Abstract: An optical apparatus for a lithography system comprises at least one optical element comprising an optical surface. The optical apparatus also comprises one or more actuators for deforming the optical surface. A strain gauge device is provided for determining the deformation of the optical surface. The strain gauge device comprises at least one optical fiber that maintains polarization.

Abstract: The object of the present invention is to provide board-like molded elements that can be produced in a simple manner, at low cost, and that will be more flexible and possess a more precise standard of quality than can be achieved with conventional methods, and a method for producing said elements. In order to attain this object, a method for producing board-like molded elements made from natural fibers is proposed pursuant to the invention, wherein natural fibers are mixed with bonding agents, the mixture is placed on a molding platform where it may be shaped, after which the elements are bonded, characterized in that the bonding agent is admixed in the form of material elements that at least partially form bonding agents following an activation.