EP2484967A2 - Lighting unit - Google Patents
Lighting unit Download PDFInfo
- Publication number
- EP2484967A2 EP2484967A2 EP12000803A EP12000803A EP2484967A2 EP 2484967 A2 EP2484967 A2 EP 2484967A2 EP 12000803 A EP12000803 A EP 12000803A EP 12000803 A EP12000803 A EP 12000803A EP 2484967 A2 EP2484967 A2 EP 2484967A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- heat sink
- lens device
- solid state
- lighting unit
- lens
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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Classifications
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- 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
-
- 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
- F21V17/00—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages
- F21V17/005—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages with keying means, i.e. for enabling the assembling of component parts in distinctive positions, e.g. for preventing wrong mounting
-
- 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
- F21V19/00—Fastening of light sources or lamp holders
- F21V19/001—Fastening of light sources or lamp holders the light sources being semiconductors devices, e.g. LEDs
- F21V19/003—Fastening of light source holders, e.g. of circuit boards or substrates holding light sources
- F21V19/0035—Fastening of light source holders, e.g. of circuit boards or substrates holding light sources the fastening means being capable of simultaneously attaching of an other part, e.g. a housing portion or an optical component
-
- 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
- F21V29/74—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks with fins or blades
- F21V29/75—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks with fins or blades with fins or blades having different shapes, thicknesses or spacing
-
- 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
- F21V29/74—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks with fins or blades
- F21V29/77—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks with fins or blades with essentially identical diverging planar fins or blades, e.g. with fan-like or star-like cross-section
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- 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
- F21V5/007—Array of lenses or refractors for a cluster of light sources, e.g. for arrangement of multiple light sources in one plane
-
- 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
-
- 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
- F21Y2101/00—Point-like light sources
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- 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
- F21Y2105/00—Planar light sources
- F21Y2105/10—Planar light sources comprising a two-dimensional array of point-like light-generating elements
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- 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 invention relates to a lighting unit, and in particular, to a solid state lighting unit such as an LED lighting unit, and a method for manufacturing the lighting unit.
- a typical LED lighting unit 1 is shown in Figures 1 and 2 .
- the unit 1 includes a trim element 3, a plurality of lenses 5 and three LEDs 7 mounted on a printed circuit board (PCB) 9.
- the PCB 9 is mounted on a support plate 11, which in turn is mounted on a heat sink 13. Electrical cables 15 connect to the PCB 9 via a hole (not shown) formed through the heat sink 13 and support plate 11.
- the lighting unit 1 is assembled by securing the support plate 11 to the heat sink 13 using screws 17. This requires holes (not shown) formed through the support plate 11 and tapped holes (not shown) to be formed in the heat sink 13 to receive the screws 17.
- the support plate 11 and PCB 9 each have holes (not shown) formed through their bodies.
- the trim element 3 has tapped holes (not shown).
- the PCB 9, LEDs 7, lenses 5 and trim element 3 are mounted on to the support plate 11. The subassembly is held together by screws 19, which screw into the tapped holes formed in the trim element 3.
- the lighting unit 1 shown includes eighteen components and takes a significant amount of time to manufacture. This consequently leads to a high unit cost.
- the invention seeks to mitigate at least one of the afore-mentioned problems, or to at least provide an alternative to the lighting unit described above.
- a lighting unit including a lens device, at least one solid state lighting device, and a heat sink, wherein the lens device is directly coupled with the heat sink in a push fit manner thereby holding the solid state lighting device in thermal contact with the heat sink such that, in use, at least some of the heat generated by solid state lighting device is transferred to the heat sink by conduction.
- the invention significantly reduces the part count, the manufacturing time and the unit cost when compared with the traditional prior art lighting device mentioned in the introductory paragraphs, and is a more optimised solution to other known push fit coupling arrangements since the lens device is directly coupled to the heat sink.
- the invention provides a lower cost lighting unit that is easier to manufacture.
- the lens device is firmly coupled with the heat sink to fix the relative positions of the heat sink and lens device.
- the lens device can be coupled to the heat sink by means of an interference press fit. The interference fit prevents the lens device from separating from the heat sink during normal use
- At least one of the lens device and the heat sink can be arranged to deform when coupled together, and preferably plastically deform.
- the lens device can be arranged to plastically deform when inserted into the heat sink. Plastic deformation is preferred since this tends to provide a tighter more permanent fit.
- One of the lens device and the heat sink can include at least one male connector, and preferably a plurality of male connectors, and the other of the lens device and the heat sink can include at least one female connector, and preferably a plurality of female connectors. Having a plurality of male and female connectors allows the lens device to be applied to a lighting unit having only a single LED, which is centrally located.
- the plurality of male connectors can be distributed on the lens device such that they are substantially uniformly spaced and the plurality of female connectors can be distributed on the heat sink such that they are substantially uniformly spaced. Typically the number of male connectors matches the number of female connectors.
- each male connector can be deformable, and preferably plastically deformable, and /or includes at least one deformable formation, such as a rib, protrusion, or similar, and preferably a plastically deformable formation.
- each female connector can be deformable.
- the solid state lighting device can include at least one alignment formation for correctly positioning the solid state lighting device with respect to the lens device and/or heat sink prior to coupling the lens device to the heat sink. This prevents the heat sink from being damaged when the first and second parts are coupled together.
- the alignment formation can be arranged to engage the male and/or female connector(s).
- the solid state lighting device includes at least one female alignment formation, such as a hole or a recess that is arranged to engage the male connector.
- the solid state lighting device includes a plurality of female alignment formations that are each arranged to engage one of the male connectors.
- the lens device can include the male connectors and the solid state lighting device is attached to the lens device before the lens device is coupled to the heat sink. This ensures that the solid state lighting device is properly positioned relative to the lens device so that the lens device does not damage the solid state lighting device when the lens device is coupled to the heat sink. The lens device also helps to protect the solid state lighting device throughout the manufacturing process. It also provides an efficient arrangement.
- the lens device can comprise a moulded component.
- the lens device can be made from a plastic material and is preferably made by injection moulding.
- the lighting unit can include at least one tolerance element that is arranged to deform when the lens device is coupled to the heat sink, and preferably plastically deform.
- the or each tolerance element accounts for the variability in size of lighting unit components, the variability being due to manufacturing tolerances.
- a build up of manufacturing tolerances can be exhibited between the heat sink and at least one of the lens device and a trim element.
- the or each tolerance element can be substantially conical or include a substantially conical portion. This form provides good deformation characteristics.
- the lens device can include at least one of the tolerance elements.
- the lens device is coupled to the heat sink using a press.
- the press applies a substantially constant load, or a predetermined loading profile, to the lighting unit and the or each tolerance element deforms under the load. In some lighting units there will be significant deformation of the or each tolerance element, in other lighting units the deformation will be less. The amount of deformation depends on the actual size of the components for individual units.
- the or each tolerance element impinges on the solid state lighting device thereby holding the solid state lighting device in firm thermal connection with the heat sink.
- the lens device can include at least one lens member having at least one of the tolerance elements mounted thereon.
- the lens device can include a plurality of lens members and each lens member can include at least one of the tolerance elements thereon.
