HK1191390A - Compact and adjustable led lighting apparatus, and method and system for operating such long-term - Google Patents

Description

Compact and adjustable LED lighting device and method and system for long-term operation

Cross Reference to Related Applications

Priority of U.S. provisional application serial No. 61/446,915, filed 2011, 2, 25, § 119, which is hereby incorporated by reference in its entirety.

Technical Field

The present invention relates generally to Light Emitting Diodes (LEDs) and, more particularly, to the design of lighting devices and lighting systems that are used in a manner that maximizes the benefits of LEDs to meet difficult lighting needs.

Background

It is now well known that the use of LEDs in general lighting applications yields substantial benefits: most important are long working life, high efficacy and accurate light control. However, it is also well known that in order to make best use of LEDs, a number of factors must be considered: such as temperature (ambient and junction) and lighting (luminare) designs. LEDs are rapidly becoming the light source of choice for architectural or aesthetic lighting applications (e.g., facade lighting, holiday lighting, indoor runway lighting, etc.), but have been relatively slowly aware of their usefulness in long-term, large-scale lighting applications. This is due, at least in part, to the enormous effort required to control ambient and junction temperatures and the efficiency of the lamp design. Essentially, there is no standard large LED lighting fixture, since the benefits of operating LEDs are closely related to the specific lighting application. Only combining this with a basic understanding of the industry is it known how long an LED can operate effectively and it can be seen that there is great room for improvement in the art.

Consider an outdoor bridge spanning a length and accommodating a number of lanes in two directions; it is assumed that this bridge is heavily used both day and night. For the safety of night drivers, the roads on bridges must be illuminated, and there are applications that present challenges for modern lighting designers. Cost-effective proposals that the lighting fixtures should be secured to existing structural features (e.g., so as to avoid the cost of supporting a structure and the cost of closing multiple roadways to establish the structure); however, the mounting height and orientation of the fixtures must be considered so as not to cause glare or create other detrimental driving conditions (which is exacerbated by traffic flow in both directions). Lighting designers must take into account the placement of fixtures, the weight of fixtures, and the design of fixtures' appearance to ensure adequate light distribution on or near the target area and stress distribution on the pole (e.g., due to wind loading). At all times there are competing design considerations. For example, LEDs offer the benefit of long lifetime (which is cost-effective), but a large number of LEDs must be used to generate the required light (which compromises cost-effectiveness). Multiple light sources means that the composite light projected therefrom can be precisely controlled to suit the target area, but it also means additional optical elements for each light source (thereby increasing the cost and weight of each fixture).

Furthermore, there is a given interest in long-term use when starting to design lighting systems; in the above example, it is only economically infeasible to shut down multiple lanes for maintenance, light changes, etc. throughout the life of the system. Thus, LEDs are a natural choice, and their long life eliminates some concerns for long-term maintenance. However, since LEDs have such a long lifetime, they have not been adequately tested; thus, there is no clear answer on how long an LED can operate and how severely the light output can degrade over time due to thermal losses and light decay (not to mention the initial efficiency loss due to driver inefficiency and lamp design). The North American Society of Illumination Engineering (IESNA) recently recommended standards for testing LEDs (see IES LM-79) and measuring light decay (IES LM-80), but the scope is limited and does not define or provide an assessment of LED lifetime.

The art is in a deleted state; in the time that the LED is fully tested, the technology will be improved and the data is not particularly useful. At the same time, there are lighting applications that may benefit from the long life of the LEDs, provided that a long life can be guaranteed. What is needed is a means for reasonably ensuring long life of LEDs in a manner that is reliable and, unlike current maintenance strategies, cost effective for applications like the aforementioned bridges. Furthermore, what is needed is a means for reasonably ensuring an acceptable level of illumination over the lifetime, which is of little benefit to long-term maintenance of the LED lighting system if the light is allowed to fall to a useless pace. Still further, what is needed is a standardized method of developing large LED fixtures that can be used with the described means for ensuring long life of the LEDs to meet current demands, particularly fixtures suitable for outdoor use. Accordingly, there is room for improvement in the art.

Disclosure of Invention

For a number of reasons, Light Emitting Diodes (LEDs) are an attractive alternative to traditional light sources (e.g. metal halides, incandescent lamps, fluorescent lamps, high pressure sodium lamps) for many applications, especially for applications where long life is desired. So to speak, many large outdoor lighting applications are based on a budget and the budget is charged (assume) for a certain number of hours of operation before maintenance is performed or before the system has reached its end of life (EOL). This is problematic because the long life of an LED is highly dependent on operating conditions-many of which cannot be tightly controlled-thereby limiting the ability to predict or guarantee a certain number of operating hours. In addition, LEDs are not well characterized, so their performance has not long been well understood.

Accordingly, it is a primary object, feature, advantage or aspect of the present invention to improve upon the state of the art and/or to solve the problems, problems or disadvantages in the art.

According to the present invention, a lighting system is provided whereby the number of operating hours can be reasonably ensured for a particular combination of LEDs and fixtures. By means of the envisaged power compensation methodology and efficient lamp design, a relatively constant light level can be guaranteed for a defined lifetime of the system; this is true even if operating conditions change, known LED performance proves to be substandard in untested time, or some other occurrence that otherwise causes the EOL to advance and prevent the system from meeting the desired number of operating hours.

Further objects, features, advantages or aspects of the invention may include one or more of the following:

a. a customizable LED module for placement in a customizable LED fixture, making the fixture suitable for a variety of large-scale applications;

b. a method of aligning the module and the fixture to produce a customized composite beam pattern on, at or near a target area;

c. means for ensuring a relatively constant light output for a predetermined period of time;

d. means for providing an upward illumination in addition to or as part of the customized composite beam pattern;

e. a reliable lamp design suitable for outdoor use; and

f. means to adjust for undesirable operating conditions to help ensure long life of the LEDs in the LED fixture.

These and other objects, features, advantages or aspects of the present invention will become more apparent with reference to the attached description and claims.

Drawings

Reference will now be made in this description to the accompanying drawings, which are indicated by reference numerals and summarized below.

Fig. 1A shows an assembled perspective view of an LED module according to aspects of the present invention.

FIG. 1B shows the module of FIG. 1A in an exploded perspective view.

FIG. 1C shows the module of FIGS. 1A and B taken along section line A-A of FIG. 1A.

Fig. 2 shows an enlarged, isolated front view of the LED board of fig. 1A-C.

Fig. 3A-E show various individual views of the housing of fig. 1A-C.

Fig. 4A-C show various enlarged individual views of the lens of fig. 1A-C.

Figures 5A-D illustrate various separate views of the visor (visor) of figures 1A-C.

Fig. 5E-I show isolated perspective views of some possible shields for use with the LED modules of fig. 1A-C.

Fig. 6A shows an isolated assembled perspective view of one possible design of a pivot joint for use in the LED module of fig. 1A-C in accordance with aspects of the present invention.

Fig. 6B shows the pivot joint of fig. 6A in an exploded perspective view.

Fig. 6C and D show various views of the pivot joint of fig. 6A and B as it operates.

Fig. 6E shows an assembled side view of an alternative pivot joint for use in the LED module of fig. 1A-C.

Fig. 6F and G show various views of yet another alternative pivot joint for use in the LED module of fig. 1A-C.

Fig. 6H shows an assembled perspective view of yet another alternative pivot joint for use in the LED module of fig. 1A-C.

Fig. 7 illustrates two possible methods of aligning a module bar within a fixture housing according to aspects of the present invention.

Fig. 8A-G show a number of separate views of a module bar according to aspects of the present invention.

Fig. 9 shows an enlarged isolated perspective view of the module bar of fig. 8A-G with a plurality of modules of fig. 1A-C installed.

Fig. 10A-C show a number of separate views of a fixture housing (oriented 30 ° downward from horizontal) according to aspects of the present invention.

FIG. 10D shows an enlarged view of the fixture housing of FIGS. 10A-C along section line A-A and including one module bar (see FIG. 8) and one LED module (see FIG. 1-C) mounted in accordance with aspects of the present invention.

Fig. 11A schematically illustrates a prior art method of illuminating a road.

