WO2016208049A1

WO2016208049A1 - Laser light position control device and measuring device

Info

Publication number: WO2016208049A1
Application number: PCT/JP2015/068443
Authority: WO
Inventors: 幸修田中
Original assignee: 株式会社日立製作所
Priority date: 2015-06-26
Filing date: 2015-06-26
Publication date: 2016-12-29
Also published as: JP6199002B2; JPWO2016208049A1

Abstract

Provided is a laser light position control device applicable to measurement of concentration distribution of particulate matter in the exhaust gas in a pipe, and capable of producing scanning laser light with a simple structure. The laser light position control device comprises: a first oscillation unit for generating first laser light; a first detection unit for detecting the laser light; first and second lenses arranged opposite each other; a first optical axis scanning unit between the first oscillation unit and the first lens; a second optical axis scanning unit between the second lens and the first detection unit; a first control unit for controlling the first optical axis scanning unit; a second control unit for controlling the second optical axis scanning unit; and a scanning command unit for providing the first control unit and the second control unit with control information. The first detection unit detects the laser light through the first optical axis scanning unit, the first and second lenses, and the second optical axis scanning unit. The second control unit controls the second optical axis scanning unit on the basis of the control information from the scanning command unit to the first optical axis scanning unit and the detection signal from the first detection unit.

Description

Laser light position control device and measuring device

The present invention relates to a laser beam position control device and a measurement device.

The abstract of Patent Document 1 includes “an optical beat signal generating unit 1 that generates an optical beat signal, an optical branching unit 2 that branches the optical beat signal into n channels, and an n-channel light input from the optical branching unit 2. An optical delay circuit 3 that independently adjusts and outputs the delay amount of the beat signal, and terahertz wave radiating elements that receive the optical beat signal from the optical delay circuit 3 and emit a terahertz wave are arranged in an array. The phase of the terahertz wave emitted from the terahertz wave radiating element is controlled by controlling the delay amount of the n-channel optical beat signal output from the terahertz wave radiation source 6 and the optical delay circuit 3, and thereby the terahertz wave radiation And a control unit 9 that controls the direction of the terahertz wave emitted from the source 6.

JP2007-103997A

In conventional fluoroscopic imaging of a sample using electromagnetic waves of several tens of GHz to several THz, the sample was irradiated with a focused beam of electromagnetic waves and the sample itself was mechanically moved to scan the focused beam. Therefore, the scanning speed is limited by a mechanical operation, and there is a problem that a long time is required for fluoroscopic imaging. Therefore, Patent Document 1 has been proposed as means for scanning the focused beam in order to increase the speed of fluoroscopic imaging of the sample using the focused beam. In Patent Document 1, a focused beam is scanned using a phased array antenna. In the present invention, when laser light is generated by difference frequency mixing using two condensing beams having different wavelengths, the phase difference of the condensing beam is shifted by using an optical phase shifter for each array element. Scanning is performed by indirectly tilting the wavefront of the focused beam.

However, in Patent Document 1, an optical phase shifter is used for each array element. However, when the scale of the array is increased, it is necessary to use a large number of phase shifters corresponding to the number of elements. There is a problem that the scale and cost of the system will increase.

The present invention has been made in view of the above, and an object thereof is to provide a laser beam position control device capable of controlling the position of a laser beam with a simple structure.

The above object can be achieved by the invention described in the claims. For example, a first oscillation unit that generates a first laser beam, a first detection unit that detects the first laser beam, a first lens and a second lens that are arranged to face each other. Two lenses, a first optical axis scanning unit that scans an optical axis of the first laser light located between the first oscillation unit and the first lens, and the second lens A second optical axis scanning unit that scans the optical axis of the first laser beam located between the first detector and a first control unit that controls the first optical axis scanning unit; A second control unit that controls the second optical axis scanning unit; a first control unit; and a scanning instruction unit that provides control information to the second control unit, and the first detection unit. Detects the first laser beam through the first optical axis scanning unit, the first lens, the second lens, the second optical axis scanning unit, and A control unit configured to control the second optical axis scanning unit based on the control information from the scanning instruction unit to the first optical axis scanning unit and a detection signal of the first detection unit; This is a laser beam position control device.

According to the present invention, a laser beam position control device capable of controlling the position of a laser beam with a simple structure is provided.

The figure which showed the structure of the collection collection measuring device of PM of the filter which concerns on Example 1. FIG. FIG. 3 is a diagram illustrating a configuration of a galvanometer mirror according to the first embodiment. FIG. 3 is a diagram illustrating a relationship between four light receiving units of the detector according to the first embodiment and laser light. FIG. 3 is a diagram illustrating a relationship between two light receiving units of the detector according to the first embodiment and laser light. FIG. 3 is a diagram illustrating a configuration of a light receiving unit of a detector according to Embodiment 1. The figure showing the structure of the collection collection measuring device of PM of the filter concerning Example 2. FIG. FIG. 6 is a diagram illustrating a relationship between a light receiving unit of a detector according to a second embodiment and main and sub laser beams. The figure showing the structure of the collection collection measuring device of PM of the filter concerning Example 3. FIG. FIG. 10 is a flowchart showing a PM concentration calculation method and filter distribution measurement switching according to the third embodiment. The figure showing the structure of the structure measuring apparatus of the water distribution measuring apparatus contained in the paper which concerns on Example 4. FIG. FIG. 6 is a diagram illustrating a configuration of a galvanometer mirror according to a fourth embodiment.

