# Patent

## Title
High intensity light-emitting diode luminaire assembly

## Abstract

A low-cost, efficient, high intensity LED luminaire (HILL) assembly for use indoors or outdoors in wet, damp, or dry environments. In various embodiments, the HILL assembly can be powered by a universal AC or a DC electrical supply and can operate in a temperature range from about −40° C. to about +85° C. The HILL assembly can include a lens element comprising one or more concavo-convex lenses; an interchangeable LED module comprising a plurality of LEDs positioned in a LED array; and a heatsink housing containing a power supply for the LEDs. The HILL assembly can optionally comprise a circuit board for the LED array that employs thermal via technology, a lens with a frosted lip for attenuating the light source as seen from an angle, and/or a sensor for sensing an environmental parameter of interest. Driver circuitry and the LEDs are preferably mounted directly on a common circuit board.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to and the benefit of: (i) U.S. provisional patent application Ser. No. 61/570,072, entitled “High Intensity Light-Emitting Diode (LED) Luminaire and Methods for Making Same,” filed Dec. 13, 2011, (ii) Ser. No. 61/712,226, entitled “High Intensity Light-Emitting Diode Luminaire Assembly,” filed Oct. 10, 2012, and (iii) International patent application Serial No. PCT/US2012/069442, filed Dec. 13, 2012, each of which is incorporated herein by reference in its entirety


1. TECHNICAL FIELD
The present invention relates to high intensity light-emitting diode (LED) array technology. The invention further relates high intensity LED luminaires and high intensity LED luminaire (HILL) assemblies and methods for making them.
2. BACKGROUND OF THE INVENTION
High intensity light-emitting diode (LED) array technology is currently used to provide lighting in a wide range of applications in which the user needs high intensity illumination.
One drawback of existing high intensity LED luminaire (HILL) assemblies (also known as high intensity LED light fixtures or high intensity LED light fittings) is poor thermal management, which drastically reduces product lifespan. Extended operation of LEDs at temperatures significantly above ambient is not possible with existing HILL designs, yet such assemblies throw off large amounts of heat which are not adequately dispersed.
Another drawback of existing luminaire or HILL assemblies is their “throw-away” design. Lack of in-field serviceability leads to disposal of the entire luminaire assembly rather than replacing its electronics. This wastes resources, since many components that are still serviceable. Furthermore, existing HILLs lack balanced current control and can be prone to “thermal runaway,” which in turn can cause premature failure of the luminaire and shorten its lifespan.
Another drawback of existing HILLs is off-angle glare: when an overhead luminaire is operating, users at ground level see spikes of light intensity emitted by the luminaire, rather than consistent and even illumination over the entire illuminated field.
Citation or identification of any reference in Section 2, or in any other section of this application, shall not be considered an admission that such reference is available as prior art to the present invention.
3. SUMMARY OF THE INVENTION
A high intensity LED luminaire (HILL) assembly is provided comprising:

    
    
        a LED module comprising:
        
            a LED array comprising a plurality of LEDs positioned in the LED array, and
            a circuit board (also referred to herein as a circuit card),
        
        
        a secondary lens element comprising a plurality of lenses, wherein the plurality of lenses is positioned adjacent to the plurality of LEDs;
        a heatsink; and
        driver circuitry for driving the LEDs in communication (or operatively connected) with the circuit board.
    
    


In one embodiment, the heatsink is a heatsink housing.
In one embodiment, the LED module comprises the secondary lens element.
In another embodiment, the HILL assembly comprises a plurality of LED modules comprising secondary lens elements.
In another embodiment, the plurality of lenses comprises at least two different types of LED lenses.
In another embodiment, the circuit board employs thermal via technology.
In another embodiment, the HILL assembly comprises a lens for attenuating a light source as seen from an angle and for reducing off-angle glare.
In another embodiment, the LED module is removable and/or replaceable from the heatsink or heatsink housing.
In another embodiment, the plurality of LEDs is mounted on the circuit board.
In another embodiment, the plurality of LEDs is arranged in a circular or rectilinear array on the circuit board.
In another embodiment, the driver circuitry is disposed on its own driver circuitry card.
In another embodiment, the driver circuitry is disposed on the circuit board.
In another embodiment, at least one lens of the plurality of lenses is a concavo-convex lens (CCL).
In another embodiment, the plurality of lenses is formed as (or forms or is configured to form) at least one lens matrix.
In another embodiment, the at least one lens matrix can be screwed down on top of its respective LEDs to vary size and shape of a field illuminated by each LED.
In another embodiment, the heatsink or heatsink housing is formed as a single unit.
In another embodiment, the heatsink or heatsink housing comprises a plurality of fins.
In another embodiment, the heatsink or heatsink housing is formed as a single unit and comprises a plurality of fins.
In another embodiment, the circuit board is disposed transversely of the fins at an end of the heatsink or heatsink housing.
In another embodiment, the circuit board is disposed parallel to the fins.
In another embodiment, the HILL assembly comprises a plurality of LED modules.
In another embodiment, the HILL assembly comprises a sensor for sensing and/or providing data relating to the HILL assembly or to environmental parameters.
In another embodiment, the HILL assembly comprises a sealing lens.
In another embodiment, the sealing lens comprises a frosted lip for attenuating a light source as seen from an angle.
In another embodiment, the HILL assembly comprises a power supply attached to the driver circuitry.
In another embodiment, the LEDs are dimmable by pulse width modulation (PWM).
In another embodiment, the LED module has an operational temperature range from about −40° C. to about +80° C.
In another embodiment, the heatsink or heatsink housing is provided with at least one mating feature (e.g., T-slot) for enabling a modular connection with a second LED module and for connecting the circuit card to the heat sink, and the LED module is provided with at least one corresponding mating feature (e.g., T-mating feature).
In another embodiment, the circuit board comprises via technology, wherein the via technology comprises a conductive backing selected from the group consisting of copper and graphene.
In another embodiment, the HILL assembly comprises a DC power supply. In another embodiment, the DC power supply comprises an AC-DC converter for converting incoming AC voltage between 100v and 480v AC to 24v DC operating voltage.
In another embodiment, the driver circuitry comprises feedback circuitry for constantly balancing power input to each of a plurality of LED strings.
In another embodiment, the driver circuitry allows the plurality of LEDs to be continuously operated at operating temperatures up to 80° C. while providing an output of 100 lumens/watt from each LED.
In another embodiment, the heatsink or heatsink housing is a linear, one-piece, finned, metal heatsink.
In another embodiment, the HILL assembly comprises at least one joiner.
In another embodiment, the HILL assembly comprises at least one bracket.
A bracket for a HILL assembly is also provided. In one embodiment, the bracket comprises an extruded aluminum bracket body comprising at least one arm, wherein the bracket body is formed to produce a cavity and wherein the cavity is configured to receive a power supply; and a bracket arm cover for each arm of the bracket body, wherein the bracket body is configured for multiple angular mounting options (wall, ceiling, pendant, etc.).
A method for maintaining a constant LED color temperature and/or a color rendering index in a lighting assembly (e.g., a HILL assembly) is also provided. The method can comprise the steps of using constant drive current, thereby decreasing photon emissions; and varying pulse width modulation (PWM).



4. BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is described herein with reference to the accompanying drawings, in which similar reference characters denote similar elements throughout the several views. It is to be understood that in some instances, various aspects of the invention may be shown exaggerated, enlarged, exploded, or incomplete to facilitate an understanding of the invention.
FIG. 1 is a perspective drawing of a first embodiment of a HILL assembly in accordance with the present invention.
FIG. 2 is an exploded perspective view of the embodiment shown in FIG. 1.
FIG. 3 is a plan view of a lens element comprising a plurality of concavo-convex lenses (CCLs) for use in the first embodiment for flood lighting.
FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 3.
FIG. 5 is a plan view of a LED array for use in the first embodiment.
FIG. 6 is a side view of the LED array shown in FIG. 5.
FIG. 7 is a perspective view of an outer frosted dome lens for use in a low bay application of the first embodiment.
FIG. 8 an exploded perspective view and an assembled view of a LED module (also referred to herein as LED replacement module) in accordance with the present invention comprising a LED array, thermal gaskets, interface plate, a current balancing controller FR4 circuit card, and a power supply connector.
FIGS. 9 and 10 respectively are an end view and a perspective view of a heatsink housing as shown in FIGS. 1 and 2.
FIG. 11 is a side view of the HILL assembly shown in FIGS. 1 and 2 further comprising an ambient light sensor and an occupancy sensor.
FIGS. 12 through 14 are perspective views showing various mounting configurations that can be achieved with the first HILL assembly embodiment shown in FIG. 1.
FIGS. 15 and 16 are perspective views from above and below, respectively, of a second embodiment of a HILL assembly in accordance with the present invention.
FIG. 16a is an enlarged view of the portion of FIG. 16 shown in circle 16a showing the joiner with mating edges.
FIG. 17 is a view like that shown in FIG. 15 showing a portion of one bank of LED lamp assembly cutaway.
FIG. 18 is an enlarged view of the portion of FIG. 17 shown in circle 18.
FIG. 19 is an end view of a finned heatsink.
FIG. 20 is a first exploded perspective view from above of the second embodiment shown in FIG. 15.
FIG. 21 is a second exploded perspective view from below of the second embodiment shown in FIG. 15.
FIG. 22 is a plan view of an idealized 16-lens module in accordance with the present invention.
FIG. 23 is a perspective view of the idealized lens module shown in FIG. 22.
FIG. 24 is a plan view of a modular circuit board assembly in accordance with the present invention.
FIG. 25 is an isometric view of an exemplary multiple-module assembly of HILLs in accordance with the second embodiment shown in FIG. 21.
FIG. 26 is an end view of an exemplary single-module HILL in accordance with the second embodiment shown in FIG. 21.
FIG. 27 is a plan view of a first exemplary embodiment of a 16-lens modular subassembly in accordance with the present invention.
FIG. 28 is a plan view of a second exemplary embodiment of a 16-lens modular subassembly in accordance with the present invention.
FIG. 29 is a plan view of the reverse side of either of the first and second embodiments shown in FIGS. 27 and 28.
FIGS. 30a, 30b, 30c, 30c(1), and FIG. 31 are electrical drawings of LED driver circuitry in accordance with the present invention.



