English:
[0002] Due to the increasingly widespread quest for energy savings, light emitting diodes (LEDs) have become more and more popular in the lighting industry. LEDs are so popular because of their small size, fast on-time and quick on-off cycling, relatively cool light, and high efficiency. LEDs present challenges for luminaire manufacturers, however, with respect to heat and glare.
[0003] In contrast to most other currently available light sources, LEDs radiate very little heat in the form of infrared radiation. Waste energy is dispersed as heat through the base of the LED. Typically, LED luminaires incorporate a plurality of LEDs and the heat given off can be substantial. Over-driving an LED in high ambient temperatures may result in overheating the LED array, eventually leading to device failure. Adequate heat dissipation is desirable to maintain the long life of which LEDs are capable.
[0004] For the most part, LED luminaires deal with the heat dissipation issue in one of two ways. Some luminaires incorporate air vents and complex heat sinks, sometimes involving fins on the exterior of the housing where they are visible to the consumer and aesthetically unappealing and often requiring complicated internal housing to allow for weatherproofing. Moreover, in many cases, because the number and size of LEDs affects heat dissipation requirements, the configuration and dimensions of the finned housing vary according to the number and size of the LEDs, which increases stocking requirements, makes it more difficult to substitute fixtures if lighting needs change, and increases architectural planning considerations. Those issues create a deterrent for businesses seeking to transition from existing non-LED luminaires to the greater efficiencies provided by LEDs.
[0005] Other luminaires simply do not provide adequate thermal management. If such fixtures are used for long periods of time, heat becomes a problem resulting in a likely shortening of the LED lifetimes and potential serious color shift of the devices.
[0006] Many LED luminaires also have problems with glare and/or the production of multiple shadows, since the light exiting each individual light-emitting diode is focused forward and not diffused. Traditionally, LED arrays are positioned similarly to other lamps in luminaires, such that the light flows directly from the lamp through the face of the fixture. This positioning allows for maximum light output, but it disregards the discomfort of the resulting glare. Generally when an LED luminaire is to be used as area lighting rather than point-source lighting, the issues of glare and shadowing have been treated in the manner typical of non-LED luminaires: by incorporating reflectors behind the lamp to diffuse the light and designing the housing to allow for the reflectors. Alternatively or in addition, a diffuser may be used.
[0008] Figures 1A and 1 B are assembled views of an LED luminaire in accordance with one embodiment of the thermal management system and of the anti-glare system.
[0009] Figure 2 depicts a disassembled, exploded view of the luminaire embodiment depicted in Figures 1A-1 B.
[0010] Figure 3 depicts an exploded, cutaway view of an embodiment of an LED module and housing.
[0011] Figure 4 is a cross sectional view of the luminaire embodiment depicted in Figure 1 B at the line shown.
[0012] Figure 5 is a cross sectional front view of the luminaire embodiment depicted in Figure 1 A at the line shown.
[0013] Figure 6 depicts a disassembled, exploded view of a second luminaire embodiment.
[0014] Figure 7 depicts a disassembled, exploded view of a third luminaire embodiment.
[0015] Figures 1A-5 depict an LED luminaire 10 in accordance with one embodiment of the inventive thermal management system and inventive anti-glare system.
[0016] As depicted in Figures 1A-5, the LED luminaire 10 of the depicted embodiment is a traditional wall pack unit for area lighting, which has been internally modified to provide a highly conductive thermal path to minimize LED junction temperatures. This design results in minimal temperature rise for the one or more LEDs 70, thereby insuring higher lumen maintenance and more stable correlated color temperature over the life of the product. Using a traditionally shaped and sized housing 20 offers end users the ability to enjoy the energy savings of LED technology without having to modify existing surroundings to accommodate new housing designs.
[0017] The luminaire housing 20 is preferably a wet location enclosure for protection of electrical components and connections. In the depicted embodiment, the housing consists of two parts, a back housing 24 and a front face frame 22. The front face frame 22 has an aperture 25 and a top side 26. The front face frame 22 may be connected to the back housing 24 by securing fasteners 27, 27', 28, 28' with pins 29, 29'. It is preferred that the back housing 24 and front face frame 22 be of die cast aluminum, but the back housing 24 and/or the front face frame 22 could be manufactured from other materials or in other ways. Aluminum is the presently preferred material because it works well for the die casting process, and it also is lower in cost than other conventionally available alternatives, which include zinc, magnesium, and copper. Aluminum is further preferred due to its high thermal conductivity, an important aspect to assist in heat dissipation.
