JP4195608B2 - 2D measuring machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a two-dimensional measuring machine used for inspecting the size and shape of a flat object to be measured such as glass of a liquid crystal panel.
[0002]
[Prior art]
Conventionally, as a two-dimensional measuring machine of this type, as shown in FIG. 6, a surface plate 101 provided with a pair of parallel Y-axis guides 100 and an object W to be measured provided on the upper surface of the surface plate 101 are mounted. A horizontal table 102 to be placed, an X-axis beam 104 which is supported on each Y-axis guide 100 of the surface plate 101 via a Y-axis slider 103 and is movable in the Y-axis direction, and the X-axis beam An X-axis slider 105 supported by 104 and movable in the X-axis direction, a measurement head 106 supported on the front surface of the X-axis slider 105 and measuring the object W to be measured on the table 102, and the X-axis beam 104 and a scale 107 for measuring the movement distance in the Y-axis direction y. By operating the X-axis driving means and the Y-axis driving means 108, the X-axis slider 105 is moved in the X-axis direction. A head moving type two-dimensional measuring machine M is known in which the axial beam 104 is moved in the Y-axis direction y and the measurement head 106 is attached to a predetermined measurement position of the object W to be detected on the table 102 to perform measurement. (For example, see Patent Document 1 and Patent Document 2).
[0003]
[Patent Document 1]
Japanese Patent Publication No. 2-501330 [Patent Document 2]
Japanese Patent Laid-Open No. 7-12512 [0004]
[Problems to be solved by the invention]
However, in the conventional head moving type two-dimensional measuring machine M, the position of the support guide part of the Y-axis guide 100 and the Y-axis slider 103, the position of the upper surface (measurement surface) of the object W to be measured, At least two positions of the measurement surface position of the scale 107 and the drive position of the X-axis beam 104 by the Y-axis drive means 108 are different in the Z-axis direction z, and the center of gravity of the measurement head 106 is in the Y-axis direction y. The position S1 of the X-axis beam 104 by the Y-axis drive means 108 is separated from the position of the drive connecting portion of the X-axis beam 104 by the Y-axis driving means 108 (the position of the center line of the X-axis beam 104) So by a distance H. Therefore, when the X-axis beam 104 moves in the Y-axis direction y, the processing accuracy of the support guide portion between the Y-axis guide 100 and the Y-axis slider 103, and Y The pitching motion in the Y-axis direction y and the yawing motion in the X-axis direction are performed with the influence of the fluctuation of the driving force of the driving means, and the X-axis beam 104 swings by, for example, the angle θ in the Y-axis direction y. Then, the measurement head 106 generates a measurement error based on a large displacement ΔH1 in the Y-axis direction y, and there is a problem that it is difficult to improve the measurement accuracy by the measurement head 106. In particular, the movement of the X-axis beam 104 may become unstable due to the influence of pitching by the support guide portion between the Y-axis guide 100 and the Y-axis slider 103, and the measurement accuracy is more difficult to improve.
[0005]
The present invention has been made in view of the above circumstances, and can accurately measure the size and shape of the object to be measured while minimizing the influence of the guide error in the guide unit that moves the measuring head relative to the object to be inspected. It is an object to provide a two-dimensional measuring machine that can be used.
[0006]
[Means for Solving the Problems]
The present invention is characterized by the following points in order to solve the above problems.
That is, the two-dimensional measuring machine according to claim 1 includes a surface plate provided with Y-axis guides at both ends, a horizontal table provided on the surface of the surface plate on which the object to be measured is placed, and the surface plate. An X-axis beam supported by each Y-axis guide via a Y-axis slider and movable in the Y-axis direction provided along the X-axis direction above the table, and supported by the X-axis beam. An X-axis slider movable in the X-axis direction, a measurement head supported by the X-axis slider for measuring an object to be measured on the table, and a scale for measuring a movement distance of the X-axis beam in the Y-axis direction In the two-dimensional measuring machine, the support surface for supporting the Y-axis slider of the Y-axis guide, the measurement surface of the object to be measured on the table, and the detection surface of the Y-axis scale are arranged on the table. It is provided on parallel identical plane It is characterized by a door.
[0007]
A two-dimensional measuring machine according to claim 2 is the two-dimensional measuring machine according to claim 1, wherein the Y-axis driving means for moving the X-axis beam in the Y-axis direction is a Y-axis slider of the Y-axis guide. Is driven and connected to the Y-axis slider at a position in the vicinity of the support surface for supporting the slider.
