SU1601512A1 - Method of checking quality of optical system - Google Patents

Abstract

The method of quality control of optical systems, which consists in forming a spatially periodic signal of zero frequency, passing it through the system, recording the amplitude of the signal, changing its frequency to the maximum, recording the spectrum of the amplitudes of the signals, and determining the quality of the system the purpose of control is also dispersed systems, the frequency of the signal amplitude remains constant in the amplitude spectrum of the signals and the value of the zero and fixed frequencies is measured by the value of the signal amplitude ratio ie the system parameters.

Description

The invention relates to measuring technique and can be used, in particular, to control dispersed systems, for example, determining particle size, their concentration, etc.

A known method for measuring the parameters of a dispersed system, which involves exposing it to a beam of coherent electromagnetic radiation, recording by scanning the instantaneous intensity distribution in the scanning direction, and processing the results of measured | d, consisting in the study of the spectrum of spatial intensity fluctuations p.

The disadvantage of this method is that it has insufficient:

the accuracy of determining particle sizes, the measured range of which is within the range of 1,200-300 microns, and the low accuracy of determining the concentration of particles in a dispersed system.

The closest in technical essence and effect achieved to the invention is the method of quality control of optical systems, which consists in forming a spatially periodic signal of zero frequency, passing it through the system, registering the amplitude of the signal, changing its frequency to the maximum, registering the spectrum of amplitudes of the signals and determine the quality of the system 2.

This method does not allow control of dispersed systems.

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about sd

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The purpose of the invention is to control also dispersed systems.

To achieve this goal, the frequency amplitude of the signal amplitude remains constant in the amplitude spectrum of the signals and the magnitude of the ratio of the signal amplitudes is zero and; fixed frequencies are judged on the system parameters,

; FIG. 1 shows a block diagram of a device implementing the method} in FIG. 2 - graphs of functions characterizing the amplitude of a spatially periodic signal.

I The method is carried out using a device consisting of an electromagnetic radiation source 1, which is fed to the shaper 2 of a spatially periodic signal with a zero spatial frequency, m | this, functionally connected with Iboc 3, changes in the spatial frequency and the unit (movement , with shaper 2 is connected by a pen | emitting generated radiation unit 5. Transmitting block 5 directs the radiation to the dispersed system 6 under investigation, behind which there is a recording block 7 whose output is connected with the block 8, in which the signal is amplified and: detected.

; The method is carried out as follows.

; From the source 1, a beam of electromagnetic radiation arrives at the shaper 2 of a spatially periodic signal, where a signal with zero spatial frequency is formed. The signal is passed through the transmitting unit 5 and system 6 and the value of the amplitude of the signal with zero spatial frequency, i.e., with a signal period equal to infinity, is fixed in the plane of the registering unit 7, then the spatial frequency is changed using block 3 to determine the maximum value which is selected depending on the particle size range that is present in the dispersed system under test.

After the passage of a spatially periodic signal with a change of frequency with a spatial frequency through the dispersion system under study b is recorded by block 7, the amplitude of the signal at different spatial

0

five

0

five

0

five

0

five

0

five

frequencies by scanning, which is carried out by moving a spatially periodic signal perpendicular to the direction of propagation of electromagnetic radiation. This scan is necessary in order to convert the spatially periodic signal into an electrical signal by modulating the receiving element (there is no block in Fig. 1) of block 7.

After registration, a spatially periodic signal converted into an electrical signal is processed in block 8 by amplification and detection, and then reproduced as an amplitude spectrum of a spatially periodic signal that is functionally dependent on the frequency of the signal.

Information about the dispersed system is obtained by analyzing the nature of the change in the amplitude spectrum of a spatially periodic signal as a function of the spatial frequency, in particular, in relation to the amplitudes of the zero and fixed frequency signals, or by analyzing the nature of the change in the spatial distribution. intensity in the plane of the receiving element of block 7 based on

i (x) coH (),

where X is the coordinate in the plane of the receiving element;

 - a function that characterizes

the form of a spatially periodic signal in the plane. ti receiving element; H (v) is the function characterizing the amplitude of the spatially periodic signal, t, e, is the spectrum of the amplitudes of the cosOx signal in the plane of the receiving element, depending on the spatial frequency. This function is

spatial spectrum indicatrix

dispersion of the investigated dispersion

system.

For a monodisperse system, the function

H {) is equal to

HQ) exp -2 J dva Z

 V P,

: :( agssos - - - x

12

4a

where dv is the volume concentration of particles in the dispersed system, part / µm j a is the radius of the particle; Z is the thickness of the dispersed system layer. Topics;

7 - radiation wavelength. From the expression (1) it follows that

limH () expC-tdva Z) (2) - o

limH () exp (-2il dva Z), (3)

where expression (2) characterizes the value of the function H (y) at zero spatial frequency.

Expression (3) characterizes the value of the function BUT) at a fixed spatial frequency

  .

7

16015126

First, the radius a is determined from the plot of the recorded function HQ) based on the expression (3) from which

5 it follows that with the function

-1 () does not change, i.e. is constant and goes to the linear

plot at the moment when) -.

10 L

Therefore, according to the graph of the recorded function H (), the frequency at which AND {) becomes constant, i.e. parallel to the x-axis, then

but

 BUT

W

20

Then, the concentration of particles is determined by dividing expression (2) by expression (3) followed by substituting into the resulting expression the values of Z, and the values of the radius and the particle

25

dv 1p (

H (0)

but

 BUT

W

Then, the concentration of particles is determined by dividing expression (2) by expression (3) followed by substituting into the resulting expression the values of Z, and the values of the radius and the particle

25

dv 1p (

H (0)

30 Thus, the introduction of the operation

Since the values of Z and known, fixing the frequency with which the signal amplitude remains constant, together with the known sequence of operations allows the method for controlling the dispersion to use the function BUT) is recorded on a reproducing unit (not shown), the concentration dv and particle size radius a is determined as follows:

35

systems.

 fixing the hour and the signal of the aggregate by the order

35

systems.

