WO2022152595A1

WO2022152595A1 - A light emitting device

Info

Publication number: WO2022152595A1
Application number: PCT/EP2022/050085
Authority: WO
Inventors: Peter Johannes Martinus BUKKEMS; Martinus Hermanus Wilhelmus Maria Van Delden; Bartel Marinus Van De Sluis
Original assignee: Signify Holding B.V.
Priority date: 2021-01-12
Filing date: 2022-01-04
Publication date: 2022-07-21

Abstract

A light emitting device (1) comprising a LED foil (10), the LED foil (10) comprising a backbone structure (11) extending along a central axis (CA), and a plurality of slits (141, 142) extending from edges (131, 132) of the LED foil (10) towards the backbone structure (11). The plurality of slits (141, 142) forms a plurality of foil sections (151, 152) extending from edges (131, 132) of the LED foil (10) towards the backbone structure (11). The plurality of foil sections (151, 152) each comprise a free end (161, 162) opposite to the backbone structure (11) and are twistable around the central axis (CA).

Description

A light emitting device

FIELD OF THE INVENTION

The invention relates to a light emitting device comprising a LED foil comprising a backbone structure extending along a central axis, and to a luminaire comprising such a light emitting device.

BACKGROUND OF THE INVENTION

With the development of 3D printing the possibility of cheaply and efficiently creating complex shapes has emerged. 3D printing may for example be used for manufacturing housings for lamps with complex shapes. However, complex housing geometries also put constraints and requirements on lighting elements to be arranged within the housing.

Complex lighting elements are known in the art. For instance, TW M263240 U discloses an LED structure manufactured in 2D, and thus initially being flat, and having semicircular slits arranged such as to enable the structure to be expanded into a 3D-structure which is spherical composed of semicircular elements arranged concentrically with respect to one another, somewhat similar to a traditional rice paper lamp. The LED structure has a central, linear joining portion. The semicircular linear elements are twistable around the central, linear joining portion, but mutually opposite linear elements are twistable only in dependence of one another.

To be able to arrange the lighting elements within complex shaped housings it is required to provide a flexible lighting element, which fulfill the requirements and constraints imposed by complex shaped housings.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved light emitting device with an improved flexibility and which fulfill the requirements and constraints imposed by complex shaped housings.

These and other objects of the invention are achieved by a light emitting device comprising a LED foil comprising a backbone structure extending along a central axis, and a plurality of slits extending from edges of the LED foil towards the backbone structure, where the plurality of slits forms a plurality of foil sections extending from edges of the LED foil towards the backbone structure, where the plurality of foil sections comprises a plurality of LED nodes, where the plurality of foil sections each comprise a free end opposite to the backbone structure, and where the plurality of foil sections is twistable around the central axis.

Consequently, and especially by providing that the plurality of foil sections each comprise a free end opposite to the backbone structure, and that the plurality of foil sections is twistable around the central axis, a flexible light emitting device is achieved which may be twisted to create a desired light source, e.g. the light emitting device may be twisted to create an omnidirectional light emitting device or be left untwisted in a planar configuration to achieve a directional light emitting device. Furthermore, the light emitting device may be twisted into a desired shape giving freedom when choosing a housing for the light emitting device and when arranging the light emitting device in a living space. By providing slits stress in the LED foil caused by flexing is reduced, thus allowing for the foil section to be twisted around the central axis.

In the context of this invention the central axis should not be construed as an axis necessarily intersecting a center of LED foil, however, the central axis may intersect a center of the LED foil. The central axis may be any axis on the LED foil. For instance, the central axis may also be offset with respect to a center of the LED foil such as to obtain an asymmetrical configuration as an alternative to a symmetric configuration.

In an embodiment the plurality of LED nodes comprises a plurality of RGB nodes.

Consequently, the light emitting device is capable of emitting a large variety of colors. Furthermore, the plurality of LED nodes may comprise a plurality of white light nodes capable of emitting white light of a certain color temperature.

In an embodiment the backbone structure comprises one or more conductors, where the plurality of LED nodes is electrically connected to the one or more conductors.

Consequently, a space efficient light emitting device is achieved which does not require external conductors. Preferably, the one or more conductors are connectable to a power source capable of powering the plurality of LED nodes. Twisting of the one or more conductors is also limited by the backbone structure comprising the one or more conductors, thus potentially obviating connection issues arising from twisting of the one or more conductors. The backbone structure may comprise a bus bar for controlling power delivered to the plurality of LED nodes.

