Classifications

• • G—PHYSICS
  • G08—SIGNALLING
  • G08G—TRAFFIC CONTROL SYSTEMS
  • G08G1/00—Traffic control systems for road vehicles
  • G08G1/09—Arrangements for giving variable traffic instructions
  • G08G1/095—Traffic lights
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B61—RAILWAYS
  • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
  • B61L5/00—Local operating mechanisms for points or track-mounted scotch-blocks; Visible or audible signals; Local operating mechanisms for visible or audible signals
  • B61L5/12—Visible signals
  • B61L5/18—Light signals; Mechanisms associated therewith, e.g. blinders
  • B61L5/1809—Daylight signals
  • B61L5/1827—Daylight signals using light sources of different colours and a common optical system
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V5/00—Refractors for light sources
  • F21V5/008—Combination of two or more successive refractors along an optical axis
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V5/00—Refractors for light sources
  • F21V5/04—Refractors for light sources of lens shape
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B61—RAILWAYS
  • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
  • B61L2207/00—Features of light signals
  • B61L2207/02—Features of light signals using light-emitting diodes [LEDs]
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21W—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO USES OR APPLICATIONS OF LIGHTING DEVICES OR SYSTEMS
  • F21W2111/00—Use or application of lighting devices or systems for signalling, marking or indicating, not provided for in codes F21W2102/00 – F21W2107/00
  • F21W2111/02—Use or application of lighting devices or systems for signalling, marking or indicating, not provided for in codes F21W2102/00 – F21W2107/00 for roads, paths or the like
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
  • F21Y2107/00—Light sources with three-dimensionally disposed light-generating elements
  • F21Y2107/10—Light sources with three-dimensionally disposed light-generating elements on concave supports or substrates, e.g. on the inner side of bowl-shaped supports
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
  • F21Y2115/00—Light-generating elements of semiconductor light sources
  • F21Y2115/10—Light-emitting diodes [LED]

Definitions

• This invention has arisen specifically in relation to railway traffic signalling lights but is not necessarily so limited in application.
• LEDs Semiconductor light-emitting diodes
• tungsten filament lamps are generally accepted as being inherently very much more reliable than tungsten filament lamps, but available light intensity is many orders of magnitude less. Indeed, even the dramatic improvements in LEDs evidenced by commercially available single devices with light outputs as high as fifteen candelas or so each do not begin to compare with tungsten filament lamps in terms of direct practical replacement for railway signalling lights, or any other applications with similar requirements. In relation to railway signalling lights it is a particular object of this invention to find a solution permitting practical use of LEDs.
• a plurality of LEDs sufficient even after failure of some LED(s) to produce a totality of light emissions that is adequate for intended usage is deployed in an areal array in combination with emitted light concentrating means as an effectively geometrically distributed light source with emitted light having substantially parallel directionality as supplied to and through output "glass” means (which might be of transparent plastics material, of course).
• LEDs will be simultaneously energised, say at least 40, typically 50 to 80 or more.
• Minimum excess of LEDs over the number nominally adequate for intended usage can be in accordance with known performance and failure rate of LEDs concerned and target servicing/replacement intervals, but is conveniently more and with sensing of intermediate number of failures, say 2%, perhaps 5% - 10% or more, redundancy and sensing anywhere desired below. Sensing is preferably accompanied by indication.
• One suitable geometry for such array of LEDs is generally concave, say following prescribed curvature (s) , say parabolic, or approximating thereto as adjacent sub- array components of lesser curvature (s) or substantially flat.
• a corresponding suitable arrangement of the light concentrating means may generally follow the geometry of the array of LEDs, say as plural condensing lens elements that might correspond with appropriate sub-arrays of said array, and may serve to focus to a position having useful functional similarity to adequate tungsten lamp filament and customary output "glass", say or near at focus for Fresnel lens provisions.
