WO2009104067A1

WO2009104067A1 - Street lighting device with leds, and method to make the same

Info

Publication number: WO2009104067A1
Application number: PCT/IB2009/000273
Authority: WO
Inventors: Giuseppe Gregoris; Ivo Del Ben
Original assignee: LED GO Srl
Current assignee: LED GO Srl
Priority date: 2008-02-18
Filing date: 2009-02-16
Publication date: 2009-08-27
Anticipated expiration: 2010-08-18
Also published as: ITUD20080032A1

Abstract

Lighting device (10) and method comprising a support structure (13, 113) which supports one or more groups of LEDs (15) which emit relative light beams, to light a determinate surface (S). The device (10) also comprises one or more arms (16, 116, 216) disposed independent and individually directed or directable with respect to the support structure (13, 113) so that each supports at least one of the group of LEDs (15), and a plurality of optic members (21) each of which is associated at least with a relative one of the LEDS (15) and has a determinate degree of collimation, to direct in a specific and uniform manner the light emitted by the relative LED (15), in a determinate sector of the surface (S) to be illuminated.

Description

"STREET LIGHTING DEVICE WITH LEDS, AND METHOD TO MAKE

THE SAME"

*****

FIELD OF THE INVENTION The present invention refers to a street lighting device, such as for example a lamp, a streetlamp, a lamp post or the like, provided with a light source including LEDs (Light Emitting Diodes), to light a surface such as a road surface or more in general an urban or extra-urban area. In particular the lighting device according to the present invention is configured to light in a targeted and substantially uniform manner the road surface, or the surface to light, within a determinate field of action, normally called span.

BACKGROUND OF THE INVENTION

It is known that to carry out urban or extra-urban lighting, of streets, squares, gardens, parks, cycle tracks, flower beds or the like, devices such as lamps, street lamps, lamp posts or the like are normally used, which maintain a source of light suspended above a determinate surface to be illuminated.

Currently the majority of known lighting devices comprise a light source provided with one or more gas lamps or incandescent lamps,

This type of known lamp, in particular those using sodium gas, emit a light which tends toward yellow on the surface to be illuminated and they have high nominal energy consumption, and therefore high costs.

Moreover, the gas lamps normally used tend to lose their performance levels very quickly with use, determining a progressive increase in consumption and a reduction in their lighting potential. To reduce the costs of management, in the case for example of application to street surfaces where there is a plurality of devices in a row, one after the other, it is known to use only some of the lighting devices provided, above all during the hours when there is less traffic.

However, this partial use of the known lighting devices does not guarantee an efficient lighting of the road surface.

Moreover, gas lamps normally generate a light cone, the projection of which onto the surface to be illuminated has a diffusion of light which progressively decreases from the center toward the peripheral part. The progressive reduction of light intensity of the peripheral part of the cone projected onto the surface to be illuminated exceeds 50% of the light intensity of the central part.

Therefore, with known lighting devices, in the case of street lighting, there is not a homogeneous lighting but alternating stretches of well lit areas and others not so well lit, or dark. This also creates problems of light pollution, that is, points of very strong lighting, sometimes annoying, adjacent to areas of darkness or poor lighting.

There are also solutions known in which the gas or incandescent lamps are substituted by a plurality of low energy consumption LEDs,

This known solution, if on the one hand it reduces energy consumption, on the other it does not resolve the problem of uniformity of lighting, insomuch as the LEDs, by their very nature, emit a beam of concentrated light which consequently affects a reduced surface area. Therefore, in this type of known device, in order to guarantee a desired uniformity and a sufficient lighting cover, at least equal to that provided by the gas lamps, a high number of LEDs is required.

Doing this, however, there is a high production cost for this type of known lamp, for which reason the producers, so far, have directed their efforts toward the production and distribution of known lighting devices which provide gas or incandescent lamps, with the above mentioned disadvantages which these lamps have.

One purpose of the present invention is to achieve a lighting device which, given the same lighting cover, has both lower production and management costs and energy consumption compared to gas or incandescent lamps.

