CN100472295C - Light source apparatus and liquid crystal display - Google Patents

Light source apparatus and liquid crystal display Download PDF

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Publication number
CN100472295C
CN100472295C CNB2006100994671A CN200610099467A CN100472295C CN 100472295 C CN100472295 C CN 100472295C CN B2006100994671 A CNB2006100994671 A CN B2006100994671A CN 200610099467 A CN200610099467 A CN 200610099467A CN 100472295 C CN100472295 C CN 100472295C
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light
phosphor
emission
supply apparatus
emitting diode
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CN1900789A (en
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藤原贤
新村勉
名取诚
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Sony Corp
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Sony Corp
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Abstract

A liquid crystal display and a light source apparatus capable of improving color reproduction compared to the prior art is disclosed. The light source apparatus includes: a cold cathode fluorescent tube including a B phosphor for blue and a G phosphor for green; and a light emitting diode for red, wherein the G phosphor emits a single-spectrum light with a peak wavelength of 510 to 530 nm, and the light emitting diode emits a single-spectrum light with a peak wavelength of 620 to 650 nm, and does not suffer from declining light intensity.

Description

Light supply apparatus and LCD
Technical field
The present invention relates to launch the light supply apparatus of white light, and the LCD of using this light supply apparatus.
Background technology
In current television receiver (TV), it is standard that NTSC (National Television System Committee (NTSC)) system colors shows.When the color reproduction scope of display during, compare image with the color of original signal and be shown, thereby dynamic range weakens, and has caused the reduction of picture quality with narrower color gamut than NTSC narrow.Recently, in LCD (LCD), attempted the extension color reproduction range as a kind of display.
As the index of color reproduction scope, used so-called NTSC ratio.The NTSC ratio is the ratio of area of the reproduction range of the area of the color gamut that display can reproduce in the xy chromatic diagram and NTSC, and the NTSC ratio is represented by following formula (1):
NTSC ratio (%)=(the leg-of-mutton area S of display)/(leg-of-mutton area S of NTSC N)
(1)
The ad hoc approach that calculates the NTSC ratio will be described below.
The leg-of-mutton area S of representative color reproduction range is determined by following formula (2) to (6) in the chromatic diagram:
Limit RG=[(XR-XG) 2+ (YR-YG) 2] 1/2... (2)
Limit GB=[(XG-XB) 2+ (YG-YB) 2] 1/2... (3)
Limit BR=[(XB-XR) 2+ (YB-YR) 2] 1/2... (4)
Semi-perimeter P=(RG+ limit, limit GB+ limit BR)/2 ... (5)
Area S=[semi-perimeter P] 1/2... (6)
In this case, (XR, YR), (XG, YG) and (XB YB) represents the apex coordinate of red (R) in the triangle of chromatic diagram, green (G) and indigo plant (B) (R chroma point, G chroma point and B chroma point) respectively.Limit RG, GB and BR represent distance between distance, G chroma point and the B chroma point between R chroma point and the G chroma point and the distance between B chroma point and the R chroma point respectively.In the NTSC system, each apex coordinate is as follows, so area S NBe S N≈ 0.157.
XR＝0.67，YR＝0.33
XG＝0.21，YG＝0.71
XB＝0.14，YB＝0.08
On the other hand, represent the vertex of a triangle coordinate (chroma point) of the color reproduction scope of target panel of LCD to determine from spectroscopic data by following mode.Suppose that CIE1931 XYZ color matching functions is x (λ), y (λ) and z (λ), the spectrum of backlight is P (λ), and the spectral-transmission favtor of every kind of color filter of LCD panel is τ (λ), then tristimulus values (X, Y Z) is determined by following formula (7) to (9).In these formula, λ represents optical wavelength.
X＝∫P(λ)x(λ)τ(λ)dλ ...(7)
Y＝∫P(λ)y(λ)τ(λ)dλ ...(8)
Z＝∫P(λ)z(λ)τ(λ)dλ ...(9)
Ratio x, the y of X component, Y component and Z component and z determine from these tristimulus values.
x＝X/(X+Y+Z)
y＝Y/(X+Y+Z)
Then, with every kind of color (x, y) be depicted as each chroma point (XR, YR), (XG, YG) or (XB YB), thereby can obtain to represent the triangle of the color reproduction scope of LCD.Leg-of-mutton area S is determined that by above-mentioned formula (2) to (6) the NTSC ratio is determined by formula (1).
In transmission-type illuminator LCD, up to the present adopt the cold cathode fluorescent tube (CCFL pipe) of emission white light mostly as backlight.In this CCFL pipe, in general, R phosphor, G phosphor and the B phosphor of launching R light, G light and B light respectively are applied to the inner tubal wall surface, and the UV radiation that the inert gas by exciting sealing etc. generates excites every kind of color of light of every kind of phosphor emission.
But, in the LCD of CCFL pipe in adopting correlation technique as light source, exist lower mainly due to its light emitted spectrum thereby NTSC ratio, thereby perhaps there is the problem of color balance in the narrower problem of color gamut.More specifically, color B is no problem, because the color B ultrasonic has been crossed the scope of NTSC system; But in color G and color R, the chromaticity range of color G and R is often narrower, therefore needs to improve to show.
In recent years, for by the extension color scope or improve color balance and improve color reproduction, a kind of technology in conjunction with CCFL pipe and another light source (with reference to Japan without substantive examination public announcement of a patent application No.2004-139876,2005-44756,2004-294984 and 2004-163902) has been proposed.
Summary of the invention
Japan without substantive examination public announcement of a patent application No.2004-139876 and 2005-44756 in, proposed to comprise combination backlight of cold cathode fluorescent tube and light emitting diode (LED).In Japan the structure backlight of the combination that comprises two kinds of light sources has been described in without substantive examination public announcement of a patent application No.2004-139876 and 2005-44756; But, describe spectral range, shape or peak position in detail, and do not illustrate the color reproduction degree that can obtain as the light source of the factor that causes colour gamut (color gamut) expansion or obstruction realization gamut extension.
Japan without substantive examination public announcement of a patent application No.2004-294984 in, disclose a kind of backlightly, it comprises the cold cathode fluorescent tube of color G that emission is selected and B and the LED of emission color R from primary colors R, G and B.Japan without substantive examination public announcement of a patent application No.2004-294984 in, for expanded color gamut, combine and have 630nm or the long LED of above spike, rather than the R phosphor of CCFL pipe, thereby the spike of the light of color R is long to be moved to long wavelength's one side, to obtain the effect of expanded color gamut.But, in the light of color G, comprise and orange corresponding inferior spectrum (spike with 580nm is long) from the emission spectrum of the G phosphor of CCFL pipe, therefore the influence of inferior spectrum still exists, thereby is difficult to realize sufficient gamut extension.Be about 81% based on Japan without the NTSC ratio that substantive examination public announcement of a patent application No.2004-294984 calculates, therefore the space of improvement is still arranged.
Japan without substantive examination public announcement of a patent application No.2004-163902 in, a kind of technology is disclosed, this technology is by improving color reproduction according to the characteristic of improving the color filter of LCD panel as the light emission characteristics of CCFL pipe backlight.According to this technology, the effect of the improvement of color filter is bigger, and as for based on Japan without the NTSC ratio that the description of substantive examination public announcement of a patent application No.2004-163902 calculates, obtained higher value 99.1%.But, in this technology, the passband width of every kind of color filter is narrowed down, to improve colour purity, therefore because the loss that the light shield of color filter causes is bigger, thereby consequently intensity is from 350cd/m 2Drop to 235cd/m 2, promptly descended about 27%.Japan without substantive examination public announcement of a patent application No.2004-163902 in, mentioned light source with the combination that comprises CCFL pipe and LED as method backlight, but do not described in detail, so do not illustrated the structure that can realize gamut extension.
Consider foregoing, need provide and compare the LCD and the light supply apparatus that can improve color reproduction and can not make strength degradation with correlation technique.
According to embodiments of the invention, a kind of light supply apparatus is provided, comprising: cold cathode fluorescent tube, it comprises and is used for blue B phosphor and is used for green G phosphor; And the light emitting diode that is used for redness; Wherein, the emission of G phosphor has 510 to 530nm the long single spectrum light of spike, and the light emitting diode emission has 620 to 650nm the long single spectrum light of spike.
According to embodiments of the invention, a kind of LCD is provided, comprising: light supply apparatus; And liquid crystal display, it comes display image by using from the light of light supply apparatus emission as transillumination light, and wherein light supply apparatus comprises: cold cathode fluorescent tube, it comprises and is used for blue B phosphor and is used for green G phosphor; And be used for red light emitting diode, and the emission of G phosphor has 510 to 530nm the long single spectrum light of spike, and the light emitting diode emission has 620 to 650nm the long single spectrum light of spike.
In light supply apparatus and LCD according to an embodiment of the invention, have only B phosphor and G phosphor to be applied to cold cathode fluorescent tube, and, use emission to have to be positioned at the light emitting diode of the single spectrum at 620 to 650nm peak to replace the R phosphor, therefore eliminated the problem of influence of inferior spectrum of the 595nm of R phosphor in the cold cathode fluorescent tube that occurs in correlation technique.
In above-mentioned light supply apparatus, be sealed in the cold cathode fluorescent tube under the situation as energizing gas in mercury gas, preferably use phosphor that emission has the long single spectrum light of 510 to 520nm spike as the G phosphor.
In addition, be sealed under the situation of cold cathode fluorescent tube as energizing gas at the burst of ultraviolel gas that does not generate the emission line spectrum that is arranged in the wavelength of visible light scope, can use emission to have the phosphor of the long single spectrum light of 510 to 530nm spike as the G phosphor.For this burst of ultraviolel gas, xenon is preferred.In this case, can use emission have 520 to the phosphor of the long single spectrum light of the spikes of 530nm as the G phosphor.
According to another embodiment of the invention, a kind of light supply apparatus of the backlight as liquid crystal display is provided, this liquid crystal display comprises blue color filter, green color filter and the Red lightscreening plate that is used for color display, this light supply apparatus comprises: cold cathode fluorescent tube, and it comprises and is used for blue B phosphor and is used for green G phosphor; Be used for red light emitting diode, its be arranged at cold cathode fluorescent tube at a distance of a distance that makes it possible to take place the blend of colors of light; And diffusion member, its diffusion is from the colorama of cold cathode fluorescent tube emission and the colorama of launching from light emitting diode, thereby owing to the blend of colors of light makes the intensity distributions of white light even, the spike length that wherein is used for the spectral light of red light emitting diode is positioned at outside the transmission peak wavelength scope of green color filter.In this case, the implication of " the spike length that is used for the spectral light of red light emitting diode is positioned at outside the transmission peak wavelength scope of green color filter " is that the transmissivity of the long green color filter of spike is almost nil.
