EP2095084A2 - Capteur de pression optique avec au moins deux fibres optiques - Google Patents

Capteur de pression optique avec au moins deux fibres optiques

Info

Publication number
EP2095084A2
EP2095084A2 EP07816272A EP07816272A EP2095084A2 EP 2095084 A2 EP2095084 A2 EP 2095084A2 EP 07816272 A EP07816272 A EP 07816272A EP 07816272 A EP07816272 A EP 07816272A EP 2095084 A2 EP2095084 A2 EP 2095084A2
Authority
EP
European Patent Office
Prior art keywords
fiber
light
sensor according
membrane
fibers
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.)
Withdrawn
Application number
EP07816272A
Other languages
German (de)
English (en)
Inventor
Adrian Kummer
Marco Gnielka
Axel Bertholds
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kistler Holding AG
Original Assignee
Kistler Holding AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kistler Holding AG filed Critical Kistler Holding AG
Publication of EP2095084A2 publication Critical patent/EP2095084A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
    • G01L9/0041—Transmitting or indicating the displacement of flexible diaphragms
    • G01L9/0076—Transmitting or indicating the displacement of flexible diaphragms using photoelectric means
    • G01L9/0077—Transmitting or indicating the displacement of flexible diaphragms using photoelectric means for measuring reflected light
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/264—Optical coupling means with optical elements between opposed fibre ends which perform a function other than beam splitting

