DE102024206242A1 - Infinity corrected microscope objective for scanning applications - Google Patents

Abstract

An infinitely corrected microscope objective (2) for scanning applications has a high imaging quality over the entire field of view and a small number of lenses depending on the etendue (G), such that it has a first etendue (G1) in the range from 0.8 mm2 to 1.8 mm2 and a maximum of nine lenses (Li; 1 ≤ i ≤ 9) or that it has a second etendue (G2) in the range of more than 1.8 mm2 and a maximum of 15 lenses (Li; 1 ≤ i ≤ 15).

Description

The invention relates to an infinitely corrected microscope objective for scanning applications. The invention also relates to an optical assembly and a microscope with such an objective. Finally, the invention relates to a use of a corresponding objective and a method for automated scanning of a sample.

Depending on the application, microscope lenses must meet different requirements.

Microscope objectives with a high light conductivity (etendue) are known from the state of the art.

US 2019 - 0324246 , US 9746658 and US 8350904 concern dry lenses with high light conductivity. US 9939622 , US 8988780 , JP 2011075982 and DE 102011109783 concern immersion lenses with high light conductivity.

On the one hand, these lenses are very complex, but on the other hand, the image quality drops off significantly towards the edges.

One object of the invention is to improve a microscope objective. A particular object is to provide an infinitely corrected microscope objective with a simplified structure and improved optical properties.

This object is achieved by a microscope objective according to the present invention.

According to a first aspect, the lens may have an etendue in the range of 0.8 mm ² to 1.8 mm ² and a maximum of 9 lenses. It may also have an etendue in the range of more than 1.8 mm ² and a maximum of 15 lenses. In this case, the etendue may in particular be smaller than 5.1 mm ² .

In particular, the lenses may exhibit vignetting of less than 5%.

In particular, they can be apochromatically corrected over a spectral bandwidth of at least 200 nm, in particular in the range from 400 nm to 800 nm. In particular, they can be apochromatically corrected over a spectral bandwidth of at least 200 nm, in particular in the range from 400 nm to 700 nm. In particular, they can be apochromatically corrected in the range from 460 nm to 660 nm.

They may preferably have a numerical aperture of at least 0.9.

The lenses according to the invention can be produced particularly cost-effectively. This nevertheless leads to a high level of robustness of the optical system.

According to a further aspect, the lenses according to the invention can have a Strehl ratio of at least 0.8, in particular at least 0.9, despite their reduced complexity.

In particular, they can have such a high Strehl ratio over at least 50%, in particular at least 70%, in particular at least 90%, in particular at least 95% of the field of view, in particular over the entire field of view.

They can have such a high Strehl ratio in particular over a partial area of the field of view with an area of at least 1 mm ² .

This ensures high resolution over large areas of the field of view, especially over the entire field of view. This makes it easier to combine a number of partially overlapping images into a mosaic image.

The visual field is also called the object field.

According to the invention, it was recognized that it is an advantage, particularly for scanning applications in which large, especially large-area samples are examined, if the microscope lenses used for this have a large field of view and at the same time offer a high resolution over the entire field of view. The Strehl ratio can be used to characterize the resolution. For the lenses according to the invention, this can be at least 0.8, in particular at least 0.83, in particular at least 0.89, in particular at least 0.9, in particular over the entire field of view.

Especially for scanning applications, it may be necessary to capture a large number of images and then assemble them into a mosaic image. This is preferably done automatically.

For high throughput, the total time required to capture each image is a critical factor. This time depends on the time required to capture a single image and the number of images to be captured. It is always desirable to reduce the overall time required to capture each image. This leads to faster results and increased throughput. In general, this leads to lower costs.

An important factor that influences the total time required to capture the individual images - in addition to the capture time for a single image - is the field of view size of the optical system. A larger field of view size allows larger areas to be captured in individual images. This means that fewer individual images are needed to image an extended sample. This leads to a reduced scanning time and a reduction in the effort required to assemble the images into a mosaic image.

