FIELD: instrumentation. SUBSTANCE: process of control over planeness of free surface of liquid near inclined plate is improved by way of use of thermal capillary convection induced by laser beam. While measuring edge angles of wetting portion of laser inducing convection and reflected from free surface of liquid is projected on screen positioned in cross-section of caustic of reflected beam. Corresponding interference picture is viewed on screen. Wetting of inclined plates used in measurement leads to static deformation of free surface of liquid between them having form of cylindrical meniscus. Form of response depends on value and sign of static curvature thanks to property of additivity of dynamic curvature of thermal capillary recess and static curvature of free surface of liquid. In case of unidimensional static curvature of free surface of liquid between plates thermal capillary response from laser beam incident between them has shape of ellipse. EFFECT: elimination of subjectivity factor and automation of high-precision measurements. 4 dwg
