Illumination system, microplate reader and method for generating at least one image of biological or chemical samples using a microplate reader

Abstract

The invention relates to an illumination system (10), in particular for a microplate (3) in a microplate reader (1), with a light source (12) for emitting optical radiation, which is configured within the illumination system (10) as a beam path (21) with an optical axis (22) and has a radiation cross-section that varies, in particular along the beam path (21), with a field aperture (14) which is arranged directly or indirectly adjacent to the light source (12) and has an aperture opening (14a) for the beam path (21), with an aperture diaphragm (16) which is arranged along the optical axis (22) at a distance (23) from the field aperture (14) and has a further aperture opening (16a) for the beam path (21), and with at least one lens which is arranged along the optical axis (22) in the beam path (21).The invention is characterized in that a central aperture (19) can be arranged in the beam path (21) within the distance (23) between the luminous field aperture (14) and the aperture aperture (16), wherein the central aperture (19) has an aperture area (20) with reduced transmission, in particular to the point of complete transmission suppression, in a region of the optical axis (22). The invention further relates to a microplate reader (1) and a method for generating an image of biological or chemical samples with a microplate reader (1).

Description

[0001] The invention relates to an illumination system, in particular for a microplate in a microplate reader, according to the preamble of claim 1, a microplate reader according to the preamble of claim 16, and a method for generating at least one image of biological or chemical samples with a microplate reader according to the preamble of claim 22.

[0002] Microplate readers for the analysis of chemical and / or biological samples are well-known in the art. A microplate is a sample carrier for performing photometric or other measurements, featuring a multitude of regularly spaced wells in which the individual samples are placed. A microplate reader serves to "read" microplates by performing photometric measurements at the individual wells. For this purpose, the microplate reader incorporates measurement and analysis modules, such as a photodetector, which determines the luminescence, fluorescence, and / or absorption of the samples in the wells. Microplate readers may also include cameras that enable the acquisition of images of the microplate and, in particular, of the samples in the individual wells.For this purpose, the microplate is inserted into a receiving device which is movable relative to the camera or a measurement and analysis module and can be positioned, for example, via a positioning mechanism that allows movement in the X and Y directions. To sequentially read out the individual wells, these are moved one after the other by the positioning mechanism into the working area of ​​the optical element and the camera.

[0003] Photometric analysis of samples in a microplate using a microplate reader is employed in a wide range of applications, including the detection of biological, chemical, biochemical, or physical reactions of the samples. This involves capturing images of the samples or their contents in the individual wells of the microplate through the base of the microplate, primarily using a camera.

[0004] For microscopic examination of samples in microplates, and especially for image acquisition, illumination of the microplate or the individual wells is required. There are two important types of sample illumination: dark-field illumination and bright-field illumination. All illumination methods share the common requirement that light must be directed to the sample in the individual wells so that the sample can be analyzed by observing the contrasts created through reflection, absorption, and / or transmission, or by phase shift. Several bright-field illumination techniques have become established, particularly oblique illumination, critical illumination, and Köhler illumination, which is considered the gold standard in microscopy.

[0005] A disadvantage of these illumination methods is that the surface tension of the sample liquid, as well as the boundaries of the individual wells in the microplate, can cause a so-called meniscus to form, leading to significant image degradation. This meniscus creates a lens effect, resulting in a truncated cone-shaped intensity distribution of the illumination at the bottom of each well. This intensity distribution leads to overexposure of the image, particularly in its center, which makes further processing and, in particular, analysis of the image difficult or even impossible.

[0006] To avoid such a meniscus effect, it is known from the prior art, for example US623911B1, to place additional elements on or attach them to the microplate to counteract the lensing effect caused by the sample fluid and the geometry of the microplate. However, this has the disadvantage that the entire microplate must be fitted with a corresponding additional element, resulting in each well of the microplate receiving a corresponding and identical correction for all wells. Another disadvantage is the associated effort, as it is not possible to react immediately during an image acquisition or series of acquisitions if such a meniscus effect is detected. Instead, the microplate must be removed from the microplate reader, a corresponding additional element placed on the plate, and then the plate reinserted into the microplate reader.Especially with chemical or biological samples, where measurement is time-critical or which need to be measured in a specific atmosphere, this can lead to the sample no longer being measured or being measured with a distorted result.

[0007] Furthermore, it is known from the prior art to compensate for or balance the meniscus effect in microscopes using optical deflection elements made of viscous liquid, as described, for example, in DE 10 2015 111 426 B3. The disadvantages here, too, are the very high effort required to adjust the compensation and the reproducibility issues caused by the use of viscous liquids as deflection elements.

[0008] It is therefore an object of the present invention to provide an illumination system, a microplate reader, and a method for generating at least one image of chemical or biological samples with a microplate reader, which enable a simple and flexible correction of the meniscus effect.

