JPH037882Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a sample moving device in an electron microscope or the like.

[Prior art] As a sample moving device for a conventional electron microscope, three bushes are fixed to the upper surface of the upper yoke of the objective lens and are placed at equal intervals around the optical axis, and the sample is mounted on these bushes. A structure in which a sample moving stage is placed under pressure with a spring, and the sample is moved horizontally by operating two sets of drive rods that are in contact with the sides of the sample moving stage. is widely used.

[Problems to be solved by the invention] In order to move the sample moving stage smoothly in such an apparatus, the top surface of the bushing is coated with Teflon (registered trademark), and the Teflon is coated with some amount of grease, etc. It is used in a coated state.

However, if the pressure in the sample chamber is high vacuum, for example, 10 ^-8 Torr or higher, there is not much problem with using grease, but the pressure in the sample chamber is
If an ultra-high vacuum of 10 ^-8 Torr or less is required, grease etc. cannot be used, so the movement of the sample moving stage will be impaired. Furthermore, in order to obtain an ultra-high vacuum, each member such as the sample chamber wall, sample moving stage, and objective lens yoke must be heated to a high temperature of several hundred degrees or more to release the gas occluded in each member. There must be. Therefore, since Teflon is also heated at the same time, there is a risk that the surface of Teflon will be damaged and the movement of the sample moving stage will become even worse.

In consideration of the above-mentioned problems, the present invention is a sample moving device for an electron microscope that can move smoothly even when heat bakeout is applied to obtain an ultra-high vacuum. is intended to provide.

[Means for Solving the Problems] The configuration of the present invention is such that when a sample moving table on which a sample is mounted is movably placed on a base, a retainer fixed to the base is placed between the two. At least three ball bearings were installed, each consisting of several small balls rotatably placed in an annular V-shaped groove and a large ball supported by these small balls and in contact with the sample moving table. It is characterized by this.

[Example] Fig. 1 is a longitudinal sectional view showing an example of the present invention used in a sample device of the type in which a sample is inserted from the optical axis direction. It consists of a pole piece 5 in which the piece 2 and the lower pole piece 3 are integrated by a non-magnetic spacer 4, a lens yoke 6, and an excitation coil 7. 8a to 8c (8c is not shown) are three ball bearings fixed to the upper part of the lens yoke 6 at equal intervals around the optical axis Z, and each of these bearings is shown in FIGS. 2 and 3. As shown in the enlarged view, a cylindrical retainer 10 has an annular guide groove 9 formed at the bottom.
It is composed of, for example, eight small balls 11a to 11h arranged in the guide groove 9 of the retainer so as to be rotatable and in contact with each other, and a large ball 12 supported by each of the small balls. . The guide groove 9 formed in the retainer has a V-shaped cross section, and the small balls 11a to 11h are connected to this groove.
By minimizing the contact area with the ball, the rolling resistance of the small ball is reduced.

Reference numeral 13 denotes an annular sample moving table disposed on the three ball bearings 8a to 8c, and a sample cylinder 16 holding a sample 15 via a mounting table 14 is removably attached to the center of the table. Moreover, the sample moving table 13
Mirror-finished bushes 17a to 17c are embedded in the contact portions with the ball bearings 8a to 8c, respectively. This bush 17a to 17
c and the ball bearings 8a to 8c are made of a bearing material such as cemented carbide.

As the sample moving stage 13 moves horizontally, the large ball 12 rotates, and the small balls 11a to 11h rotate accordingly.
The sample moving stage can be moved smoothly. At this time, since the large ball 12 is supported by a large number of small balls 11a to 11h, there is point contact.
In addition, since the small ball is also supported by the annular guide groove 9 with a V-shaped cross section, point contact is also achieved, and as a result, the rolling resistance of the ball bearing can be extremely reduced, and the sample stage can be supported. The position of the large ball can be maintained at a constant position suitable for

FIG. 4 is a longitudinal sectional view showing another embodiment of the present invention, in which the upper surface of each retainer 10 is
Rather than placing it horizontally as shown in the figure, it is fixed at a certain angle (for example, 15 degrees).
At this time, the direction of inclination of each ball bearing is such that the upper surface of each retainer 10 faces the optical axis Z, respectively.

By doing this, the contact resistance of the several small balls 11a to 11h with respect to the retainer 10 is weakened, so that the large balls 11 due to the movement of the sample moving stage 13 are
The rotation of the small balls 11a to 11h following the rotation of is smoother, and the movement of the sample moving stage 13 is even smoother than that of the structure shown in FIG.

In the above explanation, we have described the case where the sample is inserted into a sample device of the type in which the sample is inserted from the optical axis direction, but the present invention is not limited to this. Needless to say, the present invention can be similarly applied to a sample device in which the sample is placed on the optical axis Z by mounting a sample holder on the side of the stand. or,
It can also be implemented in a sample moving device of a scanning electron microscope. In this case, the ball bearing will be fixed to a base such as a stage fixed to the bottom of the sample chamber or the wall of the sample chamber.

[Effects of the invention] As described above, according to the invention, when the sample moving table on which the sample is mounted is movably placed on the base, the retainer fixed to the base is placed between the two. Install at least three ball bearings each consisting of several small balls rotatably placed in an annular V-shaped groove and a large ball supported by these small balls and in contact with the sample moving table. By doing this, the contact between the large ball and the small ball, and the contact between the small ball and the V-shaped guide groove becomes point contact, respectively, and the rolling resistance of the ball bearing can be extremely reduced. Since it can be maintained at a fixed position suitable for support, even when heat baking is applied to obtain an ultra-high vacuum, the sample surface can be maintained smoothly and without any hindrance. The sample stage can be moved without causing shaking or the like.

Furthermore, since the rolling resistance of the ball bearing is extremely small, the pressing force applied between the sample stage and the ball bearing can be increased compared to the conventional method, and vibration resistance can also be improved.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing one embodiment of the present invention, Figs. 2 and 3 are longitudinal sectional views and plan sectional views of a ball bearing used in the present invention, and Fig. 4 is a longitudinal sectional view showing an embodiment of the present invention. FIG. 3 is a longitudinal cross-sectional view showing an example. 1: Objective lens, 5: Pole piece, 6: Lens yoke, 7: Excitation coil, 8a to 8c: Ball bearing, 9: Guide groove, 10: Retainer, 11a
~11h: Small ball, 12: Large ball, 13:
Sample moving table, 14: Mounting table, 15: Sample, 16:
Sample cylinders, 17a to 17c: bushes.

Claims (1)

[Claims for Utility Model Registration] (1) When a sample moving table on which a sample is attached is movably placed on the base, an annular V-shaped groove in a retainer fixed to the base between the two. At least three ball bearings each consisting of several small balls rotatably placed on the sample moving table and a large ball supported by these small balls and in contact with the sample moving stage are installed. Sample moving device for electron microscopes, etc. (2) In the electron microscope or the like as set forth in claim 1 of the utility model registration claim, wherein the ball bearings are fixed to the base at an angle so that the upper surfaces of the respective retainers face in the direction of the optical axis. Sample moving device.