SU1506413A1 - Variable-focus objective lens - Google Patents

Abstract

The invention relates to optical instrumentation and can be used in lenses with variable focal length for small-sized television cameras. The purpose of the invention is to improve the image quality in the field of view. The first positive stationary component 1 is made of lenses 5-11, the second negative movable one - from lenses 12-14, the third positive movable one - from lenses 15-17 and the fourth positive motionless - from lenses 18-25. The focal distance is 13-78 mm, the relative aperture is 1: 2.3 - 1.3, the linear field of view is 16 mm. 1 il.

Description

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The invention relates to optical instrumentation, namely to lenses with variable focal length, and can be applied in small-sized television cameras for various purposes and in photographic devices.

The aim of the invention is to improve the image quality in the field of view.

The drawing shows the principal optical layout of the lens.

The lens contains the component's chtfe: first 1 - positive non-sublime, second 2 - negative moving along the axis, third 3 - hygienically moving along the axis, fourth- Tbifi 4 - positive stationary. Component 1 is made of a negative meniscus 5, a double-curved lens 6, a positive meniscus 7, a positive lens glued together from a double-concave 8 and two convex 9 lenses, a double convex lens 10 and a positive meniscus 11. Component 2 contains a distinct meniscus 12 and a negative lens glued from a bovine-curved lens 13 and a positive menis. 14. Component 3 includes a positive lens glued from a negative meniscus 15 and a two-convex

lenses 16, and a positive meniscus 17. Component 4 contains a negative lens glued together from a double-curved lens 18 and a positive meniscus 19, a positive meniscus 20, a double-curved lens 21, a positive lens glued from a two-convex lens 22 and a negative meniscus 23, and a healthy lens, glued together from a double convex lens 24 and a negative meniscus 25.

The drawing also shows the light filter 26 and the protective glass 27 of the transmitting television tube.

The lens has the following characteristics: the focal length varies from 13 to 78 MMJ relative aperture 1: 2.3-1: 3; linear field of view, mm; The length of the lens, including the rear focal length, is 206.2 mm, which is 2.64 with respect to the maximum focal length of the lens.

The choice of optical power and the shape of the lenses 20 and 21 in the fourth component 4 makes it possible to correct the astigmatism in the lens while reducing

3

air gap between them as well

the focal length of the lens is also shortened, thus reducing the length of the lens, including the rear focal length, by 20%. The selection of the relative position and shape of the lenses 22-25 of the fourth component allows correcting the spherical aberration of both the coma and the combination of the lenses 20 and 21 to reduce the curvature of the image, resulting in the mean for two directions the value of the contrast transfer ratio at 24 LIN / MM for the point floor, 4 mm increases to 0.5-0.65 over the entire range of focal lengths.

Claims (1)

Invention Formula The lens with a variable focal length, containing the component's chatef, the first and fourth of which are half-frame stationary, the second is negative, the third is positive, the second and third components are mounted for movement along the optical axis, and the first component contains a negative meniscus, ; A convexity to the object, a double-curved lens, a positive meniscus convex to an object, a positive lens glued from two-concave and two convex lenses, a double convex lens and olozhitelchsh meniscus facing convex to the object, the second component comprises a negative meniscus facing vypykloctyu to the subject, and a negative lens of biconcave glued lenses and po-, a positive meniscus, the third component contains a positive lens glued from a negative meniscus and a two-convex lens, and a positive meniscus convex to an object, a quarter component contains five lenses, the first of which is negative, glued from a double-bent lens and a positive meniscus, a fourth and fifth - positive duals, characterized in that, in order to improve image quality over the visual field, in the fourth component the second lens is designed as a positive meniscus reversed concavity to the image, one third in length 51506413 on a double-concave, and a fourth and a half - double-convex lenses and negative lenses are made of glued together from the mucosal carcass.