JP5343185B2 - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter including a colored layer having colored parts of a plurality of colors repetitively aligned in order, which can provide a viewing angle extending function and reduce optical leak detectable by an observer in its combined use with a liquid crystal display device. <P>SOLUTION: The color filter includes a colored layer having colored parts of a plurality of colors aligned in order with at least one direction as a repeating direction, and a birefringent function layer having polymerizable liquid crystal molecules fixed thereto while being oriented in a desired direction, which are laminated directly or indirectly on a translucent substrate in this order. The colored layer includes a colored part of a color in which an outline shape of a vertical section cut in the repeating direction is substantially bilaterally symmetric and a colored part of a color in which the outline shape is substantially bilaterally asymmetric, and the color of the bilaterally asymmetric colored part is a color which has the lowest luminance when the color filter is bright-displayed for each of the plurality of colors. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

The present invention uses a color filter that colors visible light that passes through red (R), green (G), blue (B), cyan (C), magenta (M), yellow (Y), and the like. The present invention relates to a liquid crystal display device provided as a display-side substrate .

  At present, liquid crystal display devices capable of color display (color liquid crystal display devices) are widely used. On the viewer side of a general color liquid crystal display device, a color filter in which colored portions corresponding to pixels (dots) are finely patterned is provided as a display side substrate, and a liquid crystal drive substrate including a liquid crystal drive electrode is provided. A liquid crystal cell is formed by sandwiching driving liquid crystal molecules between them, and this is switched for each pixel to switch between bright display (white display) and dark display (black display). In a typical color filter, colored portions of three colors corresponding to the three primary colors of red (R), green (G), and blue (B) are repeatedly arranged side by side in stripes at each pixel width. A transparent colored layer is formed. Three pixels (dots) of R, G, and B constitute one picture element (pixel), and each picture element can perform color display by the additive color mixing method.

Further, in addition to the RGB additive color mixing method, by arranging three colored portions of cyan (C), magenta (M), and yellow (Y), color display by the subtractive color mixing method becomes possible.
In addition to the repeated arrangement of the colored portions in the stripe form in the horizontal direction as described above, the colored layer may be patterned in a matrix in two vertical and horizontal directions or in two oblique directions.
Furthermore, in recent years, in order to express more complex colors, a color filter including four colored portions in which complementary colors such as yellow and cyan are added in addition to red, green, and blue has been proposed.

  The colored portions of the plurality of colors are colored materials of each color at a high resolution using a photolithographic method directly on a light-transmitting substrate or indirectly through a light-shielding black matrix or other underlayer. In general, the coatings are arranged in a stripe shape or a matrix shape. When coating and forming three colored portions in a repeating direction, repeating three times of photolithography while changing the color of the coloring material, repeating four times of photolithography when forming four colored portions side by side Will be repeated.

  In recent years, a color filter used in a liquid crystal display device or the like has been developed that includes a birefringence functional layer between substrates in order to expand a viewing angle (for example, Patent Document 1 below). Such color filters are fixed in a state in which liquid crystal ink is applied directly on the colored layer or indirectly through another layer such as an alignment film, and the polymerizable liquid crystal molecules contained therein are aligned in a desired direction. A birefringence functional layer (in-cell phase difference layer) formed. For example, an in-cell retardation layer in which polymerizable liquid crystal molecules are vertically aligned with respect to a color filter is a positive electrode that compensates for the viewing angle of a polarizing plate arranged in a crossed Nicols state on the forefront side and the back side of the liquid crystal display device. While functioning as a C plate, it can also serve as a protective layer that physically protects the colored layer. In addition, as the in-cell retardation layer, a positive A plate, a negative C plate, a hybrid alignment plate, and the like in which polymerizable liquid crystal molecules are fixed to each other in a horizontal alignment state have been proposed. Further, since the in-cell retardation layer is sandwiched between the display side substrate and the liquid crystal driving substrate (in-cell side) together with the driving liquid crystal molecules, there is an advantage that the in-cell retardation layer is physically protected and hardly absorbs moisture.

JP 2004-240102 A

  However, in recent years, there has been a demand for higher brightness and higher quality of liquid crystal displays, and in-cell phase difference type color filters in which colored portions are formed with a high resolution by a photolithography method are also required to block visible light. The problem of light leakage, which is known to the observer due to a slight amount of transmitted light during display, has been recognized as a problem to be improved. Especially when the protective layer that has been generally provided between the color filter and the driving liquid crystal molecules is omitted in order to realize a thin liquid crystal display device, and this is also used in the in-cell retardation layer, The above light leakage problem occurred remarkably.

  Therefore, the present inventor has studied in detail the cause of the light leakage of the color filter. As a result, it has been found that light leakage may occur only for a specific color among a plurality of colored portions constituting the colored layer of the color filter. This light leakage at the specific colored portion is a cause of light leakage that has been conventionally considered to occur in the entire color filter.

The present invention has been made to solve the above problems, that is, when a color filter including a colored layer in which colored portions of a plurality of colors are repeatedly arranged in order is used in combination with a liquid crystal display device. An object of the present invention is to provide a liquid crystal display device having a color filter capable of obtaining a viewing angle expansion function and reducing light leakage obtained by an observer.

  In making the present invention, the present inventor diligently investigated the cause of the above problems, and as a result, the three-color colored layer formed by repeating the three photolithography steps was applied the second time. In the colored part (second colored part), more specifically, on the side adjacent to the colored part (first colored part) applied and formed for the first time among the colored parts of the second color, the liquid crystal display device It was found that light leaks from. In addition, regarding the four-color colored layer that is made by repeating the photolithography process four times, the colored portion applied the second time (second color) and the colored portion applied the third time (third color) In the color), it has been found that light leakage occurs on the side adjacent to the colored portion (the colored portion of the first color or the second color, respectively) formed by coating in the immediately preceding process. Then, when the outer shape of the vertical cross section obtained by cutting the colored portion of each color in its repeating direction (hereinafter sometimes referred to as the width direction) is measured with a three-dimensional measuring instrument, the colored portion where the light leakage occurs is as follows. It was found that this was a left-right asymmetric shape inclined in one direction.

FIG. 7 is a schematic diagram regarding a vertical cross section of the colored layer 11 formed in the conventional color filter, and corresponds to the measurement result by the three-dimensional measuring device. In the drawing, the dimension in the thickness (vertical direction in the figure) direction is enlarged with respect to an actual colored layer. The horizontal direction in the figure is the repeating direction of the colored portion. In addition, the figure also shows a state in which the liquid crystal molecules 50 applied on the colored layer 11 are vertically aligned. The colored portion 12 (R) of the first color is red, the colored portion (G) of the second color is green, and the colored portion 12 (B) of the third color is blue. These are R (red) by photolithography. ) G (green) B (blue) in the order of coating side by side.
That is, in the conventional color filter, the red colored portion 12 (R) is formed by the first photolithography process, the green colored portion 12 (G) is adjacent to red by the second photolithography process, and the third time. In general, a blue colored portion 12 (B) is repeatedly applied every two rows on the base material 16 between green and red by a photolithography process.
In the figure, each colored portion has a stripe shape extending in the front-rear direction of the paper surface, and represents a state in which the boundary between each colored portion is partitioned by a black matrix (BM) 14. The width of the light transmissive region opened between the adjacent BMs 14 corresponds to the pixel width of the liquid crystal display device.

In the colored layer 11, when the in-cell retardation layer is fixedly formed by applying the polymerizable liquid crystal molecules 50 directly on the upper surface or indirectly through an alignment film (not shown), For the three colored portions 12 (R) and 12 (B), the alignment of the liquid crystal molecules 50 existing on the colored layer interface side is bilaterally symmetric (Sy), and the liquid crystal molecules 50 located above the liquid crystal molecules 50 are also continuous elastic body theory. Based on the vertical alignment.
The outer portions of the colored portions 12 (R) and 12 (B) are formed with convex portions 22 and 23 having the same height at both ends in the width direction by riding on the BM 14 and the adjacent colored portion, and the center is flat. It has a symmetrical shape. For this reason, although the vertical alignment of the liquid crystal molecules 50 is tilted to the inside of the pixel in the vicinity of the convex portions 22 and 23, the alignment of the liquid crystal molecules 50 on the color layer interface side balances left and right when averaged in units of pixels. An alignment defect does not occur in the liquid crystal molecules 50 above the interface.

On the other hand, the second color portion 12 (G) has different heights at both ends in the width direction, and the right side of the drawing, which is the side adjacent to the third color portion 12 (B), has liquid crystal molecules 50. Although there is a region where the orientation is balanced to the left and right (Sy), the liquid crystal molecules 50 are tilted in one direction (in the case of FIG. The liquid crystal molecules 50 existing thereabove are also asymmetric (Asy), resulting in poor alignment. For this reason, a desired phase difference cannot be obtained in the transmitted light in the formed in-cell retardation layer, and light leakage occurs during dark display.
Further, scattering of transmitted light (scatter) caused by such poor alignment causes a problem of light leakage during dark display.

