SU1383163A1 - Refractometer - Google Patents

Abstract

The invention relates to optical measurements. The purpose of the invention is to provide the possibility of refractometric studies of multicomponent liquids and to increase the accuracy of measurements. A refractometer for studying liquids contains a radiation source, an illumination and an observation system with an angle measuring system, an input-output element of the radiation into the cell with the liquid under study. The radiation input-view element is made in the form of a hollow ellipsoid of rotation or an elliptical cylinder, with a specularly reflecting inner surface, truncated by focal planes perpendicular to this major axis, and the cuvette is filled in the form of a hemisphere or a circular semi-cylinder and its center (or cylinder axis) combined with his other focus. Illuminating radiation is focused on the surface of the liquid after reflection from the surface of the element. The composition of the liquid under study is determined by its refractive index by measuring the angle of total internal reflection at the liquid – air interface, liquid – film, film – air. A refractometer can be inserted into a flat translucent reflector installed in one of the foci of the radiation input-output element in the plane coinciding with the larger erd axis, which turns the refractometer. meter to inter | ferometer shift with reverse ray path. 1 hp f-ly, 4 ill. (O with 00 with O5 with

Description

one . 13

The invention relates to optical instrumentation, more specifically to optical devices for studying liquids by changing the properties of an illuminating luminous flux reflected on their surface and measuring the critical angle of reflection, and can be applied in chemistry, analysis of pollution of sea and fresh water, and films on their surface. and similar areas x.

The purpose of the invention is to provide the possibility of refractometric studies of multicomponent liquids and to improve the measurement accuracy.

FIG. 1 shows the optical scheme of the refractometer} in FIG. 2 shows an element of the emission radius, an embodiment, continuous with hemispherical grooves in FIG. 3 and 4 - the possible location of the liquid and the film on it and the course of the rays with a smaller than the liquid, the refractive index

film substances. :

The refractometer consists of a lighting system 1 comprising a series of radiation source 2, which can be a laser, a capacitor 4, a diaphragm 4, a mirror 5 and a lens 6, a measurement input-output element 7, a cell 8 and an observation system 9 including an angular scale 10, Mirror 11 and the eyepiece p 12.

The device works as follows.

The radiation from the source 2 is focused into the focus (focal line) of the element a 7 and after a series of reflections it is again focused in another focus of the element.

that coincides with the center of the cuvette 8 and the surface of the liquid under study. At the focal point, the rays incident on the surface of the liquid at the angle of total internal reflection (PWR) and large are reflected from its surface and, after a series of reflections, fall on the scale 10 of the system 9. The coefficient is determined by the measured PWI angle. Cycle of refraction of the liquid. If the liquid in the cuvette is covered with a film of a LAR 5 th liquid, then the homocentricity of the rays during air defense is violated. FIG. 4 shows the possible location of the liquid and film on it and the course of the rays.

at a lower than the liquid, the refractive index of the substance of the film. In this case, on the cabinet 10, two areas with different illumination are observed.

0

five

0

five

0

five

formed by the rays at the air defense at the border of liquid - film, film - air. The magnitude of the bias-centered beam shifts depends on the refractive index of the film substance and the measurable parameters: film thickness, liquid refractive index, and structural data of element 7 and the observing system 9. The film refractive index is determined from the magnitude of the bias.

The following can be entered into the refractometer: a flat translucent reflector 13 installed in one of the focuses

of the radiation input-output element coinciding with its major axis.

FIG. 2 shows the course of the rays in a refractometer with a translucent reflector. Such a refractometer is a reverse-shear interferometer with a ray path. When the reflector is tilted in the plane of the figure, an interferogram is formed with the interference of rays reflected from the liquid-film surface and film-air, which expands the possibilities of research and increases the measurement accuracy.

The advantage of the refractometer is the expansion of the range of the studied media and an increase in the measurement accuracy by the count of the bands on the shear interferogram.

Claims (2)

1. A refractometer containing illumination and observation systems optically coupled to a radiation input / output element in a cuvette for the test liquid, characterized in that, in order to preserve the possibility of refractometric studies of multicomponent liquids and to improve the accuracy of measurements, the radiation input / output element made in the form of a hollow ellipsoid  rotation or an elliptical cylinder with a specularly reflecting inner surface truncated by focal planes perpendicular to its major axis; and the cuvette is made in the form of a hemisphere or a circular half cylinder and its center or axis of the cylinder is aligned with its other focus or focal line. 2. A refractometer according to Claim 1, characterized in that a flat translucent reflection is introduced into it. 1 Fi.g Figz Fi.C