Positioning stage with solid body spring suspension

Abstract

The present disclosure provides a positioning stage capable of positioning objects with nanometer scale accuracy. The positioning stage includes a base and a carriage displaceable relative to the base, and a stick-slip drive acting between the base and the carriage to produce a translatory movement between the base and the carriage. The stick-slip drive comprises a piezoelectric stack and an axis. One or more solid body springs are coupled to the base and the stick-slip drive. The axis is connected to the base via the one or more solid body springs, which extend in a direction parallel to the axis. The solid body springs are thin solid body strips realized in a folded geometry and have thinned sections. The solid body springs, the axis, and the base are fabricated from one solid work piece.

Description

POSITIONING STAGE WITH SOLID BODY SPRING SUSPENSIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Application No. 63 / 634,993, titled Positioning stage with high mechanical stiffness and high thermal conductance, filed April 17, 2024, which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to positioning stages for precise object manipulation, and more particularly to a positioning stage with enhanced mechanical stability and thermal conductance utilizing solid body spring suspension.BACKGROUND

[0003] Positioning stages are widely used in various industrial and scientific applications for precise manipulation and positioning of objects. These devices play a crucial role in fields such as microscopy, semiconductor manufacturing, optical alignment, and scientific research where nanometer-scale accuracy is required.

[0004] Conventional positioning stages often employ piezoelectric actuators to achieve high- precision movement. These actuators utilize the piezoelectric effect, where certain materials change shape when an electric field is applied. By controlling the voltage applied to piezoelectric elements, positioning stages can produce small, controlled displacements.

[0005] One common design for positioning stages is the stick-slip drive mechanism. This approach uses friction and inertia to generate incremental movements. A typical stick-slip drive consists of a base, a movable carriage, and an actuator that produces rapid oscillations. During slow extension of the actuator, friction causes the carriage to move with it. Rapid contraction then causes the carriage to slip relative to the actuator, resulting in net displacement.

[0006] While stick-slip drives can achieve fine positioning, they face challenges in maintaining their performance when operated under vacuum and cryogenic conditions. The friction coefficient of the friction interface between the carriage and actuator sensitively depend on various parameters, such as surface roughness, types of materials used, and the presence oflubricant media. Additionally, the use of different materials with varying thermal properties can affect the performance and functionality of the stick-slip drive when temperature changes.

[0007] Positioning stages used in sensitive applications like microscopy or cryogenic experiments have stringent requirements for mechanical stability. Even small vibrations or thermal drift can significantly impact measurement accuracy. There is an ongoing need for positioning stage designs that provide enhanced rigidity and consistent performance across a range of operating conditions.

[0008] Thermal management is another consideration for positioning stages, particularly those used in temperature-controlled environments. For example, some of the microscopy applications are often conducted under cryogenic conditions of 4 Kelvin or below. The successful microscopy operation requires an efficient cooling of the sample and probe to the base temperature of the cryogenic system. The efficient cooling of samples and / or probes attached to a translation stage to the experimental base temperature requires an unobstructed flow of heat across the positioning stage, unless auxiliary thermal straps can be used. Indeed; heat generated by actuators or transferred through the stage structure can affect both the positioning accuracy and the sample being manipulated. Improving thermal conductance through the stage assembly can help maintain temperature uniformity and stability.

[0009] As the demands for precision in scientific and industrial processes continue to increase, there remains room for improvement in positioning stage technology. Advancements that enhance mechanical stability, thermal performance, and overall reliability would benefit a wide range of applications requiring accurate object manipulation at the micro and nanoscale.SUMMARY

[0010] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0011] According to an aspect of the present disclosure, a positioning stage is provided. The positioning stage includes a base, a carriage displaceable relative to the base, a stick-slip drive acting between the base and the carriage to produce translatory movement between the base and the carriage, and a solid body spring coupled to the base and the stick-slip drive. The stick-slipdrive comprises a piezoelectric stack and a metal axis operably coupled to the piezoelectric stack, the piezoelectric stack including a piezoelectric element.

