Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
  • F21K99/00—Subject matter not provided for in other groups of this subclass
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V3/00—Globes; Bowls; Cover glasses
  • F21V3/04—Globes; Bowls; Cover glasses characterised by materials, surface treatments or coatings
  • F21V3/06—Globes; Bowls; Cover glasses characterised by materials, surface treatments or coatings characterised by the material
  • F21V3/08—Globes; Bowls; Cover glasses characterised by materials, surface treatments or coatings characterised by the material the material comprising photoluminescent substances
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
  • F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
  • F21K9/20—Light sources comprising attachment means
  • F21K9/23—Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
  • F21K9/232—Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
  • F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
  • F21K9/60—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
  • F21K9/64—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V13/00—Producing particular characteristics or distribution of the light emitted by means of a combination of elements specified in two or more of main groups F21V1/00 - F21V11/00
  • F21V13/02—Combinations of only two kinds of elements
  • F21V13/08—Combinations of only two kinds of elements the elements being filters or photoluminescent elements and reflectors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
  • F21V29/50—Cooling arrangements
  • F21V29/502—Cooling arrangements characterised by the adaptation for cooling of specific components
  • F21V29/506—Cooling arrangements characterised by the adaptation for cooling of specific components of globes, bowls or cover glasses
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
  • F21V29/50—Cooling arrangements
  • F21V29/60—Cooling arrangements characterised by the use of a forced flow of gas, e.g. air
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
  • F21V29/50—Cooling arrangements
  • F21V29/70—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks
  • F21V29/83—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks the elements having apertures, ducts or channels, e.g. heat radiation holes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V3/00—Globes; Bowls; Cover glasses
  • F21V3/04—Globes; Bowls; Cover glasses characterised by materials, surface treatments or coatings
  • F21V3/06—Globes; Bowls; Cover glasses characterised by materials, surface treatments or coatings characterised by the material
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V5/00—Refractors for light sources
  • F21V5/10—Refractors for light sources comprising photoluminescent material
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V7/00—Reflectors for light sources
  • F21V7/22—Reflectors for light sources characterised by materials, surface treatments or coatings, e.g. dichroic reflectors
  • F21V7/24—Reflectors for light sources characterised by materials, surface treatments or coatings, e.g. dichroic reflectors characterised by the material
  • F21V7/26—Reflectors for light sources characterised by materials, surface treatments or coatings, e.g. dichroic reflectors characterised by the material the material comprising photoluminescent substances
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
  • F21V29/50—Cooling arrangements
  • F21V29/70—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks
  • F21V29/71—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks using a combination of separate elements interconnected by heat-conducting means, e.g. with heat pipes or thermally conductive bars between separate heat-sink elements
  • F21V29/713—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks using a combination of separate elements interconnected by heat-conducting means, e.g. with heat pipes or thermally conductive bars between separate heat-sink elements in direct thermal and mechanical contact of each other to form a single system
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
  • F21V29/85—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems characterised by the material
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V3/00—Globes; Bowls; Cover glasses
  • F21V3/02—Globes; Bowls; Cover glasses characterised by the shape
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
  • F21Y2115/00—Light-generating elements of semiconductor light sources
  • F21Y2115/10—Light-emitting diodes [LED]

Definitions

• the present invention generally relates to heat management in lighting devices.
• Heat management is an important issue within the field of illumination and, in particular, within the field of solid state based illumination, such as illumination based on light emitting diodes, LEDs.
• illumination based on light emitting diodes, LEDs.
• heat generation is commonly an undesired effect since it can affect performance and life expectance of the light sources, as well as the choice of materials and the configuration of electronics for the lighting device.
• Heat may also be produced in optical elements of the lighting device, such as in wavelength-converting components by Stokes shift losses.
• US 2011/0298371 Al discloses a LED light bulb with openings in a cover portion.
• US 3373275 A discloses a one piece molded light transmitting lens cover with masked ventilation openings.
• US 2011/0049749 Al discloses a replaceable illumination module with a cover cap which includes micro-weave materials with pore sizes large enough for air transfer but too small to convey water droplets.