- the or each lens member can include a set of tolerance elements mounted thereon. Preferably there are four tolerance elements in each set arranged in a square or rectangle.
- the solid state lighting device includes at least one LED, and preferably a plurality of LEDs. When the lens device is coupled to the heat sink, the arrangement can be such that the tolerance elements surround each of the LEDs.
- the solid state lighting device can include a printed circuit board (PCB).
- the heat sink can include an extruded body.
- the extruded body can include at least one of the male and/or female connectors formed therein.
- the lens device is coupled directly with the extruded body via the male and/or female connector(s).
- the heat sink can include, when viewed from an end face, a plurality of cores and the solid state lighting device includes a plurality of LEDs, wherein each LED is seated over one of the cores.
- each LED is seated over a heat sink core which enables heat to be removed effectively from all of the LEDs. This improves the performance and life span of each of the LEDs.
- the number of cores matches the number of LEDs.
- the multi-core arrangement provides a lighter unit than an oversized single core heat sink.
- the heat sink includes a central portion and each of the cores is connected to the central portion by a connector portion such as a spoke or web.
- each core is substantially cylindrical.
- Each core can include a plurality of fins that protrude outwards therefrom.
- the heat sink can include a plurality of support arms.
- Each support arm can be arranged to extend radially from one of the cores.
- Each support arm can be connected to its respective core and spaced apart from the adjacent core.
- Each support arm can be separated from the adjacent core by a bulbous recess, which undercuts the root of the support arm where it joins to the core.
- each support arm can include a female connector such as a bore formed therein for receiving one of the male connectors.
- the heat sink is made from a material having good thermal conduction properties such as aluminium or copper.
- each support arm can include a longitudinal slot formed therein that protrudes into the bore. This enables the bores to be easily formed during the extrusion process and does not require the bores to be drilled during a subsequent manufacturing process.
- the slots also enable the heat sink, in some embodiments, to deform by a small amount when the bores receive their respective male connectors, thereby loading the male connectors.
- the heat sink includes a through bore for receiving electrical cables that are arranged to connect the solid state lighting device to a power source.
- the lighting unit can include thermal interface means, such as a thermal interface pad or paste, for connecting the solid state lighting device to the heat sink.
- the thermal interface means is located between the solid state lighting device and the heat sink and provides a thermal pathway from the solid state lighting device to the heat sink such that at least some of the heat emitted from the solid state lighting device is transferred to the heat sink via the thermal interfacing means by way of conduction.
- the thermal interfacing means promotes heat transfer and optionally can be arranged to adhere the solid state lighting device to the heat sink. Alternatively, the solid state lighting device can be held directly in contact with the heat sink in order to provide a thermally conductive pathway between the solid sate lighting device and the heat sink.
- a method for manufacturing a lighting unit including providing a solid state lighting device, a lens device, and a heat sink, and directly coupling together the heat sink and lens device such that the solid state lighting device is held in thermal contact with the heat sink, the arrangement being such that, in use, at least some of the heat generated by solid state lighting device is transferred to the heat sink by conduction.
- the method can include coupling the lens device and the heat sink together using a press.
- the method can include deforming at least one of the lens device and the heat sink when the first and second parts are coupled together by the press, and preferably plastically deforming the lens device.
- one of the lens device and the heat sink includes at least one male connector, and preferably a plurality of male connectors, and the other of the lens device and heat sink includes at least one female connector, and preferably a plurality of female connectors.
- the method can include deforming, and preferably plastically deforming, at least one male connector when coupling the lens device and heat sink together.
- the method can include coupling the solid state lighting device to the lens device prior to coupling the lens device to the heat sink. This helps to prevent the solid state lighting device from being damaged when the lens device is coupled with the heat sink.
- the method can include providing the lens device having a least one male connector, and preferably a plurality of male connectors, and the solid state lighting device having at least one female alignment formation, and preferably a plurality of female alignment formations, and coupling the male connector to the female alignment formation, thereby correctly aligning the orientations of the lens device and the solid state lighting device.
- the method can include providing at least one deformable tolerance element, and deforming the or each tolerance element when the lens device and heat sink are coupled together, and preferably plastically deforming the tolerance element.
- the method can include the press applying a predetermined load, or a predetermined loading profile, to the push fit coupling means and the extent of deformation of the or each tolerance element is determined by manufacturing tolerance(s) of at least one of the following: the lens device, the heat sink, the solid state lighting device and a trim element.
- the method permanently couples the first and second parts together.
- the method can include forming the heat sink by an extrusion process.
- the method can include forming the lens device by a moulding process, such as injection moulding.
- the lighting unit can be arranged according to any configuration described herein.
- a lighting unit including a lens device, at least one solid state lighting device, a heat sink and push fit coupling means arranged to couple together the heat sink and at least one of the lens device and the solid state lighting device, wherein the solid state lighting device is held in thermal contact with the heat sink such that, in use, at least some of the heat generated by solid state lighting device is transferred to the heat sink by conduction.
- the invention significantly reduces the part count, the manufacturing time and the unit cost when compared with the prior art lighting device mentioned in the introductory paragraphs.
- the invention provides a lower cost lighting unit that is easier to manufacture.
- the coupling means includes first and second parts and the lens device and the heat sink and / or the solid state lighting device and the heat sink are coupled together by coupling the first and second parts.
- the lens device can include one of the first and second parts of the push fit coupling means.
- the heat sink can include one of the first and second parts of the push fit coupling means.
- the lens device includes one of the first and second parts and the heat sink includes the other of the first and second parts.
- first and second parts of the push fit coupling means can be arranged for an interference press fit.
- At least one of the first and second parts of the push fit coupling means can be arranged to deform when the first and second parts are coupled together, and preferably plastically deform.
- the first part of the push fit coupling means can be arranged to plastically deform when inserted into the second part of the coupling. Plastic deformation is preferred since this tends to provide a tighter more permanent fit.
- the first part of the push fit coupling means can include at least one male connector and the second part of the push fit coupling means can include at least one female connector.
- the first part can include a plurality of male connectors and the second part can include at a plurality of female connectors. Having a plurality of male and female connectors allows the lens unit to be applied to a lighting unit having only a single LED, which is centrally located.
- the plurality of male connectors can be distributed on the lens device such that they are substantially uniformly spaced and the plurality of female connectors can be distributed on the heat sink such that they are substantially uniformly spaced. Typically the number of male connectors matches the number of female connectors.
- each male connector can be deformable, and preferably plastically deformable, and /or includes at least one deformable formation, such as a rib, protrusion, or similar, and preferably a plastically deformable formation.
- each female connector can be deformable.
- the lighting unit can be arranged according to any configuration described herein.
- a lighting unit including a solid state lighting device, a lens device, a heat sink, wherein one of the heat sink and the lens device includes a plurality of deformable male connectors and the other of the heat sink and the lens device includes a plurality of female connectors, the lens device is directly push fit coupled to the heat sink by the male and female connectors, the arrangement being such that the solid state lighting device is held in thermal contact with the heat sink by the lens device such that, in use, at least some of the heat generated by solid state lighting device is transferred to the heat sink by conduction.
- the male connectors are plastically deformable.
