Title of Invention

FRESNEL LENS SPOTLIGHT WITH COUPLED VARIATION OF THE SPACING OF LIGHTING ELEMENTS

Abstract In order to provide a Fresnel lens spotlight whose emitted light beam has a variable aperture angle, having a preferably ellipsoid reflector, a lamp and at least one Fresnel lens, which has a more compact form and is thus not only more space-saving but is also lighter than a conventional Fresnel lens spotlight, a lens with a negative focal length and a virtual focal point is used as the diffusing glass.
Full Text Description
The invention relates to a Fresnel lens spotlight, whose
emitted light beam has an adjustable aperture angle, having a
reflector, a lamp and at least one Fresnel lens.
Those parts of conventional Fresnel lens spotlights which are
relevant for lighting purposes generally comprise a lamp, a
Fresnel lens and a spherical auxiliary reflector. The lamp
filament is conventionally located essentially in a fixed
position at the center of the sphere of the spherical
reflector. In consequence, a portion of the light which is
emitted from the lamp is reflected back into it, and assists
the light emission in the front hemisphere. This light which
is directed forwards is focused by the Fresnel lens. The
degree of light focusing is, however, dependent on the
distance between the Fresnel lens and the lamp. If the lamp
filament is located at the focal point of the Fresnel lens,
then this results in the narrowest light beam. This results
in a quasi-parallel beam path, which is also referred to as a
spot. The aperture angle of the emerging light beam is
continuously enlarged by shortening the distance between the
Fresnel lens and the lamp. This results in a divergent beam
path, which is also referred to as a flood.
Spotlights such as these have the disadvantage, however, that
the light yield is poor, particularly in their spot position,
since in this case only a relatively small spatial angle
range of the lamp is covered by the Fresnel lens. A further
disadvantage is that a large proportion of the light which is
reflected by the spherical reflector strikes the lamp
filament itself again, where it is absorbed and additionally
heats up the lamp filament.
DE 39 19 643 Al discloses a spotlight having a reflector, a
diaphragm and a Fresnel lens. The illumination produced by
the spotlight is varied by moving the light source, which
varies the brightness of the light. The brightness is
regulated by regulating the distance between the apex and the
reflector, and between the diaphragm and the reflector.
DE 34 13 310 Al discloses a spotlight having a lamp and a
reflector, or a lamp and a convergent lens. The spotlight
also has a diffusing glass or a mirror, both of which are
positioned at an angle of 45°. The mirror deflects the light,
and the light is scattered by the diffusing glass. Different
light beam emission angles are produced by moving the
diffusing glass.
DE 101 13 385 C1 describes a Fresnel lens spotlight in which
the Fresnel lens is a convergent lens whose focal point on
the light source side is located approximately at the focal
point of the ellipsoid reflector which is remote from the
reflector when in the spot position. The distances between the focal points of
the reflector, the focal length of the reflector and the focal length of the Fresnel
lens thus add up to the minimum length of a Fresnel lens spotlight such as this.
However, the invention is intended to provide a Fresnel lens spotlight which has
a more compact form and, in consequence, is more space-saving and also lighter
than a conventional Fresnel lens spotlight.
Thus object is achieved in a surprisingly simple manner by a Fresnel lens
spotlight whose emitted light beam has an adjustable aperture angle, having a
preferably ellipsoid reflector, a lamp and at least one Fresnel lens, wherein the
Fresnel lens is a lens with a negative focal length, and is therefore a negative
lens with a virtual focal point and by a lighting set comprising a Fresnel lens
spotlight of the present invention as well as an associated electrical power supply
unit or ballast.
The use of a Fresnel lens with a negative focal length makes it possible to
achieve an extremely compact form which, for example in the spotlight position
of the Fresnel lens spotlight, now corresponds essentially only to the length of
the reflector together with the thickness of the respectively used Fresnel lens.
The Fresnel lens spotlight according to the invention results in considerably
better light efficiency, particularly in the spot position, but also in the flood
position.
At the same time, the uniformity of the lighting intensity is maintained
over the entire light field, as is illustrated, by way of example, from
Figure 7, both for the spot position and for a flood position.
According to the invention, an ellipsoid reflector with a
large aperture is provided. The spot position is set such
that the lamp filaments of a black body emitter, in
particular of a halogen lamp, or the discharge arc of a
discharge lamp is located at the focal point of the ellipsoid
on the reflector side, and the second focal point of the
ellipsoid, which is remote from the reflector, is arranged
approximately at the negative or virtual focal point of the
Fresnel lens which is remote from the reflector.
The light which is reflected by the reflector is focused
virtually completely on the focal point of the ellipsoid
which is remote from the reflector, before it enters the
negative lens. The lamp filament which is located at the
focal point on the reflector side, or the discharge arc, is
imaged at infinity after passing through the Fresnel lens,
and its light is thus changed to a virtually parallel beam.
The reflected light essentially no longer strikes the lamp
filament or the discharge arc. The virtual negative focal
point of the Fresnel lens coincides with the focal point of
the reflector ellipsoid which is remote from the reflector,
and thus results in an extremely compact form.
If the aperture angle of the reflector and of the Fresnel
lens is chosen expediently, the light which is reflected by
the reflector virtually all passes through the Fresnel lens
and is emitted forwards as a narrow spot beam.
The light yield is thus considerably greater than in the case
of a conventional Fresnel lens spotlight.
The aperture angle of the light beam which emerges from the
Fresnel lens can be enlarged virtually indefinitely in a
first embodiment by varying the lamp position with respect to
the reflector on the one hand, and by varying the distance
between the Fresnel lens and the reflector on the other hand,
in a suitable manner.
In order to retain the good characteristics of conventional
Fresnel lens spotlights with respect to the uniformity of the
illumination intensity, these distance changes should be
carried out by means of expediently chosen positive coupling.
One embodiment of the invention comprises the ellipsoid
reflector being composed of a metallic or transparent
material. Glass and polymer materials or plastics are
preferably used, which may advantageously be coated with
metal, for example aluminum.
Alternatively or additionally in order to produce a
reflective surface, one of the two or both surfaces of the
reflector is or are provided with a system of optically thin
layers. In consequence, visible radiation components are
advantageously reflected, and the invisible components, in
particular thermal radiation components, are passed through.
A further preferred embodiment of the invention comprises a
metallic coating on one or both main surfaces of the
reflector.
In a further alternative refinement, the reflector may also
be a metallic reflector which may either be uncoated or else
may be dielectrically or metallically coated, in order to
produce the desired spectral and corrosion characteristics.
One preferred embodiment of the invention comprises a Fresnel
lens spotlight in which the light-reflective surface of the
reflector is structured such that it scatters light, and
none, one or two surfaces of the Fresnel lens is or are
structured such that it or they scatter light. This results
in a fixed proportion of the superimposition of scattered
light with respect to geometrically/optically imaged light,
which avoids the lamp being imaged in the light field. The
reflector for this purpose preferably has surface elements or
facets which allow its light-scattering components to be
calculated and to be manufactured in a defined manner.
With increasing miniaturization of the light source, for
example in the important field of digital projection or in
the case of high-power discharge lamps, it is, however,
possible for an ever more strongly pronounced central dark
area to occur, which cannot be compensated for, or can be
compensated for only with major light losses, by means of
scattering devices within the reflector. The conventional
scattering devices which are used to avoid imaging of the
emission center of the light source overcome this only to a
limited extent, if at all, since in this case as well at
least the dark central opening sphere must be illuminated
homogeneously in every position of the Fresnel lens
spotlight. However, particularly in the spot position, this
results in excessive light losses since only a dark area with
a very small aperture angle is present here but,
nevertheless, the complete area of the Fresnel lens is used
to scatter the light field in conventional Fresnel lenses
with scattering devices.
The inventors have found that these high light losses can be
avoided in a surprisingly simple manner. In this case, it is
particularly advantageous for the Fresnel lens to have a
diffusing glass which, in a particularly preferred manner, is
circular and is now just arranged at the center of the
Fresnel lens.
In this embodiment the dark areas in the center of the
illuminated field can be avoided very effectively in every
position of the Fresnel lens spotlight, without this leading
to major light losses while the reflector is in the spot
position.
Surprisingly, it has been found that the geometrical/optical
beam path of the light which emerges from the reflector
illuminates a smaller area at the position of the Fresnel
lens precisely when the required proportion of scattered
light is increased.
The inventors have made use of this effect in order, by means
of the invention, to create an automatic or adaptive light
