Ultra-thin shadow-mask plasma display panel and NB-UVB source

Abstract

Summary form only given. A type of ultra-thin shadow-mask plasma microdischarge device is being developed for the high-quality display and UVB phototherapy. Thanks to the 150 μm shadow-mask and the 70 μm borosilicate glass with a dielectric constant of 6.7, a sealed panel can be fabricated as thin as 300 μm while the thickness of the device with electrode bandings can be made less than 1 mm1. The shadow-mask is a special metal mesh which is used to form the discharge cells and embed phosphors. The upper part of the discharge cell has a diamond design and the lower part is slot shaped and the gas channels are made in the back side. The shadow-mask replaces the rib wall while the thin glass sheets are used instead of the conventional dielectric layers. So the structure is simplified as a sandwich which includes the front and rear thin glass sheets, the shadow-mask, MgO layers and the exterior electrodes. Moreover, a special vacuum in-line sealing system, which consists of a vacuum chamber, temperature control system and gas filling system, is applied to the fabrication. The panels can be sealed directly in the system without pumping tubes. As an alternative promising application of the narrow-band (NB) UVB source, which can be used for treating skin diseases such as psoriasis2, dermatitis and alopecia areata, the device has the advantages of flexible, addressable and excellent air-tightness. In order to radiate the NB-UVB from the devices, the 312 nm emission phosphors are deposited on the front side of shadow-mask. The UV-transmission of 312 nm can reach about 80% from the phosphor to the outside of a thin alkali-free glass. The experimental results demonstrate that the high content of Xe can be used in the devices and improve both of the emission and efficiency. Furthermore, double-sided radiation can be realized due to the mesh-structure shadow mask.