The present inventor has further studied, a mechanism in which such orientation failure occurs only in the second color coloring portion in the three-color filter and only in the second and third color coloring portions in the four-color filter. I found it. A typical manufacturing method of the conventional three-color filter and the above mechanism will be described with reference to schematic diagrams in FIGS.
FIG. 2A is a schematic diagram showing the first photolithography process. The light is applied to the entire surface of the base material 16 (only the upper surface is shown in the figure (b) and below) on which the BM 14 is optionally formed in a stripe shape or a matrix shape with a pixel width therebetween or to cover the effective display area. A first color coloring material 18 (R), which is a curable coloring resist material, is applied. In addition, as shown in the figure, a photomask 20 having a mask opening 21 formed corresponding to the planned formation position of the colored portion 12 (R) of the first color is placed facing the substrate 16, and the photomask 20 is Actinic radiation such as ultraviolet rays is exposed to the coloring material 18 (R) through. Only the portion of the coloring material 18 (R) that has ridden on the BM 14 bulges. In general, the colored portion 12 is formed thicker than the BM 14. In addition, the bulging does not occur when the BM 14 is not formed on the upper surface of the base material 16.
FIG. 6B shows a state in which the unexposed portion is removed by etching the colored material 18 (R) after the exposure to leave the colored portion 12 (R) of the first color. In the colored portion 12 (R), convex portions 22 are formed at both ends in the width direction riding on the BM 14, and a flat portion 24 is formed at the center. In the case of a color filter not provided with the BM 14 as described above, the convex portion 22 does not occur and the colored portion 12 (R) is formed flat.

FIG. 4C is a schematic diagram showing the second photolithography process. That is, using the base material 16 including the colored portion 12 (R) of the first color obtained above as an underlayer, the colored material 18 (G) of the second color, which is a colored resist material, is applied to the entire surface, and the second A state in which ultraviolet exposure is performed through a photomask 20 in which a mask opening 21 is formed facing a predetermined formation position of the colored portion 12 (G), that is, a position adjacent to the first colored portion 12 (R). Is shown. The coloring material 18 (G) bulges out at the portion that rides on the BM 14 and the coloring portion 12 (R).
FIG. 4D shows a state in which the coloring material 18 (G) is etched and the second colored portion 12 (G) remains. The colored portion 12 (G) is formed adjacent to one side (right side in the figure) with respect to the colored portion 12 (R) of the first color, and the side adjacent to the colored portion 12 (R) ( The higher convex part 23 is formed on the left side in the figure, and the lower convex part 22 is formed on the opposite side. In addition, the outer shape of the cross section of the colored portion 12 (G) is formed with an inclined portion 25 that descends from the left to the right in the drawing in the center of the width. This is because the colored layer 12 (R) is already thick only on one side (left side in the figure) of the width direction of the pixel in the base layer to which the coloring material 18 (G) of the second color is applied. The other side (the right side in the figure) is only provided with a thin BM 14, and the applied height of the applied coloring material 18 (G) is adjacent to the colored portion 12 (R). This is because it becomes higher on the side to be performed.

FIG. 4E is a schematic diagram showing the third photolithography process. That is, the third color coloring material 18 (B), which is a colored resist material, is applied to the entire surface of the base material 16 including the colored portions 12 (R) and 12 (G) of the first color and the second color, A state is shown in which the mask opening 21 is opposed to an unformed region of the colored portions 12 (R) and 12 (G) and ultraviolet exposure is performed. Convex resulting from riding on the BM 14 at both ends of the colored portions 12 (G) and 12 (R) that are already fixedly formed adjacent to the left and right of the planned formation position of the colored portion 12 (B). The part 22 is formed at the same height.
FIG. 5F shows a state in which the coloring material 18 (B) is etched to leave the third color portion 12 (B) remaining. At both ends of the colored portion 12 (B), a high convex portion 23 resulting from riding on the adjacent colored portion is formed at the same height as the left side of the colored portion 12 (G). Thus, the colored layer 11 including the first to third colored portions 12 (R), 12 (G), and 12 (B) is formed.

  As described above, for the first color coloring portion 12 (R) and the third color coloring portion 12 (B), the state of the base layer in the UV-cured region is the same on both sides in the width direction of the pixel. Therefore, even when the convex portions 22 and 23 are formed at both ends, the height of the outer shape is the same on the left and right sides, and the flat portion 24 is formed at the center of the width, resulting in a left-right symmetrical shape. . On the other hand, for the colored portion 12 (G) of the second color, the colored portion 12 (R) is already cured and formed on one side in the width direction of the planned formation region, and this does not exist on the other side. The outer shape is inclined downward from the one side toward the other side to become a left-right asymmetric shape.

  The principle that light leakage occurs in the second and third color portions in the four-color filter in which the four color portions are arranged adjacently in the width direction is the same as described above. That is, the colored layer of the other color (first color) is formed in advance only on one side in the width direction on the base layer to which the coloring material of the second color is applied, and the coloring material of the third color is applied. Since the colored layer (second color) of other colors is also formed in advance only on one side in the width direction in the base layer, the colored portions of these colors are asymmetric in the outer shape. On the other hand, for the first color and the fourth color, the colored layer of the other color is not formed in advance in the undercoat layer to which these are applied (first color), or other colors are already present on both sides in the width direction. Since the colored portion is formed (fourth color), the outer shape is symmetrical. For this reason, in the colored portion of the second color and the third color, it was applied to produce an in-cell retardation layer on the side adjacent to the other colored portion previously formed only on one side in the width direction. An alignment defect of the liquid crystal molecules 50 occurs, which causes a light leakage due to an abnormal phase difference or scatter in the transmitted light.

Specifically, the present invention for reducing the light leakage caused by the mechanism described above allows the observer even when the colored portion of any one of a plurality of colors has an asymmetrical outer shape due to the above reasons. This is based on the technical idea that a known color with the least light leakage is selected and applied to the left-right asymmetric pixel.
Here, the contrast ratio, which is one of the important indicators of the display quality of the liquid crystal display device, is obtained by dividing the brightness during bright display (bright field brightness) by the brightness during dark display (dark field brightness). The contrast ratio can be increased by improving the luminance during display or reducing the luminance during dark display. The color filter of the present invention is intended to obtain a high contrast ratio by preventing light leakage when all colors are darkly displayed (during black display) and reducing dark field luminance. When selecting a color with the least amount of light leakage occurring during dark display and applying it to the left and right asymmetric pixels, a determination is made based on the bright field luminance that allows a large amount of transmitted light and accurate luminance measurement. The color with the lowest bright field luminance observed when each color is individually turned on (bright display) is assigned to a colored portion having a laterally asymmetric outer shape.

That is, a liquid crystal display device comprising the color filter according to the present invention is
(1) A liquid crystal display device in which a color filter, a driving liquid crystal layer including driving liquid crystal molecules, a liquid crystal driving substrate including a liquid crystal driving electrode, and a backlight device are arranged in this order from the viewer side. ,
The color filter is directly or indirectly on a light-transmitting substrate, and a colored layer in which a plurality of colored portions of four or more colors are sequentially arranged with at least one direction as a repeating direction, and polymerizable liquid crystal molecules A color filter formed by laminating a birefringence functional layer fixed in a state oriented in a desired direction in this order ,
The colored layer is composed of a colored portion whose color is substantially symmetrical in the outer shape of a vertical section cut in the repeating direction, and a colored portion whose color is substantially asymmetric in the outer shape,
The color of the left-right asymmetric coloring part is two or more colors,
The two or more colors are colors having the highest luminance when the color filter is subjected to bright display for each of the plurality of colors according to the radiation intensity of the main wavelength of the backlight light in the backlight device. A color that does n’t match is selected,
In addition, for the two or more colors, the luminance is lowest when the color filter is subjected to bright display for each of the plurality of colors in accordance with the emission intensity of the main wavelength of the backlight light in the backlight device. A liquid crystal display device comprising a color ;
(2 ) The backlight light in the backlight device is white visible light, and the plurality of colors include red, blue, and green, and the two or more colors include blue (1) ) Liquid crystal display device according to
( 3 ) The liquid crystal display device according to (1) or (2), wherein the polymerizable liquid crystal molecules are homeotropically aligned ;
Is the gist.

