Abstract:
A method of designing a modular lighting system comprising determining a length of a lighting fixture, then selecting a plurality of light emitting diode (LED) modules from a selection of standardized sizes. And assembling the modules together with a fixture, so that the modules and the fixture combine to form the determined length. In some embodiments the selecting is done from a group comprising either a 10 inch, a 12 inch or a 4 inch LED module. In some embodiments the determining is in response to a building metric. 
     Also disclosed is a luminaire comprising a hub having a predetermined length; with LED modules, each having a different length, where the lengths of the hub and the modules combined form a standard length as generally used in the building and construction trades. By way of example, these standard lengths could be 12, 16 or 24 inches.

Description:
BACKGROUND 
       [0001]    The present invention relates generally to luminaires and more particularly to a system and method for disposing LED and other light sources onto a luminaire such that the luminaire conforms to a structure&#39;s metrics. 
         [0002]    Lighting fixtures and luminaires are basic lighting devices used in homes, offices and a variety of industrial settings. One criterion when selecting a lighting fixture is that the lighting is visually attractive. Other criteria include low cost and ease of installation, performance, safety and legality. For industrial lighting the cost of a luminaire is more than the cost of the device because industrial lighting generally requires designs to satisfy many of the above listed criteria. For example, lighting in a warehouse may be required to meet minimum light intensity and safety requirements. This entails the use of a lighting designer or architect who would specify the source and type of luminaire desired for the specified task. 
         [0003]    In addition, industrial lighting requires more detailed installation because industrial lighting is often installed as part of a larger design of a factory or workspace. The details of the lighting system must be specified in advance so that pricing, delivery and planning can be properly performed. Also industrial lighting often must meet higher local safety requirements. It is clear that ease of use and lower cost may be effectuated at the design, installation and usage stages of a lighting system. 
         [0004]    Improvements that provide for an easier to design or an easier to install lighting system lower overall lighting costs. In addition, improvements that provide ease of manufacture may provide lower costs because fewer parts may be required and the manufacturer can gain from economies of scale. One area that has improved lighting designs is in the construction and use of light emitting diodes (LEDs) as light sources. With the development of high efficiency and high power LEDs it has become possible to incorporate LEDs in industrial lighting. LEDs are low-voltage lamps, requiring a constant direct current (DC) voltage or current to operate optimally. An individual LED may need 2-4V of DC power and several hundred milliamps (mA) of current. When LEDs are connected in series in an array, higher voltage is required. An LED driver acts as this power supply by converting incoming power to the proper low-voltage DC power required by the LEDs. 
         [0005]    During operation, the LEDs must be protected from line-voltage fluctuations because changes in voltage can produce a disproportional change in current, which in turn changes light output. (LED light output is proportional to current and is rated for a current range. If current exceeds the manufacturer recommendations, the LEDs can become brighter but their light output can degrade at a faster rate due to heat, shortening useful life. Useful life may be defined as the point where light output declines by 30 percent.) The LED driver regulates the current flowing through the LED during operation and protects it from voltage fluctuations. Led drivers are manufactured and sold as modules including one or more LEDs and control circuitry. 
         [0006]    Design of luminaires may require certain physical characteristics because of the location of the luminaire. For example domestic construction often uses wall supports (“studs”) on 16 inch spacing whereas industrial settings may use alternative spacing such as 24 inches. This requires a luminaire system design that comports to the building metrics without excessive costs. 
         [0007]    Accordingly, improvements to LED-based lighting designs that lower costs of manufacture, design or installation are beneficial. 
       SUMMARY 
       [0008]    Disclosed herein is a method of designing a modular lighting system comprising determining a length of a lighting fixture, then selecting a plurality of light emitting diode (LED) modules where the modules may be of differing sizes. And assembling the modules together with a chassis, so that the modules and the chassis combine to form the determined length. In some embodiments the selecting is done from a group comprising a 10 inch, a 12 inch or a 4 inch LED module. 
         [0009]    Also disclosed is a luminaire comprising a chassis having a predetermined length; and at least 2 light emitting diode modules, each having a different length, where the lengths of the fixture and the modules combined form a standard length as generally used in the building and construction trades. By way of example, these standard lengths could be 12, 16 or 24 inches, but may include others. 
         [0010]    The construction and method of operation of the invention, however, together with additional objectives and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  illustrates a schematic diagram of a conventional light emitting diode (LED) module for use in a luminaire. 
           [0012]      FIG. 2  illustrates several luminaires of varying lengths. 
