Lighting system comprising interconnectable lighting modules

This invention relates to a lighting system. The lighting system includes a plurality of interconnectable polygonal lighting modules, wherein each lighting module has a plurality of connection members each including at least one electrical terminal. The connection members are arranged rotationally symmetrically at the lighting module. The lighting system further includes bridge members. Each bridge member has bridge terminals and is mountable at neighboring connection members of different lighting modules, to form a bridge providing an electric connection between connection terminals of the different connection members.

FIELD OF THE INVENTION

The present invention relates to a lighting system comprising a plurality of interconnectable polygonal lighting modules.

BACKGROUND OF THE INVENTION

Lighting systems of the kind referred to here generally consist of polygonal lighting modules, i.e. light emitting modules, which are arranged to form an arrangement of a desired shape and size. For example, walls are fully or partly covered with a lighting module arrangement for displaying large images, or three-dimensional structures are formed for aesthetic applications.

One lighting system is disclosed in published US patent application Ser. No. 2005/0116667 A1. In that prior art system the lighting modules are thin building blocks called tiles, and the lighting modules are provided with electrical and mechanical connection means for interconnecting the lighting modules. These connection means are provided at the sides of the lighting modules.

However, US 2005/0116667 does not disclose any solution of how to actually design the lighting modules in order to obtain the interconnections. The electrical connections are used for powering electronic circuitry of the lighting modules. It is desirable that the lighting modules can be freely assembled to a large unit, or arrangement, without having to consider orientation of each lighting module. In other words, it is desirable that arbitrary sides of different lighting modules can be face each other.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a lighting system that has lighting modules, which are arbitrarily connectable as regards the rotation thereof.

This object is achieved by a lighting system according to the present invention as defined in claim1.

Thus, in accordance with an aspect of the present invention, there is provided a lighting system comprising a plurality of interconnectable polygonal lighting modules, wherein each lighting module has a plurality of connection members, each comprising at least one electrical terminal, which are arranged rotationally symmetrically at the lighting module. The lighting system further comprises bridge members, wherein each bridge member comprises bridge terminals and is mountable at neighboring connection members, each associated with a respective lighting module, to form a bridge providing an electric connection between connection terminals of the connection members.

By providing a connection member structure that is rotationally symmetrical, and by using separate bridge members a degree of interconnectability freedom is introduced, which is useful for enabling the a simple connection of lighting modules at an arbitrary rotation. In accordance with an embodiment of the lighting system as defined in claim2, both DC power and AC power can be used for energizing the lighting modules.

In accordance with an embodiment of the lighting system as defined in claim3, a corner connection power system is provided. The connection members arranged at the corners, i.e. at four corners of a square module or at six corners of a hexagonal module, of the polygonal lighting module can be the only connection members, or they can be combined with side connection members as well, or only side connection members can be used, as defined in claim4.

In accordance with an embodiment of the lighting system as defined in claim5, a side bridge member contains at least two terminals. The minimum of two terminals is useful for a combination of corner and side connection members, where, for each side of the lighting module, one power connection, such as a neutral connection for AC or a minus connection for DC, is connected to the corner terminals and the other, i.e. the line connection or the plus connection, is connected to the side terminal. Further options will be explained below.

In accordance with embodiments of the lighting system as defined in claims7-8, only side connection members are provided. Then, preferably, there are at least four bridge terminals for connecting at least two connection terminals of each connection member with corresponding terminals of the neighboring connection member.

In accordance with an embodiment of the lighting system as defined in claim10, a flexible bridge member for use with DC power connections is provided.

In accordance with an embodiment of the lighting system as defined in claim12, irrespective of the rotation of the lighting modules two connection terminals facing each other and belonging to different, neighboring connection members are always associated with different polarities. I conjunction with the just mentioned bridge member a totally failsafe mounting is achieved.

In accordance with an embodiment of the lighting system as defined in claim13, also a mechanical connection is obtained by means of the bridge member. Thereby, a lighting module arrangement can be assembled without any further mechanical connectors.

In accordance with an embodiment of the lighting system as defined in claim14, a combined mechanical and electrical connection is obtained. The same applies to the embodiment defined in claim15.

