JP2005055598A - Method of polishing color filter for liquid crystal display device and color filter for liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of polishing the color filter for a liquid crystal display device capable of uniformly polishing the entire surface of the color filter, drastically reducing the dispersion of the film thickness of colored pixels and drastically reducing the dispersion of chromaticity, and to provide the color filter for the liquid crystal display device manufactured by using the same polishing method. <P>SOLUTION: When high projections 53 formed by superposition of the colored pixels on the edge part of a resin black matrix are eliminated by using a surface grinding machine, the projections are ground and eliminated by using, as the frame material 17B of a template, a frame material having a thickness T2 which is 85% to <100% of the thickness T1 100% of the color filter for the liquid crystal display device. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a color filter for a liquid crystal display device, and in particular, polishes a projection of a color filter having a high projection caused by an overlap between a resin black matrix and a colored pixel using a flat plate polishing machine. The present invention relates to a method for manufacturing a color filter for a liquid crystal display device that, when removed, reduces the variation in the thickness of the colored pixels and greatly reduces the variation in the chromaticity of the color filter.

  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 taken along line X-X ′ of the color filter shown in FIG. 3.

  As shown in FIGS. 3 and 4, the color filter used in the liquid crystal display device has a black matrix (31) and colored pixels (32) formed on a glass substrate (30).

  3 and 4 schematically show a color filter, and nine colored pixels (32) 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 (31) has light shielding properties and has openings arranged in a matrix, and the colored pixels (32) 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 (31) is formed by forming a metal or a metal compound such as chromium (Cr) or chromium oxide (CrO _x ) as a black matrix material into a thin film on a glass substrate (30). An etching resist pattern is formed on the thin film using, for example, a positive type photoresist, and then an exposed portion of the formed metal thin film is etched and an etching resist pattern is peeled off to form Cr, CrO _x It is formed on a black matrix (31) made of a metal thin film.

  In addition, the colored pixels (32) are formed on the glass substrate (30) on which the black matrix (31) is formed by using, for example, a negative photoresist in which pigments and other pigments are dispersed. And a method of forming colored pixels by exposing and developing the coating film is employed.

  FIG. 5 is a cross-sectional view taken along line X-X ′ of the color filter shown in FIG. 3, and shows an example in which a resin is used as a black matrix material.

  Similar to the color filter shown in FIG. 4, this color filter is obtained by forming a black matrix (51) and colored pixels (52) 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).

  In order to suppress internal reflection in a liquid crystal display device that occurs when a metal such as chrome is used as a black matrix when using a high-brightness backlight such as a television, for example, In order to suppress electric field disturbance in a liquid crystal display device when a low-reflection resin black matrix is desired or used in an IPS (In Plane Switching) system, for example, a highly insulating resin black matrix is used. It has been adopted when there is a need. 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 14-inch diagonal color filter is attached to four large-sized glass substrates of about 550 mm × 650 mm, or a 17-inch diagonal color filter is applied to four large-sized glass substrates of about 650 mm × 850 mm. To manufacture.

  As a large-sized glass substrate used for mass production by imposing a color filter increases in size from, for example, about 450 mm × 550 mm to about 550 mm × 650 mm, about 650 mm × 850 mm, the material of the black matrix As a result, the resin black matrix formed by photolithography using a black photosensitive resin becomes more advantageous in price than the black matrix using a metal such as chromium as a thin film with a vacuum apparatus. The transition to the matrix is progressing.

  This transition is likely to become remarkable as the large-sized glass substrate further increases in size to about 900 mm × 1100 mm in the future.

  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 becomes as thick as about 1.0 μm, for example, as shown in FIG. 5, the colored pixels (52) formed by overlapping the peripheral portion on the resin black matrix (51) The portion becomes a protrusion (53) on the resin black matrix (52).

  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. .

  For example, in FIG. 5, when a colored pixel (52) having a thickness of about 0.5 μm to 3.0 μm is formed on a resin black matrix (51) having a thickness of about 1.3 μm, the protrusion (53) is formed. The height (H) is about 0.5 μm to 3.0 μm.