mixing system which, in synchronism with the movement of the
Fresnel lens spotlight, mixes with the
geometrically/optically imaged light only that scattered
light component which is required for this position.
This lighting mixture ratio, which can be virtually optimally
matched to the respectively required light distributions, is
referred to only as the mixing ratio in the following text,
for short.
This automatic light mixing system results in the correct
mixing ratio essentially for every position of the
reflector, a very homogeneously illuminated light field
thus always being created, without unnecessary scattering
losses occurring, however, at the same time.
In this case, the mixing ratio of the completely illuminated
Fresnel lens can be defined by the choice of the diameter of
the integrated diffusing glass with respect to the remaining
area of the Fresnel lens, and the aperture angle of the
scattered light can be defined by the scattering
characteristics of the negative lens.
Furthermore, the scattering effect on the integrating
diffusing glass itself may vary so that, for example, more
strongly scattering areas are arranged in the center of the
diffusing glass and less strongly scattering areas are
arranged at its edge. In consequence, a relatively highly
focused beam is additionally also widened, and extremely wide
illumination angles can then be achieved.
Alternatively, the edge of the diffusing glass may also not
only end abruptly but may be designed such that its
scattering effect decreases continuously, and may also extend
under or above the Fresnel lens. This allows further
adaptations to the position-dependent mixing ratios.
Reference is made to the application, submitted on the same
date, by the same applicant entitled "Optische Anordnung mit
Stufenlinse" [Optical Arrangement with a Fresnel lens], whose
disclosure content is also included completely, by reference,
in the disclosure content of the present application.
According to the invention, the spotlight is intended to be
used for architecture, medicine, film, stage, studio and
photography as well as in a flashlight.
The diffusing glass in the preferred embodiments may be
arranged either on the light inlet side or on the light
outlet side. Furthermore, it is advantageously possible to
arrange diffusing glasses at the light inlet or on the light
outlet side. In this last-mentioned embodiment, it is also
possible to use diffusing glasses with different scatter, for
example diffusing glasses which scatter differently in
different positions.
The invention will be described in more detail using
preferred embodiments and with reference to the accompaying
drawings, in which:
Figure 1 shows an embodiment of the Fresnel lens spotlight
in the spot position, with the focal point of the
reflector which is remote from the reflector being
approximately superimposed on the virtual focal
point of the Fresnel lens on the right-hand side,
Figure 2 shows the embodiment of the Fresnel lens spotlight
as shown in Figure 1 in a first flood position,
with the focal point of the reflector which is
remote from the reflector being arranged
approximately on a surface of the Fresnel lens
which is close to the reflector,
Figure 3 shows the embodiment of the Fresnel lens spotlight
as shown in Figure 1 in a second flood position
with a larger aperture angle, with the focal point
of the reflector which is remote from the reflector
being imaged by the Fresnel lens in front of that
surface of the Fresnel lens which is remote from
the reflector,
Figure 4 shows the embodiment of the Fresnel lens spotlight
as illustrated in Figure 1 in a third flood
position with an even larger aperture handle than
in the second flood position, with the focal point
of the reflector which is remote from the reflector
being imaged by the Fresnel lens in front of that
surface of the Fresnel lens which is remote from
the reflector, and with the light source being
moved toward the reflector, from the focal point
which is close to the reflector,
Figure 5 shows the embodiment of the Fresnel lens spotlight
as shown in Figure 1 in its second flood position
with a larger aperture angle, with a further
portion of the light initially being passed by
means of an auxiliary reflector into the reflector
and from there into the Fresnel lens,
Figure 6 shows a negative Fresnel lens with a centrally
arranged diffusing glass,
Figure 7 shows a logarithmic representation (which is
dependent on the aperture angle) of the light
intensity of the Fresnel lens spotlight in its spot
position and in one of its flood positions.
Figure 8 shows a characteristic for the positive coupling
between the variables a and b, with the parameters
for the Fresnel lens, for the elliptical reflector
and for the luminaire being chosen by way of
example.
Detailed description of preferred embodiments
In the following detailed description, the same
reference symbols are used to denote the same elements or
elements having the same effect in each of the various
embodiments.
The following text refers to Figure 1, which shows one
embodiment of the Fresnel lens spotlight in the spot
position. The Fresnel lens spotlight essentially contains an
