EP1352544A2 - Signalisation a diodes electroluminescentes permettant de detecter une degradation de lumiere, dotee d'un collecteur a conduite de lumiere - Google Patents

Signalisation a diodes electroluminescentes permettant de detecter une degradation de lumiere, dotee d'un collecteur a conduite de lumiere

Info

Publication number
EP1352544A2
EP1352544A2 EP01273916A EP01273916A EP1352544A2 EP 1352544 A2 EP1352544 A2 EP 1352544A2 EP 01273916 A EP01273916 A EP 01273916A EP 01273916 A EP01273916 A EP 01273916A EP 1352544 A2 EP1352544 A2 EP 1352544A2
Authority
EP
European Patent Office
Prior art keywords
led
led signal
signal
light
housing
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.)
Withdrawn
Application number
EP01273916A
Other languages
German (de)
English (en)
Inventor
Patrick Martineau
Jean-Simon Bourgault
Eden Dubuc
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.)
Current Lighting Solutions LLC
Original Assignee
Gelcore LLC
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 US09/756,670 external-priority patent/US6509840B2/en
Application filed by Gelcore LLC filed Critical Gelcore LLC
Publication of EP1352544A2 publication Critical patent/EP1352544A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G02B5/1876—Diffractive Fresnel lenses; Zone plates; Kinoforms
    • 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
    • F21V17/00—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages
    • F21V17/10—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages characterised by specific fastening means or way of fastening
    • F21V17/16—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages characterised by specific fastening means or way of fastening by deformation of parts; Snap action mounting
    • F21V17/164—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages characterised by specific fastening means or way of fastening by deformation of parts; Snap action mounting the parts being subjected to bending, e.g. snap joints
    • 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
    • F21V31/00—Gas-tight or water-tight arrangements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
    • G02B19/0004—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed
    • G02B19/0028—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed refractive and reflective surfaces, e.g. non-imaging catadioptric systems
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
    • G02B19/0033—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use
    • G02B19/0047—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source
    • G02B19/0061—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source the light source comprising a LED
    • G02B19/0066—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source the light source comprising a LED in the form of an LED array
    • 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
    • F21V23/00—Arrangement of electric circuit elements in or on lighting devices
    • F21V23/04—Arrangement of electric circuit elements in or on lighting devices the elements being switches
    • F21V23/0442—Arrangement of electric circuit elements in or on lighting devices the elements being switches activated by means of a sensor, e.g. motion or photodetectors
    • 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
    • F21V31/00—Gas-tight or water-tight arrangements
    • F21V31/005—Sealing arrangements therefor
    • 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
    • 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

Definitions

  • the present invention relates to signals, in particular, Light Emitting Diode (LED) Signals. More specifically, the present invention relates to an LED traffic signal that is less susceptible to the "sun phantom" effect, having an improved viewing aspect and a LED light output degradation sensing circuit and light pipe collector, as well as materials, manufacturing and installation cost advantages.
  • LED Light Emitting Diode
  • LED traffic signals present numerous advantages over common incandescent lamp traffic signals. Use of LED's provides a power consumption savings and extremely long life in comparison to common incandescent light sources. The long life span creates improved reliability and sharply lowered maintenance costs.
  • LED's are used as an individual LED is not bright enough to equal the light output of an incandescent lamp.
  • multiple LED's created a display aspect with multiple individual points of light readily discernible by the viewer.
  • a non-uniform display aspect is commercially undesirable for traffic signals.
  • One method of preventing discernable individual light points has been to use a full array of LED's. However this is not commercially competitive as each additional LED is a significant percentage of the signals total cost.
  • Each generation of LED's is becoming brighter and brighter requiring fewer and fewer LEDs to equal the light output of an incandescent lamp but at the same time increasing the likelihood that the individual point sources and/or shadows between each LED are then detectable by the viewer.
  • Common LEDs include a semiconductor diode pellet located above a cup shaped reflector incased in a barrel shaped epoxy housing with a lens formed in its top.
  • the LED lens and the reflector cooperate to direct approximately 65% of the light emitted by the diode through the lens shaped top end in a vertically directed wide conical light distribution pattern.
  • the remaining 35% of light emitted by the diode is unusable as it is radiated at angles ranging between just outside of the forward conical light distribution pattern and horizontally through the sides of the LED housing.
  • Attempts to recover and utilize the horizontally radiated light have included mirrored reflectors and/or mirrored optical receiving bodies with mirror coatings on their outside surfaces, thereby creating a parabolic reflector that captures and redirects the horizontal light.
  • Total internal reflection is a phenomenon where electromagnetic radiation (light) in a given medium (for example acrylic or polycarbonate material) incident on the boundary with a less dense medium (for example air), at an angle equal to or larger than the critical angle, is completely reflected from the boundary.
  • a given medium for example acrylic or polycarbonate material
  • a less dense medium for example air
  • Total internal reflection is described in detail in "Modern Optical Engineering” Library of Congress Catalog Card Number 66-18214, hereby incorporated by reference. Applicant is unaware of previous application of total internal reflection as a means for collecting and redirecting horizontal light "lost" from a common LED.
  • LED traffic signals Due to the large installed base, worldwide, of incandescent traffic signal systems, most LED traffic signals are designed to be retro-fitted into existing traffic signal systems originally designed for incandescent lamps.
  • signal assemblies incorporate a power supply to drive LED's at a lower, controlled, direct current power level.
  • this has resulted in an LED traffic signal assembly with a separate power supply built on a Printed Circuit Board (PCB) and a separate LED matrix PCB connected via wiring between the two PCB's as well as spliced into the original incandescent power wiring. Integration of LEDs onto a single PCB including the power supply results in a smaller PCB with corresponding manufacturing and cost of materials benefits.
  • PCB Printed Circuit Board
  • Traffic signals are susceptible to "sun phantom" phenomena.
  • a light source for example the sun
  • shines upon the face of a traffic signal a bright spot, or worse, internal reflection from within the signal, may make it appear to a viewer that the signal is energized when, in fact, it is not, leading to an increased chance for accidents.
  • Previous LED signal lamps are especially susceptible to "sun phantom” phenomena because the rear surface of each LED is highly reflective.
  • Previous LED signal designs located the LED's on or close to the outer surface where the rear surface of each LED could easily be reached by stray light, creating an increased opportunity for "sun phantom” reflections.
  • Previous LED signals that use a secondary optical element between the LED's and the outer cover also suffer from sun phantom effect as the stray light reflects back, generally along the center axis, rather than towards the ground, off of the optical element.
  • LED signals have an extremely long service life that has increased with each new generation of LEDs. Incandescent lamps, while having a much shorter service life, have relatively constant light output until a total failure occurs, i.e. burnout of the light filament. LED signals, over an extended period, have gradually diminishing light output. Further, LED light output is negatively affected by temperature. In extreme climate or during unnaturally warm periods LED light output diminishes during the day and then returns to a normal level during cooler periods at night.
  • the present invention has the following objectives:
  • An LED signal which presents a uniform brightness display aspect equal to or better than a common incandescent lamp traffic signal.
  • An LED signal comprised of a single printed circuit board carrying both the LED's and the power supply components.
  • An LED signal capable of easy upgrade to higher output LEDs without requiring recalculation of the optical elements.
  • An LED signal usable in multiple configurations, each specific to a given application, with a minimum of unique components being required.
  • a cost efficient apparatus for capturing and utilizing horizontal light emissions from common LEDs 9.
  • a cost efficient apparatus for creating a controlled light emission pattern with minimal optical materials cost 11.
  • Placement of the LEDs, to create an overlapping light emission pattern at an increased distance from a Multiple Collimating Zone Element (MCZE) creates a uniform display aspect for the signal, without individual points of light.
  • the increased distance also allows placement of power supply components and circuitry on a single PCB with the LEDs, spaced so as to prevent interference with the LED light.
  • a light pipe collector (LPC) for LED signals captures and redirects normally unutilized horizontally emitted LED light. Designed for total internal reflection, the LPC redirects horizontally emitted light without the use of mirrored surfaces or reflective coatings.
  • a single LPC may be snap fit to the PCB over a group of several LEDs. As the light output of LEDs increases with each new generation the same LPC may be used with fewer LEDs without requiring redesign and/or remanufacture.
  • the LPC When designed with a side to side dimension in close tolerance with the external dimension of the LEDs, the LPC also assists in properly orienting LEDs that may be misaligned due to imperfections in the LEDs housings or poor assembly.
  • the LPC may be designed to provide an optical solution that eliminates or minimizes the need for additional optics in the LED signal. Formed into directional arrows or letters the LPC creates an LED signal with a minimal number of LEDs without requiring other optics.
  • the LPC creates an LED signal with materials, manufacturing and operating cost efficiencies previously unavailable.
  • the "sun phantom" phenomena is prevented by a large radius spherical outer distribution cover, angled to reflect stray light away from the viewer, towards the ground.
  • a complex inner surface on the distribution cover creates a shaped light distribution, focused upon the viewer, while at the same time further directing stray light reflections, again, towards the ground.
  • a light sensor mounted within an LED signal housing senses the LED light output level. When the light level falls below a preset level, a short circuit is created that breaks a fusible link on the input power line. The broken fusible link disables the LED signal thereby alerting users that replacement is necessary.
  • Figure 1 is a side view of a common 5mm LED showing a typical light output distribution.
  • Figure 2 is a side view of a common LED with a LPC redirecting the light into a forward direction.
  • Figure 3 is another embodiment of a light pipe showing Figure 2. This embodiment does not have a dome lens directly above the LED.
  • Figure 4 is an isometric schematic view of a set of linear and curved LPCs.
  • Figure 5 shows the LPCs of Figure 4 in matching orientation with an MCZE.
  • Figure 6 is a partial isometric schematic view of a LPC viewed from below showing LED's within the channel.
  • Figure 7 is an isometric schematic view showing alternate LED distributions within a LPC.
  • Figure 8a is a schematic view of a LPC configured for a cluster of one or more LED's.
  • Figure 8b is a side view of the LPC of Figure 8a.
  • Figure 9a is an isometric schematic view from below of a LPC for a cluster of 4 LED's.
  • Figure 9b is an alternate embodiment of the LPC of Figure 9a for 7 LED's.
  • Figure 10a is an isometric schematic view, from above, of a LPC configured as a directional signal.
  • Figure 10b is an isometric schematic view of the LPC of Figure 10a, from below, showing the location of the LEDs.
  • Figure 11 is an exploded view showing the various components of an LED signal.
  • Figure 12 is an electrical schematic showing the automatic light-degradation sensor control circuit.
  • Figure 13 is an electrical schematic showing the automatic light degradation sensor circuit including the LED signal, AC power connections and a fusible link for disabling the
  • Figure 14 is an exploded view showing the major components of a circular MCZE embodiment of the invention.
  • Figure 15 is a diagram showing possible light distribution and intensity for circular, horizontal and vertical embodiments of the MCZE.
