Headlamp module and headlamp assembly with internally reflecting translucent member

A headlamp module for a motor vehicle. The module includes a light source and a translucent member for internally reflecting the light rays so as to be directed. In one aspect of the invention, the light source is discretely positioned adjacent to a periphery defined by the exit surface so as to be directly hidden from view from the front of the vehicle. In another aspect, an outer surface of the light source is directly supported by the translucent member so that light rays emitted through an outer surface of the light source directly enter the translucent member.

BACKGROUND

1. Field of the Invention

The invention relates generally to a headlamp assembly and a headlamp module for use in a motor vehicle. More specifically, the invention relates to a headlamp module having an internally-reflecting trough for directing light rays in a forward direction and a headlamp assembly having a plurality of headlamp modules, at least one of which includes an internally-reflecting trough for directing light rays in a forward direction.

2. Related Technology

Conventional headlamp assemblies typically include one or more sets of headlamp modules cooperating with each other to provide illumination for a motor vehicle. For example, one set of headlamp modules may define a low beam, another set of headlamp modules may define a high beam, and another set of headlamp modules may define a turn signal.

Each of the headlamp modules typically includes a housing and a lens cooperating to define a cavity, a light element that is generally centrally located within the cavity, and a reflector positioned near a rear portion of the cavity to reflect light rays from the light element towards the front of the cavity and out through the lens. Often, the light element is a light emitting diode connected to the headlamp module by a support arm. Furthermore, the reflector is typically a component made of a generally reflective material, such as polished metal or highly-reflective plastic that covers all or most of the rear wall of the cavity.

Because the light element is positioned in a generally closed cavity, the housing and the components defining and providing electricity to the light element are potentially exposed to undesirable heat levels from light element. Therefore, this type of design typically requires temperature mitigating components, such as a heatsink supporting the light element with respect to the housing and cooling channels formed by the housing itself. Even if these structures are able to consistently prevent undesirably high heat levels, the temperature mitigating components generally increase the complexity and the part cost of this type of headlamp module.

Due to their highly reflective nature and centralized location, the light element, the components supporting the light element, and the reflector are all highly visible components. More specifically, these components are particularly visible when the light element is not emitting light, causing the unlit headlamp module to have a generally undesirable aesthetic appearance.

Another known type of headlamp module is an internal reflector module. In this design, a light source is spaced apart from the base of a translucent block for directing light rays into the body of the translucent block. More specifically, the light source is positioned along a central axis of the translucent block so that the light rays exit the light source, travel across an air gap, and then enter the translucent block. The light rays are then reflected internally by the inner surfaces of the translucent block in a desired direction. However, as with the above described design, the centralized location of the light source creates a generally aesthetically undesirable appearance. Furthermore, the air gap may cause undesirable light loss or an unsecured connection between the light source and the translucent block.

It is therefore desirous to provide a headlamp module having a decreased complexity and part cost and an aesthetically desirable appearance.

SUMMARY

In overcoming the limitations and drawbacks of the prior art, a headlamp module is provided, including a light source for emitting light rays and a translucent member for supporting the light source and directing the light rays in a forward direction. More specifically, the light element is positioned so that the light rays enter the translucent member and are internally reflected in a forward direction by a reflection surface. The light rays then pass through an exit surface of the translucent member as a light beam.

In one aspect of the present invention, the support portion is positioned with respect to the exit surface such that a projection of the support portion along a line parallel to the light ray axis is located adjacent to or outside of a periphery of the exit surface. Therefore, the light source is discretely positioned with respect to the exit surface so as to be substantially hidden to an observer examining the unlit headlamp module from the front of the vehicle.

In another aspect of the present invention, the translucent member includes top and bottom surfaces that each intersect respective portions of the exit surface and the support portion is defined by the top surface. More specifically, the top surface extends generally perpendicularly from a top portion of the exit surface and defines a relief for supporting the light element.

In another aspect, the bottom surface extends in a direction that is not perpendicular with the exit surface so that the light rays are focused into a beam exiting the exit surface. More specifically, the bottom surface generally defines a parabola and the light source is positioned adjacent to a focus thereof so that the light rays are vertically focused into a beam.

The headlamp module also includes first and second side surfaces that intersect: the top surface, the bottom surface, and the exit surface. The side surfaces each preferably include a tapered portion extending in a direction not parallel to the light ray axis so that the light rays are horizontally focused into a beam exiting the exit surface. The tapered portion may be generally linear or arcuate.

In another aspect of the present invention, the translucent member includes a reflective coating defining at least a portion of the reflection surface to prevent light rays from exiting the translucent member through surfaces other than the exit surface.

In yet another aspect, the headlamp module includes a plurality of light sources supported by a second support portion of the translucent member.

