T-LED AIR INCLUDED LIGHT TUBE

Abstract

The invention provides a light generating device (1000) comprising (i) a tubular enclosure (100) and (ii) a plurality of light sources (200) configured to generate light source light (201) configured within the tubular enclosure (100), wherein the light sources (200) comprise solid state light sources, wherein the enclosure (100) comprises an enclosure material (300) that is transmissive for at least part of the light source light (201), wherein the enclosure material (300) comprises polymeric foam material (310), wherein the polymeric foam material (310) has a volume fraction of gas voids (320) relative to the total volume of the polymeric foam material (310) including the gas voids (320) selected from the range of 10-95 vol. %, wherein the tubular enclosure (100) has a tube length (L1) of at least 400 mm and a wall thickness (w1) selected from the range of 0.5-6 mm.

Claims

1. A light generating device comprising (i) a tubular enclosure and (ii) a plurality of light sources configured to generate light source light configured within the tubular enclosure, wherein the light sources comprise solid state light sources, wherein the enclosure comprises an enclosure material that is transmissive for at least part of the light source light, wherein the enclosure material comprises rigid polymeric foam material, wherein the polymeric foam material has a volume fraction of gas voids relative to the total volume of the polymeric foam material including the gas voids selected from the range of 10-95 vol. %, wherein the tubular enclosure has a tube length (L1) of at least 400 mm and a wall thickness (w1) selected from the range of 0.5-6 mm.

2. The light generating device according to claim 1, wherein the tube length (L1) is at least 1200 mm, wherein the wall thickness (w1) is at least 1 mm, and wherein the volume fraction of gas voids relative to the total volume of the polymeric foam material including the gas voids is selected from the range of 30-95 vol. %.

3. The light generating device according to claim 1, wherein the tubular enclosure comprises a gradient in size of the voids and/or a variation in wall thickness.

4. The light generating device according to claim 1, wherein the plurality of light sources comprises a subset of n1 light sources configured to generate light source light having the same spectral power distributions, wherein the tubular enclosure has an external diameter (D1), and wherein the n1 light sources of the subset of n1 light sources have a pitch (P), wherein D1≥1.5*P.

5. The light generating device according to claim 4, wherein n1 is an integer value closest to a minimum LED count value N.sub.L,M=(2.7*w1+30)/m, or larger than this integer value closest to the minimum LED count value N.sub.L,M.

6. The light generating device according to claim 1, wherein the wall thickness (w1) is larger than 1 mm and equal to or smaller than 6 mm.

7. The light generating device according to claim 1, wherein the tubular enclosure has an external diameter (D1), wherein the external diameter (D1) is selected from the range of at least 30 mm and at maximum 50 mm.

8. The light generating device according to claim 1, wherein the gas voids have a number average particle size of at least 0.02 mm and at maximum 1.8 mm.

9. The light generating device according to claim 1, wherein a first elongated part of the tubular enclosure defined by a first circular sector has a first reflectivity R1, wherein a second elongated part of the tubular enclosure defined by a second circular sector has a second reflectivity R2, wherein R1>R2.

10. The light generating device according to claim 9, wherein the first reflectivity R1 is selected from the range of at least 50% and wherein the second reflectivity is selected from the range of 5-40%.

11. The light generating device according to claim 9, wherein the gas voids in the first elongated part have a number average particle size of at maximum 0.5 mm and at minimum 0.02 mm, and wherein the gas voids in the second elongated part have a number average particle size of at least 0.6 mm and at maximum 1.8 mm.

12. The light generating device according to claim 9, wherein the first circular sector has a first central angle selected from the range of 45-315°, wherein the second circular sector has second central angle selected from the range of 45-315°, and wherein 240°≤θ1+θ2≤360°.

13. The light generating device according to claim 1, wherein the polymeric foam material is selected from the group comprising PP, SAN, PMMA, PMMI, PC, PU, PET, PEN, or a copolyester of one or more of the afore-mentioned.

14. The light generating device according to claim 1, further comprising an electronic component, wherein the electronic component is enclosed by the enclosure.

