CLOSURE OR LOCK DEVICE FOR A VACUUM CHAMBER

Closure device or lock device for a vacuum chamber comprising          a counter plate, which can be arranged on a vacuum chamber and surrounds an opening of the vacuum chamber,     a frame, which is supported in such a way that the frame can be moved in relation to the counter plate and on which a closure cover is movably arranged, wherein the closure cover closes the opening in sealing manner in a closed position against the counter plate,     at least one magnet device for producing a closing force acting between the counter plate and the closure cover, which is in engagement with the counter plate and with the closure cover.

TECHNICAL FIELD

The present invention relates to a closure or lock device for a vacuum chamber with a counter plate which can be arranged on a vacuum chamber and surrounds an opening of the vacuum chamber and a closure cover, which closes the opening in a sealing manner in a closed position against the counter plate. In addition, the invention relates to a method for sealing an opening of a vacuum chamber by means of such a closure or lock device.

BACKGROUND

Closure and lock devices for vacuum chambers are adequately known from the most recent background art. In this respect, for example, WO 2005/121621 A 1 describes a lock device according to this class for a lock opening arranged in a wall between a first and a second recipient as well as a shut-off device arranged in the interior space of the first recipient and a counter plate assigned to the shut-off device. The flange-like counter plate surrounding the opening is provided with a circumferential seal, against which the shut-off device is pressed in a sealing manner.

To comply with a required tightness, in particular, in order to comply with high-vacuum conditions inside the vacuum chamber, it is desirable that the shut-off device presses in the circumferential direction as evenly as possible in the areas lying around the opening in a distributed manner. Applying an even and homogeneous pressing force across the entire seal is particularly difficult in the case of seals with a seal diameter of a few millimetres at a dimension of a shut-off element or a closure cover in the range of several decimetres or meters from a constructional and manufacturing-technology point of view.

The implementation of a lift of approximately 0.5 to 2 mm over the surface of the closure cover compressing the sealing ring at a range of 0.5 to 5 m2, for example, or beyond this, has been shown to be extremely expensive on a constructional and technical manufacturing level. In addition, the direct contact of counter plate and the closure cover, which are typically made of metal, must absolutely be avoided due to reasons regarding required clean-room conditions and for reasons regarding a required particle-free environment of the vacuum chamber associated therewith.

In addition, any possible shear movements between the seal and a metal component ending up resting on it must absolutely be avoided or kept to a minimum when sealing the closure or lock device, typically between the seal and the closure cover, also for reasons of complying with the required clean-room conditions and being free of particle contamination.

In addition, the fact that the seal, which is typically made of an elastomer material, for example, made of rubber, can be subject to an ageing process and that its elastic properties can change as the closure or lock device continues to be used. Furthermore, it is conceivable that the vacuum chamber is operated with different vacuum or pressure levels. Provided that the closure or lock device seals the interior space of the vacuum chamber against the atmosphere or another ambient pressure, for example, against a deviating pressure of an adjacent vacuum chamber, the contact pressure on the seal can vary depending on the respective predominate pressure in the vacuum chamber and can result in relative movements between the seal and the metal parts of the closure or lock device.

In this regard, the object of the present invention is to provide an improved closure or lock device for a vacuum chamber, by means of which a particularly even and as exclusively perpendicular as possible pressing force can be exerted on the seal when closing the vacuum chamber. In particular, it is an objective to avoid any shear movements or friction on the seal, which is typically rubber-elastic, between the counter plate and the closure cover or to reduce the shear movements or friction to an absolutely required minimum. With the device, a particularly low level of particle contamination and high level of purity in the area of the vacuum chamber should be able to be achieved. Furthermore, the closure or lock device should be characterized by a comparatively low weight and by easy and good manageability of its individual components with regard to manufacturing, assembly and long-term operation.

INVENTION AND ADVANTAGEOUS EMBODIMENTS

This object is solved by means of a closure or lock device according to independent Patent claim1. Favourable embodiments are the object of the dependent patent claims respectively.

In this respect, a closure or lock device for a vacuum chamber is provided. The closure or lock device has a counter plate, which encloses an opening of the vacuum chamber and which can be arranged on a vacuum chamber or has been arranged on it, or if applicable, has been integrated into the vacuum chamber or connected to a chamber wall. The counter plate is typically formed to be flange-like. It can protrude from the wall of the vacuum chamber toward the outside and has or forms a contact surface extending through the opening of the vacuum chamber approximately perpendicular to the direction of insertion.

The closure or lock device furthermore has a frame that is mounted in a moveable manner against the counter plate. In turn, a closure cover is arranged in a moveable manner. The closure cover can be brought to the counter plate into a closed position, in which the closure cover closes the opening of the counter plate in a sealing manner. It is particularly the frame, which is movably mounted to the counter plate between an open position and a contact position. In the open position, the frame and the counter plate arranged on it releases the opening of the vacuum chamber so that substrates to be treated in the vacuum chamber can be introduced into the vacuum chamber and be removed from it.

