DE2156222C3 - Reproduction lens - Google Patents

Description

= + 34.246 d, m nd V rl = + 19.257 dl = 1.36 1.59551 39.2 rl = + 19.257 wl = 0.15 air r3 = 4-1837.150 dl = 4.49 1.65844 50.8 r4 = - 48.439 ml = 3.75 air rS = 4- 29.478 ί / 3 = 1.47 1.57845 41.7 r6 = - 144.764 w3 = 3.90 air rl = 4- 27.948 ί / 4 = 1.25 1.54869 45.4 / ■ 8 = - 36.259 ί / 5 = 5.15 1.65844 50.8 r9

where rl to r9 denote the radii of curvature, i / l to i / 5 the axial thicknesses of the individual lenses, ml to / h3 the air gaps between the individual members, nd the refractive index for the spectral line d and υ the Abbe number.

2. Reproduction objective, in particular for reproducing the image at a magnification ratio of I: 1, which is formed from five lenses which are axially arranged so that the first lens closest to the object plane is a Meniscus of negative refractive power and the second lens is a meniscus of positive refractive power, wherein these two lenses are either cemented or separated by an air gap and all their refractive surfaces are convexly curved towards the object plane, so that the next lens is biconcave Lens is and of the following two cemented lenses, the first lens and the biconcave second lens is biconvex, characterized by the following parameters:

rl = + 33.769
rl = I 19.080
/ • 3 = 4 1014.67

r4 = -
/ • 5 = -f- 1-6 = -
rl = 4
/ ■ 8 = -

48,439
29,478
144.764
27.948
36.259

d, in

dl = 1.10

dl = 4.41
m I = 3.68

i / 3 = 1.47
ml = 4.23

i / 4 = 1.25

i / 5 = 5.15

nd

1.59551

1.65844

air

1.57845

air

1.54869

1.65844

39.2
50.8

41.7

45.4
50.8

where rl to r8 denotes the radii of curvature, i / l to i / 5 denote the axial thicknesses of the individual lenses, ml to ml the air gaps between the individual lenses is formed from five lenses which are axially arranged so that the first,

ίο the lens closest to the object plane Meniscus of negative refractive power and the second lens is a meniscus of positive refractive power, these two being Lenses are either cemented or separated by an air gap and al! E their refractive Surfaces to the object plane are convexly curved, that the next lens is a biconcave lens and from of the following two cemented lenses, the first lens is biconcave and the second lens is biconvex.

Lenses of the same or similar type are

generally known and are mainly used for reproduction and enlargement purposes and also for projection and recording purposes (German utility model 17 32 711) use *. The first lens element of these lenses usually shows positive

Refractive power and is either a simple converging lens or a cemented link. The taking lens known from the German utility model 17 32 711 is designed in such a way that residual errors which impair image sharpness are largely eliminated even with large aperture ratios of 1: 3.5 or more. The correction status of the lenses intended for reproduction purposes is regulated in such a way that, when the focal length of the lens and the format of the original are specified, it primarily fulfills the condition of a perfect image drawing. The magnification ratio of reproduction lenses, e.g. B. for the format of the original of 13-18 mm and a focal length of 35 mm, is usually limited to the range from 2x to 6x, whereby the most perfect image drawing due to the state of correction is at the medium magnification, in this one So the case is at 4x magnification. With the two extreme enlargements of the range mentioned, ie for the 2-fold or 6-fold enlargement, the quality of the reproduced image is considerably poorer and if these two extreme enlargements are exceeded, the drawing is generally inadequate. This is particularly noticeable at small magnifications, so that these lenses for z. B. a simple magnification cannot be used with success.

An analogous situation also arises in the case of the light distribution in the image plane.

At medium magnifications, i.e. H. a 4x magnification, the vignetting is usually not higher than 40%, but with larger magnifications it rises over 50% and such a light distribution is usually no longer acceptable. Similar to the state of correction, it is also unsatisfactory

Vignetting for a reproduction ratio of 1: 1 is still relatively high, so that for a demanding user These lenses are not suitable for reproduction at the magnification mentioned.

Known reproduction objects of the ones mentioned

Types that are only available for a given magnification, e.g. IB. designed for 1: 1 scale illustrations are suitable with regard to the state of correction for this given magnification, the vignetting

tion seldom sinks below 40%, which is especially true for special devices with which a uniform Light distribution in the image plane is required is unacceptable.

The object of the invention is therefore to create a reproduction lens which is simple in number of the lenses the well-known constructions of reproduction objectives not exceeding design, when using common types of glass and for the reproduction scale 1: 1 a good image drawing over the entire area of the field of view with practically Eliminated distortion guaranteed. The vignetting of the lens in the format corners should be 20% do not exceed.

