EP3864455A1

EP3864455A1 - Optical assembly, optical instrument and method

Info

Publication number: EP3864455A1
Application number: EP18788695.7A
Authority: EP
Inventors: Peter Kaszian
Original assignee: Eardley Holding Ag
Current assignee: Eardley Holding Ag
Priority date: 2018-10-09
Filing date: 2018-10-09
Publication date: 2021-08-18
Also published as: BR112021005488A2; US20210392248A1; KR20210069069A; MX2021002831A; RU2768520C1; AU2018445019A1; WO2020074065A1; CA3111041A1; SG11202102838XA; CN112805608A; IL282149A

Abstract

The invention relates to an optical assembly (100) comprising a first objective unit (10) and a second objective unit (20), wherein an intermediate image plane (2) is defined between the first objective unit and the second objective unit, wherein the first objective unit (10) is designed to project an image from a first image plane (1) in the form of an enlarged real intermediate image in the intermediate image plane (2) and wherein all the possible beam paths through the first objective unit define a first inlet region (11) in the first image plane and define a first outlet region (12) in the intermediate image plane, wherein the second objective unit (20) is designed to project an image from the intermediate image plane (2) in the form of an enlarged real image in a second image plane (3) and wherein all the possible beam paths through the second objective unit define a second inlet region (21) in the intermediate image plane and define a second outlet region (22) in the second image plane, and wherein the second inlet region (21) comprises a first portion of the first outlet region and excludes a second portion of the first outlet region. The invention also relates to an optical instrument comprising the optical assembly, and a method.

Description

Optical assembly, optical instrument and method

The present invention relates to an optical assembly. The invention further relates to an optical instrument which comprises the optical assembly and a method for increasing the resolution of an optical instrument.

Passive optical instruments expand the possibilities of the eye, both in terms of its resolving power and in terms of its brightness perception. Brightness

differences, widely distributed spatial positions and

Color differences of objects are reflected in light

packets of information that when used with

sufficient energy can be transported over long distances, received with telescopes and unfolded and presented as two-dimensional image information. Brightness, space and color information that condenses in a very small space

can be made available for further use with the aid of the microscope.

For the resolution of the naked eye, the

Distance of 25 cm is regarded as the conventional visual range or reference visual range. Here the eye can achieve the best spatial resolution for longer periods. If the object is held close to the eye between 25 and 10 cm, a correspondingly better one can be used for short periods

Spatial resolution can be achieved. With relaxed eyes and Larger distances, several meters to infinity, is the typical angular resolution of the

human eye 1 minute of angle.

Passive optical instruments are made for different purposes. Your features will be

basically optimized for the respective field of application. E.g. can magnify the telescope or microscope

expediently be increased until the

Angular resolution of the optical device to that of the

human eye. One then speaks of the useful enlargement. A magnification that is too strong, on the other hand, where the visual contrast becomes too low, is called a dead magnification. Have classic imaging systems such as telescopes, photo cameras and microscopes

basically building a specialized lens,

Specialized eyepiece and / or image sensor, telephoto lenses or astroobjectives are specifically adapted for increasing distance and macro lenses, microobjectives and nanoobjectives are specifically adapted for increasing compression of the optical information.

Focal length-extending optics (so-called extenders), image-transmitting optics (so-called relay optics) and a projection lens can be mounted between the lens and eyepiece / storage medium as well as a projection lens in the projection microscope. In all these cases the quality, i.e. the resolution and contrast of the images.

It is true that the image section can be reduced in this way, ie there is an enlargement of the viewed Object, but at the expense of sharpness and

Richness of detail.

The object of the present invention was to provide an alternative device or an alternative

To provide methods with which the optical resolution can be improved.

This object is achieved by the features specified in claim 1. Advantageous embodiments of the invention are specified in dependent claims.

The present invention relates to an optical assembly comprising a first lens unit and a second

Lens unit. An intermediate image plane is defined between the first lens unit and the second lens unit. The first lens unit is set up to image an image from a first image plane into an enlarged real intermediate image in the intermediate image plane. A set of possible beam paths through the first lens unit defines a first entrance area in the first image plane and defines it in the

Intermediate image level a first exit area. The second lens unit is set up to image an image from the intermediate image plane into an enlarged real image in a second image plane. A set of possible beam paths through the second lens unit defines a second in the intermediate image plane

Entry area and defined in the second image plane a second exit area. The second entry area comprises a first part of the first exit area and excludes a second part of the first exit area.