- the lens device includes the plurality of male connectors and the heat sink includes the plurality of female connectors. Each male connector is arranged for an interference fit with one of the female connectors.
- FIGS 3 to 6 show a lighting unit 100 in accordance with the first embodiment of the invention.
- the lighting unit 100 includes a trim element 102, a lens unit 104, three LEDs 106, a PCB 108, optionally a thermal interface pad (or paste) 110, a heat sink 112 and electrical cables 114.
- the lens unit 104 directs light emitted by the LEDs 106 and includes a disc member 116, three lenses 118, three connector members 120, and a lip 122 (see Figures 4a-d ).
- the lens unit 104 comprises a moulded component and therefore the disc member 116, lenses 118, connector members 120 and lip 122 are integrally formed.
- the lens unit 104 is made from a plastics material such as acrylic and is formed by injection moulding.
- the disc member 116 provides a protective cover for the lenses 118.
- the disc member 116 has a planar outer surface 124.
- the three lenses 118 are located on the inner surface 126 of the disc member.
- Each lens 118 protrudes out of the plane of the disc member 116 and has a central axial bore 128 and a flattened annular portion 130.
- the plane of the annular portion 130 is arranged substantially parallel to the plane of the disc member 116.
- Each annular part 130 includes four crush pins 132 protruding substantially perpendicularly therefrom.
- Each crush pin 132 has a substantially conical form. When the lighting unit 100 is assembled, the crush pins 132 impinge on the PCB 108 and collapse under load.
- the purpose of the crush pins 132 is to account for a build up in manufacturing tolerances between the heat sink and the trim element 102. For embodiments not having a trim element 102, the crush pins 132 are not strictly necessary.
- Each of the lenses 118 is axially aligned with one of the LEDs 106.
- the connector members 120 are arranged to hold the lighting unit 100 together when assembled.
- the connector members 120 effectively replace the screws 17,19 from the prior art arrangement.
- Each of the connector members 120 protrudes out of the plane of the disc member 116 and is arranged substantially perpendicularly to the inner surface 126.
- Each connector member 120 is located adjacent two lenses 118 towards a peripheral part of the disc member 116 (adjacent the lip 122).
- Each connector member 120 tapers along its length from a broader proximal end 134 to a narrower distal end 136.
- Each connector member 120 includes four crush ribs 138 that run longitudinally along the connector member 120 and protrude radially outwards therefrom.
- each rib 138 tapers towards the distal end 136.
- each connector member includes a counter sink formation 138.
- the LEDs 106 are mounted on the PCB 108.
- the PCB 108 is attached to the heat sink 112 by a thermal interface pad (or paste) 110.
- the thermal interface pad or paste 110 adheres the PCB 108 to the heat sink 112 and aids the thermal transfer of heat generated by the LEDs 106 to the heat sink 112.
- the heat sink 112 comprises an aluminium extrusion (see Figures 5a-5e ).
- the heat sink 112 includes three bores 140 that are arranged substantially parallel to the longitudinal axis of the heat sink. Each of the bores 140 is arranged to receive one of the connector members 120. Each bore 140 has a counter sunk recess 140a at its entrance that is arranged to receive the counter sink formation 156. Preferably each bore has a substantially circular cross-section, though other cross-sections can be used.
- the heat sink 112 is substantially prismatic in form.
- the heat sink 112 has a central portion 142.
- the central portion 142 includes an axial through bore 144 for receiving the electrical cables 114.
- Three rib-like members 146 protrude radially outwards from the central portion 142.
- the rib-like members 146 are uniformly distributed about the central portion, the arrangement being such that the separation between the centre lines of each of the rib-like members 146 when viewed in plan is 120°.
- Each rib-like member 146 includes a solid core 148.
- Twelve cooling fins 150 of varying lengths protrude radially outwards from each core 148. The lengths of the fins 150 are such that the tips of some of the fins 150 lie on a pitch circle thereby providing the heat sink 112 with a notionally cylindrical form.
- Each core 148 has a support arm 152 protruding substantially radially therefrom.
- the bores 140 for receiving the connector members 120 are formed in the support arms 152.
- the bores 140 have longitudinal openings 154 formed through the support arm 152.
- the bores 140 and openings 154 are formed during the extrusion process. The openings allow the bores to be formed more easily during the extrusion process.
- the openings 154 can be arranged to enable the support arms 152 to deform by a small amount when the connector members 120 are inserted into the bores 140.
- the counter sunk recesses 140a are formed in one end face of the heat sink 112 at the mouths of the bores 140.
- the arrangement of the heat sink 112 is such that it provides cores 148 for each of the LEDs and facilitates good air flow around the core. Bulbous recesses 154 are formed between each support arm and adjacent core 148.
- the trim element 102 comprises an annular member.
- the annular member includes an internal lip (not shown) that is arranged to engage with the lip 122 on the lens unit 104. In its coupled state, the lens unit 104 is seated within the annular trim element 102.
- the LEDs 106 and electrical cables 114 are connected to the PCB 108.
- the PCB 108 is attached to the lens unit 104 by inserting connector members 120 into alignment holes 121 formed in the PCB 108. This ensures that the LEDs 106 are properly aligned with the lens 118, thereby preventing them from being damaged when attached to the heat sink 112.
- the lens unit 104 also provides some protection to the PCB 108 and LEDs 106 throughout the process since its structure partially surrounds and extends beyond the LEDs and PCB 108. This helps to reduce the number of rejected lighting units due to damage to the solid state lighting device.
- the electrical cables 114 are threaded through the central axial bore 144 formed in the heat sink and the thermal interface pad (or paste) 110 is applied to the heat sink and/or PCB 108.
- the connector members 120 and bores 140 are sized for an interference press fit, that is, the diameter (width and/or depth) of the connector members 120 is slightly larger than the diameter (width and/or depth) of the bore 140.
- the lens unit 104 is attached to the heat sink 112 using a press.
- the trim element 102 is located over the heat sink 112.
- the lens unit 104 is then inserted into the trim element 102, with the connector members 120 being pushed into the bores 140.
- the lens unit 104 is pushed into position via the press, which applies a predetermined load or loading profile to the lens unit.
- the crush ribs 138 on the connector members 120 engage side walls of the bores 140 and plastically deform under the load applied by the bores to provide a tight fitting engagement between the lens unit 104 and the heat sink 112.
- the crush pins 132 impinge upon the LED 106 or PCB 108.
- the crush pins 132 plastically deform to varying degrees.
- the crush pins 132 force the PCB 108 to hold the PCB 108 tightly against the heat sink 112. This enables heat transfer between the LEDs 106 and the heat sink 112 to take place by conduction.
- the interaction between the connector members 120 and the heat sink 112 provides sufficient force to hold the lighting unit 100 together in its assembled state during normal usage.
- the arrangement of the lighting unit 100, the manufacturing process leads to a simplified lighting unit, and one that can be manufactured significantly more quickly and economically..
- each of the LEDs 106 overlies one of the heat sink cores 148. This ensures good heat transfer from each LED into the heat sink and that the heat sink has the capacity to absorb the heat emitted by the LED in the immediate vicinity of the LED. This improves the performance of the LEDs 106 and increases the life of each LED.
- a second embodiment is shown in Figures 7-9d .
- the lighting unit 200 according to the second embodiment includes a trim element 202, a lens unit 204, an LED 206, a PCB 208, a thermal interface pad (or paste) 110, and a heat sink 212.
- the second embodiment is similar to the first embodiment except that the lighting unit 200 only includes one LED 206. Accordingly, the lens unit 204 only includes a single lens 218.
- the lens unit 204 includes crush pins 232 and three connector members 220 having crush ribs 238.
- the heat sink 212 is adapted to a lighting unit having a single LED 206.
- the heat sink 212 includes a single core 248, which is centrally located. Three sets of five fins 250 protrude radially outwards from the core 248. Each set of fins is separated by radial support arms 252, which each include a bore 240 and a longitudinal opening 254.
- radial support arms 252 which each include a bore 240 and a longitudinal opening 254.
- the connector members can be formed in the heat sink and the bores formed in the lens unit.
- the number of connectors can be different. For example, there is at least one male connector and at least one female connector. Typically embodiments include y male connectors, where y is in the range 2 to 6, and preferably in the range 3 to 4. The number of female connectors (bores or similar) is equal to the number of male connectors.
- the heat sink can include at least one male connector and the lens device can include at least one female connector, in addition to, or as an alternative to the arrangement described above.
- the lens unit can be attached to the heat sink via an intermediate component.
- the push fit coupling can be provided by other components.
- the trim element can be arranged to couple with the heat sink, the arrangement being such that when coupled to the heat sink, the trim element urges the lens unit towards the heat sink, and the lens unit urges the PCB against the heat sink.
- the trim element can include male connectors that are arranged to couple with the female connectors formed in the heat sink.
- the trim element can be in the form of a sleeve that can couple with the outer surface of the heat sink, there being an interference fit between the trim element and the heat sink.
- the heat sink can be made from any other suitable material having a high thermal conductivity such as copper.
- the heat sink can include a different number of cores. Typically the number of cores is matched to the number of LEDs. The number of fins on each core can be different.
- the bores can be formed into a different part of the heat sink from the support arms. In which case, the support arms are not strictly necessary.
- the PCB can be mounted directly onto the heat sink.
- the lens unit can be attached to the heat sink via an intermediate component.
- the connector members can be arranged to elastically deform in addition, or as an alternative, to the plastic deformation.
- the heat sink can be of a different, more conventional construction.
- the lens unit can be of the type known as Total Internal Reflection (TIR) unit, which includes at least one lens and at least one reflector in a combined unit.
- TIR Total Internal Reflection
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- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Optics & Photonics (AREA)
- Geometry (AREA)
- Arrangement Of Elements, Cooling, Sealing, Or The Like Of Lighting Devices (AREA)
- Non-Portable Lighting Devices Or Systems Thereof (AREA)
Abstract
Description
- The invention relates to a lighting unit, and in particular, to a solid state lighting unit such as an LED lighting unit, and a method for manufacturing the lighting unit.
- A typical LED lighting unit 1 is shown in
Figures 1 and2 . - The unit 1 includes a
trim element 3, a plurality oflenses 5 and threeLEDs 7 mounted on a printed circuit board (PCB) 9. The PCB 9 is mounted on a support plate 11, which in turn is mounted on aheat sink 13.Electrical cables 15 connect to the PCB 9 via a hole (not shown) formed through theheat sink 13 and support plate 11. The lighting unit 1 is assembled by securing the support plate 11 to theheat sink 13 usingscrews 17. This requires holes (not shown) formed through the support plate 11 and tapped holes (not shown) to be formed in theheat sink 13 to receive thescrews 17. The support plate 11 and PCB 9 each have holes (not shown) formed through their bodies. Thetrim element 3 has tapped holes (not shown). The PCB 9,LEDs 7,lenses 5 andtrim element 3 are mounted on to the support plate 11. The subassembly is held together byscrews 19, which screw into the tapped holes formed in thetrim element 3. - The lighting unit 1 shown includes eighteen components and takes a significant amount of time to manufacture. This consequently leads to a high unit cost.
- Another problem with the arrangement shown in
Figure 1 is that sometimes during manufacture the PCB 9 is misaligned when attaching it to theheat sink 13. In this situation, insertingscrews 17 can cause damage to the LEDs. Also, the LEDs and PCB are easily damaged during the manufacturing process, for example due to mishandling of the components. Therefore it is desirable to have some way of protecting those items during manufacture of the lighting unit. - Other known lighting units are disclosed in
EP2053666 ,US2004/0066142 andCN201237095 . These all teach the idea of push fit coupling a lens device to a support plate and attaching the support plate to the heat sink by some other means. While this is concept is an improvement on the traditional lighting unit described above, it still does not provide a fully optimised arrangement for manufacture and assembly. - The invention seeks to mitigate at least one of the afore-mentioned problems, or to at least provide an alternative to the lighting unit described above.
- According to a first aspect of the invention there is provided a lighting unit, including a lens device, at least one solid state lighting device, and a heat sink, wherein the lens device is directly coupled with the heat sink in a push fit manner thereby holding the solid state lighting device in thermal contact with the heat sink such that, in use, at least some of the heat generated by solid state lighting device is transferred to the heat sink by conduction.
- The invention significantly reduces the part count, the manufacturing time and the unit cost when compared with the traditional prior art lighting device mentioned in the introductory paragraphs, and is a more optimised solution to other known push fit coupling arrangements since the lens device is directly coupled to the heat sink. Thus the invention provides a lower cost lighting unit that is easier to manufacture.
- Advantageously the lens device is firmly coupled with the heat sink to fix the relative positions of the heat sink and lens device. For example, the lens device can be coupled to the heat sink by means of an interference press fit. The interference fit prevents the lens device from separating from the heat sink during normal use
- Advantageously at least one of the lens device and the heat sink can be arranged to deform when coupled together, and preferably plastically deform. For example, the lens device can be arranged to plastically deform when inserted into the heat sink. Plastic deformation is preferred since this tends to provide a tighter more permanent fit.
- One of the lens device and the heat sink can include at least one male connector, and preferably a plurality of male connectors, and the other of the lens device and the heat sink can include at least one female connector, and preferably a plurality of female connectors. Having a plurality of male and female connectors allows the lens device to be applied to a lighting unit having only a single LED, which is centrally located. The plurality of male connectors can be distributed on the lens device such that they are substantially uniformly spaced and the plurality of female connectors can be distributed on the heat sink such that they are substantially uniformly spaced. Typically the number of male connectors matches the number of female connectors.
- Advantageously the or each male connector can be deformable, and preferably plastically deformable, and /or includes at least one deformable formation, such as a rib, protrusion, or similar, and preferably a plastically deformable formation. Additionally, or alternatively, each female connector can be deformable.
- Advantageously the solid state lighting device can include at least one alignment formation for correctly positioning the solid state lighting device with respect to the lens device and/or heat sink prior to coupling the lens device to the heat sink. This prevents the heat sink from being damaged when the first and second parts are coupled together.
