Patent Application
20140268853
The present invention generally relates to signal assemblies that provide uniform illumination through light source location and spacing control, and more particularly to vehicular signal lamps with LED light sources located and spaced to provide uniform illumination.
Various LED signal assemblies are employed today with great practical effect. In the automotive industry, many vehicles utilize LED-based lighting assemblies, taking advantage of their much lower energy usage as compared to other light sources, including halogen- and incandescent-based systems. One problem associated with LEDs is that they tend to produce highly directional light. The light emanating from conventional LED-based vehicular lighting assemblies often has low uniformity and hot spots. Consequently, conventional LED-based lighting assemblies have a significant drawback when used in vehicle applications requiring high uniformity—i.e., signal lamps.
Accordingly, there is a need for signal assemblies, and LED-based vehicular signal assemblies, that exhibit a high degree of light uniformity while operating at high efficiencies.
One aspect of the present invention is to provide a signal assembly that includes a chamber defined by isotropically luminant back and side surfaces, and a front surface having a lens and a diffuser. The signal assembly also includes LED light sources having a beam angle ≧70° coupled to the back surface. The back and front surfaces are separated by a depth, and each source is located at a spacing from the other sources≦the depth divided by a predetermined factor.
Another aspect of the present invention is to provide a signal assembly that includes a chamber defined by isotropically luminant back and side surfaces, and a front surface having a lens and a diffuser. The signal assembly also includes LED light sources having a beam angle ≧100° coupled to the back surface. The back and front surfaces are separated by a depth, and each source is located at a spacing from the other sources≦the depth divided by a predetermined factor.
A further aspect of the present invention is to provide a signal assembly that includes a chamber defined by isotropically luminant top, bottom, and back surfaces, a depth, a front surface having a lens aperture and a diffuser. The signal assembly further includes bi-directional LED light sources coupled to the back surface, each having beam angles≧light exit angles defined by the sources and the aperture. Each source is located at a spacing from the other sources≦the depth divided by a predetermined factor.
These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings.
In the drawings:
For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in
LED signal assemblies are employed today with great practical effect. In the automotive industry, many vehicles now utilize LED-based lighting assemblies. Much of the engineering work in connection with these vehicle lighting assemblies emphasizes a reduction in their overall dimensions, particularly depth, for space saving and fuel efficiency benefits (i.e., “low-profile” lighting assemblies). Further, these LED-based vehicular assemblies rely on multiple LED light sources, each inherently producing high light intensity with small beam angles. Accordingly, many LED-based lighting assemblies, including “low-profile” assemblies, produce “hot spots” of discrete light associated with each LED light source.
What has not been previously understood is how to configure and design such LED-based lighting assemblies to produce highly uniform light for vehicular signal applications, including applications requiring “low profile” assemblies. Highly uniform light is particularly beneficial for vehicular signal applications (e.g., brake lights, taillights, daytime running lights (DRLs), turn signals, reverse lamps, etc.). Further, vehicular lighting assemblies that produce highly uniform light are desirable for many vehicle owners for aesthetic reasons. Referring to
Signal assembly 20 includes a chamber 16 defined by isotropically luminant back and side surfaces 18, and a front surface having a lens aperture 8 and a diffuser 6. As depicted in exemplary fashion in
As shown, each of the LED light sources 10 is coupled to the back surface of the chamber 16, within cavity 16a, and produces light rays with a beam angle 4 (see
Light rays within cavity 16a that have emanated directly from sources 10, and those that have been reflected off of isotropically luminant surfaces 18, pass through diffuser 6. Diffuser 6 then causes the light rays originating from sources 10, typically LED-based sources, to further scatter and spread. This has the effect of improving the uniformity of the light rays exiting diffuser 6 and, ultimately, aperture 8. Diffuser 6 may be fabricated from known diffuser technologies (e.g., Light Shaping Diffuser® films provided by Luminit, LLC). Diffuser 6 can possess a divergence angle ≧15°, ≧20°, or even ≧30°.
The back and front surfaces of chamber 16 are separated by a depth 14, as further depicted in
Signal assembly 20 is particularly effective at producing highly uniform light that emanates from lens aperture 8 through the control of depth 14 relative to spacing 12. In essence, signal assembly 20 allows light emanating from each of multiple LED sources 10 to blend before exiting the cavity 16a via diffuser 6 and aperture 8. By increasing the depth 14 of the chamber 16 relative to the spacing 12, the relationship D/d≧A is satisfied. As the light sources 10 are situated further back within cavity 16a, a greater percentage of the incident light from these sources 10 can blend before exiting the cavity 16a and chamber 16. Referring to
Referring to
Each of the LED light sources 30 is coupled to the back surface of the chamber 36, within cavity 36a, and produces light rays with a beam angle 24a and 24b (see
Light rays within cavity 36a that have emanated directly from sources 30, and those that have been reflected off of isotropically luminant surfaces 38, pass through diffuser 26. Diffuser 26 then causes the light rays originating from sources 30, typically LED-based sources, to further scatter and spread. This improves the uniformity of the light rays exiting diffuser 26 and, ultimately, aperture 28. Diffuser 26 may also be fabricated from known diffuser technologies (e.g., Light Shaping Diffuser® films provided by Luminit, LLC), and can possess a divergence angle ≧15°, ≧20°, or even ≧30°.