Another purpose of the present invention is to achieve a lighting device which carries out a substantially uniform lighting of a determinate surface to be illuminated, comparable or even larger than the surfaces normally covered by traditional lamps. 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,

In accordance with the above purpose, a lighting device according to the present invention comprises a support structure which supports one or more groups of LEDs able to emit relative light beams, to light a determinate surface.

In one form of embodiment, the support structure is able to be coupled with a post or other supporting structure, so as to be kept by the latter in a suspended state above the surface to be illuminated. According to a characteristic feature, the lighting device according to the present invention also comprises one or more arms disposed independent and individually directed or directable with respect to the support structure. Each arm is able to support at least a group of LEDs. By group of LEDs we mean a variable number from 2 and 20, advantageously from 2 to 1O₃ even more advantageously from 2 to 6.

Moreover, the lighting device comprises a plurality of optic members each of which is associated with at least a relative one of the LEDs of each group. Each optic member has a determinate degree of collimation, in order to direct the light emitted by the relative LED in a specific and uniform manner, in a determinate sector of the surface to be illuminated.

In this way, by directing the arms individually, and mounting an optic member with a determinate degree of collimation on each LED, it is possible to optimize the light emitted by each LED, or group of LEDs, on the relative sector, so as to obtain a substantially uniform lighting of the surface to be illuminated. In other words, with the present invention, since the light projection emitted from each LED or group of LEDs is optimized, it is possible to light, in a uniform manner, an ample surface with a reduced number of LEDs.

Therefore the lighting device according to the present invention as well as having a lower energy consumption, and therefore management costs, than known devices with gas lamps, also has reduced production costs, given the same surface illuminated, compared with known devices which use LEDs.

According to a variant, each arm is mounted on the support structure and directed with respect to the latter by means of fixed positioning elements, such as spacers, wedges or the like which determine a pre-defined position of each arm with respect to the support structure.

According to another variant, each arm is mounted on the support structure by means of adjustment means able to be selectively and individually actuated so as to adjust the position of each individual arm with respect to the support structure.

Advantageously, the adjustment means are conformed to allow the selective adjustment of the arms with respect to one, two or more axes,

According to a variant the support structure and the arms are integrated in a single pre-snaped structure, depending on the specific application of the lighting device.

In one possible solution, on one same support structure a plurality of arms are provided, each directed in a different way with respect to the others. In an alternative solution the arms have equivalent or specular directions, depending on the relative sector to be illuminated. According to another variant each arm is rigid.

According to another variant each arm is at least partially flexible, bendable or articulated.

According to another variant, each arm supports between 3 and 12 LEDs subdivided, and independently fed, into distinct sub-groups formed by a limited number of LEDs.

In this way, should one or more sub-groups of LEDs accidentally malfunction, the other sub-groups of LEDs can continue to function regularly, substantially without compromising the efficiency of the lighting device.

According to another variant, at least the LEDs of one same sub-group have the relative optic members with equivalent degrees of collimation.

According to a further variant, each LED is associated with an optic member with a different degree of collimation with respect to the others.

According to another variant, in which the arms have an equal or specular direction depending on the relative sector to be illuminated, the optic members associated with the LEDs of these arms also have an equivalent degree of collimation depending on the relative sector to be illuminated.

According to another variant , the support structure comprises at the lower part a connection element for connection to a supporting post. The connecting dement has an elastically deformable transverse section, so as to be able to adapt efficiently to different sections of the post or other supporting structures, and therefore to be easily installed even in pre-existing plants.

A method to make a lighting device according to the present invention provides to dispose a plurality of directable arms inside which a plurality of

LEDs are housed, and to associate with each LED a relative optic member so that the resulting light beams emitted by all the LEDs of the device determine a light emission which is substantially uniform with a luminosity at a minimum of 50% between maximum and minimum intensity inside the field of action of the device when it is in use.

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 shows a first form of embodiment of a lighting device according to the present invention,

- fig. 2 shows a front view of an enlarged detail of the lighting device in fig.1 ;

- fig. 3 shows a cross section of an arm of the lighting device in fig.1 ;

- fig. 4 shows a lateral view of the detail in fιg.2; - fig. 5 is a graphic representation of an example of light projection carried out with two lighting devices according to the invention disposed adjacent to each other;

- fig 6 shows a front view of a second form of embodiment of the lighting device according to the present invention; - fig 7 shows a view from above of a third form of embodiment of the lighting device according to the invention;

- fig. 8 shows a section along the line VIII-VIII of flg.7;

- fig. 9 shows a section along the line IX-DC of fig.7;

- fig. 10 shows a section along the line X-X of fig.7; - fig. 11 shows a section along the line XI-XI of fig. 7

DETAILED DESCRIPTION OF A PREFERENTIAL FORM OF

EMBODIMENT With reference to figs. 1 to 5, a lighting device 10 is in this case applied for lighting a roadway I i. In particular to light the roadway 11 a plurality of lighting devices disposed one after another along the edge of said roadway 11 are provided.

In this case, the lighting device 10 comprises a supporting post 12 installed along the edge of said roadway 11, and an arched support structure 13, mounted at an upper end of the supporting post 12, and able to support a plurality of LEDs 15 at a height of between 6 meters and about 10 meters from the roadway 11.

In particular, the mounting of the support structure 13 to the supporting post 12 occurs by means of the coaxial insertion of a tubular connector 17 of the support structure 13 on the end of the supporting post 12,

In this case the tubular connector 17 has a longitudinal notch 18 which allows a slight elastic deformation thereof, so that it adheres better to the end of the supporting post 12 and guarantees a safe and effective assembly.

The lighting device 10 also comprises a plurality of arms 16. in this case nine having an elongated shape, and each of which supports a group of LEDs 15. In this case, a group of six LEDs 15 are provided, disposed in a row for every arm 16.

Each arm 16 also comprises a transparent protection cover 22, attached to the arm 16 with relative packings, so as to guarantee a degree of safety at least equal to class IP65.

Advantageously each group of LEDs 15 is divided into two sub-groups of three LEDs 15 each, commanded and fed with a relative tension regulator 19, in an independent manner from the other sub-groups.

In this way, in the event of malfunctioning of one or more LEDs 15 in the same group, or of the tension regulator 19 of a sub-group, the possibility of all the LEDs 15 provided on the same arm 16 switching off is avoided.

To give an example, the LEDs 15 are equal to each other and are of the type fed at 24 V able to emit a cold white light with a luminosity comprised between about 70 lumen/watt and about 100 lumen/watt. The choice of these LEDs 15 allows to use back-up batteries, with the relative advantages of safety and guarantee of supply, even in the event of a blackout of the power network.

A relative collimation lens 21 is associated with each LED 15, which, depending on the specific sector of the surface S to which the light beam is directed from the LED 15, has a different degree of opening.

In this way, the distribution of the light emitted by the individual LEDs 15 is optimized and an excessive light dispersion where it is not needed is avoided.

Simply to give a non-restrictive example, the following Table 1 shows a possible configuration of the degrees of opening of the specific collimation lenses 21 for each LED 15,

Table 1

Each arm 16 is mounted on the support structure 13 according to a determinate and specific direction, so as to direct the beams of light emitted by the respective LEDs 15 according to a pre-defined direction,

In the case shown here, the nine arms 16 are attached to the support structure 13 by means of specific spacers 20, which, together with the arched shape of the support structure 13, determine the specific fixed directions of each arm 16. In the solution shown, the nine arms 16 have a substantially specular direction with respect to a hypothetical median vertical axis of the support structure 13.

In the form of the embodiment shown in fig.2, and with reference to the Cartesian comparison reported at the bottom on the left, starting from the left, the first arm 16 has an inclination of about 45°-55° with respect to the axis x and about 5°-10° with respect to the axis y; the second arm 16 has an inclination of about 45°-55° with respect to the axis x and about 20°-25° with respect to the axis y; the third arm 16 has an inclination of about 30°-40° with respect to the axis x and about 15°-20°with respect to the axis y; the fourth arm 16 has an inclination of about 15°-25° with respect to the axis x and about 20°-25° with respect to the axis y; and the fifth arm 16 has an inclination of 0° with respect to the axis x and about 20°-25° with respect to the axis y.

The sixth, seventh, eighth and ninth arms 16, as we said, have a direction specular to the respective fourth, third, second and first arms 16, In this way, the group of LEDs 15 mounted on each arm 16, assisted by the relative colliraation lenses 21, emit corresponding beams of light in a targeted and specific manner, allowing to light a determinate surface S on the roadway 11₅ in this case, having an area equal to about 25x6.5 meters.

Applicant has found that an embodiment which comes within the parameters illustrated until now is able to light the surface S with a usable luminosity comprised between about 20 Lux and about 10 Lux.

Fig. 5 shows a graphic representation of the luminous projection of two lighting devices 10 disposed at about 25 meters distant from each other.

It will be noted that in the zone comprised between the two luminous projections there is a substantial continuity of illumination of the roadway 11.

Applicant has found that in this zone the usable luminosity is comprised between about 10 Lux and about 15 Lux, that is, with a luminosity which, with respect to the better illuminated areas, assumes a value of about 50%-75%.

The lighting device 10 according to the present invention also comprises a control unit 23, for example disposed interred in a relative draining well, and able to automatically command the switching on and off of the relative lighting device 10, depending on the hours of dawn or dusk programmed or programmable,

According to a variant, the switching on and off of the lighting device 10 are commanded by a crepuscular switch 25, for example mounted on the supporting post 12 (fig. I), and associated electronically to the control unit 23.

The control unit 23 is also configured to command the modulation of the light emission of the LEDs 15, so as to reduce this intensity when there is sufficient environmental light, for example just after dusk, during the day but when the sky is very cloudy, at night when traffic is reduced to below a certain threshold, or other. Inversely, the control unit 23 commands an increase in the lighting intensity, for example during demonstrations or other events.

Applicant has found that, passing from a normal feed of about 350 mA to an increased feed of about 700 mA, there is an increase in luminosity of about 60%. According to a variant, the control unit 23 is configured for possible interface with presence sensors, for example to activate the lighting of a cycle path only when it is used, that is, detecting the passage of a user when he/she is less than 10 meters from the lighting device, According to another variant, the control unit 23 is also suitable to be programmed and controlled from a remote station connected with a direct serial cable connection, infra-red rays, WiFi technology or other.

According to the embodiment shown in fig. 6, the support structure, in this case indicated in its entirety by the reference number 113, comprises, integrated with it, the arras 116 with the relative JLEDs 15. In this case too, the arms 116 are directed or directable in a specific manner and the colUmation lenses 21 associated with the LEDs 15 have a specific degree of colUmation according to the relative sector to be illuminated.

According to the embodiment shown in figs. 7 to 11, the lighting device is contained in a fixture 26 of a substantially spherical shape.

In the solution shown here, seven arms 216 are provided, each supporting a group of LEDs 15 and disposed to occupy half of the internal volume of the fixture 26. It cannot be excluded, however, in alternative solutions, that an equal number of arms 216 are provided in a specular manner, to occupy the whole volume of the fixture 26,

In this case, each arm 216 has a bent development, or in any case not linear, so as to direct each individual LED 15 supported differently.

The sections in figs. 8, 9, 10 and 11 show some examples of arms 216 bent to direct the LEDs 15 individually. It is clear, however, that modifications and/or additions of parts may be made to the street lighting device 10 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 arm 16 is mounted on the relative support structure 13 by means of an adjustment and/or articulation mechanism. In this way, the direction of each arm can be selectively adjusted, or perfected, according to the real operating conditions of the lighting device 10. The adjustment mechanism can be conformed to provide an adjustment on one, two or more axes. According to a variant, each arm 16 is conformed so as to be able to be at least partly bent or articulated. In this way, it is possible to direct the different subgroups of LEDs 15 of the same arm 16, in different sectors of the surface S to be illuminated. It also comes within the field of the present invention to provide that the whole lighting device is fed by a photovoltaic energy accumulation plant using solar panels.