[0012] According to other aspects of the present disclosure, the positioning stage may include one or more of the following features. The solid body spring may include a plurality of solid body springs and / or the piezoelectric element may include a plurality of piezoelectric elements. The solid body spring may extend in a direction parallel to the metal axis. Each solid body spring may be realized in a folded geometry. Each solid body spring may have a thicker section and a thinner section. The solid body spring, the metal axis, and the base may be fabricated from one solid work piece. At least one solid body spring may be connected to the base via the piezoelectric element. A first surface of the piezoelectric element may be coupled to the base and with a second surface opposite the first surface may be connected to one or more solid body springs or the metal axis. The metal axis may be held free of bearings and fastenings other than its direct coupling to one or more solid body springs. The metal axis may be coupled to the piezoelectric element and to the solid body spring.

[0013] The base may comprise an outer housing defining an internal volume of space, the outer housing being connected to two solid body springs, the two solid body springs being mutually connected by the metal axis within the internal volume of space, where the outer housing having a substantially rectangular or square shape when viewed from above. The piezoelectric element may be fixed to the base. The piezoelectric element may be fixed to the outer housing. The base and the stick-slip drive may be configured such that a base plate is connected to the metal axis via at least one solid body spring, the base plate having a substantially rectangular or square shape when viewed from above. The piezoelectric element may be installed between the base and the solid body spring such that it causes a pretension in the solid body spring.

[0014] The positioning stage may further comprise one or more ceramic plates coupled to the metal axis. The carriage may include two clamps, the two clamps being disposed around a portion of the one or more ceramic plates. A surface of each of the two clamps that is configured to face towards the metal axis may be coated in a noble metal, where ceramic plates may be attached to the metal axis. In some aspects, ceramic plates may be attached to a surface of each of the two clamps configured to face towards the metal axis, and where the surface of the metal axis may be coated in a noble metal.

[0015] According to another aspect of the present disclosure, a system is provided. The system includes a plurality of positioning stages operably coupled together, the plurality of positioning stages including a first positioning stage operably coupled to a second positioning stage, each positioning stage having a metal axis oriented in a different direction.

[0016] According to another aspect of the present disclosure, a method for repositioning a positioning stage is provided. The method includes providing a positioning stage comprising a stick-slip drive containing a piezoelectric element coupled to a metal axis. The stick-slip drive may operably couple a base and a carriage. The metal axis, solid body spring, and the base may be formed of a single integral component. The carriage may include two clamps that are disposed around the metal axis. The method further includes generating translatory motion of the carriage relative to the base by expanding and / or contracting the piezoelectric element.

[0017] The foregoing general description of the illustrative embodiments and the following detailed description thereof are merely exemplary aspects of the teachings of this disclosure and are not restrictive.BRIEF DESCRIPTION OF FIGURES

[0018] Non-limiting and non-exhaustive examples are described with reference to the following figures.

[0019] Figure 1A illustrates an isometric view of a positioning stage, according to aspects of the present disclosure.

[0020] Figure IB illustrates a top view of the positioning stage of FIG. 1A, according to aspects of the present disclosure.

[0021] Figure 1C illustrates an exploded view of the positioning stage of FIG. 1A, according to aspects of the present disclosure.

[0022] Figure ID illustrates a side view of a solid body spring, according to aspects of the present disclosure.

[0023] Figure 2A illustrates an isometric view of another embodiment of a positioning stage, according to aspects of the present disclosure.

[0024] Figure 2B illustrates a bottom view of the positioning stage of FIG. 2A, according to aspects of the present disclosure.

[0025] Figure 2C illustrates an exploded view of the positioning stage of FIG. 2A, according to an embodiment.

[0026] Figure 3 illustrates a system, combining vertical and horizontal translation stages.DETAILED DESCRIPTION

[0027] The following description sets forth exemplary aspects of the present disclosure. It should be recognized, however, that such description is not intended as a limitation on the scope of the present disclosure. Rather, the description also encompasses combinations and modifications to those exemplary aspects described herein.

[0028] Existing translation stages often face challenges in achieving optimal performance across a range of operating conditions. Many commercially available systems may struggle to maintain consistent positioning accuracy when subjected to temperature fluctuations or mechanical stresses. This can lead to drift or hysteresis effects that compromise the reliability of fine positioning operations. Additionally, some current designs may suffer from limited stiffness in certain axes, potentially allowing unwanted vibrations or deflections that can impact measurement or manufacturing precision.

