RU2676554C1 - Wide angle lens - Google Patents

Abstract

FIELD: optics.

SUBSTANCE: invention can be used as a photographic objective. Wide-angle lens consists of two optical components separated by an air gap. First component contains a negative meniscus facing the convex side to the plane of objects, a biconvex lens, a negative and positive meniscus facing the convex side to the plane of objects. Second component contains a meniscus glued from biconcave and biconvex lenses, with the convex side facing the image plane, positive and negative menisci, facing the convex side to the image plane. There are relations: 1.59<n1=n2=n3=n6=n7<1.64, 1.692<n4=n5<1.73, 1.55<n8<1.59, where n1, n2, n3, n4, n5, n6, n7 and n8 – refractive indices of the material along the rays of the first, second, third, fourth, fifth, sixth, seventh and eighth lenses, respectively, for the spectrum line D.

EFFECT: increasing the relative aperture and improving processability.

1 cl, 2 dwg, 2 tbl

Description

The invention relates to optical instrumentation and can be used as a photographic lens.

Known photographic lens described in US patent 4211472, published 08.07.1980, IPC G02B 11/30. A photographic lens consists of two components separated by an air gap, the first of which along the rays consists of a negative meniscus, with its convex side facing the plane of objects, a glued meniscus, consisting of a biconvex lens and a biconcave lens, convex towards the plane of objects, the second component consists of a meniscus with the convex side facing the image plane, a glued meniscus consisting along the beam of a biconcave lens and a biconvex lens, aschennogo convex side to the object plane, a negative meniscus facing the convex side to the object plane. However, this object has an insufficient ratio of the back focal length to the focal length Bf / f '= 0.615, as well as a lack of manufacturability, since all the radii of the optical surfaces of this lens are different.

The closest analogue of the claimed technical solution is a photographic lens, described in patent US 3410632, published 05.24.1965, IPC G02B 9/64, figure 2. The lens consists of two components separated by an air gap, the first of which along the rays consists of a plano-convex positive lens with a convex side facing the plane of the objects, a negative meniscus with a convex side facing the plane of the objects, a biconvex lens, a meniscus facing the convex side of the plane of objects, the second Symbol Item composed of a cemented meniscus along the beam consisting of a biconcave lens and a biconvex lens facing the convex surface to the image plane, a positive meniscus convex side facing to the image plane. However, this lens has an insufficient relative aperture D: f '= 1: 4.0 and insufficient manufacturability, since all the radii of the optical surfaces of this lens are different.

The task of the invention is to provide a lens with enhanced performance.

EFFECT: increased relative aperture and increased manufacturability.

This is achieved by the fact that in a wide-angle lens, consisting of two optical components separated by an air gap, in which the first optical component is made up of the positive lens, the negative meniscus, the convex side facing the objects plane, and the meniscus facing the convex side to plane of objects, the second optical component is made along the rays from the meniscus, glued from a biconcave and biconvex lens, facing the convex side to In contrast to the known one, in the first optical component a negative meniscus is added, which is installed first along the rays and faces with a convex side to the plane of objects, a positive lens following a negative meniscus is made biconvex , the meniscus installed in front of the air gap is positive, and a negative meniscus is added in the second optical component, which was installed last along the rays positive meniscus and facing the convex side to the image plane, and the following relations:

1.59 <n1 = n2 = n3 = n6 = n7 = 1.64,

1.692 <n4 = n5 <1.73,

1.55 <n8 <1.59,

where n1, n2, n3, n4, n5, n6, n7 and n8 are the refractive indices of the material along the rays of the first, second, third, fourth, fifth, sixth, seventh and eighth lenses, respectively, for the spectrum line D.

In FIG. 1 is an optical diagram of a wide angle lens; FIG. 2 shows the frequency-contrast characteristic of a fast lens for indicators of 10 l / mm and 30 l / mm.

The wide-angle lens (Fig. 1) consists of two optical components along the rays, the first of which consists of a negative meniscus 1 facing a convex surface to the plane of objects, a biconvex lens 2, a negative meniscus 3 facing a concave side to the image plane, and positive meniscus 4 facing a convex surface to the plane of objects. The second optical component consists of a glued meniscus consisting of a biconcave negative lens 5 and a biconvex lens 6, convex side to the image plane, a positive meniscus 7, convex side to the image plane, and a negative meniscus 8, convex side to the image plane . The aperture diaphragm is located between the positive meniscus 4 of the first optical component and the biconcave negative lens 5 of the second optical component at a distance of 5.5 mm.

Wide-angle lens works as follows.

The luminous flux emanating from the plane of objects located at infinity passes through a wide-angle lens in the following sequence. First, the light flux passes through the negative meniscus 1, the biconvex lens 2, the negative meniscus 3, the positive meniscus 4, through the biconcave lens 5, glued to the biconvex lens 6 and through the positive meniscus 7 and the negative meniscus 8. Next, the light flux passing through all the optical elements wide-angle lens, builds an image in the plane of the best setting in which the photodetector is located (not shown in Fig.). The focus of the lens at a finite distance is carried out by moving the entire optical circuit.

As a specific example of the invention, a wide-angle lens is calculated, corrected in the spectral range from 435 nm to 656 nm with the structural data presented in table. one.

The calculated fast lens has the following characteristics:

The focal length of the lens f ' 28.15 mm Relative hole 1: 2.8 Angular field in the space of objects 75 deg. Linear field in image space 2Y '= 43.26 mm Back focal length 38.45 mm

For this lens, there are relations:

1.59 <n1 = n2 = n3 = n6 = n7 = 1.613094 <1.64,

1.692 <n4 = n5 = 1.717416 <1.73,

1.55 <n8 = 1.575020 <1.59,

Table 2 shows the wavelengths and weights of the proposed wide-angle lens for 10 l / mm and 30 l / mm for a specific embodiment.

The proposed wide-angle lens has the same modulus of the radii of the spherical optical surfaces of the biconvex lens 6 included in the glued meniscus of the second component, which characterizes its high manufacturability.

Thus, a technical result is obtained: a high-aperture lens with a higher relative aperture is created, with increased manufacturability.

Claims (5)

A wide-angle lens, consisting of two optical components separated by an air gap, in which the first optical component is made up of the positive lens, the negative meniscus with the convex side facing the objects plane, the meniscus with the convex side facing the objects plane, and the second optical component made along the rays from the meniscus glued from a biconcave and biconvex lens, convex side to the image plane, and put a meniscus with a convex side facing the image plane, characterized in that a negative meniscus is added in the first optical component, which is installed first along the rays and convex towards the plane of objects, the positive lens following the negative meniscus is biconvex, the meniscus placed in front of the air gap is made positive, and in the second optical component a negative meniscus is added, installed last along the rays behind the positive meniscus and the sample with the convex side to the plane of the images, and there are relations: 1.59 <n1 = n2 = n3 = n6 = n7 <1.64, 1.692 <n4 = n5 <1.73, 1.55 <n8 <1.59, where n1, n2, n3, n4, n5, n6, n7 and n8 are the refractive indices of the material along the rays of the first, second, third, fourth, fifth, sixth, seventh and eighth lenses, respectively, for the spectrum line D.

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