CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit under 35 ET.S.C. § 119(e)(1) of ET.S. Provisional Application No. 62/682,705, filed on June 8, 2018, which is incorporated by reference herein.

FIELD OF TECHNOLOGY

The present technology relates to modular luminaires with modules that are thermally coupled to conduct heat, in particular to luminaires with recessed housings that provide good heat dissipation from light sources such as light-emitting diodes (LEDs).

BACKGROUND

Numerous recessed luminaires exist that are destined for retrofit upgrades to solid-state lighting (SSL) with LED bulbs of various formats or other non-bulb like-light engines. Although temperature and heat loads are moderate, heat dissipation from SSL sources needs to be managed carefully particularly in confined recessed luminaires, because, compared to incandescent and various other light sources, SSL sources provide substantially no radiative heat-loss mechanisms. SSL retrofit solutions typically used today rely on convection or provide thermal design with limited heat conduction. Examples are described in United States Patent Nos. 9,709,253 and 7,766,512, and in United States Patent Publication No. 2011/0261572, for example.

In various recessed luminaires, replacement light engines include heat sinks configured to release heat into the space surrounded by some form of metal housing provided by the luminaire. This makes such light engines bulky, heavy and expensive mostly due to the added heat sink. Despite efforts, their heat sinking capabilities are poor since much of the heat from the light engine has to transfer via convection through the air-filled confined space within the housing before it can reach the ambient environment. Heat transfer via natural convection with gaseous environments provides poor heat transfer rates, typically only 2 to 5 W/m/m/K compared to heat conduction with one to three orders of magnitude higher heat transfer rates.

To avoid such bottleneck situations in retrofit situations, removing the housing can help improve heat dissipation. Removal, however, may not be desirable as it adds extra cost, requires some form of replacement and typically causes / requires renovations of the plenum/ceiling. Even then, the system may provide inferior heat sinking. As such there is a need for a better solution to heat management in recessed luminaires, in particular in retrofit situations.

SUMMARY

According to aspects of the present technology, there is provided a modular luminaire with heat- conductive coupled modules.

In one aspect, a light engine is configured to couple with a heat sink having an aperture. Here, the light engine includes (i) one or more light-emitting elements (LEEs); and (ii) a frame thermally coupled with the one or more LEEs. The frame includes multiple contact elements arranged in an annular configuration and configured to resiliently engage an inside of the heat sink when inserted in the aperture and conduct heat to the heat sink from the LEEs during operation.

The foregoing and other embodiments can each optionally include one or more of the following features, alone or in combination. In some embodiments, the contact elements can protrude from the frame within a plane perpendicular to an axis of the aperture of the heat sink. In some embodiments, the contact elements can be arranged in radially opposing pairs. In some embodiments, one or more of the contact elements can be pivotally coupled with the frame perpendicular to an axis of the aperture of the heat sink. In some cases, the light engine can have a latch including a slider. The slider is configured to slide perpendicular to the axis of the aperture of the heat sink between a retracted configuration and an extended configuration. Here, the slider is clear of the pivotal coupling in the retracted configuration, and extends across the pivotal coupling in the extended configuration. As such, the latch is configured to resiliently bias the pivotally coupled contact elements within a plane perpendicular to the axis of the aperture of the heat sink. Optionally, the LEEs can be arranged on a first side of the frame, and the latch is arranged on a second side of the frame opposite the first side. Also optionally, the slider can b e resiliently biased into the extended configuration.

In some embodiments, the contact elements can have flanges shaped to abut the inside of the heatsink. In some cases, the flanges can have L-shaped or T-shaped profiles within one or more sectional planes parallel to an axis of the aperture of the heat sink. In some cases, one or more of the flanges can have resilient arc shapes extending annularly within a plane perpendicular to an axis of the aperture from respective center portions of the flanges. Optionally, the arcs can have curvatures smaller than the curvature of the aperture within said plane.

In another aspect, a luminaire includes the heat sink and any one of the previous embodiments of the light engine. Here, the light engine is inserted in the aperture of the heat sink.

The foregoing and other embodiments can each optionally include one or more of the following features, alone or in combination. In some embodiments, the heat sink can be provided by a housing of the luminaire recessed in a ceiling. The details of one or more implementations of the technologies described herein are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the disclosed technologies will become apparent from the description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective cut-away schematic view of a luminaire according to the present technology.

FIG. 2 shows a perspective schematic view of the light engine of the luminaire of FIG 1.

FIG. 3 shows another perspective schematic view of the light engine of the luminaire of FIG 1.

FIG. 4 shows a perspective cut-away schematic view of the luminaire of FIG 1 during insertion of the light engine.