FIG. 1 illustrates the configuration of a repair distribution measuring device for particulate matter (PM) contained in the exhaust gas filter of this embodiment. The frequency of the electromagnetic wave emitted by the oscillating unit 3 is, for example, a frequency that passes through a non-hydrogen bonding substance and is easily absorbed by the carbon component and organic solvent component of the exhaust gas particulate component, for example, 0.1 THz to 3.0 THz. Use wavebands. The terahertz wave has a property of transmitting to some extent to semiconductors, ceramics, paper, etc., absorbing to water, and reflecting to metal. For piping, select a material that emits the terahertz wave collected from the oscillation part as laser light and transmits this laser light to some extent, or a material that transmits terahertz light only to the part of the oscillation part and the photodetector to some extent Keep it as

FIG. 1 shows the configuration of a filter PM collection distribution measuring apparatus according to a first embodiment of the present invention. The PM measuring system of the filter 2 of this embodiment includes an oscillating unit 3, a galvano mirror 5, a scanner lens 7, a scanner lens 8, a galvano mirror 6, a detector 4, and a controller 23. This embodiment is characterized in that three-dimensional imaging of the PM accumulation amount of the filter can be performed. Further, the position of the galvanometer mirror is generally obtained by indirectly detecting it with an angle detector. In this case, there is no compensation in which the position of the galvanometer mirror completely matches the position indicated by the angle detector.

On the other hand, as described in the present embodiment, it is also a feature that the position of the galvanometer mirror can be directly detected by detecting the positional deviation of the laser beam by the detector 4. Further, laser light emitted from the following oscillating unit 3 is converted into laser light having S-polarized light and P-polarized light at a constant light quantity ratio by a polarizing element.

In this embodiment, the controller 3 controls the oscillating unit 3 and the detector 4, and the laser light emitted from the oscillating unit 3 reflects the galvano mirror 5 and enters the filter 2 in the engine piping. The laser light that has passed through the filter 2 enters the detector 4 through the scanner lens 7, the scanner lens 8, and the galvanometer mirror 6. Here, the galvanometer mirror 5 can rotate around the rotation axis of the rotary drive actuator 10 to change the angle. The rotation angle of the rotary drive actuator 10 is detected by the angle detector 9, and the detected signal is input to the arithmetic circuit (A) 18.

The arithmetic circuit (A) 18 generates a drive signal necessary for the galvano mirror 5 to perform positioning control at a predetermined angle. Based on this control signal, the control unit (A) 11 sends a drive control signal to the rotary drive actuator 10. Is sent out. For example, the arithmetic circuit (A) 18 generates a drive signal for reciprocating the galvanometer mirror 5 within a predetermined angle range, for example, 30 deg, and the control unit (A) 11 controls the rotary drive actuator 10 to thereby control the laser. The light can be scanned and the filter 2 can be passed uniformly.

At this time, by detecting the signal of the detector 4, it is possible to detect the absorption rate of PM deposited on the filter 2. For example, it is possible to image a change in the amount of PM accumulated in the filter over time. it can. Furthermore, in the present embodiment, the PM 2 is disposed on the filter 2 for the purpose of measuring PM accumulated on the filter. However, for example, it may be disposed on the exhaust part of the vehicle as a PM detection device.

Further, in the present embodiment, the laser light transmitted through the filter 2 is incident on the detector 4 through the scanner lens 8 and the galvanometer mirror 6, but positional deviation or the like becomes a problem in the detector using a semiconductor element. . For this reason, for example, the amount of light reduction may be learned in accordance with the incident angle to the semiconductor element and corrected using the learned amount. This correction optical control means will be described below.

In order to correct the positional deviation at the detector 4, the galvanometer mirror 6 can rotate around the rotation axis of the rotary drive actuator 13 and change the angle. The rotation angle of the rotation drive actuator 13 is detected by the angle detector 12 and input to the arithmetic circuit (B) 19. In addition, a mechanism for detecting the optical axis deviation angle by the position sensor 15 provided in the detector 4 for correcting the optical axis positional deviation is provided to compensate for the optical axis positional deviation generated by the positional deviation signal generation circuit 17. Is also input to the arithmetic circuit (B) 19.

The arithmetic circuit (B) 19 generates a drive signal necessary for controlling the galvanometer mirror 6 to a predetermined position by the rotational position control, and the control unit (B) 14 based on the control signal, the rotational drive actuator 13 A drive control signal is sent to. With such correction optical control means, the optical axis can be controlled to a predetermined position of the detector 4 by performing an optical axis position correction operation. Here, the galvano mirror 6 needs to be driven in cooperation with the galvano mirror 5. Therefore, the synchronization control unit 16 sends the position profile of the galvano mirror 5 to the arithmetic circuit (A) 18 and receives the position information of the galvano mirror 5 from the angle detector 9 through the arithmetic circuit (A) 18. 16 sends the position profile of the galvanometer mirror 6 to the arithmetic circuit (B) 19, and the galvanometer mirrors 5 and 6 realize a synchronized scanning operation.

Here, for example, the misalignment signal generation circuit 17 synchronizes the galvanometer mirror 6 by sending a signal indicating that the galvanometer mirror 6 is controlled within a predetermined angle range, for example, a static angle width within ± 1 mdeg, to the synchronization control unit 16. Realize control. Next, the galvanometer mirrors 5 and 6 will be described.
2A shows the configuration of the galvanometer mirrors 5 and 6 when the optical axis is scanned in the X direction, and FIG. 2B shows the configuration of the galvanometer mirrors 5 and 6 when the optical axis is scanned in the X direction and the Y direction. It is. For example, in the configuration of the galvanometer mirror shown in FIG. 2A, a two-dimensional image of the cross section of the filter 2 can be obtained by a scanning operation with one optical axis in the X direction.

On the other hand, in the configuration of the galvanometer mirror shown in FIG. 2B, a three-dimensional image of the filter 2 can be obtained by a two-axis scanning operation with the axes in the X direction and the Y direction. Further, the positional deviation of the galvano mirror 6 can be compensated according to the positional deviation of the laser light obtained from the position sensor 15. Next, the position sensor 15 will be described.

