JP2010007812A - Vibration damping device and measuring device with this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration damping device capable of suppressing transmission of vibration from outside to a measuring device without generating vibration by itself for which burden of adjustment and maintenance are small and the measuring device equipped with this. <P>SOLUTION: A first metal plate 2 installed on an installation surface T, a second metal plate 4 arranged on the first metal plate 2, a vibration damping rubber 3, gripped between the first metal plate 2 and a second metal plate 4, which can be elastically deformed by receiving vibration from the first metal plate 2 and a vibration damping table 5 arranged on the second metal plate 4 capable of absorbing the vibration by being at least partially elastically deformed corresponding to the vibration from the second metal plate 4 wherein at least part of the measuring device 6 is loaded on its upper surface. A band of frequency of vibration absorbed by the first metal plate 2, the vibration damping rubber 3 and the second metal plate 4 is different from a band of frequency of vibration absorbed by the vibration damping table. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vibration isolator for making it difficult to transmit external vibration to a measuring instrument that requires high resolution, and a measuring apparatus having the same.

  For example, a photothermal conversion measuring apparatus according to Patent Document 1 is known as a measuring instrument that requires high resolution. In this type of measuring instrument, there is a problem that the measuring performance of the measuring instrument deteriorates as the background measurement signal (background noise) increases due to noise sources such as vibration and sound generated in the experimental environment to be measured. .

As a countermeasure for reducing such noise sources, for example, it is conceivable to use an active vibration isolator as disclosed in Patent Document 2. The active vibration isolator disclosed in Patent Document 2 detects vibration transmitted to a surface plate by a vibration sensor, calculates a driving amount for removing the vibration based on the detection result, and an actuator according to the driving amount. (Bottom board) is driven.
JP 2004-301520 A JP 2000-120765 A

  However, since the active vibration isolator according to Patent Document 2 requires a precise electric system for feeding back the detected vibration as the drive amount of the actuator, the adjustment and maintenance are heavy, and the vibration isolator itself is There was a problem of becoming expensive.

  Further, the active vibration isolator according to Patent Document 2 has a configuration in which the actuator is actively driven to cancel the vibration. Therefore, such an active vibration isolator is actively used for a measuring instrument that requires high resolution as described above. This may cause a decrease in measurement accuracy.

  The present invention has been made in view of the above problems, and is a vibration isolation device that can reduce the burden of adjustment and maintenance, and can prevent external vibrations from being transmitted to a measuring instrument without causing vibrations by itself. And it aims at providing a measuring device provided with this.

  In order to solve the above problems, the present invention is a vibration isolator provided between an installation surface and a measuring instrument for suppressing vibrations from the installation surface from being transmitted to the measuring instrument, A first metal plate installed on an installation surface, a second metal plate provided on the first metal plate, and sandwiched between the first metal plate and the second metal plate; An elastic member that can be elastically deformed in response to vibration from the metal plate and provided on the second metal plate, and at least a part of the measuring device is placed on the upper surface of the elastic member, and from the second metal plate A vibration isolation table capable of absorbing the vibration by elastically deforming at least a part in response to the vibration, and a frequency of vibration absorbed by the first metal plate, the elastic member, and the second metal plate And the frequency band of vibration absorbed by the vibration isolation table are different. Providing anti-vibration apparatus is characterized.

  According to the vibration isolator of the present invention, the elastic member provided between the first metal plate and the second metal plate and the elastic deformation of at least a part of the vibration isolation table absorb vibration from the installation surface. Therefore, unlike the active vibration isolation table, no electrical adjustment is required, and the burden of maintenance can be reduced.

  Further, in the present invention, since the vibration isolator itself can absorb vibrations from the installation surface without actively vibrating, when the measuring instrument requiring high resolution is placed, A situation in which the measurement accuracy is lowered can be avoided.

  Furthermore, in the present invention, the frequency band of vibration absorbed by the first metal plate, the second metal plate and the elastic member is different from the frequency band of vibration absorbed by the vibration isolation table. Even if an active vibration isolation table is not used, vibrations in a wide frequency band can be absorbed, and the vibration isolation performance can be improved.

  In the vibration isolation device, the vibration isolation table includes a main body portion attached to the second metal plate, a mounting portion on which at least a part of the measuring device is mounted, and the main body portion and the mounting portion. It is preferable that the vibration chamber be absorbed by a change in volume of the air chamber.

  According to this configuration, vibration can be absorbed between the main body portion and the mounting portion by the air spring using the compression elasticity of the air in the air chamber.

  In the vibration isolation device, it is preferable that at least the first metal plate of the first metal plate and the second metal plate has a weight larger than that of the measuring device.

  According to this configuration, since the measuring device is installed through the first metal plate having a weight larger than that of the measuring device, the weight given to the installation surface is larger than when only the measuring device is installed. This makes it difficult for the measuring instrument to move relative to the installation surface. Therefore, it can suppress more effectively that the vibration from an installation surface is transmitted to a measuring device via a 1st metal plate.

  In addition, the present invention provides a measurement apparatus comprising the vibration isolation device and a measuring instrument that is at least partially placed on a vibration isolation table of the vibration isolation device.

  According to the measuring apparatus according to the present invention, as described above, the burden of adjustment and maintenance is small, and it is possible to suppress vibration from the installation surface from being transmitted to the measuring instrument without causing vibration on its own.

  In the measuring apparatus, the measuring device includes a mechanical chopper for generating intermittent light irradiated to the measurement object, and a measurement unit for measuring a change in the measurement object due to the intermittent light, and the mechanical It is preferable that one of the chopper and the measuring unit is arranged on the vibration isolation table and the other is arranged on the second metal plate.

  In this way, since the measurement unit for measuring the change of the measurement object and the mechanical chopper as the vibration source are arranged separately in the vibration isolation table and the second metal plate, the mechanical chopper Even if vibration occurs, this vibration is absorbed by the vibration isolation table and is difficult to be transmitted to the measurement unit. Therefore, it is possible to suppress a decrease in measurement accuracy of the measurement unit.

  In particular, it is preferable that the mechanical chopper is placed on the second metal plate, and the measurement unit is placed on the vibration isolation table.

  If it does in this way, about the measuring part which requires high resolution, suppressing transmission of vibration from a mechanical chopper to a measuring part as mentioned above, it will be from an installation surface by each metal plate, an elastic member, and a vibration isolator. Therefore, it is possible to more effectively prevent a decrease in measurement accuracy by the measurement unit.

  And the said measurement part is comprised so that the phase change of the measurement light before and behind passing through the said irradiation site | part may be measured while irradiating the measurement site | part to the irradiation site | part of the said measurement object irradiated with the said intermittent light Can do.

  In this way, it is possible to perform a quantitative analysis of a predetermined component contained in the measurement object. The principle is as follows.

  By selecting light having a wavelength for exciting the predetermined component as the intermittent light, and irradiating this intermittent light to the irradiation site of the measurement target component, a refractive index change due to the photothermal effect occurs in the measurement target component. . Since the degree of the refractive index change is proportional to the phase change of the measurement light before and after passing through the irradiation site, a quantitative analysis of a predetermined component in the measurement target component is performed by measuring the phase change. Can do.

  ADVANTAGE OF THE INVENTION According to this invention, the burden of adjustment and a maintenance is small, and it can suppress that the vibration from the outside transmits to a measuring device, without producing a vibration by itself.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic front view showing a measuring apparatus according to an embodiment of the present invention.

  With reference to FIG. 1, the measurement apparatus includes a vibration isolation device 1 provided on a predetermined installation surface T, and a measuring instrument 6 placed on the vibration isolation device 1.

  The vibration isolator 1 includes a first metal plate 2 installed on the installation surface T, a second metal plate 4 provided on the first metal plate 2, a first metal plate 2, and a second metal plate. A plurality of anti-vibration rubbers (elastic members) 3 sandwiched between 4 and a vibration isolator 5 provided on the second metal plate 4.

  Each metal plate 2 and 4 consists of an iron plate in this embodiment. As will be described later in detail, the vibration isolation performance of the vibration isolation device 1 improves as the weight of the metal plates 2 and 4 increases. It is preferable to use it. Specifically, in the present embodiment, each of the metal plates 2 and 4 has a greater weight than the measuring device 6.

  The anti-vibration rubber 3 is configured to be elastically deformed by receiving vibration from the first metal plate 2. The shape of the anti-vibration rubber 3 may be a block shape or a sheet shape.

  FIG. 2 is a front sectional view showing the configuration of the vibration isolation table 5 of FIG.

