EP3765783B1 - Spotlights having controllable light distribution - Google Patents

Description

The present invention relates to a headlight for stationary mounting in an indoor or outdoor space, in particular to stadium headlights, and in particular to headlights with LEDs (which means any form of semiconductor light sources, including organic LEDs) arranged in a cluster in the headlight are.

In headlights of the type mentioned at the outset, a precise arrangement of lens elements and reflector elements has become established for controlling the direction of the light. The light distribution curve to be generated, LVK, which should generally be rotationally symmetrical in a conic curve, have a given half divergence angle and a maximum luminous intensity, which preferably lies along the optical axis of the headlight. Depending on the lighting task, eg to illuminate a soccer field, certain levels of illuminance must be achieved. This can only be achieved by superimposing different LDCs with different half beam angles and maximum light intensities, since the position of the spotlights in the stadium is different and the distance between the spotlights and the area to be illuminated is different. As a result, different LVKs and thus different optical components or movable optical systems are required in the headlight. This is relatively complex, since the optical components either have to be adapted for the individual LEDs or the LED clusters, or a complex adjustment mechanism has to be inserted within the headlight for the optical components.

Lighting devices with one or more LED clusters, some of which also have optics, are disclosed in the following publications: U.S. 2015/009677 A1 , U.S. 2009/046453 A1 , WO 2014/117704 A2 , U.S. 2012/068615 A1 , U.S. 2012/319616 A1 , U.S. 2017/002987 A1 and EP 2 985 512 A1 .

The object of the present invention is to provide a stationary headlight whose light distribution with LEDs can be adapted to the local conditions for fulfilling the lighting task in the simplest possible way.

The problem is solved by a headlight according to claim 1.

A special feature of the headlight according to the invention is that the LEDs within a cluster can be switched on and off and/or dimmed independently of at least some of the other LEDs within the cluster. As a result, different LDCs can be achieved by a cluster, possibly with an associated optical component of the cluster. Both symmetrical and asymmetrical LDCs can be achieved by switching LEDs on and off within the cluster depending on the design of the cluster and the different patterns in which the LEDs are switched on and off within the cluster. By independently dimming the LEDs within the cluster, the LVKs can even be continuously transformed into each other. In a cluster, LEDs that are not needed for the desired light distribution of the headlight simply cannot be fitted on the LED circuit board. A continuous transformation of the LVKs is then only possible to a limited extent due to the remaining LEDs in the cluster.

According to the invention, the cluster has common optics for all LEDs in the cluster. For example, a reflector and/or a lens, in particular a lens with total internal reflection, can be provided for all LEDs in the cluster. However, the optical component does not have to be changed to adjust the LVK. It is fixed to the LEDs in the cluster and the light is distributed by switching the LEDs on and off or dimming them within the cluster. This is a significant advantage compared to the systems in the prior art, in which a lens or a reflector has to be moved in a complex manner relative to the light sources or has to be manufactured individually for the headlight in order to fulfill the special lighting task according to the local conditions of the headlight be able.

According to a preferred embodiment, the cluster is formed by a square matrix of LEDs. For example, an LED cluster may include a 3x3, 4x4, or 5x5 matrix of LEDs. The larger the cluster, the more variations are possible for switching the LEDs within the cluster. The larger the basic cluster, the more different assembly variants of LEDs are possible.

According to a further embodiment, the cluster can also be formed by two LED rows running perpendicular to one another or rectangular LED matrices running perpendicular to one another.

According to the invention, the LED cluster has an arrangement of LEDs that is symmetrical to two mirror planes, the mirror planes having the perpendicular bisector through the cluster as a common line of intersection and being perpendicular to one another. This symmetry of the LED cluster is suitable for circular light distributions and also light distributions that extend in different directions along the main axes of the mirror-symmetrically arranged LEDs by switching LEDs on and off in a targeted manner or by dimming LEDs. By switching the LEDs asymmetrically within the symmetrical arrangement, asymmetrical LDCs can also be achieved with this arrangement. In general, this type of LED cluster offers a high degree of variation in terms of the light distribution to be achieved.

According to the invention, the headlight also has a plurality of the clusters mentioned above, which are arranged in the headlight at a distance from one another, and in particular in a regular array. By providing several clusters, the luminous intensity of the headlight is increased overall, since the light from the individual clusters is superimposed. The clusters can all be designed identically and arranged identically to one another. In this version, the LEDs within the cluster can also be controlled identically. This results in the same advantage as in the previously mentioned embodiments in relation to the variation of the light distribution, with the light intensity being increased overall. However, this embodiment also offers the advantage that the different clusters can be controlled differently. Entire clusters can be switched on or off. Furthermore, the LEDs within the cluster can be switched on and off or dimmed differently. As a result, a very high variation in the LVKs to be achieved is possible.

The multiple clusters each individually have associated optics, e.g. B. a reflector or a lens, preferably a lens with total internal reflection on.

