SU1392538A1 - Laser resolution meter - Google Patents

Abstract

The invention relates to photosensitive materials testing means and allows for improved accuracy and performance testing. The collimated source of I radiation forms a flat coherent wave, illuminating the diffraction element 2, made in the form of a set of diffraction grids arranged one under another with varying no more than pa octaves. n |) () Strang () 11 frequency). The cylindrical component lg 3 and the spherical KOMIIOHOIII 4 exchanged behind it form the diaphragm planes and the inverted image of the le Meerara 2. Next through the styling of the diaphragm 5, the light points form the image v in the plane of the material used 7. ieMenTa 2. The second cylindrical component 6 implements the optical conjugation of the aperture of a diaphragm 5 with n. iocKocTiiK) of the test material 7, in which | K) th there are sharply outlined images of the areas of diffraction gratings: 1, 1, 2, zano. 1n1) 1e sinusoidal distribution of non-temporal spatial fraction () 1y. Manage 1 contrasting the distribution of lightness in the plane of the test material 7 is measured by means of a set of replacement filters 8. For new developments from the non-effective efficiency of element 2, it is derived from a set of phase diffraction peHicTOK with (H1mme1- Rich11 M nrO) (> and 1. I Cp f-.ch. 3 and. 1. (O (/ s

Description

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The invention relates to means for testing photosensitive materials, namely, devices for recording renolograms in measuring spatial-frequency characteristics and dispersion of materials.

The purpose of the invention is to improve the accuracy and performance of resolvative tests by simultaneously exposing all the fields of the resolvent.

} fa of fig. 1 shows a diagram of a laser resolver; in fig. L and 3 ray paths in the meridional and cai lines of the optical sections of the optical vema of the resolvometer, respectively.

Laser resolvometer contains count. the coherent radiation source 1 1, the diffraction element 2, which is a set of several remote sensors under a different diffraction grating with a variable frequency of strokes, the first positive cylindrical component 3, whose front focal plane coBMenie) ia with n: 1 - ({) is functional | () of element 2, positive with () component 4, paired np, 1otnun) to the cylindrical component 3, diaphragm, D), containing several pairs of sym) (ico) asheld from versts and, Th) without the passage of light pass Otok, cooi corresponds to the first and .minus to the first by 1 diffraction chambers on the gratings, the input is inn.x in the diffraction element 2, the second along the curve is the gel cylindrical component C), which is osus. 1 is an angular contact of the plane of the diaphragm 5 with the correctness of the test material 7, a set of interchangeable | 1gP)) into 8,} by which you can change the cohp (ipippelsivnosti diffra-1-irovap1n, 1x beams of the first and second order - K (n and yn |) avt) by the contrast of the distribution of illumination in the plane of the ejected mageal.

With such an execution, the resolvent (.) Meter image of the element in the plane of isytu- IOC) matter, 1a forms) there is two similarity - P1imis coherent beams corresponding to the first and minus the first diffraction order, which leads to the appearance of a sinusoidal distribution light frequency variable in the range of vol. The image edges of each grid are due to ipters rentia. Measuring the frequency by no more than an octave, in each of the gratings, allows for a small amount to filter out the highest order diffraction. which provides high contrast and precision in sinusoidal light distribution. The fs circuit regulates several variable points at the same time. what allows ex-ioning the resolvogram in the range n) of the frequencies from VH-U to 2 N; IVMKH; minimum frequency; N counts

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individual diffraction gratings in the diffraction unit).

Since the sinusoidal distribution of illumination in the plane of the test material is provided for any distribution profile of the complex amplitude transmittance of the diffraction grating of the first grating, phase diffraction gratings with a rectangular or symmetrical triangular profile should be used to increase the light coefficient of the resolvometer.

When using diffraction gratings with a symmetrical groove profile, the contrast of the distribution of illumination in the output plane of the resolver almost reaches 100%. In order to control the magnitude of the contrast, interchangeable light filters were added to the design of the resolvometer, overlapping half of the diaframe1M1 1 (corresponding to either the first or the minus first diffraction on the diffractive element).

Laser reschvomet works as follows.

The co-luminated radiation source 1 forms a flat coherent wave illuminating the diffractive element 2. The system, consisting of a cylindrical coupling 3 and a spherical component 4, in the meridional section forms an inverted image of the diffraction element 2 in the plane of the diaphragm 5. In the sagittal section (Fig. 3) in the filter plane 5 f) A one-dimensional Fourier spectrometer of diffractive element 2 is formed, consisting of a set of diffraction orders on the slats that make up the diffractive element 2. The diffraction orders are not ryvayuts, since a change in the spatial frequency of grooves along each of the arrays is less than an octave. Only the first and minus first diffraction orders pass through the holes in the diaphragm 5. The transmitted light beams form in the sagittal 1 st section an image of the diffraction element 2 in the plane of the test material 7, and the interference of the first and minus first order beams results in a sinusoidal illumination distribution with a slowly varying spatial frequency. The contrast of the sinusoidal illumination distribution is determined by the ratio of the intensity of the interfering beams; therefore, by introducing a attenuating filter 8 in one of the diffraction orders, it is possible to contrast the illumination distribution in the plane 7.

In the meridional section (Fig. 2), the cylindrical component b also forms an image of diffractive element 2 in plane 7. Therefore, sharply outlined images of diffraction gratings of diffractive element 2, filled with a sinusoidal illumination of variable spatial frequency, are observed in the plane of the test material.

The linear magnification coefficients of the optical scheme of the resolvometer in the meridional and sagittal sections are generally not the same, which does not prevent its normal functioning.

Thus, with the proposed arrangement of the optical elements of a resolvometer and using phase diffraction gratings of a special type, all the resolvogram fields corresponding to different spatial frequencies are exposed simultaneously, which leads to an increase in the accuracy and performance of resolvometric tests.

The invention also provides a simplification of the resolvometer design by eliminating the elements (mirrors, multipliers, etc.) that are moved (in the process of exposing one resolvogram).

The sinusoidal illumination distribution in the output plane simplifies the procedure for determining the spatial-frequency characteristics of photosensitive materials, which implies the presence of complex recalculations of measured values with non-sinusoidal distributions of the superimposed exposure.

The optical scheme of the resolver when replacing element 2 with a multichannel spatial light modulator can also be used for spatial filtering of multichannel signals.

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Claims (2)

1. Laser resolver, including a source of collimated coherent radiation arranged in series on the optical axis, a diffractive element, a positive spherical component placed in the back of a focal point: 11111 plane of the positive spherical component aperture in the form of a set of holes that allow the first and minus perforations of the diffraction to the diffraction :) a lecture, characterized in that, in order to improve the accuracy and performance of resolvometric tests, two positive are introduced x cylindrical components, the first of which is located in front of the positive spherical component, while its front focal plane is aligned with the plane of the diffractive element, the second cylindrical component is located behind the diaphragm, and the diaphragm plane and the plane for mixing the material under test are conjugated, and the diffraction plane The element is made in the form of a set of diffraction gratings with varying not more than an octave spatial frequency, placed one below the other in the plane, perpe Dikulja molecular optical axis, wherein the cylindrical components forming mutually parallel and perpendicular strokes. 2. Resolvometer according to claim 1, characterized in that, in order to increase the light efficiency, the diffraction element is designed as a set of phases, 1x diffraction gratings with a symmetric profile. .2 ue.J