WO2006114750A1 - Systeme de retroeclairage - Google Patents

Systeme de retroeclairage Download PDF

Info

Publication number
WO2006114750A1
WO2006114750A1 PCT/IB2006/051252 IB2006051252W WO2006114750A1 WO 2006114750 A1 WO2006114750 A1 WO 2006114750A1 IB 2006051252 W IB2006051252 W IB 2006051252W WO 2006114750 A1 WO2006114750 A1 WO 2006114750A1
Authority
WO
WIPO (PCT)
Prior art keywords
low
pressure mercury
mercury vapor
vapor discharge
light
Prior art date
Application number
PCT/IB2006/051252
Other languages
English (en)
Inventor
Pieter J. Stobbelaar
Jan P. Dekker
Original Assignee
Koninklijke Philips Electronics N.V.
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 Koninklijke Philips Electronics N.V. filed Critical Koninklijke Philips Electronics N.V.
Publication of WO2006114750A1 publication Critical patent/WO2006114750A1/fr

Links

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
    • G02B6/0066—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
    • G02B6/0068—Arrangements of plural sources, e.g. multi-colour light sources
    • 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
    • G02B6/007—Incandescent lamp or gas discharge lamp
    • G02B6/0071—Incandescent lamp or gas discharge lamp with elongated shape, e.g. tube
    • 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]

