Patent Publication Number: US-8979303-B2

Title: Light fixture with curved frame

Description:
The application claims the benefit of U.S. Provisional Application No. 61/586,614 filed Jan. 13, 2012. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to exterior vehicle lighting. 
     2. Discussion of the Prior Art 
     Prior art exterior vehicle lighting is limited in the manner by which light is distributed from the light source. For example, one prior art light source comprises one or more lights oriented in a plane and directing light in one direction and relying on diffusers or lenses to distribute light in directions other than the one direction. Based on the above limitations of the prior art, it would be preferable to improve the distribution of light. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a lighting fixture for protecting and mounting an array of light sources such as Light Emitting Diode (LED) modules. The fixture includes a frame with a first surface that arcs or curves with an arc angle of between ten and fifty degrees and an arc length of between about ten to fifteen times the arc height. A plurality of LED modules including a lens and bonnet reflector are each functionally coupled against the first surface to direct a combination refracted and reflected beam pattern, the beam pattern of each LED module having an peak luminous intensity directed substantially normally from the first surface in front of and against which each LED module is functionally coupled. The peak luminous intensity of the combination refracted and reflected beam pattern associated with each LED module has a positive angle with respect to the combination refracted and reflected beam pattern from adjacently located LED modules. 
     The light fixture of the current invention fulfills the objective of producing a plurality of combination refracted and reflected beam patterns associated with each LED module and wherein each of the combination refracted and reflected beam patterns is directed substantially normal to the first surface of the frame behind and adjacent to each LED module. The resulting composite beam pattern comprised of the combination refracted and reflected beam pattern has a substantially uniform luminous intensity at angles within the arc angle of the fixture. 
     Objectives are fulfilled by the invention including the enhanced distribution of light from a combination beam light source without having to use a diffuser or a lens shape that also diminishes the intensity or brightness of a light source as it spreads or distributes light. Accordingly, the present invention is particularly useful in as a spot light that distributes with equal intensity in a radial pattern. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a top view of an embodiment of the invention; 
         FIG. 2  illustrates a front view with a cutaway portion; 
         FIG. 3  illustrates a cross section; 
         FIG. 4  illustrates a cross section with portions specified for detail in  FIGS. 5 &amp; 6 ; and 
         FIG. 5  illustrates detail from the perimeter ridge  11 . 
         FIG. 6  illustrates detail from the backplane trough  133 , respectively. 
     
    
    
