Lens module comprising at least one exchangeable optical element

Abstract

An optical system has a housing with a mount and an opening to a receiving region, the receiving region being located within the housing and including the mount. At least one optical element is inserted into and removed from the receiving region through the opening, and at least one gas supply device provides a flow of gas in the receiving region. An associated method of inserting or removing an optical element into or from a receiving region in a housing is also disclosed.

1 . (canceled) 
     
     
         2 . An apparatus comprising:
 a gas supply;   a gas inlet line;   a gas output device; and   a receiving area to receive gas from the gas output device;   wherein:   the gas supply is arranged to provide the gas to the gas inlet line,   the gas inlet line is arranged to output the gas into the gas output device, and   the gas output device is arranged to output the gas into the receiving area in a laminar flow.   
     
     
         3 . The apparatus of  claim 2 , wherein the gas output device comprises a grating. 
     
     
         4 . The apparatus of  claim 3 , wherein the gas output device comprises a second grating;
 wherein the grating is offset relative to the second grating.   
     
     
         5 . The apparatus of  claim 3 , wherein the receiving area comprises an area within an optical element mount into which an optical element is mounted. 
     
     
         6 . The apparatus of  claim 5 , further comprising an opening in the optical element mount into the receiving area, wherein the opening is through a side of the optical element mount opposite to a side of the optical element mount through which the gas output device outputs gas into the receiving area. 
     
     
         7 . The apparatus of  claim 6 , wherein the optical element is a removable optical element configured to be inserted and removed from the receiving area of the optical element mount via the opening. 
     
     
         8 . The apparatus of  claim 7 , wherein the gas supply is configured to supply gas while the optical element is being removed from the receiving area via the opening. 
     
     
         9 . The apparatus of  claim 7 , wherein the gas supply is configured to supply gas while the optical element is being inserted into the receiving area via the opening. 
     
     
         10 . The apparatus of  claim 2 , wherein the gas output device comprises a bore device, wherein the bore device comprises a plurality of bore holes. 
     
     
         11 . The apparatus of  claim 9 , wherein the gas output device comprises a second bore device comprising a second plurality of bore holes;
 wherein the plurality of bores holes are offset relative to the second plurality of bore holes.   
     
     
         12 . The apparatus of  claim 10 , wherein the receiving area comprises an area within an optical element mount into which an optical element is mounted. 
     
     
         13 . The apparatus of  claim 12 , further comprising an opening in the optical element mount into the receiving area, wherein the opening is through a side of the optical element mount opposite to a side of the optical element mount through which the gas output device outputs gas into the receiving area. 
     
     
         14 . The apparatus of  claim 13 , wherein the optical element is a removable optical element configured to be inserted and removed from the receiving area of the optical element mount via the opening. 
     
     
         15 . The apparatus of  claim 14 , wherein the gas supply is configured to supply gas while the optical element is being removed from the receiving area via the opening. 
     
     
         16 . The apparatus of  claim 14 , wherein the gas supply is configured to supply gas while the optical element is being inserted into the receiving area via the opening.