MICROSCOPE WITH FRICTION DRIVES

The invention relates to a microscope (10, 50) having a specimen stage (12) movable in an X direction and/or a Y direction and having an objective turret (16), the microscope (10, 50) encompassing a first drive unit (14a) with which the specimen stage (12) is movable in the X direction, a second drive unit (14b) with which the specimen stage (12) is movable in the Y direction, and/or a third drive unit (14c) with which the objective turret (16) is rotatable. The connections between the drive units (14a, 14b, 14c) and the specimen stage or the objective turret (16) are respectively embodied as a frictional connection.

FIELD OF THE INVENTION

The invention relates to a microscope that comprises a specimen stage movable in an X direction and a Y direction, and an objective turret. The microscope furthermore has a first drive unit with the aid of which the specimen stage is movable in the X direction, and a second drive unit with the aid of which the specimen stage is movable in the Y direction. Also provided is a third drive unit with the aid of which the objective turret is rotatable.

BACKGROUND OF THE INVENTION

In known microscopes, force and torque are transferred from the drive units to the respective elements to be displaced, i.e. for example the specimen stage or the objective turret, via a positively engaging connection. Provided for this purpose, in particular, are gears, toothed racks, spindles, or toothed belts, by way of which the drive unit is connected to the element that is to be moved.

Positively engaging force transfer systems of this kind are disadvantageous firstly in that they require very high precision in order to run quietly. This requires very small tolerances in the context of production and assembly, making the microscopes very expensive to manufacture.

In addition, microscopes having a positively engaging force transfer system always exhibit hysteresis behavior upon a change in the direction of motion, making it more difficult to return precisely to desired positions.

The positively engaging drives are furthermore relatively loud and exhibit poor smoothness. Positively engaging drives of this kind also must be regularly lubricated, resulting in a recurring maintenance outlay.

SUMMARY OF THE INVENTION

The object of the invention is to describe a microscope that can be manufactured inexpensively and provides smooth, low-noise operation along with precise positioning of the movable elements.

This object is achieved with a microscope having the features disclosed herein. Advantageous refinements of the invention are described in the present specification.

According to the present invention, the microscope comprises a first drive unit with the aid of which the specimen stage is movable in the X direction. A frictional connection for transferring a torque and/or a force is embodied between the first drive unit and the specimen stage. Additionally or alternatively, the microscope can encompass a second drive unit with the aid of which the specimen stage is movable in the Y direction. The connection between this second drive unit and the specimen stage is likewise embodied as a frictional connection for transferring a torque and/or a force. Additionally or alternatively, a third drive unit, with the aid of which the objective turret is rotatable, can also be provided. The connection between the third drive unit and the objective turret is also embodied as a frictional connection for transferring a torque and/or a force from the third drive unit to the objective turret.

A “frictional connection” is understood to mean in particular that the torque and/or a force is transferred in exclusively frictionally engaging fashion, i.e. that the torque transfer and/or force transfer occurs exclusively by way of the friction existing between the respective drive unit and the specimen stage or objective turret. Frictionally engaging connections are often also referred to as “nonpositive” connections.

A “frictional connection” is understood in particular to mean that the torque transfer and/or force transfer occurs exclusively in frictionally engaging fashion, and no positive engagement exists between the drive unit and the respective moved element. In particular, the connection between the respective drive unit and the specimen stage or objective turret is embodied in non-toothed fashion.

Frictionally engaging connections of this kind offer a number of advantages as compared with the positively engaging connections ordinarily used in microscopes.

On the one hand, frictionally engaging connections offer substantially smoother operation than positively engaging connections by the fact that vibrations of the system are avoided, with the result that operating convenience for the microscope is enhanced. On the other hand, frictionally engaging connections are considerably quieter as compared with positively engaging connections, which further enhances the operating convenience of the microscope.

A further problem that exists with positively engaging connections, in particular with gears or toothed racks, is that upon a reversal of the motion direction, the teeth of the driven coupling element firstly must be moved from the one side of that region of the tooth set into which they are engaging to the other side of the tooth set, before they can actually move the element into which they are engaging. This produces a hysteresis behavior that is disadvantageous during use. Very stringent requirements in terms of tolerance must be applied in order to avoid this, necessitating very precise and therefore expensive manufacturing. This hysteresis behavior does not exist with frictionally engaging connections, however, resulting in simple and quick manufacture and assembly.

The use of frictionally engaging connections within the microscope thus makes possible simple and inexpensive manufacture and assembly, but still smooth, quiet, and precise operation.