15. A luminaire comprising the light generating device according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0083] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

[0084] FIGS. 1a-1c schematically depict some embodiments;

[0085] FIGS. 2a-2c schematically depict some further embodiments;

[0086] FIGS. 3a-3c show some simulations; and

[0087] FIG. 4 schematically depict an embodiment of the luminaire.

[0088] The schematic drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0089] FIG. 1a schematically depicts a perspective view and FIG. 1b schematically depicts a cross-sectional view of an embodiment of the light generating device 1000. The light generating device 1000 comprising (i) a tubular enclosure 100 and (ii) a plurality of light sources 200 configured to generate light source light 201 configured within the tubular enclosure 100. The light sources 200 especially comprise solid state light sources, such as LEDs.

[0090] The enclosure 100 comprises an enclosure material 300 that is transmissive for at least part of the light source light 201. The enclosure material 300 comprises polymeric foam material 310. The polymeric foam material 310 has a volume fraction of gas voids 320 relative to the total volume of the polymeric foam material 310 selected from the range of 10-98 vol. %. In embodiments, the polymeric foam material 310 is selected from the group comprising PP, SAN, PMMA, PMMI, PC, PU, PET, PEN, or a copolyester of one or more of the afore-mentioned. At least part of the enclosure 100 is obtainable by a chemical foaming process or a physical foaming process.

[0091] The tubular enclosure 100 has a tube length L1 of at least 400 mm, such as at least 500 mm, and a wall thickness w1 selected from the range of 0.5-6 mm. In embodiments, tube length L1 is at least 1200 mm. In further specific embodiments, the tube length L1 is at least 1500 mm. In specific embodiments, the wall thickness w1 is at least 1 mm. In specific embodiments, the wall thickness w1 is larger than 1 mm. References D1 refers to an external diameter of the enclosure 100 and reference D2 refers to an internal diameter of the enclosure 100. The difference is the wall thickness w1. In specific embodiments, the tubular enclosure 100 has an external diameter D1, wherein the external diameter D1 is selected from the range of at least 30 mm.

[0092] The light sources 200 have a pitch P (see further also below).

[0093] Reference 350 (see FIG. 1b) indicates an end element, which may include an end closure and e.g. electronic connectors. Such end element 350 may be molded or glued to the enclosure 100. Not shown, but one or more electrical cables, or other electrical connectors, may enter the enclosure via such end element 350. In yet further specific embodiments, the volume fraction of gas voids 320 relative to the total volume of the polymeric foam material 310 is selected from the range of 30-95 vol. %. The gas voids 320 may in embodiments have a number average particle size of at least 0.2 mm and at maximum 1.8 mm.

[0094] FIG. 1b also very schematically depicts an embodiment wherein two types of light sources 200 are available, indicated with references 200′ and 200″. For instance, one type of light sources may emit white light and other type of light sources may emit white light with another correlated color temperature, or color light. Each type of light sources may have its own pitch. Hence, in embodiments the plurality of light sources 200 comprises a subset of n1 light sources 200 configured to generate light source light 201 having the same spectral power distributions, wherein the tubular enclosure 100 has an external diameter D1, and wherein the n1 light sources 200 of the subset of n1 light sources have a pitch P, wherein D1≥1.5*P.

[0095] The number of light sources may also depend to the thickness of the wall (at a fixed outer diameter). In specific embodiments, n1 is an integer value closest to a minimum LED count value N.sub.L,M=2.7*w1+30/m, or larger than this integer value closest to the minimum LED count value N.sub.L,M. This may lead to a homogeneous light distribution of the light source light escaping from the enclosure 100. As there may be more than one subset of light sources, each may have its own minimum light source count (such as LED count). For instance, in embodiments the light generating device 1000 may comprise k subsets of each n.sub.k light sources 200, wherein the spectral power distributions of light source light 201 of light sources 200 of different subsets mutually differ, wherein for each respective n.sub.k applies that it is an integer value closest to a minimum LED count value N.sub.L,M=2.7*w1+30/m, or larger than this integer value closest to the minimum LED count value N.sub.L,M.

