DE1175905B - Magnifying lens - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: G 02 b

German class: 42 h -6/10

Number: 1175 905

File number: A 40166IX a / 42 h

Filing date: May 9, 1962

Opened on: August 13, 1964

The invention relates to a magnifying lens which consists of three members, one of which each of the outer links is composed of a collecting and a dispersing part Is a cemented element of positive refractive power, which contains a raised, converging cement surface against the inside of the lens, while the inner link is a single biconcave lens.

Five lenticular magnifying lenses in triplet variants have become known, the z. ^{B. be able to reproduce a negative format 60 × 90 mm 2} linearly from 6 to about 1.5 times magnification relatively well in an embodiment focal length of about 95 to 105 mm. These lenses, which have become known, are primarily intended for use with enlargers.

Other requirements are usually made for roll copier machines. With conventionally designed enlargers, mainly constant negative sizes are enlarged to different, very different positive formats; for roller cutting machines, however, are all commercially available negative formats, that is 18 · 24, 24 · 36, 40 · 40.45 · 60, 60 · 60 and 60 · 90 mm ² to a constant positive formats of 60 x 90 or 90 x 120 mm ^2, and so increases will. For this given example, the magnifying lens should be well corrected for the magnification range from 1 to at least 5 magnifications. Since color negatives as well as black and white are to be processed, the lens correction must be extended to the extended spectral range from around 350 to 720 My at the same time.

For certain roll copying machines, there are often conditions for purely mechanical reasons, which have a relatively large variable negative-positive distance and thus a relatively long focal length of the lens require between about 100 and 160 mm. From this it follows that the angular stress the lens is relatively small; however, the correction of all the image errors must go much further are driven in comparison to the more popular lenses of shorter focal lengths. Similar as with telephoto lenses with interchangeable recording lenses, despite the smaller angle of view in comparison to the resolving power of normal or wide-angle lenses, the resolving power be very large considering the longer focal length.

It was found that the comatic and astigmatic corrections prescribed in the lenses Structure is favored by the fact that, on the one hand, the single biconcave negative lens - Magnifying lens

Applicant:

Agfa Aktiengesellschaft, Leverkusen,

Kaiser-Wilhelm-Allee 24

Named as inventor:

Dr. Christian Otzen, Grünwald near Munich

in contrast to the previously known construction principle for magnifying lenses - with the more strongly curved surface (i? ₄ ) facing the positive plane, according to the mathematical relationship

\ R _t \ <R _s ,

and on the other hand this biconcave negative lens is arranged between the positive outer members in such a way that the axial air gap in front of the negative lens Z _{1 is} greater than 5 times, but smaller than 10 times the amount of the axial air gap I ₉ lying behind the negative lens, according to the mathematical relationship:

5 Z ₂ < I ₁ <10 I ₂ .

According to the invention, the comatic, chromatic and spherical correction and the distortion are favorably influenced if the deflection of the single negative lens is chosen so that the more curved radius (R ₄ ) facing the positive plane is between 0.5 and 0 in absolute terms. 9 times the value of the flatter radius (R ₅ ) , according to the mathematical relationship:

0.5i? ₅ <| i? ₄ | <0.9 # ₅ .

By fulfilling these relationships it has been possible to create a magnifying lens of a 51insigen, To provide 3-link triplet variant, in which for the magnification range from 1 to 6 times magnification, despite the relatively long focal length, the error elimination so far and evenly is carried out that the image performance in the spectral range from 350 to 720 My is already at full opening and an edge brightness of about 90% practically no more residual defects.

The objective example listed below has the features according to the claims. It is for a focal length / = 1.0 and an aperture ratio of 1: 4.5 and for the magnification

409 640/188

Corrected range from 1.0 to 6 times magnification. The radii are with R ₁ . .. R ₈ , the axial lens thicknesses with ^ ₁ ... d _s , the axial air gaps with / j and I ₂ , the refractive indices of the glasses with. The refractive indices refer to the wavelength of 587.6 My. The construction elements are numbered consecutively, in the direction of the negative plane N to. The positive

/ J ₁ ... / J ₃ and their Abbe numbers with V ₁ ... v ₅ 5 level is indicated by P.

example

Magnifying lens 1: 4.5 focal length / = 1.0 corrected from 1.0 to 6 times magnification

R ₁ = +0.53758
R., = -0.41462
Rl = +6.11841
A ₄ = -0.25703
R ₅ = +0.35283
R ₆ = +1.29748
A ₇ = +0.24949
R _u = -0.28523

Cl ₁ = 0.06182 d, = 0.02021 / ~ = 0.18125 rf, = 0.02074 4 = 0.02487 d _i = 0.01494 d. = 0.08349 / J ₁ = 1.62041
/ j, = 1.56138

V ₁ = 60.29
ι ·., = 45.27

/ J ₃ = 1.53172 BC _t = 48.87

n ₄ = 1.51742
/ J ₅ = 1.62041

Area 1
Area 2
Surface 3
Area 4

Surface powers) n / R 1.15408 area 5

+ 0.14237 -0.09175 -2.06871 area 6
Surface 7
Area 8

r ₄ = 52.16
v. = 60.29

-1.50701
+ 0.39879
- ^ 0.41280
-1-2.17512

The drawing shows the section through a lens according to the example.

Claims (3)

Patent claims: 1.Three-section magnifying lens, in which each of the two outer sections consists of a 30 collecting and a dispersing part Putty element of positive refractive power, each one raised towards the inside of the lens, contains collecting cemented surface, while the inner member is a biconcave single lens, marked 35 is characterized by the simultaneous fulfillment of the following conditions: 40 R ₁ = + 0.53758 /
-0.41462 /
+ 6.11841 /
-0.25703 /
+ 0.35283 /
+ 1.29748 /
+ 0.24949 /
-0.28523 / Cl ₁ = 0.06182 / d ₂ = 0.02021 / ₁ = 0.18125 / = 0.02074 / = 0.02487 / l = 0.01494 / d _r = 0.08349 / 2. Three-part magnifying lens according to claim 1, characterized by the fulfillment the condition: 0.5 R. <R _t <0.9 R- (C) 3. Three-part magnifying lens according to claims 1 and 2, characterized in that the refractive powers A, n / R each by a maximum of ± 0.3 // and the axial lens thicknesses (d) and the axial air gaps (/) each by a maximum of 10 ° / o the overall length of the lens deviate from the values shown in the following numerical example: / J ₁ = 1.62041
/ j., = 1.56138 V ₁ = 60.29 v., = 45.27 / 7 _{: j} = 1.53172 v ₃ = 48.87 1.51742
1.62041 v ₄ = 52.16
v- = 60.29 Surface powers A n / R Area 1
Area 2
Surface 3
Area 4 + 1.15408 // -0.14237 // -0.09175 // -2.06871 // Area 5
Area 6
Surface 7
Area 8 -1.50701 /
+ 0.39879 /
+ 0.41280 /
+ 2.17512 // where the radii with R ₁ ... R _s , the axial lens thicknesses with ^ ₁ ... J ₅ , the axial air distances with I ₁ and I ₂ , the lens focal length 60 with / and the refractive indices of the glasses for the wavelength 587 , 6 My with / J ₁ ... n. And their Abbe numbers with V ₁ ... V ₅ . 1 sheet of drawings