In an embodiment the one or more conductors are electrically connectable to a controller configured to control operation of the plurality of LED nodes.

Consequently, operation of the plurality of LED nodes may be controlled via the controller. The one or more conductors may then act as both power lines and data lines. The controller may control a color emitted by the plurality of LED nodes, a brightness of the plurality of LED nodes, and/or on/off switching of the plurality of LED nodes. The controller may transmit control signals to a single LED node within the plurality of LED nodes. The controller may transmit control signals to a group of LED nodes within the plurality of LED nodes.

In an embodiment a reinforcement element is connected to the backbone structure, and the reinforcement element extends in parallel with the backbone structure along the central axis.

Consequently, mechanical stability is provided to the light emitting device. The reinforcement may be also hinder the plurality of slits from propagating through the backbone structure. The reinforcement element may be advantageous in a manufacturing setting when the slits are formed in the LED foil, then the reinforcement element may assure the slits are not formed through the backbone structure.

The reinforcement element may be provided as oblong element connected to the backbone structure, e.g. a bar adhered or mechanically connected to the backbone structure. In embodiments where the backbone structure comprises electrical components, the reinforcement element may act as an electrical insulator insulating the electrical components from a surrounding environment, e.g. by being placed on top of the electrical components.

In an embodiment the plurality of slits comprises one or more first slits and one or more second slits, where the one or more first slits extends from a first edge of the LED foil towards the backbone structure and the one or more second slits extends from a second edge of the LED foil towards the backbone structure, where the first edge is opposite the second edge, where the one or more first slits form one or more first foil sections, and where the one or more second slits form one or more second foil sections.

Consequently, the foil sections are separated by the backbone structure into two groups. The one or more first foil sections may be twisted separately from the one or more second foil sections, consequently, giving a higher degree of freedom in the shaping of the light emitting device. In an embodiment ends of the foil sections at the edges of the LED foil are interconnected.

Consequently, mechanical stability is provided to the light emitting device. Furthermore, by interconnecting the ends of the foil sections a higher degree of control over the relative positioning between the foil sections is achieved. The ends may be interconnected by a wire threaded/penetrating through the ends of the foil sections.

In an embodiment the ends of the first foil sections at the edges of the LED foil are interconnected, and ends of the second foil sections at the edges of the LED foil are interconnected.

Consequently, a high degree of control is obtained over the relative positioning of the first foil sections and the second foil section independently from each other.

In an embodiment the plurality of slits extends perpendicularly to the central axis.

Consequently, twisting of the foil sections around the central axis is facilitated. Having the slits extending perpendicularly to the central axis facilitates twisting of the foil sections in a plane perpendicular to the central axis.

In an embodiment the backbone structure is folded along the central axis.

Consequently, by folding the backbone structure the surface area of the backbone structure may be increased in an efficient manner. An increased surface area creates more room for additional components such as connectors and/or reinforcement elements.

Preferably, the backbone structure is folded to have a V-shaped or W-shaped cross-section in a plane perpendicular to the central axis. Furthermore, folding the backbone structure may increase the twistability of the foil sections by creating a hinge like connection between the backbone structure and the foil sections.

The backbone structure may be folded so the LED foil is symmetric about the central axis, e.g. the folding line splitting the LED foil into two equal portions. Alternatively, the backbone structure may be folded so the LED foil is not symmetric about the central axis, e.g. the folding line splitting the LED foil into two unequal portions.

In an embodiment the plurality of slits is provided during manufacture of the light emitting device. In an alternative embodiment, the LED foil comprises cutting lines or linear perforations indicating where to provide the plurality of slits subsequent to manufacture of the light emitting device. Providing the slits during manufacture may assure the slits are correctly formed with a high degree of precision. Having the LED comprising cutting lines or linear perforations provides a high degree of freedom, as the light emitting device may be adapted on-site dependent on the circumstances.

In an embodiment the light emitting device further comprises an extension or a strap.

