JP2003214907A - Optical fiber sensor - Google Patents
Optical fiber sensorInfo
- Publication number
- JP2003214907A JP2003214907A JP2002015384A JP2002015384A JP2003214907A JP 2003214907 A JP2003214907 A JP 2003214907A JP 2002015384 A JP2002015384 A JP 2002015384A JP 2002015384 A JP2002015384 A JP 2002015384A JP 2003214907 A JP2003214907 A JP 2003214907A
- Authority
- JP
- Japan
- Prior art keywords
- optical fiber
- movable member
- amount
- change amount
- fixing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Landscapes
- Measuring Magnetic Variables (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Optical Transform (AREA)
Abstract
(57)【要約】
【課題】 比較的小さな張力でかつ高い感度で、変位、
荷重、圧力、磁力、加速度等の物理量を高精度に検出す
るとともに、一つのＦＢＧで温度補償もしくは温度変化
による影響を低減する。
【解決手段】 ファイバグレーティング（ＦＢＧ）２が
書き込まれた光ファイバ１の両端部は、第１および第２
の固定部材３，４に固定されている。これら第１および
第２の固定部材３，４は不動部材６に不動作状態で固定
されている。光ファイバ１の中央に固定した第１の可動
部材５には、光ファイバ１の軸線方向と直交する方向に
被測定物からの物理量が与えられる。光ファイバ１の張
力が変化し、ＦＢＧ２の伸縮を介して、ＦＢＧ２からの
反射光または透過光の波長シフト量として検出手段によ
って検出される。
(57) [Summary] [PROBLEMS] Displacement, with relatively small tension and high sensitivity
Physical quantities such as load, pressure, magnetic force, acceleration, etc. are detected with high accuracy, and the effect of temperature compensation or temperature change is reduced by one FBG. SOLUTION: Both ends of an optical fiber 1 on which a fiber grating (FBG) 2 is written are first and second ends.
Are fixed to the fixing members 3 and 4. The first and second fixing members 3 and 4 are fixed to the immovable member 6 in a non-operating state. The first movable member 5 fixed to the center of the optical fiber 1 is given a physical quantity from the object to be measured in a direction orthogonal to the axial direction of the optical fiber 1. The tension of the optical fiber 1 changes, and is detected by the detecting means as a wavelength shift amount of reflected light or transmitted light from the FBG 2 via expansion and contraction of the FBG 2.
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ひずみ、変位、荷
重、圧力、磁力、加速度、などの物理量検出を行う光フ
ァイバセンサに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber sensor for detecting physical quantities such as strain, displacement, load, pressure, magnetic force and acceleration.
【０００２】[0002]
【従来の技術】最近、ファイバグレーティング（Ｆｉｂ
ｅｒ Ｂｒａｇｇ Ｇｒａｔｉｎｇ：以下ＦＢＧと略
す）と称するファイバ型検出素子を用いたひずみセンサ
や温度センサの開発が進められている。すなわち、入力
する光の進行方向にグレーティング（回折格子）を構成
し、温度やひずみによって光ファイバが伸縮した際、光
ファイバに書き込まれたグレーティングのピッチが変化
する。上述したセンサは、その変化に応じてグレーティ
ングからブラッグ反射する光のピーク波長（ブラッグ波
長という）が変化すること、あるいはグレーティングを
透過するディップ光の中心波長である光のスペクトル
（これもブラック波長という）が変化することを利用し
たものである。2. Description of the Related Art Recently, a fiber grating (Fib
er Bragg Grating: hereinafter abbreviated as FBG), a strain sensor and a temperature sensor using a fiber type detection element are being developed. That is, a grating (diffraction grating) is formed in the traveling direction of the input light, and when the optical fiber expands or contracts due to temperature or strain, the pitch of the grating written in the optical fiber changes. In the sensor described above, the peak wavelength of the light that is Bragg-reflected from the grating (called the Bragg wavelength) changes according to the change, or the spectrum of the light that is the central wavelength of the dip light that passes through the grating (also called the black wavelength). ) Is used to change.
【０００３】このグレーティングは、ゲルマニウム(Ge)
を添加した石英ガラスのコアに対してコヒーレントな紫
外レーザ光を照射することで、所望の部分に光誘起屈折
率変化を引き起こし、屈折率の縞を形成することによっ
て作製される。光ファイバのコアに書かれたグレーティ
ングのピッチをΛ、グレーティングが書き込まれている
部分における光ファイバのコアの実効屈折率をｎとする
と、ブラック波長λＢとの関係は数式１により示され
る。This grating is made of germanium (Ge)
By irradiating a coherent ultraviolet laser beam to the core of the silica glass to which is added, a photo-induced refractive index change is caused in a desired portion to form a refractive index fringe. Assuming that the pitch of the grating written on the core of the optical fiber is Λ and the effective refractive index of the core of the optical fiber in the portion where the grating is written is n, the relationship with the black wavelength λB is represented by Formula 1.
【０００４】λＢ＝２・ｎ・Λ …数式１ΛB = 2 · n · Λ Equation 1
【０００５】ＦＢＧのひずみに対する応答性は数式２よ
り示される。すなわち与えられたひずみ量をΔεとし、
ブラック波長をλＢ、そのシフト量をΔλとするとその
間には以下の関係が成り立つ。The response of the FBG to strain is expressed by Equation 2. That is, the given strain amount is Δε,
When the black wavelength is λB and the shift amount is Δλ, the following relationship is established between them.
【０００６】ΔλＢ／λＢ＝(1-Pe)Δε …数式２ΔλB / λB = (1-Pe) Δε Equation 2
【０００７】ここでPeはポッケルス係数でおよそ０.２
２であり、使用する波長帯が１５５０ｎｍであるときに
は、１マイクロストレインあたりのひずみ量はおよそ
０.００１２ｎｍである。Here, Pe is a Pockels coefficient of about 0.2.
2, and when the wavelength band used is 1550 nm, the strain amount per microstrain is about 0.0012 nm.
【０００８】ここでマイクロストレインとは１×１０-6
ひずみ、たとえば１ｍの材料が０.００１ｍｍ変形した
ひずみである。Here, the micro strain is 1 × 10 -6
The strain is, for example, a strain in which 1 m of material is deformed by 0.001 mm.
【０００９】次にＦＢＧの温度に対する応答性は数式３
により示される。すなわち与えられた温度変化量をΔＴ
とし、ブラック波長をλＢ、そのシフト量をΔλとする
とその間には以下の数式３の関係が成り立つ。Next, the responsiveness of the FBG to the temperature is expressed by Equation 3
Indicated by. That is, the given temperature variation is ΔT
And the black wavelength is λB and the shift amount is Δλ, the relationship of the following mathematical formula 3 is established between them.
【００１０】 ΔλＢ／λＢ＝(α＋ξ)ΔＴ …数式３[0010] ΔλB / λB = (α + ξ) ΔT ... Equation 3
【００１１】ここでαは光ファイバの線膨張係数であ
り、ξは屈折率の温度変化を表す熱光学係数で、この係
数は温度とGe濃度によって変化する。使用する波長帯が
１５５０ｎｍで、室温付近の値はαは０.５５×１０-6
／℃であり、ξは約８.０×１０ -6／℃である。Where α is the coefficient of linear expansion of the optical fiber.
Where ξ is the thermo-optic coefficient that represents the change in refractive index with temperature.
The number varies with temperature and Ge concentration. The wavelength band used
At 1550 nm, at room temperature, α is 0.55 × 10-6
/ ° C and ξ is about 8.0 × 10 -6/ ° C.
