| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum chuck surely absorbing an object to be absorbed which is to be mounted on a part of an absorption surface by absorption force required for the vacuum chuck. SOLUTION: It is defined that atmospheric pressure is P1 and minimum absorption power required for the vacuum chuck 1 is Fmin. A numerical aperture n which is the ratio of a unit surface area of an absorption pad 2 having a rear side absorbed by a vacuum pump 5 the ultimate pressure of which is Pu and the exhaust efficiency is Se to a total aperture area of a through hole exposed to the unit surface area and the conductance C of the whole absorption pad 2 by many through holes satisfy the shown expression 1. In the vacuum chuck 1 satisfying the expression (1), even when air is leaked from a part of the absorption pad 2 which is not covered with the object to be absorbed, the object to be absorbed is surely absorbed and held by absorption force of Fmin or greater. COPYRIGHT: (C)2011,JPO&INPIT |
