EP0696705B1 - Indirect lighting device - Google Patents

Abstract

<P>The lighting unit has a main reflector (1) formed from two identical reflector shells (11,2) that are located symmetrically about a centre axis (2). Located within the main reflector is an auxiliary reflector unit (4) that has a pair of surfaces (41,42). The lighting tube (5) is positioned between the surfaces. The auxiliary reflector arrangement and the lighting tube can be moved vertically (6) to vary the effect. The auxiliary reflector provides an indirect lighting effect.

Description

The invention relates to a secondary lamp according to the preamble of claim 1.

Secondary lights, which are also referred to as indirect lights, are known in a large number of embodiments, for example from EP-B1-0 201 926. These types of luminaires have in common that a light source is arranged within a main reflector arrangement, the outer edges of which delimit a light outlet opening of the luminaire, which is shielded in the direction of this light outlet opening by a counter-reflector which encompasses the light source to such an extent that no direct light component can exit directly from the luminaire . This means that the light source is not visible to a viewer of the luminaire itself, and therefore a high luminance of the light source cannot immediately cause glare to the viewer.

In the known secondary lights, the main reflector is often designed in cross-section as a conical cut surface or composed of parts of conical cut surfaces, these conical cut surfaces colliding above this light source in a light axis of symmetry in which the light source is also arranged. In conjunction with the smaller counter or auxiliary reflector located below the light source, it is thereby achieved that all light emitted by the light source is directed either directly or after, if necessary, multiple reflections onto the main reflector, from where, after being reflected again, through the light exit opening of the luminaire on the counter reflector exits. The counter-reflector of known secondary lights is designed and arranged in relation to the light source in such a way that light incident on it is reflected and, if possible, directed past the light source onto the main reflector. In the angular range The main reflector is formed directly above the light source so that light striking it there is preferably not reflected back into the light source in order to avoid light losses which would reduce the luminaire efficiency. Nevertheless, the efficiency of luminaires in known secondary luminaires is not completely satisfactory, since for the reasons described it is inevitable that the light emitted by the light source may be reflected several times at the auxiliary and / or main reflector before it can exit through the light exit opening.

With this principle of secondary technology, it remains unavoidable that, in addition to a portion of light that is emitted through the light exit opening after a single reflection at the main reflector, a relatively high portion of the light emitted by the light source is reflected at least twice before it emerges through the light exit opening of the lamp can. In such secondary lights, it has always been the aim to limit the number of reflections on the counter and main reflector for as large a proportion of the directly emitted light as possible without having to accept that light is reflected back into the focal spot of the light source itself . In the known luminaire shapes, despite optimized designs in the main and auxiliary reflector arrangement, even with appropriate choice of materials, it has not been possible to improve the luminaire efficiency significantly.

Furthermore, from DE-A1-38 07 584 an operating light is known which has rotationally symmetrical inner reflectors arranged at a predetermined axial distance from one another, between which a point-shaped light source is arranged. An outer ring reflector is arranged coaxially with these inner reflectors, whose direction of emission is essentially transverse to the central axis of the luminaire. In terms of lighting technology, this luminaire arrangement is designed in such a way that an illumination level is set in the illumination plane, which is characterized by concentrically adjoining ring surfaces each having at least approximately the same illuminance. This is achieved in that the reflection surfaces of the inner reflectors consist of a plurality of annular zones with a corresponding angle of inclination with respect to the reflector axis and a predetermined radial width. Surgical lights are very bright lights to achieve a high level of lighting in the surgical field. On the other hand, surgical interventions must also be carried out using a screen, and this high level of lighting can lead to reflex glare. For this reason, the lamp can be moved axially out of the space between the inner reflectors or a diaphragm is provided to darken the light source. This prevents the light source from being switched off if the high level of illumination interferes with and subsequent re-ignition.

