Illumination – Light source and modifier – Including reflector
Utility Patent
1999-02-23
2001-01-02
O'Shea, Sandra (Department: 2875)
Illumination
Light source and modifier
Including reflector
C362S551000, C362S560000, C362S576000, C362S293000, C362S583000, C362S268000, C359S833000, C359S834000, C359S868000, C359S884000, C359S819000
Utility Patent
active
06168294
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates broadly to outdoor lighting systems and, more particularly, to a signal light for incorporation into traffic areas, especially airport runways and taxiways.
Signal lights of this type are provided essentially for incorporation as ground-level units mounted within the pavement and are used especially as guide elements in airports.
Such lights are also adaptable for street traffic conditions. U.S. Pat. No. 5,438,495 to Ahlen et al discloses a signal light which has a deviating prism as optics, which acts to deviate the light beam relative to a horizontal plane. It should be noted at the outset that the term “optics” as used herein shall mean any light manipulating mechanism, assembly, arrangement or means. Nevertheless, in most applications, it is of great importance for the signal light to have a flat structure, so that it projects only slightly above the traffic surface. This requirement is fulfilled by the signal light according to Ahlen et al only to a limited extent and problems may occur during practice when driving over the device or when the traffic area has to be cleaned or cleared.
In order to avoid these problems, the light exit openings are frequently recessed, at least partly. However, the corresponding recesses may become contaminated with water, dirt, or other contaminants so that discharge and cleaning cycles must be provided. Otherwise, the light intensity is expected to markedly decrease, thereby effecting the safety associated with the traffic facility.
Accordingly there exists a need for a signal light for incorporation into the pavement of runways and other traffic areas that provides consistent lighting, yet remains essentially flush with the pavement surface.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a compact signal light that is essentially flush with the outer surface of its support base, whether the base is an airport runway or taxiway, a street or highway, or any other traffic area.
To this end, a signal light for mounting within a support base to be substantially flush with respect to an outer surface of the support base comprises a housing, a light source arranged in said housing, a light processing assembly having an entry area for collecting light from said light source, an exit area for emitting light, and a curved mirror for reflecting and processing light between said entry and exit area, wherein said light deflecting optics is designed for emitting a light bundle, which light bundle is substantially non-divergent in at least one direction. The curved mirror allows the light processing assembly to process light efficiently and in a compact manner.
Preferably, the entry area is larger than the exit area, wherein said light has higher intensity at the exit area than at the entry area, and wherein said light at the entry area is substantially non-divergent and non-convergent, i.e. “parallel”. In such an arrangement, the light processing assembly increases the light intensity and is therefore able to emit it from a very small area, which allows to reduce the size of the exit aperture. This permits a very flat construction.
In a preferred embodiment, the entry area comprises convergent input optics for directing light towards said mirror in convergent manner. This convergence can be compensated by the curvature of the mirror, e.g. by curving the mirror in such a way that it emits the light in non-convergent and non-divergent manner. “Non-convergent and non-divergent” in this sense relates to the convergence/divergence of the light bundle in at least one direction, preferably the vertical direction, while the light may e.g. be divergent horizontally. In the direction where the light is neither convergent nor divergent, it forms a light field with only small aperture, e.g. in the order of a few degrees.
Preferably, said light processing assembly comprises a transparent optical body, wherein said entry area is formed by an entry surface of said body and wherein said exit area is formed by an exit surface of said body. The mirror can also be formed by a surface of the body.
The entry surface is preferably curved outwards, e.g. by having generally cylindric shape. As a result of this, light collection can be achieved in at least one direction. However, Fresnel lenses, holograms, curved mirrors or index-gradient optics may be used for this purpose.
The exit surface is preferably perpendicular to the exiting light. As a result of this, the exit surface will be smaller, which reduces the danger of soiling, damage or both.
In a preferred embodiment, the light source comprises a curved array of light emitting diodes generating light convergent onto the curved mirror. This obviates the need for providing strongly convergent input optics. The light from the diodes can be processed in a transparent optical body having a flat entry surface section forming said entry area, a flat exit surface section forming said exit area, and a curved mirror surface section forming said curved mirror.
In another aspect of the invention, the signal light for mounting within a support base to be substantially flush with respect to an outer surface of the support base comprises a housing, a light source arranged in said housing, and a light processing assembly for generating an emerging light bundle, which light bundle is substantially non-divergent in at least one direction, said light processing assembly comprising a first optical body having an entry surface for collecting light from said light source in convergent manner and an exit surface for emitting light from said first body in substantially non-convergent manner, wherein said entry surface and said exit surface each form one of a curved lens and a Fresnel lens.
In yet another aspect of the invention, the signal light for mounting within a support base to be substantially flush with respect to an outer surface of the support base comprises a housing, a light source arranged in said housing and a transparent optical body having an entry surface section for receiving light from said light source, an exit surface section for emitting a light bundle that is substantially non-divergent and non-convergent in at least one direction, and a curved mirror surface section for reflecting light between said entry and exit area, wherein in said at least one direction said light is impinging in convergent manner onto said curved mirror surface section and is being reflected therefrom in substantially non-divergent and non-convergent manner.
Preferably, the entry area includes a filter formed by one of a dichroic mirror and colored glass.
By the above, the present invention provides a signal light for mounting in a traffic surface that provides sufficient and consistent ground level lighting and remains essentially flush with the pavement.
REFERENCES:
patent: 3250907 (1966-05-01), Keck et al.
patent: 4354221 (1982-10-01), Hoffman
patent: 4408266 (1983-10-01), Sclippa
patent: 4860182 (1989-08-01), Vadseth
patent: 4914544 (1990-04-01), Dahlberg
patent: 4924364 (1990-05-01), Pannier
patent: 5335151 (1994-08-01), Dahlberg
patent: 5414603 (1995-05-01), Conway
patent: 5556189 (1996-09-01), Wallis
patent: 1497360 (1969-06-01), None
patent: 0022106 (1981-01-01), None
patent: 942296 (1963-11-01), None
Brand Andreas
Erni Ernst R.
DelGizzi Ronald E.
Ernst Erni
McGuire, Woods, Battle & Boothe, LLP
O'Shea Sandra
LandOfFree
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