  • Figure 16 is a close-up view of the o-ring sealing means and connection tab into tab socket connection means.
  • Figure 17 is a cut-away side view of the 12" embodiment of the invention (electrical and interior components omitted for clarity), showing a ray diagram between the LED's and the distribution cover and an example of the distribution covers optical effect.
  • Figure 18 is a diagram demonstrating the "sun phantom" effect.
  • Figure 19 is a view of a typical traffic signal housing, showing retrofitting of the present invention, replacing the original outer lens and incandescent lamp.
  • Figure 20 shows a cut-away view of an 8" embodiment of the invention (power supply components omitted for clarity) .
  • Figure 21 is a three dimensional view of the backside of the distribution cover. Detailing the compound optical correction surfaces.
  • Figure 22 is a close-up three-dimensional view of a portion of the optical correction surfaces shown in figure 21.
  • Figure 23A is a diagram showing common light refraction/reflection.
  • Figure 23B is a diagram showing total internal reflection.
  • Figure 24 is a schematic view of a baffle, shroud or blinder for the light sensor.
  • Figure 25 is another embodiment of the baffle, shroud or blinder of Figure 24.
  • Figure 26 is another embodiment of the baffle, shroud or blinder of Figure 24.
  • Figure 27 is another embodiment of the baffle, shroud or blinder of Figure 24.
  • a common 5mm barrel shaped LED 1 has a diode semiconductor pellet 8 positioned in an epoxy housing 2 between a lens/dome 10 and a cup shaped reflector 4 formed ' at the end of one of two electrical leads 6.
  • the cup shaped reflector 4 and lens/dome 10 cooperate to direct approximately 65% of the LED's light output into a wide conical shaped distribution pattern in the vertical direction.
  • the remaining 35% of the LED's light is unusable, radiated 360° at angles ranging from just outside the wide conical shaped distribution pattern and in a generally horizontal direction.
  • An LPC 15, as shown in Figures 2 and 3, may be used to maximize the utilization of all light emitted by the LED 1.
  • the LPC made of a transparent or colored plastic, acrylic or polycarbonate material is designed to use total internal reflection to reflect light emitted by the LED 1 in the horizontal direction into the vertical direction.
  • an incident ray at an angle teta to the normal passing from a higher index of refraction medium creates a refracted ray at an angle teta " to the normal and a reflected ray at an angle teta to the normal.
  • polycarbonate material has an index of refraction of 1.59.
  • the reflection surface 12 is designed to be at a critical angle of 38.9° or more with respect to the incident ray emitted by the light source (diode semiconductor pellet 8) and the outer surface of the reflection surface 12 is surrounded by air, or other medium less dense than air, total internal reflection will occur. Total internal reflection removes any requirement that the reflector surfaces be mirror coated, reducing manufacturing costs.
  • the recovery of unused light by the LPC 15 allows fewer LEDS 1 to be used to create the same amount of signal light output.
  • the LPC 15 pays for its added materials cost by eliminating LEDs 1 otherwise required. Using fewer LED's 1 reduces the operating energy consumption of the LED signal.
  • the LPC 15 can be designed to spread and/or focus the light.
  • an optical dome 20 may be used to redirect the LED's main light output.
  • the dome 20 assists in creation of a narrower, well defined, light emission pattern useful for associating a specific LED or group of LEDs with a specific collimating zone or other optical element having a specific amount of overlap with neighboring colimating zones or other optical elements.
  • the LPC 15 may be designed for use with a single LED 1 as shown in Figures 8a and 8b. However, depending on the light requirements of the LED signals specific application and the light available from an individual LED 1, multiple LEDs 1 may be required.
  • Figure 6 shows an LPC 15 designed to fit over multiple LEDs arranged in a linear configuration.
  • a receiving chamber 14 in a slot configuration is sized to accept the LEDs 1 along its length.
  • the receiving chamber 14 also acts to align the LEDs, aligning them in a common orientation despite errors in LED placement with respect to the PCB, extra housing epoxy on the leads ' 6 or other alignment errors.
  • Properly oriented LEDs, directing the light as intended by the LED signal's optical design solution creates a bright and uniform display aspect for the signal.
  • an LPC 15 for multiple LEDs can be used without modification with each new generation of LEDs or across different LED signal models, requiring different light output levels, by modifying the number and distribution of the LEDs within the receiving chamber 14, as shown in Figure 7.
  • the LPC 15 is designed to surround a cluster of LEDs 1.
  • the distribution of the LEDs within the receiving chamber 14 can also be modified as LEDs improve or as the light intensity level of the specific application demands.
