EP1586818B1 - Luminaire - Google Patents

Abstract

Lighting (1) with part shining directly from its underside has a light source fitted lengthwise to the light housing (3) as well as a prism cover (4) under the light source (2). The prism cover is fitted with a prismatic structure lengthwise to the light source. A second prism cover (5) with a prism cover fitted obliquely to the first prismatic structure which has been fitted lengthwise to the light source. The second prism cover covers the first at least partly.

Description

The present invention relates to a luminaire with a light component radiated directly toward the underside and an indirect light component radiated toward the upper side, comprising at least one luminous means aligned in the longitudinal direction of the housing and at least one prism cover below the luminous means.

Luminaires in which prism covers are used which are arranged below the luminous means have been known for some time from the prior art. The use of a kind of prism cover for the downwardly radiated light component in a so-called direct / indirect light is also known and is for example in the utility model DE 299 03 298 U1 described. This is a comparatively flat luminaire, which radiates an indirect light component, which contributes to the general brightening of the room, as a suspension lamp suspended from the ceiling. With the light component radiated directly from the luminaire to the underside, it is important in the case of such a suspended luminaire that good glare reduction be provided. A standard luminaire for illuminating, for example, office space should have a glare of those light components that emerge at angles from the luminaire, which are shallower than 65 ° to the vertical, since such flat emitted light components can dazzle people working on computer screens. In the light known from the aforementioned publication of the fluorescent lamps immediately downwards exiting light component is directed by a light grid. Alternatively It is also possible to use a prism structure for a targeted and glare-free light distribution. Also provided are plate-shaped light distribution elements with hollow chambers which scatter the light. These light distribution elements with scattering structure are used in the areas adjacent to the area in which the fluorescent lamps are located.

It is known to use in luminaires with bulbs in the form of fluorescent lamps for light guidance "prism covers" with extending in a direction parallel spaced ribs having a kind of sawtooth or triangular profile on the side facing away from the light source. By using such a prism cover can be achieved by targeted refraction of the emitted light rays from the lamp an improved anti-glare characteristic. Due to the course of the ribs or the sawtooth profile or triangular profile due to the glare is achieved only in certain viewing directions. Looking from directions transverse to the main direction, in which the glare takes place, in the lamp, the glare is not sufficient.

The US 4,233,651 describes a work lamp, with a first, the fluorescent tube in the longitudinal direction covering prism plate with downward prisms, and a second, arranged underneath prism plate with upwardly and transversely to the longitudinal direction arranged priming plate only half the length. The lower prism plate does not limit the angle of the downwardly emitted light.

From the DE 19961493 A1 is a so-called light guide plate, in which the bulbs are arranged "hidden" from one of a box-shaped, horizontally extended housing and the light over the extension of the housing transversely to the longitudinal extent of the bulb coupled by multiple reflection with corresponding reflection losses and is distributed. Since the light emitted by the illuminant incident on the light exit surface at an extremely flat angle, this is coupled out by crossed prism plates.

Based on this prior art, the object of the present invention is to provide a luminaire of the type mentioned, which has a further improved Entblendungscharakteristik at the same time high luminous efficacy with respect to the downwardly emerging from the lamp light component.

The solution to this problem provides a lamp according to the invention of the type mentioned above with the characterizing features of the main claim.

According to the invention, it is provided that at least one first prism cover is provided with a prism structure oriented essentially in the longitudinal direction of the luminous means, and at least one second prism cover with a prism structure aligned substantially transversely to the longitudinal direction of the luminous means, wherein the second prism cover covers the first prism cover at least in regions.

Through the use of two prism covers it can be achieved that the first prism cover effects effective glare suppression in a main viewing direction, and that the second prism cover achieves an effective glare reduction also in directions which are substantially transverse to the aforementioned main viewing direction.

In the area that is relevant for the light emission downwards, the two prismatic covers can cover or overlap predominantly or preferably almost completely. Accordingly, the first prism cover is preferably arranged at a suitable distance below the luminous means and the second prism cover can be arranged at a greater or lesser distance again below this first prism cover. If a flat construction of the luminaire is desired, the second lower prism cover is preferably arranged comparatively close to the first upper prism cover.

The first prism cover preferably has prism structures extending on the underside and preferably in the longitudinal direction of the luminous means. These prism structures are preferably designed such that a tooth profile results in the cross section of the prism cover, that is to say thus transversely to the longitudinal direction of the prism structures. Preferably, it is a sawtooth or triangular tooth profile, wherein a symmetrical tooth profile shape is particularly preferred. Preferably, the prism edges span an angle α (see Fig. 2 ) from 80 to 100 °, ie the downwardly facing priming surfaces are inclined by 40 to 50 ° to the horizontal central plane of the lamp, so that substantially orthogonal to the Reflected light is deflected by two reflections on the prism surfaces in the upper half-space prism cover, so that the luminance of the prism plate is reduced immediately below the light source.

More preferably prism edges are flattened, so that a trapezoidal structure results in cross-section transverse to the prism structure, so that the orthogonally incident light is not completely deflected into the upper half-space. Due to the extent of the flattening, the proportion of the light not deflected into the upper half-space can be adjusted.

Further preferably, the flattening is rounded, preferably in the form of a circular arc (in the cross-sectional view, radius R in FIG Fig. 2 ) so that the passing light is fanned out. The prism structure may have a more or less strong tread depth. It is essential that the tread depth is not too large, otherwise a stripe structure can form below the luminaire. With a tread depth of 0.5 to 2 mm (H in Fig. 2 ), preferably less than 1.5 mm, it comes at a distance of not more than 10 cm from the lamp base no longer to form such strip structures.

The first, preferably upper prism cover may preferably have a substantially flat plate shape.

The lower, preferably second prismatic cover may preferably have a convexly arched basic shape as seen from the underside of the luminaire, preferably viewed convexly in the transverse direction of the luminaire, that is transversely to the longitudinal orientation of the luminous means, wherein elongated fluorescent lamps are generally used as the luminous means. The radius of curvature of the convexly curved base body may be 6 to 10 times the diameter of the fluorescent tube, wherein the distance between the longitudinal central axis of the fluorescent tube from the longitudinal center line of the curved base body preferably about 1.7 to 2.5 times the diameter of the fluorescent tube corresponds.

Preferably, the side longitudinal edges of the first and second priming cover touch or have only a small distance.

The prism structure of the second prism cover preferably has a larger prism angle. Preferably, the angle between the prism surfaces 110 to 130 ° (angle β in Fig. 3 ), particularly preferably 115 to 125 °, be, preferably without flattening or rounding of the prism edges.

The prism covers are made of highly transparent material such as glass or plastics, such as acrylic glass.

The longitudinal extent of the luminaire corresponds to the length of the fluorescent tube plus the extension of the terminating elements required at both ends. The horizontal transverse extent can be 5 to 12 times the lamp diameter.

The luminaire according to the invention is preferably a pendant luminaire, but in principle a combination of the prism covers according to the present invention is also suitable, for example, in the case of a floor lamp. The inventively preferred pendant lamp is open above the bulb, so that a part of the light emitted by the bulb, including the upwardly deflected by the first prism cover light shines against the ceiling and from there contributes as an indirect diffused light for room illumination.

The lamp according to the invention can also be a surface or recessed luminaire with lateral Lichtverteilkammern, the lateral vertical, the fluorescent tube facing transparent, diffusely scattering light entry surfaces, an upper designed as a reflector cover and lower, converging towards the reflector converging transparent, diffusely scattering . have curved light emitting surfaces. In particular, when using the invention in such recessed or surface mounted lights, it is advantageous for aesthetic reasons to use the second prism cover in the basic form of a flat plate. This results in that the two prism covers can be close to each other, a particularly low height of the lamp.

Furthermore, it may be advantageous to form both prismatic covers with a curved basic structure, in particular with a curvature in the same direction. If the first prism cover is formed with a planar upper side and a convexly curved underside, the prism structure being rotated with the radius of curvature, a particularly good emission angle limitation of the light emitted by the illuminant with a flat emission angle can be achieved.

As illuminants are preferably used in a luminaire according to the invention fluorescent lamps, wherein one, two or more fluorescent lamps can be used, preferably in the longitudinal direction of the luminaire extending and arranged parallel to each other. In particular, in the case of luminaires having two or more fluorescent lamps, it may be advantageous to attenuate the light radiated downward in the direction of the prismatic covers by a partially-mirrored film arranged above the first prismatic cover.

Furthermore, it is possible to provide asymmetrically radiating luminaires by asymmetrical design of the prism structure, for example to equip luminaires which are installed in the vicinity of room walls with an asymmetrically directed downward and to the room wall lighting profile, since it does not depend on glare-free wall if there are no people here.

Fig.1

einen senkrechten Querschnitt zur Längsachse des Leuchtmittels einer erfindungsgemäßen Pendelleuchte;

Fig. 2

eine Vergrößerung des Ausschnitts A aus Fig. 1 zur Darstellung einer besonders bevorzugten Prismenstruktur der ersten Prismenabdeckung; und

Fig. 3

eine Vergrößerung des Querschnitts B-B der Fig. 1 zur Verdeutlichung der Prismenstruktur der zweiten Prismenabdeckung.