According to another embodiment of the invention, provide a kind of LCD, having comprised: liquid crystal display, it comprises blue color filter, green color filter and Red lightscreening plate, with color display; And as the light supply apparatus of the backlight of liquid crystal display, wherein light supply apparatus comprises: cold cathode fluorescent tube, and it comprises and is used for blue B phosphor and is used for green G phosphor; Be used for red light emitting diode, its be arranged at cold cathode fluorescent tube at a distance of a distance that makes it possible to take place the blend of colors of light; And diffusion member, its diffusion is from the colorama of cold cathode fluorescent tube emission and the colorama of launching from light emitting diode, thereby owing to the blend of colors of light makes the intensity distributions of white light even, the spike length that wherein is used for the spectral light of red light emitting diode is positioned at outside the transmission peak wavelength scope of green color filter.
In light supply apparatus and LCD according to another embodiment of the invention, be used for red light emitting diode and be arranged at the distance that blend of colors can take place with cold cathode fluorescent tube apart, therefore blue light and the green glow from the cold cathode fluorescent tube emission fully mixed with the generation white light with the ruddiness of launching from light emitting diode.White light is had the white light that uniform strength distributes by the diffusion of diffusion member to become.In addition, be set to be positioned at outside the transmission peak wavelength scope of green color filter, can prevent that therefore the part of ruddiness from passing through green color filter from the spectrum peak wavelength of the ruddiness that is used for red light emitting diode emission.
In LCD and light supply apparatus according to an embodiment of the invention, have only B phosphor and G phosphor to be applied to cold cathode fluorescent tube, and used emission to have to be positioned at the light emitting diode of the single spectrum light at 620 to 650nm peak to replace the R phosphor, therefore can be under the situation that does not reduce intensity have improved color reproduction to a greater degree in than correlation technique.
In addition, in LCD and light supply apparatus according to another embodiment of the invention, be positioned at outside the transmission peak wavelength scope of green color filter from the spectrum peak wavelength of the ruddiness of the light emitting diode emission that is used for ruddiness, therefore ruddiness is almost completely stopped by green color filter, thereby can prevent that redness is mixed in the green pixel.As a result, compare, can improve color reproduction with correlation technique.In addition, fully mixed with the ruddiness of launching from light emitting diode from the blue light and the green glow of cold cathode fluorescent tube emission, by the diffusion of diffusion member, therefore can obtain to have the white light that uniform strength distributes, and can prevent then because the deterioration of the color reproduction that Strength Changes causes.
From the following description, of the present invention other will display more fully with further purpose, feature and advantage.
Description of drawings
Fig. 1 is the sectional view according to the major part of the LCD of the embodiment of the invention;
Fig. 2 illustrates comparative example 1 and 2 and the table of the structure of the major part of the light supply apparatus of example 1 to 3;
Fig. 3 is the figure that the color filter characteristic of the spectrum of light supply apparatus of example 1 and LCD panel is shown;
Fig. 4 is the figure that the color filter characteristic of the spectrum of light supply apparatus of example 2 and LCD panel is shown;
Fig. 5 is the figure that the color filter characteristic of the spectrum of light supply apparatus of example 3 and LCD panel is shown;
Fig. 6 is the chromatic diagram of colour gamut that the light supply apparatus of example 1 to 3 is shown;
Fig. 7 is the figure that the emission spectrum of the G look phosphor that uses in the CCFL pipe of example 3 is shown;
Fig. 8 is the figure that the color filter characteristic of the spectrum of light supply apparatus of comparative example 1 and LCD panel is shown;
Fig. 9 is the figure that the color filter characteristic of the spectrum of light supply apparatus of comparative example 2 and LCD panel is shown;
Figure 10 is the chromatic diagram of colour gamut that the light supply apparatus of comparative example 1 and 2 is shown;
Figure 11 is the figure that the emission spectrum of the R look phosphor that uses in the CCFL pipe of comparative example 1 is shown;
Figure 12 is the figure that the emission spectrum of the emission spectrum of the every kind of color phosphor light quality that uses in the CCFL pipe of comparative example 2 and mercury is shown;
Figure 13 is the sectional view according to the major part of the LCD of revising; And
Figure 14 is the integrally-built block diagram according to the LCD of the embodiment of the invention.
Tool is stopped embodiment
Describe preferred embodiment below with reference to the accompanying drawings in detail.
Figure 14 illustrates the block diagram according to the whole LCD that comprises light supply apparatus of the embodiment of the invention.LCD 100 comprises LCD panel 1, optics 2 and light supply apparatus 6, also comprise the LCD control section 132 of the image processing section 131 of carrying out various signal Processing, control LCD panel 1 etc., the video memory 133 of memory image signal, the luminous light source luminaire 134 of control light supply apparatus 6, and the Y driver 138 and the X driver 139 that all drive LCD panel 1.
Fig. 1 illustrates the sectional view of the major part of LCD 100.LCD 100 has so-called direct type backing structure, and optics 2 is arranged to directly below LCD panel 1, and comprises that the light supply apparatus 6 of CCFL pipe 3 and LED4 is arranged to directly below optics 2.Light supply apparatus 6 is supported by shell 5.