• US 3253675 A discloses an apparatus for absorbing acoustic energy comprising a light-transmitting member having one or more layers of a porous material which permits the transmission of light therethrough.
• EP 2461089 Al discloses a lighting unit with a light transmissive lamp cap having a plurality of vent holes.
• a lighting device comprising at least one light source, and at least one optical element.
• the at least one optical element is arranged to transmit light emitted by the light source.
• the at least one optical element comprises a light transmissive material and at least one passage extending through the light transmissive material for allowing a flow of fluid through the optical element. Further, the passage is arranged such that a major portion of the light emitted by the at least one light source entering the passage further propagates through the light transmissive material.
• the optical element comprises a plurality of layers of light transmissive material spaced apart from each other, wherein each layer comprises at least one through-hole.
• the present aspect is based on the realization that the heat management for a lighting device may be improved by arranging a passage (or hole) in the optical element in front of the light source.
• the passage allows transfer of heat generated by the light source by means of convection through the passage.
• the term "convection" may relate to transfer of heat by fluid movement.
• the fluid flowing through the passage may be the fluid present in the lighting device, which may be of a gaseous form, such as air.
• the passage may improve dissipation of heat generated in the optical element itself, such as by Stokes shift losses in wavelength-converting materials, which optionally may be arranged in the optical element.
• the heat generated in the optical element may be transferred through the passage by the fluid flow.
• Improved heat dissipation from the lighting device may e.g. enable higher operating intensities and/or longer lifetime of the lighting device.
• the optical element is utilized to facilitate heat dissipation from the lighting device.
• the optical element may be used as a complement to (or even instead of) a traditional heat sink, thereby enabling increased overall heat dissipation from the lighting device.
• the passage is arranged such that a major portion of the light emitted by the light source entering the passage further propagates through the light transmissive material, the passage has a limited influence on the light distribution of the lighting device. In other words, the passage is arranged such that a reduced amount of light is allowed to propagate directly through the passage without passing the light transmissive material.
• the passage is formed by the fluidly
• the space between the layers of light transmissive material may allow circulation of fluid between the layers, which may further improve heat convection.
• the circulation of fluid may be adjusted by adjusting the distance of the layers of light transmissive material, which influences the turbulence of the flow of fluid in the passage.
• the term "light transmissive material” is to be widely interpreted as any material or combination of materials (or substances) admitting at least some transmission of light.
• the light transmissive material may comprise transparent and/or translucent material (such as ceramics or plastics) and, optionally, particles (e.g. for scattering and/or wavelength conversion of light) embedded therein and/or applied thereto.
• any line of sight extending from the light source and through the passage crosses the light transmissive material, whereby the influence of the passage on the light distribution of the lighting device is further reduced.
• an increased amount of light from the light source entering the passage may interact with the light transmissive material at least once upon passing the optical element.
• the light source is not directly visible from outside of the optical element through the passage, whereby glare from the light source is reduced.
• At least two of the layers of light transmissive material may be arranged such that light transmissive material of one of the two layers laterally overlap the through-hole in the other one of the two layers, whereby a major portion of the light entering one of the through-holes further propagates through at least one of the other layers of light transmissive material.
• light entering one of the through-holes may interact at least once with the light transmissive material in one of the layers upon passing (or propagating through) the optical element.
• the position of the optical element relative to the light source may be less critical with regard to reducing the amount of light entering the passage without further propagating through the light transmissive material, as the non-straight shape of the passage may (at least partially) inhibit light from passing the passage without also passing the light transmissive material.
• the optical element may be provided with a plurality of passages, whereby the convection of heat is further improved. Further, the area of the optical element exposed to the flow of fluid increases, which improves dissipation of heat from the optical element into the passages.
• the optical element may comprise a porous material comprising pores extending through the light transmissive material, whereby the pores form the passages for flow of fluid through the optical element.
• the pores may e.g. extend between two opposite surfaces of optical element.
• the extension of the pores through the optical element may be winding (or at least non-straight), whereby light emitted by the light source entering a pore further propagates through the light transmissive material surrounding the pore.
