JPH0373416B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a positioning table device, and more specifically, it uses piezoelectric effects to move parts to fixed positions and control the posture of robots. Alternatively, the present invention relates to a positioning table device used in IC wafer inspection processes, etc., for precisely horizontally displacing the table.

[Conventional technology]

Conventionally, there is a device of this type proposed by the present inventor (Japanese Patent Application No. 175,640/1989), which is
A plurality of piezoelectric element units are used in which a thickness effect element defined by a piezoelectric constant d ₃₃ and a thickness sliding effect element defined by a piezoelectric constant d ₁₅ are laminated and integrated, and the sliding directions are the X and Y directions, respectively. The first and second piezoelectric element units are arranged with their lower surfaces fixed to the upper surface of a single base, and the upper surface is adapted to be engaged with and detached from a table.

With this configuration, while the table is moved up and down by the expansion and contraction of the thickness effect element of the second piezoelectric element unit, the thickness effect element and the thickness sliding effect element of the first piezoelectric element unit are respectively operated in a timely manner to move the table in the X direction. move in the direction.

To move the table in the Y direction, first and second
The operations of the piezoelectric element units are opposite to each other.

Another device for rotationally displacing the table about the vertical axis is a device in which a plurality of the first and second piezoelectric element units are arranged alternately on the same circumference, and the above operation is caused to occur in each piezoelectric element unit. This is done by making the

[Problem that the invention seeks to solve]

The conventional positioning table device as described above has a problem in that the table cannot be moved in the X, Y directions and rotationally with the same device.

This invention aims to solve these problems, and aims to provide a positioning table device that can cause displacement in the X and Y directions and rotational displacement in the table using the same device. be.

[Means for solving problems]

The positioning table device according to the present invention uses a plurality of piezoelectric element units in which a thickness effect piezoelectric element and first and second sliding effect piezoelectric elements in mutually orthogonal directions are laminated and integrated.

Further, the lower surface of each piezoelectric element unit is fixed to a single base, and the upper end of each piezoelectric element unit is selectively engaged with and detached from the lower surface of the table.

[Effect]

In this invention, when a specific piezoelectric element unit drives the table up and down, other piezoelectric element units displace the table along a straight line orthogonal to each other and rotationally displace the table about a vertical rotation axis. .

〔Example〕

1 to 3 show an embodiment of this invention,
As illustrated in FIG. 3, the piezoelectric unit includes thickness effect elements 3a to 3d, first sliding effect elements 4a and 4b in the X direction, and second sliding effect elements 5a and 5b in a direction perpendicular to the X direction. The magnets are laminated and integrated, input terminals 1, 2a, and 2b are connected in parallel, and a holding member 7 for holding a magnet 6 is coupled to the upper surface.

The piezoelectric element units u ₁ to _{u 4} as described above are
As shown in FIG. 2, the lower surface is fixed to the upper surface of the base 8. That is, in the first piezoelectric element units u ₃ and u ₄ , the first sliding effect elements 4a and 4b in the X direction perform a sliding operation in the same direction, and the second sliding elements 5a and 4b in the direction perpendicular to the X direction perform a sliding operation. 5b slide in opposite directions, and are arranged symmetrically with respect to the vertical rotation axis O of the table 9.

The piezoelectric element units u ₁ and u ₂ have first sliding effect elements 4a and 4b that perform sliding motion in the same direction in the Y direction,
It is provided with second sliding effect elements 5a, 5b which perform sliding operations in the same circumferential direction as the second sliding effect elements 5a, 5b of the piezoelectric element units _u3 , _u4 at right angles to the Y direction.

With the above configuration, the table 9 made of a magnetic material is attracted to the magnet 6. First, in order to displace the table 9 in the X direction, the piezoelectric element unit is
While applying vertical expansion and contraction to u ₁ and u ₂ , the thickness effect elements _{3 a} to 3 d and the first sliding effect elements 4 a and ₄ b of piezoelectric element units u 3 and u 4 are operated in a timely manner, and piezoelectric element units u ₃ , As u ₄ is bent in the X direction, the table 9 is displaced in the X direction. The direction of the displacement at this time is determined by the combination of the polarity of the voltage applied to the terminal 2 and the polarization direction of the first sliding effect elements 4a, 4b.

As described above, the displacement of the table 9 in the X direction is driven only by the first sliding effect elements _4a , 4b of the piezoelectric elements u 3 , u ₄ , and at this time, the piezoelectric element units u ₁ , u ₂
is responsible for driving the table 9 up and down.

The displacement of the table 9 in the Y direction is determined by the piezoelectric element unit.
u ₁ and u ₂ carry the displacement drive, and the piezoelectric element unit
u ₃ and u ₄ carry the vertical drive and operate in the same way.

Next, in order to give the table 9 a rotational displacement θ about the vertical rotation axis O, for example, when rotating the table 9 _{counterclockwise} in FIG _. In order to drive the displacement by only the second sliding effect element 5a, 5 of the piezoelectric element unit _u3
This is achieved by applying a sliding strain to b in the +Y direction and to the second sliding effect elements 5a and 5b of the piezoelectric element unit _u4 in the -Y direction.

At this time, if the piezoelectric element units u ₁ , u ₂ and u ₃ , u ₄ are made into one set each and are made to alternately bear rotational drive, then
The rotational displacement speed of the table 9 increases twice.

Incidentally, if the X and Y directions are driven simultaneously at the same speed, the table 9 will move in the 45° direction.

As mentioned above, the speed of displacement in the X and Y directions and rotational displacement depends on various factors such as the magnitude of the voltage applied to the piezoelectric effect element, the frequency of repetition of voltage application, the magnitude of the piezoelectric constant, and the dimensions and number of piezoelectric effect elements. However, these are design issues when implementing this invention.

The magnet 6 is attached to a gutter-shaped or box-shaped holding member 7.
A magnet 6 made of ferrite may be magnetized and fixed in the direction shown by arrow M in FIG. Therefore, when the electrical circuit to the piezoelectric element is cut off, the four piezoelectric element units u ₁ to u ₄ in FIG.
The tips of the holding members 7 all attract and hold the table 9, and when the table 9 enters the mode of displacement, the two opposing piezoelectric element units u ₁ , u ₂ and u ₃ , u ₄ requires timely adsorption and retention at high frequency.

Although the magnet is fixed to the holding member 7, the table 9 can be easily attached and detached depending on the content of the attachment and detachment operation of the table 9, if the magnet can be freely inserted and removed.

Further, the arrows in FIG. 3 indicate the directions of each polarization, and the polarization directions of the elements 3a to 3b and 4a, and 4b and 5a and 5b are orthogonal to each other.
Furthermore, the mutual vertical positions of these elements are not limited to the above embodiments, and may be arbitrary.

In addition, the number of piezoelectric element units and the number of elements connected in parallel can be selected depending on the application. For example, if the speed of displacement in the _X direction is important, the first _sliding of piezoelectric element units Effect element 4a,
Particular consideration should be given to the number and material (mainly hysteresis) of the 4b.

Furthermore, a single drive power source is sufficient, and by controlling the inputs to input terminals 1, 2a, and 2b with appropriate phases, the table can be displaced in the X, Y, and θ directions at any speed and stride length. It can be done smoothly.

FIG. 4 shows another embodiment, in which the piezoelectric element unit
u ₁ to _{u 4} have a trapezoidal planar cross-sectional shape, and are arranged with their short sides facing each other.

With this configuration, the spacing between the piezoelectric element units becomes narrower, and even if the table 8 is made thinner, it can still have sufficient strength. Furthermore, as the table 8 is made lighter, the base 9 can also be made thinner.

Furthermore, in the above embodiment, an example was described in which the arrangement and positional relationship of each piezoelectric unit is arranged in a cross pattern, but this arrangement is not limited to a cross pattern arrangement as long as the above operations can be performed smoothly, for example, a rectangular arrangement. This can also be achieved by

In this case as well, the polarization direction of the piezoelectric elements is stacked and arranged so that they operate as shown in the above example.
Naturally, performance when two piezoelectric element units are installed in parallel in each of the X and Y directions is determined by selecting balanced piezoelectric element units. Further, in the above embodiment, an example was shown in which the table is attracted and fixed by a magnet, but if the entire table is made of non-magnetic material, the base 8 and the table 9 may be connected with a spring to apply a constant bias. Just leave it there.

〔Effect of the invention〕

As is clear from the above explanation, this invention
The first direction in the direction orthogonal to the thickness effect piezoelectric element,
Two pairs of piezoelectric element units in which second sliding effect piezoelectric elements are laminated and integrated are arranged symmetrically with respect to the vertical rotational axis of the table, with their lower surfaces fixed, and displacement or rotational displacement in two directions perpendicular to the table. This has the effect that linear displacement and rotational displacement of the table can be obtained simultaneously or separately with a single one-stage device.

[Brief explanation of drawings]

FIG. 1 is a plan view of a main part of one embodiment of the present invention, FIG. 2 is a front view of the same, FIG. 3 is a partial front view of the same, and FIG. 4 is a plan view of a main part of another embodiment. 1, 2a, 2b...Input terminal, 3a to 3d...Thickness effect piezoelectric element, 4a, 4b...First slipping effect piezoelectric element, 5a, 5b...Second slipping effect piezoelectric element, 6
... Magnet, 7... Holding member, 8... Base, 9... Table, _u1 to _u4 ... Piezoelectric element unit, O... Vertical rotation axis.

Claims (1)

[Scope of Claims] 1. A thickness-effect piezoelectric element, a first sliding-effect piezoelectric element, and a second sliding-effect piezoelectric element that performs sliding motion in mutually opposite directions perpendicular to the first sliding-effect piezoelectric element. a plurality of piezoelectric element units laminated together; a base on which the plurality of piezoelectric elements are fixed and disposed; A positioning table device comprising: a table on which is placed; 2. The positioning table device according to claim 1, comprising a magnet attached to the upper end of the piezoelectric element unit, and a table attracted to the magnet. 3 arranged symmetrically with respect to the vertical rotation axis on a first straight line orthogonal to the vertical rotation axis of the table, including a thickness effect piezoelectric element and a first sliding effect piezoelectric element in the first linear direction; a pair of piezoelectric element units formed by laminating and integrating second sliding effect piezoelectric elements that are perpendicular to the first straight line and are oriented in opposite directions; The thickness-effect piezoelectric element and the first sliding-effect piezoelectric element are disposed symmetrically with respect to the rotation axis, and the second sliding-effect piezoelectric element is orthogonal to the second linear direction and is oriented in opposite directions. a pair of piezoelectric element units formed by laminating and integrating piezoelectric elements; a base to which a lower surface of each of the piezoelectric element units is fixed; A positioning table device comprising: the table placed on a piezoelectric element unit.