       
    
    
     DESCRIPTION 
       [0013]    Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. 
       Lexicography 
       [0014]    Read this application with the following terms and phrases in their most general form. The general meaning of each of these terms or phrases is illustrative, not in any way limiting. 
         [0015]    The term “standard length” generally refers to the uniform spacing as found in the building and construction industry. One standard length is 16 inches, which is usually specified for the distance between studs on a wall. Other standard lengths include, but are not limited to 12 inches and 24 inches. These standard lengths are often found in the construction of industrial lighting systems because and are used for specifying electrical drops in industrial settings. 
         [0016]    The term “luminaire” generally refers to a lighting fixture complete with the light source or lamp and connection to a power source. A Luminaire may optionally have a reflector for directing the light, an aperture (with or without a lens), the outer shell or housing for lamp alignment and protection, an electrical ballast, if required, However, for purposes of this disclosure, a luminaire may not require every part listed above, but may be comprised of only a portion of the listed components. 
         [0017]    The term “Driver” generally refers to circuitry for operating one or more LEDs. A driver typically acts to adjust the voltage or current to the LED to effectuate a given amount of light. Often drivers are coupled to more sophisticated electronics for control of the LEDs. 
         [0018]    The term “circuit board” generally refers to a mechanical support structure used to hold and electrically connect electronic components using conductive pathways, (or traces), etched from copper sheets laminated onto a non-conductive substrate. Circuit boards are often formed from rigid, fire-retardant material, but may also be formed from flexible materials to allow forming the circuit board to fit a given application. 
         [0019]    The terms “chassis” an “rail” generally refer to a material designed for holding a light source. It may include a reflector to direct the light in a particular pattern. 
       DETAILED DESCRIPTION 
       [0020]      FIG. 1  illustrates a schematic diagram of a conventional light emitting diode (LED) module  100  for use in a luminaire. In the  FIG. 1A , a driver  110  comprised of an integrated circuit controls several LEDs  112 . The driver  110  is connected to a power supply V and a ground G. Circuit elements are connected to the driver  100  depending on the driver  100  manufacturer. In the  FIG. 1  these circuit elements are shown as resisters  16  and capacitor C. The driver is operated by 3 control lines  114 . The signal on the control lines determines the light intensity of the LEDs  112 . 
         [0021]    In operation the driver  110  can dim LEDs by reduction in the forward current, pulse width modulation (PWM) via digital control, or more sophisticated methods. Most dimming drivers operate using the PWM method. With this method, the frequency could range from a hundred modulations per second to as high as hundreds of thousands of modulations per second, so that the LED appears to be continuously lighted without flicker. A benefit of the PWM method is that it enables dimming with minimal color shift in the LED output. 
         [0022]    In the  FIG. 1B , a microprocessor  118  is coupled to the control lines of the driver  110 . By coupling the control lines to a programmable device, more advanced operations of the LED module  100  may be effectuated. For example, by coupling the processor  118  to a network (not shown), control of sets of LED assemblies  100  may be employed. Additionally, advanced controls could be connected to the processor  118  such as occupancy sensors, timers and power saving tools may be used with the LED module  100 . 
         [0023]    An LED module  100  may be effectuated using convention circuit board material including flexible material. The drive and LED are mounted to the circuit board and the circuit board sized to the appropriate dimensions according to a desired application. 
         [0024]    References in the specification to “one embodiment”, “an embodiment”, “an example embodiment”, etc., indicate that the embodiment described may include a particular feature, structure or characteristic, but every embodiment may not necessarily include the particular feature, structure or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one of ordinary skill in the art to effectuate such feature, structure or characteristic in connection with other embodiments whether or not explicitly described. Parts of the description are presented using terminology commonly employed by those of ordinary skill in the art to convey the substance of their work to others of ordinary skill in the art. 
         [0025]    In the  FIG. 2  a first luminaire  210  is shown having two fixtures or hubs  212  and  214 . The hubs  212  and  214  provide for mounting the luminaire chassis (or rail) and may also provide for electrical connections and positioning of a reflector (not shown). Length A is the longitudinal length of each hub  212  and  214 . Disposed on the chassis between the hubs is a circuit board having one or more LED modules, which together comprise an LED module  216 . The LED module  216  is shown having 2 LEDs, but may include more. The number of LEDs on the module may vary depending on the type of LED employed and other considerations. The LED module  216  is mounted to the chassis and electrically isolated from the chassis material. The inventors contemplate a chassis made of suitable material to provide a heat sink for the LEDs, such as aluminum, copper or other metal. One having skill in the art will appreciate that, depending on the LEDs employed, other material may be employed. 