• the winding pores increase the area of the light transmissive material exposed to the flowing fluid, whereby dissipation and convection of heat is improved.
• the porous light transmissive material comprises multiple refractive index shifts at the interfaces between the light transmissive material and the voids (typically comprising the fluid) formed by the pores, whereby the optical element may be used as a diffuser of the lighting device. Multiple refractive index shifts may provide scattering of light propagating through the porous material.
• the transmissive material may preferably have a higher refractive index compared to that of the fluid (e.g. air).
• the volume of the pores may make up at least
• the light transmissive material may comprise particles for scattering (e.g. Ti0 2 , BaS0 4 and/or A1 2 0 3 particles) and/or converting a wavelength of light emitted by the light source.
• the particles in the light transmissive material may be reflective (e.g. opaque, such as white) for scattering light.
• the particles may be wavelength converting particles having an atomic (or molecular) structure having an energy gap corresponding to the energy of the light emitted by the light source. Generally, whenever light is absorbed and re-emitted by the particles, the wavelength of the light is increased. Most of the energy loss defined by the difference in energy prior to the absorption and after the re-emission is emitted as heat radiation. The heat convection through the optical element may facilitate dissipation of the heat resulting from such a wavelength conversion.
• the at least one optical element may be positioned at a distance from the at least one light source being closer than 3 mm, such as closer than 2 mm, 1 mm or 0.5 mm, which provides a reduced size of (more compact) lighting device.
• Fig. 1 is a cross-section of a lighting device having one or more through holes or passages.
• Fig. 2 is a cross-section of a lighting device according to an embodiment of the invention.
• Fig. 3 is a cross-section of a lighting device according to another embodiment of the invention.
• Fig. 4 is a cross-section of a lighting device according to yet another embodiment of the invention.
• Fig. 5 is a cross-section of an optical element of a lighting device according to yet another embodiment of the invention.
• Fig. 6 is a cross-section of a lighting device according to yet another embodiment of the invention.
• Fig. 7 is a perspective, partly cut-away, view of a lighting arrangement according an embodiment of the invention.
• Figure 1 is a cross-section of the lighting device 1.
• the lighting device 1 comprises one or more light sources 3, such as solid state based light sources (e.g. light emitting diodes, LEDs), and an optical element 5 arranged to transmit light emitted by the light sources 3.
• the optical element 5 comprises light transmissive material 7 and one or more (in the present example two) passages, or in this case through-holes, 9 extending through the light transmissive material 7 from a first surface 13 to a second surface 15 of the optical element 5.
• the passages 9 extend between opposite sides of the optical element 5.
• the passages 9 are arranged to allow a flow of fluid through the optical element 5, such as out of a space defined between the light sources 3 and the optical element 5.
• the fluid flowing through the passages 9 may be the fluid present in the lighting device 1, such as any gaseous fluid and preferably air.
• Fluid surrounding the optical element 5 circulates in and out of the passages 9 of the optical element 5, thereby providing heat convection.
• the flow of fluid removes heat present in the space between the light sources 3 and the optical element 5, which facilitates heat dissipation from the lighting device 1.
• the configuration of the passages 9 and the positioning of the light sources 3 relative to the passages 9 is adapted such that a major portion (preferably substantially all) light 16 emitted by the light sources 3 entering the passages 9 further propagates through the light transmissive material 7.
• a majority of the light emitted by the light sources 3 passing through the passages 9 interacts at least once with the light transmissive material 7.
• the passages 9 are configured such that any line of sight extending from each light source 3 and crosses a passage 9 at any point also crosses the light transmissive material 7.
• the light sources 3 are not directly visible through the passages 9 when looking at the first surface 13 of the optical element 5.
• the amount of light, which enters the passages 3 and subsequently interacts with the light transmissive material 7 is determined by the shape of the passages 9, the dimensions of the passages 9 relative to the surrounding light transmissive material 7 and the position of the passages 9 relative to the light sources 3.
• the aspect ratio of the thickness of the light transmissive material 7 to the average diameter of the passages 9 is at least 2, such as at least 4 or 6.
• the light transmissive material 7 may be significantly thicker than the width of the passages 9.
