GB2311643A - Backlight for a liquid crystal display - Google Patents

Backlight for a liquid crystal display Download PDF

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Publication number
GB2311643A
GB2311643A GB9705790A GB9705790A GB2311643A GB 2311643 A GB2311643 A GB 2311643A GB 9705790 A GB9705790 A GB 9705790A GB 9705790 A GB9705790 A GB 9705790A GB 2311643 A GB2311643 A GB 2311643A
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United Kingdom
Prior art keywords
light emitting
zns
backlight assembly
emitting phosphor
group
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
GB9705790A
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GB9705790D0 (en
Inventor
Young-Rag Do
Young-Chul You
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Samsung SDI Co Ltd
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Samsung Display Devices Co Ltd
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Filing date
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Application filed by Samsung Display Devices Co Ltd filed Critical Samsung Display Devices Co Ltd
Publication of GB9705790D0 publication Critical patent/GB9705790D0/en
Publication of GB2311643A publication Critical patent/GB2311643A/en
Withdrawn legal-status Critical Current

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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
    • G02F1/133621—Illuminating devices providing coloured light
    • 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
    • G02F1/133604—Direct backlight with lamps
    • 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
    • G02F1/133617—Illumination with ultraviolet light; Luminescent elements or materials associated to the cell
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/3413—Details of control of colour illumination sources
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/342—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/70—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr
    • H01J61/76—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr having a filling of permanent gas or gases only
    • H01J61/78—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr having a filling of permanent gas or gases only with cold cathode; with cathode heated only by discharge, e.g. high-tension lamp for advertising
    • 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
    • G02F2202/00—Materials and properties
    • G02F2202/04—Materials and properties dye
    • G02F2202/046—Materials and properties dye fluorescent
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/024—Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • Mathematical Physics (AREA)
  • Computer Hardware Design (AREA)
  • Theoretical Computer Science (AREA)
  • Liquid Crystal (AREA)
  • Luminescent Compositions (AREA)
  • Planar Illumination Modules (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Illuminated Signs And Luminous Advertising (AREA)

