JP6743393B2 - Displacement measuring device - Google Patents

Description

The present invention relates to a displacement measuring device.

Conventionally, by using a quarter-wave plate, only light in a specific polarization direction has been condensed. Thereby, the position of the reflector is specified (for example, refer to Patent Document 1).
[Prior Art Document]
[Patent Document]
[Patent Document 1] Japanese Patent Laid-Open No. 6-221853

On the other hand, it is conceivable to provide a light receiving unit such as a photodiode on the measurement target itself to specify the position of the measurement target. However, when the object is at a high temperature or charged with a high voltage, there is a problem that the electric circuit of the light receiving section does not operate even if the light receiving section is provided on the measurement target.

In a first aspect of the present invention, a displacement measuring device that measures displacement of a measurement target, the displacement measuring device including a light source unit, an optical scanning unit, a reflecting unit, a light receiving unit, and a displacement calculating unit. I will provide a. The optical scanning unit may include an optical scanning device that is rotatable about a predetermined axis. The optical scanning device may reflect the light emitted from the light source unit. The reflector may be provided on the measurement target. The reflecting section may reflect the light reflected from the optical scanning section. The light receiving section may receive the light reflected by the reflecting section. The displacement calculator may calculate the displacement of the measurement target based on the light received by the light receiver. The light source section, the optical scanning section, the light receiving section, and the displacement calculating section may be provided separately from the measurement target.

The reflector may have two or more non-parallel reflecting surfaces.

One of the two or more non-parallel reflecting surfaces may be arranged orthogonal to the other reflecting surface.

The reflecting portion may have one reflecting surface. The light source unit may include a first light source and a second light source. The second light source may be provided at a position where the angle with respect to the reflecting portion is different from the angle of the first light source with respect to the reflecting portion. The optical scanning unit may include a first optical scanning device. The first optical scanning device may reflect the light emitted from the first light source to one reflecting surface. The light receiving section may include a first light receiving element and a second light receiving element. The first light receiving element may receive the light reflected by the first optical scanning device and reflected by one reflecting surface. The second light receiving element may receive the light emitted from the second light source and reflected by one reflecting surface. The displacement calculator calculates the displacement of the measurement target in the first direction and the displacement of the measurement target in the second direction based on the light received by the first light receiving element and the light received by the second light receiving element. You can do it. The second direction may be orthogonal to the first direction.

The optical scanning unit may further include a second optical scanning device. The second optical scanning device may reflect the light emitted from the second light source to one reflecting surface.

The second light receiving element may be provided so as to face one reflecting surface.

The second light receiving element may be a photodiode array in which a plurality of photodiodes are arranged in a plane.

The wavelength of maximum intensity in the first light source may be different than the wavelength of maximum intensity in the second light source.

The displacement calculator may correct the displacement of the measurement target according to the temperature of the measurement target.

One light source in the light source unit may have different peak wavelengths.

One or more of the light scanning unit, the reflecting unit, and the light receiving unit may further include an optical film that reflects or transmits the light emitted from the light source unit.

Note that the above summary of the invention does not enumerate all necessary features of the present invention. Further, a sub-combination of these feature groups can also be an invention.

It is a figure which shows the displacement measuring apparatus 100 in 1st Embodiment. FIG. 4 is a top view of the optical scanning device 22. It is a figure explaining the principle which calculates the displacement z of the measuring object 110 based on the scanning angle (theta). It is a figure which shows the other example of the reflection part 30. It is a figure which shows the displacement measuring apparatus 200 in 2nd Embodiment. It is a figure which shows the displacement measuring apparatus 300 in 3rd Embodiment. It is a figure explaining the wavelength of different maximum intensity. It is a figure which shows the displacement measuring apparatus 400 in 4th Embodiment. 6 is a diagram illustrating an example of correcting the displacement z according to the temperature of the measurement target 110. FIG. It is a figure which shows the example which one light source 12 has a some different peak wavelength. FIG. 6 is a diagram showing an example in which a reflective film 72 is provided on the reflective surface 25 of the optical scanning device 22. It is a figure which shows the example which provides the reflective film 72 on the 1st reflective surface 32. It is a figure which shows the example which provides the transparent film 74 in the 1st light receiving element 42. It is a figure which shows the example which provides the reflection part 30 in the casing 502 of the gas turbine 500. It is a figure which shows the example which provides the reflection part 30 in the transformer 510. It is a figure which shows the example which provides the reflection part 30 in the hoistway 522 of the building 520. FIG. It is a figure which shows the example which provides the reflection part 30 in the bridge 530.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all of the combinations of features described in the embodiments are essential to the solving means of the invention.

FIG. 1 is a diagram showing a displacement measuring device 100 according to the first embodiment. The displacement measuring apparatus 100 of this example measures the displacement z of the measurement target 110 in the Z direction. FIG. 1A is a diagram showing an initial state in which the measurement target 110 is not displaced. On the other hand, FIG. 1B is a diagram showing a state in which the displacement z in the Z direction is generated in the measurement target 110.