Definitions

  • the invention relates to a backlighting system for illuminating a display device comprising a first low-pressure mercury vapor discharge lamp, a second low-pressure mercury vapor discharge lamp and a light guide.
  • the invention further relates to a display system comprising such a backlighting system.
  • Backlighting units in general comprise low-pressure mercury vapor discharge lamps to provide uniform illumination to a display device.
  • the low-pressure mercury vapor discharge lamps comprise a discharge vessel in which an inner wall of the discharge vessel is provided with a luminescent layer comprising a luminescent material.
  • the luminescent material mostly comprises a mix of different phosphors. Generally a mix of three different phosphors is used in which each one of the different phosphors contributes to the spectrum of light emitted by the low-pressure mercury vapor discharge lamp and thus the spectrum of light emitted by the backlighting system.
  • the color gamut which can be displayed by the LCD is determined by a combination of the spectrum of light emitted by the low-pressure mercury vapor discharge lamp and the transmission characteristics of the color filters used in the LCD.
  • a display system having a backlighting system which combines currently commercially available phosphors in the low-pressure mercury vapor discharge lamp with an LCD comprising currently commercially available color filters typically can display a color gamut which does not fully cover the color gamut defined in, for example, the well-known European Broadcasting Union (further also referred to as EBU) color standard.
  • EBU European Broadcasting Union
  • the known color display comprises a plurality of picture elements.
  • the backlighting unit comprises two selectable light sources having different predetermined radiance spectra.
  • the known color display device further comprises a controller which is arranged to select alternatively one of the selectable light sources during a first and a second period, respectively, and which provides a portion of the picture elements with image information corresponding to the primary color obtainable with the selected light source of the backlighting unit.
  • the color display device is a direct view LCD device provided with a fluorescent backlight.
  • the backlight is provided with two or more sets of fluorescent lamps, with each set of fluorescent lamps containing lamp types having their own, tuned mix of phosphors to produce the proper spectrum. The sets of fluorescent lamps are flashed in sequence.
  • the object is achieved with a backlighting system for spectrum sequentially illuminating a display device, the backlighting system comprising: a first low-pressure mercury vapor discharge lamp having a first discharge vessel, a wall of the first discharge vessel being provided with a first luminescent layer comprising at least a first luminescent material for providing a first spectrum of light, the first low-pressure mercury vapor discharge lamp being arranged for direct incidence of light on the display device, a second low-pressure mercury vapor discharge lamp having a second discharge vessel, a wall of the second discharge vessel being provided with a second luminescent layer comprising at least a second luminescent material for providing a second spectrum of light, the second spectrum being distinct from the first spectrum, the second low- pressure mercury vapor discharge lamp being arranged for edge lighting toreduce absorption of light from the first low-pressure mercury vapor discharge lamp by the luminescent material of the second low-pressure mercury vapor discharge lamp or to reduce absorption of light from the second low-pressure mercury vapor discharge lamp
  • the first low-pressure mercury vapor discharge lamp for direct incidence of light on to the display device and the second low-pressure mercury vapor discharge lamp for edge illumination, direct incidence of light emitted by the first low- pressure mercury vapor discharge lamp on to the second low-pressure mercury vapor discharge lamp and direct incidence of light emitted by the second low-pressure mercury vapor discharge lamp on to the first low-pressure mercury vapor discharge lamp is reduced.
  • the inventors have realized that the efficiency in a known backlighting system for spectrum sequential illumination comprising, for example, two types of low-pressure mercury vapor discharge lamps is limited.
  • the different types of low-pressure mercury vapor discharge lamps generally comprise a different mix of luminescent material and therefore each produce light having a different radiance spectrum.
  • the limited efficiency in the known backlighting systems is typically due to absorption of light from one type of low-pressure mercury vapor discharge lamp by luminescent material of another type of low-pressure mercury vapor discharge lamp.
  • the first low-pressure mercury vapor discharge lamp is arranged for direct incidence of light on to the display device and the second low-pressure mercury vapor discharge lamp is arranged for edge illumination.
  • the proposed arrangement of the first and second low-pressure mercury vapor discharge lamps reduces absorption of a major part of the light from one type of the low-pressure mercury vapor discharge lamps by luminescent material of the other type of low-pressure mercury vapor discharge lamp and thus improves the efficiency of the backlighting system.
  • the backlighting system further comprises light blocking means for blocking direct incidence of light from the first low- pressure mercury vapor discharge lamp on to the second low-pressure mercury vapor discharge lamp, or for blocking direct incidence of light from the second low-pressure mercury vapor discharge lamp on to the first low-pressure mercury vapor discharge lamp.
  • the blocking means enable the first and second low- pressure mercury vapor discharge lamps to be arranged substantially in one plane, for example, on the same printed circuit board (further also referred to as PCB) inside the backlighting system.
  • the light blocking means are constituted by a reflector surrounding the second low-pressure mercury vapor discharge lamp.
  • the backlighting system comprises a plurality of first low-pressure mercury vapor discharge lamps and at least one second low-pressure mercury vapor discharge lamp, the number of first low-pressure mercury vapor discharge lamps being at least three and preferably four times larger than the number of second low-pressure mercury vapor discharge lamps, .
  • An advantage of this embodiment is that the plurality of first low-pressure mercury vapor discharge lamps, for example, are optimized to provide optimal white light with high efficiency and efficacy and the second low-pressure mercury vapor discharge lamp, for example, comprises luminescent material for improving the color saturation of the backlighting system.
  • the inventors have realized that the color gamut of a color display improves by adding a relatively low intensity of saturated colors to the system. The decoupling of light sources into a light source for optimal white light and a light source for color saturation results in a backlighting system with both good color saturation and high brightness white point, while good efficiency is maintained.
  • the first luminescent layer comprises europium-activated barium magnesium aluminate (further also referred to as BAM), cerium- terbium coactivated lanthanum phosphate (further also referred to as LAP) and europium- activated yttrium oxide (further also referred to as YOX) and the second luminescent layer comprises magnesium germanate (further also referred to as MGM).
  • BAM europium-activated barium magnesium aluminate
  • LAP cerium- terbium coactivated lanthanum phosphate
  • YOX europium- activated yttrium oxide
  • MGM magnesium germanate
  • the first low-pressure mercury vapor discharge lamp comprising luminescent materials BAM, LAP and YOX provides light having a high brightness white point
  • the second low-pressure mercury vapor discharge lamp comprising MGM boosts red saturation brightness, increasing the color gamut of the color display device.
  • the luminescent material MGM absorbs, besides ultraviolet light from a gas discharge within the discharge vessel of the low-pressure mercury vapor discharge lamp, also blue light emitted by the luminescent material BAM and converts the absorbed light into deep red light.
  • the absorption of blue light from the luminescent material BAM by the luminescent material MGM reduces the blue efficiency of the known backlighting system.
  • the first low- pressure mercury vapor discharge lamp is arranged for direct incidence of light on to the display device and the second low-pressure mercury vapor discharge lamp is arranged for edge lighting. Due to this arrangement of the first and second low-pressure mercury vapor discharge lamp, the luminescent material MGM (in the second low-pressure mercury vapor discharge lamp) is substantially shielded from the light emitted by the luminescent material BAM (in the first low-pressure mercury vapor discharge lamp), reducing the absorption of the blue light by the luminescent material MGM and increasing the efficiency of the backlighting system.
  • the second luminescent layer further comprises cerium-activated yttrium aluminium garnet (further also referred to as YAG).
  • YAG cerium-activated yttrium aluminium garnet
  • An advantage when adding YAG as a luminescent material to the second low- pressure mercury vapor discharge lamp is that the second low-pressure mercury vapor discharge lamp enables a perfect red and yellow appearance on the color display device.
  • the luminescent material YAG absorbs blue light emitted by the luminescent material BAM which, in the known backlighting systems, reduces the blue efficiency.
  • both luminescent materials MGM and YAG are substantially shielded from the light emitted by the luminescent material BAM (in the first low-pressure mercury vapor discharge lamp), reducing absorption of the blue light by the luminescent materials MGM and YAG and increasing the efficiency of the backlighting system.
  • the first and second low-pressure mercury vapor discharge lamps are Hot Cathode Fluorescent Lamps (further also referred to as HCFL).
  • HCFL Hot Cathode Fluorescent Lamps
  • the advantage of using HCFL as a low-pressure mercury vapor discharge lamp is that it permitsfast on and off switching of the low-pressure mercury vapor discharge lamp, which is especially beneficial when the low-pressure mercury vapor discharge lamp is used in a scanning or time sequential mode of operation.
  • Fig. 1 shows a backlighting system according to the invention
  • Fig. 2 shows a CIE 1976 chromaticity diagram in a u', v' color space for a standard low-pressure mercury vapor discharge lamp
  • Fig. 3 shows a CIE 1976 chromaticity diagram in a u', v' color space for an embodiment of a first low-pressure mercury vapor discharge lamp (Fig. 3A), for an embodiment of a second low-pressure mercury vapor discharge lamp (Fig. 3B), and for a backlighting system according to the invention which combines the embodiments of the first and second low-pressure mercury vapor discharge lamps in a backlighting system according to Fig.1 (Fig. 3C),
  • Fig. 4 shows a CIE 1976 chromaticity diagram in a u', v' color space for an alternative embodiment of the first low-pressure mercury vapor discharge lamp (Fig. 4A), for an alternative embodiment of the second low-pressure mercury vapor discharge lamp (Fig. 4B), and for a backlighting system according to the invention which combines the alternative embodiments of the first and second low-pressure mercury vapor discharge lamps (Fig. 4C), and