[0029] In some cases, translation stages may exhibit reduced performance at the extremes of their operating range. This can manifest as decreased resolution or repeatability when approaching the limits of travel, potentially constraining the effective working area of the stage. Furthermore, some existing designs may face challenges in scaling to accommodate larger payloads or longer travel distances without sacrificing precision or speed.

[0030] Thermal management presents another area where current translation stage technology may have room for improvement. Heat generated by actuators or transferred through the stage structure can lead to thermal gradients that affect positioning accuracy. This issue may be particularly pronounced in applications requiring extended operation times or those conducted in temperature-sensitive environments. Additionally, some existing designs may struggle to provide efficient heat dissipation, potentially limiting their suitability for high-duty cycle operations or use in vacuum environments.

[0031] Many commercially available positioning stages employ glue joints to fix the axis to the piezoelectric stack and the piezoelectric stack to the base. These glue joints are mechanical weak links that further degrade when undergoing thermal cycling. For this reason, the applicationof linear and torsional forces, such as occurring when loading a specimen with a mechanical transfer arm to a microscope, puts the positioning stage at risk of mechanical failure. Hence, the use of commercially available positioning stages in various types of microscopy applications is limited.

[0032] Existing commercially available positioning stages are characterized by comparably small lowest mechanical resonance frequencies on the order of 2 kHz or less. When a load is attached to the movable carriage, the lowest resonance frequency is further decreased to approximately 500 Hz. Hence, existing positioning stages are particularly susceptible to external mechanical vibrations that can excite their mechanical resonance modes. For this reason, they are not suited for the use in microscopy and other applications that require lowest mechanical vibrations.

[0033] Finally, commercially available positioning stages are commonly assembled from a metallic base, a piezoelectric stack made from PZT material, a ceramic axis often made from amorphous AI2O3, and a movable metallic carriage, which is in mechanical contact to the axis. Both PZT and amorphous AI2O3 have a very low heat conductivity (Ct) compared to metals. PZT has a Ct of approximately 1 W / m • K, AI2O3 has atof approximately 20 W / m • K, and for comparison copper has t of approximately 400 W / m • K at room temperature. At cryogenic temperatures of 4 K or below, heat conductivity of PZT and AI2O3 is reduced even further, owing to their ceramic nature. For this reason, existing positioning stages are not suitable for applications that require the efficient removal of static heat loads, such as microscopy applications conducted under cryogenic conditions, and applications that generate dynamic heat loads, such as laser sources and laser beam guides used in lithographic and optoelectronic instruments.

[0034] The present disclosure relates to positioning stages capable of precise positioning with nanometer-scale accuracy even at very low temperatures. In some cases, a positioning stage may include a base and a carriage that is displaceable relative to the base. The positioning stage may utilize a stick-slip drive acting between the base and the carriage to produce translatory movement.

[0035] In some implementations, the stick-slip drive may comprise a piezoelectric stack and an axis operably coupled to the piezoelectric stack. The piezoelectric stack may include a piezoelectric element that expands and contracts to drive the movement.

[0036] The positioning stage may also include a solid body spring coupled to the base and the stick-slip drive. This configuration may provide mechanical stability while allowing controlled movement of the carriage relative to the base.

[0037] The positioning stage described herein may be suitable for applications requiring high- precision positioning, such as in microscopy, semiconductor manufacturing, or scientific instrumentation. The combination of components allows for controlled linear motion with nanometer-scale accuracy.

[0038] In some cases, a positioning stage may be configured for vertical displacement of payloads. FIG. 1A illustrates an isometric view of such a positioning stage. The positioning stage may include a carriage 10 comprising two clamps 12, 14. The clamps 12, 14 may be configured to engage with the ceramic plates that may be coupled to a metal axis 30 in such a way that the stickslip motion can be realized (that is, the clamps cannot be rigidly affixed to the metal axis via, e.g., glue, welding, screws, etc.)

