WO1995020845A1 - Systeme de transmission infrarouge de donnees - Google Patents

Systeme de transmission infrarouge de donnees Download PDF

Info

Publication number
WO1995020845A1
WO1995020845A1 PCT/GB1995/000167 GB9500167W WO9520845A1 WO 1995020845 A1 WO1995020845 A1 WO 1995020845A1 GB 9500167 W GB9500167 W GB 9500167W WO 9520845 A1 WO9520845 A1 WO 9520845A1
Authority
WO
WIPO (PCT)
Prior art keywords
transmitter
transmitters
unit
lens
receivers
Prior art date
Application number
PCT/GB1995/000167
Other languages
English (en)
Inventor
John Robert Emmett
Original Assignee
Lee Communications Limited
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 Lee Communications Limited filed Critical Lee Communications Limited
Priority to JP7519945A priority Critical patent/JPH08510613A/ja
Priority to EP95906446A priority patent/EP0694233A1/fr
Priority to AU14639/95A priority patent/AU1463995A/en
Publication of WO1995020845A1 publication Critical patent/WO1995020845A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/03—Arrangements for fault recovery
    • H04B10/032—Arrangements for fault recovery using working and protection systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
    • H04B10/112—Line-of-sight transmission over an extended range
    • H04B10/1123—Bidirectional transmission
    • H04B10/1125—Bidirectional transmission using a single common optical path
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
    • H04B10/112—Line-of-sight transmission over an extended range
    • H04B10/1123—Bidirectional transmission
    • H04B10/1127—Bidirectional transmission using two distinct parallel optical paths