However, when increasing the field of view size, it is critically important that the lens has a high resolution for all relevant wavelength ranges across the entire field of view. This requirement of high resolution with a large field of view corresponds to an increase, in particular a maximization, of the light conductance (etendue). The etendue is proportional to the square of the linear dimension, in particular the diameter, of the field of view. It is also proportional to the square of the numerical aperture (NA).

At the same time, it may be desirable, especially for routine applications, to reduce the complexity of the microscope objective. This can lead in particular to cost savings. Reduced complexity is understood in particular to mean a reduction in the number of optical elements required, in particular lenses. Preferably, the number of aspherical lenses is reduced in particular. It has been shown that this has led to considerable cost savings.

Finally, it can be advantageous for many applications if lenses with different properties, especially with different magnifications, can be used interchangeably. This makes it possible, for example, to first take an overview image with a relatively lower resolution. The overview image can be used to record regions of interest (ROI). These can then be examined in detail with a high-resolution lens.

To simplify the exchange of lenses and to ensure compatibility with standard microscope stands, it is advantageous if the lens is infinity corrected. This means that it is designed for infinity optics. In this case, the imaging light leaves the lens as a parallel beam. This enables the use of a tube of any length.

According to the invention, it was further recognized that the complexity of the lenses generally increases with increasing light conductance. The lens can therefore have a number of lenses that depends on the etendue (G).

Lenses according to the invention have a significantly reduced complexity, in particular a smaller number of lenses for a given light conductance value. They can nevertheless ensure a high resolution across the entire field of view, in particular due to their high Strehl ratio.

The lenses with a maximum of nine lenses can have an object field height, i.e. half an object field diameter, of more than 0.3 mm.

The lenses with a maximum of 15 lenses can have an object field height, i.e. half an object field diameter, of more than 0.6 mm.

The vignetting may not exceed 5%, in particular not exceed 3%.

In the case of a lens with 9 lenses, these can be arranged in 6 subgroups. These can be, for example, 3 single lenses and 3 double cemented elements.

In the case of a lens with a maximum of 15 lenses, these can be arranged in 8 or 9 subgroups. The subgroups can comprise 2 triple cemented elements, 3 double cemented elements and 3 single lenses, or 2 triple cemented elements, 2 double cemented elements and 5 single lenses.

With such arrangements of lenses, particularly advantageous optical properties could be achieved.

According to one aspect, the lens can be designed as a dry lens. It can have a numerical aperture (NA) in the range of 0.9-1.0. This leads to a particularly high resolution.

According to a further aspect, the lens can be designed as an immersion lens. It can have a numerical aperture (NA) of at least 1.0, in particular at least 1.1. This leads to a particularly high resolution of the lens.

According to a further aspect, the lens can be designed completely without aspherical lenses. This further reduces the complexity of the lens. This leads in particular to a reduction in costs.

In the case of 9 lenses, these must be made of at least 5, in particular at least 6, in particular at least 7, in particular at least 8 different types of glass.

In the case of a lens with a maximum of 15 lenses, these can be made of at least 8, in particular at least 10, in particular at least 12 different types of glass.

It has been shown that particularly good optical properties of the lens can be achieved by a suitable selection of different types of glass.

According to a further aspect, the second lens group of the objective may comprise two cemented elements.

For a lens with an etendue of less than 1.8 ^mm2, these may be double cemented elements.

For a lens with a clearance of more than 1.8 mm ^2, these may be triple cemented elements.

According to a further aspect, the lens can be apochromatically corrected over a bandwidth of at least 200 nm, in particular in a wavelength range between 400 nm and 800 nm, in particular in the range from 400 nm to 700 nm, in particular in the range from 460 nm to 660 nm. It has been shown that by reducing the bandwidth over which the lens is apochromatically corrected, the number of lenses required can be reduced.

Apochromatically corrected means that the maximum deviation of the focus position within the spectrum with respect to the reference wavelength lies within the depth of field.

According to a further aspect, the third lens group can have three subgroups (G31, G32 and G33). The first subgroup (G31) can have a positive refractive power. The second subgroup (G32) can have a negative refractive power. The third subgroup (G33) can have a negative refractive power.

Here and in the following, the order of the optical elements of the lens is given in the direction from the object field to the image field. In relation to the lens, "front" refers to the side facing the object field and "back" refers to the side facing away from the object field.

Further possible details of the lens are described below.

wobei d den Abstand vom Deckglas zum Rand der vordersten Linsenfläche des Objektivs angibt und L den Gesamt-Abstand zwischen dem Objektfeld und dem Scheitel der in Strahlrichtung hintersten Linsenoberfläche des Objektivs.The lens can have a relatively short working distance. In particular, the following can apply: $$\text{d:L}<\mathrm{4,9}\times {10}^{-3}$$

where d is the distance from the cover glass to the edge of the front lens surface of the objective and L is the total distance between the object field and the vertex of the rearmost lens surface of the objective in the beam direction.

wobei d0 den Abstand vom Objektfeld zum Scheitel der vordersten Linsenoberfläche des Objektivs angibt.The working distance of the lens can also meet the following conditions: $$\text{d0:L}<9\times {10}^{-3},$$

where d0 is the distance from the object field to the vertex of the front lens surface of the objective.

If the greatest distance of light rays emanating from an object on the optical axis to the optical axis in the three subgroups G31, G32 and G33 of the third lens group G3 is designated as h1, h2 and h3, these quantities can in particular satisfy the following inequalities: $$\begin{array}{l}\mathrm{1,1}<\text{h1:h2}<\mathrm{1,8}\text{ und/<figure-callout id="1" label="oder" filenames="DE102024206242A1\_0011.png,DE102024206242A1\_0015.png" state="{{state}}"><figure-callout id="2" label="oder" filenames="DE102024206242A1\_0011.png,DE102024206242A1\_0015.png" state="{{state}}">oder</figure-callout></figure-callout>}\\ \text{1}\text{,2}<\text{h2:h3}<\mathrm{1,6.}\end{array}$$

In a lens with a maximum of 9 lenses, the third lens group G3 can have a first lens with positive refractive power and a second lens with negative refractive power.

Together with a tube lens unit, in particular with a tube lens with a focal length of 200 mm or with a focal length of 164.5 mm, the microscope objective according to the preceding description can form an optical assembly.

A further object of the invention is to improve a microscope, in particular for scanning applications, in particular for optical mapping.

This task is solved by a microscope with an objective as described above. The advantages arise from those described above.

The microscope can have an automated scanning device. The scanning device can enable a one-dimensional (linear) displacement of the sample, a two-dimensional displacement of the sample or a three-dimensional displacement of the sample. In addition to linear displacements, the scanning device can also have one, two or three rotational degrees of freedom. This allows the samples to be arranged, and in particular moved, very flexibly.

The scanning device can comprise an image capture device, in particular a digital image capture device, in particular a digital camera.

The scanning device can have an image processing device. This can in particular enable automated processing. This makes it easier, in particular, to stitch individual images together to form a mosaic image.

The microscope objectives described above are particularly advantageous for use in scanning applications, especially for optical mapping. They facilitate automated scanning of large, particularly large-area, samples.

• - Bereitstellen eines Mikroskops gemäß der vorhergehenden Beschreibung,
• - Bereitstellen einer zu untersuchenden Probe,
• - Aufnahme mindestens zweier Bilder unterschiedlicher Ausschnitte der Probe, wobei die Ausschnitte einen Überlappungsbereich aufweisen und
• - Zusammensetzen der Bilder zu einem Mosaik-Bild.

A further object of the invention is to improve a method for automated scanning of a sample. This object is achieved by a method with the following steps:

• - Providing a microscope according to the previous description,
• - Providing a sample to be examined,
• - taking at least two images of different sections of the sample, with the sections having an overlapping area and
• - Putting the pictures together to form a mosaic image.

The method can in particular be an optical mapping method.

Before the images are assembled, they can be analyzed and/or processed using an image processing algorithm. This can simplify and/or improve the assembly of the images.

It is also possible to analyze and/or edit the composite mosaic image after the images have been assembled using an image processing algorithm. This can further improve the quality.

To take pictures of different sections of the sample, it can be moved linearly, two-dimensionally or three-dimensionally. In particular, it can be moved step by step.

The movement of the sample and the acquisition of successive images of different sections of the sample can be carried out in an automated manner.

• 1 schematisch den Aufbau eines Mikroskops,
• 2 einen schematischen Längsschnitt durch die optischen Bauelemente des Mikroskop-Objektivs gemäß einer ersten Variante (E1),
• 3 einen schematischen Längsschnitt durch die optischen Bauelemente des Mikroskop-Objektivs gemäß einer zweiten Variante (E2),
• 4 einen schematischen Längsschnitt durch die optischen Bauelemente des Mikroskop-Objektivs gemäß einer dritten Variante (E3),
• 5 eine Gegenüberstellung der Objektfeldhöhe (h_obj) und der numerischen Apertur der drei Objektive gemäß den Varianten E1, E2 und E3,
• 6-8 schematisch den Verlauf des Strehl-Verhältnisses über das Gesichtsfeld bei Licht unterschiedlicher Wellenlängen und
• 9-11 schematisch den Verlauf einer Intensität der Auflichtbeleuchtung über das Gesichtsfeld der drei Objektive gemäß den Varianten E1, E2 und E3.

Other details of the invention emerge from the description of embodiments based on the figures. They show:

• 1 schematically the structure of a microscope,
• 2 a schematic longitudinal section through the optical components of the microscope objective according to a first variant (E1),
• 3 a schematic longitudinal section through the optical components of the microscope objective according to a second variant (E2),
• 4 a schematic longitudinal section through the optical components of the microscope objective according to a third variant (E3),
• 5 a comparison of the object field height (h _obj ) and the numerical aperture of the three lenses according to the variants E1, E2 and E3,
• 6-8 schematically the course of the Strehl ratio over the field of view for light of different wavelengths and
• 9-11 schematically the course of an intensity of the incident light illumination over the field of view of the three objectives according to the variants E1, E2 and E3.

In the 1 The basic structure of a microscope 1 is shown as an example and schematically. The representation is to be understood as an example and not as restrictive.

The microscope 1 has an infinite optic. This means that the beam path 3 runs parallel behind the lens 2. The area between the lens 2 and a tube lens 5 of a tube lens unit 6 is also referred to as the infinite space 4. An intermediate image is generated in an intermediate image plane 7 by means of the tube lens unit 6. The intermediate image can be viewed using an eyepiece 8. It can also be directed to an image capture device, in particular in the form of a camera 9. The camera 9 can in particular be a digital camera.

An example is shown in the 1 also a lighting device 10. The lighting device 10 has a radiation source unit 11. A laser can serve as the radiation source unit 11.

The illumination device 10 can also have a beam splitter 12. With the help of the beam splitter 12, the illumination radiation 3 can be guided through the objective 2 to a sample 13 to be observed.

The one in the 1 The schematically illustrated beam path is particularly suitable for epi-fluorescence systems. The illumination can be designed as Köhler illumination. Critical illumination is also possible. Instead of the beam splitter 12, a prism, in particular a cubic prism, can also be provided. Alternative variants for coupling in the illumination radiation are known from the prior art.

Also shown schematically is the 1 a scanning device 14. The scanning device 14 has one or more displacement devices 15. With the help of the displacement devices 15, the sample 13 can be displaced relative to the beam path 3 in the microscope 1, in particular relative to the objective 2.

To clarify the working distance of lens 2, the 1 The distance d from the cover glass 16 to the outer edge of the front lens surface 17 of the objective 2 is shown as an example.

The distance from an object plane 18 to the vertex 19 of the front lens surface 17 is shown as d0.

L denotes the total distance between the object plane 18 and the vertex 19 of the rearmost lens surface of the objective 2 in the beam direction. The latter is in the 1 not explicitly shown.

The microscope 1 can have a footprint with a width b of not more than 250 mm, in particular not more than 205 mm.

2 shows a longitudinal section through the arrangement of the optical components of the lens 2.

All variants (E1, E2 and E3) are suitable for use with cover glasses 16 with a thickness of 0.17 mm, a refractive index of nd=1.523 and the Abbe number vd=54.52 (related to a d-line of 587.562 nm).

In the 2 to 4 The course of a central main ray HS and two marginal rays RS1, RS2 is shown as an example.