         [0026]    The length of the chassis is B′. The hubs  212  and  214  provide for physically mounting the chassis to a support and for providing electrical power to the luminaire. To effectuate the design of the  FIG. 2 , each hub  212  and  214  would be ½ inch and the length of the chassis would be five inches and the circuit board  216  would be 4 inches. This provides for a 6 inch total length luminaire. 
         [0027]    The total length T of the luminaire  210  is the length of each hub  212  and  214  together with the length of the chassis B′. The total length is shown by T=B′+2A, where B′ is the length of the chassis and A is the length of a hubs. For an example of providing a luminaire of a standard length, the luminaire  210  is formed so that length B is 4 inches and length A is ½ inch and B′ is 5 inches. Together, according to the formula presented herein the total length of the luminaire is 6 inches. 
         [0028]    Luminaire  220  is similar to luminaire  210  except that the length of the LED module is C. By providing an LED module where the length C is 10 inches and the length of the hubs is ½ inch each and the chassis is 11 inches, a luminaire of substantially 12 inches may be formed. A luminaire  220  would be a standard length for use in a lighting system. As discussed above, the standard lengths may depend on the industry and location. 
         [0029]    Luminaire  230  is similar to both luminaire  210  and luminaire  220  except that an LED module having a length D is disposed in series with an LED module having a length C. The LED modules length C and D may each be provided with electrical connections to allow for electrically coupling the LED modules together. Close fitting connectors would allow for LED modules to be sized to fit closely and maintain uniform lengths. By way of example length D could be 12 inches providing the total length for LED modules as 22 inches. This would be mounted on a 23 inch rail, which together with 2 hubs would mount to a building metric having 24 inch centers. 
         [0030]    One having skill in the art will recognize that the LED modules may be made from fixed or flexible material as long as they are capable of mounting to the luminaire chassis. In addition, the hubs would be matched to prove a standard length for the hubs at each end. The standard length would depend on the length of the LED module. LED module lengths are depicted as 4, 10 and 12 inches but other lengths could be fabricated to effectuate a similar result. 
         [0031]    In operation, luminaires of standard lengths could be provided by selecting hubs of a predetermined length, and then providing rails and LED modules in combinations that, when added to the hub length, provide for a total length of the luminaire to be a predetermined amount or a standard length. The examples shown in the  FIG. 2  provide for a 6 inch, a 12 inch and a 24 inch luminaire. One advantage to LED modules of 4, 10 and 12 inches is that in combination luminaire lengths can be fabricated to meet the most common standardized building metrics. This provides economies of scale during manufacturing because fewer, but more standardized, parts may be made. 
         [0032]    During design or installation of a luminaire, a designer would select the length of the luminaire desired based on standard building metrics. A user or computer operated selection program would select the appropriate lengths to effectuate the luminaire such that the length of luminaire supports and the total overall length of the luminaire fall on the studs. By way of example, consider a building having 24 inch stud spacing and requiring 8 feet of a linear luminaire. If a user selected four 24 inch luminaires to effectuate the design, 5 supports would be needed, one on each end and one every 2 feet. These supports must fall exactly on the 24 inch stud. This would require a chassis of 23 inches, a 12 inch LED module and a 10 inch LED module and ½ inch hubs on each end for mounting. 
         [0033]    Alternatively an 8 foot design can be effectuated on a single chassis having a 95 inch length using differing combinations of the same LED module lengths. This could be effectuated using two ½ inch hubs and 94 inches of LED modules. For example seven 12 inch modules and a 10 inch module. 
         [0034]    By providing multiple sections based on standard components selected as described herein, large lengths of luminaires may be constructed and still conform to building matrices. The standard sized components described herein work in combination to effectuate 6 inch, 12 inch, 16 inch, 24 inch and multiples thereof all from the same few components thus accommodating the most common 12 inch, 16 inch and 24 inch building metrics for wall supports. 
         [0035]    The luminaire may be provided as part of a kit where the fixtures and LED modules are provided so that an installer could assemble the luminaire to conform to a requirement. The kit may also include a light rail having reflective properties for operation with the LEDs. 
         [0036]    The above illustration provides many different embodiments or embodiments for implementing different features of the invention. Specific embodiments of components and processes are described to help clarify the invention. These are, of course, merely embodiments and are not intended to limit the invention from that described in the claims. 
         [0037]    Although the invention is illustrated and described herein as embodied in one or more specific examples, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention, as set forth in the following claims.