Dielectric barrier discharge lamp

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.