DESCRIPTION OF PREFERRED EMBODIMENTS

When building a lighting system a plurality of lighting modules are assembled to an arrangement of desired size and shape. In order not to have to power each lighting module individually by separate wiring the lighting modules are designed to be interconnectable. A straightforward solution to the problem of electrically interconnecting lighting modules101is shown inFIG. 1. At each side of the lighting module there are provided one positive terminal103and one negative terminal105. All positive terminals are interconnected inside the lighting module101, and so are all the negative terminals105. Terminals of the same polarity, such as positive terminals103or negative terminals105, located on neighboring lighting modules101are positioned side by side when the lighting modules101are assembled to a lighting module arrangement of desired shape and size. Then it is easy to make electrical connections between the terminals103or105of the same polarity located on neighboring lighting modules. However, this solution introduces restrictions on the orientation of the lighting modules101. In a sense they have to be marked “this side up” in order not to be erroneously mounted. If turned 90 degrees wrongly, a positive and a negative terminal would be interconnected, which would of course cause a short-circuit.

In accordance with a first embodiment of the present invention the polygonal, here square, lighting modules201, as shown inFIG. 2, of the lighting system are designed as follows. Each lighting module201is provided with a DC connection member203at each side thereof. Internally of the lighting module201the DC connection members203are connected in parallel to internal circuitry. Each DC connection member203comprises connection terminals including a positive terminal205and a negative terminal207. All positive terminals205of the lighting module201are connected with each other, and so are all negative terminals207as well. The connection members203of each lighting module201are equally directed, and the connection terminals205,207are alternately arranged, as regards the terminal polarities, along a circumference of the lighting module201, for example clockwise as indicated by the circular arrow. Thus, the connection members203are symmetrically arranged at all sides of the lighting module201. This means that it does not matter how the lighting module201is oriented in relation to neighboring lighting modules201. On the other hand, this also means that terminals of different polarities, located on neighboring lighting modules201, are positioned side by side in opposite to the above-mentioned straightforward solution. Thus, they must not be directly engaged with each other.

However, the lighting system according to this invention further comprises bridge members. The wiring of one embodiment of a bridge member601is shown inFIG. 6. InFIG. 3such bridge members601are mounted on every connection member on every lighting module303in the arrangement301. Each bridge member601is mountable at two neighboring DC connection members, each associated with a respective lighting module303. The bridge member601forms a bridge providing an electric connection between terminals of equal polarity of the two DC connection members. The bridge member601is provided with four-bridge terminals607a-d, which is arranged in the corners of a rectangle and which is diagonally interconnected by means of crossing wires603,605. Thereby it is ensured that irrespective of how the bridge member601is rotated when mounted on the connection members203the respective positive terminals205are interconnected and the respective negative terminals207are interconnected. Of course the cross-wires603,605are insulated from each other. A DC power source module305, which is provided with a connection member of the same type as those of the lighting modules303is connected to one of the lighting modules303by means of a bridge member601.

Referring toFIG. 4, in one embodiment the bridge member401comprises a body403, which is of an insulating material and has a U-shaped cross-section, four metal clamps405rectangular arranged in pairs close to the respective ends of the body403, and the wires603,605mentioned above. The metal clamps405correspond to the above-mentioned bridge terminals607a-d. The body403consists of a bottom plate407and opposite long side wall plates409extending perpendicularly to the bottom plate407and being joined with the bottom plate407at the long sides thereof. Preferably, the side wall plates409are integral with the bottom plate407. The clamps405of each pair are arranged opposite to each other at the insides of the long side wall plates409, that is at the sides facing each other. Each lighting module411is basically brick shaped, as shown inFIG. 15. It has a front plate413, which typically are a diffuser, sidewalls414and a rear plate419. The rear plate is provided with four elongated holes421, one at each side of the lighting module411, for receiving the bridge members401. Each lighting module411has a connection member415comprising a wall portion416of the sidewall414and two longitudinally spaced contact elements417. The contact elements417are fastened on said wall portion416on an inwardly, i.e. towards the inner area of the lighting module411, facing side thereof.

When assembling two lighting modules411, they are pushed or shifted together such that their respective connection members415abut on each other. Then, the bridge member401is forced down onto the connection members415until the bottom plate407of the bridge member401abuts on upper long side edges of the wall portions416. Then the metal clamps405have made contact with the contact elements417of the connection members415. Thereby electrical connection has been established between the lighting modules411. Additionally the bridge member401mechanically clamps the lighting modules411together.

According to an alternative embodiment of the bridge member and connection member, as shown inFIG. 5, the basic shape and structure of the bridge member501and the connection member is the same but the terminals are different. Thus, the contact elements of the connection member515are constituted by pins and the bridge terminals505are constituted by sockets.