In a contact position, the frame is in mechanical contact with the counter plate. The closure cover, which is moveably mounted on the frame, can, in that contact position, abuts the counter plate in a relatively loose manner, typically abutting a seal enclosing the opening of the counter plate, however without exerting notable forces on the seal. It is also conceivable that the closure cover in the contact position of the frame on the counter plate is contact-free with respect to the counter plate or with respect to the seal typically arranged on the counter plate.

Sealing the opening and thus the vacuum chamber is achieved by moving the closure cover relative to the frame from the contact position of the frame, which is already in the contact position with the counter plate.

Furthermore, the closure or lock device has at least one adjustable and/or controllable magnet device or controllable magnet device in operable connection with the counter plate and the closure cover. This is configured to generate a closing force (C) acting between the counter plate and the closure cover. By means of the adjustable magnet device, the level and the direction of the closing force acting between the counter plate and the closure cover can be varied. Depending on the specific embodiment of the magnet device, both an attractive as well as repulsive force can be exerted onto the closure cover in order to optionally open or close the opening of the vacuum chamber by means of the closure cover depending on the predominate pressure level in the vacuum chamber and the vacuum chamber environment.

Thereby, the closure cover can be subject to a comparably low level of lift or a relatively short or small movement with relation to the frame. Such small or short movements can be made separately, and therefore can be especially well controlled or managed by means of the magnet device. In particular, by means of this, a defined and especially even deformation of the elastic seal between the closure cover and the counter plate can be achieved.

In further embodiment, the closure cover has a flat top surface. Furthermore, the closure cover can be slid in a direction parallel to a surface normal (N) of the top surface on the frame. Typically, the closure cover is moveably mounted to the frame between a rest position (U) and the closed position (S). It is typically translationally or linearly arranged on the frame in a moveable manner. By means of the closure cover being moveably mounted to the frame considerably perpendicular to the top surface and also perpendicular to a level of the frame, the closure cover can exert a homogeneous pressing force across the extent of the seal and therefore, also a homogeneous compression on the seal under the influence of the magnet device.

In particular, it is provided that the closure cover is moved by the magnet device only in the direction of the surface normal with respective to the frame in the case of a frame in the contact position and starting from a rest position on the frame. Any shear forces or relative movements rubbing along the seal between the closure cover and the seal can be considerably avoided in this way. When closing the closure or lock device, meaning when transferring the closure cover out of a rest position on the frame into the closed position compressing the seal, the seal solely or primarily only experiences a compression that is directed perpendicular to the level of the closure cover or perpendicular to the level of the seal. A friction or squashing of the seal in the transverse direction can considerably be avoided by means of the mentioned guide of the closure cover on the frame.

In a further embodiment, the closure cover is connected to the frame via at least one restoring element. The restoring element is configured to exert a restoring force onto the closure cover, which is directed against the closing force, which can be generated by the magnet device.

During the sealing closure of the closure or lock device, the magnet device acting between the counter plate and the closure cover counteracts the restoring force of the at least one restoring element. This has the advantage that the magnet device merely has to generate a force acting in a single direction, namely in the closing direction.

Thereby, the magnet device is designed to generate a closing force that is greater than the restoring force acting on the closure cover. In particular, the closing force that can be exerted onto the closure cover by the magnet device is greater than the sum of the restoring forces of all restoring elements, via which the closure cover is mounted onto the frame. The magnet device acts, so to say, against the restoring force of all the restoring elements to seal the opening. Since the closing force is greater than the sum of all restoring forces, this leads to a movement of the closure cover into the closed position when the magnet device is activated.

In contrast, in order to open the vacuum chamber, it is provided to reduce the closing force generated by the magnet device to at least a predetermined extent so that the effective closing force is lower than the sum of all the restoring forces of all restoring elements. As a result, the closure cover is set into the rest position on the frame via the at least one, typically via a plurality of restoring elements, in the case of a correspondingly lower or a completely lacking closure force of the magnet device. In this, the closure cover is either in a loose contact position to the seal of the counter plate or, at least one gap between the closure cover and the seal is available on the counter plate so that, in the case of the frame being in the contact position, the closure cover in the rest position is not in contact with the counter plate or the seal provided on the counter plate.

In a further embodiment, it is also provided that the at least one restoring element is an elastic restoring element. In this respect, the restoring element is elastically deformable and provides the required restoring force due to its elasticity. An elastic restoring element can, in particular, be designed as a single piece in the form of a single component, which is not subject to any relative movement between the frame or the closure cover apart from its elastic deformation. The one-piece design of a restoring element along with its elastic deformability has proven to be advantageous for adhering to the requirement of being free of particle contamination. In particular, a friction of the restoring elements with other components of the closure or lock device are prevented due to the elastic deformability of the at least one restoring element.