The first image plane lies on the entry side of the first lens unit and the second image plane lies on the exit side of the second lens unit. An optical axis can pass from the entry side of the optical assembly through the first lens unit and the second

Lens unit run through to an exit side of the optical assembly. In this case, the first image plane, the second image plane and the

The intermediate image plane is essentially perpendicular to the optical axis. The image in the first image plane can be formed by an object to be imaged, or it can itself be a real intermediate image which is generated by an optical system connected upstream of the optical assembly according to the invention. That in the second

The resulting enlarged real image has the desired increased resolution. This enlarged real image that arises in the second image plane can be further enlarged by further subsequent optical elements, viewed through an eyepiece or recorded with an image sensor.

The first lens unit has a first entrance opening and a first magnification factor greater than 1, both of which are the possible beam paths through the first Affect lens unit. Likewise, the second one

Lens unit a second entrance opening and a second magnification factor greater than 1, both of which influence the possible beam paths through the second lens unit. The first and second entry areas as well as the first and second exit areas are flat

Areas within the respective level in which they are defined. The first exit area and the second entry area are both defined in the intermediate image plane. It is characteristic of the optical assembly according to the invention that only part of the first

Exit area is overlapped by the second entry area. You can zoom into a detail at this overlap area, so to speak. Only rays that belong to a section of the intermediate image enter through the opening of the second lens unit. I.e. in contrast to a so-called relay optics, not the whole

Intermediate image taken in the subsequent second lens unit and it results from both

Lens units an enlargement.

In the simplest case, the lens units can consist of a single lens. The lens units can also include mirrors as elements. The first lens unit and the second lens unit can each be constructed as a group of lenses. The two lens units, and optionally other optical elements, can be installed in a common outer tube. Such an outer tube can, for example, on the inside Grooves are provided or blackened to prevent stray light

to minimize within the optical assembly.

In particular, elements can be provided which prevent indirect radiation paths from the second part of the first exit region from entering the input opening of the second lens unit.

It is a cascading arrangement of several

Optical assemblies according to the invention are possible, as will also be explained below in connection with exemplary embodiments. Due to its property as

magnifying lens unit includes the first

Entry area a first part of the first image plane and excludes a second part of the first image plane. With a suitable arrangement of a further lens unit in front of the first lens unit, an exit region of the further lens unit can be positioned with respect to the first image plane in such a way that the further lens unit and the first lens unit form a further optical assembly according to the invention, the further

Lens unit has the role of the first lens unit of the further optical assembly and the first

Lens unit of the first-mentioned optical assembly, the role of the second lens unit of the other

has optical assembly.

The optical assembly according to the invention could be used as

Multiproj ejection module, because there is at least twice a real intermediate image - a projection - generated, namely in the intermediate image plane and in the second image plane.

As the inventor has recognized, when using the optical assembly according to the invention, those mentioned above occur

Disadvantages of the prior art, such as lower resolution or decreasing contrast in relay optics and / or

Extenders, when not zooming in on an object, on the contrary, the image quality of the

original lens dramatically.

In one embodiment of the optical assembly, the first lens unit has a first focal length and the second lens unit has a second focal length. The distance from the first lens unit to the intermediate image plane defines a first image width and the distance from the second

Lens unit to the second image plane defines a second image width. According to the embodiment, a ratio of the first focal length to the first image width is in the range 1:10 to 1: 1000. Alternatively or in combination with the feature mentioned, a ratio of the second focal length to the second image width is in the range 1:10 to 1: 1000.

In contrast to relay optics, in which a focal length / image width ratio is in the range 1: 1 to 1: 2, according to the present embodiment of the invention, the image width is significantly larger than the focal length of the

respective lens unit. The image width is to be understood as the distance from the last lens of the lens unit to the real intermediate image generated. For example, the first lens unit have a focal length of 11 millimeters and be designed for an image width of 150 millimeters, that is to say have a focal length / image width ratio of approximately 1: 13.6. In another example according to the embodiment, the first lens unit can have a very short focal length of 0.2 millimeters and can be designed for an image width of 150 millimeters, that is to say have a focal length / image width ratio of 1: 750. The second lens unit can have a focal length-image width ratio according to one of the examples for the first

Lens unit.

