SU1485034A1 - Spectral reflection and transmission factor measuring method - Google Patents

Description

The invention relates to the field of spectral instrumentation and can be used in measuring devices, in particular in spectrocolorimeters. The purpose of the invention is to simplify the measurements without compromising accuracy. This is achieved by combining the channels of the comparative path into groups according to a given accuracy of signal registration. 1 il.

The invention relates to spectral instrumentation and can be used in measuring devices.

The purpose of the invention is to simplify the method of measuring the spectral reflectance or transmission coefficients without impairing the accuracy.

The drawing shows a device for implementing the method.

The source of 1 pulsed radiation is placed in the integrating sphere 2, which has a measuring hole 3. These elements, together with the lens 4, are integrated into a device for illuminating the sample 5 and observing it. Lens 4 transmits an image of sample 5, the spectral reflection coefficients of which are to be measured, to the working input 6 of a polychromator, consisting of optical fibers 7 and interference filters 8. Comparative input 9 receives radiation reflected from the ball wall. The screen 10 prevents direct rays from the sample 5 and the source 1 from entering the comparative input. The photodetectors 11 are connected to the measuring device 12. The transparent sample 13 to be examined is installed in front of the entrance 6 of the polychromator.

Pulsed spectrocolorimeter works as follows.

The pulsed radiation source 1 illuminates the sample under study 5, which is pressed against the measuring hole 3. The radiation reflected from the sample under study 5 or transmitted through the transparent sample 13, with the help of lens 4 is fed to the working input 6 of the polychromator. The polychromator is a fiber-optic converter (light guide) 7 with one measuring input 6 and one comparative input 9 and a set of outputs on which interference filters 8 are installed. The radiation from the sample (input 6) and from the source (input 9) is decomposed into a spectrum, falls on the photodetectors 11, where it is converted into a photoelectric signal, which enters the measuring device 12. For each of the channels of the measuring path, the latter calculates the ratio between the signal of the measuring path to sig the combined channel of the comparison channel, which included the spectral interal of this measuring channel. A comparative channel contains one or more photodetectors, each of which

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optically connected with certain groups of polychromator outputs.

To form the output groups of the comparative path polychromator, two consecutive measurements of the signal values величин7 are carried out on the selected lamp ₍ ί and in each kth channel. From the measurement results,

One of the channels is selected, for example, the first one, and the fulfillment of inequality is determined relative to it.

ι ^ -Α'κδ, where / = 2, ..., N.

Channels for which the inequality is satisfied are combined into the first group. From the channels that are not included in the first group, choose one of the channels and determine the fulfillment of inequality relative to it and form the second group. Similarly form the third and subsequent groups.

Since in the measured signals (7, there is a random component, to increase the reliability of combining the outputs of the comparative path of the polychromator into groups, the number of consecutive measurements is selected in accordance with the methods of mathematical statistics.

The combination of several spectral intervals into one of the M photodetectors of the comparative path of radiation fluxes leads to a significant reduction in the measurement volume due to a decrease in the number of photodetectors, especially in those cases when measurements are required on a large number of spectral intervals. At the same time, the random measurement error caused by a change in the radiation energy of the lamp from impulse to impulse is reduced due to the grouping of comparative channels to 0.1—0.2%.

Claims (1)

Claim A method of measuring the spectral reflection and transmission coefficients, including the illumination of the sample under study by pulsed radiation, measurement of the reflected or transmitted through the sample radiation in the N spectral channels of the measuring path, measurement of the source radiation in the channels of the comparative path and determination of the ratio of the signals of the measuring and comparative paths, in order to simplify the process without deteriorating accuracy, before measurements were recorded signals ί7, _Ί and (/ - ₂ in the ith channel of the measuring path Where i = 1, 2 ..., Ν, at two successive radiation pulses are calculated from the measured _ίΖ (7, m - (7,2 signal values parameter l, = —y--, (7, ·, combine the channels of the comparative path corresponding to the spectral intervals of the measuring path for which the inequality is fulfilled | K - / ^ | ^ δ, where / = 1,2, ..., M is the group number of the combined channels of the comparative path; δ is a parameter defined by measurement error and the value of M; ί - (g + 1), ..., N for the first from M groups, and for subsequent groups does not take values that are included in previous groups, and the spectral reflection or transmission coefficients are determined by the ratio of the signal of one of the channels of the measuring path to the signal of the / th group of channels of the comparative path, which includes the spectral interval of the measuring path. 1485034