SU1327039A1 - Varifocal lens - Google Patents

Abstract

The invention relates to an optical instrument and enables to improve image quality while reducing the minimum shooting distance. The lens contains four components, of which 1 and 4 are positive fixed, and 2 and 3 are negative, mounted for movement along the optical axis. In the four-lens component 1, the lens 5 is double-concave, and the lens 6 is glued together from positive and negative meniscuses facing inward towards the object. The lens 12 of the fourth component is a positive meniscus with a concavity facing the object. The coefficient of dispersion of lens materials 5, 6, and 12 is connected by a sequence of 0.4: 0.9: 0.4:: 0.1. The aperture diaphragm is located between the two-convex lens 13 and the negative meniscus 14. The relative aperture of the lens, equal to 1: 1.8, remains almost unchanged throughout the entire range of the focal distance. The lens at the location of the object in front of him at a distance of 0.02 m has a macro mode. 1 il. i i (L 5 6 7 8 / / / 7 //; j, 74 vU 75 761778 1Q u i with CD J

Description

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

The aim of the invention is to improve the image quality while reducing the research institute minimum shooting distance.

The drawing shows a principal scheme of a lens with a variable focal length.

The lens consists of four components 1,2,3,4, of which 1 and 4.- Positive fixed, and 2 and 3 negative, mounted for movement along the optical axis. The first component 1 consists of four lenses. The first lens 5 is double-bent, the second 6 “is a two-glued positive meniscus of positive and negative menisci, the third 7 is a two-fold convex, and the fourth 8 is positive meniscus. To refocus over the final distance, the entire first component is moved along the optical axis towards the object. The second component 2 consists of a negative meniscus 9 and. a three-glued lens 10 from two web-like meniscuses and a double-curved lens between them, jointly moving along the optical axis. The third component 3 consists of a two-glued negative lens 11 of biconcave and two convex lenses, which is movable along the optical axis to provide 10-fold. range of focal lengths and additional movement to ensure macro mode. The fourth component 4 consists of a positive meniscus 12, a double-convex lens 13, a negative meniscus 14, a positive meniscus 15, a double-curved lens 16, a double convex lens 17, a positive meniscus 18 and a positive double-glued lens 19 made of two double-convex and double-curved lenses Between the lenses 13 and 14 aperture diaphragm is placed.

The proposed lens has a relative aperture of 1: 1.8, which remains almost unchanged throughout the entire range of focal lengths (13.78-137.5 mm). The minimum shooting distance is 0.8 m. The lens has a macro mode at ras13270392

the position of the object at 0.02 m in front of the lens ..

Lens dimensions: length 250 mm, maximum light diameter 95 mm; weight 3 kg The quality of the image of the lens meets the requirements of modern television lenses, and can be applied -10 in both studio and reportage cameras.

At a focal length of 13.8 mm, the lens has the following image quality characteristics: the transverse-15 river spherical aberration for the main line e is not more than 0.014 mm; spherochromatism in the spectral range -470-620 nm is not more than 0.188 mm; for the sake of vision, astigmatism is not greater than 20 - 0.657 mm; relative distortion is 4.37%; magnification chromaticity not more than 0.008 mm; aberration of a wide oblique beam for an angle at the fundamental wavelength of not more than 0.1 mm.

25 At a focal length of 137.5 mm, transverse spherical aberration is not. more than 0.002 mm; spherochromatism not more than 0.345 mm; for the angle of vision, astigmatism, no more than; 0.376

30 relative distortion no more

0.82%; chromium atism increase no more than 0,030 mts; aberration of a wide oblique beam for an angle of 2 ° 34 not more than 0.061 mm.

2g Formula of invention

A variable focal length object containing four components, of which the first positive immobile contains a negative lens, a positive lens, a two-convex lens and a positive meniscus facing the object, the second negative movement of the components

45 consists of a negative meniscus convex to the object, and a negative lens glued together from two positive menisci and a double-curved lens between them, the third, from-. The gQ retinal movable component consists of glued to each other bifold-curved and double convex lenses, the fourth positive fixed component contains a positive lens,

gg double-convex lens, aperture diaphragm, negative and positive menisci convex to each other, double-bent lens, two-convex lens, positive

concavity meniscus to

subject, and a positive lens, glued together from two-convex and two-curved lenses, characterized in that, in order to improve image quality while reducing the minimum shooting distance, in the first component, the negative lens is made

double-concave, positive - in the vi-jg lens of the fourth component relate to a meniscus reversed in concavity with between itself in the sequence to the object and glued from positiv 0.4: 0.9: 0.4: 1.0.

7039.

in the fourth component, the first positive lens is made in the form of a meniscus with a concavity facing the object, while the dispersion coefficients of materials, respectively, are double-concave and glued lenses of the first component and the first positive

Claims (1)

Claim A zoom lens containing four components, of which the first positive fixed contains a negative lens, a positive lens, a biconvex lens, and a positive meniscus facing the subject, and a second negative movable component. consists of a negative meniscus convex to the object and a negative lens glued from two positive menisci and a biconcave lens between them, the third, negative movable component. of the biconcave and biconvex lenses glued together, the fourth positive 'fixed component contains a positive lens, a biconvex lens, an aperture diaphragm, negative and positive menisci, convex to each other, a biconcave lens, a biconvex lens, positive ³ 1327039. ⁴ meniscus facing concavity to the body and negative menisci, an object, and a positive lens glued from a biconvex and biconcave lenses, characterized in that, in order to improve image quality while reducing the minimum shooting distance, in the first component, the negative lens is biconcave, positive - in bh-, q de meniscus facing concavity to the object and glued from the position in the fourth component, the first positive lens is made in the form of a meniscus facing concavity to the object, while the dispersion coefficients of the materials, respectively, of the biconcave and bonded lenses of the first component and the first positive lens of the fourth component are related to each other in the sequence 0.4: 0.9: 0.4: 1.0.