The inventor has recognized that the imaging quality according to this embodiment is particularly high.

According to one embodiment, the ratio of the first focal length to the first image width and / or the ratio of the second focal length to the second image width is greater than or equal to 1:40.

The inventor has recognized that in this embodiment it is possible to achieve magnification factors of over 1000 times for the entire assembly with very high optical quality at the same time. This is particularly the case if both the ratio of the first focal length to the first image width and the ratio of the second

Focal length to the second image distance is greater than or equal to 1:40. According to one embodiment, the first and / or the second lens unit has an infinite structure

corrected lens.

In particular, the first and / or second objective unit can have the structure of an infinitely corrected microscope objective. Under infinity corrected lens is a

To understand objectively which is corrected to infinity with respect to at least one of the following aberrations:

- Chromatic aberration,

- spherical aberration,

- astigmatism,

- coma.

In particular, several of the aberrations mentioned or all of the aberrations mentioned can be substantially corrected to infinity. Corrected to infinity means that the correction applies to every point behind the lens.

The inventor has recognized that this embodiment leads to surprisingly high imaging quality. The correction of the aberrations mentioned does not only affect the properties that one would expect - for example, the correction of the chromatic

Aberration in the reduction of unwanted color fringes at light-dark transitions - but surprisingly, the one that can be achieved with the optical assembly is also

Resolution greatly improved.

Great improvements in the achievable resolution are achieved by first and / or second lens units, which both have an infinitely corrected structure, and where the ratio of the focal length to the

Image width is greater than or equal to 1:40.

According to one embodiment, the area of the first part of the first exit area is at most one tenth of the area of the first exit area.

According to this embodiment, the excluded second part of the first exit area is much larger than the first part of the first exit area, which corresponds to the second entry area and which is further enlarged by the second lens unit. The area of the first part of the first exit region can

for example a twentieth of the area of the first

Exit area or less.

In one embodiment, there is at least one other

Lens unit next to the second lens unit

arranged and the at least one further lens unit is set up to convert an image from the intermediate image plane into an enlarged real image in another

Map image plane. A set of possible beam paths through the further objective unit defines a further entry area in the intermediate image plane and defines a further exit area in the further image plane, the further entry area being different from the first entry area.

In this embodiment, the further lens unit has the same function as the second lens unit Exception that it is directed to another entry area. A number of such others

Objective units can be arranged next to one another, for example in the manner of a compound eye

Insect. Each of the other lens units can

for example, be formed by a single lens. The further entry areas can be arranged, for example, in a hexagonal arrangement, the further entry areas being able to overlap slightly with one another or with the second entry area at the edge. In this way, parts of the image can be drawn from a large part of the first exit area or from the entire first

Exit area over a plurality of parallel

working further lens units without gaps

recorded and further enlarged. These

Embodiment of the optical assembly can, for example, be installed in an optical instrument, in which the further objective units each have a separate one

Image sensor are arranged. The second lens unit and the further lens units can each be a spherical or an aspherical lens in one

Microlens array can be formed, such

Microlens array can comprise 100 to 1000 individual microlenses, that is to say further lens units arranged in parallel.

In one embodiment of the optical assembly, the first lens unit is configured in such a way that it passes through different radial areas of the first lens unit Focus points formed in the area of the intermediate image plane in the direction of an optical axis of the first lens unit are less than 500 nanometers apart, preferably less than 50 nanometers apart. Alternatively or in combination with the above-mentioned configuration of the first lens unit, the second lens unit is designed such that the focal points formed by different radial areas of the second lens unit in the

Area of the second image plane in the direction of an optical axis of the second lens unit are less than 500 nanometers apart, preferably less than 50 nanometers apart.

The extension in the direction of the optical axis of the

Area in which the focus points of a lens unit fall, i.e. the extent of the area in which the paraxial focus, the center zone focus and the

Edge ray focus is a measure of spherical aberration. In this embodiment, the spherical aberration of the first and / or the second lens unit is corrected to a high or very high degree. Of the

The inventor has recognized that the quality of the image is due to a low spherical aberration of the individual

Objective elements in the arrangement according to the invention to form an optical assembly are surprisingly greatly improved.

