JP2022132466A - Plane inspection device and plane inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plane inspection device, etc. with which it is possible to correct a deviation in height level of a test object on the basis of the measurement result of a liquid level.

SOLUTION: The present invention comprises a plurality of liquid level tools, a flow path pipe, and a correction device for correcting a deviation in height level of a test object on the basis of the detection result of a liquid level sensor. With a fluid circulating between level measurement containers through the flow path pipe, each of liquid levels obtained by the liquid level sensor when each liquid level tool is placed on a horizontal reference plane is defined as a reference level, and measurement is taken of a deviation in liquid level of each level measurement container with respect to the reference level, which is caused to occur by circulation of the fluid when the plurality of liquid level tools are installed at different top face positions of the test object. With the correction device, the liquid level of each level measurement container is controlled so as to approach the reference level, respectively, while a liquid level tool closest to the reference level is fixed in position not to move, and a deviation in height level of the test object is corrected.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a plane inspection apparatus and a plane inspection method.

A flatness measuring apparatus is known that measures the flatness of an object to be inspected using a measuring instrument. In the invention described in Patent Document 1, a plurality of fluid tanks are installed on the surface of an object to be inspected, and the liquid surface level of the fluid contained in the liquid tanks is measured using a height measuring device. The fluid tanks are connected by hoses so that the fluid can be circulated between the fluid tanks.

A height measuring device measures the liquid surface level of the fluid contained in each fluid tank, obtains the level difference, and calculates the flatness.

JP 2005-227081 A

However, in the invention described in Patent Document 1, although the flatness can be measured, there is no means for correcting the deviation of the height level of the object to be inspected.

As described above, in the invention described in Patent Document 1, although the flatness of an object to be inspected can be measured, the flatness cannot be corrected.

The present invention has been made in view of the above points, and in particular, a flat surface inspection apparatus and a flat surface inspection method capable of correcting deviations in the height level of an object to be inspected based on the measurement result of the liquid level. intended to provide

The present invention relates to a flatness inspection apparatus for inspecting the flatness of an object to be inspected, comprising a level measuring container capable of containing a fluid, and a liquid surface capable of measuring the liquid level of the fluid contained in the level measuring container. A plurality of liquid surface tools provided with sensors and installed at different positions on the upper surface of the object to be inspected are connected between the level measurement containers to enable the fluid to flow between the level measurement containers. and a correcting device for correcting a height level deviation of the object to be inspected based on the detection result of the liquid level sensor, wherein the fluid passes through the flow pipe to measure each level. The liquid level obtained by the liquid level sensor when each liquid level tool is placed on a horizontal reference plane is defined as a reference level, and the plurality of liquids is circulated between the containers. The deviation of the liquid level of each level measuring container from the reference level caused by the circulation of the fluid when the surface tool is installed at different positions on the upper surface of the object to be inspected is measured, and the correction device measures the While the liquid level tool closest to the reference level is fixed so as not to move, the liquid level of each level measuring container is controlled so as to approach each reference level, and the height level of the object to be inspected is controlled. It is characterized by correcting the deviation of

The present invention relates to a flatness inspection apparatus for inspecting the flatness of an object to be inspected, comprising a level measuring container capable of containing a fluid, and a liquid surface capable of measuring the liquid level of the fluid contained in the level measuring container. A plurality of liquid surface tools provided with sensors and installed at different positions on the upper surface of the object to be inspected are connected between the level measurement containers to enable the fluid to flow between the level measurement containers. and a correcting device for correcting a height level deviation of the object to be inspected based on the detection result of the liquid level sensor, wherein the fluid passes through the flow pipe to measure each level. The liquid level obtained by the liquid level sensor when each liquid level tool is placed on a horizontal reference plane is defined as a reference level, and the plurality of liquids is circulated between the containers. The deviation of the liquid level of each level measuring container from the reference level caused by the circulation of the fluid when the surface tool is installed at different positions on the upper surface of the object to be inspected is measured. A computing device for calculating a liquid level, and a height level at each measurement position of the device to be inspected, which is installed on the lower surface of the object to be inspected corresponding to each liquid level tool, based on the computation result of the computing device. and a plurality of elevating devices for correcting the deviation of the liquid surface, wherein the elevating device corresponding to the liquid surface tool whose liquid level is closest to the reference level is defined as a reference leg in the correction device. and driving the lifting devices other than the reference leg to control each liquid surface level to approach the reference level, thereby correcting the height level deviation of the object to be inspected.

In the present invention, the correction device detects whether or not the lifting device other than the reference leg is within a predetermined driving range when the lifting device other than the reference leg is moved up and down so as to approach the reference level. Preferably, the reference leg is moved up and down, and all the lifting devices other than the reference leg are controlled to move up and down within the predetermined drive range.

The present invention is a flatness inspection method for inspecting the flatness of an object to be inspected, wherein a plurality of lifting devices are arranged at different positions on the lower surface of the object to be inspected, and the object to be inspected corresponding to the lifting device is arranged. A step of installing, on an upper surface, a plurality of liquid level tools each having a level measuring container capable of containing a fluid and a liquid level sensor capable of measuring the level of the fluid contained in the level measuring container; The liquid level sensor detects the liquid level of the fluid contained in each of the level measurement containers connected by the , and the object to be inspected is raised and lowered by the lifting device based on the detection result of the liquid level sensor. while correcting the height level deviation at each measurement position of the object to be inspected, and the fluid circulates between each level measurement container through the flow pipe, and the horizontal reference The liquid level obtained by the liquid level sensor when each liquid level tool is placed on the surface is set as a reference level, and the plurality of liquid level tools are placed on different upper surfaces of the object to be inspected. The deviation of the level of each level-measuring vessel relative to the reference level caused by the circulation of the fluid when placed in position is measured, and the compensator moves the level tool closest to the reference level. wherein the liquid surface level of each level measuring container is controlled so as to approach each reference level while the liquid surface level of each level measuring container is fixed so as to correct the deviation of the height level of the object to be inspected. .

In the present invention, the step of placing the liquid surface tool on a horizontal reference plane and setting the liquid surface level to the reference level before installing the liquid surface tool on the upper surface of the object to be inspected; After installing the liquid surface tool on the upper surface of the object to be inspected, setting the lifting device corresponding to the liquid surface tool at the liquid surface level closest to the reference level as a reference leg; In the step of correcting the deviation of the height level, based on the detection result of the liquid level sensor, the lifting device other than the reference leg is moved up and down to control each liquid level to approach the reference level. is preferred.

In the present invention, in the step of correcting the deviation of the height level, it is detected whether or not the lifting device other than the reference leg is within a predetermined driving range when the lifting device is raised and lowered so as to approach the reference level. However, it is preferable that the reference leg is lifted/lowered when the reference leg is outside the predetermined drive range, and that all the lifting devices other than the reference leg are lifted/lowered within the predetermined drive range.

According to the flat surface inspection apparatus and the flat surface inspection method of the present invention, it is possible to correct the deviation of the height level of the object to be inspected based on the measurement result of the liquid level, measure and calculate the level deviation, and correct the level deviation. can be performed under automatic control.

1 is a schematic diagram of a plane inspection apparatus of the present embodiment; FIG. It is a schematic diagram which shows the relationship between the height of a leg, and a liquid surface level. 4 is a flow chart of a plane inspection method according to the present embodiment; It is a schematic diagram for demonstrating the liquid surface level of the initial conditions of experiment. FIG. 5A is a graph showing transition of each liquid surface level, and FIG. 5B is a graph showing transition of height level (%) of each leg.

An embodiment of the present invention (hereinafter abbreviated as "embodiment") will be described in detail below. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.

<Plane inspection device>
FIG. 1 is a schematic diagram of the plane inspection apparatus of this embodiment. A plane inspection apparatus 1 shown in FIG. 1 is an apparatus for inspecting the flatness of an object 2 to be inspected. Although the object 2 to be inspected is not particularly limited, it may be, for example, a floor.

As shown in FIG. 1 , the plane inspection apparatus 1 includes a liquid surface tool 3 , a flow channel tube 4 and a correction device 5 .

(Liquid surface tool 3)
The liquid level tool 3 comprises a level measuring container 6 and a liquid level sensor 7 . As shown in FIG. 1, the level measurement container 6 is, for example, a cylindrical container with a bottom, but it may have a shape capable of containing liquid. A liquid level sensor 7 is installed above the level measuring container 6 . The liquid level sensor 7 is, for example, a laser sensor, irradiates the liquid level with laser light from the liquid level sensor 7, and measures the liquid level from the reflected light. A float as a reflector may be floated on the liquid surface to measure the light reflected by the float. However, the use of the float tends to reduce the measurement accuracy of the liquid level, so the float is not used in this embodiment. is preferred.

As shown in FIG. 1, the plurality of liquid surface tools 3 are installed at different positions on the upper surface 2a of the object 2 to be inspected. In FIG. 1, four liquid surface tools 3 are installed at the four corners of the object 2 to be inspected. The installation location and number of the liquid surface tools 3 are not limited, and the installation location and number of the liquid surface tools 3 can be arbitrarily set according to the usage pattern of the inspection object 2 and the flatness required for the inspection object 2. can decide. By installing the liquid level tools 3 at the four corners of the object 2 to be inspected and measuring, the level deviation of the entire upper surface 2a of the object 2 to be inspected can be corrected with high accuracy.

(Flow pipe 4)
As shown in FIG. 1, each level measuring container 6 is connected by a channel pipe 4 . As a result, the liquid contained in each level measuring container 6 can flow between the level measuring containers 6 through the channel pipe 4 .

The flow pipe 4 is, for example, a flexible hose, although it is not particularly limited. Although the material of the hose is not particularly limited, it is preferably made of thermoplastic resin, and particularly preferably made of urethane.

(Correction device 5)
The correction device 5 corrects the height level deviation of the inspection object 2 based on the detection result of the liquid level sensor 7 . As described above, in this embodiment, not only is the height level deviation calculated, but also the height level deviation can be corrected. In particular, in this embodiment, by correcting the height level deviation at the measurement position of the liquid surface tool 3 (four corners of the object to be inspected 2 shown in FIG. 1) and repeating the level measurement and level correction by automatic control, , can be controlled so that each height level is approximately the same. As a result, the deviation of the height level of the object to be inspected 2 can be corrected with high precision.

Here, the “height level” refers to the height position of the upper surface 2a of the object 2 to be inspected. In this embodiment, when the height level of the upper surface 2a of the object to be inspected 2 is deviated, the deviation of the height level can be corrected. However, in this embodiment, the height level deviation is measured as the liquid level deviation. That is, in the present embodiment, the height level deviation of the inspection object 2 is corrected by correcting the liquid level deviation.

In this embodiment, the correction device 5 includes an arithmetic device 8 that calculates the liquid level of each liquid surface tool 3 and a plurality of lifting devices 9 arranged on the lower surface of the inspection object 2 corresponding to each liquid surface tool 3 . and

As shown in FIG. 1, the computing device 8 is electrically connected to the liquid level sensor 7 of each liquid level tool 3 . The computing device 8 calculates the liquid level of the liquid contained in each level measuring container 6 based on the detection signal from the liquid level sensor 7 .

As shown in FIG. 1, the lifting device 9 includes, for example, legs 10 that can be lifted and lowered, and a drive unit 11 . Leg 10 is, for example, a jack. A driving unit 11 such as a motor is connected to the leg 10 , and the leg 10 can be moved up and down by a predetermined amount according to the driving force of the driving unit 11 .

The computing device 8 calculates each liquid level and obtains the deviation of each liquid level. As will be described later, the deviation of the liquid level can be obtained as deviation from the reference level. Based on the deviation of the liquid level, the computing device 8 computes the lifting amount of the leg 10 of each lifting device 9 for correcting the level deviation. The calculation result of the calculation device 8 is sent to each drive unit 11, and each drive unit 11 corrects the deviation of the height level of the object to be inspected 2 while moving up and down each leg 10 based on the calculation result. .

Regarding the above-described level deviation correction, the leg 10 of the lifting device 9 corresponding to the liquid level tool 3 whose liquid level is closest to the reference level is defined as the reference leg. Then, the legs 10 other than the reference leg are raised and lowered to control each liquid level to approach the reference level.

As described above, in the present embodiment, a reference leg is determined, and with the reference leg fixed, the other leg 10 is moved up and down to perform level correction. If all the legs 10 are driven, it may be difficult to control the reference level. , the deviation of the height level of the object to be inspected 2 can be corrected easily and accurately.

Here, the "reference level" is the liquid level of the liquid level sensor 7 when each liquid level tool 3 is placed on a horizontal reference plane before the inspection, as will be described in detail in the plane inspection method described later. is defined as the “reference level”. In practice, the output value from the liquid level sensor 7 obtained at this time is used as the reference value. For example, reset the output value to zero.

Further, in the present embodiment, when the legs 10 other than the reference leg are raised and lowered so as to approach the reference level, it is detected whether or not they are within a predetermined driving range. Since the leg 10 has a limit of elevation and a limit of descent, it is preferable to provide a drive range inside the limit range of elevation (limit range > drive range) and drive the leg 10 within the drive range. It is possible to prevent a problem that hinders the lifting and lowering of 10.

When the leg 10 is out of the drive range, the reference leg is raised and lowered, and all the legs 10 other than the reference leg are controlled to be raised and lowered within the predetermined drive range.

Here, the raising and lowering of the leg will be described with reference to the drawings. For example, assume that the left leg 10a shown in FIG. 2 is the reference leg (hereinafter referred to as the reference leg 10a) and the right leg 10b in FIG. 2 is the driven leg. As shown in FIG. 2, the level measuring container 6a on the reference leg 10a and the level measuring container 6b on the leg 10b are connected by a channel pipe 4, and the fluid 12 contained in the level measuring container 6a is connected to the level measuring container 6b. , is larger than that of the level measuring container 6b. As a result, the liquid level L1 of the fluid 12 contained in the level measuring container 6a is higher than the liquid level L2 of the fluid 12 contained in the level measuring container 6b.

When the leg 10b is lowered from the state shown in FIG. As a result, the liquid level L2 of the fluid 12 in the level measuring container 6b rises from the initial state, and the liquid level L1 of the fluid 12 in the level measuring container a falls from the initial state.

Also, assume that the leg 10b exceeds the drive range when the leg 10b is driven to bring the liquid level L2 closer to the reference level. For example, it is assumed that the leg 10b shown in FIG. 2 exceeds the drive range.

At this time, the reference leg 10a is lifted from the state shown in FIG. As a result, the fluid 12 in the level measuring container 6a on the reference leg 10a flows through the channel pipe 4 to the level measuring container 6b on the leg 10b. As a result, the liquid level L2 of the fluid 12 contained in the level measuring container 6b becomes higher than in FIG. As a result, the leg 10b can be lowered in order to bring the liquid level L2 closer to the reference level, and the leg 10b can be kept within a predetermined driving range.

As described above, the flat surface inspection apparatus 1 of the present embodiment not only measures and calculates the deviation of the height level of the object to be inspected 2 (deviation of the liquid level), but also measures the height level at each measurement position. Misalignment can be corrected. Moreover, in the present embodiment, level deviation measurement/calculation and level deviation correction can be performed by automatic control.

<Plane inspection method>
Next, a planar inspection method for an object to be inspected according to the present embodiment will be described with reference to the flowchart of FIG.

In step ST1 shown in FIG. 3, first, as a preparatory step, a plurality of liquid surface tools 3 are placed on a horizontal reference plane. At this time, the liquid level tools 3 are connected by the channel pipe 4 as in FIG. 1, and the level measuring container 6 of each liquid level tool 3 contains the liquid. Therefore, the liquid can circulate between the level measuring containers 6 through the channel pipe 4 .

The liquid contained in the level measuring container 6 of each liquid level tool 3 has the same liquid level, and the liquid level at this time is referred to as the "reference level".

In step ST2 shown in FIG. 3, the liquid level of the liquid contained in each level measuring container 6 is measured by the liquid level sensor 7 installed above the liquid level. At this time, the liquid contained in the level measuring container 6 of each liquid level tool 3 is all at the same liquid level (reference level), and the output of each liquid level sensor 7 is the same. Use the reference value. For example, reset the output value to zero.

Next, in step ST3 shown in FIG. 3, as shown in FIG. 1, the lifting device 9 as the correction device 5 is arranged at the four corners of the lower surface 2b of the object 2 to be inspected. The lifting device 9 includes legs 10 and a driving section 11 . An object 2 to be inspected is placed on four legs 10 . Furthermore, the liquid surface tools 3 are installed at the four corners of the upper surface 2a of the object to be inspected 2 facing the leg 10 with the object to be inspected 2 interposed therebetween.

Next, in step ST4 shown in FIG. 3, the liquid level of the liquid contained in the level measuring container 6 of each liquid level tool 3 is measured by the liquid level sensor 7 . The output of the liquid level sensor 7 is sent to the computing device 8 . Based on the output of the liquid level sensor 7, the calculation device 8 sets the leg 10 under the liquid level tool 3, which has the closest output to the reference value (zero value) defined in step ST2, as the reference leg.

After that, the level deviation is corrected while driving the legs other than the reference leg. The level deviation correction below will be described with reference to experimental examples shown in FIGS. 4 and 5. FIG. Note that the numerical values of the experimental examples shown in FIGS. 4 and 5 are only examples. In addition, in the experimental example shown in FIG. 5, each leg is moved one by one, but actually, it is possible to move a plurality of legs at the same time.

FIG. 4 shows the initial state of each leg. As shown in FIG. 4, the leftmost leg A is defined as the reference leg A. As shown in FIG. Also, as shown in FIG. 4, for example, the height position of each leg A to D in the initial state is such that the height when the legs A to D are most contracted is 0%, and the height when they are most extended is 0%. If it is 100%, it is assumed to be at the 50% position in the middle.

Also, as shown in FIG. 4, it is assumed that the liquid surface level L1 of the fluid 12 contained in the level measuring container a on the reference leg A is at a position of 0 mm with respect to the reference level L0. That is, the liquid level L1 of the reference leg A matches the reference level L0 in the initial state. On the other hand, the liquid level L2 of the fluid 12 contained in the level measuring container b on the leg B is at a position higher than the reference level L0 by 0.8 mm. Further, the liquid surface level L3 of the fluid 12 contained in the level measuring container c on the leg C is at a position lower than the reference level L0 by 0.5 mm. Also, the liquid level L4 of the fluid 12 contained in the level measuring container d on the leg D is at a position lower than the reference level L0 by 0.3 mm.

In step ST5 in FIG. 3, the legs other than the reference leg are driven so that each liquid level approaches the reference level, that is, the output value obtained from the liquid level sensor approaches the reference value (zero value). , level deviation correction is executed (brought in).

Next, at step ST6 in FIG. 3, it is determined whether or not the legs other than the reference leg are within a predetermined drive range. In step ST6 of FIG. 3, for example, within 70% of the limit range of the leg is defined as the driving range.

If all legs are within the driving range, the process proceeds to step ST10. In step ST10, for example, it is determined whether or not the level deviation is within ±2.0%. In addition, the numerical value is just an example. This step can be determined from the output of the liquid level sensor 7 . That is, if the output value is within ±2.0% of the reference value, step ST10 is satisfied, and the plane inspection ends. On the other hand, if the level deviation exceeds ±2.0%, the process returns to step ST5 and the above steps are repeated.

On the other hand, when at least one leg is out of the driving range in step ST6 of FIG. 3, the process proceeds to step ST7. The steps from step ST5 to step ST10 will be described with reference to FIGS. 4 and 5. FIG. The horizontal axis of the graph shown in FIG. 5A indicates the number of times of driving, and the vertical axis indicates the deviation amount (mm) from the reference level. The horizontal axis of the graph shown in FIG. 5B indicates the number of times of driving, and the vertical axis indicates the leg height level (%). In the experimental example shown in FIG. 5, it is assumed that when a liquid level drops by 0.3 mm, the other liquid levels rise by 0.1 mm. In addition, it was assumed that moving only one leg and moving the liquid surface by 0.036 mm required moving 1% of the drive range. In the experiment, the leg farthest from the reference level L0 among the legs B to C was moved to the reference level.

In the first drive, the leg B located farthest from the reference level L0 was moved upward so as to match the reference level L0. As a result, the fluid 12 in the level measuring container b flows into the level measuring containers a, c, and d, and the liquid levels L1, L3, and L4 fluctuate (see FIG. 5A).

At this time, as shown in FIG. 5B, it was found that the driving range of leg B exceeded 70% or more. Therefore, leg B no longer satisfies the condition of step ST6 in FIG.

At step ST7 in FIG. 3, it is measured whether the leg B exceeding 70% is closer to the upper limit or the lower limit of the drive range. In the experimental example of FIG. 5, since leg B is close to the upper limit of the drive range, the process proceeds to step ST8.

At step ST8 in FIG. 3, the reference leg A is moved downward from the initial state in FIG. When the reference leg A is moved downward, the fluids in the level measurement containers b, c, and d flow into the level measurement container a. go down. Therefore, the liquid level L2 of the leg B is lowered from the reference level L0. Therefore, the leg B can be lowered in order to raise the liquid level L2 of the leg B. As a result, the leg B can be kept within the driving range of 70%.

In step ST7, if the leg that has exceeded the driving range is close to the lower limit, the process proceeds to step ST9 to raise the reference leg.

When all the legs other than the reference leg are within 70% of the drive range by driving the reference leg, the process proceeds to step ST10. Drive the legs other than the leg.

In this embodiment, each leg is driven little by little, and steps ST5 to ST10 are looped multiple times. As a result, as shown in FIG. 5A, the liquid level corresponding to each leg can be gradually brought closer to the reference level (0 mm).

According to the flat surface inspection apparatus and the flat surface inspection method of the present invention, it is possible to measure (calculate) the height level deviation of the object to be inspected and to correct the height level deviation under automatic control.

1: Plane inspection device 2: Object to be inspected 3: Liquid level tool 4: Flow channel 5: Correction device 6, a to d: Level measuring container 7: Liquid level sensor 8: Calculation device 9: Elevating device 10, A to D: leg 11: drive unit 12: fluid L0: reference level L1 to L4: liquid level

Claims (6)

A plane inspection apparatus for inspecting the flatness of an object to be inspected,
A plurality of level measuring containers capable of containing a fluid and a liquid level sensor capable of measuring the liquid level of the fluid contained in the level measuring container, which are installed at different positions on the upper surface of the object to be inspected. a liquid surface tool;
a channel pipe connected between each level measurement container and allowing the fluid to flow between each level measurement container;
a correction device that corrects a height level deviation of the object to be inspected based on the detection result of the liquid level sensor;
has
The fluid circulates between each level measurement container through the flow pipe,
The liquid level obtained by the liquid level sensor when each liquid level tool is placed on a horizontal reference plane is defined as a reference level,
measuring the deviation of the liquid level of each level measuring container from the reference level caused by the circulation of the fluid when the plurality of liquid level tools are installed at different positions on the upper surface of the object to be inspected;
In the correction device, the liquid level tool closest to the reference level is fixed so as not to move, and the liquid level of each level measuring container is controlled so as to approach each reference level. correcting the deviation of the height level of the object to be inspected,
A plane inspection device characterized by: A plane inspection apparatus for inspecting the flatness of an object to be inspected,
A plurality of level measuring containers capable of containing a fluid and a liquid level sensor capable of measuring the liquid level of the fluid contained in the level measuring container, which are installed at different positions on the upper surface of the object to be inspected. a liquid surface tool;
a channel pipe connected between each level measurement container and allowing the fluid to flow between each level measurement container;
a correction device that corrects a height level deviation of the object to be inspected based on the detection result of the liquid level sensor;
has
The fluid circulates between each level measurement container through the flow pipe,
The liquid level obtained by the liquid level sensor when each liquid level tool is placed on a horizontal reference plane is defined as a reference level,
measuring the deviation of the liquid level of each level measuring container from the reference level caused by the circulation of the fluid when the plurality of liquid level tools are installed at different positions on the upper surface of the object to be inspected;
The correction device is installed on the lower surface of the object to be inspected corresponding to each liquid level tool, and performs each measurement of the object to be inspected based on the calculation result of the arithmetic unit. a plurality of lifting devices for correcting height level deviations at positions,
In the correction device, the elevating device corresponding to the liquid level tool closest to the reference level is defined as a reference leg, and the elevating device other than the reference leg is driven to obtain each liquid level. is controlled so as to approach the reference level to correct deviation of the height level of the object to be inspected. In the correction device, when the lifting device other than the reference leg is moved up and down so as to approach the reference level, it is detected whether or not it is within a predetermined drive range. 3. The flat surface inspection apparatus according to claim 2, wherein all the lifting devices other than the reference leg are controlled to move up and down within the predetermined driving range. A plane inspection method for inspecting the flatness of an object to be inspected,
A plurality of elevating devices are arranged at different positions on the lower surface of the object to be inspected, and on the upper surface of the object to be inspected corresponding to the elevating devices, a level measuring container capable of containing a fluid and a level measuring container containing a fluid are provided. a step of installing a plurality of liquid level tools each having a liquid level sensor capable of measuring the liquid level of the fluid;
The liquid level sensor detects the liquid level of the fluid contained in each level measuring container connected by a channel pipe, and based on the detection result of the liquid level sensor, the object to be inspected is moved to the lifting device. a step of correcting a height level deviation at each measurement position of the object to be inspected while moving it up and down with the
The fluid circulates between each level measurement container through the flow pipe,
The liquid level obtained by the liquid level sensor when each liquid level tool is placed on a horizontal reference plane is defined as a reference level,
measuring the deviation of the liquid level of each level measuring container from the reference level caused by the circulation of the fluid when the plurality of liquid level tools are installed at different positions on the upper surface of the object to be inspected;
In the correction device, the liquid level tool closest to the reference level is fixed so as not to move, and the liquid level of each level measuring container is controlled so as to approach each reference level. correcting the deviation of the height level of the object to be inspected,
A plane inspection method characterized by: setting the liquid level to a reference level by placing the liquid level tool on a horizontal reference plane before installing the liquid level tool on the upper surface of the object to be inspected;
After installing the liquid surface tool on the upper surface of the object to be inspected, setting the lifting device corresponding to the liquid surface tool at the liquid surface level closest to the reference level as a reference leg;
In the step of correcting the deviation of the height level, based on the detection result of the liquid level sensor, the lifting device other than the reference leg is raised and lowered so that each liquid level approaches the reference level. 5. A plane inspection method according to claim 4, characterized in that: In the step of correcting the deviation of the height level, when the lifting device other than the reference leg is moved up and down so as to approach the reference level, it is detected whether or not it is within a predetermined driving range. 6. The plane according to claim 5, wherein the reference leg is moved up and down when the reference leg is outside the driving range of the plane, and all the lifting devices other than the reference leg are controlled to move up and down within the predetermined driving range. Inspection methods.

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