EP3889497A1 - Device with a light arranged above a work surface - Google Patents

Abstract

A device is described with a lamp (1) arranged above a work surface with a lamp and a reflector arranged above the lamp and directed towards the work surface (2). In order to be able to achieve mobile use as a floor lamp with glare-free, homogeneous illumination even of large work surfaces (2), it is proposed that the lamp (1) be arranged without overlapping next to the work surface (2), that the light source is a half-space radiator directed towards the reflector (5) and that the reflector is a free-form reflector (4) designed to uniformly illuminate the work surface (2).

Description

The invention relates to a device with a lamp arranged above a work surface with a lamp and a reflector arranged above the lamp and directed towards the work surface.

Devices for illuminating work surfaces are known from the prior art. Such devices include a lamp with a light source and with a reflector directed towards the work surface. In the case of work surfaces in particular, the most uniform possible illumination is desired, which is why the lamp is usually arranged centrally above the work surface on the ceiling. However, this requires corresponding electrical connections in the area above the work surface, so that on the one hand retrofitting in existing workplaces is extremely complex and on the other hand flexible workspace design is made more difficult because the device is firmly attached to a position on the ceiling. That is why efforts are made to use luminaires without fixed anchoring to illuminate work surfaces. This is from the EP1143194A1 known a floor lamp for illuminating a work surface. This has a lamp with a fluorescent tube as a light source, which is optionally surrounded by a reflector directed towards the work surface. If a desired work surface is to be illuminated, the lamp can be arranged accordingly above the work surface. Sufficient illumination should naturally be provided in that area of the work surface in which a person actually works, so that the device known from the prior art must be arranged directly above this person, i.e. usually above the center of a work table. However, this has the disadvantage that the radiation cone generated by the lamp blinds the person as soon as their gaze is directed away from the work surface. This is the case, for example, with typical work on a computer screen. In addition, the problem arises that the radiation cone generated by the illuminant or reflector predominantly illuminates the area of the work surface immediately below the lamp, so that additional devices are necessary for sufficient illumination of particularly large work surfaces, for example a double work table, which, however, results in inhomogeneous illumination due to the areas distributed over the work surface, each with different illuminance levels. In order to be able to adapt the radiation cone to different work surfaces without having to provide a large number of different devices for illuminating, it is known from the prior art to design the lights to be pivotable. For this purpose, the lamp can be pivoted about a vertical axis, as a result of which the position of the radiation cone with respect to the work surface can be changed. However, this in turn means that other areas of the work surface are less strongly illuminated, so that undesired hotspot formation cannot be avoided.

The invention is therefore based on the object of designing a device of the type described at the outset in such a way that mobile use as a floor lamp with glare-free, homogeneous illumination can also be achieved on large work surfaces.

The invention solves the problem in that the lamp is arranged without protrusion next to the work surface, that the light source is a half-space radiator directed towards the reflector and that the reflector is a free-form reflector designed to uniformly illuminate the work surface. As a result of these measures, a radiation cone can be generated which homogeneously illuminates the entire work surface, for example a partial area of a work table or the entire work table, without the lamp having to be arranged above the center of the work surface. The inventive arrangement of the lamp next to the work surface without overlapping glare prevents a person sitting at the work surface and looking forward, because the radiation cone does not intersect with the field of vision of the person. In addition to and without overhanging means in this case that the normal projection of the luminaire onto the work surface level is outside the work area. In order to achieve homogeneous illumination over the entire work surface in spite of the arrangement of the light next to the work surface, for example next to the shorter end of a work table, the reflector is a free-form reflector that deflects the light generated by a half-space spotlight, for example an LED, onto the work surface . The free-form reflector has different sections of curvature, so that with an appropriate design, a uniform illuminance over the entire work surface is made possible. In principle, different embodiments are possible for such a free-form reflector, which can be constructed with known calculation programs for designing such free-form reflectors.

In order to achieve homogeneous illumination both in the center and in the edge areas upstream and downstream of the center in the direction of the greatest extent of the work surface, especially in the case of particularly long work surfaces, it is proposed that the smallest distance between the half-space radiator and the free-form reflector along the direction of the largest expansion of the work surface from a near field lying on the side of the work surface to an opposite far field of the free-form reflector decreases. The near field of the free-form reflector is assigned to the edge area upstream of the center of the work surface in the direction of its greatest extent from the luminaire, while the far field of the free-form reflector is assigned to the edge area downstream of the center. The far field of the free-form reflector is more curved and has a smaller smallest distance to the half-space radiator than the near field of the free-form reflector. As a result, the radiation density of the radiation cone increases in the direction of the greatest extent of the work surface and thus with increasing distance from the luminaire, which enables a largely uniform illuminance over the entire work surface.

Particularly in the case of particularly large work surfaces, it may be desirable to accentuate certain areas, namely the central area where a person predominantly sits. In addition to a homogeneous basic illumination To enable such accentuation without disturbing the overall impression of homogeneous illumination, the half-space radiator can be in the area of a maximum curvature of the free-form reflector and the portion of the radiation cone emitted by the maximum curvature of the free-form reflector can be directed towards the longest extension of the work surface towards the center of the work surface. The curvature maximum lies in the transition area between the far field and the near field of the free-form reflector. As a result, the lighting in the area to be accentuated can be intensified, while the portions of the radiation cone of the far and near fields remain unaffected.

In order to achieve a smooth transition between the area to be accentuated and the rest of the work surface, it is proposed that the curvature of the free-form reflector decrease along the direction of the greatest extent of the work surface from the curvature maximum to the edge areas of the free-form reflector. This avoids sudden changes in illuminance. So that a direction-independent, uniform transition occurs, the decrease in curvature of the far field of the free-form reflector must be less than the decrease in curvature of the near field of the reflector.

So that the devices can be used for standard workplaces regardless of the size of the people in the work area, without having to carry out adaptations at the workplace itself, it is recommended in a preferred embodiment of the device according to the invention that the lamp be between 50 cm and 170 cm above the work surface is arranged and that the angle of the beam cone of the free-form reflector, which is limited by the vertical, is at least 36 ° in the direction of the longest extension of the work surface. The proposed angle of the radiation cone enables complete illumination of the work surface even after the height of the lamp has been adjusted in the intended area between 50 cm and 170 cm above the work surface. A standard workstation typically means tables with dimensions of 160 cm x 80 cm - 200 cm x 100 cm.

In order to further reduce any glare that remains despite the previous measures, the luminaire can comprise several free-form reflectors which are arranged transversely to the direction of the greatest extent of the work surface and have an overlapping radiation cone. The superimposition of the beam cone leads to a compression of the luminous flux, while the larger radiating surface on the luminaire itself reduces glare. In order to avoid a change in the lighting characteristics of the luminaire despite these measures, the illuminated surfaces generated by the radiation cones can be superimposed congruently on the work surface. The device can comprise only one half-space radiator, which illuminates the free-form reflectors arranged transversely to the direction of the greatest extent of the work surface, although each free-form reflector can also have one or more half-space radiators assigned to it.

So that a person bent over the work surface can also be prevented from being dazzled, it is proposed that the angle of the radiation cone of the free-form reflector, which is limited by the vertical, be at least 20 ° and at most 85 ° transversely to the direction of the longest extension of the work surface. The suggested angle enables complete and uniform illumination of common standard workplaces, even across the longest extension of the work surface.

