Ceramic materials (phosphors) for plasma display panel

Abstract

Phosphors the ceramic materials should able to work in tough environment surrounded and bombarded by high energy Vacuum Ultra Violet (VUV) or electron beam radiations in any discharge tube. The plasma display panel (PDP) is increasingly gaining attention over conventional cathode ray tube (CRT)-based TVs as a medium of large format (60+") television(TV), particularly high definition TVs (HDTVs). Improvements have been made not only in size but also in other areas such as resolution, luminescence efficiency, brightness, contrast ratio, power consumption, and cost reduction. The performance of a PDP depends on a complicated set of factors, for instance, phosphors, gas mixture, dielectric layer, reflective layer, black matrix, electrodes, cell dimension and shape, nature, size and shape of electrodes, address waveforms, and operating voltages. The formation of a phosphor host and doping process by solid solution is critical and is highly dependent on the reaction on the reaction temperature and conditions. Since the purity of starting chemicals is very important to the synthesis of phosphors, the starting chemicals are typically 99.9–99.999% in purity. Required amounts of starting ingredients are mixed in the presence of an appropriate flux (if necessary) and fired at high temperatures (900-1500°C) in air or in a controlled atmosphere (N2, C, CO, or N2 with 2–5% of H2). Zn2-xMnxSiO4 is a classical green emitting phosphor, and it has been used in many applications, such as CFL, CRT, PDP etc. In this paper, Zn2SiO4:Mn2+ green phosphor was synthesized using the solid-state reaction method. Photoluminescence and crystalline properties were examined as functions of the firing temperatures. Zn2-xMnxSiO4 was ground and fired at 1200 °C for 4 hours in air, but intensity of emission is weak. Therefore the conditions of firing were changed and Zn2-xMnxSiO4 was grinded and fired at 1000°C for 2 hours in air and again grinded and fired at 1200 °C for 4 hour in air respectively. When varies SiO2 value from 0.9 to 1.8 however the ZnO is 1.92 as well as MnCO3 is 0.08 are constant. The SiO2 concentration (1.1) show good PL Spectra. The PL peak observed at 524 nm in these phosphors suggests their potential use as green emitting phosphors under 254 nm excitation.