[0009] The aforementioned problem is solved by an illumination system, in particular for a microplate in a microplate reader, according to claim 1, and by a microplate reader according to claim 16. Furthermore, the problem is also solved by a method for generating at least one image of biological or chemical samples with a microplate reader according to claim 22.

[0010] Advantageous embodiments of the lighting system are set out in claims 2 to 15. Furthermore, preferred embodiments of the microplate reader are set out in claims 17 to 21. Preferred embodiments of the method are set out in claims 23 to 25.

[0011] The microplate reader can be configured, in particular, to carry out a method for generating at least one image of biological or chemical samples, or a specific embodiment thereof. The method for generating at least one image of biological or chemical samples can be carried out, in particular, with a microplate reader or a preferred embodiment thereof.

[0012] The illumination system according to the invention, particularly for a microplate in a microplate reader, comprises a light source for emitting optical radiation, which has a beam path extending along an optical axis within the illumination system and has a radiation cross-section that varies, in particular along the beam path. The illumination system further comprises a field aperture, which is arranged directly or indirectly adjacent to the light source and has an opening for the radiation path. In addition to the field aperture, the illumination system comprises at least one lens, which is arranged along the optical axis in the beam path, and an aperture diaphragm, which is arranged along the optical axis at a distance from the field aperture and has a further aperture opening for the radiation path.

[0013] The illumination system according to the invention is characterized in that a central aperture can be arranged in the beam path within the distance between the illuminating field aperture and the aperture aperture, wherein the central aperture has an aperture area with reduced transmission in a region of the optical axis, in particular up to the point of preventing transmission.

[0014] The central diaphragm, which is or can be arranged between the luminous field diaphragm and the aperture diaphragm in the beam path, comprises a diaphragm area in the region of the optical axis, which prevents at least part of the radiation transmission in the area around the optical axis where the diaphragm area is formed. In particular, the diaphragm area is designed such that it has a transmission coefficient of less than 100% for the radiation and is at least partially opaque.

[0015] The central diaphragm, which can be positioned in the beam path and has a transmission-reducing aperture, at least partially blocks the passage of central radiation located near the optical axis. This reduces the intensity of the radiation and also blocks radiation at certain angles that would otherwise lead to overexposure or high intensity due to the meniscus effect. The central diaphragm alters the radiance profile, thus compensating for the intensity profile caused by the meniscus effect. The diaphragm's position within the beam path of the lighting system also allows for quick and easy repositioning or removal as needed.The illumination system is flexible and can be adapted to the samples arranged in the wells of the microplate. The central diaphragm, with its aperture area, generates illumination that compensates for the meniscus effect, enabling more accurate and reliable measurements across the entire depth of a well. The illumination system is specifically designed and used to compensate for the meniscus effect.

[0016] Preferably, the illumination system is a brightfield condenser.

[0017] A preferred embodiment of the illumination system is characterized by the fact that the center of gravity of the aperture area coincides with the optical axis. In particular, the aperture area is located essentially in the center of the radiation cross-section. This essentially minimizes or removes the central radiation, thus reducing its intensity or even eliminating it entirely.

[0018] Advantageously, the central aperture is arranged outside the plane of the aperture diaphragm and / or the illumination field diaphragm. The central aperture is specifically not located in either of the two diaphragm planes, and its position between the aperture diaphragm and the illumination field diaphragm can be freely selected or adjusted according to requirements and depending on the radiation and, in particular, its intensity.

[0019] Preferably, the transmission coefficient of the aperture area of ​​the central aperture is constant across the entire aperture area. Alternatively, the transmission coefficient of the aperture area has a profile, preferably a graduated profile. In particular, the profile is designed such that it exhibits a transmission coefficient that increases towards the outside. By designing the aperture area, the intensity or attenuation of the radiation within the aperture area can be specifically adjusted or selected and adapted to the requirements of the lighting system. In particular, a graduated profile with a center of gravity in the region of the optical axis has the advantage that the central radiation is reduced or even completely blocked, whereas the radiation present outside the central radiation is reduced less, since this helps to compensate for the meniscus effect.This improves the overall illumination of the recess or recesses.

[0020] Another advantageous embodiment of the lighting system is characterized by the fact that the aperture area at least partially absorbs, scatters, and / or reflects the radiation. The specific way in which the reduced transmission of the radiation occurs depends on the design of the aperture area, whereby the radiation can be absorbed, scattered, and / or reflected.

[0021] Alternatively, or preferably additionally, the aperture area is structured. Such structuring can also achieve reduced transmission downstream of the central aperture, particularly in the area of ​​the central radiation.

