JP2008281678A - Color filter manufacturing method, color filter, and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a color filter by which the color filter, where height of a projection is made low, a groove between colored pixels is eliminated and film thickness level difference between the colored pixels is made small, is manufactured at a low cost without providing an overcoat layer and thereby to provide the color filter having no display inferiority or the like due to rotation and inclination or the like of a liquid crystal molecule even when used for a liquid crystal display apparatus. <P>SOLUTION: A resin black matrix 51 is formed on a glass substrate 50, the colored pixels are formed so that peripheral parts of adjoining colored pixels 62 are overlapped on the resin black matrix and height of the projection 63 of the colored pixel is made to be 0.5 μm or less by polishing. Overlapping amount of the peripheral parts W12 is 0 μm or more. The film thickness level difference between colors is 0.2 μm or less. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a color filter for a liquid crystal display device, and in particular, a method for manufacturing a color filter that is inexpensively manufactured without providing an overcoat layer in the manufacture of a color filter using a resin black matrix, and an inexpensive It relates to a color filter.

In a display device, it is a useful means to use a color filter for purposes such as color display, reflectance reduction, contrast improvement, and spectral characteristic control.
In many cases, the color filter used in the display device is formed as a pixel. A photolithography method is widely used as a method of forming pixels of a color filter used in this display device.

FIG. 4 is a plan view schematically showing an example of a color filter used in the liquid crystal display device. FIG. 5 is a cross-sectional view taken along the line XX ′ of the color filter shown in FIG.
As shown in FIGS. 4 and 5, the color filter used in the liquid crystal display device has a black matrix (51), a colored pixel (52), and a transparent conductive film (54) sequentially formed on a glass substrate (50). It has been done.
4 and 5 schematically show a color filter, and 12 colored pixels (52) are represented. In an actual color filter, for example, several hundreds are displayed on a 17-inch diagonal screen. A large number of colored pixels of about μm are arranged.

The black matrix (51) is a matrix having light shielding properties, and the colored pixels (52) have, for example, red, green, and blue filter functions.
The black matrix determines the position of the colored pixels of the color filter, makes the size uniform, and shields unwanted light when used in a display device, making the image of the display device uniform and uniform. In addition, it has a function of making an image with improved contrast.

The black matrix was formed by forming a metal such as chromium (Cr) or chromium oxide (CrO _x ) as a black matrix material or a metal compound in a thin film on a glass substrate (50). An etching resist pattern is formed on the thin film using, for example, a positive type photoresist, and then the exposed portion of the formed metal thin film is etched and the etching resist pattern is stripped, and Cr, CrO _x, etc. The method of forming the black matrix (51) which consists of a metal thin film of this is taken.

Alternatively, a method is used in which a black matrix (51) is formed on a glass substrate (50) by a photolithography method using a black photosensitive resin for forming a black matrix.
The black matrix (51) shown in FIG. 4 and FIG. 5 is an example formed on a glass substrate (50) by a photolithography method using a black photosensitive resin for forming a black matrix. The black matrix thus formed is referred to as a resin black matrix (51).

For the colored pixel (52), a negative photosensitive colored resin composition in which a pigment such as a pigment is dispersed on the glass substrate (50) on which the resin black matrix (51) is formed is used. It is formed as a colored pixel by a photolithography method, that is, by exposure to a coating film of the photosensitive colored resin composition through a photomask and development processing. Red, green, and blue colored pixels are sequentially formed.
The film thickness of the colored pixel (52) varies depending on the color characteristics of the colored pixel, and is about 1.0 μm to 3.0 μm.

  Further, the transparent conductive film (54) is formed on the glass substrate (50) on which the resin black matrix (51) and the colored pixels (52) are formed by using, for example, ITO (Indium Tin Oxide) and transparent by sputtering. A method of forming a conductive film is used.