FIG. 11B schematically illustrates one possible method of illuminating a roadway, in accordance with aspects of the present invention.

FIG. 12 illustrates, in flow diagram form, a method of designing a composite beam pattern in accordance with aspects of the present invention.

FIG. 13 illustrates, in flow chart form, a method of orienting an exemplary fixture to achieve a composite beam pattern designed in accordance with the flow chart of FIG. 12.

Fig. 14A shows an assembled perspective view of an LED fixture according to aspects of the present invention.

Fig. 14B shows an exploded perspective view of the external elements of the LED fixture of fig. 14A.

Fig. 14C shows an enlarged view of detail a of fig. 14A.

FIG. 14D shows the LED fixture of FIG. 14C along section line B-B, with some shading omitted for clarity.

Fig. 15A illustrates portions of an exemplary lighting system according to aspects of the present invention.

Fig. 15B shows an enlarged isolated perspective view of the example fixation device and the example hinge (knuckle) of fig. 15A.

FIGS. 15C and D show perspective views of the rod of 15A alone, and views along line A-A

FIG. 15E illustrates an enlarged, isolated, assembled perspective view of the exemplary hinge of FIG. 15B.

Fig. 15F shows a partially exploded view of the exemplary hinge of fig. 15E.

Fig. 16 illustrates, in flow chart form, a method of operating the exemplary lighting system of fig. 15A-F in accordance with aspects of the present invention.

FIG. 17 schematically illustrates a method of providing both upward lighting and directional (i.e., task) lighting applications, in accordance with aspects of the present invention.

Fig. 18A shows an alternative to the modular strip of fig. 8.

Fig. 18B shows an alternative to the module bar and LED module of fig. 9.

Detailed Description

For a further understanding of the invention, specific exemplary embodiments according to the invention will be described in detail. In this description reference will often be made to the accompanying drawings. Reference numerals will be used to refer to certain parts of the drawings. Like reference numerals will be used to refer to like parts throughout the drawings.

Devices, methods, and systems are contemplated for reasonably ensuring that large outdoor LED lighting systems operate at relatively constant light levels over a prescribed period of time. LEDs offer many benefits including long operating life, RoHS and LEED compliance, no re-shutdown, good color stability (even across dimming levels), and high efficacy, to name a few. That being said, it should be understood that aspects of the present invention may be applicable to other lighting applications, other types of light sources, and the like. Further, while various alternatives and alternatives are set forth, they should not be considered limiting or all-inclusive.

It is believed that a full understanding of the present invention is best achieved by first understanding the components that form the contemplated long-term LED lighting system together with the contemplated methodology; the remaining description is so stated, unless otherwise indicated, but is not intended to indicate a specific sequence of components or events.

With respect to terminology, it is to be understood that the terms "light fixture" and "fixture" are used interchangeably in this specification and are intended to encompass the sum of the modules and associated external components. The grouped luminaires or fixtures (usually on the same elevated structure) are referred to as an array, while the term "lighting system" refers to the sum of the luminaires or fixtures, the elevated structure, the means for attaching the luminaires or fixtures to the elevated structure, the power conditioning components, the control components, etc. The term "warranty" is used throughout the specification and is intended to mean warranty or proximity to warranty conditions, events, or the like, except in the event of extreme operating conditions (e.g., driving an LED well beyond its rated capacity), extreme environmental conditions (e.g., snow storms), natural disasters (e.g., earthquakes), or the like. The term "relatively constant light" is used throughout the specification and is intended to mean that the light perceived by the average human eye is constant, whether or not the light is constant from a lumen output perspective. Finally, the terms "beam output pattern", "beam pattern", "output pattern", "light pattern", "beam output", and "light output pattern" are used interchangeably in this specification and are intended to define the shape, size, and/or nature of light emitted from a source. In some cases, the source may comprise a single LED, and in other cases, the source may comprise a single fixture housing a plurality of LEDs and associated means to shape the light projected therefrom; when juxtaposed, the beams are generally referred to as "single" and "compound" respectively.

A.LED Module

The heart of the contemplated LED lighting system is a number of LED modules. As can be seen in fig. 1A-C, the module 10 includes a circuit board 200 disposed at one end of a housing 300, the housing 300 being secured to the pivot joint halves 101 (e.g., by screws as shown or otherwise) to enclose the circuit board 200. LED module 10 also includes lens 400 disposed in generally opposite ends of housing 300, lens 400 further being positionally fixed by visor 500, visor 500 being securable to housing 300 by screws (as shown) or otherwise.

Fig. 2 shows the circuit board 200 in more detail. As shown, each LED module 10 includes a single board 200 on which a single LED201 is mounted; in this example, model XP-G or XM-L is commercially available from Cree, Durham, NC, USA (although other types, models and brands of light sources are possible) and is contemplated. Circuit board 200 also includes a push button junction box 202 (also known as a poke-in connector) to facilitate quick replacement of the LEDs if they fail; in this example, model 1-1954097-1 is commercially available from Tyco Electronics, Berwyn, PA, USA (although other models and types of connectors are possible) and is contemplated. Board 200 also includes cutouts 203 and holes 204 to ensure that circuit board 200 is properly oriented within module 10, although this is not a limitation of the invention. If desired, the board 200 may have a plurality of LEDs mounted thereon and connected in series; this will directly affect the efficacy of a given power input, as well as the beam output pattern projected therefrom, and is discussed in provisional U.S. application serial No.61/539,166, which is incorporated herein by reference.

Fig. 3A-E show various views of the housing 300. The rear surface 302 of the housing 300 is adapted to receive the circuit board 200 and secure the board 200 in place by bolts (or similar means) passing through holes 301, arcuate apertures 203 (see fig. 2) and into threaded blind holes (see fig. 6A) in the pivot half 101; as an alternative, a nut and bolt combination (or similar device) along with a through hole may be used in place of the threaded blind hole in half 101. Front surface 306 of housing 300 is adapted to receive lens 400 through aperture 303 and allow limited rotation thereof through track 304, as well as to receive visor 500 by a thread cutting screw through aperture 501 (see fig. 5A) and into aperture 305. The housing 300 also includes a void (void) 308 that is a wireway for wiring associated with the LED201 and a post 307 that extends through the aperture 204 of the board 200 to ensure proper orientation of the board 200.

As envisaged, the housing 300 is designed as an anchor point for the LED module 10. For example, if an LED fails, the bolt can be removed from the hole 301, the wire cut, the defective board removed, a new board 200 placed against the surface 302, the wire reconnected by the poke connector 202, and the bolt passing through the hole 301 secured again; this can occur quickly without interfering with the precise alignment of the pivot joint 100 or the orientation of the lens 400. Alternatively, if a lens needs to be replaced (e.g., to achieve a different beam output pattern), visor 500 can be removed by removing a thread cutting screw from the now threaded hole 305, removing the old lens, placing a new lens 400 in aperture 303 of surface 306, and re-securing the visor by a thread cutting screw through aperture 501 and into threaded hole 305; this can occur quickly without interfering with the alignment of the LED201 or pivot joint 100.

Fig. 4A-C show various views of lens 400. With respect to the drawing figures, which show a typical narrow beam lens-lens 400 includes a generally parabolic outer surface 401, a face 402 adjacent to the LED, and a light emitting face 403. Light emitted from the LED201 enters the face 402, is collimated, and projects outward from the light emitting face 403 by Total Internal Reflection (TIR), as is well known in the art. Lens 400 also includes tabs 404 to facilitate (i) ensuring proper placement between visor 500 (see reference numeral 506 in fig. 5B) and housing 300 (see reference numeral 304) and (ii) allowing easy rotation of lens 400 (e.g., for in-situ adjustment).