LCD panel 1 is a transmissive type liquid crystal panel, and comprises public transparency electrode (not shown) and be arranged in a plurality of pixel electrode (not shown) on the transparency electrode with rectangular in form, and the liquid crystal layer (not shown) is arranged therebetween.In each pixel electrode, formed with color B, G and R in each corresponding color filter layer (not shown).
Optics 2 is to fix by utilizing support component 11 that the peripheral part of optics 2 is pushed on the peripheral part of shell 5, and a spacer (not shown) is arranged therebetween.LCD panel 1 is by utilizing support component 12 that the peripheral part of LCD panel 1 is fixed by being pressed on the support component 11.Reflector plate 7 is arranged on the inside surface of shell 5, and a plurality of CCFL pipe 3 and a plurality of LED 4 are arranged on the reflector plate 7.Owing to arranged reflector plate 7, therefore also can use the light that is transmitted into rear surface one side (side relative) from CCFL pipe 3 with LCD panel 1.
CCFL pipe 3 has the straight tube shape respectively, and is to arrange with the interval that equates.The inner tubal wall surface of CCFL pipe 3 is coated with B phosphor and G phosphor, but not coated with the R phosphor.When gas discharge, excite the energizing gas of UV radiation to be sealed in the CCFL pipe 3, and the UV radiation that generates bump B phosphor and G phosphor to be exciting them, thus emission B coloured light and G coloured light.The characteristic spectral emission of CCFL pipe 3 will be described in detail later.
In general, LED 4 is used to replace the R phosphor on the inner tubal wall surface that is applied to CCFL pipe 3 with emission R coloured light, and LED 4 launches the R coloured light with single spectrum.Shown in Fig. 3 to 5, the wavelength of the emission spectrum peak PR3 of each LED 4 is positioned at outside the transmission peak wavelength scope CFG of green color filter of color filter layer of above-mentioned LCD panel 1.In other words, in the transmissivity of the wavelength location green color filter of peak PRG near zero.Therefore, can prevent that ruddiness from passing through green color filter.Description about this point will provide in the back.
Optics 2 comprises (from the angle order of LCD panel 1) polarization/reflector plate 21, prismatic lens 22, diffusion disk 23 and diffusing panel 24.Diffusion disk 23 and diffusing panel 24 be arranged at light supply apparatus 6 at a distance of diffusion distance fully, thereby and diffuse reflection make light distribution even from the light of light supply apparatus 6.Thereby, can prevent to change owing to the linear intensities that the CCFL pipe 3 as line source causes.Prismatic lens 22 has the function of the directivity of the incident light of regulating diffusion with the intensity of the front surface of raising LCD panel 1.Polarization/reflector plate 21 reflects the S polarized wave of incident light wave in many ways, converts P polarized wave with the axis of homology of LCD panel 1 coupling to S polarized wave that will reflection, thereby can not use incident light lavishly.The entire backlight thickness of structure is to regulate according to spacing between the CCFL pipe 3 and diffusion distance, so that intensity and variation in thickness obtain balance.
A plurality of LED 4 are arranged between the CCFL pipe 3 with the interval that equates, with CCFL pipe 3 at a distance of a distance that makes it possible to take place the blend of colors of light, thereby can prevent to change as the light among the LED4 of pointolite.Part among each LED 4 except that the light radiating portion is capped with reflector plate 7, so that do not stop back to diffusion from CCFL pipe 3.As thermal design, to spend for the working temperature with CCFL pipe 3 maintains 65 to 80, and the working temperature of LED 4 is maintained 65 degree or lower, shell 5 is made by metal (for example AL alloy), to guarantee thermal radiation property.On CCFL pipe 3 shells 5 that are arranged at as radiant panel, air and reflector plate 7 are arranged, so CCFL pipe 3 has bigger thermal resistance therebetween.On the other hand, LED4 is arranged directly on the shell 5, so LED 4 has less thermal resistance.When LED 4 is direct type, to compare with the situation (back will be described) of using light guide plate, easier number by increase LED 4 is regulated brightness.In addition, owing to do not use light guide plate, directly type is suitable for large high-strength TV.
Next, the operation of LCD that below description is had said structure.
As shown in figure 14, be imported in the image processing section 131 by receiving or reproducing the picture signal Vsig that generates.Image processing section 131 realizes the separation between viewdata signals and the synchronizing signal, sends to video memory 133 with the directions X (horizontal scan direction) with the viewdata signal of every sweep trace, and synchronizing signal is sent to LCD control section 132.LCD control section 132 sends the control signal that is used to control the control signal of Y driver 138 and X driver 139 and is used to control light source luminescent equipment 134.
Light source luminescent equipment 134 is by controlling the light emission operation of light supply apparatus 6 from the control signal of LCD control section 132.2 pairs of light that come from light supply apparatus 6 emissions of optics are carried out optical processing (back will be described), so that light is incident upon on the rear surface of LCD panel 1.In LCD panel 1, Y driver 138 is chosen in the basic line by line horizontal scanning line of going up display image, and X driver 139 is according to the amount that is stored in the value control transmitted light in the video memory 133.Thereby, in LCD panel 1, be displayed in the position according to the synchronizing signal that comprises among the picture signal Vsig according to the image of picture signal Vsig.
As shown in Figure 1, when from the B coloured light of CCFL pipe 3 emissions and G coloured light with propagated from the R coloured light of LED 4 emissions blend of colors apart from the time, they are mixed to enter optics 2 as white light.By in the optics 2, the white light experience makes the intensity distributions homogenising, preceding directivity is provided, carries out the action of SP polarization conversion and so at white light, and white light enters LCD panel 1 then.LCD panel 1 is carried out the intensity in transmission modulation according to the picture signal from the input of image processing circuit (not shown) to each pixel.At this moment, the color filter (not shown) of the B of LCD panel 1, G and R. optionally allow B look wavelength coverage, G look wavelength coverage and R look wavelength coverage from the white light that optics 2 enters to pass through.Thereby coloured image is shown.
Next, the spectral-transmission characteristics of the color filter of the characteristic spectral emission of CCFL pipe 3 in the light supply apparatus 6 and LED4 and LCD panel 1 will be described below.Before the example of describing according to embodiment 1 to 3, comparative example 1 and 2 will be described.
Fig. 2 illustrates comparative example 1 and 2 and the table of the structure of the major part of the light supply apparatus of example 1 to 3.Fig. 2 illustrates the multiple light source (phosphor or LED) that is used for B coloured light, G coloured light and R coloured light, and the spectrum peak wavelength of B coloured light, G coloured light and R coloured light.In addition, in example. the NTSC ratio that shows employed energizing gas and obtained.
[comparative example 1]
Fig. 8 shows the spectrum of light supply apparatus of comparative example 1 and the color filter characteristic of LDC panel.In the figure, transverse axis indication wavelength (nm), the transmissivity (left vertical axle) of the emissive porwer (right side Z-axis) of the emission spectrum of Z-axis indication light source and the color filter of LCD panel.The unit of Z-axis is an arbitrary unit.
In this example, as shown in Figure 2, only used the CCFL pipe that utilizes B phosphor, G phosphor and R phosphor, and used mercury (Hg) as energizing gas as light supply apparatus.Used BaMgAl 10O 17Base phosphor (Kasei Optonix, the LP-B4 of Ltd.) as the B phosphor, has used LaPO 4: Ce, Tb (Kasei Optonix, the LP-G2 of Ltd.) is as the G phosphor.Used Y 2O 3: Eu (Kasei Optonix, the LP-RE1 of Ltd.) is as the R phosphor.In Fig. 8, the emission spectrum of W1 indication whole C CFL pipe, CFB, CFG and CFR indicate the spectral transmission spectrum of the color filter that is used for B, G and R of LCD panel respectively.
In the emission spectrum W1 of CCFL pipe, the peak PB of 450nm is the peak of B phosphor, and the peak PG1 of 545nm is the peak of G phosphor.The peak PR1 of 613nm is the peak of R phosphor.Used Hg as energizing gas, so emission line spectrum is included near the visible light of 404nm, 436nm, 546nm and 578nm.In these emission line spectrums of Hg, the peak PG1 of the emission line spectrum of 546nm and G phosphor coupling.
The colour gamut that is used as under the situation backlight at the CCFL pipe is illustrated by the T1 in the chromatic diagram shown in Figure 10 (long dotted line).In Figure 10, transverse axis indication x colourity, Z-axis indication y colourity.TN indication NTSC colour gamut.In this example, the NTSC ratio is low to reach 74.9% (with reference to figure 2), and colour gamut is narrower.The color B ultrasonic has been crossed the NTSC colour gamut, so color B is no problem; But in color G and color R, colourity is narrower, therefore needs to improve to be used as to show.
The narrower reason of colour gamut in the comparative example 1 is as follows.
Under the situation of LCD panel, the factor of determining the xy chroma point of R, the G of decision colour gamut and B is the degree of every kind of color wavelength ranges of the spectral-transmission favtor of the spectrum backlight color filter that disturbs the LCD panel.In the example depicted in fig. 8, in light, except the principal spectrum PG1 of 545nm, also observe inferior spectrum PGS1 at about 580nm place from the G phosphor of CCFL pipe.Therefore, comprise orange partially color in the wavelength coverage of the G of LCD panel colo(u)r filter, it is from the 545nm emission of G phosphor and the mixing of 580nm emission, thereby the colour gamut of color G reduces.Be also included near the inferior spectrum PGS1 the 580nm of G phosphor in the wavelength coverage of R colo(u)r filter of LCD panel, therefore inferior spectrum PGS1 mixes with principal spectrum PR1 from the 613nm of R phosphor, thereby consequently the colour gamut of color R also reduces.
In addition, the narrower colour gamut in the comparative example 1 is still caused by the emission spectrum from the R phosphor of CCFL pipe.Figure 11 is the figure that the emission spectrum of the R phosphor that uses in the CCFL pipe of comparative example 1 is shown.As shown in FIG., except the principal spectrum PR1 of 613nm, near 590nm and 545nm, also observed inferior spectrum PRS1 and PRS2 respectively, and inferior spectrum PRS1 and PRS2 be included in the wave band of color filter of color R, so they cause the reducing of colour gamut of G coloured light.
[comparative example 2]
Fig. 9 illustrates the spectrum of light supply apparatus of comparative example 2 and the color filter characteristic of LCD panel.Identical among the implication of transverse axis and Z-axis and Fig. 8.
In this example, identical with situation in the comparative example 1 as shown in Figure 2, only used the CCFL pipe that utilizes B phosphor, G phosphor and R phosphor as light supply apparatus, and used mercury as energizing gas.But, different with comparative example 1, used BaMgAl 10O 17Base phosphor (Kasei Optonix, the LP-G3 of Ltd.) as the G phosphor, has used YV 4O 3: Eu (Kasei Optonix, the MGV-620 of Ltd.) is as the R phosphor.Used with comparative example 1 in identical phosphor as the B phosphor.In Fig. 9, the emission spectrum of W2 indication whole C CFL pipe.Identical (with reference to figure 8) in the implication of CFB, CFG and CFR and the comparative example 1.
In the emission spectrum W2 of CCFL pipe, the peak PB of 450nm is the peak of B phosphor, and the peak PG2 of 514nm is the peak of G phosphor.The peak PR2 of 620nm is the peak of R phosphor.Owing to used Hg as energizing gas, so emission line spectrum is included near the visible light of 404nm, 436nm, 546nm and 578nm.
The colour gamut that is used as under the situation backlight at the CCFL pipe is illustrated by the T2 in the chromatic diagram shown in Figure 10 (short dash line).In this example, the NTSC ratio is 92.8% (with reference to figure 2), and compares colour gamut with comparative example 1 improvement is arranged greatly.Can think, owing to used emission to have to be positioned near the G phosphor of the light of the single peak PG2 the 514nm, therefore reduce in the comparative example 1 influence, and improve the colour gamut of color G near the inferior spectrum the 580nm of the G phosphor of CCFL pipe.In addition, can think,, improve the colour gamut of color R by moving to 620nm (PR2) near the 614nm of peak PR1 from comparative example 1.But, as shown in figure 12, comprise the inferior spectrum PRS3 of 595nm, so still have the factor that causes colour gamut to reduce from the emission spectrum of R phosphor.Figure 12 shows the emission spectrum of the every kind of color phosphor light quality that uses in the CCFL pipe of comparative example 2 and the emission line spectrum of mercury.In Figure 12, SB, SG and SR indicate the emission spectrum of B phosphor, G phosphor and R phosphor respectively, the emission line spectrum of SH indication mercury.
In chromatic diagram shown in Figure 10, T3 (dot-and-dash line) indication Japan is without the colour gamut of the LCD among the substantive examination public announcement of a patent application No.2004-163902, and T4 (double dot dash line) indication Japan is without the colour gamut of the LCD among the substantive examination public announcement of a patent application No.2004-294984.
Consider comparative example 1 and 2, formed example 1 to 3.
[example 1]
Fig. 3 shows the spectrum of light supply apparatus of example 1 and the color filter characteristic of LCD panel.Identical among the implication of transverse axis and Z-axis and Fig. 8.
In this example, the combination of having used the CCFL pipe 3 that has been applied in B phosphor and G phosphor and LED 4 is as light supply apparatus, and used mercury as energizing gas.Identical in the B phosphor of CCFL pipe 3 and G phosphor and the comparative example 2, LED 4 is the basic red light-emitting diodes (with reference to figure 2) of AlInGaP.In Fig. 3, the emission spectrum of the combination of W3 indication CCFL pipe and LED.Identical (with reference to figure 8) in the implication of CFB, CFG and CFR and the comparative example 1.
In emission spectrum W3, the peak PB of 450nm is the peak of the B phosphor of CCFL pipe 3.Near the peak PG2 of (in Fig. 3 for the 514nm) is the single spectrum with 30nm or littler half width 510 near 520nm, and is the peak of the G phosphor of CCFL pipe 3.Near the peak PR3 of 620 to 650nm (being the 638nm in Fig. 3) is the single spectrum with 25nm or littler half width, and is the peak of LED 4.Owing to use mercury as energizing gas, so emission line spectrum is included near the visible light of 404nm, 435nm, 546nm and 578nm.
In example 1, used the CCFL pipe as first light source; But, do not use the R phosphor, therefore removed the spectrum of being longer than 585nm.In addition, owing to used emission to have the G phosphor of the emission spectrum at the peak that is positioned at 510 to 520nm places, so alleviated the problem that the inferior spectrum PGS1 by 580nm in the comparative example 1 (with reference to figure 8) causes.On the other hand, therefore the LED 4 that has used the wavelength of peak (PR3) wherein to have 620 to 650nm single spectrum has eliminated the influence from the inferior spectrum PRS3 of the 595nm of R phosphor of the problem that causes in the comparative example 2 (with reference to figure 9).In addition, the wavelength of the emission spectrum peak PR3 of LED is positioned at outside the transmission peak wavelength scope CFG of green color filter of LCD panel 1, therefore can prevent a part of ruddiness by green color filter, thereby can prevent that redness is mixed in the green pixel, therefore can improve color reproduction.
The colour gamut that this light source is used as under the situation backlight is illustrated by the T5 in the chromatic diagram of Fig. 6 (long dotted line).In this example, the gamut extension of color G and R to realize 101.3% NTSC ratio (with reference to figure 2), is therefore compared with 2 with comparative example 1, and colour gamut is significantly improved.In addition, the indication of the TN among Fig. 6 NTSC colour gamut.
[example 2]
Fig. 4 shows the spectrum of light supply apparatus of example 2 and the color filter characteristic of LCD panel.Identical among the implication of transverse axis and Z-axis and Fig. 8.
