FLEXIBLE LIGHT STRIP

Abstract

The invention describes a flexible light strip, an automotive light unit comprising this flexible light strip, an embossing tool and a method to manufacture the light strip, which comprises multiple solid state lighting units as light sources and a flexible carrier for the solid state lighting units attached to the flexible foil, which further comprises a suitable wiring or the carrier is the wiring connecting the solid state lighting units to enable suitable driving of the lighting units to illuminate an environment with the flexible light strip, wherein the carrier comprises multiple buffer areas arranged between adjacent lighting units, where the buffer area extends along a width of the carrier from one edge to the opposite edge of the carrier and being adapted to be able to be compressed and expanded on demand.

Claims

1. A flexible light strip comprising, multiple solid state lighting units; and a flexible carrier that comprises conductive rails attached and electrically coupled to the multiple solid state lighting units and multiple buffer areas between adjacent solid state lighting units of the multiple solid state lighting units, each of the multiple buffer areas extending along a width of the flexible carrier from one edge to an opposite edge of the flexible carrier and adapted to be compressed and expanded.

2. The light strip as claimed in claim 1, wherein each of the multiple solid state lighting units is adjacent at least one of the buffer areas along a length of the light strip.

3. The light strip as claimed in claim 1, wherein each of the multiple buffer areas is shaped as a buckling area.

4. The light strip as claimed in claim 3, wherein a maximum height of each of the multiple buffer areas above an area of the flexible carrier between adjacent buffer areas of the multiple buffer areas defines a maximum local bending angle for the light strip relative to a linear shape of the light strip when non-bended.

5. The light strip as claimed in claim 3, wherein each of the multiple buffer areas is shaped as a gable roof comprising two roof sections sloping in opposite directions and located such that the highest edges meet to form a roof ridge.

6. The light strip as claimed in claim 1, wherein at least the multiple buffer areas are made of a ductile material.

7. (canceled)

8. An embossing tool comprising: at least one male sub-tool; and at least one female sub-tool, each of the at least one male sub-tool and the at least one female sub-tool comprising embossing surfaces facing towards each other, the embossing surfaces comprising at least one positive and one corresponding negative shape adapted to a demanded shape of a buffer area of a light strip that comprises multiple solid state lighting units, a flexible carrier for the multiple solid state lighting units and buffer areas within the flexible carrier between adjacent solid state lighting units of the multiple solid state lighting units and adapted to be compressed and expanded on demand.

9. The embossing tool as claimed in claim 8, wherein the at least one male and female sub-tools are shaped as rotatable cylindrical wheels with lateral surfaces as the embossing surfaces comprising multiple positive and corresponding negative shapes.

10. The embossing tool as claimed in claim 9, wherein diameters of the rotatable cylindrical wheels are adapted to provide releasing of a received pair of the positive and corresponding negative shapes simultaneously to receive a following pair of the positive and negative shapes in order to continuously feed the flexible carrier through the embossing tool.

11. A method (200) of manufacturing a light strip comprising multiple solid state lighting units, a flexible carrier for the solid state lighting units and buffer areas between adjacent solid state lighting units, the method comprising: providing a flexible pre-carrier that comprises a wiring and multiple flat pre-buffer areas along the flexible pre-carrier, separated from each other, and extending along a width of the flexible pre-carrier from one edge to an opposite edge of the flexible pre-carrier; providing an embossing tool for an embossing process, the embossing tool comprising a male sub-tool and a female sub-tool each comprising embossing surfaces facing towards each other, the embossing surfaces comprising at least one positive and one corresponding negative shape adapted to a demanded shape of the buffer area of the light strip; inserting at least the pre-buffer areas of the flexible pre-carrier into the embossing tool between the embossing surfaces; transferring the flat pre-buffer area into the demanded shape of the buffer area by the positive and corresponding negative shapes; and repeating the inserting and transferring for following non-treated pre-buffer areas of the flexible pre-carrier until all demanded buffer areas are shaped by the embossing process to be able to be compressed and expanded on demand.

12. The method as claimed in claim 11, further comprising attaching the solid state lighting units to the embossed flexible carrier.

13. The method as claimed in claim 11, wherein the flexible pre-carrier already carries one or more solid state lighting units between adjacent pre-buffer areas of the flexible pre-carrier before inserting the pre-buffer areas into the embossing tool.

14. The method as claimed in claim 11, wherein the male and female sub-tools are shaped as cylindrical wheels with lateral surfaces as the embossing surfaces comprising multiple positive and corresponding negative shapes located onto the embossing surfaces in order to receive each other during rotating the cylindrical wheels.

15. The light strip as claimed in claim 5, wherein a roof angle at the roof ridge is 90 degrees in a non-bended state of the light strip along a length of the light strip.

16. The embossing tool as claimed in claim 9, wherein the multiple positive and corresponding negative shapes are located on the cylindrical wheels such that they receive each other during rotation of the rotatable cylindrical wheels.

17. The method as claimed in claim 13, wherein the embossing surface of the male or female sub-tool comprises a recess suitable to receive the attached solid state lighting unit during embossing the pre-buffer areas.

18. The method as claimed in claim 13, wherein the inserting and transferring are executed by simultaneously rotating the cylindrical wheels with the flexible pre-carrier inserted between the cylindrical wheels.

19. The light strip as claimed in claim 1, wherein the conductive rails comprise two conductive rails.

20. The light strip as claimed in claim 19, wherein one of the two conductive rails defines the one edge of the flexible carrier and the other one of the two conductive rails defines opposite edge of the flexible carrier.

21. The light strip as claimed in claim 19, wherein the two conductive rails are configured for coupling to receive a drive current for the multiple solid state lighting units.

Description

BRIEF DESCRIPTION OF THE DRAWING(S)

[0040] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0041] The invention will now be described, by way of example, based on embodiments with reference to the accompanying drawings.

[0042] In the drawings:

[0043] FIG. 1 shows a principle sketch of a flexible light strip according to the present invention (a) in a side view, (b) in a top view in a non-bended status with a flexible foil as the carrier, and (c) in a top view in a non-bended status with a wiring as the carrier.

[0044] FIG. 2 shows a principle sketch of a flexible light strip according to the present invention (a) in a top view and (b) in a side view in a bended status with bending angle LBA.

[0045] FIG. 3 shows a principle sketch of an embodiment of an automotive light unit comprising a light strip according to the present invention.

[0046] FIG. 4 shows a principle sketch of an embodiment of an embossing tool to manufacture a light strip according to the present invention.

[0047] FIG. 5 shows a principle sketch of another embodiment of an embossing tool to manufacture a light strip according to the present invention.

[0048] FIG. 6 shows a principle sketch of an embodiment of the method according to the present invention.

[0049] In the Figures, like numbers refer to like objects throughout. Objects in the Figs. are not necessarily drawn to scale.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0050] Various embodiments of the invention will now be described by means of the Figures.

[0051] FIG. 1 shows a principle sketch of a flexible light strip 1 according to the present invention (a) in a side view, (b) in a top view in a non-bended status with a flexible foil 3 as the carrier 3, and (c) in a top view in a non-bended status with a wiring 31 as the carrier 3. The light strip 1 comprises multiple solid state lighting units 2 as light sources and a flexible carrier 3 for the solid state lighting units 2 attached to the flexible carrier 3. The light strip may have a length between a few centimeters up to several meters. For ease of understanding only a part of the light strip is shown here. It further comprises a suitable wiring 31 (see part (b)) connecting the solid state lighting units 2 to enable suitable driving of the solid state lighting units 2 to illuminate an environment with the flexible light strip 1. The flexible carrier 3 comprises multiple buffer areas 32 arranged between adjacent solid state lighting units 2 where each of the solid state lighting units 2 is followed by one buffer areas 32 along a length L of the light strip 1. The buffer areas 32 are shaped as a buckling area, here as a gable roof shape, in order to decrease the distance D between adjacent solid state lighting units 2 in a non-bended state of the light strip 1 along its length L. The gable roof shape of the buffer area 32 comprises two roof sections 321, 322 sloping in opposite directions and placed such that the highest edges meet to form a roof ridge 323. This gable roof shape is able to be expanded or compressed (see FIG. 2 for more details) The maximum height H of the buffer area 32 above the area 35 of the flexible carrier 3 between the buffer areas 32 defines the maximum local bending angle LBA for the light strip 1 relative to a linear shape of the light strip 1 when being non-bended provided by each buffer area 32. In this embodiment the roof angle RA at the roof ridge 323 provided by the two roof sections 321, 322 is essentially 90 degree in a non-bended state of the light strip 1 along its length L. The buffer areas 32 might be made of a ductile material. The buffer area 32 extends along a width W3 of the flexible carrier 3 from one edge 33 to the opposite edge 34 of the flexible carrier 3 in order to be bended along a bending axis BA perpendicular to the surface of the flexible foil. In FIG. 1b the carrier is a flexible foil 3 where the edges 33, 34 are the edges of the flexible foil 3. In FIG. 1c the carrier is established by the wiring 31 connecting the solid state lighting units 2, here established by conductive rails 31, where one rail 31 defines one edge 33 of the carrier 3 and the other rail 31 defines the other edge 34 of the carrier 3. Nevertheless both embodiments have the same side view as shown in FIG. 1a. The conductive rails may have any cross section shape suitable for the particular application. The rails (or wires) 31 may have diameters of 0.2 to 0.7 mm, typically of 0.4 mm. The rails 31 (or wires) may be made of copper, preferably coated with layers of nickel or gold.