In order to be able to use the device also for double workplaces and at the same time to be able to design the lighting characteristics of the two workplaces independently of one another, the lamp can comprise several free-form reflectors arranged transversely to the direction of the greatest extent of the work surface, which illuminate two adjacent, separate work surfaces. The half-space radiators assigned to these free-form reflectors can be controlled independently of one another. In the case of symmetrical double workplaces, it can be advantageous if the free-form reflectors for illuminating one work surface are designed to be mirrored to the free-form reflectors for illuminating the other work surface. So that glare can be further reduced in the case of lighting from only one work surface in the case of two opposite work surfaces, it is proposed that each free-form reflector be provided with optionally switchable groups of half-space radiators assigned to a work surface, with the emitted light per group of half-space radiators via the free-form reflector is directed towards the assigned work surface. In this way, the light emitted by the luminaire is always emitted over the entire luminaire surface, regardless of whether one or both work surfaces are illuminated. In a particularly preferred embodiment, all free-form reflectors can be designed to be the same and in particular symmetrical to a plane spanned by the direction of the greatest extent of the work surface and the vertical.

Particularly favorable structural conditions arise when the free-form reflectors assigned to a work surface are arranged on a carrier which protrudes from a base lying between the work surfaces in the direction of the one work surface. The carrier can be designed to be displaceable in order to carry out minor adaptations of the lights. The base can comprise a post with a stand so that the device can be designed as a floor lamp. In a preferred embodiment, in contrast to the normal projection of the lamp, the normal projection of the base on the work surface level at least partially overlaps with the work surface.

So that the device can be operated in an energy-efficient manner, it is proposed that a sensor for control be assigned to a half-space radiator. This means that the lights can be deactivated or dimmed when a person is absent from the work surface. If a person approaches the non-illuminated or dimmed work surface, the sensor detects this and activates the light for this work surface. Two sensors can also be provided, a first sensor the half-space radiators for illuminating a work surface and a second sensor the half-space radiators for illuminating another, adjacent to and separated from the one work surface Controls the work surface. This has the advantage that if a double workstation is simply occupied, both work surfaces do not have to be illuminated.

Fig. 1

eine perspektivische Darstellung einer Ausführungsform der erfindungsgemäßen Vorrichtung,

Fig. 2

einen Schnitt der Fig. 1 entlang der Linie II-II in vergrößertem Maßstab, schematischen Vollschnitt durch eine erfindungsgemäße Vorrichtung

Fig. 3

einen Schnitt der Fig. 1 entlang der Linie III-III in vergrößertem Maßstab,

Fig. 4

eine Draufsicht des Freiformreflektors,

Fig. 5

einen Schnitt der Fig. 4 entlang der Linie V-V in vergrößertem Maßstab,

Fig. 6

einen Schnitt der Fig. 4 entlang der Linie VI-VI in vergrößertem Maßstab,

Fig. 7

einen Schnitt der Fig. 4 entlang der Linie VII-VII in vergrößertem Maßstab und

Fig. 8

einen Schnitt der Fig. 4 entlang der Linie VIII-VIII in vergrößertem Maßstab.

In the drawing, the subject matter of the invention is shown, for example. Show it

Fig. 1

a perspective view of an embodiment of the device according to the invention,

Fig. 2

a cut of the Fig. 1 along the line II-II on an enlarged scale, schematic full section through a device according to the invention

Fig. 3

a cut of the Fig. 1 along the line III-III on an enlarged scale,

Fig. 4

a top view of the free-form reflector,

Fig. 5

a cut of the Fig. 4 along the line VV on an enlarged scale,

Fig. 6

a cut of the Fig. 4 along the line VI-VI on an enlarged scale,

Fig. 7

a cut of the Fig. 4 along the line VII-VII on an enlarged scale and

Fig. 8

a cut of the Fig. 4 along the line VIII-VIII on an enlarged scale.

A device according to the invention has, as for example in the Fig. 1 is shown, a lamp 1 for illuminating a plurality of work surfaces 2, which can be, for example, part or the entire surface of a work table or a double work station 3. According to the Fig. 2 the luminaire 1 has a light source and a reflector arranged above the light source. The reflector is against one to be illuminated in the Fig. 1 pictured work surface 2 directed. In order to prevent a person on the work surface 2 from being dazzled when looking up from the work surface 2, in particular when looking forward, the lamp 1 is arranged next to the work surface 2 so that it does not protrude. In order to enable homogeneous illumination of the device next to the work surface 2 in spite of this asymmetrical arrangement of the device, the reflector is designed as a free-form reflector 4, which deflects the emitted light of a half-space radiator 5 as a light source. With a suitable design of the free-form reflector 4, its emission cone 6 can be adapted to work surface 2 for uniform lighting.

