JP3785457B2 - Optical fiber sensor and stress measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention does not require a special power supply device for driving the sensor, and is not affected by electromagnetic noise, and uses an optical fiber sensor that can be used for remotely measuring pressure, and the optical fiber sensor. The present invention relates to a stress measuring apparatus.
[0002]
[Prior art]
Conventionally, as a pressure sensor, a thin elastic plate is used as a diaphragm, and a sensor that converts the deformation due to pressure into an electric signal by a strain gauge or a piezoresistive element attached to the diaphragm is often used.
[0003]
However, since such a pressure sensor uses an electrical signal, it is susceptible to electromagnetic noise and cannot be used in a flammable environment.
[0004]
At this time, when an optical fiber is employed for the signal transmission system of the pressure sensor, electromagnetic noise resistance can be imparted. Nevertheless, since the power supply to the sensor element itself is necessary, the problem of flammability cannot be solved.
[0005]
Therefore, in order to solve the above problems, a diaphragm having a mirror surface on one side is attached to the tip of the optical fiber, and the laser beam passing through the optical fiber is reflected on the diaphragm so that the deformation of the diaphragm becomes an interference between incident light and reflected light. An optical fiber sensor that converts pressure and measures pressure has been proposed (see T. Katsumata, et al .: T. IEE Japan, 120-E, No. 2, 58-63 (2000)). There has also been proposed an optical fiber sensor that detects a pressure from a Brillouin gain spectrum observed when a pulsed laser beam is incident on an optical fiber and the optical fiber is subjected to pressure (see http://www.ntt). .co.jp / news / news97 / 970529a.html).
[0006]
[Problems to be solved by the invention]
However, the conventional optical fiber sensor as described above has a problem that pressure cannot be measured unless laser light is always incident on the optical fiber. That is, in the conventional optical fiber sensor, since it is necessary to always inject laser light, for example, there is a limit in downsizing, and there is a problem in cost.
[0007]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical fiber sensor capable of measuring stress remotely without requiring laser light irradiation, and stress measurement using the optical fiber sensor. To provide an apparatus.
[0008]
[Means for Solving the Problems]
As will be described later, the present inventors applied various loads to a bulk body prepared by mixing a stress-stimulated luminescent material that emits light due to stress and a transparent optical resin. It has been found that the emission intensity is high and the emission intensity increases in proportion to the stress. Furthermore, when this light is measured by a photodetector or the like through an optical path such as glass fiber, it has been uniquely found that the stress generated in the bulk body can be remotely measured, and the present invention has been completed based on these findings. It was.
[0009]
That is, in order to solve the above-described problems, the optical fiber sensor according to the present invention is provided with a light-emitting portion having a stress-stimulated luminescent material whose light emission intensity increases in proportion to the magnitude of stress at the end of the optical fiber. And a reflection part for reflecting the light emitted from the light emitting part is formed on the surface of the light emitting part other than the coupling part between the light emitting part and the optical fiber. The light emitting portion has a three-dimensional shape, and the light emitting portion is formed so as to be in contact with the end face of the core layer of the optical fiber and not in contact with the end face of the cladding layer. It is characterized by being.
[0010]
According to the above configuration, when a load is applied from the outside to the light emitting portion provided at the end portion (including the end face) of the optical fiber and stress is generated therein, the stress light emitting material in the light emitting portion has a large stress. It emits light with an emission intensity proportional to the depth. This light is transmitted directly or after being reflected by the reflecting portion, via an optical fiber. For example, this light is detected by a photodetector provided at the other end of the optical fiber.
[0011]
The optical fiber sensor can be used, for example, when measuring a stress at a measurement point.
[0012]
Further, since the light emitting part of the optical fiber sensor has a reflection part on the surface, the light emitted by the stress generated by applying a load to the light emitting part is reliably leaked without leaking to the outside. Can be used to accurately measure stress.
[0013]
Therefore, the above optical fiber sensor does not require a special power supply device to drive the sensor, and is not affected by electromagnetic noise. Can be used for telemetry. For this reason, it is possible to reduce the size of the optical fiber sensor and to reduce the cost.
[0014]
Furthermore, in the optical fiber sensor, the shape of the surface of the light emitting part other than the coupling part between the light emitting part and the optical fiber may be parabolic.
[0015]
According to said structure, the light which generate | occur | produces with the stress which arises when a load is applied to the light emission part can be more efficiently sent out via an optical fiber. In addition, although the shape of the surface of the coupling | bond part of the said light emission part and the said optical fiber is preferable in a plane, it is not specifically limited, Arbitrary shapes, such as paraboloid shape, may be sufficient.
[0016]
Therefore, for example, when a photodetector or the like is provided at the other end of the optical fiber, the light intensity can be detected more efficiently. For this reason, the said optical fiber sensor can be utilized for stress measurement more efficiently.
[0017]
The light emitting unit may include a stress light emitting material and an optical resin.
[0018]
According to said structure, optical resin can be used as a kind of binder of stress luminescent material. Thereby, it becomes easy to shape | mold a light emission part in the shape which can send out light more efficiently. For example, as described above, a dome-shaped light-emitting portion having a parabolic surface shape can be easily formed.
[0019]
Further, the stress measuring device according to the present invention includes a light detection unit for detecting light emitted from the light emitting unit at an end of the optical fiber of the optical fiber sensor other than the end provided with the light emitting unit. And a stress measuring unit for measuring the magnitude of stress based on the light information detected by the light detecting unit.
[0020]
According to the above configuration, when a load is applied to the light emitting part provided at one end of the optical fiber and stress is generated, the stress light emitting material in the light emitting part emits light having a light emission intensity proportional to the magnitude of the stress. discharge. This light is transmitted through an optical fiber directly or after being reflected by a reflecting portion.
