Attachment device for a microscope

Abstract

The invention relates to an attachment device (1) for a microscope (2), the attachment device (1) having: - a microscope connection (3) for the non-destructively releasable connecting of the attachment device (1) to a camera adapter (4) of the microscope (2), said camera adapter being provided for connecting a camera to the microscope (2) in a non-destructively releasable manner and - a camera connection (5) for the non-destructively releasable connecting of the camera to the attachment device (1) and - an optical arrangement (6) for forwarding emission light (7) entering the attachment device (1) from the microscope (2) through the microscope connection (3) to the camera connection (5), wherein the attachment device (1) has a focus-holding apparatus (8) for maintaining the focusing of the microscope (2) on a sample (9) to be viewed.

Description

[0001] attachment for a microscope

[0002] The present invention relates to an attachment for a microscope, the attachment comprising:

[0003] - a microscope connection for the non-destructively detachable connection of the attachment to a camera adapter of the microscope intended for the non-destructively detachable connection of a camera to the microscope and

[0004] - a camera connection for non-destructively detachable connection of the camera to the attachment and

[0005] - an optical arrangement for transmitting emission light entering the attachment from the microscope through the microscope connection to the camera connection.

[0006] A variety of microscopes are known to feature a camera adapter. This camera adapter allows a camera to be connected directly to the microscope.

[0007] It is also already known to provide generic attachments that enable functionalities not present in a microscope itself to be implemented using the attachment. For example, JP 2014-235332 A shows such an attachment that has an image multiplication device for multiplying an image of the sample being viewed with the microscope. The attachment shown in JP 2014-235332 A multiplies one image into two images by means of beam splitting.

[0008] The object of the invention is to equip an attachment device in such a way that it can ensure good image quality even during measurements lasting for a long time.

[0009] For this purpose, the invention proposes an attachment according to patent claim 1.

[0010] The invention therefore provides that the attachment has a focus holding device for maintaining the focus of the microscope on a sample to be viewed.

[0011] It is therefore a basic idea of ​​the invention to equip the attachment with a functionality in the form of a focus holding device, which allows the focus of the microscope on a sample to be observed to be maintained permanently. The attachment according to the invention is an additional device that can be connected to the camera adapter of the microscope, which allows the focus of the microscope on the sample to be observed to be influenced and maintained. This is particularly advantageous when long-term observations or, in other words, measurements are to be carried out with the microscope. The attachment according to the invention can also be used when it is a matter of imaging larger areas of the sample to be observed. The attachment according to the invention thus allows an additional measuring modality orAn improvement that the microscope itself may not be able to provide to prevent defocusing, i.e., a blurred image, of the sample being viewed. In other words, the attachment according to the invention also helps compensate for distortions in the measurement results or the microscope image caused by external influences such as temperature fluctuations and the like.

[0012] The attachment according to the invention has at least two connections. Firstly, there is the microscope connection, with which the attachment can be non-destructively and detachably attached to or connected to the camera adapter of the microscope. The attachment can therefore be connected with its microscope connection to the connection or camera adapter of the microscope, which is provided by the microscope manufacturer for connecting a camera. Furthermore, the attachment according to the invention also has a camera connection. This serves to attach any type of camera to the attachment in a non-destructively and detachably manner. Non-destructively detachable connections are those designed and intended to allow the attachment or camera to be mounted and removed repeatedly.Preferably, both the microscope connection and the camera connection of the attachment are designed in a way that is known in the prior art for directly connecting a camera to a microscope. Various standards that are known per se in the prior art can be used here. As an alternative to using standardized connections, it is of course also possible to develop your own microscope and / or camera connections, e.g. in the form of quick-release fasteners, for the implementation of the invention. The terms microscope connection and camera connection of the attachment as well as camera adapter of the microscope were essentially chosen to make them distinguishable from one another. The microscope connection is the connection on the attachment that is used to connect to the camera adapter of the microscope. The camera connection of the attachment is the connection that is used to connect a camera to the attachment.The same or different connection types can be used for the microscope connection and the camera connection. Connections are preferably implemented such that the microscope connection fits directly onto the camera adapter of the microscope and the camera fits directly onto the camera connection of the attachment. If this is not the case, suitable connection adapters, which are known in the art, can be used. Such connection adapters can then be inserted between the microscope connection and the camera adapter of the microscope, or between the camera connection of the attachment and the camera. The camera adapter of the microscope can usually be detached and thus interchangeably attached to the microscope using a connection adapter. This is known in the art.Alternatively, it is also conceivable that the camera adapter is fixed to the microscope and / or directly attached to the microscope, in particular to its housing.

[0013] For the sake of completeness, it should also be noted that the microscope connection, the camera connection, and the camera adapter each comprise both the mechanical means for the physical connection of the respective components involved, as well as the respective optical path for the corresponding passage of light through the corresponding connection. Thus, the microscope connection of the attachment allows, on the one hand, the mechanical attachment of the attachment to the microscope's camera adapter, and, on the other hand, the light emerging from the microscope's camera adapter to enter the attachment through the microscope connection. The same applies to the camera connection. This allows, on the one hand, the mechanical

[0014] Attaching the camera to the attachment and also allowing light to escape through the camera connection into the

[0015] Camera.

[0016] The emission light is the light generated in the microscope by the fluorescence of the excited sample or the dyes contained therein. It enters the attachment through the microscope connection and is passed on by the optical arrangement of the attachment to the camera connection of the attachment, from where it enters the camera. In other words, the emission light contains the image of the sample. The excitation of the fluorescence of the sample or the dyes contained therein can be achieved by different forms of excitation light or, in other words, by different excitation beams. As in the exemplary embodiments shown further below, it is possible to direct the excitation beam onto the sample from the side on which the emission light is also re-emitted by the sample. However, it is also possible to irradiate the sample with the excitation light to generate the emission light, or in other words, to transmit it.It is possible to integrate a light source for generating the excitation beam into a sample holder onto which the sample is placed for observation under the microscope. In all of the cases described, the excitation beam can also be directed onto the sample at different angles. For the sake of completeness, it should be noted that through appropriate filtering, reflection, deflection, and the like, the composition of the emitted light, such as the wavelength spectrum, can be changed or specifically influenced on its path through the attachment. The wavelength spectrum of the emitted light is generally in the range visible to humans.

[0017] The microscopes for which the attachments according to the invention are used, or in other words with which the attachments according to the invention are used together, are preferably inverted microscopes. In inverted microscopes, the objective lens is located below the sample.

[0018] Focus-holding devices integrated directly into microscopes are known in the prior art. For example, there is a system integrated into a microscope that projects a grating onto the sample, detects the reflection, and evaluates the changes in this grating. All of these focus-holding devices, which are known for microscopes per se, can be implemented in the attachments according to the invention, if appropriately adapted.

[0019] However, a particularly preferred form of the attachment according to the invention provides that the focus holding device has an infrared light source and an infrared light detector and a focus holding device beam splitter for forwarding an infrared light beam emitted by the infrared light source to the microscope connection and for forwarding an infrared light beam entering through the microscope connection to a detection surface of the infrared light detector. This preferred embodiment of the focus holding device of the attachment therefore provides an infrared light source and an infrared light detector in the attachment. The infrared light source generates an infrared light beam, which is radiated into the microscope through the microscope connection, then reflected in the microscope by the sample to be observed and re-enters the attachment via the microscope connection, where it then strikes the detection surface of the infrared light detector.The prerequisite, of course, is that the attachment with the microscope connection is appropriately attached to the camera adapter of the microscope.

[0020] The incoming infrared light beam could also be called the reflected infrared light beam, since it was reflected by the sample.

[0021] Preferred embodiments provide that the focus holding device beam splitter is also part of the optical arrangement for forwarding the emission light entering the attachment from the microscope through the microscope connection to the camera connection. In other

[0022] In other words, both the infrared light for the focus-holding function and the emission light for observing or imaging the sample pass through the focus-holding device beam splitter. The focus-holding device beam splitter is preferably designed such that it allows visible light, and thus also the emission light, to pass through in the direction of the camera connection of the attachment. The emission light is preferably light in a wavelength range from 450 nanometers to 700 nanometers. The infrared light of the infrared light beam from the infrared light source, on the other hand, is advantageously reflected as completely as possible by the focus-holding device beam splitter. The infrared light of the infrared light beam from the infrared light source is preferably in the wavelength range greater than 750 nanometers. State-of-the-art technology can be used for both the infrared light source and the infrared light detector.There are numerous state-of-the-art cameras or other detectors available that are sensitive to infrared light.

[0023] Preferred variants of the attachment according to the invention provide for a plano-convex lens to be arranged between the microscope connection and the focus-holding device beam splitter, and a concave lens to be arranged between the infrared light source and the focus-holding device beam splitter. The position of the concave lens relative to the plano-convex lens can be adjusted by means of a concave lens adjustment element of the focus-holding device. By changing the distance between the concave lens and the plano-convex lens, the infrared light of the focus-holding device can be optimally focused into a rear focal plane of the microscope objective.

[0024] Preferred variants of the attachment according to the invention can also provide for the position of the infrared light source relative to the detection surface of the infrared light detector to be adjustable by means of an infrared light source adjusting element of the focus holding device. This adjustability of the relative position between the infrared light source and the detection surface of the infrared light detector can ensure that sufficient or as much infrared light as possible is reflected by the sample and then also strikes the detection surface of the infrared light detector. If possible, the distance between the infrared light source and the detection surface of the infrared light detector is adjusted so that total reflection of the infrared light occurs at the sample. This

[0025] The adjustment option using the infrared light source control element serves to ensure that enough infrared light is returned from the sample and applied to the

[0026] The infrared light source is preferably moved relative to the detection surface of the infrared light detector using the infrared light source adjustment element. However, the adjustment can also be implemented the other way around. Furthermore, it is of course also possible to move both the infrared light source and the detection surface to adjust their relative positions to each other using the infrared light source adjustment element.

