Fluorescent tube cabin lighting

The present invention relates to a lighting device for lighting the cabin of a motor vehicle, the device comprising an elongate light source disposed inside a housing. According to the invention, the lighting device further comprises: two windows transparent to the light flux emitted by the source, the windows being spaced apart from each other and comprising a top window through which light radiation is emitted in a generally horizontal direction, and a bottom window through which light radiation is emitted generally downwards; a first directional light reflector disposed between two respective first edges of the windows; and a second directional light reflector disposed between the two respective other edges of the windows; the directional light reflectors having shapes that combine to guide the light flux emitted by the source towards the transparent windows.

The present invention relates to a novel device for lighting the cabin of a 
motor vehicle. 
BACKGROUND OF THE INVENTION 
At present, in the state of the art, there exists a cabin lighting device 
used in particular as a ceiling light or as a courtesy light and that 
comprises a light source disposed inside a housing that includes a 
transparent window through which the light source emits a beam of light 
into the cabin. 
The main drawback of such a device is that in order to provide proper 
lighting of the inside of the cabin, the device emits a light beam towards 
the passengers and dazzles them. 
OBJECT AND SUMMARY OF THE INVENTION 
The invention seeks to provide a novel device for lighting the cabin of a 
motor vehicle, the device comprising an elongate light source disposed 
inside a housing, and enabling interior lighting of the cabin to be 
obtained by projecting a beam of light towards the ceiling and towards the 
space in which passengers are active, but without dazzling them. 
More particularly, according to the invention, the housing of the lighting 
device comprises: 
two windows transparent to the light flux emitted by the source, the 
windows being spaced apart from each other and comprising a top window 
through which light radiation is emitted in a generally horizontal 
direction, and a bottom window through which light radiation is emitted 
generally downwards; 
first directional light flux recovery means disposed between two respective 
first edges of said windows; and 
second directional light flux recovery means disposed between the two 
respective other edges of said windows; 
said directional light flux recovery means having shapes that combine to 
guide the light flux emitted by the source towards said transparent 
windows. 
In a particularly advantageous embodiment of the invention, the elongate 
light source is a fluorescent tube.

As a preliminary point, it should be observed that portions that are 
identical or similar from one figure to another are given the same 
reference symbols and are not described each time. 
MORE DETAILED DESCRIPTION 
FIGS. 1 and 2 show an embodiment of a lighting device for lighting a motor 
vehicle cabin 20, the device comprising a fluorescent tube 11 disposed 
inside a housing 10. The housing 10 is pivotally mounted in bearings 41 of 
a support 40 designed to be mounted on a portion of the vehicle. 
The housing 10 includes first directional light flux recovery means 12 
disposed between the fluorescent tube 11 and the "activity space" of the 
cabin 20 in which passengers 30 are to be found. In this case, the first 
light flux recover means 12 is constituted by a segmented cylindrical 
mirror facing the fluorescent tube 11 and generally coaxial with said 
tube, masking it in part. In addition, the housing 10 has two windows 13 
and 14 that are transparent to the light flux, namely a top window 13 and 
a bottom window 14 that are spaced apart from each other on opposite sides 
of the first light flux recovery means 12. Each of the windows 13 and 14 
extends from one of the edges of the first light flux recovery means 12, 
and the two windows extend substantially perpendicularly relative to each 
other. As can be seen in FIG. 2, the transparent windows 13 and 14 include 
regularly spaced-apart stripes 17 on their inside surfaces facing towards 
the fluorescent tube 11. These stripes 17 serve to process the light flux 
passing through the windows, in particular by altering the direction 
thereof. The stripes promote optimization of lighting inside the cabin. It 
should be observed that in other embodiments (not shown) the stripes could 
be replaced by other light-processing means such as prisms, striped 
prisms, toruses, or beads. 
The housing 10 also includes second light flux recovery means comprising 
two associated reflectors 15 and 16. In the embodiment shown, each of 
these two reflectors 15 and 16 is parabolic and extends parallel to the 
axis of the segmented cylindrical reflector. The focal line of the 
parabolic reflector is close to the light source, and together the 
reflectors extend between two respective edges 13a and 14a of the 
transparent windows 13 and 14 so as to face the first light flux recovery 
means 12. The two reflectors 15 and 16 are connected to each other along 
an edge in a central portion that is close to the fluorescent tube 11. 
In operation, the first directional light flux recovery means 12 is 
designed to reflect back into the housing 10, the light flux that is 
emitted by the fluorescent tube 11 towards passengers 30 occupying the 
activity space of the cabin 20. The reflectors 15 and 16 are suitable for 
reflecting the light flux emitted by the fluorescent tube 11 and also the 
light flux reflected by the first flux recovery means 12 so as to direct 
the light towards the transparent windows 13 and 14. On passing through 
said windows 13 and 14, the light flux is modified by the stripes disposed 
on the inside surfaces of said windows. Thus, said device serves to form 
two light beams propagating in two essentially perpendicular directions. A 
first beam is emitted in an essentially horizontal direction towards the 
ceiling 21 of the cabin 20. A second beam is directed essentially 
vertically into the activity space of the cabin 20 without dazzling the 
passengers 30. 
FIG. 3 shows another embodiment of the lighting device in which the first 
and second directional light flux recovery means 12, 15, and 16 of the 
housing comprise cylindrical reflecting surfaces having profiles 
determined by computation using a computer. The reflecting surfaces of 
said recovery means combine so as to direct the light flux emitted by the 
fluorescent tube 11 towards the top and bottom transparent windows 13 and 
14 which are disposed substantially parallel to each other in this case. 
In this typical case, the transparent windows 13 and 14 through which the 
light flux is emitted have inside and outside faces that are smooth or 
slightly diffusing. 
The light radiation emitted through the top window 13 is directed 
substantially horizontally while the light radiation emitted through the 
bottom window 14 propagates in an essentially vertical downward direction. 
In a variant embodiment shown in FIG. 4, the transparent windows 13 and 14 
include regularly spaced apart stripes 17 on their inside surfaces facing 
the fluorescent tube 11. Here again, it should be observed that in other 
embodiments, not shown, the stripes could be placed on the outside faces 
of the windows, and they could be replaced by other light-processing means 
such as prisms, toruses, or beads. 
Naturally, the present invention is not limited in any way to the 
embodiments shown and described, and the person skilled in the art will be 
able to apply variations thereto within the spirit of the invention.