  • the LPC 15 are distributed across the PCB, following the LED 1 placement.
  • the LPCs can be configured to follow multiple LEDs in a linear or arched configuration, as shown in Figure 4, the overall layout matching other optical elements, for example as shown in Figure 5.
  • the LPCs may be used to create directional or informational symbols, letters or pictograms, for example as shown in Figure 10a and 10b. This embodiment is especially useful when designed as a complete optical system with only an outer mask/cover.
  • LPCs of all types may be connected to the PCB via connection means such as bayonet type pass through snap connectors 25. This type of connection is quick to assemble and requires no additional fasteners or special tools.
  • a housing 50 holds the components of the traffic signal.
  • the housing 50 may be formed from, for example, polycarbonite material. Polycarbonite material having excellent strength and impact resistance characteristics.
  • Formed into the base of the housing 50 are metal power terminals 62.
  • the metal power terminals 62 have exposed threaded posts on the internal side upon which a power connector spacer 64 may be attached.
  • the PCB 28 is attached to the power connector spacer 64 with screws.
  • the PCB 28 has mounted upon it a pattern of LEDs 1. In this embodiment the LEDs 1 are arranged in horizontal rows and arcs. Between the rows are arranged the power supply components 24.
  • the power supply components 24 are arranged in a way that minimizes the interference with the light emitted from the LEDs 1.
  • the PCB 28 fits into the housing 50 via mounting posts 29 and is fixed in place with screws. To allow as large a PCB 28 as possible, thereby allowing a larger distribution of LEDs 1, the PCB 28 is angled within the housing 50.
  • the mounting posts 29 orient the PCB 28, precisely aligning the LEDs 1 of the PCB 28 with respect to the MCZE 30 into parallel planes.
  • the MCZE 30 is oriented with respect to the housing 50 by placement upon the top surface of the housing 50 upon which it is retained by mounting posts on the housing 50 and distribution cover 32.
  • the MCZE 30 may also be formed in, for example, a circular, or horizontal/vertical linear configuration.
  • An embodiment with a circular MCZE 30 is shown in Figure 14.
  • the PCB 28 is alternatively powered via a power connector cable 67 which connects to a power connector board 64, mounted on the metal power terminals 62 using nuts 16.
  • the different MCZE configurations (circular, vertical and horizontal) result in different light distribution patterns with corresponding spatial intensities of the collimated light exiting the MCZE.
  • Use of fringe optical corrections and combinations of linear with circular and or arcs creates a light distribution tailored to a specific application.
  • a different MCZE configuration and matching PCB layout may be selected .
  • a railroad application may use a vertical linear MCZE as the required horizontal viewing aspect is very narrow (generally the train track width), while the wide vertical aspect allows viewing of the signal from a wide vertical range, corresponding to viewing locations near and far from the signal at either track or train cab level.
  • an automobile traffic signal may be designed with a majority of horizontal linear zones in the MCZE to have a wide spread horizontally, across many lanes of traffic.
  • Final tuning of the light distribution is made by the distribution cover 32.
  • Ray tracing computer software allows calculation of very specific optical solutions for the MCZE 30, LCP 15 and distribution cover 32. Where the LCP 15, alone, creates an acceptable light distribution and or uniform display aspect, the MCZE 30 may be omitted.
  • connection tabs 34 arranged around the periphery of distribution cover 32, fit into tab sockets 36.
  • Tab socket keys 38 located proximate the tab sockets 36 lock the connection tabs 34 in place upon insertion.
  • the mating point between the tab socket key 38 and a corresponding hole 35 in the connection tab 34 is arranged and configured to retain the distribution cover 32 at the location where the DC foot 42 bottoms against the housing 50.
  • One connection tab 34 and corresponding tab socket 36 are slightly wider than the others, thereby allowing assembly of the distribution cover 32 and housing 10 in only a single, proper, orientation.
  • a dust and water resistant seal is provided by o-ring 40.
  • the o-ring 40 preferably made of EPDM material, is sized to elastically fit upon housing shoulder 44.
  • Distribution cover 32 has a primary radius 48 which allows the distribution cover 32 and housing 10 to be initially loosely fitted together, aligned by the connection tabs 34 fitting into tab sockets 36.
  • a final snap fit bottoms DC foot 42 against the housing 50 engages the tab socket keys 38 to the corresponding holes 35 in connection tabs 34 and seats o-ring 40 between housing shoulder 44 and cover shoulder 46.
  • the o-ring 40 provides a shock dissipation function for impacts upon the distribution cover during use.
  • Power may be supplied to the traffic signal via main power wires 43.