The invention will be described below with reference to the schematic figures explained in more detail. In these show:

Fig.1

a vertical cross section to the longitudinal axis of the luminous means of a pendant lamp according to the invention;

Fig. 2

an enlargement of the section A from Fig. 1 to illustrate a particularly preferred prism structure of the first prism cover; and

Fig. 3

an enlargement of the cross section BB of Fig. 1 to clarify the prism structure of the second prism cover.

The luminaire 1 consists essentially of a fluorescent lamp 2, a luminaire housing 3, a first primer cover 4 and a second prism cover 5.

The fluorescent lamp 2 mounted on a suspension, not shown below the ceiling lamp 1 radiates on the one hand directly upwards against the ceiling for indirect diffuse room lighting.

The radiated down at a large opening angle to the first prism cover 4 light is deflected by the prism diffraction on the one hand to a narrower angle, preferably preferably less than 65 ° to the vertical central plane and partially deflected upward, with this first prism cover 4 substantially no constriction the emission angle in the longitudinal direction of the lamp 1 takes place.

According to the invention, a second, preferably convexly curved, prismatic cover 5 is provided below the first priming cover 4, the prism structure of which is formed transversely to the prismatic structure of the first cover 4 and which therefore causes a narrowing of the emission angle in the longitudinal direction of the luminaire.

How out Fig. 1 and 2 can be seen, the first prism cover 4 has a flat top and a bottom with a prismatic structure. The prism structure consists of parallel to the light bulb elongated prism surfaces which together form an angle α of 40 to 50 ° and the prime edges are flattened by a rounding with the radius R, which may be, for example, 0.2 to 0.7 mm. The profile depth H of the prisms can be 0.5 to 1.5 mm, for example, the extent L of the flat flank surfaces of the prisms can be 0.2 to 1.2 mm. The second prism cover according to Fig. 3 an angle β between the inwardly directed prism flanks of 110 to 125 °.

LIST OF REFERENCE NUMBERS

1

lamp

2

Fluorescent Lamp

3

luminaire housing

4

first prism cover

5

second prism cover

Claims (12)

1. Luminaire having a light portion which is radiated directly towards the lower side,
   comprising at least one fluorescent tube (2) and at least a first prism cover (4)
   which is arranged below the fluorescent tube and which has a prism structure which is orientated at the lower side substantially in the longitudinal direction of the fluorescent tube,
   and at least a second prism cover (5),
   with the second prism cover being arranged below the first prism cover with a prism structure which is orientated transversely relative to the longitudinal axis of the fluorescent tube,
   characterised in that the prism sides of the prism structure of the first cover have an angle (α) of from 80 to 100° and in that the at least second prism cover covers the first prism cover,
   the prism sides of the prism structure of the second cover having an angle (β) which is greater than the prism side angle of the first prism cover.
2. Luminaire according to claim 1, wherein the prism sides of the second prism cover form an angle (β) of from 110 to 130°.
3. Luminaire according to claim 1 or claim 2, wherein the first prism cover (4) has a substantially planar plate shape.
4. Luminaire according to any one of claims 1 to 3, wherein the prism structure of the first prism cover (4) is constructed in cross-section as a triangular profile with rounded edges.
5. Luminaire according to any one of claims 1 to 4, wherein the second prism cover (5), when viewed in the transverse direction of the luminaire from the lower side of the luminaire, has a basic shape which is curved in a convex manner.
6. Luminaire according to any one of claims 1 to 5, wherein the prism structure of the second prism cover (5) is in the form of a tooth profile which extends in the direction which is transverse relative to the longitudinal axis of the fluorescent tube.
7. Luminaire according to any one of claims 1 to 6, wherein the prism structure of the second prism cover (5) is a triangular tooth profile.
8. Luminaire according to any one of claims 1 to 7, wherein the prism structure of the first prism cover (4) and/or the prism structure of the second prism cover (5) is a symmetrical triangular profile.
9. Luminaire according to any one of claims 1 to 8, wherein it is a suspended luminaire having an upwardly radiating light portion.
10. Luminaire according to any one of claims 1 to 7, wherein it is constructed with fluorescent lamps so as to have one or two lamps.
11. Luminaire according to any one of claims 1 to 10, characterised in that the luminaire housing (3) is substantially open towards the upper side of the luminaire.
12. Luminaire according to any one of claims 1 to 11, wherein the first prism cover (4) is located, in the region of the longitudinal edges thereof, on the longitudinal edge regions of the second lower prism cover (5) which is curved in a convex manner or is arranged thereabove with only very little spacing.

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