EP3973622A1

EP3973622A1 - Biaxial positioning device

Info

Publication number: EP3973622A1
Application number: EP20731786.8A
Authority: EP
Inventors: Thomas Haase; Eric Köhler
Original assignee: Physik Instrumente PI GmbH and Co KG
Current assignee: Physik Instrumente PI GmbH and Co KG
Priority date: 2019-05-20
Filing date: 2020-05-20
Publication date: 2022-03-30
Also published as: WO2020233753A1; DE102019113296A1; US20220320987A1

Abstract

The invention relates to a biaxial positioning device comprising: a stationary base element (2); a first positioning element (3) movably mounted relative to the base element (2) along a first direction by means of a first guide device; a second positioning element (4) movably mounted relative to the first positioning element (3) along a second direction, which is different to the first direction, by means of a second guide device; a first drive for adjusting the first positioning element (3) along the first direction of movement; and a second drive for adjusting the second positioning element (4) along the second direction of movement. It is essential to the invention that the stationary base element (2) and the second positioning element (4) each have a printed circuit board (5), and the first positioning element (3) is a metal support element (6) and is disposed between the base element (2) and the second positioning element (4).

Description

description

Two-axis positioning device

The invention relates to a two-axis positioning device according to

Claim 1.

From US 2018/0241325 A1 is a generic

Two-axis positioning device with a stationary base element and two positioning elements which can be adjusted in different directions (X and Y directions) relative to the base element are known, the two-axis positioning device having two electromagnetic linear motors for driving the respective positioning element, one

Includes a motion controller and a driver device. The

The base element and the two positioning elements are here

arranged stacked on top of one another, and the positioning element, which is arranged between the base element and the other positioning element, is designed as a printed circuit board (PCB).

On or on the circuit board, in addition to the motion controller and the driver device, also on both sides, i.e. on their top and bottom, the coil elements of the electromagnetic linear motors and

Arranged linear guide devices, two linear guides arranged parallel to one another being provided for both the adjustment in the X direction and in the Y direction.

[0004] A disadvantage of the one known from US 2018/0241325 A1

Two-axis positioning devices are those of conventional ones

Circuit boards with a carrier material made of glass fiber mats (FR-4) impregnated with epoxy resin, the usual low manufacturing tolerances and their low stiffness with common circuit board thicknesses. The

small manufacturing tolerances, which primarily result from the

Manufacturing process related to the used

Materials result, in particular lead to a poor flatness of the circuit board, so that a highly precise and defined alignment of the linear guide devices or the Alignment of the two linear guides per direction of adjustment

is difficult to each other. An imprecise alignment of the two linear guides responsible for realizing an adjustment direction can lead to undesired forces being introduced into the circuit board or into the linear guides during adjustment or positioning, whereby forces introduced into the circuit board can lead to deformation of the same, which is due to the small Rigidity of the circuit board is further promoted, while forces introduced into the linear guides can lead to increased friction. Deformations of the circuit board can have a mechanical negative effect on the adjustment or

Affect positioning accuracy of the two-axis positioning device. In addition, deformations of the circuit board also have a negative effect on measuring or measuring devices arranged on it or integrated therein

Sensor systems, which can lead to measurement inaccuracies or errors.

However, deformations of the circuit board can also result from the forces acting between the magnets and the coils of the electromagnetic linear motors to implement a drive, since the forces generated do not point exclusively in the respective drive direction.

Another disadvantage of the two-axis positioning device according to US 2018/0241325 A1 is the effort required to attach the individual components to the circuit board and in particular the

Linear guide devices. As a rule, press-in sleeves that have an internal thread that are subsequently inserted into the circuit board must be used here. Since the press-fit sleeves normally have a collar with which they are supported on the surface of the circuit board, the press-fit sleeves are above the surface of the

PCB addition what the total height of the

Two-axis positioning device enlarged.

