LED LIGHTING DEVICE HAVING AN IMPROVED LED HOLDER

Abstract

A lighting device comprises a holder for LED filaments. The holder has a first electrically conductive holding structure and a second electrically conductive holding structure. Each holding structure comprises an essentially longitudinal connection section and an attachment section essentially perpendicular to the connection section.

Claims

1. A lighting device comprising a translucent bulb, a base having at least two electrical contacts, and a light engine arranged inside the bulb, the light engine comprising one or more LED filaments attached to a holder, the holder having a first holding structure that is electrically conductive and a second holding structure that is electrically conductive, wherein each LED filament is connected with a first end to the first holding structure and with a second end to the second holding structure, wherein the first holding structure is connected to a first electrical contact of the base and the second holding structure is connected to a second electrical contact of the base, characterized in that the first holding structure and the second holding structure each comprises an essentially longitudinal connection section and an attachment section essentially perpendicular to the connection section.

2. The lighting device according to claim 1, wherein at least one of the attachment section of the first holding structure and the attachment section of the second holding structure has a circular or a polygonal circumference.

3. The lighting device according claim 1, wherein at least one of the connection section of the first holding structure and the connection section of the second holding structure has the shape of a straight line.

4. The lighting device according to claim 1, wherein for at least one of the first holding structure and the second holding structure, the connection section is connected to the respective attachment section by a radial section.

5. The lighting device according to claim 4, wherein the radial section lies essentially in the plane of the respective attachment section.

6. The lighting device according to claim 4, wherein the radial section is arranged under an angle with respect to the plane of the respective attachment section.

7. The lighting device according to claim 1, wherein at least one of the first holding structure and the second holding structure is formed from a wire.

8. The lighting device according to claim 1, wherein the holder comprises a bridge element attached to the first holding structure and the second holding structure, wherein the bridge element is not electrically conductive.

9. The lighting device according to claim 8, wherein the bridge element comprises a front portion and a rear portion connectable to the front portion, wherein at least one of the front portion and the rear portion comprises grooves for accommodating the first holding structure and the second holding structure.

10. The lighting device according to claim 8, wherein at least one of the connection section of the first holding structure and the connection section of the second holding structure comprises an anti-rotation portion for preventing rotation of the bridge element around the respective holding structure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Preferred embodiments of the invention will be explained in the following, having regard to the drawings. It is shown in:

[0026] FIG. 1 a schematic view of an embodiment of a lighting device according to the present invention;

[0027] FIG. 2 a schematic view of an embodiment of a light engine of the lighting device according to FIG. 1;

[0028] FIG. 3 a schematic view of another embodiment of a light engine according to the present invention;

[0029] FIG. 4 a schematic view of the first holding structure of the light engine according to FIG. 3;

[0030] FIG. 5 a schematic view of the second holding structure of the light engine according to FIG. 3;

[0031] FIG. 6 a schematic view of the bridge of the light engine according to FIG. 3;

[0032] FIG. 7 a schematic view of a detail of another embodiment of a holding structure of a light engine according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0033] In the following, preferred embodiments of the invention will be described with reference to the drawings. The same or similar elements or elements having the same effect may be indicated by the same reference number in multiple drawings. Repeating the description of such elements may be omitted in order to prevent redundant descriptions.

[0034] FIG. 1 shows a schematic view of an embodiment of a lighting device according to the present invention. An enlarged view of the light engine is shown in FIG. 2. The lighting device (in this case a retrofit lamp (hereinafter referred to simply as lamp), suitable for replacing known incandescent lamps) comprises a glass bulb 1, a light engine 5 arranged inside the bulb 1, and a lamp base 2 with an Edison type screw base. In order to enhance thermal dissipation and prolong the life of the lamp, the bulb can be filed with a gas having high thermal conductivity. Preferably, the gas contains helium and/or hydrogen.

[0035] The light engine comprises a holder having a first holding structure 14 and a second holding structure 15. Both holding structures are made from a wire (e.g. nickel plated stainless steel with a diameter between approximately 0.8 mm to approximately 2.5 mm) by bending the wire into the shape of the holding structure. The first holding structure 14 comprises an annular attachment section 17 which is attached to its connection section 9 via a radial section 18. The attachment section 17 is arranged essentially perpendicular to the straight connection section 9. The radial section 18 lies essentially in the plane of the attachment section 17. The lower end of the connection section 9 is fixedly held by a glass stem 33.

[0036] The stem 33 comprises a flange 33a, two lead wires 33b and a glass tube 33c. During production of the lamp, the bulb 2 can be evacuated and filled with a gas having high thermal conductivity through the tube 33c which is then closed by melting.

[0037] The second holding structure 15 comprises an annular attachment section 20 which is attached to its connection section 9 via a radial section 21. The attachment section 20 is arranged essentially perpendicular to the straight connection section 9. The radial section 21 lies essentially in the plane of the attachment section 20. The lower end of the connection section 9 is fixedly held by a glass stem 33.

[0038] In both attachment sections 17,20 the end of the wire lies next to the point where the attachment section 17,20 meets the corresponding radial section 18,21.

[0039] Since both holding structures 14,15 are made by bending a single wire, their production can easily be integrated into an automated production line. No soldering or welding is necessary for the production of the holding structures. Nevertheless, the completed holder is strong enough to support the LED filaments.

[0040] The LED filaments 12 are electrically conductively attached with their electrical contacts 13 to the attachment sections 17,20 of both holding structures 14,15, e.g. by soldering or welding.

[0041] The LED filaments are connected in parallel such that the LED filaments work independently from each other. Accordingly, even if one of the LED filaments should fail, the lamp is still able to operate, thus prolonging the life of the lamp.

[0042] FIG. 3 shows a schematic view of another embodiment of a light engine according to the present invention. Details of this embodiment are shown in FIGS. 4-7. The holder of the light engine shown in FIG. 3 comprises a first holding structure 14 and a second holding structure 15. Both holding structures are made from a wire (e.g. nickel plated stainless steel with a diameter between approximately 0.8 mm to approximately 2.5 mm) by bending the wire into the shape of the holding structure. A bridge 16 is attached to both holding structures 14,15 and stabilizes the holder.

[0043] The first holding structure 14 comprises an annular attachment section 17 which is attached to its connection section 9 via a radial section 18. The attachment section 17 is arranged essentially perpendicular to the straight upper portion of the connection section 9. The radial section 18 lies essentially in the plane of the attachment section 17.

[0044] The connection section 9 includes a zig-zag bend 19, i.e. two bends of approximately 90. The two bends of the zig-zag bend 19 are arranged such that the upper portion of connection section 9 and the lower portion of connection section 9 are essentially parallel to each other. In other words, the upper portion of connection section 9, the lower portion of connection section 9, and the zig-zag bend 19 essentially lie in the same plane. The end of the lower portion of connection section 9 is bent by an angle of approximately 45, thus resulting in a fixation element 10 which serves for attaching the light engine 5 to connectors held for example by a glass stem.

[0045] The second holding structure 15 comprises an annular attachment section 20 which is attached to its connection section 9 via a radial section 21. The attachment section 20 is arranged essentially perpendicular to the straight connection section 9. The radial section 21 lies essentially in the plane of the attachment section 20. The end of the lower portion of connection section 9 is bent by an angle of approximately 45, thus resulting in a fixation element 10 which serves for attaching the light engine 5 to connectors held for example by a glass stem.

[0046] In both attachment sections 17,20 the end of the wire runs parallel to a portion of the attachment section 17,20. The end of the wire can include a S-shaped bend next the point where the attachment section 17,20 meets the corresponding radial section 18,21 so that the end of the wire lies slightly below (alternatively above, inside, or outside) the attachment section 17,20. The end of the wire may be electrically conductively connected to the respective attachment section 17,20.

[0047] The bridge 16 is shown in an unmounted state in FIG. 6. The bridge 16 comprises a front portion 23 and a rear portion 22 connected to each other by a flexible hinge element 24. The rear portion 22 comprises two channels 25. The depth of the channels 25 is approximately equal to or greater than the thickness of the wire from which the holding structure 14,15 are made. Both channels 25 have an angle of approximately 90. Thus, the zig-zag bend 19 of the first holding structure 14 and the 90 bend at the inner end of the radial portion 21 of the second holding structure 15 can be received by the channels 25. Thereafter, the front portion 23 of the bridge 16 can be moved over the rear portion 22 and can be fixed to the rear portion 22 by means of latches 26 on the front portion 23 engaging window 27 in the rear portion 22. Thus, bridge 16 is closed and fixates the two holding structures 14,15 with respect to each other. The bridge 16 is made from an electrically non-conductive plastic material (e.g. by injection molding), isolating the two holding structures 14,15 from each other. Since the part of the zig-zag bend 19 of the first holding structure and the 90 bend of the second holding structure are covered by the bridge 16, rotation of the bridge 15 with respect to either holding structure 14,15 is prevented.

[0048] FIG. 7 shows schematically another embodiment of an upper portion of the first holding structure 14. An upper portion of the second holding structure 15 could also be designed in this alternative form. In this alternative embodiment, the radial section 28 does not lie in the plane of the attachment section 17, but rather at an angle to the plane downwards and inwards. The end of the wire does not run along the attachment section 17 (as shown in FIG. 6) but along the radial section 28. The end of the wire may be electrically conductively connected to the radial section 28.

[0049] While the above holding structure have been described as being bent from a single wire, it is also possible to bend two or more portions of one or both holding structures of a holder separately and attach them to each other, e.g. by soldering or welding. For example, a first wire section can be bent into a circle (attachment section) and a second wire portion can be bent into an L-shape (radial section and connection section). The end of one arm of the L can then be welded to the circle to obtain a holding structure as shown above in FIGS. 1 and 2. Other separations of a holding structure into portions to be bent separately are also envisioned by the invention.

[0050] Although the invention has been illustrated and described in detail by the explained embodiments, it is not limited to these embodiments. Other variations may be derived by the skilled person without leaving the scope of the attached claims.

[0051] Generally, a or an may be understood as singular or plural, in particular with the meaning at least one, one or more, etc., unless this is explicitly excluded, for example by the term exactly one, etc.

[0052] In addition, numerical valued may include the exact value as well as a usual tolerance interval, unless this is explicitly excluded.

[0053] Features shown in the embodiments, in particular in different embodiments, may be combined or substituted without leaving the scope of the invention.

LIST OF REFERENCE NUMBERS

[0054] 1 bulb [0055] 2 base [0056] 5 light engine [0057] 9 connection section [0058] 10 fixation element [0059] 12 LED filament [0060] 13 electrical contact of LED filament [0061] 14 first holding structure [0062] 15 second holding structure [0063] 16 bridge [0064] 17 attachment section of first holding structure [0065] 18 radial section of first holding structure [0066] 19 zig-zag bend [0067] 20 attachment section of second holding structure [0068] 21 radial section of second holding structure [0069] 22 rear portion of bridge [0070] 23 front portion of bridge [0071] 24 hinge element [0072] 25 channel [0073] 26 latch [0074] 27 window [0075] 33 glass stem [0076] 33a flange [0077] 33b lead wire [0078] 33c glass tube