Rectangular indicator panel for vehicle licence plate - has transparent symbols which are partially filled with dense opaque liquid

摘要

The indicator panel, having a rectangular shape in front elevation, is typically for use as a motor vehicle licence plate. The symbols mounted on the plate are hollow and are partially filled with a liquid which is visible through the transparent sides of the symbols. In one design a flat backing plate with a stiffened rim (4) attached around the border. This border retains the symbol members (23). The liquid has a high specific weight and is retained in a vacuum enclosed environment, sealed by high frequency welded joints. The main surface area (21) of the indicator panel is a suitable colour to contrast with the symbols.