Patent Publication Number: US-6991350-B2

Title: Housing for an LED fixture and soffit lighting system utilizing the same

Description:
FIELD OF THE INVENTION 
   The present invention relates to housings for decorative lighting and for the application of these housings. In particular the present invention relates to discrete lighting fixtures for LED light sources, and the application thereof. 
   BACKGROUND TO THE INVENTION 
   Landscape lighting has become a specialized field in recent years in which experts require various types of lights in order to create the effect they are seeking. There are two primary purposes for landscape lighting: safety and beauty. Lighting can enhance the safety of a building by illuminating walkways and entrance ways, ensuring that a person can see obstacles, and removing some hiding areas for intruders. 
   Lighting further enhances the beauty of a building. Without lighting, a home and all of its architectural and landscaping details fade into the night. Lighting allows people to enjoy a building&#39;s features and landscaping even into the evening hours. Properly placed lighting adds curb appeal and creates a welcoming atmosphere for a home. 
   Various lighting systems exist, including post lights, lights mounted on walls around or over doorways. One such system is taught by U.S. Pat. No. 5,599,091 to Kira. These type of systems teach the use of incandescent or halogen illumination for walkways, doorways, or architectural or landscape features. However, these types of lighting systems have several drawbacks. 
   Lighting systems first need to be durable. A lighting system needs to be able to withstand years of variable weather, ranging from blistering heat to freezing cold, from high UV exposure from sunshine to moisture exposure from rain, snow and sleet. A quality lighting system cannot fail after only a few years due to materials. 
   Further, the use of incandescent or halogen bulbs also is problematic. These bulbs generate a significant amount of heat, restricting the type and size of the casing around these bulbs. Further, these bulbs have a relatively short life span, necessitating replacement. This can be both time consuming and dangerous if such lights are mounted in an elevated position such as on the soffit of a building. 
   Other lights which are within the art include recessed light fixtures that fit within a soffit of a building. An example of such a system is taught by U.S. Pat. No. 6,000,818 to Calouri. The problem with these type of systems is that they are not adjustable in the area which they light. These systems point straight down and create a cone of light under the fixture. 
   For landscape lighting a fixture should be adjustable. This first allows landscape or architectural features to be highlighted. Secondly, as elements change, such as when trees or bushes grow, it is desirable to adjust the lighting of these elements. The shortcoming of existing soffit solutions is that they do not allow this flexibility. 
   A third desirable feature of landscape lighting systems is that they be discrete. These systems should not draw attention to themselves during the day. For fixtures such as those illustrated in U.S. Pat. No. 5,999,091 to Kira, their size makes them difficult to hide or affix discretely. 
   Discrete lights are also important at night. A fixture should minimize glowing or drawing attention to itself. The problem with UV resistant plastics is that they transmit light. One possibility for preventing this is the use of an internal coating. However, internal coatings which would come to the inner edge of an outer shroud are more visible during the daytime, making the fixtures less discrete. 
   SUMMARY OF THE INVENTION 
   The present invention seeks to overcome the shortcomings of the prior art by providing a lighting system that can be mounted to soffits, walls or ceilings and that is compact and discrete. The system uses a light emitting diode (LED) light source, allowing smaller casings than landscape lighting currently in the art. The use of an LED further reduces power consumption and increases the longevity of the fixture. 
   The system further provides a shroud that is colored to camouflage the fixture against the soffit, wall or ceiling it is mounted to in order to reduce the visibility of the lighting system during the daytime. The shroud is comprised of durable UV resistant plastic. 
   At night, in order to reduce any glow of translucent shrouds, an inner shroud is provided that absorbs light directed sideways. This inner shroud is made of a dark plastic and has an inner diameter that is smaller than the outer diameter, providing a deep edge at the front of the inner shroud. The dark shroud can be offset from the front of the outer shroud, making it harder to see in the daytime. Also, at night the front of the outer shroud is in shadow of the inner shroud when the LED light source is lit, ensuring minimal glowing of the fixture. 
