CN100437287C - High colour expression liquid crystal display - Google Patents

Abstract

The present invention relates to a liquid crystal display which is provided with a plurality of color light filters with red, green and blue pixels, and a back light source. When the value of the maximum brightness of the frequency spectrum of the back light source is arranged to be about 1.0, the sum of products of the frequency spectrum brightness of the back light source and the transmissivity of the color light filters with blue pixels in the wave length range of about 490 nanometers to about 540 nanometers is less than or equal to 2.0 roughly so that the transmissivity frequency spectrum of the color light filters is coordinated with that of the back light source. Thus, the maximum display colour gamut is achieved and can conform to corresponding color coordinates, which conforms to the requirements of human eyes for a color display.

Description

The LCD of high color representation

Technical field

The present invention relates to (high gamut) LCD of a kind of high color representation, particularly relate to the backlight that can utilize non-fluorescent tube, meet the LCD of human eye the demand of color representation.

Background technology

Tft liquid crystal display module (thin film transistor-liquid crystal displaymodule, TFT-LCD module) has been widely used in the display miscellaneous, is illustrated in figure 1 as the diagrammatic cross-section of TFT-LCD module.Yet, influence because of the optical characteristics of the colored filter of TFT-LCD module and liquid crystal, make that the color representation that the TFT-LCD module presented is more non-for saturated, so the high color rendition in the TFT-LCD module (color reproduction) just becomes one of important characteristic parameter.Hereat, international each normal structure is just formulated multiple color standard (as: NTSC, FCO, PAL, CIE, ... etc.), make the TFT-LCD module can provide and meet preferred color parameter, yet, employed backlight is the cathode-luminescence fluorescent tube in the existing TFT-LCD module, the NTSC (National Television Standard Committee, National Television System Committee (NTSC)) that causes the TFT-LCD module to be presented than being 75%, still is apparent not enough in the performance for color saturation.For satisfying user's demand, each manufacturer all is devoted to the exploitation of high color reproducing technology, wherein can utilize the kind of change backlight (back light source) and every variable coefficient of backlight to reach the target that improves NTCS.

Generally speaking, we can use multiple light-emitting component to be used as backlight, yet the pointolite characteristic of existing non-fluorescent tube, feasible collocation conventional cathode fluorescent tube ((Cathode Fluorescent Lamp, CFL), as: cathode fluorescent tube (Cold Cathode Fluorescent Lamp, CCFL)) colored filter is when the non-CFL light source of collocation, the situation that red, green, blue (RGB) three look color coordinate drift will occur, and then have influence on white point coordinate and the colour temperature of LCD, also can influence colour gamut simultaneously.As shown in Figure 2, in case when the backlight of LCD changed non-CFL backlight into by the CFL backlight, blue chromaticity coordinates can be toward the relatively poor direction skew of excitation, thereby influences colour gamut, and easily by human eye perception significantly.

Summary of the invention

Main points of the present invention are to make the transmissivity frequency spectrum of colored filter and backlight source spectrum to coordinate, and enable to reach maximum performance colour gamut and meet the demand of human eye to color representation.

LCD of the present invention comprises the colored filter and a backlight of a plurality of red, green, blue three color pixels, and the frequency spectrum of colored filter must meet following relational expression:

$\underset{490}{\overset{540}{\mathrm{\Σ}}}\mathrm{BL}\left(\mathrm{\λ}\right)\text{\×}{\mathrm{CF}}_{\mathrm{Blue}}\left(\mathrm{\λ}\right)\mathrm{\Δ\λ}\≤2.0$

Wherein BL (λ) is normalization (normalized is made as about 1.0 with the maximum intensity of a backlight) light source later.And CF _BlueTransmissivity for the colored filter of blue pixel.Both sum of products are about 490 nanometers (nm) between 540 nanometers (nm) in wavelength coverage, must be haply less than or equal 2.0 haply, blue point coordinate is meeted the requirements.In addition, the intensity BL of backlight (λ) also can other numerical value as normalization, but must meet above-mentioned formula, so that blue point coordinate meets the requirements.

Description of drawings

Figure 1 shows that the diagrammatic cross-section of TFT-LCD module.

Fig. 2 illustrate into the colored filter of the traditional cold cathode fluorescent lamp of existing collocation when the collocation led light source, the situation of red, green, blue (RGB) three look color coordinate drift appears.

Fig. 3 illustrate is the frequency spectrum backlight of first embodiment of the invention, the transmissivity of colored filter and the spectrogram of LCD.

Fig. 4 illustrate is the CIE figure of first embodiment of the invention.