[0008]
The coordinate measuring machine according to claim 3 is the coordinate measuring machine according to claim 1 or 2, wherein the X-axis slider is supported by the X-axis beam through an air bearing. Yes.
[0009]
The coordinate measuring machine according to claim 4 is the coordinate measuring machine according to any one of claims 1 to 3, wherein the X-axis slider has an X-axis direction centered at the center in the X-axis direction. A counterweight is provided that moves synchronously by an equal distance in a direction opposite to the moving direction in the X-axis direction of the axis slider.
[0010]
Further, the two-dimensional measuring machine according to claim 5 is the two-dimensional measuring machine according to claim 4, wherein the counterweight is placed on a guide rail spanning the Y-axis slider between the Y-axis sliders in the X-axis direction. And is connected to the X-axis slider by an endless cord-like member wound around a plurality of pulleys disposed on at least one of the X-axis beam and a member that moves together with the X-axis beam. It is characterized by being.
[0011]
A two-dimensional measuring machine according to a sixth aspect is the two-dimensional measuring machine according to the fourth aspect, wherein the counterweight is driven by a moving means different from the X-axis slider.
[0012]
A two-dimensional measuring machine according to a seventh aspect is the two-dimensional measuring machine according to any one of the fourth to sixth aspects, wherein the counterweight is supported by an illuminator guide fixed to the Y-axis slider. A plurality of transmissive illuminators, which are arranged at the bottom of the table and move in the X-axis direction so as to coincide with the movement position of the X-axis slider in the X-axis direction, are supported by the illuminator guide or a member that moves together with the illuminator guide. It is characterized by being connected by an endless cord-like member wound around the pulley.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a two-dimensional measuring machine according to an embodiment of the present invention will be described with reference to FIGS.
1 to 4, reference numeral 1 denotes a two-dimensional measuring machine according to an embodiment of the present invention. The two-dimensional measuring machine 1 is fixed on a gantry 2 and has a surface plate 4 provided with a pair of parallel Y-axis guides 3 and 3 horizontally along the Y-axis direction y at both ends, and the surface plate 4. Is supported by the Y-axis guides 3, 3 of the surface plate 4 via Y-axis sliders 6, 6. An X-axis beam 7 movable in the Y-axis direction y provided along the X-axis direction x perpendicular to the Y-axis direction y above the table 5 and the X-axis direction supported by the X-axis beam 7 an X-axis slider 8 that is movable in x, a measurement head 9 that is supported by the X-axis slider 8 and that measures the object W to be measured on the table 5, and a movement distance in the Y-axis direction y of the X-axis beam 7 Y-axis scale 10 as a standard scale for measuring the X-axis, and the Y-axis drive for moving the X-axis beam 7 in the Y-axis direction y And it means 11, and an X-axis driving means 12 for moving the measurement head 9 via the X-axis slider 8 in the X axis direction x.
[0014]
The table 5 is made of a transparent glass plate fixed to a rectangular frame plate whose front and rear end portions are fixed to the surface plate 4 via support pieces 5a, 5a. The upper surface (surface to be measured) Wa of the object W placed on the surface and the upper surfaces (support surfaces) 3a and 3a of the Y-axis guides 3 and 3 of the surface plate 4 are set to be on the same horizontal plane L. ing. Between the lower surface of the table 5 and the upper surface of the surface plate 4, a space E that is open on the side (outside in the X-axis direction x) is provided.
Each Y-axis slider 6 includes a main body portion 6a parallel to the upper surface 3a of the Y-axis guide 3, and a side wall portion 6b parallel to the inner surface 3b perpendicular to the upper surface 3a inside each Y-axis guide 3. A horizontal air bearing 13a for supporting the Y-axis slider 6 is provided between the main body 6a and the upper surface 3a of the Y-axis guide 3, and the side wall 6b and the inner surface of the Y-axis guide 3 A vertical air bearing 13b that restrains the movement of the Y-axis slider 6 in the X-axis direction is provided between 3b and 3b. These air bearings 13a and 13b include an air supply pad fixed to the main body portion 3a and the side wall portion 3b, and an upper surface 3a of the Y-axis guide 3 that forms a pressure receiving surface that receives air ejected from the air supply pad. It has a known structure consisting of an inner side surface 3b.
[0015]
The X-axis slider 8 has a frame shape in side view so as to surround the X-axis beam 7 having a rectangular cross section, and the rectangular shape of the X-axis slider 8 and the upper and lower surfaces and front and rear surfaces of the X-axis slider 8. An air bearing (not shown) having the same configuration as the air bearings 13a and 13b is provided between the inner peripheral surface of the shape and the X-axis slider 8 for guiding and moving in the X-axis direction.
The measuring head 9 has a CCD camera 9b attached to a microscope 9a, and is supported on the front surface of the X-axis slider 8 via a support member 9c. The microscope 9a is provided along the Z-axis direction z (direction perpendicular to the upper surface Wa of the object W to be measured) whose optical axis C is perpendicular to the X-axis direction x and the Y-axis direction y. The distance can be adjusted to match the upper surface Wa of the workpiece W.
[0016]
The Y-axis scale 10 includes a glass standard scale member having a scale on the surface to be detected between a pair of air bearings 13a and 13a provided on the upper surface 3a of the Y-axis guide 3 in the Y-axis direction. The scale of the standard scale member is measured with a detector fixed along the y axis and fixed to the Y axis slider 6 to detect the position data of the movement position of the Y axis slider 6. It can be seen as a kind of encoder.
The Y-axis driving unit 11 includes a linear motor magnet 11a in which a plurality of pairs of magnets opposed to each other with a predetermined interval are arranged over almost the entire length of the outer side of the Y-axis guide 3, and the outer side of the Y-axis slider. It is comprised as a Y-axis linear motor provided with the linear motor coil 11b fixed to the part and inserted between the pair of magnets of the linear motor magnet 11a.
The X-axis drive means 12 has the same basic configuration as the Y-axis linear motor, and is fixed to a magnet base 12a that is fixed to both ends of the Y-axis sliders 6 and 6 and spanned between them. An X-axis linear motor comprising a linear motor magnet 12b provided along the X-axis direction x and a linear motor coil 12c fixed to the X-axis slider 8 and inserted between the linear motor magnets 12b and 12b. Has been.
[0017]
Further, a weight guide (guide rail) 14 is stretched around the Y-axis sliders 6 and 6 along the X-axis direction x, and the measurement head 9 and the X-axis slider 8 are fixed to the weight guide 14. A counterweight 15 having a weight substantially equal to the total weight of is supported so as to be movable in the X-axis direction x. The counterweight 15 is provided below the endless wire ropes (cord-like members) 17 that are supported by four pulleys 16 on the upper and lower sides and the left and right sides that are rotatably supported by the X-axis beam 7 and the Y-axis slide 6. With respect to the X-axis slider 8 connected to the moving part by the connecting part 15a and connected to the moving part above the wire rope 17 by the connecting part 8a, the center of the table 5 in the X-axis direction x is the center. Thus, the X-axis slider 8 moves in synchronization with the same distance in the direction opposite to the moving direction in the X-axis direction x.
[0018]
In the space E below the table 5, an illuminator guide 19 is provided along the X-axis direction x, spanning between support members 18 and 18 fixed to the inner ends of the Y-axis sliders 6 and 6. The illuminator guide 19 supports a transmissive illuminator 20 movably in the X-axis direction x. The counterweight 15 is connected to a moving part above an endless wire rope 22 spanned by four pulleys 21 rotatably supported by the support members 18, 18. The counterweight 15 and the transmission illuminator 20 are connected to a moving portion below the wire rope 22 and move in opposite directions with respect to the X-axis direction x, and are always transmitted through the optical axis C of the microscope 9a of the measuring head 9. The moving positional relationship is maintained such that the centers of transmitted light of the illuminator 20 coincide.
The counterweight 15 is moved by an X-axis by a dedicated linear motor (a moving means different from the X-axis slider 8), instead of being moved through the wire rope 17 hung on the pulley 16 by the X-axis slider 8. It may be possible to move in the direction and move in synchronization with the direction opposite to the direction in which the X-axis slider 8 moves. Also in this case, the transmissive illuminator 20 moves in the direction opposite to the movement of the counterweight 15 in the X-axis direction x via the wire rope 22 spanned over the pulley 21, and thus the movement of the X-axis slider 8. And move in the same direction.
[0019]
Next, the operation of the coordinate measuring machine 1 according to the embodiment will be described.
Similar to the conventional two-dimensional measuring machine, the object to be measured W is placed on the table 5, and the transmitted light emitted from the transmission illuminator 20 from below the table 5 is received by the microscope 9 a of the measuring head 9. By operating the X-axis and Y-axis driving means 11 and 12, the X-axis slider 8 is moved in the X-axis direction, and the X-axis beam 7 is moved in the Y-axis direction y. Measurement is performed by attaching 9 to a predetermined measurement position of the object W to be detected on the table 5. The movement distance in the X and Y axis directions x and y of the measuring head 9 accompanying this measurement is detected by an X axis scale (not shown) provided between the X axis beam 7 and the X axis slider 8 and the Y axis scale 10. Based on these detection values and position data detected by the CCD camera through the microscope 9a, the position (size, shape) of a predetermined portion of the detected object W is measured.
[0020]
In the two-dimensional measuring machine 1 having the above-described configuration, particularly during the measurement, the X-axis beam 7 is supported to the Y-axis guide 3 of the surface plate 4 via the air bearings 13a and 13a. Pitching motion in the Y-axis direction y occurs in the X-axis beam 7 due to fluctuations in the driving force of the driving means 11, processing errors in the support guide portion between the Y-axis guide 3 and the Y-axis slider 6, and the influence thereof. As a result, the measurement head 9 is displaced in the Y-axis direction, and an error may occur in the measurement result of the position of the detection target W by the measurement head 9.
However, as described above, the upper surface 3a of the Y-axis guide 3, the detected surface with the scale of the Y-axis scale 10, and the upper surface Wa of the measured object W are positioned on the same plane L. As shown in FIG. 5, the center of gravity of the Y-axis slider 6 is brought closer to the position S1 of the microscope 9a by adding a weight by extending the microscope 9a side of the Y-axis slider 6. In addition, the distance H between the position So and the position S1 of the drive connecting portion of the X-axis beam 7 can be reduced, and the microscope 9a of the measuring head 9 is set at the inclination θ of the X-axis beam 7 due to the pitching motion. The displacement ΔH2 in the Y-axis direction y of the focal position (measurement position) can be made much smaller than the displacement ΔH1 in the conventional two-dimensional measuring machine, thereby measuring with a minimum measurement error. It is possible to improve the degree.
[0021]
A Y-axis driving means 11 for moving the X-axis beam 7 in the Y-axis direction y is linearly moved to the Y-axis slider 6 at a position near the support surface (upper surface 3a) of the Y-axis slider 6 in the Y-axis guide 3. Since it is drivingly connected via the motor coil 11b, the Y-axis driving means 11 suppresses the generation of a moment that tilts the X-axis beam 7 in the Y-axis direction y about the upper surface 3a of the Y-axis guide 3, Since the measurement head 9 is not displaced by the fall of the X-axis beam 7 in the Y-axis direction y, the measurement error of the position of the detected object W can be further reduced.
[0022]
Further, since the Y-axis slider 6 is supported by the Y-axis guide 3 via the air bearings 13a and 13b, the X-axis beam 7 is moved very smoothly in the Y-axis direction y. The air bearings 13a and 13b used for the support guide portion of the Y-axis slide 6 with respect to the Y-axis guide 3 (the guide portion for moving the X-axis beam 7 in the Y-axis direction y) move the X-axis beam 7. May cause an error in the measurement of the measuring head 9, but the upper surface 3 a of the Y-axis guide 3, the detected surface of the Y-axis scale 10, and the upper surface Wa of the detected object W as described above. By adopting a configuration positioned on substantially the same (including the same) plane L, the possibility of the measurement error is eliminated, and the position of the workpiece W can be measured with high accuracy.
[0023]
Further, the table 5 moves in the direction opposite to the moving direction in the X-axis direction x of the X-axis slider 8 around the center of the X-axis direction x in synchronization with the movement of the X-axis slider 8. The counterweight 15 is supported by a guide rail 14 spanning the Y-axis sliders 6 and 6 in the X-axis direction x, and moves along with the X-axis beam 7 and the X-axis beam 7. Since the endless wire rope 17 wound around a plurality of pulleys 16 disposed on the member is connected to the X-axis slider 8, the counterweight 15 is smoothly moved to move the X-axis slider 8. The X-axis beam 7 can be moved in synchronization with each other, and the weight acting on the X-axis beam 7 acts equally on the Y-axis sliders 6 and 6 at both ends of the X-axis beam 7. Thus, the driving force of the Y-axis driving means 11 for driving the Y-axis sliders 6 and 6 becomes the same, so that the yawing motion of the X-axis beam 7 can be suppressed, and the measurement error due to the influence of this yawing motion is reduced. And the structure is simple.