  Resin black matrix (51) suppresses internal reflection in a liquid crystal display device that occurs when a thin metal film such as chromium is used as a black matrix when using a high-brightness backlight such as a television. In order to suppress the disturbance of the electric field in the liquid crystal display device that occurs when a resin black matrix having a lower reflectivity than the metal thin film is desired, or when used in, for example, an IPS (In Plane Switching) method, Furthermore, it has been adopted when a resin black matrix having high insulation properties is desired. However, the black matrix is gradually shifting from a black matrix using a metal such as chromium to a resin black matrix.

When a large number of color filters are manufactured, a color filter corresponding to a single liquid crystal display device is manufactured in a state where it is applied to a large glass substrate. For example, a 17-inch diagonal color filter is manufactured by attaching four faces to a large glass substrate of about 650 mm × 850 mm.
Resin black matrix formed by photolithography using a black photosensitive resin rather than a black matrix that uses a metal such as chromium as a black matrix material to form a thin film with a vacuum device as the glass substrate becomes larger Is becoming more advantageous in terms of price, and is gradually shifting to a resin black matrix. Moreover, it tends to avoid using metals such as chromium in consideration of the environment.

The resin black matrix (51) cannot obtain a sufficient concentration for shading with a thin film having a film thickness of about 100 nm to 200 nm, such as a black matrix using a metal thin film such as chromium. The required high concentration is obtained by setting the thickness to about 1.5 μm.
The resin black matrix (51) has a thickness of about 1.0 μm to 1.5 μm. Therefore, when forming a black matrix having a finer line width than a black matrix using a metal thin film such as chromium. Is disadvantageous.

  Further, when the thickness of the resin black matrix becomes as thick as about 1.0 μm to 1.5 μm, as shown in FIG. 5, the colored pixels (52 formed by overlapping the peripheral portion on the resin black matrix (51). ) Is a projection (swelling) (53) on the edge of the resin black matrix (51).

FIG. 6 is an enlarged cross-sectional view of the vicinity of the protrusion (53) shown in FIG. As shown in FIG. 6, for example, a resin black matrix (51) having a film thickness (T3) of about 1.3 μm and a width (W) of about 20 μm is provided, and the film thickness (T1, T2) of the colored pixels (52R, 52G). In a color filter having a thickness of about 1.8 μm, the height (H) of the protrusion (swell) (53) may be 0.5 μm or more.
Further, for example, when the thickness of the resin black matrix (51) is about 1.5 μm and the thickness of the colored pixel (52) is about 2.0 μm, the height (H) of the protrusion (swell) (53) is It may be 1.0 μm or more.

Such protrusions (swells) on the edge of the resin black matrix (51) (5
3), the groove (M) formed between the red colored pixel (52R) and the green colored pixel (52G) on the resin black matrix (51), and the film thickness (T1) of the red colored pixel (52R) and the green color. When a color filter in which a film thickness step (film thickness difference) (ΔT, ΔT = T1 to T2) between the film thicknesses (T2) of the pixels (52R) is formed in the liquid crystal display device, the liquid crystal molecules are tilted. As a result, display quality such as display failure or light leakage around the pixel is adversely affected.
For example, when the height (H) of the protrusion (swell) (53) is approximately 0.5 μm or more, the display quality is hindered.

In particular, the horizontal electric field type (IPS mode) liquid crystal display device is a mode in which display is mainly performed by the birefringence effect. Therefore, when the gap between the substrates changes, the birefringence deviates from the optimum value, so that coloring occurs. Reduce quality. That is, the in-plane variation of the gap between the substrates is visually recognized as in-plane unevenness of display characteristics.
Therefore, in order to avoid the influence of the protrusions (53) on the end of the resin black matrix (51) or the foreign matter on the colored pixels (52) and obtain a display without in-plane unevenness, an IPS liquid crystal is used. In the case of a color filter used in a display device, an overcoat layer is formed as a planarization process.

