Flexible light-emitting diode lighting strip with interposer

Abstract

The invention describes a flexible lighting strip comprising a multitude of light-emitting diodes arranged in at least two groups. Each group comprises at least two light-emitting diodes arranged in an electrical series connection. The at least two groups are arranged in parallel to an anode track and a cathode track. The at least two groups are arranged in a longitudinal arrangement such that a last light-emitting diode of a first group is arranged next to a first light-emitting diode of a second group. The anode track and the cathode track each consist of a wire line having substantially circular wires that are bent to receive compressive and/or tensile stress. The electrical circuit provides a third wire line having a substantially circular wire as a center line arranged between the outer lines. At least one light-emitting diode of every group is mounted on an interposer which contracts all three wire lines.

Claims

1. A flexible lighting strip comprising: a first group of serially connected light-emitting diodes including one interposer of a plurality of interposers for each of the light-emitting diodes; a second group of serially connected light-emitting diodes including one interposer of the plurality of interposers for each of the light-emitting diodes, the second group of serially connected light-emitting diodes in a longitudinal arrangement with the first group such that a last light-emitting diode of the first group is next to a first light-emitting diode of the second group, the first group and the second group being electrically parallel; an anode track and a cathode track arranged substantially parallel to the longitudinal arrangement and providing electrical connection to the first group and to the second group in parallel, the anode track and the cathode track including a wire having a substantially circular cross section being bent; a third wire line including a wire having a substantially circular cross section at a center line arranged between and approximately parallel to the anode track and the cathode track; and the plurality of interposers, each of which has electrical coupling pads on both sides thereof to electrically connect with the at least one light-emitting diode mounted thereon, the anode track, the cathode track and the third wire line, providing electrical connection to the mounted light-emitting diode.

2. The flexible lighting strip according to claim 1, wherein the interposer has two electrical coupling pads on a first side for connection to the light-emitting diode.

3. The flexible lighting strip according to claim 2, wherein the interposer has four coupling pads on a second side for connection to the wires.

4. The flexible lighting strip according to claim 3, wherein the two coupling pads on the first side of the interposer are connected to two of the coupling pads of the second side of the interposer via vias.

5. The flexible lighting strip according to claim 1, wherein the anode track and the cathode track point outwards in one plane.

6. The flexible lighting strip according to claim 5, wherein the third wire line has at least one bent wire segment protruding from the plane defined by the anode track and the cathode track.

7. The flexible lighting strip according to claim 5, wherein the third wire line has at least one bent wire segment perpendicular to the plane defined by the anode track and the cathode track.

8. The flexible lighting strip according to claim 1, wherein three light-emitting diodes are connected in series between the anode track and the cathode track, a first light-emitting diode connects the anode track to a first inner segment of the third wire line, and the first inner segment connects via a second light-emitting diode to a second inner segment of the third wire line, and the second inner segment connects via a third light-emitting diode to the cathode track.

9. The flexible lighting strip according to claim 1, wherein all light emitting diodes are mounted on interposers.

10. The flexible lighting strip according to claim 1, wherein a routing for electrical connection is different for at least two interposers in the group.

11. The flexible lighting strip according to claim 1, wherein at least one group of two or more light-emitting diodes and three different kinds of interposers with varied electrical routings are integrated.

12. The flexible lighting strip according to claim 1, wherein the third wire line has a substantially circular wire that is segmented.

13. The flexible lighting strip according to claim 1, wherein the third wire line is substantially made from straight wire segments.

14. The flexible lighting strip according to claim 1, wherein the third wire line is substantially made from bent wire segments.

15. The flexible lighting strip according to claim 1, wherein the interposer is made out of a printed Circuit Board (PCB).

16. The flexible lighting strip according to claim 1, wherein the interposer is made out of a ceramic material.

17. The flexible lighting strip according to claim 1, wherein one of the interposers is positioned at one outer end of all groups and is connected to an external power line.

18. The flexible lighting strip according to claim 1, wherein the light-emitting diode and the wire are soldered to the interposer, and at least one solder point is double re-flown.

19. A vehicle light assembly comprising the flexible lighting strip according to claim 1, wherein the vehicle light assembly comprises an electrical interface and the electrical interface is arranged to couple the vehicle light assembly to an external power supply.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

(2) The invention will now be described, by way of example, based on embodiments with reference to the accompanying drawings. In the drawings:

(3) FIG. 1 shows a side view of three SMD light-emitting diodes on an interposer.

(4) FIG. 2 shows a top view of three SMD light-emitting diodes on an interposer with light-emitting diodes mounted.

(5) FIG. 3 shows a top view top view of three SMD light-emitting diodes on an interposer with light-emitting diodes removed.

(6) FIG. 4 shows a top view of three SMD light-emitting diodes on an interposer, cut at wire pad level.

(7) FIG. 5 shows a top view of three SMD light-emitting diodes on an interposer with light-emitting diodes mounted.

(8) FIG. 6a shows the build-up of a longer group of three in line light-emitting diodes.

(9) FIG. 6b shows the electrical scheme of light-emitting diode string of FIG. 6a.

(10) FIGS. 7a, 7b, and 7c show potential shapes of the connecting wire.

(11) In the Figures, like numbers refer to like objects throughout. Objects in the Figs. are not necessarily drawn to scale.

DETAILED DESCRIPTION OF EMBODIMENTS

(12) Various embodiments of the invention will now be described by means of the Figures.

(13) FIG. 1 shows a side view of a group of three SMD light-emitting diodes 22 on an interposer 24 as section of a flexible light-emitting diode band with multitude of light-emitting diodes in a longitudinal arrangement. The light-emitting diodes 22 are connected in an electrical series connection in line by wire 30 and as a group in parallel to other three light-emitting diodes groups.

(14) FIG. 2 shows a top view of three SMD light-emitting diodes 22 on interposers 24 with light-emitting diodes 22 mounted as section of a flexible light-emitting diode band with multitude of light-emitting diodes in a longitudinal arrangement. The light-emitting diodes 22 are arranged in an electrical circuit having at least an anode track 12 and a cathode track 14 as outer lines 12, 14. Each of the outer lines 12, 14 consists of a wire line having substantially circular wires 30, whereby the wires of the outer lines 12, 14 are bent to receive compressive and/or tensile stress. The electrical circuit provides a third wire line 15 having a substantially circular wire 30 as a center line arranged between the outer lines 12, 14. The interposers 24 contact all three wire lines 12, 14, 15.

(15) FIG. 3 shows a top view of three SMD light-emitting diodes 22 on an interposer 24 with light-emitting diodes 22 removed as section of a flexible light-emitting diode band with multitude of light-emitting diodes in a longitudinal arrangement. The interposers 24 have two electrical coupling pads 3 on a first side for connection to the light-emitting diodes 22. Thereby, anode pad 3 and cathode pad 3 differ to correctly orient the light-emitting diodes 22. Since the light-emitting diodes 22 are removed, the electric coupling pads 3 are made visible. The electric coupling pads 3 connect to wire pads on the bottom of the interposers 24 via vias (not shown).

(16) FIG. 4 shows a top view of three SMD light-emitting diodes 22 on interposers 24, cut at wire pad level, as section of a flexible light-emitting diode band with multitude of light-emitting diodes in a longitudinal arrangement. The coupling pads (3, 3a, 3b) for the electrical connection are shown as squares. The hatched coupling pads 3a connect with the top surface of the interposer 24 via vias (not shown). The non-current carrying coupling pads 3b do not carry current and have only a mechanical function.

(17) FIG. 5 shows a top view of three SMD light-emitting diodes 22 on interposers 24 as section of a flexible light-emitting diode band with multitude of light-emitting diodes 22 in a longitudinal arrangement. The electrical connection of the light-emitting diodes 22 is schematically included. In the flexible lighting strip 100, three light-emitting diodes 22 are connected in series between the outer lines 12, 14. A first light-emitting diode 22 is connected to the cathode track 14 to a first inner segment, the first inner segment is connected via a second light-emitting diode 22 to a second inner segment, and the second inner segment is connected via a third light-emitting diode to the anode track 12. The outer lines 12, 14 are continued, however the inner line which is the third wire line 15 is segmented. Moreover, the wire 30 of the third wire line 15 is composed of straight segments.

(18) FIG. 6a shows the build-up of a longer group of three in line light-emitting diodes 22.

(19) FIG. 6b shows the electrical scheme of light-emitting diode string of FIG. 6a.

(20) FIGS. 7a, 7b, and 7c show potential shapes of the wire 30 used in the outer lines 12, 14. The shapes shown in FIG. 7b and FIG. 7c are more suited as they can compensate compressive and tensile stress. Using a circular form of the wire 30, forces imposed on the flexible lighting strip 100 during thermomechanical cycle stress testing are withstood and absorbed better as it can be done by a square lead frame line.

(21) 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.

(22) 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.

(23) 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.

(24) Any reference signs in the claims should not be construed as limiting the scope thereof.