The laser beam 300 reflected from the galvanometer mirror 6 enters the detector 4. When the galvanometer mirror is configured as shown in FIG. 2B, the position of the laser beam 300 can be detected in the X and Y directions if the light receiving portion of the position sensor 15 is configured as shown in FIG. Since FIG. 2A is a case where FIG. 2B is limited to the X direction, description thereof is omitted. FIG. 3B shows an optimum state of the laser beam 300 incident on the detector 4, FIG. 3A shows a case where the laser beam 300 is shifted to the + side in the Y direction, and FIG. A case where the direction is shifted to the minus side is shown. FIG. 3E shows an optimum state of the laser beam 300 incident on the detector 4, FIG. 3D shows a case where the laser beam 300 is shifted to the + side in the X direction, and FIG. , Shows a case of shifting to the negative side in the X direction. The position sensor 15 of the detector 4 has four light receiving parts, a light receiving part 301, a light receiving part 302, a light receiving part 303, and a light receiving part 304. In addition, here, signals obtained from the

light receiving units

301, 302, 303, and 304 are A, B, C, and D, respectively. The position error signal Sx in the X direction and the position error signal Sy in the Y direction are obtained by the following equations, for example.
(Expression 1) Sx = (A + B) − (C + D)
(Expression 2) Sy = (A + C) − (B + D)
The calculation of the position error signal is performed by, for example, the position shift signal generation circuit 17, and the rotation drive actuator 13 is driven by, for example, the control unit (B) 14 so that each calculated position error signal becomes zero. It is characterized in that the galvanometer mirror 6 is angularly positioned. In this way, the rotation angle of the rotary drive actuator 13 is detected by the angle detector 12, but the final position stabilization determination is performed directly by the position error signal to directly control the position of the galvanometer mirror. Can do. The reason why stable signal detection is possible is shown below.

In the case of FIG. 3A, the signals of the light receiving unit 302 and the light receiving unit 304 are smaller than the light receiving unit 301 and the light receiving unit 303. For this reason, the signal of Sy becomes positive. On the other hand, in the case of FIG. Therefore, in the case of FIG. 3A, the rotational drive actuator Y of FIG. 2B is controlled to the minus side, and in the case of FIG. It becomes possible to stably control to the state of B).

On the other hand, in the case of FIG. 3D, the signals of the light receiving unit 301 and the light receiving unit 302 are smaller than the light receiving unit 303 and the light receiving unit 304. For this reason, the signal of Sx becomes negative. On the other hand, in the case of FIG. Therefore, in the case of FIG. 3D, the rotational drive actuator X of FIG. 2B is controlled to the plus side, and in the case of FIG. It becomes possible to stably control to the state of E). Next, the detector 4 will be described.

The case where a plurality of resonant tunneling diodes are used for the position sensor 15 of the detector 4 will be described. When detecting incident laser light by a plurality of resonant tunneling diodes having directivity in the polarization direction of the laser light, for example, as shown in FIG. 5A, the resonant tunneling diode 502 adjacent to the resonant tunneling diode 501 By arranging the resonant tunneling diode 503 so that the polarization directions thereof are different by 90 degrees, it is possible to reduce crosstalk noise between adjacent ones. By arranging in this way, it is possible to detect the positional deviation of the laser beam due to the biaxial scanning operation of the galvanometer mirrors 5 and 6 in the X direction and the Y direction.

In the uniaxial scan operation, as shown in FIG. 5B, the region A505 is composed of the resonant tunneling diode 507 and the resonant tunneling diode 508, and the region B506 is composed of the resonant tunneling diode 509 and the resonant tunneling diode 510. A configuration is adopted in which laser beams having polarizations different from each other by 90 degrees in regions A and B are detected.

Here, the configuration of the galvanometer mirror is shown in FIG. 2B. However, if the configuration of the position sensor 15 is as shown in FIG. As described above, the positional deviation of the laser beam 400 can be detected.

In this embodiment, the optical axis scanning is realized by a galvanometer mirror, but the optical axis scanning may be realized by using a polygon mirror or a MEMS (Micro Electro Mechanical Systems) mirror. In addition, although the light receiving portion of the detector 4 is realized by a resonant tunnel diode, a tannet diode, an impatt diode, a Schottky barrier diode, a GaAs field effect transistor, a GaN FET, a high electron mobility transistor, a heterojunction bipolar transistor It may be realized with. Further, here, the control is performed based on the signal of the detector 4, but the positional deviation amount may be learned in advance and the control may be performed based on the learning result.

Furthermore, although the present embodiment shows an example of the configuration of a filter PM collection distribution measuring device, application to a sheet-like medium such as paper can also be applied with the same configuration. The laser light emitted from the oscillating unit 3 is a laser beam having S-polarized light and P-polarized light at a constant light quantity ratio by the polarizing element, but the polarizing element may be integrated with the oscillating unit 3.

FIG. 6 shows the configuration of a PM collection and distribution measuring apparatus for a filter according to a second embodiment of the present invention. The difference between the present embodiment and the first embodiment is the laser beam misalignment signal detection method related to the position sensor 20, the detector 21, and the branching element 22. The rest of the present embodiment is the same as the first embodiment. Now, a signal detection method that is a difference from the first embodiment will be described. In the following, description will be made assuming that the galvano mirror of FIG. 2A is a case where FIG. 2B is limited to the X direction, the description is omitted. Further, laser light emitted from the following oscillating unit 3 is converted into laser light having S-polarized light and P-polarized light at a constant light quantity ratio by a polarizing element.

The laser light reflected from the galvanometer mirror 6 is branched into a main laser beam and a sub laser beam by a branch element 22 such as a diffraction element, and enters a detector 21. FIG. 7 shows the relationship between the light receiving portion of the detector 21 and the main and sub laser beams. Here, FIGS. 7B and 7E show the optimum state of the laser beam incident on the detector 21, and FIG. 7A shows the case where the laser beam is shifted to the + side in the Y direction. (C) shows the case of shifting to the Y direction minus side. The detector 21 includes three light receiving units, a main light receiving unit 701, a sub detection unit 702, a sub detection unit 703, a sub detection unit 704, and a sub detection unit 705.

