JP2003042750A - Three-dimensional shape measuring device with water tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a three-dimensional shape measuring device with a water tank capable of performing highly accurate shape measurement by suppressing deformations of an object to be measured due to temperature. SOLUTION: What is called a three-dimensional device for measuring the shape of the object to be measured by processing locational information from a probe location measuring means comprises a base for setting the object to be measured, a probe, and a trace mechanism for making the probe trace the surface of the object to be measured. The three-dimensional measuring device comprises the water tank, and the object to be measured is mounted in the water tank, and measured with the water tank filled with a liquid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional shape measuring apparatus for precisely measuring a curved surface shape of a lens, a mirror or the like with an error of, for example, 1 micrometer or less.

[0002]

2. Description of the Related Art Conventionally, a contact probe has been widely used as a three-dimensional coordinate measuring apparatus for three-dimensionally measuring the surface shape of an object to be measured.

FIG. 10 is a schematic view of a main part of a three-dimensional shape measuring apparatus for three-dimensionally measuring the shape of a DUT 2 using a conventional contact type probe.

In FIG. 1, the device under test 2 is attached to the base 1. Further, the contact type mouthpiece 15 having a sphere 15a at its tip is attached to moving members 51, 52 and 53 provided so as to be movable in three dimensions of X, Y and Z. Then, the surface 2a of the DUT 2 is traced by the sphere 15a of the contact probe 15.

As another conventional example, Japanese Patent Laid-Open No. 10-1
As disclosed in Japanese Patent Publication No. 9504, there is a precision three-dimensional shape measuring device that uses three mirror surfaces as a measurement reference of coordinate position.

As another conventional example, JP-A-5-57
As disclosed in Japanese Laid-Open Patent Publication No. 606, there is a shape measuring device configured integrally with a polishing device. With this device,
It is an apparatus that can correct the shape of an object to be measured with a desired accuracy by performing shape correction and then performing a correction polishing process according to the measurement result.

[0007]

However, in the above-mentioned conventional example, there are the following problems caused by the measurement environment, and precise measurement cannot be performed.

(1) The temperature of the object to be measured easily changes.

The temperature of the object to be measured depends on its ambient temperature. In the conventional example, it is necessary to control the room temperature with high accuracy in order to keep the air temperature in the room where the three-dimensional shape measuring apparatus is installed constant. This should reduce temperature changes, especially during shape measurement. However, since the specific heat of air is small, it is difficult to control the temperature of liquid. When the temperature of the object to be measured is different from the measurement environment, it is necessary to attach the object to be measured to the measuring device and then leave it for a long time in order to adjust the temperature. Due to such a cause, when the temperature of the measured object changes, the measured object deforms according to the coefficient of thermal expansion of the material, which causes a measurement error.

(2) It is affected by dust on the surface of the object to be measured.

If there is dust on the surface of the object to be measured, the probe traces the surface of the object, resulting in a measurement error. In the conventional example, since it is measured in the air, dust floating in the air accumulates on the surface of the object to be measured with time,
It causes a measurement error. Further, it is conceivable to install the shape measuring device in a clean room in order to eliminate dust contained in the air, but it is very difficult to reduce dust of 1 μm or less to zero.

(3) The object to be measured is deformed by gravity.

The object to be measured is generally supported at three points so as to maintain the same shape even if it is detached, but in this case, the number of supporting points is small, so that the object to be measured is caused by its own weight. Has a large amount of deformation. In addition, gravity varies from region to region, so due to the difference in the location where the shape measuring device is installed,
The amount of self-weight deformation is different. Furthermore, since the tidal force due to the moon or the like also changes the gravitational acceleration, the amount of self-weight deformation changes depending on the position of the moon. Such self-weight deformation differs from the original shape of the object to be measured and causes a measurement error.

(4) It is necessary to clean the polishing liquid after polishing.

A process of performing shape measurement and correction polishing and repeating the measurement and processing cycles until the target accuracy is reached is an effective means for producing a precise optical element. However, it is necessary to immerse the object to be measured in the polishing liquid during the polishing process. Then, fine particles called polishing abrasive grains are turbid in the polishing liquid, and if the object to be measured is left in the air with the polishing liquid attached, the particles will agglomerate on the surface of the object to be measured and be removed. Doing so will scratch the object to be measured. Therefore, when the polishing process is completed, it is necessary to clean the surface of the object to be measured before the surface is dried.

The first object of the present invention is to make the temperature of the object to be measured constant.

