EP2587134B1 - Lamp - Google Patents

Description

The present application relates to a luminaire, in particular a sheet-like luminaire for use on a VDU workstation.

In particular, in the illumination of computer workstations, it is important to take effective anti-dazzle measures, since a person working on a screen can be dazzled not only by the light source itself but also by the light emitted by the light source and reflected by the screen surface. To avoid such glare already a number of glare-reducing measures have been proposed, which are anchored in various Entblendungs guidelines.

A trend in the lighting industry is to provide lights with LEDs as light sources, since LEDs have a high luminous efficacy compared to conventional light sources. Since the light in the semiconductor of the LED is generated from a small surface area, today's highly efficient LEDs suitable for workplace illumination have a very high luminance (eg 50 x 10 ^ 6 cd / m 2) so that effective antiglare measures are particularly indicated are. Due to the high brightness of the LEDs, the glare is enhanced and reflections occur more frequently on the screen surface.

From the publication DE 10 2006 016 218 A1 a luminaire is known which has a plurality of illumination sources in the form of LEDs. Furthermore, a light-scattering, plate-shaped body is provided on the emission side of the illumination sources, which has openings which expand to the emission side. Part of the light emitted by the LEDs passes through the openings of the body. A second part of the light emitted by the LEDs hits unimpeded on the surface of the body and becomes in the plate-shaped Body initiated. At least a part of the light radiation introduced into the body is then diffused again as so-called secondary radiation from the plate-shaped body. Although only a portion of the light emitted by the LEDs penetrates into the plate-shaped body and is diffused by the same again, it is found that this diffuse secondary radiation is so bright that it can be a person working under such a lamp directly or indirectly via reflections on the screen unpleasant dazzles.

From the publication GB 2479142 a luminaire is known, which has a plurality of LEDs as light sources, a Entblendungsraster and a cup-shaped optical element.

The object of the present invention is therefore to provide a luminaire which is effectively blinding even when using high-efficiency LEDs with high luminance.

• eine Vielzahl von LEDs als Lichtquellen vorsieht,
• ein Entblendungsraster aufweisend eine Vielzahl von nebeneinander angeordneten, durchgehenden Entblendungskanälen und eine Vielzahl von die Entblendungskanäle voneinander trennenden Stegen, wobei jeder Entblendungskanal ein erstes Ende und ein dem ersten Ende gegenüber liegendes zweites Ende hat, und
• ein Lichtlenkpanel aufweisend eine Vielzahl von nebeneinander angeordneten, becherförmigen lichtleitenden Elementen, wobei jedes lichtleitende Element jeweils einen durchgehenden Lichtlenkkanal vorsieht, der ein erstes Ende und ein dem ersten Ende gegenüber liegendes zweites Ende hat.

The above object is achieved by a luminaire which

• provides a plurality of LEDs as light sources,
• a blanking grid comprising a plurality of side-by-side continuous blanking channels and a plurality of webs separating the blanking channels, each blanking channel having a first end and a second end opposite the first end, and
• a light guide panel comprising a plurality of juxtaposed cup-shaped photoconductive elements, each photoconductive element each providing a continuous light-directing channel having a first end and a second end opposite the first end.

In this case, the anti-dazzle channels, the LEDs and the light-guiding channels are arranged in such a way that at least one LED is arranged at the first end of the light guide channel of each light-conducting element and one light-conducting element is provided in each anti-dazzle channel in the region of the first end of the light guide channel. The inner surface of each light guide channel is formed to receive the emitted light of each of the first 26 October 2012 G 102 P 9 EP End of the light guide channel arranged at least one LED almost completely reflected and directs in the direction of the second end of the respective Entblendungskanals that surrounding the respectively associated Entblendungskanal webs are illuminated only weak.

Accordingly, unlike the prior art, the luminaire according to the invention has two components, namely the light-conducting elements of the light-guiding panel and the glare control channels of the glare screening, which take over the light guidance or glare suppression. The division of tasks by light-guiding panel and glare screening means a much greater effort in terms of material and costs compared to the conventional solution. However, this effort is worthwhile, as achieved by the structure according to the invention a significant improvement in glare and thus a more pleasant for the user light is generated.

