Patent ID: 7307688

Claim:
A lithographic apparatus arranged to transfer a pattern from a patterning device onto a substrate, the apparatus comprising: an optical element, and at least two clamping assemblies constructed and arranged to clamp said optical element, said clamping assemblies each comprising a first clamp with a first clamping surface in contact with a first surface of said optical element and a second clamp with a second clamping surface in contact with a second surface of said optical element, said second surface being on a side of the optical element opposite said first surface; a support connected to said first clamp and said second clamp so that said first and second clamps are positioned facing each other with the optical element disposed between the first clamp and the second clamp; a first guide constructed and arranged to connect said first clamp to said support and to allow said first clamp to move in a first direction substantially perpendicular to said first surface of said optical element and to constrain said first clamp against movement in directions perpendicular to said first direction, even when said first clamp is forced against said optical element; and a plurality of locking members constructed and arranged to force said first clamping surface of said first clamp against said first surface of said optical element, and said second clamping surface of said optical element against the opposing second surface of said second clamp.