SU940018A1 - Two-beam photometer - Google Patents

Description

The invention relates to photometry and can be used for precision and express measurements of the reflection and scattering coefficients of various objects. Two-beam photometers are known, based on a comparison of radiation fluxes, one of which passes. through the test medium 1} Lack of photometers - low measurement accuracy. The closest in technical essence to the present invention is a two-beam photometer containing a radiation source and a beam splitter installed along the luminous flux, a measuring and control channels made according to the auto-scheme and for both channels a photodetector 2j. The disadvantage of the known photometer is the low measurement accuracy, due to the measurement of the reflection coefficient of the divider when the angle of incidence of the radiation in the measuring channel changes. The purpose of the invention is to improve the accuracy of: measurements. This goal is achieved by the fact that in the device containing the radiation source and installed along the luminous flux, a beam splitter, measuring and control channels made according to the autocollimation scheme, the common for both channels of the photoreceiver, an additional beam splitter is inserted between the beam splitter and the photoreceiver, identical to the first beam splitter , while the normals to the beam-splitting faces of the beam splitters lie in the same plane, and the angle between the beam-splitting faces is equal to twice the angle of incidence of the radiation on the first vetomaker On fmg. 1 and 2 are given functional diagrams, variants of a two-beam photometer. -.

39th

The photometer contains a radiation source 1, a photodetector 2, a beam splitter 3 measuring and control 5 channels, mirrors 6 and 7, an additional beam splitter 8.

The normals to the beam-splitting beam splitters 3 and 8 lie in the same plane, and the angle between the beam-splitting faces is equal to the double angle of incidence of the radiation on the first beam splitter.

The photometer works as follows.

The radiation from source 1 is transmitted to the beam splitter 3, and is split into two beams of measurement k and control 5 channels. Reflecting from mirrors 6 and 7, the radiation passes successively through the beam splitter 3 and 8 to the photodetector 2. When introduced into the measuring channel of the object under study, misalignment of the angle of incidence to beam splitter 3 causes a change in its reflection coefficient. A systematic measurement error occurs. The latter is compensated for by an additional beam splitter, at which the angle of incidence of the radiation varies by the same magnitude, but with the opposite sign. Thus, increasing the reflection on one beam splitter leads to a decrease in reflection on the other beam splitter, and since the radiation enters the photodetector, the passage of both beam splitters in series, then

84

There is practically no dependence of the luminous flux on the de-alignment.

The use of the present invention allows to improve the accuracy of dual-beam photometers.

Claims (2)

1.Fuks-Rabinovich L.I., Epifanov M.V. Optoelectronic devices. L., Mechanical Engineering, 1979, p. Sic 2. The UK patent number 1387b07 cl. G 01 N 21/00, published 1978 (prototype). / g A) ( J / L figl