SU1296986A1 - Zoom lens - Google Patents

Abstract

This invention relates to the field of optical instrumentation. The aim of the invention is to improve the image quality and reduce the length of the lens. A lens with a variable focal length contains five components, the first, fourth and fifth of which are fixed, and the second and third are installed with the possibility of movement along the optical axis. The focal length of the first four components lies within 0.8-1.2 of the focal length of the entire lens, and the distance between the fourth and fifth components is at least 0.1 times the maximum focal length, which made it possible to achieve a correction. astigmatism to 0.17 mm; image curvature to 0.08 mm; and lens reduction to 208 mm. 1 silt, from 1C (L y from 05 from 00 and

Description

t-1

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

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

The drawing shows the principal optical scheme of a lens with a variable focal length,

A lens with a variable focal length contains five components. Components 1, 4, and 5 are positive fixed, components -2 and 3 are installed with the possibility of moving along the axis, while component 2 is negative and component 3 is positive.

Component 1 consists of glued between two double-convex 6 and double-concave 7 lenses and a positive meniscus 8, convex to the object. Component 2 includes a negative meniscus 9, convex to the object, and a negative lens glued together from a double-curved lens 10 and a positive meniscus 11. Component 3 consists of a Dual-convex lens 12, glued together by a double-curved 13 and two-convex 14 lenses. AND

positive meniscus 15, convex to the subject. Component 4 is made of double-concave and double-convex 17 lenses, component 5 is made of a negative meniscus 18 facing the concavity of the image, and two-convex lenses 19.

In this scheme, the lens is designed with a focal length varying from 15 to 150 mm. The relative aperture of the lens is 1: 2.8, the linear field is about 11.5 mm. The length of the lens is 208 mm, which is 1.38 with respect to the maximum focal length,

The lens corrected dp dpiny wavelength 0.766 μm, achromatized for the spectral region from 0.60 μm to OO, 90 μk

By choosing a focal length

The body meniscus is made of glass with a refractive index of more than 1.74 and a dispersion coefficient of more than 50, the double-curved lens is made of glass with a refractive index of more than 1.8 and a dispersion coefficient of not more than 27, characterized in that in order to improve the image quality and reduction of length, in the fourth component after the four lens components in the range of 0.8-1.2 maximum focus; 5, the concave lens is set to the double distance of the entire lens and the lens lens, the focal distance by selecting the distance between the fourth. the first four components are selected and fifth components, greater than 0.1 in the range of 0.8-1.2 maximum focal length of the lens, and correction of the curvature of the image to 0.08 mm, astigmatism to 0.17 -mm and reducing the length of the lens to 208 mm. The design of the fourth component provided a high degree of correction for the spherical aberration of coma (up to 0.04 mm) and chromatic aberrations. As a result, the contrast transfer ratio of 30 l / mm for the proposed lens for a center field is not lower than 0.6, and dp field size , 4 is not lower than 0.5.

Because of this, the lens can be used in high definition television systems.

Claims (1)

Invention Formula five five A lens with a variable focal length containing five components, of which the first, fourth and fifth positive components are fixed, and the second negative and third positive are mounted for movement along the optical axis, the first component containing a positive lens glued together from a two-fold and two co-curved lenses, and a positive meniscus, 30 which is convex to the object, the second is a negative meniscus, which is convex to the object, and a negative lens glued together from a two-bent lens and a positive one. 35 meniscus, third - double-convex a lens, a positive lens glued together from a double-bent and double-convex Liis, and a positive meniscus convex to the object, the even lens is a double-bent lens, n -. This is a negative meniscus reversed to the object and a double convex lens; in the first component of the double convex lens and a positive meniscus are made of glass with a refractive index of more than 1.74 and a dispersion coefficient of more than 50; the double bent lens is made of glass with a refractive index more than 1.8 and a dispersion coefficient of not more than 27, characterized in that, in order to increase the image quality and reduce the length, in the fourth component after two  a concave lens is fitted with a double-convex lens; the focal length of the first four components is selected within 0.8–1.2 of the maximum focal length of the lens, and The position between the fourth and fifth com- ponent focal lengths is at least 0.1 lens. Have Editor A, Revin Compiled V. Arkhipov Tehred M. Khodanych Proofreader A, Zimokosov Order 776/49 Circulation 522Subscription VNIIPI State Committee for GSS for inventions and discoveries. 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and printing company, Uzhgorod, st. Project, 4