  • Fig. 5 shows a display device.
  • the figures are purely diagrammatic and not drawn to scale. Particularly for clarity, some dimensions are exaggerated strongly. Similar components in the figures are denoted by the same reference numerals as much as possible.
  • Fig. 1 shows a display system 2 having a backlighting system 4, 8 according to the invention and a display device 6.
  • the display device 6 may be, for example, any transmissive display device 6 which requires a backlighting system, for example, an LCD display device.
  • the backlighting system 4, 8 according to the invention comprises a set of first low-pressure mercury vapor discharge lamps 10, a set of second low-pressure mercury vapor discharge lamps 20, and a light guide 30.
  • the set of first low-pressure mercury vapor discharge lamps 10 comprises eight low-pressure mercury vapor discharge lamps which are arranged for direct incidence of light on to the display device 6 (see the dash-dot arrows in Figs. IA and IB).
  • Each one of the first low-pressure mercury vapor discharge lamps 10 comprises a first discharge vessel 12, in which a wall of the first discharge vessel 12 is provided with a first luminescent layer 14 comprising at least a first luminescent material.
  • the set of second low-pressure mercury vapor discharge lamps 20 comprises two low- pressure mercury vapor discharge lamps which are arranged for edge illumination (see the dashed arrows).
  • Each one of the second low-pressure mercury vapor discharge lamps 20 comprises a second discharge vessel 22, in which a wall of the second discharge vessel 22 is provided with a second luminescent layer 24 comprising at least a second luminescent material.
  • the light guide 30 is arranged between the set of first low-pressure mercury vapor discharge lamps and the display device 6 and comprises two light entrance windows 32 for admitting light from each of the second low-pressure mercury vapor discharge lamps 20 into the light guide 30.
  • the light from the second low-pressure mercury vapor discharge lamps is substantially confined inside the light guide 30, for example, via total internal reflection.
  • the light guide 30 further comprises a light exit window 34 facing the display device 6and having, for example, light out-coupling elements 36 for coupling out the light confined inside the light guide 30 toward the display device 6.
  • Each one of the first low-pressure mercury vapor discharge lamps 10 comprises at least a first luminescent material for emitting a first spectrum of light toward the display device 6.
  • Each one of the second low-pressure mercury vapor discharge lamps 20 comprises at least a second luminescent material for emitting a second spectrum of light, via the light guide 30, toward the display device 6.
  • Luminescent materials in low-pressure mercury vapor discharge lamps 10, 20 typically convert ultraviolet light emitted by a mercury vapor discharge inside the discharge vessel 12, 22 of the low-pressure mercury vapor discharge lamps 10, 20 into visible light.
  • the first spectrum and the second spectrum are each constituted by a mix of luminescent materials selected such that when the set of first low-pressure mercury vapor discharge lamps 10 and the set of second low-pressure mercury vapor discharge lamps 20 are sequentially switched by a controller (not shown), the display device 6 is able to generate a color gamut having a required white-point.
  • a first low-pressure mercury vapor discharge lamp 10 is, for example, a commercially available low-pressure mercury vapor discharge lamp comprising europium-activated barium magnesium aluminate (BAM), cerium-terbium coactivated lanthanum phosphate (LAP) and europium-activated yttrium oxide (YOX) in weight percentages of 34%, 40% and 26%, respectively, hereinafter also referred to as reference B/L/Y lamp.
  • BAM europium-activated barium magnesium aluminate
  • LAP cerium-terbium coactivated lanthanum phosphate
  • YOX europium-activated yttrium oxide
  • the combination of the luminance materials BAM, LAP and YOX is chosen such that the reference B/L/Y lamp produces relatively high brightness with relatively high efficiency and efficacy.
  • the color saturation of the reference B/L/Y lamp is limited, especially with respect to red and blue emission.
  • a second low-pressure mercury vapor discharge lamp 20 may be added comprising the suitable red emitting luminance material, for example, magnesium germanate (MGM).
  • MGM magnesium germanate
  • a drawback of the luminance material MGM is that it absorbs, besides ultraviolet light from a gas discharge within the discharge vessel 22, also blue light, for example, emitted by the luminescent material BAM of the first low-pressure mercury vapor discharge lamp 10.
  • Arranging a first low-pressure mercury vapor discharge lamp 10 comprising the luminance material BAM next to a second low-pressure mercury vapor discharge lamp 20 comprising the luminance material MGM in a backlighting system would result in a substantial loss of blue emission in the backlighting system, reducing the color saturation of the backlighting system.
  • first low-pressure mercury vapor discharge lamps 10 for direct incidence of light on to the display device 6, and of the second low- pressure mercury vapor discharge lamps 20 for edge illumination Due to the arrangement of the first low-pressure mercury vapor discharge lamps 10 for direct incidence of light on to the display device 6, and of the second low- pressure mercury vapor discharge lamps 20 for edge illumination, direct incidence of light emitted by the first low-pressure mercury vapor discharge lamp 10 on to the second low- pressure mercury vapor discharge lamp 20, and vice versa, is reduced, which reduces absorption of light from the first low-pressure mercury vapor discharge lamp 10 by the luminescent material of the second low-pressure mercury vapor discharge lamp 20, and vice versa.