[0027] It should be noted that both the concave lens adjusting element and the infrared light source adjusting element, as well as all of the adjusting elements mentioned below, can be designed very differently. They can be purely mechanical, preferably manually operated adjusting elements. Of course, they can also be motor-driven adjusting elements that can be controlled via a corresponding input element. There are numerous possibilities for this in the prior art, which can be used accordingly to implement the invention. In order to be able to remove any infrared light still present behind the focus holding device beam splitter from the emission light, preferred embodiments of the attachment can provide for an infrared light filter of the attachment to be arranged on the side of the focus holding device beam splitter facing away from the microscope connection in order to filter out infrared light from the emission light.The infrared light filter can therefore be used to prevent infrared light from being transmitted to the camera as interference.

[0028] Particularly preferred embodiments of the invention provide that the focus holding device has a control device and a trigger element, wherein the control device is configured to, upon actuation of the trigger element, control the position of the object on the detection surface of the

[0029] To determine the incoming infrared light beam incident on the infrared light detector as the target position and, in the event of a subsequent shift in the position of the incoming infrared light beam on the detection surface from the target position, to output a control signal for a control actuator to maintain the focus of the microscope on the sample to be viewed in order to return the incoming infrared light beam on the detection surface to the target position.

[0030] A method for operating such a focus holding device can therefore provide that the control device, upon actuation of the trigger element, determines the position of the incoming infrared light beam striking the detection surface of the infrared light detector as the target position and then, upon a subsequent shift of the position of the incoming infrared light beam on the detection surface from the target position, the control device outputs a control signal for a control actuator to maintain the focus of the microscope on the sample to be observed in order to return the incoming infrared light beam on the detection surface to the

[0031] to return to the target position.

[0032] The actuator can be part of the focus holding device. For example, it is possible for the actuator to be a component that drives or controls a corresponding objective adjustment element of the microscope. Alternatively, the actuator can also be integrated into the microscope, e.g., as a piezo element or a servo motor, in order to directly move or adjust an objective of the microscope. Regardless of how this is specifically designed, it is preferably provided that the actuator is used for

[0033] To maintain the focus of the microscope on the sample to be viewed, the position of an objective lens of the microscope can be adjusted relative to the sample to be viewed.

[0034] In addition to the focus-holding device, further functionalities can also be implemented in the attachment according to the invention. For example, it is possible for the optical arrangement for transmitting emission light entering the attachment from the microscope through the microscope port to the camera port to include an image multiplication device for multiplying, preferably doubling, an image of the sample to be viewed. Such image multiplication devices are known per se and can be integrated into attachments according to the invention in various embodiments.

[0035] Preferred variants provide that the image multiplication device has an image multiplication beam splitter for splitting the emission light into at least two different beam paths.

[0036] It is also possible to filter the images of the sample to be observed generated with the image multiplication device differently. In this context, preferred variants of the invention provide for an emission light filter to be arranged in at least one of the beam paths, preferably in each of the beam paths, preferably with different emission light filters being arranged in the beam paths. In order to be able to achieve different types of image multiplication and filtering in a simple manner using the same attachment, preferred embodiments of the invention provide for the image multiplication beam splitter and the emission filter(s) to be designed as an interchangeable assembly arranged in the attachment.By combining the emission filters and the image multiplication beam splitter into one assembly, they can be quickly and easily replaced together so that images filtered in a different way can subsequently be generated using the attachment.

[0037] It is also advantageous if the image multiplication device has a knife-edge prism for deflecting the beam paths toward the camera connection. The knife-edge prism has the advantage that even deflected beam paths at its edges are still cleanly deflected by the sharp edges of the knife-edge prism, and no or minimal scattering effects occur. It is also particularly advantageous in this context if a focusing lens is placed upstream of the knife-edge prism in at least one of the beam paths, preferably in each of the beam paths. The knife-edge prism could also be referred to in German as a sharp-edged deflection prism.

[0038] Preferred embodiments provide for the image multiplication device to also have an operating mode in which only a single image is forwarded to the camera port. This operating mode can be adjusted, for example, by shifting the knife-edge prism so that only one beam path reaches the camera port, as will be illustrated below. Further features and details of preferred embodiments of attachments according to the invention are explained below with reference to the description of the figures. They show:

[0039] Fig. 1 is a highly schematic representation of a first embodiment of an attachment according to the invention, which is connected to a microscope, which is also shown highly schematically;

[0040] Figs. 2 and 3 are schematic representations for explaining the operation of the focus holding device of the embodiment shown in Fig. 1;

[0041] Fig. 4 is a schematic representation of a second embodiment of an attachment according to the invention, which is also connected to a microscope and

[0042] Fig. 5 shows the embodiment of Fig. 4, wherein the knife-edge prism of the image multiplication device is shifted so that only one beam path in the image multiplication device is guided to the camera termination.

