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(11) | EP 0 643 259 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
A cross lamella for a light box Querlamelle für Leuchtenkasten Lamelle transversale pour caisson lumineux |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] The invention relates to a light box, in which a plurality of cross lamellae are disposed at least substantially parallel to each other under (a) light source(s), transversely to the longitudinal direction of said box, and whereby a cross lamella is bounded by lateral boundary surfaces sloping upwards from the lower boundary edge of the lamella in a direction away from each other, said lateral boundary surfaces being interconnected near their upper edges by an upper boundary surface, in such a manner that the cross lamella is substantially triangular, seen in sectional view and whereby one lateral boundary surface extends upwards from the lower boundary edge of the cross lamella along a greater distance than does the other lateral boundary surface and said cross lamellae are arranged mirror-symmetrically relative to the centre plane of the light box transverse to the longitudinal axis of the light box.
[0002] WO 90/112245 shows such a structure wherein the lamella or transverse fins are arranged as pairs of single fins, with a mirror symmetrical design about a center plane from each pair.
[0003] According the invention the cross lamellae are arranged with their upper boundary surfaces sloping downward in the direction towards said centre plane. In using the structure according the invention there will be obtained an even distribution of the emitted light.
[0004] As a result of the different angles of incidence and exit of the light from the light source(s) achieved by altering the position of the boundary surface, also the occurrence of objectionable light reflections appears to be considerably less than is the case with the constructions that have been usual so far. A further reduction of the width of the upper boundary surface, seen in the longitudinal direction of the light box, so that an even better utitilization of the light from the light source(s) may be obtained, can be achieved when the connecting lines between the side edges of the upper boundary surface and the upper edges of the lateral boundary surfaces are both curved, whereby the centre of curvature of each connecting line is located at the side of the respective connecting line remote from the other connecting line.
[0005] The invention will be explained in more detail hereafter with reference to embodiments of the construction according to the invention diagrammatically illustrated in the accompanying Figures.
[0007] Figure 2 is a smaller-scale cross-sectional view of a number of cross lamellae arranged in side-by-side relationship.
[0009] Figure 4 is a front view of another embodiment of a cross lamella according to the invention.
[0010] Figure 5 is a front view of a third embodiment of a cross lamella according to the invention.
[0013] The description below is based on a light box comprising one or more light sources fitted therein, in particular (a) TL-tube(s), whereby the light box, more in particular said TL-tube(s), extend(s) horizontally, although also other arrangements of such a light box will be conceivable, of course.
[0014] As is diagrammatically indicated in Figure 3, a number of cross lamellae 2 extending parallel to each other are thereby provided under the light source(s) (not shown) within the light box.
[0015] Each cross lamella has two lateral boundary surfaces 4 and 5, which extend upwards from a lower boundary edge 3 of the cross lamella 2 in a direction away from each other and which are curved, when seen in sectional view, more particularly said boundary surfaces 4 and 5 are parabolic. As is apparent in particular from Figure 2 the boundary surface 4 thereby extends upwards from the lower boundary edge 3 of the lamella along a greater distance than does the boundary surface 5. The upper edges of the lateral boundary surfaces 4 and 5 are interconnected by an upper boundary surface 6, which, assuming that the light box 1 is disposed horizontally as indicated above, includes an angle with the horizontal, seen in sectional view. It will be apparent that the surface of the above-described embodiment which is bounded by the upper boundary surface is thus smaller, measured in the longitudinal direction of the box, than would be the case if the boundary surface 5 were to extend upwards along the same distance as the boundary surface 4, in which case the upper edges of the two boundary surfaces 4 and 5 would be interconnected by a boundary surface extending horizontally, seen in sectional view.
[0016] As already explained above this will make it possible to achieve an enhanced efficiency of the light box and the light source(s) provided therein.
[0017] Because of the asymmetric shape of the lamella also the screening angle for the light emission will become asymmetric, as will be apparent from the angles æ and β indicated in Figure 2. In order to obtain an even distribution of the emitted light all the same, the lamellae 2 in the box 1 are preferably arranged mirror-symmetric with respect to the centre transverse plane of the light box 1, as illustrated for four lamellae in Figure 2.
[0018] As is illustrated in more detail for the embodiment shown in Figure 4, the upper boundary surface 6 may also be curved rather than being made up of a straight surface.
[0019] In order to further influence the angle at which the light is emitted the upper surface 6 may be provided with ribs extending transversely to the longitudinal direction of the lamella, substantially in the longitudinal direction of the box, therefore, and/or with perforations and/or be covered with a foil having a prismatic structure, which has a light-deflecting function.
[0020] The cross lamella 2 shown in Figures 5 - 7 likewise has two lateral boundary surfaces 4 and 5, which extend upwards from a lower boundary edge 3 of the cross lamella 2 in a direction away from each other and which are preferably curved, when seen in sectional view, more particularly said boundary surfaces 4 and 5 are parabolic.
