Led light unit

Abstract

The present invention describes a LED light unit (1) for providing LED light, the LED light unit (1) comprising a flexible printed circuit board (PCB) (2) having a first longitudinal axis (LA1) and a plurality of elongated light sources (3) each having a second longitudinal axis (LA2). The plurality of elongated light sources (3) is arranged on the flexible PCB (2) such that none of the second longitudinal axes (LA2) of the plurality of elongated light sources (3) is parallel to the first longitudinal axis (LA1) of the flexible PCB (2). The LED light unit further comprises a carrier (4), wherein the flexible PCB (2) is bent along the first longitudinal axis (LA1) such that each of the elongated light sources (3) is arranged in the shape of a substantially circular arc, and wherein the flexible PCB (2) is subsequently at least partially attached to the carrier (4).

Claims

1. A LED light unit for providing LED light, said LED light unit comprising: a flexible printed circuit board (PCB) having a first longitudinal axis, a plurality of elongated light sources each having a second longitudinal axis, said plurality of elongated light sources being arranged on said flexible PCB such that none of the second longitudinal axes of said plurality of elongated light sources is parallel to said first longitudinal axis of said flexible PCB, said elongated light sources being arranged at a constant distance from each other, a spacing area being formed in said flexible PCB between each two elongated light sources, said spacing area being transparent due at least in part to removal of said flexible PCB in said spacing areas, and at least one of said elongated light sources having an encapsulant comprising a light scattering material configured to scatter LED light, and a carrier, wherein said flexible PCB is bent along said first longitudinal axis such that each of said elongated light sources is arranged in the shape of a substantially circular arc, wherein said flexible PCB is subsequently at least partially attached to said carrier, and wherein said carrier comprises a specular reflecting concave surface.

2. The LED light unit according to claim 1, wherein said elongated light sources being arranged on said flexible PCB are parallel to each other.

3. The LED light unit according to claim 1, wherein each of said circular arcs is lying in a plane being substantially perpendicular to the plane of said carrier.

4. The LED light unit according to claim 1, wherein a central angle of a circular sector defined by said substantially circular arc is at least 180 degrees.

5. The LED light unit according to claim 4, wherein said central angle of a circular sector defined by said substantially circular arc is between 200 and 360 degrees.

6. The LED light unit according to claim 1, wherein an angle between each of said second longitudinal axes of said elongated light sources and said first longitudinal axis of said flexible PCB is between 5 and 85 degrees.

7. The LED light unit according to claim 1, wherein each of said elongated light sources comprises a plurality of light emitting diodes (LEDs) providing LED light.

8. The LED light unit according to claim 1, wherein the encapsulant of the at least one elongated light source further comprises a luminescent material configured to at least partly convert LED light into converted light.

9. A lighting device comprising a LED light unit according to claim 1.

10. A method of manufacturing a LED light unit for providing LED light, said method comprising the steps of: a) providing a flexible printed circuit board (PCB) having a first longitudinal axis; b) providing a plurality of elongated light sources each having a second longitudinal axis, at least one of said elongated light sources having an encapsulant comprising a light scattering material configured to scatter LED light; c) arranging said plurality of elongated light sources on said flexible PCB such that (i) none of the second longitudinal axes of said plurality of elongated light sources is parallel to said first longitudinal axis of said flexible PCB, (ii) each of said elongated light sources has a constant distance from each other, and (iii) a spacing area is formed in said flexible PCB between each two elongated light sources by removing said flexible PCB in said spacing areas to cause the spacing area to be transparent; d) providing a carrier comprising a specular reflecting concave surface; e) bending said flexible PCB along said first longitudinal axis such that each of said elongated light sources is arranged in the shape of a substantially circular arc; f) at least partially attaching said flexible PCB to said carrier.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, of which:

(2) FIG. 1 is a perspective view of a LED light unit according to an exemplifying embodiment of the present invention;

(3) FIGS. 2a-2b is a side view of a LED light unit according to various exemplifying embodiments of the present invention;

(4) FIGS. 3a-3c are schematic views of a LED light unit according to further embodiments;

(5) FIGS. 4a-4c is a schematic view of a manufacturing process of a LED filament according to the present invention.

(6) All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate embodiments of the present invention, wherein other parts may be omitted or merely suggested.

DETAILED DESCRIPTION

(7) The present invention will now be described hereinafter with reference to the accompanying drawings, in which exemplifying embodiments of the present invention are shown. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments of the present invention set forth herein; rather, these embodiments of the present invention are provided by way of example so that this disclosure will convey the scope of the invention to those skilled in the art. In the drawings, identical reference numerals denote the same or similar components having a same or similar function, unless specifically stated otherwise.

(8) FIG. 1 illustrates a LED light unit 1 according to the present invention. The LED light unit 1 comprises a flexible printed circuit board (PCB) 2 having a first longitudinal axis LA1, a plurality of elongated light sources 3 each having a second longitudinal axis LA2. The plurality of elongated light sources 3 is arranged on the flexible PCB 2 such that none of the second longitudinal axes LA2 of the plurality of elongated light sources 3 is parallel to the first longitudinal axis LA1 of the flexible PCB 2. The LED light unit 1 further comprises a carrier 4, wherein the flexible PCB 2 is bent along the first longitudinal axis LA1 such that each of the elongated light sources 3 is arranged in the shape of a substantially circular arc, and wherein the flexible PCB 2 is subsequently attached to the carrier 4.

(9) As mentioned above, an advantage of the LED light unit 1 shown in FIG. 1 is that a spiral-like appearance is achieved by a simple structure, using separate relatively short elongated light sources 3 rather that one continuous LED filament that as to be arranged into a spiral shape by bending, folding, twisting or the like. Another advantage of the LED light unit 1 of the present invention is that the spiral-like appearance is achieved by a compact structure, requiring less space than a true spiral, which makes the LED light unit 1 of the present invention particularly suitable for use in flat lighting devices, such as luminaires, without compromising the aesthetical appearance.

(10) The PCB 2 has substantially rectangular shape. The first longitudinal axis LA1 runs parallel with the longitudinal extension of the PCB 2 through the central portion of the PCB 2.

(11) The LED light unit 1 comprises six elongated light sources 3. Each of the elongated light sources 3 comprises a LED filament 7 and a plurality of LEDs 6, supported by the LED filament 7. Each of the elongated light sources 3 shown in FIG. 1 further comprises an encapsulant 5.

(12) As is evident from FIG. 1, the LED light unit 1 resembles a shape of a spiral.

(13) As may be seen in FIG. 1, the plurality of the elongated light sources 3 are arranged on the flexible PCB 2 such that they are parallel to each other. Each circular arc is perpendicular to the plane of the carrier 4.

(14) Each two adjacent light sources 3 are arranged at a distance D1 from each other, such that a plurality of spacing areas A is formed in the flexible PCB 2. The distance D1 between each two adjacent elongated light sources 3 is constant. Such an arrangement further augments the spiral-like appearance of the LED light unit.

(15) As shown in FIG. 1, the spacing areas A formed in the flexible PCB 2 between each two elongated light sources 3 are transparent and are formed by removing the PCB material in the spacing areas, i.e. forming cut-outs between each two adjacent light sources 3. It should be noted that the PCB material is still present in circular arcs formed by the elongated light sources 3.

(16) The spacing areas A thus allow a higher degree of light transmission compared to the material of the flexible PCB 2.

(17) As shown in FIG. 1, the carrier 4 comprises a specular reflecting surface 8. In the embodiment shown in FIG. 1, the specular reflecting surface 8 is provided on the portion of the carrier surface arranged between the attachment portions of the flexible PCB 2. By providing such a specular reflecting surface 8, each of the elongated light sources 3 being in the shape of a circular arc in a manner disclosed above is reflected by the reflecting surface 8, thus creating a closed loop 9. Thus, the LED light unit 1 comprising such a specular reflecting surface 8 will have an enhanced spiral-shaped appearance. In order to improve the spiral-shaped appearance of the LED light unit 1 even further, the specular reflecting surface 8 of the carrier is concave.

(18) Thus, according to the present invention, the LED light unit 1 will be perceived as comprising a LED filament having a spiral shape, since each of the elongated light sources 3 will be arranged as a circular arc. On the other hand, the assembly of the LED light unit 1 of the present invention is significantly simplified and the cost is reduced compared to providing a true spiral.

(19) FIGS. 2a and 2b are schematic views of a cross-section of two different embodiments of LED light units 11, 21 according to the present invention. FIG. 2a depicts a LED light unit 11 comprising a flexible PCB 12 having a first longitudinal axis LA1 and one of the plurality of the elongated light sources 13 having a second longitudinal axis LA2. The LED light unit 11 further comprises a carrier 14, wherein the flexible PCB 12 is bent along the first longitudinal axis LA1 such that the elongated light source 13 is arranged in the shape of a substantially circular arc, and wherein the flexible PCB 12 is subsequently attached to the carrier 14. As may be seen in FIG. 2a, the central angle of a circular sector defined by the circular arc is 180 ( radian).

