, which is a schematic perspective view of an LED assembly according to an exemplary embodiment of the present invention, the LED 129b includes a light emitting surface 172 through which light is emitted from the LED chip 160, and the LED printed circuit board 129a. It is mounted so as to be parallel to the surface and the open side of the case 152 is in contact with the surface of the LED printed circuit board 129a.

The LED 129b has an open side attached to the LED printed circuit board 129a with one side of the case 152 open, and the light emitting surface 172 faces the light guide plate 123. The printed circuit board 129a is disposed horizontally with the light guide plate 123. Accordingly, the thickness t2 of the LED 129b is the sum of the thicknesses of the light emitting surface 172 and the third sidewall 156c. Thus, the thickness is reduced by one sidewall compared to the conventional LED (29b of FIG. 3).

On the other hand, since the LED 129b has a structure in which one side of the case 152 is opened, that is, a structure in which the reflective surface does not exist on one side, there is a possibility that the luminous flux is reduced.

However, in the present invention, the LED printed circuit board 129a has a white color with high reflectance, and one end of the LED printed circuit board 129a extends to overlap one end of the light guide plate 123 so that Compensation for luminous flux degradation due to omission of the reflection surface is compensated.

Compared to the side wall of the mold material, the reflectance of the white LED printed circuit board 129a is higher, and simulation results show that one side is open compared to a structure including a conventional LED having a thickness of 0.5 mm and has a thickness of 0.44 mm. It was confirmed that the luminous flux was increased in the structure including the LED. (5.974lm-> 6.109lm, about 2.3% increase)

Meanwhile, without reflecting the LED printed circuit board 129a between the light guide plate 123 and the LED 129b, the reflector plate 125 extends between the light guide plate 123 and the LED 129b so that the LED 129b may be formed. One side of the case 152 may be opened to prevent light loss that may occur. That is, light loss can be prevented by extending the reflector 125 below the LED 129b.

As described above, in the backlight unit and the liquid crystal display including the side-view type LED, one side of the case 152 of the LED 129b is opened and the open side is in contact with the LED printed circuit board 129a. By placing the LED assembly 129 mounted on one side of the light guide plate 123, the thickness is reduced by one side wall of the case 152.

Accordingly, the present invention provides a backlight unit having a reduced thickness and a thin liquid crystal display including the same.

In addition, one side of the case 152 of the LED 129b is opened so that the reflective surface is omitted, but the LED printed circuit board 129a is positioned to have a high reflectance white color and extends between the light guide plate 123 and the LED 129b. Or by positioning the reflector 125 to extend between the light guide plate 123 and the LED 129b, it is possible to prevent the luminous flux from being reduced.

FIG. 8 is a schematic cross-sectional view of a liquid crystal display according to another embodiment of the present invention, and FIG. 9 is a schematic perspective view of an LED assembly used in the liquid crystal display shown in FIG.

As illustrated, the liquid crystal display device includes a backlight unit 220, a bottom frame 250 covering the rear surface of the backlight unit 220, a liquid crystal panel (not shown) positioned on the backlight unit 220, and The main frame 230 surrounding the backlight unit 220 and the side surface of the liquid crystal panel, and a top frame covering the front edge of the liquid crystal panel and combined with the main frame 230 and the bottom frame 250 (not shown) ).

The backlight unit 220 includes a light guide plate 223, a reflector 225, an optical sheet 221, and an LED assembly 229.

The light guide plate 223 is disposed under the liquid crystal panel (not shown), and the reflector plate 225 is located on the rear surface of the light guide plate 223. In addition, the optical sheet 221 is positioned above the light guide plate 223, that is, between the liquid crystal panel (not shown) and the light guide plate 223.

The LED assembly 229 is positioned at one side of the light guide plate 223 to supply light toward the light guide plate 223. That is, the light emitted from the LED assembly 229 is incident on the light guide plate 223 and then spread evenly inside the light guide plate 223 by total reflection and becomes a uniform surface light source through the optical sheet 221. Provided on panel 210.

The LED assembly 229 is of a top-view type, mounted on the LED printed circuit board 229a and the LED printed circuit board 229a positioned perpendicular to the light guide plate 223 and lighted through the front surface. And a plurality of LEDs 229b to emit light.

The LED 229a includes a case 252 composed of a body 254 and a sidewall 256 protruding from an upper surface of the body 254 to serve as a reflective surface, and to be surrounded by the sidewall 256. LED chips (not shown) positioned on the upper surface of the body 254, and first and second wires (not shown) respectively connected to the LED chips (not shown) and exposed to the outside of the case 152. And first and second electrode leads (not shown). In addition, a phosphor (not shown) covering the LED chip (not shown) is formed in a space surrounded by the side wall 256.

In this case, the side wall 256 is composed of first and second side walls (256a, 256b) facing each other and a third side wall (256c) connecting one end of each of the first and second side walls (256a, 256b) . That is, the case 252 has a shape in which one surface is open and the LED chip (not shown) and the phosphor (not shown) are exposed through the open side. In other words, one side of the light emitting surface 272 that emits light has an open structure.