The present invention is therefore based on the object of providing a further embodiment of a secondary luminaire of the type mentioned at the outset, which allows the light emitted by the light source to be guided with the least possible loss of light, ie with high luminaire efficiency, to realize different light distributions. According to the invention this object is achieved in a secondary lamp of the type mentioned with the features described in the characterizing part of claim 1.

According to the teaching of the invention, the counter-reflector known in secondary luminaires is designed to form an auxiliary reflector arrangement which has at least two mirror surfaces, one of which, like the known secondary reflector, completely shields the light source in the direction of the light exit opening of the luminaire. The second mirror surface of this auxiliary reflector arrangement is facing away from the light exit opening with respect to the light source, that is to say is arranged above the light source. Compared to known secondary lights, this additional mirror surface of the auxiliary reflector arrangement, which is located inside the light, initially appears to be superfluous and rather disadvantageous, since in this case a much larger proportion of the light emitted by the light source - in contrast to known secondary lights - is additionally reflected on this inner mirror surface. This seems to run counter to the demand for high luminaire efficiency. The opposite is the case, however, if the mirror surfaces of this auxiliary reflector arrangement are designed with respect to the light source and aligned with respect to one another such that all light emitted by the light source is directed towards the main reflector arrangement essentially transversely to the axis of symmetry of the light, after reflection at most at this auxiliary reflector arrangement. from where, with a corresponding curve shape of the surfaces of the main reflector arrangement, it can exit through the light exit opening of the luminaire after in turn directed only once.

Regardless of the choice of material, it is crucial in the known secondary lights to determine the shape and position of the main reflector and counter-reflector with respect to the position and beam characteristics of the light source used. In the solution according to the invention, however, is actual optimization in the design of the auxiliary reflector arrangement which forms a modular unit with the light source. This not only has constructive advantages because the relatively small surfaces of the auxiliary reflector arrangement can be produced in an optimized manner with fewer tools, but also enables greater freedom of movement in the lighting design of such a secondary lamp.

This is particularly clear in a development of the invention according to claim 2. This development, in contrast to conventional secondary lights, allows different light distributions to be implemented in a simple manner with one and the same secondary light. Such a light distribution does not always have to be permanently set at the installation site of the lamp. Rather, it is easily conceivable by simple devices, such as a continuously variable transmission, to manually position the modular unit consisting of auxiliary reflector arrangement and light source relative to the main reflector arrangement in order to obtain a desired more wide-beam or narrow-beam lamp characteristic, corresponding to diverse application purposes. For example, a headlamp or a projector lamp with adjustable light intensity distributions could be realized.

As further developments of the invention described in further subclaims show, it is possible to use the solution according to the invention with a large number of different luminaire shapes which can also be equipped with a wide variety of light sources with regard to the respective intended use. A wide range of applications is thus given for the solution according to the invention.

• Figur 1 in einem Querschnitt die Prinzipdarstellung einer ersten Ausführungsform einer erfindungsgemäßen Sekundärleuchte mit einer Hilfsreflektoranordnung, deren Spiegelflächen in Form sich durchdringender Parabeln ausgebildet sind,
• Figur 2 in der gleichen Art der Darstellung eine weitere Ausführungsform, bei der die Spiegelflächen der Hilfsreflektoranordnung in Form sich durchdringender Ellipsen ausgebildet sind,
• Figur 3 sowie Figur 4 eine dritte Ausführungsform, bei der die Spiegelflächen der Hilfsreflektoranordnung in Anpassung an die Brennergeometrie einer ausgewählten Lichtquelle unterschiedlich ausgebildet sind, wobei im Vergleich beider Figuren gezeigt ist, wie sich bei unveränderter Hilfsreflektoranordnung die Lichtverteilungskurve der Sekundärleuchte durch Vertikalverschiebung dieser Hilfsreflektoranordnung von einer breit strahlenden zu einer tief strahlenden Charakteristik verändern läßt,
• Figur 5 die Anwendung der gemäß der Figuren 1 bis 4 dargestellten Prinzipien bei einer langgestreckten Leuchte,
• Figur 6 eine weitere Ausführungsform für eine Sekundärleuchte mit horizontal angeordneter Lichtquelle und rechteckiger Lichtaustrittsöffnung und
• Figur 7 ein Beispiel für eine Rundleuchte mit vertikal angeordneter Lichtquelle.

Embodiments of the invention are described below with reference to the drawing. It shows

• 1 shows in a cross section the basic illustration of a first embodiment of a secondary lamp according to the invention with an auxiliary reflector arrangement, the mirror surfaces of which are designed in the form of penetrating parabolas,
• FIG. 2 shows another embodiment in the same type of representation, in which the mirror surfaces of the auxiliary reflector arrangement are designed in the form of interpenetrating ellipses,
• Figure 3 and Figure 4 shows a third embodiment in which the mirror surfaces of the auxiliary reflector arrangement are designed differently to match the burner geometry of a selected light source, it being shown in a comparison of the two figures how the light distribution curve of the secondary lamp changes with an unchanged auxiliary reflector arrangement due to vertical displacement of this auxiliary reflector arrangement from one broad-beam to deep-radiating characteristics,
• 5 shows the application of the principles shown in FIGS. 1 to 4 in an elongated lamp,
• FIG. 6 shows a further embodiment for a secondary lamp with a horizontally arranged light source and a rectangular light outlet opening and
• Figure 7 shows an example of a circular lamp with a vertically arranged light source.

A basic illustration of a secondary lamp is shown in cross section in FIG. This luminaire has a main reflector 1, which consists of two identical reflector shells 11 and 12 with a contour in the form of a conic section, these reflector shells 11, 12 being arranged mirror-symmetrically with respect to a luminaire symmetry axis 2 at a predetermined distance from one another. The outer Edges of the reflector shells 11 and 12 of the main reflector 1 delimit a light exit opening 3 of the secondary light, which lies in a plane perpendicular to the light symmetry axis 2.

An auxiliary reflector arrangement 4 is shown in the interior of the main reflector 1, facing away from the light exit opening 3. This auxiliary reflector arrangement 4 has mirror surfaces 41 and 42, which in this example are designed in the contour as conic section lines. These are mutually penetrating parabolas, with the penetration points lying in the axis of symmetry 2 and the common parabolic axis being perpendicular and transverse to the axis 2 of symmetry. A light source 5 is arranged in the focal plane 43 of this auxiliary reflector arrangement 4, which contains this parabolic axis and is perpendicular to the light symmetry axis 2, and is deliberately shown almost point-like in this basic illustration of FIG. This is intended to illustrate that this type of luminaire is preferably used, although not exclusively approximately point-shaped or line-shaped light sources are to be used with advantage.

As will be explained in more detail later, the light source 5 is integrated in the auxiliary reflector arrangement 4, i. H. both lamp components together form a modular unit in the secondary lamp. A double arrow 6 schematically indicates that this modular unit consisting of auxiliary reflector arrangement 4 and light source 5 integrated therein is arranged to be longitudinally displaceable along the lamp axis of symmetry 2 with respect to the main reflector 1. In this way, the light distribution curve of the secondary lamp can be adjusted as desired, as will be explained in more detail in further embodiments.

Furthermore, there are still various to illustrate the lighting function of the secondary lamp according to Figure 1 Light rays 71 and 72 are shown as examples. In the case of the light beams 71, these are light beams of the first type, namely light beams which, starting from the light source 5, strike the main reflector 1, here the reflector shell 11, and emerge from there after only one reflection through the light exit opening 3 . With light rays of the second type, the light rays 72, it is illustrated how light that emerges at larger radiation angles, in relation to the focal plane 43, is first reflected once on one of the mirror surfaces 41 and 42 of the auxiliary reflector arrangement 4 and only then onto the main reflector 1 , here in the example the reflector shell 12 strikes and exits from there after renewed reflection through the light exit opening 3 of the secondary lamp.

