RU2548745C1 - Wide-angle eyepiece - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: wide-angle eyepiece comprises five components. The first from the plane of the entrance pupil the component 1 - is positive, is glued together from plano-concave 6 and plano-convex 7 lenses and faces with a concave surface towards the plane of the entrance pupil. The second component 2 - is the plano-convex lens facing with a flat surface towards the plane of the entrance pupil. The thrird component 3 - is the plano-convex lens facing with a convex surface towards the plane of the entrance pupil. The fourth component 4 - is positive, is glued together using plano-convex 8 and plano-concave 9 lenses and faces with a convex surface towards the plane of the entrance pupil. The fifth component 5 - is negative, is glued together from biconcave 10 and biconvex 11 lenses. Lenses 6, 9 and 11 are made of heavy flint with identical index of refraction greater than 1.8, and the others - from heavy krone with identical index of refraction which is higher than 1.7.

EFFECT: increase of angular field of vision, increase of distance to the output pupil and improvement of producibility of eyepiece.

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Description

The invention relates to the field of optical instrumentation and can be used in astronomical telescopes for visual observation and photographing, in telescopes, binoculars and other observational devices.

For comfortable viewing, wide-angle eyepieces with a large angular field of view of at least 80 ° are required.

Known for the wide-angle eyepiece OKSH-24 AL5.923.598, used in telescopes manufactured by the Novosibirsk Instrument-Making Plant, having an angular field in the image space of 80 °. The eyepiece contains 5 components: the first is glued positive and scattering menisci, the second is a plano-convex lens facing the exit pupil with a flat surface, the third is a glued meniscus and a biconvex lens, the fourth is a plano-convex lens, the fifth is a biconcave lens (Specifications TU3-2005 AL5 .923.631 TU, 2005).

The specified eyepiece does not have a sufficiently large angular field of view, a small removal of the exit pupil, equal to 12 mm (0.5 focal length). In addition, six grades of glass are required to make such an eyepiece.

The closest in technical essence to the claimed - the prototype is a wide-angle eyepiece according to US patent No. 4747675 from 05/31/1988, G02B 25/00, 25/04. The wide-eyepiece according to option 3 contains five components sequentially located along the optical axis from the plane of the exit pupil, of which the first is positive, made of two lenses glued together, facing a concave surface to the plane of the entrance pupil, the second and third components are single lenses, the fourth - positive, made of two lenses glued together, facing a convex surface to the plane of the entrance pupil, and the fifth is negative, made of two lenses glued together, ervaya of which - biconcave, the 1st lens first component 2nd component of the fourth lens and the 2nd fifth lens component made of heavy flint one mark, and the others - heavy Kroon.

In this prototype eyepiece, the first component is made of biconcave and biconvex lenses and faces with a concave surface to the plane of the entrance pupil, the second and third components are made in the form of biconvex lenses, the fourth component is made of biconvex and convex-concave lenses, and the second lens of the fifth component is convex concave. For the manufacture of lenses used a heavy flint with a refractive index of 1.71 and a heavy crown of two brands. A heavy crown with a refractive index of 1.71 was used for the 1st lens of the fifth component, and a heavy crown with a refractive index of 1.62 was used for the second and third components, the 2nd lens of the first and 1st lens of the fourth component.

The prototype also has an insufficiently large angular field of view (80-90 °) and a small distance of the exit pupil equal to 0.6 focal length. In addition, the eyepiece is made of glass of three grades, the lens surfaces are convex or concave, which represents a certain technological complexity.

The objective of the invention is the creation of a wide-angle eyepiece, providing the following technical results: an increase in the angular field of view, an increase in the removal of the exit pupil and an increase in the manufacturability of the eyepiece.

The indicated technical results are achieved by the following technical solution of the eyepiece. The wide-angle eyepiece, like the prototype, contains five optically coupled components, of which the first component from the plane of the entrance pupil (in the opposite direction of rays) is a positive component made of two lenses glued together, facing a concave surface to the plane of the entrance pupil, the second and third components - single lenses, the fourth is positive, made of two lenses glued together, facing a convex surface to the plane of the entrance pupil, and the fifth is negative, made of two glued together INZ, the first of which - biconcave, the 1st lens first component 2nd component of the fourth lens and the 2nd fifth lens component made of heavy flint one mark, and the others - heavy Kroon. In contrast to the prototype, in the proposed eyepiece, the first component is made of a plano-concave and plano-convex lenses, the second component is made as a plano-convex lens facing a flat surface to the plane of the entrance pupil, the third component is in the form of a plano-convex lens facing a convex surface to the plane of the entrance pupil, the fourth component made of plano-convex and plano-concave lenses, and the second lens of the fifth component is biconvex, and a heavy flint with a refractive index of at least 1 is used , 8 and heavy crowns of the same brand with a refractive index of at least 1.7.