Fig. 5 illustrate is the frequency spectrum backlight of second embodiment of the invention, the transmissivity of colored filter and the spectrogram of LCD.

Fig. 6 illustrate is the CIE figure of second embodiment of the invention.

Embodiment

According to the demand of human eye to color representation, International Standards Organization defines several color standards, and the present invention is an example with the standard criterion of TCO ' 03 (Sweden specialty employee alliance environment mark chapter), so other standard criterion also can be used, as: NTSC, PAL or other international standard criterion, and it is under the rough requirement that meets as table 1 of the chromaticity coordinates of red, green, blue three looks of those standard criterions palpus, also applicable.The red, green, blue three look chromaticity coordinates values of being formulated according to TCO ' 03 (u ', v '), the coordinate figure of itself and CIE 1931 chromaticity coordinates figure (chromaticity diagram) (x, transformational relation y) is:

u’＝4x/(-2x+12y+3)

v’＝9y/(-2x+12y+3)

LCD of the present invention comprises that one has the display panels and a backlight of the colored filter of a plurality of red, green, blue pixels.Wherein backlight is non-CFL backlight.Backlight comprises the light-emitting component or the white-light luminescent component of at least two kinds of different colors, can also comprise the light-emitting component of another color, and its color is different from two kinds of different colors one of them.And present embodiment is an example with ruddiness (R) light-emitting component, green glow (G) light-emitting component and blue light (B) light-emitting component, sends the white light with a colour temperature of being scheduled to.Yet the light-emitting component of other color also can be used in combination and send the white light with a predetermined colour temperature, as: white, yellow green, Chinese red, blue-green ... etc.Moreover, light-emitting component comprises light emitting diode (light emitting diode, LED), organic electroluminescent device (organicelectroluminescent device, OELD), electroluminescent cell (field emission device, FED) or similar light-emitting component, and present embodiment is example with the light emitting diode, then use the backlight of light emitting diode then to be referred to as the LED-backlit source, if use the backlight of organic illuminating element then to be referred to as the OELD backlight, if use the backlight of electroluminescent cell then to be referred to as the FED backlight.The RGB light-emitting component sends the light of predetermined wavelength after receiving the drive current of control module, make backlight module send to have the white light of a predetermined colour temperature after colour mixture.The following feature of its frequency spectrum tool, its blue crest scope is about 430nm to 480nm, and green crest scope is about 500nm to 550nm, and red crest scope is about 600nm to 650nm.

Because the colourity of LCD depends on the transmissivity of backlight source spectrum and colored filter, therefore for the blueness that makes LCD not reason CFL backlight change to non-CFL backlight (as: LED-backlit source) and then make point coordinate be offset, even depart from the range of definition (as: TCO ' 03) of standard criterion, in a preferred embodiment of the present invention, use the LCD in LED-backlit source, (as: Thin Film Transistor-LCD (TFT-LCD), low temperature polycrystalline silicon LCD (LTPS-LCD), or other similar LCD), the frequency spectrum of its colored filter must meet following relational expression:

$\underset{490}{\overset{540}{\mathrm{\Σ}}}\mathrm{BL}\left(\mathrm{\λ}\right)\text{\×}{\mathrm{CF}}_{\mathrm{Blue}}\left(\mathrm{\λ}\right)\mathrm{\Δ\λ}\≤2.0$

Wherein BL (λ) is normalization (normalized is made as about 1.0 with the maximum intensity of a backlight) light source later.And CF _BlueTransmissivity for the colored filter of blue pixel.Both and unit wavelength sum of products at the about 490nm of wavelength coverage between about 540nm, must be haply less than or equal 2.0 haply, the point coordinate of blueness is meeted the requirements.The intensity BL of backlight (λ) also can other numerical value as normalization, but must meet above-mentioned formula, so that blue point coordinate meets the requirements.

And for satisfying formula of the present invention, the parameter of the transmissivity of colored filter that can be by changing backlight source spectrum, blue pixel etc. is so that blue point coordinate meets the requirements.Now the transmissivity with the colored filter that changes blue pixel is an example, illustrate how to make LCD blueness not reason CFL backlight change to behind the LED-backlit source and make point coordinate be offset.

Please refer to table 2-1 and table 2-2, table 2-1 and table 2-2 are depicted as 2 embodiment of the present invention.With first embodiment is example, " #1 frequency spectrum backlight " be the brightness value of each wavelength; " normalized #1 frequency spectrum backlight " be the brightness value of frequency spectrum normalization backlight (normalized is a high-high brightness with about 1.0) each wavelength afterwards; " product of first embodiment " be the brightness value of each wavelength after the frequency spectrum normalization backlight and the product of the transmissivity of the colored filter of preferred blue pixel; " transmissivity of colored filter of existing blue pixel and the product of normalized #1 frequency spectrum backlight " be the product of transmissivity of the colored filter of the brightness value of each wavelength after the frequency spectrum normalization backlight and existing blue pixel.2-1 and 2-2 can learn by table, when the maximum brightness value of backlight source spectrum be made as about 1.0 the time, the transmissivity of luminance of backlight source spectrum and preferred blue color colo(u)r filter the about 490nm of wavelength coverage extremely the sum of products between about 540nm be about 1.471; When the maximum brightness value of backlight source spectrum is made as approximately 1.0, the transmissivity of luminance of backlight source spectrum and existing blue color colo(u)r filter is about 3.704 at the about 490nm of wavelength coverage to the sum of products between about 540nm.

With second embodiment is example, " #2 frequency spectrum backlight " be the brightness value of each wavelength; " normalized #2 frequency spectrum backlight " be the brightness value of frequency spectrum normalization backlight (normalized is a high-high brightness with 1) each wavelength afterwards; " product of second embodiment " be the brightness value of each wavelength after the frequency spectrum normalization backlight and the product of the transmissivity of the colored filter of preferred blue pixel; " transmissivity of colored filter of existing blue pixel and the product of normalized #2 frequency spectrum backlight " be the product of transmissivity of the colored filter of the brightness value of each wavelength after the frequency spectrum normalization backlight and existing blue pixel.2-1 and 2-2 can learn by table, when the maximum brightness value of backlight source spectrum be made as about 1.0, the transmissivity of luminance of backlight source spectrum and the colored filter of preferred blue pixel the about 490nm of wavelength coverage extremely the sum of products between about 540nm be about 1.143; When the maximum brightness value of backlight source spectrum is made as approximately 1.0, the transmissivity of the colored filter of luminance of backlight source spectrum and existing blue pixel is about 2.907 at the about 490nm of wavelength coverage to the sum of products between about 540nm.

Figure 3 shows that the frequency spectrum backlight of first embodiment, the transmissivity of colored filter and the spectrogram of LCD.When the maximum brightness value of backlight source spectrum is made as 1.0, the transmissivity of luminance of backlight source spectrum and blue color colo(u)r filter promptly be meant to the sum of products between about 540nm at the about 490nm of wavelength coverage backlight spectrum value and blue pixel colored filter transmissivity the product curve between about 490nm extremely between about 540nm with the formed area size of transverse axis.As shown in Figure 3, in the also long blue transmission rate of peak wavelength than the blue transmission rate of the colored filter of blue pixel, with the also short consistent wavelength of green transmissivity of peak wavelength, between about 490nm about 500nm extremely than the green transmissivity of the colored filter of green pixel.

Table 3 is depicted as the chromaticity coordinates figure of first embodiment.As shown in table 3, and the chromaticity coordinates of first embodiment (u ', v ') be red (0.542,0.516), green (0.077,0.576), blue (0.168,0.163) meets TCO ' 03 standard.Its chromaticity coordinates corresponding to CIE figure (x y) is red (0.697,0.295), green (0.213,0.710), and blue (0.145,0.063) can be learnt for color representation by this CIE figure to have clear improvement.

Figure 4 shows that the CIE figure of first embodiment.Can learn by Fig. 4, when the maximum brightness value of backlight source spectrum is made as about 1.0, the transmissivity of the colored filter of luminance of backlight source spectrum and blue pixel the sum of products of the about 490nm of wavelength coverage between about 540nm for haply less than or equal 2.0 haply, its colour gamut shows the standard criterion that can satisfy TCO ' 03.

Figure 5 shows that the frequency spectrum backlight of second embodiment, the transmissivity of colored filter and the spectrogram of LCD.In Fig. 5, when the maximum brightness value of backlight source spectrum be made as about 1.0, the transmissivity of the colored filter of luminance of backlight source spectrum and blue pixel promptly be meant to the sum of products between about 540nm at the about 490nm of wavelength coverage backlight spectrum value and blue pixel colored filter transmissivity the product curve between about 490nm extremely between about 540nm with the formed area size of transverse axis.As shown in Figure 5, in the also long blue transmission rate of peak wavelength than the blue transmission rate of the colored filter of blue pixel, with the also short consistent wavelength of green transmissivity of peak wavelength, between about 490nm about 500nm extremely than the green transmissivity of the colored filter of green pixel.