[0024]
Further, the counterweight 15 is supported by an illuminator guide 19 fixed to the Y-axis slider 6 and is arranged at the lower part of the table 5. The X-axis direction matches the movement position of the X-axis slider 8 in the X-axis direction x. The transmission illuminator 20 moving to x is connected by an endless wire rope 22 wound around a plurality of pulleys 21 supported by a member such as an illuminator guide 19 and a support member 18 that moves together with the illuminator guide 19. Therefore, by using the movement of the counterweight 15, the transmission illuminator 20 can be reliably moved in synchronization with the movement of the X-axis slider 8. Therefore, since a dedicated moving means for the counterweight 15 does not have to be provided, the structure is simplified.
When the counterweight 15 is provided with a dedicated moving means different from the X-axis slider 8 and is moved in the direction opposite to the movement direction of the X-axis slider 8 in synchronization with the movement of the X-axis slider 8. Unlike the moving means in which a transmission mechanism having a structure in which the wire rope 17 is wound around the pulley 16 is interposed, the counterweight 15 can be directly connected to the moving means and driven. The load on the slider 8 can be reduced.
[0025]
In the two-dimensional measuring machine according to the embodiment, a linear motor is used as the Y-axis driving means 11 for moving the X-axis beam 7 (X-axis slider 6) in the Y-axis direction y. Not limited to this, the ball nut is fixed to the X-axis slider 6, and the ball screw shaft screwed to the ball nut is rotated by an electric servo motor to move the X-axis slider 6 through the ball nut. Y-axis drive means can also be employed. In addition, the guide movement of the Y-axis slider 6 with respect to the Y-axis guide 3 and the guide movement of the X-axis slider 8 with respect to the X-axis beam 7 are performed via air bearings. It is also possible to perform the guide movement using a linear bearing having a rolling element interposed therebetween.
[0026]
【The invention's effect】
As described above, according to the present invention, the following excellent effects are obtained.
According to the two-dimensional measuring machine according to claim 1, the support surface of the Y-axis guide in the surface plate that supports the X-axis beam via the Y-axis slider, the measurement surface of the measurement object on the table, and the X-axis Since the detected surface of the Y-axis scale for measuring the moving distance of the beam in the Y-axis direction is provided on the same plane parallel to the table, fluctuations in the driving force of the Y-axis driving means, the Y-axis guide Even if a pitching motion in the Y-axis direction occurs in the X-axis beam due to a processing error of the support guide between the Y-axis slider and the Y-axis slider, the measurement head supported by the X-axis beam is greatly displaced in the Y-axis direction. Can be prevented, and the measurement error of the position of the object to be detected by the measuring head can be minimized.
[0027]
According to the two-dimensional measuring machine according to claim 2, the Y-axis driving means for moving the X-axis beam in the Y-axis direction is arranged on the Y-axis slider at a position in the vicinity of the support surface that supports the Y-axis slider of the Y-axis guide. Since the drive connection is made, generation of a moment for tilting the X-axis beam in the Y-axis direction by the Y-axis drive means can be suppressed, and the measurement error of the position of the detected object can be further reduced.
[0028]
According to the two-dimensional measuring machine according to claim 3, the X-axis slider is supported by the X-axis beam via the air bearing. In addition, since the Y-axis slider is supported by the Y-axis guide via the air bearing, the X-axis beam can be moved very smoothly in the Y-axis direction, and the X-axis beam can be moved in the Y-axis direction. Even if an air bearing that easily causes pitching or rolling is used in the guide part, a two-dimensional measuring machine that can improve the measurement accuracy can be realized.
[0029]
According to the coordinate measuring machine according to claim 4, the X-axis slider is synchronized with the X-axis slider at an equal distance in the direction opposite to the moving direction in the X-axis direction around the center of the table in the X-axis direction. Since the counterweights that move are connected, the weight acting on the X-axis beam acts equally on the X-axis sliders at both ends of the X-axis beam, and the Y-axis drive means for driving each Y-axis slider The driving force is the same, yawing motion of the X-axis beam can be suppressed, and measurement errors due to the influence of this yawing motion can be reduced.
[0030]
According to the two-dimensional measuring machine according to claim 5, the counterweight is supported on the guide rail that extends between the Y-axis sliders in the X-axis direction so as to be movable in the X-axis direction, and the X-axis beam and the X-axis are supported. Since the endless cord-like member wound around a plurality of pulleys disposed on at least one of the members moving with the beam is connected to the X-axis slider, the counterweight is used to move the X-axis slider. It can be moved smoothly and reliably in a synchronized manner, and the structure is simple.