- Advantageously the alignment formation can be arranged to engage the male and/or female connector(s). In preferred embodiments the solid state lighting device includes at least one female alignment formation, such as a hole or a recess that is arranged to engage the male connector. Preferably the solid state lighting device includes a plurality of female alignment formations that are each arranged to engage one of the male connectors. Advantageously the lens device can include the male connectors and the solid state lighting device is attached to the lens device before the lens device is coupled to the heat sink. This ensures that the solid state lighting device is properly positioned relative to the lens device so that the lens device does not damage the solid state lighting device when the lens device is coupled to the heat sink. The lens device also helps to protect the solid state lighting device throughout the manufacturing process. It also provides an efficient arrangement.
- Advantageously the lens device can comprise a moulded component. The lens device can be made from a plastic material and is preferably made by injection moulding.
- Advantageously the lighting unit can include at least one tolerance element that is arranged to deform when the lens device is coupled to the heat sink, and preferably plastically deform. The or each tolerance element accounts for the variability in size of lighting unit components, the variability being due to manufacturing tolerances. A build up of manufacturing tolerances can be exhibited between the heat sink and at least one of the lens device and a trim element.
- The or each tolerance element can be substantially conical or include a substantially conical portion. This form provides good deformation characteristics.
- Advantageously the lens device can include at least one of the tolerance elements. In an advantageous manufacturing process, the lens device is coupled to the heat sink using a press. The press applies a substantially constant load, or a predetermined loading profile, to the lighting unit and the or each tolerance element deforms under the load. In some lighting units there will be significant deformation of the or each tolerance element, in other lighting units the deformation will be less. The amount of deformation depends on the actual size of the components for individual units.
- In the assembled lighting unit, the or each tolerance element impinges on the solid state lighting device thereby holding the solid state lighting device in firm thermal connection with the heat sink.
- The lens device can include at least one lens member having at least one of the tolerance elements mounted thereon. The lens device can include a plurality of lens members and each lens member can include at least one of the tolerance elements thereon. The or each lens member can include a set of tolerance elements mounted thereon. Preferably there are four tolerance elements in each set arranged in a square or rectangle.
- The solid state lighting device includes at least one LED, and preferably a plurality of LEDs. When the lens device is coupled to the heat sink, the arrangement can be such that the tolerance elements surround each of the LEDs. The solid state lighting device can include a printed circuit board (PCB).
- Advantageously the heat sink can include an extruded body. This gives the component a substantially prismatic form. Advantageously the extruded body can include at least one of the male and/or female connectors formed therein. The lens device is coupled directly with the extruded body via the male and/or female connector(s).
- Advantageously the heat sink can include, when viewed from an end face, a plurality of cores and the solid state lighting device includes a plurality of LEDs, wherein each LED is seated over one of the cores. Thus each LED is seated over a heat sink core which enables heat to be removed effectively from all of the LEDs. This improves the performance and life span of each of the LEDs. The number of cores matches the number of LEDs. The multi-core arrangement provides a lighter unit than an oversized single core heat sink.
- The heat sink includes a central portion and each of the cores is connected to the central portion by a connector portion such as a spoke or web. Preferably each core is substantially cylindrical. Each core can include a plurality of fins that protrude outwards therefrom.
- Advantageously the heat sink can include a plurality of support arms. Each support arm can be arranged to extend radially from one of the cores. Each support arm can be connected to its respective core and spaced apart from the adjacent core. Each support arm can be separated from the adjacent core by a bulbous recess, which undercuts the root of the support arm where it joins to the core.
- Advantageously each support arm can include a female connector such as a bore formed therein for receiving one of the male connectors.
- The heat sink is made from a material having good thermal conduction properties such as aluminium or copper.
- Advantageously each support arm can include a longitudinal slot formed therein that protrudes into the bore. This enables the bores to be easily formed during the extrusion process and does not require the bores to be drilled during a subsequent manufacturing process. The slots also enable the heat sink, in some embodiments, to deform by a small amount when the bores receive their respective male connectors, thereby loading the male connectors.
- The heat sink includes a through bore for receiving electrical cables that are arranged to connect the solid state lighting device to a power source.
- The lighting unit can include thermal interface means, such as a thermal interface pad or paste, for connecting the solid state lighting device to the heat sink. The thermal interface means is located between the solid state lighting device and the heat sink and provides a thermal pathway from the solid state lighting device to the heat sink such that at least some of the heat emitted from the solid state lighting device is transferred to the heat sink via the thermal interfacing means by way of conduction. The thermal interfacing means promotes heat transfer and optionally can be arranged to adhere the solid state lighting device to the heat sink. Alternatively, the solid state lighting device can be held directly in contact with the heat sink in order to provide a thermally conductive pathway between the solid sate lighting device and the heat sink.
- According to another aspect of the invention there is provided a method for manufacturing a lighting unit, said method including providing a solid state lighting device, a lens device, and a heat sink, and directly coupling together the heat sink and lens device such that the solid state lighting device is held in thermal contact with the heat sink, the arrangement being such that, in use, at least some of the heat generated by solid state lighting device is transferred to the heat sink by conduction.
- Advantageously the method can include coupling the lens device and the heat sink together using a press. Advantageously the method can include deforming at least one of the lens device and the heat sink when the first and second parts are coupled together by the press, and preferably plastically deforming the lens device.
- Advantageously one of the lens device and the heat sink includes at least one male connector, and preferably a plurality of male connectors, and the other of the lens device and heat sink includes at least one female connector, and preferably a plurality of female connectors.
- Advantageously the method can include deforming, and preferably plastically deforming, at least one male connector when coupling the lens device and heat sink together.
- Advantageously the method can include coupling the solid state lighting device to the lens device prior to coupling the lens device to the heat sink. This helps to prevent the solid state lighting device from being damaged when the lens device is coupled with the heat sink. Advantageously the method can include providing the lens device having a least one male connector, and preferably a plurality of male connectors, and the solid state lighting device having at least one female alignment formation, and preferably a plurality of female alignment formations, and coupling the male connector to the female alignment formation, thereby correctly aligning the orientations of the lens device and the solid state lighting device.
- Advantageously the method can include providing at least one deformable tolerance element, and deforming the or each tolerance element when the lens device and heat sink are coupled together, and preferably plastically deforming the tolerance element.
- Advantageously the method can include the press applying a predetermined load, or a predetermined loading profile, to the push fit coupling means and the extent of deformation of the or each tolerance element is determined by manufacturing tolerance(s) of at least one of the following: the lens device, the heat sink, the solid state lighting device and a trim element.
- Advantageously the method permanently couples the first and second parts together.
- Advantageously the method can include forming the heat sink by an extrusion process.
- Advantageously the method can include forming the lens device by a moulding process, such as injection moulding.
- Advantageously the lighting unit can be arranged according to any configuration described herein.
- According to another aspect of the invention there is provided a lighting unit, including a lens device, at least one solid state lighting device, a heat sink and push fit coupling means arranged to couple together the heat sink and at least one of the lens device and the solid state lighting device, wherein the solid state lighting device is held in thermal contact with the heat sink such that, in use, at least some of the heat generated by solid state lighting device is transferred to the heat sink by conduction.
- The invention significantly reduces the part count, the manufacturing time and the unit cost when compared with the prior art lighting device mentioned in the introductory paragraphs. Thus the invention provides a lower cost lighting unit that is easier to manufacture.
- Advantageously the coupling means includes first and second parts and the lens device and the heat sink and / or the solid state lighting device and the heat sink are coupled together by coupling the first and second parts. The lens device can include one of the first and second parts of the push fit coupling means. The heat sink can include one of the first and second parts of the push fit coupling means. Advantageously in preferred embodiments the lens device includes one of the first and second parts and the heat sink includes the other of the first and second parts. Thus the solid sate lighting device can be held in thermal contact with the heat sink by the lens device.
- Advantageously the first and second parts of the push fit coupling means can be arranged for an interference press fit.
- Advantageously at least one of the first and second parts of the push fit coupling means can be arranged to deform when the first and second parts are coupled together, and preferably plastically deform. For example, the first part of the push fit coupling means can be arranged to plastically deform when inserted into the second part of the coupling. Plastic deformation is preferred since this tends to provide a tighter more permanent fit.
- The first part of the push fit coupling means can include at least one male connector and the second part of the push fit coupling means can include at least one female connector. Preferably the first part can include a plurality of male connectors and the second part can include at a plurality of female connectors. Having a plurality of male and female connectors allows the lens unit to be applied to a lighting unit having only a single LED, which is centrally located. The plurality of male connectors can be distributed on the lens device such that they are substantially uniformly spaced and the plurality of female connectors can be distributed on the heat sink such that they are substantially uniformly spaced. Typically the number of male connectors matches the number of female connectors.
- Advantageously the or each male connector can be deformable, and preferably plastically deformable, and /or includes at least one deformable formation, such as a rib, protrusion, or similar, and preferably a plastically deformable formation. Additionally, or alternatively, each female connector can be deformable.
- Advantageously the lighting unit can be arranged according to any configuration described herein.
- According to another aspect of the invention there is provided a lighting unit, including a solid state lighting device, a lens device, a heat sink, wherein one of the heat sink and the lens device includes a plurality of deformable male connectors and the other of the heat sink and the lens device includes a plurality of female connectors, the lens device is directly push fit coupled to the heat sink by the male and female connectors, the arrangement being such that the solid state lighting device is held in thermal contact with the heat sink by the lens device such that, in use, at least some of the heat generated by solid state lighting device is transferred to the heat sink by conduction.
- The male connectors are plastically deformable. The lens device includes the plurality of male connectors and the heat sink includes the plurality of female connectors. Each male connector is arranged for an interference fit with one of the female connectors.
- Embodiments of the invention will now be described by way of example, with reference to the accompanying drawings, wherein:
-
Figure 1 is an exploded side view of a prior art lighting unit; -
Figure 2 is a schematic plan view of the prior art lighting unit ofFigure 1 showing the relative positions of LEDs in relation to a heat sink core; -
Figure 3 is an exploded side view of a first embodiment of the invention; -
Figures 4a-e show views of a lens unit included in the first embodiment -
Figures 5a-e show views of a heat sink included in the first embodiment; -
Figure 6 is a schematic plan view showing how LEDs included in the first embodiment sit in relation to the heat sink cores ofFigures 5a-e ; -
Figure 7 is an exploded side view of a second embodiment of the invention; -
Figures 8a-e show views of a lens unit included in the second embodiment of the invention; and -
Figures 9a-e show views of a heat sink included in the second embodiment. -
Figures 3 to 6 show alighting unit 100 in accordance with the first embodiment of the invention. Thelighting unit 100 includes atrim element 102, alens unit 104, threeLEDs 106, aPCB 108, optionally a thermal interface pad (or paste) 110, aheat sink 112 andelectrical cables 114. - The
lens unit 104 directs light emitted by theLEDs 106 and includes a disc member 116, threelenses 118, threeconnector members 120, and a lip 122 (seeFigures 4a-d ). Thelens unit 104 comprises a moulded component and therefore the disc member 116,lenses 118,connector members 120 andlip 122 are integrally formed. Preferably thelens unit 104 is made from a plastics material such as acrylic and is formed by injection moulding. - The disc member 116 provides a protective cover for the
lenses 118. The disc member 116 has a planarouter surface 124. The threelenses 118 are located on theinner surface 126 of the disc member. Eachlens 118 protrudes out of the plane of the disc member 116 and has a centralaxial bore 128 and a flattenedannular portion 130. The plane of theannular portion 130 is arranged substantially parallel to the plane of the disc member 116. Eachannular part 130 includes fourcrush pins 132 protruding substantially perpendicularly therefrom. Eachcrush pin 132 has a substantially conical form. When thelighting unit 100 is assembled, the crush pins 132 impinge on thePCB 108 and collapse under load. The purpose of the crush pins 132 is to account for a build up in manufacturing tolerances between the heat sink and thetrim element 102. For embodiments not having atrim element 102, the crush pins 132 are not strictly necessary. - Each of the
lenses 118 is axially aligned with one of theLEDs 106. - The
connector members 120 are arranged to hold thelighting unit 100 together when assembled. Theconnector members 120 effectively replace thescrews connector members 120 protrudes out of the plane of the disc member 116 and is arranged substantially perpendicularly to theinner surface 126. Eachconnector member 120 is located adjacent twolenses 118 towards a peripheral part of the disc member 116 (adjacent the lip 122). - Each
connector member 120 tapers along its length from a broaderproximal end 134 to a narrowerdistal end 136. Eachconnector member 120 includes fourcrush ribs 138 that run longitudinally along theconnector member 120 and protrude radially outwards therefrom. - Each
rib 138 tapers towards thedistal end 136. At theproximal end 134, each connector member includes acounter sink formation 138. - The
LEDs 106 are mounted on thePCB 108. ThePCB 108 is attached to theheat sink 112 by a thermal interface pad (or paste) 110. The thermal interface pad orpaste 110 adheres thePCB 108 to theheat sink 112 and aids the thermal transfer of heat generated by theLEDs 106 to theheat sink 112. - The
heat sink 112 comprises an aluminium extrusion (seeFigures 5a-5e ). Theheat sink 112 includes threebores 140 that are arranged substantially parallel to the longitudinal axis of the heat sink. Each of thebores 140 is arranged to receive one of theconnector members 120. Eachbore 140 has a counter sunk recess 140a at its entrance that is arranged to receive thecounter sink formation 156. Preferably each bore has a substantially circular cross-section, though other cross-sections can be used. - Since the heat sink is formed by an extrusion process, the
heat sink 112 is substantially prismatic in form. Theheat sink 112 has acentral portion 142. Thecentral portion 142 includes an axial throughbore 144 for receiving theelectrical cables 114. Three rib-like members 146 protrude radially outwards from thecentral portion 142. The rib-like members 146 are uniformly distributed about the central portion, the arrangement being such that the separation between the centre lines of each of the rib-like members 146 when viewed in plan is 120°. Each rib-like member 146 includes asolid core 148. Twelve coolingfins 150 of varying lengths protrude radially outwards from eachcore 148. The lengths of thefins 150 are such that the tips of some of thefins 150 lie on a pitch circle thereby providing theheat sink 112 with a notionally cylindrical form. - Each