   The system further provides an illumination system wherein the light can be focused on a particular feature or element of the landscaping. The illumination system can also be redirected to other landscape features or to be more properly directed to a changing landscape feature by its adjustable nature when necessary. 
   The system further provides for heat dissipation to allow brighter, higher powered LEDs to be used. The heat dissipating system removes heat from the LED that might otherwise shorten the LED&#39;s life span an/or its brightness. Lower powered systems may further include a h at dissipation system to provide for manufacturing efficiencies and product consistencies for fixture systems with both low and high powered LEDs. 
   The present invention therefore provides a housing for a light source, said housing comprising: an outer shroud, said outer shroud including an outer surface, a front edge, and a hollow inner surface; and an inner shroud, said inner shroud including a front edge and a concentric bore, said inner shroud fitting concentrically within said inner surface of said outer shroud and said front edge of said inner shroud being offset back from the front edge of said outer shroud; wherein the radius between the outer edge of said concentric bore and the outer edge of said inner shroud shades said front edge of said outer shroud from said light source. 
   The present invention further provides a fixture for illuminating architectural and landscaping features of a property, said fixture comprising: a housing; a light emitting diode affixed within said housing; a power supplying means to provide power to said light emitting diode; and a mounting means for mounting said housing to a building; wherein said light emitting diode provides illumination for the architectural and landscaping features of the property. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In drawings which illustrate by way of example only a preferred embodiment of the invention, 
       FIG. 1  is a front perspective view of a lighting fixture of the present lighting system; 
       FIG. 2  is cross-sectional view of the lighting fixture of  FIG. 1 ; 
       FIG. 3  is an exploded view of the lighting fixture of  FIG. 1 ; 
       FIG. 4  is a front perspective view of an alternate lighting fixture of the present lighting system; 
       FIG. 5  is cross-sectional view of the lighting fixture of  FIG. 4 ; 
       FIG. 6  is an exploded view of the lighting fixture of  FIG. 4 ; 
       FIG. 7  is a front perspective view of a further lighting fixture of the present lighting system; 
       FIG. 8  is cross-sectional view of the lighting fixture of  FIG. 7 ; and 
       FIG. 9  is an exploded view of the lighting fixture of FIG.  7 . 
   

   DETAILED DESCRIPTION OF THE DRAWINGS 
   Reference is now made to the drawings.  FIGS. 1  to  3  show a fixture  1  of the present invention. Fixture  1  is adapted to be hung from a soffit, ceiling or wall of a building and to be concealed both during the day and at night. 
   While fixture  1  can be used indoors, fixture  1  is primarily adapted to be used outdoors. Fixture  1  is therefore comprised of durable materials that can withstand the extremes of being in an outdoor environment, as described below. 
   Fixture  1  includes an outer shroud  10  which presents the external face of fixture  1 . Outer shroud  10  is preferably comprised of plastic, and in particular is chosen from plastics that have a durability of over 20 years in an external environment. Such plastics are adapted for both extreme cold and heat, and are resistant to ultra-violet (UV) radiation. One suitable plastic used by the inventor is made by Cyro Industries under the name Acrylite®. 
   Outer shroud  10  is preferably a hollow cylindrical shape, although other shapes may be used. 
   In operation, the color of outer shroud  10  is preferably chosen to match the soffit, wall or ceiling color on which fixture  1  is being mounted. This color matching, along with the small size of outer shroud  10  allows fixture  1  to be camouflaged against the soffit, making it difficult to see during the day. 
   One problem with outer shroud  10  is that plastics that are durable and UV resistant are not completely opaque. These plastics in fact are somewhat translucent, and conduct light when a portion of the outer shroud  10  is illuminated from the inside. In order to overcome this disadvantage fixture  1  further includes an inner shroud  20 . 
   Inner shroud  20  is preferably comprised of a dark, light absorbing plastic that is adapted to concentrically abut the inner surface of outer shroud  10 . A tight fit and/or the use of various possible sealing techniques minimizes the possibility of water seeping between the two surfaces and freezing, thus causing damage to inner shroud  20  or outer shroud  10 . These sealing techniques can further hold inner shroud  20  within outer shroud  10 . Alternatively, a set screw may be introduced between inner shroud  20  and outer shroud  10  to hold inner shroud  20  in a proper position. 
   As shown in  FIGS. 1 and 2 , when installed the front edge  22  of inner shroud  20  is offset back from the front edge  12  of outer shroud  10 . This configuration presents several advantages. By using a light absorbing dark plastic material outer shroud  10  will not be illuminated, thus preventing outer shroud  10  from glowing. This makes fixture  1  more difficult to see at night, creating a better aesthetic impression. 
   Moreover, if inner shroud front edge  22  extended to the front edge  12  of outer shroud  10  it would be visible during the day. The dark color of inner shroud  20  would then be highlighted by a lighter colored outer shroud  10 , producing an undesired visibility. By offsetting front edge  22  of inner shroud  20  from front edge  12  the visibility of inner shroud  20  is reduced. 
   An additional advantage of using a plastic inner shroud  20  is that the thickness of the inner shroud  20  protects outer shroud  10  from being illuminated. Since inner shroud  20  is offset from front edge  12  of outer shroud  10 , the possibility exists that a light source would still illuminate front edge  12 , making fixture  1  more visible at night. This is clearly undesirable. The thickness of plastic in inner shroud  20  is chosen along with the angle of incidence of the light, resulting in the exposed inner surface of front edge  12  being principally in the shadow of inner shroud  20 , minimizing illumination of the front edge  12  of inner shroud  20 . 
   In fixture  1 , the rear edge  24  of inner shroud  20  is preferably spaced from the inner rear surface  14  of the outer shroud  14 . This provides an area into which a high quality exterior grade sealant such as silicon can be injected, allowing superior moisture sealing. One such sealant is GE Silicone II™. 
   Inner shroud  20  is further provided with a lip  26  which projects inwardly from inner shroud  20  and is preferably located at point forward of the midpoint between rear edge  24  and front edge  22  of inner shroud  20 . Inner bore  28  of lip  26  is adapted to receive a light source. 
   The light source  30  of the present invention is preferably a light emitting diode (LED). The advantage of this type of light source is its efficiency, life and low heat properties. The use of a plastic inner shroud  20  necessitates that a low heat light source be used. Further, light emitting diodes have a life which can exceed one hundred thousand hours before they need to be replaced. This is advantageous for installations in which fixture  1  is affixed to a soffit or ceiling where replacement of light bulbs would be a difficult and potentially dangerous exercise. 
   The efficiency of an LED source  30  is also advantageous. The power consumption of a light emitting diode is significantly lower than that of an incandescent bulb. For an application such as exterior lighting where the lights will be on for a significant time period each day, the lower cost of operating these lights is an advantage. 
   A further advantage of light emitting diodes is that they provide a saturated color. This is advantageous over incandescent or halogen systems in which a colored lens is placed over the light in order to change the color of the light. This merely filters the light leading to light loss and heat build-up in the light housing. 
   LEDs are well known in the art. They come in a variety of colors, allowing light source  30  to be customized to create a different artistic effect than with only white light which most incandescent bulbs are restricted to. LEDs further can be selected for a particular brightness. 
   In fixture  1 , light source  30  rests within and concentrically to bore  28 . An outer flange on lights source  30  abuts ring  26 , ensuring proper positioning of light source  30 . Light source  30  is held in place by an adhesive such as GE Silicone II™. 
   Cable  40  includes a supply and ground wire, thus proving power to light source  30 . Cable  40  enters outer shroud  10  through an opening in its rear edge  14  and enters inner shroud  20  through its rear opening. 
   By placing a current limiting resistor  60  along wire  40  rather than within fixture  1 , a series of fixtures can be placed in series, reducing the total number of resistors in the system and providing further power efficiency. 
