JP2009162979A - Color filter and liquid crystal display with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter in which the electric property of a colored layer of the color filter does not adversely affect the switching performance of a liquid crystal and in which sufficient performance can be secured and which can satisfy high color reproducibility without installing a protective layer (overcoat layer) with transparent resin, in a transverse electric field system liquid crystal display and to provide the liquid crystal display with the color filter. <P>SOLUTION: The color filter used for the liquid crystal display has a white backlight color-mixed by combining a red LED, a green LED and a blue LED and a color filter provided with colored layers of at least red, green and blue pixels, wherein the colored layer forming the green pixel includes a Pigment Green 36, the Pigment Green 36 content is ≤18 wt.% and the dielectric loss tangent (tan δ) of the colored layer forming the green pixel is ≤0.03 in a driving frequency of the liquid crystal display and in the vicinity thereof. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a color filter for a liquid crystal display device, and in particular, in a horizontal electric field type liquid crystal display device, the color filter in which the electrical properties of the colored layer of the color filter do not adversely affect the switching performance of the liquid crystal. And a liquid crystal display device including the same.

  Color liquid crystal display devices are rapidly spreading mainly in computer terminal display devices and television image display devices. The color filter is an indispensable important component for color display of a liquid crystal display device. In recent years, this liquid crystal display device has a high demand for higher image quality, and various new types of liquid crystal display devices having a high viewing angle and high-speed response have appeared. Among these, the horizontal electric field method (In Plane Switching = IPS method) is a method that is widely used because it has excellent display quality such as viewing angle and contrast ratio.

  However, unlike other Twisted Nematic systems (TN systems) and Vertical Alignment systems (VA systems), a horizontal electric field type liquid crystal display device has a colored layer of a color filter in a liquid crystal driving electric field, and therefore, There is a problem that it is directly affected by the electrical characteristics of the material. In fact, when Pigment Green 36 is used for a conventional colored layer material, particularly a green pixel colored layer, in a horizontal electric field type liquid crystal display device, liquid crystal alignment disorder due to the electrical characteristics of the colored layer material, switching threshold deviation Various display defects such as image burn-in phenomenon occurred due to. The electrical characteristics of the colored layer material are mainly due to the properties of the pigment itself, which is a colorant.

In order to relax the electrical characteristics of the colored layer material and avoid display defects,
When a color filter using Green 36 is used in a horizontal electric field type liquid crystal display device, as disclosed in Patent Document 1, it is common to provide a protective layer (overcoat layer) made of a transparent resin. However, the price of liquid crystal display devices in recent years has been remarkably reduced, and the color filter that is a member of the liquid crystal display device has been required to be reduced in price, and a color filter that can be used without providing a protective layer is desired.

On the other hand, as a method for improving electrical characteristics, as disclosed in Patent Document 2, a pigment green is used as a color index number contained in a colored layer of a green pixel.
A method of reducing the amount of 36 has also been proposed. However, since the coloring power of the colored layer is reduced by reducing the Pigment Green 36 contained in the colored layer of the green pixel, there is a problem that the liquid crystal display device cannot cope with the recent trend of demanding high color reproducibility. there were.
JP 2004-117537 A JP 2006-113099 A

  The present invention has been made to solve the above-described problems, and the object of the present invention is, in particular, in a horizontal electric field type liquid crystal display device, the electrical property of the colored layer of the color filter is the switching performance of the liquid crystal. Provided are a color filter capable of ensuring sufficient performance without providing a protective layer (overcoat layer) made of a transparent resin without being adversely affected by the transparent resin, and capable of corresponding to high color reproducibility, and a liquid crystal display device including the color filter There is.

  The invention according to claim 1 of the present invention is a liquid crystal having a white backlight in which red LED, green LED, and blue LED are combined and mixed, and a color filter having a colored layer of at least red, green, and blue pixels. In the color filter used in the display device, the colored layer forming the green pixel includes Pigment Green 36, the content of the Pigment Green 36 is 18% by weight or less, and the colored layer forming the green pixel The color filter is characterized in that the dielectric loss tangent (tan δ) is 0.03 or less at and near the driving frequency of the liquid crystal display device.

