METHOD FOR CHECKING A FILM THICKNESS DURING THE APPLICATION THEREOF BY EVAPORATING IN A VACUUM CHAMBER

摘要

The invention relates to instrumentation engineering and can be used for controlling a film thickness during the application thereof by evaporating in a vacuum chamber. The inventive method consists in controlling the thickness of films of a multi-layer optical coating during the application thereof by evaporating in a vacuum chamber on three ?<SUB>0</SUB>, ?<SUB>1</SUB> and ?<SUB>2</SUB> wavelengths, which satisfy the relationship 1/?<SUB>1</SUB> +1/?<SUB>2 </SUB>= 2/?<SUB>0</SUB>, wherein ?<SUB>0 </SUB>is<SUB/>the reference wavelength<SUB/>for a evaporated film (of a multi-layer coating), in recording the difference of photoelectric signals for the ?<SUB>1</SUB> and ?<SUB>2</SUB> wavelengths, in determining the extremum of a transmittance (reflectance) factor for the third ?<SUB>0</SUB> wavelength <SUB/>and in receiving a signal for interrupting the deposition process when the extremum of a transmittance (reflectance) factor on the wavelength ?<SUB>0</SUB> and the equal-zero difference of the transmittance (reflectance) factors on the ?<SUB>1</SUB> and ?<SUB>2</SUB> wavelengths is simultaneously attained. Said method makes it possible to increase the checking accuracy of the evaporated film thickness.