   The configuration of fixture  1  provides a lighting source that, based on the strength of the LED, is recommended for a brightness which is several time brighter than moonlight at ground level from typical projection heights on the soffits of buildings. If a brighter configuration is desired the heat of light source  30  might reduce the life span of light source  30 . Therefore, for brighter configurations, several further components can be added. Reference is now made to  FIGS. 4  to  9 . 
     FIGS. 4  to  6  illustrate fixture  2 . Fixture  2  is an alternative configuration in which light source  30  can be a higher powered and thus brighter light emitting diode. Various similar components between fixture  1  and  2 , such as outer shroud  10  and inner shroud  20  have been similarly numbered. 
   In order to accommodate a higher power light source, a heat dissipation system  50  can be added to fixture  2 . This allows the life of light source  30  to be extended by ensuring that the heat generated by the light source is dissipated. 
   Heat dissipation system  50  includes a heat sink  52  that can be mounted to the back of outer shroud  10 . Heat sinks are well known in the art. Heat sink  52  preferably includes several square inches of exposed surface area for convection cooling. Preferably, one such heat sink is made from an aluminum rod whose outer diameter corresponds with the outer diameter of outer shroud  10 . 
   Connected between heat sink  52  and inner shroud  20  in fixture  2  is a bolt  54 . Bolt  54  serves the dual purpose of attaching heat sink  52  to fixture  2  and as a heat conduit to dissipate heat from light source  30 . 
   Light source  30 , in the heat dissipating embodiment of the present invention, is enclosed within heat spreader  56 . Heat spreader  56  allows the dissipation of heat by surrounding the lower portion of light source  30  with a heat conductive layer. 
   The above configuration thus allows the use of a higher power light source while eliminating some of the drawbacks of such a light source. Specifically heat, which might shorten the life of a light emitting diode, is channelled away from the light source  30  using heat dissipating elements  50 . 
   In all fixtures, a resistor  60  is further included along cable  40  in series with the light source to limit the current to the light source. More than one fixture may be placed in series electrically speaking to conserve power. In all configurations a current limiting device such as resistor  60  is used to set proper bias for the LED device or devices as in the case of a series arrangement. 
   Design should be done such that the current limiting device does not raise the temperature of the LED to the point of compromising LED life or restricting the brightness of the LED. A resistor may be placed outside the fixture mid-span with the cable  40 , as shown in  FIG. 1 , or at the end of the cable  40  where it joins the main feed cable. This removes the undesirable heat from the LED completely which is highly desirable but may result in additional effort and cost for assembly and installation. Also, in the case of higher powered LEDs with higher bias currents, resistors can be in close proximity to the insulation of the electrical wires and can result in a local ambient temperature that is over the specification of the wire&#39;s insulation rating. 
   One alternative for low powered LEDs is to place the resistor within the fixture, as in the cavity of the inner shroud  20  on the lead side of light source  30 . In this configuration, additional thermal relief and moisture resistance is achieved by means of a sealant that can fill this cavity in assembly. 
   If the above alternate heat dissipation method is not adequate, a heat sink  52  as in fixture  2  or in fixture  3 , shown in  FIGS. 7  to  9 , can be used to provide the necessary thermal dissipation. In the case of the higher powered LEDs, a heat sink with integral current limiting device (a preferred choice being the resistor  60 ) is always used as shown in fixture  2 . Heat sink  52  preferably includes a channel  58  to provide a heat dissipating mount for resistor  60 . 
   Fixture  3 , shown in  FIGS. 7  to  9 , may be used as a cosmetically consistent alternative to fixture  1  when used along side of fixture  2 . This utilization may occur even if the current limiting resistor could have adequately been placed in fixture  1  without creating enough heat to be of concern. 
   In fixture  3 , heat sink  52  includes a bore  59 . Inner shroud  59  fits within this bore and can be held in place by bonding or mechanical means. Outer shroud  10  fits over inner shroud  20  and the back of outer shroud  10  abuts heat sink  52 . A set screw may be used to hold outer shroud  10  in place. Also, the gap between outer shroud  10  and heat sink  52  can be sealed using a sealant or a gasket or o-ring. 
   A further element that can be added to any of the fixtures of the present invention is a lens to provide focussing and reduced light loss, as shown in  FIGS. 4  to  6 . Light is emitted from an LED within a specified angle range based on the shape of the LED. When only the internal shroud  20  is used, light which is directed into this internal shroud is lost. If further brightness is required, a lens  65  can be affixed over the light source  30 . This ensures that more light that is directed towards the side walls of fixture  1  is redirected towards the intended target, ensuring brighter illumination. However, some light is still lost, even with a lens, necessitating the inner shroud remain even for this configuration. 
   Lens  65  is held in place using lens collar  70 . Lens collar  70  is made from the same material as outer shroud  10  and is adapted to fit concentrically within the end of outer shroud  10 . The use of lens  65  and lens collar  70  remove some of the camouflaged nature of fixture  1  at night due to the glow created in lens collar  70 , but substitute this for brighter illumination. 
   Various fronts can be placed within the center of lens collar  70 . These include flat glass to reduce exposure to insects and moisture. Diffusers can also be used in an attempt to more evenly distribute light rather than having a central bright spot. 
   In application, fixtures  1 ,  2  or  3  are affixed to a soffit, wall or ceiling using a mounting mechanism  80  that allows the fixture to be pointed in any direction. Mounting mechanism  80  is preferably adapted to hold the position of the fixture through various adverse weather conditions without moving, but is also capable of being adjusted easily. 
   In a preferred embodiment, mounting mechanism  80  comprises a bracket  82 . Bracket  82  preferably has a right angled bend in it, and can be comprised of any suitable rigid material, including aluminum or plastic. 
   Bracket  82  is affixed to fixture  1 ,  2  or  3  through a hinge, which allows pivoting of the fixture. Preferably the hinge comprises a bolt  84 . Bolt  84  is preferably held in place by nut  86 , as in fixtures  1  and  3 , or by threading in heat sink  52 , as in fixture  2 . Bolt  84  can further serve to hold heat sink  52  to inner shroud  20  in fixture  3 , as seen in  FIGS. 6  to  9 . 
   In order to allow rotation, a washer  88  is further added at one end and a resilient “O” ring  90  is added at the other end of fixture  1 . Resilient “O” ring  90  must be durable but provide sufficient frictional grip to prevent fixture  1  from moving once it is in the correct position. The advantage of “O” ring  90  is that finer adjustments are possible than by using a detent system. In decorative lighting applications fractions of a degree can be important and make a difference. 
   Bracket  82  is further mounted to the soffit, wall or ceiling using an affixing means such as a screw. Hole  92  is used for this mounting purpose. 
   Power is supplied to fixture  1  through a power cable. In a preferable embodiment, a timing and power converting unit is located within the building being lit. The timing unit can be used to program when the lights turn on. This can further be supplemented with light level sensors or other means which are known in the art. 
   The power converting unit generally converts the AC power supplied to the building to a DC voltage to be supplied to light source  30 . Alternatives include solar charging of batteries to supply power to light source  30 . 
   In operation, a series of fixtures can be affixed along a soffit of a building, each pointing at a specific element of the landscaping or architecture that the user wishes to highlight. Artistic elements can be enhanced through the use of varied brightness or color. A single cable runs from the power converting unit along the soffit of the house. This cable preferably is the same color as the surrounding soffit material or other background building material and has weather resistant insulation. 
   Various connector schemes as well as permanent soldered and sealed connections are preferably found along the cable to allow wires  40  to be affixed to the common cable, thus providing power to fixtures  1 ,  2  or  3 . 
   The above-described embodiments of the present invention are meant to be illustrative of preferred embodiments and are not intended to limit the scope of the present invention. Also, various modifications, which would be readily apparent to one skilled in the art, are intended to be within the scope of the present invention. The only limitations to the scope of the present invention are set forth in the following claims appended hereto.