The approach presented here provides a membrane unit (105) comprising micro-optical structures (115), which comprises a wafer (110) as carrier basis of the micro-optical structures (115), an intermediate substrate (300) connected to the wafer (110), and a carrier (130) connected to the intermediate substrate (300), wherein the coefficients of thermal expansion of the wafer (100), of the intermediate substrate (300) and of the carrier (130) are dimensioned such that a coefficient of expansion of the carrier (130) is greater than a coefficient of expansion of the intermediate substrate (300) and the coefficient of expansion of the intermediate substrate (300) is greater than or equal to a coefficient of expansion of the wafer (110).