Abstract:
A channel letter or light box illumination apparatus wherein the channel letter or light box is illuminated from a luminaire located at some distance from the channel letter or light box, ideally in a location expeditious to servicing replaceable components such as lamps and driver electronics. A light engine includes one or more light ports, with each port capable of conveying light via optical light guides for the purpose of illuminating a portion or entirety of the light box or channel letter. A singular light guide or plurality of light guides enters the side or rear of the channel letter or light box and are coupled to side-lit light guides. The side-lit light guides, which may be bent and formed, convey light and distribute it through out the channel letter or light box.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority from U.S. Provisional Patent Application Ser. Nos. 60/763,118 and 60/763,119, both of which were filed on Jan. 27, 2006, and entitled, respectively, “Apparatus for Remotely Illuminating Channel Letters and Light-Boxes” and “Apparatus for Illuminating Channel Letters and Light Boxes”, the contents of which are hereby fully incorporated by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to lighting apparatus, such as in the context of large-scale signing, and to specific arrangements of light provision and distribution sources.  
       BACKGROUND OF THE INVENTION  
       [0003]     Traditionally, in the signing industry, particularly in connection with large illuminated signs as may be used in advertising or in appending large, illuminated labels to buildings, channel letters and light boxes have become standards. Typically, they have been illuminated internally with neon and fluorescent tubes, incandescent lamps, and more recently with light emitting diode (LED) technology. All of these technologies require the use of transformers, driver electronics, and electrical contacts to be located in the channel letter or light box “can”, or holding structure, which may normally have metal sides and a translucent plastic face. In many instances, channel letter signs and light boxes are located in places that are not easy to access, for example, at the top of a multi-story building. Thus, replacing serviceable parts and repairing malfunctioning components can be time-consuming, costly in terms of labor and equipment, and potentially dangerous. A compelling need has thus been recognized in connection with illuminating channel letter signage and light boxes in a manner to permit serviceable components to be located in locations that are easy to access.  
         [0004]     Fiber optic technology has provided many advantages in a variety of contexts and has been contemplated previously in connection with lighting applications. End-lit fibers emit light at terminal ends of fibers while very little light typically is emitted through the cylindrical fiber walls. U.S. Pat. No. 6,024,476 relates to the use of “end-lit” fibers in lighting. There, bunches of end-lit fibers are grouped together to create an aggregately much greater light output than is possible with a single end-lit fiber. Apart from the intricacies encountered in connection with bunching the fibers together, they are prone to easy breakage when bunched and difficult to maintain or replace. Moreover, retrofitting an existing channel letter in the manner taught by this patent would be impractical.  
         [0005]     “Side-lit” fibers, in contrast, emit light isotropically through the cylindrical walls of a fiber, that is, outwardly along an infinite number of radial directions as defined with respect to a central longitudinal axis of the fiber. U.S. Pat. No. 6,123,442 describes the use of side-lit fibers in lighting. However, it has been found that the light provided by such fibers is often inconsistent and unpredictable, especially when intricate configurations (e.g. of letters or numerals) are contemplated. Also, maintenance is difficult and costly in that entire lengths of fiber often need to be replaced even in the case of minor performance issues. Moreover, since side lit fiber is designed to lose or emit light along its length, as the distance between the light engine and the channel letter is increased, the useable light in the can is proportionally diminished.  
         [0006]     In view of the foregoing, a general need has been recognized in connection with providing a cost-effective lighting arrangement that employs versatile technology such as fiber optics but improves upon the shortcomings hitherto encountered with such technology.  
       SUMMARY OF THE INVENTION  
       [0007]     Broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, are unique manners of combining the advantages of end-lit and side-lit fibers, or functional equivalents of either, to afford a lighting arrangement that is effective, uniform in appearance, and easy to maintain. Particularly, there is broadly contemplated herein the use of side-lit fibers for distributing light along with one or more end-lit fibers that direct light from a “light engine” to the side-lit fibers. One or more end-lit fibers may preferably be connected to a side-lit fiber at either or both ends of the latter. Multiple side-lit fibers may be arranged linearly to aggregately result in a larger side-lit fiber “complex”, wherein end-lit fibers may feed into either or both ends of-each of the side-lit fibers.  