(20) FIG. 2b depicts another embodiment of the LED light unit 21 comprising a flexible PCB 22 having a first longitudinal axis LA1 and one of the plurality of the elongated light sources 23 having a second longitudinal axis LA2. The LED light unit 21 further comprises a carrier 24, wherein the flexible PCB 22 is bent along the first longitudinal axis LA1 such that the elongated light source 23 is arranged in the shape of a substantially circular arc, and wherein the flexible PCB 22 is subsequently attached to the carrier 24. As may be seen in FIG. 2b, the central angle of a circular sector defined by the circular arc is approximately 280 (1,6.Math. radian).

(21) In FIGS. 3a and 3b, a cross-sectional and top view, respectively, of another embodiment of the LED light unit is illustrated. The LED light unit 31 comprises a flexible PCB 32 having a first longitudinal axis LA1 and one of the plurality of the elongated light sources 33 having a second longitudinal axis LA2. The LED light unit 31 further comprises a carrier 34, wherein the flexible PCB 32 is bent along the first longitudinal axis LA1 such that the elongated light source 33 is arranged in the shape of a substantially circular arc, and wherein the flexible PCB 32 is subsequently attached to the carrier 34. The carrier 34 further comprises a specular reflecting surface 38 to which the flexible PCB 32 is attached. By providing such a specular reflecting surface 38, each of the elongated light sources 33 being in the shape of a circular arc in a manner disclosed above is reflected by the reflecting surface 38, thus creating a closed loop 39, as shown in FIG. 3b. Thus, the LED light unit 31 comprising such a reflecting surface 38 will have an enhanced spiral-shaped appearance.

(22) FIG. 3c shows yet another embodiment of the LED light unit 41, wherein the specular reflecting surface 48 of the carrier 44 is concave. Thus, the spiral-shaped appearance of the LED light unit 41 even further improved.

(23) FIGS. 4a-4c depict a method of manufacturing a LED light unit 51 for providing LED light according to present invention. FIG. 4a shows step a) of providing a flexible PCB 52 having a first longitudinal axis LA1, step b) of providing a plurality of elongated light sources 53 each having a second longitudinal axis LA2, and step c) of arranging the plurality of elongated light sources 53 on the flexible PCB 52 such that none of the second longitudinal axes LA2 of the plurality of elongated light sources 53 is parallel to the first longitudinal axis LA1 of the flexible PCB 52. In the particular embodiment shown in FIG. 4a, the angle between each of the second longitudinal axes LA2 of the elongated light sources 53 and the first longitudinal axis LA1 of the flexible PCB 52 is approximately 70. As may be seen in FIG. 4a, the plurality of the elongated light sources 53 are arranged on the flexible PCB 52 such that they are parallel to each other.

(24) Each two adjacent light sources 53 are arranged at a distance D1 from each other, such that a plurality of spacing areas A is formed on the flexible PCB 52. The distance D1 between each two adjacent elongated light sources 53 is constant. Such an arrangement further augments the spiral-like appearance of the LED light unit 51.

(25) As shown in FIG. 4b, the spacing areas A formed on the flexible PCB 52 between each two elongated light sources 53 are made transparent by removing the PCB material in the spacing areas, i.e. forming cut-outs between each two adjacent light sources 53.

(26) Finally, FIG. 4c illustrates step d) of providing a carrier 54, step e) of bending the flexible PCB 52 along its longitudinal axis LA1 such that each of the elongated light sources 53 is arranged in the shape of a substantially circular arc, and step f) of at least partially attaching the flexible PCB 52 to the carrier 54. As may be seen in FIG. 4c, each circular arc 53 is perpendicular to the plane of the carrier 54.

(27) Although the present invention has been described with reference to various embodiments, those skilled in the art will recognize that changes may be made without departing from the scope of the invention. It is intended that the detailed description be regarded as illustrative and that the appended claims including all the equivalents are intended to define the scope of the invention. While the present invention has been illustrated in the appended drawings and the foregoing description, such illustration is to be considered illustrative or exemplifying and not restrictive; the present invention is not limited to the disclosed 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 appended 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 claims should not be construed as limiting the scope.