[0022] Preferably, the aperture area is smaller than or equal to the radiation cross-section in the region of the central aperture. The aim is to ensure that sufficient radiation can still pass through the central aperture to enable measurement with the illumination system.

[0023] Alternatively, or preferably additionally, the aperture area has a round, oval, or rectangular cross-section. In particular, the choice of cross-section may depend on the radiation cross-section and / or the beam path.

[0024] A further preferred embodiment of the illumination system is characterized in that the aperture area has a diameter or length of at least one principal axis or side edge in the range of 1 mm to 12 mm. Preferably, the diameter or length is in the range of 1.5 mm to 6 mm. Particularly preferably, the diameter or length of the aperture area is 4 mm. In particular, the diameter or length of at least one principal axis or side edge of the aperture area can also depend on a magnification of the illumination system, which is determined by and dependent on the lenses of the illumination system.

[0025] Advantageously, an aperture area is formed within the aperture area, particularly in the region of the optical axis. Preferably, the ratio of aperture area to diameter of the aperture area or length of a principal axis or side edge of the aperture area is a maximum of 50%. The aperture area is significantly smaller and comprises only a portion of the aperture area, allowing radiation to pass through the central aperture in the region of the aperture area. This can, among other things, lead to sufficient illumination of the individual samples in the wells of the microplates, with the aperture area outside the aperture area of ​​the central aperture providing sufficient compensation for the meniscus effect. Preferably, the aperture area is transparent to radiation.Alternatively or preferably additionally, the aperture area can also be designed in such a way that its transmission coefficient is larger than that of the transmission coefficient of the aperture area adjacent to the aperture area.

[0026] Preferably, the central aperture is essentially transparent to radiation outside the aperture area. Alternatively, or preferably additionally, the central aperture consists solely of the aperture area and is formed without any further elements surrounding it.

[0027] Alternatively, or preferably additionally, the central aperture has a support that is transparent to the radiation. The central aperture can be positioned within the beam path using a suitable support, without this support having a significant influence on the radiation or the beam path and the illumination of a sample in a recess of the microplate.

[0028] A slide is the preferred central aperture. Slides offer the highest contrast with finely adjustable, gradual density. Unlike controllable transmission filters, this is particularly easy and inexpensive to manufacture and can be replaced quickly and easily if needed.

[0029] Alternatively, or preferably additionally, the central aperture is designed as a controllable transmission filter, in particular as a liquid crystal display, for example an LCD. The LCD can preferably be an LCD memory display. Suitable control of the liquid crystal display allows iterative or algorithmic optimization of the image in the display and thus of the aperture range to compensate for the meniscus effect. In this way, the aperture range can be quickly and easily adapted to the respective conditions.

[0030] Alternatively, or preferably additionally, the central aperture is made of glass or plastic, wherein the aperture area is an integral part of the central aperture and / or the aperture area is formed by an additional element on the central aperture. If the aperture area is formed integrally, the central aperture can be a single element or it can be formed by combining several elements. Forming the aperture area on the central aperture with an additional element has the advantage that this additional element can be flexibly adapted, and the aperture area can be quickly and easily adjusted to the respective requirements. In particular, the additional element is fixed to the central aperture, preferably by being glued to it.

[0031] In another preferred embodiment, the position of the central aperture can be changed within the distance between the illumination field aperture and the aperture aperture. The position of the central aperture can thus be flexibly adjusted within the distance between the aperture aperture and the illumination field aperture.

[0032] Alternatively, or preferably additionally, the central diaphragm can be removed from the beam path. The central diaphragm can be removed from the beam path, for example, when analyzing samples that do not require compensation for a meniscus effect or that do not exhibit such an effect at all. The illumination system can be flexibly adapted to the specific requirements, and the central diaphragm can be quickly and easily positioned in or removed from the beam path as needed.

[0033] Preferably, the central aperture is movable via a positioning device, in particular a positioning mechanism. The positioning device preferably has an electric drive and / or a fluid-driven drive, in particular a hydraulic or pneumatic drive, and / or another type of mechanical drive. By means of the positioning mechanism, the central aperture can be positioned between the light field aperture and the aperture aperture, and can also be placed in or removed from the beam path.

[0034] In a preferred embodiment, the positioning device comprises a linear drive and a slide movable relative to and along the linear drive, with the central aperture being arranged directly or indirectly on the slide. Preferably, the central aperture is mounted on the slide via a bearing, in particular a pivot bearing or rotary bearing. For example, the linear drive can be a threaded spindle or a rack and pinion. By means of the linear drive and the movable slide, the central aperture can be moved quickly and easily to the required position between the light field aperture and the aperture aperture. A pivot or rotary bearing is particularly suitable as a bearing for quickly switching between positioning the central aperture in the beam path and removing it from the beam path, allowing the central aperture to be rotated or pivoted out of the beam path.This allows, among other things, for different shots to be taken successively under different operating modes, in which operating modes the central aperture is located in the beam path or removed from it or located in different positions.

[0035] In a further preferred embodiment, at least one deflecting mirror and / or at least one beam splitter and / or several lenses are arranged in the beam path. The number of deflecting mirrors, beam splitters, and / or lenses depends on the specific application and analytical purpose. The type and arrangement of the light source can also be relevant in determining how many deflecting mirrors, beam splitters, and / or lenses are ultimately arranged in the beam path.

[0036] The light source can be, for example, a single LED or a set of LEDs. Specifically, it is an RGB LED or several RGB LEDs. Preferably, the light source comprises exactly four RGB LEDs.

[0037] As a further solution to the aforementioned problem, a microplate reader is specified, comprising a receiving device for receiving a microplate having a plurality of wells in which the samples to be analyzed can be arranged, an optical detector for detecting radiation at the individual wells of the microplate received in the receiving device, and an image generation unit for generating images of the sample in the individual wells, wherein the receiving device and / or the optical detector and / or the image generation unit are movably arranged relative to each other in order to position the received microplate with respect to the optical detector for successive measurements at different wells.

[0038] The microplate reader according to the invention is characterized in that the microplate reader comprises an illumination system as described above, particularly in an advantageous embodiment. In particular, the microplate reader comprises a microplate received in the holder.

[0039] In particular, the image generation unit is a camera or the image generation unit includes at least one camera.

[0040] Preferably, the illumination system and / or the image generation unit is movably arranged relative to the recording device and / or the optical detector. The illumination system can be positioned relative to the detector and / or the image generation unit to enable optimal measurement. Alternatively, or preferably additionally, the position of the central aperture depends on the geometry and / or the filling of the recess on the microplate. The position of the central aperture can be changed according to the geometry and / or the filling of the microplate to minimize or completely eliminate the meniscus effect.

[0041] A preferred embodiment of the microplate reader is characterized by the fact that the microplate reader comprises a control device, wherein the control device is configured to position the central aperture in the beam path via a positioning device, in particular a positioning mechanism. The central aperture can be arranged accordingly via the control device, particularly also depending on stored or predefined data relating to the microplate and / or to the samples arranged in the wells of the microplate. The positioning device can be configured as described above.

[0042] The control device includes in particular a controller, a memory, an image memory, a processor and a program.

[0043] Preferably, the control device is configured to capture multiple images at individual wells of the microplate, wherein the central aperture can be positioned differently for each image or removed from the beam path, and / or wherein the optical radiation is modified. Multiple images can be captured for individual wells via the control device, for example, to achieve optimal settings or obtain optimal image capture, or to obtain multiple images of a sample under different conditions. The arrangement of the central aperture is determined, in particular, based on stored or predefined data relating to the microplate and / or the samples arranged in the wells of the microplate.

[0044] Alternatively, or preferably additionally, the control device is designed to combine the individual images and / or parts thereof into a complete result for the respective well. In particular, the images and / or parts thereof can be combined into a single overall result that provides a complete image of the well without limitations due to the meniscus effect. This enables a better analysis of the individual wells, allowing for more precise and / or better conclusions to be drawn about the respective samples in the individual wells.

[0045] As a further solution to the aforementioned problem, a method for generating at least one image of biological or chemical samples using a microplate reader is specified, wherein the microplate reader can be designed, in particular as described above or in an advantageous embodiment thereof.

[0046] The method according to the invention comprises the following steps: V1) Receiving at least one microplate in a receiving device, wherein the microplate has a plurality of recesses in which samples are formed or arranged; V2) Positioning of the microplate relative to an image generation unit and an illumination system for emitting optical radiation and optionally to an optical detector, wherein the illumination system comprises a light source, a field aperture and an aperture aperture spaced apart from the field aperture, which are arranged along an optical axis of the optical radiation; V3) Illuminating the individual recesses with optical radiation; V4) Generating at least one image of the sample in the individual wells with the image generation unit and optionally capturing optical signals at each of the wells of the microplate with the optical detector.

[0047] The method according to the invention is characterized in that a central aperture with an aperture area with reduced transmission, in particular up to the point of preventing transmission, is arranged in the beam path of the optical radiation between the luminous field aperture and the aperture aperture.

[0048] Advantageously, the central diaphragm is moved via a positioning device, in particular a positioning mechanism. Alternatively, or preferably additionally, the central diaphragm can be inserted into or removed from the beam path. The movable nature of the central diaphragm allows images to be taken under different conditions, in particular with and without the central diaphragm in the beam path.

[0049] In a further preferred embodiment of the method, the central aperture is positioned depending on a geometry and / or a filling of the recess of the microplate.

[0050] Preferably, multiple images are taken at individual wells of the microplate for different positions of the central aperture. In particular, the individual images and / or parts thereof are combined to create a composite image for each well. This results in a composite image with an optimized representation of the individual wells.

[0051] Further advantages and features of the present invention will become apparent from the following description of an exemplary embodiment with reference to the figures. The figures show: Fig. 1 a microplate reader in schematic sectional view; Fig. 2 an embodiment of a lighting system according to the invention; Fig. 3a and Fig. 3b an embodiment of the lighting system with positioning mechanism in different positions; and Fig. 4a to 4c different embodiments of the central aperture with aperture area.

[0052] In Fig. Figure 1 shows a schematic sectional view of a microplate reader 1. The microplate reader 1 comprises a receiving device 2 by means of which a microplate 3 can be inserted into and removed from the housing of the microplate reader 1. The receiving device 2 can be designed to receive different microplates 3 or adapted accordingly.

[0053] The microplate 3 has a multitude of wells 4, in each of which individual samples are arranged or formed. For example, the microplate 3 has a total of 96 wells 4. The individual samples in the wells 4 are, for example, chemical or biological samples, which are analyzed and examined using the microplate reader 1.

[0054] To perform corresponding measurements of biological or chemical samples in the individual wells 4 of the microplate 3, the microplate reader 1 comprises at least one detector 5 for detecting the radiation absorbed, reflected, and / or scattered by the sample in the well 4 and / or the radiation emitted by the sample itself, for example, by excitation of the sample. A filter 5a, which only transmits certain wavelengths or specific wavelength ranges, can also be arranged in front of the detector 5. Furthermore, the microplate reader 1 has an image generation unit 8 for generating images of the samples in the individual wells 4 of the microplate 3, which is arranged below the recording device 2 or the microplate 3. The image generation unit 8 includes, in particular, a camera for generating corresponding images of the samples in the individual wells 4 of the microplate 3.

[0055] To capture the image of the radiation transmitted and / or scattered by the sample, it is necessary that the sample itself is illuminated or X-rayed.

[0056] For this purpose, the microplate reader 1 is equipped with an illumination system 10, which illuminates the samples in the individual wells 4 of the microplate 3 in order to capture or generate corresponding images. The illumination system 10, as well as the image generation unit 8 and the detector 5, can be moved relative to the microplate 3 or the receiving device 2, so that individual wells 4 can be measured selectively. Preferably, the microplate 3 or the receiving device is movable relative to the illumination system 10 and the detector 5, for example, by means of a positioning mechanism (not shown). For this purpose, the microplate reader 1 includes, among other things, a control device 7, by means of which the individual components of the microplate reader 1 are moved and controlled.Alternatively, the radiation within the microplate reader 1 can be deflected to the individual wells 4 by appropriate means.

[0057] Finally, the microplate reader 1 also includes an evaluation unit 6, by means of which the individual measurement results for the individual wells 4 in the microplate 3 are evaluated and analyzed. The evaluation unit 6 is part of the control unit 7 and integrated within it. In particular, however, the evaluation unit 6 can also form an independent module separate from the control unit 7.

[0058] In Fig. Figure 2 shows the illumination system 10 according to the invention, as used in a microplate reader 1. The illumination system 10 comprises a housing 11 within which a light source 12 is arranged. The light source 12 can, for example, be a single LED or a set of LEDs. In particular, it is an RGB LED or several RGB LEDs. Preferably, the light source 12 comprises exactly four RGB LEDs. The light source 12 emits radiation which propagates along a beam path 21 with a radiation cross-section within the illumination system 10 and is directed to the respective recess 4 in the microplate 3. A frosted screen (not shown) can be arranged in the beam path immediately after the light source 12, which distributes the intensity of the radiation source 12 more homogeneously.

[0059] Along the optical axis 22 in the illumination system 10, a collector lens 13 and a field diaphragm 14 with an aperture 14a are arranged downstream of the light source 12. The collector lens 13 can be a single lens or an arrangement of several lenses or a set of lenses. Further along the beam path 21, downstream of the field diaphragm 14, there is at least one further lens 15, followed by the aperture diaphragm 16 with aperture 16a. The aperture diaphragm 16 is located at a distance 23 from the field diaphragm 14. Finally, further along the beam path 21, a mirror 17 for deflecting the radiation towards the individual recesses 4 in the microplate 3 and another lens, here referred to as the focusing lens 18, are arranged. The lens 15 and the focusing lens 18 form a condenser for condenser illumination or Köhler illumination.

[0060] The present illumination system 10 further comprises a central aperture 19, which is arranged in the beam path 21 at a distance 23 between the illumination field aperture 14 and the aperture aperture 16. The central aperture 19 has a central aperture distance to the illumination field aperture 14 and is also spaced away from the aperture aperture 16, such that the central aperture 19 is arranged outside a plane of both the illumination field aperture 14 and the aperture aperture 16.

[0061] The central aperture 19 is arranged in the beam path 21 such that essentially a center of gravity or midpoint of the central aperture 19 coincides with an optical axis 22 of the optical radiation. In particular, the central aperture 19 is centered in the beam path 21 of the optical radiation. The position of the central aperture 19 between the aperture diaphragm 16 and the illumination field diaphragm 14 can be changed or varied according to requirements, or, if necessary, the central aperture 19 can also be completely removed from the beam path 21. For this purpose, the central aperture 19 is designed to be movable by means of a positioning device 25, thus allowing corresponding positioning in or removal from the beam path 21. The positioning device 25 is based on the Fig. 3a and Fig. 3b is explained in more detail in an exemplary embodiment.

[0062] In Fig. Figure 3a) shows the lighting system 10 with the positioning device 25 in a first state in which the central aperture 19 is arranged in the beam path 21 and positioned accordingly. The positioning device 25 can be an integral part of the lighting system 10 or it can be a separate unit independent of the lighting system 10. In this case, the lighting system 10 has an opening 24 in the housing 11 through which the central aperture 19 can be inserted into the beam path 21 by means of the positioning device 25. The positioning device 25 comprises a linear drive 26 in the form of a threaded spindle, on which a slide 27 is movably arranged along the direction of movement 26a of the linear drive 26. A rack and pinion can also be used instead of a threaded spindle.To move the carriage 27 along the linear drive 26, the positioning device 25 further comprises a motor 28, by means of which the carriage 27 is moved continuously or incrementally along the direction of movement 26a. For attaching the central aperture 19 to the carriage 27, the positioning device 25 further includes a holder 29, by means of which the central aperture 19 is at least indirectly arranged on the carriage 27. The holder 29 is designed as a pivot arm, which is pivotable on the carriage 27 via a bearing 30. In particular, the holder 29 can have a frame in which the central aperture 19 with its aperture area 20 is inserted.

[0063] In Fig. 3b) The lighting system 10 with the positioning device 25 is shown in a second state in which the central aperture 19 has been or is being removed from the beam path 21. In this case, the central aperture 19 is removed from the beam path by a pivoting movement. For this purpose, a bearing 30, designed as a pivot bearing, is arranged on the positioning device 25. The bearing 30 is operatively connected to the holder 29 such that the holder 29, with the central aperture 19, is pivoted in the direction of the linear drive 26 or the carriage 27. The pivoting movement is carried out in this case by moving the carriage 27 along the linear drive 26 or in the direction of movement 26a and the holder 29 hitting a stop 31 on the housing 11 of the lighting system 10, whereby the pivoting process for the holder 29 mounted on the bearing 30 is carried out by the further movement of the carriage 27 in the direction of movement 26a.Alternatively, the pivoting movement can also be performed independently of the movement of the carriage 27 along the linear drive 26, for example by means of a separate motor specifically for the pivoting movement. Another alternative, depending on the design of the bearing 30, a lateral pivoting movement can also be performed, which also allows the central aperture 19 to be removed from the beam path 21. In particular, the arrangement as shown in . Fig. As shown in 3b, it is a compact design that requires no additional space.

[0064] In Fig. Figures 4a) to 4c) show different embodiments of the central aperture 19 with its aperture area 20. Fig. Figure 4a shows a central aperture 19 with a circular aperture area 20, which completely prevents transmission of the radiation within this aperture area 20. Outside the aperture area 20, the central aperture 19 is transparent to the radiation used. The diameter of the aperture area 20 in Fig. 4a) is 2 mm in this case, but can be up to 12 mm depending on the type of application and the magnification. The magnification is essentially determined by the lens 15 and the focusing lens 18 and also depends on the diameter of the individual recess 4.

[0065] In Fig. Figure 4b) shows a further embodiment of the central aperture 19, in which the aperture area 20 has a profile with respect to transmission or a transmission coefficient, wherein the transmission and thus also the transmission coefficient increase towards the outside. In particular, this is a gradual profile. Alternatively, the profile can also have a step-shaped or parabolic progression, which also extends continuously to complete transmission.

[0066] In Fig. Figure 4c) shows a further embodiment of the central aperture with its aperture area 20, in which the central aperture 19 has an opening area 20a in the region of the optical axis 22. The opening area 20a allows the transmission of radiation even in the region of the optical axis 22. Here, the opening area 20a can be designed such that the radiation is transmitted essentially unimpeded and completely passed through. Alternatively, however, the opening area 20a can also be designed such that it at least partially prevents transmission, with the prevention of transmission in the aperture area 20 outside the opening area 20a being greater than at the opening area 20a itself.

[0067] The central aperture 19 and, in particular, the aperture area 20 can also have any other desired shape. Specifically, the aperture area 20 can be elliptical, oval, or rectangular, for example, even polygonal. Furthermore, the central aperture 19 can be a slide or, alternatively, made of glass or plastic. The aperture area 20 is located in the central aperture 19 in the Fig. 4a to 4c are achieved or formed by fixing an additional element for forming the aperture range 20 to the central aperture 19. This allows for simple and quick adjustment and, if necessary, modification of the aperture range 20. This further increases the flexibility of use. Reference symbol list 1 microplate reader 2 Recording device 3 microplate 4. Further Study 5 Detector 5a Filter 6 Evaluation unit 7 Control device 8 Image generation unit 9 10 Lighting system 11 cases 12 light sources 13 Collector lens 14 Light field cover 14a Aperture 15 lenses 16 Aperture aperture 16a Aperture 17 mirrors 18 Focusing lens 19 Central aperture 20 aperture range 20a Opening area 21 Beam path 22 optical axis 23 distance 24-hour opening 25 Positioning device 26 Linear drive 26a Direction of movement 27 sleds 28 engine 29 bracket 30 warehouses 31 attacks QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. 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

[0000] US 623911B1

[0006] DE 10 2015 111 426 B3

[0007]