This task is accomplished by designing the lens of the type mentioned at the beginning with the design data solved according to one of the data table listed in the characteristics of claims 1 and 2.

By selecting the focal lengths of the individual lenses of the optical system, the Radii of curvature of the individual breaking surfaces, the axial thicknesses and the air gaps was achieved that the vignetting of the lens with slight residual aberrations for images on a scale of 1: 1 and at a light intensity of 1: 5.6 is practically zero.

In the drawings, the two reproduction objectives according to the invention are shown schematically in cross section. The reproduction objective according to FIG. 1 consists of five lenses, all of which, with the exception of the last two lenses, which are assembled to form a cemented element, are single. The values of the radii of curvature of the adjacent refractive surfaces of the first and second lenses are either the same or differ only slightly. In the case of the second reproduction objective, the two lenses are cemented, as shown in FIG. The individual lenses of the system are _{labeled L 1} to L ₅ , the cemented element with A, the radii of curvature of the individual refractive surfaces with r _x to r _g , the thicknesses of the individual lenses with d _x to i / ₅ , the air gaps between the individual optical elements Divide with / W ₁ to / M ₃ . The object plane is designated with P and the image plane with O. The thicknesses and gaps are given in millimeters, these values being measured on the optical axis.

The data tables below contain the construction data of the two reproduction objectives according to the invention given, whereby these data are converted to the focal length / = 100 mm; the relative aperture of the lenses is 1: 5.6.

The first data table relates to the reproduction objective in which the first two lenses L _x and L _{2 are} separated by an air gap, while the second data table relates to the reproduction objective in which the two mentioned lenses are joined together to form a cemented member.

Data table 1

rl = + 34.246
rl = + 19.257

r3 =
rA =
r5 =

19.257
1837,150
48,439
29,478
144.764
27.948

r9 = - 36.259

with / Ll = -76.4714

fLl = +29.5273

/ L 3 = -31.4932

fA = +54.4804

r8 =

d, m

d = 1.36
ml = 0.15
dl = 4.49
ml = 3.75
</ 3 = 1.47
/ M 3 = 3.90
d4 = 1.25
dS = 5.15

nd

1.59551

air

1.65844

air

1.57845

air

1.54869

1.65844

39.2 50.8 41.7

45.4 50.8

Data table 2 d, m

nd

rl = + 33.769 dl = 1.10 1.59551 39.2 rl = + 19.080
r3 = +1014.670

dl = 4.41
/ wl = 3.68

ί / 3 = 1.47
ml = 4.23

1.65844

air

1.57845

air

1.54869

1.65844

50.8 41.7

45.4 50.8

r4 = - 48.439

r5 = + 29.478

_r 6 = - 144.764 c / 4 = 1.25

r7 = I- 27.948 </ 5 = 5.15

r8 = - 36.259

with / Ll = -75.7752

fLl = +29.4811

/ L 3 = -31.4932

fA = +54.4804

In both data tables, rl to r8 and r9 denote the radii of curvature of the lens surfaces, dl to t / 5 the axial thicknesses of the individual lenses, / wl, ml and m 3 the air gaps between the individual lens elements, nd denotes the refractive index for the spectral line d and ν is the Abbe number. The indices of the radii r correspond to the sequence of the lens surfaces starting from the first lens Ll to the fifth lens L5. The index of the thicknesses d corresponds in each case to the index of the associated lens. The index of the column m corresponds in each case to the index of the respective previously arranged lens (e.g. ml is the gap between the first and second lens).

The reproduction objectives according to the invention are suitable for reproducing the image in a Magnification of Ix. After correcting the distortion and reducing the remaining aberrations is the vignetting is practically zero, which guarantees an even distribution of light over the entire image format. For these reasons, the objectives according to the invention are particularly suitable for xerographic Reproduction devices.

For this purpose 2 sheets of drawings

Claims (1)

Patent claims: 1. Reproduction objective, especially for reproduction of the image at a magnification ratio of 1: 1 made up of five lenses which are axially arranged so that the first lens closest to the object plane has a meniscus negative refractive power and the second lens is a meniscus of positive refractive power, these both lenses are either cemented or separated by an air gap and all of their refractive surfaces are convexly curved to the object plane that the next lens one; biconcave Lens is and of the following two cemented lenses, the first lens is biconcave and the second Lens is biconvex, characterized by the following parameters: Divide, nd the refractive index for the spectral line and ν the Abbe number.