The role of a diffusion barrier in plasma display panel with the high gamma cathode layer

Abstract

Plasma display panel (PDP) with MgO-SrO double cathode layer and SiO 2 diffusion barrier is proposed to make the SrO layer free of contaminations. Time of flight-secondary ion mass spectrometry (TOF-SIMS) analysis shows the diffusion of impurities, like Na and K, can be effectively blocked while a new SrO layer is formed on top of the MgO layer. This structure shows that high Xe gases can be used to improve the luminous efficacy 2.3 times and decrease the voltage margin more than 10 V compared to the conventional PDP using Ne-Xe 15%. The aging time was also significantly decreased to 3-4 h. Plasma display panel (PDP) can provide vivid, high quality images and so is suited for the display of realistic 3-dimensional (3D) images. PDP has made big improvements in its luminous efficacy and power consumption over the years, but still needs further progress in order to meet the green products requirements. 1 One of the effective methods used to reduce the discharge voltage and increase the luminous efficacy of a PDP is to use a high gamma cathode layer. MgO has been one of the most widely used cathode materials; however, it has limitations because of the large band gap energy of about 7 eV, too large to induce the secondary electron emissions through the Auger neutralization process using Xe ions. [2][3][4] There have been many attempts to apply other alkaline earth metal oxides such as SrO and CaO, which have a lower band gap energy and, therefore, a higher secondary electron emission coefficient for Xe ions when compared to MgO. 5,6 However, these materials have limitations when applied to PDP using the normal fabrication process, since they are very unstable and highly reactive with H 2 O or CO 2 , resulting in the formation of hydroxides or carbonates when exposed to air. In a recent research, which used a mixture of SrO and CaO, the luminous efficacy almost doubledwith a Ne-Xe 30% content gas compared to that of a panel using the conventional MgO employing NeXe 10%. 4 However, the panel assembly fabrication process needed to be carried out in either a nitrogen gas atmosphere or in a vacuum. Another method which does not require a special sealing process but still allows the use of the high gamma property of SrO or CaO had been suggested. 7 It uses a double cathode layer structure consisting of a maincathode layer of an alkaline earth metal oxide like SrO and a protecting MgO layer. It has been shown that a panel with the double cathode layer could retain the high gamma properties of the SrO main-cathode layer, so that the high luminous efficacy and low driving voltage could be realized even though the conventional sealing process was used. However, the panels with the double cathode layer or binary alloy needed a long aging time of 30-40 h for the stabilization of the discharge voltages, compared to the MgO single cathode layer panel. 7-10 Based on the findings from the time of flight-secondary ion mass spectrometry(TOF-SIMS) analysis of the cathode layer, we suggest a diffusion barrier between the dielectric and ...

High Temperature Oxidation Behavior of Hypoeutectic Mg–Sr Binary Alloys: The Role of the Two‐Phase Microstructure and the Surface Activity of Sr

“…[43] Studies on thin films have also shown that SrO layer forms on top of MgO due to Sr out diffusion. [44] It is therefore likely that Sr out diffuses faster than the other species and exhibits enhanced oxidizing on the top surface.…”