A second object of the present invention is to remove dust on the surface of the object to be measured.

A third object of the present invention is to reduce the influence of work deformation due to gravity.

A fourth object of the present invention is to omit the step of cleaning the polishing liquid after polishing.

A fifth object of the present invention is to simply construct the above measuring device.

[0021]

Means for Solving the Problems (1) In claim 1 of the present invention, an object to be measured is placed in a water tank. The liquid that fills the water tank has a larger specific heat than air, so the temperature is unlikely to change. Therefore, the temperature change of the measured object can be suppressed. As a result, the deformation of the object to be measured due to the temperature can be suppressed, and highly accurate shape measurement can be performed.

Since liquid is heavier than air, stronger buoyancy acts on dust. As a result, even if there is dust, it is possible to reduce the possibility that it will accumulate on the surface of the object to be measured. Therefore, it is possible to reduce the risk of measuring the dust of the object to be measured as a shape, and it is possible to measure the shape with high accuracy.

Since the liquid generates a buoyancy force against the object to be measured against gravity, the deformation due to its own weight can be suppressed. Therefore, the original shape of the object to be measured can be measured, and highly accurate shape measurement can be performed.

(2) In the second aspect of the present invention, the ultrasonic wave generator is provided in the water tank. Before measuring the shape, or while measuring the shape, activate the ultrasonic generator,
By peeling off the dust adhering to the object to be measured by the vibration, the influence of the dust can be reduced. as a result,
Highly accurate shape measurement is possible.

(3) In claim 3 of the present invention, the temperature of the liquid is controlled to a constant temperature by the temperature control device. By keeping the temperature of the liquid in direct contact with the measured object constant, it is possible to suppress the temperature change of the measured object. Therefore, deformation due to temperature can be reduced, and highly accurate shape measurement can be performed.

(4) In claim 4 of the present invention, the specific gravity of the liquid is made substantially the same as that of the object to be measured. If the specific gravity is the same, the weight and buoyancy of the object to be measured are balanced. Moreover, since the magnitude of the gravitational acceleration does not change and the entangled state does not change, the deformation due to its own weight can be reduced. Since the deformation of the object to be measured due to its own weight can be reduced, highly accurate shape measurement can be performed.

(5) In the fifth aspect of the present invention, the water level of the liquid is kept constant. The liquid may gradually evaporate, but when the liquid evaporates, the pressure exerted by the liquid on the object to be measured also decreases. This means that the force applied to the object to be measured changes and the shape of the object to be measured changes. The shape of the object to be measured that changes during shape measurement causes a shape error. It is also possible that the object to be measured is partially exposed to the air when the water level drops extremely. According to the present invention, even if it evaporates, the water level is kept constant, so there is no such concern, and highly accurate shape measurement can be performed.

(6) In claim 6 of the present invention, the container filled with the liquid is made of a heat insulating material. The liquid is considered to evaporate, but the evaporation always lowers the temperature below the ambient temperature. Further, even when the temperature of the liquid is controlled, the temperature does not always exactly match the environmental temperature. When the temperature of the liquid is different from the temperature of the shape measuring device, especially the temperature of the base, heat flows in and out of the two, and the temperature of the shape measuring device partially changes. Such a temperature change causes thermal deformation of the main parts of the shape measuring device, and reduces the shape measuring accuracy.
Therefore, a heat insulating material is provided between the liquid and the shape measuring device to prevent heat from flowing in and out between the two. Then, the partial temperature change of the shape measuring device can be suppressed, and the shape measuring accuracy can be improved.

(7) In claim 7 of the present invention, the liquid is a polishing liquid. When the shape is measured after the correction polishing process, the step of removing the polishing liquid can be omitted, so that the scratch problem that occurs during cleaning of the polishing liquid can be avoided. Further, by omitting the steps, time can be saved, so that the cost can be reduced.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) FIGS. 1 and 2 show a first embodiment. In the figure, reference numeral 1 is a base of a shape measuring apparatus main body (not shown), and an object to be measured is usually attached to this base. Reference numeral 2 is an object to be measured, which is attached to the base 1 via the spacer 3. This mounting method is
Remove 3 points to improve reproducibility. For example, it is performed as disclosed in Japanese Patent Laid-Open No. 8-66841. The rake 4 is fixedly provided on the base 1, the heat insulating material 5 is provided on the bottom portion of the rake 4, and the rake 4 is filled with the liquid 6. The liquid 6 and the base 1 are separated by the heat insulating material 5, and have a structure in which they do not come into direct contact with each other. It is preferable that the liquid does not react with the object to be measured, the probe, etc., and has a slow volatilization rate. For example, non-volatile oils, hydrocarbons,
Fluorocarbons, alcohols, or water are possible. A liquid having the same specific gravity as that of the object to be measured is preferable. The specific gravity of the liquid can be adjusted to some extent by appropriately selecting the molecular weight.