  In the case of a black matrix using a metal, since the film thickness is about 100 nm to 200 nm, such protrusions are few.

  In many cases, the protrusions are removed by polishing on the surface of the color filter, and at the same time, for example, the residue of the photoresist remaining on the colored pixels and on the peripheral edge of the glass substrate is also removed. This is preferable for the adhesiveness of the transparent conductive film in film formation or for the adhesiveness of the sealing agent when the peripheral portion is used as a seal portion with the counter substrate.

  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).

  A polishing cloth (5) is bonded onto the lower surface of the upper surface plate (3), and a template (7) is provided on the upper surface of the lower surface plate (1).

  The template (7) is obtained by bonding the backing material (7A) and the frame material (7B). The backing material (7A) is used for preventing scratches on the glass substrate (color filter) 6, preventing uneven polishing, and improving the adsorptivity, and also surrounds the glass substrate (color filter) 6 (7B). ) Is used in order to prevent the glass substrate (color filter) 6 being removed from being removed.

  The thickness of the frame member (7B) is about 20% thinner than the thickness of the glass substrate (color filter) 6.

  In the polishing method, first, a glass substrate (color filter) (6) is attached in the template (7) on the upper surface of the lower surface plate (1) so that the colored pixels of the color filter face upward. In this pasting, the back surface of the glass substrate (color filter) (6) and the top surface of the backing material (7A) are wetted with water and pasted using the surface tension of water.

  Next, a polishing liquid (not shown) is dropped from above the glass substrate (color filter) (6), the upper surface plate (3) is lowered, a set polishing pressure (D) is applied, and a motor (not shown) ) To drive the rotating shaft (2) and rotate (A) the lower surface plate (1) in a fixed direction. Driving is not applied to the rotating shaft (4) of the upper surface plate (3), and the upper surface plate (3) is rotated (B) following the rotation of the lower surface plate (1). Further, the upper surface plate (3) is caused to swing in an arc shape (C).

  In this way, the surface of the glass substrate (color filter) (6) is polished.

As the polishing cloth (5), a foamed resin material or a non-woven fiber material having a JIS hardness of about 85 is used. Further, as the polishing liquid, one in which an abrasive such as alumina, zirconia, cerium, manganese dioxide, silicon carbide, silica, etc. having a primary particle size of 0.03 to 0.2 μm is dispersed is used. The content of the abrasive is about 1 wt%.

  The polishing pressure is about 1600 Pa, the rotation speed of the lower surface plate is about 30 rpm, and the required time is about 40 seconds.

  However, when 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 entire surface of the color filter is not necessarily uniform, and a difference occurs in the thickness of the colored pixels.

  When the polishing process is performed with a color filter corresponding to one liquid crystal display device being applied to a large glass substrate, the thickness of the colored pixels at the peripheral portion is larger than the thickness of the colored pixels at the central portion of the glass substrate. Thus, a difference in film thickness called so-called sag occurs.

  A difference in the film thickness of the colored pixels is not preferable because it results in variations in chromaticity of the color filter.

This variation in chromaticity has been allowed until now, but it has been strongly demanded to reduce the variation in chromaticity as the quality of liquid crystal display devices is improved.
JP-A-5-66306 Japanese Patent Laid-Open No. 5-134106 Japanese Patent Laid-Open No. 10-282330 JP 2002-71928 A

  The present invention has been made in response to the above-mentioned demands, and in manufacturing a color filter for a liquid crystal display device, in the polishing process of the color filter surface using a flat plate polishing machine, the entire surface of the color filter is more completely removed. Color filter for liquid crystal display device that can polish uniformly and can greatly reduce the variation of film thickness of colored pixels, that is, can reduce surface sag and greatly reduce variation of chromaticity of color filter It is an object of the present invention to provide a polishing method.

  It is another object of the present invention to provide a color filter for a liquid crystal display device manufactured using the above-described method for polishing a color filter for a liquid crystal display device.

  In the present invention, a thick colored pixel is sequentially formed on a glass substrate in a state where the peripheral edge overlaps with the edge of the resin black matrix and the resin black matrix, and is caused by overlapping with the colored pixels on the edge. When the protrusions of the color filter for liquid crystal display devices having high protrusions are removed using a flat plate polishing machine, as a template frame material, the thickness of the color filter for liquid crystal display devices is 100%. A method for polishing a color filter for a liquid crystal display device, characterized by polishing and removing using a frame material having a thickness of 85% to less than 100%.

  The present invention also provides a color filter for a liquid crystal display device manufactured by the method for polishing a color filter for a liquid crystal display device according to the above invention.

  The present invention, when removing the protrusions of the color filter for a liquid crystal display device having a protrusion having a high height caused by overlapping with colored pixels on the edge of the resin black matrix using a flat plate polishing machine, As the frame material of the template, the frame material having a thickness of 85% to less than 100% is polished and removed with respect to the thickness of the color filter for the liquid crystal display device 100%. This is a method for polishing a color filter for a liquid crystal display device that can greatly reduce the variation in chromaticity.

  Moreover, since the present invention is a color filter for a liquid crystal display device manufactured using the above-described method for polishing a color filter for a liquid crystal display device, the surface sagging is reduced and the chromaticity variation is greatly reduced. Color filter.

  Hereinafter, embodiments of the present invention will be described in detail.

  Factors that cause variation in the thickness of the colored pixel in a flat plate polishing machine include polishing pressure, rotation speed of the lower surface plate, rocking width of the upper surface plate, hardness of the polishing cloth, packing, polishing time, polishing solution Examples thereof include a composition and a dropping method of the polishing liquid.

  The present inventor has examined the above factors, and that the polishing pressure is a major factor, that is, the polishing pressure applied to the glass substrate (color filter) is the peripheral portion on the glass substrate (color filter). We focused on the point that is caused by the eccentric load due to the inclination of the upper surface plate.

  As a result of repeated experiments, it was possible to eliminate the eccentric load due to the inclination of the upper surface plate and find a polishing condition that can polish the entire surface of the color filter more uniformly.

  FIG. 6 is a partial sectional view showing the relationship between the thickness of the glass substrate (color filter) and the thickness of the frame material of the template in the method for polishing a color filter for a liquid crystal display device according to the present invention.

  As shown in FIG. 6, a polishing cloth (5) is bonded to the lower surface of the upper surface plate (3), and a template (17) is provided on the upper surface of the lower surface plate (1). In the present invention, the thickness (T2) of the frame material (17B) of the template is 85% to less than 100% with respect to 100% of the thickness (T1) of the glass substrate (color filter) (6). By maintaining the thickness (T2) of the frame member (17B) within this range, the eccentric load due to the inclination of the upper surface plate (3) can be eliminated.

  FIG. 7 is an enlarged view of a portion of an example of the flat plate polishing machine shown in FIG. 1, and shows the thickness (T1) of the glass substrate (color filter) (6) and the thickness (T3) of the frame member (7B). It is explanatory drawing which shows a relationship.

  The thickness (T3) of the frame material (7B) of the template is 80 ± 5% of the thickness (T1) of the glass substrate (color filter) (6), and the thickness (T1) and thickness (T3) The step (d) is 20 ± 5%. When the thickness (T3) of the frame material (7B) of the template is less than 75%, the glass substrate (color filter) (6) is extruded from the frame material (7B) during the polishing process, and the template (7 ) Is easily removed from the home position.

  Further, when the thickness (T3) of the frame material (7B) of the template is 100%, the frame material (7B) is also pressurized to the same extent as the glass substrate (color filter) (6). Increases and the time for polishing the glass substrate (color filter) becomes longer.

  Therefore, considering the separation of the glass substrate (color filter) and the work efficiency, the thickness (T3) of the frame member (7B) is 80 ± 5 of the thickness (T1) of the glass substrate (color filter) (6). % Thickness.

  When the thickness (T3) of the frame material (7B) is 80 ± 5% of the thickness (T1) of the glass substrate (color filter) (6), the present inventor assumes that the glass substrate (color filter) The reason for the occurrence of so-called surface sagging in which the film thickness of the colored pixel at the peripheral portion becomes thinner than the film thickness of the colored pixel at the center of the above is estimated as follows.