ellipsoid reflector 1, a lamp 2 which may be a halogen lamp
or else a discharge lamp, and a Fresnel lens 3, which is a
lens with negative refractive power, preferably a biconcave
Fresnel lens.
In Figure 1, the focal point F2 of the ellipsoid reflector 1
which is remote from the reflector is approximately
superimposed on the virtual or negative focal point F3 of the
Fresnel lens 3 on the right-hand side.
The light beam 4 which is emitted from the spotlight is
indicated only schematically in the figures by its outer edge
beams.
The distances a between the Fresnel lens 3 and the front edge
of the reflector 1, and b between the lamp 2 and the apex of
the reflector 1, are likewise shown in Figure 1.
The spot position is set by arranging the lamp filament or
the discharge arc of the lamp 2 essentially at the focal
point Fl of the reflector ellipsoid 1 on the reflector side.
The light which is reflected by the reflector 1 is, in this
position, directed virtually completely at the focal point F2
of the ellipsoid 1 which is remote from the reflector. The
right-hand side negative or virtual focal point F3 of the
Fresnel lens 3 then coincides approximately with the focal
point F2 of the reflector ellipsoid 1.
The near field in Figure 1 also shows how the opening 5
within the reflector 1 acts as a dark area 6 in the parallel
beam path of the light field 4.
A circular, centrally arranged diffusing glass 7 is provided
within the Fresnel lens 3, and produces a defined scattered
light ratio and a defined aperture angle of the scattered
light. This results in a defined mixing ratio of the
scattered light relative to the light which is
geometrically/optically imaged by the Fresnel lens 3.
As alternative to this embodiment of the diffusing glass 7,
the scattering effect in a further embodiment changes along
the radius of the diffusing glass 7 continuously, such that
more strongly scattering areas are arranged at the center of
the diffusing glass 7, and less strongly scattering areas are
arranged at its edge, which ends abruptly.
In yet another alternative refinement, the edge of the
diffusing glass 7 is not only designed such that it ends
abruptly, but is also designed such that its scattering
effect decreases continuously, and this may also extend under
or above the Fresnel lens.
In consequence, further adaptations to the position-dependent
mixing ratios are carried out as a function of the system, so
that a person skilled in the art can always provide an
optimum mixing ratio for a homogeneously illuminated light
field or else for light fields with locally higher
intensities which are produced in a defined manner.
Figure 1 also shows that only a small proportion of the total
light passes through the diffusing glass 7 in the spot
position.
The diffusing glass 7 results in very homogeneous
illumination, as is shown by the line 8 for the spot position
in Figure 7, which shows a logarithmic representation (which
is dependent on the aperture angle) of the light intensity of
the Fresnel lens spotlight.
Figure 2 shows the embodiment of the Fresnel lens spotlight
as illustrated in Figure 1 in a first flood position, in
which the focal point F2 of the reflector 1 which is remote
from the reflector is arranged approximately on a surface of
the Fresnel lens 3 which is close to the reflector.
In this case, the value of the shift a with respect to the
spot position is changed in a defined manner by means of a
mechanical guide.
Fundamentally, the design corresponds to the design of the
Fresnel lens spotlight explained in Figure 1.
However, as can clearly be seen from Figure 2, both the
aperture angle of the emitted light beam 4 and that of the
dark area 6 have increased.
However, since a very large proportion of the light in this
position strikes only a very small area in the center of the
diffusing glass 7, this area can in fact be designed such
that its forward scattering lobe compensates approximately
for the dark area 6 in the far field or far area in a
desired manner. Reference should also be made to Figure 1,
which shows the light conditions with the line 9, for example
for a flood position.
The foreign text refers to Figure 3, which shows the
embodiment illustrated in Figure 1 of the Fresnel lens
spotlight in a second flood position with an even larger
aperture angle than in Figure 2, with the focal point F2 of
the reflector 1 which is remote from the reflector being
imaged by the Fresnel lens 3 in front of that surface of the
Fresnel lens 3 which is remote from the reflector.
In this case, a larger area of the diffusing glass 7 has
light passing through it than shown in Figure 2, and its
overall scattering behavior can be matched to the
relationships of this flood position.
As is illustrated in Figure 4, the beam 4 is widened further,
as an alternative to or in addition to the flood position
shown in Figure 3, by varying the distance b between the lamp
2 and the reflector 1. Moving the lamp 2 towards the
reflector 1 once again focuses the light beam leaving the
reflector more strongly, leading to increased emission angles
after emerging from the Fresnel lens 3.
The change in the distance a and in the distance b may in