A low spherical aberration can be achieved by a suitably shaped aspherical lens or lens groups with at least one suitably shaped aspherical lens, which are built into the lens unit. A another way to reduce spherical aberration

correct one by thickness and

Refractive index-defined aberration correction plate with plan, parallel surfaces to be built into a lens unit at a point where the rays are convergent or divergent.

The inventor has recognized that an optimization of the lens units with respect to the spherical aberration to a degree at which the focal points are typically closer than 50 nanometers, ie closer than one tenth

pictured wavelength, lie together,

surprisingly still to others

Quality improvements of the illustration by the

leads optical assembly according to the invention.

In addition, in this embodiment, but also in other embodiments, the chromatic aberration can be corrected. This correction can be called a so-called

Correction to be infinite, i.e. so that the correction applies to every point behind the lens.

In one embodiment, the optical assembly has a common mount for the first lens unit and the second lens unit.

In one embodiment of the optical assembly, the first lens unit and the second lens unit can be displaced relative to one another parallel to a common optical axis. In particular, the first lens unit and the second lens unit can be displaced relative to one another in a range of 5 mm to 5 cm.

In this embodiment, for different

Object distances the mutual position of the two

Lens units are adjusted so that the common intermediate image plane comes to lie at a suitable distance from the two lens units.

In one embodiment of the optical assembly, the first lens unit and the second lens unit have identical characteristics.

In this embodiment, for example, two prefabricated lens units of identical design

be arranged one behind the other. This enables a particularly inexpensive and simple manufacture of the

optical assembly.

One embodiment of the optical assembly comprises three or more lens units arranged one behind the other, each pair of adjacent lens units forming an optical assembly according to the invention,

in particular wherein at least one pair of adjacent lens units forms an optical assembly according to one of the embodiments mentioned.

The basic element of the optical assembly, comprising two lens units, can be expanded in a cascade. In each stage of the cascade, a lens unit enlarges a section of the real image and projects it into a defined distance, where the next lens unit turns a section of this real image into a

projected distance and this is repeated over each level of the cascading system. The real image of the last projection lens can, for example, be made visible via a converging lens and / or an eyepiece, and the image of the object, which is now greatly enlarged and rich in detail, can be made visible via a storage medium or the eye.

This embodiment is particularly suitable for

Total magnifications in the range of 1,000 to 10,000 times.

Features of the embodiments of the optical assembly can be combined as desired, if not

contradictory .

The object is further achieved by an optical instrument according to claim 12.

The optical instrument according to the invention comprises an optical assembly according to the invention and further comprises an image sensor or an eyepiece, the image sensor or the eyepiece being arranged downstream of the second lens unit.

If an eyepiece is used, it can

resulting high-resolution image can be viewed directly by the eye. The image sensor can have, for example, light-sensitive detector elements arranged in a matrix. Such image sensors are, for example, in the form of So-called charge-coupled device sensors (CCD sensors) are commercially available.

One embodiment of the optical instrument has a perforated diaphragm arranged on the entry side of the optical assembly.

In this embodiment, the pinhole forms

virtual lens. The first stage of the optical

Instruments thus works in the manner of a pinhole camera (camera obscura), in which no setting for a specific object distance is necessary.

One embodiment of the optical instrument also has one on the entry side of the optical assembly

arranged input lens on.

The optical instrument according to this embodiment could be called a multiscope instrument. With

The same basic structure of the input lens multiprojection module eyepiece or lens multiprojection module image sensor can be used to build a universal passive optical instrument which is equally suitable for the areas of astro, telephoto, macro, micro and nano photography. The multiprojection module here is the optical one according to the invention

To understand assembly.

As a simple technical implementation of this embodiment, an arrangement consists of any input object, a projection lens, a converging lens and an eyepiece in question, the individual elements being arranged in the order mentioned along an optical axis.

In one embodiment of the optical instrument, the input lens is constructed as a telephoto lens.

This embodiment is suitable for imaging objects at a greater distance. In this embodiment, setting elements for focusing and for a zoom setting can be integrated in the telephoto lens. The subsequent optical assembly with the first and second lens elements further increase the resolution.

In one embodiment of the optical instrument, the input objective has an entry opening greater than or equal to 90 millimeters and has a focal length greater than or equal to 400 millimeters.

The invention further relates to an optical instrument, in particular a microscope, which is constructed as an optical instrument according to the invention and wherein

Input lens is constructed as a microscope lens.

This embodiment is particularly suitable for approaching the object very close to an object to be imaged.

In one embodiment of the optical instrument, in particular a microscope, the input objective has an entrance opening less than or equal to 6 millimeters and a focal length less than or equal to 10 millimeters.

In one embodiment, the optical instrument, in particular a microscope, further comprises a specimen slide and an illumination unit, starting from the

Illumination unit illuminates a light beam from the illumination unit on one side of the slide, then passes through the first and second lens units and finally strikes the image sensor, the first lens unit and second lens unit mounted on a focusing unit being able to be moved together for a maximum of 50 nanometer steps for focusing.

Features of the embodiments of the optical instrument or of the microscope can be combined as desired, if not contradictory.

The object is further achieved by a method according to claim 20.

The method according to the invention is a method for optical imaging by an optical instrument with a first lens unit and a second

Lens unit. The first lens unit converts a first image into an enlarged first real one

Intermediate picture shown. It continues with the second

Lens unit real a portion of the first Intermediate picture in an enlarged second real one

Intermediate picture shown.

The optical assembly according to the invention and the

The optical instrument or microscope according to the invention are suitable for the method according to the invention

to execute.

The optical characteristics of the first lens unit and the second lens unit can be in all

Embodiments correspond to the optical characteristics of a microscope objective. Examples are in

The following well-functioning combinations of first and second lens units are specified, each of which is characterized by its focal length f and its input aperture D in millimeters:

Example No. 1 is an embodiment in which the first and second lens units have the same characteristics. In all five tabulated examples, the input opening D of the lens units is significantly larger than the focal length f. The quotient D / f lies in the

given examples between about 3.7 (see first

Lens unit in Examples Nos. 1, 2, 4 and 5) and approx. 61 (see second lens unit in Example 5).

Exemplary embodiments of the present invention are explained in more detail below with reference to figures. Show it

Fig. 1 schematically and simplified one

optical assembly according to the invention in

perspective view;

Fig. 2 schematically and simplified one

Embodiment of an optical instrument in

Cross-section ;

Fig. 3 schematically and simplified one

Embodiment of a microscope in cross section;

Fig. 4 schematically and simplified one

Embodiment with further, in addition to the second

Lens unit arranged lens units.

FIG. 1 shows an optical assembly 100 according to the invention, comprising a first lens unit 10 and a second lens unit 20. An optical axis 4 is shown, which passes through both lens units runs through. Input side of the first

A first image plane 1 is defined for the lens unit, and there is one between the two lens units

Intermediate image plane 2 is defined and a second image plane 3 is defined on the output side of the second lens unit. The levels mentioned are imaginary levels, the position of which is determined by the optical

Imaging properties and mutual position of the first and second lens unit is defined. The first

Lens unit 10 is set up to image an image from a first image plane 1 into an enlarged real intermediate image in the intermediate image plane 2. A total of possible beam paths through the first lens unit lies in a kind of entrance cone, which is indicated by dashed lines and

intersected with the first image plane defines a first planar entrance area 11. Analogously defined one

Exit cone with possible beam paths in the

Intermediate image plane a first flat exit area 12.

The second lens unit 20 is set up to image an image from the intermediate image plane 2 into an enlarged real image in a second image plane 3.

It defines a set of possible

Beam paths through the second lens unit also a kind of entrance cone, which is indicated by dashed lines, and defined cut with the

Intermediate image plane a second flat entry area 21. Analogously, a second flat exit area 22 is defined in the second picture plane. The second Entry area 21 comprises a first part of the first exit area, which is hatched diagonally from top left to bottom right in the figure, and excludes a second part of the first exit area. The second excluded area is hatched diagonally from bottom left to top right. To illustrate the

Mapping steps have the first entry area 11 and the first exit area 12 hatched in the same way and are the second entry area 21 and the second

Exit area 22 hatched in the same way. These

Hatching does not represent any image content. Arrows on the optical axis 4 indicate the direction of the image.