It is also clear that, although the present invention has been described with reference to specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of street lighting device with LEDs, and relative production method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

Claims

1. Lighting device comprising a support structure (13, 113) able to support one or more groups of LEDs (15) able to emit relative light beams, in order to light a determinate surface (S), characterized in that it also comprises one or more arms (16, 116. 216) disposed independent and individually directed or directable with respect to said support structure (13, 113) and each one able to support at least one of said groups of LEDs (15), and a plurality of optic members (21) each of which is associated at least with a relative one of said LEDs (15) and has a determinate degree of collimation, so as to direct in a specific and uniform manner the light emitted by the relative LED ( 15), in a determinate sector of said surface (S) to be illuminated.

2. Lighting device as in claim 1, characterized in that each arm (16, 116, 216) is mounted and directed on said support structure (13) by means of fixed positioning elements (20), able to determine a predefined position of each arm (16, 116, 216) with respect to said support structure (13, 113).

3. Lighting device as in claim 1, characterized in that each arm (16, 216) is mounted on said support structure (13) by means of adjustment means able to be selectively and individually actuated in order to adjust the position of each individual arm (16, 216) with respect to said support structure (13).

4. Lighting device as in claim 3, characterized in that said adjustment means are conformed to allow the selective adjustment of said arms (16, 216) with respect to one, two or more axes,

5. Lighting device as in claim J, characterized in that said support structure (113) and said arms (116) are integrated into a single pre-shaped structure,

6. Lighting device as in any claim hereinbefore, characterized in that each of said arras (16, 116, 216) is directed differently from the others.

7. Lighting device as in any claim from 1 to 5, characterized in that said arms (16, 116, 216) have equivalent or specular directions with respect to each other, according to the relative sector of said surface (S) to be illuminated.

8. Lighting device as in any claim hereinbefore, characterized in that each of said arms (16, 116, 216) is rigid.

9. Lighting device as in any claim from 1 to 7, characterized in that each of said arms (16. 116, 216) is at least partly flexible, bendable or articulated.

10. Lighting device as in any claim hereinbefore, characterized in that each of said arms (16, 116, 216) supports a plurality of LEDs (15) divided and fed independently in subgroups formed by a limited number of LEDs (15).

11. Lighting device as in claim 10, characterized in that at least the LEDs (15) of the same sub-group have the relative optic members (21) with equivalent degrees of coiliraation.

12. Lighting device as in any claim from 1 to 10, characterized in that each of said LEDs (15) is associated with a relative optic member (21) having a different degree of coilimation from the others.

13. Lighting device as in any claim hereinbefore, wherein it comprises at least a supporting structure (12) on which said support structure (13, 113) is mounted, in order to maintain said support structure (13, 113) in a condition suspended above said surface (S) to be illuminated, characterized in that said support structure (13, 113) comprises at least a connection element (17) to connect to said supporting structure (12), said connection element (17) being elastically deformable so as to be able to adapt effectively to the sizes of said supporting structure (12).

14. Lighting device as in any claim hereinbefore, characterized in that it also comprises a control unit (23) able to automatically command the switching on and off of said LEDs (15), according to determinate programmed or programmable parameters.

15. Lighting device as in claim 14, characterized in that said control unit (23) comprises at least a crepuscular switch (25) able to selectively command the switching on and off and the modulation of intensity of activation of said LEDs (15), according to the actual intensity of environmental light,

16. Lighting device as in claim 14 or 15, characterized in that said control unit (23) comprises at least a presence sensor able to activate lighting only when it detects a user near the lighting device (10).

17. Lighting device as in claim 14, 15 or 16, characterized in that said control unit (23) is suitable to be programmed and controlled from a remote station.

18. Method to produce a lighting device, characterized in that it provides to dispose a plurality of directed or directable arms (16, 1 16), inside which a plurality of LEDs (15) are housed, and to associate with each LED (15) a relative optic member (21), so that the resulting beam of light emitted by all the LEDs (15) determines a substantially uniform light emission with a luminosity at a minimum of 50% between maximum intensity and minimum intensity inside the field of action of the lighting device (10) when it is in use.