Flat coplanar-discharge lamp and uses of same

A flat discharge lamp transmitting radiation in the ultraviolet or visible spectrum, comprising:

• first and second substantially flat glass elements substantially parallel to each other and defining an internal space filled with gas, the first or second glass elements being made of a material that transmits the radiation;
• at least one first electrode and at least one second electrode that are supplied with an AC voltage, the first and second electrodes being associated with one or more main faces of the first glass element, the first and second electrodes being elongate and substantially parallel to one another, and forming an interelectrode space of a substantially constant width d1 between each adjacent electrode;
• at least one third electrode at a given potential, associated with a main face of the second glass element and at least partly occupying, in projection, each interelectrode space;
• and
• at least one fourth electrode associated with a main face of the second elongate glass element and substantially parallel to the third electrode,
• wherein the third and fourth electrodes are at different potentials and are supplied with an AC voltage,
• wherein projections of the third and fourth electrodes occupy at least 50% of each of the interelectrode spaces
• wherein the first and second electrodes are made of transparent conducting films or are overall transparent.