【００１２】従来から金属の伸縮を利用し、変位、荷
重、圧力の物理量に変換する変換器としてはひずみゲー
ジを利用する方法がある。これは、弾性体である金属体
にひずみゲージを接着等で貼りつけて、上記物理量を計
測するものであって、金属の弾性領域は１０００マイク
ロストレイン程度が限度となる。Conventionally, there has been a method of utilizing a strain gauge as a transducer which utilizes the expansion and contraction of metal and converts it into physical quantities of displacement, load and pressure. This is a method in which a strain gauge is attached to an elastic metal body by adhesion or the like to measure the physical quantity, and the elastic region of the metal is limited to about 1000 microstrain.
【００１３】この場合、ひずみゲージ式変換器において
は、ホイートストンブリッジを構成することにより４０
００マイクロストレイン程度の感度が得られる。これに
対して光ファイバを直接物体に接着して変換器とした場
合には、均一なひずみを必要とし、かつひずみの大きさ
が金属の弾性領域内の制限があるため、感度も１０００
マイクロストレインが限度である。In this case, in the strain gauge type transducer, by constructing a Wheatstone bridge, 40
A sensitivity of about 00 microstrain can be obtained. On the other hand, when an optical fiber is directly bonded to an object to form a transducer, a uniform strain is required, and the magnitude of the strain is limited within the elastic region of the metal.
Micro strain is the limit.
【００１４】これに対し本願の発明者は、特開２００１
−２２１６１５号において、直線性および感度を上げる
ために直接ＦＢＧが書き込まれている光ファイバの両端
を固定部で保持し、一方の固定部にかかる物理変化量を
光ファイバに張力をくわえることによって、ひずみを形
成する方法を提案している。On the other hand, the inventor of the present application has disclosed that
No. 221615, by fixing both ends of the optical fiber in which the FBG is directly written in order to improve linearity and sensitivity, and by applying a physical change amount applied to one of the fixed parts to the optical fiber, A method of forming strain is proposed.
【００１５】この方法ではＦＢＧが書き込まれた光ファ
イバの被覆に熱硬化樹脂あるいは熱可塑性の弾性樹脂を
用いてこれを固定部に接着し、その固定部間に直接的に
張力を加えるか、あるいはばねやてこを介して間接的に
張力を加える方法が記載されている。そして、ＦＢＧの
部分では５０００マイクロストレイン以上の高いひずみ
出力が得られることが開示されており、これにより広範
囲に物理量の計測が可能となるものである。In this method, a thermosetting resin or a thermoplastic elastic resin is used for the coating of the optical fiber in which the FBG is written, and this is adhered to the fixed portions, and tension is directly applied between the fixed portions, or A method of indirectly applying tension via a spring or lever is described. Further, it is disclosed that a high strain output of 5000 microstrain or more can be obtained in the FBG portion, which makes it possible to measure a physical quantity in a wide range.
【００１６】[0016]
【発明が解決しようとする課題】しかしながら、上述し
た従来の光ファイバセンサにおいては、一方の固定部に
かかる物理変化量をＦＢＧが書き込まれた光ファイバの
軸線方向に加える方法としているために、１０００マイ
クロストレインの出力を得るためには約１００ｇの張力
を必要としていた。また、てこを利用して力を拡大する
方法では、てこの支点の摩擦が影響して精度が落ちると
いう問題があった。However, in the above-mentioned conventional optical fiber sensor, the method of adding the physical change amount applied to one fixed portion in the axial direction of the optical fiber in which the FBG is written is 1000. About 100 g of tension was required to obtain the output of the microstrain. Further, in the method of expanding the force using the lever, there is a problem that the friction of the lever fulcrum affects and the accuracy is lowered.
【００１７】本発明は上記した従来の問題に鑑みなされ
たものであり、第１の目的は、比較的小さな張力でかつ
高い感度で、変位、荷重、圧力、磁力、加速度等の物理
量を高精度に検出することにある。また、第２の目的
は、一つのＦＢＧで温度補償もしくは温度変化による影
響を低減することにある。The present invention has been made in view of the above-mentioned conventional problems. A first object of the present invention is to accurately measure physical quantities such as displacement, load, pressure, magnetic force, and acceleration with relatively small tension and high sensitivity. To detect. A second purpose is to reduce the influence of temperature compensation or temperature change with one FBG.
【００１８】[0018]
【課題を解決するための手段】この目的を達成するため
に、請求項１に係る発明は、ＦＢＧが書き込まれた光フ
ァイバと、この光ファイバの両端部を固定する第１の固
定部材および第２の固定部材と、これら第１および第２
の固定部材を固定する不動部材と、前記光ファイバの前
記ＦＢＧを含まない両端部間に光ファイバを介在した第
１の可動部材と、この第１の可動部材に光ファイバの軸
線方向とある角度を有する方向に物理変化量を与える被
測定物とにおいて、この被測定物から与えられる物理変
化量を光ファイバの張力変化量に変換し、前記ＦＢＧの
伸縮を介して、ＦＢＧからの反射光または透過光の波長
シフト量として検出する検出手段とを備えたものであ
る。光ファイバの両端を軸線方向に引っ張るよりも、光
ファイバの両端を固定し、軸線方向とは垂直あるいはそ
れに近い角度で引っ張った方が、小さな力で光ファイバ
により大きな張力変化をもたらすので、したがって物理
量検出の感度向上が期待できる。In order to achieve this object, the invention according to claim 1 provides an optical fiber in which an FBG is written, a first fixing member for fixing both ends of the optical fiber, and a first fixing member. 2 fixing members and these first and second fixing members
Fixed member for fixing the fixed member, a first movable member having an optical fiber interposed between both ends of the optical fiber not including the FBG, and an angle with the axial direction of the optical fiber in the first movable member. And an object to be measured which gives a physical change amount in a direction having a value, a physical change amount given from the object to be measured is converted into a tension change amount of an optical fiber, and the reflected light from the FBG or And a detecting means for detecting the wavelength shift amount of the transmitted light. Rather than pulling both ends of the optical fiber in the axial direction, fixing both ends of the optical fiber and pulling it at an angle perpendicular to the axial direction or at an angle close to it causes a larger tension change in the optical fiber with a small force, and therefore a physical quantity The detection sensitivity can be expected to improve.
【００１９】また、請求項２に係る発明は、請求項１に
係る発明において、自重でたるませた状態で光ファイバ
を前記第１の固定部材と前記第２の固定部材との間に固
定したものである。物理量変化によって光ファイバは引
き伸ばされ、光ファイバのたるみは解消するように、あ
るいはさらにたるむようになるが、このときでも光ファ
イバには張力変化をもたらすため、したがって光ファイ
バがたるんでいる状態でもＦＢＧの伸縮を介して物理変
化量を検出することができる。According to a second aspect of the invention, in the first aspect of the invention, the optical fiber is fixed between the first fixing member and the second fixing member while being slackened by its own weight. It is a thing. The change in the physical quantity causes the optical fiber to be stretched, so that the slack of the optical fiber is eliminated or becomes more slack. However, even at this time, the optical fiber causes a change in tension. Therefore, even when the optical fiber is slack, the FBG The amount of physical change can be detected through expansion and contraction.
【００２０】また、請求項３に係る発明は、請求項１に
係る発明において、予め張力を加えた状態で光ファイバ
を前記第１の固定部材と前記第２の固定部材との間に固
定したものである。したがって、光ファイバの張力の遊
びをなくした状態での検出が可能になる。According to a third aspect of the present invention, in the invention according to the first aspect, the optical fiber is fixed between the first fixing member and the second fixing member while pretensioned. It is a thing. Therefore, it is possible to perform detection in a state where the tension play of the optical fiber is eliminated.
【００２１】また、請求項４に係る発明は、ＦＢＧが書
き込まれた光ファイバと、この光ファイバの一端部を固
定する第１の固定部材と、光ファイバの他端部を磁性体
で固定した第２の可動部材と、この第２の可動部材に磁
力変化を与える被測定物とにおいて、この被測定物から
与えられる磁力変化量を光ファイバの張力変化量に変換
し、前記ＦＢＧの伸縮を介して、ＦＢＧからの反射光ま
たは透過光の波長シフト量として検出する検出手段とを
備えたものである。したがって、磁力変化を、直接光フ
ァイバの張力変化に変化し、物理量として磁力の変化を
検出できる。Further, in the invention according to claim 4, the optical fiber in which the FBG is written, the first fixing member for fixing one end of the optical fiber, and the other end of the optical fiber are fixed with a magnetic material. In the second movable member and the object to be measured that changes the magnetic force to the second movable member, the amount of change in the magnetic force applied from the object to be measured is converted into the amount of change in the tension of the optical fiber to expand or contract the FBG. And a detection means for detecting the amount of wavelength shift of the reflected light or the transmitted light from the FBG. Therefore, the change in the magnetic force is directly changed to the change in the tension of the optical fiber, and the change in the magnetic force can be detected as a physical quantity.
【００２２】また、請求項５に係る発明は、請求項４に
係る発明において、前記第２の可動部材と非接触状態で
配置された第３の可動部材と、この第３の可動部材に物
理変化量を与える被測定物とにおいて、これら第２およ
び第３の可動部材を共に磁性体で形成するか、または一
方を磁性体で形成し他方を導体で形成し、前記第３の可
動部材に与えられる物理変化量を、前記第２の可動部材
に与えられる磁力変化量に変えて、前記被測定物から与
えられる物理変化量を光ファイバの張力変化量に変換
し、前記ＦＢＧの伸縮を介して、ＦＢＧからの反射光又
は透過光の波長シフト量として検出する検出手段とを備
えたものである。したがって、磁力を利用して、間接的
に磁力以外の他の物理量変化の検出が可能になる。According to a fifth aspect of the present invention, in the invention according to the fourth aspect, the third movable member is disposed in a non-contact state with the second movable member, and the third movable member is physically attached to the third movable member. The second movable member and the third movable member are both made of a magnetic material, or one of them is made of a magnetic material and the other is made of a conductor. The given physical change amount is changed to the magnetic force change amount given to the second movable member to convert the physical change amount given from the object to be measured into a tension change amount of the optical fiber, and through expansion and contraction of the FBG. And a detection means for detecting the wavelength shift amount of the reflected light or the transmitted light from the FBG. Therefore, it is possible to indirectly detect a change in a physical quantity other than the magnetic force by using the magnetic force.
【００２３】また、請求項６に係る発明は、請求項１に
係る発明において、前記第１の可動部材を磁性体で形成
し、この第１の可動部材に磁力変化を与える被測定部と
において、この被測定物から与えられる磁力変化量を光
ファイバの張力変化量に変換し、前記ＦＢＧの伸縮を介
して、ＦＢＧからの反射光又は透過光の波長シフト量と
して検出する検出手段とを備えたものである。したがっ
て、わずかな磁力変化を小さな力で検出できるため、磁
力検出の感度向上が期待できる。According to a sixth aspect of the present invention, in the invention according to the first aspect, the first movable member is formed of a magnetic material, and a portion to be measured which gives a magnetic force change to the first movable member. A detecting means for converting the amount of change in the magnetic force applied from the object to be measured into the amount of change in the tension of the optical fiber, and detecting the amount of wavelength shift of the reflected light or the transmitted light from the FBG through expansion and contraction of the FBG. It is a thing. Therefore, since a slight change in magnetic force can be detected with a small force, it is expected to improve the sensitivity of magnetic force detection.
【００２４】また、請求項７に係る発明は、請求項１に
係る発明において、前記第１の可動部材と非接触状態で
配置された第４の可動部材と、光ファイバの前記第１の
可動部材に光ファイバの軸線方向とある角度を有する方
向に物理変化量を与える被測定物とにおいて、これら第
１および第４の可動部材を共に磁性体で形成するか、ま
たは一方を磁性体で形成し他方を導体で形成し、前記第
４の可動部材に与えられる物理変化量を、前記第１の可
動部材に与えられる磁力変化量に変えて、前記被測定物
から与えられる物理変化量を光ファイバの張力変化量に
変換し、前記ＦＢＧの伸縮を介して、ＦＢＧからの反射
光又は透過光の波長シフト量として検出する検出手段と
を備えたものである。したがって、磁力を利用した、し
かも感度の高い物理量変化の検出が可能になる。According to a seventh aspect of the invention, in the invention according to the first aspect, the fourth movable member arranged in a non-contact state with the first movable member, and the first movable member of the optical fiber. In the object to be measured which gives a physical change amount to the member in a direction having an angle with the axial direction of the optical fiber, both the first and fourth movable members are made of a magnetic material, or one of them is made of a magnetic material. The other is made of a conductor, and the physical change amount given to the fourth movable member is changed to the magnetic force change amount given to the first movable member, so that the physical change amount given from the object to be measured is changed to light. It is provided with a detecting means for converting into a fiber tension change amount and detecting it as a wavelength shift amount of reflected light or transmitted light from the FBG through expansion and contraction of the FBG. Therefore, it is possible to detect a physical quantity change with high sensitivity using magnetic force.
【００２５】また、請求項８に係る発明は、請求項１，
３，６，７に係る発明において、前記第１の固定部材
と、第２の固定部材と、前記第１の固定部材と第２の固
定部材を固定する不動部材と、前記第１の固定部材と第
２の固定部材のうちの少なくともいずれか一方と光ファ
イバとの間に介在させる支持部材とを備え、前記固定部
材および前記支持部材の線膨張係数を前記不動部材の線
膨張係数よりも大きく設定し、かつ支持部材の光ファイ
バの軸線方向の長さを調節し、光ファイバ中のＦＢＧか
らの反射光又は透過光の波長シフト量が温度によって依
存する変化量を補償もしくは低減したものである。した
がって、予め光ファイバに張力が掛けられるものにおい
ては、ＦＢＧ自体が有する温度変化による波長変化量を
補償すること、または低減することが可能になる。The invention according to claim 8 relates to claim 1,
In the invention according to 3, 6, 7, the first fixing member, the second fixing member, the immovable member fixing the first fixing member and the second fixing member, and the first fixing member. And a supporting member interposed between at least one of the second fixing member and the optical fiber, and the linear expansion coefficient of the fixing member and the supporting member is larger than the linear expansion coefficient of the immovable member. By setting and adjusting the length of the supporting member in the axial direction of the optical fiber, the amount of change in the wavelength shift amount of reflected light or transmitted light from the FBG in the optical fiber depending on temperature is compensated or reduced. . Therefore, in the case where tension is applied to the optical fiber in advance, it becomes possible to compensate or reduce the amount of wavelength change due to temperature change of the FBG itself.
【００２６】また、請求項９に係る発明は、請求項１な
いし８に係る発明において、前記可動部材と被測定部材
との間に、付勢手段又は／及びてこ又は／及び滑車を介
在させるとともに、付勢手段の付勢力又は／及びてこ比
を調整自在としたものである。したがって、検出される
物理量の感度を選択的に変換が可能になる。According to a ninth aspect of the invention, in the invention according to the first to eighth aspects, an urging means or / and a lever and / or a pulley are interposed between the movable member and the member to be measured. The urging force of the urging means or / and the lever ratio are adjustable. Therefore, the sensitivity of the detected physical quantity can be selectively converted.