[0021]
This light is detected by a light detection unit provided at the other end of the optical fiber. Next, since the stress of the light emitting unit can be calculated by the stress measuring unit based on the detected light information (for example, emission intensity, emission spectrum, etc.), the applied load can be measured.
[0022]
The stress measuring device can be used, for example, when measuring a stress at a measurement point, and can remotely measure the stress generated in the light emitting unit, that is, the load applied to the light emitting unit.
[0023]
Therefore, the stress measuring device does not require a special power supply device to drive the sensor, and is not affected by electromagnetic noise. Telemetry can be performed. For this reason, it is possible to further reduce the size of the stress measuring device and to reduce the cost.
[0024]
In order to solve the above problems, an optical fiber sensor according to the present invention emits light having a stress-stimulated luminescent material whose light emission intensity increases in proportion to the stress along the central axis of the optical fiber. Layer is provided The light emitting layer is provided at the center of the optical fiber. It is characterized by being.
[0025]
According to the above configuration, when a load is applied to the light emitting layer provided along the central axis of the optical fiber to generate a stress, the stress light emitting material in the light emitting layer emits light having an intensity proportional to the strength of the stress. To do. This light is transmitted through an optical fiber. For example, this light is detected by a photodetector or the like provided at the end of the optical fiber.
[0026]
In other words, the optical fiber sensor can be used when measuring stress without determining measurement points, for example, when measuring stress along a straight line or a curve. For this reason, it can utilize when measuring the continuous applied stress (distortion etc.) which is not measurement of a point.
[0027]
In addition, the above optical fiber sensor does not require a special power supply device to drive the sensor, and is not affected by electromagnetic noise. Can be used for telemetry. For this reason, not only can the optical fiber sensor be reduced in size, but also cost reduction can be achieved.
[0028]
The optical fiber sensor may be configured such that a plurality of the light emitting layers are provided in the longitudinal direction of the optical fiber, and each of the light emitting layers has a stress light emitting material having a different emission spectrum. .
[0029]
According to the above configuration, by identifying the characteristics of the emission spectrum of the light emitted from the stress-stimulated luminescent material, stress is generated and light is emitted from a plurality of light emitting layers provided in the longitudinal direction of the optical fiber. The light emitting layer can be specified, and the position where the load is applied in the longitudinal direction of the optical fiber can be specified. Furthermore, the magnitude of the stress applied to each light emitting layer can also be measured by measuring the magnitude of the stress from the light emission intensity.
[0030]
Therefore, even if a load is applied simultaneously at a plurality of positions of the optical fiber sensor, the load and the magnitude of the load in which region of the optical fiber of the optical fiber sensor is determined from the characteristics and emission intensity of each detected emission spectrum. It can be specified whether it is applied. That is, each detected emission spectrum can be used to specify the position and size at which each load is applied.
[0031]
In addition, the stress measurement device according to the present invention includes a light detection unit for detecting light emitted from the light emitting layer at the end of the optical fiber in the optical fiber sensor. A stress measuring unit for measuring and specifying the magnitude of the applied load and / or the position of the applied load based on the detected light information is provided.
[0032]
According to the above configuration, when a load is applied to the light emitting layer provided along the central axis of the optical fiber of the optical fiber sensor, the stress light emitting material in the light emitting layer is proportional to the strength of the stress generated by the load. Emits light of the emission intensity. This light is transmitted through an optical fiber.
[0033]
And this light is detected by the light detection part provided in the edge part of the optical fiber. Based on the detected light information (for example, light emission intensity, light emission spectrum, wavelength, frequency, etc.), the stress measurement unit can calculate the stress generated in the light emitting layer and measure the applied load. be able to.
[0034]
In addition, when the optical fiber sensor includes a plurality of light emitting layers having stress light emitting materials having different emission spectra, information on the light detected by the light detection unit (for example, emission intensity, emission spectrum, wavelength, frequency, etc.) ), The stress measurement unit can specify the position of the load applied to the optical fiber sensor.
[0035]
The stress measuring device according to the present invention can perform both the process of measuring the magnitude of the load applied to the optical fiber sensor and the process of specifying the position where the load is applied, or either one of them. It is also possible to perform only the above process, and there is no particular limitation.
[0036]
In addition, the stress measuring device according to the present invention can be used when measuring stress without determining measurement points, for example, when measuring stress along a straight line or curve, and applying a load to the light emitting layer. The generated stress can be remotely measured.
[0037]
Therefore, even when a plurality of loads are applied to the optical fiber sensor at a plurality of positions at the same time, the stresses generated by them can be separated and the magnitude and position of each stress can be specified.
[0038]
In addition, the stress measuring device does not require a special power supply device to drive the sensor, and is not affected by electromagnetic noise. Telemetry can be performed. For this reason, it is possible to further reduce the size of the stress measuring device and to reduce the cost.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
The present invention does not require a special power supply to drive the sensor, is not affected by electromagnetic noise, and is also used for remote measurement of stress without irradiating laser light. The present invention provides a possible optical fiber sensor and a stress measuring device using the optical fiber sensor. Therefore, hereinafter, an optical fiber sensor according to the present invention will be described, and then an example of a stress measuring apparatus using the optical fiber sensor will be described.
[0040]
[Embodiment 1]
An embodiment of the present invention will be described as follows. Note that the present invention is not limited to this.
[0041]
(1) Optical fiber sensor 1
(1-1) Configuration of the optical fiber sensor 1
FIG. 1 is a cross-sectional view of the vicinity of a light emitting part, which is a characteristic part of an embodiment of an optical fiber sensor according to the present invention, cut along a plane along the axial direction (longitudinal direction) of an optical fiber. As shown in FIG. 1, the optical fiber sensor 1 includes an optical fiber 10, a light emitting unit 3, a reflecting unit 6, and a protective layer 8.
[0042]
The optical fiber 10 has a double structure including a core layer 4 that is a high refractive index region and a cladding layer 5 that is a low refractive index region. The “optical fiber” here is not particularly limited as long as it is an optical path through which light such as glass fiber passes. For the core layer 4 and the clad layer 5, conventionally known materials can be used and are not particularly limited.
[0043]
The light emitting unit 3 is provided at the end (including the end face) 10 a of the optical fiber 10. The light emitting unit 3 is formed on the end face of the optical fiber 10, and it is preferable that the light generated in the light emitting unit 3 can be more reliably sent to the core layer 4 of the optical fiber 10. That is, the light emitting unit 3 is more preferably formed so as to be in contact with the end surface of the core layer 4 of the optical fiber 10 and not in contact with the end surface of the cladding layer 5. Thereby, the light generated in the light emitting unit 3 can be transmitted to the core layer 4 of the optical fiber 10 more reliably.
[0044]
The light emitting unit 3 is described in, for example, Japanese Patent Application Laid-Open No. 11-116946, Japanese Patent Application Laid-Open No. 2001-049251, Japanese Patent Application Laid-Open No. 2001-064638, Japanese Patent No. 3273317, and Japanese Patent No. 2999631. Such a stress-stimulated luminescent material whose luminescence intensity increases in proportion to the magnitude of the stress generated by an externally applied load (for example, strontium carbonate and alumina, ZnS: Mn, ZnS: Cu, spinel structure, MAl ₂ O _Four : N (where M = Mg, Ca, Sr, Ba; N = Eu, Ce, Tb, Sm, Cu, Mn), M _Three Al ₂ O ₆ : N, MAl ₁₂ O ₁₉ : N, melilite structure oxide, Ca ₂ Al ₂ SiO ₇ : N, MMgAl _Ten O ₁₇ : N, M _Three MgSi ₂ O ₈ : N (where M = Ba, Sr, Ca; N = Eu, Ce, Sm, Cu, Mn), etc.), and is not particularly limited. That is, the stress-stimulated luminescent material can be used alone for the light-emitting portion 3, or the stress-stimulated luminescent material and other substances (inorganic substances such as alumina and silica, and organic substances such as plastic, resin, and rubber). Can also be used as a mixture.
[0045]
The stress-stimulated luminescent material used for the optical fiber sensor 1 of the present invention is an oxide-based ceramic made into fine particles. For this reason, for example, when forming (manufacturing) the light emitting part 3 using only the stress luminescent material, it is necessary to form by sintering, and it is difficult to precisely process the once formed. For this reason, when manufacturing the light emission part 3, it is more preferable to use an optical resin as a kind of binder, for example.
[0046]
For this reason, in the present embodiment, the light-emitting portion 3 is formed by mixing the stress-stimulated luminescent material in powder form into a transparent optical resin and molding it into a dome shape. Thereby, the light emission part 3 can be shape | molded more easily.
[0047]
In addition, experiments and results of applying various loads to a bulk body in which the stress-stimulated luminescent material and a transparent optical resin are mixed are described in detail in JP-A-2001-215157. Specifically, as described in FIG. 9 and FIG. 9 of the same publication, a bulk body in which a stress-stimulated luminescent material and a transparent optical resin are mixed is formed into a cylindrical shape, and a compression force (from above and below) When a load was applied, the emission intensity distribution in the cylindrical cross section of the generated light was measured. As a result, the theoretical analysis value of the stress distribution in the cylinder and the emission intensity showed a good correlation. From this, it has been experimentally shown that even when the stress-stimulated luminescent material is mixed with a transparent optical resin or the like, the luminescence intensity increases in proportion to the stress.
[0048]
The mixing ratio of the stress-stimulated luminescent material and the transparent optical resin in the light emitting unit 3 according to the present embodiment is preferably 10 to 90% (weight ratio), and more preferably 70 to 90% (weight). Ratio). If it is the light emission part 3 formed with the said mixing ratio, stress can fully be measured from the generated light.
[0049]
The light emitting unit 3 can have any three-dimensional shape such as a sphere, a hemisphere, a triangular pyramid, a cone, a cube, and a rectangular parallelepiped, but efficiently transmits light generated by applied stress to the optical fiber 10. In order to do so, the surface shape is preferably a parabolic shape.
[0050]
Moreover, the method of forming the light emission part 3 can use a conventionally well-known method, and is not specifically limited. Specifically, a mixture of the stress-stimulated luminescent material and the optical resin is poured into a mold (dome-shaped mold) of the light emitting section 3 to which the optical fiber 10 is fixed in advance, and is cured by heat treatment or the like. The method of doing is mentioned. At this time, the affinity between the optical fiber 10 and the optical resin is important. Therefore, it is preferable to use polyimide, polyethylene terephthalate, polycarbonate, transparent silicon rubber, or the like as the optical resin to be used.
[0051]
Further, for example, it is possible to attach the light emitting unit 3 to the end 10 a of the optical fiber 10 using a transparent resin as an adhesive.
[0052]
The reflection unit 6 is provided on the surface of the light emitting unit 3 other than the coupling unit 3 a between the light emitting unit 3 and the optical fiber 10. The reflection unit 6 is not particularly limited as long as it is an optical reflection film for preventing light emitted from the light emitting unit 3 from leaking outside the optical fiber sensor 1. Specifically, it is preferable to use, for example, a metal film such as aluminum, gold, platinum, nickel, and titanium for the reflecting portion 6. Moreover, the formation method of the reflection part 6 can utilize a conventionally well-known method, and is not restricted in particular. Specifically, the reflection part 6 can be formed, for example, by vapor deposition after the light emitting part 3 is formed.
[0053]
The protective layer 8 is not particularly limited as long as it protects the optical fiber sensor 1 physically or chemically. For example, a conventionally known material such as polyvinyl chloride (PVC) can be used.
[0054]
The optical fiber sensor 1 according to the present invention has a light-emitting dome formed from a stress-luminescent material that emits light in proportion to stress in a dome shape, and an optical reflective film is formed on the surface of the light-emitting dome. It can be paraphrased as an attached one.
[0055]
(1-2) Functions of the optical fiber sensor 1
Since the optical fiber sensor 1 has the above structure, it has the following functions.
[0056]
When the stress measurement is performed with the measurement points set, it is preferable to use the optical fiber sensor 1 described above. That is, when a load is applied from the outside to the light emitting unit 3 provided at the end 10 a of the optical fiber sensor 1, the stress light emitting material in the light emitting unit 3 emits light in proportion to the magnitude of the stress. This light is transmitted to the core layer 4 of the optical fiber 10 directly or after being reflected by the reflecting portion 6.
[0057]
Therefore, for example, if a photodetector or the like is provided at an end different from the end 10a where the light emitting unit 3 of the optical fiber 10 is provided, the magnitude of the stress of the light emitting unit 3 is calculated from the light emission intensity. Thus, the magnitude of the applied load can be calculated.
[0058]
Further, the optical fiber sensor 1 according to the present invention does not require a special power supply device for driving the sensor, and can be used even in a flammable environment. In addition to being not affected by electromagnetic noise, the laser light can be used for remote measurement of stress without being always incident.
[0059]
For this reason, the optical fiber sensor 1 according to the present invention can be used for medical examinations and treatments, for example, by using it for a catheter used for endovascular treatment. It can also be used for disaster relief, inspection and maintenance without entering and disassembling complex machines and piping.
[0060]
[Embodiment 2]
Another embodiment of the optical fiber sensor according to the present invention will be described below with reference to FIG.
[0061]
For convenience of explanation, members having the same functions as those described in the first embodiment are denoted by the same reference numerals and description thereof is omitted. In the present embodiment, differences from the first embodiment will be described.
[0062]
(2) Optical fiber sensor 11
(2-1) Configuration of the optical fiber sensor 11
FIG. 2 is a cross-sectional view of another embodiment of the optical fiber sensor according to the present invention cut along a plane perpendicular to the axial direction of the optical fiber. As shown in FIG. 2, the optical fiber sensor 11 includes an optical fiber 10, a light emitting layer 7, and a protective layer 8. The optical fiber 10 includes a core layer 4 and a cladding layer 5.
[0063]
The light emitting layer 7 is provided along the central axis (the center in the longitudinal direction) of the optical fiber 10, and the outside of the light emitting layer 7 is surrounded by the core layer 4. The light emitting layer 7 is not particularly limited as long as it has a stress light emitting material whose light emission intensity increases in proportion to the magnitude of stress generated by applying a load from the outside, like the light emitting portion 3. It is not something.
[0064]
That is, the light emitting layer 7 may be a stress light emitting material alone, or the stress light emitting material and other resins (inorganic substances such as alumina and silica, and organic materials such as plastics, resins and rubbers) as in the light emitting part 3. (Material) can also be used as a mixture. In the present embodiment, for example, a powdered mixture of the stress-stimulated luminescent material and a transparent optical resin is used. In this case, it is preferable to select the transparent optical resin having a smaller refractive index than the material of the core layer 4 of the optical fiber 10. For this reason, it is preferable to use polyimide, polyethylene terephthalate, polycarbonate, transparent silicon rubber or the like as the optical resin to be used.
[0065]
Moreover, as a manufacturing method of the light emitting layer 7, a conventionally well-known method can be used and it does not specifically limit. For example, as shown in FIG. 5, it can be manufactured by extrusion or drawing using multiple nozzles. Specifically, a method in which a mixture of a stress luminescent material and an optical resin is introduced from the central nozzle 30 and a resin that becomes the core layer 4 of the optical fiber 10 is introduced from the peripheral nozzle 31 can be mentioned.
[0066]
The light emitting layer 7 is preferably provided along the central axis of the optical fiber 10, but may be provided at a position slightly deviated from the central axis.
[0067]
The light emitting layer 7 may have a single continuous structure or a structure in which a plurality of light emitting layers 7 are intermittently arranged.
[0068]
Furthermore, in the longitudinal direction (axial direction) of the optical fiber 10, a plurality of light emitting layers 7 using stress light emitting materials having different emission spectra can be installed. That is, along the longitudinal direction of the optical fiber 10, a plurality of light emitting layers 7 each having a stress light emitting material having a different emission spectrum can be provided continuously or intermittently. In this case, various light emitting materials having different emission spectra as described in (1-1) can be used for the light emitting layer 7. Furthermore, the plurality of light emitting layers 7 each having a stress light emitting material that emits light having a different emission spectrum can be provided in the optical fiber 10 in any combination and order.
[0069]
In other words, the optical fiber sensor 11 according to the present invention is the one in which the light emitting layer 7 produced by mixing a stress light emitting material that emits light in proportion to the stress in a transparent material is provided at the center of the optical fiber 10. You can also.
[0070]
In other words, it is preferable to provide a plurality of light emitting layers 7 using stress light emitting materials having different emission spectra in the longitudinal direction of the optical fiber sensor 11.
[0071]
(2-2) Function of the optical fiber sensor 11
Since the optical fiber sensor 11 has the above configuration, it has the following functions.
[0072]
The optical fiber sensor 11 is preferably used when performing stress measurement without determining measurement points, for example, when performing stress measurement along a single straight line or curve.
[0073]
That is, when a load is applied to an arbitrary place of the optical fiber sensor 11, the stress-stimulated luminescent material in the light emitting layer 7 emits light in proportion to the magnitude of the stress. This light is transmitted to the core layer 4 of the optical fiber 10. And the magnitude | size of the load applied to the optical fiber sensor 11 is measurable by measuring this light with the photodetector etc. which were connected to the edge part of an optical fiber, for example.
[0074]
Furthermore, as described above, a plurality of light emitting layers 7 each having a stress light emitting material that emits light having different emission spectra can be provided continuously or intermittently along the longitudinal direction of the optical fiber 10.
[0075]
For this reason, for example, by providing a photodetector or the like at the end of the optical fiber sensor 11, information on the light emitted by the stress generated by applying a load (characteristics of emission spectrum, wavelength, frequency, emission intensity, etc.) Can be identified. In other words, it is possible to check at which position the light emitting layer 7 emits light, and to specify the position where the load is applied to the optical fiber sensor 11. In addition, even when a load is applied to the optical fiber sensor 11 at a plurality of positions at the same time, by similarly analyzing light information such as an emission spectrum, the magnitude and application position of stress and load can be easily separated. Can be specified.
[0076]
Further, like the optical fiber sensor 1, the optical fiber sensor 11 does not require a special power supply device to drive the sensor, and can be used in a flammable environment. In addition to being not affected by electromagnetic noise, the laser light can be used for remote measurement of stress without being always incident.
[0077]
The optical fiber sensor 11 can be used for continuous shape change measurement. For this reason, as a concrete usage method of the optical fiber sensor 11, for example, it can be used for monitoring a change (distortion or the like) of the shape of the ground or a building.
[0078]
[Embodiment 3]
A stress measuring device using the optical fiber sensor 1 or the optical fiber sensor 11 will be described below.
[0079]
(3) Stress measuring device 20
(3-1) Configuration of the stress measurement device 20
The means for measuring stress in the present invention may be a stress measurement system that uses an optical fiber sensor, light detection means, and a computer that functions as stress measurement means. Specifically, for example, the stress measuring device 20 shown in FIG. 3 can be mentioned.
[0080]
The stress measuring device 20 using the optical fiber sensor 1 or the optical fiber sensor 11 described above will be described below with reference to FIG. However, the present invention is not limited to this.
[0081]
FIG. 3 is a block diagram showing a configuration of an embodiment of the stress measuring apparatus according to the present invention. As shown in FIG. 3, the stress measuring device 20 includes an optical fiber sensor 1 (or optical fiber sensor 11), a light detection unit 2, a computer 21, a monitor 24, and a display unit 25.
[0082]
The optical fiber sensor 1 or the optical fiber sensor 11 converts an externally applied stress into an optical signal.
[0083]
The light detection unit 2 is a light detection unit for detecting light transmitted from the optical fiber 10. Specifically, the photodetection unit 2 includes a photodetection device such as a conventionally known photodiode, phototransistor, CCD (charge coupled device), photomultiplier tube, and the like. The detection result is not particularly limited as long as the detection result such as the detected light intensity and the emission spectrum is output as a mechanical operation such as an electric signal or a pen movement.
[0084]
The light detection unit 2 can also separate and detect the light emitted from the optical fiber sensor 11 described above for each feature of the emission spectrum. Specifically, the light detection unit 2 can recognize the wavelength, frequency, and the like of light, classify the light according to the characteristics of the emission spectrum, and output the light as an electric signal or the like.
[0085]
In addition, a reflection part can also be provided in the edge part which does not provide the light detection part 2 among the edge parts of the optical fiber 10 in the optical fiber sensor 11, or the light detection part 2 in both the edge parts of the optical fiber 10 in the optical fiber sensor 11. Can also be provided. In this case, the light generated by the applied stress is not emitted to the outside, and the magnitude of the load applied to the optical fiber sensor 11 can be measured more accurately and the position where the load is applied can be specified more accurately. Can do.
[0086]
The computer 21 may function as a stress measurement unit and includes at least a calculation unit 22 and a memory (storage unit) 23. That is, the value of the applied load is processed by the computer 21 including the calculation unit 22 and the memory 23 and is displayed via the display unit 25.
[0087]
More specifically, the calculation unit 22 calculates the load applied to the optical fiber sensor 1 (or the optical fiber sensor 11) based on the electrical signal sent from the light detection unit 2. Further, the calculation unit 22 controls the operation of the stress measurement device 20. Specifically, control information is output from the calculation unit 22 to each means of the light detection unit 2, the monitor 24, the memory 23, and the display unit 25. Based on this control information, the above-described units operate in cooperation, whereby the entire stress measuring device 20 operates.
[0088]
Moreover, the specific structure of the calculating part 22 is not specifically limited, A conventionally well-known calculating means is used suitably. Specifically, any configuration that functions as a central processing unit (CPU) of a computer and that operates according to a computer program is preferable. That is, the calculation unit 22 performs a calculation for measuring the magnitude, position, etc. of the load applied to the optical fiber sensor 1 (or the optical fiber sensor 11) based on a signal sent from the light detection unit 2 by the CPU according to the computer program. It only needs to be executed.
[0089]
Specifically, for example, information such as the material of the light emitting layer 7 provided in the optical fiber sensor 11, the emission spectrum of the light emitted when a load is applied, the position, and the like are previously input to the computer 21, and stored in the memory 23. By storing the data, the calculation unit 22 can analyze which position the light emitting layer 7 emits light based on the electrical signal from the light detection unit 2, and a load is applied to the optical fiber sensor 11. It is possible to easily specify the position where the stress due to.