• positioning of the light sources 3 with respect to the passages 9 may be adapted to the angle of spread of the light sources 3.
• the passages 9 of the optical element 5 may be
• the passages 9 may e.g. have a substantially cylindrical shape with any convenient cross-section, such as a circular, polygon, elliptic, hyperbolic or parabolic shape.
• a lighting device 1 according to an embodiment of the invention will be described with reference to Figure 2.
• the lighting device may be similarly configured as the lighting device described with reference to Figure 1, except that the optical element 5 comprises a plurality of layers 18 of light transmissive material 7 and each layer 18 has at least one through-hole 11.
• the passages for allowing the flow of fluid through the optical element 5 are in this embodiment formed by the fluidly interconnected through-holes 11 and the spaces defined between the layers 18.
• the total volume of the layers 18 may be rather small compared to the total volume of the passages (i.e. the through-holes 11 and the space between the layers 18) for facilitating circulation of fluid in the passages and thereby improving the heat convection through the optical element 5.
• the distances between the different layers 18 may be equal to each other or vary.
• a lighting device 1 according to general embodiments of a lighting device having through holes or passages will be described with reference to Figures 3 and 4.
• the lighting device may be similarly configured as the lighting device described with reference to Figure 1 , except that the passages 9 are shaped such that an imaginary straight line between a first opening 17 and a second opening 19 of the passage 9 crosses the light transmissive material 7 of the optical element 5, whereby heat transportation through the passages 9 may be effected without causing glare from the light sources 3.
• the passages 9 may be cornered, as illustrated in Figure 3, or curved as illustrated in Figure 4.
• the passages 9 of the lighting device shown in Figure 4 may e.g.
• the first curve 21 and the second curve 23 may be interconnected by a part of the passage 9 that is substantially horizontal or slightly tilted.
• the passages 9 may have any non-straight shape allowing light emitted by the light sources entering the passages to further propagate through the light transmissive material 7.
• the optical element 5 comprising the curved or cornered passages 9 may be formed by placing two or more layers 26, 28 of light transmissive material on top of each other, wherein each layer comprises at least one recess 30, as illustrated in Figure 5.
• the two layers 26,28 are spaced apart.
• the optical element 5 may comprise two spaced apart layers split at a plane where the corner of the passages is formed.
• the recesses 30 are shaped and arranged such that, when the layers 26, 28 are joined, a recess 30 of one 26 of the layers overlaps a recess of the other 28 layer such that they together form a passage 9 extending through the optical element 5.
• the curved and/or cornered passages 9 may be formed by means of 3D printing of the optical element 5.
• a lighting device 1 according to yet another embodiment will be described with reference to Figure 6.
• the lighting device may be similarly configured as the lighting device described with reference to Figure 1 , or as described with reference to Figure 2 comprising two or more optical elements, except that the optical element 5 comprises a porous material with a plurality of pores 25 extending through the light transmissive material 7 between the first surface 13 and the second surface 15.
• the pores 25 form the passages in the optical element 5 for allowing a flow of fluid through the optical element 5.
• the pores 25 may have a relatively narrow diameter and random winding shape, whereby light emitted by the light sources entering a pore 25 further propagates through the light transmissive material 7.
• the volume of the pores may make up at least 30% of the total volume of the optical element 5 for facilitating heat convention.
• the lighting device 1 may e.g. be a retrofit LED- based lighting device, as illustrated in Figure 7.
• the lighting device may be any type of lighting arrangement and is not limited to LED-lamps or luminaires.
• the lighting device may e.g. be implemented in a lamp, luminaire, light engine or a system comprising several lighting devices.
• the lighting device 1 may be used in one or more of the following applications: shop lighting systems, home lighting systems, accent lighting systems, spot lighting systems, theatre lighting systems, decorative lighting systems, portable lighting systems, automotive lighting applications, projection systems, display systems, warning sign systems, medical lighting application systems, indicator sign systems, and household application systems.
• the lighting device 1 may optionally comprise an enclosure (or envelope) 27, which together with the heat sink 29 (or lower portion of the lighting device) encloses the optical element 5 and the light source 3.