Definitions

  • the invention relates to an optical pressure sensor based on light intensity measurements, comprising at least one membrane and at least one first optical fiber and a light exit surface, and at least one second optical fiber arranged parallel to the first optical fiber, and a light entry surface, wherein a light beam from the first fiber can be passed over the light exit surface to the membrane and reflected at this, and wherein the reflected light beam can penetrate via the light entry surface in the second fiber and can be transported in this further.
  • Optical sensors of this type are used for example for engine pressure measurements and installed for this purpose, for example in standard spark plugs.
  • Other models are used, for example, in miniaturized nozzle pressure sensors.
  • light is emitted from a first fiber to a membrane.
  • This membrane is at a different position, ie nearer or farther away from the emitting fiber, depending on what pressure is applied to it from the other side.
  • the light is now reflected on the membrane.
  • Part of the reflected light impinges on the second fiber, which forwards the light to a meter in which this light intensity of the light is measured. Based on the measured light intensity can finally be closed to the position of the membrane with respect to the optical fibers and thus to the prevailing at this time of measurement pressure on the membrane.
  • a disadvantage of such systems is that a small signal is superimposed on a huge offset. Smallest disturbances of this offset therefore result in massive errors in the measured pressure signal.
  • Object of the present invention is to provide an optical pressure sensor of the type described above, which is less sensitive to load change drift, thermal shock and drift.
  • the idea underlying the invention is that the light exit surface and the light entry surface of the two fibers are arranged facing away from each other.
  • the radiation path of the light is changed in such a way that, in use, the proportion of light received by the receiving fiber 4 depends strongly on the position of the membrane.
  • the membrane can be arranged close to the fiber ends, so that a greater proportion of the light intensity can be used. This increases the dynamics of interference.
  • the variance of the light intensity is linear to the applied pressure.
  • the simplest way to achieve the invention is by a roof grinding of a ferrule which contains these two fibers, wherein the light exit surface and the light entry surface are arranged on a respective roof side of the cut.
  • 1a is a schematic representation in section of an optical sensor in the region of the sensor head according to the prior art
  • FIG. 1b shows a perspective schematic illustration of a prior art optical sensor in the region of the fiber ends of the light guides
  • FIG. 2 a shows a schematic illustration in the section of an optical sensor according to the invention in the region of FIG
  • FIG. 2b shows a perspective schematic illustration of an optical sensor according to the invention in the region of the fiber ends of the light guides
  • Fig. 3 is a schematic representation in section of a fiber
  • FIG. 4 shows a perspective view of an alternative embodiment of a sensor according to the invention in the region of the fiber ends; 5 shows a plan view of an alternative embodiment of a sensor according to the invention in the region of the fiber ends with a multiplicity of fibers;
  • FIGS. 6a-d are perspective views of alternative embodiments of differently shaped light exit and light entry surfaces
  • FIG. 7 is a schematic representation in section of an alternative embodiment of an optical sensor according to the invention in the region of the sensor head;
  • FIG. 8 shows a schematic time-dependent sensor signal using a) a sensor according to the prior art and b) a sensor according to the invention.
  • FIG. 1a shows a schematic representation in section of an optical sensor in the region of the sensor head according to the prior art.
  • a ferrule 11 a first photoconductive fiber 1 with its fiber end 2 and a first fiber 1 arranged parallel to the second photoconductive fiber 4 are shown with a fiber end 5.
  • light 10 is emitted by the first fiber 1 at a light exit surface 3 in the direction of a membrane 8 and reflected at this.
  • a part of this light beam 10 finally enters a light entry surface 6 of the second fiber 4 and is forwarded to evaluate the light intensity.
  • the membrane 8 and the ferrule 11 with the two light-conducting fibers 1, 4 are held by a housing 9 in a given position.
  • the membrane 8 moves closer to the fiber ends 2, 5 of the fibers 1, 4. This changes the proportion of originally emitted by the first fiber 1 light 10, which is inserted into the second fiber 4 a occurs. On the basis of the forwarded by the second fiber 4 light intensity can be concluded that the currently prevailing pressure, since the irradiated by the first fiber 1 light intensity is known.
  • FIG. 1b shows the end of the ferrule 11 with the two fiber ends 2, 5, the light exit surface 3 of the first fiber 1 and the light entry surface 6 of the second fiber 4 in a perspective illustration according to the prior art.
  • the end of the ferrule is ground flat as a whole, so that the light exit surface 3 and the light entry surface 6 are both in a plane that runs parallel to the membrane 8.
  • Fig. 2a the same arrangement as shown in Fig. Ia is shown, with the difference that the light entrance surface 3 and the light exit surface 6 are arranged facing away from each other. They are not, as in FIG. 1 a, on a plane that runs parallel to the membrane, but are inclined at an angle ⁇ to it.
  • the emerging light beam 10 is refracted at the light exit surface 3 of the fiber 1 against the center of the ferrule 11 and reflected on the membrane 8 in the direction of the light entry surface 6. Since the entry angle is favorable, a light beam 10 reaching the light entry surface 6 is transmitted in the second fiber 4. But it is crucial that the amount of light of the incoming light beam 10 depends strongly on the membrane position and changes in proportion to this.
  • the useful signal is amplified in comparison to the offset and the quality of the measurement is increased.
