EP0846913A1 - Spotlight with variable illumination output angle - Google Patents

Abstract

The headlamp has a variable radiation angle. There is a bulb (4), a reflector(5) assigned to it, and a first and a second collection lens (2,6) in the radiation path. The reflector, the bulb and the second lens are mounted as an optical unit that can move relative to the first lens along the optic axis of the headlamp. Inside this unit, the distance between the bulb and the second lens can be changed. The distance between the bulb and the reflector can also be changed. With a movement of the unit away from the first lens, the distance between the bulb and the reflector remains constant until the reflector has reached a distance from the first lens corresponding to the headlamp dimensions.

Description

The invention relates to a headlamp with variable Beam angle with a light source, one of the light sources assigned reflector, one in the radiation direction of the Light source-reflector combination arranged in the beam path first converging lens and one in the beam path between the Light source and the first converging lens arranged second Converging lens, the reflector, the light source and the second converging lens as one relative to the first converging lens optical moving along the optical axis of the headlamp Unit are mounted and inside the optical unit the distance between the light source and the second converging lens is changeable.

Headlights have long been state of the art known with variable beam angle. These can be essentially in two classes, namely stepped lens headlights and headlights with a very deep reflector.

Conventional step lens headlights have a single one Step lens (Fresnel lens) on. As a light source in these step lens headlights incandescent lamps, halogen lamps or discharge lamps are used. The light source and a Reflectors are on a sled at a fixed distance from each other assembled. The sled is relative to the Fresnel lens movable. The focus is done by moving the Sledge. With such step lens headlights results however, for focusing settings with a small beam angle a significant effective loss of light. Because no second lens is present that focuses the light towards the Fresnel lens, becomes a large part of the focusing settings mentioned of the light emitted by the light source simply by the Housing inner wall absorbs, leading to loss of light and too useless housing heating leads.

Headlights with a very deep reflector are common constructed so that lamp and reflector are relative to each other can be moved, but the lamp is always within of the reflector remains on its optical axis. By changing the position of the lamp within the reflector becomes the beam angle of such a headlamp changed. However, the focus path that can be achieved is low, so that the beam angle is only within relatively narrow limits can be varied. Such headlights provide one high luminous efficacy, but one in almost all lamp positions unfavorable light distribution. Cause of this in general bad light distribution is that for everyone such headlights each have a predetermined reflector shape with regard to the resulting light distribution only on each a single lamp position can be optimally coordinated. Result from focusing movements of the lamp or the reflector uneven light distributions. About the light distribution is to be improved in such a Headlights often use a replaceable front lens. This can be a matting, a honeycomb structure or others Design peculiarities that require an additional focus or serve scatter. So it results in these headlights the need for different Focus settings of differently modified front lenses to use. With some headlights with very low Both the lamp and the reflector are even reflectors rigidly mounted in a housing, i.e. the change of In this case, the light emission angle occurs exclusively by replacing differently designed front lenses. This requires a relatively high amount of work and time to change the front lens when such a headlight is applied in a situation where the focus position needs to be changed often.

Compared to the headlights just described significantly improved headlamp with variable beam angle is known from US-A-4,823,243. He has one Light source, a reflector assigned to the light source, one in the radiation direction of the light source-reflector combination arranged in the beam path and a first in Beam path between the light source and the first converging lens arranged second converging lens. The reflector, the The light source and the second converging lens are relative as one to the first converging lens along the optical axis of the headlight movable optical unit mounted. Within the optical unit is the distance between the light source and second converging lens changeable. The one from US-A-4 823 243 known headlights provide a large focusing range (see Fig. 4) and has a high efficiency achieved Illuminance in relation to that used to operate the headlamp required energy. Furthermore, that from US-A-4,823 243 known headlights have a light distribution that is so even is that the traditional concept of "cone and flare" can no longer be used. As from Fig. 4 can be seen, the illuminance characteristic has a illuminated field on a soft shoulder, however is the light intensity over the entire illuminated Range essentially constant.

The invention has for its object a headlight to provide with a variable beam angle, the one compared to the known headlights with variable Beam angle even higher variability of the beam angle and that offers light intensity.

According to the invention, this object is achieved by a Headlamp with variable beam angle with a Light source, a reflector assigned to the light source, one in the radiation direction of the light source-reflector combination arranged in the beam path first converging lens and one in the beam path between the light source and the first converging lens arranged second converging lens, the reflector, the light source and the second converging lens as one relative to the first converging lens along the optical axis of the Headlights movable optical unit are mounted, within the optical unit the distance between the Light source and the second converging lens is changeable and within the optical unit the distance between the Light source and the reflector is changeable.

The headlamp according to the invention with variable Beam angle has all the advantages of that of US-A-4 823 243 known headlights, but has a higher variability the beam angle and the light intensity. Despite the enlarged construction can focus the construction of the invention Headlights can be kept small.

In a preferred embodiment of the invention Headlamp, the optical unit is designed so that when the optical unit moves from the first Converging lens away the distance between the light source and the Reflector remains essentially constant until the Reflector one according to the headlight dimensions has reached the extreme distance to the first converging lens and in stops moving, and when the reflector stops moving in its extreme distance from the first converging lens is the light source a predetermined distance further towards the Reflector can be moved and reversed movement described first the light source at standstill of the reflector in the direction of the predetermined distance the first converging lens is moved and after passing the predetermined path through the light source of the reflector is moved so that the distance between the light source and the reflector remains essentially constant.

In this embodiment of the headlight according to the invention the focus area is particularly towards small angles extended. Furthermore, described by the Reducing the distance between the light source and the reflector the losses when focusing in the narrow angle Beam area significantly reduced. The change the illuminance is in the narrow-angle radiation range disproportionately in relation to the change in the beam angle large, resulting in a particularly strong increase in light intensity variability compared to the state of the art Technology known headlights results.

In another embodiment of the invention Headlamp, the optical unit is designed so that when the optical unit moves along the optical Axis at least part of the way the distance changed between the light source and the reflector.

It is particularly advantageous to use the optical unit in this way execute that the distance between the light source and the reflector when the optical unit moves from the first converging lens continuously shrinked away and at a movement of the optical unit to the first converging lens continuously increased.

Fig. 1a bis 1e schematisch einen Querschnitt einer Ausführungsform eines erfindungsgemäßen Scheinwerfers bei Bewegung einer aus Lichtquelle, Reflektor und zweiter Sammellinse bestehenden optischen Einheit aus einer dichtmöglichst an einer ersten Sammellinse befindlichen Position in eine weitmöglichst von der ersten Sammellinse entfernte Position,

Fig. 2a bis 2e schematisch einen Querschnitt einer weiteren Ausführungsform des erfindungsgemäßen Scheinwerfers bei Bewegung der aus Lichtquelle, Reflektor und zweiter Sammellinse bestehenden optischen Einheit aus der dichtmöglichst an der ersten Sammellinse befindlichen Position in die weitmöglichst von der ersten Sammellinse entfernte Position,

Fig. 3a bis 3f schematisch einen Querschnitt einer dritten Ausführungsform des erfindungsgemäßen Scheinwerfers bei Bewegung der aus Lichtquelle, Reflektor und zweiter Sammellinse bestehenden optischen Einheit aus der dichtmöglichst an der ersten Sammellinse befindlichen Position in die weitmöglichst von der ersten Sammellinse entfernte Position,

Fig. 4 Lichtverteilungskennlinien des aus der US-A-4 823 243 bekannten Scheinwerfers für verschiedene Fokussiereinstellungen und

Fig. 5 Lichtverteilungskennlinien des erfindungsgemäßen Scheinwerfers für verschiedene Fokussiereinstellungen.