  That is, FIG. 8 is an explanatory view showing a state of polishing when the thickness (T3) of the frame member is 80 ± 5% of the thickness (T1) of the glass substrate (color filter) (6).

  FIG. 8 shows that the glass plate (color filter) (6) is pasted in the template (7) on the upper surface of the lower surface plate (1), the upper surface plate (3) is lowered, and the set polishing pressure is applied to the lower surface plate. Rotate (1) in a certain direction, let the upper surface plate (3) rotate following the rotation of the lower surface plate (1), and make the upper surface plate (3) swing in an arc shape, The upper surface plate (3) shows the state when the glass substrate (color filter) (6) reaches the periphery to the frame material (7A).

  As shown in FIG. 8, when the upper surface plate (3) reaches the peripheral part of the glass substrate (color filter) (6) to the frame member (7B), the upper surface plate (3) ) The step (d) between the thickness (T1) of (6) and the thickness (T3) of the template frame member (7B) has an inclination (θ) corresponding to the step (d). .

  When the upper surface plate (3) is tilted in this way, the applied polishing pressure becomes an inclined eccentric load, and the load at the peripheral edge (F) of the glass substrate (color filter) (6) increases. The peripheral portion (F) is excessively polished. This is the guess.

  In addition, this inclination (θ) is a universal joint structure in which the joint (E) connecting the disk-shaped upper surface plate (3) and the rotating shaft (4) of the upper surface plate shown in FIG. Therefore, the inclination is likely to occur.

  In the present invention, as described above, as the frame material (7B) of the template, the thickness (T2) of 85% to less than 100% with respect to 100% of the thickness (T1) of the glass substrate (color filter) (6). ) By using the frame material, the eccentric load due to the inclination of the upper surface plate (3) was eliminated, and the variation in the thickness of the colored pixels of the color filter was greatly reduced.

In other words, the variation in the thickness of the colored pixels is represented by the variation in chromaticity. When the variation in chromaticity between the central portion and the peripheral portion in one conventional glass substrate (color filter) is 100, the polishing of the present invention is performed. According to the method, the variation in chromaticity was approximately 50, which was greatly reduced.

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 sectional drawing in the X-X 'line | wire of the color filter shown in FIG. It is a fragmentary sectional view which shows the relationship between the thickness of a glass substrate and the thickness of the frame material of a template in the grinding | polishing method of the color filter for liquid crystal display devices by this invention. It is explanatory drawing which expands a part of example of the flat plate grinder shown in FIG. 1, and shows the relationship between the thickness of a glass substrate (color filter), and the thickness of a frame material. It is explanatory drawing which shows the state of grinding | polishing in case the thickness of a frame material is 80 +/- 5% of the thickness of a glass substrate (color filter).

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 17 ... Template 17A according to the present invention ... Template backing material 17B according to the present invention ... Template frame according to the present invention Material 30 ... Glass substrate 31 ... Black matrix 32, 52 ... Colored pixel 51 ... Resin black matrix 53 ... Projection A ... Lower plate rotation B ... Upper plate rotation C ... Oscillation D ... Polishing pressure E ... Joint F ... Periphery H of glass substrate (color filter) ... Projection height T1 ... Glass substrate (color filter) Thickness T2 ... thickness T3 of the template frame material according to the present invention ... thickness of the template frame material

Claims (2)

  A thick colored pixel is sequentially formed on the glass substrate with the peripheral edge overlapping the edge of the resin black matrix and the resin black matrix, and a high height is generated by overlapping the colored pixels on the edge. When the protrusions of the color filter for liquid crystal display device having protrusions are removed using a flat plate grinder, the template frame material is 85% to 100% of the thickness of the color filter for liquid crystal display device. A method for polishing a color filter for a liquid crystal display device, characterized by polishing and removing using a frame material having a thickness of less than 100%.   A color filter for a liquid crystal display device produced by the method for polishing a color filter for a liquid crystal display device according to claim 1.