JP2008256819A - Color filter for liquid crystal display device and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter capable of displaying safety colors of JIS in a liquid crystal display device using three independent light emitting diodes, and to provide the liquid crystal display device. <P>SOLUTION: The color filter is composed of colored pixels of red (R), green (G), blue (B) and yellow (Y), wherein transmittances at 600 nm and 650 nm of red are respectively 55 to 90% and 80 to 98%, respectively; transmittances at 450 nm, 525 nm and 650 nm of green are 58% or less, 15 to 93% and 10% or less, respectively; transmittances at 450 nm and 600 nm of blue are respectively 28 to 93% and 20%, respectively; and transmittances at 500 nm and 650 nm of yellow are respectively 23% or less and 90 to 98%, respectively. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a matrix type liquid crystal display device, and in particular, a color for a liquid crystal display device capable of displaying a safety color defined in JIS-Z9103-1995 when three independent LEDs are used as a light source. The present invention relates to a filter and a liquid crystal display device.

  Since the liquid crystal display device is not a self-luminous display device, the display needs light from the other, for example, a backlight is provided behind the display, and the display is performed by the light from the back. In such a transmissive liquid crystal display device, white light from a backlight provided behind the transmissive liquid crystal display device passes through a color filter to become colored light and is emitted outside the front of the liquid crystal display device to be viewed. It has become.

  In the segment type liquid crystal display device used in a digital display instrument or the like, the color display of the direct transmission type liquid crystal display device corresponds to, for example, a segment electrode outside the liquid crystal display element as an optical shutter. Color display is performed by providing a color filter pattern of a specific color in the shape and displaying the shape of each segment portion in each specific color. The chromaticity and brightness of each specific color displayed by the segment type liquid crystal display device are substantially determined by the emission spectrum of the backlight, the spectral transmittance of the color filter of the specific color, and the electro-optical characteristics of the liquid crystal.

  Further, in a matrix type liquid crystal display device widely used for notebook PCs, color TVs, and the like, a large number of pixel electrodes are regularly arranged in the horizontal and vertical directions so that arbitrary characters and images can be displayed. In addition, corresponding to this pixel electrode, red (R), green (G), and blue (B) color filter pixels, which are the three primary colors of light, are regularly provided inside the liquid crystal display element to provide a full color display. Is going.

If this pixel is sufficiently subdivided, it will not be recognized as each color of red (R), green (G), and blue (B) because it will exceed the resolution of the eye if it is separated by a certain distance or more. , Recognized as a mixed color.
That is, in a matrix-type liquid crystal display device, an intermediate color of an arbitrary character or image is displayed by spatially mixing three pixels of red (R), green (G), and blue (B). is doing. Color display is performed by so-called juxtaposed additive color mixing.

In this matrix type liquid crystal display device, a white light source is generally used as a backlight as a light source. The liquid crystal display element functions as an achromatic black and white shutter, and by electrically controlling the degree of opening and closing of the black and white shutter of each pixel, the transmitted light amount of each pixel is changed to express a halftone, and a full color display Is going.
The color gamut, brightness, color temperature at the time of white display, etc. of this matrix type liquid crystal display device are the emission spectrum of the backlight, and the spectral transmittance of the color filters of red (R), green (G), and blue (B). , And the electro-optical characteristics of the liquid crystal.

CCFL (Cold Cathode Fluorescent Lamp), which is excellent in color rendering, is widely used as the light source of the backlight, and a pigment dispersion type color filter excellent in heat resistance, light resistance, etc. is used as the color filter. Widely used.
In recent years, the brightness of blue emitting LEDs (Light Emitting Diodes) has been greatly improved, and instead of CCFLs, LEDs with excellent color rendering and high saturation have begun to be used as the light source of the backlight of liquid crystal display devices.
This LED also has advantages such as low power consumption, light weight, and small size. For example, a blue light emitting LED and a yellow light emitting phosphor are combined as a backlight light source of a liquid crystal display device for a mobile phone. Types of pseudo-white LEDs are in practical use.