In this example, the combination of having used the CCFL pipe 3 that is applied in B phosphor and G phosphor and LED4 is as light supply apparatus, and used inert gas xenon (Xe) as energizing gas (with reference to figure 2).Identical in other structures and the example 1.In Fig. 4, the emission spectrum of the combination of W4 indication CCFL pipe and LED.Identical (with reference to figure 8) in the implication of CFB, CFG and CFR and the comparative example 1.
In this example, owing to used inert gas xenon rather than mercury as energizing gas, so near the exclusive emission line spectrum of 404nm, 436nm, 546nm and 578nm of mercury has disappeared.The colour gamut that this light source is used as under the situation backlight is illustrated by the T6 in the chromatic diagram of Fig. 6 (short dash line).In this example, owing to there is not the emission line spectrum of the 546nm of mercury, so 510 to 520nm peak PG2 of G phosphor is single spectrum, and the colour gamut of color G further expands, to realize 104.5% NTSC ratio (with reference to figure 2).In addition, in this example, the wavelength of the emission spectrum peak PR3 of LED is positioned at outside the transmission peak wavelength scope CFG of green color filter of LCD panel 1, therefore can prevent that redness is mixed in the green pixel, thereby improve color reproduction.
[example 3]
Fig. 5 shows the spectrum of light supply apparatus of example 3 and the color filter characteristic of LCD panel.Identical among the implication of transverse axis and Z-axis and Fig. 8.
In this example, identical with situation in the example 2, the combination of having used the CCFL pipe 3 that is applied in B phosphor and G phosphor and LED 4 is as light supply apparatus, and used the inert gas xenon as energizing gas (with reference to figure 2).But different with example 2 is to have used the G phosphor Zn that uses among the PDP (Plasmia indicating panel) 2SiO 4: Mn (Kasei Optonix, the P1G of Ltd.) is as the G phosphor.As shown in Figure 7, from the emission spectrum of G phosphor have spike length be 520 to 530nm and half width be 45nm or littler single spectrum.Identical in other structures and the example 2.In addition, in Fig. 5, the emission spectrum of the combination of W5 indication CCFL pipe 3 and LED 4.Identical (with reference to figure 8) in the implication of CFB, CFG and CFR and the comparative example 1.
The colour gamut that this light source is used as under the situation backlight is illustrated by T7 (dot-and-dash line).In example 2, owing to use inert gas rather than mercury as energizing gas, so gamut extension; But the spike length of the emission spectrum of G phosphor is 510 to 520nm, and therefore this problem that spike length is moved to the left from the G colour gamut in the NTSC colour gamut occurred too near short wavelength's one side.On the other hand, in example 3, the peak PG3 of the single spectrum of G phosphor is 520 to 530nm, and to long wavelength's one side shifting, has therefore prevented on the chromatic diagram move to left (the color phase shifts) of G colour gamut.But the half width of the single spectrum of G phosphor is wideer than example 2 parts omitted, so the G colour gamut is slightly narrow, so the NTSC ratio is 98%.But, 98% NTSC colour gamut no better than, so color reproduction is sufficient.In addition, in this example, the wavelength of the emission spectrum peak PR3 of LED is positioned at outside the transmission peak wavelength scope CFG of green color filter of LCD panel 1, therefore can prevent that redness is mixed in the green pixel, thereby improve color reproduction.
Thereby, in this embodiment, the CCFL pipe 3 that has been applied in B phosphor and G phosphor but has been not applied to the R phosphor is used as light supply apparatus with the combination of LED 4, therefore eliminated the problem of influence of inferior spectrum of the 595nm of the R phosphor in the CCFL pipe that occurs in comparative example 2, thus can expanded color gamut.More specifically, in example 1 and 2, used emission to have to be positioned at the G phosphor of the emission spectrum at 510 to 520nm peak, therefore can alleviate the problem that occurs in the adverse effect that the inferior spectrum by 580nm in the comparative example 1 causes, and the G phosphor can work to gamut extension.Especially in example 2, used such as the such inert gas of xenon rather than mercury as energizing gas, therefore eliminated the exclusive emission line spectrum of mercury, thereby 510 to 520nm peak of G phosphor is a single spectrum, so the colour gamut of color G further expands.In addition, in example 3, and compare in the example 1 and 2, the peak of the single spectrum of G phosphor moves to longer wavelength one side. and therefore prevented on the chromatic diagram move to left (the color phase shifts) of G colour gamut, therefore can realize extraordinary color reproduction.In addition, be positioned at from the spike length of the ruddiness (single spectrum) of LED4 outside the transmission peak wavelength scope of green color filter of LCD panel 1, therefore prevented that redness is mixed in the green pixel, thereby colour gamut obtained expansion (having improved color reproduction).
In this embodiment, LED 4 is arranged directly between the CCFL pipe 3, and does not use optical plate, so LED 4 is particularly suitable for large high-strength TV.In addition, LED 4 be arranged at CCFL pipe 3 at a distance of a distance that makes it possible to take place the blend of colors of light, and the level after being arranged at such as diffusing panel 24 such diffusing members, therefore fully mixed with ruddiness from the blue light of CCFL pipe 3 and green glow, and they can be by diffusion subsequently from LED 4.Therefore, can obtain to have the white light that uniform strength distributes, and can prevent because the deterioration of the color reproduction that Strength Changes causes.
