JPH01277000A - Acoustic sensor - Google Patents
Acoustic sensorInfo
- Publication number
- JPH01277000A JPH01277000A JP10634988A JP10634988A JPH01277000A JP H01277000 A JPH01277000 A JP H01277000A JP 10634988 A JP10634988 A JP 10634988A JP 10634988 A JP10634988 A JP 10634988A JP H01277000 A JPH01277000 A JP H01277000A
- Authority
- JP
- Japan
- Prior art keywords
- optical fiber
- acoustic sensor
- films
- sound
- fabry
- 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.)
- Pending
Links
- 239000013307 optical fiber Substances 0.000 claims abstract description 30
- 239000004065 semiconductor Substances 0.000 claims abstract description 7
- 239000011521 glass Substances 0.000 claims abstract description 5
- 239000012528 membrane Substances 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 3
- 229920003023 plastic Polymers 0.000 claims description 2
- 230000003287 optical effect Effects 0.000 abstract description 10
- 238000006073 displacement reaction Methods 0.000 abstract description 8
- 238000004519 manufacturing process Methods 0.000 abstract description 7
- 230000035945 sensitivity Effects 0.000 abstract description 7
- 230000005540 biological transmission Effects 0.000 description 9
- 238000010586 diagram Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000002985 plastic film Substances 0.000 description 1
Landscapes
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
- Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、光学現象を利用して音響信号を光の強度変化
に変換して検出する光学式の音響センサに関する。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical acoustic sensor that converts an acoustic signal into a change in light intensity and detects the change using an optical phenomenon.
従来の技術
近年、半導体レーザや光ファイバが実用期に入ったこと
により、光学現象を利用した種々の音響センサが開発さ
れつつある。2. Description of the Related Art In recent years, as semiconductor lasers and optical fibers have come into practical use, various acoustic sensors that utilize optical phenomena are being developed.
以下、図面を参照しながら、上述したような従来の音響
センサについて説明する。Hereinafter, the conventional acoustic sensor as described above will be explained with reference to the drawings.
第２図は従来の音響センサの概念図を示すものである。FIG. 2 shows a conceptual diagram of a conventional acoustic sensor.
第２図において、１は半導体レーザモジュール、２はフ
ォトダイオードモジュール、３はシングルモード光ファ
イバ、４はマルチモード光ファイバ、５．６は光ファイ
バコリメータ、７は受音振動膜、８はセンサヘッドホル
ダーで、９゜９′は光ファイバコリメータ５の端面と受
音振動膜７の相対する側に設けた部分光反射透過膜であ
る。In Fig. 2, 1 is a semiconductor laser module, 2 is a photodiode module, 3 is a single mode optical fiber, 4 is a multimode optical fiber, 5.6 is an optical fiber collimator, 7 is a sound receiving diaphragm, and 8 is a sensor head. In the holder, 9° 9' is a partial light reflection/transmission film provided on the opposite side of the end face of the optical fiber collimator 5 and the sound receiving vibration film 7.
以上のように構成された従来の音響センサについて以下
その動作について説明する。The operation of the conventional acoustic sensor configured as described above will be described below.
半導体レーザモジュール１から出射したレーザ光は、シ
ングルモード光ファイバ３を通って光ファイバコリメー
タ５から平行ビーム光となって出射する。この出射光は
上記光ファイバコリメータ５と、これに相対した受音振
動膜７の両者の内側に設けた部分光反射透過ｎ’Ｊ９，
９’の間で、繰り返し反射を起こし、いわゆるファブリ
・ペロー干渉を生じて後、その透過光は光ファイバコリ
メータ６に結合して、マルチモード光ファイバ４を通っ
てフォトダイオードモジュール２で電気変換される。セ
ンサヘッドホルダー８内の受音振動膜７が音響信号で振
動すると、透過光はファブリ・ペロー干渉によって振動
膜の変位に応じて光強度変化に変換され、フォトダイオ
ードモジュール２で検出される。Laser light emitted from the semiconductor laser module 1 passes through the single mode optical fiber 3 and is emitted from the optical fiber collimator 5 as a parallel beam of light. This emitted light is transmitted through a partial light reflection transmission n'J9 provided inside both the optical fiber collimator 5 and the sound receiving vibration membrane 7 opposite thereto.