However, in actual work, the overcoat layer made of a transparent resin has hindered the yield due to uneven coating and generation of foreign matter. In recent years, the cost of liquid crystal display devices has been remarkably reduced, and there is a strong demand for cost reduction of the color filter that is a member thereof. With regard to the overcoat layer, there are problems such as improvement in yield of the overcoat layer, simplification of the process of the overcoat layer, and deletion of the overcoat layer.
FIG. 3 is a cross-sectional view showing an example of a black matrix in which a metal thin film such as chromium is used as the black matrix material. As shown in FIG. 3, since the film thickness of this black matrix is about 100 nm to 200 nm, there is almost no influence of protrusions (swells) on the end of the black matrix (51).
JP 2006-227295 A JP 2006-227296 A Japanese Patent Laid-Open No. 9-189899 JP 2005-357828 A

The present invention has been made to solve the above problems, and in a method for manufacturing a color filter in which a resin black matrix and colored pixels are sequentially formed on a glass substrate, the height of protrusions (swells) is low. Even if it is used in a liquid crystal display device without a groove between the colored pixels and with a small film thickness difference between the colored pixels and used in a liquid crystal display device without providing an overcoat layer, a display defect or a peripheral portion of the pixel It is an object of the present invention to provide a color filter manufacturing method capable of manufacturing an inexpensive color filter that does not hinder display quality such as light leakage.
It is another object of the present invention to provide an inexpensive color filter manufactured using the above-described color filter manufacturing method and a liquid crystal display device manufactured using the color filter.

  Accordingly, it is possible to manufacture a color filter having no protrusions (swells), grooves, or film thickness steps that hinder display quality. Therefore, the color filter flattening process such as the formation of an overcoat layer, which has been conventionally performed when a projection (swell) or the like that hinders display quality, is unnecessary.

The present invention relates to a method for producing a color filter in which at least a resin black matrix and colored pixels are sequentially formed on a glass substrate.
1) forming a resin black matrix on the glass substrate;
2) forming colored pixels so that peripheral edges of adjacent colored pixels overlap on the resin black matrix;
3) A method for producing a color filter, wherein the height of protrusions (swells) of colored pixels caused by the overlap is 0.5 μm or less by polishing treatment.

  The present invention is also the color filter manufacturing method according to the invention described above, wherein the overlapping amount of the peripheral portion of the colored pixel is 0 μm or more.

  The present invention is also the color filter manufacturing method according to the above invention, wherein a film thickness difference between colors of the colored pixels is 0.2 μm or less.

  Moreover, this invention is a color filter of the horizontal electric field system (IPS system) manufactured using the manufacturing method of the color filter of any one of Claims 1-3.

  The present invention also provides a liquid crystal display device manufactured using the color filter according to claim 4.

  In the present invention, a resin black matrix is formed on a glass substrate, colored pixels are formed so that peripheral edges of adjacent colored pixels overlap on the resin black matrix, and the protrusions of the colored pixels generated by the above overlap by a polishing process. Since the height of (swell) is 0.5 μm or less, or the overlapping amount of the peripheral portion of the colored pixel is 0 μm or more and the overlapping amount of the peripheral portion of the colored pixel is 0 μm or more, the protrusion (swell) The height is low, the groove between the colored pixels is eliminated, and the film thickness difference between the colored pixels is small. Therefore, it is possible to manufacture an inexpensive color filter that does not hinder display quality such as display failure or light leakage at the periphery of a pixel due to tilting of liquid crystal molecules even when used in a liquid crystal display device without providing an overcoat layer. It becomes the manufacturing method of the color filter which can be performed.

  In addition, since the present invention is a color filter manufactured using the above-described method for manufacturing a color filter, it is an inexpensive color filter free from protrusions (swells), grooves, and film thickness steps that hinder display quality.