In the present invention, the outline shape of the cross section in the width direction of the colored portion is “substantially bilaterally symmetric”, specifically, directly above the colored portion or indirectly via another layer such as an alignment film. When the polymerizable liquid crystal molecules are arranged in a state where the tilt is not biased in one direction to the extent that alignment defects are caused in the liquid crystal molecules in the effective display area and the position exposed from the light shielding area such as the black matrix. Means. As a preferable example of such a state, in addition to the case where the entire outer shape of the colored portion is flat, even when the outer shape has a convex portion or an inclination, a flat portion is present at or near the width center of the outer shape. Including the case where it is formed.
More specifically, the gradient of the approximate curve obtained by sampling within a range of 35% from the width center to one side (70% on both sides) at predetermined intervals from the center of the width is included, and (a) the colored portion When the width (pixel width) of the pixel is 150 μm or less, the difference in height between both ends in the width direction is 2500 mm or less. (B) When the pixel width is 150 μm or more, the difference in height between both ends in the width direction is 1700 mm or less. In addition, the outer shape of the cross section in the width direction of the colored portion is said to be “substantially bilaterally symmetric”.
If it is not “substantially left-right symmetric”, the outer shape of the colored portion is “substantially left-right asymmetric”.
The sampling interval can be about 20 to 40 equally in the width direction within the range of 70% on both sides.
Further, the above-mentioned “the gradient of the approximate curve includes an opposite sign” excludes the case where the gradient in the range is only positive or negative except for the gradient of zero. That is, when the gradient is zero or only positive, or only zero or negative, and when the height difference between both ends is not less than the predetermined value, the outer shape of the colored portion is “substantially left-right asymmetric” It is.
A commercially available three-dimensional measuring instrument such as a fine shape measuring instrument ET4000L (manufactured by Kosaka Laboratory Ltd.) can be used for measuring the outer shape of the colored portion.
In addition, since the alignment defect of the liquid crystal molecules within the pixel width becomes more prominent as the pixel width becomes larger, in the present invention, the allowable value of the height difference at both ends in the case of (b) is set as in the case of (a). It is more severe than that.

In the constituent layers constituting the color filter used in the present invention (hereinafter sometimes simply referred to as “color filter of the present invention”) , “upper”, “upper”, “upper surface”, or “lower”, “lower” The vertical direction such as “lower surface” means the relative positional relationship of the layers constituting the color filter such as the base material and the colored layer, and does not mean the vertical direction with respect to the direction of gravity.

  In the present invention, the “effective display area” means an area where transmitted light is emitted / incident and a predetermined display or observation is performed. For example, when the present invention is used in a liquid crystal display device, an image in the device is displayed. It means the area corresponding to the display area.

  The color filter of the present invention has a birefringence function by matching a color whose outer shape is substantially asymmetrical among the colored portions of the plurality of colors constituting the same with a color having the lowest luminance during bright display. Even if the liquid crystal molecules that make up the layer cause alignment failure due to the lateral shape of the colored portion that is the underlying layer being asymmetrical, the observer will be able to perform dark display with the color filter. It is possible to satisfactorily suppress light leakage perceived by the camera.

Here, the specific luminous sensitivity (luminous luminous sensitivity) of visible light is higher in the order of green (main wavelength = 550 nm)> red (main wavelength = 630 nm)> blue (main wavelength = 450 nm), and the luminance is emission of leaking light. When the visible light incident on the colored layer is white light with the same radiant intensity for each dominant wavelength, the color to be applied to the colored part where the outer shape is asymmetrical is blue. By doing so, the luminance of light leakage perceived by the observer can be reduced most.
For example, in a liquid crystal display device in which the color filter of the present invention is sandwiched between polarizing plates in a crossed Nicol state together with a liquid crystal cell, in a region corresponding to a blue pixel in a birefringence functional layer fixedly formed on the upper surface of a colored layer. When alignment failure occurs, the desired phase difference is not given to the transmitted light, and light scattering (scatter) occurs, and the traveling direction of the transmitted light is changed. It passes through the polarizing plate and reaches the viewer. However, since the leaked light is blue having the lowest specific visibility, it is perceived by the viewer as a light leak with low luminance. A contrast ratio can be obtained.
Thus, the color filter of the present invention has an in-cell type birefringence functional layer to provide a viewing angle widening function. Conventionally, in order to flatten the upper surface of the colored layer, the colored layer and the driving liquid crystal molecules The protective layer formed during coating can be replaced with a birefringent functional layer and can be omitted, and the leakage light perceived by the observer as described above can be reduced to provide a high-quality display. Can do.

[First embodiment]
FIG. 1 is a vertical cross-sectional schematic view in which the base material 16 and the colored layer 11 in the color filter 10 according to the first embodiment of the present invention are cut in the repeating direction of the colored portion 12. Vertically aligned liquid crystal molecules 50 are applied to the upper surface of the colored layer 11.
The colored portion 12 of the present embodiment is composed of three colors of R (red), G (green), and B (blue), and is fixed side by side in the order of red → blue → green by a photolithography method. .
Specifically, the BMs 14 are arranged in a stripe shape or a lattice shape at a pitch corresponding to the pixel width on the light transmissive base material 16, and the colored portions 12 (R), 12 ( B) and 12 (G) are fixedly formed in order and colored in each color. Then, three adjacent colored portions 12 are combined to form one picture element. When the color filter 10 is used in a liquid crystal television which is an example of a color display device, the width of each picture element is on the order of several tens to several hundreds of μm. In addition, when the color filter 10 is used for a mobile device screen such as a mobile phone that requires finer color display, the pixel and pixel are generally narrower than this.

In the color filter 10 of the present embodiment, red and green are selected as the coloring materials applied to the first and third colors, and blue is selected as the coloring material applied to the second color. Note that it is arbitrary which one of the first and third colors is red or green.
The first colored portion 12 (R) is formed with relatively low convex portions 22 at both ends in the width direction, and the third color portion 12 (G) is relatively high at both ends in the width direction. The convex portions 23 are formed equally and the outer shape is substantially symmetrical. On the other hand, the colored portion 12 (B) of the second color has a convex portion 23 at one end in the width direction and a convex portion 22 at the other end, so that the outer shape is substantially asymmetric.

  By selecting the first to third colors as described above, in the colored layer 11 fixedly formed three times by the photolithography method, the colored portions of the first and third colors (colored portions 12 (R), 12 In (G)), the orientation of the liquid crystal molecules 50 applied thereon is symmetrical in the width direction within the pixel, whereas in the second colored portion (colored portion 12 (B)), the liquid crystal molecules 50 are poorly aligned. Although there is a risk of the occurrence of light, pixels that cause light leakage during dark display due to such poor alignment are limited to blue. And since blue is the color with the lowest relative visibility among RGB, the luminance (dark field luminance) which is one of the psychophysical quantities felt by the observer during dark display is suppressed, and a color display device using the color filter 10 is used. A high contrast ratio is achieved.

In the present invention, when visible light incident on the colored layer 11 is other than white light, a coloring material other than blue may be selected as the second color. That is, for example, in the case where a backlight having a strong blue tint is combined as a light source of a liquid crystal display device in which the color filter 10 is used, the intensity of visible light that passes through the blue coloring portion 12 (B) is increased. In some cases, the dark field luminance is most suppressed by selecting red or green as the coloring material applied to.
That is, it suffices to select which color of the coloring material should be applied to the second color according to the radiation intensity of the main wavelength of the external light or the backlight light passing through the color filter 10. When making such a selection, as described above, the bright field luminance is measured from the product of the radiant intensity and the relative luminous sensitivity observed when each color is brightly displayed, and the lowest color is applied to the second color. Color can be used.

  2A to 2F are schematic views for explaining a plate making process of the colored layer 11 in the color filter 10 of the present embodiment. This figure corresponds to FIGS. 8A to 8F which are conventional plate making processes. In the color filter 10 of the present embodiment, it is assumed that white light is used as external light or backlight light, and the blue color having the lowest specific visual sensitivity among RGB and the lowest bright field luminance is assumed as the coloring material of the second color. Is selected. For convenience, the order of the coloring materials applied to the base material 16 in the present embodiment is red for the first color and green for the third color.

  As a first step, a red coloring material 18 (R), which is a coloring material of the first color, is applied directly on the light-transmitting substrate 16 or indirectly through another light-transmitting underlayer. Then, this is patterned by a photolithography method (FIG. (A)), and the colored portions 12 (R) of the first color are dispersed in the width direction (FIG. (B)). The red coloring material 18 (R) is applied to at least an area covering the effective display area, and the colored portion 12 (R) is formed in a two-pixel width interval.

  As a second step, a blue coloring material 18 (B) which is a coloring material of the second color is applied, and this is patterned by a photolithography method ((c) in the same figure), and the colored portion 12 (R of the first color) ), The blue colored portions 12 (B) are dispersed and formed at positions adjacent to each other in the width direction ((d) in the figure).

