DD148391C2 - WIDE ANGLE LENS - Google Patents

Description

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 fotograrametrische 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 of four airspace-separated lens members, while two lens elements are provided with cemented surfaces 5 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 49 ^ 92 and DE-AS 1273853 wide-angle lenses are described, in which the central collecting objective part is made up 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

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 components of the central objective part are only separated by extremely small air spaces, and there is also limited space for installing an aperture available.

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

Carnell et al .; Optica Acta 21 (1974) H. 6, p. 5 - 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 is based, to change the structural design of the central lens part in the known wide-angle lenses the task

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 image side enclosed by a scattering meniscus, thereby in that the central collecting objective part is made up of 4- individual lens elements,

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 Blendenraura 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 diameters on the first lens remain relatively small. There are no strong cemented surfaces.

Embodiment:

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 enclosed on both the object and on both sides by a scattering meniscus 1 and 6 each.

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 weak, deflected converging lens, that is, the aperture facing the hollow surface must be more curved than the diaphragm facing surface of the subsequent Biconvexlinse 3 ·. By special construction of the inner member, ie 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 2ο" β 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 shown in Table 3 · This last example is feinstkorrigiert for the vignetting free opening and thus achieves a very uniform resolution over the entire field of view and a very favorable light distribution according coser he

Despite the high relative openings all lens examples remain in the overall length below 1.8 »f, and all lens examples have only 6 lens elements · In all examples, a low spherical aberration, a Asymmetrlefehlerfreiheit and a good flattening of the meridional image shell is achieved ·

In Tables 1 to 3, г .. to г .. ^ represent 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, I ₁ to 1, the distances are Lens elements, η are the refractive indices for the green mercury line λ = 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 center of curvature of each of two optical surfaces, namely the outer boundary surfaces of a lens member, can be aligned exactly to the predetermined optical axis in this lens design · Since the lens contains only one, and a little effective Kittfläehe act the residual errors of this surface after the centering of the lens member 2 only very little on the image quality.

Table 1 ; (Embodiment 1)

f = 1; relative opening 1: 3.4; Field angle 2 (T = s · = 0.354, length = 1.680

Radii Thicknesses and refractive indices Abbe

Air distances η numbers ν

e e

T ₁ = + 0.5832

¹ d = 0.0758 1.5186 63.9

T ₂ = + 0.3151 ^Ί

^d I ₁ s 0.1896

r- »+ 0.7205 ^Ί

* d ~ - 0.1896 1.6713 41.6

r, »- 0.8724 ^ά

⁴ d, - 0.0443 1.6776 32.0

r _R = + 0.6719 *

^p I ₉ = 0.1580

r _A = + 0.7490 ^

^b d, = 0.2453 1.5544 63.3

T ₇ = - 0.4529 *

¹ 1- - 0.0885

r _ft = - 0.3617 ^

^ö de = 0.0860 1.7343 28.1

r _q = - 0.5114 °

^y 1 _A = 0.0190

r _in = - 8,5078 ⁴

^1U d _A = 0.1390 1.6059 60.7

T ₁₁ = - 0.9905 ^D

^ΊΊ 1 _ς = 0.3691 r _1P = - 0.4224 ⁵

^Ίίί d ₇ = 0.0758 1.6241 36.1

r ₁₃ = - 1.7375 '

• t

Table 2; Example 2)

fa 1; relative opening 1: 2.8; Peld angle 26 * = a ¹ «0.334; Length = 1.724

radii _r C χ r 11 s + 0.5464 Thick and 1 = 0.0669 refractive indices Abbe Г-, clearances ⁿ e Numbers ν = + 0.3093 ^d 7 β 0.1591 ^r 13 ^d 1 f 1.5590 58.3 4 ^r 7 = + 0.7784 I = 0.1743 / I ₁ Гд = - 1.9613 1   .0669 O do 1.7279 37.7 ^r Q = + 0.6626 = 0.1490 У 1.7231 29.3 = + 0.8521 m 0.2685 I U I ₂ = - 0,4444 C. = 0.0745 ^d A 1.5914 61.0 = - 0.3642 = 0.0796 1 β - 0.4973 = 0.0088 1.7686 26.3 = - 3,2593 = 0.1553 1 _A = - 0.9416 4 = 0.4310 ^d 6 1.6229 60.0 = - 0.4349 о = 0.0897 = - 1,3478 1.6776 32.0

Table 3: (Example 3)

f = 1; relative opening 1: 3.5; Peld angle 2cT = s ¹ = 0.366; Length = 1.617

radii Thick and refractive indices ⁿ e Abbe clearances Numbers ν _β г- = + 0.7589 , 5186 ¹ d ₁ = 0.0640 1 63.9 Гр = + 0,3323 I ₁ = 0.1791 г, = + 0.5407 Ί , 7352 i dp = 0.1791 1 46.1 г. = + 10.6284 , 7045 4 d, = 0.0512 1 29.8

г _ц = + 0.5407 ^J

⁵ Ip = 0.1279 Tr = + 0.6893

^b d, = 0.2814 1.5709 62.9

r ₇ = - 0.4904 ⁴

'I. = 0.0895

г _й = - 0,3789 ^J

^ö d. = 0.1023 1.7919 25.5

r _Q = -0.5168 ⁵

^y La 0.0256

r. _n = - 8.8615 ^

^ιυ ar = 0.1407 1.6664 56.1

T ₁₁ = - 1.0924 °

¹¹ 1 _ς = 0.2993 rp = - 0.4249 ⁵

^Ίίί d ₇ = 0.0768 1.6522 33.6 r ₃ = - 1.6041 ^r

Claims (5)

Invention entitled; 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 objective part is surrounded both object and image side by a scattering meniscus, characterized in that the central collecting lens 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 after the aperture in the light direction a biconvex lens, a scattering and a collecting meniscus are arranged downstream, 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 has the shape 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 the difference between the refractive indices of the glasses used is less than 0.05 in the standing before the aperture space almost afocal cemented meniscus. 3. Lens according to item 2, characterized by the design elements given in Table 1 for a focal length f = 1. Table 1; (Embodiment 1) f = 1; relative opening 1: 3.4; Field angle 2tf = 92 s ¹ = 0.354; Length = 1,680 Radii Thicknesses and refractive indices Abbe Air distances n "numbers ν e e 4. Lens according to item 2, characterized by the design elements given in Table 2 for a focal length f = 1. Table 2: (Embodiment 2) relative opening 1: 2.8; f = 1; s' = 0.334 Field angle 2C = 85 Length = 1.724 radii Thicknesses and air gaps Refractive indices Numbers ν 5. Lens according to item 2, characterized by the design elements given in Table 3 for a focal length f = 1 · Table 3: (Embodiment 3) f * 1; relative opening 1: 3.5; Field angle 2C = 80 ° s ¹ = 0.366; Overall length «1.617 For this ή page drawing