Table 2 shows the chromaticity coordinates of the reference color related to transmitted light among the safety colors specified in JIS-Z9103-1995, and Table 3 shows the product using the reference color. The range of the chromaticity coordinate which accept | permits the color at the time of manufacturing this is represented.
FIG. 1 shows the chromaticity coordinates of the reference color of red and the range of chromaticity coordinates on the chromaticity diagram using red as an example of the corresponding color types.

安全色とは、安全標識や安全表示に使用する際に、安全に関する意味が明確に与えられている有彩色のことである。安全標識は、文字、図形、記号、イラストの組み合わせによって安全を表現した平面板であり、この安全色を用いることによって、安全に関する警告、指示、及び情報が一目で分かるようにしたものである。

The safety color is a chromatic color that clearly gives a safety meaning when used for safety signs and safety indications. A safety sign is a flat plate that expresses safety by a combination of characters, figures, symbols, and illustrations. By using this safety color, warnings, instructions, and information related to safety can be understood at a glance.

  When such a safe color is to be displayed by a transmissive liquid crystal display device, the segment type liquid crystal display device uses, for example, a CCFL or a pseudo white LED as a backlight, and the shape of the segment is changed. Each color (color type, total 6 colors) shown in Table 2 is obtained by using a color filter in which a specific color of the segment is set to a safe color so as to display the safe color in the above characters, figures, etc. ) Can be displayed easily.

  However, in the matrix type liquid crystal display device, pixels of three primary colors of red (R), green (G), and blue (B) that are regularly arranged are used instead of specific colors that can be arbitrarily set. Since the characters, graphics, and the like are displayed, it is difficult to display and display all six safety colors in the color reproduction range.

FIG. 2 shows an emission spectrum of an example of a pseudo white LED that is practically used as a light source of a backlight of a liquid crystal display device. InGaN is mainly used as a material of the blue LED constituting the pseudo white LED, and YAG (Itium Aluminum Garnet) is used as a material of the yellow phosphor.
In this pseudo white LED, a phosphor is applied to a blue LED, the phosphor is excited with blue light to form yellow light, and white light is obtained by mixing the yellow light and the blue light.

  As shown in FIG. 2, this pseudo-white LED has a main wavelength of blue light emission near a wavelength of 470 nm and a main wavelength of yellow light emission near a wavelength of 570 nm, and white color is obtained by this color mixture. The chromaticity coordinates of this pseudo white LED are Wx = 0.305, Wy = 0.308, and the color temperature is about 7200K.

  FIG. 3 shows a spectral transmittance of an example of a pigment dispersion type color filter used as a color filter for a liquid crystal display device. The pigment dispersion type color filter shown as an example has a preferable performance when displaying a safe color.

  As shown in FIG. 3, the red pixel constituting the color filter for a liquid crystal display device has a transmittance of about 85% at a wavelength of 600 nm and a transmittance of about 88% at a wavelength of 650 nm, and the green pixel transmits at a wavelength of 450 nm. The transmittance is about 1%, the transmittance is about 85% at a wavelength of 525 nm, the transmittance is about 3% at a wavelength of 650 nm, and the blue pixel has a transmittance of about 85% at a wavelength of 450 nm and the transmittance is about 0% at a wavelength of 600 nm. It is.

