Vibration isolation device with coil spring and actuator

Abstract

The present invention generally relates to an active vibration isolator with a vertically active coil spring. The invention further relates to a method for actively damping vibrations of a supported load, such as a supported machine, plant or equipment. To this end, a vibration isolator is provided that includes an inner casing, the inner casing having a cavity for receiving and holding a vertically active coil spring, the coil spring being arranged in the cavity of the inner casing, and an outer casing surrounding the inner casing at least in a predetermined section. In this case, a vertically active actuator is arranged between the inner casing and the outer casing.

Description

[Technical field]

[0001] The present invention generally relates to an active vibration isolation device with a coil spring that is effective in the vertical direction. In particular, the present invention relates to a vibration isolation device that can be used in stationary vibration isolation systems for supporting machines, installations or equipment, especially in the field of the semiconductor industry, such as, for example, installations or equipment in the field of lithography, optical inspection equipment or wafer processing equipment. The present invention further relates to a method for actively damping vibrations of a supported load, for example a supported machine, installation or equipment.

[0002] Vibration isolation systems with mechanical springs, for example coil springs, are generally known. In such systems, the load to be isolated from the floor, for example equipment in the field of lithography, is supported on three or more vibration isolators that are effective at least in the vertical direction. With mechanical coil springs, passive vibration isolation is already possible in a very simple manner, especially in the case of relatively large and heavy loads. Vibration isolation can be achieved above the natural frequency of the spring-mass system.

[0003] The isolating effect of such vibration isolation systems, particularly when they are used to support sensitive machines, for example in the semiconductor industry, can be improved by forming them as active vibration isolation systems.

[0004] The mechanical spring system used is then designed to the weight of the load to be supported. This is necessary because mechanical springs no longer behave linearly at the limit range of loads, and therefore the damping properties deteriorate. Furthermore, the vibration isolator may be damaged.

[0005] It will be appreciated that for a given load range, the displacement of a coil spring behaves substantially linearly with respect to the applied force, so that the magnitude of the load that can be vibrationally isolated and supported varies with its weight.

[0006] In order to compensate for changes in the load to be isolated and supported or for uneven force distribution, it is known to provide such mechanical spring systems with height compensation. This can be achieved very simply, for example, via a height-adjustable spring bearing, in which case the vibration isolation system can be adjusted in the rest position. A mechanical vibration isolation device of this type is described in the applicant's EP-A-2 759 736.

[0007] However, in various cases, torques can occur during height adjustments in such mechanical spring systems that can result in horizontal forces. Such horizontal force components usually result in horizontal displacements of the vibration-isolated supported load or of the vibration isolator itself, which is undesirable. Horizontal displacements in active vibration isolation systems are particularly disadvantageous, since they cause oppositely located components of contactless actuators to be displaced from one another.

[0008] Thus, for example, in a magnetic actuator, the gap size between the magnets involved can change, which can have a detrimental effect on the output. The magnets can also be damaged. To prevent this, the actuator is designed as a separate component and is arranged spatially separated from the vibration isolator, for example in order to be able to reliably eliminate possible damage when adjusting a mechanical spring system.

[0009] Therefore, an alternative spring system based on a pneumatic spring is proposed in EP 3 181 944 A1.

[0010] However, such a type of pneumatic isolation system may have other drawbacks, for example, when the load to be isolated is a highly mobile mass and / or when high accelerations of the mobile mass are applied to the system. In such cases, high forces are required in the pneumatic spring, which requires a corresponding construction space. Furthermore, the structure and operation of such pneumatic springs are considered to be more complicated compared to coil springs.

[0011] Therefore, a vibration isolator that does not have these drawbacks is desirable.

[0012] It is desirable in this case for the vibration isolator to have as little construction space as possible in order to be able to use it flexibly.

[0013] In this case, it is desirable for the vibration isolator to also be usable for high loads, in particular loads having a weight of more than 500 kg, preferably more than 1000 kg.

[0014] The inventors are faced with such a problem.

[0015] This problem is solved in a surprisingly simple manner by a vibration isolator and a method for damping vibrations according to one of the independent claims. Preferred embodiments or refinements of the invention are set forth in the respective dependent claims.

