GB2141821A - Pressure sensor - Google Patents

Pressure sensor Download PDF

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Publication number
GB2141821A
GB2141821A GB08410541A GB8410541A GB2141821A GB 2141821 A GB2141821 A GB 2141821A GB 08410541 A GB08410541 A GB 08410541A GB 8410541 A GB8410541 A GB 8410541A GB 2141821 A GB2141821 A GB 2141821A
Authority
GB
United Kingdom
Prior art keywords
fibres
pressure
sensor
fibre
light transmission
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.)
Granted
Application number
GB08410541A
Other versions
GB8410541D0 (en
GB2141821B (en
Inventor
Edmund Sergio Robert Sikora
Anthony John Walkden
Peter Richard Wallace
Philip Alexander Barber
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.)
General Electric Co PLC
Original Assignee
General Electric Co PLC
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
Priority claimed from GB838311169A external-priority patent/GB8311169D0/en
Application filed by General Electric Co PLC filed Critical General Electric Co PLC
Priority to GB08410541A priority Critical patent/GB2141821B/en
Publication of GB8410541D0 publication Critical patent/GB8410541D0/en
Publication of GB2141821A publication Critical patent/GB2141821A/en
Application granted granted Critical
Publication of GB2141821B publication Critical patent/GB2141821B/en
Expired legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
    • G01L1/247—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet using distributed sensing elements, e.g. microcapsules

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

Abstract

A pressure sensor comprises a first set of optical fibres (5) disposed in generally parallel planar relationship, a second set of optical fibres (7) disposed in generally parallel planar relationship overlapping the first set of fibres and extending transverse thereto, and means (15 - 25) for determining the light transmission loss of each fibre. In use of the sensor, the application of pressure on the sensor causes a slight bending of the fibres at the or each cross-over point of the two sets of fibres in the region of application of the pressure, with a resulting change in the light transmission loss of such fibres, thereby indicating that pressure has been applied. By identifying the particular fibres in the two sets whose light transmission losses have been changed, an indication of the location of the region of application of pressure may be obtained. Applications to keyboards, and to indicate the shape of the object applying the pressure, are mentioned. <IMAGE>

