RU208915U1 - WIDE-ANGLE RADIATION-RESISTANT LENS - Google Patents

Abstract

The utility model relates to optical instrumentation, and more specifically to wide-angle lenses used in various optical devices and components that require a large back focal length, high image quality in a wide spectral range and the presence of a variable aperture diaphragm, including in complexes operating under conditions radiation. The technical result of the proposed utility model is to increase the field of view of the lens and improve the quality of the resulting image. A wide-angle radiation-resistant lens consists of five components 1-5 in series along the beam and an active aperture diaphragm located between components 3 and 4. Component 1 is made in the form of three single negative menisci 6-8, located with a concave side to the image space, component 2 and 3 - positive menisci, located with a concave side to the space of objects, glued from biconcave 9 and 11 and biconvex lenses 10 and 12, component 4 - two single positive menisci, of which the meniscus 13 faces the concave side to the image space, and the meniscus 14 faces the concave side to the space of objects, component 5 is a biconvex lens glued from a biconvex lens 15 and a negative meniscus 16, the distance between the third component and the diaphragm is (0.5 ... 0.6) ƒ'rev, the distance between the fourth component and the diaphragm is (0 .25 ... 0.35)ƒ'rev, which ensures the installation of an active variable iris diaphragm, o the optical powers of the components are (-1.0…-1.1)ϕ'rev, (3.1…3.2)ϕ'rev, (27…30)ϕ'rev, (2.9…3.1) ϕ'obi (6.0…6.2)ϕ'respectively, where ƒ'is the focal length of the lens, ϕ'is the optical power of the lens. 2 ill., 3 tab.

Description

The proposed utility model relates to optical instrumentation, and more specifically to wide-angle lenses used in various optical devices and components that require a wide field of view, high image quality in a wide spectral range and the presence of a variable aperture diaphragm, including in complexes operating under conditions radiation.

A wide-angle lens is known (RF patent No. 2445658, dated December 30, 2010, publ. March 20, 2012, IPC G02B 9/62), consisting of a plano-convex lens facing the object with its plane, a plano-concave lens facing the object with its plane, a single biconvex lens, biconcave a lens glued to a biconvex lens, a single biconvex lens, a single negative meniscus with its concavity facing the image. The following ratios take place in the lens: 1.63<n ₁ =n ₂ <1.68; 1.73 _<5 n <2.1; 1.57 <n ₆ <1.64;1.6<n ₈ <1.675, where n ₁ , n ₂ , n ₅ , n ₆ , n ₈ are the refractive indices of the material, respectively, of the first and second lenses of the first component, the biconcave and biconvex lenses of the third component and the meniscus of the fourth component for the line d. An aperture diaphragm is located in front of the biconcave lens. A plane-parallel plastic or light filter may be placed in front of a biconcave lens.

The disadvantages of the given lens are a small rear segment of the order of fractions of a millimeter, a small relative aperture (1:3.5), an insufficiently wide field of view (70 °), and the impossibility of the lens to work under radiation conditions.

A wide-angle lens with a large relative aperture is known (RF patent No. 2351968, dated July 30, 2007, published on April 10, 2009, IPC G02B 9/64), containing seven optical components and an aperture diaphragm located between the fifth and sixth components. The first component is positive, the second is negative, made in the form of a meniscus, concavity facing the image. The third is negative, and the fourth is negative and is glued together from biconcave and biconvex lenses. The fifth is made in the form of a biconvex lens. The sixth is made in the form of a single biconcave lens. The seventh one is in the form of a positive meniscus with its concavity facing the object. After the seventh component, the eighth component is additionally introduced, made in the form of a biconvex lens, the ninth component is positive and glued from the negative meniscus, the concavity facing the image, and the positive lens, the tenth component, made in the form of the negative meniscus, the convex side facing the image, and the eleventh component , made positive and glued from biconvex and biconcave lenses.

The disadvantages of this lens are the impossibility of the lens operation in radiation conditions, low image quality, and the impossibility of working with 2/3'' receivers.

The closest in technical essence is a wide-angle television lens (USSR patent No. 1788493, dated February 27, 1991, published on January 15, 1993, IPC G02B 9/64), made of radiation-resistant glass, which was adopted by the authors as a prototype.

The lens contains a protective glass, two positive menisci installed in front of the first component, the second component is made in the form of a biconcave lens, the third, fourth and fifth components are made in the form of positive lenses, the sixth and seventh components are made in the form of double-glued lenses, and the receiving area of the electron beam tubes. The lens field of view angle is 70°, the maximum relative aperture is 1:2, the lens is achromatized in the wavelength range of 547-750 nm. The image contrast at a frequency of 30 lines/mm on the axis and at the edge of the field of view is 0.7 and 0.1, respectively.

The disadvantage of the known prototype lens is not wide enough field of view, not wide enough working spectral range and low image quality.

The problem solved by the claimed utility model is the creation of a wide-angle radiation-resistant lens with improved image quality characteristics.

The technical result of the proposed utility model is to increase the field of view of the lens, expand the working spectral range and improve the quality of the resulting image.