In this example, the X direction and the Y direction are orthogonal to each other, and the Z direction is a direction perpendicular to the XY plane. The X direction, the Y direction, and the Z direction form a so-called right-handed system. The Z direction is not necessarily the direction perpendicular to the ground. In this example, the direction in which the measurement target 110 is displaced is described as the Z direction for the purpose of simplifying the description. However, the direction in which the measurement target 110 is displaced may be the X direction or the Y direction. Correspondingly, the displacement measuring apparatus 100 may measure the displacement x or the displacement y of the measuring object 110 in the X direction or the Y direction.

The configuration of the displacement measuring device 100 of this example will be described with reference to FIG. The displacement measuring device 100 includes a light source unit 10, an optical scanning unit 20, a reflecting unit 30, a light receiving unit 40, and a control unit 50. In this example, the light source unit 10, the optical scanning unit 20, the light receiving unit 40, and the control unit 50 are provided apart from the measurement target 110. However, the reflector 30 is provided on the measurement target. The reflector 30 may be provided in direct contact with the measurement target 110. In this example, the first reflecting surface 32 of the reflecting section 30 is provided in direct contact with at least the measurement target 110. In this example, the light receiving unit 40 is not provided on the measurement target 110. Therefore, it is possible to solve the problem that the light receiving unit 40 does not operate even when the object is at a high temperature or is charged with a high voltage.

The shortest straight line distance from the optical scanning unit 20 to the measurement target 110 is defined as a distance d. The distance d is a sufficiently large value with respect to the displacement z of the measurement target 110. As an example, when the distance d is 30 [m] to 50 [m], the displacement z may be several [mm] to several [cm]. The position where the light is projected from the light scanning unit 20 onto the measurement target 110 can be treated as a point. This point is indicated by the projection point P. The measurement target 110 is not a component of the displacement measuring device 100. In order to show this, the measuring object 110 is shown by a dotted line in FIG.

The light source unit 10 has a light source 12. The light source unit 10 of this example has one light source 12. The light source 12 may be a laser light source. The position of the light source 12 of this example is fixed with respect to the optical scanning unit 20.

The optical scanning unit 20 has an optical scanning device 22. The optical scanning unit 20 of this example has one optical scanning device 22. The optical scanning device 22 of this example is a so-called optical MEMS scanner. The optical scanning device 22 has a reflecting surface 25 and a rotating shaft 27. The reflecting surface 25 can rotate on a predetermined rotation axis 27 within a predetermined angle range. For example, the reflecting surface 25 rotates on the rotation axis 27 within an angle range of ±θ with respect to the XY plane. This may be expressed as the reflecting surface 25 vibrates on the rotation axis 27.

The reflecting surface 25 reflects the light emitted from the light source 12. As a result, the light that enters the optical scanning device 22 from the light source 12 is reflected to the measurement target 110. Due to the rotation of the reflecting surface 25, the light reflected by the measurement target 110 is scanned on the measurement target 110.

The reflection unit 30 is fixedly provided on the measurement target 110. Therefore, when the measurement target 110 is displaced in the Z direction, the reflecting section 30 is also displaced along with the measurement target 110 in the Z direction by the same length. The reflector 30 further reflects the light reflected from the optical scanning unit 20. As a result, the reflecting section 30 reflects the light incident on the reflecting section 30 to the light receiving section 40.

The reflector 30 may have two or more non-parallel reflecting surfaces. When using two or more parallel reflecting surfaces, two or more sets of the light source unit 10, the optical scanning unit 20, and the light receiving unit 40 are required. On the other hand, in this example, by using two or more non-parallel reflecting surfaces, the displacement measurement can be performed by the pair of the light source unit 10, the optical scanning unit 20, and the light receiving unit 40. Therefore, the number of parts of the displacement measuring apparatus 100 can be reduced, and thus the cost of the displacement measuring apparatus 100 can be reduced as compared with the case where two or more parallel reflecting surfaces are used.

The reflecting section 30 of the present example has a first reflecting surface 32 parallel to the XY plane and a second reflecting surface 34 parallel to the XY plane. The first reflecting surface 32 is arranged orthogonal to the second reflecting surface 34. The first reflecting surface 32 and the second reflecting surface 34 form an L shape in the YZ plane. Thereby, the reflected light is emitted from the second reflecting surface 34 to the light receiving section 40 in parallel with the incident direction from the optical scanning section 20 to the first reflecting surface 32.

The light receiving unit 40 of this example is arranged in a position close to the optical scanning unit 20 but different from the optical scanning unit 20. For example, on the housing of the optical scanning unit 20, the light receiving element 42 is arranged in a direction substantially the same as the emission direction of light from the optical scanning device 22. As a result, after being emitted from the optical scanning device 22, the light is retroreflected by the reflecting section 30 and enters the light receiving element 42.

In this example, since the incident light from the optical scanning unit 20 is retroreflected by the reflecting unit 30, one set of the light source unit 10, the optical scanning unit 20, and the light receiving unit 40 can be arranged close to each other to make a compact arrangement. .. In addition, since the information from the light source unit 10, the light scanning unit 20, and the light receiving unit 40, which is one set, may be data-processed instead of two sets, there is an effect that the data processing is easier than in the case of two sets. ..

