An electroluminescent optical indicating device

摘要

A device for displaying the roll of a ship, e.g. for a helicopter landing platform, comprises one set 36 of electroluminescent panels, illuminated progressively, indicating the roll angle, and a second set 38 of electroluminescent panels, illuminated selectively, to indicate the horizontal, the panels being mounted on the ship, e.g. on a hanger wall, and being activated by murcury switches 15 (see Division H2] mounted perpendicularly to the roll axis.