JP3261451B2 - Cantilever for detecting frictional force - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cantilever for detecting a frictional force used for measuring a frictional force or a frictional force distribution in a frictional force microscope (FFM) using an atomic force microscope (AFM). The present invention relates to a cantilever for frictional force detection capable of setting an arbitrary frictional force detection sensitivity, measuring a frictional force distribution with high accuracy, and realizing an invariable contact point of a probe tip portion in contact with a sample.

[0002]

Conventional friction sensing cantilever is typically as shown in FIG. 5, the cantilever body 2 1 attached to the base portion of the FFM as a single leaf spring structure, the tip of the cantilever body 2 1 attach the probe 2 2. In such a conventional cantilever, the sample 20
Since the bending stiffness, which is the dominant factor when measuring the shape and focus curve, and the torsional stiffness, which is the dominant factor when measuring the friction force, cannot be set independently, the focus curve was taken into account. When measuring the frictional force, there is a limit to the magnitude of the frictional force that can be measured.

[0003] Also, if an attempt to improve the detection sensitivity of the frictional force, it is necessary to reduce the torsional rigidity, in this case, as shown in FIG. 6, relative to the direction of arrow X sample 2 0 to the probe 2 2 when moving, causes the tip position of the probe 2 2 is changed by the torsional deformation, it was difficult to accurately frictional force distribution measurement. Furthermore, the torsional deformation, a position pro <br/> over Bed 2 2 contacts the sample 2 0 ends up changing,
It was not always possible to measure under the same conditions.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and the technical problem thereof is that the twisting is basically performed without affecting the bending rigidity of the cantilever body. An object of the present invention is to provide a cantilever for detecting a frictional force, which has improved rigidity and can detect a frictional force in a state hardly affected by torsional deformation.
Further, another technical problem of the present invention is to set an arbitrary frictional force detection sensitivity, measure a frictional force distribution with high accuracy, and realize a constant contact point at a probe tip portion that comes into contact with a sample. To provide a cantilever for a vehicle.

[0005]

According to the present invention, there is provided a cantilever for detecting a frictional force, comprising a plurality of parallel leaf springs which are perpendicular to a surface of a test sample.
The cantilever body is formed by opposing at intervals and by mutually constraining both ends of the leaf springs, and the base end thereof can be fixed to a base attached to a friction force microscope, and the cantilever bodies can be fixed. A block-shaped head is provided at the tip, a probe is provided on the surface of the head facing the sample side, and a circle having a different reflection angle of the laser beam for displacement detection depending on the position of the head on the head.
Shaped by cylindrical or spherical projections or depressions
In which it characterized in that a made reflective surface.

[0006] In the above-mentioned friction force detecting cantilever, a cantilever attached to a base of a friction force microscope is used.
An arbitrary spring constant for vertical displacement
Ru can Rukoto is interposed a plurality of parallel plate springs give.

In the cantilever for detecting a frictional force having the above structure, when the sample moves in a lateral direction relative to the probe, a frictional force acts on the probe, and the probe does not change the angle together with the head due to the frictional force. Displace parallel.
When the head is displaced in the lateral direction and a laser light spot is irradiated on a reflection surface provided on the head, an angle change amount of the reflected laser light is detected as a frictional force signal. By changing the curvature or the like of the reflection surface, the detection sensitivity of the frictional force can be set arbitrarily without changing the rigidity of the cantilever body. Further, with the cantilever body having the above-described structure, it is possible to measure the frictional force distribution with high accuracy and to realize a constant contact point at the tip of the probe that comes into contact with the sample.

[0008]

1 and 2 show a first embodiment of a friction force detecting cantilever according to the present invention. The cantilever for detecting a frictional force of this embodiment comprises a cantilever main body 2 by arranging two parallel leaf springs 3 facing perpendicularly to the surface of the test sample 1 at appropriate intervals. The distal end and the proximal end of the cantilever body 2 are mutually restricted, that is, the proximal end is integrally fixed to the base 7 attached to the FFM, and the distal end of the cantilever body 2 including the leaf spring 3 is fixed. The portions are joined by a block-shaped head 4, and a probe 5 is provided on a surface of the head 4 facing the sample 1. The reflection angle of the laser beam L for displacement detection differs on the head 4 depending on the position. Is provided.

Therefore, as shown in FIG. 2, when the sample 1 moves in the lateral direction relative to the probe 5 in the direction of the arrow X, a frictional force acts on the probe 5, and the probe 5 is moved by the frictional force. It is displaced in parallel with the head 4 without changing the angle. Thereby, the contact state between the probe 5 and the sample 1 irrespective of the magnitude of the frictional force is maintained. Thus, when the head 4 is displaced in the lateral direction,
When a spot of the laser light L emitted from the FFM is irradiated on the reflecting surface 6 provided on the head 4, the light is reflected on the reflecting surface 6 on the head 4, but the spot of the laser light L is moved with the movement of the probe 5. The irradiation position changes, and the angle of the laser beam reflected by the reflection surface 6 changes, and the amount of the change is detected as a frictional force signal by a photodetector (not shown).

In the cantilever for detecting a frictional force shown in FIG. 1, the cantilever body 2 is formed by arranging two parallel leaf springs 3 at an appropriate interval to face each other. The number 3 may be three or more and they may be connected by a block-shaped head 4. Further, the reflection surface 6 in the illustrated embodiment is used.
Is a projection with a partial cylindrical surface shape, but it can be formed by a depression of the same shape, and if it is a reflection surface that varies the reflection angle of the laser beam for displacement detection depending on the position, even if it is a spherical surface ridge Shape. Furthermore, by changing the radius of curvature or the like of the reflection surface 6, the detection sensitivity of the frictional force can be arbitrarily set without changing the rigidity of the cantilever body 2.
In order to improve the sensitivity of the head displacement, the head 4
Can be coated with metal.

FIG. 3 shows a second embodiment of the friction force detecting cantilever according to the present invention. In the cantilever for detecting a frictional force of the second embodiment, as in the case of the first embodiment shown in FIG. 1, parallel plate springs 3 which are perpendicular to the surface of the sample 1 are opposed to each other at intervals. The cantilever body 2 is constituted by a single leaf spring 8 which can provide an arbitrary spring constant with respect to vertical displacement at the base end of the cantilever body 2. The cantilever main body 2 is attached to a base 7 attached to a friction force microscope through the base. A head similar to that of the first embodiment is provided at the tip of the cantilever body 2.

FIG. 4 shows a third embodiment of the friction force detecting cantilever according to the present invention. The frictional force detecting cantilever of the third embodiment is, as in the case of the first embodiment of FIG. , A cantilever body 2 is provided, and a parallel leaf spring 9 capable of giving an arbitrary spring constant to vertical displacement is interposed at the base end of the cantilever body 2, and the cantilever body 2 is provided via the parallel leaf spring 9. The cantilever body 2 is attached to a base 7 attached to a friction force microscope. Also, the cantilever body 2
A head similar to that of the first embodiment is provided at the tip of the head.

Note that the second and third embodiments are
Except that the leaf spring 8 or the parallel leaf spring 9 is provided, the structure and the operation based on the structure are the same as those of the first embodiment, and are the same as or equivalent to those of the first embodiment in FIGS. The same reference numerals are given to the portions and the description thereof is omitted.

[0014]

According to the cantilever for detecting a frictional force of the present invention described in detail above, a plurality of mutually parallel leaf springs which are perpendicular to the surface of the test sample are opposed to each other at intervals, and the tip of the leaf spring is connected to the tip of the leaf spring. The cantilever body is constructed by restraining the base, and the head at the tip of the cantilever body depends on the position of the head.
Cylindrical surface with different laser light reflection angle for displacement detection
Or sphere-shaped protrusions or depressions
Since the reflecting surface is provided with the probe is displaced laterally without changing the angle with the head, without reducing the torsional rigidity, therefore
Te, twisting the influence of deformation can be detected frictional force with little subjected, also set any frictional force detection sensitivity, precision friction force distribution measurements, invariant of the probe tip portion contacting the sample Can be realized.

[Brief description of the drawings]

FIG. 1 is a first view of a friction force detecting cantilever according to the present invention.
It is a perspective view showing the composition of an example.

FIG. 2 is a perspective view showing a use state of the embodiment.

FIG. 3 is a second view of a friction force detecting cantilever according to the present invention.
It is a perspective view showing the composition of an example.

FIG. 4 is a third view of the frictional force detecting cantilever according to the present invention;
It is a perspective view showing the composition of an example.

FIG. 5 is a perspective view showing a configuration example of a conventional cantilever for detecting frictional force.

FIG. 6 is a perspective view showing the same use state.

[Explanation of symbols]

 Reference Signs List 1 sample 2 cantilever body 3 leaf spring 4 head 5 probe 6 reflection surface 7 base 8 leaf spring 9 parallel leaf spring

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 13/10-13/24 G12B 21/00-21/24 G01B 21/30 G01B 7/34 H01J 37 / 28 JICST file (JOIS)

Claims (2)

(57) [Claims] 1. A cantilever body comprising: a plurality of leaf springs which are perpendicular to a surface of a test sample and are opposed to each other at intervals; and both ends of the leaf springs are mutually restrained. Then, the base end can be fixed to the base attached to the friction force microscope, a block-shaped head is provided at the tip of the cantilever body, and a probe is provided on the surface of the head facing the sample side. ,
A cylindrical or spherical projection with a different reflection angle of the laser beam for displacement detection depending on the position of the head is placed on the head.
A cantilever for detecting a frictional force, comprising a reflecting surface formed by a portion or a recess . 2. A cantilever attached to a base of a friction force microscope.
At the base end of the lever body,
The cantilever for frictional force detection according to claim 1, wherein a plurality of parallel leaf springs for giving a spring constant are interposed .