| 摘要 |
<p>A discharge tube arrangement for use as a light source includes a discharge tube (20) made of a light-transmissive dielectric material and containing a fill. An excitation device for exciting surface waves in the discharge tube (20) comprises an r.f. power generator (34) and a launcher (22). The launcher (22) is formed as an inner tube (26), an outer tube (28) coaxial with the inner tube (26) and first and second end walls (30, 31), at least one of the first and second end walls (30, 31) having an aperture for receiving the discharge tube (20). A launcher gap (32) extends axially from a first end of the inner tube (26) and there is also a further gap (33). The outer tube (28) and the first and second end walls (30, 31) form an unbroken electrically conductive path to provide an r.f. screening structure around the inner tube (26).</p> |
