KR20090025566A - Lcd backlight sturucture for high brightness and very low brightness - Google Patents

Lcd backlight sturucture for high brightness and very low brightness Download PDF

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Publication number
KR20090025566A
KR20090025566A KR1020070090519A KR20070090519A KR20090025566A KR 20090025566 A KR20090025566 A KR 20090025566A KR 1020070090519 A KR1020070090519 A KR 1020070090519A KR 20070090519 A KR20070090519 A KR 20070090519A KR 20090025566 A KR20090025566 A KR 20090025566A
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KR
South Korea
Prior art keywords
cold cathode
lamp
guide plate
light guide
brightness
Prior art date
Application number
KR1020070090519A
Other languages
Korean (ko)
Inventor
하홍주
Original Assignee
(주)테라전자
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 (주)테라전자 filed Critical (주)테라전자
Priority to KR1020070090519A priority Critical patent/KR20090025566A/en
Publication of KR20090025566A publication Critical patent/KR20090025566A/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
    • G02B6/0033—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
    • 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]
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133524—Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0626—Adjustment of display parameters for control of overall brightness

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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)
  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Planar Illumination Modules (AREA)

Abstract

An LCD backlight structure for high brightness and very low brightness is provided to arrange additional LED(Light Emitting Diode)s in parallel with a cold cathode lamp to increase the amount of light incident on a light guide plate, thereby improving brightness of an LCD. A light guide plate(30) is positioned in a lower part of an LCD panel(10). A plurality of cold cathode lamps(20) is installed at both sides of the light guide plate. A lamp reflective plate surrounds a plurality of cold cathode lamps with a reflective type. A reflector is adhered to a rear side of the light guide plate. An LED lamp(21) is arranged in parallel with the cold cathode lamp. The reflector surrounds the LED lamp. The LED lamp is arranged after the cold cathode lamp. The LED lamp guides light to the light guide plate by using an optical waveguide.

Description

LCD Backlight Sturucture for High Brightness And Very Low Brightness}

 And

The present invention relates to a liquid crystal display device, and more particularly, by additionally arranging an LED light source in parallel with a cold cathode lamp to increase the amount of light input to the light guide plate, thereby improving the brightness of the LCD, the cold cathode lamp alone can not reach A backlight structure of a liquid crystal display device that emits brightness of brightness.

In general, LCDs are light-receiving elements that do not emit light by themselves, and because they cannot be used in dark places, the LCD displays an image using a backlight attached to the back of the liquid crystal panel. The direct backlight method and the edge method are widely used for the backlight method, and the direct method is a method of directly dimming the front of the panel by placing a light source on the bottom of the LCD panel. The light source is mainly an electroluminescence (EL). Cold cathode lamps are used, and the edge method uses a light source on one side or both sides of the LCD panel to reflect and diffuse light on the light guide plate and the reflecting plate, and a cold cathode tube, a hot cathode tube, and a fluorescent lamp are used as the light source. have. Today's LCDs with high definition and large size use many lamps to have bright brightness and high light uniformity, using an edge method in which the lamps are located on both sides of the light guide plate. 1 is a cross-sectional view showing a backlight structure according to the prior art.

The light guide plate 30 is positioned under the LCD panel 10 and the LCD panel 10, and the lamp reflector 40 is formed in a semicircular shape on both sides of the light guide plate 30 to face the light guide plate 30. The reflecting plate 50 is attached below the light guide plate 30.

The operation of the conventional backlight configured as described above is as follows.

Light emitted from the lamps 20 installed on both sides of the light guide plate 30 is reflected by the lamp reflector 40 and is incident on the light guide plate 30, or the light of the lamp 40 is directly incident on the light guide plate 30. The light is reflected by the light guide plate 50 and passes through the back of the LCD panel 10. In addition, the light leaked to the rear surface of the light guide plate 30 is transmitted back to the light guide plate 30 by the reflective plate 30.

Existing cold cathode lamps have a diameter of several millimeters (mm), so it is difficult to arrange a new cold cathode even if there is a free space on both sides of the light guide plate. By placing an LED lamp in this space, the amount of light projected onto the light guide plate is increased to improve the brightness of the LCD.

Cold-cathode lamps are lamps that use discharge, and since the discharge does not form under the minimum current required to maintain the discharge, the lamp does not work and discharge is very unstable under a certain operating current. Is reduced to less than one tenth of the maximum current, making it difficult to stably drive the cold cathode lamp. Therefore, the backlight of the liquid crystal display using only the cold cathode lamp is extremely difficult to drive extremely low luminance (less than one hundredth of the maximum brightness).