Description

SPECIFICATION Pressure Sensors This invention relates to pressure sensors.
It is an object of the present invention to provide a pressure sensor of robust simple construction and capable of providing an output indicative of the position on the sensor at which pressure has been applied.
Acording to the present invention a pressure sensor comprises a first set of optical fibres disposed in generally parallel planar relationship; a second set of optical fibres disposed in generally parallel planar relationship, overlapping said first set of fibres, the fibres of the second set extending transverse to the fibres of the first set; a support means for the fibres which is deformable by applied pressure at least in regions where the fibres cross, thereby to allow such applied pressure to correspondingly deform the fibres at such regions, and indicating means responsive to the light transmission loss in each fibre.
In use of a sensor according to the invention the application of pressure to the sensor causes a slight bending of the fibres at the or each cross-over point of two fibres in the region of application of pressure, with a resulting change in the light transmission loss of such fibres, thereby indicating that pressure has been applied. By identifying the particular fibres in the two sets whose light transmission losses have been changed, an indication of the location of the region of application of pressure may be obtained.
One pressure sensor in accordance with the invention will now be described, by way of example, with reference to the accompanying drawing in which Figure lisa schematic diagram of the sensor; and Figure 2 is a diagrammatic perspective view of part of the sensor.
The sensor includes a pressure sensing element comprising two plates 1 and 3 between which are sandwiched two sets of three optical fibres 5 or 7.
The fibres 5 of one set run along respective parallel spaced apart channels 9 in one plate 1 and the fibres 7 of the other set run along similar respective parallel spaced apart channels 11 in the other plate 3, the channels 9 in the plate 1 extending at right angles to the channels in the other plate 3.
At each point where a fibre 5 or 7 of one set crosses a fibre 7 or 5 of the other set, the fibre in lower channel 9 loops into and out of the upper channel 11 and vice versa, as shown in Figure 2.
In the upper plate 3, at each of the nine cross-over points of two fibres, there is provided a spring loaded push-button 13 which when pushed causes the associated two fibres to push against one another, thereby causing each of the two fibres to be pushed further into the channel extending at right angles to it into which it loops, and reducing the radii of curvature of the loop. The spring loading of the push-buttons may be provided by the fibres tending to straighten themselves or by separate springs.
The fibres 5 and 7 are each connected at one end to a respective one of six light emitting diodes (LEDS) 15 via further lengths of fibres 17.
The other end of each of the fibres 5 and 7 is connected via a respective further length of fibre 19 to a large area photo detector diode 21.
The output of the photo detector diode 21 is fed to a control circuit 23 which operates a display 25 in dependence on the output of diode 21 and controls the operation of the LEDS 15.
In operation of the sensor, the circuit 23 flashes the LEDS 15 in turn and monitors the resulting signals produced by the detector diode 21.
When a push-button 13 is pressed, the increased bending of the associated two fibres 5 and 7 increases the light transmission loss in those two fibres. The particular button 13 which has been pressed is identified by the control circuit 23 from the relative intensities of the outputs of the diode 21 for the different fibres, and the display 25 is operated by the control circuit 23 to indicate visually which button 13 has been pressed.
If desired the control circuit 23 and display 25 may be arranged to give also an indication of the degree of increase in light transmission loss and hence to give an indication as to how hard a button 13 has been pressed.
It will be appreciated that whilst in the particular sensor described by way of example pressure is applied only at points defined by push-buttons, other sensors in accordance with the invention may be arranged to respond to pressure applied at any point of an area defined by the sets of optical fibres.
In such an arrangementthetwo sets of fibres are suitably mounted on a support member consisting of flexible material, the spacing between adjacent fibres being made sufficiently small to ensure that at least one cross-over point of two fibres is affected wherever pressure is applied. The support member may comprise two planar channelled portions of a form similar to the plates 1 and 3 described above, but without push-buttons.
It will be appreciated that a pressure sensor in accordance with the invention finds application not only to indicate where pressure has been applied, and/or to indicate the shape of an object applying pressure, but also for keyboard and like applications.
1. A pressure sensor comprising a first set of optical fibres disposed in generally parallel planar relationship; a second set of optical fibres disposed in generally parallel planar relationship, overlapping said first set of fibres, the fibres of the second set extending transverse to the fibres of the first set; a support means for the fibres which is deformable by applied pressure at least in regions where the fibres cross, thereby to allow such applied pressure to correspondingly deform the fibres at such regions, and indicating means responsive to the light transmission loss in each fibre.
2. A sensor according to Claim 1 wherein said indicating means comprises a respective light source at one end of each fibre; a light detector responsive to light transmitted through each fibre from the associated source; means for operating said light sources in turn; and means for monitoring
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Pressure Sensors This invention relates to pressure sensors. It is an object of the present invention to provide a pressure sensor of robust simple construction and capable of providing an output indicative of the position on the sensor at which pressure has been applied. Acording to the present invention a pressure sensor comprises a first set of optical fibres disposed in generally parallel planar relationship; a second set of optical fibres disposed in generally parallel planar relationship, overlapping said first set of fibres, the fibres of the second set extending transverse to the fibres of the first set; a support means for the fibres which is deformable by applied pressure at least in regions where the fibres cross, thereby to allow such applied pressure to correspondingly deform the fibres at such regions, and indicating means responsive to the light transmission loss in each fibre. In use of a sensor according to the invention the application of pressure to the sensor causes a slight bending of the fibres at the or each cross-over point of two fibres in the region of application of pressure, with a resulting change in the light transmission loss of such fibres, thereby indicating that pressure has been applied. By identifying the particular fibres in the two sets whose light transmission losses have been changed, an indication of the location of the region of application of pressure may be obtained. One pressure sensor in accordance with the invention will now be described, by way of example, with reference to the accompanying drawing in which Figure lisa schematic diagram of the sensor; and Figure 2 is a diagrammatic perspective view of part of the sensor. The sensor includes a pressure sensing element comprising two plates 1 and 3 between which are sandwiched two sets of three optical fibres 5 or 7. The fibres 5 of one set run along respective parallel spaced apart channels 9 in one plate 1 and the fibres 7 of the other set run along similar respective parallel spaced apart channels 11 in the other plate 3, the channels 9 in the plate 1 extending at right angles to the channels in the other plate 3. At each point where a fibre 5 or 7 of one set crosses a fibre 7 or 5 of the other set, the fibre in lower channel 9 loops into and out of the upper channel 11 and vice versa, as shown in Figure 2. In the upper plate 3, at each of the nine cross-over points of two fibres, there is provided a spring loaded push-button 13 which when pushed causes the associated two fibres to push against one another, thereby causing each of the two fibres to be pushed further into the channel extending at right angles to it into which it loops, and reducing the radii of curvature of the loop. The spring loading of the push-buttons may be provided by the fibres tending to straighten themselves or by separate springs. The fibres 5 and 7 are each connected at one end to a respective one of six light emitting diodes (LEDS) 15 via further lengths of fibres 17. The other end of each of the fibres 5 and 7 is connected via a respective further length of fibre 19 to a large area photo detector diode 21. The output of the photo detector diode 21 is fed to a control circuit 23 which operates a display 25 in dependence on the output of diode 21 and controls the operation of the LEDS 15. In operation of the sensor, the circuit 23 flashes the LEDS 15 in turn and monitors the resulting signals produced by the detector diode 21. When a push-button 13 is pressed, the increased bending of the associated two fibres 5 and 7 increases the light transmission loss in those two fibres. The particular button 13 which has been pressed is identified by the control circuit 23 from the relative intensities of the outputs of the diode 21 for the different fibres, and the display 25 is operated by the control circuit 23 to indicate visually which button 13 has been pressed. If desired the control circuit 23 and display 25 may be arranged to give also an indication of the degree of increase in light transmission loss and hence to give an indication as to how hard a button 13 has been pressed. It will be appreciated that whilst in the particular sensor described by way of example pressure is applied only at points defined by push-buttons, other sensors in accordance with the invention may be arranged to respond to pressure applied at any point of an area defined by the sets of optical fibres. In such an arrangementthetwo sets of fibres are suitably mounted on a support member consisting of flexible material, the spacing between adjacent fibres being made sufficiently small to ensure that at least one cross-over point of two fibres is affected wherever pressure is applied. The support member may comprise two planar channelled portions of a form similar to the plates 1 and 3 described above, but without push-buttons. It will be appreciated that a pressure sensor in accordance with the invention finds application not only to indicate where pressure has been applied, and/or to indicate the shape of an object applying pressure, but also for keyboard and like applications. CLAIMS
1. A pressure sensor comprising a first set of optical fibres disposed in generally parallel planar relationship; a second set of optical fibres disposed in generally parallel planar relationship, overlapping said first set of fibres, the fibres of the second set extending transverse to the fibres of the first set; a support means for the fibres which is deformable by applied pressure at least in regions where the fibres cross, thereby to allow such applied pressure to correspondingly deform the fibres at such regions, and indicating means responsive to the light transmission loss in each fibre.
2. A sensor according to Claim 1 wherein said indicating means comprises a respective light source at one end of each fibre; a light detector responsive to light transmitted through each fibre from the associated source; means for operating said light sources in turn; and means for monitoring the output of the light detector.
3. A sensor according to Claim 1 or Claim 2 wherein said support means substantially consists of deformable material.
4. A sensor according to Claim 1 or Claim 2 wherein said support means consists of substantially rigid material with a deformable portion in the region of each cross-over point of two fibres.
5. A sensor according to Claim 4 wherein each said deformable portion comprises a spring-loaded push button.
6. A sensor according to any one of the preceding claims wherein each of the first set of fibres extends along a respective channel in a face of a first plate forming part of said support means; each of the second set of fibres extends along a respective channel in a face of a second plate, forming part of the support means, the two plates being disposed with their channelled faces adjacent and each fibre, where it crosses another fibre, being arranged to loop into the channel along which that other fibre extends.
7. A sensor according to any one of the preceding claims wherein said indicating means is arranged to give an indication of the degree of change in light transmission loss in each fibre.
8. A pressure sensor substantially as hereinbefore described with reference to the accompanying drawing.
GB08410541A 1983-04-25 1984-04-25 Pressure sensor Expired GB2141821B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08410541A GB2141821B (en) 1983-04-25 1984-04-25 Pressure sensor

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB838311169A GB8311169D0 (en) 1983-04-25 1983-04-25 Pressure sensors
GB08410541A GB2141821B (en) 1983-04-25 1984-04-25 Pressure sensor

Publications (3)

Publication Number Publication Date
GB8410541D0 GB8410541D0 (en) 1984-05-31
GB2141821A true GB2141821A (en) 1985-01-03
GB2141821B GB2141821B (en) 1986-05-29

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Family Applications (1)

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GB08410541A Expired GB2141821B (en) 1983-04-25 1984-04-25 Pressure sensor

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GB (1) GB2141821B (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2199938A (en) * 1987-01-20 1988-07-20 De La Rue Syst Force detection assembly
DE3715693C1 (en) * 1987-05-12 1988-09-01 Deutsche Forsch Luft Raumfahrt Flat, tactile sensor
FR2637080A1 (en) * 1988-09-27 1990-03-30 Labo Electronique Physique FIBER OPTIC PRESSURE SENSOR
WO2003069294A1 (en) * 2002-02-11 2003-08-21 Leoni Bordnetz-Systeme Gmbh & Co Kg Pressure sensor comprising an optical waveguide, and method for detecting pressure
WO2014194944A1 (en) * 2013-06-05 2014-12-11 Ev Group E. Thallner Gmbh Measuring device and method for ascertaining a pressure map
US20190064012A1 (en) * 2016-02-26 2019-02-28 Technische Universiteit Eindhoven Optical waveguide system for 2-dimensional location sensing

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2199938A (en) * 1987-01-20 1988-07-20 De La Rue Syst Force detection assembly
DE3715693C1 (en) * 1987-05-12 1988-09-01 Deutsche Forsch Luft Raumfahrt Flat, tactile sensor
US4886361A (en) * 1987-05-12 1989-12-12 Versuchsanstalt fur Luft Flat tactile sensor
FR2637080A1 (en) * 1988-09-27 1990-03-30 Labo Electronique Physique FIBER OPTIC PRESSURE SENSOR
EP0365062A1 (en) * 1988-09-27 1990-04-25 Laboratoires D'electronique Philips Optical fibre pressure sensor
WO2003069294A1 (en) * 2002-02-11 2003-08-21 Leoni Bordnetz-Systeme Gmbh & Co Kg Pressure sensor comprising an optical waveguide, and method for detecting pressure
JP2005517920A (en) * 2002-02-11 2005-06-16 レオニ アクチエンゲゼルシャフト Pressure sensor with optical waveguide and pressure detection method
US6912912B2 (en) 2002-02-11 2005-07-05 Leoni Bordnetz-Systeme Gmbh & Co. Kg Pressure sensor having an optical waveguide and method for pressure detection
JP4800579B2 (en) * 2002-02-11 2011-10-26 レオニ ボルトネッツ−ジステーメ ゲゼルシャフト ミット ベシュレンクテル ハフツング Pressure sensor with optical waveguide and pressure detection method
WO2014194944A1 (en) * 2013-06-05 2014-12-11 Ev Group E. Thallner Gmbh Measuring device and method for ascertaining a pressure map
CN105283744A (en) * 2013-06-05 2016-01-27 Ev集团E·索尔纳有限责任公司 Measuring device and method for ascertaining a pressure map
JP2016521849A (en) * 2013-06-05 2016-07-25 エーファウ・グループ・エー・タルナー・ゲーエムベーハー Measuring apparatus and method for measuring pressure map
US10024741B2 (en) 2013-06-05 2018-07-17 Ev Group E. Thallner Gmbh Measuring device and method for ascertaining a pressure map
US20190064012A1 (en) * 2016-02-26 2019-02-28 Technische Universiteit Eindhoven Optical waveguide system for 2-dimensional location sensing
US10768060B2 (en) * 2016-02-26 2020-09-08 Technische Universiteit Eindhoven Optical waveguide system for 2-dimensional location sensing

Also Published As

Publication number Publication date
GB8410541D0 (en) 1984-05-31
GB2141821B (en) 1986-05-29

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