KR20090053631A - Backlight unit and liquid crystal display having thesame, and method thereof - Google Patents

Backlight unit and liquid crystal display having thesame, and method thereof Download PDF

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Publication number
KR20090053631A
KR20090053631A KR1020070120535A KR20070120535A KR20090053631A KR 20090053631 A KR20090053631 A KR 20090053631A KR 1020070120535 A KR1020070120535 A KR 1020070120535A KR 20070120535 A KR20070120535 A KR 20070120535A KR 20090053631 A KR20090053631 A KR 20090053631A
Authority
KR
South Korea
Prior art keywords
reflective sheet
light emitting
liquid crystal
crystal display
printed circuit
Prior art date
Application number
KR1020070120535A
Other languages
Korean (ko)
Inventor
문원택
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 KR1020070120535A priority Critical patent/KR20090053631A/en
Publication of KR20090053631A publication Critical patent/KR20090053631A/en

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Classifications

    • 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
    • G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
    • G02B6/0031—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
    • G02F1/133602—Direct backlight
    • G02F1/133603—Direct backlight with LEDs
    • 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
    • G02F1/133602—Direct backlight
    • G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • 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
    • G02F1/133602—Direct backlight
    • G02F1/133611—Direct backlight including means for improving the brightness uniformity

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

Abstract

The present invention discloses a backlight unit having the advantages of uniform brightness and thinning. The disclosed backlight unit includes a plurality of printed circuit boards arranged at regular intervals, a plurality of light emitting diodes mounted at regular intervals on the printed circuit board, and a reflective sheet disposed on the printed circuit board, The reflective sheet may include a plurality of diffusion lenses for diffusing light in a region corresponding to the plurality of light emitting diodes.

Diffusion, Lens, LED, Thin, Luminance

Description

BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY HAVING THESAME, AND METHOD THEREOF

The present invention relates to a backlight unit, and more particularly, to a backlight unit having advantages of uniform brightness and thinning, a liquid crystal display device having the same, and a manufacturing method thereof.

Cathode ray tube (CRT), one of the widely used display devices, is mainly used for monitors such as TVs, measuring devices, and information terminal devices, but the size and weight of electronic products are reduced due to the weight and size of the CRT itself. Could not actively respond to the response.

As a solution to this problem, the liquid crystal display device has a tendency that its application range is gradually widening due to the features such as light weight, thinning, low power consumption driving. Accordingly, in order to meet the needs of users, liquid crystal display devices are progressing in the direction of large area, thinning, and low power consumption.

BACKGROUND ART A liquid crystal display device is a display device that displays an image by controlling an amount of light passing through a liquid crystal, and is widely used for advantages such as thinning and low power consumption.

Unlike the CRT, the liquid crystal display is not a display device that emits light by itself, and thus, a backlight unit including a separate light source is provided on the back of the liquid crystal display panel to provide light for visually representing an image.

The backlight unit has two types, a direct method and an edge method, depending on the position of the light source.

In the edge method, a light source is disposed on a side of a flat plate, and the light emitted from the light source is irradiated onto the entire surface of the liquid crystal display panel using a light guide plate. On the other hand, in the direct method, a plurality of light sources are disposed on the back of the liquid crystal display panel to directly irradiate light directly under the liquid crystal display panel, so that the luminance can be increased by a plurality of light sources compared to the edge method, and the light emitting surface is wider. There is an advantage to this.

Recently, as the size of the liquid crystal display device increases, the size of the backlight unit also increases. As a result, the liquid crystal display device employs a backlight unit of a direct type.

The backlight unit uses a plasma light source such as a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent tube (HCFL), an external electrode fluorescent tube (EEFL), and an external & internal electrode fluorescent tube (EIFL). Or a light emitting diode (LED) is used.

Among them, light emitting diodes (LEDs) that emit light have been used for their long life, low power, small size, and high durability.

However, in the general direct-type backlight unit, since a plurality of light emitting diodes (LEDs) are disposed directly under the liquid crystal display panel and irradiates light directly toward the liquid crystal display panel, the backlight unit is not disposed with the area where the light emitting diodes (LEDs) are arranged. There is a problem that it is difficult to implement uniform luminance due to the difference in luminance between the regions. The difference in luminance means that light and dark portions occur in regions where white light emitting diodes are arranged and regions where white light emitting diodes are disposed.

In order to realize uniform luminance, there is a method of maintaining a sufficient distance between the light emitting diode (LED) and the liquid crystal display panel or installing a diffusion plate for diffusion, but there is a problem in that the thickness of the liquid crystal display device is difficult.

An object of the present invention is to provide a backlight unit that can implement a uniform brightness.

Another object of the present invention is to provide a backlight unit, which is advantageous for thinning, a liquid crystal display device having the same, and a method of manufacturing the same.

