阅读说明：本技术 用于角度可变照明的照明模块 (Lighting module for angle-variable lighting ) 是由 克里斯蒂安·迪特里希 拉尔斯·斯托普 布莱斯·安东·莫法特 于 2020-11-13 设计创作，主要内容包括：本发明的各种示例涉及一种显微镜装置(90),其包括具有入射光瞳平面的物镜(112),并且包括具有多个光源(121、421-422、425、621-631)的照明模块(111),这些光源布置成相互之间间隔一定距离,并且被配置为发光。在一些示例中,提供了漫射滤光器(409)。该漫射滤光器(409)布置在与入射光瞳平面共轭的平面(700)中。作为替代或补充,还可以使用光波导(481-486),其将来自所述光源的光引导到所述共轭平面。(Various examples of the invention relate to a microscope arrangement (90) comprising an objective (112) with an entrance pupil plane and comprising an illumination module (111) with a plurality of light sources (121, 421 and 422, 425, 621 and 631) which are arranged at a distance from one another and are configured to emit light. In some examples, a diffusive filter (409) is provided. The diffusive filter (409) is arranged in a plane (700) conjugate to the entrance pupil plane. Alternatively or additionally, an optical waveguide (481-.)

1. Microscope device (90), characterized in that it comprises:

an objective lens (112) having an entrance pupil plane,

a lighting module (111) comprising a plurality of light sources (121, 421-

The diffusive filter (409) arranged in a plane (700) conjugate to the entrance pupil plane.

2. The microscope device (90) as claimed in claim 1, wherein the light guide (400) is embodied at least partially as a cavity between reflective partition walls (401-403).

3. The microscope device (90) according to claim 1 or 2, wherein the light guide (481-486) is at least partially embodied as an optical fiber (481-486).

4. The microscope device (90) according to one of claims 1 to 3, wherein the diffusion filter (409) is embodied as a diffuser plate (409).

5. The microscope device (90) according to claim 4,

wherein the plurality of light guides (400, 481-,

wherein the plurality of light guides (400, 481-,

wherein the second region (701) is larger than the first region (701).

6. The microscope device (90) according to claim 4 or 5,

wherein the plurality of light guides (400, 481-486) and/or the plurality of further light sources (621-631) are at least partially arranged such that the respective light is coupled to the diffuser plate (409) through a circumferential side (409C) of the diffuser plate (409).

7. The microscope device (90) according to any one of claims 1 to 6, wherein the diffusive filter (409) comprises a fluorescent material.

8. The microscope device (90) according to any one of claims 1 to 7, wherein a plurality of light sources (121, 421) having different luminescence spectra are respectively assigned to at least one light guide (400, 481-486) of the plurality of light guides (400, 481-486).

9. The microscope device (90) according to any one of claims 1 to 8, wherein the diffuser plate (409) comprises reflective structures (601) extending in a lateral direction.

10. The microscope device according to any one of claims 1 to 9, further comprising:

an actuator configured to position or deform at least one light guide (400, 481-.

11. Microscope device (90), characterized in that it comprises:

an objective lens (112) having an entrance pupil plane,

an illumination module (111) comprising a plurality of light sources (121, 421-,

wherein the light guide (400, 481-486) is configured to facilitate cross-coupling of light.

12. The microscope device (90) according to any one of claims 1 to 11, further comprising:

a control unit (115) configured to drive different light sources (121, 421-: autofocus, digital contrast, and bright field microscopy.

13. Method for controlling a microscope device (90) comprising an objective lens (112), wherein the method comprises:

selecting an operation mode of the microscope device (90) from a plurality of operation modes, an

Driving a plurality of light sources (121, 421-;

wherein an operating mode of the plurality of operating modes comprises one or more of: autofocus, digital contrast, and bright field microscopy.

14. The method of claim 13, wherein the plurality of light sources (121, 421-.

15. The method according to claim 14, wherein the selected reference illumination pattern (501-508) is used as an input for a predefined illumination rule that assigns the illuminated area (701) in the conjugate plane (700) to the light sources (121, 421-422, 425, 621-631).

16. The method of claim 15, wherein the method further comprises:

the illumination rules are calibrated by iteratively switching the plurality of light sources (121, 421) 425, 621) 631) and capturing in each case the associated illumination profile in the conjugate plane (700).

17. The method of any of claims 13 to 16, further comprising: a reference illumination pattern is selected according to the objective lens (112).

Technical Field

Various examples of the invention relate to variable angle lighting technology. Various examples relate particularly to lighting modules that can be used for variable angle lighting.

Background

Techniques for digital analysis and/or post-processing of images captured with a microscope device are known. In order to obtain a particularly large information content by digital analysis and/or post-processing, variable-angle illumination techniques can be used.

In variable-angle illumination, the sample object is illuminated over a large area or uniformly by different illumination geometries. Then, in each case, a respective image is captured for the various illumination geometries. These images may then be analyzed and/or digitally post-processed. One option is to implement an autofocus application. This is described in US 2017167856 a1 or DE 102017115021a 1. In summary, in this case, the displacement of different object points in the image can be determined depending on the illumination direction achieved by the illumination geometry. Another option is digital post-processing, for example, by merging various images; in this way a resulting image comprising a so-called digital contrast is obtained. The digital contrast may be, for example, a phase gradient contrast or a phase contrast. Corresponding techniques are described, for example, in US 2017/276923 a 1.

Variable angle illumination may be achieved using suitable illumination modules. For example, one exemplary lighting module uses an array of light emitting diodes. An exemplary embodiment is described in US 2019146204 a 1.

By doing so, however, it was determined that large area illumination of a sample object in the object plane by an illumination module consisting of an array of light emitting diodes sometimes has certain limitations. For example, it is observed that the respective illumination may have non-uniformities, i.e. variations in luminous intensity or illumination angle with lateral position in the object plane, for example.

Disclosure of Invention

Accordingly, there is a need for improved techniques to provide variable angle illumination.

In one example, the microscope device includes an objective lens. The objective lens has an entrance pupil. In addition, the microscope device further comprises an illumination module. The lighting module includes a plurality of light sources. The light sources are arranged at a distance from each other. The light source is configured to emit light.

In some examples, the lighting module further comprises a plurality of light guides. The light guide is configured to guide light from the light source to a plane (illumination plane) conjugate to an entrance pupil plane of the objective lens.

A diffusive filter may optionally be arranged in said illumination plane. The latter may expand the light field of the incident light.

The various light sources of the lighting module may be individually switchable. This means that the first light source can be switched on/off and, differently, the second light source can be switched on/off, respectively. To this end, the microscope device may comprise a suitable control unit, i.e. for example a processor executing program code from a memory.

The illumination module may also be referred to as a condenser. The lighting module may implement so-called kohler lighting. The entrance pupil here refers to the image of the aperture stop of the objective, which appears to the observer in the optical principal axis in the plane of the objective (at the axial objective point). The entrance pupil planes are arranged in respective planes of the entrance pupil. The aperture stop is in turn a stop of the objective, which occurs at a minimum angle to an axial object point or image point (axial image point) on the optical axis. Since the diffusive filter is arranged in an illumination plane conjugate to the entrance pupil plane, the diffusive filter is also located in or near the pupil plane. The lateral position of the illumination in the illumination plane is thus converted into an illumination angle in the entry profile plane of the objective or object plane. Therefore, uniform and large-area illumination can be achieved. Furthermore, by switching on/off different light sources, a variable angle illumination may be obtained, wherein different illumination geometries (with respectively different illumination directions) are used.

In general, the lens of the objective lens may also be used as a condenser lens.

The use of a light guide allows a particularly great flexibility in the lateral structure of the illumination in the illumination plane. For example, certain structural limitations of the led array may be remedied. This, in turn, allows flexibility in setting the illumination geometry in the object plane.

By using the diffusion filter, great flexibility is also obtained in the lateral structure of the illumination in the illumination plane. A large area illumination area may be used. This, in turn, allows flexibility in setting the illumination geometry in the object plane.

By the optional combination of the light guide and the diffusive filter, light can be well fed into the diffusive filter. Furthermore, it allows setting customized illumination areas. This, in turn, allows flexibility in the setting of the illumination geometry in the object plane.

As a general rule, there are various options to implement the light guide. In one example, the light guide may be implemented as a cavity between reflective partition walls. For example, no light may be transmitted through the partition wall. The partition wall may have a reflective embodiment. However, the separating wall can also have an at least partially light-transmitting embodiment. The partition wall may extend along a central ray from the light source.

Another exemplary embodiment of the light guide includes an optical fiber. The optical fiber includes a core that guides light therein. For example, the core is made of silicon or any other solid material. The core is surrounded on the outside by a material whose refractive index varies as a function of the core, and therefore total internal reflection occurs at the transition from core to core. A protective layer may be attached around, outside of, the optical fiber. For example, multimode optical fibers may be used that may exhibit total internal reflection of light for different real spatial modes. Typically, the diameter of the optical fiber is about 500 μm. Therefore, many optical fibers can be closely connected to each other. One end of the optical fiber may then be disposed in or near the illumination plane, or adjacent to the diffusive filter. For example, a lens, such as a GRIN lens, may be used to facilitate efficient out-coupling of light.

The diffusion filter has the function of expanding the incident light field. The diffusive filter may cause parallel incident light rays to exit the diffusive filter in different directions. This therefore means that a uniform or more uniformly filled illumination angle space is present. In particular, this may reduce the real spatial variability of the luminous intensity in the illumination plane. This in turn leads to a particularly homogeneous illumination at the object plane or to a reduction of the variation of the luminous intensity for different illumination directions. Furthermore, artifacts (e.g. artifacts that may be due to dust particles located outside the focal plane) may be reduced, for example, in particular by a more uniformly filled said illumination angle space.

Here, there are various options to implement the diffusive filter. The diffusion filter may be implemented with a diffusion plate, for example. The diffuser plate may produce random scattering in the angular space. The diffuser plate may be flat and wide. The diffuser plate may extend perpendicular to the optical axis. The diffuser plate may have a thickness parallel to the optical axis that is much smaller than its width perpendicular to the optical axis. Due to the aperture stop, the edge of the diffuser plate may not be visible when viewed from the axial object point and the axial image point. These edges may be formed by one or more sides or a circumferential side. The diffuser plate may have a front face facing away from the object plane and having a plane normal parallel to the optical axis. The diffuser plate may have a back surface arranged parallel to the front surface and facing the object plane.

Another exemplary embodiment of the diffusive filter comprises a quasi-crystal. The quasicrystal can produce a defined scattering lobe (rather than random scattering).

As a general rule, the light guide may couple light into the front surface. Alternatively or additionally, the light guide may couple light to the circumferential side. The light may then illuminate the back surface in the corresponding illumination area.

The technology described here makes it possible in particular to obtain an illuminated area with a clear demarcation line. In contrast, there is little change in luminous intensity within the illumination area. This makes it possible to achieve a particularly well-defined illumination geometry.

Different combinations of the light guide and the diffuser plate are conceivable in order to obtain different illumination areas. For example, different types of light guides may be used, which differ according to the size of the area illuminated on the diffuser plate. This also enables illumination areas of different sizes to be obtained. For example, a light guide with cavities may be used to illuminate a large illumination area on the diffuser plate, while optical fibers are used to illuminate a small illumination area on the diffuser plate.

A large illumination area in the illumination plane will result in an illumination geometry with illumination from a relatively large solid angle range in the object plane, whereas a small illumination area in the illumination plane will result in a well-defined illumination direction (i.e. illumination from a smaller solid angle range).

Using different configurations for the illumination geometry is also advantageous in facilitating application of the angularly variable illumination to different application scenarios. For example, an illumination geometry with only one illumination direction in each case may be helpful for autofocus applications; on the other hand, illumination geometries illuminated from a large solid angle range may help to generate phase contrast images.

As a general rule, the light sources may emit light of different wavelengths or with different light emission spectra. This means that the light source may emit light of different color temperatures. Sometimes, a plurality of light sources with different luminescence spectra may be assigned to the light guide. This can be achieved-for example, depending on the mode of operation of the microscope-using a suitable wavelength or a suitable wavelength range; this may, for example, reduce the exposure of light sensitive sample objects. However, flexible digital analysis/post-processing is possible. White light may also be produced.

Another option involves the use of a fluorescent material in combination with the diffusive filter. This may enable adaptation of the spectrum. This may, for example, produce a spectral distribution representing white light.

In order to achieve a particularly flexible variation of the illumination area of the diffusive filter (and, thus, a particularly flexible adaptation to the illumination geometry or illumination solid angle used in the object plane), the light guide may be arranged in a movable manner with respect to the diffusive filter. To this end, the microscope arrangement may comprise an actuator configured to position the at least one light guide in an opposing manner with respect to the diffusive filter. To this end, the actuator can move at least one light guide and/or the diffusion filter relative to a reference coordinate system of the microscope arrangement. For example, an electric motor may be used, e.g. with linear drive or magnetic drive. As an alternative or in addition to the positioning of the light guide, it is also possible to use a deformation, in particular an elastic deformation, of the light guide. This may for example set the field width of the light at the exit of the light guide. As a result, the illumination area can in turn be changed, in particular in terms of size or shape.

For a better lateral structuring of the light distribution in the illumination plane, i.e. for a better definition of the illumination area, the diffuser plate may also have reflective structures which extend in lateral direction, i.e. in the entrance face or exit face. Thus, the various sections of the diffuser plate may be structurally defined; as a result of this structural definition, the lateral extent of the illumination area can be defined, for example, by reflection on the reflecting structure.

In principle-as mentioned above-it is not necessary to use the diffusive filter. A homogenized illumination in the illumination plane may also be achieved by, for example, the light guide promoting lateral coupling of light. In other words, this means that light can cross between adjacent light guides. This avoids hard transitions in the illumination plane. Thus, the light guides may be arranged adjacent to each other in real space. For example, the light guides may extend parallel to each other. For example, the outer edges of adjacent light guides may be touching. In such a configuration, in particular, the light guide may be implemented as a waveguide.