I rel. ee

2

b

7

go

iS

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Claims (1)

A METHOD FOR MONITORING THE QUALITY OF OPTICAL SYSTEMS, which consists in forming a spatially periodic signal of zero frequency, passing it through the system, recording the amplitude of the signal, changing its frequency to the maximum, recording the spectrum of amplitudes of the signals and determining the quality of the system, characterized in that control also of dispersed systems, the frequency of the signal amplitude remains constant in the amplitude spectrum of the signals, and the magnitude of the ratio of the amplitudes of the signals is zero and fixed frequencies about system parameters. the accuracy of determining particle sizes, the measured range of which is in the range of 1 200 - 300 microns, and the low accuracy of determining the concentration of particles in a dispersed system. The closest in technical essence and the achieved effect to the invention is a method of controlling the quality of optical systems, which consists in forming a spatially periodic signal of zero frequency, passing it through the system, recording the amplitude of the si-nal, changing its frequency to the maximum, recording the amplitude spectrum signals and determine the quality of the system £ 23. This method does not allow to control dispersed systems. 51) ,,,, 1601512 A1 3 1601512 four The purpose of the invention is to control also disperse systems. To achieve this goal, the frequency of the signal amplitude remains constant in the amplitude spectrum of the signals, and the magnitude of the ratio of the signal amplitudes of zero and fixed frequencies determines the system parameters. FIG. 1 shows a block diagram of a device implementing the method} in FIG. 2 - graphs of functions characterizing the amplitude of a spatially periodic signal. The method is carried out using a device consisting of an electromagnetic radiation source 1, which is supplied to a spatial periodic signal generator 2 with a zero spatial frequency, functionally connected to the spatial frequency change unit 3 and a signal movement unit B, and the generated radiation unit 5 is connected to the generated signal. The transmitting unit 5 directs the radiation to the dispersed system 6 under investigation, behind which there is a recording unit 7, the output of which is connected to the processing unit 8. heel information, wherein the signal is amplified and detected ί. ί The method is as follows. From the source 1, a beam of electromagnetic radiation arrives at the shaper 2 of a spatially periodic signal, where a signal with a zero spatial frequency is formed. The signal is passed through the transmitting unit 5 and the system 6 and the amplitude of the signal with zero spatial frequency is fixed in the plane of the recording unit 7, i.e., with a signal period equal to infinity, then the spatial frequency is changed using block 3 to determine the maximum value is chosen depending on the range of particle sizes that is present in the dispersed system under test. After passing a spatially periodic signal with varying spatial frequency through the dispersed system 6 under study, the unit 7 records the values of the signal amplitudes for various spatial 10 15 20 25 thirty frequencies by scanning, which is carried out by moving a spatially periodic signal perpendicular to the direction of propagation of electromagnetic radiation. This scan is necessary in order to carry out the conversion of a spatially periodic signal into an electrical signal by modulating the receiving element (in Fig. 1 is absent) of block 7. After registration, the spatially periodic signal converted into electrical is processed in block 8 by amplification and detection, and then reproduced as a spectrum of amplitudes of a spatially periodic signal that is functionally dependent on the spatial frequency of the signal. Information about the dispersed system is obtained by analyzing the nature of the change in the amplitude spectrum of a spatially periodic signal as a function of the spatial frequency, in particular, on the ratio of the amplitudes of the zero and fixed frequency signals, or by analyzing the nature of the change in the spatial intensity distribution in the receiving element plane of unit 7 based on the dependence 35 40 45 50 ΐ (χ ^! ) coH (-)) cos} x ⁽ , where is x ^! - coordinate in the plane of the receiving element; cos ^ x ¹ - a function characterizing the form of a spatially periodic signal in the plane of the receiving element; H (-O) is a function characterizing the amplitude of a spatially periodic signal, i.e. representing the spectrum of the amplitudes of the signal cosox ¹ in the plane of the receiving element, depending on the spatial frequency. This function is a spatial spectrum of the scattering indicatrix of the dispersed system under study. For monodisperse system function H (3) is equal to BUT) = exp * 55 160G512 G. 1 X and - ~ (agssosis ~ _a - ~ (one) where άν is the volume concentration of particles in a dispersed system, parts / μm *; a is the radius of the particle; YU Ζ - thickness of the dispersed system; 'D - radiation wavelength. From the expression (1) it follows that 15 ItN (9) = βχρί-ΐΓάνβ ² ) (2) "about ΙΐιηΗ (ί) = exp (-2kKga Ζ), (3) where expression (2) characterizes the value of the function H0) at zero spatial frequency. Expression (3) characterizes the value of the function H (H) at a fixed spatial frequency } = - ^ · First, determine the radius a from the graph of the recorded function H (^) based on the expression (3), from which \ 2a it follows that at H = - function And O) does not change, i.e. is constant and goes to straight line \ 73 plot at the moment when H = - * · D Consequently, according to the graph of the recorded function H0), the frequency Ό is determined at which C (}) becomes constant, i.e. parallel to the x-axis, then but (H Then, the concentration of particles is determined by dividing expression (2) by expression (3) followed by substituting the values of Ζ into the resulting expression and the values of the radius a άν = 1n ( H (0) Since the values of Ζ and 'D