• the enclosure 27 may have the shape of a bulb.
• the lighting device 1 may further comprise a socket 31 for coupling the lighting device 1 to a lamp fixture.
• the optical element 5 may be arranged in front of the light source 3, e.g. to cover or enclose the light source 3.
• the optical element 5 may have a sphere- like (or dome-like) shape.
• An inner volume between the optical element 5 and the light source 3 is fluidly connected to an outer volume between by the enclosure 27 and the optical element 5 via the passages 9.
• the passages 9 are arranged to enable a flow of air between the inner volume and the outer volume of the lighting device 1 to transport the heat produced from the light sources 3 and the optical element 5 to the outer volume.
• the lighting device 1 may further comprise active cooling means (not shown) arranged to produce a flow of fluid through the passages 9, preferably in direction away from the light source 3.
• the active cooling means may be configured to produce a flow of fluid in the heat conduction direction, i.e. from the inner volume to the outer volume in the lighting device 1.
• the active cooling means may enhance the flow of fluid produced by the heat convection effect.
• the active cooling means may e.g. comprise a fan.
• the light transmissive material 7 may comprise a transparent or translucent bulk material, such as glass or plastics.
• the light transmissive material 7 may further include scattering particles for scattering light emitted by the light source 3.
• the optical element 5 may comprise particles causing an exothermic reaction when illuminated such that heat is produced. Heat generated in the light transmissive material 7 may be dissipated partly via the heat convection in the passages.
• the light transmissive material 7 in the optical element 5 may comprise wavelength converting material, such as a phosphor. Particles of the wavelength converting material absorb and re-emit light through fluorescence, phosphorescence, luminescence, chemiluminscence or a combination thereof.
• suitable wavelength converting materials are organic luminescent materials based on perylene derivatives.
• the organic luminescent material may be transparent and non-scattering.
• the wavelength converting material may comprise quantum dots or quantum rods.
• Quantum dots are small crystals of semiconducting material generally having a width or diameter of only a few nanometers. When excited by incident light, a quantum dot emits light of a color determined by the size and material of the crystal. Light of a particular color can therefore be produced by adapting the size of the dots.
• Most known quantum dots with emission in the visible range are based on cadmium selenide (CdSe) with shell such as cadmium sulfide (CdS) and zinc sulfide (ZnS).
• Cadmium free quantum dots such as indium phosphide (InP), and copper indium sulfide (CuInS 2 ) and/or silver indium sulfide (AgInS 2 ) can also be used. Quantum dots show very narrow emission band and, thus, they show saturated colors. Furthermore, the emission color can be tuned by adapting the size of the quantum dots. Any type of quantum dot may be used in the light transmissive material 7.
• the light transmissive material 7 may comprise an inorganic phosphor.
• inorganic phosphor materials include, but are not limited to, cerium (Ce) doped YAG (Y 3 Al 5 0i 2 ) or LuAG (Lu 3 Al 5 0i 2 ). Ce doped YAG emits yellowish light, whereas Ce doped LuAG emits yellow-greenish light.
• examples of other inorganic phosphors materials which emit red light may include, but are not limited to ECAS and BSSN; ECAS being Ca ⁇ .
• LEDs other types of light sources than LEDs may be used, such as light sources of the incandescent, gas discharge, halogen or high intensity discharge types.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Optics & Photonics (AREA)
• Non-Portable Lighting Devices Or Systems Thereof (AREA)
• Arrangement Of Elements, Cooling, Sealing, Or The Like Of Lighting Devices (AREA)

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• 2014
  • 2014-06-20 US US14/901,861 patent/US10184651B2/en active Active
  • 2014-06-20 JP JP2016522409A patent/JP6430497B2/ja active Active
  • 2014-06-20 EP EP14731638.4A patent/EP3047199B1/en active Active
  • 2014-06-20 WO PCT/EP2014/062979 patent/WO2015000716A1/en not_active Ceased
  • 2014-06-20 CN CN201480038178.3A patent/CN105358899B/zh active Active
  • 2014-06-20 RU RU2016103406A patent/RU2673878C2/ru active

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