WO2009104846A1 - Direct lighting type backlight unit using led lamps - Google Patents

Direct lighting type backlight unit using led lamps Download PDF

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Publication number
WO2009104846A1
WO2009104846A1 PCT/KR2008/004781 KR2008004781W WO2009104846A1 WO 2009104846 A1 WO2009104846 A1 WO 2009104846A1 KR 2008004781 W KR2008004781 W KR 2008004781W WO 2009104846 A1 WO2009104846 A1 WO 2009104846A1
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WO
WIPO (PCT)
Prior art keywords
light
backlight unit
light emitting
emitting diode
direct
Prior art date
Application number
PCT/KR2008/004781
Other languages
French (fr)
Inventor
Jung-Gee Lee
Original Assignee
Heesung Electronics Co., Ltd.
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 Heesung Electronics Co., Ltd. filed Critical Heesung Electronics Co., Ltd.
Publication of WO2009104846A1 publication Critical patent/WO2009104846A1/en

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Classifications

    • 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
    • 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
    • G02F1/133605—Direct backlight including specially adapted reflectors
    • 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
    • G02F1/133607—Direct backlight including a specially adapted diffusing, scattering or light controlling members the light controlling member including light directing or refracting elements, e.g. prisms or lenses
    • 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

Definitions

  • the present invention relates to a direct- lighting backlight unit using a light emitting diode (LED) lamps, and more particularly, to a direct-lighting backlight unit that improves uniformity of an image by arranging prism type reflective members to define rhombus spaces and disposing LED lamps in the rhombus spaces.
  • LED light emitting diode
  • a backlight unit for a liquid crystal display uses a fluorescent lamp such as a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (HCFL), and an external electrode fluorescent lamp, an LED device, or an electro luminescence (EL) device as a light source thereof.
  • the backlight units are classified into edge-lighting type backlight units and direct- lighting type backlight units in accordance with a light source disposing manner.
  • the edge-lighting type backlight unit is relatively thin and thus it is mainly used as a light source for an LCD of a laptop computer or a desktop computer.
  • the direct-lighting type backlight unit has relatively high light efficiency and thus it is generally used as a light source of a large-sized display such as an LCD TV.
  • the direct-lighting backlight unit using the LED lamp has a problem of deteriorating the light uniformity due to the luminance difference caused by variation of front light emitting rate according to the incident angle of the light on the diffusing plate. Disclosure of Invention Technical Problem
  • the present invention provides a direct-lighting backlight unit emitting light frontward using a plurality of light emitting diodes, including: a light emitting diode light source module including a cover bottom frame for mounting the light emitting diode lamps, a protruded reflective member that divides the top surface of the cover bottom frame to define LED lamp mounting spaces each formed in a rhombus, and a plurality of the light emitting diode lamps mounted in the respective LED lamp mounting spaces; and a pattern diffusing plate that improves uniformity by diffusing light emitted from the LED lamps and incident through the light emitting diode light source module.
  • a light emitting diode light source module including a cover bottom frame for mounting the light emitting diode lamps, a protruded reflective member that divides the top surface of the cover bottom frame to define LED lamp mounting spaces each formed in a rhombus, and a plurality of the light emitting diode lamps mounted in the respective LED lamp mounting spaces; and a pattern diffusing plate that improves
  • the protruded reflective member may be formed in a triangular prism having a bottom side angle ranging from 45° to 64° and a reflective property of 95% or more respect to the light emitted from the corresponding Led lamp.
  • FIG. 1 is a perspective view of a direct- lighting backlight unit using LED lamps a ccording to an embedment of the present invention.
  • FIG. 2 is a schematic view illustrating a top plane arrangement structure of LED lamps according to an embodiment of the present invention.
  • FIG. 3 is a schematic view illustrating a protruded reflective member according to an embodiment of the present invention.
  • FIG. 5 is an enlarged view of an undersurface pattern of a diffusing plate according to an embodiment of the present invention.
  • FIGS. 6 and 7 are views illustrating optical properties of a direct- lighting backlight unit using LED lamps according to an embodiment of the present invention.
  • FIGS. 8 to 10 are views illustrating optical properties of a typical direct- lighting backlight unit using LED lamps.
  • LED light source module 112 Cover bottom frame
  • FIG. 1 is a perspective view of a direct-lighting backlight unit using LED lamps according to an embodiment of the present invention
  • FIG. 2 is a schematic view illustrating a top plane arrangement structure of LED lamps according to an embodim ent of the present invention
  • FIG. 3 is a schematic view illustrating a protruded reflective member according to an embodiment of the present invention
  • FIG. 4 is a side sectional view of a protruded reflective member according to an embodiment of the present invention
  • FIG. 5 is an enlarged view of an undersurface pattern of a diffusing plate according to an embodiment of the present invention.
  • a direct-lighting backlight unit 100 using LED lamps includes an LED light source module 110 for mounting LED lamps 114 that functions as a light source instead of a CCFL and a pattern diffusing plate 120 for uniformly diffusing light emitted from the LED lamps 114.
  • the LED light source module 110 includes a cover bottom frame 112 for mounting the LED lamps, a protruded reflective member 116 that divides the top surface of the cover bottom frame 112 to define LED lamp mounting spaces each formed in a rhombus, and a plurality of the LED lamps 114 mounted in the respective LED lamp mounting spaces.
  • the LED lamps mounted in the respective LED lamp mounting spaces of the LED light source module are arranged in a triangular arrangement as shown in FIG. 2 to minimize a gap between the LED lamps 114 and improve the uniformity.
  • A a distance between the adjacent LED lamps 114 located at an identical horizontal line
  • B a distance between adjacent horizontal lines
  • C a distance between the closest LED lamps on the respective adjacent horizontal lines
  • the protruded reflective member 116 defining the LED mounting spaces protrudes in a prism-shape having a triangular side section and is arranged to interest in left and right oblique directions.
  • the LED lamps 114 are mounted in the respective mounting spaces as shown in FIG. 3.
  • Each of the LED lamps 114 includes red, green, green, and blue LEDs as shown in FIG. 2 to emit white light.
  • FIGS. 6 and 7 are views illustrating optical properties of the direct-lighting backlight unit using the LED lamps according to an embodiment of the present invention.
  • front light emission of about 100% for the light incident in a vertical direction on the pattern diffusing plate 120 provided at the un- dersurface thereof with the prism patterns Pl is realized, and front light emission of about 100% for the light incident in a direction of 15° is realized.
  • front light emission of about 100% for the light incident in a direction of 30° is realized.
  • the backlight unit 100 of the present invention has the better light efficiency and the lower luminance difference than the related art backlight unit of the present invention. That is, the backlight unit of the present invention is improved in the light uniformity.

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

Abstract

A direct-lighting backlight unit that improves uniformity of an image by arranging prism type reflective members to define rhombus spaces and disposing LED lamps in the rhombus spaces is provided. The direct-lighting backlight unit includes a light emitting diode light source module including a cover bottom frame for mounting the light emitting diode lamps, a protruded reflective member that divides the top surface of the cover bottom frame to define LED lamp mounting spaces each formed in a rhombus, and a plurality of the light emitting diode lamps mounted in the respective LED lamp mounting spaces, and a pattern diffusing plate that improves uniformity by diffusing light emitted from the LED lamps and incident through the light emitting diode light source module. A triangular arrangement of the LEDs minimizes a gap between the LEDs to improve the uniformity and light in an oblique angle direction of the LEDs is reflected upward by protruded reflective members to reduce generation of dark portions between the LEDs. In addition, the reflected light and light traveling upward are widely emitted by the undersurface pattern of the diffusing plate, thereby improving the uniformity and luminance.

