Lighting device

Abstract

A lighting device comprising a support panel located between two outer sheets, which support panel is provided with at least one light emitting module, while at least one of the outer sheets is translucent. The outer sheets are movable with respect to each other at least from a folded state in which the support panel and the outer sheets extend substantially parallel to each other and an unfolded state in which the outer sheets are at least partly further spaced apart than in the folded state.

Claims

1. A lighting device comprising; a support panel located between two outer sheets, each of the outer sheets having two parallel longitudinal sides, the outer sheets being movable with respect to each other between a folded state and an unfolded state; wherein, in the folded state, the outer sheets are flat and extend substantially parallel to the support panel, wherein, in the unfolded state, the outer sheets are curved and at least partly further spaced apart than in the folded state, wherein the two parallel longitudinal sides of a first one of the two outer sheets are connected to the respective two parallel longitudinal sides of a second one of the two outer sheets to form first and second sets of interconnected longitudinal sides, wherein the first and second sets of interconnected longitudinal sides are movable towards each other to push the outer sheets spatially apart from each other in the unfolded state, and wherein the support panel comprises at least a light emitting diode as a light emitting module and is located between the outer sheets in the folded state and the unfolded state, said light emitting diode facing at least one of the outer sheets.

2. The lighting device according to claim 1, wherein at least in the unfolded state, the two sets of interconnected longitudinal sides of the outer sheets comprise a mount for the support panel.

3. The lighting device according to claim 1, wherein at least one of the outer sheets comprises a flap being foldable around a fold line that extends between the two parallel longitudinal sides.

4. The lighting device according to claim 3, wherein the fold line is arc-shaped, the convex side of the arc-shaped folding line is located outside the flap.

5. The lighting device according to claim 4, wherein the flap is delimited by the arc-shaped folding line on one side of the flap and an arc-shaped edge on the opposite side of the flap.

6. The lighting device according to claim 5, wherein in the unfolded state the outer sheets are kept spaced apart by the folded flap.

7. The lighting device according to claim 6, wherein one of the outer sheets is reflective, whilst in the unfolded state light emitted by the light emitting module towards the reflective outer sheet is reflected by the reflective outer sheet towards the other translucent outer sheet through the support panel.

8. The lighting device according to claim 7, wherein the support panel is at least partly translucent.

9. The lighting device according to claim 7, wherein the translucent outer sheet is a light diffuser.

10. The lighting device according to claim 9, wherein the reflective outer sheet is opaque.

11. The lighting device according to claim 10, wherein the interconnected longitudinal sides of the outer sheets are connected to each other by fastening means.

12. The lighting device according to claim 11, wherein the light emitting diodes are mounted on both sides of the support panel, each facing a respective one of the outer sheets.

13. The lighting device according to claim 1, wherein both the outer sheets are translucent.

14. The lighting device of claim 1, wherein the support panel comprises a plurality of light emitting diodes.

15. The lighting device of claim 14, wherein a distance between neighboring light emitting diodes on the support panel proximate the longitudinal sides is less than a distance between neighboring light emitting diodes on the support panel near a center portion of the support panel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other aspects of the invention will now be described in more detail, with reference to the appended drawings showing currently preferred embodiments of the inventions, wherein:

(2) FIGS. 1A and 1B show a perspective view and a cross section, respectively of a first embodiment of the lighting device according to the invention in the unfolded state;

(3) FIGS. 2A and 2B show a perspective view and a cross section, respectively of the embodiment as shown in the FIGS. 1A and 1B in the folded state;

(4) FIGS. 3A and 3B show a perspective view and a cross section, respectively of a stack of layers of the lighting device as shown in FIGS. 2A and 2B in the folded state;

(5) FIG. 4A shows a perspective view of a second embodiment of the lighting device according to the invention in the unfolded state; and

(6) FIG. 4B shows a plano of the outer sheets and the flaps of the lighting device as shown in FIG. 4A in a folded state.

DESCRIPTION OF PREFERRED EMBODIMENTS

(7) FIGS. 1A-3B show perspective and cross sectional views of a first embodiment of the lighting device 1 according to the invention. The lighting device 1 comprises a support panel 2 on which light emitting modules 3, for example LEDs, are mounted on one side of the support panel 2. The support panel 2 has two opposite longitudinal sides 4, 5 and two opposite transverse sides 6, 7. The longitudinal sides 4, 5 extend in the direction of the arrow P1.

(8) On the side of the support panel 2 on which the light emitting modules 3 are mounted, the lighting device 1 comprises a reflective outer sheet 8. The reflective outer sheet 8 is provided with a reflective layer 9. The reflective layer 9 is directed towards the light emitting modules 3. The reflective outer sheet 8 has a first and a second parallel longitudinal side 11, 12 which extends in the direction of the arrow P1. Preferably the reflective outer sheet 8 is opaque thus preventing light from being emitted from this side of the lighting device 1.