In another aspect of the present invention, the light source emits light rays through an outer surface and at least a portion of the outer surface is engaged by a support portion of the translucent member so that light rays emitted through the outer surface of the light source are able to immediately enter the translucent member. This configuration reduces light losses that may occur when the light rays from traveling through different mediums.

In one design, the light source is a light emitting diode and the outer surface is at least partially defined by a translucent protective coating. Additionally, the support portion preferably completely engages the outer surface of the translucent protective coating. Furthermore, the translucent protective coating is preferably connected to the support portion by a form-fitting engagement.

In another aspect of the present invention, a headlamp assembly for a motor vehicle includes a plurality of headlamp modules cooperating to provide illumination for the motor vehicle. In one design, at least one of the plurality of headlamp modules is a trough module cooperating with at least one other trough module to define a set of trough modules. The headlamp assembly may also include a set of projector modules cooperating with the set of trough modules to generate a low beam. The headlamp assembly may also include a high beam module configured to generate a high beam and a turn signal module configured to generate a light signal beam.

DETAILED DESCRIPTION

Referring now to the drawings,FIG. 1shows a headlamp assembly2installed in the front of a motor vehicle3, including a set of trough-type headlamp modules10and a set of projector-type headlamp modules5cooperating to generate a low beam; a high beam module6for generating a high beam; a set of turn signal modules7a,7bfor generating a turn signal beam; and a set of park light modules8for generating a parking light beam. The projector-type headlamp modules5, the high beam module6, the turn signal modules7a,7b,and the park light modules8shown inFIG. 1are each generally known in the prior art.

FIG. 2shows an enlarged view of the trough-type headlamp module10shown inFIG. 1. The trough-type headlamp module10includes a light source, such as a light emitting diode (LED)12, and a translucent member, such as a trough14, for directing light rays from the LED12in a forward direction. More specifically, the LED12is positioned near a rear portion15of the trough14so that light rays enter the trough14and are directed forwards through an exit surface16at a front portion17of the trough14to define a light beam for illuminating an area in front of the motor vehicle.

As shown inFIG. 3, the LED12includes a chip18for emitting light, a translucent protective coating20surrounding the chip18for protection thereof, and a substrate22supporting the chip18within the trough14and housing electrical components of the LED12. As is known in the art, to illuminate the LED12an electrical current is passed to the chip18via electrical wiring (not shown) and the movement of electrons across a pair of diodes (not shown) causes the LED12to emit light rays30. Alternatively, any other appropriate light source may be used with the trough-type headlamp module10, including but not limited to incandescent light bulbs or high intensity discharge lamp.

The trough14shown in the figures is a single, unitary solid body component defining a top surface32, a pair of side surfaces34,36, and a bottom surface38that each intersect the exit surface16along edges thereof. More specifically, the top surface32and the exit surface16are both generally planar surfaces positioned generally perpendicular to each other (seeFIG. 3). Furthermore, the side surfaces34,36and the bottom surface38each define generally arcuate surfaces for directing the light rays as desired, as will be discussed in further detail below. The side surfaces34,36are generally perpendicular to the exit surface16at the point of intersection, but taper inwardly along respective parabolic paths40,42from the front portion17to the back portion15of the trough14(seeFIG. 5). Similarly, the bottom surface38defines a parabolic path44tapered upwardly from the front portion17to the back portion15of the trough14(seeFIG. 3). As will be discussed in more detail below, the parabolic paths40,42,44of the side and bottom surfaces34,36,38cause light rays to be directed light towards the center of the beam pattern that exits through the exit surface16.

The LED12is supported by a support portion46of the trough14positioned with respect to the exit surface16such that a projection of the support portion46along a line60parallel to the light ray axis48, is located adjacent to or outside of a periphery62of the exit surface16, thereby substantially hiding the LED12to an observer examining the unlit trough-type headlamp module10from the front of the vehicle. This configuration is illustrated inFIGS. 2 and 4, where the support portion46is positioned in-line with the periphery62of the exit surface16.

The support portion46in the figures is a recess formed in the top surface32of the trough14so that the light rays entering the trough14are directed towards the bottom surface38(as best shown inFIG. 3). More specifically, the support portion46is located in the rear portion15of the trough14, adjacent to a focus56of the parabolic paths40,42,44of the side and bottom surfaces34,36,38.

The above-described positioning of the LED12with respect to the trough14offers many advantages that are discussed in more detail below. First of all, the positioning of the LED12adjacent to the focus56of the parabolic paths40,42,44causes the light rays that exit the LED to be focused into a beam that exits the exit surface16. Secondly, as mentioned above, the positioning of the LED12along the top surface32of the trough improves the aesthetic appearance by minimizing the perception of the LED12, of the trough-type headlamp module10for an observer viewing the module10from the front of the vehicle. Thirdly, the orientation of the LED12shining light rays in the downward direction minimizes glare to occupants of on-coming vehicles.