The light receiving section 40 includes a light receiving element 42 and a current/voltage converting section 43 which are connected to each other. The light receiving section 40 of this example has one light receiving element 42 and one current-voltage conversion section 43. The light receiving element 42 may be a photodiode. The light receiving element 42 receives the light reflected by the reflecting section 30.

The light receiving element 42 generates a current in direct proportion to the amount of incident light. That is, when the amount of incident light increases, the current generated by the light receiving element 42 increases, and when the amount of incident light decreases, the current generated by the light receiving element 42 decreases. The current value generated by the light receiving element 42 may be monitored by the controller 50. The timing at which the current value generated by the light receiving element 42 reaches a peak is the timing at which the light retroreflected from the reflecting section 30 enters the light receiving element 42.

When the measurement target 110 is not displaced, it is assumed that the light receiving element 42 exhibits a peak current value at _a predetermined scanning angle θ _a of the optical scanning device 22. In this case, the distance from the projection point P of the light scanning unit 20 in the Y direction to the first reflecting surface 32 is d·tan θ _a . The current generated by the light receiving element 42 is converted into a voltage signal in the current/voltage converter 43. The voltage signal is output to the control unit 50.

The controller 50 has a displacement calculator 52 and a driver 54. The displacement calculator 52 may obtain information on the scanning angle θ of the optical scanning device 22 and the voltage signal from the current-voltage converter 43 in real time. Thereby, the displacement calculator 52 can identify the position of the reflector 30 on the measurement target 110. In this example, the position of the reflection unit 30 specified by the displacement calculation unit 52 does not have to be an accurate absolute position. The position of the reflection unit 30 specified by the displacement calculation unit 52 may be any position that can specify the relative position before and after the displacement of the measurement target 110. In this example, when the measurement target 110 is at the initial position, the reflecting surface 25 has a scanning angle θ _a .

The drive unit 54 drives the optical scanning device 22. The drive unit 54 applies an AC power supply to the optical scanning unit 20. As a result, the reflecting surface 25 of the optical scanning device 22 rotates within the range of the scanning angle ±θ. The drive unit 54 can increase the variation range of the scanning angle θ of the reflecting surface 25 by increasing the voltage amplitude of the AC power supply. The drive unit 54 can also reduce the variation range of the scanning angle θ of the reflecting surface 25 by reducing the voltage amplitude.

Next, a method of calculating the displacement z in the Z direction that has occurred in the measurement target 110 will be described with reference to FIG. The displacement calculator 52 calculates the displacement z of the measurement target 110 based on the light received by the light receiver 40. For example, in the initial state where the measurement target 110 is not displaced, the current value of the light receiving element 42 shows a peak at the scanning angle θ _a . Next, it is assumed that the current value of the light receiving element 42 has a peak at the scanning angle θ _b when the displacement z in the Z direction occurs in the measurement target 110. However, θ _b is an angle larger than θ _a . In this case, the displacement z of the measurement target 110 can be expressed as z=d·(tan θ _b −tan θ _a ). In this way, the light receiving element 42 can specify the scanning angle θ at which the current peak appears, and the displacement can be calculated using this scanning angle θ.

The measurement target 110 may vibrate in the X direction and the Y direction. The vibration of the measuring object 110 in the X direction or the Y direction may cause noise when measuring the displacement z of the measuring object 110 in the Z direction. Therefore, the displacement measuring apparatus 100 may include a laser Doppler vibrometer in order to detect the presence or absence of vibration in the measurement target 110 with the laser Doppler vibrometer. The laser Doppler vibrometer can detect the velocity and displacement of vibration at a point irradiated with laser based on the Doppler effect. The measurement result of the laser Doppler vibrometer may be output to the displacement calculator 52. The displacement calculator 52 may ignore the displacement z in the Z direction when the measurement target 110 is vibrating. Thereby, the accuracy of the calculation result of the displacement z can be further improved.

FIG. 2 is a top view of the optical scanning device 22. The optical scanning device 22 of this example is a comb-teeth type optical MEMS scanner. The optical scanning device 22 can be formed by etching an SOI substrate. The optical scanning device 22 has a fixed portion 26, a driving portion 28, and comb teeth 29 in addition to the reflecting surface 25 and the rotating shaft 27.

The reflecting surface 25 may further have a metal layer such as aluminum having a thickness of 100 nm on the surface silicon layer (active layer) of the SOI substrate. The metal layer functions as a mirror. A pair of rotating shafts 27 is provided in the X direction with the reflecting surface 25 interposed therebetween. One end of the rotary shaft 27 is fixed to the reflecting surface 25, and the other end is fixed to the fixed portion 26. A plurality of comb teeth 29 are provided at the ends of the reflecting surface 25 in the ±Y direction. The reflecting surface 25, the rotating shaft 27, and the comb teeth 29 on the reflecting surface 25 side are continuously and integrally formed by etching the surface silicon layer (active layer) of the SOI substrate.