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

A plurality of printed circuit boards arranged at regular intervals; A plurality of light emitting diodes mounted on the printed circuit board at regular intervals; And a reflective sheet disposed on the printed circuit board, wherein the reflective sheet includes a plurality of diffusion lenses for diffusing light in a region corresponding to the plurality of light emitting diodes.

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

A liquid crystal display panel; A plurality of printed circuit boards disposed at regular intervals on a rear surface of the liquid crystal display panel; A plurality of light emitting diodes mounted on the printed circuit board at regular intervals; And a reflective sheet disposed on the printed circuit board, wherein the reflective sheet includes a plurality of diffusion lenses for diffusing light in a region corresponding to the plurality of light emitting diodes.

In addition, the manufacturing method of the liquid crystal display device,

Disposing a plurality of printed circuit boards having a plurality of light emitting diodes mounted on the bottom cover at regular intervals; Disposing a reflective sheet on the printed circuit board; And arranging a liquid crystal display panel on the reflective sheet, wherein the reflective sheet has a hole formed in a region corresponding to the light emitting diode, and a diffusion lens is formed on the hole using a nozzle. Characterized in that it comprises a.

According to the present invention, since the diffusion lens is integrally formed on the reflective sheet disposed on the printed circuit board and the bottom cover so as to correspond to the light emitting diode, there is an effect of achieving a uniform brightness as a whole.

In addition, the present invention is advantageous in thinning the liquid crystal display device because not only the diffusion plate of the general direct type liquid crystal display device can be deleted but also the gap between the light emitting diode and the liquid crystal display panel can be reduced.

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

FIG. 1 is an exploded perspective view illustrating a liquid crystal display device of a direct type according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the backlight unit cut along the line II ′ of FIG. 1.

1 and 2, the liquid crystal display according to the exemplary embodiment of the present invention is provided with a liquid crystal display panel 110 for displaying an image and a rear surface of the liquid crystal display panel 110 to provide light. It includes a backlight unit 120 to.

The liquid crystal display panel 110 includes a thin film transistor (TFT) array substrate and a color filter substrate bonded together to maintain a uniform cell gap facing each other, and a liquid crystal interposed between the thin film transistor array substrate and the color filter substrate. Layer.

Although not shown in the drawing, a driving unit (not shown) mounted with a driving circuit for supplying a driving signal to the liquid crystal display panel 110 is electrically connected to one side of the liquid crystal display panel 110 by a tape carrier package (TCP). do.

The driving unit is electrically connected to the liquid crystal display panel 110 to supply a control signal and a data signal to a plurality of gate lines (not shown) and data lines (not shown) formed in the liquid crystal display panel 110, thereby providing the liquid crystal display. The pixels of the panel 110 are driven.

The backlight unit 120 according to an embodiment of the present invention will be described as an example of a large size of 20 inches or more.

The backlight unit 120 includes a rectangular box shape bottom cover 170 having an upper surface, a printed circuit board 153 disposed at a predetermined interval on the bottom cover 170, and the printed circuit board 153. A light emitting diode 151 mounted on the reflective sheet 140, a reflective sheet 140 disposed on the printed circuit board 153 and the bottom cover 170, and a light disposed on the reflective sheet 140. Optical sheets 130 for diffusing and condensing the light.

The printed circuit board 153 is preferably a metal PCB in order to more easily conduct heat generated from the light emitting diode 151 to the bottom cover 170.

The light emitting diode 151 may be a combination of red, green, and blue light emitting diodes emitting red (R), green (G), and blue (B) light, or white light emitting diodes emitting white (w) light, or It can consist of a combination of these.

The reflective sheet 140 is disposed on the printed circuit board 153 and the bottom cover 170, and the light emitting diode 151 is irradiated with light emitted from the light emitting diode 151 toward the liquid crystal display panel 110. A hole (not shown) is formed in an area corresponding to. The reflective sheet 140 further includes a diffusion lens 141 covering the hole.

The diffusion lens 141 diffuses light incident from the light emitting diode 151 and is integrally formed at the time of manufacturing the reflective sheet 140.

The diffusion lens 141 is made of acrylic resin or transparent resin.

The diffusion lens 141 may have a curved shape, and the degree of bending may vary for each region.

As described above, the direct type liquid crystal display according to the exemplary embodiment of the present invention includes the light emitting diode 151 and the reflective sheet 140 disposed on the printed circuit board 153 and the bottom cover 170. Since the diffusion lens 141 is integrally formed to correspond to each other, a uniform luminance may be realized as a whole.

In addition, since the present invention can not only eliminate the diffusion plate of the liquid crystal display device of the general direct type but also can realize a smaller distance than the conventional LED 151 and the liquid crystal display panel 110, it is advantageous to thin the liquid crystal display device. Has an advantage.

3A and 3B illustrate a method of manufacturing a reflective sheet according to an embodiment of the present invention.

