A micromanipulator for the displacement of a sample carrier according to different degrees of freedom by means of displacement members (26) fixed to elastic bellows (21.sub.1, 21.sub.2, 21.sub.3, 23), which participate in the transmission of movement through a wall (37). At least one rotary movement of the sample carrier is transmitted through the said wall by means of a transmission pin (11.sub.1, 11.sub.2) movable in translation, which is fixed to a said bellows (21.sub.1, 21.sub.2). At least one translatory movement of the sample carrier can also be transmitted by at least one respective transmission pin (11.sub.3) movable in translation. The transmission pins operate in the translation mode parallel to a single direction. The sample carrier can perform on the one hand a translatory displacement and on the other hand a rotary displacement according to a rotation in its plane and according to a rotation by inclination of the said plane.

BACKGROUND OF THE INVENTION 
The invention relates to a micromanipulator for the displacement of a 
sample carrier according to different degrees of freedom by means of 
displacement members mounted on elastic bellows, which participate in the 
transmission of the movements through a wall. 
Such a manipulator can be used in a vacuum or in an ultrahigh vacuum or in 
controlled atmospheres. 
A micromanipulator of this kind is described in U.S. Pat. No. 4,587,431. It 
permits of ensuring in an ultrahigh vacuum the positioning of samples 
before a beam. The displacement can be effected according to three 
orthogonal translatory movements and according to two rotations: the 
rotation of the sample itself with respect to the axis perpendicular to 
its plane and a rotation of inclination of this plane with respect to the 
beam. In order to obtain the transmission of the commands between the zone 
at atmospheric pressure and the zone in an ultrahigh vacuum, elastic 
bellows are used. For the transmission of the translatory movements of the 
sample, the bellows concerned are moved by transmission means, which 
perform a translatory displacement. For the transmission of the rotary 
movements of the sample, the bellows concerned are moved by rotation 
means, which in the zone in an ultrahigh vacuum are transmitted by means 
of a so-called "pig-tail device". 
However, such a micromanipulator is voluminous. Moreover, the bellows 
transmitting the rotary movements operate in the torsional mode, which can 
be detrimental to their operation. In fact, such repeated actions render 
the bellows brittle, which can then present microleaks or larger leaks, 
which results in that the lifetime of these bellows is limited. 
The problem to be solved by the invention is to provide a micromanipulator 
which is as compact as possible, which offers several degrees of freedom 
in translation and/or in rotation with high amplitudes and a high 
precision and which transmits the initial commands while avoiding to exert 
torsional forces on the bellows. It must ensure a very stable position of 
the sample and it must be readily controllable from the outside in order 
to permit a programmable operation. 
SUMMARY OF THE INVENTION 
The solution of this problem consists in that at least one rotary movement 
of the sample carrier is transmitted through the said wall by means of a 
transmission pin, movable in translation, which is fixed to a said 
bellows. The transmission pin is connected to a mounting and displacement 
means which converts the translation of the transmission pin into rotation 
of the carrier. 
The rotation of the sample carrier can take place about an axis 
perpendicular to the plane of the surface of the sample carrier intended 
to receive the sample. The rotation can also be effected in that this 
plane is inclined with respect to an initial position. 
The mounting and displacement means can also cause the sample carrier to be 
subjected to translatory displacements either in the plane or 
perpendicular to the said surface of the sample carrier. 
The micromanipulator is intended in the first place to position a sample in 
an ultrahigh vacuum before an analysis apparatus, such as an analyser by 
spectroscopy of the photoelectrons originating from X-rays (X-ray 
photoelectron spectroscopy XPS). However, it is possible to use it with 
other types of analysis apparatus or for other environments, for example 
protected atmospheres. It permits of working with samples of large 
dimensions (i.e. of large mass for this type of application) due to the 
large displacement amplitudes permitted by it. It is possible to position 
a point situated at the surface of the sample with respect to an analysis 
beam and to cause the incidence angle to vary at this point. A rotation of 
the sample itself can also be obtained.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 is a strongly simplified schematic diagram of a micromanipulator 10, 
given by way of example, having 4 degrees of freedom. Under the action of 
transmission pins 11.sub.1, 11.sub.2, 11.sub.3, the displacement members 
will carry out a translation X, a rotation a and a rotation b of the 
sample carrier 12 with respect to an incident analysis beam 13. Through 
translation of bellows 23 by a screw/nut mechanism 87, the carrier 12 also 
performs a translation Z. A sample 14 is placed on the surface 15 of the 
sample carrier 12. The sample carrier can be subjected to a rotation a 
about an axis perpendicular to the surface 15. Likewise, the sample 
carrier can be subjected to a rotation b, which inclines the surface 15 
with respect to the incident beam 13. The two rotations are effected about 
the impact point A of the beam 13 when the point A is located at the 
crossing of the two axes of rotation. 
FIG. 2 shows a schematic diagram of a first embodiment of a 
micromanipulator according to the invention, which permits of ensuring the 
4 degrees of freedom indicated in FIG. 1. The transmission pins 11.sub.1, 
11.sub.2, 11.sub.3 transmit translatory movements while causing three 
elastic bellows 21.sub.1, 21.sub.2, 21.sub.3 to participate. These bellows 
are intended to ensure vacuum or gas tightness between two zones 1, 2 
isolated from each other. 
In the present case, an ultrahigh vacuum apparatus is concerned, the zone 1 
being placed in the ambient atmosphere and the zone 2 being placed in an 
ultrahigh vacuum. The separation is effected by the bellows 21.sub.1, 
21.sub.2, 21.sub.3 and by a clamp 22 fixed on a wall 37. Another bellows 
23, whose function will be described hereinafter, can also participate in 
the isolation of the two zones. 
The two rotary movements a and b are ensured by the pins 11.sub.1 and 
11.sub.2 and the translatory movement is ensured by the pin 11.sub.3. The 
pins are translated by translation means 24 and they act upon the sample 
carrier by means of a mounting and displacement means 26. 
In order to carry out the two rotations, the pins 11.sub.1 and 11.sub.2 act 
upon first and second gear trains which include toothed racks 25.sub.1 and 
25.sub.2, respectively. Each toothed rack 25.sub.1, 25.sub.2 takes along 
by means of a shaft 27.sub.1, 27.sub.2 cylindrical pinions 28.sub.1, 
28.sub.2, 29.sub.1, 29.sub.2 and a conical carrier pinion 30.sub.1, 
30.sub.2 coupled to carrier 31. Thus, in order to transform the 
translations of the transmission pins into a rotation of the sample 
carrier, the mounting and displacement means includes two gear trains, 
each comprising a toothed rack coupled to a cylindrical pinion provided 
with a shaft, which takes along at least one carrier pinion, which sets 
the sample carrier into rotation. 
The two conical pinions 30.sub.1, 30.sub.2 can rotate either in the same 
sense or in opposite senses and can act simultaneously upon the carrier 
31. 
This double possibility is permitted by subjecting the transmission pins 
11.sub.1, 11.sub.2 to translations either in the same direction or in 
opposite directions. 
Thus, the transmission pins can be displaced simultaneously in opposite 
directions so that the pinions meshed with the sample carrier rotate in 
different directions of rotation, thus producing a rotation of the sample 
carrier about an axis perpendicular to its plane. 
Likewise, the transmission pins can be displaced simultaneously in the same 
direction so that the pinions meshed with the sample carrier rotate in the 
same direction of rotation, thus producing a rotation of the sample 
carrier while inclining its plane with respect to an initial position. The 
senses of rotation of the pinions are described with respect to a given 
direction. 
The translations of the transmission pins are imposed by translation means 
24. In order to cause the translation means 11.sub.1, 11.sub.2 to be 
displaced in opposite senses, the translation means 24 comprise a 
double-grooved screw 32 having an inverted pitch. The pins 11.sub.1, 
11.sub.2 have at their end each a bolt 33.sub.1, 33.sub.2, which is 
displaced in one and in the other groove, respectively. Thus, by the 
rotation in one or in the other direction of the screw 32, it is possible 
to set the sample carrier into rotation in one or in the other direction. 
The screw 32 is set into rotation by the pinions 34.sub.2, 35.sub.2 
controlled in rotation by the motor 36.sub.2. 
In order to obtain the displacement of the pins 11.sub.1 and 11.sub.2 in 
the same direction, it is sufficient to translate the screw 32 by means of 
the screw 87 and the pinions 35.sub.1 and 34.sub.1. A motor 36.sub.1 can 
set the pinion 34.sub.1 into rotation. 
Thus, in order to produce two rotations of the sample carrier by means of 
rotational inputs, the micromanipulator comprises two elastic bellows, of 
which each transmission pin is set into translation by translation means 
comprising for the inverted translation a first bolt integral with the end 
of the first pin, which is displaced in one of the grooves of a 
double-grooved screw having an inverted pitch, and a second bolt integral 
with the end of the second pin, which is displaced in the other groove, 
the screw being set into rotation by a rotation means, while for the 
translation of the pins in the same sense there is provided a screw/nut 
system integral with the screw 32 and displacing it axially. The amplitude 
of the displacement of the pins is determined by the ends of the two 
grooves. 
Thus, not a single interference occurs between the two rotations a and b. 
The translatory movement of the surface of the sample carrier in its plane 
in the direction X is obtained by means of the transmission pin 11.sub.3. 
It displaces a toothed rack 40, which acts upon a cylindrical pinion 41 
having the same axis as a cylindrical pinion 42, which acts upon a toothed 
rack 43. 
Thus, in order to transform the translations of the transmission pins into 
translations of the sample carrier in a different manner, the displacement 
members comprise for an arbitrary translation a toothed rack coupled to a 
cylindrical pinion coaxial with another cylindrical pinion, which takes 
along another toothed rack, which causes a translatory displacement of the 
sample carrier. 
It is possible to double the number of elements for translating the sample 
carrier in two different directions X and Y. The transmission pins 
ensuring the translations of the sample carrier are displaced in 
translation parallel to the one direction. 
The transmission pin 11.sub.3 can be caused to perform a translatory 
displacement by a rotation means, such as motor 36.sub.3. The rotation is 
transformed into axial transmission of pin 11.sub.3 by a rotation means of 
a mechanism comprising a movable screw/nut system 88. 
It is possible that the sample carrier is subjected either to rotary 
displacements or to translatory displacements. 
It is also possible to combine these two types of displacement; for this 
purpose, the shafts 27.sub.1, 27.sub.2 are grooved so that the pinions 
28.sub.1, 28.sub.2, 29.sub.1, 29.sub.2, 30.sub.1, 30.sub.2 and the 
platform 31 can slide along these shafts when the toothed rack 40 imposes 
a translatory movement on the sample carrier. 
The displacement members can cause the sample carrier to be subjected to 
rotary displacements and to translatory displacements, the shaft 
transferring the rotation to the sample carrier being grooved to ensure 
that the pinions taking along this carrier slide longitudinally along its 
periphery. 
According to the schematic diagram shown in FIG. 1, a micromanipulator is 
obtained, for which the regulations of the rotations a and b are 
independent, that is to say that a slight modification of one of the 
regulations does not influence the other. 
According to FIG. 3, it is possible to obtain a simplified embodiment, in 
which this characteristic is not fully satisfied. In this case, a 
modification of one of the regulations of rotation necessitates to 
readjust the other rotation regulation. FIG. 3 exhibits all the 
characteristics of FIG. 2 except the following points solely relating to 
the two rotations. 
Translation means now no longer comprise the screw 32. The pins 11.sub.1 
and 11.sub.2 are individually controlled. For this purpose, they each have 
a mechanism comprising a movable screw/nut system 50.sub.1, 50.sub.2 to 
operate by means of initial rotational inputs from rotation means such as 
motors 36.sub.1, 36.sub.2, 36.sub.3. 
The displacement members no longer comprise the conical pinion 30.sub.1 
cooperating with the pinion 30.sub.2. In FIG. 3, the pinion 30.sub.1 is 
replaced by a straight pinion 51, which is taken along by the pinions 
29.sub.1, 28.sub.1, the shaft 27.sub.1 and the toothed rack 25.sub.1. 
In order to permit a displacement in the direction Z perpendicular (when it 
is not inclined) to the surface 15 (FIG. 1) of the sample carrier, it is 
possible to place three bellows 21.sub.1, 21.sub.2, 21.sub.3 on a bellows 
23, which is displaced also by a translatory movement in the same 
direction. Thus, the assembly constituted by the mounting and displacement 
means 26, the bellows 21.sub.1, 21.sub.2, 21.sub.3, the transmission pins 
11.sub.1, 11.sub.2, 11.sub.3 and the translation means 24 may be displaced 
as a whole in the direction Z. 
The initial commands, which actuate the transmission pins 11.sub.1, 
11.sub.2, 11.sub.3, can be translation commands. They can be produced by 
actuators. 
Preferably, the translation means 24 are intended to produce a translatory 
movement of the transmission pins 11.sub.1, 11.sub.2, 11.sub.3 by means of 
initial rotational inputs, as has been described above. 
In this case, the rotational inputs can be produced by motors. This permits 
a programming of the operation of the micromanipulator. 
Such a micromanipulator is adapted to receive samples having a diameter of 
50.8 mm with a rotation a in the plane varying from 0.degree. to 
360.degree. with an accuracy of .+-.0.1.degree.. The rotation b can be 
effected between -30.degree. and 60.degree. with an accuracy of 
.+-.0.1.degree.. The translation X reaches .+-.12.5 mm with an accuracy of 
.+-.0.02 mm and the translation Z can reach 100 mm with an accuracy of 
.+-.5 .mu.m. It is capable of withstanding temperatures up to about 
150.degree. C. The sample carrier can be electrically insulated by means 
of a ceramic plate fixed to the sample carrier 31. The axes of rotation 
are then defined accordingly.