In a particularly preferred embodiment of the invention, a flexible frictional drive is embodied respectively between the first drive unit and the specimen stage, between the second drive unit and the specimen stage, and/or between the third drive unit and the objective turret. A “flexible frictional drive” is understood to mean that the connection between the drive unit and the specimen stage or objective turret is embodied elastically, so that tolerances are automatically compensated for.

In a particularly preferred embodiment of the invention, the first, the second, and/or the third drive unit respectively comprises a first coupling element, and the specimen stage and/or the objective turret respectively comprises a second coupling element, the first coupling element being respectively coupled in frictionally engaging fashion to the respective second coupling element. The above-described frictionally engaging transfer of power and torque is thereby achieved in simple fashion.

In particular, at least one elastic element is respectively arranged between the two coupling elements, that elastic element being preloaded between the two respective coupling elements. The result is on the one hand that the frictional force which exists is increased, and on the other hand that tolerances are compensated for. Particularly simple manufacture is furthermore achieved. Preloading is achieved in particular by the fact that the spacing between the two coupling elements is smaller than the thickness of the elastic element.

The elastic element is embodied, in particular, from rubber.

In a particularly preferred embodiment of the invention, the elastic element is embodied from ethylene propylene diene rubber (EPDM). EPDM has the advantage that on the one hand it possesses a high coefficient of friction so that a large frictional force is generated, and on the other hand that the aging which occurs is not as great as with “normal” rubber, so that the elastic element does not need to be regularly replaced.

The elastic element is, in particular, fastened in nonrotating and stationary fashion on the respective second coupling element, i.e. its position relative to the coupling element on which it is fastened does not change during operation.

It is particularly advantageous if the coupling element on which the respective elastic element is fastened comprises a respective groove in which the elastic element is at least partly arranged. This groove, in particular, prevents slippage of the elastic element. In addition, the elastic element is itself arranged inside that groove, in particular, in preloaded fashion, so that rotation of the elastic element within the groove is also avoided.

In an alternative embodiment of the invention, at least two elastic elements are arranged between the two coupling elements respectively coupled to one another, the elastic elements being preloaded between those two coupling elements, and one of the two elastic elements being fastened in nonrotatable and stationary fashion on the first coupling element, and the other elastic element on the pertinent second coupling element.

Thanks to the use of two elastic elements between the two respective coupling elements, a greater frictional force and thus even more reliable transfer of force and torque are achieved.

The two elastic elements are arranged in particular with a mutual offset, so that they do not contact one another. This prevents the transfer of force and torque from occurring between the two elastic elements themselves, which might result in unstable transfer.

In a preferred embodiment of the invention, the first coupling element is embodied as a wheel or shaft. In this case the elastic element extends, in particular, around the entire circumference of the wheel or shaft.

The second coupling element, on which the moved part, i.e. the specimen stage or objective turret, is arranged, is embodied in particular as a wheel or rod.

It is furthermore advantageous if the first, the second, and/or the third drive unit respectively encompass an electric motor on whose respective drive shaft the first coupling element is mounted. Precise control of the motion of the specimen stage and of the objective turret is thereby achieved.

In a particularly preferred embodiment of the invention, the microscope comprises a rotary disk in which at least one fluorescence cube and/or at least one other optical element are arranged. The microscope comprises a fourth drive unit by way of which the rotary disk is rotatable. A frictional connection, for transferring from the fourth drive unit to the rotary disk a torque and/or a force for rotating the rotary disk, is embodied between the fourth drive unit and the rotary disk.

This frictional connection can be refined in particular with the same features that have been described previously for the frictional connection between the first drive unit and the specimen stage, the second drive unit and the specimen stage, and/or the third drive unit and the objective turret.

Displacement of the rotary disk by way of a smooth-running, quiet coupling of simple configuration can also thereby be achieved.

Further features and advantages of the invention are evident from the description below, which explains the invention in further detail on the basis of exemplifying embodiment in conjunction with the appended Figures.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a highly simplified schematic depiction of an upright microscope10.FIG. 2is a perspective schematic depiction of microscope10according toFIG. 1. Only the relevant functional parts of microscope10are respectively shown.

Microscope10comprises a specimen stage12on which the specimens to be microscopically examined are mounted. Specimen stage12is movable in an X direction, indicated by double arrow P1, with the aid of a drive unit14. Embodied for this purpose between drive unit14and specimen stage12is a frictionally engaging connection that will be described later in further detail in conjunction withFIG. 3.

Microscope10furthermore comprises an objective turret16that comprises a plurality of objectives, one of which is labeled by way of example with the reference character18. A different objective18is pivoted into beam path20of microscope10depending on the rotational position of objective turret16.