  • the spectrum of light emitted by the set of first low-pressure mercury vapor discharge lamps 10 illuminates the display device 6 via the light guide 30, while the spectrum of light emitted by the set of second low-pressure mercury vapor discharge lamps 20 is confined inside the light guide 30 and illuminates the display device 6 via the light exit window 34.
  • Fig. IA shows a cross-sectional view of the display system 2 having a backlighting system 4 according to the invention and a display device 6.
  • the backlighting system 4 comprises a set of first low-pressure mercury vapor discharge lamps 10, a light guide 30 and a set of second low-pressure mercury vapor discharge lamps 20.
  • the set of first low-pressure mercury vapor discharge lamps 10 are arranged for direct incidence of light on to the display device 6 via the light guide 30 (see the dash-dot arrows in Fig. IA).
  • the set of second low-pressure mercury vapor discharge lamps 20 are arranged for edge lighting. In the embodiment shown in Fig. IA, each one of the set of second low-pressure mercury vapor discharge lamps 20 is arranged at an entrance window 32 of the light guide 30.
  • the light exit window 34 comprises light out-coupling elements 36 which, for example, are constituted byscratches. Other embodiments of light out-coupling elements 36, for example, optical elements like lenses, diffusers, prisms or deformation, may be used without departing from the scope of the invention.
  • the backlighting system 4 further comprises a reflector 42 which ensures that substantially all of the light emitted by the second low- pressure mercury vapor discharge lamp 20 is coupled into the light guide 30.
  • the reflector 42 is further arranged for shielding against direct incidence of light emitted by the set of first low-pressure mercury vapor discharge lamps 10 on to the second low-pressure mercury vapor discharge lamp 20, and vice versa.
  • Fig. IB shows a cross-sectional view of the display system 2 having a backlighting system 8 according to the invention and a display device 6.
  • the backlighting system 8 also comprises a set of first low-pressure mercury vapor discharge lamps 10, a light guide 30 and a set of second low-pressure mercury vapor discharge lamps 20, identical to the embodiment shown in Fig. IA.
  • the set of first low-pressure mercury vapor discharge lamps 10 and the set of second low-pressure mercury vapor discharge lamps 20 are substantially arranged in a single plane.
  • An advantage of this arrangement is that, for example, all low-pressure mercury vapor discharge lamps 10, 20 in the backlighting system 8 can be connected to a single printed circuit board.
  • the backlighting system 8 iurther comprises light blocking elements 40 for blocking direct incidence of light from the first low-pressure mercury vapor discharge lamp 10 on to the second low-pressure mercury vapor discharge lamp 20, or vice versa.
  • the light blocking element 40 is,for example, a foil applied between first low-pressure mercury vapor discharge lamps 10 and the second low-pressure mercury vapor discharge lamps 20, or, for example, a mechanical construction for mounting the light guide 30 into the backlighting system 8.
  • Fig. 1C shows a simplified plan view of the display system 2 having a display device 6 and a backlighting system 4.
  • the backlighting system 4, 8 comprises eight first low-pressure mercury vapor discharge lamps 10 and two second low-pressure mercury vapor discharge lamps 20. This ratio between the number of first low-pressure mercury vapor discharge lamps 10 and the number of second low-pressure mercury vapor discharge lamps 20, together with a mix of luminescent materials in the low-pressure mercury vapor discharge lamps 10, 20 as shown in Figs. 3 and 4, determines the color gamut and white-point of the display system 2.
  • the white-point and/or color gamut of the display system 2 varies.
  • Fig. 2 shows a CIE 1976 chromaticity diagram in a u', v' color space comparing an EBU-standard 52 with a reference B/L/Y color gamut 54.
  • the EBU-standard 52 is a color gamut defined by the European Broadcasting Union related to phosphors typically used in television systems.
  • the reference B/L/Y color gamut 54 results from combining the emission spectrum of the reference B/L/Y lamp with transmission spectra of a typical set of color filters used in an LCD display device.
  • the upper left corner of the EBU-standard 52 represents green
  • the upper right corner of the EBU- standard 52 represents red
  • the lower corner of the EBU-standard represents blue.
  • the reference B/L/Y lamp combines the luminance materials BAM, LAP and YOX in weight percentages of 34%, 40% and 26%, respectively, to produce light having relatively high brightness with relatively high efficiency and efficacy.
  • the color saturation of the reference B/L/Y lamp is limited with respect to the standard defined by the EBU, which can be seen from a comparison between the reference B/L/Y color gamut 54 and the EBU-standard 52.
  • red upper right corner of the EBU-standard 52
  • blue lower corner of the EBU-standard 52
  • the reference B/L/Y color gamut 54 does not cover the EBU-standard 52.
  • a backlighting system comprising a set of reference B/L/Y lamps will not be able to display fully saturated red and blue from these video images.
  • Fig.2 also indicates a spectral color perception line 50 indicating the spectral colors which can be perceived by the human eye.