Description

2311643 CONSECUTIVE ILLUMINATING BACKLIGHT ASSEMBLY FOR LCD EMPLOYING
FLUORESCENT LAYER Backcround of the Invention The present invention relates to a backlight assembly for a liquid crystal display (LCD), and more particularly, to a consecutive illuminating backlight assembly for an LCD employing a fluorescent layer.
Generally, an LCD is roughly divided into an LCD panel and a backlight assembly. Here, the LCD panel is interposed between two polarizing plates and includes two substrates, a liquid crystal layer interposed between two substrates and a color filter layer formed on one side of the substrate. The LCD is called a light receiving device as a color image is formed by filtering light emitted from the backlight assembly is with the color filter. However, the color filter used for the image formation decreases amount of emitted light, lowering efficiency in use of light emitted from the backlight assembly.
To solve the above problem, an LCD having a fluorescent layer, as shown in FIG. 1, has been developed. As shown in FIG. 1, there is provided a fluorescent layer 11 on the front of a liquid crystal assembly 13, on which red (R), green (G) and blue (B) light emitting phosphors are coated. Also, a black matrix layer 14 made of graphite is formed between the phosphors.
In the LCD having the above structure, a light!Do emitted from a backlight source (not shown) passes through a transnarent electrode 15 and then passes through the liquid 1 crystal assembly 13, depending on whether voltage is applied at that portion, to reach the fluorescent layer 11. The light arriving at the fluorescent layer 11 excites the designated phosphors to be illuminated. Since the above LCD realizes a color image by directly illuminating the phosphors, there is no need to interpose a color filter therein. As a result, the amount of light passing through the LCD increases, resulting in a sharper contrast.
However, in a conventional backlight assembly, a light transmitting plate (not shown) provided at the rear of the LCD panel distributes light emitted from the light source toward the LCD panel. However, it is impossible to provide equal illumination throughout the entire LCD panel using the light transmitting plate.
is Furthermore, the conventional backlight assembly illuminates the entire rear side of the LCD panel, thereby wasting electrical energy.
Summary of the Invention
It is an object of the present invention to provide a backlight assembly for an LCD employing a fluorescent layer, for consecutively and repeatedly scanning to the rear side of an LCD panel, thereby creating a continuous screen using an afterimage effect of the eyes without wasting electrical power.
To achieve the above object, there is provided a consecutive illuminating backlight assembly for an LCD employing a fluorescent layer comprising: a plurality of cold 2 cathode fluorescent tubes stacked in parallel and having a length corresponding to the length of a LCD panel; and support plates for supporting the cold cathode fluorescent tubes and providing electrical connections to the cold cathode fluorescent tubes at both ends thereof, wherein the cold cathode fluorescent tubes are illuminated consecutively to form a continuous image on a screen, and emit violet rays having a wavelength of 38042Onm to excite phosphors of the fluorescent layer.
Here, it is preferable that the cold cathode fluorescent tube is incorporated with at least one element selected from the group consisting of Co, Ni and Fe, and comprises at least one phosphor selected from the group consisting of SrP207:Eu, SrMgP207:Eu, Sr3 (P04) 2:Eu, (Sr,Ba)A'2S'20,:Eu, Y2S'20.7:Ce, is ZnGa204:Li,Ti, YTaO,:Nb, CaWO,, BaFX:Eu (wherein X is halogen), (Sr,Ca)0.2B20.:EU, SrAL-2011:Eu and Y2S'O,:Ce.
Also, there is -Provided a consecutive illuminating backlight assembly for an LCD employing a fluorescent layer comprising: a plurality of light emitting diodes as a light source; and a plurality of support plates stacked in parallel so that each support plate supports a line of the light emitting diodes, wherein the light emitting diodes are consecutively illuminated by lines to form a continuous image on a screen, and emits violet rays having a wavelength of 38Onm to 420nm to excite phosphors of the fluorescent layer.
Preferably, the light emitting diode is formed of GaN semiconductor, and the fluorescent layer consists of a blue light emitting phosphor, a green light emitting phosphor, and 3 a red light emitting phosphor, wherein the blue light emitting phosphor is at least one compound selected from the group consisting of Sr,o (P01) C'1-2:EU2, (Sr,Ca..1) 1. (P04) 6C12: SU2, Sr3M9S'20,:EU2, Ba3M9S '20.: EU2,' ZnS:Ag,Cl, ZnS:Ag,Al, ZnS:Ag, ZnO:Ag and ZnS:Ag,Ga, the green light emitting phosphor is at least one compound selected from the group consisting of S rAl 2 01: EU2 +, SrGa2S1:EU2,, Y3A1,01-2:Ce 3' ZnS:Cu, ZnS:Cu,Al, CdS:Cu,Al and ZnS:Cu,Au, Al, and the red light emitting phosphor is at least one compound selected from the group consisting of 6MgO-AS20.:Mn, 3.5MgO.O.5MgF2-Ge02:Mn, Sry2S1:Eu, Sry2SI:Mn, K5EuM1)41 Y202S:Eu and Y203:Eu.
Brief Description of the Drawings
The above objects and advantages of the present invention is will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings in which:
FIG. 1 is a schematic structural diagram of a typical liquid crystal display (LCD) having a fluorescent layer for illustrating a backlight assembly; FIG. 2 is a schematic perspective view of an LCD having a backlight assembly according to a preferred embodiment of the mresent invention; and FIG. 3 is a schematic perspective view of the LCD having a backlight assembly according to another preferred embodiment of the present invention.
Detailed Description of the Invention
4 Referring to FIG. 2, a backlight assembly 30 of the present invention is provided at the rear of a liquid crystal display (LCD) panel 20. The LCD panel 20 includes a lower substrate 21, an upper substrate 22, a plurality of transparent electrodes 23 formed horizontally on top of the lower substrate 21 and vertically on the bottom of the upper substrate 22 so that the electrodes of the upper and lower substrates 21 and 22 cross each other, and a liquid crystal layer 24 between the lower and upper substrates; 21 and 22.
