SU1383271A1 - Catadioptric lens of telescope - Google Patents

Abstract

FIELD: optical instrumentation; used in binoculars. The purpose of the invention is to improve the image quality and reduce the length of the lens. The lens aberration compensator is glued from a flat-bent lens 2, a positive meniscus 3 and a two-convex lens 4, on the peripheral part of which a primary mirror 5 is applied. A parallel beam of rays reflected from mirror 5 is directed by a flat mirror 6 to the positive meniscus 7 glued to the central part convex surface of the compensator. The secondary mirror 8 is applied to the peripheral part of the convex surface of the meniscus 7. A real direct image of the object is obtained in the rear focal plane of the lens. Lens 2 and meniscus 3 are made of a material with refractive indices that differ by no more than 0.0.5. The refractive index of lenses 4 and meniscus 3 differ by more than 0.1. Coefficient dispersion of meniscus 3 is less than the coefficient. dispersion of a lens 2 on four and is equal to kozf. lens dispersion 4. 1 Il. with

Description

 pupil

00 os so yu

The invention relates to optical instrument making, namely to mirror-lens lenses of telescopes, and can be applied in binoculars.

The purpose of the invention is to improve the image quality and reduce the length.

The drawing shows the principal optical scheme of a mirror-lens lens.

The lens contains a flat-convex lens 1, glued together from a flat-concave lens 2, a positive meniscus 3 and a two-convex lens 4. A reflective coating is applied on the convex surface of lens 1, which is the primary mirror 5, and a flat mirror 6 is applied on the central area of the first flat surface of lens 1 In the center of the convex surface of the flat convex lens 1, a positive meniscus 7j is glued onto the convex surface of which a secondary mirror is applied 8

The lens works as follows.

A parallel beam of rays passes through the flat-bell-shaped lens 1 and falls on the primary mirror 5, reflecting from it passes again through the lens 1 glued from the lenses 2-A, and falls on the flat mirror 6, reflected from which the lens 1 passes, meniscus 7 and falls on the secondary mirror 8, while in the lens 1 there is a real intermediate image of an infinitely distant object. Further, the beam is reflected from the mirror. 8, the lenses 7 and 15 again pass through again onto the flat mirror 6. Having reflected from the mirror 6, the beam successively passes the lenses 2,3,4 and 7 and in the back focal plane of the whole lens a real direct image of the object is obtained, Example. The calculation for the mirror-lens lens telescope with the following characteristics:

Focal distance

mm

Input diameter

pupil, mm

Angle floor, hail

Lens length along

optical axis, mm

In the given example, the calculation of the mirror-lens lens spherical foE 202

D8x., P 52 2w 3

L 49,46

0

five

ka aberration when using the installation plane a 0.55 mm. Accordingly, for the four points on the pupil is equal to: 0.032; -0.026; –0.078 and 0.080 mm — double correction of spherical aberration was made.

The chromatism of the position of the lens does not exceed 0.28 MMj in the pupil and the chromatism of the increase along the edge of the field is -0.042, in the zone - 0.028 mm.

Curvature of the image across the field in the lens, mm: at the edge Z -0.096,

Zg 0.35; at Z -0.042, (u

ZL 0.16.

0

five

0

five

0

five

0

five

spherical aberration in the meridional section does not exceed 0.12 mm. Distortion: on the edge - 0,22, on the zone - 0,098%.

Claims (1)

Invention Formula Mirror-lens lens of the telescope containing concave primary and secondary mirrors and an aberration compensator located between them in the form of a convex lens, glued from three lenses, the first of which is flat-concave, the second and third are positive, and the primary mirror is applied to the peripheral part of the convex surface of the compensator aberrations, characterized in that, for the purpose of improvement, image quality and reduction in length, since the central part of the convex surface of the compensator of the portable radios is glued meniscus, a secondary mirror is applied to the peripheral part of the upper surface of the secondary mirror, a flat mirror is applied to the central part of the front surface of the aberration compensator, the second lens is made in the form of the meniscus in the compensator of aberrations, and two lenses differ by no more than 0.05, the dispersion coefficient of the first lens is greater, the dispersion coefficient of the second lens is not less than 4, the refractive index of the third lens differs from n the refractive index of the second lens is more than 0.1, and the coefficient of dispersion of the third lens is equal to the coefficient of dispersion of the second lens.