[0016] The subject of the invention is therefore a vibration isolator, An inner casing having a hollow chamber for receiving and holding a coil spring, The coil spring is disposed in the hollow chamber of the inner casing and is effective in the vertical direction. an outer casing surrounding at least a predetermined section of the inner casing; and a vertically active actuator disposed between the inner casing and the outer casing at least in a predetermined section. A vibration isolation device comprising:

[0017] The vibration isolator may be part of a vibration isolation system that is installed in a stationary position and can be used to support equipment, for example in the semiconductor industry.

[0018] Such a vibration isolation system may, for example, comprise a vibration-isolated supported table or frame, on which the corresponding equipment is supported. "Horizontal" and "vertical" are to be understood within the scope of the present invention as the main directions of the vibration isolator in the assembled state. For a coil spring, the vertical direction thus corresponds to the orientation of the central axis of the coil spring in the operating state, i.e. the axial direction. In this direction the vibration isolator is effective.

[0019] To connect the vibration isolator to the floor, the outer casing can be made with suitable fastening means for forming a rigid connection with the floor, for example a screw connection can be provided for rigidly and releasably connecting the vibration isolator to a suitable holder, for example in the floor.

[0020] The outer casing can accommodate the inner casing at least in a certain area therein. According to a preferred embodiment of the invention, the outer casing surrounds the inner casing along its outer wall, so that the inner wall of the outer casing faces the outer wall of the inner casing.

[0021] The outer casing and the inner casing may be cylindrically shaped, which may be advantageous in terms of uniform force distribution and insulation, and preferably the outer casing, the inner casing and the coil spring are arranged concentrically with respect to one another.

[0022] In a preferred embodiment of the invention, the outer casing and the inner casing are furthermore rigidly connected to each other in the horizontal direction. To allow the movements required for vibration isolation, the inner casing is preferably vertically movable inside the outer casing. In other words, the inner casing with the coil springs can move axially or vertically relative to the outer casing, but is rigidly connected to the outer casing in the radial or horizontal direction.

[0023] The horizontally rigid connection of the inner casing may be achieved by at least one spring element, preferably at least one leaf spring, which may be connected in parallel to the actuator, which may be arranged in the working chamber of the vibration isolator and connects the inner casing to the outer casing.

[0024] Preferably, the vibration isolator comprises at least two leaf springs spaced apart in the axial direction, which allows particularly good resistance to tilting movements of the inner casing relative to the outer casing and allows a horizontally rigid connection to be achieved.

[0025] The leaf springs can in this case be part of a leaf spring package. For example, segmented leaf springs formed from ring segments are conceivable. In a particularly preferred embodiment, two leaf spring packages are provided which are arranged axially spaced apart from one another, for example in the region of the end faces of the inner and outer casings.

[0026] This allows the leaf springs to be arranged exchangeably, which allows the natural frequency of the vibration isolator to be easily adjusted by changing the spring package, and thus adapted to various load situations. In particular, natural frequencies of above 5 Hz can be achieved in order to achieve short adjustment times.

[0027] In a preferred embodiment of the invention, the coil spring is mechanically rigidly connected to the inner casing in the horizontal direction and is therefore insulated in the vertical direction. The inner casing may be formed with suitable means for receiving and holding the coil spring, for example with a spring seat in which the coil spring can be rigidly mounted in the horizontal and vertical directions.

[0028] According to the invention, a vertically effective actuator is provided, which can be arranged in the working chamber of the vibration isolator, which allows a particularly uniform introduction of forces into the vibration isolator with optimal space utilization.

[0029] In a particularly preferred embodiment of the invention, the actuator is configured as a magnet actuator and comprises at least one coil and a magnet forming a magnet coil pair. The coil and the magnet can be arranged between the inner casing and the outer casing, for which purpose a corresponding cavity or working chamber can be provided. The working chamber can comprise, for example, a recess on the inner wall of the outer casing and / or a recess on the outer wall of the inner casing.

[0030] Thus, by means of the actuator, in addition to the coil spring, additional vibration isolation in the vertical direction is possible. In this case, the actuator serves in particular for active vibration isolation. The vibration isolator according to the invention can therefore also be called an active vibration isolator.

[0031] In a preferred embodiment, at least one pair of magnet coils surrounds the coil spring at least in a predetermined section, in other words the coils and / or magnets are arranged around the coil spring at least in a predetermined section.

[0032] In a particularly preferred embodiment, at least one pair of magnet coils is in this case ring-shaped or based on a ring-shaped segment. In this way, the coil spring can be partially or preferably completely surrounded. This allows the actuator to introduce a particularly uniform force into the vibration isolator. In particular, this makes it possible to prevent the actuator from introducing a force that is not uniform on one side, which would lead to a tilting of the inner casing.

[0033] In a preferred embodiment, at least one coil of the actuator extends around the inner casing and is therefore arranged on the outer wall of the inner casing. The at least one coil can in this case, for example, be pressed or glued onto the inner casing. The associated magnet, in particular a permanent magnet, can in this case be assigned to the outer casing and can extend onto the inner wall. The associated magnet can also be glued.

[0034] Preferably, the magnet and the associated coil are arranged opposite each other, with a gap being present between the magnet and the coil.

[0035] Due to the horizontally rigid connection between the inner and outer casings, the gap can be made correspondingly particularly narrow, for example it can have a radial width of less than 5 mm, preferably less than 1 mm, particularly preferably less than 0.5 mm, which on the one hand allows the working chamber to be made correspondingly small, so that the entire vibration isolator can be kept compact, and on the other hand allows relatively high forces to be generated.

[0036] In another embodiment, a reverse arrangement may be provided, i.e. an arrangement of magnets on the outer wall of the inner casing and an arrangement of coils on the inner wall of the outer casing.

[0037] According to a preferred embodiment, the vibration isolator comprises a number of actuators, preferably magnetic actuators, arranged axially adjacent to one another. In one embodiment, the vibration isolator comprises at least two, particularly preferably three or more, actuators, in particular magnetic actuators, arranged adjacent to one another. This allows higher forces to be generated in a compact construction space.

[0038] Preferably, in this case, the current flows in the adjacent magnet coil pairs in opposite directions, so that the winding directions of the adjacent coils and the magnetization directions of the magnets preferably alternate between the adjacent magnet coil pairs.

[0039] In an odd number of magnet coil pairs, for example three, the central magnet coil pair may be dimensioned larger than the outer magnet coil pairs or actuators to allow for a uniform force introduction over the length. This configuration advantageously reduces the saturation of the magnetic field between the different magnet sets, which ultimately results in a higher magnetic inductance (B) in the coil gap. For this reason, the central magnet coil pair may have twice the number of coil turns compared to both outer magnet coil pairs.

[0040] The outer magnet coil pairs can therefore have the same number of coil windings, in which way it is particularly easy to generate two magnetic fields adjacent to one another in the axial direction, via which a vertical movement of the inner housing relative to the outer housing can be effected.

[0041] In this case, adjacent pairs of magnet coils may be spaced apart from each other in the axial direction by approximately 1 to 5 mm, and a magnetic shield may be provided between them.

[0042] In a preferred embodiment, the vibration isolator further comprises a preferably elongated insert which serves for absorbing loads. In this case, the insert can extend into the coil spring at least in a certain section. At its upper end, the insert can be rigidly connected to the inner casing and can have an upper receiver for receiving the coil spring, for example an upper spring seat. In another embodiment, the insert can be formed as part of the inner casing.

[0043] In this case, the insert can be at least partially formed with an upwardly open cavity in the region where it projects into the coil spring, which cavity can serve to accommodate a load receptacle. The load receptacle can be rigidly connected in the axial and radial directions in the lower region of the cavity to the bottom region of the insert. Thus, while the load receptacle is held at the bottom of the insert, in the upper region it can be freely arranged in the cavity, thus providing a radial or horizontal displaceability.

[0044] The load receiver can be particularly preferably designed as a bent rod or a bent pendulum and can be connected at its upper end to the load to be isolated. For this purpose, suitable receivers can be provided, so that forces acting horizontally on the load to be isolated can be absorbed via the load receiver.

[0045] In another aspect, the invention comprises a method for isolating a load to be supported, in which at least one vibration isolator according to the invention as described above is used.

[0046] In this case, the method involves placing a sensor on the load and / or on the floor to be isolated and then controlling at least one actuator of a vibration isolator, which actively counteracts the resulting vibrations, via a control loop. The sensor can be formed, for example, as a motion sensor or an acceleration sensor.

[0047] In yet another aspect, the invention comprises an apparatus, in particular a lithography apparatus or lithography equipment, optical inspection equipment, equipment or apparatus for processing wafers or substrates, comprising at least one vibration isolator as described above for vibration isolation. In a preferred embodiment, such an apparatus may comprise at least three such types of vibration isolators for three-point support.

[0048] It is also conceivable and possible to operate two of such types of vibration isolation devices together, in which case the two vibration isolation devices are arranged rotated by 90° relative to one another, thereby enabling active vibration isolation both in a first direction, e.g. the vertical direction, and in a second direction, e.g. the horizontal direction.

[0049] The vibration isolator according to the invention is distinguished by a small installation space and can therefore be used very flexibly.

[0050] Furthermore, the vibration isolator according to the invention can also be used for high loads, in particular for loads having a weight of more than 500 kg, for example more than 1000 kg or even more than 1500 kg.

[0051] Further details of the invention will become apparent from the description of the illustrated embodiments and the appended claims. [Brief description of the drawings]

[0052] [Figure 1] 1 is a cross-sectional view showing an embodiment of a vibration isolator according to the present invention; [Diagram 2] FIG. 2 is a perspective view of the vibration isolator of FIG. [Diagram 3] FIG. 2 is a schematic side view of a vibration isolation system. [Figure 4] FIG. 3 is a perspective cross-sectional view of the vibration isolator of FIG. 2. [Diagram 5] FIG. 2 is a cross-sectional view of a portion of a vibration isolator according to the present invention including a side wall. [Figure 6]FIG. 6 shows the magnetic field generated in the region of the side wall of FIG. 5 during operation.

[0053] Detailed Description of the Preferred Embodiments DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments are described in detail below, and for the sake of clarity, substantially identical parts in each embodiment are designated by the same reference numerals. However, in order to more clearly illustrate the present invention, the preferred embodiments illustrated in the drawings are not necessarily drawn to scale.

[0054] FIG. 1 illustrates in cross-section an embodiment of a vibration isolator 10 according to the present invention.

[0055] The illustrated vibration isolator 10 in this case is An inner casing 20 with a hollow chamber 21 for receiving and holding a coil spring 50, The coil spring is arranged in a hollow space 21 of the inner casing 20 and is effective in the vertical direction. an outer casing 30 surrounding the inner casing 20 at least in a predetermined section; and a vertically active actuator 40 disposed between the inner casing 20 and the outer casing 30. Includes.

[0056] The vibration isolator 10 may be part of a vibration isolation system 1 that is installed in a stationary position and can be used to support equipment, for example in the semiconductor industry.

[0057] Such a vibration isolation system 1 can, for example, comprise a vibrationally isolated and supported table 4 or frame, on which corresponding equipment is supported, for example a scanning electron microscope 5. The vibration isolation system 1 is only diagrammatically shown in a side view in Fig. 3. The table 4 and, as a load to be supported thereon, the equipment 5, can be isolated from the floor 2 by vibration isolators 10. In this embodiment, a total of four such vibration isolators 10 are provided.

[0058] For connecting the vibration isolator 10 to the floor, the outer casing 30 can be provided with suitable mounting means for forming a rigid connection with the floor or with the holding plate 3. For this purpose, for example, a screw connection 31 can be provided for rigidly and releasably connecting the vibration isolator to, for example, a suitable holding part.

[0059] The outer casing 30 is capable of accommodating the inner casing 20 at least in a certain area or section therein, and for this purpose is also formed with a hollow space, also referred to below as working chamber 32 .

[0060] In the embodiment shown, the outer casing 30 almost completely surrounds the inner casing 20, so that the inner wall 33 of the outer casing 30 and the outer wall 23 of the inner casing 20 face each other. It is not necessary that the outer casing 30 completely surrounds the inner casing 20 in the axial direction. The inner casing 20 could, for example, protrude, but this could lead to reduced stability, especially in the horizontal direction.

[0061] In the embodiment, the outer casing and the inner casing are formed cylindrically, which has been found to be advantageous and suitable for uniform absorption and damping of the load, allowing the inner casing 20 and the outer casing 30 and the coil spring 50 to be arranged concentrically with respect to the center line 51, which is highly advantageous for uniform weight distribution and uniform load distribution.

[0062] The outer casing 30 and the inner casing 20 are mechanically rigidly connected to one another in the horizontal direction.

[0063] To allow the movements required for vibration isolation, the inner casing 20 is held vertically movable inside the outer casing 30. In other words, the inner casing 20 with the coil springs 50 can move axially or vertically relative to the outer casing 30.

[0064] The connection of the horizontally rigid inner casing 20 is in this example provided by two leaf spring packages 34 as vertically acting spring elements which are connected in parallel to the actuators 40. The leaf spring packages 34 are arranged in the working chamber 32 of the vibration isolator 10 and connect the inner casing 20 to the outer casing 30.

[0065] In this embodiment, the vibration isolator 10 includes two leaf spring packages 34 that are axially spaced apart from each other and are arranged on each end face of the inner casing 20 and the outer casing 30, thus providing the greatest possible stability in the horizontal direction, thereby resisting tilting of the inner casing 20 relative to the outer casing 30, thereby providing a rigid connection in the horizontal direction.

[0066] The leaf spring package 34 includes a number of leaf springs. Instead of leaf springs, other spring elements are also conceivable, for example disc springs are possible.

[0067] The leaf spring packages 34 are arranged so that they can be easily replaced. For this purpose, a clamping ring 35 is provided on each end face, by means of which the leaf spring packages 34 can be firmly and removably connected to the outer casing 30 and in so doing can be held.

[0068] By changing the spring elements, the natural frequency of the vibration isolator 10 can be easily adjusted and thus adapted to different load situations. In particular, natural frequencies above 5 Hz can be achieved in order to achieve short adjustment times.

[0069] The coil spring 50 is mechanically rigidly connected to the inner casing 20 in the horizontal direction and is therefore insulating in the vertical direction. The inner casing 20 is formed with corresponding means for receiving and holding the coil spring 50, in this example with a lower spring retainer 24 in which the coil spring 50 can be rigidly mounted in the horizontal and vertical directions. The spring retainer 24 can be moved axially by means of adjustment means 52 to perform a height adaptation.

[0070] According to the invention, vertically active actuators are provided, which are arranged in the working chamber of the vibration isolator and are designated as a whole by the reference numbers 40, 40a. The actuators 40, 40a are configured as linear motors with a straight path of motion and allow a particularly uniform introduction of forces into the vibration isolator 10.

[0071] In the exemplary embodiment, the actuator 40, 40a is formed as a magnetic actuator and comprises a coil 41, 41a and a magnet 42, 42a, which respectively form a magnetic coil pair. The coil 41 and the magnet 42 are arranged in the working chamber 32 between the inner casing 20 and the outer casing 30 and form a magnetic coil pair. In the working chamber 32, a recess on the inner wall of the outer casing 30 and / or a recess on the outer wall of the inner casing 20 are formed to accommodate the magnet 42 or the coil 41. In the exemplary embodiment, the coil is press-fitted or glued to the outer wall of the inner casing 20. In this case, the inner casing 20 is advantageously manufactured from an iron-containing material, preferably steel. The magnet 42 is inserted and glued into a similar, precisely fitting recess on the inner wall of the outer casing 30.

[0072] Thus, by means of the actuators 40, 40a, additional vibration isolation in the vertical direction, parallel to the coil spring 50, is possible. The actuators 40, 40a in this case form the active elements of the vibration isolator 10.

[0073] In the illustrated embodiment, a total of three magnet coil pairs are provided, which completely surround the coil spring 50 and extend axially approximately along the length of the coil spring 50, which provides a high degree of stability and at the same time a good arrangement for a compact construction of the vibration isolator 10.

[0074] In the illustrated embodiment, the magnet coil pair is formed in the shape of a ring, which allows the coil spring 50 to be completely surrounded. This allows a particularly uniform introduction of forces into the vibration isolator 10 by the actuators 40, 40a. In particular, this prevents the actuators 40, 40a from introducing forces that are not uniform on one side, which would lead to tilting of the inner casing 20.

[0075] In the illustrated embodiment, the windings of the coil 41 of the actuator 40, 40a surround the outer wall of the inner casing 20. The associated magnet 42, in the embodiment a permanent magnet, is assigned in this case to the outer casing 30 and is arranged at a small distance from the coil 41 on the inner wall. The magnet 42 and the associated coil 41 are therefore arranged opposite each other, and a gap exists between the magnet 42 and the coil 41.

[0076] Due to the horizontally rigid connection between the inner casing 20 and the outer casing 30, this gap is accordingly particularly narrow. In the present embodiment, the gap has a width of less than 5 mm, preferably less than 1 mm, particularly preferably less than 0.5 mm. On the one hand, this allows the working chamber 32 to be made accordingly small, so that the entire vibration isolator 10 can be kept compact. On the other hand, relatively high forces can be generated. A reverse arrangement of the magnets 42 and the coils 41 is also possible and conceivable.

[0077] In the illustrated embodiment, the vibration isolator 10 comprises three actuators 40, 40a arranged axially adjacent to one another and connected in parallel, in this example magnet actuators or magnet coil pairs. In general, embodiments comprising more than one actuator 40, 40a, for example two or four or five or more actuators 40, 40a arranged adjacent to one another, in particular magnet actuators, are also possible and contemplated.

[0078] This allows for higher forces to be generated in a compact working chamber 32. In this case, adjacent magnet coil pairs are passed through with currents in opposite directions, so that in an arrangement with three magnet coil pairs, two magnetic fields can be generated that are axially separated.

[0079] In order to allow for a uniform force introduction over the length in an odd number of magnet coil pairs, for example three or five magnet coil pairs, the central magnet coil pair, designated in the illustrated embodiment by reference number 40a, is dimensioned larger than the outer magnet coil pairs or actuators 40 in order to allow for the same or higher force introduction with the same current. For this purpose, the central magnet coil pair 40a, which includes coil 41a and magnet 42a, has twice the number of coil turns of coil 41a in comparison with the two outer magnet coil pairs. It is also possible to select a different, in particular a larger introduction cross section, or to combine a modified introduction cross section with a modified number of turns. The outer magnet coil pairs are in this case similarly shaped with respect to the output parameters.

[0080] In this case, the magnet coil pairs adjacent in the axial direction have a predetermined distance from each other, which is 1 to 5 mm in this embodiment. In order to reduce the distance, in this embodiment, a shielding intermediate member 43 is provided between the adjacent magnet coil pairs.

[0081] The vibration isolator 10 further comprises, in the embodiment shown, an elongated insert 25 which serves to absorb loads and which, on the one hand, projects for the most part into the coil spring 50. At its upper end, the insert 25 is rigidly connected to the inner casing 20.

[0082] The insert 25 includes an upper receiver for receiving a coil spring, in this example the upper spring retainer 24. In another embodiment, the insert 25 together with the upper spring retainer 24 may be formed as part of the inner casing 20.

[0083] In this case, the insert 25, in the region where it projects into the coil spring 50, is formed with an upwardly open cavity, which serves to receive a load receptacle 53. The load receptacle 53 is arranged coaxially with the insert 25 and the coil spring 50 and is firmly connected in the axial and radial directions to the bottom area of ​​the insert 25 in the lower region of the cavity. The load receptacle 53 is thus held on the bottom of the insert. In the upper region or upper end face of the insert 25, the load receptacle 53 is arranged horizontally freely in the cavity, so that it is movable in the radial direction.

[0084] The load receptacle 53 is in the present embodiment formed as a bent rod. The upper end of the load receptacle can be coupled to the load to be isolated. For this purpose, in the present embodiment, a further receptacle 54 is provided. The load to be isolated is not shown in this figure. Forces acting horizontally on the load to be isolated can thus be absorbed via the load receptacle 53.

[0085] FIG. 2 shows the vibration isolator 10 in a perspective view. The lateral recesses 36 allow the vibration isolator 10 to be adjusted in height when assembled. The vibration isolator 10 has an overall construction height of approximately 150 mm and a diameter of approximately 130 mm and is therefore very compact. The extension of the coil spring in the axial direction is approximately 90 mm. Approximately over this distance, a total of three magnet coil pairs are also distributed, the central magnet coil pair having an axial extension approximately twice that of each outer magnet coil pair. With this dimension, a travel of approximately 1.5 mm or more is possible.

[0086] FIG. 4 illustrates the vibration isolator 10 of FIG. 2 in a perspective cross-sectional view.

[0087] FIG. 5 shows a portion of the side walls of the inner casing 20 and outer casing 30 of the vibration isolator 10 in cross section.

