RU2239212C2 - Objective - Google Patents

Abstract

FIELD: optics.

SUBSTANCE: device has three serially placed components along beams route, first of which is two-lens, glued together of biconvex lens and plane-concave lens, directed by plane to image. Second component is single positive meniscus directed by convex portion to object. Radiuses of optical surfaces are interconnected by relations shown in invention formula.

EFFECT: higher adaptability to manufacture and higher image quality.

1 dwg

Description

The present invention relates to optical instrumentation and can be used in various optical systems, for example, in visual, infrared systems, in film and photo lenses.

Known lens [1]. It consists of four lenses along the rays, the first of which is biconvex, the second is the negative meniscus convex to the object, the third lens is positive, the fourth lens is convex, the plane faces the image. The lens has a low field of view 2W = 4 degrees. 52 minutes

The closest analogue to the claimed technical solution is the Tair-11 lens [2], which contains three components, the first of which (along the rays) is a two-lens bonded from a biconvex and biconcave lens, the second and third components are single positive and negative menisci, convex to the object, the third component is the negative meniscus convex to the object.

The lens has a relative aperture of 1: 2.8 and a focal length of 133 mm. Its disadvantage is the low image quality with a relative aperture of 1: 2.8 and a field of view of 2W = 14 degrees. and low manufacturability, as all the radii of the optical surfaces are different, which requires the use of different test glasses and its own processing tool on each optical surface.

The lens has aberrations for λ = 546 nm:

transverse spherical aberration for a point on the axis 0.036 mm;

transverse aberration of a wide inclined beam in the meridional section for the field

view 2W = 14 deg. 0.051 mm;

transverse aberration of a wide inclined beam in the sagittal section for the field of view 2W = 14 deg. 0.028 mm;

meridional astigmatic segment X _m -0.474 mm;

sagittal astigmatic segment X _s -0.296 mm;

distortion of 1.6%.

The following equalities hold:

where R ₁ is the radius of the first optical surface along the rays;

R ₂ is the radius of the second 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.

The task of the invention is to create a lens with improved image quality and increase manufacturability.

The technical result is an increase in the image quality of the lens with a relative aperture of 1: 2.8 and a field of view of 2W = 14 deg.

This is achieved by the fact that in a lens containing three components, the first of which along the rays is a two-lens glued from a biconvex and negative lenses, the second component is the positive meniscus, convex to the object, the third component is the negative meniscus, convex to the object, the difference from the known negative lens in the first component is made in the form of a flat-concave lens, facing with the plane to the image, and, in addition, there are relations:

where R ₁ is the radius of the first optical surface along the rays;

R ₂ is the radius of the second 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;

The proposed lens has a high technology, because the radii of the two optical surfaces are equal and, therefore, when processing the surfaces they need the same test glasses and a processing tool, and, in addition, one optical surface is flat, and on a flat surface there are always test glasses and a processing tool.

The drawing shows an optical diagram of the proposed lens.

The lens consists of three components sequentially located along the rays from the subject, the first of which is a two-lens, glued from a biconvex lens 1, and a plano-concave lens 2, the plane facing the image; the second component is a single positive meniscus 3, convex to the object, the third component is the negative meniscus 4, convex to the object.

The entrance pupil is 12.08 mm apart after the first optical surface.

The proposed optical system works like a lens collecting from infinity: the light flux from an object enters the lens, where it passes through lenses 1, 2, 3, 4 and forms an image of the object in the plane of the best setup in which the optical radiation receiver (not shown) is located.

In accordance with the proposed solution, a lens is calculated that is corrected in the spectral range from 486 to 656 nm.

The design parameters of the lens are shown in table 1.

Characteristics of the calculated lens:

focal length 70 mm;

relative aperture 1: 2.8;

field of view angle of 14 degrees.

Table 2 shows the aberrations for λ = 546 nm of the calculated lens in comparison with the closest analogue.

The relations are satisfied:

Thus, as a result of the proposed solution, a technical result is obtained: a lens with a field of view of 2W = 14 deg., With a relative aperture of 1: 2.8, with improved image quality is created.

Sources of information

1. Japan patent No. 60-49287, G 02 In 13/00, publ. 1979 year

2. The lens "Tair-11", the optical release of the State Optical Institute, publ. 1957

Claims (1)

A lens containing three components, the first of which is a two-lens lens glued from biconvex and negative lenses, the second and third components are positive and negative menisci convex to the object, characterized in that the negative lens in the first component is made in the form of a flat-concave lenses, the plane facing the image, and there are relations | R ₂ | = R ₄ ; 0.9 <R ₁ / | R ₂ | <1.8; 0.45 <R ₄ / R ₅ <0.6, where R ₁ is the radius of the first optical surface along the rays; R ₂ is the radius of the second 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.