SU1649493A1 - Compact objective lens - Google Patents

Abstract

The invention relates to optical instrumentation and can be used to produce high-quality images. The purpose of the invention is to increase the relative aperture. In the object, 1,3,5,8 - negative menisci, 2,4,7 - double convex lenses, 9 - double lens concave. Focal distance 24 mm, relative aperture 1: 1, field angle of view 40 °. 1 hp f-ly, 1 ill.

Description

1 2 S i 10 4. Plane

h / / / 7 5.

This invention relates to an optical instrument, namely, high-aperture and wide-angle lenses.

The aim of the invention is to increase the relative aperture.

The drawing shows the principal optical layout of the lens.

The lens contains a negative meniscus 1, facing the concavity to the image space and made of glass with a refractive index of not more than 1.62 and a coefficient of average dispersion less than 35J, a convex lens 2 with a focal length of 1.68f, a negative meniscus 3 facing the concavity to space objects and made of glass with a refractive index of more than 1.75 and a coefficient of average dispersion

less than 28; a single double-convex lens 4 with a focal length of 1.52f, a negative meniscus 5 with a focal distance of 25f facing the image space and, made of glass with a refractive index of not more than 1.62 and an average dispersion coefficient of more than 60J two a co-convex lens 6 with a focal length of 1,188f glued together from a two-convex lens 7 and a negative, meniscus 8 facing inward towards the space of objects and made of glass with a refractive index of not more than 1.62 and an average dispersion coefficient of more than 60} a double-curved lens 9 with a focal length of 0.77f, made of glass with a refractive index of more than 1.75 and an average dispersion coefficient of less than 30 (f1 is the focal distance of the objective). After the third component 3, the aperture diaphragm 10 is located.

Small lens OPALAR

50

CB-1 is a photographic object, especially the increase chromatism,

Meniscus 1 is made of glass with a refractive index of not more than 1.62 and an average dispersion coefficient less than 35, and Meniscus 2 is made of glass with a refractive index of more than 1.75 and a coefficient of average dispersion less than 28. To correct spherical aberration of wide oblique beams between negative menisci 1 and 3 are installed two co-convex lens 2.

In the proposed embodiment, the spherical aberration AS for a point on the axis does not exceed 0.07 mm in a wide range from (0.4 µm to 2

It is intended for observing distant objects, therefore a parallel beam of rays is incident on the lens.

The rays pass through the first three components 1, 2 and 3, completely fill the aperture diaphragm 10, which determines the luminosity of the system, then pass successively through the lenses 4-9, and in the focal plane of the lens create a real image of the infinitely distant object.

As an example of a specific embodiment, a small-sized

55

five

4934

lens OPALLR-SV-11 characteristics: Focal distance f

with the following

25 mm

Relative hole D: f

1: 1

0

Angle field of view 2CO40 °

Rear focal length S 2.95 mm Lens length About 46.4 mm Resolution in the center of the floor 80 l / mm, on the edge - 40 l / m.

The proposed lens is highly luminous, therefore, to increase the relative aperture behind the aperture diaphragm 10 a single two-cap convex lens 4 and two co-convex lens 6 glued from the two convex lens 7 and negative meniscus 8, facing in the space of objects, is placed.

To correct the chromatism of the position, the curvature of the image and the astigmatism in the lens, a negative meniscus 5 is placed in front of the glued lens 6, its concavity facing the image space.

To increase the rear focal length and to correct the curvature of the image and astigmatism, a double-curved lens 9 is placed in front of the image plane.

The magnitudes of the focal lengths of the individual components are chosen experimentally and make it possible to obtain a lens of small dimensions. The length of the lens along the axis is 46 mm.

Two negative menisci 1 and 3 are turned with a concavity to the space of objects to increase the angular field of the lens.

To correct chromatic aber 0,9 microns. The main wavelength is fl0 0.65 µm. For the main wavelength, the longitudinal spherical aberration does not exceed 0.05 mm, the transverse - 0.03 mm at the edge of the pupil, and at the zone these values are respectively 0.0085 and 0.0032 mm.

The chromatism of the position does not exceed 0.14 mm. The chromatism of magnification does not exceed 0.02 mm. The image curvature is equal to Zx for the field of view Zx 0.054 mm, tg -0.111 mm.

At a focal length of the lens of f 24 mm, its length along the optical axis is 46.4 mm. The back focal section is 2.95 mm.

Claims (2)

1. A small-sized lens containing seven lenses and an aperture diaphragm, the first lens being a negative meniscus, a third a meniscus, a fourth and a pole positive, a pt negative, and with, to increase the relative aperture, the first the lens is turned with a concavity to the object, the second and fourth are made double-convex, a third is made negative and the side is convex to the object; , and the aperture diaphragm is installed between the third and fourth lenses. 2. The lens according to claim 1, from part to point 5, and so that the focal lengths of the lenses from the first to the seventh are 108, 1.68, 1.977, 1.52, 25, 1.188, respectively. 0.77 lens focal length, indicators The refractive index of the material of the first, third, fifth, two-convex lens, lens test and the seventh lens is respectively not more than 1.62, more than 1.75 not more than 1.62, not more than 1.62 and more than 1.75, and the coefficients of the average dispersion of the material of these lenses are respectively less than 35, less than 28, more than 60, more than 69 and less than 30.