Hereinafter, a color filter manufacturing method and a color filter embodiment according to the present invention will be described in detail.
FIGS. 1A to 1B are cross-sectional views illustrating an embodiment of a method for manufacturing a color filter according to the present invention. FIG. 1A is a cross-sectional view showing a stage in which a resin black matrix (51) and colored pixels are sequentially formed on a glass substrate (50).
The colored pixels are formed in the order of a red colored pixel (62R), a green colored pixel (62G), and a blue colored pixel (62B).

As shown in FIG. 1A, the first color red colored pixel (62R) is a red colored pixel (62R).
R) is formed on the resin black matrix (51) between the adjacent green colored pixel (62G) with its peripheral edge overlapped, and the red colored pixel formed on the resin black matrix (51). The peripheral edge of the second color green colored pixel (62G) is formed to overlap the peripheral edge of (62R).
On the periphery of the red colored pixel (62R), a protrusion (swell) (63) is generated at the portion where the peripheral edge of the green colored pixel (62G) overlaps.

Further, the peripheral edge of the green colored pixel (62G) on the blue colored pixel (62B) side is on the resin black matrix (51) between the green colored pixel (62G) and the adjacent blue colored pixel (62B). The peripheral edge portion is formed so as to overlap, and the peripheral edge portion of the third color blue colored pixel (62B) overlaps the peripheral edge portion of the green colored pixel (62G) formed on the resin black matrix (51). Is formed.
A protrusion (swell) (63) is generated in the overlapped portion.

The peripheral edge of the blue colored pixel (62B) on the red colored pixel (62R) side is formed on the resin black matrix (51) between the blue colored pixel (62B) and the adjacent red colored pixel (62R). The peripheral edge of the third color blue colored pixel (62B) is formed so as to overlap the peripheral edge of the red colored pixel (62R), and a protrusion (swell) (63) is generated in the overlapped portion. .
FIG. 1B is a cross-sectional view showing a stage where a polishing process is subsequently performed. As shown in FIG. 1B, the height (H12) of the protrusion (swell) (63 ′) after polishing is higher than the height (H11) of the protrusion (swell) (63) before polishing. It is low (H12 <H11).

The present invention will be specifically described below with reference to examples.
<Example 1>
On the glass substrate (50), a resin black matrix (51) having a thickness of 1.5 μm was formed. Next, as shown in FIG. 1A, colored pixels having a film thickness (T11) of 2.0 μm were formed in the order of red colored pixels (62R), green colored pixels (62G), and blue colored pixels (62B). The overlapping amount (W11) of the peripheral edge of the colored pixel on the resin black matrix (51) was 2.0 μm. At this time, the height (H11) of the protrusion (swell) (63) was 1.48 μm.

  Next, a polishing process was performed, and the height (H12) of the protrusion (swell) (63 ') after polishing was set to 0.2 μm. At this time, the overlapping amount (W12) of the peripheral portion of the colored pixel was 2.0 μm, and the film thickness difference (ΔT12) between the colors of the colored pixels (62R, 62G, 62B) was 0.1 μm.

  The display quality of the liquid crystal display device manufactured using the color filter obtained as described above was good without display defects due to tilting of liquid crystal molecules and light leakage at the periphery of the pixels. The height of the protrusion (swell) in Example 1 is a small value such as 0.2 μm, and there is no groove (M) between the colored pixels as shown in FIG. (ΔT12) is a small value such as 0.1 μm. That is, the conventional overcoat layer formation is unnecessary.

<Example 2>
On the glass substrate (50), a resin black matrix (51) having a thickness of 1.5 μm was formed. Next, as shown in FIG. 1A, colored pixels having a film thickness (T11) of 2.0 μm were formed in the order of red colored pixels (62R), green colored pixels (62G), and blue colored pixels (62B). The overlapping amount (W11) of the peripheral portion of the colored pixel on the resin black matrix (51) was 6.0 μm. At this time, the height (H11) of the protrusion (swell) (63) was 1.60 μm.