図２に示す疑似白色ＬＥＤをバックライトの光源とし、図３に示す液晶表示装置用カラーフィルタを色再現のカラーフィルタとして用いた液晶表示装置の性能は、表４に示すようなものとなる。
すなわち、図１に、表４中の赤の色度座標（ｘ：０．６１４、ｙ：０．３４９）を△印にて例示するように、前記ＪＩＳ−Ｚ９１０３で規定される安全色の色度座標の範囲内にはない。
特開２００５−１３４５０８号公報 ＪＩＳ−Ｚ９１０３−１９９５

The performance of the liquid crystal display device using the pseudo white LED shown in FIG. 2 as the light source of the backlight and the color filter for the liquid crystal display device shown in FIG. 3 as the color filter for color reproduction is as shown in Table 4.
That is, in FIG. 1, the color of the safety color defined in the JIS-Z9103 is exemplified by the Δ chromaticity coordinates (x: 0.614, y: 0.349) in Table 4. It is not within the range of degree coordinates.
JP 2005-134508 A JIS-Z9103-1995

The present invention has been made in view of the above problems. In a matrix type liquid crystal display device using three independent LEDs as a light source of a backlight, all six colors of safety colors defined in JIS-Z9103-1995 are provided. It is an object of the present invention to provide a color filter for a liquid crystal display device capable of displaying all.
Moreover, this invention makes it a subject to provide the liquid crystal display device which can display the said safe color.

  The present invention is a color filter for a liquid crystal display device composed of colored pixels of three primary colors, red (R), green (G), blue (B), and yellow (Y), and the red pixel has a wavelength of 600 nm. The transmittance is 55% to 90%, the transmittance at a wavelength of 650 nm is 80% to 98%, the transmittance of a green pixel at a wavelength of 450 nm is 58% or less, the transmittance at a wavelength of 525 nm is 15% to 93%, and The transmittance at a wavelength of 650 nm is 10% or less, the transmittance of a blue pixel at a wavelength of 450 nm is 28% to 93%, the transmittance at a wavelength of 600 nm is 20% or less, and the transmittance of a yellow pixel at a wavelength of 500 nm is 23. %, And the transmittance at a wavelength of 650 nm is 90% to 98%.

  According to another aspect of the present invention, there is provided a liquid crystal display device using three independent LEDs as a light source of a backlight and using the color filter for a liquid crystal display device according to claim 1 as a color filter for color reproduction.

  According to a second aspect of the present invention, there is provided the liquid crystal display device according to the second aspect, wherein each safety color within a range of chromaticity coordinates shown in Table 5 below is displayed.

  In the present invention, the transmittance of a red pixel at a wavelength of 600 nm is 55% to 90%, the transmittance at a wavelength of 650 nm is 80% to 98%, the transmittance of a green pixel at a wavelength of 450 nm is 58% or less, and the wavelength is 525 nm. The transmittance is 15% to 93%, the transmittance at a wavelength of 650 nm is 10% or less, the transmittance of a blue pixel at a wavelength of 450 nm is 28% to 93%, and the transmittance at a wavelength of 600 nm is 20% or less, Since it is a color filter for a liquid crystal display device in which the transmittance of a yellow pixel at a wavelength of 500 nm is 23% or less and the transmittance at a wavelength of 650 nm is 90% to 98%, a matrix type using three independent LEDs as a light source of a backlight In the liquid crystal display device, all 6 colors of safety colors specified in JIS-Z9103-1995 are displayed. Capable of displaying a hand becomes a color filter for a liquid crystal display device.

  Further, since the present invention is a liquid crystal display device using three independent LEDs as a light source of a backlight and using the above color filter for a liquid crystal display device as a color filter for color reproduction, the safety defined in JIS-Z9103-1995 is provided. The liquid crystal display device can display all six colors.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 4 shows the spectral transmittance of one embodiment of the color filter for a liquid crystal display device according to the present invention.
As shown in FIG. 4, the transmittance at a wavelength of 600 nm of a red pixel constituting the color filter for a liquid crystal display device is about 87%, the transmittance at a wavelength of 650 nm is about 93%, and the transmission of a green pixel at a wavelength of 450 nm. The transmittance at a wavelength of 525 nm is approximately 72%, the transmittance at a wavelength of 650 nm is approximately 0%, the transmittance of a blue pixel at a wavelength of 450 nm is approximately 65%, and the transmittance at a wavelength of 600 nm is 0. The transmittance of the yellow pixel at a wavelength of 500 nm is about 8%, and the transmittance at a wavelength of 650 nm is about 96%.

