Abstract:
A modular lighting device may include an elongated support member with electrically powered light radiation sources. The support member includes at least one electrically conductive layer with a covering layer applied thereon, wherein said covering layer exhibits discontinuities forming a marker array for cutting to length modular lighting device.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to Italian Patent Application Serial No. TO2014A000764, which was filed Sep. 26, 2014, and is incorporated herein by reference in its entirety. 
       TECHNICAL FIELD 
       [0002]    Various embodiments may generally relate to lighting devices. 
         [0003]    One or more embodiments may find an application in lighting devices employing solid state light radiation sources such as, for example, LED sources. 
       BACKGROUND 
       [0004]    Linear LED modules are an example of lighting devices exhibiting modularity. Modularity in a product enables cutting the module to length at certain fixed points. 
         [0005]    In various implementations, the cutting points and the corresponding circuit are visible to the final user from the front or top side (i.e. the side carrying the light radiation sources, e.g. the LEDs) or they may be made visible via a particular marking (e.g. ink or laser printing). 
         [0006]    In a protected module, where no transparent materials are used, the cutting points which may be present on the device support (for example a Printed Circuit Board, PCB) may not be recognizable through a direct observation of the circuit and/or the marking. When an opaque material is used, it is impossible to identify the cutting points by observing the position of the LEDs or the associated electronics, which are not visible. This is an intrinsic limit for those applications wherein the module must be cut to length. 
         [0007]    This problem may be countered in protected modules through a marking (e.g. a laser marking) of cutting points on one side of the module. The alignment of cutting points may be based on the position of the light radiation sources, adapted to be the only visible components. 
         [0008]    This approach is critical due to the tolerances of the marking, to the possible shrinkage of different materials during the process and to the need, in the positioning of the module, of aligning the marking with the layout of the support (e.g. of the PCB). 
         [0009]    These problems have been found to be virtually unsolvable if the support (e.g. the PCB) and/or the components are not visible to the final user, so that the module may be cut but, for example, without offering the possibility to reconnect a part of the module. 
       SUMMARY 
       [0010]    Various embodiments aim at overcoming the previously outlined drawbacks. 
         [0011]    According to various embodiments, said object is achieved thanks to a lighting device having the features specifically set forth in the claims that follow. 
         [0012]    Various embodiments may also concern a corresponding method. 
         [0013]    In various embodiments it becomes possible to obtain a lighting module, e.g. a LED lighting module, adapted to be cut in different points without the need of seeing the module top side. 
         [0014]    Various embodiments may achieve one or more of the following advantages:
       the possibility to cut the module to length even when the top or front side of the module is completely masked or covered, with the consequent impossibility to find any reference point for the cutting,   the possibility to implement the connection of the module on both the top and the bottom side,   a higher flexibility in production, thanks to the presence of reference positions also during in-line testing or laser marking, without negative effects due to components tolerances, also as regards the positioning and assembling thereof,   a lower cost of raw materials, thanks to the possibility to use e.g. a solder mask instead of a PI coverlayer at the bottom or back layer.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the invention are described with reference to the following drawings, in which: 
           [0020]      FIG. 1  is a perspective view of a device according to various embodiments, 
           [0021]      FIG. 2  is a view of a device according to various embodiments, viewed from an observation point approximately opposite the observation point of  FIG. 1 , and 
           [0022]      FIG. 3  is a view highlighting features of a device according to various embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    In the following description, numerous specific details are given to provide a thorough understanding of one or more exemplary embodiments. The embodiments may be practiced without one or several specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring various aspects of the embodiments. Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the possible appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, particular features, structures, or characteristics may be combined in a suitable manner in one or more embodiments, and/or may be associated to the embodiments in a different way from what is shown herein, so that e.g. a feature herein exemplified in connection to a Figure may be applied to one or more embodiments exemplified in a different Figure. 
         [0024]    The headings provided herein are for convenience only, and therefore do not interpret the scope or meaning of the embodiments. 
         [0025]    In the Figures, reference  10  denotes on the whole a solid state lighting device. 
         [0026]    This lighting device may consist, in various embodiments, of a so-called LED module, including electrically powered light radiation sources  12 , e.g. LED light radiation sources, arranged on an elongated support member  14 . 
         [0027]    As far as the present description is concerned, device  10  may be considered as including a (optionally flexible) bar or strip of a generally undefined length. In various embodiments the need is present to cut such a module  10  to length, at cutting positions which are identified with sufficient precision, so as to obtain a lighting device of a desired length. 
         [0028]    Support member  14  may have different shapes, according to the adopted implementation. 