[0052] FIG. 2 shows a principle sketch of a flexible light strip 1 according to the present invention (a) in a top view and (b) in a side view in a bended status with bending angle LBA. For ease of understanding, the embodiment shown in FIG. 2 shows a flexible foil 3 as the carrier 3. However the following also applies to the embodiments using conductive rails or (wires) as the carrier according to FIG. 1c without applying flexible foils. The maximum height H of the buffer area 32 above the area 35 of the flexible foil 3 between the buffer areas 32 defines the maximum local bending angle LBA for the light strip 1 relative to a linear shape of the light strip 1 when being non-bended provided by each buffer area 32. The local bending angle LBA is defined by the extended lines of the edge 33 of the flexible foil 3 extending from the buffer area 32 and from the area 35 between the buffer areas 32. The compressed side 33 of the buffer area 32 is the side facing towards the edge 33 of the flexible foil 3. The expanded side 34 of the buffer area 32 is the side facing towards the opposite edge 34 of the flexible foil 3. The compressed side 33 comprises gable roof shapes with roof sections 321, 322 having a steeper slope compared to the non-bended status. Correspondingly the height of the roof ridge 323 is larger and the roof angle RA is smaller compared to the non-bended status, as shown in FIG. 2b. The middle section of the bended buffer areas 32 remain at a gable roof shape with roof angel RA of approximately 90 degrees and the height H of the non-bended status. The expanded side 34 comprises gable roof shapes with roof sections 321, 322 having a less steep slope compared to the non-bended status. Correspondingly the height of the roof ridge 323 is smaller and the roof angle RA is larger compared to the non-bended status. Correspondingly the roof ridge 323 has a slope increasing from the expanded edge 34 to the compressed edge 33 of the flexible foil resulting in a bended flexible foil 3 (light strip 1) along the length of the flexible foil 3 (light strip 1). The maximum local bending angle LBA is achieved with a roof angle RA of 180 degrees at the expanded side 34 and with a roof angle of 0 degree at the compressed side 33.

[0053] FIG. 3 shows a principle sketch of an embodiment of an automotive light unit 10 comprising a light strip 1 according to the present invention. The light strip 1 is bended by more than 180 degrees over its entire length L in order to provide this particular design of the automotive light unit 100. The same initial light strip 1 might be bended differently in case of demanding differently shaped automotive light units 10. Therefore only one light strip 1 has to be manufactured for providing differently shaped automotive light units 10. The same holds also for light units applied for other purposes than automotive lighting when being equipped with a light strip 1 according to the present invention.