core 148 has asupport arm 152 protruding substantially radially therefrom. Thebores 140 for receiving theconnector members 120 are formed in thesupport arms 152. Thebores 140 havelongitudinal openings 154 formed through thesupport arm 152. Thebores 140 andopenings 154 are formed during the extrusion process. The openings allow the bores to be formed more easily during the extrusion process. Optionally theopenings 154 can be arranged to enable thesupport arms 152 to deform by a small amount when theconnector members 120 are inserted into thebores 140. - The counter sunk recesses 140a are formed in one end face of the
heat sink 112 at the mouths of thebores 140. - The arrangement of the
heat sink 112 is such that it providescores 148 for each of the LEDs and facilitates good air flow around the core.Bulbous recesses 154 are formed between each support arm andadjacent core 148. - The
trim element 102 comprises an annular member. The annular member includes an internal lip (not shown) that is arranged to engage with thelip 122 on thelens unit 104. In its coupled state, thelens unit 104 is seated within theannular trim element 102. - Manufacture of the
lighting unit 100 will now be described with references toFigures 3 and6 . TheLEDs 106 andelectrical cables 114 are connected to thePCB 108. ThePCB 108 is attached to thelens unit 104 by insertingconnector members 120 into alignment holes 121 formed in thePCB 108. This ensures that theLEDs 106 are properly aligned with thelens 118, thereby preventing them from being damaged when attached to theheat sink 112. Furthermore, thelens unit 104 also provides some protection to thePCB 108 andLEDs 106 throughout the process since its structure partially surrounds and extends beyond the LEDs andPCB 108. This helps to reduce the number of rejected lighting units due to damage to the solid state lighting device. - The
electrical cables 114 are threaded through the centralaxial bore 144 formed in the heat sink and the thermal interface pad (or paste) 110 is applied to the heat sink and/orPCB 108. - The
connector members 120 and bores 140 are sized for an interference press fit, that is, the diameter (width and/or depth) of theconnector members 120 is slightly larger than the diameter (width and/or depth) of thebore 140. - The
lens unit 104 is attached to theheat sink 112 using a press. Thetrim element 102 is located over theheat sink 112. Thelens unit 104 is then inserted into thetrim element 102, with theconnector members 120 being pushed into thebores 140. Thelens unit 104 is pushed into position via the press, which applies a predetermined load or loading profile to the lens unit. As thelens unit 104 moves into its final position, thecrush ribs 138 on theconnector members 120 engage side walls of thebores 140 and plastically deform under the load applied by the bores to provide a tight fitting engagement between thelens unit 104 and theheat sink 112. The crush pins 132 impinge upon theLED 106 orPCB 108. Depending on the relative sizes of trim element,lens unit 104 andheat sink 112, the crush pins 132 plastically deform to varying degrees. When thelens unit 104 is seated correctly in thetrim element 102 the crush pins 132 force thePCB 108 to hold thePCB 108 tightly against theheat sink 112. This enables heat transfer between theLEDs 106 and theheat sink 112 to take place by conduction. The interaction between theconnector members 120 and theheat sink 112 provides sufficient force to hold thelighting unit 100 together in its assembled state during normal usage. The arrangement of thelighting unit 100, the manufacturing process leads to a simplified lighting unit, and one that can be manufactured significantly more quickly and economically.. - When in the assembled state, it is apparent from
Figure 6 that each of theLEDs 106 overlies one of theheat sink cores 148. This ensures good heat transfer from each LED into the heat sink and that the heat sink has the capacity to absorb the heat emitted by the LED in the immediate vicinity of the LED. This improves the performance of theLEDs 106 and increases the life of each LED. - A second embodiment is shown in
Figures 7-9d . Thelighting unit 200 according to the second embodiment includes atrim element 202, alens unit 204, anLED 206, aPCB 208, a thermal interface pad (or paste) 110, and aheat sink 212. The second embodiment is similar to the first embodiment except that thelighting unit 200 only includes oneLED 206. Accordingly, thelens unit 204 only includes a single lens 218. - The
lens unit 204 includes crush pins 232 and threeconnector members 220 havingcrush ribs 238. - The
heat sink 212 is adapted to a lighting unit having asingle LED 206. Theheat sink 212 includes asingle core 248, which is centrally located. Three sets of fivefins 250 protrude radially outwards from thecore 248. Each set of fins is separated byradial support arms 252, which each include abore 240 and alongitudinal opening 254. Thus the second embodiment shares a similar simple structure to the first embodiment and is manufactured in a similar manner. Accordingly, the second embodiment also has the same manufacturing and cost benefits as the first embodiment. - It will be apparent to the skilled person that modifications can be made to the above embodiments that still fall within the scope of the invention, for example the connector members can be formed in the heat sink and the bores formed in the lens unit.
- The number of connectors can be different. For example, there is at least one male connector and at least one female connector. Typically embodiments include y male connectors, where y is in the range 2 to 6, and preferably in the
range 3 to 4. The number of female connectors (bores or similar) is equal to the number of male connectors. - The heat sink can include at least one male connector and the lens device can include at least one female connector, in addition to, or as an alternative to the arrangement described above.
- The lens unit can be attached to the heat sink via an intermediate component.
- The push fit coupling can be provided by other components. For example, the trim element can be arranged to couple with the heat sink, the arrangement being such that when coupled to the heat sink, the trim element urges the lens unit towards the heat sink, and the lens unit urges the PCB against the heat sink. The trim element can include male connectors that are arranged to couple with the female connectors formed in the heat sink. Alternatively the trim element can be in the form of a sleeve that can couple with the outer surface of the heat sink, there being an interference fit between the trim element and the heat sink.
- The heat sink can be made from any other suitable material having a high thermal conductivity such as copper.
- The heat sink can include a different number of cores. Typically the number of cores is matched to the number of LEDs. The number of fins on each core can be different.
- The bores can be formed into a different part of the heat sink from the support arms. In which case, the support arms are not strictly necessary.
- The PCB can be mounted directly onto the heat sink.
- The lens unit can be attached to the heat sink via an intermediate component.
- The connector members can be arranged to elastically deform in addition, or as an alternative, to the plastic deformation.
- The heat sink can be of a different, more conventional construction.
- The lens unit can be of the type known as Total Internal Reflection (TIR) unit, which includes at least one lens and at least one reflector in a combined unit.
Claims (19)
- A lighting unit, including a lens device (1040, at least one solid state lighting device (106,108), and a heat sink (112), characterised in that the lens device (104) is directly coupled with the heat sink (112) in a push fit manner thereby holding the solid state lighting device (106,108) in thermal contact with the heat sink (112) such that, in use, at least some of the heat generated by solid state lighting device (106,108) is transferred to the heat sink (112) by conduction.
- A lighting unit according to claim 1, wherein the lens device (104) and the heat sink (112) are arranged for an interference press fit.
- A lighting unit according to claim 1 or 2, wherein at least one of the lens device (104) and the heat sink (112) is arranged to deform when coupled together, and preferably plastically deform.
- A lighting unit according to any one of the preceding claims, wherein one of the heat sink (112) and the lens device (104) includes at least one male connector (120) and the other of the heat sink (112) and the lens device (104) includes at least one female connector (140).
