RU2726261C1 - High-output lens - Google Patents

Abstract

FIELD: optics.SUBSTANCE: lens can be used in optical systems operating in both visible and infrared spectral ranges, particularly in television cameras operating with a receiving matrix. fast lens consists of four components. First component is made of single biconvex and biconcave lenses, second component is a single biconvex lens, third component is glued from biconvex and biconcave lenses, The fourth component is the single meniscus whose concave surface faces the image and whose radius of curvature of the convex surface is greater than the radius of curvature of the concave surface. Following ratios are met: |R| = |R|; |R| = |R| = |R|; |R| < |R|, where Ri is radius of curvature of i-spherical optical surface along beam path.EFFECT: technical result is increase of relative opening and increase of spectral range of working wavelengths with high quality of image.1 cl, 1 dwg, 2 tbl

Description

The invention relates to optical instrumentation and can be used in various optical systems operating both in the visible and in the infrared ranges of the spectrum, in particular in cameras operating with a receiving matrix.

Known fast lens described in patent RU No. 2351967, IPC G02B 9/60, 11/30, 13/14, publ. 04/10/2009, consisting of four components along the rays. The first component is positive and is made of single biconvex and concave flat lenses. The second is a single positive meniscus with a convex surface facing the image. The third is positive, glued from a biconvex and concave plane lenses. The fourth is the positive meniscus turned by the concavity to the image, in which the radius of curvature of the convex surface is greater than the radius of curvature of the concave surface. In the first component, the radius of curvature of the second surface of the biconvex lens is larger in magnitude than the radius of curvature of the first surface of the negative lens, and the radius of curvature of the convex surface of the meniscus of the second component is equal to the radius of curvature of the first surface of the negative lens of the first component. Each biconvex lens of the first and third components is symmetrical and made of one material. However, this aperture lens has an insufficient relative aperture of 1: 1.1 and an insufficiently large spectral range of working wavelengths from 650 nm to 900 nm.

The closest analogue to the claimed technical solution is a fast lens described in patent RU No. 2396581, IPC G02B 9/60, 13/14, publ. 08/10/2010, consisting of four components. The first component is made of single biconvex and concave flat lenses, the second is a single flat-convex lens facing the object with a plane, the third is positive, glued from a biconvex and biconcave lens, the fourth is a positive meniscus that has a concavity to the image, the radius of curvature of the convex surface is greater than the radius of curvature concave surface. In the first component, the radius of curvature of the second surface of the biconvex lens is larger in magnitude than the radius of curvature of the first surface of the concave lens. Each biconvex lens is symmetrical. The refractive index of the fourth component is more than 1.64 and less than 1.9 for the line e, the refractive index of the biconvex lens of the third component is more than 1.56 and less than 1.63 for the line e and less than the refractive index of the biconvex lens of the first component. The condition is satisfied:

- фокусное расстояние объектива;Where:

- focal length of the lens;

d ₄ - the distance between the first and second components.

However, this aperture lens has an insufficient relative aperture of 1: 1.08 and an insufficiently large spectral range of working wavelengths from 650 nm to 900 nm.

The objective of the invention is the creation of a fast lens with enhanced performance with high image quality.

The technical result is an increase in the relative aperture and an increase in the spectral range of the working wavelengths with high image quality.

This is achieved by the fact that in a fast lens consisting of four components, the first of which is made of single biconvex and negative lenses along the rays, the second component is a single positive lens, the third component is glued from biconvex and negative lenses, and the fourth component is concave the image is a single meniscus whose radius of curvature of the convex surface is greater than the radius of curvature of the concave surface, moreover, the biconvex lens of the third component is symmetrical, in contrast to the known one, the negative lens of the first component is biconcave, the second component is made in the form of a biconvex lens, the negative lens of the third component made biconcave and conditions are:

| R ₁ | = | R ₃ |; | R ₂ | = | R ₅ | = | R ₉ |; | R ₁ | <| R ₂ |,

where: Ri is the radius of curvature of i - a spherical optical surface along the rays.

The drawing shows an optical diagram of the proposed aperture lens. A fast lens consists of six lenses in four components. The first component along the rays consists of a single biconvex lens 1 and a biconcave lens 2. The second component is made in the form of a biconvex lens 3. The third component is glued from a biconvex lens 4 and a biconcave lens 5. The biconvex lens 4 is symmetrical with equal curvature radii of both surfaces | R ₇ | = | R ₈ |. The fourth component is a single meniscus 6 turned by a concavity to the image, in which the radius of curvature of the convex surface R _{10 is} greater than the radius of curvature R _{11 of the} concave surface. Behind the meniscus 6 is a light filter 7, and behind it is a plane-parallel plate 8, which can be a protective glass. The aperture diaphragm is located at a distance of 3 mm in front of the lens 3, but can be located in another place.

The proposed optical system works like a lens collecting from infinity. The luminous flux from an object located at infinity falls into the lens, where the light filter 7 and plane-parallel plate 8 pass through the lenses 1, 2, 3, 4, 5, 6 and forms an image of the object in the plane of the best setup in which the optical radiation receiver is installed (not shown). In accordance with the proposed solution, the design of the fast lens was calculated, corrected in the spectral range from 650 to 1000 nm for the main wavelength of 766.49 nm.

In the table. 1 shows aberrations for a wavelength of 766.49 nm of the proposed aperture lens.

The design parameters of the proposed aperture lens are shown in table 2.

Characteristics of the calculated lens:

focal length 67.09 mm back focal length 4.865 mm relative hole 1: 0.99 angular field in the space of objects 5 deg. 13 minutes

Thus, as a result of the proposed solution, a technical result is obtained: a fast lens with an increased relative aperture of 1: 0.99 is created, operating in the spectral range from 650 nm to 1000 nm.

Claims (5)

A fast lens consisting of four components, the first of which is made of single biconvex and negative lenses along the rays, the second component is a single positive lens, the third component is glued from biconvex and negative lenses, and the fourth component is a single meniscus that is concave to the image, whose radius of curvature of the convex surface is greater than the radius of curvature of the concave surface, and the biconvex lens of the third component is symmetrical, characterized in that the negative lens of the first component is biconcave, the second component is made in the form of a biconvex lens, the negative lens of the third component is biconcave and the following conditions are met: | R ₁ | = | R ₃ | | R ₂ | = | R ₅ | = | R ₉ |; | R ₁ | <| R ₂ | where Ri is the radius of curvature of the i-spherical optical surface along the rays.

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