         [0008]     In summary, one aspect of the invention provides an apparatus for providing illumination, the apparatus comprising: a primary illumination element; and a light provision conduit connected to the primary illumination element; the light provision conduit acting to propagate light towards the primary illumination element at an end of the light provision conduit; the primary illumination element being disposed in accordance with a predetermined pattern; the primary illumination element acting to provide illumination in directions outwardly from the predetermined pattern.  
         [0009]     Furthermore, an additional aspect of the invention provides an apparatus for providing illumination, the apparatus comprising: a light engine element; a primary illumination element; and a light provision conduit interposed between the light engine element and the primary illumination element; the light provision conduit acting to propagate light towards the primary illumination element at an end of the light provision conduit; the primary illumination element being disposed in accordance with a predetermined pattern; the primary illumination element acting to provide illumination in directions outwardly from the predetermined pattern. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  shows a channel letter assembly with constituent components.  
         [0011]      FIG. 2  is a side cross-sectional view of a channel letter assembly with a light engine.  
         [0012]      FIG. 3  shows details of a light engine from  FIG. 2 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]     For a better understanding of the present invention, together with other and further features and advantages thereof, reference is made to the following description, taken in conjunction with the accompanying drawings, and the scope of the invention will be pointed out in the appended claims.  
         [0014]     It will be readily understood that the components of the present invention, as generally described and illustrated in the Figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the apparatus, system, and method of the present invention, as represented in  FIGS. 1-3 , is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention.  
         [0015]     Reference throughout this specification to “one embodiment” or “an embodiment” (or the like) means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, 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.  
         [0016]     Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the 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 aspects of the invention.  
         [0017]     The illustrated embodiments of the invention will be best understood by reference to the drawings, wherein like parts are designated by like numerals or other labels throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the invention as claimed herein.  
         [0018]     In accordance with a preferred embodiment of the present invention, as shown in  FIG. 1 , a channel letter “can”  102 , here in the shape of a letter “C”, is configured to hold a side-lit fiber  104 . Preferably, a light guide  108  in the form of an end-lit fiber will enter :.can  102  through an entry hole  110  to connect to one end of the side-lit fiber  104  via a terminal block  106  (to be described more fully below). As shown, a reflective cap  112  can preferably be provided at the other end of side-lit fiber  104  to reflect light back through the side-lit fiber that has already progressed through side-lit fiber  104 . Alternatively, the reflector cap e could be replaced by a second terminal block similar to  106  into which feeds a second end-lit fiber similar to  108 . The reflective material within the reflector cap  112  is preferably a material with specular reflective properties, such as a highly polished die-cut Aluminum disc.  
         [0019]     By way of sample dimensions, end-lit fiber  108  may have a diameter ranging from 5 to 7 mm while side-lit fiber  112  may have a diameter in the range of 10 mm to 14 mm, or approximately twice the diameter of the end-lit fiber. An example of a suitable end-lit fiber would be the “Super Side Light” fiber produced by Poly Optics Australia Pty Ltd of Burleigh, Qld., Australia.  
         [0020]     Terminal block  106  is preferably configured so as to snugly and efficiently accommodate respective ends of side-lit fiber  104  and end-lit fiber  108  (and thus accommodate the likely mismatch in diameter between fibers  104  and  108 ). Maximal light transmission is accomplished by axially aligning the end-lit and side-lit fiber terminals. Preferably, the fiber ends are cleaved at right angles to the longitudinal axis of light propagation to ensure an optimal butt fit. Terminal block  106  itself is preferably formed from a translucent thermoplastic material such that light can emit from it as well and thus prevent any type of “dead spot” with regard to the aggregate light emanating from can  102 . Essentially any suitable form-fit or interference fit between respective ends of the fibers  104 / 108  and block  106  may be employed. (For instance, an interference fit could employ dimples, or a notch and groove, or any of a wide variety of interference fit connections as commonly known.)  
         [0021]     The block  106  itself can preferably be custom-made for the fibers  104 / 108  in question and in any case can be very easily formed. For instance, block  106  could be embodied by an injection-molded component (formed from resin). Alternatively, it could be formed from an initial block of material that is subsequently cut to length and formed as needed. As but one example among many, McMaster-Carr Supply Co. of Los Angeles provides suitable bars of translucent thermoplastic material for this purpose.  