【００２７】[0027]
【発明の実施の形態】図１は本発明の第１の実施の形態
を示すモデル図である。同図に示すように、符号１で示
す光ファイバの一部には、ＦＢＧ２が書き込まれてお
り、光ファイバ１の両端部はそれぞれ第１の固定部材３
と第２の固定部材４に固定され、両固定部材３，４間に
張架されている。光ファイバ１の両固定部材３，４間の
ほぼ中央には、第１の可動部材５が固定されており、上
述したＦＢＧ２は第１の固定部材３と第１の可動部材５
との間に位置付けられている。上述した第１の固定部材
３と第２の固定部材４とが不動部材６に不動作状態で固
定されている。ここでは第１の可動部材５を検出部と
し、この第１の可動部材５は図示を省略した被測定物に
よって物理変化量が与えられることにより移動する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a model diagram showing a first embodiment of the present invention. As shown in the figure, the FBG 2 is written in a part of the optical fiber indicated by reference numeral 1, and both ends of the optical fiber 1 are respectively fixed to the first fixing member 3.
Is fixed to the second fixing member 4 and is stretched between the fixing members 3 and 4. The first movable member 5 is fixed to the optical fiber 1 substantially at the center between the fixed members 3 and 4, and the above-mentioned FBG 2 includes the first fixed member 3 and the first movable member 5.
It is located between and. The first fixing member 3 and the second fixing member 4 described above are fixed to the immovable member 6 in an inoperative state. Here, the first movable member 5 is used as a detection unit, and the first movable member 5 moves when a physical change amount is given by an object to be measured (not shown).
【００２８】すなわち、この検出部５において光ファイ
バ１の軸線方向とほぼ直交する方向に図示を省略した被
測定物からのひずみ、変位、荷重、圧力、加速度等の物
理量変化によって力が与えられると、光ファイバ１の張
力が変化し、ＦＢＧ２が伸縮する。したがって、これが
ＦＢＧ２のグレーティングの周期を変化させ、前記数式
（１）および数式（２）において示した関係に基づい
て、ＦＢＧ２からの反射あるいは透過光においてのブラ
ック波長がシフトされ、図示を省略した検出手段によっ
て物理変化量がブラック波長シフト量として検出され
る。なお、被測定物から加わる力の方向の角度φを光フ
ァイバ１の軸線方向とほぼ直交する方向にしたが、角度
φが０°以外なら何度でもよい。That is, when a force is applied to the detecting section 5 in a direction substantially orthogonal to the axial direction of the optical fiber 1 by a physical quantity change such as strain, displacement, load, pressure, acceleration or the like from the DUT (not shown). , The tension of the optical fiber 1 changes, and the FBG 2 expands and contracts. Therefore, this changes the period of the grating of the FBG2, and the black wavelength in the reflected or transmitted light from the FBG2 is shifted based on the relationship shown in the equations (1) and (2), and the detection not shown in the figure is performed. The physical change amount is detected by the means as the black wavelength shift amount. Although the angle φ in the direction of the force applied from the object to be measured is set to be a direction substantially orthogonal to the axial direction of the optical fiber 1, it may be any number as long as the angle φ is other than 0 °.
【００２９】また、光ファイバ１の第１の固定部材３，
第２の固定部材４，第１の可動部材５で固定される部位
は、予めクリープのない弾性樹脂、例えばポリイミドの
ような熱硬化樹脂で被覆されていることが望ましく、そ
れによって光ファイバが破断するのを防ぎ、物理変化量
がファイバの伸縮に一意的に変換されるようになる。Further, the first fixing member 3 of the optical fiber 1
The portions fixed by the second fixed member 4 and the first movable member 5 are preferably coated beforehand with a creep-free elastic resin, for example, a thermosetting resin such as polyimide, which breaks the optical fiber. The physical change amount is uniquely converted into the expansion and contraction of the fiber.
【００３０】また、第１の可動部材５すなわち検出部
は、第１の固定部材３と第２の固定部材４の中間にある
ことが望ましく、物量変化は光ファイバの軸線方向と直
交する方向（角度φ＝９０°）であることが望ましい。
これにより光ファイバ１に一番大きな張力変化をもたら
し、感度の高い検出が可能となる。It is desirable that the first movable member 5, that is, the detecting portion, is located between the first fixed member 3 and the second fixed member 4, and the change in the physical quantity is in a direction orthogonal to the axial direction of the optical fiber ( It is desirable that the angle φ = 90 °).
This brings about the largest change in tension in the optical fiber 1 and enables highly sensitive detection.
【００３１】ここで、固定部３および固定部４間の光フ
ァイバの長さを２Ｌとし、固定部５に加わる物理量変化
が光ファイバ１の軸線方向と直交する方向にあり、それ
によって生じる支点５の移動量をｓとすると、三角法よ
り光ファイバのひずみとの関係は以下の数式４になる。Here, the length of the optical fiber between the fixed portion 3 and the fixed portion 4 is set to 2 L, and the change in the physical quantity applied to the fixed portion 5 is in the direction orthogonal to the axial direction of the optical fiber 1, and the fulcrum 5 caused thereby. Letting s be the amount of movement of, the relation with the strain of the optical fiber is expressed by the following equation 4 according to trigonometry.
【００３２】 Δε=｛(L2+s2)1/2− L ｝／L …数式４Δε = {(L 2 + s 2 ) 1 / 2 −L} / L Equation 4
【００３３】これを整理すると数式４は以下の数式５で
表される。When this is arranged, the equation 4 is expressed by the following equation 5.
【００３４】s ≒ L・(2Δε)1/2 …数式５S ≈ L · (2Δε) 1/2 ... Equation 5
【００３５】ここで光ファイバ１の軸線方向と直交する
方向にかかる張力Fsと光ファイバの張力と移動量sの関
係は三角法より以下の数式６で表される。Here, the relationship between the tension Fs applied in the direction orthogonal to the axial direction of the optical fiber 1 and the tension of the optical fiber and the movement amount s is expressed by the following equation 6 by trigonometry.
【００３６】 Fs ＝ 2F・sin(tan-1(s/L)) …数式６Fs = 2F · sin (tan −1 (s / L)) Equation 6
【００３７】またsが十分に小さい場合には数式６は数
式７のように省略できる。If s is sufficiently small, Equation 6 can be omitted like Equation 7.
【００３８】Fs ≒ 2Ｆ・s／L …数式７
またフックの法則より光ファイバのヤング率をＥとし、
光ファイバの断面積をＡとすると、数式７は以下の数式
８で表される。Fs≅2F · s / L Equation 7
Also, according to Hooke's law, the Young's modulus of the optical fiber is E,
When the cross-sectional area of the optical fiber is A, Expression 7 is expressed by Expression 8 below.
【００３９】 Fs ＝ 2Ｆ・(2Δε)1/2 ＝2・Δε・Ａ・E・(2Δε)1/2 …数式８Fs = 2F · (2Δε) 1/2 = 2 · Δε · A · E · (2Δε) 1/2 (Equation 8)
【００４０】ここで、前記の通常の光ファイバを引きの
ばした場合と比較してみると、通常では１０００マイク
ロストレインの出力を得るためには約１００ｇの張力を
必要としているのに対してこの方法ではＬを１０ｍｍと
した場合、以上の計算式により１０００マイクロストレ
インの出力を得るためにsはおよそ０.４５ｍｍとなり、
光ファイバとは垂直の向きにかかる張力はおよそ１２ｇ
で済むことになる。これによって低張力での検出が可能
となり、きわめて高い感度の向上が可能である。Here, comparing with the case where the above-mentioned ordinary optical fiber is extended, normally, about 100 g of tension is required to obtain an output of 1000 microstrain, but this In the method, when L is 10 mm, s is about 0.45 mm in order to obtain the output of 1000 microstrain by the above calculation formula,
The tension applied in the direction perpendicular to the optical fiber is about 12g
Will be enough. This makes it possible to detect at low tension, and it is possible to improve extremely high sensitivity.
【００４１】図８には本発明の第１の実施の形態の光フ
ァイバセンサより得られた出力グラフを示している。同
図において１０００マイクロストレインの出力はおよそ
１２ｇであり、ほぼ理論値に近く、わずかな張力で大き
なひずみ値が得られており、理論どおり感度向上されて
いることがわかる。FIG. 8 shows an output graph obtained from the optical fiber sensor according to the first embodiment of the present invention. In the figure, the output of 1000 microstrain is about 12 g, which is close to the theoretical value, and a large strain value is obtained with a slight tension, and it can be seen that the sensitivity is improved as theoretically.