As an example of a specific implementation of the wide-angle eyepiece, an eyepiece with an angle of view of 100 ° is calculated. The proposed solution is illustrated by the following graphic materials.

Figure 1 presents the optical diagram of the eyepiece.

, $$Z_m^{\text{'}}$$

(мм). По оси ординат отложен размер изображения Y′ (град).Figure 2 shows a graph of astigmatism of the eyepiece. The abscissa shows astigmatic segments $$Z_s^{\text{'}\text{'}}$$

, $$Z_m^{\text{'}\text{'}}$$

(mm). The ordinate shows the image size Y ′ (degrees).

Figure 3 shows a graph of the distortion of the eyepiece. The abscissa shows the relative distortion in Δу ′ in%. The ordinate shows the image size Y ′ (degrees).

The wide-angle eyepiece (FIG. 1) contains five optically coupled components. The first component 1 from the plane of the entrance pupil is positive, glued from plane-concave 6 and plane-convex 7 lenses and faces with a concave surface to the plane of the entrance pupil. The second component 2 is a plano-convex lens facing a flat surface to the plane of the entrance pupil. The third component 3 is a plano-convex lens facing a convex surface to the plane of the entrance pupil. The fourth component 4 is positive, glued from plane-convex 8 and plane-concave 9 lenses and faces with a convex surface to the plane of the entrance pupil. The fifth component 5 is negative, glued from biconcave 10 and biconvex 11 lenses. Between components 4 and 5 is a field diaphragm. Lenses 6, 9 and 11 are made of heavy flint of the same brand with the same refractive index of more than 1.8, and the rest are made of heavy crown of the same brand with the same refractive index of more than 1.7.

The eyepiece has the following characteristics:

- focal length - 12.5 mm;

- relative aperture - 1: 5;

- working spectral range - 0.43-0.7 microns;

- the main wavelength is 0.546 microns;

- angular field of view in the space of objects - 100 °;

- maximum light diameter - 47.5 mm;

- removal of the entrance pupil - 10 mm.

The eyepiece works as follows. The radiation coming from each point of the subject plane is directed by the components 1-5 of the eyepiece to the exit pupil. Components 1, 2 bend wide beams coming from the entrance pupil, aligning monochromatic aberrations with residual under-corrected curvature, astigmatism and distortion. Components 3, 4 compensate for monochromatic aberration, correcting astigmatism and distortion. Component 5, correcting the chromatic aberrations of position and magnification, corrects the curvature, telecentrically mates the planes of the entrance and exit pupils, ensuring their required removal.

From the graphs (figure 2, 3) it follows that within the angular field of view of 100 ° the astigmatism of the eyepiece does not exceed 0.1 mm, and the distortion does not exceed 15%.

Increased in comparison with the prototype, the removal of the entrance pupil to 10 mm (0.8 focal length of the eyepiece) allows the observer to comfortably place the pupil of the eye in the entrance pupil of the eyepiece and examine the entire field of view of the eyepiece. The eyepiece lenses are made of two grades of glass, part of the lens surfaces are flat. Compared with the prototype, such an eyepiece is easier to manufacture.

As a result of the implementation of the proposed technical solution, an eyepiece was obtained having a very wide angular field of view - 100 °, a sufficiently large removal of the entrance pupil - 10 mm, and at the same time a simple technological design suitable for implementation in mass production.

Thus, in comparison with the prototype of the claimed invention allows to increase the angular field of view, increase the removal of the exit pupil and increase the manufacturability of the eyepiece.

Claims (1)

A wide-angle eyepiece containing five components, of which the first component from the plane of the entrance pupil is positive, made of two lenses glued together, facing a concave surface to the plane of the entrance pupil, the second and third components are single lenses, the fourth is positive, made of glued between two lenses, convex surface facing the plane of the entrance pupil, and the fifth negative, made of two lenses glued together, the first of which is biconcave, while the 1st lens the first component, the 2nd lens of the fourth component and the 2nd lens of the fifth component are made of heavy flint of the same brand, and the rest are made of heavy crown, characterized in that the first component is made of flat-concave and flat-convex lenses, the second component is made in the form of a flat-convex lens facing a plane surface to the plane of the entrance pupil, the third component is in the form of a plano-convex lens, facing a convex surface to the plane of the entrance pupil, the fourth component is made of plane-convex and plane-concave lenses and the second lens of the fifth component is biconvex, using a heavy flint with a refractive index of at least 1.8 and a heavy crown of the same brand with a refractive index of at least 1.7.

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