CN111702604A

CN111702604A - Shape measuring device and shape measuring method

Info

Publication number: CN111702604A
Application number: CN202010190997.7A
Authority: CN
Inventors: 高娜; 宫武勤
Original assignee: Sumitomo Heavy Industries Ltd
Current assignee: Sumitomo Heavy Industries Ltd
Priority date: 2019-03-18
Filing date: 2020-03-18
Publication date: 2020-09-25
Also published as: JP2020153705A; KR20200111116A; TW202040097A; TWI805905B; JP7212559B2

Abstract

The invention aims to reduce the influence of external temperature change and realize high-precision shape measurement. A shape measuring device (40) measures the surface shape of an object (W) to be measured by scanning three probes (41) arranged in a scanning direction in the scanning direction, wherein the three probes (41) are surrounded by a heat insulating member (43). By performing measurement in a state in which the three probes (41) are surrounded by the heat insulating material (43), even when the temperature characteristics of the probes (41) are different from each other, the influence of the change in the external temperature can be suppressed, and highly accurate shape measurement can be ensured.

Description

Shape measuring device and shape measuring method

The present application claims priority based on japanese patent application No. 2019-050154, applied 3/18/2019. The entire contents of this Japanese application are incorporated by reference into this specification.

Technical Field

The present invention relates to a shape measuring apparatus and a shape measuring method for measuring straightness.

Background

A shape measuring apparatus is known which obtains a surface shape of a measurement object by a sequential three-point method and measures a linear degree (for example, refer to patent document 1).

Patent document 1: japanese patent laid-open publication No. 2013-195082

In the above-described shape measuring device, for example, displacement in the emission direction of the detection light is detected by scanning using three light-emitting and light-receiving portions for the detection light.

In the above measurement, high resolution and high precision displacement detection are required, but the optical system of each light-emitting and light-receiving unit may be affected by a change in external temperature, which may result in a reduction in detection precision.

Disclosure of Invention

The invention aims to reduce the influence of external temperature change.

The present invention provides a shape measuring apparatus for measuring a surface shape of an object to be measured by scanning three probes arranged in a scanning direction in the scanning direction, wherein the three probes are surrounded by a heat insulating material or a heat insulating member.

The present invention also provides a shape measuring method for measuring a surface shape of an object to be measured by scanning three probes arranged in a scanning direction in the scanning direction, the shape measuring method being configured to perform measurement in a state where the three probes are surrounded by a heat insulating material or a heat insulating member.

According to the present invention, the influence of the change in the external temperature can be reduced.

Drawings

Fig. 1 is a perspective view showing a machine tool on which a shape measurement device according to an embodiment of the present invention is mounted.

Fig. 2 is a block diagram showing a control system of the machine tool.

Fig. 3 (a) is a perspective view of the head portion with the heat insulating member made of a heat insulating material removed, and fig. 3 (B) is a perspective view of the head portion with the heat insulating member.

Fig. 4 is a schematic view when scanning the surface of a workpiece.

Fig. 5 (a) and (B) are explanatory views for explaining the calculation of the distance to the surface of the workpiece and the curvature.

Fig. 6 is a cross-sectional view showing an example of the heat insulating member.

In the figure: 1-machine tool, 34-grinding device, 34 a-grinding wheel, 35-base, 36-table, 40-shape measuring device, 41-probe, 41a, 41b, 41 c-probe, 42-head, 421-jig, 43-heat insulating member, 43A-heat insulating structure, 60-control device, 63-grinding control section, 64-shape measuring processing section, 351-table feed motor, 332-grinding wheel head, 411-light source, 412-light receiving element, 413-optical fiber (light conducting member), W-workpiece (measuring object).

Detailed Description

Embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a perspective view showing a machine tool 1 on which a shape measuring device 40 according to an embodiment of the present invention is mounted, and fig. 2 is a block diagram showing a control system of the machine tool 1. In the figure, both the X-axis direction and the Y-axis direction are horizontal directions and orthogonal to each other, and the Z-axis direction is a vertical up-down direction orthogonal to the X-axis direction and the Y-axis direction.

[ outline of machine tool ]

The machine tool 1 is a so-called grinding machine that grinds one surface of a workpiece, and includes:

base portions

31a, 31 b; a first pillar 10; a second pillar 20; a cross rail 32; a saddle 331; a wheel head 332; a grinding device 34; a shape measuring device 40; a table 36 and a base 35 on which a workpiece as a measurement object is disposed; and a control device 60. The workpiece is a workpiece to be ground.

