| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum chuck wherein the fallout of a work caused by the vacuum break of the whole of its sucking pattern is prevented and failure caused by the damage of the work or by the positional discrepancy of the held work can be eliminated. SOLUTION: In the vacuum chuck 3, there formed is a sucking pattern 21 opened to the surface of the chuck 3 which comprises a plurality of annular grooves 22 provided in the form of concentric circles and radially extended communication grooves 23 for communicating with the annular grooves 22. Further, barrier portions 24 are provided in the predetermined places of the sucking pattern 21 for opening to the surface of the chuck 3 each of which has a larger flow-passage resistance than its before and after portions. Each barrier portion 24 is formed of a throttle portion wherein the sectional area of a groove is reduced. COPYRIGHT: (C)2004,JPO |
