DD148391A1 - WIDE ANGLE LENS - Google Patents

Abstract

The invention relates to a wide-angle lens high relative opening of at least 1: 3.5 and small Baugroesze, in which a central collecting lens part is both object and image side enclosed by a respective scattering meniscus. The collecting objective part consists of 4 individual lens elements, with a nearly afocal cemented meniscus, which contains a monochromatically almost ineffective putty face and its convex surface facing the lens, arranged in front of the aperture, while after the aperture in the light direction a biconvex lens, a scattering and a collecting Meniscus follow, all their convex or staerker surface turn to the picture. By avoiding strong-acting putty surfaces, this lens construction is suitable for high-precision production by means of centering.

Description

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Title of the Invention: Wide Angle Lens

Field of application of the invention:

The invention relates to a wide-angle lens of high resolution, which is mainly used for photographic and fotograimnetrische purposes.

Characteristic of the known technical solutions: Known wide-angle lenses have a central collecting objective part, which is surrounded on the object as well as on the image side by a scattering meniscus each.

With regard to the central objective part, the individual inventions differ.

In the invention description CH 310552, the central lens part consists of four airspace-separated lens elements, while two lens elements are provided with cemented surfaces for chromatic correction.

In the invention description CH 449995 contains the collecting objective part two collecting through the diaphragm separate members, each of which contains at least one raised to the aperture cement surface.

In DD 49692 and DE-AS 1273853 wide-angle lenses are described, in which the central collecting objective part is composed of two collecting individual members, each of which contains a strongly bent collecting and scattering cement surface.

All lenses described have a great length, and above all, the free diameter at the first

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Lens very large, greater than 3 times the spherical bundle diameter. Furthermore, these lenses in the central collecting lens portion have lens members containing strong-acting cement surfaces, i. in which these cemented surfaces have strong curvatures and / or the refractive index differences at these surfaces are large. Lenses that avoid such extremely strained cemented surfaces are only suitable for small relative openings up to a maximum of 1: 5 · Furthermore, the lens elements of the central lens part are only separated by extremely small air spaces, and also for the installation of an aperture is little space available.

Because of the peculiarities described last, the known lens constructions are not suitable for the method of centering, which is considered the most modern production method. This process is described in the following literature:

Carnell et al .; Optica Acta 21 (1974) H. 6, p. 615-629 Sokolowa, J. S .; OPTION Mech. Prom. 1973, H. 7, p. 53

Object of the invention:.

The object of the invention is to provide a wide-angle lens that allows the application of centering (WP 80998) avoids strong-acting cement surfaces while still achieving a small size and a high aperture ratio.

Essence of the invention:

The invention has for its object to change the structural design of the central lens part in the known wide-angle lenses.

The object is achieved in a wide-angle lens high relative aperture of at least 1: 3.5 and a size less than 1.8 times the focal length, in which a central collecting objective part is both object and on both sides surrounded by a scattering meniscus, thereby in that the central collecting objective part is made up of 4 individual lens elements,

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a near-afocal cemented meniscus is placed in front of the aperture space, which faces its convex surface towards the object, while after the aperture in the light direction a biconvex lens, a scattering and a collecting meniscus follow, all of which turn their convex or more convex surface toward the image, and wherein the air space between the biconvex lens and the scattering meniscus is in the form of a condenser lens and the air space between the diffusing and collecting meniscus is in the form of a thin diverging lens. The difference between the refractive indices of the glasses used is less than 0.05 in the case of the almost afocal cemented meniscus in front of the aperture space. The design elements for a focal length f = 1 are given in Tables 1 to 3.

This invention has the advantage that the method of centering rotation can be used for the indicated lens arrangements. For this it is necessary that between the lens members sufficiently large distances are present.

Also, a sufficiently large aperture space is available for installing a panel or a closure. This wide-angle lens has a small size and a high light intensity of at least 1: 3> 5 · The free diameter of the first lens remain relatively small. There are no strong cemented surfaces.

A u sführungsbeispiel: _i

The invention will be explained in more detail in exemplary embodiments. Figures 1 and 2 show the arrangement and the shape of the individual lens elements. The central collecting lens part consists of 4 individual lenses or links. In the light direction in front of the aperture space, a meniscus 2 with a cemented surface is arranged. Behind the aperture space Ip, a biconvex lens 3 "a scattering and a collecting meniscus 4 and 5 are arranged. This objective part is surrounded by a scattering meniscus 1 and 6 both on the object side and on the image side.

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The meniscus 2 located in front of the aperture space is less effective and almost afocal. It contains a monochromatic almost ineffective cement surface, ie this cement surface is only for chromatic correction. The refractive index difference of the adjacent glasses is significantly smaller than 0.05. Said meniscus 2 applies its convex surface to the object and has a focal length which is at least 3 times greater in magnitude than the focal length of the overall objective. Its deflection must be of such magnitude that the diaphragm space takes the form of a schv / achen deflected converging lens, ie the diaphragm facing the hollow surface must be more curved than the diaphragm facing surface of the subsequent Biconvexlinse 3 «Due to the special structure of the inner member That is, by the arrangement of a scattering meniscus 4 behind the biconvex lens 3 and by the described design of the aperture space succeeds, in contrast to known wide-angle lenses with spherical-acting cement surfaces, an almost zone-free spherical and Komakorrektion. The biconvex lens 3, the scattering and collecting meniscus 4 and 5 all apply their convex or more convex surface to the image. In this case, the air space between the biconvex lens 3 and the scattering meniscus 4 has the shape of a converging lens and the air space between the scattering and the collecting meniscus 4 and 5 in the form of a thin diverging lens. Tables 1 to 3 show embodiments of the invention for a focal length f = 1 with relative openings between 1: 3.5 and 1: 2.8 and field angles between 2 er '= 80 ° and 2 (T = 92 °.

