Patent ID: 7034319

Claim:
An electron beam irradiation apparatus comprising: a support section for supporting an electron beam irradiation subject to be irradiated with an electron beam; an electron beam irradiation head opposed to said electron beam irradiation subject and spaced from the subject by a minute space during operation of the apparatus, said electron beam irradiation head having: an electron beam emission hole allowing irradiation of said electron beam irradiation subject by the electron beam passing through the electron beam emission hole; a first ring-shaped gas suction groove and a second ring-shaped gas suction groove formed in a surface of said electron beam irradiation head facing said electron beam irradiation subject around the electron beam emission hole and around an electron beam path passing through the electron beam emission hole, and exhaust means coupled to said electron beam path and said ring-shaped gas suction grooves for holding said electron beam path in a high-vacuum state; a static pressure flotation configuration comprising static pressure means including an opening formed in the surface of said electron beam irradiation head and formed annularly around said ring-shaped gas suction grooves and said electron, beam emission hole, including a ventilation pad filling up the opening of the static pressure flotation means, and including a compressed gas path coupled to the opening of the static pressure flotation means; and driving means for rotating said electron beam irradiation subject around a center axis of a plate surface of said support section and moving in a straight line direction along a plane perpendicular to the rotation center axis, wherein: said ring-shaped gas suction grooves are disposed around said electron beam emission hole taken as a center with the first ring-shaped gas suction groove being closer to said emission hole than said second ring-shaped gas suction groove and the nearer a ring-shaped gas suction groove of said ring-shaped gas suction grooves is to said center, the higher a degree at which the respective ring-shaped gas suction groove is exhausted; W 1 >W 2 , where W 1 is an opening width of said first ring-shaped gas suction groove and W 2 is an opening width of said second ring-shaped gas suction groove; 2.5 mm≦D 1 ≦5 mm and D 2 <W 1 , where D 1 is a distance between said first ring-shaped gas suction groove and said electron beam emission hole and D 2 is a distance between said first ring-shaped gas suction groove and said second ring-shaped gas suction groove; and the minute space between said electron beam irradiation head and said electron beam irradiation subject is held by said static pressure flotation configuration during operation of the apparatus.