The support portion46shown in the figures conforms to the shape of the LED12to minimize or eliminate any air gaps between the LED outer surface and the trough14. The form-fitting configuration between the outer surface of the LED12and the trough14securely connects the components12,14to each other and reduces the likelihood of undesirable separation thereof. Furthermore, the form-fitting configuration reduces or prevents relative movement between the components12,14, thereby reducing premature part wear. The LED12may be coupled with the trough14by a form-fitting engagement or by another appropriate connection means, such as an adhesive or a mechanical fastener. However, direct contact between the LED chip18and the trough14may cause damage or premature wear to the LED12. Therefore, the translucent protective coating20surrounds the chip18to provide protection and to increase the product life of the LED12.

The elimination of air gaps between the LED outer surface and the trough14may also reduce light losses within the trough-type headlamp module10. It is a natural principle that light traveling between different mediums may undergo light losses due to reflection. Thus, it is generally desirable to minimize the number of different mediums that the light rays must travel through before exiting the trough-type headlamp module10. It is therefore more specifically desirable to minimize air gaps that the light rays must travel through.

As mentioned above, the light rays30entering the trough14are directed towards the bottom surface38and substantially internally reflected in a forward direction towards the exit surface16. More specifically, some of the light rays (the reflected rays30a) are reflected towards the exit surface16while the remaining light rays (the refracted rays30b) may exit the trough14through the bottom surface38.

As is a generally known natural principle, when a light ray intersects a boundary of a medium at a relatively large angle of incidence, a substantial percentage of the light ray will be reflected within the medium and the small, remaining percentage of the light ray will be refracted while exiting the medium through the boundary. Conversely, when a light ray intersects a boundary of a medium at a relatively small angle of incidence, a substantial percentage of the light ray will be refracted while exiting the medium through the boundary and the small, remaining percentage of the light ray will be reflected within the medium. Therefore, resultant light rays typically include both reflected components and refracted components. However, for illustrative purposes, resultant light rays are referenced by and depicted with their dominant components. As used herein, the term “reflected rays30a” refers to rays each have a higher percentage of light that is reflected towards the exit surface16than light that is refracted through the bottom surface38of the trough14. Similarly, as used herein, the term “refracted rays30b” refers to rays each have a higher percentage of light that is refracted as it exits the bottom surface38than light that is reflected towards the exit surface16.

The above principle is demonstrated with respect to the present invention inFIG. 3, where the reflected rays30aeach strike the bottom surface38at a relatively large angle of incidence50and the refracted rays30beach strike the bottom surface38at a relatively small angle of incidence50. The reflected rays30aare each substantially completely reflected towards the exit surface16whereas the refracted rays30bare each permitted to substantially completely exit the trough14through the bottom surface38. As a result of exiting through the bottom surface38, the refracted rays30bare not utilized for illuminating the area in front of the vehicle. Therefore, it is desirable to maximize the reflected rays30aand minimize the refracted rays30b,as will be discussed in more detail below with respect to further embodiments of the present invention.

As mentioned above, the bottom surface38of the trough14defines a parabolic path44. More specifically, the parabolic path44is configured such that the reflected rays30aare generally evenly spread in a vertical direction when shining through the exit surface16. The positioning of the LED12adjacent to the focus56of the parabolic path44of the bottom surface38further improves the concentration of the reflected rays30ain the vertical direction.

However, due to the light losses from the refracted rays30b,the light rays30only exit a lower portion54of the exit surface16, thereby only illuminating a lower portion of the trough-type headlamp module10. As used herein, the illuminated portion54is defined as the portion of the exit surface16that receives a substantial amount of light rays when the LED is illuminated. Similarly, a non-illuminated portion58is defined as the portion of the exit surface16that receives little or no light when the LED is illuminated. Although the non-illuminated portion58may receive trace amounts of light that are remnants of the refracted rays30b,this light is not necessarily sufficient enough to effectively illuminate an area in front of the trough-type headlamp module10.

The parabolic path44is also configured such that the rays30areflected by the bottom surface38are directed so as to be parallel with each other and to define a light beam extending generally along a light ray axis48. Although some of the reflected rays30amay extend in a direction not parallel to the axis48, the headlamp beam is substantially focused to extend along the axis48.

As mentioned above, the side surfaces34,36of the trough14also define parabolic paths40,42. More specifically, the parabolic paths40,42are configured such that the reflected rays30aare generally evenly spread in a horizontal direction when shining or passing through the exit surface16(as best shown inFIG. 5). The positioning of the LED12adjacent to the focus56of the parabolic paths40,42further improves the concentration of the reflected rays30ain the horizontal direction.

However and as shown inFIG. 5, the parabolic paths40,42are configured such that only some of the reflected rays30athat are reflected by the side surfaces34,36are directed so as to be parallel with each other and to define the headlamp beam extending along a light ray axis48. The remaining reflected rays30aare directed along paths not parallel with the light ray axis48so as to be dispersed across lateral areas in front of the vehicle. More specifically, while it is generally desirable for the headlamp beam to have a relatively focused spread in the vertical direction, it is generally desirable for the headlamp beam to have a wider range of lateral illumination so that the vehicle occupants are able to see a wider area in front of the vehicle. Comparing the parabolic paths40,42,44inFIGS. 3and %, the path44of the bottom surface38maintains a generally downward slope near the front portion17of the trough14, whereas the side surfaces34,36have paths40,42that are generally parallel with the beam axis48near the front portion17of the trough14.

The respective paths40,42,44of the trough14can be altered from those shown inFIGS. 2-5to produce a headlamp beam having particular characteristics. For example, the side paths may have different slopes and/or different shapes so that the trough-type headlamp module has a wider range of illumination on one side compared to the other side. This design may be particularly advantageous for the different characteristics desired from a driver-side trough-type headlamp module and a passenger-side trough-type headlamp module. For example, it may be desirable for the drivers-side trough-type headlamp module to have a wider range of illumination to the left and a trough-type passenger-side trough-type headlamp module to have a wider range of illumination to the right.

Furthermore, as discussed above, the location of the LED12along the top surface32of the trough14also improves the aesthetic appearance of the trough-type headlamp module10to an observer viewing the trough-type module10from the front of the vehicle. Because the LED12is positioned generally adjacent or in-line with the periphery62of the exit surface16rather than centrally with respect to of the exit surface16, an observer is less likely to see and notice the LED12through the exit surface16. Furthermore, because the upper portion of the exit surface16is the non-illuminated portion58, an opaque trim portion may be disposed over the non-illuminated portion58to further conceal the LED12.

The downward-facing orientation of the LED12generally minimizes glare from distracting the vehicle occupants. For example, the refracted rays30bexit the trough14in the downward direction.

The trough14is preferably formed of a generally transparent material having a relatively high luminous transmittance to minimize light losses within the trough. For example, the trough14is preferably made from one of the following materials: glass, polymethyl methacrylate (PMMA), polycarbonate resins, polystyrene resins, styrene-acrylonitrile (SAN) resins, cellulose acetate, or any other material having a relatively high light transmission percentage.

It may also be desirable for the trough14to be formed of an easily moldable material, such as resin, to simplify the manufacturing process and reduce manufacturing costs. Although it may be desirable for the resin to have a particular color so that the light beam is colored, the resin is preferably colorless or lightly tinted so as to further minimize light losses. Alternatively, the trough14may be substantially colorless with a tinted portion defining the exit surface16. In this design, it may be advantageous to form the trough of two, differently-colored sections that are connected with each other.

Referring toFIG. 6, an alternative trough-type headlamp module110is shown, having side surfaces134,136that each define a tapered portion180,182extending in a direction not parallel to the light ray axis148and a non-tapered portion181,183extending in a direction substantially parallel to the light ray axis148. The non-tapered portions181,183provide converging light rays similar to the design shown inFIG. 5, but the portions180,181,182,183are generally linear to simplify the manufacturing steps and to simplify the mounting components for the trough-type headlamp module110.

FIG. 7shows another alternative trough-type headlamp module210, including a plurality of LED's218a,218b,218c(three being illustrated) supported by the translucent member214. Due to the presence of multiple LED's218a,218b,218c,the trough-type headlamp module210can produce a headlamp beam generally having a higher light output.

FIG. 8shows yet another alternative trough-type headlamp module310, where the LED312itself is directional and has a limited spread to minimize the refraction rays that escape through the bottom surface338of the trough314. For example, the LED312is positioned such that its rearward-most directed light rays394strike the bottom surface338at an angle of incidence sufficiently large to reflect the light rays towards the exit surface316. Therefore, all, or substantially all, of the light rays emitted from the LED312are at least substantially reflected towards the exit surface316.

FIG. 9shows another alternative trough-type headlamp module410, where the translucent member414includes a reflective coating490covering at least a portion of the bottom surface438. The reflective coating490is a highly-reflective material, such as metal, so that the rearward-most directed light rays494are reflected towards the exit surface416rather than being lost through the bottom surface438, as is seen inFIG. 3.

Although the projector-type headlamp modules5, the high beam module6, the turn signal modules7a,7b,and the park light modules8shown inFIG. 1are each generally known in the prior art, in an alternative design the headlamp assembly2may utilize a plurality of trough-type light modules embodying the principles of the present invention in lieu of these modules5,6,7a,7b,8.