Another disadvantage of the two-axis positioning device known from US 2018/0241325 A1 arises from the fact that the generated by the coils of the electromagnetic drive Electromagnetic fields can penetrate the circuit board practically unhindered and there can influence currents in conductor tracks that are not used to supply the coils electrically, for example currents from sensor components, which can also result in measurement inaccuracies or errors.

[0008] The invention is therefore based on the object of an improved in terms of accuracy and manufacturing costs

Specify two-axis positioning device.

[0009] This object is achieved by a two-axis positioning device with the features of claim 1.

To this end, the stationary base element and the second include

Positioning element in each case a preferably identically designed circuit board, the first positioning element being a metallic one

Carrying element is executed and is arranged between the base element and the second positioning element.

Due to the metallic design of the carrier element, this can be highly precise and in compliance with specified tolerances

in particular extremely flat, for example by a lapping treatment of its surfaces, so that a correspondingly precise arrangement or alignment of the bearing or

Guide devices is enabled. Sensor devices, in particular optical sensor devices, can also be arranged with high precision on such a flat surface.

In addition, the metallic design allows between the

Base element and the second positioning element arranged first positioning element a simple processing and in particular the simple provision of very precisely placed holes or

Threaded bores through which the elements to be arranged on the first positioning element can be fastened easily and at the same time mechanically stable. Due to the high rigidity of the metallic carrier element, it does not tend to become too thick, even if it is thin

Deformations that adversely affect the accuracy of the

Two-axis positioning device can affect. Low thicknesses of the metallic carrier element or the first positioning element are advantageous to the weight for a high

To reduce adjusting movement dynamics as much as possible, the thickness of the metallic carrier element can be made much thinner than a circuit board with the same rigidity.

In contrast, both the base element and the second positioning element comprise a circuit board on which preferably all elements or components of the two-axis positioning device to be supplied with electrical power are arranged or integrated so that the first positioning element does not require any power supply. It is advantageous if at least one motor driver is integrated in each of the two circuit boards. In addition, in the circuit boards

Communication modules (such as a WLAN module) can be integrated. In addition, the circuit boards can have integrated receiving devices for sensor elements. Furthermore, the circuit boards preferably have electrical insulation and electrical insulation

Through contacts on. Particularly preferably, all electrical connections (wiring) between the components or parts of the circuit boards are also integrated therein. The

Circuit boards can also be used for cooling surfaces

Have heat removal. In a preferred embodiment, the circuit boards of the base element and the second positioning element are connected to a metallic carrier plate.

It can be advantageous that at least one of the two drives is designed as an electromagnetic drive comprising at least one coil element and at least one magnet arrangement, and here the magnet arrangement preferably corresponds to a Halbach array. Such a drive can generate high drive forces even with a very flat structure and at the same time very precisely

Carry out adjustment movements. The Halbach array arrangement of the magnets ensures a one-sided, strong magnetic field on the side facing the corresponding coil element, whereby a return element and the metallic one can be dispensed with Carrier element can consist of a magnetically non-conductive metal. However, the invention is not limited to the use of electromagnetic drives for generating the adjustment movements of the first and second positioning elements. So are too

Electric motors or piezoelectric drives are conceivable for this.

It can be of advantage here that on the metallic

Carrier element on the top and bottom each one

Magnet arrangement is located, and the respective magnet arrangement with an oppositely arranged coil element

cooperates. It can be of particular advantage here that the coil element is integrated into the circuit board. Due to the comparatively high weight, an attachment of the

Magnet arrangements on the metallic carrier element are advantageous, while the integration of the coil elements in the circuit boards results in an overall very flat structure

Two-axis positioning device leads. In addition, the coil elements can be integrated into the circuit boards during the manufacture of the circuit boards, so that the assembly of the

Zweiachspositioniervorrichtung is made much easier because fewer parts have to be assembled.