  As a third step, a green coloring material 18 (G) which is a coloring material of the third color is applied, and this is patterned by a photolithography method (FIG. (E)), and has already been formed on both sides in the width direction. The green colored portion 12 (G) is formed at a position adjacent to both the colored portions 12 (B) and 12 (R), and the colored layer 11 is made (FIG. (F)).

In the colored layer 11 made by the above process, the flat portion 24 is formed at the center in the width direction for the red colored portion 12 (R) of the first color and the green colored portion 12 (G) of the third color. As for the blue colored portion 12 (B) of the second color, the inclined portion 25 is formed at the center in the width direction.
The colored portions in the present invention may be three colors as in the present embodiment, or may be four colors or five colors or more. In this case, in addition to the first to third steps, a step of forming a colored portion of the fourth color or the fifth color is performed. In the case of a color filter having four or more colored portions (N colors), the color having the highest bright field luminance is assigned to the first or last color, and the second to N-1 colored portions are colored. It is better to apply a color that lowers the bright field luminance.
The color filter 10 having four colored portions will be described in a second embodiment described later.

FIG. 3 is a schematic cross-sectional view showing a laminated structure of the color filter 10 including the colored layer 11 made by the above process. On the upper surface of the colored layer 11, there is formed a birefringence functional layer 30 in which polymerizable liquid crystal molecules 50 are polymerized and fixed to each other in an aligned state.
Therefore, in obtaining the color filter 10 of the present embodiment, in addition to the first to third steps, as a fourth step, polymerization is performed directly on the colored layer 11 or indirectly through another layer such as an alignment film. The liquid crystal ink containing the polymerizable liquid crystal molecules 50 is applied to align the polymerizable liquid crystal molecules 50 in a desired direction.
Then, as the fifth step, the aligned polymerizable liquid crystal molecules 50 are polymerized to form the birefringence functional layer 30.

Through the above steps, the RGB three-color filter 10 of the present embodiment including the in-cell type birefringence functional layer 30 is obtained.
In addition, in the color filter 10 of the present embodiment, a horizontal alignment film 34 for aligning driving liquid crystal molecules constituting the liquid crystal cell is laminated on the upper surface of the birefringence functional layer 30.

  Hereinafter, a preferable material, a plate making process, etc. are demonstrated more concretely about each layer which comprises the color filter 10. FIG.

(About the base material)
The substrate 16 is preferably configured to have optical isotropy, and a glass substrate, a film, or the like having optical transparency can be arbitrarily used. In particular, when the color filter of the present invention is used in a liquid crystal display device, the base material is preferably alkali-free glass. The thickness of the substrate is, for example, about 5 μm to 3 mm depending on the application.

(About black matrix)
In the color filter of the present invention, when the BM 14 is formed, for example, a metal thin film having a light shielding property or light absorbing property such as a metal chromium thin film or a tungsten thin film is formed on the substrate in a rectangular lattice shape or stripe shape having a predetermined shape. Alternatively, it can be formed by patterning in a triangular lattice pattern or the like. Moreover, it is also possible to form by printing an organic material such as a black resin in a predetermined shape by a transfer method or the like.

  In the present invention, the formation of BM14 is optional. However, even if alignment failure occurs in the critical region between the colored portions due to the presence of BM14, the alignment failure region should be within the BM region in plan view. For example, it is preferable in that light transmitted through the poor alignment region is blocked and light leakage is reduced.

The manufacturing method example of BM14 will be described in more detail. After the prepared black matrix material is washed on the glass substrate according to a conventional method, it is applied to a thickness of 3.0 μm by spin coating, at 90 ° C. for 3 minutes. Pre-baking, exposure to a predetermined pattern (100 mJ / cm ² ), spray development using 0.05% KOH aqueous solution for 60 seconds, and post-baking at 200 ° C. for 30 minutes to produce a black matrix substrate Can do. Further, the black matrix forming step may be performed by etching a substrate on which metal chromium or the like is vapor-deposited on a transparent base material in advance.

(About coloring parts and coloring materials)
When three colored portions are provided as in the color filter 10 of the present embodiment, the additive colors red (R), green (G), and blue (B) are selected as described above, and yellow (Y) is selected. , Cyan (C), magenta (M), and other complementary colors can be appropriately selected and used. Hereinafter, the coloring materials for forming the red, blue, and green colored portions will be described.

(Red colored part)
The coating thickness in the wet state of the red coloring material 18 (R) forming the red coloring portion 12 (R) varies depending on the required color reproducibility and the composition of the coloring material, but in general, It is preferably in the range of 1 μm to 4 μm, and particularly preferably in the range of 1 μm to 3 μm. When the film thickness is thicker than the above range, for example, curing and patterning by photolithography method is not successful, and fine unevenness is generated on the colored portion surface, or the shape becomes reverse tapered, which is not preferable. If it is thinner than the above range, it is difficult to obtain the required high color purity, which is not preferable.

  The red colored portion formed in the present invention is generally composed of a red pigment, a yellow pigment, a binder, a dispersant, and other additives. The type of the binder varies depending on the method for producing the red colored portion. In the present invention, the red colored portion is formed by a photolithography method such as a pigment dispersion method, and the colored portion is fixedly formed with high resolution. Therefore, it is preferable. When a colored material is fixed by a negative photolithography method to obtain a colored portion, a UV curable resin is used as a binder resin.

  In addition, the said pigment may use what was surface-treated, such as a rosin process, an acidic group process, a basic process, and a pigment derivative process, as needed. In addition, as a dispersant necessary for dispersing the pigment, styrene / butylstyrene copolymer, long-chain polyaminoamide phosphate, polyamide, high molecular weight polycarboxylate, oleylamine acetate, tetraalkylammonium salt, oleic acid Sodium, oleic acid amino oleate, phosphate ester salt, alkylbenzene sulfonate, etc. can be mentioned. Such a dispersant can be contained in the range of 30 to 100 parts by weight with respect to 100 parts by weight of the pigment.

  As the UV curable resin, examples of the binder resin component include monomers having an acidic group such as (meth) acrylic acid, maleic anhydride, styrenesulfonic acid, styrene, α-methylstyrene, ethyl (meth) acrylate. And a copolymer obtained by copolymerizing a monomer such as (meth) acrylamide.

Moreover, you may add a photoinitiator as another additive, Specifically, a halomethylated triazine derivative, a halomethylated oxadiazole derivative, an imidazole derivative, a benzophenone derivative etc. are mentioned. These photopolymerization initiators are compounds capable of generating radicals that polymerize a polymerizable group of a photopolymerizable monomer with ultraviolet rays, and are used alone or in combination.
Furthermore, examples of the photopolymerizable monomer include isobutyl acrylate, t-butyl acrylate, stearyl acrylate, 2-methoxyethyl acrylate, and 3-methoxybutyl acrylate.

  Specific examples of the solvent used for the red coloring material include diisopropyl ether, n-pentane, diethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl 3-ethoxypropionate, diglyme, and butyl carbitol. And organic solvents such as

  In addition, various additives can be added to the red colored portion of the present embodiment as necessary, for example, a sensitizer, a coatability improver, a development improver, a crosslinking agent, a polymerization inhibitor, You may contain a plasticizer, a flame retardant, etc. In addition, about the addition of the various additives added to the said pigment, it is the same also about the other pigment mentioned later.

(Green colored part)
The coating thickness in the wet state of the green coloring material 18 (G) forming the green coloring portion 12 (G) is also in the range of 1 μm to 4 μm, preferably in the range of 1 μm to 3 μm, for the same reason as the red coloring portion. It is assumed to be inside.
The green coloring material is mainly composed of a binder resin such as a green pigment, a yellow pigment, and a UV curable resin, and a solvent.

(Blue colored part)
The coating thickness in the wet state of the blue coloring material 18 (B) forming the blue coloring portion 12 (B) is also in the range of 1 μm to 4 μm, preferably in the range of 1 μm to 3 μm, for the same reason as the red coloring portion. It is assumed to be inside. A purple pigment may be added to the blue coloring material in order to adjust the color tone.

  In the color filter 10 of the present invention, it is preferable that the coating thicknesses of the colored portions of the respective colors are the same, but it is not necessary to strictly match them. That is, in the case of the three-color filter, the colored portion of the third color is substantially symmetrical with respect to the outer shape by running equally over the colored portions of other colors that are already fixedly formed on both sides in the width direction. Therefore, it is preferable that the coating thicknesses of the colored portion of the first color and the colored portion of the second color are equal. However, even if the coating thickness of each color differs within a difference of, for example, about 0.5 μm or less due to restrictions on the control accuracy of the coating thickness of the coloring material, the colored portion of the third color is compared with both sides in the width direction. The tendency of the outer shape that the high convex part is formed, the flat part is formed at the center, and the center of the colored part of the second color shows the inclination biased in one direction is unchanged, and the colored part of the second color The above-mentioned problem that remarkable light leakage occurs commonly occurs.