5. DETAILED DESCRIPTION OF THE INVENTION
A high intensity LED luminaire (HILL) assembly (also known in the art as a high intensity LED light fixture, high intensity LED light fitting or LED luminaire) is provided. The HILL assembly can be used indoors or outdoors, and in wet, damp or dry environments. In various embodiments, the HILL can be powered by a universal AC (90-480 VAC, 47-440 Hz) or a DC (12-480 VDC) electrical supply. The operational temperature range for the HILL is from about −40° C. to about +80° C. In a preferred embodiment, the HILL assembly comprises a heatsink, referred to herein as a “heatsink housing,” that serves the dual purpose of functioning as the housing for the HILL assembly and as the heatsink for the HILL assembly.
A HILL assembly in accordance with a first embodiment of the present invention can comprise a LED module that is replaceable (or exchangeable or interchangeable) having a plurality of LEDs disposed in a LED array; an array of concavo-convex lenses (CCLs, also known in the art as “concave meniscus” lenses) disposed adjacent to the LED array; a thermal insulator; a heatsink housing; a power supply and associated circuitry; and a circuit board for controlling the LED array by thermal via technology. The LEDs are mounted directly on the circuit board. A first embodiment HILL assembly is well adapted for use, for example, as a floodlight, spotlight, worklight, or hand-held flashlight.
In a second embodiment, the LEDs are arranged in a circular or rectilinear modular array. Modules in the modular array may be ganged together into larger units for use in, for example, overhead room lighting, desk lighting, street lighting, or stadium lighting. Lenses can be adjustable to vary the size and shape of the field illuminated by each LED. In certain embodiment, the power supply driving circuitry can be positioned or mounted directly on the circuit board.
In various embodiments, the HILL assembly can be used for lighting indoor or outdoor areas or for flood lighting. It can be used in high bay or low bay applications. It will be apparent to the skilled artisan that the HILL assembly has many uses for illuminating commercial or industrial settings, but can also be used in residential settings. The commercial or industrial settings in which the HILL assembly can be used can include, but are not limited to, offices, manufacturing facilities, warehouses, parking garages, ball parks, stadiums, and storage areas.
For clarity of disclosure, and not by way of limitation, the detailed description of the invention is divided into the subsections set forth below.
5.1. High Intensity LED Luminaire (HILL) Assembly—First Embodiment
Referring now to FIGS. 1-16, a first embodiment 10 of a HILL assembly in accordance with the present invention comprises at least a secondary lens element 12 comprising a plurality of CCLs 14; a LED module 16, comprising a plurality of LEDs 18 equal in number to the number of CCLs 14, positioned in a first LED array 20; a heatsink (also referred to herein as a heatsink housing) 22; and a power supply 24 disposed within heatsink housing 22. Embodiment 10 further comprises a first O-ring 28; first and second thermal gaskets 30; an interface plate 32; a second O-ring 34 for sealing heatsink housing 22 at the front end; a third O-ring 36 for sealing heatsink housing 22 at the rear end; a back plate 38; a junction box 40; and sealing gaskets 42.
Lens Element
HILL assembly 10 comprises a single secondary lens element 12 (FIGS. 2-3) with one or more CCLs 14 integrated into the lens element. Lens element 12 is also referred to herein as a secondary lens, because the primary lens is a part of the actual LED chip itself. Lens element 12 is preferably made of injection molded plastic, and more preferably, a high temperature acrylic. Other materials, such as borosilicate glass or an optical grade polyycarbonate, can also be used. In first embodiment 10, lens element 12 can comprise a plurality of CCLs 14 (in this embodiment, 36 in number, see FIGS. 1-3) integrated into a singular lens element. As shown in FIG. 4, the concave lens surface 25 of each CCL 14, in combination with the convex lens surface 26 of the CCL, creates wide dispersion optics. After assembly of embodiment 10, each LED 18 is positioned within the concavity of one of the concave surfaces 24 when the lens element 12 is positioned on or attached to the LED array 20 (FIGS. 4-6). In some embodiments, the outer edges 19 of lens element 12 (FIGS. 3-4) can be frosted to reduce off-angle glare.
FIG. 7 shows a perspective view of a different embodiment of a secondary lens element 12A for use in a low bay application. FIG. 7 contains one or more CCLs 14 integrated into the lens element. Secondary lens element 12A comprises a hexagonal lens 14A that is used to make a more uniform distribution of light on the ground for individual LEDs in LED array 20.
LED Array
HILL assembly 10 comprises a LED array 20 comprising a plurality of LEDs 18 positioned in the array (see FIGS. 2, 5 and 6). Any suitable LED or plurality of LEDs known in the art can be used in the LED array 20. Each of the LED elements 18 comprises a primary lens.
