Luminaire for creating a primary beam and a secondary beam

The luminaire for providing a primary (10) and a secondary light beam (14) comprises reflector means (9) and a lamp holder (7) within a housing (1) having a window (2) through which the primary beam passes. Remote from the window (2), the reflector means are provided with an opening (11) for a secondary beam (14). A side wall (3) of the housing (1) has a window through which the secondary beam (14) is reflected to the outside by a reflector (15). The window (13) is provided with a refractor (12) to spread the secondary beam (14). The luminaire has a color filter (11) in the path of the secondary beam and provides an even appearance of a panel illuminated by that beam.

The invention relates to a luminaire for creating a primary beam and a 
secondary beam, comprising: 
a housing having an emission window for a primary beam and side walls 
transverse thereto; 
a lampholder in the housing for accommodating an electric lamp alongside 
the emission window; 
concave reflector means for throwing light generated by an accommodated 
lamp through the emission window to the exterior in a primary beam, which 
reflector means have an opening remote from the emission window; 
light-distributing means near a window for a secondary beam in a side wall 
of the housing; and 
a reflector in the housing for reflecting light passing through the opening 
in the reflector means towards the window in a side wall. 
BACKGROUND OF THE INVENTION 
Such a luminaire is known from British Patent Application GB-1 408 955. 
The known luminaire is particularly suitable for use with low-pressure 
mercury fluorescent lamps. The luminaire in a horizontal arrangement 
radiates both a primary beam in downward direction and a secondary beam in 
lateral direction. 
The secondary beam may illuminate an external or internal wall of a 
building or a panel. It is possible for such a panel, for example, to 
receive so much light in a region lying closest to the luminaire that its 
appearance considerably deviates from that of regions lying further away. 
More particularly, the region gives the impression of being lighter in 
colour and may have a shiny center. This is a disadvantage, since the 
panel is rendered unattractive by this and the attention is drawn away 
from the panel as an entity. 
SUMMARY OF THE INVENTION 
The invention has for its object to provide a luminaire of the kind 
described in the opening paragraph which facilitates inter alia a more 
uniform appearance of an item illuminated by the secondary beam. 
According to the invention, this object is achieved in that the luminaire 
comprises a colour filter for the light of the secondary beam. 
It is counteracted by means of the colour filter that so much light, for 
example white light, is radiated from the lamp accommodated in the 
luminaire onto a location of the irradiated object situated centrally in 
the beam that the reflection spectrum of the object in this central 
location is different from the spectrum elsewhere, owing to the fact that 
the object is no longer capable of sufficiently absorbing colours which 
are complementary to its own colour. This is prevented by the use of a 
colour filter which has a transmission spectrum corresponding to the 
colour of the object, i.e. its reflection spectrum. It is noted in this 
connection that the use of a colour filter need not adversely affect the 
illumination effect of the secondary beam of the luminaire because the 
light to be absorbed by the filter would not contribute to a useful 
illumination of the object: i.e. to showing the object in the same way as 
it would look under daylight. 
Since a light source has a greater brightness in proportion, the danger of 
local over-illumination of an object is greater. Nevertheless, a light 
source of high brightness is favourable since such a light source often 
converts a high power into light in a small volume, with a high luminous 
efficacy. Owing to its small volume and its high luminous flux, a 
high-pressure discharge lamp, for example a high-pressure mercury lamp 
with metal halide additives, or particularly a high-pressure sodium lamp 
emitting golden-yellow or white light, is particularly suitable for 
forming together with reflector means a primary beam which irradiates a 
wide surface area, for example a floor surface or a road surface. 
Especially in those cases there is a major risk of the secondary beam 
locally over-illuminating an object. Such high-pressure discharge lamps 
often have Edison lamp caps, for example E-40 lamp caps. The luminaire 
then has an Edison lampholder, for example, an E-40. 
In a favourable embodiment, the luminaire has the colour filter in a 
location where the area of the secondary beam is small, for example, in 
the opening in the reflector means. A comparatively small filter can then 
suffice. In addition, the secondary beam may be optimally defined in this 
way. 
Preferably, a profiled glass plate is used in the window, for example, with 
prismatic or concave semi-cylindrical ridges at the entrance side thereof, 
for example transverse to the emission window, with the object of 
spreading the secondary beam substantially parallel to the emission 
window. For a high and narrow object, the ridges may extend parallel to 
the emission window. If it is desirable to irradiate a wider area of the 
object by means of the secondary beam, for example, an area whose extent 
corresponds to the extent of the ground surface irradiated by the primary 
beam, the window in the side wall may extend to the adjoining side walls. 
The uniformity of the illumination of an object by the secondary beam, in a 
direction parallel to the emission window, may be improved by kinking the 
reflector backwards. Thereby, the reflector may e.g. have a kink in a 
plane through the lampholder. 
In a favourable embodiment, the luminaire radiates a secondary beam in two 
opposite directions away from one another since opposite a window a second 
window is present in a second side wall. 
It is favourable to give the reflector a bent shape. Bends parallel to the 
emission window spread the secondary beam in a direction transverse to the 
emission window, so that an object of a given height can be evenly 
illuminated. The reflector may be so designed that substantially all light 
from the secondary beam is reflected by the reflector. 
In a special embodiment, the emission window is closed off by a glass plate 
and the luminaire comprises louvres for restricting the emission of light 
of the primary beam at small angles to the glass plate. It can also be 
prevented in this way that light of the primary beam and light of the 
secondary beam become mixed. 
It is favourable for the reflector means to have the greatest spreading 
effect in a plane transverse to a plane in which the reflector has its 
greatest spreading effect.