(About birefringence functional layer)
The type of the birefringent functional layer that can be formed by designing the orientation direction of the polymerizable liquid crystal material constituting the birefringent functional layer 30 to a desired direction is fixed by aligning liquid crystal molecules vertically (homeotropic alignment). So that the optical axis of the liquid crystal molecules is in the normal direction of the birefringent functional layer and has an extraordinary ray refractive index larger than the ordinary ray refractive index in the normal direction of the birefringent functional layer. Is mentioned. In another aspect, the birefringence functional layer 30 has an extraordinary ray refractive index greater than the ordinary ray refractive index in the in-plane direction of the birefringence functional layer while the optical axis of the liquid crystal molecules is parallel to the birefringence functional layer. A so-called positive A plate may be used. Furthermore, by making the optical axis of the liquid crystal molecules parallel to the birefringence functional layer and adopting a cholesteric orientation having a spiral structure in the normal direction, the birefringence functional layer as a whole has an extraordinary ray refraction smaller than the ordinary refractive index. It may be a so-called negative C plate in which the rate is the normal direction of the birefringence functional layer. Furthermore, the discotic liquid crystal having negative birefringence anisotropy may be a negative A plate having its optical axis in the in-plane direction of the birefringence functional layer. Furthermore, the birefringent functional layer 30 may be oblique to the layer, or may be a hybrid alignment plate whose angle changes in a direction perpendicular to the layer.

  The birefringence functional layer 30 may be a layer formed of any one of the above-described positive or negative C plate, A plate, or hybrid alignment plate, but is a layer formed by combining these layers. May be. For example, the birefringence functional layer 30 may be configured by sequentially laminating a positive A plate and a positive C plate on the upper surface of the colored layer 11. Alternatively, a positive A plate may be first formed on the upper surface of the substrate 16, then the colored layer 11 described above may be formed, and a positive C plate may be further formed on the upper surface of the colored layer 11. A positive or negative C plate or A plate or a hybrid alignment plate that can be used as the birefringence functional layer 30 can be appropriately formed on the colored layer 11 by a conventionally known method.

  Specifically, in order to form the birefringence functional layer 30, first, a liquid crystal composition containing a polymerizable liquid crystal material is applied onto the base material 16, the colored layer 11, or the alignment film as an underlayer. To form a liquid crystal coating film. For the application of the liquid crystal composition, for example, gravure printing method, offset printing method, relief printing method, screen printing method, transfer printing method, electrostatic printing method, plateless printing method, gravure coating method, roll Coating methods such as coating methods, knife coating methods, air knife coating methods, bar coating methods, dip coating methods, kiss coating methods, spray coating methods, die coating methods, comma coating methods, ink jet methods, spin coating methods, slit coating methods, etc. Or a combination of these methods can be used as appropriate.

  Next, the solvent component is removed by drying under reduced pressure, and the polymerizable liquid crystal material contained in the liquid crystal coating film is oriented in a desired direction, and then irradiated with ultraviolet rays, electron beams, etc. A polymerizable liquid crystal material oriented in the direction of (3) can be three-dimensionally polymerized to form a birefringent functional layer. However, the method for forming the birefringent functional layer in the present invention is not limited to this, and is a conventionally known method, in which a polymerizable liquid crystal is polymerized and fixed in a desired direction on a substrate surface. Any method may be adopted as long as it can be performed.

  For example, when the liquid crystal coating film is to be the birefringent functional layer 30 having a function as a positive C plate, the polymerizable liquid crystal material in the liquid crystal coating film is homeotropically aligned to polymerize the polymerizable liquid crystal materials. Giving homeotropic alignment to a polymerizable liquid crystal material means that the liquid crystal coating film is heated using means such as heating with infrared rays, and the temperature of the liquid crystal coating film is changed to the polymerizable liquid crystal (liquid crystal molecule contained therein). ) Is a temperature at which the liquid crystal phase becomes a liquid crystal phase (liquid crystal phase temperature) or higher and a temperature at which the polymerizable liquid crystal becomes an isotropic phase (liquid phase).

In addition, polymerization (crosslinking polymerization) between polymerizable liquid crystal materials to which alignment is imparted in the liquid crystal coating film is performed by irradiating the surface of the liquid crystal coating film with light having a photosensitive wavelength of a photopolymerization initiator contained in the liquid crystal composition. You can proceed with. At this time, the wavelength of light applied to the liquid crystal coating film is appropriately selected according to the absorption wavelength of the liquid crystal composition, but is generally about 200 to 500 nm. The light applied to the liquid crystal coating film is not limited to monochromatic light, and may be light having a certain wavelength range including the photosensitive wavelength of the photopolymerization initiator. In addition, in making the liquid crystal coating film into the birefringent functional layer 30, the liquid crystal coating film is irradiated with light to advance the crosslinking polymerization reaction of the polymerizable liquid crystal material, and further, the liquid crystal coating film is baked using an oven or the like. May be performed. By performing such baking, the polymerization reaction of the polymerizable liquid crystal material contained in the birefringence functional layer 30 can be promoted.
As described above, the polymerizable liquid crystal material contained in the liquid crystal coating film is polymerized to form the birefringence functional layer 30 fixed in a state where the polymerizable liquid crystal material is oriented in a desired direction.

<About polymerizable liquid crystal materials>
As a liquid crystal material for constituting the birefringence functional layer 30, a nematic liquid crystal having a rod-like structure is used as a liquid crystal material having a positive birefringence anisotropy, and a liquid crystal material having a negative birefringence anisotropy is used. Can use a discotic liquid crystal having a disk-like structure. These liquid crystal materials include liquid crystal monomers, liquid crystal oligomers, or liquid crystal polymers. In the present invention, these liquid crystal materials may be collectively referred to as liquid crystal molecules for convenience.

  It is a polymerizable liquid crystal molecule, particularly a cross-linkable liquid crystal monomer, which is polymerized and cured by irradiation with ionizing radiation such as ultraviolet rays and electron beams in that it can be cured while maintaining the alignment state of the liquid crystal molecules. It is preferable to use one. Since retardation amount and alignment characteristics are determined by the birefringence Δn of the liquid crystal molecules and the thickness of the birefringence functional layer, Δn is preferably about 0.03 to 0.15.

More specifically, the liquid crystal material contained in the liquid crystal composition used for forming the birefringence functional layer has an unsaturated double bond in its molecular structure and is three-dimensionally crosslinked in the liquid crystal state. Thus, a polymerizable liquid crystal material that can fix the liquid crystal structure is conceivable. Here, as the polymerizable liquid crystal material, compounds included in the following (Chemical Formula 1) to (Chemical Formula 11) can be used alone or in combination of two or more. In the case of the liquid crystalline monomer represented by the general formula (Formula 11), X is preferably 4 to 6 (integer). Here, since the retardation amount and the alignment characteristics are determined by the birefringence Δn and the film thickness of the liquid crystal molecules, Δn is preferably about 0.03 to 0.20, more preferably about 0.05 to 0.15.
The liquid crystal material can be applied by being dissolved in various organic solvents. The organic solvent is not particularly limited as long as the liquid crystal material is dissolved, but it is preferable that the organic solvent can be uniformly coated on the substrate. In addition, when the substrate is given water / oil repellency, or when the added surfactant has strong water / oil repellency, UV cleaning and plasma treatment should be performed as long as the vertical alignment ability is not hindered. It is also possible to improve paintability.

  Moreover, it is preferable to mix | blend a photoinitiator in the said liquid crystal composition in the range which does not impair the alignment of a liquid crystal molecule, and the radical polymerization initiator which generate | occur | produces a free radical by the energy of an ultraviolet-ray is preferable. As a compounding quantity of a photoinitiator, it is about 0.01%-15% (mass reference | standard with respect to a liquid-crystal composition), More preferably, it is about 0.5%-10% (same).

  Specific examples of the photopolymerization initiator include benzyl (also called bibenzoyl), benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-benzoyl-4'-methyldiphenyl sulfide, benzylmethyl Ketal, dimethylaminomethylbenzoate, 2-n-butoxyethyl-4-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, 3,3′-dimethyl-4-methoxybenzophenone, methylobenzoyl formate, 2-methyl- 1- (4- (methylthio) phenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 1- (4 -Dodecylpheny ) -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2- Hydroxy-2-methylpropan-1-one, 2-chlorothioxanthone, 2,4-diethylthioxanthone 2,4-diisopropylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propoxythioxanthone, etc. be able to.

(About liquid crystal display devices)
A liquid crystal display device 51 using the color filter 10 of the present invention will be described with reference to FIG.
FIG. 4 is a schematic cross-sectional view of a liquid crystal display device 51 including the color filter 10 of the present embodiment. As the liquid crystal display device 51, a so-called IPS driving method is exemplified, but other driving methods such as an MVA driving method and an OCB driving method may be used.