Description

Description
DIRECT LIGHTING TYPE BACKLIGHT UNIT USING
LED LAMPS
Technical Field
[1] The present invention relates to a direct- lighting backlight unit using a light emitting diode (LED) lamps, and more particularly, to a direct-lighting backlight unit that improves uniformity of an image by arranging prism type reflective members to define rhombus spaces and disposing LED lamps in the rhombus spaces. Background Art
[2] Generally, a backlight unit for a liquid crystal display (LCD) uses a fluorescent lamp such as a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (HCFL), and an external electrode fluorescent lamp, an LED device, or an electro luminescence (EL) device as a light source thereof. The backlight units are classified into edge-lighting type backlight units and direct- lighting type backlight units in accordance with a light source disposing manner. The edge-lighting type backlight unit is relatively thin and thus it is mainly used as a light source for an LCD of a laptop computer or a desktop computer. The direct-lighting type backlight unit has relatively high light efficiency and thus it is generally used as a light source of a large-sized display such as an LCD TV.
[3] As shown in FIG. 8, a typical direct-lighting backlight unit 10 includes an array of
LED lamps 12 mounted on a cover bottom 11 and a diffusing plate 13 that improve light uniformity by diffusing the light emitted from the LED lamps.
[4] Unlike a fluorescent lamp that emits light in all directions, the LED lamp 12 emits the light only in a specific direction and thus front light emission rate varies according to the angle. Therefore, the light uniformity of the LED lamp 12 is deteriorated due to a luminance difference. For example, as shown in FIG. 9, when the diffusing plate 13 is used in the direct- lighting backlight unit 10 using the LED lamp 12, the front light emission rates in a vertical direction and at 15° and 30° is about 73%, 91%, and 73%, respectively. Therefore, a luminance difference between a highest value and a lowest value increases as shown in FIG. IQ
[5] That is, the direct-lighting backlight unit using the LED lamp has a problem of deteriorating the light uniformity due to the luminance difference caused by variation of front light emitting rate according to the incident angle of the light on the diffusing plate. Disclosure of Invention Technical Problem
[6] Accordingly, the present invention has been made in an effort to solve the above- described problems. It is an object of the present invention to provide a direct-lighting backlight unit that improves uniformity of an image by arranging prism type reflective members to define rhombus spaces and disposing LED lamps in the rhombus spaces.
[7] It is another object of the present invention to provide a direct-lighting backlight unit that can improve the light uniformity and luminance by forming a prism pattern having a rounded peak on a diffusing plate. Technical Solution
[8] To achieve the object, the present invention provides a direct-lighting backlight unit emitting light frontward using a plurality of light emitting diodes, including: a light emitting diode light source module including a cover bottom frame for mounting the light emitting diode lamps, a protruded reflective member that divides the top surface of the cover bottom frame to define LED lamp mounting spaces each formed in a rhombus, and a plurality of the light emitting diode lamps mounted in the respective LED lamp mounting spaces; and a pattern diffusing plate that improves uniformity by diffusing light emitted from the LED lamps and incident through the light emitting diode light source module.
[9] The protruded reflective member may be formed in a triangular prism having a bottom side angle ranging from 45° to 64° and a reflective property of 95% or more respect to the light emitted from the corresponding Led lamp.
[10] The pattern diffusing plate may be provided at an undersurface thereof with a prism pattern having a rounded peak with a radius of curvature of 50-100/M and a peak angle of 60-100° defined by extending oblique sides.
Advantageous Effects
[11] According to the direct- lighting backlight unit of the present invention, a triangular arrangement of the LEDs minimizes a gap between the LEDs to improve the uniformity and light in an oblique angle direction of the LEDs is reflected upward by protruded reflective members to reduce generation of dark portions between the LEDs. In aάϊtion, the reflected light and light traveling upward are widely emitted by the undersurface pattern of the diffusing plate, thereby improving the uniformity and luminance. Brief Description of the Drawings [12] FIG. 1 is a perspective view of a direct- lighting backlight unit using LED lamps a ccording to an embedment of the present invention.
[13] FIG. 2 is a schematic view illustrating a top plane arrangement structure of LED lamps according to an embodiment of the present invention.
[14] FIG. 3 is a schematic view illustrating a protruded reflective member according to an embodiment of the present invention.
[15] FIG. 4 is a side sectional view of a protruded reflective member according to an embodiment of the present invention.
[16] FIG. 5 is an enlarged view of an undersurface pattern of a diffusing plate according to an embodiment of the present invention.
