Patent Application
20120049733
This disclosure relates to a lighting module, and more particularly to a replaceable light emitting diode (LED) module with integrated optics and thermal management features. This disclosure finds particular application in the automotive industry where optical precision is demanded, although selected attributes and features may be used in related environments and applications where similar issues may be encountered.
Generally, LED based lighting assemblies used for forward lighting in automotive applications include an LED light source that cooperates with a separate optics assembly for handling light output from the light source. Light output is less optimal as a result of separately assembling the light source with the separate optics assembly.
Further, LED lighting assemblies incorporated into forward lighting applications are not easily replaceable. Consequently, although LED light sources are efficient and have an extended operating life, if a problem should occur or the light source fails, then it is necessary to remove the entire light source. Moreover, no provision is made for precisely aligning the new LED light source with the associated optics.
Another important aspect of using high efficiency LED light sources is the need to address thermal issues. Specifically, LED light sources operate at elevated temperatures and effectively conveying away heat maintains the benefits of the high efficiency and extended life of this type of light source.
Accordingly, a need exists to provide an LED light source that is a replaceable module and is operatively integrated with the optical system. Further, such an assembly must adequately manage thermal concerns and be easily and accurately mounted to the associated automotive vehicle.
A replaceable light assembly for an automotive vehicle is disclosed. The assembly includes a housing having at least one light emitting diode (LED) assembly and a lens received over and secured to the LED assembly. An electrical circuit received in the housing conditions voltage from the automotive vehicle for operating the LED assembly. A base advantageously conducts heat from the LED assembly, while a positioning mechanism optically aligns and positions the housing relative to the associated automotive vehicle.
In an exemplary embodiment, an enlarged thermal mass conveys heat from the LED assembly.
In one embodiment, the base includes first and second members having cooperating convex and concave surfaces, respectively, for orienting the LED assembly relative to the lens, and the convex and concave surfaces have different curvatures.
A primary benefit provided by the new assembly is the ability to replace both the light source and the optics as a unit.
Another advantage relates to obtaining precise alignment between the LED light source and the optical arrangement.
Still another benefit is the ability to accurately position the replaceable LED module relative to the associated vehicle.
Yet another advantage relates to improving overall lamp life and efficiencies by incorporating thermal management features into the replaceable module design.
An additional benefit is the incorporation of electronics, therefore the module can be directly driven from the car board voltage system without further electronic drive.
Still other benefits and advantages may become more apparent to one skilled in the art upon reading the following detailed description.
Shown in
More particularly, the module 100 includes a light source which, in this arrangement, is at least one light emitting diode 102 and preferably multiple LEDs as may be required for a particular application such as forward lighting arrangements. In the automotive industry, such forward lighting arrangements include using the module as a daytime running light (DRL) or other applications such as a position light or index light. In this embodiment, each LED 102 includes an associated respective printed circuit board (PCB) 104. PCB 104 is provided for the LED only. Once mounted on the associated printed circuit board 104, the light source 102 is, in turn, mounted on a thermally conductive block such as metal block 106 which in the present arrangement has a significant disk-like dimension to provide a desired thermal mass for conveying heat from the LED 102 and PCB 104. Since LED-based lamps typically operate at a temperature below 200 degrees C. or more preferably in some instances at 100 degrees C. or even lower, the heat transfer pathway is important. Convection and conduction are the predominant forms of heat transfer that can be enhanced by use of a heat sink. The heat sink, or metal block in this instance, is a component providing a large surface area for radiating and convecting heat away from the LED devices. A relatively massive metal element having a large engineered surface area efficiently conducts heat from the LED devices and the large area of the mass provides efficient heat egress by radiation and convection. In this manner, heat conducted by the LEDs is advantageously transferred to the metal block 106 located at the rear of the module 100. In addition, the heat is conveyed to a heat conducting foil or layer 108 disposed at an opposite end of the block 106 from the light source. Heat is thereby effectively conveyed from the LEDs 102 through the metal block 106 to the heat conducting foil 108 and thus to the surrounding ambient environment for effective thermal management of the lighting module 100. In addition to the heat convective function of the heat conducting foil 108, the conducting foil 108 may be connected to further heat sinks (not shown) operatively associated with the headlamp. For example, additional heat sinks may be needed if further light sources are used in order to reduce the operational temperature of the headlamp. Preferably, the printed circuit board 104 that carries the LEDs 102 is connected to the metal block 106 with a heat conductive adhesive to further enhance the thermal conveying properties of the lighting module 100.
Housing 120 is shown in the preferred arrangement as a generally annular structure having an opening 122 formed in a first or rear wall 124. The opening 122 is dimensioned to receive a nose portion 126 of the metal block 106 therethrough. In addition, small dimensional openings 128 are provided in the wall 124 and cooperate with spacers 130 for receipt of fasteners such as threaded screws 132. The fasteners extend through a mounting plate 140, particularly openings 142 in the mounting plate, which is supported by the spacers 130 at a predetermined dimension from the back wall 124 (
As is also evident in
Peripherally spaced locating flanges or tabs 164 are shown extending radially outward from a rim 166 that is provided about the perimeter of the housing 120. The three or more spaced tabs 164 provide for connection with an associated fixture. Curved protrusions 168 extend axially outward from the rim 166 (see
Electrical connection in the embodiment of
In addition, rather than having integrated flanges or tabs 164 associated with a rim 166 as employed in the earlier embodiment, alignment is provided by a separate plate 294 that has three or more lobes 296 (
In addition, and as best illustrated in
Setting the direction of the light distribution is also simplified by using the convex and concave surfaces 284, 286 that have slightly different curvatures along their contacting surfaces and subsequently fixing the position of these two components when aligned in the desired manner. Likewise, electrical connection is achieved in an efficient manner with the spring contact 270 provided on the generally cylindrical surface of the housing. Although only two terminals or contacts 270 are shown, it will be understood by one skilled in the art that additional sockets or terminals may be provided, for example for use with dimming options, where the module can fulfill the requirements of different applications.
The LED-based assemblies provide for effective forward lighting and are advantageously replaceable. This eliminates problems associated with replacing just the light source without the optics so that precision alignment and desired light distribution are achieved. In addition, the replaceable module addresses the complicated thermal management concerns by providing a sufficient thermal mass that conducts the heat to the rear of the module. Also the electronic drive circuit is integrated into the assembly and permits the light source to be driven by the voltage provided by the automotive vehicle.
The disclosure has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the disclosure be construed as including all such modifications and alterations.
