Abstract:
A lighting device for mounting on a mounting surface may include: a planar solid state lighting module having a light emitting region and peripheral holes for fixing members to the mounting surface to extend therethrough, a peripheral gasket extending along the periphery of the lighting module; the gasket having, at the holes of the lighting module, ear-like extensions having a perforation therein, said ear-like extensions extending inwardly of the gasket to align the perforations therein with the holes in the lighting module, a housing which frames the lighting device with the gasket applied onto the lighting module. The housing has apertures aligned with the holes in the lighting module and the perforations in the ear-like extensions of the gasket, as well as a window to expose the light emitting region of the lighting module, with a light permeable screen which sealingly closes said window.

Description:
RELATED APPLICATIONS 
       [0001]    The present application claims priority from Italian application No.: TO2012A000888 filed on Oct. 11, 2012. 
       TECHNICAL FIELD 
       [0002]    The present description relates to lighting devices. 
         [0003]    Various embodiments can relate to lighting devices using LED sources as light radiation sources. 
       BACKGROUND 
       [0004]    The name Zhaga represents a consortium of cooperation between companies of the lighting industry which was set up with the aim of making it easier to interchange solid state lighting sources, for example of the LED type, made by different manufacturers so as to facilitate, for example, general lighting applications. 
         [0005]    The International Protection (or IP protection class, a name also interpreted as Ingress Protection) is a code which, in the electrical field, summarizes the level of protection of an apparatus against contact with the human body or with objects and against the penetration of environmental agents. 
         [0006]    At present, there are no lighting devices compliant with the Zhaga directives which are also able to offer a certain degree of IP protection. Under these conditions, a Zhaga module cannot be used as a component on its own, that is to say without further protective elements. As a result, when Zhaga modules are used, it may be necessary to also use, in addition to a heat sink normally provided for the mounting of the lighting module, further additional components intended to ensure a degree of IP protection. By way of example, in various solutions, the Zhaga modules may need to be combined with a protective housing, a plastic cover or other components so as to prevent dust, humidity, water and other environmental agents from penetrating into the lighting device, thus damaging the LED module. 
       SUMMARY 
       [0007]    Various embodiments provide lighting devices which can be compliant with the Zhaga directive and at the same time can exhibit a degree of IP protection. 
         [0008]    Various embodiments make it possible to provide for one or more of the following advantages:
       compliance with the Zhaga directives in terms of thermal, mechanical and optical characteristics, with simultaneous IP protection;   applicability inside or outside, including street lighting applications;   readily available for use in a lighting system without the need to use other components for the IP protection, the protection already being ensured by the device itself;   applicability of the solution and of the related design models to a large range of dimensions of lighting devices and/or to a large range of shapes;   the absence of restrictions linked to the selection of a particular shape (for example rectangular), with a broad choice from other shapes, for example round, elliptical, mixed line, etc., retaining conformity with the Zhaga directives.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    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 disclosed embodiments. 
           [0015]    In the following description, various embodiments described with reference to the following drawings, in which: 
           [0016]      FIG. 1  is an exploded perspective view of one embodiment, 
           [0017]      FIGS. 2A and 2B , and  FIGS. 3 to 6  show various components and assembly phases of embodiments, and 
           [0018]      FIG. 7  shows one embodiment mounted on a mounting surface. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    The following detailed description refers to the accompanying drawing that show, by way of illustration, specific details and embodiments in which the disclosure may be practiced 
         [0020]    In the following description, various specific details aimed at providing a fuller understanding of various exemplary embodiments are explained. The embodiments may be implemented without one or more of the specific details or using other methods, components, materials, etc. In other cases, known structures, materials or operations are not shown or described in detail so that the various aspects of the embodiments may be understood more clearly. 
         [0021]    The reference to “an embodiment” in the context of this description indicates that a particular configuration, structure or feature described in relation to the embodiment is included in at least one embodiment. Therefore, phrases such as “in one embodiment”, which may occur at various points in this description, do not necessarily refer to the same embodiment. Moreover, particular forms, structures or features may be combined in any suitable manner in one or more embodiments. 
         [0022]    The reference signs used here are provided solely for the sake of convenience and therefore do not define the scope of protection or ambit of the embodiments. 
         [0023]    In the figures, the reference sign  10  denotes a lighting device intended to be mounted on a mounting surface S, which can be formed, for example, by the surface of a heat sink (not shown as a whole). 