Such a problem can be arranged in parallel with a cold cathode lamp to maintain an operating state even at one-hundredth of the maximum brightness.

Accordingly, an object of the present invention is to provide a backlight structure of a liquid crystal display device by adding an LED light source in parallel with a cold cathode lamp as a light source of the backlight to increase the brightness of the backlight and exhibit stable ultra-low brightness driving characteristics.

In order to achieve the above object, the present invention is characterized in that the cold cathode fluorescent lamps provided on both sides of the light guide plate, a plurality of LED lamps arranged in parallel with the cold cathode lamps, and a lamp reflecting plate surrounding them are formed.

In addition, the LED lamp disposed in parallel with the cold cathode lamp as a driving method is characterized by being divided into a high brightness operating region to drive simultaneously with the cold cathode lamp and an ultra-low brightness operating region to drive the LED lamp alone.

Hereinafter, the backlight structure of the liquid crystal display according to the present invention will be described in detail with reference to FIG. 2. The same reference numerals are given to the same parts as the conventional parts.

As described above, the present invention increases the brightness of the backlight by adding an LED light source in parallel with the cold cathode lamp as a light source of the backlight, on the contrary, increases when the ultra-low brightness driving characteristics are required and uses the minimum operating current characteristics of the LED. It exhibits ultra low brightness characteristics of less than one hundredth of the brightness standard of the backlight.

Hereinafter, the backlight structure of the liquid crystal display according to the present invention will be described in detail with reference to FIG. 2. The same reference numerals are given to the same parts as the conventional parts.

As shown, the LCD panel 10 and both sides of the light guide plate 30 under the LCD panel 10 are in parallel between a plurality of cold cathode lamps, and the LED lamp 21 is parallel to the direction of the cold cathode lamp 20. The cold cathode lamp and LED are backlit by the lamp reflector.

Hereinafter, the backlight operation of the liquid crystal display device of the present invention will be described.

In high-brightness mode, driving the cold cathode lamp and LED lamp at the same time increases the brightness of the backlight.If ultra-low brightness mode is required, such as when the LCD is to be seen in nighttime operation or in very dark surroundings, only the LED lamp is used. In this way, low-brightness driving of less than one hundredth of the maximum brightness can be realized.

1 is a cross-sectional view showing a backlight structure according to the prior art.

2 is a cross-sectional view showing a backlight structure of the present invention.

Figure 3 is a cold cathode lamp and LED lamp structure of the present invention

4 is a LED lamp structure of the present invention

Claims (3)

A light guide plate disposed under the LCD panel, a plurality of cold cathode lamps respectively provided on both sides of the light guide plate, a lamp reflector surrounding the plurality of lamps in a reflective type, and a reflector attached to a rear surface of the light guide plate. The backlight structure comprising a light source including an LED lamp disposed in parallel with the cold cathode lamp and a reflecting plate surrounding the cold cathode lamp. The backlight structure according to claim 1, wherein the LED lamp is disposed behind the cold cathode lamp and the light is guided to the light guide plate using an optical waveguide. The dual operation method of the structure of claim 1, wherein the high luminance operation region for operating the LED lamps simultaneously with the cold cathode lamps and the ultra low luminance operating region for operating the LED lamps alone in the high luminance operation.
KR1020070090519A 2007-09-06 2007-09-06 Lcd backlight sturucture for high brightness and very low brightness KR20090025566A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020070090519A KR20090025566A (en) 2007-09-06 2007-09-06 Lcd backlight sturucture for high brightness and very low brightness

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020070090519A KR20090025566A (en) 2007-09-06 2007-09-06 Lcd backlight sturucture for high brightness and very low brightness

Publications (1)

Publication Number Publication Date
KR20090025566A true KR20090025566A (en) 2009-03-11

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Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020070090519A KR20090025566A (en) 2007-09-06 2007-09-06 Lcd backlight sturucture for high brightness and very low brightness

Country Status (1)

Country Link
KR (1) KR20090025566A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101224607B1 (en) * 2012-05-31 2013-01-22 주식회사 이아이라이팅 Multiplex reflection type optical module
CN103148362A (en) * 2011-12-06 2013-06-12 郭锦标 Plane light source device and manufacturing method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103148362A (en) * 2011-12-06 2013-06-12 郭锦标 Plane light source device and manufacturing method thereof
KR101224607B1 (en) * 2012-05-31 2013-01-22 주식회사 이아이라이팅 Multiplex reflection type optical module

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E601 Decision to refuse application