JPH10141942A - Shape measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the operating speed of the measuring system of a shape measuring instrument faster by reducing a mobile mass on a probe side and, at the same time, to reduce the weight of the device and make the device compact by reducing the size of a driving motor on a Z-axis driving section side. SOLUTION: A shape measuring instrument measures the shape of an object 7 by tracing the surface of the object 7 with the front end of a probe 24 by moving a mobile section 1 on the Y-axis side in the X-Y direction by driving an X-Y table 2 by means of an X-Y axis driving section 3 and, at the same time, by moving the slider section 20b side of a Z-axis mechanism 4 in the Z-axis direction by driving the slider section 20b side by means of a Z-axis driving section 6 while the slider section 20b side is compensated for gravity by means of a gravity compensating mechanism 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a shape measuring device for measuring the shape of an object to be measured.

[0002]

2. Description of the Related Art When three-dimensionally measuring the shape of an object such as an aspherical lens with a high accuracy of 0.1 to 0.01 μm, the surface shape of the object is measured using a shape measuring device. There are many. Such a shape measuring device generally includes an XY table in which a fixed portion is fixed to a pedestal or the like, and a movable portion is configured to be movable in the X-axis direction and the Y-axis direction.
An XY-axis drive unit that drives a table to move the movable unit of the XY table in the X-axis direction and the Y-axis direction, and a fixed unit is fixed on the movable unit of the XY table, and the movable unit is A Z-axis mechanism configured to be movable in the Z-axis direction;
A Z-axis drive section fixed on the fixed section of the axis mechanism and driving a movable section of the Z-axis mechanism to move the Z-axis mechanism in the Z-axis direction; and a Z-axis drive section fixed to the movable section of the Z-axis mechanism. It has a probe mechanism that measures the shape by tracing the surface,
While driving the XY table by the XY-axis drive unit to move the movable unit in the XY-axis direction, and driving the Z-axis mechanism by the Z-axis drive unit to move the movable unit in the Z-axis direction, The shape of the object is measured by tracing the surface of the object with the tip of the probe. In such a shape measuring device, when the Z-axis mechanism is driven by the Z-axis driving unit to move the movable unit in the Z-axis direction, the movable unit must be moved while supporting the weight of the movable unit. ,
The movable part of the Z-axis mechanism is urged upward by using any of gravity compensation mechanisms such as a method using a counterweight, a method using a spring, and a method using an air cylinder.

[0003]

However, such gravity compensation mechanisms using a method using a counterweight, a method using a spring, a method using an air cylinder, etc., have the following problems. there were. That is, in the gravity compensation mechanism using the counterweight, a counterweight having substantially the same weight as the movable portion of the Z-axis mechanism is prepared, and the counterweight and the movable portion of the Z-axis mechanism are connected by a wire. Since the pulley supports the wire, the rigidity of the movable part cannot be increased, and it is difficult to increase the responsiveness. In addition, in such a gravity compensation mechanism using a counterweight, not only is it difficult to operate smoothly due to the friction generated between the pulley and the wire, but also it is not possible to perform accurate positioning, and furthermore, the movable mass Is doubled, so that there is a problem that the driving force of the driving motor used as the Z-axis driving unit must be increased. Also, in the gravity compensation mechanism using a spring, when the movable part of the Z-axis mechanism shifts upward or downward from the position where the spring force and the gravity of the movable part are balanced, restoration is performed in proportion to the amount of the shift. Since the force is increased, it is difficult to accurately control the position of the movable section, and there is a problem that it is difficult to adjust the gain of the drive motor used as the Z-axis drive section. Also, in the gravity compensation mechanism using the air cylinder, when the stopping position of the movable part constituting the Z-axis mechanism is balanced, the air compressibility is considered in consideration of the responsiveness of the movable part and the balance of the movable part. There was a problem that the adjustment was difficult.

[0004] To solve these problems, Japanese Patent Application Laid-Open No. 2-134506 has proposed a "shape measuring apparatus". In this shape measuring apparatus, as shown in FIG.
02, a position detector 103 for detecting the vertical position of the Z moving unit 102 is provided. Based on the detection result of the position detector 103, a linear motor 104 is driven by a servo circuit 106 to determine the length of the spring 105. The linear motor 104 is driven even if the magnitude of the restoring force changes even if the restoring force changes from the vertical position where the Z moving unit 102 is balanced with the restoring force of the spring 105 and the magnitude of the restoring force changes. The force balances the weight of the Z moving unit 102 with the restoring force of the spring 105. However, in such a method, the linear motor 104 drives the Z moving unit 102 in the vertical direction and the spring 1
Since it is necessary to generate a thrust combined with the restoring force of the linear motor 05, a linear motor 104 capable of generating a large thrust must be used, and the control system becomes more complicated and the measurement operation is accelerated. There was a problem that it became difficult to do.

The present invention has been made in view of the above circumstances, and in the first aspect, a non-contact type gravity compensation independent of a Z-axis drive unit for driving a movable unit of a Z-axis mechanism in the Z-axis direction. By providing a mechanism, it is possible to reduce the movable mass and speed up the operation of the measuring system, and to reduce the size of the drive motor on the Z-axis drive unit side to achieve a reduction in the weight and size of the entire apparatus. It is an object of the present invention to provide a shape measuring device which can be used. According to the second aspect of the present invention, an air coupling is used as a coupling mechanism serving as a component of the gravity compensation mechanism, so that when the movable part of the Z-axis mechanism is driven by the drive motor on the gravity compensation mechanism side, the drive motor is used. An object of the present invention is to provide a shape measuring apparatus capable of improving measurement accuracy by preventing vibration, vibration due to friction between components constituting a gravity compensation mechanism, and the like from being transmitted to a movable portion of a Z-axis mechanism. . Claim 3
By connecting a ball screw mechanism, which is a component of the gravity compensation mechanism, to an air slide with an air coupling, a downward force acting on a movable portion of the Z-axis mechanism due to gravity is converted into a rotation direction, and the drive motor is driven. It is an object of the present invention to provide a shape measuring device which can easily perform the control of the above, and thereby can make the whole gravity compensation mechanism compact.

[0006]

To achieve the above object, according to the present invention, a probe is moved three-dimensionally along a surface of an object to be measured. In a shape measuring apparatus for measuring a shape, a fixed part side movable in a horizontal direction is arranged so as to be elongated in a vertical direction, and a movable part side supporting the probe side is guided by the fixed part side so as to be movable in a vertical direction. A gravitational compensation mechanism that urges the movable portion side upward without contact by a driving force obtained by a gravity compensation drive source to perform gravity compensation on the movable portion side, and a Z-axis drive. And a Z-axis drive mechanism for vertically moving the movable portion side in accordance with the surface height of the object to be measured by a driving force obtained by a source. According to a second aspect of the present invention, in the shape measuring device according to the first aspect, an air coupling is used as a coupling mechanism that transmits the driving force obtained by the gravity compensation driving source to the movable unit side in a non-contact manner. It is characterized by: According to a third aspect, in the shape measuring apparatus according to the first or second aspect,
A ball screw mechanism is used as an elevating mechanism for elevating and lowering the air coupling and the movable part side by a driving force obtained by the gravity compensation driving source.