The LED 229b is mounted such that a light emitting surface 272 emitting light from an LED chip (not shown) contacts the surface of the LED printed circuit board 129a perpendicularly to the surface of the LED printed circuit board 229a. The LED assembly 229 is placed on the side of the light guide plate 223 such that the open side of the LED 229b faces the bottom frame 250.

The LED 229b is attached to the LED printed circuit board 229a with one side of the case 252 open, and the side of the light guide plate 223 with the open side facing downward. As a result, the thickness t2 of the LED 229b is the sum of the thicknesses of the light emitting surface 272 and the third sidewall 256c. Thus, the thickness is reduced by one sidewall compared to the conventional LED (29b of FIG. 3).

At this time, in order to increase the light efficiency, the reflective plate 225 positioned on the rear surface of the light guide plate 223 extends to the lower portion of the LED 229b. That is, the open side of the LED 229b faces the reflecting plate 225.

Accordingly, one side of the case 252 of the LED 229b is opened so that a reflective surface does not exist on one side of the light emitting surface 272, but is emitted to the open side of the case 252 by the reflecting plate 225. Since the reflected light is reflected, there is no problem of deterioration of light efficiency.

As described above, in a backlight unit and a liquid crystal display including a side-view type LED, one side of the case 252 of the LED 229b is opened and the bottom of the LED 229b, that is, the body 254 is an LED. By being positioned on one side of the light guide plate 223 so that the open side faces downward in the state of being attached to the printed circuit board 229a, the thickness of the case 252 is reduced by one side wall.

Accordingly, the present invention provides a backlight unit having a reduced thickness and a thin liquid crystal display including the same.

In addition, although one side of the case 252 of the LED 229b is opened and the reflection surface is omitted, the reflection plate 225 is formed to extend to the lower portion of the LED 229b, thereby preventing the reduction of the luminous flux.

That is, the backlight unit of the present invention and the liquid crystal display including the same have the advantage that the thickness is reduced without the luminous flux.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art various modifications and changes to the present invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

110, 210: liquid crystal panel 120, 220: backlight unit
123, 223: Light guide plate 125, 225: Reflector plate
121, 221: Optical sheet 129, 229: LED assembly
129a, 229a: LED printed circuit board 129b, 229b: LED
152, 252: Cases 154, 254: Body
156, 256: side walls 172, 272: emitting surface
130, 230: main frame 140, 240: top frame
150, 250: bottom frame

Claims (14)

delete delete delete A light guide plate;
An LED assembly positioned on one side of the light guide plate, the LED assembly including a plurality of LEDs mounted on the LED printed circuit board and the LED printed circuit board and having one side of an open side of four sides surrounding the light emitting surface;
A reflection plate positioned below the light guide plate,
And the LED is attached to the LED printed circuit board such that the light emitting surface is positioned in parallel with the LED printed circuit board, the light emitting surface facing the light guide plate, and the open one side faces downward.
The method of claim 4, wherein
The reflector is a backlight unit, characterized in that extending below the LED.
The method of claim 4, wherein
And a optical sheet positioned on the light guide plate.

delete delete delete A liquid crystal panel;
Located in the lower portion of the liquid crystal panel, a light guide plate, and located on one side of the light guide plate, mounted on the LED printed circuit board and the LED printed circuit board, one of the four sides surrounding the light emitting surface has an open shape And a backlight unit including an LED assembly including an LED and a reflector disposed below the light guide plate.
The LED is attached to the LED printed circuit board so that the light emitting surface is positioned in parallel with the LED printed circuit board, the light emitting surface facing the light guide plate and the open one side is directed to the lower side. .
The method of claim 10,
And the reflector extends below the LED.
The method of claim 10,
And the backlight unit includes an optical sheet disposed between the liquid crystal panel and the light guide plate.
The method of claim 10,
A bottom frame covering a rear surface of the backlight unit;
A main frame surrounding side surfaces of the backlight unit and the liquid crystal panel;
And a top frame covering a front edge of the liquid crystal panel and coupled to the bottom frame and the main frame.
The method of claim 10,
A bottom frame covering a rear surface of the backlight unit;
And the open one side is disposed toward the bottom frame.
KR1020120103513A 2012-09-18 2012-09-18 Backlight unit and liquid crystal display device including the same KR102009820B1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005167136A (en) * 2003-12-05 2005-06-23 Masami Nei Semiconductor light emitting device and method for manufacturing same
JP2010134413A (en) * 2008-10-31 2010-06-17 Stanley Electric Co Ltd Reflective sheet with light-guiding and light-emitting function and liquid crystal backlight using the sheet

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20070059268A (en) * 2005-12-06 2007-06-12 삼성전자주식회사 Liquid crystal display device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005167136A (en) * 2003-12-05 2005-06-23 Masami Nei Semiconductor light emitting device and method for manufacturing same
JP2010134413A (en) * 2008-10-31 2010-06-17 Stanley Electric Co Ltd Reflective sheet with light-guiding and light-emitting function and liquid crystal backlight using the sheet

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