Also, rubbed alignment films (not shown) are formed on the surfaces of the lower and upper substrates 21 and 22 facing each other, and the licruid crystal molecules of the liquid crystal layer 24 are aligned along the rubbing direction of the alignment films.
is in addition, lower and upper polarizing plates (not shown) are provided on each outer surface of the lower and upper substrates 21 and 22, and a fluorescent layer 25 coated with red (R), green (G) and blue (B) light emitting phosphors is provided on top of the upper polarizing plate.
The backlight assembly 30 according to the present invention includes a plurality of cold cathode fluorescent tubes 31 arranged at the rear of the LCD panel 20. The cold cathode fluorescent tubes 31 are stacked in oarallel and has a length corresponding to the length of the LCD panel 20. The cold cathode fluorescent tubes 31 are supported by support plates 32 and 33 at the ends thereof and electrically connected to a power supply (not shown).
ohta et al. (U.S. Patent No. 4,678,285) and Breddels et al. (U.S. Patent No. 4,830,469) disclose a light source emitting ultraviolet rays or near-ultraviolet rays having a wavelength of 370nm or less to excite phosphors. However, the ultraviolet rays or the near-ultraviolet rays is easy to change the characteristics of liquid crystal molecules. Thus, the cold cathode fluorescent tubes 31 of the backlight assembly 30 according to the present invention adopts a light source emitting violet rays having a wavelength range of 380 to 420nm, which is disclosed by the present inventors (U.S.
Patent Application No. 08/385,514). That is, the light source includes one phosphor selected from the group consisting of SrP207:Eu, SrMgP207:Eu, Sr,(P04)2:EU, (Sr,Ba)A12S'20.:Eu, Y2Si201:Ce, ZnGaPI:Li,Ti, YTaO,:Nb, CaW04, BaFX:Eu (wherein X is halogen), (Sr,Ca)0.2B203:Eu, SrAll2014:Eu and Y2S'O,:Ce. The is violet rays emitted from the light source effectively illuminate the phosphors of the fluorescent layer 25 without changing the characteristics of the liquid crystal molecules.
Preferably, the phosphors disclosed in the above U.S.
Patents and U.S. Patent Application No. 08,385,514 are used as the phosphors of the fluorescent layer 25. That is, the fluorescent layer consists of a blue light emitting phosphor, a green light emitting phosphor, and a red light emitting phosphor, wherein the blue light emitting phosphor is at least one compound selected from the group consisting of SrI, (P01) 6C112: EU2+' (Sr, Ca,) 10 (P04) 6C12: EU2' Sr3M9S'P,: EU2,' Ba3M9S'20,: EU2,, ZnS:Ag,Cl, ZnS:Ag,Al, ZnS:Ag, ZnO:Ag and ZnS:Ag,Ga, the green light emitting phosphor is at least one compound selected from the group consisting of SrAI104:EU2, 6 SrGa2S4: EU2, Y3A15012: Ce 3' ZnS:Cu, ZnS:Cu,Al, CdS:Cu,Al and ZnS:Cu,Au, Al, and the red light emitting phosphor is at least one compound selected from the group consisting of Ge02 n 6MgO.AS205:Mn, 3.5MgO.O.5MgF2:Mn, Sry2SI:Eu, Sry2S4:Mn, KSEU (W04) 41 Y202S: Eu and Y203: Eu.
Also, in order to prevent light of wavelengths above 42onm from being illuminated, the cold cathode fluorescent tubes 31 are coated with a film of at least one selected from the group consisting of cobalt (Co), nickel (Ni) and iron (Fe).
According to the backlight assembly of the present invention, the cold cathode fluorescent tubes 31 may be illuminated consecutively in the same way that television screens are scanned. That is, the uppermost fluorescent tube is 31. is illuminated, then, after a predetermined time, the uppermost fluorescent tube 31, is turned off. As the uppermost fluorescent tube 31, is turned off, the next fluorescent tube 312 is illuminated. (Here, even though the fluorescent tube 311 is turned off, a diminishing illumination still glows.) Then, as the fluorescent tube 312 is turned off, a fluorescent tube 313 under the fluorescent tube 312 'S illuminated. This is repeated for all the fluorescent tubes to a fluorescent tube 31,. in this manner, all of the cold cathode fluorescent tubes 31 are illuminated. Here, preferably, an illuminating period of each of. the fluorescent tubes 31 is controlled so that a viewer perceives the consecutively illuminated image as a continuous image due zo the afterimage effect of the eyes.
Thus, the consecutive line illumination of the cold cathode 7 fluorescent tubes 31 has the same effect as a surface illumination of the entire fluorescent layer 25.
The light illuminated from the consecutive illuminating backlight assembly is polarized by the lower polarizing plate (not shown) and then passes through the lower substrate 21 to reach the liquid crystal layer 24. When a voltage is applied to the transparent electrodes 23 from a cower source which is independent of the power source of the backlight assembly, the liquid crystal molecules which are usually arranged in spiral form line up with respect to the transparent electrodes 23. Thus, light passes through the liquid crystal layer 24, the upper substrate 22 and the upper polarizing plate (not shown) in sequence and then reaches the fluorescent layer 25. The light arriving at the fluorescent layer 25 excites the is designated phosphors of the fluorescent layer 25 to be L1luminated, thereby providing a color image.
FIG. 3 shows the consecutive illuminating backlight assembly according to another preferred embodiment of the present invention. As shown in FIG. 3, a plurality of support plates 42 are stacked in parallel and each support plate is provided with a plurality of light emitting diodes 41. The light emitting diodes 41 are made of GaN-semiconductor to easily control the wavelength of the light emitted therefrom.
The plurality of light emitting diodes 41 are arranged in lines and each line cf: light emitting diodes 41 is supported by one of the.supporu elates 42. The light emitting diodes 41 of one line are simultaneously illuminated or turned off and the light emitting diodes 41 are consecutively illuminated or 3 turned off by line, thereby creating a continuous image. The violet rays emitted from the light emitting diodes 41 pass through a LCD panel 50 to excite phosphors 51 of a fluorescent layer.
The consecutive line illumination of the present invention provides uniform illumination of light over the LCD panel as well as a surface illuminating effect of the entire fluorescent layer, thereby lowering power consumption.
9