  • the main power wires 43 having the ends stripped to expose the bare conductor, fit into holes in the outside surface of the power terminals 62.
  • the fit of the main power wires 43 into the power terminals 62 is loose.
  • Electrical contact between the main power wires 43 and power terminals 62 is insured by the use of main power connector covers 45.
  • With the main power wires 43 inserted into the power terminals 62 the main power connector covers 45 are friction fit into the holes thereby retaining the main power wires 43 in electrical contact with power terminals 62.
  • the main power connector covers 45 have a cover extending along the main power wires 43 in the down direction, thereby shedding any moisture which may collect or be moving across the back of the housing 50.
  • the main power wires as shown in figure 11, may connect to a standard incandescent lamp socket using an incandescent lamp socket plug 55.
  • the calculation of the pattern of the MCZE 30, preferably made of acrylic material, with respect to the PCB 28 and the location of the LEDs 1 thereon is very precise. Taking into account the constraints of the size of the housing 50, allowing it to fit within existing signal openings, the distance between the PCB 28 and the MCZE 30 is made as large as possible. Then, taking into account the angle of usable light emitted from the LEDs 1 and LCP 15 if present, a pattern of LEDs in concentric circles, arcs and or linear rows is formed on the PCB 28 to cover the surface of the MCZE 30 fully with LED light.
  • the MCZE 30 has multiple circular or linear collimating zones arranged matching the concentric circles or linear rows of LEDs 1 on the PCB 28.
  • Each circular or linear collimating zone collimates the light emanating from its respective LED 1 and or LCP 15 arc, ring or linear rows.
  • the LED light patterns slightly overlap within and between the rings or rows thus preventing the appearance of shadows, lines, or rings. Due to the overlap, individual LED 1 failure, or variation in LED 1 output between adjacent LEDs 1 will be minimally discernable by the viewer, if at all.
  • fringe elements collect spurious light from within the housing and collimate it in a forward direction.
  • the end result of the combination of the PCB 28 having LEDs 1 and or LCP 15 and matching patterned collimating elements of the MCZE 30 is to produce a full pattern of collimated light emitted from the MCZE 30 without gaps discernable to the viewer.
  • the collimated light from the MCZE 30 passes next to the distribution cover 32.
  • LCP's 15 are used without an MCZE 30, the light emitted by the LCP 15 passes directly to the distribution cover 32.
  • the distribution cover 32 has a further pattern on its inside surface, shown in Figures 21 and 22 which directs the collimated light into a final distribution pattern optimized for viewing at the normal design distance and angle from the front of the signal.
  • the present invention uses a large radius (more than 24" radius for the 12" embodiment and more than 18" radius for the 8" embodiment) outer surface of the distribution cover 32.
  • the large radius simplifies the optical solution for the pattern on the back of the distribution cover.
  • the outer surface of the distribution cover 32 is aligned at an angle inclined towards the ground . As shown by figure 18, this has the effect as compared to a conventional forward facing small radius spherical lens traffic signal of reflecting any sun light or other light source towards the ground rather than back towards the viewing position intended for the signal.
  • a problem of LED signals in the past has been external light sources reflecting into the signal encountering the LEDs which have a highly reflective back surface, creating a noticeable "sun phantom" effect.
  • the increased distance between the LEDs 1 and the outer surface of the distribution cover 32 minimizes the chance for internal reflection resulting in a "sun phantom" effect.
  • the back face of distribution cover 32 is designed to again direct any external light source to the ground rather than back to the intended viewing position of the traffic signal.
  • the present invention may be easily retrofitted into an existing traffic signal upon removal of the original outer lens and incandescent lamp.
  • the housing outer rim 47 may be designed to have the same thickness as the lens it replaces. Power connection of the retrofitted light may be performed, without requiring an electrician, by simply screwing the incandescent lamp socket plug 55 into the original incandescent lamp socket.
  • the invention is adapted to fit in an existing 8" incandescent traffic signal upon removal only of the incandescent bulb and outer lenses.
  • the PCB 28 is not angled and therefore direct connection to power terminals 62 can be made without use of a separate power connector board 66 and power connector cable 67 or power connector spacer 64.
  • the MCZE 30 and inner surface of the distribution cover 32 are optimized for the different LED 26 layout and angles of the PCB 28 and MCZE 30 with respect to the distribution cover 32.
  • the above invention is optimized for presently available cost effective LED's 1. As higher output, cost effective LED's become available, fewer LED's 1 will be required to obtain the same light output. Due to the overlapping output of the present LEDs, when higher output LEDs become available, modification of only the LED spacing on the PCB is required. LCP's, if present, may be designed to allow the LED spacing within the receiving chamber 14 to be varied without requiring redesign of the LCP.
  • the distribution cover is independent of the light source as it receives an even distribution of collimated light from the MCZE for final distribution to the viewer.
  • a light sensor PHI is mounted on the PCB 28.
  • the light sensor PHI may be, for example, a photo diode, a photo transistor, a photo cell or other device capable of outputting a signal with respect to the light level sensed.
  • Light sensor PHI is an input for a comparator circuit which compares the input to a reference voltage. If the input does not exceed the preset level, a short circuit is created between the AC power and AC neutral input lines which burns out a fusible link placed at the power input to the PCB 28, deactivating the signal.
  • the light sensor PHI is a photo transistor, a common voltage comparator circuit may be used.
  • the reference voltage set by selection of the resistor in the voltage comparator circuit, determines the light level at which the fusible link will be burnt out.
  • the short circuit may be created by, for example, a mosfet switch.
  • FIG. 12 A specific example of the electrical circuitry is shown in Figures 12 and 13.
  • the switching portion of the light degradation sensor circuit is shown in Figure 12.
  • Light sensed by a photo transistor PHI creates a proportional current output which, transformed by resistor R17 and filtered by capacitor Cll is seen as a voltage level input to the REF pin of comparator integrated circuit Ul, for example a TL431 adjustable precision shunt regulator.
  • the selected value of resistor R17 sets the voltage level proportional to the desired light level which the comparator circuit Ul will compare to its internal reference voltage. As the LED light output degrades over time, PHI senses less and less light, lowering its output.
  • FIG 13 shows the interaction of the switching portion of the light degradation sensor circuit, shown in Figure 12, with the power input to the LED signal.
  • Fuse 2 has an approximate rating of 250 mA. High current levels created by the short circuit quickly blows Fuse 2.
  • Fuse 1 having a rating of approximately 4-5 amps is used for protecting against problems in the power supply lines ACl and AC2. If a voltage spike occurs in the supply lines a metal oxide varistor MOV shorts the lines, protecting the LED signals electronics. Placement of the metal oxide varistor between Fuse 1 and Fuse 2 prevents line transients from falsely blowing the low current rated Fuse 2.
  • Fuse 2 is directly soldered onto the PCB 28, preventing easy replacement or bypassing of the fuse after it has been blown. This feature frustrates "repair” and continued use of the LED signal after the LED light output has degraded below the design level.
  • shroud or blinder 27 as shown in Figures 24-27 may be used so that the light sensed is a reflection off of the optical elements and/or the housing side walls and not dependent just on the output of the closest LED(s) 1.
  • the light sensor is in operation whenever the LED signal is energized.
  • external light levels may influence the light sensor PHI into a false reading that LED 1 output levels are normal even though they have in actuality degraded below the acceptable level. This is not a problem as the degradation in output levels occurs over a period of years.
  • a difference of an additional 12 hours for nighttime or other transient interruption of the external light to occur) is immaterial. This also prevents a temporary output degradation due to extreme heat from triggering a fuse blow out.
  • a capacitor, resistor combination or other timed delay can be used to create a known delay period during which the input must be below the reference level or the circuit will reset and be forced to pass through the entire delay period again before triggering the fuse blowing short circuit. This feature prevents line voltage transients that may temporarily lower light output or create a false output at the mosfet Q4 from triggering the fuse blowout.
  • a family of signal devices may be created from the present invention using common components. Different distribution covers, creating different distribution patterns may be snap fitted onto a common housing with standardized PCB and MCZE. Information and/or directional signals may be created by masking portions of the distribution cover into, for example, turn signal arrows.
  • a variation of the housing, using otherwise similar components may be used to create efficient stand alone signals or even general illumination light sources useful, for example, when it is foreseen that the light source will be located where maintenance will be difficult and an extreme service interval is desired .