Definitions

  • This invention relates to a data transmission system, and particularly to one in which the data are transmitted by modulating a beam of coherent radiation in the infra-red portion of the spectrum-
  • Data transmission systems employing a single infra-red transmitter in the line of sight of a single infra-red receiver are well known.
  • One obvious example is in the remote control device for a television set, wherein the differently-modulated output signals of the remote control unit cause the set to change channels; to change the volume of the audio output, or the brightness of the picture, etc.
  • Other systems are known in industrial settings, e.g. as described in EP-A-0034859.
  • the present invention aims at increasing the continuity of reception of data-bearing signals transmitted by modulated infra-red beams over considerable distances, by using two or more transmitters at each transmitter unit, and two or more receivers at each receiver unit, with the same data being transmitted on each beam.
  • the present invention provides a system for communicating data by the modulation and demodulation of a beam of coherent infra-red radiation, including a transmitter unit and a receiver unit each being sightable from the other, wherein the transmitter unit includes a housing, at least two separate transmitters mounted within the housing and means for adjusting the angle of the output beam from each transmitter to a limited extent relative to a front face of the housing, whereby the receiver unit may receive data from one or both transmitters.
  • the receiver unit also has a housing which includes at least two receivers each including a lens adapted to focus incoming radiation on a photodetector.
  • Figure 1 is a view from the front of a combined transmitter/receiver unit of the present invention
  • Figure 2 is a view similar to Figure 1 of a different transmitter/receiver unit
  • Figure 3 is a section on the line III-III of Figure 2, showing two parallel receivers and one transmitter;
  • Figure 4 is a scrap view of that part encircled in Figure 3, and drawn to a larger scale, and
  • FIG. 5 is a plan view of a transmitter beam steering device shown in the previous figures, in which Figure 4 is a section on line IV-IV of Figure
  • each transmitter unit intended to communicate data unilaterally to a remote receiver, with each transmitter unit having two transmitters of modulated infra-red beams, and with each receiver having two receivers for such beams, in most commercial forms of the present invention it is envisaged that bilateral communication would take place between two transmitter/receiver
  • the transmitter unit has a housing 3 which includes four transmitters 4 of modulated infra-red radiation, and two receivers 6 intended to receive such radiation and demodulate it to extract the data.
  • An optional feature shown in Figure 1 is the provision of an alignment device 8 intended to produce a visible beam which can be aligned optically with a common optical axis of the remote transceiver.
  • the transceivers 2 and 10 could be associated with each other when it is desired to transmit data with greater certainty in one direction along a two-way communication channel than in the opposite direction.
  • the higher continuity of reception is ensured by modulating the four transmitters 4 of transceiver 2 with the same data, and arranging for each transmitter to be aligned optically with one of the four receivers 6 on transceiver 10.
  • a lower degree of continuity of data transmission in the opposite direction arises from the fact that only two transmitters work in that direction, in co-operation with only two receivers.
  • the two transceivers would each have four transmitters and four receivers.
  • Each transmitter 4 uses an infra-red laser diode 15 ( Figure 4) to produce its output beam.
  • the beam is modulated by the data to be transmitted, and the modulated beam falls on a lens 14 also carried by a mounting plate 16, which is in turn secured to a support flange 18 by means of three mounting screws 20.
  • the manner in which the screws may be manipulated to steer the output beam are described below in connection with Figure 4.
  • the transceiver 10 In order to align two transceivers, such as 2 and 10, the transceiver 10 is provided with a tapped hole 12. Into this hole is screw-threaded a mount for a reflector, such as of the trihedral or ballotini type, which throws incident light back to its source.
  • the laser in alignment device 8 (which may be steerable) is energised and housing 3 manipulated until a 'flash* of light from the receiver housing is observed, indicating that the tightly-focussed beam from device 8 is incident on the receiver. Thereafter the reflector is unscrewed to expose the adjacent receivers to incident infra-red radiation.
  • Each receiver 6 includes a large-diameter focusing lens 22 intended to receive the incident beam of coherent modulated radiation and bring it to a focus on a photodetector 24.
  • both of the photodetectors 24 are mounted on the same printed circuit board 26, so that the positions of the photodetectors are predetermined by the manu acturer, and cannot be adjusted by the user.
  • the demodulation etc. circuity does not form part of the subject-matter of this invention, and so is not described herein in any greater detail. In practice it would lie close to the printed circuit board 26, being connected to it by leads which are not shown in the drawings.
  • the output beam is steered by means of the adjustable mounting plate 16.
  • the plate is secured to a support flange 18 by means of three screws 20 arranged at the apices of an equilateral triangle. This arrangement ensures that the mounting plate 16 can be tilted in any direction lying within a solid cone by differential rotation of the screws 20.
  • each screw is circumscribed by a helical compression spring 28, having one end bearing on the inside surface of flange 18, and the other end bearing on an opposite face of mounting plate 16.
  • the function of spring 28 is to keep the head of screw 20 in rotary contact with flange 18, or with an anti-friction washer 30.
  • Rotation of lens 14 is effective to move it along the optical axis of laser 15, so as to colli ate its output beam or cause it to fan out over a small solid angle. Causing a beam to fan out reduces its effective range but gives greater latitude, by enabling data to be received over a wider area within the effective range.
  • Another unusual application of the present invention is to increasing the security of people travelling in lifts (elevators).
  • Data relating to the security of people within the lift may be transmitted by the system of the present invention by attaching a transmitter to the external base of the lift, and aligning it optically with a receiver positioned directly below it. In this way data can be transmitted from the lift to remote security etc. personnel, and also in the opposite direction if desired, should the normal telephone in a lift be put out of action for whatever reason.
  • the present invention provides a data communication system of high integrity, achieved by the use of multi-beam transmitters and receivers.
  • ' ulti' in this specification is meant - two or more -. While the preferred system ensures high integrity of data transmission by using four data transmission beams from the same transmitter unit, the lower guarantee of integrity provided by the use of only two transmitters might be perfectly acceptable in some applications of the present invention.
  • both or all transmitters of one transceiver would be transmitting the same data, this is not essential.
  • the present invention encompasses both or all transmitters being aimed at different targets (which may be a single, fixed or mobile, receiver) ; being of different divergencies, and therefore of different effective ranges, and carrying different data.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)

Abstract

L'invention se rapporte à un système de communication de données par faisceaux modulés de rayons infrarouges qui met en ÷uvre des unités émettrices et réceptrices alignées. On améliore l'intégrité de la communication de données, en comparaison à des émetteurs et des récepteurs individuels, en utilisant maintenant au moins deux émetteurs opposés à au moins deux récepteurs, afin d'obtenir une meilleure redondance du signal pour annuler l'effet de l'interruption d'un faisceau unique. La divergence du faisceau de sortie émanant de chaque émetteur peut être modifiée par le déplacement d'une lentille d'un type désiré le long de l'axe du faisceau, et sa direction peut être modifiée par l'inclinaison de l'émetteur. Il est possible de faire tomber les faisceaux de sortie sur pratiquement la même zone afin d'améliorer l'intégrité de la transmission de données, ou il est possible de faire chevaucher les zones entre elles, partiellement, afin d'obtenir une zone ou des zones de forme choisie, à des distances spécifiées à partir de l'émetteur, des données identiques ou différentes pouvant être réceptionnées à n'importe quel point dans ces zones.
PCT/GB1995/000167 1994-01-28 1995-01-27 Systeme de transmission infrarouge de donnees WO1995020845A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP7519945A JPH08510613A (ja) 1994-01-28 1995-01-27 赤外線データ伝送装置
EP95906446A EP0694233A1 (fr) 1994-01-28 1995-01-27 Systeme de transmission de donnees par infrarouges
AU14639/95A AU1463995A (en) 1994-01-28 1995-01-27 Infrared data transmission system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9401643.3 1994-01-28
GB9401643A GB9401643D0 (en) 1994-01-28 1994-01-28 Data transmission system