[0043] Fig. 1 initially shows a highly schematic representation of a microscope 2 which has a camera adapter 4. This camera adapter 4 is provided by the manufacturer of the microscope 2 for the direct connection of a known camera. When using the attachment 1 according to the invention, which is also shown schematically in Fig. 1, this camera adapter 4 is used to connect the attachment 1 with its microscope connection 3 to the microscope 2. In this sense, the microscope connection 3 is the microscope-side connection of the attachment 1. As already explained at the beginning, the microscope connection 2 and the camera adapter 4 can be designed according to various standards known from the state of the art for cameras, but also in self-developed designs. The microscope connection 3 and the camera adapter 4 serve, on the one hand, to mechanically connect the attachment 1 to the microscope 2.On the other hand, the emission light 7, also coming from the microscope 2, is fed through the camera adapter 4 and the microscope connection 3 into the attachment 1 or into its optical arrangement 6. Furthermore, the infrared light rays 13 emitted by the infrared light source 10 (explained below) and the infrared rays 14, which re-enter the attachment 1 and are reflected by the sample 9 to be observed, pass through the camera adapter 4 and the microscope connection 3.

[0044] In this first exemplary embodiment shown in Fig. 1, the camera adapter 4 is fixedly attached to the housing of the microscope 2. This is a rather special case. Typically, the camera adapter 4 is detachably and thus replaceably attached to the microscope 2 by means of a connection adapter 52, as shown by way of example in Figs. 4 and 5. This replaceable solution can, of course, also be implemented in this first exemplary embodiment shown in Fig. 1.

[0045] The camera connection 5 is also located on the attachment 1.

[0046] This serves to enable a camera, not shown here but known per se in the prior art, to be detachably connected to the attachment 1 in a non-destructive manner. Deviating from the design known per se in the prior art, in which the camera is connected directly to the camera adapter 4 of the microscope 2, one can thus also speak of the attachment 1 according to the invention being interposed between the camera adapter 4 of the microscope 2 and the camera.

[0047] Located within the attachment 1 is the optical arrangement 6, which is explained in more detail below for this exemplary embodiment and which serves to transmit the emission light 7 entering the attachment 1 from the microscope 2 through the microscope connection 3 to the camera connection 5.

[0048] According to the invention, in this first embodiment according to Fig. 1, the attachment 1 has a focus holding device 8 for maintaining the

[0049] Focusing of the microscope 2 on a sample 9 to be observed. The structure and function of the focus holding device 8 implemented here will now be explained in more detail.

[0050] As already explained above, in this preferred embodiment, the focus holding device 8 comprises an infrared light source 10 and an infrared light detector 11, as well as a focus holding device beam splitter 12. This beam splitter serves, on the one hand, to direct the infrared light beam 13 emitted by the infrared light source 10 to the microscope connection 3. Furthermore, the focus holding device beam splitter 12 also ensures that the infrared light beam 14 entering through the microscope connection 3 is directed to the detection surface 15 of the infrared light detector 11. In the embodiment implemented here, the focus holding device beam splitter 12 is designed to reflect the infrared light beams 13 and 14, as shown in Fig. 1.Furthermore, it can be clearly seen that the focus-holding device beam splitter 12 is also part of the optical arrangement 6 in that it forwards the emission light 7 entering the attachment 1 from the microscope 2 through the microscope connection 3 to the camera connection 5. The focus-holding device beam splitter 12 is designed in such a way that it transmits the emission light 7 in the visible wavelength range, while it filters the infrared light of the infrared light beams 13 and.

[0051] 14, as explained.

[0052] As explained at the beginning, known devices can be used to design the infrared light source 10 and the infrared light detector 11.

[0053] A plano-convex lens 16 is located between the microscope port 3 and the focus-holding device beam splitter 12. A concave lens 17 is located between the infrared light source 10 and the focus-holding device beam splitter 12. In this preferred embodiment of the invention, the position of the concave lens 17 relative to the plano-convex lens 16 is adjustable by means of the concave lens adjusting element 18 of the focus-holding device 8.

[0054] As explained at the beginning, this concave lens adjusting element 18, like all adjusting elements explained below, can be a mechanically or motor-operated adjusting element. There are a variety of options for the design of the respective operating element, which are known per se in the prior art and can also be implemented here. There are, of course, various options for adjusting the position of the concave lens 17 relative to the plano-convex lens 16. Both the concave lens 17 and the piano-convex lens 16 can be moved. Of course, both lenses can also be moved. In the embodiment shown here in Fig. 1, only the concave lens 17 is moved back and forth along the emitted infrared light beam 13 between the infrared light source 10 and the focus-holding device beam splitter 12 by means of the concave lens adjusting element 18.As already explained at the beginning, this adjustment option serves to focus the infrared light into a rear focal plane of the objective 25 of the microscope 2.

[0055] In order to ensure, as already explained at the beginning, that enough infrared light reaches the detection surface 15 of the infrared light detector 11 with the incoming infrared light beam 14, this exemplary embodiment of an attachment 1 according to the invention as shown in Fig. 1 also provides for the position of the infrared light source 10 relative to the detection surface 15 of the infrared light detector 11 to be adjustable by means of an infrared light source adjusting element 19 of the focus holding device 8. This preferably makes it possible, as is also implemented here, to change the distance between the infrared light source 10 and the detection surface 15 of the infrared light detector 11. This can in turn be implemented such that both the infrared light source 10 and the detection surface 15 can be moved. However, it is also sufficient to move only one of these components in order to implement the required relative movement with the infrared light source adjusting element 19.By adjusting the relative position of the infrared light source 10 and the detection surface 15, it is possible to ensure the most total reflection of the infrared light possible on the sample 9 to be observed in the microscope 2.

[0056] In the embodiment shown here, a focus lens 46 is provided on the detection surface 15 for focusing the incoming infrared light beam 14. However, this focus lens 46 is optional and can be omitted if necessary.

[0057] On the side of the focus holding device beam plate 12 facing away from the microscope connection 3, there is preferably an infrared light filter 20, as also realized in this exemplary embodiment. This filter filters out infrared light components that were not reflected by the focus holding device beam splitter 12 from the beam path of the emission light 7, so that they do not interfere with the image recorded by the camera.

[0058] Directly behind the microscope connection 3, preferred embodiments of attachments 1, as implemented here, have a rectangular aperture 36 through which both the emission light 7 and the infrared light beams 13 and 14 pass. This rectangular aperture 36 can, as is known per se, be adjustable in order to adjust the image section.

[0059] Before the functioning of the focus holding device 8 of this embodiment according to Fig. 1 is explained, a brief explanation of the components of the microscope 2 shown here follows. As already explained, this is a microscope according to the prior art, so that only the components necessary for understanding the invention are shown and explained here. The microscope 3 comprises a sample holder, known per se but not shown in detail here, for the sample 9 to be observed and the objective 25, which is arranged upstream of the sample holder or the sample 9. The distance between the objective 25 and the sample 9 or the sample holder can be adjusted by means of the objective adjustment element 45, which is known per se.The lens adjustment element 45 can be a mechanical adjustment knob, as shown here, but also a motorized drive with a corresponding control element for the relative movements of the lens 25 relative to the sample 9 or the sample holder. The light required to image the sample 9 is coupled via the excitation beam 42 from a light source (not shown here) through the coupling beam splitter 43 and guided to the sample 9. The light reflected there is guided as emission light 7 through the coupling beam splitter 43 via the microscope mirror 44 and the tube lens 47 to the camera adapter 4 and thus to the attachment 1. By actuating the lens adjustment element 45 and thus by changing the distance between the lens 25 and the sample 9 to be viewed, the operating personnel can focus the image of the sample 9 in a conventional manner.

[0060] The path of the emitted infrared light beam 13 and the incoming infrared light beam 14 within the microscope 1 is also shown in Fig. 1. Ultimately, it is important that the infrared light of the emitted infrared light beam 13 is reflected by the sample 9 to be observed and, as the incoming infrared light beam 14, reaches the detection surface 15 of the infrared light detector 11 in the manner already described.

[0061] The focus holding device 8 of the embodiment in Fig.

[0062] 1 comprises a control device 21 with a trigger element 22 for carrying out the method described below. The trigger element 22 can be a simple push button, but also keys on a keyboard, control surfaces on a touchpad, or the like. The prior art provides a variety of possible configurations for this trigger element 22.The control device 21 is in any case configured to determine the position of the incoming infrared light beam 14 impinging on the detection surface 15 of the infrared light detector 11 as the target position 23 upon actuation of the trigger element 22. Upon a subsequent shift in the position of the incoming infrared light beam 14 on the detection surface 15 from the target position 23, the control device 21 is configured to output a control signal for the control actuator 24 to maintain the focus of the microscope 2 on the sample 9 to be observed, in order to return the incoming infrared light beam 14 on the detection surface 15 to the target position 23. In the present case, according to the embodiment in Fig. 1, the control actuator 24 is part of the focus holding device 8.The actuator 24 is a servomotor that accesses the lens adjustment element 45 to adjust the distance between the lens 25 and the sample 9 to be viewed in order to focus the image. Thus, the actuator 24 can be used to adjust the position of the lens 25 of the microscope 2 relative to the sample 9 to be viewed in order to maintain the focus of the microscope 2 on the sample 9 to be viewed.

[0063] When operating the microscope 2 and using the focus holding device 8 according to the invention of the attachment 1, the procedure can be as follows: First, the operating personnel focuses the image by means of the lens adjustment element 45 by correspondingly adjusting the positions of the lens 25 relative to the sample 9, as is customary in the prior art. Subsequently, the inventive method for operating the attachment 1 or its focus holding device 8 begins. When the operating personnel actuates the trigger element 22, the control device 21 determines the position of the incoming infrared light beam 14 striking the detection surface 15 of the infrared light detector 11 as the target position 23. If, for example,If, due to thermal influence or the like, defocusing and thus a shift in the position of the incoming infrared light beam 14 on the detection surface 15 from the target position 23 occurs, the control device 21 outputs a control signal for the control actuator 24 to maintain the focus of the microscope 2 on the sample 9 to be observed. By appropriately actuating the lens adjustment element 45 by means of the control actuator 24, the incoming infrared light beam 14 on the detection surface 15 is then automatically returned to the target position 23 by moving the lens 25 back to a corresponding distance from the sample 9 to focus the image.In this way, the focus on the sample 9 can be automatically and permanently ensured by means of the focus holding device 8 of the attachment 1, without additional manipulation of the lens adjustment element 45 by the operating personnel being necessary. In this way, the focus can be permanently maintained even under changing conditions, such as changing temperature influences and the like. For a further explanation of this process, reference is made to Figs. 2 and 3. Fig. 2 shows, on the one hand, the infrared light source 10 and the detection surface 15 of the infrared light detector 11, the focus holding device 8 and, on the other hand, a schematic illustration in the area of ​​the lens 25 and the sample 9 to be observed. The sample holder on which the sample 9 lies is again not shown. The area lying between these sections is not shown, but is represented schematically by the interrupted area 53.

[0064] Fig. 2 shows a schematic example of what happens when the distance between sample 9 and objective 25 changes, e.g. due to thermal influences. The sample 9 is shown in Fig. 2 in a first sample plane 48 and, for example, offset in a second sample plane 49, which is closer to the objective 25. At the start of the measurements or the observation of the sample 9 through the microscope 2, the sample 9 can be located, for example, in the first sample plane 48. The distance between sample 9 and objective 25 is then adjusted by the operating personnel using the objective adjustment element 45 so that a focused image of the sample 9 is produced in the camera. The trigger element 22 is then actuated and the position of the incoming infrared light beam 14 striking the detection surface 15 of the infrared light detector 11 is determined as the target position 23. If defocusing occurs over time, e.g.due to thermal expansion of the sample holder (not shown here), in this example comes to lie in the second sample plane 49, and thus to a change in the distance between the sample 9 and the objective 25, the incoming infrared light beam 14 no longer strikes the detection surface 15 at the target position 23 but at a different point of impact 50, as shown schematically in Fig. 2 in the plan view of the detection surface 15, the point of impact 50 is then located at a distance 51 outside the target position 23. In order to correct this, the control device 21 of the focus holding device 8 then outputs a control signal to the control actuator 24, so that the focus on the sample 9 is restored by repositioning the objective 25.This becomes apparent to the control device 21 because the current point of incidence 50 of the incoming infrared light beam 14 is returned to the target position 23. If this is the case, optimal focusing is restored.

[0065] The exemplary embodiment of an attachment 1 according to the invention shown in Fig. 1 and its optical arrangement 6 not only comprises the focus holding device 8 described so far but also an image multiplication device 26. This is advantageous, but of course does not have to be implemented in this way. The image multiplication device 26, which will now be explained with reference to Fig. 1, serves to multiply, for example to double, an image of the sample 9 to be observed. In the exemplary embodiment shown, the image multiplication device 26 is located behind the infrared light filter 20 with regard to the path of the emission light 7. It comprises an image multiplication beam splitter 27, which splits the emission light, in this exemplary embodiment into two different beam paths 28 and 29. In each of these beam paths 28 and 29, an emission light filter 30 or 31 is located behind the image multiplication beam splitter 27. These emission light filters 30 or31 can be similar or different from each other. For example, they can be transparent to different wavelength ranges and / or polarizations of light, or the like.

[0066] In the exemplary embodiment shown here, it is provided, by way of example, that the image multiplication beam splitter 27 and the emission filters 30 and 31 are designed as an interchangeable assembly 32 arranged in the attachment 1. This has the advantage that the respective assembly 32 is easy to replace, e.g. in order to achieve different effects in beam paths 28 and 29 and the images generated therefrom. The light is guided along the beam paths 28 and 29 via the highly reflective mirrors 37 to the knife-edge prism 33. There, the beam paths 28 and 29 are aligned parallel to one another and fed via the deflecting mirror 40 to the camera connection 5 of the attachment 1 and the camera connected to it (not shown here), so that the camera can record the two separate images of the beam paths 28 and 29. In contrast to the exemplary embodiment shown here, more than two beam paths 28 and 29 can of course also be implemented.

[0067] It is also advantageous if a focusing lens 34 is arranged upstream of the knife-edge prism 33 in each of the beam paths 28 and 29. In the embodiment shown here in Fig. 1, there is a focusing lens adjusting element 35 for each focusing lens 34, with which the distance between the knife-edge prism 33 and the respective focusing line 34 can be adjusted. In addition, there is also a mirror adjusting element 38 or 39 for each focusing lens 34, together with the adjacent highly reflective mirror 37, with which the area of ​​incidence of the respective beam path 28 or 29 on the knife-edge prism 33 can be adjusted. The position of the deflecting mirror 40 relative to the camera connection 5 can be adjusted using the deflecting mirror adjusting element 41.The deflecting mirror adjustment element 41 thus serves to align the images that hit the camera through the camera connection 5, centering them as much as possible in the camera connection 5. The mirror adjustment elements 38 and 39 can be used to adjust the distance between the beam paths 28 and 29 impinging on the deflecting mirror 40, and thus the distance between the images on the camera. The focusing lens adjustment elements 35 can be used to achieve appropriate focusing by adjusting the position of the respective focusing lens 34.

[0068] The exemplary embodiment shown in Fig. 4 is explained below. It is largely constructed in the same way as the exemplary embodiment shown in Fig. 1, so only the differences will be discussed below. Otherwise, please refer to the descriptions for Fig. 1.

[0069] A first difference from the first embodiment is that the actuating actuator 24 in this embodiment (see Fig. 4) does not access the objective adjustment element 45, but is designed as a component that is permanently installed in the microscope 2 or can be removed non-destructively, e.g. by means of a screw connection. In this embodiment, the actuating actuator 24 is an additional piezoelectric actuating element with which the distance between the objective 25 and the sample 9 can be finely adjusted in order to maintain the focus. The operation of the focus holding device 8 therefore does not change much compared to the first embodiment. Here, too, the operating personnel first performs the focusing using the objective adjustment element 45.If the trigger element 22 is then activated by the operating personnel, the control device 21 determines the target position 23 in the manner described for the first embodiment and then maintains the focusing of the microscope 2 on the sample 9 to be observed in the manner described, wherein the actuating actuator 24, which receives and converts the actuating signals from the control device 21, is integrated here in the form of the piezoelectric actuating element in the microscope 2 and carries out the fine positioning of the objective 25 relative to the sample 9.

[0070] A second difference between the exemplary embodiment in Fig. 4 and the exemplary embodiment in Fig. 1 is that here the camera adapter 4 is not fixedly formed on the microscope 2 as in the first exemplary embodiment, but rather, as is usual in the prior art, is part of an exchangeable connection adapter 52 which can be exchangeably attached to the microscope 2. This is often implemented by microscope manufacturers in this way so that different camera adapters 4 can be provided for different types of cameras. Even with this implementation of the camera adapter 4 using the connection adapter 52, the attachment 1 with its microscope connection 3 can be attached to the camera adapter 4 in the same way as was already described for the first exemplary embodiment.

[0071] Fig. 5 shows the embodiment from Fig. 4. Fig. 5 illustrates the operating mode in which only a single image is forwarded to camera port 5. In this example, this is achieved by a corresponding displacement of the knife-edge prism 33, so that the beam path 29 is deflected past the deflection mirror 40 and thus no longer hits the camera attached to camera port 5. In this case, only one image is forwarded to the camera attached to camera port 5.

[0072] Of course, by shifting the knife-edge prism 33 accordingly, the ray path 28 can be masked out and only the ray path 29 can be recorded.

[0073] Key to the reference numbers:

[0074] 1 attachment 26 image multiplication

[0075] 2 microscope device

[0076] 3 Microscope connection 27 Image multiplication

[0077] 4 camera adapter beam splitter

[0078] 5 Camera connection 28 Beam path

[0079] 6 optical arrangement 29 beam path

[0080] 7 Emission light 30 Emission light filter

[0081] 8 Focus holding device 31 Emission light filter

[0082] 9 Sample 32 Assembly

[0083] 10 Infrared light source 33 Knife-edge prism

[0084] 11 Infrared light detector 34 Focusing lens

[0085] 12 Focus holding device 35 Focusing lens beam splitter actuator

[0086] 13 emitted infrared 36 rectangular aperture light beam 37 highly reflective