The extension or strap may serve a wide variety of purposes. The extension or strap may ease handling of the light emitting device by providing a structure with which a user can interact. The extension or strap may be used for mounting of the light emitting device to a mounting structure, e.g. a hook. The extension or strap may facilitate introducing the light emitting device into a housing, as the light emitting device may be pulled into the housing via the extension or the strap.

The objects of the invention are furthermore achieved by a luminaire comprising a light emitting device according to the invention.

In an embodiment the luminaire further comprises a housing or a light diffusing housing, where the light emitting device is arranged in the housing.

Consequently, the light emitting device is protected by the housing from impacts, dirt and other contaminants.

In an embodiment the housing is configured to receive the light emitting device in a non-twisted condition, and the light emitting device is twisted by being introduced into the housing.

Consequently, the light emitting device may be introduced into a housing with a complex geometry in a simple manner, where the light emitting device twists to adapt to the housing geometry. Furthermore, when the twisting of the light emitting structure is a known entity and when the placement of LED nodes within the housing is also a known entity, consequently, the placement of LED nodes within housing of a complex geometry is controllable.

In an embodiment the light emitting device further comprises an extension or a strap, and the light emitting device is introduced into the housing by pulling the extension or strap.

It is noted that the invention relates to all possible combinations of features recited in the claims. Other objectives, features, and advantages of the present inventive concept will appear from the following detailed disclosure, from the attached claims as well as from the drawings. A feature described in relation to one of the aspects may also be incorporated in the other aspect, and the advantage of the feature is applicable to all aspects in which it is incorporated.

BRIEF DESCRIPTION OF THE DRAWINGS

This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiments of the invention.

As illustrated in the figures, the sizes of layers and regions are exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of embodiments of the present invention. Like reference numerals refer to like elements throughout.

Fig. 1 shows a schematic front view of a light emitting device according to an embodiment of the invention.

Fig. 2 shows a schematic perspective view of a light emitting device according to an embodiment of the invention.

Fig. 3 A and Fig. 3B show schematic cross-sectional views of different light emitting devices in a plane perpendicular to a central axis CA of the light emitting devices according to different embodiments of the invention.

Fig. 4 shows a perspective schematic view of a luminaire according to an embodiment of the invention.

DETAILED DESCRIPTION

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

Referring initially to Fig. 1, showing a schematic front view of a light emitting device 1 according to an embodiment of the invention. The light emitting device 1 comprises a LED foil 10. The LED foil 10 may be provided as a printed circuit board (PCB). The LED foil is provided as a substantially planar sheet with a first main surface and an opposing second main surface. On Fig. 1 the first main surface is the surface of the LED foil 10 facing out of the paper, while the second main surface faces onto the paper and is therefore not visible on Fig. 1. The LED foil 10 comprises a backbone structure 11. The backbone structure 11 extends longitudinally along a central axis CA. The backbone structure 11 comprises one or more conductors 111. The one or more conductors 111 may be provided as lines of conductive material in the backbone structure. The one or more conductors 111 are connected to a plurality of LED nodes 12. The one or more conductors 111 are further connected to a controller 2. The controller 2 is configured for providing an electric signal to the plurality of LED nodes 12. The electric signal provided by the controller 2 may be for powering the plurality of LED nodes 12 and/or for controlling operation of the plurality of LED nodes 12. The one or more conductors 111 may thus act as both power lines and data lines connecting the plurality of LED nodes 12 to the controller 2. The backbone structure 11 further comprises a reinforcement element 112. The reinforcement element 112 extends longitudinally in parallel with the backbone structure 11. The reinforcement element 112 is connected to the backbone structure 11. The connection between the backbone structure 11 and the reinforcement element 112 may be carried out by adhering the reinforcement element 112 to the backbone structure 11, alternatively the reinforcement element 112 may be soldered or mechanically fastened to the backbone structure 11. The reinforcement element 112 may be provided in the form of a bar or any other oblong element being of a more rigid or stiff structure than the LED foil 10.