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Traffic Control Systems (AREA)
  • Geophysics And Detection Of Objects (AREA)

Abstract

L'invention concerne une signalisation à diodes électroluminescentes, dotée d'un collecteur à conduite de lumière à diodes électroluminescentes et d'un capteur intelligent de dégradation de lumière. Le collecteur à conduite de lumière capture une lumière de diodes électroluminescentes normalement perdue dans un sens généralement horizontal et la redirige dans un sens généralement vertical au moyen d'une réflexion interne totale. Le capteur de dégradation de lumière surveille la sortie de lumière de la signalisation à d'iodes électroluminescentes. Lorsqu'une sortie de lumière est dégradée à un niveau prédéfini, un circuit électrique déclenche un court-circuit de désactivation permettant de désactiver la signalisation à diodes électroluminescentes.
EP01273916A 2001-01-09 2001-12-18 Signalisation a diodes electroluminescentes permettant de detecter une degradation de lumiere, dotee d'un collecteur a conduite de lumiere Withdrawn EP1352544A2 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US756670 1996-11-26
US09/756,670 US6509840B2 (en) 2001-01-10 2001-01-10 Sun phantom led traffic signal
US09/827,429 US6717526B2 (en) 2001-01-10 2001-04-06 Light degradation sensing LED signal with light pipe collector
US827429 2001-04-06
PCT/IB2001/002890 WO2002071812A2 (fr) 2001-01-09 2001-12-18 Signalisation a diodes electroluminescentes permettant de detecter une degradation de lumiere, dotee d'un collecteur a conduite de lumiere

Publications (1)

Publication Number Publication Date
EP1352544A2 true EP1352544A2 (fr) 2003-10-15

Family

ID=27116272

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01273916A Withdrawn EP1352544A2 (fr) 2001-01-09 2001-12-18 Signalisation a diodes electroluminescentes permettant de detecter une degradation de lumiere, dotee d'un collecteur a conduite de lumiere

Country Status (4)

Country Link
EP (1) EP1352544A2 (fr)
AU (1) AU2001297694A1 (fr)
CA (1) CA2434724A1 (fr)
WO (1) WO2002071812A2 (fr)

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EP2539877B1 (fr) * 2010-02-24 2017-08-30 Siemens Aktiengesellschaft Indicateur de symbole

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DE102008017613B4 (de) 2008-04-04 2010-12-16 Insta Elektro Gmbh Leuchtbaugruppe
US8089374B2 (en) * 2008-11-18 2012-01-03 GE Lighting Solutions, LLC LED signal light
KR20100073806A (ko) 2008-12-23 2010-07-01 삼성전자주식회사 콜리메이트 렌즈 조립체
US8465190B2 (en) * 2009-05-22 2013-06-18 Sylvan R. Shemitz Designs Incorporated Total internal reflective (TIR) optic light assembly
DE102010009432A1 (de) * 2010-02-24 2011-08-25 Siemens Aktiengesellschaft, 80333 Symbolanzeiger
PL2550649T3 (pl) 2010-03-24 2014-09-30 Siemens Ag Optyczny element wyświetlający i urządzenie wyświetlające
SE535601C2 (sv) * 2011-02-24 2012-10-09 Nordic Light Ab Fästanordning och belysningssystem
WO2020184695A1 (fr) * 2019-03-14 2020-09-17 株式会社アイテックシステム Système d'irradiation de lumière

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US6019493A (en) * 1998-03-13 2000-02-01 Kuo; Jeffrey High efficiency light for use in a traffic signal light, using LED's
DE59911260D1 (de) * 1998-07-23 2005-01-20 Siemens Ag Lichtsignalanlage sowie Verfahren zum Überwachen der Lichtsignalanlage

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EP2539877B1 (fr) * 2010-02-24 2017-08-30 Siemens Aktiengesellschaft Indicateur de symbole

Also Published As

Publication number Publication date
CA2434724A1 (fr) 2002-09-12
WO2002071812A3 (fr) 2003-01-03
WO2002071812A2 (fr) 2002-09-12
AU2001297694A1 (en) 2002-09-19

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