In the liquid crystal display device 51, the color filter 10 is incorporated as a display-side substrate on the viewer side (upper side in the figure) facing the viewer. A liquid crystal driving substrate 71 including a driving liquid crystal layer 40 including driving liquid crystal molecules 41 and a liquid crystal driving electrode 72 is laminated on the color filter 10 from the viewer side toward the backlight 90 side (downward in the figure). Is provided. The backlight used in combination with the color filter 10 of this embodiment is white light, and the radiant intensities of the main wavelengths of red, blue, and green, which are components thereof, are equivalent.
The liquid crystal driving substrate 71 includes a glass substrate 76, a liquid crystal driving circuit 73 provided on the surface of the in-cell side, that is, the driving liquid crystal layer 40, and a liquid crystal driving electrode 72 whose applied voltage is controlled thereby. The liquid crystal driving electrode 72 is formed in a comb-like pattern for each pixel defined by the BM 14.
Further, a horizontal alignment film (not shown) for horizontally aligning the driving liquid crystal molecules 41 is coated on the in-cell side surface of the liquid crystal driving electrode 72.

  The driving liquid crystal layer 40 including the driving liquid crystal molecules 41 is enclosed in a sealed space surrounded by the birefringence functional layer 30, the liquid crystal driving substrate 71, and the seal 48, and is loaded from the liquid crystal driving electrode 72 in the in-panel direction. The driving liquid crystal molecules 41 are switching driven by the applied voltage. In order to secure a desired thickness of the driving liquid crystal layer 40, a plurality of columnar bodies are generally formed between the color filter 10 and the liquid crystal driving substrate 71, but this is illustrated in FIG. Omitted.

  The liquid crystal display device 51 includes a linear polarizing plate 81, a retardation film 82 having an optical compensation function as a positive A plate, a birefringence functional layer 30, a driving liquid crystal layer 40, a linear polarizing plate 83, and a back in order from the viewer side. Light is arranged, and bright display and dark display are performed by controlling transmission or blocking of backlight light for each picture element. In addition, the linearly polarizing plate 81 and the linearly polarizing plate 83 are disposed so that the transmission axis directions are orthogonal to each other.

[Second Embodiment]
FIG. 5 is a schematic vertical sectional view in which the base material 16 and the colored layer 11 in the color filter 10 according to the second embodiment of the present invention are cut in the repeating direction of the colored portion 12. Vertically aligned liquid crystal molecules 50 are applied to the upper surface of the colored layer 11.
The colored portion 12 of the present embodiment is composed of four colors Y (yellow) R (red) G (green) B (blue), and is formed side by side in the order of yellow → red → blue → green by a photolithography method. It is characterized by being. Note that the relative luminous sensitivities of the four colors are green>yellow>red> blue.
In the present embodiment, the colored layer 11 that is made by repeating the photolithography process four times is selected as yellow as the first color, red as the second color, blue as the third color, and green as the fourth color. Yes.

FIGS. 6A to 6F are schematic views illustrating a plate making process of the colored layer 11 in the color filter 10 of the second embodiment.
As a first step, a yellow coloring material 18 (Y) which is a coloring material of the first color is applied directly on the light-transmitting base material 16 or indirectly through another light-transmitting underlayer. Then, this is patterned by a photolithography method (FIG. (A)), and the colored portions 12 (Y) of the first color are dispersed in the width direction (FIG. (B)). The yellow coloring material 18 (Y) is applied to at least an area covering the effective display area, and the colored portion 12 (Y) is formed in a three pixel width interval.

  As a second step, a red coloring material 18 (R), which is a coloring material of the second color, is applied, and this is patterned by a photolithography method ((c) in the same figure), and the colored portion 12 (Y ) In a position adjacent to one side in the width direction (the right side in the figure), the red colored portions 12 (R) are dispersedly formed (the figure (d)).

  As a third step, a blue coloring material 18 (B), which is a third color coloring material, is applied, and this is patterned by a photolithography method, so that one side in the width direction with respect to the second color coloring portion 12 (R). The blue colored portions 12 (B) are dispersed and formed at positions adjacent to the side (right side in the figure) (FIG. (E)).

  As a fourth step, a green coloring material 18 (G) which is a coloring material of the fourth color is applied, and this is patterned by a photolithography method, so that the colored portions 12 (B), A green colored portion 12 (G) is formed at a position adjacent to 12 (Y), and the colored layer 11 is made (FIG. (F)).

  In the colored layer 11 made by the above process, the flat portion 24 is formed at the center in the width direction for the yellow colored portion 12 (Y) of the first color and the green colored portion 12 (G) of the fourth color. For the second color red colored portion 12 (R) and the third color blue colored portion 12 (B), an inclined portion 25 is formed at the center in the width direction.

  In the color filter 10 in which the coloring materials of four colors are sequentially applied and the colored portions of the four colors are fixedly formed adjacent to each other as in the present embodiment, the colored portion 12 (R of the second color as shown in the figure). ) And the colored portion 12 (B) of the third color are substantially asymmetrical in the outer shape, and there is a risk that alignment defects may occur in the liquid crystal molecules 50 applied on the upper surface thereof. The first colored part has no other colored parts on both sides in the width direction, and the fourth colored part has other colored parts on both sides in the width direction. The outer shape is substantially symmetrical, and the second and third colored portions are coated with the coloring material in a state where the colored portions of the other colors are already formed only on one side in the width direction. Is substantially left-right asymmetric.

For the color filter 10 of the present embodiment, the color with the highest luminance (bright field luminance) when this is subjected to bright display is the colored portion (ie, second color or third color) whose outer shape is asymmetrical. By matching the colored part (ie, the first color or the fourth color) whose outer shape is symmetrical, the light leakage during dark display is suppressed and a high contrast ratio is realized. Yes.
More specifically, two colors with the lowest bright field luminance are selected, and these are assigned to the colored portions (that is, the second color and the third color) whose outer shape is asymmetrical.
Specifically, for the case where the external light or the backlight light incident on the colored layer 11 is white light, the blue color with the lowest relative visibility and the second lowest red color among the four colors are selected, These are the second and third colors.
If the radiant intensity of the dominant wavelength transmitted by the colored part of each color is not white light and the backlight is not white light, the radiant intensity and relative luminous sensitivity measured when each color is lit individually Depending on the product size, a color with low bright-field luminance may be selected and applied to the left-right asymmetric pixel.
Note that whether the second color and the third color are blue or red is arbitrary. It is also arbitrary whether the first color and the fourth color are green or yellow.

The colored layer 11 made in the color filter 10 of the present embodiment is added to the red colored portion 12 (R), the blue colored portion 12 (B), and the green colored portion (G) that are fixedly formed in the first embodiment. The yellow coloring part 12 (Y) is provided. The coating thickness in the wet state of the yellow coloring material 18 (Y) forming the yellow coloring portion 12 (Y) is in the range of 1 μm to 4 μm, preferably 1 μm, for the same reason as the red, green and blue coloring portions. It is set within a range of ˜3 μm. The yellow coloring material is mainly composed of a yellow pigment, a binder resin such as a UV curable resin, and a solvent.
However, as the coloring resist constituting the colored transparent coloring portion other than the red (R), green (G), blue (B), and yellow (Y), cyan (C), magenta (M) or white (W Or other known colored resists may be appropriately used to form the colored portion 12 in the present invention.

As a further modification of the present embodiment, the colored layer 11 may be made by coating and forming colored portions of five or more colors side by side in order.
In the case of colored portions of five or more colors, the colored portions of the first color and the fifth color are substantially symmetrical with respect to the outer shape, whereas the colored portions of the second to fourth colors are substantially contoured. Becomes asymmetrical. In the same manner as described above, with respect to the colored portions of the first color and the final color (fifth color), the uneven shape of the base layer to which the coloring material of the color is applied is the same on both sides in the width direction, and other colors ( Regarding the colored portion of the second color to the fourth color), since the colored portion of the other color is already formed only in one of the width directions, the base layer on which the colored material of the color is applied becomes asymmetrical. Because.

  Therefore, in the case of such a five-color filter, it is preferable to select three colors having lower bright field luminance when each color is individually lit, and apply this to the left-right asymmetric pixel. In other words, in the case where the external light or backlight light incident on the color filter 10 is white light, three colors with low relative visibility are selected from among the five colors and assigned to the second color to the fourth color, and the specific vision Two colors with higher sensitivity may be assigned to the first color or the fifth color.

Examples of the present invention will be described in detail below.
(1. Adjustment of substrate)
Glass substrate (1737 glass manufactured by Corning, Inc.) as a base material subjected to cleaning treatment, and photoresist (coloring material) for BM, red (R), green (G), and blue (B) colored portions ) Was prepared. And the photoresist was apply | coated for each color as shown below on the glass substrate upper surface, and the colored layer was laminated | stacked and formed on the base material. The composition of each photoresist will be described later.

