SU1522135A1 - Objective with external diaphragm - Google Patents

Abstract

The invention relates to optical instrumentation and can be used in the development of compact lenses for cameras with an electronic diaphragm. The aim of the invention is to improve the image quality by correcting the aberrations of oblique beams and reducing distortion. The lens contains a positive meniscus 1, a glued positive meniscus 2, a double-curved lens 5 and a glued two double convex lens 6. Performing the meniscus 2 with the gluing surface that faces the object and the refractive indices of lens 3 and 4 can reduce the relative distortion and to whom Focal distance 35 mm, relative aperture 1: 2.8, field angle of view 63 °. 3 il.

Description

The invention of optical instruments for optical instrumentation, in particular, for photographic lenses, can be used in devices that require a lens with a transparent diaphragm and high image quality.

The purpose of the invention is to enhance the image quality by correcting the aberration of oblique beams and reducing distortion.

FIG. 1 shows the principal optical layout of the lens; FIG. 2 is a graph of a polychromatic frequency-contrast characteristic (MTF) for a point on the axis (); in fig. 3 - the same for a point on the edge of the field of view (mm).

The lens consists of four components arranged in series along the beam, the first of which is a positive meniscus 1, convexity facing the space of objects; the second is a positive meniscus 2, convexity facing the space of objects, glued together from two lenses 3 and 4, with a surface of facing the space of objects, with the refractive index of lens 3 being larger than the refractive index of lens 4, the third is a negative double-curved lens 5, the fourth is a positive two-convex Lens 6, glued from two lenses 7 and 8, with a gluing surface facing the space of images.

The implementation of the second component 2 of glued from two lenses 3 and 4 with a gluing surface convex to the space of objects, provided that the refractive index of lens 3 is larger than lens 4, provides additional possibilities for correcting the relative distrosis, meridional and sagittal coma inclined beams, and equal

0

c

5 5

0 45

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numbered across the field, which allows the abilities of aberrations of wide oblique beams to improve the image quality, characterized by the MTF.

The obtained lens has the following technical characteristics: focal length of the lens is 35 mm; relative hole 1: 2,8; the angular field in the space of objects 63, the main wavelength of 546 nm; working interval of wavelengths 435- 656 nm.

The aperture diaphragm is located after the last surface of the lens at a distance of 0.9 mm.

The coma size measured by the caustic radius R is 0.38 and 0.92 mm for mm and 0.24 and 0.58 mm for 13 mm.

In the specific example of the lens, it was possible to obtain a double correction of the meridional coma and thereby reduce the magnitude of the aberrations of the inclined beams.

The relative distortion does not exceed 0.7%,

Claims (1)

Invention Formula A lens with a lens diaphragm containing four components, of which the first and second are positive menisci facing the object, the third is a double-bent lens, the fourth is a double lens, the glued lens has a gluing surface that is convex to the image, characterized in that the purpose of increasing the image quality due to the correction of the aberrations of oblique beams and reducing distortion, the second component is made of glued, of two lenses, the index of the first of which exceeds the index tim second and gluing vtuklostyu surface facing to the object. III Yu 20 30 40 50 shnIp Thebes. Z W 0.6 QM 0,