Microscope and method for controlling it

Abstract

Method for controlling a microscope with a zoom optic for continuously adjusting the magnification by the motorized displacement of at least one first optical element of the zoom optic along an optical axis relative to at least one second optical element of the zoom optic, and with an objective turret (2) with at least two objectives (3, 4) of different magnifications, wherein when switching to an objective (3, 4) with a higher or higher magnificationAt a lower magnification, at least one first optical element is shifted by a path length determined on the basis of the objective data and the data of the zoom optics until the same magnification is set for an observer as before the switching, characterized in that, for a given magnification, it is determined on the basis of the objective data for which of the objectives (3, 4) a maximum aperture and / or a maximum depth of field and / or a minimum vignetting is achieved at this magnification, this is signaled to an observer and a change of objective is suggested, and when the suggested objective (3, 4) is selected, the given magnification is set.

Description

[0001] The invention relates to a method for controlling a microscope with a zoom optic for continuously adjusting the magnification by the motorized displacement of at least one first optical element of the zoom optic along an optical axis relative to at least one second optical element of the zoom optic, and with an objective turret with at least two objectives of different magnifications. The invention also relates to a microscope with such a zoom optic in which this control is implemented.

[0002] Modern stereomicroscopes, such as the "Discovery.V12" or the "Discovery.V20" from Carl Zeiss Micromicrographs GmbH, feature a motorized pan-axis microscope body, i.e., a microscope body with zoom optics, to which an objective lens is attached at the bottom and a binocular tube at the top. The magnification, or zooming, is adjusted by means of lenses within the zoom optics—the first optical elements—which are adjustable along the optical axis. The second optical elements, the other set of lenses, are fixed in position within the zoom optics and thus within the microscope body. For maximum precision, the adjustment of the first optical elements relative to the second optical elements is achieved using stepper motors. This allows for stepless magnification adjustment.

[0003] In high-quality stereomicroscopes, focusing at varying magnifications is motorized. This is achieved by adjusting the microscope body, with its attached objective and binocular tube, along the z-direction perpendicular to the stage plane in which the specimen is located. The zoom factor, i.e., the factor of the afocal system by which the total magnification of the objective, tube, and eyepiece must be multiplied, is 12x and 20x for the two microscopes mentioned above.

[0004] To achieve adjustment during focusing, the microscope body is mounted on a column—also known as a stand—and is motorized for adjustment in the z-direction. This column features, among other things, a profiled guide that, in conjunction with the motor and corresponding drive elements engaging with the guide's profiles, allows for height adjustments of up to approximately 30 cm in increments of just a few hundred nanometers. These profiled guides have stops at the top and bottom to limit the z-direction adjustment.

[0005] The zoom optics also have stops to limit the adjustment of the first optical elements. If there are multiple such first optical elements, the upper and lower stops are set uniformly for all of them. This means that the first optical element that reaches a stop first defines the stop for all the others, preventing them from moving further in that direction. If, during continuous zooming, at least one first optical element reaches its lower or upper stop, lower or higher magnifications can be switched by changing the objective lens, provided the microscope is equipped with a turret with multiple objectives of different magnifications. High-quality stereoscopes typically feature two- or three-position objective changers.

[0006] Corresponding zoom devices can be used not only in stereo microscopes, but of course also in normal microscopes and macroscopes.

[0007] Although stereo microscopes in particular are designed to be very user-friendly and offer many setting options, the combination of zoom optics with interchangeable lenses does have some disadvantages – albeit minor ones – that limit ease of use.

[0008] The lenses for the objective turret are generally selected so that their magnifications overlap, taking the zoom factors into account. If a lower or higher magnification is then changed at the lower or upper limit of the zoom optics, or even in the middle, by switching to a different lens on the objective turret, an observer looking through the eyepiece, or viewing a corresponding image captured by a camera on a monitor, will experience a jump in magnification.A sudden change in magnification; the observer sees the same central image area, but at a different magnification. This is particularly noticeable if, for example, one is also interested in the peripheral areas visible at the lower magnification, since the final area of ​​investigation within the sample has not yet been determined. These peripheral areas are no longer within the field of view when switching to a higher magnification. The reason for this is that, with the same zoom setting—that is, the same arrangement of lenses in the microscope body—objectives with different focal lengths / magnifications will produce correspondingly different visible image areas.

[0009] When the magnification is reduced, i.e., when the image is continuously zoomed out on the object, vignetting can occur in the eyepiece or on the monitor of stereomicroscopes due to their optical design, which is generally based on the telescope principle and uses off-axis beam pairs to generate the stereo angle. If an observer then switches to the next lower magnification objective in order to subsequently zoom back up to the same overall magnification to avoid vignetting, there is initially a jump in magnification when switching objectives.