[0039] The clamps 12, 14, may be composed of any appropriate material. The clamps may be a metal. The clamps may be a ceramic.

[0040] The metal axis may be any appropriate metal. In some cases, the metal axis may be composed of materials suitable for cryogenic applications. Non-limiting examples of such materials include copper, beryllium copper, aluminum, stainless steel (particularly austenitic grades like 304 or 316), titanium, a nickel-iron alloy, phosphor bronze, brass, a nickel-cobalt alloy, niobium, molybdenum, or a combination thereof. These metals may be selected based on their thermal and mechanical properties at low temperatures, such as thermal conductivity, thermal expansion, and strength. In some implementations, the choice of metal for the axis may depend on specific application requirements, including the operating temperature range, thermal management needs, and mechanical stability considerations.

[0041] One or more ceramic plates should be disposed between the metal axis and the clamps, the ceramic plate may be coupled directly or indirectly with the metal axis or the clamps. In some aspects, a ceramic plate 20 may be disposed on the metal axis 30. In some implementations, the ceramic plate 20 may be glued to the metal axis 30. The ceramic may include, e.g., alumina (amorphous AI2O3) or sapphire (Crystalline AI2O3). The ceramic plate 20 may be polished to a surface roughness better than DIN ISO 1302 Nl, such as an arithmetic average Roughness value (Ra) of no more than 0.0.025 pm as measured using conventionally known techniques. Theclamps 12, 14 may include holes 16 that can accommodate fasteners. In some cases, the clamps 12, 14 may be joined by spring loaded screws secured inside the holes 16.

[0042] A surface configured to slidably interact with the ceramic plate may be coated. For example, in aspects where the ceramic plate is coupled to the metal axis, the surfaces 13 of the clamps 12, 14 that are configured to face the ceramic plates may be coated. The coating on the surfaces may be used to tune the performance of the stick-slip drive. Specifically, the sliding friction of the motion interface is an important factor that can be controlled based on the materials selected for the interface. In some instances, this is a metallic - ceramic interface. The sliding friction (and therefore the coefficient of friction) itself may be determined by the physics and chemistry at the interface. Non-noble metals will tend to form native surface oxides, and that native surface oxide will form ionic bonds with, e.g., the AI2O3 of the ceramic surface, resulting in more friction (a higher coefficient of friction). Noble metals (including, e.g., noble metal plating) tends not to form native surface oxides, so the chemical bonds do not form, resulting in a substantial reduction of the friction coefficient. As used herein, the term "noble metal" refers generally to those metals with positive standard electrode potentials, indicating they are difficult to oxidize and have little tendency to lose electrons. Such metals include, e.g., gold, silver, and the platinum group metals (platinum, palladium, rhodium, ruthenium, iridium, and osmium), and combinations thereof. In a preferred embodiment, noble metal - ceramic interfaces are used, and in a more preferred embodiment, a gold coating on the metal clamps or axis is used to interface with the ceramic plate.

[0043] The positioning stage may include a base 50 that can be secured using screws 60 to, e.g., an underlying substrate, device, etc. Separately, a hole 40 may be provided in the assembly, preferably in the metal axis, and more preferably oriented in an axial direction, for various purposes such as mounting or adjustment.

[0044] FIG. IB illustrates a top view of the positioning stage. In this view, the arrangement of the clamps 12, 14 in a parallel configuration can be observed. The ceramic plate 20 may be positioned between the clamps 12, 14 and the metal axis 30, and may be mounted on either the metal axis 30 or the clamps 12, 14. The metal axis 30 may extend through the central portion of the positioning stage.

[0045] FIG. 1C provides an exploded view of the positioning stage, revealing additional components.

[0046] As shown, the base may include a portion in the form of a base plate 51, that is substantially planar. There may be one or more portions 52 that extend outwards from an upper face 53 of the base place.

[0047] A piezoelectric stack 70 may be positioned between the base 50 and the metal axis 30. The piezoelectric stack 70 may include a one or more piezoelectric elements, and preferably, a plurality of piezoelectric elements. In some implementations, the piezoelectric stack 70 may be glued to the base 50. The piezoelectric stack may be coupled to the upper face 53 of the base plate 51.

[0048] The solid body springs 80 may connect the metal axis 30 to the base 50 along the direction of the actuation axis. As shown in FIG. 1C, the actuation axis 32 is the direction the clamps will move along the metal axis 30. As is known, a solid body spring (also called a flexure spring) is a type of spring that stores and releases energy through the elastic deformation of a solid material, rather than through the coiling or extension of wire as in traditional springs. Solid body springs may include various types such as leaf springs, cantilever springs, diaphragm springs, torsion bars, and notch hinges.

[0049] Referring briefly to FIG. ID, the solid body springs 80 may extend in a direction 86 parallel to the metal axis 30. In some cases, each solid body spring 80 may be realized in a folded geometry. A folded solid body spring (sometimes referred to as a folded flexure spring) generally refers to a specialized type of solid body spring that incorporates folded or pleated geometries to achieve specific mechanical properties within a compact form factor. As seen in FIG. ID, the solid body spring has a folded geometry. From an anchor end 181, there is a straight column portion 182 oriented in a direction 86 parallel to the metal axis, a first fold forming an outer truss (and a first folded layer 183) perpendicular to the direction 86 and extending from the straight column portion 182 outwards away from the center of the solid body spring, followed by another portion generally oriented in the direction 86 parallel to the metal axis, and finally another fold forming a second folded layer 184.

[0050] Each solid body spring 80 may have a thicker section and a thinner section - for example, there may be a first location having a first thickness 82, and a second location with a second thickness 84 that is smaller than the first thickness 82. In some instances, such thicknesses may be measured in, e.g., the direction 86 parallel to the metal axis. In some preferred embodiments, the thicker and thinner portions may be present in the second folded layer 184. Insome embodiments, a difference between a minimum thickness and a maximum thickness of the spring (e.g., first thickness 82 - second thickness 84) may be no more than 2 mm, no more than 1.5 mm, no more than 1 mm, or no more than 0.5 mm.

[0051] As will be understood, the exact dimensions may vary as appropriate to achieve the desired level of control, travel distance, etc., required by the device.

[0052] In some embodiments, the spring may have a total height (e.g., distance in the direction 86 parallel to the metal axis) of no more than 10 mm, no more than 9 mm, no more than 8 mm, no more than 7 mm, no more than 6 mm, or no more than 5 mm. In some embodiments, a separation 185 between each folded layer may be no more than 5 mm, no more than 4 mm, no more than 3 mm, no more than 2 mm, or no more than 1 mm.

[0053] The solid body springs offer significantly enhanced mechanically robustness, because they protect the positioning stage assembly from linear and torsional forces acting on the axis that, otherwise, could lead to the mechanical failure of the piezoelectric material or glue joints.

[0054] The solid body springs substantially enhance the mechanical stability of the positioning stage. The disclosed positioning stages are characterized by mechanical resonance frequencies larger than 7 kHz. Owing to the enhanced stiffness endowed by the solid body springs, the attachment of a load to the carriage only mildly influences this resonance frequency.

[0055] Under practical considerations, the installation of the piezoelectric element will cause small pretension on the solid body springs. This pretension supports a faster return of the axis to its rest position in the slip step of the stick-and-slip operation. This promotes are more efficient operation of the stick- slip drive.

[0056] The conduction of heat across the positioning stage is greatly enhanced. The solid body springs permit the direct transfer of heat from the axis to the base within one metallic component, benefitting from the substantial thermal conductivity of metals.

[0057] In some implementations, the solid body springs 80, the metal axis 30, and the base 50 may be fabricated from one solid work piece (e.g., they may form a single integral component). This configuration may provide enhanced mechanical stability and thermal conductivity.

[0058] The metal axis 30 may be coupled to the piezoelectric stack 70 and to the solid body springs 80. In some cases, the metal axis 30 may be held free of bearings and fastenings other than its direct coupling to the solid body springs 80.

[0059] A first surface of the piezoelectric stack 70 may be coupled to the base 50, and a second surface opposite the first surface may be connected to the solid body springs 80 or the metal axis 30. In some implementations, at least one solid body spring 80 may be connected to the base 50 via the piezoelectric stack 70.

[0060] The surfaces of the carriage 10 (such as surfaces 13 of the clamps 12, 14) that form the friction interface with the ceramic plate 20 may be polished to DIN ISO 1302 N4 or better, such as an arithmetic average Roughness value (Ra) of no more than 0.2 pm as measured using conventionally known techniques. This polishing may help ensure smooth and precise movement of the carriage 10 relative to the metal axis 30.

[0061] In operation, a constant or varying voltage signal may be applied to the piezoelectric stack 70. This voltage signal may cause the piezoelectric stack 70 to be maintained (e.g., if the voltage signal is held constant), expand (e.g., if the voltage signal increases) and / or contract (e.g., if the voltage signal decreases), driving the movement of the metal axis 30 relative to the base 50. The interaction between the clamps 12, 14 and the ceramic plate 20 on the metal axis 30 may enable controlled vertical displacement of the carriage 10 through a stick-slip mechanism.

[0062] In some cases, a positioning stage may be configured for horizontal displacement of payloads. FIG. 2A illustrates an isometric view of such a positioning stage. The positioning stage may include the carriage 10 (that may include a carriage plate 110 operably coupled to clamps 12, 14), that can be displaced relative to the base 50, to generate horizontal displacement of a payload. The base 50 may include mounting holes for securing screws 60 that allow attachment to a mounting surface. A hole 42 may be provided in the structure, which can be used for assembly or mounting purposes. Carriage plate 110 can be operably coupled to other components whose positioning is desirable to be controlled by the translation stage.

[0063] FIG. 2B illustrates a bottom view of the positioning stage. The positioning stage may include a clamp 12 that interfaces with the ceramic plates 20 attached to the metal axis 30. The metal axis 30 may be connected to the base 50 through the solid body springs 80.

[0064] The piezoelectric stack 70 may be positioned between the metal axis 30 and the base 50. The positioning stage may include screws 62 for adjustment purposes.

[0065] As shown here, in various embodiments, the base may have a rectangular or square shape, or a substantially rectangular or square shape, when viewed from above or below. Here, the term “substantially rectangular or square” generally refer to shapes that would qualify asrectangular or square using the ordinary meaning of such terms, except for having corners that do not qualify as right angles - e.g., rounded, chamfered, or beveled corners. As seen, the shape of the base in FIG. 2B could alternatively be considered octagonal, but - with the corner segments having lengths less than 25% of the length of the adjacent sides, the corner segments are considered here to be a chamfer, and therefore, the 2-D cross-section has a shape that is “substantially rectangular or square”.

[0066] FIG. 2C shows an exploded view of the positioning stage, revealing additional components. A clamp 14 may be designed to interact with the ceramic plates 20 on the metal axis 30. A hole 120 may be provided to allow for component assembly and adjustment. Control springs 130 may be included to provide controlled pressure between interfacing components. Here, the control springs 130 are used to control the force that clamps 12, 14 exert on the ceramic plates 20, and therefore, the force between the ceramic plates and the underlying metal axis.

[0067] In FIG. 2C, the base 50 may define an outer housing 54. The outer housing may have a substantially rectangular or square shape when viewed from above or below. The outer housing may define an internal volume of space 56, and various components, such as one or more solid body springs 80, and the metal axis 30, may be located within the internal volume of space.

[0068] In some implementations, the base 50 and stick-slip drive may be constructed in the form of a substantially rectangular or square shaped housing (e.g., when viewed from above, ignoring rounded, chamfered, etc. corners) connected to two solid body springs 80. The two solid body springs 80 may be mutually connected by the metal axis 30. In other cases, the base 50 and stick-slip drive may be constructed in the form of a rectangular or square shaped base plate connected to the metal axis 30 via at least one solid body spring 80.

[0069] The piezoelectric stack 70 may be fixed to the base 50. In some cases, the vertical extent of the piezoelectric stack 70 may slightly exceed the vertical void between the base 50 and the metal axis 30. This configuration may create a pretension in the solid body springs 80.

[0070] The installation of the piezoelectric stack 70 may be facilitated by exerting an outward pulling force on the solid body springs 80. This force may be applied via a screw secured to the hole 120 in the metal axis 30.

[0071] The friction force between the clamp 12 or 14 and the carriage 10 and the metal axis 30 may be adjusted by the control springs 130. These springs may control the force of the screwjoint realized between the clamp 12, 14, and the ceramic plates and metal axis, using the screws 62.

[0072] In operation, the piezoelectric stack 70 may drive the metal axis 30 relative to the base 50 (e.g., by causing the solid body spring 80 to flex based on the piezoelectric elements state). Specifically, a piezoelectric stack, fixated between the axis and the base, can displace the movable carriage in a bilinear motion along the axis with respect to the base via the application of transient voltage waveforms.

[0073] The interaction between the clamps 12, 14 and the ceramic plates 20 on the metal axis 30 may enable controlled horizontal displacement of the carriage 10 through a stick-slip mechanism. The solid body springs 80 may provide mechanical stability while allowing this controlled movement.

[0074] The operation of the positioning stage may be based on a stick-slip mechanism that enables precise translatory movement of the carriage relative to the base. In some cases, this mechanism may be driven by the piezoelectric stack 70, which may include one or more piezoelectric elements.

[0075] Referring to FIG. 1C and FIG. 2C, the piezoelectric stack 70 may be installed between the base 50 and one or more solid body springs 80. This configuration may cause a pretension in the one or more solid body springs 80. The pretension may enhance the responsiveness of the positioning stage to applied voltage signals.

[0076] In operation, a voltage signal, such as a ramping waveform, etc., may be applied to the piezoelectric stack 70. This voltage signal may cause the piezoelectric stack 70 to expand or contract as appropriate. The expansion and contraction of the piezoelectric stack 70 may drive the movement of the metal axis 30 relative to the base 50.

[0077] Conversely, during the fast rising or decreasing part of the voltage signal, the piezoelectric stack 70 may rapidly change length. Due to inertia, the carriage 10 may not be able to follow this rapid motion of the metal axis 30. Instead, the carriage 10 may remain in place, slipping relative to the ceramic plate 20 on the metal axis 30.

[0078] This alternating stick-slip motion may result in a net displacement of the carriage 10 relative to the base 50. By repeating this process, the positioning stage may achieve controlled linear motion with nanometer-scale accuracy.

[0079] The solid body springs 80 may play a crucial role in the operation of the positioning stage. These springs may provide mechanical coupling between the metal axis 30 and the base 50, allowing for controlled movement while maintaining stability. The solid body springs 80 may also help to return the metal axis 30 to its initial position after each cycle of the piezoelectric stack 70.

[0080] In some cases, the pretension caused by the installation of the piezoelectric stack 70 between the base 50 and the solid body springs 80 may enhance the performance of the positioning stage. This pretension may improve the response of the stick-slip drive to applied voltage signals, potentially resulting in more precise and reliable positioning.

[0081] The operation principles described may apply to both vertical and horizontal displacement configurations of the positioning stage, as illustrated in FIG. 1C and FIG. 2C respectively. The specific orientation of the components may be adapted to suit the desired direction of motion, while the fundamental stick-slip mechanism remains consistent.

[0082] It is envisioned that multiple translation stages may be combined. As shown in FIG. 3., a system may be provided, whereby a plurality of translations stages (e.g., translation stages 310, 320) may be operably coupled together. Each translation stage may have its metal axis oriented in a different direction. In some instances, each metal axis may be oriented in a direction orthogonal to every other metal axis in the system. For example, using the Cartesian coordinate system shown in FIG. 3, a two-stage system may be configured such that one stage may be configured to translate along the x-axis, while another may be configured to translate along the z- axis. Alternatively, the first and second translation stages may be configured to translate along the x-axis and y-axis, respectively. A three-stage system may be configured such that a first, second, and third stage may be configured to translate along the x-axis, y-axis, and z-axis, respectively.

[0083] A controller 330 (which may include electric circuits, a processing unit, memory, etc., as appropriate) may be used to control a power supply 340, which provides power to the translation stages 310, 320 via one or more wires 342. By controlling the voltage waveforms sent to the translation stage.