Table 4 is depicted as the chromaticity coordinates figure of second embodiment.As shown in table 4, and the chromaticity coordinates of second embodiment (u ', v ') be red (0.546,0.516), green (0.076,0.576), blue (0.168,0.160) meets TCO ' 03 standard.Its chromaticity coordinates corresponding to CIE figure (x y) is red (0.700,0.294), green (0.212,0.711), and blue (0.145,0.061) can be learnt for color representation by this CIE figure to have clear improvement.

Figure 6 shows that the CIE figure of second embodiment.Can learn by Fig. 6, when the maximum brightness value of backlight source spectrum is made as about 1.0, the transmissivity of the colored filter of luminance of backlight source spectrum and blue pixel the sum of products of the about 490nm of wavelength coverage between about 540nm for haply less than or equal 2.0 haply, its colour gamut shows the standard criterion that can satisfy TCO ' 03.

Though, embodiments of the invention all are to be best practice to be made as about 1.0 when the maximum brightness value of backlight source spectrum, this is to reduce to the interference parameter of the brightness problem of backlight minimum, to reach easier way, yet, the maximum brightness value of backlight source spectrum is not to be made as about 1.0 o'clock, can use embodiments of the present invention yet, as long as it meets relational expression of the present invention.

The above only is the preferred embodiments of the present invention, and all equalizations of doing according to claim of the present invention change and modify, and all should belong to covering scope of the present invention.

Table 1 is the standard criterion according to TCO ' 03, the chromaticity coordinates of red, green, blue three looks.

Table 2-1 and table 2-2 are 2 embodiment data of the present invention.

Table 3 is the chromaticity coordinates of red, green, blue three looks of first embodiment.

Table 4 is the chromaticity coordinates of red, green, blue three looks of second embodiment.

Table 2-1

Table 2-2

Claims (12)

1. LCD, colored filter and backlight with a plurality of red, green, blue pixels is characterized by:

When the maximum brightness value of this backlight source spectrum is made as 1.0, the transmissivity of the colored filter of this luminance of backlight source spectrum and these blue pixel, the sum of products between wavelength coverage 490nm to 540nm is less than or equal to 2.0.

2. LCD as claimed in claim 1, wherein in the also long blue transmission rate of peak wavelength than the blue transmission rate of the colored filter of these blue pixel, with the also short consistent wavelength of green transmissivity of peak wavelength, between 490nm to 500nm than the green transmissivity of the colored filter of these green pixels.

3. LCD as claimed in claim 1, wherein this backlight is non-negative electrode fluorescent tube backlight.

4. LCD as claimed in claim 3, wherein this non-negative electrode fluorescent tube backlight comprises the light-emitting component or the white-light luminescent component of at least two different colors.

5. LCD as claimed in claim 4, wherein this light-emitting component comprises light emitting diode, organic illuminating element, electroluminescent cell or its combination.

6. LCD as claimed in claim 4, this non-negative electrode fluorescent tube backlight wherein also comprise the light-emitting component of another color, and its color is different from one of them person of these different colors.

7. LCD comprises:

Liquid crystal panel has colored filter, and it has a plurality of red, green, blue pixels; And

Backlight give this liquid crystal panel in order to light source to be provided, and the transmissivity of the colored filter of this luminance of backlight source spectrum and these blue pixel has relational expression:

$\underset{490}{\overset{540}{\mathrm{\Σ}}}\mathrm{BL}\left(\mathrm{\λ}\right)\×{\mathrm{CF}}_{\mathrm{Blue}}\left(\mathrm{\λ}\right)\mathrm{\Δ\λ}\≤2.0$

Wherein, BL (λ) is the brightness of backlight, CF _Blue(λ) be the transmissivity of the colored filter of blue pixel.

8. LCD as claimed in claim 7, wherein in the also long blue transmission rate of peak wavelength than the blue transmission rate of the colored filter of these blue pixel, with the also short consistent wavelength of green transmissivity of peak wavelength, between 490nm to 500nm than the green transmissivity of the colored filter of these green pixels.

9. LCD as claimed in claim 7, wherein this backlight is non-negative electrode fluorescent tube backlight.

10. LCD as claimed in claim 9, wherein this non-negative electrode fluorescent tube backlight comprises the light-emitting component or the white-light luminescent component of at least two different colors.

11. LCD as claimed in claim 10, wherein this light-emitting component comprises light emitting diode, organic illuminating element, electroluminescent cell or its combination.

12. LCD as claimed in claim 10, wherein this non-negative electrode fluorescent tube backlight also comprises the light-emitting component of another color, and its color is different from one of them person of these different colors.

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