According to a further embodiment, the at least one restoring element has at least one restoring spring. The restoring spring can, for example, be designed in the form of a leaf spring. The restoring spring can, for example, extend between the opposite limbs of the frame. The restoring spring can be connected to the closure cover at approximately the centre between the frame limbs. By means of this, a centrical or face-centred mounting of the closure cover onto the frame can be achieved, which can have a favourable effect on the linear slidability of the frame.

According to another embodiment, the closure cover is arranged on the frame via a plurality of restoring elements spaced apart from each other. It is been proven beneficial if a plurality of equal-acting restoring elements and/or a plurality of restoring springs are arranged in a distributed manner across the surface of the frame, consequently being arranged across the surface of the closure cover. In this way, a restoring force that is homogeneous and defined to the furthest extent possible can be provided across the surface of the frame or across the surface of the closure cover.

According to a further embodiment of this, the sum of all of the restoring forces exerted upon the closure cover by all of the restoring elements is greater than the closure cover's weight force. Such a layout of the restoring elements, for example, makes a horizontal and, consequently, a reclining alignment of the counter plate possible, as well as making loading of the vacuum chamber from above possible. If the sum of all the restoring forces that can be exerted onto the closure cover is greater than the closure cover's weight force, the closure cover can also be pulled upwards by the restoring elements against its own weight force into the rest position on the carrier. Such a layout of the restoring forces has proven beneficial for flexibly using the closure or lock device and, in particular, for a great variety of different geometrical alignments of the closure or lock device.

According to another embodiment, the frame is arranged on the counter plate or on the vacuum chamber between an already mentioned open position and an already mentioned contact position in a swivelling or slidable manner. In the open position, the frame and the closure cover arranged on it release the opening of the vacuum chamber.

In particular, a sliding guide is suitable for a space-saving embodiment and an arrangement of the closure or lock device in the area of a substrate-treatment process station. Unlike swivel-mounted closure covers, the area, which is outside of the opening of the vacuum chamber and, so to say, within an extension of that opening, can be used to arrange other components of a process station and does not have to remain free as is the case with a swivel mount of the closure cover.

The closure cover can be mounted to the guide in a non-contact manner by means of one or a plurality of magnetic bearings. Thereby, a non-contact, and therefore low-wear and low-maintenance sliding of the closure cover against and relative to the counter plate is possible. Unlike a roller-bearing guide of the closure cover, no abrasion takes place in the case of a magnetic-bearing-based mounting of the closure cover. Required clean-room conditions and a required freedom of particle contamination in the area of the closure or lock device can therefore be easily maintained.

The magnetic bearings intended for the guide, similar to the magnet device provided for the closure or lock device, can each have an electromagnetic actuator and, hereby, a magnetically interactive counterpart, as well as a distance measuring device and a control circuit so that the closure cover is mounted at a predefined distance from the guide in an almost freely suspended manner and can be moved along the guide by means of the one or a plurality of magnetic bearings.

According to a further embodiment, in the case of a frame in the contact position, the closure cover can be transferred from a rest position into the sealing closed position relative to the frame by means of the magnet device. In the contact position, the frame abuts the counter plate or the vacuum chamber. Thereby, the closure cover substantially covers the entire opening. It seals the opening, however, it is still not gas-tight. In this respect, there can also be an air gap between the closure cover and the seal, which is typically arranged on the counter plate.

Only when the magnet device is activated and by the sliding movement of the closure cover perpendicular to the level of the closure cover or perpendicular to the level of the carrier and therefore typically also perpendicular to the opening level, which is controlled and managed by the magnet device, can the seal located between the counter plate and the closure cover be compressed as evenly as possible in the required manner.

In another embodiment, at least one spacer is arranged between the frame and the counter plate. In the contact position of the frame on the counter plate, there is the at least one spacer between the sides of the frame and the counter plate facing each other. Typically, a plurality of spacers are proved across the extent of the counter plate. Via the spacer or spacers, the frame braces itself on the counter plate upon reaching the contact position. The geometric design and arrangement of the at least one, preferably of a plurality of spacers, defines the contact position of the frame on the counter plate.

The extension of at least one or of a plurality of spacers perpendicular to the level of the frame or perpendicular to the level of the counter plate is at least as large as the sum of an adjustment range of the closure cover between the rest position and the closed position on the frame plus the thickness of the closure cover. Due to spacers measured in such a way, it is ensured that the closure cover arranged on the side of the frame facing the counter plate, for example, is out of contact with the counter plate or the seal provided on it if the frame with the closure cover on it in the rest position is transferred out of the open position into the contact position.

A premature contacting or sliding along of the closure cover at an area of the seal due to a swivelling or sliding movement of the frame can be prevented in this way.

According to an embodiment, the magnet device has at least one electromagnetic actuator arranged on one of the closure cover and counter plate and at least one counterpart arranged on the other of the closure cover and counter plate, which magnetically interacts with the electromagnetic actuator. The electromagnetic actuator can, for example, be arranged on the counter plate or embedded into the counter plate, while the counterpart can be arranged on the closure cover. Thereby, it is also conceivable that the counterpart is integrated into the closure cover or that the entire closure cover acts as a counterpart.