  According to a second aspect of the present invention, there is provided a white backlight in which red LED, green LED and blue LED are combined and mixed, and a color filter having a colored layer of at least red, green and blue pixels. In the color filter used for the liquid crystal display device having the above, the emission peak wavelength of the green LED of the white backlight is 500 to 540 nm, and the color reproducible range in the xy chromaticity diagram which is the CIE1931 XYZ color system is 72% in terms of NTSC ratio. The color filter according to claim 1, wherein the color filter is as described above.

  The invention according to claim 3 of the present invention is the color filter according to claim 1 or 2, further comprising a protective layer made of a transparent resin on the colored layer.

  According to a fourth aspect of the present invention, there is provided a liquid crystal display device comprising the color filter according to any one of the first to third aspects.

  According to a fifth aspect of the present invention, there is provided a horizontal electric field type liquid crystal display device comprising the color filter according to any one of the first to third aspects.

  The present invention relates to a color filter used in a liquid crystal display device having a white backlight in which red LED, green LED, and blue LED are mixed and a color filter having a colored layer of at least red, green, and blue pixels. The colored layer forming the green pixel includes Pigment Green 36 of 18% by weight or less, and the dielectric loss tangent (tan δ) of the colored layer is 0.03 or less at the driving frequency of the liquid crystal display device and the vicinity thereof. A color filter that does not adversely affect the display performance without disturbing the orientation of the liquid crystal or shifting the switching threshold without using a transparent resin protective layer (overcoat layer) when used in a horizontal electric field liquid crystal display device. In addition, a liquid crystal display device including the same can be provided.

  In addition, the present invention uses a white backlight in which the emission peak wavelength of the green LED is 500 to 540 nm in a white backlight in which a red LED, a green LED, and a blue LED are mixed and mixed as a backlight. Provided is a color filter capable of realizing a color reproducibility necessary for a television image display device, that is, a color reproducible range in an xy chromaticity diagram which is a CIE1931 XYZ color system of 72% or more in NTSC ratio, and a liquid crystal display device including the color filter It becomes possible to do.

  Below, the color filter by this invention is demonstrated in detail based on the one Embodiment.

  As a result of various studies on the relationship between the electrical properties of the color filter and the display defect in the horizontal electric field type liquid crystal display device, the present inventor has found that the liquid crystal alignment defect and the switching threshold deviation of the horizontal electric field type liquid crystal display device are mainly colored layers. We have found that this is caused by the dielectric properties of the material. Specifically, it can be explained by the value of the dielectric loss tangent, and is generally based on the following mechanism.

  The dielectric loss tangent (tan δ) is the ratio between the amount of charge accumulated in the dielectric and the amount of charge consumed. When the dielectric loss tangent is relatively small, the charge accumulated in the dielectric is retained, whereas when the dielectric loss tangent is relatively large, the charge is consumed and not retained.

  In the horizontal electric field type liquid crystal display device, the colored layer of the color filter is inherent in the liquid crystal driving electric field. Therefore, in the horizontal electric field type color liquid crystal display device, the dielectric loss tangent of the colored layer of the color filter and other members in the cell When the value of the dielectric loss tangent of (liquid crystal, alignment film, etc.) is greatly different, a phenomenon that the charge holding state becomes non-uniform occurs. The non-uniform charge retention state should not occur in a horizontal electric field type liquid crystal display device, a vertical electric field is generated and liquid crystal alignment failure occurs, or an extra charge remains. This causes a display failure such that burn-in occurs due to a threshold deviation caused by the above. Therefore, the dielectric loss tangent of the color layer material of the color filter is an important characteristic that determines the display characteristics of the horizontal electric field type liquid crystal display device. The dielectric loss tangent is a value depending on the measurement frequency, but it is appropriate to pay attention to the dielectric loss tangent in the vicinity of the liquid crystal driving frequency. Currently, one frame of the liquid crystal driving is about 60 Hz, so the period (second), that is, the frequency Therefore, it is appropriate to pay attention to the dielectric loss tangent at a frequency of approximately 10 to 100 Hz around 30 Hz.