HILL assembly 10 also comprises one or more securing screws 44 (FIGS. 5 and 8) or any other suitable securing fastener, adhesive, clamp, spring pin, or tensioning device that secures the LED array 20 in place. In first embodiment 10, a plurality of screws 44 (a plurality of 10 screws in the embodiment illustrated in FIGS. 5 and 8) are used to secure the various components of the HILL assembly, including the LED array 20, to interface plate 32 (see FIGS. 2 and 8). In a preferred embodiment, the LED array 20 is a component of a LED module 16 ((also referred to herein as a LED “replaceable” or “replacement” module; FIGS. 2 and 8), which can be removed in the field (i.e., where it is installed) through removal of the securing screws 44. This enables the LED module 16 comprising the LED array 20 to be exchanged, interchanged or replaced as desired by the user.
The LED array 20 comprises a circuit board or card 46 (FIG. 5) for controlling the LED array. Preferably, the circuit card 46 is a FR4 circuit board, which is a low-cost fiberglass reinforced epoxy laminate known in the art that is flame retardant. Although metal clad circuit cards known in the art, such as metal core printed circuit boards (MCPCB) can also be used, their use is less preferred, since they have a much greater cost than FR4 circuit boards. In a preferred embodiment, circuit board 46 employs FR4 with thermal via technology to provide a low cost circuit board that performs thermally equivalent or better than a metal clad circuit board. Incorporating thermal vias into board design is well known in the art, and mitigates thermal issues by lowering the thermal resistance of the circuit card itself, (see, e.g., Cree, Inc. (2010), Optimizing PCB Thermal Performance for Cree® XLamp® LEDs, Technical Article CLD-AP37 REV 1, Cree, Inc., 4600 Silicon Drive, Durham, N.C. 27703, available at http://www.cree.com/products/pdf/XLamp_PCB_Thermal.pdf (last visited Dec. 13, 2011); IPC 7093: Design and Assembly Process Implementation for Bottom Termination SMT Components ISBN 1-580986-90-0, available for purchase at http://www.ipc.org, Table of Contents available free at http://www.ipc.org/TOC/IPC-7093.pdf (last visited Dec. 13, 2011)).
The LED array 20 preferably comprises parallel strings of LEDs 18, which arrangement confers several advantages. First, this allows for graceful degradation as the array ages. For example, in an embodiment with four parallel strings of LEDs, two of the four strings can fail and the light will still provide the rated lumen output. Second, the LED array does not experience hot spots that reduce LED lifespan. By balancing the current through each string to be within 1% of one another, the LED array runs at a uniform temperature. Hot spots form on a LED array when designs use parallel strings without current balancing. As the array powers up, most of the current travels down the string with the lowest voltage potential. Since not all LEDs are created equal, this will happen. When a single string uses more current than the other strings, those LEDs heat up faster than the others. As the string heats up, the LEDs' voltage potential drops, which in turn causes the LEDs to consume more current from the cooler strings. This effect is known in the art as “thermal runaway” and causes LED arrays to fail prematurely.
In contrast to existing HILL assemblies that have LED arrays either permanently bonded to the heatsink housing 22 or connected through use of a thermal paste, a HILL assembly 10 in accordance with the present invention comprises a LED module 18 comprising a LED array 20 that is a removable and/or exchangeable component and not a permanently installed component of the HILL assembly. The LED array 20 is preferably a component of a LED module 18, but can also be a separate, exchangeable component within the scope of the present invention. Preferably, the LED module 18 comprises pre-installed thermal gaskets or pads 30, so that the end user does not have to apply any thermal paste (which is a tedious, delicate process) when exchanging or replacing the LED module. When installed, the LED module 18 is thermally in contact with heatsink housing 22, which is a high-efficiency finned, thermal radiator, so that heat is dispersed from the module via the heatsink. The LED module 18 is mounted on and removed from the heatsink housing 22 via securing screws 48 (FIG. 2) or other suitable fasteners known in the art, which can, for example, be threadedly received in bores 50 (FIG. 9). The LED module 18 is operably connected electrically through preferably one (preferably keyed) power supply connector (or single connection plug) 52 (FIG. 8) that is attached to interface plate 32 via screws 54 (FIG. 8). In another embodiment, a T-slot connection can be used for operably connecting LED modules.
Heatsink or Heatsink Housing
HILL assembly 10 can comprise a heatsink that also functions as a heatsink housing 22 (FIGS. 2, 9 and 10) that is an open-die, finned metal extrusion formed preferably of an aluminum alloy. It will be recognized by the skilled artisan that other designs known in the art can be used, including but not limited to die castings and split extrusions. The open-die finned extrusion design is preferably used, as it offers a good combination of low price and high performance. Prior art luminaires typically have heatsink bodies that comprise two halves that are bolted or bonded together to form the heatsink. By contrast, the open-die heatsink is one piece, which has numerous benefits (i.e. low cost of assembly, sealing potential, etc.).