(2. Adjustment of coloring material)
A pigment-dispersed photoresist was used as a coloring material for BM and each region. In the pigment dispersion type photoresist, a pigment is used as a coloring material, a bead is added to a dispersion composition (containing a pigment, a dispersant, and a solvent), the dispersion is dispersed for 3 hours by a disperser, and then the bead is removed. A liquid and a clear resist composition (polymer, monomer, additive, disclosure agent and solvent) are mixed. Its composition is shown below. A paint shaker was used as the disperser.

(3. Creation of BM)
First, a BM photoresist prepared as follows is applied to a glass substrate by a spin coating method, pre-baked (pre-baked) at 90 ° C. for 3 minutes, and exposed using a mask formed in a predetermined pattern. (100 mJ / cm ² ), followed by spray development using 0.05% KOH aqueous solution for 60 seconds, followed by post-baking (baking) at 200 ° C. for 30 minutes, width 20 μm, thickness 1.2 μm The base material (BM forming base material) on which BM was formed was produced.

(4. Creation of colored layer)
On the BM forming substrate, a pattern design is made so that a line having a width of 200 μm and a length of 4 cm is 300 rows × 1 column, so that colored portions are repeatedly formed in the order of red, blue, green from the end. Each colored portion was created as follows. It should be noted that, in relation to the BM, the design was made so that both ends of the above-mentioned line exist at positions where the BM is lifted.

First, a red (R) pigment-dispersed photoresist is applied onto the surface of the BM forming substrate by spin coating, dried under reduced pressure to 130 Pa, pre-baked at 80 ° C. for 5 minutes, UV exposure using a photomask for stripe pattern in which a mask opening is patterned so that a red colored portion is formed in the 3n + 1 (n is a positive integer) line with the end of the region as the first. (300 mJ / cm ² ). Further, spray development using a 0.1% KOH aqueous solution was performed for 60 seconds, followed by post-baking (baking) at 200 ° C. for 60 minutes, and a red (R) film having a thickness of 2.0 μm at a predetermined position with respect to the BM pattern. ) A colored portion pattern was formed. In addition, the said film thickness is the thickness of the red (R) coloring part in BM non-formation position, and the height from the base-material surface in both ends which got on BM is 2.7 micrometers, and red (R) The outer shape of the colored portion was substantially symmetrical.

Subsequently, after applying a blue (B) pigment-dispersed photoresist by spin coating, the above red (except for the photomask having a mask opening patterned so that a colored portion is formed in the 3n + 2nd line is used. A blue (B) colored portion was created using a method similar to the method of forming the pattern of the colored portion R).
Among the blue (B) colored portions, the height from the substrate surface at the end on the side adjacent to the red (R) colored portion is 3.5 μm, and the height at the opposite end is 2.8 μm. The outer shape of the blue (B) colored portion was substantially asymmetrical.

Subsequently, after applying a green (G) pigment-dispersed photoresist by a spin coating method, the above red (except the photomask in which the mask opening is patterned so that a colored portion is formed in the 3n + 3rd line is used. A green (G) colored portion was created using a method similar to the method for forming the pattern of the R (blue) and blue (B) colored portions.
Of the green (G) colored portion, the height from the base material surface at both ends adjacent to the blue (B) colored portion and the red (R) colored portion is 3.6 μm on the side adjacent to the blue (B) colored portion, red (R) It was 3.5 μm on the colored portion adjacent side, and the outline shape of the green (G) colored portion was substantially symmetrical.

  In this way, a color filter was formed in which a colored layer composed of BM, a red colored portion, a blue colored portion, and a green colored portion repeatedly arranged in this order was formed on the glass substrate. Further, it was confirmed that only the second colored portion selected as described above had different heights at both ends in the width direction, and the outer shape was substantially asymmetrical.

<Photoresist for black matrix>
Black pigment: 14.0 parts by weight (manufactured by Dainichi Seika Kogyo Co., Ltd. TM Black # 95550)
・ Dispersant: 1.2 parts by weight (Disperbyk 111 manufactured by Big Chemie)
・ Polymer 2.8 parts by weight (VR60 manufactured by Showa Polymer Co., Ltd.)
・ Monomer: 3.5 parts by weight (SR399, manufactured by Sartomer Co., Ltd.)
・ Additives: 0.7 parts by weight (L-20, manufactured by Soken Chemical Co., Ltd.)
Photopolymerization initiator: 1.6 parts by weight (2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1)
-Photopolymerization initiator: 0.3 parts by weight (4,4'-diethylaminobenzophenone)
-Photopolymerization initiator: 0.1 part by weight (2,4-diethylthioxanthone)
・ Solvent: 75.8 parts by weight (ethylene glycol monobutyl ether)

<Red (R) colored portion photoresist>
Red pigment: 4.8 parts by weight (CIPR254 (Chromophthal DPP Red BP manufactured by Ciba Specialty Chemicals))
・ Yellow pigment: 1.2 parts by weight (CI PY139 (manufactured by BASF, Paliotor Yellow D1819))
・ Dispersant ... 3.0 parts by weight (manufactured by Zeneca Corp. Solsperse 24000)
・ Monomer: 4.0 parts by weight (SR399, manufactured by Sartomer Co., Ltd.)
・ Polymer 1 ... 5.0 parts by weight (below)
Photopolymerization initiator: 1.4 parts by weight (Irgacure 907 manufactured by Ciba Geigy)
・ Photopolymerization initiator: 0.6 parts by weight (2,2′-bis (o-chlorophenyl) -4,5,4 ′, 5′-tetraphenyl-1,2′-biimidazole)
・ Solvent: 80.0 parts by weight (propylene glycol monomethyl ether acetate)

<Blue (B) Colored photoresist>
Blue pigment: 4.6 parts by weight (CI PB15: 6 (BASF Heliogen Blue L6700F))
・ Purple pigment: 1.4 parts by weight (CI PV23 (Clariant Foster Palm RL-NF))
・ Pigment derivative ... 0.6 parts by weight (Solsperse 12000 manufactured by Zeneca)
・ Dispersant: 2.4 parts by weight (Solsperse 24000, manufactured by Zeneca Corporation)
・ Monomer: 4.0 parts by weight (SR399, manufactured by Sartomer Co., Ltd.)
・ Polymer 1 ... 5.0 parts by weight (below)
Photopolymerization initiator: 1.4 parts by weight (Irgacure 907 manufactured by Ciba Geigy)
・ Photopolymerization initiator: 0.6 parts by weight (2,2′-bis (o-chlorophenyl) -4,5,4 ′, 5′-tetraphenyl-1,2′-biimidazole)
・ Solvent: 80.0 parts by weight (propylene glycol monomethyl ether acetate)

<Green (G) Colored photoresist>
Green pigment: 3.7 parts by weight (CIPG7 (Seika Fast Green 5316P manufactured by Dainichi Seika))
・ Yellow pigment ・ ・ ・ 2.3 parts by weight (CI PY139 (BASF Pariotor Yellow D1819))
・ Dispersant ... 3.0 parts by weight (manufactured by Zeneca Corp. Solsperse 24000)
・ Monomer: 4.0 parts by weight (SR399, manufactured by Sartomer Co., Ltd.)
・ Polymer 1 ... 5.0 parts by weight (below)
Photopolymerization initiator: 1.4 parts by weight (Irgacure 907 manufactured by Ciba Geigy)
・ Photopolymerization initiator: 0.6 parts by weight (2,2′-bis (o-chlorophenyl) -4,5,4 ′, 5′-tetraphenyl-1,2′-biimidazole)
・ Solvent: 80.0 parts by weight (propylene glycol monomethyl ether acetate)

  In the present specification, the polymer 1 described above is a copolymer of benzyl methacrylate: styrene: acrylic acid: 2-hydroxyethyl methacrylate = 15.6: 37.0: 30.5: 16.9 (molar ratio). 16.9 mol% of 2-methacryloyloxyethyl isocyanate is added to 100 mol%, and the weight average molecular weight is 42500.

(Formation of birefringence functional layer)
A birefringence functional layer was formed on the upper surface of the transparent colored layer by the method described below.

<Formation of vertical alignment film>
First, in order to form a so-called positive C plate as a birefringence functional layer on the transparent colored portion, a vertical alignment film was first formed.
Specifically, using JALS2021 (manufactured by JSR Co., Ltd.) as an alignment film material, patterning is performed on the above color filter by flexographic printing, and then baking is performed at 200 ° C. for 1 hour, thereby achieving a vertical alignment of 600 mm in thickness. A base substrate provided with a film was obtained. In this case, a protective layer made of a transparent resin may be provided between the colored layer and the alignment film. This is because the step of the color filter is relaxed and more reliable liquid crystal alignment is possible.

<Preparation of liquid crystal composition containing polymerizable liquid crystal material>
A liquid crystal composition containing a polymerizable liquid crystal material constituting the birefringent functional layer was prepared as follows.
As a polymerizable liquid crystalline monomer molecule showing a nematic liquid crystal layer, 20 parts by weight of the compound represented by the above (Chemical Formula 11) (wherein X is 6) and a photopolymerization initiator (“Irgacure 907” manufactured by Ciba Geigy Co., Ltd.) ] 0.8 parts by weight, 59.2 parts by weight of chlorobenzene as a solvent, and 20 parts by weight of a solution obtained by diluting the above-mentioned vertical alignment film forming solution JALS-2021-R2 to 12.5% with diethylene glycol dimethyl ether. A liquid crystal composition was prepared.

<Formation of birefringence functional layer>
Next, the prepared liquid crystal composition was placed on a spin coater (manufactured by MIKASA, “trade name 1H-360S”), and the liquid crystal composition prepared in advance was dried. The upper surface of the alignment film was spin-coated so that the subsequent film thickness was about 1.5 μm. In this embodiment, the spin coating method is applied. However, the present invention is not limited to this as long as it can be uniformly applied on the substrate, and may be die coating, slit coating, or a combination thereof. There is no particular limitation.
Subsequently, the substrate is dried under reduced pressure to 130 Pa, and then heated on a hot plate at 100 ° C. for 3 minutes to remove the residual solvent and to align the liquid crystalline monomer contained in the liquid crystal solution in the vertical direction. The alignment of the liquid crystal molecules was confirmed by visually confirming the liquid crystal transition point at which the film formed by the above became transparent from white. Subsequently, under a nitrogen atmosphere, the entire surface of the liquid crystal coating film is irradiated with ultraviolet rays (20 mW / cm ² , 365 nm, 10 nm) using an ultraviolet irradiation device (“TOSCURE 751” manufactured by Harrison Toshiba Lighting Co., Ltd.) having an ultrahigh pressure mercury lamp. Second), the polymerizable liquid crystal molecules constituting the liquid crystal layer were three-dimensionally crosslinked and cured. It was heated and baked on a 230 ° C. hot plate for 60 minutes to complete the curing reaction, and a birefringence functional layer of a positive C plate having a thickness of 1.45 μm was obtained.

(Comparative Example 1)
The red colored part is formed in the 3n + 1th line so that the colored part is formed in order of red, green, and blue to form the colored layer, that is, the colored material selected for the second color is green. After that, a green colored portion is formed using a photomask in which a mask opening is patterned so that a colored portion is formed in the 3n + 2 line, and then a mask opening is formed so that a colored portion is formed in the 3n + 3 line. A color filter was prepared in the same manner as in Example 1 except that a blue colored portion was formed using a patterned photomask, and Comparative Example 1 was obtained.

(Evaluation 1) Light Leakage Evaluation In order to evaluate the performance of whether or not light leakage is prevented when light is transmitted through the color filter, light leakage of Example 1 was evaluated by the following method.

  The polarizing microscope CPX31-P manufactured by Olympus Corporation was set in a crossed Nicol state for the sample of Example 1 created as described above, and light was applied with the color filter of Example 1 sandwiched between the polarizing plate provided in the microscope. The substrate was rotated in the state, and the presence or absence of light leakage was observed with the naked eye. As a result, light leakage is observed at the end portion adjacent to the red pixel that is first coated and formed among the pixels (blue pixels) corresponding to the blue colored portion that is coated and formed second. It was.

  For Comparative Example 1, a sample was formed in the same manner as in Example 1, and then light leakage was evaluated. As a result, light leakage is observed at the end adjacent to the first pixel formed red color among the pixels (green pixels) corresponding to the second color formed green part (green pixel). It was.

(Evaluation 2) Measurement of front luminance Front luminance is measured using a luminance measurement system constructed with a luminance measuring device, a color filter with a birefringence functional layer, a polarizing plate, and a light irradiation unit that emits light. The measurement was performed by measuring the dark field luminance when all colors were darkly displayed.

  In the luminance measurement system, the luminance measuring device includes an optical sensor that detects light passing through a color filter with a birefringence functional layer sandwiched between polarizing plates in a crossed Nicol state among white light emitted from a light irradiation unit, and an optical sensor. And a measuring unit that measures the luminance based on the signal detected by. Specifically, “BM-9” manufactured by Topcon Corporation was used as a luminance measuring instrument for measuring luminance.

  Using the above luminance measurement system, the front luminance was measured as follows. First, a color filter with a birefringence functional layer is arranged with two polarizing plates sandwiched in a crossed Nicol state, a light irradiation part is arranged outside the first polarizing plate, and a color filter with a birefringence functional layer is sandwiched between them. The optical sensor was arranged at the position facing the thickness direction of the liquid crystal layer and outside the second polarizing plate.

Next, light is emitted from the light irradiating unit toward the liquid crystal display device, and the light that has passed through the cell from the position outside the second polarizing plate and has passed through the first polarizing plate is detected by the optical sensor. The amount of brightness (luminance) was measured by the measurement unit, and the front luminance was measured. As a result of the above measurement, the front luminance of Example 1 was 0.41 [cd / m ² ].

Also in Comparative Example 1, as in Example 1, front luminance was measured according to the above evaluation 2. As a result, the front luminance of Comparative Example 1 was 4.00 [cd / m ² ].

From the results of the above evaluations 1 and 2, according to the color filter of the present invention, light leakage that occurs when visible light is transmitted is reduced. For example, when used as a substrate on one side of a liquid crystal display, a high-quality image is obtained. Can be provided.
Specifically, from the result of evaluation 1, it was observed that light leakage during dark display occurred predominantly from the pixels corresponding to the colored portions coated and formed on the second color. Subsequently, in Example 1 in which blue having a low specific visibility is selected as the second color from the result of evaluation 2, the front luminance (dark field luminance) is significantly higher than that in Comparative Example 1 in which green having a high specific visibility is selected. It was found that the light leakage that is known to the observer is reduced and a high contrast ratio is realized.

It is the vertical cross-section schematic diagram which cut | disconnected the color filter 10 concerning 1st embodiment in the repeating direction of the coloring part. (A)-(f) shows the preparation process of the color filter 10 concerning 1st embodiment. 2 is a schematic cross-sectional view of the color filter 10. FIG. 3 is a schematic cross-sectional view of a liquid crystal display device 51 including a color filter 10. FIG. It is the vertical cross-section schematic diagram which cut | disconnected the color filter 10 concerning 2nd embodiment in the repeating direction of the coloring part. (A)-(f) shows the preparation process of the color filter 10 concerning 2nd embodiment. It is a schematic diagram regarding the vertical cross section of the colored layer formed in the conventional color filter. (A)-(f) shows the preparation process of the conventional color filter.

Explanation of symbols

10 Color Filter 11 Colored Layer 12 Colored Part 14 Black Matrix (BM)
16 Base material 18 Coloring material 20 Photomask 22, 23 Convex part 24 Flat part 25 Inclined part 30 Birefringence functional layer 40 Drive liquid crystal layer 50 Liquid crystal molecule 51 Liquid crystal display device 71 Liquid crystal drive substrate 90 Backlight

Claims (3)

A liquid crystal display device in which a color filter, a driving liquid crystal layer including driving liquid crystal molecules, a liquid crystal driving substrate including a liquid crystal driving electrode, and a backlight device are arranged in this order from the viewer side,
The color filter is directly or indirectly on a light-transmitting substrate, and a colored layer in which a plurality of colored portions of four or more colors are sequentially arranged with at least one direction as a repeating direction, and polymerizable liquid crystal molecules A color filter formed by laminating a birefringence functional layer fixed in a state oriented in a desired direction in this order ,
The colored layer is composed of a colored portion whose color is substantially symmetrical in the outer shape of a vertical section cut in the repeating direction, and a colored portion whose color is substantially asymmetric in the outer shape,
The color of the left-right asymmetric coloring part is two or more colors,
The two or more colors are colors having the highest luminance when the color filter is subjected to bright display for each of the plurality of colors according to the radiation intensity of the main wavelength of the backlight light in the backlight device. A color that does n’t match is selected,
In addition, for the two or more colors, the luminance is lowest when the color filter is subjected to bright display for each of the plurality of colors in accordance with the emission intensity of the main wavelength of the backlight light in the backlight device. A liquid crystal display device comprising a color . 2. The backlight according to claim 1, wherein backlight light in the backlight device is white visible light, the plurality of colors include red, blue, and green, and the two or more colors include blue . Liquid crystal display device. The liquid crystal display device according to claim 1, wherein the polymerizable liquid crystal molecules are homeotropically aligned .

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