FIGs. 5 A-5D show side views of other embodiments of the light engine of the luminaire of FIG. 1

FIG. 6A shows a side view of a light engine, which can be used in conjunction with the luminaire of FIG. 1, corresponding to an open configuration thereof.

FIG. 6B shows a side view of the light engine of FIG. 6 A corresponding to a locked configuration thereof.

Reference numbers and designations in the various drawings indicate exemplary aspects, implementations of particular features of the present disclosure. DETAILED DESCRIPTION

The present technology provides a luminaire with a modular architecture including a light engine configured to be inserted into an aperture of an external heat sink in such a way that it allows good heat dissipation from the light sources via heat conduction to the external heat sink. The heat sink can be provided by one or more components that are part of or coupled with the luminaire such as a housing, reflector or other structure that can suitably support the light engine mechanically and sink heat. As such the heat sink is thermally coupled with the light engine and generally referred to as being“external” thereto. Depending on the implementation, the heat sink may be considered external or internal to the luminaire itself. The light engine can be configured to couple thermally and mechanically with correspondingly shaped apertures. Apertures can be round, circular, elliptical, rectangular, polygonal or otherwise shaped.

It is noted that the present technology seeks to provide good thermal conductivity and heat transfer via intimate mechanical contact provided by resilient biasing between a light engine and a heat sink that can be configured to allow ready disassembly and/or replacement and allow utilization of certain luminaire housings as heat sinks. The technology can be employed in new and retrofit installations.

The technology can be employed in SSL retrofits of luminaires that are traditionally conceived for use with incandescent, gas discharge or other light sources and equipped with heat sinks or heat shields to protect ceilings and walls from the heat of the lamps during operation and/or shield the light source from ambient outdoor or indoor conditions, for example. The technology can also be employed in luminaires configured for new installations. Heat sinks can be provided by metallic or other components, housings, poles, posts, reflectors or other components of or external to the luminaire.

FIGs. 1 and 4 show perspective cut-away views of an example luminaire 101 according to the present technology. FIG. 1 shows the example luminaire 101 in an assembled configuration and FIG. 4 during assembly. The luminaire 101 includes an example metallic housing 105 and an example light engine 100 including LEDs 110. The light engine 100 is configured to employ the housing 105 as an external heat sink when assembled. The housing 105 in this example is configured for recessed installation in a ceiling or wall and has a can or pot-like format.

Generally, the luminaire 101 includes electrical connections (not illustrated in the schematic view) to supply power to the light engine 100. Such electrical connections can include suitable plug-in wiring, a screw or bayonet socket or other electrical connections to operatively couple the light engine 100 to external power and/or a driver. Depending on the implementation, a driver may be built into the light engine 100.

FIGs. 2 and 3 show perspective schematic views of the light engine 100. FIG. 2 shows a first side of the light engine 100, here the side onto which the LEDs 110 are disposed. FIG. 3 shows a second side, opposing the first side. The example light engine 100 has a generally planar geometry. Other example light engines can have other geometries, for example cylindrical or bulb-like formats. The light engine 100 includes a frame 140 configured to operatively support and receive heat from the LEDs 110. The light engine 100 is configured to provide a good thermal connection between a heat transfer surface 135a of a contact element 135 and the LEDs 110. The frame 140 is configured to guide heat away from the LEDs 110. For this purpose, the frame 140 includes one or more suitable components for heat dissipation or is configured as a whole to do so. For example, the frame 140 may include a metal-core printed circuit board with additional components such as aluminum vias, or other heat conductive elements.

In the example illustrated in FIGs. 1-4, the frame 140 includes two contact elements 133 and 135 of different size. The contact element 133 in combination with the remainder of the frame 140 forms a hinge about pivot 120. Contact element 135 is configured with a larger heat transfer surface 135a provided by a flange that extends in an arc/annular manner from the light engine 100. In this example, the contact element 135 has a flange with an L-shaped profile in sectional planes parallel to an axis 102 of the aperture of the heat sink. The flange provides resilience to the hinge formed by the pivot 120. Here, the axis 102 is parallel to the z-axis. In the example illustrated in FIGs. 1- 4, the contact element 133 has no flange but it can have a flange in other implementations.

Depending on the implementation, contact elements can have flanges with symmetrical or asymmetrical T-shaped profiles which may stabilize the light engine 100 differently compared to flanges with L-shaped profiles and make the system suitable for different installed orientations, vibrational loads or other operational aspects. Sectional views of example light engines lOOa to lOOd are shown in FIGs 5 A to 5D, respectively. The example light engines lOOa to lOOd have first and second contact elements l33a to l33d and l35a to l35d with various configurations of L- shaped and T-shaped flanges. The flanges are shaped to resiliently bias the contact elements of the respective light engines lOOa to lOOd into a planar alignment when installed. Here, the contact elements l33a to l33d in combination with the remainder of the frame 140 form respective hinges about the pivots l20a to l20d. In some implementations, flanges in different contact elements may have like shapes or different shapes. Moreover, flanges in different contact elements can have different orientations, for example some contact elements may have L-shaped flanges oriented upwards while others have downward oriented L-shaped flanges. Differently oriented flanges in opposing contact elements may prevent the light engine from collapsing in effect of forces both up and down along axis 102.

Furthermore, the pivot 120 may be modified to include a locking system to provide added stability to the resilient hinge. For example, a light engine may include a latch that can slide laterally perpendicular to the z-axis between an open and a locked configuration as described next.

An example light engine 200 is shown in FIGs. 6A and 6B in which a latch includes a slider 241 and a retainer 243. In this example, the contact elements 233, 235 have flanges with L-shaped profiles. The contact element 233 in combination with the frame 240 form a hinge about a pivot 220. In this manner, the light engine 200 can freely hinge about the pivot 220 in the open configuration shown in FIG. 6A, and locked in place in the locked configuration shown in FIG. 6B when the slider 241 extends relative the retainer 243 across the pivot 220 to secure a planar alignment between the two pivoting portions of the light engine200. The latch in this example may be resiliently biased (not illustrated) into the locked configuration shown in FIG. 6B, via springs, notches and grooves or other elements.

Referring again to FIGs. 1 to 4, the light engine 100 resiliently abuts via contact element 135 the inside of the external heat sink when inserted into the aperture of the housing 105, and the contact element 133 will be pivoted into the noted plane of light engine 100 (in this example, parallel to the (x,y)-plane). In the assembled configuration, the contact elements 133 and 135 can establish an intimate thermal contact with the external heat sink (housing 105). In this example, heat dissipation is predominantly via contact element 135. Other implementations may be configured with different sized and/or shaped contact elements and different numbers of contact elements.

As noted above, FIG 4 shows a perspective cut-away schematic view of the example luminaire 101 during insertion of the light engine 100 into the housing 105. When the light engine 100 is inserted into the aperture of housing 105 with the contact element 133 facing up, the hinge (formed by the contact element 133 and the remainder of the frame 140) begins to flatten and the contact elements 133 and 135 will establish contact with opposite sides of the inside of the external heat sink 105. When properly sized relative to the housing 105, the resulting pressure can resiliently hold the light engine 100 in place. To lock the example light engine 100 in place, flanges of the contact elements 133 and 135 need to extend beyond certain distances from the plane of the frame 140, e.g., as shown in FIGs. 5A-5D. Other implementations may employ other locking mechanisms, for example spring-loaded mechanisms, extension screws and so forth as described herein. Heat conducting couplings can further be established by magnetic couplings between components made of suitable materials.

The luminaire 101 is configured to transfer a significant portion of the heat generated by the LEDs via heat conduction to the external heat sink/housing 105 from where it can be dissipated further via conduction and/or natural convection to the environment, as indicated by flow arrows in FIG. 1. Heat conduction provides significantly lower thermal resistance and better heat transport compared to convection via intermediary gases. Adequate metal contact elements with intimate thermal contact can effectively dissipate heat into the external heat sink/housing 105. In addition, thermal interface materials including gap pads, thermal greases or other thermal interface materials can be disposed between the contact element(s) and the heat sink 105 to improve contact for heat conduction.

Depending on the implementation, one or more contact elements can have a degree of rigidity/flexibility or even pliability that allows them to deform to certain degrees under typical installation conditions, for example to assume the shape of the inside of the external heat sink/housing 105 to facilitate large area thermal contact interfaces. For example, respective contact elements can be provided with flexible, resilient flanges that extend from the light engine 100 in azimuthal (about axis 102), polar (up/down axis 102) or both directions relative to axes of the light engine 100 and of the external heat sink 105. Such contact elements may be referred to as rigid or flexible contact elements, respectively.

Flanges may be integrally formed with the light engine or include spring leaves. In some implementations, the flanges are removably resiliently biased, or permanently attached, for example, screwed, riveted, glued, soldered, brazed, welded or otherwise operatively coupled with the light engine to ensure adequate heat transfer. Depending on the implementation, flanges may have uniform, tapered or even flared extensions. The contact elements can be configured to provide a degree of rigidity/flexibility that is adequate with that of the external heat sink/housing 105 to provide a reliable thermal and mechanical coupling in the assembled configuration. For this purpose resilient arc shaped flanges that extend annularly from a center portion of the flange outward toward tips of the arcs can have curvatures smaller than or equal to the curvature of the inside of the external heat sink 105 such that the flanges engage the inside of the external heat sink 105 beginning at the tips when the light engine is inserted into the aperture.