As shown in FIGS. 3A and 3B, the reflective sheet 140 according to the exemplary embodiment may include a plurality of holes 143 formed at regular intervals so that the light emitting diodes 151 of FIG. 2 may be exposed. It includes.

The reflective sheet 140 having the plurality of holes 143 is seated on the plate 145 having the plurality of protruding pins 147.

The protruding pins 147 of the plate 145 may correspond to the plurality of holes 143 of the reflective sheet 140, and the protruding pins 147 may have curved ends. That is, the reflective sheet 140 is aligned on the plate 145 so that the protruding pins 147 pass through the plurality of holes 143.

When the reflective sheet 140 is aligned on the plate 145, an acrylic resin or a transparent resin is coated on the protruding pin 147 using the nozzle 190.

When both acrylic resin or transparent resin is coated on the plurality of protruding pins 147, the plate 145 and the reflective sheet 140 are separated.

As shown in FIGS. 1 and 2, the diffuser lens 141 of FIG. 1 is formed on the separated reflective sheet 140.

In the above, a plurality of holes 143 are formed in the reflective sheet 140 to penetrate the light emitting diodes, and a diffusion lens (141 of FIG. 1) is formed in the plurality of holes 143 to emit light emitted from the light emitting diodes. Diffusion can be implemented to achieve a backlight unit having a uniform brightness.

In addition, since the present invention can not only eliminate the diffusion plate of the liquid crystal display device of the general direct type but also reduce the distance between the light emitting diode and the liquid crystal display panel, there is an advantageous effect in thinning the liquid crystal display device.

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 device of a direct type according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the backlight unit taken along the line II ′ of FIG. 1.

3A and 3B illustrate a method of manufacturing a reflective sheet according to an embodiment of the present invention.

Claims (8)

A plurality of printed circuit boards arranged at regular intervals; A plurality of light emitting diodes mounted on the printed circuit board at regular intervals; And A reflective sheet disposed on the printed circuit board, The reflective sheet includes a plurality of diffusion lenses for diffusing light in a region corresponding to the plurality of light emitting diodes. According to claim 1, And a hole is formed in the reflective sheet to expose the plurality of light emitting diodes, and the diffusion lens is integrally formed with the reflective sheet in a curved shape covering the hole. According to claim 1, The diffusion lens is a backlight unit, characterized in that made of any one of acrylic resin and transparent resin. A liquid crystal display panel; A plurality of printed circuit boards disposed on the rear surface of the liquid crystal display panel at regular intervals; A plurality of light emitting diodes mounted on the printed circuit board at regular intervals; And A reflective sheet disposed on the printed circuit board, The reflective sheet includes a plurality of diffusion lenses for diffusing light in a region corresponding to the plurality of light emitting diodes. The method of claim 4, wherein And a hole is formed in the reflective sheet to expose the plurality of light emitting diodes, and the diffusion lens is integrally formed with the reflective sheet in a curved shape covering the hole. The method of claim 4, wherein The diffusion lens is one of an acrylic resin and a transparent resin. Disposing a plurality of printed circuit boards having a plurality of light emitting diodes mounted on the bottom cover at regular intervals; Disposing a reflective sheet on the printed circuit board; And Disposing a liquid crystal display panel on the reflective sheet; The reflective sheet may include forming a hole in a region corresponding to the light emitting diode, and forming a diffusion lens on the hole by using a nozzle. The method of claim 7, wherein Forming the diffusion lens is, Providing the reflective sheet having the holes formed thereon; Aligning the reflective sheet on a plate having a protruding pin penetrating the hole; And And forming the diffusion lens in the hole by using a nozzle.
KR1020070120535A 2007-11-23 2007-11-23 Backlight unit and liquid crystal display having thesame, and method thereof KR20090053631A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020070120535A KR20090053631A (en) 2007-11-23 2007-11-23 Backlight unit and liquid crystal display having thesame, and method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020070120535A KR20090053631A (en) 2007-11-23 2007-11-23 Backlight unit and liquid crystal display having thesame, and method thereof

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KR20090053631A true KR20090053631A (en) 2009-05-27

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8636400B2 (en) 2011-01-19 2014-01-28 Samsung Display Co., Ltd. Display device
KR20150015633A (en) * 2013-07-31 2015-02-11 삼성디스플레이 주식회사 Display device
WO2023008649A1 (en) * 2021-07-29 2023-02-02 삼성전자주식회사 Display device
US11656496B2 (en) 2021-07-29 2023-05-23 Samsung Electronics Co., Ltd. Display apparatus

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8636400B2 (en) 2011-01-19 2014-01-28 Samsung Display Co., Ltd. Display device
KR20150015633A (en) * 2013-07-31 2015-02-11 삼성디스플레이 주식회사 Display device
WO2023008649A1 (en) * 2021-07-29 2023-02-02 삼성전자주식회사 Display device
US11656496B2 (en) 2021-07-29 2023-05-23 Samsung Electronics Co., Ltd. Display apparatus

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