In addition, in this embodiment, color G and B are by using compared with only comprising that the backlight of LED has the CCFL pipe of higher light emission efficiency to generate, and the R look LED that has high light emission efficiency in LED is used to generate color R, thus power consumption compared with only comprise LED backlight come can be littler.
Though reference example has been described the present invention, the present invention is not limited to this embodiment, but can be subjected to various modifications.For example, do not adopt LED shown in Figure 1 to be arranged directly in direct type between the CCFL pipe, but as shown in figure 13, a plurality of LED 4 can be arranged on the side end face of optical plate 42, and optical plate 42 is arranged at the back side of CCFL pipe 3.By having formed surface source of light, therefore needn't strictly consider to make from the light of LED 4 and the distance that can mix from the light of CCFL pipe 3, thereby the result can easily reduce thickness backlight with optical plate 42.In the photoconduction template, led light source is arranged at the optical plate edge, so brightness is limited; But, have only color R among color R, G and the B by optical plate, so brightness is to pass through 1/3 of the brightness of the white light of blend color R, G and B generation.Therefore, be applied at the photoconduction template under the situation of TV, problem can not take place.As for thermal design, compare with direct type, led light source is concentrated, so advantage is to be easy to make their coolings.
In addition, in this embodiment, the situation that light supply apparatus is applied to direct type LCD has been described; But the present invention is not limited to this situation, and the present invention can be applied to the porjection type display.In addition, the present invention not only can be applied to transmission type lcd device, can also be applied to reflection LCD.In addition, for example, light supply apparatus can be used for any other to be used, for example as the illuminator of room lighting equipment.
It will be understood by those of skill in the art that according to design requirement and other factors, can carry out various modifications, combination, sub-portfolio and change, as long as they are within the scope of claims and equivalent thereof.
The present invention comprises Japanese patent application JP2005-212820 that submits to Jap.P. office with on July 22nd, 2005 and the relevant theme of submitting to Jap.P. office on May 12nd, 2006 of Japanese patent application JP2006-133290, and is by reference that the full content of these two patented claims is incorporated here.

Claims (7)

1. light supply apparatus comprises:
Cold cathode fluorescent tube, it comprises and is used for blue B phosphor and is used for green G phosphor; And
Be used for red light emitting diode;
Wherein, described G phosphor emission has 510 to 530nm the long single spectrum light of spike, and
Described light emitting diode emission has 620 to 650nm the long single spectrum light of spike.
2. light supply apparatus according to claim 1, wherein
Mercury gas is sealed in the described cold cathode fluorescent tube as energizing gas, and
Described G phosphor emission has 510 to 520nm the long single spectrum light of spike.
3. light supply apparatus according to claim 1, wherein
Xenon is sealed in the described cold cathode fluorescent tube as energizing gas.
4. light supply apparatus according to claim 3, wherein
Described G phosphor emission has 520 to 530nm the long single spectrum light of spike.
5. LCD comprises:
Light supply apparatus; And
Liquid crystal display, it comes display image by using from the light of described light supply apparatus emission as transillumination light,
Wherein said light supply apparatus comprises:
Cold cathode fluorescent tube, it comprises and is used for blue B phosphor and is used for green G phosphor; And
Be used for red light emitting diode, and
Described G phosphor emission has 510 to 530nm the long single spectrum light of spike, and
Described light emitting diode emission has 620 to 650nm the long single spectrum light of spike.
6. light supply apparatus as the backlight of liquid crystal display, described liquid crystal display comprises blue color filter, green color filter and the Red lightscreening plate that is used for color display, described light supply apparatus comprises:
Cold cathode fluorescent tube, it comprises and is used for blue B phosphor and is used for green G phosphor;
Be used for red light emitting diode, its be arranged at described cold cathode fluorescent tube at a distance of a distance that makes it possible to take place the blend of colors of light; And
Diffusion member, its diffusion be from the colorama of described cold cathode fluorescent tube emission with from the colorama of described light emitting diode emission, thereby owing to the blend of colors of light makes the intensity distributions of white light even,
The wherein said spike length that is used for the spectral light of red light emitting diode is positioned at outside the transmission peak wavelength scope of described green color filter, and the emission of described G phosphor has 510 to 530nm the long single spectrum light of spike.
7. LCD comprises:
Liquid crystal display, it comprises blue color filter, green color filter and Red lightscreening plate, with color display; And
As the light supply apparatus of the backlight of described liquid crystal display,
Wherein said light supply apparatus comprises:
Cold cathode fluorescent tube, it comprises and is used for blue B phosphor and is used for green G phosphor;
Be used for red light emitting diode, its be arranged at described cold cathode fluorescent tube at a distance of a distance that makes it possible to take place the blend of colors of light; And
Diffusion member, its diffusion be from the colorama of described cold cathode fluorescent tube emission with from the colorama of described light emitting diode emission, thereby owing to the blend of colors of light makes the intensity distributions of white light even,
The wherein said spike length that is used for the spectral light of red light emitting diode is positioned at outside the transmission peak wavelength scope of described green color filter, and the emission of described G phosphor has 510 to 530nm the long single spectrum light of spike.
CNB2006100994671A 2005-07-22 2006-07-20 Light source apparatus and liquid crystal display Expired - Fee Related CN100472295C (en)

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JP2005212820 2005-07-22
JP2005212820 2005-07-22
JP2006133290 2006-05-12

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