<p>A gas discharge vessel (GDV) (2) has a gas discharge substance (GDS) emitting electromagnetic radiation (ER) in a vacuum UV range while a lamp operates. On the inner side of the GDV's wall there is a first layer of luminous matter (LOLM) (5) facing the GDS. A second layer of LOLM (4) is excited by UV type A radiation and emits ER in a visible range.</p>