[0018] The back housing 24 may be used as the primary means for mounting the luminaire 10 to the desired location. In the depicted embodiment, it also houses the LED driver 54 and main reflector 42.
[0019] The front face frame 22 may be used as the means to mount a diffuser 30 and left and right side reflectors 44, 46 within the luminaire 10. The frame 22 further acts as a heat transfer mechanism to the exterior environment and provides the necessary mounting angle for the LED module 100 (described below) to achieve the preferred light distribution to minimize glare.
[0021] As already noted above, the LED module 100 is mounted to the top side 26 of the housing 20. This location is a component of the thermal management system as part of how the system utilizes natural convection. The LED module 100 in the depicted embodiment comprises of three main parts - one or more LED arrays 50, 50', one or more primary thermal interfaces 60, 60', and a secondary thermal interface 62. The LED arrays 50, 50' are printed circuit boards 52 containing one or more LEDs 70. Any shape or number of LEDs 70 may be used on the LED arrays 50, 50'. Further, the circuit board 52 could use multi-chip LEDs 70, use single or multi-array configurations, or contain secondary optics placed in conjunction with the LEDs to modify the resulting light distribution.
[0022] As shown more specifically in Figure 3, the inventive thermal management system allows for optimum heat dissipation through a multi-layer heat sink. An LED array 50 is comprised of an LED 70 and printed circuit board (not separately shown). When activated, the LED 70 generates heat at its base. This inventive thermal management system utilizes both natural convection and conduction first by positioning the LED 70 so that the heat in its base is directed generally upward. Accordingly, the heat of the LED 70 first passes upward through the board 52. To allow for the most efficient heat dissipation, the board 52 may have a metal core, such as aluminum or copper.
[0023] Referring back to Figures 1 A, 1 B, and 2, the heat then continues generally upward, passing through the primary thermal interfaces 60, 60'. These interfaces 60, 60' at least partially fill the gaps created when mounting the LED arrays 50, 50' to the secondary thermal interface 62 or to the front face frame 22 and are generally the same size as the arrays 50, 50'. The primary interfaces 60, 60' may be thermally conductive gap filler, such as an ultra soft acrylic elastomer, or, in the alternative, thermal grease, thermal tape, thermal adhesive, or some other material suitable to create a thermal path for heat dissipation, The main requirement is to use materials that are more heat-conductive than air.
[0024] The secondary thermal interface 62 as shown in the embodiments depicted in Figures 1A - 5 provides for a continued upward conduction path as well as a secondary, substantially horizontal path for heat dissipation. In the embodiment shown, the secondary thermal interface 62 is mounted to the front face frame 22 and may be made of aluminum. Other suitable materials, such as copper or other materials more heat-conductive than the ambient air, may be used in the alternative. Greater heat conductivity will improve performance. This interface 62 provides a direct path for heat dissipation from the LED circuit board 52 to the housing 24, which then dissipates the heat to the ambient air. In addition, a second path is provided from the LED circuit board 52 to the interface 62 that provides a broad surface to dissipate heat to the air enclosed by the housing 20. This air, in turn, conducts the heat to the housing 20 via natural convection from whence it is conducted to the air external to the housing 20. Due to the effectiveness of this dual path for heat dissipation, there is no need for vents, fins, or complex weatherproofing.
[0025] Additionally, using the secondary thermal interface 62 for mounting the LED arrays 50, 50' provides an easily modified mounting solution rather than attaching the LED arrays 50, 50' directly to the housing 20. If the LED arrays 50, 50' were mounted directly to the housing 20, any change in the size or type of arrays 50, 50' would potentially mean modifying the housing 20 and, thus, the die cast molding. Changing hole sizes or positions in the secondary thermal interface 62 is much easier and can be accomplished in less time and at lower cost.
[0026] Figures 6 and 7 depict alternate embodiments of the inventive luminaire 10. Figure 6 depicts an embodiment of the inventive luminaire 10 in vandal-resistant housing. Figure 7 depicts an embodiment of the inventive luminaire 10 in floodlight housing. Each comprises a back housing 24, one or more LED arrays 50, 50', 50", 50"', LED driver 54, one or more primary interfaces 60, 60', 60", 60"', and a secondary thermal interface 62. The floodlight Figure 7 also includes a front face frame 22, and the vandal-resistant Figure 6 includes a front face diffuser 31. As with the embodiment depicted in Figures 1A-5, these alternate embodiments also utilize a combination of natural convection and conduction. With the one or more LED arrays 50, 50', 50", 50"', stacked with one or more primary interfaces 60, 60', 60", 60"'and a secondary thermal interface 62, and then mounted to the back housing 24, both a conductive and convective thermal path to the housing are provided. Optionally, the secondary thermal interfaces 62, 62' may also serve to reflect the light produced by the LED arrays 50, 50', providing a stronger light output.
[0027] As shown in Figures 1A-5 of the first embodiment, the reflector system 40, shown in the depicted embodiment as three separate reflectors 42, 44, 46, is used to redirect the light output from the LED arrays 50, 50' into the prismatic glass of the diffuser 30. The reflector system 40 may be manufactured of formed aluminum, steel, or other material suitable for the purpose and finished with a suitable optical coating (e.g., polished, reflective paint, etc.). The reflectors 42, 44, 46 may be combined into a single reflector, two reflectors, or other combinations of reflectors to achieve a similar result.
[0028] As specifically shown in Figures 4 and 5 of the first embodiment, the position of the one or more LED arrays 50, 50' on the top side 26 of the luminaire 10 in combination with the reflector system 40 creates an optical path resulting in an indirect light source that minimizes glare, while providing a uniform distribution of light, unlike traditional LED luminaires. Specifically, the LED arrays 50, 50' are secured to the top side 26 of the luminaire 10. The one or more LEDs 70 on the LED arrays 50, 50' have a distribution pattern such that they produce light in a cone 32, 32' at approximately 120 degrees from the orthogonal. Because the arrays 50, 50' are aimed substantially toward the bottom portion 21 of the housing 20, they deliver the majority of the light at lower angles. The reflector system 40 also directs the resulting light from the arrays 50, 50' toward the bottom portion of the housing. The prisms within the diffuser 30 then redirect the light exiting the fixture such that the resultant light in the glare zone (80 to 90 degrees from the downward direction) is minimized. While this combination does cause some loss in light output, the lack of glare from the luminaire 10 is a valuable and so far underappreciated advantage.
[0029] The foregoing details are exemplary only. Other modifications that might be contemplated by those of skill in the art are within the scope of this invention, and are not limited by the examples illustrated herein.

中文:
[0002]由于日益广泛地追求节约能源,在灯具行业中,发光二极管(LED)变得越来越受欢迎。LED如此受欢迎是因为其尺寸小、接通时间短暂且开关循环迅速、发出的光相对冷,以及其效率较高。但是,目前LED对照明器制造商带来困难的是LED的热量和眩光。
[0003]与大多数其它的当前可用光源相比,LED发射出很少的红外线辐射形式的热量。废能作为热量通过LED的基底(base)耗散掉。通常,LED照明器结合多个LED,并且放出的热量可能相当大。在高环境温度下过度驱动LED可导致LED阵列过热,最终导致装置发生故障。希望有充分的散热,以将LED的可用寿命维持成较长。
[0004]在大多数情况下,LED照明器通过两种方式中的一种来解决散热问题。一些照明器具有通风口及复杂的散热器,有时在壳体外部上具有散热片,这些散热片对于消费者是可见的且不美观,通常需要复杂的内部壳体来防风防雨。此外,在许多情况下,由于LED的个数和尺寸影响散热需求,带散热片的壳体的结构和尺寸依据LED的个数和大小而改变,这提高了库存要求,使其在灯具需要改变时更加难以替换固定物,并且增加了建筑规划的考虑因素。这些问题对于试图将现有的非LED照明器转换成LED以获得LED所提供的更高效率的企业造成妨碍。
[0005]其它照明器根本未提供足够的热管理。如果这样的固定物被长时间使用,热量变成了导致可能缩短LED寿命和有可能使装置严重色偏(color shift)的问题。
[0006]由于从各个单独发光二极管发出的光线向前聚焦而不扩散,所以许多LED照明器还存在关于眩光和/或产生多个阴影的问题。传统上,LED阵列与其它的照明灯类似地放置,使得光线从灯直接穿过固定物的面。这种定位能够实现最大的光输出,但其忽略了由此引起的眩光带来的不适。大体上,在LED照明器要用作面光源而不是点光源时,眩光和阴影的问题则可以典型的非LED照明器的方式处理,即:通过在灯的后面结合反射器以使光线漫射(diffuse),以及将壳体设计成能够为反射器创造条件。备选地或额外地,也可使用漫射器(diffuser)。
[0008]图1A和图1B是依据热管理系统和抗眩光系统的一个实施例的LED照明器的组装图。
[0009]图2描绘了图1A至图1B中所描绘的照明器实施例的已拆开的、分解视图。
[0010]图3描绘了LED模块和壳体的实施例的分解的剖视图。
[0011]图4是在图1B中所示直线处描绘的照明器实施例的横截面视图。
[0012]图5是在图1A中所示直线处描绘的照明器实施例的横截面正视图。
[0013]图6描绘了第二照明器实施例的已拆开的、分解视图。
[0014]图7描绘了第三照明器实施例的已拆开的、分解视图。
[0015]图1A至图5描绘了一种依据本发明的热管理系统及本发明的抗眩光系统的一个实施例的LED照明器10。图6和图7描绘了本发明的热管理系统的附加实施例。
[0016]如图1A至图5所描绘的,所描绘的实施例中的LED照明器10是用于面光源的传统墙挂单元,已经对其进行了内部改变,以提供高导热的路径来最大程度降低LED结温度。这种设计导致最大程度降低一个或多个LED70的温度升高,从而确保在产品寿命期间保持较高的流明和稳定的相关色温。使用传统形状和大小的壳体20使得最终用户能够享受到由LED技术带来的能源节省,而不必改变现有围绕物来适应新的壳体设计。
[0017]照明器壳体20优选地是湿式定位外壳(wet location enclosure),用于保护电气元件和连接。在所描绘的实施例中,壳体包括两个部分:后壳24和正面框架22。该正面框架22具有开口25和顶面(top side)26。通过用销29、29’将紧固件27、27’、28、28’固定,可将正面框架22连接至后壳24。优选地,后壳25和正面框架22由压铸铝(die cast aluminum)制成,但后壳24和/或正面框架22也可由其它材料或通过其它方式制成。铝是当前优选的材料,这是因为其可被很好地用于压铸处理,并且其还比其它常规可用的备选材料(包括锌、镁,以及铜)的成本更低。铝进一步成为优选的原因在于其导热性高,这是有助于散热的重要方面。
[0018]后壳24可被用作用于将照明器10安装在期望位置上的主要器件。在所描绘的实施例中,其还容纳有LED驱动器54以及主反射器42。
[0019]正面框架22可被用作用于将漫射器30和左右侧反射器44、46安装在照明器10内的装置。框架22进一步起到传热机构的作用将热量传输至外部环境,并为LED模块100提供了必要的安装角度(在下文中说明),以实现优选光分布,从而最大程度降低眩光。
[0021]正如以上已经提到的,LED模块100被安装在壳体20的顶面26上。这种定位是热管理系统的组成部分,是该系统如何利用自然对流的一部分。所描绘的实施例中LED模块100包括三个主要部分—一个或多个LED阵列50、50’、一个或多个初级热界面60、60’,以及次级热界面62。LED阵列50、50’为包含一个或多个LED70的印刷电路板52。在LED阵列50、50’上可使用任意形状或个数的LED70。进一步地,电路板52可使用多芯片LED70、使用单阵列或多阵列配置,或者包含与LED结合放置的次级光学器件,来改变所产生的光分布。
[0022]正如在图3中更具体地示出的,本发明的热管理系统可通过多层散热器实现最佳散热。LED阵列50包括LED70和印刷电路板(未单独示出)。在被启动时,LED70在其基底处生热。本发明的热管理系统通过对LED70进行定位,利用自然对流和传导,使得LED基底上的热量大体上向上传导。据此,LED70的热量首先向上经过板52。为了实现最高效的散热,板52可具有诸如铝或铜的金属芯子。
[0023]返回参考图1A、图1B和图2,热量接着继续大体上向上传播,经过初级热界面60、60’。这些界面60、60’至少部分地填充在将LED阵列50、50’安装至次级热界面62或正面框架22时所产生的间隙,并大体上与阵列50、50’大小相同。初级界面60、60’可以是导热的间隙填充物,诸如超软丙烯酸弹性物(acrylic elastomer),或者在备选方案中为导热膏、导热胶带、导热胶,或可适于产生用于散热的热路径的一些其它材料。主要的要求是使用比空气的导热性更强的材料。
[0024]如在图1A至图5中所描绘的实施例中所示出的次级热界面62为散热提供了继续向上的传导路径以及次级的基本上横向路径。在所示出的实施例中,次级热界面62被安装至正面框架22,并可由铝制成。而在备选方案中也可使用其它适当材料,诸如铜或者比环境空气的热传导性更强的其它材料。更强的热传导性可改善性能。这种界面62为从LED电路板52到壳体24的散热提供了直接的路径,其然后将热量散至环境空气中。此外,提供了从LED电路板52至界面62的第二路径,该界面62提供了用于将热量散至壳体20包围的空气中的板表面。这些空气继而通过自然对流使得热量传导至壳体20,从此处其被传导至壳体20外部的空气中。由于这种双路径的高效散热性,就不再需要通风口、散热片或复杂的防风防雨性了。
[0025]此外,使用次级热界面62用于安装LED阵列50、50’而不是将LED阵列50、50’直接附着至壳体20提供了易于修改的安装方案。如果将LED阵列50、50’直接安装至壳体20,阵列50、50’的大小或种类的任何改变都潜在地意味着要更改壳体20,并且因此,改变压铸模型。改变次级热界面62上的孔的大小或位置更为容易得多,并能够以更短的时间和更低的成本来完成。
[0026]图6和图7描绘了本发明的照明器10的备选实施例。图6描绘了在抗破坏壳体中的本发明的照明器10的实施例。图7描绘了在泛光灯壳体中的本发明的照明器10的实施例。每一种都包括后壳24、一个或多个LED阵列50、50’、50”、50’’’、LED驱动器54、一个或多个初级界面60、60’、60”、60’’’,以及次级热界面62。泛光灯式的图7还包括正面框架22,而抗破坏式图6包括正面漫射器31。如图1A至图5中所描绘的实施例,这些备选实施例还利用自然对流和传导的组合。通过使用一个或多个LED阵列50、50’、50”、50’’’,与一个或多个初级界面60、60’、60’’、60’’’以及次级热界面62层叠在一起,且然后被安装至后壳24,提供了通向壳体的具有导热性和热对流性的路径。可选地,次级热界面62、62’还可起到对由LED阵列50、50’产生的光线进行反射的作用,提供了更强的光输出。
[0027]如在图1A至图5中第一实施例所示出的,反射器系统40,在描绘的实施示例中被示出为三个独立的反射器42、44、46,被用于将从LED阵列50、50’输出的光重新定向至漫射器30的棱镜玻璃中。该反射器系统40可以是由成型铝、钢,或适用于此目的的其它材料制造的,并用适当的光学涂层做表面处理(例如,抛光、刷反光漆,等)。可将反射器42、44、46合并到单个反射器、两个反射器,或其它反射器组合中以达到相似结果。
[0028]如在图4和图5中的第一实施例具体示出的,一个或多个LED阵列50、50’在照明器10的顶面26上的定位与反射器系统40相结合生成了光学路径,产生最大程度降低眩光的间接光源,同时提供了均匀的光分布,与传统LED照明器不同。特别是将LED阵列50、50’固定至照明器10的顶面26。LED阵列50、50’上的该一个或多个LED70具有使得它们产生与垂直线(orthogonal)成大致120度的锥形光32、32’的分布模式。由于阵列50、50’基本上旨在朝向壳体20的底部21,所以它们以较低的角度提供大部分的光。反射器系统40也将来自阵列50、50’的合成光导引成朝向壳体的底部。在漫射器30内的棱镜然后改变退出固定物的光线的方向,使得在眩光区(与向下的方向成80至90度)中的合成光在最大程度上降低。虽然这种组合确实导致了光输出的一些损失,但是从照明器10中除去眩光是很有价值的,并且至今具有不可估量的优势。
[0029]前面的详细说明仅是示例性的。那些本领域技术人员可设想到的其它变化在本发明的范围内,且不限于本文所说明的示例。