NL1042960B1

NL1042960B1 - High Dynamic Planar Motion Stage for use in low-temperature environments

Info

Publication number: NL1042960B1
Application number: NL1042960A
Authority: NL
Inventors: Hubertus Leonardus Mathias Marie Janssen Ir
Original assignee: Janssen Prec Engineering; Hubertus Leonardus Mathias Marie Janssen Ir
Priority date: 2018-08-21
Filing date: 2018-08-21
Publication date: 2020-02-27

Abstract

The invention concerns a planar motion stage focussing on X and Y translations with high dynamic performance 5 specially designed to be used in cryogenic environments. In order to be less sensitive for disturbance vibrations from outside a drive concept with high resonance frequencies is required. Due to the introduction of a drive concept in which 10 three translation actuators are able to drive the sample holder in a parallel way. Still making use of piezo actuators and a lever arm, the drives (translation actuators) are situated that their drive stiffness is acting in a parallel mode to the sample holder. 15 20 25 30 1042960

Description

High Dynamic Planar Motion Stage for use in lowtemperature environments

The invention concerns a planar motion stage focussing on X and Y translations with high dynamic performance specially designed to be used in cryogenic environments.

For several physics experiments like research in quantum physics, samples need to be positioned in a low temperature environment close to the absolute zero point. Positioning requirements often need a continuous movement with nanometric resolution in an open-loop configuration or in a closed-loop controlled configuration. In an open-loop configuration it is important that the sample is not sensitive to disturbing outer vibrations. For a closed-loop control it is important that the sample position is closely following the desired control set-point.

Both configurations benefit from a high mechanical resonance frequency between sample and outer frame of the motion stage.

Additional requirements like the need of a non-magnetic positioning stage limit the design solutions to the use of piezo based actuators which are prawn to very limited strokes in cryogenic environments. Due to the low temperature environment, solutions are based on piezo actuators in combination with a lever arm in order to realize reasonable strokes for a single translation. Common solutions for an X,Y positioning stage are based on a configuration where two stages are stacked in series in order to realize both translations.

Due to this common concept, the mechanical resonance frequency will decrease dramatically.

The invention concerns the introduction of a drive concept in which three translation actuators are able to drive the sample holder in a parallel way. Still making use of piezo actuators and a lever arm, the drives (translation actuators) are situated that their drive stiffness is acting in a parallel mode to the sample holder.

The exact nature of this invention, as well as its objectives becomes clear in the accompanying drawings wherein:

Fig.l Is a top view of the invention.

Figure 1 shows a top view of the system, where the base frame 1 is connected via 3 piezo actuators 2 and a lever based drive m e c h an i s m (4,5,6,7,8 ) to the central sample holder 3 in such a way that the sample holder can be manipulated in three degrees of freedom in the horizontal plane, translations in X, Y and rotation about orthogonal Z axis. The sample holder is manipulated by three drive systems completely symmetric and in a parallel way.

The lever based drive mechanism is constructed as a monolithic body by flexure joints 5,6,7,8 without any play. The lever arm 4 is realized by the localization of the joints 5,6 and 7 which take care of an amplification ratio of the piezo actuator 2 stroke. So in fact the stroke of the piezo actuator 2 is increased at the location of the joint 7 and also changed in direction (orthogonal to the piezo actuator stroke).

Three of these lever based drive mechanisms are connected via connection rod 9 to the sample stage such that the sample stage can be manipulated in the X,Y plane. All the flexure joints are designed in such a way that they have considerable stiffness in Z direction creating high stiffness and therefore also high mechanical resonance for out of plane motion.

The connections between piezo actuators 2 and the monolithic body are preloaded by spring 10 in order to avoid any tensile stresses in the piezo material.

Claims

1. The invention relates to a device characterized in that:

A table to be positioned by means of three piezo actuators lying in the same plane as the table is moved relative to a reference frame;

the length of the piezo actuators due to an external voltage or supplied charge can be varied;

the variation in the length (elongation) of the piezo actuators is increased by means of a lifting b o m o r e r b r e n g i n g;

the extension of the piezo actuators has a displacement component that is tangential to the circumscribed circle through the three pivot points between p i e z o - a c t u at o r and the table to be positioned;

the pivot points have a high rigidity perpendicular to the plane defined by the movement;

the hinge points are elastic so that no friction and play is introduced;

the entire module of the table, pivot points, the b o o m o r e r b r e n g i n g and reference frame are manufactured as a monolytic part, with the exception of the separately added piezo actuators.

there is a constant positive pressure applied to the piezo actuators by a biasing spring.