The counterpart or the closure cover is either designed to be ferromagnetic or permanently magnetic to engage in magnetic interaction with the electromagnetic actuator supplied with a corresponding control current. In a closed position of the closure cover on the counter plate, in which the closure cover completely covers the opening cross-section of the vacuum chamber, the electromagnetic actuator and a counterpart assigned to it are at least capable of covering in sections, for example, so that a sufficient closing force or opening force can be generated.

It is generally conceivable that the electromagnetic actuator of the magnet device is arranged on the closure cover, while the counterpart magnetically interacting with the electromagnetic actuator is arranged on the counter plate or formed on the counter plate Regardless of whether the electromagnetic actuator is arranged on the closure cover or on the counter plate, furthermore, at least one other permanent magnet can still be arranged on each component, at which the electromagnetic actuator is arranged, which can provide further support for the force generated by the electromagnetic actuator. Thereby, for example, the closure cover can be kept shut without power so that the coil of the actuator can be supplied with a considerably lower level of current strength. Heat loss of the coil and problems associated herewith with regard to cooling or thermal expansion can thereby be decreased or even eliminated.

According to another embodiment, an elastically compressible seal enclosing the opening can be arranged on the closure cover or on the counter plate within an intermediate space between the sides of the closure cover and the counter plate facing each other in a closed position of the closure cover. The seal can be arranged, for example, on the counter plate. For this purpose, the counter plate can have a groove surrounding the opening of the vacuum chamber, in which the circumferential seal is arranged. In an uncompressed original state, the thickness or the diameter of a seal section is greater than the depth of the groove accommodating the seal so that a part of the seal at least slightly protrudes from the side of the counter plate facing the closure cover, consequently with the contact surface formed by the counter plate. By means of that embodiment, the closure cover can end up resting on the seal in a sealing manner without the metal components of the counter plate and the closure cover touching each other.

The sides of the closure cover and the counter plate facing each other are typically designed as level of contact surfaces at least in sections, which, in the closed position, extend substantially perpendicular to the direction (z) specified by the geometry of the opening of the vacuum chamber or perpendicular to a closing direction, in which the closing force generated by the magnet device acts.

The seal is typically made of an elastomer and has an elasticity and/or compressibility suitable for the respective intended purpose. By means of the distance-dependent regulation of the closing force of the magnet device, it is also conceivable to use different seals with regard to their elastic or mechanical properties, each being used for different applications of the closure or lock device. By means of the distance-dependent regulation of the closing force, the closure or lock device can adapted to different or varying elastic properties of the seal provided. The seal can be designed as an O-ring-like seal, consequently being a circumferential sealing ring, which is closed in the circumferential direction.

Although the seal is preferably arranged within a groove of the counter plate and the closure cover, which interacts therewith, is designed without a seal, reverse embodiments are also conceivable, wherein the seal is arranged on an inner side of the closure cover, in particular, within a groove of the closure cover and wherein the counter plate is designed without a seal.

According to another embodiment, the closure or lock device has at least one distance measuring device to measure a distance between the closure cover and the counter plate. By means of the distance measuring device, a distance, at least at points, can be measured between the closure cover and the counter plate in the direction of the closing force generated by the magnet device. The distance between the closure cover in the counter plate is a measurement for the currently predominant compression or elastic deformation of a seal provided between the counter plate and the closure cover, provided that the closure cover rests above the seal on the counter plate. Consequently, the degree of elastic deformation of the seal can be measured by means of the distance measuring device.

Furthermore, for the closure or lock device, it is provided that the magnet device can be regulated by the distance measuring device depending on the distance measured between the counter plate and the closure cover. By means of the distance-dependent regulation of the magnet device provided in this respect, different closing forces depending on the distance at hand can be generated so that, for example, the seal provided between the counter plate and the closure cover can be compressed to the required extent. By means of the distance measuring device and the back-coupling to the at least one magnet device provided in this respect, a variety of different states of the closure or lock device can be detected.

For example, by means of the distance measuring device, it can be measured if and to what extent the counter plate and the closure cover abut each other in a sealing manner. If the distance should be approximately above a maximum value provided for an adequate seal, by means of the adjustable magnet device, the closing force can, for example, be incrementally increased until the distance falls below the maximum permissible maximum distance.

In the opposite case, it is also conceivable that, in the case of detecting or measuring a distance between the counter plate and the closure cover that is too small, a direct contact of the counter plate, which is typically made of metal, and the closure cover must be feared. In particular, due to reasons of a required freedom of particle contamination in the ambient environment of the vacuum chamber, this must absolutely be avoided. In such a case, the closing force level can be incrementally reduced until a minimum permissible distance between the closure cover and the counter plate is exceeded.