Various modes of operation of the microscope device may be assisted by the techniques described herein. Depending on the mode of operation, different imaging objectives can be achieved. That is, for example, different information contents may be extracted. For example, an autofocus mode of operation may be used. Here, it may be desirable to direct light onto the object plane from a well-defined illumination direction, i.e. from a small solid angle range. This enables a sharp displacement of the imaged object to be observed from images captured under illumination in different illumination directions, and the distance to the focal plane can be accurately determined from the displacement, which should be accurately measured. On the other hand, another mode of operation, which may be referred to as a digital contrast mode of operation, may be desirable, i.e. to use an illumination geometry in which light reaches the object plane from a relatively large solid angle range in each case. By means of the respective images, this may result in phase-contrast-like result images, which are captured under illumination with the respective illumination geometry and combined to form the result image, for example. Finally, the bright field mode of operation would be another option. In this case, the light can reach the object plane from all directions, in particular from all directions through the aperture stop.

This operation-dependent driving of the light source mode may be achieved, for example, as follows: a reference illumination pattern may be stored. These may define an illumination area in the illumination plane. More precisely: the reference illumination pattern may determine the brightness, i.e. the structure of the light field in the illumination plane, from a lateral position in the illumination plane perpendicular to the optical axis. Depending on the mode of operation, different reference illumination patterns may be selected.

The various light sources can then be switched on and off in such a way that the actual illumination pattern in the illumination plane coincides as much as possible with the reference illumination pattern.

For example, lighting rules may be used for this purpose. The lighting rules may specify that a certain lighting area in the lighting plane is illuminated (or some other area remains dark) when a certain light source is turned on. This can be determined for all light sources. In this way, the reference illumination pattern can be reproduced by appropriate superposition of the individual illumination areas of the light sources to be switched on.

The illumination rules may also define the luminous intensity of the illumination area. This would allow, for example, to operate the light sources with different currents in order to obtain an adjusted luminous intensity according to the reference illumination pattern.

The illumination rules may define light intensity variations within the illumination area in addition to the real spatial extent of the illumination area. This allows, for example, compensating for complementary intensity variations of the two light sources by appropriate superposition. The luminous intensity may also be set by the lighting rules. For this purpose, for example, a fast on/off switch with an adjustable duty cycle can be used, or a current can be set.

The lighting rules may be specified. However, the lighting rules may also be determined by calibration. For this purpose, the individual light sources can be switched on separately (repeated switching), and the illumination area in the illumination plane can be determined by a camera focused on the illumination plane. Thus, (i) the extent of the illumination area, (ii) the luminous intensity of the illumination area and/or (iii) the luminous intensity variation within the illumination area may be determined and may be stored accordingly in the illumination rules.

Depending on the objective lens of the microscope device with interchangeable objective lens capability, different degrees of reference illumination patterns perpendicular to the optical axis may sometimes be required. This is because the entrance pupil of the objective lens may have different ranges. For this reason, it may be desirable to select the reference illumination pattern depending on the objective lens employed.

The control unit of the microscope device is configured to load the program code from the memory and to execute the program code. This results in a method being performed. The method includes selecting an operating mode of the microscope device from a plurality of operating modes. The method further comprises driving a plurality of light sources of an illumination module of the microscope arrangement in order to selectively emit light or not in each case. Here, the plurality of light sources are disposed to be spaced apart from each other by a certain distance. Furthermore, the light is directed into a plane conjugate to the entrance pupil plane of the objective, i.e. into the illumination plane. The diffusion filter may be located here. The operating mode of the plurality of operating modes may comprise one or more of: autofocus, digital contrast, and bright field microscopy.

The computer program or computer program product or computer readable storage medium comprises program code. Which may be loaded and executed by a processor. This results in a method being performed. The method includes selecting an operating mode of the microscope device from a plurality of operating modes. The method further comprises driving a plurality of light sources of an illumination module of the microscope arrangement in order to selectively emit light or not in each case. Here, the plurality of light sources are disposed to be spaced apart from each other by a certain distance. Furthermore, the light is directed into a plane conjugate to the entrance pupil plane of the objective, i.e. into the illumination plane. The diffusion filter may be located here. The operating mode of the plurality of operating modes may comprise one or more of: autofocus, digital contrast, and bright field microscopy.

The features specified above and those yet to be explained below can be used not only in the respectively specified combination but also in other combinations or alone without departing from the scope of the invention.