  In general, a liquid crystal material, an alignment film material, and the like have a large ability to hold electric charges, that is, a material having a relatively small dielectric loss tangent, and its value is generally about 0.005 to 0.02. Accordingly, it is considered that the value of the dielectric loss tangent of the color layer material of the color filter used in the horizontal electric field type liquid crystal display device is preferably the same value as the liquid crystal material and the alignment film material.

  Here, the measurement results of the dielectric loss tangent of several kinds of colored layer materials of the color filter are shown in FIG. 1, FIG. 2, and FIG. The dielectric loss tangent of the colored layer of the color filter has a value of about 0.006 to 0.2 depending on the kind of the colored layer material in the vicinity of the liquid crystal driving frequency, that is, in the range of 10 Hz to 100 Hz. Of these, many of the green pixel coloring layer materials have large dielectric loss tangents. In fact, in the case of green pixels, pixel alignment defects, threshold deviations, etc. are likely to occur remarkably unless an overcoat layer is provided. It was.

  The present inventor has made various studies on this characteristic dielectric characteristic in order to eliminate pixel threshold deviation, alignment failure, and the like, thereby improving display quality.

  As a result, in the multicolored color filter for liquid crystal display devices, the dielectric loss tangent of the coloring layer material is set to 0.03 or less, more preferably 0.02 or less in the vicinity of the liquid crystal driving frequency, that is, in the range of 10 Hz to 100 Hz. Thus, it has been found that it is possible to effectively prevent deterioration in display quality such as pixel orientation failure and threshold shift without providing an overcoat layer. Although it is preferable that the dielectric loss tangent of the colored layer material is generally low, the lower limit is about 0.005 to 0.006 due to the characteristics of the material.

  In order to satisfy these characteristics, a white backlight in which red LED, green LED, and blue LED are combined and mixed is used as a backlight of a liquid crystal display device, and a color layer forming a green pixel is used in a color filter. The content of Pigment Green 36 is 18% by weight or less.

  If the content of Pigment Green 36 exceeds 18% by weight, the dielectric loss tangent exceeds 0.03 due to the characteristics of Pigment Green 36 as described above. Although the color purity is lowered due to a decrease in the content of Pigment Green 36, the emission peak wavelength of the green LED is 500 to 540 nm in a white backlight in which a red LED, a green LED, and a blue LED are mixed as a backlight. By using a certain white backlight, the color reproducibility necessary for a general television image display device, that is, the color reproducible range in the xy chromaticity which is the CIE1931 XYZ color system can be 72% or more in NTSC ratio. It becomes possible. However, if the content of Pigment Green 36 is extremely low, the color reproduction required for a general television image display device is possible even when a white backlight in which red LED, green LED, and blue LED are mixed as a backlight is used. Since it becomes difficult to realize the possible range, the content of Pigment Green 36 is desirably 10% by weight or more when a general television image display apparatus is used as a main application. However, this does not apply when considering other uses.

In addition, it is desirable that the colored layer forming the green pixel contains Pigment Yellow 150 or Pigment Yellow 138 together with Pigment Green 36, and the content of these pigments is a combination of a red LED, a green LED, and a blue LED as a backlight. In order to realize a color reproducible range necessary for a general television image display device using a mixed white backlight, Pigment Green
It is preferable to contain the same weight as 36 to about twice the weight. These pigments may be used alone or in combination as necessary. Furthermore, you may contain another yellow pigment as needed.

<Color filter>
Next, a method for obtaining the color filter of the present invention will be described. The color filter may be manufactured by any known method such as an inkjet method, a printing method, a photoresist method, or an etching method. However, in consideration of high definition, controllability and reproducibility of spectral characteristics, the photoresist method is preferable. That is, a pigment is dispersed in a suitable solvent together with a photoinitiator and a polymerizable monomer in a transparent resin to obtain a photosensitive coloring composition. After coating this photosensitive coloring composition on a transparent substrate and forming a film, the photosensitive coloring layer is subjected to pattern exposure and development to form a colored pattern of one color. This process is repeated for each color to produce a color filter.