The examples of the beam path shown make it clear that the light emerging from the light source 5 is preferably directed transversely to the axis of symmetry 2 of the light by the funnel-shaped configuration of the auxiliary reflector arrangement 4, wherein it is reflected at most once before it hits the main reflector 1. Thus, all light emitted by the light source 5 is reflected at most twice before it passes through the light exit opening 3 of the secondary lamp. The cross-sectional shape of the mirror surfaces 41 and 42 of the auxiliary reflector arrangement 4 created by the penetration of the parabolas ensures that no light can be reflected back into the light source 5 itself by the auxiliary reflector arrangement 4.

FIG. 2 uses another example to explain the design options that this luminaire structure provides. In comparison to FIG. 1, matching or comparable luminaire elements are identified by the same reference numerals, so that repetitions in the description can be avoided. In contrast to the luminaire shape according to FIG. 1, the auxiliary reflector arrangement 4 is used in this further exemplary embodiment formed from mirror surfaces 41 and 42, the contours of which are interpenetrating ellipses, the interpenetration points in turn lying on the light axis of symmetry 2. In adaptation to this design of the auxiliary reflector arrangement 4, the two reflector shells 11 and 12 of the main reflector 1 are pulled apart a little further. Overall, the luminaire shape in this exemplary embodiment is relatively flatter and shows, by way of example, a light distribution which emits a rather narrow beam compared to the embodiment according to FIG.

Another embodiment is shown in FIG. 3. This example is to illustrate that the mirror surfaces 41 and 42 of the auxiliary reflector arrangement 4 can also be designed completely different while maintaining the lighting principle. While in the examples according to FIG. 1 and FIG. 2, the mirror surfaces 41, 42 of the auxiliary reflector arrangement 4 are mirror-symmetrical with respect to the focal plane 43, the mirror surfaces 41 and 42 in the embodiment according to FIG. 3 have a completely different contour. All that remains here is the symmetry of the main reflector 1 and the auxiliary reflector arrangement 4 with respect to the light symmetry axis 2. This example shows that it is easily possible, while maintaining the lighting principle of the lamp structure, the auxiliary reflector arrangement 4 freely to the light intensity distribution of a lamp selected for a specific application as light source 5, d. H. especially to adapt to their burner geometry. This already shows in principle that this type of luminaire can be used expediently in conjunction with a wide variety of light sources and that the person skilled in the art is thus offered a large number of design options.

FIG. 4 shows the embodiment of the secondary lamp according to FIG. 3 again. In comparison to the illustration according to FIG. 3, this example is intended to show how the light distribution curve of the secondary lamp changes when one the position of the modular unit of the luminaire formed from the auxiliary reflector arrangement 4 and the light source 5 is shifted relative to the main reflector 1 by a longitudinal movement in the direction of the luminaire symmetry axis 2. In the case of the illustration according to FIG. 4, this modular unit 4, 5 of the secondary lamp is drawn deeper into the main reflector 1, ie it is at a greater distance from the light exit surface 3 of the lamp. With this change in position in the direction of arrow 6 ', the light distribution curve of the secondary lamp changes due to the conical contour of the reflector shells 11 and 12 of the main reflector 1 from a more broadly radiating characteristic (FIG. 3) to a preferably narrowly radiating characteristic (FIG. 4).

FIG. 5 shows an example of the application of this principle of the lamp structure described above with reference to FIGS. 1 to 4 for a secondary lamp in a linear lamp. Here, a rod-shaped fluorescent lamp, possibly also a compact fluorescent lamp, comes into consideration as the light source 5. The auxiliary reflector arrangement 4 with the mirror surfaces 41 and 42 corresponds approximately to the embodiment described with reference to FIG. 1.