9', the transmitted light is repeatedly reflected and causes so-called Fabry-Perot interference, and then is coupled to an optical fiber collimator 6, passes through a multimode optical fiber 4, and is electrically converted by a photodiode module 2. Ru. When the sound-receiving diaphragm 7 in the sensor head holder 8 vibrates with an acoustic signal, the transmitted light is converted into a light intensity change according to the displacement of the diaphragm due to Fabry-Perot interference, and is detected by the photodiode module 2.
発明が解決しようとする課題
しかしながら、上記の構成では、振動膜が一枚のために
感度が低く、さらに微妙な調整を必要とする光ファイバ
コリメータの端面に部分光反射透過膜をコートするとい
う問題点を有していた。Problems to be Solved by the Invention However, with the above configuration, the sensitivity is low due to the single vibrating membrane, and there is also the problem of coating the end face of the optical fiber collimator with a partial light reflection/transmission film, which requires delicate adjustment. It had a point.
本発明は上記問題点に鑑み、従来より大きな感度を持ち
、部分光反射透過膜のコートが受音振動膜面のみですむ
、信頼性の高い光学式の音響センサを提供するものであ
る。In view of the above-mentioned problems, the present invention provides a highly reliable optical acoustic sensor that has greater sensitivity than the conventional sensor and requires only the sound-receiving diaphragm surface to be coated with a partial light reflection-transmission film.
課題を解決するための手段
上記問題点を解決するために本発明の音響センサは、光
ファイバコリメータ間に部分光反射透過をしてファブリ
・ペロー干渉を生じる二枚の受音振動膜を設けるという
構成を備えたものである。Means for Solving the Problems In order to solve the above problems, the acoustic sensor of the present invention is provided with two sound-receiving diaphragms between optical fiber collimators that partially reflect and transmit light to cause Fabry-Perot interference. It has a configuration.
作用
本発明は上記した構成によって二倍の振動変位と、さら
に二倍のファブリ・ペロー干渉強度変調により、従来よ
り４倍も感度が高（なり、かつ部分光反射透過膜を受音
振動膜面のみにすることによって、製造しやすく、信頼
性も高くなる。Function The present invention has the above-mentioned structure, which doubles the vibration displacement and further doubles the Fabry-Perot interference intensity modulation, resulting in four times higher sensitivity than the conventional one (and the partial light reflection/transmission film is placed on the sound-receiving vibration film surface). By using only a single device, manufacturing becomes easier and reliability becomes higher.
実施例
以下、本発明の一実施例の音響センサについて、図面を
参照しながら説明する。EXAMPLE Hereinafter, an acoustic sensor according to an example of the present invention will be described with reference to the drawings.
第１図は本発明の実施例における音響センサの概念図を
示すものである。第１図に於て、６．６′は光ファイバ
コリメータ、１１．１１’ は間隙を設けて平行に配置
した透明なプラスチックフィルム、ガラスフィルム様の
受音振動膜、１２．１２’は受音振動膜面内側にコート
した部分光反射透過膜、１３はセンサヘンドホルダーで
ある０以上のように構成された音響センサについて、第
１図を用いてその動作を説明する。FIG. 1 shows a conceptual diagram of an acoustic sensor in an embodiment of the present invention. In Figure 1, 6.6' is an optical fiber collimator, 11.11' is a transparent plastic film arranged in parallel with a gap, a glass film-like sound receiving vibration membrane, and 12.12' is a sound receiving device. The operation of an acoustic sensor configured as shown in FIG. 1 will be described with reference to FIG.
第１図において、半導体レーザモジュール１から出射し
た波長１．３μレーザ光は、シングルモー・ド光ファイ
バ３を通って光ファイバコリメータ１０から平行ビーム
光となって出射する。この出射光は極めて平行に約３０
０μの一定の間隙を持って相対して配置した、二枚の５
０μ厚の透明なガラスフィルムからなる受音振動膜１１
．１１’を通過する。この時、両者の受音振動膜の内側
に設けた約４０％の光反射率を持つ誘電体多Ｎ膜からな
る部分光反射透過膜１２．１２’の間で、繰り返し反射
を起こし、いわゆるファブリ・ペロー干渉を生じて後、
その透過光は光ファイバコリメータ１０′に結合して、
マルチモード光ファイバ４を通ってフォトダイオードモ
ジュール２で電気変換される。センサヘッドホルダー１
３内の二枚の受音振動膜１１．１１’が音響信号で振動
すると、透過光はファブリ・ペロー干渉によって振動膜
の変位に応じて光強度変化に変換され、フォトダイオー
ドモジュール２で検出される。振動変位は二枚の振動膜
の変位が加算されて２倍となる。In FIG. 1, a laser beam with a wavelength of 1.3 μm emitted from a semiconductor laser module 1 passes through a single mode optical fiber 3 and is emitted from an optical fiber collimator 10 as a parallel beam. This emitted light is extremely parallel to about 30
Two 5 pieces placed opposite each other with a constant gap of 0 μ.
