JPH05316712A - Biaxial stage apparatus - Google Patents

Abstract

PURPOSE:To reduce the size of a drive source by disposing a stator of a linear motor for moving a stage in an X direction to a rear side of a board, and mounting its moving element in the motor of a front side of the board for moving the stage in a Y direction. CONSTITUTION:A pair of guides 2a, 2b of an X-axis direction and a sliders 3a, 3b are provided on a front side of a board 1. A yoke 43 and a coil 44-n (n=1-n) for forming a stator of an X-axis linear motor 4 are provided on a lower surface of the board. A moving element 44 is mounted in a Y-axis linear motor 5 on an upper surface of the board by aligning permanent magnets 46-m alternately magnetized in opposite polarities in a thickness direction in an X-axis direction. A stator 51 of the motor 5 has a Y-axis base 54 and a yoke 54 on the sliders 3a, 3b, Y-axis driving permanent magnets 55-n alternately magnetized in opposite polarities in a thickness direction are arranged in a Y-axis direction, and a yoke 52 is moved in the Y-axis direction. Thus, the moving element of the motor 4 is disposed directly under a center of gravity of the motor 5 to prevent axial deviation and to reduce of the size of a driving system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stage device for conveying a stage such as a pen unit of an XY plotter to a predetermined position, and more particularly to a rectangular coordinate type stage device for driving the stage by a linear DC motor.

[0002]

2. Description of the Related Art Multi-pen XY blocks are generally used for terminal devices such as computer graphics and CAD. In this type of plotter, the pen unit is conveyed to a predetermined position for drawing, but the stepping motor and the brushless D are used as the feeding mechanism of the pen unit.
A linear motion mechanism in which a wire or a timing belt is driven by a rotary motor such as a C motor has been adopted.

However, with such a mechanism, there are problems that the drawing speed is slow, the coordination of each operation of the X-axis and the Y-axis is difficult, and the figure is easily distorted, and high-speed and ultra-precision drawing is possible. There is a problem that it cannot be applied to the required printing XY plotter. Therefore, in order to solve such a problem, for example, JP-A-62-254682 and JP-A-62-6418
As disclosed in No. 6, a method of driving a stage such as a pen unit by a linear DC motor is under study.

[0004]

However, in the conventional XY stage apparatus, the X-axis linear DC motor and the Y-axis linear DC motor are independently operated to move the stage in both the X-axis and Y-axis directions. Are arranged. For this reason, there is a drawback that the stage device becomes large and the structure becomes complicated. Therefore, an object of the present invention is to provide a biaxial stage device which is compact and which enables high-speed and high-precision feeding of the stage.

[0005]

In order to achieve the above object, the present invention provides a substrate, a stage that linearly moves on the substrate in a first direction and a second direction orthogonal to the first direction, and the stage includes the substrate. A guide member supported above, a first linear DC motor that drives the stage in the first direction, and a second linear DC motor that drives the stage in the second direction, The first linear DC motor has a stator fixed to the back surface of the substrate and a mover fixed to the lower portion of the second linear DC motor,
The mover employs a technical means of being arranged immediately below the center of gravity of the second linear DC motor.

[0006]

According to the present invention, the stator of the first linear DC motor for reciprocating the stage in the first direction (X-axis) is arranged on the back surface of the substrate, and the mover of the first stage is used as the stage. Since it is attached to the second linear DC motor for reciprocating in the two directions (Y axis), the drive source can be made significantly compact. Further, in the present invention, in addition to the two linear DC motors being arranged in two stages as described above, since the thrust generation point is directly below the center of gravity of the second linear DC motor, the second linear DC motor Axis deviation can be prevented based on the generation of a moment associated with the movement of the center of gravity when driving.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. 1 and 2, the substrate 1 includes a support plate 11 and an electrostatic sheet 12 placed on the support plate 11. A pair of guides 2a and 2b are extended on the substrate 1 in the X-axis direction.
X-axis sliders 3a and 3b are slidably mounted on 2b, respectively. 4 is an X-axis linear DC motor,
It includes a stator 41 and a mover 42. The stator 41 includes an X-axis yoke 43 made of a ferromagnetic material and an X-axis yoke 43 inside the yoke.
A plurality of X-axis drive coils 44-1 fixed in the axial direction,
44-2, ... 44-n (n: an integer of 2 or more), and the X-axis yoke 43 is fixed to the lower surface of the support plate 11 by fixing plates 45a and 45b. Both terminals of each of these drive coils are connected to a drive circuit (not shown), and both output terminals of a position detection element (not shown) arranged on the conductor portion that contributes to the thrust of the drive coil. Is connected to the drive circuit. The mover 42 includes X-axis drive permanent magnets 46-1, 46-2, ... 46 magnetized in the thickness direction.
-N, (n: an integer equal to or greater than 2) is attached to the Y-axis linear DC motor 5 so that magnetic poles of opposite polarities are alternately arranged in the X-axis direction.

Next, the Y-axis linear DC motor 5 includes the stator 5
1 and a mover 52. The stator 51 includes a Y-axis base 53 fixedly mounted on the X-axis sliders 3a and 3b at both ends in the Y-axis direction, and a Y fixed to the base 53.
The shaft upper yoke 54 is included. The Y-axis base 53 is made of a ferromagnetic material like the upper yoke 54 and also serves as the lower yoke. Also, on the upper surface of the Y-axis base 53,
Y-axis drive permanent magnets 55-1 and 5-5 magnetized in the thickness direction
55-n (n: an integer of 2 or more) are fixed so that magnetic poles of different polarities are alternately arranged in the Y-axis direction. Furthermore, the above-mentioned X-axis drive permanent magnet 46-n is fixed so as to be positioned on the lower surface of the Y-axis base 53 and between the X-axis sliders 3a and 3b. That is, in the present invention, the mover 42 of the X-axis linear DC motor 4 is arranged so as to be located immediately below the center of gravity of the Y-axis linear DC motor 5. The mover 52 includes a core 56, a Y-axis drive coil 57 having a plurality of flat coils arranged in the Y-axis direction, an upper slider 58, and a lower slider 5 fixed to the lower portion thereof.
9a and 59b. Lower sliders 59a, 59
b is a guide 60 fixed on the Y-axis base 53.
It is slidably fitted on a and 60b. Also coil 5
Both terminals of 7 are connected to a drive circuit (not shown) and a position detecting element (not shown) provided on the mover 52.
Is connected to the drive circuit.

Next, the operation of the above-mentioned two-axis stage device will be described. When driving the X-axis linear DC motor 4, when a current is passed from the drive circuit to the X-axis drive coil 44-n, the position detection element provided in each coil causes the X-axis drive permanent magnet 46 to move.
Since the magnetic fluxes of the N pole and the S pole of −n are detected, and the current flowing through the coil is orthogonal to the magnetic field of the permanent magnet 46-n,
A thrust force in the direction of the arrow in the figure is applied to the coil by Fleming's left-hand rule, and the mover 42 moves in that direction. In order to move the mover 42 in the direction opposite to the arrow, the polarities of both terminals of the drive circuit may be changed. When driving a Y-axis linear DC motor, when a current is passed from the drive circuit to the Y-axis coil 57, the current flowing through the coil is orthogonal to the magnetic field generated by the permanent magnet 55-n. For example, thrust in the direction of the arrow in the figure is obtained, and the mover 52 also moves in that direction. When a current in the opposite direction to the above is applied to the coil, the coil, that is, the mover moves in the opposite direction.

In the case of a multi-stage structure in which both the X-axis drive means and the Y-axis drive means of the two-axis stage device are linear DC motors, and the other drive means is laminated on one drive means, and the range of movement of the stage Is wide (eg X axis, Y
In the case where both axes are several hundred mm to 1 m), a moment is generated due to the movement of the center of gravity, and there is a concern that the axis may be displaced. However, with the structure of the above-described embodiment, the X-axis linear DC motor has the thrust generation point substantially immediately below the center of gravity of the Y-axis linear DC motor, so that the occurrence of axis deviation can be effectively prevented. it can. In the above embodiment, the mass of the moving part of the stage device is about 1.5 k, which is the total weight of the mover of the Y-axis linear DC motor and the pen unit.
It was g. Here, the moving distances in the X-axis direction and the Y-axis direction are 1.2 m and 1 m, respectively.

In the above embodiment, the X-axis linear DC motor is the moving magnet type linear motor, and the Y-axis linear DC motor is the moving coil type linear motor. However, the structure of the Y-axis linear motor is used for the stage device. It may be determined according to the For example, in the case of a pen unit feed mechanism,
Since the mass of the pen unit is at most about 600 to 800 g, it is possible to reduce the weight of the Y-axis linear motor by reducing the weight of the mover. Therefore, in the above embodiment, the Y-axis linear motor is of the moving coil type. In this case, the weight of the mover alone is 650 g. In the case of the moving coil system, a plurality of cables are routed, but if there is a great need to reduce the number of cables, then Y
The axial linear motor may also be of the movable magnet type.

[0012]

As described above, according to the present invention,
The stator of the first linear motor that reciprocates the stage in the first direction is provided on the back surface of the substrate, and the mover is attached to the lower portion of the second linear DC motor that reciprocates the stage in the second direction. Therefore, a stage device having a compact structure can be obtained. Further, since the mover of the first linear DC motor is located immediately below the center of gravity of the second linear DC motor, it is possible to prevent the axis deviation.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 1 substrate 2a, 2b guide 3a, 3b X-axis slider 4 X-axis linear motor 41 stator 42 mover 5 Y-axis linear motor 51 base

Claims (2)

[Claims] 1. A substrate, and a stage that linearly moves on the substrate in a first direction and a second direction orthogonal thereto.
A guide member that supports the stage on the substrate, a first linear DC motor that drives the stage in the first direction, and a second linear DC motor that drives the stage in the second direction. The first linear DC motor has a stator fixed to a back surface of the substrate and a mover fixed to a lower portion of the second linear DC motor, and the mover is A two-axis stage device, which is arranged immediately below the center of gravity of a second linear DC motor. 2. The biaxial stage apparatus according to claim 1, wherein at least one of the linear DC motors has a stator including a drive coil and a mover including a permanent magnet.