     DESCRIPTION OF THE INVENTION AND/OR EMBODIMENTS 
     The invention comprises a curved frame for use as a lighting fixture for protecting and mounting a plurality of light sources on a vehicle or other transportation.  FIG. 1  is a top view of a preferred curvature or arc angle “Θ” of the frame  1 . An exemplary light source using the frame  1  includes an array of distinct light sources such as LED modules  50  oriented to direct and distribute light  20  radially in a semi-circumferential pattern from the frame  1  in the direction of the arc. The LED modules  50  may include at least one LED and at least one other LED module component such as a reflector, an LED driver, an LED lens, or an LED housing. A plurality of thermal fins  11  extend from the back of the curved backplane  131  to dissipate heat from the electronics within the frame  1 . 
     The frame  1  provides both structural support for the LED modules and thermal management. A preferred electronics frame is composed of metal and has a first side with a substantially smooth or planar surface and a second side with fins  111  for heat dissipation.  FIG. 2  illustrates a front view of the frame  1  and the interior surface or curved backplane  131  against which the LED modules are coupled. LED modules are arranged in an array comprising one or more rows of LED modules coupled against the curved backplane  131 . 
       FIG. 3  illustrates a cross section of the curved frame  1 . A curved perimeter ridge  11  extends from either side of the curved backplane  131  for the length of the frame  1  and provides a cavity, channel or recess within which the LED modules are secured and protected. A protective lens (not shown) constructed from a sturdy and abrasion resistant material such as polycarbonate is mechanically coupled to the perimeter ridge  11  and defines a cavity within which the LED control electronics are secured and sets the lens off from the curved frame  1  and the LED modules within cavity defined by the curved backplane  131  and the curved perimeter ridge  11 . The protective lens can be either clear or incorporate one or more lens designs to focus or collimate or diffuse or direct light in a desired direction from the frame  1 . 
     The preferred curved backplane  131  includes a backplane trough  133  defined by at least one surface separated from, and substantially parallel to, the curved backplane  131  surface. The illustrated trough  133  is equidistant from either perimeter ridge  11  but can be offset from the center. The at least one surface of the backplane trough  133  is a biasing surface against which fasteners can bias for securing LED modules or circuit boards to the backplane  131 . As illustrated in  FIG. 3 , the preferred backplane trough  133  as viewed from a cross section resembles a negative image of a “+” or “t” shape and comprises five surfaces substantially parallel to the curved backplane  111  and six surfaces substantially perpendicular to the curved backplane  131 . Nut-type fasteners are slid into the trough from the ends of the frame  1  and oriented to be engaged by bolt or screw type fasteners from a direction substantially perpendicularly to the backplane  131  and engage and bias to secure circuit boards placed against the backplane  111 . 
     As illustrated in the cross sectional view of  FIG. 4 , the perimeter ridge  11  has a ridge height or longitudinal dimension between about one-half and one-fourth, and preferably about one-third of the height of the frame  1 . A perimeter trough  113  is accessible beneath the top edge(s) of the perimeter ridge  11 . As cross section of the perimeter trough  113  illustrated in  FIG. 5  resembles a negative image of a “+” or “t” shape with five surfaces substantially parallel to the curved backplane  111  or top edge of the perimeter ridge  11  and six surfaces substantially perpendicular to the curved backplane  131  and top edges of the perimeter ridge  11 . The preferred perimeter ridge  11  includes an O-ring channel  115  extending substantially perpendicularly from the perimeter ridge  11  towards the interior of the frame  1  and positioned adjacent the top edge of the perimeter ridge  11 . The channel or trough  115  is adapted or sized to receive a rubber gasket or O-ring, which is compressed by the fixture lens mechanically coupled to the perimeter ridge  11  top edges by fasteners biased by the perimeter trough  113 . 
     In one example of use, a plurality of LED modules are securable to the backplane  131  in equal or unequal rows, with equal or unequal numbers of LED modules. In this example, the LED modules each include an LED with encapsulate to refract light into a lambertion pattern and may optionally include a lens suspended above or adhered to the encapsulate to refract light into a refracted beam pattern. A bonnet type reflector is positioned adjacently and above each LED creating a reflected beam into a reflected beam pattern. The bonnet type reflector is a curved concave shape and may be any shape that reflects light into a reflected beam pattern. The combination of the refracted beam pattern and reflected beam pattern from each LED module produces a combination refracted and reflected beam pattern directed away and substantially normally from the curved backplane  131  above or adjacent to which the LED module is positioned and secured. The plurality of LED modules produce a plurality of combination refracted and reflected beam patterns wherein each of the plurality of combination beam patterns is directed substantially normally from the curved backplane  111  above which each LED module is positioned and secured. 
     In another example, the plurality of LED modules omits either or both of the refracting lens or the reflecting lens. Still, the production of a plurality of beam patterns from each LED module is directed substantially normally to the backplane  131  to produce a light direction pattern correlated with the curvature of the backplane  131  of the frame  1 . The beam pattern associated with each LED module creates a positive angle with respect to the beam pattern associated with LED modules adjacently located on the backplane  131 . As a result, the light emitted from each LED module is cast at a positive angle with respect to the light emitted from adjacently located LED modules and the luminous intensity of light emitted from the frame  1  is substantially equivalent within the arc angle of the frame  1 . The composite beam from the LED has a substantially consistent luminous intensity within the arc angle of the frame  1  as compared relative to a light fixture having a non-curved or substantially linear light fixture. 
     The illustrated frame  1  of  FIG. 1  has a preferred arc angle “Θ” of between twenty degrees) (20°) and forty five degrees (45°) and is preferably about thirty six degrees (36°) from one end of the frame  1  to the other. The frame  1  arc length is between about ten to fifteen times the arc height and preferably about twelve to thirteen times the arc height. 
     The electronics frame may be a die cast, die cast module, or made by extruding a radius light having the arc angle desired or extruding a straight or linear metal electronics frame, notching the fins in one or more places (to deter buckling of the metal fins), and bending or curving the frame to the desired curvature. Whether extruded or molded another preferred manner of constructing the frame  1  is by molding or extruding identical frame  1  segments having a curved dimension which are then fastened or secured together at the ends to create a completed frame  1  with the desired frame length and arc angle. 
     End caps  30  are secured to the ends of the frame  1  by inserting fasteners such as screws or bolts through the end caps  30  and into fastener receptacles  117  such as screw holes or threaded bolt apertures. The illustrated embodiment shows the fastener receptacles  117  positioned substantially directly beneath the backplane trough  133  and the perimeter trough  113 . The end caps  30  are a unitary construction that are secured to the frame  1  ends include a mounting pivot such as a bolt extending substantially laterally from the frame and provide a mounting point for coupling the frame  1  to mounting hardware and access for the electrical conductor providing power to the interior of the fixture. To enclose the fixture, the end caps  30  are secured to the frame  1  and the protective lens  40  positioned across the frame  1 . A plurality of longitudinally dimensioned rails (not shown) having a width substantially equivalent to the perimeter ridge are placed on top of the fixture lens and bolt type fasteners inserted into nuts positioned laterally in the perimeter trough  113  to engage the bolt type fasteners. 
     While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of a preferred embodiment should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.