  Referring to FIG. 2, the vibration isolation table 5 includes a main body 30 attached to the second metal plate 4, a diaphragm 31 and a sealing member 32 provided on the main body 30, and the measuring device 6. And a placement portion 33 to be placed.

  The main body 30 is formed in a bottomed container shape that opens upward, a partition wall 35 provided in the middle in the vertical direction, a protrusion 36 that protrudes upward from the center of the partition wall 35, and the protrusion 36. And a through hole 37 penetrating the partition wall 35 in the vertical direction.

  The diaphragm 31 has a cylindrical portion 38 disposed in the through-hole 37 and a folded portion 39 which is an edge of the cylindrical portion and is folded outside the protruding portion 36 and is elastically deformable. Made of different materials.

  The sealing member 32 is a member that covers the outside of the protruding portion 36 from above with the diaphragm 31 interposed therebetween, and includes an insertion hole 40 that vertically penetrates at a position corresponding to the cylindrical member 38. An air chamber S <b> 1 is formed in the main body 30 by sandwiching the diaphragm 31 (the folded portion 39) between the inner surface of the sealing member 32 and the outer surface of the protruding portion 36.

  The mounting portion 33 includes a mounting table 41 on which the measuring instrument 5 is mounted, and a support bar 34 that extends downward from the mounting table 41. The support bar 34 is disposed through the insertion hole 40, and the tip thereof is fixed to the cylindrical portion 38 of the diaphragm 31.

  The vibration isolator 5 configured as described above has a structure in which the diaphragm 31 is elastically deformed by the relative displacement of the main body portion 30 and the placement portion 31, and the volume of the air chamber S1 is changed. Vibrations can be absorbed using the compression elasticity of the air in the chamber S1.

  FIG. 3 is a schematic diagram showing the overall configuration of the measuring instrument 6 of FIG.

  Referring to FIG. 3, a measuring instrument 6 includes an excitation optical system 6a for exciting an analysis target component in the sample 11, a measurement optical system 6b for performing quantitative analysis of the analysis target component, and the measurement optical system. And a signal processing device 27 for processing a signal detected by the system 6b.

  The excitation optical system 6a includes an excitation light source 7 that emits excitation light (laser (YAG double wave) light having a wavelength of 533 nm and an output of 100 mW), a mechanical chopper 8 for making the excitation light intermittent light, And a dichroic mirror 9 that reflects the excitation light.

  The measurement optical system 6b includes a laser light source 13 that emits measurement light (for example, a He—Ne laser having an output of 1 mW), a ½ wavelength plate 14 for adjusting the polarization plane of the measurement light, and a ½ wavelength plate. A polarization beam spreader (hereinafter referred to as PSB) 15 for separating the measurement light from 14 into polarizations P1 and P2, and an acousto-optic modulator (hereinafter referred to as PSB) for converting the optical frequencies of the polarizations P1 and P2. 16 and 17, mirrors 18 and 19 that reflect the polarizations P1 and P2, PSB 20 for synthesizing the polarizations P1 and P2, and polarization P2 from the PSB 20 while passing the polarization. PSB 21 that reflects the wave P1, a quarter-wave plate 22 that adjusts the polarization plane of the polarization P2 that has passed through the PSB 21, a mirror 24 that reflects the polarization P2, and a polarization of the polarization P1 reflected by the PSB 21 Adjust wavefront The quarter wave plate 23, the polarization P1 and the lens 10 for condensing the excitation light, the mirror 12 that reflects the polarization P1 that has passed through the sample 11, and the polarizations P1 and P2 from the PBS 21 A photodetector 26 for detection and a polarizing plate 25 provided between the PBS 21 and the photodetector 26 are provided.

  Hereinafter, the operation of the measuring device 6 will be described.

  Excitation light emitted from the excitation light source 7 is converted into intermittent light having a predetermined period by the mechanical chopper 8, reflected by the dichroic mirror 9, condensed by the lens 10, and irradiated on the sample 11. Thereby, the sample 11 absorbs excitation light and generates heat (photothermal effect), and the refractive index of the sample 11 changes due to the temperature rise.

  On the other hand, the measurement light emitted from the laser light source 13 has its polarization plane adjusted by the half-wave plate 14 and is split into two polarized waves P1 and P2 orthogonal to each other by the PBS 15.

  Each of the polarizations P1 and P2 is shifted in optical frequency by the AOMs 16 and 17, reflected by the mirrors 18 and 19, and synthesized by the PSB 20. Note that the frequency difference between the two polarized waves P1 and P2 is, for example, 30 MHz.

  Of the synthesized polarizations, the polarization P2 passes through the PBS 21 and is reflected by the mirror 24, and returns to the PBS 21. At this time, since the polarization P2 passes through the ¼ polarizing plate 22 twice, its polarization plane is rotated by 90 °. Therefore, the polarization P2 returning from the mirror 24 is reflected by the PBS 21 and becomes light. Guided to detector 26.

  On the other hand, of the synthesized polarized waves, the polarized light P 1 is reflected by the PBS 21, passes through the quarter-wave plate 23, the dichroic mirror 9, and the lens 10 and enters the sample 11. The excitation light is configured to be applied to the incident portion of the polarization P1 (measurement light).

  The polarized light P1 that has passed through the sample 11 is reflected by the mirror 12 and passes through the sample 11 again. The polarized wave P <b> 1 from the sample 11 passes through the lens 10, the dichroic mirror 9, and the quarter wavelength plate 23 and returns to the PBS 21. Here, since the polarization plane of the polarization P1 passes through the quarter-wave plate 23 twice, and the plane of polarization of the polarization P1 is rotated by 90 °, the polarization P1 from the sample 11 passes through the PBS 21 and is polarized. The wave P2 merges and is guided to the photodetector 26.

  Here, in the polarizing plate 25 provided between the PBS 21 and the photodetector 26, the polarized light P1 and the polarized light P2 having different optical frequencies interfere with each other as observation light and reference light, and the light of the interference light. The intensity is converted into an electric signal (hereinafter referred to as interference light intensity) by the photodetector 26.

  The signal processing device 27 analyzes the amount (concentration) of the analysis target component in the sample 11 based on the interference light intensity from the photodetector 26. Hereinafter, the principle will be described.

  The interference light intensity is represented by S2 as shown in the following equation (1).

S2 = C1 + C2 × cos (2π × f _b × t + φ) (1)
Here, C1 and C2 are constants determined by the transmittance of the optical system such as PBS and the sample 11, φ is a phase difference due to the optical path length difference between the polarizations P1 and P2, and f _b is a polarization P1 and P2. Is the frequency difference. According to the equation (1), the change in the phase difference φ can be obtained based on the change in the interference light intensity S2.

  Next, the relationship between the phase difference φ and the concentration of the analysis target component in the sample 11 will be described. The calorific value (endothermic amount) of the sample 11 when irradiated with the excitation light increases in proportion to the concentration of the analysis target component contained in the sample 11, and the sample 11 with respect to the polarization P <b> 1 corresponds to the calorific value. The refractive index changes, and the phase difference φ (the optical path length of the polarization P1 in the sample 11) changes according to the refractive index. That is, as the concentration of the analysis target component contained in the sample 11 is higher, the change in the phase difference φ due to the excitation light becomes larger. Therefore, by specifying the phase difference φ, the concentration of the analysis target component contained in the sample 11 is determined. Can be sought.

  Specifically, samples of a plurality of types of samples 11 whose concentrations of analysis target components are known are prepared in advance, the phase difference φ is measured for each sample using the measuring device 6, and the phase difference φ and The relationship with the concentration of the analysis target component is stored as a data table in a storage unit (not shown) of the signal processing device 27. When the phase difference φ of the sample 11 to be analyzed is measured, the concentration of the analysis target component can be specified by performing an interpolation process or the like based on the measurement result and the data table. It becomes.

  And in the said embodiment, since the measuring device 6 is provided on each metal plate 2, 4, the anti-vibration rubber | gum 3, and the vibration isolator 5, the vibration from the installation surface T is transmitted to the measuring device 6. It becomes possible to suppress effectively. The reason is as follows.

  In this embodiment, since each metal plate 2 and 4 is heavier than the measuring device 6, respectively, the weight given to the installation surface T becomes larger than the case where the measuring device 6 is installed directly on the installation surface T. The entire measuring apparatus is difficult to move with respect to the installation surface T. Therefore, it is possible to suppress the vibration from the installation surface from being transmitted to the measuring device 6 through the metal plates 2 and 4. Further, since the anti-vibration rubber 3 is provided between the metal plates 2 and 4, the vibration from the first metal plate 2 is absorbed by the elastic deformation of the anti-vibration rubber 3, and is measured by the measuring device 6. It becomes difficult to convey. The vibrations absorbed by the metal plates 2 and 4 and the anti-vibration rubber 3 have a relatively high frequency.

  In the present embodiment, since the vibration isolation table 5 (see FIG. 2) is provided on the second metal plate 4, air using the compression elasticity of the air in the air chamber S1 of the vibration isolation table 5 is used. The spring can absorb vibration of a relatively low frequency transmitted from the second metal plate 4. That is, in the vibration isolation device 1 according to the present embodiment, the frequency band of vibration absorbed by the metal plates 2, 4 and the vibration isolation rubber 3 is different from the frequency band of vibration absorbed by the vibration isolation table 5. Since it is set to the thing, it can suppress effectively that the vibration from the installation surface T is transmitted to the measuring device 6.

  The anti-vibration table 5 using the air spring as described above exhibits a high anti-vibration effect on the high frequency side with the resonance peak of the air spring as the apex based on the general anti-vibration theory. On the other hand, the metal plates 2 and 4 and the anti-vibration rubber 3 can be removed in an extremely low frequency range, which is difficult to achieve with the vibration isolation table 5 by utilizing the weight of the metal plates 2 and 4 in particular. Realize the vibration effect. Therefore, the combination of the vibration isolation table 5, the metal plates 2 and 4 and the vibration isolating rubber 3 achieves a high vibration isolation effect over a wide frequency range from a low frequency to a high frequency.

  As described above, according to the embodiment, the vibration isolating rubber 3 and the vibration isolation table 5 provided between the first metal plate 2 and the second metal plate 4 can be used without electrical adjustment. Since the vibration from the installation surface T can be absorbed, the maintenance burden can be reduced.

  Moreover, in the said embodiment, since the vibration isolator 1 itself can absorb the vibration from the installation surface T, without actively vibrating, when mounting the measuring device 6 in which high resolution is required. However, it is possible to avoid a situation in which the measurement accuracy is lowered due to own vibration.

  Furthermore, in the above embodiment, the frequency band of vibration absorbed by the metal plates 2, 4 and the vibration isolating rubber 3 is different from the frequency band of vibration absorbed by the vibration isolation table 5. It becomes possible to absorb vibrations in a wide frequency band, and the vibration isolation performance can be improved.

  If each metal plate 2, 4 has a larger weight than the measuring device 6 as in the above embodiment, the measurement is performed via each metal plate 2, 4 having a larger weight than the measuring device 6. Since the instrument 6 is installed, the weight given to the installation surface T is larger than when only the measurement instrument 6 is installed, and the measurement instrument 6 is difficult to move relative to the installation surface T. Therefore, it is possible to more effectively suppress the vibration from the installation surface T from being transmitted to the measuring device 6 through the metal plates 2 and 4.

  In the embodiment, both the metal plates 2 and 4 have a larger weight than the measuring device 6, but at least the first metal plate 2 of the metal plates 2 and 4 has a larger weight than the measuring device 6. If it has, the above-mentioned effect can be produced.

  Moreover, in the said embodiment, as shown in FIG. 1, although the whole measuring device 6 including both the excitation optical system 6a and the measurement optical system 6b is provided on the vibration isolator 5, it is shown in FIG. Thus, it is preferable to provide the excitation optical system 6 a on the second metal plate 4 and the measurement optical system 6 b on the vibration isolation table 5.

  In this way, it is possible to suppress the vibration generated from the mechanical chopper 8 of the excitation optical system 6a from being transmitted to the measurement optical system 6b. That is, in the embodiment shown in FIG. 4, the excitation optical system 6 a having the mechanical chopper 8 and the measurement optical system 6 b that requires high resolution are provided on separate members, and therefore the mechanical chopper 8 vibrates. Even if this occurs, this vibration is absorbed by the vibration isolation table 5 and is not easily transmitted to the measurement optical system 6b.

  In particular, as shown in the figure, if the excitation optical system 6a is provided on the second metal plate 4 and the measurement optical system 6b is provided on the vibration isolation table 5, from the mechanical chopper 8 to the measurement optical system 6b as described above. In a measurement optical system that requires high resolution while suppressing transmission of vibration, vibrations from the installation surface can be absorbed by the metal plates 2, 4, the anti-vibration rubber 3, and the vibration isolation table 5. Further, it is possible to more effectively prevent a decrease in measurement accuracy due to the measurement optical system 6b.

  Hereinafter, another embodiment capable of suppressing the vibration from the installation surface T from being transmitted to the measuring device 6 will be described with reference to FIGS.

  First, in the form shown in FIG. 5, the vibration isolation table 5 is omitted from the form shown in FIG. In this embodiment, although the function of absorbing vibrations in a relatively high frequency band is reduced, vibrations in a relatively low frequency band can be effectively absorbed by the metal plates 2 and 4 and the vibration isolating rubber 3.

  In the form shown in FIG. 6, the anti-vibration rubber 3 is omitted from the form shown in FIG. In this embodiment, the vibration absorbed by the vibration isolating rubber 3 is transmitted to the vibration isolation table 5. A relatively low frequency band of this vibration can be absorbed by the vibration isolation table 5.

  In the form shown in FIG. 7, the anti-vibration rubber 3 is omitted from the form shown in FIG. In this embodiment, vibration from the installation surface T is difficult to be transmitted at the boundary surface where the metal plates 2 and 4 overlap each other, so that transmission of vibration from the installation surface T to the measuring device 6 can be suppressed.

It is a schematic front view which shows the measuring apparatus which concerns on embodiment of this invention. It is front sectional drawing which shows the structure of the vibration isolator of FIG. It is the schematic which shows the whole structure of the measuring device of FIG. It is a schematic front view which shows the measuring apparatus which concerns on another embodiment of this invention. It is a schematic front view which shows the other form which can suppress that the vibration from an installation surface is transmitted to a measuring device. It is a schematic front view which shows the other form which can suppress that the vibration from an installation surface is transmitted to a measuring device. It is a schematic front view which shows the other form which can suppress that the vibration from an installation surface is transmitted to a measuring device.

Explanation of symbols

S1 Air chamber T Installation surface 1 Vibration isolator 2 First metal plate 3 Anti-vibration rubber 4 Second metal plate 5 Vibration isolation table 6 Measuring instrument 6a Excitation optical system 6b Measurement optical system 8 Mechanical chopper

Claims (7)

A vibration isolator provided between an installation surface and a measuring instrument for suppressing vibration from the installation surface from being transmitted to the measuring instrument;
A first metal plate installed on the installation surface;
A second metal plate provided on the first metal plate;
An elastic member sandwiched between the first metal plate and the second metal plate, and elastically deformable by receiving vibration from the first metal plate;
The vibration is provided on the second metal plate, and at least a part of the measuring device is placed on an upper surface of the second metal plate, and at least a part is elastically deformed according to vibration from the second metal plate. And a vibration isolation table capable of absorbing
A vibration isolation device, wherein a vibration frequency band absorbed by the first metal plate, the elastic member, and the second metal plate is different from a vibration frequency band absorbed by the vibration isolation table.   The vibration isolation table includes a main body attached to the second metal plate, a placement part on which at least a part of the measuring device is placed, and air provided between the main body part and the placement part. The vibration isolation device according to claim 1, further comprising: a chamber, wherein the vibration is absorbed by a change in volume of the air chamber.   The vibration isolator according to claim 1 or 2, wherein at least the first metal plate of the first metal plate and the second metal plate has a weight larger than that of the measuring device.   A measurement apparatus comprising: the vibration isolation device according to any one of claims 1 to 3; and a measuring device that is at least partially placed on a vibration isolation table of the vibration isolation device. .   The measuring device includes a mechanical chopper for generating intermittent light irradiated to the measurement object, and a measurement unit for measuring a change in the measurement object due to the intermittent light, and the mechanical chopper or the measurement unit The measuring apparatus according to claim 4, wherein one is arranged on the vibration isolation table and the other is arranged separately on the second metal plate.   The measurement apparatus according to claim 5, wherein the mechanical chopper is placed on the second metal plate, and the measurement unit is placed on the vibration isolation table.   The measurement unit is configured to irradiate measurement light onto an irradiation site of the measurement object irradiated with the intermittent light and measure a phase change of the measurement light before and after passing through the irradiation site. The measuring apparatus according to claim 5 or 6.

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