SU102798A1 - Photoelectric colorimeter - Google Patents

Description

The subject of the invention is a photoelectric colorimeter for measuring the color of radiation of light sources and various transparent and opaque materials in a colorimetric system adopted by the International Commission on Illumination (CIE) in 1931.

For this purpose, photovoltaic cells with light filters were used in known photoelectric colorimeters, resulting in sensitivity curves of photoelectric cells to the curves of specific components X, Y Z of the standard observer of the MKO (Fig. 1). The color measurement process using these colorimeters is reduced to sequentially determining the values of three photocurrents and further calculating the color from known ratios. Colorimeter schemes have also been proposed, in which measurement results are obtained directly as the intersection point of three galvanometer arrows located at the corners of the color triangle.

The accuracy of all these colorimeters is small, since the measurement results depend on the absolute intensity of the measured radiation, which can vary during the measurement, as well as on the linearity of the scale of the used galvanometers. In addition, these colorimeters

Significant inaccuracies result from inaccurate reproduction of the curves of the addition of a standard MKO observer, especially with Crea X, which has two difficultly reproducible maximums. Obtaining values of the relative color components of the radiation of the MKO system from measurements of these colorimeters with noMOHibio is associated with complex calculations.

In the proposed photoelectric colorimeter, instead of measuring each of the photocurrents, their ratio is determined by a zero compensation metric, and the measurement results are obtained through a dot on the standard color chart of the ICT colorimetric system. To facilitate the selection of CBS filters to the X curve, it is selected with a spectral curve having only one maximum within the visible spectrum. In this connection, the new photoelectric co-uurner meter is characterized by high accuracy, speed and ease of measurement.

FIG. 2 shows a printable scheme of the proposed photoelectric colorimeter.

Measured - radiation is sensed by selenium photoelements. Lines 2, 2, and 2.3 with light filters, and curved, which give photocell sensitivity curves to specific

Komioeeit system (A „, Y, Z). Photocells in pairs are connected in two circuits, so that each piece of pph is loaded with the first potentiometer 4, 5, 6, 7, to pins 8, 9, 10, P of which two sensitive zero galvanometers are connected. Instead of four photo cells and two galvanometers depicted in FIG. 2, it is possible to use three or fewer photocells and one galvanometer switched from one compensation circuit to another.

In the process of measurements, the points 9 and / O of the connection of galvanometers remain unchanged, and the moving contacts 8 and u move until zero counts of the galvanometers 12 are obtained. It is easy to show that the distances of the moving contacts of 8 nil potentiometers from the beginning of the potentiometers to the full compensation positions will be proportional to the ratios measured photocurrents.

Two linear indicators 13 and M, whose rotation axes are located at points 5 and 16, are located on the X axis of the color graph, are connected to the moving potentiometer contacts. The color of the measured radiation is obtained directly on the standard color chart of the color coagulation system of the MKO in the form of a point formed by the intersection of two linear indicators in the positions corresponding to zero readings of galvanometers.

To facilitate the selection of a filter reproducing component X, a new curve (Fig. 1) is reproduced in the colorimeter instead of the International X curve (Fig. 1) associated with the A.U.Z curves of the international system with linear ratios and having only one maximum within the visible spectrum.

In order to automate the color measurement process, the moving contacts of the potentiometers can be moved with the help of two electric motors, to the windings — whose excitations — are given enhanced potential differences between the moving and fixed contacts of the potentiometers.

The point of intersection of the indicators in this case can be associated with a writing device, and thus the chromaticity change curve can be automatically recorded on the color graph when measuring sources with time-varying radiation.

Subject invention

Claims (4)

1. A photoelectric colorimeter for measuring the color of the radiation, containing photocells with light filters for producing photocurrents proportional to the color components of the radiation, and a color chart with linear indicators located on it, the intersection point of which determines the color of the radiation, differing in that. that, in order to improve measurement accuracy and obtain measurement results that do not depend on the absolute intensity of the measured radiation, photo cells are included in compensation circuits that measure the ratio of two photocurrents to the third, and the linear indicators are mechanically connected to the moving potentiometer contacts of compensation circuits. 2. Photoelectric colorimeter pop. 1, characterized in that, in order to obtain direct color readings on the standard color graph of the International Colorimetric System (CIE system), the rotation centers of the indicators are located on the X axis of the CIE color chart, and compensation potentiometers are installed parallel to this axis, to obtain a linear tangent connection the angle of rotation of the indicators with the values of the photocurrent relations. 3. Photoelectric colorimeter on PP. 1 n 2, characterized in that, in order to facilitate the selection of a light filter reproducing the X curve of a standard MCO system observer, it is selected with a spectral transmittance curve that has only a maximum in the entire spectral range, and the photocell spectral sensitivity is associated with this light filter with the curves Л, Y, and Z of the MKO system, the linear relations. 4. Photoelectric colorimeter on PP. 1-3, characterized in that, in order to automate its operation, two electric motors are used, moving the moving potentiometer contacts to the compensation position and powered from amplifiers, to the input of which a potential difference between the moving and non-movable potentiometer contacts is applied. TOOAnyj