As shown in
Signal assembly 40 is particularly effective at producing highly uniform light that emanates from a relatively narrow lens aperture 28 through the control of depth 34 relative to spacing 32. In essence, signal assembly 40 allows light emanating from each of multiple LED sources 30 to blend before exiting the cavity 36a via diffuser 26 and aperture 28. By increasing the depth 34 of the chamber 36 relative to the spacing 32, the relationship D/d≧A is satisfied. As the light sources 30 are situated further back within cavity 36a, a greater percentage of the incident light from these sources 30 can blend before exiting the cavity 36a and chamber 36. Referring to
It should be understood that the foregoing relationships of spacing 12, 32; depth 14, 34 and the predetermined factor A for signal assemblies 20 and 40 are exemplary. Larger D/d ratios (i.e., the depth 14, 34 is increasingly larger relative to the spacing 12, 32) need less scattering through diffuser 16, 36 and/or smaller LED beam angles 4, 24a, 24b to achieve the desired light uniformity. This translates to the use of a diffuser 6, 26 with a smaller divergence angle, e.g., ≧20° and/or an LED source 10, 30 with a smaller beam angle 4, 24a, 24b, e.g., ≧70°. On the other hand, when the D/d ratio is reduced, more light scattering is necessary through diffuser 6, 26 and/or higher beam angles 4, 24a, 24b are needed to achieve the desired light uniformity. As such, a diffuser 6, 26 with a larger divergence angle, e.g., ≧30°, and/or an LED-based light source 10, 30 with a larger beam angle 4, 24a, 24b, e.g., ≧100°, can be acceptable to incorporate within the signal assembly 20 and 40 configurations when D/d ratios are reduced (e.g., “low profile” signal assembly 20, 40 designs).
It should also be understood that the foregoing relationships can be “local” in the sense that the aperture 8, 28; depth 14, 34 and spacing 12, 32 need not be constant throughout the entire signal assemblies 20 and 40. For example, aperture 8, 28 may take on a variety of shapes, including circular, elliptical, rectangular and square shapes, each with varying degrees of curvature. As such, the aperture 8, 28 need not have a uniform shape. Similarly, the light sources 10, 30 arranged on the back side of chamber 16, 36 within cavity 16a, 36a need not be arranged in a line as depicted in exemplary fashion in
Signal assembles 20 and 40 may be flexibly employed in a variety of lighting technologies and applications, including vehicular signal applications. As such, the chamber 16, 36 of signal assemblies 20, 40, including aperture 8, 28 and diffuser 6, 26, may be shaped and dimensioned for use in DRL, turn signal, brake signal, tail light signal, reverse signal, and other vehicular signal applications. It should be understood that lens aperture 8, 28 and/or diffuser 6, 26 may include various color filters associated with the appropriate vehicular signal application. For example, aperture 8, 28 may include a red filter for variants of signal assembly 20, 40 to be employed in brake and tail lamp signal applications. Further, sources 10, 30 employed in signal assembly 20, 40 may be powered and sized based on the type of application, applicable regulations and other engineering constraints.
As shown in
Tail-light assembly 60 is arranged in a tail-light configuration with a chamber 56, cavity 56a and lens aperture 48 all dimensioned to conform to the rear of a vehicle. The chamber 56 is defined by isotropically luminant back and side surfaces 58, and a front surface having a lens aperture 48 and a diffuser 46.
As shown in
Light rays within cavity 56a that have emanated directly from sources 50, and those that have been reflected off of isotropically luminant surfaces 58, pass through diffuser 46. Diffuser 46 then causes the light rays originating from sources 50, typically LED-based sources, to further scatter, spread and blend. This has the effect of improving the uniformity of the light rays exiting diffuser 46 and, ultimately, aperture 48. Diffuser 46 can possess a divergence angle ≧15°, ≧20°, or even ≧30°.
The back and front surfaces of chamber 56 are separated by a depth 54, as further depicted in
As further shown by
Certain recitations contained herein refer to a component being “configured” or “adapted to” function in a particular way. In this respect, such a component is “configured” or “adapted to” embody a particular property, or function in a particular manner, where such recitations are structural recitations as opposed to recitations of intended use. More specifically, the references herein to the manner in which a component is “configured” or “adapted to” denotes an existing physical condition of the component and, as such, is to be taken as a definite recitation of the structural characteristics of the component.
Variations and modifications can be made to the aforementioned structure without departing from the concepts of the present invention. Further, such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.