         [0024]    The device  10  shown here can be considered to be an example of any kind of lighting device, for example compliant with the Zhaga specifications. 
         [0025]    The rectangular shape shown here is therefore to be considered to be purely an example from a wide range of shapes and configurations which the device  10  can adopt. In various embodiments, in addition to being compliant with the Zhaga directives, the device  10  can also exhibit a degree of IP protection. 
         [0026]    In various embodiments, the device  10  can include, proceeding ideally from bottom to top in the exploded perspective view in  FIG. 1 :
       a lighting module  12  acting as a light radiation source formed, for example, by a solid state lighting module, for example of the LED type,   a sealing gasket  14 ,   a housing  16 ,   means for fixing on a mounting surface S (for example the surface of a heat sink shown in  FIGS. 6 and 7 ), these fixing means can include, for example, screws  18  which can be screwed into corresponding holes (not shown in the drawings) provided in the surface S, moreover ensuring the connection between the various parts  12 ,  14  and  16 , and   a screen  20  for protecting the region of the module  12  where the light radiation sources are located.       
 
         [0032]    In various embodiments, the module  12  can include a substrate  12   a  (for example formed with a solution equated to a printed circuit board (PCB)) “populated” by one or more light radiation sources, for example organized in an array  12   b  of solid state light radiation sources, for example of the LED type. 
         [0033]    In the exemplary embodiment shown, the array  12   b  is ordered with a matrix pattern. In various embodiments, the array  12   b  can have a different distribution, for example a quincuncial distribution. 
         [0034]    As already mentioned, the dimensions and the thermal and optical properties of the module  12  can be as desired, for example compliant with the Zhaga standards. 
         [0035]    In various embodiments, the module  12  can be provided with a plurality of holes  12   c  for the screws  18  to extend therethrough. 
         [0036]    In various embodiments, the holes  12   c  can be positioned peripherally, that is along the perimeter of the module  12 . 
         [0037]    In various embodiments, the gasket  14  can be made with a flexible material, for example an elastomer such as silicone. 
         [0038]    In various embodiments, the gasket  14  can have a profile or form which is modeled on the outline of the module  12  such that it can be applied onto said outline, that is to the periphery of the module  12 . 
         [0039]    As can be seen more clearly in  FIG. 2A , the gasket  14  (which has, in the embodiment shown by way of example here, a rectangular profile matched to the equally rectangular outline of the periphery of the module  12 ) has ear-like protruding parts  14   a  in positions corresponding to the positions of the holes  12   c  provided in the module  12  (that is, in the examples shown here, at the angular parts of the rectangular shape of the module  12 ). 
         [0040]    The ear-like parts  14   a  have perforations  14   b  (for example made by molding during the formation of the gasket  14  or obtained by piercing the respective ear-like part  14   a  after the formation of the gasket  14 ). 
         [0041]    The flexibility of the material from which the gasket  14  is made ensures that the ear-like parts  14   a  can be turned toward the inside of the outline of the gasket  14  (see the sequence of  FIGS. 2A and 2B ) so as to align the perforations  14   b  with the holes  12   c  in the module  12  (see for example the bottom part of the exploded perspective view of  FIG. 1 ). 
         [0042]    In various embodiments (and as can be seen more clearly by comparing the exploded perspective view of  FIG. 1  and the view “from the bottom” of  FIG. 4 ), the housing  16  can have a tray-like general shape so as to ensure that the housing can “frame” the module  12 . 
         [0043]    In various embodiments, in the bottom part of the tray-like shape, the housing  16  can indeed comprise a window  16   a  intended to extend at the light emitting region, i.e. at the region of the module  12  where the light radiation sources  12   b  are located. All this leaving the region  12   b  uncovered so as to make it possible to project the light radiation produced by the sources  12   b  outwardly of the device  10 . 
         [0044]    In various embodiments, the housing  16  can include apertures (for example holes)  16   b  intended to extend in alignment with the perforations  14   b  in the gasket  14  and with the holes  12   c  in the module  12 . This allows for the passage of the screws  18  intended to fix the device  10  on the mounting surface S and to “hold together” the module  12 , the gasket  14  and the housing  16  itself. 
         [0045]    In various embodiments, the tray-like shape of the housing  16  has the effect that the inner side of the housing  16 , intended to be turned toward the module  12  and the gasket  14 , has, along the outline of the window  16   a , an as a whole “recessed” portion  160 , surrounded by a peripheral rim  16   c : the term “recessed” clearly refers to the viewpoint of  FIGS. 4 and 5 , where  FIG. 5  is a view, shown on an enlarged scale, of the portion of  FIG. 4  denoted by the arrow V. 
