Illumination – Supported by vehicle structure – Light modifier
Reexamination Certificate
2000-01-19
2001-10-09
O'Shea, Sandra (Department: 2875)
Illumination
Supported by vehicle structure
Light modifier
C362S555000, C362S545000, C362S498000, C362S494000
Reexamination Certificate
active
06299334
ABSTRACT:
BACKGROUND OF THE INVENTION.
The invention concerns a vehicle lamp of the kind set forth in the preamble of the claims.
A specific configuration of such a vehicle lamp is known for example from EP 0 858 932 A2. That involves a flashing lamp which is incorporated into the housing of an external rear view mirror. Such a situation of use involves so little space behind the light exit cover or lens that it is not possible to arrange a light source there and to so surround it with a reflector that the light given off by the light source is substantially uniformly irradiated through the entire area of the light exit lens.
Therefore, disposed in the region of the one narrow end edge is a light source which generally comprises at least one light emitting diode but generally a plurality of light emitting diodes, the light of which is coupled into the light exit lens in such a way that a part of that lens is passed by total reflection to the other narrow end edge at which it issues and is irradiated into a given solid angle. A further part of the coupled-in light is given off in approximately uniformly distributed fashion by way of the outside surface of the light exit lens.
So that a side flashing lamp of that kind can be perceived not just from the front, that is to say viewing in a direction in opposite relationship to the direction of travel of the vehicle, but also from the side, the light exit lens is of an elongate shape and, as viewed from above, it is curved in such a way that the vertical planes in which the narrow end edges thereof extend include an angle of almost 90° with each other.
If the attempt is made to impart a greater curvature to the light exit lens of such a vehicle lamp also in the transverse direction, it is found that for example in the case of a side flashing lamp of the above-indicated kind, the light output in a horizontal direction falls sharply. In order to avoid that, it is thus possible to use light exit lenses which are only slightly curved or flat in the transverse direction, as are known from above-mentioned EP 0 858 932 A2, or it is possible to use more and/or stronger lamp members, for example light emitting diodes, in order to compensate for the light losses which occur due to the irradiation effect in the transverse direction.
SUMMARY OF THE INVENTION
The former approach limits the configurational options for vehicle lamps of that kind to a substantial degree, while the second approach means that the structure of such a lamp becomes more complicated and the manufacturing costs thereof rise.
In comparison the object of the invention is so to develop a vehicle lamp of the kind set forth in the opening part of this specification that, even with a light exit lens geometry which is heavily curved in the transverse direction, distribution of the light in the light guide with minimum losses is possible so that, unlike known designs, the number of light emitting diodes can be reduced and/or lower-strength light emitting diodes can be used.
That object is attained by the features of the invention recited in the claims.
Those measures are based on the realization that, when the light exit lens is also more greatly curved in the transverse direction, a part of the light issuing through the outside surface thereof is given off in the direction of the tangent which can be applied to the curved surface at the relevant point of the outside surface of the light exit lens transversely to the longitudinal direction. In the case of a side flashing lamp in which the longitudinal direction of the light exit lens extends substantially horizontally, this means that, depending on respective curvature involved, a considerable part of the issuing light is irradiated vertically upwardly or downwardly and thus does not contribute to perceptibility of the side flashing lamp in a horizontal direction.
The fact that, in accordance with the invention, the inside of the light exit lens is not in the form of a uniform surface but is provided with an optical structure which focuses the light issuing through the outside in a preferential direction, achieves a light output which is markedly increased in the desired preferential direction, without increasing the amount of space required and without increasing the manufacturing costs, so that the number and/or strength of the light sources can be reduced. At the same time the light exit lens can be curved in all directions substantially more greatly than hitherto so that it can be adapted to the shape or external contour of any parts of the vehicle. That means that substantially fewer limits are imposed on the configurational design options, than is the case in the state of the art.
In a particularly preferred embodiment the vehicle lamp is a side flashing lamp which can be fitted in particular into the housing of a motor vehicle external mirror. The optically effective structure at the inside of the light exit lens is in that case such that, with the light exit lens extending substantially horizontally, the light is focused in a vertical direction so that it issues substantially in a horizontal direction.
The optically effective structure provided on the inside of the light exit lens is preferably formed by a series of strip-shaped regions which are arranged in mutually juxtaposed relationship in the transverse direction and which extend in mutually parallel relationship in the longitudinal direction of the exit lens; in that arrangement each of those regions is arranged tilted in non-parallel relationship with respect to the region of the outside surface, which is immediately opposite thereto.
If the curvature of the light exit lens is irregular in the transverse direction, the strip-shaped regions are tilted to different degrees in dependence on the magnitude of that curvature.
These and further advantageous configurations of the vehicle lamp according to the invention are set forth in the appendant claims.
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patent: 4646208 (1987-02-01), Hayashi et al.
patent: 4929866 (1990-05-01), Murata et al.
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patent: 5303130 (1994-04-01), Wei et al.
patent: 5938320 (1999-08-01), Crandall
patent: 6086229 (2000-07-01), Pastrick
Bräutigam Markus
Quent Peer
Schwanz Martina
Fer Fahrzeugelektrik GmbH
Negron Ismael
O'Shea Sandra
Sughrue Mion Zinn Macpeak & Seas, PLLC
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