Thermal extrusion of the heatsink housing 22 can be used for efficient thermal management. The finned design generates a large surface area over a small length, effectively pulling heat away from the LED components. Additionally, the open cavity 56 of the heatsink housing serves as the housing for internal components, comprising at least one power supply 24. In various embodiments, the open cavity 56 can house a plurality of power supplies.
Heatsink housing 22 comprises a groove 23 (FIG. 9) surrounding the openings of cavity 56 at each end of the housing. An O-ring 34, 36 (e.g., an elastomeric O-ring) is disposed in each groove 23 for sealing cavity 56 by engaging interface plate 32 and back plate 38, respectively (FIG. 2).
Heatsink housing 22 can also comprise fins 62 (FIGS. 2, 9 and 10). In certain embodiments, the fins 62 are capable of multi-angle positioning. In another embodiment, the fins can be longitudinal. In other embodiments, the fins can be arranged transversely or radially.
In certain embodiments, the heatsink housing is waterproof and/or submersible.
In another embodiment, the mounting bracket 60 is capable of multi-angle positioning.
Components for Positioning and Reducing Off-Angle Glare
Prior art luminaires reduce off-angle glare through the addition of a spun metal or refractive plastic shield, which is an additional cost. These shields are relatively large and totally block off-angle glare but do not block the dispersion of the light source, thus wasting off-angle light output of the device.
The secondary lens 12 of the first embodiment of the HILL assembly 10 can comprise a frosted lip 19 (FIG. 4) that can be integral to the secondary lens element 12 that serves to partially attenuate the light source as seen from an angle. The cost of integrating this frosted lip 19 into the secondary lens is negligible and can be done, for example, as part of the injection molding process for forming lens element 12.
In another embodiment, the HILL assembly can comprise a mounting bracket 60 (FIG. 2) or any other mounting system known in the art for mounting or securing a luminaire or other lighting element. Other suitable mounting brackets for luminaires are well known in the art. In specific embodiments, the mounting bracket or system can swivel, pivot or provide multi-positioning of the HILL assembly.
As a single fixture, HILL assembly 10 supports free hanging, ceiling, wall, stanchion, and pendant mounting and can optionally comprise a sensor for sensing an environmental parameter of interest, such as an ambient light sensor 64 and/or an occupancy sensor 66 (FIG. 11). Such sensors are well known in the art and commercially available. As will be apparent to the skilled practitioner, such optional components can be installed in a number of suitable configurations for sensing an environmental parameter of interest.
For example, in one embodiment, the ambient light sensor 64 has the ability to generate a user-defined light output profile, as described further below, based on user defined schedules or personnel detection and ambient light measuring. Light output is adjusted based on currently available light, to save the user energy by not duplicating light.
In another embodiment, the occupancy sensor 66 turns the light on/off based on user-defined time intervals.
Because HILL assembly 10 has a brick-like design that supports multi-module ganging or stacking, a single HILL assembly 10 can be ganged with other like fixtures to make, e.g., a spot light 68 (FIG. 12), arena/stadium light 70 (FIG. 14), or a linear fixture for wider angle lighting 72 (FIG. 13). By employing a modular design for HILL assembly 10 and using industry standard open interfaces, the design is flexible and upgradeable.
Because HILL assembly 10 has instant on/off capabilities, it can be used in power management schemes to generate user-defined light output profiles based on user-defined schedules or personnel detection and ambient light measuring. HILL assembly 10 can be used to generate light output based on detection of currently available light (e.g., with optional ambient light sensor 66) and to save the user energy by not duplicating light. In addition, in embodiments in which an occupancy sensor installed, HILL assembly 10 can detect, and be used in, power management schemes that switch the light on or off based on user-defined time intervals.
In one embodiment, HILL assembly 10 can predict or indicate how much time is left on the light until the lumen output decays below the L70 level (70% of lumen output at time=0 hours).
In another embodiment, HILL assembly 10 can comprise a programmable timer or timing function. Such programmable timers or timing functions are well known in the art.
Table 1 presents ranges of dimensions for various elements of HILL assembly 10, as well as the dimensions of one preferred embodiment. It will be apparent to the skilled artisan that other suitable dimensions can be easily determined for the components of the HILL listed below, as well as for other components described herein.










TABLE 1








Length (in)
Width (in)
Height (in) 
















Part
Preferred
Max
Min
Preferred
Max
Min
Preferred
Max
Min



















Secondary
7
24
0.5
7
24
0.5
0.88
6
0.1


Lens 12











LED 
6.15
24
0.25
6.15
48
0.25
0.06
0.25
0.01


Array 20











LED
7
24
0.25
7
48
0.25
0.95
6
0.1


Module 16











Heatsink
7
14
0.5
7
14
0.5
11
24
0.1


22











Mounting
8.17
48
0
7.45
48
0
2
6
0


Bracket 60









5.2. High Intensity LED Luminaire (HILL) Assembly—Second Embodiment
A HILL assembly is also provided that is based on a modular design. In various embodiments, the HILL assembly can comprise modular lensing provided by, e.g., a lens matrix, a plurality of LED modules or modular LED arrays, joiner brackets that allow for modularity and custom angular positioning of light output, modular heatsink housing(s) and high power modular circuits (that can operate, for example, at high temperatures).
The modular lensing allows for mixing and matching of distribution patterns, which can provide precise, including but not limited to custom, optical controls.
The LED modules or modular LED arrays can have a shared cover design that allows for stacking or joining of multiple modules without the need for fasteners. An advantage of this design is that it does not interfere with the function of the heatsink. The design can allow heat to be pulled with convectional heat transfer.
The cover can also allow for modules to be attached by a joiner bracket as separate units with the cover holding them together. In a specific embodiment, a power supply can be positioned in the middle of such a modular arrangement.
Referring now to FIGS. 15-31, a second embodiment 110 of a HILL assembly in accordance with the present invention is shown. FIGS. 15 and 16 are perspective views from above and below, respectively, of this second embodiment.
HILL assembly 110 comprises a linear, one-piece, finned, metal heatsink housing 122 formed preferably by extrusion of an aluminum alloy (see FIGS. 18-21). Heatsink housing 122 forms the structural frame of assembly 110 and comprises several features that permit attachment of essentially all the other components of assembly 110, as described below.
The HILL assembly can be thermally optimized for heat transfer through gable and ridge vent thermal optimization.
A plurality of formed channels 124 receive a plurality of screws 126 that secure end cap 128 (also referred to herein as gable end cap) to heatsink 122, as shown in FIGS. 19 and 20. End cap 128 preferably includes at least one opening 129 (FIG. 20) as an intake for convectional cooling air for the fins in heatsink 122. The aspect ratio of the end cap 128 allows for a vortex to drive heat from the finned region of heatsink housing 122 and allows for driving the LEDS at higher currents than in the prior art to yield higher light output, as described in more detail below. The heatsink housing 122 can have, for example, two slits cut to increase airflow, therefore reducing the temperature of the HILL assembly.
A plurality of mating features, e.g., T-slots 130 can receive mating features (e.g., T-mating features) 132 extending from LED module (also referred to herein as LED subassembly) 134, as shown in FIGS. 18, 21, and 26, providing secure mounting and thermal connection of LED module 134 to heatsink housing 122. The use of T-slots increases the efficiency of the HILL assembly, and allows, for example, for mixing LED arrays together on a common track.
Opposed lips 136 receive opposed edges of a sealing lens 137, protectively enclosing LED module 134, and in certain embodiments, rendering it waterproof. In one embodiment, the sealing lens can be made of a transparent thermoplastic such as poly(methyl methacrylate) (PMMA).
A joiner (or “joiner bracket”) 140 is also provided. Outer beaded fins 138 can receive mating edges of the joiner 140 in either a single-module HILL assembly, as shown in FIG. 26, or optionally in a multiple-module HILL assembly. In one embodiment, this joiner is configured to allow for angular positioning to direct light output to meet specific needs.
In one embodiment, a HILL assembly module 142 can comprise a heatsink housing 122, a LED module 134, and a sealing lens 137. Such a HILL assembly module 142 may be employed singly or ganged in a wide variety of configurations determined by lighting requirements and space. For example, a single module assembly can form a desk lamp or under-cabinet kitchen lamp; a double module assembly such as is shown in FIGS. 15 and 16, can be useful as an overhead shoplight or for general overhead illumination by ceiling installation; and larger still assemblies, such as 16-module assembly 144 shown in FIG. 25, can be useful for wide area floodlighting as in stadiums or arenas. Referring to FIG. 20, to make the HILL assembly modular, a joiner 140 is used to fasten or connect heatsink housings together.
A bracket arm 148 is connected to either the endcap or the joiner 140 on each side of the HILL assembly. The bracket arms 148 can contain or enclose the wiring for the power supply 150 and connect to each side of the power supply casing 146. A bracket cover 149 can cover the bracket arm. Inside the casing 146, at least one DC power supply 150, and in a specific embodiment, two DC power supplies 150, can be attached. The power supply casing permits cooling of the power supply 150.
Referring now to FIGS. 21 through 24, in a presently-preferred embodiment, each HILL assembly module 142 comprises two LED modules 134 disposed end-to-end (shown for clarity without sealing lens 137). To assemble HILL assembly module 142, the T-features 132 of each LED module are simply entered into the mating T-slots 130 in heatsink housing 122.
The HILL assembly can have on-board “string” control and current sharing, i.e., constant on-time current control. Referring now to FIGS. 24-31a-c, each LED module 134 can comprise a circuit board 160 upon which are mounted 64 LEDs 162 arranged in four rows of 16 LEDs each. Preferably, the LEDs 162 in each row are wired in series and the rows 164, also referred to herein as “strings”, are wired in parallel. Circuitry 166 provides constant current to the LEDs such that if one LED fails, the circuit auto-adjusts to provide more current to the remaining LEDs, thus restoring total light output. HILL assembly module 142 includes a power supply 150 (FIG. 17) that includes a DC-DC converter that can downstep any incoming voltage from up to 390v down to 12v operating voltage. Such a low voltage step-down converter enables high efficiency of the HILL assembly.
Circuitry 166 for driving the LEDs 162 is mounted directly on circuit board 160, allowing the constant current feature just described, and is connected to first and second multi-prong connectors 168a, 168b at opposite ends of circuit board 160, allowing connection to adjacent modules 134.
Because circuitry 166 is designed specifically for these applications and is not bought off-the-shelf, circuitry 166 can be formed, in one embodiment, as an integral element of circuit board 160. This results in greatly increased electrical efficiency of 100 lumens/watt, whereas prior art systems typically operate in the range of 80 lumens/watt. Because the light output is greater, there is less waste electrical energy and less heat generated, e.g., thermal density is reduced. This permits LEDs 162 to run continuously at only 80° C. or lower, whereas prior art systems being driven at such high light outputs must run at greater than 100° C. and are therefore prone to thermal runaway and failure.