A set of drive units 28 is provided in the Y direction with the reflecting surface 25 interposed therebetween. The drive unit 28 and the fixed unit 26 are continuously and integrally formed via the back surface silicon layer (substrate layer) of the SOI substrate. The drive unit 28 is provided with a plurality of comb teeth 29. The drive unit 28 and the comb teeth 29 on the drive unit 28 side are continuously and integrally formed by etching the surface silicon layer (active layer) of the SOI substrate. The comb teeth 29 on the drive unit 28 side and the comb teeth 29 on the reflection surface 25 side are arranged so as to mesh with each other. However, they are arranged so as not to contact each other. As a result, the interdigitated comb teeth 29 can form a capacitance.

Electrode pads are provided at the ends of the fixed portion 26 in the ±X directions. A predetermined DC voltage may be applied to the electrode pad of the fixed portion 26. Electrode pads are provided on the ends of the drive unit 28 in the ±X directions. A predetermined AC voltage may be applied to the electrode pads of the driving unit 28. Thus, the electrostatic force between the comb teeth 29 on the reflecting surface 25 side and the comb teeth 29 on the driving unit 28 side allows the reflecting surface 25 to rotate with respect to the rotating shaft 27 within a predetermined angle range. In FIG. 2, the electrode pad is shown by a rectangular frame at the ends of the fixed portion 26 and the drive portion 28.

FIG. 3 is a diagram illustrating the principle of calculating the displacement z of the measuring object 110 based on the scanning angle θ. FIG. 3A is a diagram showing a temporal change of the scanning angle θ, and FIG. 3B is a diagram showing a temporal change of the photoelectric conversion current I in the light receiving element 42. The vertical axis of FIG. 3A is the scanning angle θ [degrees], and the vertical axis of FIG. 3B is the photoelectric conversion current I [a. u. ]. In FIGS. 3A and 3B, the horizontal axis represents time, which is common to both.

The cycle of the scanning angle θ in this example is 1 [msec]. That is, the reflecting surface 25 of this example vibrates at 60 [kHz]. Since the measurement target 110 is, for example, a building or the like, the reflection surface 25 may be regarded as having a vibration frequency sufficiently higher than that of the measurement target 110. Therefore, the displacement measuring device 100 is not affected by the vibration of the measuring object 110 in the Z direction. Therefore, the displacement measuring apparatus 100 of this example can measure the Z-direction vibration of the measurement target 110 in addition to the Z-direction displacement of the measurement target 110.

The photoelectric conversion current I in FIG. 3B periodically peaks in accordance with the change over time of the scanning angle θ in FIG. In this example, at the scanning angle θ=3.2 [degrees], the photoelectric conversion current I shows peaks at t1, t2, t3, and t4. At t1, t2, t3, and t4, most light from the light source unit 10 is retroreflected by the light receiving unit 40.

The displacement calculator 52 can obtain information on the temporal change of the scanning angle θ from the optical scanning device 22. The displacement calculator 52 of this example calculates the scanning angle θ from the initial scanning angle θ _i of the reflecting surface 25 of the optical scanning device 22 and the change in the capacitance of the comb teeth 29. As a result, the displacement calculator 52 can know the information about the temporal change of the scanning angle θ in real time. In the optical scanning device 22, the electrostatic capacity formed by the comb teeth 29 of the reflecting surface 25 and the comb teeth 29 of the driving unit 28 increases or decreases according to the scanning angle θ of the reflecting surface 25. In addition, the displacement calculator 52 can obtain the time information indicating the peak of the photoelectric conversion current I in real time. Thereby, the displacement calculator 52 can specify the scanning angle θ at which the photoelectric conversion current I shows a peak. Therefore, in this example, the displacement measuring device 100 can be configured at low cost with a simple configuration without using an optical element such as a half mirror or a splitter.

The displacement calculator 52 may specify the scanning angle θ at which the photoelectric conversion current I exhibits a peak, from one current peak measurement result. Instead of this, the displacement calculator 52 may specify the scanning angle θ at which the photoelectric conversion current I exhibits a peak, from the current peak measurement results of a plurality of times.

The displacement calculator 52 of this example specifies the scanning angle θ at which the photoelectric conversion current I peaks from the current peak measurement results of 100 times. Specifically, each scanning angle θ corresponding to the current peak of 100 times may be averaged. As a result, the noise during measurement is leveled, and the accuracy of the displacement z of the measurement target 110 in the Z direction can be further improved. In addition, in this example, 1 [msec] is required for two current peak measurements, and therefore 50 [msec] is required for 100 current peak measurements. The current peak measurement 100 times can be quickly performed in 1 [sec] or less.

FIG. 4 is a diagram showing another example of the reflecting section 30. The reflector 30 in this example is a corner cube. FIG. 4 is a cross-sectional view of a corner cube having a first reflective surface 32 and a second reflective surface 34 that are two or more non-parallel reflective surfaces. Also in this example, since the light receiving unit 40 is not provided in the measurement target 110, the problem that the light receiving unit 40 does not operate even when the object is at high temperature or charged with a high voltage is solved. can do.

FIG. 5 is a diagram showing a displacement measuring device 200 according to the second embodiment. The reflecting section 30 of the present example has the first reflecting surface 32 as one reflecting surface rather than two or more non-parallel reflecting surfaces that realize retroreflection. Note that, in this example, the arrangement of XYZ is different from that of the first embodiment due to this. The Z direction in this example is the direction from the optical scanning unit 20 toward the measurement target 110. However, the point that the displacement in the Z direction is measured is the same as in the first embodiment.

