GB2189047A - Fibre optic switch - Google Patents

Fibre optic switch Download PDF

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Publication number
GB2189047A
GB2189047A GB08707834A GB8707834A GB2189047A GB 2189047 A GB2189047 A GB 2189047A GB 08707834 A GB08707834 A GB 08707834A GB 8707834 A GB8707834 A GB 8707834A GB 2189047 A GB2189047 A GB 2189047A
Authority
GB
United Kingdom
Prior art keywords
fibre optic
control means
fibre
reed
signal
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
GB08707834A
Other versions
GB2189047B (en
GB8707834D0 (en
Inventor
Brian David Hamblin
Rheinhold Barlian
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.)
BARTEC BARLIAN
Original Assignee
BARTEC BARLIAN
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 BARTEC BARLIAN filed Critical BARTEC BARLIAN
Publication of GB8707834D0 publication Critical patent/GB8707834D0/en
Publication of GB2189047A publication Critical patent/GB2189047A/en
Application granted granted Critical
Publication of GB2189047B publication Critical patent/GB2189047B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • 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
    • G02B6/35—Optical coupling means having switching means
    • G02B6/3564—Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details
    • G02B6/3566—Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details involving bending a beam, e.g. with cantilever
    • 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
    • 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
    • G02B6/35—Optical coupling means having switching means
    • G02B6/351—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements
    • G02B6/3512—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being reflective, e.g. mirror
    • 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
    • G02B6/35—Optical coupling means having switching means
    • G02B6/354—Switching arrangements, i.e. number of input/output ports and interconnection types
    • G02B6/3544—2D constellations, i.e. with switching elements and switched beams located in a plane
    • G02B6/3548—1xN switch, i.e. one input and a selectable single output of N possible outputs
    • G02B6/355—1x2 switch, i.e. one input and a selectable single output of two possible outputs
    • 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
    • G02B6/35—Optical coupling means having switching means
    • G02B6/354—Switching arrangements, i.e. number of input/output ports and interconnection types
    • G02B6/3544—2D constellations, i.e. with switching elements and switched beams located in a plane
    • G02B6/3548—1xN switch, i.e. one input and a selectable single output of N possible outputs
    • G02B6/3552—1x1 switch, e.g. on/off switch
    • 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
    • G02B6/35—Optical coupling means having switching means
    • G02B6/3564—Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details
    • G02B6/3568—Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details characterised by the actuating force
    • G02B6/357—Electrostatic force
    • 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
    • G02B6/35—Optical coupling means having switching means
    • G02B6/3564—Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details
    • G02B6/3568—Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details characterised by the actuating force
    • G02B6/3572—Magnetic force
    • 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
    • G02B6/35—Optical coupling means having switching means
    • G02B6/3564—Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details
    • G02B6/3568—Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details characterised by the actuating force
    • G02B6/3576—Temperature or heat actuation

Abstract

A control means includes a housing 10 and two fibre optics 12, 14 terminating within the housing. A signal from one fibre optic is reflected onto the other fibre optic by a surface 22 mounted on a reed 20. When the reed is moved the signal between the fibre optics is interrupted or attenuated. A single fibre optic capable of transmitting at least two separate signals may be used instead of the fibre optics 12 and 14. <IMAGE>

Description

SPECIFICATION Control means This invention relates to control means more particularly but not exclusively control means for use in hazardous areas.
Control of equipment in hazardous areas may be of a low energy type so as to preclude initiation of an explosion. In the areas of greatest risk, known as zone 0, no conventional electrical supply is permitted and the control means, for example a switch, must be such that energy produced is not sufficient to produce incandescent sparks.
Amongst the various kinds of control means magnetically operable switches have been used. However, the reliability of such switches can sometimes be impaired by external effects. Increasingly, therefore, optical control, using for example fibre optics to convey a signal, is being used because such controls are not affected by magnetic fields or other electrically induced effects. These optical controls can operate by interruption or attenuation of the light signal. However, they are not operable by mechanical means.
According to the invention there is provided a control means comprising a housing, first and second fibre optic means terminating within the housing, and movable means in the housing movable from a position in which a signal can be transmitted from the first fibre optic means to the second fibre optic means and a second position in which the signal from the first fibre optic means to the second fibre optic means is interrupted or attenuated.
The movable means is preferably a reed and the control of movement of the reed may be effected in different ways, the particular mode being chosen having regard to the use to which the control is to be put. For example the reed can be moved by mechanical means operable outside the housing manually or in some other way. The reed can be caused to move in response to variations in temperature and/or pressure. In another embodiment of the invention the reed is movable in response to magnetic electrostatic, conductive forces and combinations thereof.
In its simplest construction the control means of the invention comprises two fibre optic means terminating within the housing.
The invention includes control means having more than two fibre optic means terminating within the housing. Movement of the reed can be arranged such as to cause transmission of a signal from the first fibre optic means to the second fibre optic means to be switched to the third or other fibre optic means.
By appropriate movement of the reed the control means of the invention can operate in a digital or analogue mode.
Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a diagrammatic representation of one form of control means; Figures 2-5 illustrate further embodiments of the control means; Figure 6 is a circuit diagram showing how the control means of the invention can be used Figure 7 is yet a further embodiment of the control means.
In the various embodiments like parts have been given the same reference numerals.
Referring to Fig. 1 the control means comprises a housing 10 which may be of glass, plastics or other material. The housing need not be completely closed. Fibre optics 12, 14 extend from a socket, plug or other connecting means 16 on the exterior of the housing into the housing as illustrated. The free ends of the fibre optics are preferably inclined towards each other as at 18.
A flexible reed 20 is fixed to the housing so that its free end lies adjacent the free ends of the fibre optics. A reflecting surface 22 is fixed to the free end of the reed 20.
In normal operation a light signal from one fibre optic is reflected by 22 to the other fibre optic. When the reed is moved, for example into the position 24 shown in dotted lines, the reflective means 22 is no longer in position to transmit a signal from one fibre optic to the other.
The movement of the reed to interrupt the signal can be effected in many different ways for example by an electromagnet located outside the housing by means adapted to respond to variations in pressure, by means responsive to temperature such as a bimetal incorporated with, or attached to the reed, or by means adapted to bring a permanent magnet into the proximity of the housing. When the means influencing movement of the reed into the position 24 is disabled, the reed returns under its own resilience to its normal position and transmission between the fibre optics is restored.
In the embodiment just described the normal position of the reed maintains transmission between the fibre optics. It will be understood that the control means can be arranged such that normally the reed is in the position where there is no transmission between the fibre optics and the reed is movable into the position where such transmission is effected.
The control means of the invention can be arranged as a change over switch and used for example to switch a signal to another circuit instead of just interrupting the signal as in the two pole embodiment of Fig. 1. For example in the embodiment of Fig. 2 an additional fibre optic means 30 is included alongside the fibre optics 12 and 14. When the reed is in its normal position a signal can be transmitted between fibre optics 30 and 12.
In its other position 24 a signal can be transmitted between fibre optics 30 and 14.
Other ways of controlling the signal between fibre optics can be adapted instead of reflection as described in the embodiments of Figs. 1 and 2. For example, as shown in Fig.
3, an opaque member 32 can be fixed to the reed so as to interrupt a signal between the free ends of aligned fibre optics 34 and 36.
When the reed is moved to the dotted position 24 a signal can be transmitted between the fibre optics. In the embodiment of Fig. 3 the fibre optics are shown as extending towards each other from opposite ends of the housing, a second socket 38 being provided for fibre optic 36. Other arrangements can be used, for example the fibre optics can extend from one end of the housing only with the free ends thereof being directed towards each other.
The invention also includes arrangements in which fibre optic means are movable between positions in which a signal is transmitted between the said fibre optic means and another fibre optic means and in which the signals between said fibre optic means is interrupted.
In the embodiment of the invention shown in Fig. 4 the reed is linked to one of the aligned fibre optics 36. Movement of the reed will bring about non-alignment of the fibre optics and thus interrupt any signal passing between them.
In the embodiment of Fig. 5 a fibre optic 50 is disposed in a flexible arm 52 of a mounting block 54. A second fibre optic 56 is arranged to be directed at the free end of the arm 52.
The arm can be moved by any means to create, attenuate or interrupt communication between the fibre optics 50 and 56.
In a variant of this kind of arrangement a fibre optic can be moved so as to be alignable with a selected one from a plurality of fibre optics. Movement of the movable fibre optic can be effected in any way. For example the free end of the movable fibre optic can be mounted in a rotatable member for alignment with one of a plurality of optic fibres arranged in a suitable pattern for example a circle, a rectangle, a cross and so on.
It will be apparent from the foregoing that the control means of the invention utilises no electric power and, therefore, there is no possibility of any spark being generated upon operation thereof. The invention will, therefore, meet the requirements for ali kinds of hazardous areas including zone 0 where only intrinsically safe equipment can be used. The control means of the invention can be used in installations where parameters are currently being sensed by electrically powered means for example the pressure, temperature, flow rate, vibration and the like of material in tanks or like storage.
An example of the use of the control means of the invention is illustrated by the circuit of Fig. 6. Light from an LED 40 is transmitted by fibre optic 42 to a control means of the invention 44 located in a hazardous area. Depending upon the condition of the control means light will be transmitted (or not) by fibre optic 45 to a transformer 46, the output from which can actuate a relay 48 in a safe area. An assembly of LED, control means, transformer and if desired amplifiers can be formed as a module with appropriate sockets for connection.
The fibre optic means can all be comprised within a single fibre optic and an example of that is shown in Fig. 7. A single fibre optic 60 which is capable of transmitting at least two separate signals extends from socket 16 into the housing. A signal from the free end of the fibre optic is reflected from the reflected ing surface 22 back down the same fibre optic 60. When the reed is moved into the position shown in dotted lines the signal path is broken.
The control means of the invention can be constructed in the form of a cartridge which can be fitted, as required in existing circuitry and switch housings.
The invention is not restricted to the embodiments just described and many modifications can be made. For example in place of a reed a reflective temperature sensitive material such as a bimetal or polarised barrier may be used to transmit the signal from one fibre optic to another. Changes in temperature may alter the shape or other properties of the reflective material and hence alter the amount of light transmitted between the optical fibres in the control means. A similar arrangement can be constructed using reflective material whose shape will alter in response to other factors, such as pressure.
In another modification of the invention the reed or equivalent means is adapted to move a barrier of variable light transmissability between one fibre optic and another. The effect of this arrangement is to produce an analogue signal representing the amount of light transmitted which is itself dependent on the position of the reed.
If desired the reed or equivalent movable means can be adapted, for example by the provision of springs or the like, to operate with a snap action so as to provide for quick make and/or break.

Claims (8)

1. A control means comprising a housing, first and second fibre optic means terminating within the housing, and movable means in the housing movable from a position in which a signal can be transmitted from the first fibre optic means to the second fibre optic means and a second position in which the signal from the first fibre optic means to the second fibre optic means is interrupted or attenuated.
2. Control means as claimed in Claim 1, wherein the movable means is a reed.
3. Control means as claimed in Claim 1 or Claim 2, wherein movement of the movable means is effected by mechanical, thermal, magnetic or electrical means or a combination of two or more thereof.
4. Control means as claimed in any preceding claim, wherein the fibre optic means are comprised within a single fibre optic.
5. Control means as claimed in any of claims 1 to 3, wherein the fibre optic means comprises a plurality of fibre optics.
6. Control means as claimed in any preceding claim wherein the movable means comprises a reflective surface.
7. Control means as claimed in any preceding claim, wherein the movable means comprises a shutter.
8. Control means substantially as described herein with reference to any one of Figs. 1 to 5 or 7.
GB8707834A 1986-04-08 1987-04-02 Optical control means. Expired - Fee Related GB2189047B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB868608556A GB8608556D0 (en) 1986-04-08 1986-04-08 Control means

Publications (3)

Publication Number Publication Date
GB8707834D0 GB8707834D0 (en) 1987-05-07
GB2189047A true GB2189047A (en) 1987-10-14
GB2189047B GB2189047B (en) 1990-11-21

Family

ID=10595870

Family Applications (2)

Application Number Title Priority Date Filing Date
GB868608556A Pending GB8608556D0 (en) 1986-04-08 1986-04-08 Control means
GB8707834A Expired - Fee Related GB2189047B (en) 1986-04-08 1987-04-02 Optical control means.

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB868608556A Pending GB8608556D0 (en) 1986-04-08 1986-04-08 Control means

Country Status (1)

Country Link
GB (2) GB8608556D0 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2632423A1 (en) * 1988-06-06 1989-12-08 Photonetics OPTICAL SWITCHING DEVICE
US5024500A (en) * 1987-04-02 1991-06-18 British Telecommunications Public Limited Company Cantilever beam radiation deflector assembly

Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1426475A (en) * 1973-06-21 1976-02-25 Plessey Co Ltd Optical fibre switch
US3976876A (en) * 1972-06-19 1976-08-24 Brocker Dale C Signal control apparatus
GB1520596A (en) * 1975-07-14 1978-08-09 Siemens Ag Switch for light
GB2014751A (en) * 1978-02-17 1979-08-30 Trw Inc Optical switching
US4170731A (en) * 1976-08-30 1979-10-09 Miller Fluid Power Corporation Fiber optic control modules and system employing the same
US4189206A (en) * 1977-03-14 1980-02-19 Fujitsu Limited Optical switching device
GB2030319A (en) * 1978-09-21 1980-04-02 Siemens Ag Optical fibre switching arrangements
GB1581614A (en) * 1978-01-24 1980-12-17 Standard Telephones Cables Ltd Fibre optic switch device
GB2051351A (en) * 1979-04-20 1981-01-14 Perren B Sensor for a monitoring apparatus
GB1588496A (en) * 1977-12-29 1981-04-23 Cutler Hammer World Trade Inc Fibre optic switch
US4337995A (en) * 1978-11-17 1982-07-06 Hitachi, Ltd. Switch for optical transmission lines
US4376566A (en) * 1980-03-03 1983-03-15 Sheltered Workshop For The Disabled, Inc. Fiber optic switching method and apparatus with flexible shutter
US4415229A (en) * 1981-08-24 1983-11-15 Bell Telephone Laboratories, Incorporated Optical fiber switch apparatus
US4512627A (en) * 1982-12-13 1985-04-23 At&T Bell Laboratories Optical fiber switch, electromagnetic actuating apparatus with permanent magnet latch control

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3976876A (en) * 1972-06-19 1976-08-24 Brocker Dale C Signal control apparatus
GB1426475A (en) * 1973-06-21 1976-02-25 Plessey Co Ltd Optical fibre switch
GB1520596A (en) * 1975-07-14 1978-08-09 Siemens Ag Switch for light
US4170731A (en) * 1976-08-30 1979-10-09 Miller Fluid Power Corporation Fiber optic control modules and system employing the same
US4189206A (en) * 1977-03-14 1980-02-19 Fujitsu Limited Optical switching device
GB1588496A (en) * 1977-12-29 1981-04-23 Cutler Hammer World Trade Inc Fibre optic switch
GB1581614A (en) * 1978-01-24 1980-12-17 Standard Telephones Cables Ltd Fibre optic switch device
GB2014751A (en) * 1978-02-17 1979-08-30 Trw Inc Optical switching
GB2030319A (en) * 1978-09-21 1980-04-02 Siemens Ag Optical fibre switching arrangements
US4337995A (en) * 1978-11-17 1982-07-06 Hitachi, Ltd. Switch for optical transmission lines
GB2051351A (en) * 1979-04-20 1981-01-14 Perren B Sensor for a monitoring apparatus
US4376566A (en) * 1980-03-03 1983-03-15 Sheltered Workshop For The Disabled, Inc. Fiber optic switching method and apparatus with flexible shutter
US4415229A (en) * 1981-08-24 1983-11-15 Bell Telephone Laboratories, Incorporated Optical fiber switch apparatus
US4512627A (en) * 1982-12-13 1985-04-23 At&T Bell Laboratories Optical fiber switch, electromagnetic actuating apparatus with permanent magnet latch control

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5024500A (en) * 1987-04-02 1991-06-18 British Telecommunications Public Limited Company Cantilever beam radiation deflector assembly
FR2632423A1 (en) * 1988-06-06 1989-12-08 Photonetics OPTICAL SWITCHING DEVICE
EP0346202A1 (en) * 1988-06-06 1989-12-13 Photonetics S.A. Device for optical switching

Also Published As

Publication number Publication date
GB8608556D0 (en) 1986-05-14
GB2189047B (en) 1990-11-21
GB8707834D0 (en) 1987-05-07

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19950402