On the other hand, FIG. 7D shows a case of shifting to the + side in the X direction, and (F) shows a case of shifting to the − side of the X direction. The detector 21 includes three light receiving units, a main light receiving unit 701, a sub detection unit 702, a sub detection unit 703, a sub detection unit 704, and a sub detection unit 705. Further, the interval between the sub detection unit 702 and the sub detection unit 704 is larger than the interval between the sub laser beam 771 and the sub laser beam 772. Similarly, the interval between the sub detection unit 703 and the sub detection unit 705 is also increased.

Here, the galvanometer mirror 6 is controlled using a differential signal of the sum signal of the sub detection unit 702 and the sub detection unit 703 and the sum signal of the sub detection unit 704 and the sub detection unit 705. . The reason why stable signal detection is possible is shown below.

In the case of FIG. 7A, since the sub laser light 771 matches the sub detector 702 and the sub detector 703, the sum signal of the sub detector 702 and the sub detector 703 is sub-detected. The signal is larger than the sum signal of the unit 704 and the sub-detection unit 705. For this reason, the differential signal becomes positive. On the other hand, in the case of FIG. Therefore, in the case of (A), the Y-direction mirror in FIG. 2B is controlled to the minus side, and in the case of (C), the Y-direction mirror is controlled to the plus side. It becomes possible to stably control the state.

On the other hand, in the case of FIG. 7D, since the sub-detector 702 and the sub-detector 704 detect the sub-laser light 771 and the sub-laser light 772, the sub-detector 702 and the sub-detector 704 The sum signal is a larger signal than the sum signal of the sub detection unit 703 and the sub detection unit 705. For this reason, the differential signal becomes positive. On the other hand, in the case of FIG. For this reason, in the case of (D), the X-direction mirror in FIG. 2B is controlled to the minus side, and in the case of (F), the X-direction mirror is controlled to the plus side. It becomes possible to stably control the state. Next, the detector 20 will be described.

The case where the detector 20 uses a plurality of resonant tunneling diodes as an element for detecting the laser light reflected from the galvanometer mirror 6 will be described. When detecting incident laser light by a plurality of resonant tunneling diodes having directivity in the polarization direction of the laser light, for example, a region A505 is configured by a resonant tunneling diode 507 and a resonant tunneling diode 508 as shown in FIG. Then, the region B506 is constituted by the resonant tunneling diode 509 and the resonant tunneling diode 510, and the laser beams having polarization different by 90 degrees in the regions A and B are detected. Here, the case where the galvano mirror has the configuration shown in FIG. 2B is shown, but the configuration shown in FIG. 2A may be the same as that shown in FIG.

In this embodiment, the optical axis scanning is realized by a galvanometer mirror, but the optical axis scanning may be realized by using a polygon mirror or a MEMS mirror. Further, although the position sensor 20 of the detector 21 is realized by a resonant tunnel diode, a tannet diode, an impat diode, a Schottky barrier diode, a GaAs field effect transistor, a GaN FET, a high electron mobility transistor, a heterojunction bipolar You may implement | achieve with a transistor. Further, here, the control is performed based on the signal obtained from the position sensor 20, but for example, the positional deviation amount may be learned in advance and the control may be performed based on the learning result.
Furthermore, although the present Example showed the structural example of PM collection distribution measuring device of a filter, the application to sheet-like media, such as paper, can also be applied with the same structure. The laser light emitted from the oscillating unit 3 is a laser beam having S-polarized light and P-polarized light at a constant light quantity ratio by the polarizing element, but the polarizing element may be integrated with the oscillating unit 3.

FIG. 8 shows the configuration of a filter PM collection and distribution measuring apparatus according to a third embodiment of the present invention. The difference between the present embodiment and the first and second embodiments is that the PM collection distribution measuring apparatus of the present embodiment cancels the influence of moisture absorption and obtains a distribution as a three-dimensional image of the PM concentration deposited on the filter 2. The three-dimensional distribution measurement can be performed by changing the scanning range of the galvanometer mirror from the point that can be measured and the PM concentration. Since other than that is the same as that of Example 1 and 2, in a present Example, the difference with Example 1 is demonstrated. The laser light emitted from the following oscillating unit 30 is converted into laser light having S-polarized light and P-polarized light at a constant light quantity ratio by a polarizing element.

In this embodiment, the first oscillating unit 31 and the detector 4 disposed in the exhaust gas filter 2, the second oscillating unit 32, the detector 33, and the controller 23 disposed on the exhaust downstream side of the filter 2. It consists of. Here, the frequency of the laser light emitted from the first oscillating unit 31 is, for example, a frequency that passes through the non-hydrogen bonding substance and is easily absorbed by the carbon component and the organic solvent component of the exhaust gas particulate component, for example, 0. Uses a terahertz band from 3 THz to 3.0 THz.

The second oscillating unit 32 and the detector 33 are arranged at positions facing the pipe so that the laser beam emitted from the oscillating unit 32 can be received by the photodetector 33. The terahertz wave has a property of transmitting to some extent to semiconductors, ceramics, paper, etc., absorbing to water, and reflecting to metal. For the piping, a material is selected so that the laser beam emitted from the oscillating portion is transmitted to some extent, or only the portions of the oscillating portion and the photodetector are made to transmit the laser beam to some extent.

In addition, in order to measure the light quantity of each laser beam in the filter 2 and downstream, it is set as the structure which divides | segments the laser beam with the polarized light radiate | emitted from the oscillation part 30, for example by the branch elements 80, such as a beam splitter. The arithmetic circuit 81 calculates the ratio between the detector 4 and the detector 33.

The amount of laser light emitted from the first oscillating unit 30 is I ₀ , the absorption rate of the laser beam by α is α, the absorption rate by moisture is β, the absorption rate by PM is γ, and the light received by the detector 4 through the piping When the amount to _{I 1,} for receiving _{I 1} piping, water, the effect of absorption of the PM,
(Equation 3) I ₁ = αβγI ₀
It becomes. On the other hand, if the amount of light emitted from the second oscillating unit 32 is I ₀ as in the first oscillating unit 31, and the amount of light received by the detector 32 through the pipe on the exhaust downstream side of the filter is I ₂ , I ₂ is Although it is affected by piping and moisture absorption, PM is almost removed and has no effect.
(Equation 4) I ₂ = αβI ₀
It becomes. Therefore, by measuring both and taking the ratio, the absorption rate by PM can be obtained as in the following equation.
(Equation 5) I ₁ / I ₂ = γ
Since the PM absorption rate is proportional to the PM concentration, the PM concentration can be calculated from the calculated γ. The controller 23 controls the oscillation unit and the detector. Further, when the PM concentration of the calculation result of the calculation circuit 81 exceeds, for example, 60% or more of the PM amount that can be deposited on the filter, the controller 23 generates an XY coordinate profile that limits the range for measuring the distribution, The profile is sent to the synchronization control unit 16.

According to this embodiment, it is possible to cancel the influence of moisture absorption and obtain a distribution as a three-dimensional image of the PM concentration deposited in the exhaust gas filter 2 with high accuracy in real time. In addition, by supporting the XY coordinates from the controller 23 to the synchronization control unit 16, it is also possible to acquire a local three-dimensional image distribution of PM concentration.

Next, FIG. 9 shows a calculation flow of this embodiment. First, the laser beam emitted from the oscillating unit 30 by the controller 23 is divided into two by the branch element 80, and light is emitted from the first oscillating unit 31 and the second oscillating unit 32 with the light quantity I ₀ . 32, the received light amounts I ₁ and I ₂ are measured (90). Next, the PM absorption rate γ is calculated from the equation (5) by calculating the ratio between I ₁ and I ₂ (91). Next, the PM concentration is calculated from the relationship between the PM concentration and the PM absorption rate (92). Next, if the three-dimensional measurement of the filter 2 is not completed (93), the XY coordinates are sequentially changed by the galvanometer mirror 5 and the galvanometer mirror 6 to perform the three-dimensional measurement of the filter 2 (94).

On the other hand, if the three-dimensional measurement of the filter 2 is completed (94), the PM concentration obtained in the process (92) and a predetermined threshold value, for example, the PM concentration accumulated in the filter 2 are stored in the filter 2. Compare to the accumulable concentration of 60% (95). If the result of this comparison is greater than or equal to the threshold value, the measurement position is limited and the next three-dimensional distribution measurement is executed (97). Further, as a result of the comparison with the threshold value in the process (95), if there is no place exceeding the threshold value, the entire three-dimensional distribution of the filter 2 is measured (96).

Furthermore, although the present embodiment shows an example of the configuration of a filter PM collection distribution measuring device, application to a sheet-like medium such as paper can also be applied with the same configuration. The laser light emitted from the oscillating unit 30 is a laser beam having S-polarized light and P-polarized light at a constant light quantity ratio by the polarizing element, but the polarizing element may be integrated with the oscillating unit 3.

FIG. 10 illustrates the configuration of a water distribution measuring apparatus included in a sheet-like sample, for example, paper 100 used in an image forming apparatus such as a printer, according to this embodiment. The present embodiment is different from the first embodiment in that the frequency of the electromagnetic wave emitted by the oscillating unit 3 is, for example, a frequency that passes through a non-hydrogen bonding substance and is easily absorbed by moisture, for example, 0.1 THz to 3. A terahertz wave band of 0 THz is used. The terahertz wave has a property of transmitting to some extent to semiconductors, ceramics, paper, etc., absorbing to water, and reflecting to metal.

FIG. 10 shows the configuration of the water distribution measuring apparatus for paper 100 according to the fourth embodiment of the present invention. The difference between the present embodiment and the first embodiment is that the measurement system of the present embodiment is an oscillation unit 3, a galvanometer mirror 5, a scanner lens 7, a scanner lens 8, a galvanometer mirror 106, and a detector 4. The feature of this embodiment is that three-dimensional imaging of a sheet-like sample can be performed. Further, as described in the present embodiment, since the position of the galvano mirror can be directly detected by detecting the positional deviation of the laser beam by the detector 4, the galvano mirror 106 does not have an angle detector. Is the feature.

In this embodiment, the laser light emitted from the oscillation unit 3 is reflected by the galvanometer mirror 5 and enters the paper 100. The laser light transmitted through the paper is incident on the detector 4 through the scanner lens 7, the scanner lens 8, and the galvanometer mirror 106. Here, the galvanometer mirror 5 can rotate around the rotation axis of the rotary drive actuator 10 to change the angle. The rotation angle of the rotary drive actuator 10 is detected by the angle detector 9, and the detected signal is input to the arithmetic circuit (A) 18.

The arithmetic circuit (A) 18 generates a drive signal necessary for the galvano mirror 5 to perform positioning control at a predetermined angle. Based on this control signal, the control unit (A) 11 sends a drive control signal to the rotary drive actuator 10. Is sent out. For example, the arithmetic circuit (A) 18 generates a drive signal for reciprocating the galvanometer mirror 105 within a predetermined angle range, for example, 30 deg, and the control unit (A) 11 controls the rotary drive actuator 10, so that the laser The light can be scanned, and the paper 100 can pass uniformly. At this time, since the absorption rate of water contained in the paper can be detected by detecting the signal of the detector 4, for example, while observing a change in water when shaping an image on paper with a printer or the like. Ink can be controlled.

Furthermore, in this embodiment, the laser beam that has passed through the paper 100 is incident on the detector 4 via the scanner lens 8 and the galvanometer mirror 106. However, in a detector using a semiconductor element, misalignment or the like becomes a problem. For this reason, for example, the amount of light reduction may be learned in accordance with the incident angle to the semiconductor element and corrected using the learned amount. This correction optical control means will be described below. In order to correct the misalignment at the detector 4, the galvanometer mirror 106 can rotate around the rotation axis of the rotary drive actuator 13 to change the angle. A signal for detecting the optical axis deviation angle is provided by the position sensor 15 provided in the detector 4 for optical axis positional deviation correction, and the optical axis positional deviation compensation signal generated by the positional deviation signal generation circuit 17 is provided. And the position profile of the galvanometer mirror 106 sent from the synchronization control unit 16 are input to the arithmetic circuit (B) 19. The arithmetic circuit (B) 19 generates a drive signal necessary for controlling the galvanometer mirror 106 to a predetermined position by the rotational position control, and the control unit (B) 14 based on the control signal causes the rotational drive actuator 13 to operate. A drive control signal is sent to. With such correction optical control means, the optical axis can be controlled to a predetermined position of the detector 4 by performing an optical axis position correction operation.

Here, the galvano mirror 106 needs to be driven in synchronism with the galvano mirror 5. Therefore, the synchronization control unit 16 sends the position profile of the galvano mirror 5 to the arithmetic circuit (A) 18 and receives the position information of the galvano mirror 105 from the angle detector 9 through the arithmetic circuit (A) 18. 16 sends the position profile of the galvanometer mirror 106 to the arithmetic circuit (B) 19, and the galvanometer mirrors 5 and 106 realize a synchronized scanning operation. Here, for example, the misalignment signal generation circuit 17 synchronizes the galvano mirror 106 by sending a signal indicating that the galvano mirror 106 is controlled within a predetermined angle range, for example, a static angle width within ± 1 mdeg, to the synchronization control unit 16. Realize control. Next, the galvanometer mirror 106 will be described. The configuration of the galvanometer mirror 5 is the same as that of FIG. 2 described in the first embodiment.

11A shows the configuration of the galvanometer mirror 106 when the optical axis is scanned in the X direction, and FIG. 11B shows the configuration of the galvanometer mirror 106 when the optical axis is scanned in the X direction and the Y direction. The difference between FIG. 2 and FIG. 11 is the presence or absence of an angle detector. In FIG. 11, the detector 4 functions as the function of the angle detector. For example, in the configuration of the galvanometer mirror in FIGS. 2A and 11A, a two-dimensional image of the cross section of the filter 2 can be obtained by a single-axis scanning operation in the X direction. On the other hand, in the configuration of the galvanometer mirror shown in FIGS. 2B and 11A, a three-dimensional image of the paper 100 can be obtained by a two-axis scanning operation with the axes in the X direction and the Y direction. Further, the positional deviation of the galvano mirror 106 can be compensated according to the positional deviation of the laser light obtained from the position sensor 15. Next, the position sensor 15 will be described.

The laser beam 300 reflected from the galvanometer mirror 106 is incident on the detector 4. When the galvanometer mirror is configured as shown in FIG. 11B, the position of the laser beam 300 can be detected in the X and Y directions if the light receiving portion of the position sensor 15 is configured as shown in FIG. FIG. 11A illustrates a case where FIG. 11B is limited to the X direction, and thus description thereof is omitted. The position error signal Sx in the X direction and the position error signal Sy in the Y direction are obtained by (Equation 1) and (Equation 2) as in the first embodiment.

The calculation of the position error signal is performed by, for example, the position shift signal generation circuit 17, and the rotation drive actuator 13 is driven by, for example, the control unit (B) 14 so that each calculated position error signal becomes zero. The galvano mirror 106 is positioned at an angle. By doing so, the position stabilization determination of the rotation angle of the rotary drive actuator 13 is performed by the position error signal, and the position of the galvano mirror is directly controlled. The reason why stable signal detection is possible is shown below.

In the case of FIG. 3A, the signals of the light receiving unit 302 and the light receiving unit 304 are smaller than the light receiving unit 301 and the light receiving unit 303. For this reason, the signal of Sy becomes positive. On the other hand, in the case of FIG. Therefore, in the case of FIG. 3A, the rotational drive actuator Y of FIG. 11B is controlled to the minus side, and in the case of FIG. It becomes possible to stably control to the state of B).

On the other hand, in the case of FIG. 3D, the signals of the light receiving unit 301 and the light receiving unit 302 are smaller than the light receiving unit 303 and the light receiving unit 304. For this reason, the signal of Sx becomes negative. On the other hand, in the case of FIG. Therefore, in the case of FIG. 3D, the rotational drive actuator X of FIG. 11B is controlled to the plus side, and in the case of FIG. It becomes possible to stably control to the state of E).

In the present embodiment, the configuration in which only the galvanometer mirror 106 has no angle detector has been described. Here, since the positional deviation signal detected by the detector 4 detects the relative angular deviation between the galvano mirror 106 and the galvano mirror 5 as a positional deviation, for example, the angular detector of the galvano mirror 5 is eliminated and the positional deviation signal is detected. Thus, it is possible to compensate for the relative displacement between the galvanometer mirror 5 and the galvanometer mirror 106, and the galvanometer mirror 5 may not have an angle detector. The configuration at that time is the same as that shown in FIG.

In this embodiment, the optical axis scanning is realized by a galvanometer mirror, but the optical axis scanning may be realized by using a polygon mirror or a MEMS mirror. In addition, although the light receiving portion of the detector 4 is realized by a resonant tunnel diode, a tannet diode, an impatt diode, a Schottky barrier diode, a GaAs field effect transistor, a GaN FET, a high electron mobility transistor, a heterojunction bipolar transistor It may be realized with. Further, here, the control is performed based on the signal of the detector 4, but the positional deviation amount may be learned in advance and the control may be performed based on the learning result.

Furthermore, although this embodiment is applied to application to a sheet-like medium such as paper, it is not limited to this. The laser light emitted from the oscillating unit 3 is a laser beam having S-polarized light and P-polarized light at a constant light quantity ratio by the polarizing element, but the polarizing element may be integrated with the oscillating unit 3.

The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment. For example, there are the following examples.

As a first modification, a first oscillation unit that generates a first laser beam, a first detection unit that detects the first laser beam, a first lens and a second lens that are arranged to face each other A first optical axis scanning unit that scans an optical axis of the first laser beam positioned between the lens, the first oscillation unit, and the first lens, the second lens, and the first lens A second optical axis scanning unit that scans the optical axis of the first laser beam located between the first detector, a first control unit that controls the first optical axis scanning unit, and A second control unit that controls the second optical axis scanning unit, a first control unit, and a scanning instruction unit that provides control information to the second control unit, wherein the first detection unit includes: The first laser beam is detected through the first optical axis scanning unit, the first lens, the second lens, and the second optical axis scanning unit, and the second optical axis scanning unit Control unit, said scanning from said instruction unit first is controlled based on a detection signal of the control information and the first detection portion in the optical axis control unit, the laser beam position controller.

As a second modification, the laser beam position control device according to the first modification, wherein the first detection unit detects a positional deviation of the first laser beam with a plurality of sensors, and the first detection unit. And an arithmetic circuit for calculating a position shift signal of the laser beam by calculating each of the signals output from the first control unit, wherein the first control unit includes the position shift signal generated by the arithmetic circuit. A laser beam position control device controlled by

Modification 3 is the laser beam position control apparatus according to Modification 2, in which the first oscillation unit that generates the first laser beam, the polarization variable element that adjusts the polarization of the laser beam, and 2 The first detection unit having a plurality of sensor units composed of one or more sensors and a sensor unit composed of at least one sensor, and each of the signals output from the plurality of sensor units is calculated, and the laser An arithmetic circuit that generates a positional deviation signal of the light, wherein the sensors adjacent to each other of the plurality of sensors are arranged so that the light receiving polarization angles of the first laser beams are different from each other, and are output from the plurality of sensors. A laser beam position control device in which the second optical axis scanning unit is controlled based on a position shift signal generated from the signal by the arithmetic circuit.

As a fourth modification, an oscillation unit that generates laser light, a polarization variable element that adjusts polarization of the laser light, a detection unit that detects the laser light with two or more sensors, and an optical axis of the laser light An optical axis scanning unit that scans, and a control unit that controls the optical axis scanning unit, wherein the sensors adjacent to each other of the plurality of sensors are arranged such that the light receiving polarization angles of the laser beams are different from each other, The laser beam position control device, wherein the optical axis control unit is controlled based on each output signal.

As a modified example 5, the laser beam position control device according to the modified example 2, wherein the second oscillation unit that generates the second laser beam, the second detection unit that detects the second laser beam, The first detection unit is a ratio of a signal obtained by detecting the first laser beam by the first detection unit and a signal obtained by detecting the second laser beam by the second detection unit. And a calculation unit for obtaining the signal intensity of the first and second components, and a range in which the optical axis is scanned by the first control unit and the second control unit is changed based on the signal intensity of the calculation unit. Laser beam position scanning device.

As a sixth modification, the laser beam position scanning device according to the fifth modification includes a branch element that branches the first laser light, and the first laser light branched by the branch element is used. A laser beam position that is used as the second oscillating unit, and that changes a range in which the optical axis is scanned by the first control unit and the second control unit based on the signal intensity of the arithmetic unit. Scanning device.

In addition, each of the above-described configurations, functions, processing units, processing means, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor. Information such as programs, tables, and files for realizing each function can be stored in a recording device such as a memory, a hard disk, or an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

DESCRIPTION OF SYMBOLS 1 ... Engine waste pipe 2 ... Filter 3 ... Oscillation part,
4 ... Detector,
5 ... Galvano mirror,
6 ... Galvano mirror,
7 ... Scanner lens,
8 ... Scanner lens,
9: Angle detector,
10: Rotation drive actuator,
12 ... An angle detector,
13 ... Rotation drive actuator,
15 ... Position sensor,
22 ... Branch element 23 ... Controller,

