Abstract: In a flow deflector structure for an intake air duct of an internal combustion engine which includes a housing with air inlet and outlet openings arranged at a predetermined angle with respect to each other for redirecting air flowing through the deflector structure and with flow guide vanes curved according to the flow direction change provided by the flow deflector structure, the housing has a flow cross-section which is larger than the flow cross-section of the inlet and outlet openings and a side wall opening with a cover to facilitate forming, or insertion of the guide vanes in the housing.

Abstract: The invention relates to an improvement for a wafer mounting table particularly for use in photolithographic apparatus for processing wafers comprising a compact mounting block made of glass-ceramics which has two neighboring back supports limiting two sides of a top face of said mounting block. The top face is provided with at least three studs for supporting a wafer to be processed. The sides of the back-supports facing away from said top face are provided with an elongated horizontally extending silvered area each, which is in opposition to a laser path measuring system each. The laser beams of said laser path measuring system define a plane which coincides with a projection plane of a projection lens being provided in opposition to a wafer mounted on said studs. Means are provided for substantially eliminating departures of the silvered areas from a straight plane. Further means are provided which enable a quick adaption of the laser mount for wafer charges having different thicknesses or diameters.