Vehicle light assembly including a diffuser surface structure

Details Vehicle light assembly including a diffuser surface structure Vehicle light assembly including a diffuser surface structure

1998-08-25

2002-03-05

Husar, Stephen (Department: 2875)

Illumination

Supported by vehicle structure

Light modifier

C362S331000, C362S334000, C362S509000, C362S521000, C362S541000

Reexamination Certificate

active

06352359

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to vehicle lights, and more particularly it relates to vehicle light assemblies that incorporate a diffuser surface structure on a surface of the assembly which homogenizes, shapes and directs light exiting the light assembly.
2. Description of the Related Art
It is well known that automobiles use many different interior and exterior lights and light assemblies for various purposes on the vehicle. Other vehicles such as trucks, boats, motorcycles, bicycles, load carriers, airplanes, construction equipment and essentially any other type of vehicle also utilize many different lights and light assemblies. Most light assemblies utilized on vehicles are crude from an optics standpoint and employ rudimentary designs and constructions for convenience and appearance purposes. These types of lights include vanity mirror lights, license plate lights, dome lights, map reading lights, flood lights, instrument panel lights, displays and instrumentation, as well as other types of convenience illumination systems for vehicles. In contrast, certain vehicle light assemblies including headlamps, turn signals, reflectors, brake lights and taillights are provided for safety purposes as well as for appearance. These more important types of lights employ slightly better technology in material and design but also employ only surprisingly crude optics in their design or construction primarily for aesthetic purposes. Very little thought is given to putting the light emanating from such light assemblies where it is most needed as to maximizing transmission efficiency of the assembly.
For example, the most important light utilized on nearly all vehicles is the headlight or forward illumination light so the operator can see ahead of the vehicle and so that others can see the vehicle as well. The taillights of vehicles are also important to make the rear of the vehicle visible in the dark to operators of other vehicles. Most of these types of lights employ a parabolic reflector surface disposed behind and partially surrounding a light source such as lamps or bulbs having a filament and LED's.
FIG. 1
illustrates a schematic of a typical light assembly such as a headlamp or a portion of a taillamp. The assembly
20
has a parabolic reflective surface
22
and a light source
24
spaced from the surface
22
. The lines “L” indicate the directionality of light emanating from the source
24
and the path of light reflected by the reflector surface
20
. As illustrated, the light generally passes from the source toward a transparent cover
26
or is reflected by the reflector forward toward the cover in a generally predetermined direction. However, in reality this type of light source has two significant problems which are typically not adequately addressed.
First, the light source
24
has a filament (not shown) that typically does not distribute light evenly. For example, incandescent or halogen bulbs are typically utilized for interior and exterior vehicle lighting systems. Each of these types of bulbs includes a filament housed within an enclosed chamber of the bulb. This chamber is somewhat pressurized where the amount of pressure depends on the type bulb utilized. Halogen bulbs are at a much higher pressure than a standard incandescent bulb. Failure of the bulb usually results from failure of the filament. The filament reacts with gases in the chamber or simply glows by application of energy to the filament to illuminate the bulb. These filaments do not evenly produce light and generate what are known as high intensity regions where more light is directed and low intensity regions where less light is directed. When utilizing a reflection type lighting system, the high and low intensity regions are simply reflected back out from the reflection and remain in the projected light from the assembly. These high intensity and low intensity regions make it difficult for an operator to see objects that the light is intended to illuminate. Such objects may be a map inside a car or may be more importantly a road surface or cars ahead of the vehicle making lane changes or braking. If the light assembly is not a reflection type but merely the type where a bulb or LED directs light from a housing through a lens or cover that spreads the, light the high intensity and low intensity regions are again merely projected as is from the lens.
Secondly, a lot of the light energy or photons are wasted in all different types of automotive or vehicle light assemblies. This is based upon the fact that much of the light leaving a bulb or other light source within the assembly is directed immediately outward from the light source and not directed toward a particular target by either the parabolic reflector surface or by the light source or the lens itself. Any light escaping the light assembly that is not directed toward a particular target is simply wasted. In automotive lighting systems, much of the light from any source is propagated away from the intended direction and wasted. This wasted and misdirected light can cause difficulty in the form of glare for individuals in the general area of the particular vehicle and the light source. “Masking” of a light is sometimes resorted to in order to keep light from emanating in particular directions where it is not desired such as lane changes, lane illumination or braking. This further wastes light energy and adds further complexity to light assemblies.
Lens covers
26
are sometimes utilized in vehicle light assemblies which have certain lens design or shape characteristics formed therein. These lens characteristics are typically in the form of Fresnel optics, elongate cylindrical lenses, and pillow optics. Each of these types of lenses is intended to spread or otherwise disperse light exiting a light assembly. For example,
FIGS. 2 and 3
illustrate very simple schematics of a light assembly utilizing cylindrical dispersion elements
30
(
FIG. 2
) and Fresnel optics
32
(FIG.
3
). These are commonly utilized for vehicle taillamp constructions wherein a bulb
34
is held in a fairly deep and narrow housing
36
illuminating outward through an opening
38
. Most taillight assemblies have a number of separate compartments, each one having its own light source and separate or at least distinct cover or lens design. A lens cover or cover section
40
is dispersed over the opening
38
in the housing
36
. A Fresnel structure
32
or cylindrical dispersion element structure
30
is incorporated in the lens cover
40
to provide some spread of the light as it exits the housing. Other surface structures such as a prismatic or pillow optic structure are also commonly used. Each of these particular designs is fairly inefficient and does nothing to solve either of the above described problems. In fact, many vehicle light assembly designs are such that, though a lot of light would be lost without such a lens cover, more light may be wasted by utilizing the Fresnel optics or the cylindrical lens construction. This is because the light exiting the housing is further spread by the lens designs. Even more light is wasted where the lens cover is designed to mask light to prevent it from emanating in an undesired direction.
These same problems exist and in fact are enhanced by the more rudimentary designs of the bulbs, housings, reflector surfaces (if present) and lens cover designs for other types of less important vehicle lights such as interior dome lights, map lights, general illumination lights, dash lights, exterior hood and trunk lights, and other vehicle marker lights. Much light is spread to areas beyond a target thus wasting a lot of the light. Additionally, high and low intensity regions are also present for these much simpler designs. The severity of the high and low intensity regions depends upon the type of lens cover placed over the light.
Another element mentioned above and used in the art of vehicle light assembly design is known as “pillow optics,” such as are illustrated in
FIGS.

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