A rectangular luminaire is shown schematically in FIG. 6, in which case the main reflector 1 is accordingly composed of four reflector shells. In this exemplary embodiment too, the light source 5 is arranged in a horizontal position, it being designed as a high-pressure lamp, for example of the HQI-TS type. However, this too is only one example of the possible use of very bright lamps with a focal spot which, however, can no longer be viewed as a point. Again, the auxiliary reflector arrangement 4 is composed of mirror surfaces 41 and 42, which are arranged perpendicularly and transversely to the light axis of symmetry. In this case too, the mirror surfaces 41, 42 are formed from intersecting conical surfaces, so that parallel to the axis of the light source 5 to the two of them Sides each have a cutting or penetrating edge running perpendicular to the axis of symmetry of light 2. This provides the prerequisite for directing all light emitted by the light source 5 away from it in the direction of one of the reflector shells of the main reflector 1.

Finally, FIG. 7 shows an embodiment of a secondary lamp which differs in certain details from the exemplary embodiments described above. A circular lamp is selected as an example of the luminaire shape. The main reflector, which is rotationally symmetrical here in this exemplary embodiment, could, however, also be composed of a large number of facet mirrors in such a way that a regular polygon would result in a cross section of the lamp in a plane perpendicular to the axis of symmetry of the lamp 2.

However, the vertical position of the modular light deflection unit formed from the auxiliary reflector arrangement 4 and the light source 5 is more important than the previously described embodiments. Again, a high pressure lamp, e.g. B. of the type HQI-TS or HQI-T or a similar lamp with a relatively short burner. Now, however, this vertical arrangement of the light source 5 means that it must be passed through the mirror surfaces 41 and 42 of the auxiliary reflector arrangement. With the design of the mirror surfaces 41 and 42, which here - corresponding to the shape of the main reflector 1 - are also rotationally symmetrical, it is then no longer possible to use the mirror surfaces of the auxiliary reflector arrangement 4 up to the two theoretical penetration points of the rotating bodies of the mirror surfaces in the axis of symmetry 2 of the light . That is, In this embodiment, the mirror surfaces 41 and 42 must be cut off beforehand in order to be able to pass the light source 5 through.

At first, this design-related deviation from an ideal shape of the auxiliary reflector arrangement 4 appears - at least theoretically - to be a certain disadvantage. In fact, however, this is not the case. As practice has shown, the luminaire efficiency is hardly noticeably affected because the advantages of the vertical arrangement far outweigh them. This is due to the fact that short-arc lamps of the type mentioned above and similar high-intensity lamps have a butterfly-like light distribution, viewed in a plane containing the lamp longitudinal axis. In other words, this lamp type only emits an almost negligible proportion of light at maximum light emission in the direction perpendicular and transverse to the lamp longitudinal axis in the direction close to the axis. However, since the vertical arrangement of the light source in this circular luminaire according to FIG. 7, which is suitable as a headlight or parallel projector, is already making optimal use of the free emission of such a lamp type, the design of the auxiliary reflector arrangement 4 intensifying this effect, in this application the result of the necessary implementation of the light source 5 being complete the auxiliary reflector arrangement 4 unavoidable theoretical light loss in practice is negligible.

The variety of the embodiments described above has demonstrated the performance of the described lamp structure of a secondary lamp. Even if it is not possible to use almost punctiform or linear light sources in all applications, as is theoretically desirable, the exemplary embodiments described have shown that adaptation of the geometry of the main reflector and, in particular, of the auxiliary reflector arrangement to the peculiarities of a specific light source is so largely possible is that in practice light losses in the luminaire can be avoided as far as possible, even under difficult boundary conditions, that luminaire efficiencies can still be achieved which are often not possible with other, conventional secondary luminaires.