Publications (1)

Publication Number Publication Date
WO1995020845A1 true WO1995020845A1 (fr) 1995-08-03

Family

ID=10749480

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1995/000167 WO1995020845A1 (fr) 1994-01-28 1995-01-27 Systeme de transmission infrarouge de donnees

Country Status (5)

Country Link
EP (1) EP0694233A1 (fr)
JP (1) JPH08510613A (fr)
AU (1) AU1463995A (fr)
GB (1) GB9401643D0 (fr)
WO (1) WO1995020845A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19501539C2 (de) * 1994-04-25 2000-07-06 Matsushita Electric Ind Co Ltd Elektrooptischer Sende-/Empfangsmodul
EP1231732A1 (fr) * 2001-02-03 2002-08-14 Alcatel Méthode pour la transmission de signaux optiques en espace libre
EP1233549A2 (fr) 2001-02-15 2002-08-21 NTT DoCoMo, Inc. Systeme de Communication
WO2002071656A2 (fr) * 2001-03-01 2002-09-12 Sceptre Communications Limited Systeme de communication optique sans fil en duplex
WO2003025882A1 (fr) * 2001-09-12 2003-03-27 Jonathan Storbeck Telecommande en forme de pistolet

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2141258A (en) * 1983-04-05 1984-12-12 Motorola Israel Ltd Electro-optical line of sight communications apparatus
EP0434004A1 (fr) * 1989-12-21 1991-06-26 Gte Laboratories Incorporated Système de transmission utilisant des connections optiques parallèles pour obtenir une étendue dynamique améliorée
EP0566352A1 (fr) * 1992-04-11 1993-10-20 Sony Corporation Liaison optique atmosphérique
WO1994001942A1 (fr) * 1992-07-01 1994-01-20 Motorola Inc. Systeme de communication infrarouge a debit binaire eleve permettant de maitriser le brouillage dans la propagation par trajets simples

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2141258A (en) * 1983-04-05 1984-12-12 Motorola Israel Ltd Electro-optical line of sight communications apparatus
EP0434004A1 (fr) * 1989-12-21 1991-06-26 Gte Laboratories Incorporated Système de transmission utilisant des connections optiques parallèles pour obtenir une étendue dynamique améliorée
EP0566352A1 (fr) * 1992-04-11 1993-10-20 Sony Corporation Liaison optique atmosphérique
WO1994001942A1 (fr) * 1992-07-01 1994-01-20 Motorola Inc. Systeme de communication infrarouge a debit binaire eleve permettant de maitriser le brouillage dans la propagation par trajets simples

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19501539C2 (de) * 1994-04-25 2000-07-06 Matsushita Electric Ind Co Ltd Elektrooptischer Sende-/Empfangsmodul
EP1231732A1 (fr) * 2001-02-03 2002-08-14 Alcatel Méthode pour la transmission de signaux optiques en espace libre
EP1233549A2 (fr) 2001-02-15 2002-08-21 NTT DoCoMo, Inc. Systeme de Communication
EP1233549A3 (fr) * 2001-02-15 2006-03-15 NTT DoCoMo, Inc. Systeme de Communication
US7116909B2 (en) 2001-02-15 2006-10-03 Ntt Docomo, Inc. Information transmission system and information transmission method, and, optical space transmission system and optical space transmission method
WO2002071656A2 (fr) * 2001-03-01 2002-09-12 Sceptre Communications Limited Systeme de communication optique sans fil en duplex
WO2002071656A3 (fr) * 2001-03-01 2003-09-04 Sceptre Comm Ltd Systeme de communication optique sans fil en duplex
US7369775B2 (en) 2001-03-01 2008-05-06 Freewire Communications Ltd. Wireless duplex optical communication system
WO2003025882A1 (fr) * 2001-09-12 2003-03-27 Jonathan Storbeck Telecommande en forme de pistolet

Also Published As

Publication number Publication date
GB9401643D0 (en) 1994-03-23
JPH08510613A (ja) 1996-11-05
EP0694233A1 (fr) 1996-01-31
AU1463995A (en) 1995-08-15

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