[0010] Finally, due to the overlapping magnification ranges, the same overall magnification can be achieved for various combinations of lenses with zoom system settings. However, there is always a combination optimized for maximum aperture or maximum depth of field, meaning that these system parameters are optimal for the given selection. The observer is usually unaware of this optimal combination, so—depending on the required accuracy and observation scenario—they may not have chosen the optimal setting for observing their sample.

[0011] WO 2010 / 038 846 A1 describes a method for controlling a microscope where the aim is to maintain the overall magnification when switching between two objectives, both of which are arranged in an objective turret. During the objective change, the positions of the zoom elements – which are known – are adjusted accordingly by a motor.

[0012] German patent DE 102 14 191 A1 describes a microscope system which can electronically control the magnification, whereby in particular the magnification of an image displayed on a screen can be changed continuously and without jumps.

[0013] The object of the invention is therefore to further develop a microscope of the type described above and a method for controlling such a microscope in such a way that the magnification jumps described above are no longer negatively noticeable to the viewer or can even be avoided, thus increasing ease of use.

[0014] This problem is solved by a method of the type described above, whereby, when switching to a lens with higher or lower magnification, at least one first optical element is shifted by a path length determined based on the data of the zoom optics and the lens data, until the same magnification is set for an observer as before the switch. In this way, the magnification jump during lens changes can be avoided or is automatically compensated for in a very short time, without requiring any intervention from the operator. Continuous zooming is thus possible even when changing lenses.

[0015] The calculation of the required adjustment path takes into account the data of the objective lens – especially its magnification – the current focus setting, and the data of the zoom optics – the properties of the lenses and their alignment along the optical axis. The latter is already internally available in the aforementioned Carl Zeiss microscopes, for example, because the microscope bodies are individually manufactured and the control system is adapted to the specific properties of the lenses used for the zoom optics in each microscope body.

[0016] This resetting to the same magnification as before switching is generally possible at any magnification and focus setting, especially at both the upper and lower limits, provided the magnification ranges of the lenses involved overlap. Otherwise, the next most suitable magnification can be set.

[0017] In a preferred embodiment of the method, during continuous magnification or reduction, an automatic switch to a higher or lower magnification objective occurs when the at least one first optical element reaches a lower or upper stop of the zoom optics, limiting its movement. This requires that the objective turret be motorized. During the motorized objective change, the microscope body can be simultaneously adjusted upwards or downwards along the z-direction on the stand to readjust the focal plane, should it change initially during the switch, thus minimizing waiting time. The at least one first optical element can also be moved simultaneously.

[0018] Additionally, an observer can be notified of an upcoming lens change by an acoustic or visual signal, preferably a signal reflected in the eyepiece or displayed on the monitor. This can occur, for example, when the first optical element approaches one of its stops during zooming, provided the lens turret is not motorized. The signal can also indicate that a lens change is imminent in the case of a motorized lens turret, for instance, when the first optical element reaches a stop. The visual signal can also flash at different frequencies, with the frequency increasing as the lens change approaches. Furthermore, the signal can contain more detailed information, such as displaying the lens being changed on a control unit or in the eyepiece.

[0019] The output of an acoustic or optical signal is particularly useful when, in the case of a stereomicroscope or macroscope, vignetting of the image field increases during zooming. In the case of a motorized objective turret, an automatic objective change can also be performed to achieve minimal vignetting as vignetting increases; the signal then serves only to alert the observer.

[0020] According to the invention, for a given magnification, for example, the currently set magnification, the system determines, based on the objective data, the zoom optic data, and, if applicable, the eyepiece data, which of the objectives located on the objective turret will achieve maximum aperture and / or maximum depth of field at that magnification. This is signaled to an observer, for example, by display on a screen, on the screen of a control unit, or even in the eyepiece itself by reflection. The observer is then prompted to change the objective. Upon selecting the suggested objective, the preset magnification, usually the magnification set before the objective change, is restored.The difference lies in the fact that for the newly set combination of magnification and objective lens, either the aperture or the depth of field is maximized, depending on the observer's selection. Here, too, it is possible to automate this change with a motorized objective turret, provided this has been previously set and selected accordingly, for example, by the operator and observer.

[0021] In a preferred embodiment of the method, when an objective turret with at least three different objectives is used, the displacement of the at least one first optical element is initiated at the start of the objective change, i.e., when the objective turret is rotated, depending on the data of the objective being inserted. This saves time because all positions to be set are already known. The objective being inserted, and in particular its magnification, is preferably determined based on the direction of rotation of the objective turret. For example, the microscope can include a direction sensor to detect the direction of rotation when the objective is inserted. In a motorized objective changer, the data for the objectives are stored in a memory and read out to detect the objective being inserted, thus eliminating the need for a direction sensor.

[0022] The invention also relates to a microscope comprising a zoom optic for continuously adjusting the magnification, wherein the zoom optic itself comprises at least one first optical element and at least one second optical element, the at least one first optical element being motor-movable relative to the at least one second optical element along the optical axis. The microscope also comprises an objective turret with at least two objectives of different magnifications. For such a microscope—in particular also a stereomicroscope or a macroscope—the aforementioned problem is solved by integrating a control or control circuit that, when switching to an objective with a higher or lower magnification,At lower magnifications, at least one optical element is adjusted by a path length determined based on the objective and zoom optic data until the same magnification is set for an observer as before the switch, i.e., the same overall magnification. In particular, the previously described method for controlling the microscope can also be used and implemented in the control circuit. With such a microscope, continuous zooming can be achieved even across objective changes, thus avoiding the magnification jump typical of prior art. The same control method can also be used in a macroscope.

[0023] In cases where the objective turret is motorized and objective changes can be performed via control commands, it is advantageous for the control system to initiate an automatic objective change as soon as the first optical element reaches an upper or lower stop limiting its movement. This allows the entire magnification range offered by the microscope, together with the installed objectives, to be continuously and automatically traversed, utilizing all available objectives.

[0024] According to the invention, the microscope comprises means for generating and outputting an acoustic or optical signal. In the case of an optical signal, it preferably also includes means for projecting this signal into the eyepiece to indicate a lens change recommended by the control system depending on one or more system parameters, or—in the case of a motorized turret—an imminent lens change. This system parameter can, for example, be a zoom setting for the currently selected lens at which vignetting begins to increase in the peripheral areas of the image field. The system independently monitors whether further zoom adjustment will result in increased vignetting. Accordingly, a lens change is then suggested to the observer; however, in the case of a motorized turret, this change can also be performed automatically.The system parameter in this case would therefore be the minimum vignetting, i.e., the selection of the lens with the minimal vignetting at the set magnification. Other system parameters include the maximum aperture and the maximum depth of field. For the set magnification, the control system can determine which lenses in the lens turret are suitable for these settings. This information can also be displayed to the user on an additional screen, such as one found on a control unit. In the case of a motorized lens turret, the lens change can then be performed automatically or by pressing a corresponding button.

[0025] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations given, but also in other combinations or on their own, without leaving the scope of the present invention.

[0026] The invention will now be explained in more detail, for example with reference to the accompanying drawings, which also reveal essential features of the invention. These show... Fig. 1. The side view of a microscope in which a change of objective lens without a jump in magnification is possible, Fig. 2 the basic structure of a zoom lens, Fig. 3 Zoom ratios and magnification ranges for different lenses, Fig. 4 the screen that a viewer sees at a control panel before starting the procedure to avoid a magnification jump and Fig. 5 the excerpt from the subprogram for avoiding zoom jumps for operation, as it is displayed on the control panel.

[0027] In Fig. Figure 1 shows a microscope which includes a zoom optic for continuous adjustment of the magnification. The zoom optic is arranged in a microscope body 1. On the underside of the body is an objective turret 2 with at least two objectives 3, 4 of different magnifications. The microscope is shown here in cross-section. The motorized adjustment of the microscope body, and thus of the zoom optic as a whole, for focusing during zooming, is achieved by means of a motor drive 5 along a column 6, which is provided with a profile guide 7. The motor drive 5 interacts with this guide in such a way that minimal adjustments in the sub-micrometer range are possible.

[0028] The profile guide 7 is limited at the top and bottom. At the lower end of the column 6 is a stage 10, which here has an opening for transmitted light illumination and on which the object to be examined is fixed. The microscope body 1 contains the essential parts of the zoom optics, in particular the motors and lenses, i.e., the first optical elements necessary for the continuous adjustment of the magnification. The data for the zoom optics is also stored in a corresponding memory element in the microscope body 1. An eyepiece tube 11 is mounted on top of the microscope body 1; in the case of a stereomicroscope, this is a binocular tube.

[0029] The microscope body 1 is also linked to a control mechanism that, when switching to an objective 3, 4 with higher or lower magnification, adjusts at least one of the first optical elements by a distance determined based on the objective data and the zoom optics data, until the same magnification is set for the observer as before the switch. In this way, sudden changes in magnification can be avoided or are automatically corrected when an observer changes an objective.

[0030] If the lens turret 2 is motorized, an automatic lens change can be performed by means of the control system when, during continuous magnification or reduction, at least one of the first optical elements reaches an upper or lower limit. An automatic switch then occurs to a lens 3 or 4 with a higher or lower magnification, depending on the direction – greater or lesser – of the zoom movement.

[0031] In Fig. Figure 2 illustrates the structure of a zoom optic in a simplified manner for a stereomicroscope. The structure can be applied in the same way to simple microscopes with zoom optics, or to macroscopes. The zoom optic comprises two first optical elements 10 and 11 for each of the two beam paths—which are then combined, for example, in a common main objective—that are movable relative to two second optical elements 12 and 13. This movement is achieved by stepper motors 14 and 15, which move the lenses, arranged in mounts 16 and 17, along rods or drives 18 and 19. The motors are controlled by a controller 20, which also controls the movement of the microscope body.

[0032] In Fig. Figure 3 illustrates the automatic or manual switching. It shows the magnification ranges achievable with the zoom optics integrated into the microscope body 1 for three different objectives. For example, if the objective with the longest focal length and therefore the lowest magnification, designated "S 0.63x", is used and magnified via a control unit, at least one optical element 10, 11 will reach its upper limit during zooming with continuous focusing, corresponding to the right end of the black bar. The system then switches automatically or manually to the "S1.0x" objective, the one with the next higher magnification.At the upper limit, however, the magnification is also located at the right end of the bar of the associated lens; the magnification is higher and the image area smaller, which would lead to a jump in magnification without the control.

[0033] The control mechanism moves at least one optical element downwards from its upper limit, indicated by the curved arrow from right to left, until the original magnification with the original lens is restored for an observer. Only then does the zoom continue continuously, if desired by the viewer. This process is repeated when switching to the next lens, labeled "s1.5X".

[0034] Similarly, when zooming down (i.e., reducing the magnification), at least one of the first optical elements at the lower limit can also be moved slightly upwards when switching from a lens with higher magnification to one with lower magnification. The adjustment ranges are smaller in this area.

[0035] The microscope comprises means for generating and outputting an acoustic or optical signal, preferably with means for feeding the optical signal into an eyepiece such as the binocular in the eyepiece tube 11, to signal an objective change recommended by the control system or to be carried out shortly, depending on one or more system parameters. Thus, an observer is notified of an objective change by an acoustic or optical signal, preferably by a signal reflected into the eyepiece or displayed on a monitor, if this change is to be carried out automatically. This can be done depending on various system parameters.

[0036] One possible system parameter is, for example, the minimum vignetting of the image field when the microscope is designed as a stereomicroscope. Due to the beam path, shadowing of the image field occurs at certain positions. The timing and intensity of this shadowing depend on the specific objective used, but can be determined from the objective and zoom optic data. The corresponding signal is then output according to the zoom optic positions, depending on the zoom direction (magnification or reduction). With a manually operated objective turret 2, the observer should then change objective 3 or 4 to avoid vignetting. The operator can be shown which objective 3 or 4 to switch to in a corresponding control unit or on a monitor. In this case, the objective change is only recommended.However, if the lens turret 2 is motorized, it can also be performed automatically. The signal then serves only to inform the observer. Even with a motorized lens turret 2, the control can optionally be limited to merely recommending the lens change and not performing it without confirmation from the observer.

[0037] Other possible system parameters are the maximum aperture and the maximum depth of field. The control system determines which of the lenses in the objective turret offers the maximum aperture or depth of field at the currently set magnification or any other specified magnification. This combination of lens and magnification can then be displayed on the screen of a control unit, for example, as an optical signal, which may also include the display of text. The user can then decide by pressing a button whether to select the suggested combination and switch to the combination with maximum depth of field or maximum aperture for the currently set magnification, or whether to disregard this option.

[0038] In Fig. Figure 4 shows a menu as it appears, for example, on a control unit for a stereo microscope. In the Fig. In the main menu shown in section 4, you will find, among other things, an item called "Zoom Manager". This menu item contains the control described above, which serves to avoid sudden zoom jumps. When you select this menu item, the following will be displayed: Fig. The menu shown in section 5 is displayed. First, the control can be activated ("ON") or deactivated ("OFF"). With the control activated, the menu can be exited and other submenus, as shown in [section / description], can be accessed. Fig.As shown in Figure 4, further work can be carried out. The control system is then permanently activated and, when changing lenses, ensures that the previously selected magnification is restored by adjusting at least one of the first optical elements, thus preventing a sudden jump in magnification. In the other three modes ("minimal vignetting," "maximum aperture," and "maximum depth of field"), corresponding signals are output or calculations are performed, and the results are displayed. In the case of a motorized lens turret 2, the optimal lens 3 or 4 can also be switched immediately at the selected magnification by choosing the "maximum aperture" menu item, without requiring any additional confirmation from the observer. Advantageously, an indication of which lens 3 or 4 is being switched to is displayed. A similar procedure can be used in the "maximum depth of field" mode.

[0039] Overall, controlling the microscope in the manner described above makes it possible to avoid annoying jumps in magnification when changing objectives, especially in a stereomicroscope or a macroscope; manual adjustment of the magnification is also unnecessary. Reference symbol list 1 microscope body 2 lens turrets 3, 4 lens 5 shoots 6th pillar 7 Profile guidance 8 Table 9 Eyepiece tube 10, 11 first optical element 12, 13 second optical element 14, 15 stepper motor 16, 17 bracket 18, 19 Drive 20 Control

Claims

[1] Method for controlling a microscope with a zoom optic for continuously adjusting the magnification by the motorized displacement of at least one first optical element of the zoom optic along an optical axis relative to at least one second optical element of the zoom optic, and with an objective turret (2) with at least two objectives (3, 4) of different magnifications, wherein, when switching to an objective (3, 4) with a higher or lower magnification, the at least one first optical element is displaced by a path length determined on the basis of the objective data and the data of the zoom optic until the same magnification is set for an observer as before the switching, characterized by, that for a given magnification, the objective data determines which of the objectives (3, 4) will achieve a maximum aperture and / or a maximum depth of field and / or a minimum vignetting at this magnification, signals this to an observer and suggests an objective change, and sets the given magnification when the suggested objective (3, 4) is selected. [2] Method according to claim 1, characterized by , that during continuous enlargement or reduction an automatic switching to a lens (3, 4) with higher or lower magnification takes place when the at least one first optical element hits a lower stop or upper stop of the zoom optics to limit the displacement. [3] Method according to claim 1 or 2, characterized by, that an observer is advised or notified of a change of objective before switching to an objective (3, 4) with higher or lower magnification by an acoustic signal or an optical signal, preferably reflected into the eyepiece or displayed on a monitor. [4] Method according to claim 3, wherein the signal, in the case of a microscope designed as a stereomicroscope, signals a vignetting of the image field. [5] Method according to one of the preceding claims, wherein in the case of an objective turret (2) with more than two objectives (3, 4) at the beginning of the objective change by rotating the objective turret (2) depending on the data of the pivoting objective, the displacement of the at least one first optical element is also initiated. [6] Method according to claim 5, wherein the pivoting lens is determined based on the direction of rotation of the lens turret (2). [7] Microscope comprising a zoom optic for continuous adjustment of the magnification, which includes at least one first optical element and at least one second optical element, wherein the at least one first optical element is motor-movable relative to the at least one second optical element along the optical axis, and an objective turret (2) with at least two objectives (3, 4) of different magnifications, which has a control mechanism which, when switching to an objective (3, 4) with a higher or lower magnification,The microscope, at a lower magnification, shifts at least one first optical element by a path length determined on the basis of the objective data and the data of the zoom optics until the same magnification is set for an observer as before the switching; the microscope also includes means for generating and outputting an acoustic or optical signal to signal an objective change recommended or imminent by the control system depending on one or more system parameters. characterized by , that the system parameter is the maximum aperture, the maximum depth of field, or, in the case of a microscope designed as a stereomicroscope, a minimum vignetting depending on the magnification set. [8] Microscope according to claim 7, wherein the zoom optics are equipped with a lower stop (8) and an upper stop (9) to limit the displacement of the at least one first optical element, wherein the objective turret (2) is motorized and the control performs an automatic objective change when the at least one first optical element reaches one of the stops (8, 9). [9] Microscope according to one of claims 7 or 8, wherein the means for generating and outputting an optical signal are designed as means for reflecting the optical signal into an eyepiece. [10] Microscope according to one of the preceding claims 7 to 9, further comprising an objective turret with more than two objectives (3, 4) and means for detecting the objective pivoting in during an objective change, wherein the control is designed such that, based on the data of the pivoting objective, a displacement of the optical element is initiated at the beginning of the objective change. [11] Microscope according to claim 10, wherein the means for detecting the pivoting objective include a direction sensor for detecting the direction of rotation.

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