| 摘要 |
PROBLEM TO BE SOLVED: To eliminate irregurality of main discharge, by cover-forming a corona electrode on a region facing a main discharge space on the outer surface of a dielectric pipe, and obtaining preliminary ionization intensity of uniform distribution. SOLUTION: In a preliminary ionization electrode 2, a metal layer 7 is cover- formed on a region facing a main discharge space, out of the outer peripheral surface of a dielectric pipe 4 into which a rear electrode 3 is inserted. A metal layer 7 is formed in a belt type along the longitudinal direction of the dielectric pipe 4 and constitutes a corona electrode 7 turning to one side electrode of the preliminary ionization electrode 2. An external electrode 8 is brought into contact and electrically connected with the corona electrode 7. When a voltage is applied across the back electrode 3 and the corona electrode 7, corona discharge is started on both end edges 7a, 7b of the corona electrode 7 and progresses to the outer periphery of the dielectric pipe 4. Ultraviolet rays are casted toward a main discharge space. |
