A dielectric barrier discharge (DBD) lamp is disclosed. The DBD lamp
comprises a discharge vessel, which encloses a discharge volume filled
with discharge gas. The discharge vessel further comprises a phosphor
layer within the discharge volume. The discharge vessel comprises an
outer tubular portion having an internal surface, and an inner tubular
portion having an outward surface. The outer tubular portion surrounds
the inner tubular portion. In this manner, a substantially annular
discharge volume is enclosed between the outer tubular portion and the
inner tubular portion. The inner tubular portion comprises a multitude of
protrusions around its circumference. The protrusions extend into the
substantially annular discharge volume. A first set of interconnected
electrodes and a second set of interconnected electrodes are also
provided. The electrodes are isolated from the discharge volume by at
least one dielectric layer, and at least one of the dielectric layers is
constituted by the wall of the inner tubular portion.