further embodiments be carried out, for example, by hand,
mechanically, electrically, electronically or in combination
with one another, in which case the optical components may be
guided axially for this purpose.
In order to retain the uniformity of the illumination
intensity, the distance changes in one particularly
preferred embodiment are, however, carried out by means of
expediently chosen positive coupling, which maintains a
defined relationship between the change in a and b.
The relationship between the variables a and b that is
defined by means of the positive coupling is governed by the
parameters used for the Fresnel lens, for the integrated
diffusing glass, for the elliptical reflector and for the
luminaire. The parameters in this case include the
dimensions, the geometry, the structure and the optical
characteristics of the individual components.
In particular, the parameters used for the Fresnel lens
include its optical diameter, its focal length, its
curvature, its light-scattering structure and its arrangement
on the front and/or rear face of the Fresnel lens; the
parameters fbr the diffusing glass which is integrated in the
Fresnel lens are its optical diameter, its light-scattering
structure and its arrangement; the parameters for the
elliptical reflector are its optical diameter, its curvature,
its focal length, its surface structure, the distance between
the two focal points and the diameter of the lamp bushing,
and the parameters for the luminaire are its shape, its
dimensions, its position and the nature of the luminaire, for
example in the form of a metal vapor discharge lamp, halogen
lamp or CDM lamp. Parameters which are not mentioned
expressly here may result in further influences.
As an example, Figure 8 shows a characteristic for the
positive coupling between the variables a and b. The
parameters used for the Fresnel lens, for the elliptical
reflector and for the luminaire are chosen, for example, as
follows:
Fresnel lens: with an optical diameter of 160 mm and a
negative focal length of 108.7 mm, an integrated diffusing
glass with a diameter of 28 mm at the center (honeycomb:
diagonal 3.4 mm, radius 4 mm, 3° twist), rear face with a
light-scattering structure;
elliptical reflector: with an optical diameter of 160 mm and
a focal length of 35 mm, a distance of 160 mm between the two
focal points, lamp guide with a diameter of 30 mm;
luminaire: a cylinder in the axial position, approximately
7.2 mm long, diameter approximately 2.6 mm.
A change in the parameters leads to a change in the
relationship between" the variables a and b defined by means
of the positive coupling. This results in a change in the
functional relationship for the characteristic defining the
positive coupling.
Figure 5 shows a further preferred embodiment. In this
embodiment, which corresponds essentially to the embodiments
described above except for having an additional auxiliary
reflector 18, the auxiliary reflector 18 deflects the light
from the lamp 2 (which would propagate to the right in Figure
5 and would no longer reach the reflector 1) into the
reflector 1 by reflection. In consequence, not only can the
light which is represented merely by way of example by the
beam path 19 and which would not contribute to the
illumination without the auxiliary reflector be used, but it
is also possible to use that portion of the light which
otherwise enters the Fresnel lens 3 directly better for the
desired light distribution.
The shape of the auxiliary reflector 18 is advantageously
chosen such that light which is reflected on it does not
enter the means of producing light in the lamp 2 again, for
example a filament or a discharge zone, and does not
unnecessarily heat it as well.
Alternatively, the auxiliary reflector 18 may be fitted to
the inner face and/or outer face of the glass body of the
lamp 2. The glass of the lamp body may be appropriately
shaped for this purpose, in order to achieve the desired
directional effect for the reflected light.
By way of example, Figure 6 shows a Fresnel lens 3 with a
diffusing glass 7, as is used by the invention. The Fresnel
lens 3 has a transparent base body 10 as well as a Fresnel
lens ring system 11 with annular lens sections 11, 12, 13,
between which the circular diffusing glass 7 is arranged.
The diffusing glass 7 is structured in a defined manner or
has facets 15, 16, 17 with a scattering behavior which can
defined exactly within wide limits, which facets 15, 16, 17
are described in German Patent Application DE 103 43 630.8
from the same applicant entitled "Streuscheibe" [Diffusing
glass], which was submitted to the German Patent and
Trademarks Office on September 19. The disclosure content o
this application is also in its entirety included by
reference in the disclosure content of this application.
However, the invention is not restricted to these already
described embodiments of diffusing glasses.
The Fresnel lens spotlight described above is particularly
advantageously used in a lighting set together with an
electrical power supply unit or ballast, which is
considerably smaller than in the case of the prior art.
This power supply unit can be designed both electrically and