Claims (8)

What is claimed is:
1. A consecutive illuminating backlight assembly for a liquid crystal display,LCD) employing a fluorescent layer comprising:
a plurality of cold cathode fluorescent tubes stacked in parallel and having a length corresponding to the length of a LCD panel; and support plates for supporting said cold cathode fluorescent tubes at both ends thereof and providing electrical connections to said cold cathode fluorescent tubes at both ends thereof, wherein said cold cathode fluorescent tubes are illuminated consecutively to form a continuous image on a screen, and emit violet rays having a wavelength of 380-420= is to excite phosphors of said fluorescent layer.
2. A consecutive illuminating backlight assembly as claimed in claim 1, wherein said fluorescent layer consists of a blue light emitting phosphor, a green light emitting phosphor, and a red light emitting phosphor, wherein said blue light emitting phosphor is at least one compound selected from the group consisting of SrIO (P04) 6C112: EU2, (Sr,: EU2,' Sr EU2' 9Ca,1) 1. (P04) 6C12 3M9S'2013 Ba3M9S'20.: EU2,, ZnS:Ag,Cl, ZnS:Ag,Al, ZnS:Ag, ZnO:Ag and ZnS:Ag,Ga, said green light emitting phosphor is at least one compound selected from the group consisting of SrAlPI:EU2,, SrGa2S4: EU2,, Y,Al.012:Ce3', ZnS:Cu, ZnS:Cu,Al, CdS:Cu,Al and ZnS:Cu,Au,Al, and said red light emitting phosphor is at least one compound selected from the group consisting of MgO-AS20.:Mn, 3.5MgO.O.5MgF2-Ge02:Mn, Sry2S4:Eu, Sry2S4:Mn, K,Eu (W04) 41 Y202S: Eu and Y20.1: Eu.
3. A consecutive illuminating backlight assembly as claimed in claim 1, wherein said cold cathode fluorescent tube comprises at least one phosphor selected from the group consisting of SrP207:EU, SrMgP207:EU, Sr,(P04)2:Eu, (Sr,Ba)A12S'20,:Eu, Y2S'207:Ce, ZnGaPI:Li,Ti, YTa04:Nb, CaW04, BaFX:Eu (wherein X is halogen), (Sr,Ca)0.2B203:Eu, SrAll20ll:Eu and Y2S'o.: Ce.
4. A consecutive illuminating backlight assembly as claimed in claim 3, wherein said cold cathode fluorescent tube is coated with at least one element selected from the group consisting of Co, Ni and Fe.
5. A consecutive illuminating backlight assembly for an is LCD employing a fluorescent layer comprising:
a plurality of light emitting diodes as a light source; and a plurality of support plates stacked in parallel so that each support plate supports a line of said light emitting diodes, wherein said light emitting diodes are consecutively illuminated by lines to form a continuous image on a screen, and emits violet rays having a wavelength of 380nm to 420= to excite phosphors of said fluorescent layer.
6. A consecutive illuminating backlight assembly as claimed in claim 5, wherein said fluorescent layer consists of a blue light emitting phosphor, a green light emitting phosphor, and a red light emitting phosphor, wherein said blue light emitting phosphor is at least one compound selected from the group consisting of SrI, (P04) 6C112: EU2, (S r a,. 1) 10 (PO: EU2., Sr EU2, 1) 6C12 3M9S'2OS Ba,M9S'20.: EU2,' ZnS:Aq,Cl, ZnS:Ag,Al, ZnS:Ag, ZnO:Ag and ZnS:Ag,Ga, said green light emitting phosphcr is at least one compound selected from the group consisting of SrAl204:EU2+, SrGa2S4: Eu2', Y3A1,012:Ce', ZnS:Cu, ZnS:Cu,Al, CdS:Cu,Al and ZnS:Cu,Au,Al, and said red light emitting phosphor is at least one compound selected from the group consisting of 6MgO.AS20.:Mn, 3.5MgO-0.5MgF2.Ge02:Mn, Sry2S4:EU, SrY,S4:Mn, K.Eu(W04) 41 Y202S:Eu, and Y203:EU.
7. A consecutive illuminating backlight assembly as claimed in claim 5, wherein said light emitting diode is formed of GaN-semiconductor.
8. A consecutive illuminating backlight assembly as claimed in claim 1 substantially as herein described with reference to the accompanying drawings.
12
GB9705790A 1996-03-20 1997-03-20 Backlight for a liquid crystal display Withdrawn GB2311643A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1019960007561A KR100200663B1 (en) 1996-03-20 1996-03-20 Back-light device for lcd