(9) On the other side of the support panel 2 the lighting device 1 comprises a translucent outer sheet 10. The translucent outer sheet 10 has a first and a second parallel longitudinal side 13, 14 which extends in the direction of the arrow P1.

(10) The first longitudinal side 11 of the reflective outer sheet 8 is connected to the first longitudinal side 13 of the translucent outer sheet 10 by means of a fastening means in the form of an adhesive tape 15. On the opposite side of both curved outer sheets, the second longitudinal side 12 of the reflective outer sheet 8 is connected to the second longitudinal side 14 of the translucent outer sheet 10 by means of a fastening means in the form of an adhesive tape 16.

(11) In the unfolded state as shown in FIGS. 1A and 1B, the outer sheets 8, 10 are spaced apart from each other and spaced apart from the support panel 2 between the interconnected first longitudinal sides 11, 13 and the interconnected second longitudinal sides 12, 14, thus forming a hollow, tube-like member that forms a housing of the lighting device 1.

(12) In the unfolded state, the reflective outer sheet 8 and the translucent outer sheet 10 are curved in such a way that the interconnected first longitudinal sides 11, 13 and the interconnected second longitudinal sides 12, 14 are in contact with the longitudinal sides 4, 5 respectively of the support panel 2.

(13) FIG. 1B shows the lighting device 1 in the unfolded state when in use. Light rays 17 are emitted by the light emitting module 3 towards the reflective outer sheet 8. These light rays 17 are reflected by the reflective outer sheet 8 as light rays 18 which pass through the at least partly translucent support panel 2 in the direction of the translucent outer sheet 10. The translucent outer sheet 10 acts as a diffuser. The light rays 18 that arrive at the translucent outer sheet 10 pass through the translucent outer sheet 10 as a multitude of light rays 19 propagates in a multitude of directions.

(14) The diffusion of the light rays 18 reduces the intensity of the light. The light rays 19 that pass through the translucent outer sheet have an intensity that is far less than the intensity of the light rays 18. Glare, which is caused as a result of high intensity light rays, is therefore reduced to a large extent.

(15) In the folded state, the support panel 2, the reflective outer sheet 8 and the translucent outer sheet 10 are all flat, as shown in FIGS. 2A-3B. The distance X1 between the longitudinal sides 4, 5 of the support panel 2 is smaller than the distance X2 between the longitudinal sides 11, 12 of the first outer sheet 8 and smaller than the same distance X2 between the longitudinal sides 13, 14 of the second outer sheet 10.

(16) In the folded state the reflective outer sheet 8 is adjacent to the light emitting modules, thus forming a protective layer for the light emitting modules 3, for example during storage and transport.

(17) When assembling the lighting device 1 from the folded into the unfolded state, a user can push the interconnected first longitudinal sides 11, 12 and second longitudinal sides 13, 14 towards each other, thus reducing the distance between the interconnected longitudinal sides 11, 12 and 13, 14 with respect to each other. The distance between the interconnected first and second longitudinal sides 11, 12 and 13, 14 is reduced from distance X2 to distance X1. As the support panel 2 also has a distance X1 between the longitudinal sides 4, 5, the reduction of the distance X2 to X1 allows the support panel 2 to be held at the longitudinal sides 11, 12 and 13, 14 of the outer sheets.

(18) When reducing the distance X2 to the distance X1, the reflective outer sheets 8 and the translucent outer sheet 10 are being curved in such a way that both outer sheets become spaced apart from each other and also become spaced apart from the support panel 2. To allow the curvature of reflective outer sheet 8 and translucent outer sheet 10, both outer sheets 8, 10 are made from a flexible material.

(19) In the region of the adhesive tape 15, 16, the reflective outer sheet 8 and the translucent outer sheet 10 are adjacent to each other and tilted with respect to each other. The angle that is defined between the reflective outer sheet 8 and the translucent outer sheet 10 forms the space in which the support panel 2 is held. The support panel 2 can be tightly fitted between the longitudinal sides 11, 12 and 13, 14, thus being firmly mounted without any play in the transverse direction. The lighting device 1 can be maintained in the unfolded state by several means, for example by attaching the longitudinal sides 4, 5 of the support panel 2 to the interconnected longitudinal sides 11, 12 respectively.

(20) The distance between adjacent light emitting modules 3 on the support panel 2 near the longitudinal sides 11, 12, 13, 14 is preferably smaller than the distance between adjacent light emitting modules 3 located near the center of the support panel 2, so that over the whole lighting device the total length of a light path from the light emitting modules 3 on the support panel 2 towards the reflective outer sheet 8 and then back through the support panel 2 towards the translucent outer sheet 10 is slightly larger than the distance between adjacent light emitting modules 3 on the support panel 2.