Exemplary embodiments of the headlamp according to the invention with a variable beam angle are explained with reference to figures. Show it:

1a to 1e schematically a cross section of an embodiment of a headlamp according to the invention when an optical unit consisting of light source, reflector and second converging lens is moved from a position as close as possible to a first converging lens into a position as far as possible from the first collecting lens,

2a to 2e schematically show a cross section of a further embodiment of the headlight according to the invention when the optical unit consisting of light source, reflector and second converging lens moves from the position as close as possible to the first converging lens into the position as far away from the first collecting lens as possible.

3a to 3f schematically a cross section of a third embodiment of the headlamp according to the invention when the optical unit consisting of light source, reflector and second converging lens moves from the position as close as possible to the first converging lens into the position as far away from the first collecting lens as possible,

Fig. 4 light distribution characteristics of the headlight known from US-A-4 823 243 for various focusing settings and

Fig. 5 light distribution characteristics of the headlamp according to the invention for different focusing settings.

In Fig. 1a is an embodiment of the invention Headlight shown in cross section. The headlight has a cup-like, opaque housing 1, in that a first converging lens 2 is used on the light exit side is. Within the housing 1 are on a slide 3rd a light source 4 by a small filament lamp Helix is formed, and one assigned to the light source 4 Reflector 5 arranged. The light source 4 and the reflector 5 are mounted so that the resulting light beam path in Direction of the first converging lens 2 is directed. Besides, is on the slide 3 in the beam path between the light source 4 and the first condenser lens 2 is arranged a second condenser lens 6. In the illustrated embodiment of the invention Headlight, the second converging lens 6 is a meniscus lens with a crystalline etched concave surface, the convex surface in the direction of the first converging lens 2 points. The light source 4, the reflector 5 and the second Collective lens 6 are mounted so that both the distance between the light source 4 and the second converging lens 6 as also the distance between the light source 4 and the reflector 5 can be changed.

It is also possible to use both the first converging lens 2 as well as in the second converging lens 6 each have a lens surface to be grained so that a microlens structure arises. This measure makes one special good light distribution uniformity achieved.

Fig. 1a shows the light source 4, the reflector 5 and the second converging lens 6 in a position of maximum radiation angle of the headlight according to the invention. The distance between the first converging lens 2 and the second converging lens 6 as well the distance between the second converging lens 6 and the light source 4 are minimal according to the headlight dimensions, and the distance between the light source 4 and the reflector 5 is the maximum according to the installation conditions Distance.

To reduce the beam angle, the slide 3 moved in the direction away from the first converging lens 2. Here is the mechanics of the sled and cooperates with it Guide parts designed so that the second converging lens 6 initially remains in its original position and itself only the light source 4 and the reflector 5 while maintaining their original mutual distance in the direction of move the first converging lens 2 away. That kind of movement lasts until the distance between the light source 4 and the second converging lens 6 reaches a predetermined value Has. 1b shows the optical system of the invention Headlights in this position.

With further movement of the carriage 3 in the direction of the first converging lens 2 changes away, as in Fig. 1c shown, initially neither the distance between the light source 4 and the reflector 5, the distance between the light source 4 and the second converging lens 6. Each further the light source 4, the reflector 5 and the second Move the converging lens 6 away from the first converging lens 2, and so on the beam angle becomes smaller and the larger it is Illuminance on the illuminated field.

Finally, the reflector 5 reaches one accordingly the headlight dimensions extreme distance from the first Converging lens 2 and stops moving (see Fig. 1d). This is the position in which the one from US-A-4,823 243 known headlights its minimal beam angle and reaches its maximum illuminance.

In the embodiment shown in FIGS. 1a to 1e However, it is now the headlight according to the invention possible, the light source 4 and the second converging lens 6 below Maintaining their mutual distance stationary reflector 5 even further from the first converging lens 2 away and thus closer to the reflector 5 (see Fig. 1e).