mechanically to be smaller for the same usable light power
than in the case of the prior art, since the Fresnel lens
spotlight according to the invention has a considerably
higher light yield. Less weight is therefore required, and a
smaller storage space is occupied for transportation and
storage.
However, particularly when using cold light reflectors, this
also reduces the total thermal load on illuminated people and
objects.
Furthermore, the Fresnel lens spotlight according to the
invention can advantageously also be used to increase the
light yield from flashlights in which, in principle, the
available electrical energy is more severely limited.
List of reference symbols
1 Reflector
2 Lamp
3 Fresnel lens
4 Emitted light beam
5 Opening in the reflector 1
6 Dark area
7 Diffusing glass
8 Intensity distribution in the spot position
9 Intensity distribution in the flood position
10 Base body
11 Fresnel lens ring system
12 Annular lens sections
13 Ditto
14 Ditto
15 Facet
16 Ditto
17 Ditto
18 Auxiliary reflector
19 Beam path reflected by the auxiliary reflector
WE CLAIM
1. A Fresnel lens spotlight whose emitted light beam has an adjustable
aperture angle, having a preferably ellipsoid reflector, a lamp and at
least one Fresnel lens, wherein
the Fresnel lens is a lens with a negative focal length, and is therefore
a negative lens with a virtual focal point, characterized in that,
said virtual focal of said Fresnel lens and a focal point of said reflector
which is remote from said reflector can be superimposed outside the
Fresnel lens spotlight.
2. The Fresnel lens spotlight as claimed in claim 1, wherein said virtual
focal point of said Fresnel lens and said focal point of said reflector can
be superimposed in the spot position.
3. The Fresnel lens spotlight as claimed in claim 1 or 2, wherein the
Fresnel lens is a preferably biconcave negative lens.
4. The Fresnel lens spotlight as claimed in claim 1, 2 or 3, wherein the
Fresnel lens comprises a double lens with chromatically corrected
imaging characteristics.
5. The Fresnel lens spotlight as claimed in any one of the preceding
claims, comprising a Fresnel lens with an integrated diffusing glass.
6. The Fresnel lens spotlight as claimed in claim 5, wherein the diffusing
glass is circular and is arranged at the center of the Fresnel lens and
defines a light mixing system which varies the proportion of the
scattered light relative to the proportion of the geometrically / optically
imaged light, that is to say the light mixing ratio, as a function of the
position of the Fresnel lens spotlight.
7. A Fresnel lens spotlight, wherein the distance (a) between the Fresnel
lens and the reflector can be varied in a defined geometric relationship
with respect to the distance (b) between the lamp and the reflector on
the basis of the aperture angle to be set for the light beam which
emerges from the spotlight.
8. The Fresnel lens spotlight as claimed in claim 7, wherein the distance
(b) can be adjusted by arranging the lamp such that it can be moved
with respect to the jpex of the reflector.
9. The Fresnel lens spotlight as claimed in one of the preceding claims,
wherein the reflector is composed of a metallic or transparent,
preferably dielectric material, such as glass and / or plastic.
10. The Fresnel lens spotlight as claimed in one of the preceding claims,
with at least one of the two main surfaces of the reflector being
provided with a system of optically thin layers.
11. The Fresnel lens spotlight as claimed in one of the preceding claims,
wherein at least one of the two main surfaces of the reflector is coated
with metal, preferably aluminum.
12. The Fresnel lens spotlight as claimed in one of the preceding claims,
with the light-reflecting surface of the reflector being structured such
that it scatters light, preferably having surface elements or facets, and
none, one or two surfaces of the Fresnel lens is or are structured such
that it or they scatter light in addition to the diffusing glass.
13. The Fresnel lens spotlight as claimed in one of the preceding claims,
wherein the reflector, the Fresnel lens and / or the diffusing glass are /
is coated on at least one side.
14. The Fresnel lens spotlight as claimed in claim 13, wherein the coating
on the Fresnel lens comprises a dielectric interference layer system
which changes the spectrum of the light passing through it.
15. The Fresnel lens spotlight as claimed in one of the preceding claims,
wherein the lamp is an incandescent lamp, in particular a halogen
lamp, a light-emitting diode, a light-emitting diode array or a gas
discharge lamp.
16. The Fresnel lens spotlight as claimed in one of the preceding claims,
wherein an auxiliary reflector is arranged between the Fresnel lens and
the reflector.
17. The Fresnel lens spotlight as claimed in one of the preceding claims,
wherein the Fresnel lens is prestressed, preferably thermally
prestressed, on its surface.
18. A lighting set comprising a Fresnel lens spotlight as claimed in one of
the preceding claims 1 to 18, as well as an associated electrical power
supply unit or ballast.
19. A flashlight having a Fresnel lens spotlight as claimed in one of the
preceding claims 1 to 18.