Drawings

Fig. 1 schematically shows a microscope arrangement according to various examples;

fig. 2 schematically illustrates an array of light emitting diodes of an illumination module of a microscope arrangement according to various examples;

fig. 3 schematically illustrates luminous intensity variations or luminance fluctuations of a light emitting diode array in a plane conjugate to an entrance pupil plane (illumination plane) according to various examples;

FIG. 4 is a flow diagram of a method according to various examples;

fig. 5 schematically illustrates different illumination patterns with illumination areas and dark areas in an illumination plane, according to various examples;

FIG. 6 schematically illustrates a light guide and a diffusive filter in an illumination plane, according to various examples;

FIG. 7 schematically illustrates a light guide and a diffusive filter in an illumination plane, according to various examples;

FIG. 8 schematically illustrates the use of multiple light sources per light guide, according to various examples;

FIG. 9 schematically illustrates a light guide and a diffusive filter as an optical fiber in an illumination plane, according to various examples;

FIG. 10 schematically illustrates a diffusive filter in an illumination plane, in accordance with various examples;

FIG. 11 schematically illustrates a diffusive filter in an illumination plane, according to various examples.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the following description of the embodiments should not be construed in a narrow sense. The scope of the present invention is not intended to be limited by the embodiments or the drawings described below, since they are for illustrative purposes only.

The drawings are to be regarded as illustrative in nature, and elements illustrated in the drawings are not necessarily shown true to scale. The various elements are shown in a manner that will make apparent to those skilled in the art both their function and their general purpose. Any connection or coupling between functional blocks, devices, components or other physical or functional units illustrated in the figures or described herein may also be achieved through an indirect connection or coupling. The coupling between the components may also be established by means of a wireless connection. Functional blocks may be implemented in hardware, firmware, software, or a combination thereof.

Techniques for providing variable angle illumination are described below. This means that different illumination geometries can be used for large-area illumination of the object plane, which differ from one another in the angle of the incident light.

The angularly variable illumination may be uniform and formed over a larger area in the object plane. This means that in the bright field region of the object plane there is no or should be no significant change in the luminous intensity. The solid angle or solid angles at which the rays are incident in the object plane, as a function of their lateral position in the object plane, are substantially unchanged (for the direction of illumination by the aperture stop and the field stop).

Based on various aspects of the discovery, for example, variable-angle illumination may be achieved by spatial division of an illumination planePlane of the sheet materialThe mode (conjugate) is located on the imaging pupil of the objective lens. The variable-angle illumination is achieved by virtue of only a partial illumination plane, and thus only a partial imaging pupil (imaging pupil), being illuminated. For different illumination geometries, a uniform and complete illumination of the imaging field in the object plane should be achieved. For this reason, there are some technical approaches, although with the disadvantages:

(i) mechanical stop in the illumination plane: mechanical switching and therefore very slow and high optical losses. See, for example, DE 102017115021a 1. (ii) Liquid crystal display in illumination plane: the light loss is high due to confinement to polarized light, with switching times as long as a few milliseconds until the illumination modulation is set within a segment. (iii) Digital Micromirror Device (DMD) in the illumination plane: limited etendue, expensive, and limited contrast because light is also scattered at the edges of the micromirrors in the dark. (iv) Segmented led array: the mesh width between each LED is larger; due to the tight packaging, there is a heat dissipation problem.

The techniques described herein facilitate solutions that combine several advantageous aspects together. They are: fast electronic switching of a single illumination area or multiple illumination areas in an illumination plane; mechanical movement of parts is not required to achieve different illumination areas; full illumination of the illumination plane is facilitated, i.e. all angular ranges in the pupil can be used for illumination, i.e. a "dark net" is avoided; flexibility in the number and implementation (area) of the illumination areas, so that illumination geometries with a large solid angle range of illumination can also be provided on the object plane; in a particular embodiment, the illumination pattern for the various imaging optical units of the objective can be selected in the illumination plane, for example geometrically optimized for the size of the illuminated region; simple interchangeability of individual LED lighting units, with little requirement for the inherent beam shaping capabilities of the LEDs (with or without domes); on the same control interface, the previous illumination in the previous reference microscope device is simply replaced. Another optional advantage is the simple controllability of the spectrum if multiple light sources are used per channel. In particular, the spectrum can be set without compromising the uniformity of the illumination.

In some technologies, light guides are used for this purpose. For this purpose, the light emitted by the individual electronically switchable light sources can enter the conjugate plane of the objective pupil (the so-called illumination plane) via a light guide. The light guide can be embodied here in such a way that the light emitted by each light source (e.g. light-emitting diode, LED) is brought to spatially separated surface elements (illumination areas) of the illumination plane. This allows different illumination areas in the illumination plane to be switched on or off by means of an electrical switch of the light source.

Optionally, an angular homogenization is obtained in the illumination plane of the light by means of light diffusion, so that a uniform and complete illumination of the sample region is possible, irrespective of which illumination region in the illumination plane is switched on or off by means of the associated light source. This may be achieved, for example, by a segmented diffuser or any other diffusive filter.