A further embodiment is shown in FIGS. 2a to 2e of the headlight according to the invention. This embodiment of the headlamp according to the invention is essentially identical to that shown in Figures 1a to 1e Embodiment of the headlight according to the invention. Of the the only difference is that when the reflector 5 its extreme according to the headlight dimensions Has reached distance to the first converging lens 2 in the embodiment 2a to 2e also the second converging lens 6 not moved further away from the first converging lens 2 can be. In this case, only the light source 4 is below Maintaining the maximum mutual distance between second converging lens 6 and reflector 5 continue to the reflector 5 brought up as soon as the reflector 5 and the second converging lens 6 their greatest possible distance in this embodiment of the first converging lens 2 (see Fig. 2e). As a result, the beam angle of the invention Headlamps further reduced. For the expert, however It is particularly surprising that one in relation to the Reduction of the beam angle disproportionately large Increase in illuminance in the illuminated field results. Already with one carried out in the manner described further reducing the beam angle by a few Percent results in a function of the size of the light source Increase in light output by up to 32 percent. The means that with the help of the headlight according to the invention the loss of light when focusing in the narrow-angle range be greatly reduced.

4 and 5 show light distribution characteristics of the headlight known from US-A-4 823 243 (FIG. 4) and the embodiment of the headlight according to the invention described with reference to FIGS. 2a to 2e (FIG. 5). It can be seen that the headlight according to the invention has a somewhat larger radiation angle range and, particularly in the narrow-angle radiation range, offers a surprisingly greater variability in illuminance. Headlight type headlight according to the invention ARRI-Junior 300 plus ARRI-Junior 650 plus ARRI-Junior 1000 ARRI compact 200 W. Minimum beam angle α _min 7.5 ° 15 ° 12 ° 12 ° 9 ° Maximum beam angle α _max 52 ° 57 ° 55 ° 60 ° 50 ° Angular ratio α _max : α _min 6.9 3.8 4.6 5.0 5.6 Light intensity at maximum beam angle I _min at 3m from the headlight (relative units) 950 580 1450 1900 1120 Light intensity with minimum beam angle I _max at a distance of 3 m from the headlight (relative units) 12100 1800 7000 9500 7500 Focusing ratio I _max : I _min 12.7 3.1 4.8 5.0 6.7 Focus ratio / angle ratio 1.84 0.82 1.04 1.00 1.19

In the table above are characteristic data the described embodiment of the invention Headlights with corresponding data from the status of the Technology-owned headlights from ARRI compared.

While in the known from the prior art Headlamps the parameter focusing ratio: angle ratio is close to 1, achieves the mentioned parameter the headlight according to the invention has a value of almost 2. Also the absolute focusing ratio is in the case of the invention Headlights two to four times larger than those from the State of the art headlights.

The opposite of the sequence of movements described above Movement of the light source 4, the reflector 5 and the second converging lens 6 in the direction of the first converging lens 2 takes place in the shown embodiments of the invention Headlights in exactly the opposite order starting in the position shown in Fig. 1e / 2e over the in 1d / 2d, 1c / 2c and 1b / 2b shown positions to towards the position of Fig. 1a / 2a. With regard to the Figures 1a to 1e described embodiment of the invention Headlights initially only move Light source 4 and the second converging lens 6 while maintaining their mutual distance from the stationary reflector 5 away towards the first converging lens 2 (Fig. 1d). In the embodiment described with reference to Figures 2a to 2e of the headlamp according to the invention initially moves only the light source 4 away from the stationary reflector 5 in Direction towards the likewise stationary second converging lens 6 and thus in the direction of the first converging lens 2 (FIG. 2d). Is the predetermined maximum distance between the light source 4 and the reflector 5 reached move in both described Embodiments of the headlamp according to the invention the light source 4, the reflector 5 and the second converging lens 6 while maintaining their mutual distances the carriage 3 in the direction of the first converging lens 2 (FIG. 1c / 2c). Finally, the second converging lens 6 reaches her smallest possible distance to the first converging lens 2 (Fig. 1b / 2b), and the light source 4 and the reflector 5 while maintaining their mutual distance Moved towards the second converging lens 6 (Fig. 1a / 2a) until finally a predetermined maximum radiation angle is reached is.