【００４２】図２は本発明の第２の実施の形態を示すモ
デル図である。この第２の実施の形態においては、光フ
ァイバ１に張力を加えなくても、自重でたるませた状態
でも物理量変化の検知が可能になる。同図においてたる
ませた状態の光ファイバ１が第１の固定部材３と第２の
固定部材４に固定されている。FIG. 2 is a model diagram showing the second embodiment of the present invention. In the second embodiment, even if the optical fiber 1 is not tensioned, the physical quantity change can be detected even when the optical fiber 1 is slackened by its own weight. In the figure, the optical fiber 1 in a slackened state is fixed to the first fixing member 3 and the second fixing member 4.
【００４３】計測は物理量と波長変化量を理論的に求め
ることでも可能であるが、最もよい方法はあらかじめそ
の物理変化量を変化させ、そのときの波長変動量の推移
を把握しておくことであり、主にこのような自重たわみ
状態での検出は、微少な物理変化量の検出に利用ができ
る。The measurement can be performed by theoretically obtaining the physical quantity and the wavelength variation, but the best method is to change the physical variation in advance and grasp the transition of the wavelength variation at that time. Therefore, the detection in the state of self-deflection as described above can be mainly used for the detection of a minute physical change amount.
【００４４】また、あらかじめ光ファイバ１に張力をか
けた状態で、第１の固定部材３と第２の固定部材４に固
定することでも物理量を計測でき、このような張力をか
けた状態では、光ファイバ１の張力の遊びをなくすこと
ができるため精度の高い計測が可能になる。The physical quantity can be measured by fixing the optical fiber 1 to the first fixing member 3 and the second fixing member 4 in a state where tension is applied to the optical fiber 1 in advance. Since the play of the tension of the optical fiber 1 can be eliminated, highly accurate measurement becomes possible.
【００４５】図３は本発明の第３の実施の形態を示すモ
デル図である。ＦＢＧ２が書き込まれた光ファイバ１の
一端部が第１の固定部材３に固定され、光ファイバ１の
他端部が第２の可動部材７に固定されている。第１の固
定部材３は図示を省略した不動部材に固定されて不動状
態であり、第２の可動部材７は移動自在であって、第２
の可動部材７は磁石によって代表される磁性体で形成さ
れている。この第２の可動部材７に与える磁力を変化さ
せる図示を省略した被測定物によって光ファイバ１の張
力を変化させ、ＦＢＧ２の伸縮を介して、ＦＢＧからの
反射光または透過光の波長シフト量を図示を省略した検
出手段によって検出する。FIG. 3 is a model diagram showing a third embodiment of the present invention. One end of the optical fiber 1 in which the FBG 2 is written is fixed to the first fixed member 3, and the other end of the optical fiber 1 is fixed to the second movable member 7. The first fixed member 3 is fixed to an immovable member (not shown) and is in an immovable state, the second movable member 7 is movable, and
The movable member 7 is made of a magnetic material represented by a magnet. The tension of the optical fiber 1 is changed by an object to be measured (not shown) that changes the magnetic force applied to the second movable member 7, and the wavelength shift amount of the reflected light or the transmitted light from the FBG is changed through the expansion and contraction of the FBG 2. Detection is performed by a detection means (not shown).
【００４６】なお、磁力によってわずかな張力変化が生
ずれば、この第３の実施の形態は成り立つので、第２の
可動部材７は必ずしも大きく形成する必要はなく、光フ
ァイバ１の表面に磁性箔を取り付けた程度のものでもよ
い。また、この第３の実施の形態においては、磁性体の
極によっては、第２の可動部材７を不動状態とし、第１
の固定部材３を移動自在とし、この第１の固定部材３に
与えられる磁力の変化量を計測するようにしてもよい。If a slight change in tension is generated by the magnetic force, the third embodiment is established. Therefore, the second movable member 7 does not necessarily have to be formed large, and the magnetic foil is formed on the surface of the optical fiber 1. It may be the one attached. In addition, in the third embodiment, the second movable member 7 is immovable depending on the pole of the magnetic body, and
The fixing member 3 may be made movable and the amount of change in the magnetic force applied to the first fixing member 3 may be measured.
【００４７】図４は本発明の第４の実施の形態を示すモ
デル図である。すなわち、この第４の実施の形態は、上
述した第３の実施の形態において、第２の可動部材７と
非接触状態で配置された第３の可動部材８を備え、これ
ら第２および第３の可動部材７，８を共に磁性体で形成
するか、または一方を磁性体で形成し他方を導体で形成
している。このような構成において、第３の可動部材８
に、光ファイバ１の軸線方向、もしくは軸線方向とある
角度を有する方向に被測定物（図示せず）のひずみ、変
位、荷重、圧力、加速度の物理変化量を与える。第２の
可動部材７と第３の可動部材８との距離が変化すること
による磁力変化によって、光ファイバ１に与えられる張
力を変化させ、ＦＢＧ２の伸縮を介してＦＢＧ２からの
反射光又は透過光での波長シフト量として図示を省略し
た検出手段によって検出することができる。FIG. 4 is a model diagram showing a fourth embodiment of the present invention. That is, the fourth embodiment includes the third movable member 8 arranged in a non-contact state with the second movable member 7 in the above-described third embodiment, and the second and third movable members 8 are provided. The movable members 7 and 8 are both made of a magnetic material, or one is made of a magnetic material and the other is made of a conductor. In such a configuration, the third movable member 8
In addition, physical change amounts of strain, displacement, load, pressure and acceleration of the object to be measured (not shown) are given in the axial direction of the optical fiber 1 or in a direction having an angle with the axial direction. The tension applied to the optical fiber 1 is changed by the change in the magnetic force due to the change in the distance between the second movable member 7 and the third movable member 8, and the reflected light or transmitted light from the FBG 2 is expanded or contracted by the FBG 2. It is possible to detect the amount of wavelength shift in (1) by detecting means (not shown).
【００４８】図５は本発明の第５の実施の形態を示すモ
デル図である。この第５の実施の形態が、上述した第１
の実施の形態と異なる点は、第１の可動部材５を磁性体
によって形成し、この第１の可動部材５と非接触状態で
配置された磁性体によって形成した第４の可動部材９を
備えた点にある。このような構成において、第４の可動
部材９に、光ファイバ１の軸線方向と直交する方向に被
測定物（図示せず）のひずみ、変位、荷重、圧力、加速
度の物理変化量を与える。第４の可動部材９と第１の可
動部材５との距離が変化することによる磁力変化によっ
て、光ファイバ１に与えられる張力を変化させ、ＦＢＧ
２の伸縮を介してＦＢＧ２からの反射光又は透過光での
波長シフト量として図示を省略した検出手段によって検
出することができる。FIG. 5 is a model diagram showing a fifth embodiment of the present invention. This fifth embodiment is the same as the above-mentioned first embodiment.
The third embodiment is different from the first embodiment in that the first movable member 5 is made of a magnetic material and the fourth movable member 9 is made of a magnetic material that is arranged in a non-contact state with the first movable member 5. There is a point. In such a configuration, the fourth movable member 9 is provided with physical changes in strain, displacement, load, pressure, and acceleration of the object to be measured (not shown) in the direction orthogonal to the axial direction of the optical fiber 1. The tension applied to the optical fiber 1 is changed by the change in the magnetic force caused by the change in the distance between the fourth movable member 9 and the first movable member 5,
The wavelength shift amount of the reflected light or the transmitted light from the FBG 2 via the expansion and contraction of 2 can be detected by a detection means (not shown).
