The present invention relates to a nozzle assembly for an injector that enables production of high quality injection products by effectively exhausting gas in a molten plastic flowing at a high speed. The head may be a laterally extended foam head that is non-abrasive, freeze resistant, and durable. The conveyor moves in traversing motion across the frame to distribute concrete. According to the invention it is therefore proposed that, in the inactive region, the surface of the multilayer actuator has a pattern that is produced by erosions interrupting the surface, and that the base metallisation is deposited exclusively on the surface left by the pattern. The tunnel barrier comprises magnesium oxide. Liquid crystal material is provided within the LCD panel.