JPH0433361B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fine movement device, and more specifically, it is suitable for various precision instruments including scanning tunneling microscopes.
Two axes of X and Y that are orthogonal to each other or X,
The present invention relates to a fine movement device capable of fine movement in units of angstroms independently in the three axis directions of Y and Z.

[Conventional technology]

Conventionally, this type of fine movement device has been proposed to use a piezoelectric element or an electrostrictive element. There are devices in which three sides of the device are hollowed out to form a tripod shape, that is, a shape with holes on three sides, and devices in which one axis is independent or the other two axes are formed in a letter shape.

However, with these fine movement devices, the expansion and contraction that acts on one axis also affects the other two axes, resulting in 3
It is not possible to move the axes independently and precisely, and in order to prevent such interference with other axes, it has been proposed in recent years that multiple piezoelectric elements or electrostrictive elements are bonded together with adhesive. It has been.

[Problem that the invention seeks to solve]

Although the above-mentioned fine movement device can achieve independent fine movement in three axial directions, there is a problem of hysteresis due to the use of adhesive, and furthermore, there is a delay in high-speed fine movement. There are drawbacks that cannot be overlooked as a fine movement mechanism, such as
These drawbacks have a serious impact on the performance of scanning tunneling microscopes, which are capable of making measurements at the atomic level.

An object of the present invention is to focus on the above-mentioned problems, and to solve the problems, it is an object of the present invention to provide a fine movement device that is capable of fine movement independent of each other in three axial directions and that guarantees reliability in terms of performance and operation. Our goal is to provide the following.

[Means for solving problems]

In order to achieve such an object, the present invention provides a rectangular parallelepiped piezoelectric drive unit with a counter electrode, applies a voltage to the counter electrode to generate displacement in a direction perpendicular to the direction of voltage application, and measures the displacement. In a fine movement device in which movement in the displacement direction of piezoelectric actuators can be controlled by driving members connected in sequence with their forming surfaces facing at right angles to each other;
A support member that supports the other end of the terminal piezoelectric drive unit among the connected drive members, and a means for supplying an applied voltage to the electrodes of each piezoelectric drive unit, and the direction of connection by the plurality of piezoelectric drive units It is characterized in that it is arranged to be displaced independently of each other in at least two of the three mutually orthogonal axes including the three axes.

[Effect]

In the fine movement device of the present invention, independent fine movement generation mechanisms in three axes provided in one single element allow fine movement in each direction without affecting the fine movement generation mechanism of the other axis. can be carried out.

〔Example〕

Embodiments of the present invention will be described in detail and specifically below based on the drawings.

FIG. 1 shows an embodiment of the invention. This example is an example in which this three-dimensional fine movement device is applied to the probe of a scanning tunneling microscope. In FIG. 1, reference numeral 1 denotes the fine movement device, which is formed by processing an integral piezoelectric material such as piezoelectric ceramics or crystal into the shape shown in the figure. That is, in this example, the piezoelectric actuator is formed in a continuous U-shape with respect to the three axes X, Y, and Z that intersect at right angles to each other, and the opening direction is made to differ in each of the four horizontal directions. The piezoelectric drive unit 1A, 1
Among B, 1C, 1D, 1F, 1G, 1H and 1K, 1A, 1C, 1G and 1K are parallel to the XY plane, 1B and 1D are parallel to the XZ plane, and 1F,
1H is formed parallel to the YZ plane, and furthermore, a horizontal connecting portion 1E is provided between the piezoelectric driving portions 1D and 1F, which are different in the vertical direction, among the piezoelectric driving portions.

Thus, one end of the piezoelectric drive unit 1K is extended and fixed to the support member 2, and the other part of the other piezoelectric drive unit 1A is extended and the probe 3 is fixed there. Furthermore, as shown in FIGS. 2 and 3, each piezoelectric drive section is provided with electrodes for applying a drive voltage on both its upper and lower surfaces or vertical surfaces, and 21A and 31A are piezoelectric drive sections. The electrodes 21B and 31B are provided on the piezoelectric drive unit 1B, and the electrodes 21C, 31C, and 2
1D and 31D, 21F and 31F, 21G
and 31G, 21H and 31H, 21K and 31K are piezoelectric drive units 1C, 1D, 1, respectively.
These are the electrodes provided at F, 1G, 1H and 1K.

Furthermore, in FIGS. 2 and 3, 40
is a drive control power source in the x-axis direction, 50 is a drive control power source in the Y-axis direction, and 60 is a drive control power source in the Z-axis direction, and the individual power supplies 40, 50, and 60 are for the X, Y, and Z directions, respectively. The electrodes are connected so that a voltage is applied between the opposing electrodes to independently generate displacements of the electrodes.

That is, to explain FIG. 1, piezoelectric actuators 1G and 1K act as fine movement mechanisms in the X direction, piezoelectric actuators 1A and 1C act as fine movement mechanisms in the Y direction, and piezoelectric actuators 1B, 1D, 1F and 1H act as fine movement mechanisms in the Z direction. For example, in the piezoelectric actuators 1A and 1C, these opposing electrodes 21
If a voltage is applied between A and 31A and between 21C and 31C, the polarity of the voltage and the piezoelectric drive unit 1
The space between the electrodes expands and contracts in accordance with the piezoelectric constants of A and 1C, thereby allowing displacement in the Y direction, that is, fine movement, regardless of other directions. In this way, fine movement in the X direction and Y direction can be performed by configuring fine movement mechanisms in the respective independent directions in the same manner, and these fine movement mechanisms are provided in the middle of the connecting portion 1E. The structure is such that rigidity is maintained against bending by connecting the two piezoelectric actuators 1D and 1F, which are oriented in different directions, and this has the effect of preventing the natural frequency from dropping excessively. That's what you get.

Note that, for example, the electrodes 21A and 31A of the piezoelectric drive unit 1A and the electrodes 21C and 3 of the piezoelectric drive unit 1C
If the polar directions of the voltages applied to 1C and 1C are controlled to be reversed, one side will expand and the other will contract, making it possible to generate twice the amount of fine movement in the Y-axis direction. It is also possible to perform this in the X-axis direction. In this case, since elongation and contraction are used for micromovement in the same direction, there is also the advantage that the amount of displacement due to elongation and contraction that occurs in the direction perpendicular to this, that is, the amount of movement, can cancel each other out. be able to. In addition, in the Z-axis direction, by applying an electric field in the same direction to the four piezoelectric drive units 1B, 1D, 1F, and 1H, fine movement with a correspondingly large amount of displacement is possible.

In the above explanation, the electrodes are provided on the upper and lower opposing surfaces of the horizontal piezoelectric drive section or on the outer circular opposing surfaces of the vertical piezoelectric drive section. Depending on the relationship with the distance, it is also possible to arrange the electrodes on their side ends, for example, in the case of the piezoelectric actuators 1A and 1C, at opposing positions on the YZ plane.

In addition, in this example, a single piezoelectric material was molded.If the individual piezoelectric drive parts were formed as a rectangular parallelepiped flat plate and then glued together, hysteresis that occurs in the bonded parts at the atomic level will occur over time. This is due to the judgment that there is a risk that the performance of the fine movement mechanism itself may deteriorate.

Furthermore, although this example describes the configuration as a three-dimensional fine movement device, the application of the present invention is not limited to a three-dimensional fine movement device; for example, other means may be used for fine movement in the Z-axis direction. It is also possible to obtain a two-dimensional fine movement device in which the length in the Z-axis direction of the piezoelectric drive unit that shares the fine movement in the Z-axis direction is extremely shortened, and the natural frequency is increased.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to independently perform fine movements in two or three axes using a single piezoelectric element without affecting fine movements in other directions, and Since there is no interference between them, the reliability of fine movement in each axial direction is increased, and furthermore, by connecting the piezoelectric drive members parallel to each other in a U-shape,
By expanding and contracting these, it is possible to double the amount of displacement, for example, and in this case, there is an advantage that the displacement in the direction perpendicular to the displacement direction is canceled out, and the reduction in the natural frequency of the voltage element is also suppressed. Accordingly, it is possible to provide a fine movement device that is widely suitable for scanning tunneling microscopes and various precision instruments.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of the configuration of the fine movement device of the present invention together with its fine movement direction, and FIGS. 2 and 3 show the drive section of the fine movement device shown in FIG. It is a block diagram shown as seen from each direction. 1... Fine movement device, 1A, 1B, 1C, 1D, 1
E, 1F, 1G, 1H, 1K...Piezoelectric drive unit, 1
E...Connection part, 21A, 31A, 21B, 31
B, 21C, 31C, 21D, 31D, 21F,
31F, 21G, 31G, 21H, 31H, 21
K, 31K... Electrode, 40, 50, 60... Power supply.

Claims (1)

[Claims] 1. A rectangular parallelepiped-shaped piezoelectric drive unit is provided with a counter electrode,
A fine movement device capable of generating displacement in a direction perpendicular to the voltage application direction by applying a voltage to the opposing electrode, and controlling movement of the piezoelectric drive unit in the displacement direction by the displacement, comprising: a plurality of piezoelectric drive units; a driving member which is integrally formed of a piezoelectric or electrostrictive material, and in which one ends of the individual piezoelectric driving parts are successively connected to each other such that the electrode formation surfaces thereof face each other in a direction perpendicular to each other; a support member that supports the other end of the piezoelectric drive unit at the terminal end of the drive member, and means for supplying an applied voltage to the electrodes of the individual piezoelectric drive units, the plurality of piezoelectric drive units At least two of three mutually orthogonal axes including the direction of connection
A fine movement device characterized by being configured to be displaced independently of each other in the axial direction.