[0088] 6 shows the magnetic field which occurs during operation in this region of the side wall of the vibration isolator 10. Two magnetic fields 44 which are spaced apart from each other in the axial direction can be clearly seen. In the cross section, the extension of the magnetic field lines is indicated diagrammatically with the reference number 45.

[0089] The invention therefore provides a method for isolating a load to be supported, such as a scanning electron microscope 5, lithography equipment or lithography installations, optical inspection equipment, equipment or devices for processing wafers or substrates, or other devices or installations which place particularly high demands on vibration isolation.

[0090] The invention further includes equipment, such as lithography equipment or facilities, optical inspection equipment, equipment or devices for processing wafers or substrates, in which at least one vibration isolator 10 as described above is used.

Claims

1. 1. A vibration isolator comprising: an inner casing having a hollow chamber for receiving and holding a coil spring, an inner casing, the coil spring being disposed in the hollow chamber of the inner casing and being effective in a vertical direction; an outer casing surrounding the inner casing at least in a predetermined section; a vertically active actuator disposed between the inner casing and the outer casing; 1. A vibration isolation device comprising:

2. 2. The vibration isolator according to claim 1, wherein at least one spring element, preferably at least one leaf spring, is provided between the outer casing and the inner casing, the at least one leaf spring enabling axial movement of the inner casing relative to the outer casing.

3. 2. The vibration isolator according to claim 1, wherein at least two leaf springs are provided, which are arranged axially spaced apart from one another, and which are preferably formed as a leaf spring package.

4. 2. The vibration isolator of claim 1, wherein the actuator is configured as a magnetic actuator and includes at least one coil and a magnet forming a magnet coil pair.

5. 2. A vibration isolator according to claim 1, wherein the working chamber is provided with a recess for accommodating the coil and / or magnet of the magnetic actuator.

6. The vibration isolator of claim 1 , wherein at least one of the magnet coil pairs surrounds at least a predetermined portion of the coil spring.

7. 2. The vibration isolator of claim 1, wherein at least one of the magnet coil pairs is ring-shaped and completely surrounds at least a predetermined portion of the coil spring.

8. 2. The vibration isolation device according to claim 1, wherein a plurality of actuators, in particular magnet coil pairs, are provided, arranged adjacent to one another in the axial direction, preferably two, particularly preferably three or more magnet coil pairs, and the winding directions of the coils and the magnetization directions of the magnets of adjacent magnet coil pairs preferably alternate between adjacent magnet coil pairs.

9. 9. The vibration isolator according to claim 8, wherein the distance between two adjacent pairs of magnetic coils is 1 to 5 mm.

10. 2. The vibration isolator according to claim 1, wherein the coils of at least one magnet coil pair are arranged on the outer wall of the inner casing and / or the associated magnets are arranged on the inner wall of the outer casing.

11. 2. A vibration isolator according to claim 1, wherein a gap is provided between the magnet and the coil of the magnet coil pair, the gap having a width of less than 5 mm, preferably less than 1 mm, particularly preferably less than 0.5 mm.

12. 2. A vibration isolator according to claim 1, further comprising an insert which projects into the coil spring at least in a predetermined section, said insert preferably comprising an upwardly open hollow chamber.

13. The vibration isolator of claim 12 , wherein the insert is coupled to a load receiver that is rigidly coupled to the insert in both axial and radial directions.

14. 14. The vibration isolator of claim 13, wherein the load receiving portion extends at least a predetermined distance into the hollow chamber of the insert and / or the load receiving portion extends at least a predetermined distance into the coil spring.

15. 14. A vibration isolator according to claim 13, wherein the load receiver may be connected at its lower end to a bottom surface of the insert and / or at its upper end to the load or load receiver to be isolated.

16. 14. The vibration isolator of claim 13, wherein the load receiver is formed as a bending rod or a bending pendulum.

17. 2. The vibration isolator of claim 1, wherein the coil spring is mechanically rigidly coupled to the inner casing in a horizontal direction.

18. 18. A method for isolating a load to be supported, comprising the use of a vibration isolator according to any one of claims 1 to 17.

19. 18. An apparatus, in particular a lithography apparatus or lithography installation, an optical inspection apparatus, an installation or device for processing wafers or substrates, comprising at least one vibration isolator according to any one of claims 1 to 17.

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