  • a comparison is made between the color gamut of low-pressure mercury vapor discharge lamps having different mixtures of luminescent materials and the EBU-standard 52.
  • the color gamut of the low- pressure mercury vapor discharge lamps may also be compared with other color gamut standards, such as the color gamut standard of the National Television Standards Committee (NTSC) or the color gamut standard of Systeme Electronic Pour Couleur Avec Memoire (SECAM) without departing from the scope of the invention.
  • Fig. 3 shows a CIE 1976 chromaticity diagram in a u', v' color space for an embodiment of the backlighting system 4, 8 according to the invention.
  • a first B/L/Y color gamut 56 is shown of a first embodiment of the first low-pressure mercury vapor discharge lamp 10 in a backlighting system 4, 8 according to the invention.
  • the first embodiment of the first low-pressure mercury vapor discharge lamp 10 is further also referred to as first B/L/Y lamp 10.
  • the first B/L/Y color gamut 56 results from a combination of the luminance materials BAM, LAP and YOX in the first B/L/Y lamp 10 having weight percentages of 45%, 50% and 5%, respectively.
  • the first B/L/Y lamp 10 comprises a reduced amount of the luminance material YOX compared to the reference B/L/Y lamp.
  • the first B/L/Y lamp 10 still produces light having relatively high brightness with even improved efficiency with respect to the reference B/L/Y lamp.
  • the reduction of the luminance material YOX also results in reduced color saturation with respect to the reference B/L/Y lamp.
  • the reduction of the luminance material YOX with respect to the reference B/L/Y lamp is compensated for by adding, for example, an MGM- lamp 20, being an embodiment of the second low-pressure mercury vapor discharge lamp 20 in the backlighting system 4, 8 according to the invention.
  • the MGM-lamp 20 comprises, as the luminescent material, magnesium germanate (MGM) for boosting red saturation brightness in the backlighting system 4, 8.
  • Fig.3B shows a MGM color gamut 58 of the MGM-lamp 20.
  • the backlighting system emits light having improved color saturation, while substantially maintaining a similar white point and efficiency compared to a backlighting system having ten reference B/L/Y lamps.
  • the combined color gamut 60 is shown in Fig.3C.
  • the luminescent material MGM absorbs, besides ultraviolet light from a gas discharge within the discharge vessel 22, also blue light, for example, emitted by the luminescent material BAM and converts the absorbed light into deep red light.
  • the MGM- lamp 20 would simply be arranged next to the first B/L/Y lamps 10 the absorption of blue light by the luminescent material MGM would cause a significant reduction of the blue emission of the backlighting system.
  • the luminescent material MGM in the second low-pressure mercury vapor discharge lamp 20
  • the luminescent material BAM in the first low-pressure mercury vapor discharge lamp 10
  • Fig. 4 shows a CIE 1976 chromaticity diagram in a u', v' color space for an alternative embodiment of the backlighting system 4, 8 according to the invention.
  • a second B/L/Y color gamut 62 is shown of a second B/L/Y lamp 10 being a further embodiment of the first low-pressure mercury vapor discharge lamp 10 in the backlighting system 4, 8 according to the invention.
  • the second B/L/Y color gamut 62 results from a combination of the luminance materials BAM, LAP and YOX in the second B/L/Y lamp 10 having weight percentages of 55%, 35% and 10%, respectively.
  • the different mix of the luminance materials BAM, LAP and YOX in the second B/L/Y lamp 10 results in a different color saturation with respect to the reference B/L/Y lamp.
  • a MGM/Y AG- lamp 20 is added as a second embodiment of the second low-pressure mercury vapor discharge lamp 20.
  • the MGM/Y AG- lamp 20 comprises the luminescent materials magnesium germanate (MGM) and cerium- activated yttrium aluminium garnet (YAG) in weight percentages of 60% and 40%, respectively.
  • Fig.4B shows an MGM/YAG color gamut 64 of the MGM/YAG-lamp 20.
  • the backlighting system When combining eight second B/L/Y lamps 10 with two MGM/YAG- lamps 20 in a backlighting system, the backlighting system emits light having an improved color saturation, while maintaining a substantially similar white point and efficiency compared to a backlighting system having ten reference B/L/Y lamps.
  • the combined color gamut 66 is shown in Fig.4C.
  • a drawback when using the luminescent material MGM and the luminescent material YAG is that these luminescent materials both absorb, besides ultraviolet light from a gas discharge within the discharge vessel 22, also blue light, for example, emitted by the luminescent material BAM and convert the absorbed light into deep red and yellow light, respectively.
  • the MGM/Y AG- lamp 20 would simply be arranged next to the second B/L/Y lamps 10 the absorption of blue light by the luminescent materials MGM and YAG would cause a significant reduction of the blue emission of the backlighting system.
  • the luminescent materials MGM and YAG in the second low-pressure mercury vapor discharge lamp 20
  • the luminescent material BAM in the first low-pressure mercury vapor discharge lamp 10
  • Fig. 5 shows a display system 70, for example, a Liquid Crystal Display system 70 comprising the backlighting system 4, 8 according to the invention.
  • any reference signs placed between parentheses shall not be construed as limiting the claim.
  • Use of the verb "comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim.
  • the article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements.
  • several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Planar Illumination Modules (AREA)