Publications (2)

Publication Number Publication Date
GB9705790D0 GB9705790D0 (en) 1997-05-07
GB2311643A true GB2311643A (en) 1997-10-01

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GB9705790A Withdrawn GB2311643A (en) 1996-03-20 1997-03-20 Backlight for a liquid crystal display

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JP (1) JPH09258227A (en)
KR (1) KR100200663B1 (en)
DE (1) DE19711669A1 (en)
GB (1) GB2311643A (en)
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EP1521235A2 (en) * 2003-10-03 2005-04-06 LumiLeds Lighting U.S., LLC Liquid crystal display backlight with a two-dimensional array of light emitting diodes
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CN100380195C (en) * 2003-05-15 2008-04-09 友达光电股份有限公司 Liquid crystal display modular group
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Publication number Priority date Publication date Assignee Title
EP1282171A2 (en) * 2001-07-31 2003-02-05 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH LED-based planar light-source
EP1282171A3 (en) * 2001-07-31 2010-06-09 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH LED-based planar light-source
EP1521235A2 (en) * 2003-10-03 2005-04-06 LumiLeds Lighting U.S., LLC Liquid crystal display backlight with a two-dimensional array of light emitting diodes
EP1521235A3 (en) * 2003-10-03 2005-06-08 LumiLeds Lighting U.S., LLC Liquid crystal display backlight with a two-dimensional array of light emitting diodes
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KR970066658A (en) 1997-10-13
GB9705790D0 (en) 1997-05-07
NL1005538C2 (en) 2001-07-05
JPH09258227A (en) 1997-10-03
KR100200663B1 (en) 1999-06-15
DE19711669A1 (en) 1997-11-06
NL1005538A1 (en) 1997-09-23

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