  • the distance of the membrane 8 to the fiber ends 2, 5 and the angle ⁇ are optimized according to various aspects.
  • the refractive indices on both sides of the light exit surface 3 and of the light entry surface 6 define the angle of the total reflection which sets a limit to the entry and exit angles.
  • the difference caused by the different membrane positions of the light occurring at the light entry surface 6 should have the highest possible dynamics. This means that the intensity of the light 10 arriving in the second fiber 4 varies as much as possible by changing the position of the membrane 8.
  • FIG. 2b shows the end of the ferrule 11 with the two fiber ends 2, 5, the light exit surface 3 of the first fiber 1 and the light entry surface 6 of the second fiber 4 in a perspective view in an embodiment according to the invention.
  • the end of the ferrule 11 is ground in this embodiment in a roof joint, each of the fiber ends 2, 5 ends on a different roof surface.
  • the fiber ends 2, 5 are arranged symmetrically with respect to a median plane 14 of the sensor.
  • the ridge of the roof Schliffs forms this central plane 14.
  • a further preferred embodiment consists in that the light exit surface 3 and the light entry surface 6 in two levels 12, 13 are located. These planes 12, 13 describe in Fig. 2b, the two roof surfaces of the roof cut.
  • the angle ⁇ between the surfaces of the roof cut and a plane parallel to the membrane 8 should be as steep as possible, but without total reflection occurring at the light exit surface 3 or the light entry surface 6. Angles between 20 and 40 °, in particular between 25 and 35 ° have proven to be particularly suitable.
  • FIG. 8 shows schematically a time-dependent sensor signal, in the first region 18 without load and in the second region 19 with full load, wherein in a) a sensor according to the prior art according to FIG. 1 and in b) a sensor according to the invention, for example according to FIG has been used.
  • the first area 18 shows an offset signal 20, the second area 19 a useful signal 21, which is superimposed on the offset signal 20.
  • the ratio of useful signal to offset signal in the arrangement according to the invention compared to the arrangement of the prior art could be improved by a multiple.
  • the sensor according to the invention is greatly improved with regard to load change drift, thermal shock and drift.
  • Fig. 3 illustrates a light-conducting fiber in cross-section.
  • the fiber consists of a light-conducting core 15 which is surrounded by a jacket 16. This jacket 16 is in turn surrounded by a protective layer 17.
  • a fiber should be used whose core 15 constitutes at least 40% of the total area or 60% of the total diameter of the fiber.
  • the fibers 1, 4 are guided in parallel, which simplifies their handling and processing and allows the miniaturization of the sensor.
  • the fibers 1, 4 are guided in a ferrule 11, which , however, is not absolutely necessary for carrying out the invention.
  • the symmetrical arrangement of the light exit surface 3 and the light entry surface 6 in the sensor is not absolutely necessary, but facilitates the assembly and the evaluation.
  • Fig. 4 An alternative to Fig. 2b embodiment is shown in Fig. 4.
  • the ferrule 11 has a conical tip, similar to a sharpened pencil with two adjacent mines as fibers 1, 4.
  • FIG. 5 A further alternative embodiment is shown in Fig. 5 as a plan view of a ferrule 11 with fiber ends 2, 5.
  • first and second fibers 1, 4 are shown, wherein in operation the first fibers 1 are the transmitting and the second fibers 4 are the receiving fibers.
  • These fibers 1, 4 are arranged on both sides of the median plane 14.
  • All advantageous embodiments, described for Fig. 2 apply analogously to this arrangement with a plurality of first and second fibers 1, 4.
  • all the light exit surfaces 3 and all light entry surfaces 6 may each be arranged in planes, preferably all the light exit surfaces 3 in a first plane 12th and all the light entry surfaces 6 lie in a second plane 13.
  • These first and second fibers 4 can each be in a row as shown on both sides and close to the Center plane 14, preferably touching each other, be arranged. They can also be arranged in several rows or randomly on both sides of the center line.
  • Fig. 6 indicates further embodiments, in perspective view.
  • the figures describe various cut shapes, each of which, as shown, only one fiber per non-planar surface 12 ', 13', or, as shown in Fig. 5, a plurality of fibers per non-planar surface 12 ', 13' may be arranged.
  • the above-mentioned preferred arrangements and embodiments apply analogously.
  • FIG. 6a a concave cut is shown in FIG. 6a and a substantially convex cut is shown in FIG. 6b, in which the surfaces 3 and 6 are located.
  • the surfaces 3 and 6 are shaped to be concave (Fig. 6c) or convex (6d) segments of cylinders whose axes cross the median plane 14, or concave (Fig. 6c) or convex (6d) segments of spheres.
  • FIG. 7 shows a schematic representation in the section of an alternative embodiment of an optical sensor according to the invention in the region of the sensor head. Unlike in Fig. 2a are in this embodiment, the ends of the first fiber 1 and the second fiber 4 in the same plane, parallel to the diaphragm 8. Subsequently, at these fiber ends 2 ', 5', a light-conducting insert body 7 is arranged.
  • This insert 7 fulfills the same function as the fiber ends 2, 5 of the arrangement in Fig. 2a, which are integrally connected to the two fibers 1, 4.
  • the light exit surface 3 'and the light entry surface 6' of the insert body are arranged facing away from each other as in the other described arrangements.
  • the beam path in this alternative embodiment is substantially the same as in the previously described arrangement and has the same advantages as described.
  • the beam path in the region of the insert body is merely somewhat conical, since the reflective sidewalls of a light guide in the area of the insert body 7 are missing. All embodiments described above, in particular those described in Figures 4-6, can be correspondingly achieve with an insert body 7 with the same advantages described.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Fluid Pressure (AREA)

