RU2368923C2 - Lens for night viewers - Google Patents

Abstract

FIELD: instrument making.

SUBSTANCE: lens comprises six optical components, the first of which from the side of object space is arranged in the form of single convexo-convex lens. The second component is made in the form of patch of two lenses, the first of which - convexo-convex lens, the second - concavo-concave lens, with convexo-convex lens inverted to the first component. The third component - single concavo-concave lens. The fourth component is made in the form of patch from convexo-convex and concavo-concave lenses, besides convex surface of patch is inverted to the third component. The fifth component is made in the form of single convexo-convex lens, the sixth component - single negative meniscus, which is inverted with its concave surface to the fifth component.

EFFECT: provides for reduction of aberrations, also along edge of visual field, and also obtainment of high values of polychromatic frequency-contrast characteristics in the field of higher spatial frequencies with account of spectral characteristics of photocathode.

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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 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 component is made in the form of a gluing consisting of 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 along erhnostyu facing to the second component, the fourth component is a single biconvex lens.

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

Known eight-lens (application No. 2004108179/28 (08911) in FIPS) containing six optical components, the first of which is made in the form of a single biconvex lens, the second component is made in the form of gluing from a positive convex-concave and negative convex-concave lenses, convex the 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 facing the second component, the fourth component is made in the form of gluing in two convex and biconcave lenses, while the convex gluing surface faces the third component, the fifth component is made in the form of a single biconvex lens, the sixth component is a single negative meniscus, with a concave surface facing the fifth component [2] (Fig. 1). The diameter of the entrance pupil of the lens is 102 mm, the relative aperture is 1: 1.65. Table I shows the design parameters of the specified lens.

Table I No. p.p. Radii of curvature, mm Axial distance mm Glass brands 0 - - air one 276,100 14,400 TK121 2 -318,724 8,600 air 3 86,500 15,500 TK121 four 2713,552 5,000 TF105 5 107,400 17,000 air 6 -153,460 6,000 TF105 7 -1025,709 27,850 air 8 261,200 17,000 BK110 9 -56,490 6,900 OF6 10 56,490 2,670 air eleven 59,980 18,000 TK121 12 -125,030 56,240 air 13 -39,720 4,000 K108 fourteen -88,720 13,241 air fifteen 0,000 5,600 K108 16 0,000 air

The lens forms an image of the object with polychromatic contrast, taking into account the spectral efficiency of the arsenide-galium photocathode (third-generation electron-optical converter) in accordance with the data in Table II, which shows the values of the frequency-contrast characteristics for a number of spatial frequencies in the plane of the best setting, taking into account the spectral characteristics of the arsenide-galium photocathode. A graph of the spectral characteristics of the arsenidegalium photocathode is shown in Fig.2.

The lens was designed to work with a specific Russian electron-optical converter with a multi-alkaline photocathode, including a two plus generation electron-optical converter with a photocathode glass thickness of up to 3.2 mm. The lens provides high contrast image.

However, the disadvantage of the lens should be attributed to the fact that when working with modern and promising electron-optical converters with a glass thickness of the photocathode, usually equal to 5.6 mm, and a resolution limit of about 100 pairs of strokes per millimeter, its contrast along the edge of the field of view at limiting spatial frequencies may not be enough to confidently identify the observed object at extremely long ranges.

Table II System-Lens o / j = 1.6 / 168 2w = 6 ° 14 ' Frequency contrast response Space frequency, Point on axis Y = -3.0700 Y = -2.4159 Y = -2.1216 Y = -1.3334 lin / mm measures. ca. measures. ca. measures. ca. measures. ca. Polychromatic _(n continuous spectrum λ = 546 nm, λ = 900 nm _in) 0.00 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 10.00 1,0 0.98 0.99 1,0 1,0 1,0 1,0 1,0 1,0 20.00 0.96 0.85 0.87 0.89 0.91 0.93 0.94 0.95 0.95 30.00 0.88 0.69 0.73 0.76 0.79 0.82 0.84 0.86 0.87 40.00 0.78 0.55 0.61 0.63 0.68 0.71 0.74 0.76 0.77 50.00 0.68 0.44 0.52 0.52 0.58 0.61 0.64 0.66 0.67 60.00 0.57 0.36 0.45 0.44 0.50 0.52 0.55 0.57 0.58 70.00 0.47 0.30 0.39 0.37 0.43 0.44 0.47 0.48 0.49 80.00 0.39 0.25 0.33 0.32 0.37 0.38 0.40 0.41 0.41 90.00 0.31 0.22 0.29 0.27 0.32 0.32 0.34 0.34 0.34 100.00 0.25 0.18 0.25 0.23 0.27 0.27 0.30 0.29 0.29 o / j is the relative aperture / focal length;
w is half the angle of the field of view of the lens;
Y is the angular coordinate.