Fig. 1 schematically shows a microscope arrangement 90 according to various examples. The microscope device 90 includes a control unit 115, for example, implemented by a CPU or FPGA or ASIC. The control unit 115 is configured to control various other units or modules of the microscope apparatus.

Accordingly, the microscope device 90 further comprises an illumination module 111, an objective lens 112, a sample holder 113 and a detector 114. For example, the control unit 115 may drive the lighting module 111 differently according to an operation mode. For example, the control unit 115 may drive the illumination module 111 such that the latter realizes different illumination geometries of the angularly variable illumination in the object plane. The control unit 115 may drive the detector 114 to capture images of various illumination geometries, respectively. The detector 114 may have a plurality of detector elements as pixels. For example, a CMOS detector may be used. The control unit 115 may then analyze and/or post-process the images, i.e. e.g. determine blurring of the sample object or combine multiple images to form a resulting image with digital contrast.

Fig. 2 shows a detail of an exemplary embodiment of the LED array of the lighting module 111. The LED array includes a plurality of LEDs 121. As is apparent from fig. 3, the active regions of the plurality of LEDs 121 are at a distance from each other. This results in non-uniform luminous intensity in the illumination plane. As shown in fig. 3.

In fig. 3, the luminous intensity in the illumination plane 700 is plotted along the line X-X' of fig. 2 as a function of the lateral position in the illumination plane 700 (xy-plane, perpendicular to the beam propagation in the z-direction). Clearly, there is a variation in luminous intensity in the illumination plane 700 due to the network between the LEDs (see in particular the vertical arrows in fig. 3). Therefore, there may be non-uniformities in the illumination geometry; the luminous intensity may vary unnecessarily depending on the angle in the object plane as a function of the angle in the object plane. A technique for obtaining a small variation in the luminous intensity is described below.

Fig. 4 schematically illustrates a method according to various examples. The method of fig. 4 may be performed by a processor, for example, by loading program code from memory, and then executing. The method may be performed by a processor of a control unit of a microscope device, such as the processor of the control unit 115 of the microscope device 90 in fig. 1. Reference is made to such embodiments as examples.

The optional steps are illustrated in fig. 4 with dashed lines.

In optional step 9000, an operating mode for operating the microscope device 90 is initially selected. Exemplary modes of operation include, for example: digital auto focus, digital contrast, and bright field. For example, variable angle illumination is used for each of digital autofocus and digital contrast. However, this is not the case for the bright field. Dark field illumination may also be selected as another mode of operation.

Then, depending on the selected mode of operation, the light sources 121 are driven to achieve one or more lighting geometries, as in step 9001; this means that, for example, different LEDs 121 are switched on and off depending on the mode of operation. In particular, depending on the illumination geometry, lateral structures of different luminous intensities in the illumination plane 700 may be used. In this case, the various illumination geometries correspond to various illumination patterns in the illumination plane 700. The various illumination geometries may be turned on in sequence or multiplexed, e.g. in frequency space.

Then, in step 9002, one or more images are captured, to be precise at least one image from each illumination geometry of step 9001. To this end, the detector 114 is suitably driven and read.

There is analysis and/or post-processing in optional step 9003. For example, the distances of objects in the respective images of step 9002 may be determined for an autofocus application. The multiple images of step 9002 may also be combined to obtain a resulting image with digital contrast. In general, in the case of bright field imaging, no analysis or post-processing is required.

Next, exemplary details for the implementation of block 9000 are described herein. In principle, there are a variety of possible variations to implement step 9000. For example, different reference illumination patterns may be loaded depending on the mode of operation. The reference illumination pattern is determined in the illumination plane 700. The reference illumination pattern 700 may specify an illumination area to be used in the illumination plane 700.

As an example, different reference illumination patterns 501 and 508 are imaged in fig. 5 (here, white in each case denotes an illuminated area 701 in the illumination plane 700 and black denotes an unlit area 702). Here, in the case of bright field illumination, the reference illumination pattern 501 may be selected. The reference illumination pattern 501 defines a full area of illumination area that extends into the entire illumination plane 700 with a lateral dimension 709. The illumination pattern corresponding to the reference illumination pattern 501 is implemented such that the object plane is uniformly illuminated from all possible angular ranges.

However, this is not the case for reference illumination pattern 502-504: there, the object plane is illuminated from only certain solid angles (half of the solid angle quadrant of the reference illumination pattern 502-503 and the solid angle of the reference illumination pattern 504).

For the reference illumination pattern 502-504, in particular, clear separation lines between the respective illuminated areas (illumination areas) 701 and the non-illuminated areas 702 are clearly visible.