According to a further development of the last-mentioned embodiments with a plurality of clusters, the clusters can also be arranged in the headlight with different rotations to one another. As a result, the LVKs of the individual clusters are superimposed to form an overall light distribution that differs from the light distribution of the individual clusters. For example, asymmetries in the overall light distribution can be compensated for, which the individual clusters would produce due to the shape of the cluster.

Figur 1

zeigt eine 3x3-LED-Cluster.

Figur 2

zeigt ein 3x3-Array mit jeweils einem 3x3-LED-Cluster.

Figuren 3a - 3c

zeigen die LVK und den Lichtstrom eines 3x3-LED-Cluster, wobei eine, fünf bzw. neun LEDs eingeschaltet sind.

Figur 4

zeigt ein 4x4-LED-Cluster.

Figur 5

zeigt ein 5x5-LED-Cluster.

Figuren 6 und 7

zeigen das 5x5-LED-Cluster, wobei LEDs in unterschiedlichen Musters eingeschaltet sind.

Figuren 8a und 8b

zeigen eine Schnittansicht eines 3x3-LED-Clusters mit Totalreflexionslinse, wobei nur eine bzw. alle LEDs eingeschaltet sind.

Figur 9

zeigt ein näherungsweise rundes LED-Cluster mit 37 LEDs.

Figur 10

zeigt ein Array mit zwei unterschiedlichen LED-Cluster.

Figur 11

zeigt ein Array mit zwei gleichen LED-Cluster.

Further features and advantages of the present invention will become clear from the following description of preferred embodiments given in connection with the attached figures. The figures show the following:

figure 1

shows a 3x3 LED cluster.

figure 2

shows a 3x3 array, each with a 3x3 LED cluster.

Figures 3a - 3c

show the LDC and the luminous flux of a 3x3 LED cluster, with one, five or nine LEDs switched on.

figure 4

shows a 4x4 LED cluster.

figure 5

shows a 5x5 LED cluster.

Figures 6 and 7

show the 5x5 LED cluster with LEDs turned on in different patterns.

Figures 8a and 8b

show a sectional view of a 3x3 LED cluster with a total reflection lens, with only one or all LEDs switched on.

figure 9

shows an approximately round LED cluster with 37 LEDs.

figure 10

shows an array with two different LED clusters.

figure 11

shows an array with two identical LED clusters.

Referring to figure 1 a single LED cluster 2 is shown. It comprises nine LEDs 1 arranged in a 3x3 matrix.

In its simplest form, only one LED cluster is required to form a headlight. According to a preferred embodiment, which is figure 2 However, as shown, multiple of the LED clusters 2 are provided in the headlight to form a multiple cluster array. The clusters 2 are each arranged at a distance a in the array. The distance a between the clusters and their nearest neighbors (measured from center to center) is greater than the distance between the LEDs 1 within the cluster.

In the embodiments of the present invention, the LEDs within the clusters can be switched on and off or dimmed individually. The influence of this circuit on the light intensity distribution curve (specified in the light intensity normalized to the total luminous flux), the light intensity (absolute), the half beam angle and the luminous flux in the various switching states is shown in the Figures 3a to 3c shown.

Figure 3a shows the 3x3 LED cluster in which only the middle LED 4 is switched on and the remaining LEDs 5 are switched off or are not populated on the circuit board. Figure 3b shows the case in which only the four outer LEDs 5 are switched off or are not present on the circuit board and the remaining LEDs 4 are switched on. Figure 3c shows the case that all nine LEDs 5 of the 3x3 LED cluster are switched on. Since the optical components of the cluster are always the same, the LEDs that are switched on differently result in different LDCs or luminous fluxes and efficiencies. In Figure 3a is the greatest luminous intensity (Imax1) in relation to the total luminous flux of the luminaire. The half peak angle (half peak angle 1) is the lowest and at the same time the luminous flux is at the lowest value at Imax1. If more LEDs 4 are switched on, as in Figure 3b shown, the half beam angle increases, Imax2 decreases and the luminous flux increases. When all LEDs 4 are operational, as in Figure 3c shown, the maximum luminous flux in relation to the total luminous flux drops to the lowest value Imax3, while the half beam angle assumes the highest value. The luminous flux in Imax3 is the highest.

the Figures 4 and 5 show alternatives for the LED cluster. In figure 4 an LED cluster 6 is shown with a 4x4 matrix of LEDs. figure 5 shows an LED cluster 7 in the form of a 5×5 matrix. The larger clusters allow a higher variation of patterns in which the LEDs can be switched on and off or dimmed. In particular, symmetrical or oval light distribution curves can also be generated using switching states of the LEDs, as in Figures 6 and 7 are shown. In figure 6 an asymmetrical LVK is generated in that in the 5x5 matrix of the LED cluster 7 only 3x3 LEDs 4 are operated in one corner, while the other LEDs 5 are switched off. In the figure 7 will LEDs 4 turned on, which are turned on symmetrically about a central axis of the LED cluster 7 of the 5x5 matrix. In this circuit state, an oval LVK can be generated. The details of asymmetric or oval LVK each relate to an LVK measured in a section of the envelope of a cone perpendicular to the optical axis of the headlight, which runs along the perpendicular bisector of the cluster.