This is achieved by the fact that the lens, consisting of five components arranged in series along the radiation path and an active aperture diaphragm, is characterized in that the first component is made in the form of three single negative menisci, located with the concave side to the image space, the second and third are positive menisci located the concave side to the space of objects, glued from a biconcave and biconvex lenses, the fourth - two single positive menisci, the first of which faces the concave side to the space of objects, the second - to the space of images, the fifth - a biconvex lens glued from a biconvex lens and a negative meniscus, between the third and fourth components are the active aperture diaphragm, the distance between the third component and the diaphragm is (0.5 ... 0.6) ƒ' _about , the distance between the fourth component and the diaphragm is (0.25 ... 0.35) ƒ' _about , which provides installation of the operating variable iris diaphragm hma, the optical powers of the components are (-1.0…-1.1)ϕ' _about , (3.1…3.2)ϕ' _about , (27…30)ϕ' _about , (2.9…3, 1) φ 'and _an (6,0 ... 6,2) φ' _of, respectively, where ƒ _'of - lens focal distance, φ' _of - optical power of the lens.

Reducing the focal length of the lens compared to the prototype while maintaining the size of the image can significantly increase the field of view up to 91°. The first component, made of three negative menisci, provides high correction of astigmatism and visual field curvature. The implementation of the third component glued from biconcave and biconvex lenses allows you to correct the magnification chromatism. The implementation of the fourth component in the form of two separate lenses provides for the correction of position chromatism. The fifth component, made positive in strength and glued from two lenses, the first of which is positive biconvex, the second is negative biconcave, corrects distortion, and residual position and magnification chromatism.

The essence of the invention is illustrated by drawings. In FIG. 1 shows the optical scheme of a wide-angle radiation-resistant lens. In FIG. 2 shows the polychromatic frequency-contrast characteristic of the lens for a relative aperture of 1:2.8 and an angular field of 2ω=91°.

The wide-angle radiation-resistant lens contains five components 1-5 arranged in series along the beam and an active aperture diaphragm located between components 3 and 4. Component 1 is made in the form of three single negative menisci 6-8, located with a concave side to the image space, component 2 and 3 - positive menisci, located with a concave side to the space of objects, glued from biconcave 9 and 11 and biconvex lenses 10 and 12, component 4 - two single positive menisci, of which the meniscus 13 is facing the concave side to the image space, and the meniscus 14 is facing the concave side to the space of objects, component 5 is a biconvex lens glued from a biconvex lens 15 and a negative meniscus 16, the distance between the third component and the diaphragm is (0.5 ... 0.6)ƒ' _rev , the distance between the fourth component and the diaphragm is (0 .25…0.35)ƒ' _rev , which ensures the installation of an active variable iris diaphragm s, the optical powers of the components are (-1.0…-1.1)ϕ' _about , (3.1…3.2)ϕ' _about , (27…30)ϕ' _about , (2.9…3, 1) φ 'and _an (6,0 ... 6,2) φ' _of, respectively, where ƒ _'of - lens focal distance, φ' _of - optical power of the lens. All components are made of 200 series optical glass, which provides a high radiation resistance of the lens.

An example of a specific implementation of the proposed utility model is a wide-angle radiation-resistant lens having a focal length ƒ'=6.15 mm, a relative aperture D/ƒ'=1:2.8 and an angular field 2ω=91°, the technical characteristics of which are presented in Table 1 The lens has an extended working spectral range from 0.485 to 0.760 microns, unlike the prototype, which is achromatized from 0.545 to 0.75 microns. All optical elements are made of radiation-resistant glass, which is confirmed by the design parameters presented in table 2. The improvement in image quality compared to the prototype is confirmed by table 3, which shows the polychromatic diffractive frequency-contrast response of the lens. At a frequency of 30 lines/mm, the lens image contrast in the center and at the edge of the field of view is 0.79 and 0.72, respectively, while in the prototype at a frequency of 30 lines/mm, the contrast in the center of the field of view is 0.7, and at the edge field of view 0.1. The optimal resolution of the lens is provided at a frequency of 80 lines / mm with a contrast in the center of the field of view above 0.45, and at the edge of the field of view above 0.35.

The technical advantage of the proposed utility model, in comparison with the prototype, is:

21° increased field of view;

extended working spectral range from 0.475 µm to 0.76 µm;

improved image quality across the entire field of view.

The implementation of the technical advantages of the lens according to the proposed utility model increases its resolution, high information content, which allows it to be used in various fields of instrumentation, including in complexes operating under gamma radiation conditions.

Claims (1)

A wide-angle radiation-resistant lens consisting of five components arranged in series along the radiation path and an active aperture diaphragm, characterized in that the first component is made in the form of three single negative menisci, located with the concave side to the image space, the second and third are positive menisci, located with the concave side to the space of objects, glued from a biconcave and biconvex lenses, the fourth - two single positive menisci, the first of which faces the concave side to the space of objects, the second - to the space of images, the fifth - a biconvex lens glued from a biconvex lens and a negative meniscus, between the third and the fourth component is the active aperture diaphragm, the distance between the third component and the diaphragm is (0.5…0.6)ƒ' _rev , the distance between the fourth component and the diaphragm is (0.25…0.35)ƒ' _rev , which ensures the installation current variable iri oval diaphragm, the optical powers of the components are (-1.0…-1.1)ϕ' _rev , (3.1…3.2)ϕ' _rev , (27…30)ϕ' _rev , (2.9…3 1) φ 'and _an (6,0 ... 6,2) φ' _of, respectively, where ƒ _'of - lens focal distance, φ' _of - optical power of the lens, wherein all the lens components are made of radiation resistant glass 200 series .

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