The better glare reduction is achieved in that the light-conducting element is arranged at the first end of the respective anti-dazzle channel. Since the light-conducting elements almost completely reflect the light passing through the respective light-guiding channel, no light from the LED (s) is incident on the surrounding webs in the region of the first end of the anti-dazzle channel. Only at the second end of the anti-dazzle channel, the surrounding webs are illuminated substantially by stray light, which is mainly formed at the second end of the Lichtlenkkanals. The greatest part of the light emitted by the LEDs is directed by the light-guiding channels so that the light passes through the glare-out channels without any interaction with the glare control grid. Since hardly any light radiation from the LEDs enters into the glare screening, it can also emit only little secondary radiation, so that the glare reduction grid appears pleasantly dark to the viewer looking in the direction of the light and optimum glare suppression is effected. Furthermore, by the light guide channel used in the glare channel, which has at its second end an opening with a smaller diameter than the glare channel in this area, the direct insight into the light source of the lamp is additionally limited, so that even at a glare angle of 60 ° an effective glare reduction is achieved.

By interleaving the light guide channels and the Entblendungskanäle also the walls of the Entblendungskanäle separating webs can be formed almost parallel to the vertical, which further reduces the glare. Furthermore, this minimizes the area of the glare reduction grid that is visible to the viewer from below, which likewise leads to a reduction in glare. The inclusion of the Lichtlenkkanäle and the Entblendungskanäle also has the advantage that the overall height of the lamp compared to the conventional solution is not increased and the lamp further has a flat structure.

Overall, therefore, precise control and limitation of the luminance of the light emitted by the LEDs for effective glare while maintaining optimum light control and optimum efficiency is achieved by the interleaving of the light guide channels and the Entblendungskanäle.

In the present invention, each of the first end of the anti-dazzle channels and the first end of the light guide channels are located approximately at the level of the top of the arranged on a circuit board LEDs. The second end of the light-guiding channels and the second end of the anti-dazzle channels are each located on the opposite emitting side of the LEDs, wherein the height of the light-guiding channels in the emission direction is less than the height of the anti-dazzle channels. Depending on a light guide channel is arranged in a Entblendungskanal.

In each case either an LED or a group of closely arranged LEDs, for example three or four LEDs, may be provided for a glare channel and a light-guiding channel. The use of an LED group as a light source is particularly advantageous if the combination of the spectral ranges of the LEDs of a group is to achieve a particularly balanced and pleasant light spectrum for the user.

The glare grid can be transparent or opaque. For a higher opacity, the anti-dazzle screen may be colored. In the former case, the luminaire appears brighter outside the viewing angle than when coloring the anti-dazzle screen. However, even if the Entblendungsraster has a comparatively high degree of transparency, the Entblendungsraster for reasons described above only slightly brightened because it, except for stray light, illuminated by the LEDs only slightly.

In a preferred embodiment, the inner surface of each light-guiding channel is formed to be at least 75%, preferably at least 85% reflective, particularly preferably white or chrome-colored. As a result, an optimal light steering is achieved and avoided in the area of the light guide channel, the illumination of the webs of Entblendungsrasters. The described reflection behavior on the inner surface of the light guide channels also has a decisive positive influence on the efficiency of the luminaire.

Particularly low secondary radiation, ie light radiation passing through the anti-dazzle screen, is generated by the anti-glare grid when the light from the LEDs is guided by the light-guiding channels such that at most a proportion of 10% of the primary radiation, preferably at most a proportion of 5% of the primary radiation the webs surrounding the Entblendungskanal falls. Here, primary radiation means the light of the LEDs, either comes directly from the respective LED or was reflected on the surface of the light guide channel.

As already stated above, it is advantageous if only one front section of the webs of the anti-dazzle screen is illuminated, which lies on the second end of the respective anti-dazzle channel. At the front portion of the webs of the anti-dazzle screen, they have only a small volume, so that for this reason as a whole the luminance of the secondary radiation in the region of the anti-glare screen is reduced.

In a further preferred embodiment, the at least one LED and corresponding to the first end of each light guide channel is arranged adjacent to the longitudinal axis of the respectively associated anti-dazzle channel. Alternatively or additionally, the longitudinal axis of each light guide channel can extend inclined to the longitudinal axis of the respectively associated anti-dazzle channel. The angle of inclination of the longitudinal axes to each other is at least 5 °, preferably at least 15 °. Due to the off-center position of the LED with respect to the anti-dazzle channel and / or the inclination of the longitudinal axis of the light guide channel to Entblendungskanal longitudinal axis, there is a shift of the light center of the LED axis out, resulting in a broader and more homogeneous distribution of the light emitted by the LEDs , This results in a broader and more uniform illumination of the workplace illuminated with the luminaire according to the invention.