The light source unit 10 of this example includes a first light source 12 and a second light source 14. Further, the optical scanning unit 20 has a first optical scanning device 22 and a second optical scanning device 24. Further, the light receiving section 40 includes a first light receiving element 42 and a current/voltage converting section 43, and a second light receiving element 44 and a current/voltage converting section 45. With this configuration, the displacement calculation unit 52 of the present example, based on the light received by the first light receiving element 42 and the light received by the second light receiving element 44, the measurement target 110 in the Z direction as the first direction. And the displacement y of the measuring object 110 in the Y direction as the second direction are calculated.

The light emitted from the first light source 12 is reflected on the first reflecting surface 32 in the first optical scanning device 22. Then, the light receiving element 42 receives the light reflected by the first reflecting surface 32. The point that the displacement calculator 52 specifies the scanning angle θ ₁ of the reflecting surface 25 in the optical scanning device 22 from the timing when the photoelectric conversion current I peaks is the same as in the first embodiment. However, in this example, the method of calculating the displacement z is different.

It is assumed that the scanning angle at which the photoelectric conversion current I has a peak when there is no displacement z is θ _1a . Further, it is assumed that the scanning angle at which the photoelectric conversion current I peaks when the displacement z occurs is θ _1b . Note that θ _1a is an angle larger than θ _1b . In this case, the displacement z is calculated by z=d·(1/tan θ _1a −1/tan θ _1b ).

The second light source 14 is provided at a position where the angle β with respect to the reflecting portion 30 is different from the angle α of the first light source 12 with respect to the reflecting portion 30. In this example, the angle with respect to the reflection unit 30 means the angle formed by the Z direction and the incident light from the light source. The angle β formed by the second light source 14 and the Z direction may be sufficiently smaller than the angle α formed by the first light source 12 and the Z direction. For example, the angle β may be larger than 0 [degrees] and a few [degrees] or less. It is preferable that the angle β is closer to 0 [degree]. Further, in this example, the scanning angle θ ₂ of the optical scanning device 24 is smaller than the scanning angle θ ₁ of the optical scanning device 22.

The second optical scanning device 24 reflects the light emitted from the second light source 14 to the first reflecting surface 32. In this example, the light reflected from the optical scanning device 24 enters substantially perpendicularly to the XY plane. The second light receiving element 44 is provided so as to face the first reflecting surface 32. In this example, the second light receiving element 44 and the first reflecting surface 32 are provided so as to face each other in the Z direction for measuring the displacement. The second light receiving element 44 receives the light reflected by the first reflecting surface 32. In this example, the second light source 14, the second optical scanning device 24, and the second light receiving element 44 can be used to detect the deviation of the first reflecting surface 32 in the X and Y directions. For example, the displacement x of the measurement target 110 in the X direction and the displacement y of the measurement target 110 in the Y direction can be detected.

By outputting the displacement y of the measurement target 110 in the Y direction to the displacement calculation unit 52, the displacement calculation unit 52 may ignore the displacement z in the Z direction when the displacement y occurs in the measurement target 110. For example, the scanning angle θ ₁ of the first optical scanning device 22 at the timing when the displacement y is measured may not be used for calculating the displacement z. Thereby, the accuracy of the calculation result of the displacement z can be further improved. Note that the frequency of the scanning angle θ ₂ in the second optical scanning device 24 is higher than the frequency of the scanning angle θ ₁ in the first optical scanning device 22 in order to grasp the timing at which the displacement y occurs more accurately. Good.

FIG. 6 is a diagram showing a displacement measuring device 300 according to the third embodiment. This example differs from the second embodiment in the arrangement and configuration of the second light source 14 and the second light receiving element 44. The second light source 14 of this example is incident on the first reflecting surface 32 via the semi-transmissive film 16. Thereby, the light incident from the second light source 14 can be made to enter completely perpendicular to the XY plane.

The second light receiving element 44 is provided so as to face the first reflecting surface 32. In this example, the second light receiving element 44 is a photodiode array in which a plurality of photodiodes are arranged in a plane. The second light receiving element 44 and the first reflecting surface 32 may face each other by providing the light receiving surface configured by the photodiode array in parallel with the XY plane. The photodiode array of this example may include the current-voltage converter 45.

The photodiode array of this example has 5×5 photodiodes in the XY plane. 5×5 is an example for simplifying the description, and the number of photodiodes may be 5×5 or more. Then, it may be set in advance so that the incident light from the first reflecting surface 32 when there is no displacement in the X direction and the Y direction is incident on the photodiode in the third row and the third column. That is, when there is no displacement in the X and Y directions, the photodiode in the third row and third column shows the peak of the photoelectric conversion current I.

On the other hand, when the measurement target 110 is displaced in the X direction, the photodiodes at different positions in the X direction of the photodiode array show the maximum photoelectric conversion current I. Similarly, when the measurement target 110 is displaced in the Y direction, the photodiodes at different positions in the Y direction of the photodiode array show the maximum photoelectric conversion current I. In this way, the displacement of the first reflecting surface 32 in the X direction and the Y direction can be detected by detecting the positional change of the photodiode showing the maximum photoelectric conversion current.