In order to provide a Fresnel lens spotlight whose emitted
light beam has a variable aperture angle, having a preferably
ellipsoid reflector, a lamp and at least one Fresnel lens,
which has a more compact form and is thus not only more
space-saving but is also lighter than a conventional Fresnel
lens spotlight, a lens with a negative focal length and a
virtual focal point is used as the diffusing glass.

Documents:

851-kol-2004-abstract.pdf

851-kol-2004-assignment.pdf

851-kol-2004-claims.pdf

851-KOL-2004-CORRESPONDENCE-(12-12-2011).pdf

851-KOL-2004-CORRESPONDENCE-1.1.pdf

851-kol-2004-correspondence.pdf

851-kol-2004-description (complete).pdf

851-kol-2004-drawings.pdf

851-kol-2004-examination report.pdf

851-kol-2004-form 1.pdf

851-kol-2004-form 18.pdf

851-kol-2004-form 2.pdf

851-kol-2004-form 26.pdf

851-KOL-2004-FORM 27-1.1.pdf

851-KOL-2004-FORM 27.pdf

851-kol-2004-form 3.pdf

851-kol-2004-form 5.pdf

851-kol-2004-form 6.pdf

851-KOL-2004-FORM-27.pdf

851-kol-2004-granted-abstract.pdf

851-kol-2004-granted-claims.pdf

851-kol-2004-granted-correspondence.pdf

851-kol-2004-granted-description (complete).pdf

851-kol-2004-granted-drawings.pdf

851-kol-2004-granted-examination report.pdf

851-kol-2004-granted-form 1.pdf

851-kol-2004-granted-form 18.pdf

851-kol-2004-granted-form 2.pdf

851-kol-2004-granted-form 26.pdf

851-kol-2004-granted-form 3.pdf

851-kol-2004-granted-form 5.pdf

851-kol-2004-granted-form 6.pdf

851-kol-2004-granted-priority document.pdf

851-kol-2004-granted-reply to examination report.pdf

851-kol-2004-granted-specification.pdf

851-kol-2004-granted-translated copy of priority document.pdf

851-KOL-2004-PA-CERTIFIED COPIES-(12-12-2011).pdf

851-KOL-2004-PA.pdf

851-kol-2004-priority document.pdf

851-kol-2004-reply to examination report.pdf

851-kol-2004-specification.pdf

851-kol-2004-translated copy of priority document.pdf


Patent Number 237905
Indian Patent Application Number 851/KOL/2004
PG Journal Number 03/2010
Publication Date 15-Jan-2010
Grant Date 12-Jan-2010
Date of Filing 22-Dec-2004
Name of Patentee AUER LIGHTING GMBH
Applicant Address HILDESHEIMER STR. 35, 37581 BAD GANCERSHEIM
Inventors:
# Inventor's Name Inventor's Address
1 RUDIGER KITTELMANN BIRKENWEG 5, DE-37574, EINBECK
2 HARRY WAGENER ESCHENBACHSTRASSE 12, DE-31061 ALFELD
PCT International Classification Number F21V 7/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10361117.7 2003-12-22 Germany
2 102004 014045.6 2004-03-19 Germany