This paper introduces a method for the measurement of stress of thin film. In this method a long focal distance microscope is used and deformation of the thin film on thin glass sheet is observed. Basic structures of a practical device

measuring principle and main means for improving the measurement accuracy are described in detail. Finally

experimental results showing changes of the stresses for ZnS

MgF

2

and ZnS-MgF

2

films along with film thicknesses in various vacuum and evaporation velocity rates have been gain.