  The transparent substrate used in the color filter of the present invention may be one generally used in a liquid crystal display device, and usually a glass substrate is preferably used. When using a light-shielding pattern, it is sufficient to use a light-shielding resin pattern previously provided on the transparent substrate by a known method.

  First, a pigment is dispersed in a suitable solvent together with a photoinitiator and a polymerizable monomer in a transparent resin to obtain a photosensitive coloring composition. There are various methods such as mill base, three rolls, jet mill and the like, and there are no particular limitations.

  Next, the above-mentioned photosensitive coloring composition is applied onto a transparent substrate and prebaked. Spin coating, dip coating, die coating, and the like are usually used as the means for coating, but are not limited to these as long as they can be coated on the transparent substrate with a uniform film thickness. Prebaking is preferably performed at 50 to 120 ° C. for about 10 to 20 minutes. The coating film thickness is arbitrary, but considering the spectral transmittance and the like, the film thickness after pre-baking is usually about 2 μm. The transparent substrate coated with the photosensitive coloring composition is exposed through a pattern mask. A normal high-pressure mercury lamp or the like may be used as the light source.

  Subsequently, development is performed. An alkaline aqueous solution is used as the developer. Examples of the alkaline aqueous solution include a sodium carbonate aqueous solution, a sodium hydrogen carbonate aqueous solution, a mixed aqueous solution of the two, or a mixture obtained by adding an appropriate surfactant to them. After development, the pattern is obtained by washing with water and drying.

  By repeating the above-described series of steps by changing the photosensitive coloring composition and the pattern as many times as necessary, a colored pattern in which the necessary number of colors are combined can be obtained.

  As described above, the color filter of the present invention does not require an overcoat layer because the colored layer has good electrical characteristics. However, in order to further improve the solvent resistance of the color filter or to make the surface more flat. It is also possible to provide a protective layer made of a transparent resin for the purpose of doing so.

<Backlight device>
Next, a method for obtaining the backlight used in the present invention will be described. The backlight device used in the present invention refers to a planar light source device disposed on the back surface of a liquid crystal panel and used as a back light source means of a transmissive or transflective color liquid crystal display device. LED of three colors that emit light in the wavelength range of the light source, and light uniformizing means for converting the light source light into a substantially uniform surface light source.

  The backlight device includes an LED light source, a reflector that reflects light emitted from the light source toward the viewer, and a light-transmitting flat plate that is used as a light guide for guiding light from the light source into a planar shape. It is configured by appropriately arranging a substrate, a light control sheet on which a triangular prism array is formed, and the like. As a light source installation method, a light source is disposed directly under the back surface of the liquid crystal element (directly under method), or a light source is disposed on the side surface and a light-transmitting light guide such as an acrylic plate is used to direct light into a planar shape. A typical method is a method (side light method) in which a surface light source is obtained by converting into a light source. For applications that require high luminance, the direct method is suitable, and for applications that require a reduction in thickness, the sidelight method is suitable.

  As the LED light source, an LED having a main emission wavelength in the red, green, and blue wavelength regions is generally used. Examples of LEDs having a main emission wavelength in the red region include GaAsP-based LEDs, LEDs having a main emission wavelength in the green region include GaP-based LEDs, and LEDs having a main emission wavelength in the blue region include InGaN-based LEDs. And GaN-based LEDs.

  Hereinafter, specific examples of the present invention will be described by way of examples. However, the present invention is not limited to these examples without departing from the spirit of the present invention.

<Photosensitive coloring composition>
The following pigments were used as colorants for coloring the photosensitive coloring composition used for the production of the color filter, and red, green and blue photosensitive coloring compositions were produced using the respective pigments.