         [0022]     As contemplated above, one light engine, which feeds into a side-lit fiber  104  via an end-lit fiber  108 , can be provided to illuminate an entire letter as shown in  FIG. 1 . In such a case, the reflector cap  112  helps multiply the effect of this single light engine. Alternatively, reflector cap  112  could be replaced by yet another terminal block which connects to an end-lit fiber emanating from another light engine. Such an arrangement would create a stronger overall light output than that shown in  FIG. 1 .  
         [0023]     It is possible to provide an even greater number of end-lit fibers feeding into a side-lit fiber. For instance, a letter such as that shown in  FIG. 1  could be lit by a plurality of segments of side-lit fiber that are linearly arranged end-to-end with respect to one another to form the full letter. Terminal blocks at one or more ends of each of such segments can interconnect each such segment with a corresponding end-lit fiber. As with the embodiment shown in  FIG. 1 , each such segment can have a reflector cap at a second end of the segment, or could be provided alternatively with another terminal block which interconnects with yet another end-lit fiber. It will be appreciated that in any of the “multiple segment” scenarios just described, a greater number of segments will typically result in a greater overall light output for the letter (or other larger element) in question; thus, particularly large sign assemblies may well warrant a “multiple segment” approach.  
         [0024]      FIG. 2  shows a side cross-sectional view of a channel letter arrangement in accordance with a possible application. As shown, channel letter face  222  (typically a plastic face on a channel letter can such as that indicated at  102  in  FIG. 1 ) encases a side-lit fiber  204  as discussed above. As also discussed above, an end-lit fiber  208  preferably feeds into a terminal block  206  at one end of the side-lit fiber  204 . In the application shown in  FIG. 2 , a wall  214  intervenes between the light engine  218  and channel letter assembly. Preferably, end-lit fiber  208  interconnects light engine  218  and side-lit fiber  204  (via terminal block  206 ) through a conduit or bore  216  in wall  214  (terminating at hole  210 ). Indicated at  220  is a suitable power source for light engine  218 .  
         [0025]      FIG. 3  shows details of a light engine that may be employed as the light engine shown at  218  in  FIG. 2 , though of course a very wide variety of substitutes are possible. As shown, enclosure  219  of the light engine assembly  218  includes therewith a pair of lens holders i, out of one of which an end-lit fiber  208  is shown to extend. A suitable light source such as a high-flux LED h is configured to emit light into a collimating lens g and then into end-lit fiber  208 . An O-ring f may be employed to secure the collimating lens assembly g within the lens holder i and to provide ingress protection from moisture and other contaminants. As is well-known, an aluminum slab  224  may be provided to support the lens holders i, and a heat sink  226  may be provided under slab  224 . Components f, g and h are preferably centered about an optical axis j (shown on the left). Further, on each side, a water-tight gland a is preferably provided to surround and seal an end-lit fiber such as  208  as the latter enters the enclosure  219 .  
         [0026]     It should be understood that the embodiments of the present invention, as broadly described and contemplated herein, need not be restricted to channel letter or light box arrangements. In point of fact, there are a very wide variety of alternative applications, such as the use of straight strands of fiber optic cable, preferably in an appropriate channel, box or other mounting medium, in illuminating spaces that are normally dark and difficult to access, such as the interior of fluid storage tanks, underneath countertops, bookshelves, and in a very wide variety of other possible locations. Essentially, any application is conceivable where a passive optical system is useful: for visual effect; for anywhere that one might need to avoid heat caused by a lamp; anywhere one might need to avoid sparks caused by an electrical circuit.  
         [0027]     While the use of optical fibers is specifically contemplated hereinabove, analogously functioning materials may of course be substituted. For instance, Bridgestone produces a Luxaura™ PMMA thermoplastic rod which can be cut to length and used in the same manner as side-lit fibers as discussed hereinabove. This rod, like all light guides, operates on the principle of Total Internal Reflection (TIR), having a core, and a cladding with a lower index of refraction. It also has a co-extruded light-extracting reflector. Another alternative material would be translucent acrylic sheets as often used in the signage industry for shallow back-lit signs; the “Prismex™” product of Lucite International is a good example.  
         [0028]     If not otherwise stated herein, it is to be assumed that all patents, patent applications, patent publications and other publications (including web-based publications) mentioned and cited herein are hereby fully incorporated by reference herein as if set forth in their entirety herein.  
         [0029]     Although illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various other changes and modifications may be affected therein by one skilled in the art without departing from the, scope or spirit of the invention.