WO2013191683A1

WO2013191683A1 - Vibrometer

Info

Publication number: WO2013191683A1
Application number: PCT/US2012/043113
Authority: WO
Inventors: Wen Tse HSU; Chia-Lin Lee; Pang-Chen KUO
Original assignee: Ardic Instruments Co.; Liou, Albert Ge-Shean
Priority date: 2012-06-19
Filing date: 2012-06-19
Publication date: 2013-12-27

Abstract

The present invention discloses a vibrometer to measure the vibration frequency of an article. The vibrometer can acquire dynamic displacement information and image information of the article simultaneously. The vibrometer is used with a computer system to compute the vibration frequency of the article from the dynamic displacement information and show the image information.

Description

VIBROMETER

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention discloses a vibrometer to measure an article, more particularly to a vibrometer that can acquire vibration frequency information and image information of the article after measurement.

Related Art

Accompanying with the vigorous development of nano-technology, development of mechatronics system has been undertaken toward micro electro -mechanical system (MEMS), the products of which, for example, are gyroscope, accelerometer, MEMS microphone, piezoelectric element, and pressure sensor. During the manufacturing process or design validation test of each product, the physical properties of the product (such as surface static electricity, heat capacity, or vibration frequency) have to be measured for quality control or functional performance verification. However, MEMS device belongs to the order of micrometer such that its physical properties, especially the vibration frequency, is unable to be measured by conventional contact method. Therefore, optical measuring system having nano-scale resolution power has been playing an important role gradually. Currently, beam deflection principle and interferometry principle are applied in the non-contact vibration measurement method adaptable to MEMS device, among which the products applying the principle of interferometry are white light interferometer and Doppler laser interferometer. In addition, astigmatism optical module is also adaptable to MEMS device for nano-scale measurement.

A Taiwanese Patent Gazette No. 1264520 entitled " A System for measuring surface height, angle and its variation of article" discloses a system incorporating astigmatic optical module for measuring height and angle of an article, in which a four-quadrant photodetector is used to convert the measured data into the variations of the height and the angle of the article. Furthermore, an optical path mechanism disclosed in an US Patent Application

No. 20110095210 is formed by the combination of an astigmatic detection system and an optical image system. A light beam is emanated from a light source and is collimated into a parallel beam by a collimating lens. With two beam splitters, the parallel beam passes through an object lens and is focused on the surface of an article to be measured. The light reflected from the article passes through an object lens and is split into an image beam and a measuring beam with a beam splitter, in which the image beam is transmitted through one of the beam splitters and is focused on the image sensing unit of the optical image system by a sensing lens, while the measuring beam is refracted by the above beam splitter and is transmitted through the other beam splitter, a detection lens, and an astigmatic lens in this order and is finally projected on a four-quadrant photodetector so as to produce measuring signals of the article surface. The algorism for handling the measuring signals of the article surface is the same as disclosed in the US7247827. On the other hand, the image sensing unit can acquire the image information on the article surface on the measured area thereof by the image beam projected thereon.

However, the optical path system disclosed in US Patent Application No. 20110095210 has its image sensing unit assembled on a vertical optical axis formed by the beam splitters, the object lens, and the article; and the light signals received is obtained by the action of the object lens and the beam splitters after reflecting from the article. This design of vertical coaxial optical path should take special attention on the calibration of assembled optical path, otherwise the surface image information is prone to skew and error.

The abovementioned prior art are incorporated herein by reference and are regarded as a part of this disclosure. SUMMARY OF THE INVENTION

In view of the abovementioned problems, the inventor of the present invention has conducted much analysis and research on the implementation method and its structure of the above relevant prior art, so as to bring out solutions for the abovementioned problems. Therefore, the main object of the present invention is to provide a vibrometer by which the dynamic displacement information of the article and the image information of the article surface can be obtained synchronously with implementation, so that user can understand immediately the status of the undergoing measurement.

In order to achieve above objects, the inventor of the present invention is mainly to conduct integration on a newly invented measuring system, a loading stage, and a multiaxial adjusting device, so that the vibrometer has feature of sensitive operation in addition to the advantages of synchronous acquirement of the dynamic displacement information of the article and the image information of the article surface that are contained in prior art, so as to increase its overall effect in practical implementation. When implemented in this manner, the demand of miniaturization and easy operation can be fulfilled.

The objects, the technical contents and the expected effect of the present invention will become more apparent from the following description of a preferred embodiment in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective view showing the outline of the present invention.

Figure 2 is a schematic view I showing the structure of the present invention.

Figure 3 is another preferred embodiment of the present invention. Figure 4 is a schematic view II showing the structure of the present invention.

Figure 5 is a schematic view III showing the structure of the present invention.

Figure 6 is a schematic view IX showing the structure of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 is a perspective view showing the outline of the present invention. Referring to Figure 1, the vibrometer 1 of the present invention is formed by the assembly of a measuring system 12, a loading stage 14, and a multiaxial adjusting device 16.

Next, referring to Figure 2 which is a schematic view I showing the structure of the first embodiment of the present invention, the measuring system 12 in the present invention has an optical path formed by several optical members described as below: a light emitting module 121, a first light-splitting unit 122, a refracting unit 123, a second light-splitting unit 124, a lens set 125, a detecting module 126, and an image capture module 127. As shown in the figure, the light emitting module 121 can produce a main light source 1211, and a main projecting optical axis INI is formed along the optical path of the main light source 1211. The first light-splitting unit

122 is located in the optical path of the main projecting optical axis INI, and the first light- splitting unit 122 is formed with a spectroscopic axis IN2. The refraction unit

123 is located behind the first light-splitting unit 122, while the main projecting optical axis INI, in turn, produces a refraction optical axis IN3 after refraction by the refracting unit 123. The second light-splitting unit 124 is located in the optical path of the refraction optical axis IN3 behind the refracting unit 123 and the second light- splitting unit 124 is formed with another spectroscopic axis IN4. The lens set 125 is located in the optical path of the refraction optical axis IN3 behind the second light-splitting unit 124, and the position of the lens set 125 is the end of the overall optical path, where a measuring zone 128 is formed at this end. The detecting module 126 is located in the optical path of the spectroscopic axis IN2 of the first light- splitting unit 122 and is used to convert the reflected light received by the detecting module 126 into dynamic displacement information. The image capture module 127 is disposed in the optical path of the other spectroscopic axis IN4 of the second light- splitting unit 124 and is used to convert the other reflected light received by the image capture module 127 into image information. Further, the image information can be displayed on a display device. In this manner, users can promptly acquire the current status of the undergoing measurement by the generation of both the dynamic displacement information and the image information synchronously with the measuring. In this way, when the measurement is conducted, the main light source 1211 is produced by the light emitting module 121 so as to form a projecting light LI (thick solid line shown in the figure). The projecting light LI propagates forward along the main projecting optical axis INI; then reaching the refracting unit 123 after transmitting through the first light- splitting unit 122; and propagating along the refraction optical axis IN3 after refraction; then reaching the lens set 125 after transmitting through the second light-splitting unit 124; and being projected, after passing through the lens set 125, onto the surface Bl of the article B to be measured so as to conduct measurement. After the abovementioned projecting light LI reaches the surface Bl of the article B disposed in the measuring zone 128, a reflected light RL1 is produced to propagate along the refraction optical axis IN3, and to pass through the second light-splitting unit 124. When passing through the second light-splitting unit 124, a part of the reflected light RL1 is split by the second light- splitting unit 124 into the image capture module 127 (beam RL12 as shown in the figure). The original reflected light RL1 continues its propagation to the refracting unit 123 and propagates along the main projecting optical axis INI after refracting by the refracting unit 123. When passing through the first light- splitting unit 123, a part of the reflected light RL1 is split by the first light- splitting unit 123 into the detecting module 126 (beam RL14 as shown in the figure). Next, after picking up by the image capture module 127, the beam RL12 produced due to the light splitting action is converted to image information which can produce surface image of the article B to be displayed on the display device 2. On the other hand, after picking up by the detecting module 126, the beam RL14 produced due to the light splitting action can produce dynamic displacement information of the surface Bl of the article B. In this manner, when conducting measuring operation, users can synchronously acquire the dynamic displacement information and the image information of the surface Bl of the article B. Furthermore, the dynamic displacement information of the surface Bl of the article B indicates that the changes on the displacement produced on the surface Bl of the article B along the refraction optical axis IN3 will result in the change of the signals of the beam RL14 projecting on the detecting module 126, and so does the dynamic signals. The detecting module 126 transmits the dynamic displacement information having time domain property (that is, the displacement change of the surface Bl of the article B in continuous "vibration") to a computer (not shown) having a arithmetic unit (not shown) and a display device 2, and the dynamic displacement information is converted to a vibration frequency signals of the article B by the operation of the arithmetic unit in coordination with Fourier's transformation.

Figure 3 shows another preferred embodiment of the present invention, in which other relevant members can be incorporated in the optical path of the measuring system 12 for improving the accuracy of the overall measurement of the present invention. Referring to Figure 3, a cylindrical lens 30 is added in between the first light-splitting unit 122 and the detecting module 126, so that the beam RL14, after passing through the cylindrical lens 30, produces astigmatic effect in the projection on the detecting module 126. In this way, the signals of the beam RL14 received by the detecting module 126 can be converted to dynamic displacement information by the astigmatic effect. Furthermore, a collimating lens 40 can be added in between the first light-splitting unit 122 and the refracting unit 123 so that the possible scattering of the projection light LI, formed by the main light source 1211, happened in the projection optical path can be adjusted by the collimating lens 40 so as to allow the projection light LI becoming parallel beam. Furthermore, a third light- splitting unit 129 is also added in between the refracting unit 123 and the second light-splitting unit 124, and the third light-splitting unit 129 is in collocation with an auxiliary light source module 50 which is served as an auxiliary light source for producing a auxiliary light 501. During the process of measurement, the auxiliary light 501 is to supplement the insufficient light source so as to make the overall measurement result become clearer. In other words, the auxiliary light 501 produced by the auxiliary light source module 50 is deflected by the third light- splitting unit 129 located in the optical path of the refraction optical axis IN3, then propagates along the refraction optical axis IN3 after deflection, and passes through the second light-splitting unit 124 and the lens set 125, and is incident on the surface Bl of the article B and its adjacent area. After reflected from the surface Bl, part of the light is split to spectroscopic optical axis IN4 by the second light-splitting unit 124 and is projected to the image capture module 127. In this manner, the light required for actuating the image capture module 127 can be supplemented. Referring again to the figure, in order to improve the clearness of the image taken by the image capture module 127, a filter lens 60 is added in between the image capture module 127 and the second light- splitting unit 124 for filtering out stray light, so as to improve the clearness of the image taken by the image capture module. Furthermore, the lens set 125 can be adjusted to its upper or lower positions (arrow in dashed line as shown in the figure) according to demand, when operators conduct measuring operation, so as to achieve the effect of focal-length adjustment. In this manner, when operators conduct measuring operation, appropriate focal length can be selected in collocation with the adjustment of the position of the lens set 125, so as to conduct the measuring.

In turn, referring to Figure 4, a schematic view (II) showing the structure of the present invention, the loading stage 14 is correspondingly disposed at the measuring zone 128 located at the end of the optical path of the above measuring system 12, so that the article B to be measured can be placed on the loading stage 14 to wait for measurement. As shown in the figure, the loading stage 14 is assembled on a sliding rail device 141 so that the loading stage 14 can displace in the axial direction of the sliding rail device 141. The main purpose is to allow the operators to push the loading stage 14 easily into position, after the article is placed thereon before the measurement is conducted. Further, the loading stage 14 and the sliding rail device 141 as a whole are assembled with a mounting seat 142. Moreover, a vibration source 18 is additionally provided on the loading stage 14. When conducting the measurement, the article B is placed on the vibration source 18 which is served as an external vibration source of the article B for scanning the resonance frequency of the article B. That is to say, when conducting the measurement, the vibration source 18 produces vibrations and excites the article B placed thereon. When the vibration frequency of the vibration source 18 changes, the vibration frequency of the article B also changes. When the vibration frequency of the vibration source 18 is just equal to a resonance frequency of the article B, the amplitude on the surface Bl of the article B will be the maximum, and correspondingly the vibration frequency signal of the article B converted from the dynamic displacement information of the surface Bl of the article B will present a peak value, and the peak value by which the frequency value represents is the resonant frequency of the article B.

Next, referring to Figure 5, a schematic view (III) showing the structure of the present invention, the multiaxial adjusting device 16 has a linking-up seat 161 which is at least assembled with a first axial adjusting bar 162 and a second axial adjusting bar 163. The linking-up seat 161 can produce displacement in two axial direction, for example, X direction (left, right) and Y direction (forward, rearward). Further, a third axial adjusting bar 164 can also added in, so that the linking-up seat 161 can further produce a displacement in third axial direction, for example, Z direction (upward, downward). Moreover, please refer to both Figure 4 and 5, the linking-up seat 161 is assembled with the mounting seat 142 of the loading stage 14 in such a manner to form mutual linking-up relationship. That is to say, when one of the axial adjusting bars (162, 163, 164) is operated, the linking-up seat 161 will displace so as to simultaneously displace the mounting seat 142 of the loading stage 14. This multiaxial adjusting device 16 is very suitable for small-distance fine adjustment, as it can provide fine adjustment operation of relative precise distance for users and then improve operational easiness and handiness of the vibrometer 1. Referring to Figure 6, a schematic view (IV) showing the structure of the present invention, in which the measuring system 12, the loading stage 14, and the multiaxial adjusting device 16 are already combined together. Further, if a housing is added, then the final assembly is shown in Figure 1.

Summing up above, the vibrometer 1 of the present invention is to measure the vibration frequency of an article B disposed on the loading stage 14 by the optical path inside the measuring system 12, and to acquire the dynamic displacement information of the article B and the image information of the surface Bl of the article B synchronously with the measuring operation. Furthermore, in order to facilitate the measuring operation, the present invention further comprises a multiaxial adjusting device 16 which can adjust the relative positions between the article B and the measuring system 12 according to the demand during the measurement of article B. For example, when the measuring system is fixed in position, the position of the article B can be adjusted by the multiaxial adjusting device 16 so that the focal length (the relative distance between the article B and the lens set 125) can effectively adjusted. Based on foregoing, the present invention assuredly can provide a vibrometer that can acquire vibration frequency information and image information of an article to be measured, so that users can understand immediately the status of the undergoing measurement.

While the present invention has been described by a preferred embodiment in conjuction with accompanying drawings, it should be understood the embodiment and the drawings are merely for descriptive and illustrative purpose, not intended for restriction of the scope of the present invention. Equivalent variations and modifications conducted by person skilled in the art without departing from the spirit and scope of the present invention should be considered to be within the scope of the present invention.

Claims

CLAIMS What is claimed is:

1. A vibrometer for measuring the vibration frequency of an article to acquire dynamic displacement information of the article and image information of the article, wherein the vibrometer comprises: a measuring system having a measuring optical path which has a detecting module for acquire the dynamic displacement information of said article, and an image capture module for acquiring the image information of the article, and the measuring optical path having a measuring zone formed at its end; a loading stage for mounting said article to be measured, the loading stage being correspondingly assembled at the measuring zone of the measuring system; and a multiaxial adjusting device having a linking-up seat which is assembled with a first axial adjusting bar and a second axial adjusting bar, the linking-up seat being assembled with the loading stage in linking-up manner so that the loading stage can be linked to displace.

2. The vibrometer as claimed in claim 1, wherein the light measuring optical path has: a light emitting module provided at its start end, the light emitting module including a main light source and a main projecting optical axis being formed along the optical path of the main light source; a first light- splitting unit being located in the optical path of the main projecting optical axis, and the first light-splitting unit being formed with a spectroscopic axis; a refraction unit being located behind the first light-splitting unit, while the main projecting optical axis producing, in turn, a refraction optical axis after refraction by the refracting unit; a second light-splitting unit being located in the optical path of the refraction optical axis behind the refracting unit and the second light-splitting unit being formed with another spectroscopic axis; a lens set being located in the optical path of the refraction optical axis behind the second light-splitting unit; the detecting module being located in the optical path of the spectroscopic axis of the first light-splitting unit and being used to convert the reflecting light received by the detecting module into the dynamic displacement information; and the image capture module being disposed in the optical path of the other spectroscopic axis of the second light-splitting unit and being used to convert the other reflecting light received by the image capture module into the image information.

3. The vibrometer as claimed in claim 2, wherein a cylindrical lens is installed between the first light-splitting unit and the detecting module.

4. The vibrometer as claimed in claim 2, wherein a collimating lens is installed between the first light-splitting unit and the refracting unit.

5. The vibrometer as claimed in claim 2, wherein a third light-splitting unit, in cooperation with an auxiliary optical module, is installed between the refraction unit and the second light-splitting unit, and the auxiliary optical module is capable of generating auxiliary light to be projected onto the third light- splitting unit.

6. The vibrometer as claimed in claim 2, wherein a filter lens is installed between the image capture module and the second light-splitting unit.

7. The vibrometer as claimed in claim 2, wherein the lens set can be adjusted upward or downward according to the requirements during the measurement operation.

8. The vibrometer as claimed in claim 1, wherein a sliding rail device is assembled under the loading stage, and the load stage and the sliding rail device as a wholeare assembled with a mounting seat.

9. The vibrometer as claimed in claim 1, wherein the linking-up seat is assembled with a third axial adjusting bar.

10. The vibrometer as claimed in claim 1, wherein a vibration source is assembled in the loading stage and the article is placed on the vibration source during measurement.