[0084] A method for repositioning a positioning stage may include, e.g., providing a positioning stage as disclosed herein. The positioning stage may be exposed to an atmosphere (or lack thereof) as desired, including, e.g., a vacuum, an inert atmosphere, a cryogenic atmosphere, etc. Translatory motion of the carriage relative to the base may be generated by expanding and / or contracting the piezoelectric element.

[0085] Several implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.

Claims

What is claimed is:

1. A positioning stage, comprising: a base; a carriage displaceable relative to the base; a stick-slip drive acting between the base and the carriage to produce translatory movement between the base and the carriage, the stick-slip drive comprising a piezoelectric stack and a metal axis operably coupled to the piezoelectric stack, the piezoelectric stack including a piezoelectric element; and a solid body spring coupled to the base and the stick-slip drive.

2. The positioning stage of claim 1 , wherein the solid body spring includes a plurality of solid body springs and / or wherein the piezoelectric element includes a plurality of piezoelectric elements.

3. The positioning stage of claim 1 or 2, wherein the solid body spring extend in a direction parallel to the metal axis.

4. The positioning stage of any one of claims 1-3, wherein each solid body spring is realized in a folded geometry.

5. The positioning stage of any one of claims 1-4, wherein each solid body spring has a thicker section and a thinner section.

6. The positioning stage of any one of claims 1-5, wherein the solid body spring, the metal axis, and the base are fabricated from one solid work piece.

7. The positioning stage of any one of claims 1-6, wherein at least one solid body spring is connected to the base via the piezoelectric element.

8. The positioning stage of any one of claims 1-7, wherein a first surface of the piezoelectric element is coupled to the base and with a second surface opposite the first surface is connected to one or more solid body springs or the metal axis.

9. The positioning stage of any one of claims 1-8, wherein the metal axis is held free of bearings and fastenings other than its direct coupling to one or more solid body springs.

10. The positioning stage of any one of claims 1-9, wherein the metal axis is coupled to the piezoelectric element and to the solid body spring.

11. The positioning stage of any one of claims 1-10, wherein the base is comprising an outer housing defining an internal volume of space, the outer housing being connected to two solid body springs, the two solid body springs being mutually connected by the metal axis within the internal volume of space, where the outer housing having a substantially rectangular or square shape when viewed from above.

12. The positioning stage of claim 11, wherein the piezoelectric element is fixed to the base.

13. The positioning stage of claim 11 or 12, wherein the piezoelectric element is fixed to the outer housing.

14. The positioning stage of any one of claim 1-13, wherein the base and the stick-slip drive are configured such that a base plate is connected to the metal axis via at least one solid body spring, the base plate having a having a substantially rectangular or square shape when viewed from above.

15. The positioning stage of any one of claims 1-14, wherein the piezoelectric element is installed between the base and the solid body spring such that it causes a pretension in the solid body spring.

16. The positioning stage of any one of claims 1-15, further comprising one or more ceramic plates coupled to the metal axis.

17. The positioning stage of claim 16, wherein the carriage comprises a carriage plate operably coupled to two clamps, the two clamps being disposed around a portion of the one or more ceramic plates.

18. The positioning stage of claim 17, wherein a surface of each of the two clamps that is configured to face towards the metal axis is coated in a noble metal and wherein ceramic plates are attached to the metal axis.

19. The positioning stage of claim 17, wherein ceramic plates are attached to a surface of each of the two clamps that is configured to face towards the metal axis and wherein the surface of the metal axis is coated in a noble metal.

20. A system, comprising: a plurality of positioning stages of any one of claims 1-19 operably coupled together, the plurality of positioning stages including a first positioning stage operably coupled to a second positioning stage, each positioning stage having a metal axis oriented in a different direction.

21. A method for repositioning a positioning stage comprising a stick-slip drive that includes a piezoelectric element coupled to a metal axis, the stick-slip drive operably coupling a base and a carriage, where the metal axis, solid body spring, and the base are formed of a single integral component, and where the carriage includes two clamps disposed around the metal axis, the method comprising: providing the positioning stage; and generating translatory motion of the carriage relative to the base by expanding and / or contracting the piezoelectric element.

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