METHOD MEASURING OPTICAL THICKNESS OF PLANE-PARALLEL CLEAR OBJECTS Russian patent published in 2000 - IPC

FIELD: measurement technology, interference methods of measurement of optical thickness of plane-parallel objects and layers. SUBSTANCE: optical thickness of plane-parallel clear objects is measured by way of direction of beams reflected from surfaces of object on to double-beam interferometer, biprism or Fresnel bimirror. Two spatially-coherent beams propagating in one common direction with small angle one relative to another are formed and position-sensitive multielement photodetector is placed in region of superimposition of beams. EFFECT: simplified interference picture thanks to formation of three non-localized zero interference bands that leads to increased productivity of measurements. 3 cl, 2 dwg