Figure 2 shows a schematic cross section through an embodiment of an optical instrument. An optical assembly 100 is located in the section indicated by a curly bracket. The positions of the first image plane 1, the second image plane 3 and the

Intermediate image level 2, as well as other levels, is shown with a dashed line. The real pictures respectively. Intermediate images and excerpts from the images and intermediate images are each indicated by arrows in the respective plane, the direction of the arrow indicating the position of the image. A viewed object 60 in an object plane is imaged into the first image plane 1 by an input objective 30. A section 63 from this image 62 is through the first lens unit 10 in the

Intermediate image level 2 shown. A section 65 of the image 64 in the intermediate image plane is in turn by the second lens unit 20 imaged in the second image plane 3. The image 66 created there is imaged by a converging lens 40 into an image sensor plane 51, behind which an image sensor 50, for example a CCD sensor, is arranged.

The figure shown is not to scale. In particular, the extension of the optical elements 10, 20, 30, 40 in the direction of the optical axis 4 can be significantly larger.

The object 60 under consideration can lie, for example, at a distance of 0.5 meters up to an infinite distance. For example, the input lens 30 may have an input aperture of 90 millimeters or more. The input lens 30 can have a focal length of 400 millimeters or more, for example. The first 10 and second lens unit 20 can both be, for example

Characteristic of a microscope lens. The first 10 and second lens unit 20 can be of the same type, for example, and an input opening of 6

Have millimeters or less and have a focal length of 10 millimeters or less.

FIG. 3 shows an embodiment of a microscope 300 analogously to FIG. 2. Here, the input objective 30 is a

Microscope lens. The distance from

Object 60 to be imaged up to the input lens is small compared to the diameter of the input lens. The

For example, input lens 30 may have an input aperture of 6 millimeters or less and may have a focal length of 10 millimeters or less. The optical assembly 100, the converging lens 40 and the

Image sensor 50 can be constructed in the same way as in FIG. 2.

FIG. 4 shows an embodiment in which at least one further lens unit is arranged next to the second lens unit. There are two more in this figure

Lens units 20 'and 20' 'shown. They have the same function as the second lens unit 20, but each image a different further entry area 21 ', 21' 'onto a further exit area 22', 22 '' in a further image plane 3 ', 3' '. In the case shown, the entry area 21 'is spatially different from the

Entry areas 21 and 21 '' separately. The

Entry areas 21 and 21 ″ partially overlap. As shown in this figure, the image planes 3, 3 'and 3' 'can have different positions and orientations in space, but they can also be identical planes.

Reference character list

1 first image level

2 intermediate image level

3 second image plane

3 ', 3' 'additional image layers

4 optical axis

10 first lens unit

11 first entrance area

12 first exit area 20 second lens unit

20 ', 20' 'additional lens units

21 second entrance area

21 ', 21' 'further entry areas

22 second exit area

22 ', 22' 'further exit areas

30 input lens

40 lens

50 image sensor

51 image sensor level

60 object

61 Object level

62 real image in the first image plane

63 Part of the real image 62

64 real intermediate image in the intermediate image plane

65 part of the real intermediate image 64

66 real image in the second image plane

67 part of the real image 66

68 real image in the image sensor plane

100 optical assembly

200 optical instrument

300 microscope

Claims

1. Optical assembly (100) comprising a first

Lens unit (10) and a second lens unit (20), an intermediate image plane (2) being defined between the first lens unit and the second lens unit, the first lens unit (10) being set up to take an image of a first image plane (1) in a

to display an enlarged real intermediate image in the intermediate image plane (2) and a total of possible beam paths through the first lens unit in the first image plane form a first entry region (11)

defined and a first in the intermediate image level

Exit area (12) defined,

wherein the second lens unit (20) is set up to take an image from the intermediate image plane (2)

reproduce an enlarged real image in a second image plane (3) and a total of possible ones

Beam paths through the second lens unit in the intermediate image plane defines a second entry region (21) and in the second image plane a second

Exit area (22) defined, and

wherein the second entry region (21) comprises a first part of the first exit region and excludes a second part of the first exit region.

