Geometrical instruments – Miscellaneous – Light direction
Reexamination Certificate
2002-05-15
2004-11-16
Gutierrez, Diego (Department: 2859)
Geometrical instruments
Miscellaneous
Light direction
C033S568000, C033S573000
Reexamination Certificate
active
06817104
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an X-Y stage apparatus provided with a moving table that can move within an XY plane, and which can position a component mounted on top of the moving table within the XY plane.
2. Description of the Related Art
In the past, this type of X-Y stage apparatus has been used in many industrial fields, such as mounting apparatuses of electronic components (chip mounter) machine tools, and controlling mechanism of optical systems (lens, mirrors, and others).
FIG. 15
shows a conventional X-Y stage apparatus
900
. This X-Y stage apparatus
900
has a Y-axis guiding mechanism
906
with an X-Y table
907
, mounted on top of an X-axis table (not shown) of an X-axis guiding mechanism
903
. The X-axis guiding mechanism
903
is provided with an X-axis ball screw
902
arranged in an X-axis direction, and an X-axis servomotor
901
that rotates and drives this X-axis ball screw
902
. The whole Y-axis guiding mechanism
906
is moved and positioned in the X-axis direction by controlling this X-axis servomotor
901
, as appropriate. The Y-axis guiding mechanism
906
is provided with a Y-axis ball screw
905
arranged in a Y-axis direction, and a Y-axis servomotor
904
that rotates and drives this Y-axis ball screw
905
. The X-Y table
907
is moved and positioned in the Y-axis direction by controlling this Y-axis servomotor
904
, as appropriate. Therefore, the location of the X-Y table
907
can be positioned in the X-axis and Y-axis directions by controlling the X-axis and Y-axis servomotors
901
and
904
.
For controlling methods of the X-axis and Y-axis servomotors
901
and
904
, there is for example, a semi-closed-loop control method that surmises the amount of movement of the X-Y table
907
from the rotating amount of the X-axis and Y-axis ball screws
902
and
905
, which is measured by encoders, and controls the X-axis and Y-axis servomotors
901
and
904
with these surmised values. There is also a fully-closed-loop control method that directly measures the amount of movement of the X-Y table
907
with a linear gauge or the like, and feedback controls the X-axis and Y-axis servomotors
901
and
904
with these values.
In recent years, the demand for “high-speed control” and “precision control” of an X-Y table
907
has been enhanced, corresponding with the advancement in technology. When trying to accomplish high-speed control, there was a limit in making the control speed faster with a driving method using a shaft mechanism with ball screws
902
and
905
, because vibration increased, for example, when changing between normal rotation and reverse rotation, or when accelerating or decelerating rapidly. When trying to accomplish precision control with the semi-closed-loop control method, it was difficult to control the X-Y table
907
with precision, because there were no considerations for a bending of each of the ball screws
902
and
905
, or for backlashes, or the like.
It was possible to achieve a more precise control with the fully-closed-loop control method, but the position measuring signals of the X-Y table
907
became unstable, because the vibration of each of the ball screws
902
and
905
was transmitted to the X-Y table
907
, when the controlling speed went up. As a result, there was a problem that the responsiveness of the feedback control could not be enhanced, what with the signal becoming unstable.
Furthermore, since the X-Y stage apparatus
900
had a two-tiered construction, with the Y-axis guiding mechanism
906
mounted on top of the X-axis guiding mechanism
903
, the center of gravity was high, and an overturning moment was prone to be generated. As a result, positioning error increased because a swing of the X-Y table
907
was generated, when controlling a rapid acceleration or deceleration. In the case of such two-tiered construction, the whole Y-axis guiding mechanism
906
becomes a moving load (inertia-load) for the X-axis guiding mechanism
903
located at the bottom tier, but only the X-Y table
907
becomes the moving load for the Y-axis guiding mechanism
906
. Hence, there was a difference in the responsiveness of control in the X-axis direction, and the control in the Y-axis direction. When driving the X-Y table
907
in both of the X-axis and the Y-axis directions at the same time, as in drawing a circle, or moving in a diagonal direction of the X-Y axes, for example, there arose a problem that precision deteriorated, and it was difficult to realize high-speed control.
SUMMARY OF THE INVENTION
The present invention was made in view of the above-mentioned problems, and it is an object of this invention to achieve an X-Y stage apparatus compact in constitution, and which can control with high-speed, and with high-precision.
This invention achieves the above-mentioned objects by providing an X-Y stage apparatus comprising a stationary base, and a moving table that can be displaced within an XY plane relative to the stationary base, provided that an X-axis, a Y-axis, and a Z-axis are at right angles to each other. The X-Y stage apparatus is provided with a plurality of elastic hinges of one or more types, which have flexible characteristics only in one or two directions among the X-axis, Y-axis, and Z-axis directions, and rigid characteristics in the other directions. The elastic hinges are arranged along one direction among the X-axis, Y-axis, and Z-axis directions, and allows relative displacement between members connected to both sides of the hinges only in the flexible direction. The moving table is supported within the XY plane relative to the stationary base with slight displacement made possible by utilizing an elastic deformation of each of the elastic hinges in the aforementioned flexible direction. Moreover, the X-Y stage apparatus is provided with an X-axis linear motor which has a stator portion and a moving portion arranged on the stationary base and the moving table, respectively, and which can move the moving table in the X-axis direction, relative to the stationary base. The X-Y stage apparatus is also provided with a Y-axis linear motor which has a stator portion and a moving portion arranged on the stationary base and the moving table, respectively, and which can move the moving table in the Y-axis direction relative to the stationary base. In this constitution, the moving table is displaced slightly within the XY plane relative to the stationary base by the X-axis and Y-axis linear motors.
In this X-Y stage apparatus, the inventor of this invention adopted a constitution provided with an “elastic hinge” that supports the moving table in a movable state in the X-Y axis direction, and a “linear motor” that drives the moving table.
The basic construction of the elastic hinge itself is publicly known, and in general, has characteristics being flexible only in one particular direction and rigid in the other directions, and has a function that allows relative displacement only in the aforementioned flexible direction between members connected to both sides thereof. Assume the case of an elastic hinge having flexible characteristics only in the X-axis direction and rigid characteristics in the Y-axis and Z-axis directions, and which allows relative displacement only in the X-axis direction between members connected to both sides thereof, when it is arranged along the Y-axis direction in the XY plane. In this case, for example, it is possible to move a movable member in the X-axis direction relative to a fixed-member with the elastic deformation of the elastic hinge. On the other hand, this elastic hinge hardly allows a relative movement in the Y-axis and Z-axis directions. In other words, the elastic hinge is made so that it can “guide” the movable member in the X-axis direction.
Furthermore, for example, when a rod-formed elastic hinge that has characteristics of being flexible in the bending direction and rigid in the axial direction is arranged with its axis coinciding with the Z-axis direction, a relative displacement within the XY
Kaneko Makoto
Morita Hiroshi
Nakamori Yasuhito
Sugimine Masanobu
Tomita Yoshiyuki
Arent & Fox PLLC
Guadalupe Yaritza
Sumitomo Heavy Industrie's, Ltd.
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