EP2488401B2

EP2488401B2 - Led-type luminous signaling device and relative control method

Info

Publication number: EP2488401B2
Application number: EP10798582.2A
Authority: EP
Inventors: Edoardo Ecoretti
Original assignee: SOLARI DI UDINE SpA
Current assignee: SOLARI DI UDINE SpA
Priority date: 2009-10-16
Filing date: 2010-10-15
Publication date: 2017-07-12
Anticipated expiration: 2030-10-15
Also published as: WO2011045663A1; IT1396088B1; ITUD20090184A1; EP2488401B1; EP2488401A1

Description

FIELD OF THE INVENTION

The present invention concerns a LED-type luminous signaling device used, for example but not only, in traffic-light apparatuses.
In particular, the luminous signaling device according to the present invention is preferentially used in traffic-light apparatuses to regulate rail or road traffic, whether driven manually or automatically.
Here and hereafter in the description, as a non-restrictive example, we will refer specifically to traffic-light apparatuses used in railroad applications, but it cannot be excluded that the luminous signaling device according to the present invention can also be applied to other types of signaling apparatuses, such as signaling buoys, signaling devices for electric pylons or cables, or public lighting devices.
More generally, and without constituting a limitation, the device according to the invention is applied in cases where it is desired to guarantee a great safety in the correct functioning of luminous signaling systems, in order to prevent accidents or dangerous situations for persons or things.
EP-A-1.215.641 discloses a LED-type luminous signaling device comprising LED-type luminous emission sources with optical feedback.
WO2006099732A1 discloses the features of the preamble of main claim 1.

BACKGROUND OF THE INVENTION

On the railways, in order to guarantee a correct functioning of traffic-light apparatuses, that is, to ensure adequate diagnostics that will signal possible anomalies in functioning, it is known to associate with the electric lines that feed the lamps a device to detect the current that is actually absorbed.
This allows to detect, in the event of a partial or total breakage of the lamp, that the expected value of electronic current has not been absorbed, and therefore to signal said malfunction to the operators responsible for supervising the rail traffic. In this way it is possible to act quickly, for example by modifying the current state of rail traffic, warning the personnel driving the trains and the operators responsible for maintenance of the rail network in order to carry out the appropriate operations.
Moreover, in numerous fields of application, it is more and more frequent to use LED-type luminous elements both because the light emitted is more direct and coherent, and also because they last longer and have lower electric consumption, given the same light emitted, compared with traditional lamps. Another advantage of LED-type luminous elements is that given by their nature as multi-point emitter, so that they can continue to carry out their function even when there is a breakage and/or malfunction in some of the elements.
Since this is an innovative technology, it is only recently that such LED-type luminous elements have been applied in traffic-light apparatuses on the railways or suchlike.
Since it is more complex than the filament of a bulb, LED technology has a lot of cases of breakdowns, for example an open LED, a shortcircuited LED, low light emission, or others.
This entails a real difficulty in guaranteeing high reliability of the functioning diagnostics, which is, however, indispensable in such types of luminous signaling applications.
Indeed it is practically impossible to identify with certainty all the possible conditions of breakage or malfunctioning of LED-type elements based on the analysis or detection of electric quantities, such as current, tension, electric power absorbed.
Given their nature, it is extremely difficult to distinguish between a condition in which total or partial current is absorbed in order to understand if there are sufficient LED elements functioning to guarantee the correct functioning of the signaling device. It is also possible for a LED element that is not emitting luminous radiation to absorb current in any case, thus rendering it impossible to detect that it is broken, except by carrying out a visual inspection.
Furthermore, unlike the traditional incandescent bulb, LED technology, since it is multi-source, allows to keep the device in an operating state even in the event of one or more elementary LED sources not functioning. Indeed there are different techniques to guarantee full functioning even in poor conditions, such as for example the use of current shunt to the heads of broken LEDs, increasing the pilot current on LEDs that are still whole, or others. However, in this case too, as we said before, it is difficult to detect reliable diagnostic data based on the detection of the functioning electric quantities of the LEDs.
Purpose of the present invention is to achieve a LED-type luminous signaling device used preferably, but not only, in traffic-light apparatuses, which makes the functioning diagnostics reliable, detecting and signaling possible malfunctions, even partial, such as breakages or considerable reductions in the luminous radiation emitted.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.
According to a variant of the present invention, the LED-type luminous emission source or sources emit luminous radiation on the same wavelength.
According to a variant of the present invention the LED-type luminous emission sources are divided into two or more groups, uniformly distributed on a single support, each group being able to be alternately activated and suitable to emit luminous radiation at a determinate wavelength. In this way, by selectively controlling the activation of each group of LED-type luminous emission sources it is possible to emit a luminous radiation of the desired color, for example red, amber or green, or to provide that all the LED-type luminous emission sources are the same color, thus being able to activate the groups alternately, allowing to increase the operating duration of the device.
According to a variant of the present invention, the signaling device comprises control and processing means, connected to the optical detection means, to acquire the detection data and to calculate the quantity of luminous radiation emitted over all.
According to another variant, the device comprises an electric load, or fictitious load, able to be selectively activated according to the detection of the quantity of light emitted over all and detected by the optical detection means. In this way, by switching said electric load on or off, according to the real functioning state of the device, it is possible to signal a functioning anomaly that can be detected remotely as if the signaling device were actually provided with a traditional lamp.
According to another variant of the present invention, the one or more light-directing lenses comprise darkening portions, suitable to absorb incident light from outside the signaling device. In this way it is possible to prevent detection errors by the detectors, produced for example by a high level of incident ambient light on the light-directing lens or lenses.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the present invention will become apparent from the following description of a preferential form of embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

fig. 1 is a view from above of a LED-type luminous signaling device according to the present invention;
fig. 2 is a perspective schematic view of a detail of the device in fig. 1;
fig. 3 is an enlarged lateral schematic view of a detail of fig. 2;
fig. 3A is an enlarged view of a detail in fig. 3;
fig. 3B is a view from above of fig. 3A ;
fig. 4 is a functional block diagram of the device in fig. 1.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify common elements that are identical in the drawings. It is understood that elements and characteristics of one form of embodiment can conveniently be incorporated in other forms of embodiment without any further clarifications.

DETAILED DESCRIPTION OF A PREFERENTIAL FORM OF EMBODIMENT

With reference to the attached drawings, a LED-type luminous signaling device 10 according to the present invention is advantageously used in a traffic-light apparatus, not shown in the drawings, used for example to regulate rail traffic.
The device 10 comprises a support 12, provided with a plurality of light-directing lenses 14 made in a single piece with the support 12. The support 12 is made by molding in plastic or polymer material, for example polycarbonate. The support 12 is stably coupled with an electronic card 13, or PCB (Printed Circuit Board), on which a plurality of LED-type luminous sources 16 are mounted, each associated with a corresponding light-directing lens 14, and a plurality of photo-detectors 17.
The support 12 and the electronic card 13 are similar in shape, in this case substantially circular, able to allow them to be stably inserted in a containing structure of the traffic-light apparatus. The LED-type luminous sources 16 are mounted on the electronic card 13, in a predetermined disposition consistent with the disposition of the light-directing lenses 14 on the support 12, so as to define an effective area of light emission, substantially concentrated in correspondence with the light-directing lenses 14.
In particular, the light-directing lenses 14 comprise a collimation portion 22 (fig. 3), disposed below the lens 14 and suitable to collimate in a single direction, or signaling direction, the luminous radiations emitted by an associated LED-type luminous source 16 in different directions. In this case the signaling direction is perpendicular to the plane identified both by the electronic card 13 and also by the upper surface of the support 12.
The light-directing lens 14 also comprises an exit portion 24, substantially flat, circular in shape, made on an upper face of the support 12. From the exit portion 24 the luminous radiations of the LED-type luminous sources 16 are emitted toward the outside in the signaling direction.
The light-directing lenses 14 are grouped together in modules 15 of three (fig. 2), in a regular disposition, in which the center of each light-directing lens 14 of the same module 15 is positioned in correspondence with the tops of an equilateral triangle and the corresponding exit portions 24 are reciprocally tangent in pairs. This modular disposition is repeated continuously and regularly over the whole support 12.
Each light-directing lens 14 of the same module 15 is associated with an underlying LED-type luminous source 16 of a different color. In this way, for each module 15, the corresponding triad of LED-type luminous sources 16 is able to be activated alternately, so as to switch them on one at a time, and thus to emit from the device 10 a luminous radiation of the desired color.
It is understood that the LED-type sources 16 can be the same type, that is, they can emit luminous radiation on the same wavelength, corresponding to a single color, in this case achieving a signaling device having a single signaling function, and in which all the LED-type sources 16 are activated simultaneously, or alternatively one LED-type source 16 at a time, so as to prolong the duration of operative functioning of the device 10.
At least some of the light-directing lenses 14, in correspondence with their exit portion 24, have an interception portion 18, able to divert a predefined fraction of light, that is, a known percentage of the total light emitted by each LED-type source 16. In particular, as shown in figs. 1 and 2, the interception portion 18 has a circular shape, common to the three light-directing lens 14 of the same module 15.
The interception portion 18 comprises an interception prism 19 (figs. 2 and 3) of the total reflection type, having an inclination of about 45 degrees with respect to the flat upper surfaces of the exit portion 24 and the interception portion 18, and a circular surface development. The interception prism 19 is suitable to intercept the predefined fraction of light emitted by the LED-type sources 16 associated with the module 15 and to reflect it in a direction substantially parallel to the flat surfaces of the interception portion 18 and the exit portion 24, that is, perpendicular to the signaling direction.
The length of the interception prism 19, and hence the thickness of the interception portion 18 with respect to the exit portion 24, is made both as a function of the wavelength of the luminous radiations emitted, and also as a function of the predefined fraction of luminous radiation to be intercepted.
According to a preferential embodiment, the predefined fraction of luminous radiation to be intercepted is around one per cent.
The interception portion 18 also comprises a reflection prism 20, again of the total reflection type, disposed in a central position with respect to the interception portion 18. The reflection prism 20 is suitable to reflect the fraction of luminous radiation intercepted by the interception portion 19 toward an area of the electronic card 13, central with respect to the three light-directing lenses 14, in correspondence with which area the associated photo-detector 17 is mounted. The reflection prism 20 is substantially shaped conical, with the lateral surface inclined by about 45 degrees with respect to the upper flat surface of the interception portion 18.
According to a variant, shown schematically in the block diagram in fig. 4, where only one photo-detector 17 and only one LED-type source 16 are shown, the signaling device 10 also comprises a processing and control unit 30, directly connected both to the photo-detectors 17 and also to the LED-type sources 16. The processing and control unit 30 is suitable to switch on the LED-type sources 16, based on a command received for example from remote, and also to acquire the data relating to the fraction of luminous radiation detected by the photo-detectors 17 and then to calculate the total luminous radiation emitted by the device 10.
The processing and control unit 30 can be a microprocessor of a known type, typically used in electronic devices.
Furthermore, in this solution, the device 10 comprises a fictitious electric load 32, connected to the control unit 30, able to be selectively driven by it according to the detection of total luminous radiation emitted by the device 10 and calculated by means of the detection of the corresponding fraction intercepted by the photo-detectors 17. The load 32 is switched on or off according to the real functioning state of the device 10, which allows to signal any functioning anomaly, for example detected remotely, as if the signaling device were actually provided with a traditional type lamp.
Advantageously some of the modules 15 of the device 10 are not provided with the interception portion 18, inasmuch as the light they emit is not sent in the signaling direction but is intercepted outside the device 10 by a front shield of the traffic-light apparatus, not shown. This light is diverted toward the bottom of the traffic-light apparatus so as to allow the operators responsible for maintenance to inspect the actual functioning state visually.
Advantageously, at least part of the support 12 comprises darkening portions 26, in which the plastic material is made opaque in correspondence with the spaces between the modules 15. This is to absorb the external light incident on the signaling device 10 and therefore to prevent external ambient luminous radiation being detected by the photo-detectors 17, which is not wanted.
The LED-type signaling device 10 as described heretofore functions as follows.
When the signaling device 10 is switched on, that is, when a first group of LED-type luminous sources 16 corresponding to the desired color is activated, a plurality of rays R' emitted by each LED-type source 16 in different directions is collimated by the collimation portion 22 into corresponding rays R" in the signaling direction. The rays R" are sent, inside the light-directing lens 14, toward the exit portion 24, striking it perpendicularly and coming out as rays emitted Re in the signaling direction.
A predetermined fraction of rays R', which after collimation inside the lens 14 is transformed into control rays Rc', incident on a part of the interception prism 19, is totally reflected by it and transformed into rays Rc" in a direction perpendicular to the signaling direction (figs. 3, 3A and 3B). The rays Rc" are propagated along the surface of the interception portion, substantially radially toward the center of the module 15 as far as the interception prism 20, in correspondence with which they are further reflected, totally, into corresponding control rays Rc"' toward the corresponding photo-detector 17 disposed on the electronic card 13.
The processing and control unit 30 acquires in a known manner the luminous radiation detected by each photo-detector 17, calculating the luminous radiation emitted overall by the device 10, according to the known and predefined percentage of the interception fractions of the interception prisms 19.
The detection of the luminous radiation captured by the photo-detectors 17 does not refer to an absolute emission value, but to a relative value corresponding to a stream of light specifically defined for each optical group. In fact, when the device 10 is inserted in a containing structure of the traffic-light apparatus, the calibration of the threshold level below which the malfunction is signaled allows to keep in consideration all the constructional variables of the signaling device 10, both mechanical and electrical, which can influence the stream of light actually emitted.
If from said calculation it emerges that the total light emitted by the device 10 is less than a predetermined functioning threshold, the device 10 activates an anomaly or breakdown signal, such as for example switching off the fictitious load 32, therefore allowing the remote detection of the functioning anomaly by a traffic control center.
It is understood that the signal can be done in a different way, for example by sending a message through a suitable communication network, by a wave conveyed on the electric feed line of the traffic-light apparatus.
It is clear that modifications and/or additions of parts and/or steps may be made to the LED-type luminous signaling device 10 and the relative control method as described heretofore, without departing from the field and scope of the present invention.
For example, it comes within the field of the present invention to provide that each module 15 is associated with a pair of photo-detectors 17, independent of each other, so as to guarantee a greater functioning reliability and detection efficiency.
It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of LED-type luminous signaling device and the relative control method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

Claims

LED-type luminous signaling device comprising LED-type luminous emission sources (16) and three light-directing lenses (14) able to diffuse the luminous radiation emitted by corresponding LED-type luminous emission sources (16) in at least one signaling direction,
the three light-directing lenses (14)
- being in a regular disposition, in which the centers of the light-directing lenses (14) are positioned at the vertices of an equilateral triangle, and

- comprising corresponding exit portions (24), from which the luminous radiation of the led-type luminous sources (16) are emitted toward the outside in the signaling direction, , and

- shaped so as to define at least an interception portion (18) suitable to divert a predefined fraction of total luminous radiation emitted by each LED-type luminous emission source (16) in one or more control directions, different from the signaling direction,
the signaling device further comprising
a support (12) provided with the light-directing lenses (14) made in a single piece with the support (12), and
a collimation portion (22), each being disposed below a respective light directing lens (14) and suitable to collimate in the signaling direction the luminous radiations emitted by an associated LED-type luminous source (16), and
optical detection means (17) disposed coherently with the control direction so as to detect said predefined fraction of luminous radiation diverted by the interception portion (18),
characterized by
the exit portions (24) being substantially flat, circular in shape, made on an upper face of the support (12) and being reciprocally tangent in pairs.
Device as in claim 1, characterized in that the LED-type emission source or sources (16) emit luminous radiation on the same wavelength.
Device as in claim 1 or 2, characterized in that the LED-type luminous emission sources (16) are divided into two or more groups, uniformly distributed on the support (12), each group being able to be alternately activated and suitable to emit luminous radiation on a predetermined wavelength.
Device as in any claim hereinbefore, characterized in that it comprises darkening portions (26) able to absorb incident luminous radiation from outside the device.
Device as in any claim hereinbefore, characterized in that it comprises control and processing means (30), connected to the optical detection means (17), and able to acquire the data from the optical detection means (17), in order to calculate the overall luminous radiation emitted.
Device as in any claim hereinbefore, characterized in that it comprises an electric load (32) able to be selectively activated according to the detection of the overall luminous radiation emitted and detected by the optical detection means (17).
Traffic-light apparatus used on the railways or roads comprising a LED-type signaling device (10) as in any claim from 1 to 6.