Claims

A first oscillation unit for generating a first laser beam;
A first detector for detecting the first laser beam;
A first lens and a second lens arranged opposite to each other;
A first optical axis scanning unit that scans an optical axis of the first laser beam located between the first oscillation unit and the first lens;
A second optical axis scanning unit that scans an optical axis of the first laser beam located between the second lens and the first detector;
A first control unit for controlling the first optical axis scanning unit;
A second control unit for controlling the second optical axis scanning unit;
A scanning instruction unit that gives control information to the first control unit and the second control unit,
The first detection unit detects the first laser beam via the first optical axis scanning unit, the first lens, the second lens, and the second optical axis scanning unit,
The second control unit controls the second optical axis scanning unit based on the control information from the scanning instruction unit to the first optical axis scanning unit and a detection signal of the first detection unit. A laser beam position control device.
The laser beam position control device according to claim 1,
A calculation circuit that calculates a signal output from the first detection unit and generates a positional deviation signal of the laser beam, and
The first detection unit includes a plurality of sensors that detect a positional shift of the first laser beam,
The arithmetic circuit calculates each signal detected by the plurality of sensors to generate the positional deviation signal,
The laser beam position control device, wherein the first control unit controls the first optical axis scanning unit based on a positional shift signal generated by the arithmetic circuit.
The laser beam position control device according to claim 2,
A polarization variable element for adjusting the polarization of the laser light;
With
The first detection unit has a plurality of sensor units composed of two or more sensors and a sensor unit composed of one sensor,
The sensors adjacent to each other of the plurality of sensor units are arranged such that the light receiving polarization angles of the first laser light incident via the polarization variable element are different from each other,
The second control unit controls the second optical axis scanning unit based on the positional deviation signal generated by calculating each signal detected by the plurality of sensor units by the arithmetic circuit. Position control device.
The laser beam position control device according to claim 2,
A second oscillation unit for generating a second laser beam;
A second detector for detecting the second laser beam;
The arithmetic circuit has a ratio of a signal obtained by detecting the first laser beam by the first detector and a signal obtained by detecting the second laser beam by the second detector. Determining the signal strength of the first detector;
The first control unit and the second control unit are configured to scan the optical axis by the first optical axis scanning unit and the second optical axis scanning unit based on the signal intensity obtained by the arithmetic circuit. The laser beam position control device characterized by changing the above.
The laser beam position control device according to claim 2,
A branch element for branching the first laser beam to generate a second laser beam;
A second detector for detecting the second laser beam;
With
The arithmetic circuit has a ratio of a signal obtained by detecting the first laser beam by the first detector and a signal obtained by detecting the second laser beam by the second detector. Determining the signal strength of the first detector;
The first control unit and the second control unit are configured to scan the optical axis by the first optical axis scanning unit and the second optical axis scanning unit based on the signal intensity obtained by the arithmetic circuit. The laser beam position control device characterized by changing the above.
An oscillation unit for generating laser light;
A polarization variable element for adjusting the polarization of the laser light;
A detection unit for detecting the laser beam with two or more plural sensors;
An optical axis scanning unit that scans the optical axis of the laser beam;
A control unit for controlling the optical axis scanning unit,
The sensors adjacent to each other of the plurality of sensors are arranged so that the light receiving polarization angles of the laser light incident via the polarization variable element are different from each other,
The said control part controls the said optical axis control part based on each signal output from the said several sensor, The laser beam position control apparatus characterized by the above-mentioned.
A measuring device that performs measurement by irradiating an object to be inspected with laser light,
A first oscillation unit for generating a first laser beam;
A first detector for detecting the first laser beam;
A first lens and a second lens arranged opposite to each other;
A first optical axis scanning unit that scans an optical axis of the first laser beam located between the first oscillation unit and the first lens;
A second optical axis scanning unit that scans an optical axis of the first laser beam located between the second lens and the first detector;
A first control unit for controlling the first optical axis scanning unit;
A second control unit for controlling the second optical axis scanning unit;
A scanning instruction unit that gives control information to the first control unit and the second control unit,
The first detection unit detects the first laser beam via the first optical axis scanning unit, the first lens, the second lens, and the second optical axis scanning unit,
The second control unit controls the second optical axis scanning unit based on the control information from the scanning instruction unit to the first optical axis scanning unit and a detection signal of the first detection unit. To
A measuring device that performs measurements.
It is a measuring device of Claim 7, Comprising:
A calculation circuit that calculates a signal output from the first detection unit and generates a positional deviation signal of the laser beam, and
The first detection unit includes a plurality of sensors that detect a positional shift of the first laser beam,
The arithmetic circuit calculates each signal detected by the plurality of sensors to generate the positional deviation signal,
The first control unit is a measurement device that performs measurement by controlling the first optical axis scanning unit based on a positional deviation signal generated by the arithmetic circuit.
It is a measuring device of Claim 8, Comprising:
A polarization variable element for adjusting the polarization of the laser light;
With
The first detection unit has a plurality of sensor units composed of two or more sensors and a sensor unit composed of one sensor,
The sensors adjacent to each other of the plurality of sensor units are arranged such that the light receiving polarization angles of the first laser light incident via the polarization variable element are different from each other,
The second control unit controls the second optical axis scanning unit based on the positional deviation signal generated by calculating each signal detected by the plurality of sensor units by the arithmetic circuit. A measuring device that performs measurements.
It is a measuring device of Claim 8, Comprising:
A second oscillation unit for generating a second laser beam;
A second detector for detecting the second laser beam;
The arithmetic circuit has a ratio of a signal obtained by detecting the first laser beam by the first detector and a signal obtained by detecting the second laser beam by the second detector. Determining the signal strength of the first detector;
The first control unit and the second control unit are configured to scan the optical axis by the first optical axis scanning unit and the second optical axis scanning unit based on the signal intensity obtained by the arithmetic circuit. A measuring device that performs measurement by changing.
It is a measuring device of Claim 8, Comprising:
A branch element for branching the first laser beam to generate a second laser beam;
A second detector for detecting the second laser beam;
With
The arithmetic circuit has a ratio of a signal obtained by detecting the first laser beam by the first detector and a signal obtained by detecting the second laser beam by the second detector. Determining the signal strength of the first detector;
The first control unit and the second control unit are configured to scan the optical axis by the first optical axis scanning unit and the second optical axis scanning unit based on the signal intensity obtained by the arithmetic circuit. A measuring device that performs measurement by changing.
An oscillation unit for generating laser light;
A polarization variable element for adjusting the polarization of the laser light;
A detection unit for detecting the laser beam with two or more plural sensors;
An optical axis scanning unit that scans the optical axis of the laser beam;
A control unit for controlling the optical axis scanning unit,
The sensors adjacent to each other of the plurality of sensors are arranged so that the light receiving polarization angles of the laser light incident via the polarization variable element are different from each other,
The said control part controls the said optical axis control part based on each signal output from the said several sensor, The measuring device which measures by this is characterized by the above-mentioned.
The laser beam position control device according to claim 2,
The first and second optical axis scanning units are galvanometer mirrors,
The first and second control units are rotational drive actuators that drive the optical axis scanning unit,
The rotation drive actuator is a laser beam position control device, wherein the first detection unit drives the galvanometer mirror based on a detection signal.