It can be advantageous that the circuit board of the base element is electrically connected to the circuit board of the second positioning element via a flexible connecting element. About this flexible

Connecting element, a power supply for the circuit board of the second positioning element can be implemented via the circuit board of the base element, and it is also used to forward electrical signals, for example for position control. The flexible one

The connecting element allows the same to be carried along smoothly during adjustment movements of the two-axis positioning device, whereby, due to its high flexibility, it offers only an extremely low resistance to corresponding adjustment movements. In addition, advantages and expediencies of the invention result from the following description of exemplary embodiments and aspects with reference to the figures. Of these show:

Fig. 1: Perspective view of an inventive

Two-axis positioning device

Fig. 2: Exploded view of the two-axis positioning device

according to FIG. 1

3: side view of the two-axis positioning device according to FIGS. 1 and 2

4: Representation of details of the two-axis positioning device according to FIGS. 1 to 3 in perspective view

Fig. 5: Representation of details of the two-axis positioning device according to Figs. 1 to 3 in perspective view

6A and 6B: Different perspective views of the

metallic carrier element of the two-axis positioning device according to Figs. 1 to 3

According to FIG. 1, the inventive

Two-axis positioning device 1 has a three-layer or three-layer structure with a base element 2 which is at the bottom in FIG. 1 and which comprises a metallic carrier plate 22 and a printed circuit board 5 arranged thereon or connected thereto. The material of the circuit board 5 is a composite material

Epoxy resin and fiberglass fabric (FR-4). The circuit board 5 has two connector elements 200 for making electrical contact with the

Two-axis positioning device. These are partially embedded in the circuit board 5. One of the plug elements 200 is used to supply current or power to the one used here

electromagnetic drives of the two-axis positioning device, while the other of the two connector elements 200 serves as an interface (e.g. via USB, CAN, RS232, Ethernet or Ethercat) for the

Commanding of adjusting movements or position specifications of the two-axis positioning device functions. Completely embedded in the printed circuit board 5 of the base element 2 cannot be seen in FIG. 1 Coil elements. A motor driver integrated in the printed circuit board 5 of the base element 2 cannot be seen either.

The base element 2 located below is followed by the first positioning element 3 in the form of a metallic one as a middle layer or layer

Support element 6 made of aluminum. Both on the top of the metallic carrier element 6 and on its underside, which faces the printed circuit board 5 of the base element 2, a magnet arrangement (not shown in FIG. 1) is arranged, which in each case corresponds to a Halbach array.

The top layer or ply of those shown in FIG

The two-axis positioning device forms the second positioning element 4, which is constructed similarly to the base element 2 and, in addition to the printed circuit board 5, also comprises a metallic carrier plate 42 which is connected to the printed circuit board 5. One cannot be recognized in the

Printed circuit board 5 of the second positioning element 4 integrated

Motor driver. Both the carrier plate 22 of the base element 2 and the carrier plate 42 of the second positioning element 4 primarily serve to connect the two-axis positioning device to or with higher-level structures, such as a stationary base and an object to be positioned opposite the base. Corresponding fastening or connecting devices, such as threaded bores, are in a simple manner in the metallic carrier plates

collectable. Furthermore, the metallic carrier plates 22 and 42 serve to increase the mechanical stability of the base element 2 and the second positioning element 4. possible to make the circuit boards 5 extremely thin.

However, there are also designs conceivable in which on the

Carrier plate 22 of the base element 2 and the carrier plate 42 of the second positioning element 4 is dispensed with and the circuit boards 5 themselves have means with which a connection of the

Two-axis positioning device is possible on higher-level structures, for example by embedded or embedded in the circuit boards.

pressed-in threaded elements. About such reception facilities can also be used for moving storage of the

Positioning elements 3 and 4 can be arranged on the circuit boards 5. Such receiving devices can also serve to receive or attach sensor elements to the circuit boards. In addition, the thickness of the printed circuit boards 5 can be varied or adapted and correspondingly thick printed circuit board structures can be used which themselves already have the mechanical stability required for the specific application.

