Patent ID: 7859641

Claim:
An optical element module comprising: an optical element, an optical element holder and a first contact element; said optical element having a first coefficient of thermal expansion; said optical element holder holding said optical element via said first contact element and having a second coefficient of thermal expansion, said second coefficient of thermal expansion being different from said first coefficient of thermal expansion; a first contact point being formed on a first module component, said first module component being one of said optical element and said optical element holder; said first contact element having a second contact point and a third coefficient of thermal expansion; said first contact point, at a first temperature situation, contacting said second contact point at a first location; said first contact element contacting a second module component at a second location, said second location, at said first temperature situation, being located at a first contact location distance from said first location; said second module component being different from said first module component and being one of said optical element and said optical element holder; at least one of said third coefficient of thermal expansion and said contact location distance being selected such that, at a given second temperature situation different from said first temperature situation, a thermally induced modification in the size of said first contact element with respect to said first temperature situation compensates for the difference between said first coefficient of thermal expansion and said second coefficient of thermal expansion such that, at said second temperature situation, there is substantially no shift between said first contact point and said second contact point, wherein at least one gravity compensation arrangement is provided; said gravity compensation arrangement being held by said optical element holder and contacting said optical element to exert a supporting force onto said optical element; said supporting force substantially corresponding to the gravitational force acting onto said optical element.