CLEARANCE AND SIDE MARKER LAMP
BACKGROUND OF THE INVENTION
This invention relates generally to lamps for use with 5 motor vehicles, and more particularly to vehicle lamps having an array of light emitting diodes (LEDs) to provide both clearance and side marker functions.
The Society of Automotive Engineers (SAE), in SAE standard J592 JUN92, defines a clearance lamp as a lamp 10 mounted on a vehicle to provide light to the front or rear to indicate the overall width and height of the vehicle. A side marker lamp is defined as a lamp mounted on a vehicle to provide light to the side to indicate the overall length of the vehicle. Finally, a combination clearance and side marker 15 lamp, designated by the code "PC", is defined as a lamp simultaneously fulfilling the requirements of both clearance and side marker lamps. Typically, clearance, side marker lamps and PC lamps used on automobiles and truck/trailer combinations use standard high-intensity incandescent bulbs 20 as a light source with an optical lens in front of the light source to provide a desired photometric pattern. The lens usually provides an important second function of protecting the light source from dirt, moisture and other foreign matter. Incandescent light sources, however, have a relatively short 25 life and may further be somewhat delicate in that excessive handling may result in failure due to filament breakage.
LEDs are useful in vehicle lamps such as for combination brake, turn and tail lamps, and for clearance or side marker lamps. An advantage of using LEDs is that they have an 30 operating life of up to 100,000 hours before they begin to degrade.
Ordinarily, LEDs are not used in PC lamps due to the difficulty in designing lens optics to spread the light, emitted by an LED in a narrow cone pattern, into an arc pattern of 35 up to 180 degrees. Moreover, providing a PC lamp with LEDs would require multiple LEDs in order to satisfy the Federal Motor Vehicle Safety Standard (FMVSS) 108 lighting requirements. Using multiple LEDs in a single lamp housing thus further creates heat dissipation concerns since 40 it is known that high LED junction temperatures can significantly reduce LED light output. What is therefore needed is a PC lamp assembly that uses a robust light source having a long lifetime, and that sufficiently dissipates heat so as not to degrade the light source. 45
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, a clearance/side marker lamp for a motor vehicle comprises a 50 housing, a first plurality of light emitting diodes arranged within the housing and collectively operable to emit light in a first direction, a second plurality of light emitting diodes arranged within the housing and collectively operable to emit light in a second direction and a third plurality of light 55 emitting diodes arranged within the housing and collectively operable to emit light in a third direction. The second and third directions are each arranged at an acute angle relative to the first direction, and the third direction is arranged at an obtuse angle relative to the second direction. The first, go second and third directions are further arranged in a common plane such that the light emitting diodes emit light in an arc pattern within the common plane.
In accordance with another aspect of the present invention, a clearance/side marker lamp for a motor vehicle 65 comprises a first circuit board having a first mounting surface for mounting at least one light emitting diode
thereto, and a plurality of secondary circuit boards each having a second mounting surface for mounting at least one light emitting diode thereto. Each of the secondary circuit boards is rigidly attached to the first circuit board such that the second mounting surfaces are directed at a predetermined acute angle away from the first mounting surface. A housing is further included for receiving the circuit board assembly therein and has a first surface for mounting the first circuit board thereto. The light emitting diodes are mounted to each of the circuit boards such that light emitted therefrom has a beam axis directed perpendicularly away from the corresponding mounting surfaces.
In accordance with a further aspect of the present invention, a clearance/side marker lamp for a motor vehicle comprises a housing having a front portion, a rear portion and a body disposed therebetween, a plurality of light emitting diodes arranged within the housing wherein the plurality of light emitting diodes are operable to emit light toward the front and rear portions, and away from the body, and a lens mounted to the housing in front of the light emitting diodes. The lens has means for spreading the light emitted by the light emitting diodes through a range of approximately 180 degrees from the front portion to the rear portion.
One object of the present invention is to provide a combination clearance and side marker lamp having light emitting diodes as light sources in a single housing.
Another object of the present invention is to provide a combination clearance and side marker lamp having light emitting diodes mounted to a plurality of circuit boards disposed at multiple angles within a housing.
A further aspect of the present invention is to provide a combination clearance and side marker lamp having light emitting diodes as light sources wherein a lens is provided to spread light emitted from the diodes in an arc spanning approximately 180 degrees.
These and other objects of the present invention will become more apparent from the following description of the preferred embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an assembly drawing of a clearance and side marker lamp in accordance with the present invention.
FIG. 2 is a perspective view of the circuit board and housing portions of the embodiment shown in FIG. 1.
FIG. 3 is a side elevational view of the circuit board and light source portion of the embodiment shown in FIG. 1.
FIG. 4 is an elevational view of an alternate light source for use with the embodiment shown in FIG. 1.
FIG. 5 is a cross-sectional view of the lens portion, shown in FIG. 1, along the sections lines 5—5.
FIG. 6 is a magnified view of the area A shown in FIG. 5.
FIG. 7 is a cross-sectional view of the lens portion, shown in FIG. 1, along the sections lines 7—7.
FIG. 8 is a magnified view of region B shown in FIG. 7.
FIG. 9 is a diagrammatic illustration of a truck-trailer combination showing a typical application of the clearance and side marker lamp embodiment of FIG. 1 in use therewith.
FIG. 10 is an assembly drawing of a clearance and side marker lamp in accordance with an alternate embodiment of the present invention.
DESCRIPTION OF THE PREFERRED
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to