Apparatus for the projection of fringe-like light patterns

An apparatus for generating a set of N given fringe like intensity distributions I.sub.k (y), wherein I denotes a local intensity depending only on the y-direction, while in the x-direction the intensity is constant, and k is an integer between 1 and N denoting a number of the given individual intensity pattern, comprising:

• a mask assembled from non-stripe shaped subareas, a transparency or a luminance of each of said sub-areas being controllable between bright and dark to form a given mask pattern, said sub-areas being constructed by drawing a graph of the N desired functions I.sub.k (y) within one single diagram,
• the superposition of the different graphs forming a mosaic of sub-areas, the graphs becoming the boundaries of the given sub-areas,
• said subareas being controlled between bright and dark for the projection of an intensity distribution I.sub.k (y), by switching all sub-areas located under the graph of I.sub.k (y) to the bright state, and
• an astigmatic imaging system for projecting an astigmatic image of said given mask pattern, said astigmatic imaging system including a cylindrical lens for integrating radiation received from said mask in one spatial direction and converting the given mask pattern of light and dark sub-areas into a fringe-like pattern, the fringe-like pattern projected by said astigmatic imaging system being variable by varying said given mask pattern of light and dark sub-areas of said mask.