A drain 7 is provided on the rake 4 and is used for discharging the liquid when the shape measurement is completed. An ultrasonic transducer 8 is provided inside the bucket 4, and a drive amplifier 9
Generate ultrasonic waves. There is a thermometer 1 inside the cage 4.
0 and a heat exchanger 11 are provided and connected to the temperature controllers 12, respectively, and the temperature of the liquid is adjusted so that the indicated value of the thermometer becomes constant. At this time, the temperature control target is made to coincide with the environmental condition that guarantees the shape of the measured object. For example, in the case of an object to be measured for which it is necessary to guarantee the shape at 23 degrees, the liquid temperature is set to 23 degrees. However, in the case of an object to be measured that has no temperature conditions, the average room temperature is used. In this case, the liquid often has a value lower than room temperature due to the heat of vaporization.
It is sufficient for the temperature control system consisting of 0, 11, and 12 to perform only heating. That is, a temperature control system with a refrigerator is not necessary.
Furthermore, an agitator 13 for agitating the liquid is provided in the bowl 4 and connected to the power source 14. In this state, the surface of the object to be measured is traced by using the probe 15 connected to the shape measuring device (not shown).

With the above configuration, the shape of the object to be measured is measured according to the flowchart shown in FIG. First, the object to be measured is attached to the base 1 via the spacer 3 (2
01). Next, pour liquid 6 until the object to be measured is completely immersed 4
(202). Next, the stirrer 13 is activated to allow the liquid to slowly flow inside the bowl 4 (20
3). This makes the temperature of the liquid in the rake uniform. Next, the temperature control device consisting of 10, 11 and 12 is operated to control the temperature of the liquid to a predetermined value (2
04). Wait until the liquid temperature is constant (205).
The ultrasonic transducer 8 is operated to ultrasonically clean the object to be measured (206). As a result, the dust attached to the object to be measured is released and floats in the liquid. The ultrasonic waves are generated for a certain period of time and then stopped. This is because the measurement error becomes large when vibrating during shape measurement. Further, the dust floating in the liquid has a strong buoyancy as compared with the case of floating in the air, and thus is unlikely to be deposited on the surface of the object to be measured.

Next, the shape is measured (207). The shape is measured by tracing the surface of the object to be measured 2 with the probe 7 and measuring the position of the probe at that time. The vibration of the stirring motor is large, which may affect the shape measurement error. In that case, the stirring device is stopped immediately before the shape measurement. When the shape measurement is completed, the temperature control device is stopped (208) and the stirring device is stopped (2
09). The liquid is extracted from the drain 7 (210) and the DUT 2 is removed (211).

If the object to be measured is removed without extracting the liquid 6, the step of filling the liquid (202) and the step of extracting the liquid (210) can be omitted. Furthermore, since it is not necessary to stop the temperature control device, the temperature control device can be always operated. Therefore, the step (204) of operating the temperature control device and the step (208) of stopping the temperature control device can be omitted. In the step (205) of waiting until the temperature becomes constant, the temperature of the liquid has already become constant, so it is shortened by waiting for the time until the temperature of the measured object becomes constant. It

It is important that the ultrasonic transducer 8 is in contact with the liquid 6. For example, whether the ultrasonic transducer is fixed to the spacer 3, fixed to the DUT 2, floated in the liquid 6, or fixed to the probe 7, the ultrasonic transducer is It must always be in contact with the liquid 6 when it is activated.

It is also conceivable that the ultrasonic transducer may be operated even during the shape measurement, at the expense of the shape measurement accuracy. This is because when the probe is a contact probe (mechanical probe), the probe does not follow the rapid vibration called ultrasonic waves. That is, the shape measurement error due to ultrasonic vibration is small.

This embodiment has the following effects.

1) Since the object to be measured is placed in a temperature-controlled liquid to measure the shape, the temperature of the object to be measured is kept constant, and the accuracy of shape measurement is improved.

2) Since the shape is measured immediately after ultrasonic cleaning, a clean surface to be measured can be obtained after cleaning. Therefore, it is possible to reduce the influence of dust adhering to the surface and improve the accuracy of shape measurement. Further, since the dust floating in the liquid due to the washing receives the buoyancy force from the liquid, the amount of the dust accumulated on the surface of the object to be measured can be reduced.

3) By making the specific gravity of the liquid equal to the specific gravity of the object to be measured, it becomes possible to balance gravity and buoyancy. At this time, it is possible to reduce the influence of the self-weight deflection, and the shape measurement accuracy is improved.

Even if the gravitational acceleration changes due to the location of the shape measuring device or the tidal force of the moon,
Since the self-weight deflection is already reduced, its influence can be eliminated. As a result, the accuracy of shape measurement is improved.

4) Since there is the heat insulating material 5 between the temperature-controlled liquid 6 and the base 1, the temperature change of the base 1 can be suppressed even if the temperatures of both are not exactly the same. Since the base 1 is a part of the shape measuring device and is one of the accuracy standards for mounting the object to be measured, deformation due to temperature change can be suppressed, and shape measuring accuracy is improved.

5) Regarding the constant temperature of the object to be measured, the air temperature having a small specific heat has been conventionally controlled, while the liquid temperature having a large specific heat is controlled, so that the control is simple. It is possible to configure with a relatively small temperature control device. Therefore, the device cost can be reduced.

6) Regarding reducing dust on the surface of the object to be measured, it is not necessary to prepare an expensive clean room for the purpose of reducing accumulated dust, unlike the conventional case.
The device cost can be reduced.

(Second Embodiment) FIGS. 3 and 4 show a second embodiment. In the figure, reference numeral 1 is a base of a shape measuring apparatus main body (not shown), and an object to be measured is usually attached to this base. Reference numeral 2 is an object to be measured, which is attached to the base 1 via the spacer 3. This attachment method is performed at three points in order to improve reproducibility of attachment and detachment. The rake 4 is fixedly provided on the base 1, the heat insulating material 5 is provided on the bottom portion of the rake 4, and the rake 4 is filled with the liquid 6. The liquid 6 and the base 1 are separated by the heat insulating material 5, and have a structure in which they do not come into direct contact with each other. Ultrasonic transducer 8 inside the bucket 4
Is provided, and the drive amplifier 9 generates ultrasonic waves. An agitator 13 for agitating the liquid is provided in the bowl 4 and connected to a power source 14. Further, a water level gauge 16 for measuring the water level of the liquid 6 is provided in the cage 4.

Further, the second rake 17 is provided in parallel with the shape measuring device, and the same liquid 6 as described above is filled in the second rake, and the thermometer 10 and the heat exchanger 1 are provided inside the second rake 17.
1 is provided and is connected to each of the temperature controllers 12, and the temperature of the liquid is adjusted so that the indicated value of the thermometer becomes constant. At this time, the temperature control target is made to coincide with the environmental condition that guarantees the shape of the measured object. For example, in the case of an object to be measured for which it is necessary to guarantee the shape at 23 degrees, the liquid temperature is set to 23 degrees. However, in the case of an object to be measured that has no temperature conditions, the average room temperature is used. In this case, the liquid often has a value lower than room temperature due to the heat of vaporization, so that the temperature control system consisting of 10, 11 and 12 only needs to perform heating. That is, a temperature control system with a refrigerator is not necessary. In addition, a second water level gauge 18 is provided in the second bowl.

A pipe 19 and a pump 20 are installed in the first bowl 4 so that the liquid flows from the first bowl 4 to the second bowl 17. A pipe 21, a pump 22, and a filter 23 are installed in the second bucket 17, and the liquid is allowed to flow from the second bucket 17 to the first bucket 4.

A water level control device 24 is provided, and the first water level meter 1
The signal from 6 and the signal from the second water gauge 18 are connected, and the pumps 20 and 22 are connected.

With the above configuration, the shape of the object to be measured is measured according to the flowchart shown in FIG. First, as a preparatory step, the temperature control device including the second bowls 10, 11 and 12 is operated to control the temperature of the second bowl liquid to a predetermined temperature (301). Next, the object to be measured is attached to the base 1 via the spacer 3 (30
2). Next, the liquid 6 is poured into the bowl 4 until the object to be measured is completely immersed (303). At this time, the water level control device 24 operates the pump 22 until the first water level gauge 16 outputs a predetermined value. The predetermined value is a water level at which the liquid completely sinks the measured object. The pump 22 sucks the liquid 6 from the second bark 17 and pumps it to the filter 23. Dust contained in the liquid is removed by the filter 23, and the dust-free liquid exiting the filter is guided to the first bowl by the pipe 21.

When the first water level gauge 16 reaches a predetermined value, the water level control device operates the pump 20. The pump 20 sucks the liquid 6 from the first pail 4 through the pipe 19 and the second
Pour water into the bowl. The liquid circulates between the first and second pail. The stirrer 13 is then activated to allow the liquid to slowly flow inside the jar 4 (304). This makes the temperature of the liquid in the rake uniform. In this state, wait for a while until the temperature of the object to be measured stabilizes (305). The ultrasonic transducer 8 is activated to ultrasonically clean the object to be measured (306). As a result, the dust attached to the object to be measured is released and floats in the liquid. The ultrasonic waves are generated for a certain period of time and then stopped. This is because the measurement error becomes large when vibrating during shape measurement. Further, the dust floating in the liquid has a strong buoyancy as compared with the case of floating in the air, and therefore is unlikely to accumulate on the surface of the object to be measured. Further, the suspended dust is removed by the filter 23 while the liquid circulates between the first and second buckets, so that the influence of the dust is reduced.

Next, the shape is measured (307). The shape is measured by tracing the surface of the object to be measured 2 with the probe 7 and measuring the position of the probe at that time. The vibration of the stirring motor is large, which may affect the shape measurement error. In that case, the stirring device is stopped immediately before the shape measurement. When the shape measurement is completed, the stirring device is stopped (308). Then drain from the rake 4 (3
09). At this time, the water level control device 24 stops the pump 22 and stops water injection, and then operates the pump 20 until the first water level gauge 16 outputs a predetermined value to drain the water. Here, the predetermined value is a water level at which the liquid is below the object to be measured. By this action, the liquid in the rake 4 will fall
Move to. In addition, the water level control device 24 has a second
The water level of is also measured by the second water level gauge 18, and the operation is stopped in advance when this rake overflows. Next, the DUT 2 is removed (310).

If the object to be measured is removed without extracting the liquid 6, the step of pouring the liquid (303) and the step of draining the liquid (309) can be omitted. In this case, the liquid will always remain inside the bowl 4, so the thermometer 10
The installation position of can be set inside the cage 4. With this configuration, the thermometer can be brought closer to the object to be measured, so that the temperature control accuracy of the object to be measured can be improved.

It is important that the ultrasonic transducer 8 is in contact with the liquid 6. For example, whether the ultrasonic transducer is fixed to the spacer 3, fixed to the DUT 2, floated in the liquid 6, or fixed to the probe 7, the ultrasonic transducer is It must always be in contact with the liquid 6 when it is activated.

In addition to the case of the first embodiment, this embodiment has the following effects.

1) Since the temperature of the liquid can be adjusted in advance, it is not necessary to wait until the temperature of the liquid becomes constant as in the first embodiment. However, the waiting time until the temperature of the object to be measured becomes constant is the same as in the first embodiment.

2) Since it is not necessary to put the temperature control device in the case 4, the size of the case can be reduced. If this bonnet can be made smaller, the shape measuring device to which it is attached can also be made smaller.

3) Since water injection and drainage are performed by a pump, there is no human manual work and automation is possible. If it can be automated, the burden on the operator can be reduced and the operating cost of the device can be reduced. Further, it is possible to prevent water leakage accidents caused by water injection and drainage due to human error.

(Third Embodiment) FIGS. 5 and 6 show a third embodiment. A liquid circulation system is added to the first embodiment, and temperature control is performed in the middle of the circulation path. Furthermore, the circulation system allows the flow of liquid to be inside the skein, so that the stirring device can be omitted.

FIG. 5 shows a third embodiment. In the figure, reference numeral 1 is a base of a shape measuring apparatus main body (not shown), and an object to be measured is usually attached to this base. Reference numeral 2 is an object to be measured, which is attached to the base 1 via the spacer 3. This attachment method is performed at three points in order to improve reproducibility of attachment and detachment. The rake 4 is fixedly provided on the base 1, the heat insulating material 5 is provided on the bottom portion of the rake 4, and the rake 4 is filled with the liquid 6. The liquid 6 and the base 1 are separated by the heat insulating material 5, and have a structure in which they do not come into direct contact with each other.
A drain 7 is provided on the rake 4 and is used for discharging the liquid when the shape measurement is completed. An ultrasonic oscillator 8 is provided inside the bucket 4, and an ultrasonic wave is generated by the drive amplifier 9. Further, a thermometer 10 is installed inside the cage 4.

A pipe 19 is connected to the cage 4, a heat exchanger 11 and a pump 22 which can be operated in-line are connected, and the liquid is pressure-fed to the filter 23. The liquid that has exited the filter 23 passes through the pipe 21 and returns to the reservoir 4 again. Temperature clock 10,
The heat exchanger 11 is connected to the temperature control device 12 and adjusts the temperature of the liquid so that the indicated value of the thermometer becomes constant. At this time, the temperature control target is made to coincide with the environmental condition that guarantees the shape of the measured object. For example, in the case of an object to be measured for which it is necessary to guarantee the shape at 23 degrees, the temperature of the liquid is set to 23 degrees. However, in the case of an object to be measured that has no temperature conditions, the average room temperature is used. In this case, the liquid often has a value lower than room temperature due to the heat of vaporization, so that the temperature control system consisting of 10, 11 and 12 only needs to perform heating. That is, a temperature control system with a refrigerator is not necessary. In this state, the probe 15 connected to the shape measuring device (not shown)
To trace the surface of the object to be measured.

With the above configuration, the shape of the object to be measured is measured according to the flowchart shown in FIG. First, the object to be measured is attached to the base 1 via the spacer 3 (4
01). Next, pour liquid 6 until the object to be measured is completely immersed 4
(402). Next, the pump 22 is activated to circulate the liquid inside the rake 4 through the heat exchanger 11 and the filter 23 and return to the rake 4 again (403).
Inside the bucket 4, a flow of liquid occurs and the temperature becomes uniform. Next, the temperature control device consisting of 10, 11 and 12 is operated to control the temperature of the liquid to a predetermined value (4
04). Wait until the liquid temperature becomes constant (405).

The ultrasonic vibrator 8 is operated to ultrasonically clean the object to be measured (406). As a result, the dust attached to the object to be measured is released and floats in the liquid. The ultrasonic waves are generated for a certain period of time and then stopped. Further, the dust floating in the liquid has a strong buoyancy as compared with the case of floating in the air, and thus is unlikely to be deposited on the surface of the object to be measured. Further, dust is gradually removed by the filter 23 in the middle of the circulation path.

Next, the shape is measured (407). The shape is measured by tracing the surface of the object to be measured 2 with the probe 7 and measuring the position of the probe at that time. When the shape measurement is completed, the temperature control device is stopped (408) and the circulation system is stopped (409). The liquid is extracted from the drain 7 (410), and the DUT 2 is removed (411).

If the object to be measured is removed without extracting the liquid 6, the step of filling the liquid (402) and the step of extracting the liquid (410) can be omitted. Furthermore, since it is not necessary to stop the temperature control device, the step (404) of operating the temperature control device and the step (408) of stopping the temperature control device can be omitted. In the step (405) of waiting for the temperature to become constant, the temperature of the liquid has already become constant, so the time until the temperature of the object to be measured becomes constant can be shortened. To be done.

In addition to the case of the first embodiment, this embodiment has the following effects.

1) In order to make the temperature in the bowl 4 uniform, a stirring device was provided in the first embodiment, but in the third embodiment the water flow by the circulation system is used, so it is quieter. The temperature can be made uniform. This makes it possible to reduce vibration during shape measurement and improve shape measurement accuracy.

2) Since the circulation system having the filter is provided, it is possible to continuously remove dust floating in the liquid. As a result, it is possible to reduce the possibility that the shape measurement result will be deteriorated by dust.

3) In contrast to the second embodiment, since the liquid is circulated in one bowl, the water level control device and the water level gauge can be eliminated, and the device cost can be reduced.

(Fourth Embodiment) FIG. 7 shows a fourth embodiment. In contrast to the third embodiment, the water injection mouth is fixed to the probe and the thermometer is installed in the circulation path.

In the figure, reference numeral 1 is a base of a shape measuring apparatus main body (not shown), and the object to be measured is usually attached to this base. Reference numeral 2 is an object to be measured, which is attached to the base 1 via the spacer 3. This attachment method is performed at three points in order to improve reproducibility of attachment and detachment. The rake 4 is fixedly provided on the base 1, the heat insulating material 5 is provided on the bottom portion of the rake 4, and the rake 4 is filled with the liquid 6. The liquid 6 and the base 1 are separated by the heat insulating material 5, and have a structure in which they do not come into direct contact with each other. The drain 4 is provided in the bucket 4,
It is used to drain the liquid when the shape measurement is completed.
An ultrasonic oscillator 8 is provided inside the bucket 4, and an ultrasonic wave is generated by the drive amplifier 9.

A pipe 19 is connected to the cage 4, a heat exchanger 11 and a pump 22 which can be operated in-line are connected, and the liquid is pressure-fed to the filter 23. The liquid discharged from the filter 23 is guided to the thermometer 10, measures the temperature, passes through the pipe 21, and is poured into the inside of the skein 4 from the nozzle 25 fixed to the probe. Here, the pipe connected to the probe is made of a flexible tube, for example. This is because the probe moves vertically and horizontally. Temperature clock 10, heat exchanger 11
Is connected to the temperature control device 12 and adjusts the temperature of the liquid so that the indicated value of the thermometer becomes constant. In this state,
The surface of the object to be measured is traced using the probe 15 connected to a shape measuring device (not shown).

The operation is the same as in the case of the third embodiment and will not be repeated.

In addition to the case of the third embodiment, this embodiment has the following effects.

1) Since the clean liquid from which dust has been removed is supplied to the vicinity of the probe where the measurement is performed, the influence of dust can be reduced more effectively.

2) Since the liquid is always supplied to the probe portion even if the water level of the liquid is lowered, the probe does not run on the surface of the dry object to be measured. In the case of the contact type probe, there is a possibility of causing scratches when the dry surface to be measured is scanned, so that the danger can be avoided.

(Fifth Embodiment) FIG. 8 shows a fifth embodiment. The first embodiment is an embodiment in which these are arranged on the detachable plate 26, while the case and the heat insulating material are fixed directly to the base of the shape measuring apparatus. With this configuration, since it is not necessary to set the object to be measured on the shape measuring apparatus, in addition to the case of the first embodiment,
Further, it has the following effects.

1) Since the object to be measured can be set outside the shape measuring apparatus, the time for occupying the shape measuring apparatus can be shortened. That is, the operating rate of the shape measuring device can be improved.

2) Batch processing can be performed by preparing a plurality of removable plates 26, and a bail fixed to them. That is, in advance,
Efficiently measure the shape of the object to be measured by setting a plurality of objects to be measured on each plate 26, adjusting the temperature, and mounting this on a shape measuring device in order of stable temperature and measuring the shape. can do.

(Sixth Embodiment) The sixth embodiment is a case where the liquid is a polishing liquid as compared with the above-described embodiments. Although small particles called polishing abrasive particles are turbid in the polishing liquid, their influence can be ignored if shape measurement accuracy is not so required.

The following procedure is required in the processing step in which the shape measurement of the object to be measured and the correction polishing are repeated.

1) Set the object to be measured in the shape measuring apparatus 2) Measure the shape 3) Remove the object to be measured from the shape measuring apparatus 4) Set the object to be measured in the polishing apparatus 5) Correct polishing 6 ) The modified polishing cycle of removing the object to be measured from the polishing apparatus is continued until the target accuracy is reached. On the other hand, as shown in the fifth embodiment, if the removable method is used and the liquid is the polishing liquid, the following advantages can be obtained.

1) The steps of setting and removing the object to be measured can be omitted. However, it is necessary to attach and detach the plate 26.

2) It is not necessary to clean the object to be measured with the polishing liquid.

Further, as shown in FIG. 8, a polishing machine and a shape modifying machine as disclosed in 1995 Proceedings of Academic Conference of Abrasive Grain Processing Society, page 115, or Japanese Patent Laid-Open No. 5-57606. In the case of a system in which the device is integrated, there is no need for a plate to be attached and detached as in the fifth embodiment, and it is possible to directly fix the case and the heat insulating material to the device as in the first embodiment.

[0085]

As described above, according to the present invention,
According to the first aspect, when the object to be measured is placed in the water tank and the shape is measured, the temperature of the object to be measured is less likely to change as compared with the case of measuring in air. Therefore, the deformation of the object to be measured due to the temperature can be suppressed, and highly accurate shape measurement can be performed.

Since the liquid is heavier than the air, it is possible to reduce the possibility that dust is accumulated. Therefore, it is possible to reduce the risk of measuring the dust of the object to be measured as a shape, and it is possible to measure the shape with high accuracy. The liquid generates buoyancy against the object to be measured, so that the self-weight deformation can be suppressed. Therefore, the original shape of the object to be measured can be measured, and highly accurate shape measurement can be performed.

A material which reacts with moisture in the air and undergoes a chemical change relatively slowly, that is, a material having a stiffening property, for example, a non-linear optical material such as potassium dihydrogen phosphate used for light wavelength conversion, is dipped in silicon oil or the like. Since the shape is measured in the state, it can be measured without touching the air.

According to the second aspect of the present invention, the influence of dust can be reduced by activating the ultrasonic generator before measuring the shape and peeling the dust adhering to the object to be measured by the vibration. Therefore, highly accurate shape measurement is possible.

According to the third aspect, the temperature change of the measured object can be suppressed by controlling the temperature of the liquid which is in direct contact with the measured object by the temperature control device. Therefore, deformation due to temperature can be reduced, and highly accurate shape measurement can be performed.

According to the fourth aspect, by making the specific gravity of the liquid substantially the same as that of the object to be measured so that the weight applied to the object to be measured and the buoyancy force are balanced, the deformation due to its own weight can be reduced. Since the deformation of the object to be measured due to its own weight can be reduced, highly accurate shape measurement can be performed.

According to the fifth aspect, since the water level of the liquid can be kept constant, the water surface of the liquid changes due to the evaporation of the liquid and the like, the pressure applied to the measured object changes, and a part of the measured object changes. It is possible to reduce the risk of the liquid coming out of the liquid surface.

According to the sixth aspect, by configuring the container filled with the liquid with a heat insulating material, the temperature change of the shape measuring apparatus can be suppressed, and as a result, the shape measuring accuracy can be improved.

According to the seventh aspect, by using a polishing liquid as the liquid, the step of removing the polishing liquid can be omitted. When the correction polishing process and the shape measurement are repeated, it is possible to avoid the scratching problem that occurs when cleaning the polishing liquid. Further, by omitting the step of removing the polishing liquid, time can be saved, so that the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a flow chart of a first embodiment of the present invention.

FIG. 3 is a diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram showing a flowchart of a second embodiment of the present invention.

FIG. 5 is a diagram showing a third embodiment of the present invention.

FIG. 6 is a diagram showing a flowchart of a third embodiment of the present invention.

FIG. 7 is a diagram showing a fourth embodiment of the present invention.

FIG. 8 is a diagram showing a fifth embodiment of the present invention.

FIG. 9 is a diagram showing a sixth embodiment of the present invention.

FIG. 10 is a diagram illustrating a conventional shape measuring device.

[Explanation of symbols]

1 base 2 DUT 3 spacers 4 Oke 5 insulation 6 liquid 7 drain 8 Ultrasonic transducer 9 Ultrasonic transducer drive amplifier 10 thermometer 11 heat exchanger 12 Temperature control device 13 Stirrer 14 Power supply for stirring device 15 probes 16 Water gauge 17 Second Oke 18 Second water gauge 19 plumbing 20 pumps 21 piping 22 pumps 23 Filter 24 Water level control device 25 nozzles 26 plates 51 Y slide 52 X slide 53 Z slide

Claims (7)

[Claims] 1. A base having a base, an object to be measured set on the base, a probe, and a trace mechanism for tracing the probe on the surface of the object to be measured, and position information from a probe position measuring means is processed. In a so-called three-dimensional measuring device for measuring the shape of an object to be measured, the apparatus has a water tank, the object to be measured is installed in the water tank, and the water tank is measured while being filled with a liquid. apparatus. 2. The three-dimensional shape measuring apparatus according to claim 1, further comprising an ultrasonic wave generator inside the water tank. 3. The three-dimensional shape measuring apparatus according to claim 1, further comprising a liquid temperature control device. 4. The three-dimensional shape measuring apparatus according to claim 1, wherein the specific gravity of the liquid is substantially equal to the specific gravity of the object to be measured. 5. The water level gauge as set forth in claim 1, wherein a second water tank is provided, and a pipe between the two water tanks is connected through a pump for taking in and out the liquid, and the indicated value of the water level gauge as described above. A three-dimensional shape measuring apparatus characterized in that a control device for controlling the rotation of the pump is provided so as to keep constant. 6. The three-dimensional shape measuring apparatus according to claim 1, wherein the container for containing the liquid is made of a heat insulating material. 7. The three-dimensional shape measuring apparatus according to claim 1, wherein the liquid is a polishing liquid used for polishing.