Claims

[1] Illumination system (10), in particular for a microplate (3) in a microplate reader (1), with a light source (12) for emitting optical radiation which is designed within the lighting system (10) to run along a beam path (21) with an optical axis (22) and has a radiation cross-section that varies, in particular along the beam path (21), with a luminous field aperture (14) which is arranged directly or indirectly adjacent to the light source (12) and has an aperture opening (14a) for the beam path (21), with an aperture diaphragm (16) which is arranged along the optical axis (22) at a distance (23) from the luminous field diaphragm (14) and has a further aperture opening (16a) for the beam path (21), and with at least one lens which is arranged along the optical axis (22) in the beam path (21), characterized by , that a central aperture (19) can be arranged in the beam path (21) within the distance (23) of the luminous field aperture (14) and the aperture aperture (16), wherein the central aperture (19) has an aperture area (20) with reduced transmission, in particular up to the point of preventing transmission, in a region of the optical axis (22). [2] Lighting system (10) according to claim 1, characterized by , that a center of gravity of the aperture area (20) coincides with the optical axis (22), in particular that the aperture area (20) is located essentially in the middle of the radiation cross-section. [3] Lighting system (10) according to any one of the preceding claims, characterized by , that the central aperture (19) is arranged outside a plane of the aperture aperture (16) and / or the luminous field aperture (14). [4] Lighting system (10) according to any one of the preceding claims, characterized bythat a transmission coefficient of the aperture area (20) is constant over the aperture area (20) or has a profile, preferably that the transmission coefficient of the aperture area (20) has a gradual profile, in particular a transmission coefficient to be accepted towards the outside. [5] Lighting system (10) according to any one of the preceding claims, characterized by , that the aperture area (20) at least partially absorbs and / or scatters and / or reflects the radiation and / or that the aperture area (20) is structured. [6] Lighting system (10) according to any one of the preceding claims, characterized by , that the aperture area (20) is smaller than or equal to the radiation cross-section in the area of ​​the central aperture (19) and / or that the aperture area (20) has a round, oval or rectangular cross-section. [7] Lighting system (10) according to any one of the preceding claims, characterized by, that the aperture area (20) has a diameter or length of at least one principal axis or one side edge in a range of 1 mm to 12 mm, preferably in a range of 1.5 mm to 6 mm, particularly preferably of 4 mm. [8] Lighting system (10) according to any one of the preceding claims, characterized by , that an opening area is formed within the aperture area (20), in particular that the opening area lies in the area of ​​the optical axis (22), preferably that the opening area is a maximum of 50% in relation to the diameter of the aperture area (20). [9] Lighting system (10) according to any one of the preceding claims, characterized by , that the central aperture (19) is substantially transparent to radiation outside the aperture area (20) and / or that the central aperture (19) is formed from the aperture area (20) and in particular has a support that is transparent to radiation. [10] Lighting system (10) according to any of the preceding claims, characterized by , that the central aperture (19) is a slide and / or that the central aperture (19) is designed as a controllable transmission filter, in particular by means of a liquid crystal display. [11] Lighting system (10) according to any of the preceding claims, characterized by that the central aperture (19) is made of glass or plastic, wherein the aperture area (20) is an integral part of the central aperture (19) and / or the aperture area (20) is formed by an additional element on the central aperture (19), in particular that the additional element is fixed on the central aperture (19), preferably glued on. [12] Lighting system (10) according to any one of the preceding claims, characterized by, that the position of the central aperture (19) can be changed at the distance (23) from the luminous field aperture (14) and the aperture aperture (16) and / or that the central aperture (19) is designed to be removable from the beam path (21). [13] Lighting system (10) according to any one of the preceding claims, characterized by , that the central aperture (19) is designed to be movable via a positioning device (25), in particular a positioning mechanism, preferably that the positioning device (25) has an electric drive and / or a fluid power drive, in particular a hydraulic or pneumatic drive, and / or a mechanical drive. [14] Lighting system (10) according to claim 13, characterized by, that the positioning device (25) comprises a linear drive (26) and a slide (27) movable relative to and along the linear drive (26), wherein the central aperture (19) is arranged directly or indirectly on the slide (27), preferably that the central aperture (19) is arranged on the slide (27) via a bearing (30), in particular a pivot bearing or rotary bearing. [15] Lighting system (10) according to any one of the preceding claims, characterized by , that at least one mirror (17), in particular a deflecting mirror, and / or at least one beam splitter and / or several lenses are arranged in the beam path (21). [16] Microplate reader (1) with a receiving device (2) for receiving a microplate (3) which has a plurality of wells (4) in which wells (4) samples to be analyzed can be arranged, with an optical detector (5) for detecting radiation at each of the wells (4) of the microplate (3) received in the receiving device (2), and with an image generation unit (8) for generating images of the sample in the individual wells, wherein the recording device (2) and / or the optical detector (5) and / or the image generation unit (8) are arranged movably relative to each other in order to position the recorded microplate (3) with respect to the optical detector (5) and / or the image generation unit (8) for successive measurements at different wells (4), characterized by , that the microplate reader (1) comprises a lighting system (10) according to any of the preceding claims. [17] Microplate reader (1) according to claim 16, characterized by, that the illumination system (10) and / or the image generation unit (8) is arranged to be movable relative to the recording device (2) and / or the optical detector (5). [18] Microplate reader (1) according to one of the preceding claims 16 or 17, characterized by , that the position of the central aperture (19) depends on a geometry and / or a filling of the recess (4) of the microplate (3). [19] Microplate reader (1) according to any one of the preceding claims 16 to 18, characterized by , that the microplate reader (1) comprises a control device (7) and the control device (7) is designed to position the central aperture (19) in the beam path (21) via a positioning device (25), in particular a positioning mechanism. [20] Microplate reader (1) according to claim 19, characterized by, that the control device (7) is designed to take several images at each individual recess (4) of the microplate (3), wherein the central aperture (19) can be arranged at different positions for the individual images or is removed from the beam path (21) and / or wherein the optical radiation is modified. [21] Microplate reader (1) according to claim 20, characterized by , that the control device (7) is designed to combine the images and / or parts thereof into an overall result for the respective recess (4). [22] Method for producing at least one image of biological or chemical samples using a microplate reader (1), in particular in a microplate reader (1) according to any one of the preceding claims 16 to 21, comprising the steps: V1) Receiving at least one microplate (3) in a receiving device (2), wherein the microplate (3) has a plurality of recesses (4) in which samples are formed; V2) Positioning the microplate (3) relative to an image generation unit (8) and an illumination system (10) for emitting optical radiation and optionally to an optical detector (5), wherein the illumination system (10) comprises a light source (12), a field aperture (14) and an aperture aperture (16) spaced apart from the field aperture (14), which are arranged along an optical axis (22) of the optical radiation; V3) Illuminating the individual recesses (4) with optical radiation; V4) Generating at least one image of the sample in the individual wells with the image generation unit (8) and optionally detecting optical signals at each of the wells (4) of the microplate (3) with the optical detector (5); characterized by , that in the beam path (21) of the optical radiation a central aperture (19) with an aperture area (20) with reduced transmission, in particular to the point of preventing transmission, is arranged between the luminous field aperture (14) and the aperture aperture (16). [23] Method according to claim 22, characterized by , that the central aperture is moved via a positioning device (25), in particular a positioning mechanism and / or that the central aperture (19) can be inserted into or removed from the beam path (21). [24] Method according to one of the preceding claims 22 or 23, characterized by, that the central aperture (19) is positioned depending on a geometry and / or a filling of the recess (4) of the microplate (3). [25] Method according to any one of the preceding claims 22 to 24, characterized by , that several images are taken at each individual well of the microplate (3) for different positions of the central aperture (19) and / or under different optical radiation, in particular that the images and / or parts of them are combined to form an overall result for the respective well (4).

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