In the case of a punctiform illumination area 701 realized according to the reference illumination patterns 505 and 506, the object plane is illuminated from a well-defined illumination direction. The reference illumination pattern 507 facilitates illumination from four independent illumination directions simultaneously.

There may also be a combination of large area illumination areas 701 and spot illumination areas 701 as shown with reference to illumination pattern 508.

Then, the light source 121 may be driven differently depending on the reference illumination pattern 501-508. This means that different light sources are switched on and off according to the reference illumination pattern 501-508. Thus, the actual illumination pattern in the illumination plane 700 may at least approximate the selected reference illumination pattern.

To achieve this, the respectively selected reference illumination patterns 501-508 may be used as input for the predetermined illumination rules. The illumination rules may assign illumination regions 701 to various light sources 121 according to reference illumination patterns 501-508. For example, the point-like illumination areas 701 of the reference illumination blur 505 and 508 may each be assigned to a separate LED 121. A planar illumination area 701 according to the reference illumination pattern 501 and 504, 508 would be possible by turning on one or more light sources.

In general, the size of the illumination area 701 obtained by the light source may depend on the type of light source (e.g. large area OLED versus collimated laser diode) and/or may be arranged by using a suitable light guide-having an appropriately shaped exit face. Alternatively or additionally, the size of the illumination area 701 may also be set by the properties of a diffuser (described below), e.g. by the reflective structure of the diffuser.

The lighting rules may be determined in a separate calibration according to step 9009 (see fig. 4). To this end, the effect of the various available LEDs 121 on the illumination of the illumination plane 700 can be measured. For this reason, the respective LEDs 121 may be repeatedly switched.

Thus, there may be a particularly accurate analysis and/or a particularly good post-processing, and according to various examples described herein, the quality of the illumination geometry may be improved. For this purpose, in particular, it is possible to avoid pronounced brightness fluctuations in the illumination region or excessive or insufficient representation of certain illumination directions in the illumination geometry in the object plane. To achieve this, an arrangement may be made as shown in fig. 6.

Fig. 6 is a side view of the illumination module 111 (object plane shifted to the left along the z-axis, but not shown here). Here, two light sources 421, 422 are used. The light rays are guided by the light guide 400, here the cavity between the reflective separating walls 401 and 403, i.e. the waveguide, to a diffuser 409, which diffuser 400 is arranged in the illumination plane 700 and extends over the entire lateral dimension 709 of the illumination plane 700.

Due to the use of the light guide 400 as a waveguide, a particularly large illumination area 701, for example half the area in the case of fig. 6, can be obtained in the illumination plane 700.

In particular, light is coupled into a front side 409A (facing away from the object plane) of the diffuser 409 and light exits the diffuser 409 at an opposite back side 409B (facing the object plane). The diffuser 409 reduces the variation of the luminous intensity in the lateral direction within each illumination area 701.

Alternatively, the partition walls 401 and 403 may be configured such that they do not absorb any light but reflect light. Thus, the surface may have a certain roughness to suitably homogenize the angular spectrum of the incident light in the illumination plane 700.

The diffuser 409-or generally any other suitable diffusing filter-may in particular fulfill the function of avoiding dark meshwork areas between the LEDs 421 and 422. Another function of the diffuser 409 (or generally a diffusing filter) may be to increase the emission angular range of the light source (generally, this need not be the case with LEDs as light sources, but in some cases may be the case with other light sources). For this reason, the diffuser 409 may be selected and installed in such a way that such shadow-net effects are avoided due to the diffusion of light within the diffuser. Thus, if desired, the illumination plane 700 may be fully illuminated — i.e., for example, in the case of an operating mode corresponding to bright field imaging; see reference illumination pattern 501 in fig. 5-and the corresponding pupil plane of objective 112 can be fully illuminated.

The example described in fig. 6 may be extended in other variations. A corresponding example is shown in fig. 7. Here, there is a combination of LEDs 421 and 422 coupled to the diffuser over a large area and one or more additional LEDs 425 locally attached in the diffuser 409 (see fig. 6). Here, the light guide is realized by an optical fiber 481.

Although a combination of a waveguide and an optical fiber is shown in the example of fig. 7, it is also conceivable to use only an optical fiber as the light guide in other examples.

The illumination area 701 resulting from the waveguide-coupled large area LEDs 421 and 422 is larger than the illumination area 701 resulting from the locally input coupled LEDs 426 (e.g., reference illumination patterns 502 and 504 and 505 and 507).

Here, this implementation is only one example. For example, a larger illumination area 701 may also be obtained by a suitable optical fiber, for example, using a GRIN lens or a resilient exit surface.