Microscope10furthermore has a rotary disk22on which fluorescence cubes and/or other optical objects can be fastened. In the example shown inFIGS. 1 and 2, only one fluorescence cube24is received in rotary disk22.

Rotary disk22is rotatable via a drive unit26; here as well, the coupling between rotary disk22and drive unit26is embodied in frictionally engaging fashion, as will be described further in conjunction withFIG. 4.

Microscope10furthermore has an illumination unit28for illuminating the specimen to be microscopically examined.

FIG. 3is a partly sectioned depiction of specimen stage12and of drive unit14. Drive unit14comprises a first coupling element30that is coupled to a second coupling element34of specimen stage12. First coupling element30is embodied in particular in the form of a shaft rotatable via drive unit14, and second coupling element34is embodied in particular as a rod.

First coupling element30comprises a circumferential groove32in which an elastic element36in the form of an elastic ring is received. The spacing between first coupling element30and second coupling element34is selected to be such that elastic element36becomes elastically deformed and is thus preloaded between the two coupling elements30and34. Upon rotation of first coupling element30, a corresponding force is transferred to second coupling element34by way of the friction existing between elastic element36and second coupling element34, so that the latter is moved in the desired direction.

A frictionally engaging force transfer between drive unit14and specimen stage12is thereby achieved in simple fashion.

FIG. 4ais a sectioned depiction of a portion of rotary disk22and of drive unit26. Rotary disk22comprises a circumferential groove38in which an elastic element40, likewise embodied as a ring, is arranged. The spacing between rotary disk22and drive unit26is once again selected in such a way that elastic element40becomes elastically deformed and is thus preloaded. A frictionally engaging force transfer between drive unit26and rotary disk22is thereby once again achieved in particularly simple fashion. Upon rotation of wheel42of drive unit26, a force is transferred from drive unit26to rotary disk22by way of the frictional force existing between wheel42and elastic element40, so that rotary disk22is rotated in the desired direction.

Both elastic element36and elastic element40are produced in particular from EPDM, which has the advantage on the one hand that a high coefficient of friction exists and thus a large frictional force is transferred, and on the other hand that the elastic element is subject to very little or no aging.

FIG. 4bis a sectioned depiction of a portion of rotary disk22and of drive unit26in accordance with an alternative embodiment. In this embodiment, two elastic elements40are arranged between rotary disk22and drive unit26.

FIG. 5is a schematic and likewise highly simplified depiction of an inverted microscope50. Elements having the same construction or the same function have the same reference characters.

In this inverted microscope, objective turret16is arranged below specimen stage12, so that the object that is to be microscopically examined and is arranged on specimen stage12can be viewed from below.

With this inverted microscope50as well, the coupling between drive unit14and specimen stage12, and the coupling between rotary disk22and drive unit26, are embodied as a frictionally engaging connection and, in particular, are embodied analogously to the exemplifying embodiment ofFIGS. 3 and 4.

In an alternative embodiment of the invention a further drive unit can also be provided, by way of which specimen stage12can be moved in a Y direction arranged orthogonally to the X direction. The connection between this further drive unit and specimen stage12is, in particular, also embodied in frictionally engaging fashion.

In a further alternative embodiment, a further drive unit by way of which the objective turret can be rotated can also be additionally or alternatively provided. The connection between the objective turret and this further drive unit is, in particular, also embodied as a frictionally engaging connection.

Further drive units for moving further movable elements within the microscope, which units in particular can likewise be coupled to the respective element via a frictionally engaging connection, can furthermore also be provided.

The use of frictionally engaging connections has the advantage, as compared with positively engaging connections such as gears, toothed racks, spindles, or toothed belts, that manufacturing costs are substantially lower, since positively engaging connections of this kind must be manufactured and assembled with high precision for smooth operation of the corresponding movable elements. With the frictionally engaging connections, tolerances are automatically compensated for by the elasticity of elastic elements36,40, so that very smooth and precise operation is achieved even with larger tolerances.

With conventional positively engaging drives a reversing backlash furthermore exists, resulting in a hysteresis upon reversal of the rotation direction or motion direction. Transfer via a frictionally engaging connection has the advantage that it is hysteresis-free, so that operating convenience is considerably enhanced.

The frictionally engaging connections are furthermore substantially quieter as compared with positively engaging connections. The positively engaging connections moreover require regular maintenance, in particular because the components used therein must be regularly lubricated. This is not the case with the frictionally engaging connections via elastic elements36,40, thus reducing maintenance outlay.

PARTS LIST