Red pigment: C.I. I. Pigment Red 254 (“Ilgar Forred B-CF” manufactured by Ciba Specialty Chemicals), C.I. I. Pigment Red 177 (“Chromophthal Red A2B” manufactured by Ciba Specialty Chemicals), and C.I. I. Pigment Yellow 150 ("Fanchon First Yellow Y-5688" manufactured by LANXESS)
Green pigment: C.I. I. Pigment Green 36 (“Lionol Green 6YK” manufactured by Toyo Ink), C.I. I. Pigment Yellow 150 (“Fanchon First Yellow Y-5688” manufactured by LANXESS), and C.I. I. Pigment Yellow 138 ("Ariotor Yellow K0961HD" manufactured by BASF)
Blue pigment: C.I. I. Pigment Blue 15 (“Rionol Blue ES” manufactured by Toyo Ink) C.I. I. Pigment Violet 23 (BASF "Paliogen Violet 5890")
<Red photosensitive coloring composition>
A mixture having the following composition was uniformly stirred and mixed, then dispersed in a sand mill for 5 hours using glass beads having a diameter of 1 mm, and then filtered through a 5 μm filter to prepare a red pigment dispersion.

Red pigment: C.I. I. Pigment Red 254 10 parts Red pigment: C.I. I. Pigment Red 177 10 parts Yellow pigment: C.I. I. Pigment Yellow 150 5 parts Acrylic varnish (solid content 20%) 96 parts Cyclohexanone 112 parts Thereafter, a mixture of the following composition was stirred and mixed uniformly, and then filtered through a 5 μm filter to obtain a red photosensitive coloring composition. It was.

Dispersion of the above red pigment 233 parts Acrylic varnish (solid content 20%) 41 parts Caprolactone-modified dipentaerythritol hexaacrylate
(Nippon Kayaku “Kayarad DPCA30”) 13 parts Photoinitiator (Ciba Specialty Chemicals)
“Irgacure OXE-02”) 3 parts Photoinitiator (“Kayacure DETX” manufactured by Nippon Kayaku) 1 part Cyclohexanone 208 parts <Green photosensitive coloring composition 1>
It produced with the method similar to a red photosensitive coloring composition so that a composition might become the following composition, respectively.

Green pigment: C.I. I. Pigment Green 36 16 parts Yellow Pigment: C.I. I. Pigment Yellow 150 16 parts Acrylic varnish (solid content 20%) 212 parts Dipentaerythritol hexaacrylate
(“Aronix M402” manufactured by Toagosei Co., Ltd.) 17 parts Photoinitiator (Ciba Specialty Chemicals)
"Irgacure OXE02") 6 parts Photoinitiator ("Lucirin TPO" manufactured by BASF) 3 parts Cyclohexanone 458 parts <Green photosensitive coloring composition 2>
It produced with the method similar to a red photosensitive coloring composition so that a composition might become the following composition, respectively.

Green pigment: C.I. I. Pigment Green 36 25 parts Yellow Pigment: C.I. I. Pigment Yellow 150 11 parts Acrylic varnish (solid content 20%) 216 parts Dipentaerythritol hexaacrylate
(“Aronix M402” manufactured by Toagosei Co., Ltd.) 17 parts Photoinitiator (Ciba Specialty Chemicals)
"Irgacure OXE02") 6 parts Photoinitiator ("Lucirin TPO" manufactured by BASF) 3 parts Cyclohexanone 273 parts <Green photosensitive coloring composition 3>
It produced with the method similar to a red photosensitive coloring composition so that a composition might become the following composition, respectively.

Green pigment: C.I. I. Pigment Green 36 8 parts Yellow Pigment: C.I. I. Pigment Yellow 150 19 parts Acrylic varnish (solid content 20%) 221 parts Dipentaerythritol hexaacrylate
(“Aronix M402” manufactured by Toagosei Co., Ltd.) 18 parts Photoinitiator (Ciba Specialty Chemicals)
"Irgacure OXE02") 6 parts Photoinitiator ("Lucirin TPO" manufactured by BASF) 3 parts Cyclohexanone 373 parts <Green photosensitive coloring composition 4>
It produced with the method similar to a red photosensitive coloring composition so that a composition might become the following composition, respectively.