Another option relates to embodiments with adjustable "light colors". An example is shown in fig. 8. Here, in each case a plurality of LEDs 421 and 423, and 422 and 424, are arranged per waveguide (again defined by the partition walls 401 and 403). These have different emission spectra. Examples include: RGB-LEDs, warm and cold white LEDs, white light and IR, etc. Multiple light sources with different emission spectra can also be used without a light guide. Thus, FIG. 8 shows in general terms an exemplary embodiment of a scheme using multiple light sources in each channel. In this manner, it may be used in the various examples described herein.

Fig. 9 illustrates the use of optical fibers 481 and 486 as light guides. The optical fibers typically define a relatively small illumination area 701 (see also fig. 7).

Here, a plurality of optical fibers 481-. In this way, a relatively large illumination area 701 may be generated by each light source.

The light source (not shown in fig. 9) may also be flexibly attached to another location (not necessarily directly to the condenser of the microscope device 90).

Here, the fibers 481-486 need not be arranged in a sorted manner-rather, in the calibration of step 9009 (see fig. 4), the assignment of LEDs can be determined by recording images of the fiber ends and can be stored as illumination rules in the switch plan.

Another option for achieving an advantageous light guide is to arrange the LEDs in front of not in nature, but in front of a large phosphor layer (or generally any other fluorescent material) which is shared by all people. This is shown in fig. 10. As a result, the phosphor layer is selectively drivable, secondary, passive light sources (without boundaries between the switching light sources 421 and 422).

Although the variant of coupling light into the front face 409A has been described above, in other variants it is also possible to couple light input into the circumferential face 409C, i.e. the side face of the diffuser plate 409, as an alternative or additional possibility; a corresponding example is shown in fig. 11.

Fig. 11 is a side view (top) and a plan view (bottom) of the diffuser plate 409 in the illumination plane 700.

Here, LEDs 621 and 631 are concentrically arranged around the diffuser plate and illuminate the circumferential surface 409C.

Although fig. 11 shows that no light guide variation is used between the LEDs 621-631 and the circumferential surface 409C, light guides may be used in other examples-e.g. waveguides and/or optical fibers as described above.

Fig. 11 also shows that the diffuser plate 409 has structures 601 (e.g., reflective partition walls) arranged in a lateral direction perpendicular to the optical axis such that square illumination areas 701 can be created in a clear partition line fashion (see, e.g., reference illumination patterns 502 and 503 in fig. 5). The illumination area may be flexibly defined by the structure 601.

The use of such a structure 601 is not limited to the illustrated example, but may be used in other examples described herein.

For example, the structure 601 may form trenches or metallic inclusions (doping), regions with increased roughness, locally annealed regions, and the like.

In summary, the above describes a technique that allows flexible illumination and non-illumination areas to be defined in the illumination plane (i.e. in a plane conjugate to the entrance pupil of the objective lens of the microscope device).

Various variations of the above-described examples are contemplated.

For example, the use of a light guide is not mandatory (see also fig. 10 and 11, for example).

Furthermore, it is sometimes possible to dispense with the arrangement of diffusers or generally diffusion filters in the illumination plane. By using, for example, a (partially) light-transmitting partition wall of the waveguide between the light source and the illumination plane (see fig. 6; partition wall 401) the luminous intensity and the light direction in the illumination plane 700 can be homogenized. This corresponds to lateral coupling between the light guides. The partition walls may be made of a light scattering material, for example, having roughness.

Another variant for flexibly positioning the illumination areas 701 in the illumination plane 700 is based on the use of actuators for moving or deforming the light guide plate. For example, a flexible or elastic waveguide structure may be used. The latter may then be rotatable and/or resizable. For example, a "rubber" light guide may be used, which is arranged in a twisted manner between the LEDs and the illumination plane. For example, the actuator may adjust the cross-section of the light outlet at the illumination plane, e.g. from polygonal to circular, etc.

The various techniques described herein are based on the finding that the etendue of the microscope arrangement is decisively determined by the optical and mechanical dimensions of the light source used. Here, the LED is a substantially planar emitter. Light is emitted into the half-space. In a reference embodiment, this light is captured by the collector optical unit and transmitted as a virtually infinite beam into the optical transmission means of the microscope until reaching the object.

When reflected light occurs on the microscope, the etendue corresponds to the objective pupil: (in this case, the objective lens is both the condenser and the detection objective). Here, the circular diameter of one LED is about 1.5 mm to 3 mm. In the case of transmitted light, the field number of the microscope is 23 mm (large object field) while having the largest possible range of numerical aperture values (in order to obtain the best performance of the algorithm for calculating the digital contrast in as many objectives as possible; in practice: a numerical aperture of typically between 0.3 and 0.8, in the case of conventional tubes, typically 0.55) the corresponding LED surface has an inscribed circle diameter of between about 3 mm and 6 mm in order to satisfy the etendue.