Like the one in particular Fig. 5 As can be seen, the smallest distance 7 between the half-space radiator 5 and the free-form reflector 4 can increase along the direction of the greatest extent 8 from the far field 9 of the free-form reflector 4 to the near field 10 of the free-form reflector 4, whereby a uniform illumination of both the center of the work surface 2 and which is reached in the direction of the greatest extent of the work surface 8 upstream and downstream of the center. The far field 9 has a greater curvature than the near field 10, so that the radiation density increases in the direction of the area of the work surface 2 remote from the lamp 1. This means that a uniform illuminance can be achieved regardless of the distance between the area of the work surface 2 and the device according to the invention.

The half-space radiator 5 can be arranged in the area of the maximum curvature 11 of the free-form reflector 4, i.e. in an area vertically below the maximum curvature 11 , for example the center of the work surface 2, is directed.

To avoid sudden changes in the illuminance in the area of the accentuated points, the curvature of the free-form reflector 4 can decrease along the direction of the greatest extent 8 of the work surface 2 from the maximum curvature 11 to the edge areas of the free-form reflector 4. The example in the Fig. 5 The drawn radii of curvature make it clear that the decrease in the curvature and thus the increase in the radius of curvature of the far field 9 of the free-form reflector 4 is less than that of the near field 10. For example, the radii of curvature can be 49.48 mm (R1), 43.38 mm (R2), 44.1 mm (R3), 48.48 mm (R4), 65.85 mm (R5). Through the Figs. 4-8 a possible doubly asymmetrical shape of the free-form reflector 4 is illustrated.

Fig. 6 shows a section along the line VI-VI of FIG Fig. 4 , whereby the radii of curvature transversely to the direction of the greatest extent 8 of the working surface 2 are made clear. The radii of curvature are 52.85 (R6), 47.08 (R7), 52.55 (R8), 63.46 (R9), 72.13 (R10).

Fig. 7 shows a section along the line VII-VII of FIG Fig. 4 . The exemplary drawn radii of curvature are 39.4 mm (R11), 38.57 mm (R12), 37.69 mm (R13), 40.16 mm (R14), 47.01 mm (R15).

Fig. 8 shows a section along the line VIII-VIII of FIG Fig. 4 . The exemplary drawn radii of curvature are 49.66 mm (R16), 48.03 mm (R17), 47.75 mm (R18), 54.07 mm (R19), 75.38 mm (R20).

From the Figs. 6-8 it can be seen that the free-form reflector 4 also has a minimum radius of curvature R7, R13, R18 transversely to the direction of the greatest extent 8 of the working surface 2, from which the radii of curvature increase towards the reflector ends. The radii of curvature of the near field 10 in turn increase more strongly than the radii of curvature of the far field 9.

Like in the Fig. 1 is disclosed, the radiation cone 6 of the free-form reflector 4 is delimited by a vertical 12 and has an angle α in the direction of the longest extension 8 of the work surface 2, which is at least 36 °. The height h between the lamp 1 and the work surface can preferably be at least 50 cm and at most 170 cm. At the proposed angle α, complete illumination of the desired work area 2 can therefore be guaranteed despite the height variation of the lamp 1. In order to prevent a person on the work surface 2 from being dazzled, the angle β of the radiation cone 6 of the free-form reflector 4 delimited by the vertical 12 can be transverse to the direction of the longest extension 8 of the work surface 2 be at least 20 ° and at most 85 °. The vertical limits the radiation cone 6 so that a clear demarcation can be created between the work surface 2 to be illuminated and the surroundings not to be illuminated.

Fig. 3 shows the possibility of arranging several free-form reflectors 4 transversely to the direction of the greatest dimension 8. These free-form reflectors 4 are aligned in such a way that their respective radiation cones 6 are superimposed. As a result, the illuminance can be increased without producing an undesirable change in the lighting characteristics. A separate half-space radiator 5 can be assigned to each free-form reflector 4. In order to be able to make a slight adjustment of the lighting characteristics, a free-form reflector 4 can also be assigned several half-space radiators 5, which can be controlled independently of one another.

To illuminate one in the Fig. 1 For the double workstation 3 shown, it is recommended that the luminaire 1 comprise several free-form reflectors 4 arranged transversely to the direction of the greatest extent 8 of the work surface 2, which illuminate two adjacent, separate work surfaces 2, as shown in FIG Fig. 3 can be seen.

The free-form reflectors 4 assigned to the various work surfaces 2 can each be arranged on a carrier 13 which protrudes from a common base 14 transversely to the direction of the greatest extent 8 of the work surface 2. The base 14 can form a post 15 with a base 16, whereby the device according to the invention can be designed as a floor lamp. In contrast to the normal projection 18 of the lamp 1, the normal projection 17 of the base 16 overlaps the work surface. The normal projection17 of the base 16 can only be covered in sections.

So that the surroundings can be illuminated independently of the work area 2, the device according to FIG Fig. 2 have further half-space radiators 5, the radiation cone of which faces away from the work surface 2.

Claims (10)

Device with a lamp (1) arranged above a work surface with a lamp and a reflector arranged above the lamp and directed towards the work surface (2), characterized in that the lamp (1) is arranged without protrusion next to the work surface (2), that the illuminant is a half-space radiator (5) directed towards the reflector and that the reflector is a free-form reflector (4) designed to uniformly illuminate the work surface (2). Device according to Claim 1, characterized in that the smallest distance between the half-space radiator (5) and the free-form reflector (4) along the direction of the greatest extent (8) of the work surface (2) from a near field lying on the side of the work surface (2) (10) to an opposite far field (9) of the free-form reflector (4) decreases. Device according to Claim 1 or 2, characterized in that the half-space radiator (5) lies in the region of a maximum curvature (11) of the free-form reflector (4) and that the portion of the radiation cone (6) emitted by the maximum curvature (11) of the free-form reflector (4) is in Direction of the longest extension (8) of the work surface (2) is directed towards the center of the work surface (2). Device according to one of Claims 1 to 3, characterized in that the curvature of the free-form reflector (4) decreases along the direction of the greatest extent (8) of the working surface (2) from the maximum curvature (11) to the edge areas of the free-form reflector (4). Device according to one of claims 1 to 4, characterized in that the lamp (1) is arranged between 50 cm and 170 cm above the work surface (2) and that the angle (a) of the radiation cone (6 ) of the free-form reflector (4) is at least 36 ° in the direction of the longest extension (8) of the work surface (2). Device according to one of Claims 1 to 5, characterized in that the lamp (1) comprises several free-form reflectors (4) which are arranged transversely to the direction of the greatest extent (8) of the work surface (2) and have an overlapping radiation cone (6). Device according to one of Claims 1 to 6, characterized in that the angle (β) of the radiation cone (6) of the free-form reflector (4) delimited by the vertical (12b) transversely to the direction of the longest extension (8) of the work surface (2) is at least 20 ° and a maximum of 85 °. Device according to one of Claims 1 to 7, characterized in that the lamp (1) comprises several free-form reflectors (4) arranged transversely to the direction of the greatest extent (8) of the work surface (2), which two adjacent, separate work surfaces (2) illuminate. Device according to Claim 8, characterized in that, for each free-form reflector (4), optionally switchable groups of half-space radiators (5) assigned to a work surface (2) are provided, the emitted light per group of half-space radiators (5) via the free-form reflector (4) is directed to the assigned work surface (2). Device according to Claim 8 or 9, characterized in that the free-form reflectors (4) assigned to a work surface (2) are arranged on a carrier (13) which extends from a base (14) located between the work surfaces (2) in the direction of the one work surface (2) protrudes.

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