RU191915U1 - Ocular with a remote exit pupil - Google Patents

Abstract

The eyepiece can be used in visual observation optical instruments and sights. The eyepiece contains the first component of glued biconcave and biconvex lenses, the second component containing a negative meniscus facing concavity to the image space, glued with a biconvex lens, and the third glued component is made of negative meniscus facing concavity to the image space, and a positive lens. The ratios indicated in the claims are fulfilled. EFFECT: providing an exit pupil of at least 1.2f 'of the eyepiece, anterior segment of at least 0.4f' or with a focus of 22 mm at least 8 mm from the top of the first surface, and an image contrast at a frequency of N = 25 l / mm of at least 40% the whole field. 4 ill.

Description

The proposed utility model relates to optical instrumentation, namely to visual observational optical instruments and sights.

Most existing eyepieces of observing instruments are based on relatively simple and well-known optical schemes (for example, Huygens, Kölner, Erfle, and other systems [1, 2], which are characterized by satisfactory image quality at moderate angular field values (15–30 °), offset values (0.5f '), exit pupil size and posterior segment.

The main disadvantage of such eyepieces is the inability to achieve the removal of the exit pupil to (1 ÷ 1.2) f 'relative to the last lens and increase the anterior segment while ensuring high image quality throughout the field used in night vision devices based on modern high-resolution image intensifier tubes.

Closest to the claimed utility model is an eyepiece [3], which consists of three components, the first of which along the rays, a two-lens glued from a biconcave and biconvex lens, the second component is a biconvex single lens, and the third is a two-lens glued, consisting of a biconvex lens and negative meniscus convex to the image.

4 мм, большое угловое поле зрения (60°).The eyepiece has an exit pupil

4 mm, large angular field of view (60 °).

The disadvantages include a small exit pupil less than 0.8f ', a small front segment, taking into account the deflection of the anterior surface of the eyepiece and image quality that does not correspond to what is required for night vision devices.

The main task that the proposed utility model aims to solve is to remove the exit pupil by at least 1.2f 'of the eyepiece, the front segment should not be less than 0.4f' or with a focus of 22 mm at least 8 mm from the top of the first surface of the eyepiece and contrast image at a frequency of N = 25 l / mm should be at least 40% throughout the field.

To solve this problem, an eyepiece is proposed, which, like the prototype, contains three components, the first of which is glued two-lens, consisting of a biconcave and biconvex lens, the second is a single lens, and the third is a glued lens.

Unlike the prototype, the second lens is glued from a negative meniscus facing concavity to the image space, and a biconvex positive lens, the third contains a negative meniscus facing concavity to the image space, and a positive lens.

In this case, the optical powers of the components are related by the relations:

0.3≤ϕ ₁ /ϕ≤0.45; 0.48≤ϕ ₂ /ϕ≤0.56;

where ϕ is the optical power of the entire system, ϕ _i is the optical power of the ith component, the positive lenses of the first and second components and the negative lens of the third component are made of glass with a refractive index of 1.7≤n≤1.8 and a dispersion coefficient of 44≤ν≤52, and negative lenses of the first and second components are made of glass with a refractive index of 1.72≤n≤1.77 and a dispersion coefficient of 27≤ν≤30.

Thus, due to the implementation of the second component glued together, and the components from the above ratios, it was possible to minimize chromatic aberrations in the center and in the field, astigmatism and curvature, ensuring the required image quality: the image contrast in the center and in the field for a frequency of N = 25 l / mm less than 40%, while the exit pupil is 1.2f 'away, and the anterior segment from the top of the first surface of the eyepiece is at least 8 mm and the diameter of the exit pupil is increased to 5 mm.

5 мм при высоком качестве изображения в центре и по полю.Thus, the technical result was achieved, consisting in increasing the removal of the exit pupil to 1.2f ', the front segment of at least 8 mm, the diameter of the exit pupil to

5 mm with high image quality in the center and across the field.