To establish an electrical connection between the circuit board 5 of the

To realize base element 2 and the circuit board 5 of the second positioning element 4, whereby on the one hand the current or

Power supply to the embedded in the circuit boards 5

Coil elements as well as the additional components or parts integrated therein such as motor drivers, sensor elements,

Communication modules, etc., and on the other hand the forwarding of electrical signals, for instance for commanding positioning movements, is flexible and electrically conductive

Connecting element 9 is provided, the flexibility of which is sufficient to oppose the movements of the two positioning elements 3 and 4 only with a very low resistance and that the same can be carried along smoothly during adjustment movements

Two-axis positioning device allowed.

In order to realize a precisely guided linear movement along the two directions of movement arranged perpendicular to one another, the two-axis positioning device has a total of four

Linear guide devices 100, two of which are arranged in a parallel and spaced arrangement between the base element 2 and the first positioning element 3, and of which the remaining two are arranged in a parallel and spaced arrangement between the first positioning element 3 and the second

Positioning element 4 are arranged. It is also conceivable to provide only one linear guide device for each of the two directions of movement or adjustment that are perpendicular to one another. [0030] FIG. 2 corresponds to an exploded view of FIG

Two-axis positioning device according to FIG. 1. In comparison to the illustration according to FIG. 1, the linear guide devices 100 can be seen more clearly. In addition, FIG. 2 cannot do that in FIG

recognizable magnet arrangement 8 in the form of a Halbach array, which is used in the electromagnetic drive for the second positioning element 4.

FIG. 3 corresponds to a side view of the two-axis positioning device 1 according to FIGS. 1 and 2. Fig. 3 can in particular additionally between the metallic carrier element 6 and the second

Positioning element 4 arranged measuring device 300 comprising a scale 302 arranged on the metallic carrier element 6 and a sensor 304 interacting with the scale 302, which is arranged opposite it on the second positioning element 4, the measuring device 300 detecting or measuring the position of the second positioning element 4 relative to the first positioning element 3 and from the

Position detection derived from the position control of the second positioning element 4 is used. An analog measuring device 300, which cannot be removed from FIG. 3, is on the underside of the metallic

Arranged carrier element 6, which is used in an analogous manner to detect or measure the position of the metallic carrier element 6 relative to the base element 2 and thus its position control.

In Fig. 4 only individual exposed or cut out

Elements of the two-axis positioning device according to FIGS. 1 to 3 shown. These are the respectively interacting coil elements 7 and magnet arrangements 8 of the two

electromagnetic drives. Since the coil elements 7 in the two-axis positioning device according to FIGS. 1 to 3 are completely embedded in the corresponding circuit board 5 and would therefore not be recognizable in the normal representation, they are shown cut out of the circuit board in FIG. The Magnet assemblies 8 are each fastened to the metallic carrier element 6, the coil elements 7 and the magnet assemblies 8 being arranged opposite one another in pairs.

Each coil element 7 comprises three nested one inside the other

arranged separate conductor tracks, so that a three-phase

Control of the coil elements 7 is enabled. The

Magnet assemblies 8 each comprise a Halbach array and have a longitudinal direction that corresponds to the

The direction of longitudinal extension of the associated coil element 7 coincides.

In FIG. 4, the total of four linear guide devices 100 can also be clearly seen, each of which is aligned in pairs parallel to one another and ensures the highly precise guidance of the associated positioning element in the respective guide direction.

Fig. 5 also contains only individual exposed or

cut-out elements of the two-axis positioning device according to FIGS. 1 to 3. In particular, FIG. 5 shows the base element 2 and the one integrated or embedded in its circuit board 5

Coil element 7. Furthermore, FIG. 5 shows the magnet arrangement 8 assigned to the coil element 7 in the form of a Halbach array, which together form the electromagnetic linear drive for the first positioning element 3. The magnet arrangement 8 is arranged or fastened to the first positioning element 3 (not shown) in the form of the metallic carrier element 6. Parallel to the

Direction of longitudinal extension of the coil element 7 or the

Magnet assembly 8, which the drive direction of the

electromagnetic drive are the two

Linear guide devices 100 arranged. These are connected on the one hand to the printed circuit board 5 of the base element 3 and on the other hand to the metallic carrier element 6 of the first positioning element 3.