Green pigment: C.I. I. Pigment Green 36 16 parts Yellow Pigment: C.I. I. Pigment Yellow 138 16 parts Acrylic varnish (solid content 20%) 212 parts Dipentaerythritol hexaacrylate
(“Aronix M402” manufactured by Toagosei Co., Ltd.) 17 parts Photoinitiator (Ciba Specialty Chemicals)
"Irgacure OXE02") 6 parts Photoinitiator ("Lucirin TPO" manufactured by BASF) 3 parts Cyclohexanone 458 parts <Green photosensitive coloring composition 5>
It produced with the method similar to a red photosensitive coloring composition so that a composition might become the following composition, respectively.

Green pigment: C.I. I. Pigment Green 36 25 parts Yellow Pigment: C.I. I. Pigment Yellow 138 11 parts Acrylic varnish (solid content 20%) 216 parts Dipentaerythritol hexaacrylate
(“Aronix M402” manufactured by Toagosei Co., Ltd.) 17 parts Photoinitiator (Ciba Specialty Chemicals)
“Irgacure OXE02”) 6 parts Photoinitiator (“Lucirin TPO” manufactured by BASF) 3 parts Cyclohexanone 273 parts <Green photosensitive coloring composition 6>
It produced with the method similar to a red photosensitive coloring composition so that a composition might become the following composition, respectively.

Green pigment: C.I. I. Pigment Green 36 8 parts Yellow Pigment: C.I. I. Pigment Yellow 138 19 parts Acrylic varnish (solid content 20%) 221 parts Dipentaerythritol hexaacrylate
(“Aronix M402” manufactured by Toagosei Co., Ltd.) 18 parts Photoinitiator (Ciba Specialty Chemicals)
"Irgacure OXE02") 6 parts Photoinitiator ("Lucirin TPO" manufactured by BASF) 3 parts Cyclohexanone 373 parts <Blue photosensitive coloring composition>
It produced with the method similar to a red photosensitive coloring composition so that a composition might become the following composition, respectively.

Blue pigment: C.I. I. Pigment Blue 15 32 parts Purple Pigment: C.I. I. Pigment Violet 23 3 parts Acrylic varnish (solid content 20%) 173 parts Dipentaerythritol hexaacrylate
(Toagosei "Aronix M402") 25 parts Photoinitiator (Ciba Specialty Chemicals)
"Irgacure 379") 6 parts Photoinitiator ("Kayacure DETX" manufactured by Nippon Kayaku) 2 parts Cyclohexanone 302 parts <Color filter>
A color filter was produced using the photosensitive coloring composition obtained. The red photosensitive coloring composition was applied to a glass substrate by spin coating so as to have a film thickness of 2 μm. After drying, striped pattern exposure was performed with an exposure machine, and development was performed with an alkaline developer for 90 seconds to obtain a colored layer of striped red pixels. The alkaline developer has the following composition.

Sodium carbonate 1.5% by weight
Sodium bicarbonate 0.5% by weight
Anionic surfactant 8.0% by weight
("Peralex NBL" manufactured by Kao Corporation)
90% by weight of water
Next, the green photosensitive coloring composition is similarly applied by spin coating so as to have a film thickness of 2 μm, and after drying, the striped colored layer is shifted from the colored layer of the red pixel by an exposure machine. By exposing and developing in the above place, a colored layer of a green pixel adjacent to the colored layer of the red pixel was obtained.

  Further, in the same manner as for red and green, a blue photosensitive coloring composition having a film thickness of 2 μm was obtained, and a blue pixel coloring layer adjacent to the red and green pixel coloring layers was obtained. Thus, a color filter having a striped colored layer of three colors of red, green and blue on the transparent substrate was obtained.