[0031]
According to the two-dimensional measuring machine according to claim 6, since the counterweight is driven by a moving means different from the X-axis slider, a transmission mechanism having a structure in which a wire rope is wound around a pulley is interposed. Unlike the moving means, the counterweight can be driven by being directly connected to the moving means, so that the load on the X-axis slider can be reduced.
[0032]
According to the two-dimensional measuring machine of the seventh aspect, the counterweight is supported by the illuminator guide fixed to the Y-axis slider and is arranged at the lower part of the table so as to coincide with the movement position of the X-axis slider in the X-axis direction. Since the transmission illuminator that moves in the X-axis direction is connected by an endless cord-like member wound around a plurality of pulleys supported by the illuminator guide or a member that moves together with the illuminator guide, the counterweight By utilizing this movement, the transmission illuminator can be reliably moved in synchronization with the movement of the X-axis slider.
[Brief description of the drawings]
FIG. 1 is a front view showing a two-dimensional measuring machine according to an embodiment of the present invention.
FIG. 2 is a side view of the same.
FIG. 3 is a plan view of the same.
FIG. 4 is an enlarged rear view of the same.
FIG. 5 is an explanatory diagram showing a state of displacement in the Y-axis direction with respect to the object to be measured of the measuring instrument head of the coordinate measuring machine according to the embodiment of the present invention.
FIG. 6 is an explanatory diagram showing a state of displacement in the Y-axis direction with respect to an object to be measured of a measuring instrument head of a conventional two-dimensional measuring machine.
[Explanation of symbols]
1 Two-dimensional measuring machine 3 Y-axis guide 3a Upper surface (support surface)
4 Surface plate 5 Table 6 Y axis slider 7 X axis beam 8 X axis slider 9 Measuring head 10 Y axis scale 11 Y axis driving means 12 X axis driving means 13a, 13b Air bearing 14 Guide rail 15 Counterweight 16, 21 Pulley 17 , 22 Wire rope
19 illuminator guide 20 transmissive illuminator W object to be measured Wa upper surface (measurement surface)

Claims (7)

A surface plate provided with Y-axis guides on both ends, a horizontal table provided on the surface of the surface plate on which the object to be measured is placed, and supported on each Y-axis guide of the surface plate via a Y-axis slider And an X-axis beam which is provided along the X-axis direction above the table and is movable in the Y-axis direction, an X-axis slider supported by the X-axis beam and movable in the X-axis direction, In a two-dimensional measuring machine comprising a measuring head supported by an X-axis slider and measuring an object to be measured on the table, and a Y-axis scale for measuring a movement distance of the X-axis beam in the Y-axis direction,
The support surface for supporting the Y-axis slider of the Y-axis guide, the measurement surface of the object to be measured on the table, and the detection surface of the scale are provided on the same plane parallel to the table. A two-dimensional measuring machine characterized by that.   The Y-axis drive means for moving the X-axis beam in the Y-axis direction is drivingly connected to the Y-axis slider at a position near a support surface that supports the Y-axis slider of the Y-axis guide. Item 2. The two-dimensional measuring machine according to item 1. The two-dimensional measuring machine according to claim 1 or 2, wherein the X-axis slider is supported by the X-axis beam via an air bearing.   The X-axis slider is provided with a counterweight that moves synchronously by an equal distance in a direction opposite to the movement direction in the X-axis direction of the X-axis slider, centered on the center of the table in the X-axis direction. The two-dimensional measuring machine according to any one of claims 1 to 3.   The counterweight is supported by a guide rail that extends between the Y-axis sliders in the X-axis direction so as to be movable in the X-axis direction, and is disposed on at least one of the X-axis beam and the member that moves together with the X-axis beam. The two-dimensional measuring machine according to claim 4, wherein the two-dimensional measuring machine is connected to the X-axis slider by an endless cord-like member wound around a plurality of pulleys.   The two-dimensional measuring machine according to claim 4, wherein the counterweight is driven by a moving means different from the X-axis slider.   The counterweight is supported by an illuminator guide fixed to the Y-axis slider and is disposed below the table, and moves in the X-axis direction so as to coincide with the movement position of the X-axis slider in the X-axis direction. The illuminator is connected by an endless cord-like member wound around a plurality of pulleys supported by the illuminator guide or a member that moves together with the illuminator guide. The two-dimensional measuring machine described in Crab.

Images