[17] FIGS. 6 and 7 are views illustrating optical properties of a direct- lighting backlight unit using LED lamps according to an embodiment of the present invention.
[18] FIGS. 8 to 10 are views illustrating optical properties of a typical direct- lighting backlight unit using LED lamps.
[19] <DESCRIPTION OF THE SYMBOLS IN MAIN PORTIONS OF THE
DRAWINGS>
[20] 100: Direct-lighting backlight unit
[21] 110: LED light source module 112: Cover bottom frame
[22] 114: LED lamp 116: Protruded reflective member
[23] 120: Pattern diffusing plate
Best Mode for Carrying Out the Invention
[24] Technical solutions achieved by the present invention and embodiments of the present invention will now be more apparent by exemplary embodiments that will be described more fully with reference to the accompanying drawings. The exemplary embodiments may, however, be exemplified and should not be construed as being limited to the embodiments set forth herein
[25] FIG. 1 is a perspective view of a direct-lighting backlight unit using LED lamps according to an embodiment of the present invention, and FIG. 2 is a schematic view illustrating a top plane arrangement structure of LED lamps according to an embodim ent of the present invention. FIG. 3 is a schematic view illustrating a protruded reflective member according to an embodiment of the present invention, FIG. 4 is a side sectional view of a protruded reflective member according to an embodiment of the present invention, and FIG. 5 is an enlarged view of an undersurface pattern of a diffusing plate according to an embodiment of the present invention.
[26] Referring to FIG. 1, a direct-lighting backlight unit 100 using LED lamps according to the present invention includes an LED light source module 110 for mounting LED lamps 114 that functions as a light source instead of a CCFL and a pattern diffusing plate 120 for uniformly diffusing light emitted from the LED lamps 114.
[27] The LED light source module 110 includes a cover bottom frame 112 for mounting the LED lamps, a protruded reflective member 116 that divides the top surface of the cover bottom frame 112 to define LED lamp mounting spaces each formed in a rhombus, and a plurality of the LED lamps 114 mounted in the respective LED lamp mounting spaces.
[28] The LED lamps mounted in the respective LED lamp mounting spaces of the LED light source module are arranged in a triangular arrangement as shown in FIG. 2 to minimize a gap between the LED lamps 114 and improve the uniformity. When a distance between the adjacent LED lamps 114 located at an identical horizontal line is A, a distance between adjacent horizontal lines is B, and a distance between the closest LED lamps on the respective adjacent horizontal lines is C, there is a relationship such as the following equation 1.
[29] [Equation 1]
Figure imgf000005_0001
[31] In adition, as shown in FIGS. 3 and 4, the protruded reflective member 116 defining the LED mounting spaces protrudes in a prism-shape having a triangular side section and is arranged to interest in left and right oblique directions. The LED lamps 114 are mounted in the respective mounting spaces as shown in FIG. 3. Each of the LED lamps 114 includes red, green, green, and blue LEDs as shown in FIG. 2 to emit white light.
[32] In FIG. 4, an angle θ of a bottom side of the protruded reflective member 116 ranges a from 45° to 64° and provides a reflective property of 95% or more with respect to light emitted from the corresponding LED lamp 114. [33] As shown in FIGS. 1 and 5, the pattern diffusing plate 120 is provided at an un- dersurface thereof with continuous prism patterns Pl. Unlike a typical prism pattern, a peak of the prism pattern Pl formed on the undersurface of the pattern diffusing plate 120 according to the present invention is rounded to have a radius of curvature of about 50-100/M. A peak angle θ defined by extending the oblique sides of the prism b pattern Pl ranges from 60° to 100°. [34] The following will describe optical properties of the direct- lighting backlight unit 100 using the LED lamps according to the present invention.
[35] FIGS. 6 and 7 are views illustrating optical properties of the direct-lighting backlight unit using the LED lamps according to an embodiment of the present invention.
[36] Referring to FIG. 6, In the direct-lighting backlight unit 100 using the LED lamps according to the present invention, front light emission of about 100% for the light incident in a vertical direction on the pattern diffusing plate 120 provided at the un- dersurface thereof with the prism patterns Pl is realized, and front light emission of about 100% for the light incident in a direction of 15° is realized. In aάϊtion, front light emission of about 100% for the light incident in a direction of 30° is realized.
[37] Since the front light emission of about 100% is realized within a relatively wide angle range, as shown in FIG. 7, a difference between the highest luminance and the lowest luminance is reduced and thus the luminance that is generally uniform can be realized. .
[38] Furthermore, when comparing the optical properties (FIGS. 6 and 7) with the optical properties (FIGS. 9 and 10) of the related art, the backlight unit 100 of the present invention has the better light efficiency and the lower luminance difference than the related art backlight unit of the present invention. That is, the backlight unit of the present invention is improved in the light uniformity.
[39] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

