Illumination – Plural light sources – With modifier
Reexamination Certificate
2002-06-06
2004-09-07
Cariaso, Alan (Department: 2875)
Illumination
Plural light sources
With modifier
C362S470000, C362S517000, C362S544000, C362S241000
Reexamination Certificate
active
06786618
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a light for an aircraft with a housing, comprising a light source and a reflector forming a bundle of light of the light emitted by the light source for generating a predetermined light distribution, and with a translucent cover for closing the housing.
2. Description of the Background Art
It is common to equip lights with incandescent lamps and a reflector to generate, as a position light, for example, a desired luminous intensity distribution (e.g., German Patent 41 17 289). In aircraft, it is known that for lights arranged on exposed positions of the aircraft, e.g., at the free ends of the wing or in a rear portion of the craft, different luminous intensity distributions in vertical and horizontal directions are predetermined. From the advertising documents of the company Hella KG Hueck & Co. “HELLA Aircraft Equipment”, a light (No. 2LA 001 625-xx) is known which satisfies a predetermined horizontal luminous intensity distribution in a range between +/−70°. The light comprises a housing wherein as a light source, an incandescent lamp is arranged coaxially with the housing. The incandescent lamp is arranged in a rotationally symmetrically configured reflector reflecting the light emitted by the incandescent lamp according to the predetermined light distribution. A front edge of the housing serves as a boundary edge for the emitted light bundle. A disadvantage of the known light is that the luminous intensity of the incandescent lamp has to be designed for being relatively high to satisfy the requirements as to the predetermined luminous intensity distribution. As a consequence, the minimum luminous intensity in some parts of the predetermined solid angle range of light radiation has to be exceeded by far so that the luminous intensity in other parts of the solid angle range of light radiation is barely above the minimum luminous intensity valid for these parts.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a light for an aircraft in such a manner that it is ensured to achieve a predetermined luminous intensity distribution with an increased efficiency.
To solve this object, the present invention provides a light, particularly a position light, for an aircraft, preferably for being mounted to the rear end of an aircraft, such as, e.g., an airplane, which is provided with a luminous device for emitting light, a reflector arrangement, and a housing comprising a receiving room for the luminous device and the reflector arrangement covered by a transparent cover, which are configured such that light, with a minimum intensity required along a preferential axis, emerges from the housing.
According to the invention, this light is characterized in that the luminous device includes a first and a second light source which are substantially identical and respectively emit light within a light radiation solid angle with a central axis, the two light sources are arranged symmetrically to the preferential axis and the central axes of the light radiation solid angle is inclined so as to face each other. The reflector arrangement includes a first and a second reflection surface allocated to the first and second light source, respectively, the reflection surfaces also being symmetrically arranged to the preferential axis and respectively provided with a light propagation limiting edge for limiting the light propagation range, within which light emitted directly by the respectively allocated light source emerges from the receiving room of the housing. The first reflection surface is arranged opposite to the first light source and the second reflection surface is arranged opposite to the second light source. The light propagation limiting edge of the first reflection surface faces away from the second light source and the light propagation limiting edge of the second reflection surface faces away from the first light source. The two reflection surfaces are oriented and/or configured such that light emitted by the one light source is reflected by the reflection surface allocated thereto past the light propagation limiting edge of the other reflection surface to increase the luminous intensity within the light propagation range of the other light source near the partial range defined by the light propagation limiting edge of the one reflection surface.
In the light according to the invention, the use of appropriately arranged reflection surfaces (as is indicated above) achieves that the requirements, particularly with respect to the light/dark border of light distribution functions, can be satisfied while using as few light sources as possible. This is particularly possible when LED elements or LED modules are used as light sources. The advantage of LED elements compared with conventional incandescent lamps (with spiral-wound filament or configured as flashtube) is that LED elements have a substantially longer service life. Moreover, LED elements are substantially less sensitive to interferences. Moreover, LED elements can be operated in a substantially smaller and lower voltage range than conventional incandescent lamps. Finally, the power consumption of LED elements is substantially lower than that of incandescent lamps. All this leads to advantages in technical and particularly also in economical regard, therefore, the aircraft industry and aviation companies are increasingly interested in the use of LED technique in the exterior lighting area of aircraft.
It has to be pointed out in this context, however, that the invention is not limited to LED elements as light sources but that conventional incandescent lamps can also be used as light sources or luminous device.
A certain disadvantage of LED elements is only their limited radiation angle range of from 120° to 180° (depending on the type). Therefore, it is required that the legal or international requirements in aviation as to the horizontal and vertical luminous intensity distributions of position lights on airplanes are satisfied in spite of this relatively limited solid angle radiation range by appropriately arranged reflection surfaces.
In a further embodiment of the invention, the reflector arrangement includes a third and a fourth reflection surface which are allocated to the first and second light source, respectively, and are also arranged symmetrically to the preferential axis and between the first and the second reflection surface when seen in a top view of the cover in the direction of the preferential axis and reflect the light emitted by the respectively allocated light source substantially in the direction of the preferential axis.
Suitably, the reflector arrangement has a fifth and a sixth reflection surface also arranged symmetrically to the preferential axis and offset by 90° with respect to the first and the second reflection surface, the fifth and the sixth reflection surface reflecting the light emitted by both light sources within a first solid angle range adjacent to the preferential axis. Suitably, the fifth and sixth reflection surfaces interconnect the first and second reflection surfaces.
In further embodiment of the invention, it is further provided that the reflector arrangement includes four seventh reflection surfaces which are diametrically opposed to each other in pairs and are arranged symmetrically to the preferential axis in pairs, that two seventh reflection surfaces are allocated to one light source, respectively, and that the four seventh reflection surfaces reflect light of the light sources respectively allocated thereto within a second solid angle range spaced from the preferential axis. Particularly, the first solid angle range is located between the preferential axis and the second solid angle range.
Particularly, the third and fourth reflection surfaces as well as the four seventh reflection surfaces are configured as parts of the surface of a common first reflector body, which, in top view of the cover of the housing, viewed in the direction of the preferential
Ganzer Bernd
Lueder Sascha
Schulz Rico
Cariaso Alan
Goodrich Hella Aerospace Lighting Systems GmbH
Lee Guiyoung
LandOfFree
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