A further measure which serves to illuminate the workplace further and more homogeneously is that the glare channels and, correspondingly, the light-guiding channels arranged therein are arranged in an even number of n (for example n = 4) rows arranged side by side (in the example: 4 rows). are provided. Here, the light steering channels of the n / 2 rows (in the example: 2 rows) have a first side (eg, the left side) with respect to a center line a longitudinal axis inclined to the longitudinal axis of the respectively associated anti-dazzle channel after the first side (eg to the left) and the second side (eg the right-hand) light-guiding channels to n / 2 rows lying in relation to the center line (in the example: 2 rows) a to the second side (eg to the right) to the longitudinal axis of the respective associated Entblendungskanals inclined longitudinal axis.

The glare reduction is particularly effective, in particular, in that the height of the light-guiding channels is approximately half the height of the respectively associated glare-reducing channels. As a result, the light-guiding channels extend far into the respectively associated anti-dazzle channel and, in addition, due to their smaller diameter, as shown above, reduce the view into the respective light source.

It is also advantageous if the ratio between the wall distance at the second end of the light guide channel and the web distance at the second end of the associated anti-dazzle channel is between 0.5 and 0.6. The smaller the second opening arranged in the emission direction at the second end of the light guide channel, the greater the glare angle which is important for visual comfort. However, too small an opening at the second end of the light guide channel limits the homogeneity of the light generated by the lamp and the light emitted by the LEDs is too focused. In this case, the distance between the opposite wall centers of the light guide channel at the second end and below the web spacing means the distance of the opposing web centers at the second end of the delamination channels.

By using a high number of at least 180 LEDs for a luminaire, preferably at least 230 LEDs, more preferably at least 480 LEDs reduces the problem of multiple shading beyond recognition.

Other features, advantages and applications of the invention will become apparent from the following description of an embodiment of a lamp according to the invention and the figures. All described and / or illustrated features alone or in any combination form the subject matter of the present invention, also independent of their summary in the claims or their back references.

Fig.1

eine perspektivische Ansicht einer erfindungsgemäßen Leuchte von schräg unten,

Fig. 2

einen vergrößerten Ausschnitt der in Fig. 1 dargestellten Leuchte,

Fig. 3

eine Ansicht der in Fig. 1 dargestellten Leuchte von unten,

Fig. 4a und 4b

jeweils den gleichen Querschnitt durch die für die Lichterzeugung wesentlichen Elemente der Leuchte gemäß Fig. 1 entlang der Richtung A-A (siehe Fig. 3) ohne und mit eingezeichneten Randstrahlen a, b und

Fig. 5a und 5b

jeweils den gleichen Längsschnitt durch die für die Lichterzeugung wesentlichen Elemente der Leuchte gemäß Fig. 1 entlang der Richtung B-B (siehe Fig. 3) ohne und mit eingezeichneten Randstrahlen c, d.

They show schematically:

Fig.1

a perspective view of a lamp according to the invention obliquely from below,

Fig. 2

an enlarged section of the in Fig. 1 illustrated luminaire,

Fig. 3

a view of in Fig. 1 shown light from below,

Fig. 4a and 4b

in each case the same cross-section through the elements of the luminaire which are essential for the generation of light according to Fig. 1 along the direction AA (see Fig. 3 ) without and with marked marginal rays a, b and

Fig. 5a and 5b

in each case the same longitudinal section through the elements essential for the light generation of the luminaire according to Fig. 1 along the direction BB (see Fig. 3 ) without and with marked marginal rays c, d.

The in the Figures 1 and 2 partial illustrated office pendant lamp has a housing 1. In the lower region of the housing 1, two printed circuit boards 3 with a plurality of LEDs 5, a glare screening 10 and a light guide panel 20 are provided. The printed circuit boards 3 are fastened to the housing 1 by means of a holding plate, not shown. In the emission direction over the printed circuit boards 3, the light guide panel 20 is arranged, which is inserted into the glare reduction 10 and is held by the glare barrier 10. This is attached by means of the Verblendungsraster 10 attached latching lugs 11 and projections 12 on the housing 1.

The luminaire according to the invention has four rows of adjacent LEDs 5, with two rows of LEDs 5 each being formed by a printed circuit board 3. Each LED 5 is assigned a light-conducting element 21 of the light-guiding panel 20 and a glare duct 13 of the anti-dazzle screen 10. Accordingly, the Entblendungsraster includes four rows of adjacent Verblendungskanälen 13, each having on its emission side a symmetrical, approximately square opening and in the direction of light easily, for example in the form of a parabola expand. The Entblendungskanäle 13 are separated by the wall of the Entblendungskänale 13 forming webs 14 from each other. The respective outer anti-dazzle channels 13 are also bounded on the outside by applied to the housing 1 Entblendungsraster walls 15.