  The combination of the red pixel colored layer, the green pixel colored layer, and the blue pixel colored layer is appropriately changed by the above-described method, and used in Examples 1 and 2 and Comparative Examples 1 to 10, respectively, as shown in Tables 1 and 2. A color filter was prepared and evaluated for comparison. In addition, the color reproducibility and operation stability of the liquid crystal display device were evaluated by combining the produced color filter and the backlight. The evaluation results are shown in Tables 1 and 2 as Examples 1 and 2 and Comparative Examples 1 to 10. The main comparison contents were a comparison of the concentration of the green pigment in the green pixel coloring layer with respect to the solid content, the dielectric loss tangent of the green pixel coloring layer at 20 Hz, and the NTSC ratio. O in the table indicates the judgment of the inventor.

なお、実施例および比較例に用いたＬＥＤ（Ｌｉｇｈｔ Ｅｍｉｔｔｉｎｇ Ｄｉｏｄｅ＝発光ダイオード）バックライトの相対分光放射輝度を図４に、ＣＣＦＬ（Ｃｏｌｄ Ｃａｔｈｏｄｅ Ｆｌｕｏｒｅｓｃｅｎｔ Ｌａｍｐ＝冷陰極管）バックライトの相対分光放射輝度を図５に示す。

The relative spectral radiance of the LED (Light Emitting Diode) backlight used in the examples and comparative examples is shown in FIG. 4, and the relative spectral radiance of the CCFL (Cold Cathode Fluorescent Lamp = cold cathode tube) backlight is shown in FIG. As shown in FIG.

<Comparison result>
In the liquid crystal display device using the color filter and the LED backlight of the first and second embodiments, good color reproducibility is obtained, and good display quality can be obtained without causing poor liquid crystal alignment of the pixel and threshold voltage deviation of the driving voltage. It was.

  In contrast to the first and second embodiments of the present invention, in the liquid crystal display device using the color filter and the LED backlight of the first and third comparative examples, the liquid crystal alignment defect of the pixel and the burn-in phenomenon due to the threshold shift of the driving voltage occur. Good display characteristics could not be obtained.

  Further, in the liquid crystal display devices using the color filters and LED backlights of Comparative Examples 2 and 4, the color reproducible range was small and the display quality was unsuitable for a television image display device.

  Further, in the liquid crystal display devices using the color filters of Comparative Examples 5, 6, 8, and 10 and the CCFL backlight, the color reproducible range was small and the display quality was unsuitable for a television image display device.

  In the liquid crystal display device using the color filter and the CCFL backlight of Comparative Examples 7 and 9, the liquid crystal alignment defect of the pixel and the burn-in phenomenon due to the threshold shift of the driving voltage occur, and the good display characteristics cannot be obtained and the color can be reproduced. The range was small and the display quality was unsuitable for a television image display device.

It is a figure which shows the frequency characteristic of the dielectric loss tangent of a red pixel colored layer material. It is a figure which shows the frequency characteristic of the dielectric loss tangent of a green pixel colored layer material. It is a figure which shows the frequency characteristic of the dielectric loss tangent of a blue pixel colored layer material. It is a figure which shows the relative spectral radiance of the LED backlight used for the Example and comparative example of this invention. It is a figure which shows the relative spectral radiance of the CCFL backlight used for the comparative example of this invention.

Claims (5)

In a color filter used for a liquid crystal display device having a white backlight in which red LED, green LED and blue LED are combined and a color filter having a colored layer of at least red, green and blue pixels,
The colored layer forming the green pixel includes Pigment Green 36, the content of Pigment Green 36 is 18% by weight or less, and the dielectric loss tangent (tan δ) of the colored layer forming the green pixel is a liquid crystal display. A color filter having a driving frequency of the apparatus and the vicinity thereof of 0.03 or less. In a color filter used for a liquid crystal display device having a white backlight in which red LED, green LED and blue LED are combined and a color filter having a colored layer of at least red, green and blue pixels,
The emission peak wavelength of the green LED of the white backlight is 500 to 540 nm, and the color reproducible range in the xy chromaticity diagram which is the CIE1931 XYZ color system is 72% or more in NTSC ratio. The color filter according to 1.   3. The color filter according to claim 1, further comprising a protective layer made of a transparent resin on the colored layer.   A liquid crystal display device comprising the color filter according to claim 1.   A lateral electric field type liquid crystal display device comprising the color filter according to claim 1.

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