Alternative term: Flash Panel (U.S.A.)
A prismatic lens which may be of dioptric elements only, or may include both dioptric and catadioptric elements, all mounted in one rigid supporting frame. Such a panel may be symmetrical or asymmetrical according to requirements. One or more panels form an optic.
(Figs. 10 and 17)
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM