WO2023120170A1

WO2023120170A1 - Vibration analysis system, vibration analysis device, and vibration analysis method

Info

Publication number: WO2023120170A1
Application number: PCT/JP2022/044972
Authority: WO
Inventors: 亜張; 未来飯森
Original assignee: 国立大学法人東京農工大学
Priority date: 2021-12-22
Filing date: 2022-12-06
Publication date: 2023-06-29

Abstract

The purpose of the present invention is to provide a vibration analysis system, a vibration analysis device, and a vibration analysis method that enable vibration analysis of samples that generate minute vibrations while keeping down construction costs.　In this vibration analysis system, a differential interference microscope is used to irradiate a sample driven by a voltage signal of a prescribed frequency with pulsed light modulated in phase synchronization with the voltage signal and capture a microscopic image of the sample, the differential interference microscope being capable of emitting pulsed light split through a differential interference prism and measuring the protrusion shapes and depression shapes of a sample surface in a prescribed measurement range.

Description

Vibration analysis system, vibration analysis device, and vibration analysis method

The present disclosure relates to a vibration analysis system, a vibration analysis device, and a vibration analysis method.

Conventionally, there are technologies for vibration analysis of micro-vibration devices such as MEMS (Micro Electro Mechanical Systems) devices. A MEMS device has a total length in units of mm (millimeters) and its parts in units of μm (micrometers). Therefore, the scale of vibration analysis of such a MEMS device becomes nanometer (nm) or smaller.

There are mainly two types of methods used for vibration analysis of MEMS devices. One is a technique using a laser Doppler vibrometer based on the optical Doppler effect. Although this method can realize high-sensitivity vibration measurement, the number of points that can be measured simultaneously is limited to one point, and two-dimensional vibration analysis is difficult.

Another method is to use a double-beam interference microscope such as a Michelson interferometer. Several methods have been proposed and put into practical use as techniques for two-dimensional vibration analysis of MEMS devices based on this method. See Patent Document 1 and Non-Patent Documents 1 to 3 for the technique of this method. Patent Document 1 is Japanese National Publication of International Patent Application No. 2016-501373. Non-Patent Document 1 is "A. Bosseboeuf, et al., presented at the Microsystems Metrology and Inspection, 1999." Non-Patent Document 2 is "J. Reed, et al., Journal of Microelectromechanical Systems 16, 668 (2007)." Non-Patent Document 3 is "I. Shavrin, et al., Opt. Express 21, 16901 (2013)." The features common to this method include the following points. The first common point is that the surface shape of the MEMS device is measured using an interference microscope, and the two-dimensional height of the MEMS device surface is measured by interference between the reference light and the measurement light. The second common point is that a pulsed light source that is phase-locked to the vibration of the MEMS device is used to irradiate the element of the MEMS device, and the vibration shape is analyzed by sampling the high-speed vibration.

However, the prior art of two-dimensional vibration analysis of MEMS devices using conventional interference microscopes had the problem that it was difficult to adjust the optical system. Therefore, there is a problem that high-precision optical-mechanical parts are required for constructing the vibration analysis system, resulting in high cost. In addition, the prior art has a problem that the measurement range is narrow, and there is a problem that sufficient measurement cannot be performed.

An object of the present disclosure is to provide a vibration analysis system, a vibration analysis apparatus, and a vibration analysis method that can perform vibration analysis of a sample that generates minute vibrations while suppressing construction costs.

The vibration analysis system of the present disclosure irradiates a pulsed light branched through a differential interference prism, and uses a differential interference microscope capable of measuring the protrusion shape and depression shape of the sample surface in a predetermined measurement range. The sample driven by the voltage signal is irradiated with the pulsed light modulated in phase synchronization with the voltage signal, and a microscopic image of the sample is captured.

The vibration analysis apparatus of the present disclosure includes a differential interference microscope capable of irradiating a pulsed light branched through a differential interference prism and measuring the protrusion shape and depression shape of the sample surface in a predetermined measurement range, and a sample with a predetermined frequency. , a light source for irradiating the sample with the pulsed light modulated in phase synchronization with the voltage signal, and an optical system for capturing a microscope image of the sample.

The vibration analysis method of the present disclosure uses a differential interference microscope capable of measuring the shape of protrusions and depressions on the surface of the sample in a predetermined measurement range, and irradiates the sample with pulsed light branched through a differential interference prism. , applying a voltage signal of a predetermined frequency to the sample, irradiating the sample with the pulsed light modulated in synchronization with the voltage signal, and capturing a microscope image of the sample. include.

It is a simple schematic diagram of the method of the vibration analysis using the conventional interference microscope. FIG. 4 is a schematic diagram for comparing methods of vibration analysis using a differential interference microscope; It is an image of a bent MEMS beam observed with a normal microscope. It is an image of a bent MEMS beam observed with a Michelson interference microscope. It is an image of a bent MEMS beam observed with a differential interference microscope. It is a figure which shows the structure of the vibration analysis system of this embodiment. It is a graph explaining the high-speed vibration by a pulse light source. It is a graph explaining the high-speed vibration by a pulse light source. It is a microscope image. 4 is a graph of light intensity; FIG. 4 is a diagram showing a measurable frequency range; It is a figure which shows the pulse width of illumination light. It is a block diagram which shows the hardware constitutions of a control part. It is a figure which shows the flow of a process of a measurement program. It is an example of a measurement result of vibration amplitude. It is the measurement result of the mode shape. It is the measurement result of the mode shape. It is the measurement result of the mode shape.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

Before describing the embodiments of the present disclosure, regarding the vibration analysis of MEMS devices, which are micro-vibration devices, (1) the problem that the optical system is difficult to adjust and (2) the measurement range is narrow. explain the problem. In the following description, a case where the method of vibration analysis of the present embodiment is applied using a MEMS device as a sample will be described as an example, but the present invention is not limited to this. The method of vibration analysis of this embodiment enables measurement on a scale of nm units. Therefore, the vibration analysis method of the present embodiment can be similarly applied to other micro-vibration devices having minute sizes such as mm or μm in the height direction and in the horizontal direction, similarly to the MEMS device. be. In addition, the method of vibration analysis of the present embodiment is applicable not only to micro-vibration devices, but also to substances, cells, and the like, as long as the samples are capable of generating minute vibrations.

Regarding (1), since the conventional interferometer utilizes the interference fringes of the reference light and the measurement light, it is necessary to precisely align the surface of the device with the reference mirror. The height of the sample must be adjusted with an accuracy of several tens of nanometers, and the tilt angle of the sample surface must be 0.01° or less. Such settings require very difficult optical alignments and require high precision opto-mechanical components. As a result, the cost associated with the optical system has increased. In addition, since the vibration received from the environment has a large effect on the stability of the interference fringes, strict vibration isolation was required. Therefore, the conventional vibration analysis system for MEMS devices has a problem of high construction costs.

Regarding (2), in conventional two-dimensional vibration analysis, the maximum value of measurable displacement is smaller than a quarter of the wavelength of the irradiated light (generally about 100 to 200 nm). was not within a sufficient measurable range in many studies such as Furthermore, if there is a structure with a large stepwise phase change on the surface of the MEMS device, there is a possibility that it cannot be measured accurately.

In order to solve these two problems, a vibration analysis system using a differential interference microscope is constructed in place of the conventional interference microscope, and two-dimensional vibration analysis of MEMS devices is performed.

FIG. 1 (FIGS. 1A and 1B) is a simple schematic diagram for comparing a vibration analysis method using a conventional interference microscope and a vibration analysis method using a differential interference microscope. As shown in FIG. 1A, in the conventional technique using an interference microscope (A), a reference mirror is used to reflect pulsed light to measure interference fringes. On the other hand, in the method using a differential interference microscope according to the present embodiment shown in FIG. 1B, a differential interference prism is used to branch the pulsed light without using a reference mirror.

In (A) the vibration analysis method using a conventional interference microscope, the configuration includes an interference microscope (Ma), a camera (Mb), a light source (Mc), and a MEMS device (Md). In the interference microscope (Ma), the MEMS device (Md) is irradiated with pulsed light (mc1) emitted from the light source (Mc) via the lens (ma1), the beam splitter (ma2), and the objective lens (ma3). is used as measurement light, and the reference light is reflected by the reference mirror (ma4). Thereby, the interference fringes of the phase difference that change according to the unevenness of the sample are measured. In the method of vibration analysis using the differential interference microscope of this embodiment of (B), there are a differential interference microscope (Ma2), a camera (Mb), a light source (Mc), and a MEMS device (Md) as configurations. Without using the reference mirror (ma4), the differential interference prism (ma5) is used to split the pulsed light into two beams, which are irradiated onto the sample. A small shift in the lateral direction of the two beams of light is called a shear amount. The amount of shear is determined by the differential interference prism and the objective lens. For example, when an Olympus differential interference prism U-DICR and an objective lens LMPlanFL10x are combined, the shear amount is approximately 2.5 μm. When there is such a difference in the optical paths, the intensity of the light is modulated and appears as interference fringes.

　When using a differential interference contrast microscope, there are the following advantages. A differential interference contrast microscope does not use a reference beam, so it has the advantage of not requiring complicated adjustments between the reference beam and the measurement beam. In addition, in a differential interference contrast microscope, all the interference light is reflected from the surface of the sample, so the noise caused by environmental vibration and light, as well as the influence of the tilt of the sample, is greatly reduced, and no special anti-vibration or light shielding is required. There are advantages. In addition, measurement with a differential interference contrast microscope has the advantage that there is almost no limit to the total amount of displacement since the deviation of displacement is measured. It has the advantage that the measuring range is more than ten times larger than that of the Michelson interference microscope.

Figure 2 (Figures 2A, 2B, and 2C) compares the images of the bent MEMS beam observed with a normal microscope, a Michelson interference microscope, and a differential interference contrast microscope. The MEMS beam is a MEMS device with a double-end beam structure. (a) of FIG. 2A is an image observed with a normal microscope, and cannot show the surface shape of the bent MEMS beam in the portion (a1). FIG. 2B (b) is an image observed with a conventional Michelson interference microscope, in which the bending shape of the MEMS beam is indicated by interference fringes. However, even if the tilt angle of the MEMS device is adjusted to a very small angle of 0.05°, the interference fringes are strongly affected by the tilt angle. The (b1) portion is the interference fringes due to bending, the (b2) portion is the interference fringes due to the inclination, and the (b3) portion is the interference fringes due to the electrode. Furthermore, if the measurement optical path length constantly changes due to the vibration of the sample, the condition of zero optical path length difference, which is essential for generating interference fringes, cannot be maintained, making long-term measurement extremely difficult. On the other hand, the image observed by the differential interference microscope in (c) of FIG. 2C is very stable without being affected by the small tilt angle of the MEMS device. Although the tilt of the device was not adjusted at all, the change in the light intensity due to the bending of the MEMS beam in the portion (c1) was clearly observed, and the tilt of the device and the electrode on the surface as in (b) There is very little "background interference".

From the above comparison between conventional interference microscopes and differential interference microscopes, a vibration analysis system with the following advantages can be realized by using a differential interference microscope.

Conventional interference microscopy requires the sample surface to be perfectly aligned with the reference plane. On the other hand, by adopting a differential interference microscope, almost no optical adjustment is required because only the reflected light from the sample surface is used for interference. Therefore, complicated adjustment of optical interference (zero point/tilt) becomes unnecessary, thereby improving convenience.
In addition, since differential interference contrast microscopes use only reflected light from the sample surface, environmental vibrations are less likely to affect the interference fringes compared to conventional techniques. Therefore, it is insensitive to vibration, and does not require a vibration isolating table for providing anti-vibration performance. Furthermore, a commercially available differential interference contrast microscope can be used, which is cheaper than a dedicated interference microscope. Therefore, the cost required to configure the vibration analysis system can be suppressed.
In addition, the measurement displacement range is increased (10 times or more) compared to the conventional technology, and it is possible to measure a sample with a complicated surface.
Furthermore, since an expensive and precise mechanical adjustment system is not required, differential interference contrast microscopes are less expensive than dedicated dual-beam interference microscopes and have cost advantages.

The configuration of the vibration analysis system according to the embodiment of the present disclosure will be described below.

Fig. 3 shows the configuration of the vibration analysis system of this embodiment. As shown in FIG. 3, the vibration analysis system 1 includes a differential interference microscope 10, a digital camera 12, a light source 14 (pulse-modulated LED or laser light source), a function generator 16, and a controller . In this configuration, the vibration analysis system 1 observes the MEMS device 20, which is the sample to be observed. Note that the vibration analysis system 1 is configured as the vibration analysis apparatus of the present disclosure by including all of these configurations.

Each functional part of the configuration of the vibration analysis system 1 functions as follows. (1) The differential interference contrast microscope 10 visualizes information on the surface of the MEMS device on the nm scale. (2) The digital camera 12 captures an image recording the interference pattern of the differential interference microscope 10 . (3) The light source 14 emits periodic pulsed light (illumination light) synchronized with the driving voltage of the MEMS device. The vibration analysis system 1 samples high-speed MEMS vibrations caused by pulses. (4) the function generator 16 provides phase-synchronized drive voltages to the pulse modulated LED 12 and the MEMS device 20; (5) The control unit 18 is a computer, includes analysis software and programs, and calculates the amplitude and vibration mode shape of the MEMS device 20 by controlling the measurement process. Each functional unit will be described below.

The differential interference microscope 10 includes a beam splitter 10a, a polarizing plate 10b, a differential interference prism 10c, and an objective lens 10d. The beam splitter 10 a is installed so as to direct the pulsed light (Pu) incident from a lens (not shown) toward the MEMS device 20 . The polarizing plate 10b converts the pulsed light (Pu) into polarized light. The differential interference prism 10c splits the pulsed light (Pu1) incident through the polarizing plate 10b into two lights (Pu2). In the following description, when distinguishing before and after branching, the pulsed light before branching is (Pu1), and the pulsed light, which is the two light after branching, is (Pu2). do. The objective lens 10d irradiates the MEMS device with the two split lights (Pu2). Note that the configuration of the differential interference contrast microscope 10 is not limited to this, and may be configured appropriately according to the design of the microscope. The differential interference microscope 10 irradiates the MEMS device 20 with pulsed light (Pu2) branched via a differential interference prism (10c), and is configured to measure the unevenness (protrusion shape and depression shape) of the surface of the MEMS device 20. If it is The measurement range of unevenness is usually 1 nm to several thousand nm, preferably 1 nm to 1000 nm. The parameter that determines the measurement range of the unevenness is the differential displacement caused by the unevenness, and the parameter of the differential displacement caused by the unevenness is about 0.05 nm to 60 nm.

The digital camera 12 is attached to the differential interference microscope 10 and captures a microscopic image of the MEMS device 20 through the differential interference microscope 10 . Digital camera 12 may be any color or monochrome CMOS or CCD camera. Digital camera 12 is an example of an optical system for capturing microscopic images of samples of the present disclosure.

Here, the principle of measurement by the vibration analysis system 1 will be explained. The vibration analysis system 1 using the differential interference microscope 10 equipped with the digital camera 12 can observe the movement of the MEMS device 20 in principle. However, the frame rate of most digital cameras is on the order of tens of Hz, which is much slower than the operable frequency band of MEMS devices (tens of kHz to tens of MHz). FIG. 4 (FIGS. 4A and 4B) shows graphs for explaining the high-speed vibration caused by the pulse light source. As shown in (a) of FIG. 4A, the light source 14 (pulse-modulated LED or laser light source) emits pulsed light (Pu) phase-locked with the excitation signal of the MEMS device 20 . Since the vibration of the MEMS device 20 is at the same frequency as the excitation signal, the pulsed light (Pu) is also synchronized with the MEMS vibration and the phase difference therebetween can be modulated. θ in (a) indicates a phase difference. When the MEMS device 20 vibrates and deviates from the equilibrium position, the shape of the surface of the MEMS device 20 changes and the light intensity obtained by the differential interference microscope 10 is modulated. By irradiating such modulated pulsed light (Pu), a microscopic image can be captured at a specific phase of vibration of the MEMS device 20 . Further, by modulating the phase of the pulsed light (Pu) to be irradiated, the entire vibration can be measured. FIG. 5 (FIGS. 5A and 5B) shows a microscope image and a graph of light intensity. The image in (a) of FIG. 5A is a microscope image of the MEMS device 20 and the vibration measurement point (a1). The light intensity of (a1) is measured. Since the phase changes from 0° to 1080° in the graph of (b) of FIG. 5B, it can be seen that the light intensity changes periodically due to the vibration of the MEMS device 20 .

The light source 14 uses a pulse-modulated LED or laser light source whose pulse width satisfies a predetermined measurable frequency band of the resonator associated with the MEMS device 20 . The principle of pulse width applied to the light source 14 is explained below.

Ideally, a narrow pulse of light is used to sample the resonant motion of the MEMS device 20 . Since the measurement of the vibrational motion is averaged over the time that the pulsed light is incident, increasing the pulse width reduces the modulation of the light intensity due to the vibration. FIG. 6 (FIGS. 6A and 6B) shows the measurable frequency range and the pulse width of illumination light. (a) of FIG. 6A is a graph showing the frequency bandwidth of optical intensity modulation by vibration. The frequency bandwidth (a1) is 1/(30ns*2)=about 17MHz. The pulse width ΔT of the light source 14 should be less than half the period T of the cavity of the MEMS device 20 (T/2). Therefore, the measurable frequency bandwidth is given by equation (1) below.
Frequency bandwidth=1/(2Δt) (1)

(b) of FIG. 6B is a graph showing the pulse width of the red LED (light source 14) used in the vibration analysis system 1. FIG. As shown in (b), Δt can achieve a pulse width of approximately 30 ns, which corresponds to a frequency bandwidth of up to 16 MHz. Further, by using a commercially available LED having a frequency bandwidth of 70 MHz for the light source 14, a higher measurement frequency can be achieved.

The function generator 16 outputs (applies) two synchronous voltage signals, one voltage signal (vs1) for driving the MEMS device (vs1) and the other voltage signal (vs2) for the pulse light of the light source 14 ( Pu) is used for modulation. Therefore, the function generator 16 must be able to output voltage signals of at least two channels. In this embodiment, a device capable of outputting arbitrary signals of 25 MHz for two channels is used as the function generator 16 . It should be noted that 240 MHz signal output is also possible when a higher-level device is used. Function generator 16 is an example of a signal source that applies a voltage signal of a predetermined frequency to the sample of the present disclosure.

The control unit 18 is a computer that executes various controls related to the vibration analysis system 1 . The control unit 18 controls each of the imaging of the microscope image by the digital camera 12, the output of the voltage signal by the function generator 16, and the calculation of the amplitude using the microscope image. By controlling the function generator 16 by the control unit 18, the driving voltage and driving frequency of the resonator of the MEMS device 20 are set by the voltage signal output from the function generator 16, and the phase of the pulsed light (Pu) emitted from the light source 14 is set. set the sweep of This allows the vibration of the MEMS device 20 to have a specific phase. The driving voltage causes the MEMS device 20 to vibrate. As described in the principle of measurement above, the light intensity obtained by the differential interference microscope 10 is modulated by the change in the shape of the surface of the MEMS device 20 that occurs when the MEMS device 20 is displaced from the vibration equilibrium position of the MEMS device 20. be done. As such, the control unit 18 causes the digital camera 12 to capture a microscopic image for each phase as a specific phase of the MEMS device 20 . Also, the control unit 18 measures the entire vibration from the microscopic image for each phase. As for the mode of measurement, it is possible to perform measurement using two measurement programs, which will be described later.

FIG. 7 is a block diagram showing the hardware configuration of the control unit 18. As shown in FIG. As shown in FIG. 7, the control unit 18 includes a CPU (Central Processing Unit) 111, a ROM (Read Only Memory) 112, a RAM (Random Access Memory) 13, a storage 114, an input unit 115, a display interface (I/F) 116 and a communication interface (I/F) 117 . Each component is communicatively connected to each other via a bus 119 .

The CPU 111 is a central processing unit that executes various programs and controls each section. That is, the CPU 11 reads a program from the ROM 112 or 1114 and executes the program using the RAM 13 as a work area. The CPU 111 performs various kinds of arithmetic processing related to the above control according to programs stored in the ROM 12 or the storage 114 . In this embodiment, the ROM 112 or storage 114 stores programs.

The ROM 112 stores various programs and various data. The RAM 113 temporarily stores programs or data as a work area. The storage 114 is configured by a storage device such as a HDD (Hard Disk Drive) or an SSD (Solid State Drive), and stores various programs including an operating system and various data.

The input unit 115 includes a pointing device such as a mouse and a keyboard, and is used for various inputs. The display interface 116 is, for example, a liquid crystal display, and displays various information. The display interface 116 may employ a touch panel system and function as the input unit 115 . The communication interface 117 is an interface for communicating with other devices such as terminals, and uses standards such as Ethernet (registered trademark), FDDI, and Wi-Fi (registered trademark), for example.

Two measurement programs that can be executed by the control unit 18 will be described. As a flow of processing common to the two measurement programs, FIG. 8 shows the flow of processing of the measurement program.

A first measurement program measures the resonance frequency of the MEMS device 20 . As shown in FIG. 8, in step S100, the CPU 111 sets the drive voltage for the resonator of the MEMS device 20. FIG. In step S<b>102 , the CPU 111 sets the driving frequency range of the resonator of the MEMS device 20 . In step S104, the CPU 111 sets sweep parameters according to the drive frequency range and the phase of the pulsed light to be irradiated, and sweeps to each phase. Since the amplitude takes the maximum value at the time of resonance, the frequency of resonance of the MEMS device 20 is obtained using the calculated frequency function of the amplitude. That is, there are two sweep parameters for the first program, the set range of drive frequency and phase. It sweeps at each set drive frequency and the phase for each drive frequency. In step S106, the CPU 111 captures an image of the surface of the MEMS device 20 with the digital camera 12 and obtains a microscope image showing resonance in each phase. Then, in step S108, the CPU 111 calculates the vibration amplitude at the driving frequency by using the microscope image showing the resonance in each phase as the calculation of the measurement object.

The microscope image is controlled so that at least three phases (0°, 120°, 240°, etc.) are captured during one cycle. By increasing the number of phases to be measured, the signal-to-noise ratio can be improved. It should be noted that the measurement time also becomes longer as the number of phases increases. FIG. 9 shows vibration amplitude measurement results plotting resonance spectra of the MEMS beam measured when different drive voltages are applied to the MEMS device 20 . The measured amplitude is the differential displacement of measuring point (a1) in FIG. 5 caused by vibration. Excitation voltages are 20 mV, 40 mV, 60 mV, 80 mV, 100 mV. From the measurement results, it can be seen that the resonance frequency of the MEMS beam is approximately 696 kHz. It is also shown that increasing the driving voltage increases the frequency due to the nonlinear vibration of the MEMS beam, and the nonlinear vibration of the MEMS device 20 can also be analyzed by measurement.

The second measurement program measures the two-dimensional resonance mode shape of the MEMS device 20 . Since the flow is the same as that of the first measurement program, only steps with different differences will be described. In the second measurement program, the CPU 111 sets the drive frequency of the MEMS device 20 to the resonance frequency of the MEMS device 20 in step S102. In step S104, the CPU 111 sets sweep parameters according to the drive frequency set to the resonance frequency and the phase of the pulsed light to be irradiated, and sweeps to each phase. In step S108, the CPU 111 calculates the resonance mode shape from the difference image of the vibration mode as the calculation of the measurement target using the microscope image showing the resonance in each phase.

In the second measurement program, the signal-to-noise ratio of the measurement can be improved by averaging multiple frames of the captured microscope image. FIG. 10 (FIGS. 10A, 10B, and 10C) shows measurement results of mode shapes. The shape of the first bending mode of the measured MEMS device is shown in (a) of FIG. 10A. A simulation for comparison is shown in (b) of FIG. 10B. Comparing FIGS. 10A(a) and 10B(b), it can be confirmed that the measured results are in excellent agreement with the simulation results. The measurement result of (a) of FIG. 10A is the difference in the mode shape of the vibration of the MEMS device 20, that is, the gradient of the displacement during vibration. In general, the slope of the displacement allows determination of the resonance mode, but the actual displacement can also be derived. Integrating the (a) difference result of FIG. 10A, the actual mode shape of (c) of FIG. 10C can be obtained. This also agrees well with the simulation result of (b) of FIG. 10B. Therefore, the second measurement program of the control unit 18 can analyze the two-dimensional shape of the resonance mode of the MEMS device 20 with high sensitivity.

As described above, according to the vibration analysis system 1 of the present embodiment, it is possible to reduce the construction cost and perform vibration analysis of a sample that generates minute vibrations.

In addition, the vibration analysis system 1 can be used for analysis such as dynamic resonance analysis and static displacement measurement. These play an important role in processes such as characterization, operation confirmation, and failure analysis of the MEMS device 20 .

Although the vibration analysis system 1 described above has been described as a stand-alone configuration having each configuration with respect to the differential interference contrast microscope 10, it is not limited to this. Such a stand-alone configuration is an example of the vibration analysis device of the present disclosure. In the practical application of the technology of the present disclosure, the vibration analysis system 1 is compact, easy to use, inexpensive, and has high performance, so it can be used for research and development of the MEMS device 20 . Therefore, the vibration analysis system 1 can also be developed as an additional module of the differential interference contrast microscope 10. FIG. Since most of the cost of the vibration analysis system 1 is the differential interference microscope 10, if the vibration analysis function of the control unit 18 is added to the existing differential interference microscope 10 through joint research with a microscope manufacturer, the vibration analysis system 1 Overall costs can be further reduced. Also, digital camera 12, light source 14, and function generator 16 may be additional modules as well. Modularization in this way is also effective in disseminating the method of the present disclosure through the existing sales channels of microscope manufacturers.

It should be noted that the present disclosure is not limited to the above-described embodiments, and various modifications and applications are possible without departing from the gist of the present invention.

The disclosure of Japanese Patent Application No. 2021-208457 filed on December 22, 2021 is incorporated herein by reference in its entirety. All publications, patent applications and technical standards mentioned herein are to the same extent as if each individual publication, patent application and technical standard were specifically and individually noted to be incorporated by reference. incorporated herein by reference.

1 vibration analysis system 10 differential interference microscope 12 digital camera 14 light source 16 function generator 18 controller 20 MEMS device

Claims

Using a differential interference microscope capable of irradiating a pulsed light branched through a differential interference prism and measuring the protrusion shape and depression shape of the sample surface in a predetermined measurement range,
irradiating a sample driven by a voltage signal of a predetermined frequency with the pulsed light modulated in phase synchronization with the voltage signal;
capturing a microscopic image of the sample;
vibration analysis system.
　The vibration analysis system according to claim 1, wherein the sample is a micro-vibration device whose size in the height direction and the width direction is in units of millimeters or micrometers.
The vibration analysis system according to claim 1 or 2, wherein a pulse-modulated LED or laser light source whose pulse width satisfies a predetermined measurable frequency band of the resonator related to the sample is used as the light source of the pulsed light.
Including a control unit that performs predetermined control,
By the control unit, the imaging of the microscope image by the camera, the driving of the micro-oscillating device that is the sample by the output of the voltage signal by the function generator, the modulation of the pulsed light, and the calculation of the amplitude using the microscope image. 3. The vibration analysis system according to claim 1 or 2, wherein the control for
In the control,
By setting the driving voltage and the driving frequency of the resonator of the micro-oscillating device according to the voltage signal output from the function generator, and setting the sweep of the phase of the pulsed light to be irradiated, the micro-oscillating device vibrates. Let be a particular phase, and
light intensity obtained by the differential interference microscope is modulated by a change in the shape of the surface of the micro-oscillating device that occurs when the micro-oscillating device is displaced from an equilibrium position due to vibration of the micro-oscillating device;
causing the camera to capture the microscope image for each phase;
5. The vibration analysis system of claim 4, wherein the total vibration is measured from the phase-by-phase microscopic images.
In the control, the drive frequency is set to the resonance frequency of the micro vibration device;
6. The vibration analysis system according to claim 5, wherein in the measurement, the vibration amplitude at the resonance frequency is measured as the amplitude calculation using the microscope image.
In the control, the drive frequency is set to the resonance frequency of the micro vibration device;
6. The vibration according to claim 5, wherein, in the measurement, the resonance mode shape is measured from the difference image of the vibration mode of the micro vibration device in the microscopic image at the resonance frequency as the calculation regarding the amplitude using the microscopic image. analysis system.
a differential interference microscope capable of irradiating a pulsed light branched through a differential interference prism and measuring the protrusion shape and depression shape of the sample surface in a predetermined measurement range;
a signal source that applies a voltage signal of a predetermined frequency to the sample;
a light source that irradiates the sample with the pulsed light modulated in phase synchronization with the voltage signal;
an optical system for capturing a microscope image of the sample;
Vibration analysis equipment with
9. The vibration analysis apparatus according to claim 8, wherein the sample is a micro-vibration device with dimensions in millimeters or micrometers in the height and width directions.
The vibration analysis device according to claim 8 or 9, wherein the light source includes a light emitting diode or a laser light source.
Including a control unit that performs predetermined control,
By the control unit, the imaging of the microscope image by the camera, the driving of the micro-oscillating device that is the sample by the output of the voltage signal by the function generator, the modulation of the pulsed light, and the calculation of the amplitude using the microscope image. 10. The vibration analysis apparatus according to claim 8 or 9, wherein the control for
irradiating the sample with pulsed light branched via a differential interference prism using a differential interference microscope capable of measuring the shape of protrusions and depressions on the surface of the sample within a predetermined measurement range;
applying a voltage signal of a predetermined frequency to the sample;
irradiating the sample with the pulsed light modulated in synchronization with the voltage signal;
capturing a microscopic image of the sample;
vibration analysis methods, including