• the combination of the array of LEDs and the light condensing lens elements can operate after the manner of an areally distributed light source concentrated by focussing so that all or most output light is as though forward emission directly from a tungsten lamp at said position, say effectively as resembling a tungsten lamp with a reflector focussing on the lamp filament rather than producing at least some other reflection, perhaps parallel beam, say to avoid heating problems from re-focussing onto the tungsten lamp.
• suitable said condensing lens elements could be of a compound nature, say with medial or inner edge-adjacent parts producing substantially position-focussed light and outer parts producing substantially parallel beam light, or vice versa.
• the combination of the array of LEDs and the light concentrating means may simplify output lens requirements, as could first discussed position-focussing for substantially wholly forwardly directed light from such position, say a point or line.
• Compound partly position focussed and partly otherwise directed light could facilitate use of existing output "glass" systems, i.e. as for tungsten lamp units.
• lens elements and/or sub-arrays of LEDs in generally corresponding geometrical configurations, say represented by appropriately configured individual substrates carrying same, the lens elements and their configured transparent substrate might be moulded as an integral unit that would allow simple production even for different and/or compound lens element parts, i.e. with only some increase in initial tooling costs, perhaps not a great increase given impact of computer aided design and computer controlled tool-making techniques.
• the geometries of the LED array and lens element substrates could differ, say to aid assembly at least of the LEDs in banks/trees thereof, within what is compensatable by differing lens elements, that could include (for this or other purpose) varifocal features (rather than merely above-indicated bifocal features) .
• Connection of LEDs in plural banks/trees thereof in appropriate serial/parallel relation for electrical drive current facilitates further connection and interconnection, including with any desired degree of redundancy and alternative selection for active operation, say automatically at sensing some prescribed one or more failures of LEDs or blocks/trees thereof.
• Suitable geometries for the array of LEDs and the light concentrating means can have much less curvatures,- indeed, be substantially flat in terms of substrate (s) or other carrier sheet (s) for the LEDs and for plural condensing lens elements, or as overall configuration of moulded multiple lens element means.
• a substantially coplanar array of substantially identical plano-convex condensing lens elements will effectively have substantially coplanar foci in or near to which focal plane the array of LEDs can be positioned.
• sub-groups of three LEDs a few millimetres in diameter were disposed close together in mounting holes with centres in a line centred relative to a respective plano-convex condensing lens element having a diameter of about 20 millimetres and a focal length of about 100 millimetres. Occurrence of rings of brightness was noted using such sub-groups of LEDs and condensing lens elements, and overall brightness was readily adjusted by selectively altering the population of selected sub-groups specifically not loading one of the three possible in-line LED sites. Whilst such selection should be calculable mathematically with sufficiently detailed areal brightness analysis, selection by trial and error is seen as practical.
• LEDs include differently angled lines and numbers of LED sites with or without a central LED, sites for LEDs at apices or corners of notional triangles (not necessarily equilateral) , rectangles (not necessarily square) , and polygons (not necessarily regular) .
• Other alternatives include positioning in front of or behind true focal points of simple condensing lenses at least by up to matching intercept spacings of focal lines with spread of LEDs for corresponding sub-groups of LEDs and condensing lens elements, or even variation of curvature or peripheral shape of the condensing lens elements to produce a small but spread focal area rather than single focal point.
• One particular concise array of condensing lens elements is generally hexagonal with one more lens element in successive rows inwardly from any side.
• a regular hex- agonal array with five lens element sites per side leads to 61 sites in total of which one was left unused for reasons related to sensing failure (s) of LED(s).
• Suitable sensing can be by such simple expedient as dividing the totality of LEDs into equal groups each associated with its own current sensing circuitry with the groups wired in parallel relative to overall sensing circuitry.
• the relationship of populations of these groups to the totality of LEDs can be such that loss of light from a whole group leaves overall emitted light above a relevant minimum brightness/light output standard.
• the inter- relationship between these groups and the above sub-groups can readily be such that even loss of light from a whole group of LEDs will not result in any sub-group losing more than one LED, preferably no two adjacent sub-groups losing less than one LED between them, or as may be otherwise desired or preferred.
• An inescapable feature of predominantly near parallel, only slightly divergent output beams of light is that the lighted states will not be observable outside the beams, say at the side of a warning light.
• This is overcome by another aspect of this invention, namely a part of or patch on a beam output "glass” that is of at least diffusing nature, even sideways light-directing nature, say at an edge of such "glass".
• Implication of use without diffusion of output light is to be taken as preference, at least for the high light output required of railway signalling/warning lamps, but not necessarily limiting, say relative to other applications found to be feasible.
• suitable LEDs are available to give red, amber and green light signals directly, i.e. through a clear "glass”.
• a further aspect of this invention resides in providing for communication of intelligible information by modulation of the signal light beam as such, say at least for audio and/or visual display of a "stop" message along with a "stop" signal light state.
• stop message could be of a pre-recorded standard type, and there can be other standard messages to accompany any signal light state, whether continuously transmitted or initiated by actual sensed presence of an approaching train or by expectation, say based on scheduled approach time.
• Further special messages are equally readily transmitted, whether called up from a repertoire of pre-recorded messages inten- ded to suit various circumstances or corresponding to use of a microphone.
• Engines and cabs will, of course, then need to be equipped with a light-sensitive sensing transducer and suitable demodulation means to produce drive signals for an audio loudspeaker (or head-phones) and/or a visual display, which provision can be of a quite simple and inexpensive nature.
• Such modulated signal light beam communication provision is well-suited for use along with further communication provision.
• Convenience and advantage is seen in such further provision also being of a modulated light beam type, even where, as is particularly envisaged, the signal light means is associated with a different light transducer cell, say for short range communication at least with a stopped train then quite close to the signal lights as would suit any special circumstances, including providing information to be passed on to passengers of a passenger train.
• Separation of availability of the first-mentioned and further communication facilities is readily achieved, say relative to the latter being enabled only after the train has got so close to the signals that its related light transducer is by then out of the relevant signal beam, whether or not such engine-associated transducer is shared with the further communication provision, as is feasible, perhaps advantageous.
• the two communic- ations systems can be of so much the same or similar type as to share transmission modulation and/or reception demodulation means .
• preferred such further communication are readily extended to initiate and service data communication, whether telemetry from the tain or further information to the train and its telemetry and/or computer systems etc control, further whether or not always initiated or only so if the train slows or stops.
• Figure 1 shows outline for a first embodiment
• Figure 2 shows outline for a second embodiment
• Figure 3 indicates useful arrangements of condensing lens elements and LEDs
• Figure 4 is an outline wiring and fault sensing diagram
• Figure 5 is an alternative outline wiring diagram
• Figure 6 is an outline block diagram for light modulated communications provision (s) .
• a generally concave array 111 of LEDs 112 is shown with chain-dash ray lines through an also generally concave light concentrating arrangement 115 of conden- sing lens elements 16 shown both focussing light to position 121 and otherwise passing light in overlapping relation to output lens system 125 shown specifically as of double convex Fresnel lens type 126A, B through and out of which light ray lines go continuous.
• illustrated light ray lines are intended to be helpful, the actual situation of highly diffuse light from the LEDs 112 is difficult to illustrate, and a viable conception may well be as a suffusion of light between the LEDs 112 and the lens elements 116 with the latter generally concentrating most if not all of the emitted light to the position 121.
• the LEDs 112 are shown carried by a generally concave substrate 113 that should be non-transparent and may be light reflective within its concavity, and/or peripherally about spacing from the condensing lens system 115.
• the LEDs 112 may be connected in banks or trees and/or on ind- ividual substrates (not shown) that could fit onto facets in the concavity of the overall substrate 113 or into a plural frame-like alternative, say with electrical connections through to the generally convex rear of substrate 113.
• the lens elements 116 are shown carried by a transparent generally concave substrate 117, which may have flat facets 118 in its concavity and an also faceted or smoothly convex other surface 119.