【００４９】なお、これら第１および第４の可動部材
５，９を共に磁性体で形成したが、磁性体の極によって
は、一方を磁性体で形成し他方を導体で形成してもよ
い。また、被測定物から加わる力の方向の角度φを光フ
ァイバ１の軸線方向とほぼ直交する方向にしたが、角度
φが０°以外なら何度でもよい。Although both the first and fourth movable members 5 and 9 are made of magnetic material, one of them may be made of magnetic material and the other may be made of conductor depending on the pole of the magnetic material. Further, although the angle φ of the direction of the force applied from the object to be measured is set to a direction substantially orthogonal to the axial direction of the optical fiber 1, it may be any number as long as the angle φ is other than 0 °.
【００５０】この第５の実施の形態においては、第４の
可動部材９を設けずに、第１の可動部材５に加わる磁力
を変化させる図示を省略した被測定物によって光ファイ
バ１の張力を変化させるようにしてもよい。この場合に
も、ＦＢＧ２の伸縮を介して、ＦＢＧ２からの反射光ま
たは透過光の波長シフト量を図示を省略した検出手段に
よって検出することができる。また、上述したように、
第１の実施の形態においては、わずかな力でもその磁力
変化量を検出できるため、この第５の実施の形態におい
てもより感度の高い磁力変化の検出が可能となる。In the fifth embodiment, the tension of the optical fiber 1 is changed by the object to be measured (not shown) that changes the magnetic force applied to the first movable member 5 without providing the fourth movable member 9. It may be changed. Also in this case, the wavelength shift amount of the reflected light or the transmitted light from the FBG 2 can be detected by the detection means (not shown) through expansion and contraction of the FBG 2. Also, as mentioned above,
In the first embodiment, the amount of change in the magnetic force can be detected even with a slight force, so that the change in the magnetic force can be detected with higher sensitivity in the fifth embodiment.
【００５１】図９は本発明の第５の実施の形態の光ファ
イバセンサを適用した雨量計の構成図である。同図にお
いて、降雨によりある一定量の水が集水口１４から転倒
升１２に溜まると、転倒升１２が左右のいずかに転倒
し、それにともない振り子状に揺動自在に支持された磁
石１３が左右のいずれかに回動する。ＦＢＧ２が書き込
まれた光ファイバ１上を磁石１３が通過すると、光ファ
イバ１に固定された第４の可動部材９が、磁力変化によ
って吸引され、上述した検出原理に基づき、光ファイバ
１に伸縮を与えて、ブラック波長シフトとして検出され
る。図１０は転倒升１２に集められた雨量を検出する出
力グラフである。同図に示すように、約２．５から３秒
の間に転倒升１２が転倒したことがわかる。FIG. 9 is a block diagram of a rain gauge to which the optical fiber sensor according to the fifth embodiment of the present invention is applied. In the figure, when a certain amount of water is collected from the water collecting port 14 in the tipping box 12 due to rainfall, the tipping box 12 falls to either the left or right side, and accordingly, the magnet 13 supported so as to swing like a pendulum. Rotates to either the left or right. When the magnet 13 passes over the optical fiber 1 in which the FBG 2 is written, the fourth movable member 9 fixed to the optical fiber 1 is attracted by the change in magnetic force, and the optical fiber 1 is expanded or contracted based on the detection principle described above. Given, it is detected as a black wavelength shift. FIG. 10 is an output graph for detecting the amount of rainfall collected in the overturned cell 12. As shown in the same figure, it can be seen that the fall box 12 has fallen in about 2.5 to 3 seconds.
【００５２】図６は本発明の第６の実施の形態を示すモ
デル図である。この第６の実施の形態においては、ＦＢ
Ｇ２が書き込まれた光ファイバ１の一端部および他端部
が、それぞれ支持部材１０，１０を介して第１の固定部
材３と第２の固定部材４とに固定されている。これら支
持部材１０，１０は互いに向き合うようにそれぞれ第１
の固定部材３と第２の固定部材４から突出形成されてい
る。これら支持部材１０，１０は、不動部材６の線膨張
係数αよりも高い線膨張係数βを有しており、支持部材
１０，１０の線膨張係数βと、支持部材１０，１０の長
さをあらかじめ調節しておくことにより、光ファイバ１
中のＦＢＧ２からの反射光又は透過光の波長シフト量が
温度によって依存する変化量を補償もしくは低減でき
る。FIG. 6 is a model diagram showing a sixth embodiment of the present invention. In the sixth embodiment, the FB
One end and the other end of the optical fiber 1 in which G2 is written are fixed to the first fixing member 3 and the second fixing member 4 via the supporting members 10 and 10, respectively. These supporting members 10 and 10 are arranged so that they face each other in the first direction.
Of the fixing member 3 and the second fixing member 4. These supporting members 10 and 10 have a linear expansion coefficient β higher than the linear expansion coefficient α of the immovable member 6, and the linear expansion coefficient β of the supporting members 10 and 10 and the length of the supporting members 10 and 10 are equal to each other. By adjusting in advance, the optical fiber 1
It is possible to compensate or reduce the amount of change in the wavelength shift amount of the reflected light or the transmitted light from the FBG 2 depending on the temperature.
【００５３】すなわち、ＦＢＧ２は数式３に示されるよ
うに温度依存性を示しており、その波長−温度係数は上
述したように石英ガラスの線膨張係数よりも大きい。し
たがって、固定部材３，４および不動部材６の線膨張係
数αよりも高い線膨張係数βを有する支持部材１０を設
け、この支持部材１０を介して光ファイバ１を固定し、
温度上昇／下降とともに、支持部材１０，１０間の間隔
を相対的に短尺化／長尺化するよう調節することによ
り、張力緩和によってＦＢＧ２が有する波長の温度増加
分を補償すること、ないしは低減することができる。な
お、支持部材１０，１０は第１の固定部材３と第２の固
定部材４のいずれか一方に設けるようにしてもよい。ま
た、このようなＦＢＧ２自体が有する、温度による波長
変化量を補償する、あるいは低減する技術は、この第６
の実施の形態だけでなく、あらかじめ光ファイバ１に張
力がかけられるもの、すなわち、第１の実施の形態、第
５の実施の形態にも適用できる。That is, the FBG2 exhibits temperature dependence as shown in Expression 3, and its wavelength-temperature coefficient is larger than the linear expansion coefficient of silica glass as described above. Therefore, the support member 10 having a linear expansion coefficient β higher than the linear expansion coefficient α of the fixing members 3 and 4 and the immovable member 6 is provided, and the optical fiber 1 is fixed via the support member 10.
By adjusting the distance between the support members 10 and 10 to be relatively short / long as the temperature rises / falls, the temperature increase of the wavelength of the FBG 2 is compensated or reduced by tension relaxation. be able to. The support members 10 and 10 may be provided on either the first fixing member 3 or the second fixing member 4. Further, the technique of compensating for or reducing the amount of wavelength change due to temperature, which the FBG 2 itself has, is disclosed in the sixth
The present invention can be applied not only to the embodiment described above, but also to those in which tension is applied to the optical fiber 1 in advance, that is, the first embodiment and the fifth embodiment.
【００５４】図７は本発明の第７の実施の形態を示すモ
デル図である。この第７の実施の形態は、上述した第１
の実施の形態において、第１の可動部材５にばね１１の
一端を取り付けた点に特徴を有するものであって、ばね
１１に加わる物理量を間接的に計測する実施例を示して
いる。なお、この第７の実施の形態においては、ばね１
１を例として示しているが、ばね１１は板ばね、あるは
巻ばね等でもよく、またばね以外にもてこや滑車等を用
いて、物理量を変換してもよい。FIG. 7 is a model diagram showing a seventh embodiment of the present invention. The seventh embodiment is the same as the first embodiment described above.
