INTERFEROMETRIC DEVICE TO MEASURE PHYSICAL PARAMETERS OF CLEAR LAYERS ( VERSIONS ) Russian patent published in 1999 - IPC

FIELD: measurement technology, contact-free measurement of thickness and refractive index of clear layers. SUBSTANCE: proposed device can be used for continuous contact-free test of thickness of polished glass at " hot " stages of its production. Developed device makes it feasible to increase precision of measurement of physical parameters of clear layers under conditions when measured layer or its environment are under effects of high or low temperature, vibrations, heavy electric and magnetic fields or other factors that hinder operation of precision measurement devices. With this in mind interferometric device incorporating source of coherent light, modulator of optical path, beam splitter and photodetector in inserted in agreement with first version with mobile semitransparent mirror and length of optical fiber. Length of optical fiber is positioned between beam splitter and measured layer. End of optical fiber is optically coupled to measured layer. In accordance with second version of design of device there is inserted second beam splitter optically coupled to modulator of optical path and additional mobile mirror, length of optical fiber is inserted between beam splitter and measured layer whose end is optically coupled to measured layer. Interference picture is formed in plane of photodetector thanks to reflection from front and rear surfaces of layer. Constancy of product of thickness of measured layer by its refractive index can be maintained by results of analysis of Fourier spectrum of photoelectric current. EFFECT: increased precision of measurement of physical parameters of clear layers. 5 cl, 5 dwg