Sound receiving vibration membrane 11 made of a transparent glass film with a thickness of 0μ
．． 11'. At this time, repeated reflections occur between the partial light reflection and transmission films 12 and 12' made of a dielectric multi-N film with a light reflectance of about 40% provided inside the sound receiving diaphragms of the two, and so-called fabrication.・After Perot interference occurs,
The transmitted light is coupled to an optical fiber collimator 10',
It passes through a multimode optical fiber 4 and is converted into electricity by a photodiode module 2. Sensor head holder 1
When the two sound-receiving diaphragms 11 and 11' in 3 vibrate with an acoustic signal, the transmitted light is converted into a light intensity change according to the displacement of the diaphragm due to Fabry-Perot interference, and is detected by the photodiode module 2. Ru. The vibration displacement is doubled by adding the displacements of the two vibrating membranes.
さらにファブリ・ペロー干渉による変調強度も２倍とな
って、合計４倍の感度が従来の音響センサより得られる
。また、製造上、微妙な光学的調整を必要とする光ファ
イバコリメータの端面に部分光反射透過膜をコートする
ことなく、二枚の受音振動膜面に同時にコートできるた
め、製造し安い、信頼性の高い音響センサとなる。Furthermore, the modulation intensity due to Fabry-Perot interference is also doubled, resulting in a total sensitivity four times greater than that of conventional acoustic sensors. In addition, since it is possible to coat two sound-receiving diaphragms at the same time without coating the end face of an optical fiber collimator with a partial light reflection/transmission film, which requires delicate optical adjustment during manufacturing, it is inexpensive and reliable to manufacture. It becomes a highly sensitive acoustic sensor.
以上のように、光ファイバコリメータ間に部分光反射透
過をする二枚の受音振動膜を設けたことにより、感度の
大きい、製造し安い、信頼性の高い光学式の音響センサ
とすることができる。As described above, by providing two sound-receiving vibration membranes that partially reflect and transmit light between the optical fiber collimators, it is possible to create an optical acoustic sensor that is highly sensitive, inexpensive to manufacture, and highly reliable. can.
なお、実施例において二枚の受音振動膜の間隙は３００
μとしたが、ファブリ・ペロー干渉を起こし、かつ振動
膜が自由に振動できる間隙であればよく、数μから１１
００ｎ＋の間隙でもよい。In addition, in the example, the gap between the two sound-receiving diaphragms is 300
μ, but any gap that causes Fabry-Perot interference and allows the diaphragm to vibrate freely is sufficient, ranging from several μ to 11
A gap of 00n+ may be used.
また、受音振動膜の材質はガラスしとだが、透明なプラ
スチック様のものでもよい。さらに、その厚みは５０μ
に限定せず音響的に決められる。Furthermore, although the material of the sound-receiving diaphragm is glass, it may be made of a transparent plastic-like material. Furthermore, its thickness is 50μ
It can be determined acoustically without being limited to.
また、受音振動膜の光反射率は４０％としたが、ファブ
リ・ペロー干渉を起こす条件の光反射であればよい。Further, although the light reflectance of the sound receiving diaphragm was set to 40%, it may be any light reflection condition that causes Fabry-Perot interference.
さらに、半導体レーザモジュール１からの出射光をシン
グルモード光ファイバによって、また部分光反射透過膜
１２′の透過光をマルチモード光ファイバによってそれ
ぞれ伝送したが、光伝送には光ファイバを用いればよい
のであって、モードを限定する・ものではない。Furthermore, although the emitted light from the semiconductor laser module 1 was transmitted through a single mode optical fiber and the transmitted light through the partial light reflection/transmission film 12' was transmitted through a multimode optical fiber, it is possible to use an optical fiber for optical transmission. However, it does not limit the mode.