The embodiment is characterized in that one end of the spring 11 is attached to the first movable member 5, and an example of indirectly measuring the physical quantity applied to the spring 11 is shown. In addition, in the seventh embodiment, the spring 1
Although 1 is shown as an example, the spring 11 may be a leaf spring, a coil spring, or the like, and a physical quantity may be converted by using a lever or a pulley other than the spring.
【００５５】ここで、同図においてばねのばね定数をｋ
とすれば、ばねの先端での変位量ｄとの関係は荷重は一
定であるため、数式８を元に数式９で表される。Here, in the figure, the spring constant of the spring is k
If so, the relationship with the displacement amount d at the tip of the spring is expressed by Expression 9 based on Expression 8 because the load is constant.
【００５６】 Fs＝k・（d−s）＝２・Δε・Ａ・E・(2Δε)1/2 …数式９Fs = k · (d−s) = 2 · Δε · A · E · (2Δε) 1/2 (Equation 9)
【００５７】したがって、変位量dは以下の数式１０で
表される。Therefore, the displacement amount d is expressed by the following mathematical expression 10.
【００５８】 d＝(2Δε)1/2・Δε・Ａ・E／k＋s …数式１０D = (2Δε) 1/2 · Δε · A · E / k + s Equation 10
【００５９】したがって、ばね定数ｋを選択することに
よって、検出される荷重Fsあるいは変位量ｄを選択する
ことができ、間接的に物理量を計測することが可能とな
る。Therefore, by selecting the spring constant k, the detected load Fs or displacement amount d can be selected, and the physical quantity can be indirectly measured.
【００６０】[0060]
【発明の効果】本発明によればＦＢＧを有する光ファイ
バを引張った状態で両端を固定部で固定し、光ファイバ
の軸線方向とある角度を有する方向に加わる、ひずみ、
変位、荷重、圧力、加速度、磁力の物理変化量を直接的
または間接的に検出し、より高い感度で物理変化量の検
出が可能になる。また、ＦＢＧが有する波長の温度増加
分を補償すること、ないしは低減することができる。According to the present invention, both ends of the optical fiber having the FBG in a pulled state are fixed by the fixing portions, and strain applied in a direction having an angle with the axial direction of the optical fiber,
The physical change amount of displacement, load, pressure, acceleration, and magnetic force can be detected directly or indirectly, and the physical change amount can be detected with higher sensitivity. Further, it is possible to compensate for or reduce the temperature increase of the wavelength of the FBG.
【図１】 本発明の第１の実施の形態を示すモデル図で
ある。FIG. 1 is a model diagram showing a first embodiment of the present invention.
【図２】 本発明の第２の実施の形態を示すモデル図で
ある。FIG. 2 is a model diagram showing a second embodiment of the present invention.
【図３】 本発明の第３の実施の形態を示すモデル図で
ある。FIG. 3 is a model diagram showing a third embodiment of the present invention.
【図４】 本発明の第４の実施の形態を示すモデルであ
る。FIG. 4 is a model showing a fourth embodiment of the present invention.
【図５】 本発明の第５の実施の形態を示すモデル図で
ある。FIG. 5 is a model diagram showing a fifth embodiment of the present invention.
【図６】 本発明の第６の実施の形態を示すモデル図で
ある。FIG. 6 is a model diagram showing a sixth embodiment of the present invention.
【図７】 本発明の第７の実施の形態を示すモデル図で
ある。FIG. 7 is a model diagram showing a seventh embodiment of the present invention.
【図８】 本発明の第１の実施の形態により得られた出
力図である。FIG. 8 is an output diagram obtained according to the first embodiment of the present invention.
【図９】 本発明の第５の実施の形態を適用した雨量計
の構成図である。FIG. 9 is a configuration diagram of a rain gauge to which a fifth embodiment of the present invention is applied.
【図１０】 本発明の第５の実施の形態を適用した雨量
計により得られた出力図である。FIG. 10 is an output diagram obtained by a rain gauge to which the fifth embodiment of the invention is applied.
１…光ファイバセンサ、２…ＦＢＧ、３…第１の固定部
材、４…第２の固定部材、５…第１の可動部材、６…不
動部材、７…第２の可動部材、８…第３の可動部材、９
…第４の可動部材、１０…支持部材、１１…ばね、１２
…転倒升、１３…磁石、１４…集水口。DESCRIPTION OF SYMBOLS 1 ... Optical fiber sensor, 2 ... FBG, 3 ... 1st fixed member, 4 ... 2nd fixed member, 5 ... 1st movable member, 6 ... Immovable member, 7 ... 2nd movable member, 8 ... 3 movable members, 9
... Fourth movable member, 10 ... Support member, 11 ... Spring, 12
… Overturned box, 13… Magnet, 14… Water collection port.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） // Ｇ０１Ｆ 11/26 Ｇ０１Ｆ 11/26 (72)発明者 菅井 栄一 東京都新宿区西新宿二丁目１番１号 エ ヌ・ティ・ティ・アドバンステクノロジ株 式会社内 (72)発明者 渡部 清昭 東京都品川区南大井６丁目８番２号 株式 会社東京測器研究所内 (72)発明者 山賀 一徳 東京都品川区南大井６丁目８番２号 株式 会社東京測器研究所内 (72)発明者 藤田 清一 神奈川県横浜市西区中央１丁目27番17号 株式会社東亜測器内 Ｆターム(参考） 2F065 AA65 FF49 LL02 LL41 2F103 BA01 BA10 BA37 CA09 EC09 GA15 2G017 AB05 AC09 AD11 BA09 ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 7 Identification code FI theme code (reference) // G01F 11/26 G01F 11/26 (72) Inventor Eiichi Sugai 2-chome, Nishishinjuku, Shinjuku-ku, Tokyo No. 1 NTT Advanced Technology Co., Ltd. (72) Inventor Kiyoaki Watanabe 6-8 Minamioi, Shinagawa-ku, Tokyo Tokyo Sokki Kenkyusho (72) Inventor Kazunori Yamaga Tokyo 6-8-2 Minamiooi, Shinagawa-ku, Tokyo Metropolitan Institute of Instrument Research (72) Inventor Seiichi Fujita 1-27-17 Chuo, Nishi-ku, Yokohama-shi, Kanagawa Toa Sokki F-term (reference) 2F065 AA65 FF49 LL02 LL41 2F103 BA01 BA10 BA37 CA09 EC09 GA15 2G017 AB05 AC09 AD11 BA09
Claims (9)
光ファイバと、この光ファイバの両端部を固定する第１
の固定部材および第２の固定部材と、これら第１および
第２の固定部材を固定する不動部材と、前記光ファイバ
の前記ファイバグレーティングを含まない両端部間に光
ファイバを介在した第１の可動部材と、この第１の可動
部材に光ファイバの軸線方向とある角度を有する方向に
物理変化量を与える被測定物とにおいて、この被測定物
から与えられる物理変化量を光ファイバの張力変化量に
変換し、前記ファイバグレーティングの伸縮を介して、
ファイバグレーティングからの反射光または透過光の波
長シフト量として検出する検出手段とを備えたことを特
徴とする光ファイバセンサ。1. An optical fiber in which a fiber grating is written, and a first end for fixing both ends of the optical fiber.
Fixing member and a second fixing member, an immovable member fixing the first and second fixing members, and a first movable member having an optical fiber interposed between both ends of the optical fiber not including the fiber grating. In the member and the DUT that gives the first movable member a physical change amount in a direction having an angle with the axial direction of the optical fiber, the physical change amount given from the DUT is the tension change amount of the optical fiber. , Through the expansion and contraction of the fiber grating,
An optical fiber sensor comprising: a detection unit that detects a wavelength shift amount of reflected light or transmitted light from a fiber grating.
て、自重でたるませた状態で光ファイバを前記第１の固
定部材と前記第２の固定部材との間に固定したことを特
徴とする光ファイバセンサ。2. The optical fiber sensor according to claim 1, wherein the optical fiber is fixed between the first fixing member and the second fixing member while being slackened by its own weight. Fiber sensor.