[0090]
Information can be input to the computer 21 via an input unit (not shown). The input unit is not particularly limited as long as information related to the operation of the stress measuring device 20 can be input, and conventionally known input means such as a keyboard, a tablet, or a scanner can be suitably used. Further, for example, information such as the above-described stress measurement result and position specifying result can be processed by an input from the input unit.
[0091]
The memory 23 stores various information (control information, light emission intensity, light emission spectrum characteristics, other information, etc.) used in the stress measuring device 20. Specifically, for example, semiconductor memories such as RAM and ROM, magnetic disks such as floppy disks and hard disks, disk systems of optical disks such as CD-ROM / MO / MD / DVD, IC cards (including memory cards) / light Various conventionally known storage means such as a card system such as a card can be suitably used.
[0092]
In addition, the memory 23 may be integrated with the stress measuring device 20 to be a single device, but may be a separate external storage device, and further integrated. The memory 23 and the external storage device may be both provided. For example, the integrated memory 23 may be a built-in hard disk or a floppy disk drive, a CD-ROM drive, a DVD-ROM drive, etc. incorporated in the device, and the external storage device may be an external hard disk or an external drive. Examples of the above-mentioned various disk drives.
[0093]
The monitor 24 displays the light emission intensity of light emitted from the light emitting unit 3 in the optical fiber sensor 1 or the light emitting layer 7 in the optical fiber sensor 11 based on the signal from the light detection unit 2. The display unit 25 displays information processed by the computer 21 (for example, a stress value (stress value), an applied load value, a position where a load is applied, etc.).
[0094]
Specifically, the monitor 24 and the display unit 25 are not particularly limited, although various display devices such as a known CRT display and a liquid crystal display are preferably used.
[0095]
Moreover, the stress measuring device 20 may include a printing unit (not shown). The printing section records (prints and forms images) various information that can be displayed on the monitor 24 and the display section 25 on a recording material such as PPC paper. Specifically, known image forming apparatuses such as an ink jet printer and a laser printer are preferably used, but are not particularly limited.
[0096]
Note that the monitor 24, the display unit 25, and the printing unit can be collectively expressed as output means. That is, the monitor 24 and the display unit 25 are means for outputting various types of information by soft copy, and the printing unit is a unit for outputting various types of information by hard copy. Therefore, the output means used in the present invention is not limited to the monitor 24, the display unit 25, and the printing unit, and may include other output means.
[0097]
Furthermore, in FIG. 4, the block diagram which shows the structure of other embodiment of the stress measuring device 20 is shown. That is, for example, as shown in FIG. 4, the stress measuring device 20 may include a communication unit 26 so that various types of information can be input / output via a communication network including the Internet.
[0098]
The communication unit 26 is connected to a communication network and can transmit and receive various types of information. In FIG. 4, a stress measuring device 20, a personal computer (PC) 61, and a server 62 on the same premises are connected to a communication line 60 to form a bus-type LAN (local area network). It is also connected to a PC 61 in another area via the Internet.
[0099]
The specific configuration of the communication unit 26 is not particularly limited, and a known LAN card, LAN board, LAN adapter, modem, or the like can be suitably used.
[0100]
As the PC 61, a known personal computer equipped with a communication means such as a modem can be suitably used, and the PC 61 is not limited to a desktop type or a notebook type. The PC 61 has a basic configuration including a display unit such as a CRT display or a liquid crystal display and an input unit such as a keyboard or a mouse. For convenience of explanation, a display unit and an input unit (not shown) provided in the PC 61 are expressed as a PC display unit / PC input unit.
[0101]
The PC 61 may be provided with hardware (for example, various input means such as a scanner and various output means such as a printer) that can be externally attached to a general personal computer.
[0102]
The specific configuration of the server 62 is not particularly limited as long as it is a computer that can provide services to the PC 61 and the stress measurement device 20 that are clients constituting the LAN. Further, the server 62 may also serve as a database server or a file server.
[0103]
The specific configuration of the communication line 60 is not particularly limited, and a conventionally known general communication line can be used. Also, the type of LAN constructed using this communication line 60 is not limited to the bus type, and may be a conventionally known type such as a star type or a ring type.
[0104]
Although not shown, the LAN may include other terminals such as a shared printer. In addition, although not shown, the communication network including the LAN may include various portable information terminals that can communicate.
[0105]
In the network configured as described above, for example, after the stress measurement device 20 measures the stress generated by applying a load to the optical fiber sensor 1 (or the optical fiber sensor 11), the measurement result is simply stored in the stress measurement device 20 ( In other words, it can be transmitted not only on the monitor 24, the display unit 25, etc.) but also to the PC 61 via the LAN. In the PC 61, the result obtained from the stress measuring device 20 can be displayed on the PC display unit or printed by the printer, and further, the measurement result of the stress described above by the input from the PC input unit, Information such as the position identification result can also be processed.
[0106]
That is, the communication unit 26 functions not only as a communication unit but also as an input unit of the stress measurement device 20. In particular, information related to the measurement of the load applied to the optical fiber sensor 1 (or the optical fiber sensor 11) at a remote location away from the location where the stress measuring device 20 is located using the PC 61 via the Internet. When transmitting (for example, emission intensity, emission spectrum, etc.) or receiving a measurement result, it is possible to provide a service for providing stress measurement to an arbitrary customer.
[0107]
Further, when the PC 61 is connected to the stress measuring device 20 via the LAN, for example, if there is one stress measuring device 20 in a research facility or the like, other researchers can connect via the information terminal such as the PC 61. The stress measuring device 20 can be shared. Therefore, the present invention can be implemented more efficiently.
[0108]
Further, when the server 62 also serves as a database server or a file server, the result of stress measurement performed via the communication network can be accumulated in the server 62 via the communication network. As a result, it becomes possible to make more effective use of stress measurement results and the like.
[0109]
In addition, in the present invention, the stress measurement and the like in the present invention can be implemented by a program on a computer. However, the recording medium for recording the program can be downloaded from a communication network. In particular, a medium carrying a program is also included. For example, if a stress measurement program is recorded in the recording unit of the server 62, the stress measurement device 20 may download and use the stress measurement program from the server 62 as appropriate. However, when the stress measurement device 20 downloads a program from the communication network, the download program is stored in the stress measurement device 20 main body in advance or installed from another recording medium. .
[0110]
Furthermore, when connected to the server 62 via a communication network like the PC 61, the PC 61 itself can be used as the stress measuring device 20 by downloading a stress measurement program from the server 62. .
[0111]
(3-2) Functions of the stress measuring device 20
Since the stress measuring device 20 according to the present invention has the above configuration, it has the following functions.
[0112]
In the stress measuring device 20 having the optical fiber sensor 1 described above, when a load is applied from the outside to the distal end portion of the optical fiber sensor 1, the stress luminescent material of the light emitting portion 3 emits light in proportion to the magnitude of the stress. discharge. This light is transmitted directly and / or after being reflected by the reflector 6 to the core layer 4 of the optical fiber 10.
[0113]
Then, this light is detected by the light detection unit 2 attached to the end of the optical fiber sensor 1 and sent to the computer 21 as an electrical signal (light information such as light emission intensity). Next, the computer 21 uses the arithmetic unit 22 and the memory 23 to measure the magnitude of the stress based on the electrical signal information from the light detection unit 2.
[0114]
Similarly, in the stress measuring device 20 having the optical fiber sensor 11, when a load is applied to the optical fiber sensor 11 from the outside, the stress light emitting material of the light emitting layer 7 emits light in proportion to the magnitude of the stress. This light is transmitted to the core layer 4 of the optical fiber 10.
[0115]
Then, this light is detected by the light detection unit 2 attached to the end of the optical fiber sensor 11 and sent to the computer 21 as an electrical signal (light information such as light emission intensity). Next, the computer 21 uses the arithmetic unit 22 and the memory 23 to measure the magnitude of the stress based on the electrical signal information from the light detection unit 2.
[0116]
At this time, when the optical fiber sensor 11 is provided with a plurality of light emitting layers 7 formed using stress luminescent materials that emit different emission spectra, when the load is applied to the optical fiber sensor 11, the load is reduced. Stress is generated in the light emitting layer 7 provided at the applied position, and light is emitted from the stress light emitting material in the light emitting layer 7.
[0117]
This light is sent to the core layer 4 of the optical fiber 10 and detected by the light detection unit 2. At this time, the light detection unit 2 classifies the light according to the characteristics of the light (emission spectrum, frequency, wavelength, etc.) and sends the light to the computer 21 as an electrical signal.
[0118]
The computer 21 can analyze the position where the light is emitted from the light emitting layer 7 based on the electric signal using the calculation unit 22 and the memory 23, and can specify the position where the load is applied.
[0119]
In addition, the stress measuring apparatus 20 can separately identify the magnitude and application position of each load by analyzing the emission spectrum or the like, even when loads are simultaneously applied to a plurality of positions. .
[0120]
Therefore, the stress measuring device 20 does not require a special power supply device for driving the sensor, and can be used in a flammable environment. In addition to being not affected by electromagnetic noise, it is possible to remotely measure stress without constantly injecting laser light.
[0121]
Moreover, it is preferable to use the stress measuring device 20 having the optical fiber sensor 1 when measuring stress by determining measurement points. For this reason, it can utilize for a medical test | inspection and treatment, for example by using for the apparatus which has a catheter used for endovascular treatment etc. It can also be used for disaster relief, inspection and maintenance without entering and disassembling complex machines and piping.
[0122]
Moreover, it is preferable to use the stress measuring device 20 having the optical fiber sensor 11 when performing stress measurement without defining measurement points, for example, when performing stress measurement along a single straight line or curve. That is, the stress measurement device 20 having the optical fiber sensor 11 can be used for continuous shape change measurement. For this reason, for example, it can be used for monitoring changes in the shape (such as distortion) of the ground and buildings.
[0123]
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and can be obtained by appropriately combining technical means disclosed in different embodiments. Embodiments are also included in the technical scope of the present invention.
[0124]
【The invention's effect】
As described above, the optical fiber sensor of the present invention is provided with the light emitting part having the stress light emitting material whose light emission intensity increases in proportion to the magnitude of the stress at the end of the optical fiber, and the light emitting part and the light emitting part. A reflection part for reflecting the light emitted from the light emitting part is formed on the surface of the light emitting part other than the coupling part with the optical fiber. The light emitting portion has a three-dimensional shape, and the light emitting portion is formed so as to be in contact with the end face of the core layer of the optical fiber and not in contact with the end face of the cladding layer. It is the composition that there is.
[0125]
Therefore, it is not necessary to always enter the laser beam, and the optical noise sensor is excellent in electromagnetic noise resistance and explosion resistance, and an optical fiber sensor capable of remotely detecting the applied load can be configured. In addition, the optical fiber sensor can be further downsized, and the cost can be reduced.
[0126]
Moreover, it is more preferable that the surface shape of the light emitting part other than the coupling part between the light emitting part and the optical fiber is a parabolic shape.
[0127]
According to said structure, there exists an effect that the light generate | occur | produced by the stress which arises in a light emission part can be sent out via an optical fiber more efficiently.
[0128]
Moreover, it is more preferable that the light emitting portion includes a stress light emitting material and an optical resin.
[0129]
According to said structure, optical resin can be used as a kind of binder of stress luminescent material. For this reason, there exists an effect that a light emission part can be shape | molded in arbitrary shapes and the sending efficiency of light can be improved.