Thereby, by means of the distance-dependent regulation and control of the magnet device, different or temporally varying pressure levels within the vacuum chamber can also be responded to. By means of a pressure differential between the interior space of the vacuum chamber and the ambient environment or by means of a pressure differential on the side of or beyond the closure cover, a closing force or opening force per se can already be present on the closure cover. By means of the distance-dependent adjustable magnet device, varying pressure differentials on the opposite sides of the closure cover can be compensated for.

Furthermore, according to a further embodiment, at least one electronic control circuit is provided, which is coupled with the distance measuring device and with the at least one magnet device and is configured to maintain and/or to set a predetermined distance between the counter plate and the closure cover. The control circuit typically has a setpoint device, by means of which the distance signals, which can be generated by the distance sensor, are compared with a predetermined target value. By comparing the target value and the current value, a controller downstream from the setpoint device can generate a control signal to control the magnet device, in particular, to control the electromagnetic actuator.

Each control signal that can be generated by the controller can be supplied to the electromagnetic actuator, typically via an amplifier. By means of the electronic control circuit, an active and automatic regulation of the closing force can be implemented. In this way, a dynamic and situation-related response to any sudden or continuous changes of the operating or ambient conditions can be carried out, such as a change of the pressure differential between the interior space of the vacuum chamber and the ambient environment. By means of the control circuit coupling the distance measuring device and the magnet device with each other, a required distance between the counter plate and the closure cover and thereby, also a required pressing force of the closure cover as well as a compression of a seal provided between the counter plate and the closure cover associated therewith can be brought about and maintained in a controlled manner.

According to another embodiment, a plurality of magnet devices, each provided with their own distance measuring device, are arranged in a distributed manner across the extent of the opening and the extent of the flange-like counter plate, for example. By providing a plurality of magnet devices arranged in a distributed manner across the extent of the opening, a particularly even pressing and closing force can be set between the counter plate and the closure cover. Furthermore, by means of this, it makes it possible to compensate for any deformations or manufacturing inaccuracies of the counter plate and/or the closure cover in a system-controlled manner.

Each of the distance measuring devices coupled with a magnet device respectively can, so to say, self-sufficiently maintain and set a predetermined distance between the counter plate and the closure cover at the location of the corresponding distance measuring device or magnet device. Pressure-dependent and inevitable very minimal deformations of the closure cover, which would otherwise lead to an uneven pressing or closing force of the seal can thereby be compensated for in an effective manner and an uneven gap size with respect to a varying distance across the extent of the opening between the closure cover and the counter plate can be countered.

Any load-dependent or manufacturing-related deformations or component tolerances can be compensated for in a system-controlled manner. By means of a plurality of magnet devices, each respectively provided with its own distance measuring device, different closing forces and contact pressures can be generated on a local level across the extent of the opening or across the extent of the counter plate so that, as a result, a homogeneous compression of the seal is achieved to the furthest extent possible and can be set in a controlled manner, which leads to a required tightness of the closure or lock device. Within the scope of practical application, that embodiment is particularly beneficial, namely, in particular, if at least one of the closure cover and the counter plate are not designed to be absolutely rigid and/or are subject to local load-dependent deformations.

By means of a plurality of magnet devices, each provided with a distance measuring device respectively, such effects can be eliminated and compensated for in a system-controlled manner. Even comparably large component tolerances or mechanical deformations can be accepted for the construction of the closure cover and/or counter plate so that for even comparably large-scale embodiments of the closure cover and the counter plate a comparably filigree construction can be provided with a comparably lower weight.

According to another embodiment of the closure or lock device, it is provided that magnet devices arranged in a distributed manner across the extent of the opening of the vacuum chamber or across the extent of the counter plate or across the extent of the closure cover are each coupled with their own control circuit. Thereby each of the magnet devices can, independently of each other, set and regulate the present distance or gap size between the closure cover and the counter plate at their respective positions. As a result, a processing of the obtainable distance signals from the respective distance measurement devices can take place at a local level within the area of the magnet devices and control circuits. By means of this, any data and signal lines can be reduced to a minimum, which can prove to be particularly beneficial for applications in the vacuum sector.

According to another embodiment, the magnet devices arranged in a distributed manner across the extent of the opening and/or the distance measuring devices assigned to the magnet devices are coupled with a central control system. The central control system can be provided instead of a local control circuit or, however, in addition to the respective magnet device and to the related control circuit assigned to the distance sensor. By means of a central control system, which is, for example, coupled with all control circuits of all magnet devices with data connections, a synchronous control of the control circuits can take place in a particularly simple manner.

For example, the central control system can be coupled with the setpoint device of the individual control circuits respectively so that, by means of the central control system, a distance to be maintained between the counter plate and the closure cover can be simultaneously transferred to all control circuits. By means of the central control system, the user of the closure or lock device obtains an operating element that is particularly easy to operate, with which a distance to be maintained or a corresponding gap size between the closure cover and the counter plate can be synchronously or simultaneously set for all control circuits and magnet devices.