According to an advantageous second embodiment of the lighting system, as shown inFIG. 7, a lighting module701comprises merely corner connection members703and corner bridge members705, also shown at1101inFIG. 11. Each corner connection member701consists of a corner connection terminal703, shown at1105inFIG. 11. The corner connection terminals703,1105are alternately interconnected. For example, in the shown embodiment where the lighting modules701are squared, the corner connection terminals703,1105are interconnected in pairs diagonally of the lighting module701. The corner bridge member1101has four legs, constituting corner bridge terminals1103, which are mountable at corner connection terminals1105. All the corner bridge terminals1103are interconnected. Thus, the corner bridge member705,1101, at a maximum, interconnects four corner connection terminals, one on each lighting module of four neighboring modules701, thereby feeding a power of a certain polarity that has been applied to one corner connection terminal703,1105of a lighting module701to the other three corner connection terminals. In this embodiment the corner bridge terminals1103are positioned at the corners of a square, and they are formed as pins, which fit into the corner connection terminals, which are formed as sockets. In addition to the electrical connection, the corner bridge members705provide mechanical connection between the lighting modules701.

The corner connection terminals703of a first polarity are also connected to a first input terminal of a common rectifier bridge711, and the terminals of a second polarity are connected to a second input terminal of the rectifier bridge711. In this embodiment, the rectifier bridge711is a diode rectifier bridge, of a kind called Graetz rectifier. The rectifier bridge711rectifies input AC power equally, irrespective of which corner connection terminals are connected to which polarity, i.e. line or neutral, of the power source. The same is true for a DC power source, where the polarities are plus and minus. It should be noted that the rectifier bridge711might be preceded by transformer in order to lower an input AC voltage, if required. On the other hand this alternative is an AC only solution. According to an alternative embodiment of the lighting module1301having merely corner connection members, the corner connection members1303are formed as twin members. Thus, each corner connection member1303has two connection terminals1305,1307, which are arranged close to the corner of the lighting module1301, but at two different sides thereof. In each corner connection member1303the terminals1305,1307are interconnected. Further, in this embodiment as well, the corner connection members1303are diagonally interconnected in pairs. From one manufacture point of view, the twin members are preferred before the single corner members.

The above-described embodiments of the lighting module having only corner connection members, which are connected in pairs diagonally of the lighting module, the corner connection members can be regarded as one example of diagonally interconnected connection members, and another one is shown inFIG. 14. These diagonally interconnected connection members1403are arranged at a considerably longer distance from the corners of the lighting module1401. They are even closer to the center of the lighting module1401than corners thereof. There are advantages with this embodiment, while a disadvantage is the size of the bridge members1405. Each bridge member1405still interconnects four lighting modules1401. The closer to the center of the lighting module1401the connection members1403are located, the closer to the size of the lighting module the size of the bridge member1405gets. Thus, each connection member1403of the lighting module is arranged at a bisector of a respective corner of the lighting module. This definition also includes at least all embodiments of the corner connection members.

InFIG. 12a schematic diagram of the diode bridge1201is shown. Seen from the output terminals1203,1205the bridge consists of four diodes arranged in two parallel branches extending between the output terminals1203,1205. Each branch has two series connected diodes1211. Each one of the input terminals1207,1209is connected to a respective branch at a point between the diodes1211. Considering the fact that a regular diode has a threshold voltage of approximately 0.75V, an input voltage will drop about 1.5V when passing the diode bridge1201. Consequently, it is an advantage to combine the diode bridge with a DC/DC converter1213, and use a high voltage AC power source, such as a mains AC voltage.

Referring now toFIG. 8, in a third embodiment of the lighting system each lighting module801has side as well as corner connection members803,805, which are connected to a rectifier bridge807. The side connection members are interconnected, and the corner connection members are interconnected. Thus, the corner connection members805all have the same polarity, and the side connection members have the same polarity. The corner bridge member1101described above is mountable on these corner connection members805as well. Each side connection member contains a single terminal. An appropriate side bridge member, being half of a side bridge member shown inFIG. 9, to be described below, has two terminals, which are mountable on the side connection terminals803of the side connection members803of two neighboring lighting modules801. Also in this embodiment both AC and DC power supply can be used. A power supply contact809is connected to the corner and side connection members805,803of one side of one of the lighting modules801.

Referring now toFIG. 9, a fourth embodiment having only side connection members is shown. In the figure assembled lighting modules901, side bridge members903, rectifier bridges905and a power supply contact907are shown. Similar to the bridge members601of the first embodiment described above, each side bridge member903contains four side bridge terminals909. However, in this embodiment the bridge terminals909are interconnected in pairs transversal of the bridge member rather than diagonally. The pairs are spaced along the side of the lighting module901. Thus, two connection terminals arranged on neighboring lighting modules901, and facing each other are interconnected by means of the bridge member903. Alternatively, it is possible to use diagonal interconnections.

Referring now toFIG. 10a fifth embodiment of the lighting system comprises lighting modules1001having a combination of corner and side connection members1003,1005, just like the lighting modules of the third embodiment described above. On the contrary, in this embodiment the lighting modules do not have rectifier bridges. They are meant for DC supply only. All corner connection members have terminals of a first polarity, such as minus, and all side connection members have terminals of a second polarity, such as plus.

Referring now toFIG. 16a sixth embodiment of the lighting system comprises lighting modules1601, which have symmetrical side connection members1603. The symmetry means that the connection terminals1605of each connection member1603are arranged symmetrically about, or are mirrored in, a central plane of the connection member1603. For example, in the shown embodiment, there is a central negative terminal1605a, which is placed in the central plane, and a positive terminal1605b,1605cat each side of the negative terminal1605a. Other examples of terminal combinations are shown inFIG. 17. Thus, in a first example inFIG. 17, from one end to the other end of the connection member there are four consecutive terminals1701arranged along a side of a lighting module, consisting of a positive terminal followed by two negative terminals and finished by another positive terminal. In this first example, the central plane is positioned in the middle between the negative terminals1701. In a second example there are five consecutive terminals1702, consisting of a positive terminal, a negative terminal, a data terminal, a negative terminal, and a positive terminal. In a third example, there are six consecutive terminals1703, consisting of a positive terminal, a negative terminal, two data terminals, a negative terminal, and a positive terminal. In another example, there are nine terminals1704including power as well as data terminals. The terminals may be of further types as well, such as PWM signals to light elements of the lighting module, as shown at1705in a further example inFIG. 17.

When the connection member1603is symmetrical at least for one signal there are more than one connection terminal available. A drawback of such multiple connection terminals is that they increase the size of the connection member1603. However, an advantage thereof is that, since the current can be spread over multiple terminals, the current rating of the connection member1603can be lowered in comparison with a non-symmetrical connection member having a minimum number of connection terminals.

Further, the symmetrical connection members in a sense simplify the bridge members. No cross-connection between terminals is necessary, but the bridge member has simple parallel wires. Each wire extends straight between opposite bridge terminals, which interconnect two opposite connection terminals of two connection members1603belonging to two adjacent lighting modules1601.

The electrical connection of adjacent lighting modules according to the present invention provides for flexibility in rotation of the lighting modules that allows for non-square shapes of the lighting modules. For example, the lighting modules can be rectangular as shown inFIG. 18. For example, if the rectangular lighting modules1801have side connection members1803a short side of one lighting module1801is connectable to the long side of another lighting module1801. However various shapes are possible, for instance shapes usable for forming curved or Y-shaped lighting systems.

The lighting system consisting of multiple interconnected lighting modules has an advantage of being powerable at a single power connection at one of the lighting modules, since the power is then forwarded via the connection members from module to module throughout the system. However, a lighting module is only capable of conducting a limited current. Since the module connected to the external power supply has to carry the current of all modules the maximum number of modules in the system becomes limited as well. A solution to that problem is to use multiple external power supplies, which are connectable in parallel and which are distributed over the lighting system, an example of which is shown inFIG. 19. The exemplifying lighting system1901has 30 lighting modules1903. Further, each power supply1905is an AC/DC converter having a limited power. Then there is no need for an internal converter of each module1903. Assume that each power supply1905is capable of powering up to 10 modules and that each module is capable of conducting a maximum current, which is sufficient for supplying 10 modules. Then three power supplies1905are needed, connected to a respective one of the modules1903and well distributed over the system1901. If all three power supplies would be connected to the same module1903an over current would occur in that module. In order to obtain an amount of flexibility with respect to the placement of the power supplies, there is introduced a large enough tolerance on the current conduction capability of each module. The flexibility thus obtained is illustrated inFIG. 20. It should be noted that the current throughout the lighting system2001would redistribute itself if the power supplies2005were not equally distributed among the lighting modules2003.

Above, embodiments of the lighting system according to the present invention have been described. These should be seen as merely non-limiting examples. As understood by a skilled person, many modifications and alternative embodiments are possible within the scope of the invention.

Thus, as explained by means of the embodiments above, an easy to use solution for how to interconnect lighting modules electrically, but also mechanically, while providing full rotational freedom when assembling the lighting modules is obtained. The lighting modules are typically provided with connection members at their sides or their corners or both. Bridging members are provided. They are mounted at the connection members for interconnecting terminals thereof. Preferably, in addition, the bridging members act as mechanical clamps.

It is to be noted, that for the purposes of this application, and in particular with regard to the appended claims, the word “comprising” does not exclude other elements or steps, that the word “a” or “an”, does not exclude a plurality, which per se will be apparent to a person skilled in the art.