JP4696474B2 - Polishing method of color filter for liquid crystal display device - Google Patents

Description

  The present invention relates to a color filter for a liquid crystal display device, and in particular, improves the bonding strength between a resin black matrix and a sealing material in a seal portion in a polishing process of a color filter for a liquid crystal display device having a resin black matrix formed thereon The present invention relates to a method for manufacturing a color filter for a liquid crystal display device.

FIG. 3 is a plan view schematically showing an example of a color filter used in the liquid crystal display device. 4 is a cross-sectional view of the color filter shown in FIG. 3 taken along line XX ′.
As shown in FIGS. 3 and 4, the color filter used in the liquid crystal display device has a black matrix (51) and colored pixels (52) formed on a glass substrate (30).
3 and 4 schematically show a color filter, and nine colored pixels (52) are represented. In an actual color filter, for example, several hundreds are displayed on a 14-inch diagonal screen. A large number of colored pixels of about μm are arranged.

The black matrix (51) is light-shielding and has openings arranged in a matrix, 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.

This black matrix (51) is an example in which a resin is used as a black matrix material on a glass substrate (30).
The black matrix (51) is formed on the glass substrate (30) by, for example, a photolithography method using a black photosensitive resin for forming a black matrix, and the black matrix formed using the resin. Is referred to as a resin black matrix (51).

Further, the peripheral edge (G) of the color filter is a portion called a picture frame. FIGS. 3 and 4 are examples in which the resin black matrix is formed up to the frame portion, that is, the edge of the peripheral edge (G) of the color filter.
The direct light from the backlight is shielded up to the edge of the peripheral edge (G) of the color filter, and the function of reducing the stray light incident from the end face of the color filter and improving the contrast of the image is provided.

  Further, the colored pixel (52) is provided with a coating film on the glass substrate (30) on which the resin black matrix (51) is formed, using, for example, a negative photoresist in which pigments and other pigments are dispersed. The coated film is formed as a colored pixel by exposure through a photomask and development processing.

The resin black matrix, for example, causes internal reflection in a liquid crystal display device that occurs when a metal such as chromium is used as a black matrix (not shown) when using a high-brightness backlight such as a television. In order to suppress a low-reflection resin black matrix, or in order to suppress an electric field disturbance in a liquid crystal display device when used in, for example, an IPS (In Plane Switching) system, a high insulation is required. It has been adopted when a functional resin black matrix is required. 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.

  This transition is likely to become significant as the glass substrate becomes larger. There is also a tendency to avoid using metals such as chromium in consideration of the environment.

The resin black matrix cannot obtain a high concentration in a thin film with a film thickness of about 100 nm to 200 nm, like a black matrix using a metal such as chromium, for example, a thickness of about 0.5 μm to 3.0 μm. To obtain the necessary high concentration.
When the film thickness of the resin black matrix is increased to, for example, about 1.0 μm, as shown in FIG. 4, the colored pixel (52) formed by overlapping the peripheral portion on the resin black matrix (51) The peripheral edge becomes a protrusion (53) on the resin black matrix (51).

  This protrusion (53) makes the surface of the color filter uneven, and deteriorates flatness. When a color filter having such a protrusion (53) and having a deteriorated surface flatness is used in a liquid crystal display device, the alignment of liquid crystal molecules is disturbed by the influence of the protrusion, and display quality such as display unevenness is deteriorated. Therefore, in many cases, the protrusions are removed by polishing the surface of the color filter.

FIG. 1 and FIG. 2 are explanatory views showing an outline of an example of a flat plate polishing machine generally used when polishing the surface of a color filter for a liquid crystal display device. FIG. 1 is a sectional view of a rotating part of a flat plate polishing machine, and FIG. 2 is a plan view.
As shown in FIG. 1 and FIG. 2, the rotating part of this polishing machine includes a disk-shaped lower surface plate (1), a rotating shaft (2) that is fixed integrally with the lower surface plate and rotates the lower surface plate, and is settled by friction. It is composed of a disk-shaped upper surface plate (3) that rotates following the rotation of the plate, and a rotation axis (4) of the upper surface plate.

The size of the upper surface plate (3) is smaller than that of the lower surface plate (1), and the upper surface of the lower surface plate (1) swings in an arc shape while rotating following the rotation of the lower surface plate by the friction. (C) to do. A set polishing pressure (D) can be applied from the upper part of the upper surface plate (3).
Polishing is performed while dripping a polishing liquid (not shown) from above the color filter (6). Reference numeral (5) indicates a polishing cloth, (7) indicates a template, (A) indicates rotation of the lower surface plate, and (B) indicates rotation of the upper surface plate.

Polishing to the surface of the color filter removes the protrusions and at the same time removes the residue of the photoresist remaining on the colored pixels and the resin black matrix. It is preferable for the adhesiveness of the film or for the adhesiveness of the sealing material when the peripheral edge (frame) (G) is used as the sealing portion with the counter substrate.

However, even if the protrusions on the surface of the color filter are removed by the polishing process as described above, and the residue of the photoresist is removed, the abrasive particles remain on the resin black matrix, and the remaining abrasive particles remain on the resin black in the seal portion. There is a problem that the bonding strength between the matrix and the sealing material is lowered.
For this reason, after the polishing process, the color filter is again washed with an alkaline surfactant to remove the abrasive particles remaining on the resin black matrix.

FIG. 5 is an explanatory diagram of a seal portion in which the peripheral edge (frame) (G) of the color filter shown in FIG. 4 is enlarged.
The glass substrate (30) and the counter substrate (40) are integrated as a panel by a sealing material (60) through a resin black matrix (51). The bonding strength at the bonding portion (S) between the resin black matrix (51) and the sealing material (60) is lowered by the remaining abrasive particles.
Japanese Patent Laid-Open No. 9-268032 Japanese Patent Application No. 2002-349599 Japanese Patent Application No. 2004-057127

The present invention has been made to solve the above problems, and remains in the resin black matrix in the polishing process of the color filter surface when manufacturing the color filter for a liquid crystal display device on which the resin black matrix is formed. It is an object of the present invention to provide a polishing method for a color filter for a liquid crystal display device capable of reducing polishing particles and improving the bonding strength between a resin black matrix and a sealing material in a seal portion.
As a result, in the color filter in which the resin black matrix is formed up to the edge of the peripheral edge (frame) (G) of the color filter, the color filter is again washed with an alkaline surfactant after the polishing process. Thus, a color filter with improved bonding strength can be obtained.

The present invention relates to a polishing method for a color filter for a liquid crystal display device in which a resin black matrix is formed , using a polishing liquid having a pH value that mixes alkali and negatively charges the surface of the abrasive particles as a polishing liquid. a polishing method of a color liquid crystal display device filter, characterized in that to improve the bonding strength between the resin black matrix and the seal member in the row, sealed portion.

  Since the present invention is a polishing method for a color filter for a liquid crystal display device that performs a polishing process using a polishing liquid having a pH value that negatively charges the surface of the abrasive particles as the polishing liquid, This is a method for polishing a color filter for a liquid crystal display device that can reduce the abrasive particles remaining in the resin black matrix and improve the bonding strength between the resin black matrix and the sealing material in the seal portion.

  As a result, in the color filter in which the resin black matrix is formed up to the edge of the peripheral edge (frame) (G) of the color filter, the color filter is again washed with an alkaline surfactant after the polishing process. Thus, a color filter with improved bonding strength can be obtained.

Hereinafter, embodiments of the present invention will be described in detail.
The present inventor has found that in polishing, abrasive particles, particularly alumina particles, are likely to remain on the surface of the resin black matrix because charging is a major factor, that is, the surface of the resin black matrix and the abrasive particles have different signs. Attention was paid to this point and the present invention was reached.

  According to the present invention, the reason why the bonding strength between the resin black matrix and the sealing material in the seal portion is remarkably improved is not yet clear, but in the polishing liquid according to the present invention, the resin black formed on the glass substrate. It is presumed that since the ζ (zeta) potentials of the matrix surface and the abrasive particle surface are both negatively charged, it is difficult for the abrasive particles to remain.

The polishing liquid is obtained by dispersing abrasive particles in water. As the abrasive particles, alumina, zirconia, cerium, manganese dioxide, silicon carbide, silica, or the like having a primary particle size of 0.03 to 0.2 μm may be used. it can.
The pH value of the polishing liquid is a pH value that negatively charges the surface of the abrasive particles to be used, and differs depending on the type of the abrasive particles. For adjusting the pH value, for example, NaOH, KOH or the like is suitably used as the alkali.
The polishing machine used for polishing is not particularly limited as long as the polishing machine uses abrasive particles.

The following polishing liquid was used as the polishing liquid.
Polishing liquid 1
Abrasive particles: SiO ₂ , average particle size: 40 nm
・ Content: 50w%
・ PH value: 10.0
Polishing liquid 2
Abrasive particles: SiO ₂ , average particle size: 23 nm
・ Content: 40w%
・ PH value: 9.8
Polishing liquid 3 (reference liquid)
Abrasive particles: α-Al ₂ O ₃ , secondary particle size: 100 nm
・ Content: 1w%
-PH value: 7.0.

As the polishing machine, an Oscar-type flat plate polishing machine is used. Polishing cloth: suede cloth, polishing pressure: about 150 Pa, rotation speed of lower surface plate: about 40 rpm, dropping amount of polishing liquid: 60 g / min, polishing time: 1 minute Polishing was performed under the conditions. After polishing, sponge brush cleaning was performed in pure water.
The sample used is a color filter in which a resin black matrix is formed.

  The resin black matrix and the glass plate at the peripheral edge (frame) of the color filter after polishing were bonded together using XN-21S (Mitsui Chemicals, epoxy thermosetting resin) as a sealing material. # 1737 (manufactured by Corning) was used for the glass plate. After bonding, the strength when the bonded portion was broken was measured with a pressure cracker. The results are shown in Table 1.

表１に示すように、研磨液１及び研磨液２において、ｐＨ値７．０に調整した研磨液３（参照液）より貼り合わせ強度が向上している。特に研磨液２において、著しい効果が得られている。

As shown in Table 1, in the polishing liquid 1 and the polishing liquid 2, the bonding strength is improved as compared with the polishing liquid 3 (reference liquid) adjusted to a pH value of 7.0. In particular, in the polishing liquid 2, a remarkable effect is obtained.

It is sectional drawing of the rotation part of an example of the flat plate grinder which grind | polishes the surface of the color filter for liquid crystal display devices. It is a top view of the rotation part of an example of the flat plate grinder which grind | polishes the surface of the color filter for liquid crystal display devices. It is the top view which showed typically an example of the color filter for liquid crystal display devices. It is sectional drawing in the X-X 'line | wire of the color filter shown in FIG. It is explanatory drawing of the seal | sticker part which expanded the peripheral part (frame) of the color filter shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lower surface plate 2 ... Rotating shaft 3 which rotates a lower surface plate 3 ... Upper surface plate 4 ... Rotating shaft 5 of an upper surface plate ... Polishing cloth 6 ... Glass substrate (color filter)
7 ... Template 7A ... Template backing material 7B ... Template frame material 30 ... Glass substrate 40 ... Counter substrate 51 ... Resin black matrix 52 ... Colored pixel 53 ... Protrusion 60 ... Sealing material A ... Lower platen rotation B ... Upper platen rotation C ... Oscillation D ... Polishing pressure G ... Peripheral edge (frame) of color filter
S: Bonding part

Claims (1)

In the polishing method of a color liquid crystal display device resin black matrix formed filter, as a polishing liquid, it has rows polishing treatment using a polishing solution having a pH value to negatively charged surface of the abrasive particles by mixing an alkali seal A method for polishing a color filter for a liquid crystal display device, comprising improving the bonding strength between a resin black matrix and a sealing material in a part .

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