1. Field of the Invention
The present invention relates to a method of fabricating a black matrix of a color filter, and more particularly, to a method of fabricating a black matrix of a color filter that can improve brightness uniformity.
2. Description of the Related Art
Conventionally, cathode ray tube (“CRT”) monitors have been used for displaying information of televisions (“TVs”) or computers. Recently, as a display screen increases in size, flat panel display devices are used for displaying the information. Examples of the flat panel display devices include a liquid crystal display (“LCD”), a plasma display panel (“PDP”), an electroluminescence (“EL”) display, a light emitting diode (“LED”) display, and a field emission display (“FED”). The LCD is widely used as a computer monitor and as a notebook PC display because of its low power consumption.
The LCD includes a color filter for creating an image of a desired color by transmitting white light modulated by a liquid crystal layer. The color filter includes a plurality of red (“R”), green (“G”) and blue (“B”) pixels that are arranged in a predetermined pattern on a transparent substrate and are partitioned by a black matrix.
FIGS. 1A and 1B are sectional views illustrating a conventional method of fabricating the black matrix of a color filter. Referring to FIG. 1A, an upper surface of a transparent substrate 10 is coated to a predetermined thickness with a black matrix layer 12 formed of a hydrophobic organic material, and the black matrix layer 12 is baked. Referring to FIG. 1B, the black matrix layer 12 is patterned to form patterns 15 of a black matrix. FIG. 2 is a sectional view of a color filter that is manufactured using the black matrix fabricated by the conventional method illustrated in FIGS. 1A and 1B. Referring to FIG. 2, regions among the black matrix patterns 15 are coated with ink 17 of a given color to form pixels, thereby manufacturing the color filter.
However, since the side surfaces (i.e., the side walls) of the black matrix patterns 15 are hydrophobic and have a large contact angle with the ink 17, the substrate 10 is not coated to a uniform thickness with the ink 17, as illustrated in FIG. 2. Accordingly, light leakage occurs near the side surfaces of the black matrix patterns, and thus light emitted from the respective pixels of the color filter has a brightness that is non-uniform across a given pixel.
FIGS. 3A through 3C are sectional views illustrating another conventional method of fabricating a black matrix of a color filter, which is disclosed in Japanese Patent Laid-open Publication No. 2000-162426. This method provides side surfaces of black matrix patterns that are hydrophilic, unlike the method illustrated in FIGS. 1A, 1B, and 2. Referring to FIG. 3A, an upper surface of a transparent substrate 20 is coated to a predetermined thickness with a black matrix layer 22 formed of a hydrophobic organic material, and the black matrix layer 22 is baked. Referring to FIG. 3B, the black matrix layer 22 is patterned to form patterns 25 of a black matrix. Referring to FIG. 3C, a lower surface of the transparent substrate 20 is exposed to ultraviolet (“UV”) rays such that the UV rays irradiate the side surfaces of the black matrix patterns but do not irradiate the upper surfaces of the black matrix patterns 25. Consequently, while the upper surfaces of the black patterns 25 maintain their hydrophobicity, the side surfaces of the black patterns 25 become hydrophilic by adsorbing moisture from air.
However, the above method does not fundamentally alter the side surfaces of the black matrix patterns 25 to make them hydrophilic.