DESCRIPTION OF THE INVENTION 
In the Figures, the luminaire for creating a primary beam and a secondary 
beam comprises a housing 1 with an emission window 2 for a primary beam 
and side walls 3-6 transverse thereto. A lampholder 7, such as an E-40 
lampholder in FIG. 1, is present in the housing for accommodating an 
electric lamp 8 alongside the emission window. The lamp drawn is a 
high-pressure sodium lamp which has a power rating of 250 W at a supply 
source of at least 200 V, radiating golden-yellow light. The lamp has a 
tubular, transparent lamp vessel in order to allow the generated light to 
emanate without being obstructed. 
Reflector means 9 reflects light 10 of the primary beam generated by the 
lamp 8 through the emission window 2 to the exterior. In addition, 
non-reflected light 10' also issues to the exterior. The reflector member 
9 has an opening 11 remote from the emission window 2. 
Light-distributing means, such as a profiled glass plate 12, for refracting 
light are present at a window 13 for a secondary beam 14 in a side wall 3. 
A reflector 15 is positioned in the housing for reflecting light 14, which 
passes the reflector member 9 through an opening 11, towards the window 13 
in the side wall so as to form a secondary beam. 
The luminaire has a colour filter 16 for the light of the secondary beam 
14. The filter 16 is situated in the opening 11 in the reflector means 9. 
A profiled glass plate 12 is present in the window 13, which plate spreads 
the light 14 of the second beam substantially parallel to the emission 
window 2. The window 13 extends between the opposing side walls 4, 6. 
Opposite the window 13, there is a similar window 13' in a second side wall 
5 with a profiled glass plate 12'. A reflector 15' reflects the filtered 
light of the secondary beam through the glass plate 12' and window 13' to 
the exterior, so that the luminaire shown radiates secondary beams in 
opposite directions. In the luminaire drawn, a second opening 11' and a 
second colour filter 16' are present for the window 13'. The reflector 15 
and the reflector 15' are bent substantially parallel to the emission 
window 2 in order to spread the secondary beam in the plane of the 
drawing. 
The emission window 2 is closed by a glass plate 17, louvres 18 being 
present on the glass plate. 
The reflector means 9 have their greatest spreading effect in planes 
perpendicular to the insertion direction of the lampholder 7 owing to its 
strongly bent shape, stepwise in the Figures, in the planes. The reflector 
15 on the other hand has its greatest spreading effect exactly in a plane 
through the insertion direction of the lampholder owing to its shape which 
is bent in a direction transverse to the above directions, stepwise in the 
Figures. 
The luminaire yields an even illumination of a ground surface with the 
primary beam and provides a uniform appearance of objects illuminated by 
the secondary beams, such as, for example, facades or panels mounted 
thereto. 
In FIG. 3 all parts are shown as if they were transparent. Except for the 
reflectors 25, 25' all parts have the same reference numeral as 
corresponding parts in the preceding Figs. The reflectors 25 and 25' are 
each kinked backwards to have a kink 26 and 26' respectively in a plane 
through the lampholder 7. The reflecting surfaces 25a and 25b of reflector 
25 are under an angle of more than 180.degree. to each other. Thereby they 
throw a larger portion of the light reflected into the direction indicated 
by arrows A and B respectively than without kink 26 being present.