Abstract: A high conductivity particle filter provides a flow path to subject a fluid stream to a series of turns. The turns require an abrupt directional change for the fluid stream. Traps are positioned in proximity to the turns to capture particles, which have greater inertia than the fluid. The flow path may be a spiral or a series of parallel paths. A cross sectional area of the flow path may be progressively decreased to increase flow velocity and particle inertia.

Abstract: The present invention relates to a multilayer phosphor layer system for an electroluminescent display. The phosphor layer according to the invention is comprised of several superimposed host matrix material layers (7) and interposed activator-containing doping layers (9, 10). The activator-containing doping layers (9, 10) are extremely thin, whereby disturbance to crystal growth of the host matrix material at the doping layer (9, 10) is avoided. The activator-containing doping layer (9, 10) can be comprised of an actual activator layer (10) and a matching layer (9) adapted between said host matrix material layer (7) and said actual activator layer (10), whereby said matching layer (9) improves the matching between said host matrix material layer (7) and said actual activator layer (10). By virtue of the layered structure, it is possible to use such host matrix/activator material pairs that otherwise would be useless due to their poor efficiency or weak light emission.