The displacements in the X direction and the Y direction may be detected using the ratio of the currents of the plurality of adjacent photodiodes. For example, if the ratio of the photoelectric conversion currents I in two photodiodes adjacent in the X direction, that is, D _3,3 :D _4,3 when D _X,Y is 3:7, D _{3, The} light reflected from the first reflecting surface 32 may be applied to the position where the distance between ₃ and D _4,3 is divided into 7:3. Similarly in the Y direction, the position of the reflected light from the first reflecting surface 32 may be specified.

FIG. 7 is a diagram for explaining different maximum intensity wavelengths. In this example, the maximum intensity wavelength λ ₁ of the first light source 12 is different from the maximum intensity wavelength λ ₂ of the second light source 14. As a result, the influence of the first light source 12 on the second light receiving element 44 and the influence of the second light source 14 on the first light receiving element 42 can be reduced. Therefore, the accuracy of displacement measurement can be improved as compared with the case where the wavelength of the same maximum intensity is used.

FIG. 8 is a diagram showing a displacement measuring device 400 according to the fourth embodiment. In this example, the temperature measuring unit 60 is provided on the measurement target 110 to measure the temperature of the measurement target 110. Although the temperature measuring unit 60 in this example is a contact type, the temperature measuring unit 60 may be a non-contact type. That is, the temperature measurement unit 60 may measure the temperature of the measurement target 110 apart from the measurement target 110.

When the measurement target 110 becomes hot, it is assumed that the reflection part 30 is deformed due to thermal expansion. The angle of light incident on the light receiving element 42 may change due to the deformation of the reflecting section 30. Therefore, the displacement calculator 52 may correct the displacement of the measurement target 110 according to the temperature of the measurement target 110. This example is different from the first embodiment in this respect. It should be noted that measuring the temperature of the measurement target 110 and correcting the displacement of the measurement target 110 may be applied to the second embodiment and the second embodiment.

FIG. 9 is a diagram illustrating an example in which the displacement z is corrected according to the temperature of the measurement target 110. FIG. 9A is a diagram showing a state in which the reflecting section 30 has not been thermally expanded. FIG. 9B is a diagram showing a change in reflected light when the reflecting section 30 thermally expands. FIG. 9C is a diagram illustrating that the scanning angle θ is corrected when the reflecting section 30 thermally expands.

Since FIG. 9A corresponds to the description of FIGS. 1 to 3, description thereof will be omitted. As shown in FIG. 9 (b), the temperature of the measurement object 110 by changing from _{T 0} to _{T 0} + [Delta] T, the reflective portion 30 is thermally expanded. At this time, the reflection angles on the first reflecting surface 32 and the second reflecting surface 34 change as compared with FIG. 9A. As a result, the photoelectric conversion current I does not show a peak at the timing of the scanning angle θ _a . The first reflecting surface 32, the second reflecting surface 34, and the reflected light before thermal expansion are shown by dotted lines, and these after thermal expansion are shown by solid lines.

After the thermal expansion, it is assumed that the photoelectric conversion current I has a peak at the timing of the scanning angle θ _c as shown in FIG. 9C. In this example, θ _c is an angle smaller than θ _a . In this case, if originally place to be the length d · tan .theta _a, due to the thermal expansion of the reflection portion 30 d · tanθ _a problem that is calculated as (<d · tanθ _c) occurs.

Therefore, the displacement calculator 52 has a correction table in advance that the scanning angle θ at which the photoelectric conversion current I peaks changes from θ _a to θ _c when the temperature of the measurement target 110 increases by ΔT. Good. The displacement calculation unit 52 has the scanning angle θ corresponding to the temperature change of the reflection unit 30 as a correction table in advance, so that the displacement of the measurement target 110 can be corrected according to the temperature of the measurement target 110. As a result, even if the reflecting section 30 thermally expands and contracts, the displacement can be accurately measured. Note that the amount of deformation and the shape of deformation during thermal expansion differ depending on the shape and material of the reflecting section 30, and thus the correction table may be provided for each reflecting section 30.

FIG. 10 is a diagram showing an example in which one light source 12 has a plurality of different peak wavelengths. The peak wavelength in this example means a wavelength at which the emission intensity has a maximum value. Note that one light source 14 may have a plurality of different peak wavelengths. The displacement measuring devices 100, 200, 300 and 400 may be used outdoors. For example, in the usage environment, when a strong red color is present due to the setting sun, the light source 12 emitting red color cannot be used. Further, in the usage environment, when a strong blue color exists due to external light such as a light, the light source 12 that emits blue color cannot be used.

The light source 12 of this example has peak wavelengths of λ ₁ , λ ₂ and λ ₃ . For example, the peak wavelength λ ₁ is 380 nm or more and less than 495 nm, the peak wavelength λ ₂ is 495 nm or more and less than 590 nm, and the peak wavelength λ ₃ is 590 nm or more and 750 nm or less. As a result, it is possible to avoid a situation in which the light source 12 cannot be used and the displacement measuring device 100 or the like does not function depending on the usage environment.

