Visual display unit illumination

摘要

A method of adapting a visual unit having a first screen (10) in a first focal plant by the addition of one or more at least partially transparent display screens (20) at least partially overlapping said first screen (10) and located in focal planes distinct from said first focal plane, characterised in that an at least partially transparent emissive layer (21) is provided between said first screen (10) and at least one said additional display screen (20).