         [0029]    For example, support member  14  may include an elongated support element  16 , e.g. a Printed Circuit Board (PCB). 
         [0030]    In various embodiments, on the basis of the application and design requirements (power supply currents, features of electronic circuits, thermal characteristics), support board  16  may include various layers of a conductive material, e.g. copper. 
         [0031]    In various embodiments, there may be provided a single layer PCB  16 , having one single layer of conductive material applied on the base material, e.g. by using a special adhesive. 
         [0032]    The exposed side of the conductive layer may require covering via a covering layer  18 , adapted to prevent the conductive metal layer (e.g. copper) from oxidizing. 
         [0033]    In various embodiments, there may be provided a double layer PCB  16 , having two layers of conductive material (e.g. copper) applied on the opposing sides of a base material layer. In this case, too, there may be provided a covering layer  18 , e.g. having a protection function of the electrically conductive layers. 
         [0034]    In this regard it may moreover be observed that, in lighting (e.g. LED) modules as exemplified herein, the light radiation sources and the components associated thereto may be mounted on the top or front side of module  10 , while the bottom (or back) side is not used for mounting components and is coated by a cover layer  18  to ensure electrical isolation. 
         [0035]    In various embodiments, the covering layer may be made of different materials, such as resins as polyimmide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN). 
         [0036]    When there is no need to provide an electrical insulation, the covering layer may consist of a finishing material (Organic Solderability Preservative (OSP), silver, gold, etc.). 
         [0037]    In various embodiments, such a covering layer  18  may also include or consist of a solder mask. 
         [0038]    Whatever the specific implementation details, in such a modular device  10  both the light radiation sources (e.g. LEDs  12  shown in  FIG. 1 ) and the electrical contacts, e.g. dedicated pads connected to such sources, may not be visible from the outside. 
         [0039]    In various embodiments, as schematically shown in  FIG. 3 , covering layer  18  (whatever it may consist of) may have, as better exemplified in  FIG. 3 , discontinuity areas  20 , which are located for example at the bottom (or back) side of module  10  and through which the pads of electrical (and/or possibly thermal) contact are visible. 
         [0040]    This may take place also if on the bottom (or back) side of module  10  there is applied a further layer  22  of a light permeable (transparent) material, adapted to seal device  10  while imparting protection features against the penetration of foreign agents (IP protection). 
         [0041]    In various embodiments discontinuities  20 , which are regularly spaced along the lengthwise extension of device  10 , may create a marking scale for cutting to length modular lighting device  10 . 
         [0042]    In this way, discontinuities  20  may act as markers for the cutting operation, being arranged according to a regular pattern, e.g. as openings in covering layer  18  (whatever the latter may be: a cover layer, a solder mask, etc.). 
         [0043]    Thanks to their regular distribution, discontinuities  20  may therefore act as an array of markers, which are located at particular positions along the lengthwise extension of module  10  (axis X 10  in  FIG. 3 ), creating references which enable cutting module  10  to length (see for example the cutting line denoted by T in  FIG. 3 ) without the need of markers located, e.g., on the front (or top) side or on the lateral sides of module  10 . 
         [0044]    It will be appreciated, moreover, that the solution according to various embodiments can be applied also in those cases wherein (unlike the previously described examples) the observation of the front side or of the lateral sides of module  10  might in itself enable spotting the position of components within module  10 . 
         [0045]    Various embodiments enable the alignment of a laser marking with respect to the layout of board  16  (e.g. in order to identify the positions of light radiation sources  12 ). This operation may be performed e.g. on an edge of a protected module  10  where an opaque material is present on the front side, so as to mask all components, including LEDs, while a transparent material  22  is applied on the bottom or back side of module  10 , in order to provide the latter with an IP (Ingress Protection). 
         [0046]    It will be appreciated that various embodiments enable to keep a high level of accuracy in the production and in the identification of circuits by final users. This applies e.g. to the position of light radiation sources  12 : the marking layout given by discontinuities  20  in covering layer may actually correspond to the circuit layout, adapted to be implemented with a higher accuracy than is the case with the positioning of components on the circuit itself, which may be affected by size, positioning and assembling tolerances. 
         [0047]    In various embodiments, a laser marking may be controlled by a camera observing the back side of module  10 . 
         [0048]    This advantage may be appreciated also during production, as discontinuities  20  in cover layer  18  may correspond to openings for accessing electrical connection pads for the module components. This may e.g. simplify testing operations, giving the possibility to extend testing operation to an access on both front and back side of module  10 . 
         [0049]    While the disclosed embodiments have been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the disclosed embodiments as defined by the appended claims. The scope of the disclosed embodiments is thus indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced.