| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem in which a sash bar of an irradiation window has been deformed by irradiation with an electron ray, a wrinkle is generated in a thin film accompanied by the deformation of the sash bar, and if the wrinkle is repeatedly generated, durability of the thin film is reduced to make a life of the thin film shorter.SOLUTION: An irradiation window 17 of an electron ray irradiation device 3 includes a thin film 22 transmitting an electron ray E, and the thin film 22 is supported from an inside of a vacuum chamber 21 by many sash bars 25A. On a rear side of each of sash bars 25A, a slender shield member 26A is provided to be associated with each of sash bars 25A, and maintain an interval. When the electron ray E is radiated outward from the inside of the vacuum chamber 21, each shield member 26A prevents each sash bar 25 from being irradiated with the electron ray E. After the electron ray E radiated outward from the inside of the vacuum chamber 21 passes through an opening 26 between respective shield members 26A and an opening 25 between respective sash bars 25A, the electron ray E passes through the thin film 22 and a polyethylene terephthalate bottle 2 outside the vacuum chamber 2 is irradiated with the electron ray E. Since the electron ray E can prevent the sash bar 25A from being deformed by a thermal expansion, a generation of a wrinkle in the thin film 22 supported by the sash bar can be suppressed, and reduction in durability of the thin film 22 can be prevented. |