(21) FIGS. 4A-4B show a lighting device 30 according to the invention in the unfolded state (FIG. 4A) and in the folded state (FIG. 4B).

(22) The lighting device 30 comprises a support panel with light emitting modules (not shown), a reflective outer sheet 31 and a translucent sheet 32. In the folded state, as shown in FIG. 4B, the reflective outer sheet 31 and the translucent sheet 32 are connected to each other at longitudinal sides 33, 34 which form a fold line 35. Longitudinal sides 36, 37 of the outer sheet 31, 32 are located on both sides of the fold line 35. In the folded state both outer sheets 33, 34 are located in the same place.

(23) On the transverse sides of the reflective outer sheet 31 and the translucent outer sheet 32 flaps are formed. The flaps 38, 39 are connected to the respective outer sheets 31, 32 via arc-shaped fold lines 40, 41. The arc-shaped fold lines 40 extend between the longitudinal sides 33, 36 of the reflective outer sheet 31. The fold lines 41 extend between the longitudinal sides 34, 37 of the translucent outer sheet 32. The arc-shaped fold lined 40, 41 are such that the convex side of the arc-shaped fold lines 40, 41 is located outside the flap 38, 39 and on the outer sheets 31, 32. The outer edge side 42 of the flaps 38, 39 that delimits the flaps 38, 39 on the side opposite to the arc-shaped fold lines 40, 41 has preferably the same arc-shaped form as the arc-shaped fold lines 40, 41. The concave side of the arc-shaped edge side 42 is directed towards the flap 38, 39.

(24) When assembling the lighting device 30 from the folded to the unfolded state, the reflective outer sheet 31 and the translucent outer sheet 32 are folded about the fold line 35 in such a way that the longitudinal side 36 of the reflective outer sheet 31 and the longitudinal side 37 of the translucent outer sheet 32 become adjacent to each other. Both longitudinal sides 36, 37 are connected to each other by means of fastening means like tape. The interconnected longitudinal sides 33, 34 and the interconnected longitudinal sides 36, 37 are then moved towards each other, thus causing the outer sheets 31, 32 to curve into an arc-shaped form and to become at least partly spaced apart from each other. The outer sheets 31, 32 form a hollow, tube-like member. Subsequently, the flaps 38, 39 are folded about the arc-shaped fold lines 40, 41 through an angle of approximately 90 degrees, in order to cover an opening on the transverse side of the tube-like member.

(25) First, the flap 38 is folded about the fold line 40 until its edge side 42 is adjacent to the fold line 41 of the flap 39. Then the flap 39 is folded about the fold line 41 until its edge side 42 is adjacent to the fold line 40 of the flap 38. The folded flaps 38, 39 allow the lighting device 30 to be kept in the unfolded state as to preserve its constructive integrity. The flaps 38, 39 prevent the outer sheets 31, 32 to return to the folded, flat state and ensure that the reflective outer sheet 31 and the translucent outer sheet 32 remain spaced apart.

(26) Alternatively also other means can be used to keep the reflective outer sheet 31 and the translucent outer sheet 32 spaced apart in the unfolded state. To this end, spacers, rods or flaps of any other form can be used that are mounted in the transverse opening between the reflective outer sheet 31 and the translucent outer sheet 32.

(27) The support panel 2 can be a wire grid or a stretched lead frame onto which light emitting modules are mounted.

(28) The fastening means to interconnect the reflective outer sheet and the translucent outer sheet are not limited to adhesive tape. Other possible fastening means can be, for example, a glue, rings, buttons or a sewn thread.

(29) Alternatively the support panel 2 can be held between the outer sheets by other mounting means. To this end the longitudinal sides of the support panel 2 can be provided with protrusions, such as pins, that protrude at least from one of the outer sheets while holding the support panel in place. The other mounting means can also comprise folded cut-outs in the outer sheets that allow mounting of the support panel.

(30) It is also possible that both outer sheets are translucent.

(31) It is further noted that a lighting device can be provided wherein light emitting modules are mounted on both sides of the support panel each facing one of the translucent outer sheets.

(32) Such a light emitting module on the side of the support panel facing the translucent outer sheet allows light of relatively high intensity to be distributed through the translucent outer sheet and towards the exterior.

(33) The person skilled in the art will realize that the present invention is by no means limited to the preferred embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the scope should not be construed as limiting the scope of the claims.

LIST OF REFERENCE SIGNS

(34) 1 lighting device 2 support panel 3 light emitting module 4 side 5 side 6 side 7 side 8 outer sheet 9 layer 10 outer sheet 11 side 12 side 13 side 14 side 15 tape 16 tape 17 light rays 18 light rays 19 light rays 30 lighting device 31 outer sheet 32 outer sheet 33 side 34 side 35 fold line 36 side 37 side 38 flap 39 flap 40 fold line 41 fold line 42 edge side P1 arrow X1 distance X2 distance X3 distance