Claims
[1] A direct- lighting backlight unit emitting light frontward using a plurality of light emitting diodes, comprising: a light emitting diode light source module comprising a cover bottom frame for mounting the light emitting diode lamps, a protruded reflective member that divides the top surface of the cover bottom frame to define LED lamp mounting spaces each formed in a rhombus, and a plurality of the light emitting diode lamps mounted in the respective LED lamp mounting spaces; and a pattern diffusing plate that improves uniformity by diffusing light emitted from the LED lamps and incident through the light emitting diode light source module.
[2] The direct-lighting backlight unit of claim 1, wherein the protruded reflective member is formed in a triangular prism having a bottom side angle ranging from 45° to 64° and a reflective property of 95% or more respect to the light emitted from the corresponding Led lamp.
[3] The direct-lighting backlight unit of claim 1, wherein the pattern diffusing plate is provided at an undersurface thereof with a prism pattern having a rounded peak with a radius of curvature of 50-100/M and a peak angle of 60-100° defined by extending oblique sides.
PCT/KR2008/004781 2008-02-20 2008-08-18 Direct lighting type backlight unit using led lamps WO2009104846A1 (en)

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CN103883931B (en) * 2012-12-21 2018-03-02 深圳日光显示技术有限公司 Backlight module
CN105137652A (en) * 2015-07-20 2015-12-09 京东方科技集团股份有限公司 Diffuser plate, backlight module, and display device
CN115167035B (en) * 2022-09-08 2022-12-23 惠科股份有限公司 Backlight module and display device
US11871518B1 (en) 2023-06-19 2024-01-09 HKC Corporation Limited Backlight module and display device

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JP2007012586A (en) * 2005-06-30 2007-01-18 Lg Phillips Lcd Co Ltd Backlight unit
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KR20070114428A (en) * 2006-05-29 2007-12-04 삼성전자주식회사 Backlight assembly

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JP2006332024A (en) * 2005-04-27 2006-12-07 Mitsubishi Electric Corp Planar light source device
JP2007012586A (en) * 2005-06-30 2007-01-18 Lg Phillips Lcd Co Ltd Backlight unit
US20070070625A1 (en) * 2005-09-23 2007-03-29 Lg.Philips Lcd Co., Ltd. Backlight assembly and liquid crystal display module using the same
KR20070114428A (en) * 2006-05-29 2007-12-04 삼성전자주식회사 Backlight assembly

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