For each of the various embodiments of the closure or lock device, diverse distance measuring devices can be provided. The distance measuring device can, for example, have one or a plurality of distance sensors based on an optical, magnetic or capacitive measurement principle. In particular, sensors are used that are based on an inductive measurement principle or based on eddy currents. The distance sensor is particularly arranged in close proximity to the magnet device, in particular, in direct proximity to the electromagnetic actuator or to the counterpart of the magnet device so that a higher degree of co-location can be achieved to the furthest extent possible. The directly adjacent or even covering arrangement of the distance measuring device and the magnet device contributes to improving measurement and control accuracy. The distance sensor can, in particular, be arranged on the counter plate and therefore measure a distance, in particular, a gap size between the counter plate and the closure cover. A distance sensor arranged on the counter plate is, in particular, configured to measure the distance from a defined reference surface or a reference point of the closure cover in a precise manner, typically with an accuracy within the sub-millimetre or in the micrometre range.

DETAILED DESCRIPTION

The closure and lock device10shown as a cross-section inFIG. 1is provided for arrangement at an opening14of a vacuum chamber12. The closure or lock device10has a counter plate16, which is typically connected to the wall11of the vacuum chamber12schematically indicated inFIG. 1. The counter plate16can be arranged flush with the opening14of the vacuum chamber12on the wall11or as an integral component of the vacuum chamber12. In this respect, the counter plate16can also have an opening14, which can typically coincide with the opening of the vacuum chamber12.

As is evident in the overview inFIG. 2, 3, as well as6to8, the considerably level closure cover18in this embodiment is mounted to a frame15by means of a plurality of restoring elements82in a slidable manner. Thereby, the slidability and the deflection of the restoring elements82result from a comparison ofFIGS. 7 and 8. The frame15itself is, for example, swivel-mounted to the counter plate16. InFIGS. 2 and 3, a corresponding swivel or hinge axis80is shown. In the embodiment inFIGS. 4 and 5, the frame15is linearly mounted to the counter plate16in a sliding manner.

The side19facing the counter plate16of the closure cover, consequently the inner top surface81is substantially level. In the rest position U of the closure cover18relative to the frame15shown as an example inFIG. 7and in the case of the frame15in the contact position K located on the counter plate16, the top surface81is aligned substantially parallel to a level of the seal22, which is located in the groove20on the side17of the counter plate16facing the closure cover18.

In a closed position28shown inFIG. 8, the closure cover18seals the opening14in a gas-tight and vacuum-tight manner. Furthermore, the counter plate16and the closure cover18are provided with at least one magnet device30, by means of which a closing force (C) can be exerted on the closure cover18.

The counter plate16can have a flange-like geometry and, in particular, have a seal22on a side17facing the closure cover18and acting as a contact surface, which extends around the opening14, typically in the area of an opening boundary of the counter plate16. In the present disclosure, the seal22made of an elastic and deformable material is arranged in a surrounding groove20of the counter plate16. However, it can also be arranged within a corresponding groove of the closure cover18or in an intermediate space25between the closure cover18in the counter plate16.

Upon reaching a closed position S shown inFIG. 8, the seal22is deformed between the closure cover18in the counter plate16and squashed in such a way that the opening14is sealed in a gas-tight manner.

By means of the magnet device30, a closing force (C) on the closure cover18can be exerted in the insertion direction or closing direction (z). The closing force (C) is typically aligned perpendicular to the level (x, y) or perpendicular to the contact surface or to the side17of the counter plate16. The closure cover18also has a side19facing the counter plate16, which also acts as a contact surface. The sides17,19facing each other in the closed position28of the counter plate18and the closure cover19are aligned parallel to each other, at least in sections.

The respective contact surfaces of the sides17,19corresponding to each other extend in an x-y plane.

In the present disclosure, the magnet device30has at least an electromagnetic actuator32arranged on the counter plate16as well as a counterpart34arranged on the closure cover18, which magnetically interacts with the electromagnetic actuator32. The counterpart34is designed as a permanent magnetic or ferromagnetic component, which is either arranged on the closure cover18or embedded into the closure cover18. It is also conceivable that the closure cover18itself includes a permanent magnetic or ferromagnetic material, at least in sections, or at least in areas or is completely made of such a material.

By powering or by applying electrical power to a coil33of the electromagnetic actuator32, an attractive or repulsive force can be exerted on the closure cover18. By regulating the current strengths or by varying the control signal, the closing force (C) generated by the magnet device30can be varied according to the requirements at hand.

Furthermore, the closure or lock device10optionally has a distance measuring device40, by means of which a distance41between the closure cover18and the counter plate16, in particular a distance between the sides19,17of the closure cover18and the counter plate16facing each other can be measured in a determinable and quantitative manner. In the present disclosure, the distance measuring device40has a distance sensor42arranged on the counter plate16, which measures a distance41in the closing direction (z) between the counter plate16and the closure cover18. By means of the distance measuring device40, thereby, the magnet device30can be regulated, in particular the closing force (C) generated by it, depending on the distance. In particular, it is provided that, by means of a distance-dependent regulation of the magnet device30, the distance41between the closure cover18and the counter plate16can be set to a predetermined extent in a precise manner.

For the distance-dependent regulation, in particular, a control circuit45is provided, which couples the magnet device30with the distance measuring device40. The control circuit45has a setpoint device44, which is connected to the distance sensor42on a data/technical level. The setpoint device44receives the distance signals provided by the distance sensor42and compares these with a predefined or a variably specifiable target value from a central control system. The actual and target value are compared with each other in the setpoint device44.

A comparison signal resulting from this is then supplied to a controller46, which generates a control signal provided to control the electromagnetic actuator32. That control signal that can be generated by the controller46can be supplied to the electromagnetic actuator32via an amplifier48.

The amplified control signal, which can be supplied to the coil33of the electromagnetic actuator32is calculated and determined in such a way that a predetermined distance41between the counter plate16and the closure cover18is maintained and that, in the case of deviations of a required distance, the force generated by the magnet device30can be dynamically adapted to maintain the distance41.

All electronic components of the control circuit, meaning the amplifier48, the controller46, the setpoint device44, and, if applicable, also the distance sensor42can be accommodated altogether on a single PCB, for example, in the form of an integrated control circuit. The space required for a corresponding electronic unit and the wiring effort associated therewith can be minimized in this respect.

In addition to the coil30, to which electrical signals can be applied, the electromagnetic actuator32typically has a ferromagnetic core, for example an iron core. The electromagnetic actuator32can be designed as an electromagnet, however in a variety of different ways, for example, also as a Lorentz or voice-coil actuator. In contrast to an electromagnet, the latter can generate not only attractive, but also repulsive forces between the electromagnetic actuator and the counterpart.

The groove31intended to hold the electromagnetic actuator32or its coil33has to be covered and/or sealed facing the counterpart34for reasons relating to vacuum suitability. A cover21provided for this is typically made of a magnetically permeable material or out of the non-magnetic or only weakly magnetic material. The cover21can act almost as a closure for the groove31and can be designed as such. By means of separate seals, which are not explicitly shown in the present disclosure, the cover21is arranged over or in the groove31in a sealing manner. The cover21can, in particular, be integrated into the side17facing the counterpart34in a flush manner, consequently into the contact surface of the counter plate16or the closure cover18. For the sake of clear illustration, the cover21inFIG. 1is only shown on the right side of the counter plate16. Each of the magnet devices30arranged in a distributed manner across the extent of the opening14can be regulated according to the distance41predominant within their range between the counter plate16and the closure cover18so that a distance41remaining the same or maintained within slight tolerances can be set across the entire outer extent of the opening14.

As is furthermore shown inFIG. 1, there is at least one spacer24between the side17,19of the counter plate16and the closure cover18facing each other, which acts as an end-stop for the frame15.

In the uncompressed state of the seal22, as shown inFIG. 7, the seal22protrudes from the side17of the counter plate16at least slightly.

In the rest position U of the closure cover18relative to the frame15and the contact position K of the frame15relative to the counter plate16shown inFIG. 7, there is an air gap between the closure cover18and the counter plate16or between the closure cover18and the seal22. It can also be provided that the closure cover18abuts the seal22in that rest position U without being compressed and therefore in a relatively loose manner.

Upon activating the magnet device30, the components of which are only schematically shown inFIG. 6-8in comparison to the illustration according toFIG. 1, the closure cover18experiences a shifting movement compressing the seal22according to a closing force C acting upon it. The compressed seal22′ is indicated inFIG. 8. In the present embodiment, the closing force C interacts with the weight force G of the closure cover18. The closing force C acts against a restoring force R of individual restoring elements82. The restoring elements82are, as is evident inFIG. 3, designed as leaf springs83in the present disclosure.

The frame15is designed as a circumferential closed frame. It has two longitudinally extending limbs85,86, which run substantially in parallel, which are connected to each other at their longitudinal ends via had sections87,88on the end sides. Roughly centred between the head sections87,88a connection bridge89is provided, which connects both limbs85,86again on a structural level and, in this respect, increase the stability and the stiffness of the frame15. The leaf springs83are arranged in pairs. Opposite ends of the leaf springs82are arranged on the opposite limbs85,86. The leaf springs83are connected to the closure cover18at approximately the centre between the limbs85,86. A deflection of the closure cover18perpendicular to the level of the frame15, consequently parallel to the surface normal N of the closure cover18by means of the magnet device30therefore takes place against the restoring force R generated by the restoring springs83.