[0130]
Further, the stress measuring device according to the present invention includes a light detection unit for detecting light emitted from the light emitting unit at an end of the optical fiber of the optical fiber sensor other than the end provided with the light emitting unit. And a stress measurement unit for measuring the magnitude of stress based on the information on the light detected by the light detection unit.
[0131]
According to the above configuration, the stress measuring device does not need a special power supply device to drive the sensor, is not affected by electromagnetic noise, and is also constantly irradiated with laser light. The stress can be measured remotely without doing so. For this reason, it is possible to reduce the size of the stress measuring device and to reduce the cost.
[0132]
In order to solve the above problems, an optical fiber sensor according to the present invention emits light having a stress-stimulated luminescent material whose light emission intensity increases in proportion to the stress along the central axis of the optical fiber. Layer is provided The light emitting layer is provided at the center of the optical fiber. It is the composition that there is.
[0133]
According to said structure, the said optical fiber sensor can be utilized when performing stress measurement without defining a measurement point, for example, when performing stress measurement along a straight line or a curve. For this reason, there exists an effect that it can utilize for measuring the continuous applied stress (distortion etc.) which is not measurement of a point.
[0134]
In addition, it is not necessary to always enter the laser beam, and it is excellent in electromagnetic noise resistance and explosion-proof properties, and it is possible to configure an optical fiber sensor that can remotely detect the applied load. In addition, the optical fiber sensor can be further downsized, and the cost can be reduced.
[0135]
The optical fiber sensor may be configured such that a plurality of the light emitting layers are provided in the longitudinal direction of the optical fiber, and each of the light emitting layers has a stress light emitting material having a different emission spectrum. .
[0136]
According to said structure, there exists an effect that the position and magnitude | size to which the load was applied can be specified by identifying the characteristic of the emission spectrum of the light discharge | released from stress luminescent material.
[0137]
In addition, the stress measurement device according to the present invention includes a light detection unit for detecting light emitted from the light emitting layer at the end of the optical fiber in the optical fiber sensor. A stress measuring unit is provided for measuring and specifying the magnitude of the applied load and / or the position of the applied load based on the detected light information.
[0138]
According to said structure, the stress of the said light emitting layer can be calculated and the applied load can be measured.
[0139]
Moreover, based on the information (light emission spectrum, wavelength, frequency, etc.) of the light detected by the light detection part, the stress measurement part can specify the position of the load applied to the optical fiber sensor.
[0140]
According to the above configuration, the stress measuring device does not need a special power supply device to drive the sensor, is not affected by electromagnetic noise, and is also constantly irradiated with laser light. The stress can be measured remotely without doing so. For this reason, it is possible to reduce the size of the stress measuring device and to reduce the cost.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of the vicinity of a light emitting unit 3 that is a characteristic part of an embodiment of an optical fiber sensor according to the present invention, cut along a plane along the axial direction of an optical fiber.
FIG. 2 is a cross-sectional view of an optical fiber of another embodiment of the optical fiber sensor according to the present invention cut along a plane perpendicular to the axial direction.
FIG. 3 is a block diagram showing a configuration of an embodiment of a stress measuring apparatus according to the present invention.
FIG. 4 is a block diagram showing a configuration of another embodiment of the stress measurement device according to the present invention.
FIG. 5 is an explanatory view showing an example of a method for producing a light emitting layer of an optical fiber sensor according to the present invention.
[Explanation of symbols]
1 Optical fiber sensor
2 Photodetector
3 Light emitting part
3a joint
4 Core layer
5 Clad layer
6 Reflector
7 Light emitting layer
8 Protective layer
10 Optical fiber
10a end
11 Optical fiber sensor
20 Stress measuring device
21 computer
22 Calculation unit
23 memory
24 Monitor
25 Display section
26 Communication Department
60 Communication line
61 PC
62 servers

Claims (7)

At the end of the optical fiber is provided with a light emitting part having a stress light emitting material whose light emission intensity increases in proportion to the magnitude of the stress,
On the surface of the light emitting part other than the coupling part between the light emitting part and the optical fiber, a reflecting part for reflecting the light emitted from the light emitting part is formed ,
The light emitting part has a three-dimensional shape,
Furthermore, the light emitting section is formed so as to be in contact with the end face of the core layer of the optical fiber and not in contact with the end face of the clad layer .   2. The optical fiber sensor according to claim 1, wherein a shape of a surface of the light emitting portion other than a coupling portion between the light emitting portion and the optical fiber is a parabolic shape.   The optical fiber sensor according to claim 1, wherein the light emitting unit includes a stress light emitting material and an optical resin. The optical fiber of the optical fiber sensor according to claim 1, 2, or 3, further comprising a light detection unit for detecting light emitted from the light emitting unit at an end other than the end provided with the light emitting unit. And
A stress measurement device comprising a stress measurement unit for measuring the magnitude of stress based on light information detected by the light detection unit. Inside the optical fiber, a light emitting layer having a stress light emitting material whose light emission intensity increases in proportion to the magnitude of stress is provided along its central axis ,
An optical fiber sensor, wherein the light emitting layer is provided at the center of an optical fiber.   6. The optical fiber sensor according to claim 5, wherein a plurality of the light emitting layers are provided in a longitudinal direction of the optical fiber, and each of the light emitting layers has a stress light emitting material having a different emission spectrum. The optical fiber sensor according to claim 5 or 6, further comprising a light detection unit for detecting light emitted from the light emitting layer at an end of the optical fiber.
A stress measurement unit is provided for measuring and specifying the magnitude of the applied load and / or the position of the applied load based on the information on the light detected by the light detection unit. Stress measuring device.

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