LED FILAMENT COMPRISING LEDS ARRANGED TO EMIT VIOLET AND UV LIGHT

Abstract

There is provided a light emitting diode, LED, filament, configured to emit LED filament light (105). The LED filament comprises an elongated carrier (110) extending in a first direction, A, comprising a first surface (112) and a second surface (114) oppositely arranged the first surface. The LED filament further comprises a first linear array (120) of a plurality of first light emitting diodes, LEDs, arranged on the first surface, wherein the plurality of first LEDs is arranged to emit ultra-violet, UV, light (121) with a first centroid wavelength, Xc1, in a wavelength range of 100-380 nm. The LED filament further comprises a second linear array (130) of a plurality of second LEDs, arranged on the second surface, wherein the plurality of second LEDs is arranged to emit violet light (131) with a second centroid wavelength, Xc.sub.2, in a wavelength range of 380-420 nm.

Claims

1. A light emitting diode, LED, filament, configured to emit LED filament light, comprising: an elongated carrier extending in a first direction, A, comprising a first surface and a second surface oppositely arranged the first surface, a first linear array of a plurality of first light emitting diodes, LEDs, arranged on the first surface, wherein the plurality of first LEDs is arranged to emit ultra-violet, UV, light with a first centroid wavelength, .sub.C1, in a wavelength range of 100-380 nm, a second linear array of a plurality of second LEDs, arranged on the second surface, wherein the plurality of second LEDs is arranged to emit violet light with a second centroid wavelength, .sub.C2, in a wavelength range of 380-420 nm, and wherein the first linear array comprises a number, N.sub.1, of first LEDs, and the second linear array comprises a second number, N.sub.2, of second LEDs, wherein N.sub.1<=0.5.Math.N.sub.2.

2. The LED filament according to claim 1, wherein the first and second linear arrays extend in a direction parallel with the first direction, A.

3. The LED filament according to claim 1, further comprising a first encapsulant at least partially enclosing the second linear array of the plurality of second LEDs, wherein the first encapsulant comprises a light scattering material configured to scatter at least part of the violet light emitted from the plurality of second LEDs.

4. The LED filament according to claim 3, wherein the elongated carrier is light transmissive, and wherein the light scattering material is arranged to scatter at least a part of the violet light through the elongated carrier.

5. The LED filament according to claim 1, further comprising a second encapsulant at least partially enclosing the second linear array of the plurality of second LEDs, wherein the second encapsulant comprises a reflective layer arranged on the second encapsulant to reflect at least part of the violet light emitted from the plurality of second LEDs.

6. The LED filament according to claim 5, wherein the elongated carrier is light transmissive, and wherein the reflective layer is arranged to reflect at least a part of the violet light through the elongated carrier.

7. The LED filament according to claim 4, wherein one of the first encapsulant is configured to scatter at least 55% of the violet light through the elongated carrier, and the second encapsulant is configured to reflect at least 55% of the violet light through the elongated carrier, is fulfilled.

8. The LED filament according to claim 1, further comprising a third encapsulant at least partially enclosing the first linear array of the plurality of first LEDs, wherein the third encapsulant is light transmissive.

9. The LED filament according to claim 1, wherein the number of first LEDs, N.sub.1, per unit length, L.sub.1, of the first linear array and the number of second LEDs, N.sub.2, per unit length, L.sub.2, of the second linear array fulfil N.sub.1/L.sub.1<0.5.Math.N.sub.2/L.sub.2.

10. The LED filament according to claim 1, wherein the second centroid wavelength, .sub.C2, is in a wavelength range of 400-410 nm, and/or the first N.sub.1 centroid wavelength, .sub.C1, is in a wavelength range of 100-280 nm.

11. A LED filament arrangement, comprising, at least one LED filament according to claim 1, a controller coupled to the set of linear arrays, wherein the controller is configured to individually control the operation of the first linear array and the second linear array, and at least one of a user interface coupled to the controller, wherein the controller is configured to be controlled by an operator via the user interface, and a sensor coupled to the controller, wherein the sensor is configured to register sensor data and wherein the controller is configured to individually control the operation of the respective linear array of the set of linear arrays based on the sensor data.

12. The LED filament arrangement according to claim 11, wherein the sensor is configured to detect at least one of the presence of at least one person and the distance of a person to the sensor.

13. A tubular lighting device, comprising at least one of the LED filament according to claim 1, the tubular lighting device further comprising a tubular housing comprising a first end cap at a first end of the tubular housing, and a second end cap at a second end of the tubular housing, opposite the first end of the tubular housing, wherein the first and second end caps comprise a first pair and second pair of pins, respectively.

14. The tubular lighting device according to claim 13, further comprising a fixture having first and second connectors, wherein the first pair and second pair of pins of the tubular housing are configured for mating connection to the first and second connectors, respectively, for mechanical and electrical connection between the tubular housing and the fixture.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiment(s) of the invention.

[0039] FIG. 1a schematically show a cross-section from a side-view of a LED filament according to an exemplifying embodiment of the present invention,

[0040] FIG. 1b schematically disclose distributions of LED light of the LED filament according to an exemplifying embodiment of the present invention,

[0041] FIGS. 2a-b schematically show a top view and bottom view of a LED filament according to exemplifying embodiments of the present invention,

[0042] FIGS. 3 and 4 schematically show cross sections, in the longitudinal direction, of a LED filament according to exemplifying embodiments of the present invention,

[0043] FIG. 5 schematically shows a LED filament arrangement according to an exemplifying embodiment of the present invention, and

[0044] FIG. 6 shows a tubular LED device according to exemplifying embodiments of the present invention.

DETAILED DESCRIPTION

[0045] FIG. 1a schematically show a cross-section from a side-view of a LED filament 100 according to exemplifying embodiments of the present invention. The LED filament 100 is configured to emit LED filament light 105. The LED filament 100 comprises an elongated carrier 110 extending in a first direction, A. The elongated carrier 110 comprises a first surface 112 and a second surface 114, wherein the second surface is oppositely arranged the first surface 112. The first 112 and second surface 114 may be the front side and back side of an elongated and relatively flat carrier. The LED filament 100 further comprises a first linear array 120 of a plurality of first LEDs arranged on the first surface 112. The plurality of first LEDs is arranged to emit UV light with a first centroid wavelength, .sub.C1, in a wavelength range of 100-380 nm. The LED filament 100 further comprises a second linear array 130 of a plurality of second LEDs arranged on the second surface 114. The plurality of second LEDs is arranged to emit violet light with a second centroid wavelength, .sub.C2, in a wavelength range of 380-420 nm.

[0046] FIG. 1b schematically disclose distributions of the LED light, provided by the LED filament, with intensity (y-axis, arb. units) as a function of wavelength (x-axis, arb. units). The UV light 121 has a first centroid wavelength, .sub.C1, in a wavelength range of 100-380 nm, and the violet light 131 has a second centroid wavelength, .sub.C2, in a wavelength range of 380-420 nm. The first centroid wavelength, .sub.C1, may be in a wavelength range of 100-280 nm. The second centroid wavelength, .sub.C2, may be in a wavelength range of 400-410 nm. It is to be understood that the intensities I.sub.1 and I.sub.2 may be the same or different.

[0047] FIG. 2a-b schematically show a top view and a bottom view of a LED filament 100 according to exemplifying embodiments of the present invention. The LED filament 100 comprises an elongated carrier 110. The LED filament 100 further comprises a first linear array 120 arranged on a first surface 112 of the elongated carrier 110, and a second linear array 130 arranged on a second surface 114 of the elongated carrier 110. The first linear array 120 comprises a plurality of first LEDs arranged to emit UV light 121 with a first centroid wavelength, .sub.C1, in wavelength range of 100-380 nm. The second linear array 130 comprises a plurality of second LEDs arranged to emit violet light 131 with a second centroid wavelength, .sub.C2, in a range of 380-420 nm.

[0048] In FIG. 2a the first linear array 120 comprises N.sub.1 first LEDs distributed along the elongated carrier 110 per unit length L.sub.1, arranged on the first surface 112. In FIG. 2b the second linear array 130 comprises N.sub.2 first LEDs distributed along the elongated carrier 110 per unit length L.sub.2, arranged on the first surface 114. The second linear array 130 may have a higher number of LEDs, N.sub.1<N.sub.2, and/or a higher number of LEDs per unit length, N.sub.1/L.sub.1<N.sub.2/L.sub.2, compared to the first linear array 120. For example, the number of first LEDs, N.sub.1, and the number of second LEDs, N.sub.2, may fulfil N.sub.1<=0.5.Math.N.sub.2. In addition and/or alternatively, the number of first LEDs, N.sub.1, per unit length, L.sub.1, of the first linear array and the number of second LEDs, N.sub.2, per unit length, L.sub.2, of the second linear array may fulfil N.sub.1/L.sub.1<0.5.Math.N.sub.2/L.sub.2. The plurality of first LEDs may comprise at least 5 LEDs, preferably at least 10 LEDs, more preferably at least 15 LEDs, most preferably at least 20 LEDs. The plurality of second LEDs may comprise at least 10 LEDs, preferably at least 20 LEDs, more preferably at least 30 LEDs, most preferably at least 40 LEDs.

[0049] FIG. 3 schematically shows a cross section in the longitudinal direction of a LED filament 100 according to exemplifying embodiments of the present invention. It should be noted that the LED filament 100 shown in FIG. 3 has several features in common with the LED filament 100 shown in FIGS. 1a and 2a-b, and it is hereby referred to FIG. 1a, 2a-b and the associated texts for an increased understanding of some of the features and/or functions of the LED filament 100. The LED filament 100 comprises an elongated carrier 110, wherein a first linear array 120 is arranged on the first surface 112 of the elongated carrier 110 and a second linear array 130 is arranged on the second surface 114 of the elongated carrier 110. The elongated carrier 110 is light transmissive. The LED filament 100 further comprises a first encapsulant 140. The first encapsulant 140 at least partially encloses the second linear array 130. The first encapsulant 140 may fully enclose the second linear array 130. Consequently, the first encapsulant 140 may enclose the second surface 114, partially or fully. The first encapsulant 140 comprises a light scattering material and/or a reflective layer. The light scattering material 140 is configured to scatter at least part of the violet light 131 from the second LEDs, wherein the scattered violet light 131 may be scattered through the light transmissive elongated carrier 110. The reflective layer is arranged to reflect at least part of the violent light 131 through the elongated carrier 110. The first encapsulant 140 may be configured to, if the first encapsulant 140 comprises a light scattering material, scatter at least 55% of the violet light through the elongated carrier 110. The first encapsulant 140 may be configured to, if the first encapsulant 140 comprises a reflective layer, reflect at least 55% of the violet light through the elongated carrier 110.

[0050] FIG. 4 schematically shows a cross section in the longitudinal direction of a LED filament according to exemplifying embodiments of the present invention. It should be noted that the LED filament 100 shown in FIG. 4 has several features in common with the LED filament 100 shown in FIGS. 1a, 2a-b and 3, and it is hereby referred to FIG. 1a, 2a-b, 3 and the associated texts for an increased understanding of some of the features and/or functions of the LED filament 100. The LED filament 100 comprises an elongated carrier 110, a first 120 and second linear array 130 arranged on a first 112 and second surface 114, respectively, of the elongated carrier 110. The LED filament 100 comprises a first encapsulant 140 at least partially enclosing the second linear array 130. In FIG. 4, the LED filament further comprises a third encapsulant 150. The third encapsulant 150 encloses, partially or fully, the first linear array 120 of the plurality of first LEDs. The third encapsulant 150 is light transmissive. The third encapsulant 150 may be free from light scattering material.

[0051] FIG. 5 schematically shows a LED filament arrangement 200 according to exemplifying embodiments of the present invention. The LED filament arrangement 200 comprises at least one LED filament 100 according to an embodiment of the present invention. The LED filament arrangement 200 may comprise a plurality of LED filaments 100. It should be noted that the LED filament 100 shown in FIG. 5 has several features in common with the LED filament 100 shown in FIGS. 1a, 2a-b, 3 and 4, and it is hereby referred to FIG. 1a, 2a-b, 3, 4 and the associated texts for an increased understanding of some of the features and/or functions of the LED filament 100.

[0052] The LED filament arrangement 200 further comprises a controller 210 coupled to the set of linear arrays of the at least one LED filament 100. The set of linear arrays may be the group comprising the first and second linear array(s). The controller 210 is configured to individually control the operation of the first linear array and the second linear array. The LED filament arrangement 200 further comprises a user interface 300 coupled to the controller 210, wherein the controller 210 is configured to be controlled by an operator via the user interface 300, and/or a sensor 310 coupled to the controller, wherein the sensor is configured to register sensor data and wherein the controller 210 is configured to individually control the operation of the respective linear array of the set of linear arrays based on the sensor data. The sensor 310 may be configured to detect at least one of the presence of at least one person and the distance of a person to the sensor.

[0053] In an embodiment there is provided a luminaire 300. The luminaire 300 comprises at least one LED filament 100 according to an embodiment of the present invention. The luminaire 300 comprises a light transmissive cover 310 at least partially enclosing the at least one LED filament 100, and an electrical connection 320 connected to the at least one LED filament 100 for a supply of power to the plurality of LEDs of the at least one LED filament 100. The LED filament arrangement 200 may comprise the luminaire 300.

[0054] FIG. 6 shows a tubular LED device 400 according to exemplifying embodiments of the present invention. The tubular LED device, TLED, 400 comprises a LED filament 100 according to an embodiment of the present invention and/or a LED filament arrangement according to an embodiment of the present invention. The TLED 400 further comprises a tubular housing 405. The tubular housing 405 comprises a first end cap 410 arranged at a first end of the tubular housing 405, and a second end cap 415 at a second end of the tubular housing 405. The first and second end caps 410, 415 comprise a first pair and second pair of pins 420a, 420b, respectively. The TLED device 400 further comprises a fixture 440. The fixture 440 comprises first and second connectors 445a, 445b, wherein the first pair and second pair of pins 420a, 420b of the tubular housing 405 are configured for mating connection to the first and second connectors 420a, 420b, respectively, for mechanical and electrical connection between the tubular housing 405 and the fixture 440.

[0055] 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. For example, one or more of the LED filament 100, the elongated carrier 110, the LEDs, etc., may have different shapes, dimensions and/or sizes than those depicted/described.