[0087] 14 entering mirror

[0088] Infrared light beam 38 mirror actuator

[0089] 15 Detection area 39 Mirror actuator

[0090] 16 plano-convex lenses 40 deflecting mirrors

[0091] 17 Concave lens 41 Deflecting mirror -

[0092] 18 Concave lens adjusting element

[0093] Control element 42 excitation beam

[0094] 19 infrared light sources - 43 coupling beam splitters

[0095] Control element 44 microscope mirror

[0096] 20 Infrared light filter 45 Lens adjustment element

[0097] 21 Control device 46 Focus lens

[0098] 22 Release element 47 Tube lens

[0099] 23 Target position 48 first sample level

[0100] 24 Actuator 49 second sample level

[0101] 25 Lens 50 Point of impact 51 Distance

[0102] 52 connection adapters

[0103] 53 Interrupted area

Claims

Patent claims 1. An attachment (1) for a microscope (2), the attachment (1) comprising: - a microscope connection (3) for the non-destructively detachable connection of the attachment (1) to a camera adapter (4) of the microscope (2) provided for the non-destructively detachable connection of a camera to the microscope (2), and - a camera connection (5) for non-destructively detachable connection of the camera to the attachment (1) and - an optical arrangement (6) for transmitting emission light (7) entering the attachment (1) from the microscope (2) through the microscope connection (3) to the camera connection (5) , characterized in that the attachment (1) has a focus holding device (8) for maintaining the focus of the microscope (2) on a sample (9) to be observed.

2. Attachment (1) according to claim 1, wherein the focus holding device (8) comprises an infrared light source (10) and an infrared light detector (11) and a focus holding device beam splitter (12) for forwarding an infrared light beam (13) emitted by the infrared light source (10) to the microscope connection (3) and for forwarding an infrared light beam (13) emitted by the infrared light beam (14) entering the microscope connection (3) towards a detection surface (15) of the infrared light detector (11).

3. Attachment (1) according to claim 2, wherein the focus-holding device beam splitter (12) is also part of the optical arrangement (6) for forwarding the emission light (7) entering the attachment (1) from the microscope (2) through the microscope connection (3) to the camera connection (5).

4. Attachment device (1) according to claim 2 or 3, wherein a plano-convex lens (16) is arranged between the microscope connection (3) and the focus holding device beam splitter (12) and a concave lens (17) is arranged between the infrared light source (10) and the focus holding device beam splitter (12), wherein the position of the concave lens (17) relative to the plano-convex lens (16) is adjustable by means of a concave lens adjusting element (18) of the focus holding device (8).

5. Attachment (1) according to one of claims 2 to 4, wherein the position of the infrared light source (10) relative to the detection surface (15) of the infrared light detector (11) is adjustable by means of an infrared light source adjusting element (19) of the focus holding device (8).

6. Attachment (1) according to one of claims 2 to 5, wherein on the side of the focus holding device beam splitter (12) facing away from the microscope connection (3) there is an infrared light filter (20) of the attachment (1) for filtering out infrared light from the emission light (7) is arranged.

7. Attachment (1) according to one of claims 2 to 6, wherein the focus holding device (8) has a control device (21) and a trigger element (22), wherein the control device (21) is configured, upon actuation of the trigger element (22), to determine the position of the incoming infrared light beam (14) impinging on the detection surface (15) of the infrared light detector (11) as the target position (23) and, upon a subsequent displacement of the position of the incoming infrared light beam (14) on the detection surface (15) from the target position (23), to output an actuating signal for an actuating actuator (24) for maintaining the focus of the microscope (2) on the sample (9) to be observed in order to return the incoming infrared light beam (14) on the detection surface (15) to the target position (23).

8. Attachment (1) according to claim 7, wherein the actuating actuator (24) is part of the focus holding device (8).

9. Attachment device (1) according to claim 7 or 8, wherein a position of an objective (25) of the microscope (2) relative to the sample (9) to be observed can be adjusted with the actuating actuator (24) in order to maintain the focus of the microscope (2) on the sample (9) to be observed.

10. Attachment (1) according to one of claims 1 to 9, wherein the optical arrangement (6) for forwarding emission light (7) entering the attachment (1) from the microscope (2) through the microscope connection (3) to the camera connection (5) comprises an image multiplication device (26) for multiplication, preferably duplication, of an image of the sample (9) to be viewed.

11. Attachment (1) according to claim 10, wherein the Image multiplication device (26) a Image multiplication beam splitter (27) for splitting the emission light (7) into at least two different beam paths (28, 29).

12. Attachment (1) according to claim 11, wherein an emission light filter (30, 31) is arranged in at least one of the, preferably in each of the, beam paths (28, 29), preferably wherein different emission light filters (30, 31) are arranged in the beam paths (28, 29).

13. Attachment (1) according to claim 11 and 12, wherein the image multiplication beam splitter (27) and the emission filter(s) (30, 31) are designed as an assembly (32) arranged replaceably in the attachment (1).

14. Attachment (1) according to one of claims 10 to 13, wherein the image multiplying device (26) has a knife-edge prism (33) for deflecting the beam paths (28, 29) in the direction of the camera connection (5).

15. Attachment (1) according to claim 14, wherein in at least one of the, preferably in each of the, beam paths (28, 29) a focusing lens (34) is arranged upstream of the knife-edge prism (33).

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