In Variation Example 1 shown in FIG. 7 and Variation Example 2 shown in FIG. 8, a protrusion (a protrusion 92 in Variation Example 1, a protrusion 94 in Variation Example 2) is provided on the dielectric substrate 12 between the high-voltage electrode 14 and the blowout outlet 30, making the dielectric substrate with the protrusion that separates the high-voltage electrode 14 from the low-voltage electrode 20. Specifically, in Variation Example 1, the protrusion 92 is provided at the end of the dielectric substrate 12 (directly above the blowout outlet 30). In Variation Example 2, the projection 94 is provided to be in contact with the end of the high-voltage electrode 14 that is closest to the blowout outlet 30. It is also possible to provide the protrusion 92 and the protrusions 94 simultaneously.
The protrusions 92 and 94 can be made of a material exemplified as that of the dielectric substrate 12; however, the protrusions 92 and 94 may be made of the same material or different material from that of the dielectric substrate. The protrusions 92 and 94 may be integrally formed with the dielectric substrate 12 or may be attached thereto as a separate component.
