RU2252440C1 - Objective for night vision devices - Google Patents

Abstract

FIELD: optical engineering.

SUBSTANCE: objective has six optical components. The first component is made in form of single positive biconvex lens, the second component is made in form of positive concave-convex lens glued with negative convex-concave lens; convex part of positive lens is turned to the first component. The third component is made in form of single negative menisc which has its concave surface turned to the second component. The fourth component is made of biconvex and biconcave lenses glued together to have convex part of the assembly turned to the third component. The fifth component is made in form of single biconcave lens. The sixth component has to be single negative menisc having its concave part turned to the fifth component. Aberrations are reduced including aberrations at the edge of field of view. Polychromatic frequency-contrast response are provided to be high taking spectral efficiency of photocathode into account at higher spatial frequency range.

EFFECT: improved operational characteristics.

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Description

The invention relates to the field of instrumentation, in particular to optical instrumentation, and can be used in the development and modernization of night vision devices.

Known six-lens lens for night vision devices “Helios PA” / 1 / with an entrance pupil diameter of 100 mm and a relative aperture of 1: 1.5, containing four optical components, the first of which from the side of the space of objects the component is made in the form of a single biconvex lens, the second the component is made in the form of a gluing consisting of 10 two convex-concave lenses, a convex surface facing the first component, the third component is a gluing consisting of a biconcave and biconvex lens, concave rhnostyu facing to the second component, the fourth component is a single biconvex lens.

The disadvantage of the lens are insufficiently corrected levels of aberrations, insufficient level of frequency-contrast characteristics.

Known eight-lens, containing six optical components, the first of which is made in the form of a single positive convex-concave lens, convex surface facing the space of objects, the second component is made in the form of a single positive convex-concave lens, convex surface facing the first component, the third component made in the form of gluing, consisting of a biconvex and biconcave lenses, a convex surface facing the second component, the fourth component is made in the form single negative meniscus concave surface facing the third component, the fifth component is in the form of gluing, consisting of a biconcave and a biconvex lens, a convex surface facing the fourth component, the sixth component - a single biconvex lens / 2 /.

The diameter of the entrance pupil of the lens is 104 mm, the relative aperture is 1: 1.65.

Figure 1 presents a schematic optical diagram of the lens, where the numbers indicate the numbers of the components of the lens.

Table I shows the values of the radii of the lenses, the thickness of the lenses, air gaps, glass brands of the specified lens.

Table I №№ p.p. Radii of curvature, mm Axial distances, mm Glass brands 0 - - air 1 159,706 17,000 TK121 2 682,325 3,000 air 3 274,223 13,000 TK121 4 471,807 3,000 air 5 132,465 22,000 TK121 6 -498,846 6,000 TF107 7 116,122 22,100 air 8 -108,652 7,000 TF110 nine -216,280 9,000 air 10 103,030 18,000 TK121 eleven -103,030 8,000 OF101 12 59,018 7,330 air thirteen 132,465 11,830 TK121 14 -191340 85,208 air fifteen 0,0 7.9 K8 16 00 air

The lens forms an image of the subject with polychromatic contrast taking into account the spectral efficiency of the multi-alkaline photocathode in accordance with the data in Table II, which shows the frequency-contrast characteristics for a number of spatial frequencies in the plane of the best setup taking into account the spectral efficiency of the multi-alkaline photocathode. A graph of the spectral efficiency of a multi-alkaline photocathode is shown in FIG.

Table II System-Lens o / j = 1.66 / 172 2w = 6 ° Frequency contrast response Space frequency, lin / mm Point on axis Y = -3,000 Y = -2.3555 Y = -2.0719 Y = -1,3004 measures. sag. measures. sag. measures. sag. measures. sag. Polychromatic _(n continuous spectrum λ = 546nm, λ = 900nm _in) 0.00 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 10.00 0.95 0.47 0.86 0.53 0.90 0.65 0.92 0.81 0.94 20.00 0.82 035 0.58 0.39 0.67 0.45 0.75 0.57 0.80 30.00 0.71 0.27 0.35 0.32 0.47 0.38 0.59 0.47 0.67 40.00 0.63 0.23 0.20 0.27 0.32 0.33 0.46 0.41 0.58 50.00 0.58 0.20 0.12 0.24 0.21 0.29 0.36 0.37 0.51 60.00 0.53 0.17 0.10 0.21 0.14 0.25 0.27 0.34 0.44 70.00 0.49 0.15 0.10 0.18 0.11 0.23 0.20 0.31 0.37 80.00 0.45 0.13 0.10 0.16 0.11 0.21 0.16 0.29 0.32 90.00 0.42 0.12 0.08 0.15 0.10 0.19 0.14 0.26 0.28 100.00 0.38 0.10 0,07 0.13 0.09 0.18 0.13 0.25 0.24 o / j - relative aperture / focal length,
w - half the angle of the field of view of the lens,
Y is the angular coordinate.

The disadvantage of the lens is the insufficiently corrected levels of aberrations, the insufficiently high level of frequency-contrast characteristics, mainly along the edge of the field of view. With the currently available electron-optical converters with direct image transfer and uniform resolution over the entire field of view, this is a significant drawback.

The objective of the invention is to create a lens mainly with an entrance pupil diameter of 102 mm and a relative aperture of 1: 1.65 with satisfactorily corrected aberration levels, including along the edge of the field of view, having high values of polychromatic frequency-contrast characteristics taking into account the spectral efficiency of the multi-alkaline photocathode in the region increased spatial frequencies and, as a result, providing a high, competitive range of vision for observation devices created on the basis of lens and image intensifiers.