2. The optical assembly of claim 1, wherein the first lens unit has a first focal length and the second

Lens unit has a second focal length, the Distance from the first lens unit to the

Intermediate image plane defines a first image width, the distance from the second lens unit to the second image plane defining a second image width and a ratio of the first focal length to the first image width and / or a ratio of the second focal length to the second image width in the range 1:10 to 1: 1000 lies.

3. Optical assembly according to claim 2, wherein the

The ratio of the first focal length to the first image width and / or the ratio of the second focal length to the second image width is greater than or equal to 1:40.

4. Optical assembly according to one of claims 1 to 3, wherein the first and / or the second lens unit has a structure of an infinitely corrected lens.

5. Optical assembly according to one of claims 1 to 4, wherein the surface of the first part of the first

Exit area is a maximum of one tenth of the area of the first exit area.

6. Optical assembly according to one of claims 1 to 5, wherein at least one further lens unit is arranged next to the second lens unit and the at least one further lens unit is set up to convert an image from the intermediate image plane (2) into an enlarged real image in a further image plane (3 ', 3'') map and being a total of possible

Beam paths through the further lens unit in the intermediate image plane defines a further entry area (21 ', 21' ') and one in the further image plane

further exit area (22 ', 22' ') defined, the further entry area (21', 21 '') from the first

Entry area (21) is different.

7. Optical assembly according to one of claims 1 to 6, wherein the first lens unit (10) is designed such that the focal points formed by different radial areas of the first lens unit in the area of the intermediate image plane (2) in the direction of an optical axis of the first lens unit less are 500 nanometers apart, in particular less than 50 nanometers apart, and / or the second

Objective unit (20) is configured such that the through the different radial areas of the second

Focus points formed in the area of the second image plane (3) in the direction of an optical axis of the second lens unit are less than 500 nanometers

apart, in particular less than 50 nanometers apart.

8. Optical assembly according to one of claims 1 to 7, wherein the optical assembly has a common socket for the first lens unit (10) and the second

Has lens unit (20).

9. Optical assembly according to one of claims 1 to 8, wherein the first lens unit (10) and the second

Lens unit (20) parallel to a common one

optical axis (4) are mutually displaceable, in particular in a range of 5mm to 5cm are mutually displaceable.

10. Optical assembly according to one of claims 1 to 9, wherein the first lens unit (10) and the second

Objective unit (20) have identical characteristics.

11. Optical assembly according to one of claims 1 to 10, wherein the optical assembly comprises three or more lens units (10, 20) arranged one behind the other and wherein a pair of adjacent lens units (10, 20) each have an assembly according to one of claims 1 to 10 forms.

12. Optical instrument (200, 300) comprising one

Optical assembly according to one of claims 1 to 11, wherein the optical instrument further comprises an image sensor (50) or an eyepiece and wherein the image sensor or the eyepiece is arranged downstream of the second lens unit.

13. The optical instrument according to claim 12, wherein the optical instrument further comprises a pinhole arranged on the entry side of the optical assembly.

14. An optical instrument (200, 300) according to claim 12, wherein the optical instrument further on the

Arranged side of the optical assembly

Has input lens (30).

15. Optical instrument (200) according to claim 14, wherein the input lens (30) is constructed as a telephoto lens.

16. Optical instrument (200) according to claim 14 or 15, wherein the input lens has an entry opening greater than or equal to 90 millimeters and a focal length greater than or equal to 400 millimeters.

17. Optical instrument according to claim 14, wherein the input objective is constructed as a microscope objective.

18. Optical instrument according to claim 14 or 17, wherein the input lens has an entrance opening less than or equal to 6 millimeters and has a focal length less than or equal to 10 millimeters.

19. Optical instrument according to one of claims 17 or 18, wherein the optical instrument further comprises a specimen slide and a lighting unit, wherein, starting from the lighting unit, a light beam

Illumination unit one side of the slide illuminated, then passes through the first and second lens units and finally strikes the image sensor, the first mounted on a focusing unit

Lens unit and second lens unit for focusing together in steps of a maximum of 50 nanometers

are movable.

20. Method for optical imaging by an optical instrument with a first lens unit and a second lens unit, with the first

Lens unit a first image is mapped into an enlarged first real intermediate image and with the second lens unit a partial area of the first real intermediate image into an enlarged second real one

Intermediate picture is mapped.