The essence of the proposed utility model is illustrated by drawings, where

in FIG. 1 - presents an optical diagram of the eyepiece,

in FIG. 2 is a graph of transverse aberrations,

in FIG. 3 - presents a graph of the frequency-contrast characteristics,

in FIG. 4 - presents a graph of aberrations of the main rays.

The inventive eyepiece with a remote exit pupil contains three components.

The first component I contains a glued lens, consisting of a negative biconcave 1 and a positive biconvex 2 lenses.

The second component II consists of an additionally placed negative meniscus 3, turned concavity into the image space, and a positive biconvex lens 4.

The third component III contains a negative meniscus 5, facing concavity in the space of the image and the positive lens 6.

In addition, the optical powers of the components are related by the relations:

,0.3≤ϕ ₁ /ϕ≤0.45; 0.48≤ϕ ₂ /ϕ≤0.56;

,

the positive lenses of the first and second components and the negative lens of the third component are made of glass with a refractive index of 1.7≤n≤1.8 and a dispersion coefficient of 44≤ν≤52, and the negative lenses of the first and second components are made of glass with a refractive index of 1.72≤n≤1.77 and the dispersion coefficient of 27≤ν≤30.

The proposed lens works as follows.

Rays from the object of observation pass through the first component I, introducing spherical aberration, astigmatism and curvature, component II corrects the spherical aberration, partially compensating for astigmatism and curvature, and component III builds an image at infinity, compensating for the residual aberrations.

Due to the above ratios of the optical powers of the components, the exit pupil can be removed from the ophthalmic lens by at least 1.2 f '. The size of the front segment is increased.

Thanks to the use of the proposed technical solution, an eyepiece with an exit pupil of 1.2f 'with a focal length f' = 22 mm, an exit pupil size of 5 mm, an anterior segment, taking into account the arrow deflection of the anterior surface of the eyepiece is more than 8 mm, image field 2Y '= 12 was calculated mm

Thus, the proposed eyepiece has a large projection of the exit pupil, the anterior segment and the size of the exit pupil, while the high image quality throughout the field meets the requirements of modern night vision devices.

The calculation results are given in the Appendix, which gives the design parameters and optical characteristics of the eyepiece.

APPENDIX

System:

Focal length mm 22.36 Numerical aperture in item space 0.4042 Diameter of exit pupil, mm 5.0 Diameter of the item, mm 12.0000

Spectral characteristics

Design parameters of the optical system

Polychromatic Frequency Contrast Characteristic Frequency response in the calculated eyepiece over the entire field for a frequency of 25 l / mm not less than 40%.

Thus, in the proposed eyepiece, the exit pupil extension is increased to 1.2f ', its size is up to 5 mm and the front segment, taking into account the arrow deflection of the front surface of the eyepiece with high image quality throughout the field.

INFORMATION SOURCES

1. Reference designer of optical-mechanical devices. Ed. V.A. Panova. L. Mechanical engineering. 1980 year

2. Begunov M.M. Composition of optical systems. L. Mechanical engineering. 1989 year

3. Russian Federation, patent for invention No. 2229150, IPC G02B 25/00, 2004 - prototype.

Claims (3)

An eyepiece with a remote exit pupil containing three components, the first of which consists of glued negative biconcave and positive biconvex lenses, the second component contains a positive biconvex lens, and the third one glued of two lenses, characterized in that the negative meniscus is additionally placed in the second component, facing concavity to the image space, glued with a positive biconvex lens, and the third glued component is made of a negative meniscus, turned concave resistance to the image space and the positive lens, the following conditions being met: 0.3≤ϕ ₁ /ϕ≤0.45; 0.48≤ϕ ₂ /ϕ≤0.56;

, where ϕ is the optical power of the entire system, ϕ _i is the optical power of the ith component, in addition, the positive lenses of the first and second components and the negative lens of the third component are made of glass with a refractive index of 1.7≤n≤1.8 and a dispersion coefficient of 44≤ν≤ 52, and the negative lenses of the first and second components are made of glass with a refractive index of 1.72≤n≤1.77 and a dispersion coefficient of 27≤ν≤30.

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