In the embodiment after Figures 8a and 8b a lens 3 is provided above a 3×3 LED cluster 2. The lens 3 includes a light entry area and a light exit area at which light radiation is refracted. Furthermore, the lens 3 also has side wall areas at which light rays are totally reflected. Different beam paths in the lens are activated by switching on or off individual LEDs 4, 5 in the LED cluster. In Figure 8a only the middle LED 4 is switched on while all other LEDs 5 are switched off. Due to the fact that only a middle LED 5 is switched on, the light beams L11, L12 and L13 leave the lens 3 almost parallel and thus produce a high Imax or a small half divergence angle. In contrast, in Figure 8b all nine lenses 5 of the 3x3 LED cluster switched on. Due to the fact that the light-emitting surface is larger, light beams L21 and L22 from the outer LEDs are added, which no longer leave the lens 3 in parallel. This creates a lower Imax in relation to the total luminous flux or a larger half beam angle and at the same time an increased luminous flux.

In the embodiment according to figure 9 an LED cluster 8 is shown, in which the LEDs approximate a circle. Embodiments with LED clusters, in which the LEDs are mirror-symmetrical to two on top of one another, are very general perpendicular vertical mirror planes are aligned, preferred because they can approximate a circular shape and are therefore particularly suitable for the usual optical devices.

The high number of LEDs 1 - in figure 9 37 pieces in total - are preferred to create a wide variety of possible LVKs.

In figure 10 an embodiment is shown in which a cluster 11 with 5 LEDs arranged in a cross shape is combined with only a single LED 12 in an array.

figure 11 10 shows an arrangement with dimmed LEDs in two clusters 10. The outer four LEDs in a 3×3 cluster are dimmed by around 50%. This results in an Imax that is between an arrangement with nine LEDs on and an arrangement with five LEDs on. A stepless setting of Imax or the half-value angle is therefore possible.

Numerous variations of the embodiments described above are possible within the scope of the invention, which is defined by the claims. For example, different combinations of nxn clusters can be used. Asymmetric clusters are also possible. In preferred embodiments, individual LEDs within a cluster that are not required for the desired light distributions can also be omitted completely. In this case, a blank is simply provided at the relevant point in the cluster. However, the remaining LEDs in the cluster are controllable as previously described.

REFERENCE LIST

1

LEDs

2

3x3 LED cluster

3

lens

4

LED, switched on

5

LED, off

6

4x4 LED cluster

7

5x5 LED cluster

8th

LED cluster with 37 LEDs

11

cross-shaped LED cluster

12

single LED

a

Spacing of the LED clusters in the array

Claims (7)

1. A headlamp for stationary mounting in an interior or exterior space, in particular a stadium headlamp,
   the headlamp comprising a plurality of clusters (2, 6, 7, 11) each having a plurality of LEDs (1), the clusters being arranged in the headlamp at a distance from one another, wherein individual ones of the LEDs in each of the clusters can be switched on and off and/or dimmed independently of at least some of the remaining LEDs in the cluster, wherein each of the clusters has its own optical system (3) for all the LEDs in the relevant cluster in each case, and wherein the LED clusters each have an arrangement of LEDs which is symmetrical to two mirror planes, wherein the mirror planes have the perpendicular bisector through the cluster as common degrees of intersection and are perpendicular to one another, characterized in that the LEDs in each of the clusters can be switched and/or dimmed separately in different patterns, which are each symmetrical with respect to said mirror planes, and the LEDs can also be switched or dimmed in patterns which are asymmetrical with respect to said mirror planes, wherein asymmetrical switching of the LEDs within the symmetrical arrangement achieves an asymmetrical light distribution curve.
2. The headlamp according to claim 1, wherein the optics are formed by a reflector and/or a lens, in particular by a lens (3) with total internal reflection.
3. The headlamp according to any one of the preceding claims, wherein the clusters (2, 6, 7) are each formed by a square matrix of LEDs (1).
4. The headlamp according to claim 3, wherein the LED clusters (2, 6, 7) are each formed by a 3x3, 4x4 or 5x5 matrix of LEDs.
5. The headlamp according to any one of claims 1 to 3, wherein the clusters (11) are each formed by two LED lines running perpendicular to one another or rectangular LED matrices running perpendicular to one another.
6. The headlamp according to any one of the preceding claims, wherein the clusters (2, 6, 7, 11) are arranged in the headlamp rotated relative to one another.
7. The headlamp according to any one of the preceding claims, wherein at least two clusters (2, 6, 7, 11) have a different number, arrangement and/or color of LEDs.

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