DD286239A5 - Weitwinkelokular - Google Patents

Abstract

The wide-angle eyepiece for telescopes with a large field of view comprises successively from the side of the intermediate image to be imaged a negative cemented lens of a biconvex lens and a biconcave lens, a biconvex lens, a positive cemented compound of a biconvex lens and a convex-concave lens, a biconvex lens, whose interim image facing surface is aspheric, and a positive meniscus lens. Fig. 2 {wide angle eyepiece; Telescope; great field of vision; negative trilinear cemented component; biconvex, biconcave; positive cemented component; convex-concave; aspherical; Lens}

Description

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For this 1 page drawings

Field of application of the invention

The invention relates to a wide-angle eyepiece, which can be seese'tf for telescopes with a large field of view, especially for terrestrial applications.

Characteristic of the known state of the art From the patent US4525035 a six-lens eyepiece for a field of view of 80 ° is known, in which the cutting width of the Exit pupil In relation to the focal length for a comfortable visual observation, especially for spectacle wearers, too short

and from US4286844 a seven-lens eyepiece for a field of view of 90 °, in which a negative member in front of the

Intermediate image is arranged. This eyepiece has too much pupil aberration. An eight-lens eyepiece for a field of view of 85 ° to 90 ° is described in the patent US4720183. This eyepiece has

a good correction. But it has the disadvantage that the eyepiece diameter is large and some lenses have extreme shapes and thus the manufacturing cost is very high.

In the patent DD263606 a wide-angle eyepiece ar.gegeben, in the. from the side of the intermediate image to be imaged

towards the eye, a negative cemented member, a positive cemented member, a biconcave lens, a concavo-convex lens, and a weakly positive cemented member are arranged. This eyepiece has the disadvantage that the mass and the diameter are large and esfertigungstechnisch is expensive.

In the commercial patent WPG 02 B / 3115526 a wide-angle eyepiece is given, in which from the side of the imaged Intermediate image towards the eye a negative trilobal cementum, a positive two-part cementum, an aspherical one Biconvex lens and a positive meniscus lens are arranged. This eyepiece has the disadvantage of being a convenient one

visual observation to short distance of the exit pupil.

Object of the invention

The aim of the invention is to eliminate the disadvantages of the prior art and to provide a wide-angle eyepiece for a large field of view and sufficiently large cutting width of the exit pupil with a simple structure.

Explanation of the essence of the invention

The invention has for its object to provide a wide-angle eyepiece for a field of view of 90 ", in which the cutting width of the exit pupil is greater than 0.8 times the eyepiece bronnweite, the maximum free diameter of the lenses not greater than 2.6 times the Okularbren ^ is wide, the distortion correction corresponds to the angle condition and where the Petzval sum is corrected.

According to the invention, this object is achieved with a wide-angle eyepiece in that the wide-angle eyepiece is arranged from a Galilean system G, the negative member G, in the direction of the intermediate image to be imaged by the wide-angle eyepiece and is composed of a m positive Mehrlinsigen system S, wherein for magnification and the focal length of the Galilean system are advantageously satisfied with the following conditions:

Γ = - <0.7 (1)

If'i / uI> - 15Γ,, (2)

in which the symbols have the following meaning:

f'i - focal length of the t, ogative member of the Galilean system Γ »- focal length of the positive member of the Galilean system f'i / t - focal length of the entire Galilean system

The intermediate image to be imaged by the wide-angle eyepiece, for example after a telescope objective, represents a virtual object for the wide-angle eyepiece. The Galilean system images this virtual object into an enlarged real world image and this intermediate image is imaged by the positive multiline system such as through an eyepiece.