- A lighting unit according to claim 4, wherein the or each male connector (120) is deformable, and preferably plastically deformable, and/or includes at least one deformable formation (138), such as a rib, protrusion, or similar, and preferably a plastically deformable formation (138).
- A lighting unit according to claim 4 or 5, wherein the heat sink (112) includes an extruded body having at least one of the male and/or female connectors (120,140) formed therein.
- A lighting unit according to any one of the preceding claims, wherein the solid state lighting device (106,108) includes at least one alignment formation (121) for correctly positioning the solid state lighting device (106,108) with respect to the lens device (104) and/or heat sink (112) prior to coupling the lens device (104) to the heat sink (112), and preferably the alignment formation (121) is arranged to engage the male and/or female connector(s) (120,140).
- A lighting unit according to any one of the preceding claims, including at least one tolerance element (132) that is arranged to deform when the lens device (104) is coupled to the heat sink (112), and preferably plastically deform.
- A lighting unit according to claim 8, wherein the or each tolerance element (132) holds the solid state lighting device (106,108) in thermal contact with the heat sink (112).
- A lighting unit according to claim 8 or 9, wherein the lens device (104) includes at least one of the tolerance elements (132), and preferably heat sink (112) the lens device (104) includes at least one lens member (118) having at least one of the tolerance elements (132) mounted thereon.
- A lighting unit according to any one of the preceding claims, wherein the heat sink (112) includes, when viewed from an end face, a plurality of cores (148) and the solid state lighting device (106,108) includes a plurality of LEDs (106), wherein each LED (106) is seated over one of the cores (148).
- A lighting unit according to claim 11, wherein the heat sink (112) includes a plurality of support arms (152) each having a bore (140) formed therein for receiving one of the male connectors (120), and preferably each support arm (152) includes a longitudinal slot (154) formed therein.
- A lighting unit according to any one of the preceding claims, including thermal interface means (110), such as a thermal interface pad or paste, for connecting the solid state lighting device (106,108) to the heat sink (112).
- A method for manufacturing a lighting unit, said method including providing a solid state lighting device (106,108), a lens device (104), and a heat sink (112), and characterised by directly coupling together the heat sink (112) and lens device (104) such that the solid state lighting device (106,108) is held in thermal contact with the heat sink (112), the arrangement being such that, in use, at least some of the heat generated by solid state lighting device (106,108) is transferred to the heat sink (112) by conduction.
- A method according to claim 14, including coupling the lens device (104) and heat sink (112) together using a press.
- A method according to claim 14 or 15, including deforming at least one of the lens device (104) and the heat sink (112) when coupling them together, and preferably plastically deforming the lens device (104).
- A method according to any one of claims 14 to 16, including coupling the solid state lighting device (106,108) to the lens device (104) prior to coupling the lens device (104) to the heat sink (112).
- A method according to any one of claims 14 to 17, including providing at least one deformable tolerance element (132), and deforming the or each tolerance element (132) when the lens device (104) and heat sink (112) are coupled together, and preferably plastically deforming the tolerance element (132).
- A method according to claim 18 when dependent on claim 15, wherein the press applies a predetermined load, or load profile, to at least one of the lens device (104) and the heat sink (112) and the extent of deformation of the or each tolerance element (132) is determined by manufacturing tolerance(s) of at least one of the following: the lens device (104), the heat sink (112), the solid state lighting device (106,108) and a trim element (102).
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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GB1102073.2A GB2487912B (en) | 2011-02-07 | 2011-02-07 | Lighting unit |
Publications (2)
Publication Number | Publication Date |
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EP2484967A2 true EP2484967A2 (en) | 2012-08-08 |
EP2484967A3 EP2484967A3 (en) | 2012-10-24 |
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ID=43836312
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP12000803A Withdrawn EP2484967A3 (en) | 2011-02-07 | 2012-02-07 | Lighting unit |
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EP (1) | EP2484967A3 (en) |
GB (1) | GB2487912B (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2014190368A1 (en) * | 2013-05-29 | 2014-12-04 | Zizala Lichtsysteme Gmbh | Lighting device for a vehicle headlight |
FR3026360A1 (en) * | 2014-09-30 | 2016-04-01 | Valeo Vision | DEVICE FOR POSITIONING ON AN OPTICAL DEVICE OF A MODULE COMPRISING A LIGHT SOURCE |
ITUA20164252A1 (en) * | 2016-06-16 | 2017-12-16 | Francesco Masullo | Blackdome Led Module |
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US20040066142A1 (en) | 2002-10-03 | 2004-04-08 | Gelcore, Llc | LED-based modular lamp |
EP2053666A1 (en) | 2007-10-23 | 2009-04-29 | iGUZZINI ILLUMINAZIONE S.p.A. | Heat dissipation device for LEDs and related production method |
CN201237095Y (en) | 2008-07-08 | 2009-05-13 | 东莞市贻嘉光电科技有限公司 | LED lamp |
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US7815338B2 (en) * | 2008-03-02 | 2010-10-19 | Altair Engineering, Inc. | LED lighting unit including elongated heat sink and elongated lens |
GB2463057A (en) * | 2008-08-30 | 2010-03-03 | Design 360 Ltd | Light emitting diode lighting housing comprising a reflector and heat sink |
US8152336B2 (en) * | 2008-11-21 | 2012-04-10 | Journée Lighting, Inc. | Removable LED light module for use in a light fixture assembly |
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2011
- 2011-02-07 GB GB1102073.2A patent/GB2487912B/en active Active
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2012
- 2012-02-07 EP EP12000803A patent/EP2484967A3/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040066142A1 (en) | 2002-10-03 | 2004-04-08 | Gelcore, Llc | LED-based modular lamp |
EP2053666A1 (en) | 2007-10-23 | 2009-04-29 | iGUZZINI ILLUMINAZIONE S.p.A. | Heat dissipation device for LEDs and related production method |
CN201237095Y (en) | 2008-07-08 | 2009-05-13 | 东莞市贻嘉光电科技有限公司 | LED lamp |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2014190368A1 (en) * | 2013-05-29 | 2014-12-04 | Zizala Lichtsysteme Gmbh | Lighting device for a vehicle headlight |
US9803825B2 (en) | 2013-05-29 | 2017-10-31 | Zkw Group Gmbh | Lighting device for a vehicle headlight |
FR3026360A1 (en) * | 2014-09-30 | 2016-04-01 | Valeo Vision | DEVICE FOR POSITIONING ON AN OPTICAL DEVICE OF A MODULE COMPRISING A LIGHT SOURCE |
WO2016050625A1 (en) * | 2014-09-30 | 2016-04-07 | Valeo Vision | Device for positioning a module comprising a light source on an optical device |
US10605423B2 (en) | 2014-09-30 | 2020-03-31 | Valeo Vision | Device for positioning a module comprising a light source on an optical device |
ITUA20164252A1 (en) * | 2016-06-16 | 2017-12-16 | Francesco Masullo | Blackdome Led Module |
Also Published As
Publication number | Publication date |
---|---|
GB2487912B (en) | 2014-11-12 |
GB201102073D0 (en) | 2011-03-23 |
EP2484967A3 (en) | 2012-10-24 |
GB2487912A (en) | 2012-08-15 |
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