Illumination – Light source and modifier – Including selected wavelength modifier
Patent
1995-04-21
1996-12-17
Yeung, James C.
Illumination
Light source and modifier
Including selected wavelength modifier
362 80, 362331, 362333, F21Q 100
Patent
active
055845703
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The present invention is concerned with a signal lamp, in particular, for use with automotive vehicles, comprising a casing, a light source arranged within the casing, a reflector for the parallel orientation of the light from the light source, a closure plate, an optical plate provided between the light source and the closure plate, and at least one colour filter disposed in the path of rays, with the optical plate, on the side thereof facing the light source, being provided with convex areas and, in particular, on the side thereof facing away from the light source with concave areas between which are arranged light-impermeable areas.
A so designed signal lamp is taught by DE 85 33 666 U1 in which the light from the light source is parallelized by the reflector and is directed toward the optical plate. The optical plate, at the same time, is in the form of a colour filter, imparting to the light emitted by the light source the required signal colour. Moreover, light-impermeable areas are provided on the side of the optical plate facing away from the light source, which areas convey to the signal lamp, with the light source turned off, a substantially uniform and attractive outward appearance. The light beams from the light source, through the optical plate, are so directed past the light-impermeable areas that the whole of the light entering the optical plate on the one side thereof exits on the other side thereof, leaving the signal lamp through the closure plate. With the light source turned off, a viewer through the closure plate which, as a rule, is transparent, only perceives the light-impermeable areas which are, for example, of black colour, thereby largely preventing a direct view of the colour filter.
A so designed signal lamp involves the disadvantage that the light distribution on the closure plate is not homogeneous, with light accumulations, such as light spots or light bars and the like, being likely to occur.
It is, therefore, the object of the invention to provide a signal lamp of the afore-mentioned type insuring a more homogeneous light distribution.
This problem, in the practice of the invention, is solved in that the side of the closure plate facing the light source is provided with concave recesses.
The design of the closure plate as suggested by the invention involves the advantage that the focal point is outside the lamp and that the black light-impermeable areas do not become clearly manifest from the optical plate. When viewing the signal lamp of the invention, no discrete black areas behind the closure plate, for example, parallel strips interrupted by the intervals of the coloured optical plate, can be seen any longer. When viewing the signal lamp according to the invention merely a dark face of a substantially homogeneous outward appearance is perceivable behind the closure plate.
In another embodiment the convex and concave areas and recesses are provided in series arrangement in the optical light path, thereby causing the beams passing through the individual convex areas of the optical plate to be optimally guided such that, on the one hand, the light-impermeable areas are not affected by the beam focusing while, on the other hand, the focused beam of light diverges again on the closure plate, thereby obtaining a homogenous light distribution externally of the closure plate.
The focal points of the concave areas and of the concave recesses, preferably, lie within a plane parallel to the parallelized light. The so defined arrangement of the optical system insures a precise ray pattern which can be adapted to any desired ambient conditions, such as an inclined assembly of the signal lamps into an automotive vehicle, by a suitable selection of the lenses, at the same time maintaining a homogenous distribution of light.
Preferably, the optical plate and the closure plate are arranged in parallel, in particular, at an inclination to the horizontal or the parallelized light, i.e. at an angle other than 90.degree.. In this special form of embodiment the fact can be take
REFERENCES:
patent: 4241388 (1980-12-01), Green
patent: 4383290 (1983-05-01), Binder et al.
patent: 4656567 (1987-04-01), Morris
International Search Report for Application PCT/EP93/02480 filed 14 Sep. 1993.
Binder Peter
Feger Rolf
Grynaeus Peter
Holzmacher Gunther
ITT Automotive Europe GmbH
Lewis J. Gordon
Raab Sara Sachie
Twomey Thomas N.
Yeung James C.
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