Claims (10)

1. Indirect luminaire having a main reflector arrangement (1), whose outer edges bound a light exit opening (3) of the indirect luminaire, having a light source (5) arranged within this main reflector arrangement, and having an auxiliary reflector arrangement (4) which has reflective surfaces (41, 42) which are located at a distance from each other and which, considered in the direction of a luminaire axis of symmetry (2) located at right angles to the light exit opening (3), are arranged in front of and behind the light source (5) and are designed to open at the sides transversely to this luminaire axis of symmetry (2), characterized in that the auxiliary reflector arrangement (4) forms, with the light source (5), a modular unit in which light source (5) and reflective surfaces (41, 42) are located at a prescribed distance from one another and which is arranged so that it can be moved longitudinally in the direction of the luminaire axis of symmetry (2) in relation to the main reflector arrangement (1).
2. Indirect luminaire according to Claim 1, characterized in that the auxiliary reflector arrangement (4) has roof-shaped reflective surfaces (41, 42) which, considered in a luminaire cross-section along the luminaire axis of symmetry (2), have roof edges which lie on this axis and in each case face the light source (5) and which have a flat contour or a contour designed as a conical section line.
3. Indirect luminaire according to Claim 2, characterized in that the reflective surfaces (41, 42) of the auxiliary reflector arrangement (4), in relation to a plane which is drawn at right angles to the luminaire axis of symmetry (2) and through the focal length of the light source (5), are designed with mirror symmetry.
4. Indirect luminaire according to Claim 3, characterized in that the reflective surfaces (41, 42) of the auxiliary reflector arrangement are designed as conical sectional surfaces in whose focal point plane (43), directed at right angles to the luminaire axis of symmetry (2), the light source (5) is arranged and which surfaces pass through each other on the luminaire axis of symmetry (2).
5. Indirect luminaire according to one of Claims 2 to 4, characterized in that the main reflector arrangement (1) consists of reflector shells (11, 12) whose contour, considered in a luminaire cross-section along the luminaire axis of symmetry (2), form conical section lines which lie symmetrically in relation to this axis, open in the direction of the light exit opening (3) and, if necessary, are joined in sections.
6. Indirect luminaire according to Claim 5, which is designed as a luminaire having a rod-shaped light source (5) and has a luminaire plane of symmetry which is drawn between the luminaire axis of symmetry (2) and a luminaire longitudinal axis which is located at right angles to the said axis of symmetry and transversely thereto, characterized in that the main reflector arrangement (1) is constructed from two elongated reflector shells (11, 12) which are designed and arranged with mirror symmetry to each other in relation to the said luminaire plane of symmetry (2), and in that the likewise elongated auxiliary reflector arrangement (4 or 41, 42, respectively) is aligned parallel to the luminaire longitudinal axis in which the rod-shaped light source (5) is located.
7. Indirect luminaire according to Claim 5, characterized in that the main reflector arrangement (1) and the auxiliary reflector arrangement (4) are designed with rotational symmetry in relation to the luminaire axis of symmetry (2), and in that, as light source (5), a high-power lamp with a short focal length is used, which is arranged vertically and lying on the luminaire axis of symmetry (2).
8. Indirect luminaire according to Claim 5, characterized in that the main reflector arrangement (1) and the auxiliary reflector arrangement (4) are designed with rotational symmetry in relation to the luminaire axis of symmetry (2), and in that, as light source (5), a high-power lamp with a short focal length is used, which is arranged horizontally and lying transversely to the luminaire axis of symmetry (2).
9. Indirect luminaire according to Claim 5, characterized in that the main reflector arrangement (1) and the auxiliary reflector arrangement (4) are composed of a plurality of reflector shells (e.g. 11, 12) and reflective surfaces (e.g. 41, 42), each of which, considered in cross-sectional planes located at right angles to the luminaire axis of symmetry (2), are combined to form regular polygons, and in that, as light source (5), a high-power lamp with a short focal length is used, which is arranged vertically and lying on the luminaire axis of symmetry (2).
10. Indirect luminaire according to Claim 5, characterized in that the main reflector arrangement (1) and the auxiliary reflector arrangement (4) are composed of a plurality of reflector shells (e.g. 11, 12) and reflective surfaces (e.g. 41, 42), each of which, considered in cross-sectional planes located at right angles to the luminaire axis of symmetry (2), are combined to form regular polygons, and in that, as light source (5), a high-power lamp with a short focal length is used, which is arranged horizontally and lying transversely to the luminaire axis of symmetry (2).

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