• the whole (116, 117) might well be integrally moulded as a unit from transparent, probably plastics, material of suitable refractive index; and the lens elements 116 may be of simple convex shapes or of more complex compound shapes, say at least with flattened tops as implied for some unfocussed through-passage of light, or otherwise, say for substantially parallel beam output (not shown) .
• the position 121 will be a line. If the substrates 113 and 117 are concave also through the plane of the [drawing] , the position 121 can have less length, in the limit be a point.
• Such individual LED bank/ tree substrates could correspond one-for-one with the condensing lens elements 116.
• a substantially flat planar array 211 of LEDs 212 is shown with chain-dash light ray lines through a substantially parallel light concentrating arrangement 215 of condensing lens elements 216 shown (on similar simplified basis to Figure 1) both producing substantially parallel beam light and otherwise passing light in over- lapping slightly divergent relation to and through an output "glass" provision 225 shown substantially flat.
• the LEDs 212 are shown carried by a substantially flat sheet, plate or substrate 213 that is non-transparent , even preferably light reflective facing the condensing lens elements 216, that could be in one-for-one correspondence with the LEDs 212, see solid lines of Figure 2, or with subgroups thereof, see dashed in Figure 2 and LED mounting positions as in-line triplets at 312A, B, C in Figure 3 as was realised in a prototype by slightly siamesed mounting holes in a bright metal plate 313 (visible in superposition) .
• the lens elements 216 are shown carried by a flat sheet, plate or substrate 217 that could be transparent or, and perhaps preferably light reflective facing the LEDs 212, see lens element mounting position 316A corresponding to one of the LED position triplets 312A, B, C in Figure 3, as was realised in a prototype by closely arranged lens mounting holes (indicated mostly by centres 316X in registration with central ones 312B of the LED positions in a bright metal plate 317, say to present individual plano- convex lens elements with their flat bases coplanar with inner surface of the plate (216, 217 in Figure 2) .
• Preferred practical alternatives for volume production are being developed as a printed circuit board for the LED carrier 217 and as a composite moulded light condensing lens plate of transparent plastic material of suitable refractive index for integral lens element formations .
• the lay-out geometry shown in Figure 3 is particularly compact as a regular hexagonal array of the condensing lens elements 316 shown on a conveniently circular carrier 317, see partial intercalation of successive "rows" with progr- essive one position increases from each edge of the array.
• the hexagonal array of Figure 3 allows 61 such positions, affording up to 183 LEDs for full triplet sub-groups. Numbers for lens element positions per side are, of course, 37 lens element positions and up to 111 LEDs.
• Figure 4 shows the totality of LEDs divided into six equal groups 411 - 416 severally connected in parallel arms - 416) and arm (421 - 426) having an associated current monitoring circuit 431 - 436, and the whole circuit 410 having direct current supply 441, parallel capacitive 442 and resistance/warning light 443/444 branches, and resis- tive overall monitoring via resister 445 and a.c. source/ detector 446.
• the LED groups 411 - 416 each contain no more than one LED from each lens element related subgroup (312A, B, C) , preferably adjacent rows thereof.
• a further inventive provision hereof arises from predominance of low-divergence main overall light output, and need for close-range observation of light state outside such beam.
• part or an addition 226 to overall output "glass" 225 is indicated in Figure 2 for directing/ diverting part of output light much more sideways, say as an outer sectoral lens part/addition 226, conveniently in/ on a convex output "glass” 225 as shown dashed in Figure 2, say at position 326 in Figure 3.
• Alternative fault detection etc strategies include normal first operation with part only of the totality of LEDs 212 lit up, say one of the groups 411 - 416 as a stand -by brought in after another of the groups 411 - 416, or other predetermined number of the LEDs 212, fails. Indeed, any possible LED positions not used in pursuit of multiples in and of groups/arms 411-416/421-426 could be used additionally or alternatively for fault indication, say in said or another output "glass" part or addition for sideways or other viewing.