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 arsenide galium photocathode in the region increased spatial frequencies and, as a result, providing a high, competitive range of vision for observational instruments created on the basis of the decree This lens and third-generation 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 biconvex lens, the second is a biconcave lens, biconvex lens facing the first component, the third component is made in the form of a single biconcave lens, the fourth component is made in the form of gluing two lenses, the first of which is biconvex lens, a second - a biconcave lens, a biconvex lens facing the third component, the fifth component is a biconvex lens, a sixth component configured as a single negative meniscus concave surface facing to the fifth component. The difference of the proposed lens is that the first from the side of the space of objects lens of the second component glued from two lenses is made in the form of a biconvex lens. the second lens of the second component is made in the form of a biconcave lens, and the third component from the side of the space of objects is a biconcave lens. The invention is illustrated in the drawing. Figure 3 presents a schematic optical diagram of the inventive lens. The lens has an entrance pupil diameter of 102 mm, a relative aperture of 1: 1.65 and a focal length of 167.909 mm. Table III shows the values of the design parameters of the inventive lens. Table IV shows the values of the polychromatic frequency-contrast characteristics of the inventive lens for a number of spatial frequencies in the plane of the best setting, taking into account the spectral characteristics of the arsenide galium photocathode

Table III No. p.p. Radii of curvature, mm Axial distance mm Glass brands 0 - - air one 163,680 16,400 TK21 2 -746,400 12,000 air 3 104,230 15,700 TK21 four -809,100 6,000 TF5 5 132,130 12,700 air 6 -223,900 7,000 TF5 7 623,700 22,900 air 8 194.54 17,300 BK10 9 -55,340 8,000 OF6 10 55,340 3,100 air eleven 57,810 18,000 TK21 12 -151,690 56,240 air 13 -37,840 4,000 K8 fourteen -80,100 10,208 air fifteen 0.000 7,600 K8 16 0.000 air

Table IV System-Lens o / j = 1.65 / 168 2w = 6 ° 14 ' Frequency contrast response Space frequency, lin / mm Point Y = -3.07 Y = -2.4159 Y = -2.1216 Y = -1.3334 on axis measures. ca. measures. ca. measures. ca. measures. ca. Polychromatic _(n continuous spectrum λ = 546 nm, λ = 900 nm _in) 0.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 10.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 20.00 0.93 0.88 0.91 0.89 0.92 0.91 0.93 0.93 0.93 30.00 0.84 0.74 0.80 0.77 0.81 0.80 0.83 0.83 0.84 40.00 0.75 0.62 0.70 0.65 0.71 0.70 0.73 0.73 0.74 50.00 0.67 0.52 0.61 0.56 0.62 0.61 0.64 0.65 0.66 60.00 0.60 0.45 0.54 0.49 0.55 0.54 0.57 0.58 0.59 70.00 0.55 0.40 0.49 0.44 0.50 0.48 0.52 0.52 0.54 80.00 0.50 0.37 0.45 0.40 0.45 0.44 0.48 0.48 0.49 90.00 0.47 0.34 0.41 0.37 0.42 0.41 0.44 0.44 0.46 100.00 0.44 0.31 0.38 0.34 0.39 0.38 0.41 0.41 0.43 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 the arsenide-gallium photocathode (figure 2) in accordance with the data in table IV. As can be seen from the tables of values of the polychromatic frequency-contrast characteristics (Table II) of the lens - the prototype and Table IV - of the inventive 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 arsenide the photocathode, the proposed lens provides a significantly higher contrast imaging of the objects of observation for both the point on the axis and the angular field of view in the region of increased spatial frequencies. This will provide an increase in the range of vision of night vision devices. In tables I and III, line 15 in the column “axial distances” indicates the thickness of the photocathode glass of the image intensifier ”, including in table. III together with the thickness of the compensation plate (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, will ensure maximum use of the capabilities of modern and promising electron-optical converters.

Information Sources Used

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

2. Application No. 2004108179/28 (008911) for the grant of a patent of the Russian Federation for the invention of “Lens for night vision devices” is a prototype.

Claims (1)

A lens for night vision devices, containing 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 third component is made in the form of a single lens, the fourth component is made in the form of gluing 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 In this case, the sixth component is made in the form of a single negative meniscus, with a concave surface facing the fifth component, characterized in that the first component-side lens of the second component facing the first component is made in the form of a biconvex lens, and the second lens of the second component is made in the form biconcave lens, the third component is made in the form of a biconcave lens.

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