| The "color-by-blue" technology is utilized in electroluminescent display in order to get full-color. blue backlight could be converted to green light and red light and the full-color flat display can be achieved by combination of the three colors through color conversion film. This is often called the "color-by-blue" technology. The "color-by-blue" technology not only simplifies the already manufacturing process for electroluminescent display, but also offers large savings in capital and operating costs. SVA company has made greats effort preparationing materials which eradiates blue backlight. Furthermore, fluorescent organic pigment is dispersed in UV-curable resin, and then deposited onto the ITO glass by means of a screen printed method. And UV-curable technology has numerous advantages compared with of traditional technology, such as economy, efficiency, ecology, and energy. The main components of color conversion film were determined from the resultant of physical properties of UV-curable clear coatings. Photoinitiator 1104 was selected from three kinds of photoinitiators due to its higher hardness, better tenacity, less yellowing, and perfecting match with blue light. Concentrations of the remained photoinitiator 1104 in the clear coating decreased with curing-time and increased with the photoinitiator 1104 in the solutions. Comparing effects of monomer HDDA and TMPTA on clear coating, HDDA was chosen because the clear coating comprised of HDDA was crack free. Increasing the ratio of monomer to resin, the stress and hardness of the as-prepared clear coatings increased, and the strain and tenacity of clear coatings decreased.Preparation technology of UV-curable color conversion film was discussed in this research. The influences of concentration of photoinitiator 1104, curing-time, concentration of fluorescent pigment, composite of different fluorescent pigments, thickness of color conversion film, luminance of blue light on conversion-color purity and color conversion efficiency E were discussed as well. It was found that the UV-curing time of CCF was longer than that of the clear coatings with the same concentration of photoinitiator 1104 same in the two systems, which could be explained by the absorption of fluorescent pigment to ultraviolet light. Efficiency of color conversion film decreased with the curing time. The maximal emission wavelength of blue light was just the max excitation wavelength of fluorescent pigments VQ-25, FA-16 and VQ-20, so energy of the blue light could be transferred to the fluorescent pigment, and then be converted to light. The blue light was also matched with fluorescent pigments. Luminous of the blue light would be lower through transmitting between fluorescent pigments, this is called attenuation of fluorescent pigment. The maximal emission of the fluorescent pigment excited by 700 nm light was 466 nm, and the maximal emission of the fluorescent pigment excited by 466 nm light was 700 nm, which determinated attenuation of fluorescent pigments. When the color conversion film was 20μm thick, the concentrations of VQ-24 and VQ-25 were between 40% and 45%, the values of CIE coordinates X was between 0.47 and 0.60, Y between 0.20 and 0.30, and the viscosity of coatings was between 80000 mPa·s and 90000 mPa·s, so coatings could be printed and the conversion color was purity. It was found the color conversion efficiency E of Orange red CCF was better than that of red CCF. The values of CIE coordinates X was 0.60, Y was 0.32, and E was 99% when the concentration of FBI-400 was 43%. The values of CIE coordinates X was 0.47, Y was 0.30, and E was 80% when the total concentration of pigments was 45%, and the weight ratio of VQ-25 to FBI -203 was 1:1. The values of CIE coordinates X was 0.49, and Y was 0.30, and E was 52% when the total concentration of pigments was 45%, and the weight ratio of FBI-403 to FBI -203 was 1:1. The values of CIE coordinates X was 0.27, and Y was 0.63, and E was 200% when the total concentration of fluorescent pigment VQ-20 was 37%. More blue light would transmit color conversion film to made conversion light not purity if the thickness of CCF was too thinner. Meanwhile, all lights would be prevented from transmitting color conversion film to lower efficiency of color conversion film if color conversion film was too thicker. Luminance of conversion color increased with the luminance of blue light increased, while as the color conversion efficiency E was not changed correspondingly. |
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