[0096] The light generating device 1000 may further comprise an electronic component 1500. Here, the electronic component 1500 is enclosed by the enclosure 100. The electronic component may comprise a control system for controlling the light sources. Via (e.g. wireless) communication, the control system may be controlled via a user interface, though other options may also be possible, like one or more of sensor and timer that provide input to the control system.

[0097] FIG. 1c schematically depicts an embodiment of a D shape (or closed half circle shape) of the tubular enclosure 100.

[0098] Referring to FIGS. 2a-2b, in embodiments the light generating device 1000 may comprise a first elongated part 110 of the tubular enclosure 100 defined by a first circular sector 115 having a first reflectivity R1, and a second elongated part 120 of the tubular enclosure 100 defined by a second circular sector 125, having a second reflectivity R2, wherein R1>R2. Especially, the first reflectivity R1 is selected from the range of at least 50% and the second reflectivity is selected from the range of 5-40%, such as e.g. 5-30%. Here, by way of example the void percentage is larger in the first part 110 than in the second part, but alternatively or additionally, the void size may differ and/or the number of voids may differ.

[0099] In specific embodiments, the gas voids 320 in the first elongated part 110 have a number average particle size of at maximum 0.5 mm, wherein the gas voids 320 in the second elongated part 120 have a number average particle size of at least 0.6 mm and at maximum 1.8 mm. The smaller void sizes (at about equal void volume fraction) may lead to a higher reflection.

[0100] As schematically depicted the first circular sector 115 has a first central angle θ1 selected from the range of 45-315°, wherein the second circular sector 125 has second central angle θ2 selected from the range of 45-315°, and wherein 240°≤θ1+θ2≤360°.

[0101] FIG. 2c schematically depicts an embodiment wherein the end elements 350. Reference L1 indicates the total length. Part of it may be the polymeric enclosure 100 with voids. The length thereof is indicated with L1′. In embodiments, L1−200 mm≤L1′≤L1. By way of example, electronics 1500 are enclosed by an end element 350 (see on the left and on the right the dashed elements 1500).

[0102] FIG. 3a shows the LED count LC, i.e. the number of LEDs per meter as function of the wall thickness w1 for T5, T8, T10, and T12 type enclosures. Note that LED count effectively may refer to count of light emitting surfaces of light sources such as LEDs. A cluster of light emitting surfaces with mutual distances smaller than about 1 mm, such as distances smaller than about 500 μm may still be considered a single light emitting surface.

[0103] FIG. 3b shows the LED count LC as function of the external diameter D1 of enclosures. See above the comments in relation to LED count and light emitting surfaces.

[0104] FIG. 3c shows the reflection R (%) as function of the average bubble size D3 (mm) for different wall thicknesses w1, i.e. 2, 3, 4 and 5 mm wall thickness.

[0105] FIG. 4 schematically depicts an embodiment of a luminaire 2 comprising the light generating device 1000 as described above. Reference 301 indicates a user interface which may be functionally coupled with the control system 300 comprised by or functionally coupled to the lighting generating device 1000.

[0106] The term “plurality” refers to two or more.

[0107] The terms “substantially” or “essentially” herein, and similar terms, will be understood by the person skilled in the art. The terms “substantially” or “essentially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term “substantially” or the term “essentially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%.

[0108] The term “comprise” also includes embodiments wherein the term “comprises” means “consists of”.

[0109] The term “and/or” especially relates to one or more of the items mentioned before and after “and/or”. For instance, a phrase “item 1 and/or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term “comprising” may in an embodiment refer to “consisting of” but may in another embodiment also refer to “containing at least the defined species and optionally one or more other species”.

[0110] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0111] The devices, apparatus, or systems may herein amongst others be described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation, or devices, apparatus, or systems in operation.

[0112] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

[0113] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0114] Use of the verb “to comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.

[0115] The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements.

[0116] The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim, enumerating several means, several of these means may be embodied by one and the same item of hardware. 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.

[0117] The invention also provides a control system that may control the device, apparatus, or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the device, apparatus, or system, controls one or more controllable elements of such device, apparatus, or system.

[0118] The invention further applies to a device, apparatus, or system comprising one or more of the characterizing features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and/or shown in the attached drawings.

[0119] The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.