Abstract

L'invention concerne un capteur de pression optique se fondant sur des mesures d'intensité lumineuse, comprenant au moins une membrane 8 ainsi que deux fibres optiques parallèles 1, 4. Au moins une première fibre 1 présente une extrémité de fibre 2 et une surface de sortie de lumière 3, 3' pour émettre de la lumière 10 en direction de la membrane 8. Au moins une deuxième fibre 4 présente une extrémité de fibre 5 et une surface d'entrée de lumière 6, 6' pour recevoir et transmettre la lumière 10 réfléchie sur la membrane 8. Selon l'invention, la surface de sortie de lumière 3, 3' et la surface d'entrée de lumière 6, 6' des deux fibres 1, 4 sont disposées en opposition mutuelle. En utilisation, le trajet des rayons de la lumière 10 est ainsi modifié de telle sorte que la part de lumière reçue par la fibre réceptrice 4 dépend fortement de la position de la membrane.
EP07816272A 2006-11-27 2007-11-26 Capteur de pression optique avec au moins deux fibres optiques Withdrawn EP2095084A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH19142006 2006-11-27
PCT/CH2007/000589 WO2008064506A2 (fr) 2006-11-27 2007-11-26 Capteur de pression optique avec au moins deux fibres optiques

Publications (1)

Publication Number Publication Date
EP2095084A2 true EP2095084A2 (fr) 2009-09-02

Family

ID=37686019

Family Applications (1)

Application Number Title Priority Date Filing Date
EP07816272A Withdrawn EP2095084A2 (fr) 2006-11-27 2007-11-26 Capteur de pression optique avec au moins deux fibres optiques

Country Status (4)

Country Link
US (1) US8074501B2 (fr)
EP (1) EP2095084A2 (fr)
JP (1) JP5345547B2 (fr)
WO (1) WO2008064506A2 (fr)

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TWI397847B (zh) 2009-09-17 2013-06-01 Pixart Imaging Inc 光學觸控裝置及其光學觸控裝置的定位方法
JP5349997B2 (ja) * 2009-02-10 2013-11-20 株式会社ケネック 光学式変位計
US8330961B1 (en) 2010-07-15 2012-12-11 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Optical multi-species gas monitoring sensor and system
DE102011085329A1 (de) * 2011-10-27 2013-05-02 Continental Teves Ag & Co. Ohg Optischer Druckfühler und Verfahren zum optischen Erfühlen eines Drucks
ES2556810T3 (es) * 2012-02-07 2016-01-20 Sensoptic Sa Elemento óptico sensor de fuerza e instrumento microquirúrgico
ITMI20130138A1 (it) * 2013-01-31 2014-08-01 Laser Point S R L Sensore ottico per misure di pressione senza contatto.
GB2511803B (en) 2013-03-14 2015-07-29 Kidde Tech Inc Pneumatic sensing apparatus
US9360388B2 (en) * 2013-06-07 2016-06-07 Baker Hughes Incorporated Pressure sensing system and method of housing a pressure sensor
US20160139337A1 (en) * 2013-10-17 2016-05-19 Ofs Fitel, Llc Dual-Ended Optical Fiber Pathway
US9875585B2 (en) 2014-05-29 2018-01-23 Lang-Mekra North America, Llc Vehicle video display verification system
US20170307437A1 (en) * 2014-10-01 2017-10-26 Phonoptics Opto-mechanical transducer for the detection of vibrations
JP6801158B2 (ja) * 2017-03-13 2020-12-16 オムロン株式会社 環境センサ
WO2019126967A1 (fr) * 2017-12-25 2019-07-04 深圳市得道健康管理有限公司 Appareil de mesure de déformation de surface et capteur de déformation de surface de celui-ci
EP3755007A1 (fr) * 2019-06-19 2020-12-23 Infineon Technologies AG Dispositif pour détecter un mouvement d'une surface déflectrice
CN114486054A (zh) * 2022-04-02 2022-05-13 成都凯天电子股份有限公司 一种高温光纤动态压力传感器及其压力计算方法

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Also Published As

Publication number Publication date
US8074501B2 (en) 2011-12-13
WO2008064506A3 (fr) 2008-07-17
WO2008064506A2 (fr) 2008-06-05
JP2010511146A (ja) 2010-04-08
US20100064785A1 (en) 2010-03-18
JP5345547B2 (ja) 2013-11-20

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