The mechanical design of the carriage 3 and with it interacting guide parts should not be described in detail be a multitude of different Possibilities are known to a mechanical slide system build which the above with reference to FIGS. 1a to 1e or 2a to 2e movement sequence described.

In addition to mechanical slide systems, the ones described above There are others in making movements possible Embodiments of the headlamp according to the invention Sledge systems that cause slightly modified movements. For example, one embodiment of the headlamp according to the invention, the second converging lens 6 rear section of the movement of the carriage 3 from the first lens 2 is not suddenly, but it will at constant relative speed between the light source 4 and the first converging lens 2 the relative speed between the second converging lens 6 and the first converging lens 2 continuously slows down until the second converging lens 6 then finally stops while the reflector 5 and the light source 4 while maintaining their mutual Move the distance away from the first converging lens 2 (Fig. 3a to 3e). Finally, the reflector 5 reaches the one shown in FIG. 3e shown outermost position, and only the light source 4 moves away from the first converging lens 2 until also the Light source 4 has finally reached its outermost position (Fig. 3f). Moved when reversing this movement first the light source 4 onto the second converging lens 6 to while the reflector 5 and the second converging lens 6 stand still. Once a predetermined distance between the Light source 4 and the reflector 5 is reached, move both at the same speed on the second converging lens 6 to. Finally, a movement of the second converging lens sets 6 towards the first converging lens 2, whereby the speed of this movement continuously as long increases until finally the second converging lens 6, the Light source 4 and the reflector 5 while maintaining them mutual distances to migrate to the first converging lens 2. The further course of movement is then finally identical to the sequence of movements described with reference to the above Embodiments for the front part of the carriage movement, i.e. for the movement of the carriage 3 near the first converging lens 2 has been described. Also a sled system, the movements described in this section enables the specialist to a variety realizing different possibilities without difficulties can.

1a to 3f, the reflector 5 is always a relatively flat reflector and the light source 4 as one Filament lamp shown upright. However, it is also possible a deep reflector and / or a lying attached lamp to use. A particularly good light intensity increasing effect in the area of small beam angles arises when a lying lamp is in a deep reflector is retracted.

Instead of those mentioned in the above embodiment Filament lamp can also light source 4, for example a halogen lamp or a discharge lamp without a filament with a light spot between two electrodes. The In any case, light source 4 should be as small as possible being held.

Claims (4)

Headlights with variable beam angle with a light source (4), a reflector (5) assigned to the light source (4), a first converging lens (2) and arranged in the beam path in the radiation direction of the light source-reflector combination (4, 5) a second collecting lens (6) arranged in the beam path between the light source (4) and the first converging lens (2), wherein the reflector (5), the light source (4) and the second converging lens (6) are mounted as an optical unit which is movable relative to the first converging lens (2) along the optical axis of the headlamp and the distance between the light source (4) and the second converging lens (6) can be changed within the optical unit,
characterized in that the distance between the light source (4) and the reflector (5) is variable. Headlight according to claim 1, characterized in that the optical unit is designed so that when moving the optical unit away from the first converging lens (2) Distance between the light source (4) and the reflector (5) so remains essentially constant until the reflector (5) one according to the headlight dimensions Distance to the first converging lens (2) and in its Stops moving, and when the reflector (5) stops its extreme distance from the first converging lens (2) the light source (4) a predetermined distance further toward the reflector (5) can be moved and with a reversal the movement described first the light source (4) Standstill of the reflector (5) by the predetermined distance is moved towards the first converging lens (2) and after Passing the predetermined distance through the light source (4) the reflector (5) is moved so that the distance between the light source (4) and the reflector (5) essentially remains constant. Headlight according to claim 1, characterized in that the optical unit is designed so that at a Movement of the optical unit along the optical axis the distance between at least part of the way the light source (4) and the reflector (5) changed. Headlight according to claim 3, characterized in that the optical unit is designed so that the distance between the light source (4) and the reflector (5) at one Movement of the optical unit from the first converging lens (2) continuously reduced in size and with a movement of the optical unit to the first converging lens (2) continuously enlarged.

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