• LEDs 512 is indicated in doubletons and singletons, as have been found to be adequate for required light output from such provision of LED locations as first indicated for Figure 3. Wiring is indicated as simply being wholly in parallel for each and all of the LEDs, see between full array traversing voltage lines 551, 552 and branching therefrom to each LED. LED doubletons 512D are shown only in the middle three rows, specifically at ends thereof then inwardly alternating with singletons. Warning of exceeding whatever may be the desired extent of tolerable failure of the LEDs is indicated by current measuring circuitry 555, normally exceeded minimum threshold value setting/sensing means 556, and wiring means 557 operative on loss of output 558 from the latter (556) .
• signals control 611 is shown for lamp LEDs drive means 613 with a modulator 614 interposed before the lamp LEDs 612 as such for superimposing standard message (s) from pre-recorded source 615 as modulation of the lamp beam.
• photodet- ection means 621 has modulated information recovered from its output 622 by demodulator 623 for visual display at 624 and/or audio reproduction at loudspeaker or headphones 625.
• pre-recorded standard message provision is seen as a train-must-stop message accompanying a red light signal, either continuously or in response to any normal track-associated train-approaching sensing/detection and/or time-related train-approach expectation as input to or part of the signals control 611.
• train-must-stop message accompanying a red light signal, either continuously or in response to any normal track-associated train-approaching sensing/detection and/or time-related train-approach expectation as input to or part of the signals control 611.
• special message (s) 632 whether also pre-recorded, perhaps loop-recorded or otherwise supplied at 633 as and when required, or selected from some repertoire of pre- recordings at 632; in any event, alternatively or additionally provided to the modulator 614, and intendedly demodulated and made available in the engine cab visually at display 624 and/or audibly at speaker 625.
• Further light modulated/demodulated communications provision is shown by way of light emitting/detecting cells 635 and 636 associated with the signals and with the engine, respectively.
• the engine-associated light cell 636 may, perhaps preferably usually will, be the same as and incorporate the functions of the photodetector 621, at least if not incompatible with envisaged much shorter range of communication for these further provisions using light cells 635 and 636, typically close to the signals concer- ned, and usable at least when a train has stopped for a red signal light.
• Preferred two-way voice communication is indicated by way of control, transmission modulation and reception demodulation means 637C, T, R associated with the signals 638C, T, R associated with the engine each with further associated microphone 641S, E and speaker 642S, E provisions that may conveniently be embodied in a telephone-like handset, including hands-free type, at least at the engine and as implied by the drawing relative to sharing of the speaker 625. Recording provisions are further indicated at 643S, E at both of the signals location and the engine cab, whether for so-called "black box" or other purpose.
• Figure 6 further shows preferred two-way data communication by way of control transmission and receiving means 644C,T,R associated with the signals and similarly controlled from 631, and 645C, T, R at the engine cab, along with associated data stores 646 and 647, respectively; and telemetry module 648 at the engine cab.
• control transmission and receiving means 644C,T,R associated with the signals and similarly controlled from 631, and 645C, T, R at the engine cab, along with associated data stores 646 and 647, respectively; and telemetry module 648 at the engine cab.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Led Device Packages (AREA)
• Non-Portable Lighting Devices Or Systems Thereof (AREA)
• Eye Examination Apparatus (AREA)
• Traffic Control Systems (AREA)
• Train Traffic Observation, Control, And Security (AREA)

Applications Claiming Priority (5)

Publications (2)

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• 1998
  • 1998-09-01 GB GB9818801A patent/GB2329011B/en not_active Expired - Fee Related
  • 1998-09-01 ES ES98940445T patent/ES2197498T3/es not_active Expired - Lifetime
  • 1998-09-01 DE DE69813255T patent/DE69813255T2/de not_active Expired - Fee Related
  • 1998-09-01 EP EP98940445A patent/EP1012023B1/fr not_active Expired - Lifetime
  • 1998-09-01 AU AU88769/98A patent/AU8876998A/en not_active Abandoned
  • 1998-09-01 WO PCT/GB1998/002620 patent/WO1999011498A1/fr active IP Right Grant
  • 1998-09-01 AT AT98940445T patent/ATE236821T1/de not_active IP Right Cessation

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