RU2359295C1 - Telescopic galilei-type optical system - Google Patents

Abstract

FIELD: instrument engineering.

SUBSTANCE: telescopic Galilei-type optical system consists of a lens system and an ocular. Lens system consists of two positive lenses, the first one of which is bonded of double convex and concave-shallow lenses, and the second one is double convex. Ocular is a single double concave lens. Dispersion factor for e line of ocular lens material can be more than 40 and less than 95.

EFFECT: increasing visible magnification, increasing diametre of entrance pupil and angle of vision in the area of objects, and improving image quality.

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Description

The present invention relates to optical instrumentation and can be used in optical systems operating with lasers, for example in laser rangefinders.

Known telescopic system of the Galilean type, designed to observe distant objects, consisting of a lens and an eyepiece. (Slyusarev G.G. Calculation of optical systems. - L .: Engineering, 1975, p. 195, Fig. 11.32). The lens is made of sequentially located positive meniscus, convex to the object, and a lens glued from a biconvex and biconcave lenses, and the eyepiece is a single biconcave lens. This system is characterized by a long length and a small increase.

Closest to the claimed technical solution is a telescopic optical system of the Galilean type, containing along the rays of the lens, consisting of two positive lenses, the first of which is glued from a biconvex and biconcave lenses, and the second is a single convex flat lens, as well as an eyepiece in the form of a single biconcave lens (Russian Patent No. 2209455, G02B 23/00, publ. 2003). This optical system provides a visible increase of no more than 5.5 times, has a small entrance pupil diameter of 22.5 mm, a small field angle in the space of objects 2′30 ″ and insufficient image quality (for example, angular spherical aberration for a point on the axis is 11 , 1 arcsec, and the aberration of a wide oblique beam for a field of view of 2 min 30 sec is 27.9 arcsec).

The task of the invention is the creation of a telescopic optical system with enhanced performance and improved image quality.

The technical result is an increase in visible increase, an increase in the diameter of the entrance pupil, an increase in the field angle in the space of objects, and an increase in image quality.

This is achieved by the fact that in a Galilean-type telescopic optical system containing a lens and an eyepiece, in which the lens consists of two positive lenses, the first of which is glued from a biconvex and negative lenses, and the eyepiece is a single biconcave lens, in contrast to the known one, negative the objective lens is concave; the second positive objective lens is biconvex. The condition can be fulfilled in the system: the dispersion coefficient for the line e of the eyepiece lens is more than 40 and less than 95.

The drawing shows an optical diagram of the proposed telescopic system, which contains a lens sequentially arranged along the rays, consisting of two positive lenses: the first is glued from a biconvex 1 and concave plane 2 lenses, the second is a single biconvex lens 3, as well as an eyepiece 4, made in the form of a single biconvex lens.

In accordance with the proposed solution, a telescopic optical system was calculated for a wavelength of 1067 nm, achromatized for a wavelength of 1067 nm and 656 nm. The design parameters of the system are given in table 1.

Characteristics of the calculated telescopic system

Visible increase, krat 7.5 Diameter of entrance pupil, mm 32,5 Diameter of exit pupil, mm 4.3 Field of view 5′20 ′ ′ Removal of the exit pupil, mm 36.6

The dispersion coefficient for the line e of the material of the eyepiece lens - glass STK119 - is in the range from 40 to 95 (50.21).

Table 2 shows the aberrations of the calculated telescopic system for λ = 1067 nm.

The system operates as follows. Lens 1-3 creates an imaginary direct intermediate image of the object near the focal plane of the eyepiece (not shown in the drawing), and eyepiece 4 transfers the image to infinity. The proposed telescopic optical system can also work in the reverse ray path (with a decrease).

Thus, as a result of the proposed solution, a technical result is obtained: a telescopic optical system of the Galilean type was created with a visible magnification of 7.52 times, with an increased entrance pupil diameter of 32.5 mm, with an increased field of view of 2W = 5′20 ″, with an increased image quality.

Table 1 The design parameters of the telescopic optical system Radius mm Thickness mm Glass mark Refractive index n _e Coeff. dispersion ν _e Light diameter mm R ₁ = 221.3 35.3 d ₁ = 4.6 TK102 1,57486 57.2 R ₂ = -96.38 35,2 d ₂ = 3 TF105 1.761712 27.32 R ₃ = ∞ 35.1 d ₃ = 0.5 one R ₄ = 104.47 35 d ₄ = 3.7 TK114 1,615506 60.34 R ₅ = -2148 34.7 d ₅ = 123.87 one R ₆ = -28.71 4.7 d ₆ = 1 CTK119 1,747647 50.21 R ₇ = 28.71 4.6

table 2 Aberrations of the telescopic optical system Type of aberration Aberration value, no more nearest analogue proposed system for λ = 1540 nm for λ = 1067 nm Transverse spherical aberration for a point on the axis 11.1 arcsec 1.2 arcsec Transverse aberration of a wide inclined beam in the meridional section for the field of view 2W = 5′20 ′ ′ 27.9 arcsec 16 arcsec Transverse aberration of a wide inclined beam in a sagittal section for the field of view 2W = 5′20 ′ ′ 11.1 arcsec 0.6 arcsec Meridional astigmatic segment X _m for the field of view 2W = 5′20 ′ ′ 0.0146 diopters 0.0094 diopters Sagittal astigmatic segment X _s for the field of view 2W = 5′20 ′ ′ 0.0141 diopters 0.0032 diopters

Claims (2)

1. A telescopic optical system of the Galilean type, comprising a lens and an eyepiece, in which the lens consists of two positive lenses, the first of which is glued from a biconvex and negative lenses, and the eyepiece is a single biconcave lens, characterized in that the negative lens of the lens is made concave, and the second positive objective lens is biconvex. 2. The telescopic optical system according to claim 1, characterized in that the dispersion coefficient for the line e of the material of the eyepiece lens is more than 40 and less than 95.