By applying the example described in FIG. 7 to this example, the light source 12 and the light source 14 may have different peak wavelengths at least partially. In one example, if light source 12 has peak wavelengths of λ ₁ and λ ₂ , then light source 14 may have peak wavelengths of λ ₂ and λ ₃ . Further, when the light source 12 has peak wavelengths of λ ₁ , λ ₂ and λ ₃ , the light source 14 may have a peak wavelength λ ₄ different from any of λ ₁ , λ ₂ and λ ₃ .

11A to 11C are examples in which one or more of the light scanning unit 20, the reflecting unit 30, and the light receiving unit 40 have an optical film that reflects or transmits the light emitted from the light source unit 10. As described above, the displacement measuring device 100 and the like may not be able to use a specific wavelength band depending on the usage environment. Therefore, in this example, a plurality of peak wavelengths are emitted from the light source 12, and an unusable wavelength is blocked by an optical film. Thereby, the wavelength to be used can be selected according to the usage environment. Therefore, the accuracy of the displacement measurement can be maintained regardless of the use environment.

FIG. 11A is a diagram showing an example in which the reflection film 72 is provided on the reflection surface 25 of the optical scanning device 22. The reflection film 72 has a function of reflecting only a specific wavelength band and not reflecting other wavelength bands. FIG. 11B is a diagram showing an example in which the reflective film 72 is provided on the first reflective surface 32. In the example of FIG. 11B, the reflective film 72 does not affect the rotation of the optical scanning device 22. Further, the reflective film 72 can be easily installed on the reflective portion 30. Therefore, it is easier to implement than the example of FIG. 11A.

FIG. 11C is a diagram showing an example in which the transparent film 74 is provided on the first light receiving element 42. The transmission film 74 has a function of transmitting only a specific wavelength band and not equivalent to other wavelength bands. Also in the example of FIG. 11C, the transmission film 74 does not affect the rotation of the optical scanning device 22. Further, the transparent film 74 can be easily installed on the first light receiving element 42. Therefore, it is easier to implement than the example of FIG. 11A. Note that any two of the examples of FIGS. 11A, 11B, and 11C may be combined.

12A to 12D show an example in which the displacement measuring device 100 or the like is applied. FIG. 12A is a diagram showing an example in which the reflecting section 30 is provided on the casing 502 of the gas turbine 500. The compressor 503 compresses air and sends the compressed air to the combustor 501. The combustor 501 burns air and fuel to move the gas turbine 500. The gas turbine 500, the combustor 501, and the compressor 503 are covered with a casing 502. The casing 502 has a diameter L _Y of 3 m and a length L _Z in the vertical direction of 10 m, for example.

In this example, the casing 502 is provided with the reflecting portion 30, and the displacement of the casing 502 in the Z direction is measured. Since the temperature of the gas turbine 500 reaches 1,000° C. or higher, the casing 502 also has a considerably high temperature. In this example, by measuring the displacement of the casing 502, the abnormality of the entire generator can be grasped in advance.

FIG. 12B is a diagram illustrating an example in which the transformer 510 is provided with the reflection unit 30. The transformer 510 is a device that handles a voltage of thousands [V] to hundreds of thousands [V]. A steel tower 512 for providing a power transmission line and a lightning protection line is provided on a side portion and an upper portion of the transformer 510. In this example, the abnormality of the transformer 510 can be grasped in advance by providing the reflecting portion 30 on the surface of the transformer 510 and measuring the displacement of the transformer 510 in the Z direction. The reflection part 30 may be provided on the surface of the steel tower 512 to measure the displacement of the steel tower 512 in the Z direction.

FIG. 12C is a diagram showing an example in which the reflecting section 30 is provided in the hoistway 522 of the building 520. The building 520 may have a height of several tens [m] to several hundreds [m]. A hoistway 522, which is a space in which an elevator 524 can move up and down, is provided inside the building 520 of this example. In this example, the optical scanning unit 20 and the light receiving unit 40 are provided above the elevator 524. It should be noted that although the control unit 50 is not shown for the sake of easy viewing of the drawing, the control unit 50 may also be provided above the elevator 524. On the other hand, the reflector 30 may be provided at the top of the hoistway 522. By performing the displacement measurement with the elevator 524 stopped, the displacement of the building 520 in the Z direction can be measured.

FIG. 12D is a diagram showing an example in which the reflecting section 30 is provided on the bridge 530. The bridge 530 of this example is a suspension bridge type and has a main girder 532 and a main tower 534. The main girder 532 and the main tower 534 are fixed by a cable 536. The reflector 30 of this example is provided at the top of the main tower 534. In this example, the displacement of the main tower 534 in the Z direction can be measured. The displacement of the main girder 532 in the Z direction may be measured by providing the reflection part 30 on the main girder 532.

Although the present invention has been described above using the embodiment, the technical scope of the present invention is not limited to the scope described in the above embodiment. It is apparent to those skilled in the art that various changes or improvements can be added to the above-described embodiment. It is apparent from the description of the scope of claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

The execution order of each process such as operation, procedure, step, and step in the devices, systems, programs, and methods shown in the claims, the specification, and the drawings is "preceding" or "prior to". It should be noted that the output of the previous process can be realized in any order unless the output of the previous process is used in the subsequent process. The operation flow in the claims, the specification, and the drawings is described using “first,” “next,” and the like for the sake of convenience, but it is essential that the operations are performed in this order. Not a thing.