Each cup-shaped light-conducting element 21 of the light-guiding panel 20 in each case has a continuous light-guiding channel 22, which likewise widens in the emission direction. Analogous to the anti-dazzle channels 13, the light guide panel 20 forms four rows of adjacent light-conducting elements 21.

The light guide panel 20 is arranged such that the first end 26 of the light guide channel 22 is approximately in the region of the top of the LEDs 5. Further, the light guide panel is inserted into the anti-dazzle grid 10, that the light-conducting element 21 is disposed at the first end 16 of the anti-dazzle channel 13, wherein the first end 16 of the anti-dazzle channel 13 and the first end 26 of the light guide channel 22 at about a height in the region of the top the LEDs 5 are located.

The inner surface 27 of the light guide channel 22 is e.g. white glossy or chrome-plated, so that it reflects the incident light of the respective LED 5 at least 75%. The light guide panel 20 consists for example of ASA plastic (acrylic ester-styrene-acrylonitrile) and may have a chromium layer in the case of a chromed inner surface 27 of the light guide channels 22.

The anti-dazzle screen 10, in particular its webs 14 or walls 15, for example, consist of a transparent material, e.g. PC plastic (polycarbonate).

The inner surface 27 of the light guide channel 22 is formed as an asymmetric free-form surface, which shifts the light center, in particular in the transverse direction of the lamp from the axis of the LED 5 addition. This is special FIG. 4b can be seen in which the marginal rays a, b of the outgoing light from the LED 5 are located. It can be seen that the light of the two rows of LEDs lying to the left of a center line is directed to the left outside, while the light of the LEDs 5 of the two rows to the right of the center line is directed to the right outside. This results in a wide illumination of the workplace.

Furthermore, each LED 5 is arranged next to the longitudinal axis 17 of the respective anti-dazzle channel 13, namely in the two left rows of FIGS. 4a and 4b right next to the longitudinal axis 17 and at the two rows of LEDs 5 to the right of the center line to the left of the longitudinal axis 17 of the respective anti-dazzle channel 13.

From the course of the marginal rays a, b of in FIG. 4b shown cross section through the lamp according to the invention shows that only in the respective outward direction (edge beam b) light from the LED 5 directly on a front end of the webs 14 and walls 15 falls. The inward edge beam a does not strike a web 14 or a wall 15.

Of the FIG. 5b It can be seen that on the other hand, the inner surface 27 of the light guide channel 22 is formed symmetrically in the longitudinal direction of the lamp, since the marginal rays c, d are deflected about the same extent.

From the course of the marginal rays c, d in the FIGS. 5a and 5b shown longitudinal section through the lamp according to the invention can be seen that in addition to the always existing scattered radiation, which is mainly formed at the second end 28 of the Lichtlenkkanals 22, in the longitudinal direction no direct light from the LED 5 on the webs 14 and walls 15 of the Entblendungsrasters 10 falls.

Due to the shape of the inner surface 27 of the Lichtlenkkanals 22 falls at most a share of 10% of the primary radiation, especially in the direction transverse to the luminaire and to the outside (edge beams b) on the respective webs 14 and walls 15 of the Entblendungsrasters 10th

In the in the FIGS. 5a and 5b In the embodiment shown, only one LED 5 is assigned to one light-guiding channel 22 and one screening channel 13. Alternatively, a light guide channel 22 and a glare channel 13 are each a group of LEDs 5, which are arranged directly next to each other, may be provided.

In FIG. 4a is further shown that the longitudinal axis 29 of the light guide channel 22 extends at an angle α of at least 5 °, preferably at least 15 ° inclined to the longitudinal axis 17 of the anti-dazzle channel 13. Here, the longitudinal axes 29 of the two left rows of Lichtlenkkanäle 22 are inclined by the angle α to the left to the longitudinal axis 17 of the Entblendungskanals 13, while the two right rows of Lichtlenkkanäle 22 by the angle α to the right with respect to the longitudinal axis 17 of the Entblendungskanals 13 are inclined.

The height h of the light-guiding element 21 or the light-guiding channel 22 is for example about 8.5 mm and the height H of the anti-glare duct 13 is e.g. about 16 mm. Consequently, the height h of the light guide channel 22 is more than half the height H of the associated anti-dazzle channel thirteenth

The wall distance w1 at the second end 28 of the light guide channel 22 is approximately 12 mm in the transverse direction, for example, and the web distance W1 of the anti-dazzle channel 13 at its second end 18 is in the same direction e.g. about 22 mm. The ratio between the wall distance w1 and the web distance W1 is therefore approximately 0.55 in the transverse direction.

In the in the FIGS. 5a and 5b In the longitudinal direction shown, the ratio of wall distance w2 to web distance W2 is about 0.56, where w2 is about 14 mm and W2 is about 25 mm.

Overall, in the luminaire according to the invention described above and illustrated in the figures by the two-part design (light guide panel 20 and glare bar 10) of the components for light control and glare and by the interleaving of these components into each other effective glare control achieved with a glare angle of 60 ° to 65 ° while maintaining optimal light control and high efficiency.

LIST OF REFERENCE NUMBERS

1

casing

3

circuit board

5

LED

10

anti-glare louvre

11

locking lug

12

head Start

13

Entblendungskanal

14

web

15

wall

16

first end of the anti-dazzle channel 13

17

Longitudinal axis of the anti-dazzle channel 13

18

second end of the anti-dazzle channel 13

20

Light control panel

21

photoconductive element

22

Light-guiding channel

26

first end of the light guide channel 22

27

inner surface of the light guide channel 22nd

28

second end of the light guide channel 22nd

29

Longitudinal axis of the light guide channel 22nd

a, b, c, d

marginal rays

H

Height of the light guide channel 22

H

Height of the glare channel 13

w1, W1

Wall distance of the photoconductive element 21st

W1, W2

web spacing

Claims (11)

1. Light fixture, in particular an area light fixture to illuminate a VDU workstation

   • with a multitude of LEDs (5) as light sources,

   • with an anti-glare grid (10) comprising a multitude of full-length anti-glare channels (13) arranged side by side and a multitude of webs (14) separating the anti-glare channels (13), whereby every anti-glare channel has a first end (16) and opposite the first end a second end (18), and

   • with a light-guiding panel (20) comprising a multitude of cup-shaped light-guiding elements (21), wherein each light-guiding element provides a light-guiding channel (22) going through which has a first end (26) and opposite the first end a second end (28),
   wherein respectively at least one LED (5) is located at the first end (26) of the light-guiding channel (22) of each light-guiding element (21) and respectively one light-guiding element (21) is located in each anti-glare channel (13) in the section of the first end (16) of the anti-glare channel (13), whereby the inner surface (27) of each light-guiding channel (22) is designed so that it almost completely reflects the light emitted by the at least one LED (5) respectively located at the first end (26) of the light-guiding channel (22) and thereby directs it towards the second end (18) of the respective anti-glare channel (13) so that the webs (14) surrounding the respectively corresponding anti-glare channel (13) are only weakly illuminated.
2. Light fixture according to claim 1, characterized in that the inner surface (27) of every light-guiding channel (22) is designed to be at least 75% reflective, preferably white or chrome-coloured.
3. Light fixture according to one of the preceding claims, characterized in that the amount of the primary emission impinging on the webs (14) surrounding the anti-glare channels (13) does not exceed 10%.
4. Light fixture according to one of the preceding claims, characterized in that respectively only a section at the front of the webs (14) of the anti-glare grid (10) which is located at the second end (18) of the respective anti-glare channel (13) is illuminated.
5. Light fixture according to one of the preceding claims, characterized in that the material of the webs (14) of the anti-glare channel (13) is transparent or opaque.
6. Light fixture according to one of the preceding claims, characterized in that the at least one LED (5) is located next to the longitudinal axis (17) of the respectively corresponding anti-glare channel (13).
7. Light fixture according to one of the preceding claims, characterized in that the longitudinal axis (29) of every light-guiding channel (22) inclines towards the longitudinal axis of the respectively corresponding anti-glare channel (13).
8. Light fixture according to one of the preceding claims, characterized in that the anti-glare channels (13) and accordingly the light-guiding channels (22) therein are provided in an even quantity of n rows arranged side by side, wherein the light-guiding channels (22) of the n/2 rows on a first side relative to a centre line have a longitudinal axis (29) which inclines to the first side towards the longitudinal axis (17) of the respectively corresponding anti-glare channel (13) and the light-guiding channels (22) of the n/2 rows on the second side relative to the centre line have a longitudinal axis (29) which inclines to the second side towards the longitudinal axis (17) of the respectively corresponding anti-glare channel (13).
9. Light fixture according to one of the preceding claims, characterized in that the height (h) of the light-guiding channel (22) is approximately half the height (H) of the respectively corresponding anti-glare channel (13).
10. Light fixture according to one of the preceding claims, characterized in that the ratio of the wall distance (w1, w2) at the second end (28) of the light-guiding channel (22) and the web distance (W1, W2) at the second end (18) of the corresponding anti-glare channel (13) is between 0.5 and 0.6.
11. Light fixture according to one of the preceding claims, characterized in that the light fixture features at least 180 LEDs (5).

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