According to the first aspect of the present invention, the non-contact type gravity compensation mechanism is provided independently of the Z-axis driving section for driving the movable section of the Z-axis mechanism in the Z-axis direction. As a result, the speed of the operation of the measurement system is increased, and the size of the drive motor on the Z-axis drive unit side is reduced, so that the entire device is reduced in weight and size. According to the second aspect of the present invention, an air coupling is used as a coupling mechanism serving as a component of the gravity compensation mechanism, so that when the movable part of the Z-axis mechanism is driven by the drive motor on the gravity compensation mechanism side, the drive motor is used. Vibration, vibration due to friction between components constituting the gravity compensation mechanism, and the like are not transmitted to the movable portion of the Z-axis mechanism to improve measurement accuracy. According to a third aspect of the present invention, a ball screw mechanism, which is a component of the gravity compensation mechanism, and an air slide are connected by an air coupling, thereby converting a downward force acting on a movable portion of the Z-axis mechanism by gravity into a rotation direction. This facilitates control of the drive motor, thereby making the entire gravity compensation mechanism compact.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 is a partially cut front view showing one embodiment of a shape measuring apparatus according to the present invention. In the shape measuring apparatus 1 shown in FIG.
The XY table 2 is fixed to the XY table 2 and is configured such that the Y-axis side movable portion 15 is movable in the X-axis direction and the Y-axis direction.
X that drives the Y table 2 to move the Y-axis side movable portion 15 of the XY table 2 in the X-axis direction and the Y-axis direction.
The Y-axis driving unit 3, the Z-axis substrate 18 and the side plate 19
A Z-axis mechanism 4 fixed to the Y-axis-side movable portion 15 of the Y-table 2 so that the slider portion 20b is movable in the Z-axis direction.
And a gravity compensation mechanism 5 fixed on the side plate 19 side of the Z-axis mechanism 4 to urge the slider portion 20b of the Z-axis mechanism 4 upward to compensate for gravity on the slider portion 20b side.
The Z-axis drive unit 6 fixed on the side plate 19 of the Z-axis mechanism 4 and driving the slider unit 20b of the Z-axis mechanism 4 to move the slider unit 20b in the Z-axis direction; and the slider unit 20b of the Z-axis mechanism 4 A probe mechanism 8 which is fixed and measures the shape of the object 7 by tracing the surface thereof;
Driving the Y-table 2 to move the Y-axis-side movable portion 15 in the XY-axis direction,
The Z-axis drive unit 6 drives the slider unit 20b side of the Z-axis mechanism 4 to move the slider unit 20b side in the Z-axis direction while compensating for the gravity of the slider unit 20b side of the shaft mechanism 4, and the measured object is measured by the probe 24 of the probe mechanism 8. The shape of the object 7 is measured by tracing the surface of the object 7.

The XY table 2 is formed of a plate-like member, and has an X-axis side fixing portion 10 fixed to a pedestal 9 by bolts, and a lower rail extending in the X-axis direction. A plurality of slide rails 11 mounted on the fixed portion 10; an X-axis side movable portion 12 formed of a plate-shaped member and mounted on an upper rail of each slide rail 11;
A Y-axis-side fixed portion 13 fixed to the axis-side movable portion 12, a plurality of slide rails 14 whose lower rails are mounted on the Y-axis-side fixed portion 13 in a direction longer in the Y-axis direction, and a plate-shaped member; And a Y-axis side movable section 15 mounted on the upper rail of each slide rail 14, and the X-axis side movable section 1 is driven by the driving force of the XY-axis drive section 3.
2. The Y-axis side movable section 15 is moved in the X-axis direction and the Y-axis direction, respectively. The XY-axis drive unit 3 is configured such that the housing side is fixed to the X-axis side fixing unit 10 and the drive shaft side is the X-axis side movable unit 12.
, And generates a driving force according to a driving voltage output from a control device (not shown) to move the driving shaft,
An X-axis drive motor 16 for moving the X-axis side movable section 12 in the X-axis direction; an enclosure side fixed to the Y-axis side fixed section 13 and a drive axis side fixed to the Y-axis side movable section 15; And a Y-axis driving motor 17 for generating a driving force according to the driving voltage to be moved and moving the driving shaft to move the Y-axis side movable portion 15 in the Y-axis direction. Is generated to drive the XY table 2 to set the XY coordinates of the Y-axis side movable portion 15 to the designated coordinate values.

Further, the Z-axis mechanism 4 is formed so as to be elongated in the Z-axis direction with a Z-axis substrate 18 constituted by an L-shaped plate-like member vertically suspended on the Y-axis side movable portion 15. Side plate 1 composed of a plate-like member and fixed to Z-axis substrate 18
9 and a rail portion 20a which is arranged at a predetermined distance from the Z-axis substrate 18 and is inserted through the rail portion 20a, held in a non-contact state with the rail portion 20a by air, and is movable in the Z-axis direction. An air slider 20 having a slider portion 20b formed on the upper surface of the air slider 20 and a side plate 19
And an upper support member 21 for fixing the lower end of the rail portion 20a constituting the air slider 20 to the lower end of the side plate 19.
The slider unit 20b is moved by the driving force generated by the gravity compensation mechanism 5 and the Z-axis driving unit 6 while being moved in the X-axis direction and the Y-axis direction along with the movement of the Y-axis side movable unit 15 of the Y table 2. Move in the Z-axis direction (vertical direction).