[0021] The upper edges of the lateral boundary surfaces 4 and 5 are interconnected by an upper boundary surface 6, which in the usual user position includes an angle with the horizontal, as is illustrated in Figure 7.
[0022] As furthermore appears in particular from Figure 6 the connecting lines 7 and 8 between the side edges of the upper boundary surface 6 and the upper edges of the lateral boundary surfaces 4 and 5 are curved in this embodiment. As furthermore appears from Figure 6 the centre of curvature of the connecting line 8 is thereby located at the side of the connecting line 8 remote from the connecting line 7. Similarly the centre of curvature of the connecting line 7 is located at the side of the connecting line 7 remote from the connecting line 8.
[0023] As will furthermore be apparent from Figure 6 the width of the upper boundary surface 6 thereby gradually decreases from the ends of the cross lamella towards the centre of the cross lamella, seen in plan view.
[0024] It will be apparent that as a result of lamellae thus shaped being used in a light box the non-transmitting surface formed by the upper boundary surfaces 6 will be comparatively small, so that when lamellae of this type are used in a light box less light from the light source(s) will be screened and thus the efficiency will be enhanced.
1. A light box, in which a plurality of cross lamellae (2) are disposed at least substantially
parallel to each other under (a) light source(s), transversely to the longitudinal
direction of said box, and whereby a cross lamella (2) is bounded by lateral boundary
surfaces (4, 5) sloping upwards from the lower boundary edge (3) of the lamella (2)
in a direction away from each other, said lateral boundary surfaces (4, 5) being interconnected
near their upper edges by an upper boundary surface (6), in such a manner that the
cross lamella (2) is substantially triangular, seen in sectional view, and whereby
the one lateral boundary surface (4) extends upwards from the lower boundary edge
(3) of the cross lamella (2) along a greater distance than does the other lateral
boundary surface (5), and said cross lamellae (2) are arranged mirror-symmetrically
relative to the centre plane of the light box transverse to the longitudinal axis
of the light box, characterized in that the upper boundary surfaces of the cross lamellae
are sloping downward in the direction towards said centre plane.
2. A light box according to claim 1, characterized in that the lower boundary edge (3)
of the cross lamella (2) extends rectilinearly.
3. A light box according to claim 1 or 2, characterized in that the upper boundary edges
of the lateral boundary surfaces (4, 5) extend parallel to the lower boundary edge
(3) of the lamella (2).
4. A light box according to claim 1 or 2, characterized in that the upper boundary edges
of the lateral boundary surfaces (4, 5) are curved.
5. A light box according to any one of the preceding claims, characterized in that the
upper boundary surface (6) is provided with ribs extending in the longitudinal direction
of the cross lamella (2).
6. A light box according to any one of the preceding claims, characterized in that the
upper boundary surface (6) of the cross lamella (2) is provided with perforations.
7. A light box according to any one of the preceding claims, characterized in that the
upper boundary surface (6) is covered with a foil having a prismatic structure, which
has a light-deflecting function.
8. A light box according to any one of the preceding claims, characterized in that the
connecting lines (7, 8) between the side edges of the upper boundary surface (6) and
the upper edges of the lateral boundary surfaces (4, 5) are both curved, whereby the
centre of curvature of each connecting line (7, 8) is located at the side of the respective
connecting line (7, 8) remote from the other connecting line (8, 7).
1. Leuchtenkasten, in welchem eine Vielzahl von Querlamellen (2) im wesentlichen parallel
zueinander und quer zur Längsrichtung des Leuchtenkastens unter (einer) Lichtquelle(n)
angeordnet sind, wobei eine Querlamelle (2) durch seitliche Begrenzungsoberflächen
(4, 5) begrenzt ist, welche Begrenzungsoberflächen (4, 5) nach oben hin von dem unteren
Begrenzungsrand (3) der Lamelle (2) weg und voneinander weg verlaufen, und die seitlichen
Begrenzungsoberflächen (4, 5) in der Nähe ihres oberen Randes durch eine obere Begrenzungsfläche
(6) derart miteinander verbunden sind, daß die Querlamelle (2) im wesentlichen dreieckförmig
im Querschnitt ausgebildet ist und wobei die eine seitliche Begrenzungsoberfläche
(4) nach oben hin von dem unteren Begrenzungsrand (3) der Querlamelle (2) entlang
einer größeren Strecke sich erstreckt als die andere seitliche Begrenzungsoberfläche
(5) und die Querlamellen (2) spiegelsymmetrisch im Bezug auf die Mittelfläche des
Leuchtenkastens und quer zur Längsachse des Leuchtenkastens angeordnet sind, dadurch gekennzeichnet, daß die oberen Begrenzungsoberflächen der Querlamellen (2) nach unten hin in Richtung
dieser Mittelfläche verlaufen.