It is advantageous for a field of view of 90 ° that the Galilean system G consists of a negative cemented K ₁ of a negative lens Li and a positive lens L] and a biconvex lens L ₃ and the collecting system S of a positive cemented K ₂ K ₂ a positive lens L ₄ and a negative lens U, a biconvex lens U. whose surface facing the imaged intermediate image is aspherical, and a positive meniscus lens L ₇ . Dieso lens arrangement allows to reach from the lens L _{3 of} the Galilean system G to the aspheric surface of the lens U a nearly telecentric main ray pattern and so do not let the free diameter of the lenses to grow too strong. For a balanced correction of aberrations, the construction data given in claim 3 must be used.

embodiment The invention will be explained in more detail with reference to the following drawings. Show it

Fig. 1: the basic paraxial structure of the wide-angle eyepiece, Fig. 2: the lens sectional image of the wide-angle eyepiece.

In Fig. 1, the principal planes and paraxial ratios of the Galilean system G arranged along the optical axis OO 'from the side of the intermediate image P to be imaged are G consisting of a negative G, positive Gn, and positive S shown. By the Galilean system G, the virtual object P is enlarged in an intermediate image P 'in an intermediate image plane ZB and P' by the positive system S to infinity. Dash-dotted the main ray is shown for a field point. Fig. 2 shows the lens sectional image of the wide-angle eyepiece in which, along the optical axis OO ', from the side of the intermediate image to be imaged, a Galilean system G consisting of a negative cementing member K ₁ of a negative lens Li and a positive lens L ₁ and a biconvex lens L ₃ , and a collecting system S consisting of a positive cemented member Kj of a positive lens U and a negative lens Ls, a biconvex lens Lg whose surface facing the imaged intermediate image is aspherical, and a positive meniscus lens L ₇ . A balanced correction of the aberrations is by the described arrangement of the lenses Li to L ₇ with their radii r " thicknesses d _{j (} refractive indices n, and Abbe numbers v" the parameter a and the vertex radius T ₁ for the aspheric surface, wherein the arrowhead after following relationship depends on the distance to the optical axis h

2 α

1 - 1 -

2 α h ²

Γ ·

and the air gaps Ik whose values are given in Table 1. Table 1

Γ-1 -3.3780 1: 6.25 0,120 2 σ ' ** 90 ° ν. radii thick 1.7536 distances 0.384 r, = 54,74 4.0492 d, = 1,074 1.68101 r ₂ = 36.09 3.7872 d ₂ = 0,520 1.62410 h = -12.6900 Ii = 1,751 r ₄ = 28.12 7.1594 ds - 1,040 1.73430 't = -1.6887 Ij = 0.192 r «= 54,74 -17.0216 d «= 0.016 1.68101 r? - 25.52 ds - 1.79192 r, = I) =

f = 1 1.6962 aspherical 1: 6.25 radii -0.0015 thick distances r »" -5.1344 a " 1.5408 de = 0.840 no = 3.5792 I ₄ = 0.016 Γ11 =. d, = 0.480 Ή =

2 & = 90 ° n.

1.55440

1.55440

v.

63.2863.28

Claims (3)

claims: 1. Weitwinkelokuiar, consisting of three arranged along an optical axis members, characterized in that successively from the side of the intermediate image to be imaged from a negative member Gi, a positive member Gn and a positive mehrlinsiges member S are arranged, wherein the following conditions Equation are. <° ⁷ in which the symbols have the following meaning: f'i - focal length of the negative term G | f'n - focal length of the positive member Gh f'i / n - focal length, from term Gj to term Gh 2. Wide-angle eyepiece according to claim 1, characterized in that successively from the side of the imaged intermediate image of a negative cemented K ₁ from a N'egativlinse L ₁ and a positive lens L ₂ , a biconvex lens L ₃ and a collecting member S from a positive Kittglied K ₂ of a positive lens L ₄ and a negative lens L ₅ , a biconvex lens L ₆ , the abzubiidenden the intermediate image facing surface is aspheric, and a positive meniscus lens L ₇ are arranged. 3. Wide-angle eyepiece according to claim 2, characterized in that the following design parameters are present: wherein the arrow height ζ of the aspherical surface depends on the distance to the optical axis h according to the following relationship ζ = 2 α 1 - 2 α h