て、予め張力を加えた状態で光ファイバを前記第１の固
定部材と前記第２の固定部材との間に固定したことを特
徴とする光ファイバセンサ。3. The optical fiber sensor according to claim 1, wherein the optical fiber is fixed between the first fixing member and the second fixing member while tension is applied in advance. Fiber sensor.
光ファイバと、この光ファイバの一端部を固定する第１
の固定部材と、光ファイバの他端部を磁性体で固定した
第２の可動部材と、この第２の可動部材に磁力変化を与
える被測定物とにおいて、この被測定物から与えられる
磁力変化量を光ファイバの張力変化量に変換し、前記フ
ァイバグレーティングの伸縮を介して、ファイバグレー
ティングからの反射光または透過光の波長シフト量とし
て検出する検出手段とを備えたことを特徴とする光ファ
イバセンサ。4. An optical fiber in which a fiber grating is written, and a first part for fixing one end of this optical fiber.
Of the fixed member, the second movable member in which the other end of the optical fiber is fixed with a magnetic substance, and the object to be measured that changes the magnetic force to the second movable member, the change in magnetic force applied from the object to be measured. An optical fiber, which is provided with a detecting means for converting the amount into a tension change amount of the optical fiber and detecting the wavelength shift amount of the reflected light or the transmitted light from the fiber grating through expansion and contraction of the fiber grating. Sensor.
て、前記第２の可動部材と非接触状態で配置された第３
の可動部材と、この第３の可動部材に物理変化量を与え
る被測定物とにおいて、これら第２および第３の可動部
材を共に磁性体で形成するか、または一方を磁性体で形
成し他方を導体で形成し、前記第３の可動部材に与えら
れる物理変化量を、前記第２の可動部材に与えられる磁
力変化量に変えて、前記被測定物から与えられる物理変
化量を光ファイバの張力変化量に変換し、前記ファイバ
グレーティングの伸縮を介して、ファイバグレーティン
グからの反射光又は透過光の波長シフト量として検出す
る検出手段とを備えたことを特徴とする光ファイバセン
サ。5. The optical fiber sensor according to claim 4, wherein the third movable member is arranged in a non-contact state with the second movable member.
Of the movable member and the object to be measured which gives a physical change amount to the third movable member, both of the second and third movable members are made of a magnetic material, or one of them is made of a magnetic material and the other is made of a magnetic material. Is formed of a conductor, and the amount of physical change given to the third movable member is changed to the amount of change of magnetic force given to the second movable member, so that the amount of physical change given from the object to be measured is changed to that of the optical fiber. An optical fiber sensor comprising: a change amount of tension, and a detection unit that detects the amount of wavelength shift of reflected light or transmitted light from the fiber grating through expansion and contraction of the fiber grating.
て、前記第１の可動部材を磁性体で形成し、この第１の
可動部材に磁力変化を与える被測定部とにおいて、この
被測定物から与えられる磁力変化量を光ファイバの張力
変化量に変換し、前記ファイバグレーティングの伸縮を
介して、ファイバグレーティングからの反射光又は透過
光の波長シフト量として検出する検出手段とを備えたこ
とを特徴とする光ファイバセンサ。6. The optical fiber sensor according to claim 1, wherein the first movable member is made of a magnetic material, and the measured portion that gives a magnetic force change to the first movable member is separated from the measured object. And a detection means for converting the applied magnetic force change amount into an optical fiber tension change amount and detecting the amount of wavelength shift of reflected light or transmitted light from the fiber grating through expansion and contraction of the fiber grating. And an optical fiber sensor.
て、前記第１の可動部材と非接触状態で配置された第４
の可動部材と、光ファイバの前記第１の可動部材に光フ
ァイバの軸線方向とある角度を有する方向に物理変化量
を与える被測定物とにおいて、これら第１および第４の
可動部材を共に磁性体で形成するか、または一方を磁性
体で形成し他方を導体で形成し、前記第４の可動部材に
与えられる物理変化量を、前記第１の可動部材に与えら
れる磁力変化量に変えて、前記被測定物から与えられる
物理変化量を光ファイバの張力変化量に変換し、前記フ
ァイバグレーティングの伸縮を介して、ファイバグレー
ティングからの反射光又は透過光の波長シフト量として
検出する検出手段とを備えたことを特徴とする光ファイ
バセンサ。7. The optical fiber sensor according to claim 6, wherein the fourth movable member is arranged in a non-contact state with the first movable member.
And the object to be measured which gives the first movable member of the optical fiber a physical change amount in a direction having an angle with the axial direction of the optical fiber, both of the first and fourth movable members are magnetic. Or by forming one of them with a magnetic substance and the other with a conductor, and changing the physical change amount given to the fourth movable member into the magnetic force change amount given to the first movable member. A detecting means for converting a physical change amount given from the object to be measured into a tension change amount of an optical fiber, and detecting as a wavelength shift amount of reflected light or transmitted light from the fiber grating through expansion and contraction of the fiber grating; An optical fiber sensor comprising:
センサにおいて、前記第１の固定部材と、第２の固定部
材と、前記第１の固定部材と第２の固定部材を固定する
不動部材と、前記第１の固定部材と第２の固定部材のう
ちの少なくともいずれか一方と光ファイバとの間に介在
させる支持部材とを備え、前記固定部材および前記支持
部材の線膨張係数を前記不動部材の線膨張係数よりも大
きく設定し、かつ支持部材の光ファイバの軸線方向の長
さを調節し、光ファイバ中のファイバグレーティングか
らの反射光又は透過光の波長シフト量が温度によって依
存する変化量を補償もしくは低減したことを特徴とする
光ファイバセンサ。8. The optical fiber sensor according to claim 1, 3, 6, or 7, wherein the first fixing member, the second fixing member, and the first fixing member and the second fixing member are fixed. And a supporting member interposed between at least one of the first fixing member and the second fixing member and the optical fiber, and the linear expansion coefficient of the fixing member and the supporting member. Is set to be larger than the linear expansion coefficient of the immovable member, and the length of the supporting member in the axial direction of the optical fiber is adjusted, and the wavelength shift amount of the reflected light or the transmitted light from the fiber grating in the optical fiber depends on the temperature. An optical fiber sensor characterized by compensating or reducing a dependent change amount.
サにおいて、前記可動部材と被測定物の間に、付勢手段
又は／及びてこ又は／及び滑車を介在させるとともに、
付勢手段の付勢力又は／及びてこ比を調整自在としたこ
とを特徴とする光ファイバセンサ。9. The optical fiber sensor according to claim 1, wherein an urging means or / and a lever or / and a pulley is interposed between the movable member and the object to be measured,
An optical fiber sensor, wherein the urging force or / and the leverage of the urging means can be adjusted.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002015384A JP2003214907A (en) | 2002-01-24 | 2002-01-24 | Optical fiber sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002015384A JP2003214907A (en) | 2002-01-24 | 2002-01-24 | Optical fiber sensor |
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| Publication Number | Publication Date |
|---|---|
| JP2003214907A true JP2003214907A (en) | 2003-07-30 |
Family
ID=27651796
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
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| JP2008541122A (en) * | 2005-05-17 | 2008-11-20 | ペトロレオ ブラジレイロ ソシエダ アノニマ − ペトロブラス | Optical fiber position transducer with magnetostrictive material and position calibration method |
| JP2009503449A (en) * | 2005-07-22 | 2009-01-29 | エクソンモービル リサーチ アンド エンジニアリング カンパニー | Optical fiber strain adjustment type material change sensor |
| CN101750590A (en) * | 2009-10-16 | 2010-06-23 | 电子科技大学 | Method and device for measuring environment temperature change and magnetic induction strength |
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