[ base ]

The base 35 includes a pair of linear guides, not shown, extending in the X-axis direction, and supports the table 36 to be movable in the X-axis direction. A conveying mechanism, not shown, for moving the table 36 in the X-axis direction is mounted on the base 35. The conveying mechanism can move the table 36 in the X-axis direction while holding the workpiece, using a table feed motor 351 (see fig. 2) capable of arbitrarily controlling the operation amount as a drive source.

The transport mechanism also functions as a scanning mechanism for moving three probes 41 described later relative to the workpiece W in a scanning direction (X-axis direction).

A pair of

base portions

31a and 31b are coupled and attached to both sides of the base 35 in the Y-axis direction so as to protrude from the base 35. The first support column 10 is placed and assembled on one base portion 31a, the second support column 20 is placed and assembled on the other base portion 31b, and the lower end portions of the

respective support columns

10 and 20 are fixed to the

base portions

31a and 31b by a known method such as bolts or welding.

[ first pillar and second pillar ]

The first support 10 and the second support 20 are vertically arranged in the Y-axis direction with the base 35 interposed therebetween. The cross rail 32 is fixedly supported at the upper end portions of the

columns

10 and 20 via a bracket 32a (the bracket on the second column 20 side is not shown) in a state facing the Y-axis direction. The upper end portions of the

respective pillars

10 and 20 are fixed to the cross rail 32 by a known method such as bolts or welding.

[ Cross guide ]

The lateral guide 32 is a member having a long dimension in the Y-axis direction, and on the front surface side thereof, the saddle 331 is supported movably in the Y-axis direction via a linear guide not shown.

A transport mechanism, not shown, for moving and positioning the saddle 331 in the Y-axis direction is mounted on the lateral guide rail 32. This transport mechanism uses a saddle feed motor 321 (see fig. 2) capable of arbitrarily controlling the operation amount as a drive source, and can freely move and position the saddle 331 in the Y-axis direction.

The saddle 331 supports the grinder head 332, and the grinder head 332 supports the grinding device 34. On the other hand, the movement control of the saddle 331 in the Y-axis direction by the saddle feed motor 321 of the cross rail 32 and the movement control of the workpiece in the X-axis direction by the table feed motor 351 of the base 35 are performed in cooperation. This enables the grinding wheel 34a of the grinding device 34 to be moved relative to the workpiece and positioned at an arbitrary position on the X-Y plane, thereby grinding the entire surface or an arbitrary position of the workpiece.

[ head and saddle of grinding wheel ]

The lateral guide rail 32 supports the grinding wheel head 332 movably in the Y-axis direction via a saddle 331, and the saddle 331 supports the grinding wheel head 332 vertically in the Z-axis direction. The grinding device 34 is supported by the lower end of the grinding wheel head 332.

The saddle 331 functions to raise and lower the wheel head 332 in the Z-axis direction.

Therefore, the saddle 331 supports the grinding wheel head 332 movably in the Z-axis direction by a linear guide not shown. A not-shown conveying mechanism that moves and positions the grinding wheel head 332 in the Z-axis direction is mounted on the saddle 331. The transport mechanism uses a wheel lifting motor 333 whose operation amount can be arbitrarily controlled as a drive source, and can move and position the wheel head 332 in the Z-axis direction at will.

[ grinding device ]

The grinding device 34 is supported by the lower end of the grinding wheel head 332.

The grinding device 34 includes a disc-shaped or cylindrical grinding wheel 34a rotationally driven around the Y axis and a grinding wheel rotating motor 341 for rotating the grinding wheel 34a as a tool. The grindstone 34a is disposed at the right end of the lower end portion of the grindstone head 332. The grinding wheel 34a is rotated by driving of the grinding wheel rotating motor 341, and the outer periphery of the grinding wheel 34a is thereby ground by sliding contact with the workpiece.

[ shape measuring apparatus ]

The shape measuring device 40 is a so-called spectral interferometer that measures the surface shape of the grinding surface of the workpiece ground by the grinding device 34 by a three-point method.

The shape measurement device 40 includes: the head 42 has three probes 41, three light sources 411, and three light receiving elements 412.

