PURPOSE: To eliminate possibility of contamination of a decompression chamber caused by raising of dusts, etc., by oscillating a thin plate formed to cover an opening part in an approximately parallel direction to a surface thereof, applying a dc voltage between a thin plate and a partition and realizing a strong vacuum seal state of an opening part by electrostatic attraction.
CONSTITUTION: One insulation board 1406 is fixed to a chamber wall 1407 and a metallic electrode 1408 is held between both insulation boards 1406, 1409. One electrode of dc power supply is connected to the metallic electrode 1408 and the other electrode of dc power supply is connected to a thin plate 1401. In the process, the thin plate 1401 is attracted by electrostatic power by applying a voltage of around 100V between the electrode 1408 and the thin plate 1401 and vacuum seal is carried out together with an O ring 1411 by the power. A material having elasticity is desirable as the electrode 1409. When one chamber is an ambient pressure, the strength is insufficient and a mechanically strong gate valve, that is, a gate plate 1410 with a specified thickness is used instead of the thin plate 1401.
SHIBATA SUNAO
UMEDA MASARU