Abstract

L'invention concerne un système de rétroéclairage (4, 8) destiné à l'éclairage séquentiel spectral d'un dispositif d'affichage (6). Ce système de rétroéclairage comprend une première lampe à décharge de vapeur de mercure basse pression (10) renfermant au moins une première matière luminescente émettant un premier spectre de lumière, une seconde lampe à décharge de vapeur de mercure basse pression (20) renfermant au moins une seconde matière luminescente émettant un second spectre de lumière, ainsi qu'un guide de lumière (30) comportant une fenêtre d'entrée (32) destinée à laisser entrer la lumière en provenance de la seconde lampe à décharge de vapeur de mercure basse pression (20) dans le guide de lumière (30), et possédant une fenêtre de sortie de lumière (34) faisant face au dispositif d'affichage (6). La première lampe à décharge de vapeur de mercure basse pression (10) est conçue pour permettre à la lumière d'être incidente sur le dispositif d'affichage (6), la seconde lampe à décharge de vapeur de mercure basse pression (20) est destinée à un éclairage périphérique, et le guide de lumière (30) est disposé entre la première lampe à décharge de vapeur de mercure basse pression (10) et le dispositif d'affichage (6). La disposition desdites première et seconde lampes à décharge de vapeur basse pression (10, 20) selon l'invention permet de réduire l'absorption de la lumière en provenance de la première lampe à décharge de vapeur de mercure basse pression (10) par la matière luminescente de la seconde lampe à décharge de vapeur de mercure basse pression (20), et vice versa. Cela permet d'augmenter l'efficacité du système de rétroéclairage (4, 8).
PCT/IB2006/051252 2005-04-27 2006-04-21 Systeme de retroeclairage WO2006114750A1 (fr)

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
EP05103445.2 2005-04-27
EP05103444.5 2005-04-27
EP05103456 2005-04-27
EP05103445 2005-04-27
EP05103456.9 2005-04-27
EP05103444 2005-04-27
EP05109466 2005-10-12
EP05109466.2 2005-10-12

Publications (1)

Publication Number Publication Date
WO2006114750A1 true WO2006114750A1 (fr) 2006-11-02

Family

ID=36889130

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2006/051252 WO2006114750A1 (fr) 2005-04-27 2006-04-21 Systeme de retroeclairage

Country Status (2)

Country Link
TW (1) TW200705509A (fr)
WO (1) WO2006114750A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006056150A1 (de) * 2006-11-28 2008-05-29 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Vorrichtung zur Abstrahlung elektromagnetischer Strahlung und Anzeigevorrichtung
WO2008132915A1 (fr) * 2007-04-18 2008-11-06 Sharp Kabushiki Kaisha Dispositif de rétroéclairage et dispositif d'affichage à cristaux liquides
WO2011124599A1 (fr) * 2010-04-09 2011-10-13 Zumtobel Lighting Gmbh Arrangement d'émission de lumière comprenant plusieurs sources de lumière et un élément diffuseur de lumière transparent
DE102012203791A1 (de) * 2012-03-12 2013-09-12 Zumtobel Lighting Gmbh LED-Modul
DE102012020985A1 (de) * 2012-10-25 2014-04-30 Bartenbach Holding Gmbh Beleuchtungsvorrichtung

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0896897A2 (fr) * 1997-08-14 1999-02-17 Mannesmann VDO Aktiengesellschaft Unité d'affichage pour la fixation dans une automobile
US6608614B1 (en) * 2000-06-22 2003-08-19 Rockwell Collins, Inc. Led-based LCD backlight with extended color space
WO2004032523A1 (fr) * 2002-10-01 2004-04-15 Koninklijke Philips Electronics N.V. Dispositif d'affichage couleur
EP1555477A1 (fr) * 2004-01-15 2005-07-20 Zumtobel Staff GmbH Luminaire comprenant des sources lumineuses de différentes couleurs ainsi qu'un guide de lumière plan pour émettre un mélange de lumières

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0896897A2 (fr) * 1997-08-14 1999-02-17 Mannesmann VDO Aktiengesellschaft Unité d'affichage pour la fixation dans une automobile
US6608614B1 (en) * 2000-06-22 2003-08-19 Rockwell Collins, Inc. Led-based LCD backlight with extended color space
WO2004032523A1 (fr) * 2002-10-01 2004-04-15 Koninklijke Philips Electronics N.V. Dispositif d'affichage couleur
EP1555477A1 (fr) * 2004-01-15 2005-07-20 Zumtobel Staff GmbH Luminaire comprenant des sources lumineuses de différentes couleurs ainsi qu'un guide de lumière plan pour émettre un mélange de lumières

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006056150A1 (de) * 2006-11-28 2008-05-29 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Vorrichtung zur Abstrahlung elektromagnetischer Strahlung und Anzeigevorrichtung
US7974506B2 (en) 2006-11-28 2011-07-05 Osram Gesellschaft mit beschränkter Haftung Device for emitting electromagnetic radiation and display device
WO2008132915A1 (fr) * 2007-04-18 2008-11-06 Sharp Kabushiki Kaisha Dispositif de rétroéclairage et dispositif d'affichage à cristaux liquides
WO2011124599A1 (fr) * 2010-04-09 2011-10-13 Zumtobel Lighting Gmbh Arrangement d'émission de lumière comprenant plusieurs sources de lumière et un élément diffuseur de lumière transparent
DE102012203791A1 (de) * 2012-03-12 2013-09-12 Zumtobel Lighting Gmbh LED-Modul
DE102012020985A1 (de) * 2012-10-25 2014-04-30 Bartenbach Holding Gmbh Beleuchtungsvorrichtung

Also Published As

Publication number Publication date
TW200705509A (en) 2007-02-01

Similar Documents

Publication Publication Date Title
US20200011508A1 (en) Method and apparatus to enhance spectral purity of a light source
Harbers et al. LP‐2: high performance LCD backlighting using high intensity red, green and blue light emitting diodes
US7859175B2 (en) Illuminating device, display device and optical film
EP2074475B1 (fr) Système d'éclairage et dispositif d'affichage
US20020006044A1 (en) Assembly of a display device and an illumination system
US7213960B2 (en) Backlight unit assembly using light emitting diode array in liquid crystal display device
US8125152B2 (en) Light source apparatus and liquid crystal display
WO2006114743A2 (fr) Systeme de retroeclairage et systeme d'affichage
CN102812395A (zh) 显示装置和电视接收装置
JPH01114884A (ja) カラー液晶ディスプレイ装置
WO2006114750A1 (fr) Systeme de retroeclairage
WO2011074352A1 (fr) Dispositif d'affichage et récepteur de télévision
TW200621946A (en) Light emitting device with a Eu(III)-activated phosphor and second phosphor
CA2496256A1 (fr) Dispositif d'eclairage
EP2035527A2 (fr) Lampe à décharge de gaz basse pression
WO2006114740A2 (fr) Systeme de retroeclairage a balayage
JP4344526B2 (ja) 液晶表示装置
WO2012124509A1 (fr) Source de lumière, dispositif d'éclairage et dispositif d'affichage
CN108417694B (zh) 发光器件封装件和电子装置
CN100401516C (zh) 白光发光二极管组件的制作方法
WO2006114748A1 (fr) Systeme de retroeclairage
WO2011105145A1 (fr) Dispositif d'affichage et dispositif de réception de télévision
CN100472295C (zh) 光源装置和液晶显示器
WO2011074353A1 (fr) Dispositif d'affichage et récepteur de télévision
TW201915522A (zh) 提升光源的光譜純度之方法與裝置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
NENP Non-entry into the national phase

Ref country code: DE

WWW Wipo information: withdrawn in national office

Country of ref document: DE

NENP Non-entry into the national phase

Ref country code: RU

WWW Wipo information: withdrawn in national office

Country of ref document: RU

122 Ep: pct application non-entry in european phase

Ref document number: 06728011

Country of ref document: EP

Kind code of ref document: A1