Fig. 6 shows the metallic in the two representations 6A and 6B

Carrier element 6 of the two-axis positioning device according to FIGS. 1 to 3 in different perspective views. FIG. 6A shows the upper side of the carrier element, while FIG. 6B shows the underside of the metallic carrier element. On the top of the metallic carrier element according to FIG. 6A are in

corresponding recesses, two linear guide devices 100 are arranged in parallel alignment to one another, and the magnet arrangement 8 is located between these in an analogous alignment. In addition, a measuring element 302 of a corresponding measuring device, which has a scale 306 and a reference track 308, is arranged on the upper side of the metallic carrier element.

The underside of the metallic carrier element is according to FIG. 6B

Equipped identically to its top and carries two in addition

Linear guide devices 100, the magnet arrangement 8 and a measuring element 302 of a measuring device comprising a scale 306 and a reference track 308. The alignment of the

Linear guide devices 100 and the magnet arrangement 8 on the underside of the metallic carrier element is identical and is perpendicular to the alignment of the linear guide devices 100 and the magnet arrangement 8, which are arranged on the upper side of the metallic carrier element.

It is conceivable to use two or more of the above-described

To combine two-axis positioning devices. It is also conceivable to use one described above

Two-axis positioning device with a further positioning device, for example a further linear positioning device or a

Rotation positioning device or a tilt positioning device to combine.

List of reference symbols

1 two-axis positioning device

2 basic element

3 first positioning element

4 second positioning element

5 circuit board metallic carrier element

Coil element

Magnet arrangement

flexible connector

Carrier plate

Linear guide device

Connector element

Measuring device

Measuring element (of measuring device 300) Sensor (of measuring device 300) Scale (of measuring element 302) Referencing track (of measuring element 302)

Claims

Expectations

Claim 1. Zweiachspositioniervorrichtung (1) comprising a base element (2), a first, relative to the base element (2) movably mounted along a first direction positioning element (3), a second, opposite the first positioning element (3) along a second and from the first direction deviating movably mounted positioning element (4), a first drive for adjusting the first positioning element (3) along the first direction of movement, a second drive for adjusting the second positioning element (4) along the second direction of movement, characterized in that the stationary base element (2) and the second positioning element (4) have a printed circuit board (5), and the first positioning element (3) is designed as a metallic carrier element (6) and between the

Base element (2) and the second positioning element (4) is arranged.

Claim 2. two-axis positioning device according to claim 1, characterized

characterized in that at least one of the two drives is designed as an electromagnetic drive comprising at least one coil element (7) and at least one magnet arrangement (8).

Claim 3. two-axis positioning device according to claim 2, characterized

characterized in that at least one magnet arrangement (8) is arranged on the metallic carrier element (6), and the

Magnet arrangement with one provided opposite

Coil element (7) cooperates.

Claim 4. two-axis positioning device according to claim 2 or 3, characterized in that the coil element (7) is integrated in a printed circuit board (5).

Claim 5. two-axis positioning device according to one of claims 2 to 4, characterized in that the magnet arrangement (8) one

Halbach array corresponds. Claim 6. Two-axis positioning device according to one of the preceding claims, characterized in that a communication module is integrated in at least one of the circuit boards (5).

Claim 7. Two-axis positioning device according to one of the preceding claims, characterized in that at least one of the circuit boards (5) has receiving devices for a bearing or for a sensor element.

Claim 8. Two-axis positioning device according to one of the preceding claims, characterized in that the circuit board (5) of the base element (2) is electrically connected to the circuit board (5) of the second positioning element (4) via a flexible connecting element (9).

Claim 9. Two-axis positioning device according to one of the preceding claims, characterized in that the circuit board (5) of the base element (2) is identical to the circuit board (5) of the second

Positioning element (4) is executed.

Claim 10. Computer program product which is designed to be a

to generate digital imaging of the two-axis positioning device according to one of the preceding claims.