SU617760A1

SU617760A1 - Six-component objective lens

Info

Publication number: SU617760A1
Application number: SU742042109A
Authority: SU
Inventors: Дитцш Эберхард; Эберич Герхард; Риш Герхард
Original assignee: Eberkhard Dittssh; Gerkhard Eberich; Gerkhard Rish
Priority date: 1973-07-09
Filing date: 1974-07-08
Publication date: 1978-07-30
Also published as: DD107348A1; DE2420611A1; HU167696B; FR2237211B1; CS176549B1; FR2237211A1; NL7409092A

Description

: I: I

Изобретение относитс к шестиэлементным объективам с высокой светосилой минимум 1 : 0,75 и полем изображени минимум 0,6/ (/ - общее фокусное рассто ние объектива).This invention relates to six-element lenses with a high aperture ratio of at least 1: 0.75 and an image field of at least 0.6 / (/ is the total focal length of the lens).

Примен емый преимзщественно дл рентгенографии и осциллографии объектив известной конструкции состоит из двух фокусирующих линз, рассеивающего элемента, у которого поверхность, повернута к объактиву , вогнута , а радиусы двух наружных , граничащих с воздухом, поверхностей по величине больше /, из дву ковыпуклой фокусирующей линзы, а также из двзх других элементов, из которых последний представл ет собой предназначенную дл выравнивани лол изображени плосковогнутую линзу Смита, плоска поверхность которой повернута к изображению.Used primarily for X-ray and oscillography, the lens of known construction consists of two focusing lenses, a diffusing element whose surface is turned towards an oblique, concave, and the radii of the two outer air-borne surfaces are larger than /, a two-convex focusing lens, as well as of two other elements, of which the latter is a flat-bent Smith lens intended for alignment of the image, the flat surface of which is turned towards the image Yu.

В известных объективах такой или подобной конструкции ,1, 2 удовлетворительное качество изображени может быть достигнуто при светосиле до 1 : 0,85, однако при больщих пол х изображени (0,6/) зональные отклонени искривлени пол изобретени или край этого пол сильно перекорректированы по отношению к искривлению . Ввиду нарушающего вли ни искривлени Пол изображени у таких объективов повышение светосилы, требуемое , например, дл рентгеновских снимков изображени на экране с целью сокращени времени экспозиции, всегда ведет к потере разрешающей способности.In known lenses of this or similar design, 1, 2, satisfactory image quality can be achieved with aperture ratio up to 1: 0.85, however, with large fields (0.6 /), the zonal deviations of the curvature of the field of the invention or the edge of this field are greatly corrected by to curvature. Due to the disturbing effect of the Polarization of the image in such lenses, the increase in luminosity required, for example, for X-ray images on the screen in order to reduce the exposure time, always leads to a loss of resolution.

Кроме того, известные объективы имеют минимум два элемента, производство которых, в частности с большими фокусными рассто ни ми, св зано с технологическими трудност ми.In addition, known lenses have at least two elements, the production of which, in particular with large focal lengths, is associated with technological difficulties.

Цель изобретени - увеличение светосилы объектива минимум до 1 : 0,75 и пол изображени до 0,6f. Нар ду с этим такой объектив должен иметь минимальное число линз |И элементов.The purpose of the invention is to increase the aperture ratio of the lens to at least 1: 0.75 and the image floor to 0.6f. Along with this, such a lens should have a minimum number of lenses | And elements.

Согласно изобретению значительное выравнивание пол изображени достигнуто за счет того, что линза Смита выполнена из стекла с показателем преломлени , большим 1,70, в результате чего повысилась оптическа сила линзы и в конечном результате увеличилс радиус вогнутой поверхности этой плоско-вогнутой линзы и з меньшилось крайне сильно перекоррегированное действие у больших полей изображени .According to the invention, a significant alignment of the image field is achieved due to the fact that the Smith lens is made of glass with a refractive index greater than 1.70, as a result of which the optical power of the lens increased and, as a result, the radius of the concave surface of this flat-concave lens increased and very low strongly re-corrected action on large image fields.

Claims

The component mounted in front of the Smith lens is made in the form of a single meniscus with a concavity facing the image, with a thickness of (0.38–0.60) / and a focal length of less than 5 /, and the first and second components are made in the form of a two-convex lysis and 1 name respectively, with a focal distance longer than when a Smith lens was installed, the deflection arrow P at the concave surface of the lyse and the optical path W with increasing deflection at this surface change by the value W jP. l If P is raised to a power and additionally adds force to the refractive index, we get JL.h + ± - + m1 + Wl 2 L 4 + i (r + -iSo, the expansion terms in Fourier series are in brackets , cause a significant overcompensation of the distortion of the image field with a large image height h, compared to this, natural parabolic distortion of the image field does not have these degrees. Consequently, for economic reasons, the aspherical lens is not taken into account, but the influence of the components with a large value h is reduced. P occurs here as a result of a high refractive index of the lens; in this case, the concave radius r of the lens increases in a ratio n - 1 g, for example, when going from a lens with a-refraction index, 5 to lens c, 7 by 1.235. As a result of this, the influence of a quadratic element of a power series decreases by 35%, and the influence of higher elements is even greater. As a result of a small re-corrected lens effect on the aperture deflection of the focusing curve, the coma and the contrast increase image quality. With such a lens, the dispersion does not play a role, but the usual heavy optical glasses are taken into account. In exactly the same way as the mentioned lens, the image overcompensating effect on the curvature of the field has scattering surfaces that are convex to the image in the lens elements near the Smith lens. In the proposed lens, a spherical correction with an enlarged opening is provided by a uniform distribution of optical power, with four of the six lens elements having a focusing effect. The component located in front of the Smith lens has a focal distance of less than 5 /, the focusing power of this element is concentrated towards the object. The first two objective lenses have focal lengths in excess of 2f, the first one being double-convex, and the second is made in the form of a positive meniscus, as a result of which, despite the economy of one correction element, the spherical zonal deviation is reduced compared with similar lenses. Constructive embodiments of the lens of the present invention are shown in FIG. 1-3. They are designed for different scales and image fields and characterize the area of structural elements in which correction is possible. The lens consists of six components 1-6, of which components 1 and 2 are made respectively of a two-convex lens and a meniscus with a concavity facing the image. Component 3 is glued from a double-bent lens and meniscus, and components 4, 5, 6 are single-lens and are made accordingly: 4 - in the form of a single two-convex lens with a focal length exceeding /; 5 - in the form of a single meniscus with a concavity facing the image, with a thickness of (0.38-0.60) /; 6 - in the form of a Smith lens from a material with a refractive index exceeding 1.70, facing the flat surface to the image. The invention A six-component lens containing two positive single-lens components, a negative two-lens glued component mounted behind them, the surface of which, bordering on the air and facing the object, is concave, and its size, like the other, that borders on the surface of this component exceeds the focal length f of the entire lens, a single two-convex lens with a focal length exceeding f, and two components, the latter of which is the Smith lens, is flat-faced to image, characterized in that, in order to increase the relative aperture to 1: 0.75 and the image field to 0.6 /, the Smith lens is made of a material with a refractive index exceeding 1.7, the component placed in front of it is a single meniscus with a concavity facing the image, with a thickness of (0.38–0.60) / and a focal distance of less than 5 /, and the first and second components are made in the form of a two-convex lens and meniscus with a focal length greater than 2 / .

Sources of information taken into account in the examination 1. French patent number 214874, cl. G 02B 11/34, 1969.

2. The patent of Germany No. 918393, cl. 42h 42/20, 1944.

3. USSR author's certificate number 333534, cl. G 02B 9/64, 1970.

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