The probe 41 is connected to the light source 411 and the light receiving element 412 via an optical fiber 413 as a light transmitting member. That is, the light source 411 and the light receiving element 412 are provided separately from the probe 41 with the optical fiber 413 interposed therebetween.

The light source 411 is, for example, an SLD (Super Luminescent Diode) that outputs detection light of a plurality of predetermined wavelengths. The detection light is transmitted to the gauge head 41 through the optical fiber 413.

The probe 41 is a light-transmitting element that projects detection light from the light source 411 toward the workpiece from the output face facing the workpiece, and receives reflected light from the workpiece at the output face.

In the probe 41, interference light of detection light reflected by the output surface and reflected light from the workpiece is generated. The interference light is transmitted to the light receiving element 412 through the optical fiber 413.

The light receiving element 412 is, for example, a CCD, and receives the interference light from the probe 41 via a spectrometer, not shown. The spectroscope splits the light into a plurality of wavelengths of light set in advance, and the light receiving element 412 detects the light intensity of each wavelength of light and inputs the light intensity to the control device 60.

The probe 41 can detect the distance in the Z-axis direction from the output surface to the surface of the workpiece from the light intensity of each wavelength of the interference light.

Fig. 3 is a perspective view of the head part 42, in which (a) shows a state in which the heat insulating member 43 made of a heat insulating material is removed, and (B) shows a state in which the heat insulating member 43 is provided. The X-axis direction, the Y-axis direction, and the Z-axis direction in fig. 3 indicate directions in a state where the head 42 is attached to the grinding wheel head 332.

As shown in fig. 3, the head 42 includes: three probes 41; fixing jigs 414 that respectively clamp and hold the three probes 41; a jig 421 that integrally supports the three probes 41 via the fixing jigs 414; a support member 422 fixedly fitted to the jig 421; a base 423 for supporting each probe 41 via a support member 422; and an adsorption block 424 for attaching the base 423 to the surface of the grinding wheel head 332.

The jig 421 is a long rectangular block, and the three probes 41 are embedded and mounted in the jig 421 in a state where their output surfaces are exposed through an opening provided in the bottom of the jig 421.

The long side direction of the jig 421 is parallel to the X-axis direction. The three probes 41 are arranged at equal intervals in the X-axis direction by the jig 421.

The jig 421 holds the three probes 41 such that the optical axes of the detection lights thereof are all parallel to the Z-axis direction.

Thereby, the three probes 41 can perform distance detection in the Z-axis direction.

The clamp 421 is made of a metal material such as Invar (registered trademark) having a very small thermal expansion coefficient. This suppresses the relative positional variation of the distance between the probes 41 and the output surface due to the ambient temperature.

The support member 422 is a trapezoidal plate-like member, and is fixed and coupled to the clamp 421 by means of bolts, screws, or the like. The support member 422 can be detached from the jig 421.

The base 423 includes a flat plate-like base extending along the X-Y plane and two arms depending from the base, and the support member 422 is coupled to lower end portions of the arms.

The base 423 can adjust the angle of the support member 422 around the Y axis by means of a screw, a long hole, not shown, or the like. By this angle adjustment, the jig 421 can be rotated via the support member 422, and the direction of the optical axis of the detection light of each gauge 41 and the height of the output surface of each gauge 41 in the Z-axis direction can be adjusted.

Each attracting block 424 has a permanent magnet mounted therein, and the presence or absence of the attraction force of the permanent magnet can be switched by rotating a knob provided on the outside.

That is, the head 42 is detachable from the machine tool 1, and the head 42 can be attached to an appropriate position on the surface of the grinding wheel head 332 or the like by the respective suction blocks 424.

When the head 42 is attached to each suction block 424, the jig 421 and each gauge head 41 are appropriately oriented and arranged, and the angle between the base 423 and the support member 422 is adjusted to more accurately adjust the angle.

The three probes 41 of the head 42, the fixing jig 414, and the jig 421 are provided with an adiabatic structure.

Specifically, as shown in fig. 3 (B), the three probes 41, the fixing jig 414, and the jig 421 are surrounded by the heat insulating member 43.

The heat insulating member 43 covers the entire surfaces of the three probes 41, the fixing jig 414, and the clamp 421 (except for the portions of the probes 41 connected to the optical fibers). An opening 431 through which the detection light is emitted or the reflected light is incident is formed on the light-emitting side of the output surface of each probe 41 of the heat insulating member 43.

As shown in fig. 3 (B), the heat insulating member 43 may have a recess into which the three probes 41 and the jig 421 are fitted, formed inside the block-shaped heat insulating member 43, and the three probes 41 and the jig 421 may be accommodated in the recess, or the entire surfaces of the three probes 41 and the jig 421 may be covered with one heat insulating member 43 in a sheet shape. In this case, since a space is formed between the three probes 41, the measurement environments between the probes 41 in the same space are averaged, and variations between the probes 41 are reduced.

Further, a foaming heat insulating material may be sprayed on the surfaces of the three probes 41 and the jig 421. In this case, the probe 41 can be easily covered with the heat insulating material.

Further, although not shown, the probe 41 may be individually wrapped with a heat insulating material or a heat insulating member. However, in this case, it is preferable to perform measurement after correcting the deviation of the sensor itself.

As the heat insulating material covering each probe 41, a material called a heat insulating material such as a fiber-based heat insulating material (i.e., glass fiber, cellulose fiber, carbonized cork, wool heat insulating material, etc.) or a foam-based heat insulating material (i.e., urethane foam, phenol foam, polystyrene foam, etc.) is preferably used, but not limited thereto. For example, another heat insulating material having a thermal conductivity of 5.0[ W/mk ] or less, preferably 1.0[ W/mk ] or less, and more preferably 0.5[ W/mk ] or less may be used.

The heat insulating member 43 insulates the three probes 41, the fixing jig 414, and the jig 421 from the outside air, and thus reduces the influence of the outside ambient temperature.

[ control device ]

The controller 60 is a device for centrally controlling the entire machine tool 1, and is, for example, a computer including a CPU (central processing Unit), a RAM (Random Access Memory), a ROM (read only Memory), and other nonvolatile memories.

As shown in fig. 2, the control device 60 is electrically connected to the table feed motor 351, the saddle feed motor 321, the grinding wheel lift motor 333, and the grinding wheel rotating motor 341, and can control the drive thereof.

The control device 60 is connected to the shape measuring device 40, the display device 61, and the input device 62.

The display device 61 is a device for displaying various information, for example, a liquid crystal display or the like.

The input device 62 is an input interface for inputting various information and various commands to the machine tool 1.

The control device 60 includes a grinding control unit 63 and a shape measurement processing unit 64.

The control device 60 realizes the functions of the grinding control unit 63 and the shape measurement processing unit 64 by, for example, storing various programs corresponding to the functions of the grinding control unit 63 and the shape measurement processing unit 64 in the ROM and causing the CPU to execute the respective programs. Further, the grinding control unit 63 and the shape measurement processing unit 64 may be implemented by hardware by providing circuits separately.

The grinding control unit 63 controls the operation of the machine tool 1 during grinding of the workpiece.

For example, when various machining conditions such as the rotational speed, the grinding depth, and the grinding range of the grinding wheel are input in advance through the input device 62, the grinding control unit 63 controls the table feed motor 351, the saddle feed motor 321, the wheel lifting motor 333, and the wheel rotating motor 341 so as to perform grinding machining in accordance with the input machining conditions.

The shape measurement processing unit 64 performs the following processing: the surface shape of the workpiece is measured by the three-point method from detection outputs when the three probes 41 are scanned in the X-axis direction.

Fig. 4 is a schematic view of the case where the surface of the workpiece W is scanned, and (a) and (B) in fig. 5 are explanatory views for explaining calculation of the distance to the surface of the workpiece W and the curvature. In fig. 4 and 5, three probes 41 are denoted by 41a, 41b, and 41c in order from the upstream side in the scanning direction (the downstream side in the moving direction of the workpiece W).

Next, the content of the measurement method performed by the shape measurement processing unit 64 will be described with reference to fig. 4 to 5 (B).

As shown in fig. 4, the shape measurement processing unit 64 controls the table feed motor 351 to move the workpiece W in the X-axis direction at a predetermined speed when measuring the shape. In this state, the three probes 41 perform shape measurement at predetermined cycles, thereby scanning the surface of the workpiece W.

As shown in fig. 5 (a), the

probes

41a, 41b, and 41c are arranged in a row with a gap P therebetween in the X-axis direction. Which measures the distances in the Z-axis direction to the points a, b, and c on the surface of the workpiece W at this time.

When the distances in the Z-axis direction from the output faces of the

respective measuring heads

41a, 41b, and 41c to the surface of the workpiece W, which are obtained by the measuring

heads

41a, 41b, and 41c, are set to A, B, C, the distance in the Z-axis direction from the point b to the line segment ac (referred to as the gap g) can be obtained by the following equation (1).

g＝B-(A+C)/2…(1)

On the other hand, as shown in fig. 5 (B), the slope (dz) of the line segment ab may be used_abThe slope (dz) of the segment bc with respect to the/dx_bc/dx) and the second differential (d) of the displacement z at the point b on the surface of the workpiece W is expressed by the following equation (2)²z/dx²) (i.e., curvature (1/r) of point b)).

Slope of line ab (dz)_ab/dx) can be obtained from the following equation (3), and the slope (dz) of the line segment bc_bcThe value/dx) can be obtained from the following formula (4).

Therefore, by substituting the following expressions (3) and (4) into the above expression (2) and further substituting the expression (1), the following expression (5) can be obtained. Therefore, the second order differential of the displacement z (i.e., the curvature of the point b) can be obtained from the gap g and the intervals P between the

probes

41a, 41b, and 41 c.

Since the distance P between the

probes

41a, 41b, 41c is known, it can be stored in advance in the memory of the control device 60.

The shape measurement processing unit 64 acquires the distance A, B, C from the detection outputs of the

probes

41a, 41b, and 41c during scanning, and calculates the gap g according to equation (1). Next, the value of the interval P is read from the memory and the curvature is calculated according to equation (5). Next, the obtained curvature is second-order integrated at an integration pitch, and the displacement z at an arbitrary x point is obtained. The integration pitch is, for example, a data acquisition interval (scanning speed × sampling period) of each of the

probes

41a, 41b, and 41c in the X direction when scanning is performed.

[ operation of machine tool ]

The control device 60 drives the grinding wheel lifting motor 333 to a set grinding depth under the control of the grinding control unit 63, and drives the grinding wheel rotating motor 341 to set the rotation speed of the grinding wheel.

Then, the grinding wheel 34a of the grinding device 34 is ground while being relatively fed in the X-axis direction with respect to the workpiece by driving the table feed motor 351. Then, the grinding wheel 34a is moved in the Y-axis direction by a predetermined distance unit by driving the saddle feed motor 321, and grinding in the X-axis direction is repeated, thereby grinding the workpiece W within a predetermined grinding range.

Next, the controller 60 detects the curvature and flatness of the machined surface of the workpiece W after grinding.

That is, the head 42 is positioned with respect to the workpiece W by driving the table feed motor 351 and the saddle feed motor 321 so that the detection position of each probe 41 of the head 42 attached to the grinding wheel head 332 becomes the start position of the search range of the workpiece W. Then, the height of the output surface of each measuring head 41 is adjusted to a predetermined height by driving the wheel lifting motor 333.

Then, the workpiece W is moved at a predetermined speed by driving the table feed motor 351, and the probes 41 detect the distance A, B, C in the Z-axis direction at a predetermined sampling period with the X-axis direction as the scanning direction. Accordingly, the gap g is calculated over the entire length in the scanning direction within the grinding range.

Next, the grinding wheel 34a is moved in the Y-axis direction by a predetermined distance unit by driving the saddle feed motor 321, and the flatness of the entire grinding range is measured by obtaining the curvature and the displacement z over the entire grinding range in the X-axis direction.

[ technical effects of embodiments of the invention ]

The machine tool 1 includes a shape measuring device 40 that measures the surface shape (i.e., flatness) of a workpiece by scanning three probes 41 arranged in a line in an X-axis direction (scanning direction) in the scanning direction, and the three probes 41 of the shape measuring device 40 are surrounded by a heat insulating member 43.

Therefore, the three probes 41 are measured while being surrounded by the heat insulating member 43, and the influence of the ambient temperature change on each probe 41 can be reduced, and the curvature and the displacement can be detected with high accuracy.

Further, since the shape measuring apparatus 40 measures the surface shape of the workpiece W by the three-point method using the three probes 41, it is possible to cancel out the movement error or the undulation error of each probe 41 in the Z-axis direction, and it is possible to perform high-precision detection.

Even when the temperature characteristics of the probes 41 are different from each other, the heat insulating member 43 can reduce the influence of the ambient temperature on the probes 41, and thus can effectively suppress a decrease in detection accuracy.

Further, since the heat insulating member 43 also covers the jig 421 that integrally supports the three probes 41, the influence of the change in the ambient temperature on the jig 421 can be reduced, and detection can be performed with higher accuracy.

Further, since the heat insulating member 43 covers the support member 422 and the clamp 421, the cost can be reduced as compared with the case where the entire shape measuring apparatus 40 is covered. Further, since the base 423 is not covered with the heat insulating member 43, the support member 422 and the jig 421 can be connected to the base 423 after being covered with the heat insulating member 43, and therefore, the heat insulating member 43 can be provided more easily than in the case where the entire shape measuring apparatus 40 is covered with the covering member 43.

Further, since the machine tool 1 includes a conveyance mechanism that moves the three probes 41 relative to the workpiece W in the scanning direction by driving the table feed motor 351, scanning of the three probes 41 in the three-point method can be performed satisfactorily.

Further, since each of the three probes 41 is configured such that the light source 411 is isolated from the outside of the heat insulating member 43 via the optical fiber 413, even when the light source 411 generates heat, the influence of the temperature in the heat insulating member 43 can be sufficiently reduced, and highly accurate detection can be performed.

[ others ]

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. For example, although a grinding machine is illustrated as the machine tool 1, the shape measuring device 40 may be mounted on another machine tool for measuring the surface shape of the workpiece W after machining. For example, the shape measuring device 40 may be mounted on a cutting machine or the like.

For example, as shown in fig. 6, three probes 41, a fixing jig 414, and a jig 421 may be surrounded by an insulating structure 43A formed of a plurality of insulating members.

For example, the heat insulating structure 43A has a double-layer structure including a heat insulating member (i.e., the inner layer 432A) accommodating the three probes 41, the fixing jig 414, and the jig 421, and a heat insulating member (i.e., the outer layer 433A) accommodating the entire inner layer 432A inside, and is configured to have a vacuum heat insulating structure by performing vacuum processing in a hollow region between the inner layer 432A and the outer layer 433A. In this case, it is also preferable to provide an opening 431A through which the detection light and the reflected light pass on the output surface side of each of the probes 41.

In this case, by providing a vacuum layer between the inner layer 432A and the outer layer 433A, heat insulation from the outside can be effectively achieved.

Further, even if the inner layer 432A and the outer layer 433A are not formed of a heat insulating material, a heat insulating effect can be obtained. Therefore, for example, the inner layer 432A and the outer layer 433A can be formed of a metal material which is easily processed and has strength.

In these cases, the influence of the ambient temperature change on the three probes 41 can be reduced by the heat insulating structure 43A, and the curvature and displacement can be detected with high accuracy.

In the head 42, the clamp 421 is connected to the support member 422 in direct contact with the head, but a heat insulating material may be disposed between the head and the support member to suppress heat transfer.

The optical fiber 413 connecting each of the probe 41, the light source 411, and the light receiving element 412 may be surrounded by a heat insulator or the like to insulate the surroundings.

Claims

1. A shape measuring apparatus for measuring a surface shape of an object to be measured by scanning three probes arranged in a scanning direction in the scanning direction,

the three probes are surrounded by a thermally insulating material or member.

2. The shape measuring apparatus according to claim 1,

the surface shape of the object to be measured is measured by a three-point method using the three probes.

3. The shape measuring apparatus according to claim 1 or 2,

further comprises a jig for integrally supporting the three probes,

the three probes and the jig are surrounded by the heat insulating material or the heat insulating member.

4. The shape determining apparatus according to any one of claims 1 to 3,

the three probes are covered by one heat insulating member.

5. The shape determining apparatus according to any one of claims 1 to 4,

the scanning mechanism moves the three probes relative to the object to be measured in the scanning direction.

6. The shape determining apparatus according to any one of claims 1 to 5,

the three probes are each provided such that the light source thereof is isolated from the outside of the heat insulating material or the heat insulating member via a light conducting member.

7. A shape measuring method for measuring a surface shape of an object to be measured by scanning three probes arranged in a scanning direction in the scanning direction, the shape measuring method comprising,

the measurement is performed in a state where the three probes are surrounded by the heat insulating material or the heat insulating member.