RU162339U1 - TWO-LENS LENS - Google Patents

Abstract

1. A two-lens lens consisting of a biconvex lens located along the rays and a negative meniscus convex to the image, the radii of the biconvex lens being equal in absolute value, and the ratio of the first meniscus lens radius to its second radius less than 0.8, differing the fact that there are relations: 1.3 <n <1.68; 1.5 <n <1.66; where n and n are the refractive indices of the material of the first and second lenses along the rays for line e.2. A two-lens lens according to claim 1, characterized in that the lenses are single. 3. A two-lens lens according to claim 2, characterized in that the lenses are glued.

Description

The proposed utility model relates to optical instrumentation and can be used in various optical systems, for example, in visual and infrared systems.

Known two-lens lens - achromat, described in the application FR No. 2025476, IPC G02B 13/00, 5/00, publ. 1970, operating in the IR range from 8 to 14 μm, consisting of a single biconvex lens and a negative meniscus, convex to the image. The lenses of the lens are made of CsBr and ZnS materials with refractive indices of 1.66251 and 2.1986. The lens has a small focal length of 100 mm and lack of manufacturability, as the manufacture requires the use of different reference test glasses for each optical surface.

The closest analogue to the claimed technical solution is a two-lens lens described in patent RU No. 2316795, IPC G02B 9/10, publ. 02/10/2008, consisting of a biconvex lens located along the beam and a negative meniscus convex to the image in which both lenses are made of optical glass transparent in the visible and near infrared spectral ranges, the radii of the biconvex lens are equal in absolute value, the ratio of the first along the rays of the radius of the meniscus lens to its second radius is less than 0.8 and there are relations:

1.46 <n ₁ <1.63;

1.66 <n ₂ <1.78;

where n ₁ and n ₂ are the refractive indices of the material of the first and second lenses along the rays.

This lens does not have sufficiently large focal lengths equal to 399.55 mm and the diameter of the entrance pupil is 57.5 mm.

The objective of the claimed utility model is the creation of a technological lens with enhanced performance.

The technical result is an increase in the focal length and diameter of the entrance pupil with high technology and high image quality.

This is achieved by the fact that in a two-lens lens, consisting of a biconvex lens located along the rays and a negative meniscus convex to the image, in which the biconvex lens radii are equal in absolute value, the ratio of the first meniscus lens radius to the second radius is less than 0 , 8 in contrast to the known, the following relations hold:

1.3 <n ₁ <1.68;

1.5 <n ₂ <1.66;

where n ₁ and n ₂ are the refractive indices of the material of the first and second lenses along the rays. In addition, in a two-lens lens, the lenses may be single or bonded.

In FIG. 1 is an optical diagram of the proposed single-lens lens, and FIG. 2 - with glued.

.A two-lens lens (Fig. 1 and Fig. 2) consists of biconvex lens 1 located along the rays and a negative meniscus 2, convex to the image. Lenses 1 and 2 can be single (Fig. 1) and glued (Fig. 2). The radii of the biconvex lens 1 are equal in absolute value | R ₁ | = | R ₂ |, and the ratio of the first along the rays of the radius of the meniscus lens 2 to its second radius is less than 0.8,

.

The lens operates as follows, the light flux from an object located at infinity enters the lens, where it passes through lenses 1, 2 and forms an image of the object in the plane of the best setting in which the optical radiation receiver (not shown) is installed.

In accordance with the proposed solution, two two-lens lenses are designed.

The first lens is fixed simultaneously for λ = 625 nm and for λ = 900 nm and achromatized for these wavelengths. The lens can work as a collimator. The lens operates in the visible and near infrared spectral range.

The design parameters of the first lens are given in table. one

The entrance pupil is located on the first optical surface of the lens, but may be in another place.

Characteristics of the calculated first lens:

focal length 1200 mm entrance pupil diameter 106 mm field of view angle 2 deg. 20 minutes.

The lens has the following aberrations for λ = 625 nm:

- transverse spherical aberration for a point on the axis of not more than 0.0141 mm

- transverse aberration of a wide inclined beam in the meridional section for the field of view 2W = 2 deg. 20 minutes. no more than -0.0353 mm

- transverse aberration of a wide inclined beam in the sagittal section for the field of view 2W = 2 deg. 20 min no more than 0,0062 mm

- meridional astigmatic segment X _m not more than 1.009 mm

- sagittal astigmatic segment X _s not more than - 0.459 mm

- distortion no more than 0,00043%

In the proposed utility model:

| R ₁ | = | R ₂ | = 616,263;

1.3 <n ₁ = 1.4485 <1.68

1.5 <n ₂ = 1.652188 <1.66

where R ₁ and R ₂ are the radii of the first and second optical surfaces along the rays;

n ₁ and n ₂ are the refractive indices of the material of the first and second lenses along the rays for line e.

The ratio of the first along the rays of the radius of the meniscus lens to its second radius is 0.4602.

The second lens is fixed simultaneously for λ = 625 nm and for λ = 900 nm and achromatized for these wavelengths and can also work as a collimator. The lens operates in the visible and near infrared spectral range.

The design parameters of the second lens are given in table. 2.

The entrance pupil is located on the first optical surface of the second lens, but can be located in another place.

Characteristics of the calculated second lens:

focal length 1200 mm entrance pupil diameter 106 mm field of view angle 2 deg. 20 minutes.

The lens has the following aberrations for λ = 625 nm:

- transverse spherical aberration for a point on the axis of not more than 0.0565 mm

- transverse aberration of a wide inclined beam in the meridional section for the field of view 2W = 2 deg. 20 minutes. no more - 0,1241 mm

- transverse aberration of a wide inclined beam in the sagittal section for the field of view 2W = 2 deg. 20 min no more than 0,0371 mm

- meridional astigmatic segment X _m not more than - 0.938 mm

- sagittal astigmatic segment X _s not more than - 0.438 mm

- distortion no more than 0.00014%

In the proposed utility model:

| R ₁ | = | R ₂ | = 493.563;

1.3 <n ₁ = 1.489118 <1.68

1.5 <n ₂ = 1.652188 <1.66

where R ₁ and R ₂ are the radii of the first and second optical surfaces along the rays;

n ₁ and n ₂ are the refractive indices of the material of the first and second lenses along the rays for line e.

The ratio of the first along the rays of the radius of the meniscus lens to its second radius is 0.1286.

Thus, as a result of the proposed solution, a technical result is obtained: a two-lens lens with increased focal length and entrance pupil diameter with increased adaptability with high image quality is created.

Claims (3)

1. A two-lens lens consisting of biconvex lenses located along the path and a negative meniscus convex to the image, the radii of the biconvex lens being equal in absolute value, and the ratio of the first meniscus lens radius to the second radius less than 0.8, differing the fact that there are relations: 1.3 <n ₁ <1.68; 1.5 <n ₂ <1.66; where n ₁ and n ₂ are the refractive indices of the material of the first and second lenses along the rays for line e. 2. A two-lens lens according to claim 1, characterized in that the lenses are single. 3. A two-lens lens according to claim 2, characterized in that the lenses are glued.

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