RU2239211C2 - Objective (variants) - Google Patents

Abstract

FIELD: optics.

SUBSTANCE: in first variant, device consists of two components serially placed along path of beams. First component is two-lens, glued together from flat-convex lens directed by plane to subject, and negative meniscus directed by convex portion to image. Second component is a single biconvex lens. In second variant second component is a single positive meniscus directed by concave portion to image. For radiuses of optical surfaces and refraction coefficients certain relations are true, which are presented in inventive formula.

EFFECT: higher angular field of vision and increased relative aperture with high image quality.

2 cl, 2 dwg

Description

The group of inventions relates to optical instrumentation and can be used in various visual and infrared optical systems.

Known microscope objective [1]. It consists in the direction of the rays from a frontal lens glued from a plano-convex lens, the plane facing the subject and the negative meniscus convex to the image and the lens part following the front lens. This lens is too complex in design (8 lenses). It works from a short distance and has poor image quality when working from infinity, because is a microscope lens.

The closest analogue to the claimed technical solutions is a lens [2], containing two components, the first of which (along the rays) is a two-lens glued from a plano-convex lens facing the object with a plane and a negative meniscus convex to the image, the second is a single plano-convex lens, Plane facing the image; It has insufficient image quality.

In the lens there are equalities:

R ₂ / R ₃ = 0.177

R ₄ / R ₅ = 0

n ₁ = 1.57486

n ₂ = 1.652188

n ₃ = 1.57486

where R ₂ is the radius of the second optical surface along the rays;

R ₃ is the radius of the third optical surface along the rays;

R ₄ is the radius of the fourth optical surface along the rays;

R ₅ is the radius of the fifth optical surface along the rays;

n ₁ is the refractive index of the material of the first lens;

n ₂ is the refractive index of the material of the second lens;

n ₃ is the refractive index of the material of the third lens.

The task of the claimed group of inventions is the creation of lenses with an increased field of view and an increased relative aperture with high image quality.

The technical result is an increase in the angular field of view, an increase in the relative aperture with high image quality.

This is achieved by the fact that in the lens according to the first embodiment, containing two components, the first of which along the rays is a two-lens glued from a plano-convex lens, the plane facing the subject and the negative meniscus convex to the image, the second component is a single positive lens; in contrast to the known one, the positive lens in the second component is biconvex and, in addition, the following relations hold:

0.18 <R _2.1 / R _3.1 <0.3

0.3 <R _4.1 / R _5.1 <0.5

where R _2,1 is the radius of the second optical surface along the rays;

R _3.1 is the radius of the third optical surface along the rays;

R _4.1 is the radius of the fourth optical surface along the rays;

R _5.1 is the radius of the fifth optical surface along the rays.

In the lens according to the second embodiment, containing two components, the first of which along the rays is a two-lens glued from a plano-convex lens, the plane facing the subject and the negative meniscus convex to the image, the second component is a single positive lens; in contrast to the known one, the positive lens in the second component is made in the form of a meniscus facing concavity to the image and, in addition, there are relations:

0.3 <R _2.2 / R _3.2 <0.5

0.1 <R _4.2 / R _5.2 <0.3

1.6 <n ₁ <1.62

1.7 <n ₂ <1.74

1.6 <n ₄ <1.62

where R _2,2 is the radius of the second optical surface along the rays;

R _3,2 is the radius of the third optical surface along the rays;

R _4,2 is the radius of the fourth optical surface along the rays;

R _5,2 is the radius of the fifth optical surface along the rays;

n ₁ is the refractive index of the material of the first lens;

n ₂ is the refractive index of the material of the second lens;

n ₄ is the refractive index of the material of the third lens.

Figure 1 presents the optical diagram of the proposed lens according to the first embodiment, figure 2 - according to the second embodiment.

The lens according to the first and second options (Figs. 1 and 2) consists of two components sequentially located along the rays from the object, the first of which is a two-lens one glued from a plano-convex lens 1 facing the object and a negative meniscus 2 convex to image; the second component in the first embodiment (FIG. 1) is a single biconvex lens 3, in the second embodiment (FIG. 2) is a single positive meniscus 4 facing a concavity to the image.

The entrance pupil in the first embodiment coincides with the first surface; in the second embodiment, it is spaced 90 mm in front of the first optical surface.

The proposed optical system according to the first embodiment works as a lens collecting from infinity, that is, the light flux from an object located at infinity enters the lens, where it passes through lenses 1, 2, 3 and forms an image of the object in the plane of the best setup in which the receiver is installed optical radiation (not shown).

According to the second embodiment, the proposed optical system works in the same way as a lens collecting from infinity, that is, the light flux from an object located at infinity enters the lens, where it passes through lenses 1, 2, 4 and forms an image of the object in the plane of the best installation, in which has an optical radiation receiver (not shown).

In accordance with the proposed solution, lenses were calculated for both options, corrected in the spectral range from 486 nm to 656 nm.

The design parameters of the lens according to the first embodiment are shown in table 1.

Characteristics of the calculated lens:

focal length f ’37.36 mm

relative aperture 1: 2,8

field of view angle of 14 degrees.

The relations are satisfied:

R _2.1 / R _3.1 = 0.194

R _4.1 / | R _5.1 | = 0.448

The design parameters of the lens according to the second embodiment are shown in table 2.

Characteristics of the calculated lens:

focal length 94.7 mm

relative aperture 1: 3,5

field of view angle of 15 degrees.

The relations are satisfied:

R _2.2 / R _3.2 = 0.376

R _4.2 / R _5.2 = 0.175

n ₁ = 1.615506

n ₂ = 1.723166

n ₄ = 1,615506

Table 3 shows the aberrations for λ = 546 nm of the calculated lens options in comparison with the closest analogue.

Thus, as a result of the proposed solution, a technical result is obtained: lenses with an increased field of view, with an increased relative aperture with high image quality are created.

Sources of information

1. A.S. USSR No. 1081610, G 02 B 21/02, publ. 1984 year

2. Certificate for utility model of Russia No. 25353, G 02 B 9/04, 9/06, publ. 2002 year

Claims (2)

1. A lens containing two components, the first of which along the rays is a two-lens one, glued from a plano-convex lens facing the subject with a plane and a negative meniscus convex to the image, the second component is a single positive lens, characterized in that the positive lens the second component is biconvex and, in addition, the relations 0.18 <R _2.1 / R _3.1 <0.3; 0.3 <R _4.1 / | R _5.1 | <0.5; where R _{2,1 is the} radius of the second optical surface along the rays; R _3.1 is the radius of the third optical surface along the rays; R _4.1 is the radius of the fourth optical surface along the rays; R _5.1 is the radius of the fifth optical surface along the rays. 2. A lens containing two components, the first of which along the rays is a two-lens one, glued from a plano-convex lens facing the object with a plane and a negative meniscus convex to the image, the second component is a single positive lens, characterized in that the positive lens the second component is made in the form of a meniscus, facing concavity to the image, and, in addition, there are relations 0.3 <R _2.2 / R _3.2 <0.5; 0.1 <R _4.2 / R _5.2 <0.3; 1.6 <n ₁ <1.62; 1.7 <n ₂ <1.74; 1.6 <n ₄ <1.62, where R _2,2 is the radius of the second optical surface along the rays; R _3,2 is the radius of the third optical surface along the rays; R _4,2 is the radius of the fourth optical surface along the rays; R _5,2 is the radius of the fifth optical surface along the rays; n ₁ is the refractive index of the material of the first lens; n ₂ is the refractive index of the material of the second lens; n ₄ is the refractive index of the material of the third lens.

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