2. Leuchtenkasten, nach Anspruch 1, dadurch gekennzeichnet, daß die unteren Begrenzungsränder (3) der Querlamelle (2) geradlinig verlaufen.
3. Leuchtenkasten, nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, daß die oberen Begrenzungsränder der seitlichen Begrenzungsoberflächen (4, 5) sich
parallel zum unteren Begrenzungsrand (3) der Lamelle (2) erstrecken.
4. Leuchtenkasten, nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, daß die oberen Begrenzungsränder der seitlichen Begrenzungsoberflächen (4, 5) bogenförmig
ausgebildet sind.
5. Leuchtenkasten, nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die obere Begrenzungsfläche (6) mit Rippen ausgestattet ist, welche sich in Längsrichtung
der Querlamelle (2) erstrecken.
6. Leuchtenkasten, nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die obere Begrenzungsfläche (6) der Querlamelle (2) mit Perforationen ausgestattet
ist.
7. Leuchtenkasten, nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die obere Begrenzungsfläche (6) mit einer Folie bedeckt ist, welche eine prismatische
Struktur mit lichtablenkender Wirkung aufweist.
8. Leuchtenkasten, nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die Verbindungslinien (7, 8) zwischen den seitlichen Rändern der oberen Begrenzungsoberflächen
(6) und den oberen Rändern der seitlichen Begrenzungsoberflächen (4, 5) beide bogenförmig
ausgebildet sind, wobei das Zentrum des Bogens jeder Verbindungslinie (7, 8) auf der
Seite der jeweiligen Verbindungslinie (7, 8) liegt, welche von der anderen Verbindungslinie
(8, 7) weiter entfernt liegt.
1. Caisson lumineux, dans lequel une pluralité de lamelles transversales (2) sont disposées
au moins sensiblement parallèlement les unes aux autres sous une ou plusieurs sources
de lumière, transversalement à la direction longitudinale dudit caisson, et de sorte
qu'une lamelle transversale (2) est définie par des surfaces latérales de délimitation
(4,5) qui s'inclinent vers le haut à partir du bord inférieur de délimitation (3)
de la lamelle (2) dans des directions s'écartant l'une de l'autre, lesdites surfaces
latérales de délimitation (4, 5) étant interconnectées près de leurs bords supérieurs
par une surface supérieure de délimitation (6) d'une manière telle que la lamelle
transversale (2) est sensiblement triangulaire, vue en coupe, et de sorte que la dite
une surface latérale de délimitation (4) s'étend vers le haut à partir du bord inférieur
de délimitation (3) de la lamelle transversale (2) le long d'une plus grande distance
que ne le fait l'autre surface latérale de délimitation (5), et lesdites lamelles
transversales (2) sont agencées symétriquement par rapport au plan central du caisson
lumineux qui est transversal à l'axe longitudinal du caisson lumineux, caractérisé
en ce que les surfaces supérieures de délimitation des lamelles transversales s'inclinent
vers le bas dans la direction vers ledit plan central.
2. Caisson lumineux selon la revendication 1, caractérisé en ce que le bord inférieur
de délimitation (3) de la lamelle transversale (2) s'étend de façon rectiligne.
3. Caisson lumineux selon la revendication 1 ou 2, caractérisé en ce que les bords supérieurs
de délimitation des surfaces latérales de délimitation (4,5) s'étendent parallèlement
au bord inférieur de délimitation (3) de la lamelle (2).
4. Caisson lumineux selon la revendication 1 ou 2, caractérisé en ce que les bords supérieurs
de délimitation des surfaces latérales de délimitation (4, 5) sont courbes.
5. Caisson lumineux selon une quelconque des revendications précédentes, caractérisé
en ce que la surface supérieure de délimitation (6) est pourvue de nervures s'étendant
dans la direction longitudinale de la lamelle transversale (2).
6. Caisson lumineux selon une quelconque des revendications précédentes, caractérisé
en ce que la surface supérieure de délimitation (6) de la lamelle transversale (2)
comporte des perforations.
7. Caisson lumineux selon une quelconque des revendications précédentes, caractérisé
en ce que la surface supérieure de délimitation (6) est recouverte d'une pellicule
ayant une structure prismatique, qui a une fonction de déviation de la lumière.
8. Caisson lumineux selon une quelconque des revendications précédentes, caractérisé
en ce que les lignes de jonction (7,8) entre les bords latéraux de la surface supérieure
de délimitation (6) et les bords supérieurs des surfaces latérales de délimitation
(4,5) sont toutes deux courbes, de sorte que le centre de courbure de chaque ligne
de jonction (7,8) est situé sur le côté de la ligne de jonction respective (7,8) qui
est à l'opposé de l'autre ligne de jonction (8,7).