Because circuitry 166 can operate at constant current, the power flowing to the individual LED strings 164 is balanced, preventing thermal runaway. Referring to FIG. 30, LED driver 180 (LM3464) includes a feedback loop that continuously balances power feed to minimize temperature on each LED string 164.
The HILL assembly can have optimized thermal transfer from the LED array to the heatsink housing through a thermally conductive material. In one embodiment, to disperse and equalize the heat generated by LEDs 162, each LED can be positioned on the front side of circuit board 160 adjacent at least one via element (not visible) extending through circuit board 160 into connection with a via backing (not visible) on circuit board 160 formed of a thermally conductive material such as copper, beryllium oxide, aluminum, FR4, or graphene.
A secondary lens 170, similar to secondary lens 12 in first embodiment 10, is disposed over each LED 162. Lenses 170 preferably are formed in modular lens matrices (also referred to herein as lens subassemblies) 172 of lenses, e.g., a 4×4 array of 16 lenses (although other suitable lens matrices can be determined by the skilled artisan) arranged in a square matrix that can be screwed down on top of its respective LEDs, as shown in FIGS. 22-24.
To vary the size and shape of the field illuminated by each LED, the individual lenses 170 may be varied in capability, as shown in modular lens matrices (also referred to herein as lens subassemblies) 172a and 172b in FIGS. 27 and 30, respectively. A plurality of lenses comprising at least two different types of LED lenses can be used. Preferably, LED lenses standardized by the Illumination Engineers Society of America (IESA) are employed. For example, a module 172a, 172b may comprise a plurality of Type 5 (“round”) lenses 174, a plurality of Type 3 (“butterfly”) lenses 176, and a plurality of Type 2 (“skinny”) lenses 178. It will be apparent to the skilled artisan than many different combinations of lenses can be made. Thus because of this modular matrix lensing, a HILL assembly is provided wherein different IESA standard lens types can be provided within the same light fixture.
The lenses in the modular lens matrix can be rotated or adjusted to achieve different lighting configurations with the same HILL assembly.
In one embodiment, each HILL assembly module 142 is preferably about 12 inches long and the 64 LEDs 164 are powered to emit 64,000 lumens of light. Other suitable module lengths (in the range, for example, of 6-12 inches, 12-24 inches, 24-35 inches) will be readily apparent the skilled artisan. Modules can be used to create any desired configuration of modules, e.g., 1×2, 1×3 m 1×4 m 2×2, 3×3, 3×4, 4×4 etc.
A currently preferred embodiment, as shown in FIG. 21, provides a 24-inch heatsink housing comprising two HILL assembly modules 142. An advantage of this design is that modular lighting can be constructed in modular sections (e.g., 12 inch sections) that can be customized in many different configurations.
Referring now to FIGS. 24, 30a, 30b, 30c, 30c(1), and 31, driver circuitry 166 allows variation of the voltage across the LED strings to a minimal value required to maintain a constant current through all four strings. This ability to vary the output voltage to a minimal value decreases the power loss of those strings that require less voltage across the LEDs. This arrangement also allows the flexibility to change the number of LEDs per string as well as the number of LED strings (1 to 4) without the need to purchase a new constant current supply as in prior art arrangement. In the present invention, this function uses a single constant voltage power supply.
In typical prior art applications, a constant current supply is utilized without the use of circuitry to vary the output voltage, meaning that the constant current power supply's output voltage just climbs to whatever voltage the highest LED string needs. The other strings that require less voltage need to dissipate the excess power created by the high voltage setting which leads to inefficient and less reliable designs. In the prior art, if the number of LEDs were to change, a new version of constant current power supply would need to be selected.
In certain embodiments, the LEDs 162 can be dimmable by pulse width modulation (PWM). Thus, the HILL assembly can also comprise pulse width modulation (PWM) circuitry. The PWM circuitry converts the 0-10V analog signal to a PWM signal.
A method for maintaining a constant LED color temperature (CCT) and/or a color rendering index (CRI) in a lighting assembly (e.g., a HILL assembly) is also provided. The method comprises the steps of using constant drive current, thereby decreasing photon emissions; and varying pulse width modulation (PWM). These steps together provide overall dimming of the light output at frequencies higher than are currently on the market. Constant CCT and CRI are maintained while dimming from 100% to 0% because of this pulse width modulation (PWM).
With PWM come the benefits of maintaining a constant LED color temperature (CCT) and color rendering index (CRI). Preferably, PWM is conducted at higher frequencies in the range of 10 kHz to 20 kHz to comply with high definition cameras/filming. The higher frequency range also allows elimination of any audible noise in applications where necessary to do so.
In a specific embodiment, pulse width modulation (PWM) can be used at a frequency of 10 GHz to 24 GHz as a method to dim the light output. This frequency range allows the light output to be dimmed at an optimal frequency that is ideal for not interfering with other visible activities, including, but not limited to high definition television recording and broadcasting. Using PWM to dim the light output maintains the Color Rendering Index (CRI) and Color Temperature (CCT) of the LED.
In certain embodiments, the HILL comprises a 0-10V dimmer circuit. This allows the advantage of using a commercially available 0-10V dimmer switch, but such a switch does not provide a pulse width modulation (PWM) output.
In one embodiment, the HILL assembly is preferably IEC6929 annex compliant (on board) for 0-10V operation.
In a preferred embodiment, a HILL assembly comprises both a 0-10V dimmer circuit and a pulse width modulation (PWM) circuit. Positioning the circuitry adjacent to, or in association with the LEDs is particularly preferred. 2) there is constant voltage 3) pulse width modulation.
5.3. Methods for Making HILL Assemblies
The HILL assemblies disclosed herein can be made using conventional manufacturing techniques known in the art. The construction of the elements of the HILL assemblies will be readily apparent to the skilled practitioner. For example, heatsinks can be produced by conventional extrusion techniques. Power supplies and circuit boards are also made using conventional methods. No special manufacturing techniques or manufacturing environments are needed to produce the assemblies.
5.4. Index for Numbered Elements


    
    
        10 HILL assembly, first embodiment
        12 lens (or secondary lens) element
        14 CCLs
        16 LED module
        18 LEDs
        19 frosted lip
        20 first LED array
        22 heatsink housing
        23 groove surrounding the openings of cavity 56
        24 power supply
        25 concave lens surface of each CCL 14
        26 convex lens surface
        28 first O-ring
        30 first and second thermal gaskets
        32 interface plate
        34 second O-ring for sealing heatsink housing 22 at the front end
        36 third O-ring for sealing heatsink housing 22 at the rear end back plate
        38 back plate
        40 junction box
        42 sealing gaskets
        44 securing screws
        46 circuit board or card
        48 securing screws
        50 bores
        52 power supply connector
        54 screws
        56 open cavity
        60 mounting bracket
        62 fins of heatsink housing 22
        64 ambient light sensor
        66 occupancy sensor
        68 spot light
        70 arena/stadium light
        72 linear fixture for wider angle lighting
        110 HILL assembly, second embodiment
        122 linear, one-piece, finned, metal heatsink housing
        124 channels
        126 screws
        128 end plate
        129 opening in end plate
        130 T-slots
        132 mating T-features
        134 LED module
        136 opposed lips
        137 sealing lens
        138 outer beaded fins
        140 joiner 140
        142 HILL assembly module
        144 16-module assembly
        146 power supply casing
        148 bracket arm
        149 bracket cover
        150 power supply
        151 electrical access cover
        152 power supply wires
        154 openings to allow venting of heated air from the fins
        156 bottom panel
        160 circuit board
        162 LEDs
        166 driver circuitry for driving the LEDs
        168a, 168b first and second multi-prong connectors
        170 secondary lens
        172, 172a and 172b lens matrix
        174 round lenses
        176 butterfly lenses
        178 skinny lenses
        180 LED driver
    
    


The present invention is not to be limited in scope by the specific embodiments described herein. Indeed, various modifications of the invention in addition to those described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are intended to fall within the scope of the appended claims.
While embodiments of the present disclosure have been particularly shown and described with reference to certain examples and features, it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the present disclosure as defined by claims that can be supported by the written description and drawings. Further, where exemplary embodiments are described with reference to a certain number of elements it will be understood that the exemplary embodiments can be practiced utilizing either less than or more than the certain number of elements.
All references cited herein are incorporated herein by reference in their entirety and for all purposes to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety for all purposes.
The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention.

## Claims

1. A light emitting diode (LED) luminaire assembly, comprising:
a LED module comprising an array of a plurality of LEDs;
a circuit board;
a secondary lens structure comprising an array of lenses, wherein the lenses comprise concavo-convex lenses such that each lens creates wide dispersion optics, and wherein the lenses are positioned so that each LED is positioned entirely within a concave surface of a corresponding lens element lens;
a heatsink; and
driver circuitry for driving the LEDs in communication with the circuit board.

2. The LED luminaire assembly of claim 1, wherein:
the heatsink comprises a housing that includes a plurality of channels and a plurality of mating features for that mount and provide a thermal connection of the LED module to the housing; and
the assembly further comprises:
a sealing lens that protectively encloses the LED module within the housing, and
a mounting bracket capable of multi-angle positioning of the housing.

3. The LED luminaire assembly of claim 1, wherein:
the plurality of lenses in the secondary lens structure are formed in a plurality of modular lens matrices, and at least two of the matrices comprise different lenses.

4. The LED luminaire assembly of claim 1, wherein the LED assembly comprises one or more gaskets and is removable from the heatsink.

5. The LED luminaire assembly of claim 1, wherein the lenses of the secondary lens structure are integrated into a singular lens element and are comprised of plastic, acrylic, glass or polycarbonate.

6. The LED luminaire assembly of claim 1, wherein:
the LED array comprises a plurality of parallel strings of LEDs; and
the driver circuitry is configured to provide a constant current to the LED so that voltage delivered to each string of LEDs is automatically adjusted if any LED in the string fails.

7. The LED luminaire assembly of claim 1, wherein the driver circuitry further comprises pulse width modulation circuitry configured to enable dimming of the LEDs by varying pulse width modulation.

8. The LED luminaire assembly of claim 1, wherein the driver circuitry further comprises feedback circuitry for balancing power input to each of a plurality of LED strings.

9. The LED luminaire assembly of claim 1:
wherein a housing of the heatsink comprises a plurality of fins; and
the assembly further comprises an end cap that is secured to the heatsink and which includes at least one opening that is an intake for convectional cooling air into the heatsink which drives heat away from the fins of the heatsink housing.

10. The LED luminaire assembly of claim 1, further comprising a sensor for sensing or providing data relating to the LED luminaire assembly or to environmental parameters.

11. The LED luminaire assembly of claim 1, further comprising:
a power supply; and
a bracket body comprising at least one arm configured to support the assembly wherein the bracket body provides a cavity that holds the power supply.

12. The LED luminaire assembly of claim 1, wherein the secondary lens structure further comprises a hexagonal lens configured to create a uniform distribution of light from the plurality of LEDs.

13. The LED luminaire assembly of claim 2, wherein the sealing lens comprises a frosted lip for attenuating light emitted by the assembly.

14. A method of operating a LED luminaire assembly comprising a LED module comprising a plurality of LED strings each comprising a plurality of LEDs, a circuit board, a secondary lens structure comprising an array of lenses, a heatsink, and driver circuitry, the method comprising:
driving the plurality of LED strings at a constant current and varying pulse width modulation;
wherein the lenses elements of the secondary lens structure comprise concavo-convex lenses such that each lens creates wide dispersion optics, and wherein the lens elements are positioned so that each LED is positioned entirely within a concave surface of a corresponding lens.