For reasons of clarity, mechanical components of the lens 2 are not shown in the figures.

In the 2 , 3 and 4 The cover glass (DG) 16 is also shown.

Lens 2 is specifically an apochromatic lens 2.

In the 2 The variant shown (E1) is in particular a dry lens.

The lens 2 according to 2 has 9 lenses L1 to L9.

The optical design data of lens 2 according to 2 are summarized in Table 1. Table 1: optical design data of lens 2 according to Fig. 2: Surface No. r (mm) d (mm) nd vd 1 -16,730 15,067 1,804 46.50 2 9,846 4,663 1,717 29.62 3 -59,780 4,416 4 Infinity 0.154 5 13,962 9,317 1,439 94.95 6 -13,757 2,902 1,691 54.71 7 -22,985 1,525 8 18,606 5,402 1,569 71.34 9 -13,522 1,000 2,003 28.27 10 45,162 0.673 11 15,918 3,165 1,569 71.34 12 66,860 0.354 13 9,509 4,089 1,592 68.37 14 12,624 0.130 15 5,477 6,684 1,883 40.76 16 4,311 0.288

The information on the refractive index (nd) and the Abbe number (vd) refer to the d-line (587.562 nm).

• Vergrößerung: 40 fach $$\text{NA:0}\text{,95}$$
  
  $$\text{L:60}\text{,00 mm}$$
  
  $$\text{d:0}\text{,150 mm}$$
  
  $$\text{d0:0}\text{,288 mm}$$
  
  $$\text{d:L}=\mathrm{2,5}\times {10}^{-3}$$
  
  $$\text{d0:L}=\mathrm{4,8}\times {10}^{-3}$$
  
  $$\begin{array}{l}{\text{h}}_{\text{obj}}:\mathrm{0,3125}\text{ mm}\\ \text{G}=\mathrm{0,8699}{\text{ <figure-callout id="2" label="mm" filenames="DE102024206242A1\_0011.png,DE102024206242A1\_0015.png" state="{{state}}">mm</figure-callout>}}^2\end{array}$$
  

Further data of lens 2:

• Magnification: 40x $$\text{NA:0}\text{,95}$$
  
  $$\text{L:60}\text{,00 mm}$$
  
  $$\text{d:0}\text{,150 mm}$$
  
  $$\text{d0:0}\text{,288 mm}$$
  
  $$\text{d:L}=\mathrm{2,5}\times {10}^{-3}$$
  
  $$\text{d0:L}=\mathrm{4,8}\times {10}^{-3}$$
  
  $$\begin{array}{l}{\text{h}}_{\text{obj}}:\mathrm{0,3125}\text{ mm}\\ \text{G}=\mathrm{0,8699}{\text{ mm}}^2\end{array}$$
  

The lens 2 is suitable for use with a tube lens 5 with a focal length of 200 mm.

The lens 2 has three lens groups G1, G2 and G3. The first lens group G1 has a positive refractive power. It includes the lenses L1, L2 and L3.

The second lens group G2 has a positive refractive power. The second lens group G2 includes the lenses L4, L5, L6 and L7.

The lenses L4 and L5 form a double cemented element.

The lenses L6 and L7 form a double cemented element.

The third lens group G3 has a negative refractive power.

The third lens group G3 includes the lenses L8 and L9.

The lenses L8 and L9 form a double cemented element. The lens L8 is also known as optical element OE31. It has a positive refractive power.

The lens L9 is also known as optical element OE32. It has a negative refractive power.

The 2 The lens 2 shown has an etendue of G = 0.8699 mm ² .

In the 3 a second variant (E2) of a lens 2 is shown.

The lens 2 according to 3 has 15 lenses L1 to L15.

The first lens group G1 includes the lenses L1 to L4.

The second lens group G2 includes the lenses L5 to L10.

The lenses L5 to L7 form a triple cemented element.

The lenses L8 to L10 form a triple cemented element.

The third lens group G3 has the lenses L11 to L15.

The lens L11 forms the subgroup G31.

The lenses L12 and L13 of the subgroup G32 form a double cemented element.

The lenses L14 and L15 of the subgroup G33 form a double cemented element.

The lens 2 according to 3 has an etendue G = 3.4799 mm ² .

For lens 2 according to 3 It is a dry lens.

The optical design data of lens 2 according to 3 are summarized in Table 2. Table 2: optical design data of lens 2 according to Fig. 3: Surface No. r (mm) d (mm) nd vd 1 142,661 1,000 1,855 24.80 2 28,105 1,000 1,883 40.76 3 17,981 3,915 4 -26,827 4,524 1,847 23.78 5 -38,436 3,193 1,883 40.76 6 -40,831 0.622 7 48,267 18,410 1,855 24.80 8 -169,890 0.100 9 85,109 10,276 1,592 68.37 10 -17,345 7,048 1,651 55.89 11 98,636 11,441 1,456 90.90 12 -52,386 1,652 13 41,646 7,455 1,439 94.95 14 -35,234 1,000 1,638 42.41 15 17,276 11,139 1,592 68.37 16 -80,941 0.226 17 22,295 7,149 1,618 63.39 18 36,105 0.154 19 13,395 3,409 1,497 81.55 20 16,175 2,613 21 9,008 7,079 1,456 90.90 22 22,142 0.205 23 7,450 3,319 1,816 46.62 24 5,590 0.894

The information on the refractive index (nd) and the Abbe number (vd) refer to the d-line (587.562 nm).

• Vergrößerung: 20 fach
• NA: 0,95
• L: 107,99 mm
• d: 0,411 mm
• d0: 0,894 mm
• d:L = 3,8 x 10^-3
• d0:L = 8,3 x 10^-3
• h_obj: 0,625 mm
• G = 3,4799 mm²

Further data of lens 2 according to 3 :

• Magnification: 20x
• NA: 0.95
• L: 107.99 mm
• d: 0.411 mm
• d0: 0.894 mm
• d:L = 3.8 x 10 ^-3
• d0:L = 8.3 x 10 ^-3
• h _obj : 0.625 mm
• G = 3.4799 mm²

The lens 2 is suitable for use with a tube lens 5 with a focal length of 164.5 mm.

• h1 = 14,36 mm,
• h2 = 11,00 mm,
• h3 = 7,71 mm und damit
• h1 : h2 = 1,305 und
• h2 : h3 = 1,427.

If the greatest distance of light rays emanating from an object on the optical axis to the optical axis in the three subgroups G31, G32 and G33 of the third lens group G3 is designated with h1, h2 and h3, then:

• h1 = 14.36 mm,
• h2 = 11.00 mm,
• h3 = 7.71 mm and thus
• h1 : h2 = 1.305 and
• h2 : h3 = 1.427.

In the 4 Another variant (E3) of lens 2 is shown.

For lens 2 according to 4 It is a water immersion lens.

The optical design data of lens 2 according to 4 are summarized in Table 3. Table 3: optical design data of lens 2 according to Fig. 4: Surface No. r (mm) d (mm) nd vd 1 -44,873 1,000 1,581 40.75 2 14,040 25,000 1,613 44.49 3 22,604 6,243 4 -42,712 6,106 1,589 61.27 5 -18,702 1,669 1,673 38.26 6 -42,806 0.631 7 88,252 8,081 1,847 23.78 8 -142,575 10,312 9 77,638 25,000 1,637 42.41 10 45,052 17,776 1,439 94.95 11 -26,083 10,845 1,713 53.83 12 -37,642 4,540 13 60,618 8,938 1,439 94.95 14 -46,368 2,138 1,637 42.41 15 24,348 9,896 1,592 68.37 16 -205,611 0.544 17 25,823 13,153 1,487 84.47 18 73,714 0.664 19 13,538 7,990 1,456 90.90 20 25,889 0.100 21 8,331 6,725 1,883 40.76 22 2,084 1,957 1,459 67.82 23 Infinity 0.302 1,333 55.80

The information on the refractive index (nd) and the Abbe number (vd) refer to the d-line (587.562 nm).

• Vergrößerung: 20 fach
  • NA: 1,0 (Wasser-Immersion)
  • L: 169,78 mm
  • d: 0,302 mm
  • d0: 0,302 mm
  • d:L = 1,8 x 10-3
  • d0:L = 1,8 x 10-3
  • hobj: 0,625 mm
  • G = 4,6649 mm²

Further data of lens 2 according to 4 :

• Magnification: 20x
  • NA: 1.0 (water immersion)
  • L: 169.78 mm
  • d: 0.302 mm
  • d0: 0.302 mm
  • d:L = 1.8 x 10-3
  • d0:L = 1.8 x 10-3
  • hobj: 0.625 mm
  • G = 4.6649 mm ²

The lens 2 is suitable for use with a tube lens 5 with a focal length of 164.5 mm.

The lens 2 (E3) according to 4 has an etendue G = 4.6649 mm ² .

• h1 = 16,55 mm,
• h2 = 13,78 mm,
• h3 = 9,79 mm

und damit

• h1 : h2 = 1,301 und
• h2 : h3 = 1,408

If the greatest distance of light rays emanating from an object on the optical axis to the optical axis in the three subgroups G31, G32 and G33 of the third lens group G3 is designated with h1, h2 and h3, then:

• h1 = 16.55 mm,
• h2 = 13.78 mm,
• h3 = 9.79 mm

and thus

• h1 : h2 = 1.301 and
• h2 : h3 = 1.408

In the 5 The field heights (hobj), ie half the field diameter in relation to the numerical aperture (NA) of the objectives (E1, E2, and E3) are shown schematically. 5 the curves for an etendue G = 0.8 mm ² , G = 1.8 mm ² and G = 5.1 mm ² are shown. Objectives 2 with a numerical aperture of at least 1 form immersion objectives. Objectives with a numerical aperture NA < 1 can be designed as dry objectives. Accordingly, three different areas of the etendue are distinguished in the figure. These are designated as "Level 1", "Level 2" and "Level 3" as examples.

In the 6-8 The Strehl ratios of the three lenses 2 are according to the 2 , 3 and 4 each for light with a wavelength λ1 = 460 nm, λ2 = 546 nm and λ3 = 660 nm.

As can be seen from the figures, the Strehl ratio over the entire field of view is greater than 0.8. For individual wavelengths or a limited wavelength range, the Strehl ratio over the entire field of view is even greater, in particular greater than 0.83, in particular greater than 0.9.

In the 9-11 To illustrate the marginal light fall-off, the relative illumination intensity at a wavelength of 546.074 nm is shown across the field of view.

As can be seen from the figures, the lenses 2 lead to a homogeneous illumination of the field of view with a small amount of vignetting when used with incident light.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• US 2019 - 0324246 [0004]
• US 9746658 [0004]
• US 8350904 [0004]
• US 9939622 [0004]
• US 8988780 [0004]
• JP 2011075982 [0004]
• DE 102011109783 [0004]

Claims (15)

Infinity corrected microscope objective (2) for scanning applications comprising 1.1. a first lens group (G1) with positive refractive power, 1.2. a second lens group (G2) with positive refractive power and 1.3. a third lens group (G3) with negative refractive power, 1.4. wherein the microscope objective (2) 1.4.1. has a numerical aperture (NA) of at least 0.9, 1.4.2. has less than 5% vignetting, 1.4.3. is apochromatically corrected over a spectral bandwidth of at least 200 nm and 1.4.4. has a small number of lenses dependent on the etendue (G), such that 1.4.4.1. that it has a first etendue (G1) in the range from 0.8 mm ² to 1.8 mm ² and a maximum of nine lenses (Li; 1 ≤ i ≤ 9) or 1.4.4.2. that it has a second etendue (G2) in the range of more than 1.8 mm ² and a maximum of 15 lenses (Li; 1 ≤ i ≤ 15). Microscope objective (2) according to claim 1 , characterized in that it is designed as a dry objective and has a numerical aperture (NA) in the range from 0.9 to 1.0. Microscope objective (2) according to claim 1 , characterized in that it is designed as an immersion objective and has a numerical aperture (NA) of at least 1.0. Microscope objective (2) according to one of the preceding claims, characterized in that it has a Strehl ratio of at least 0.8 over at least 70% of the field of view. Microscope objective (2) according to one of the preceding claims, characterized in that it has no aspherical lenses. Microscope objective (2) according to one of the preceding claims, characterized in that the second lens group (G2) has two cemented elements (G21, G22). Microscope objective (2) according to one of the preceding claims, characterized in that it is apochromatically corrected over a bandwidth of at least 200 nm in a wavelength range between 400 nm and 800 nm. Microscope objective (2) according to one of the preceding claims, characterized in that the third lens group (G3) has three subgroups (G31, G32 and G33), wherein the first subgroup (G31) has a positive refractive power, the second subgroup (G32) has a negative refractive power and the third subgroup (G33) has a negative refractive power. Microscope objective (2) according to one of the preceding claims characterized by the following optical design data: Surface No. r (mm) d (mm) nd vd 1 -16,730 15,067 1,804 46.50 2 9,846 4,663 1,717 29.62 3 -59,780 4,416 4 Infinity 0.154 5 13,962 9,317 1,439 94.95 6 -13,757 2,902 1,691 54.71 7 -22,985 1,525 8 18,606 5,402 1,569 71.34 9 -13,522 1,000 2,003 28.27 10 45,162 0.673 11 15,918 3,165 1,569 71.34 12 66,860 0.354 13 9,509 4,089 1,592 68.37 14 12,624 0.130 15 5,477 6,684 1,883 40.76 16 4,311 0.288 Microscope objective (2) according to one of the Claims 1 until 8 characterized by the following optical design data: Surface No. r (mm) d (mm) nd vd 1 142,661 1,000 1,855 24.80 2 28,105 1,000 1,883 40.76 3 17,981 3,915 4 -26,827 4,524 1,847 23.78 5 -38,436 3,193 1,883 40.76 6 -40,831 0.622 7 48,267 18,410 1,855 24.80 8 -169,890 0.100 9 85,109 10,276 1,592 68.37 10 -17,345 7,048 1,651 55.89 11 98,636 11,441 1,456 90.90 12 -52,386 1,652 13 41,646 7,455 1,439 94.95 14 -35,234 1,000 1,638 42.41 15 17,276 11,139 1,592 68.37 16 -80,941 0.226 17 22,295 7,149 1,618 63.39 18 36,105 0.154 19 13,395 3,409 1,497 81.55 20 16,175 2,613 21 9,008 7,079 1,456 90.90 22 22,142 0.205 23 7,450 3,319 1,816 46.62 24 5,590 0.894 Microscope objective (2) according to one of the Claims 1 until 8 characterized by the following optical design data: Surface No. r (mm) d (mm) nd vd 1 -44,873 1,000 1,581 40.75 2 14,040 25,000 1,613 44.49 3 22,604 6,243 4 -42,712 6,106 1,589 61.27 5 -18,702 1,669 1,673 38.26 6 -42,806 0.631 7 88,252 8,081 1,847 23.78 8 -142,575 10,312 9 77,638 25,000 1,637 42.41 10 45,052 17,776 1,439 94.95 11 -26,083 10,845 1,713 53.83 12 -37,642 4,540 13 60,618 8,938 1,439 94.95 14 -46,368 2,138 1,637 42.41 15 24,348 9,896 1,592 68.37 16 -205,611 0.544 17 25,823 13,153 1,487 84.47 18 73,714 0.664 19 13,538 7,990 1,456 90.90 20 25,889 0.100 21 8,331 6,725 1,883 40.76 22 2,084 1,957 1,459 67.82 23 Infinity 0.302 1,333 55.80 Optical assembly comprising 12.1. a microscope objective (2) according to one of the preceding claims and 12.2. a tube lens unit (6) with a tube lens (5) with a focal length of 200 mm or 164.5 mm. Microscope (1) with a microscope objective (2) according to one of the Claims 1 until 11 . Microscope (1) according to claim 13 , characterized by an automated scanning device (14). Method for automated scanning of a sample comprising the following steps: 15.1. Providing a microscope (1) according to one of the Claims 13 until 14 , 15.2. Providing a sample to be examined, 15.3. Taking at least two images of different sections of the sample, whereby the sections have an overlapping area, 15.4. Combining the images to form a mosaic image.

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