10...Light source part, 12...light source, 14...light source, 16...semitransmissive film, 20...light scanning part, 22...light scanning device, 24...light scanning device, 25...reflective surface, 26..Fixing part, 27..rotating shaft, 28..driving part, 29..comb teeth, 30..reflecting part, 32..first reflecting surface, 34..second reflecting surface, 40..・Light receiving part, 42・・Light receiving element, 43・・Current-voltage converting part, 44・・Light receiving element, 45・・Current-voltage converting part, 50・・Control part, 52・・Displacement calculating part, 54・・Drive part , 60・・Temperature measuring part, 72・・Reflective film, 74・・Transmissive film, 100・・Displacement measuring device, 110・・Measuring object, 200・・Displacement measuring device, 300・・Displacement measuring device, 400・・Displacement measuring device, 500 ··· Gas turbine, 501·· Combustor, 502·· Casing, 503·· Compressor, 510·· Transformer, 512·· Steel tower, 520·· Building, 522·· Hoistway, 524 ..Elevators, 530..Bridges, 532..Main girders, 534..Main towers, 536..Cables

Claims (8)

A displacement measuring device for measuring displacement of a measuring object,
A light source section,
An optical scanning unit that has a light scanning device that reflects light emitted from the light source unit and that can rotate on a predetermined axis,
A reflector provided on the measurement target, which reflects the light reflected from the optical scanning unit,
A light receiving portion for receiving the light reflected from the reflecting portion,
A displacement calculation unit that calculates the displacement of the measurement target based on the light received by the light receiving unit,
The light source section, the optical scanning section, the light receiving section and the displacement calculating section are provided separately from the measurement target ,
The reflecting portion has one reflecting surface,
The light source unit,
A first light source,
A second light source provided at a position where an angle with respect to the reflecting portion is smaller than an angle of the first light source with respect to the reflecting portion;
Have
The optical scanning unit,
A first optical scanning device that reflects the light emitted from the first light source to the one reflecting surface;
A second optical scanning device that reflects the light emitted from the second light source to the one reflecting surface;
Have
The light receiving unit,
A first light receiving element that receives the light reflected by the first optical scanning device and reflected by the one reflecting surface;
A second light receiving element for receiving the light reflected by the second optical scanning device and reflected by the one reflecting surface;
Have
The displacement calculation unit,
Based on the light received by the second light receiving element, it is detected whether or not the displacement of the measurement target in the first direction parallel to the one reflecting surface has occurred,
When the displacement of the measurement target in the first direction does not occur, the displacement of the measurement target in the second direction orthogonal to the one reflecting surface is calculated based on the light received by the first light receiving element. to <br/> displacement measuring device. A displacement measuring device for measuring displacement of a measuring object,
A light source section,
An optical scanning unit that has a light scanning device that reflects light emitted from the light source unit and that can rotate on a predetermined axis,
A reflector provided on the measurement target, which reflects the light reflected from the optical scanning unit,
A light receiving portion for receiving the light reflected from the reflecting portion,
A displacement calculation unit that calculates the displacement of the measurement target based on the light received by the light receiving unit;
Equipped with
The light source section, the optical scanning section, the light receiving section and the displacement calculating section are provided separately from the measurement target,
The reflecting portion has one reflecting surface,
The light source unit,
A first light source,
A second light source provided at a position where an angle with respect to the reflecting portion is vertical.
Have
The optical scanning unit has a first optical scanning device that reflects the light emitted from the first light source to the one reflecting surface,
The light receiving unit,
A first light receiving element that receives the light reflected by the first optical scanning device and reflected by the one reflecting surface;
A second light receiving element for receiving the light emitted from the second light source and reflected by the one reflecting surface;
Have
The displacement calculation unit,
Based on the light received by the second light receiving element, it is detected whether or not the displacement of the measurement target in the first direction parallel to the one reflecting surface has occurred,
When the displacement of the measurement target in the first direction does not occur, the displacement of the measurement target in the second direction orthogonal to the one reflecting surface is calculated based on the light received by the first light receiving element. Do
Displacement measuring device. The second light receiving element, the displacement measuring apparatus according to claim 1 or 2 provided opposite to the one reflecting surface. The displacement measuring device according to claim 2 , wherein the second light receiving element is a photodiode array in which a plurality of photodiodes are arranged in a plane. The wavelength of maximum intensity in the first light source, the displacement measuring apparatus according to the wavelength of maximum intensity from different to any one of claims 1 to 4 in the second light source. The displacement calculating unit, in accordance with the temperature of the measurement target, the displacement measuring apparatus according to any one of claims 1 to 5 for correcting the displacement of the measurement target. One of the light source in the light source unit, a displacement measurement apparatus according to any one of claims 1 to 6 having a plurality of different peak wavelengths. The optical scanning unit, the reflective portion and one or more of the light receiving portion, displacement measurement according to any one of claims 1 to 7 further comprising an optical film that reflects or transmits light irradiated from the light source unit apparatus.

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