発明の効果
以上のように本発明は二つの光ファイバコリメータ間に
、部分光反射透過をしてファブリ・ペロー干渉を生じ、
間隙を設けて配置した二枚の受音振動膜をもうけること
により、感度の大きい、製造し安い、信頼性の高い光学
式の音響センサとすることができる。Effects of the Invention As described above, the present invention allows partial light to be reflected and transmitted between two optical fiber collimators, causing Fabry-Perot interference.
By providing two sound-receiving diaphragms arranged with a gap between them, an optical acoustic sensor with high sensitivity, low manufacturing cost, and high reliability can be obtained.
第１図は本発明の実施例における音響センサの概念図、
第２図は従来の音響センサの概念図である。
１０．１０’ ・・・・・・光ファイバコリメータ、１
１゜１１’・・・・・・受音振動膜、１２．１２’・・
・・・・部分光反射透過膜、１３・・・・・・センサヘ
ッドホルダー。FIG. 1 is a conceptual diagram of an acoustic sensor in an embodiment of the present invention,
FIG. 2 is a conceptual diagram of a conventional acoustic sensor. 10.10'...Optical fiber collimator, 1
1゜11'...Sound receiving vibration membrane, 12.12'...
...Partial light reflection and transmission film, 13...Sensor head holder.
Claims (2)
の先端にある一方の光ファイバコリメータと、フォトダ
イオードモジュールに結合された光ファイバの先端にあ
る他方の光ファイバコリメータとが光学的に結合してい
て、上記の二つの光ファイバコリメータ間に部分光反射
透過をしてファブリ・ペロー干渉を生じ、間隙を設けて
配置した二枚の受音振動膜を設けてなる音響センサ。(1) One optical fiber collimator at the tip of the optical fiber coupled to the semiconductor laser module and the other optical fiber collimator at the tip of the optical fiber coupled to the photodiode module are optically coupled. , an acoustic sensor comprising two sound-receiving diaphragms arranged with a gap between the two optical fiber collimators to partially reflect and transmit light to produce Fabry-Perot interference.
クフィルム様の材料からなる請求項（１）記載の音響セ
ンサ。(2) The acoustic sensor according to claim 1, wherein the sound-receiving vibration membrane is made of a transparent glass film or plastic film-like material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10634988A JPH01277000A (en) | 1988-04-28 | 1988-04-28 | Acoustic sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10634988A JPH01277000A (en) | 1988-04-28 | 1988-04-28 | Acoustic sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01277000A true JPH01277000A (en) | 1989-11-07 |
Family
ID=14431318
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10634988A Pending JPH01277000A (en) | 1988-04-28 | 1988-04-28 | Acoustic sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01277000A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104697624A (en) * | 2015-03-18 | 2015-06-10 | 华中科技大学 | Acoustic detector based on Michelson interferometer |
| NO20151276A1 (en) * | 2015-09-29 | 2017-03-30 | Sintef Tto As | Noise canceling detector |
| CN117007173A (en) * | 2023-10-07 | 2023-11-07 | 山东省科学院激光研究所 | Optical fiber acoustic wave sensor for monitoring pipeline leakage |
-
1988
- 1988-04-28 JP JP10634988A patent/JPH01277000A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104697624A (en) * | 2015-03-18 | 2015-06-10 | 华中科技大学 | Acoustic detector based on Michelson interferometer |
| CN104697624B (en) * | 2015-03-18 | 2017-07-07 | 华中科技大学 | A kind of acoustic detector based on Michelson's interferometer |
| NO20151276A1 (en) * | 2015-09-29 | 2017-03-30 | Sintef Tto As | Noise canceling detector |
| CN108139319A (en) * | 2015-09-29 | 2018-06-08 | 辛特福特图有限公司 | Eliminate noise-type detector |
| NO344002B1 (en) * | 2015-09-29 | 2019-08-12 | Sintef Tto As | Optical gas detector |
| US10768096B2 (en) | 2015-09-29 | 2020-09-08 | Sintef Tto As | Noise canceling detector |
| EP3356797B1 (en) * | 2015-09-29 | 2021-08-04 | Sintef TTO AS | Noise cancelling detector |
| CN117007173A (en) * | 2023-10-07 | 2023-11-07 | 山东省科学院激光研究所 | Optical fiber acoustic wave sensor for monitoring pipeline leakage |
| CN117007173B (en) * | 2023-10-07 | 2024-01-30 | 山东省科学院激光研究所 | Optical fiber acoustic wave sensor for monitoring pipeline leakage |
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