Color filter patterned by screen printing

Through the analysis of the screen printing process and experiments for uniform printing, the color filter for the liquid crystal display panel is screen printed. For maintaining the same printing condition on the whole area, the static deformation is analyzed and the optimal squeegee velocity is formulated. Various printing conditions are experimented with various screen mesh sizes, emulsion pattern depths, squeegee types and angles, off-contact distances, printing pressure, inks, and so on. Several kinds of ink are tested from the viewpoint of viscosity, contact angle, chromatography, and other rheological characteristics of ink. Color filters are printed on the liquid crystal display glass with a black matrix pattern. The average thicknesses of blue, red, and green patterns are 2.5 mu m, 3.4 mu m, and 2.3 mu m, respectively. The color reproducibility is 72.8% in the National Television System Committee. The transmittance spectral characteristics of red, green, and blue inks are higher than 70%. (C) 2008 Elsevier B.V. All rights reserved.