         [0046]    The housing  16  thus constitutes a type of frame which is able to internally receive the module  12  with the interposition of the gasket  14 . 
         [0047]    For this purpose, in various embodiments, the recessed portion  160  can have, around the apertures  16   b , imprints or “indentations” 160   a  which are able to internally receive the ears  14   a  of the gasket  14  that are folded toward the inside of said gasket, as shown schematically in  FIG. 2B . 
         [0048]    In various embodiments, the housing  16  can therefore be produced in such a way that it simultaneously adapts to the module  12  and to the gasket  14 . 
         [0049]    In various embodiments, the assembly formed by the module  12 , by the gasket  14  and by the housing  16  can be “held together” by the screws  18  which are screwed into the substrate (see  FIG. 6 ) and extend through the apertures  16   b  in the housing  16 , the perforations  14   b  in the ear-like extensions  14   a  of the gasket  14  which are folded internally of the gasket  14  and the holes  12   c  in the lighting module  12  so as to retain the gasket  14  sealingly sandwiched between the lighting module  12  and the housing  16 . 
         [0050]    In various embodiments, once it has been fixed on the surface S using fixing means such as the screws  18 , the module  12  can be subjected, by the housing  16 , to a uniform pressure such as to ensure:
       on the one hand, that the module  12  adheres to the surface S of the mounting substrate, so as to make it possible to dissipate the heat produced by the sources  12   b , in particular when the substrate is configured as a heat sink,   on the other hand, that the external agents cannot penetrate into the device at the interfaces between the module  12  and the gasket  14  and between the gasket  14  and the housing  16 .       
 
         [0053]    This also applies at the holes  12   c  and at the apertures  16   b  owing to the presence of the ear-like parts  14   a  of the gasket  14 , which act as annular gaskets capable of surrounding the passage through which the screws  18  extend. 
         [0054]    Under these conditions, for the main points corresponding to those shown in the bottom part of  FIG. 6 , the device  10  can satisfy the mechanical, thermal and optical requirements of the Zhaga standards. 
         [0055]    In view of the presence of the window  16   a  to make it possible for the light radiation emitted by the sources  12   b  to be projected outwardly of the housing  16 , the upper part of the device could remain open, with the light radiation sources  12   b  and the area of the substrate of the module  12  which surrounds them still being exposed to the external agents, with the risk of being damaged. 
         [0056]    For this purpose, in various embodiments, the window  16   a  can be covered by the screen  20  made of a generically “light permeable” (that is transparent) material. 
         [0057]    In various embodiments, the screen  20  can be made of vitreous material or of plastic. 
         [0058]    In various embodiments, the screen  20  can be applied so as to cover the window  16   a  (see  FIG. 7 ) by sticking it peripherally (for example using a silicone-based glue) to the outline of the window  16   a.    
         [0059]    In various embodiments, the screen  20  can be formed in one piece with the housing  16 . 
         [0060]    In various embodiments, the screen  20  can be made (for example in such a way as not to change the optical features of the system) so as to comply, also with respect to the dimensions, with the Zhaga specifications. 
         [0061]    In various embodiments, the screen  20  can be applied to the housing  16  leaving the screws  18  uncovered so as to allow for the possible removal of the device  10  from the substrate S without having to detach the screen  20  from the housing. 
         [0062]    Owing to the screen  20 , the device  10  once applied to the mounting surface S is protected against the penetration of water, dust or any other external agent both through the side walls and through the upper part. 
         [0063]    As a result, in various embodiments, the device  10  can comply with the Zhaga directives and at the same time exhibit IP protection. 
         [0064]    The device  10  can therefore be used for the final application without the need for additional components, it being able to be simply fixed on the surface S of the mounting substrate, which can have, for example, heat sink properties. 
         [0065]    The device  10  can be used for any lighting application, it being able to be mounted directly inside a lighting device without the need for additional protection (for example a glass or plastic cover). 
         [0066]    In various embodiments (also owing to the presence of the gasket  14 , which extends around the insertion holes of the screws  18 , and owing to the protective action provided by the screen  20 ), it is therefore possible to prevent any penetration into the device  10  of external agents which are capable of damaging the light radiation sources  12  and the circuits which may be present on the substrate  12   a , thereby ensuring compliance with the Zhaga specifications. 
         [0067]    While the disclosed embodiments has 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.