The probe mechanism 8 includes a measuring device 23 whose housing is fixed to the side surface of the slider portion 20b of the Z-axis mechanism 4.
And a probe 24 arranged so as to protrude from the lower surface of the measuring device 23 and having a tip facing the surface of the object 7 to be measured.
The tip of the probe 24 is moved in accordance with the Z coordinate value of the slider portion 20b, and the surface shape of the device 7 is measured by the measuring device 23 while tracing the surface of the device 7. The gravity compensation mechanism 5 includes a motor holder 25 fixed to the upper side of the rear surface of the side plate 19 and a drive shaft 2 fixed to the motor holder 25 in accordance with a driving voltage supplied from a control device.
6 and a micro-slip clutch / brake mechanism 28 using engineering plastics and fine chemicals. An inner ring 29 is fixed to the drive shaft 26 of the drive motor 27 as shown in FIG. As shown in FIG. 1, a spiral is formed on the surface of a nut part 32 in which a number of balls are arranged in an endless track formed therein,
It has a screw rod 33 into which the nut part 32 is screwed, and a ball screw mechanism 34 arranged so that the screw rod 33 is in the sliding direction (Z-axis direction) of the slider part 20b.

The gravity compensating mechanism 5 further includes an upper bearing 35 fixed to the upper surface of the side plate 19 while rotatably supporting the upper part of the screw rod 33 constituting the ball screw mechanism 34, and a screw rod 33. A lower bearing 36 fixed to the center of the surface of the side plate 19 while rotatably supporting the lower side;
As shown in FIG. 2, a timing pulley 37 fixed to the upper end of the threaded bar 33 and an outer ring of the timing pulley 37 and the torque keeper 31 inserted into an opening 39 formed on the upper side of the side plate 19. 30 and two members 40a which are connected to each other with air interposed therebetween as shown in FIGS.
40b, one member 40b is fixed to the nut portion 32, and the other member 40a is
0b fixed to the air coupling 40. When a drive voltage is supplied from the control device, a torque is generated by the drive motor 27, and the torque is used to drive the drive shaft 26, the inner ring 29 of the torque keeper 31,
The outer ring 30, the timing belt 38, and the timing pulley 37 of the torque keeper 31 are rotationally driven to rotate the screw rod 3.
3 is rotated to raise and lower the nut portion 32 screwed into the threaded rod 33, thereby urging the slider portion 20b connected to the nut portion 32 through the air coupling 40 upward. And the probe mechanism 8
Weight and gravity compensation.

The Z-axis drive section 6 has a housing fixed to the lower side of the back surface of the side plate 19 by screws 43, and the tip of the drive shaft 41 is connected to the slider section 20b through an opening 42 formed in the side plate 19. When the voice coil 44 is fixed to one end and the housing is fixed to the Z-axis substrate 18 and a measurement start signal is supplied from the control device, the slide shaft 45 is retracted, and the tip of the slide shaft 45 is driven. A drop prevention stopper 46 for the Z-axis, which is detached from the rear end of the shaft and opens the drive shaft 41 to make it freely movable in the vertical direction, when the measurement start signal is supplied from the control device. By operating the fall prevention stopper 46, the leading end of the slide shaft 45 is detached from the rear end of the drive shaft of the voice coil 44, and the drive shaft 41 is movable in the Z-axis direction. In this state,
The voice coil 44 is operated in accordance with the drive voltage supplied from the control device to urge the drive shaft 41 up and down,
The slider unit 20b, the measuring device 23, and the probe 24 connected to the drive shaft 41 are moved up and down.

Next, a partially cut front view shown in FIG.
The operation of this embodiment will be described with reference to enlarged cross-sectional views and top views of the main parts shown in FIGS. 3 (a) and 3 (b). First,
When measuring the surface shape of the device 7 to be measured, a torque is generated by the drive motor 27 of the gravity compensation mechanism 5 based on the drive voltage output from the control device, and the torque keeper 3 is driven.
1. The screw rod 33 of the ball screw mechanism 34 is rotationally driven via the timing belt 38 and the timing pulley 37, and the nut portion 32 is urged upward, whereby the nut portion 32 is connected to the nut portion 32 by the air coupling 40. The slider portion 20b, the measuring device 23, and the probe 24 are urged upward, and the slider portion 20b, the measuring device 2,
3. The probe 24 and the like are gravity compensated, and with a slight force,
It can be moved both upward and downward. After that, a measurement start signal is output from the control device,
The Z-axis drop prevention stopper 46 of the Z-axis drive unit 6 is operated, the tip of the slide shaft 45 is removed from the rear end of the drive shaft of the voice coil 44, and the drive shaft 41 is made movable in the Z-axis direction. You.

In this state, when the X-axis drive voltage, the Y-axis drive voltage, and the Z-axis drive voltage are output from the control device, the XY drive unit 3 drives the XY table 2. , The Y-axis side movable section 15 is driven in the X-axis direction or the Y-axis direction, the Z-axis mechanism 4 is moved in the X-axis direction or the Y-axis direction, and the voice coil 44 of the Z-axis drive section 6 causes the slider section 20b to move. Is driven upward or downward, the Z-axis coordinate of the measuring device 23 fixed to the slider portion 20b is adjusted, and the surface of the DUT 7 is traced by the probe 24 to measure the surface shape. At this time, the drive motor 27 of the gravity compensation mechanism 5 causes the slider portion 20b
Is urged upward by a force corresponding to the gravitational force. Therefore, when the slider portion 20b is driven upward or downward by the voice coil 44 of the Z-axis drive portion 6, either upward or downward The direction can be raised and lowered with the same driving force. Also, the slider portion 20b
When an excessive force is applied to the belt, the force is applied to the nut portion 32 → the screw rod 33 → the timing pulley 37 → the timing belt 3
8 → Transmitted to the outer ring 30 of the torque keeper 31,
Since the slipping clutch / brake mechanism 28 of the torque keeper 31 slips, it is possible to prevent an excessive force from being applied to the drive motor 27.

As described above, in this embodiment, the XY table 2 is driven by the XY-axis driving section 3 to move the Y-axis side movable section 15 in the XY-axis directions, and the Z-axis is moved by the gravity compensation mechanism 5. The Z-axis drive unit 6 drives the slider unit 20b side of the Z-axis mechanism 4 while gravity-compensating the slider unit 20b side of the axis mechanism 4, and moves the slider unit 20b in the Z-axis direction while measuring at the tip of the probe 34. Trace the surface of object 7,
Since the shape of the DUT 7 is measured, the voice coil 44 of the Z-axis drive unit 6 can be reduced in size to promote compactness and low thrust of the entire device. Also,
Independently of the Z-axis drive section 6 for driving the slider section 20b side of the Z-axis mechanism 4 in the Z-axis direction, a non-contact type gravity compensation mechanism 5
Is provided, the movable mass on the slider section 20b side is reduced, and the operation of the measurement system can be accelerated. In addition, the drive motor 27 on the gravity compensation mechanism 5 side is reduced, thereby reducing the weight of the entire apparatus. , Compactness can be achieved.

Further, since the air coupling 40 is used as a connecting mechanism as a component of the gravity compensating mechanism 5,
The Z-axis mechanism 4 is driven by the drive motor 27 on the gravity compensation mechanism 5 side.
When driving the slider portion 20b side, the drive motor 2
7, the torque keeper 31, the timing belt 38, the timing pulley 37 constituting the gravity compensation mechanism 5
Even if friction is generated between vibrations and the like, and vibration due to the friction is generated, the vibration is cut by the air coupling 40 so that the vibration is not transmitted to the slider portion 20b side of the Z-axis mechanism 4, thereby measuring Accuracy can be greatly improved. Further, since the ball screw mechanism 34, which is a component of the gravity compensation mechanism 5, and the air slider 20 are connected by the air coupling 40, a downward force acting on the slider portion 20b side of the Z-axis mechanism 4 due to gravity. Can be converted into a rotational direction to facilitate the control of the drive motor 27, thereby making the entire gravity compensation mechanism 5 compact. The drive motor 27 and the ball screw mechanism 34 are controlled by the torque keeper 31.
And the ball screw mechanism 34 can be easily driven with a constant torque, and when an excessive force is applied to the slider portion 20b side, the torque keeper 31 is caused to slip and the drive motor 27 Can be prevented from being subjected to excessive force. Furthermore, since the drive motor 27 and the torque keeper 31 constitute a torque motor of a continuous rated specification for continuously driving the ball screw mechanism 34 with a constant torque, the slider 2
The surface shape of the DUT 7 can be measured only by controlling the Z-axis drive unit 6 ignoring the gravity acting on the 0b side.

[0018]

As described above, according to the present invention, according to the first aspect, the Z-axis mechanism drives the movable portion of the Z-axis mechanism in the Z-axis direction.
By providing a non-contact type gravity compensation mechanism independent of the axis drive unit, it is possible to reduce the movable mass and speed up the operation of the measurement system, and to reduce the size of the drive motor on the Z-axis drive unit side. The overall weight and size can be reduced. According to the second aspect of the present invention, an air coupling is used as a coupling mechanism serving as a component of the gravity compensation mechanism, so that when the movable part of the Z-axis mechanism is driven by the drive motor on the gravity compensation mechanism side, the drive motor is used. Vibration, vibration due to friction between the components constituting the gravity compensation mechanism, and the like are not transmitted to the movable portion of the Z-axis mechanism, so that the measurement accuracy can be improved. According to a third aspect of the present invention, a ball screw mechanism, which is a component of the gravity compensation mechanism, and an air slide are connected by an air coupling, thereby converting a downward force acting on a movable portion of the Z-axis mechanism by gravity into a rotation direction. As a result, the drive motor can be easily controlled, whereby the entire gravity compensation mechanism can be made compact.

[Brief description of the drawings]

FIG. 1 is a partially cut front view showing one embodiment of a shape measuring apparatus according to the present invention.

FIG. 2 is an enlarged sectional view of a main part showing a detailed configuration example of a drive motor portion and a torque keeper portion shown in FIG.

FIG. 3 is an enlarged sectional view of a main part showing a detailed configuration example of an air coupling part shown in FIG. 1;

FIG. 4 is a top view showing a detailed configuration example of an air coupling part shown in FIG. 1;

FIG. 5 is a configuration diagram showing an example of a conventionally known shape measuring device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Shape measuring device, 2 ... XY table, 3 ... XY-axis drive part, 4 ... Z-axis mechanism, 5 ... Gravity compensation mechanism, 6 ... Z-axis drive part, 7 ... DUT, 8 ... Probe mechanism, 9 ... pedestal, 10
... X-axis fixed part, 11 ... Slide rail, 12 ... X-axis movable part, 13 ... Y-axis fixed part, 14 ... Slide rail,
15 ... Y-axis side movable part, 16 ... X-axis drive motor, 17 ... Y
Shaft drive motor, 18 ... Z-axis board, 19 ... side plate, 20a ...
Rail part (fixed part), 20b ... slider part (movable part),
Reference Signs List 20: air slider (air slide mechanism), 21: upper support member, 22: lower support member, 23: measuring device, 24
... probe, 25 ... motor holder, 26 ... drive shaft, 27
... drive motor (gravity compensation drive source), 28 ... slipping clutch / brake mechanism, 29 ... inner ring, 30 ...
Outer ring, 31 ... torque keeper, 32 ... nut part,
33: screw rod, 34: ball screw mechanism, 35: upper bearing, 36: lower bearing, 37: timing pulley, 38 ...
Timing belt, 39 ... opening, 40 ... air coupling, 40a ... member, 40b ... member, 41 ... drive shaft, 4
2: Opening, 43: Screw, 44: Voice coil (Z-axis drive source), 45: Slide shaft, 46: Fall prevention stopper for Z-axis

Claims (3)

[Claims] 1. A shape measuring apparatus for measuring a surface shape of an object to be measured while moving a probe in a three-dimensional direction along the surface of the object to be measured. An air slide mechanism that is disposed so as to be long and a movable section supporting the probe side is guided by the fixed section so as to be movable in a vertical direction; and a driving force obtained by a gravity compensation drive source, the movable section A gravity compensation mechanism for biasing the movable portion side upward without contacting the side thereof to compensate for the gravity of the movable portion side, and a driving force obtained by a Z-axis driving source, according to a surface height of the object to be measured, And a Z-axis drive mechanism for moving the movable section in the vertical direction. 2. The shape measuring apparatus according to claim 1, wherein an air coupling is used as a coupling mechanism for transmitting a driving force obtained by the gravity compensation driving source to the movable section in a non-contact manner. Characteristic shape measuring device. 3. The shape measuring device according to claim 1, wherein a ball screw mechanism is used as an elevating mechanism for elevating and lowering the air coupling and the movable part side by a driving force obtained by the gravity compensation driving source. A shape measuring apparatus characterized in that: