RU2737029C1 - Large aperture lens - Google Patents

Abstract

FIELD: optics.

SUBSTANCE: lens can be used in optical systems operating in both visible and infrared spectral ranges. Lens consists of two components. First component along the beam path consists of three single lenses - a biconvex lens, a biconcave lens and a positive meniscus, whose concave side faces the image. Second component consists of a single biconvex lens and a glued lens of a biconvex lens and a biconcave lens, wherein in the glued lens, the refractive index of the biconvex lens material is less than the biconcave lens material refractive index for the e line.

EFFECT: technical result is high aperture ratio with high quality of image in wide spectral range.

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 infrared ranges of the spectrum.

Known high-aperture lens described in US patent No. 2861500, publ. 1958, consisting of six lenses in the course of the rays: the first is biconvex, the second is biconcave, the third is a positive meniscus, concave to the image, the fourth is a positive meniscus, concave to the image, the fifth is a negative meniscus, concave to the image, and the sixth is biconvex. The aperture diaphragm is located after the fifth lens. However, this lens has an insufficient aperture ratio of 1: 1.2.

The closest analogue to the claimed technical solution is a high-aperture lens described in US patent No. 2541484, publ. 1951, fig. 1, fig. 2, Fig. 3, consisting of two components, the first component along the path of the rays is a three-lens made of a biconvex lens glued to a biconcave lens and a single positive meniscus facing the image with a concavity; the second component also contains glued biconvex and biconcave lenses and a single negative meniscus convex to the image. Moreover, in the second component in the glued element, the refractive index of the biconvex lens is greater than the refractive index of the biconcave lens. However, this lens has an insufficient aperture ratio of 1: 1.5.

The objective of the claimed invention is to create a high-aperture lens with improved performance and high image quality.

The technical result is an increase in the relative aperture with high image quality in an extended spectral range.

This is achieved by the fact that in a high-aperture lens, consisting of two components, the first of which is three-lens, containing biconvex and biconcave lenses along the ray path and a single positive meniscus facing the image with concavity; the second component is made glued from a biconvex and biconcave lenses and a single lens, in contrast to the known one, in the first component all lenses are single, in the second component a single lens is made in the form of a biconvex and along the path of the rays is located in front of the glued lens, in addition, in the glued lens the indicator the refractive index of the biconvex lens material is less than the refractive index of the biconcave lens material for line e.

The drawing shows the optical diagram of the proposed lens.

The high-aperture lens consists of two components, the first component of a three-lens element made of a single biconvex lens 1, a single biconcave lens 2 and a single positive meniscus 3, concavely facing the image. The second component consists of a single biconvex lens 4 and a glued lens consisting of a biconvex lens 5 and a biconcave lens 6 along the path of the rays; in addition, a light filter 7 and a protective glass 8 are located behind the biconvex lens 6. The aperture diaphragm is located behind the meniscus 3 at a distance of 10 mm. , but may be located in another place.

The proposed optical system works like a lens collecting from infinity.

A high-aperture lens works as follows: the light flux from an object located at infinity enters the lens, where it passes through lenses 1, 2, 3, 4, 5, 6, light filter 7 and protective glass 8 and forms an image of the object in the plane of the best installation, in which a receiver of optical radiation (not shown) is installed.

In accordance with the proposed solution, a high-aperture objective was calculated, corrected in the spectral range from 580 to 950 nm for the fundamental wavelength of 800 nm.

Calculated lens characteristics:

focal length 67.77 mm posterior focal segment 3,446 mm posterior focal segment without light filter and protective glass 21.6 mm relative aperture 1: 1.1 angular field in object space 5 deg. 10 min.

Table 1 shows the aberrations for a wavelength of 800 nm of the proposed high-aperture objective.

The design parameters of the proposed fast lens are shown in Table 2.

Thus, as a result of the proposed solution, a technical result was obtained: a high-aperture lens with an increased relative aperture of 1: 1.1 was created, while maintaining high image quality in the spectral range from 580 nm to 950 nm.

Claims (1)

High-aperture lens, consisting of two components, the first of which is three-lens, containing biconvex and biconcave lenses along the path of rays, and a single positive meniscus facing the image with a concavity; the second component is made glued from a biconvex and biconcave lenses, and a single lens, characterized in that in the first component all lenses are single, in the second component a single lens is made in the form of a biconvex and along the path of the rays is located in front of the glued lens, in addition, in the glued lens the indicator the refractive index of the biconvex lens material is less than the refractive index of the biconcave lens material for line e.

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