Such a color filter for a liquid crystal display device has, as a basic composition, the pigment composition of each color photoresist used when forming red, green, and blue pixels having the spectral transmittance shown in FIG. In order to realize the spectral transmittance, it can be obtained by adjusting the composition ratio in the basic composition or changing to a preferable pigment.
In the red pixel, when preparing a pigment-dispersed red photoresist used to form the red pixel, the composition ratio of several types of red pigment and yellow pigment used is adjusted to improve the color purity of the red pixel, The yellowness is reduced.

In addition, when preparing a pigment-dispersed green photoresist used to form a green pixel, the color purity of the green pixel was improved and the yellow color was reduced by changing to a preferred pigment. It is supposed to be.
Further, in the blue pixel, when preparing a pigment dispersion type blue photoresist used for forming the blue pixel, the color purity as the blue pixel is improved by changing to a preferable pigment.
In the yellow pixel, the color purity of the yellow pixel is improved by changing to a preferable pigment when preparing a pigment-dispersed yellow photoresist used for forming the yellow pixel.

FIG. 5 shows an emission spectrum of an example of the three independent LEDs in the present invention. As shown in FIG. 5, the three independent LEDs have the main wavelengths of the respective LEDs around a wavelength of 445 nm, a wavelength of 540 nm, and a wavelength of 640 nm.
The performance of the liquid crystal display device using the three independent LEDs shown in FIG. 5 as the light source of the backlight and the color filter for the liquid crystal display device shown in FIG. 4 as the color filter for color reproduction is as shown in Table 6.
That is, in FIG. 1, the color of the safety color defined in the JIS-Z9103 is exemplified by the x mark of the chromaticity coordinates (x: 0.627, y: 0.335) of red in Table 6. This is a color filter for a liquid crystal display device that is within the range of degree coordinates and can display all six safety colors.

  Examples of the 3 independent LEDs used in the present invention include 3 independent LEDs having an emission spectrum shown in FIG.

Among the safety colors defined in JIS, the chromaticity coordinates of the reference color of red and the range of chromaticity coordinates are represented on a chromaticity diagram. 2 shows an emission spectrum of an example of a pseudo white LED that is practically used as a light source of a backlight of a liquid crystal display device. The spectral transmittance of an example of a pigment dispersion type color filter is shown. FIG. 5 shows the spectral transmittance of an embodiment of a color filter for a liquid crystal display device according to the present invention. FIG. The emission spectrum of an example of 3 independent LED in this invention is shown.

Explanation of symbols

R: Spectral transmittance of red pixel G: Spectral transmittance of green pixel B: Spectral transmittance of blue pixel Y: Spectral transmittance of yellow pixel

Claims (3)

  A color filter for a liquid crystal display device composed of colored pixels of three primary colors, red (R), green (G), blue (B), and yellow (Y), and the transmittance of a red pixel at a wavelength of 600 nm is 55. % To 90%, transmittance at a wavelength of 650 nm is 80% to 98%, transmittance of a green pixel at a wavelength of 450 nm is 58% or less, transmittance at a wavelength of 525 nm is from 15% to 93%, and transmission at a wavelength of 650 nm The transmittance at a wavelength of 450 nm for a blue pixel is 28% to 93%, the transmittance at a wavelength of 600 nm is 20% or less, and the transmittance at a wavelength of 500 nm for a yellow pixel is 23% or less, and A color filter for a liquid crystal display device having a transmittance of 90% to 98% at a wavelength of 650 nm.   3. A liquid crystal display device using three independent LEDs as a light source of a backlight and using the color filter for a liquid crystal display device according to claim 1 as a color filter for color reproduction. 3. The liquid crystal display device according to claim 2, wherein each safety color within a range of chromaticity coordinates shown in Table 1 below is displayed.

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