The exact design of the lens 400 may vary depending on the application, for example, the orientation of a particular module 10, the number and arrangement of LEDs 201 on the board 200, and the desired beam output. In practice, each LED module 10 may have a different lens 400, which may require multiple sizes and shapes of apertures 303 in housing 300 and apertures 505 in visor 500. For the circuit board shown in fig. 2, the lenses shown in fig. 4A-C may be most suitable as one example. The shape of lens 400 (but not its function) and the shape of apertures 303 and 505 may be expected to vary if multiple LEDs 201 are mounted to circuit board 200, as in the above-mentioned U.S. provisional application serial No.61/539,166. This is best illustrated by comparing the lens of fig. 4A-C of the present application (sized for a single LED) with the lens of fig. 2 of U.S. provisional application serial No.61/539,166 (sized for two LEDs in a linear or "oval" array) and the lens of fig. 6 (sized for four LEDs in a 2X2 or "square" array). As another example, any number of commercially available lenses may be used. For example, any FCP series lens available from Fraen Corporation, Reading, MA, USA may be used with a light shaping diffuser (e.g., any light shaping diffuser available from luminet, Torrance, CA, USA) to approximate the desired beam output pattern; however, in this example, the visor 500 would likely need to be modified to positionally fix the diffuser.

Figures 5A-D illustrate various views of visor 500. As envisioned, visor 500 includes a central aperture 505, light emitted from lens 400 passing through central aperture 505; the light is redirected off of the reflective surface 507 and toward the target area. Visor 500 also includes short and long sides (referenced 504 and 503, respectively) to provide a unique cut off for light projected to either side of module 10 (e.g., to prevent shadowing that may occur when light from one module hits another module). To further ensure that the light is precisely controlled, edges 503 and 504 and top 508 have darkened ribs 502; ideally, all surfaces of visor 500 except reflective surface 507 are blackened (e.g., formed of black polycarbonate). As is well known in the art, poorly controlled light can not only limit the effectiveness of illuminating a target area in a desired manner, but can also cause glare. While blackening visor 500 (except for surface 507) is sufficient glare control for some applications, it has been found that even blackened surfaces have somewhat high reflectivity at high angles of incidence. The ribs 502 effectively capture and absorb any remaining light that may cause glare (also known as internal glow).

In practice, visor 500 may be molded or otherwise formed from black polycarbonate and then surface 507 is metalized (e.g., aluminum polishing may be used in a polisher MT-11000 available from Mold-Tech, Windsor, Ontario, Canada). Alternatively, visor 500 may be formed of a high reflectivity material (e.g., polished aluminum) and all surfaces except 507 are blackened, or visor 500 may be formed of a low cost polymer, blackened, and strips of high reflectivity material inserted into visor 500 to create surface 507. All components of the module 10 except the reflective surface 507, the lens 400, and the LEDs 201 may be blackened, if feasible. The surface 507 itself may be coated, peened, or otherwise formed to provide specular, diffuse, or any other property of reflection as desired for the application.

As with lens 400, the exact design of visor 500 can vary depending on the application, the desired beam output, and the orientation of module 10. For example, the visor may have two long sides (see reference numeral 503) or two short sides (see reference numeral 504). Visor 500 may be longer or shorter than that shown (the visor shown in fig. 5A is approximately 3 inches long) or may be rounded and without ribs. Some possible visor designs are shown in fig. 5E-I.

Fig. 6A-D illustrate one possible design of a pivot joint for use in module 10. In general, the pivot joint 100A includes a portion 101 adjacent to the LED, a portion 102 adjacent to the fixture, and a stabilizing portion 103. In practice, pivot joint 100A is assembled and secured to modular bar 50 by bolts 107, washers 104 and 105, and nuts 106 (see also fig. 8A-G). By loosening the bolt 107, the LED module 10 can pivot about a first axis (see axis B in fig. 6C) extending along the length of the circular portion 115 of the portion 101, and can pivot about a second axis (see axis a in fig. 6C) extending along the length of the bolt 107; as envisaged, pivoting about axis B determines the vertical orientation angle, while pivoting about axis a determines the horizontal orientation angle (see table 1), but this may be different. The configuration of the bolt 107, washers 104 and 105, and nut 106 ensures that only one hand is required to tighten or loosen the assembly, thereby releasing the other hand to adjust the module 10; this is useful if the module 10 must be reoriented in the field. Another important feature of pivot joint 100A is bolt 107; it can be seen that the side of bolt 107 is machined flat. This may ensure that once bolt 107 is inserted into slot 51 of module 50 (see fig. 6C and 8D, G) and module 10 is moved to its correct position and oriented, tightening pivot joint 100A will not accidentally rotate bolt 107 and alter the precise alignment of module 10; similarly, the webs 114 on the portion 101 adjacent the LED prevent lateral movement of the pivot joint 100A during tightening, which could also inadvertently affect the precise alignment of the module 10. Yet another important feature of the pivot joint 100A is the design of the portion 101 adjacent to the LED; the rounded back portion 115 of portion 101 ensures that module 10 can be mounted right side up or upside down (as will be discussed later), and the flat surface of portion 101 ensures a universal mounting surface for any number or type of light sources (e.g., portion 101 can receive a socket for a more traditional type of light source). Finally, as envisaged, the joint is formed from aluminium or some other heat conducting material; this provides the benefit of a heat sink for the LEDs 201 in the module 10.

Of course, other designs of the pivot joint are possible and may be envisaged. For example, fig. 6E shows a pivot joint that may be more suitable when modular strip 50 includes protrusion 53. The alternative pivot joint 100B also includes a portion 102 adjacent the fixture and a portion 101 adjacent the LED; however, pivoting of the module 10 is now achieved by adjusting the two bolts 107A and 107B (as opposed to the bolt 107 of fig. 6B). Yet another alternative pivot joint l00C is shown in fig. 6F and G. In this alternative, pivoting of module 10 is also accomplished by bolts 107A and 107B (similar to pivot joint 100B), but the joint itself is a larger substantial heat sink; this may be beneficial if a multi-chip LED or multiple LEDs are used in each module 10. Yet another alternative pivot joint 100D is shown in fig. 6H. In this alternative, the module 10 (when mounted on the pivot joint half 101) may be moved along the channel 55 of the alternative module bar 50 until the desired position is reached. Pivot half 101 may then pivot about a first axis (extending radially through portion 102) while being at least partially contained within a slot in portion 102, and/or portion 102 may rotate within channel 55 about a second axis (extending longitudinally through portion 102) until a desired orientation is achieved. The stabilizing portion 103 may then be secured (e.g., by screws 107 in the apertures 54) to positionally fix the module 10 in the desired orientation. Pivot joint 100D may be preferable if the module is tightly packed in the fixture housing-because it is not necessary to reach around, under, or behind the pivot joint to secure the module when orienting/reorienting-or if the module must be installed or oriented in place rather than then being installed on a module strip in the fixture housing.

Regardless of the precise design of pivot joint 100, it would be beneficial if the joint (i) established a heat dissipation path between module 10 and the fixture housing, (ii) allowed a wide range of orientation angles for module 10, (iii) allowed quick and easy assembly, and (iv) was compact in design to allow more efficient mounting of module 10 in the fixture.

B.LED fixing device

As envisaged, a certain number of LED modules 10 are oriented and mounted in a fixture, which is also oriented and mounted (typically on a bar or other elevated structure); the exact number of modules and the directional position of each module may vary depending on the application, the size of the fixture, the composite beam output pattern, etc. The mechanics of the mounting of the modules in the fixture housing is discussed first, followed by a description of one possible way of designing the composite beam output to suit the application and one possible way of orienting the fixture and the modules therein to achieve the composite beam output.

Each LED fixture is designed to contain one or more module bars 50 (see fig. 8A-G), with one or more LED modules 10 secured to each module bar 50 (see fig. 9). As envisaged and shown in fig. 7, the module bar may be mounted into the reflector housing parallel to the ground (a) or parallel to the orientation axis (B) of the reflector housing to ensure efficient packaging of the LED module 10-although the module bar may be mounted in the reflector housing in any manner. In general, a large outdoor lighting fixture 1000 includes some form of elevated structure 80, some form of housing 70, and a number of modular bars contained therein (regardless of their orientation).

An exemplary design of module bar 50 is shown in fig. 8A-G. It can be seen that the module bar 50 is curved to match the interior of the exemplary design of the reflector housing 60 (see fig. 10A-D) and includes a hole 52 and an aperture 51. As previously mentioned, in practice, the modules 10 may be secured to the module bar 50 by a bolt and nut combination (or similar means) passing through the pivot joint 100A and the aperture 51; the module can then be moved along the length of the aperture 51 until the desired position is reached. The module bar 50 may be secured to the reflector housing 60 by bolts (or similar means) passing through the holes 52 and into complementary threaded blind holes in the housing 60. Of course, the modules 10 may be secured directly to the housing 60, but this would require orienting each LED module 10 in place, which can be time consuming and difficult if the housing 60 had been designed to contain a large number of efficiently mounted modules.

An exemplary design of reflector housing 60 is shown in FIGS. 10A-D; as shown, the housing 60 is oriented 30 ° downward from horizontal (i.e., a vertical orientation angle of 30 °), but this is by way of example and not by way of limitation. The housing 60 includes wire slots 61 that allow wiring from each board 200 to exit each module housing 300 (through the cavity 308) and exit the fixture housing 60 to the remotely located electronics enclosure 110 (see 110A and 110B in fig. 15A); ideally, the wiring is never exposed to the components, so that the envisaged fixture is reliable and suitable for outdoor use. The housing 60 also includes a threaded blind hole 62 (or similar feature) for securing the housing 60 to a rod or other elevated structure 80; in this example, by an adjustable stand similar to that described in U.S. patent application serial No.12/910,443 (see fig. 15A-F), which is incorporated herein by reference.

As noted, the exact design of each LED fixture may vary depending on a number of factors. However, regardless of the design of the fixture, the nature of the application, or other such factors, an exemplary method of establishing the fixture to suit the application requirements is the same, and such a method is illustrated in FIG. 12. The exemplary method 2000 will now be discussed in the context of a large outdoor lighting system (particularly a bridge lighting system); however, it will be appreciated that the method 2000 may be applied to other applications, and the following is merely one way of practicing various aspects of the present invention.

The exemplary method 2000 begins by determining the requirements of the lighting application (see reference numeral 2001). For bridge lighting applications, some possible requirements may include, but are not limited to, the following.

1. Size and shape of target area

a. While the road across the bridge is most important, the target area may also include areas adjacent to the road (e.g., sidewalks) and/or defined spaces above the road (e.g., illuminated structural features for aesthetic purposes).

2. Level of illumination

a. The target area may have a specified minimum illuminance (e.g., measured in horizontal and/or vertical footcandles), a specified uniformity of illumination (e.g., a ratio of maximum illuminance to minimum illuminance, a ratio of average brightness to minimum brightness), and so forth.

b. The Philips Lighting company Lighting Handbook (Philips Lighting company Lighting Handbook), which is incorporated herein by reference, explains in detail the nature of light and how it is characterized and measured; it is assumed that a person of ordinary skill in the art is familiar with these concepts and therefore the basic light measurement principle is not discussed herein.

3. Special requirements

a. As mentioned before, a particularly challenging bridge lighting application is one in which the road comprises a plurality of lanes, wherein at least some of the plurality of lanes extend in opposite directions. Thus, the designer must consider not only the lighting requirements for road lighting, but also glare and other lighting conditions experienced by the driver.

b. Chapter 13 of the above-mentioned philips lighting company lighting handbook, which is incorporated herein by reference, discusses many details of road lighting.

c. U.S. patent application serial No.12/887,595, incorporated herein by reference, discusses unique lighting application requirements with opposing lanes and apparatus and methods for addressing these requirements.

Knowing the requirements of the lighting application, the limiting factor can be determined (see reference numeral 2002). With respect to many of the steps in methods 2000 and 3000 (see FIG. 13), there are few definitive answers to step 2002; rather, more desired answers depend on the designer's abilities, the nature of the application, budget, etc. Given (for illustrative purposes only) that the application requires the lighting fixture to be secured to existing structural features and for aesthetic purposes, the customer has selected a particular size and style of fixture housing. Obviously, any preference of the designer, customer or administrative subject (e.g., IESNA) will impose some limitations on the project, but in this example, the primary limiting factors are the mounting height of the fixtures (since the elevated structure is limited by the pre-existing structural features), the weight of the lighting system (so the load capacity of the pre-existing structural features is not exceeded), and the number of fixtures (since the size of the fixture housing is defined, the space for mounting the fixtures is limited, and the overall weight of the lighting system is limited).

Knowing the requirements of the application, the designer can design the composite beam (see reference numeral 2003). To show aspects of the invention according to steps 2003 and 2004, a comparison with prior art lighting is necessary. Conventional roadway luminaires are suspended above the roadway (e.g., by L-shaped poles) and project light downward; because the light is projected downward, the light fixture must be mounted above a certain height so the typical driver cannot directly observe the light source (i.e., subject to glare). However, because the present application has lanes extending in opposite directions and requires the use of existing structural features, conventional roadway luminaires are not suitable for the application. It will be appreciated that if conventional roadway fixtures were used, multiple rods may protrude above roadway 20 in multiple directions from the top of existing support 80 to provide sufficient lighting, and thus would not be cost effective or structurally unreasonable according to the limitations of step 2002. Accordingly, for purposes of illustrating various aspects of the present invention, it is appropriate to make a comparison to a sports lighting type fixture.

Fig. 11A shows a target area 20 (in this example, a road on a bridge) as it might appear to be illuminated by a conventional sports lighting fixture array 900. As can be seen in fig. 11A, each array 900 is suspended from an existing structural feature on a bridge, and each array illuminates one direction of traffic flow (presumably meeting all of the major limiting factors of step 2002). As is well known in the art, conventional sports lighting fixtures are designed as a single high power light source (e.g., a 1000 watt metal halide lamp), which is necessary so that the entire width of the roadway in each direction can be adequately illuminated. Fig. 11A illustrates two problems with using conventional sports lights in a relatively compact space at a shortened installation height (e.g., tens of feet shorter than conventional sports lighting applications). Since the conventional luminaire 900 uses a single high power light source, a region 2 of high intensity (also referred to as a "hot spot") occurs directly below the support structure 80 and the region of leakage light 1 illuminates the area outside the roadway 20; both of these effects are undesirable and waste light. These deficiencies are addressed, at least in part, by the large outdoor lighting fixture 1000 utilizing aspects of the present invention, because light emitted from multiple precisely controlled light sources can be used to create a composite beam of light that meets the needs of a lighting application without wasting light (see fig. 11B). Looking back at step 2003 of method 2000, the composite beam in FIG. 11B may be developed in accordance with, but is not limited to, the following.

1. The initial composite beam pattern may be developed from step 2001 taking into account the desired light level, uniformity, and/or other characteristics.

2. From step 2002, the mounting location and number of fixtures can be determined and potential hot spots identified, taking into account the limiting factors.

3. With the information from steps 1 and 2 and knowing the principle of inverse square Law (inverses Law), the composite beam can be broken down into a narrow beam projected furthest from the determined mounting location and a wide beam projected closest to the determined mounting location.

a. It is assumed that one of ordinary skill in the art of lighting design is familiar with the inverse square law, and therefore such mathematical equations/relationships are not discussed herein.

b. The terms "narrow beam" and "wide beam" are commonly used to describe the shape/size of the beam pattern and are widely used in the art.

c. Each individual beam pattern making up the composite beam pattern may need to be superimposed with adjacent beam patterns to ensure that uniformity, specified illumination levels, or other considerations of each step 2001 are met. An exemplary approach is to overlap each beam pattern at 80% of its beam angle, where the beam angle defines the shape/size of the beam pattern at 50% of the maximum luminous intensity.

Once a suitable composite beam pattern has been developed and includes a number of suitable individual beam patterns, each individual beam pattern may be assigned to the fixture according to step 2004 of method 2000 (see step 2 above). Likewise, there is no correct determination for step 2004; rather, the preferred decision depends on a number of factors. As an example, at the height of the fixtures, it may be beneficial for aesthetic reasons to assign the same number of individual beam patterns to each fixture (e.g., to ensure that each fixture contains the same number of modules), or to assign individual beam patterns according to a particular layout (e.g., to ensure that each fixture is oriented at the same angle regardless of the orientation angle of the modules installed within each fixture). As an example, at the module height, two separate beam patterns may be assigned to two modules, each of which contains a single LED therein, or two separate beam patterns may be assigned to a single module, which contains a plurality of LEDs therein.

Finally, the complexity of step 2004 will be determined by the degree to which the fixture can be customized. Customization can be adjusted by, for example, selecting the orientation angle (of the fixtures, modules, and module bars, if desired), the light propagation elements (e.g., the size and design of lens 400), the light blocking elements (e.g., the size and design of visor 500), and the light redirecting elements (e.g., the size and design of reflective surface 507). It is noted, however, that step 2004 may be completed before step 2003 (i.e., the details of the fixture are first determined, after which the resulting composite beam is built and inspected according to steps 2001 and 2002), depending on the limiting factors determined in step 2002.

Once each individual beam pattern has been assigned to a fixture according to preference, restriction, or otherwise, each fixture may be appropriately constructed and oriented according to method 3000 in fig. 13. The first step is to determine the requirements of the fixture (see reference numeral 3001); as previously mentioned, the entire LED lighting system is highly customizable, so it is likely that each fixture in the system has unique requirements. For the above-described bridge lighting applications, some possible fixture requirements may include, but are not limited to, the following.

1. Orientation angle of fixture housing 60

2. Color and finish of the fastening device

3. Special installation considerations

4. Number, placement and orientation of module bars 50 within housing 60

a. The exact number of module bars 50 is directly related to the number of modules 10 that the housing 60 must contain, which is directly related to how many individual beam patterns are associated with a particular fixture. If desired, the composite beam may be subdivided into a number of individual beam patterns, such that each module 10 is associated with an individual beam pattern, although it is somewhat impractical to assume that the output pattern emitted from a single module 10 is relatively small-particularly with respect to the target area 20.

5. Positioning and orientation of module 10 within housing 60

a. The precise orientation of each module will depend, for example, on the mounting height of the fixture housing 60, the orientation angle of the housing 60, the orientation of the module bar 50 relative to the orientation angle of the housing 60, and the location of the individual beam patterns relative to the housing 60.

Once the requirements of the fixture have been determined according to step 3001 of method 3000, the fixture housing itself may be oriented according to step 3002 (see also fig. 10A); again, some methods of orienting the fixture housing to meet roadway lighting having multiple opposing lanes therein are discussed in the above-mentioned U.S. patent application Ser. No.12/887,595.

Once the fixture housing 60 is oriented according to step 3002 of method 3000, a first module bar/LED module assembly (see also fig. 9) may be constructed according to step 3003. Each assigned module 10 will have a particular combination of optical elements (e.g., the size and shape of visor 500 and the type of lens 400) and be assigned a particular location on module bar 50; this is in contrast to the practice of assembling custom reflectors discussed in U.S. patent No.7874055, which is incorporated herein by reference.

Once the LED modules 10 are mounted on the module bar 50, each LED module may be oriented according to step 3004 of method 3000. As previously mentioned, it may be impractical to assign a separate beam pattern to each LED module; more likely, the composite beam will be broken down into enough individual beams with one or more rows of LED modules (see fig. 9) associated with the individual beam patterns (although this may be different). Knowing the orientation angle and position of the fixture housing 60 relative to the composite beam pattern (i.e., relative to the target area), knowing the orientation and position of the module bar 50 within the housing 60, knowing the position of the individual beams within the composite beam, and knowing which modules 10 are assigned to which individual beams, the precise orientation of each module 10 mounted on the pole 50 can be determined; table 1 shows an example. It can be seen that each module is associated with a particular module bar, having a particular position thereon, having a particular vertical orientation angle and horizontal orientation angle, having a particular number and type of LEDs, and having a particular lens type (e.g., "oval V" means an oval lens having an elongated axis in the vertical direction-see, e.g., the above-mentioned provisional U.S. application serial No.61/539,166, as one example of an oval lens suitable for use with multiple LEDs mounted on a single circuit board). It is noted that additional options for each module, such as specific size, shape, and cutoff angle (cutoff angle) of the visor, have been omitted for the sake of brevity, and table 1 is merely to illustrate some of the factors associated with establishing the contemplated LED fixture.

TABLE 1

As can be seen from the examples in table 1, each module 10 may need to pivot about one or two axes as shown in fig. 6C. In addition, the module may require rotation of its visor and/or lens to produce the desired effect. As previously described, tabs 404 of lens 400 seat in grooves 506 of visor 500, which allows a person to pivot visor and lens together a specified amount along track 304 of housing 300; in this example, the arc defined by the aperture 501 is about 60 ° (a complete rotation of which may require removal of one or more bolts from the hole 305), but the lens itself may be rotated 90 ° (which is very useful for orienting an elliptical lens) by seating in a separate groove 506.

The mechanics of orienting the modules 10 have been discussed, but in order to do so in a quick and repeatable manner, it would be beneficial if all of the modules associated with the individual beam patterns were aligned with a common datum-easily visible to the assembler-while being secured to the module bar 50 (but before the module bar 50 is mounted in the fixture housing 60). U.S. patent application serial No.12/534,335, incorporated herein by reference, discusses methods of orienting multiple objects to a common reference, but other methods are possible and contemplated. In practice, each individual module may have a laser mounted thereon, and the module pivots until the beam projected from the mounted laser matches the position of the target point projected onto the wall or floor. This same method can be applied to a module bar because the lasers can be mounted to the bar and oriented to a reference point, and once the bar is oriented, each LED module mounted to the module bar is considered accurate. The orientation of the fixture housing can also be ensured in the same way. Of course, no laser need be used; a sensor/receiver arrangement may be used. There are a number of ways in which the LED module 10 may be accurately oriented and, although it may be the easiest way to orient the LED prior to installation in the fixture housing 60, it does not depart from the various aspects of the invention that orient the module in place.

Once the module bar/LED module assembly is fully erected and oriented, it may be installed in the fixture housing 60 according to step 3005 of method 3000. Ideally, once secured to the interior of the housing 60, no additional orientation or modification of the assembly is required. The process is repeated according to step 3006 for all modules in a given fixture, after which the external components (see fig. 14B) are secured according to step 3007 to form exemplary fixture 5000. Step 3007 is generally performed according to the following (see FIGS. 14A-D), but is not limited to such.

1. The gasket 45 is placed in a complementary recess in the opening of the housing 60.

a. The gasket 45 is necessary to ensure that the fixture 5000 is suitable for outdoor use and to ensure the integrity of the module 10 without separate sealing.

b. The unique design of the fixture housing 60 and lens frame 40 (see fig. 14D) protects the gasket 45 from direct sunlight (e.g., if used outdoors) and light emitted from light sources (e.g., LEDs 210), which could otherwise prematurely degrade the gasket 45.

c. If desired, the fixture 5000 may also include a ventilator (e.g., any type of protective ventilator available from w.l. gore & Associates, inc., Newark, D) to help maintain the proper internal pressure within the fixture 5000 (e.g., in the event of environmental changes).

Such ventilators are well known in the art.

2. The outer lens 30 is positioned over the opening of the housing 60.

a. As contemplated, the outer lens 30 includes an anti-reflective coating-as is commonly used in the optical element art-to reduce internal reflection from 8% to about 2%.

3. The lens frame 40 is positioned on the lens 30.

4. The screws 41 are screwed into the housing 60 through the tabs 43 of the lens frame 40 to compress the outer lens 30 between the lens frame 40 and the housing 60.

5. The outer shield 90 is positioned in a complementary recess of the lens frame 40.

a. In the bridge lighting application in question, each fixture 5000 is aimed at the flow of traffic and each module 10 contained therein is precisely oriented so that the outer shield 90 is not designed to provide a distinct partition (as designed, the shield 90 is angled downward by about 20 °, although this may vary); rather, visor 90 is designed to reduce internal glow (i.e., reduce perceived light source brightness) and reduce the effects of wind loading on fixture 5000. However, for purely aesthetic reasons, the outer shield 90 may be designed to provide a unique break, or otherwise designed.

6. Screws 42 are threaded into tabs 44 of lens frame 40 to secure outer shield 90.

C.LED lighting system

Fig. 15A-F show portions of an exemplary LED lighting system designed to meet the bridge lighting application as previously described. According to aspects of the invention, a plurality of exemplary fixtures 5000 (only one shown for clarity) are secured to exemplary poles 81 (see FIG. 15C) by brackets (see FIG. 15B, E-F) and aligned with the traffic flow to produce an exemplary composite light beam output pattern 21 (only a portion of which is shown for clarity) at target area 20. As envisioned, each fixture 5000 requires one or more drivers 111 to provide power to the plurality of LEDs 201; in this example, each fixture requires three drivers each rated at 150 watts to operate about 80 XP-G Cree LEDs (e.g., model TRC-150S 140DT available from Thomas Research Products, Huntley, Illinois, USA) with each LED between 0.7 and 1.4 amps, although this may vary depending on the application. The housing 110B houses the drive 111 for the fixture 5000, while a similar housing 110A houses the controller 112 and the equipment 113 necessary for complying with safety requirements; in this example, the device 113 includes a main disconnect switch, a junction box, a fuse box, and a surge suppressor, but this may vary depending on the application. If desired, the housings 110A and 110B may be mounted inside the pole 80 or under the roadway 20, for example, for aesthetic purposes, or otherwise mounted.

The exact contents of the housings 110A and 110B will vary depending on the application requirements. For example, it may be beneficial for the controller 112 to be able to dim the lights and turn them on and off in response to some command. The command may be convenient in the field (e.g., by the main switch opening described above) or received from a remote location (e.g., from a control center as described in U.S. patent No.7778635, incorporated by reference herein). If the latter is desired, devices networking multiple fixtures 5000 on multiple poles must be considered. The wired network may utilize power line communication to connect each pole and place the entire system in communication with a remote control center. In addition, if a wireless network is desired (e.g., based on a ZigBee platform), the controller 112 may include functionality to perform the corresponding operations; examples of wireless control of LED lighting systems are discussed in U.S. patent application serial No.12/604,572, which is incorporated herein by reference. Although it is beneficial if the plurality of devices 5000 in the exemplary lighting system are connected by a wireless mesh network and the controller 112 therein is able to communicate with a remotely located control center and execute the method 4000 (see fig. 16), at a minimum, the controller 112 should be able to control the power to the devices 5000 and maintain a track of the run time; the latter is necessary to ensure long life of the system and methodology of light output.

An exemplary design of a stent similar in function to that described in the above-mentioned U.S. patent application Ser. No.12/910,443 and U.S. patent application Ser. No.11/333,996, incorporated by reference, is shown in FIG. 15B, E-F. Of course, other designs of the bracket are possible and contemplated. Generally, the bracket 600 includes a hinge plate 610, a hinge half 620, and a hinge half 630 (see fig. 15E). The purpose of the bracket 600 is to fix the fixing means 5000 to the rod 81 in the following way: (i) allowing the fixture 5000 to pivot relative to the pole 81 and (ii) allowing wiring to extend from the fixture 5000 to the interior of the pole 81 without exposing the wiring to the elements (e.g., making the lighting system suitable for outdoor use).

As envisioned, each rod 81 includes one or more struts 83 (see fig. 15C), each strut 83 being generally hollow and including a central aperture 84 to receive wiring from the fixture 5000 and an aperture 85 designed to receive a ribbed neck bolt 86 (or similar device). In this example, each strut 83 includes four apertures 85 to accommodate any orientation of the plates 610, although in practice only two bolts 86 are used for any plate 610. In practice, the bolt 86 extends through a crescent-shaped aperture in the portion 611 and engages the nut 618 (see the aforementioned U.S. patent application serial No.11/333,996). The stem 81 also includes a hand hole with an associated cover 82 to allow access to the interior of the stem 81, which is typically hollow, for making the necessary connections to complete the circuit between the driver 111 and the LED201 (e.g., to connect a wiring harness). It should be noted that the exact design of the stem 81 may vary depending on the needs of the application. For example, instead of a strut 83 extending the side of the pole 81 (i.e. projecting forward of the traffic flow), the pole 81 may include a more conventional cross arm at the top of the pole 81. As another example, instead of using existing structural features, custom rods may be designed and installed.

Fig. 15F shows more detail of the stent 600. As can be seen, the hinge half 630 generally includes a plurality of screws with associated washers 637 to secure the portion 631 to the fixture 5000 (e.g., by threading into the holes 62). In practice, grommet 636 receives wiring from fixture 5000 and the wiring's path passes through the main body of portion 631 and into the body of portion 621 where it terminates at connector 626. Connector 626 (which is secured to portion 621 with screw 625) mates with connector 613 when portions 621 and 611 are operatively connected (i.e., when bolt and washer 628 engage internally threaded hex nut 614). In this example, grommet 636 includes space for 12 wires (two wires per driver plus six additional wires for auxiliary devices such as a photovoltaic cell (discussed later)); it will be appreciated that grommet 636 and connectors 626 and 613 may be designed to accommodate any number of wires. In addition to maintaining the trace of the wire, grommet 636-along with member 635-serves to seal portion 631 to fixture 5000. Similar components (see reference numerals 612, 615, 617, 622, and 623) ensure that the parts of the stent 600 seal against each other, and the plate 610 seals against the struts 83, without damaging or exposing the wires to the elements; the sealing member may be made of a typical polymeric material as found in many O-rings (e.g.,) Made of or consisting of a material which can be adapted to the applicationSome other material-and, if appropriate, may be brushed (paint), potted (pot), or otherwise fixed in place (see, in particular, reference numeral 615, where it is removable for very few reasons after mounting the bracket 600).

Another important feature of the mount 600 is that it provides a continuous grounding path so that, particularly in outdoor applications, charge (e.g., charge from lightning strikes) can dissipate into the ground, which is ensured by grounding springs 616, 624 and 634. Of course, this assumes that the fixture 5000, the bracket 600, and the rod 81 are all electrically conductive, but this is not a limitation of the present invention.

To facilitate orientation of the fixture 5000 relative to the rod 81, the fixture 5000 may pivot about an axis extending along the length of the bolt 633. As discussed in U.S. patent application serial No.12/910,443, when the desired orientation is achieved, the bolt 633 and associated washer and nut 627 may be tightened to direct the load through the friction ring 632. Likewise, the securing device 5000 may pivot about a second axis extending along the axis of the ribbed neck bolt 86. As discussed in U.S. patent application serial No.11/333,996, when the desired orientation is achieved, the bolt 86 and associated nut 618 may be tightened.

D. Long term operation

As previously mentioned, for large outdoor lighting systems, such as the large outdoor lighting systems shown in fig. 15A-F and discussed herein, it is not simply impractical to maintain the system in a conventional manner. Shutting down the lane to replace a failed LED requires a high cost, but designing the system to be over-safe (e.g., providing much more light than needed so that when some LEDs are always failed, the system will still produce sufficient light) as is conventionally done also requires a high cost. Even conventional approaches to designing lighting systems beyond safety standards do not ensure long life of LED lighting systems, since the LEDs themselves have not been adequately tested and their performance over a long period of time is at best inferred. So to speak, there is still a need for large outdoor LED lighting systems that operate for long periods of time and are very useful with the data currently available from LEDs. An exemplary method 4000 is shown and currently discussed in fig. 16, which builds on readily available data for an LED to reasonably ensure long life of the LED during specified operating times, and to provide relatively constant light during the operating times.

Manufacturers typically provide a variety of data for LEDs; of most interest are predicted lifetime (EOL) data per the LM-80 standard above (also referred to as L70 data when EOL to the point when the light output was the initial 70% has been determined by the IESNA), power consumption data (e.g., power per LED based on input current), and thermal resistance data. The first step (see reference 4001) is to thermally characterize the fixture in order to understand how a particular fixture and LED combination will affect the life of the LED; in essence, to determine how a particular fixture design acts as a heat sink for a particular LED. In practice, a software package (e.g., qfin4.0, available from Qfinsoft Technology, inc., Rossland, British Columbia, Canada) is used to analyze the thermal characteristics of the fixture 5000, the results combined with the provided power consumption data for the XP-G CreeLED used in the fixture 5000, and to obtain the forward current (I)_f) LED power (W)_L) Power (W) of the fixing device_f) And LED housing temperature (T)_a) The relationship between them. Knowing this relationship and knowing the thermal resistance data of the LED, the junction temperature (T) of the LED can be obtained_j) And I_fFormula of correlation and let T_aAnd I_fThe associated formula.

The next step (see reference 4002) is to characterize the light source photometrically in order to understand how the light output of a particular LED is affected by current and temperature. In practice, XP-G Cree LEDs were tested under various conditions in order to develop T_jAnd I_fAn array correlating the combination of (c) to the luminous flux (Φ); standard photometric test procedures are well known in the art (see, e.g., the IESNA standard LM-79) and are therefore not discussed further herein.

Obtaining information from steps 4001 and 4002 is necessary to help determine the limiting factor of each step 4003 of method 4000. Similar to step 2002 of method 2000, determining the limiting factor requires some knowledge of the application. For example, knowing the lighting requirements of an application determines, at least in part, what type of LED is used and the number of LEDs used. Knowing the type of LED, the number of LEDs, and the power requirements of any other particular application (e.g., requirements for UL column names) determines, at least in part, the type and number of LED drivers. Finally, knowing the performance of each LED driver and the performance of each LED determines, at least in part, the maximum forward current (I) of each LED_FM）。I_FMIs defined as the desired current at the end of the predetermined period of operation required for each XP-G Cree LED in the fixture 5000 (which may vary depending on the application). However, an important aspect of the present invention is somewhat counterintuitive; the number and model of LED drivers must also be selected so that each XP-G Cree LED in the fixture 5000 may exceed I_FMIf necessary; this allows great flexibility in correcting adverse operating conditions, some of which have been discussed.

In general, it is desirable to closely match the driver for a predetermined load in terms of wattage, current, etc. If the driver and load do not match, the driver is less efficient; this concept is well known in the art. Thus, it is counterintuitive to intentionally mismatch the driver and load in the present invention; however, it allows flexibility of the method 4000 (and the invention as a whole) to reasonably ensure that the predetermined number of hours of operation can be reached. In this manner, the LED system as a whole costs more than conventional systems, but less than if the system were to reach EOL prematurely, and all drivers near EOL would be replaced. In practice, the driver chosen is the one that: the driver (I) is dimmable, (ii) is capable of making the LED at I_FM(ii) operation of the LED at I_FM(iii) the above operation, and (iv) the ability to make the LED much lower than I_FM（I_L) Operation of wherein I_LNot less than 50% of the current described above in (iii) (e.g., to limit driver inefficiency). Since it is known that driver efficiency suffers when dimming is achieved by reducing the duty cycle, it is beneficial if the selected driver is capable of linear dimming (i.e. dimming at 100% duty cycle), but this is not a limitation of the present invention.

Is aware of I_LOne can determine the corresponding light output (Φ) based on the matrix obtained in step 4002_L) (ii) a Again, the brand (make) and model of the LED are unambiguous. Use of I_LAs the lower light output threshold, an upper light level threshold (Φ) may be determined taking into account a defined light decay before compensation takes place_H). In an ideal case, the light output is constant; if the light output is allowed to drop to a point where the light is insufficient for the application, there is little benefit in ensuring a long life for the LED lighting system. So to speak, it is impractical to maintain truly constant light; however, the human eye is not adapted to perceive small changes in the illumination level, so a relatively constant light output is allowed. In practice, 2% light attenuation is used to calculate Φ_HThis is not a limitation of the present invention.

Once all limiting factors are identified, a compensation method that ensures long lifetime and relatively constant light in the LED lighting system can be performed (see step 4004). Conceptually, the operation of an LED lighting system is such that each LED sees the same current and the system produces an overall initial light output. Over time, the light output will decrease. When the light output has decreased by a certain amount, compensation will be made by adding a certain amount of current to the LED for a certain period of time. When a certain period of time is reached, another certain amount of current compensation is performed for another certain period of time, and so on until the cumulative operating time of the system reaches a predetermined number of operating hours.

Refer back to method 4000 and use Φ_HAnd I_FMAs constraints for I_fAnd T_JThe formula obtained in step 4001 is solved. I is_fAnd T_JCan be substituted back to T obtained in step 4001_aIn the equations, and using the energy star (ENERGY STAR) exponential equation established by the U.S. Department of energy/Environmental Protection Agency to fill the gaps between data, T is plotted_aThe equation is plotted against the L70 data for a particular make and model of LED (in this example, model XP-G, purchased from Cree) provided by the manufacturer, but other extrapolation methods may be used. The plotted equation essentially yields the case temperature (T) for a particular LED_a) Is a new curve of L70-wherein the x-axis is I_fAnd the y-axis is hours. At this point, one can analyze the new L70 curve to determine the duration using methods well known in the art until the light output is at 98% (i.e., 2% loss rate). Thus, the current supplied to each XP-G LED in the fixture 5000 is set at the calculated I for a period of time determined from the new L70 curve_f. This process (using Φ) once a specified duration has elapsed_HAnd I_FMStarting as a constraint) starts again. Step 4004 is repeated until the sum of each time range equals or exceeds a predetermined number of hours of operation (or some other desired condition occurs).

As designed, the compensation in each step 4004 is made relative to the phase (i.e., the light is attenuated by 2% relative to the case of the light output at the beginning of the extrapolated time range); however, this is but one way of implementing the invention. For example, method 4000 may be varied so that the light decay is measured relative to the initial light output of the system. As another example, instead of a percentage, Φ may be obtained based on a particular number of lumens_H。

As envisaged, the method 4000 is adapted-for a specific combination of fixture and light source-to reasonably ensure a long lifetime of the light source while providing a relatively constant light. It is understood that different types of light sources (e.g., low power metal halide lamps) and differently configured fixtures may be used without departing from aspects of the present invention. Moreover, method 4000 was developed to reasonably ensure long life and relatively constant light for particularly challenging lighting applications where it is not practical to perform periodic or field maintenance physics; however, this is done by way of example and not by way of limitation. For example, it is possible that method 4000 may be updated based on actual light or temperature measurements; these may be done by photocells or thermocouples mounted inside the fixture 5000 and in communication with the controller 112, or by field personnel (e.g., with a light meter and laptop or other device capable of communicating instructions to the controller 112), or even by field personnel taking light measurements, communicating the measurements to a remotely located control center, and the control center communicating the changes to the controller 112.

V. selection and substitution

The present invention may take many forms and embodiments. The above-described embodiments are only a few of them. To give options and alternatives in a sense, a few examples are given below.

Various methods and devices and various alternatives have been described herein. It is noted that these are not intended to be limiting. For example, instead of LEDs, low wattage conventional light sources (e.g., metal halide lamps) may be used. As another example, the lighting application may include the field of sports, as an alternative to a bridge or road. As yet another example, the bolt and threaded blind hole may be replaced with a clamping type mechanism. Also, many of the attachment devices described herein (e.g., bolts, screws, etc.) may be replaced with some other form of attachment (e.g., welding, gluing).

As another example, the design of the securing device 5000 may be different than that shown. Instead of the module bars 50 being bolted into a housing 60 having a stepped cross-section, the plates 50A may be placed in a substantially solid housing; an example of this is shown in fig. 18A and B. In this alternative, the heat sink is more appreciable, but the angle of orientation of each module is predetermined (thereby limiting any field adjustability).

As another example, a number of modules 10 in the fixture 5000 may be mounted to other modules in an opposite manner (e.g., such that the bottom view in fig. 6D becomes a top view) so as to provide upward illumination; this concept is generally illustrated in fig. 17. It can be seen that a large outdoor lighting fixture 1000 is secured to the elevated structure 80. Most of the modules in fixture 1000 are oriented to directly illuminate target area 20 with beam B1; however, a certain number of modules are mounted upside down so as to project light upwardly through beam B2; beam B2 still has some interruption due to the outer shield of the fixture 1000. The large range of orientation angle modules envisaged ensure that the composite beam is suitable for a wide range of applications; in this example, the housing 22 is not directly illuminated (which may not be desirable), but rather the two target areas 20 and the space above the target areas 20 are sufficiently illuminated.

Claims (32)

1. An illumination system for projecting light to produce a customized beam output pattern at, near or on a target area, the customized beam output pattern comprising one or more individual beam patterns, and the illumination system comprising:

a. a rod or other elevating structure;

b. a light fixture adjustable about one or more pivot axes relative to the rod or other elevated structure and having structure for receiving one or more lighting modules;

c. one or more power conditioning components adapted to provide a plurality of power levels to the one or more lighting modules;

d. the one or more lighting modules, once received in the lighting fixture, are adjustable relative to the lighting fixture about one or more pivot axes and adapted to generate the one or more individual beam patterns by selecting one or more of:

i. a light source;

a shield;

a lens;

a reflective surface; and

v. a diffuser.

2. The lighting system, as set forth in claim 1, wherein the power adjustment component is adapted to provide power to the one or more lighting modules according to a predetermined profile for a predetermined length of time.

3. The lighting system, as set forth in claim 2, wherein a relatively constant light output of the one or more lighting modules is maintained for the predetermined period of time.

4. The illumination system of claim 3, wherein the relatively constant light output comprises a light output that is perceivable as constant by an unaided human eye.

5. The lighting system, as set forth in claim 2, wherein the predetermined profile for providing power to the one or more lighting modules is based on (i) a thermal analysis of the lighting fixture and (ii) a photometric analysis of one or more light sources.

6. The lighting system, as set forth in claim 1, further comprising an adjustable bracket adapted to provide pivoting of the lighting fixture relative to the rod about the one or more pivot axes.

7. The lighting system of claim 6, wherein the internal wireway is established by one or more internal cavities in (i) the lighting fixture, (ii) the adjustable bracket, and (iii) the pole or other elevated structure.

8. The illumination system of claim 1 wherein the customized beam output pattern comprises task illumination and upward illumination.

9. The lighting system, as set forth in claim 1, wherein the lighting module comprises:

a. a pivot joint having a mounting portion on which one or more light sources are mounted and a pivot portion adapted to (i) provide pivoting about the one or more pivot axes relative to the light fixture and (ii) be received by the light fixture;

b. a lens having a light emitting surface and a surface adjacent to the light source;

c. a housing mountable to the pivot joint and having an aperture for receiving and positioning the lens such that the surface of the lens adjacent the light sources encapsulates the one or more light sources;

d. a visor mountable to the housing and having:

i. an aperture for propagating a portion of the light from a light emitting surface of the lens;

a reflective surface for redirecting a portion of the light from the light emitting surface of the lens; and

a shape designed to block a portion of light from a light emitting surface of the lens at a predetermined angle.

10. The lighting system, as set forth in claim 9, wherein the visor further comprises a plurality of shape features designed to absorb a portion of the high angle of incidence light from the light emitting surface of the lens.

11. A method of assembling a light fixture designed to produce a customized beam output pattern at, near or on a target area, the customized beam output pattern comprising one or more individual beam patterns, the method comprising:

a. orienting a fixture housing relative to the target area, the fixture housing having an outer surface, an opening, and an interior, the interior having a surface of rotation;

b. mounting one or more lighting modules on a module bar at predetermined locations on the module bar, the module bar having a curvature that matches a rotating surface of an interior of the fixture housing;

c. orienting each of the one or more lighting modules in a predetermined direction such that light projected from each light emitting module generates at least one individual light beam pattern; and

d. mounting a module strip containing one or more oriented lighting modules in an oriented fixture housing such that the module strip abuts an inner surface of the fixture housing.

12. The method of claim 11, wherein the interior of the fixture housing comprises one or more additional rotating surfaces.

13. The method of claim 12, further comprising: installing one or more additional module bars containing oriented lighting modules in the oriented fixture housing, the one or more module bars having a curvature that matches one or more additional surfaces of rotation of an interior surface of the fixture housing.

14. The method of claim 11, further comprising mounting a lens and a complementary gasket over an opening of the fixture housing to seal an interior of the fixture housing.

15. The method of claim 14, further comprising: a shield is mounted on an outer surface of the fixture housing such that the shield at least partially surrounds the lens.

16. The method of claim 11, wherein each individual beam pattern at least partially overlaps one or more adjacent individual beam patterns.

17. A method of ensuring a number of hours of operation in a lighting system according to claim 1, the method comprising:

a. thermally characterizing one or more portions of the lighting system;

b. photometrically characterizing one or more portions of the illumination system;

c. powering, by the power conditioning component, the lighting system at an initial power level; and

d. incrementally increasing power to the lighting system according to a predetermined curve until a guaranteed number of hours of operation the lighting system has been operated.

18. The method of claim 17, wherein the incremental increase in power is designed to compensate for light loss to maintain a minimum light output level.

19. A lighting module for use in a lighting fixture, comprising:

a. an assembly of a plurality of individual layers, the assembly when assembled not exceeding about a few inches in length, width and depth, the plurality of individual layers comprising;

i. a base layer;

an optical element layer;

a light source layer between the base layer and the optical element layer;

b. the light source layer has

i. The base layer side;

an optical element layer side having a light source mounting structure to removably receive and align at least one solid state light source relative to the light source layer;

at least one solid state light source removably mounted in the light source mounting structure, each light source having an optical axis;

a light source layer alignment structure;

c. the base layer has

i. A fixture mounting side including a mounting interface that allows at least one degree of freedom of movement of a base member relative to a mounting location on the lighting fixture; and

a light source layer side having an alignment structure complementary to the light source layer alignment structure to align the light source layer relative to the base layer;

d. the optical element layer has

i. A light source layer side having an optical element layer alignment structure to align the optical element layer with respect to the light source layer and the base layer;

an outer side;

a through hole between the light source layer side and the outer side, the through hole being aligned with and allowing passage of an optical axis of each light source on the light source layer when the optical element layer is assembled relative to the light source layer;

a receptacle having a structure to receive an optical element and align the optical element relative to the through-hole;

v. an optical element removably positioned in the receptacle.

20. The lighting module of claim 19, wherein the lighting module is combined with a plurality of additional lighting modules in the mounting location in the lighting fixture, thereby allowing independent selection of light sources, optical elements, and orientations of each module.

21. The lighting module of claim 20 further comprising a plurality of the lighting fixtures in an array on a support structure to allow coordinated illumination of one or more target areas.

22. The lighting module of claim 21, further comprising a plurality of said arrays to allow coordinated illumination of said one or more target regions.

23. The lighting module of claim 19, wherein the at least one degree of freedom of motion comprises a pitch motion in a first plane.

24. The lighting module of claim 19, wherein the at least one degree of freedom of motion comprises a pitch motion in a first plane and a horizontal motion in a second plane.

25. The lighting module of claim 19 further comprising a visor having a proximal end removably mountable to visor mounting structure on the optic layer and a distal end extending away from the proximal end.

26. The lighting module of claim 25 wherein one or both of the visor and the optic layer includes a mounting structure including a selectable adjustment mechanism enabling adjustment of the visor with respect to the optic layer in at least one degree of freedom of movement.

27. The lighting module of claim 26 wherein the at least one degree of freedom of movement of the visor relative to the optic layer is rotation about the through hole of the optic layer.

28. The lighting module of claim 25 wherein the visor comprises at least one of:

a. a reflective portion on an inner side;

b. a light absorbing surface on portions on the inner or outer side;

c. a light capturing texture or structure on the outer side.

29. The lighting module of claim 19, further comprising a fastening member associated with the layers of the assembly to hold or clamp the layers together, but to allow quick and easy disassembly of the layers for maintenance, repair or replacement of the layers, the light source or the optical element.

30. The lighting module of claim 19, further comprising a module circuit operatively connected to the light source.

31. The lighting module of claim 30 further comprising a control circuit in operative connection with the module circuit.

32. The lighting module of claim 31, wherein the control circuit comprises one or more of the following components:

a. an adjustable drive current component;

b. a remote control unit;

c. a sensor component to sense a condition at or near the light source or an operating parameter of the light source.