Illumination – Supported by vehicle structure – Light modifier
Reexamination Certificate
1999-07-21
2001-06-26
O'Shea, Sandra (Department: 2875)
Illumination
Supported by vehicle structure
Light modifier
C362S223000, C362S297000, C362S346000
Reexamination Certificate
active
06250786
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to motor vehicle headlights in general, and more particularly to such incorporating tubular light sources, especially gas discharge tubes.
2. Description of the Related Art
There are already known various constructions of motor vehicle headlights, among them such which incorporate tubular light sources, especially gas discharge tubes. Each of these headlights or headlight assemblies includes a reflector that is positioned along the tubular light source and incompletely embraces the same to leave an open end toward and through which it reflects the light emanating from the light source and impinging on the reflector. A light-guiding disk or plate spans the open end of the reflector and directs the light emanating from the light source and reflected by the reflector to a predetermined area situated in front of the vehicle on which the headlight assembly is mounted when in use.
In this scenario, it is known to configure the reflector as a cross-sectionally parabolic cylinder constituted by two parabolic branches or regions that are displaced parallel to the longitudinal direction of the reflector. Such cross-sectionally parabolic cylindrical reflectors reflect the light rays emanating from the tubular light source onto them in directions parallel to respective optical planes of such reflectors. Cross-sectionally parabolic cylindrical reflectors of this kind have a multitude of optical axes that are situated next to each other and extend in parallelism with one another, lying in or actually defining the optical plane. In addition, each of such reflectors has a multitude of foci that are disposed next to each other on a focal axis of the reflector.
However, such a cross-sectionally parabolic cylindrical reflector does not embrace or envelop the tubular source to any great extent in that it exhibits a relatively small embracing angle in comparison to the overall size of the reflector. As a consequence of this relatively small extent of the embracing angle, the proportion of the light emitted by the light source that impinges upon and is thus captured by the reflector and reflected by the same is also relatively small. For this reason, these conventional headlight or similar illuminating units with cross-sectionally parabolic cylindrical configurations are capable of issuing only light beams with a relatively low light intensity and/or density and are not suited for applications in which high light density is called for (for instance, in use as a brake light).
In an attempt to solve this relatively low illumination capability problem, it has been proposed in the past to provide the headlight assemblies with larger-dimensioned reflectors of the conventional type. When this measure is resorted to, it is namely possible to increase the aforementioned embracing angle and thus to capture and reflect a greater proportion of the light rays emanating from the light source. Yet, experience has shown that this approach may lead to other problems, especially those stemming from the amount of space occupied on the motor vehicle by such headlight assemblies, especially since, driven by aerodynamic and/or aesthetic considerations, less and less space is being made available on motor vehicles for the accommodation of headlight assemblies. The end result is that a conflict exists between the quest for the highest possible illumination light intensity, on the one hand, and for the smallest possible headlight dimensions, on the other hand.
OBJECTS OF THE INVENTION
Accordingly, it is a general object of the present invention to avoid the disadvantages of the prior art.
More particularly, it is an object of the present invention to provide a motor vehicle headlight assembly that does not possess the drawbacks of the known equipment of this type.
Still another object of the present invention is to devise a headlight assembly of the type here under consideration which issues a highly concentrated light beam onto the area ahead of the vehicle that is to be illuminated.
It is yet another object of the present invention to design the above assembly in such a manner as to keep its overall dimensions to a minimum without adversely affecting its illumination capacity.
A concomitant object of the present invention is so to construct the assembly of the above type as to be relatively simple in construction, inexpensive to manufacture, easy to use, and yet reliable in operation.
SUMMARY OF THE INVENTION
In keeping with the above objects and others which will become apparent hereafter, one feature of the present invention resides in a motor vehicle headlight assembly that includes a reflector having at least in general the configuration of a flattened cross-sectionally parabolic cylinder, a light source including an elongated gas discharge tube extending within the reflector along a common focal line, and an at least translucent light-guiding plate spanning the open end of the reflector. According to the invention, the reflector consists at least in part of two opposing regions at least one of which is inclined by a predetermined angle about the focal line with respect to the position it would have assumed in a true cross-sectionally parabolic cylinder. As a result of this configuration, the light that is issued by the light source onto the reflector is reflected by the latter into the open end, where the light-guiding plate directs the light passing through it onto an illumination area situated at a predetermined distance in front of the motor vehicle on which the headlight assembly is mounted when in use.
A particular advantage of the motor vehicle headlight assembly of the present invention as described so far is that its reflector has much smaller dimensions than those used in conventional assemblies of this kind, and yet exhibits the same embracing angle relative to the light source and, consequently, captures and reflects the same amount of light issued by the latter, as conventional reflectors that follow a truly parabolic course and thus have much larger overall dimensions. Or, viewed from a different vantage point, in the headlight assembly constructed in accordance with the present invention so that its reflector has the aforementioned flattened parabolic cross-sectional configuration, the reflector envelops the light source with a much greater angle than that used in a conventional headlight assembly that conforms to a true parabola in cross section.
It is particularly advantageous when, in accordance with the present invention, not just one but each of the above-mentioned regions of the reflector is inclined about the focal line. The angle of such inclination may be different for each of the reflector regions in question, but it may also be the same for both of them. An advantage of this approach is that, by judiciously selecting the angle(s) of the reflector region(s), it is possible to selectively fashion and/or determine the headlight light distribution into the space in the front of the motor vehicle. The angle by which the cross-sectionally parabolic region or regions are inclined (i.e. angularly displaced from the position(s) it (they) would have assumed had they both followed the parabolic course) has a magnitude of at most 45°. As a general rule, the greater this angle of inclination of the parabolic regions or branches, the greater is the embracing angle by which they envelop the light source and, consequently, also the amount of light emanating from the light source that these regions of the reflector constructed in accordance with the present invention capture and reflect. However, commencing at the angle of inclination of the parabolic reflector regions amounting to about 45°, there is not obtained any further increase in the amount of light captured and reflected by the reflector; rather, light rays emitted by the light source are totally reflected by parabolically shaped reflector regions angularly displaced from their true-parabola positions by more than about 45°.
In accordance with a further advantageou
Bahnmueller Gerd
Boebel Doris
Schuster Kurt
DelGizzi Ronald E.
O'Shea Sandra
Robert & Bosch GmbH
Striker Michael J.
LandOfFree
Headlight assembly with angularly displaced reflector regions does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Headlight assembly with angularly displaced reflector regions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Headlight assembly with angularly displaced reflector regions will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2444236