As is best evident fromFIGS. 6 and 7, a plurality of spacers24are arranged in a distributed manner across the extent of the opening14on the side17of the counter plate16facing the closure cover18. The spacers24are typically made of plastic, in particular, made of a high temperature resistant plastic, for example, out of polyether ether ketone (PEEK), which has only a slight or unnoticeable tendency to outgas, even under vacuum conditions.

In the contact position K of the frame15on the counter plate16, the frame15rests on the spacers24with its underside facing the opening14. Thereby, the spacers24form a type of end-stop for the swivel movement of the frame15. Corresponding to the arrangement of the spacers24on the counter plate16, on the outer edge of the closure cover18, corresponding recesses23are provided, which are interspersed with spacers24when assuming the contact position K. The recesses23allow for large-scale covering of the opening14by the closure cover18without obstructing a frame support arranged as close as possible on the opening14, or the frame15resting on the counter plate16.

As is evident fromFIG. 7, there is a defined gap between the closure cover18in the seal22in the contact position of the frame15and the rest position U of the closure cover18shown there. By activating the magnet device30, the closure cover18is pulled toward the counter plate16according to the closing force C. As a result, the restoring elements82are deflected toward the counter plate16. They provide a restoring force R, which permanently acts on the closure cover18. In the case of decreasing closing force or in the case of deactivating the magnet device30, the restoring elements82and the restoring springs83lead the closure cover18out of the sealing closed position S, as is shown inFIG. 8, thereby compressing the seal22, back into the rest position U again.

Movably mounting the closure cover18to the frame15is of an advantage in this respect, thereby being able to exert relatively high closing forces onto the closure cover18. Due to movably mounting the closure cover18against the frame15, those forces are however not transferred to the frame15. As a consequence, a hinge90formed by the swivel access80does not have to be able to absorb any of the closing forces generated by the magnet device30. The mechanical stress on the frame15is primarily only present due to the restoring force R which is transferred from the deflected restoring elements82between the closure cover18in the closed position S onto the frame15. Once the closure cover18is in the closed position S shown inFIG. 8, an increase of the closing force C only has slight or no mechanical effects on the frame15. InFIGS. 4, and 5, an alternative embodiment of the present invention is shown. In contrast to the embodiment according toFIGS. 2, 3 and 6, the frame15there is mounted in a slidable manner against the counter plate16and against the vacuum chamber12.FIG. 4shows the frame15with the closure cover18arranged on it in an open position, whileFIG. 5shows the frame15and the closure cover18in the contact position K or the closed position S. The frame15is mounted in a slidable manner along the extended guides62,64above and below, or on the opposite head sections87,88.

The guides62,64, which are designed as linear sliding guides, extend parallel to the level of the counter plate16of the frame15and/or of the closure cover18. Due to the closing movement of the closure cover18the guides62,64are arranged a sufficient distance away from the counter plate16in order to allow for a non-contact sliding of the closure cover18against the counter plate16, in particular also against the seal22provided on the counter plate16, which at least slightly protrudes from the level of the counter plate16.

The linear guides62,64can be designed as non-contact guides. A plurality of magnetic bearings60can be arranged in the area of the guides62,64.

Similar to the magnet devices30, the individual magnetic bearings60can each have a distance sensor (not shown separately in the present disclosure), a control circuit, as well as an electromagnetic actuator61, which can be controlled via the distance sensor and the control circuit which magnetically interact with a counterpart63. In this way, a required suspended state of the closure cover18on the guides62,64can be achieved. A non-contact mounting of the closure cover18on the guides62,64is of a particular advantage in avoiding contamination and wear in the area of the vacuum chamber12. In this case, a plurality of electromagnetic actuators61are provided along the guide62, which successively engage with the counterparts63arranged on the frame15in the case of sliding the frame15.

Thereby, reverse arrangements are both equally within the scope of the present invention. For example, one or a plurality of actuators62can be arranged on the frame15or on the closure cover18while counterpart63magnetically interacting therewith is arranged in a stationary manner on the linear guide62,64designed as a guide rail.

InFIG. 4, the frame15and the closure cover18are shown in the open position O, in which the closure cover18is outside of the area of the opening14of the counter plate16.

Thereby, the mounting of the closure cover18to the frame15has the effect of providing support for a type of parallel displacement of the closure cover18from the rest position U into the closed position S so that no relative movements of the closure cover18and the seal22occur in the plane of the closure cover (X, Y) to the furthest extent possible. Such shear movements could otherwise lead to the wear of the seal22and at least minor contamination of ambient environment of vacuum chambers12.

The non-contact mounting of the closure cover18to the guide62,64takes place via the frame15designed in a slide-like way and connected to the closure cover18. One of the components of the respective magnetic bearing60, i.e. a component of electromagnetic actuator61and a counterpart63, is arranged on the guide62,64in a stationary manner while the other component of the actuator61and the counterpart63is arranged on the frame15. For example, a linear motor68is provided to shift the closure cover18and the frame15along the guide62,64, by means of which the closure cover18can be moved between the open position0and the contact position K against the counter plate16.