This object is achieved by the fact that a lens is proposed that contains six optical components, the first of which from the side of the space of objects is made in the form of a single biconvex lens, the second component is made in the form of gluing from two lenses, the first of which is a positive convex-concave lens, the second negative convex-concave lens, the convex surface of the positive lens facing the first component, the third component is made in the form of a single negative meniscus, the concave surface of the inverted to the second component, the fourth component is made in the form of gluing from two lenses, the first of which is a biconvex lens, the second is a biconvex lens, the biconvex lens facing the third component, the fifth component is made in the form of a biconvex lens, the sixth component is made in the form of a single negative meniscus, concave surface facing the fifth component.

The difference of the proposed lens is that the first component is made in the form of a biconvex lens, the second component is made in the form of gluing from two lenses, the first of which is a positive convex-concave lens, the second is a negative convex-concave lens, the convex surface of the positive gluing lens facing the first component, the third component is made in the form of a single negative meniscus, with a concave surface facing the second component, the fourth component is made in the form of gluing from biconvex and two ovaconvex lens, a biconvex lens facing the third component, the fifth component is made in the form of a single biconvex lens, the sixth component is made in the form of a single negative meniscus, a concave surface facing the fifth component. The invention is illustrated in the drawing. Figure 3 presents a schematic optical diagram of the proposed lens. The lens has an entrance pupil diameter of 102 mm, a relative aperture of 1: 1.65 and a focal length of 167.81 mm. Table III shows the values of the radii of the lenses, the thickness of the lenses, air gaps and glass brands of the inventive lens.

Table III №№ p.p. Radii of curvature, mm Axial distance mm Glass brands 0 - - air 1 276,100 14,400 TK21 2 -318,724 8,600 air 3 86,500 15,500 TK21 4 2713,552 5,000 TF5 5 107,400 17,000 air 6 -153,460 6,000 TF5 7 -1025,709 27,850 air 8 261,200 17,000 BK10 nine -56,490 6,900 OF6 10 56,490 2,670 air eleven 59,980 18,000 TK21 12 -125,030 56,240 air thirteen -39,720 4,000 QOL 14 -88,720 14,793 air fifteen 0,000 3,200 K8 16 0,000 - air

Table IV shows the values of the polychromatic frequency-contrast characteristics of the proposed lens.

Table IV Lens system o / j = 1.65 / 168 2w = 6 ° 14 ’ Frequency contrast response Space frequency, lin / mm Point on axis Y = -3.07 Y = -2.4159 Y = -2.1216 Y = -1.3334 measures. sag. measures. sag. measures. sag. measures. sag. Polychromatic _(n continuous spectrum λ = 546nm, λ _B = 900 nm) 0.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 10.00 0.99 0.96 0.96 0.97 0.97 0.98 0.98 0.98 0.98 20.00 0.94 0.86 0.85 0.89 0.89 0.91 0.91 0.93 0.93 30.00 0.88 0.73 0.74 0.78 0.79 0.83 0.83 0.86 0.87 40.00 0.81 0.61 0.64 0.67 0.69 0.74 0.75 0.79 0.79 50.00 0.74 0.51 0.57 0.57 0.62 0.65 0.68 0.71 0.72 60.00 0.68 0.42 0.52 0.49 0.56 0.58 0.62 0.64 0.66 70.00 0.61 0.34 0.48 0.41 0.51 0.51 0.57 0.58 0.60 80.00 0.55 0.28 0.44 0.35 0.48 0.46 0.53 0.53 0.56 90.00 0.50 0.23 0.40 0.30 0.44 0.41 0.49 0.48 0.51 100 0.45 0.19 0.37 0.26 0.41 0.37 0.46 0.44 0.48 o / j is the relative aperture / focal length;
w - half the angle of the field of view of the inventive lens;
Y is the angular coordinate.

The lens forms an image of an object with polychromatic frequency-contrast characteristics taking into account the spectral efficiency of a multi-alkaline photocathode (Fig. 2) in accordance with the data in Table IV. As can be seen from the tables of values of polychromatic frequency-contrast characteristics (table. II) of the prototype lens and table. IV - of the proposed lens, calculated in the same spectral range of wavelengths of 546.1 ... 900 nm and taking into account the same values of the spectral efficiency of the multi-alkaline photocathode, the proposed lens provides a significantly higher contrast for the formation of the image of the observation objects as for a point on the axis, so for the angular field of view. This will provide a significant increase in the range of vision of night vision devices. In tables I and III, line 15 in the column “axial distances” shows the thicknesses of the photocathode glasses of the image intensifiers along with the thicknesses of the compensation plates (selected structurally), together with which the lenses work. The use of the proposed lens will provide a high range of vision and, accordingly, the competitiveness of night vision devices.

Sources of information used;

1. The lens "Helios-PA". Specifications BLZ.877.044 TU, 1973

2. Eurasian patent No. 000569, Eurasian application No. 199800359 of 04/21/98 (prototype).

Claims (1)

A lens for night vision devices containing six optical components, characterized in that, in order to increase the contrast of the image, the first component from the side of the space of objects is made in the form of a single biconvex lens, the second component is made in the form of gluing from two lenses, the first of which is positive convex-concave lens, the second negative convex-concave lens, the convex surface of the positive gluing lens facing the first component, the third component is made in the form of a single negative of the body meniscus, with a concave surface facing the second component, the fourth component is made in the form of gluing from two lenses, the first of which is a biconvex lens, the second is a biconcave lens, the convex surface of the first gluing lens facing the third component, the fifth component is made in the form of a biconvex lens , the sixth component is made in the form of a single negative meniscus, with a concave surface facing the fifth component.

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