[0054] FIG. 4 shows a principle sketch of an embodiment of an embossing tool 100 to manufacture a light strip 1 according to the present invention. The embossing tool 100 comprises a male sub-tool 110 and a female sub-tool 120 each comprising embossing surfaces 130, 140 facing towards within the embossing tool 100, where the embossing surfaces 130, 140 comprise at least one positive shape 131 (male sub-tool) and one corresponding negative shape 141 (female sub-tool) adapted to a demanded shape of a buffer area 32 of the light strip 1, which comprises multiple solid state lighting units 2 as light sources, a flexible carrier 3 for the solid state lighting units 2 and suitably shaped buffer areas 32 within the flexible carrier 3 between adjacent solid state lighting units 2 to be able to be compressed C and expanded E on demand. Here the embossing process executed by the embossing tool 100 is schematically shown by the embossing tool 100 at three different stages of the embossing process. The process step shown in the left is during inserting the flexible pre-carrier 3p with a non-shaped buffer area 32p into the embossing tool 100, where male and female sub-tools 110, 120 are still separated from each other but just fixing the flexible pre-carrier 3p between the positive and negative shapes 131, 141. The step in the middle shows the embossing, where the shape of the pre-buffer area 32p is transferred 240 into the gable roof shape of the buffer area 32. The right step shows the male and female sub-tools 110, 120 and the positive and negative shapes 131, 141 being separated from each other in order to release the finished flexible carrier 3 with attached solid state lighting units 2 as light strip 1 from the embossing tool 100. Here the embossing surface 140 of the female sub-tool 120 comprises a recess 160 to receive the attached solid state lighting units 2 during embossing the pre-buffer areas 32p in order not to damage the solid state lighting units 2 during embossing.

[0055] FIG. 5 shows a principle sketch of another embodiment of an embossing tool 100 to manufacture a light strip 1 according to the present invention. In this embodiment the male and female sub-tools 110, 120 are shaped as rotatable cylindrical wheels 110, 120 with lateral surfaces as the embossing surfaces 130, 140 comprising multiple positive and corresponding negative shapes 131, 141, where the positive and negative shapes 131, 141 are suitable located onto the cylindrical wheels 110, 120 in order to receive each other during rotating the cylindrical wheels 110, 120. Here the diameters DW of the cylindrical wheels 110, 120 are suitably adapted to provide releasing of a received pair 150 of the positive and negative shapes 131, 141 simultaneously to receiving a following pair 150 of the positive and negative shapes 131, 141 in order to continuously feed the flexible carrier 3 through the embossing tool 100. In this case the total diameter of the female wheel 120 is larger than the diameter of the male wheel 110, because the female wheel 120 comprises a rim at the edges of the embossing surface 140 covering the positive shapes 131 of the male wheel 110 protruding from the embossing surface 130 of the male wheel 110.

[0056] FIG. 6 shows a principle sketch of an embodiment of the method 200 to manufacture a light strip 1 according to the present inventions as shown in FIGS. 1 and 2 in more details. The method 200 comprises the steps of providing 210 a flexible pre-carrier 3p as carrier for the solid state lighting units 2 comprising a wiring 31 suitable to connect the solid state lighting units 2 to enable suitable driving of solid state lighting units 2 when being attached to the carrier 3, wherein the flexible pre-carrier may comprises the solid state lighting units mounted onto the flexible pre-carrier or may be provided without solid state lighting units for later mounting, wherein the flexible pre-carrier 3p comprises multiple flat pre-buffer areas 32p along the flexible pre-carrier 3p separated from each other to enable placing of the solid state lighting units 2 in between the pre-buffer areas 32p, which extend along a width W3 of the flexible pre-carrier 3p from one edge 33 to the opposite edge 34 of the flexible pre-carrier 3p and providing 220 an embossing tool 100 (see FIGS. 4 and 5 for more details) for an embossing process comprising a male sub-tool 110 and a female sub-tool 120 each comprising embossing surfaces 130, 140 facing towards within the embossing tool 100, where the embossing surfaces 130, 140 comprise at least one positive and one corresponding negative shape 131, 141 adapted to the demanded shape of the buffer area 32 of the light strip 1 followed by inserting 230 at least the pre-buffer areas 32p of the flexible pre-carrier 3p into the embossing tool 100 between the embossing surfaces 130, 140, transferring 240 the flat pre-buffer area 32p into the demanded shape of the buffer area 32 by the positive and corresponding negative shapes 131, 141 receiving each during the embossing process, and repeating 250 the previous inserting and transferring steps 230, 240 for the following non-treated pre-buffer areas 32p of the flexible pre-carrier 3p until all demanded buffer areas 32 are shaped by the embossing process to be able to be compressed C and expanded E on demand. In case of the flexible pre-foil does not comprise the solid state lighting units the method further comprises the step of attaching 260 the solid state lighting units 2 to the embossed flexible carrier 3 in order to provide the light strip 1 equipped for illuminating the environment. In case of the flexible pre-carrier 3p already carries one or more solid state lighting units 2 between adjacent pre-buffer areas 32p of the flexible pre-carrier 3p before inserting 230 the pre-buffer areas 32p into the embossing tool 100 the embossing surface 130, 140 of the male or female sub-tool 110, 120 comprises a recess 160 suitable to receive the attached solid state lighting unit 2 during embossing the pre-buffer areas 32p in order not to damage the solid state lighting units during embossing.

[0057] In a further embodiment of the method the male and female sub-tools 110, 120 are shaped as cylindrical wheels 110, 120 with lateral surfaces as the embossing surfaces 130, 140 comprising multiple positive and corresponding negative shapes 131, 141 suitable located onto the embossing surfaces 130, 140 in order to receive each other during rotating the cylindrical wheels 110, 120, where the inserting and transferring steps 230, 240 are executed by simultaneously rotating the cylindrical wheels 110, 120 with the flexible pre-carrier 3p inserted between the cylindrical wheels 110, 120.

[0058] While the invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive.

[0059] From reading the present disclosure, other modifications will be apparent to persons skilled in the art. Such modifications may involve other features which are already known in the art and which may be used instead of or in addition to features already described herein.

[0060] Variations to the disclosed embodiments can be understood and effected by those skilled in the art, 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 of elements or steps. 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.

[0061] Any reference signs in the claims should not be construed as limiting the scope thereof.

LIST OF REFERENCE NUMERALS

[0062] 1 flexible light strip according to the present invention [0063] 2 solid state lighting unit(s), e.g. LED(s) [0064] 3 flexible carrier (e.g. flexible foil or conductive rails/wires) [0065] 3p flexible pre-carrier (e.g. flexible pre-foil or conductive pre-rails/pre-wires) [0066] 31 conductive rails as the carrier or wiring within the flexible foil as the carrier [0067] 32 buffer area(s) [0068] 32p pre-buffer area(s) [0069] 321 (first) roof section of a buffer area shaped as a gable roof [0070] 322 (second) roof section of a buffer area shaped as a gable roof [0071] 323 roof ridge, where both roof sections meet [0072] 33 one edge of the flexible carrier (compressed side) [0073] 34 opposite edge of the flexible carrier (expanded side) [0074] 35 area of the flexible carrier between the buffer areas [0075] 10 automotive light unit [0076] 100 embossing tool [0077] 110 male embossing sub-tool [0078] 120 female embossing sub-tool [0079] 130 embossing surface of the male sub-tool [0080] 131 positive shape adapted to the demanded shape of the buffer area [0081] 140 embossing surface of the female sub-tool [0082] 141 negative shape adapted to the demanded shape of the buffer area [0083] 150 pair of positive and negative shapes of the embossing surfaces [0084] 160 recess of male or female sub-tool to receive the solid state lighting unit attached to the flexible pre-carrier [0085] 200 method to manufacture a light strip [0086] 210 providing a flexible pre-carrier [0087] 220 providing an embossing tool for embossing the flexible pre-carrier [0088] 230 inserting the pre-buffer areas of the flexible carrier into the embossing tool [0089] 240 transferring the pre-buffer area into the demanded shape of the buffer area [0090] 250 repeating the previous inserting and transferring steps [0091] 260 attaching the solid state lighting units to the embossed flexible carrier [0092] BA bending axis [0093] C compressed buffer area, compression [0094] D distance between adjacent solid state lighting units [0095] DW diameter of cylindrical wheels as male and female sub-tools [0096] E expanded buffer area, expansibility [0097] H maximum height of the buckling area [0098] L length of the light strip [0099] LBA local bending angle of the light strip [0100] RA roof angle between both roof sections of the buffer area as a gable roof [0101] W3 width of the flexible carrier