Next, a polishing process was performed, and the height (H12) of the protrusion (swell) (63 ′) after polishing was set to 0.5 μm. At this time, the overlapping amount (W12) of the peripheral portion of the colored pixel was 6.0 μm, and the film thickness step (ΔT12) between the colors of the colored pixels (62R, 62G, 62B) was 0.1 μm.
The display quality of the liquid crystal display device manufactured using the color filter obtained as described above was good without display defects due to tilting of liquid crystal molecules and light leakage at the periphery of the pixels.

<Comparative Example 1>
2A and 2B are cross-sectional views illustrating Comparative Example 1. FIG. FIG. 2A is a cross-sectional view showing a stage in which a resin black matrix (51) and colored pixels are sequentially formed on a glass substrate (50).
The colored pixels are formed in the order of a red colored pixel (62R), a green colored pixel (62G), and a blue colored pixel (62B).

As shown in FIG. 2A, the first color red colored pixel (62R) is placed on the resin black matrix (51) between the red colored pixel (62R) and the adjacent green colored pixel (62G). The peripheral edge of the green colored pixel (62G) of the second color is formed on the side of the peripheral edge of the red colored pixel (62R) formed on the resin black matrix (51). It is formed to overlap.
The portion where the peripheral edge of the green colored pixel (62G) overlaps the peripheral edge of the red colored pixel (62R) is not a protrusion (swell) but a concave shape (65).

Further, the peripheral edge of the green colored pixel (62G) on the blue colored pixel (62B) side is on the resin black matrix (51) between the green colored pixel (62G) and the adjacent blue colored pixel (62B). The peripheral edge portion is overlapped, and the peripheral edge portion of the third color blue colored pixel (62B) overlaps the peripheral edge side surface of the green colored pixel (62G) formed on the resin black matrix (51). It is formed as follows.
This overlapped portion is concave (65).

  The peripheral edge of the blue colored pixel (62B) on the red colored pixel (62R) side is formed on the resin black matrix (51) between the blue colored pixel (62B) and the adjacent red colored pixel (62R). On the side surface of the peripheral edge of the red colored pixel (62R), the peripheral edge of the third color blue colored pixel (62B) is formed so as to overlap, and the overlapped portion has a concave shape (65).

FIG. 2B is a cross-sectional view showing a stage where the polishing process is subsequently performed. As shown in FIG. 2B, the height (H22) of the protrusion (swell) (63 ′) after polishing is higher than the height (H21) of the protrusion (swell) (63) before polishing. It is low (H22 <H21).
However, the concave portion (65) becomes a groove (M) between the colored pixels, and the surface of the resin black matrix (51) is exposed.

In Comparative Example 1, a resin black matrix (51) having a film thickness of 1.5 μm was formed on a glass substrate (50). Next, as shown in FIG. 2A, colored pixels having a film thickness (T21) of 2.0 μm were formed in the order of red colored pixels (62R), green colored pixels (62G), and blue colored pixels (62B). Overlap amount (W of the peripheral edge of the colored pixel on the resin black matrix (51)
21) was 1.0 μm. At this time, the height (H21) of the protrusion (swell) (63) on the resin black matrix (51) was 0.5 μm.

Next, a polishing process was performed, and the height (H22) of the protrusion (swell) (63 ′) after polishing was set to 0.2 μm. At this time, the film thickness difference (ΔT22) between the colors of the colored pixels (62R, 62G, 62B) was 0.2 μm.
The display quality of the liquid crystal display device manufactured using the color filter obtained as described above was not good due to display defects due to tilting of liquid crystal molecules and light leakage at the pixel periphery.

<Comparative example 2>
In Comparative Example 2, a color filter having the structure shown in FIG. The difference from Example 1 is that the overlapping amount (W11) of the peripheral portion of the colored pixel is 3.0 μm, and the height (H12) of the projection (swell) (63 ′) after polishing is 0.6 μm. It is. At this time, the film thickness difference (ΔT12) between colors of the colored pixels was 0.2 μm.
The display quality of the liquid crystal display device manufactured using the obtained color filter was not good due to display defects due to tilting of liquid crystal molecules and light leakage at the periphery of the pixel.

<Comparative Example 3>
In Comparative Example 3, the color filter having the structure shown in FIG. The difference from Example 1 is that the overlapping amount (W11) of the peripheral portion of the colored pixel is 3.0 μm, and the height (H12) of the projection (swell) (63 ′) after polishing is 0.1 μm. It is. At this time, the film thickness difference (ΔT12) between colors of the colored pixels was 0.3 μm.
The display quality of the liquid crystal display device manufactured using the obtained color filter was not good due to display defects due to tilting of liquid crystal molecules and light leakage at the periphery of the pixel.

  The evaluation results of the above examples are shown in Table 1. In Table 1, symbol “◯” indicates that the display quality is good, and symbol “x” indicates that the display quality is poor.

(A) is sectional drawing which shows the step in which the resin black matrix and the colored pixel were sequentially formed on the glass substrate. (B) is sectional drawing which shows the step to which the grinding | polishing process was performed subsequently. (A) is sectional drawing explaining the comparative example 1, and is sectional drawing which shows the step in which the resin black matrix and the colored pixel were formed in order on the glass substrate. (B) is sectional drawing which shows the step to which the grinding | polishing process was performed subsequently. It is sectional drawing which shows an example of the black matrix using metal thin films, such as chromium. It is the top view which showed typically an example of the color filter used for a liquid crystal display device. FIG. 5 is a cross-sectional view taken along line X-X ′ of the color filter illustrated in FIG. 4. It is sectional drawing to which the vicinity of the protrusion shown in FIG. 5 was expanded.

Explanation of symbols

50 ... Glass substrate 51 ... Resin black matrix 52 ... Colored pixel 52R ... Red colored pixel 52G ... Green colored pixel 53 ... Projection (swell)
54 ... Transparent conductive film 62 ... Colored pixel 62R in the present invention ... Red colored pixel 62G in the present invention ... Green colored pixel 62B in the present invention ... Blue colored pixel 63 in the present invention ... Protrusion (swell) in the present invention
63 '... projection 65 after polishing in the present invention ... concave portion H where the peripheral edge of the colored pixel in Comparative Example 1 overlaps ... height H11 of the projection (swell) ... projection in the present invention (Swelling) height H12 ... Polishing protrusion (swelling) height H21 ... Comparative example 1 protrusion (swelling) height H22 ... Comparative example 1 polishing (swelling) Height M... Grooves T1, T2, T11, T21 formed between the colored pixels. Colored pixel film thickness T3... Resin black matrix film thickness T12, T22. Film thickness ΔT: film thickness difference between colored pixels (film thickness difference)
W: Resin black matrix width W11, W21: Colored pixel peripheral edge overlapping amount W12, W22: Polished colored pixel peripheral edge overlapping amount

Claims (5)

In a method for producing a color filter that sequentially forms at least a resin black matrix and colored pixels on a glass substrate,
1) forming a resin black matrix on the glass substrate;
2) forming colored pixels so that peripheral edges of adjacent colored pixels overlap on the resin black matrix;
3) A method for producing a color filter, wherein the height of protrusions (swells) of the colored pixels caused by the overlap is 0.5 μm or less by polishing.   The method for manufacturing a color filter according to claim 1, wherein an overlapping amount of a peripheral portion of the colored pixel is 0 μm or more.   The method for manufacturing a color filter according to claim 1, wherein a film thickness difference between colors of the colored pixels is 0.2 μm or less.   A horizontal electric field type (IPS type) color filter manufactured using the method for manufacturing a color filter according to claim 1.   A liquid crystal display device manufactured using the color filter according to claim 4.

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