Extending from edges 131, 132 of the led foil 10 is a plurality of slits 141, 142. The plurality of slits 141, 142 extends from the edges 131, 132 and towards the backbone structure 11. The plurality of slits 141, 142 form a plurality of foil sections 151, 152 or subdivide the LED foil 10 into a plurality of foil sections 151, 152. In the shown embodiment the plurality of slits comprises a first plurality of slits 141 and a second plurality of slits 142. The first plurality of slits 141 extends from a first edge 131 of the LED foil 10 towards the backbone structure 11. The second plurality of slits 142 extends from a second edge 132 of the LED foil 10 towards the backbone structure 11. The first edge 131 is opposite to the second edge 132 on the LED foil 10. The plurality of first slits 141 form a plurality of first foil sections 151. In other words, the plurality of first slits 141 subdivide a first part of the LED foil 10 into a plurality of first foil sections 151. The plurality of second slits 142 form a plurality of second foil sections 151. In other words, the plurality of second slits 142 subdivide a second part of the LED foil 10 into a plurality of second foil sections 152. In the shown embodiment the plurality of slits extends from the edges 131, 132 perpendicularly to the central axis CA. In the shown embodiment the first plurality of slits 141 extends symmetrically with the second plurality of slits 142 with the central axis CA defining the symmetry axis. The plurality of foil sections 151, 152 comprise a plurality of LED nodes 12. The plurality of foil sections 151, 152 extends from the backbone structure 11. The plurality of foil sections 151, 152 extends perpendicularly to the central axis CA. The plurality of foil sections 151, 152 each comprise a free end 161, 162 opposite to the backbone structure 11. Each first foil section 151 of the plurality of first foil sections 151 thus comprises a free end 161 at the first edge 131. Likewise, each second foil section 152 of the plurality of second foil sections 152 thus comprises a free end 162 at the second edge 132. The plurality of foil sections 151, 152 is twistable around the central axis CA.

The light emitting device 1 further comprises an extension 17 for handling the light emitting device.

The plurality of LED nodes 12 are configured to mainly emit light in directions perpendicular to the first main surface and the second main surface. The plurality of LED nodes 12 may be RGB nodes capable of emitting light with different wavelengths. The plurality of LED nodes 12 are distributed on the plurality of foil sections 151, 152. In some embodiments the plurality of LED nodes 12 are evenly distributed over the foil section 151, 152. In some embodiments each foil section comprises at least one, two, three, four, five or more LED nodes. The LED nodes comprised by a foil section may be evenly distributed over the foil section.

In the embodiment shown on Fig. 1 the plurality of foil sections 151, 152 are not twisted around the central axis CA. Consequently, the first main surface faces toward a first direction being substantially out of the paper on Fig. 1 and the second main surfaces faces towards a second direction opposite the first direction and thus substantially into the paper on Fig. 1. Therefore, the plurality of LED nodes, in operation, mainly emits light in the first direction and the second direction, thus rendering the light emitting device 1 as directional light emitting device.

Referring to Fig. 2, a schematic perspective view of a light emitting device 1 according to an embodiment of the invention is shown. A longitudinal end 113 of the backbone structure 11 of the light emitting device 1 is fixated to a mounting structure 3. The fixation may be carried out by adhering or clamping the light emitting device to the mounting structure 3. In the shown embodiment the edges of the free ends of the plurality of foil sections 151, 152 are filleted to create rounded comers. Having rounded corners may ease handling of the light emitting device 1 and reduce the risk of a user handling the light emitting device 1 cutting themselves. Alternatively, the free ends of the plurality of foil sections 151, 152 could be chamfered. The plurality of foil sections 151, 152 is twisted to form a helical shape around the central axis CA. The helical shape assures the plurality of LED nodes 12 comprised by the plurality of foil sections 151, 152 are capable of emitting light in a plurality of directions, thus achieving an omnidirectional light emitting device 1.

Referring to Fig. 3a and Fig. 3b, schematic cross-sectional views of different light emitting devices 1 in a plane perpendicular to a central axis CA of the light emitting devices 1 according to different embodiments of the invention are shown.

In Fig. 3a the backbone structure 11 has been folded along the central axis CA to form a cross-section in the general form of a W. In Fig. 3b the backbone structure 11 has been folded along the central axis CA to form a cross-section in the general form of a V. Folding the backbone structure 11 increases the surface area of backbone structure 11, thus providing additional space for connecting elements to the backbone structure 11, or for providing circuitry on or within the backbone structure 11, e.g. additional space for data lines and/or power lines. Folding of the backbone structure 11 may also increase the flexibility of the plurality of foil sections 151, 152 by providing a hinge-like mechanism between the backbone structure 11 and the plurality of foil sections 151, 152.

Referring to Fig. 4, a perspective schematic view of a luminaire 100 according to an embodiment of the invention is shown.

In the shown embodiment the light emitting device 1 is arranged in a housing 4. The housing 4 is formed from a transparent material. The housing 4 is shaped with helical shape. The housing may be manufactured via a 3D-printing process. The housing 4 may be a light diffusing housing. The light emitting device 1 is arranged in the housing 4 by introducing it through an open end of the housing 4. The open end of the housing 4 may be configured to receive the light emitting device 1 in a non-twisted condition. The light emitting device 1 may be introduced into the housing 4, and by being introduced into the housing 4 the light emitting device 1 is twisted. For example, in the shown embodiment with a helical housing 4 the light emitting device 1 may twist to conform to the helical shape of the housing 4, while being introduced into the housing 4. The light emitting device 1 may be introduced into the housing 4 by pulling or pushing the light emitting device 1 into the housing 4. In some embodiments the light emitting device may comprise an extension or a strap allowing the light emitting device 1 to be pulled into a housing 4.

The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person 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 measured cannot be used to advantage.

Claims

CLAIMS:

1. A light emitting device (1) comprising: a LED foil (10) comprising a backbone structure (11) extending along a central axis, and a plurality of slits (141, 142) extending from edges (131, 132) of the LED foil (10) towards the backbone structure (11), wherein the plurality of slits (141, 142) forms a plurality of foil sections (151, 152) extending from edges of the LED foil (10) towards the backbone structure (11), wherein the plurality of foil sections (151, 152) comprises a plurality of LED nodes (12), wherein the plurality of foil sections (151, 152) each comprise a free end (161, 162) opposite to the backbone structure (11), and wherein the plurality of foil sections (151, 152) is twisted to form a helical shape around the central axis.

2. A light emitting device (1) according to claim 1, wherein the backbone structure (11) comprises one or more conductors (111), wherein the plurality of LED nodes (12) is electrically connected to the one or more conductors (111).

3. A light emitting device (1) according to claim 2, wherein the one or more conductors (111) are electrically connectable to a controller (2) configured to control operation of the plurality of LED nodes (12).

4. A light emitting device (1) according to any one of the preceding claims, wherein a reinforcement element (112) is connected to the backbone structure (111), and wherein the reinforcement element (112) extends in parallel with the backbone structure (111) along the central axis.

5. A light emitting device (1) according to any one of the preceding claims, wherein the plurality of slits (141, 142) comprises one or more first slits (141) and one or more second slits (142), wherein the one or more first slits (141) extends from a first edge (131) of the LED foil (10) towards the backbone structure (11) and the one or more second slits (142) extends from a second edge (132) of the LED foil (10) towards the backbone structure (11), wherein the first edge (131) is opposite the second edge (132), wherein the one or more first slits (141) form one or more first foil sections (151), wherein the one or more second slits (142) form one or more second foil sections (152).

6. A light emitting device (1) according to any one of the preceding claims, wherein ends of the foil sections (151, 152) at the edges (131, 132) of the LED foil (10) are interconnected.

7. A light emitting device (1) according to claim 5 and 6, wherein ends of the first foil sections (151) at the edges of the LED foil (10) are interconnected, and wherein ends of the second foil sections (152) at the edges of the LED (10) foil are interconnected.

8. A light emitting device (1) according to any one of the preceding claims, wherein the plurality of slits (141, 142) extends perpendicularly to the central axis.

9. A light emitting device (1) according to any one of the preceding claims, wherein the backbone structure (11) is folded along the central axis.

10. A light emitting device (1) according to any one of the preceding claims, wherein the light emitting device (1) further comprises an extension (17) or a strap.

11. A luminaire comprising a light emitting device (1) according to any one of the preceding claims.

12. A luminaire according to claim 11, the luminaire further comprising a housing or a light diffusing housing, wherein the light emitting device (1) is arranged in the housing.

13. A luminaire according to claim 12, wherein the housing is configured to receive the light emitting device (1) in a non-twisted condition, and wherein the light emitting device (1) is twisted by being introduced into the housing.

14. A luminaire according to claim 12 or 13, the light emitting device (1) further comprises an extension or a strap, and wherein the light emitting device (1) is introduced into the housing by pulling the extension or strap.