Figure 1 shows an arrangement which corresponds to the first two embodiments in Tables 1 and 2. Figure 2 shows an arrangement which corresponds to the 3 · embodiment according to Table 3. This last example is very fine-tuned for the vignetting-free opening and therefore achieves a very uniform resolution over the entire field of view and an extremely favorable light distribution in accordance with cosV

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Despite the high relative openings, all lens examples remain below 1.8 »f in length, and all lens examples have only 6 lincenes. In all examples, a low spherical aberration, an asymmetry error freedom and a good flattening of the meridional image shell were achieved.

In Tables 1 to 3, r ^ to r ^ denote the radii of curvature of the respective lens surfaces (at the left beginning in the respective figures), d ₁ to d ~ are the thicknesses of the lenses, 1 to I ₁ - are the spacings of the lens members, η the refractive indices for the green mercury line are λ S = 546 nm, ν are the Abbe numbers, f is the focal length and s ¹ is the image-side intercept. With the mentioned method of centering, the crimping centers of two optical surfaces, namely the outer boundary surfaces of a lens element, can be aligned exactly with the predetermined optical axis in this objective construction. Since the lens contains only one, namely a little effective Kittfläehe, the residual errors of this surface affect after the centering of the lens member 2 only very little on the image quality.

Table 1: (Embodiment 1)

£ a 1; relative opening 1: 3.4; Field angle 2 (T = 92 ° s ¹ = 0.354, length = 1.680.

radii + 0.5832 Thick and 0.0758 , refractive indices Abbe clearances ⁿ e Numbers ν T ₁ a + 0.3151 .1896 I d ₁ = 1.5186 63.9 + 0.7205 ι .1896 C. ¹ I ^B r ^ a - 0.8724 I 0.0443 1.6713 41.6 + 0.6719 .1580 4 d, = 1.6776 32.0 + 0.7490 .2453 I? I ₂ = r _A a - 0.4529 C 0.0885 D d _A = 1.5544 63.3 r ₇ a - 0.3617 .0860 / 1 is r _ft = - 0.5114 3 0.0190 O dc a 1.7343 28.1 r _Q a - 8,5078 Ό .1390 1 = ^r m - - 0.9905 .3691 IU d / - ss 1.6059 60.7 χ »s: - 0,4224 0.0758 tl lc = ^r 1? ~ - 1.7375 lc d ₇ = 1.6241 36.1 ^r 13 =

Table 2: (Embodiment 2)

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f = 1; relative opening 1: 2.8; Field angle 2 ο "= s ¹ = 0.334, overall length = 1.724

Radii Thicknesses and refractive indices

Air distances η numbers ν

e e

r. = + 0.5464

d = 0.0669 1.5590 58.3

T ₉ = + 0.3093 ^Ί

^ά I ₁ a 0.1591

r ^ »+ 0.7784 '

d _P = 0.1743 1.7279 37.7

d. = 0.0669 1.7231 29.3

Ip a 0.1490

d. a 0,2685 1,5914 61,0

1, = 0.0745

ας β 0.0796 1.7686 26.3

1. = 0.0088

d _A a 0.1553 1.6229 60.0

1 _ς = 0.4310

d ₇ = 0.0897 1.6776 32.0

^r 4 = - 1.9613 τ ₅ a + 0.6626 ^r 6 a + 0.8521 ^r 7 _8-0.4444 ^r 8 a - 0.3642 ^r 9 = - 0.4973 ^r 10 = - 3,2593 ^r 11 - - 0.9416 ^r 12 _s - 0.4349 ^r 13 = - 1,3478

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Table 3: (Embodiment 3)

f β 1; relative opening 1: 3.5; Field angle 2cT = 80 ° s' = 0.366; Length = 1.617

radii + .7589 Thick and β 0.0640 refractive indices Abbesehe clearances ⁿ e Numbers ν ^r 1 = + 0.3323 β 0.1791 I ^d 1 1.5186 63.9 χ s + 0.5407 I = 0.1791 I ₁ ^r 3 ⁼ +10.6284 I β 0.0512 ^d 2 1.7352 46.1 4 + 0.5407 C. = 0.1279 r »- d-j 1.7045 29.8 + 0.6893 = 0.2814 Γ /; = I ₀ - 0,4904 C = 0.0895 Trj B di 1.5709 62.9 / - 0.3789 4 = 0.1023 r _R β - 0.5168 j β 0.0256 r _Q β dj. 1.7919 25.5 y - 8,8615 = 0.1407 r = IU - 1.0924 4 = 0.2993 ^r i 1 " dy 1.6664 56.1 - 0,4249 β 0.0768 ¹ p ic - 1.6041 ^r 13 ⁼ d ₇ 1.6522 33.6

Claims (3)

Erfindungaanspruch; 1. Wide-angle lens of high relative aperture of at least 1: 3.5 and a size smaller than 1.8 times the focal length, in which a central collecting lens part is both object and image side enclosed by a respective scattering meniscus, characterized because d urch that the central collecting objective part is composed of 4 individual lens elements, wherein in front of the aperture space a nearly afocal cemented meniscus is arranged with its convex surface in the direction of the object, while downstream of the aperture in the light direction a biconvex lens, a scattering and a collecting meniscus all of which have their convex or more convex surface in the direction of the image, and the air space between the biconvex lens and the diffusing meniscus is in the form of a condenser lens and the air space between the diffusing and collecting meniscus is in the form of a thin diverging lens. 2. Lens according to item 1, characterized in that in the before. Aperture standing near afocal cemented meniscus, the difference of the refractive indices of the glasses used is less than 0.05. 3. Lens according to item 2, characterized by the design elements given in Table 1 for a focal length f = 1. For this 1 page drawing