GB2133137A - Fibre optic light switch - Google Patents

Abstract

A fibre optic light switch, for controlling a dimmer/switch unit, comprises a light emitter and a light detector, the detector output controlling the dimmer/switch unit. Optical fibres 18, 22 connect the emitter and detector to a switch unit wherein the optical fibres are positioned side by side such that the placing of a finger 26 in front of the fibres causes light to pass from the emitter to the detector to control the dimmer/switch unit. Further optical fibres may connect the emitter and detector to a further switch unit, to provide two-way switching. <IMAGE>

Description

SPECIFICATION Fibre optic light switch The present invention relates to switches and more particularly to control switches operated using optical fibres.

According to the present invention there is provided a switch for electrical lamps or other apparatus including an electronic switch/control unit, a light source connected to a first optical fibre, a light detector connected to a second optical fibre, in which the opposite ends of the first and second fibres are positioned such that light emitted from one fibre can be reflected down the other fibre to the detector and in which the output of the detector is connected for operation of the electronic switch/control unit.

Preferably the ends of the fibres are mounted within a unit pointing through a transparent window such that a finger placed in front of the window will cause reflection of the light from the source to the detector. In a preferred embodiment allowing two way switching third and fourth optical fibres are respectively connected to the source and the detector, the opposite ends of the third and fourth fibres being positioned at the ends of the first and second fibres to form a second switch unit which is operable to actuate the switch/control unit.

Embodiments of the present invention will now be described, with reference to the accompanying drawings in which : Figure 1 shows in diagrammatic form a switching system according to the present invention using as an a ample a dimmer/switch unit for controlling one or more electric lamps and Figure 2 shows in greater detail a switch unit suitable for the system of Figure 1.

Referring now to Figure 1 of the drawings a lamp or lamps 10 is controlled by an electronic dimmer/switch unit 12 of a commercially available type. To this unit 1 2 are connected a light source 14 and a detector 16. A first optical fibre 18 is connected to the light source 14 and supplies light to a switch unit 20. A second optical fibre 22 is connected to the detector 1 6 and to the switch unit 20. The optical fibres can be of the plastic type which are relatively cheap.

The switch unit illustrated in Figure 2 comprises a transparent plastic window 24 to which the ends of fibres 18, 22 are secured in a spaced apart relationship. The fibres are mounted such that if a finger iilustrated diagrammatically at 26 wrought, as shown, into close relationship to the plastic window 24 a detectable amount of light from the light source 14 will be returned to the detector to operate the dimmer/switch circuit 1 2 to control the brightness of the lamp or lamps 10.

Two or more way switching can be achieved by connecting in another switch unit 28 as shown.

A visible light source may be used in which case the switch units would be visible at night.

The source would be A.C. modulated to distinguish the light from general lighting sources.

The advantages of this type of switching system are that assuming an existing dimmer/switch unit is fitted then the cost of the detector and light source (LED) can be relatively small and the optical fibre can be easily installed e.g. recessed in plaster or taped to a wall and the switch unit 20 can be extremely cheap.

The switch unit 20 can be used in difficult environments e.g. bathrooms, kitchen, external positions where water ingress is a problem.

Multiple switch systems are easily provided and the switch unit can readily be made visible in the dark.

The apparatus can be used to control other pieces of apparatus for example remote control of curtains or other domestic or industrial appliances which are electrically or hydraulically operable.

Claims (Filed on 5.1.84) 1. A switch for electrical lamps or other apparatus including an electronic switch/control unit, a light source connected to a first optical fibre, a light detector connected to a second optical fibre, in which the opposite ends of the first and second fibres are positioned such that the light emitted from one fibre can be reflected down the other fibre to the detector and in which the output of the detector is connected for operation of the electronic switch/control unit.

2. A switch for electrical lamps or other apparatus as claimed in claim 1 in which the ends of the fibres are mounted within a unit pointing through a transparent window such that a finger placed in front of the window will cause reflection of the light from the source to the detector.

3. A switch for electrical lamps or other apparatus as claimed in claim 2 allowing two way switching third and fourth optical fibres are respectively connected to the source and the detector, the opposite ends of the third and fourth fibres being positioned at the ends of the first and second fibres to form a second switch unit which is operable to actuate the switch/control unit.

4. A switch for electrical lamps or other apparatus substantially as described with reference to the accompanying figures.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Fibre optic light switch The present invention relates to switches and more particularly to control switches operated using optical fibres. According to the present invention there is provided a switch for electrical lamps or other apparatus including an electronic switch/control unit, a light source connected to a first optical fibre, a light detector connected to a second optical fibre, in which the opposite ends of the first and second fibres are positioned such that light emitted from one fibre can be reflected down the other fibre to the detector and in which the output of the detector is connected for operation of the electronic switch/control unit. Preferably the ends of the fibres are mounted within a unit pointing through a transparent window such that a finger placed in front of the window will cause reflection of the light from the source to the detector. In a preferred embodiment allowing two way switching third and fourth optical fibres are respectively connected to the source and the detector, the opposite ends of the third and fourth fibres being positioned at the ends of the first and second fibres to form a second switch unit which is operable to actuate the switch/control unit. Embodiments of the present invention will now be described, with reference to the accompanying drawings in which : Figure 1 shows in diagrammatic form a switching system according to the present invention using as an a ample a dimmer/switch unit for controlling one or more electric lamps and Figure 2 shows in greater detail a switch unit suitable for the system of Figure 1. Referring now to Figure 1 of the drawings a lamp or lamps 10 is controlled by an electronic dimmer/switch unit 12 of a commercially available type. To this unit 1 2 are connected a light source 14 and a detector 16. A first optical fibre 18 is connected to the light source 14 and supplies light to a switch unit 20. A second optical fibre 22 is connected to the detector 1 6 and to the switch unit 20. The optical fibres can be of the plastic type which are relatively cheap. The switch unit illustrated in Figure 2 comprises a transparent plastic window 24 to which the ends of fibres 18, 22 are secured in a spaced apart relationship. The fibres are mounted such that if a finger iilustrated diagrammatically at 26 wrought, as shown, into close relationship to the plastic window 24 a detectable amount of light from the light source 14 will be returned to the detector to operate the dimmer/switch circuit 1 2 to control the brightness of the lamp or lamps 10. Two or more way switching can be achieved by connecting in another switch unit 28 as shown. A visible light source may be used in which case the switch units would be visible at night. The source would be A.C. modulated to distinguish the light from general lighting sources. The advantages of this type of switching system are that assuming an existing dimmer/switch unit is fitted then the cost of the detector and light source (LED) can be relatively small and the optical fibre can be easily installed e.g. recessed in plaster or taped to a wall and the switch unit 20 can be extremely cheap. The switch unit 20 can be used in difficult environments e.g. bathrooms, kitchen, external positions where water ingress is a problem. Multiple switch systems are easily provided and the switch unit can readily be made visible in the dark. The apparatus can be used to control other pieces of apparatus for example remote control of curtains or other domestic or industrial appliances which are electrically or hydraulically operable. Claims (Filed on 5.1.84)

1. A switch for electrical lamps or other apparatus including an electronic switch/control unit, a light source connected to a first optical fibre, a light detector connected to a second optical fibre, in which the opposite ends of the first and second fibres are positioned such that the light emitted from one fibre can be reflected down the other fibre to the detector and in which the output of the detector is connected for operation of the electronic switch/control unit.

2. A switch for electrical lamps or other apparatus as claimed in claim 1 in which the ends of the fibres are mounted within a unit pointing through a transparent window such that a finger placed in front of the window will cause reflection of the light from the source to the detector.

3. A switch for electrical lamps or other apparatus as claimed in claim 2 allowing two way switching third and fourth optical fibres are respectively connected to the source and the detector, the opposite ends of the third and fourth fibres being positioned at the ends of the first and second fibres to form a second switch unit which is operable to actuate the switch/control unit.

4. A switch for electrical lamps or other apparatus substantially as described with reference to the accompanying figures.